Anne-Kristin Solbakk

• Asko, Olgerta; Volehaugen, Vegard Akselsson; Llorens, Ana?s; Funderud, Ingrid; Leske, Sabine Liliana & Ivanovic, Jugoslav [Show all 13 contributors for this article] (2025). Predictive encoding of auditory sequences in the human prefrontal cortex. bioRxiv - the preprint server for biology. doi: 10.1101/2025.08.22.671264. Full text in Research Archive Show summary

  Abstract Humans extract regularities from the environment to form expectations that guide perception and optimize behavior. Although the prefrontal cortex (PFC) is central to this process, the relative contributions of orbitofrontal (OFC) and lateral PFC (LPFC) remain unclear. Here, we show that the brain tracks sound regularities in an auditory deviance detection task to predict when a target deviant will occur. Intracranial EEG in epilepsy patients reveals prefrontal engagement, with earlier expectancy-related modulation in OFC and later modulation in LPFC. Connectivity analyses indicate bidirectional and asymmetrical expectancy-related information exchange between the two areas, with a first lead by OFC, consistent with its role in initiating predictive encoding. Converging causal evidence shows that OFC lesions abolish sensitivity to expectancy, whereas LPFC lesions yield only modest effects not significantly different from controls. Together, these results provide electrophysiological and causal evidence for distinct, temporally organized contributions of prefrontal subregions to predictive processing. Significance Statement The human brain builds probabilistic associations capturing the dynamic environmental structure in a predictive manner. The ability to encode and deploy predictive information to anticipate future events relies on the prefrontal cortex (PFC). However, the specific roles of PFC subregions in this process remain unclear. Here, we provide converging electrophysiological and causal lesion evidence on the distinct involvement of the orbital and lateral PFC in generating anticipatory neural signals based on probabilistic auditory structure.

• Rogers, Adam Austin; Halvari, Anne Elisabeth M.; Solbakk, Anne-Kristin & Johnsen, Jan-Are Kolset (2025). Testing Dental Anxiety and Self-Care Behaviours as Mediators of the Association Between Executive Functioning and Oral Health Among Young Adults. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. doi: 10.1111/cdoe.13047. Full text in Research Archive
• Leske, Sabine Liliana; Endestad, Tor; Volehaugen, Vegard Akselsson; Foldal, Maja Dyhre; Blenkmann, Alejandro Omar & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2025). Beta oscillations predict the envelope sharpness in a rhythmic beat sequence. Scientific Reports. 15(1). doi: 10.1038/s41598-025-86895-y. Full text in Research Archive Show summary

  Periodic sensory inputs entrain oscillatory brain activity, reflecting a neural mechanism that might be fundamental to temporal prediction and perception. Most environmental rhythms and patterns in human behavior, such as walking, dancing, and speech do not, however, display strict isochrony but are instead quasi-periodic. Research has shown that neural tracking of speech is driven by modulations of the amplitude envelope, especially via sharp acoustic edges, which serve as prominent temporal landmarks. In the same vein, research on rhythm processing in music supports the notion that perceptual timing precision varies systematically with the sharpness of acoustic onset edges, conceptualized in the beat bin hypothesis. Increased envelope sharpness induces increased precision in localizing a sound in time. Despite this tight relationship between envelope shape and temporal processing, it is currently unknown how the brain uses predictive information about envelope features to optimize temporal perception. With the current EEG study, we show that the predicted sharpness of the amplitude envelope is encoded by pre-target neural activity in the beta band (15¨C25 Hz), and has an impact on the temporal perception of target sounds. We used probabilistic sound cues in a timing judgment task to inform participants about the sharpness of the amplitude envelope of an upcoming target sound embedded in a beat sequence. The predictive information about the envelope shape modulated task performance and pre-target beta power. Interestingly, these conditional beta-power modulations correlated positively with behavioral performance in the timing judgment task and with perceptual temporal precision in a click-alignment task. This study provides new insight into the neural processes underlying prediction of the sharpness of the amplitude envelope during beat perception, which modulate the temporal perception of sounds. This finding could reflect a process that is involved in temporal prediction, exerting top-down control on neural entrainment via the prediction of acoustic edges in the auditory stream.

• Fuhrer, Julian; Glette, Kyrre; Ivanovic, Jugoslav; Larsson, P?l Gunnar; Bekinschtein, Tristan & Kochen, Silvia [Show all 11 contributors for this article] (2025). Direct brain recordings reveal implicit encoding of structure in random auditory streams. Scientific Reports. 15. doi: 10.1038/s41598-025-98865-5. Full text in Research Archive Show summary

  The brain excels at processing sensory input, even in rich or chaotic environments. Mounting evidence attributes this to sophisticated internal models of the environment that draw on statistical structures in the unfolding sensory input. Understanding how and where such modeling proceeds is a core question in statistical learning and predictive processing. In this context, we address the role of transitional probabilities as an implicit structure supporting the encoding of the temporal structure of a random auditory stream. Leveraging information-theoretical principles and the high spatiotemporal resolution of intracranial electroencephalography, we analyzed the trial-by-trial high-frequency activity representation of transitional probabilities. This unique approach enabled us to demonstrate how the brain automatically and continuously encodes structure in random stimuli and revealed the involvement of a network outside of the auditory system, including hippocampal, frontal, and temporal regions. Our work provides a comprehensive picture of the neural correlates of automatic encoding of implicit structure that can be the crucial substrate for the swift detection of patterns and unexpected events in the environment.

• Weber, Jan; Solbakk, Anne-Kristin; Blenkmann, Alejandro Omar; Anais, Llorens; Funderud, Ingrid & Leske, Sabine Liliana [Show all 11 contributors for this article] (2024). Ramping dynamics and theta oscillations reflect dissociable signatures during rule-guided human behavior. Nature Communications. 15(1). doi: 10.1038/s41467-023-44571-7. Full text in Research Archive
• Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Anais, Llorens; Lin, Jack J.; Chang, Edward F. & Brunner, Peter [Show all 12 contributors for this article] (2024). Anatomical registration of intracranial electrodes. Robust model-based localization and deformable smooth brain-shift compensation methods. Journal of Neuroscience Methods. ISSN 0165-0270. 404. doi: 10.1016/j.jneumeth.2024.110056. Full text in Research Archive
• Huster, Rene J¨¹rgen; Thunberg, Christina; Solbakk, Anne-Kristin; Gravholt, Claus H. & Fjermestad, Krister Westlye (2024). Inhibitory deficits in Klinefelter syndrome are secondary to deficits in the auditory and motor domain. NeuroImage: Clinical. 44. doi: 10.1016/j.nicl.2024.103674. Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Doelling, Keith & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2024). Rhythm-based Temporal Expectations: Unique Contributions of Predictability and Periodicity. Journal of Cognitive Neuroscience. ISSN 0898-929X. doi: 10.1162/jocn_a_02261. Full text in Research Archive
• Asko, Olgerta; Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Foldal, Maja Dyhre; Anais, Llorens & Funderud, Ingrid [Show all 10 contributors for this article] (2024). Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex. eLIFE. 13. doi: 10.7554/eLife.86386. Full text in Research Archive
• Weber, Jan; Iwama, Gabriela; Solbakk, Anne-Kristin; Blenkmann, Alejandro Omar; Larsson, P?l Gunnar & Ivanovic, Jugoslav [Show all 9 contributors for this article] (2023). Subspace partitioning in the human prefrontal cortex resolves cognitive interference. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 120(28). doi: 10.1073/pnas.2220523120. Full text in Research Archive Show summary

  The human prefrontal cortex (PFC) constitutes the structural basis underlying flexible cognitive control, where mixed-selective neural populations encode multiple task features to guide subsequent behavior. The mechanisms by which the brain simultaneously encodes multiple task¨Crelevant variables while minimizing interference from task-irrelevant features remain unknown. Leveraging intracranial recordings from the human PFC, we first demonstrate that competition between coexisting representations of past and present task variables incurs a behavioral switch cost. Our results reveal that this interference between past and present states in the PFC is resolved through coding partitioning into distinct low-dimensional neural states; thereby strongly attenuating behavioral switch costs. In sum, these findings uncover a fundamental coding mechanism that constitutes a central building block of flexible cognitive control.

• Raposo, Isabel; Szczepanski, Sara M.; Haaland, Kathleen; Endestad, Tor; Solbakk, Anne-Kristin & Knight, Robert T. [Show all 7 contributors for this article] (2023). Periodic attention deficits after frontoparietal lesions provide causal evidence for rhythmic attentional sampling. Current Biology. ISSN 0960-9822. 33(22), p. 4893¨C4904. doi: 10.1016/j.cub.2023.09.065. Full text in Research Archive
• Fjermestad, Krister Westlye; Bergh, Nathalie; Fleten, Susanne Kyte; Huster, Rene J¨¹rgen; Gravholt, C. & Solbakk, Anne-Kristin (2023). Mentalization and cognitive skills in men with Klinefelter syndrome versus non-clinical controls. Psychiatry Research Communications. 3(2). doi: 10.1016/j.psycom.2023.100116. Full text in Research Archive Show summary

  We investigated cognition and mentalization skills, defined as the ability to understand one's own and others' intentions and emotions, in men with Klinefelter Syndrome (KS). The sample was 26 men with KS and 26 non-clinical male controls aged 19¨C65 years. We measured mentalization with the Reading the Mind in the Eyes Test (RMET) and cognition with neuropsychological tests. The results showed that men with KS had significantly lower scores on the RMET compared to controls. However, the group difference was not significant when controlling for IQ. There were more significant correlations between cognitive domains and mentalization skills in the KS group than for controls. In regression models, cognitive domains explained up to 54% of the variance in mentalization skills for men with KS, compared to 15% for controls. The men with KS struggled particularly with interpreting neutral and negative emotional states relative to the control group. We conclude that men with KS exhibit mentalization difficulties, which are strongly linked to their cognitive abilities, and especially their deficits in verbal learning. Interventions aimed at enhancing language and other neuropsychological functions, as well as mentalization skills, are warranted.

• Fjermestad, Krister Westlye; Finnbakk, R.R.; Solbakk, Anne-Kristin; Gravholt, C.H. & Huster, Rene J¨¹rgen (2023). Subjective versus objective sleep in men with Klinefelter syndrome. Orphanet Journal of Rare Diseases. 18(1). doi: 10.1186/s13023-023-02822-2. Full text in Research Archive Show summary

  Objectives To investigate sleep among men with Klinefelter syndrome (KS). Method We compared the sleep domains latency, disturbance, and efficiency in 30 men with KS (M age?=?36.7?years, SD?=?10.6) to 21 age-matched non-KS controls (M age?=?36.8?years, SD?=?14.4). Actigraphs were used to objectively measure sleep across 7?days and nights. Participants also completed a sleep diary over the same period, and the Pittsburgh Sleep Quality Index (PSQI). Results The mean correlation between the objective and subjective sleep measures was lower for the KS sample (M r?=?.15) than for controls (M r?=?.34). Sleep disturbance was significantly larger in the KS sample, as measured by actigraphy (p?=?.022, d?=?0.71) and the PSQI (p?=?.037, d?=?0.61). In regression models predicting sleep domains from KS status, age, educational level, vocational status, IQ, and mental health, KS status was not a significant predictor. Higher age was associated with more actigraphy-measured sleep disturbance. Higher educational level and being employed were associated with better sleep efficiency. Conclusions Sleep disturbance may be a particular problem for men with KS and should be measured with complimentary methods.

• Anais, Llorens; Bellier, Ludovic; Blenkmann, Alejandro Omar; Ivanovic, Jugoslav; Larsson, P?l Gunnar & Lin, Jack J. [Show all 9 contributors for this article] (2023). Decision and response monitoring during working memory are sequentially represented in the human insula. iScience. 26(10). doi: 10.1016/j.isci.2023.107653. Full text in Research Archive Show summary

  Emerging research supports a role of the insula in human cognition. Here, we used intracranial EEG to investigate the spatiotemporal dynamics in the insula during a verbal working memory (vWM) task. We found robust effects for theta, beta, and high frequency activity (HFA) during probe presentation requiring a decision. Theta band activity showed differential involvement across left and right insulae while sequential HFA modulations were observed along the anteroposterior axis. HFA in anterior insula tracked decision making and subsequent HFA was observed in posterior insula after the behavioral response. Our results provide electrophysiological evidence of engagement of different insula subregions in both decision-making and response monitoring during vWM and expand our knowledge of the role of the insula in complex human behavior.

• Rogers, Adam Austin; Halvari, Anne Elisabeth M¨¹nster; Johnsen, Jan-Are Kolset & Solbakk, Anne-Kristin (2023). Executive functioning as a moderator of flossing behaviour among young adults: a temporal self-regulation theory perspective. Health Psychology and Behavioral Medicine. 11(1), p. 1¨C18. doi: 10.1080/21642850.2023.2249972. Full text in Research Archive Show summary

  Background - Flossing among young adults is often infrequent and barriers not completely understood. One explanation concerns the capacity for executive functioning (EF) during the self-regulation of behaviour.<p> <p>Methods - Using Temporal Self-Regulation Theory (TST) as a framework to explore EF, young adults from Norwegian universities completed a survey that measured monthly flossing frequency, flossing-related intentions and behavioural prepotency (BP), and EF using the Behaviour Rating Inventory of Executive Function ¨C Adult Version (BRIEF-A).<p> <p>Results - Data from 362 participants were analysed. The TST-model explained a substantial proportion of variance in monthly flossing (R2?=?0.74), and flossing was associated directly with intention and BP, and interactions between intention and both BP and global-EF. Sub-domains of EF were explored using the same model, revealing that behavioural regulation processes, specifically those related to emotional control and shifting between tasks, offered better fit. Simple slopes revealed that moderation effects were only present at lower levels of BP.<p> <p>Conclusion - EF plays a role in moderating the translation of intentions into flossing behaviour. Specifically, emotional control and task-shifting appear to be influential, and this influence increases when habitual and environmental support (i.e. BP) is reduced. Overcoming EF-barriers may represent a key step in establishing flossing behaviours.

• Fuhrer, Julian; Glette, Kyrre; Anais, Llorens; Endestad, Tor; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2023). Quantifying evoked responses through information-theoretical measures. Frontiers in Neuroinformatics. 17. doi: 10.3389/fninf.2023.1128866. Full text in Research Archive Show summary

  Information theory is a viable candidate to advance our understanding of how the brain processes information generated in the internal or external environment. With its universal applicability, information theory enables the analysis of complex data sets, is free of requirements about the data structure, and can help infer the underlying brain mechanisms. Information-theoretical metrics such as Entropy or Mutual Information have been highly beneficial for analyzing neurophysiological recordings. However, a direct comparison of the performance of these methods with well-established metrics, such as the t- test, is rare. Here, such a comparison is carried out by evaluating the novel method of Encoded Information with Mutual Information, Gaussian Copula Mutual Information, Neural Frequency Tagging, and t -test. We do so by applying each method to event-related potentials and event-related activity in different frequency bands originating from intracranial electroencephalography recordings of humans and marmoset monkeys. Encoded Information is a novel procedure that assesses the similarity of brain responses across experimental conditions by compressing the respective signals. Such an information-based encoding is attractive whenever one is interested in detecting where in the brain condition effects are present.

• Johnson, Elizabeth L.; Chang, William K.; Dewar, Callum D.; Sorensen, Donna; Lin, Jack J. & Solbakk, Anne-Kristin [Show all 12 contributors for this article] (2022). Orbitofrontal cortex governs working memory for temporal order. Current Biology. ISSN 0960-9822. 32(9), p. R410¨CR411. doi: 10.1016/j.cub.2022.03.074. Full text in Research Archive
• Olsen, Alexander; Dennis, Emily L.; Stubberud, Jan Egil; Hovenden, Elizabeth S.; Solbakk, Anne-Kristin & Endestad, Tor [Show all 10 contributors for this article] (2022). Regional brain volume prior to treatment is linked to outcome after cognitive rehabilitation in traumatic brain injury. NeuroImage: Clinical. 35. doi: 10.1016/j.nicl.2022.103126. Full text in Research Archive Show summary

  Cognitive rehabilitation is useful for many after traumatic brain injury (TBI), but we lack critical knowledge about which patients benefit the most from different approaches. Advanced neuroimaging techniques have provided important insight into brain pathology and systems plasticity after TBI, and have potential to inform new practices in cognitive rehabilitation. In this study, we aimed to identify candidate structural brain measures with relevance for rehabilitation of cognitive control (executive) function after TBI. Twenty-eight patients (9 female, mean age 40.5 (SD = 13.04) years) with TBI (>21 months since injury) that participated in a randomized controlled cognitive rehabilitation trial (NCT02692352) were included in the analyses. Regional brain volume was extracted from T1-weighted MRI scans before treatment using tensor-based morphometry. Both positive and negative associations between treatment outcome (everyday cognitive control function) and regional brain volume were observed. The most robust associations between regional brain volume and improvement in function were observed in midline fronto-parietal regions, including the anterior and posterior cingulate cortices. The study provides proof of concept and valuable insight for planning future studies focusing on neuroimaging in cognitive rehabilitation after TBI.

• Foldal, Maja Dyhre; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Endestad, Tor & Solbakk, Anne-Kristin (2022). Attentional modulation of beta-power aligns with the timing of behaviorally relevant rhythmic sounds. Cerebral Cortex. ISSN 1047-3211. 33(5), p. 1876¨C1894. doi: 10.1093/cercor/bhac179. Full text in Research Archive
• Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Ivanovic, Jugoslav; Larsson, P?l Gunnar; Knight, Robert Thomas & Endestad, Tor (2022). Modeling intracranial electrodes. A simulation platform for the evaluation of localization algorithms. Frontiers in Neuroinformatics. 16, p. 1¨C20. doi: 10.3389/fninf.2022.788685. Full text in Research Archive Show summary

  Introduction Intracranial electrodes are implanted in patients with drug-resistant epilepsy as part of their pre-surgical evaluation. This allows the investigation of normal and pathological brain functions with excellent spatial and temporal resolution. The spatial resolution relies on methods that precisely localize the implanted electrodes in the cerebral cortex, which is critical for drawing valid inferences about the anatomical localization of brain function. Multiple methods have been developed to localize the electrodes, mainly relying on pre-implantation MRI and post-implantation computer tomography (CT) images. However, they are hard to validate because there is no ground truth data to test them and there is no standard approach to systematically quantify their performance. In other words, their validation lacks standardization. Our work aimed to model intracranial electrode arrays and simulate realistic implantation scenarios, thereby providing localization algorithms with new ways to evaluate and optimize their performance. Results We implemented novel methods to model the coordinates of implanted grids, strips, and depth electrodes, as well as the CT artifacts produced by these. We successfully modeled realistic implantation scenarios, including different sizes, inter-electrode distances, and brain areas. In total, ¡«3,300 grids and strips were fitted over the brain surface, and ¡«850 depth electrode arrays penetrating the cortical tissue were modeled. Realistic CT artifacts were simulated at the electrode locations under 12 different noise levels. Altogether, ¡«50,000 thresholded CT artifact arrays were simulated in these scenarios, and validated with real data from 17 patients regarding the coordinates¡¯ spatial deformation, and the CT artifacts¡¯ shape, intensity distribution, and noise level. Finally, we provide an example of how the simulation platform is used to characterize the performance of two cluster-based localization methods. Conclusion We successfully developed the first platform to model implanted intracranial grids, strips, and depth electrodes and realistically simulate thresholded CT artifacts and their noise. These methods provide a basis for developing more complex models, while simulations allow systematic evaluation of the performance of electrode localization techniques. The methods described in this article, and the results obtained from the simulations, are freely available via open repositories. A graphical user interface implementation is also accessible via the open-source iElectrodes toolbox.

• Skjeldal, Ola; Skandsen, Toril; Kinge, Einar; Glott, Thomas & Solbakk, Anne-Kristin (2022). Langvarige plager etter hjernerystelse. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 142(12). doi: 10.4045/tidsskr.21.0713. Full text in Research Archive Show summary

  Hjernerystelse er vanlig og forl?per oftest uten komplikasjoner. Vedvarende symptomer opptrer imidlertid hos 10¨C15 %. Slike postcommotiosymptomer domineres av somatiske, kognitive og emosjonelle symptomer. Tilstanden er vanligst hos personer med tidligere somatiske og psykiske helseplager. ?rsakene bak langvarige symptomer etter hjernerystelse er uklare, men en biopsykososial forklaringsmodell regnes i dag som best egnet grunnlag for diagnostikk og behandling. Denne kliniske oversiktsartikkelen er basert p? sentral litteratur og egne kliniske erfaringer med pasienter som har slike langvarige postcommotiosymptomer.

• Fuhrer, Julian; Blenkmann, Alejandro Omar; Endestad, Tor; Solbakk, Anne-Kristin & Glette, Kyrre (2022). Complexity-based Encoded Information Quantification in Neurophysiological Recordings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). p. 2319¨C2323. doi: 10.1109/EMBC48229.2022.9871501. Full text in Research Archive Show summary

  Brain activity differs vastly between sleep, cognitive tasks, and action. Information theory is an appropriate concept to analytically quantify these brain states. Based on neurophysiological recordings, this concept can handle complex data sets, is free of any requirements about the data structure, and can infer the present underlying brain mechanisms. Specifically, by utilizing algorithmic information theory, it is possible to estimate the absolute information contained in brain responses. While current approaches that apply this theory to neurophysiological recordings can discriminate between different brain states, they are limited in directly quantifying the degree of similarity or encoded information between brain responses. Here, we propose a method grounded in algorithmic information theory that affords direct statements about responses' similarity by estimating the encoded information through a compression-based scheme. We validated this method by applying it to both synthetic and real neurophysiological data and compared its efficiency to the mutual information measure. This proposed procedure is especially suited for task paradigms contrasting different event types because it can precisely quantify the similarity of neuronal responses.

• Hatlestad-Hall, Christoffer; Bru?a, Ricardo; Erichsen, Erik Aksel Spendrup; Andersson, Vebj?rn; Syvertsen, Marte Roa & Skogan, Annette Holth [Show all 13 contributors for this article] (2021). The organization of functional neurocognitive networks in focal epilepsy correlates with domain-specific cognitive performance. Journal of Neuroscience Research. ISSN 0360-4012. 99(10), p. 2669¨C2687. doi: 10.1002/jnr.24896. Full text in Research Archive Show summary

  Understanding and diagnosing cognitive impairment in epilepsy remains a prominent challenge. New etiological models suggest that cognitive difficulties might not be directly linked to seizure activity, but are rather a manifestation of a broader brain pathology. Consequently, treating seizures is not sufficient to alleviate cognitive symptoms, highlighting the need for novel diagnostic tools. Here, we investigated whether the organization of three intrinsic, resting-state functional connectivity networks was correlated with domain-specific cognitive test performance. Using individualized EEG source reconstruction and graph theory, we examined the association between network small worldness and cognitive test performance in 23 patients with focal epilepsy and 17 healthy controls, who underwent a series of standardized pencil-and-paper and digital cognitive tests. We observed that the specific networks robustly correlated with test performance in distinct cognitive domains. Specifically, correlations were evident between the default mode network and memory in patients, the central-executive network and executive functioning in controls, and the salience network and social cognition in both groups. Interestingly, the correlations were evident in both groups, but in different domains, suggesting an alteration in these functional neurocognitive networks in focal epilepsy. The present findings highlight the potential clinical relevance of functional brain network dysfunction in cognitive impairment.

• Buades-Rotger, Maci¨¤; Solbakk, Anne-Kristin; Liebrand, Matthias; Endestad, Tor; Funderud, Ingrid & Siegwardt, Paul [Show all 9 contributors for this article] (2021). Patients with ventromedial prefrontal lesions show an implicit approach bias to angry faces. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(6), p. 1069¨C1081. doi: 10.1162/jocn_a_01706. Full text in Research Archive
• Slama, Slama Katarina; Jimenez, Richard; Saha, Sujayam; King-Stephens, David; Laxer, Kenneth D. & Weber, Peter B. [Show all 12 contributors for this article] (2021). Intracranial recordings demonstrate both cortical and medial temporal lobe engagement in visual search in humans. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(9), p. 1833¨C1861. doi: 10.1162/jocn_a_01739. Full text in Research Archive
• Solbakk, Anne-Kristin; Lubell, James; Leske, Sabine; Funderud, Ingrid; Anais, Llorens & Blenkmann, Alejandro Omar [Show all 10 contributors for this article] (2021). Monitoring of self-paced action timing and sensory outcomes after lesions to the orbitofrontal cortex. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(9), p. 1956¨C1975. doi: 10.1162/jocn_a_01733. Full text in Research Archive
• Llorens, Ana?s; Tzovara, Athina; Bellier, Ludovic; Bhaya-Grossman, lIina; Bidet-Caulet, Aurelie & Chang, William K [Show all 45 contributors for this article] (2021). Gender bias in academia: A lifetime problem that needs solutions. Neuron. ISSN 0896-6273. 109(13), p. 2047¨C2074. doi: 10.1016/j.neuron.2021.06.002. Full text in Research Archive
• Liebrand, Matthias; Solbakk, Anne-Kristin; Funderud, Ingrid; Buades-Rotger, Maci¨¤; Knight, Robert Thomas & Kr?mer, Ulrike M (2021). Intact Proactive Motor Inhibition after Unilateral Prefrontal Cortex or Basal Ganglia Lesions. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(9), p. 1862¨C1879. doi: 10.1162/jocn_a_01691. Full text in Research Archive
• Foldal, Maja Dyhre; Blenkmann, Alejandro Omar; Llorens, Ana?s; Knight, Robert T.; Solbakk, Anne-Kristin & Endestad, Tor (2020). The brain tracks auditory rhythm predictability independent of selective attention. Scientific Reports. 10, p. 1¨C13. doi: 10.1038/s41598-020-64758-y. Full text in Research Archive Show summary

  The brain responds to violations of expected rhythms, due to extraction- and prediction of the temporal structure in auditory input. Yet, it is unknown how probability of rhythm violations affects the overall rhythm predictability. Another unresolved question is whether predictive processes are independent of attention processes. In this study, EEG was recorded while subjects listened to rhythmic sequences. Predictability was manipulated by changing the stimulus-onset-asynchrony (SOA deviants) for given tones in the rhythm. When SOA deviants were inserted rarely, predictability remained high, whereas predictability was lower with more frequent SOA deviants. Dichotic tone-presentation allowed for independent manipulation of attention, as specific tones of the rhythm were presented to separate ears. Attention was manipulated by instructing subjects to attend to tones in one ear only, while keeping the rhythmic structure of tones constant. The analyses of event-related potentials revealed an attenuated N1 for tones when rhythm predictability was high, while the N1 was enhanced by attention to tones. Bayesian statistics revealed no interaction between predictability and attention. A right-lateralization of attention effects, but not predictability effects, suggested potentially different cortical processes. This is the first study to show that probability of rhythm violation influences rhythm predictability, independent of attention.

• Llorens, Ana?s; Funderud, Ingrid; Blenkmann, Alejandro Omar; Lubell, James; Foldal, Maja Dyhre & Leske, Sabine Liliana [Show all 11 contributors for this article] (2020). Preservation of Interference Effects in Working Memory After Orbitofrontal Damage. Frontiers in Human Neuroscience. 13, p. 1¨C15. doi: 10.3389/fnhum.2019.00445. Full text in Research Archive Show summary

  Orbitofrontal cortex (OFC) is implicated in multiple cognitive processes, including inhibitory control, context memory, recency judgment, and choice behavior. Despite an emerging understanding of the role of OFC in memory and executive control, its necessity for core working memory (WM) operations remains undefined. Here, we assessed the impact of OFC damage on interference effects in WM using a Recent Probes task based on the Sternberg item-recognition task (1966). Subjects were asked to memorize a set of letters and then indicate whether a probe letter was presented in a particular set. Four conditions were created according to the forthcoming response ("yes"/"no") and the recency of the probe (presented in the previous trial set or not). We compared behavioral and electroencephalography (EEG) responses between healthy subjects (n = 14) and patients with bilateral OFC damage (n = 14). Both groups had the same recency pattern of slower reaction time (RT) when the probe was presented in the previous trial but not in the current one, reflecting the proactive interference (PI). The within-group electrophysiological results showed no condition difference during letter encoding and maintenance. In contrast, event-related potentials (ERPs) to probes showed distinct within-group condition effects, and condition by group effects. The response and recency effects for controls occurred within the same time window (300-500 ms after probe onset) and were observed in two distinct spatial groups including right centro-posterior and left frontal electrodes. Both clusters showed ERP differences elicited by the response effect, and one cluster was also sensitive to the recency manipulation. Condition differences for the OFC group involved two different clusters, encompassing only left hemisphere electrodes and occurring during two consecutive time windows (345-463 ms and 565-710 ms). Both clusters were sensitive to the response effect, but no recency effect was found despite the behavioral recency effect. Although the groups had different electrophysiological responses, the maintenance of letters in WM, the evaluation of the context of the probe, and the decision to accept or reject a probed letter were preserved in OFC patients. The results suggest that neural reorganization may contribute to intact recency judgment and response after OFC damage.

• Kam, Julia W.Y.; Helfrich, Randolph H.; Solbakk, Anne-Kristin; Endestad, Tor; Larsson, P?l Gunnar & Lin, Jack J. [Show all 7 contributors for this article] (2020). Top-Down Attentional Modulation in Human Frontal Cortex: Differential Engagement during External and Internal Attention. Cerebral Cortex. ISSN 1047-3211. 31(2), p. 873¨C883. doi: 10.1093/cercor/bhaa262. Full text in Research Archive Show summary

  Decades of electrophysiological research on top-down control converge on the role of the lateral frontal cortex in facilitating attention to behaviorally relevant external inputs. However, the involvement of frontal cortex in the top-down control of attention directed to the external versus internal environment remains poorly understood. To address this, we recorded intracranial electrocorticography while subjects directed their attention externally to tones and responded to infrequent target tones, or internally to their own thoughts while ignoring the tones. Our analyses focused on frontal and temporal cortices. We first computed the target effect, as indexed by the difference in high frequency activity (70-150 Hz) between target and standard tones. Importantly, we then compared the target effect between external and internal attention, reflecting a top-down attentional effect elicited by task demands, in each region of interest. Both frontal and temporal cortices showed target effects during external and internal attention, suggesting this effect is present irrespective of attention states. However, only the frontal cortex showed an enhanced target effect during external relative to internal attention. These findings provide electrophysiological evidence for top-down attentional modulation in the lateral frontal cortex, revealing preferential engagement with external attention.

• Fjermestad, Krister; Huster, Rene; Thunberg, Christina; Stokke, Simen; Gravholt, Claus H & Solbakk, Anne-Kristin (2020). Neuropsychological functions, sleep, and mental health in adults with Klinefelter syndrome. American Journal of Medical Genetics. Part C, Seminars in Medical Genetics (AJMG). ISSN 1552-4868. 184C, p. 482¨C492. doi: 10.1002/ajmg.c.31797. Full text in Research Archive Show summary

  A few studies have examined neuropsychological functions, sleep, and mental health combined in Klinefelter syndrome (KS; 47,XXY). We investigated neuropsychological functions with standard tests, sleep with actigraphy, and self-reported mental health in 30 men with KS (Mean age = 36.7 years) compared to 21 controls (Mean age = 36.8 years). Men with KS scored significantly lower on mental speed, attention span, working memory, inhibition, and set-shifting tests, as well as overall IQ (mean effect size difference Cohen's d = 0.79). Men with KS had significantly longer night wakes, with no differences in other sleep variables (mean d = 0.34). Men with KS reported poorer mental health than controls (mean d = 1.16). Regression analyses showed neuropsychological functions explained variance in some sleep domains for men with KS but not for controls. Neuropsychological functions explained variance in some mental health domains for controls. For men with KS, however, verbal IQ was the only significant predictor of mental health. Altogether, men with KS display problems in neuropsychological functions and mental health but do not appear different from controls on most sleep parameters. Our findings indicate that relations between neuropsychological functions, sleep, and mental health differ between men with KS and controls.

• Stubberud, Jan; L?vstad, Marianne; Solbakk, Anne-Kristin; Schanke, Anne-Kristine & Torn?s, Sveinung (2020). Emotional regulation following acquired brain injury: Associations with executive functioning in daily life and symptoms of anxiety and depression. Frontiers in Neurology. 11:1011, p. 1¨C7. doi: 10.3389/fneur.2020.01011. Full text in Research Archive Show summary

  Objective: To examine whether a questionnaire measuring emotional regulation after acquired brain injury adds clinical information beyond what can be obtained with a comprehensive executive function questionnaire and an anxiety and depression measure. Method: Seventy adult persons (age 19-66 years, M age = 43, SD age = 13) with acquired brain injury in the chronic phase and executive function complaints. All were recruited to participate in a randomized controlled trial (NCT02692352) evaluating the effects of cognitive rehabilitation. Traumatic brain injury was the dominant cause of injury (64%), and mean time since injury was 8 years. Emotional regulation was assessed with the Brain Injury Trust Regulation of Emotions Questionnaire (BREQ). Executive function was assessed with the Behavior Rating Inventory of Executive Function Adult Version (BRIEF-A). The Hopkins Symptom Checklist 25 (HCSL-25) was employed to measure anxiety and depression symptoms. Results: Overall, significant correlations were found between reports of emotional regulation (BREQ) and executive function in daily life (BRIEF-A). Furthermore, our analyses revealed a significant relationship between self-reported scores of emotional regulation (BREQ) and symptoms of anxiety and depression (HSCL-25). Conclusion: The significant associations between the BREQ and most of the other clinical measures indicate that, for patients with acquired brain injury, the BREQ does not add substantial information beyond what can be assessed with the BRIEF-A and the HSCL-25.

• Hough, Denise; Robinson, Jane E.; Bellingham, Michelle; Fleming, Lynne M.; McLaughlin, Mark & Jama, K. [Show all 9 contributors for this article] (2019). Peripubertal GnRH and testosterone co-treatment leads to increased familiarity preferences in male sheep. Psychoneuroendocrinology. ISSN 0306-4530. 108, p. 70¨C77. doi: 10.1016/j.psyneuen.2019.06.008. Full text in Research Archive Show summary

  Chronic gonadotropin-releasing hormone agonist (GnRHa) treatment is effective for the medical suppression of the hypothalamic-pituitary-gonadal axis in situations like central precocious puberty and gender dysphoria. However, its administration during the peripubertal period could influence normal brain development and function because GnRH receptors are expressed in brain regions that regulate emotions, cognition, motivation and memory. This study used an ovine model to determine whether chronic peripubertal GnRHa-treatment affected the developmental shift from preference of familiarity to novelty. Experimental groups included Controls and GnRHa-treated rams. To differentiate between effects of altered GnRH signaling and those associated with the loss of sex steroids, a group was also included that received testosterone replacement as well as GnRHa (GnRHa?+?T). Preference for a novel versus familiar object was assessed during 5-min social isolation at 8, 28 and 46 weeks of age. Approach behavior was measured as interactions with and time spent near the objects, whereas avoidance behavior was measured by time spent in the entrance zone and attempts to escape the arena via the entry point. Emotional reactivity was measured by the number of vocalizations, escape attempts and urinations. As Control and GnRHa-treated rams aged, their approach behaviors showed a shift from preference for familiarity (8 weeks) to novelty (46 weeks). In contrast, relative to the Controls the GnRHa?+?T rams exhibited more approach behaviors towards both objects, at 28 and 46 weeks of age and preferred familiarity at 46 weeks of age. Vocalisation rate was increased in GnRHa treated rams in late puberty (28 weeks) compared to both Control and GnRHa?+?T rams but this effect was not seen in young adulthood (46 weeks). These results suggest that the specific suppression of testosterone during a developmental window in late puberty may reduce emotional reactivity and hamper learning a flexible adjustment to environmental change. The results also suggest that disruption of either endogenous testosterone signalling or a synergistic action between GnRH and testosterone signalling, may delay maturation of cognitive processes (e.g. information processing) that affects the motivation of rams to approach and avoid objects.

• Torn?s, Sveinung; L?vstad, Marianne; Solbakk, Anne-Kristin; Schanke, Anne-Kristine & Stubberud, Jan (2019). Use it or lose it? A 5-year follow-up study of goal management training in patients with acquired brain injury. Journal of the International Neuropsychological Society. ISSN 1355-6177. p. 1¨C6. doi: 10.1017/S1355617719000626. Full text in Research Archive
• Blenkmann, Alejandro Omar; Collavini, Santiago; Lubell, James; Anais, Llorens; Funderud, Ingrid & Ivanovic, Jugoslav [Show all 13 contributors for this article] (2019). Auditory deviance detection in the human insula: An intracranial EEG study. Cortex. ISSN 0010-9452. 121, p. 189¨C200. doi: 10.1016/j.cortex.2019.09.002. Full text in Research Archive Show summary

  The human insula is known to be involved in auditory processing, but knowledge about its precise functional role and the underlying electrophysiology is limited. To assess its role in automatic auditory deviance detection we analyzed the EEG high frequency activity (HFA; 75¨C145 Hz) and ERPs from 90 intracranial insular channels across 16 patients undergoing pre-surgical intracranial monitoring for epilepsy treatment. Subjects passively listened to a stream of standard and deviant tones differing in four physical dimensions: intensity, frequency, location or time. HFA responses to auditory stimuli were found in the short and long gyri, and the anterior, superior, and inferior segments of the circular sulcus of the insular cortex. Only a subset of channels in the inferior segment of the circular sulcus of the insula showed HFA deviance detection responses, i.e., a greater and longer latency response to specific deviants relative to standards. Auditory deviancy processing was also later in the insula when compared with the superior temporal cortex. ERP results were more widespread and supported the HFA insular findings. These results provide evidence that the human insula is engaged during auditory deviance detection.

• Torn?s, Sveinung; Stubberud, Jan; Solbakk, Anne-Kristin; Evans, Jonathan; Schanke, Anne-Kristine & L?vstad, Marianne (2019). Moderators, mediators and nonspecific predictors of outcome after cognitive rehabilitation of executive functions in a randomised controlled trial. Neuropsychological Rehabilitation. ISSN 0960-2011. 29(6), p. 844¨C865. doi: 10.1080/09602011.2017.1338587. Full text in Research Archive
• Kam, Julia W.Y.; Lin, Jack J.; Solbakk, Anne-Kristin; Endestad, Tor; Larsson, P?l Gunnar & Knight, Robert T. (2019). Default network and frontoparietal control network theta connectivity supports internal attention. Nature Human Behaviour. 3(12), p. 1263¨C1270. doi: 10.1038/s41562-019-0717-0. Full text in Research Archive
• Sadaghiani, Sepideh; Dombert, Pascasie L.; L?vstad, Marianne; Funderud, Ingrid; Meling, Torstein Ragnar & Endestad, Tor [Show all 9 contributors for this article] (2019). Lesions to the fronto-parietal network impact alpha-band phase synchrony and cognitive control. Cerebral Cortex. ISSN 1047-3211. 29(10), p. 4143¨C4153. doi: 10.1093/cercor/bhy296. Full text in Research Archive

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• Gamlemoen, P?l Strande; Solbakk, Anne-Kristin; Hjelle, Ole Petter; Foldal, Maja Dyhre & Leske, Sabine Liliana (2025). Blir du ogs? rasende n?r sidemannen prater i mobilen? Det er det gode grunner til. [Internet]. Aftenposten.no. Full text in Research Archive Show summary

  H?y mobilprating ute i det offentlige kan v?re skikkelig plagsomt. Og det er faktisk gode grunner til at hjernen v?r ikke liker det.

• Torgersen, Eivind; Solbakk, Anne-Kristin & Grane, Venke Arntsberg (2025). Utvikler bedre verkt?y for ? fange opp voksne med ADHD. [Internet]. °ÄÃŻʹÚÌåÓý,»Ê¹Ú×ãÇò±È·Ö.no. Full text in Research Archive Show summary

  ADHD hos voksne sl?r ut annerledes enn hos barn. En ny test som avdekker omfanget av tankevandring, kan bidra til mer treffsikre diagnoser.

• St?ver, Isak Elling August; Leske, Sabine Liliana; Solbakk, Anne-Kristin; Forsmo, Maria Cecilie & Grane, Venke Arntsberg (2025). Nevropsykologi i det kliniske forskningsfeltet: Tankevandring hos voksne med ADHD. Full text in Research Archive
• H¨¹benette, Saira Jameela; Solbakk, Anne-Kristin; Danielsen, Anne; Endestad, Tor & Blenkmann, Alejandro Omar (2025). Hearing in motion: Spatial and temporal processing of auditory stimuli. doi: https:/www.dropbox.com/scl/fi/ijya3kj1w1dl2e7vyjo5y/ICAC25-poster.pdf?rlkey=2516eohjz9vyx3g7qj7rjsedc&st=wm335i35&dl=0. Full text in Research Archive Show summary

  Tracking a moving sound in space requires continuous prediction of its next location. This implies that we must combine information about the time and location of the sound, to accurately predict its trajectory. Using EEG, auditory motion processing has previously been found in frontal, central, and parietal areas of the brain. Prior studies have suggested that space and time for auditory stimuli are processed separately in the brain. Despite the seemingly distinct processing pathways of spatial and temporal sound information, they must integrate at some stage to enable the prediction of movement. It remains unknown if these processes are initially working in parallel and then converging at some point, or if there are several instances of convergence throughout. The goal of this study was to delineate the neural correlates of spatial and temporal processing of moving sounds, and to assess how and when they converge to aid in the tracking of the sound movement.

• Carvalho, Vin¨ªcius Rezende; Collavini, Santiago; Nasimbera, Alejandro; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2025). Single-Neuron Evidence for Attention and Prediction Error to Nested Auditory Regularities in the Human Auditory Cortex. doi: https:/2025.ccneuro.org/abstract_pdf/Carvalho_2025_Single-Neuron_Evidence_Attention_Prediction_Error_.pdf. Full text in Research Archive
• Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Volehaugen, Vegard Akselsson; Carvalho, Vinicius Rezende; Kochen, Silvia & Endestad, Tor [Show all 10 contributors for this article] (2025). Intracranial high-frequency activity and oscillatory cortical dynamics of auditory prediction error propagation in humans. doi: https:/www.maastrichtuniversity.nl/file/icac2025abstracts-2025-09-11pdf. Full text in Research Archive
• Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Volehaugen, Vegard Akselsson; Carvalho, Vinicius Rezende; Kochen, Silvia & Endestad, Tor [Show all 8 contributors for this article] (2025). Spatiotemporal dynamics of auditory prediction error propagation via intracranial EEG in humans. doi: https:/www.frm2025oslo.no/s/FRM2025_AbstractBook.pdf. Full text in Research Archive
• Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2025). Amygdala Responses to Auditory Prediction Violations: Evidence from Human Single-Neuron Recordings. doi: https:/static1.squarespace.com/static/66795375ff6aa75dff1c9eac/t/685e37792a21147062408469/1751005079975/FRM2025_AbstractBook.pdf. Full text in Research Archive
• Leske, Sabine Liliana; St?ver, Isak Elling August; Solbakk, Anne-Kristin; Endestad, Tor; Kam, Julia & Grane, Venke Arntsberg (2025). Behavioral, electromyographic and electrophysiological indicators of altered deviance detection and mind wandering in adult ADHD. Full text in Research Archive
• Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Lubell, Jamie; Llorens, Ana?s; Larsson, P?l Gunnar & Funderud, Ingrid [Show all 12 contributors for this article] (2025). INTRACRANIAL CORRELATES OF ACTION-BASED AUDITORY PREDICTION ERRORS IN HUMANS. Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Doelling, Keith & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2024). Rhythm-based temporal expectations: Unique contributions of predictability and periodicity. Full text in Research Archive Show summary

  Flexibly adapting to our dynamic surroundings requires anticipating upcoming events and focusing our attention accordingly. Rhythmic patterns of sensory input offer valuable cues for these temporal expectations and facilitate perceptual processing. However, a gap in understanding persists regarding how rhythms outside of periodic structures influence perception. Our study aimed to delineate the distinct roles of predictability and periodicity in rhythm-based expectations. Participants completed a pitch-identification task preceded by different rhythm types: periodic predictable, aperiodic predictable, and aperiodic unpredictable. By manipulating the timing of the target sound, we observed how auditory sensitivity was modulated by the target position in the different rhythm conditions. The results revealed a clear behavioral benefit of predictable rhythms, regardless of their periodicity. Interestingly, we also observed an additional effect of periodicity. While both periodic and aperiodic predictable rhythms improved overall sensitivity, only the periodic rhythm seemed to induce an entrained sensitivity pattern, wherein sensitivity peaked in synchrony with the expected continuation of the rhythm. The recorded event-related brain potentials further supported these findings. The target-evoked P3b, possibly a neural marker of attention allocation, mirrored the sensitivity patterns. This supports our hypothesis that perceptual sensitivity is modulated by temporal attention guided by rhythm-based expectations. Furthermore, the effect of rhythm predictability seems to operate through climbing neural activity (similar to the CNV), reflecting preparation for the target. The effect of periodicity is likely related to more precise temporal expectations and could possibly involve neural entrainment. Our findings suggest that predictability and periodicity influence perception via distinct mechanisms.

• Quiroga-Martinez, David R.; Blenkmann, Alejandro O.; Endestad, Tor; Solbakk, Anne-Kristin; Kim-McManus, Olivia & Willie, John T. [Show all 10 contributors for this article] (2024). Enhanced frontotemporal theta and alpha connectivity during the mental manipulation of musical sounds. Full text in Research Archive
• Blenkmann, Alejandro Omar; Volehaugen, Vegard Akselsson; Carvalho, Vinicius Rezende; Leske, Sabine Liliana; Llorens, Anais & Funderud, Ingrid [Show all 14 contributors for this article] (2024). An intracranial EEG study on auditory deviance detection. Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Doelling, Keith & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2024). Rhythm-based temporal expectations: Unique contributions of predictability and periodicity. Full text in Research Archive
• Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2024). Human single-neuron responses to a local-global oddball paradigm. Full text in Research Archive
• Solbakk, Anne-Kristin (2024). Inhibitory control and impulsive actions in ADHD. Full text in Research Archive
• Asko, Olgerta; Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingrid; Llorens, Ana?s & Ivanovic, Jugoslav [Show all 12 contributors for this article] (2024). Predictive encoding of deviant tone sequences in the human prefrontal cortex. Full text in Research Archive
• Asko, Olgerta; Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingrid; Anais, Llorens & Ivanovic, Jugoslav [Show all 12 contributors for this article] (2024). Predictive encoding of deviant tone sequences in the human prefrontal cortex. Full text in Research Archive Show summary

  The ability to use predictive information to guide perception and action relies heavily on the prefrontal cortex (PFC), yet the involvement of its subregions in predictive processes remains unclear. Recent perspectives propose that the orbitofrontal cortex (OFC) generates predictions about perceptual events, actions, and their outcomes while the lateral prefrontal cortex (LPFC) is involved in prospective functions, which support predictive processes, such as selective attention, working memory, response preparation or inhibition. To further delineate the roles of these PFC areas in predictive processing, we investigated whether lesions would impair the ability to build predictions of future events and detect deviations from expected regularities. We used an auditory deviance detection task, in which the structural regularities of played tones were controlled at two hierarchical levels by rules defined at a local (i.e., between tones within sequences) and global (i.e., between sequences) level. We have recently shown that OFC lesions affect detecting prediction violations at two hierarchical levels of rule abstraction, i.e., altered MMN and P3a to local and simultaneous local + global prediction violations (https://doi.org/10.7554/eLife.86386). Now, we focus on the task's predictive aspect and present the latest results showing the involvement of PFC subregions in anticipation of deviances informed by implicit predictive information. Behavioral data shows that deviance expectancy induced faster deviance detection in healthy adults (n=22), suggesting that participants track a state space representation of the task and anticipate upcoming deviant sequences. The analysis of EEG data from patients with focal lesions to the OFC (n = 12) or LPFC (n = 10), and SEEG from the same areas in patients with epilepsy (n = 7), revealed interesting differences. Healthy adults (n = 15) showed modulations of the Contingent Negative Variation (CNV) ¨C a marker of anticipatory activity - tracking the expectancy of deviant tone sequences. However, patients with OFC lesions lacked CNV sensitivity to the predictive context, while patients with LPFC lesions showed moderate sensitivity compared to healthy adults. These results were further supported by intracranial recordings, which revealed expectancy modulation of the high-frequency broadband signal from electrodes in OFC and LPFC, with an earlier latency of activity modulation for the OFC and a later one for the LPFC. Altogether, the complementary approach from behavioral, intracerebral EEG, scalp EEG, and causal lesion data provides compelling evidence for the distinct engagement of the two prefrontal areas in predicting future events and signaling deviations.

• Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Llorens, Ana?s; Lin, Jack J.; Chang, Edward & Brunner, Peter [Show all 12 contributors for this article] (2024). Novel tools for the anatomical registration of intracranial electrodes. Full text in Research Archive
• Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2024). Single-neuron responses to a multifeature oddball paradigm. Full text in Research Archive
• Solbakk, Anne-Kristin; Hope, Mikael; Solli, Sandra; Leske, Sabine Liliana; Foldal, Maja Dyhre & Blenkmann, Alejandro Omar (2024). Research seminar. Full text in Research Archive
• Grane, Venke Arntsberg; Endestad, Tor; St?ver, Isak Elling August; Leske, Sabine Liliana & Solbakk, Anne-Kristin (2024). Executive Function in a Treatment-Naive ADHD Cohort Diagnosed in Adulthood. Full text in Research Archive Show summary

  Background: Attention Deficit Hyperactivity Disorder (ADHD) is an early onset neurodevelopmental condition presenting with diverse cognitive/behavioral impairments that persist into adulthood for half of those affected. Objective: To examine whether unmedicated adults show general- or specific reductions in core executive functions (EFs). Method: Performance on EF-tasks was assessed in adult patients with ADHD, Combined type (n=36) and in healthy controls (n=34), matched on gender, age, and education level. The tasks tapped memory span/working memory (Digit Span), interference control/response inhibition (Color Word Interference Test; CWIT-Inhibition), set-shifting/switching (CWIT-Switching; Trail Making Test [TMT]), and abstract reasoning (Wisconsin Card Sorting Test; [WCST]). Results: There was no group difference in immediate memory span, but the patients performed significantly worse than controls when there was an additional demand on working memory. Statistically controlling for individual differences in information processing speed (using an independent reaction time measure) did not alter the result. Patients performed inferiorly on basic psychomotor speed conditions of the TMT, but the most pronounced group difference appeared on the set-shifting condition. The CWIT-Inhibition condition did not distinguish the groups, but patients had a near-significant tendency to perform more poorly when a concurrent demand on rapid set-switching was introduced. They completed fewer card-sorting categories on the WCST than controls, with more errors overall. There was no significant difference in perseverative errors, but patients committed more non- perseverative errors and failures to maintain set, indicating more random choices and/or losing track of the current sorting principle. Conclusion: ADHD-related reductions of attention maintenance, switching, and working memory, but not inhibitory control, support the literature indicating that ADHD in adulthood is neither associated with specific deficits in inhibitory control, and nor with a general executive impairment. Accordingly, clinical assessment should span a range of EF tests, including the core control functions studied here.

• Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingerid; Carvalho, Vinicius Rezende; Endestad, Tor & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2024). Unheard Surprises: Attention-Dependent Neocortical Dynamics Following Unexpected Omissions Revealed by Intracranial EEG. Full text in Research Archive
• Solbakk, Anne-Kristin & Jensenius, Alexander Refsum (2024). Research Ethics and Legal Perspectives. Full text in Research Archive
• Leske, Sabine Liliana; Endestad, Tor; Volehaugen, Vegard Akselsson; Foldal, Maja Dyhre; Blenkmann, Alejandro Omar & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2024). Predicting the Beat Bin: Beta Oscillations Predict the Envelope Sharpness in a Rhythmic Sequence. Full text in Research Archive
• Leske, Sabine Liliana; St?ver, Isak Elling August; Solbakk, Anne-Kristin; Endestad, Tor; Kam, Julia & Grane, Venke Arntsberg (2024). Behavioral and Electrophysiological Markers of Altered Mind Wandering and Sustained Attention in Adult ADHD. Full text in Research Archive Show summary

  Background: Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that often persists into adulthood. Difficulties with executive control and sustained attention are key characteristics of the disorder that often lead to thoughts that are unrelated to the current task, i.e., mind wandering. Objective: Investigate behavioral and neurophysiological correlates of sustained attention and mind wandering in adults with ADHD not on medication when examined. Method: Sustained attention and propensity to mind-wander was investigated in ADHD patients (n=17) and in healthy controls (n=17), matched on gender, age, and IQ. Participants performed an auditory oddball task (participant feedback: On or Off Task), which required continuous manual responses to standard and target tones, while Electroencephalography (EEG) was measured. Sustained attentional control was additionally examined with the Test of Variables of Attention (T.O.V.A.). General IQ was estimated with a reduced version of the Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV). Results: ADHD patients reported significantly more episodes of mind wandering (Off Task), exhibited reduced target detection accuracy and more Off Task impulsive responses compared to controls. Patients showed a significantly reduced P300 for the target-standard difference components, for both On and Off Task conditions. This target-standard P300 difference was less modulated between On versus Off Task conditions in patients compared to controls. In the T.O.V.A. test, patients committed significantly more Commission Errors, but did not differ from controls on other variables (Attention Comparison score, Reaction Time variability and latency, Omission Errors). Conclusion: In comparison to controls, patients showed deteriorated behavioral performance, more episodes of mind wandering, and reduced P300 in a sustained attention task. The P300 decrease likely reflects impaired control of attentional resources allocated to the task, which has an impact on high-level cognitive processing abilities, while early sensory-related stimulus processing is intact.

• Solbakk, Anne-Kristin; Endestad, Tor; B¨¦gel, Valentin & C?t¨¦-Allard, Ulysse Teller Masao (2024). Novel approaches for unraveling biological and behavioral rhythms in human development. Full text in Research Archive
• Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Llorens, Anais; Lin, Jack J.; Chang, Edward & Brunner, Peter [Show all 12 contributors for this article] (2024). Anatomical registration of intracranial electrodes. Full text in Research Archive
• Asko, Olgerta; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Meling, Torstein Ragnar; Knight, Robert T. & Endestad, Tor [Show all 7 contributors for this article] (2023). The orbitofrontal cortex (OFC) has a critical role in the generation of high-level expectations. Full text in Research Archive
• Leske, Sabine Liliana; Endestad, Tor; Volehaugen, Vegard; Foldal, Maja Dyhre; Blenkmann, Alejandro Omar & Solbakk, Anne-Kristin [Show all 7 contributors for this article] (2023). Predicting the Beat Bin ¨C Beta Oscillations Support Top-Down Prediction of The Temporal Precision of a Beat. Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin & Endestad, Tor (2023). Periodic vs Aperiodic Temporal Predictions: Shared or Separate Mechanisms? Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Solbakk, Anne-Kristin & Endestad, Tor (2023). Periodic vs Aperiodic Temporal Predictions: Shared or Separate Mechanisms? Full text in Research Archive
• Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin & Endestad, Tor (2023). Both periodic and aperiodic rhythms facilitate perceptual processing. Full text in Research Archive
• Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2023). Single-neuron responses to a multifeature oddball paradigm. Full text in Research Archive
• Blenkmann, Alejandro Omar; Asko, Olgerta; Volehaugen, Vegard; Foldal, Maja Dyhre; Solli, Sandra & Leske, Sabine Liliana [Show all 9 contributors for this article] (2023). Auditory perception, memory, and predictions. Full text in Research Archive
• Solbakk, Anne-Kristin; Blenkmann, Alejandro Omar; Leske, Sabine Liliana & Endestad, Tor (2023). Orbitofrontal lesion impacts formation of auditory expectations. Full text in Research Archive
• Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Llorens, Ana?s; Funderud, Ingrid & Larsson, P?l Gunnar [Show all 10 contributors for this article] (2023). Temporal and precentral brain activity in automatic auditory deviance detection. Evidence from human intracranial EEG recordings. Full text in Research Archive
• Volehaugen, Vegard; Leske, Sabine Liliana; Funderud, Ingrid; Llorens, Ana?s; Carvalho, Vinicius Rezende & Endestad, Tor [Show all 8 contributors for this article] (2023). Echoes of the unheard: An intracranial electrophysiology study of expectation and attention in auditory omission processing. Full text in Research Archive
• Asko, Olgerta; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Meling, Torstein Ragnar; Knight, Robert T. & Endestad, Tor [Show all 7 contributors for this article] (2023). Orbitofrontal lesion impacts formation of auditory expectations. Full text in Research Archive Show summary

  Current findings of orbitofrontal cortex (OFC) function suggest that this region might have a role in the generation of prediction error signals associated with top-down expectation of upcoming stimuli. We investigated the impact of lesions to the OFC on the Contingent Negative Variation (CNV), an electrophysiological marker of cognitive expectation and time perception. Twelve OFC patients and fifteen healthy controls performed an auditory local-global paradigm while brain electrical activity was recorded. The structural regularities of the tones were controlled at two hierarchical levels by rules defined at a local (i.e., between tones within sequences) level with a short timescale and at a global (i.e., between sequences) level with a longer timescale. At the global level, deviant tone sequences were interspersed among standard tone sequences in a pseudorandom order, rendering some deviant sequences more anticipated than others. We found that healthy controls exhibited CNV build-up before the occurrence of deviant sequences. The CNV drift rate was modulated by the expectancy of deviant sequences (i.e., the higher the expectancy, the higher the CNV drift rate), reflecting their ability to anticipate when a deviant tone sequence would occur. However, patients with OFC lesions did not show CNV drift modulations by the expectancy of the deviant tone sequences, indicating impaired anticipation of these upcoming events. These findings suggest involvement of the OFC in generating auditory expectations based on the contextual and temporal structure of the task.

• Volehaugen, Vegard; Leske, Sabine Liliana; Endestad, Tor; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar (2022). Violation of rule-based auditory patterns is detected independently of attention. Full text in Research Archive
• Puszta, Andr¨¢s; Solbakk, Anne-Kristin; Huster, Rene J¨¹rgen; Endestad, Tor; Forsmo, Maria & Holmen, Ingrid [Show all 11 contributors for this article] (2022). Interactions between external and internal attention processes during working memory. Full text in Research Archive
• Fuhrer, Julian; Glette, Kyrre; Ivanovic, Jugoslav; Larsson, P?l Gunnar; Bekinschtein, Tristan & Kochen, Silvia [Show all 11 contributors for this article] (2022). Direct brain recordings reveal continuous encoding of structure in random stimuli. Full text in Research Archive
• Fuhrer, Julian; Blenkmann, Alejandro Omar; Endestad, Tor; Solbakk, Anne-Kristin & Glette, Kyrre (2022). Complexity-Based Encoded Information Quantification in Neurophysiological Recordings. Full text in Research Archive
• Asko, Olgerta; Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Foldal, Maja Dyhre; Llorens, Ana?s & Funderud, Ingrid [Show all 10 contributors for this article] (2022). Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex. Full text in Research Archive Show summary

  In this study, we tested the causal involvement of the OFC in noticing breaches of predictions (i.e., PEs) at different hierarchical levels of task structural complexity. With this aim, we examined the event-related potentials (ERPs) of patients with focal OFC lesions and healthy adults while performing an auditory local-global oddball paradigm. Altogether, we found that after OFC damage, low-level PEs (i.e., processing of stimuli that are unpredicted at the local level) and combined low- and high-level PEs (i.e., processing of stimuli that are unpredicted at both the local and global level) were impacted. However, the processing of standard tones was not affected. We conclude that the OFC may contribute to a top-down process that modulates the deviance detection system in the primary auditory cortices, and may be involved in connecting PEs at lower hierarchical areas with predictions at higher areas. The study sheds new light on the poorly explored deficits of hierarchical auditory prediction in patients with damaged OFC.

• Blenkmann, Alejandro Omar; Fuhrer, Julian; Glette, Kyrre; Ivanovic, Jugoslav; Larsson, P?l Gunnar & Bekinschtein, Tristan [Show all 11 contributors for this article] (2022). Direct brain recordings reveal continuous encoding of structure in random stimuli. Full text in Research Archive
• Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Llorens, Ana?s; Funderud, Ingrid & Collavini, Santiago [Show all 13 contributors for this article] (2022). Human brain network involved in auditory deviance detection. An intracranial EEG study. Full text in Research Archive
• Solbakk, Anne-Kristin; Endestad, Tor & Knight, Robert Thomas (2022). Oslo - Berkeley collaboration in cognitive neuroscience and neuropsychology. Full text in Research Archive
• Levine, Brian; Rosenbaum, R. Shayna; Solbakk, Anne-Kristin & D¡¯esposito, Mark (2021). Introduction to the special issue. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(9), p. 1635¨C1635. doi: 10.1162/jocn_e_01754. Full text in Research Archive
• Levine, Brian; Rosenbaum, Shayna; Solbakk, Anne-Kristin & D'Esposito, Mark (2021). Introduction to the special issue. Journal of Cognitive Neuroscience. ISSN 0898-929X. 33(9), p. 1635¨C1635. doi: 10.1162/jocn_e_01754. Full text in Research Archive
• Funderud, Ingrid; Danielsen, Anne; Endestad, Tor; Jensenius, Alexander Refsum; Leske, Sabine Liliana & Solbakk, Anne-Kristin (2021). Improving working memory in patents with epilepsy by rhythmic sounds. Full text in Research Archive
• Puszta, Andras; Huster, Rene J¨¹rgen; Solbakk, Anne-Kristin; Funderud, Ingrid; Endestad, Tor & Grane, Venke Arntsberg (2021). Task-dependent EEG changes in adult ADHD. Full text in Research Archive Show summary

  Objectives Our aim for the current study was twofold: First, delineate how brain connectivity differs between the on-task state during a Go-NoGo task and resting state, and whether these differences are affected by ADHD. Second, we investigated how ADHD impacts event-related potentials and brain oscillations during response inhibition. While the former aim was investigated in an exploratory manner, for the second aim our hypothesis was that P300 amplitude and theta power are decreased in ADHD. Methods We analysed EEG-datasets of 35 adult ADHD patients and a matched healthy control group. EEG was recorded while participants performed a Go-NoGo task and during resting-state. We investigated gamma phase connectivity in the task- and resting state across groups. For the Go-NoGo task, we analysed P300 peak amplitude and latency as well as theta power across conditions and groups. Furthermore, we compared behavioral performance between groups, and evaluated within-group correlations of behavior and EEG parameters. Results We observed a significant main effect of Group for gamma phase connectivity, reflecting increased connectivity in the ADHD- compared to control-group during the task state . We also observed more commission errors in the ADHD-group. NoGo-P300 amplitudes were attenuated and peaked earlier (only over frontal leads) in ADHD patients. Moreover, there was a significant negative correlation between reaction time and both frontal theta power and Go- P300 amplitude in the healthy control but not the ADHD-group. Conclusions Overall, we replicated the ERP-changes reported in earlier studies and behavioral signs of increased impulsivity. The results indicate that ADHD impacts neural indices of response inhibition, but (at least in the ADHD cohort) the neural indices did not not correlate with performance. Furthermore, our results suggest that frontal gamma-band phase connectivity during task state could be a possible neural marker of ADHD.

• Foldal, Maja Dyhre; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Endestad, Tor & Solbakk, Anne-Kristin (2021). Attentional modulation of alpha- and beta oscillations during perception of auditory rhythms. Full text in Research Archive
• Solbakk, Anne-Kristin; Leske, Sabine Liliana; Lubell, James Isaac; Blenkmann, Alejandro Omar; Llorens, Anais & Funderud, Ingrid [Show all 13 contributors for this article] (2021). Auditory prediction and prediction error in self-generated tones. Full text in Research Archive
• Puszta, Andras; Solbakk, Anne-Kristin; Endestad, Tor; Huster, Rene & Grane, Venke Arntsberg (2020). Reduced frontal theta during proactive control in adult ADHD. Full text in Research Archive Show summary

  Previous studies report increased frontal theta activity at rest in individuals with attention deficit-hyperactivity disorder (ADHD). Only few studies investigated task-related frontal theta dynamics in the ADHD population during proactive control. We analysed EEG-datasets recorded from 35 medication-naive adults with ADHD and 32 matched controls performing a cued Go-NoGo-task. The first stimulus(S1, cue) indicated whether the second stimulus would be a Go-stimulus(50% of S1, relevant cue); of these task-relevant trials, the second stimulus(S2) could be a Go or NoGo-signal(equal probability). Normalized theta-power of each trial between 200 and 500 ms after stimulus onset (relative to both S1 and S2) was used for further analysis. We also tested the correlation between frontal-theta-power and behavioural performance. We found that frontal theta power after relevant cues (S1) was elevated in the control group, but not in the ADHD-group. Following the S2-stimuli, theta power was higher after NoGo than Go-stimuli, but there was no significant group-difference. Furthermore, we found significant group-differences regarding the correlation between frontal theta-power after the cue(S1) and the behavioural measures (accuracy, reaction time(RT)) across groups: Theta-power correlated negatively with RT and positively with accuracy in both groups, but these correlations were weaker for the ADHD-group. RT and accuracy were not different across the two groups. Our results indicate a lack of increased frontal theta power to the relevant cues in the ADHD-group, which suggests reduced cognitive effort or a deficit in preparatory attention. Correlation analyses further support the behavioral relevance of these changes in frontal theta dynamics.

• Leske, Sabine Liliana; Lubell, James; Blenkmann, Alejandro Omar; Llorens, Ana?s; Funderud, Ingrid & Foldal, Maja Dyhre [Show all 13 contributors for this article] (2019). Action-based auditory predictions. Full text in Research Archive Show summary

  Sensory consequences of actions are predicted by the brain via an internal forward model to prepare sensory cortical areas, referred to as motor prediction. In a similar vein, the predictive coding framework suggests that perception is based on internal models making predictions about sensory events, based on statistical probabilities of the stimuli. In the current study we investigated action-based sensory predictions. We used a self-paced, two-choice random generation task, infrequently inducing deviant outcomes of voluntary action. Participants repeatedly pressed a right and a left button normatively associated with a 70 ms long 1 kHz and 2 kHz tone, respectively. Occasional deviants occurred, inverting the learned button-tone association. Participants were instructed that their button presses should be random, at a regular but self-paced tempo of one press per 1-2 s, and that they should press both buttons with equal probability. They were informed that the tones are task-irrelevant. We used intracranial EEG (iEEG) data recorded from 10 adult patients with electrodes localized in frontal and temporal lobes. The patients had drug resistant epilepsy and were undergoing presurgical monitoring via implanted stereotactic electrodes. Electrode coordinates and anatomical labels were obtained from coregistered MRI and CT images using iElectrodes toolbox. Initial results indicate that violations of action intentions modulated high frequency band activity (HFA, 75-145 Hz) in distributed brain regions including temporal and prefrontal cortices.

• Leske, Sabine Liliana; Lubell, James Isaac; Blenkmann, Alejandro Omar; Llorens, Ana?s; Funderud, Ingrid & Foldal, Maja Dyhre [Show all 13 contributors for this article] (2019). Auditory prediction and prediction error in self-generated tones. Full text in Research Archive
• Funderud, Ingrid & Solbakk, Anne-Kristin (2019). Event Related Potentials and their functional relevance and Experimental design issues in ERP studies. Full text in Research Archive
• Foldal, Maja Dyhre; Blenkmann, Alejandro Omar; Llorens, Ana?s; Knight, Robert Thomas; Solbakk, Anne-Kristin & Endestad, Tor (2019). The brain tracks global temporal regularity in auditory patterns. Full text in Research Archive
• Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Lubell, James; Leske, Sabine Liliana; Llorens, Ana?s & Funderud, Ingrid [Show all 14 contributors for this article] (2019). Human brain network involved in auditory deviance detection: Evidence from intracranial EEG recordings. Full text in Research Archive Show summary

  The neural network underlying human auditory deviance detection is not fully understood. To address this, we recorded intracranial EEG from 22 adult patients with drug resistant epilepsy undergoing presurgical monitoring who had depth electrodes implanted in all brain lobes (1193 channels in total). Patients passively heard a stream of bilaterally presented tones while reading. We used the Optimum-1 paradigm, that consisted of 300 standard tones interleaved with 300 randomly presented deviant tones per block. Patients completed between 3 to 10 blocks. Deviant tones differed from standards in: 1) intensity (louder or softer), 2) frequency (higher or lower), 3) sound source location (right or left), 4) a shorter duration, or 5) a silent gap in the middle of the tone (N??t?nen et al., 2004). Electrode coordinates were obtained from coregistered MRI and CT images using iElectrodes toolbox (Blenkmann et al., 2017). Channels were bipolar referenced and high frequency band activity (HFA) analytic amplitude signal was obtained using the Hilbert transform (75-145 Hz). Compared to the baseline period, significant HFA responses to tones in general were observed in 31% of the channels. We used an ANOVA to quantify the HFA response variance across trials that could be explained by the different factors of the stimuli: Intensity, Laterality, Frequency, Duration and Gap. We estimated the amount of explained variance by using ?2 (Siegel et al., 2015). Eighteen % of the channels showed a significant increase of the condition-specific explained variance. Some channels showed condition-specific activations to one particular deviant, while others showed activations to a combination of two or more deviants. The channels showing responses to tones in general and condition-specific effects were mostly observed bilaterally in temporal cortex. Frontal, anterior cingulate, and parietal cortices were also involved to a lesser extent. Our results, in line with the predictive coding framework, reveal that a distributed brain network is involved in auditory processing and deviance detection.

• Endestad, Tor; Solbakk, Anne-Kristin; Ivanovic, Jugoslav; Larsson, P?l Gunnar; Knight, Robert T. & Blenkmann, Alejandro Omar (2019). A robust intracranial electrode localization algorithm. Full text in Research Archive Show summary

  The accurate localization of electrodes in relationship to the brain¡¯s anatomy is the foundation of the spatial resolution of intracranial EEG recordings. However, in ¡°difficult cases¡° the localization needs to be done manually since automatic methods fails, e.g high density arrays up to 3 mm inter-electrode distance, overlapping electrodes, low resolution CT images, or connection cables ovelaying grids. Here, we present a new automatic method that models a flexible array of electrodes and fits it to the artifacts observed in post implantation CT images. We evaluated data from 18 adult patients with drug resistant epilepsy implanted with depth electrodes and/or subdural grids (18 patients, 3261 electrodes). The automatic method was contrasted against manual localization. The main processing steps (Fig. 1 A) were: Thresholding and selection of a cloud of CT voxels containing the electrode artifacts Assembling a model of the grid (depth) array of electrodes Fitting the model to a smooth surface (line) approximation of CT artifacts Fitting the model to the cloud of voxels by minimizing the energy function E = -Ec + Et + Ed Ec was the gaussian weighted spatial correlation between the electrodes and the cloud of voxels. Et penalized the translation of electrodes, and Ed the deformation of a spring grid connecting the electrodes. Automatic localization resulted to be more precise than manual selection, observed as a significant reduction of the inter-electrode distance variance (Fig. 1 B). We provide a robust method for intracranial electrode localization that is applicable to ¡°difficult cases¡± were previous automatic methods fail (Fig. 1 C). The method was implemented in the open-source iElectrodes toolbox and is available to the research community (Blenkmann et al., 2017).

• Foldal, Maja Dyhre; Solbakk, Anne-Kristin & Endestad, Tor (2021). Perceiving temporal structure in auditory stimuli: The role of attention and prediction. Universitetet i Oslo. Full text in Research Archive

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