Alejandro Omar Blenkmann

• Vinicius Rezende Carvalho, Alejandro Hugo Nasimbera, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2026). Human Single-Neuron Responses to Multi-Feature Auditory Deviants: Evidence From Medial Temporal Lobe. European Journal of Neuroscience. ISSN 0953-816X. 63(12). doi: 10.1111/ejn.70573. Fulltekst i vitenarkiv
• Olgerta Asko, Vegard Akselsson Volehaugen, Anaïs Llorens, Ingrid Funderud, Sabine Liliana Leske & Jugoslav Ivanovic [Vis alle 13 forfattere av denne artikkelen] (2025). Predictive encoding of auditory sequences in the human prefrontal cortex. bioRxiv - the preprint server for biology. doi: 10.1101/2025.08.22.671264. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Sabine Liliana Leske, Tor Endestad, Vegard Akselsson Volehaugen, Maja Dyhre Foldal, Alejandro Omar Blenkmann & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2025). Beta oscillations predict the envelope sharpness in a rhythmic beat sequence. Scientific Reports. 15(1). doi: 10.1038/s41598-025-86895-y. Fulltekst i vitenarkiv Vis sammendrag

  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 (15–25 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.

• Julian Fuhrer, Kyrre Glette, Jugoslav Ivanovic, Pål Gunnar Larsson, Tristan Bekinschtein & Silvia Kochen [Vis alle 11 forfattere av denne artikkelen] (2025). Direct brain recordings reveal implicit encoding of structure in random auditory streams. Scientific Reports. 15. doi: 10.1038/s41598-025-98865-5. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Jan Weber, Anne-Kristin Solbakk, Alejandro Omar Blenkmann, Llorens Anais, Ingrid Funderud & Sabine Liliana Leske [Vis alle 11 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Sabine Liliana Leske, Llorens Anais, Jack J. Lin, Edward F. Chang & Peter Brunner [Vis alle 12 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Sandra Solli, Anne Danielsen, Sabine Liliana Leske, Alejandro Omar Blenkmann, Keith Doelling & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2024). Rhythm-based Temporal Expectations: Unique Contributions of Predictability and Periodicity. Journal of Cognitive Neuroscience. ISSN 0898-929X. doi: 10.1162/jocn_a_02261. Fulltekst i vitenarkiv Vis sammendrag

  Anticipating events and focusing attention accordingly are crucial for navigating our dynamic environment. Rhythmic patterns of sensory input offer valuable cues for temporal expectations and facilitate perceptual processing. Rhythm-based temporal expectations may rely on oscillatory entrainment, where neural activity and perceptual sensitivity synchronize with periodic stimuli. However, whether entrainment models can account for aperiodic predictable rhythms remains unclear. Our study aimed to delineate the distinct roles of predictability and periodicity in rhythm-based expectations. Participants performed a pitch-identification task preceded by periodic predictable, aperiodic predictable, or aperiodic unpredictable temporal sequences. By manipulating the temporal position of the target sound, we observed how auditory perceptual performance was modulated by the target position's relative phase relationship to the preceding sequences. Results revealed a significant performance advantage for predictable sequences, both periodic and aperiodic, compared with unpredictable ones. However, only the periodic sequence induced an entrained modulation pattern, with performance peaking in synchrony with the inherent sequence continuation. Event-related brain potentials corroborated these findings. The target-evoked P3b, possibly a neural marker of attention allocation, mirrored the behavioral performance patterns. This supports our hypothesis that temporal attention guided by rhythm-based expectations modulates perceptual performance. Furthermore, the predictive sequences were associated with enhanced target-preceding negativity (akin to the contingent negative variation), indicating enhanced target preparation. The periodic-specific modulation likely reflects more precise temporal expectations, potentially involving neural entrainment and/or more focused attention. Our findings suggest that predictability and periodicity influence perception through distinct mechanisms.

• Olgerta Asko, Alejandro Omar Blenkmann, Sabine Liliana Leske, Maja Dyhre Foldal, Llorens Anais & Ingrid Funderud [Vis alle 10 forfattere av denne artikkelen] (2024). Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex. eLIFE. 13. doi: 10.7554/eLife.86386. Fulltekst i vitenarkiv
• Jan Weber, Gabriela Iwama, Anne-Kristin Solbakk, Alejandro Omar Blenkmann, Pål Gunnar Larsson & Jugoslav Ivanovic [Vis alle 9 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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–relevant 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.

• Llorens Anais, Ludovic Bellier, Alejandro Omar Blenkmann, Jugoslav Ivanovic, Pål Gunnar Larsson & Jack J. Lin [Vis alle 9 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Julian Fuhrer, Kyrre Glette, Llorens Anais, Tor Endestad, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2023). Quantifying evoked responses through information-theoretical measures. Frontiers in Neuroinformatics. 17. doi: 10.3389/fninf.2023.1128866. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Maja Dyhre Foldal, Sabine Liliana Leske, Alejandro Omar Blenkmann, Tor Endestad & Anne-Kristin Solbakk (2022). Attentional modulation of beta-power aligns with the timing of behaviorally relevant rhythmic sounds. Cerebral Cortex. ISSN 1047-3211. 33(5), s. 1876–1894. doi: 10.1093/cercor/bhac179. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Anne-Kristin Solbakk, Jugoslav Ivanovic, Pål Gunnar Larsson, Robert Thomas Knight & Tor Endestad (2022). Modeling intracranial electrodes. A simulation platform for the evaluation of localization algorithms. Frontiers in Neuroinformatics. 16, s. 1–20. doi: 10.3389/fninf.2022.788685. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Julian Fuhrer, Alejandro Omar Blenkmann, Tor Endestad, Anne-Kristin Solbakk & Kyrre Glette (2022). Complexity-based Encoded Information Quantification in Neurophysiological Recordings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). s. 2319–2323. doi: 10.1109/EMBC48229.2022.9871501. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Anne-Kristin Solbakk, James Lubell, Sabine Leske, Ingrid Funderud, Llorens Anais & Alejandro Omar Blenkmann [Vis alle 10 forfattere av denne artikkelen] (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), s. 1956–1975. doi: 10.1162/jocn_a_01733. Fulltekst i vitenarkiv
• Maja Dyhre Foldal, Alejandro Omar Blenkmann, Anaïs Llorens, Robert T. Knight, Anne-Kristin Solbakk & Tor Endestad (2020). The brain tracks auditory rhythm predictability independent of selective attention. Scientific Reports. 10, s. 1–13. doi: 10.1038/s41598-020-64758-y. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Anaïs Llorens, Ingrid Funderud, Alejandro Omar Blenkmann, James Lubell, Maja Dyhre Foldal & Sabine Liliana Leske [Vis alle 11 forfattere av denne artikkelen] (2020). Preservation of Interference Effects in Working Memory After Orbitofrontal Damage. Frontiers in Human Neuroscience. 13, s. 1–15. doi: 10.3389/fnhum.2019.00445. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Hernan Rey, Belen Gori, Fernando Chaure, Santiago Collavini, Alejandro Omar Blenkmann & Pablo Seoane [Vis alle 9 forfattere av denne artikkelen] (2020). Single Neuron Coding of Identity in the Human Hippocampal Formation. Current Biology. ISSN 0960-9822. 30. doi: 10.1016/j.cub.2020.01.035. Fulltekst i vitenarkiv Vis sammendrag

  Experimental findings show the ubiquitous presence of graded responses and tuning curves in the neocortex, particularly in visual areas [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]. Among these, inferotemporal-cortex (IT) neurons respond to complex visual stimuli, but differences in the neurons’ responses can be used to distinguish the stimuli eliciting the responses [8, 9, 16, 17, 18]. The IT projects directly to the medial temporal lobe (MTL) [19], where neurons respond selectively to different pictures of specific persons and even to their written and spoken names [20, 21, 22]. However, it is not clear whether this is done through a graded coding, as in the neocortex, or a truly invariant code, in which the response-eliciting stimuli cannot be distinguished from each other. To address this issue, we recorded single neurons during the repeated presentation of different stimuli (pictures and written and spoken names) corresponding to the same persons. Using statistical tests and a decoding approach, we found that only in a minority of cases can the different pictures of a given person be distinguished from the neurons’ responses and that in a larger proportion of cases, the responses to the pictures were different to the ones to the written and spoken names. We argue that MTL neurons tend to lack a representation of sensory features (particularly within a sensory modality), which can be advantageous for the memory function attributed to this area [23, 24, 25], and that a full representation of memories is given by a combination of mostly invariant coding in the MTL with a representation of sensory features in the neocortex.

• Alejandro Omar Blenkmann, Santiago Collavini, James Lubell, Llorens Anais, Ingrid Funderud & Jugoslav Ivanovic [Vis alle 13 forfattere av denne artikkelen] (2019). Auditory deviance detection in the human insula: An intracranial EEG study. Cortex. ISSN 0010-9452. 121, s. 189–200. doi: 10.1016/j.cortex.2019.09.002. Fulltekst i vitenarkiv Vis sammendrag

  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; 75–145 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.

• Alejandro Omar Blenkmann, Holly N. Phillips, Juan Pablo Princich, James B. Rowe, Tristan Bekinschtein & Carlos Muravchik [Vis alle 7 forfattere av denne artikkelen] (2017). iElectrodes: a comprehensive open-source toolbox for depth and subdural grid electrode localization. Frontiers in Neuroinformatics. 11:14, s. 1–16. doi: 10.3389/fninf.2017.00014. Fulltekst i vitenarkiv Vis sammendrag

  The localization of intracranial electrodes is a fundamental step in the analysis of invasive electroencephalography (EEG) recordings in research and clinical practice. The conclusions reached from the analysis of these recordings rely on the accuracy of electrode localization in relationship to brain anatomy. However, currently available techniques for localizing electrodes from magnetic resonance (MR) and/or computerized tomography (CT) images are time consuming and/or limited to particular electrode types or shapes. Here we present iElectrodes, an open-source toolbox that provides robust and accurate semi-automatic localization of both subdural grids and depth electrodes. Using pre- and post-implantation images, the method takes 2–3 min to localize the coordinates in each electrode array and automatically number the electrodes. The proposed pre-processing pipeline allows one to work in a normalized space and to automatically obtain anatomical labels of the localized electrodes without neuroimaging experts. We validated the method with data from 22 patients implanted with a total of 1,242 electrodes. We show that localization distances were within 0.56 mm of those achieved by experienced manual evaluators. iElectrodes provided additional advantages in terms of robustness (even with severe perioperative cerebral distortions), speed (less than half the operator time compared to expert manual localization), simplicity, utility across multiple electrode types (surface and depth electrodes) and all brain regions.

• Holly Phillips, Alejandro Omar Blenkmann, Laura E Hughes, Silvia Kochen, Tristan Bekinschtein & James Rowe (2016). Convergent evidence for hierarchical prediction networks from human electrocorticography and magnetoencephalography. Cortex. ISSN 0010-9452. doi: 10.1016/j.cortex.2016.05.001. Fulltekst i vitenarkiv
• Holly Phillips, Alejandro Omar Blenkmann, Laura E Hughes, Tristan Bekinschtein & James Rowe (2015). Hierarchical Organization of Frontotemporal Networks for the Prediction of Stimuli across Multiple Dimensions. Journal of Neuroscience. ISSN 0270-6474. doi: 10.1523/JNEUROSCI.5095-14.2015. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Holly Phillips, Juan Pablo Princich, Carlos Muravchik & Silvia Kochen (2014). Grid and depth intracranial electrodes localization in a normalized space using MRI and CT images. International Federation for Medical and Biological Engineering Proceedings. ISSN 1680-0737. doi: 10.1007/978-3-319-13117-7_106. Fulltekst i vitenarkiv
• Santiago Collavini, Alejandro Omar Blenkmann & Silvia Kochen (2014). Effective Connectivity in Epileptogenic Networks. International Federation for Medical and Biological Engineering Proceedings. ISSN 1680-0737. doi: 10.1007/978-3-319-13117-7_174. Fulltekst i vitenarkiv
• Juan Pablo Princich, Demian Wassermann, Facundo Latini, Silvia Oddo, Alejandro Omar Blenkmann & Gustavo Seifer [Vis alle 7 forfattere av denne artikkelen] (2013). Rapid and efficient localization of depth electrodes and cortical labeling using free and open source medical software in epilepsy surgery candidates. Frontiers in Neuroscience. ISSN 1662-4548. doi: 10.3389/fnins.2013.00260. Fulltekst i vitenarkiv
• Florencia Jacobacci, Martin Sapir, Santiago Collavini, Silvia Kochen & Alejandro Omar Blenkmann (2013). Assessing effective connectivity in epileptogenic networks. A model-based simulation approach. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. doi: 10.1088/1742-6596/477/1/012037. Fulltekst i vitenarkiv
• Agustin Ibanez, Juan Cardona, Yamil Vidal Dos Santos, Alejandro Omar Blenkmann, Pia Aravena & María Roca [Vis alle 17 forfattere av denne artikkelen] (2013). Motor-language coupling: Direct evidence from early Parkinson’s disease and intracranial cortical recordings. Cortex. ISSN 0010-9452. 49(4). doi: 10.1016/j.cortex.2012.02.014. Fulltekst i vitenarkiv
• Srivas Chennu, Valdas Noreika, Gueorguiev David, Alejandro Omar Blenkmann, Silvia Kochen & Agustin Ibanez [Vis alle 8 forfattere av denne artikkelen] (2013). Expectation and Attention in Hierarchical Auditory Prediction. Journal of Neuroscience. ISSN 0270-6474. doi: 10.1523/JNEUROSCI.0114-13.2013. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Gustavo Seifer, Juan Pablo Princich, Damian Consalvo, Silvia Kochen & Carlos Muravchik (2012). Association between equivalent current dipole source localization and focal cortical dysplasia in epilepsy patients. Epilepsy Research. ISSN 0920-1211. 98, s. 223–231. doi: 10.1016/j.eplepsyres.2011.09.018. Fulltekst i vitenarkiv
• Agustin Ibanez, Hugo Urquina, Agustin Petroni, Sandra Baez, Micaela Do Nascimiento & Eduar Herrera [Vis alle 17 forfattere av denne artikkelen] (2012). Neural Processing of Emotional Facial and Semantic Expressions in Euthymic Bipolar Disorder (BD) and Its Association with Theory of Mind (ToM). PLOS ONE. doi: 10.1371/journal.pone.0046877. Fulltekst i vitenarkiv
• Juan Pablo Princich, Damian Consalvo, Marcelo Kaufman, Gustavo Seifer, Alejandro Omar Blenkmann & Silvia Kochen (2012). Contribución de las imágenes de resonancia magnética por tensor de difusión al diagnóstico de displasias corticales focales. Revista de neurología (Ed. impresa). ISSN 0210-0010. 54(8). doi: 10.33588/rn.5408.2011659. Fulltekst i vitenarkiv
• Gustavo Seifer, Alejandro Omar Blenkmann, Juan Pablo Princich, Damian Consalvo, Cristina Papayannis & Carlos Muravchik [Vis alle 7 forfattere av denne artikkelen] (2012). Noninvasive Approach to Focal CorticalDysplasias: Clinical, EEG, and Neuroimaging Features. Epilepsy Research and Treatment. ISSN 2090-1348. doi: 10.1155/2012/736784. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Alejandro Omar Blenkmann (2025). iElectrodes Toolbox: Fast, Robust, and Open-Source Localization of Intracranial Electrodes. doi: https:/cuttingeeg.org/practicalmeeg2025/bouquet/. Fulltekst i vitenarkiv Vis sammendrag

  Precise anatomical localization of intracranial electrodes is crucial for interpreting invasive recordings in clinical and cognitive neuroscience research. The open-source iElectrodes toolbox offers a fast, semi-automated, and robust solution for localizing subdural grids, depth electrodes, and strips from MRI and CT images, supporting automatic anatomical labeling. iElectrodes was initially introduced in Blenkmann et al. (2017), and has been updated with major methodological innovations in Blenkmann et al. (2024). To date, it has >2000 downloads. In this 90-minute session, I will first provide an introductory lecture on the core functionalities of iElectrodes, including image pre-processing steps, semi-automatic electrode localization, brain shift compensation, and standardized anatomical registration. We will cover the recent major upgrades to the toolbox: the GridFit algorithm for robust localization of SEEG and ECoG electrodes under challenging conditions (e.g., noise, overlaps, and high-density implants), and CEPA (Combined Electrode Projection Algorithm) for smooth compensation methods for grids, addressing brain deformations based on mechanical modeling principles. These developments significantly enhanced the robustness and precision of intracranial electrode localization. In the second part of the session, we will move into a hands-on tutorial, where participants will learn how to use the toolbox through practical exercises. Using real patient datasets (anonymized), we will cover: • Preprocessing MRI and CT images. • Semi-automatic detection and localization of electrode coordinates using clustering and GridFit algorithms. • Brain shift correction using CEPA. • Automatic anatomical labeling of electrodes. • Generation of an iElectrodes localization project file. • Exporting electrode coordinates into formats compatible with Fieldtrip, EEGLAB, and text reports. • Integration with further analysis workflows. This session is intended for both clinical and cognitive neuroscience research users working with SEEG or ECoG. Attendees will leave with practical skills for reliable and reproducible electrode localization, ready to apply to their own datasets.

• Alejandro Omar Blenkmann (2025). Auditory Prediction and Its Neural Correlates. doi: https:/csan2025.saneurociencias.org.ar/symposia/neurophysiological-bases-of-memory-consciousness-and-interoception-in-humans-from-the-neuron-to-neural-networks/. Fulltekst i vitenarkiv Vis sammendrag

  This panel presents research on the neural mechanisms underlying auditory prediction—a fundamental process for the perception of sound, language, and music. Evidence is presented on how the brain anticipates and processes auditory stimuli through neural networks that integrate prior sensory information, thereby facilitating the interpretation of speech and complex musical structures. Using neurophysiological and neuroimaging studies, researchers have identified the neural correlates of auditory prediction in regions such as the auditory cortex and areas involved in memory and attention. Additionally, computational models are analyzed to explain how the brain dynamically adjusts its expectations in response to variations in auditory stimuli.

• Saira Jameela Hübenette, Anne-Kristin Solbakk, Anne Danielsen, Tor Endestad & Alejandro Omar Blenkmann (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Vinícius Rezende Carvalho, Santiago Collavini, Alejandro Nasimbera, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (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. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2025). The role of the Orbitoforontal cortex in building predictions and detecting violations. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Sabine Liliana Leske, Vegard Akselsson Volehaugen, Vinicius Rezende Carvalho, Silvia Kochen & Tor Endestad [Vis alle 10 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Sabine Liliana Leske, Vegard Akselsson Volehaugen, Vinicius Rezende Carvalho, Silvia Kochen & Tor Endestad [Vis alle 8 forfattere av denne artikkelen] (2025). Spatiotemporal dynamics of auditory prediction error propagation via intracranial EEG in humans. doi: https:/www.frm2025oslo.no/s/FRM2025_AbstractBook.pdf. Fulltekst i vitenarkiv
• Vinicius Rezende Carvalho, Santiago Collavini, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (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. Fulltekst i vitenarkiv
• Sabine Liliana Leske, Alejandro Omar Blenkmann, Jamie Lubell, Anaïs Llorens, Pål Gunnar Larsson & Ingrid Funderud [Vis alle 12 forfattere av denne artikkelen] (2025). INTRACRANIAL CORRELATES OF ACTION-BASED AUDITORY PREDICTION ERRORS IN HUMANS. Fulltekst i vitenarkiv
• Sandra Solli, Anne Danielsen, Sabine Liliana Leske, Alejandro Omar Blenkmann, Keith Doelling & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2024). Rhythm-based temporal expectations: Unique contributions of predictability and periodicity. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Alejandro Omar Blenkmann, Vegard Akselsson Volehaugen, Vinicius Rezende Carvalho, Sabine Liliana Leske, Anais Llorens & Ingrid Funderud [Vis alle 14 forfattere av denne artikkelen] (2024). An intracranial EEG study on auditory deviance detection. Fulltekst i vitenarkiv
• Sandra Solli, Anne Danielsen, Sabine Liliana Leske, Alejandro Omar Blenkmann, Keith Doelling & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2024). Rhythm-based temporal expectations: Unique contributions of predictability and periodicity. Fulltekst i vitenarkiv
• Krzysztof Basiński, Tomasz Domżalski & Alejandro Omar Blenkmann (2024). The effect of harmonicity on mismatch negativity responses to different auditory features. Fulltekst i vitenarkiv
• Vinicius Rezende Carvalho, Santiago Collavini, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2024). Human single-neuron responses to a local-global oddball paradigm. Fulltekst i vitenarkiv
• Olgerta Asko, Vegard Akselsson Volehaugen, Sabine Liliana Leske, Ingrid Funderud, Anaïs Llorens & Jugoslav Ivanovic [Vis alle 12 forfattere av denne artikkelen] (2024). Predictive encoding of deviant tone sequences in the human prefrontal cortex. Fulltekst i vitenarkiv
• Olgerta Asko, Vegard Akselsson Volehaugen, Sabine Liliana Leske, Ingrid Funderud, Llorens Anais & Jugoslav Ivanovic [Vis alle 12 forfattere av denne artikkelen] (2024). Predictive encoding of deviant tone sequences in the human prefrontal cortex. Fulltekst i vitenarkiv Vis sammendrag

  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) – 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.

• Alejandro Omar Blenkmann (2024). Current challenges in human EEG/iEEG/SUA. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Sabine Liliana Leske, Anaïs Llorens, Jack J. Lin, Edward Chang & Peter Brunner [Vis alle 12 forfattere av denne artikkelen] (2024). Novel tools for the anatomical registration of intracranial electrodes. Fulltekst i vitenarkiv
• Vinicius Rezende Carvalho, Santiago Collavini, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2024). Single-neuron responses to a multifeature oddball paradigm. Fulltekst i vitenarkiv
• Anne-Kristin Solbakk, Mikael Hope, Sandra Solli, Sabine Liliana Leske, Maja Dyhre Foldal & Alejandro Omar Blenkmann (2024). Research seminar. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2024). The role of the Orbitofrontal Cortex in building predictions and detecting violations. Fulltekst i vitenarkiv
• Vegard Akselsson Volehaugen, Sabine Liliana Leske, Ingerid Funderud, Vinicius Rezende Carvalho, Tor Endestad & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2024). Unheard Surprises: Attention-Dependent Neocortical Dynamics Following Unexpected Omissions Revealed by Intracranial EEG. Fulltekst i vitenarkiv
• Sabine Liliana Leske, Tor Endestad, Vegard Akselsson Volehaugen, Maja Dyhre Foldal, Alejandro Omar Blenkmann & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2024). Predicting the Beat Bin: Beta Oscillations Predict the Envelope Sharpness in a Rhythmic Sequence. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2024). Electrophysiological correlates of auditory regularity expectations and violations at short and long temporal scales: Studies in intracranial EEG and prefrontal cortex lesion patients. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Sabine Liliana Leske, Anais Llorens, Jack J. Lin, Edward Chang & Peter Brunner [Vis alle 12 forfattere av denne artikkelen] (2024). Anatomical registration of intracranial electrodes. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2024). Audiopred Project: Neurophysiological mechanisms of auditory predictions. Fulltekst i vitenarkiv
• Olgerta Asko, Anne-Kristin Solbakk, Sabine Liliana Leske, Torstein Ragnar Meling, Robert T. Knight & Tor Endestad [Vis alle 7 forfattere av denne artikkelen] (2023). The orbitofrontal cortex (OFC) has a critical role in the generation of high-level expectations. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann & Rahul Omprakash Agrawal (2023). Intracranial Electrode Localization workshop. Fulltekst i vitenarkiv
• Sabine Liliana Leske, Tor Endestad, Vegard Volehaugen, Maja Dyhre Foldal, Alejandro Omar Blenkmann & Anne-Kristin Solbakk [Vis alle 7 forfattere av denne artikkelen] (2023). Predicting the Beat Bin – Beta Oscillations Support Top-Down Prediction of The Temporal Precision of a Beat. Fulltekst i vitenarkiv
• Sandra Solli, Anne Danielsen, Sabine Liliana Leske, Alejandro Omar Blenkmann, Anne-Kristin Solbakk & Tor Endestad (2023). Periodic vs Aperiodic Temporal Predictions: Shared or Separate Mechanisms? Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Pablo Ianni & Rodrigo Verdugo (2023). Interview for TV show "Salud en Movimiento", Radio Television Neuquén. [TV]. Neuquen, Argentina. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann & Daniel Puppio (2023). Interview at "La Mañana de la Radio" FM 97.3. [Radio]. Neuquen, Argentina. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2023). Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex - Quantifying Evoked Responses through Encoded Information. Fulltekst i vitenarkiv
• Sandra Solli, Anne Danielsen, Sabine Liliana Leske, Alejandro Omar Blenkmann, Anne-Kristin Solbakk & Tor Endestad (2023). Both periodic and aperiodic rhythms facilitate perceptual processing. Fulltekst i vitenarkiv
• Vinicius Rezende Carvalho, Santiago Collavini, Silvia Kochen, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2023). Single-neuron responses to a multifeature oddball paradigm. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2023). Neurophysiological Mechanisms of Human Auditory Predictions: From population- to single neuron recordings. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Olgerta Asko, Vegard Volehaugen, Maja Dyhre Foldal, Sandra Solli & Sabine Liliana Leske [Vis alle 9 forfattere av denne artikkelen] (2023). Auditory perception, memory, and predictions. Fulltekst i vitenarkiv
• Anne-Kristin Solbakk, Alejandro Omar Blenkmann, Sabine Liliana Leske & Tor Endestad (2023). Orbitofrontal lesion impacts formation of auditory expectations. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2023). Expectation and attention in auditory prediction. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2023). Neural correlates of auditory predictions using intracranial EEG. Fulltekst i vitenarkiv Vis sammendrag

  Website https://gumed.edu.pl/76777.html

• Alejandro Omar Blenkmann, Anne-Kristin Solbakk, Sabine Liliana Leske, Anaïs Llorens, Ingrid Funderud & Pål Gunnar Larsson [Vis alle 10 forfattere av denne artikkelen] (2023). Temporal and precentral brain activity in automatic auditory deviance detection. Evidence from human intracranial EEG recordings. Fulltekst i vitenarkiv
• Vegard Volehaugen, Sabine Liliana Leske, Ingrid Funderud, Anaïs Llorens, Vinicius Rezende Carvalho & Tor Endestad [Vis alle 8 forfattere av denne artikkelen] (2023). Echoes of the unheard: An intracranial electrophysiology study of expectation and attention in auditory omission processing. Fulltekst i vitenarkiv
• Olgerta Asko, Anne-Kristin Solbakk, Sabine Liliana Leske, Torstein Ragnar Meling, Robert T. Knight & Tor Endestad [Vis alle 7 forfattere av denne artikkelen] (2023). Orbitofrontal lesion impacts formation of auditory expectations. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Leonardo Bonetti, Maja Dyhre Foldal, Sabine Liliana Leske, Olgerta Asko, Vegard Akselsson Volehaugen & Sandra Solli [Vis alle 7 forfattere av denne artikkelen] (2023). Auditory perception, memory, and predictions. Fulltekst i vitenarkiv
• Vegard Volehaugen, Sabine Liliana Leske, Tor Endestad, Anne-Kristin Solbakk & Alejandro Omar Blenkmann (2022). Violation of rule-based auditory patterns is detected independently of attention. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2022). How does the brain process unexpected sounds? Fulltekst i vitenarkiv
• Julian Fuhrer, Kyrre Glette, Jugoslav Ivanovic, Pål Gunnar Larsson, Tristan Bekinschtein & Silvia Kochen [Vis alle 11 forfattere av denne artikkelen] (2022). Direct brain recordings reveal continuous encoding of structure in random stimuli. Fulltekst i vitenarkiv
• Julian Fuhrer, Alejandro Omar Blenkmann, Tor Endestad, Anne-Kristin Solbakk & Kyrre Glette (2022). Complexity-Based Encoded Information Quantification in Neurophysiological Recordings. Fulltekst i vitenarkiv
• Olgerta Asko, Alejandro Omar Blenkmann, Sabine Liliana Leske, Maja Dyhre Foldal, Anaïs Llorens & Ingrid Funderud [Vis alle 10 forfattere av denne artikkelen] (2022). Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Alejandro Omar Blenkmann, Julian Fuhrer, Kyrre Glette, Jugoslav Ivanovic, Pål Gunnar Larsson & Tristan Bekinschtein [Vis alle 11 forfattere av denne artikkelen] (2022). Direct brain recordings reveal continuous encoding of structure in random stimuli. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Anne-Kristin Solbakk, Sabine Liliana Leske, Anaïs Llorens, Ingrid Funderud & Santiago Collavini [Vis alle 13 forfattere av denne artikkelen] (2022). Human brain network involved in auditory deviance detection. An intracranial EEG study. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2022). Auditory deviance detection in the human insula. Evidence from intracranial EEG recordings. Fulltekst i vitenarkiv
• Maja Dyhre Foldal, Sabine Liliana Leske, Alejandro Omar Blenkmann, Tor Endestad & Anne-Kristin Solbakk (2021). Attentional modulation of alpha- and beta oscillations during perception of auditory rhythms. Fulltekst i vitenarkiv
• Anne-Kristin Solbakk, Sabine Liliana Leske, James Isaac Lubell, Alejandro Omar Blenkmann, Anais Llorens & Ingrid Funderud [Vis alle 13 forfattere av denne artikkelen] (2021). Auditory prediction and prediction error in self-generated tones. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2021). Electrode localization in intracranial EEG. From simulations to novel electrode localization and brain-shift correction algorithms. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2021). Some advances in neuroscience using intracranial EEG recordings. Fulltekst i vitenarkiv
• Sabine Liliana Leske, James Lubell, Alejandro Omar Blenkmann, Anaïs Llorens, Ingrid Funderud & Maja Dyhre Foldal [Vis alle 13 forfattere av denne artikkelen] (2019). Action-based auditory predictions. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Sabine Liliana Leske, James Isaac Lubell, Alejandro Omar Blenkmann, Anaïs Llorens, Ingrid Funderud & Maja Dyhre Foldal [Vis alle 13 forfattere av denne artikkelen] (2019). Auditory prediction and prediction error in self-generated tones. Fulltekst i vitenarkiv
• Julian Fuhrer, Alejandro Omar Blenkmann, Jim Tørresen, Tor Endestad & Kyrre Glette (2019). Making Sense of Randomness? Fulltekst i vitenarkiv
• Britta Westner, Lau Møller Andersen, Alejandro Omar Blenkmann & Sabine Liliana Leske (2019). RITMO International EEG FieldTrip workshop, Lectures and Hands-on sessions. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann (2019). Origins of the EEG signal and Technical setup of EEG. Fulltekst i vitenarkiv
• Maja Dyhre Foldal, Alejandro Omar Blenkmann, Anaïs Llorens, Robert Thomas Knight, Anne-Kristin Solbakk & Tor Endestad (2019). The brain tracks global temporal regularity in auditory patterns. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, Anne-Kristin Solbakk, James Lubell, Sabine Liliana Leske, Anaïs Llorens & Ingrid Funderud [Vis alle 14 forfattere av denne artikkelen] (2019). Human brain network involved in auditory deviance detection: Evidence from intracranial EEG recordings. Fulltekst i vitenarkiv Vis sammendrag

  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 (Näätänen 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.

• Alejandro Omar Blenkmann (2019). Auditory deviance detection network in the human brain. Fulltekst i vitenarkiv
• Tor Endestad, Anne-Kristin Solbakk, Jugoslav Ivanovic, Pål Gunnar Larsson, Robert T. Knight & Alejandro Omar Blenkmann (2019). A robust intracranial electrode localization algorithm. Fulltekst i vitenarkiv Vis sammendrag

  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).

• Alejandro Omar Blenkmann, Anne-Kristin Solbakk, James Lubell, Sabine Liliana Leske, Anaïs Llorens & Ingrid Funderud [Vis alle 14 forfattere av denne artikkelen] (2019). Human brain network involved in auditory deviance detection: Evidence from intracranial EEG recordings. Fulltekst i vitenarkiv
• Alejandro Omar Blenkmann, James Lubell, Anais Llorens, Ingrid Funderud, Santiago Collavini & PG Larsson [Vis alle 13 forfattere av denne artikkelen] (2018). Human insula response to auditory deviants: Evidence from intracranial EEG recordings. Fulltekst i vitenarkiv
• Agustin Ibanez, Agustin Petroni, Hugo Urquina, Teresa Torralva, Alejandro Omar Blenkmann & Leandro Beltrachini [Vis alle 15 forfattere av denne artikkelen] (2012). Cortical deficits in emotion processing for faces in adults with ADHD: Its relation to social cognition and executive functioning. I Facundo Manes & Mario Mendez (Red.), Social Neuroscience of Psychiatric Disorders. Psychology Press. ISSN 9781848727571. Fulltekst i vitenarkiv

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