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Blenkmann, Alejandro Omar
(2025).
iElectrodes Toolbox: Fast, Robust, and Open-Source Localization of Intracranial Electrodes.
doi:
https:/cuttingeeg.org/practicalmeeg2025/bouquet/.
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.
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Blenkmann, Alejandro Omar
(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/.
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.
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Hübenette, 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.
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.
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Blenkmann, Alejandro Omar
(2025).
The role of the Orbitoforontal cortex in building predictions and detecting violations.
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Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Lubell, Jamie; Llorens, Ana?s; Larsson, P?l Gunnar & Funderud, Ingrid
[Vis alle 12 forfattere av denne artikkelen]
(2025).
INTRACRANIAL CORRELATES OF ACTION-BASED AUDITORY PREDICTION ERRORS IN HUMANS.
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Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Doelling, Keith & Solbakk, Anne-Kristin
[Vis alle 7 forfattere av denne artikkelen]
(2024).
Rhythm-based temporal expectations: Unique contributions of predictability and periodicity.
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.
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Carvalho, Vinicius Rezende
(2024).
Da trajetória acadêmica à experiência no exterior (From academic trajectory to experience abroad).
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Blenkmann, Alejandro Omar; Volehaugen, Vegard Akselsson; Carvalho, Vinicius Rezende; Leske, Sabine Liliana; Llorens, Anais & Funderud, Ingrid
[Vis alle 14 forfattere av denne artikkelen]
(2024).
An intracranial EEG study on auditory deviance detection.
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Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Doelling, Keith & Solbakk, Anne-Kristin
[Vis alle 7 forfattere av denne artikkelen]
(2024).
Rhythm-based temporal expectations: Unique contributions of predictability and periodicity.
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Basiński, Krzysztof; Dom?alski, Tomasz & Blenkmann, Alejandro Omar
(2024).
The effect of harmonicity on mismatch negativity responses to different auditory features.
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Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar
(2024).
Human single-neuron responses to a local-global oddball paradigm.
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Asko, Olgerta; Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingrid; Llorens, Ana?s & Ivanovic, Jugoslav
[Vis alle 12 forfattere av denne artikkelen]
(2024).
Predictive encoding of deviant tone sequences in the human prefrontal cortex.
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Asko, Olgerta; Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingrid; Anais, Llorens & Ivanovic, Jugoslav
[Vis alle 12 forfattere av denne artikkelen]
(2024).
Predictive encoding of deviant tone sequences in the human prefrontal cortex.
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.
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Blenkmann, Alejandro Omar
(2024).
Current challenges in human EEG/iEEG/SUA.
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Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Llorens, Ana?s; Lin, Jack J.; Chang, Edward & Brunner, Peter
[Vis alle 12 forfattere av denne artikkelen]
(2024).
Novel tools for the anatomical registration of intracranial electrodes.
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Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar
(2024).
Single-neuron responses to a multifeature oddball paradigm.
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Solbakk, Anne-Kristin; Hope, Mikael; Solli, Sandra; Leske, Sabine Liliana; Foldal, Maja Dyhre & Blenkmann, Alejandro Omar
(2024).
Research seminar.
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Blenkmann, Alejandro Omar
(2024).
The role of the Orbitofrontal Cortex in building predictions and detecting violations.
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Volehaugen, Vegard Akselsson; Leske, Sabine Liliana; Funderud, Ingerid; Carvalho, Vinicius Rezende; Endestad, Tor & Solbakk, Anne-Kristin
[Vis alle 7 forfattere av denne artikkelen]
(2024).
Unheard Surprises: Attention-Dependent Neocortical Dynamics Following Unexpected Omissions Revealed by Intracranial EEG.
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Leske, Sabine Liliana; Endestad, Tor; Volehaugen, Vegard Akselsson; Foldal, Maja Dyhre; Blenkmann, Alejandro Omar & Solbakk, Anne-Kristin
[Vis alle 7 forfattere av denne artikkelen]
(2024).
Predicting the Beat Bin: Beta Oscillations Predict
the Envelope Sharpness in a Rhythmic Sequence.
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Blenkmann, Alejandro Omar
(2024).
Electrophysiological correlates of auditory regularity expectations and violations at short and long temporal scales: Studies in intracranial EEG and prefrontal cortex lesion patients.
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Blenkmann, Alejandro Omar
(2024).
Audiopred Project: Neurophysiological mechanisms of auditory predictions.
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Asko, Olgerta; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Meling, Torstein Ragnar; Knight, Robert T. & Endestad, Tor
[Vis alle 7 forfattere av denne artikkelen]
(2023).
The orbitofrontal cortex (OFC) has a critical role in the generation of high-level expectations.
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Blenkmann, Alejandro Omar & Agrawal, Rahul Omprakash
(2023).
Intracranial Electrode Localization workshop.
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Leske, Sabine Liliana; Endestad, Tor; Volehaugen, Vegard; Foldal, Maja Dyhre; Blenkmann, Alejandro Omar & Solbakk, Anne-Kristin
[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.
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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?
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Blenkmann, Alejandro Omar; Ianni, Pablo & Verdugo, Rodrigo
(2023).
Interview for TV show "Salud en Movimiento", Radio Television Neuquén.
[TV].
Neuquen, Argentina.
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Blenkmann, Alejandro Omar & Puppio, Daniel
(2023).
Interview at "La Ma?ana de la Radio" FM 97.3.
[Radio].
Neuquen, Argentina.
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Carvalho, Vinicius Rezende; Mendes, Eduardo Mazoni; Cash, Sydney & Moraes, Márcio
(2023).
Auditory steady-state responses with stereoelectroencephalography: distribution and relation to seizure onset zone.
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Blenkmann, Alejandro Omar
(2023).
Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex - Quantifying Evoked Responses through Encoded Information.
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Solli, Sandra; Danielsen, Anne; Leske, Sabine Liliana; Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin & Endestad, Tor
(2023).
Both periodic and aperiodic rhythms facilitate
perceptual processing.
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Carvalho, Vinicius Rezende; Collavini, Santiago; Kochen, Silvia; Solbakk, Anne-Kristin & Blenkmann, Alejandro Omar
(2023).
Single-neuron responses to a multifeature oddball paradigm.
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Blenkmann, Alejandro Omar
(2023).
Neurophysiological Mechanisms of Human Auditory Predictions: From population- to single neuron recordings.
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Blenkmann, Alejandro Omar; Asko, Olgerta; Volehaugen, Vegard; Foldal, Maja Dyhre; Solli, Sandra & Leske, Sabine Liliana
[Vis alle 9 forfattere av denne artikkelen]
(2023).
Auditory perception, memory, and predictions.
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Solbakk, Anne-Kristin; Blenkmann, Alejandro Omar; Leske, Sabine Liliana & Endestad, Tor
(2023).
Orbitofrontal lesion impacts formation of auditory expectations.
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Blenkmann, Alejandro Omar
(2023).
Expectation and attention in auditory prediction.
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Blenkmann, Alejandro Omar
(2023).
Neural correlates of auditory predictions using intracranial EEG.
Vis sammendrag
Website https://gumed.edu.pl/76777.html
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Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Llorens, Ana?s; Funderud, Ingrid & Larsson, P?l Gunnar
[Vis alle 10 forfattere av denne artikkelen]
(2023).
Temporal and precentral brain activity in automatic auditory deviance detection. Evidence from human intracranial EEG recordings.
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Volehaugen, Vegard; Leske, Sabine Liliana; Funderud, Ingrid; Llorens, Ana?s; Carvalho, Vinicius Rezende & Endestad, Tor
[Vis alle 8 forfattere av denne artikkelen]
(2023).
Echoes of the unheard: An intracranial electrophysiology study of expectation and attention in auditory omission processing.
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Asko, Olgerta; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Meling, Torstein Ragnar; Knight, Robert T. & Endestad, Tor
[Vis alle 7 forfattere av denne artikkelen]
(2023).
Orbitofrontal lesion impacts formation of auditory expectations.
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.
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Bonetti, Leonardo; Foldal, Maja Dyhre; Leske, Sabine Liliana; Asko, Olgerta; Volehaugen, Vegard Akselsson & Solli, Sandra
[Vis alle 7 forfattere av denne artikkelen]
(2023).
Auditory perception, memory, and predictions.
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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.
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Blenkmann, Alejandro Omar
(2022).
How does the brain process unexpected sounds?
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Leske, Sabine Liliana
(2022).
Phase Amplitude Coupling (PAC).
Vis sammendrag
An introduction to the Phase Amplitude Coupling (PAC) measure and how it is applied to EEG data (example code in MATLAB). The caveats of the measure are covered and which sanity checks might be necessary.
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Leske, Sabine Liliana
(2022).
Inter-Trial Coherence (ITC).
Vis sammendrag
An introduction to the inter-trial coherence measure (ITC) and how it is applied to EEG data (with example code/scripts in MATLAB). Furthermore caveats of the measure are discussed along with it's relation to phase opposition measures.
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Leske, Sabine Liliana
(2022).
Fourier Transform.
Vis sammendrag
An introduction to the Fourier transform and how it is applied to EEG data. The short time fourier transform (STFT) and different measures (phase and amplitude) derived from it are explained.
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Fuhrer, Julian; Glette, Kyrre; Ivanovic, Jugoslav; Larsson, P?l Gunnar; Bekinschtein, Tristan & Kochen, Silvia
[Vis alle 11 forfattere av denne artikkelen]
(2022).
Direct brain recordings reveal continuous encoding of structure in random stimuli.
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Fuhrer, Julian; Blenkmann, Alejandro Omar; Endestad, Tor; Solbakk, Anne-Kristin & Glette, Kyrre
(2022).
Complexity-Based Encoded Information Quantification in Neurophysiological Recordings.
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Asko, Olgerta; Blenkmann, Alejandro Omar; Leske, Sabine Liliana; Foldal, Maja Dyhre; Llorens, Ana?s & Funderud, Ingrid
[Vis alle 10 forfattere av denne artikkelen]
(2022).
Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex.
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.
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Blenkmann, Alejandro Omar; Fuhrer, Julian; Glette, Kyrre; Ivanovic, Jugoslav; Larsson, P?l Gunnar & Bekinschtein, Tristan
[Vis alle 11 forfattere av denne artikkelen]
(2022).
Direct brain recordings reveal continuous encoding of structure in random stimuli.
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Blenkmann, Alejandro Omar; Solbakk, Anne-Kristin; Leske, Sabine Liliana; Llorens, Ana?s; Funderud, Ingrid & Collavini, Santiago
[Vis alle 13 forfattere av denne artikkelen]
(2022).
Human brain network involved in auditory deviance detection. An intracranial EEG study.
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Blenkmann, Alejandro Omar
(2022).
Auditory deviance detection in the human insula. Evidence from intracranial EEG recordings.
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Blenkmann, Alejandro Omar
(2021).
Electrode localization in intracranial EEG.
From simulations to novel electrode localization and brain-shift correction
algorithms.
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Blenkmann, Alejandro Omar
(2021).
Some advances in neuroscience using intracranial EEG recordings.