Anatomical registration of intracranial electrodes. Robust model-based localization and deformable smooth brain-shift compensation methods

Abstract:

Background: Intracranial electrodes are typically localized from post-implantation CT artifacts. Automatic algorithms localizing low signal-to-noise ratio artifacts and high-density electrode arrays are missing. Additionally, implantation of grids/strips introduces brain deformations, resulting in registration errors when fusing post- implantation CT and pre-implantation MR images. Brain-shift compensation methods project electrode coordinates to cortex, but either fail to produce smooth solutions or do not account for brain deformations. New methods: We first introduce GridFit, a model-based fitting approach that simultaneously localizes all electrodes’ CT artifacts in grids, strips, or depth arrays. Second, we present CEPA, a brain-shift compensation algorithm combining orthogonal-based projections, spring-mesh models, and spatial regularization constraints. Results: We tested GridFit on ~6000 simulated scenarios. The localization of CT artifacts showed robust performance under difficult scenarios, such as noise, overlaps, and high-density implants (<1 mm errors). Validation with data from 20 challenging patients showed 99% accurate localization of the electrodes (3160/3192). We tested CEPA brain-shift compensation with data from 15 patients. Projections accounted for simple mechanical deformation principles with <0.4 mm errors. The inter-electrode distances smoothly changed across neighbor electrodes, while changes in inter-electrode distances linearly increased with projection distance. Comparison with existing methods: GridFit succeeded in difficult scenarios that challenged available methods and outperformed visual localization by preserving the inter-electrode distance. CEPA registration errors were smaller than those obtained for well-established alternatives. Additionally, modeling resting-state high-frequency activity in five patients further supported CEPA.

Authors:

• Alejandro Omar Blenkmann

• Sabine Liliana Leske

• Anaïs Llorens

• Jack J. Lin

• Edward F. Chang

• Peter Brunner

• Gerwin Schalk

• Jugoslav Ivanovic

• Pål Gunnar Larsson

• Robert Thomas Knight

• Tor Endestad

• Anne-Kristin Solbakk

Date: 2024

DOI: https://doi.org/10.1016/j.jneumeth.2024.110056

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Predictable and unpredictable deviance detection in the human hippocampus and amygdala

Abstract:

Our brains extract structure from the environment and form predictions given past experience. Predictive circuits have been identified in wide-spread cortical regions. However, the contribution of medial temporal structures in predictions remains under-explored. The hippocampus underlies sequence detection and is sensitive to novel stimuli, sufficient to gain access to memory, while the amygdala to novelty. Yet, their electrophysiological profiles in detecting predictable and unpredictable deviant auditory events remain unknown. Here, we hypothesized that the hippocampus would be sensitive to predictability, while the amygdala to unexpected deviance. We presented epileptic patients undergoing presurgical monitoring with standard and deviant sounds, in predictable or unpredictable contexts. Onsets of auditory responses and unpredictable deviance effects were detected earlier in the temporal cortex compared with the amygdala and hippocampus. Deviance effects in 1–20 Hz local field potentials were detected in the lateral temporal cortex, irrespective of predictability. The amygdala showed stronger deviance in the unpredictable context. Low-frequency deviance responses in the hippocampus (1–8 Hz) were observed in the predictable but not in the unpredictable context. Our results reveal a distributed network underlying the generation of auditory predictions and suggest that the neural basis of sensory predictions and prediction error signals needs to be extended.

Authors:

• Athina Tzovara

• Tommaso Fedele

• Johannes Sarnthein

• Debora Ledergerber

• Jack J. Lin

• Robert T. Knight

Date: 2024

DOI: https://doi.org/10.1093/cercor/bhad532

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Awake ripples enhance emotional memory encoding in the human brain

Abstract:

Enhanced memory for emotional experiences is hypothesized to depend on amygdala-hippocampal interactions during memory consolidation. Here we show using intracranial recordings from the human amygdala and the hippocampus during an emotional memory encoding and discrimination task increased awake ripples after encoding of emotional, compared to neutrally-valenced stimuli. Further, post-encoding ripple-locked stimulus similarity is predictive of later memory discrimination. Ripple-locked stimulus similarity appears earlier in the amygdala than in hippocampus and mutual information analysis confirms amygdala influence on hippocampal activity. Finally, the joint ripple-locked stimulus similarity in the amygdala and hippocampus is predictive of correct memory discrimination. These findings provide electrophysiological evidence that post-encoding ripples enhance memory for emotional events.

Authors:

• Haoxin Zhang

• Ivan Skelin

• Shiting Ma

• Michelle Paff

• Lilit Mnatsakanyan

• Michael A. Yassa

• Robert T. Knight

• Jack J. Lin

Date: 2024

DOI: https://doi.org/10.1038/s41467-023-44295-8

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Asymmetric coding of reward prediction errors in human insula and dorsomedial prefrontal cortex

Abstract:

The signed value and unsigned salience of reward prediction errors (RPEs) are critical to understanding reinforcement learning (RL) and cognitive control. Dorsomedial prefrontal cortex (dMPFC) and insula (INS) are key regions for integrating reward and surprise information, but conflicting evidence for both signed and unsigned activity has led to multiple proposals for the nature of RPE representations in these brain areas. Recently developed RL models allow neurons to respond differently to positive and negative RPEs. Here, we use intracranially recorded high frequency activity (HFA) to test whether this flexible asymmetric coding strategy captures RPE coding diversity in human INS and dMPFC. At the region level, we found a bias towards positive RPEs in both areas which paralleled behavioral adaptation. At the local level, we found spatially interleaved neural populations responding to unsigned RPE salience and valence-specific positive and negative RPEs. Furthermore, directional connectivity estimates revealed a leading role of INS in communicating positive and unsigned RPEs to dMPFC. These findings support asymmetric coding across distinct but intermingled neural populations as a core principle of RPE processing and inform theories of the role of dMPFC and INS in RL and cognitive control.

Authors:

• Colin W. Hoy

• David R. Quiroga-Martinez

• Eduardo Sandoval

• David King-Stephens

• Kenneth D. Laxer

• Peter Weber

• Jack J. Lin

• Robert T. Knight

Date: 2023

DOI: https://doi.org/10.1038/s41467-023-44248-1

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Decision and response monitoring during working memory are sequentially represented in the human insula

Abstract:

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.

Authors:

• Anaïs Llorens

• Ludovic Bellier

• Alejandro O. Blenkmann

• Jugoslav Ivanovic

• Pål G. Larsson

• Jack J. Lin

• Tor Endestad

• Anne-Kristin Solbakk

• Robert T. Knight

Date: 2023

DOI: https://doi.org/10.1016/j.isci.2023.107653

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Multiple memory systems for efficient temporal order memory

Abstract:

We report distinct contributions of multiple memory systems to the retrieval of the temporal order of events. The neural dynamics related to the retrieval of movie scenes revealed that recalling the temporal order of close events elevates hippocampal theta power, like that observed for recalling close spatial relationships. In contrast, recalling far events increases beta power in the orbitofrontal cortex, reflecting recall based on the overall movie structure.

Authors:

• Anna Jafarpour

• Jack J. Lin

• Robert T. Knight

• Elizabeth A. Buffalo

Date: 2023

DOI: https://doi.org/10.1002/hipo.23550

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Electrophysiological signatures of inequity-dependent reward encoding in the human OFC

Abstract:

Social decision making requires the integration of reward valuation and social cognition systems, both dependent on the orbitofrontal cortex (OFC). How these two OFC functions interact is largely unknown. We recorded intracranial activity from the OFC of ten patients making choices in a social context where reward inequity with a social counterpart varied and could be either advantageous or disadvantageous. We find that OFC high-frequency activity (HFA; 70–150Hz) encodes self-reward, consistent with previous reports. We also observe encoding of the social counterpart’s reward, as well as the type of inequity being experienced. Additionally, we find evidence of inequity-dependent reward encoding: depending on the type of inequity, electrodes rapidly and reversibly switch between different reward-encoding profiles. These results provide direct evidence for encoding of self- and other rewards in the human OFC and highlight the dynamic nature of encoding in the OFC as a function of social context.

Authors:

• Deborah Marciano

• Brooke R. Staveland

• Jack J. Lin

• Ignacio Saez

• Ming Hsu

• Robert T. Knight

Date: 2023

DOI: https://doi.org/10.1016/j.celrep.2023.112865

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Human REM sleep recalibrates neural activity in support of memory formation

Abstract:

The proposed mechanisms of sleep-dependent memory consolidation involve the overnight regulation of neural activity at both synaptic and whole-network levels. Now, there is a lack of in vivo data in humans elucidating if, and how, sleep and its varied stages balance neural activity, and if such recalibration benefits memory. We combined electrophysiology with in vivo two-photon calcium imaging in rodents as well as intracranial and scalp electroencephalography (EEG) in humans to reveal a key role for non-oscillatory brain activity during rapid eye movement (REM) sleep to mediate sleep-dependent recalibration of neural population dynamics. The extent of this REM sleep recalibration predicted the success of overnight memory consolidation, expressly the modulation of hippocampal—neocortical activity, favoring remembering rather than forgetting. The findings describe a non-oscillatory mechanism how human REM sleep modulates neural population activity to enhance long-term memory.

Authors:

• Janna D. Lendner

• Niels Niethard

• Bryce A. Mander

• Frank J. van Schalkwijk

• Sigrid Schuh-Hofer

• Hannah Schmidt

• Robert T. Knight

• Jan Born

• Matthew P. Walker

• Jack J. Lin

• Randolph F. Helfrich

Date: 2023

DOI: DOI: 10.1126/sciadv.adj1895

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A rapid theta network mechanism for flexible information encoding

Abstract:

Flexible behavior requires gating mechanisms that encode only task-relevant information in working memory. Extant literature supports a theoretical division of labor whereby lateral frontoparietal interactions underlie information maintenance and the striatum enacts the gate. Here, we reveal neocortical gating mechanisms in intracranial EEG patients by identifying rapid, within-trial changes in regional and inter-regional activities that predict subsequent behavioral outputs. Results first demonstrate information accumulation mechanisms that extend prior fMRI (i.e., regional high-frequency activity) and EEG evidence (inter-regional theta synchrony) of distributed neocortical networks in working memory. Second, results demonstrate that rapid changes in theta synchrony, reflected in changing patterns of default mode network connectivity, support filtering. Graph theoretical analyses further linked filtering in task-relevant information and filtering out irrelevant information to dorsal and ventral attention networks, respectively. Results establish a rapid neocortical theta network mechanism for flexible information encoding, a role previously attributed to the striatum.

Authors:

• Elizabeth L. Johnson

• Jack J. Lin

• David King-Stephens

• Peter B. Weber

• Kenneth D. Laxer

• Ignacio Saez

• Fady Girgis

• Mark D’Esposito

• Robert T. Knight

• David Badre

Date: 2023

DOI: https://doi.org/10.1038/s41467-023-38574-7

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Grasp-specific high-frequency broadband mirror neuron activity during reach-and-grasp movements in humans

Abstract:

Broadly congruent mirror neurons, responding to any grasp movement, and strictly congruent mirror neurons, responding only to specific grasp movements, have been reported in single-cell studies with primates. Delineating grasp properties in humans is essential to understand the human mirror neuron system with implications for behavior and social cognition. We analyzed electrocorticography data from a natural reach-and-grasp movement observation and delayed imitation task with 3 different natural grasp types of everyday objects. We focused on the classification of grasp types from high-frequency broadband mirror activation patterns found in classic mirror system areas, including sensorimotor, supplementary motor, inferior frontal, and parietal cortices. Classification of grasp types was successful during movement observation and execution intervals but not during movement retention. Our grasp type classification from combined and single mirror electrodes provides evidence for grasp-congruent activity in the human mirror neuron system potentially arising from strictly congruent mirror neurons.

Authros:

• Alexander M. Dreyer

• Leo Michalke

• Anat Perry

• Edward F. Chang

• Jack J. Lin

• Robert T. Knight

• Jochem W. Rieger

Date: 2022

DOI: https://doi.org/10.1093/cercor/bhac504

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Orbitofrontal cortex governs working memory for temporal order

abstract:

How do we think about time? Converging lesion and neuroimaging evidence indicates that orbitofrontal cortex (OFC) supports the encoding and retrieval of temporal context in long-term memory, which may contribute to confabulation in individuals with OFC damage. Here, we reveal that OFC damage diminishes working memory for temporal order, that is, the ability to disentangle the relative recency of events as they unfold. OFC lesions reduced working memory for temporal order but not spatial position, and individual deficits were commensurate with lesion size. Comparable effects were absent in patients with lesions restricted to lateral prefrontal cortex (PFC). Based on these findings, we propose that OFC supports understanding of the order of events. Well-documented behavioral changes in individuals with OFC damage may relate to impaired temporal-order understanding.

authors:

• Elizabeth L Johnson

• William K Chang

• Callum D Dewar

• Donna Sorensen

• Jack J Lin

• Anne-Kristin Solbakk

• Tor Endestad

• Pal G Larsson

• Jugoslav Ivanovic

• Torstein R Meling

• Donatella Scabini

• Robert T Knight

Date: 2022

DOI: https:// doi.org/10.1016/j.cub.2022.03.074.

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Left hemisphere dominance for bilateral kinematic encoding in the human brain

Abstract:

Neurophysiological studies in humans and nonhuman primates have revealed movement representations in both the contralateral and ipsilateral hemispheres. Inspired by clinical observations, we ask if this bilateral representation differs for the left and right hemispheres. Electrocorticography was recorded in human participants during an instructed-delay reaching task, with movements produced with either the contralateral or ipsilateral arm. Using a cross-validated kinematic encoding model, we found stronger bilateral encoding in the left hemisphere, an effect that was present during preparation and was amplified during execution. Consistent with this asymmetry, we also observed better across-arm generalization in the left hemisphere, indicating similar neural representations for right and left arm movements. Notably, these left hemisphere electrodes were centered over premotor and parietal regions. The more extensive bilateral encoding in the left hemisphere adds a new perspective to the pervasive neuropsychological finding that the left hemisphere plays a dominant role in praxis.

authors:

• Christina M Merrick

• Tanner C Dixon

• Assaf Breska

• Jack Lin

• Edward F Chang

• David King-Stephens

• Kenneth D Laxer

• Peter B Weber

• Jose Carmena

• Robert Thomas Knight

• Richard B Ivry

Date: 2022

DOI: : https://doi.org/10.7554/eLife.69977

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Orbitofrontal cortex governs working memory for temporal order

Abstract:

How do we think about time? Converging lesion and neuroimaging evidence indicates that orbitofrontal cortex (OFC) supports the encoding and retrieval of temporal context in long-term memory1, which may contribute to confabulation in individuals with OFC damage2. Here, we reveal that OFC damage diminishes working memory for temporal order, that is, the ability to disentangle the relative recency of events as they unfold. OFC lesions reduced working memory for temporal order but not spatial position, and individual deficits were commensurate with lesion size. Comparable effects were absent in patients with lesions restricted to lateral prefrontal cortex (PFC). Based on these findings, we propose that OFC supports understanding of the order of events. Well-documented behavioral changes in individuals with OFC damage2 may relate to impaired temporal-order understanding.

Authors:

• Elizabeth L. Johnson

• William K. Chang

• Callum D. Dewar

• Donna Sorensen

• Jack J. Lin

• Anne-Kristin Solbakk

• Tor Endestad

• Pal G. Larsson

• Jugoslav Ivanovic

• Torstein R. Meling

• Donatella Scabini

• Robert T. Knight

Date: 2022

DOI: https://doi.org/10.1016/j.cub.2022.03.074

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Intracranial recordings demonstrate medial temporal lobe engagement in visual search in humans

Abstract:

Visual search is a fundamental human behavior, which has been proposed to include two component processes: inefficient search (Search) and efficient search (Pop-out). According to extant research, these two processes map onto two separable neural systems located in the frontal and parietal association cortices. In the present study, we use intracranial recordings from 23 participants to delineate the neural correlates of Search and Pop-out with an unprecedented combination of spatiotemporal resolution and coverage across cortical and subcortical structures. First, we demonstrate a role for the medial temporal lobe in visual search, on par with engagement in frontal and parietal association cortex. Second, we show a gradient of increasing engagement over anatomical space from dorsal to ventral lateral frontal cortex. Third, we confirm previous work demonstrating nearly complete overlap in neural engagement across cortical regions in Search and Pop-out. We further demonstrate Pop-out selectivity manifesting as activity increase in Pop-out as compared to Search in a distributed set of sites including frontal cortex. This result is at odds with the view that Pop-out is implemented in low-level visual cortex or parietal cortex alone. Finally, we affirm a central role for the right lateral frontal cortex in Search.

Authors:

• S. J. Katarina Slama

• Richard Jimenez

• Sujayam Saha

• David King-Stephens

• Kenneth D Laxer

• Peter B Weber

• Tor Endestad

• Pål G Larsson

• Anne-Kristin Solbakk

• Jack J Lin

• Robert T Knight

Date: 2021

DOI: https://doi.org/10.1162/jocn_a_01739

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Medial orbitofrontal cortex, dorsolateral prefrontal cortex, and hippocampus differentially represent the event saliency

Abstract:

Two primary functions attributed to the hippocampus and prefrontal cortex (PFC) network are retaining the temporal and spatial associations of events and detecting deviant events. It is unclear, however, how these two functions converge into one mechanism. Here, we tested whether increased activity with perceiving salient events is a deviant detection signal or contains information about the event associations by reflecting the magnitude of deviance (i.e., event saliency). We also tested how the deviant detection signal is affected by the degree of anticipation. We studied regional neural activity when people watched a movie that had varying saliency of a novel or an anticipated flow of salient events. Using intracranial electroencephalography from 10 patients, we observed that high-frequency activity (50–150 Hz) in the hippocampus, dorsolateral PFC, and medial OFC tracked event saliency. We also observed that medial OFC activity was stronger when the salient events were anticipated than when they were novel. These results suggest that dorsolateral PFC and medial OFC, as well as the hippocampus, signify the saliency magnitude of events, reflecting the hierarchical structure of event associations.

Authors:

• Anna Jafarpour

• Sandon Griffin

• Jack J Lin

• Robert T Knight

Date: 2019

DOI: https://doi.org/10.1162/jocn_a_01392

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Temporal dynamics and response modulation across the human visual system in a spatial attention task: an ECoG study

Abstract:

The selection of behaviorally relevant information from cluttered visual scenes (often referred to as “attention”) is mediated by a cortical large-scale network consisting of areas in occipital, temporal, parietal, and frontal cortex that is organized into a functional hierarchy of feedforward and feedback pathways. In the human brain, little is known about the temporal dynamics of attentional processing from studies at the mesoscopic level of electrocorticography (ECoG), that combines millisecond temporal resolution with precise anatomical localization of recording sites. We analyzed high-frequency broadband responses (HFB) responses from 626 electrodes implanted in 8 epilepsy patients who performed a spatial attention task. Electrode locations were reconstructed using a probabilistic atlas of the human visual system. HFB responses showed high spatial selectivity and tuning, constituting ECoG response fields (RFs), within and outside the topographic visual system. In accordance with monkey physiology studies, both RF widths and onset latencies increased systematically across the visual processing hierarchy. We used the spatial specificity of HFB responses to quantitatively study spatial attention effects and their temporal dynamics to probe a hierarchical top-down model suggesting that feedback signals back propagate the visual processing hierarchy. Consistent with such a model, the strengths of attentional modulation were found to be greater and modulation latencies to be shorter in posterior parietal cortex, middle temporal cortex and ventral extrastriate cortex compared with early visual cortex. However, inconsistent with such a model, attention effects were weaker and more delayed in anterior parietal and frontal cortex.

Authors:

• Anne B. Martin

• Xiaofang Yang

• Yuri B. Saalmann

• Liang Wang

• Avgusta Shestyuk

• Jack J. Lin

• Josef Parvizi

• Robert T. Knight

• Sabine Kastner

Date: 2019

DOI: 10.1523/JNEUROSCI.1889-18.2018

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Spectral imprints of working memory for everyday associations in the frontoparietal network

ABSTRACT

How does the human brain rapidly process incoming information in working memory? In growing divergence from a single-region focus on the prefrontal cortex (PFC), recent work argues for emphasis on how distributed neural networks are rapidly coordinated in support of this central neurocognitive function. Previously, we showed that working memory for everyday “what,” “where,” and “when” associations depends on multiplexed oscillatory systems, in which signals of different frequencies simultaneously link the PFC to parieto-occipital and medial temporal regions, pointing to a complex web of sub-second, bidirectional interactions. Here, we used direct brain recordings to delineate the frontoparietal oscillatory correlates of working memory with high spatiotemporal precision. Seven intracranial patients with electrodes simultaneously localized to prefrontal and parietal cortices performed a visuospatial working memory task that operationalizes the types of identity and spatiotemporal information we encounter every day. First, task-induced oscillations in the same delta-theta (2–7 Hz) and alpha-beta (9–24 Hz) frequency ranges previously identified using scalp electroencephalography (EEG) carried information about the contents of working memory. Second, maintenance was linked to directional connectivity from the parietal cortex to the PFC. However, presentation of the test prompt to cue identity, spatial, or temporal information changed delta-theta coordination from a unidirectional, parietal-led system to a bidirectional, frontoparietal system. Third, the processing of spatiotemporal information was more bidirectional in the delta-theta range than was the processing of identity information, where alpha-beta connectivity did not exhibit sensitivity to the contents of working memory. These findings implicate a bidirectional delta-theta mechanism for frontoparietal control over the contents of working memory.

AUTHORS

• Elizabeth L. Johnson

• David King-Stephens

• Peter B. Weber

• Kenneth D. Laxer

• Jack J. Lin

• Robert T. Knight

Date: 2019

DOI: 10.3389/fnsys.2018.00065

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Hippocampal CA1 gamma power predicts the precision of spatial memory judgments

Abstract:

The hippocampus plays a critical role in spatial memory. However, the exact neural mechanisms underlying high-fidelity spatial memory representations are unknown. We report findings from presurgical epilepsy patients with bilateral hippocampal depth electrodes performing an object-location memory task that provided a broad range of spatial memory precision. During encoding, patients were shown a series of objects along the circumference of an invisible circle. At test, the same objects were shown at the top of the circle (0°), and patients used a dial to move the object to its location shown during encoding. Angular error between the correct location and the indicated location was recorded as a continuous measure of performance. By registering pre- and postimplantation MRI scans, we were able to localize the electrodes to specific hippocampal subfields. We found a correlation between increased gamma power, thought to reflect local excitatory activity, and the precision of spatial memory retrieval in hippocampal CA1 electrodes. Additionally, we found a similar relationship between gamma power and memory precision in the dorsolateral prefrontal cortex and a directional relationship between activity in this region and in the CA1, suggesting that the dorsolateral prefrontal cortex is involved in postretrieval processing. These results indicate that local processing in hippocampal CA1 and dorsolateral prefrontal cortex supports high-fidelity spatial memory representations.

Authors:

• Rebecca F. Stevenson

• Jie Zheng

• Lilit Mnatsakanyan

• Sumeet Vadera

• Robert T. Knight

• Jack J. Lin

• Michael A. Yassa

Date: 2018

DOI: 10.1073/pnas.1805724115

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Neural mechanisms of sustained attention are rhythmic

ABSTRACT

Classic models of attention suggest that sustained neural firing constitutes a neural correlate of sustained attention. However, recent evidence indicates that behavioral performance fluctuates over time, exhibiting temporal dynamics that closely resemble the spectral features of ongoing, oscillatory brain activity. Therefore, it has been proposed that periodic neuronal excitability fluctuations might shape attentional allocation and overt behavior. However, empirical evidence to support this notion is sparse. Here, we address this issue by examining data from large-scale subdural recordings, using two different attention tasks that track perceptual ability at high temporal resolution. Our results reveal that perceptual outcome varies as a function of the theta phase even in states of sustained spatial attention. These effects were robust at the single-subject level, suggesting that rhythmic perceptual sampling is an inherent property of the frontoparietal attention network. Collectively, these findings support the notion that the functional architecture of top-down attention is intrinsically rhythmic.

AUTHORS

• Randolph F. Helfrich

• Ian C. Fiebelkorn

• Sara M. Szczepanski

• Jack J. Lin

• Josef Parvizi

• Robert T. Knight

• Sabine Kastner

Date: 2018

DOI: 10.1016/j.neuron.2018.07.032

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Integrated analysis of anatomical and electrophysiological human intracranial data

ABSTRACT

Human intracranial electroencephalography (iEEG) recordings provide data with much greater spatiotemporal precision than is possible from data obtained using scalp EEG, magnetoencephalography (MEG), or functional MRI. Until recently, the fusion of anatomical data (MRI and computed tomography (CT) images) with electrophysiological data and their subsequent analysis have required the use of technologically and conceptually challenging combinations of software. Here, we describe a comprehensive protocol that enables complex raw human iEEG data to be converted into more readily comprehensible illustrative representations. The protocol uses an open-source toolbox for electrophysiological data analysis (FieldTrip). This allows iEEG researchers to build on a continuously growing body of scriptable and reproducible analysis methods that, over the past decade, have been developed and used by a large research community. In this protocol, we describe how to analyze complex iEEG datasets by providing an intuitive and rapid approach that can handle both neuroanatomical information and large electrophysiological datasets. We provide a worked example using an example dataset. We also explain how to automate the protocol and adjust the settings to enable analysis of iEEG datasets with other characteristics. The protocol can be implemented by a graduate student or postdoctoral fellow with minimal MATLAB experience and takes approximately an hour to execute, excluding the automated cortical surface extraction.

AUTHORS

• Arjen Stolk

• Sandon Griffin

• Roemer van der Meij

• Callum Dewar

• Ignacio Saez

• Jack J. Lin

• Giovanni Piantoni

• Jan-Mathijs Schoffelen

• Robert T. Knight 

• Robert Oostenveld 

Date: 2018

DOI: 10.1038/s41596-018-0009-6

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