Exploring the electrophysiological correlates of the default-mode network with intracerebral EEG

Jerbi, Karim; Vidal, Juan R.; Ossandón, Tomás; Dalal, Sarang S.; Jung, Julien; Hoffmann, D.; Minotti, Lorella; Bertrand, Olivier; Kahane, Philippe; Lachaux, Jean-Philippe

doi:10.3389/fnsys.2010.00027

Cited by 100 publications

(106 citation statements)

References 76 publications

(130 reference statements)

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“…Negative responses (e.g., energy decreases relative to baseline) were also found in the temporo-parietal junction (TPJ) and the ventral-lateral prefrontal cortex (VLPFC) (data not shown). As previously shown by our group, they coincide with task-unspecific deactivations of the default-mode network Mainy et al, 2008;Jerbi et al, 2010).…”

Section: High-frequency Energy Modulations During Readingsupporting

confidence: 50%

Long-Distance Amplitude Correlations in the High Gamma Band Reveal Segregation and Integration within the Reading Network

Vidal¹,

Freyermuth²,

Jerbi³

et al. 2012

J. Neurosci.

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Reading sentences involves a distributed network of brain regions acting in concert surrounding the left sylvian fissure. The mechanisms of neural communication underlying the extraction and integration of verbal information across subcomponents of this reading network are still largely unknown. We recorded intracranial EEG activity in 12 epileptic human patients performing natural sentence reading and analyzed long-range corticocortical interactions between local neural activations. During a simple task contrasting semantic, phonological, and purely visual processes, we found process-specific neural activity elicited at the single-trial level, characterized by energy increases in a broad gamma band (40 -150 Hz). Correlation analysis between task-induced gamma-band activations revealed a selective fragmentation of the network into specialized subnetworks supporting sentence-level semantic analysis and phonological processing. We extend the implications of our results beyond reading, to propose that gamma-band amplitude correlations might constitute a fundamental mechanism for large-scale neural integration during high-level cognition.

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Section: High-frequency Energy Modulations During Readingsupporting

confidence: 50%

Long-Distance Amplitude Correlations in the High Gamma Band Reveal Segregation and Integration within the Reading Network

Vidal¹,

Freyermuth²,

Jerbi³

et al. 2012

J. Neurosci.

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“…Conversely, here we demonstrate, using direct electrophysiological recordings in the human brain, that all DMN areas, which are known to exhibit negative BOLD responses, display suppressions of gammaband power during task engagement. Critically, our results significantly extend previous invasive studies of task-related gamma power suppressions in humans (Lachaux et al, 2008;Miller et al, 2009;Jerbi et al, 2010;Dastjerdi et al, 2011) and monkeys (Shmuel et al, 2006;Hayden et al, 2009). In addition to probing DMN electrophysiology via an unprecedented large-scale sampling of the human brain (14 subjects, 1730 recording sites), the present study is above all the first to reveal the millisecond temporal features (onset and duration) of cortical gamma power decreases across the entire default-mode network, and it is also the first to report significant correlations between the transient power suppressions and behavior (duration of task engagement and performance).…”

Section: Discussionsupporting

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Transient Suppression of Broadband Gamma Power in the Default-Mode Network Is Correlated with Task Complexity and Subject Performance

Ossandón¹,

Jerbi²,

Vidal³

et al. 2011

J. Neurosci.

200

172

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Task performance is associated with increased brain metabolism but also with prominent deactivation in specific brain structures known as the default-mode network (DMN). The role of DMN deactivation remains enigmatic in part because its electrophysiological correlates, temporal dynamics, and link to behavior are poorly understood. Using extensive depth electrode recordings in humans, we provide first electrophysiological evidence for a direct correlation between the dynamics of power decreases in the DMN and individual subject behavior. We found that all DMN areas displayed transient suppressions of broadband gamma (60 -140 Hz) power during performance of a visual search task and, critically, we show for the first time that the millisecond range duration and extent of the transient gamma suppressions are correlated with task complexity and subject performance. In addition, trial-by-trial correlations revealed that spatially distributed gamma power increases and decreases formed distinct anticorrelated large-scale networks. Beyond unraveling the electrophysiological basis of DMN dynamics, our results suggest that, rather than indicating a mere switch to a global exteroceptive mode, DMN deactivation encodes the extent and efficiency of our engagement with the external world. Furthermore, our findings reveal a pivotal role for broadband gamma modulations in the interplay between task-positive and task-negative networks mediating efficient goal-directed behavior and facilitate our understanding of the relationship between electrophysiology and neuroimaging studies of intrinsic brain networks.

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“…Furthermore, this suppression in firing rate is correlated with behavioral performance, where lower levels of PCC firing suppression are associated with longer reaction times (RTs) and higher error rate, a correlation also previously reported with fMRI in humans (11,12). Similarly, direct cortical recordings using electrocorticography (ECoG) from human DMN (13)(14)(15)(16) have shown suppression of broadband γ-power [a correlate of population firing rate (17,18)] during attentional effort. More recently, this broadband suppression across human DMN regions has also been shown to correlate with behavioral performance (16).…”

mentioning

confidence: 87%

Neural populations in human posteromedial cortex display opposing responses during memory and numerical processing

Foster

Dastjerdi

Parvizi

2012

Proc. Natl. Acad. Sci. U.S.A.

102

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Our understanding of the human default mode network derives primarily from neuroimaging data but its electrophysiological correlates remain largely unexplored. To address this limitation, we recorded intracranially from the human posteromedial cortex (PMC), a core structure of the default mode network, during various conditions of internally directed (e.g., autobiographical memory) as opposed to externally directed focus (e.g., arithmetic calculation). We observed late-onset (>400 ms) increases in broad high γ-power (70-180 Hz) within PMC subregions during memory retrieval. High γ-power was significantly reduced or absent when subjects retrieved self-referential semantic memories or responded to selfjudgment statements, respectively. Conversely, a significant deactivation of high γ-power was observed during arithmetic calculation, the duration of which correlated with reaction time at the signaltrial level. Strikingly, at each recording site, the magnitude of activation during episodic autobiographical memory retrieval predicted the degree of suppression during arithmetic calculation. These findings provide important anatomical and temporal details-at the neural population level-of PMC engagement during autobiographical memory retrieval and address how the same populations are actively suppressed during tasks, such as numerical processing, which require externally directed attention.electrocorticography | episodic memory | numerical cognition O ur ability to successfully direct and maintain attention to the external world relies on the coordinated activation of several putative attentional brain networks. Over the past decade brain imaging techniques, such as functional MRI (fMRI), have also revealed a select group of brain regions, now well-known as the default mode network (DMN), which deactivate during tasks of externally directed attention (1, 2). Conversely, the DMN shows higher activity during tasks requiring internally focused "self-referential" processing (3-5). Despite the many advances made by neuroimaging studies of DMN function, similar progress in the electrophysiological domain has remained relatively limited. This scarcity of investigation is mostly because the core structures of the DMN are anatomically hidden on the medial surface of the brain, and thus their location and orientation is suboptimal for detection with scalp electroencephalography (EEG). One region of particular interest is the posteromedial cortex (PMC), which is the main hub of the DMN in the human (2, 6) and nonhuman primate (7, 8) brains (Fig. 1), and encompasses the posterior cingulate cortex (PCC), retrosplenial cortex (RSC), precuneus, and Brodmann area 31 (9). Ultimately, more invasive techniques using intracranial electrophysiological recordings from the human brain are methodologically preferable for studying these regions, but obtaining such data has been rare and logistically challenging.Recent invasive electrophysiological studies of the DMN have highlighted its well-known deactivation during conditions of externally d...

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Exploring the electrophysiological correlates of the default-mode network with intracerebral EEG

Cited by 100 publications

References 76 publications

Long-Distance Amplitude Correlations in the High Gamma Band Reveal Segregation and Integration within the Reading Network

Long-Distance Amplitude Correlations in the High Gamma Band Reveal Segregation and Integration within the Reading Network

Transient Suppression of Broadband Gamma Power in the Default-Mode Network Is Correlated with Task Complexity and Subject Performance

Neural populations in human posteromedial cortex display opposing responses during memory and numerical processing

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