title: Transient suppression of broadband gamma power in the default-mode network is correlated with task complexity and subject performance.
abstract: 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.
authors: Lyon Neuroscience Research Center, INSERM U1028, CNRS UMR5292, Brain Dynamics and Cognition Team, F-69500 Lyon-Bron, France.
authors: Tomas
authors: T
authors: Ossandón
authors: Karim
authors: K
authors: Jerbi
authors: Juan R
authors: JR
authors: Vidal
authors: Dimitri J
authors: DJ
authors: Bayle
authors: Marie-Anne
authors: MA
authors: Henaff
authors: Julien
authors: J
authors: Jung
authors: Lorella
authors: L
authors: Minotti
authors: Olivier
authors: O
authors: Bertrand
authors: Philippe
authors: P
authors: Kahane
authors: Jean-Philippe
authors: JP
authors: Lachaux
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D003198:Computer Simulation; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D017711:Nonlinear Dynamics; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D013223:Statistics as Topic; D013997:Time Factors; D055815:Young Adult