A widely distributed spectral signature of task-negative electrocorticography responses revealed during a visuomotor task in the human cortex

Michal Ramot, Lior Fisch, Michal Harel, Svetlana Kipervasser, Fani Andelman, Miri Y. Neufeld, Uri Kramer, Itzhak Fried, Rafael Malach*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

While research of human cortical function has typically focused on task-related increases in neuronal activity, there is a growing interest in the complementary phenomenon-namely, task-induced reductions. Recent human BOLD fMRI studies have associated such reductions with a specific network termed the default mode network (DMN). However, detailed understanding of the spatiotemporal patterns of task-negative responses and particularly how they compare across different cortical networks is lacking. Here we examined this issue in a large-scale electrocorticography study in patients performing a demanding backward masking task. Our results uncovered rapid (>1 s) task-induced reductions in gamma power, often concomitant with power increase in alpha/beta bands. Importantly, these responses were found both in the DMN and sensory-motor networks. Comparing the task-negative responses across these different networks revealed similar spectral signatures and dynamics. We hypothesize that the task-negative responses may reflect a cortical switching mechanism whose role is to steer activity away from cortical networks, which are inappropriate for the task at hand.

Original languageEnglish
Pages (from-to)10458-10469
Number of pages12
JournalJournal of Neuroscience
Volume32
Issue number31
DOIs
StatePublished - 1 Aug 2012

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