Differential electrophysiological response during rest, self-referential, and non-self-referential tasks in human posteromedial cortex.
Mohammad Dastjerdi, Brett L Foster, Sharmin Nasrullah, Andreas M Rauschecker, Robert F. Dougherty, Jennifer D Townsend, Catie Chang, Michael D. Greicius, Vinod Menon, Daniel P Kennedy, Josef Parvizi
Proceedings of the National Academy of Sciences of the United States of America February 15, 2011 DOI: 10.1073/pnas.1017098108 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Population | Human patients with intracranial electrodes in the posteromedial cortex |
| Key findings | The majority of PMC sites showed increased broad gamma band activity during rest, while some sites proximal to the retrosplenial cortex responded selectively to autobiographical stimuli. No site responded to both rest and autobiographical conditions, indicating functional heterogeneity within the DMN core. |
Abstract
The electrophysiological basis for higher brain activity during rest and internally directed cognition within the human default mode network (DMN) remains largely unknown. Here we use intracranial recordings in the human posteromedial cortex (PMC), a core node within the DMN, during conditions of cued rest, autobiographical judgments, and arithmetic processing. We found a heterogeneous profile of PMC responses in functional, spatial, and temporal domains. Although the majority of PMC sites showed increased broad gamma band activity (30-180 Hz) during rest, some PMC sites, proximal to the retrosplenial cortex, responded selectively to autobiographical stimuli. However, no site responded to both conditions, even though they were located within the boundaries of the DMN identified with resting-state functional imaging and similarly deactivated during arithmetic processing. These findings, which provide electrophysiological evidence for heterogeneity within the core of the DMN, will have important implications for neuroimaging studies of the DMN.