Format

Send to

Choose Destination
Neuroscience. 2020 Jan 15;425:194-216. doi: 10.1016/j.neuroscience.2019.11.001. Epub 2019 Nov 28.

Tonic Resting State Hubness Supports High Gamma Activity Defined Verbal Memory Encoding Network in Epilepsy.

Author information

1
Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States.
2
School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
3
Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, United States.
4
Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA 19107, United States.
5
Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States. Electronic address: Joseph.Tracy@Jefferson.edu.

Abstract

High gamma activity (HGA) of verbal-memory encoding using invasive-electroencephalogram has laid the foundation for numerous studies testing the integrity of memory in diseased populations. Yet, the functional connectivity characteristics of networks subserving these memory linkages remains uncertain. By integrating this electrophysiological biomarker of memory encoding from IEEG with resting-state BOLD fluctuations, we estimated the segregation and hubness of HGA-memory regions in drug-resistant epilepsy patients and matched healthy controls. HGA-memory regions express distinctly different hubness compared to neighboring regions in health and in epilepsy, and this hubness was more relevant than segregation in predicting verbal memory encoding. The HGA-memory network comprised regions from both the cognitive control and primary processing networks, validating that effective verbal-memory encoding requires integrating brain functions, and is not dominated by a central cognitive core. Our results demonstrate a tonic intrinsic set of functional connectivity, which provides the necessary conditions for effective, phasic, task-dependent memory encoding.

KEYWORDS:

betweenness centrality; high-gamma activity; hubness; intrinsic networks; participation coefficient; verbal memory

PMID:
31786346
PMCID:
PMC6945984
[Available on 2021-01-15]
DOI:
10.1016/j.neuroscience.2019.11.001

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center