Low-frequency direct cortical stimulation of left superior frontal gyrus enhances working memory performance

Sankaraleengam Alagapan; Caroline Lustenberger; Eldad Hadar; Hae Won Shin; Flavio Frӧhlich

doi:10.1016/j.neuroimage.2018.09.064

Low-frequency direct cortical stimulation of left superior frontal gyrus enhances working memory performance

Neuroimage. 2019 Jan 1:184:697-706. doi: 10.1016/j.neuroimage.2018.09.064. Epub 2018 Sep 27.

Authors

Sankaraleengam Alagapan¹, Caroline Lustenberger², Eldad Hadar³, Hae Won Shin⁴, Flavio Frӧhlich⁵

Affiliations

¹ Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Carolina Center for Neurostimulation, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
² Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
³ Department of Neurosurgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
⁴ Department of Neurosurgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
⁵ Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Carolina Center for Neurostimulation, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. Electronic address: flavio_frohlich@med.unc.edu.

Abstract

The neural substrates of working memory are spread across prefrontal, parietal and cingulate cortices and are thought to be coordinated through low frequency cortical oscillations in the theta (3-8 Hz) and alpha (8-12 Hz) frequency bands. While the functional role of many subregions have been elucidated using neuroimaging studies, the role of superior frontal gyrus (SFG) is not yet clear. Here, we combined electrocorticography and direct cortical stimulation in three patients implanted with subdural electrodes to assess if superior frontal gyrus is indeed involved in working memory. We found left SFG exhibited task-related modulation of oscillations in the theta and alpha frequency bands specifically during the encoding epoch. Stimulation at the frequency matched to the endogenous oscillations resulted in reduced reaction times in all three participants. Our results provide evidence for SFG playing a functional role in working memory and suggest that SFG may coordinate working memory through low-frequency oscillations thus bolstering the feasibility of using intracranial electric stimulation for restoring cognitive function.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Brain Mapping / methods
Electric Stimulation
Electrocorticography
Electrodes, Implanted
Epilepsy / therapy
Female
Humans
Male
Memory, Short-Term / physiology*
Middle Aged
Prefrontal Cortex / physiology*
Young Adult

Abstract

Publication types

MeSH terms

Grants and funding