Network-Targeted, Multi-site Direct Cortical Stimulation Enhances Working Memory by Modulating Phase Lag of Low-Frequency Oscillations

Sankaraleengam Alagapan; Justin Riddle; Wei Angel Huang; Eldad Hadar; Hae Won Shin; Flavio Fröhlich

doi:10.1016/j.celrep.2019.10.072

Network-Targeted, Multi-site Direct Cortical Stimulation Enhances Working Memory by Modulating Phase Lag of Low-Frequency Oscillations

Cell Rep. 2019 Nov 26;29(9):2590-2598.e4. doi: 10.1016/j.celrep.2019.10.072.

Authors

Sankaraleengam Alagapan¹, Justin Riddle¹, Wei Angel Huang², Eldad Hadar³, Hae Won Shin⁴, Flavio Fröhlich⁵

Affiliations

¹ Carolina Center for Neurostimulation, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Psychiatry, 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 Carolina Center for Neurostimulation, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; 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 Cell Biology and Physiology, 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; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. Electronic address: [email protected].

Abstract

Working memory is mediated by the coordinated activation of frontal and parietal cortices occurring in the theta and alpha frequency ranges. Here, we test whether electrically stimulating frontal and parietal regions at the frequency of interaction is effective in modulating working memory. We identify working memory nodes that are functionally connected in theta and alpha frequency bands and intracranially stimulate both nodes simultaneously in participants performing working memory tasks. We find that in-phase stimulation results in improvements in performance compared to sham stimulation. In addition, in-phase stimulation results in decreased phase lag between regions within working memory network, while anti-phase stimulation results in increased phase lag, suggesting that shorter phase lag in oscillatory connectivity may lead to better performance. The results support the idea that phase lag may play a key role in information transmission across brain regions. Thus, brain stimulation strategies to improve cognition may require targeting multiple nodes of brain networks.

Keywords: brain stimulation; cortical oscillations; direct cortical stimulation; human neuroscience; intracranial eeg; phase lag; working memory.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Brain Mapping
Electroencephalography / methods*
Female
Humans
Male
Memory, Short-Term / physiology*

Abstract

Publication types

MeSH terms

Grants and funding