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Comparison of tuning properties of gamma and high-gamma power in local field potential (LFP) versus electrocorticogram (ECoG) in visual cortex

Dubey, A and Ray, S (2020) Comparison of tuning properties of gamma and high-gamma power in local field potential (LFP) versus electrocorticogram (ECoG) in visual cortex. In: Scientific Reports, 10 (1).

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Official URL: https://doi.org/10.1038/s41598-020-61961-9


Electrocorticogram (ECoG), obtained from macroelectrodes placed on the cortex, is typically used in drug-resistant epilepsy patients, and is increasingly being used to study cognition in humans. These studies often use power in gamma (30–70 Hz) or high-gamma (>80 Hz) ranges to make inferences about neural processing. However, while the stimulus tuning properties of gamma/high-gamma power have been well characterized in local field potential (LFP; obtained from microelectrodes), analogous characterization has not been done for ECoG. Using a hybrid array containing both micro and ECoG electrodes implanted in the primary visual cortex of two female macaques (for some stimulus conditions, separate ECoG and microelectrode arrays in two additional male macaques were also used), we compared the stimulus tuning preferences of gamma/high-gamma power in LFP versus ECoG in up to four monkeys, and found them to be surprisingly similar. High-gamma power, thought to index the average firing rate around the electrode, was highest for the smallest stimulus (0.3° radius), and decreased with increasing size in both LFP and ECoG, suggesting local origins of both signals. Further, gamma oscillations were similarly tuned in LFP and ECoG to stimulus orientation, contrast and spatial frequency. This tuning was significantly weaker in electroencephalogram (EEG), suggesting that ECoG is more like LFP than EEG. Overall, our results validate the use of ECoG in clinical and basic cognitive research. © 2020, The Author(s).

Item Type: Journal Article
Publication: Scientific Reports
Publisher: Nature Research
Additional Information: The copyright for this article belongs to The Author(s).
Keywords: action potential; animal; brain mapping; electrocorticography; female; Haplorhini; Macaca; male; microelectrode; nerve cell; orientation; photostimulation; physiology; procedures; visual cortex, Action Potentials; Animals; Brain Mapping; Electrocorticography; Female; Haplorhini; Macaca; Male; Microelectrodes; Neurons; Orientation; Photic Stimulation; Visual Cortex
Department/Centre: Division of Biological Sciences > Centre for Neuroscience
Date Deposited: 10 Jan 2023 06:00
Last Modified: 10 Jan 2023 06:00
URI: https://eprints.iisc.ac.in/id/eprint/78988

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