Within-subject reaction time variability: Role of cortical networks and underlying neurophysiological mechanisms.

TitleWithin-subject reaction time variability: Role of cortical networks and underlying neurophysiological mechanisms.
Publication TypeJournal Article
Year of Publication2021
AuthorsParaskevopoulou, SE, Coon, WG, Brunner, P, Miller, KJ, Schalk, G
Date Published08/2021
KeywordsAdult, Algorithms, Alpha Rhythm, Cerebral Cortex, Connectome, Electrocorticography, Female, Gamma Rhythm, Humans, Male, Middle Aged, Nerve Net, Psychomotor Performance, Reaction Time, Young Adult

Variations in reaction time are a ubiquitous characteristic of human behavior. Extensively documented, they have been successfully modeled using parameters of the subject or the task, but the neural basis of behavioral reaction time that varies within the same subject and the same task has been minimally studied. In this paper, we investigate behavioral reaction time variance using 28 datasets of direct cortical recordings in humans who engaged in four different types of simple sensory-motor reaction time tasks. Using a previously described technique that can identify the onset of population-level cortical activity and a novel functional connectivity algorithm described herein, we show that the cumulative latency difference of population-level neural activity across the task-related cortical network can explain up to 41% of the trial-by-trial variance in reaction time. Furthermore, we show that reaction time variance may primarily be due to the latencies in specific brain regions and demonstrate that behavioral latency variance is accumulated across the whole task-related cortical network. Our results suggest that population-level neural activity monotonically increases prior to movement execution, and that trial-by-trial changes in that increase are, in part, accounted for by inhibitory activity indexed by low-frequency oscillations. This pre-movement neural activity explains 19% of the measured variance in neural latencies in our data. Thus, our study provides a mechanistic explanation for a sizable fraction of behavioral reaction time when the subject's task is the same from trial to trial.

Alternate JournalNeuroimage
PubMed ID33957232
PubMed Central IDPMC8882389
Grant ListKL2 TR002379 / TR / NCATS NIH HHS / United States
U24 NS109103 / NS / NINDS NIH HHS / United States
U01 NS108916 / NS / NINDS NIH HHS / United States
R01 EB026439 / EB / NIBIB NIH HHS / United States
P50 MH109429 / MH / NIMH NIH HHS / United States
P41 EB018783 / EB / NIBIB NIH HHS / United States

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