Abstract:
Broadband high-frequency activity (BHA; 70 to 150 Hz), also known as “high gamma,” a key analytic signal in human intracranial (electrocorticographic) recordings, is often assumed to reflect local neural firing [multiunit activity (MUA)]. As the precise physiological substrates of BHA are unknown, this assumption remains controversial. Our analysis of laminar multielectrode data from V1 and A1 in monkeys outlines two components of stimulus-evoked BHA distributed across the cortical layers: an “early-deep” and “late-superficial” response. Early-deep BHA has a clear spatial and temporal overlap with MUA. Late-superficial BHA was more prominent and accounted for more of the BHA signal measured near the cortical pial surface. However, its association with local MUA is weak and often undetectable, consistent with the view that it reflects dendritic processes separable from local neuronal firing.
Authors:
Marcin Leszczyński
Annamaria Barczak
Yoshinao Kajikawa
Istvan Ulbert
Arnaud Y Falchier
Idan Tal
Saskia Haegens
Lucia Melloni
Robert T Knight
Charles E Schroeder
Date: 2020
DOI: 10.1126/sciadv.abb0977