TY - JOUR
T1 - Laminar profile and physiology of the α rhythm in primary visual, auditory, and somatosensory regions of neocortex
AU - Haegens, Saskia
AU - Barczak, Annamaria
AU - Musacchia, Gabriella
AU - Lipton, Michael L.
AU - Mehta, Ashesh D.
AU - Lakatos, Peter
AU - Schroeder, Charles E.
N1 - Publisher Copyright:
©2015 the authors.
PY - 2015/10/21
Y1 - 2015/10/21
N2 - The functional significance of the α rhythm is widely debated. It has been proposed that α reflects sensory inhibition and/or a temporal sampling or “parsing” mechanism. There is also continuing disagreement over the more fundamental questions of which cortical layers generate α rhythms and whether the generation of α is equivalent across sensory systems. To address these latter questions, we analyzed laminar profiles of local field potentials (LFPs) and concomitant multiunit activity (MUA) from macaque V1, S1, and A1 during both spontaneous activity and sensory stimulation. Current source density (CSD) analysis of laminar LFP profiles revealed α current generators in the supragranular, granular, and infragranular layers.MUAphase-locked to local current source/sink configurations confirmed that α rhythms index local neuronal excitability fluctuations. CSD-defined α generators were strongest in the supragranular layers, whereas LFP α power was greatest in the infragranular layers, consistent with some of the previous reports. The discrepancy between LFP and CSD findings appears to be attributable to contamination of the infragranular LFP signal by activity that is volume-conducted from the stronger supragranular α generators. The presence of α generators across cortical depth in V1, S1, and A1 suggests the involvement of α in feedforward as well as feedback processes and is consistent with the view that α rhythms, perhaps in addition to a role in sensory inhibition, may parse sensory input streams in a way that facilitates communication across cortical areas.
AB - The functional significance of the α rhythm is widely debated. It has been proposed that α reflects sensory inhibition and/or a temporal sampling or “parsing” mechanism. There is also continuing disagreement over the more fundamental questions of which cortical layers generate α rhythms and whether the generation of α is equivalent across sensory systems. To address these latter questions, we analyzed laminar profiles of local field potentials (LFPs) and concomitant multiunit activity (MUA) from macaque V1, S1, and A1 during both spontaneous activity and sensory stimulation. Current source density (CSD) analysis of laminar LFP profiles revealed α current generators in the supragranular, granular, and infragranular layers.MUAphase-locked to local current source/sink configurations confirmed that α rhythms index local neuronal excitability fluctuations. CSD-defined α generators were strongest in the supragranular layers, whereas LFP α power was greatest in the infragranular layers, consistent with some of the previous reports. The discrepancy between LFP and CSD findings appears to be attributable to contamination of the infragranular LFP signal by activity that is volume-conducted from the stronger supragranular α generators. The presence of α generators across cortical depth in V1, S1, and A1 suggests the involvement of α in feedforward as well as feedback processes and is consistent with the view that α rhythms, perhaps in addition to a role in sensory inhibition, may parse sensory input streams in a way that facilitates communication across cortical areas.
KW - Auditory
KW - Laminar
KW - Somatosensory
KW - Visual
KW - α rhythm
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U2 - 10.1523/JNEUROSCI.0600-15.2015
DO - 10.1523/JNEUROSCI.0600-15.2015
M3 - Article
C2 - 26490871
AN - SCOPUS:84944909842
SN - 0270-6474
VL - 35
SP - 14341
EP - 14352
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 42
ER -