Abstract

Although the mammalian neocortex has a clear laminar organization, layer-specific neuronal computations remain to be uncovered. Several studies suggest that gamma band activity in primary visual cortex (V1) is produced in granular and superficial layers and is associated with the processing of visual input [1Maier A. Adams G.K. Aura C. Leopold D.A. Distinct superficial and deep laminar domains of activity in the visual cortex during rest and stimulation.Front. Syst. Neurosci. 2010; 4: 31PubMed Google Scholar, 2Jensen O. Kaiser J. Lachaux J.P. Human gamma-frequency oscillations associated with attention and memory.Trends Neurosci. 2007; 30: 317-324Abstract Full Text Full Text PDF PubMed Scopus (857) Google Scholar, 3Fries P. Nikolić D. Singer W. The gamma cycle.Trends Neurosci. 2007; 30: 309-316Abstract Full Text Full Text PDF PubMed Scopus (817) Google Scholar]. Oscillatory alpha band activity in deeper layers has been proposed to modulate neuronal excitability associated with changes in arousal and cognitive factors [4Thut G. Miniussi C. New insights into rhythmic brain activity from TMS-EEG studies.Trends Cogn. Sci. 2009; 13: 182-189Abstract Full Text Full Text PDF PubMed Scopus (312) Google Scholar, 5Sauseng P. Klimesch W. Heise K.F. Gruber W.R. Holz E. Karim A.A. Glennon M. Gerloff C. Birbaumer N. Hummel F.C. Brain oscillatory substrates of visual short-term memory capacity.Curr. Biol. 2009; 19: 1846-1852Abstract Full Text Full Text PDF PubMed Scopus (475) Google Scholar, 6Klimesch W. Sauseng P. Hanslmayr S. EEG alpha oscillations: the inhibition-timing hypothesis.Brain Res. Brain Res. Rev. 2007; 53: 63-88Crossref PubMed Scopus (2418) Google Scholar, 7Jensen O. Bonnefond M. VanRullen R. An oscillatory mechanism for prioritizing salient unattended stimuli.Trends Cogn. Sci. 2012; 16: 200-206Abstract Full Text Full Text PDF PubMed Scopus (295) Google Scholar]. To investigate the layer-specific interplay between these two phenomena, we characterized the coupling between alpha and gamma band activity of the local field potential in V1 of the awake macaque. Using multicontact laminar electrodes to measure spontaneous signals simultaneously from all layers of V1, we found a robust coupling between alpha phase in the deeper layers and gamma amplitude in granular and superficial layers. Moreover, the power in the two frequency bands was anticorrelated. Taken together, these findings demonstrate robust interlaminar cross-frequency coupling in the visual cortex, supporting the view that neuronal activity in the alpha frequency range phasically modulates processing in the cortical microcircuit in a top-down manner [7Jensen O. Bonnefond M. VanRullen R. An oscillatory mechanism for prioritizing salient unattended stimuli.Trends Cogn. Sci. 2012; 16: 200-206Abstract Full Text Full Text PDF PubMed Scopus (295) Google Scholar].