Publication DetailsJ Neurophysiology Acute Mouse Cortex Visual Penetrating Electrode A1x16-3mm-50-177
GammaÂ oscillationsÂ are a robust component of sensory responses but are also part of the backgroundÂ spontaneousÂ activity of the brain. To determine whether the properties ofÂ gammaÂ oscillationsÂ in cortex are specific to their mechanism of generation, we compared in mouse visual cortex in vivo the laminar geometry and single-neuron rhythmicity ofÂ oscillationsÂ produced during sensory representation with those occurring spontaneously in the absence of stimulation. In mouse visual cortex under anesthesia (isoflurane and xylazine), visual stimulation triggeredoscillationsÂ mainly between 20 and 50 Hz, which, because of their similar functional significance toÂ gammaÂ oscillationsÂ in higher mammals, we define here asÂ gammaÂ range. Sensory representation in visual cortex specifically increasedÂ gammaÂ oscillation amplitude in the supragranular (L2/3) and granular (L4) layers and strongly entrained putative excitatory and inhibitory neurons in infragranular layers, whileÂ spontaneousÂ gammaoscillationsÂ were distributed evenly through theÂ corticalÂ depth and primarily entrained putative inhibitory neurons in the infragranular (L5/6)Â corticallayers. The difference in laminar distribution ofÂ gammaÂ oscillationsÂ during the two different conditions may result from differences in the source of excitatory input to the cortex. In addition, modulation of superficialÂ gammaÂ oscillation amplitude did not result in a corresponding change in deep-layerÂ oscillations, suggesting that superficial and deep layers of cortex may utilize independent but related networks forÂ gammaÂ generation. These results demonstrate that stimulus-drivenÂ gammaÂ oscillationsÂ engageÂ corticalÂ circuitryÂ in a manner distinct from spontaneous oscillations and suggest multiple networks for the generation ofÂ gammaÂ oscillationsÂ in cortex.
J Neurophysiol.Â 2016 Apr;115(4):1821-35. doi: 10.1152/jn.00137.2015. Epub 2015 Dec 30.http://jn.physiology.org/content/115/4/1821.full.pdf+html April 1, 2016 US Food and Drug Administration