In the auditory cortex (ACtx), intratelencephalic projection neurons are often found in layer (L) 5a, project locally to L2/3, and distally to ipsi-and contralateral cortex and striatum ( Games and Winer, 1988 Winer and Prieto, 2001 Yuan et al., 2011). Our findings underscore a duality among sub-cortical projection neurons, where L5 CF units are canonical broadcast neurons that integrate sensory inputs for transmission to distributed downstream targets, while L6 CT neurons are positioned to regulate thalamocortical response gain and selectivity.Ĭorticofugal (CF) neurons broadly fall into two classes: intratelencephalic and sub-cortical ( Harris and Mrsic-Flogel, 2013 Harris and Shepherd, 2015).

By contrast, L6 CT spikes drove robust and sustained activity, particularly in local fast-spiking interneurons. L5 CF spikes lagged behind neighboring units and imposed weak feedforward excitation within the local column. Whereas L5 CF neurons showed broad stimulus selectivity with sluggish response latencies and extended temporal non-linearities, L6 CTs exhibited sparse selectivity and rapid temporal processing.

Here, we made optogenetically guided recordings from L5 corticofugal (CF) and L6 corticothalamic (CT) neurons in the auditory cortex of awake mice to discern differences in sensory processing and underlying patterns of functional connectivity. Cortical layers (L) 5 and 6 are populated by intermingled cell-types with distinct inputs and downstream targets.

Between the lines kd williamson