Cell Class-Dependent Intracortical Connectivity and Output Dynamics of Layer 6 Projection Neurons of the Rat Primary Visual Cortex

Florence Cotel, Lee N Fletcher, Simon Kalita-de Croft, John Apergis-Schoute, Stephen R Williams
2017 Cerebral Cortex  
Neocortical information processing is powerfully influenced by the activity of layer 6 projection neurons through control of local intracortical and subcortical circuitry. Morphologically distinct classes of layer 6 projection neuron have been identified in the mammalian visual cortex, which exhibit contrasting receptive field properties, but little information is available on their functional specificity. To address this we combined anatomical tracing techniques with high-resolution patchclamp
more » ... recording to identify morphological and functional distinct classes of layer 6 projection neurons in the rat primary visual cortex, which innervated separable subcortical territories. Multisite whole-cell recordings in brain slices revealed that cortico-claustral and cortico-thalamic layer 6 projection neurons were sparsely and reciprocally synaptically inter-connected, but exhibited cellclass, but not target-cell-dependent rules of use-dependent depression and facilitation of unitary excitatory synaptic output. These functionally distinct neuronal classes were differentially innervated by columnar excitatory circuitry, with cortico-claustral, but not cortico-thalamic, neurons powerfully driven by layer 4 pyramidal neurons, and long range pathways conveyed in neocortical layer 1. Our results therefore reveal projection target-specific, functionally distinct, streams of layer 6 output in the rodent neocortex. Cotel, F. et al. 2
doi:10.1093/cercor/bhx134 pmid:28591797 fatcat:wr4rtq5tbfdadk5g6ifylpvnki