Cell Class-Dependent Intracortical Connectivity and Output Dynamics of Layer 6 Projection Neurons of the Rat Primary Visual Cortex
journal contributionposted on 2019-04-04, 11:37 authored by F Cotel, LN Fletcher, S Kalita-de Croft, J Apergis-Schoute, SR Williams
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 patch-clamp 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 corticoclaustral and corticothalamic layer 6 projection neurons exhibited similar somatically recorded electrophysiological properties. These classes of layer 6 projection neurons were sparsely and reciprocally synaptically interconnected, but could be differentiated by cell-class, but not target-cell-dependent rules of use-dependent depression and facilitation of unitary excitatory synaptic output. Corticoclaustral and corticothalamic layer 6 projection neurons were differentially innervated by columnar excitatory circuitry, with corticoclaustral, but not corticothalamic, 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.
Australian Research Council (FT100100502 and DP130101630), and the National Health and Medical Research Council (APP1004575) to S.R.W., and Fellowships from the National Science Foundation (0804305) and Royal Society to J.A.-S., the Hand Heart Pocket Fund to S.R.W., and an Australian Postgraduate Award to L.N.F. Neurolucida at the Queensland Brain Institute was supported by the Australian Research Council (LE100100074).
CitationCereb Cortex, 2018, 28 (7), pp. 2340-2350
Author affiliation/Organisation/COLLEGE OF LIFE SCIENCES/Biological Sciences/Neuroscience, Psychology and Behaviour
- AM (Accepted Manuscript)