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Free keywords:
barrel cortex, pyramidal tract neurons, corticocortical neurons, synchrony, in silico
Abstract:
Pyramidal tract neurons (PTs) represent the major output cell type of the mammalian neocortex. Here, we report the origins of the PTs’ ability to respond to a broad range of stimuli with onset latencies that rival or even precede those of their intracortical input neurons. We find that neurons with extensive horizontally projecting axons cluster around the deep-layer terminal fields of primary thalamocortical axons. The strategic location of these corticocortical neurons results in high convergence of thalamocortical inputs, which drive reliable sensory-evoked responses that precede those in other excitatory cell types. The resultant fast and horizontal stream of excitation provides PTs throughout the cortical area with input that acts to amplify additional inputs from thalamocortical and other intracortical populations. The fast onsets and broadly tuned characteristics of PT responses hence reflect a gating mechanism in the deep layers, which assures that sensory-evoked input can be reliably transformed into cortical output.
Abstract:
In Brief:
Egger, Narayanan, et al. describe the cellular and circuit mechanisms underlying the transformation of sensory-evoked thalamocortical input into fast and broadly tuned cortical output. The study provides a comprehensive multi-scale cortex model for studying streams of sensory-evoked excitationin silico.
