Modality-specific thalamocortical inputs instruct the identity of postsynaptic L4 neurons
Nature. 2014-05-14; 511(7510): 471-474
DOI: 10.1038/nature13390
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1. Nature. 2014 Jul 24;511(7510):471-4. doi: 10.1038/nature13390. Epub 2014 May 14.
Modality-specific thalamocortical inputs instruct the identity of postsynaptic L4
neurons.
Pouchelon G(1), Gambino F(2), Bellone C(1), Telley L(1), Vitali I(1), Lüscher
C(3), Holtmaat A(1), Jabaudon D(3).
Author information:
(1)Department of Basic Neurosciences, Faculty of Medicine, University of Geneva,
CH-1211 Geneva, Switzerland.
(2)1] Department of Basic Neurosciences, Faculty of Medicine, University of
Geneva, CH-1211 Geneva, Switzerland [2] Interdisciplinary Institute for
NeuroScience, CNRS UMR 5297, 33077 Bordeaux, France.
(3)1] Department of Basic Neurosciences, Faculty of Medicine, University of
Geneva, CH-1211 Geneva, Switzerland [2] Clinic of Neurology, Department of
Clinical Neurosciences, Geneva University Hospital, CH-1211 Geneva, Switzerland
[3] Institute of Genetics & Genomics in Geneva (iGE3), University of Geneva,
CH-1211 Geneva, Switzerland.
During development, thalamocortical (TC) input has a critical role in the spatial
delineation and patterning of cortical areas, yet the underlying cellular and
molecular mechanisms that drive cortical neuron differentiation are poorly
understood. In the primary (S1) and secondary (S2) somatosensory cortex, layer 4
(L4) neurons receive mutually exclusive input originating from two thalamic
nuclei: the ventrobasalis (VB), which conveys tactile input, and the posterior
nucleus (Po), which conveys modulatory and nociceptive input. Recently, we have
shown that L4 neuron identity is not fully committed postnatally, implying a
capacity for TC input to influence differentiation during cortical circuit
assembly. Here we investigate whether the cell-type-specific molecular and
functional identity of L4 neurons is instructed by the origin of their TC input.
Genetic ablation of the VB at birth resulted in an anatomical and functional
rewiring of Po projections onto L4 neurons in S1. This induced acquisition of Po
input led to a respecification of postsynaptic L4 neurons, which developed
functional molecular features of Po-target neurons while repressing VB-target
traits. Respecified L4 neurons were able to respond both to touch and to noxious
stimuli, in sharp contrast to the normal segregation of these sensory modalities
in distinct cortical circuits. These findings reveal a behaviourally relevant
TC-input-type-specific control over the molecular and functional differentiation
of postsynaptic L4 neurons and cognate intracortical circuits, which instructs
the development of modality-specific neuronal and circuit properties during
corticogenesis.
DOI: 10.1038/nature13390
PMID: 24828045 [Indexed for MEDLINE]