A Transient Translaminar GABAergic Interneuron Circuit Connects Thalamocortical Recipient Layers in Neonatal Somatosensory Cortex.

Marques-Smith A., Lyngholm D., Kaufmann A-K., Stacey JA., Hoerder-Suabedissen A., Becker EBE., Wilson MC., Molnár Z., Butt SJB.

GABAergic activity is thought to influence developing neocortical sensory circuits. Yet the late postnatal maturation of local layer (L)4 circuits suggests alternate sources of GABAergic control in nascent thalamocortical networks. We show that a population of L5b, somatostatin (SST)-positive interneuron receives early thalamic synaptic input and, using laser-scanning photostimulation, identify an early transient circuit between these cells and L4 spiny stellates (SSNs) that disappears by the end of the L4 critical period. Sensory perturbation disrupts the transition to a local GABAergic circuit, suggesting a link between translaminar and local control of SSNs. Conditional silencing of SST+ interneurons or conversely biasing the circuit toward local inhibition by overexpression of neuregulin-1 type 1 results in an absence of early L5b GABAergic input in mutants and delayed thalamic innervation of SSNs. These data identify a role for L5b SST+ interneurons in the control of SSNs in the early postnatal neocortex.

DOI

10.1016/j.neuron.2016.01.015

Type

Journal article

Journal

Neuron

Publication Date

03/02/2016

Volume

89

Pages

536 - 549

Keywords

Animals, Electric Stimulation, Female, Interneurons, Male, Membrane Potentials, Mice, Mice, Transgenic, Neural Pathways, Neuregulin-1, Photic Stimulation, Somatosensory Cortex, Somatostatin, Thalamus, gamma-Aminobutyric Acid

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