Marques-Smith Andre, Lyngholm Daniel, Kaufmann Anna-Kristin, Stacey Jacqueline A, Hoerder-Suabedissen Anna, Becker Esther B E, Wilson Michael C, Molnár Zoltán, Butt Simon J B
Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK.
Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
Neuron. 2016 Feb 3;89(3):536-49. doi: 10.1016/j.neuron.2016.01.015.
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.
γ-氨基丁酸能（GABAergic）活动被认为会影响发育中的新皮质感觉回路。然而，局部第4层（L4）回路在出生后的后期成熟表明，新生丘脑皮质网络中存在GABA能控制的其他来源。我们发现，一群表达生长抑素（SST）的L5b阳性中间神经元接受早期丘脑突触输入，并通过激光扫描光刺激，确定了这些细胞与L4棘状星状神经元（SSNs）之间的早期短暂回路，该回路在L4关键期结束时消失。感觉扰动会破坏向局部GABA能回路的转变，这表明SSNs的跨层控制与局部控制之间存在联系。有条件地沉默SST+中间神经元，或者相反，通过过表达1型神经调节蛋白-1使回路偏向局部抑制，会导致突变体中早期L5b GABA能输入缺失，以及SSNs的丘脑神经支配延迟。这些数据确定了L5b SST+中间神经元在出生后早期新皮质中对SSNs控制的作用。
