Deng Rongkang, Kao Joseph P Y, Kanold Patrick O
Department of Biology, University of Maryland, College Park, MD 20742, USA.
Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Cell Rep. 2017 May 9;19(6):1141-1150. doi: 10.1016/j.celrep.2017.04.044.
GABAergic activity is important in neocortical development and plasticity. Because the maturation of GABAergic interneurons is regulated by neural activity, the source of excitatory inputs to GABAergic interneurons plays a key role in development. We show, by laser-scanning photostimulation, that layer 4 and layer 5 GABAergic interneurons in the auditory cortex in neonatal mice (<P7) receive extensive translaminar glutamatergic input via NMDAR-only synapses. Extensive translaminar AMPAR-mediated input developed during the second postnatal week, whereas NMDAR-only presynaptic connections decreased. GABAergic interneurons showed two spatial patterns of translaminar connection: inputs originating predominantly from supragranular or from supragranular and infragranular layers, including the subplate, which relays early thalamocortical activity. Sensory deprivation altered the development of translaminar inputs. Thus, distinct translaminar circuits to GABAergic interneurons exist throughout development, and the maturation of excitatory synapses is input-specific. Glutamatergic signaling from subplate and intracortical sources likely plays a role in the maturation of GABAergic interneurons.
γ-氨基丁酸能（GABAergic）活动在新皮层发育和可塑性中起着重要作用。由于GABA能中间神经元的成熟受神经活动调节，因此GABA能中间神经元兴奋性输入的来源在发育中起关键作用。我们通过激光扫描光刺激表明，新生小鼠（<P7）听觉皮层中的第4层和第5层GABA能中间神经元通过仅含N-甲基-D-天冬氨酸受体（NMDAR）的突触接受广泛的跨层谷氨酸能输入。广泛的跨层α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPAR）介导的输入在出生后第二周出现，而仅含NMDAR的突触前连接减少。GABA能中间神经元表现出两种跨层连接的空间模式：输入主要来自颗粒上层或颗粒上层和颗粒下层，包括中继早期丘脑皮质活动的板下带。感觉剥夺改变了跨层输入的发育。因此，在整个发育过程中存在到GABA能中间神经元的不同跨层回路，并且兴奋性突触的成熟是输入特异性的。来自板下带和皮质内来源的谷氨酸能信号可能在GABA能中间神经元的成熟中起作用。
