Yang Sunggu, Govindaiah Gubbi, Lee Sang-Hun, Yang Sungchil, Cox Charles L
Department of Nano-bioengineering, Incheon National University, Incheon, Korea.
Department of Molecular & Integrative Physiology, University of Illinois, Urbana, Illinois, United States of America.
PLoS One. 2017 Dec 18;12(12):e0189690. doi: 10.1371/journal.pone.0189690. eCollection 2017.
Thalamocortical neurons in the dorsal lateral geniculate nucleus (dLGN) transfer visual information from retina to primary visual cortex. This information is modulated by inhibitory input arising from local interneurons and thalamic reticular nucleus (TRN) neurons, leading to alterations of receptive field properties of thalamocortical neurons. Local GABAergic interneurons provide two distinct synaptic outputs: axonal (F1 terminals) and dendritic (F2 terminals) onto dLGN thalamocortical neurons. By contrast, TRN neurons provide only axonal output (F1 terminals) onto dLGN thalamocortical neurons. It is unclear if GABAA receptor-mediated currents originating from F1 and F2 terminals have different characteristics. In the present study, we examined multiple characteristics (rise time, slope, halfwidth and decay τ) of GABAA receptor-mediated miniature inhibitory postsynaptic synaptic currents (mIPSCs) originating from F1 and F2 terminals. The mIPSCs arising from F2 terminals showed slower kinetics relative to those from F1 terminals. Such differential kinetics of GABAAR-mediated responses could be an important role in temporal coding of visual signals.
背外侧膝状核（dLGN）中的丘脑皮质神经元将视觉信息从视网膜传递到初级视觉皮层。该信息受到来自局部中间神经元和丘脑网状核（TRN）神经元的抑制性输入的调节，从而导致丘脑皮质神经元感受野特性的改变。局部GABA能中间神经元在dLGN丘脑皮质神经元上提供两种不同的突触输出：轴突（F1终末）和树突（F2终末）。相比之下，TRN神经元仅在dLGN丘脑皮质神经元上提供轴突输出（F1终末）。源自F1和F2终末的GABAA受体介导的电流是否具有不同的特性尚不清楚。在本研究中，我们检查了源自F1和F2终末的GABAA受体介导的微小抑制性突触后突触电流（mIPSCs）的多个特性（上升时间、斜率、半高宽和衰减τ）。源自F2终末的mIPSCs相对于源自F1终末的mIPSCs表现出较慢的动力学。GABAAR介导反应的这种差异动力学可能在视觉信号的时间编码中起重要作用。
