Center for Neural Science, New York University, New York, New York, USA.
J Neurophysiol. 2013 Aug;110(4):999-1008. doi: 10.1152/jn.00182.2013. Epub 2013 May 29.
Sensory deprivation, such as developmental hearing loss, leads to an adjustment of synaptic and membrane properties throughout the central nervous system. These changes are thought to compensate for diminished sound-evoked activity. This model predicts that compensatory changes should be synergistic with one another along each functional pathway. To test this idea, we examined the excitatory thalamic drive to two types of cortical inhibitory interneurons that display differential effects in response to developmental hearing loss. The inhibitory synapses made by fast-spiking (FS) cells are weakened by hearing loss, whereas those made by low threshold-spiking (LTS) cells remain strong but display greater short-term depression (Takesian et al. 2010). Whole-cell recordings were made from FS or LTS interneurons in a thalamocortical brain slice, and medial geniculate (MG)-evoked postsynaptic potentials were analyzed. Following hearing loss, MG-evoked net excitatory potentials were smaller than normal at FS cells but larger than normal at LTS cells. Furthermore, MG-evoked excitatory potentials displayed less short-term depression at FS cells and greater short-term depression at LTS cells. Thus deprivation-induced adjustments of excitatory synapses onto inhibitory interneurons are cell-type specific and parallel the changes made by the inhibitory afferents.
感觉剥夺，例如发育性听力损失，会导致整个中枢神经系统的突触和膜特性发生调整。这些变化被认为是对减弱的声音诱发活动的补偿。该模型预测，补偿性变化应该在每个功能途径上彼此协同。为了检验这一想法，我们研究了两种类型的皮质抑制性中间神经元的兴奋性丘脑驱动，这些中间神经元对发育性听力损失的反应存在差异。快速放电（FS）细胞形成的抑制性突触因听力损失而减弱，而由低阈值放电（LTS）细胞形成的抑制性突触仍然很强，但表现出更大的短期抑郁（Takesian 等人，2010）。在丘脑皮质脑切片中，从 FS 或 LTS 中间神经元进行全细胞记录，并分析内侧膝状体（MG）诱发的突触后电位。听力损失后，与正常情况相比，MG 诱发的 net 兴奋性电位在 FS 细胞中较小，但在 LTS 细胞中较大。此外，MG 诱发的兴奋性电位在 FS 细胞中表现出较小的短期抑郁，而在 LTS 细胞中表现出较大的短期抑郁。因此，剥夺诱导的兴奋性突触对抑制性中间神经元的调整是细胞类型特异性的，并与抑制性传入的变化平行。
