Froemke Robert C, Merzenich Michael M, Schreiner Christoph E
Coleman Memorial Laboratory and W. M. Keck Foundation Center for Integrative Neuroscience, Department of Otolaryngology, University of California, San Francisco, California 94143, USA.
Nature. 2007 Nov 15;450(7168):425-9. doi: 10.1038/nature06289.
Receptive fields of sensory cortical neurons are plastic, changing in response to alterations of neural activity or sensory experience. In this way, cortical representations of the sensory environment can incorporate new information about the world, depending on the relevance or value of particular stimuli. Neuromodulation is required for cortical plasticity, but it is uncertain how subcortical neuromodulatory systems, such as the cholinergic nucleus basalis, interact with and refine cortical circuits. Here we determine the dynamics of synaptic receptive field plasticity in the adult primary auditory cortex (also known as AI) using in vivo whole-cell recording. Pairing sensory stimulation with nucleus basalis activation shifted the preferred stimuli of cortical neurons by inducing a rapid reduction of synaptic inhibition within seconds, which was followed by a large increase in excitation, both specific to the paired stimulus. Although nucleus basalis was stimulated only for a few minutes, reorganization of synaptic tuning curves progressed for hours thereafter: inhibition slowly increased in an activity-dependent manner to rebalance the persistent enhancement of excitation, leading to a retuned receptive field with new preference for the paired stimulus. This restricted period of disinhibition may be a fundamental mechanism for receptive field plasticity, and could serve as a memory trace for stimuli or episodes that have acquired new behavioural significance.
感觉皮层神经元的感受野具有可塑性，会随着神经活动或感觉经验的改变而变化。通过这种方式，感觉环境的皮层表征可以根据特定刺激的相关性或价值纳入有关世界的新信息。皮层可塑性需要神经调节，但尚不清楚诸如胆碱能基底核等皮层下神经调节系统如何与皮层回路相互作用并对其进行优化。在这里，我们使用体内全细胞记录来确定成年初级听觉皮层（也称为AI）中突触感受野可塑性的动态变化。将感觉刺激与基底核激活配对，通过在几秒钟内快速降低突触抑制，随后大幅增加兴奋性，这两者都针对配对刺激，从而改变了皮层神经元的偏好刺激。尽管仅刺激基底核几分钟，但此后突触调谐曲线的重组持续了数小时：抑制以活动依赖的方式缓慢增加，以重新平衡持续增强的兴奋性，导致感受野重新调整，对配对刺激产生新的偏好。这种有限的去抑制期可能是感受野可塑性的基本机制，并可作为对具有新行为意义的刺激或事件的记忆痕迹。
