Reig Ramon, Gallego Roberto, Nowak Lionel G, Sanchez-Vives Maria V
Instituto de Neurociencias de Alicante, Universidad Miguel Hernandez-CSIC, Apartado 18, 03550 San Juan de Alicante, Spain and.
Cereb Cortex. 2006 May;16(5):688-95. doi: 10.1093/cercor/bhj014. Epub 2005 Aug 17.
Repetitive stimulation of synaptic connections in the cerebral cortex often induces short-term synaptic depression (STD), a property directly related to the probability of transmitter release and critical for the computational properties of the network. In order to explore how spontaneous activity in the network affects this property, we first studied STD in cortical slices that were either silent or that displayed spontaneous rhythmic slow oscillations resembling those recorded during slow wave sleep in vivo. STD was considerably reduced by the occurrence of spontaneous rhythmic activity in the cortical network. Once the rhythmic activity started, depression decreased over time in parallel with the duration and intensity of the ongoing activity until a plateau was reached. Thalamocortical and intracortical synaptic potentials studied in vivo also showed stronger depression in a silent than in an active cortical network, and the depression values in the active cortical network in vivo were indistinguishable from those found in active slices in vitro. We suggest that this phenomenon is due to the different steady states of the synapses in active and in silent networks.
大脑皮层中突触连接的重复刺激常常会诱发短期突触抑制（STD），这一特性与神经递质释放的概率直接相关，并且对神经网络的计算特性至关重要。为了探究网络中的自发活动如何影响这一特性，我们首先研究了处于静息状态或表现出自发节律性慢振荡（类似于在体内慢波睡眠期间记录到的振荡）的皮层切片中的STD。皮层网络中自发节律性活动的出现使STD显著降低。一旦节律性活动开始，抑制作用会随着持续活动的持续时间和强度而随时间下降，直至达到平稳状态。在体内研究的丘脑皮质和皮质内突触电位也显示，在静息的皮层网络中比在活跃的皮层网络中表现出更强的抑制作用，并且体内活跃皮层网络中的抑制值与体外活跃切片中的抑制值没有区别。我们认为这种现象是由于活跃网络和静息网络中突触的不同稳态所致。
