Department of Anatomy, Korea University College of Medicine, Sungbuk-Gu, Seoul 136-705, Korea.
J Neurosci. 2013 Jun 5;33(23):9794-9. doi: 10.1523/JNEUROSCI.0848-12.2013.
Motor skill training promotes the formation of parallel fiber multiple-synapse boutons (MSBs) contacting dendritic spine pairs of Purkinje cells in the rat cerebellum. However, the dendritic origin of such spine pairs is unknown. Here, we used three-dimensional electron microscopy reconstruction of synaptic connectivity to demonstrate that motor skill training selectively induced MSBs contacting two spines arising from the same dendrite, consistent with strengthening of local synaptic efficacy. However, excitatory synapses near MSBs were smaller in motor-trained animals, suggesting compensatory depression of MSB-neighbor synapses. Concerted strengthening and weakening of adjacent synapses may enhance synaptic weight differences for information encoding while maintaining stable overall activity levels within local dendritic segments.
运动技能训练促进大鼠小脑浦肯野细胞树突棘对平行纤维多突触末梢（MSB）的形成。然而，这些树突棘对的起源尚不清楚。本研究应用突触连接的三维电子显微镜重建，证明运动技能训练选择性诱导与同一树突上两个棘突接触的 MSB，这与局部突触效能的增强一致。然而，运动训练动物的 MSB 附近的兴奋性突触较小，提示 MSB 邻近突触的代偿性抑制。相邻突触的协同增强和减弱可能增强信息编码的突触权重差异，同时保持局部树突段内的整体活动水平稳定。
