Jones T A, Klintsova A Y, Kilman V L, Sirevaag A M, Greenough W T
Department of Psychology, Beckman Institute, University of Illinois, Urbana 61801, USA.
Neurobiol Learn Mem. 1997 Jul;68(1):13-20. doi: 10.1006/nlme.1997.3774.
This study examined experience effects upon the formation of multiple synaptic contacts among individual dendritic and axonal elements. Axonal boutons and dendritic spines forming contacts with more than one process were assessed within layer IV of the visual cortex in adult rats following 60 days of housing in standard laboratory cages (IC) or in complex environments (EC). Multiple synaptic boutons (MSBs) that formed synaptic contacts with both a dendritic spine and a dendritic shaft were found to be markedly increased in number per neuron in EC rats in comparison to those in IC rats. In contrast, single-synaptic contacts were not increased, indicating that the formation of new single-synaptic boutons is, at most, merely sufficient to replace boutons that may have been recruited into the population of MSBs. This apparent tendency to reutilize presynaptic processes may indicate a constraint upon the formation of neural circuitry and a fundamental form of plastic synaptic change.
本研究考察了经验对单个树突和轴突元件之间多个突触联系形成的影响。在成年大鼠视觉皮层IV层中，评估了与不止一个突起形成联系的轴突终扣和树突棘，这些大鼠分别在标准实验室笼子（IC）或复杂环境（EC）中饲养60天。与IC组大鼠相比，发现与树突棘和树突轴都形成突触联系的多个突触终扣（MSB）在EC组大鼠单个神经元中的数量显著增加。相比之下，单突触联系并未增加，这表明新的单突触终扣的形成最多仅足以替代可能已被纳入MSB群体的终扣。这种明显的重新利用突触前过程的趋势可能表明对神经回路形成的一种限制以及突触可塑性变化的一种基本形式。
