Synaptic connections in vitro: modulation of number and efficacy by electrical activity

Science  05 May 1989:
Vol. 244, Issue 4904, pp. 585-587
DOI: 10.1126/science.2717942


The functional architecture of synaptic circuits is determined to a crucial degree by the patterns of electrical activity that occur during development. Studies with an in vitro preparation of mammalian sensory neurons projecting to ventral spinal cord neurons slow that electrical activity induces competitive processes that regulate synaptic efficacy so as to favor activated pathways over inactive convergent pathways. At the same time, electrical activity initiates noncompetitive processes that increase the number of axonal connections between these sensory and spinal cord neurons.