Sculpting neuronal connectivity

摘要

Experiences trigger long-lasting changes in memory and behaviour. Although manifested at the organismal level, such changes arise from modifications of individual synaptic connections between neurons. Specifically, new sensory experiences alter a neuron's activity (its output of action potentials) by modulating the strength of the synaptic connections that it receives. On page 121 of this issue, Bloodgood et al. demonstrate that a transcriptional program drives highly localized changes in synaptic connections between neurons. The authors' results thus offer a refined molecular explanation for experience-dependent learning processes. When an animal explores an uncharted environment, neural activity originating from its sensory organs propagates into the brain, where neurons receive a barrage of concurrent excitatory and inhibitory inputs. The net activity signal that each neuron receives is determined by a delicate balance of these two competing forces. In some neurons, excitation prevails and the cells produce an action-potential spike; in others, inhibition overrides excitation and the cells remain silent.