Neuronal Regulation Implements Efficient Synaptic Pruning

Abstract

Human and animal studies show that mammalian brain undergoes massive synaptic pruning during childhood , removing about half of the synapses until puberty. We have previously shown that main(cid:173) taining network memory performance while synapses are deleted, requires that synapses are properly modified and pruned, remov(cid:173) ing the weaker synapses. We now show that neuronal regulation , a mechanism recently observed to maintain the average neuronal in(cid:173) put field , results in weight-dependent synaptic modification . Under the correct range of the degradation dimension and synaptic up(cid:173) per bound, neuronal regulation removes the weaker synapses and judiciously modifies the remaining synapses . It implements near optimal synaptic modification, and maintains the memory perfor(cid:173) mance of a network undergoing massive synaptic pruning. Thus , this paper shows that in addition to the known effects of Hebbian changes, neuronal regulation may play an important role in the self-organization of brain networks during development.