title: Synapse efficiency diverges due to synaptic pruning following overgrowth.
abstract: In the development of the brain, it is known that synapses are pruned following overgrowth. This pruning following overgrowth seems to be a universal phenomenon that occurs in almost all areas-visual cortex, motor area, association area, and so on. It has been shown numerically that the synapse efficiency is increased by systematic deletion. We discuss the synapse efficiency to evaluate the effect of pruning following overgrowth, and analytically show that the synapse efficiency diverges as O(|ln c|) at the limit where connecting rate c is extremely small. Under a fixed synapse number criterion, the optimal connecting rate, which maximizes memory performance, exists.
authors.affiliation: Department of Electrical Engineering, Kobe City College of Technology, Gakuenhigashi-machi 8-3, Nishi-ku, Kobe, Hyogo 651-2194, Japan. mimura@kobe-kosen.ac.jp
authors.forename: Kazushi
authors.initials: K
authors.lastname: Mimura
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kimoto
authors.forename: Masato
authors.initials: M
authors.lastname: Okada
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D001921:Brain / Q000502:physiology*; D006801:Humans; D008568:Memory; D015233:Models, Statistical; D009415:Nerve Net; D013569:Synapses / Q000473:pathology* / Q000502:physiology*