title: Motor skill training induces coordinated strengthening and weakening between neighboring synapses.
abstract: Motor skill training promotes the formation of parallel fiber multiple-synapse boutons (MSBs) contacting dendritic spine pairs of Purkinje cells in the rat cerebellum. However, the dendritic origin of such spine pairs is unknown. Here, we used three-dimensional electron microscopy reconstruction of synaptic connectivity to demonstrate that motor skill training selectively induced MSBs contacting two spines arising from the same dendrite, consistent with strengthening of local synaptic efficacy. However, excitatory synapses near MSBs were smaller in motor-trained animals, suggesting compensatory depression of MSB-neighbor synapses. Concerted strengthening and weakening of adjacent synapses may enhance synaptic weight differences for information encoding while maintaining stable overall activity levels within local dendritic segments.
authors.affiliation: Department of Anatomy, Korea University College of Medicine, Sungbuk-Gu, Seoul 136-705, Korea.
authors.forename: Kea Joo
authors.initials: KJ
authors.lastname: Lee
authors.forename: In Sung
authors.initials: IS
authors.lastname: Park
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.forename: William T
authors.initials: WT
authors.lastname: Greenough
authors.forename: Daniel T S
authors.initials: DT
authors.lastname: Pak
authors.forename: Im Joo
authors.initials: IJ
authors.lastname: Rhyu
mesh_terms: D000818:Animals; D007858:Learning / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure*