title: Synapse formation is associated with memory storage in the cerebellum.
abstract: The idea that memory is encoded by means of synaptic growth is not new. However, this idea has been difficult to demonstrate in the mammalian brain because of both the complexity of mammalian behavior and the neural circuitry by which it is supported. Here we examine how eyeblink classical conditioning affects synapse number within the cerebellum; the brain region essential for long-term retention of the conditioned response. Results showed eyeblink-conditioned rats to have significantly more synapses per neuron within the cerebellar interpositus nucleus than both explicitly unpaired and untrained controls. Further analysis showed that the increase was caused by the addition of excitatory rather than inhibitory synapses. Thus, development of the conditioned eyeblink response is associated with a strengthening of inputs from precerebellar nuclei rather than from cerebellar cortex. These results demonstrate that the modifications of specific neural pathways by means of synaptogenesis contributes to formation of a specific memory within the mammalian brain.
authors.affiliation: Canadian Centre for Behavioural Neuroscience, Department of Psychology and Neuroscience, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4. jeffrey.kleim@uleth.ca
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kleim
authors.forename: John H
authors.initials: JH
authors.lastname: Freeman
authors.forename: Rochelle
authors.initials: R
authors.lastname: Bruneau
authors.forename: Brian C
authors.initials: BC
authors.lastname: Nolan
authors.forename: Natalie R
authors.initials: NR
authors.lastname: Cooper
authors.forename: Alison
authors.initials: A
authors.lastname: Zook
authors.forename: Drew
authors.initials: D
authors.lastname: Walters
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001767:Blinking / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D002531:Cerebellum / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D008568:Memory; D009474:Neurons / Q000502:physiology; D051381:Rats; D013569:Synapses / Q000502:physiology*; D013997:Time Factors