title: Axonal sprouting and formation of terminals in the adult cerebellum during associative motor learning.
abstract: Plastic changes in the efficacy of synapses are widely regarded to represent mechanisms underlying memory formation. So far, evidence for learning-dependent, new neuronal wiring is limited. In this study, we demonstrate that pavlovian eyeblink conditioning in adult mice can induce robust axonal growth and synapse formation in the cerebellar nuclei. This de novo wiring is both condition specific and region specific because it does not occur in pseudoconditioned animals and is particularly observed in those parts of the cerebellar nuclei that have been implicated to be involved in this form of motor learning. Moreover, the number of new mossy fiber varicosities in these parts of the cerebellar nuclei is positively correlated with the amplitude of conditioned eyelid responses. These results indicate that outgrowth of axons and concomitant occurrence of new terminals may, in addition to plasticity of synaptic efficacy, contribute to the formation of memory.
authors.affiliation: Department of Neuroscience, Erasmus University Medical Center, 3000 DR Rotterdam, The Netherlands, and Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands.
authors.forename: Henk-Jan
authors.initials: HJ
authors.lastname: Boele
authors.forename: Sebastiaan K E
authors.initials: SK
authors.lastname: Koekkoek
authors.forename: Chris I
authors.initials: CI
authors.lastname: De Zeeuw
authors.forename: Tom J H
authors.initials: TJ
authors.lastname: Ruigrok
mesh_terms: D000818:Animals; D001245:Association Learning / Q000502:physiology*; D001369:Axons / Q000502:physiology*; D002531:Cerebellum / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000502:physiology; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000502:physiology*; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000502:physiology; D013569:Synapses / Q000502:physiology*