title: Tactile Stimulation Evokes Long-Lasting Potentiation of Purkinje Cell Discharge In Vivo.
abstract: In the cerebellar network, a precise relationship between plasticity and neuronal discharge has been predicted. However, the potential generation of persistent changes in Purkinje cell (PC) spike discharge as a consequence of plasticity following natural stimulation patterns has not been clearly determined. Here, we show that facial tactile stimuli organized in theta-patterns can induce stereotyped N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA-A) receptor-dependent changes in PCs and molecular layer interneurons (MLIs) firing: invariably, all PCs showed a long-lasting increase (Spike-Related Potentiation or SR-P) and MLIs a long-lasting decrease (Spike-Related Suppression or SR-S) in baseline activity and spike response probability. These observations suggests that tactile sensory stimulation engages multiple long-term plastic changes that are distributed along the mossy fiber-parallel fiber (MF-PF) pathway and operate synergistically to potentiate spike generation in PCs. In contrast, theta-pattern electrical stimulation (ES) of PFs indistinctly induced SR-P and SR-S both in PCs and MLIs, suggesting that tactile sensory stimulation preordinates plasticity upstream of the PF-PC synapse. All these effects occurred in the absence of complex spike changes, supporting the theoretical prediction that PC activity is potentiated when the MF-PF system is activated in the absence of conjunctive climbing fiber (CF) activity.
authors.affiliation: Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Consorzio Interuniversitario per le Scienze Fisiche della Materia (CNISM)Pavia, Italy.
authors.forename: K B
authors.initials: KB
authors.lastname: Ramakrishnan
authors.affiliation: Department of Neuroscience, Erasmus University Rotterdam Rotterdam, Netherlands.
authors.forename: Kai
authors.initials: K
authors.lastname: Voges
authors.affiliation: Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy.
authors.forename: Licia
authors.initials: L
authors.lastname: De Propris
authors.affiliation: Department of Neuroscience, Erasmus University RotterdamRotterdam, Netherlands; Netherlands Institute for Neuroscience, Royal Academy of Arts and SciencesAmsterdam, Netherlands.
authors.forename: Chris I
authors.initials: CI
authors.lastname: De Zeeuw
authors.affiliation: Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy; Brain Connectivity Center, Istituto Neurologico IRCCS Fondazione C. MondinoPavia, Italy.
authors.forename: Egidio
authors.initials: E
authors.lastname: D'Angelo
keywords: LTD; LTP; Purkinje cell; cerebellum; in vivo electrophysiology; molecular layer interneurons; suppression