Graded Control of Climbing-Fiber-Mediated Plasticity and Learning by Inhibition in the Cerebellum Rowan, Matthew J.M. et al. Neuron, Volume 99, Issue 5, 999 - 1015.e6
Abstract:
Purkinje cell dendrites convert excitatory climbing fiber input into signals that instruct plasticity and motor learning. Modulation of instructive signaling may increase the range in which learning is encoded, yet the mechanisms that allow for this are poorly understood. We found that optogenetic activation of molecular layer interneurons (MLIs) that inhibit Purkinje cells suppressed climbing-fiber-evoked dendritic Ca2+ spiking. Inhibitory suppression of Ca2+ spiking depended on the level of MLI activation and influenced the induction of associative synaptic plasticity, converting climbing-fiber-mediated potentiation of parallel fiber-evoked responses into depression. In awake mice, optogenetic activation of floccular climbing fibers in association with head rotation produced an adaptive increase in the vestibulo-ocular reflex (VOR). However, when climbing fibers were co-activated with MLIs, adaptation occurred in the opposite direction, decreasing the VOR. Thus, MLIs can direct a continuous spectrum of plasticity and learning through their influence on Purkinje cell dendritic Ca2+ signaling.
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Funding Info:
This work was supported by the Singapore Ministry of Education grant MOE2016-T2-1-097 (G.J.A.) as well as the Max Planck Society , the Max Planck Florida Institute for Neuroscience , and NIH grants NS083127 (M.J.M.R.) and NS083894 (J.M.C.).
Description:
The full paper is available for download at the publisher's URL: https://doi.org/10.1016/j.neuron.2018.07.024