Motor learning-induced multiple synapse formation in the cerebellum: 3-D electron microscopy

Abstract

Event Abstract Back to Event Motor learning-induced multiple synapse formation in the cerebellum: 3-D electron microscopy Kea Joo Lee1* 1 Korea Brain Research Institute, Department of Structure & Function of Neural Network, Korea, South Experience-dependent synapse remodeling is considered a cellular mechanism of memory formation in the brain. Although accumulating evidence suggests synergistic roles of long-term depression and long-term potentiation in cerebellar motor learning, their morphological correlates and operational mechanisms have not yet been determined. Here we have investigated this issue at parallel fiber-to-Purkinje cell (PF-PC) synapses in cerebella of rats trained in a complex motor skill task using multiple types of electron microscopy. High-voltage electron microscopy of PC spine density and shape showed that motor skill trained rats had more spines with thin shape along the distal dendrites compared to their active or inactive controls. To examine which type of PF-PC synapses was altered following motor skill learning, PF-PC synapses were classified into single-synapse boutons (SSBs), multiple-synapse boutons (MSBs), and multiple-synapse spines (MSSs) by their distinct contact features. Motor skill training promoted the formation of SSBs as well as MSBs contacting dendritic spine pairs of PCs in the rat cerebellum. Because it is important to identify the dendritic origin of such spine pairs on MSBs for better understanding of cellular mechanisms of motor learning, we next employed serial section electron microscopy. 3-D reconstruction of MSBs demonstrated that motor skill training selectively induced MSBs contacting spine pairs originating from the same parent dendrite, consistent with strengthening of local synaptic efficacy. Interestingly, postsynaptic densities of excitatory synapses near MSBs were smaller in motor-trained animals, suggesting compensatory weakening of MSB-nearby synapses. This coordinated potentiation and depression of neighboring synapses may enhance synaptic weight differences for information encoding and represent morphological correlates of motor memory. To further investigate motor learning-induced remodeling of PF-PC synapses at a larger scale, we have employed automated serial block-face electron microscopy. This approach will generate invaluable information on how motor performance is refined in the cerebellar cortex. Keywords: Spines, dendritic, motor learning, synapse boutons, synapse remodelling Conference: 14th Meeting of the Asian-Pacific Society for Neurochemistry, Kuala Lumpur, Malaysia, 27 Aug - 30 Aug, 2016. Presentation Type: Symposium 1: Motor Control and Sensorimotor Integration: Circuitry and Plasticity Topic: 14th Meeting of the Asian-Pacific Society for Neurochemistry Citation: Lee K (2016). Motor learning-induced multiple synapse formation in the cerebellum: 3-D electron microscopy. Conference Abstract: 14th Meeting of the Asian-Pacific Society for Neurochemistry. doi: 10.3389/conf.fncel.2016.36.00006 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Jul 2016; Published Online: 11 Aug 2016. * Correspondence: Dr. Kea Joo Lee, Korea Brain Research Institute, Department of Structure & Function of Neural Network, Dong-gu, Deagu, Korea, South, relaylee@kbri.re.kr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Kea Joo Lee Google Kea Joo Lee Google Scholar Kea Joo Lee PubMed Kea Joo Lee Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.