The Journal of Neuroscience, May 28, 2008, 28(22):5686-5690; doi:10.1523/JNEUROSCI.0584-08.2008
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Brief Communications
Transient Spine Expansion and Learning-Induced Plasticity in Layer 1 Primary Motor Cortex
Kimberly J. Harms, *
Mengia S. Rioult-Pedotti, *
D. Rosy Carter, and
Anna Dunaevsky
Department of Neuroscience, Brown University, Providence, Rhode Island 02912
Correspondence should be addressed to Anna Dunaevsky, Department of Neuroscience, Brown University, Box G-L459, 185 Meeting Street, Providence, RI 02912. Email: Anna_Dunaevsky{at}brown.edu
Experience-dependent regulation of synaptic strength in the horizontal connections in layer 1 of the primary motor cortex is likely to play an important role in motor learning. Dendritic spines, the primary sites of excitatory synapses in the brain, are known to change shape in response to various experimental stimuli. We used a rat motor learning model to examine connection strength via field recordings in slices and confocal imaging of labeled spines to explore changes induced solely by learning a simple motor task. We report that motor learning increases response size, while transiently occluding long-term potentiation (LTP) and increasing spine width in layer 1. This demonstrates learning-induced changes in behavior, synaptic responses, and structure in the same animal, suggesting that an LTP-like process in the motor cortex mediates the initial learning of a skilled task.
Key words: dendritic spines; motor cortex; layer 1; learning; LTP; field potentials
Received Feb. 8, 2008;
revised April 21, 2008;
accepted April 22, 2008.
Correspondence should be addressed to Anna Dunaevsky, Department of Neuroscience, Brown University, Box G-L459, 185 Meeting Street, Providence, RI 02912. Email: Anna_Dunaevsky{at}brown.edu