Transient spine expansion and learning-induced plasticity in layer 1 primary motor cortex.
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.
Department of Neuroscience, Brown University, Providence, Rhode Island 02912, USA.
Kimberly J
KJ
Harms
Mengia S
MS
Rioult-Pedotti
D Rosy
DR
Carter
Anna
A
Dunaevsky
D000596:Amino Acids; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D049229:Dendritic Spines / Q000502:physiology* / Q000648:ultrastructure*; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D030762:Estrous Cycle / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D007858:Learning / Q000502:physiology*; D017774:Long-Term Potentiation / Q000502:physiology / Q000528:radiation effects; D018613:Microscopy, Confocal / Q000379:methods; D009044:Motor Cortex / Q000502:physiology* / Q000648:ultrastructure*; D009048:Motor Skills / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000596:Amino Acids; C098463:dolaisoleucine