Cortical Synaptic AMPA Receptor Plasticity during Motor Learning

Modulation of synaptic strength through trafficking of AMPA receptors (AMPARs) is a fundamental mechanism underlying synaptic plasticity, learning, and memory. However, the dynamics of AMPAR trafficking in vivo and its correlation with learning have not been resolved. Here, we used in vivo two-photon microscopy to visualize surface AMPARs in mouse cortex during the acquisition of a forelimb reaching task. Daily training leads to an increase in AMPAR levels at a subset of spatially clustered dendritic spines in the motor cortex. Surprisingly, we also observed increases in spine AMPAR levels in the visual cortex. There, synaptic potentiation depends on the availability of visual input during motor training, and optogenetic inhibition of visual cortex activity impairs task performance. These results indicate that motor learning induces widespread cortical synaptic potentiation by increasing the net trafficking of AMPARs into spines, including in non-motor brain regions. •In vivo imaging of AMPA receptors reveals high dynamics at individual synapses•Motor learning induces potentiation of a clustered subset of dendritic spines•Motor learning increases AMPA receptor levels in motor and visual cortex•Plasticity of visual cortex during learning depends on visual input Through in vivo imaging of synaptic AMPA receptors in mice, Roth et al. show that motor learning potentiates synapses in both motor and visual cortex. Recruitment and potentiation of the visual cortex require visual stimuli during motor training.