Robust learning-driven structural and functional plasticity of spines in the mature mouse cortex: Robust...

Spines in the adult cortex are thought to be highly stable, and that their capacity for modest remodeling supports learning. Using a visual association task and a multilevel imaging approach in adult mice, we found a robust learning-driven increase in the complexity of spine nanostructure, as well as a rapid and persistent increase in spine formation during task acquisition that were accompanied by an overall reduction in spine size of layer 2/3 neurons in the primary visual cortex (V1). Trained animals further had an increased fraction of spines tuned to the task-relevant orientations, and the discriminability of spine responses in naïve mice was predictive of their subsequent performance. Our results demonstrate that learning drives an increase in spine preferences for task-relevant information and point to reconfiguration of spine nanostructure and spine inputs as the structural drivers of these changes.