Figure 1:

Dendritic spine plasticity- a substrate for motor learning and motor recovery after stroke. Left panel- Motor learning in rodents such as skilled reaching to grab food pellets forces changes on post-synaptic structures on dendrites called spines. These changes occur in motor cortex (M1). Changes include addition of new spines (red) and clustering of spines that lead to strengthened synaptic inputs. Right panel- After stroke, there is loss of synaptic connectivity, particularly near the infarct (peri-infarct tissue). Rehabilitation, spontaneous motor recovery or genetic manipulations such as with CCR5 knockdown induces similar changes on spines as reported with motor learning in the normal brain.