Increased expression of the growth-associated protein-43 gene after primary motor cortex lesion in macaque monkeys

• GAP-43 expression during functional recovery after M1 lesion was investigated.
• The expression increased in PMv especially during the period just after recovery.
• It increased in the perilesional M1 especially during the plateau phase of recovery.
• Results suggest time-dependent and brain region-specific remodeling during recovery.

We recently showed that changes of brain activity in the ipsilesional ventral premotor cortex (PMv) and perilesional primary motor cortex (M1) of macaque monkeys were responsible for recovery of manual dexterity after lesioning M1. To investigate whether axonal remodeling is associated with M1 lesion-induced changes in brain activity, we assessed gene expression of growth-associated protein-43 (GAP-43) in motor and premotor cortices. Increased expression was observed in the PMv during the period just after recovery and in the perilesional M1 during the plateau phase of recovery. Time-dependent and brain region-specific remodeling may play a role in functional recovery after lesioning M1.