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

Area of Science:

• Neuroscience
• Motor control research
• Molecular biology

Background:

• Functional recovery after primary motor cortex (M1) lesions involves brain activity changes in the ventral premotor cortex (PMv) and perilesional M1.
• The role of axonal remodeling in these recovery processes remains unclear.

Purpose of the Study:

• To investigate the association between axonal remodeling and M1 lesion-induced brain activity changes.
• To determine if gene expression related to axonal growth correlates with functional recovery of manual dexterity.

Main Methods:

• Gene expression of growth-associated protein-43 (GAP-43) was assessed in motor and premotor cortices of macaque monkeys following M1 lesions.
• Expression levels were analyzed in relation to the recovery phase of manual dexterity.

Main Results:

• Increased GAP-43 expression was observed in the ventral premotor cortex (PMv) shortly after functional recovery.
• Elevated GAP-43 expression was detected in the perilesional primary motor cortex (M1) during the plateau phase of recovery.

Conclusions:

• Time-dependent and brain region-specific axonal remodeling, evidenced by GAP-43 expression, likely contributes to functional recovery after M1 lesions.
• These findings highlight the dynamic nature of neural plasticity in motor cortex repair.