Conserved role of primary motor cortex in the control of prehension in mice and macaques

A central goal in neuroscience is to develop cross-species frameworks that reveal conserved principles of movement control. Recent work has suggested a potential species difference in the role of primary motor cortex (M1) during skilled forelimb tasks: in rodents, extensive practice appears to shift control to subcortical circuits, leading to "disengagement" of M1 from task execution. Importantly, there is no evidence of such disengagement in macaques. We hypothesized that these differences instead reflect task demands, particularly the need for fine (i.e., grasping) versus gross motor control. Strikingly, M1 lesions in macaques produced recovery patterns similar to rodents: gross motor control, including an exclusively gross motor task, recovered rapidly, whereas fine motor control exhibited persistent deficits. Detailed kinematic analyses in both macaques and mice performing a single-pellet reach-to-grasp task (RGT) revealed analogous disruptions in the temporal structure of sub-movements. These findings underscore the importance of task design and the translational value of rodent models for understanding motor control and recovery.