Abstract
<title>Abstract</title> <p>Focal cortical injury induces large-scale network reorganisation involving remote disconnection and adaptive remodelling; however, the underlying connectional dynamics remain elusive. We investigated anatomical and functional dynamics within the macaque grasping circuit—comprising the primary motor cortex (M1), ventral premotor cortex (PMv), and anterior intraparietal area (AIP)—following M1 lesioning and recovery. Anatomical tracing demonstrated an anterior-to-posterior shift in PMv-intraparietal connectivity: canonical PMv–AIP projections were attenuated, while non-canonical PMv projections to the posterior segment of the ventral intraparietal area (pVIP), linked to proximal limb control, were reinforced. These shifts were paralleled by task-evoked activation: H₂¹⁵O-PET demonstrated declining regional cerebral blood flow (rCBF) in AIP and increasing rCBF in pVIP during precision grip. Hence, M1 injury disrupts PMv–M1 connectivity, undermining AIP-driven facilitation and reducing PMv–AIP connectivity. This loss may enable reinforcement of the longer pathway to pVIP, providing a framework for how robust motor recovery may emerge from limited remodelling of existing cortico-cortical connectivity.</p>