Specific Functions of the Motor Cortex in Reorganizing Coordinations during Motor Training in Animals and Humans
Résumé
The involvement of the motor cortex in learning movements has recently attracted much attention. One
aspect of motor learning is the inhibition of innate synergies which interfere with performance of the
acquired movement. Various models of operant responses in dogs have demonstrated the critical role of
the motor cortex in the reorganization and inhibition of interfering synergies during learning. The role of
the motor cortex and corticospinal influences in the formation of new coordinations in humans was studied
here in patients with organic lesions of the cerebral circulation involving the internal capsule, using
postural coordination and movements in a bimanual unloading response as an example. Formation of the
forearm stabilization response was deeply lesioned on the afflicted side. Some degree of impairment was
also seen on the ipsilateral side, but it was no different from the level of learning impairment in patients
with lesions not involving the internal capsule or in patients with parkinsonism. The existence of specific
contralateral influences of the motor cortex and non-specific descending influences on the process of
motor learning is proposed.