Early onset of hindlimb paw-shake responses in spinal kittens: new perspective in motor development

Normal kittens and kittens spinalized (T12) at 14 days of age were tested for onset of paw-shake responses (PSR) in fore and hindlimbs. In normals, onset followed a cephalocaudal pattern that was coincident with the development of stable posture, 21-28 days of age. In spinals, onset of hindlimb PSRs preceded that of the forelimb and occurred soon after cordotomy, independent of posture development. These findings suggest that in the neonate, spinal networks responsible for coordinating PSRs are normally inhibited until the response can be supported by stable posture.