Effects of unilateral somatosensory cortex lesion upon locomotion in dogs

Locomotive limb movements were studied in 6 dogs before and after unilateral (right) primary somatosensory cortex (SI) lesion. Single limb movement parameters as well as interlimb coordination in lesioned dogs differed significantly from the parameters measured before surgery. Both left limbs showed a proprioceptive deficit and were more flexed during normal posture and during locomotion. This resulted in prolonged stance in the left fore and in the right hind legs. The symptoms were greatly pronounced in the left fore limb compared to a slightly impaired left hindlimb. Due to the proprioceptive deficit, the dogs did not have satisfactory control over the position of the distal part of the front limb which caused frequent stumbling and even falling. The symptoms were transient and fully compensated after 3-4 weeks.