DIFFERENT FORMS OF IMPAIRMENT OF THE FORE-HINDLIMB COORDINATION AFTERPARTIAL SPINAL LESIONS IN CATS

Effects of large low thoracic (T10-T11) partial spinal lesions involvi ng either the ventral quadrants of the spinal cord and, to a different extent the dorsolateral funiculi, or different extent of the lateral funiculi and/or the dorsal columns, on the fore-hindlimb coordination were examined in cats walking overground at moderate speeds. In both g roups of operated cats, except those in which the lesion was essential ly confined to dorsal columns, three different forms of impairment of fore-hindlimb coordination were observed, depending on the extent of l esion: (1) a change of locomotion towards pacing with preservation of the equality of rhythms in the fore- and the hindlimbs; (2) episodes o f fore- and hindlimb rhythm dissociation and (3) a permanent dissociat ion of the fore- and hindlimb rhythms. A comparison of the results obt ained in these two groups of operated cats points to the more importan t role played by the lateral funiculi, than by other parts of the spin al white matter, in controlling the fore-hindlimb coordination in cats .