Cervical and cerebellar projections of lamina VII and VIII neurones of the S2 segment in the cat's spinal cord.

Dual projections to the sixth cervical segment and to the cerebellum were electrophysiologically investigated in neurones from the second sacral segment of the spinal cord in cats under chloralose anaesthesia. 49 neurones were antidromically identified following stimulation of the ipsilateral and contralateral spinal gray matter of the C6 segment and the contralateral inferior cerebellar peduncle (coRB), 28 of the total sample projected to the C6 bilaterally, 17 contralaterally and 4 ipsilaterally. 24 neurones of bilateral or contralateral projection to the C6 could be additionally activated from the coRB. The cells were distributed in Rexed's laminae VII and VIII with neurones projecting to the cerebellum located more medially. Conduction velocities of axons ascending in lateral funiculi were comprised in the range 42-96 m/s and the decrease was observed in some cases when compared distal and proximal parts of axons. No differences were found when compared values for neurones with or without cerebellar projection. It is suggested that both propriospinal and supraspinal projections of the investigated neurones take part in hindlimb-forelimb coordination.