Lamina IV-VI neurones of the second sacral segment projecting to the sixth cervical segment of the cat's spinal cord

Cervical projections of neurones located in the second sacral segment of the spinal cord were electrophysiologically investigated in 12 adult cats under alpha-chloralose anaesthesia. Extracellular or intracellular antidromic potentials from 41 neurons following stimulation of their axons in the spinal grey matter in the C6 segment brought evidence of sacro-cervical connections. Cell bodies of the investigated neurones were found mainly in the medial part of laminae IV, V and VI. Axons of these neurones ran in lateral funiculi, mostly in their dorsal parts (dlf). Most of the axons (26) ascended bilaterally. Fibres of 15 cells ran unilaterally--on the ipsilateral (13) or the contralateral side (2). Conduction velocities of axons measured between S2 and C6 segments were in the range from 38.4 to 69.1 m/s. It is suggested that these neurones may play an important role in movement coordination between hindlimbs and forelimbs.