Estimation of conduction velocity in bulbospinal excitatory pathways to sympathetic outflows in cat spinal cord.

Experiments were performed on cats to measure the conduction velocity of the bulbospinal sympatho-excitatory axons. The lateral white matter of the cervical spinal cord and regions of the medulla were systematically explored for sympatho-excitatory points whilst recording from two sympathetic preganglionic outflows simultaneously. These were chosen a suitable distance apart to give a clear difference in latency to enable precise calculation of axonal conduction velocity between the two outflows. In addition, in a few cases conduction velocity was also measured by determining the latency shift of evoked responses, resulting from moving the stimulating electrode a known distance closer to the recording site. Conduction velocities of sympatho-excitatory axons in the spinal cord determined by these two procedures lay in the range 1.6-7.9 m/s.