Antidromic Activation of Renshaw Cells and their Axonal Projections

Antidromic invasion of Renshaw cells following stimulation of their axons was found always to produce only a single spike in contrast to repetitive synaptic discharges. A systematic exploration of the spinal cord in a search for sites from which single Renshaw cells could be activated antidromically revealed that their axons: 1) can project to distances over 12 mm, 2) run in the ventral funiculus. 3) are likely to terminate both within motor nuclei (mainly at short distances) and in an area dorso‐medial and medial to them, and 4) have a maximal conduction velocity of about 30 mls.