Axonal conduction velocity and perikaryal size

The recent identification of brisk-transient units with alpha cells in the cat's retina provided a direct opportunity to test the widely held belief that larger cells give rise to larger axons, and smaller to smaller. Alpha-cell perikarya increase substantially in size over the first 2 mm from the center of the area centralis. In one cat a map was obtained of the receptivefield centers of all brisk-transient units in the region of the area centralis together with their antidromic latencies to optic tract stimulation. The map was then brought into approximate register with a map of all the alpha cells of the region. The correspondence was controlled by the placement and subsequent identification of electrolytic lesions. Thus perikaryal size could be rather directly compared with axonal conduction latency. The expected relation was verified under singularly uniform circumstances.