Field distribution of antidromically activated digital nerve potentials: model for far-field recording.

In 20 median nerves, the shift in mean latency of the referentially recorded antidromic sensory potential was 0.22 to 0.38 msec per 1.5 cm across the palm and only 0.03 to 0.05 msec per 1.5 cm along the third digit. In five radial nerves, referential recording from the tip of the second digit detected a stationary positive potential that was coincident with the entry of the sensory impulse into the nerve terminal near the base of the digit. These findings are consistent with the view that, in far-field recording of a traveling impulse, a time peak could result from an abrupt change in current flow that is based on the geometry of the volume conductor without fixed neural discharges.