The effect of ischemia on the peripheral nerve action potential in man and its relation to somatosensory magnitude coding

The amplitude and latency fluctuations of the compound action potential of the ulnar nerve were recorded percutaneously as a function of the length of time the arm was kept ischemic by means of an inflated sphygmomanometer cuff. Changes in latency and the amplitude action potential were measured for cuff positions above and below the recording electrode. The amplitude fluctuations were shown to be related to corresponding changes in the sensory threshold which has been determined in an earlier study. By manipulating the position of the cuff it was possible to determine that the amplitude fluctuations were caused by a reduced number of nerve action potentials rather than a change in the individual atonal action potential amplitude.