OLFACTORY EVOKED-POTENTIAL PRODUCED BY ELECTRICAL-STIMULATION OF THE HUMAN OLFACTORY MUCOSA

Most physiological studies of the human olfactory system have concentr ated on the cortical level; the olfactory bulbar level has been studie d rarely. We attempted to stimulate the human olfactory mucosa by elec trical pulse to detect the bulbar potentials. Electrical stimulation ( 2 mA, 0.5 ms) of the human olfactory mucosa evoked a change in potenti al recorded from the frontal sector of the head. A negative peak of th e evoked potential that occurred at 19.4 ms (grand means, n = 5) after stimulation was the dearest. The highest amplitude of the potential w as recorded from the frontal sector of the head on the stimulated side . Our findings were similar to the experimental results obtained from the olfactory bulbs of animals. This evoked potential was considered t o be the human olfactory bulbar potential. When the subjects were stim ulated by applying electricity to the olfactory mucosa, no sensation o f smell occurred even though evoked potentials were recorded. Evoked p otentials were recorded only when the stimulating electrode was locate d in the olfactory cleft. When the stimulating electrode was outside t he olfactory cleft, the stimulation caused pain. The trigeminal nerve seemed to be stimulated by electricity. Olfactory evoked potentials pr oduced by the electrical stimulation of the human olfactory mucosa sho uld aid the research on human olfactory physiology, and may be applica ble to clinical tests of olfactory dysfunction.