ODORANT EVOKED MAGNETIC-FIELDS IN HUMANS

We investigated the olfactory evoked magnetic fields (OEFs) in 14 norm al subjects. Pulses of odorant air containing amyl acetate or phenethy l alcohol, and odorless air were administered to the subject through a nasal tube. A clear and consistent OEF component, 1M, was identified in all subjects, and a second component, 2M, was detected in seven sub jects, but no consistent component was identified in response to the o dorless air. The peak latencies of the 1M and 2M components were appro ximately 320 and 630 ms, respectively. The waveforms produced by the o dorless air were subtracted from the waveforms produced by the odorant air to obtain the 'subtraction' waveform, which indicated the 1M and 2M component more clearly. Their equivalent current dipoles (ECDs) wer e estimated in the regions around the Sylvian fissure symmetrically in both hemispheres. Therefore, these areas are proposed to be involved in olfactory perception in humans. (C) 1997 Elsevier Science Ireland L td.