Central odor processing in subjects experiencing helplessness.

The aim of the present study was to investigate whether central nervous odor processing is affected by the temporary experience of helplessness. To induce helplessness, an unsolvable social discrimination test in combination with false feedback was used. The EEG was recorded from 60 scalp locations, while two standard odors were presented via a constant-flow olfactometer. Helplessness attenuated olfactory stimulus processing at an early perceptual stage: the P2 and P3-1 amplitudes were reduced in response to both odors. Furthermore, the early potentials (N1, P2 and P3-1) of the chemosensory event-related potential (CSERP) appeared with longer latencies when subjects received negative feedback. The state effects of helplessness resemble the deviations in the CSERP found in depressed patients, suggesting a general mood effect.