Biol Psychiatry 2012; 71:78S-79S. [Paper presented at the at the 67th Annual Meeting of the Society of Biological Psychiatry (SOBP) in Philadelphia, PA, May 3 - 5, 2012.]
Effects of odor valence and arousal on event-related potentials (ERPs) in healthy adults and depressed patients
Jürgen Kayser1,2, Craig E. Tenke1,2, Christopher J. Kroppmann1, Daniel M. Alschuler1, Shiva Fekri1, Jonathan W. Stewart2,3, Patrick J. McGrath2,3, Bruce I. Turetsky4, Gerard E. Bruder1,2
1 Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY
2 Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, NY
3 Depression Evaluation Service, New York State Psychiatric Institute, New York, NY
4 Department of Psychiatry, University of Pennsylvania, Philadelphia, PA
Abstract Background: Despite the overlap of cortical and limbic structures involved in olfaction, emotion and depression, there has been little study of olfactory function in depression. Methods: 49-channel ERPs were recorded from 25 clinically-depressed and 27 healthy controls during an odor detection task using pleasant (Citronalva; CIT) and unpleasant (hydrogen sulfide; H2S) stimuli. High or low odor concentrations or blank air were presented unilaterally by a constant-flow olfactometer (ISI 15-21 s). Subjects indicated odor presence via foot pedal. Neuronal generator patterns underlying ERPs were identified and measured by unrestricted Varimax-PCA of reference-free current source densities (CSD). Results: Replicating previous findings for H2S stimuli (Kayser et al., 2010), CSD waveforms were characterized across odors by an early N1 sink (320 ms, bilateral centrotemporal) and a late P2 source (735 ms, mid-centroparietal). Whereas N1 sink varied with odor intensity, P2 source varied with odor valence (H2S > CIT). CSD amplitude and topography were highly correlated with individual ratings of valence (P2) in both groups but arousal (N1) in controls only. However, CSD waveforms and topographies did not differ between groups. Likewise, depressed patients showed normal odor identification and thresholds (Sniffin' Sticks), and did not differ from controls in detection accuracy for all conditions (74-91% correct). Conclusions: Although ERP/CSD measures directly reflected valence and arousal properties of pleasant and unpleasant odors, there was no evidence of impaired olfactory/emotional processing in depression. However, the dissociation of N1 amplitude and arousal ratings in patients may suggest abnormal odor perception on an "early sensory" level in depression. References Kayser J, Tenke CE, Malaspina D, Kroppmann CJ, Schaller JD, Deptula A, et al (2010). Neuronal generator patterns of olfactory event-related brain potentials in schizophrenia. Psychophysiology 47(6):1075-1086. Key Words: depression; olfaction; ERP; valence; arousal [Supported by NIMH grant MH082393]. |