RESUMEN
OBJECTIVE: The hedonic value of odors is reflected in chemosensory evoked potentials with more salient unpleasant odors being processed differently from pleasant odors. However, it is not known if this effect is stable over time. It was examined if chemosensory evoked potentials towards pleasant and unpleasant odors change with repeated presentation. METHODS: 42 participants received two pleasant (Peach and PEA) and one unpleasant (H2S) intensity matched odors in a block design. Intensity and pleasantness were rated after each presentation. Subjective ratings, as well as N1 and P2 of the first stimulus of each block were compared with the two following stimuli of each block. RESULTS: Early and late components of the chemosensory evoked potentials had shorter latencies in response to the unpleasant H2S compared to PEA and Peach. Pleasantness ratings for H2S increased with repeated presentation but were far below neutral even for the third stimulus in a row. In line with this, for H2S only, the P2 amplitude diminished with repeated presentation. CONCLUSION: We assume that unpleasant stimuli catch more attention first hand. However, repeated presentation leads to reduced emotional salience of unpleasant stimuli only, which is mirrored in a decrease of neuronal activation.
Asunto(s)
Emociones/fisiología , Potenciales Evocados/fisiología , Habituación Psicofisiológica/fisiología , Odorantes , Olfato , Adulto , Análisis de Varianza , Electroencefalografía , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Estimulación Química , Adulto JovenRESUMEN
Developed in the 1990 s, the "Sniffin 'Sticks" test for the assessment of olfactory threshold, odor identification and discrimination has become a widely used tool both in clinical and research settings. Originally pencil-and-paper documented, it may now be applied using a computer program. The "Filemaker" based software "OLAF" guides the examiner through any user-defined arrangement of the test battery, stores all data in a database, and offers results sheets to be printed out for convenience. The royalty-free program may be downloaded from http://www.tu-dresden.de/medkhno/riechen_schmecken/olaf.zip as a runtime solution application. It is currently available in four languages (English, French, German, and Italian) which can be toggled by a single mouse click, and is suitable for Windows as well as Apple platforms. In conclusion, the currently described software is expected to further facilitate and standardize olfactory testing with the "Sniffin' Sticks" test battery.