TY - JOUR
T1 - Pavlovian aversive and appetitive odor conditioning in humans
T2 - Subjective, peripheral, and electrocortical changes
AU - Hermann, Christiane
AU - Ziegler, Silvio
AU - Birbaumer, Niels
AU - Flor, Herta
PY - 2000
Y1 - 2000
N2 - Differential Pavlovian conditioning of aversive and appetitive odors was examined in 30 male healthy subjects. The appetitive conditioning group (n = 15) received a pleasant odor (vanilla), the aversive conditioning group (n = 15) an unpleasant odor (fermented yeast) as unconditioned stimulus. Slides of two different neutral faces that were easy to discriminate served as conditioned stimuli (CS). An EEG was recorded from nine electrodes. Electromyographic activity was measured bilaterally from the m. corrugator supercilii and m. zygomaticus. The startle response was obtained from the m. orbicularis oculi. Finally, heart rate and skin conductance response were assessed. The subjective data and the skin conductance response revealed successful differential aversive conditioning. By contrast, the pleasant odor failed to produce appetitive odor conditioning. The conditioned and unconditioned response of the corrugator muscles confirm previous reports on the m. corrugator being strongly involved in the expression of negative affect. Contrary to previous findings, magnitude of the startle reflex was not found to be modulated depending on the valence of the CS. Central psychophysiological parameters showed little change during differential conditioning. The presence of subjective-evaluative conditioning and contingency awareness without significant changes in cortical and cardiovascular correlates might be due to extremely localized cortical processing of conditioned olfactory cues or primarily subcortical processing. The latter interpretation is strengthened by the presence of differential conditioning in non-voluntary responses such as the corrugator muscles.
AB - Differential Pavlovian conditioning of aversive and appetitive odors was examined in 30 male healthy subjects. The appetitive conditioning group (n = 15) received a pleasant odor (vanilla), the aversive conditioning group (n = 15) an unpleasant odor (fermented yeast) as unconditioned stimulus. Slides of two different neutral faces that were easy to discriminate served as conditioned stimuli (CS). An EEG was recorded from nine electrodes. Electromyographic activity was measured bilaterally from the m. corrugator supercilii and m. zygomaticus. The startle response was obtained from the m. orbicularis oculi. Finally, heart rate and skin conductance response were assessed. The subjective data and the skin conductance response revealed successful differential aversive conditioning. By contrast, the pleasant odor failed to produce appetitive odor conditioning. The conditioned and unconditioned response of the corrugator muscles confirm previous reports on the m. corrugator being strongly involved in the expression of negative affect. Contrary to previous findings, magnitude of the startle reflex was not found to be modulated depending on the valence of the CS. Central psychophysiological parameters showed little change during differential conditioning. The presence of subjective-evaluative conditioning and contingency awareness without significant changes in cortical and cardiovascular correlates might be due to extremely localized cortical processing of conditioned olfactory cues or primarily subcortical processing. The latter interpretation is strengthened by the presence of differential conditioning in non-voluntary responses such as the corrugator muscles.
KW - Appetitive learning
KW - Aversive learning
KW - Human
KW - Odor conditioning
KW - Psychophysiological correlates
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U2 - 10.1007/s002210000343
DO - 10.1007/s002210000343
M3 - Article
C2 - 10853945
AN - SCOPUS:0034020034
VL - 132
SP - 203
EP - 215
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 2
ER -