Timing could change fear responses
Andreatta, M., Mühlberger, A., Gerdes, A. B. M., Wieser, M. J., Gerber, B., and Pauli, P.
University of Wuerzburg
An animal study found that aversive events have appetitive properties depending on timing. In fact, when a conditioned stimulus (CS+) followed a painful unconditioned stimulus (US), fruitflies preferred CS+ more than a control stimulus. We investigated whether such appetitive effect in flies shares a common neuronal circuitry with rewarding processing in humans. We used event-related functional magnetic resonance imaging (fMRI) in a differential conditioning paradigm. Participants undergone either forward (CS+ preceded US) or backward (CS+ followed US) conditioning. Participants reported CS+ after both kinds of conditioning as being emotionally "negative". However, the analysis of neuronal activation revealed that the cingulate cortex and the supplementary motor cortex (SMA) were activated by CS+ alone comparing forward and backward conditioning. We concluded that forward but not backward conditioning has aversive properties because of regions which mediate expression and preparation of fear responses respectively.