Frontiers in Behavioral Neuroscience (Feb 2014)

Medial prefrontal cortex stimulation modulates the processing of conditioned fear

  • Anne eGuhn,
  • Thomas eDresler,
  • Marta eAndreatta,
  • Laura D. Müller,
  • Tim eHahn,
  • Sara V. Tupak,
  • Sara V. Tupak,
  • Thomas ePolak,
  • Jürgen eDeckert,
  • Martin J. Herrmann

DOI
https://doi.org/10.3389/fnbeh.2014.00044
Journal volume & issue
Vol. 8

Abstract

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The extinction of conditioned fear is dependent on an efficient interplay between the amygdala and the medial prefrontal cortex (mPFC). In rats, high-frequency electrical mPFC stimulation was shown to improve extinction by a reduction of amygdala activity. However, so far it is unclear whether stimulation of homologues regions in humans might have similar beneficial effects.Healthy volunteers received one-session of either active or sham repetitive transcranial magnetic stimulation (rTMS) covering the mPFC while undergoing a two-day fear conditioning and extinction paradigm. rTMS was applied offline after fear acquisition in which one of two faces (CS+ but not CS-) was associated with an aversive scream (UCS). Immediate extinction learning (day 1) and extinction recall (day 2) were conducted without UCS delivery. Conditioned responses were assessed in a multimodal approach using fear-potentiated startle (FPS), skin conductance responses (SCR), functional near-infrared spectroscopy (fNIRS) and self-report scales. Consistent with the hypothesis of a modulated processing of conditioned fear after high-frequency rTMS, the active group showed a reduced CS+/CS- discrimination during extinction learning as evident in FPS as well as in SCR and arousal ratings. FPS responses to CS+ further showed a linear decrement throughout both extinction sessions. This study describes the first experimental approach of influencing conditioned fear by using rTMS which can be a basis for future studies investigating a complementation of mPFC stimulation to cognitive behavioral therapy.

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