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Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder.

Publication ,  Journal Article
Morey, RA; Dunsmoor, JE; Haswell, CC; Brown, VM; Vora, A; Weiner, J; Stjepanovic, D; Wagner, HR; VA Mid-Atlantic MIRECC Workgroup; LaBar, KS
Published in: Transl Psychiatry
December 15, 2015

Fear conditioning is an established model for investigating posttraumatic stress disorder (PTSD). However, symptom triggers may vaguely resemble the initial traumatic event, differing on a variety of sensory and affective dimensions. We extended the fear-conditioning model to assess generalization of conditioned fear on fear processing neurocircuitry in PTSD. Military veterans (n=67) consisting of PTSD (n=32) and trauma-exposed comparison (n=35) groups underwent functional magnetic resonance imaging during fear conditioning to a low fear-expressing face while a neutral face was explicitly unreinforced. Stimuli that varied along a neutral-to-fearful continuum were presented before conditioning to assess baseline responses, and after conditioning to assess experience-dependent changes in neural activity. Compared with trauma-exposed controls, PTSD patients exhibited greater post-study memory distortion of the fear-conditioned stimulus toward the stimulus expressing the highest fear intensity. PTSD patients exhibited biased neural activation toward high-intensity stimuli in fusiform gyrus (P<0.02), insula (P<0.001), primary visual cortex (P<0.05), locus coeruleus (P<0.04), thalamus (P<0.01), and at the trend level in inferior frontal gyrus (P=0.07). All regions except fusiform were moderated by childhood trauma. Amygdala-calcarine (P=0.01) and amygdala-thalamus (P=0.06) functional connectivity selectively increased in PTSD patients for high-intensity stimuli after conditioning. In contrast, amygdala-ventromedial prefrontal cortex (P=0.04) connectivity selectively increased in trauma-exposed controls compared with PTSD patients for low-intensity stimuli after conditioning, representing safety learning. In summary, fear generalization in PTSD is biased toward stimuli with higher emotional intensity than the original conditioned-fear stimulus. Functional brain differences provide a putative neurobiological model for fear generalization whereby PTSD symptoms are triggered by threat cues that merely resemble the index trauma.

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Published In

Transl Psychiatry

DOI

EISSN

2158-3188

Publication Date

December 15, 2015

Volume

5

Issue

12

Start / End Page

e700

Location

United States

Related Subject Headings

  • Veterans
  • United States
  • Stress Disorders, Post-Traumatic
  • Male
  • Magnetic Resonance Imaging
  • Learning
  • Humans
  • Generalization, Psychological
  • Female
  • Fear
 

Citation

APA
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ICMJE
MLA
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Morey, R. A., Dunsmoor, J. E., Haswell, C. C., Brown, V. M., Vora, A., Weiner, J., … LaBar, K. S. (2015). Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder. Transl Psychiatry, 5(12), e700. https://doi.org/10.1038/tp.2015.196
Morey, R. A., J. E. Dunsmoor, C. C. Haswell, V. M. Brown, A. Vora, J. Weiner, D. Stjepanovic, H. R. Wagner, VA Mid-Atlantic MIRECC Workgroup, and K. S. LaBar. “Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder.Transl Psychiatry 5, no. 12 (December 15, 2015): e700. https://doi.org/10.1038/tp.2015.196.
Morey RA, Dunsmoor JE, Haswell CC, Brown VM, Vora A, Weiner J, et al. Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder. Transl Psychiatry. 2015 Dec 15;5(12):e700.
Morey, R. A., et al. “Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder.Transl Psychiatry, vol. 5, no. 12, Dec. 2015, p. e700. Pubmed, doi:10.1038/tp.2015.196.
Morey RA, Dunsmoor JE, Haswell CC, Brown VM, Vora A, Weiner J, Stjepanovic D, Wagner HR, VA Mid-Atlantic MIRECC Workgroup, LaBar KS. Fear learning circuitry is biased toward generalization of fear associations in posttraumatic stress disorder. Transl Psychiatry. 2015 Dec 15;5(12):e700.

Published In

Transl Psychiatry

DOI

EISSN

2158-3188

Publication Date

December 15, 2015

Volume

5

Issue

12

Start / End Page

e700

Location

United States

Related Subject Headings

  • Veterans
  • United States
  • Stress Disorders, Post-Traumatic
  • Male
  • Magnetic Resonance Imaging
  • Learning
  • Humans
  • Generalization, Psychological
  • Female
  • Fear