Elucidating behavioral and functional connectivity markers of aberrant threat discrimination in PTSD

John R. Keefe, Benjamin Suarez-Jimenez, Xi Zhu, Amit Lazarov, Ariel Durosky, Sara Such, Caroline Marohasy, Shmuel Lissek, Yuval Neria*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background: Patients with posttraumatic stress disorder (PTSD) tend to overgeneralize threat to safe stimuli, potentially reflecting aberrant stimuli discrimination. Yet, it is not clear whether threat overgeneralization reflects general discrimination deficits, or rather a specific bias related to aversive stimuli. Here we tested this question and characterized the neural correlates of threat discrimination. Methods: One-hundred and eight participants (33 PTSD; 43 trauma-exposed controls; 32 healthy controls) completed an emotionally neutral complex shape discrimination task involving identifying in 42 similar pairs the previously observed shape; and an emotionally aversive discrimination task, involving providing risk ratings for an aversive conditioned stimulus (CS+), and for several stimuli gradually differing in size from the original CS+. Resting state functional connectivity (rsFC) was collected before completing the tasks. Results: No group differences emerged on the emotionally neutral task. Conversely, on the emotionally aversive task, individuals with PTSD had steeper linear risk rating slopes as the stimuli more resembled the conditioned stimulus. Finally, lower rsFC of amygdala-default mode network (DMN) and DMN-salience network (SN) were associated with steeper risk slopes, while for hippocampus-SN, lower rsFC was found only among participants with PTSD. Conclusions: Individuals with PTSD show deficits in discrimination only when presented with aversive stimuli. Dysregulated discrimination pattern may relate to a lack of input from regulatory brain areas (e.g., DMN/hippocampus) to threat-related brain areas (e.g., SN/amygdala).

Original languageEnglish
Pages (from-to)891-901
Number of pages11
JournalDepression and Anxiety
Issue number12
StatePublished - Dec 2022


  • PTSD
  • fMRI
  • learning
  • stimuli discrimination
  • threat


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