Poster F129, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Altered feedback responses to negative gambling outcomes in combat PTSD
Matt Schalles1,2, Nikki Honzel3, Jary Larsen1, Felix Bacigalupo4, Carolyn Alderson1, Diane Swick1,4; 1VA Northern California Health Care System, 2Mills College, 3Carroll College, 4UC Davis
Cognitive deficits in Post-traumatic Stress Disorder can be subtle, such as impaired response inhibition (Swick et al. 2012) but relatively unperturbed error monitoring (Swick et al. 2015). We used EEG recordings to ask whether veterans with PTSD would exhibit neurocognitive deficits when engaged in a blackjack gambling task that combined aspects of response inhibition and error monitoring. Behaviorally we observed no differences between patients and matched military controls on task performance in terms of winnings or risk decision thresholds. Event-related potentials time-locked to win or loss feedback over frontal midline (Fz) showed within subject effects with the control group exhibiting a greater magnitude P3 for wins around 400ms, and both groups exhibiting a late (> 500 ms) positivity to wins (FCz). Patients exhibited greater frontal midline (FM) theta power (4-8 hz) around 250-300 ms for win conditions relative to loss, which is counter to predictions from previous work showing increased theta power for loss (Cohen et al, 2007) and negative outcomes (Cavanagh et. al., 2014). Patients also showed increases in low beta power (15-20 Hz) at later intervals (> 1000ms) in response to win conditions relative to loss. The relative lack of a feedback negativity ERP in patients, but presence of theta differences compared to controls, suggests that there may be a perturbed neural response to negative outcomes in this task. This perturbation may be specific to losses that are beyond the control of participants, as the effect was not observed for bust ("over 21") vs win.
Topic Area: THINKING: Decision making