Acute Stress Exposure and Expression of Instrumentally Conditioned Financial Preferences: An fMRI Study
Date of Award
Master of Science (MS)
Porcelli, Anthony J.
Neilson, Kristy A.
Recent research suggests acute stress exposure is associated with increased habit-based over goal-oriented decision making (e.g., Schwabe & Wolf, 2011). The current study examined whether acute stress promotes the expression of simple financial preferences “overtrained” to the point of habit in the face of a changing environment where said preferences were later rendered non-optimal. Over three days participants (N = 28) learned to discriminate between visual stimuli probabilistically associated with monetary gains or losses and made decisions between stimuli with real financial outcomes. On the fourth day after exposure to either an acute stressor or control procedure participants performed the same tasks during fMRI scanning, including a related task in which monetary values associated with the same stimuli were altered. Choice and fMRI data, psychophysiological measures and salivary cortisol were collected. Participants in both groups successfully made optimal decisions between stimuli on Days 1 to 3 (reaching asymptote on Day 2). During fMRI scanning after stimuli values were altered stressed participants made significantly more decisions consistent with original stimuli values, although these decisions were now financially detrimental, than did non-stressed participants. Thus, stressed participants made decisions more consistent with their overtrained (i.e., habit-based) preferences. In the control group, differential levels of BOLD activation, relative to stimulus valence, were observed in regions associated with goal-directed (i.e., caudate and prefrontal cortex) and habit-based (i.e., putamen) behaviors during both overtrained and novel stimulus-outcome pairings. In the acute stress group, similar differential BOLD activation was limited to the putamen and was only observed for overtrained pairings. During the decision-making portion of the task, increased BOLD activation was observed in the dorsal anterior cingulate cortex and insula for incorrect relative to correct responses in both groups. Further, alterations in dorsolateral prefrontal and entorhinal cortex suggest some stress-related impairment of executive control of memory. The current study adds to research that demonstrates a dual-process of decision-making and the propensity to resort to habitual behavior after exposure to acute stress. Further, these findings suggest stress-induced neural changes take place during both the learning and recall of reward-related information used in decision-making.