Stress-Induced Mesolimbic Reward Activation in Healthy Individuals with a History of Stressful Life Events

Julia Hall, BA

Brigham and Women’s Hospital
Stress-Induced Mesolimbic Reward Activation in Healthy Individuals with a History of Stressful Life Events

Scientific Abstract

Background: Stressful life events (SLE) can lead to dysfunction of neural reward circuitry and dysregulation of the HPA-axis, contributing to psychiatric disorders (e.g., depression, PTSD). Many people who experience SLE, however, do not develop psychiatric disorders and are thought to be resilient. Past studies have found that robust reward circuitry and HPA regulation contribute to adaptive functioning after SLE, but activity in these circuits following induction of acute stress has not been investigated. We examined HPA-axis reactivity and mesolimbic circuitry activation during reward processing after an acute stressor in healthy individuals with and without history of SLE.

Method: Thirty-nine healthy subjects with past SLE (SLE+; 11F/11M) and without past SLE (SLE–; 8F/9M) completed two study visits: one including a stress version and the other including a no-stress version of the Maastricht Acute Stress Test (MAST). SLE was assessed with the Brief Trauma Questionnaire (BTQ). Both visits involved serial measurements of cortisol, mood ratings, and an fMRI scan session including a monetary incentive delay task. Data were analyzed using SPSS and SPM12.

Results: Cortisol and subjective ratings of anxiety pre- and post-MAST did not differ between SLE+ and SLE– groups at stress or no-stress visits. During the stress visit, the SLE+ group exhibited greater activation in the nucleus accumbens (NAcc, pFWE=0.028) during anticipation of monetary reward, relative to SLE–. Hyperactivation in the NAcc in the SLE+ group remained significant after removing subjects whose SLE occurred after age 18 (pFWE=0.035). During receipt of monetary reward, hyperactivation in the amygdala was observed in the SLE+ group, compared to SLE–, at the trend level (pFWE=0.06). There were no differences in brain activation between SLE– and SLE+ during the no-stress visit.

Conclusion: These results suggest that acute psychosocial stress was associated with hyperactivation of reward circuitry in SLE+ individuals, but not SLE–, after acute stress. These findings contribute to the understanding of mechanisms underlying response to trauma in individuals with a history of SLE.

SoundCloud Transcript

Hello. My name is Julia Hall. I am a research assistant in Dr. Laura Holston’s research lab at Brigham and Women’s Hospital. And I’m grateful for the opportunity to present my research on stress induced mesolimbic reward activation in healthy individuals with a history of stressful life events.

Julia Hall:

Background: stress life events can lead to dysfunction of neural reward circuitry and dysregulation of the HPA axis. And this contributes to psychiatric disorders such as depression and PTSD. The majority of individuals however, adapt to extreme stress, exhibiting resilience. Studies investigating the reward circuitry in HPA axis reactivity of healthy individuals with past trauma and those without have found similar HPA functioning, but contradicting patterns of mesolimbic activation in response to rewarding stimuli. Though resilience tends to be associated with robust neural reward activity in HPA axis functioning, no studies have explored the direct impact of acute stress on these circuits between healthy people with past trauma and those without. The objective of the study was to compare HPA axis functioning and mesolimbic brain activity during reward processing in mentally healthy individuals with and without past trauma.

Julia Hall:

Methods: subjects were 39 individuals and they were divided into two groups based on their responsiveness to a modified version of the brief trauma questionnaire. The two groups are SLE stands for stressful life events minus so healthy people without stressful life events and SLE plus who do have history of stressful life events.

Julia Hall:

Subjects attended two visits scheduled one week apart, one including the stress version and one, including the no stress version of the Maastricht acute stress test (“MAST”). Both visits involved breakfast, measurements of cortisol, mood ratings in an FMRI scanning session, including a monetary incentive delay task. Questionnaires included the threat challenge questionnaire also known as the TCQ in visual analog scale mood ratings.

Julia Hall:

Results: results of the TCQ showed that participants felt more threatened by the Mast after the stress visit compared to the no stress visit. But there were no group differences between SLE plus and SLE minus. As for a visual analog scale ratings. Participants endorsed significantly increased tension after the Mast at the stress visit compared to the no stress visit. But there again were no differences in tension after the Mast between SLE plus and SLE minus.

Julia Hall:

Regarding changes in cortisol, present changing cortisol pre and post Mast was greater at the stress visit compared to the no stress visit. But again, no differences between groups. As for brain data, during the stress visit left nucleus accumbens activation during reward anticipation was stronger in SLE plus versus SLE minus the significance in the left nucleus accumbens remained after removing individuals whose stressful life event occurred after the age of 18.

Julia Hall:

Discussion: our results suggest that acute psychosocial stress is associated with hyperactivation of reward circuitry during anticipation of monetary gains in healthy individuals have past trauma relative to healthy individuals with no past trauma, despite similar HPA axis responses and subjective ratings of mood. These findings align with prior studies have found resilience, which is the ability to cope with and overcome extreme stress to be associated with increased activation in the ventral striatum after recent stressful events.

Julia Hall:

However, other studies have found no such relationship between recent stressful events and ventral striatum activity. Additional research is needed to elucidate whether ventral striatum responsiveness to reward after stressful life events, predicts the ability to effectively cope with novel psychosocial stressors. Understanding the mechanisms that contribute to resilience after trauma may shed light on targets for intervention to mitigate PTSD and depression symptomology as a result of stressful life events.

 

Live Zoom Session – April 21st

research Areas

Authors

Julia Hall, Hyeonmin Ahn, PhD, Benjamin Ryder, Jill M. Goldstein, PhD, Daniel G. Dillon, PhD, Diego A. Pizzagalli, PhD, Janet Rich-Edwards, PhD, and Laura M. Holsen, PhD

Principal Investigator

Laura Holsen, PhD

Affiliated Website