Striatal responsiveness to reward under threat‐of‐shock and working memory load: A preliminary study

Abstract

Introduction Reward and stress are important determinants of motivated behaviors. Striatal regions play a crucial role in both motivation and hedonic processes. So far, little is known on how cognitive effort interacts with stress to modulate reward processes. This study examines how cognitive effort (load) interacts with an unpredictable acute stressor (threat‐of‐shock) to modulate motivational and hedonic processes in healthy adults. Materials and Methods A reward task, involving stress with unpredictable mild electric shocks, was conducted in 23 healthy adults aged 20–37 (mean age: 24.7 ± 0.9; 14 females) during functional magnetic resonance imaging (fMRI). Manipulation included the use of (a) monetary reward for reinforcement, (b) threat‐of‐shock as the stressor, and (c) a spatial working memory task with two levels of difficulty (low and high load) for cognitive load. Reward‐related activation was investigated in a priori three regions of interest, the nucleus accumbens (NAcc), caudate nucleus, and putamen. Results During anticipation, threat‐of‐shock or cognitive load did not affect striatal responsiveness to reward. Anticipated reward increased activation in the ventral and dorsal striatum. During feedback delivery, both threat‐of‐shock and cognitive effort modulated striatal activation. Higher working memory load blunted NAcc responsiveness to reward delivery, while stress strengthened caudate nucleus reactivity regardless reinforcement or load. Conclusions These findings provide initial evidence that both stress and cognitive load modulate striatal responsiveness during feedback delivery but not during anticipation in healthy adults. Of clinical importance, sustained stress exposure might go along with dysregulated arousal, increasing therefore the risk for the development of maladaptive incentive‐triggered motivation. This study brings new insight that might help to build a framework to understand common stress‐related disorders, given that these psychiatric disorders involve disturbances of the reward system, cognitive deficits, and abnormal stress reactivity.

Increased Reward-Related Activation in the Ventral Striatum During Stress Exposure Associated With Positive Affect in the Daily Life of Young Adults With a Family History of Depression. Preliminary Findings

“…Thirdly, our results did not evidence differences in stress ratings between the control and the stress conditions. This could be related to the small sample size as the results obtained in a larger associated sample could evidence significant stress ratings differences between the conditions ( 36 ). In addition, the different levels of cognitive load could have induced stress and be a confounding factor.…”

“…Sixteen asymptomatic first-degree relatives with family history of MDD (FHD; 12 females, mean age = 24.31 years, SD = 4.08), and sixteen age-, gender- and socioeconomic status (SES)-matched healthy controls (HC; 12 females, mean age = 25.19 years, SD = 4.79) with no parental history of mental disorder were recruited from the local community by advertisement at the University of Fribourg. The participants of the control group were selected from a larger sample [see ( 36 )] to match for age and gender the group of participants with increased family risk of depression. Participation was compensated in money and/or experimental hours for study plans.…”

“…The Fribourg Reward Task is a monetary incentive delayed task, that was previously shown to elicit striatal activation ( 36 ). Participants performed a spatial delayed recall task with two levels of cognitive load (low = 3 circles and high = 7 circles) differentiated by the number of circles to be remembered (see Figure 1 ).…”

“…A growing amount of evidence indicates that stress exposure and stress sensitivity are strongly associated with the onset of MDD (28)(29)(30)(31)(32). Stress experiences have been shown to affect striatal reward processing in the context of early-life stress, childhood emotional neglect (33,34), recent life stress (35), and experimental acute stress (36)(37)(38). In most cases, stress experiences reduced the activation of the striatum in response to reward.…”

Understanding And Restoring Dopaminergic Function In Fibromyalgia Patients Using A Mindfulness-Based Psychological Intervention: A [18F]-DOPA PET StudyStudy Protocol For The FIBRODOPA Study- A Randomized Controlled Trial

“…The total time in the scanner will be about 75 minutes. The subjects will perform the Fribourg reward task, an event related fMRI task adapted from the spatial delayed response task to measure neural responses to monetary reward (Gaillard et al 2019).…”