Reminiscing about positive memories buffers acute stress responses

Abstract

Recalling happy memories elicits positive feelings and enhances one's wellbeing, suggesting a potential adaptive function in using this strategy for coping with stress. In two studies, we explored whether recalling autobiographical memories that have a positive content - i.e., remembering the good times - can dampen the hypothalamic-pituitary-adrenal (HPA) axis stress response. Participants underwent an acute stressor or control task followed by autobiographical memory recollection (of only positive or neutral valence). Across both studies, recalling positive, but not neutral, memories resulted in a dampened cortisol rise and reduced negative affect. Further, individuals with greater self-reported resiliency showed enhanced mood, despite stress exposure. During positive reminiscence, we observed engagement of corticostriatal circuits previously implicated in reward-processing and emotion regulation, and stronger connectivity between ventrolateral and dorsolateral prefrontal cortex as a function of positivity. These findings highlight the restorative and protective function of self-generated positive emotions via memory recall in the face of stress.

Keywords: Autobiographical Memory; Cortisol; Positive Emotion; Prefrontal Cortex; Stress; Striatum; Wellbeing.

Figures

Figure 1. Schematic of Experimental Procedure and Timeline of Neuroendocrine Assessments for Day 2 (Stress Manipulation or Control Task)

Salivary samples were collected immediately before the stress or control procedure (s1, baseline), after memory recollection when cortisol was expected to peak (s2, peak, +20 min), and at the conclusion of the experiment when cortisol was expected to recover (s3, recovery, +50 min).

Figure 2. Neuroendocrine Responses to Acute Stress in the Behavioral Study

a) Baseline-corrected salivary cortisol measured in micrograms per deciliter at three time points across the experiment including immediately before the SECPT/control procedure (baseline), as well as 20 min (peak) and 50 min (recovery) after the SECPT/control procedure for all participants (N = 134). b) Cortisol response in terms of area under the curve with respect to increases from baseline (AUCI). The Stress-Neutral group has a significantly larger AUCI cortisol response than the other three groups. *p < .05; error bars denote SEM.

Figure 3. Resiliency Mediates the Relationship between Emotion Ratings during Memory Recall and Subsequent Mood for Individuals in the Stress-Positive Group

a) Greater resiliency (measured by the CD-RISC scale; N = 33) is associated with greater positive feelings during positive memory recollection. b) Greater resiliency is also associated with enhanced mood after positive memory recollection. c) Mediational model between emotion during recall, self-reported resiliency, and mood after recall. Path a: effect of emotion during recall on resiliency; path b: effect of resiliency on mood after recall, controlling for emotion during recall; path c: total effect of emotion during recall on mood after recall; and path c’: direct effect of emotion during recall on mood after recall, controlling for resilience. Path values represent unstandardized regression coefficients. *p

Figure 4. Neuroendocrine Responses to Acute Stress in the fMRI Study

a) Baseline-corrected salivary cortisol measured in micrograms per deciliter at four time points across the experiment including immediately before the SECPT/control procedure (baseline), as well as 2 min, 24 min (peak) and 58 min (recovery) after the SECPT/control procedure for all participants (N = 43). b) Cortisol response in terms of area under the curve with respect to increases from baseline (AUCI). Stress-Neutral group has a significantly larger AUCI cortisol response than the Stress-Positive group. *p < .05; error bars denote SEM.

Figure 5. Neural Activity during the Recall of Autobiographical Memory under Acute Stress

a) A parametric modulation of positive emotion ratings during memory recall in Stress-Positive individuals (N = 22) revealed activity in regions previously implicated in emotion regulation, such as the VLPFC, and in reward-processing, such as the MPFC and ventral striatum. p