Neurobiological Effects of Context on Emotion Regulation

Abstract

The ability to regulate emotions is a critical feature of healthy psychological functioning. It is therefore essential to understand under what conditions different emotion regulation strategies may or may not be effective. Neurobiological evidence suggests that certain contexts, including acute psychological stress and sleep deprivation, may impair emotion regulation ability. However, there is little data on the causal effects of these contexts on emotion regulation processing. In this dissertation, I present three studies that examine the neurobiological effects of stress and sleep deprivation on two emotion regulation strategies: cognitive reappraisal and affect labeling. In Paper 1, we induced acute psychosocial stress and measured its impact (relative to a control manipulation) on emotional responding during a cognitive reappraisal task while participants underwent fMRI. Findings revealed no evidence that stress modulated the effects of cognitive reappraisal on subjective or physiological measures of emotional responding. Modest effects of stress on reappraisal-related neural activation were observed in the prefrontal cortex and amygdala, but these relationships were statistically fragile. These findings were extended in Paper 2, in which we tested the effects of one night of total sleep deprivation on the same cognitive reappraisal task. Once again, results showed no evidence that the context manipulation (this time sleep deprivation) affected subjective, physiological, or neural responses to cognitive reappraisal. However, it was not the case that these null effects generalized to all types of emotion regulation. In Paper 3, we examined the effects of sleep deprivation on affect labeling, an implicit emotion regulation strategy hypothesized to rely on the cognitive control functions of the right ventrolateral prefrontal cortex. Findings revealed up-regulated recruitment of this prefrontal region as well as increased functional connectivity with the amygdala during sleep deprivation. Increased coupling was associated with lower baseline negative affect when sleep deprived, suggesting that sleep-loss-induced increases in activation may have adaptive buffering effects on mood. Together, findings from these papers show that two context manipulations expected to impair emotion regulation ability do not appear to impact cognitive reappraisal, despite influencing the processing of a more implicit emotion regulation strategy. This work calls for a careful examination of the way emotion regulation is presently studied and whether cognitive reappraisal, or only certain aspects of it, may in fact be robust to the effects of contextual factors like stress and sleep deprivation.