The human emotional brain without sleep - a prefrontal amygdala disconnect

Abstract

Sleep deprivation is known to impair a range of functions, including immune regulation and metabolic control, as well as neurocognitive processes, such as learning and memory [1]. But evidence for the role of sleep in regulating our emotional brain-state is surprisingly scarce, and while the dysregulation of affective stability following sleep loss has received subjective documentation [2,3], any neural examination remains absent. Clinical evidence suggests that sleep and emotion interact; nearly all psychiatric and neurological disorders expressing sleep disruption display corresponding symptoms of affective imbalance [4]. Independent of sleep, knowledge of the basic neural and cognitive mechanisms regulating emotion is remarkably advanced. The amygdala has a well-documented role in the processing of emotionally salient information, particularly aversive stimuli [5,6]. The extent of amygdala engagement can also be influenced by a variety of connected systems, particularly the medial-prefrontal cortex (MPFC); the MPFC is proposed to exert an inhibitory, top-down control of amygdala function, resulting in contextually appropriate emotional responses [5,6]. We have focused on this network and using functional magnetic resonance image (fMRI) have obtained evidence, reported here, that a lack of sleep inappropriately modulates the human emotional brain response to negative aversive stimuli (see Supplemental data available on-line with this issue). © 2007 Elsevier Ltd. All rights reserved.