Nature's Clocks and Human Mood: The Circadian System Modulates Reward Motivation

作者：Murray Greg^*; Carrington Melinda J; Nicholas Christian L; Kleiman Jan; Dwyer Robyn; Allen Nicholas B; Trinder John

来源：Emotion, 2009, 9(5): 705-716.

DOI：10.1037/a0017080

• positive affect
• light/dark cycle
• adaptation

Existing literature on reward motivation pays scant attention to the fact that reward potential of the environment varies dramatically with the light/dark cycle. Evolution, by contrast, treats this fact very seriously: In all species, the circadian system is adapted to optimize the daily rhythm of environmental engagement. We used 3 standard protocols to demonstrate that human reward motivation, as measured in the dynamics of positive affect (PA), is modulated endogenously by the circadian clock. Under naturalistic conditions, 13.0% of PA variance was explained by a 24-hr sinusoid. In a constant routine protocol, 25.0% of PA variance was explained by the unmasked circadian rhythm in core body temperature (CBT). A forced desynchrony study showed PA to align with CBT in exhibiting circadian periodicity independent of a 28-hr sleep/wake cycle. It is concluded that the circadian system modulates reward activation, and implications for models of normal and abnormal mood are discussed.

• 出版日期2009-10