Reward and Aversive Stimuli Produce Similar Nonphotic Phase Shifts

Sean W. Cain, Michael Verwey, Suzanne Hood, Povilas Leknickas, Ilia Karatsoreos, John S. Yeomans, Martin R. Ralph

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15 Citations (Scopus)


Circadian rhythms in rodents respond to arousing, nonphotic stimuli that contribute to daily patterns of entrainment. To examine whether the motivational significance of a stimulus is important for eliciting nonphotic circadian phase shifts in Syrian hamsters (Mesocricetus auratus), the authors compared responses to a highly rewarding stimulus (lateral hypothalamic brain stimulation reward [BSR]) and a highly aversive stimulus (footshock). Animals were housed on a 14:10-hr light-dark cycle until test day, when they were given a 1-hr BSR session (trained animals) or a 1-mA electric footshock at 1 of 8 circadian times, and were maintained in constant dark thereafter. Both BSR pulses and footshock produced nonphotic phase response curves. These results support the hypothesis that arousal resulting from the motivational significance of a stimulus is a major factor in nonphotic phase shifts.

Original languageEnglish
Pages (from-to)131-137
Number of pages7
JournalBehavioral Neuroscience
Issue number1
Publication statusPublished - Feb 2004
Externally publishedYes

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