Disruption of circadian clocks has ramifications for metabolism, brain, and behavior

Ilia N. Karatsoreos, Sarah Bhagat, Erik B. Bloss, John Morrison, Bruce S. McEwen

Research output: Contribution to journalArticle

280 Scopus citations

Abstract

Circadian (daily) rhythms are present in almost all plants and animals. In mammals, a brain clock located in the hypothalamic suprachiasmatic nucleus maintains synchrony between environmental light/dark cycles and physiology and behavior. Over the past 100 y, especially with the advent of electric lighting, modern society has resulted in a round-the-clock lifestyle, in which natural connections between rest/activity cycles and environmental light/dark cycles have been degraded or even broken. Instances in which rapid changes to sleep patterns are necessary, such as transmeridian air travel, demonstrate negative effects of acute circadian disruption on physiology and behavior. However, the ramifications of chronic disruption of the circadian clock for mental and physical health are not yet fully understood. By housing mice in 20-h light/dark cycles, incongruous with their endogenous ∼24-h circadian period, we were able to model the effects of chronic circadian disruption noninvasively. Housing in these conditions results in accelerated weight gain and obesity, as well as changes in metabolic hormones. In the brain, circadian-disrupted mice exhibit a loss of dendritic length and decreased complexity of neurons in the prelimbic prefrontal cortex, a brain region important in executive function and emotional control. Disrupted animals show decreases in cognitive flexibility and changes in emotionality consistent with the changes seen in neural architecture. Howour findings translate to humans living and working in chronic circadian disruption is unknown, but we believe that this model can provide a foundation to understand how environmental disruption of circadian rhythms impacts the brain, behavior, and physiology.

Original languageEnglish (US)
Pages (from-to)1657-1662
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number4
DOIs
StatePublished - Jan 25 2011
Externally publishedYes

Keywords

  • Biological clock
  • Cognitive function
  • Neuronal remodeling
  • Structural plasticity

ASJC Scopus subject areas

  • General

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