Competing clocks: Metabolic status moderates signals from the master circadian pacemaker

Food anticipatory activity (FAA) may involve a food entrainable oscillator (FEO) that operates independently of the suprachiasmatic nucleus (SCN).

• The FEO responds to fasting and feeding cues to drive FAA outside typical arousal periods.
• Mechanisms that may allow FAA to occur include reducing SCN cell activation from retinal input.
• Transient disorganization of SCN outputs could facilitate behavioral manifestations of meal anticipation.
• There may be reduced sensitivity to SCN signals in hypothalamic areas that integrate homeostatic and circadian information.
• Understanding these mechanisms could inform interventions for managing the negative effects of irregular work schedules.

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