How light and food cues help keep the body’s internal clock in sync in mammals

Light stimuli induce phase shifting responses in clock genes, notably increasing Per1, Per2, and Dec1 expression.

• The suprachiasmatic nucleus (SCN) serves as the master circadian clock in mammals.
• Peripheral oscillators are synchronized by the SCN, particularly during ad libitum feeding.
• Temporal restricted feeding acts as a weak synchronizer for the SCN clockwork.
• Coupling restricted feeding with caloric restriction alters clock gene expression timing within the SCN.
• The circadian timing system components can be synchronized by conflicting temporal and metabolic cues.

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