Are Daily Biological Clocks Found Throughout the Mammal Brain, Not Just in the Main Body Clock?

Evidence suggests that multiple brain regions, including the olfactory bulb and amygdala, exhibit circadian rhythms in clock gene expression and activity.

• The suprachiasmatic nucleus (SCN) has traditionally been viewed as the sole circadian pacemaker in mammals.
• Recent findings indicate that other brain areas also display clock-like activities.
• Regions such as the olfactory bulb, amygdala, and various hypothalamic nuclei show circadian rhythms in hormone output and electrical activity.
• These findings challenge the uniclock model of circadian regulation.
• The presence of additional neural pacemakers may alter our understanding of circadian systems at the organism level.

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