How Does the Suprachiasmatic Nucleus (SCN) Control Circadian Rhythm?
The SCN is located in the anterior region of the hypothalamus, and contains roughly 20,000 neurons. The SCN can be divided into two main sections depending on the neuropeptide expression.
The ‘Core’ of the SCN is mainly comprised of vasoactive intestinal peptide (VIP) expressing cells. The core mainly receives input from the retina and other brain regions.
On the other hand, the ‘Shell’ in mainly comprised of arginine vasopressin (AVP) expressing cells. The shell receives inputs mainly from the cortex, basal forebrain, and hypothalamus. The SCN sends outputs to various parts of the brain such as the medial areas of the hypothalamus and thalamus.
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