Medicine & USMLE

Suprachiasmatic Nucleus

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Hypothalamic Nuclei
  1. Suprachiasmatic Nucleus
  2. Paraventricular and Supraoptic Nuclei
  3. Lateral Nucleus
  4. Ventromedial Nucleus
  5. Anterior Nucleus
  6. Posterior Nucleus
  7. Preoptic Nuclei

Suprachiasmatic Nucleus

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Summary

The suprachiasmatic nucleus is a nucleus that resides in the hypothalamus of the brain. This nucleus works to regulate our circadian or sleep rhythm, by taking in light information from the retina and regulating other parts of the brain like the pineal gland and medulla to affect sleep.

Key Points

  • Suprachiasmatic Nucleus
    • Location
      • Hypothalamus
    • Functions
      • Regulates circadian rhythm (sleep)
        • Receives visual information from retina → this helps to regulate sleep cycles by using light/luminance information
        • Relays light information to other hypothalamic nuclei + pineal gland (mediating melatonin)
        • Responds to melatonin and melatonin receptor agonists (e.g. Ramelteon), which is thought to result from feedback regulation of pineal gland
    • Lesions
      • Lesions lead to sleep and circadian rhythm disruptions