Retinohypothalamic tract:

Watch this 2-Minute Neuroscience video to learn more about the suprachiasmatic nuclei and the role of the retinohypothalamic tract in coordinating circadian rhythms.

pathway that travels from the retina to the suprachiasmatic nuclei of the hypothalamus. The retinohypothalamic tract sends information to the suprachiasmatic nuclei regarding the amount of light in the external environment; the suprachiasmatic nuclei use this information to coordinate circadian rhythms with the solar day.