<prompt> Lesion of which hypothalamic nuclei leads to loss of circadian rhythmDorsomedialVentromedialSupraopticSuprachiasmatic  <response>: The suprachiasmatic nucleus or nuclei, abbreted SCN, is a tiny region on the brain;s midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle, using around 20,000 neurons.Ref: Ganong;s review of medical physiology; 24th edition; page no:-278 