<prompt> Which of the following centers are involved in maintaining the circadian rhythm?Supraoptic nucleiPosterolateral nucleiVentrolateral nucleiSuprachiasmatic nuclei  <response>: The entrainment process in most cases is dependent on the suprachiasmatic nuclei SCN located bilaterally above the optic chiasma. Efferents from the SCN initiate neural and hormonal signals that enteain a wide variety of well known circadian rhythms including the sleep wake cycle and the secretion of the pineal hormone melatonin. 