The<unk> , or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system. Through reciprocal bilateral projections from the retina, it is involved primarily in mediating behavioral responses to acute changes in ambient light such as the pupillary light reflex, the optokinetic reflex, and temporary changes to the circadian rhythm. In addition to the pretectum's role in the visual system, the anterior<unk>  nucleus has been found to mediate somatosensory and nociceptive information.
Pretectal area
Watershed area 
Fusiform body area
Postcentral sulcus
Suboccipital triangle
Collateral eminence
Periaqueductal gray
Occipital triangle