The superior colliculus refers to the rostral (front) bump on the lateral (side) part of the midbrain. It is, in fact, a pair of two colliculi, superior and inferior, on either side of the midbrain that together constitute the tectum.
The superior colliculus is a layered, multi-sensory structure. Its upper layer receives visual signals from the retina of the eye, while the lower layers process multiple signals from various other parts of the brain. This colliculus is not restricted to a visual role alone. It also helps with the orientation of the eyes and head.
Part of the colliculus sticks out in the direction of the spinal cord region. This key projection helps the head to respond to different sensory stimuli.
Movement of the eyes is also connected with the cells present in the lower layers of the colliculus. In mammals and other higher animals, the brain processes sensory inputs in correlation with the superior colliculus. In lower animals it helps to perceive any sudden movement that occurs before the retina.