Superior colliculus
From Freepedia
The superior colliculus (Latin: hill) is part of the brain that sits below the thalamus and surrounds the pineal gland in the mesencephalon of vertebrate brains. This structure comprises the rostral aspect of the midbrain, anterior to the periaqueductal gray and adjacent the inferior colliculus. The inferior and superior colliculi are known collectively as the corpora quadrigeminna, or four twins.
In humans the superior colliculus is involved in the generation of saccadic eye movements and hand-eye coordination. Afferents to the superior collicus originate in the cerebral cortex, inferior colliculus, retina, basal ganglia, and spinal cord. In humans, as in most larger vertebrates, sensory information that goes to the mesencephalon will be relayed via the thalamus to the cerebral cortex for interpretation. However, the superior colliculus can also mediate some oculomotor movements without cortical involvement.
The superior colliculus receives visual, as well as auditory, inputs in its superficial layers, and the deeper layers of the colliculus are connected to many sensorimotor areas of the brain. The colliculus as a whole is thought to help orient the head and eyes toward something seen or heard.
The comparable area of the mesencephalon of non-mammalian vertebrates is called the optic tectum. In amphibians, reptiles and fish, the optic tectum is the main visual processing area. In contrast, the role of the superior collicus for visual discrimination is less prominent in more complex vertebrates.
