Precollicular

Precollicular is an anatomical term used in neuroanatomy to describe structures that lie in front of the colliculi of the midbrain. The colliculi are two pairs of small rounded eminences on the dorsal surface of the midbrain—the superior colliculus involved in visual processing and the inferior colliculus in the auditory pathway. The precollicular designation is a relative one, applied to regions or tracts that are rostral or ventral to these tectal structures, depending on the perspective and orientation used in a given atlas. The term is encountered in descriptions of brainstem anatomy, comparative neuroanatomy, and historical surgical literature.

In practice, precollicular is used to delineate boundaries within the midbrain and adjacent regions when labeling nuclei, fiber tracts, lesions, or surgical corridors. For example, studies may refer to precollicular projections or precollicular nuclei to indicate their location in front of the colliculi. The term is often paired with its opposite, postcollicular, to specify locations behind the collicular structures.

Because the colliculi are central landmarks in the tectum, the precollicular region is important for anatomical mapping, neurophysiological experiments, and certain skull-base or brainstem surgical approaches that require a route anterior to the tectum. See also colliculus, tectum, midbrain, and brainstem anatomy.