The neural basis of multisensory integration in the midbrain: its organization and maturation.

Multisensory integration describes a process by which information from different sensory systems is combined to influence perception, decisions, and overt behavior. Despite a widespread appreciation of its utility in the adult, its developmental antecedents have received relatively little attention. Here we review what is known about the development of multisensory integration, with a focus on the circuitry and experiential antecedents of its development in the model system of the multisensory (i.e., deep) layers of the superior colliculus. Of particular interest here are two sets of experimental observations: (1) cortical influences appear essential for multisensory integration in the SC, and (2) postnatal experience guides its maturation. The current belief is that the experience normally gained during early life is instantiated in the cortico-SC projection, and that this is the primary route by which ecological pressures adapt SC multisensory integration to the particular environment in which it will be used.