Development and organization of multimodal representation in cat superior colliculus.

The present paper examines developmental and organizational parallels between visual and nonvisual cells in the cat superior colliculus (SC). An attempt is made to relate these developmental and organizational features to the role the SC plays in orientation behavior. In young kittens visually guided behavior is virtually nonexistent and requires many weeks to develop. Similarly, kitten SC cells are unresponsive to visual stimuli until at least 7 days after birth, and it is only after many weeks that SC cells behave as do those of the adult. In contrast to the development of visual cells, however, some neurons responsive to somatic stimuli are present in the SC on the day of birth, and cells responsive to acoustic stimuli appear several days later. Thus, the sequence in which modality represenstation appears in the cat SC parallels the developmental chronology of the use of different sensory cues for orientation. These data indicate that the functional roles of the visual, somatic, and acoustic representations may be similar. The finding that the organization of the somatic representation in the SC is similar to, and in register with, the visual representation is consistent with this possibility. It is suggested that the SC can utilize cues from a variety of modalities in order to facilitate appropriate orientation behavior.