Disparity and motion-in-depth processing in human visual cortex
Seminar | January 27 | 11:10 a.m.-12:30 p.m. | 489 Minor Hall
Anthony Norcia, Stanford University
The lateral separation of the two eyes creates slight retinal image differences that provide binocular disparity and binocular motion cues that can be used to extract information about depth in the world. To gain insight about the neural mechanisms involved in processing these cues, we use cue-isolating stimulation techniques to study the dynamics of brain responses to changing disparity cues, binocular motion cues and their combination via high-density EEG recordings in adults and in developing infants and children. We use adult fMRI activations to study their spatial localization. We find that both disparity and motion-based depth cues are strikingly immature in 4-7 month-old infants. In the case of the disparity system, the immaturity arises in the lack of sensitivity to relative disparities that are primarily processed in extra-striate visual areas. In the case of motion cues, the immaturity lies in the lack of suppressive binocular interactions typical of the adult and a separate lack of sensitivity to references. Taken together, our results suggest a hierarchy of cue-sensitivity and processing strategy for binocular disparity and binocular motion cues.