Extrastriate activity reflects the absence of local retinal input

Conscious Cogn. 2023 Aug 26;114:103566. doi: 10.1016/j.concog.2023.103566. Online ahead of print.ABSTRACTThe physiological blind spot corresponds to the optic disc where the retina contains no light-detecting photoreceptor cells. Our perception seemingly fills in this gap in input. Here we suggest that rather than an active process, such perceptual filling-in could instead be a consequence of the integration of visual inputs at higher stages of processing discounting the local absence of retinal input. Using functional brain imaging, we resolved the retinotopic representation of the physiological blind spot in early human visual cortex and measured responses while participants perceived filling-in. Responses in early visual areas simply reflected the absence of visual input. In contrast, higher extrastriate regions responded more to stimuli in the eye containing the blind spot than the fellow eye. However, this signature was independent of filling-in. We argue that these findings agree with philosophical accounts that posit that the concept of filling-in of absent retinal input is unnecessary.PMID:37639775 | DOI:10.1016/j.concog.2023.103566

Source: Consciousness and Cognition - August 28, 2023 Category: Neurology Authors: Poutasi W B Urale Lydia Zhu Roberta Gough Derek Arnold Dietrich Samuel Schwarzkopf Source Type: research