Related Experiment Video
Updated: May 1, 2026

Development of a Gaze-Contingent Display Framework Designed for Perceptual and Oculomotor Research with Simulated Central Vision Loss
Published on: April 11, 2025
Unlike in clinical blindsight patients, unconscious processing of chromatic information depends on early visual
Henry Railo1, Eki Andersson2, Valtteri Kaasinen3
1Department of Psychology, University of Turku, FI-20014 Turku, Finland; Centre for Cognitive Neuroscience, University of Turku, FI-20014 Turku, Finland.
Background:
Large amount of data concerning the neural mechanisms that mediate unconscious vision come from cortically blind patients who can process stimuli presented in their blind visual field. How well the findings generalize to neurologically healthy humans remains open.
Objective:
Using transcranial magnetic stimulation (TMS), we studied whether chromatic processing depends on the early visual cortex in healthy participants.
Method:
We employed a phenomenon called the redundant target effect (RTE): simple reaction times to two stimuli are faster than to one stimulus, even when one of the stimuli is presented outside consciousness.
Results:
The RTE produced by chromatically defined stimuli disappeared when the contralateral stimulus of two bilateral stimuli was suppressed from consciousness.
Conclusions:
In contrast to studies on blindsight patients, the results imply that the early visual cortex is necessary for the processing of chromatic information in neurologically healthy humans.
Related Concept Videos
Photoreceptors and Visual Pathways
Parallel Processing
Color Vision
Vision
Visual System
Once through the pupil, the light passes through the lens, a...
Anatomy of the Eyeball

