Early-Stage Neural Processing Reveals Distinctive Responses to Saliency-Differentiated Colors in Various Types of Color Vision

Abstract

AbstractPeople with protan or deutan color vision are expected to have reduced chromatic sensitivity on the red-green color axis due to altered cone sensitivities; however, complemented sensitivities have been reported in some studies. The mechanism involved in the enhanced sensitivity is considered to encompass a broad spectrum of psychophysiological processes. Nonetheless, the specific details remain unknown. This study investigated the differences in attention-related neural activities between common trichromats and deuteranomalous trichromats during the observation of chromatically identical colors that differ in saliency. Global field power and event-related potentials were analyzed to elucidate how higher cognitive process, particularly attention, manifests in the temporal domain of neural processes in response to stimuli saliency, across color vision types. The finding revealed increased neural activity toward less salient color stimuli in both color vision groups, reflecting a heightened attentional level. Notably, distinct activity patterns were observed at different time frames: common trichromats exhibited at later positive component (P3), and deuteranomalous trichromats exhibited at earlier positive component (P2). Surprisingly, despite their diminished chromatic sensitivity, deuteranomalous trichromats responded quicker to the saliency differences. The result suggests that temporal characteristics play a crucial role in complementary mechanisms in chromatic sensitivities in individuals with diverse color vision.