Frequency-specific and periodic masking of peripheral characters by delayed foveal input

The foveal-feedback mechanism supports peripheral object recognition by processing informationabout peripheral objects in foveal retinotopic visual cortex. When a foveal object is asynchronouslypresented with a peripheral target, peripheral discrimination performance is affected differentlydepending on the relationship between the foveal and peripheral objects. However, it is not clearwhether the delayed foveal input competes for foveal resources with the information processedby foveal-feedback or masks it. In the current study, we tested these hypotheses by measuring theeffect of foveal noise at different spatial frequencies on peripheral discrimination of familiar and novelcharacters. Our results showed that the impairment of foveal-feedback was strongest for low-spatialfrequency noise. A control experiment revealed that for spatially overlapping noise, low-spatialfrequencies were more effective than medium-spatial frequencies in the periphery, but vice versa inthe fovea. This suggests that the delayed foveal input selectively masks foveal-feedback when it issufficiently similar to the peripheral information. Additionally, this foveal masking was periodic asevidenced by behavioral oscillations at around 5 Hz. Thus, we conclude that foveal-feedback supportsperipheral discrimination of familiar and novel objects by periodically processing peripheral objectinformation.

DOI: https://doi.org/10.1038/s41598-024-51710-7