Shengxing Yang¹ (), Qiang Yang¹, Sreenivasan Meyyappan², George Mangun², Mingzhou Ding¹; ¹J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, ²Department of Psychology and Center for Mind and Brain, University of California Davis

The left visual field bias is a phenomenon where individuals tend to process visual information more efficiently when it is presented in their left visual field compared to their right visual field. The underlying neural mechanisms remain to be clarified. We recorded fMRI data in two experiments to examine whether neural representations of visual stimuli exhibited a left visual filed bias. In both experiments, a trial started with a cue, which instructed the participant to attend a location in either the left or the right visual field. In the first experiment, following a variable cue-target period, a grating appeared with equal probability in either the left or the right visual field, and the participant reported whether the spatial frequency of the grating was high or low if it appeared in the attended visual field and ignored the grating if it appeared in the unattended visual field. In the second experiment, at the end of the cue-target period, two rectangles appeared in the left and the right visual field, and the participant reported whether the rectangle in the attended visual field was horizontal or vertical. fMRI responses were estimated on a trial-by-trial basis and subjected to MVPA decoding analysis (high vs low spatial frequency in the first experiment and horizontal vs vertical in the second experiment). We found that in both experiments, when the attended stimuli appeared in the left visual field, the decoding accuracy in the retinotopic visual cortex was significantly higher than when the attended stimuli appeared in the right visual field, and this was the case both in the hemisphere contralateral as well as in the hemisphere ipsilateral to the attended stimuli. We have thus demonstrated that for the two experiments considered here the neural representations of visual stimuli exhibited a left visual field bias.