PT  - JOURNAL ARTICLE
AU  - Rajkumar Nallour Raveendran
AU  - Katelyn Tsang
AU  - Dilraj Tiwana
AU  - Benjamin Thompson
TI  - Anodal transcranial direct current stimulation reduces collinear lateral inhibition in normal peripheral vision
AID  - 10.1101/574590
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 574590
4099  - http://biorxiv.org/content/early/2019/03/12/574590.short
4100  - http://biorxiv.org/content/early/2019/03/12/574590.full
AB  - Peripheral vision is susceptible to crowding; difficulty in segregating a target object from adjacent objects. Crowding limits visual function in individuals with central vision loss who are forced to rely on their peripheral vision. Perceptual learning can reduce crowding in peripheral vision, however intensive training is required. To assess whether modulation of crowding can be achieved within a short time-frame, we tested the hypothesis that a single 25-minute session of primary visual cortex anodal transcranial direct current stimulation (a-tDCS) would reduce lateral inhibition in peripheral vision. Lateral inhibition occurs in the primary visual cortex and may contribute to crowding. Fourteen observers with normal vision performed a 2AFC contrast detection task with flankers positioned at a distance of 2λ (lateral inhibition) or 6λ (control condition). The stimuli were presented 6° to the left of a central cross and fixation was monitored with an infra-red eye tracker. Participants each completed two randomly sequenced, single-masked stimulation sessions; real anodal tDCS and sham tDCS. For the 2λ separation condition, a-tDCS induced a significant reduction in detection threshold (reduced lateral inhibition). Sham stimulation had no effect. No effects of a-tDCS were observed for the 6λ separation condition. This result suggests that a-tDCS may be useful as a visual rehabilitation tool for individuals with central vision loss who are reliant on peripheral vision.