ISSN : 1226-9654
시신경 다발이 안구를 나가는 출구를 맹점이라고 한다. 맹점에는 감광 세포가 존재하지 않기 때문에 실질적으로 맹점에 대응하는 시각장의 정보는 입력되지 않는다. 그러나 우리는 실생활에서 맹점의 공백을 지각하지 못한다. 그 이유는 인간의 시각 체계가 맹점 주변에 제시된 정보로 맹점을 채우기(filling-in) 때문이다. 본 실험에서는 맹점 주변 정보의 신호 강도가 맹점을 채우는데 어떻게 영향을 미치는지 알아보기 위하여 참가자의 맹점 주변에 대비(contrast)와 중심와로부터 상대적 위치가 각기 다른 격자 자극을 제시하고 맹점을 채우는데 필요한 최소한의 자극 크기를 측정하였다. 그 결과 자극의 대비 강도가 강하고 중심와에 가까울수록 자극 크기가 작아도 맹점을 채울 수 있음을 발견하였다. 이는 맹점의 주변 정보가 모두 동등하게 맹점 채우기에 영향을 미치는 것이 아니며, 자극의 강도가 맹점 채우기에 중요한 요인임을 시사한다.
Blind spot is the area where optic nerves exit out of the retina. Since there is no photoreceptor in the blind spot, no visual input is present in this portion of the retina. Despite the lack of visual input, we do not realize the presence of the blind spot due to the filling-in mechanism of the human visual system. The visual system fills in the blind spot using surrounding information. We investigated the relationship between characteristics of the surrounding information and the aspect of the filling-in process of the blind spot. We varied stimuli characteristics such as contrast and the relative distance from the fovea. Participants' task was to report the smallest surrounding stimulus which could fill in the blind spot. Surrounding stimuli with higher contrast and relatively closer distance from the fovea filled in the blind spot with relatively smaller size of the stimuli. These results suggest that the signal strength of the surrounding information is an important factor in filling-in of the blind spot.
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