Feature difference task

In the feature difference task, all dots in the random-dot stereogram were correlated and given a disparity. The surrounding disparity was presented at a crossed (near) disparity of 12 arcmin and was fixed for all trials. The central target plane varied relative to this plane, and appeared either 6, 18, 30, 60, 240 arcsec in front or behind this plane. We asked participants to judge the depth of the central plane relative to its surround while undergoing functional imaging of the visual cortex.

在特征差异任务中，所有随机点立体图（random-dot stereogram）内的圆点均具有相关性，并被赋予视差（disparity）。环绕背景的视差固定为12弧分的交叉（近处）视差，且在所有实验试次中保持不变。中央靶平面相对于该环绕平面发生偏移，可位于环绕平面前方6、18、30、60、240弧秒处，或后方对应位置。本实验在对视觉皮层（visual cortex）进行功能成像（functional imaging）的同时，要求被试判断中央平面相对于环绕背景的深度。