Lawton T B, Tyler C W
Nano Tech Services, Channel Islands Harbor, CA 93035.
Vision Res. 1994 Mar;34(5):659-67. doi: 10.1016/0042-6989(94)90020-5.
We investigated the potential role of retinal X and cortical simple cells in determining human psychophysical detection performance under contrast masking conditions. Since both X and simple cells exhibit a null phase, the phase of a background mask should affect the visibility of a test grating processed by such cells. Sinusoidal test gratings of either 1 or 7 c/deg were presented as a sustained or transient increment against a background mask of the same size and spatial frequency at either 0 or 90 deg phase. For background contrasts from 0.5% up to 40%, psychophysical contrast sensitivity was phase-independent for all conditions. Therefore, either (1) contrast threshold is mediated by cells with non-linear spatial summation properties, such as Y or complex cells, or (2) the masking effect of the background occurs after a phase-insensitive combination or pooling of simple cell responses in the cortex.
我们研究了视网膜X细胞和皮层简单细胞在对比度掩蔽条件下对人类心理物理检测性能的潜在作用。由于X细胞和简单细胞均表现出零相位，背景掩模的相位应会影响由此类细胞处理的测试光栅的可见性。以1或7周/度的正弦测试光栅作为持续或瞬态增量，呈现于具有相同尺寸和空间频率、相位为0或90度的背景掩模上。对于0.5%至40%的背景对比度，在所有条件下心理物理对比度敏感度均与相位无关。因此，要么（1）对比度阈值由具有非线性空间总和特性的细胞（如Y细胞或复杂细胞）介导，要么（2）背景的掩蔽效应发生在皮层中简单细胞反应的相位不敏感组合或汇总之后。
