Gheorghiu Elena, Kingdom Frederick A A, Thai Minh-Thu, Sampasivam Lavanya
McGill Vision Research, Department of Ophthalmology, McGill University, 687 Pine Avenue W., Montreal, Quebec, Canada H3A 1A1.
Vision Res. 2009 Jul;49(14):1765-74. doi: 10.1016/j.visres.2009.04.010. Epub 2009 Apr 17.
We investigated the binocular properties of curvature-encoding mechanisms using the shape-frequency and shape-amplitude after-effects (or SFAE and SAAE). The SFAE and SAAE refer to the shifts observed in, respectively, the shape-frequency and shape-amplitude of a sinusoidal test contour following adaptation to a contour with different shape-frequency/shape-amplitude. We examined (i) the contribution of monocular versus binocular mechanisms to the SFAE and SAAE by measuring the interocular transfer of these after-effects, (ii) the stereo-depth selectivity of the after-effects and (iii) the depth selectivity of the reduction in the after-effects from texture-surround inhibition. Our results reveal that (i) both SFAE and SAAE have a high degree of interocular transfer (on average >90%), suggesting that they are mediated primarily by binocular mechanisms, (ii) neither SFAE nor SAAE are selective to stereo-defined depth and (iii) the reduction in the SFAE and SAAE from texture-surround inhibition is selective for stereo-depth. We conclude that the SFAE and SAAE are mediated by binocularly driven curvature-selective neurons that are not disparity selective in themselves but which receive inputs from neurons that are subject to depth- and orientation-selective texture-surround inhibition.
我们使用形状频率和形状幅度后效（即SFAE和SAAE）研究了曲率编码机制的双眼特性。SFAE和SAAE分别指在适应具有不同形状频率/形状幅度的轮廓后，正弦测试轮廓的形状频率和形状幅度中观察到的偏移。我们研究了：（i）通过测量这些后效的双眼间转移，单眼机制与双眼机制对SFAE和SAAE的贡献；（ii）后效的立体深度选择性；以及（iii）纹理环绕抑制导致的后效降低的深度选择性。我们的结果表明：（i）SFAE和SAAE均具有高度的双眼间转移（平均>90%），表明它们主要由双眼机制介导；（ii）SFAE和SAAE对立体定义的深度均无选择性；以及（iii）纹理环绕抑制导致的SFAE和SAAE降低对立体深度具有选择性。我们得出结论，SFAE和SAAE由双眼驱动的曲率选择性神经元介导，这些神经元本身并非视差选择性的，但接收来自受深度和方向选择性纹理环绕抑制的神经元的输入。
