Predicting the motion after-effect from sensitivity loss
Predicting the motion after-effect from sensitivity loss
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DOI：
10.1016/j.visres.2006.01.019
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发表时间：
2006-07-01
期刊：
影响因子：
1.8
通讯作者：
Solomon, J. A.
中科院分区：
文献类型：
--
作者：
Morgan, M.;Chubb, C.;Solomon, J. A.
被广泛接受的运动后效应去抑制理论认为，通过定向适应来改变对手机制的平衡点。为了了解适应后平衡点是否可以从对比度适应中预测出来，我们测量了适应移动栅格前后的阈值与对比度(即T-vs-C或勺子)函数。对于同一方向移动的测试刺激，适应使最大便利点(即倾角)向上和向右移动。对于向相反方向移动的测试，适应产生了类似的、但较小的变化。这些转变与分裂的增益控制的变化是一致的。它们也与减法抑制和半波整流一致。我们尝试使用从这些数据中得出的传感器函数来预测MAE的强度。当组合在一起时，在自适应和相反方向上移动的光栅看起来完全平衡(即，反相)，当后者被给予的对比度比基于导出的换能器所预测的大约2%时。这种轻微的预测不足可能预示着感官的重新校准。最后，我们发现，适应并没有改变这样一个事实，即低对比度刺激可以被检测到，并以类似的准确性识别它们的方向。我们得出结论，静态和动态MAE的产生主要是由于去抑制理论提出的定向调谐机构灵敏度降低所致。(C)2006爱思唯尔有限公司。保留所有权利。
The widely accepted disinhibition theory of the motion after-effect (MAE) proposes that the balance point of an opponent mechanism is changed by directional adaptation. To see if the post-adaptation balance point could be predicted from contrast adaptation, we measured threshold-vs-contrast (i.e., T-vs-C or dipper) functions, before and after adaptation to moving gratings. For test stimuli moving in the same direction, adaptation shifted the point of maximum facilitation (i.e., the dip) upwards and rightwards. For tests moving in the opposite direction, adaptation produced a similar, but smaller, shift. These shifts are consistent with a change in divisive gain control. They are also consistent with subtractive inhibition followed by half-wave rectification. We attempted to use transducer functions derived from these data to predict the strength of the MAE. When combined, gratings moving in the adapted and opposite directions appeared perfectly balanced (i.e., counterphasing) when the latter was given approximately 2% more contrast than was predicted on the basis of the derived transducers. This small under-prediction may be indicative of sensory recalibration. Finally, we found that adaptation did not alter the fact that low-contrast stimuli could be detected and their direction identified with similar accuracy. We conclude that both static and dynamic forms of MAE are primarily caused by a decreased sensitivity in directionally tuned mechanisms, as proposed by the disinhibition theory. (c) 2006 Elsevier Ltd. All rights reserved.