Adaptation to square-wave gratings: in search of the elusive third harmonic.
Adaptation to square-wave gratings: in search of the elusive third harmonic.
复制标题
适应方波光栅：寻找难以捉摸的三次谐波。
DOI：
10.1016/0042-6989(73)90209-5
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发表时间：
1973
期刊：
影响因子：
1.8
通讯作者：
A. Weber
中科院分区：
文献类型：
--
作者：
J. Nachimias;R. Sansbury;A. Vassilev;A. Weber
Blakemore和Campbell（1969）发现，与相同周期的正弦波光栅不同，方波自适应光栅提高了频率在方波三次谐波附近的测试光栅的阈值对比度。由于其重要的轴承频率特异性的适应光栅，我们试图复制这一发现。我们的尝试是成功的两个观察者之一时，调整的方法被用来确定阈值。采用时间两择一、强迫选择的方法，个体在这方面的差异消失了。对于所有三个观察者，3 c/deg自适应方波和3 c/deg正弦波在提高9 c/deg测试光栅的对比度阈值方面同样无效，而9 c/deg自适应光栅与方波中的第三谐波匹配，将测试光栅的阈值提高了0.2 log单位。我们未能找到一致的证据表明，在一个方波的第三次谐波做任何适应无论什么质疑频率特异性的适应光栅。
BlakemoreandCampbell(1969) found that a square-wave adapting grating, unlike a sinewave grating of the same period, elevates threshold contrast for test gratings whose frequency is in the vicinity of the third harmonic in the square-wave. Because of its important bearing on the frequency-specificity of adaptation to gratings, we attempted to replicate this finding. Our attempt was successful with one of two observers when the method of adjustment was used to determine thresholds. With the temporal two alternative, forced-choice method, individual differences in this regard disappeared. For all three observers a 3 c/deg adapting square-wave and a 3 c/deg sinewave were equally ineffective in raising the contrast threshold for a 9 c/deg test grating, whereas a 9 c/deg adapting grating, matched to the 3rd harmonic in the square-wave, raised the test grating's threshold by 0.2 log units. Our failure to find consistent evidence that the third harmonic in a square-wave does any adapting whatever casts doubt on the frequency-specificity of adaptation to gratings.