For the orientation adaptation to stimulus of angle , substituting equation (10) into equation (17), it is not difficult to derive that the network response to stimulus of angle 0 (vertical) is changed to

in which is the feedforward tuning width chosen to be and is the parameter of the strength of decorrelation feedback.

The theoretical curve of perceived orientation is derived by assuming the maximum likelihood of the the neural population, i.e., the perceived angle is the angle at which is maximized. It is shown in figure 5 (right). The solid line is the theoretical curve and the experimental data come from [3] (they did not give the errors, the error bars are of our estimation ). The parameter obtained through fit is the strength of decorrelation feedback: .

**Figure 5:**
*
Quantitative comparison of the theoretical predictions with the
experimental data of orientation contrast (left) and orientation
adaptation (right).
*

It is very interesting that we can derive a relationship which is independent of the parameter of the strength of decorrelation feedback ,

in which is the adaptation angle at which the tilt aftereffect is most significant and is the perceived angle.