5 Aftereffect Experiments

  Using an orientation map apparently much like those in chapter 4, humans experience tilt aftereffects that vary systematically with the angle between test and adaptation lines. The longer one adapts to an orientation, the further away similar orientations seem to be, and the closer distant orientations seem to be. These perceptions have been measured in some detail in humans, and since they can be measured in the RF-LISSOM model as well, they offer an opportunity to put the inhibition theory of the TAE to the test.

This chapter will describe how the orientation map from the previous chapter was set up to test for the TAE, and it will show that the model exhibits quite realistic tilt aftereffects. It will also show precisely how those effects arise in the model, with detail as yet unavailable in the cortex. This analysis provides testable predictions for future biological and psychophysical studies. Chapter 6 will discuss the significance of these results and propose other areas for investigation.