Fatigue and structural change: two consequences of visual pattern adaptation.

In a tilt aftereffect (TAE) paradigm, 2 min of adaptation produced an aftereffect that decayed almost completely within 4 min. Four minutes of adaptation produced a TAE that lasted more than 2 wk. Two modes of adaptation contribute to the TAE and account for other aftereffects: short-term fatigue, produced very quickly and long-term structural change, requiring more extended adaptation.