Similar adaptation effects on motion pattern detection and position discrimination tasks: unusual properties of global and local level motion adaptation.

Here we examine adaptation effects on pattern detection and position discrimination tasks in radial and rotational motion patterns, induced by adapting stimuli moving in the same or opposite directions to the test stimuli. Adaptation effects on the two tasks were similar, suggesting these tasks are performed by the same population of neurons. Global motion specific adaptation was then induced by presenting adaptation stimuli and test stimuli in different parts of the visual field. Again, adaptation effects on the two tasks were similar, but neither same-direction nor opposite-direction motion produced any adaptation effect on contracting motion patterns. Finally, adaptation stimuli were compared that should have similar effects on local motion processing neurons, but different effects on global motion processing neurons. Again, adaptation effects on the two tasks were similar. However, when global-level adaptation was avoided, no adaptation effects were seen with adaptation patterns moving in the opposite direction to the test pattern. Together, these last two experiments suggest that adaptation to opposite directions of motion from the test motion affects global motion processing but not local motion processing neurons.