Functional Plasticity in the Human Visual System Neural systems underlying learning and representation of global motion: In previous psychophysical studies of perceptual learning of a motion direction discrimination task we found that the subjects’ performance improves with practice over less than 300 trials in a single testing session, is retained over time, and is specific for the particular stimulus attributes (1). Given the time course of minutes over which this learning takes place, the neural substrates of the perceptual learning can be studied using fMRI as described here. We demonstrate performance related changes in cortical and cerebellar activity. The largest learning-dependent changes were observed in the anterior lateral cerebellum, where the extent and intensity of activation correlated inversely with psychophysical performance. After learning had occurred (a few minutes), the cerebellar activation almost disappeared; however, it was restored when the subjects were presented with a novel, untrained direction of motion for which psychophysical performance also reverted to chance level. Similar reductions in the extent and intensity of brain activations in relation to learning occurred in the superior colliculus, anterior cingulate and parts of the extrastriate cortex. The motion-direction sensitive MT complex was a notable exception, where there was an expansion of the cortical territory activated by the trained stimulus. Together, these results indicate that the learning and representation of visual motion discrimination are mediated by different, but probably interacting, neuronal subsystems. Full Report Here Back to Research last update: 12/10/98