From inefficient to pop-out visual search in one week

We investigated changes in brain activity while participants learned to perform a visual conjunction search task over eight successive days. In an eventrelated functional magnetic resonance imaging (fMRI) experiment, subjects searched for a red-green disk amongst many mirror-symmetric green-red distractors. Over sessions, accuracy increased and search-time decreased, indicative of perceptual learning and popout. This behavioral change was correlated with a decrease in neuronal activation in frontal and parietal cortex and an increase in activity in early visual areas during search. Training was specific to the targetdistractor stimuli and did not transfer to other configurations. Our findings suggest that difficult visual search can be learned within a few days and that the trained skill is associated with distinct changes in activation in occipital, parietal and frontal cortex.