EVects of trial repetition in texture discrimination

Performance on the texture discrimination task improves with practice but was also shown to decrease between closely spaced sessions. Here we explored immediate changes in performance within a single session. We found that, after an initial increase, performance declined with further training within a single session. This deterioration in performance was smaller when the inter-trial interval was longer than 3 s. Performance recovered when targets were presented in new locations within the texture stimulus—thereby excluding a general fatigue process or adaptation to the stimulus light-intensity as an explanation for our Wndings. Further, the complete transfer of deterioration between eyes pointed to cortical origin. Deterioration was also found for task-irrelevant targets, indicating the involvement of a sensory mechanism. Collectively, these Wndings trace the deterioration of performance in the texture discrimination task, previously observed across several hours, to cortical events occurring during or immediately after stimulus presentation. © 2007 Published by Elsevier Ltd.