Abstract
The role of attention in perceptual learning is a focus question during recent years. However, the brain mechanism of attentional modulation on visual perceptual learning is still unclear. By recording event-related potentials from human adults, the present study investigated how top-down attention modulates visual perceptual learning. 30 subjects were randomly divided into two groups: active & passive learning group. Each subject received 1.5 h's training when ERP was recorded. Subjects of active learning group were trained to discriminate the line orientation, while those of passive learning group just passively viewed the stimuli used in active learning group. All the subjects received tests on line orientation discrimination task just before and after the training, as well as on the next day. Behavioral results showed that, subjects of active training group obtained larger improvement of performance than those of passive learning group. While the learning effect of passive group could transfer to different stimulus orientations and occurred mainly after the training, that of active group was orientation-specific and occurred mainly during the training. ERP results showed that, for passive learning group, both posterior P1(90-110ms) and N1(120-160 ms) decreased in amplitude along 1.5h's training, while posterior P2(210-250 ms) did not change. For the active group, however, P1 did not change; N1 decreased but the decrement was smaller than that of passive group; while P2 increased in amplitude with training. The present study implies that top-down attention does modulate the short-term perceptual learning, leading to the stimulus-specific learning effect in behavioral performance as well as increments of neural activity which are opposite to the sensory adaptation effects caused by stimuli repetition and originate from quite early stage of visual processing, within 100 ms after stimulus onset.
This work was supported by the National Nature Science Foundation of China grants (30570605) and the Open Project Grant of the State Key Laboratory of Brain and Cognitive Science, China.