An ERP Study Of The Task Difficulty Modulation In Visual Perceptual Learning

Perceptual learning(PL)refers to the relatively permanent modification of perception and behavior following a sensory experience and reflect the plasticity of brain neuro(Karni and Sagi,1991;Fahle,1994;Ahissar and Hochstein,1997).Effect of task difficulty on visual perceptual learning is hot debated.Our study matches the stimulus of different task difficulty levels and record the change in learning by using event-related potentials(ERPs).19 participants were required to finish a task of orientation discrimination for 1 days and 5 days respectively.Our results show that posterior N1(130-170ms)of 4 difficulty levels are increased significantly,especially in the 3 hard tasks,although P1 did not changed statistically.The frontier P2 shows a tendency of decrease in all tasks but P2 in the posterior area has no changes in easy task and in the 3 hard tasks shows diverse changes in both short-term and long-term learning.In the easy task,the frontier N2 increases in both short-term and long-term training;in the hard tasks,it merely increases in the short-term learning significantly.In addition,P3 are not identical in different tasks but not modulated by perceptual learning.Besides these findings,we find the posterior P2 is sensitive to task difficulty greatly.Our research provides direct electrophysiological evidence for task difficulty modulation of perceptual learning-related neuroplasticity.