Functional changes in the human cortex over the course of visual perceptual learning

In this study we assessed functional changes through visual perceptual learning with bisection discrimination task. Before learning, after third session of learning and after learning ended, behavioral threshold and fMRI data has been collected. Our results showed that while participants showed threshold decrease in the midlearning session, the post-learning thresholds are turned to pre-learning levels. These results might be due to fatigue which caused by our experiment. Besides to training condition, we also tested location and task specificity. The results showed that only 150◦polar angle location showed significant change between sessions. Along with the behavioral data, we collected task-based fMRI data while participants performing training and control conditions in the scanner. The analysis showed task-based BOLD response changed with session. However, post-hoc tests did not reveal significant results. The resting-state functional connectivity analysis showed that the functional connectivity between V1 and V2 regions is significantly increased. The Post Hoc analysis showed significant change in the 210◦and 150◦polar angle conditions. The changes in the behavioral and functional connectivity measurements at 150◦polar angle conditions, these results might indicate the effect of the inter-hemispheric connections. Moreover, our analysis on resting state data also revealed that, while there is no change between pre-learning and mid-learning sessions, connectivity changes significantly in the post-learning session compared to other sessions. This finding supports the idea that functional connectivity changes related to perceptual learning might be occurring at the late phases of the learning. Overall, to rule out the confounds in the behavioral measurements and to link the behavioral data with the neural data, additional measurements should be taken in the future.