Comprehensive frameworks of perceptual learning

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Visual perceptual learning (VPL) is defined as a long-term increase in visual performance as a result of visual experiences. The purpose of the proposed project entitled “Comprehensive frameworks of perceptual learning” is to advance the uncovering of the mechanisms underlying VPL and the basic mechanisms underlying visual and brain plasticity. This may, in turn, lead to interventions that are able to ameliorate diseases affecting vision and other pathological or age-related visual declines. We have identified three issues that must be resolved. First, there are contradictory interpretations of studies as to whether or not task-relevant VPL (R-VPL), defined as VPL of a feature relevant to a given task, is associated with a low- or higher-level stage in visual processing. A second issue involves whether R-VPL and task-irrelevant VPL (I-VPL), defined as VPL of a feature not relevant to a given task, are related to each other and, if they are, what the mechanisms are that connect them. A third issue is that there is no systematic research to test whether VPLs of different features (e.g., motion and shape) have the same underlying mechanism(s). To investigate these two issues, We will test the following three specific aims examining how local and global features are learned, using psychophysics and the online fMRI decoded neurofeedback. Specific Aim 1 will address the question as to which stage in the visual/brain processing and what mechanisms underlie R-VPL of motion. Hypothesis (H)1a: R-VPL of motion consists of both active plasticity developed with conscious effort and passive plasticity developed without conscious effort. H1b: Different types of plasticity in VPL of motion occur at different stages in visual processing as well as in different phases during the time course of learning. Specific Aim 2 will address the similarities between I-VPL and R-VPL of motion. H2a: The plasticity underlying I-VPL of motion is similar to passive plasticity in R-VPL of motion. H2b: I-VPL of motion occurs at the same phase in the timecourse of learning as passive plasticity in R-VPL of motion. Specific Aim 3 will examine how much the mechanisms involved in the VPL of motion can be generalized to VPL of shape of the target stimulus. H3a: There are passive and active plasticity in VPL of shape. H3b: Passive and active plasticity in VPL of shape occurs in different brain areas at different phases in the timecourse of learning. Through these experiments, we aim to provide important information toward a comprehensive framework to integrate and compromise controversies over VPL. !