| dc.description.abstract | The evidence of remarkable plasticity in the adult brain suggests that 1) changes in visual sensory experience through deprivation can influence multisensory function and 2), therapies founded on plasticity e.g., perceptual learning, can facilitate rehabilitation. However, the impact of visual deprivation on multisensory integrative abilities in adult humans has not been quite explored. Second, although multisensory-based perceptual learning paradigms produce better learning outcomes compared with unisensory (e.g., visual only) paradigms, currently, the visual stimulus features (e.g., contrast) or tasks (e.g., detection) for which visual learning may benefit from multisensory facilitation have not been quite explored. Hence, the goal of my dissertation work was two-fold: first, to characterize the changes in multisensory temporal processing after brief periods of monocular deprivation in adult humans using both psychophysical and neuroimaging techniques, and second, to assess the impact of multisensory-based perceptual learning paradigms in improving visual perceptual outcomes using a simple visual contrast detection task. Findings from our first project revealed that a brief period of monocular deprivation had significantly different impact on the multisensory perceptual abilities for the deprived eye and the non-deprived eye, although this effect was short-lived. Furthermore, an electrophysiological investigation revealed that both alpha and beta oscillations were involved in the short-term monocular deprivation effects on multisensory temporal perception. For the second project, we found that incorporating task irrelevant sound in a visual contrast detection training improved visual detection performance not only in the training phase when sound was present for the multisensory group, but also after training when the sound was absent. Analysis from the perceptual template model revealed that both external noise reduction and changes in transducer nonlinearities explained performance enhancement under multisensory training, while for visual-only training, performance enhancement was explained by only external noise reduction mechanism. Taken together, these findings imply that 1) visual deprivation occurring in adult-onset low vision may influence multisensory perception and processing and thus, may contribute to the development of acquired compensatory behaviors and 2) perceptual learning paradigms that incorporate multisensory information may provide a powerful new set of rehabilitative tools in the quest to improve visual function in low vision. | |
