| Summary: | Perceptual learning is the ability to improve performance of a perceptual task, with repeated practice. The concept of perceptual learning in the adult visual system has been established for many years, however, the neural mechanisms which mediate it have proved complex to unravel. Improved understanding could be used to guide novel rehabilitative strategies for those with damage to the brain which affects the primary visual cortex (V1) in the occipital lobe. Motion perception learning is thought to involve the brain area hMT+, which is located in the parieto-temporo- occipital cortex, distal from V1. It is possible that motion perception training may improve the vision or subjective quality of life for individuals with damage to V1. This project initially looked at the effect of motion perception training in healthy individuals, in order to establish and quantify the potential behavioural and neural impact of behavioural training. A five-day motion perception training paradigm applied in these experiments produced robust improvement of motion perception in healthy participants. This learning was found to be partially transferable to untrained regions of the visual field. If the training timecourse was reduced to a single day, the location specificity of learning effects was increased significantly. Functional MRI analysis indicated that the motion perception training paradigm applied here altered activity at extrastriate visual areas and frontotemporal decision areas. When motion perception training was combined with brain stimulation, it was shown that 20 minutes of anodal transcranial direct current stimulation (tDCS) over hMT+ had no impact on learning magnitude or timecourse. Finally, the motion perception training paradigm was applied as a case study in a patient with damage to V1. The results were promising but inconclusive with such a minimal dataset. Motion perception training produces robust improvements in perception in healthy individuals, which are likely mediated by visual extrastriate and decision-making areas of the brain. As such, motion perception training shows promise, with further development, as an avenue for rehabilitation of the visual system and visual perception following damage to the primary visual cortex.
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