Professor Trichur Vidyasagar
Departments of Optometry & Vision Science and Anatomy & Neuroscience and Melbourne Neuroscience Institute, University of Melbourne

Reading into top-down mechanisms in visual attention: Neural synchrony to dyslexia

Attention helps to selectively process signals related to an object of interest embedded in a cluttered world.  Our experiments in non-human primates show that this process is mediated by top-down signals from a parietal area (LIP) of the cortex that enhance responses at specific locations at earlier stages of the visual pathway such as the middle temporal area (MT).  Such modulation involves synchronized activity of LIP neurones inducing similar oscillatory activity in MT in the low gamma frequencies.  The feedback signals are seen to modulate also responses at the level of the primary visual cortex.  These results are consistent with our recent experiments on human subjects that show the dominance of spatial attention over feature-based.  Such gating of sensory inputs rapidly and at a fine spatial scale by the feedback pathways is a fundamental process in many cognitive functions such as reading. Factors that affect such spatiotemporal parsing within the visual system may form the basis for the impaired reading seen in developmental dyslexia.

Location: Level 7 Auditorium, QBI Building (#79), St.Lucia Campus
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