Thursday, November 21, 2024
11/21/2024
Summary Cerebral (cortical) visual impairment (CVI) is the leading cause of congenital vision impairment in the United States. Yet, there remains an alarming gap in our understanding as to how observed visual perceptual deficits in these individuals relate to perinatal damage and early maldevelopment of central visual pathways and structures. Children and adolescents with CVI show striking impairments in complex motion processing (a dorsal stream function), particularly in the setting of complex dynamic environmental scenes. While impaired motion perception is an important marker of developmental vulnerability (referred to as the dorsal stream dysfunction hypothesis), standard ophthalmic clinical assessments fail to capture and fully characterize these visual deficits. Thus, in the absence of any apparent ocular abnormality, clinicians may dismiss reported perceptual difficulties, and many individuals with CVI will remain undiagnosed and never receive the timely education and rehabilitative support they need. The objective of the proposed research is to investigate the underlying neurophysiology associated with motion processing deficits in CVI. We will carry out psychophysical behavioral testing combined with multimodal neuroimaging (to characterize structural and functional connectivity along with brain network activation) in children and adolescents with CVI associated with periventricular leukomalacia (PVL). Indices of behavioral performance and neuroimaging outcomes will be compared to neurotypical controls. Our overarching hypothesis is that motion processing deficits will be associated with the maldevelopment of key visual processing pathways. However, altered patterns of functional connectivity and activation of brain networks implicated in complex motion perception may serve as indicators of compensatory neuroplasticity. In our first aim, we will assess motion processing abilities using random dot kinematograms, virtual reality simulations, and visual search tasks. In our second aim, we will characterize the integrity and topology of structural and functional connectivity networks (using high angular resolution diffusion imaging and resting state fMRI respectively) implicated with visual motion and attention processing. The third aim will investigate brain network activation (using functional MRI) in response to our behavioral task assessments. Executed by a multidisciplinary research team with strong community involvement, this combined behavioral assessment and multimodal imaging approach represents a key distinguishing innovation of the proposal. This study will provide convergent and high-level insights into the neurophysiological basis of visual motion perceptual deficits in CVI. The proposed program of research is highly significant given that uncovering brain-behavioral associations in the case of CVI represents a crucial step in establishing a neurorehabilitative framework specifically designed for the care of these children; a population that has been greatly underserved despite its important
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