Invited talk by Stephen RAMANOEL

2015-09-04 at 14:00

Conference room UCL R+0


fMRI study of spatial frequency processing during scene categorization in normal and pathological aging

The aim of this work is to develop robust and rapid tools for the study of neurocognitive mechanisms involved in visual perception. More precisely, functional magnetic resonance imaging (fMRI) is used to study the projection of spatial frequencies (SF) in the visual cortex during the perception of natural scenes presented in a large portion of the visual field. Here we seek to determine the specific involvement of the different retinotopic visual areas from V1 to V4 in the different mechanisms underlying the analysis of SF, as well as the effect of different contrast normalization methods on these mechanisms. Furthermore, after studying these issues in healthy adults, we also seek to study the evolution of the visual processing of SF in both normal and pathological aging. To this aim, we can transpose different fMRI paradigms (including SF and fast retinotopic mapping) to the elderly non-pathological subjects, and also, study the plasticity of brain reorganization in pathological subjects suffering from macular degeneration. These fMRI studies on the structural and functional properties of the visual cortex are essential to distinguish cortical changes related to normal aging from those resulting from the pathophysiology of an underlying disease. In addition, these efforts are important prerequisite to the study of the functional consequences of diseases affecting either peripheral or central visual system, notably in order to measure the impact of rehabilitation programs.

Spatial Frequency; fMRI; Visual Cortex; Aging; Age-Related Macular Degeneration; Retinotopic Mapping.

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