We combine clinical, behavioral, electrophysiological, and functional imaging methods to study static and dynamic aspects of visual perception.
Routine ophthalmologic examination addresses static aspects of visual perception (e.g. visual acuity, contrast sensitivity, and colour perception). However, real-life environment deals with continuous dynamic visual stimuli. This may explain the failure of the routine ophthalmologic examination to fully diagnose the condition of patients following an optic neuritis attack. Despite recovery shown in the routine ophthalmological testing, patients following an optic neuritis attack continue to perceive difficulties in performing everyday visual tasks. In a longitudinal study on optic neuritis patients, combining behavioral tests and advanced functional imaging, we demonstrated a sustained deficit in motion perception and suggested that this deficit may explain patients’ persisting visual complaints (Raz et al., Neurology 2011).
Furthermore, we demonstrated that the impaired motion perception in the patients is associated with the level of optic nerve demyelination. Conduction velocity along the optic nerve correlated closely with dynamic visual functions, implying the need for rapid transmission of visual input to perceive motion. We suggest that motion perception may serve as a tool to assess the magnitude of myelination in the visual pathways and that it efficiently assesses the efficacy of currently developing neuro-protective and regenerative therapeutic strategies, targeting myelination in the CNS (Raz et al., Annals of Neurology 2012).
Studying the fellow clinically unaffected eye of optic neuritis patients, we argue that visual projection via this eye reflects an adaptive process. This adaptation contributes to temporal synchronization of binocular visual information and improves binocular visual functions (Levin et al., AAN abstract 2013).
Furthermore, in addition to understanding processes connected to optic neuritis, our cumulative findings in the affected and fellow eyes put forward demyelinative optic neuritis as a fine model to study temporal aspects of visual perception.