Bertini, C., Grasso, P. A., & Làdavas, E.
The role of the retino-colliculo-extrastriate pathway in visual awareness and visual field recovery
Neuropsychologia, 90, 72–79
Patients with visual ﬁeld defects resulting from post-chiasmatic lesions experience loss of visual function in up to one half of their visual ﬁeld, with consequent impairments in their daily life activities. Therefore, effective strategies for compensating for the visual ﬁeld loss are of great clinical relevance. After lesions to the primary visual pathway -which conveys visual information from the retina to the lateral geniculate nucleus, the optic radiations and, then, to the striate cortex-an alternative visual pathway, which projects from the superior colliculus to the extrastriate cortex, is usually spared in patients with visual ﬁeld defects. In the present review, evidence for spared functioning of this alternative pathway in patients with visual ﬁeld defects will be presented, both in terms of residual visual abilities, without awareness, for stimuli presented in the blind ﬁeld, and the ability to integrate unseen visual signals presented in the blind ﬁeld with concurrent auditory stimuli. Crucially, this review will discuss how the spared retinocolliculo-extrastriate pathway might be a useful tool for compensating for the loss of visual perception. Accordingly, evidence for the compensatory effects of systematic multisensory audio-visual stimulation in patients with visual ﬁeld defects will be reviewed.