Abnormal visual projection in a human albino studied with functional magnetic resonance imaging and visual evoked potentials.
The albino visual pathway is abnormal in that many fibres from the temporal retina project to the contralateral visual cortex. The visual projections in a human albino and a control have been investigated with fMRI and VEP during independent visual stimulation of both hemifields. Activity in the occipital cortex in the normal was contralateral to the stimulated visual field, whereas it was contralateral to the stimulated eye in the albino, independent of the stimulated visual field. Thus, the albino visual cortex is activated not only by stimulation in the contralateral visual field, but also by abnormal input representing the ipsilateral visual field. These novel findings help elucidate the nature of albino misrouting.
Morland
A B
AB
Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 OEX, UK. a.morland@rhbnc.ac.uk
Hoffmann
M B
MB
Neveu
M
M
Holder
G E
GE
D016115:Albinism, Oculocutaneous / Q000150:complications* / Q000503:physiopathology; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014793:Visual Cortex / Q000002:abnormalities* / Q000473:pathology / Q000502:physiology; D014795:Visual Pathways / Q000002:abnormalities* / Q000473:pathology / Q000502:physiology