title: Changes in brain morphology in albinism reflect reduced visual acuity.
abstract: Albinism, in humans and many animal species, has a major impact on the visual system, leading to reduced acuity, lack of binocular function and nystagmus. In addition to the lack of a foveal pit, there is a disruption to the routing of the nerve fibers crossing at the optic chiasm, resulting in excessive crossing of fibers to the contralateral hemisphere. However, very little is known about the effect of this misrouting on the structure of the post-chiasmatic visual pathway, and the occipital lobes in particular. Whole-brain analyses of cortical thickness in a large cohort of subjects with albinism showed an increase in cortical thickness, relative to control subjects, particularly in posterior V1, corresponding to the foveal representation. Furthermore, mean cortical thickness across entire V1 was significantly greater in these subjects compared to controls and negatively correlated with visual acuity in albinism. Additionally, the group with albinism showed decreased gyrification in the left ventral occipital lobe. While the increase in cortical thickness in V1, also found in congenitally blind subjects, has been interpreted to reflect a lack of pruning, the decreased gyrification in the ventral extrastriate cortex may reflect the reduced input to the foveal regions of the ventral visual stream.
authors.affiliation: FMRIB Centre, John Radcliffe Hospital, Oxford, United Kingdom; Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom. Electronic address: holly.bridge@clneuro.ox.ac.uk.
authors.forename: Holly
authors.initials: H
authors.lastname: Bridge
authors.affiliation: MRC Cognition and Brain Sciences Unit, Cambridge, United Kingdom.
authors.forename: Elisabeth A H
authors.initials: EA
authors.lastname: von dem Hagen
authors.affiliation: FMRIB Centre, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Davies
authors.affiliation: FMRIB Centre, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Claire
authors.initials: C
authors.lastname: Chambers
authors.affiliation: Department of Psychology, University of York, United Kingdom.
authors.forename: Andre
authors.initials: A
authors.lastname: Gouws
authors.affiliation: Department of Ophthalmology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoffmann
authors.affiliation: Department of Psychology, University of York, United Kingdom; Centre for Neuroscience, Hull York Medical School, University of York, York, United Kingdom.
authors.forename: Antony B
authors.initials: AB
authors.lastname: Morland
mesh_terms: D000328:Adult; D000368:Aged; D000417:Albinism / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D014786:Vision Disorders / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult