title: Neural correlates of visual search in patients with hereditary retinal dystrophies.
abstract: In patients with central visual field scotomata a large part of visual cortex is not adequately stimulated. We investigated evidence for possible upregulation in cortical responses in 22 patients (8 females, 14 males; mean age 41.5 years, range 12-65 years) with central visual field loss due to hereditary retinal dystrophies (Stargardt's disease, other forms of hereditary macular dystrophies and cone-rod dystrophy) and compared their results to those of 22 age-matched controls (11 females, 11 males; mean age, 42.4 years, range, 13-70 years). Using functional magnetic resonance imaging (fMRI) we recorded differences in behavioral and BOLD signal distribution in retinotopic mapping and visual search tasks. Patients with an established preferred retinal locus (PRL) exhibited significantly higher activation in early visual cortex during the visual search task, especially on trials when the target stimuli fell in the vicinity of the PRL. Compared with those with less stable fixation, patients with stable eccentric fixation at the PRL exhibited greater performance levels and more brain activation.
authors.affiliation: Institute of Psychology, University of Regensburg, Germany.
authors.forename: Tina
authors.initials: T
authors.lastname: Plank
authors.forename: Jozef
authors.initials: J
authors.lastname: Frolo
authors.forename: Fatima
authors.initials: F
authors.lastname: Farzana
authors.forename: Sabine
authors.initials: S
authors.lastname: Brandl-Rühle
authors.forename: Agnes B
authors.initials: AB
authors.lastname: Renner
authors.forename: Mark W
authors.initials: MW
authors.lastname: Greenlee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001070:Appetitive Behavior / Q000502:physiology*; D001931:Brain Mapping; D002648:Child; D015862:Choroid Diseases / Q000503:physiopathology; D017352:Echo-Planar Imaging; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D007858:Learning / Q000502:physiology; D008268:Macular Degeneration / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D058499:Retinal Dystrophies / Q000235:genetics / Q000503:physiopathology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology; D012607:Scotoma / Q000503:physiopathology*; D000080362:Stargardt Disease; D055815:Young Adult