title: Long term cortical plasticity in visual retinotopic areas in humans with silent retinal ganglion cell loss.
abstract: Visual cortical plasticity induced by overt retinal lesions (scotomas) has remained a controversial phenomenon. Here we studied cortical plasticity in a silent model of retinal ganglion cell loss, documented by in vivo optical biopsy using coherence tomography. The cortical impact of non-scotomatous subtle retinal ganglion cell functional and structural loss was investigated in carriers of the mitochondrial DNA 11778G>A mutation causing Leber's hereditary optic neuropathy. We used magnetic resonance imaging (MRI) to measure cortical thickness and fMRI to define retinotopic cortical visual areas V1, V2 and V3 in silent carriers and matched control groups. Repeated Measures analysis of variance revealed a surprising increase in cortical thickness in the younger carrier group (below 21 years of age). This effect dominated in extrastriate cortex, and notably V2. This form of structural plasticity suggests enhanced plastic developmental mechanisms in extrastriate retinotopic regions close to V1 and not receiving direct retinocortical input.
authors.affiliation: Visual Neuroscience Laboratory, IBILI, Faculty of Medicine, University of Coimbra, Portugal. Electronic address: oalmeida@fmed.uc.pt.
authors.forename: Otília C
authors.initials: OC
authors.lastname: d'Almeida
authors.affiliation: Visual Neuroscience Laboratory, IBILI, Faculty of Medicine, University of Coimbra, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Mateus
authors.affiliation: Visual Neuroscience Laboratory, IBILI, Faculty of Medicine, University of Coimbra, Portugal; Coimbra University Hospital, Coimbra, Portugal.
authors.forename: Aldina
authors.initials: A
authors.lastname: Reis
authors.affiliation: Biochemistry Institute, Faculty of Medicine, University of Coimbra, Portugal; Centre for Neuroscience and Cell Biology, University of Coimbra, Portugal.
authors.forename: Manuela M
authors.initials: MM
authors.lastname: Grazina
authors.affiliation: Visual Neuroscience Laboratory, IBILI, Faculty of Medicine, University of Coimbra, Portugal. Electronic address: mcbranco@fmed.uc.pt.
authors.forename: Miguel
authors.initials: M
authors.lastname: Castelo-Branco
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006579:Heterozygote; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D029242:Optic Atrophy, Hereditary, Leber / Q000235:genetics / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D014793:Visual Cortex / Q000473:pathology*; D055815:Young Adult
keywords: CT; Cortical plasticity; Development; Ganglion cells; LGN; LHON; LPZ; Leber Hereditary Optic Neuropathy; Mitochondrial gene mutations; RGC; Retinotopic visual areas; V1; Visual loss; cortical thickness; lateral geniculate nucleus; lesion projection zone; primary visual cortex; retinal ganglion cell