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Abnormal lateral geniculate nucleus and optic chiasm in human albinism
Author(s) -
Mcketton Larissa,
Kelly Krista R.,
Schneider Keith A.
Publication year - 2014
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.23565
Subject(s) - optic chiasm , albinism , lateral geniculate nucleus , decussation , biology , retina , neuroscience , optic chiasma , anatomy , geniculate , optic tract , retinal ganglion cell , optic nerve , oculocutaneous albinism , thalamus , ophthalmology , medicine , nucleus , paleontology
Our objective was to measure how the misrouting of retinal ganglion cell (RGC) fibers affects the organization of the optic chiasm and lateral geniculate nuclei (LGN) in human albinism. We compared the chiasmal structures and the LGN in both pigmented controls and patients with albinism by using high‐resolution structural magnetic resonance imaging (MRI). We studied 12 patients with oculocutaneous albinism and 12 age‐matched pigmented controls. Using a 3T MRI scanner, we acquired a T 1 ‐weighted three‐dimensional magnetization‐prepared rapid gradient‐echo (MPRAGE) image of the whole brain, oriented so that the optic nerves, chiasm, and tracts were in the same plane. We acquired multiple proton density‐weighted images centered on the thalamus and midbrain, and averaged them to increase the signal, enabling precise manual tracing of the anatomical boundaries of the LGN. Albinism patients exhibited significantly smaller diameters of the optic nerves, chiasm and tracts, and optic chiasm and LGN volume compared with controls ( P < 0.001 for all). The reductions in chiasmal diameters in the albinism compared with the control group can be attributed to the abnormal crossing of optic fibers and the reduction of RGCs in the central retina. The volume of the LGN devoted to the center of the visual field may be reduced in albinism due to fewer RGCs representing the area where the fovea would normally lie. Our data may be clinically useful in addressing how genetic deficits compromise proper structural and functional development in the brain. J. Comp. Neurol. 522:2680–2687, 2014. © 2014 Wiley Periodicals, Inc.