The optic chiasm is an important midline choice point where retinal ganglion cell (RGC) axons from each eye diverge to targets on both sides of the brain, setting up binocular vision. While several cues essential for guidance at the optic chiasm have been identified, it is clear other signals are required. We have begun to investigate the role of the highly related homophilic cell adhesion mole...

In order to determine the signals that initiate axon myelination in the CNS, we have chronicled the differentiation of oligodendrocytes in the rat optic nerve and related this to the time course and spatial gradient seen for optic axon myelination. By using markers specific to the varying stages of oligodendrocyte differentiation we found that oligodendrocyte progenitor cells, present throughou...

Glaucoma represents a group of neurodegenerative diseases characterized by structural damage to the optic nerve and the slow, progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is traditionally considered to be the most important risk factor for glaucoma, and treatment options for the disease have hitherto been limited to its reduction. However, visual field...

Hypothalamic and optic chiasm gliomas may be indistinguishable clinically, radiographically, and pathologically. Ten children with giant gliomas of the hypothalamus and optic pathway, all under age 2 years, had masses greater than 3 cm in diameter. Pathologically all proven cases (seven) were cytologically benign fibrillary astrocytomas. Previous authors have recognized the difficulty in distin...

During development, retinal ganglion cell axons grow from the eye through the ventral diencephalon, where axons from each eye intersect, forming the optic chiasm. The optic chiasm is associated with the formation of a bilateral projection of axons from each retina to major visual relay nuclei (Guillery et al., 1995; Mason and Sretavan, 1997). In rodents, axons from the ventral temporal retina t...

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 oculocutane...

During CNS development, combinatorial expression of transcription factors controls neuronal subtype identity and subsequent axonal trajectory. Regulatory genes designating the routing of retinal ganglion cell (RGC) axons at the optic chiasm to the appropriate hemisphere, a pattern critical for proper binocular vision, have not been identified. Here, we show that the zinc finger transcription fa...

At the optic chiasm, retinal ganglion cells (RGCs) project ipsi- or contralaterally to establish the circuitry for binocular vision. Ipsilateral guidance programs have been characterized, but contralateral guidance programs are not well understood. Here, we identify a tripartite molecular system for contralateral RGC projections: Semaphorin6D (Sema6D) and Nr-CAM are expressed on midline radial ...

PURPOSE To evaluate the radiation dose-volume effects of optic nerves and chiasm by visual psychophysical, electrophysiologic tests, and optical coherence tomography in patients with locally advanced nasopharyngeal carcinoma. MATERIALS AND METHODS A series of visual tests including visual acuity, visual field, contrast sensitivity, visual evoked potential, and optical coherence tomography wer...

Eight verified lesions of the optic chiasm were examined on 0.5 T magnetic resonance (MR) and GE 9800, 8800 computed tomographic (CT) scanners. Enlargement of the optic chiasm was demonstrated in all cases. There was some change of MR signal compared with brain in all but one case, which had no resemblance to contrast enhancement on CT scans. The signal was specific for hematoma in one case. Ab...