Disease relevance of Visual Pathways

• At 48 hours of development, expression of nrf is detected in the ganglion cell layer, in the neurons of the inner nuclear layer, and in the optic nerve and optic tracts, and, at 72 hours of development, is no longer detectable by in situ hybridization [1].
• Adrenoleukodystrophy is an X-linked metabolic disorder with very-long-chain fatty acid (VLCFA) accumulation and multifocal nervous system demyelination, often with early involvement of visual pathways [2].
• Visual evoked potential testing was performed on 15 Negro carriers of the gene for tyrosinase positive oculocutaneous albinism in order to detect whether they have the same visual pathway decussation anomalies as do homozygotes [3].
• CONCLUSIONS: In patients affected by clinically definite MS without history of optic neuritis and no visual symptoms, there is a large prevalence of visual pathway involvement that can be diagnosed only by performing multiple tests [4].
• Oral acrylamide produces axonal swelling and later degeneration and gliosis in the distal optic tract, especially within the lateral geniculate nucleus, of macaque monkeys [5].

Psychiatry related information on Visual Pathways

• In the superior colliculi of cats anesthetized with ketamine, 84% of identified output cells of the deep layers could be driven by shocks to the contralateral optic disk, optic chiasm, or ipsilateral optic tract; 75% of these deep-layer cells had response latencies reflecting a polysynaptic influence of retinal Y-cells [6].
• Functional integrity of benzodiazepine receptors of the geniculo-striate visual pathways in Creutzfeldt-Jakob disease. A pharmacological evoked potential study [7].
• Treatment with biotin results in pronounced, rapid, clinical and biochemical improvement, but some patients have residual neurological damage comprising neurosensory hearing loss, visual pathway defects, ataxia, and mental retardation [8].

High impact information on Visual Pathways

• For some years, evidence has accumulated that there are GABA receptors, especially prominent along visual pathways, which are neither antagonized by bicuculline nor activated by baclofen, but are activated by certain conformationally restricted analogues of GABA, including cis-4-aminocrotonic acid (CACA) [9].
• Patterned activity, synaptic convergence, and the NMDA receptor in developing visual pathways [10].
• Age-related changes underlie switch in netrin-1 responsiveness as growth cones advance along visual pathway [11].
• Axon sorting in the optic tract requires HSPG synthesis by ext2 (dackel) and extl3 (boxer) [12].
• This genetic evidence that heparan sulfate proteoglycan function is required for optic tract sorting provides clues to begin understanding the underlying molecular mechanisms [12].

Chemical compound and disease context of Visual Pathways

• 1. Single-unit extracellular recordings of optic tract fibers were used to study ganglion cell (GC) response properties of the intact cat eye before and after the intravitreal injection of haloperidol or SCH23390, dopamine-specific antagonists [13].
• When any patient with thalassemia major requiring multiple transfusions develops visual failure, appropriate studies should be performed to rule out compression of visual pathways by ectopic marrow, especially if the patient is receiving deferoxamine [14].
• Chronic hypokalemia did not influence the concentration or distribution of digoxin in the optic tract [15].
• Decreased photoreceptor function as well as ganglion cell loss as indicated by pathological flash VEPs may reflect a cytotoxic impact of homocysteine on neurons of the visual pathway [16].
• Positron emission tomography and 18F-fluorodeoxyglucose for the detection of visual pathway abnormalities in albinism [17].

Biological context of Visual Pathways

• Two-dimensional polyacrylamide gel electrophoresis and fluorography revealed that the induced heat shock protein underwent axonal transport from retinal ganglion cells into the optic nerve and subsequently down the contralateral optic tract to synaptic termini in the visual projection area [18].
• Blockade of GABAergic transmission revealed a field EPSP in response to optic tract stimulation which was sensitive to the NMDA antagonist AP5 [19].
• The manifestations of bilirubin encephalopathy include disturbances in the visual pathway (visual gaze paralysis and distorted visual perception) [20].
• Findings indicate that 3 alpha, 5 alpha-P acts as an allosteric modulator only for low affinity GABA binding sites, displaying an age-dependent profile probably related to plastic events during visual pathway development [21].
• We have shown that circadian rhythms of rats with monosodium glutamate-induced neurotoxic damage to visual pathways persist under constant light, and hypothesized that monosodium glutamate damaged the retinogeniculate pathway, thus preventing constant light-induced arrhythmicity [22].

Anatomical context of Visual Pathways

• We resolved four major Coomassie Blue-stained proteins with apparent molecular masses of 197, 200, 205, and 210 kD on high resolution one-dimensional SDS-polyacrylamide gels of mouse optic axons (optic nerve and optic tract) [23].
• In contrast to all other retinal axons they seem to be deflected from the midline of the optic chiasm and thereby led into the ipsilateral optic tract [24].
• GAP-43 mediates retinal axon interaction with lateral diencephalon cells during optic tract formation [25].
• Retinal ganglion cell axon progression from the optic chiasm to initiate optic tract development requires cell autonomous function of GAP-43 [26].
• MAP2 immunoreactivity was present in astrocytes of the optic chiasm, but was absent from astrocytes in the optic tract [27].

Associations of Visual Pathways with chemical compounds

• During axonal regeneration, optic tract glia show increased incorporation of both thymidine and amino acids [28].
• The distinctive properties of rho receptors are very similar to those of bicuculline-insensitive GABA-gated chloride channels identified in retina, suggesting a molecular basis for this form of GABA receptor in visual pathways [29].
• Inhibition of protein tyrosine kinases impairs axon extension in the embryonic optic tract [30].
• A rat model was developed in which optic tracts were enhanced by manganese ions [31].
• By acting through retinal nicotinic acetylcholine receptors (nAChRs), acetylcholine plays an important role in the development of both the retina and central visual pathways [32].

Gene context of Visual Pathways

• Long-term survival of most RGCs in culture can be promoted by a combination of trophic factors normally produced along the visual pathway, including BDNF, CNTF, IGF1, an oligodendrocyte-derived protein, and forskolin [33].
• Thus, Foxd1 plays a dual role in the establishment of the binocular visual pathways: first, in specification of the VT retina, acting upstream of proteins directing the ipsilateral pathway; and second, in the patterning of the developing ventral diencephalon where the optic chiasm forms [34].
• Electrophysiological studies demonstrated that Vsx1 mutant mice have defects in their cone visual pathway, whereas the rod visual pathway was unaffected [35].
• Cells expressing both MBP and GFAP were also identified in optic tract [36].
• Furthermore, the axons with elevated FGFR expression in the optic tract have a posterior border of rich FGFR expression in the lateral part of the diencephalon [37].

Analytical, diagnostic and therapeutic context of Visual Pathways

• 1. Intracellular and patch-clamp recordings were obtained from thalamocortical (TC) cells in the rat and cat dorsal lateral geniculate nucleus (dLGN) in vitro to study the role of N-methyl-D-aspartate (NMDA) and non-NMDA receptors in the synaptic potential and burst firing evoked by electrical stimulation of the optic tract [38].
• The distribution of neuronal elements containing immunoreactive somatostatin (I-SRIF) in the rat central visual pathway was examined by light-microscopic immunocytochemistry [39].
• Whole cell recordings showed that monosynaptic postsynaptic currents (PSCs) evoked in LGNv neurons by optic tract stimulation were blocked by glutamate receptor antagonists [40].
• As a diagnostic test of visual pathway involvement in MS, tangent screen examination compares favourably with more sophisticated methods [41].
• PURPOSE: The authors emphasize the potential for the development of anterior visual pathway gliomas, evidenced by computed tomography (CT) or magnetic resonance imaging (MRI) scans, in neurofibromatosis type 1 (NF1) patients who previously had normal neuroimaging studies [42].

References