Cyclops
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CYCLOPS Glaucomatous neurodegeneration: role of optic nerve head astrocytes Using a mouse model of glaucoma, investigators showed that astrocytes at the optic nerve head myelination transition zone are critical actors in the death of ganglion cell axons. 1 Scientists documented an unexpected biological pathway that may play a role not only in glaucoma, but also in other degenerative diseases such as Parkinson’s. The authors believe their findings provide novel targets for future therapies. Improving vision in the elderly Older subjects (over 65 years of age) were given training in a perceptual learning paradigm that allowed their vision to reach a level of vision found in young adults. 2 The task involved the discrimination of textures presented at near- threshold values. The older subjects were given 2 days of one-hour sessions and tested again after 3 months. A con- trol group showed that the improvement was not because of simple practice effects or attention, but was interpreted as a change in early levels of cortical processing. Uveal melanoma I: metastasis-related mutations Scientists at Washington University examined uveal tumours and learned that metastasis was associated with mutations in the gene-encoding BRCA1-associated pro- tein 1 (BAP1) on chromosome 3. 3 The BAP1 pathway may therefore be a therapeutic target for control of meta- stasis in melanomas and other tumours. Uveal melanoma II: Oliver Sacks as patient and reporter The famed neurologist Oliver Sacks has written a new book that includes descriptions of his experiences with ocular melanoma. 4 One-third of The Mind’s Eye is devoted to his diagnosis, treatment, and vivid descriptions, accom- panied with drawings of visual phenomena (scotoma, metamorphopsia, and hallucinations) associated with the tumour in his right eye. He dedicated the book to his ocular oncologist Dr. David Abramson, who, coincident- ally was taught by Sacks in the 1960s. Myopia: reviewing the genes that may be responsible In early development, the eye’s length grows to match the optical power of the cornea and lens, a process called emme- tropization. A failure of this process results in myopia or hyperopia, with myopia being especially prevalent. Animal models of this process include chicken, mouse, and primate, and a review of gene profiling in ametropia in these species has just been published. 5 The review points out the difficul- ties in comparing across studies because of methodological differences, but it also illuminates the potential of gene expression profiling that could eventually lead to ways of normalizing refractive development in children. Duane’s retraction syndromes: updating the classifications Belgian and U.S. Investigators believe that current research on embryogenesis, genetics, imaging, and eye move- ment recording data indicates a need to update the classifica- tions of these ocular motor disorders. 6 They go further and suggest this reclassification will lead to alterations in the current modes of surgical intervention. Strabismus surgeons can read about this in a special issue of Vision Research. Adult brain plasticity: releasing the brakes Evidence continues to accumulate about the adult brain’s ability to change, even after the so-called critical period has closed. A molecular brake, known as the Lynx1 gene, has been uncovered in the neocortex of the mouse. 7 Eliminating Lynx1 in adult mice allows visual cortex plas- ticity, assessed by measuring ocular dominance changes resulting from monocular deprivation, as found in imma- ture mice. (See also the commentary on this article. 8 ) Another review of adult brain plasticity looked at interven- tions to alter amblyopia that ranged from molecular to behavioral techniques. 9 REFERENCES 1. Nguyen JV, Soto I, Kim KY, et al. Myelination transition zone astro- cytes are constitutively phagocytic and have synuclein dependent reac- tivity in glaucoma. Proc Natl Acad Sci U S A. 2011;108:1176–81. 2. Andersen GJ, Ni R, Bower JD, Watanabe T. Perceptual learning, aging, and improved visual performance in early stages of visual pro- cessing. J Vis. 2010;10:4. doi: 10.1167/10.13.4. 3. Harbour JW, Onken MD, Roberson EDO, et al. Frequent mutation of BAP1 in metastasizing uveal melanomas. Science. 2010;330:1410–13. 4. Sacks O. The Mind’s Eye. Knopf, NY, 2010. 281 pp. ISBN 9780307272089. 5. Stone RA, Khurana TS. Gene profiling in experimental models of eye growth: clues to myopia pathogenesis. Vision Res. 2010;50:2322–33. 6. Yu ¨ ksel D, Orban de Xivry JJ, Lefe `vre P. Review of the major findings about Duane retraction syndrome (DRS) leading to an updated form of classification. Vision Res. 2010;50:2334–47. 7. Morishita H, Miwa JM, Heintz N, Hensch TK. Lynx1, a cholinergic brake, limits plasticity in adult visual cortex. Science. 2010;330:1238–40. 8. Higley MJ, Strittmatter SM. Lynx for braking plasticity. Science. 2010; 330:1189–90. 9. Bavelier D, Levi DM, Li RW, Dan Y, Hensch TK. Removing brakes on adult brain plasticity: from molecular to behavioral interventions. J Neurosci. 2010;30:14964–71. Cyclops provides a singular view of the basic science literature on vision and is a sampling of what’s new and interesting. The author, Martin J. Steinbach, PhD, welcomes your feedback and suggestions, which can be sent to [email protected]. 130 CAN J OPHTHALMOL—VOL. 46, NO. 2, APRIL 2011
Transcript of Cyclops
CYCLOPS
Glaucomatous neurodegeneration: role of optic nerve
head astrocytes
Using a mouse model of glaucoma, investigators showedthat astrocytes at the optic nerve head myelination transitionzone are critical actors in the death of ganglion cell axons.1
Scientists documented an unexpected biological pathway thatmay play a role not only in glaucoma, but also in otherdegenerative diseases such as Parkinson’s. The authors believetheir findings provide novel targets for future therapies.
Improving vision in the elderly
Older subjects (over 65 years of age) were given trainingin a perceptual learning paradigm that allowed their visionto reach a level of vision found in young adults.2 The taskinvolved the discrimination of textures presented at near-threshold values. The older subjects were given 2 days ofone-hour sessions and tested again after 3 months. A con-trol group showed that the improvement was not becauseof simple practice effects or attention, but was interpretedas a change in early levels of cortical processing.
Uveal melanoma I: metastasis-related mutations
Scientists at Washington University examined uvealtumours and learned that metastasis was associated withmutations in the gene-encoding BRCA1-associated pro-tein 1 (BAP1) on chromosome 3.3 The BAP1 pathwaymay therefore be a therapeutic target for control of meta-stasis in melanomas and other tumours.
Uveal melanoma II: Oliver Sacks as patient and reporter
The famed neurologist Oliver Sacks has written a newbook that includes descriptions of his experiences withocular melanoma.4 One-third of TheMind’s Eye is devotedto his diagnosis, treatment, and vivid descriptions, accom-panied with drawings of visual phenomena (scotoma,metamorphopsia, and hallucinations) associated with thetumour in his right eye. He dedicated the book to hisocular oncologist Dr. David Abramson, who, coincident-ally was taught by Sacks in the 1960s.
Myopia: reviewing the genes that may be responsible
In early development, the eye’s length grows to match theoptical power of the cornea and lens, a process called emme-tropization. A failure of this process results in myopia orhyperopia, with myopia being especially prevalent. Animalmodels of this process include chicken, mouse, and primate,and a review of gene profiling in ametropia in these specieshas just been published.5 The review points out the difficul-ties in comparing across studies because of methodologicaldifferences, but it also illuminates the potential of gene
expression profiling that could eventually lead to ways ofnormalizing refractive development in children.
Duane’s retraction syndromes: updating the
classifications
Belgian and U.S. Investigators believe that currentresearch on embryogenesis, genetics, imaging, and eye move-ment recording data indicates a need to update the classifica-tions of these ocular motor disorders.6 They go further andsuggest this reclassification will lead to alterations in thecurrent modes of surgical intervention. Strabismus surgeonscan read about this in a special issue of Vision Research.
Adult brain plasticity: releasing the brakes
Evidence continues to accumulate about the adultbrain’s ability to change, even after the so-called criticalperiod has closed. A molecular brake, known as the Lynx1gene, has been uncovered in the neocortex of the mouse.7
Eliminating Lynx1 in adult mice allows visual cortex plas-ticity, assessed by measuring ocular dominance changesresulting from monocular deprivation, as found in imma-ture mice. (See also the commentary on this article.8)Another review of adult brain plasticity looked at interven-tions to alter amblyopia that ranged from molecular tobehavioral techniques.9
REFERENCES
1. Nguyen JV, Soto I, Kim KY, et al. Myelination transition zone astro-cytes are constitutively phagocytic and have synuclein dependent reac-tivity in glaucoma. Proc Natl Acad Sci U S A. 2011;108:1176–81.
2. Andersen GJ, Ni R, Bower JD, Watanabe T. Perceptual learning,aging, and improved visual performance in early stages of visual pro-cessing. J Vis. 2010;10:4. doi: 10.1167/10.13.4.
3. Harbour JW,OnkenMD,Roberson EDO, et al. Frequentmutation ofBAP1 in metastasizing uveal melanomas. Science. 2010;330:1410–13.
4. Sacks O. The Mind’s Eye. Knopf, NY, 2010. 281 pp. ISBN9780307272089.
5. Stone RA, Khurana TS. Gene profiling in experimental models of eyegrowth: clues to myopia pathogenesis. Vision Res. 2010;50:2322–33.
6. Yuksel D, Orban de Xivry JJ, Lefevre P. Review of the major findingsabout Duane retraction syndrome (DRS) leading to an updated formof classification. Vision Res. 2010;50:2334–47.
7. Morishita H, Miwa JM, Heintz N, Hensch TK. Lynx1, a cholinergicbrake, limits plasticity in adult visual cortex. Science. 2010;330:1238–40.
8. HigleyMJ, Strittmatter SM. Lynx for braking plasticity. Science. 2010;330:1189–90.
9. BavelierD, LeviDM, Li RW,Dan Y,HenschTK.Removing brakes onadult brain plasticity: from molecular to behavioral interventions.J Neurosci. 2010;30:14964–71.
Cyclops provides a singular view of the basic science literature onvision and is a sampling of what’s new and interesting. Theauthor, Martin J. Steinbach, PhD, welcomes your feedbackand suggestions, which can be sent to [email protected].
130 CAN J OPHTHALMOL—VOL. 46, NO. 2, APRIL 2011
