PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 6947587

Amblyopia and cortical binocularity.

H Ikeda·K Tremain
View original source ↗Export metadata ↓

Abstract

Both the visual acuity of sustained-X cells in the area centralis of the retina and the binocular properties of visual cortical cells were studied in control cats, and in cats reared with divergent or convergent squint in one eye or with uniocular or binocular atropinization. The sustained-X cell acuity was normal in control cats with squint but with alternating fixation. The cellular acuity was reduced significantly in the squinting eye of the cats which lost the ability to fix with the deviating eye and in all penalized eyes of the cats regardless of whether one or both eyes had been atropinized. However, regardless of whether X cell amblyopia was present or not, all squinting cats and cats with uniocular penalization showed a significant reduction in the number of binocularly driven cortical cells. Nevertheless, the amblyopia of X cells in the retina was correlated with a loss of proportion of cortical cells driven by the amblyopic eye compared with that driven by the non-amblyopic eye. Thus amblyopia and loss of cortical binocularity (not stereo acuity) appear to have different physiological bases.

Explore related subjects

AmblyopiaAnimalsCatsDepth PerceptionFixation, OcularNeuronsRetinaVisual AcuityVisual CortexJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

H Ikeda, K Tremain. 1980. Amblyopia and cortical binocularity.. https://pubmed.ncbi.nlm.nih.gov/6947587/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

Genome-Wide and Rare Variant Association Studies of Amblyopia in Admixed American and African Ancestry Groups.

OBJECTIVE: To identify genetic variants associated with amblyopia in African (AFR) and Admixed American (AMR) ancestry groups, expanding on previous studies conducted in European ancestry. DESIGN: Retrospective ancestry-stratified genome-wide association study (GWAS) and gene-level rare variant association study (RVAS). PARTICIPANTS: Participants in the All of Us Research Program from AFR and AMR ancestry groups who had whole-genome sequencing available. Cases and controls were distinguished based on the presence of International Classification of Diseases 9/10/SNOMED diagnosis codes for amblyopia in electronic health records. This yielded ancestry-stratified subsets of 269 cases and 71 585 controls of AMR ancestry and 366 cases and 79 460 controls of AFR ancestry. METHODS: Stratified logistic regression models were adjusted for age, biological sex, and the top 10 principal components of genomic ancestry. GWAS was limited to common variants (minor allele frequency &#x2265;1%), and RVAS was limited to rare variants with coding sequence-altering effects (minor allele frequency >1%, exonic only, excluding synonymous variants) aggregated at the gene level using the SKAT algorithm. Downstream analyses of the significant variants were performed using KEGG and GO pathway analysis and STRING database queries for protein-protein interactions and gene-gene interactions. MAIN OUTCOME MEASURES: Single-nucleotide polymorphisms were determined to have genome-wide significance if P < 5e-8 in the GWAS, and genes were determined to have significant association with amblyopia in the RVAS if P < 8.0 &#xd7; 10-4. RESULTS: In the AMR GWAS, 245 unique single-nucleotide polymorphisms mapping to 97 distinct loci were identified, notably within neurodevelopmental and axonal guidance genes, including ROBO1, SEMA4B, PTPRD, NRXN1, and CAMK2D. The AFR GWAS identified 11 significant variants corresponding to 6 loci mapping primarily to long noncoding RNAs and pseudogenes. The AMR RVAS identified 15 genes, including axonal transport genes (KIF1B and KIF7) and growth factor signaling genes (EGF, ERBIN, and AKAP17A). The AFR RVAS identified a single gene, DLG2, which encodes the postsynaptic protein PSD-93, which promotes the closure of the sensitive period of neuroplasticity for vision in early childhood. CONCLUSIONS: Genetic risk architectures for amblyopia differ across ancestries but fundamentally converge on neurodevelopmental signaling, cortical synapse assembly, and sensitive period plasticity rather than ocular structural dynamics. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Amblyopia↗
PubMed1995

Influence of temperature changes on multiple sclerosis: critical review of mechanisms and research potential.

In 1890, Uhthoff studied multiple sclerosis (MS) patients who developed amblyopia following exercise, a phenomenon later discovered to be secondary to elevated body temperature from muscular activity. Six decades later, the hot bath test and various other heating reactions (HR) began to be used diagnostically. They were essentially discontinued after 1983, being replaced by more specific and safer tests and procedures. Over 80% of MS patients develop a panoply of neurological signs during hyperthermia, 60% of which are "new" to that patient. The literature contains a number of unexplained paradoxical responses of MS patients during induced hyperthermia. These challenge the current hypothesis that, in MS, hyperthermia induces a heat-linked neuro-blockade of partially demyelinated axons. Some MS patients developed signs before temperature elevations occurred; others showed clearing of signs while temperatures were elevated or were ascending. Several MS patients improved for about 3 hours after being tested, a rebound phenomenon known as "overshoot." Conversely, other MS patients developed persistent neurological deficits after hyperthermia. The etiology of HR may be multifactorial. This includes heat itself, effects of serum calcium, blockade of ion channels, circulatory changes, heat shock proteins, and unidentified humoral substances. Research techniques are suggested to continue investigations into the enigma of HR, hopefully to widen knowledge of demyelination.

Amblyopia↗