| Oscillatory motion but not pattern reversal elicits monocular motion VEP biases in infantile esotropia. | |
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MedLine Citation:
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PMID: 10343872 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Patients with early disruptions of binocularity show cortical directional asymmetries in their steady state monocular VEP response to oscillatory motion. The VEP directional asymmetry is characterized by significant first harmonic components that show a 180 degrees difference in the response phase between the two eyes. By contrast, the normal response is dominated by even-order response harmonics, although some normal observers also have measurable responses at the first harmonic. Experiments and simulations were conducted to determine if the first harmonic in patients could reasonably be attributed to direction selective mechanisms. A secondary goal was to determine whether the first harmonic response of normals was also due to imbalances in direction selective mechanisms. Monocular steady state VEPs were elicited by oscillating 3 c/deg gratings presented at 6 and 10 Hz in normal observers and observers with infantile esotropia. Responses were also obtained to phase-reversing gratings of the same spatial and temporal frequencies. Phase reversal eliminated the majority of first harmonic responses which were recorded for normal observers to oscillatory motion. However, phase reversal did not elicit the cortical motion asymmetry in infantile esotropia. Modeling results suggest that the first harmonic response to oscillatory motion arises due to non-linearities in both direction selective and non-direction-selective mechanisms, with the latter being dominant in patients with early onset strabismus. |
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Authors:
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S J Shea; A Chandna; A M Norcia |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Vision research Volume: 39 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 1999 May |
Date Detail:
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Created Date: 1999-06-14 Completed Date: 1999-06-14 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0417402 Medline TA: Vision Res Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 1803-11 Citation Subset: IM |
Affiliation:
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Department of Orthoptics, University of Liverpool, UK. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Esotropia / physiopathology* Evoked Potentials, Visual* Humans Infant Models, Neurological Motion Perception / physiology* Pattern Recognition, Visual / physiology* Vision, Monocular / physiology |
| Grant Support | |
ID/Acronym/Agency:
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EY 06579/EY/NEI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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