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Article: Incomplete cortical reorganization in macular degeneration

TitleIncomplete cortical reorganization in macular degeneration
Authors
Issue Date2010
PublisherAssociation for Research in Vision and Ophthalmology. The Journal's web site is located at http://www.iovs.org
Citation
Investigative Ophthalmology And Visual Science, 2010, v. 51 n. 12, p. 6826-6834 How to Cite?
AbstractPURPOSE. Activity in regions of the visual cortex corresponding to central scotomas in subjects with macular degeneration (MD) is considered evidence for functional reorganization in the brain. Three unresolved issues related to cortical activity in subjects with MD were addressed: Is the cortical response to stimuli presented to the preferred retinal locus (PRL) different from other retinal loci at the same eccentricity? What effect does the role of age of onset and etiology of MD have on cortical responses? How do functional responses in an MD subject's visual cortex vary for task and stimulus conditions? METHODS. Eight MD subjects-four with age-related onset (AMD) and four with juvenile onset (JMD)-and two agematched normal vision controls, participated in three testing conditions while undergoing functional magnetic resonance imaging (fMRI). First, subjects viewed a small stimulus presented at the PRL compared with a non-PRL control location to investigate the role of the PRL. Second, they viewed a full-field flickering checkerboard compared with a small stimulus in the original fovea to investigate brain activation with passive viewing. Third, they performed a one-back task with scene images to investigate brain activation with active viewing. RESULTS. A small stimulus at the PRL generated more extensive cortical activation than at a non-PRL location, but neither yielded activation in the foveal cortical projection. Both passive and active viewing of full-field stimuli left a silent zone at the posterior pole of the occipital cortex, implying a lack of complete cortical reorganization. The silent zone was smaller in the task requiring active viewing compared with the task requiring passive viewing, especially in JMD subjects. CONCLUSIONS. The PRL for MD subjects has more extensive cortical representation than a retinal region with matched eccentricity. There is evidence for incomplete functional reorganization of early visual cortex in both JMD and AMD. Functional reorganization is more prominent in JMD. Feedback signals, possibly associated with attention, play an important. © Association for Research in Vision and Ophthalmology.
Persistent Identifierhttp://hdl.handle.net/10722/132212
ISSN
2015 Impact Factor: 3.427
2015 SCImago Journal Rankings: 2.008
PubMed Central ID
ISI Accession Number ID
Funding AgencyGrant Number
National Institutes of HealthR01 EY002934
RO1EB002009
Funding Information:

Supported by National Institutes of Health Grants R01 EY002934 and RO1EB002009.

References

 

DC FieldValueLanguage
dc.contributor.authorLiu, Ten_HK
dc.contributor.authorCheung, SHen_HK
dc.contributor.authorSchuchard, RAen_HK
dc.contributor.authorGlielmi, CBen_HK
dc.contributor.authorHu, Xen_HK
dc.contributor.authorHe, Sen_HK
dc.contributor.authorLegge, GEen_HK
dc.date.accessioned2011-03-21T09:02:06Z-
dc.date.available2011-03-21T09:02:06Z-
dc.date.issued2010en_HK
dc.identifier.citationInvestigative Ophthalmology And Visual Science, 2010, v. 51 n. 12, p. 6826-6834en_HK
dc.identifier.issn0146-0404en_HK
dc.identifier.urihttp://hdl.handle.net/10722/132212-
dc.description.abstractPURPOSE. Activity in regions of the visual cortex corresponding to central scotomas in subjects with macular degeneration (MD) is considered evidence for functional reorganization in the brain. Three unresolved issues related to cortical activity in subjects with MD were addressed: Is the cortical response to stimuli presented to the preferred retinal locus (PRL) different from other retinal loci at the same eccentricity? What effect does the role of age of onset and etiology of MD have on cortical responses? How do functional responses in an MD subject's visual cortex vary for task and stimulus conditions? METHODS. Eight MD subjects-four with age-related onset (AMD) and four with juvenile onset (JMD)-and two agematched normal vision controls, participated in three testing conditions while undergoing functional magnetic resonance imaging (fMRI). First, subjects viewed a small stimulus presented at the PRL compared with a non-PRL control location to investigate the role of the PRL. Second, they viewed a full-field flickering checkerboard compared with a small stimulus in the original fovea to investigate brain activation with passive viewing. Third, they performed a one-back task with scene images to investigate brain activation with active viewing. RESULTS. A small stimulus at the PRL generated more extensive cortical activation than at a non-PRL location, but neither yielded activation in the foveal cortical projection. Both passive and active viewing of full-field stimuli left a silent zone at the posterior pole of the occipital cortex, implying a lack of complete cortical reorganization. The silent zone was smaller in the task requiring active viewing compared with the task requiring passive viewing, especially in JMD subjects. CONCLUSIONS. The PRL for MD subjects has more extensive cortical representation than a retinal region with matched eccentricity. There is evidence for incomplete functional reorganization of early visual cortex in both JMD and AMD. Functional reorganization is more prominent in JMD. Feedback signals, possibly associated with attention, play an important. © Association for Research in Vision and Ophthalmology.en_HK
dc.languageengen_US
dc.publisherAssociation for Research in Vision and Ophthalmology. The Journal's web site is located at http://www.iovs.orgen_HK
dc.relation.ispartofInvestigative Ophthalmology and Visual Scienceen_HK
dc.subject.meshCorneal Dystrophies, Hereditary - physiopathology-
dc.subject.meshMacular Degeneration - physiopathology-
dc.subject.meshRetina - physiopathology-
dc.subject.meshVisual Cortex - physiopathology-
dc.subject.meshVisual Perception - physiology-
dc.titleIncomplete cortical reorganization in macular degenerationen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0146-0404&volume=51&issue=12&spage=6826&epage=6834&date=2010&atitle=Incomplete+cortical+reorganization+in+macular+degeneration-
dc.identifier.emailCheung, SH:singhang@hku.hken_HK
dc.identifier.authorityCheung, SH=rp00590en_HK
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1167/iovs.09-4926en_HK
dc.identifier.pmid20631240-
dc.identifier.pmcidPMC3055781-
dc.identifier.scopuseid_2-s2.0-79955481767en_HK
dc.identifier.hkuros179156en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-79955481767&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume51en_HK
dc.identifier.issue12en_HK
dc.identifier.spage6826en_HK
dc.identifier.epage6834en_HK
dc.identifier.eissn1552-5783-
dc.identifier.isiWOS:000284837500095-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridLiu, T=9273613400en_HK
dc.identifier.scopusauthoridCheung, SH=7202473508en_HK
dc.identifier.scopusauthoridSchuchard, RA=6603863868en_HK
dc.identifier.scopusauthoridGlielmi, CB=25629436700en_HK
dc.identifier.scopusauthoridHu, X=34770364200en_HK
dc.identifier.scopusauthoridHe, S=7402691306en_HK
dc.identifier.scopusauthoridLegge, GE=7005064208en_HK
dc.identifier.citeulike7562634-

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