Expansion of visual receptive fields in experimental glaucoma.
Glaucoma is a major cause of blindness and is characterized by death of retinal ganglion cells. In a rat model of glaucoma in which intraocular pressure is raised by cautery of episcleral veins, the somata and dendritic arbors of surviving retinal ganglion cells expand. To assess physiological consequences of this change, we have measured visual receptive-field size in a primary retinal target, the superior colliculus. Using multiunit recording, receptive-field sizes were measured for glaucomatous eyes and compared to both those measured for contralateral control eyes and to homolateral eyes of unoperated animals. Episcleral vein occlusion increased intraocular pressure. This was accompanied by a significant increase in receptive-field size across the superior colliculus. The expansion of receptive fields was proportional to both degree and duration of the increase of intraocular pressure. We suggest that this increase in the size of receptive fields of glaucomatous eyes may be related to the increase in the size of dendritic arbors of the surviving ganglion cells in retina.
King
Wayne Michael
WM
Departments of Ophthalmology and Cell Biology and Anatomy, New York Medical College, Valhalla, New York 10595, USA.
Sarup
Vimal
V
Sauvé
Yves
Y
Moreland
Colleen M
CM
Carpenter
David O
DO
Sharma
S C
SC
D000818:Animals; D004195:Disease Models, Animal; D004596:Electroretinography / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005901:Glaucoma / Q000150:complications / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D007429:Intraocular Pressure / Q000502:physiology*; D016014:Linear Models; D010775:Photic Stimulation / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012162:Retinal Degeneration / Q000209:etiology; D012170:Retinal Vein Occlusion / Q000150:complications; D013477:Superior Colliculi / Q000473:pathology; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000473:pathology / Q000503:physiopathology