Perceptual visual filling-in of toxoplasmic retinochoroiditis scotomas.
Perceptual visual filling-in of toxoplasmic retinochoroiditis chronic scotomas was studied in 13 patients. Although there is deficit of visual inputs, patients with such chronic lesions perceive the region in the visual field uninterrupted. Targets were programmed to appear just outside the edge of the retinal lesion, and healthy retinal areas in the same eye. The results showed no significant difference in perceptual filling-in latencies (P>0.05).


CONCLUSIONS
(i) neural mechanisms of filling-in at the blind spot are probably involved explaining this perceptual phenomenon; (ii) any neuronal changes occurring at the edge of the lesion only affected filling-in within the scotoma area.
Alvarenga
Denise P
DP
Neuroscience and Behavior Laboratory, Institute of Biology, Brasília University, Brasilia, Brazil. oftalmop@terra.com.br
Couto
Marcia F
MF
Pessoa
Valdir F
VF
D000222:Adaptation, Physiological / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002825:Chorioretinitis / Q000175:diagnosis / Q000469:parasitology / Q000503:physiopathology*; D002829:Choroid / Q000469:parasitology / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007088:Illusions / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012160:Retina / Q000469:parasitology / Q000473:pathology / Q000503:physiopathology; D012607:Scotoma / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D014122:Toxoplasma; D014126:Toxoplasmosis, Ocular / Q000175:diagnosis / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*