A sensory mechanism for amblyopia: electrophysiological studies.
Steady-state visual evoked potentials were elicited by the appearance/disappearance of sinusoidal gratings of varying spatial frequency for both eyes of amblyopic subjects at temporal frequences from 2--32 Hz. The amblyopic eyes showed reduced responses relative to those of the nonamblyopic eyes across a wide range of spatial frequencies, the difference between the 2 eyes being most marked for high spatial frequencies and low temporal frequencies. Both the nonamblyopic and the amblyopic eyes showed a linear relation between the evoked potential amplitude and the logarithm of the stimulus contrast; however, the slope of the line was flatter for the amblyopic eyes. Possible neural mechanisms for the amblyopic eyes' reduced responses to spatial contrast are considered.
D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D002415:Cats; D005071:Evoked Potentials; D005260:Female; D005583:Fourier Analysis; D000882:Haplorhini; D006801:Humans; D008297:Male; D008959:Models, Neurological; D010775:Photic Stimulation; D014792:Visual Acuity; D014795:Visual Pathways / Q000503:physiopathology*