Case report: responses to stripe width changes and to complex gratings of a patient with pattern-sensitive epilepsy.
A pattern-sensitive subject's ability to see faint gratings of several different stripe widths (spatial frequencies) was essentially normal, with the greatest sensitivity occurring for gratings with 2 cycles of light and dark stripes per degree of visual arc (c/deg). Epileptiform discharges, however, occurred maximally at a narrower stripe width, 5 c/deg. The 50% bandwidth of the epileptic response was approximately one octave, which is similar to postulated 'spatial frequency channels' in the visual system. Hypothesized inhibitory interactions between the 5 c/deg grating and a 15 c/deg grating were not observed.
D000328:Adult; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000523:psychology; D004827:Epilepsy / Q000523:psychology*; D004832:Epilepsy, Absence / Q000523:psychology; D005071:Evoked Potentials; D005556:Form Perception; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D012684:Sensory Thresholds