Narrow-band 1, 2, 3, 4, 8, 16, 24, 32, 48, 64, and 96 cycles/360 degrees angular frequency filters.
We measured human frequency response functions for eleven angular frequency filters using a forced-choice procedure in a supra-threshold summation paradigm. Each of the eleven functions of 17 experimental conditions was measured 4-9 times among 12 observers. Results show that, for the arbitrarily selected filter phases, maximum summation effect occurred at test frequency for all filters. These results lead to the conclusion that there are narrow-band angular frequency filters operating in human visual system mostly through summation surrounded by inhibition at the specific test frequency ranges. Our previous suggestion (Simas and Santos, 2002), arguing that summation for the higher angular frequency filters should occur if background angular frequency contrast were set to a maximum of 5 times the test frequency threshold, was supported.
Simas
Maria Lúcia De Bustamante
ML
LabVis-UFPE, Departamento de Psicologia, Universidade Federal de Pernambuco, Rua Acadêmico Hélio Ramos s/n, 9 Andar, Recife 50670-901, PE, Brazil. maria.simas@uol.com.br
Dos Santos
Natanael Antonio
NA
D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000502:physiology; D009903:Optical Illusions / Q000502:physiology; D009949:Orientation / Q000502:physiology; D011601:Psychophysics; D012160:Retina / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology