Abstract
It has been assumed that the visual system of primates has about eight spatial-frequency channels, covering a range from 0.25 to 30 cycles/deg, with a step of one octave. New electrophysiological studies of parvo and magno pathways with various tonic and phasic properties have made it possible to modernize the psychophysical models of the multichannel, spatial-frequency organization of the visual system. It is established that, in the primary visual cortex, some neurons obtain signals with outputs of only the magno system, others from only the parvo system, and a third group from both systems. The channels formed by these cells not only have specific spatial-frequency characteristics but also possess phasic and tonic (temporal) properties that can appear for definite stimulation conditions. Under threshold stimulation conditions, neurons of three temporal broad-band channels are activated: tonic (low-frequency), phasic (first band-pass filter), and tuned only to the flickers of a second band-pass filter, with maximum sensitivities of 1, 5, and 10 Hz, respectively. For a subthreshold stimulus between 1 and 5 Hz, additional channels are switched on and obtain combined magno and parvo inputs. Four chromatic threshold tonic channels are revealed: red, yellow, green, and blue. Certain chromatic stimuli are conducted fairly quickly in a separate chromatic shape channel.
| Original language | English |
|---|---|
| Pages (from-to) | 797-808 |
| Number of pages | 11 |
| Journal | Journal of Optical Technology (A Translation of Opticheskii Zhurnal) |
| Volume | 66 |
| Issue number | 9 |
| Publication status | Published - Sept 1999 |