Journal of Neurophysiology, Vol 40, Issue 1 119-135, Copyright © 1977 by APS
Simple striate neurons in the cat. I. Comparison of responses to moving and stationary stimuli
R. C. Emerson and G. L. Gerstein
1. Peristimulus time (PST) histograms of simple striate responses to static
presentations of narrow bright and dark bars in an array of receptive-field
(RF) positions have demonstrated one to four response regions with distinct
response properties. 2. There is a high degree of correlation of these
responses with PST histograms of responses to the same stimuli moving
smoothly ("dynamic" stimuli) in a direction perpendicular to the long axis
of the RF. 3. Trailing responses to smoothly moving bar stimuli usually
occur as the stimulus leaves an apparently inhibitory (for that stimulus)
RF region. 4. Spatially leading responses to smoothly moving stimuli occur
just as a bar stimulus enters an excitatory RF region, and may be based on
certain gradient-detecting properties of neurons. 5. Close agreement in
peak firing rates and in positions of responses for statically and
dynamically elicited responses in units that are not strongly directionally
selective suggests the possibility that in most respects smooth movement
responses may be the sequential linear superposition of static responses. A
quantitative superposition of static responses from two units supports this
conclusion. 6. The dependence on a steady background for sustained
responses to static presentation of dark bars illustrates the significance
of steady illumination in the RF and raises questions about the efficacy of
using edge stimuli as elemental visual probes.
