Surround control of center adaptation in the receptive fields of frog retinal ganglion cells.

The sensitivity and intensity-response [R(log I)] functions of the receptive field center were determined by extracellular recording from frog retinal ganglion cells. The object was to study the steady-state adapting effects of peripheral background patterns: steady annuli and spinning "windmills" of light. Steady annular backgrounds could not be shown to directly effect any change of center responsiveness, only an enhancement of late response components attributable to depression of surround sensitivity. Movement of a windmill pattern shifted R(log I) functions to higher log intensities and decreased the maximal number of spikes in the response, but did not depress the saturation level of the impulse frequency. Its action thus resembled direct light-adaptation of the center.