Bipolar cells in the retina of the tiger salamander were studied by intracellular recording. Their receptive fields consisted of a central region and a surround which, when stimulated, antagonized the response of the center. The spatial distributions of the center and surround components were determined, using drugs that selectively eliminated the surround. The receptive field is shown to be a linear combination of the two components. Because of the spatial antagonism the receptive field acts as a bandpass spatial filter. The importance of this filtering in photon detection is discussed.>

Interaction between nerve cells, mediated by electrical coupling, is a common feature of the nervous system. When such electrical interactions occur within an entire population of similar neurons, the dynamic behavior of each individual cell is influenced by the properties of the whole network. It is shown that when the membrane impedance of such cells can be linearized to a satisfactory approximation and the zeros and poles of the linearized impedance are known, analytical solutions to the network equations can be found that describe the dynamics of the responses of any given cell to one-dimensional and two-dimensional stimuli. This analysis applied to the network of photoreceptors and horizontal cells in the vertebrate retina may be helpful in understanding the initial stages in the processing of visual information.