Excitatory and Inhibitory Processes Giving Rise to the Delayed Response in the Retinal Ganglion Cell of Frog

Abstract

The response of the ganglion cells in the frog’s retina to visual stimuli has been extensively studied during the last four decades. The pioneering work has been done by Hartline (1938, 1940), Barlow (1953, 1957) and by Maturana et al. (1960). Most of the properties of the ganglion cell response can be described satisfactorily on the basis of lateral interactions within the receptive field (RF) of the cell (see rewievs e.g. by Varjú, 1969 and more recently by Grüsser and Grüsser, 1976). One particular response described first by Pickering and Varjú (1967) and termed ‘delayed response’ is less well understood. This response is elicited mainly by short light flashes projected on to the entire RF or parts of it. The basic properties of the response are illustrated in fig. 1; the results presented there have all been obtained by homogeneously illuminating the entire RF of the cells with flashes of 50 μs halfwidth and of varying intensity I. Two other parameters, the intensity B of an homogeneous background illumination and the dark adaptation time t_d which elapsed after turning off the room lights have also been varied.