MacNlCHOL, WOLBARSHT, AND WAGNER 801 



Fig. 3. Intraretinal recording from goldfish. Chromatic (C) type response to 

 a linear change in wavelength as a function of time from 400 to 750 m/^. The 

 time required for this change was 0.75 seconds. The two traces are simultaneous 

 high- and low-gain records of the same response, d-c recording was used on both 

 channels. The upper straight line represents mv, and the lower 100 mv, for the 

 low-gain channel. The peak to peak amplitude of the high-gain response was 

 approximately 9 millivolts. The intensity of the stimulus at 600 m^ was 30 

 ^watts/cm-. The stimulus was not equal energy. See Wagner, MacNichol, and 

 \Volbarsht (32) for energies at other wavelengths and other details concerning 

 the technique by which this record was made. In this and subsequent records, 

 except where otherwise indicated, the stimulus was circular in outline and 5 mm 

 in diameter, centered over the electrode. 



have not been able to obtain "C" or "L" responses from the goldfish 

 which were sufficiently stable and long-lasting for quantitative studies. 



An investigation was then made of the discharges of the retinal 

 ganglion cells. Since micropipettes are not suitable for this purpose, 

 small, insulated metal microelectrodes were used instead. Stable, long- 

 lasting responses were obtained, making it possible to study them in 

 considerable detail. 



As shown in Fig. 4, most of the units when stimulated with light 

 gave an "on-off" type of discharge pattern, that is, they gave a short 

 burst of impulses when the light was turned on and a brief burst when 

 the light was turned off. This "on-off" pattern is similar to that found 



