2. ELECTROPHYSIOLOGY OF THE RETINA
41
The response type of a given unit is not always fixed but can change
under certain conditions as described below.
B. Receptive Field
The ganglion cell responds only when light falls within a certain
circumscribed area of the retina. This area is termed, according to Hartline ( 1938), the “receptive field” of the ganglion cell. Mapping with a
small spot of white light, several types of organization of the receptive
field are discerned which are characteristic to individual ganglion cells.
The two simple types are everywhere on and everywhere off type, but
more common are those which are apparently made up of the combination of these two simple types. Figure 5 illustrates an off center-on
periphery type obtained in the goldfish (Wagner et al., 1960). This is
identical with one of the two typical types first observed in the cat by
Kuffler (1953). The reverse type, that is, the on center-off periphery
type, is also frequently encountered in the fish.
Some ganglion cells in the fish are color coded, responding differently
to different wavelengths of light (Wagner et al., 1960; Motokawa et al.,
1960). The unit shown in Fig. 6 responds with an on discharge to green
but with off discharge to red. Units of the reverse relation (red on0
0
0 0
0
- ..
X = O F F
0
0
0
0
0 =ON
0 =ON-OFF
I
I M M
I
Fig. 5. Receptive field of a single goldfish ganglion cell. Solid black area
indicates region where only off responses were found. Hatched area indicates region
where on-off type responses were found. On responses were found only in the
periphery of on-off area. Test stimulus, 153,~ in diameter; wavelength, 600 mp;
and intensity, 18.0 pW/cmz. From Wagner et al. (1960).
41
The response type of a given unit is not always fixed but can change
under certain conditions as described below.
B. Receptive Field
The ganglion cell responds only when light falls within a certain
circumscribed area of the retina. This area is termed, according to Hartline ( 1938), the “receptive field” of the ganglion cell. Mapping with a
small spot of white light, several types of organization of the receptive
field are discerned which are characteristic to individual ganglion cells.
The two simple types are everywhere on and everywhere off type, but
more common are those which are apparently made up of the combination of these two simple types. Figure 5 illustrates an off center-on
periphery type obtained in the goldfish (Wagner et al., 1960). This is
identical with one of the two typical types first observed in the cat by
Kuffler (1953). The reverse type, that is, the on center-off periphery
type, is also frequently encountered in the fish.
Some ganglion cells in the fish are color coded, responding differently
to different wavelengths of light (Wagner et al., 1960; Motokawa et al.,
1960). The unit shown in Fig. 6 responds with an on discharge to green
but with off discharge to red. Units of the reverse relation (red on0
0
0 0
0
- ..
X = O F F
0
0
0
0
0 =ON
0 =ON-OFF
I
I M M
I
Fig. 5. Receptive field of a single goldfish ganglion cell. Solid black area
indicates region where only off responses were found. Hatched area indicates region
where on-off type responses were found. On responses were found only in the
periphery of on-off area. Test stimulus, 153,~ in diameter; wavelength, 600 mp;
and intensity, 18.0 pW/cmz. From Wagner et al. (1960).