The Neural
Control of Vision
G. The Function of the On and Off Channels in Vision
To
test the ability of monkeys to detect stimuli made visible by virtue of
light increment or decrement monkeys were trained to make saccadic eye
movements after central fixation, to either a light or a dark spot as
depicted on the monitors shown in Figure 26.
Under normal condition monkeys do this very well and quite quickly as
shown by the saccadic reaction times. After APB blocks the ON cells in
the retina, monkeys have difficulty seeing the bright spot and when they
do, it takes them a long time to respond. They continue seeing the dark
spot unabated.
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