Do retinal ganglion cells act as independent encoders?
Correlated firing among neurons is a widespread phenomenon in the
visual system. Neighboring neurons, in areas from retina to cortex,
tend to fire together more often than would be expected by chance. The
role of this correlated firing in encoding visual information is
unclear and controversial. Here we examined its role in the retina. We
presented the retina with natural stimuli and recorded the responses
of its output cells, the ganglion cells. We then used a novel approach
to measure the amount of information about the stimuli that could be
obtained from the cells under two conditions: 1) when their correlated
firing was taken into account, and 2) when their correlated firing was
ignored. We found that greater than 90% of the information about the
stimuli could be obtained from the cells when their correlated firing
was ignored. This indicates that the ganglion cells act largely
independently to encode information, which greatly simplifies the
problem of decoding their activity.