Although gross recordings of the ganzfeld flash-evoked electroretinogram (ERG) can potentially provide information about the
activity of many, if not all, retinal cell types, it is necessary to dissect the ERG into its components to realize this potential
fully. Here we describe various procedures that have been used in intact mammalian eyes to identify and characterize the contributions
to the dark-adapted ERG of different cells in the retinal rod pathway. These include (1) examination of the very early part
of the response to a flash (believed to reflect directly the photocurrent of rods), (2) application of high-energy probe flashes
to provide information about the underlying rod photoreceptor response even when this component is obscured by the responses
of other cells, (3) pharmacological suppression of responses of amacrine and ganglion cells to identify the contribution of
these cells and to reveal the weaker responses of bipolar cells, (4) use of pharmacological agents that block transmission
of signals from rods to more proximal neurons to separate responses of rods from those of later neurons, (5) examination of
the ERG changes produced by ganglion-cell degeneration or pharmacological block of nerve-spike generation to identify the
contribution of spiking neurons, (6) modeling measured amplitude-energy functions and timecourse of flash responses and (7)
using steady backgrounds to obtain differential reductions in sensitivity of different cell types. While some of these procedures
can be applied to humans, the results described here have all been obtained in studies of the ERG of anaesthetized cats, or
macaque monkeys whose retinas are very similar to those of humans.
A-wave - B-wave - electroretinogram - retina - STR
This revised version was published online in July 2006 with corrections to the Cover Date.