The correlation between cholinergic sensitivity and the level of
stratification for ganglion cells was examined in the rabbit retina. As
examples, we have used ON or OFF α ganglion cells and ON/OFF
directionally selective (DS) ganglion cells. Nicotine, a cholinergic
agonist, depolarized ON/OFF DS ganglion cells and greatly enhanced
their firing rates but it had modest excitatory effects on ON or OFF α
ganglion cells. As previously reported, we conclude that DS ganglion cells
are the most sensitive to cholinergic drugs. Confocal imaging showed that
ON/OFF DS ganglion cells ramify precisely at the level of the
cholinergic amacrine cell dendrites, and co-fasciculate with the
cholinergic matrix of starburst amacrine cells. However, neither ON or OFF
α ganglion cells have more than a chance association with the
cholinergic matrix. Z-axis reconstruction showed that OFF α
ganglion cells stratify just below the cholinergic band in sublamina
a while ON α ganglion cells stratify just below cholinergic
b. The latter is at the same level as the terminals of calbindin
bipolar cells. Thus, the calbindin bipolar cell appears to be a prime
candidate to provide the bipolar cell input to ON α ganglion cells in
the rabbit retina. We conclude that the precise level of stratification is
correlated with the strength of cholinergic input. Alpha ganglion cells
receive a weak cholinergic input and they are narrowly stratified just
below the cholinergic bands.