Figure 2.

Basal type I and type II neurons located side by side in vitro differed in their endogenous firing features. Lucifer yellow was included in the internal solution for one of the recordings to identify unequivocally the neuron from which the recording was made. A-D, Images of the same field in vitro are shown for different combinations of illumination and filter settings. A, Incandescent illumination with Hoffman optics shows the general shape of the neurons on a background of satellite cells. The two neurons from which recordings were made are labeled 1 and 2. B, Fluorescent image of the Lucifer yellow-filled neuron (green), labeled 2. C, Fluorescent image showing that polyclonal peripherin antibody (red) is enriched in the neuron labeled 2 and is essentially absent from the neuron labeled 1. D, Combination of images shown in A and C to show the location of the peripherin-positive neuron. E, Current-clamp recording from neuron 1 shows firing features typical of a type I basal spiral ganglion neuron. F, Current-clamp recordings from neuron 2. Calibration bar applies to E and F. G, Current-voltage relationships are shown for the type I (black) and type II (red) neurons. Measurements were made at the end of the 240 msec step depolarization (diamonds) for both depolarizing and hyperpolarizing constant-current injections. The peak voltages achieved in response to hyperpolarizing constant-current injections were denoted with triangles.