Fig. 1.

Cholinergic and noncholinergic medial septum/diagonal band of Broca (MS/DB) neurons display different rates of spontaneous firing. A: coronal brain slice (200 μm) from a postnatal day 13 C57Bl/6 mouse with MS/DB outlined. B: a magnified view of the recording setup with a patch recording pipette (right) on the neuron being recorded and a multibarrel pipette assembly (left) used to deliver drugs positioned ∼10 μm from the cell. C: example of an MS/DB neuron filled with Lucifer yellow during recording (C1) displaying a slow firing rate (C2). D: example of an MS/DB neuron filled with Lucifer yellow during recording (D1) displaying a fast firing rate (D2). Scale bars apply to both C and D: vertical = 20 mV; horizontal = 1 s. E–G: the slice was fixed after electrophysiological recording and processed immunohistochemically with an antibody against choline acetyltransferase (ChAT). The cells illustrated in C and D were recovered and are denoted (→, *) in E and F, respectively. The overlay in F indicates that the slow-firing cell illustrated in C, but not the fast-firing cell illustrated in D, is ChAT immunopositive.