Figure 1.

In vivo electrophysiological recording and classification of single units. A, Illustration of the representative placement of electrode array in the SNr. B, Placement of the 4 × 4 electrode array as shown in representative coronal brain sections from three different mice. Red arrows indicate electrode tracks. Scale bar, 500 μm. C, Summary of electrode placements. The coronal sections are from the Allen Mouse Brain Atlas (Lein et al., 2007); http://mouse.brain-map.org/. D, Four representative examples of putative GABAergic neurons, showing the waveforms and interspike interval distribution. E, Plot of firing rate versus spike width. Neurons with wider action potentials are excluded (other).