Supplementary Figure 9: Recordings from Purkinje cells using Neuropixels probes.

a. Histological localization of the Neuropixels recording track in a coronal section of cerebellum (6.2 mm caudal from bregma). Blue: Neurotrace, Red: DiI (highlighting the electrode track). Dashed red line shows the projection of the electrode track onto this anatomical section. b. Examples of complex spikes (CSs) and simple spikes (SSs) recorded using Neuropixels probes. Each panel shows 100 overlaid raw traces (with mean and s.d. shown as black line and shaded area, respectively) on adjacent recording sites (20 µm vertical and horizontal separation), situated from -1890 µm to -1990 µm below the surface of the brain shown in panel a. Red: CS recordings showing channels located in the molecular (top channels) and Purkinje (middle channels) layers of the cerebellar cortex. Blue: corresponding SS recordings from the same putative Purkinje cells exhibiting post-CS pauses, as in Fig. 4c (SS1 and SS2 associated with CS1 and CS2, respectively). c. Example raw traces (gray) recorded on three adjacent vertically consecutive channels (20 µm separation) of a Neuropixels probe within the Purkinje cell layer. The spikes of the simple spike cluster (black) and complex spike cluster (red) shown in Fig. 4a–c are highlighted. Note that several other simple and complex spike clusters were identified within this Purkinje cell layer but are not highlighted for clarity.