Extended Data Fig. 6: Driving local circuits: opsin expression and power dependence.
From: Neuropixels Opto: combining high-resolution electrophysiology and optogenetics
a. Horizontal section through the cleared brain of mouse 2 (Fig. 4), showing fluorescence of ChrimsonR-tdTomato (red), which was targeted at inhibitory neurons via a DLX2.0 enhancer, and of GCaMP (green), which was targeted at excitatory neurons via a CaMK2a driver. b-c, Magnified regions in a demonstrate that tdTomato and GCAMP express in distinct neural populations. d. Coronal slice of the red channel showing fluorescence of ChrimsonR-tdTomato and of the fluorescent dye DiI (dashed), which was used to track probe trajectories. The two probe tracks traverse visual and retrosplenial cortex. e. Number of units modulated by light (same criteria as in Fig. 4) as a function of power of light emitted from the probe. Data in this panel and following panels are from a single session in mouse 3. f. Number of sites activating each unit at each level of light power. g. Modulation index as a function of laser power. All units that are eventually modulated at any power are included in the plot. h. Mean PSTH of activated units as a function of laser power. i. Same, for inactivated units.
