Spike characteristics of cholinergic neurons in ChAT-Cre/Ai32(ChR2-YFP) and ChAT-Cre/Ai35(Arch-GFP) mice.

<p><b>(A)</b> Whole-cell recordings from a ChR2-YFP-labeled neuron in nucleus basalis in an acute slice, illustrating the spiking pattern (upper panel) and after-spike potentials (lower panel) when spikes were evoked by somatic current injections (upper panel 300 ms, 50 pA; lower panel 1 ms, 500 pA current). Dashed horizontal lines denote 0 mV. Resting membrane potentials were -50 mV and -51 mV for upper and lower recordings, respectively. <b>(B)</b> Mean ± SEM spiking frequency as a function of current injected at the somata of 10 cholinergic neurons from ChAT-Cre/Ai32(ChR2-YFP) mice. Grey line: mean spike rates for cholinergic neurons from wild-type mice, from Hedrick & Waters (2010). <b>(C)</b> Whole-cell recordings from an Arch-GFP-labeled neuron in nucleus basalis in an acute slice, illustrating the spiking pattern (upper panel) and after-spike potentials (lower panel) when spikes were evoked by somatic current injections (upper panel 300 ms, 150 pA; lower panel 1 ms, 2000 pA current). Dashed horizontal lines denote 0 mV. Resting membrane potentials were -53 mV and -52 mV for upper and lower recordings, respectively. <b>(D)</b> Mean ± SEM spiking frequency as a function of current injected at the somata of 9 cholinergic neurons from ChAT-Cre/Ai35(Arch-GFP) mice. Grey line: mean spike rates for cholinergic neurons from wild-type mice, from Hedrick & Waters (2010).</p

Basal forebrain cell counts.

<p>Basal forebrain cell counts.</p

Membrane properties of cholinergic neurons.

<p>Membrane properties of cholinergic neurons.</p

Cholinergic cell densities in basal forebrain.

<p>Cell densities of ChAT-positive neurons in basal forebrain from ChAT-Cre, ChAT-Cre/Ai32(ChR2-YFP), ChAT-Cre/Ai35(Arch-GFP) and C57BL/6J (WT) mice. Each bar represents mean ± SEM cell density from 3 mice.</p

Hyperpolarization of cholinergic neurons from ChAT-Cre/Ai35(Arch-GFP) mice.

<p><b>(A)</b> Whole-cell recordings from Arch-GFP-labeled neurons in nucleus basalis in acute slices from Arch-ChR2 mice, illustrating the effects of 300 ms white illumination (bar) at intensities of 1.2, 1.7, 2.2 and 3.7 mW/mm². Dashed horizontal lines denote 0 mV. Resting membrane potentials -51, -51, -52 and -52 mV. <b>(B)</b> Steady-state hyperpolarization and membrane time constant during white illumination from the recording illustrated in panel A. Arrowheads indicate example traces in panel A. <b>(C and D)</b> Inhibition of spiking by white illumination. Spiking was evoked by DC (C) or 2Hz (D) current injection to depolarize cell beyond spike threshold. Spikes were eliminated by 7 mW/mm² white illumination (bar) for 1 second (C) or for 20 ms (D). Initial membrane potential (during DC current injection) was -33 mV in panel C and resting membrane potential was -49 mV in panel D.</p

Behavioral artifact of deep brain illumination.

<p>(A) Schematic illustration of the implanted guide cannula, fiber and deep brain illumination. Drawn approximately to scale. (B) Schematic illustration of the fiber implant (red circle) viewed from the dorsal surface of the head, illustrating the position of the fiber relative to the eyes. (C) Mean running speed trajectory for a single session in which 50% of trials included 640 nm illumination. Rewarded and unrewarded objects were presented at 100% contrast with (red traces) and without (black traces) 640 nm illumination. (D) Summary of performance during the session illustrated in panel B. Trials with and without 640 nm illumination are illustrated with red and black vertical bars, respectively. (E) Stop probabilities for the session illustrated in panel C. (F) Psychometric curves for a single wild-type mouse across four sessions, with different deep brain illumination in each session: no deep brain illumination (left panel), 10 mW of 473 nm illumination (center left), 10 mW of 589 nm illumination (center right), 10 mW of 640 nm illumination (right). Each session included trials with (colored symbols and lines) and without (black, grey) illumination. Stop probabilities for rewarded and unrewarded trials are illustrated with darker and lighter colors, respectively. (G) Stop probabilities for zero-contrast objects (false alarm rates) for 1, 3 and 10 mW at 473 (blue), 589 (yellow) and 640 nm (red) illumination. Results for each intensity and wavelength were collected in a different session and compared to the stop probability without illumination in the same session (in black). Asterisks denote significant effects of illumination (p < 0.01). Numbers of mice: 6, 8 and 8 mice for 1, 3 and 10 mW of 473 nm illumination; 6, 5 and 6 mice for 1, 3 and 10 mW of 589 nm illumination; 4, 5 and 5 mice for 1, 3 and 10 mW of 640 nm illumination. (H) Reward rate under illuminated and control conditions, within the same session. Results from individual mice are illustrated in grey, mean ± SEM of 5 mice in black. Rewards summed across rewarded and unrewarded objects of all contrasts; numbers of trials of each contrast with and without illumination were approximately equal.</p

Performance across a range of contrasts.

<p>(A) Mean running speed trajectories, for a single session, for objects of contrasts from 0 to 100%, rewarded (upper row) and unrewarded (lower row) objects. Dashed vertical lines: limits of reward window. (B) Psychometric curves for rewarded (vertical) and unrewarded (horizontal) objects for the session illustrated in panel A. Line, fit to Weibull distribution; error bars, 95% confidence intervals. (C) Discriminability of rewarded and unrewarded objects as a function of contrast. Each point is the mean (± SEM) from 6 mice.</p

Measurement of light exiting the left eye.

<p>(A) Schematic illustrating the experimental arrangement during measurement of light emitted through the left eye. Light (red arrow) propagated from the implanted fiber (red circle) to a spectroradiometer, placed in front of the left eye. (B) Intensities measured by the spectroradiometer during 10 mW illumination through the implanted fiber at 473, 589 and 640 nm. 3 mice.</p

Light adaptation of left and right retinae.

<p>(A) Schematic illustrating the experimental arrangement of mouse head, visual stimulus monitor and LED, the latter placed to illuminate the left retina. (B) Example ERG recordings from left and right eyes of a mouse under different ambient illumination conditions: monitor and LED off (dark-adapted; top row); monitor on and LED off (middle row), and monitor and LED both on (lower row). Optogenetic stimulus was 200 ms, 10 mW, 640 nm illumination (grey). (C) Summary of the effects of LED illumination on the peak amplitude of the ERG voltage in different adaptation states. Left point (dark-adapted) with monitor and LED off. Remaining points were acquired with the monitor on and the LED providing differing illumination intensities. Points represent mean ± SEM (3 mice). Arrowhead marks 0.14 Wsr^-1m^-2.</p

Performance of a visual discrimination task.

<p>(A) Schematic illustration of visual discrimination task. The mouse is head-restrained, on a running disk. Visual objects, displayed on a monitor, travel along the horizon from left to right. (B) Schematic illustration of the relative positions of mouse and monitor. (C) Running speed as a function of distance run by the mouse in two example trials. The position of the monitor, object and reward window are drawn to scale on the distance axis. (D) Summary of performance during a single example session, plot over time from the start to the end of the session (from left to right). Vertical lines indicate trials, sorted into four categories by object (rewarded vs unrewarded) and behavioral response (detected and undetected objects). The mouse collected rewards only on trials in which it indicated detection of a rewarded object (uppermost category). (E) Mouse-to-mouse and session-to-session variability in stop probability for rewarded and unrewarded objects and in discriminability (d'). Results are for 6 mice (rows) and across 6 sessions (columns).</p