Figure 1.

Performance in a Visually Guided Virtual Reality Navigation Task Is Motor Cortex Dependent

(A) Mice were trained to control movement in a virtual environment through locomotion on the spherical treadmill. Upon reaching the target at the end of the corridor, mice received a water reward. A blue laser was directed at left and right motor cortex in rapid alternation for optogenetic inhibition of neuronal activity via excitation of vGAT+ interneurons.

(B) Top: schematic of the tunnel with three example traversals at the beginning of training (day 1, tunnel is not drawn to scale, length-to-width ratio: 5:1). Bottom: schematic of the tunnel with three example traversals from an expert mouse (day 8). With increasing performance of the mice, we increased the length of the tunnel to increase the difficulty of the task (length-to-width ratio: 30:1).

(C) Average performance as a function of training days (fraction of time spent running in the direction of the target, see STAR Methods) in mice with (blue, n = 12 mice) and without (black, n = 22 mice) motor cortex inhibition. Here, data from all three groups of mice with different inhibition laser power levels (1 mW, 2 mW, and 10 mW) are pooled (see also Figure S1E). Error bars indicate SEM over mice. Dashed black line marks chance performance. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 10⁻³; Wilcoxon rank sum test. Mice trained with photoinhibition did not significantly improve performance as opposed to the control group (day 1 versus day 8; with photoinhibition: p = 0.17, n = 12 mice; without photoinhibition: p < 10⁻⁶, n = 22 mice; Wilcoxon rank sum test).

(D) Photoinhibition decreased performance in expert mice (n = 15 mice). ^∗p < 0.05; Wilcoxon rank sum test. Error bars indicate SEM over mice. Dashed black line marks chance performance.