Fig. 4: Regions with conjunction of ALM input–output connectivity contribute to motor planning behavior.
From: Activity map of a cortico-cerebellar loop underlying motor planning
a, Top, photostimulation is delivered using a scanner laser through a clear-skull implant. Bottom, a grid of 4 × 4 photostimulation locations (1-mm spacing). See alignment of the photostimulation locations into the CCF in Extended Data Fig. 8a. The photostimulation is over the left hemisphere. Each location was chosen randomly for photostimulation during the sample, delay or response epoch (n = 4 mice). In separate experiments, we tested one posterior location outside the 4 × 4 grid (posterior 4.1 mm, lateral 0.5 mm from lambda, n = 7 mice). Red circles indicate the two example photostimulation locations shown in b. b, Top, task and photostimulation timeline. Bottom, performance (percentage correct) after photostimulation in two example spots during specific epochs. ‘Lick left’ (red) and ‘lick right’ (blue) trials were grouped by instructed lick directions. Thick lines indicate the mean; thin lines indicate individual mice (n = 4). Open circles indicate performance in control trials; solid dots indicate photostimulation trials. Lick right trials, spot a, ***P = 0.00059 in delay epoch, ***P = 0.00043 in response epoch; spot b, ***P = 0; lick left trials, spot a, **P = 0.0185 in response epoch. Bootstrap, one-sided test, adjusted for multiple comparisons (Methods). c, Cerebellar regions involved in delayed response task during sample, delay and response epochs. Color codes for the change in performance (percentage correct) under photostimulation relative to control (∆ performance). Performances in ‘lick right’ (top row) and ‘lick left’ (bottom row) trials are shown separately. Trials across all photostimulation powers were combined (1–4 mW; Methods). Dot size codes for significance from bootstrap (Methods). For the 4 × 4 grid photostimulation, n = 4 mice; for the posterior spot photostimulation, n = 7 mice. d, Effect of delay epoch photostimulation across cerebellar regions defined by ALM input–output connectivity. Left, the photostimulation spots were grouped into conjunction regions (green dots), input-dominant regions (yellow dots) or output-dominant regions (blue dots). White dots indicate spots outside the cerebellum. Right, averaged ∆ performance in ‘lick right’ trials. Kruskal–Wallis one-way ANOVA, H(3) = 13.22, P = 0.0041. Post hoc pair-wise Mann–Whitney U test, conjunction versus input-dominant, *P = 0.034; conjunction versus output-dominant, *P = 0.016; conjunction versus outside regions, *P = 0.016. Error bars indicate the s.e.m. across photostimulation spots. Conjunction region, 5 spots from 11 mice; input region, 3 spots from 4 mice; output region, 5 spots from 4 mice; outside region, 4 spots from 4 mice. The slight performance decrease when photostimulation occurred outside the cerebellum may be caused by light scattering through the intact skull, which may affect parts of the cerebellum. NS, not significant.
