Figure 3:

External inputs are required for the motor cortical pattern during reaching. a, Experimental schematic: placement of fibers over motor cortex and thalamus. b, Distribution of lift times on control (yellow) and thalamic inactivation (green) trials; n = 3 animals (VGAT-ChR2-EYFP), n = 7 sessions. Right inset shows the probability of a lift within the first 500 ms following the cue for control and thalamus inactivation trials. c, Hand position in the upper direction centered on lift on control trials (light yellow) and mid-reach thalamic inactivation trials (black; green indicates laser on) for a single dataset. Dots indicate the start of the laser. Data from all animals (n = 4 mice, n = 6 sessions) shown in Extended Data Fig. 6. d, Lift times for control trials (yellow), cortical inactivation (blue), and sequential inactivation of cortex and thalamus (green); n = 3 mice (VGAT-ChR2-EYFP), n = 4 sessions. e, Average firing rate Z-scores for all recorded neurons under inactivation of cortex alone (left) and sequential inactivation of cortex and thalamus (right); n = 3 mice, n = 4 sessions, n = 127 neurons. f, Population activity following the end of cortical inactivation for trials with cortical inactivation only (blue) and inactivation of thalamus after cortex (green). Plotting limits start 500 ms before the end of cortical inactivation and finish 500 ms after the cortical inactivation (blue trace) and 500 ms after the thalamic inactivation (green trace). The divergence of the trajectories shortly before the end of cortical inactivation is due to smoothing (Extended Data Fig. 5e–h), and inhibitory interneurons were excluded. g, Schematic illustrating that the divergence from the cortex-inactivated state reveals differences in input. h, Estimated difference in external inputs following the end of cortical inactivation between thalamus inactivated and not inactivated conditions.