The anesthetized mice were then moved to a sitting posture, with their heads fixed and their forelimbs hanging free (Figure 3A, center). With prolonged stimulus trains (500 ms), the forelimb tended to reach a final position within ∼300 ms and remain there for the duration of the stimulus. Stimulation

of Mab caused the contralateral forelimb to be raised and then brought learn more toward the midline, whereas stimulation of Mad typically produced rhythmic movements lower in space, often coupled with movement of the hindlimb (Figure 3B). These movements were reproduced in anesthetized mice where ChR2 was locally expressed using adeno-associated virus (Figure S2) and in awake, freely moving ChR2 transgenic mice stimulated within

Mab and Mad via optical fibers (Figures 3A and 3B, right; Movie S2). In both anesthetized and awake mice, the displacement of the limb from its starting position was buy Veliparib significantly greater when Mab was stimulated rather than Mad (Figures 3B and 3C). Although movement trajectories (Figure 3B) and displacements (Figure 3C) were clearly dependent on stimulus site for both awake and anesthetized mice, the speed profiles of Mab and Mad movements were nearly identical (Figure 3D). Movements evoked from each site were remarkably consistent from trial to trial, and the variability that they did exhibit had a temporal structure that depended on the site of stimulation (Figure S3). Increasing stimulus duration generally had little effect on movement map structure, despite changes observed in movement trajectories (Figure S4). Consistent with previous results from electrical stimulation (Ramanathan et al., 2006), modulating optogenetic stimulus intensity did not affect movement trajectories evoked by prolonged stimulation (Figure S5). These experiments complement the mapping study by exposing the distinct Cediranib (AZD2171) types of complex movement that

can be evoked from Mab and Mad by prolonged stimulation in both anesthetized and awake mice. To determine whether these complex movements require selective stimulation of layer 5B neurons, we compared optogenetic stimulation (500 ms train of 5 ms, 5 mW pulses at 100 Hz) with trains of electrical intracortical microstimulation (ICMS) targeted to layer 5 of cortex (500 ms trains of 200 μs, 100 μA pulses at 200 Hz) (Ramanathan et al., 2006). Given the differences between ICMS and optogenetic stimulation, we were surprised to discover that ICMS was able to closely reproduce the complex movements characteristic of transgenic or viral optogenetic stimulation of Mab and Mad (Figure 4A, Figure S2). In addition to their overlapping trajectories, movements evoked by either method had comparable peak displacements, time to peak, and angle from origin at peak displacement (Figure 4B).