As also evident in Figure 2A, there was a similar monotonic decrease in the mean time to reach targets. Whereas the initial cursor trajectories meandered, they became more direct with practice (Figure 2D, comparison of representative trajectories from day 3 and day 13 for Monkey P). It is important to note that the subjects were not required to follow a straight path from the center to each target. Interestingly, the mean trajectory to each target became increasingly stereotyped over time, suggesting that a relatively stable solution emerged for the path to each target. We quantified the similarity between each set of daily mean trajectories by performing pairwise correlations (see Materials and Methods). As illustrated by the color map in Figure 2D, the correlation between the mean paths for each day initially increased and then stabilized. Similar results were obtained for Monkey R (see Figure S3)
Basically, they get better at moving the exoskeleton and/or cursor over time, they way a human does when learning a new physical skill. The possible extensions of this technology are somewhat apparent to anyone who had an interest in science fiction as a kid: once approved for human use, this same technology can be used to control artificial limbs, or to operate a computer (or other computer driven object) without having to use your hands. You can read the original article here for free.