No movement is executed in isolation. In real life, we produce a constant stream of actions, with the next movement being already selected and planned while the current movement is still being executed. Many skills, such as typing, playing an instrument or tying a knot, rely on complex sequences of movements, sometimes practiced and rehearsed, sometimes flexibly assembled just in time.

How does the brain plan and execute movements at the same time? How do we become better at concatenating simple movements into a skillful whole? What neural representations underlie the production and learning of sequence movements? To answer such questions, we are combining carefully designed behavioral experiments, high-resolution functional magnetic resonance imaging (fMRI), representation analysis tools, and computational modelling.

Using a pattern classification we established that we can decode the sequence identity from the fine-grained (~2.3mm3) fMRI activity patterns of participants performing several 5-item sequences after a few day of practice (Wiestler and Diedrichsen, 2013). In further studies we then asked how sequences are represented in different brain regions. For example, we have shown that the temporal (i.e., time intervals between presses) and ordinal (i.e., order of fingers in a sequence) features of sequences are stored in partly separated areas including PMd, SMA, and SPL (Kornysheva and Diedrichsen, 2014). We also were able to show that the representation in rostral PMd reflect the instructional cue, while more caudal areas represent the actual finger movement (Wiestler et al., 2014). We have shown clear evidence for the hierarchical sequence organization across premotor and parietal areas (Yokoi and Diedrichsen, 2019), while M1 represents only individual finger movements (Yokoi et al., 2018). We have also demonstrated clear learning-related changes within premotor and parietal areas, but not in M1 (Berlot et al., 2020).

The most recent work in the lab directly addresses the question of how the brain plans future movements, while controlling present actions. We have shown evidence that the brain plans approx. 3 movements ahead (Ariani et al. 2020, 2021) and are now looking how these pre-planning process are coordinated and how they are realized in the brain.

Relevant papers