Building a motor simulation de novo: observation of dance by dancers

Abstract

Research on action simulation identifies brain areas that are active while imagining or performing simple overlearned actions. Are areas engaged during imagined movement sensitive to the amount of actual physical practice? In the present study, participants were expert dancers who learned and rehearsed novel, complex whole-body dance sequences 5 h a week across 5 weeks. Brain activity was recorded weekly by fMRI as dancers observed and imagined performing different movement sequences. Half these sequences were rehearsed and half were unpracticed control movements. After each trial, participants rated how well they could perform the movement. We hypothesized that activity in premotor areas would increase as participants observed and simulated movements that they had learnt outside the scanner. Dancers' ratings of their ability to perform rehearsed sequences, but not the control sequences, increased with training. When dancers observed and simulated another dancer's movements, brain regions classically associated with both action simulation and action observation were active, including inferior parietal lobule, cingulate and supplementary motor areas, ventral premotor cortex, superior temporal sulcus and primary motor cortex. Critically, inferior parietal lobule and ventral premotor activity was modulated as a function of dancers' ratings of their own ability to perform the observed movements and their motor experience. These data demonstrate that a complex motor resonance can be built de novo over 5 weeks of rehearsal. Furthermore, activity in premotor and parietal areas during action simulation is enhanced by the ability to execute a learned action irrespective of stimulus familiarity or semantic label.

Fig. 1

Stimuli and experimental design. The top row of the figure shows an example of part of a movie sequence observed by participants. Control and experimental video clips were randomly presented. After observing and imagining themselves performing the movements in each 5-s video clip, participants responded to a question asking how well they could presently perform the movement just observed.

Fig. 2

Dancers’ mean rating of their own ability to perform rehearsed and control movements, across scanning session. Ratings were based on a 1–4 scale, with 1 corresponding to the ability to perform the observed movement perfectly and 4 corresponding to being able to perform the observed movement poorly at present. Error bars represent standard error of the mean.

Fig. 3

Observation of all-dance, by dancers. Top row: left hemisphere, lateral and medial views. Bottom row: right hemisphere, lateral and medial views. All activations significant at the P < 0.05 level, uncorrected.

Fig. 4

Observation of rehearsed movement, compared to non-rehearsed, control movement, masked by all-dance activations (Fig. 3). Top row: left hemisphere, lateral and medial views. Bottom row: right hemisphere, lateral and medial views. All activations significant at the P < 0.01 level, uncorrected.

Fig. 5

Observation of rehearsed movement > observation of non-rehearsed movement, modulated by ratings of performance ability and masked by all-dance activations (Fig. 3). Figure depicts lateral and medial views of the left hemisphere, respectively. All activations significant at the P < 0.01 level, uncorrected.