The neural basis of audiomotor entrainment: an ALE meta-analysis

Abstract

Synchronization of body movement to an acoustic rhythm is a major form of entrainment, such as occurs in dance. This is exemplified in experimental studies of finger tapping. Entrainment to a beat is contrasted with movement that is internally driven and is therefore self-paced. In order to examine brain areas important for entrainment to an acoustic beat, we meta-analyzed the functional neuroimaging literature on finger tapping (43 studies) using activation likelihood estimation (ALE) meta-analysis with a focus on the contrast between externally-paced and self-paced tapping. The results demonstrated a dissociation between two subcortical systems involved in timing, namely the cerebellum and the basal ganglia. Externally-paced tapping highlighted the importance of the spinocerebellum, most especially the vermis, which was not activated at all by self-paced tapping. In contrast, the basal ganglia, including the putamen and globus pallidus, were active during both types of tapping, but preferentially during self-paced tapping. These results suggest a central role for the spinocerebellum in audiomotor entrainment. We conclude with a theoretical discussion about the various forms of entrainment in humans and other animals.

Keywords: ALE; acoustic; basal ganglia; cerebellum; entrainment; finger tapping; meter; timing.

Figure 1

Conjunction between the externally-paced and self-paced ALE maps. The analysis is p < 0.01, FDR corrected. The 3D brain is shown to indicate the slice levels. The slices are shown in neurological convention. Abbreviations: IPL, inferior parietal lobule; L, left; PMCv, ventral part of the premotor cortex; R, right; S1, primary somatosensory cortex; SMA, supplementary motor area; SMC, sensorimotor cortex.

Figure 2

Contrast analysis between the externally-paced and self-paced ALE maps. The analyses are p < 0.05, uncorrected. The activations are color-coded according to the legend at the right. The 3D brain is shown to indicate the slice levels. The slices are shown in neurological convention. Note that the large activation in the right SMC and the corresponding activation in the left lateral cerebellum are simply a reflection of the larger number of left-handed studies for self-paced tapping (see text). Abbreviations: IPL, inferior parietal lobule; L, left; PMCd, dorsal part of the premotor cortex; R, right; SMC, sensorimotor cortex; SPL, superior parietal lobule.

Figure 3

Individual ALE maps for the three types of pacing studied. The analyses are p < 0.01, FDR corrected. The slices are shown in neurological convention. Abbreviations: IFG, inferior frontal gyrus; L, left; pSTG, posterior superior temporal gyrus; R, right; SMA, supplementary motor area; SMC, sensorimotor cortex.

Figure 4

Major categories of human pacing. The figure summarizes the three major types of pacing. Examples of each type are shown below the boxes.

Figure 5

Sonorant vs. non-sonorant movements. This figure is similar to Figure 4 but adds new distinctions related to sonorance, leading/following, and the sensory modalities for external entrainment.

Figure 6

A diversity of entrainment types in dancers and musicians. Red arrows suggest external pacing, while purple arrows suggest mutual pacing. Black figures are leaders while white figures are followers. Regarding external pacing, the dancers are acoustically paced by the music, while the musicians are visually paced by the conductor. Mutual pacing is seen at two levels for the dancers: (1) within each couple (through both kinesthetic and visual interactions), and (2) between the “lead” couple in the center and the two outer couples (through visual interactions alone). Such pacing is non-sonorant. Mutual pacing is also seen at top among the four musicians of the ensemble, but this pacing is sonorant. In the case of mutual pacing, each individual or group of individuals can serve as both a leader and a follower, with the role alternating in an adaptive fashion. However, when individuals or groups are externally paced, they are purely followers.