Neurocase The Neural Basis of Cognition ISSN: 1355-4794 (Print) 1465-3656 (Online) Journal homepage: https://www.tandfonline.com/loi/nncs20 Motor simulation theories of musical beat perception Jessica M. Ross, John R. Iversen & Ramesh Balasubramaniam To cite this article: Jessica M. Ross, John R. Iversen & Ramesh Balasubramaniam (2016) Motor simulation theories of musical beat perception, Neurocase, 22:6, 558-565, DOI: 10.1080/13554794.2016.1242756 To link to this article: https://doi.org/10.1080/13554794.2016.1242756 Published online: 11 Oct 2016. Submit your article to this journal Article views: 235 View Crossmark data Citing articles: 7 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=nncs20 NEUROCASE, 2016 VOL. 22, NO. 6, 558–565 http://dx.doi.org/10.1080/13554794.2016.1242756 REVIEW Motor simulation theories of musical beat perception Jessica M. Rossa, John R. Iversenb and Ramesh Balasubramaniam a aCognitive and Information Sciences, University of California, Merced, CA, USA; bSwartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego, CA, USA ABSTRACT ARTICLE HISTORY There is growing interest in whether the motor system plays an essential role in rhythm perception. The Received 1 May 2016 motor system is active during the perception of rhythms, but is such motor activity merely a sign of Accepted 22 September unexecuted motor planning, or does it play a causal role in shaping the perception of rhythm? We 2016 present evidence for a causal role of motor planning and simulation, and review theories of internal KEYWORDS simulation for beat-based timing prediction. Brain stimulation studies have the potential to conclusively Auditory perception; motor test if the motor system plays a causal role in beat perception and ground theories to their neural planning; motor simulation; underpinnings. rhythm; timing Introduction perceptual processes, and this bidirectional causality is a char- acteristic of the models and theories reviewed here. While A tight relationship between movement and auditory rhythm there is a long history of study in how the sensory systems perception is evident in human motor system response and inform action, there is now growing evidence that internal motor involvement during music listening and rhythm tasks forward models make predictions about the sensory conse- (Iversen & Balasubramaniam, 2016; Janata, Tomic, & quences of motor acts (Prinz, 1997; Wolpert & Flanagan, 2009). Haberman, 2012; Repp, 2005a; Repp, 2005b; Ross, These predictions are thought to contribute to sensory per- Warlaumont, Abney, Rigoli, & Balasubramaniam, 2016), and ception and error assessments used for making corrections for can be observed in neural response to music early in infant discrepancies between expected and actual sensory input. An development (Kuhl, Ramirez, Bosseler, Lin, & Imada, 2014). important task for music neuroscience is to understand to How we move to music has by itself become a systematic sub- what extent there is a bidirectional relationship between audi- field of inquiry (Ross et al., 2016) that often focuses on body tory perception and action during not only performance but synchronization with music. Some have suggested that the perception. link between auditory and motor involvement in music could In this review, we focus on the particular relationship be similar to that found in language (Patel, Iversen, & between motor planning and musical beat perception. We Rosenberg, 2006). examine neural and behavioral evidence for active motor Music often impels us to move in time with a perceived involvement in auditory rhythm perception, and contrast this pulse or beat, implying a forward connection between audi- with other general “motor” theories of action, and with motor tory and motor systems that enables sound to guide move- theories of speech perception. In particular, we examine the- ment planning and execution. Auditory training has been ories that posit the role of the motor system as “shadowing” or shown to improve motor performance (Stephan, Heckel, “mirroring” the auditory system and others that suggest that it Song, & Cohen, 2015) and has even been explored for move- may play a more causal or “predictive ” role without which ment rehabilitation in patients with Parkinson’s disease human musical beat perception would be impaired. In addi- (Nombela, Hughes, Owen, & Grahn, 2013; Thaut et al., 1996) tion, we discuss theories that move beyond the more literal and recovery after stroke (Altenmuller & Schlaug, 2013). prediction of sensory consequences of motor acts to a more Interestingly, motor planning regions are active even when abstract role of the motor system in generating temporal merely listening to music with a beat and not moving along. predictions. We propose causal methods, such as using tran- This raises the question: is the motor system necessary for scranial magnetic stimulation (TMS) protocols, as a necessary beat perception, or is such motor activity a consequence of experimental step to further define the causal role of the beat perception, reflecting unexecuted movement? The for- motor system in auditory rhythm perception. mer view, perhaps surprising at first if one considers “the beat” to be a property of the music itself, is consonant with the idea that perception and movement are intimately coupled in a Beat perception continuously interacting bidirectional perception–action rela- Beat perception refers to the detection of a regular pulse tionship (Gibson, 1966). This perception–action relationship underlying a rhythmic input stream. Beats can be stressed, or depends upon sensory perception to inform motor planning, accented, in regular patterns to help structure the pulse in a but suggests that the motor system may influence active CONTACT Ramesh Balasubramaniam [email protected] © 2016 Informa UK Limited, trading as Taylor & Francis Group NEUROCASE 559 predicable way, and this structure is referred to as meter Finally, beat perception is subject to influence by motor (Lerdahl & Jackendoff, 1983; London, 2004). The auditory behavior. Overt body movement can improve perception of stream may be as simple as a metronome or as complex as a timing (Manning & Schutz, 2013) and influence perceptual highly layered and time-varying musical work, but the human interpretation of ambiguous rhythms (Phillips-Silver & brain seems to almost automatically seek a simple regularity, Trainor, 2005, 2007). Overt and covert motor activities are the beat, or pulse, which can serve to organize our move- associated with changes to perceptual acuity. Recent studies ments (as in dance, or tapping your foot to music), but also have shown improvements in beat-perception and finger- can organize our perception of time (Hannon, Snyder, Eerola, tapping entrainment to music when subjects were instructed & Krumhansl, 2004; Palmer & Krumhansl, 1990). Two types of to search for the pulse by moving their bodies (Su & Pöppel, timing that are involved in rhythm perception are interval- 2012). Further research has shown that demonstrations of based (absolute) timing and beat-based (relative) timing (Dalla accelerating motion lead to faster perceived tempo of musical Bella et al., 2016; Grube, Lee, Griffiths, Barker, & Woodruff, excerpts (Su, 2012; Su & Jonikaitis, 2011). Taken together, 2010; Iversen & Balasubramaniam, 2016). Interval-based timing these results provide evidence that beat and meter perception is common to humans and non-human primates (Merchant & are shaped by motor activity. However, in this review we will Honing, 2014; Zarco, Merchant, Prado, & Mendez, 2009). Beat- focus largely on the less explored role of the motor system in based timing may be uniquely human among primates (e.g., beat perception when no overt movement is involved. Merchant & Honing, 2014), and has other properties that make it of special interest for motor theories of timing (Grube et al., Motor system activation during passive listening 2010; McAuley & Jones, 2003; Patel & Iversen, 2014). A number of findings support the notion that motor activ- A second strand of evidence suggesting the potential for a ity may play an active role in shaping beat perception. In motor role in beat perception comes from neuroimaging, particular, as reviewed in the following, it has been suggested which has repeatedly shown that parts of the motor planning that beat-based timing relies on the establishment and main- system are active during rhythm perception, even in the tenance of an internal predictive model, and there is support absence of overt movement, particularly for rhythms that for this in demonstrations of anticipation in motor synchroni- evoke a strong sense of beat. In particular, beat perception zation, tempo flexibility, the susceptibility of beat perception engages dorsal premotor cortex, supplementary motor area to willful control, and improved perceptual acuity of events (SMA), pre-SMA, basal ganglia, and lateral cerebellum that occur on the beat. (Bengtsson et al., 2009; Chen, Penhune, & Zatorre, 2008; Many empirical studies have concluded that beat percep- Grahn & Brett, 2007; Stupacher, Hove, Novembre, Schütz- tion is anticipatory in nature (Miyake, 1902; Repp, 2005b; Bosbach, & Keller, 2013). Although these activations are dis- Woodrow, 1932). Analyses of finger tapping movements that tributed across multiple regions, they are all in areas of the are synchronized with