Dynamics of brain activity in motor and frontal cortical areas during music listening: a magnetoencephalographic study Mihai Popescu, Asuka Otsuka, and Andreas A. Ioannides * Laboratory for Human Brain Dynamics, Brain Science Institute, RIKEN, Wako, Saitama, 351-0198, Japan Received 26 August 2003; revised 11 November 2003; accepted 13 November 2003 There are formidable problems in studying how ‘real’ music engages the brain over wide ranges of temporal scales extending from milliseconds to a lifetime. In this work, we recorded the magneto- encephalographic signal while subjects listened to music as it unfolded over long periods of time (seconds), and we developed and applied methods to correlate the time course of the regional brain activations with the dynamic aspects of the musical sound. We showed that frontal areas generally respond with slow time constants to the music, reflecting their more integrative mode; motor-related areas showed transient-mode responses to fine temporal scale structures of the sound. The study combined novel analysis techniques designed to capture and quantify fine temporal sequencing from the authentic musical piece (characterized by a clearly defined rhythm and melodic structure) with the extraction of relevant features from the dynamics of the regional brain activations. The results demonstrated that activity in motor- related structures, specifically in lateral premotor areas, supplemen- tary motor areas, and somatomotor areas, correlated with measures of rhythmicity derived from the music. These correlations showed distinct laterality depending on how the musical performance deviated from the strict tempo of the music score, that is, depending on the musical expression. D 2004 Elsevier Inc. All rights reserved. Keywords: Music; Magnetoencephalography (MEG); Primary motor cortex; CURRY; Rhythm Introduction Both music and language rely on form and tempo to capture and communicate cognitive and emotional schemata that can be shared by different people. Nowadays human communication is dominated by language, but the formal similarities and dissim- ilarities of music and language suggest that music predates lan- guage by a long time (Merker, 2000). In general, sound perception triggers brain processes at distinct cortical regions, often lasting just a few milliseconds. Music cognition and appreciation on the other hand require seconds for a musical phrase to be established: first, what might be called the ‘primitive archetypes’ of music syntax must be identified (Marcus et al., 2003), and then integrated within a wider unfolding (musical) context. Thus, music perception involves a wide spectrum of cerebral responses, from activations that dynamically reflect the time structure of the stimulus at the level of resolution of individual notes (i.e., at fine temporal scales), to activations whose dynamics track the most global contour of accumulating interest or tension (i.e., at coarse temporal scales). Ideally, we need to map cortical activations with good spatial accuracy and with temporal resolutions that extends from milli- seconds to seconds to identify processes that might mirror the complex, hierarchical structural information present in a piece of authentic music. The formidable problems that such a study of brain processes entails has limited most earlier studies to contrast- ing congruent versus incongruent terminal notes in short note sequences. Motivated by these considerations, we used the excep- tional temporal resolution and good spatial localization of magne- toencephalography (MEG) to analyze the neural activity elicited by the unfolding of a passage of authentic music in real time. Early psychophysical studies (Dowling and Harwood, 1986; Fraisse, 1982; Handel, 1989) suggested that rhythmic information is more salient than pitch for music cognition. Tapping of feet and fingers to music is just the behavioral tip of a deep relationship between music perception and movement generation (Trevarthen, 1999). Tapping makes explicit the primacy of rhythm, and it is but one of the many manifestations of effortless induction of move- ment elicited by musical rhythm. Insights gained about internal representation of serial temporal pattern together with movements in synchrony with the musical rhythm have promoted a motor theory of musical rhythm perception (Seifert et al., 1995; Todd, 1992). More recent electrophysiological and pharmacological studies suggested that rhythmic timing might be accomplished by temporal pattern generators originating in the motor cortex (Arshavski et al., 1997) or temporally predictable changes in the activity of buildup cells in supplementary motor areas (SMA), which gradually increase their activity before movement (Matsu- zaka et al., 1992). In addition, it has been suggested that the cerebellum plays an important role in motor timing (Ivry and Keele, 1989). Neuroimaging studies of rhythm perception and reproduction also strengthened the hypothesis that the circuitry used for timing of brief intervals is likely to be located within the motor system, 1053-8119/$ - see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.neuroimage.2003.11.002 * Corresponding author. Laboratory for Human Brain Dynamics, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako, Saitama 351- 0198, Japan. Fax: +81-48-467-9731. E-mail address: ioannides@postman.riken.go.jp (A.A. Ioannides). Available online on ScienceDirect (www.sciencedirect.com.) www.elsevier.com/locate/ynimg NeuroImage 21 (2004) 1622 – 1638