Doctor of Philosophy
Dr. Jessica Grahn
Music is a universal human behaviour, is fundamentally temporal, and has unique temporal properties. This thesis presents research on the cognitive neuroscience of the temporal aspects of music: rhythm, beat, and metre. Specifically, this work investigates how cultural experience influences behavioural and neural measures of rhythm processing, and the different neural mechanisms (with particular interest in the role of the striatum) that underlie different stages of beat perception, as musical rhythms unfold.
Chapter 1 presents an overview of the existing literature on the perceptual, cognitive, and neural processing of rhythm, including the entrainment of neural oscillations to rhythm and the neuroanatomical substrates of rhythm perception.
Chapter 2 presents research on cross-cultural differences in the perception and production of musical rhythm and beat. Here, East African and North American participants performed three tasks (beat tapping, rhythm discrimination, and rhythm reproduction) using rhythms from East African and Western music. The results indicate an influence of culture on beat tapping and rhythm reproduction, but not rhythm discrimination.
Chapter 3 presents electroencephalographic (EEG) research on cross-cultural differences in neural entrainment to rhythm and beat. The degree to which neural oscillations entrained to the different regular ‘metrical levels’ of rhythms differed between groups, suggesting an influence of culture. Moreover, across all participants, the proportion of trials in which different rates were tapped was correlated with the degree of neural entrainment to those rates.
Chapter 4 presents functional magnetic resonance imaging (fMRI) research on the different neural mechanisms that underlie the different stages of beat perception (finding, continuation, and adjustment). Distinct regions of the striatum (dorsal vs. ventral putamen) were active to different extents in beat finding and adjustment, respectively. Activity in other regions (including the cerebellum, parietal cortex, supplementary motor area, and insula) also differed between stages. Additionally, when rhythms were metrically incongruent (polyrhythmic), additional activity was found in superior temporal gyri and the insula.
Chapter 5 presents a general discussion of Chapters 2-4 in the context of the existing literature, limitations, and broader interpretations of how these results relate to future directions in the field.
Cameron, Daniel J., "The Neural Mechanisms of Musical Rhythm Processing: Cross-Cultural Differences and the Stages of Beat Perception" (2016). Electronic Thesis and Dissertation Repository. 4193.
Available for download on Wednesday, August 01, 2018