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Auditory-sensorimotor brain function during mental imagery of musical pitch and rhythm
thesisposted on 2022-03-28, 17:16 authored by Rebecca W. Gelding
This thesis examined how the auditory and sensorimotor regions of the human brain function and interact to support mental imagery of musical pitch and rhythm. Three sets of experiments were designed to: (1) develop and validate novel musical imagery tasks that address some prominent drawbacks of previous paradigms, and are suitable for use in magnetoencephalography (MEG) neuroimaging studies; (2) measure auditory sensorimotor brain function during mental imagery of musical pitch; (3) measure auditory-sensorimotor brain function during mental imagery of musical rhythm. Pitch imagery was studied using a Pitch Imagery Arrow Task (PIAT). Behavioural testing showed that the task reliably induced imagery in participants with a range of musical training and that performance was correlated with scores on an established psychometrictest of imagery ability (BAIS). Item Response Theory analysis showed that the taskrequires the ability to both maintain and manipulate pitches and overcome perceptualbiases. Rhythm imagery was studied using a Rhythm Imagery Task (RIT), and performance was found to improve after short-term tapping training. Individual differences in auditory imagery vividness and mental control were found to be more important for pitch than rhythm imagery. During both pitch and rhythm imagery, MEG beta-band activity was modulated in a similar manner in both auditory and sensorimotor source regions, indicating coordination of activity between these regions. Individual differences in imagery ability were related to greater sensorimotor to auditory directed connectivity. Finally, short-term motor training modulated the amount of right sensorimotor activity during rhythm imagery. These results support the interpretation that musical imagery is associated with coordinated activity in these regions; that the left cerebral hemisphere plays a dominant role in pitch imagery manipulation and that sensorimotor activity in the right cerebral hemisphere is particularly important for tracking rhythm. These contributions to knowledge have implications for music education and for therapeutic interventions for disorders of hearing, memory or motor function.