Synchronizing our movements to rhythmic sounds is a complex behavior, but easy for many humans, whether in the form of playing an instrument, dancing, or simply nodding/ tapping along to a musical beat. How is this feat accomplished? A Hebbian hypothesis would argue that when sounds and movements co-occur, the systems become strongly associated, however many children exhibit a rhythmic sensitivity and do not seem to require training to move in time with music. An alternate explanation is that the motor system provides top down constraints to auditory processing (e.g. prediction and sequencing), such that the movement centers are already synchronized to external auditory cues prior to movement. In this dissertation I introduce three different electro-encephalography (EEG) studies that compare listening to, and moving along with rhythmic sounds, and explore the sensitivities of cortical motor rhythms to newly acquired action-sound pairings. In the first study I taught piano naive subjects to play a piano melody by ear and observed their motor rhythms showing preferential engagement when listening to the learned melodic sequence compared to unlearned melodies. In the second experiment, I compared the brainwave responses before and after subjects tapped or heard a tone and observed differences in motor rhythms in the time window before the events, but similarities in motor rhythm responses after sounds and after movements. In the third study, I introduce a novel EEG task - rhythmic hand drumming. I found that experienced drummers show greater engagement of motor rhythms while drumming than novice drummers, but across all subjects, motor rhythms were observed to modulate in time with drum rhythms regardless of whether subjects were just listening, or drumming themselves. Taken together, these three studies indicate that the motor system is sensitive to both rhythmic timing effects, and sequential effects of pitch order, and support a role for the motor system in auditory processing, when not otherwise engaged by movement

Our motor and auditory systems are functionally connected during musical performance, and functional imaging suggests that the association is strong enough that passive music listening can engage the motor system. As predictive coding constrains movement sequence selections, could the motor system contribute to sequential processing of musical passages? If this is the case, then we hypothesized that the motor system should respond preferentially to passages of music that contain similar sequential information, even if other aspects of music, such as the absolute pitch, have been altered. We trained piano naive subjects with a learn-to play-by-ear paradigm, to play a simple melodic sequence over five days. After training, we recorded EEG of subjects listening to the song they learned to play, a transposed version of that song, and a control song with different notes and sequence from the learned song. Beta band power over sensorimotor scalp showed increased suppression for the learned song, a moderate level of suppression for the transposed song, and no suppression for the control song. As beta power is associated with attention and motor processing, we interpret this as support of the motor system's activity during covert perception of music one can play and similar musical sequences.

Autism spectrum disorder (ASD) is a neurodevelopmental condition exhibiting impairments in behaviour, social and communication skills. These deficits may arise from aberrant functional connections that impact synchronization and effective neural communication. Neurofeedback training (NFT), based on operant conditioning of the electroencephalogram (EEG), has shown promise in addressing abnormalities in functional and structural connectivity. We tested the efficacy of NFT in reducing symptoms in children with ASD by targeting training to the mirror neuron system (MNS) via modulation of EEG mu rhythms. The human MNS has provided a neurobiological substrate for understanding concepts in social cognition relevant to behavioural and cognitive deficits observed in ASD. Furthermore, mu rhythms resemble MNS phenomenology supporting the argument that they are linked to perception and action. Thirty hours of NFT on ASD and typically developing (TD) children were assessed. Both groups completed an eyes-open/-closed EEG session as well as a mu suppression index assessment before and after training. Parents filled out pre- and post-behavioural questionnaires. The results showed improvements in ASD subjects but not in TDs. This suggests that induction of neuroplastic changes via NFT can normalize dysfunctional mirroring networks in children with autism, but the benefits are different for TD brains.

Despite rapid advances in sensor development and technological miniaturization, it remains challenging to non-invasively record small-amplitude electrophysiological signals from an animal in its natural environment. Many advances in ecophysiology and biologging have arisen through sleep studies, which rely on detecting small signals over multiple days and minimal disruption of natural animal behavior. This paper describes the development of a surface-mounted system that has allowed novel electrophysiological recordings of sleep in wild marine mammals. We discuss our iterative design process by providing sensor-comparison data, detailed technical illustrations, and material recommendations. We describe the system’s performance over multiple days in 12 freely moving northern elephant seals (Mirounga angustirostris) sleeping on land and in water in captivity and the wild. We leverage advances in signal processing by applying independent components analysis and inertial motion sensor calibrations to maximize signal quality across large (> 10 gigabyte), multi-day datasets. Our study adds to the suite of biologging tools available to scientists seeking to understand the physiology and behavior of wild animals in the context in which they evolved.