Moving to the beat: The relationship between rhythm perception and movement
Despite the amazing level of shared neural machinery between humans and nonhuman
primates, only humans appear to spontaneously ‘feel the beat’ in rhythm. Moving to the beat has
played a significant role in human culture for millennia, but the mechanism underlying beat
perception is still a mystery. Existing models of time perception cannot account for many
features of beat perception, and behavioral evidence suggests that humans may have a unique
beat-based timing system. My research seeks to characterize this system. Thus far, my research
indicates a link between beat perception and movement: brain areas that control movement
respond to rhythm, and certain motor areas respond specifically during beat perception, even
when no movement is made. My research will continue to investigate the beat-based system with
three inter-related streams that aim to: i) understand the neural mechanisms of rhythm and beat
perception, ii) compare brain responses across species, assessing whether beat perception is truly
unique to humans, iii) exploit beat-based mechanisms for gait interventions in movement
The first stream will examine what roles are played by the individual motor areas that
respond during rhythm and beat perception. Some roles may be general to all types of timing,
whereas others may be specific to beat-based timing. To investigate this, I will apply noninvasive
brain stimulation to transiently disrupt functioning in individual motor areas, measuring how
each supports timing and beat perception.
Most non-human primates can time the short intervals that make up rhythms, but appear insensitive to the beat. Beat perception may be unique to humans, or primates may perceive the beat, but have not been tested with paradigms that can demonstrate beat sensitivity. Therefore, I will compare brain responses in humans and other primates to beat-based sequences and nonbeat-based sequences, using non-invasive 7 Tesla MRI. If the brains of other primates distinguish beat and nonbeat sequences, this challenges the currently held view that beat perception is uniquely human.
In humans, beat perception not only activates motor areas, but enhances communication
between auditory and motor areas in the brain, providing a pathway by which sound can
influence movement. My third research stream will exploit this connection, characterizing how
selected rhythmic and musical characteristics alter walking, enabling us to select optimal music
features for gait interventions for patients with movement disorders, such as Parkinson’s disease.
I will also characterize the neural pathways that enable different features of music and rhythm
features to improve movement at an individual level. Currently, patients’ responses to musical
gait interventions vary widely. My goal is to assess and account for these individual differences
and thus tailor musical interventions to individual patients.
Understanding the neurobiological foundations of beat perception and rhythm will shape
future theories about our fundamental timing capacities and their underlying mechanisms.
Determining whether some capacities, such as beat-based timing, are uniquely human will be
crucial to creating accurate models of timing and temporal perception. These models will have
widespread applicability, as temporal perception underlies our capacity to integrate information
from different senses, coordinate movement, and perceive relationships in the world.