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Understanding the Sensorimotor Neuroscience of Cycling
Secondary Supervisor(s): Dr Raymond Reynolds
University of Registration: University of Birmingham
BBSRC Research Themes: Understanding the Rules of Life (Neuroscience and Behaviour)
Project Outline
Despite the long history of bicycle use, we still lack a clear understanding of how we balance and manoeuvre them. Balancing on a bicycle differs from balancing on foot; it requires moving—specifically turning the handlebars—towards the direction of falling, a strategy not used elsewhere by our brains (see video: https://tinyurl.com/yjc2k9s4). Additionally, bicycle dynamics challenge the fundamental assumption in human motor control that less movement ensures greater stability. A stationary bicycle is inherently unstable and becomes more stable as it gains speed, contradicting the conventional "speed-accuracy trade-off." In cycling, higher speeds can actually be advantageous when navigating narrow paths. These unique mechanical characteristics necessitate redefining existing frameworks for studying human sensorimotor control exclusively for bicycling.
This project brings together experts in biomechanics and motion analysis (Yeo) and vestibular sensorimotor control (Reynolds) to tackle these questions. We will utilise state-of-the-art devices recently built in the School of Sport, Exercise, and Rehabilitation Sciences of the University of Birmingham, including a large-scale, high-speed motion capture studio, wireless muscle electromyography, and musculoskeletal simulation software. Using these tools, we will address two primary questions:
How do we balance a bicycle? We will explore the impact of manipulating the rider's balance using galvanic vestibular stimulation (GVS), a non-invasive neuromodulation technique that mildly perturbs the vestibular nerve to produce a sense of head rotation [1]. It is expected that GVS perturbations in different head orientations during cycling will produce balancing behaviour radically different from those observed in walking experiments, due to the idiosyncratic characteristics of bicycle balancing mentioned above. Based on this experiment, we aim to understand how humans adapt their balancing control to cope with the dynamics of bicycling.
How do we steer a bicycle? Given the unique dynamics of bicycling, it is expected that bicycle riding violates fundamental models of human motor control. Specifically, models like Accot & Zhai's steering law [2] —which assumes that slower movement is required for narrower paths—may not apply. We will investigate how different path geometries affect the preferred speed and steering behaviour of cyclists, aiming to develop new computational model of motor control tailored to bicycling [3].
The expected outcomes will advance our understanding of the brain's mechanisms in controlling bicycling, particularly how multisensory information—integrating vision, vestibular, and proprioceptive cues—is coordinated to support balance and steering. This project will make a fundamental contribution to our understanding of human sensorimotor control, with potential implications for systematically addressing safety factors in cycling behaviour. The PhD student will collaborate closely with supervisors, primarily leading the experimental design, data collection, and analysis.
References
[1] Reynolds, R. F., & Osler, C. J. (2012). Galvanic vestibular stimulation produces sensations of rotation consistent with activation of semicircular canal afferents. Frontiers in neurology, 3, 104.
[2] Accot, J., & Zhai, S. (1997, March). Beyond Fitts' law: models for trajectory-based HCI tasks. In Proceedings of the ACM SIGCHI Conference on Human factors in computing systems (pp. 295-302).
[3] Yeo, S. H., Franklin, D. W., & Wolpert, D. M. (2016). When optimal feedback control is not enough: Feedforward strategies are required for optimal control with active sensing. PLoS computational biology, 12(12), e1005190.
