[Seminar] "Neural Representations of Natural Self-Motion: Implications for Perception & Action " by Prof. Kathleen E. Cullen
A fundamental question in neuroscience is how does the brain compute accurate estimates of our self-motion relative to the world and orientation relative to gravity in everyday life. In this talk, I will describe recent findings from my laboratory’s research that have addressed this question and provided new insight into how vestibular pathways encode self-motion information to ensure accurate perception and motor control.
First, we have recently examined the statistics of natural self-motion signals experienced by mice, monkeys, and humans, and then explored the neural coding strategies used by early vestibular pathways. Focusing on the relationships between neural variability, detection thresholds, and information transmission, our findings have revealed that two distinct sensory channels represent vestibular information at the level of the vestibular periphery. Notably, more regularly discharging afferents have better detection thresholds and use rate coding, while more irregular afferents take advantage of precise spike timing (i.e, temporal coding) and are better optimized for processing natural vestibular stimuli.
Our research has also established that the neurons at the first central stage of vestibular processing are substantially less sensitive to active motion. Notably, this ability to distinguish between active and passive motion is not a general feature of early vestibular processing, but is instead a characteristic of a distinct group of neurons known to contribute to postural control and spatial orientation. Our most recent studies further indicate that multimodal integration within the vestibular cerebellum is required for this cancellation of self-generated vestibular information from the subsequent computation of orientation and posture control. Moreover, when unexpected vestibular inputs become persistent during active motion, indicating that this mechanism is rapidly updated to re-enable the vital distinction between active and passive motion to ensure the maintenance of posture. Finally, our recent findings have established that posterior thalamocortical vestibular pathway even more selectively encode unexpected motion, thereby providing a neural correlate for ensuring perceptual stability during active versus externally generated motion.
Acknowledgements: Funded by NIH/NIDCD R01-DC2390, the Canadian Institutes of Health Research (CIHR), Natural Sciences and Engineering Research Council of Canada (NSERC), and Canada Foundation for Innovation (CFI).
Kathleen Cullen is a professor in the Department of Biomedical Engineering and co-director of the Center for Hearing and Balance at Johns Hopkins University. She is also affiliated with the departments of Neuroscience and Otolaryngology, and is on the Board of the Kavli Neuroscience Discovery Institute.
Dr. Cullen’s research is aimed at understanding how the brain creates neural representations of our motion to ensure the maintenance of balance, posture, and accurate perceptual stability during everyday activities. She also studies neuronal activity and behavior before and after vestibular loss, and evaluates treatments (e.g., neuroprosthetic devices) designed to restore vestibular function and motor performance in patients.
Dr. Cullen has served on numerous editorial boards (i.e., Scientific Reports, Neuroscience, J. Neurosci., J. Neurophys. J. Res. Otolaryng.), as well as on the Scientific Advisory Board of the National Space Biomedical Research Institute, which works with NASA to identify health risks in extended space flight. She was honored with the Halpike-Nylen medal of the Barany Society for “outstanding contributions to basic vestibular science” and is vice president and program chair of the Society for the Neural Control of Movement. She has published more than 120 articles, book chapters and patent applications and given over 160 national and international invited lectures.