Title: Galvanic Vestibular Stimulation and Computational Models of Human Vestibular Processing

Presenter: Dr. Torin Clark, Associate Professor, Bioserve Space Technologies, College of Engineering and Applied Science, University of Colorado Boulder

Abstract: The vestibular system, in the inner ear, senses motion and orientation of our heads, critical for balance and other functions. Galvanic vestibular stimulation (GVS) applies low levels of electrical current to the mastoids, behind the ears, to artificially stimulate the vestibular system. Here we explore potential applications of (GVS), beginning with use as an alternative display modality to visual and auditory displays. We find that "bursts" of sinusoidal GVS waveforms can be reliably distinguished by modulating the frequency and that this is robust to different environments (in the dark, light, sitting, standing, etc). Further, these GVS cues are not destabilizing, such that they could be used to operational environments (e.g., to signal a firefighter). Next, we explore applying noisy GVS waveforms aimed at producing stochastic resonance. In addition to improving (i.e., reducing) vestibular (self-motion) perceptual thresholds, we find evidence of cross-modal stochastic resonance, improving visual, auditory, and tactile perceptual thresholds. Transitioning to computational models of spatial orientation perception, we analyze visual-vestibular integration during transitions in the availability of visual cues. Such models could be used in real-time to identify if an aircraft pilot is spatial disoriented and trigger and pilot aiding system to prevent accidents and improve performance. Finally, we leverage the model to consider the computations the brain may use to reinterpret sensory cues during gravity transitions (e.g., landing on the moon). In a Bayesian framework with parallel alternative hypotheses for the magnitude of gravity, the brain could dynamically update a probability distribution to minimize sensory conflict. We implement and simulate the model to quantify predictions for the time course of adaptation to altered gravity. 

Bio: Torin Clark is an Associate Professor in the Smead Aerospace Engineering Sciences Department and Biomedical Engineering Program at CU-Boulder. He is a member of the Bioastronautics Laboratory and faculty affiliate of BioServe Space Technologies.

His research is focused on the challenges that humans face during space exploration missions. This includes astronaut biomedical issues, space human factors, human sensorimotor/vestibular function and adaptation, interaction of human-autonomous and human-robotic systems, mathematical models of spatial orientation perception, and human-in-the-loop experiments. 

https://www.colorado.edu/faculty/clark-torin/