Multiple sensory cues are generated by discrete events (e.g., the vestibular-visual signals after hitting a pothole) and while they do not reach the cerebrum simultaneously, the brain can synthesize them if they are interpreted as corresponding to a single event. This is critical because the central representation of an event is improved if two or more relevant cues are integrated but conversely is degraded if unrelated inputs are synthesized. Little research has focused on temporal binding of vestibular signals with other sensory cues, even though the vestibular system operates in an inherently multimodal environment, and virtually nothing is known about temporal binding abnormalities in patients with peripheral or central vestibular disorders. The investigators will use psychophysical tests (quantifying the PSS [point of subjective simultaneity] and TBW [temporal binding window]) to study vestibular temporal binding in normal people, patients with combined vestibular and cochlear prostheses, and patients with peripheral or central vestibular dysfunction. The researchers will investigate two fundamental aspects of temporal binding: its dependence on signal precision and adaptation driven by habitual exposure to sensory patterns. Furthermore, the researchers will investigate how and why temporal binding differs from normal in patients with peripheral and central vestibular dysfunction.
Multiple sensory cues are typically generated by discrete events, and while they do not reach the cerebrum simultaneously, the brain can bind them temporally if they are interpreted as corresponding to a single event. The temporal binding of vestibular and non-vestibular sensory cues is poorly understood and has not been studied in detail, despite the fact that the vestibular system operates in an inherently multimodal environment. In this study, the researchers are investigating the physiology and pathophysiology of vestibular temporal binding by studying normal subjects, patients with peripheral and central vestibular dysfunction, and patients with vestibular and cochlear signals provided by prosthetic implants in the inner ear.