Research Seminar - The MARCS Institute

Associate Professor Jorge Serrador from the Dept of Pharmacology & Physiology, Rutgers Biomedical Health Sciences and War Related Illness & Injury Study Center, Dept of Veterans Affairs will be presenting "Why space flight is like ageing: the vestibular-brain blood flow link".

Abstract: Spaceflight is associated with a number of adaptations that are very similar to those seen with aging. For example, both spaceflight and aging are associated with loss of muscle mass, loss of bone density and loss of balance. Both aging and spaceflight are also associated with increased incidence of orthostatic intolerance, or the inability to stay upright without fainting. One similarity in both groups is the loss of balance function. In both conditions the vestibular system has a reduced ability to detect gravity through the otolith organs, one because of loss of hair cells with aging, and the other because of a retraining of the brain to ignore the otoliths for perception of gravity because of adaption to zero gravity. We hypothesized that otolith mediated vestibular inputs would provide cues of position that would assist in maintaining brain blood flow when upright. To assess this we performed a series of experiments examining the role that the vestibular system may play in affecting cerebral blood flow. We found that direct stimulation of the vestibular system using centrifugation or tilt resulted in changes in cerebral blood flow that could not be explained either by changes in blood pressure or arterial CO2 levels. We further found that individuals with reduced otolith function demonstrated greater decreases in cerebral blood flow when upright. Finally, we used a new paradigm known as stochastic noise galvanic stimulation to improve vestibular function which resulted in enhanced cerebral blood flow during dynamic tilt with stimulation. These data demonstrate that reduced otolith function may be involved in orthostatic intolerance and that stochastic noise may be a possible method of restoring impaired function.