Glial and Glutamatergic Deficits in Psychiatric Disorders

Stress-related psychopathology, including depression and PTSD, are debilitating and chronic illnesses affecting millions of people across the world. To compound the problem of high prevalence rates, there are limited effective pharmacologic treatment options for these disorders. Traditional antidepressants, though effective for some people, produce little to no clinical improvement for many and takes weeks to months to reach their full benefit. There is a great deal of interest in exploring how depression and PTSD seem to affect the brain as this may help to identify new treatment targets. Evidence from animal studies suggests there may be glial and glutamatergic impairment in stress-related psychopathology. However, until recently, investigations of glial function and prefrontal glutamate/glutamine cycling were not possible. Glutamate is one of the most common and widespread neurochemicals in our brains and has been correlated to many aspects of day-to-day function, including emotion and cognition, both integrally connected to PTSD and depression. Glial cells are involved in helping to regulate glutamate activity in the brain. It is suspected that people struggling with PTSD and depression may have altered glial and glutamatergic functioning. This study uses advanced, state-of-the-art neuroimaging methods to evaluate glial and glutamate functioning. The results of this study can further our understanding of the effect of stress-related psychopathology in the brain and the potential role of the glutamatergic system.

This study involves two neuroimaging scan visits. The first will gather data regarding the basic structure and function of the brain. The second visit uses a novel imaging method called carbon 13 magnetic resonance spectroscopy. Briefly, we used acetate (a naturally occurring and safe substance the brain uses for energy like glucose) with the carbon 13 molecules labeled. This allows us to monitor how the acetate is metabolized in the brain and to investigate glial and glutamatergic function.