Functional Magnetic Resonance Spectroscopy of Sensory Gating

Abstract

The advancement of medical imaging technology has allowed the development of functional magnetic resonance spectroscopy (fMRS)—a focused form of magnetic resonance imaging (MRI) that can determine the physical properties and relative concentrations of individual chemical compounds within living tissue. fMRS has allowed the study of various neurochemical changes that take place in the brain as a result of cognitive processes, such as object recognition and working memory. Furthermore, dysfunctions of neurochemical cycling systems have been implicated in psychiatric disorders, such as schizophrenia. Sensory input from the body passes through the thalamus, which regulates the intensity of the onward neural signals to the higher centres of the brain, allowing the prioritisation of attention. The study presented here sought to explore the concentrations of glutamine and glutamate in the thalamus by using a 3.0T fMRS scanner during participant exposure to audio stimuli that should induce this sensory gating process by presenting paired or unpaired clicks. No significant differences in the levels of glutamine or glutamate were identified upon exposure to any of the experimental conditions. The experimental methodology, consideration of the participants and the structure and function of the auditory systems are explored briefly to provide recommendations for further studies.