Ventromedial prefrontal cortex metabolite levels in obsessive-compulsive patients: a proton magnetic resonance spectroscopy study

Abstract

Studies of proton magnetic resonance spectroscopy (¹H MRS) indicate that obsessive-compulsive disorder (OCD) patients, when compared to healthy individuals, may present dysfunctional glutamatergic and GABAergic systems (the two main neurotransmitters in the central nervous system, that plays excitatory and inhibitory roles, respectively) in prefrontal and striatal brain regions. However, the literature remains controversial because there are no studies that have used ¹H MRS technique that allowed dissociating glutamate values (GLU) from glutamine (GLN): the fact that the metabolites appear overlapped (GLX) complicates a more detailed interpretation of the results. At the same time, particularly important for the neurobiology of OCD, the region of the ventral medial prefrontal cortex (CVM) has been characterized as one of the main regions associated with the disorder. Therefore, this project aims to study the amount of metabolites in the CVM of OCD patients and controls, with a new ¹H MRS pulse sequence which enables disentangling glutamate values from glutamine, and also to correlate these values with demographic and clinical data (such as age, sex and symptoms of OCD, depression or anxiety). As a secondary objective, the amount of the metabolites will be analyzed after three types of treatment for OCD: one conventional (serotonin reuptake inhibitor - sertraline) and two non-conventional (transcranial direct-current stimulation and radiosurgery by gamma rays). Finally, we will be able to analyze the responders and no responders to treatment, regardless of the treatment kind which they have been subjected. (AU)