Although we have had a tremendous success studying our traditional cohorts over the years, there have been a number of limitations. For MRS studies in a practical amount of time, only single voxel spectroscopy has been feasible. For other neuropsychiatric patients, the MRI environment can be poorly tolerated, limiting the length of fMRI paradigms. As we have brought other MR technologies to bear on these subjects (functional connectivity studies, DTI, voxel based morphometry (VBM)) the length of the studies have become intolerable for all but the most compliant individuals. New MRI hardware and software developments are key to faster, more inclusive studies.
Schizophrenia. The group is studying the key nodes of the glutamatergic circuit proposed by Dr. Williamson with 3-dimensional 1H CSI developed by Théberge on the 7T. They are examining the functional integrity of glutamatergic signaling with functional MRS. Psychotic patients generally have difficulty tolerating lengthy scans but the faster imaging acquisition with the newer multi-channel coils will allow us to complete 7T MRS and 3T VBM, DTI and fMRI studies in the same patients. With advanced analysis techniques like Fusion Independent Component Analysis that fuse data from different modalities, the group seeks to uncover the final common pathway of this disorder. Understanding the final common pathways for psychiatric conditions will advance our diagnostic understanding and open avenues for greatly improved treatment for patients.
Mood and Anxiety Disorders. Patients with major depression disorder demonstrate an inability to see themselves, the world, or the future in a positive way, while those with a bipolar disorder experience episodes when they have the opposite problem. Williamson and Allman have proposed that another neuronal circuit associated with emotional encoding underlie these disorders. These circuits also utilize glutamate. Dr. Osuch is characterizing the final common pathways of these disorders with the same tools described above. Her goal will be to not only distinguish schizophrenia from mood disorders but also unipolar from bipolar depression which has important clinical implications for treatment and caregivers.
Post Traumatic Stress Disorders. Patients with PTSD experience intrusive memories, intensely distressing emotions (e.g. shame, anger) and disturbances in sense of self. In a series of very highly cited studies Dr. Lanius, with Williamson, Théberge and Menon demonstrated that patients with PTSD are unable to encode traumatic events into episodic memory due to the dysfunction of prefrontal and other neuronal circuits induced by high levels of stressand demonstrated the neuronal circuits of out-of-body experiences induced by extreme stress. PTSD patients are very difficult to study in the scanner but faster acquisitions and quieter sequences will allow us to characterize neuronal changes associated with different PTSD presentations, examine whether we can predict who will develop PTSD on the basis of brain imaging signatures, and track brain imaging parameters associated with treatment outcome. Incorporation of the EGI Geodesic EEG equipment will be a novel research direction for the latter goal as Dr. Lanius is developing and studying the use of neurofeedback treatment approaches in PTSD based on combined EEG and fMRI.