Biomarkers for major psychiatric disorders
Mental disorders such as major depression and anxiety disorders are eminent personal burdens and also result in considerable costs for society. Recent developments in neuroscience and neuroimaging research hold great promise for obtaining a more comprehensive knowledge of the dysfunctional mental processes underlying these disorders. The primary objective of this type of research is to identify neurobiological markers of mental disorders. However, this objective might be achieved by combining different neuroimaging techniques in a multimodal, interdisciplinary and translational research approach. Such an approach requires close collaboration between disciplines such as neuroimaging, clinical psychiatry, MR-physics, statistics and exploratory data analysis, neuroscience, and psychological research . In light of this challenge, five research centers from the Medical University of Vienna and the University of Vienna joined forces in the research cluster MMI-CNS. Collaboration of these centers will secure the knowledge, expertise, and facilities required to achieve our main objectives. Establishing an infrastructure for multimodal research projects involving both universities is a prerequisite to allow for multimodal neuroimaging methods to progress from bench to bedside.
Given that each neuroscientific method has specific advantages and disadvantages, we propose that combining different methods in a multimodal approach can overcome these individual limitations, and yield more detailed insights into normal and abnormal brain function. Functional Magnetic Resonance Imaging (fMRI), for example, has enabled profound insights into human brain function by assessing cerebral activation with high spatial resolution. The relatively low temporal resolution, however, poses a specific disadvantage compared to other techniques such as electroencephalography (EEG). EEG provides information on neural processes with millisecond accuracy (but with a very low spatial resolution). Moreover, psychiatric disorders are not only associated with alterations in the central but also in the autonomic nervous system. Psychophysiological measurements of heart rate, skin conductance and electromyographic responses therefore will add valuable information in the quest for neurobiological markers, and so does tracking eye movements which provides direct information about possible alterations of fundamental attention processes.
While fMRI, EEG and psychophysiological measurements reveal correlations between mental phenomena and their underlying neural mechanisms, these methods are limited for drawing causal conclusions about the role of certain brain structures for a specific function or dysfunction. Therefore, these methods need to be complemented by methods such as transcranial magnetic stimulation (TMS) or transcranial direct-current stimulation (tDCS). By temporarily interfering with ongoing neural processing, these methods enable establishing mechanistic links between brain activity and mental phenomena.