Identification of neural targets for the treatment of psychiatric disorders: the role of functional neuroimaging

Brain donation at autopsy: clinical characterization and toxicologic analyses

The study of postmortem human brain tissue is central to the advancement of neurobiologic studies of psychiatric and neurologic illnesses, particularly the study of brain-specific isoforms and molecules. Due to tissue demands, especially pertaining to brain regions strongly implicated in the pathophysiology of neuropsychiatric disorders, the success and future of this research depend on the availability of high-quality brain specimens from large numbers of subjects, including nonpsychiatric controls, both of which may be obtained from brain banks. In this chapter, we elaborate on the need for and acquisition of well-curated and properly diagnosed postmortem human brains, relying upon our experience with the Human Brain and Tissue Repository located at the Lieber Institute for Brain Development in Baltimore, MD. We explain the advantages of sourcing postmortem human tissue from medical examiner offices, which provide access to cases of all ages, both with and without central nervous system disorders. Neuropathology analyses and toxicologic screenings, along with autopsy reports and extensive interviews with family members and treating physicians, are invaluable to the diagnoses of postmortem cases. Ultimately, the study of psychiatric and neurologic disorders is the study of brain disease, and accordingly, there is no substitution for human brain tissue.

The neurobiology of depression and antidepressant action

We present a comprehensive overview of the neurobiology of unipolar major depression and antidepressant drug action, integrating data from affective neuroscience, neuro- and psychopharmacology, neuroendocrinology, neuroanatomy, and molecular biology. We suggest that the problem of depression comprises three sub-problems: first episodes in people with low vulnerability ('simple' depressions), which are strongly stress-dependent; an increase in vulnerability and autonomy from stress that develops over episodes of depression (kindling); and factors that confer vulnerability to a first episode (a depressive diathesis). We describe key processes in the onset of a 'simple' depression and show that kindling and depressive diatheses reproduce many of the neurobiological features of depression. We also review the neurobiological mechanisms of antidepressant drug action, and show that resistance to antidepressant treatment is associated with genetic and other factors that are largely similar to those implicated in vulnerability to depression. We discuss the implications of these conclusions for the understanding and treatment of depression, and make some strategic recommendations for future research.

Clinical applications and future directions of functional MRI

First described for use in mapping the human visual cortex in 1991, functional magnetic resonance imaging (fMRI) is based on blood-oxygen level dependent (BOLD) changes in cortical regions that occur during specific tasks. Typically, an overabundance of oxygenated (arterial) blood is supplied during activation of brain areas. Consequently, the venous outflow from the activated areas contains a higher concentration of oxyhemoglobin, which changes the paramagnetic properties of the tissue that can be detected during a T2-star acquisition. fMRI data can be acquired in response to specific tasks or in the resting state. fMRI has been widely applied to studying physiologic and pathophysiologic diseases of the brain. This review will discuss the most common current clinical applications of fMRI as well as emerging directions.

Somatic treatments for mood disorders

Somatic treatments for mood disorders represent a class of interventions available either as a stand-alone option, or in combination with psychopharmacology and/or psychotherapy. Here, we review the currently available techniques, including those already in clinical use and those still under research. Techniques are grouped into the following categories: (1) seizure therapies, including electroconvulsive therapy and magnetic seizure therapy, (2) noninvasive techniques, including repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and cranial electric stimulation, (3) surgical approaches, including vagus nerve stimulation, epidural electrical stimulation, and deep brain stimulation, and (4) technologies on the horizon. Additionally, we discuss novel approaches to the optimization of each treatment, and new techniques that are under active investigation.