What is the evidence for impairments of cellular plasticity and resilience in severe mood disorders? Structural imaging studies have demonstrated reduced gray matter volumes in areas of the orbital and medial prefrontal cortex (PFC), ventral striatum, and hippocampus, and enlargement of third ventricle in mooddisordered patients

relative to healthy control Inhibitors,research,lifescience,medical samples.3,9,10 Postmortem neuropathological studies have shown abnormal reductions in glial cell counts/density, neuron size/density, and cortical volume/Selleckchem AZD5363 thickness in the subgenual PFC, orbital cortex, dorsal anterolateral PFC, amygdala, and in basal ganglia and dorsal raphe nuclei and hippocampus.11-16 Morphometric studies also have reported layer-specific reductions Inhibitors,research,lifescience,medical in intern eurons in the anterior cingulate cortex (ACC), and reductions in nonpyramidal neurons (~ 40% lower) in CA2 of the hippocampal

formation in bipolar disorder subjects compared with controls.17 Overall, the layer-specific cellular changes observed in several distinct brain regions, including the PFC, ACC, Inhibitors,research,lifescience,medical and hippocampus suggest that multiple neuronal circuits underlie the neuropathology of mood disorders. This is not altogether surprising since the behavioral and physiological manifestations of the illnesses are complex and include cognitive, affective, motoric, and neurovegetative symptomatology, as well as alterations of circadian rhythms and neuroendocrine systems, and arc thus undoubtedly mediated by networks of interconnected neurotransmitter systems

and neural circuits.13 In addition to the accumulating neuroimaging evidence, several postmortem brain studies are now providing Inhibitors,research,lifescience,medical direct evidence for reductions in regional CNS volume, cell number, and cell body size. Baumann and associates18 reported reduced volumes of the left nucleus accumbens, the right putamen, and bilateral pallidum externum in postmortem brain samples obtained from patients Inhibitors,research,lifescience,medical with unipolar depression or bipolar depression. The abnormal presence of white matter hyperintensities (WMH) has been reported in multiple magnetic resonance imaging (MRI) studies of geriatric patients with affective disorder, particularly those with late-onset depression (ie, elderly depressed patients who experience their first depression after age 60). Elderly adults (>60 years old) with severe WMH are before 3 to 5 times more likely to have depressive symptoms as compared with persons with only mild or no white matter lesions.19 Tupler and colleagues20 reported that late-onset depressed patients had more severe hyperintensity ratings in deep white matter than early-onset patients and controls, and that late- and early-onset patients had more severe subcortical gray matter hyperintensities (particularly in the putamen) compared with controls.