Neuroimaging studies of fronto-limbic dysfunction in geriatric depression

Geriatric depression (GD) is an increasingly prevalent condition with specific clinical features and comorbidities. The neurobiology of this condition has only recently begun to be elucidated. The structural and functional neuroimaging literature relevant to a systems-level neurobiological understanding of GD is reviewed. A positron emission tomography (PET) imaging activation study of GD is described. This study utilized neurocognitive activation probes, as well as resting measures, to examine fronto-limbic abnormalities associated with clinical features, neuropsychological profiles, and treatment outcome in GD. Such ongoing work helps to establish models and test hypotheses concerning the neural substrates and pathophysiology of this devastating neuropsychiatric condition. In so doing, it provides a foundation for the development of more specific, biologically-based diagnostic and treatment strategies.