The results of recent publications on a role of stem cells in the processes of neurogenesis, adaptation and neuroplasticity are summarized. An aim of the paper was to present evidence for a possibility of development and regeneration of cellular elements in the adult brain in normality and pathology. The latter was driven by the discussion of the studies on Alzheimer's disease, Parkinson's disease, schizophrenia and affective disorders. Pharmacological effects on the neurogenesis and perspectives of this research are reviewed.