A peculiar feature of the mammalian hippocampus is that it maintains the ability to generate new neurons throughout adult life while most other areas of the brain do not. In this book, we outline evidence for the functional consequences of adult neurogenesis in the dentate gyrus highlighting a possible role in learning and memory and depression. Presynaptic modulation at the MF synapse is also described with respect to its involvement in the activity-dependent nature of the MF synapse and contribution to physiological functions of MFs. In addition, the hippocampus is one of the first and most affected brain regions impacted by both Alzheimer's disease and mild cognitive impairment. This book discusses such negative consequences of aging and diseases which may be prevented or reversed by physical exercise, which has been associated with improved hippocampul-dependent learning and memory and executive functioning. The functional status of hippocampal cholinergic terminals was also assessed in order to determine if an early beginning of ethanol consumption at moderate doses disrupts acetylcholine release in animals non selected by ethanol preference.