ABSTRACT
Memory, the faculty by which the mind stores and remembers information, is not monolithic, but is composed of subsystems that process specific types of information. In this chapter, definitions, neurological substrates, functions and organization of the memory system are described. Clinical and experimental studies assign to the hippocampus a major anatomical role in memory functions. This region can be considered the most active brain region for neural plasticity. Neurogenesis is present only in the hippocampus and adjacent regions, while the most-studied model of functional neural plasticity, long term potentiation, and its opposite process, long term depression, were first identified in the hippocampus. Different factors can influence the memory process, both at structural and functional levels. Aging, for example, has a deleterious effect on short term and episodic memory, while semantic memory is unaffected. Sleep deprivation reduces learning, affecting the hippocampal activity during the encoding and consolidation processes. In chronic insomnia, regressive structural changes in the hippocampus have been recorded.
