The ability to efficiently store memory in brain is a fundamental process needed for daily functions and its impairment is associated with human mental disorders. The formation of long-term memory (LTM) is believed to involve alterations of synaptic efficacy within selected synapses which are mediated by changes in synaptic transmission and alterations in synaptic contacts. We study the cellular and molecular mechanisms that underlie memory formation, storage and retrieval. Toward these ends we use the classical fear conditioning paradigm, which is a simple form of associative learning. Fear conditioning is a useful behavioral assay for studying the cellular and molecular basis of learning and memory because the brain area underlying fear memory formation, the lateral nucleus of the amygdala (LA), has been identified. In addition, the acquisition of fear conditioning is fast and its memory is robust and long lasting, properties which facilitate the correlation of cellular events in LA with phases of learning, consolidation and retrieval. By employing multidisciplinary approaches which include behavioral, molecular (e.g. genomics and proteomics), electrophysiological, and anatomical (e.g. confocal microscopy) techniques we study cellular and molecular processes in LA underlying fear memory formation and retrieval. Using the above approaches we investigate the roles of signal transmission between neurons, changes in neuronal connectivity and morphology, signal transduction and gene expression in fear memory formation and synaptic plasticity in LA.