Drug Treatment Memory Dysfunction

Memory deficits in the adult can develop from lesions that disrupt circuits that interconnect structures involved in encoding and retrieving recently acquired information, as well as from those involved in transferring information to long-term storage. The most important structure of this memory system is the hippocampalentorhinal complex. Other areas involved in memory processes include the amygdala, paralimbic cortices, thalamic nuclei, mammillary bodies, fornix, hypothalamic nuclei, basal forebrain, and ventral striatum. Therefore, amnestic, or memory, disorders can occur from lesions at any part of this system and have a wide variety of causes, including infections, exposure to toxic substances, medications, vitamin deficiency, head trauma, cerebrovascular disease, tumors, and some neurodegenerative disorders. However, the most frequent cause of amnestic disorders in the adult is Alzheimer's disease (AD). Indeed, focal memory deficits precede the development of dementia, and episodic memory deficits (i.e., inability to recall recent events) and semantic memory deficits (i.e., loss of factual knowledge and object recognition) are the hallmark characteristics of the AD dementia syndrome, with episodic memory deficits preceding semantic memory deficits. AD has been reported in up to 10 percent of the population age sixty-five or older, and it is estimated that by the year 2040, 14 million Americans will have AD. Therefore, there is a significant effort to develop medications that can treat or ameliorate AD symptoms.