The hippocampus and its role in memory : Clinical manifestations and theoretical considerations

Abstract

Using as the basis for discussion a case report of a patient who had developed severe memory impairment without other evidence of neurologic involvement following barbiturate and nitrous oxide anesthesia, and who was found to have bilateral infarcts involving the hippocampi and neighboring structures, the relationship of the hippocampus to memory is discussed. There have been a few other similar cases reported. Memory loss often follows bilateral temporal lobectomy, and even unilateral temporal lobectomy if section includes portions of the uncus, parahippocampal gyrus and hippocampus. Stimulation of the hippocampus also causes disturbances of memory. While there is no memory "center", and lesions of various portions of the nervous system may affect memory, the hippocampi appear to be crucial for certain memory functions, and small lesions in them may cause profound disturbances of memory and learning.