Challenging the classical distinction between long-term and short-term memory: reconsidering the role of the hippocampus

摘要

The hippocampus and surrounding medial temporal lobe structures have long been held to be critical for long-term declarative memory, but not for short-term or working memory. In fact the notion that patients with selective and bilateral medial temporal lobe lesions have intact short-term memory has been a key argument to support the classical distinction between long- and short-term memory. However, recent behavioral, neuroimaging and electrophysiological data collected in humans have begun to challenge this classical distinction. Converging evidence now suggests that the ability to maintain the configural relationships of visual information in working memory for periods as short as a few seconds critically depends on the hippocampus. In functional terms, the hippocampus may be necessary for coordinating short-term maintenance when it relies on distributed cortical representations of objects, locations and their conjunctions. These findings indicate a need for modifying the current diagnostic work-up of patients with hippocampal lesions and the neuropsychological criteria for hippocampal dysfunction, which are currently centered upon the theory that hippocampal lesions will primarily affect long-term memory.