Amnestic disorders and their role in cognitive theory.

Amnesia refers to a disorder of memory, and classical amnesia with continuous problems in acquiring new information is the most studied type of amnesia. The integration into a memory systems model of clinical studies of classical amnesia, cognitive theory, and studies with neuroimaging methods is one of the prime success stories in modern cognitive neuroscience. The clinical spectrum of amnesia encompasses a wide range of disorders ranging from specific encoding deficits for language or visuospatial information to psychogenic amnesia with confusion and loss of memory for personal identity. Two cases are reviewed, one with selective verbal amnesia and the other with focal retrograde amnesia, presenting some puzzles and challenges to current modular thinking about memory that may lead to theoretical advances. An interactive model emphasizing the communication between brain codes and regions in memory may have promise.