Declarative Memory System: Amnesia

Abstract

Significant information about how memory is organized has come from the study of patients with memory disorders (amnesia). Amnesia refers to difficulty in acquiring new declarative (conscious) knowledge and in remembering the recent past. This condition results from bilateral damage to the medial temporal lobe or the diencephalic midline. Declarative memory impairment can occur as a well-circumscribed disorder against a background of otherwise intact intellectual and cognitive functions. Older memories that have undergone a process of consolidation and reorganization are usually intact in amnesic patients and are stored in the neocortex independently of the medial temporal lobe. Amnesic patients retain the ability to learn nondeclaratively (unconsciously), as in the case of habits and skills for which memory is expressed through performance rather than remembrance.