A Neural Model of Memory Impairment in Diffuse Cerebral Atrophy

• Published in: British journal of psychiatry 1995-01, Vol.166 (1), p.19-28
• Main Authors: Ruppin, Eytan, Reggia, James A.
• Format: Article
• Language: English
• Subjects: Aged; Alzheimer Disease - physiopathology; Alzheimer Disease - psychology; Alzheimer's disease; Anatomy; Associative memory; Atrophy; Brain - pathology; Brain - physiopathology; Brain Damage, Chronic - physiopathology; Brain Damage, Chronic - psychology; Computational neuroscience; Degradation; Deterioration; Humans; Memories; Memory; Memory - physiology; Memory disorders; Mental Recall - physiology; Nerve Degeneration - physiology; Neural network models; Neural networks; Neural Networks (Computer); Neurodegenerative diseases; Neurons; Neurons - physiology; Patients; Retention (Psychology) - physiology; Synapses - physiology
• ISSN: 0007-1250; 1472-1465
• DOI: 10.1192/bjp.166.1.19

Computer-supported neural network models have been subjected to diffuse, progressive deletion of synapses/neurons, to show that modelling cerebral neuropathological changes can predict the pattern of memory degradation in diffuse degenerative processes such as Alzheimer's disease. However, it has been suggested that neural models cannot account for more detailed aspects of memory impairment, such as the relative sparing of remote versus recent memories. The latter claim is examined from a computational perspective, using a neural associative memory model. The neural network model not only demonstrates progressive memory deterioration as diffuse network damage occurs, but also exhibits differential sparing of remote versus recent memories. Our results show that neural models can account for a large variety of experimental phenomena characterising memory degradation in Alzheimer's patients. Specific testable predictions are generated concerning the relation between the neuraonatomical findings and the clinical manifestations of Alzheimer's disease.