Mental malfunction and memory maintenance mechanisms.

Abstract

Dreams appear to be generated in the process of reinforcing memory circuits of the brain, as circuits are activated by self-generated electrical slow waves, with dream contents reflecting information stored in activated circuits. Illusory dreams and other healthy delirious states appear to occur when activated memory circuits are incompetent, containing synapses whose efficacies deviate from their 'dedicated' values. Organic delirium and some other mental disorders may have their basis in brain pathologies that alter reinforcing slow waves, causing synaptic efficacies to depart from dedicated values. Activation of these incompetent circuits leads to recall of faulty memories--a substrate for delirium. In treatment of organic delirium by electroconvulsive therapy (ECT), the electric shock temporarily suppresses abnormal slow-wave regimes, allowing remedial reinforcement regimes to resume. These restore dedicated synaptic efficacies, temporarily alleviating the delirium. The action of ECT shocks appears to parallel closely that of cardiac defibrillating shocks. Greater than normal amounts of circuit reinforcement protect sensory circuitry in fatal familial insomnia, and cognitive circuitry in encephalitis lethargica.