CHOLINERGIC SUBSTRATES OF COGNITION AND ORGANISM-ENVIRONMENT INTERACTION

1. Several lines of evidence support the notion of cholinergicity of c ognition and organism-environment interaction: a) Certain central path ways which were amply demonstrated as cholinergic in nature were also shown as significant for cognition and related processes; this is indi cated by lesion experiments in animals and related evidence collected in man which includes that obtained in SDAT. b) Cholinergic agonists e voke a specific EEG alerting and hippocampal theta patterns that were shown to be the EEG counterparts of learning. c) The REM sleep reflect s significant cholinergic correlates, and this phenomenology relates t o the EEG components of cognition. d) Cholinergic agonists facilitate and cholinergic antagonists disrupt animal learning; in fact, benefici al effects were obtained with cholinergic agonists in animal models sp ecifically designed to reflect impaired animal-environment interaction . e) Trophic factors restore cognition in lesioned animals and may exh ibit similar action in human subjects suffering from cholinergic defic it. 2. While many of these effects show that the cholinergic phenomena underlie cognitive facilitation and specific alerting, certain depres sive symptoms are evoked in man and animals by muscarinic agonists. 3. Altogether, it is speculated that, overall the central cholinergic fu nction in awaken man and animals represents a cholinergic syndrome whi ch relates to REM sleep and which exhibits a number of characteristic EEG, functional and behavioral phenomena. This syndrome is referred to as CANMB and its normal function underlies appropriate animal-organis m interaction.