CANNABIS AND THE BRAIN WITH SPECIAL REFERENCE TO THE LIMBIC SYSTEM

Abstract

An hypothesis is presented which suggests that the cognitive, subjective-emotional and perceptual changes produced by psychoactive cannabinoids may be mediated in part by actions of these agents on limbic system structures and limbic cortical connections. The major cognitive alterations which are found following cannabinoid intoxication are impaired memory functioning, lapses in attention, altered speech production and general problems with complex information processing. Perceptual anomalies consist of alterations in time perception with moderate doses, and visual distortions and hallucinations with high doses of cannabinoids. Subjective-emotional changes reported following cannabinoid intoxication include feelings of euphoria, drowsiness, a sensation of well being with low to moderate doses and feelings of derealization and depersonalization with higher doses. The role of the limbic system structures such as septum, hippocampus, amygdala and hypothalamus in the mediation of these cannabinoid effects along with feedback loops running between limbic structures, thalamus and frontal and temporal cortices was reviewed and analyzed.