Ketamine has multiple uses—as an anesthetic, a model of psychosis, and an antidepressant—but its physiology is complex because it acts on several sites at clinically relevant doses. This review examines ketamine's acute effects on the resting brain, moving from its pharmacology through in vitro and in vivo electrophysiology to EEG/MEG and neuroimaging studies (MRI and PET). The picture of ketamine's effects is complicated and sometimes confusing, likely due to differences in species, doses, and analytical methods. The authors suggest strategies for future research to address these issues.
A narrative review of early- to mid-20th-century research finds that psychedelic drugs alter perception across multiple sensory domains. Psychedelics influence all levels of the visual system, from retina to cortex, and can produce complex imagery and hallucinations. They also affect auditory discrimination and processing, sometimes leading to auditory hallucinations. The drugs distort body schema and time perception. Methodological limitations of that era temper the findings. The review preserves and synthesizes this pioneering work to guide future studies.