Central Nervous System: The brain and spinal cord.
Cerebral cortex: The region of the brain responsible for cognitive functions including reasoning, mood, and perception of stimuli.
Dissociative: a type of compound, such as phencyclidine or ketamine, that produces an anesthetic effect characterized by a feeling of being detached from the physical self.
DXM: A common street name for dextromethorphan.
Flashback: A sudden but temporary recurrence of aspects of a drug experience (including sights, sounds, and feelings) that may occur days, weeks, or even more than a year after hallucinogenic drug use.
Glutamate: An excitatory neurotransmitter found throughout the brain that influences the reward system and is involved in learning and memory, among other functions.
Hallucinogen: A drug that produces hallucinations—distortions in perception of sights and sounds—and disturbances in emotion, judgment, and memory.
HPPD: Hallucinogen persisting perception disorder; the spontaneous and sometimes continuous recurrence of perceptual effects of LSD long after an individual has ingested the drug.
Kappa opioid receptor: A receptor on nerve cells that is activated by certain opioid-like compounds produced in the body. These receptors differ from those activated by the more commonly known opioids, such as heroin and morphine.
Neurotransmitter: A chemical compound that acts as a messenger to carry signals from one nerve cell to another.
NMDA receptors: N-methyl-D-aspartate receptors, a type of glutamate receptor that is important for learning and memory; it is the target of drugs such as PCP and ketamine.
Persistent psychosis: Unpredictable and long-lasting visual disturbances, dramatic mood swings, and hallucinations experienced by some LSD users after they have discontinued use of the drug.
Serotonin: A neurotransmitter involved in a broad range of effects on perception, movement, and emotions. Serotonin and its receptors are the targets of most hallucinogens.