Hallucinogens | Neuro-patch
A recent article in The Psychologist by Carhart, Kaelen and Nutt (here) reviews what is known about the action of chemicals that cause hallucinations: LSD from ergot fungi, dimethyltryptamine from ayahuasca and psilocybin from magic mushrooms. The molecular action of the hallucinogens is to excite particular pyramidal neurons by mimicking the action of the transmitter serotonin. These layer 5 pyramidal neurons are important for projecting to lower centers outside the cortex and within it. They mostly project to neurons that are inhibitory. The net effect is that the exciting of the pyramid cells creates an inhibitory signal from other neurons. It tends to generally shut things down. The oscillations in the cortex, so important to the workings of the brain, are decreased in strength and also desynchronized. The disruption of brain waves seems to stem from the interference with the pyramidal cells - inhibitory cell chains. This decrease in activity is especially evident in some very