The cerebral cortex can be divided into distinct areas based on the density of proteins involved in the serotonin system. Using positron emission tomography in healthy participants, the study quantified serotonin 1A receptors (n = 30), 5-HT2A receptors (n = 22), the serotonin-degrading enzyme monoamine oxidase A (n = 32), and the serotonin transporter (n = 24). Clustering analysis identified five optimal clusters of cortical regions defined by these molecular profiles. These clusters explained the effects of psychotropic drugs acting on serotonin, such as antidepressants and psychedelics, suggesting the method is useful for integrating multimodal imaging data in neuropharmacology and psychiatry.
Oral ketamine may offer a more accessible alternative to intravenous and intranasal routes for treating depression, as it is easier to administer and has established safety and efficacy for chronic pain patients at home. The text suggests that current delivery methods limit ketamine's availability to specialized centers, but oral administration could expand access to antidepressant therapy.