Randomized clinical trials, which involve giving some participants a drug, others a placebo, and comparing the effects of both, are considered the gold standard in such studies. But such trials are slow and expensive, and tend to involve only a small number of participants. "[It takes] multiple years, costs a seven-digit amount of money, [and] the ethics approvals take forever," says Bzdok. Instead, his team used natural language processing to assess 6,850 written accounts of hallucinogenic drug use. Each account was written by a person who took one of 27 drugs--including ketamine, MDMA, LSD and psilocin--in a real-world setting rather than as part of a lab-based experiment.

The terminology humans have conceived to explain and study our own brain may be mis-aligned with how these constructs are actually represented in nature. For example, in many human societies, when a baby is born either a "male" or a "female" box is checked on the birth certificate. Reality, however, may be less black and white. In fact, the assumption of dichotomic differences between only two sex/gender categories may be at odds with our endeavors that try to carve nature at its joints. Such is the case with a new paper, published recently in the journal Cerebral Cortex, where researchers argue that there are at least nine directions of brain-gender variation.