Henry Gustav Molaison (1926-2008) was perhaps the best-known and most studied patient in the history of neuroscience. Henry became the subject of a scientific article which would become one of the most cited articles in the history of medical literature.
Psilocybin, a naturally occurring hallucinogen, is the main psychoactive component of psilocybe and other hallucinogenic mushrooms (so called “magic mushrooms”). Like other classic hallucinogens, such as d-lysergic acid diethylamide (LSD) and mescaline, psilocybin exerts its psychoactive effects through a sub-type of serotonin receptors (called 5-HT2a) in the brain. In some cultures, psilocybin has historically been used in religious contexts -- likely for millennia. Psilocybin has a number of effects, including changes in perception, cognition, affect, and decision-making. Clinical research on psilocybin dates back to at least the 1950s, with variable effects on the perceived affective character of the experience. Research on psilocybin administration in humans has occurred in psychotherapeutic contexts in terminally ill cancer patients dating back to the 1970s and continues today. A surprising new study reveals that, under specific conditions, acute exposure to psilocybin can elicit long-lasting positive changes and increases in mystical-type experience.
Social neuroscience is a rapidly growing discipline that examines the relationship between the brain and social behavior. The “social brain hypothesis” posits that, over evolutionary time, living in large, social groups favored the physical growth of brain regions important for social behavior. In non-human primates, some evidence indicates that the size of the amygdala is related to social behavior. Little is known, however, about this relationship in humans. A provocative new study finds that the volume of a key component of the social brain, the amygdala, is directly related to the size and complexity of social networks in adult humans.
Humans experience pleasure from a variety of stimuli, including food, money, and psychoactive drugs. Such pleasures are largely made possible by a brain chemical called dopamine, which activates what is known as the mesolimbic system -- a network of interconnected brain regions that mediate reward. Most often, rewarding stimuli are biologically necessary for survival (such as food), can directly stimulate activity of the mesolimbic system (such as some psychoactive drugs), or are tangible items (such as money). However, humans can experience pleasure from more abstract stimuli, such as art or music, which do not fit into any of these categories.