Ketamine reduces the neural distinction between self- and other-produced affective touch: a randomized double-blind placebo-controlled study.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology October 1, 2024 Reinoud Kaldewaij, Paula C Salamone, Adam Enmalm et al. 19 citations
Ketamine, a drug that temporarily disrupts the sense of self, reduces the brain's ability to distinguish between one's own touch and touch from another person. In a double-blind, placebo-controlled crossover study, 30 healthy adults received intravenous ketamine or placebo while undergoing functional MRI. Ketamine weakened neural activity in the right temporoparietal cortex, a region involved in touch perception and social cognition, especially when participants were touched by someone else. This reduction correlated with decreased interoceptive awareness. Ketamine also increased connectivity between the temporoparietal cortex and somatosensory cortex and insula during other-touch, which correlated with the strength of dissociation. The findings suggest ketamine disrupts self-other-differentiation by altering top-down signaling, making predictable self-generated and unpredictable other-generated touch more similar.