Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide
Journal of Psychopharmacology – January 01, 2016
Source: CORE
Summary
A fascinating insight reveals how a specific compound can quiet the mind's tendency to dwell on the past. Volunteers received the compound or placebo in a controlled setting. Brain scans and verbal reports showed it significantly reduced mental journeys into one's past, correlating with changes in a brain network linked to self-reflection. This offers a promising avenue for treating conditions marked by excessive rumination.
Abstract
This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 μg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured interviews performed shortly after the functional magnetic resonance imaging (fMRI) scans (approximately 2.5 h post-administration). Within each report, specific linguistic references to mental spaces for the past, present and future were identified. Results revealed significantly fewer mental spaces for the past under LSD and this effect correlated with the general intensity of the drug’s subjective effects. No differences in the number of mental spaces for the present or future were observed. Consistent with the previously proposed role of the default-mode network (DMN) in autobiographical memory recollection and ruminative thought, decreased resting-state functional connectivity (RSFC) within the DMN correlated with decreased mental time travel to the past. These results are discussed in relation to potential therapeutic applications of LSD and related psychedelics, e.g. in the treatment of depression, for which excessive reflection on one’s past, likely mediated by DMN functioning, is symptomatic