title: Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide.
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.
authors.affiliation: Department of Psychology, School of Social Sciences, University of Dundee, Dundee, UK j.speth@dundee.ac.uk.
authors.forename: Jana
authors.initials: J
authors.lastname: Speth
authors.affiliation: Department of Psychology, School of Social Sciences, University of Dundee, Dundee, UK.
authors.forename: Clemens
authors.initials: C
authors.lastname: Speth
authors.affiliation: Centre for Neuropsychopharmacology, Imperial College London, London, UK.
authors.forename: Mendel
authors.initials: M
authors.lastname: Kaelen
authors.affiliation: Department of Psychology, School of Social Sciences, University of Dundee, Dundee, UK.
authors.forename: Astrid M
authors.initials: AM
authors.lastname: Schloerscheidt
authors.affiliation: Beckley Foundation, Oxford, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Feilding
authors.affiliation: Centre for Neuropsychopharmacology, Imperial College London, London, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Nutt
authors.affiliation: Centre for Neuropsychopharmacology, Imperial College London, London, UK.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Carhart-Harris
mesh_terms: D061605:Administration, Intravenous / Q000379:methods; D000328:Adult; D001921:Brain / Q000187:drug effects*; D001931:Brain Mapping / Q000379:methods; D018592:Cross-Over Studies; D005260:Female; D006213:Hallucinogens / Q000008:administration & dosage*; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008238:Lysergic Acid Diethylamide / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008568:Memory / Q000187:drug effects; D011939:Mental Recall / Q000187:drug effects*; D008875:Middle Aged; D009434:Neural Pathways / Q000187:drug effects*; D055815:Young Adult
chemical_list: D006213:Hallucinogens; D008238:Lysergic Acid Diethylamide
keywords: Altered states of consciousness; default-mode network; episodic past memory; lysergic acid diethylamide; mental time travel; mentation reports; psychedelics; self