Navegando por Autor "Falchi, Marcelo"
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Artigo Low-dose LSD and the stream of thought: Increased Discontinuity of Mind, Deep Thoughts and abstract flow(Springer Science and Business Media LLC, 2021-10-28) Wießner, Isabel; Falchi, Marcelo; Fontes, Fernanda Palhano Xavier de; Maia, Lucas Oliveira; Feilding, Amanda; Ribeiro, Sidarta Tollendal Gomes; Mota, Natália Bezerra; Araujo, Draulio Barros de; Tófoli, Luís FernandoRationale: Stream of thought describes the nature of the mind when it is freely roaming, a mental state that is continuous and highly dynamic as in mind-wandering or free association. Classic serotonergic psychedelics are known to profoundly impact perception, cognition and language, yet their influence on the stream of thought remains largely unexplored. Objective: To elucidate the effects of LSD on the stream of thought. Methods: In a randomized, double-blind, placebo-controlled, crossover study, 24 healthy participants received 50 μg lysergic acid diethylamide (LSD) or inactive placebo. Mind-wandering was measured by the Amsterdam Resting State Questionnaire (ARSQ), free association by the Forward Flow Task (FFT) for three seed word types (animals, objects, abstract words). ARSQ and FFT were assessed at +0 h, +2 h, +4 h, +6 h, +8 h and +24 h after drug administration, respectively. Results: LSD, compared to placebo, induced different facets of mind-wandering we conceptualized as “chaos” (Discontinuity of Mind, decreased Sleepiness, Planning, Thoughts under Control, Thoughts about Work and Thoughts about Past), “meaning” (Deep Thoughts, Not Sharing Thoughts) and “sensation” (Thoughts about Odours, Thoughts about Sounds). LSD increased the FFT for abstract words reflecting an “abstract flow” under free association. Overall, chaos was strongest pronounced (+2 h to +6 h), followed by meaning (+2 h to +4 h), sensation (+2 h) and abstract flow (+4 h). Conclusions: LSD affects the stream of thought within several levels (active, passive), facets (chaos, meaning, sensation, abstractness) and time points (from +2 h to +6 h). Increased chaos, meaning and abstract flow at +4 h indicate the utility of a late therapeutic window in psycholytic therapy.Artigo Nootropic effects of LSD: Behavioral, molecular and computational evidence(Elsevier BV, 2022-06-19) Ornelas, Isis M; Silva, Felipe Augusto Cini da; Wießner, Isabel; Marcos, Encarni; Araujo, Draulio Barros de; Goto-Silva, Livia; Nascimento, Juliana; Silva, Sérgio Ruschi Bergamachi; Costa, Marcelo N; Falchi, Marcelo; Olivieri, Rodolfo; Fontes, Fernanda Palhano Xavier de; Sequerra, Eduardo Bouth; Martins-de-Souza, Daniel; Feilding, Amanda; Costa, César Rennó; Tófoli, Luis Fernando; Rehen, Stevens K; Ribeiro, Sidarta Tollendal GomesThe therapeutic use of classical psychedelic substances such as d-lysergic acid diethylamide (LSD) surged in recent years. Studies in rodents suggest that these effects are produced by increased neural plasticity, including stimulation of the mTOR pathway, a key regulator of metabolism, plasticity, and aging. Could psychedelic-induced neural plasticity be harnessed to enhance cognition? Here we show that LSD treatment enhanced performance in a novel object recognition task in rats, and in a visuo-spatial memory task in humans. A proteomic analysis of human brain organoids showed that LSD affected metabolic pathways associated with neural plasticity, including mTOR. To gain insight into the relation of neural plasticity, aging and LSD-induced cognitive gains, we emulated the experiments in rats and humans with a neural network model of a cortico-hippocampal circuit. Using the baseline strength of plasticity as a proxy for age and assuming an increase in plasticity strength related to LSD dose, the simulations provided a good fit for the experimental data. Altogether, the results suggest that LSD has nootropic effects