LSD acutely impairs working memory, executive functions, and cognitive flexibility, but not risk-based decision-making
PSYCHOLOGICAL MEDICINE
Authors: Pokorny, Thomas; Duerler, Patricia; Seifritz, Erich; Vollenweider, Franz X.; Preller, Katrin H.
Abstract
Background Psychiatric and neurodegenerative illnesses are characterized by cognitive impairments, in particular deficits in working memory, decision-making, and executive functions including cognitive flexibility. However, the neuropharmacology of these cognitive functions is poorly understood. The serotonin (5-HT) 2A receptor might be a promising candidate for the modulation of cognitive processes. However, pharmacological studies investigating the role of this receptor system in humans are rare. Recent evidence demonstrates that the effects of Lysergic acid diethylamide (LSD) are mediated via agonistic action at the 5-HT(2A)receptor. Yet, the effects of LSD on specific cognitive domains using standardized neuropsychological test have not been studied. Methods We examined the acute effects of LSD (100 mu g) alone and in combination with the 5-HT(2A)antagonist ketanserin (40 mg) on cognition, employing a double-blind, randomized, placebo-controlled, within-subject design in 25 healthy participants. Executive functions, cognitive flexibility, spatial working memory, and risk-based decision-making were examined by the Intra/Extra-Dimensional shift task (IED), Spatial Working Memory task (SWM), and Cambridge Gambling Task (CGT) of the Cambridge Neuropsychological Test Automated Battery. Results Compared to placebo, LSD significantly impaired executive functions, cognitive flexibility, and working memory on the IED and SWM, but did not influence the quality of decision-making and risk taking on the CGT. Pretreatment with the 5-HT(2A)antagonist ketanserin normalized all LSD-induced cognitive deficits. Conclusions The present findings highlight the role of the 5-HT(2A)receptor system in executive functions and working memory and suggest that specific 5-HT(2A)antagonists may be relevant for improving cognitive dysfunctions in psychiatric disorders.
Micromolar Valproic Acid Doses Preserve Survival and Induce Molecular Alterations in Neurodevelopmental Genes in Two Strains of Zebrafish Larvae
BIOMOLECULES
Authors: Messina, Andrea; Boiti, Alessandra; Sovrano, Valeria Anna; Sgado, Paola
Abstract
Autism spectrum disorders (ASDs) comprise a genetically heterogeneous group of conditions characterized by a multifaceted range of impairments and multifactorial etiology. Epidemiological studies have identified valproic acid (VPA), an anticonvulsant used to treat epilepsy, as an environmental factor for ASDs. Based on these observations, studies using embryonic exposure to VPA have been conducted in many vertebrate species to model ASD. The zebrafish is emerging as a popular model in biomedical research to study the molecular pathways involved in nervous system disorders. VPA exposure in zebrafish larvae has been shown to produce a plethora of effects on social, motor and anxiety behavior, and several genetic pathways altered by VPA have been described. However, the doses and regimen of administration reported in the literature are very heterogenous, creating contradictory results and posing serious limits to the interpretation of VPA action on neurodevelopment. To shed light on the toxic effect of VPA, we tested micromolar concentrations of VPA, using exposure for 24 and 48 h in two different zebrafish strains. Our results show that micromolar doses of VPA mildly affect embryo survival but are sufficient to induce molecular alterations in neurodevelopmental genes previously shown to be influenced by VPA, with substantial differences between strains.