Effects of lorazepam on deductive reasoning

Rationale Benzodiazepines slow reasoning performance, but it is still unknown which phase of reasoning is affected and whether this effect is present for different types of relations between entities in reasoning problems.Objectives We investigated which phases of deductive reasoning are affected by lorazepam and whether this effect varies according to the type of relations in deductive reasoning problems.Methods This was a double-blind, crossover design study of acute oral doses of lorazepam (2 mg) and placebo, using young healthy volunteers. We focused on response delay of three separable phases of deductive reasoning and matched working memory tasks (that involved only maintenance of information) the premise processing phase, the premise integration phase, and the validation phase, in which reasoners decide whether a conclusion logically follows from the premises (reasoning task) or is identical to one of the premises (maintenance task). Type of relations in the premises was also manipulated. We employed material that was difficult to envisage visually and visuospatially (subiconic) and material easy to envisage visually or visuospatially.Results Lorazepam slowed response as memory load increased, irrespective of type of relations. It also specifically slowed validation in reasoning problems with visual relations, an effect that disappeared after subtraction of maintenance scores, and increased validation time in problems with subiconic relations, which remained after this subtraction.Conclusion Acute lorazepam administration affected reasoning in two ways: it slowed processing nonspecifically when working memory demands increased and augmented validation time depending on the difficulty in generating and/or manipulating mental representations by the central executive.Universidade Federal de São Paulo, Dept Neurol, Setor Eletrofisiol Clin, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol, Setor Eletrofisiol Clin, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilWeb of Scienc

Acute effects of donepezil in healthy young adults underline the fractionation of executive functioning

The cholinergic system is involved in the modulation of both bottom-up and top-down attentional control. Top-down attention engages multiple executive control processes, but few studies have investigated whether all or selective elements of executive functions are modulated by the cholinergic system. To investigate the acute effects of the pro-cholinergic donepezil in young, healthy volunteers on distinct components of executive functions we conducted a double-blind, placebo-controlled, independent-groups design study including 42 young healthy male participants who were randomly assigned to one of three oral treatments: glucose (placebo), donepezil 5 mg or donepezil 7.5 mg. the test battery included measures of different executive components (shifting, updating, inhibition, dual-task performance, planning, access to long-term memory), tasks that evaluated arousal/vigilance/visuomotor performance, as well as functioning of working memory subsidiary systems. Donepezil improved sustained attention, reaction times, dual-task performance and the executive component of digit span. the positive effects in these executive tasks did not correlate with arousal/visuomotor/vigilance measures. Among the various executive domains investigated donepezil selectively increased dual-task performance in a manner that could not be ascribed to improvement in arousal/vigilance/visuomotor performance nor working memory slave systems. Other executive tasks that rely heavily on visuospatial processing may also be modulated by the cholinergic system.Associacao Fundo de Incentivo a Psicofarmacologia (AFIP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniv Sussex, Dept Psychol, Sch Life Sci, Falmer, E Sussex, EnglandUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilFAPESP: 1998/14303-3Web of Scienc