Resumo

Rationale. Attention and executive functions are cognitive domains usually described in the literature as associated processes and they are also related to modulation of the cholinergic system. However, how these domains interact, especially as regards of fractionation of executive functions, has been largely ignored. Objectives. Using acute doses of donepezil we evaluated the relations between the cholinergic modulation of sustained attention and 6 different measures of executive function associated to theoretically independent executive domains, namely shifting, updating, inhibition, planning, access to long term memory and dual task performance. Methods. This was a double-blind, placebo controlled, independent groups design study including 42 healthy, young volunteers. Subjects were randomly assigned to one of three treatments: placebo and donepezil (5 mg p. o. and 7, 5 mg p. o.). The test battery included the sustained attention measure, the Psychomotor Vigilance Test (PVT), and measures of 6 different subtypes of executive functions. Results. Donepezil improved visuomotor performance (Placebo: 186ms±14, Donepezil 5mg: 175ms±21, Donepezil 7.5mg:163ms±21), sustained attention (Placebo: -6.61±11.80 , Donepezil 5mg: -1.65±11.22, Donepezil 7.5mg: 5.83±9.80) and dual task performance (Placebo: 87.71±12.40, Donepezil 5mg: 93.68±8.19, Donepezil 7.5mg: 97.90±10.42), however the attention measures did not correlate with executive functions. The others executive domains evaluated did not present any differences between groups. Conclusion. Donepezil improved attention and executive functions, however only dual-task performance was sensitive to this cholinergic manipulation. This suggests a pharmacological indication of the diversity of executive functions. Furthermore, the improvements in attention and in executive functions were not related, suggesting that these results do not reflect the same pharmacological effects.