Pantomiming the use of tools is associated with activation of the left intraparietal cortex and dorsolateral frontal cortex. The left intraparietal cortex may store the representations of tool-use formulae, whereas the dorsolateral frontal cortex activation may reflect the switching between innervatory motor programs.

, FÁTIMA AZEVEDO IGNÁCIO 7 , ROGÉRIO PAYSANO MARROCOS 8 ABSTRACT -We tested the hypothesis that Part B of the Trail Making Test (TMT) is a measure of cognitive setshifting ability in 55 normal subjects with the conventional (written) TMT and a verbal adaptation, the "verbal TMT" (vTMT). The finding of a significant association between Parts B of TMT and vTMT (r = 0,59, p < 0,001), after correcting for age and education, supports the view that Part B of TMT is a valid measure of the ability to alternate between cognitive categories.KEY WORDS: trail making test, verbal trail making test, set-shifting cognition. . In Part A, the circles are numbered from 1 to 25, whereas in Part B numbers from 1 to 13 and letters from A to M must be connected in alternating fashion, beginning at 1-A and ending at M-13. Total score is given by time spent to complete each part. Factor analysis has shown that the TMT loads on both a rapid visual search and a visuospatial sequencing factor 3 . Whether it also superimposes on a third, "cognitive set-shifting", factor has been debated [4][5][6] . If true, however, this would be an important attribute of the test, as the ability to switch between categories is one of the most reliable indexes of normal neurobehavioral functioning 7 .In this study we administered a verbal adaptation of TMT-the "verbal Trail Making Test" (vTMT)-to normal individuals to see whether Part B of Trail Making Test (TMTB) also gauges the ability to shift between cognitive sets. Since in vTMT the visuospatial and visuomotor factors intrinsic to the conventional (written) TMT are reduced to a minimum, a lack of correlation between Parts B

RESUMO -O conceito de desempenho executivo se refere a uma coleção de habilidades cognitivas essenciais para a organização do funcionamento mental e comportamental. Investigamos o desempenho executivo de 61 adultos normais com dois testes padrão, o Teste de Wisconsin (TW) e a Torre de Londres (TL). Nosso propósito consistiu em testar as hipóteses de que (i) o desempenho executivo é constituído de dimensões múltiplas como ocorre, por exemplo, com a memória e a linguagem; (ii) o desempenho executivo de indivíduos normais está relacionado, ao menos em parte, com o sucesso ocupacional do indivíduo. A ausência de correlação estatística entre o TW e a TL indicou que o desempenho executivo constitui-se de fatores múltiplos, possivelmente estruturados sobre circuitos neurais em larga medida independentes. Em segundo, o desempenho dos homens foi superior ao das mulheres nos problemas mais exigentes (problemas com 4 e 5 ações mínimas) da TL. .inalmente, o grau de ajuste ocupacional se correlacionou significativamente com a parte difícil da TL. Estas verificações ajudam a explicar certas dissociações do comportamento executivo frequentemente observadas na clínica, sendo certas tarefas atingidas seletivamente. Indicam também que apenas certos módulos executivos se relacionam mais diretamente com a capacidade de ajuste à vida cotidiana. Se replicado, este achado poderá ser útil na previsão de sucesso em programas de reabilitação cognitiva. PALAVRAS-CHAVE: desempenho executivo, lobos frontais, Torre de Londres, Teste de Wisconsin.The neuropsychology of executive behavior: performance of normal individuals on the Tower of London and Wisconsin Card Sorting tests ABSTRACT -The concept of executive behavior encompasses a set of abilities which are critical for the organization of thought and behavior. To test the hypothesis that executive behavior is composed of multiple modules we investigated the performance of 61 normal adults on two widely used executive tasks, the Wisconsin Card Sorting (WCST) and the Tower of London (TOL) tests. We hypothesized that if executive behavior were composed of multiple modules, the main dimensions of each task would be weakly, if at all, statistically related. We also tested the hypothesis that occupational functioning would be related to executive performance. Our results revealed no significant association between the WCST and TOL tasks, favoring the idea that executive behavior is made up of multiple neuropsychological dimensions. Secondly, men fared significantly better than women on the difficult (4 and 5-moves) TOL puzzles. .inally, there was a significant association between performance on the difficult TOL puzzles and level of occupational functioning. These findings may explain certain dissociations in executive behavior commonly observed in patients with focal or diffuse brain damage. If replicated, they might be useful in the prediction of success in cognitive rehabilitation programs. A expressão desempenho executivo denota a capacidade de planejar, organizar e efetuar ações e comporta...

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