RESUMEN
We investigated the effect of transient dopamine depletion on functional connectivity during performance of the Wisconsin Card Sorting Task. Functional magnetic resonance imaging data were analyzed as a psychophysiological interaction, a statistical method used to identify functional connectivity during experimental manipulations. Nineteen healthy subjects were scanned, double blind, on 2 separate days: once after drinking an amino acid mixture deficient in the dopamine precursors tyrosine and phenylalanine, and once after drinking a nutritionally balanced mixture. In the balanced drink session, statistically significant connectivity between the frontal lobes and striatum was observed during set shifting, and the greater the prefrontostriatal connectivity, the faster the response time after a shift. Neither of these associations were observed after dopamine depletion. Moreover, dopamine depletion also reduced the degree of deactivation in areas normally suppressed during attention-demanding tasks, including the medial prefrontal cortex, posterior cingulate cortex, and hippocampus. Together, these results suggest that functional connectivity between the frontal lobes and basal ganglia during set shifting contributes to more efficient performance and that dopamine modulates this corticostriatal connectivity.
Asunto(s)
Atención/fisiología , Cuerpo Estriado/fisiopatología , Dopamina/deficiencia , Lóbulo Frontal/fisiopatología , Pruebas Neuropsicológicas , Adulto , Aminoácidos/sangre , Mapeo Encefálico , Cuerpo Estriado/irrigación sanguínea , Método Doble Ciego , Femenino , Alimentos Formulados/efectos adversos , Lóbulo Frontal/irrigación sanguínea , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Vías Nerviosas/irrigación sanguínea , Vías Nerviosas/fisiopatología , Oxígeno/sangre , Psicofísica , Tiempo de Reacción/fisiologíaRESUMEN
Anagram tasks are frequently used in cognitive research, and the generation of new scrambled letter combinations is a task well suited to a software solution. Most available programs, however, do not allow experimenters to generate new anagrams flexibly or to characterize existing anagrams using psycholinguistic criteria. They also do not provide detailed information on their source dictionaries. We present anagram software that interfaces with CELEX2, an internationallyrecognized psycholinguistic database. This software allows users to capitalize on lexical variables and thus enables direct control of psycholinguistic features that may influence the cognitive processes involved in anagram solution.