Dopamine depletion impairs frontostriatal functional connectivity during a set-shifting task.

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.

Anagram software for cognitive research that enables specification of psycholinguistic variables.

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.