Dissociation of Striosome and Matrix Activation in the Human Striatum During the Cue and Execution Phases of Working Memory.

The striatum comprises two neurochemically and anatomically distinct tissue compartments, the striosome and matrix, that are hypothesized to support different aspects of cognition and action. In animal studies, the striosome has been linked to reward evaluation, emotional learning, and decision-making under conflict, whereas the matrix is more closely associated with sensorimotor integration and task execution. However, evidence for compartment-specific function in humans is limited and indirect. Using probabilistic tractography, we identified voxels with striosome-like and matrix-like patterns of structural connectivity in healthy adults. We then examined how these compartment-like voxels responded to task demands during an fMRI Key Points: Striatal medium spiny neurons are organized into two interdigitated compartments, the striosome and matrix, which are embryologically, pharmacologically, and anatomically distinct. Compartment-specific functions have been demonstrated in animals, but their roles in human cognition are unexplored.We found that in humans, striosome-like voxels preferentially activated during memory cues, while matrix-like voxels preferentially activated during recall and memory maintenance. In both compartments, activation scaled with task difficulty.Activation in striosome-like voxels scaled more strongly with task accuracy and difficulty, suggesting a striosome-selective role in vigilance and/or motivation.