Diffusion tensor fiber tracking shows distinct corticostriatal circuits in humans

TLDR

Cortical connections in primates are organized into discrete circuits that perform distinct behavioral functions, but invasive tracing methods used in animals are not applicable to humans. The study aims to test whether corticostriatal connections in humans are organized into multiple distinct circuits. The authors employed diffusion tensor imaging axonal tracking, a noninvasive MRI technique, to map fiber tracts. Fiber tracking revealed that posterior, anterior, and ventral striatal compartments connect specifically to cortical regions, particularly the frontal lobes, providing the first direct evidence of distinct corticostriatal circuits in humans.

Abstract

Abstract A landmark of corticostriatal connectivity in nonhuman primates is that cortical connections are organized into a set of discrete circuits. Each circuit is assumed to perform distinct behavioral functions. In animals, most connectivity studies are performed using invasive tracing methods, which are nonapplicable in humans. To test the proposal that corticostriatal connections are organized as multiple circuits in humans, we used diffusion tensor imaging axonal tracking, a new magnetic resonance technique that allows demonstration of fiber tracts in a noninvasive manner. Diffusion tensor imaging–based fiber tracking showed that the posterior (sensorimotor), anterior (associative), and ventral (limbic) compartments of the human striatum have specific connections with the cortex, and particularly the frontal lobes. These results provide the first direct demonstration of distinct corticostriatal connections in humans.