Diffusion tensor fiber tracking shows distinct corticostriatal circuits in humans

Area of Science:

• Neuroscience
• Human Brain Imaging
• Corticostriatal Connectivity

Background:

• Corticostriatal connections in primates are organized into discrete circuits, each with distinct behavioral functions.
• Invasive tracing methods used in animals are not applicable for studying human brain connectivity.
• The organization of corticostriatal connections as multiple circuits in humans remains to be demonstrated.

Purpose of the Study:

• To test the hypothesis that corticostriatal connections are organized as multiple distinct circuits in the human brain.
• To noninvasively demonstrate specific patterns of connectivity between the human striatum and cortex.

Main Methods:

• Utilized diffusion tensor imaging (DTI) axonal tracking, a noninvasive magnetic resonance technique.
• Applied DTI to demonstrate fiber tracts and map connectivity in the human brain.
• Investigated connections between specific compartments of the striatum (posterior, anterior, ventral) and cortical regions.

Main Results:

• Diffusion tensor imaging-based fiber tracking successfully demonstrated distinct corticostriatal connections in humans.
• The posterior (sensorimotor), anterior (associative), and ventral (limbic) striatal compartments showed specific connections with the cortex.
• These connections were particularly prominent with the frontal lobes, indicating segregated pathways.

Conclusions:

• Provides the first direct, noninvasive demonstration of distinct corticostriatal connections in humans.
• Supports the model of multiple, functionally specialized corticostriatal circuits in the human brain.
• Highlights the utility of diffusion tensor imaging for studying human brain connectivity noninvasively.