Surface-based tractography uncovers 'what' and 'where' pathways in prefrontal cortex.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroanatomy

Background:

• The frontal eye field (FEF) and inferior frontal junction (IFJ) are prefrontal regions involved in top-down control.
• Neuroimaging suggests FEF specializes in spatial processing and IFJ in non-spatial processing.

Purpose of the Study:

• To investigate if unique structural connectivity patterns underlie the specialized roles of FEF and IFJ.
• To map the structural connections of FEF and IFJ to the dorsal and ventral visual streams.

Main Methods:

• Activation likelihood estimation meta-analysis to localize FEF and IFJ.
• Surface-based probabilistic tractography in 56 subjects to track white matter connections.
• Utilized the Glasser et al. (2016) multimodal atlas for brain parcellation.

Main Results:

• FEF showed predominant structural connectivity to the dorsal visual stream, especially in the left hemisphere.
• IFJ exhibited predominant structural connectivity to the ventral visual stream bilaterally.
• The superior longitudinal fasciculus's first and third branches were implicated as segregated pathways connecting FEF and IFJ to the posterior parietal cortex.

Conclusions:

• Structural connectivity fingerprints support the specialization of FEF for spatial control and IFJ for non-spatial control.
• These findings suggest visual stream architectures extend into the posterior lateral prefrontal cortex.
• Provides converging anatomical evidence for distinct functional roles based on connectivity.