Bridging Histology and Tractography: First In Vivo Visualization of Short-Range Prefrontal Connections Informed by...

Area of Science:

• Neuroscience
• Human Connectomics
• Neuroanatomy

Background:

• Histological studies in primates reveal dense short-range connections in the prefrontal cortex (PFC).
• Translating these findings to the living human brain is challenging due to limitations of non-invasive imaging methods like diffusion tractography.
• Understanding the PFC's intrinsic wiring is crucial for comprehending cognitive functions and neurological diseases.

Purpose of the Study:

• To systematically visualize histologically-defined short-range connections within and between human PFC subdivisions in vivo.
• To validate an anatomically-informed tractography approach against established histological data.
• To characterize the reliability and inter-individual variability of these PFC connections.

Main Methods:

• High-resolution probabilistic tractography informed by primate tract-tracing findings.
• Mapping of 91 histologically-defined short-range connections across five major PFC subdivisions.
• Analysis of data from 1003 individuals (547 female, 456 male).

Main Results:

• Successful reconstruction of intricate PFC connections with high precision (>80%) and accuracy (>70%) compared to histology.
• Replication of fine-grained connection patterns previously observed only in invasive studies.
• Demonstration of high test-retest reliability and significant inter-individual variability in PFC connectivity.

Conclusions:

• Linking histological data with in vivo tractography provides a powerful framework for studying the human connectome.
• This method enables precise visualization of local PFC circuitry in living humans.
• The findings open new avenues for investigating the neural basis of cognition and disease.