Critical Regions and Connections Form Pathways and Clusters in the Mouse Brain.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Network Science

Background:

• Understanding brain function principles requires cross-species connectome network analysis.
• Mesoscale tract-tracing data provides a detailed map of neural connections.

Purpose of the Study:

• To examine fundamental network properties (global efficiency, betweenness centrality, clustering) in the mouse connectome.
• To identify critical brain regions and connections using vulnerability analysis based on network function loss.
• To assess the robustness of findings to noise and connection strength.

Main Methods:

• Analysis of mesoscale tract-tracing data from the mouse connectome.
• Application of vulnerability analysis by systematically removing 213 brain regions and 16,594 connections.
• Evaluation of network function loss, robustness to noise, and importance of connection strength.

Main Results:

• Identification of eight critical regions and 38 critical connections, with limbic regions being dominant.
• Discovery of two main functional pathways (piriform cortex to globus pallidus; entorhinal cortex to amygdala) and two clusters (caudoputamen, entorhinal cortex).
• Correlation between critical components and brain functions including olfaction, learning, memory, affect, and motor processing; the claustrum identified as critical for integration and motor translation.

Conclusions:

• Vulnerability analysis is a powerful approach for characterizing fundamental nervous system structure.
• Global network properties can sometimes deviate from local network properties, highlighting complex interactions.
• The identified critical regions and pathways are crucial for integrating diverse brain functions.