Regional, Layer, and Cell-Type-Specific Connectivity of the Mouse Default Mode Network

Area of Science:

• Neuroscience
• Brain Anatomy
• Systems Neuroscience

Background:

• The default mode network (DMN) is a crucial brain network active during rest.
• The DMN is implicated in various brain disorders, but its structural connectivity is poorly understood.
• Investigating the DMN's anatomy in mice can provide cell-type resolution insights.

Purpose of the Study:

• To map the structural connectivity of the mouse default mode network (DMN).
• To elucidate the projection patterns of different neuronal populations within the DMN.
• To provide a multi-scale anatomical description of the DMN.

Main Methods:

• Co-registration of functional magnetic resonance imaging (fMRI) and axonal tracing data.
• Utilizing the 3D Allen mouse brain reference atlas for spatial mapping.
• Analyzing projection patterns of DMN layer 2/3 (L2/3) and layer 5 (L5) neurons.

Main Results:

• The mouse DMN comprises preferentially interconnected cortical regions.
• DMN L2/3 neurons primarily project within the DMN.
• DMN L5 neurons exhibit both intra-DMN and extra-DMN projections, with distinct subtypes identified in the retrosplenial cortex.

Conclusions:

• This study provides a detailed, multi-scale anatomical map of the mouse DMN.
• Understanding DMN structural connectivity is crucial for deciphering its role in brain function and disease.
• Distinct projection patterns of DMN neurons offer potential targets for future research into neurological disorders.