Organization of retrosplenial cortex projections at the single-neuron level.

Single-neuron analysis reveals three major projection routes and ten projection subtypes in the retrosplenial cortex, with distinct target-specific profiles.

• Why it matters: Understanding the detailed output architecture of the retrosplenial cortex is crucial for insights into its role in spatial cognition, memory, and brain-wide information integration, yet this architecture remains poorly characterized at the single-neuron level.
• What they did: Using fluorescence micro-optical sectioning tomography (fMOST), researchers reconstructed sparsely labeled neurons from the anterior RSP across the whole brain, classifying them into ten subtypes based on projection patterns and target selectivity.
• The result: Findings show that projection patterns are associated with somatic location and features, with TBC-pattern neurons displaying complex collateralization and cross-network projection modes, providing a detailed anatomical map for understanding distributed brain processing.