Shared and distinct transcriptomic cell types across neocortical areas

Area of Science:

• Neuroscience
• Genomics
• Cell Biology

Background:

• The neocortex exhibits diverse cell types organized into layers and distinct functional areas.
• Understanding cell type diversity is crucial for deciphering brain function.

Purpose of the Study:

• To investigate the transcriptomic diversity of cell types across functionally distinct regions of the mouse neocortex.
• To establish a taxonomy of cortical cell types based on gene expression and long-range projections.

Main Methods:

• Deep single-cell RNA sequencing of 23,822 cells from the primary visual cortex and anterior lateral motor cortex.
• Integration of transcriptomic data with retrograde labeling to determine projection specificity of glutamatergic neurons.

Main Results:

• Identification of 133 distinct transcriptomic cell types.
• Nearly all γ-aminobutyric acid (GABA)-containing neuron types were shared between the two areas.
• Most glutamatergic neuron types were specific to either the visual or motor cortex.

Conclusions:

• Cortical cell type composition varies significantly between functionally distinct areas, particularly for glutamatergic neurons.
• A combined transcriptomic and projectional taxonomy provides a comprehensive classification of mouse cortical cell types.
• This study advances our understanding of neocortical organization and cell type heterogeneity.