Cell type specializations of the vocal-motor cortex in songbirds

SUMMARY

Identifying molecular specializations in cortical circuitry supporting complex behaviors, like learned vocalizations, requires understanding of the neuroanatomical context from which these circuits arise. In songbirds, the robust arcopallial nucleus (RA) provides descending cortical projections for fine vocal-motor control. Using single-nuclei transcriptomics and spatial gene expression mapping in zebra finches, we have defined cell types and molecular specializations that distinguish RA from adjacent regions involved in non-vocal motor and sensory processing. We describe an RA-specific projection neuron, differential inhibitory subtypes, and glia specializations and have probed predicted GABAergic interneuron subtypes electrophysiologically within RA. Several cell-specific markers arise developmentally in a sex-dependent manner. Our interactive apps integrate cellular data with developmental and spatial distribution data from the gene expression brain atlas ZEBrA. Users can explore molecular specializations of vocal-motor neurons and support cells that likely reflect adaptations key to the physiology and evolution of vocal control circuits and refined motor skills.

Graphical abstract

In brief

Nevue et al. define cell types in the vocal robust arcopallial nucleus (RA) and adjacent areas of zebra finches based on snRNA-seq. They demonstrate neuronal and astrocyte types unique to RA and how cell-defining markers arise during vocal development. Cell type and developmental transcriptomics datasets can be easily mined with interactive applications.