Tulsi Patel (Wichterle Lab)

Transcriptional regulation of neuronal maturation

The formation of a functional nervous system requires the correct specification and maturation of nerve cells. Most neurons are generated during a brief embryonic window, but the nervous system continues to mature for weeks in mice and years in humans. To dissect the transcriptional regulation of maturation, we have mapped the gene expression and chromatin accessibility profiles of mouse spinal motor neurons throughout their lifetime. We found that motor neurons reach transcriptional maturity during the third postnatal week, when motor function also becomes adult-like, and identified unique combinations of transcription factors that regulate gene expression during early and late stages of maturation. We are now developing methods to generate mature motor neurons from stem cells in order to better model adult-specific diseases in culture.

Marie Labouesse (Kellendonk Lab)

New players in the brain circuits of movement: Striatal D1 axonal collaterals to the GPe act as a second direct pathway to support motor control

The striatum is a well-established brain region within the basal ganglia that regulates motor behavior. Its neuronal projections are divided into two routes: a direct (D1) and an indirect pathway (D2), classically depicted as having opposite effects on movement and distinct target regions. Interestingly, several anatomical studies have described the existence of axonal collaterals (“bridging collaterals”): neuronal bridges arising from D1 neurons yet contacting the target region of D2 neurons: the globus pallidus (GPe). Their relevance for behavior is, however, unknown, Here, we used a combination of genetic targeting, in vivo calcium imaging, chemogenetic/optogenetic manipulations and deep learning-based behavioral tracking (DeepLabCut) to determine the role of D1 bridging collaterals in motor function in mice.