Myoga, M. H. | bioRxiv Science

bioRxiv2024

Nfib regulates progenitor competence in maturation of GABAergic neurons

Diverse types of GABAergic projection neurons and interneurons of the telencephalon derive from progenitors in a ventral germinal zone, called the ganglionic eminence. Using single-cell transcriptomics, chromatin accessibility profiling, lineage tracing, birthdating, heterochronic transplantation, and perturbation sequencing in mouse embryos, we investigated how progenitor competence influences the maturation and differentiation of these neurons. We found that the progression of neurogenesis over developmental time shapes maturation competence in ganglionic eminence progenitors, influencing how they progress into mature states. In contrast, differentiation competence, which defines the ability to produce diverse transcriptomic identities, remains largely unaffected by the stages of neurogenesis. Chromatin remodeling alongside a NFIB-driven regulatory gene module influences maturation competence in late-born neurons. These findings provide key insights into how transcriptional programs and chromatin accessibility govern neuronal maturation and the diversification of GABAergic neuron subtypes during neurodevelopment.

neuroscience↗

bioRxiv2023

The Dynamics of Context-Dependent Space Representations in AC

Auditory space is not mapped onto the receptor surface in the inner ear but results from complex neuronal computations by our brain. However, there is no consensus about the resulting neuronal representation of space in auditory cortex (AC) owing to contradicting reports: While many studies found a tuning preference for sound source positions in the contralateral hemisphere, others have observed an additional population of cells tuned to midline positions or even context-dependent dynamic changes in the tuning of individual cells. A fundamental difference across studies was the animals brain state, which might affect AC processing and thus the apparent nature of its spatial code. Yet no study to date investigated spatial tuning of identified AC neurons across brain states. Here, we employed longitudinal two-photon calcium imaging in the AC of mice under distinct states of wakefulness: anesthetized, idle awake, and during involvement in a go/no-go localization task. We find that previously reported differences in coding regimes are directly linked to wakefulness: A strong contralateral tuning bias is present under anesthesia, while pronounced and stable mid-line tuning appeared in awake but idle animals. Intriguingly, in localizing mice, tuning was different again with a large proportion of AC neurons responding to the position of the currently relevant sound-source. These population regimes remained stable across imaging sessions despite the spatial tuning of individual neurons being highly variable. Our findings resolve apparent contradictions in the literature and thus give a dynamical explanation for the multiple space representations in the AC.

neuroscience↗