Biology subjects

Klingler, E.

Publications and source records attributed to Klingler, E..

8 recordsLinked to original sources

bioRxiv2026

Prenatal assembly of functional cortical circuits

The extent to which early brain maturation requires interactions with the outside world is a central question in neurobiology. Because much of cortical maturation occurs after birth in Mus, it has often been viewed as dependent on postnatal experience. However, studies addressing this issue have largely relied on postnatal sensory deprivation paradigms, which perturb normal development and cannot determine to what extent postnatal experience per se drives maturation. To address this question, here we compare two related rodents with markedly different gestation lengths: the precocial Acomys dimidiatus (39-day gestation) and the altricial Mus musculus (19-day gestation). By generating a novel Acomys reference genome and using histology, cellular birth dating, electrophysiology, single-nucleus transcriptomics, and quantitative behavior, we show that Acomys preserves the canonical sequence and timing of cortical development, while shifting major milestones of neuronal, circuit and behavioral maturation into prenatal life. At birth, Acomys cortex already shows advanced cytoarchitecture, neuronal physiology, thalamocortical barrels, transcriptional states, and sensorimotor behavior, with postnatal molecular programs in Mus unfolding prenatally in Acomys. Thus, birth is not a prerequisite for early cortical maturation. Instead, evolutionarily conserved developmental programs unfold across birth, with birth occurring at different stages of these programs, reflecting a species-specific balance between neonatal competence and prolonged postnatal plasticity.

neuroscience↗

bioRxiv2025

Developmental gene expression patterns driving species-specific cortical features

The cerebral cortex shows species-specific variations in size and organization, likely accounting for distinct behavioral abilities. These structural differences may reflect evolutionary changes in the developmental expression of shared genes. To investigate this possibility, we compared cell-type-specific gene expression across species in the developing mouse and human neocortex, and human cortical organoids, by generating a shared transcriptional reference framework. This identified genes with conserved/divergent expression patterns, providing a molecular foundation to interrogate species-specific cellular properties. Using this resource, we discovered that the transcription factor JUNB is expressed in human but not mouse progenitors. Through cell-type-specific gain- and loss-of-function experiments in mice and human organoids, we demonstrate that JUNB bidirectionally controls human cortical features, including progenitor proliferation rates, neuronal production timing, and total neuronal output. This reveals how cell-type-specific regulation of shared genes during development can drive species-specific cortical features, providing a framework for understanding the molecular basis of cortical evolution.

neuroscience↗

bioRxiv2024

Cell-extrinsic controls over neocortical neuron fate and diversity

Cellular diversity in the neocortex emerges gradually during prenatal and postnatal development. While environmental interactions occur during this extended maturation period, the impact of extrinsic cues on determining the fate of distinct neuron types remains unknown. To address this question, we exposed developing neocortical cells to various environmental conditions and examined how this affects cell fate and diversity. Our developmental analyses reveal a hierarchical molecular program in which cell class-distinguishing features emerge first, followed by subclass- and type-related characteristics, with distinct developmental paces among cell populations. Environmental contribution was assessed in vivo, using genetically modified mice models in which position or innervation are altered, and in vitro using two-dimensional cultures. Acquisition of cellular identity and diversity remained stable across in vivo models. In contrast, in vitro glutamatergic neurons showed decreased expression of identity-defining genes, reduced diversity and alterations in canonical cortical connectivity. Cellular identity and diversity were restored towards in vivo values in organotypic slice cultures. These findings reveal cell population-specific responses to environmental conditions and highlight the role of extracellular context in shaping cell diversity in the maturing neocortex.

neuroscience↗

bioRxiv2024

Emergence of neocortical function in heterotopic neurons

Brains come in various sizes and shapes, yet how neuronal position constrains the type of circuits that they can form remains largely unknown. The spatial layout of anatomical structures with corresponding functions varies widely across species (J-4). Also, during evolution, anatomical structures have duplicated and then diverged to generate new circuits and functions (5, 6). Thus, it is critical to understand how the position of neurons constrains their integration into circuits and, ultimately, their function. To address this question, we studied EmlJ knockout mice in which subsets of neocortical neurons form a new structure below the neocortex termed heterotopia (Ht). We examined how this new location affects the molecular identity, topography, input-output circuit connectivity, electrophysiology, and functional properties of these neurons. Our results reveal a striking conservation of the cellular features and circuit properties of Ht neurons, despite their abnormal location and misorientation. Supporting this observation, these neurons were able to functionally substitute for overlying neocortical neurons in a behaviorally relevant task when the latter were optogenetically silenced. Hence, specific neuronal identities and associated function can be reproduced in altered anatomical settings, revealing a remarkable level of self-organization and adaptability of neocortical circuits.

neuroscience↗

bioRxiv2023

Developmental molecular controls over arealization of descending cortical motor pathways

Layer 5 extratelencephalic (ET) neurons are a main class of neocortical projection neurons that predominate in the motor cortex and send their axon to the pons and spinal cord, and collaterals to the thalamus and multiple deep subcerebral structures1-3. Precise connectivity of ET neurons is critical for fine motor control; they are central to loss of function upon spinal cord injury and specifically degenerate in select neurodegenerative disorders4, 5. ET neurons consist of several types of cells with distinct laminar and areal locations, molecular identities, connectivities, and functions6, 7. Within layer 5 of the cortex, two cardinal subtypes of ET neurons have been identified: "ETlower" neurons, which express Slco2a1 and project to distal targets including the spinal cord, "ETupper" neurons, which express Nprs1 or Hpgd and project more proximally to the pons and thalamus6. Despite their critical function, how these neuronal subtypes emerge during development and acquire their area-specific distributions remains unaddressed. Here, using combinations of anatomical labeling, MAPseq mapping8, and single-nucleus transcriptomics across developing cortical areas, we reveal that these two subtypes of ET neurons are present at birth along opposite antero-posterior cortical gradients. We first characterize area-specific developmental axonal dynamics of ETlower and ETupper neurons and find that the latter can emerge by pruning of subsets of ETlower neurons. We next identify area- and ET neuron type-specific developmental transcriptional programs to identify key target genes in vivo. Finally, we reprogram ET neuron area-specific connectivity from motor to visual by postnatal in vivo combinatorial knockout of three key type-specific transcription factors. Together, these findings delineate the functional transcriptional programs controlling ET neuron diversity across cortical areas and provide a molecular blueprint to investigate and direct the developmental emergence of corticospinal motor control.

neuroscience↗

bioRxiv2021

MiR-137 and miR-122, two outer subventricular zone-enriched non-coding RNAs, regulate basal progenitor expansion and neuronal differentiation

Cortical expansion in the primate brain relies on the presence and the spatial enlargement of multiple germinal zones during development and on a prolonged developmental period. In contrast to other mammals, which have two cortical germinal zones, the ventricular zone (VZ) and subventricular zone (SVZ), gyrencephalic species display an additional germinal zone, the outer subventricular zone (OSVZ), which role is to increase the number and types of neurons generated during corticogenesis. How the OSVZ emerged during evolution is poorly understood but recent studies suggest a role for non-coding RNAs, which allow tight regulations of transcriptional programs in time and space during development (Dehay et al. 2015; Arcila et al., 2014). Here, using in vivo functional genetics, single-cell RNA sequencing, live imaging and electrophysiology to assess progenitor and neuronal properties in mice, we identify two ferret and human OSVZ-enriched microRNAs (miR), miR-137 and miR-122, which regulate key cellular features associated with cortical expansion. MiR-137 promotes basal progenitor self-replication and superficial layer neuron fate, while miR-122 slows down neuronal differentiation pace. Together, these findings support a cell-type specific role for miR-mediated transcriptional regulation in cortical expansion.

evolutionary biology↗

bioRxiv2018

Single-cell molecular connectomics of intracortically-projecting neurons

The neocortex is organized into distinct areas, whose interconnectivity underlies sensorimotor transformations and integration1-7. These behaviorally critical functions are mediated by intracortically-projecting neurons (ICPN), which are a heterogeneous population of cells sending axonal branches to distinct cortical areas as well as to subcortical targets8-10. Although population-based11-14 and single-cell15-19 intracortical wiring diagrams are being identified, the transcriptional signatures corresponding to single-cell axonal projections of ICPN to multiple sites remain unknown. To address this question, we developed a high-throughput approach, \"ConnectID\", to link connectome and transcriptome in single neurons. ConnectID combines MAPseq projection mapping17,20 (to identify single-neuron multiplex projections) with single-cell RNA sequencing (to identify corresponding gene expression). Using primary somatosensory cortex (S1) ICPN as proof-of-principle neurons, we identify three cardinal targets: (1) the primary motor cortex (M1), (2) the secondary somatosensory cortex (S2) and (3) subcortical targets (Sub). Using ConnectID, we identify transcriptional modules whose combined activities reflect multiplex projections to these cardinal targets. Based on these findings, we propose that the combinatorial activity of connectivity-defined transcriptional modules serves as a generic molecular mechanism to create diverse axonal projection patterns within and across neuronal cell types.

neuroscience↗

bioRxiv2018

A translaminar genetic logic for the circuit identity of intracortically-projecting neurons

Distinct subtypes of intracortically-projecting neurons (ICPN) are present in all layers, allowing propagation of information within and across cortical columns. How the molecular identities of ICPN relate to their defining anatomical and functional properties is unknown. Here we show that the transcriptional identities of ICPN primarily reflect their input-output connectivities rather than their birth dates or laminar positions. Thus, conserved circuit-related transcriptional programs are at play across cortical layers, which may preserve canonical circuit features across development and evolution.

neuroscience↗