Cortical neurons

An animal’s ability to respond to its environment relies on effectively decoding neural representations of sensory stimuli. While it is known that primary sensory cortices represent sensory stimuli through specific patterns of activity, it is unknown how these representations are preserved over time. Many primary and higher order cortices have been shown to exhibit changes in neural activity representing the same sensory stimuli even when behavior is stable, a process dubbed ‘representational drift’. This poses a critical challenge for the brain – how can animals maintain stable perception and

Cortical neurons exhibit a high degree of trial-to-trial variability in response to repeated presentations of the same stimulus. We propose that this variability serves a useful computational purpose: allowing the brain to generalize from a small number of examples. To formalize this theory, we consider a Gaussian model of few-shot classification, wherein we observe a few samples of each class, and each observation has trial-to-trial variability. Our model leads to three predictions about the optimal neural response variability that minimizes generalization error: (i) the optimal variability m

…understanding of how populations of cortical neurons adapt to varying sensory environments. Recent experiments in the mouse primary visual cortex (V1) have shown a remarkable finding: the magnitude of population responses follows a power law with respect to stimulus frequency. This power law is universal, with the same exponent observed across different statistical environments, enabling predictions of population responses to new environments and allowing the brai

Cortical neurons in vivo exhibit significant temporal variability, the source of which is crucial for understanding its computational and behavioural implications [1,2]. However, to match experimental observations, single-cell activity must fluctuate over much longer time scales than typical neural and synaptic time scales [3,4]. Balanced networks generally do not produce such slow fluctuations in firing rates, raising questions about their origin. Some theories attribute them to precise synaptic connectivity [5] according to an alternative scenario slow fluctuations in the rates result from n

Cortical neurons exhibit rich, time-dependent patterns of activity that are often selective to specific stimuli. From a dynamical systems perspective, such complex activity can be conceptualized as ON/OFF responses, or also as transient amplification. It is still unclear if transient amplification is an artifact of a carefully tuned model, or an intrinsically occurring phenomenon. Moreover, minute changes in the connectivity of amplifying networks can cause catastrophic dynamic instabilities. How biological circuits could settle into stable, yet amplifying connectivity regimes in an ever-chang

Cortical neurons exhibit rich, time-dependent patterns of activity that are often selective to specific stimuli. From a dynamical systems perspective, such complex activity can be conceptualized as transient amplification. It is still unclear if transient amplification is an artifact of a carefully tuned model, or a naturally occurring phenomenon. Moreover, minute changes in the connectivity of amplifying networks can cause catastrophic dynamic instabilities. How biological circuits could settle into stable, yet amplifying connectivity regimes in an ever-changing brain is unknown. Here, we sho

Populations of cortical neurons can respond to changes in their common input within about a millisecond. However, that response speed has a pronounced dependence on the temporal statistics of the neuron's input (Tchumatchenko etal.2011, Merino etal. 2021, Revah etal. 2024). Slowly fluctuating inputs allow for much more rapid responses. In the dynamic gain function of the individual neuron, this corresponds to a wider bandwidth under slower input correlations. Fourcaud etal. (2003) demonstrated that a wide bandwidth requires a strong voltage dependence of the action potential initiating current

Neuronal networks are at the core of the brain's vast computational capacities. Different strategies have each brought deep insights into their architecture. Yet, each method is limited in its capacity to resolve even simple subnetworks of single cells, due to the current compromise between throughput, resolution, and coverage. Viral projection tracing helps establish regional connectomes of mammalian brains. In combination with additional modification, the method can reveal cell-type-specific projection patterns. However, these maps lack single-neuron resolution. Monosynaptic connectivity tra

…the effects of IR neuromodulation on cortical neurons in vivo were investigated using high-density laminar recordings. The neocortex of anesthetized rats was exposed

Electrical activity plays a crucial role in the development of neurons and the formation of neuronal networks. Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools that can control the activity of neurons at the single-cell level by activating specific G protein signaling. In this study, we aimed to investigate whether the excitatory hM3Dq receptor is sufficient to influence the growth of dendrites and axons in cortical neurons. When activated, Gq-coupled hM3Dq leads to depolarization by increasing intracellular calcium levels. We biolistically transfecte

Epilepsy and autism spectrum disorder have a high degree of comorbidity, likely due to shared underlying predisposing factors. Loss of αV and β3 integrin subunits have been implicated in the onset of epilepsy and autism, respectively. However, the role of the αVβ3 integrin receptor in these disorders remains unclear. Integrins are heterodimeric receptors involved in mechanotransduction between the extracellular matrix and the intracellular cytoskeleton. In the brain, β3 integrin forms heterodimers with αV integrin, regulating the synaptic localization of GluA2-containig AMPA receptors (AMPARs)

…leveraged breakthroughs in culturing cortical neurons from human induce

…In this study, we measured cortical neurons derived from induced pluripotent stem cells (iPSCs) of patients with four mutations in the genes GRIN2B, SHANK3, UBTF, as well as chromosomal duplication in the 7q11.23 region and compared them to neurons derived from

Plant homeodomain finger gene 6 (PHF6) is a highly conserved chromatin associated protein that is important for neurodevelopment and hematopoiesis. Inherited or de novo mutations in the PHF6 gene cause Börjeson–Forssman–Lehmann syndrome (BFLS), a rare X-linked neurodevelopmental and endocrine disorder. Patients with BFLS present with intellectual disability (ID), which affects cognitive functioning and adaptive behaviour. To progress our understanding of how PHF6 mutations affect the nervous system in BFLS, we studied the impact of deletion of the Phf6 gene on brain development in conditional

…wake cycles can be mimicked in vitro: cortical neurons plated on Micro-Electrode Arrays (MEAs) show spontaneously synchronized, low-frequency firing patterns resembling the slow wave oscillations typical of NREM sleep. With specific compounds (e.g., Carbachol, orexin), network activity can be manipulated to switch to a wake state. To reduce the costs and ethical issues related to in vitro studies and to be more sustainable in research, i

…central nervous system (CNS) type of neurons, an equivalent understanding of the functional properties of human PNS neurons is lacking in vitro while there is a need for better characterization of electrophysiologically mature human PNS neurons. Generating subtypes of human PNS neurons opens possibilities for physiologically more relevant innervation and OoC models both in health and disease.Here, we modified existing differentiation pr

…an epileptogenic cascade in penumbra neurons.We used NS20Y cells and prima

…brain regions, including brainstem and cortical regions. Mutations and/or deletions in specific genes result in a high probability of developing PD characterised by distinct presentation. For example, complete loss of parkin function (PRKN KO) causes early onset PD and motor deficits due to the ventral midbrain dopaminergic neurons (VmDA) degeneration. Patients with disease-causing mutations in SCNA and LRRK2 genes show a widespread pathology with high aggregate burden

KCNQ1 is the pore-forming alpha subunit of a voltage-dependent potassium channel complex. It is predominantly expressed in the heart and in the inner ear, however, it is also present in the brain. Genetic variants in KCNQ1 have been linked to several disorders, like Romano-Ward syndrome, Jervell and Lange Nielson syndrome and diabetes mellitus type 2. Moreover, KCNQ1 is also discussed to contribute to the pathogenesis of Alzheimer´s disease and neurodevelopmental disorders, even though it´s function in the human brain remains unknown. In this study we aim to elucidate the function of KCNQ1 in

…is transferred from astrocytes to neurons to fulfill energetic needs and act as a signal that regulates gene expression related to neuroprotection, neuronal excitability, synaptic plasticity, and memory. N6-methyladenosine (m6A), the most abundant internal modification of RNA, influences mRNA stability, translation, transport, localization, and alternative splicing. This dynamic epitranscriptomic mark is prevalent in the nervous system, impacting various processes, including those affected by lactate, such as neurogenesis, synaptic

…glial (RG) cells, which generate cortical neurons, and function as a scaffold along which new-born neurons migrate. Therefore we aimed to study the effect of maternal gut microbiota depletion during pregnancy on RG-led neurodevelopment. Female mice were treated with an antibiotic cocktail prior to and throughout pregnancy to deplete their gut microbiota. Embryonic b

In the adult mammalian brain, there are dormant neuronal precursors located in various cortical and subcortical areas. Unlike progenitors of the canonical neurogenic niches, dormant precursors emerge prenatally and maintain a state of post-mitotic quiescence until they mature in response to yet unknown stimuli. Several reports indicated that the maturation of dormant precursors is rather slow and staggered across adulthood. Here, we directly compared the maturation rate of cortical dormant precursors to that of age-matched adult-born hippocampal neurons, derived from adult neurogenesis. To thi

…aging on the chromatin 3D structure of neurons remain largely unknown. By combining chromosome conformation capture (Hi-C) and microscopy techniq

Aims: Plastic changes of neurons in spinal cord after peripheral nerve injury remain to be elucidated. The aim of this research is to clarify plastic changes of neurons and pericellular synapses in lumbar spinal cord after sciatic nerve transection.Methods: Neurons and pericellular synapses in lumbar spinal cord of rats were analyzed 6 weeks after sciatic nerve transection. The axonal volume of cortical neurons was labeled with biotinylated dextran amine, the volume of motoneuron soma with Fluoro-Gold, cholinergic interneurons with vAchT, and pericellular synapses with vGlut1 and vAchT. They w