Cerebral cortex

Healthy cerebral cortex function requires complex neuronal population activity with a diverse repertoire of timescales, from fleeting response to sensory input ($\sim$10-100 ms), to execution of complex body movements ($\sim 100-1000 ms$), to even longer timescales of working memory ($\sim 1-10 s$). How does cortex generate such a broad range of timescales? How is the timescale repertoire tuned in response to shifting behavioral demands? One potential explanation is that cortex operates close to criticality, i.e., close to a boundary between two different dynamical regimes. At criticality, flu

Recurrent dynamics are thought to be central to computation in the cerebral cortex. Yet, how these dynamics differ across areas remains unknown. Here, we used two-photon microscopy to image Ca2+ activity from hundreds of neurons and while delivering brief, focal excitatory input with near-cellular- resolution optogenetics. Specifically, we compared how the primary visual (V1) and the secondary motor (M2) cortices distinctly sustain this input while mice ran spontaneously. Single-neuron responses to focal stimulation were much more prevalent in M2 than V1. Moreover, evoked network-level dynamic

In order to analyse complex networks in the cerebral cortex, different approaches are used in computational neuroscience: microscopic network models that consider every single neuron in simulations aiming for a realistic biological description as well as heuristic firing rate or neural-mass models which deliver a simple macroscopic description. Recently, a stochastic mean-field model that describes the coarse-grained dynamics of generalized integrate-and-fire networks at the intermediate mesoscopic scale has been proposed [1,2]. The mesoscopic model accurately accounts for both single neuron d

…on the somatosensory and motor cerebral cortex of a mouse model for Glut1DS.Our analysis revealed 195 up-regulated and 71 down-regulated genes in Glut1-deficient mice compared to wild type controls. Gene set a

…connections in the mouse cerebral cortex. To sparsely and specifically transduce astrocytes with RV, a transposon vector expressing TVA, RV glycoprotein, and tdTomato under an astrocyte-specific promoter Gf

…the main postsynaptic sites in the cerebral cortex. Spines can have different morphologies: investigating their shape gives indications about the functional state of synapses during brain development. Quantifying dendritic spine shape changes will boost the comprehension of several neuropathies, such as Alzheimer and autism spectrum. Detection of dendritic spines is challenged by optical limitations. We propose a fully automated pipeline to segment and cluster spines to classify them according to th

Understanding the intricate functionality of the cerebral cortex requires integrating local circuit properties with global brain dynamics. Our study draws insights from biophysically detailed models of spiking neurons containing specific neural mechanisms, such as M-current and adaptation currents (Dalla Porta et al. Plos Comp. Bio., 2023). We incorporated these features in a mean-field model and, using human tractography data, we constructed a virtual whole-brain model consisting of 68 cortical nodes (Goldman et al. Front. Comput. Neurosci., 2023). To enhance realism, we introduced heterogene

The cerebral cortex is structured into functional areas and six horizontal layers. Within the cortex, different subtypes of neurons have distinct projections patterns and functions. To better understand how information is processed, and how the pyramidal cell output signal is formed, we need specific markers to investigate the function of more homogenous subpopulations of interneurons. In this study we used Chrna2 to specifically label a subset of Martinotti cells. With rabies viral tracers, combined with immunohistochemistry, we investigated the presynaptic connectivity of these cells, in dif

In primates, the amygdala forms projections that target large expanses of the ipsilateral cerebral cortex, from the frontal to the occipital lobe. However, it has remained unknown to what extent the amygdala complex also forms monosynaptic connections with the contralateral visual cortex, other than inferior temporal areas. Here we report on the results of 8 retrograde tracer injections (Fast Blue, and CTB conjugated with Alexa fluorophores) placed in the caudal extrastriate visual cortex of 6 marmoset monkeys (Callithrix jacchus), under Alfaxan anaesthesia, followed by 2 weeks transport time.

Understanding the principles behind how the cerebral cortex processes information requires identifying and characterizing its areal and laminar cytoarchitecture. In this context, deep learning offers a promising avenue to address these challenges by streamlining manual segmentation and offering observer-independent insights into cortical structure.We propose a deep-learning model for segmenting the cerebral cortex into areas and layers. We tested this solution on a dataset of one-dimensional cortical profiles derived from a non-human primate - common marmoset monkey (Callithrix jacchus) brain.

The cerebral cortex is known to follow a hierarchical organization, which supports information processing and ultimately determines behavior. The hierarchy has been observed in brain connectivity and cytoarchitecture, as well as the timescale of spiking activity. However, whether further dynamical features of cortical activity follow a hierarchical organization remains an open question.To address this question, we measured single-neuron statistics from the resting-state activity of macaque neocortex (N=6) from several cortical areas (V1, V4, DP, 7A, M1, PMd, vlPFC). We found some non-systemati

…the most superficial layer of the cerebral cortex, providing a transient source of excitatory inputs to immature pyramidal neurons. In the murine brain, CR cells are greatly reduced in the neocortex after postnatal week two, whereas in hippocampus, they persist throughout postnatal development and even into adulthood. During this time, they are integrated in the CA1 network, and recent work (Glærum et al. 2024) has showed that their persiste

…primates) with the larger neocortex, an evolutionary newer region of the cerebral cortex, than in species with smaller neocortex (e.g. mice). Therefore, it can be hypothesized that morphotype diversification of bRG is a feature gained in species with expanded neocortex during evolution. To examine this hypothesis, the present study analyzed the morphotypes of bRG in the evolutionary older regi

Systemic inflammation, often triggered by structural components of gut bacteria such as lipopolysaccharide (LPS), triggers inflammatory processes involving cytokines and other pro-inflammatory molecules. These signaling pathways can be modulated by dietary measures, with fermented foods having anti-inflammatory and immunomodulatory functions. In this study, the effect of sauerkraut brine on lipopolysaccharide (LPS)-induced inflammation in C57BL/6 mice was investigated. Two experiments were performed when the animals were 91 days old. In the first experiment, the animals were divided into three

…on neuronal maturation in the cerebral cortex, using a mouse model. We performed single-cell transcriptomics to analyse the transcriptomic changes in neuronal subtypes at different maturational stages. Compositional changes were validated with immunohistochemistry, while functional validation was conducted through calcium imaging and Patch-s

Development of the cerebral cortex involves many phases, including neural stem cell proliferation, neuronal migration, and differentiation. Defects in these phases lead to malformations in cortical development (MCDs). For example, disruption in neuronal migration causes lissencephaly, a form of MCD characterized by a smooth brain surface. Mutations in a number of genes, such as PAFAH1B1 (aka LIS1), DCX, TUBA1A, ARX, and DYNC1H1, are common causes behind lissencephaly. Many of those genes are involved in microtubule assembly and stabilization during neuronal migration. Recently, mutations in MA

…RNA expression profiles in the cerebral cortex of mice (6 weeks old) with

Autism spectrum disorders (ASD) are associated with a high genetic heterogeneity, yet for many of the cases, the underlying molecular causes remain elusive. While several studies have elucidated some distinct patterns, fundamental questions persist: How do mutations dispersed across numerous genes lead to the development of a phenotypically similar disorder? Essentially, it remains largely unclear whether mutations in distinct genes lead to similar molecular and cellular states within the brain. Thus, it is important to identify molecular mechanisms responsible aiming to decipher points of con

…dynamics of neural activity of the cerebral cortex supports the processing of information about external stimuli and its use in forming accurate perceptual decisions. In particular, it is unclear how activity distributed across cortical areas and frequency bands encodes information synergistically or redundantly, and how these emergent properties of interactions across areas relate to perception. Here, we aim to measure synergy and redundancy during an audiovisual task at the mesoscale level in auditory, visual

…in the electrical activity of the cerebral cortex. Slow-wave sleep (SWS) and deep anesthesia are dominated by high amplitude slow-wave oscillations (SWO, < 1 Hz). With the increase in arousal, desynchronization and low-amplitude fast rhythms arise. While SWS and wakefulness dynamics have been comprehensively described, their transition remains relatively unexplored. Tort-Colet et al (2021) previously reported the emergence of an intermediate brain state, the microarousal brain state, characterized by the rhythmic

Sepsis is a life-threatening organ dysfunction caused by an exacerbated inflammatory response to an infection. This multifactorial syndrome includes loss of hemodynamic coherence, increasing permeability and blood-brain-barrier breakdown, neuronal death, etc. The presence of cognitive deficits increases mortality. It is defined as sepsis-associated encephalopathy (SAE). Glial cells, such as astrocytes, and mostly the microglia, coordinate the immune response in the brain and are indispensable to SAE pathophysiology. This response occurs through cell signaling via cytokines, such as chemokine C

…to produce all cell lineages of the cerebral cortex, even when using pluripotent stem cell lines with notable growth biases. We leveraged Chimeroids to investigate inter-indiv

The function of the cerebral cortex relies on the cellular balance between excitatory (pyramidal cells) and inhibitory neurons (interneurons), which is disrupted in disorders such as autism or schizophrenia. The emergence of cortical function during postnatal development relies on spontaneous synchronous activity among large groups of pyramidal cells and interneurons, which later desynchronise for efficient information processing. Before this network activity shift, interneuron numbers are adjusted through activity-dependent programmed cell death mechanisms. However, the extent to which the ad

The development of the cerebral cortex involves a series of dynamic events, including cell proliferation and migration, which rely on the motor protein dynein and its regulators NDE1 and NDEL1. While the loss of function in NDE1 leads to microcephaly-related malformations of cortical development (MCDs), NDEL1 variants have not been detected in MCD patients. Here, we identified two patients with pachygyria, with or without subcortical band heterotopia (SBH), carrying the same de novo somatic mosaic NDEL1 variant, p.Arg105Pro (p.R105P). Through single-cell RNA sequencing and spatial transcriptom