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Cortical microcircuit

Vincent Magloire, Marion S Mercier, Dimitri M Kullmann, Ivan Pavlov
Seizures are complex pathological network events characterized by excessive and hypersynchronized activity of neurons, including a highly diverse population of GABAergic interneurons. Although the primary function of inhibitory interneurons under normal conditions is to restrain excitation in the brain, this system appears to fail intermittently, allowing runaway excitation. Recent developments in optogenetics, combined with genetic tools and advanced electrophysiological and imaging techniques, allow us for the first time to assess the causal roles of identified cell-types in network dynamics...
October 15, 2018: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
Richard E Rosch, Sukhvir Wright, Gerald Cooray, Margarita Papadopoulou, Sushma Goyal, Ming Lim, Angela Vincent, A Louise Upton, Torsten Baldeweg, Karl J Friston
NMDA-receptor antibodies (NMDAR-Abs) cause an autoimmune encephalitis with a diverse range of EEG abnormalities. NMDAR-Abs are believed to disrupt receptor function, but how blocking this excitatory synaptic receptor can lead to paroxysmal EEG abnormalities-or even seizures-is poorly understood. Here we show that NMDAR-Abs change intrinsic cortical connections and neuronal population dynamics to alter the spectral composition of spontaneous EEG activity and predispose brain dynamics to paroxysmal abnormalities...
September 27, 2018: Proceedings of the National Academy of Sciences of the United States of America
Erik Ellwardt, Gautam Pramanik, Dirk Luchtman, Tanja Novkovic, Eduardo Rosales Jubal, Johannes Vogt, Isabelle Arnoux, Christina Francisca Vogelaar, Shibajee Mandal, Melanie Schmalz, Zeke Barger, Inigo Ruiz de Azua, Tanja Kuhlmann, Beat Lutz, Thomas Mittmann, Stefan Bittner, Frauke Zipp, Albrecht Stroh
Multiple sclerosis (MS) patients exhibit neuropsychological symptoms in early disease despite the immune attack occurring predominantly in white matter and spinal cord. It is unclear why neurodegeneration may start early in the disease and is prominent in later stages. We assessed cortical microcircuit activity by employing spiking-specific two-photon Ca2+ imaging in proteolipid protein-immunized relapsing-remitting SJL/J mice in vivo. We identified the emergence of hyperactive cortical neurons in remission only, independent of direct immune-mediated damage and paralleled by elevated anxiety...
October 2018: Nature Neuroscience
Stephanie C Seeman, Luke Campagnola, Pasha A Davoudian, Alex Hoggarth, Travis A Hage, Alice Bosma-Moody, Christopher A Baker, Jung Hoon Lee, Stefan Mihalas, Corinne Teeter, Andrew L Ko, Jeffrey G Ojemann, Ryder P Gwinn, Daniel L Silbergeld, Charles Cobbs, John Phillips, Ed Lein, Gabe Murphy, Christof Koch, Hongkui Zeng, Tim Jarsky
Generating a comprehensive description of cortical networks requires a large-scale, systematic approach. To that end, we have begun a pipeline project using multipatch electrophysiology, supplemented with two-photon optogenetics, to characterize connectivity and synaptic signaling between classes of neurons in adult mouse primary visual cortex (V1) and human cortex. We focus on producing results detailed enough for the generation of computational models and enabling comparison with future studies. Here, we report our examination of intralaminar connectivity within each of several classes of excitatory neurons...
September 26, 2018: ELife
Arabinda Mishra, Shantanu Majumdar, Feng Wang, George H Wilson, John C Gore, Li Min Chen
Whereas resting state blood oxygenation-level dependent (BOLD) functional MRI has been widely used to assess functional connectivity between cortical regions, the laminar specificity of such measures is poorly understood. This study aims to determine: (a) whether the resting state functional connectivity (rsFC) between two functionally related cortical regions varies with cortical depth, (b) the relationship between layer-resolved tactile stimulus-evoked activation pattern and interlayer rsFC pattern between two functionally distinct but related somatosensory areas 3b and 1, and (c) the effects of spatial resolution on rsFC measures...
September 25, 2018: Human Brain Mapping
F Ortiz, W P K Zapfe, A Draguhn, R Gutiérrez
Fast ripples (FRs; activity of >250 Hz) have been considered as a biomarker of epileptic activity in the hippocampus and entorhinal cortex; it is thought that they signal the focus of seizure generation. Similar high frequency network activity has been produced in vitro by changing extracellular medium composition, by using pro-epileptic substances, or by electrical stimulation. We here study the propagation of these events between different subregions of the male rat hippocampus in a recently introduced experimental model of FRs in entorhinal cortex-hippocampal slices in vitro By using a matrix of 4096 microelectrodes, the sites of initiation, propagation pathways, and spatiotemporal characteristics of activity patterns could be studied with unprecedented high resolution...
September 6, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Isabelle Arnoux, Michael Willam, Nadine Griesche, Jennifer Krummeich, Hirofumi Watari, Nina Offermann, Stephanie Weber, Partha Narayan Dey, Changwei Chen, Olivia Monteiro, Sven Buettner, Katharina Meyer, Daniele Bano, Konstantin Radyushkin, Rosamund Langston, Jeremy J Lambert, Erich Wanker, Axel Methner, Sybille Krauss, Susann Schweiger, Albrecht Stroh
Catching primal functional changes in early, 'very far from disease onset' (VFDO) stages of Huntington's disease is likely to be the key to a successful therapy. Focusing on VFDO stages, we assessed neuronal microcircuits in premanifest Hdh150 knock-in mice. Employing in vivo two-photon Ca2+ imaging, we revealed an early pattern of circuit dysregulation in the visual cortex - one of the first regions affected in premanifest Huntington's disease - characterized by an increase in activity, an enhanced synchronicity and hyperactive neurons...
September 4, 2018: ELife
Vafa Andalibi, Henri Hokkanen, Simo Vanni
Simulation of the cerebral cortex requires a combination of extensive domain-specific knowledge and efficient software. However, when the complexity of the biological system is combined with that of the software, the likelihood of coding errors increases, which slows model adjustments. Moreover, few life scientists are familiar with software engineering and would benefit from simplicity in form of a high-level abstraction of the biological model. Our primary aim was to build a scalable cortical simulation framework for personal computers...
August 27, 2018: Neural Computation
Richard E Rosch, Ryszard Auksztulewicz, Pui Duen Leung, Karl J Friston, Torsten Baldeweg
BACKGROUND: Disturbances in N-methyl-D-aspartate receptors (NMDARs)-as implicated in patients with schizophrenia-can cause regionally specific electrophysiological effects. Both animal models of NMDAR blockade and clinical studies in patients with schizophrenia have suggested that behavioral phenotypes are associated with reduction in inhibition within the frontal cortex. METHODS: Here we investigate event-related potentials to a roving auditory oddball paradigm under ketamine in healthy human volunteers (N= 18; double-blind, placebo-controlled, crossover design)...
August 13, 2018: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
Joshua B Burt, Murat Demirtaş, William J Eckner, Natasha M Navejar, Jie Lisa Ji, William J Martin, Alberto Bernacchia, Alan Anticevic, John D Murray
Hierarchy provides a unifying principle for the macroscale organization of anatomical and functional properties across primate cortex, yet microscale bases of specialization across human cortex are poorly understood. Anatomical hierarchy is conventionally informed by invasive tract-tracing measurements, creating a need for a principled proxy measure in humans. Moreover, cortex exhibits marked interareal variation in gene expression, yet organizing principles of cortical transcription remain unclear. We hypothesized that specialization of cortical microcircuitry involves hierarchical gradients of gene expression...
September 2018: Nature Neuroscience
Ashok S Chauhan, Joseph D Taylor, Alain Nogaret
During cognitive tasks cortical microcircuits synchronize to bind stimuli into unified perception. The emergence of coherent rhythmic activity is thought to be inhibition-driven and stimulation-dependent. However, the exact mechanisms of synchronization remain unknown. Recent optogenetic experiments have identified two neuron sub-types as the likely inhibitory vectors of synchronization. Here, we show that local networks mimicking the soma-targeting properties observed in fast-spiking interneurons and the dendrite-projecting properties observed in somatostatin interneurons synchronize through different mechanisms which may provide adaptive advantages by combining flexibility and robustness...
July 30, 2018: Scientific Reports
Gonzalo Martín-Vázquez, Toshitake Asabuki, Yoshikazu Isomura, Tomoki Fukai
Motor cortical microcircuits receive inputs from dispersed cortical and subcortical regions in behaving animals. However, how these inputs contribute to learning and execution of voluntary sequential motor behaviors remains elusive. Here, we analyzed the independent components extracted from the local field potential (LFP) activity recorded at multiple depths of rat motor cortex during reward-motivated movement to study their roles in motor learning. Because slow gamma (30-50 Hz), fast gamma (60-120 Hz), and theta (4-10 Hz) oscillations temporally coordinate task-relevant motor cortical activities, we first explored the behavioral state- and layer-dependent coordination of motor behavior in these frequency ranges...
2018: Frontiers in Neuroscience
Axel Hutt, John D Griffiths, Christoph S Herrmann, Jérémie Lefebvre
In the past decade, there has been a surge of interest in using patterned brain stimulation to manipulate cortical oscillations, in both experimental and clinical settings. But the relationship between stimulation waveform and its impact on ongoing oscillations remains poorly understood and severely restrains the development of new paradigms. To address some aspects of this intricate problem, we combine computational and mathematical approaches, providing new insights into the influence of waveform of both low and high-frequency stimuli on synchronous neural activity...
2018: Frontiers in Neuroscience
Naoki Hiratani, Tomoki Fukai
Recent experimental studies suggest that, in cortical microcircuits of the mammalian brain, the majority of neuron-to-neuron connections are realized by multiple synapses. However, it is not known whether such redundant synaptic connections provide any functional benefit. Here, we show that redundant synaptic connections enable near-optimal learning in cooperation with synaptic rewiring. By constructing a simple dendritic neuron model, we demonstrate that with multisynaptic connections synaptic plasticity approximates a sample-based Bayesian filtering algorithm known as particle filtering, and wiring plasticity implements its resampling process...
July 17, 2018: Proceedings of the National Academy of Sciences of the United States of America
Emanuele Olivetti, Danilo Benozzo, Jan Bím, Stefano Panzeri, Paolo Avesani
Effective connectivity measures the pattern of causal interactions between brain regions. Traditionally, these patterns of causality are inferred from brain recordings using either non-parametric, i.e., model-free, or parametric, i.e., model-based, approaches. The latter approaches, when based on biophysically plausible models, have the advantage that they may facilitate the interpretation of causality in terms of underlying neural mechanisms. Recent biophysically plausible neural network models of recurrent microcircuits have shown the ability to reproduce well the characteristics of real neural activity and can be applied to model interacting cortical circuits...
2018: Frontiers in Computational Neuroscience
Alberto Antonietti, Jessica Monaco, Egidio D'Angelo, Alessandra Pedrocchi, Claudia Casellato
During natural learning, synaptic plasticity is thought to evolve dynamically and redistribute within and among subcircuits. This process should emerge in plastic neural networks evolving under behavioral feedback and should involve changes distributed across multiple synaptic sites. In eyeblink classical conditioning (EBCC), the cerebellum learns to predict the precise timing between two stimuli, hence EBCC represents an elementary yet meaningful paradigm to investigate the cerebellar network functioning. We have simulated EBCC mechanisms by reconstructing a realistic cerebellar microcircuit model and embedding multiple plasticity rules imitating those revealed experimentally...
November 2018: International Journal of Neural Systems
Sacha J van Albada, Andrew G Rowley, Johanna Senk, Michael Hopkins, Maximilian Schmidt, Alan B Stokes, David R Lester, Markus Diesmann, Steve B Furber
The digital neuromorphic hardware SpiNNaker has been developed with the aim of enabling large-scale neural network simulations in real time and with low power consumption. Real-time performance is achieved with 1 ms integration time steps, and thus applies to neural networks for which faster time scales of the dynamics can be neglected. By slowing down the simulation, shorter integration time steps and hence faster time scales, which are often biologically relevant, can be incorporated. We here describe the first full-scale simulations of a cortical microcircuit with biological time scales on SpiNNaker...
2018: Frontiers in Neuroscience
Brielle R Ferguson, Wen-Jun Gao
Elucidating the prefrontal cortical microcircuit has been challenging, given its role in multiple complex behaviors, including working memory, cognitive flexibility, attention, social interaction and emotional regulation. Additionally, previous methodological limitations made it difficult to parse out the contribution of certain neuronal subpopulations in refining cortical representations. However, growing evidence supports a fundamental role of fast-spiking parvalbumin (PV) GABAergic interneurons in regulating pyramidal neuron activity to drive appropriate behavioral responses...
2018: Frontiers in Neural Circuits
Jochen F Meyer, Peyman Golshani, Stelios M Smirnakis
The influence of cortical cell spiking activity on nearby cells has been studied extensively in vitro . Less is known, however, about the impact of single cell firing on local cortical networks in vivo . In a pioneering study, Kwan and Dan (Kwan and Dan, 2012) reported that in mouse layer 2/3 (L2/3), under anesthesia , stimulating a single pyramidal cell recruits ~2.1% of neighboring units. Here we employ two-photon calcium imaging in layer 2/3 of mouse V1, in conjunction with single-cell patch clamp stimulation in layer 2/3 or layer 4, to probe, in both the awake and lightly anesthetized states , how (i) activating single L2/3 pyramidal neurons recruits neighboring units within L2/3 and from layer 4 (L4) to L2/3, and whether (ii) activating single pyramidal neurons changes population activity in local circuit...
2018: Frontiers in Neural Circuits
María Sáez, Maya Ketzef, Javier Alegre-Cortés, Ramón Reig, Gilad Silberberg
Focal administration of pharmacological agents during in vivo recordings is a useful technique to study the functional properties of neural microcircuits. However, the lack of visual control makes this task difficult and inaccurate, especially when targeting small and deep regions where spillover to neighboring regions is likely to occur. An additional problem with recording stability arises when combining focal drug administration with in vivo intracellular recordings, which are highly sensitive to mechanical vibrations...
June 15, 2018: Neuroscience
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