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Cortical microcircuit

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...
August 6, 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...
April 24, 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
Shervin Safavi, Abhilash Dwarakanath, Vishal Kapoor, Joachim Werner, Nicholas G Hatsopoulos, Nikos K Logothetis, Theofanis I Panagiotaropoulos
Correlated fluctuations of single neuron discharges, on a mesoscopic scale, decrease as a function of lateral distance in early sensory cortices, reflecting a rapid spatial decay of lateral connection probability and excitation. However, spatial periodicities in horizontal connectivity and associational input as well as an enhanced probability of lateral excitatory connections in the association cortex could theoretically result in nonmonotonic correlation structures. Here, we show such a spatially nonmonotonic correlation structure, characterized by significantly positive long-range correlations, in the inferior convexity of the macaque prefrontal cortex...
April 10, 2018: Proceedings of the National Academy of Sciences of the United States of America
Taylor W Schmitz, John Duncan
Attention alters three key properties of population neural activity - firing rate, rate variability, and shared variability between neurons. All three properties are well explained by a single canonical computation - normalization - that acts across hierarchically integrated brain systems. Combining data from rodents and nonhuman primates, we argue that cortical cholinergic modulation originating from the basal forebrain closely mimics the effects of directed attention on these three properties of population neural activity...
May 2018: Trends in Cognitive Sciences
Mathieu Niquille, Greta Limoni, Foivos Markopoulos, Christelle Cadilhac, Julien Prados, Anthony Holtmaat, Alexandre Dayer
Delineating the basic cellular components of cortical inhibitory circuits remains a fundamental issue in order to understand their specific contributions to microcircuit function. It is still unclear how current classifications of cortical interneuron subtypes relate to biological processes such as their developmental specification. Here we identified the developmental trajectory of neurogliaform cells (NGCs), the main effectors of a powerful inhibitory motif recruited by long-range connections. Using in vivo genetic lineage-tracing in mice, we report that NGCs originate from a specific pool of 5-HT3A R-expressing Hmx3+ cells located in the preoptic area (POA)...
March 20, 2018: ELife
Robert Steger, Lauren Blachorsky, Qizong Yang, Joshua C Brumberg
The properties of specific cortical cell types enable greater understanding of how cortical microcircuits process and transmit sensory, motor, and cognitive information. Previous reports have characterized the intrinsic properties of the inverted pyramidal cell (IPC) where the most prominent dendrite is orientated towards the cortical white matter. Using whole cell patch clamp recordings from rat and mouse somatosensory cortex in conjunction with electric microstimulation of the white matter we characterized the synaptic inputs onto IPCs and the more common upright pyramidal cell (UPC) in the infragranular layers...
March 2018: Somatosensory & Motor Research
Samuel Harding-Forrester, Daniel E Feldman
Somatosensory areas containing topographic maps of the body surface are a major feature of parietal cortex. In primates, parietal cortex contains four somatosensory areas, each with its own map, with the primary cutaneous map in area 3b. Rodents have at least three parietal somatosensory areas. Maps are not isomorphic to the body surface, but magnify behaviorally important skin regions, which include the hands and face in primates, and the whiskers in rodents. Within each map, intracortical circuits process tactile information, mediate spatial integration, and support active sensation...
2018: Handbook of Clinical Neurology
Robert K Naumann, Patricia Preston-Ferrer, Michael Brecht, Andrea Burgalossi
Following the groundbreaking discovery of grid cells, the medial entorhinal cortex (MEC) has become the focus of intense anatomical, physiological, and computational investigations. Whether and how grid activity maps onto cell types and cortical architecture is still an open question. Fundamental similarities in microcircuits, function, and connectivity suggest a homology between rodent MEC and human posteromedial entorhinal cortex. Both are specialized for spatial processing and display similar cellular organization, consisting of layer 2 pyramidal/calbindin cell patches superimposed on scattered stellate neurons...
June 1, 2018: Journal of Neurophysiology
Dibyadeep Datta, Amy F T Arnsten
Schizophrenia is associated with core deficits in cognitive abilities and impaired functioning of the newly evolved prefrontal association cortex (PFC). In particular, neuropathological studies of schizophrenia have found selective atrophy of the pyramidal cell microcircuits in deep layer III of the dorsolateral PFC (dlPFC) and compensatory weakening of related GABAergic interneurons. Studies in monkeys have shown that recurrent excitation in these layer III microcircuits generates the precisely patterned, persistent firing needed for working memory and abstract thought...
March 1, 2018: ACS Chemical Neuroscience
Margaret I Davis, Jill R Crittenden, Austin Y Feng, David A Kupferschmidt, Alipi Naydenov, Nephi Stella, Ann M Graybiel, David M Lovinger
Presynaptic cannabinoid-1 receptors (CB1-R) bind endogenous and exogenous cannabinoids to modulate neurotransmitter release. CB1-Rs are expressed throughout the basal ganglia, including striatum and substantia nigra, where they play a role in learning and control of motivated actions. However, the pattern of CB1-R expression across different striatal compartments, microcircuits and efferent targets, and the contribution of different CB1-R-expressing neurons to this pattern, are unclear. We use a combination of conventional techniques and novel genetic models to evaluate CB1-R expression in striosome (patch) and matrix compartments of the striatum, and in nigral targets of striatal medium spiny projection neurons (MSNs)...
2018: PloS One
Gabriele Radnikow, Dirk Feldmeyer
From an anatomical point of view the neocortex is subdivided into up to six layers depending on the cortical area. This subdivision has been described already by Meynert and Brodmann in the late 19/early 20. century and is mainly based on cytoarchitectonic features such as the size and location of the pyramidal cell bodies. Hence, cortical lamination is originally an anatomical concept based on the distribution of excitatory neuron. However, it has become apparent in recent years that apart from the layer-specific differences in morphological features, many functional properties of neurons are also dependent on cortical layer or cell type...
2018: Frontiers in Neuroanatomy
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