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Frontiers in Neural Circuits

Constance L Smith-Hicks, Peiling Cai, Alena V Savonenko, Roger H Reeves, Paul F Worley
Down syndrome (DS) is the leading chromosomal cause of intellectual disability, yet the neural substrates of learning and memory deficits remain poorly understood. Here, we interrogate neural networks linked to learning and memory in a well-characterized model of DS, the Ts65Dn mouse. We report that Ts65Dn mice exhibit exploratory behavior that is not different from littermate wild-type (WT) controls yet behavioral activation of Arc mRNA transcription in pyramidal neurons of the CA1 region of the hippocampus is altered in Ts65Dn mice...
2017: Frontiers in Neural Circuits
Qasim Bukhari, Aileen Schroeter, David M Cole, Markus Rudin
fMRI studies in mice typically require the use of anesthetics. Yet, it is known that anesthesia alters responses to stimuli or functional networks at rest. In this work, we have used Dual Regression analysis Network Modeling to investigate the effects of two commonly used anesthetics, isoflurane and medetomidine, on rs-fMRI derived functional networks, and in particular to what extent anesthesia affected the interaction within and between these networks. Experimental data have been used from a previous study (Grandjean et al...
2017: Frontiers in Neural Circuits
Satoshi Fujita, Mari Kaneko, Hiroko Nakamura, Masayuki Kobayashi
Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia...
2017: Frontiers in Neural Circuits
Takahiro Noda, Tomoki Amemiya, Tomoyo I Shiramatsu, Hirokazu Takahashi
Humans can rapidly detect regular patterns (i.e., within few cycles) without any special attention to the acoustic environment. This suggests that human sensory systems are equipped with a powerful mechanism for automatically predicting forthcoming stimuli to detect regularity. It has recently been hypothesized that the neural basis of sensory predictions exists for not only what happens (predictive coding) but also when a particular stimulus occurs (predictive timing). Here, we hypothesize that the phases of neural oscillations are critical in predictive timing, and these oscillations are modulated in a band-specific manner when acoustic patterns become predictable, i...
2017: Frontiers in Neural Circuits
David Eriksson
Not even the most informed scientist can setup a theory that takes all brain signals into account. A neuron not only receives neuronal short range and long range input from all over the brain but a neuron also receives input from the extracellular space, astrocytes and vasculature. Given this complexity, how does one describe and verify a typical brain mechanism in vivo? Common to most described mechanisms is that one focuses on how one specific input signal gives rise to the activity in a population of neurons...
2017: Frontiers in Neural Circuits
Jeannine Foley, Tamara Blutstein, SoYoung Lee, Christophe Erneux, Michael M Halassa, Philip Haydon
Rapid eye movement (REM) sleep onset is triggered by disinhibition of cholinergic neurons in the pons. During REM sleep, the brain exhibits prominent activity in the 5-8 Hz (theta) frequency range. How REM sleep onset and theta waves are regulated is poorly understood. Astrocytes, a non-neuronal cell type in the brain, respond to cholinergic signals by elevating their intracellular Ca(2+) concentration. The goal of this study was to assess the sleep architecture of mice with attenuated IP3 mediated Ca(2+) signaling in astrocytes...
2017: Frontiers in Neural Circuits
Detlef H Heck, Samuel S McAfee, Yu Liu, Abbas Babajani-Feremi, Roozbeh Rezaie, Walter J Freeman, James W Wheless, Andrew C Papanicolaou, Miklós Ruszinkó, Yury Sokolov, Robert Kozma
Ongoing fluctuations of neuronal activity have long been considered intrinsic noise that introduces unavoidable and unwanted variability into neuronal processing, which the brain eliminates by averaging across population activity (Georgopoulos et al., 1986; Lee et al., 1988; Shadlen and Newsome, 1994; Maynard et al., 1999). It is now understood, that the seemingly random fluctuations of cortical activity form highly structured patterns, including oscillations at various frequencies, that modulate evoked neuronal responses (Arieli et al...
2016: Frontiers in Neural Circuits
Daniel Knebel, Amir Ayali, Hans-Joachim Pflüger, Jan Rillich
Many motor behaviors, and specifically locomotion, are the product of an intricate interplay between neuronal oscillators known as central pattern generators (CPGs), descending central commands, and sensory feedback loops. The relative contribution of each of these components to the final behavior determines the trade-off between fixed movements and those that are carefully adapted to the environment. Here we sought to decipher the endogenous, default, motor output of the CPG network controlling the locust legs, in the absence of any sensory or descending influences...
2016: Frontiers in Neural Circuits
Antoine-Scott Badin, Francesco Fermani, Susan A Greenfield
"Neuronal assemblies" are defined here as coalitions within the brain of millions of neurons extending in space up to 1-2 mm, and lasting for hundreds of milliseconds: as such they could potentially link bottom-up, micro-scale with top-down, macro-scale events. The perspective first compares the features in vitro versus in vivo of this underappreciated "meso-scale" level of brain processing, secondly considers the various diverse functions in which assemblies may play a pivotal part, and thirdly analyses whether the surprisingly spatially extensive and prolonged temporal properties of assemblies can be described exclusively in terms of classic synaptic transmission or whether additional, different types of signaling systems are likely to operate...
2016: Frontiers in Neural Circuits
Woo H Shim, Ji-Yeon Suh, Jeong K Kim, Jaeseung Jeong, Young R Kim
Neurological recovery after stroke has been extensively investigated to provide better understanding of neurobiological mechanism, therapy, and patient management. Recent advances in neuroimaging techniques, particularly functional MRI (fMRI), have widely contributed to unravel the relationship between the altered neural function and stroke-affected brain areas. As results of previous investigations, the plastic reorganization and/or gradual restoration of the hemodynamic fMRI responses to neural stimuli have been suggested as relevant mechanisms underlying the stroke recovery process...
2016: Frontiers in Neural Circuits
Elena Kutsarova, Martin Munz, Edward S Ruthazer
It is well established that spontaneous activity in the developing mammalian brain plays a fundamental role in setting up the precise connectivity found in mature sensory circuits. Experiments that produce abnormal activity or that systematically alter neural firing patterns during periods of circuit development strongly suggest that the specific patterns and the degree of correlation in firing may contribute in an instructive manner to circuit refinement. In fish and amphibians, unlike amniotic vertebrates, sensory input directly drives patterned activity during the period of initial projection outgrowth and innervation...
2016: Frontiers in Neural Circuits
Ryan T Philips, V Srinivasa Chakravarthy
A remarkable accomplishment of self organizing models is their ability to simulate the development of feature maps in the cortex. Additionally, these models have been trained to tease out the differential causes of multiple feature maps, mapped on to the same output space. Recently, a Laterally Interconnected Synergetically Self Organizing Map (LISSOM) model has been used to simulate the mapping of eccentricity and meridional angle onto orthogonal axes in the primary visual cortex (V1). This model is further probed to simulate the development of the radial bias in V1, using a training set that consists of both radial (rectangular bars of random size and orientation) as well as non-radial stimuli...
2016: Frontiers in Neural Circuits
Martha M Bosma
Spontaneous activity (SA) modulates many aspects of neural development, including neuronal phenotype, axon path-finding and synaptic connectivity. In the embryonic mouse brainstem, SA initially is recorded in isolated cells at embryonic day (E) 9.5, and 48 h later takes the form of propagating waves. The majority of these waves originate from one midline initiation zone (InZ), which is situated within the developing serotonergic raphe. InZ cells express a t-type calcium channel, are depolarized, and have high membrane resistance, the combination of which allows spontaneous depolarization...
2016: Frontiers in Neural Circuits
Catherine Pérez-Valenzuela, Macarena F Gárate-Pérez, Ramón Sotomayor-Zárate, Paul H Delano, Alexies Dagnino-Subiabre
Chronic stress impairs auditory attention in rats and monoamines regulate neurotransmission in the primary auditory cortex (A1), a brain area that modulates auditory attention. In this context, we hypothesized that norepinephrine (NE) levels in A1 correlate with the auditory attention performance of chronically stressed rats. The first objective of this research was to evaluate whether chronic stress affects monoamines levels in A1. Male Sprague-Dawley rats were subjected to chronic stress (restraint stress) and monoamines levels were measured by high performance liquid chromatographer (HPLC)-electrochemical detection...
2016: Frontiers in Neural Circuits
MohammadMehdi Kafashan, ShiNung Ching, Ben J A Palanca
Background: The spatiotemporal patterns of correlated neural activity during the transition from wakefulness to general anesthesia have not been fully characterized. Correlation analysis of blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) allows segmentation of the brain into resting-state networks (RSNs), with functional connectivity referring to the covarying activity that suggests shared functional specialization. We quantified the persistence of these correlations following the induction of general anesthesia in healthy volunteers and assessed for a dynamic nature over time...
2016: Frontiers in Neural Circuits
Jasdeep Sabharwal, Robert L Seilheimer, Cameron S Cowan, Samuel M Wu
Retinal ganglion cells (RGCs) are often grouped based on their functional properties. Many of these functional properties, such as receptive field (RF) size, are driven by specific retinal circuits. In this report, we determined the role of the ON bipolar cell (BC) mediated crossover circuitry in shaping the center and surround of OFF RGCs. We recorded from a large population of mouse RGCs using a multielectrode array (MEA) while pharmacologically removing the ON BC-mediated crossover circuit. OFF sustained and transient responses to whole field stimuli are lost under scotopic conditions, but maintained under photopic conditions...
2016: Frontiers in Neural Circuits
Qiang Wang, Wangming Zhang
The emergence of L-DOPA-induced dyskinesia (LID) in patients with Parkinson disease (PD) could be due to maladaptive plasticity of corticostriatal synapses in response to L-DOPA treatment. A series of recent studies has revealed that LID is associated with marked morphological plasticity of striatal dendritic spines, particularly cell type-specific structural plasticity of medium spiny neurons (MSNs) in the striatum. In addition, evidence demonstrating the occurrence of plastic adaptations, including aberrant morphological and functional features, in multiple components of cortico-basal ganglionic circuitry, such as primary motor cortex (M1) and basal ganglia (BG) output nuclei...
2016: Frontiers in Neural Circuits
David A McVea, Timothy H Murphy, Majid H Mohajerani
Cortical sensory systems are active with rich patterns of activity during sleep and under light anesthesia. Remarkably, this activity shares many characteristics with those present when the awake brain responds to sensory stimuli. We review two specific forms of such activity: slow-wave activity (SWA) in the adult brain and spindle bursts in developing brain. SWA is composed of 0.5-4 Hz resting potential fluctuations. Although these fluctuations synchronize wide regions of cortex, recent large-scale imaging has shown spatial details of their distribution that reflect underlying cortical structural projections and networks...
2016: Frontiers in Neural Circuits
David Eriksson
In the last 20 years there has been an increased interest in estimating signals that are sent between neurons and brain areas. During this time many new methods have appeared for measuring those signals. Here we review a wide range of methods for which connected neurons can be identified anatomically, by tracing axons that run between the cells, or functionally, by detecting if the activity of two neurons are correlated with a short lag. The signals that are sent between the neurons are represented by the activity in the neurons that are connected to the target population or by the activity at the corresponding synapses...
2016: Frontiers in Neural Circuits
Yaoyao Hao, Alexa Riehle, Thomas G Brochier
Anatomical studies have demonstrated that distant cortical points are interconnected through long range axon collaterals of pyramidal cells. However, the functional properties of these intrinsic synaptic connections, especially their relationship with the cortical representations of body movements, have not been systematically investigated. To address this issue, we used multielectrode arrays chronically implanted in the motor cortex of two rhesus monkeys to analyze the effects of single-pulse intracortical microstimulation (sICMS) applied at one electrode on the neuronal activities recorded at all other electrodes...
2016: Frontiers in Neural Circuits
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