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https://www.readbyqxmd.com/read/28197543/impedance-spectrum-in-cortical-tissue-implications-for-propagation-of-lfp-signals-on-the-microscopic-level
#1
Stéphanie Miceli, Torbjørn V Ness, Gaute T Einevoll, Dirk Schubert
Brain research investigating electrical activity within neural tissue is producing an increasing amount of physiological data including local field potentials (LFPs) obtained via extracellular in vivo and in vitro recordings. In order to correctly interpret such electrophysiological data, it is vital to adequately understand the electrical properties of neural tissue itself. An ongoing controversy in the field of neuroscience is whether such frequency-dependent effects bias LFP recordings and affect the proper interpretation of the signal...
January 2017: ENeuro
https://www.readbyqxmd.com/read/28196142/moderate-injury-in-motor-sensory-cortex-causes-behavioral-deficits-accompanied-by-electrophysiological-changes-in-mice-adulthood
#2
Wei Ouyang, Qichao Yan, Yu Zhang, Zhiheng Fan
Moderate traumatic brain injury (TBI) in children often happen when there's a sudden blow to the frontal bone, end with long unconscious which can last for hours and progressive cognitive deficits. However, with regard to the influences of moderate TBI during children adulthood, injury-induced alterations of locomotive ability, long-term memory performance, and hippocampal electrophysiological firing changes have not yet been fully identified. In this study, lateral fluid percussion (LFP) method was used to fabricate moderate TBI in motor and somatosensory cortex of the 6-weeks-old mice...
2017: PloS One
https://www.readbyqxmd.com/read/28191033/algorithm-and-software-to-automatically-identify-latency-and-amplitude-features-of-local-field-potentials-recorded-in-electrophysiological-investigation
#3
Maria Rubega, Claudia Cecchetto, Stefano Vassanelli, Giovanni Sparacino
BACKGROUND: Local field potentials (LFPs) evoked by sensory stimulation are particularly useful in electrophysiological research. For instance, spike timing and current transmembrane current flow estimated from LFPs recorded in the barrel cortex in rats and mice are exploited to investigate how the brain represents sensory stimuli. Recent improvements in microelectrodes technology enable neuroscientists to acquire a great amount of LFPs during the same experimental session, calling for algorithms for their quantitative automatic analysis...
2017: Source Code for Biology and Medicine
https://www.readbyqxmd.com/read/28128335/repeated-nicotine-strengthens-gamma-oscillations-in-the-prefrontal-cortex-and-improves-visual-attention
#4
Lezio S Bueno-Junior, Nicholas W Simon, Meredyth A Wegener, Bita Moghaddam
Nicotine has strong addictive as well as procognitive properties. While a large body of research on nicotine continues to inform us about mechanisms related to its reinforcing effects, less is known about clinically relevant mechanisms that subserve its cognitive enhancing properties. Understanding the latter is critical for developing optimal strategies for treating cognitive deficits. The primary brain region implicated in cognitive functions improved by nicotine is the prefrontal cortex (PFC). Here we assessed the impact of nicotine on unit activity and local field potential (LFP) oscillations in the PFC of behaving rats...
January 27, 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/28116750/relationship-between-cortical-state-and-spiking-activity-in-lateral-geniculate-nucleus-of-anaesthetised-marmosets
#5
Alexander N J Pietersen, Soon Keen Cheong, Brandon Munn, Pulin Gong, Paul R Martin, Samuel G Solomon
The major afferent cortical pathway in the visual system passes through the dorsal lateral geniculate nucleus (LGN), where nerve signals originating in the eye can first interact with brain circuits regulating visual processing, vigilance, and attention. Here we asked how on-going and visually driven activity in magnocellular (M), parvocellular (P), and koniocellular (K) layers of the LGN are related to cortical state. We recorded extracellular spiking activity in the LGN simultaneously with local field potentials (LFP) in primary visual cortex, in sufentanil-anesthetized marmoset monkeys...
January 24, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28113981/a-method-for-removal-of-deep-brain-stimulation-artifact-from-local-field-potentials
#6
Xing Qian, Yue Chen, Yuan Feng, Bozhi Ma, Hongwei Hao, Luming Li
This article presents a signal processing method for the electrophysiology simultaneously recorded during deep brain stimulation (DBS) as a research tool. Regarding the local field potential (LFP) signals recorded during stimulation, a novel method was proposed for removal of stimulation artifacts caused by the much stronger stimulating pulse compared to typical LFP. This artifact suppression method was tested and evaluated in an in vitro situation. The results indicate that the stimulation artifacts are well suppressed by this method...
September 26, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28113942/decoding-local-field-potentials-for-neural-interfaces
#7
Andrew Jackson, Thomas M Hall
The stability and frequency content of the local field potentials (LFP) offer key advantages for long-term, low-power neural interfaces. However, interpreting LFPs may require new signal processing techniques which should be informed by a scientific understanding of how these recordings arise from the coordinated activity of underlying neuronal populations. We review current approaches to decoding LFPs for Brain-Machine Interface (BMI) applications, and suggest several directions for future research. To facilitate an improved understanding of the relationship between LFPs and spike activity, we share a dataset of multielectrode recordings from monkey motor cortex, and describe two unsupervised analysis methods we have explored for extracting a low-dimensional feature space that is amenable to biomimetic decoding and biofeedback training...
November 14, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28100654/dissociation-between-sustained-single-neuron-spiking-%C3%AE-rhythmicity-and-transient-%C3%AE-lfp-oscillations-in-primate-motor-cortex
#8
Michael Everett Rule, Carlos E Vargas-Irwin, John P Donoghue, Wilson Truccolo
Determining the relationship between single-neuron spiking and transient (~20 Hz) beta local field potential (β-LFP) oscillations is an important step for understanding the role of these oscillations in motor cortex. We show that while motor cortex firing rates and beta spiking rhythmicity remain sustained during steady-state movement preparation periods, β-LFP oscillations emerge, in contrast, as short transient events. Single-neuron mean firing rates within and outside transient β-LFP events showed no differences, and no consistent correlation was found between the beta oscillations' amplitude and firing rates, as was the case for movement and visual-cue related β-LFP suppression...
January 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28088666/vocal-emotion-decoding-in-the-subthalamic-nucleus-an-intracranial-erp-study-in-parkinson-s-disease
#9
Julie Péron, Olivier Renaud, Claire Haegelen, Lucas Tamarit, Valérie Milesi, Jean-François Houvenaghel, Thibaut Dondaine, Marc Vérin, Paul Sauleau, Didier Grandjean
Using intracranial local field potential (LFP) recordings in patients with Parkinson's disease (PD) undergoing deep brain stimulation (DBS), we explored the electrophysiological activity of the subthalamic nucleus (STN) in response to emotional stimuli in the auditory modality. Previous studies focused on the influence of visual stimuli. To this end, we recorded LFPs within the STN in response to angry, happy, and neutral prosodies in 13 patients with PD who had just undergone implantation of DBS electrodes...
January 12, 2017: Brain and Language
https://www.readbyqxmd.com/read/28087359/the-effect-of-nmda-r-antagonism-on-simultaneously-acquired-local-field-potentials-and-tissue-oxygen-levels-in-the-brains-of-freely-moving-rats
#10
John Kealy, Sean Commins, John P Lowry
Non-competitive NMDA receptor antagonists are known to induce psychosis-like symptoms in rodents. Administration of such compounds cause behavioural effects such as memory impairment and hyperlocomotion. Additionally, drugs such as phencyclidine (PCP), ketamine and MK-801 all cause distinctive increases in striatal local field potential (LFP) in the high frequency oscillation (HFO) band in the power spectrum (140-180 Hz). Amperometric sensors provide a means to measure tissue oxygen (tO2; a BOLD-like signal) in the brains of freely-moving rats while simultaneously acquiring LFP using the same electrode...
January 11, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28077288/micro-endoscopic-system-for-functional-assessment-of-neural-circuits-in-deep-brain-regions-simultaneous-optical-and-electrical-recordings-of-auditory-responses-in-mouse-s-inferior-colliculus
#11
Hidetaka Yashiro, Ichiro Nakahara, Kazuo Funabiki, Hiroshi Riquimaroux
In vivo Ca(2+) imaging is a powerful method for the functional assessment of neural circuits. Although multi-photon excitation fluorescence microscopy has been widely used, observation of circuits in deep brain regions remains challenging. Recently, observing these deep regions has become possible via an endoscope consisting of an optical fiber bundle or gradient-index lens. We have designed a micro-endoscope system that enables simultaneous optical recording of fluorescence and electrical recording of neural activity...
January 7, 2017: Neuroscience Research
https://www.readbyqxmd.com/read/28074856/local-field-potentials-primarily-reflect-inhibitory-neuron-activity-in-human-and-monkey-cortex
#12
Bartosz Teleńczuk, Nima Dehghani, Michel Le Van Quyen, Sydney S Cash, Eric Halgren, Nicholas G Hatsopoulos, Alain Destexhe
The local field potential (LFP) is generated by large populations of neurons, but unitary contribution of spiking neurons to LFP is not well characterised. We investigated this contribution in multi-electrode array recordings from human and monkey neocortex by examining the spike-triggered LFP average (st-LFP). The resulting st-LFPs were dominated by broad spatio-temporal components due to ongoing activity, synaptic inputs and recurrent connectivity. To reduce the spatial reach of the st-LFP and observe the local field related to a single spike we applied a spatial filter, whose weights were adapted to the covariance of ongoing LFP...
January 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28069927/impact-of-altered-cholinergic-tones-on-the-neurovascular-coupling-response-to-whisker-stimulation
#13
Clotilde Lecrux, Claire H Sandoe, Sujaya Neupane, Pascal Kropf, Xavier Toussay, Xin-Kang Tong, María Lacalle-Aurioles, Amir Shmuel, Edith Hamel
Brain imaging techniques that use vascular signals to map changes in neuronal activity rely on the coupling between electrophysiology and hemodynamics, a phenomenon referred to as "neurovascular coupling" (NVC). It is unknown whether this relationship remains reliable under altered brain states associated with acetylcholine (ACh) levels, such as attention and arousal and in pathological conditions such as Alzheimer's disease. We therefore assessed the effects of varying ACh tone on whisker-evoked NVC responses in rat barrel cortex, measured by cerebral blood flow (CBF) and neurophysiological recordings (local field potentials, LFPs)...
February 8, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28047631/we-fg-206-04-comprehensive-evaluation-of-left-ventricular-lv-filling-and-ejection-using-high-frame-rate-cine-mr-imaging-key-technical-and-methodological-requirements
#14
J Zhang, B Cheong, A Pednekar, C Arena, D Dees, R Muthupillai
PURPOSE: Unlike echocardiography which can quantify both LV filling and ejection, cine steady state free precession sequence (SSFP)-despite its high intrinsic signal and contrast to noise ratio, accuracy and precision of volume measurements-, is mostly relegated to quantifying LV ejection. The steady-state requirement typically constrains SSFP sequence to a breathhold (and limited temporal resolution). We describe: (a) free breathing cine SSFP approach that meets the SS requirement allowing high frame rate acquisition, (b) two MRI indices based on time-LV volume (TV) change during filling and compare against echocardiagraphic diastolic index (E/A ratio), and (c) evaluate the effect of temporal resolution on: LV volumes; ejection and filling rates; and normalized indices of systolic and diastolic function...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28031400/spinal-cord-direct-current-stimulation-differentially-modulates-neuronal-activity-in-the-dorsal-and-ventral-spinal-cord
#15
Weiguo Song, John H Martin
Spinal cord direct current stimulation (sDCS) has the potential for promoting motor function after injury through its modulatory actions on sensory processing, reflex functions, the motor cortex (M1) motor map, and motor output. Here we addressed systems-level mechanisms underlying sDCS neuromodulation of spinal circuits activated by M1 and peripheral forelimb electrical stimulation in anesthetized healthy rats. We determined the effects of cathodal and anodal sDCS (c- and a-sDCS) on local field potentials (LFP) and single-unit activity recorded at 32 sites simultaneously within the 6th cervical segment using a silicon multi-electrode array...
December 28, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28029630/design-of-a-closed-loop-bidirectional-brain-machine-interface-system-with-energy-efficient-neural-feature-extraction-and-pid-control
#16
Xilin Liu, Milin Zhang, Andrew G Richardson, Timothy H Lucas, Jan Van der Spiegel
This paper presents a bidirectional brain machine interface (BMI) microsystem designed for closed-loop neuroscience research, especially experiments in freely behaving animals. The system-on-chip (SoC) consists of 16-channel neural recording front-ends, neural feature extraction units, 16-channel programmable neural stimulator back-ends, in-channel programmable closed-loop controllers, global analog-digital converters (ADC), and peripheral circuits. The proposed neural feature extraction units includes 1) an ultra low-power neural energy extraction unit enabling a 64-step natural logarithmic domain frequency tuning, and 2) a current-mode action potential (AP) detection unit with time-amplitude window discriminator...
December 16, 2016: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28018180/local-field-potentials-myths-and-misunderstandings
#17
REVIEW
Oscar Herreras
The intracerebral local field potential (LFP) is a measure of brain activity that reflects the highly dynamic flow of information across neural networks. This is a composite signal that receives contributions from multiple neural sources, yet interpreting its nature and significance may be hindered by several confounding factors and technical limitations. By and large, the main factor defining the amplitude of LFPs is the geometry of the current sources, over and above the degree of synchronization or the properties of the media...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28017962/sirt1-plays-a-neuroprotective-role-in-traumatic-brain-injury-in-rats-via-inhibiting-the-p38-mapk-pathway
#18
Hong Yang, Zheng-Tao Gu, Li Li, Mac Maegele, Bi-Ying Zhou, Feng Li, Ming Zhao, Ke-Sen Zhao
Traumatic brain injury (TBI) is a major cause of disability and death in patients who experience a traumatic injury. Mitochondrial dysfunction is one of the main factors contributing to secondary injury in TBI-associated brain damage. Evidence of compromised mitochondrial function after TBI has been, but the molecular mechanisms underlying the pathogenesis of TBI are not well understood. Silent information regulator family protein 1 (SIRT1), a member of the NAD(+)-dependent protein deacetylases, has been shown to exhibit neuroprotective activities in animal models of various pathologies, including ischemic brain injury, subarachnoid hemorrhage and several neurodegenerative diseases...
December 26, 2016: Acta Pharmacologica Sinica
https://www.readbyqxmd.com/read/28007587/astrocytic-gap-junction-blockade-markedly-increases-extracellular-potassium-without-causing-seizures-in-the-mouse-neocortex
#19
Paolo Bazzigaluppi, Iliya Weisspapir, Bojana Stefanovic, Luc Leybaert, Peter L Carlen
Extracellular potassium concentration, [K(+)]o, is a major determinant of neuronal excitability. In the healthy brain, [K(+)]o levels are tightly controlled. During seizures, [K(+)]o increases up to 15mM and is thought to cause seizures due to its depolarizing effect. Although astrocytes have been suggested to play a key role in the redistribution (or spatial buffering) of excess K(+) through Connexin-43 (Cx43)-based Gap Junctions (GJs), the relation between this dynamic regulatory process and seizure generation remains unknown...
December 20, 2016: Neurobiology of Disease
https://www.readbyqxmd.com/read/27999534/striatal-dopaminergic-innervation-regulates-subthalamic-beta-oscillations-and-cortical-subcortical-coupling-during-movements-preliminary-evidence-in-subjects-with-parkinson-s-disease
#20
Andrea Canessa, Nicolò G Pozzi, Gabriele Arnulfo, Joachim Brumberg, Martin M Reich, Gianni Pezzoli, Maria F Ghilardi, Cordula Matthies, Frank Steigerwald, Jens Volkmann, Ioannis U Isaias
Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the functional interaction of cortical and subcortical brain areas during movement and the relative contribution of dopaminergic striatal innervation remains unclear. We recorded local field potential (LFP) activity from the subthalamic nucleus (STN) and high-density electroencephalography (EEG) signals in four patients with Parkinson's disease (PD) off dopaminergic medication during a multi-joint motor task performed with their dominant and non-dominant hand...
2016: Frontiers in Human Neuroscience
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