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https://www.readbyqxmd.com/read/28109667/aberrant-alpha-and-gamma-oscillations-ex-vivo-after-single-application-of-the-nmda-receptor-antagonist-mk-801
#1
Clément E Lemercier, Constance Holman, Zoltan Gerevich
Clinical symptoms of schizophrenia are associated with altered cortical neuronal oscillations in multiple frequency bands such as alpha (7-13Hz) and gamma (30-90Hz) rhythms. NMDA receptor antagonists induce psychotic symptoms in humans and a schizophrenia-like phenotype in animals, suggesting NMDA receptor dysfunction is involved in the generation of many symptoms of the disorder. We investigated the effects of a single intraperitoneal injection of the NMDA receptor antagonist MK-801 in rats, a model of first-episode schizophrenia, on network oscillations recorded ex vivo in the hippocampus and prefrontal cortex...
January 18, 2017: Schizophrenia Research
https://www.readbyqxmd.com/read/28103479/subcortical-source-and-modulation-of-the-narrowband-gamma-oscillation-in-mouse-visual-cortex
#2
Aman B Saleem, Anthony D Lien, Michael Krumin, Bilal Haider, Miroslav Román Rosón, Asli Ayaz, Kimberly Reinhold, Laura Busse, Matteo Carandini, Kenneth D Harris
Primary visual cortex exhibits two types of gamma rhythm: broadband activity in the 30-90 Hz range and a narrowband oscillation seen in mice at frequencies close to 60 Hz. We investigated the sources of the narrowband gamma oscillation, the factors modulating its strength, and its relationship to broadband gamma activity. Narrowband and broadband gamma power were uncorrelated. Increasing visual contrast had opposite effects on the two rhythms: it increased broadband activity, but suppressed the narrowband oscillation...
January 18, 2017: Neuron
https://www.readbyqxmd.com/read/28103471/new-light-on-gamma-oscillations
#3
Cristin G Welle, Diego Contreras
Two papers in this issue of Neuron by Saleem et al. (2017) and Storchi et al. (2017) show that increases in background light intensity trigger proportional increases in narrowband gamma oscillations with a peak at 60 Hz in retina, lateral geniculate, and primary visual cortex of the mouse visual system.
January 18, 2017: Neuron
https://www.readbyqxmd.com/read/28099166/despiking-seeg-signals-reveals-dynamics-of-gamma-band-preictal-activity
#4
Nawel Jmail, Martine Gavaret, F Bartolomei, Christian-G Bénar
Interictal epileptiform discharges, or 'interictal spikes', are the hallmark of epilepsy. Still, there is growing evidence that oscillatory activity-whether in the gamma band (30-120 Hz) or at higher frequencies is another important marker of hyperexcitable tissues. A major difficulty arises from the fact that interictal spikes and oscillations overlap in the frequency domain. This hampers the correct delineation of the cortex producing pathological oscillations by simple filtering. Here, we propose a nonlinear technique for fitting the spike waveform in order to remove it, resulting in a 'despiked' signal...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28092972/tracking-dynamic-interactions-between-structural-and-functional-connectivity-a-tms-eeg-dmri-study
#5
Enrico Amico, Olivier Bodart, Mario Rosanova, Olivia Gosseries, Lizette Heine, Pieter Van Mierlo, Charlotte Martial, Marcello Massimini, Daniele Marinazzo, Steven Laureys
Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography (TMS/hd-EEG), TMS pulses revealed electrophysiological signatures of different cortical modules in health and disease. However, the neural underpinnings of these signatures remain unclear. Here, by applying multimodal analyses of cortical response to TMS recordings and diffusion magnetic resonance imaging (dMRI) tractography, we investigated the relationship between functional and structural features of different cortical modules in a cohort of awake healthy volunteers...
January 16, 2017: Brain Connectivity
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
#6
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/28077711/phase-amplitude-coupling-and-long-range-phase-synchronization-reveal-frontotemporal-interactions-during-visual-working-memory
#7
Jonathan Daume, Thomas Gruber, Andreas K Engel, Uwe Friese
: It has been suggested that cross-frequency phase-amplitude coupling (PAC), particularly in temporal brain structures, serves as a neural mechanism for coordinated working memory storage. In this magnetoencephalography study, we show that during visual working memory maintenance, temporal cortex regions, which exhibit enhanced PAC, interact with prefrontal cortex via enhanced low-frequency phase synchronization. Healthy human participants were engaged in a visual delayed match-to-sample task with pictures of natural objects...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28076421/oscillatory-dynamics-supporting-semantic-cognition-meg-evidence-for-the-contribution-of-the-anterior-temporal-lobe-hub-and-modality-specific-spokes
#8
Giovanna Mollo, Piers L Cornelissen, Rebecca E Millman, Andrew W Ellis, Elizabeth Jefferies
The "hub and spoke model" of semantic representation suggests that the multimodal features of objects are drawn together by an anterior temporal lobe (ATL) "hub", while modality-specific "spokes" capture perceptual/action features. However, relatively little is known about how these components are recruited through time to support object identification. We used magnetoencephalography to measure neural oscillations within left ATL, lateral fusiform cortex (FC) and central sulcus (CS) during word-picture matching at different levels of specificity (employing superordinate vs...
2017: PloS One
https://www.readbyqxmd.com/read/28069543/brain-oscillations-differentially-encode-noxious-stimulus-intensity-and-pain-intensity
#9
Moritz M Nickel, Elisabeth S May, Laura Tiemann, Paul Schmidt, Martina Postorino, Son Ta Dinh, Joachim Gross, Markus Ploner
Noxious stimuli induce physiological processes which commonly translate into pain. However, under certain conditions, pain intensity can substantially dissociate from stimulus intensity, e.g. during longer-lasting pain in chronic pain syndromes. How stimulus intensity and pain intensity are differentially represented in the human brain is, however, not yet fully understood. We therefore used electroencephalography (EEG) to investigate the cerebral representation of noxious stimulus intensity and pain intensity during 10min of painful heat stimulation in 39 healthy human participants...
January 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28067903/modulation-of-excitation-on-parvalbumin-interneurons-by-neuroligin-3-regulates-the-hippocampal-network
#10
Jai S Polepalli, Hemmings Wu, Debanjan Goswami, Casey H Halpern, Thomas C Südhof, Robert C Malenka
Hippocampal network activity is generated by a complex interplay between excitatory pyramidal cells and inhibitory interneurons. Although much is known about the molecular properties of excitatory synapses on pyramidal cells, comparatively little is known about excitatory synapses on interneurons. Here we show that conditional deletion of the postsynaptic cell adhesion molecule neuroligin-3 in parvalbumin interneurons causes a decrease in NMDA-receptor-mediated postsynaptic currents and an increase in presynaptic glutamate release probability by selectively impairing the inhibition of glutamate release by presynaptic Group III metabotropic glutamate receptors...
January 9, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28049075/abnormal-brain-oscillations-persist-after-recovery-from-bipolar-depression
#11
P Canali, S Casarotto, M Rosanova, G Sferrazza-Papa, A G Casali, O Gosseries, M Massimini, E Smeraldi, C Colombo, F Benedetti
When directly perturbed in healthy subjects, premotor cortical areas generate electrical oscillations in the beta range (20-40Hz). In schizophrenia, major depressive disorder and bipolar disorder (BD), these oscillations are markedly reduced, in terms of amplitude and frequency. However, it still remains unclear whether these abnormalities can be modulated over time, or if they can be still observed after treatment. Here, we employed transcranial magnetic stimulation (TMS) combined with EEG to assess the frontal oscillatory activity in eighteen BD patients before/after antidepressant treatments (sleep deprivation and light therapy), relative to nine healthy controls...
December 27, 2016: European Psychiatry: the Journal of the Association of European Psychiatrists
https://www.readbyqxmd.com/read/28039374/removal-of-perineuronal-nets-unlocks-juvenile-plasticity-through-network-mechanisms-of-decreased-inhibition-and-increased-gamma-activity
#12
Kristian Kinden Lensjø, Mikkel Elle Lepperød, Gunnar Dick, Torkel Hafting, Marianne Fyhn
: Perineuronal nets (PNNs) are extracellular matrix structures mainly enwrapping parvalbumin-expressing inhibitory neurons. The assembly of PNNs coincides with the end of the period of heightened visual cortex plasticity in juveniles, while removal of PNNs in adults reopens for plasticity. The mechanisms underlying this phenomenon remain elusive. We have used chronic electrophysiological recordings to investigate accompanying electrophysiological changes to activity-dependent plasticity, and we report on novel mechanisms involved in both induced and critical period plasticity...
December 30, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28032676/hippocampal-gamma-band-synchrony-and-pupillary-responses-index-memory-during-visual-search
#13
Rodrigo Montefusco-Siegmund, Timothy K Leonard, Kari L Hoffman
Memory for scenes is supported by the hippocampus, among other interconnected structures, but the neural mechanisms related to this process are not well understood. To assess the role of the hippocampus in memory-guided scene search, we recorded local field potentials and multi-unit activity from the hippocampus of macaques as they performed goal-directed search tasks using natural scenes. We additionally measured pupil size during scene presentation, which in humans is modulated by recognition memory. We found that both pupil dilation and search efficiency accompanied scene repetition, thereby indicating memory for scenes...
December 29, 2016: Hippocampus
https://www.readbyqxmd.com/read/28031400/spinal-cord-direct-current-stimulation-differentially-modulates-neuronal-activity-in-the-dorsal-and-ventral-spinal-cord
#14
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/28029717/time-course-of-gamma-band-oscillation-associated-with-face-processing-in-the-inferior-occipital-gyrus-and-fusiform-gyrus-a-combined-fmri-and-meg-study
#15
Shota Uono, Wataru Sato, Takanori Kochiyama, Yasutaka Kubota, Reiko Sawada, Sayaka Yoshimura, Motomi Toichi
Debate continues over whether the inferior occipital gyrus (IOG) or the fusiform gyrus (FG) represents the first stage of face processing and what role these brain regions play. We investigated this issue by combining functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) in normal adults. Participants passively observed upright and inverted faces and houses. First, we identified the IOG and FG as face-specific regions using fMRI. We applied beamforming source reconstruction and time-frequency analysis to MEG source signals to reveal the time course of gamma-band activations in these regions...
December 28, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/28018202/further-work-on-the-shaping-of-cortical-development-and-function-by-synchrony-and-metabolic-competition
#16
James J Wright, Paul D Bourke
This paper furthers our attempts to resolve two major controversies-whether gamma synchrony plays a role in cognition, and whether cortical columns are functionally important. We have previously argued that the configuration of cortical cells that emerges in development is that which maximizes the magnitude of synchronous oscillation and minimizes metabolic cost. Here we analyze the separate effects in development of minimization of axonal lengths, and of early Hebbian learning and selective distribution of resources to growing synapses, by showing in simulations that these effects are partially antagonistic, but their interaction during development produces accurate anatomical and functional properties for both columnar and non-columnar cortex...
2016: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28012274/activity-dependent-switch-of-gabaergic-inhibition-into-glutamatergic-excitation-in-astrocyte-neuron-networks
#17
Gertrudis Perea, Ricardo Gómez, Sara Mederos, Ana Covelo, Jesús J Ballesteros, Laura Schlosser, Alicia Hernández-Vivanco, Mario Martín-Fernández, Ruth Quintana, Abdelrahman Rayan, Adolfo Díez, Marco Fuenzalida, Amit Agarwal, Dwight E Bergles, Bernhard Bettler, Denise Manahan-Vaughan, Eduardo D Martín, Frank Kirchhoff, Alfonso Araque
Interneurons are critical for proper neural network function and can activate Ca(2+) signaling in astrocytes. However, the impact of the interneuron-astrocyte signaling into neuronal network operation remains unknown. Using the simplest hippocampal Astrocyte-Neuron network, i.e., GABAergic interneuron, pyramidal neuron, single CA3-CA1 glutamatergic synapse, and astrocytes, we found that interneuron-astrocyte signaling dynamically affected excitatory neurotransmission in an activity- and time-dependent manner, and determined the sign (inhibition vs potentiation) of the GABA-mediated effects...
December 24, 2016: ELife
https://www.readbyqxmd.com/read/28009257/interneuronal-mechanisms-of-hippocampal-theta-oscillation-in-a-full-scale-model-of-the-rodent-ca1-circuit
#18
Marianne J Bezaire, Ivan Raikov, Kelly Burk, Dhrumil Vyas, Ivan Soltesz
The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation...
December 23, 2016: ELife
https://www.readbyqxmd.com/read/28003411/dorsal-versus-ventral-differences-in-fast-up-state-associated-oscillations-in-the-medial-prefrontal-cortex-mpfc-of-the-urethane-anaesthetised-rat
#19
Sabine Gretenkord, Adrian Rees, Miles A Whittington, Sarah E Gartside, Fiona E N LeBeau
Cortical slow oscillations (0.1 - 1 Hz), which may play a role in memory consolidation, are a hallmark of non-rapid eye movement (NREM) sleep and also occur under anaesthesia. During slow oscillations the neuronal network generates faster oscillations on the active Up-states and these nested oscillations are particularly prominent in the PFC. In rodents the mPFC consists of several subregions: anterior cingulate cortex (ACC), prelimbic (PrL), infralimbic (IL) and dorsal peduncular cortices (DP). Although each region has a distinct anatomy and function, it is not known whether slow or fast network oscillations differ between subregions in vivo...
December 21, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27999553/beta-gamma-oscillations-and-event-related-potentials-indicate-aberrant-multisensory-processing-in-schizophrenia
#20
Johanna Balz, Yadira Roa Romero, Julian Keil, Martin Krebber, Michael Niedeggen, Jürgen Gallinat, Daniel Senkowski
Recent behavioral and neuroimaging studies have suggested multisensory processing deficits in patients with schizophrenia (SCZ). Thus far, the neural mechanisms underlying these deficits are not well understood. Previous studies with unisensory stimulation have shown altered neural oscillations in SCZ. As such, altered oscillations could contribute to aberrant multisensory processing in this patient group. To test this assumption, we conducted an electroencephalography (EEG) study in 15 SCZ and 15 control participants in whom we examined neural oscillations and event-related potentials (ERPs) in the sound-induced flash illusion (SIFI)...
2016: Frontiers in Psychology
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