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https://www.readbyqxmd.com/read/28072877/motor-cortex-theta-and-gamma-architecture-in-young-adult-appsweps1de9-alzheimer-mice
#1
Anna Papazoglou, Julien Soos, Andreas Lundt, Carola Wormuth, Varun Raj Ginde, Ralf Müller, Christina Henseler, Karl Broich, Kan Xie, Britta Haenisch, Dan Ehninger, Marco Weiergräber
Alzheimer's disease (AD) is a multifactorial disorder leading to progressive memory loss and eventually death. In this study, an APPswePS1dE9 AD mouse model has been analyzed for motor cortex theta, beta and gamma frequency alterations using computerized 3D stereotaxic electrode positioning and implantable video-EEG radiotelemetry to perform long-term M1 recordings from both genders considering age, circadian rhythm and activity status of experimental animals. We previously demonstrated that APPswePS1dE9 mice exibit complex alterations in hippocampal frequency power and another recent investigation reported a global increase of alpha, beta and gamma power in APPswePS1dE9 in females of 16-17 weeks of age...
2017: PloS One
https://www.readbyqxmd.com/read/28032686/impairments-in-spatial-representations-and-rhythmic-coordination-of-place-cells-in-the-3xtg-mouse-model-of-alzheimer-s-disease
#2
Alexandra J Mably, Brian J Gereke, Dylan T Jones, Laura Lee Colgin
Alzheimer's disease (AD) is an irreversible and highly progressive neurodegenerative disease. Clinically, patients with AD display impairments in episodic and spatial memory. However, the underlying neuronal dysfunctions that result in these impairments remain poorly understood. The hippocampus is crucial for spatial and episodic memory, and thus we tested the hypothesis that abnormal neuronal representations of space in the hippocampus contribute to memory deficits in AD. To test this hypothesis, we recorded spikes from place cells in hippocampal subfield CA1, together with corresponding rhythmic activity in local field potentials, in the 3xTg AD mouse model...
December 29, 2016: Hippocampus
https://www.readbyqxmd.com/read/28009257/interneuronal-mechanisms-of-hippocampal-theta-oscillation-in-a-full-scale-model-of-the-rodent-ca1-circuit
#3
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/27939920/gamma-glutamyl-transferase-and-atrial-fibrillation-in-patients-with-coronary-artery-disease
#4
Gjin Ndrepepa, Erion Xhepa, Roisin Colleran, Siegmund Braun, Salvatore Cassese, Massimiliano Fusaro, Karl-Ludwig Laugwitz, Adnan Kastrati
BACKGROUND: The association between gamma-glutamyl transferase (GGT) and atrial fibrillation (AF) in patients with coronary artery disease (CAD) is uncertain. METHODS: This study included 5501 consecutive patients with CAD, all of whom had baseline GGT measurements available. The primary endpoint was presence of AF. RESULTS: Overall 809 patients (14.7%) had AF on hospital admission. Patients with AF had significantly higher GGT activity compared with patients in sinus rhythm (median [25th-75th percentile]: 52...
December 6, 2016: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/27929004/gamma-frequency-entrainment-attenuates-amyloid-load-and-modifies-microglia
#5
Hannah F Iaccarino, Annabelle C Singer, Anthony J Martorell, Andrii Rudenko, Fan Gao, Tyler Z Gillingham, Hansruedi Mathys, Jinsoo Seo, Oleg Kritskiy, Fatema Abdurrob, Chinnakkaruppan Adaikkan, Rebecca G Canter, Richard Rueda, Emery N Brown, Edward S Boyden, Li-Huei Tsai
Changes in gamma oscillations (20-50 Hz) have been observed in several neurological disorders. However, the relationship between gamma oscillations and cellular pathologies is unclear. Here we show reduced, behaviourally driven gamma oscillations before the onset of plaque formation or cognitive decline in a mouse model of Alzheimer's disease. Optogenetically driving fast-spiking parvalbumin-positive (FS-PV)-interneurons at gamma (40 Hz), but not other frequencies, reduces levels of amyloid-β (Aβ)1-40 and Aβ 1-42 isoforms...
December 7, 2016: Nature
https://www.readbyqxmd.com/read/27927782/modeling-fast-and-slow-gamma-oscillations-with-interneurons-of-different-subtype
#6
Stephen Keeley, André A Fenton, John Rinzel
Experimental and theoretical studies demonstrate that neuronal gamma oscillations crucially depend on interneurons, but current models do not consider the diversity of known interneuron subtypes. Moreover, in CA1 of the hippocampus, experimental evidence indicates the presence of multiple gamma oscillators, two of which may be coordinated by differing interneuron populations. Here, we show that models of networks with competing interneuron populations with different post-synaptic effects are sufficient to generate, within CA1, distinct oscillatory regimes...
December 7, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27922595/memories-of-opiate-withdrawal-emotional-states-correlate-with-specific-gamma-oscillations-in-the-nucleus-accumbens
#7
Cyril Dejean, Mathieu Sitko, Paul Girardeau, Amine Bennabi, Stéphanie Caillé, Martine Cador, Thomas Boraud, Catherine Le Moine
Affective memories associated with the negative emotional state experienced during opiate withdrawal are central in maintaining drug-taking, seeking and relapse. Nucleus accumbens (NAC) is a key structure both for acute withdrawal and withdrawal memories reactivation, however NAC neuron coding properties underpinning the expression of these memories remain largely unknown. Here we aimed at deciphering the role of NAC neurons in the encoding and retrieval of opiate withdrawal memory. Chronic single neuron and local field potentials recordings were performed in morphine-dependent rats and placebo-controls...
December 6, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/27886711/eeg-epochs-with-less-alpha-rhythm-improve-discrimination-of-mild-alzheimer-s
#8
Paulo A M Kanda, Eliezyer F Oliveira, Francisco J Fraga
BACKGROUND AND OBJECTIVE: Eyes-closed-awake electroencephalogram (EEG) is a useful tool in the diagnosis of Alzheimer's. However, there is eyes-closed-awake EEG with dominant or rare alpha rhythm. In this paper, we show that random selection of EEG epochs disregarding the alpha rhythm will lead to bias concerning EEG-based Alzheimer's Disease diagnosis. METHODS: We compared EEG epochs with more than 30% and with less than 30% alpha rhythm of mild Alzheimer's Disease patients and healthy elderly...
January 2017: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/27881788/brain-network-mechanisms-underlying-motor-enhancement-by-transcranial-entrainment-of-gamma-oscillations
#9
Marius Moisa, Rafael Polania, Marcus Grueschow, Christian C Ruff
: Gamma and beta oscillations are routinely observed in motor-related brain circuits during movement preparation and execution. Entrainment of gamma or beta oscillations via transcranial alternating current stimulation (tACS) over primary motor cortex (M1) has opposite effects on motor performance, suggesting a causal role of these brain rhythms for motor control. However, it is largely unknown which brain mechanisms characterize these changes in motor performance brought about by tACS...
November 23, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27830753/lucky-rhythms-in-orbitofrontal-cortex-bias-gambling-decisions-in-humans
#10
Pierre Sacré, Matthew S D Kerr, Kevin Kahn, Jorge Gonzalez-Martinez, Juan Bulacio, Hyun-Joo Park, Matthew A Johnson, Susan Thompson, Jaes Jones, Vikram S Chib, John T Gale, Sridevi V Sarma
It is well established that emotions influence our decisions, yet the neural basis of this biasing effect is not well understood. Here we directly recorded local field potentials from the OrbitoFrontal Cortex (OFC) in five human subjects performing a financial decision-making task. We observed a striking increase in gamma-band (36-50 Hz) oscillatory activity that reflected subjects' decisions to make riskier choices. Additionally, these gamma rhythms were linked back to mismatched expectations or "luck" occurring in past trials...
November 10, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27802274/topology-cross-frequency-and-same-frequency-band-interactions-shape-the-generation-of-phase-amplitude-coupling-in-a-neural-mass-model-of-a-cortical-column
#11
Roberto C Sotero
Phase-amplitude coupling (PAC), a type of cross-frequency coupling (CFC) where the phase of a low-frequency rhythm modulates the amplitude of a higher frequency, is becoming an important indicator of information transmission in the brain. However, the neurobiological mechanisms underlying its generation remain undetermined. A realistic, yet tractable computational model of the phenomenon is thus needed. Here we analyze a neural mass model of a cortical column, comprising fourteen neuronal populations distributed across four layers (L2/3, L4, L5 and L6)...
November 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27790169/large-scale-functional-brain-networks-underlying-temporal-integration-of-audio-visual-speech-perception-an-eeg-study
#12
G Vinodh Kumar, Tamesh Halder, Amit K Jaiswal, Abhishek Mukherjee, Dipanjan Roy, Arpan Banerjee
Observable lip movements of the speaker influence perception of auditory speech. A classical example of this influence is reported by listeners who perceive an illusory (cross-modal) speech sound (McGurk-effect) when presented with incongruent audio-visual (AV) speech stimuli. Recent neuroimaging studies of AV speech perception accentuate the role of frontal, parietal, and the integrative brain sites in the vicinity of the superior temporal sulcus (STS) for multisensory speech perception. However, if and how does the network across the whole brain participates during multisensory perception processing remains an open question...
2016: Frontiers in Psychology
https://www.readbyqxmd.com/read/27764592/selective-interareal-synchronization-through-gamma-frequency-differences-and-slower-rhythm-gamma-phase-reset
#13
Thomas Burwick, Alexandros Bouras
The communication-through-coherence (CTC) hypothesis states that a sending group of neurons will have a particularly strong effect on a receiving group if both groups oscillate in a phase-locked ("coherent") manner (Fries, 2005, 2015). Here, we consider a situation with two visual stimuli, one in the focus of attention and the other distracting, resulting in two sites of excitation at an early cortical area that project to a common site in a next area. Taking a modeler's perspective, we confirm the workings of a mechanism that was proposed by Bosman et al...
October 20, 2016: Neural Computation
https://www.readbyqxmd.com/read/27718535/the-rhythm-of-the-executive-gate-of-speech-subthalamic-low-frequency-oscillations-increase-during-verbal-generation
#14
Lars Wojtecki, Saskia Elben, Jan Vesper, Alfons Schnitzler
We investigated neurophysiological mechanisms of subthalamic nucleus involvement in verbal fluency by means of a verbal generation task. The subthalamic nucleus is thought to act as a behavioural go/no-go instance by means of oscillatory communication in theta band with the prefrontal cortex. Because subthalamic alpha-theta frequency stimulation has been shown to exert beneficial effects on verbal fluency in Parkinson's disease, we hypothesized that an alpha-theta oscillatory network involving the subthalamic nucleus underlies verbal generation task performance as a gating instance for speech execution...
October 8, 2016: European Journal of Neuroscience
https://www.readbyqxmd.com/read/27713698/stress-assessment-by-prefrontal-relative-gamma
#15
Jesus Minguillon, Miguel A Lopez-Gordo, Francisco Pelayo
Stress assessment has been under study in the last years. Both biochemical and physiological markers have been used to measure stress level. In neuroscience, several studies have related modification of stress level to brain activity changes in limbic system and frontal regions, by using non-invasive techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). In particular, previous studies suggested that the exhibition or inhibition of certain brain rhythms in frontal cortical areas indicates stress...
2016: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/27693609/neural-oscillations-as-a-bridge-between-glutamatergic-system-and-emotional-behaviors-in-simulated-microgravity-induced-mice
#16
Xueliang Shang, Bo Xu, Qun Li, Baohui Zhai, Xiaxia Xu, Tao Zhang
This study aims to investigate if neural oscillations can play a role as a bridge between the alteration of glutamatergic system and emotional behaviors in simulated microgravity (SM) mice. Adult male C57BL/6J mice were randomly divided into two groups: SM and control groups. The animal model was established by hindlimb unloading (HU). The mice were exposed to HU continued for 14days. Weight and sucrose consumption were measured. The degree of anxious and depressive was evaluated by Open field test and Elevated plus maze test...
September 28, 2016: Behavioural Brain Research
https://www.readbyqxmd.com/read/27667008/gamma-rhythmic-gain-modulation
#17
Jianguang Ni, Thomas Wunderle, Christopher Murphy Lewis, Robert Desimone, Ilka Diester, Pascal Fries
Cognition requires the dynamic modulation of effective connectivity, i.e., the modulation of the postsynaptic neuronal response to a given input. If postsynaptic neurons are rhythmically active, this might entail rhythmic gain modulation, such that inputs synchronized to phases of high gain benefit from enhanced effective connectivity. We show that visually induced gamma-band activity in awake macaque area V4 rhythmically modulates responses to unpredictable stimulus events. This modulation exceeded a simple additive superposition of a constant response onto ongoing gamma-rhythmic firing, demonstrating the modulation of multiplicative gain...
October 5, 2016: Neuron
https://www.readbyqxmd.com/read/27660457/the-association-of-serum-gamma-glutamyl-transpeptidase-level-and-other-laboratory-parameters-with-blood-pressure-in-hypertensive-patients-under-ambulatory-blood-pressure-monitoring
#18
Adile Ortakoyluoglu, Betul Boz, Oguzhan Sıtkı Dizdar, Deniz Avcı, Ali Cetinkaya, Osman Baspınar
BACKGROUND: Hypertension is a very important cause of morbidity and mortality. Serum gamma-glutamyl transpeptidase (GGT) is a biomarker of oxidative stress and associated with increased risk of hypertension and diabetes. The aim of this study was to evaluate the association of serum GGT level, which is an early marker of inflammation and endothelial dysfunction, with the deterioration of the diurnal rhythm of the blood pressure. METHODS: A total of 171 patients with hypertension were included in this study...
2016: Therapeutics and Clinical Risk Management
https://www.readbyqxmd.com/read/27651114/circadian-dynamics-in-measures-of-cortical-excitation-and-inhibition-balance
#19
Sarah L Chellappa, Giulia Gaggioni, Julien Q M Ly, Soterios Papachilleos, Chloé Borsu, Alexandre Brzozowski, Mario Rosanova, Simone Sarasso, André Luxen, Benita Middleton, Simon N Archer, Derk-Jan Dijk, Marcello Massimini, Pierre Maquet, Christophe Phillips, Rosalyn J Moran, Gilles Vandewalle
Several neuropsychiatric and neurological disorders have recently been characterized as dysfunctions arising from a 'final common pathway' of imbalanced excitation to inhibition within cortical networks. How the regulation of a cortical E/I ratio is affected by sleep and the circadian rhythm however, remains to be established. Here we addressed this issue through the analyses of TMS-evoked responses recorded over a 29 h sleep deprivation protocol conducted in young and healthy volunteers. Spectral analyses of TMS-evoked responses in frontal cortex revealed non-linear changes in gamma band evoked oscillations, compatible with an influence of circadian timing on inhibitory interneuron activity...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27636199/gamma-synchronization-influences-map-formation-time-in-a-topological-model-of-spatial-learning
#20
Edward Basso, Mamiko Arai, Yuri Dabaghian
The mammalian hippocampus plays a crucial role in producing a cognitive map of space-an internalized representation of the animal's environment. We have previously shown that it is possible to model this map formation using a topological framework, in which information about the environment is transmitted through the temporal organization of neuronal spiking activity, particularly those occasions in which the firing of different place cells overlaps. In this paper, we discuss how gamma rhythm, one of the main components of the extracellular electrical field potential affects the efficiency of place cell map formation...
September 2016: PLoS Computational Biology
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