Read by QxMD icon Read

Gamma rhythm

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
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
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
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
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
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
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
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
Yi-Tse Hsiao, Chenguang Zheng, Laura Lee Colgin
In hippocampal area CA1, slow (~25-55 Hz) and fast (~60-100 Hz) gamma rhythms are coupled with different CA1 afferents. CA1 slow gamma is coupled to inputs from CA3, and CA1 fast gamma is coupled to inputs from the medial entorhinal cortex (Colgin et al. 2009). CA3 gives rise to highly divergent associational projections, and it is possible that reverberating activity in these connections generates slow gamma rhythms in the hippocampus. However, hippocampal gamma is maximal upstream of CA3, in the dentate gyrus (DG) region (Bragin et al...
September 14, 2016: Journal of Neurophysiology
Jessica J Barnes, Anna Christina Nobre, Mark W Woolrich, Kate Baker, Duncan E Astle
UNLABELLED: Working memory is a capacity upon which many everyday tasks depend and which constrains a child's educational progress. We show that a child's working memory can be significantly enhanced by intensive computer-based training, relative to a placebo control intervention, in terms of both standardized assessments of working memory and performance on a working memory task performed in a magnetoencephalography scanner. Neurophysiologically, we identified significantly increased cross-frequency phase amplitude coupling in children who completed training...
August 24, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Paolo Maria Rossini, Riccardo Di Iorio, Giuseppe Granata, Francesca Miraglia, Fabrizio Vecchio
In a recent study, analyzing the modulation of γ-band oscillations, Naro and colleagues demonstrated that transcranial alternating current stimulation could drive the gamma rhythms in the human EEG in cognitive healthy elderly subjects but not in mild cognitive impairment (MCI) prodromal to Alzheimer's disease (AD) and in early AD patients. Therefore, this method is proposed to intercept early in the disease course those MCI subjects who are in a pre-symptomatic stage of an already established AD. This prediction index may help the clinician to adopt a better prevention/follow-up strategy...
July 14, 2016: Journal of Alzheimer's Disease: JAD
Mina Amiri, Birgit Frauscher, Jean Gotman
The interactions between different EEG frequency bands have been widely investigated in normal and pathologic brain activity. Phase-amplitude coupling (PAC) is one of the important forms of this interaction where the amplitude of higher frequency oscillations is modulated by the phase of lower frequency activity. Here, we studied the dynamic variations of PAC of high (gamma and ripple) and low (delta, theta, alpha, and beta) frequency bands in patients with focal epilepsy in different sleep stages during the interictal period, in an attempt to see if coupling is different in more or less epileptogenic regions...
2016: Frontiers in Human Neuroscience
I I Knyazkova, N V Kuzminova, N Yu Osovskaya
The aim of this study was to investigate the influence of antihypertensive therapy with adding of gamma-amino-beta-phenylbutyric acid hydrochloride on the autonornic regulation of tcardiovascular system and the psychoemotional status in young men with hypertension. The study included 58 male with hypertension, aged 18-39 years (mean age 31.7 yearst 2.3 years), of them 28 patients (group I) administered beta-blocker and the other received a complex therapy which included beta-blocker and gamma-amino-beta-phenylbutyric acid hydrochiotide--Noofen ("OlainFarm", Latvia) 250 mg 3 times a day for 4 weeks...
October 2015: Likars'ka Sprava
Recep A Ozdemir, Jose L Contreras-Vidal, Beom-Chan Lee, William H Paloski
To date, no systematic research investigating cortical correlates of performance changes in dual tasking has been reported in the elderly population. Thus, we monitored whole-scalp cortical activations (EEG) during both single task and posture-cognition dual tasking with the main goal of understanding cortical activity modulations underlying age-related differences on posture-cognition dual tasking conditions. Postural and cognitive data analyses showed that elderly people had decreased cognitive performance even during challenging single cognitive tasks...
July 21, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
R Marecek, M Lamos, M Mikl, M Barton, J Fajkus, Rektor, M Brazdil
OBJECTIVE: The scalp EEG spectrum is a frequently used marker of neural activity. Commonly, the preprocessing of EEG utilizes constraints, e.g. dealing with a predefined subset of electrodes or a predefined frequency band of interest. Such treatment of the EEG spectrum neglects the fact that particular neural processes may be reflected in several frequency bands and/or several electrodes concurrently, and can overlook the complexity of the structure of the EEG spectrum. APPROACH: We showed that the EEG spectrum structure can be described by parallel factor analysis (PARAFAC), a method which blindly uncovers the spatial-temporal-spectral patterns of EEG...
August 2016: Journal of Neural Engineering
Adnan I Qureshi, Muhammad Shah Miran, Shijing Li, Meijing Jiang
BACKGROUND AND PURPOSE: Data from electroencephalography (EEG) in preterm infants and neonates suggest that electroencephalographic abnormalities are likely present during antepartum period or fetal stage. We describe our initial effort to record fetal EEG with emphasis on technical aspects since such technique has not been developed as a viable and reproducible method. METHODS: The fetal heads were located in two pregnant volunteers (29 years old and 26 years old) with 28 weeks of gestation by ultrasound imaging...
June 2016: Journal of Vascular and Interventional Neurology
Saori Takeuchi, Rie Murai, Hideki Shimazu, Yoshikazu Isomura, Tatsuya Mima, Toru Tsujimoto
STUDY OBJECTIVES: The sleep spindle has been implicated in thalamic sensory gating, cortical development, and memory consolidation. These multiple functions may depend on specific spatiotemporal emergence and interactions with other spindles and other forms of brain activity. Therefore, we measured sleep spindle cortical distribution, regional heterogeneity, synchronization, and phase relationships with other electroencephalographic components in freely moving primates. METHODS: Transcortical field potentials were recorded from Japanese monkeys via telemetry and were analyzed using the Hilbert-Huang transform...
2016: Sleep
Matthew Chalk, Boris Gutkin, Sophie Denève
Cortical networks exhibit 'global oscillations', in which neural spike times are entrained to an underlying oscillatory rhythm, but where individual neurons fire irregularly, on only a fraction of cycles. While the network dynamics underlying global oscillations have been well characterised, their function is debated. Here, we show that such global oscillations are a direct consequence of optimal efficient coding in spiking networks with synaptic delays and noise. To avoid firing unnecessary spikes, neurons need to share information about the network state...
2016: ELife
Joseph B Hopfinger
Voelker et al. discuss the potentially critical role of white matter changes underlying the effects of training. In regard to the specific types of neural activities and processes related to these changes, the authors focus on theta rhythms and the speed of manual response times. However, white matter changes likely affect brain oscillatory activity at multiple frequencies, and recent findings suggest structural connections may be even more important for higher frequency functional connectivity. Furthermore, activity in the gamma frequency range has been implicated in basic mechanisms of attention, and changes in these core processes could underlie improvements across multiple tasks...
June 28, 2016: Cognitive Neuroscience
Franca Tecchio, Fabrizio Vecchio, Mariacarla Ventriglia, Camillo Porcaro, Francesca Miraglia, Mariacristina Siotto, Paolo M Rossini, Mauro Rongioletti, Rosanna Squitti
BACKGROUND: Meta-analyses show that percentages of non-Cp-Cu-copper that is not bound to ceruloplasmin (also known as 'free' copper)-in serum are higher in Alzheimer's disease (AD) patients. Genetic heterogeneity in AD patients stratified on the basis of non-Cp-Cu cut-off sustains the existence of a copper AD metabolic subtype. Non-Cp-Cu abnormalities correlated with alterations of electroencephalographic rhythms (EEG). OBJECTIVE: We aimed to determine whether an EEG-derived brain cortical rhythm's heterogeneity between two AD groups stratified on the basis of a copper marker...
June 2, 2016: Current Alzheimer Research
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"