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https://www.readbyqxmd.com/read/28162920/how-does-general-anaesthesia-affect-the-circadian-clock
#1
REVIEW
Raewyn C Poulsen, Guy R Warman, Jamie Sleigh, Nicola M Ludin, James F Cheeseman
: Post-operative patients experience sleep disturbances. Animal studies demonstrate that general anaesthesia (GA) can disrupt circadian rhythms and cause changes in the molecular clock, indicating that anaesthesia contributes to post-operative circadian disruption. Here we review the effect of anaesthesia on the circadian clock and its rhythms in order to summarise current findings outline commonalities between studies and propose mechanisms by which effects may be mediated. KEY POINTS: 1) GA has strong effects on the main neurotransmitter systems linked with circadian control (Gamma aminobutyric acid/N-methyl-D-aspartate (GABA/NMDA)) and may act by interfering with light-entrainment of the clock...
December 18, 2016: Sleep Medicine Reviews
https://www.readbyqxmd.com/read/28161453/rhythms-dysregulation-a-new-perspective-for-understanding-ptsd
#2
Jacques Dayan, Géraldine Rauchs, Bérengère Guillery-Girard
Post-traumatic stress disorder (PTSD) is a complex syndrome that may occur after exposure to one or more traumatic events. It associates physiological, emotional, and cognitive changes Brain and hormonal modifications contribute to some impairments in learning, memory, and emotion regulation. Some of these biological dysfunctions may be analyzed in terms of rhythms dysregulation that would be expressed through endocrine rhythmicity, sleep organization, and temporal synchrony in brain activity. In the first part of this article, we report studies on endocrine rhythmicity revealing that some rhythms abnormalities are frequently observed, although not constantly, for both cortisol and sympathetic nervous system (SNS) activity...
February 1, 2017: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/28159686/resting-state-electrophysiology-links-classic-brain-rhythms-and-large-scale-functional-systems
#3
Carl D Hacker, Abraham Z Snyder, Mrinal Pahwa, Maurizio Corbetta, Eric C Leuthardt
Resting state functional MRI (R-fMRI) studies have shown that slow (< 0.1Hz), intrinsic fluctuations of the blood oxygen level dependent (BOLD) signal are temporally correlated within hierarchically organized functional systems known as resting state networks (RSNs) (Doucet et al., 2011). Most broadly, this hierarchy exhibits a dichotomy between two opposed systems (Fox et al., 2005). One system engages with the environment and includes the visual, auditory, and sensorimotor (SMN) networks as well as the dorsal attention network (DAN), which controls spatial attention...
January 31, 2017: NeuroImage
https://www.readbyqxmd.com/read/28154537/odor-induced-neuronal-rhythms-in-the-olfactory-bulb-are-profoundly-modified-in-ob-ob-obese-mice
#4
Yan Chelminski, Christophe Magnan, Serge H Luquet, Amandine Everard, Nicolas Meunier, Hirac Gurden, Claire Martin
Leptin, the product of the Ob(Lep) gene, is a peptide hormone that plays a major role in maintaining the balance between food intake and energy expenditure. In the brain, leptin receptors are expressed by hypothalamic cells but also in the olfactory bulb, the first central structure coding for odors, suggesting a precise function of this hormone in odor-evoked activities. Although olfaction plays a key role in feeding behavior, the ability of the olfactory bulb to integrate the energy-related signal leptin is still missing...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28109667/aberrant-alpha-and-gamma-oscillations-ex-vivo-after-single-application-of-the-nmda-receptor-antagonist-mk-801
#5
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
#6
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/28072877/motor-cortex-theta-and-gamma-architecture-in-young-adult-appsweps1de9-alzheimer-mice
#7
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
#8
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-oscillations-in-a-full-scale-model-of-the-rodent-ca1-circuit
#9
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
#10
MULTICENTER STUDY
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...
February 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/27929004/gamma-frequency-entrainment-attenuates-amyloid-load-and-modifies-microglia
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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