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https://www.readbyqxmd.com/read/29339471/laminar-recordings-in-frontal-cortex-suggest-distinct-layers-for-maintenance-and-control-of-working-memory
#1
André M Bastos, Roman Loonis, Simon Kornblith, Mikael Lundqvist, Earl K Miller
All of the cerebral cortex has some degree of laminar organization. These different layers are composed of neurons with distinct connectivity patterns, embryonic origins, and molecular profiles. There are little data on the laminar specificity of cognitive functions in the frontal cortex, however. We recorded neuronal spiking/local field potentials (LFPs) using laminar probes in the frontal cortex (PMd, 8A, 8B, SMA/ACC, DLPFC, and VLPFC) of monkeys performing working memory (WM) tasks. LFP power in the gamma band (50-250 Hz) was strongest in superficial layers, and LFP power in the alpha/beta band (4-22 Hz) was strongest in deep layers...
January 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29324406/a-novel-multi-class-eeg-based-sleep-stage-classification-system
#2
Pejman Memar, Farhad Faradji
Sleep stage classification is one of the most critical steps in effective diagnosis and the treatment of sleep-related disorders. Visual inspection undertaken by sleep experts is a time-consuming and burdensome task. A computer-assisted sleep stage classification system is thus essential for both sleep-related disorders diagnosis and sleep monitoring. In this paper, we propose a system to classify the wake and sleep stages with high rates of sensitivity and specificity. The EEG signals of 25 subjects with suspected sleep-disordered breathing, and the EEG signals of 20 healthy subjects from three data sets are used...
January 2018: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/29317186/perturbation-of-theta-gamma-coupling-at-the-temporal-lobe-hinders-verbal-declarative-memory
#3
Gabriel Amador de Lara, Ivan Alekseichuk, Zsolt Turi, Albert Lehr, Andrea Antal, Walter Paulus
BACKGROUND: Phase-amplitude cross-frequency coupling (PAC) is characterized by the modulation of the power of a fast brain oscillation (e.g., gamma) by the phase of a slow rhythm (e.g., theta). PAC in different sub- and neocortical regions is known to underlie effective neural communication and correlates with successful long-term memory formation. OBJECTIVE/HYPOTHESIS: The present work aims to extend earlier observational data, by probing the functional role of theta-gamma PAC in the left temporal cortex in humans during verbal long-term memory encoding...
December 25, 2017: Brain Stimulation
https://www.readbyqxmd.com/read/29313982/layer-specific-e-i-balances-during-neuronal-synchronization-in-the-visual-cortex
#4
Hillel Adesnik
Rhythmic activity can synchronize neural ensembles within and across cortical layers. While gamma band rhythmicity has been observed in all layers, the laminar sources and functional impacts of neuronal synchronization in the cortex remain incompletely understood. Here, layer-specific optogenetic stimulation demonstrates that populations of excitatory neurons in any cortical layer of the mouse's primary visual cortex are sufficient to powerfully entrain neuronal oscillations in the gamma band. Within each layer, inhibition balances excitation and keeps activity in check...
January 5, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29304108/a-four-state-markov-model-of-sleep-wakefulness-dynamics-along-light-dark-cycle-in-mice
#5
Leonel Perez-Atencio, Nicolas Garcia-Aracil, Eduardo Fernandez, Luis C Barrio, Juan A Barios
Behavioral states alternate between wakefulness (wk), rapid eye movement (rem) and non-rem (nrem) sleep at time scale of hours i.e., light and dark cycle rhythms and from several tens of minutes to seconds (i.e., brief awakenings during sleep). Using statistical analysis of bout duration, Markov chains of sleep-wk dynamics and quantitative EEG analysis, we evaluated the influence of light/dark (ld) changes on brain function along the sleep-wk cycle. Bout duration (bd) histograms and Kaplan-Meier (km) survival curves of wk showed a bimodal statistical distribution, suggesting that two types of wk do exist: brief-wk (wkb) and long-wk (wkl)...
2018: PloS One
https://www.readbyqxmd.com/read/29296618/lateral-hypothalamic-activity-indicates-hunger-and-satiety-states-in-humans
#6
Omid Talakoub, Raquel R Paiva, Matija Milosevic, Marcelo Q Hoexter, Ruth Franco, Eduardo Alho, Jessie Navarro, José F Pereira, Milos R Popovic, Cary Savage, Antonio C Lopes, Pedro Alvarenga, Durval Damiani, Manoel J Teixeira, Euripides C Miguel, Erich T Fonoff, Marcelo C Batistuzzo, Clement Hamani
Lateral hypothalamic area (LHA) local field potentials (LFPs) were recorded in a Prader-Willi patient undergoing deep brain stimulation (DBS) for obesity. During hunger, exposure to food-related cues induced an increase in beta/low-gamma activity. In contrast, recordings during satiety were marked by prominent alpha rhythms. Based on these findings, we have delivered alpha-frequency DBS prior to and during food intake. Despite reporting an early sensation of fullness, the patient continued to crave food. This suggests that the pattern of activity in LHA may indicate hunger/satiety states in humans but attest to the complexity of conducting neuromodulation studies in obesity...
December 2017: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/29277586/cortical-control-of-upright-stance-in-elderly
#7
Recep A Ozdemir, Jose L Contreras-Vidal, William H Paloski
This study examined differences between young and elderly volunteers in cortical involvement to human posture control during quiet stance with normal and altered sensory stimulation (Experiment-1), and biomechanical perturbations (Experiment-2). The primary focus of the first part was to monitor changes in cortical activity when unexpectedly altering the sensory conditions of upright stance, such as switching from stable (eyes open, fixed support surface) to less-stable (eyes closed, sway-referenced support surface) conditions...
December 22, 2017: Mechanisms of Ageing and Development
https://www.readbyqxmd.com/read/29259151/hippocampal-prefrontal-theta-gamma-coupling-during-performance-of-a-spatial-working-memory-task
#8
Makoto Tamura, Timothy J Spellman, Andrew M Rosen, Joseph A Gogos, Joshua A Gordon
Cross-frequency coupling supports the organization of brain rhythms and is present during a range of cognitive functions. However, little is known about whether and how long-range cross-frequency coupling across distant brain regions subserves working memory. Here we report that theta-slow gamma coupling between the hippocampus and medial prefrontal cortex (mPFC) is augmented in a genetic mouse model of cognitive dysfunction. This increased cross-frequency coupling is observed specifically when the mice successfully perform a spatial working memory task...
December 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/29249806/cortical-high-gamma-network-oscillations-and-connectivity-a-translational-index-for-antipsychotics-to-normalize-aberrant-neurophysiological-activity
#9
A Ahnaou, H Huysmans, T Van de Casteele, W H I M Drinkenburg
Oscillatory activity in the gamma frequency range is a critical mechanism, which integrates neural networks within and across brain structures during cognitive processes. In schizophrenia, abnormalities in high gamma oscillations are ubiquitous and most likely reflect dysfunction in neuronal networks. In conscious rats, disturbed network oscillations associated with positive symptoms and cognitive deficits were modeled in different cortical areas by the dopaminergic agonist (amphetamine) and the N-methyl-D-aspartate (NMDA) receptor antagonists (PCP and MK801)...
December 18, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/29233654/trophic-modulation-of-gamma-oscillations-the-key-role-of-processing-protease-for-neuregulin-1-and-bdnf-precursors
#10
Hideki Tamura, Sadao Shiosaka, Shota Morikawa
Gamma oscillations within the cerebral cortex and hippocampus are associated with cognitive processes, including attention, sensory perception, and memory formation; a deficit in gamma regulation is a common symptom of neurologic and psychiatric disorders. Accumulating evidence has suggested that gamma oscillations result from the synchronized activity of cell assemblies coordinated mainly by parvalbumin-positive inhibitory interneurons. The modulator molecules for parvalbumin-positive interneurons are major research targets and have the potential to control the specific oscillatory rhythm and behavior originating from neural coordination...
December 9, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/29226709/enhanced-brain-network-activity-in-complex-movement-rhythms-a-simultaneous-fmri-eeg-study
#11
Bhim Mani Adhikari, Charles M Epstein, Mukesh Dhamala
Generating movement rhythms is known to involve a network of distributed brain regions associated with motor planning, control, execution, and perception of timing for the repertoire of motor actions. What brain areas are bound in the network and how the network activity is modulated by rhythmic complexity have not been completely explored. To contribute to answering these questions, we designed a study in which nine healthy participants performed simple to complex rhythmic finger movement tasks while undergoing simultaneous functional magnetic resonance imaging and electroencephalography (fMRI-EEG) recordings of their brain activity during the tasks and rest...
December 10, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/29213107/brain-to-brain-synchrony-during-naturalistic-social-interactions
#12
Sivan Kinreich, Amir Djalovski, Lior Kraus, Yoram Louzoun, Ruth Feldman
The evolution of humans as a highly social species tuned the brain to the social world; yet the mechanisms by which humans coordinate their brain response online during social interactions remain unclear. Using hyperscanning EEG recordings, we measured brain-to-brain synchrony in 104 adults during a male-female naturalistic social interaction, comparing romantic couples and strangers. Neural synchrony was found for couples, but not for strangers, localized to temporal-parietal structures and expressed in gamma rhythms...
December 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29202390/abnormal-functional-connectivity-of-high-frequency-rhythms-in-drug-na%C3%A3-ve-schizophrenia
#13
Tetsuya Takahashi, Takashi Goto, Sou Nobukawa, Yuji Tanaka, Mitsuru Kikuchi, Masato Higashima, Yuji Wada
OBJECTIVE: The "dysconnection hypothesis" has been proposed as a core neural basis for schizophrenia. Although growing neuroimaging-based evidence suggests atypical functional connectivity in patients with schizophrenia, the results are inconsistent and the effects of antipsychotic treatment remain elusive. METHODS: We performed resting-state electroencephalography (EEG) in 21 drug-naïve patients with schizophrenia (14 patients were re-evaluated after administration of antipsychotic treatment) and 31 age-matched healthy control subjects...
November 21, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29161352/delta-rhythm-orchestrates-the-neural-activity-underlying-the-resting-state-bold-signal-via-phase-amplitude-coupling
#14
Saul Jaime, Hong Gu, Brian F Sadacca, Elliot A Stein, Jose E Cavazos, Yihong Yang, Hanbing Lu
Spontaneous ongoing neuronal activity is a prominent feature of the mammalian brain. Temporal and spatial patterns of such ongoing activity have been exploited to examine large-scale brain network organization and function. However, the neurophysiological basis of this spontaneous brain activity as detected by resting-state functional Magnetic Resonance Imaging (fMRI) remains poorly understood. To this end, multi-site local field potentials (LFP) and blood oxygenation level-dependent (BOLD) fMRI were simultaneously recorded in the rat striatum along with local pharmacological manipulation of striatal activity...
November 17, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29157416/the-temporal-dynamics-involved-in-object-representation-updating-to-predict-change
#15
Naomi du Bois, Mark A Elliott
The synchronization of cortically disparate neural assemblies at frequencies in the gamma-band range (30-70Hz) is considered to be involved in the perceptual organization of the environment. In support of this Elliott (2014) demonstrated improved detection of a target stimulus when this target was primed in a matrix that flickered at specific frequencies in the gamma-band range, each found to be separated by regular intervals which correspond with a 6.69Hz period. This can be explained in terms of the interaction of the stimulus (and stimulus-induced) rhythm with a slow endogenous theta rhythm...
2017: Progress in Brain Research
https://www.readbyqxmd.com/read/29125416/gamma-oscillations-in-the-somatosensory-thalamus-of-a-patient-with-a-phantom-limb-case-report
#16
Diellor Basha, Jonathan O Dostrovsky, Suneil K Kalia, Mojgan Hodaie, Andres M Lozano, William D Hutchison
The amputation of an extremity is commonly followed by phantom sensations that are perceived to originate from the missing limb. The mechanism underlying the generation of these sensations is still not clear although the development of abnormal oscillatory bursting in thalamic neurons may be involved. The theory of thalamocortical dysrhythmia implicates gamma oscillations in phantom pathophysiology although this rhythm has not been previously observed in the phantom limb thalamus. In this study, the authors report the novel observation of widespread 38-Hz gamma oscillatory activity in spike and local field potential recordings obtained from the ventral caudal somatosensory nucleus of the thalamus (Vc) of a phantom limb patient undergoing deep brain stimulation (DBS) surgery...
November 10, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29124106/gamma-rhythm-low-field-magnetic-stimulation-alleviates-neuropathologic-changes-and-rescues-memory-and-cognitive-impairments-in-a-mouse-model-of-alzheimer-s-disease
#17
Junli Zhen, Yanjing Qian, Xiechuan Weng, Wenting Su, Jianliang Zhang, Lihui Cai, Lin Dong, Haiting An, Ruijun Su, Jiang Wang, Yan Zheng, Xiaomin Wang
Introduction: The abnormal amyloid β (Aβ) accumulation and Aβ-related neural network dysfunction are considered central to the pathogenesis of Alzheimer's disease (AD) at the early stage. Deep-brain reachable low field magnetic stimulation (DMS), a novel noninvasive approach that was designed to intervene the network activity in brains, has been found to alleviate stress-related cognitive impairments. Methods: Amyloid precursor protein/presenilin-1 transgenic mice (5XFAD) were treated with DMS, and cognitive behavior and AD-like pathologic changes in the neurochemical and electrophysiological properties in 5XFAD mice were assessed...
November 2017: Alzheimer's & Dementia: Translational Research & Clinical Interventions
https://www.readbyqxmd.com/read/29120510/in-vitro-characterization-of-gamma-oscillations-in-the-hippocampal-formation-of-the-domestic-chick
#18
Pradeep Dheerendra, Nicholas M Lynch, Joseph Crutwell, Mark O Cunningham, Tom V Smulders
Avian and mammalian brains have evolved independently from each other for about 300 million years. During that time, the hippocampal formation (HF) has diverged in morphology and cyto-architecture, but seems to have conserved much of its function. It is therefore an open question how seemingly different neural organizations can generate the same function. A prominent feature of the mammalian hippocampus is that it generates different neural oscillations, including the gamma rhythm, which plays an important role in memory processing...
November 9, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/29118193/duration-analysis-using-matching-pursuit-algorithm-reveals-longer-bouts-of-gamma-rhythm
#19
Subhash Chandran Ks, Chandra Sekhar Seelamantula, Supratim Ray
The gamma rhythm (30 to 80 Hz), often associated with high-level cortical functions, is believed to provide a temporal reference frame for spiking activity, for which it should have a stable center frequency and linear phase for an extended duration. However, recent studies that have estimated the power and phase of gamma as a function of time suggest that gamma occurs in short bursts and lacks the temporal structure required to act as a reference frame. Here we show that the bursty appearance of gamma arises from the variability in the spectral estimator used in these studies...
November 8, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29108940/cortical-layers-rhythms-and-bold-signals
#20
REVIEW
René Scheeringa, Pascal Fries
This review investigates how laminar fMRI can complement insights into brain function derived from the study of rhythmic neuronal synchronization. Neuronal synchronization in various frequency bands plays an important role in neuronal communication between brain areas, and it does so on the backbone of layer-specific interareal anatomical projections. Feedforward projections originate predominantly in supragranular cortical layers and terminate in layer 4, and this pattern is reflected in inter-laminar and interareal directed gamma-band influences...
November 3, 2017: NeuroImage
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