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high-frequency oscillations consciousness

Yi-Hsien Lin, Yia-Ping Liu, Yu-Chieh Lin, Po-Lei Lee, Che-Se Tung
Rapid immersion of a rat's limbs into 4 °C water, a model of cold stress, can elicit hemodynamic perturbations (CEHP). We previously reported that CEHP is highly relevant to sympathetic activation and nitric oxide production. This study identifies the role of nitric oxide in CEHP. Conscious rats were pretreated with the nitric oxide synthase inhibitor L-NAME (N(G)-nitro-l-arginine methyl ester) alone or following the removal of sympathetic influences using hexamethonium or guanethidine. Rats were then subjected to a 10 min cold-stress trial...
July 2017: Canadian Journal of Physiology and Pharmacology
Anne Kösem, Anahita Basirat, Leila Azizi, Virginie van Wassenhove
During speech listening, the brain parses a continuous acoustic stream of information into computational units (e.g., syllables or words) necessary for speech comprehension. Recent neuroscientific hypotheses have proposed that neural oscillations contribute to speech parsing, but whether they do so on the basis of acoustic cues (bottom-up acoustic parsing) or as a function of available linguistic representations (top-down linguistic parsing) is unknown. In this magnetoencephalography study, we contrasted acoustic and linguistic parsing using bistable speech sequences...
December 1, 2016: Journal of Neurophysiology
Christian Endisch, Gunnar Waterstraat, Christian Storm, Christoph J Ploner, Gabriel Curio, Christoph Leithner
OBJECTIVE: Following cardiac arrest (CA), hypoxic encephalopathy (HE) frequently occurs and hence reliable neuroprognostication is crucial to decide on the extent of intensive care. Several investigations predict severe HE leading to persistent unresponsive wakefulness or death, with high specificity. Only few studies attempted to predict absence of severe HE. Cortical somatosensory evoked high-frequency (600Hz) oscillation (HFO) bursts indicate the presence of highly synchronized spiking activity in the primary somatosensory cortex...
July 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Miles Berger, Paul S García
No abstract text is available yet for this article.
June 2016: Anesthesia and Analgesia
Usman Farooq, Jigna Rajesh Kumar, Ramamoorthy Rajkumar, Gavin S Dawe
Locomotion is essential for goal-oriented behavior. Theta frequency oscillations in the hippocampus have been associated with behavioral activation and initiation of movement. Recently, the nucleus incertus, a brainstem nucleus with widespread cortical and subcortical projections, has been reported to modulate the septo-hippocampal axis triggering theta activity in the hippocampus. This suggests that activation of the nucleus incertus would induce movement. In this study, we investigated the effects of electrical microstimulation of the nucleus incertus on locomotion in conscious rats...
June 1, 2016: Physiology & Behavior
Yongzhi Huang, Jianghong He, Alexander L Green, Tipu Z Aziz, John F Stein, Shouyan Wang
A functioning thalamus is essential for treatment of patients with disorders of consciousness (DOC) using deep brain stimulation (DBS). This work aims to identify the potential biomarkers related to consciousness from the thalamic deep brain local field potentials (LFPs) in DOC patients. The frequency features of central thalamic LFPs were characterized with spectral analysis. The features were further compared to those of LFPs from the ventroposterior lateral nucleus of the thalamus (VPL) in patients with pain...
August 2015: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Randolph F Helfrich, Christoph S Herrmann, Andreas K Engel, Till R Schneider
Cross-frequency coupling (CFC) has been suggested to constitute a highly flexible mechanism for cortical information gating and processing, giving rise to conscious perception and various higher cognitive functions in humans. In particular, it might provide an elegant tool for information integration across several spatiotemporal scales within nested or coupled neuronal networks. However, it is currently unknown whether low-frequency (theta/alpha) or high-frequency gamma oscillations orchestrate cross-frequency interactions, raising the question of who is master and who is slave...
October 15, 2016: NeuroImage
Francisco J Flores, ShiNung Ching, Katharine Hartnack, Amanda B Fath, Patrick L Purdon, Matthew A Wilson, Emery N Brown
OBJECTIVE: Ketamine is a widely used drug with clinical and research applications, and also known to be used as a recreational drug. Ketamine produces conspicuous changes in the electrocorticographic (ECoG) signals observed both in humans and rodents. In rodents, the intracranial ECoG displays a high-frequency oscillation (HFO) which power is modulated nonlinearly by ketamine dose. Despite the widespread use of ketamine there is no model description of the relationship between the pharmacokinetic-pharmacodynamics (PK-PDs) of ketamine and the observed HFO power...
October 2015: Journal of Neural Engineering
Yia-Ping Liu, Yi-Hsien Lin, Yu-Chun Chen, Po-Lei Lee, Che-Se Tung
AIMS: Oscillations in arterial pressure and heart period in response to cold stress are poorly understood. We used a telemetric device with spectral and cross-spectral analyses to assess variabilities in the heart rate (HRV) and blood pressure (BPV) of conscious rats receiving a cooling stimulus (CS) (rapid immersion of palms and soles into 4°C water) at ambient thermoneutral conditions (TC), in a cold room (CC), and when under pentobarbital anesthesia (UA). MAIN METHODS: Power spectra of very low, low, and high frequencies (VLF: 0...
September 1, 2015: Life Sciences
Jonathan Levy, Juan R Vidal, Pascal Fries, Jean-François Démonet, Abraham Goldstein
The emergence of conscious visual perception is assumed to ignite late (∼250 ms) gamma-band oscillations shortly after an initial (∼100 ms) forward sweep of neural sensory (nonconscious) information. However, this neural evidence is not utterly congruent with rich behavioral data which rather point to piecemeal (i.e., graded) perceptual processing. To address the unexplored neural mechanisms of piecemeal ignition of conscious perception, hierarchical script sensitivity of the putative visual word form area (VWFA) was exploited to signal null (i...
July 2016: Cerebral Cortex
Seth T Fairfax, Joseph R H Mauban, Scarlett Hao, Mark A Rizzo, Jin Zhang, W Gil Wier
UNLABELLED: Two-photon fluorescence microscopy and conscious, restrained optical biosensor mice were used to study smooth muscle Ca(2+) signaling in ear arterioles. Conscious mice were used in order to preserve normal mean arterial blood pressure (MAP) and sympathetic nerve activity (SNA). ExMLCK mice, which express a genetically-encoded smooth muscle-specific FRET-based Ca(2+) indicator, were equipped with blood pressure telemetry and immobilized for imaging. MAP was 101 ± 4 mmHg in conscious restrained mice, similar to the freely mobile state (107 ± 3 mmHg)...
2014: Frontiers in Physiology
Stavros I Dimitriadis, Yu Sun, Kenneth Kwok, Nikolaos A Laskaris, Nitish Thakor, Anastasios Bezerianos
The decoding of conscious experience, based on non-invasive measurements, has become feasible by tailoring machine learning techniques to analyse neuroimaging data. Recently, functional connectivity graphs (FCGs) have entered into the picture. In the related decoding scheme, FCGs are treated as unstructured data and, hence, their inherent format is overlooked. To alleviate this, tensor subspace analysis (TSA) is incorporated for the parsimonious representation of connectivity data. In addition to the particular methodological innovation, this work also makes a contribution at a conceptual level by encoding in FCGs cross-frequency coupling apart from the conventional frequency-specific interactions...
April 2015: Annals of Biomedical Engineering
Rowan Baker, Thomas C Gent, Qianzi Yang, Susan Parker, Alexei L Vyssotski, William Wisden, Stephen G Brickley, Nicholas P Franks
How general anesthetics cause loss of consciousness is unknown. Some evidence points toward effects on the neocortex causing "top-down" inhibition, whereas other findings suggest that these drugs act via subcortical mechanisms, possibly selectively stimulating networks promoting natural sleep. To determine whether some neuronal circuits are affected before others, we used Morlet wavelet analysis to obtain high temporal resolution in the time-varying power spectra of local field potentials recorded simultaneously in discrete brain regions at natural sleep onset and during anesthetic-induced loss of righting reflex in rats...
October 1, 2014: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
E Angelopoulos
In the last decade there is extensive evidence to suggest that cognitive functions depending on coordination of distributed neuronal responses are associated with synchronized oscillatory activity in various frequency ranges suggesting a functional mechanism of neural oscillations in cortical networks. In addition to their role in normal brain functioning, there is increasing evidence that altered oscillatory activity may be associated with certain neuropsychiatric disorders, such as schizophrenia. Consequently, disturbances in neural synchronization may represent the functional relationship of disordered connectivity of cortical networks underlying the characteristic fragmentation of mind and behavior in schizophrenia...
April 2014: Psychiatrikē, Psychiatriki
Leandro M Alonso, Alex Proekt, Theodore H Schwartz, Kane O Pryor, Guillermo A Cecchi, Marcelo O Magnasco
In this work we analyze electro-corticography (ECoG) recordings in human subjects during induction of anesthesia with propofol. We hypothesize that the decrease in responsiveness that defines the anesthetized state is concomitant with the stabilization of neuronal dynamics. To test this hypothesis, we performed a moving vector autoregressive analysis and quantified stability of neuronal dynamics using eigenmode decomposition of the autoregressive matrices, independently fitted to short sliding temporal windows...
2014: Frontiers in Neural Circuits
Luca Bonfiglio, Andrea Piarulli, Umberto Olcese, Paolo Andre, Pieranna Arrighi, Antonio Frisoli, Bruno Rossi, Massimo Bergamasco, Maria Chiara Carboncini
Recently, the cortical source of blink-related delta oscillations (delta BROs) in resting healthy subjects has been localized in the posterior cingulate cortex/precuneus (PCC/PCu), one of the main core-hubs of the default-mode network. This has been interpreted as the electrophysiological signature of the automatic monitoring of the surrounding environment while subjects are immersed in self-reflecting mental activities. Although delta BROs were directly correlated to the degree of consciousness impairment in patients with disorders of consciousness, they failed to differentiate vegetative state/unresponsive wakefulness syndrome (VS/UWS) from minimally conscious state (MCS)...
2014: PloS One
Romain Quentin, Lorena Chanes, Marine Vernet, Antoni Valero-Cabré
May white matter connectivity influence rhythmic brain activity underlying visual cognition? We here employed diffusion imaging to reconstruct the fronto-parietal white matter pathways in a group of healthy participants who displayed frequency-specific ameliorations of visual sensitivity during the entrainment of high-beta oscillatory activity by rhythmic transcranial magnetic stimulation over their right frontal eye field. Our analyses reveal a strong tract-specific association between the volume of the first branch of the superior longitudinal fasciculus and improvements of conscious visual detection driven by frontal beta oscillation patterns...
August 2015: Cerebral Cortex
Eran A Mukamel, Elvira Pirondini, Behtash Babadi, Kin Foon Kevin Wong, Eric T Pierce, P Grace Harrell, John L Walsh, Andres F Salazar-Gomez, Sydney S Cash, Emad N Eskandar, Veronica S Weiner, Emery N Brown, Patrick L Purdon
Rhythmic oscillations shape cortical dynamics during active behavior, sleep, and general anesthesia. Cross-frequency phase-amplitude coupling is a prominent feature of cortical oscillations, but its role in organizing conscious and unconscious brain states is poorly understood. Using high-density EEG and intracranial electrocorticography during gradual induction of propofol general anesthesia in humans, we discovered a rapid drug-induced transition between distinct states with opposite phase-amplitude coupling and different cortical source distributions...
January 15, 2014: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Gerick M H Lee, Sara Fattinger, Anne-Laure Mouthon, Quentin Noirhomme, Reto Huber
The use of information-based measures to assess changes in conscious state is an increasingly popular topic. Though recent results have seemed to justify the merits of such methods, little has been done to investigate the applicability of such measures to children. For our work, we used the approximate entropy (ApEn), a measure previously shown to correlate with changes in conscious state when applied to the electroencephalogram (EEG), and sought to confirm whether previously reported trends in adult ApEn values across wake and sleep were present in children...
2013: Frontiers in Neuroinformatics
Paolo Manganotti, Emanuela Formaggio, Alessandra Del Felice, Silvia F Storti, Alessandro Zamboni, Alessandra Bertoldo, Antonio Fiaschi, Gianna M Toffolo
The occurrence of dynamic changes in spontaneous electroencephalogram (EEG) rhythms in the awake state or sleep is highly variable. These rhythms can be externally modulated during transcranial magnetic stimulation (TMS) with a perturbation method to trigger oscillatory brain activity. EEG-TMS co-registration was performed during standard wake, during wake after sleep deprivation and in sleep in six healthy subjects. Dynamic changes in the regional neural oscillatory activity of the cortical areas were characterized using time-frequency analysis based on the wavelet method, and the modulation of induced oscillations were related to different vigilance states...
2013: Frontiers in Human Neuroscience
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