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https://www.readbyqxmd.com/read/28926001/ketamine-differential-neurophysiological-dynamics-in-functional-networks-in-the-rat-brain
#1
A Ahnaou, H Huysmans, R Biermans, N V Manyakov, W H I M Drinkenburg
Recently, the N-methyl-d-aspartate-receptor (NMDAR) antagonist ketamine has emerged as a fast-onset mechanism to achieve antidepressant activity, whereas its psychomimetic, dissociative and amnestic effects have been well documented to pharmacologically model schizophrenia features in rodents. Sleep-wake architecture, neuronal oscillations and network connectivity are key mechanisms supporting brain plasticity and cognition, which are disrupted in mood disorders such as depression and schizophrenia. In rats, we investigated the dynamic effects of acute and chronic subcutaneous administration of ketamine (2...
September 19, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28922535/power-and-coherence-of-cortical-high-frequency-oscillations-during-wakefulness-and-sleep
#2
Matías Cavelli, Daniel Rojas-Líbano, Natalia Schwarzkopf, Santiago Castro-Zaballa, Joaquín Gonzalez, Alejandra Mondino, Noelia Santana, Luciana Benedetto, Atilio Falconi, Pablo Torterolo
Recently, a novel type of fast cortical oscillatory activity that occurs between 110 and 160 Hz (high-frequency oscillations (HFO)) was described. HFO are modulated by the theta rhythm in hippocampus and neocortex during active wakefulness and REM sleep. Since theta-HFO coupling increases during REM, a role for HFO in memory consolidation has been proposed. However, global properties like the cortex-wide topographic distribution, and the cortico-cortical coherence remain unknown. In the present study, we recorded the electroencephalogram during sleep and wakefulness in the rat, and analyzed the spatial extent of the HFO band power and coherence...
September 18, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28890054/home-cage-odors-spatial-cues-elicit-theta-phase-gamma-amplitude-coupling-between-olfactory-bulb-and-dorsal-hippocampus
#3
Roberta Ribas Pena, Daniel de Castro Medeiros, Leonardo de Oliveira Guarnieri, Julio Boriollo Guerra, Vinícius Rezende Carvalho, Eduardo Mazoni Andrade Marçal Mendes, Grace Schenatto Pereira, Márcio Flávio Dutra Moraes
The brain oscillations may play a critical role in synchronizing neuronal assemblies in order to establish appropriate sensory-motor integration. In fact, studies have demonstrated phase-amplitude coupling of distinct oscillatory rhythms during cognitive processes. Here we investigated whether olfacto-hippocampal coupling occurs when mice are detecting familiar odors located in a spatially restricted area of a new context. The spatial olfactory task (SOT) was designed to expose mice to a new environment in which only one quadrant (target) contains odors provided by its own home-cage bedding...
September 7, 2017: Neuroscience
https://www.readbyqxmd.com/read/28890051/systemic-administration-of-two-different-anxiolytic-drugs-decreases-local-field-potential-theta-frequency-in-the-medial-entorhinal-cortex-without-affecting-grid-cell-firing-fields
#4
Caitlin K Monaghan, G William Chapman, Michael E Hasselmo
Neurons coding spatial location (grid cells) are found in medial entorhinal cortex (MEC) and demonstrate increasing size of firing fields and spacing between fields (grid scale) along the dorsoventral axis. This change in grid scale correlates with differences in theta frequency, a 6-10Hz rhythm in the local field potential (LFP) and rhythmic firing of cells. A relationship between theta frequency and grid scale can be found when examining grid cells recorded in different locations along the dorsoventral axis of MEC...
September 8, 2017: Neuroscience
https://www.readbyqxmd.com/read/28887385/prior-learning-of-relevant-non-aversive-information-is-a-boundary-condition-for-avoidance-memory-reconsolidation-in-the-rat-hippocampus
#5
Andressa Radiske, Maria Carolina Gonzalez, Sergio Conde-Ocaziones, Anatildes Feitosa, Cristiano A Köhler, Lia R Bevilaqua, Martín Cammarota
Reactivated memories can be modified during reconsolidation, making this process a potential therapeutic target for post-traumatic stress disorder (PTSD), a mental illness characterized by the recurring avoidance of situations that evoke trauma-related fears. However, avoidance memory reconsolidation depends on a set of still loosely defined boundary conditions, limiting the translational value of basic research. In particular, the involvement of the hippocampus in fear-motivated avoidance memory reconsolidation remains controversial...
September 8, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28887226/reconciling-the-different-faces-of-hippocampal-theta-the-role-of-theta-oscillations-in-cognitive-emotional-and-innate-behaviors
#6
REVIEW
Tatiana Korotkova, Alexey Ponomarenko, Caitlin K Monaghan, Steven L Poulter, Francesca Cacucci, Tom Wills, Michael E Hasselmo, Colin Lever
The theta oscillation (5-10Hz) is a prominent behavior-specific brain rhythm. This review summarizes studies showing the multifaceted role of theta rhythm in cognitive functions, including spatial coding, time coding and memory, exploratory locomotion and anxiety-related behaviors. We describe how activity of hippocampal theta rhythm generators - medial septum, nucleus incertus and entorhinal cortex, links theta with specific behaviors. We review evidence for functions of the theta-rhythmic signaling to subcortical targets, including lateral septum...
September 5, 2017: Neuroscience and Biobehavioral Reviews
https://www.readbyqxmd.com/read/28867480/vagus-nerve-stimulation-produces-a-hippocampal-formation-theta-rhythm-in-anesthetized-rats
#7
Adam Broncel, Renata Bocian, Paulina Kłos-Wojtczak, Jan Konopacki
Vagus nerve stimulation (VNS) has been used for years to treat patients with drug-resistant epilepsy. In the present study, the effect of different stimulation protocols of VNS on the hippocampal formation (HPC) type II theta field potentials were evaluated in anesthetized rats. The following theta parameters were analysed: power, frequency and duration of theta epochs. We documented for the first time the presence of HPC type II theta in response to the application of VNS. A VNS-induced theta rhythm appeared in different experimental protocols and, depending on the current intensity, could occur directly during VNS (brief effect) or after vagal stimulation (delayed effect), using lower intensity stimuli...
August 31, 2017: Brain Research
https://www.readbyqxmd.com/read/28844761/the-effect-of-pharmacological-inactivation-of-the-mammillary-body-and-anterior-thalamic-nuclei-on-hippocampal-theta-rhythm-in-urethane-anesthetized-rats
#8
Witold Żakowski, Piotr Zawistowski, Łukasz Braszka, Edyta Jurkowlaniec
The mammillary body (MB) and the anterior thalamic nuclei (ATN) are closely related structures, which take part in learning and memory processes. However, the exact role of these structures has remained unclear. In both structures neurons firing according to hippocampal theta rhythm have been found, mainly in the medial mammillary nucleus (MM) and anteroventral thalamic nucleus (AV). These neurons are driven by descending projections from the hippocampal formation and are thought to convey theta rhythm back to the hippocampus (HP)...
August 24, 2017: Neuroscience
https://www.readbyqxmd.com/read/28833629/olfactory-bulb-drives-respiration-coupled-beta-oscillations-in-the-rat-hippocampus
#9
André Lv Lockmann, Diego A Laplagne, Adriano Bl Tort
The synchronization of neuronal oscillations has been suggested as a mechanism to coordinate information flow between distant brain regions. In particular, the olfactory bulb (OB) and the hippocampus (HPC) have been shown to exhibit oscillations in the beta frequency range (10-20 Hz) that are likely to support communication between these structures. Here we further characterize features of beta oscillations in OB and HPC of rats anesthetized with urethane. We find that beta oscillations simultaneously appear in HPC and OB and phase-lock across structures...
August 22, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28813670/nkx2-1-is-required-in-the-embryonic-septum-for-cholinergic-system-development-learning-and-memory
#10
Lorenza Magno, Caswell Barry, Christoph Schmidt-Hieber, Polyvios Theodotou, Michael Häusser, Nicoletta Kessaris
The transcription factor NKX2-1 is best known for its role in the specification of subsets of cortical, striatal, and pallidal neurons. We demonstrate through genetic fate mapping and intersectional focal septal deletion that NKX2-1 is selectively required in the embryonic septal neuroepithelium for the development of cholinergic septohippocampal projection neurons and large subsets of basal forebrain cholinergic neurons. In the absence of NKX2-1, these neurons fail to develop, causing alterations in hippocampal theta rhythms and severe deficiencies in learning and memory...
August 15, 2017: Cell Reports
https://www.readbyqxmd.com/read/28811195/epileptic-interictal-discharges-are-more-frequent-during-nrem-slow-wave-downstates
#11
Péter Przemyslaw Ujma, Péter Halász, Anna Kelemen, Dániel Fabó, Loránd Erőss
Epileptiform activity in various but not all epilepsy and recording types and cerebral areas is more frequent in NREM sleep, and especially during sleep periods with high-amplitude EEG slow waves. Slow waves synchronize high-frequency oscillations: physiological activity from the theta through the gamma band usually appears during scalp-positive upstates while epileptiform activity occurs at transitory phases and the scalp-negative downstate. It has been proposed that interictal discharges (IIDs) are facilitated by the high degree of neuronal firing synchrony during slow wave transitory and downstates...
August 12, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28809843/tuning-in-the-hippocampal-theta-band-in-vitro-methodologies-for-recording-from-the-isolated-rodent-septohippocampal-circuit
#12
Frédéric Manseau, Sylvain Williams
This protocol outlines the procedures for preparing and recording from the isolated whole hippocampus, of WT and transgenic mice, along with recent improvements in methodologies and applications for the study of theta oscillations. A simple characterization of the isolated hippocampal preparation is presented whereby the relationship between internal hippocampal theta oscillators is examined together with the activity of pyramidal cells, and GABAergic interneurons, of the cornu ammonis-1 (CA1) and subiculum (SUB) areas...
August 2, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28800613/ongoing-slow-oscillatory-phase-modulates-speech-intelligibility-in-cooperation-with-motor-cortical-activity
#13
Takayuki Onojima, Keiichi Kitajo, Hiroaki Mizuhara
Neural oscillation is attracting attention as an underlying mechanism for speech recognition. Speech intelligibility is enhanced by the synchronization of speech rhythms and slow neural oscillation, which is typically observed as human scalp electroencephalography (EEG). In addition to the effect of neural oscillation, it has been proposed that speech recognition is enhanced by the identification of a speaker's motor signals, which are used for speech production. To verify the relationship between the effect of neural oscillation and motor cortical activity, we measured scalp EEG, and simultaneous EEG and functional magnetic resonance imaging (fMRI) during a speech recognition task in which participants were required to recognize spoken words embedded in noise sound...
2017: PloS One
https://www.readbyqxmd.com/read/28798683/enhanced-gamma-activity-and-cross-frequency-interaction-of-resting-state-electroencephalographic-oscillations-in-patients-with-alzheimer-s-disease
#14
Jing Wang, Yuxing Fang, Xiao Wang, Huichao Yang, Xin Yu, Huali Wang
Cognitive impairment, functional decline and behavioral symptoms that characterize Alzheimer's disease (AD) are associated with perturbations of the neuronal network. The typical electroencephalographic (EEG) features in AD patients are increased delta or theta rhythm and decreased alpha or beta rhythm activities. However, considering the role of cross-frequency couplings in cognition, the alternation of cross-frequency couplings in AD patients is still obscure. This study aims to explore the interaction dynamics between different EEG oscillations in AD patients...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28794419/traveling-theta-waves-and-the-hippocampal-phase-code
#15
Christian Leibold, Mauro M Monsalve-Mercado
Hippocampal place fields form a neuronal map of the spatial environment. In addition, the distance between two place field centers is proportional to the firing phase difference of two place cells with respect to the local theta rhythm. This consistency between spatial distance and theta phase is generally assumed to result from hippocampal phase precession: The firing phase of a place cell decreases with distance traveled in the place field. The rate of phase precession depends on place field width such that the phase range covered in a traversal of a place field is independent of field width...
August 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28791333/combining-theory-model-and-experiment-to-explain-how-intrinsic-theta-rhythms-are-generated-in-an-in-vitro-whole-hippocampus-preparation-without-oscillatory-inputs
#16
Katie A Ferguson, Alexandra P Chatzikalymniou, Frances K Skinner
Scientists have observed local field potential theta rhythms (3-12 Hz) in the hippocampus for decades, but understanding the mechanisms underlying their generation is complicated by their diversity in pharmacological and frequency profiles. In addition, interactions with other brain structures and oscillatory drives to the hippocampus during distinct brain states has made it difficult to identify hippocampus-specific properties directly involved in theta generation. To overcome this, we develop cellular-based network models using a whole hippocampus in vitro preparation that spontaneously generates theta rhythms...
July 2017: ENeuro
https://www.readbyqxmd.com/read/28782904/role-of-olfactory-reactions-nociception-and-immunoendocrine-shifts-in-addictive-disorders
#17
Elena Masterova, Tatiana Nevidimova, Dariya Savochkina, Valentina Nikitina, Olga Lobacheva, Tamara Vetlugina, Nikolay Bokhan
BACKGROUND AND OBJECTIVES: Addictive pathology is associated with nervous, immune, and endocrine shifts. Meanwhile, the nature of intersystemic relationship lying beneath addictive disorders remains unclear. The purpose of the study was to identify neuroimmunoendocrine markers of addictive disorders in male subjects defining the nature of their interaction. METHODS: The study enrolled 69 subjects aged 18-43 years: 59 males and 10 females divided into those with addictive disorders (n = 39) and conditionally healthy subjects (n = 30)...
August 7, 2017: American Journal on Addictions
https://www.readbyqxmd.com/read/28768157/neurofeedback-of-smr-and-beta1-frequencies-an-investigation-of-learning-indices-and-frequency-specific-effects
#18
Miguel G Pimenta, Chris van Run, Jan W de Fockert, John H Gruzelier
Despite evidence that Sensorimotor Rhythm (SMR) and beta1 neurofeedback have distinct cognitive enhancement effects, it remains unclear whether their amplitudes can be independently enhanced. Furthermore, demands for top-down attention control, postural restraint and maintenance of cognitive set processes, all requiring low-beta frequencies, might masquerade as learning and confound interpretation. The feasibility of selectively enhancing SMR and beta1 amplitudes was investigated with the addition of a random frequency control condition that also requires the potentially confounding cognitive processes...
July 30, 2017: Neuroscience
https://www.readbyqxmd.com/read/28744955/cortical-connectivity-modulation-during-sleep-onset-a-study-via-graph-theory-on-eeg-data
#19
Fabrizio Vecchio, Francesca Miraglia, Maurizio Gorgoni, Michele Ferrara, Francesco Iberite, Placido Bramanti, Luigi De Gennaro, Paolo Maria Rossini
Sleep onset is characterized by a specific and orchestrated pattern of frequency and topographical EEG changes. Conventional power analyses of electroencephalographic (EEG) and computational assessments of network dynamics have described an earlier synchronization of the centrofrontal areas rhythms and a spread of synchronizing signals from associative prefrontal to posterior areas. Here, we assess how "small world" characteristics of the brain networks, as reflected in the EEG rhythms, are modified in the wakefulness-sleep transition comparing the pre- and post-sleep onset epochs...
July 26, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28742498/subthalamic-nucleus-gamma-activity-increases-not-only-during-movement-but-also-during-movement-inhibition
#20
Petra Fischer, Alek Pogosyan, Damian M Herz, Binith Cheeran, Alexander L Green, James Fitzgerald, Tipu Z Aziz, Jonathan Hyam, Simon Little, Thomas Foltynie, Patricia Limousin, Ludvic Zrinzo, Peter Brown, Huiling Tan
Gamma activity in the subthalamic nucleus (STN) is widely viewed as a pro-kinetic rhythm. Here we test the hypothesis that rather than being specifically linked to movement execution, gamma activity reflects dynamic processing in this nucleus. We investigated the role of gamma during fast stopping and recorded scalp electroencephalogram and local field potentials from deep brain stimulation electrodes in 9 Parkinson's disease patients. Patients interrupted finger tapping (paced by a metronome) in response to a stop-signal sound, which was timed such that successful stopping would occur only in ~50% of all trials...
July 25, 2017: ELife
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