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Yonglu Tian, Chaojuan Yang, Yaxuan Cui, Feng Su, Yongjie Wang, Yangzhen Wang, Peijiang Yuan, Shujiang Shang, Hao Li, Jizong Zhao, Desheng Zhu, Shiming Tang, Peng Cao, Yunbo Liu, Xunli Wang, Liecheng Wang, Wenbo Zeng, Haifei Jiang, Fei Zhao, Minhua Luo, Wei Xiong, Zilong Qiu, Xiang-Yao Li, Chen Zhang
Short-term memory (STM) is crucial for animals to hold information for a small period of time. Persistent or recurrent neural activity, together with neural oscillations, is known to encode the STM at the cellular level. However, the coding mechanisms at the microcircuitry level remain a mystery. Here, we performed two-photon imaging on behaving mice to monitor the activity of neuronal microcircuitry. We discovered a neuronal subpopulation in the medial prefrontal cortex (mPFC) that exhibited emergent properties in a context-dependent manner underlying a STM-like behavior paradigm...
February 13, 2018: Cell Reports
Kamau Pierre, Rohit T Rao, Clara Hartmanshenn, Ioannis P Androulakis
Synchronization of biological functions to environmental signals enables organisms to anticipate and appropriately respond to daily external fluctuations and is critical to the maintenance of homeostasis. Misalignment of circadian rhythms with environmental cues is associated with adverse health outcomes. Cortisol, the downstream effector of hypothalamic-pituitary-adrenal (HPA) activity, facilitates synchronization of peripheral biological processes to the environment. Cortisol levels exhibit substantial seasonal rhythmicity, with peak levels occurring during the short-photoperiod winter months and reduced levels occurring in the long-photoperiod summer season...
February 12, 2018: Endocrinology
Allan Bereczki, Márcio André Prieto Aparício Lopez, Niklaus Ursus Wetter
A simple, reliable, linearly polarized laser source with very high beam quality is demonstrated using standard diode-side-pumped Nd:YAG modules. The laser produced 30 W of output power with beam quality factor M2<1.15 over the entire range of input powers and beam quality of 1.02 at the laser operation point. This is, to our knowledge, the highest beam quality for a dynamically stable high-power laser that uses an optically isotropic crystal. The laser was used as a pump source for an optical parametric oscillator based on a periodically poled lithium niobate, producing wavelength in the 1...
February 15, 2018: Optics Letters
Georgii Shamuilov, Alan Mak, Peter Salén, Vitaliy Goryashko
This Letter builds upon a recent concept [Phys. Rev. Lett.113, 104801 (2014)PRLTAO0031-900710.1103/PhysRevLett.113.104801] for producing ultrashort optical pulses through the coherent radiation of electrons in an undulator. Each pulse contains only a single oscillation cycle, and has a controlled waveform (and hence a stable carrier-envelope phase). While the concept had been demonstrated numerically, this Letter provides an analytical model for the radiation mechanism, thereby revealing three key observations: (i) the correlation between the waveforms of the optical and undulator fields; (ii) the free-space dispersion of transversely confined light; and (iii) the dependence of the optical pulse shape on the undulator field strength...
February 15, 2018: Optics Letters
Virginie Sabado, Emi Nagoshi
The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. The molecular clock within each pacemaker neuron generates circadian rhythms in gene expression, which underlie the rhythmic neuronal functions essential to the operation of the circuit. Investigation of the properties of the individual molecular oscillators in different subclasses of pacemaker neurons and their interaction with neuronal signaling yields a better understanding of the circadian pacemaker circuit...
January 19, 2018: Journal of Visualized Experiments: JoVE
Liangli Cao, Yuren Jiang, Zhencheng Chen
In the present research an attempt was made to develop and optimize rapamycin (Rapa) loaded hollow magnetic Fe3O4/graphene oxide (Fe3O4/GO) nanocomposites using solvent evaporation technique and response surface methodology (RSM). A Box-Behnken design (BBD) with a three-level, three-factor was used to determine preparation parameters that would achieve the highest encapsulation efficiency (EE) and drug loading capacity (DLC). At optimum conditions such as mass ratio of Rapa to Fe3O4/GO (Rapa: Fe3O4/GO) 0.45, oscillation rate 144...
May 1, 2018: Journal of Nanoscience and Nanotechnology
Qi Luo, Xueshuang Deng, Wenhan Chen, Hai Guo, Wei Ou-Yang, Xiaohong Chen, Sumei Huang
We report a simple method for the fabrication of a three-layered plasmonic structure of silicon substrate-Au nanospheres-upconversion particles (UCNPs) that displays up to 101-fold fluorescence enhancement. Monodispersed pure hexagonal-phase NaYF4:Yb,Er core and NaYF4:Yb,Er@NaYF4 core@shell nanocrystals were prepared by a solvothermal method. Two dimensional (2D) assembled Au spheres were prepared on a Si substrate, and then, 2D arrays of UCNPs were deposited on the grown 2D monolayered Au spheres by a self-organizing process...
July 1, 2018: Journal of Nanoscience and Nanotechnology
Michael Everett Rule, Carlos E Vargas-Irwin, John P Donoghue, Wilson Truccolo
Previous studies on the origin and properties of spatial patterns in motor cortex beta local field potential (β-LFP) oscillations have focused on planar traveling waves. However, it is unclear (a) whether β-LFP waves are limited to plane waves, or even (b) whether they are propagating waves of excito-excitatory activity, i.e. primarily traveling waves in excitable media; they could reflect, instead, reorganization in the relative phases of transient oscillations at different spatial sites. We addressed these two problems in β-LFPs recorded via microelectrode arrays implanted in three adjacent motor-cortex areas of non-human primates during steady-state movement preparation...
February 14, 2018: Journal of Neurophysiology
Valentina La Scaleia, Y Ivanenko, A Fabiano, F Sylos-Labini, G Cappellini, S Picone, P Paolillo, A Di Paolo, F Lacquaniti
The accomplishment of mature locomotor movements relies upon the integrated coordination of the lower and upper limbs and the trunk. Human adults normally swing their arms and a quadrupedal limb coordination persists during bipedal walking despite a strong corticospinal control of the upper extremities that allows to uncouple this connection during voluntary activities. Here we investigated arm-leg coordination during stepping responses on a surface in human neonates. In eight neonates, we found the overt presence of alternating arm-leg oscillations, the arms moving up and down in alternation with ipsilateral lower limb movements...
February 13, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Jonathan Scharff Nielsen, Tim B Dyrby, Henrik Lundell
Molecular diffusion measured with diffusion weighted MRI (DWI) offers a probe for tissue microstructure. However, inferring microstructural properties from conventional DWI data is a complex inverse problem and has to account for heterogeneity in sizes, shapes and orientations of the tissue compartments contained within an imaging voxel. Alternative experimental means for disentangling the signal signatures of such features could provide a stronger link between the data and its interpretation. Double diffusion encoding (DDE) offers the possibility to factor out variation in compartment shapes from orientational dispersion of anisotropic domains by measuring the correlation between diffusivity in multiple directions...
February 13, 2018: Scientific Reports
Hanna Sanyour, Josh Childs, Gerald A Meininger, Zhongkui Hong
Atomic force microscopy (AFM) is an attractive technique for studying biomechanical and morphological changes in live cells. Using real-time AFM monitoring of cellular mechanical properties, spontaneous oscillations in cell stiffness and cell adhesion to the extracellular matrix (ECM) have been found. However, the lack of automated analytical approaches to systematically extract oscillatory signals, and noise filtering from a large set of AFM data, is a significant obstacle when quantifying and interpreting the dynamic characteristics of live cells...
February 13, 2018: Scientific Reports
Gabriel Oh, Sasha Ebrahimi, Matthew Carlucci, Aiping Zhang, Akhil Nair, Daniel E Groot, Viviane Labrie, Peixin Jia, Edward S Oh, Richie H Jeremian, Miki Susic, Tenjin C Shrestha, Martin R Ralph, Juozas Gordevičius, Karolis Koncevičius, Art Petronis
Circadian rhythmicity governs a remarkable array of fundamental biological functions and is mediated by cyclical transcriptomic and proteomic activities. Epigenetic factors are also involved in this circadian machinery; however, despite extensive efforts, detection and characterization of circadian cytosine modifications at the nucleotide level have remained elusive. In this study, we report that a large proportion of epigenetically variable cytosines show a circadian pattern in their modification status in mice...
February 13, 2018: Nature Communications
Jeffrey A Swan, Susan Golden, Andy LiWang, Carrie L Partch
Circadian rhythms enable cells and organisms to coordinate their physiology with the cyclic environmental changes that come as a result of Earth's light/dark cycles. Cyanobacteria make use of a post-translational oscillator (PTO) to maintain circadian rhythms, and this elegant system has become an important model for the post-translational timing mechanisms. Comprised of three proteins, the KaiABC system undergoes an oscillatory biochemical cycle that provides timing cues to achieve a 24-hour molecular clock...
February 13, 2018: Journal of Biological Chemistry
D V P S Murty, Vinay Shirhatti, Poojya Ravishankar, Supratim Ray
Recent studies have shown the existence of two gamma rhythms in the hippocampus subserving different functions, but to date, primate studies in primary visual cortex have reported a single gamma rhythm. Here we show that large visual stimuli induce a slow gamma (25-45 Hz) in area V1 of two awake adult female bonnet monkeys and in the electroencephalogram of 15 human subjects (7 males and 8 females), in addition to the traditionally known fast gamma (45-70 Hz). The two rhythms had different tuning characteristics for stimulus orientation, contrast, drift speed and size...
February 9, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Shuo Chen, Adam Z Weitemier, Xiao Zeng, Linmeng He, Xiyu Wang, Yanqiu Tao, Arthur J Y Huang, Yuki Hashimotodani, Masanobu Kano, Hirohide Iwasaki, Laxmi Kumar Parajuli, Shigeo Okabe, Daniel B Loong Teh, Angelo H All, Iku Tsutsui-Kimura, Kenji F Tanaka, Xiaogang Liu, Thomas J McHugh
Optogenetics has revolutionized the experimental interrogation of neural circuits and holds promise for the treatment of neurological disorders. It is limited, however, because visible light cannot penetrate deep inside brain tissue. Upconversion nanoparticles (UCNPs) absorb tissue-penetrating near-infrared (NIR) light and emit wavelength-specific visible light. Here, we demonstrate that molecularly tailored UCNPs can serve as optogenetic actuators of transcranial NIR light to stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall...
February 9, 2018: Science
Dmitry Gerashchenko, Michelle A Schmidt, Mark R Zielinski, Michele E Moore, Jonathan P Wisor
Slow-wave activity (SWA) in the electroencephalogram during slow-wave sleep (SWS) varies as a function of sleep-wake history. A putative sleep-active population of neuronal nitric oxide synthase (nNOS)-containing interneurons in the cerebral cortex, defined as such by the expression of Fos in animals euthanized after protracted deep sleep, may be a local regulator of SWA. We investigated whether electrophysiological responses to activation of these cells are consistent with their role of a local regulator of SWA...
February 10, 2018: Neuroscience
Tomoaki Nakazono, Heechul Jun, Mathew Blurton-Jones, Kim N Green, Kei M Igarashi
Gamma oscillations that occur within the entorhinal cortex-hippocampal circuitry play important roles in the formation and retrieval of memory in healthy brains. Recent studies report that gamma oscillations are impaired in the entorhinal-hippocampal circuit of Alzheimer's disease (AD) patients and AD animal models. Here we review the latest advancements in studies of entorhinal-hippocampal gamma oscillations in healthy memory and dementia. This review is especially salient for readers in Alzheimer's research field not familiar with in vivo electrophysiology...
February 10, 2018: Neuroscience Research
Liya Ma, Kevin Skoblenick, Kevin Johnston, Stefan Everling
Acute administration of N-methyl-D-aspartate receptor (NMDAR) antagonists in healthy humans and animals produces working memory deficits similar to those observed in schizophrenia. However, it is unclear whether they also lead to altered low-frequency (<=60Hz) neural oscillatory activities similar to those associated with schizophrenia during working memory processes. Here we recorded local field potentials (LFPs) and single unit activity from the lateral prefrontal cortex (LPFC) of three male rhesus macaque monkeys while they performed a rule-based prosaccade and antisaccade working memory task, both before and after systemic injections of a subanesthetic dose (<=0...
February 2, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Marina Matsumiya, Takehito Tomita, Kumiko Yoshioka-Kobayashi, Akihiro Isomura, Ryoichiro Kageyama
Somites are periodically formed by segmentation of the anterior parts of the presomitic mesoderm (PSM). In the mouse embryo, this periodicity is controlled by the segmentation clock gene Hes7 , which exhibits wave-like oscillatory expression in the PSM. Despite intensive studies, the exact mechanism of such synchronous oscillatory dynamics of Hes7 expression still remains to be analyzed. Detailed analysis of the segmentation clock has been hampered because it requires the use of live embryos, and establishment of an in vitro culture system would facilitate such analyses...
February 14, 2018: Development
Stefano Vezzoli, Vincenzo Bruno, Clayton DeVault, Thomas Roger, Vladimir M Shalaev, Alexandra Boltasseva, Marcello Ferrera, Matteo Clerici, Audrius Dubietis, Daniele Faccio
Materials with a spatially uniform but temporally varying optical response have applications ranging from magnetic field-free optical isolators to fundamental studies of quantum field theories. However, these effects typically become relevant only for time variations oscillating at optical frequencies, thus presenting a significant hurdle that severely limits the realization of such conditions. Here we present a thin-film material with a permittivity that pulsates (uniformly in space) at optical frequencies and realizes a time-reversing medium of the form originally proposed by Pendry [Science 322, 71 (2008)SCIEAS0036-807510...
January 26, 2018: Physical Review Letters
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