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Alexei L Vyssotski, Anna E Stepien, Georg B Keller, Richard H R Hahnloser
What cortical inputs are provided to motor control areas while they drive complex learned behaviors? We study this question in the nucleus interface of the nidopallium (NIf), which is required for normal birdsong production and provides the main source of auditory input to HVC, the driver of adult song. In juvenile and adult zebra finches, we find that spikes in NIf projection neurons precede vocalizations by several tens of milliseconds and are insensitive to distortions of auditory feedback. We identify a local isometry between NIf output and vocalizations: quasi-identical notes produced in different syllables are preceded by highly similar NIf spike patterns...
October 2016: PLoS Biology
William A Liberti, Jeffrey E Markowitz, L Nathan Perkins, Derek C Liberti, Daniel P Leman, Grigori Guitchounts, Tarciso Velho, Darrell N Kotton, Carlos Lois, Timothy J Gardner
Motor skills can be maintained for decades, but the biological basis of this memory persistence remains largely unknown. The zebra finch, for example, sings a highly stereotyped song that is stable for years, but it is not known whether the precise neural patterns underlying song are stable or shift from day to day. Here we demonstrate that the population of projection neurons coding for song in the premotor nucleus, HVC, change from day to day. The most dramatic shifts occur over intervals of sleep. In contrast to the transient participation of excitatory neurons, ensemble measurements dominated by inhibition persist unchanged even after damage to downstream motor nerves...
October 10, 2016: Nature Neuroscience
Varvara A Kirchner, Shin Hwang, Gi-Won Song, Chul-Soo Ahn, Deok-Bog Moon, Ki-Hun Kim, Dong-Hwan Jung, Tae-Yong Ha, Gil-Chun Park, Sung-Gyu Lee
BACKGROUND The middle hepatic vein (MHV) interposition vessel graft (IVG) is often occluded within a few months after living-donor liver transplantation (LDLT). We aimed to assess the mechanisms of resolving the hepatic venous congestion (HVC) that develops after gradual occlusion of the MHV-IVG. MATERIAL AND METHODS This study comprised two parts. Part I involved an assessment of the process of HVC resolution in the remnant right liver after donation of an extended left liver graft (n=100). Part II involved an evaluation of the timing and patterns of gradual MHV-IVG occlusion and HVC resolution in LDLT recipients (n=100)...
October 7, 2016: Annals of Transplantation: Quarterly of the Polish Transplantation Society
Julie Hamaide, Geert De Groof, Gwendolyn Van Steenkiste, Ben Jeurissen, Johan Van Audekerke, Maarten Naeyaert, Lisbeth Van Ruijssevelt, Charlotte Cornil, Jan Sijbers, Marleen Verhoye, Annemie Van der Linden
Zebra finches are an excellent model to study the process of vocal learning, a complex socially-learned tool of communication that forms the basis of spoken human language. So far, structural investigation of the zebra finch brain has been performed ex vivo using invasive methods such as histology. These methods are highly specific, however, they strongly interfere with performing whole-brain analyses and exclude longitudinal studies aimed at establishing causal correlations between neuroplastic events and specific behavioral performances...
September 30, 2016: NeuroImage
Dulce María Figueroa-Castro, Guadalupe González-Tochihuitl, Sombra Patricia Rivas-Arancibia, Gabriela Castaño-Meneses
We describe the spatial variation in the structure and composition of the communities of insects visiting the inflorescences of Flaveria ramosissima Klatt, Florestina pedata (Cav.) Cass., and Parthenium bipinnatifidum (Ort.) Rollins (Asteraceae) in a xeric environment in Central Mexico. Inflorescences of the three Asteraceae were visited by a total of 96 species of Hymenoptera, Diptera, Lepidoptera, Coleoptera, and Hemiptera. Total species richness of floral visitors to the three Asteraceae and total abundance of insects of Fl...
September 30, 2016: Environmental Entomology
Sander R Raymaekers, Wout Verbeure, Sita M Ter Haar, Charlotte A Cornil, Jacques Balthazart, Veerle M Darras
The zebra finch (Taeniopygia guttata) song control system consists of several series of interconnected brain nuclei that undergo marked changes during ontogeny and sexual development, making it an excellent model to study developmental neuroplasticity. Despite the demonstrated influence of hormones such as sex steroids on this phenomenon, thyroid hormones (THs) - an important factor in neural development and maturation - have not been studied in this regard. We used in situ hybridization to compare the expression of TH transporters, deiodinases and receptors between both sexes during all phases of song development in male zebra finch...
September 29, 2016: General and Comparative Endocrinology
Nirag Kadakia, Eve Armstrong, Daniel Breen, Uriel Morone, Arij Daou, Daniel Margoliash, Henry D I Abarbanel
With the goal of building a model of the HVC nucleus in the avian song system, we discuss in detail a model of HVC[Formula: see text] projection neurons comprised of a somatic compartment with fast Na[Formula: see text] and K[Formula: see text] currents and a dendritic compartment with slower Ca[Formula: see text] dynamics. We show this model qualitatively exhibits many observed electrophysiological behaviors. We then show in numerical procedures how one can design and analyze feasible laboratory experiments that allow the estimation of all of the many parameters and unmeasured dynamical variables, given observations of the somatic voltage [Formula: see text] alone...
September 29, 2016: Biological Cybernetics
Alain Nogaret, C Daniel Meliza, Daniel Margoliash, Henry D I Abarbanel
We report on the construction of neuron models by assimilating electrophysiological data with large-scale constrained nonlinear optimization. The method implements interior point line parameter search to determine parameters from the responses to intracellular current injections of zebra finch HVC neurons. We incorporated these parameters into a nine ionic channel conductance model to obtain completed models which we then use to predict the state of the neuron under arbitrary current stimulation. Each model was validated by successfully predicting the dynamics of the membrane potential induced by 20-50 different current protocols...
2016: Scientific Reports
Rachel E Cohen, Matheus Macedo-Lima, Kimberly E Miller, Eliot A Brenowitz
UNLABELLED: Seasonally breeding songbirds exhibit pronounced annual changes in song behavior, and in the morphology and physiology of the telencephalic neural circuit underlying production of learned song. Each breeding season, new adult-born neurons are added to the pallial nucleus HVC in response to seasonal changes in steroid hormone levels, and send long axonal projections to their target nucleus, the robust nucleus of the arcopallium (RA). We investigated the role that adult neurogenesis plays in the seasonal reconstruction of this circuit...
August 24, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Eve Armstrong, Henry D I Abarbanel
We propose a functional architecture of the adult songbird nucleus HVC in which the core element is a "functional syllable unit" (FSU). In this model, HVC is organized into FSUs, each of which provides the basis for the production of one syllable in vocalization. Within each FSU, the inhibitory neuron population takes one of two operational states: (A) simultaneous firing wherein all inhibitory neurons fire simultaneously, and (B) competitive firing of the inhibitory neurons. Switching between these basic modes of activity is accomplished via changes in the synaptic strengths among the inhibitory neurons...
August 17, 2016: Journal of Neurophysiology
Robert Zilberszac, Patrizio Lancellotti, Dan Gilon, Harald Gabriel, Michael Schemper, Gerald Maurer, Massimo Massetti, Raphael Rosenhek
AIMS: We sought to assess the efficacy of a heart valve clinic (HVC) follow-up programme for patients with severe aortic stenosis (AS). METHODS AND RESULTS: Three hundred and eighty-eight consecutive patients with AS (age 71 ± 10 years; aortic-jet velocity 5.1 ± 0.6 m/s) and an indication for aortic valve replacement (AVR) were included. Of these, 290 patients presented with an indication for surgery at their first visit at the HVC and 98 asymptomatic patients who had been enrolled in an HVC monitoring programme developed indications for surgery during follow-up...
August 12, 2016: European Heart Journal Cardiovascular Imaging
Kristofer E Bouchard, Michael S Brainard
Predicting future events is a critical computation for both perception and behavior. Despite the essential nature of this computation, there are few studies demonstrating neural activity that predicts specific events in learned, probabilistic sequences. Here, we test the hypotheses that the dynamics of internally generated neural activity are predictive of future events and are structured by the learned temporal-sequential statistics of those events. We recorded neural activity in Bengalese finch sensory-motor area HVC in response to playback of sequences from individuals' songs, and examined the neural activity that continued after stimulus offset...
August 23, 2016: Proceedings of the National Academy of Sciences of the United States of America
N Mikołajczyk-Korniak, O Tronina, K Ślubowska, A Perkowska-Ptasińska, M Pacholczyk, T Bączkowska, M Durlik
BACKGROUND: Assessment of the dynamics and degree of liver fibrosis in patients after liver transplantation is a basic element in the process of determining transplant survival prognosis. It allows planning and early initiation of prophylaxis or treatment, which translates into increased chances of preventing cirrhosis and of long-term optimal function of the graft. The aim of this study was to compare the results of biopsy and dynamic elastography in diagnostics of transplanted liver fibrosis, as well as determination of the stiffness cut-off point for assessment of significant fibrosis...
June 2016: Transplantation Proceedings
Hae Jin Kim, Hae Young Yoo, Hai Yue Lin, Goo Taeg Oh, Yin Hua Zhang, Sung Joon Kim
We previously reported that hypoxia augments α-adrenergic contraction (hypoxic vasoconstriction, HVC) of skeletal arteries in rats. The underlying mechanism may involve hypoxic inhibition of endothelial nitric oxide synthase (eNOS) expressed in skeletal arterial myocytes (16). To further explore the novel role of muscular eNOS in the skeletal artery, we compared HVC in femoral arteries (FAs) from eNOS knockout (KO) mice with that from wild-type (WT) and heterozygous (HZ) mice. Immunohistochemical assays revealed that, in addition to endothelia, eNOS is also expressed in the medial layer of FAs, albeit at a much lower level...
September 1, 2016: American Journal of Physiology. Cell Physiology
Georgia K Longmoor, C Henrik Lange, Hannah Darvell, Lauren Walker, Seppo Rytkönen, Emma Vatka, Esa Hohtola, Markku Orell, Tom V Smulders
In most species of seasonally breeding songbirds studied to date, the brain areas that control singing (i.e. the song control system, SCS) are larger during the breeding season than at other times of the year. In the family of titmice and chickadees (Paridae), one species, the blue tit (Cyanistes caeruleus), shows the typical pattern of seasonal changes, while another species, the black-capped chickadee (Poecile atricapillus), shows, at best, very reduced seasonal changes in the SCS. To test whether this pattern holds up in the two Parid lineages to which these two species belong, and to rule out that the differences in seasonal patterns observed were due to differences in geography or laboratory, we compared the seasonal patterns in two song system nuclei volumes (HVC and Area X) in willow tits (Poecile montanus), closely related to black-capped chickadees, and in great tits (Parus major), more closely related to blue tits, from the same area around Oulu, Finland...
2016: Brain, Behavior and Evolution
Zhi-Lian Li, Chao-Sheng He, Yuan-Han Chen, Xin-Ling Liang, Wei Dong, Rui-Zhao Li, Si-Jia Li, Li-Xia Xu, Zhong-Lin Feng, Hua-Ban Liang, Li-Fen Wang, Wei Shi
OBJECTIVE: To investigate the impact of heart valve calcification (HVC) on cardiovascular outcomes in patients on maintenance hemodialysis (MHD). METHODS: We enrolled 302 Chinese patients on MHD between 2009 and 2011 including 99 with HVC identified by echocardiography screening. All the patients were followed up for 2 years and survival analysis was performed with all-cause mortality, cardiovascular mortality and new onset cardiovascular events as the endpoints...
June 20, 2016: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Kosuke Hamaguchi, Masashi Tanaka, Richard Mooney
How do forebrain and brainstem circuits interact to produce temporally precise and reproducible behaviors? Birdsong is an elaborate, temporally precise, and stereotyped vocal behavior controlled by a network of forebrain and brainstem nuclei. An influential idea is that song premotor neurons in a forebrain nucleus (HVC) form a synaptic chain that dictates song timing in a top-down manner. Here we combine physiological, dynamical, and computational methods to show that song timing is not generated solely by a mechanism localized to HVC but instead is the product of a distributed and recurrent synaptic network spanning the forebrain and brainstem, of which HVC is a component...
August 3, 2016: Neuron
Naomi Shin, Young H Kim, Hao Xu, Hai-Bin Shi, Qing-Qiao Zhang, Jean Paul Colon Pons, Ducksoo Kim, Yi Xu, Fei-Yun Wu, Samuel Han, Byung-Boong Lee, Lin-Sun Li
AIM: To re-examine whether hepatic vein thrombosis (HVT) (classical Budd-Chiari syndrome) and hepatic vena cava-Budd Chiari syndrome (HVC-BCS) are the same disorder. METHODS: A systematic review of observational studies conducted in adult subjects with primary BCS, hepatic vein outflow tract obstruction, membranous obstruction of the inferior vena cava (IVC), obliterative hepatocavopathy, or HVT during the period of January 2000 until February 2015 was conducted using the following databases: Cochrane Library, CINAHL, MEDLINE, PubMed and Scopus...
June 8, 2016: World Journal of Hepatology
Saša Rapan, Karin Krnić, Vjeran Rapan, Vjekoslav Kolarević
Aim To evaluate the effectiveness and complication of vertebroplasty with high viscosity cement (HVC). Methods The patients with intensive pain caused by a fractured vertebrae were treated by application of HVC into the vertebral body, through unilateral transpedicular approach. The application was performed in 422 patients (221 were treated for osteoporosis and 201 for malignancy) on 846 vertebrae. Results Preoperative Visual Analogue Scale (VAS) score was 8.35 and 2.21 (p<0.00001) 24 hours after surgery and 3 months later, respectively...
August 1, 2016: Medicinski Glasnik
Tianyuan Tan, Shuan Dong, Yingwei Huang, Jian Liu, Jian Le, Kaipei Liu
With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG) interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD) and harmonic voltage compensator (HVC) based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents...
2016: PloS One
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