6,767 research outputs found
Phase Dependency of the Human Primary Motor Cortex and Cholinergic Inhibition Cancelation during Beta tACS
The human motor cortex has a tendency to resonant activity at about 20 Hz so stimulation should more readily entrain neuronal populations at this frequency. We investigated whether and how different interneuronal circuits contribute to such resonance by using transcranial magnetic stimulation (TMS) during transcranial alternating current stimulation (tACS) at motor (20 Hz) and a nonmotor resonance frequency (7 Hz). We tested different TMS interneuronal protocols and triggered TMS pulses at different tACS phases. The effect of cholinergic short-latency afferent inhibition (SAI) was abolished by 20 Hz tACS, linking cortical beta activity to sensorimotor integration. However, this effect occurred regardless of the tACS phase. In contrast, 20 Hz tACS selectively modulated MEP size according to the phase of tACS during single pulse, GABAAergic short-interval intracortical inhibition (SICI) and glutamatergic intracortical facilitation (ICF). For SICI this phase effect was more marked during 20 Hz stimulation. Phase modulation of SICI also depended on whether or not spontaneous beta activity occurred at ~20 Hz, supporting an interaction effect between tACS and underlying circuit resonances. The present study provides in vivo evidence linking cortical beta activity to sensorimotor integration, and for beta oscillations in motor cortex being promoted by resonance in GABAAergic interneuronal circuits
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Cognitive and behavioral improvement in adults with fragile X syndrome treated with metformin-two cases.
BackgroundThe majority of individuals with fragile X syndrome (FXS) have intellectual disability, behavioral problems, autism, and language deficits. IQ typically declines with age in boys with the full mutation. The results of preclinical studies demonstrated that metformin, a biguanide used to treat type 2 diabetes, rescues multiple phenotypes of FXS in both Drosophila and mouse models. Preliminary studies of patients with FXS demonstrated improvements in behavior.MethodsHere, we present two cases of individuals who have been treated with metformin clinically for one year.ResultsBoth patients demonstrated significant cognitive and behavioral improvements. They also improved eating habits and normalization of their weight percentiles.ConclusionMetformin may be a candidate drug for treatment of several types of symptoms in individuals with FXS
COMPARING PRICES OF BASIC NEEDS (FOODS AND HOUSES): A CASE STUDY OF CHANGLUN, KODIANG AND JITRA
Recently, the price of goods and services including the basic needs (foods and houses) in Malaysia are increasing slightly. Based on random interviews, there are complaints from low level income community of Changlun claiming that the price of basic needs especially foods and houses in Changlun are more expensive than Kodiang and Jitra. The purpose of this community based study is to investigate the claim of the low level income community whom are majority in Changlun. An observational study was conducted for 6 weeks by collecting actual prices of basic needs (foods and houses) in Changlun, Kodiang and Jitra. Exploratory Data Analysis (EDA) was used to compare the prices. The findings indicated that there exist price disparity of basic needs among Changlun, Kodiang and Jitra. Based on the samples taken, Changlun has the highest prices for foods. However, the prices were still within the price range of Kementerian Perdagangan Dalam Negeri, Koperasi dan Kepenggunaan (KPDNKK). Changlun also has the highest house price with the price disparity of RM18,000 and RM90,000 as compared to Jitra and Kodiang respectively. Further investigations needed to collect more data to generalise this issue and before actions can be taken to assist the low level income community in Changlun to cope with the price hike and survive day to day basis.Keywords: Basic needs, prices, communit
Point Mutations in Centromeric Histone Induce Post-zygotic Incompatibility and Uniparental Inheritance.
The centromeric histone 3 variant (CENH3, aka CENP-A) is essential for the segregation of sister chromatids during mitosis and meiosis. To better define CENH3 functional constraints, we complemented a null allele in Arabidopsis with a variety of mutant alleles, each inducing a single amino acid change in conserved residues of the histone fold domain. Many of these transgenic missense lines displayed wild-type growth and fertility on self-pollination, but exhibited frequent post-zygotic death and uniparental inheritance when crossed with wild-type plants. The failure of centromeres marked by these missense mutation in the histone fold domain of CENH3 reproduces the genome elimination syndromes described with chimeric CENH3 and CENH3 from diverged species. Additionally, evidence that a single point mutation is sufficient to generate a haploid inducer provide a simple one-step method for the identification of non-transgenic haploid inducers in existing mutagenized collections of crop species. As proof of the extreme simplicity of this approach to create haploid-inducing lines, we performed an in silico search for previously identified point mutations in CENH3 and identified an Arabidopsis line carrying the A86V substitution within the histone fold domain. This A87V non-transgenic line, while fully fertile on self-pollination, produced postzygotic death and uniparental haploids when crossed to wild type
Massive Star Formation
The enormous radiative and mechanical luminosities of massive stars impact a
vast range of scales and processes, from the reionization of the universe, to
the evolution of galaxies, to the regulation of the interstellar medium, to the
formation of star clusters, and even to the formation of planets around stars
in such clusters. Two main classes of massive star formation theory are under
active study, Core Accretion and Competitive Accretion. In Core Accretion, the
initial conditions are self-gravitating, centrally concentrated cores that
condense with a range of masses from the surrounding, fragmenting clump
environment. They then undergo relatively ordered collapse via a central disk
to form a single star or a small-N multiple. In this case, the pre-stellar core
mass function has a similar form to the stellar initial mass function. In
Competitive Accretion, the material that forms a massive star is drawn more
chaotically from a wider region of the clump without passing through a phase of
being in a massive, coherent core. In this case, massive star formation must
proceed hand in hand with star cluster formation. If stellar densities become
very high near the cluster center, then collisions between stars may also help
to form the most massive stars. We review recent theoretical and observational
progress towards understanding massive star formation, considering physical and
chemical processes, comparisons with low and intermediate-mass stars, and
connections to star cluster formation.Comment: Accepted for publication as a chapter in Protostars and Planets VI,
University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C.
Dullemond, Th. Hennin
Troponin T3 regulates nuclear localization of the calcium channel Cavβ1a subunit in skeletal muscle
The voltage-gated calcium channel (Cav) β1a subunit (Cavβ1a) plays an important role in excitation-contraction coupling (ECC), a process in the myoplasm that leads to muscle-force generation. Recently, we discovered that the Cavβ1a subunit travels to the nucleus of skeletal muscle cells where it helps to regulate gene transcription. To determine how it travels to the nucleus, we performed a yeast two-hybrid screening of the mouse fast skeletal muscle cDNA library and identified an interaction with troponin T3 (TnT3), which we subsequently confirmed by co-immunoprecipitation and co-localization assays in mouse skeletal muscle in vivo and in cultured C2C12 muscle cells. Interacting domains were mapped to the leucine zipper domain in TnT3 COOH-terminus (160-244 aa) and Cavβ1a NH2-terminus (1-99 aa), respectively. The double fluorescence assay in C2C12 cells co-expressing TnT3/DsRed and Cavβ1a/YFP shows that TnT3 facilitates Cavβ1a nuclear recruitment, suggesting that the two proteins play a heretofore unknown role during early muscle differentiation in addition to their classical role in ECC regulation.Fil: Zhang, Tan. Wake Forest School of Medicine; Estados UnidosFil: Taylor, Jackson. Wake Forest School of Medicine; Estados UnidosFil: Jiang, Yang. Wake Forest School of Medicine; Estados UnidosFil: Pereyra, Andrea Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Messi, Maria Laura. Wake Forest School of Medicine; Estados UnidosFil: Wang, Zhong Min. Wake Forest School of Medicine; Estados UnidosFil: Hereñú, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Delbono, Osvaldo. Wake Forest School of Medicine; Estados Unido
Average power and burst analysis revealed complementary information on drug-related changes of motor performance in Parkinson's disease
In patients with Parkinson's disease (PD), suppression of beta and increase in gamma oscillations in the subthalamic nucleus (STN) have been associated with both levodopa treatment and motor functions. Recent results suggest that modulation of the temporal dynamics of theses oscillations (bursting activity) might contain more information about pathological states and behaviour than their average power. Here we directly compared the information provided by power and burst analyses about the drug-related changes in STN activities and their impact on motor performance within PD patients. STN local field potential (LFP) signals were recorded from externalized patients performing self-paced movements ON and OFF levodopa. When normalised across medication states, both power and burst analyses showed an increase in low-beta oscillations in the dopamine-depleted state during rest. When normalised within-medication state, both analyses revealed that levodopa increased movement-related modulation in the alpha and low-gamma bands, with higher gamma activity around movement predicting faster reaches. Finally, burst analyses helped to reveal opposite drug-related changes in low- and high-beta frequency bands, and identified additional within-patient relationships between high-beta bursting and movement performance. Our findings suggest that although power and burst analyses share a lot in common they also provide complementary information on how STN-LFP activity is associated with motor performance, and how levodopa treatment may modify these relationships in a way that helps explain drug-related changes in motor performance. Different ways of normalisation in the power analysis can reveal different information. Similarly, the burst analysis is sensitive to how the threshold is defined - either for separate medication conditions separately, or across pooled conditions. In addition, the burst interpretation has far-reaching implications about the nature of neural oscillations - whether the oscillations happen as isolated burst-events or are they sustained phenomena with dynamic amplitude variations? This can be different for different frequency bands, and different for different medication states even for the same frequency band
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