Sleep-State Dependent Alterations in Brain Functional Connectivity under Urethane Anesthesia in a Rat Model of Early-Stage Parkinson's Disease

Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra, leading to striatal dopamine depletion. A partial unilateral striatal 6-hydroxydopamine (6-OHDA) lesion causes 40-60% dopamine depletion in the lesioned rat striatum, modeling the early stage of PD. In this study, we explored the connectivity between the brain regions in partially 6-OHDA lesioned male Wistar rats under urethane anesthesia using functional magnetic resonance imaging (fMRI) at 5 weeks after the 6-OHDA infusion. Under urethane anesthesia, the brain fluctuates between the two states, resembling rapid eye movement (REM) and non-REM sleep states. We observed clear urethane-induced sleep-like states in 8/19 lesioned animals and 8/18 control animals. 6-OHDA lesioned animals exhibited significantly lower functional connectivity between the brain regions. However, we observed these differences only during the REM-like sleep state, suggesting the involvement of the nigrostriatal dopaminergic pathway in REM sleep regulation. Corticocortical and corticostriatal connections were decreased in both hemispheres, reflecting the global effect of the lesion. Overall, this study describes a promising model to study PD-related sleep disorders in rats using fMRI.Peer reviewe

Study of D0 --> pi- e+ nu(e), D+ --> pi0 e+ nu(e), D0 --> K- e+ nu(e), and D+ --> anti-K0 e+ nu(e) in Tagged Decays of the psi(3770) Resonance

Using psi(3770) --> DDbar events collected with the CLEO-c detector at the Cornell e+ e- storage ring, tagged by fully reconstructing one D meson in a hadronic decay mode, we measure absolute branching fractions and differential decay rates for D0 --> pi- e+ nu(e), D+ --> pi0 e+ nu(e), D0 --> K- e+ nu(e), and D+ --> anti-K0 e+ nu(e). The measured decay rates are used to study semileptonic form factors governing these transitions and to test unquenched Lattice QCD (LQCD) calculations. We average our results with previously published CLEO-c measurements of the same quantities using a neutrino reconstruction technique. Combining LQCD calculations of form factor absolute normalizations f+(0) and measurements of f(pi)+(0)*|Vcd| and f(K)+(0)*|Vcs|, we find |Vcd| = 0.223(8)(3)(23) and |Vcs| = 1.019(10)(7)(106), where the uncertainties are statistical, experimental systematic, and from LQCD, respectively.Comment: 47 pages, 9 Figures, available through http://www.lns.cornell.edu/public/CLNS

Oscillation Phase Dynamics In The Belousov-Zhabotinsky Reaction. Implementation To Image Processing.

The phase jumps dynamics in a photosensitive Belousov- Zhabotinsky reaction has been studied. It was found that an initially inhomogeneous phase distribution evolved to a homogeneous one, so that the phase at phase-lag points rises to the value at phase-lead points. A steep phase distribution was shown to become smoother in the course of time, inducing a dephasing wave which restores the system to a uniform phase. Applications of photosensitive chemical reactions to image processing (image storage, inversing, contouring) are discussed. Acknowledgments. Many thanks to Drs. Vadim N. Biktashev and Mikhail R. Stepanov for helpful discussions of the subject; special acknowledgments to Professor Arthur T. Winfree who read the manuscript carefully and helped in its structure improvement. Introduction A number of processes in solid state physics, theory of lasers, chemistry and biology can be described in terms of the theory of coupled oscillators [1]. Autooscillating chemical reactions, su..

STUDYING THE DYNAMICS OF THE SELF-WAVE VORTEXES IN THE CHEMICAL TO BE EXCITATED MEDIUM ON THE BASE OF REACTION OF BELOUSOV-ZHABOTINSKY

For the first time, obtained experimentally have been the three-dimensional twisted vortex and superspiral wave. Its dynamics has been studied. The new methods of receiving the main types of the three-dimensional self-wave vortexes have been developed. The field of application: the self-wave processes in the physical, chemical and biological systemsAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Phase-Rotors in an Active Medium

Vortices of unusual form (rotating straight lines), phase-rotors, are found to occur in an active medium. Transitions between phase-rotors and Archimedian spiral waves are studied. The role of the dispersion relation in vortex development is discussed. Rotating nonlinear waves in active media have been attracting attention of the researchers during several decades. Such waves are found to occur in numerous physical, biological and chemical systems. The well documented examples are heart muscle and the BelousovZhabotinsky (BZ) reaction. Despite different physical nature, these systems have similar properties of active media (see, for example, ref.[1], where there is a comparison of dimensionless parameters of the heart tissue and the BZ reaction). Ever since vortices in the form of rotating Archimedian spirals were observed in the Belousov-Zhabotinsky reaction [2, 3, 4], these have been regarded as the only type of vortices phase-rotors in an active medium 2 in a two-dimensional excit..

A Simple Two-Variable Model of Cardiac Excitation

We modified the FitzHugh-Nagumo model of an excitable medium so that it describes adequately the dynamics of pulse propagation in the canine myocardium. The modified model is simple enough to be used for intensive three-dimensional computations of the whole heart. It simulates the pulse shape and the restitution property of the canine myocardium with good precision. In 1952 Hodgkin and Huxley proposed the first quantitative mathematical model of wave propagation in squid nerve [1]. This work has had a great impact on modeling of various nonlinear phenomena in biology. On the basis of this model Noble in 1962 developed the first physiological model of cardiac E-mail: [email protected]; permanent address: Institute of Theoretical and Experimental Biophysics, Puschino, Moscow Region, 142292 Russia A simple model of cardiac excitation 2 tissue [2]. Further studies in this field resulted in the development of several realistic ionic models of cardiac tissue which were derived from ..

Dynamics of the Oscillation Phase Distribution in the BZ Reaction.

Oscillation phase dynamics in the homogeneous autooscillating Belousov-Zhabotinsky (BZ) reaction has been studied by computer simulations. The wave dynamics in autooscillating media is qualitatively different from those in excitable media for sufficiently long waves. We propose a classification of chemical waves which is based on the analysis of shape of the dispersion curve. This delimits conventionally the waves with properties analogous to those in excitable media - "trigger waves", from "phase waves". In particular, we study the phenomenon of "dephasing wave", recently observed experimentally [27]. This is a special form of phase wave dynamics, which looks like a propagating wave of phase triggering towards a uniform value. We show, that phase wave dynamics, including the dephasing waves, can be described in terms of the phase diffusion equation, the well known Burgers equation. This description remains qualitatively valid for a wide range of wavelengths. Acknowledgments. This wor..