for Journals by Title or ISSN
for Articles by Keywords
help

Publisher: Springer-Verlag   (Total: 2210 journals)

 A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

  First | 2 3 4 5 6 7 8 9 | Last

Current Obesity Reports     Partially Free   (Followers: 2)
Current Obstetrics and Gynecology Reports     Hybrid Journal   (Followers: 2)
Current Oncology Reports     Hybrid Journal   (Followers: 1, SJR: 1.144, h-index: 31)
Current Ophthalmology Reports     Hybrid Journal   (Followers: 3)
Current Oral Health Reports     Hybrid Journal  
Current Osteoporosis Reports     Hybrid Journal   (Followers: 1, SJR: 0.896, h-index: 20)
Current Otorhinolaryngology Reports     Hybrid Journal  
Current Pain and Headache Reports     Hybrid Journal   (Followers: 2, SJR: 0.463, h-index: 32)
Current Pathobiology Reports     Hybrid Journal  
Current Pediatrics Reports     Hybrid Journal   (Followers: 1)
Current Physical Medicine and Rehabilitation Reports     Hybrid Journal   (Followers: 3)
Current Prostate Reports     Hybrid Journal   (Followers: 1)
Current Psychiatry Reports     Hybrid Journal   (Followers: 4, SJR: 1.232, h-index: 38)
Current Psychological Research     Hybrid Journal   (Followers: 7)
Current Psychology     Hybrid Journal   (Followers: 11, SJR: 0.278, h-index: 21)
Current Radiology Reports     Hybrid Journal   (Followers: 1)
Current Respiratory Care Reports     Hybrid Journal   (Followers: 1)
Current Reviews in Musculoskeletal Medicine     Open Access   (Followers: 7, SJR: 0.437, h-index: 8)
Current Rheumatology Reports     Hybrid Journal   (SJR: 0.889, h-index: 37)
Current Sexual Health Reports     Hybrid Journal   (Followers: 2)
Current Surgery Reports     Hybrid Journal  
Current Sustainable/Renewable Energy Reports     Hybrid Journal   (Followers: 2)
Current Topics in Microbiology and Immunology     Hybrid Journal   (Followers: 3, SJR: 1.689, h-index: 78)
Current Transplantation Reports     Hybrid Journal  
Current Treatment Options in Allergy     Hybrid Journal  
Current Treatment Options in Cardiovascular Medicine     Hybrid Journal   (SJR: 0.363, h-index: 12)
Current Treatment Options in Gastroenterology     Hybrid Journal   (Followers: 4)
Current Treatment Options in Infectious Diseases     Hybrid Journal  
Current Treatment Options in Neurology     Hybrid Journal   (Followers: 1, SJR: 0.659, h-index: 20)
Current Treatment Options in Oncology     Hybrid Journal   (Followers: 1, SJR: 0.825, h-index: 32)
Current Treatment Options in Psychiatry     Hybrid Journal  
Current Tropical Medicine Reports     Hybrid Journal  
Current Urology Reports     Hybrid Journal   (Followers: 2, SJR: 0.631, h-index: 24)
Customer Needs and Solutions     Hybrid Journal  
Cybernetics and Systems Analysis     Hybrid Journal   (Followers: 1, SJR: 0.2, h-index: 8)
Cytology and Genetics     Hybrid Journal   (Followers: 1)
Cytotechnology     Hybrid Journal   (Followers: 6, SJR: 0.394, h-index: 33)
Czechoslovak Mathematical J.     Hybrid Journal   (SJR: 0.315, h-index: 16)
Dairy Science & Technology     Hybrid Journal   (Followers: 6, SJR: 0.616, h-index: 38)
Dao     Hybrid Journal   (Followers: 3, SJR: 0.222, h-index: 4)
Data Mining and Knowledge Discovery     Hybrid Journal   (Followers: 24, SJR: 2.235, h-index: 58)
Datenbank-Spektrum     Hybrid Journal  
Datenschutz und Datensicherheit - DuD     Hybrid Journal  
De Economist     Hybrid Journal   (Followers: 7, SJR: 0.592, h-index: 14)
Debates in Neuroscience     Hybrid Journal   (Followers: 4)
Decisions in Economics and Finance     Hybrid Journal   (Followers: 7, SJR: 0.138, h-index: 8)
Demography     Hybrid Journal   (Followers: 7, SJR: 2.146, h-index: 71)
Denkbeeld     Hybrid Journal  
Der Anaesthesist     Hybrid Journal   (Followers: 4, SJR: 0.276, h-index: 34)
Der Chirurg     Hybrid Journal   (SJR: 0.223, h-index: 37)
Der Diabetologe     Hybrid Journal   (SJR: 0.122, h-index: 5)
Der Freie Zahnarzt     Hybrid Journal  
Der Gastroenterologe     Hybrid Journal   (SJR: 0.101, h-index: 3)
Der Gynakologe     Hybrid Journal   (SJR: 0.115, h-index: 10)
Der Hautarzt     Hybrid Journal   (Followers: 2, SJR: 0.258, h-index: 28)
Der Internist     Hybrid Journal   (Followers: 2, SJR: 0.165, h-index: 13)
der junge zahnarzt     Hybrid Journal  
Der Kardiologe     Hybrid Journal   (Followers: 1, SJR: 0.158, h-index: 5)
der markt     Hybrid Journal  
Der MKG-Chirurg     Hybrid Journal  
Der Nephrologe     Hybrid Journal   (Followers: 1, SJR: 0.103, h-index: 3)
Der Nervenarzt     Hybrid Journal   (SJR: 0.234, h-index: 33)
Der Onkologe     Hybrid Journal   (SJR: 0.127, h-index: 10)
Der Ophthalmologe     Hybrid Journal   (Followers: 1, SJR: 0.363, h-index: 29)
Der Orthop├Ąde     Hybrid Journal   (Followers: 4, SJR: 0.262, h-index: 32)
Der Pathologe     Hybrid Journal   (SJR: 0.196, h-index: 18)
Der Pneumologe     Hybrid Journal   (Followers: 1, SJR: 0.108, h-index: 4)
Der Radiologe     Hybrid Journal   (SJR: 0.176, h-index: 27)
Der Schmerz     Hybrid Journal   (SJR: 0.332, h-index: 26)
Der Unfallchirurg     Hybrid Journal   (Followers: 4, SJR: 0.307, h-index: 38)
Der Urologe     Hybrid Journal   (Followers: 2, SJR: 0.182, h-index: 19)
Design Automation for Embedded Systems     Hybrid Journal   (Followers: 1, SJR: 0.207, h-index: 20)
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 4, SJR: 0.969, h-index: 33)
Development Genes and Evolution     Hybrid Journal   (Followers: 3, SJR: 0.854, h-index: 53)
Diabetes Therapy     Open Access   (Followers: 6, SJR: 0.192, h-index: 2)
Diabetologia     Hybrid Journal   (Followers: 169, SJR: 2.596, h-index: 150)
Diabetologia Notes de lecture     Hybrid Journal  
Diabetology Intl.     Hybrid Journal   (Followers: 1)
Dialectical Anthropology     Hybrid Journal   (Followers: 6, SJR: 0.109, h-index: 7)
Die Weltwirtschaft     Hybrid Journal   (Followers: 2)
Differential Equations     Hybrid Journal   (Followers: 2, SJR: 0.28, h-index: 14)
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 1, SJR: 0.337, h-index: 5)
Digestive Diseases and Sciences     Hybrid Journal   (Followers: 4, SJR: 0.803, h-index: 84)
Directieve therapie     Hybrid Journal  
Discrete & Computational Geometry     Hybrid Journal   (Followers: 1, SJR: 1.088, h-index: 37)
Discrete Event Dynamic Systems     Hybrid Journal   (Followers: 2, SJR: 1.028, h-index: 30)
Distributed and Parallel Databases     Hybrid Journal   (Followers: 4, SJR: 0.82, h-index: 29)
Distributed Computing     Hybrid Journal   (Followers: 1, SJR: 1.361, h-index: 29)
Documenta Ophthalmologica     Hybrid Journal   (Followers: 2, SJR: 1.418, h-index: 37)
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 2, SJR: 0.18, h-index: 8)
Doklady Biological Sciences     Hybrid Journal   (SJR: 0.193, h-index: 9)
Doklady Botanical Sciences     Hybrid Journal  
Doklady Chemistry     Hybrid Journal   (SJR: 0.261, h-index: 11)
Doklady Earth Sciences     Hybrid Journal   (SJR: 0.386, h-index: 15)
Doklady Mathematics     Hybrid Journal   (SJR: 0.299, h-index: 12)
Doklady Physical Chemistry     Hybrid Journal   (SJR: 0.316, h-index: 10)
Doklady Physics     Hybrid Journal   (Followers: 1, SJR: 0.274, h-index: 14)
Douleur et Analg├ęsie     Hybrid Journal   (SJR: 0.135, h-index: 5)
Drug Delivery and Translational Research     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 6)
Dynamic Games and Applications     Hybrid Journal   (Followers: 2)

  First | 2 3 4 5 6 7 8 9 | Last

Journal Cover Neurophysiology
   Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1573-9007 - ISSN (Online) 0090-2977
     Published by Springer-Verlag Homepage  [2210 journals]   [SJR: 0.136]   [H-I: 7]
  • Effect of Prior Instructions on Preprogrammed Reactions of Trunk Muscles
           in Individuals with and without Chronic Low Back Pain
    • Abstract: The late component of the stretch reflex occurring in humans within a 40 to 120 msec interval following a loading perturbation is qualified as a preprogrammed muscle reaction (PPR). The PPR size can be significantly modulated with prior instructions. These modifications are significantly influenced by a number of factors, in particular by the presence of pain syndromes. The objective of our study was to compare the effect of prior instructions on the PPR amplitude in the trunk muscles in individuals with chronic low back pain (LBP) compared to healthy controls. LBP is a widespread syndrome, especially in athletes. Surface EMGs were recorded from superficial trunk muscles, rectus abdominis (RA) and erector spinae (ES), in athletes suffering from chronic LBP (n = 24) and asymptomatic (healthy) athletes (n = 25). Loading perturbations (induced by dropping a weight, application of 3 kg force, ≈ 30 N, to the outstretched hand from a 8 cm height) were introduced in standing at a known time with prior instructions to “let go” for the induced perturbation or to “resist” it. The root mean square (RMS) of the EMG amplitudes within the reaction duration were compared between the two groups. Statistically significant differences were obtained when the mean PPR EMG amplitudes were compared between the LBP and control groups for the above two task instructions; this was found for both examined muscles, RA and ES (P < 0.05). Therefore, individuals with chronic LBP exhibit poorly modulated PPR amplitudes according to prior task instructions. Changes in the networks controlling automatically regulated movements and excitability of the spinal pathways could be responsible for this specificity.
      PubDate: 2014-04-20
       
  • Erratum in “Antioxidant Activity-Mediated Neuroprotective Effects of
           an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and
           Edema in Rats,”
    • PubDate: 2014-04-20
       
  • Erratum to: Functional Convergence of Thalamic and Intrinsic Projections
           to Cortical Layers 4 and 6
    • PubDate: 2014-04-20
       
  • Yurii P. Limanskii (1930–2013)
    • PubDate: 2014-04-20
       
  • Thiamine Metabolism in Neurons and Their Vital Capacity Upon the Action of
           Ethanol and Acetaldehyde
    • Abstract: We studied the sensitivity of a few reactions of thiamine metabolism in nerve cells upon the action of ethanol and acetaldehyde, as well as effects of the above-mentioned agents on vital capacity of cultured cells of different origins. Experiments were carried out on preparations of isolated nerve endings (synaptosomes), preparations of synaptosomal plasma membranes (SPMs), preparations of enzymes, and cell cultures. We estimated the ІС50 for the effects of ethanol and acetaldehyde on reactions that are the components of metabolism of the mobile thiamine pool in the cells. Ethanol in physiological concentrations inhibited the thiamine-binding activity of SPMs (ІС50 = 3.9 mM). At the same time, this agent used in the above concentrations practically did not influence the thiamine phosphate hydrolase activity of SPMs (estimated by the thiamine triphosphatase activity) and thiamine pyrophosphate kinase (TPK) activity. A product of ethanol metabolism, acetaldehyde, inhibited the thiamine triphosphatase activity with K і = 6.2 μM and the TPK activity with K і = 1.2 μM. The survival indices of cultured cells were estimated under conditions of the addition of ethanol and acetaldehyde to the medium. The cells of an astrocytic origin (line strain 1321 N1) and blood cells (line strain U937) practically did not respond to the presence of ethanol or acetaldehyde even in rather high concentrations in the culture medium. Under conditions of primary culture, neuron-like (differentiated) cultured РС-12 cells and also cerebellar granular neurons responded by significant decreases in the index of vital capacity to the addition of the above agents.
      PubDate: 2014-04-20
       
  • Spectral Characteristics of the Ongoing Electroencephalogram in Children
           Suffering from Visual Dysfunctions
    • Abstract: We recorded ongoing EEG and measured mean values of the modal frequency (MF), absolute spectral power (ASP), and relative (normalized) spectral power (RSP) of the delta, theta, alpha rhythms, and beta1 and beta2 subrhythms in 31 children with inborn visual dysfunctions (average intragroup visual acuity of about 0.2) and 49 children with normal vision (age, from 8 to 12 years). Background EEG activity in children with visual dysfunctions was characterized by lower ASPs of all EEG frequency ranges (maximally, of the alpha rhythm), a lower RSP of alpha oscillations against the background of a higher RSP of the delta range (and that of beta2 subrange in boys), and also by higher MFs of slow-wave activity and of beta oscillations (beta2 and beta1 subranges in girls and boys, respectively); the MF of alpha activity in most cortical regions was unchanged. The data obtained are probably indicative of increased activity of the caudal brainstem regions related to the existence of visual dysfunctions; this results in changes in the pattern of interaction between activating and deactivating cerebral systems. Possible compensatory mechanisms influencing integrative activity of the brain under conditions of visual dysfunctions are discussed.
      PubDate: 2014-04-01
       
  • Neuroprotective Effect of Vitamin E in a KainateInduced Rat Model of
           Temporal Lobe Epilepsy
    • Abstract: Temporal lobe epilepsy (TLE) is known as the most common form of epilepsy in adults and as the type most resistant to treatment. Neuroprotective treatments are considered a promising therapy for preventing and treating TLE. We investigated the possible neuroprotective effect of vitamin E in an intrahippocampal kainate model of TLE in rats. Kainate injection caused a higher incidence rate of seizures; vitamin E pretreatment significantly attenuated this index. Intrahippocampal kainate also led to elevation of the malondialdehyde (MDA) and nitrite/nitrate levels and lowered superoxide dismutase (SOD) activity, while vitamin E significantly restored MDA and SOD indices. In addition, intrahippocampal kainate induced a significant degeneration of neurons in the CA1, CA3, and hilar regions of the hippocampus; vitamin E considerably attenuated these changes. Timm staining data demonstrated mossy fiber sprouting (MFS) in the dentate gyrus of kainate-lesioned rats, and vitamin E significantly lowered the MFS intensity. Our data suggest that vitamin E pretreatment is capable of attenuating seizures and inhibiting hippocampal neuronal loss and MFS in the kainate-induced model of TLE. A part of the beneficial vitamin E effect is due to its potential to mitigate oxidative stress.
      PubDate: 2014-04-01
       
  • Diagnosing Autism Spectrum Disorders Based on EEG Analysis: a Survey
    • Abstract: Autism spectrum disorders (ASDs) are pervasive neurodevelopmental conditions characterized by impairments in reciprocal social interactions, communication skills, and stereotyped behavior. Since EEG recording and analysis is one of the fundamental tools in diagnosing and identifying disorders in neurophysiology, researchers strive to use the EEG signals for diagnosing individuals with ASD. We found that studies on ASD diagnosis using EEG techniques could be divided into two groups in which where analysis was based on either comparison techniques or pattern recognition techniques. In this paper, we try to explain these two sets of algorithms along with their applied methods and results. Lastly, evaluation measures of diagnosis algorithms are discussed.
      PubDate: 2014-04-01
       
  • EEG Activity during Viewing of Neutral and Emotionally Colored Pictures by
           Men and Women with Different Levels of Empathy
    • Abstract: We compared the characteristics of EEG in 14 men and 32 women, 18 to 21 years old, in the course of viewing neutral and emotionally (negatively, positively, and erotically) colored pictures from the International Affective Picture System (IAPS); women were tested during various phases of the ovulatory cycle. We demonstrated that changes in zonal characteristics of the main EEG rhythms related to perception of pictures of all types by men and women differed significantly from each other. In men, the EEG patterns upon the action of the above-mentioned stimuli were most similar to those observed in women during the follicular phase of the ovulatory cycle. In general, changes in EEG in the course of viewing pictures of all types were more significant in women as compared with men. For men, perception of erotically colored and negative pictures exerted greater activating effects. We found certain specificity of EEG patterns depending on the level of empathy of the tested subjects. High levels of empathy in men and women were associated with higher spectral powers of the beta and theta EEG rhythms, respectively. In women, the ability to show empathy was manifested in a different manner depending on the level of sex hormones; the presented visual stimuli could not evoke any emotional resonance in women during the follicular phase but began to evoke activation during the luteal phase.
      PubDate: 2014-04-01
       
  • Correlations between Indices of the Heart Rate Variability and Parameters
           of Ongoing EEG in Patients Suffering from Chronic Renal Pathology
    • Abstract: We examined correlations between indices of the heart rate variability (HRV) measured according to the cardiointervalogram (CIG) and parameters of the main rhythms of EEG recorded in a parallel mode in men suffering from chronic pyelonephritis (in the remission phase). We obtained a few equations of multiple regression that reflect interrelations between the absolute and relative (normalized) spectral and time-domain indices of CIG, on the one hand, and the amplitude/frequency and spectral parameters of EEG, on the other hand. According to values of the coefficient of canonical correlation with EEG parameters, CIG indices formed the following sequence: amplitude of the mode (R = 0.72), spectral power density (SPD) of the low-frequency (LF) component (R = 0.66), pNN50 (R = 0.65), mode (R = 0.64), SDNN (R = 0.63), SPD of the very low-frequency (VLF) component (R = 0.625), SPD of the high-frequency (HF) component (R = 0.55), RMSSD (R = 0.545), SPD of the ultralow-frequency (ULF) component (R = 0.455), and variation range (R = 0.38). Relative SPDs of the CIG components, similarly to LFnu, showed weaker correlations with EEG parameters (R = 0.535-0.42 and R = 0.42), while the ratio between the LF and HF powers demonstrated comparatively strong correlation (R = 0.56). The Baevsky stress index showed maximum correlation with EEG parameters (R = 0.80). According to the factor loadings, the absolute SPD of the α rhythm in leads O1 (r * = -0.51), Р3 (r* = -0.35) і С4 (r* = -0.29), that of the δ rhythm in leads Fp1 (r* = -0.41), O1 (r* = -0.40), T5 (r* = -0,39), F7 (r* = -0.39), and T6 (r* = -0.35), that of the β rhythm in locus О1 (r* = -0.34), relative SPD of the θ rhythm in loci F8 (r* = 0.38), Fр1 (r* = 0.32), and F4 (r* = 0.28), index of the θ rhythm (r* = 0.47), and also the modal β rhythm frequency (r * = 0.43) exert most significant influences on variability of the heart rhythm.
      PubDate: 2014-04-01
       
  • Gradient Trigger Mechanisms Related to Bistability Regimes in a Leech
           Heartbeat Model
    • Abstract: We studied bursting patterns underlying bifurcation phenomena and chaotic spiking in a computational leech heartbeat model. We observed the gradient physical properties of the ISI series and amplitude (shift of the membrane potential) when the parameter gleak was mildly changed and found different bistable areas. The resulting computation implies that (i) classification of the intensity of the input information is feasible in this regime, (ii) a neuron’s working level can be marked by its range in a typical bifurcation, and (iii) there are invisible triggers underlying subtle mechanisms in the model.
      PubDate: 2014-04-01
       
  • Redistribution of Cell Adhesion Proteins in the Brain and the
           Peculiarities of Behavioral Phenomena in Rats with Chronic Pancreatitis
    • Abstract: We demonstrated that, under conditions of the development of experimental pancreatitis accompanied by a decrease in locomotor and orientational-research activity of animals and also by the development of the stress state, concentrations of the soluble and membrane isoforms of neuronal cell adhesion molecule (NCAM) change in the cerebellum and thalamus.
      PubDate: 2014-04-01
       
  • Effects of Agents Influencing Serotonergic and Cannabinoid Systems on
           Memory in the Avoidance Test in Mice
    • Abstract: Adult male albino mice in a shuttle box system were used for examination of learning for avoidance behavior and its deactivation. We measured the step-through latency in the acquisition of the task (STLa) before injections of the drugs tested (fluoxetine and URB597, a serotonin reuptake inhibitor, SSRI, and an agent preventing decomposition of endocannabinoids, respectively) and the respective latency 24 h after injections of these agents (STLr); total time spent in the dark compartment (TDC) was also measured in these situations. In mice that received fluoxetine (5, 10, and 20 mg/kg), the STLr were longer than those in the control, and the difference was significant at 10 mg/kg. Injections of URB597 decreased the STLr, and at medium and high doses (0.3 and 1.0 mg/kg) significant differences were observed. All doses of fluoxetine led to significant decreases in the TDC values, while injections of URB597 increased this index (at 0.3 and 1.0 mg/kg, the shifts were significant). Combined injections of fluoxetine and URB597 (5 + 0.1, 10 + 0.3, and 20 + 1.0 mg/kg) increased the STLr values and decreased TDC values to levels comparable with those at isolated injections of fluoxetine in the respective doses. Thus, fluoxetine improves memory, while URB597 impaired it; fluoxetine is capable of nullifying the negative effects of URB597.
      PubDate: 2014-04-01
       
  • Changes in the Gene Expression of Inositol 1,4,5-Trisphosphate Receptors
           in Neurons of the Motor Cortex and Cerebellum of Rats with Experimental
           Hemiparkinsonism
    • Abstract: At present, researchers are greatly interested in intracellular calcium signaling and, in particular, in the mechanisms of its disturbance in different pathologies. Nonetheless, rather limited information on the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) in the development of neurodegenerative processes has been accumulated. The aim of our study was to clarify whether the IP3R1 expression in neurons under conditions of experimental Parkinson’s disease undergoes changes. In our experiments, we caused unilateral damage to dopaminergic neurons of the substantia nigra of rats using stereotaxic injections of 6-hydroxydopamine into the left ascending forebrain medial bundle (i.e., induced the state of experimental hemiparkinsonism). Using the technique of real-time polymerase chain reaction (RT PCR), we examined the level of expression of the itpr1 gene (that encodes type-1 IP3R subunits) in neurons of the cerebellum and motor cortex of intact rats and those with experimental hemiparkinsonism. In the latter animals, we observed higher levels of expression of gene itpr1 in neurons of both above-mentioned cerebral parts. In particular, the expression of this gene in the motor cortex exceeded that in the control rats more than two times, while in the cerebellum the excess was about 30 %. The higher expression of gene itpr1 in brain neurons can be a reason for abnormally intense release of Са2+ from the cellular stores during the development of neurodegenerative processes.
      PubDate: 2014-04-01
       
  • Effect of an Inhibitor of Sphingomyelinases, N-Acetylcysteine, on
           Cognitive Functions in Old Rats
    • Abstract: We examined conditioned reflex activity (an active avoidance reflex in a shuttle chamber) in 24-monthold rats against the background of the action of N-acetylcysteine (N-AcC) introduced perorally during 18 days. N-AcC improved the cognitive functions in old animals; rats better evaluated the experimental task, and the latencies of the reaction to unconditioned stimulation were shorter. This, in general, promoted training for the reflex as compared with that in control rats. Considering that N-AcC inhibits the activity of neutral sphingomyelinase (SMase) and normalizes the content of ceramides in the hippocampus and neocortex of 24-month-old animals, it can be supposed that suppression of hyperproduction of ceramides in the brain of rats is an important factor providing improvement of the cognitive functions in old rats; this effect is realized due to inhibition of activity of neutral SMase.
      PubDate: 2014-04-01
       
  • Organization of Activity of Hippocampal Pyramidal Neurons under
           Coactivation of Dendritic Glutamate- and GABA-Sensitive Receptors: a
           Simulation Study
    • Abstract: Using the model of a hippocampal pyramidal neuron with reconstructed dendritic arborization having active electrical properties of the membrane, we investigated the effects of tonic activation of dendritic receptor channels sensitive to glutamate and GABA on the patterns of impulse activity in the axon and on the corresponding electrical processes in the dendrites. Activation of these types of receptors was represented by introducing the uniformly distributed membrane conductivities G se and G si associated with the current reversal potentials of 0 and -60 mV, respectively. It was found that the dendritic membrane with voltage-gated ion channels typical of this-type neurons became, under the influence of suprathreshold activation of glutamate receptors, a source of self-oscillations of the membrane potential or persistent depolarization of the membrane with characteristic differences of the electrical processes in metrically asymmetrical parts of the dendritic arborization. At the neuronal output, regular periodic or stochastic sequences of action potentials (APs) were generated; their average repetition frequency f depended logarithmically on the G se. Coactivation of GABA receptors (G si > 0) led to an increase in the threshold and a decrease in the frequency of auto-oscillations in the dendrites (in this case, the autooscillations were renewed in the branches where persistent depolarization developed previously), as well as to a decrease in the mean frequency of AP firing, whereas the logarithmic dependence of f on the G se remained. An earlier undescribed effect was revealed; the transformation of firing patterns (irregular, stochastic, and regular, periodic) at certain ratios of the conductivities G se and G si occurred. It is assumed that the above-described features of the firing pattern formation in hippocampal pyramidal neurons are due to dynamical spatial coupling of the local auto-oscillatory processes. This coupling depends on the geometry and membrane conductivities of the dendrites, is modulated by coactivation of receptors of different types, and is determined by the parametric sensitivity of the dendritic transfer functions.
      PubDate: 2014-04-01
       
  • Cognitive Ability and Cardiovascular Control in Intellectually and
           Developmentally Disabled People
    • Abstract: Earlier, we examined the positive effects of hyperoxic air on the cognitive ability of intellectually and developmentally disabled people (IDDP). In this study, the correlation between cognitive performance in the visual matching task and heart rate (HR) was investigated under normal air conditions. Eighteen men (mean age 28.7 ± 5.0 year) and 22 women (mean age 35.5 ± 6.9 year) with an assessed disability level of 2.3 ± 0.6 participated. The experiment consisted of three phases, a total of 7 min, including the rest (3 min), control (2 min), and visual matching task (2 min) phases. The HR in the visual matching task phase increased, compared to that in the rest and control phases. The cognitive ability in the visual matching task correlated with the HR values; the response time showed a negative correlation with the HR, while the accuracy rate showed a positive correlation. Thus, adaptive changes in cardiovascular regulation probably related to cognitive efforts and emotional excitation is a noticeable factor influencing brain supply with oxygen in IDDP (similarly to those in healthy people). The result of this study agrees with the earlier obtained indications that hyperoxic air can positively affect the cognitive performance in IDDP.
      PubDate: 2014-04-01
       
  • Anticipatory Changes in the Soleus H Reflex in Humans Related to the
           Movements of the Contralateral Foot in Upright Stance
    • Abstract: In studies on healthy humans, we examined changes in the H reflex amplitude and the intensity of background EMG (bEMG) of the soleus muscle within the premotor period of voluntary movements of the contralateral foot. In the standing position with support on both lower limbs, we observed facilitation of the tested Н reflex and increase in the intensity of bEMG about 60 msec prior to the beginning of conditioned dorsiflexion of the foot. In the case of plantar flexion under analogous conditions, we observed anticipatory inhibition of the H reflex and suppression of bEMG. The pattern of these changes corresponded in general to reciprocal relations between the shin muscles. Opposite results were obtained in the case where the tested persons used an additional hand support. Under such conditions, they leaned only on the tested lower limb, while the conditioning one was not supporting. Plantar flexion of the contralateral foot caused, in this case, anticipatory facilitation of the tested H reflex. Therefore, premotor dynamics of the H reflex and of bEMG of the soleus muscle related to voluntary movements of the contralateral foot depend not only on the kind of movement but also on the body position, absence/ presence of additional support, and fulfillment/nonfulfillment of the support function by the lower limbs.
      PubDate: 2014-04-01
       
  • Dmitrii A. Moshkov
    • PubDate: 2014-04-01
       
  • Effects of Levetiracetam on Aggregation and Fusion of Membranes of
           Synaptic Vesicles in a Cell-Free Exocytosis Model
    • Abstract: We studied the effects of an antiepileptic drug, levetiracetam, on the processes of aggregation of synaptic vesicles (SVs) and their calcium-induced fusion with the target membranes in a cell-free model of neurosecretion. The size of SVs and their aggregates in the suspension was measured using laser-correlation spectroscopy. Fusion of the membrane structures was estimated quantitatively according to changes in the intensity of fluorescence self-quenching of the R18 probe (octadecylrhodamine B chloride). The action of levetiracetam resulted in intensification of clustering of SVs and decrease in the level of calcium-stimulated fusion of such vesicles both with the plasma membranes and with each other. Therefore, we obtained novel data on the effect of levetiracetam on regulation of the exocytosis process at stages of SV clustering and calcium-stimulated fusion of SVs with the target membranes.
      PubDate: 2014-04-01
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2014