The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform

Carolyn J Brown - One of the best experts on this subject based on the ideXlab platform.

Gennady Beryozkin - One of the best experts on this subject based on the ideXlab platform.

  • Vestibular nucleus projections to nucleus tractus solitarius and the dorsal motor nucleus of the vagus Nerve: Potential substrates for vestibulo-autonomic interactions
    Experimental Brain Research, 1994
    Co-Authors: Carey D. Balaban, Gennady Beryozkin
    Abstract:

    Autonomic effects of vestibular stimulation are important components of phenomena as diverse as acute vestibular dysfunction and motion sickness. How ever, the organization of neural circuits mediating these responses is poorly understood. This study presents evidence for direct vestibular nucleus projections to brain stem regions that mediate autonomic function. One group of albino rabbits received injections of Phaseolus vulgaris leucoagglutinin into the vestibular nuclei. The tracer was visualized immunocytochemically with standard techniques. Anterogradely labeled axons from the caudal medial vestibular nucleus (cMVN) and inferior vestibular nucleus (IVN) could be traced bilaterally to nucleus tractus solitarius (NTS). Fewer axons ended near the somata of neurons in the dorsal motor nucleus of the vagus Nerve (DMX). A second group of rabbits received pressure or iontophoretic injections of cholera toxin B-HRP or Fluoro-Gold into a region including NTS and DMX. Retrogradely labeled neurons were observed bilaterally in the caudal half of cMVN and ipsilaterally in IVN. The labeled somata were small and they tended to occupy the center of cMVN in transverse sections. These previously unreported vestibular nucleus projections to NTS and DMX are a Potential substrate for vestibular influences on autonomic function. In particular, they may contribute to both cardiovascular control during head movements (e.g., orthostatic reflexes) and autonomic manifestions of vestibular dysfunction, motion sickness and exposure to altered gravitational environments.

Amilton Antunes Barreira - One of the best experts on this subject based on the ideXlab platform.

  • Near Nerve Potential of sural Nerve in leprosy.
    Arquivos De Neuro-psiquiatria, 2004
    Co-Authors: Ana Paula M. Arruda, Wilson Marques, Norma Tiraboschi Foss, José Antonio Garbino, Marcos Virmond, Amilton Antunes Barreira
    Abstract:

    Leprosy neuropathy is characterized by initial involvement of the small Nerve fibers, later followed by involvement of the large fibers, when routine Nerve conduction studies become abnormal. To increase the diagnostic yield and precocity of these studies, we applied the near Nerve technique to the sural Nerve of 8 leprosy patients. Contrary to our expectations, the main component of the sural Nerve sensory action Potential was abnormal in all patients, but the minimum conduction velocity originating from small 3-6 mm fibers was normal or only mildly involved in three patients. Also, although Schwann cells are the first to be involved in leprosy, the results are suggestive of axonal degeneration instead of demyelination. To better understand the neurophysiology and physiology of leprosy and to increase the accuracy and precocity of the diagnosis, it will be necessary to investigate patients in the very early stages of the disease and to correlate these findings with the corresponding Nerve pathology.

  • Near-Nerve Potential in lepromatous leprosy.
    Muscle & Nerve, 2003
    Co-Authors: Wilson Marques, Norma Tiraboschi Foss, Ana Paula M. Arruda, Amilton Antunes Barreira
    Abstract:

    In leprosy, sensory action Potentials (SAPs) may be normal in spite of clinical sensory loss. This may result from the early involvement of small Nerve fibers, which have Potentials that are not detected in routine studies. To evaluate this possibility, we used a near-Nerve recording technique that records Potentials from Nerve fibers as small as 4–6 μm in diameter. We hypothesized that this technique might increase the sensitivity of Nerve conduction studies in detecting leprosy neuropathy. We found the technique to be useful for recording conduction abnormalities in recently diagnosed patients, including those with preserved sensation, suggesting that axonal loss may be the underlying mechanism. Contrary to our hypothesis, however, recording the late SAP components did not improve the sensitivity of Nerve conduction studies. We suggest that the late components having normal conduction velocities may be generated by either regenerating or remyelinating abnormal fibers, which have an electrophysiological behavior similar to that of normal 4–6-μm-diameter fibers. Muscle Nerve 28: 460–463, 2003

  • Normal median near Nerve Potential
    Brazilian Journal of Medical and Biological Research, 1997
    Co-Authors: Wilson Marques, Amilton Antunes Barreira
    Abstract:

    In routine studies of sensory Nerve conduction, only fibers e7 µm in diameter are analyzed. The late components which originate from thinner fibers are not detected. This explains why a normal sensory action Potential (SAP) may be recorded in patients with peripheral neuropathies and sensory loss. In the present study we investigated the late component of the median SAP with a near Nerve needle electrode technique in 14 normal volunteers (7 men and 7 women), aged 34.5 ± 14.8 years. The stimulus consisted of rectangular pulses of 0.2-ms duration at a frequency of 1 Hz with an intensity at least 6 times greater than the threshold value for the main component. Five hundred to 2000 sweep averagings were performed. The duration of analysis was 40 or 50 ms and the wave analysis frequency was 200 (-6 dB/oct) to 3000 Hz (-12 dB/oct). We used an apparatus with a two-channel amplifier system, 200 M W or more of entry impedance and a noise level of 0.7 µVrms or less. The main component mean amplitude, conduction velocity and latency and the late component mean amplitude, conduction velocity and latency were respectively (mean ± SD): 26.5 ± 5.42 µV, 56.8 ± 5.42 m/s, 3.01 ± 0.31 ms, 0.12 ± 0.04 µV, 16.4 ± 2.95 m/s and 10.6 ± 2.48 ms. More sophisticated equipment has an internal noise of 0.6 µVrms. These data demonstrate that the technique can now be employed to study thin fiber neuropathies, like in leprosy, using commercial electromyographs, even in non-academic practices

Sonia Pellissier - One of the best experts on this subject based on the ideXlab platform.

  • anti inflammatory properties of the vagus Nerve Potential therapeutic implications of vagus Nerve stimulation
    The Journal of Physiology, 2016
    Co-Authors: Bruno Bonaz, Valerie Sinniger, Sonia Pellissier
    Abstract:

    Brain and viscera interplay within the autonomic nervous system where the vagus Nerve (VN), containing approximately 80% afferent and 20% efferent fibres, plays multiple key roles in the homeostatic regulations of visceral functions. Recent data have suggested the anti-inflammatory role of the VN. This vagal function is mediated through several pathways, some of them still debated. The first one is the anti-inflammatory hypothalamic-pituitary-adrenal axis which is stimulated by vagal afferent fibres and leads to the release of cortisol by the adrenal glands. The second one, called the cholinergic anti-inflammatory pathway, is mediated through vagal efferent fibres that synapse onto enteric neurons which release acetylcholine (ACh) at the synaptic junction with macrophages. ACh binds to α-7-nicotinic ACh receptors of those macrophages to inhibit the release of tumour necrosis (TNF)α, a pro-inflammatory cytokine. The last pathway is the splenic sympathetic anti-inflammatory pathway, where the VN stimulates the splenic sympathetic Nerve. Norepinephrine (noradrenaline) released at the distal end of the splenic Nerve links to the β2 adrenergic receptor of splenic lymphocytes that release ACh. Finally, ACh inhibits the release of TNFα by spleen macrophages through α-7-nicotinic ACh receptors. Understanding of these pathways is interesting from a therapeutic point of view, since they could be targeted in various ways to stimulate anti-inflammatory regulation in TNFα-related diseases such as inflammatory bowel disease and rheumatoid arthritis. Among others, VN stimulation, either as an invasive or non-invasive procedure, is becoming increasingly frequent and several clinical trials are ongoing to evaluate the Potential effectiveness of this therapy to alleviate chronic inflammation.

Charles A Miller - One of the best experts on this subject based on the ideXlab platform.