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Sample records for auditory nerve fibers

  1. Response properties of the refractory auditory nerve fiber.

    Science.gov (United States)

    Miller, C A; Abbas, P J; Robinson, B K

    2001-09-01

    The refractory characteristics of auditory nerve fibers limit their ability to accurately encode temporal information. Therefore, they are relevant to the design of cochlear prostheses. It is also possible that the refractory property could be exploited by prosthetic devices to improve information transfer, as refractoriness may enhance the nerve's stochastic properties. Furthermore, refractory data are needed for the development of accurate computational models of auditory nerve fibers. We applied a two-pulse forward-masking paradigm to a feline model of the human auditory nerve to assess refractory properties of single fibers. Each fiber was driven to refractoriness by a single (masker) current pulse delivered intracochlearly. Properties of firing efficiency, latency, jitter, spike amplitude, and relative spread (a measure of dynamic range and stochasticity) were examined by exciting fibers with a second (probe) pulse and systematically varying the masker-probe interval (MPI). Responses to monophasic cathodic current pulses were analyzed. We estimated the mean absolute refractory period to be about 330 micros and the mean recovery time constant to be about 410 micros. A significant proportion of fibers (13 of 34) responded to the probe pulse with MPIs as short as 500 micros. Spike amplitude decreased with decreasing MPI, a finding relevant to the development of computational nerve-fiber models, interpretation of gross evoked potentials, and models of more central neural processing. A small mean decrement in spike jitter was noted at small MPI values. Some trends (such as spike latency-vs-MPI) varied across fibers, suggesting that sites of excitation varied across fibers. Relative spread was found to increase with decreasing MPI values, providing direct evidence that stochastic properties of fibers are altered under conditions of refractoriness.

  2. Evaluation of peripheral compression and auditory nerve fiber intensity coding using auditory steady-state responses

    DEFF Research Database (Denmark)

    Encina Llamas, Gerard; M. Harte, James; Epp, Bastian

    2015-01-01

    . Evaluation of these properties provides information about the health state of the system. It has been shown that a loss of outer hair cells leads to a reduction in peripheral compression. It has also recently been shown in animal studies that noise over-exposure, producing temporary threshold shifts, can....... The results indicate that the slope of the ASSR level growth function can be used to estimate peripheral compression simultaneously at four frequencies below 60 dB SPL, while the slope above 60 dB SPL may provide information about the integrity of intensity coding of low-SR fibers.......The compressive nonlinearity of the auditory system is assumed to be an epiphenomenon of a healthy cochlea and, particularly, of outer-hair cell function. Another ability of the healthy auditory system is to enable communication in acoustical environments with high-level background noises...

  3. Waveform efficiency analysis of auditory nerve fiber stimulation for cochlear implants

    International Nuclear Information System (INIS)

    Navaii, Mehdi Lotfi; Sadhedi, Hamed; Jalali, Mohsen

    2013-01-01

    Evaluation of the electrical stimulation efficiency of various stimulating waveforms is an important issue for efficient neural stimulator design. Concerning the implantable micro devices design, it is also necessary to consider the feasibility of hardware implementation of the desired waveforms. In this paper, the charge, power and energy efficiency of four waveforms (i.e. square, rising ramp, triangular and rising ramp-decaying exponential) in various durations have been simulated and evaluated based on the computational model of the auditory nerve fibers. Moreover, for a fair comparison of their feasibility, a fully integrated current generator circuit has been developed so that the desired stimulating waveforms can be generated. The simulation results show that stimulation with the square waveforms is a proper choice in short and intermediate durations while the rising ramp-decaying exponential or triangular waveforms can be employed for long durations.

  4. A phenomenological model of the electrically stimulated auditory nerve fiber: temporal and biphasic response properties

    Directory of Open Access Journals (Sweden)

    Colin eHorne

    2016-02-01

    Full Text Available We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs. The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability under both monophasic and cathodic-anodic biphasic stimulation, without changing the model’s parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions.Our work extends the stochastic leaky integrate and fire (SLIF neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model.

  5. Fast negative feedback enables mammalian auditory nerve fibers to encode a wide dynamic range of sound intensities.

    Directory of Open Access Journals (Sweden)

    Mark Ospeck

    Full Text Available Mammalian auditory nerve fibers (ANF are remarkable for being able to encode a 40 dB, or hundred fold, range of sound pressure levels into their firing rate. Most of the fibers are very sensitive and raise their quiescent spike rate by a small amount for a faint sound at auditory threshold. Then as the sound intensity is increased, they slowly increase their spike rate, with some fibers going up as high as ∼300 Hz. In this way mammals are able to combine sensitivity and wide dynamic range. They are also able to discern sounds embedded within background noise. ANF receive efferent feedback, which suggests that the fibers are readjusted according to the background noise in order to maximize the information content of their auditory spike trains. Inner hair cells activate currents in the unmyelinated distal dendrites of ANF where sound intensity is rate-coded into action potentials. We model this spike generator compartment as an attenuator that employs fast negative feedback. Input current induces rapid and proportional leak currents. This way ANF are able to have a linear frequency to input current (f-I curve that has a wide dynamic range. The ANF spike generator remains very sensitive to threshold currents, but efferent feedback is able to lower its gain in response to noise.

  6. Basic response characteristics of auditory nerve fibers in the grassfrog (Rana temporaria)

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Jørgensen, M B; Kanneworff, M

    1998-01-01

    -excitatory suppression (PS) of their spontaneous activity. The duration of PS increased with sound level, also in fibers showing a decrease in firing rate at high intensities. Most fibers showing one-tone suppression did not show PS at their best suppression frequencies. Strong suppression was observed also in very......Responses to free-field sound of 401 fibers from the VIIIth nerve of the grassfrog, Rana temporaria, are described. The spontaneous activities of the fibers ranged from 0 to 75 spikes/s, showing only weak correlation with frequency or sensitivity of the fibers. The highest spontaneous activities...... were approximately twice as high as reported previously for frogs. Best frequencies ranged from 100 to 1600 Hz and thresholds ranged from 21 to 80 dB SPL. The median dynamic range was 20 dB and the slopes of the rate-level curves ranged from 5 to 20 spikes/(s-dB). Most of the units showed post...

  7. Directionality of auditory nerve fiber responses to pure tone stimuli in the grassfrog, Rana temporaria. II. Spike timing

    DEFF Research Database (Denmark)

    Jørgensen, M B; Christensen-Dalsgaard, J

    1997-01-01

    We studied the directionality of spike timing in the responses of single auditory nerve fibers of the grass frog, Rana temporaria, to tone burst stimulation. Both the latency of the first spike after stimulus onset and the preferred firing phase during the stimulus were studied. In addition, the ...

  8. A Model of Electrically Stimulated Auditory Nerve Fiber Responses with Peripheral and Central Sites of Spike Generation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    2017-01-01

    . A single ANF is modeled as a network of two exponential integrateand-fire point-neuron models, referred to as peripheral and central axons of the ANF. The peripheral axon is excited by the cathodic charge, inhibited by the anodic charge, and exhibits longer spike latencies than the central axon......A computational model of cat auditory nerve fiber (ANF) responses to electrical stimulation is presented. The model assumes that (1) there exist at least two sites of spike generation along the ANF and (2) both an anodic (positive) and a cathodic (negative) charge in isolation can evoke a spike......; the central axon is excited by the anodic charge, inhibited by the cathodic charge, and exhibits shorter spike latencies than the peripheral axon. The model also includes subthreshold and suprathreshold adaptive feedback loops which continuously modify the membrane potential and can account for effects...

  9. Effects on auditory-nerve fibers of opening the otic capsule at the apex of the chinchilla cochlea

    Science.gov (United States)

    Recio-Spinoso, Alberto; Temchin, Andrei N.; Ruggero, Mario A.

    2015-12-01

    Vibration responses to clicks measured at the apex of chinchilla cochleae with open otic capsules have onsets much shorter than those of responses of auditory-nerve fibers (ANFs) corrected for synaptic and neural delays. Apical vibration responses to tones in open cochleae also differ in other respects from the responses to tones of ANFs with low characteristic frequency (CF) in normal chinchilla cochleae. To further specify the origin(s) of these differences, we recorded from chinchilla ANFs after delicately opening a small hole in the otic capsule overlying scala vestibuli in the cochlear apex. In those cochleae, the earliest ANF responses to clicks are often evoked by condensation (rather than rarefaction) clicks and responses to tones often exhibit level-dependent phase changes different from those in normal cochleae. These findings are largely consistent with, and seem to account for, apical vibration responses of cochleae with open otic capsules. An unexpected finding is that the tuning curves of ANFs with moderately high CF and normal CF thresholds often had hypersensitive tails.

  10. Adaptation, saturation, and physiological masking in single auditory-nerve fibers.

    Science.gov (United States)

    Smith, R L

    1979-01-01

    Results are reviewed concerning some effects, at a units's characteristic frequency, of a short-term conditioning stimulus on the responses to perstimulatory and poststimulatory test tones. A phenomenological equation is developed from the poststimulatory results and shown to be consistent with the perstimulatory results. According to the results and equation, the response to a test tone equals the unconditioned or unadapted response minus the decrement produced by adaptation to the conditioning tone. Furthermore, the decrement is proportional to the driven response to the conditioning tone and does not depend on sound intensity per se. The equation has a simple interpretation in terms of two processes in cascade--a static saturating nonlinearity followed by additive adaptation. Results are presented to show that this functional model is sufficient to account for the "physiological masking" produced by wide-band backgrounds. According to this interpretation, a sufficiently intense background produces saturation. Consequently, a superimposed test tone cause no change in response. In addition, when the onset of the background precedes the onset of the test tone, the total firing rate is reduced by adaptation. Evidence is reviewed concerning the possible correspondence between the variables in the model and intracellular events in the auditory periphery.

  11. One-tone suppression in the frog auditory nerve

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Jørgensen, M B

    1996-01-01

    Sixty-seven fibers of a sample of 401 in the auditory nerve of grassfrogs (Rana temporaria) showed one-tone suppression, i.e., their spontaneous activity was suppressed by tones. All fibers were afferents from the amphibian papilla with best frequencies between 100 and 400 Hz. Best suppression...

  12. Perceptual consequences of disrupted auditory nerve activity.

    Science.gov (United States)

    Zeng, Fan-Gang; Kong, Ying-Yee; Michalewski, Henry J; Starr, Arnold

    2005-06-01

    Perceptual consequences of disrupted auditory nerve activity were systematically studied in 21 subjects who had been clinically diagnosed with auditory neuropathy (AN), a recently defined disorder characterized by normal outer hair cell function but disrupted auditory nerve function. Neurological and electrophysical evidence suggests that disrupted auditory nerve activity is due to desynchronized or reduced neural activity or both. Psychophysical measures showed that the disrupted neural activity has minimal effects on intensity-related perception, such as loudness discrimination, pitch discrimination at high frequencies, and sound localization using interaural level differences. In contrast, the disrupted neural activity significantly impairs timing related perception, such as pitch discrimination at low frequencies, temporal integration, gap detection, temporal modulation detection, backward and forward masking, signal detection in noise, binaural beats, and sound localization using interaural time differences. These perceptual consequences are the opposite of what is typically observed in cochlear-impaired subjects who have impaired intensity perception but relatively normal temporal processing after taking their impaired intensity perception into account. These differences in perceptual consequences between auditory neuropathy and cochlear damage suggest the use of different neural codes in auditory perception: a suboptimal spike count code for intensity processing, a synchronized spike code for temporal processing, and a duplex code for frequency processing. We also proposed two underlying physiological models based on desynchronized and reduced discharge in the auditory nerve to successfully account for the observed neurological and behavioral data. These methods and measures cannot differentiate between these two AN models, but future studies using electric stimulation of the auditory nerve via a cochlear implant might. These results not only show the unique

  13. Organization of the auditory brainstem in a lizard, Gekko gecko. I. Auditory nerve, cochlear nuclei, and superior olivary nuclei

    DEFF Research Database (Denmark)

    Tang, Y. Z.; Christensen-Dalsgaard, J.; Carr, C. E.

    2012-01-01

    We used tract tracing to reveal the connections of the auditory brainstem in the Tokay gecko (Gekko gecko). The auditory nerve has two divisions, a rostroventrally directed projection of mid- to high best-frequency fibers to the nucleus angularis (NA) and a more dorsal and caudal projection of lo...... of auditory connections in lizards and archosaurs but also different processing of low- and high-frequency information in the brainstem. J. Comp. Neurol. 520:17841799, 2012. (C) 2011 Wiley Periodicals, Inc...

  14. Diffusion tensor imaging of the auditory nerve in patients with acquired single-sided deafness

    DEFF Research Database (Denmark)

    Vos, Sjoerd; Haakma, Wieke; Versnel, Huib

    2015-01-01

    following cochlear hair cell loss, and the amount of degeneration may considerably differ between the two ears, also in patients with bilateral deafness. A measure that reflects the nerve's condition would help to assess the best of both nerves and decide accordingly which ear should be implanted......A cochlear implant (CI) can restore hearing in patients with profound sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Therefore, the viability of the auditory nerve is vitally important in successful hearing recovery. However, the nerve typically degenerates...... single-sided sensorineural hearing loss. A specialized acquisition protocol was designed for a 3 T MRI scanner to image the small nerve bundle. The nerve was reconstructed using fiber tractography and DTI metrics - which reflect the nerve's microstructural properties - were computed per tract. Comparing...

  15. Ephaptic coupling of myelinated nerve fibers

    DEFF Research Database (Denmark)

    Binczak, S.; Eilbeck, J. C.; Scott, Alwyn C.

    2001-01-01

    Numerical predictions of a simple myelinated nerve fiber model are compared with theoretical results in the continuum and discrete limits, clarifying the nature of the conduction process on an isolated nerve axon. Since myelinated nerve fibers are often arranged in bundles, this model is used...

  16. Time course of dynamic range adaptation in the auditory nerve

    Science.gov (United States)

    Wang, Grace I.; Dean, Isabel; Delgutte, Bertrand

    2012-01-01

    Auditory adaptation to sound-level statistics occurs as early as in the auditory nerve (AN), the first stage of neural auditory processing. In addition to firing rate adaptation characterized by a rate decrement dependent on previous spike activity, AN fibers show dynamic range adaptation, which is characterized by a shift of the rate-level function or dynamic range toward the most frequently occurring levels in a dynamic stimulus, thereby improving the precision of coding of the most common sound levels (Wen B, Wang GI, Dean I, Delgutte B. J Neurosci 29: 13797–13808, 2009). We investigated the time course of dynamic range adaptation by recording from AN fibers with a stimulus in which the sound levels periodically switch from one nonuniform level distribution to another (Dean I, Robinson BL, Harper NS, McAlpine D. J Neurosci 28: 6430–6438, 2008). Dynamic range adaptation occurred rapidly, but its exact time course was difficult to determine directly from the data because of the concomitant firing rate adaptation. To characterize the time course of dynamic range adaptation without the confound of firing rate adaptation, we developed a phenomenological “dual adaptation” model that accounts for both forms of AN adaptation. When fitted to the data, the model predicts that dynamic range adaptation occurs as rapidly as firing rate adaptation, over 100–400 ms, and the time constants of the two forms of adaptation are correlated. These findings suggest that adaptive processing in the auditory periphery in response to changes in mean sound level occurs rapidly enough to have significant impact on the coding of natural sounds. PMID:22457465

  17. Sensation, mechanoreceptor, and nerve fiber function after nerve regeneration

    DEFF Research Database (Denmark)

    Krarup, Christian; Rosén, Birgitta; Boeckstyns, Michel

    2017-01-01

    Objective: Sensation is essential for recovery after peripheral nerve injury. However, the relationship between sensory modalities and function of regenerated fibers is uncertain. We have investigated the relationships between touch threshold, tactile gnosis, and mechanoreceptor and sensory fiber...... function after nerve regeneration. Methods: Twenty-one median or ulnar nerve lesions were repaired by a collagen nerve conduit or direct suture. Quantitative sensory hand function and sensory conduction studies by near-nerve technique, including tactile stimulation of mechanoreceptors, were followed for 2...... years, and results were compared to noninjured hands. Results: At both repair methods, touch thresholds at the finger tips recovered to 81 ± 3% and tactile gnosis only to 20 ± 4% (p nerve action potentials (SNAPs) remained dispersed and areas recovered to 23 ± 2...

  18. Organization of the auditory brainstem in a lizard, Gekko gecko. I. Auditory nerve, cochlear nuclei, and superior olivary nuclei.

    Science.gov (United States)

    Tang, Yezhong; Christensen-Dalsgaard, Jakob; Carr, Catherine E

    2012-06-01

    We used tract tracing to reveal the connections of the auditory brainstem in the Tokay gecko (Gekko gecko). The auditory nerve has two divisions, a rostroventrally directed projection of mid- to high best-frequency fibers to the nucleus angularis (NA) and a more dorsal and caudal projection of low to middle best-frequency fibers that bifurcate to project to both the NA and the nucleus magnocellularis (NM). The projection to NM formed large somatic terminals and bouton terminals. NM projected bilaterally to the second-order nucleus laminaris (NL), such that the ipsilateral projection innervated the dorsal NL neuropil, whereas the contralateral projection crossed the midline and innervated the ventral dendrites of NL neurons. Neurons in NL were generally bitufted, with dorsoventrally oriented dendrites. NL projected to the contralateral torus semicircularis and to the contralateral ventral superior olive (SOv). NA projected to ipsilateral dorsal superior olive (SOd), sent a major projection to the contralateral SOv, and projected to torus semicircularis. The SOd projected to the contralateral SOv, which projected back to the ipsilateral NM, NL, and NA. These results suggest homologous patterns of auditory connections in lizards and archosaurs but also different processing of low- and high-frequency information in the brainstem. Copyright © 2011 Wiley Periodicals, Inc.

  19. A model of auditory nerve responses to electrical stimulation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    Cochlear implants (CI) stimulate the auditory nerve (AN) with a train of symmetric biphasic current pulses comprising of a cathodic and an anodic phase. The cathodic phase is intended to depolarize the membrane of the neuron and to initiate an action potential (AP) and the anodic phase to neutral......Cochlear implants (CI) stimulate the auditory nerve (AN) with a train of symmetric biphasic current pulses comprising of a cathodic and an anodic phase. The cathodic phase is intended to depolarize the membrane of the neuron and to initiate an action potential (AP) and the anodic phase......-and-fire neuron with two partitions responding individually to anodic and cathodic stimulation. Membrane noise was parameterized based on reported relative spread of AN neurons. Firing efficiency curves and spike-latency distributions were simulated for monophasic and symmetric biphasic stimulation...

  20. Evaluation of dermal myelinated nerve fibers in diabetes mellitus

    Science.gov (United States)

    Peltier, Amanda C.; Myers, M. Iliza; Artibee, Kay J.; Hamilton, Audra D.; Yan, Qing; Guo, Jiasong; Shi, Yaping; Wang, Lily; Li, Jun

    2013-01-01

    Skin biopsies have primarily been used to study the non-myelinated nerve fibers of the epidermis in a variety of neuropathies. In the present study, we have expanded the skin biopsy technique to glabrous, non-hairy skin to evaluate myelinated nerve fibers in the most highly prevalent peripheral nerve disease, diabetic polyneuropathy (DPN). Twenty patients with DPN (Type I, n=9; Type II, n=11) and sixteen age-matched healthy controls (ages 29–73) underwent skin biopsy of the index finger, nerve conduction studies, and composite neuropathy scoring. In patients with DPN, we found a statistically significant reduction of both mechanoreceptive Meissner corpuscles (MC) and their afferent myelinated nerve fibers (p=0.01). This myelinated nerve fiber loss was correlated with the decreased amplitudes of sensory/motor responses in nerve conduction studies. This study supports the utilization of skin biopsy to quantitatively evaluate axonal loss of myelinated nerve fibers in patients with DPN. PMID:23781963

  1. Retinal nerve fiber layer thickness and neuropsychiatric manifestations in systemic lupus erythematosus.

    Science.gov (United States)

    Shulman, S; Shorer, R; Wollman, J; Dotan, G; Paran, D

    2017-11-01

    Background Cognitive impairment is frequent in systemic lupus erythematosus. Atrophy of the corpus callosum and hippocampus have been reported in patients with systemic lupus erythematosus, and diffusion tensor imaging studies have shown impaired white matter integrity, suggesting that white matter damage in systemic lupus erythematosus may underlie the cognitive impairment as well as other neuropsychiatric systemic lupus erythematosus manifestations. Retinal nerve fiber layer thickness, as assessed by optical coherence tomography, has been suggested as a biomarker for white matter damage in neurologic disorders such as multiple sclerosis, Alzheimer's disease and Parkinson's disease. Retinal nerve fiber layer thinning may occur early, even in patients with mild clinical symptoms. Aim The objective of this study was to assess the association of retinal nerve fiber layer thickness, as a biomarker of white matter damage in systemic lupus erythematosus patients, with neuropsychiatric systemic lupus erythematosus manifestations, including cognitive impairment. Methods Twenty-one consecutive patients with systemic lupus erythematosus underwent neuropsychological testing using a validated computerized battery of tests as well as the Rey-Auditory verbal learning test. All 21 patients, as well as 11 healthy, age matched controls, underwent optical coherence tomography testing to assess retinal nerve fiber layer thickness. Correlations between retinal nerve fiber layer thickness and results in eight cognitive domains assessed by the computerized battery of tests as well as the Rey-Auditory verbal learning test were assessed in patients with systemic lupus erythematosus, with and without neuropsychiatric systemic lupus erythematosus, and compared to retinal nerve fiber layer thickness in healthy controls. Results No statistically significant correlation was found between retinal nerve fiber layer thickness in patients with systemic lupus erythematosus as compared to healthy

  2. Modeling auditory-nerve responses to electrical stimulation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    2014-01-01

    μs, which is large enough to affect the temporal coding of sounds and hence, potentially, the communication abilities of the CI listener. In the present study, two recently proposed models of electric stimulation of the AN [1,2] were considered in terms of their efficacy to predict the spike timing...... for anodic and cathodic stimulation of the AN of cat [3]. The models’ responses to the electrical pulses of various shapes [4,5,6] were also analyzed. It was found that, while the models can account for the firing rates in response to various biphasic pulse shapes, they fail to correctly describe the timing......Cochlear implants (CI) directly stimulate the auditory nerve (AN), bypassing the mechano-electrical transduction in the inner ear. Trains of biphasic, charge balanced pulses (anodic and cathodic) are used as stimuli to avoid damage of the tissue. The pulses of either polarity are capable...

  3. Cell-type specific short-term plasticity at auditory nerve synapses controls feed-forward inhibition in the dorsal cochlear nucleus

    Directory of Open Access Journals (Sweden)

    Miloslav eSedlacek

    2014-07-01

    Full Text Available Feedforward inhibition represents a powerful mechanism by which control of the timing and fidelity of action potentials in local synaptic circuits of various brain regions is achieved. In the cochlear nucleus, the auditory nerve provides excitation to both principal neurons and inhibitory interneurons. Here, we investigated the synaptic circuit associated with fusiform cells (FCs, principal neurons of the dorsal cochlear nucleus (DCN that receive excitation from auditory nerve fibers and inhibition from tuberculoventral cells (TVCs on their basal dendrites in the deep layer of DCN. Despite the importance of these inputs in regulating fusiform cell firing behavior, the mechanisms determining the balance of excitation and feed-forward inhibition in this circuit are not well understood. Therefore, we examined the timing and plasticity of auditory nerve driven feed-forward inhibition (FFI onto FCs. We find that in some FCs, excitatory and inhibitory components of feed-forward inhibition had the same stimulation thresholds indicating they could be triggered by activation of the same fibers. In other FCs, excitation and inhibition exhibit different stimulus thresholds, suggesting FCs and TVCs might be activated by different sets of fibers. In addition we find that during repetitive activation, synapses formed by the auditory nerve onto TVCs and FCs exhibit distinct modes of short-term plasticity. Feed-forward inhibitory post-synaptic currents (IPSCs in FCs exhibit short-term depression because of prominent synaptic depression at the auditory nerve-TVC synapse. Depression of this feedforward inhibitory input causes a shift in the balance of fusiform cell synaptic input towards greater excitation and suggests that fusiform cell spike output will be enhanced by physiological patterns of auditory nerve activity.

  4. Cell-type specific short-term plasticity at auditory nerve synapses controls feed-forward inhibition in the dorsal cochlear nucleus.

    Science.gov (United States)

    Sedlacek, Miloslav; Brenowitz, Stephan D

    2014-01-01

    Feed-forward inhibition (FFI) represents a powerful mechanism by which control of the timing and fidelity of action potentials in local synaptic circuits of various brain regions is achieved. In the cochlear nucleus, the auditory nerve provides excitation to both principal neurons and inhibitory interneurons. Here, we investigated the synaptic circuit associated with fusiform cells (FCs), principal neurons of the dorsal cochlear nucleus (DCN) that receive excitation from auditory nerve fibers and inhibition from tuberculoventral cells (TVCs) on their basal dendrites in the deep layer of DCN. Despite the importance of these inputs in regulating fusiform cell firing behavior, the mechanisms determining the balance of excitation and FFI in this circuit are not well understood. Therefore, we examined the timing and plasticity of auditory nerve driven FFI onto FCs. We find that in some FCs, excitatory and inhibitory components of FFI had the same stimulation thresholds indicating they could be triggered by activation of the same fibers. In other FCs, excitation and inhibition exhibit different stimulus thresholds, suggesting FCs and TVCs might be activated by different sets of fibers. In addition, we find that during repetitive activation, synapses formed by the auditory nerve onto TVCs and FCs exhibit distinct modes of short-term plasticity. Feed-forward inhibitory post-synaptic currents (IPSCs) in FCs exhibit short-term depression because of prominent synaptic depression at the auditory nerve-TVC synapse. Depression of this feedforward inhibitory input causes a shift in the balance of fusiform cell synaptic input towards greater excitation and suggests that fusiform cell spike output will be enhanced by physiological patterns of auditory nerve activity.

  5. Diffusion tensor imaging of the auditory nerve in patients with long-term single-sided deafness

    NARCIS (Netherlands)

    Vos, Sjoerd; Haakma, Wieke; Versnel, Huib; Froeling, Martijn; Speleman, Lucienne; Dik, Pieter; Viergever, Max A.; Leemans, Alexander; Grolman, Wilko

    A cochlear implant (CI) can restore hearing in patients with profound sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Therefore, the viability of the auditory nerve is vitally important in successful hearing recovery. However, the nerve typically degenerates

  6. Serotonin Immunoreactive Cells and Nerve Fibers in the Mucosa of ...

    African Journals Online (AJOL)

    hydroxytryptamine) immunoreactivity in the pyloric mucosa of the rat stomach. The immunoreactive elements included the endocrine cells, mast cells and mucosal nerve fibers in the lamina propria. The immunopositive endocrine cells were oval in ...

  7. Tone and call responses of units in the auditory nerve and dorsal medullary nucleus of Xenopus laevis

    DEFF Research Database (Denmark)

    Elliott, Taffeta M.; Christensen-Dalsgaard, Jakob; Kelley, Darcy B.

    2007-01-01

    The clawed frog Xenopus laevis produces vocalizations consisting of distinct patterns of clicks. This study provides the first description of spontaneous, pure-tone and communication-signal evoked discharge properties of auditory nerve (n.VIII) fibers and dorsal medullary nucleus (DMN) cells...... in an obligatorily aquatic anuran. Responses of 297 n.VIII and 253 DMN units are analyzed for spontaneous rates (SR), frequency tuning, rate-intensity functions, and firing rate adaptation, with a view to how these basic characteristics shape responses to recorded call stimuli. Response properties generally resemble......Hz with approximately 500 Hz in 3 dB bandwidth. SRs range from 0 to 80 (n.VIII) and 0 to 73 spikes/s (DMN). Nerve and DMN units of all CFs follow click rates in natural calls,

  8. Towards Clinical Application of Neurotrophic Factors to the Auditory Nerve; Assessment of Safety and Efficacy by a Systematic Review of Neurotrophic Treatments in Humans

    NARCIS (Netherlands)

    Bezdjian, Aren; Kraaijenga, Véronique J C; Ramekers, Dyan; Versnel, Huib; Thomeer, Hans G X M; Klis, Sjaak F L; Grolman, Wilko

    2016-01-01

    Animal studies have evidenced protection of the auditory nerve by exogenous neurotrophic factors. In order to assess clinical applicability of neurotrophic treatment of the auditory nerve, the safety and efficacy of neurotrophic therapies in various human disorders were systematically reviewed.

  9. Nerve fibers and menstrual cycle in peritoneal endometriosis.

    Science.gov (United States)

    Wang, Guoyun; Tokushige, Natsuko; Fraser, Ian S

    2011-06-30

    There was no difference in the density of nerve fibers across the menstrual cycle in peritoneal endometriotic lesions. These findings may explain why patients with peritoneal endometriosis often have painful symptoms throughout the menstrual cycle. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  10. Spatial clustering analysis in neuroanatomy: Applications of different approaches to motor nerve fiber distribution

    NARCIS (Netherlands)

    Crunelli, V.; Prodanov, D.P.; Nagelkerke, Nico; Marani, Enrico

    2007-01-01

    Spatial organization of the nerve fibers in the peripheral nerves may be important for the studies of axonal regeneration, the degenerative nerve diseases and the construction of interfaces with peripheral nerves, such as nerve prostheses. Functional topography of motor axons related to the

  11. On the nature of the afferent fibers of oculomotor nerve.

    Science.gov (United States)

    Manni, E; Draicchio, F; Pettorossi, V E; Carobi, C; Grassi, S; Bortolami, R; Lucchi, M L

    1989-03-01

    The oculogyric nerves contain afferent fibers originating from the ophthalmic territory, the somata of which are located in the ipsilateral semilunar ganglion. These primary sensory neurons project to the Subnucleus Gelatinosus of the Nucleus Caudalis Trigemini, where they make presynaptic contact with the central endings of the primary trigeminal afferents running in the fifth cranial nerve. After complete section of the trigeminal root, the antidromic volleys elicited in the trunk of the third cranial nerve by stimulating SG of NCT consisted of two waves belonging to the A delta and C groups. The area of both components of the antidromic volleys decreased both after bradykinin and hystamine injection into the corresponding cutaneous region and after thermic stimulation of the ipsilateral trigeminal ophthalmic territory. The reduction of such potentials can be explained in terms of collision between the antidromic volleys and those elicited orthodromically by chemical and thermic stimulation. Also, capsaicin applied on the nerve induced an immediate increase, followed by a long lasting decrease, of orthodromic evoked response area. These findings bring further support to the nociceptive nature of the afferent fibers running into the oculomotor nerve.

  12. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

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    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang [Dept. of Radiology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)], e-mail: cjr.wzhch@vip.163.com; Mo, Lingyan [Dept. of Otorhinolaryngology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)

    2013-04-15

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was <1.5 mm in 36 ears (66.7%). The CNC diameter ranged between 1.5 and 2.0 mm in seven ears (13.0%) and was >2.0 mm in 11 ears (20.4%). The IAC diameter was <3.0 mm in 25 ears (46.3%) and >3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC.

  13. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

    International Nuclear Information System (INIS)

    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang; Mo, Lingyan

    2013-01-01

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was 2.0 mm in 11 ears (20.4%). The IAC diameter was 3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC

  14. Significance of bone changes at the meatus acusticus internus in tumours of the auditory nerve and in the 'empty' extended internal auditory meatus

    Energy Technology Data Exchange (ETDEWEB)

    Grehn, S.

    1988-06-01

    The unilateral extension of shortening of the internal auditory meatus is a very safe bony sign of the presence of a neurinoma of the auditory nerve. Differential diagnosis is necessary to exclude an 'empty' extended internal auditory meatus. On the other hand, 31% of the definitely established neurinomas do not show up in the plain tomogram. These facts prove that despite the presence or absence of allegedly definite bony changes at the internal auditory meatus further diagnostic measures are imperative, especially an air meatography in conjunction with high resolution computed tomography.

  15. Effect of diabetic retinopathy and panretinal photocoagulation on retinal nerve fiber layer and optic nerve appearance.

    Science.gov (United States)

    Lim, Michele C; Tanimoto, Suzana A; Furlani, Bruno A; Lum, Brent; Pinto, Luciano M; Eliason, David; Prata, Tiago S; Brandt, James D; Morse, Lawrence S; Park, Susanna S; Melo, Luiz A S

    2009-07-01

    To determine if panretinal photocoagulation (PRP) alters retinal nerve fiber layer (RNFL) thickness and optic nerve appearance. Patients with diabetes who did and did not undergo PRP and nondiabetic control subjects were enrolled in a prospective study. Participants underwent optical coherence tomography of the peripapillary retina and optic nerve. Stereoscopic optic nerve photographs were graded in a masked fashion. Ninety-four eyes of 48 healthy individuals, 89 eyes of 55 diabetic patients who did not undergo PRP, and 37 eyes of 24 subjects with diabetes who underwent PRP were included in this study. Eyes that had been treated with PRP had thinner peripapillary RNFL compared with the other groups; this was statistically significantly different in the inferior (P = .004) and nasal (P = .003) regions. Optic nerve cupping did not increase with severity of disease classification, but the proportion of optic nerves graded as suspicious for glaucoma or as having nonglaucomatous optic neuropathy did (P = .008). These grading categories were associated with thinner RNFL measurements. Diabetic eyes that have been treated with PRP have thinner RNFL than nondiabetic eyes. Optic nerves in eyes treated with PRP are more likely to be graded as abnormal, but their appearance is not necessarily glaucomatous and may be related to thinning of the RNFL.

  16. Changes in Properties of Auditory Nerve Synapses following Conductive Hearing Loss.

    Science.gov (United States)

    Zhuang, Xiaowen; Sun, Wei; Xu-Friedman, Matthew A

    2017-01-11

    Auditory activity plays an important role in the development of the auditory system. Decreased activity can result from conductive hearing loss (CHL) associated with otitis media, which may lead to long-term perceptual deficits. The effects of CHL have been mainly studied at later stages of the auditory pathway, but early stages remain less examined. However, changes in early stages could be important because they would affect how information about sounds is conveyed to higher-order areas for further processing and localization. We examined the effects of CHL at auditory nerve synapses onto bushy cells in the mouse anteroventral cochlear nucleus following occlusion of the ear canal. These synapses, called endbulbs of Held, normally show strong depression in voltage-clamp recordings in brain slices. After 1 week of CHL, endbulbs showed even greater depression, reflecting higher release probability. We observed no differences in quantal size between control and occluded mice. We confirmed these observations using mean-variance analysis and the integration method, which also revealed that the number of release sites decreased after occlusion. Consistent with this, synaptic puncta immunopositive for VGLUT1 decreased in area after occlusion. The level of depression and number of release sites both showed recovery after returning to normal conditions. Finally, bushy cells fired fewer action potentials in response to evoked synaptic activity after occlusion, likely because of increased depression and decreased input resistance. These effects appear to reflect a homeostatic, adaptive response of auditory nerve synapses to reduced activity. These effects may have important implications for perceptual changes following CHL. Normal hearing is important to everyday life, but abnormal auditory experience during development can lead to processing disorders. For example, otitis media reduces sound to the ear, which can cause long-lasting deficits in language skills and verbal

  17. Needle in the external auditory canal: an unusual complication of inferior alveolar nerve block.

    Science.gov (United States)

    Ribeiro, Leandro; Ramalho, Sara; Gerós, Sandra; Ferreira, Edite Coimbra; Faria e Almeida, António; Condé, Artur

    2014-06-01

    Inferior alveolar nerve block is used to anesthetize the ipsilateral mandible. The most commonly used technique is one in which the anesthetic is injected directly into the pterygomandibular space, by an intraoral approach. The fracture of the needle, although uncommon, can lead to potentially serious complications. The needle is usually found in the pterygomandibular space, although it can migrate and damage adjacent structures, with variable consequences. The authors report an unusual case of a fractured needle, migrating to the external auditory canal, as a result of an inferior alveolar nerve block. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Energy-optimal electrical excitation of nerve fibers.

    Science.gov (United States)

    Jezernik, Saso; Morari, Manfred

    2005-04-01

    We derive, based on an analytical nerve membrane model and optimal control theory of dynamical systems, an energy-optimal stimulation current waveform for electrical excitation of nerve fibers. Optimal stimulation waveforms for nonleaky and leaky membranes are calculated. The case with a leaky membrane is a realistic case. Finally, we compare the waveforms and energies necessary for excitation of a leaky membrane in the case where the stimulation waveform is a square-wave current pulse, and in the case of energy-optimal stimulation. The optimal stimulation waveform is an exponentially rising waveform and necessitates considerably less energy to excite the nerve than a square-wave pulse (especially true for larger pulse durations). The described theoretical results can lead to drastically increased battery lifetime and/or decreased energy transmission requirements for implanted biomedical systems.

  19. Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit

    Directory of Open Access Journals (Sweden)

    Pei-xun Zhang

    2015-01-01

    Full Text Available The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2-8 weeks, the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  20. Nerve canals at the fundus of the internal auditory canal on high-resolution temporal bone CT

    International Nuclear Information System (INIS)

    Ji, Yoon Ha; Youn, Eun Kyung; Kim, Seung Chul

    2001-01-01

    To identify and evaluate the normal anatomy of nerve canals in the fundus of the internal auditory canal which can be visualized on high-resolution temporal bone CT. We retrospectively reviewed high-resolution (1 mm thickness and interval contiguous scan) temporal bone CT images of 253 ears in 150 patients who had not suffered trauma or undergone surgery. Those with a history of uncomplicated inflammatory disease were included, but those with symptoms of vertigo, sensorineural hearing loss, or facial nerve palsy were excluded. Three radiologists determined the detectability and location of canals for the labyrinthine segment of the facial, superior vestibular and cochlear nerve, and the saccular branch and posterior ampullary nerve of the inferior vestibular nerve. Five bony canals in the fundus of the internal auditory canal were identified as nerve canals. Four canals were identified on axial CT images in 100% of cases; the so-called singular canal was identified in only 68%. On coronal CT images, canals for the labyrinthine segment of the facial and superior vestibular nerve were seen in 100% of cases, but those for the cochlear nerve, the saccular branch of the inferior vestibular nerve, and the singular canal were seen in 90.1%, 87.4% and 78% of cases, respectiveIy. In all detectable cases, the canal for the labyrinthine segment of the facial nerve was revealed as one which traversed anterolateralIy, from the anterosuperior portion of the fundus of the internal auditory canal. The canal for the cochlear nerve was located just below that for the labyrinthine segment of the facial nerve, while that canal for the superior vestibular nerve was seen at the posterior aspect of these two canals. The canal for the saccular branch of the inferior vestibular nerve was located just below the canal for the superior vestibular nerve, and that for the posterior ampullary nerve, the so-called singular canal, ran laterally or posteolateralIy from the posteroinferior aspect of

  1. Nerve canals at the fundus of the internal auditory canal on high-resolution temporal bone CT

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yoon Ha; Youn, Eun Kyung; Kim, Seung Chul [Sungkyunkwan Univ., School of Medicine, Seoul (Korea, Republic of)

    2001-12-01

    To identify and evaluate the normal anatomy of nerve canals in the fundus of the internal auditory canal which can be visualized on high-resolution temporal bone CT. We retrospectively reviewed high-resolution (1 mm thickness and interval contiguous scan) temporal bone CT images of 253 ears in 150 patients who had not suffered trauma or undergone surgery. Those with a history of uncomplicated inflammatory disease were included, but those with symptoms of vertigo, sensorineural hearing loss, or facial nerve palsy were excluded. Three radiologists determined the detectability and location of canals for the labyrinthine segment of the facial, superior vestibular and cochlear nerve, and the saccular branch and posterior ampullary nerve of the inferior vestibular nerve. Five bony canals in the fundus of the internal auditory canal were identified as nerve canals. Four canals were identified on axial CT images in 100% of cases; the so-called singular canal was identified in only 68%. On coronal CT images, canals for the labyrinthine segment of the facial and superior vestibular nerve were seen in 100% of cases, but those for the cochlear nerve, the saccular branch of the inferior vestibular nerve, and the singular canal were seen in 90.1%, 87.4% and 78% of cases, respectiveIy. In all detectable cases, the canal for the labyrinthine segment of the facial nerve was revealed as one which traversed anterolateralIy, from the anterosuperior portion of the fundus of the internal auditory canal. The canal for the cochlear nerve was located just below that for the labyrinthine segment of the facial nerve, while that canal for the superior vestibular nerve was seen at the posterior aspect of these two canals. The canal for the saccular branch of the inferior vestibular nerve was located just below the canal for the superior vestibular nerve, and that for the posterior ampullary nerve, the so-called singular canal, ran laterally or posteolateralIy from the posteroinferior aspect of

  2. Effect of Bluetooth headset and mobile phone electromagnetic fields on the human auditory nerve.

    Science.gov (United States)

    Mandalà, Marco; Colletti, Vittorio; Sacchetto, Luca; Manganotti, Paolo; Ramat, Stefano; Marcocci, Alessandro; Colletti, Liliana

    2014-01-01

    The possibility that long-term mobile phone use increases the incidence of astrocytoma, glioma and acoustic neuroma has been investigated in several studies. Recently, our group showed that direct exposure (in a surgical setting) to cell phone electromagnetic fields (EMFs) induces deterioration of auditory evoked cochlear nerve compound action potential (CNAP) in humans. To verify whether the use of Bluetooth devices reduces these effects, we conducted the present study with the same experimental protocol. Randomized trial. Twelve patients underwent retrosigmoid vestibular neurectomy to treat definite unilateral Ménière's disease while being monitored with acoustically evoked CNAPs to assess direct mobile phone exposure or alternatively the EMF effects of Bluetooth headsets. We found no short-term effects of Bluetooth EMFs on the auditory nervous structures, whereas direct mobile phone EMF exposure confirmed a significant decrease in CNAPs amplitude and an increase in latency in all subjects. The outcomes of the present study show that, contrary to the finding that the latency and amplitude of CNAPs are very sensitive to EMFs produced by the tested mobile phone, the EMFs produced by a common Bluetooth device do not induce any significant change in cochlear nerve activity. The conditions of exposure, therefore, differ from those of everyday life, in which various biological tissues may reduce the EMF affecting the cochlear nerve. Nevertheless, these novel findings may have important safety implications. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  3. External auditory canal cholesteatoma and keratosis obturans: the role of imaging in preventing facial nerve injury.

    Science.gov (United States)

    McCoul, Edward D; Hanson, Matthew B

    2011-12-01

    We conducted a retrospective study to compare the clinical characteristics of external auditory canal cholesteatoma (EACC) with those of a similar entity, keratosis obturans (KO). We also sought to identify those aspects of each disease that may lead to complications. We identified 6 patients in each group. Imaging studies were reviewed for evidence of bony erosion and the proximity of disease to vital structures. All 6 patients in the EACC group had their diagnosis confirmed by computed tomography (CT), which demonstrated widening of the bony external auditory canal; 4 of these patients had critical erosion of bone adjacent to the facial nerve. Of the 6 patients with KO, only 2 had undergone CT, and neither exhibited any significant bony erosion or expansion; 1 of them developed osteomyelitis of the temporal bone and adjacent temporomandibular joint. Another patient manifested KO as part of a dermatophytid reaction. The essential component of treatment in all cases of EACC was microscopic debridement of the ear canal. We conclude that EACC may produce significant erosion of bone with exposure of vital structures, including the facial nerve. Because of the clinical similarity of EACC to KO, misdiagnosis is possible. Temporal bone imaging should be obtained prior to attempts at debridement of suspected EACC. Increased awareness of these uncommon conditions is warranted to prompt appropriate investigation and prevent iatrogenic complications such as facial nerve injury.

  4. Diagnostic capability of optic nerve head rim width and retinal nerve fiber thickness in open-angle glaucoma.

    Science.gov (United States)

    Di Staso, Silvio; Agnifili, Luca; Di Staso, Federico; Climastone, Hilary; Ciancaglini, Marco; Scuderi, Gian Luca

    2018-03-01

    This study was performed to test the diagnostic capability of the minimum rim width compared to peripapillary retinal nerve fiber layer thickness in patients with glaucoma. A case control, observer masked study, was conducted. Minimum rim width and retinal nerve fiber layer thickness were assessed using the patient-specific axis traced between fovea-to-Bruch's membrane opening center axis. For both minimum rim width and retinal nerve fiber layer thickness, the regionalization in six sectors (nasal, superior-nasal, superior-temporal, temporal, inferior-temporal, and inferior-nasal) was analyzed. Eyes with at least one sector with value below the 5% or 1% normative limit of the optical coherence tomography normative database were classified as glaucomatous. The area under the receiver operator characteristic curve, the accuracy, sensitivity, specificity, and predictive positive and negative values were calculated for both minimum rim width and retinal nerve fiber layer thickness. A total of 118 eyes of 118 Caucasian subjects (80 eyes with open-angle glaucoma and 38 control eyes) were enrolled in the study. Accuracy, sensitivity, and specificity were 79.7%, 77.5%, and 84.2%, respectively, for minimum rim width and 84.7%, 82.5%, and 89.5% for retinal nerve fiber layer thickness. The positive predictive values were 0.91% and 0.94% for minimum rim width and retinal nerve fiber layer thickness, respectively, whereas the negative predictive values were 0.64% and 0.70%. The area under the receiver operator characteristic curve was 0.892 for minimum rim width and 0.938 for retinal nerve fiber layer thickness. Our results indicated that the sector analysis based on Bruch's membrane opening and fovea to disk alignment is able to detect glaucomatous defects, and that Bruch's membrane opening minimum rim width and retinal nerve fiber layer thickness showed equivalent diagnostic ability.

  5. Influence of oculomotor nerve afferents on central endings of primary trigeminal fibers.

    Science.gov (United States)

    Manni, E; Bortolami, R; Pettorossi, V E; Lucchi, M L; Callegari, E; Draicchio, F

    1987-12-01

    Painful fibers running in the third nerve and originating from the ophthalmic trigeminal area send their central projections at level of substantia gelatinosa of nucleus caudalis trigemini. The central endings of these fibers form axoaxonic synapses with trigeminal fibers entering the brain stem through the trigeminal root. The effect of electrical stimulation of the third nerve central stump on the central endings of trigeminal afferent fibers consists in an increased excitability, possibly resulting in a presynaptic inhibition. This inhibitory influence is due to both direct and indirect connections of the third nerve afferent fibers with the trigeminal ones.

  6. Auditory-nerve single-neuron thresholds to electrical stimulation from scala tympani electrodes.

    Science.gov (United States)

    Parkins, C W; Colombo, J

    1987-12-31

    Single auditory-nerve neuron thresholds were studied in sensory-deafened squirrel monkeys to determine the effects of electrical stimulus shape and frequency on single-neuron thresholds. Frequency was separated into its components, pulse width and pulse rate, which were analyzed separately. Square and sinusoidal pulse shapes were compared. There were no or questionably significant threshold differences in charge per phase between sinusoidal and square pulses of the same pulse width. There was a small (less than 0.5 dB) but significant threshold advantage for 200 microseconds/phase pulses delivered at low pulse rates (156 pps) compared to higher pulse rates (625 pps and 2500 pps). Pulse width was demonstrated to be the prime determinant of single-neuron threshold, resulting in strength-duration curves similar to other mammalian myelinated neurons, but with longer chronaxies. The most efficient electrical stimulus pulse width to use for cochlear implant stimulation was determined to be 100 microseconds/phase. This pulse width delivers the lowest charge/phase at threshold. The single-neuron strength-duration curves were compared to strength-duration curves of a computer model based on the specific anatomy of auditory-nerve neurons. The membrane capacitance and resulting chronaxie of the model can be varied by altering the length of the unmyelinated termination of the neuron, representing the unmyelinated portion of the neuron between the habenula perforata and the hair cell. This unmyelinated segment of the auditory-nerve neuron may be subject to aminoglycoside damage. Simulating a 10 micron unmyelinated termination for this model neuron produces a strength-duration curve that closely fits the single-neuron data obtained from aminoglycoside deafened animals. Both the model and the single-neuron strength-duration curves differ significantly from behavioral threshold data obtained from monkeys and humans with cochlear implants. This discrepancy can best be explained by

  7. Automated characterization of nerve fibers labeled fluorescently: determination of size, class and spatial distribution.

    Science.gov (United States)

    Prodanov, Dimiter; Feirabend, Hans K P

    2008-10-03

    Morphological classification of nerve fibers could help interpret the assessment of neural regeneration and the understanding of selectivity of nerve stimulation. Specific populations of myelinated nerve fibers can be investigated by retrograde tracing from a muscle followed by microscopic measurements of the labeled fibers at different anatomical levels. Gastrocnemius muscles of adult rats were injected with the retrograde tracer Fluoro-Gold. After a survival period of 3 days, cross-sections of spinal cords, ventral roots, sciatic, and tibial nerves were collected and imaged on a fluorescence microscope. Nerve fibers were classified using a variation-based criterion acting on the distribution of their equivalent diameters. The same criterion was used to classify the labeled axons using the size of the fluorescent marker. Measurements of the axons were paired to those of the entire fibers (axons+myelin sheaths) in order to establish the correspondence between so-established axonal and fiber classifications. It was found that nerve fibers in L6 ventral roots could be classified into four populations comprising two classes of Aalpha (denoted Aalpha1 and Aalpha2), Agamma, and an additional class of Agammaalpha fibers. Cut-off borders between Agamma and Agammaalpha fiber classes were estimated to be 5.00+/-0.09 microm (SEM); between Agammaalpha and Aalpha1 fiber classes to be 6.86+/-0.11 microm (SEM); and between Aalpha1 and Aalpha2 fiber classes to be 8.66+/-0.16 microm (SEM). Topographical maps of the nerve fibers that innervate the gastrocnemius muscles were constructed per fiber class for the spinal root L6. The major advantage of the presented approach consists of the combined indirect classification of nerve fiber types and the construction of topographical maps of so-identified fiber classes.

  8. Comparison of probabilistic and deterministic fiber tracking of cranial nerves.

    Science.gov (United States)

    Zolal, Amir; Sobottka, Stephan B; Podlesek, Dino; Linn, Jennifer; Rieger, Bernhard; Juratli, Tareq A; Schackert, Gabriele; Kitzler, Hagen H

    2017-09-01

    OBJECTIVE The depiction of cranial nerves (CNs) using diffusion tensor imaging (DTI) is of great interest in skull base tumor surgery and DTI used with deterministic tracking methods has been reported previously. However, there are still no good methods usable for the elimination of noise from the resulting depictions. The authors have hypothesized that probabilistic tracking could lead to more accurate results, because it more efficiently extracts information from the underlying data. Moreover, the authors have adapted a previously described technique for noise elimination using gradual threshold increases to probabilistic tracking. To evaluate the utility of this new approach, a comparison is provided with this work between the gradual threshold increase method in probabilistic and deterministic tracking of CNs. METHODS Both tracking methods were used to depict CNs II, III, V, and the VII+VIII bundle. Depiction of 240 CNs was attempted with each of the above methods in 30 healthy subjects, which were obtained from 2 public databases: the Kirby repository (KR) and Human Connectome Project (HCP). Elimination of erroneous fibers was attempted by gradually increasing the respective thresholds (fractional anisotropy [FA] and probabilistic index of connectivity [PICo]). The results were compared with predefined ground truth images based on corresponding anatomical scans. Two label overlap measures (false-positive error and Dice similarity coefficient) were used to evaluate the success of both methods in depicting the CN. Moreover, the differences between these parameters obtained from the KR and HCP (with higher angular resolution) databases were evaluated. Additionally, visualization of 10 CNs in 5 clinical cases was attempted with both methods and evaluated by comparing the depictions with intraoperative findings. RESULTS Maximum Dice similarity coefficients were significantly higher with probabilistic tracking (p cranial nerves. Probabilistic tracking with a gradual

  9. Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

    Science.gov (United States)

    Chiang, Jaclyn; Yapp, Michael; Ly, Angelica; Hennessy, Michael P; Kalloniatis, Michael; Zangerl, Barbara

    2018-03-01

    This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

  10. Retinal nerve fiber layer assessment by scanning laser polarimetry and standardized photography

    NARCIS (Netherlands)

    Niessen, A. G.; van den Berg, T. J.; Langerhorst, C. T.; Greve, E. L.

    1996-01-01

    To determine whether, in a clinical setting, scanning laser polarimetry and retinal nerve fiber layer photography provide equivalent information on the retinal nerve fiber layer. We prospectively studied 60 patients with glaucoma or ocular hypertension and 24 healthy subjects. With scanning laser

  11. Occurrence of substance P-like immunoreactive nerve fibers in Krause corpuscles of the dog's tongue.

    Science.gov (United States)

    Ichikawa, H; Nishikawa, S; Wakisaka, S; Matsuo, S; Takano, Y; Akai, M

    1988-01-01

    Substance P-like immunoreactive (SPLI) nerve fibers were demonstrated in the Krause corpuscles of the dog's tongue using the indirect immunofluorescence method and cholinesterase histochemistry. SPLI nerve fibers were often in contact with Krause end bulbs and occasionally entered them. From this result it was suggested that substance P might be involved in sensory mechanism of the Krause apparatus.

  12. A mathematical description of nerve fiber bundle trajectories and their variability in the human retina

    NARCIS (Netherlands)

    Jansonius, N. M.; Nevalainen, J.; Selig, B.; Zangwill, L. M.; Sample, P. A.; Budde, W. M.; Jonas, J. B.; Lagreze, W. A.; Airaksinen, P. J.; Vonthein, R.; Levin, L. A.; Paetzold, J.; Schiefer, U.

    2009-01-01

    We developed a mathematical model wherein retinal nerve fiber trajectories can be described and the corresponding inter-subject variability analyzed. The model was based on traced nerve fiber bundle trajectories extracted from 55 fundus photographs of 55 human subjects. The model resembled the

  13. Ultrastructural relationships between the receptor nerve fiber and surrounding lamellae in Krause end-bulbs.

    Science.gov (United States)

    Spassova, I

    1981-01-01

    The ultrastructural relationship between the receptor nerve fiber and the surrounding lamellae in Krause end-bulbs was discussed. Many sites of specialized junctions of symmetrical or asymmetrical type along the receptor nerve fiber and the surrounding lamellae were found. In addition, in close vicinity to them, spine-like digitations of the receptor nerve fiber, filled mainly with small clear vesicles, were observed. Mitochondrion-like cholinesterase-positive structures bulging in some cytoplasmic lamellae were also found. It is suggested that a functional link might exist between the specialized junctions, digitations and mitochrondrion-like structures in the transformation of external mechanical stimuli into nerve impulses.

  14. Effects of acoustic noise on the auditory nerve compound action potentials evoked by electric pulse trains.

    Science.gov (United States)

    Nourski, Kirill V; Abbas, Paul J; Miller, Charles A; Robinson, Barbara K; Jeng, Fuh-Cherng

    2005-04-01

    This study investigated the effects of acoustic noise on the auditory nerve compound action potentials in response to electric pulse trains. Subjects were adult guinea pigs, implanted with a minimally invasive electrode to preserve acoustic sensitivity. Electrically evoked compound action potentials (ECAP) were recorded from the auditory nerve trunk in response to electric pulse trains both during and after the presentation of acoustic white noise. Simultaneously presented acoustic noise produced a decrease in ECAP amplitude. The effect of the acoustic masker on the electric probe was greatest at the onset of the acoustic stimulus and it was followed by a partial recovery of the ECAP amplitude. Following cessation of the acoustic noise, ECAP amplitude recovered over a period of approximately 100-200 ms. The effects of the acoustic noise were more prominent at lower electric pulse rates (interpulse intervals of 3 ms and higher). At higher pulse rates, the ECAP adaptation to the electric pulse train alone was larger and the acoustic noise, when presented, produced little additional effect. The observed effects of noise on ECAP were the greatest at high electric stimulus levels and, for a particular electric stimulus level, at high acoustic noise levels.

  15. Retinal Nerve Fiber Layer Converges More Convexly on Normal Smaller Optic Nerve Head.

    Science.gov (United States)

    Jung, Kyoung In; Shin, Jeong Ah; Park, Hae-Young Lopilly; Park, Chan Kee

    2015-08-01

    To investigate retinal nerve fiber layer (RNFL) configuration in the optic nerve head (ONH) and peripapillary area according to disc size and to determine whether it explains cup discrepancy among eyes with different disc sizes. Horizontal and vertical RNFL curvature and mean thickness were measured using confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph) in 63 normal subjects grouped by disc size. Average and quadrant RNFL thickness, disc size, average cup-to-disc ratio (CDR), and convergence angle at the optic disc were also measured using Cirrus HD-optical coherence tomography. The relationships between disc size and RNFL curvature, thickness, angle at optic disc, and CDR were evaluated. RNFL curvature and convergence angle reflects convexity "on" and "into" the optic disc, respectively. CDR was smaller for small discs and was positively correlated with disc size (Poptic disc were positively correlated with disc size (POptic disc area was negatively correlated with mean RNFL thickness at the optic disc margin measured by HRT (P=0.002), but not in the peripapillary area by optical coherence tomography. Using imaging techniques, we demonstrated that the shape of the RNFLs converging "on" and entering "into" the optic disc was more convex for small optic discs compared with large discs. A low CDR for small discs could be mediated by these RNFL profiles at the ONH, which may guide the clinical evaluation of glaucomatous ONH damage.

  16. Determination of Nerve Fiber Diameter Distribution From Compound Action Potential: A Continuous Approach.

    Science.gov (United States)

    Un, M Kerem; Kaghazchi, Hamed

    2018-01-01

    When a signal is initiated in the nerve, it is transmitted along each nerve fiber via an action potential (called single fiber action potential (SFAP)) which travels with a velocity that is related with the diameter of the fiber. The additive superposition of SFAPs constitutes the compound action potential (CAP) of the nerve. The fiber diameter distribution (FDD) in the nerve can be computed from the CAP data by solving an inverse problem. This is usually achieved by dividing the fibers into a finite number of diameter groups and solve a corresponding linear system to optimize FDD. However, number of fibers in a nerve can be measured sometimes in thousands and it is possible to assume a continuous distribution for the fiber diameters which leads to a gradient optimization problem. In this paper, we have evaluated this continuous approach to the solution of the inverse problem. We have utilized an analytical function for SFAP and an assumed a polynomial form for FDD. The inverse problem involves the optimization of polynomial coefficients to obtain the best estimate for the FDD. We have observed that an eighth order polynomial for FDD can capture both unimodal and bimodal fiber distributions present in vivo, even in case of noisy CAP data. The assumed FDD distribution regularizes the ill-conditioned inverse problem and produces good results.

  17. Noise Stress Induces an Epidermal Growth Factor Receptor/Xeroderma Pigmentosum-A Response in the Auditory Nerve.

    Science.gov (United States)

    Guthrie, O'neil W

    2017-03-01

    In response to toxic stressors, cancer cells defend themselves by mobilizing one or more epidermal growth factor receptor (EGFR) cascades that employ xeroderma pigmentosum-A (XPA) to repair damaged genes. Recent experiments discovered that neurons within the auditory nerve exhibit basal levels of EGFR+XPA co-expression. This finding implied that auditory neurons in particular or neurons in general have the capacity to mobilize an EGFR+XPA defense. Therefore, the current study tested the hypothesis that noise stress would alter the expression pattern of EGFR/XPA within the auditory nerve. Design-based stereology was used to quantify the proportion of neurons that expressed EGFR, XPA, and EGFR+XPA with and without noise stress. The results revealed an intricate neuronal response that is suggestive of alterations to both co-expression and individual expression of EGFR and XPA. In both the apical and middle cochlear coils, the noise stress depleted EGFR+XPA expression. Furthermore, there was a reduction in the proportion of neurons that expressed XPA-alone in the middle coils. However, the noise stress caused a significant increase in the proportion of neurons that expressed EGFR-alone in the middle coils. The basal cochlear coils failed to mobilize a significant response to the noise stress. These results suggest that EGFR and XPA might be part of the molecular defense repertoire of the auditory nerve.

  18. Noise Stress Induces an Epidermal Growth Factor Receptor/Xeroderma Pigmentosum–A Response in the Auditory Nerve

    Science.gov (United States)

    Guthrie, O’neil W.

    2017-01-01

    In response to toxic stressors, cancer cells defend themselves by mobilizing one or more epidermal growth factor receptor (EGFR) cascades that employ xeroderma pigmentosum–A (XPA) to repair damaged genes. Recent experiments discovered that neurons within the auditory nerve exhibit basal levels of EGFR+XPA co-expression. This finding implied that auditory neurons in particular or neurons in general have the capacity to mobilize an EGFR+XPA defense. Therefore, the current study tested the hypothesis that noise stress would alter the expression pattern of EGFR/XPA within the auditory nerve. Design-based stereology was used to quantify the proportion of neurons that expressed EGFR, XPA, and EGFR+XPA with and without noise stress. The results revealed an intricate neuronal response that is suggestive of alterations to both co-expression and individual expression of EGFR and XPA. In both the apical and middle cochlear coils, the noise stress depleted EGFR+XPA expression. Furthermore, there was a reduction in the proportion of neurons that expressed XPA-alone in the middle coils. However, the noise stress caused a significant increase in the proportion of neurons that expressed EGFR-alone in the middle coils. The basal cochlear coils failed to mobilize a significant response to the noise stress. These results suggest that EGFR and XPA might be part of the molecular defense repertoire of the auditory nerve. PMID:28056182

  19. Human Lymphatic Mesenteric Vessels: Morphology and Possible Function of Aminergic and NPY-ergic Nerve Fibers.

    Science.gov (United States)

    D'Andrea, Vito; Panarese, Alessandra; Taurone, Samanta; Coppola, Luigi; Cavallotti, Carlo; Artico, Marco

    2015-09-01

    The lymphatic vessels have been studied in different organs from a morphological to a clinical point of view. Nevertheless, the knowledge of the catecholaminergic control of the lymphatic circulation is still incomplete. The aim of this work is to study the presence and distribution of the catecholaminergic and NPY-ergic nerve fibers in the whole wall of the human mesenteric lymphatic vessels in order to obtain knowledge about their morphology and functional significance. The following experimental procedures were performed: 1) drawing of tissue containing lymphatic vessels; 2) cutting of tissue; 3) staining of tissue; 4) staining of nerve fibers; 5) histofluorescence microscopy for the staining of catecholaminergic nerve fibers; 6) staining of neuropeptide Y like-immune reactivity; 7) biochemical assay of proteins; 8) measurement of noradrenaline; 9) quantitative analysis of images; 10) statistical analysis of data. Numerous nerve fibers run in the wall of lymphatic vessels. Many of them are catecholaminergic in nature. Some nerve fibers are NPY-positive. The biochemical results on noradrenaline amounts are in agreement with morphological results on catecholaminergic nerve fibers. Moreover, the morphometric results, obtained by the quantitative analysis of images and the subsequent statistical analysis of data, confirm all our morphological and biochemical data. The knowledge of the physiological or pathological mechanism regulating the functions of the lymphatic system is incomplete. Nevertheless the catecholaminergic nerve fibers of the human mesenteric lymphatic vessels come from the adrenergic periarterial plexuses of the mesenterial arterial bed. NPY-ergic nerve fibers may modulate the microcirculatory mesenterial bed in different pathological conditions.

  20. Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    Tan, Ou; Liu, Liang; Liu, Li; Huang, David

    2018-02-01

    To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

  1. Alterations of sympathetic nerve fibers in avascular necrosis of femoral head.

    Science.gov (United States)

    Li, Deqiang; Liu, Peilai; Zhang, Yuankai; Li, Ming

    2015-01-01

    Avascular necrosis of the femoral head (ANFH) was mainly due to alterations of bone vascularity. And noradrenaline (NA), as the neurotransmitter of the sympathetic nervous system (SNS), leads to the vasoconstriction by activating its α-Receptor. This study was to explore the nerve fiber density of the femoral head in the rabbit model of ANFH. Twenty New Zealand white rabbits were used in this study. The rabbit model of ANFH was established by the injection of methylprednisolone acetate. The nerve fiber density and distribution in the femoral head was determined using an Olympus BH2 microscope. Significant fewer sympathetic nerve fibers was found in the ANFH intertrochanteric bone samples (P = 0.036) with osteonecrosis. The number of sympathetic nerve fibers was compared between the two groups. And less sympathetic nerve fibers were found in later stage ANFH samples in comparison with those of early stages. ANFH might be preceded by an inflammatory reaction, and an inflammatory response might lead to arthritic changes in tissue samples, which in turn reduces the number of sympathetic nerve fibers.

  2. Age, ocular magnification, and circumpapillary retinal nerve fiber layer thickness

    Science.gov (United States)

    Wang, Mengyu; Elze, Tobias; Li, Dian; Baniasadi, Neda; Wirkner, Kerstin; Kirsten, Toralf; Thiery, Joachim; Loeffler, Markus; Engel, Christoph; Rauscher, Franziska G.

    2017-12-01

    Optical coherence tomography (OCT) manufacturers graphically present circumpapillary retinal nerve fiber layer thickness (cpRNFLT) together with normative limits to support clinicians in diagnosing ophthalmic diseases. The impact of age on cpRNFLT is typically implemented by linear models. cpRNFLT is strongly location-specific, whereas previously published norms are typically restricted to coarse sectors and based on small populations. Furthermore, OCT devices neglect impacts of lens or eye size on the diameter of the cpRNFLT scan circle so that the diameter substantially varies over different eyes. We investigate the impact of age and scan diameter reported by Spectralis spectral-domain OCT on cpRNFLT in 5646 subjects with healthy eyes. We provide cpRNFLT by age and diameter at 768 angular locations. Age/diameter were significantly related to cpRNFLT on 89%/92% of the circle, respectively (pointwise linear regression), and to shifts in cpRNFLT peak locations. For subjects from age 42.1 onward but not below, increasing age significantly decreased scan diameter (r=-0.28, p<0.001), which suggests that pathological cpRNFLT thinning over time may be underestimated in elderly compared to younger subjects, as scan diameter decrease correlated with cpRNFLT increase. Our detailed numerical results may help to generate various correction models to improve diagnosing and monitoring optic neuropathies.

  3. Selective Fiber Degeneration in the Peripheral Nerve of a Patient With Severe Complex Regional Pain Syndrome

    Directory of Open Access Journals (Sweden)

    Adrien Yvon

    2018-04-01

    Full Text Available Aims: Complex regional pain syndrome (CRPS is characterized by chronic debilitating pain disproportional to the inciting event and accompanied by motor, sensory, and autonomic disturbances. The pathophysiology of CRPS remains elusive. An exceptional case of severe CRPS leading to forearm amputation provided the opportunity to examine nerve histopathological features of the peripheral nerves.Methods: A 35-year-old female developed CRPS secondary to low voltage electrical injury. The CRPS was refractory to medical therapy and led to functional loss of the forelimb, repeated cutaneous wound infections leading to hospitalization. Specifically, the patient had exhausted a targeted conservative pain management programme prior to forearm amputation. Radial, median, and ulnar nerve specimens were obtained from the amputated limb and analyzed by light and transmission electron microscopy (TEM.Results: All samples showed features of selective myelinated nerve fiber degeneration (47–58% of fibers on electron microscopy. Degenerating myelinated fibers were significantly larger than healthy fibers (p < 0.05, and corresponded to the larger Aα fibers (motor/proprioception whilst smaller Aδ (pain/temperature fibers were spared. Groups of small unmyelinated C fibers (Remak bundles also showed evidence of degeneration in all samples.Conclusions: We are the first to show large fiber degeneration in CRPS using TEM. Degeneration of Aα fibers may lead to an imbalance in nerve signaling, inappropriately triggering the smaller healthy Aδ fibers, which transmit pain and temperature. These findings suggest peripheral nerve degeneration may play a key role in CRPS. Improved knowledge of pathogenesis will help develop more targeted treatments.

  4. Neurophysiological assessment of auditory, peripheral nerve, somatosensory, and visual system function after developmental exposure to gasoline, E15, and E85 vapors.

    Data.gov (United States)

    U.S. Environmental Protection Agency — Visual, auditory, somatosensory, and peripheral nerve evoked responses. This dataset is associated with the following publication: Herr , D., D. Freeborn , L. Degn ,...

  5. NON-INVASIVE EVALUATION OF NERVE CONDUCTION IN SMALL DIAMETER FIBERS IN THE RAT

    OpenAIRE

    Zotova, Elena G.; Arezzo, Joseph C.

    2013-01-01

    A novel non-invasive technique was applied to measure velocity within slow conducting axons in the distal extreme of the sciatic nerve (i.e., digital nerve) in a rat model. The technique is based on the extraction of rectified multiple unit activity (MUA) from in vivo whole nerve compound responses. This method reliably identifies compound action potentials in thinly myelinated fibers conducting at a range of 9-18 m/s (Aδ axons), as well as in a subgroup of unmylinated C fibers conducting at ...

  6. Noninvasive Evaluation of Nerve Conduction in Small Diameter Fibers in the Rat

    OpenAIRE

    Elena G. Zotova; Joseph C. Arezzo

    2013-01-01

    A novel noninvasive technique was applied to measure velocity within slow conducting axons in the distal extreme of the sciatic nerve (i.e., digital nerve) in a rat model. The technique is based on the extraction of rectified multiple unit activity (MUA) from in vivo whole nerve compound responses. This method reliably identifies compound action potentials in thinly myelinated fibers conducting at a range of 9–18 m/s ( axons), as well as in a subgroup of unmyelinated C fibers conducting at ap...

  7. The role of the renal afferent and efferent nerve fibers in heart failure

    Science.gov (United States)

    Booth, Lindsea C.; May, Clive N.; Yao, Song T.

    2015-01-01

    Renal nerves contain afferent, sensory and efferent, sympathetic nerve fibers. In heart failure (HF) there is an increase in renal sympathetic nerve activity (RSNA), which can lead to renal vasoconstriction, increased renin release and sodium retention. These changes are thought to contribute to renal dysfunction, which is predictive of poor outcome in patients with HF. In contrast, the role of the renal afferent nerves remains largely unexplored in HF. This is somewhat surprising as there are multiple triggers in HF that have the potential to increase afferent nerve activity, including increased venous pressure and reduced kidney perfusion. Some of the few studies investigating renal afferents in HF have suggested that at least the sympatho-inhibitory reno-renal reflex is blunted. In experimentally induced HF, renal denervation, both surgical and catheter-based, has been associated with some improvements in renal and cardiac function. It remains unknown whether the effects are due to removal of the efferent renal nerve fibers or afferent renal nerve fibers, or a combination of both. Here, we review the effects of HF on renal efferent and afferent nerve function and critically assess the latest evidence supporting renal denervation as a potential treatment in HF. PMID:26483699

  8. Neura, nerves, nerve fibers, neurofibrils, microtubules: multidimensional routes of pain, pleasure, and voluntary action in images across the ages.

    Science.gov (United States)

    Frixione, Eugenio

    2013-01-01

    Available records indicate that the human body has always been conceived, in different periods and cultures, as spanned by multiple channels for internal communication and coherent functioning as a unit-"meridians" in treatises of Chinese medicine, metu in Egyptian papyri, srotas in Ayurvedic Indian texts, and neura in the Western scientific heritage from ancient Greece. Unfortunately, the earliest extant figurative depictions of such pathways of general control, complementary to the blood vessels, are late medieval copies of old crude sketches that attempted to show the main anatomico-physiological systems. The scarcity of adequate illustrations was more than compensated in the Renaissance, when the efforts of both artists and anatomists for the first time produced basically correct renditions of the human nervous system and many other bodily structures. As attention was next focused on microscopic structure as a requisite to understand physiological mechanisms, during the Enlightenment the nerves were revealed to consist of numerous thin tubes or fibers aligned in parallel. Improved microscopy techniques in the nineteenth century led to discovering and delineating still finer fibrils coursing along the cores of the nerve fibers themselves. Electron microscopy, developed throughout the twentieth century, recognized some of these fibrils within nerve fibers as being also tubular. All the progressive stages in understanding nerve construction, at increasingly more detailed scales, have been accompanied by technological advances and by debate about the structure and function relationship. And every step has been a source of amazing imagery. © 2013 Elsevier B.V. All rights reserved.

  9. Alpha-synuclein in cutaneous small nerve fibers

    Directory of Open Access Journals (Sweden)

    Siepmann T

    2016-10-01

    Full Text Available Timo Siepmann,1 Ben Min-Woo Illigens,2 Kristian Barlinn1 1Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; 2Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA Abstract: Despite progression in the development of pharmacological therapy, treatment of alpha synucleinopathies, such as Parkinson’s disease (PD and some atypical parkinsonism syndromes, is still challenging. To date, our knowledge of the mechanisms whereby the pathological form of alpha-synuclein causes structural and functional damage to the nervous system is limited and, consequently, there is a lack of specific diagnostic tools to evaluate pathology in these patients and differentiate PD from other neurodegenerative proteinopathies. Recent studies indicated that alpha-synuclein deposition in cutaneous small nerve fibers assessed by skin biopsies might be a valid disease marker of PD and facilitate early differentiation of PD from atypical parkinsonism syndromes. This observation is relevant since early diagnosis may enable timely treatment and improve quality of life. However, challenges include the necessity of standardizing immunohistochemical analysis techniques and the identification of potential distinct patterns of intraneural alpha-synuclein deposition among synucleinopathies. In this perspective, we explore the scientific and clinical opportunities arising from alpha-synuclein assessment using skin biopsies. These include elucidation of the peripheral nervous system pathology of PD and other synucleinopathies, identification of novel targets to study response to neuroprotective treatment, and improvement of clinical management. Furthermore, we discuss future challenges in exploring the diagnostic value of skin biopsy assessment for alpha-synuclein deposition and implementing the technique in clinical practice. Keywords: Parkinson’s disease, diagnosis, skin

  10. Relationship Between Optic Nerve Appearance and Retinal Nerve Fiber Layer Thickness as Explored with Spectral Domain Optical Coherence Tomography

    Science.gov (United States)

    Aleman, Tomas S.; Huang, Jiayan; Garrity, Sean T.; Carter, Stuart B.; Aleman, Wendy D.; Ying, Gui-shuang; Tamhankar, Madhura A.

    2014-01-01

    Purpose To study the relationship between the appearance of the optic nerve and the retinal nerve fiber layer (RNFL) thickness determined by spectral domain optical coherence tomography (OCT). Methods Records from patients with spectral domain-OCT imaging in a neuro-ophthalmology practice were reviewed. Eyes with glaucoma/glaucoma suspicion, macular/optic nerve edema, pseudophakia, and with refractive errors > 6D were excluded. Optic nerve appearance by slit lamp biomicroscopy was related to the RNFL thickness by spectral domain-OCT and to visual field results. Results Ninety-one patients (176 eyes; mean age: 49 ± 15 years) were included. Eighty-three eyes (47%) showed optic nerve pallor; 89 eyes (50.6%) showed RNFL thinning (sectoral or average peripapillary). Average peripapillary RNFL thickness in eyes with pallor (mean ± SD = 76 ± 17 μm) was thinner compared to eyes without pallor (91 ± 14 μm, P < 0.001). Optic nerve pallor predicted RNFL thinning with a sensitivity of 69% and a specificity of 75%. Optic nerve appearance predicted RNFL thinning (with a sensitivity and specificity of 81%) when RNFL had thinned by ∼ 40%. Most patients with pallor had RNFL thinning with (66%) or without (25%) visual field loss; the remainder had normal RNFL and fields (5%) or with visual field abnormalities (4%). Conclusions Optic nerve pallor as a predictor of RNFL thinning showed fair sensitivity and specificity, although it is optimally sensitive/specific only when substantial RNFL loss has occurred. Translational Relevance Finding an acceptable relationship between the optic nerve appearance by ophthalmoscopy and spectral domain-OCT RNFL measures will help the clinician's interpretation of the information provided by this technology, which is gaining momentum in neuro-ophthalmic research. PMID:25374773

  11. Cornea nerve fiber quantification and construction of phenotypes in patients with fibromyalgia.

    Science.gov (United States)

    Oudejans, Linda; He, Xuan; Niesters, Marieke; Dahan, Albert; Brines, Michael; van Velzen, Monique

    2016-03-23

    Cornea confocal microscopy (CCM) is a novel non-invasive method to detect small nerve fiber pathology. CCM generally correlates with outcomes of skin biopsies in patients with small fiber pathology. The aim of this study was to quantify the morphology of small nerve fibers of the cornea of patients with fibromyalgia in terms of density, length and branching and further phenotype these patients using standardized quantitative sensory testing (QST). Small fiber pathology was detected in the cornea of 51% of patients: nerve fiber length was significantly decreased in 44% of patients compared to age- and sex-matched reference values; nerve fiber density and branching were significantly decreased in 10% and 28% of patients. The combination of the CCM parameters and sensory tests for central sensitization, (cold pain threshold, mechanical pain threshold, mechanical pain sensitivity, allodynia and/or windup), yielded four phenotypes of fibromyalgia patients in a subgroup analysis: one group with normal cornea morphology without and with signs of central sensitization, and a group with abnormal cornea morphology parameters without and with signs of central sensitization. In conclusion, half of the tested fibromyalgia population demonstrates signs of small fiber pathology as measured by CCM. The four distinct phenotypes suggest possible differences in disease mechanisms and may require different treatment approaches.

  12. High-resolution imaging of retinal nerve fiber bundles in glaucoma using adaptive optics scanning laser ophthalmoscopy.

    Science.gov (United States)

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Ueda-Arakawa, Naoko; Yoshida, Sachiko; Akagi, Tadamichi; Ikeda, Hanako Ohashi; Nonaka, Atsushi; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2013-05-01

    To detect pathologic changes in retinal nerve fiber bundles in glaucomatous eyes seen on images obtained by adaptive optics (AO) scanning laser ophthalmoscopy (AO SLO). Prospective cross-sectional study. Twenty-eight eyes of 28 patients with open-angle glaucoma and 21 normal eyes of 21 volunteer subjects underwent a full ophthalmologic examination, visual field testing using a Humphrey Field Analyzer, fundus photography, red-free SLO imaging, spectral-domain optical coherence tomography, and imaging with an original prototype AO SLO system. The AO SLO images showed many hyperreflective bundles suggesting nerve fiber bundles. In glaucomatous eyes, the nerve fiber bundles were narrower than in normal eyes, and the nerve fiber layer thickness was correlated with the nerve fiber bundle widths on AO SLO (P fiber layer defect area on fundus photography, the nerve fiber bundles on AO SLO were narrower compared with those in normal eyes (P optic disc, the nerve fiber bundle width was significantly lower, even in areas without nerve fiber layer defect, in eyes with glaucomatous eyes compared with normal eyes (P = .026). The mean deviations of each cluster in visual field testing were correlated with the corresponding nerve fiber bundle widths (P = .017). AO SLO images showed reduced nerve fiber bundle widths both in clinically normal and abnormal areas of glaucomatous eyes, and these abnormalities were associated with visual field defects, suggesting that AO SLO may be useful for detecting early nerve fiber bundle abnormalities associated with loss of visual function. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Morphometric analysis of the diameter and g-ratio of the myelinated nerve fibers of the human sciatic nerve during the aging process.

    Science.gov (United States)

    Ugrenović, Sladjana; Jovanović, Ivan; Vasović, Ljiljana; Kundalić, Braca; Čukuranović, Rade; Stefanović, Vladisav

    2016-06-01

    Myelinated nerve fibers suffer from different degrees of atrophy with age. The success of subsequent regeneration varies. The aim of this research was to analyze myelinated fibers of the human sciatic nerve during the aging process. Morphometric analysis was performed on 17 cases with an age range from 9 to 93 years. The outer and inner diameter of 100 randomly selected nerve fibers was measured in each of the cases evaluated, and the g-ratio (axonal diameter/outer diameter of the whole nerve fiber) of each was calculated. Scatter plots of the diameters and g-ratios of the analyzed fibers were then analyzed. Nerve fibers of each case were classified into three groups according to the g-ratio values: group I (g-ratio lower than 0.6), group II (g-ratio from 0.6 to 0.7) and group III (g-ratio higher than 0.7). Afterwards, nerve fibers of group II were further classified into small and large subgroups. The percentages of each group of nerve fibers were computed for each case and these values were used for correlational and bivariate linear regression analysis. The percentage of myelinated nerve fibers with large diameter and optimal g-ratio of the sciatic nerve declines significantly with age. This is accompanied by a simultaneous significant increase in the percentage of small myelinated fibers with g-ratio values close to 1 that occupy the upper left quadrant of the scatter plot. It can be concluded that aging of the sciatic nerve is associated with significant atrophy of large myelinated fibers. Additionally, a significant increase in regenerated nerve fibers with thinner myelin sheath is observed with age, which, together with the large myelinated fiber atrophy, might be the cause of the age-related decline in conduction velocity. A better understanding of the changes in aging peripheral nerves might improve interpretation of their pathological changes, as well as comprehension of their regeneration in individuals of different age.

  14. Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning.

    Science.gov (United States)

    Garcia-Martin, Elena; Garcia-Campayo, Javier; Puebla-Guedea, Marta; Ascaso, Francisco J; Roca, Miguel; Gutierrez-Ruiz, Fernando; Vilades, Elisa; Polo, Vicente; Larrosa, Jose M; Pablo, Luis E; Satue, Maria

    2016-01-01

    To investigate whether fibromyalgia induces axonal damage in the optic nerve that can be detected using optical coherence tomography (OCT), as the retinal nerve fiber layer (RNFL) is atrophied in patients with fibromyalgia compared with controls. Fibromyalgia patients (n = 116) and age-matched healthy controls (n = 144) were included in this observational and prospective cohort study. All subjects underwent visual acuity measurement and structural analysis of the RNFL using two OCT devices (Cirrus and Spectralis). Fibromyalgia patients were evaluated according to Giesecke's fibromyalgia subgroups, the Fibromyalgia Impact Questionnaire (FIQ), and the European Quality of Life-5 Dimensions (EQ5D) scale. We compared the differences between fibromyalgia patients and controls, and analyzed the correlations between OCT measurements, disease duration, fibromyalgia subgroups, severity, and quality of life. The impact on quality of life in fibromyalgia subgroups and in patients with different disease severity was also analyzed. A significant decrease in the RNFL was detected in fibromyalgia patients compared with controls using the two OCT devices: Cirrus OCT ganglion cell layer analysis registered a significant decrease in the minimum thickness of the inner plexiform layer (74.99±16.63 vs 79.36±3.38 μm, respectively; p = 0.023), nasal inferior, temporal inferior and temporal superior sectors (p = 0.040; 0.011 and 0.046 respectively). The Glaucoma application of the Spectralis OCT revealed thinning in the nasal, temporal inferior and temporal superior sectors (p = 0.009, 0.006, and 0.002 respectively) of fibromyalgia patients and the Axonal application in all sectors, except the nasal superior and temporal sectors. The odds ratio (OR) to estimate the size effect of FM in RNFL thickness was 1.39. RNFL atrophy was detected in patients with FIQ scores fibromyalgia (FIQ≥60) compared with patients with mild fibromyalgia (FIQfibromyalgia exhibited significant thinning in the

  15. Optic Nerve Head and Retinal Nerve Fiber Layer Differences Between Caribbean Black and African American Patients as Measured by Spectral Domain OCT.

    Science.gov (United States)

    Rao, Rohini; Dhrami-Gavazi, Elona; Al-Aswad, Lama; Ciarleglio, Adam; Cioffi, George A; Blumberg, Dana M

    2015-01-01

    There are well-established differences in optic nerve morphology between patients of African and European descent. Spectral domain optical coherence tomography (OCT) scanning has demonstrated these differences with respect to optic disc area (DA), average cup-disc ratio, cup volume, and nerve fiber layer thickness. However, the term "African descent" describes a heterogenous group with considerable variability. This study evaluates differences in optic nerve and retinal nerve fiber layer (RNFL) parameters as measured by Cirrus HD-OCT between Caribbean black and African American patients. A total of 25 African American subjects and 25 Caribbean black subjects with normal ocular examinations were consecutively recruited to this study. All patients received imaging of the optic nerve and nerve fiber layer with Cirrus HD-OCT. Optic nerve and RNFL parameters were evaluated for statistically significant differences using a t test. A mixed effect model for correlated data was then created to adjust outcome variables for (1) repeated measures and (2) optic nerve size. Two one-sided t tests were then utilized to determine equivalence. After adjustment for DA, RNFL thickness, cup volume, DA, inferior nerve fiber layer, and vertical cup-disc ratio demonstrated statistically significant equivalence between the 2 groups (P value fiber layer quadrant was significantly different between the 2 groups and may merit further investigation. Findings of this study suggest that optic nerve and RNFL morphology is markedly similar between Caribbean blacks and African Americans once adjusted for optic nerve size but cannot be considered equivalent in all measures, particularly in the superior nerve fiber layer.

  16. Brain imaging signatures of the relationship between epidermal nerve fibers and heat pain perception.

    Science.gov (United States)

    Tseng, Ming-Tsung; Kong, Yazhuo; Chiang, Ming-Chang; Chao, Chi-Chao; Tseng, Wen-Yih I; Hsieh, Sung-Tsang

    2015-11-15

    Although the small-diameter primary afferent fibers in the skin promptly respond to nociceptive stimuli and convey sensory inputs to the central nervous system, the neural signatures that underpin the relationship between cutaneous afferent fibers and pain perception remain elusive. We combined skin biopsy at the lateral aspect of the distal leg, which is used to quantify cutaneous afferent fibers, with fMRI, which is used to assess brain responses and functional connectivity, to investigate the relationship between cutaneous sensory nerves and the corresponding pain perception in the brain after applying heat pain stimulation to the dorsum of the right foot in healthy subjects. During painful stimulation, the degree of cutaneous innervation, as measured by epidermal nerve fiber density, was correlated with individual blood oxygen level-dependent (BOLD) signals of the posterior insular cortex and of the thalamus, periaqueductal gray, and rostral ventromedial medulla. Pain perception was associated with the activation of the anterior insular cortex and with the functional connectivity from the anterior insular cortex to the primary somatosensory cortex during painful stimulation. Most importantly, both epidermal nerve fiber density and activity in the posterior insular cortex showed a positive correlation with the strength of coupling under pain between the anterior insular cortex and the primary somatosensory cortex. Thus, our findings support the notion that the neural circuitry subserving pain perception interacts with the cerebral correlates of peripheral nociceptive fibers, which implicates an indirect role for skin nerves in human pain perception. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Retinal nerve fiber layer thickness is associated with lesion length in acute optic neuritis

    DEFF Research Database (Denmark)

    Kallenbach, K; Simonsen, Helle Juhl; Sander, B

    2010-01-01

    included 41 patients with unilateral optic neuritis and 19 healthy volunteers. All patients were evaluated and examined within 28 days of onset of symptoms. The peripapillary retinal nerve fiber layer thickness (RNFLT), an objective quantitative measure of optic nerve head edema, was measured by optical...... coherence tomography and the length and location of the inflammatory optic nerve lesion were evaluated using MRI. RESULTS: Ophthalmoscopically, 34% of the patients had papillitis. The retinal nerve fiber layer in affected eyes (mean 123.1 microm) was higher during the acute phase than that of fellow eyes......BACKGROUND: Acute optic neuritis occurs with and without papillitis. The presence of papillitis has previously been thought to imply an anterior location of the neuritis, but imaging studies seeking to test this hypothesis have been inconclusive. METHODS: This prospective observational cohort study...

  18. Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants.

    Science.gov (United States)

    Caldas, Fernanda Ferreira; Cardoso, Carolina Costa; Barreto, Monique Antunes de Souza Chelminski; Teixeira, Marina Santos; Hilgenberg, Anacléia Melo da Silva; Serra, Lucieny Silva Martins; Bahmad Junior, Fayez

    2016-01-01

    The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve. The neural response telemetry is used in order to measure the electrically evoked compound action potential of the auditory nerve. To analyze the electrically evoked compound action potential, through the neural response telemetry, in children with bilateral cochlear implants. This is an analytical, prospective, longitudinal, historical cohort study. Six children, aged 1-4 years, with bilateral cochlear implant were assessed at five different intervals during their first year of cochlear implant use. There were significant differences in follow-up time (p=0.0082) and electrode position (p=0.0019) in the T-NRT measure. There was a significant difference in the interaction between time of follow-up and electrode position (p=0.0143) when measuring the N1-P1 wave amplitude between the three electrodes at each time of follow-up. The electrically evoked compound action potential measurement using neural response telemetry in children with bilateral cochlear implants during the first year of follow-up was effective in demonstrating the synchronized bilateral development of the peripheral auditory pathways in the studied population. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  19. The Association between Serum Cytokines and Damage to Large and Small Nerve Fibers in Diabetic Peripheral Neuropathy

    Directory of Open Access Journals (Sweden)

    Francesca Magrinelli

    2015-01-01

    Full Text Available Diabetic peripheral neuropathy (DPN is a frequent complication of type 2 diabetes mellitus (DM and may involve small and large peripheral nerve fibers. Recent evidence suggests a role of cytokines in DPN. The paper is aimed at exploring whether the serum concentration of cytokines is associated with small and large nerve fiber function and with neuropathic pain (NP. We recruited a group of 32 type 2 DM patients who underwent serum cytokines (TNF-α, IL-2, IL-4, IL-6, and IL-10 dosage as well as electrodiagnostic and quantitative sensory testing (QST assessment to explore damage to large and small nerve fibers. Raised serum levels of IL-6 and IL-10 correlated with markers of large nerve fiber sensory and motor axonal damage. Raised IL-10 serum level was associated with signs of motor nerve demyelination. No differences were found in pain characteristics and electrodiagnostic and QST markers of small nerve fiber function in relation to cytokines serum levels. IL-6 and IL-10 serum levels were associated with large nerve fiber damage but not to small fibers function or NP. IL-6 and IL-10 cytokines might play a role in the pathogenesis of nerve fiber damage or represent a compensatory or neuroprotective mechanism.

  20. NON-INVASIVE EVALUATION OF NERVE CONDUCTION IN SMALL DIAMETER FIBERS IN THE RAT.

    Science.gov (United States)

    Zotova, Elena G; Arezzo, Joseph C

    2013-01-01

    A novel non-invasive technique was applied to measure velocity within slow conducting axons in the distal extreme of the sciatic nerve (i.e., digital nerve) in a rat model. The technique is based on the extraction of rectified multiple unit activity (MUA) from in vivo whole nerve compound responses. This method reliably identifies compound action potentials in thinly myelinated fibers conducting at a range of 9-18 m/s (Aδ axons), as well as in a subgroup of unmylinated C fibers conducting at approximately 1-2 m/s. The sensitivity of the method to C-fiber conduction was confirmed by the progressive decrement of the responses in the 1-2 m/s range over a 20-day period following the topical application of capsaicin (ANOVA p <0.03). Increasing the frequency of applied repetitive stimulation over a range of 0.75 Hz to 6.0 Hz produced slowing of conduction and a significant decrease in the magnitude of the compound C-fiber response (ANOVA p <0.01). This technique offers a unique opportunity for the non-invasive, repeatable, and quantitative assessment of velocity in the subsets of Aδ and C fibers in parallel with evaluation of fast nerve conduction.

  1. Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning.

    Directory of Open Access Journals (Sweden)

    Elena Garcia-Martin

    Full Text Available To investigate whether fibromyalgia induces axonal damage in the optic nerve that can be detected using optical coherence tomography (OCT, as the retinal nerve fiber layer (RNFL is atrophied in patients with fibromyalgia compared with controls.Fibromyalgia patients (n = 116 and age-matched healthy controls (n = 144 were included in this observational and prospective cohort study. All subjects underwent visual acuity measurement and structural analysis of the RNFL using two OCT devices (Cirrus and Spectralis. Fibromyalgia patients were evaluated according to Giesecke's fibromyalgia subgroups, the Fibromyalgia Impact Questionnaire (FIQ, and the European Quality of Life-5 Dimensions (EQ5D scale. We compared the differences between fibromyalgia patients and controls, and analyzed the correlations between OCT measurements, disease duration, fibromyalgia subgroups, severity, and quality of life. The impact on quality of life in fibromyalgia subgroups and in patients with different disease severity was also analyzed.A significant decrease in the RNFL was detected in fibromyalgia patients compared with controls using the two OCT devices: Cirrus OCT ganglion cell layer analysis registered a significant decrease in the minimum thickness of the inner plexiform layer (74.99±16.63 vs 79.36±3.38 μm, respectively; p = 0.023, nasal inferior, temporal inferior and temporal superior sectors (p = 0.040; 0.011 and 0.046 respectively. The Glaucoma application of the Spectralis OCT revealed thinning in the nasal, temporal inferior and temporal superior sectors (p = 0.009, 0.006, and 0.002 respectively of fibromyalgia patients and the Axonal application in all sectors, except the nasal superior and temporal sectors. The odds ratio (OR to estimate the size effect of FM in RNFL thickness was 1.39. RNFL atrophy was detected in patients with FIQ scores <60 (patients in early disease stages compared with controls in the temporal inferior sector (78.74±17.75 vs 81.65±3

  2. Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

    DEFF Research Database (Denmark)

    Mehraei, Golbarg; Paredes Gallardo, Andreu; Shinn-Cunningham, Barbara G.

    2017-01-01

    In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels...... and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave......-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low...

  3. Peripapillary retinal nerve fiber layer and choroidal thickness in cirrhosis patients

    Directory of Open Access Journals (Sweden)

    M.Orcun Akdemir

    2015-12-01

    Full Text Available ABSTRACT Purpose: To evaluate the effect of cirrhosis on peripapillary retinal nerve fiber layer and choroidal thickness with enhanced depth imaging optical coherence tomography. Methods: This cross sectional, single center study was undertaken at Bulent Ecevit University Ophthalmology department with the participation of internal medicine, Gastroenterology department. Patients who were treated with the diagnosis of cirrhosis (n=75 were examined in the ophthalmology clinic. Age and sex matched patients (n=50 who were healthy and met the inclusion, exclusion criteria were included in the study. Complete ophthalmological examination included visual acuity with Snellen chart, intraocular pressure measurement with applanation tonometry, biomicroscopy of anterior and posterior segments, gonioscopy, axial length measurement, visual field examination, peripapillary retinal nerve fiber layer, central macular and subfoveal choroidal thickness measurements. Results: The difference between intraocular pressure values was not statistically significant between cirrhosis and control group (p=0.843. However, mean peripapillary retinal nerve fiber layer thickness was significantly thinner in cirrhosis group in all regions (p<0.001 and subfoveal choroidal thickness was significantly thinner in cirrhosis group also (p<0.001. Moreover, central macular thickness of cirrhosis group was significantly thicker than the control group (p=0.001. Conclusion: Peripapillary retinal nerve fiber layer and subfoveal choroidal thickness was significantly thinner in cirrhosis patients.

  4. Diffusion tensor imaging for nerve fiber bundles in the brain stem and spinocerebellar degeneration

    International Nuclear Information System (INIS)

    Honma, Tsuguo

    2009-01-01

    Diffusion tensor imaging (DTI) can create an image of the anisotropic nature of diffusion and express it quantitatively. Nerve fibers have a large anisotropic diffusion, and it is possible to obtain images of the nerve fiber bundle. The purpose of this study is to observe the nerve fiber bundles in the brain stem using DTI and study its potential for diagnosing the type of spinocerebellar degeneration (SCD). Fractional anisotropy (FA) maps and 3D-tractography images were obtained for 41 subjects with no brain stem abnormalities. We created an apparent diffusion coefficient (ADC) map and an FA map using DTI for 16 subjects in the disease group (11 with hereditary SCD and 5 with non-hereditary SCD) and 25 in the control group. The diffusion value of the pons and middle cerebellar peduncle was measured using ADC, and the degree of anisotropic diffusion was measured using FA. The pyramidal tract, superior cerebellar peduncle, and inferior cerebellar peduncle were clearly demonstrated for all cases. ADC for the middle cerebellar peduncle in spinocerebellar ataxin (SCA)1 was significantly higher, similar to that for the pons in dentatorubro-pallidoluysian atrophy (DRPLA). In MSA-C, ADC for both the pons and middle cerebellar peduncle was significantly elevated and FA was significantly decreased. There were no significant changes in SCA3. We could observe the nerve fiber bundles in the brain stem using DTI. FA and ADC measurements with DTI can aid in diagnosing the type of SCD. (author)

  5. Split bundle detection in polarimetric images of the human retinal nerve fiber layer

    NARCIS (Netherlands)

    Vermeer, K. A.; Reus, N. J.; Vos, F. M.; Lemij, H. G.; Vossepoel, A. M.

    2007-01-01

    One method for assessing pathological retinal nerve fiber layer (NFL) appearance is by comparing the NFL to normative values, derived from healthy subjects. These normative values will be more specific when normal physiological differences are taken into account. One common variation is a split

  6. Retinal nerve fiber layer thickness map determined from optical coherence tomography images

    NARCIS (Netherlands)

    Mujat, M.; Chan, R. C.; Cense, B.; Park, B.H.; Joo, C.; Akkin, T.; Chen, TC; de Boer, JF

    2005-01-01

    We introduce a method to determine the retinal nerve fiber layer (RNFL) thickness in OCT images based on anisotropic noise suppression and deformable splines. Spectral-Domain Optical Coherence Tomography (SDOCT) data was acquired at 29 kHz A-line rate with a depth resolution of 2.6 mum and a depth

  7. Reduction in Retinal Nerve Fiber Layer Thickness in Young Adults with Autism Spectrum Disorders

    Science.gov (United States)

    Emberti Gialloreti, Leonardo; Pardini, Matteo; Benassi, Francesca; Marciano, Sara; Amore, Mario; Mutolo, Maria Giulia; Porfirio, Maria Cristina; Curatolo, Paolo

    2014-01-01

    Recent years have seen an increase in the use of retinal nerve fiber layer (RNFL) evaluation as an easy-to-use, reproducible, proxy-measure of brain structural abnormalities. Here, we evaluated RNFL thickness in a group of subjects with high functioning autism (HFA) or with Asperger Syndrome (AS) to its potential as a tool to study autism…

  8. Comparisons of retinal nerve fiber layer thickness changes after macular hole surgery

    Directory of Open Access Journals (Sweden)

    Nelson Chamma Capelanes

    Full Text Available ABSTRACT Purpose: To compare postoperative changes in retinal nerve fiber layer thickness in patients with macular holes treated with vitrectomy with Brilliant Blue-assisted internal limiting membrane peeling. Methods: Twenty-two eyes of 20 patients with macular holes were studied. Each eye was selected to undergo Brilliant Blue-assisted internal limiting membrane peeling. The circumferential retinal nerve fiber layer thickness was determined using spectral domain optical coherence tomography preoperatively and 2 months postoperatively. Mean overall and sectoral retinal nerve fiber layer thicknesses were obtained for each patient. Results: There was no statistically significant difference (p≥0.05 between the pre- and post-treatment measurements in relation to each CFN variable, i.e., on average, pre-treatment measures were the same as post-treatment measures. Furthermore, despite the differences between the pre- and post-treatment measures always being positive (pre-post >0, they are not statistically significant. Conclusions: This study showed no significant decrease in retinal nerve fiber layer thickness measurements after macular holes surgery, regardless of age or sex.

  9. Sound and vibration sensitivity of VIIIth nerve fibers in the grassfrog, Rana temporaria

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Jørgensen, M B

    1996-01-01

    thresholds from 0.02 cm/s2. The sound and vibration sensitivity was compared for each fiber using the offset between the rate-level curves for sound and vibration stimulation as a measure of relative vibration sensitivity. When measured in this way relative vibration sensitivity decreases with frequency from......We have studied the sound and vibration sensitivity of 164 amphibian papilla fibers in the VIIIth nerve of the grassfrog, Rana temporaria. The VIIIth nerve was exposed using a dorsal approach. The frogs were placed in a natural sitting posture and stimulated by free-field sound. Furthermore......, the animals were stimulated with dorso-ventral vibrations, and the sound-induced vertical vibrations in the setup could be canceled by emitting vibrations in antiphase from the vibration exciter. All low-frequency fibers responded to both sound and vibration with sound thresholds from 23 dB SPL and vibration...

  10. Study of nerve fibers nature reinforcing duodenal contractions by electrical stimulation of sympathetic nerve

    Directory of Open Access Journals (Sweden)

    Sveshnikov D.S.

    2011-09-01

    Full Text Available The subject of the article is to investigate the mechanism of increased reactions by electrical stimulation of the sympathetic nerve. Materials and methods: Experiments on dogs have shown that stimulant reactions during blockade of a-adrenergic by phentolamine and (3-adrenergic receptors with propranolol were completely eliminated by lizer-gol —the blocker of 5-HT12-receptors. Results: Infusion of lizergol did not influence on duodenal motor activity and the function of the vagus nerve. Conclusion: Effector neuron is found out to be serotonergic and its action is provided by 5-HT1 2 receptors

  11. Effects of cholinergic compounds on the axon-Schwann cell relationship in the squid nerve fiber.

    Science.gov (United States)

    Villegas, J

    1975-04-01

    The effects of acetylcholine, carbamylcholine, D-tubocurarine, eserine, and alpha-bungarotoxin on the Schwann cell electrical potential of resting and stimulated squid nerve fibers were studied. Acetylcholine (10-7 M) and barbamylcholine (10-6 M) induce a prolonged hyper polarization in the Schwann cells of the unstimulated nerve fiber. In the presence of carbamylcholine (10-6 M) the behavior of the Schwann cell membrane to changes in the external potassium concentration approximates the behavior of an ideal potassium electrode. D-Tubocurarine (10-9 M) blocks the hyperpolarizing effects of nerve impulse trains and carbamylcholine (10-6 M), whereas at the same concentration eserine prolongs the Schwann cell hyperpolarizations induced by axon stimulation or by acetylcholine (10-7 M). alpha-Bungarotoxin (10-9M) also blocks the hyperpolarizing effect of nerve impulse trains and of carbamylcholine. D-Tubocurarine (10-5M) protects the Schwann cells against the irreversible action of alpha-bungarotoxin. These results show the existence of acetylcholine receptors in the Schwann cell membrane. Preliminary measurements of the binding of 125I-alpha bungarotoxin to the plasma membranes isolated from squid nerves also indicate the presence of acetylcholine receptors. These findings support the involvement of cholinergic mechanisms in the axon-Schwann cell relationship previously described.

  12. Predicting dynamic range and intensity discrimination for electrical pulse-train stimuli using a stochastic auditory nerve model: the effects of stimulus noise.

    Science.gov (United States)

    Xu, Yifang; Collins, Leslie M

    2005-06-01

    This work investigates dynamic range and intensity discrimination for electrical pulse-train stimuli that are modulated by noise using a stochastic auditory nerve model. Based on a hypothesized monotonic relationship between loudness and the number of spikes elicited by a stimulus, theoretical prediction of the uncomfortable level has previously been determined by comparing spike counts to a fixed threshold, Nucl. However, no specific rule for determining Nucl has been suggested. Our work determines the uncomfortable level based on the excitation pattern of the neural response in a normal ear. The number of fibers corresponding to the portion of the basilar membrane driven by a stimulus at an uncomfortable level in a normal ear is related to Nucl at an uncomfortable level of the electrical stimulus. Intensity discrimination limens are predicted using signal detection theory via the probability mass function of the neural response and via experimental simulations. The results show that the uncomfortable level for pulse-train stimuli increases slightly as noise level increases. Combining this with our previous threshold predictions, we hypothesize that the dynamic range for noise-modulated pulse-train stimuli should increase with additive noise. However, since our predictions indicate that intensity discrimination under noise degrades, overall intensity coding performance may not improve significantly.

  13. [Impact of hypoglycemic episodes on nerves conduction and auditory and visual evoked potentials in children with type 1 diabetes].

    Science.gov (United States)

    Wysocka-Mincewicz, Marta; Trippenbach-Dulska, Hanna; Emeryk-Szajewska, Barbara; Zakrzewska-Pniewska, Beata; Kochanek, Krzysztof; Pańkowska, Ewa

    2007-01-01

    Hypoglycemia is an acute disturbance of energy, especially impacting the central nervous system, but direct influence on peripheral nervous function is not detected. The aim of the study was to establish the influence of hypoglycemic moderate and severe episodes on the function of peripheral nerves, hearing and visual pathway. 97 children with type 1 diabetes (mean age 15.4+/-2.16 years, mean duration of diabetes 8.11+/-2.9 years, mean HbA1c 8,58+/-1.06%), at least 10 years old and with at least 3 years duration of diabetes, were included to study. Nerve conduction studies, visual (VEP) and auditory (ABR) evoked potentials were performed with standard surface stimulating and recording techniques. Moderate hypoglycemic episodes were defined as events of low glycemia requiring help of another person but without loss of consciousness and/or convulsions but recurrent frequently in at least one year. Severe hypoglycemia was defined as events with loss of consciousness and/or convulsions. Univariate ANOVA tests of significance or H Kruskal-Wallis test were used, depending on normality of distribution. The subgroups with a history of hypoglycemic episodes had significant delay in all conduction parameters in the sural nerve (amplitude pwave III latency and interval I-III in subgroups with episodes of hypoglycemia (pwave III and interval I-III. Frequent moderate hypoglycemic episodes were strong risk factors for damage of the peripheral and central nervous systems, comparable with impact of several severe hypoglycemias.

  14. Chronic migraine is associated with reduced corneal nerve fiber density and symptoms of dry eye.

    Science.gov (United States)

    Kinard, Krista I; Smith, A Gordon; Singleton, J Robinson; Lessard, Margaret K; Katz, Bradley J; Warner, Judith E A; Crum, Alison V; Mifflin, Mark D; Brennan, Kevin C; Digre, Kathleen B

    2015-04-01

    We used in vivo corneal confocal microscopy to investigate structural differences in the sub-basal corneal nerve plexus in chronic migraine patients and a normal population. We used a validated questionnaire and tests of lacrimal function to determine the prevalence of dry eye in the same group of chronic migraine patients. Activation of the trigeminal system is involved in migraine. Corneal nociceptive sensation is mediated by trigeminal axons that synapse in the gasserian ganglion and the brainstem, and serve nociceptive, protective, and trophic functions. Noninvasive imaging of the corneal sub-basal nerve plexus is possible with in vivo corneal confocal microscopy. For this case-control study, we recruited chronic migraine patients and compared them with a sex- and age-similar group of control subjects. Patients with peripheral neuropathy, a disease known to be associated with a peripheral neuropathy, or prior corneal or intraocular surgery were excluded. Participants underwent in vivo corneal confocal microscopy using a Heidelberg Retinal Tomography III confocal microscope with a Rostock Cornea Module. Nerve fiber length, nerve branch density, nerve fiber density, and tortuosity coefficient were measured using established methodologies. Migraine participants underwent testing of basal tear production with proparacaine, corneal sensitivity assessment with a cotton-tip applicator, measurement of tear break-up time, and completion of a validated dry eye questionnaire. A total of 19 chronic migraine patients and 30 control participants completed the study. There were no significant differences in age or sex. Nerve fiber density was significantly lower in migraine patients compared with controls (48.4 ± 23.5 vs. 71.0 ± 15.0 fibers/mm2 , P dry eye syndrome. We found that in the sample used in this study, the presence of structural changes in nociceptive corneal axons lends further support to the hypothesis that the trigeminal system plays a critical role

  15. CAPSAICIN-SENSITIVE SENSORY NERVE FIBERS CONTRIBUTE TO THE GENERATION AND MAINTENANCE OF SKELETAL FRACTURE PAIN

    OpenAIRE

    Jimenez-Andrade, Juan Miguel; Bloom, Aaron P.; Mantyh, William G.; Koewler, Nathan J.; Freeman, Katie T.; Delong, David; Ghilardi, Joseph R.; Kuskowski, Michael A.; Mantyh, Patrick W.

    2009-01-01

    Although skeletal pain can have a marked impact on a patient’s functional status and quality of life, relatively little is known about the specific populations of peripheral nerve fibers that drive non-malignant bone pain. In the present report, neonatal male Sprague Dawley rats were treated with capsaicin or vehicle and femoral fracture was produced when the animals were young adults (15–16 weeks old). Capsaicin treatment, but not vehicle, resulted in a significant (>70%) depletion in the de...

  16. Normal axonal ion channel function in large peripheral nerve fibers following chronic ciguatera sensitization.

    Science.gov (United States)

    Vucic, Steve; Kiernan, Matthew C

    2008-03-01

    Although the acute clinical effects of ciguatera poisoning, due to ingestion of ciguatoxin, are mediated by activation of transient Na+ channels, the mechanisms underlying ciguatera sensitization remain undefined. Axonal excitability studies were performed by stimulating the median motor and sensory nerves in two patients with ciguatera sensitization. Excitability parameters were all within normal limits, thereby arguing against dysfunction of axonal membrane ion channels in large-diameter fibers in ciguatera sensitization.

  17. Scanning laser polarimetry retinal nerve fiber layer thickness measurements after LASIK.

    Science.gov (United States)

    Zangwill, Linda M; Abunto, Teresa; Bowd, Christopher; Angeles, Raymund; Schanzlin, David J; Weinreb, Robert N

    2005-02-01

    To compare retinal nerve fiber layer (RNFL) thickness measurements before and after LASIK. Cohort study. Twenty participants undergoing LASIK and 14 normal controls. Retinal nerve fiber layer thickness was measured before LASIK and approximately 3 months after surgery in one eye each of 20 patients using a scanning laser polarimeter (GDx Nerve Fiber Analyzer) with fixed corneal compensation (FCC), one with variable corneal compensation (GDx VCC), and optical coherence tomography (OCT). Fourteen normal controls also were tested at baseline and approximately 3 months later. Retinal nerve fiber layer thicknesses measured with the GDx FCC, GDx VCC, and OCT. At baseline, mean (95% confidence interval [CI]) RNFL thicknesses for the GDx FCC, GDx VCC, and OCT were 78.1 microm (72.2-83.9), 54.3 microm (52.7-56.0), and 96.8 microm (93.2-100.5), respectively. In both LASIK and control groups, there were no significant changes between baseline and follow-up examinations in GDx VCC and OCT RNFL thickness measurements globally or in the superior and inferior quadrants (mean change, FCC measurements between baseline and follow-up. In LASIK patients, significant reductions were observed in GDx FCC RNFL measurements. Average absolute values of the mean (95% CI) change in thickness were 12.4 microm (7.7-17.2), 15.3 microm (9.6-20.9), and 12.9 microm (7.6-18.1) for GDx FCC RNFL measurements superiorly, inferiorly, and globally, respectively (all Ps FCC RNFL thickness measurements after LASIK is a measurement artifact and is most likely due to erroneous compensation for corneal birefringence. With scanning laser polarimetry, it is mandatory to compensate individually for change in corneal birefringence after LASIK to ensure accurate RNFL assessment.

  18. Morphometric analysis of the fiber populations of the rat sciatic nerve, its spinal roots, and its major branches

    NARCIS (Netherlands)

    Prodanov, D.P.; Feierabend, H.K.P.

    2007-01-01

    Correspondence between the nerve composition and the functional characteristics of its fiber populations is not always evident. To investigate such correspondence and to give a systematic picture of the morphology of the rat hind limb nerves, extensive morphometric study was performed on the sciatic

  19. A simple method for fabrication of electrospun fibers with controlled degree of alignment having potential for nerve regeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Vimal, Sunil Kumar; Ahamad, Nadim; Katti, Dhirendra S., E-mail: dsk@iitk.ac.in

    2016-06-01

    In peripheral nerve injuries where direct suturing of nerve endings is not feasible, nerve regeneration has been facilitated through the use of artificially aligned fibrous scaffolds that provide directional growth of neurons to bridge the gap. The degree of fiber alignment is crucial and can impact the directionality of cells in a fibrous scaffold. While there have been multiple approaches that have been used for controlling fiber alignment, however, they have been associated with a compromised control on other properties, such as diameter, morphology, curvature, and topology of fibers. Therefore, the present study demonstrates a modified electrospinning set-up, that enabled fabrication of electrospun fibers with controlled degree of alignment from non-aligned (NA), moderately aligned (MA, 75%) to highly aligned (HA, 95%) sub-micron fibers while keeping other physical properties unchanged. The results demonstrate that the aligned fibers (MA and HA) facilitated directional growth of human astrocytoma cells (U373), wherein the aspect ratio of cells was found to increase with an increase in degree of fibers alignment. In contrast to NA and MA fibers, the HA fibers showed improved contact guidance to U373 cells that was demonstrated by a significantly higher cell aspect ratio and nuclear aspect ratio. In conclusion, the present study demonstrated a modified electrospinning setup to fabricate differentially aligned fibrous scaffolds with the HA fibers showing potential for use in neural tissue engineering. - Highlights: • Modified electrospinning set-up for fabrication of fibers with controlled alignment • Three parameter-based control on the degree of alignment of fibers • The aligned fibers enhanced cell elongation and cell-cell contact. • The aligned fibers show potential for use in nerve regeneration.

  20. Growth Factor and Laminin Effect with Muscular Fiber Sheath on Repairing of the Sciatica Nerve

    Directory of Open Access Journals (Sweden)

    S Torabi

    2014-01-01

    Background & aim: Peripheral nerve injuries which can lead to a physical disability. If the defect is very low, direct suture without tension on both ends of the cut nerve regeneration is considered as a standard procedure. Otherwise, to reconstruct the axons, the gap must be filled by graft material in order to the guidance. Due to the similarity of the matrix tubular skeletal muscle and nerve muscles graft was used to repair in this study. Methods: In the present experimental study, 42 female Wistar rats were divided into three groups and underwent surgery. In the first group a narrow strip of muscle was prepared by freezing – thawing, and later sutured between the distal and proximal sciatic nerve. In the second group, the gap caused by muscle graft was regenerated and the nerve growth factor and laminin was injected into the graft. In the control group, the two ends of the cut nerve were hidden beneath the adjacent muscles. Next, a group of rats with sciatic functional index was investigated for the behavioral. On the other group were examined for histological studies after two months. Results: Sciatic functional index and Mean counts of myelinated fibers in two graft groups compared with the control group was significant p<0.05. Statistical analysis was performed using ANOVA test. Conclusion: co-axially aligned muscle grafts were an appropriate alternative substitute for repairing. It seems that the nerve growth factor and laminin have a positive role in axonal regeneration and functional recovery acceleration. Key words: Sciatic Functional Index, muscle graft, NGF, Laminin

  1. Differentiation of Nerve Fibers Storing CGRP and CGRP Receptors in the Peripheral Trigeminovascular System

    DEFF Research Database (Denmark)

    Eftekhari, Sajedeh; Warfvinge, Karin; Blixt, Frank W

    2013-01-01

    Primary headaches such as migraine are postulated to involve the activation of sensory trigeminal pain neurons that innervate intracranial blood vessels and the dura mater. It is suggested that local activation of these sensory nerves may involve dural mast cells as one factor in local inflammation...... and in human dural vessels. The relative distributions of CGRP, CLR, and RAMP1 were evaluated with respect to each other and in relationship to mast cells, myelin, substance P, neuronal nitric oxide synthase, pituitary adenylate cyclase-activating polypeptide, and vasoactive intestinal peptide. CGRP expression...... was found in thin unmyelinated fibers, whereas CLR and RAMP1 were expressed in thicker myelinated fibers coexpressed with an A-fiber marker. CLR and RAMP1 immunoreactivity colocalized with mast cell tryptase in rodent; however, expression of both receptor components was not observed in human mast cells...

  2. Renal hemodynamic effects of activation of specific renal sympathetic nerve fiber groups.

    Science.gov (United States)

    DiBona, G F; Sawin, L L

    1999-02-01

    To examine the effect of activation of a unique population of renal sympathetic nerve fibers on renal blood flow (RBF) dynamics, anesthetized rats were instrumented with a renal sympathetic nerve activity (RSNA) recording electrode and an electromagnetic flow probe on the ipsilateral renal artery. Peripheral thermal receptor stimulation (external heat) was used to activate a unique population of renal sympathetic nerve fibers and to increase total RSNA. Total RSNA was reflexly increased to the same degree with somatic receptor stimulation (tail compression). Arterial pressure and heart rate were increased by both stimuli. Total RSNA was increased to the same degree by both stimuli but external heat produced a greater renal vasoconstrictor response than tail compression. Whereas both stimuli increased spectral density power of RSNA at both cardiac and respiratory frequencies, modulation of RBF variability by fluctuations of RSNA was small at these frequencies, with values for the normalized transfer gain being approximately 0.1 at >0.5 Hz. During tail compression coherent oscillations of RSNA and RBF were found at 0.3-0.4 Hz with normalized transfer gain of 0.33 +/- 0.02. During external heat coherent oscillations of RSNA and RBF were found at both 0.2 and 0.3-0.4 Hz with normalized transfer gains of 0. 63 +/- 0.05 at 0.2 Hz and 0.53 +/- 0.04 to 0.36 +/- 0.02 at 0.3-0.4 Hz. Renal denervation eliminated the oscillations in RBF at both 0.2 and 0.3-0.4 Hz. These findings indicate that despite similar increases in total RSNA, external heat results in a greater renal vasoconstrictor response than tail compression due to the activation of a unique population of renal sympathetic nerve fibers with different frequency-response characteristics of the renal vasculature.

  3. Survey of Nerve Fiber Layer Thickness in Anisometropic and Strabismic Amblyopia

    Directory of Open Access Journals (Sweden)

    Reza Soltani Moghaddam

    2017-02-01

    Full Text Available . To investigate the effect of anisometropic and strabismic amblyopia on the nerve fiber layer thickness. This cross-sectional study was done on 54 amblyopic subjects, equally in both strabismic and anisometropic groups. The thickness otonerve fiber layer measured in superior, inferior, nasal, temporal quadrants and as a whole in both eyes of both groups. The means of thickness were compared in amblyopic and sound eyes. In strabismus group, the average nerve fiber layer thickness of the sound eye , in superior, inferior, nasal and temporal quadrants and as a whole were 113.23±14, 117.37±25, 68.96±6, 69.55±14 and 93.40±8 microns respectively. In amblyopic eyes of the same group, these measurements were 103.11±18, 67.74±11, and 69.59±16 and 89.59±12 microns in superior, inferior, nasal, temporal quadrants and as whole respectively. In anisometropic groups, the sound eye measurements were as 130.96±22, 129.07±29, 80.62±12, and 83.88±20 and 107.7±13 microns in superior, inferior, nasal and temporal quadrants and as a whole orderly. In amblyopic eyes of this group the mean thicknesses were 115.63±29, 133.15±25, 78.8±15, 80.2±16 and 109.17±21 microns in superior, inferior, nasal, temporal quadrants and as a whole respectively. Statistically, there were no significant differences between amblyopic and sound eyes (P>0.5. Our study did not support any significant change in a nerve fiber layer thickness of amblyopic patients; however, decreased thickness in superior and nasal quadrants of strabismic amblyopia and except inferior quadrant and as a whole. These measurements may be a clue for management and prognosis of amblyopia in old age.

  4. Towards Clinical Application of Neurotrophic Factors to the Auditory Nerve; Assessment of Safety and Efficacy by a Systematic Review of Neurotrophic Treatments in Humans

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    Aren Bezdjian

    2016-11-01

    Full Text Available Animal studies have evidenced protection of the auditory nerve by exogenous neurotrophic factors. In order to assess clinical applicability of neurotrophic treatment of the auditory nerve, the safety and efficacy of neurotrophic therapies in various human disorders were systematically reviewed. Outcomes of our literature search included disorder, neurotrophic factor, administration route, therapeutic outcome, and adverse event. From 2103 articles retrieved, 20 randomized controlled trials including 3974 patients were selected. Amyotrophic lateral sclerosis (53% was the most frequently reported indication for neurotrophic therapy followed by diabetic polyneuropathy (28%. Ciliary neurotrophic factor (50%, nerve growth factor (24% and insulin-like growth factor (21% were most often used. Injection site reaction was a frequently occurring adverse event (61% followed by asthenia (24% and gastrointestinal disturbances (20%. Eighteen out of 20 trials deemed neurotrophic therapy to be safe, and six out of 17 studies concluded the neurotrophic therapy to be effective. Positive outcomes were generally small or contradicted by other studies. Most non-neurodegenerative diseases treated by targeted deliveries of neurotrophic factors were considered safe and effective. Hence, since local delivery to the cochlea is feasible, translation from animal studies to human trials in treating auditory nerve degeneration seems promising.

  5. Pulp nerve fibers distribution of human carious teeth: An immunohistochemical study

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    Tetiana Haniastuti

    2010-12-01

    Full Text Available Background: Human dental pulp is richly innervated by trigeminal afferent axons that subserve nociceptive function. Accordingly, they respond to stimuli that induce injury to the pulp tissue. An injury to the nerve terminals and other tissue components in the pulp stimulate metabolic activation of the neurons in the trigeminal ganglion which result in morphological changes in the peripheral nerve terminals. Purpose: The aim of the study was to observe caries-related changes in the distribution of human pulpal nerve. Methods: Under informed consents, 15 third molars with caries at various stages of decay and 5 intact third molars were extracted because of orthodontic or therapeutic reasons. All samples were observed by micro-computed tomography to confirm the lesion condition 3-dimensionally, before decalcifying with 10% EDTA solution (pH 7.4. The specimens were then processed for immunohistochemistry using anti-protein gene products (PGP 9.5, a specific marker for the nerve fiber. Results: In normal intact teeth, PGP 9.5 immunoreactive nerve fibers were seen concentrated beneath the odontoblast cell layer. Nerve fibers exhibited an increased density along the pulp-dentin border corresponding to the carious lesions. Conclusion: Neural density increases throughout the pulp chamber with the progression of caries. The activity and pathogenicity of the lesion as well as caries depth, might influence the degree of neural sprouting.Latar belakang: Pulpa gigi manusia diinervasi oleh serabut saraf trigeminal yang berespon terhadap stimuli penyebab perlukaan dengan menimbulkan rasa sakit. Perlukaan pada akhiran saraf dan komponen lain dari pulpa akan menstimulasi aktivasi metabolik dari neuron pada ganglion trigeminal sehingga mengakibatkan perubahan morfologi pada akhiran saraf perifer. Tujuan: Penelitian ini bertujuan untuk mengamati perubahan distribusi saraf pada pulpa gigi manusia yang disebabkan oleh proses karies. Metode: Penelitian ini menggunakan

  6. Topiramate improves neurovascular function, epidermal nerve fiber morphology, and metabolism in patients with type 2 diabetes mellitus

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    Boyd A

    2010-12-01

    Full Text Available Amanda L Boyd, Patricia M Barlow, Gary L Pittenger, Kathryn F Simmons, Aaron I VinikDepartment of Internal Medicine, Eastern Virginia Medical School, Norfolk, VA, USAPurpose: To assess the effects of topiramate on C-fiber function, nerve fiber morphology, and metabolism (including insulin sensitivity, obesity, and dyslipidemia in type 2 diabetes.Patients and methods: We conducted an 18-week, open-label trial treating patients with topiramate. Twenty subjects with type 2 diabetes and neuropathy (61.5 ± 1.29 years; 15 male, 5 female were enrolled and completed the trial. Neuropathy was evaluated by total neuropathy scores, nerve conduction studies, quantitative sensory tests, laser Doppler skin blood flow, and intraepidermal nerve fibers in skin biopsies.Results: Topiramate treatment improved symptoms compatible with C-fiber dysfunction. Weight, blood pressure, and hemoglobin A1c also improved. Laser Doppler skin blood flow improved significantly after 12 weeks of treatment, but returned to baseline at 18 weeks. After 18 weeks of treatment there was a significant increase in intraepidermal nerve fiber length at the forearm, thigh, and proximal leg. Intraepidermal nerve fiber density was significantly increased by topiramate in the proximal leg.Conclusion: This study is the first to demonstrate that it is possible to induce skin intraepidermal nerve fiber regeneration accompanied by enhancement of neurovascular function, translating into improved symptoms as well as sensory nerve function. The simultaneous improvement of selective metabolic indices may play a role in this effect, but this remains to be determined.Keywords: diabetic neuropathy, skin blood flow, skin biopsy, diabetes

  7. Effect of duration and severity of migraine on retinal nerve fiber layer, ganglion cell layer, and choroidal thickness.

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    Abdellatif, Mona K; Fouad, Mohamed M

    2018-03-01

    To investigate the factors in migraine that have the highest significance on retinal and choroidal layers' thickness. Ninety patients with migraine and 40 age-matched healthy participants were enrolled in this observational, cross-sectional study. After full ophthalmological examination, spectral domain-optical coherence tomography was done for all patients measuring the thickness of ganglion cell layer and retinal nerve fiber layer. Enhanced depth imaging technique was used to measure the choroidal thickness. There was significant thinning in the superior and inferior ganglion cell layers, all retinal nerve fiber layer quadrants, and all choroidal quadrants (except for the central subfield) in migraineurs compared to controls. The duration of migraine was significantly correlated with ganglion cell layer, retinal nerve fiber layer, and all choroidal quadrants, while the severity of migraine was significantly correlated with ganglion cell layer and retinal nerve fiber layer only. Multiregression analysis showed that the duration of migraine is the most important determinant factor of the superior retinal nerve fiber layer quadrant (β = -0.375, p = 0.001) and in all the choroidal quadrants (β = -0.531, -0.692, -0.503, -0.461, -0.564, respectively, p  layer quadrants (β = -0.256, -0.335, -0.308; p  = 0.036, 0.005, 0.009, respectively) and the inferior ganglion cell layer hemisphere (β = -0.377 and p = 0.001). Ganglion cell layer, retinal nerve fiber layer, and choroidal thickness are significantly thinner in patients with migraine. The severity of migraine has more significant influence in the thinning of ganglion cell layer and retinal nerve fiber layer, while the duration of the disease affected the choroidal thickness more.

  8. Predicting the threshold of pulse-train electrical stimuli using a stochastic auditory nerve model: the effects of stimulus noise.

    Science.gov (United States)

    Xu, Yifang; Collins, Leslie M

    2004-04-01

    The incorporation of low levels of noise into an electrical stimulus has been shown to improve auditory thresholds in some human subjects (Zeng et al., 2000). In this paper, thresholds for noise-modulated pulse-train stimuli are predicted utilizing a stochastic neural-behavioral model of ensemble fiber responses to bi-phasic stimuli. The neural refractory effect is described using a Markov model for a noise-free pulse-train stimulus and a closed-form solution for the steady-state neural response is provided. For noise-modulated pulse-train stimuli, a recursive method using the conditional probability is utilized to track the neural responses to each successive pulse. A neural spike count rule has been presented for both threshold and intensity discrimination under the assumption that auditory perception occurs via integration over a relatively long time period (Bruce et al., 1999). An alternative approach originates from the hypothesis of the multilook model (Viemeister and Wakefield, 1991), which argues that auditory perception is based on several shorter time integrations and may suggest an NofM model for prediction of pulse-train threshold. This motivates analyzing the neural response to each individual pulse within a pulse train, which is considered to be the brief look. A logarithmic rule is hypothesized for pulse-train threshold. Predictions from the multilook model are shown to match trends in psychophysical data for noise-free stimuli that are not always matched by the long-time integration rule. Theoretical predictions indicate that threshold decreases as noise variance increases. Theoretical models of the neural response to pulse-train stimuli not only reduce calculational overhead but also facilitate utilization of signal detection theory and are easily extended to multichannel psychophysical tasks.

  9. Chronic cuffing of cervical vagus nerve inhibits efferent fiber integrity in rat model

    Science.gov (United States)

    Somann, Jesse P.; Albors, Gabriel O.; Neihouser, Kaitlyn V.; Lu, Kun-Han; Liu, Zhongming; Ward, Matthew P.; Durkes, Abigail; Robinson, J. Paul; Powley, Terry L.; Irazoqui, Pedro P.

    2018-06-01

    Objective. Numerous studies of vagal nerve stimulation (VNS) have been published showing it to be a potential treatment for chronic inflammation and other related diseases and disorders. Studies in recent years have shown that electrical stimulation of the vagal efferent fibers can artificially modulate cytokine levels and reduce systematic inflammation. Most VNS research in the treatment of inflammation have been acute studies on rodent subjects. Our study tested VNS on freely moving animals by stimulating and recording from the cervical vagus with nerve cuff electrodes over an extended period of time. Approach. We used methods of electrical stimulation, retrograde tracing (using Fluorogold) and post necropsy histological analysis of nerve tissue, flow cytometry to measure plasma cytokine levels, and MRI scanning of gastric emptying. This novel combination of methods allowed examination of physiological aspects of VNS previously unexplored. Main results. Through our study of 53 rat subjects, we found that chronically cuffing the left cervical vagus nerve suppressed efferent Fluorogold transport in 43 of 44 animals (36 showed complete suppression). Measured cytokine levels and gastric emptying rates concurrently showed nominal differences between chronically cuffed rats and those tested with similar acute methods. Meanwhile, results of electrophysiological and histological tests of the cuffed nerves revealed them to be otherwise healthy, consistent with previous literature. Significance. We hypothesize that due to these unforeseen and unexplored physiological consequences of the chronically cuffed vagus nerve in a rat, that inflammatory modulation and other vagal effects by VNS may become unreliable in chronic studies. Given our findings, we submit that it would benefit the VNS community to re-examine methods used in previous literature to verify the efficacy of the rat model for chronic VNS studies.

  10. Imaging of the facial nerve

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    Veillon, F. [Service de Radiologie I, Hopital de Hautepierre, 67098 Strasbourg Cedex (France)], E-mail: Francis.Veillon@chru-strasbourg.fr; Ramos-Taboada, L.; Abu-Eid, M. [Service de Radiologie I, Hopital de Hautepierre, 67098 Strasbourg Cedex (France); Charpiot, A. [Service d' ORL, Hopital de Hautepierre, 67098 Strasbourg Cedex (France); Riehm, S. [Service de Radiologie I, Hopital de Hautepierre, 67098 Strasbourg Cedex (France)

    2010-05-15

    The facial nerve is responsible for the motor innervation of the face. It has a visceral motor function (lacrimal, submandibular, sublingual glands and secretion of the nose); it conveys a great part of the taste fibers, participates to the general sensory of the auricle (skin of the concha) and the wall of the external auditory meatus. The facial mimic, production of tears, nasal flow and salivation all depend on the facial nerve. In order to image the facial nerve it is mandatory to be knowledgeable about its normal anatomy including the course of its efferent and afferent fibers and about relevant technical considerations regarding CT and MR to be able to achieve high-resolution images of the nerve.

  11. Adaptation in the auditory system: an overview

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    David ePérez-González

    2014-02-01

    Full Text Available The early stages of the auditory system need to preserve the timing information of sounds in order to extract the basic features of acoustic stimuli. At the same time, different processes of neuronal adaptation occur at several levels to further process the auditory information. For instance, auditory nerve fiber responses already experience adaptation of their firing rates, a type of response that can be found in many other auditory nuclei and may be useful for emphasizing the onset of the stimuli. However, it is at higher levels in the auditory hierarchy where more sophisticated types of neuronal processing take place. For example, stimulus-specific adaptation, where neurons show adaptation to frequent, repetitive stimuli, but maintain their responsiveness to stimuli with different physical characteristics, thus representing a distinct kind of processing that may play a role in change and deviance detection. In the auditory cortex, adaptation takes more elaborate forms, and contributes to the processing of complex sequences, auditory scene analysis and attention. Here we review the multiple types of adaptation that occur in the auditory system, which are part of the pool of resources that the neurons employ to process the auditory scene, and are critical to a proper understanding of the neuronal mechanisms that govern auditory perception.

  12. Structure-function relationships with spectral-domain optical coherence tomography retinal nerve fiber layer and optic nerve head measurements.

    Science.gov (United States)

    Pollet-Villard, Frédéric; Chiquet, Christophe; Romanet, Jean-Paul; Noel, Christian; Aptel, Florent

    2014-05-02

    To evaluate the regional structure-function relationship between visual field sensitivity and retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) measurements using spectral-domain optical coherence tomography (SD-OCT). Prospective cross-sectional study conducted on patients with glaucoma, suspected glaucoma, and healthy subjects. Eyes were tested on Cirrus OCT and standard achromatic perimetry. RNFL thickness of 12 peripapillary 30° sectors, neuroretinal rim thickness extracted from 36 neuroretinal rim scans, and Bruch membrane opening minimum rim width (BMO-MRW)-a recently defined parameter-extracted from 36 neuroretinal rim scans were obtained. Correlations between peripapillary RNFL thickness, neuroretinal rim thickness, all six sectors of BMO-MRW, and visual field sensitivity in the six corresponding areas were evaluated using logarithmic regression analysis. Receiver operating curve areas were calculated for each RNFL, ONH, and macular ganglion cell analysis parameter. We included 142 eyes of 142 subjects. The correlations (r(2)) between RNFL thickness, Cirrus-based neuroretinal rim thickness, BMO-MRW and visual field sensitivity ranged from 0.07 to 0.60, 0.15 to 0.49, and 0.24 to 0.66, respectively. The structure-function correlations were stronger with BMO-MRW than with Cirrus-based neuroretinal rim thickness. The largest areas under the receiver operating curve were seen for rim area (0.926 [95% confidence interval 0.875, 0.977]; P function relationship was significantly stronger with BMO-MRW than other ONH SD-OCT parameters. The best diagnostic capabilities were seen with rim area and average RNFL.

  13. Optical Coherence Tomography in Optic Nerve Hypoplasia: Correlation With Optic Disc Diameter, Nerve Fiber Layer Thickness, and Visual Function.

    Science.gov (United States)

    Kelly, John P; Baran, Francine; Phillips, James O; Weiss, Avery H

    2017-12-15

    The correlation between optic disc diameters (DDs) with average retinal nerve fiber layer thickness (RNFLT) and visual function in children with optic nerve hypoplasia (ONH) having nystagmus is unknown. Data were obtained from a retrospective review of 28 children (mean age: 9.4 years; ±5.1). Optic DD was defined as the maximal horizontal opening of Bruch membrane with spectral optical coherence tomography combined with a confocal laser ophthalmoscope. Average RNFLT was obtained from circumpapillary b-scans. RNFLT was also remeasured at eccentricities that were proportionate with DD to rule out potential sampling artifacts. Visual function was assessed by visual acuity at last follow-up and by visual evoked potentials (VEP) in 11 patients. The eye with the larger DD, which had better visual acuity, was analyzed to exclude potential effects of amblyopia. DD was correlated with average RNFLT (r = 0.61), visual acuity (r = 0.32), and VEPs (r = 0.66). The relationship between RNFLT and DD was as follows: average RNFLT (μm) = 0.074 * DD (μm) - 18.8. RNFLT also correlated with the ratio of horizontal optic DD to macula-disc-margin distance (DD:DM; r = 0.59). RNFLT measured at eccentricities proportionate with DD showed progressive decrease in thickness only for DDs <1,100 μm. All patients with DD <1,000 μm had subnormal visual acuity, whereas those with DD <1,200 μm had subnormal VEPs. DD correlates with average RNFLT and with visual function in children with ONH. Using OCT imaging, DD can be obtained in children with nystagmus and provides objective information.

  14. Peripapillary retinal nerve fiber layer and optic nerve head characteristics in eyes with situs inversus of the optic disc.

    Science.gov (United States)

    Kang, Sunah; Jin, Sunyoung; Roh, Kyu Hwa; Hwang, Young Hoon

    2015-01-01

    This study was performed to investigate the peripapillary retinal nerve fiber layer (RNFL) and optic nerve head (ONH) characteristics, as determined using a spectral-domain optical coherence tomography (OCT), in eyes with situs inversus of the optic disc. The peripapillary RNFL and the ONH were assessed in 12 eyes belonging to 6 subjects with situs inversus of the optic disc (situs inversus group) and 24 eyes in 12 age-matched, sex-matched, and refractive error-matched healthy subjects (control group) by using OCT. The average, quadrant, and clock-hour RNFL thicknesses (clock-hour 9 on the scan represented the temporal side of the optic disc in both eyes), the superior/inferior RNFL peak locations, and ONH characteristics such as disc area, rim area, cup-to-disc ratio, vertical cup-to-disc ratio, and cup volume were obtained. The differences in RNFL and ONH characteristics between the 2 groups were analyzed. The situs inversus group had a thicker RNFL in the clock-hour sectors 3 and 4, a thinner RNFL in the clock-hour sectors 7, 8, and 11, and more nasally located superior and inferior RNFL peak locations than the control group (P≤0.001). The situs inversus group had a smaller cup-to-disc area ratio, smaller vertical cup-to-disc ratio, and a lesser cup volume than the control group (Poptic disc showed different peripapillary RNFL and ONH characteristics from those without this abnormality. These findings should be considered when assessing eyes with situs inversus of the optic disc.

  15. Somatic modulation of spinal reflex bladder activity mediated by nociceptive bladder afferent nerve fibers in cats.

    Science.gov (United States)

    Xiao, Zhiying; Rogers, Marc J; Shen, Bing; Wang, Jicheng; Schwen, Zeyad; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2014-09-15

    The goal of the present study was to determine if supraspinal pathways are necessary for inhibition of bladder reflex activity induced by activation of somatic afferents in the pudendal or tibial nerve. Cats anesthetized with α-chloralose were studied after acute spinal cord transection at the thoracic T9/T10 level. Dilute (0.25%) acetic acid was used to irritate the bladder, activate nociceptive afferent C-fibers, and trigger spinal reflex bladder contractions (amplitude: 19.3 ± 2.9 cmH2O). Hexamethonium (a ganglionic blocker, intravenously) significantly (P reflex bladder contractions to 8.5 ± 1.9 cmH2O. Injection of lidocaine (2%, 1-2 ml) into the sacral spinal cord or transection of the sacral spinal roots and spinal cord further reduced the contraction amplitude to 4.2 ± 1.3 cmH2O. Pudendal nerve stimulation (PNS) at frequencies of 0.5-5 Hz and 40 Hz but not at 10-20 Hz inhibited reflex bladder contractions, whereas tibial nerve stimulation (TNS) failed to inhibit bladder contractions at all tested frequencies (0.5-40 Hz). These results indicate that PNS inhibition of nociceptive afferent C-fiber-mediated spinal reflex bladder contractions can occur at the spinal level in the absence of supraspinal pathways, but TNS inhibition requires supraspinal pathways. In addition, this study shows, for the first time, that after acute spinal cord transection reflex bladder contractions can be triggered by activating nociceptive bladder afferent C-fibers using acetic acid irritation. Understanding the sites of action for PNS or TNS inhibition is important for the clinical application of pudendal or tibial neuromodulation to treat bladder dysfunctions. Copyright © 2014 the American Physiological Society.

  16. A pilot study to evaluate the clinical relevance of endometriosis-associated nerve fibers in peritoneal endometriotic lesions.

    Science.gov (United States)

    Mechsner, Sylvia; Kaiser, Andrea; Kopf, Andreas; Gericke, Christine; Ebert, Andreas; Bartley, Julia

    2009-12-01

    To investigate the clinical relevance of endometriosis-associated nerve fibers in the development of endometriosis-associated symptoms. Prospective nonrandomized study. University hospital endometriosis center. Fifty-one premenopausal patients underwent surgical laparoscopy because of chronic pelvic pain, dysmenorrhea, or for ovarian cysts. Endometriosis was diagnosed in 44 patients. The preoperative and postoperative pain scores were determined using a standardized questionnaire with a visual analogue scale from 1-10. Patients with peritoneal endometriosis were divided into two groups depending on their preoperative pain score: group A with a pain score of at least 3 or more and group B with a pain score of 2 or less. Patients without peritoneal endometriosis were classified as group C and patients without endometriosis were classified as group D. Immunohistochemical analysis of neurofilament and protein gene product 9.5 were used for nerve fiber detection. Occurrence of endometriosis-associated nerve fibers was correlated with the severity of pelvic pain and/or dysmenorrhea. Peritoneal endometriosis-associated nerve fibers were found significantly more frequently in group A than in group B (82.6% vs. 33.3%). The present study suggests that the presence of endometriosis-associated nerve fibers in the peritoneum is important for the development of endometriosis-associated pelvic pain and dysmenorrhea.

  17. MR tractography; Visualization of structure of nerve fiber system from diffusion weighted images with maximum intensity projection method

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    Kinosada, Yasutomi; Okuda, Yasuyuki (Mie Univ., Tsu (Japan). School of Medicine); Ono, Mototsugu (and others)

    1993-02-01

    We developed a new noninvasive technique to visualize the anatomical structure of the nerve fiber system in vivo, and named this technique magnetic resonance (MR) tractography and the acquired image an MR tractogram. MR tractography has two steps. One is to obtain diffusion-weighted images sensitized along axes appropriate for depicting the intended nerve fibers with anisotropic water diffusion MR imaging. The other is to extract the anatomical structure of the nerve fiber system from a series of diffusion-weighted images by the maximum intensity projection method. To examine the clinical usefulness of the proposed technique, many contiguous, thin (3 mm) coronal two-dimensional sections of the brain were acquired sequentially in normal volunteers and selected patients with paralyses, on a 1.5 Tesla MR system (Signa, GE) with an ECG-gated Stejskal-Tanner pulse sequence. The structure of the nerve fiber system of normal volunteers was almost the same as the anatomy. The tractograms of patients with paralyses clearly showed the degeneration of nerve fibers and were correlated with clinical symptoms. MR tractography showed great promise for the study of neuroanatomy and neuroradiology. (author).

  18. Clinical analysis of retinal nerve fiber layer thickness and macular fovea in hyperopia children with anisometropia amblyopia

    Directory of Open Access Journals (Sweden)

    Fei-Fei Li

    2017-10-01

    Full Text Available AIM:To analyze the clinical significance of axial length, diopter and retinal nerve fiber layer thickness in hyperopia children with anisometropia amblyopia. METHODS: From January 2015 to January 2017 in our hospital for treatment, 103 cases, all unilateral, were diagnosed as hyperopia anisometropia amblyopia. The eyes with amblyopia were as experimental group(103 eyes, another normal eye as control group(103 eyes. We took the detection with axial length, refraction, foveal thickness, corrected visual acuity, diopter and the average thickness of retinal nerve fiber layer. RESULTS: Differences in axial length and diopter and corrected visual acuity were statistically significant between the two groups(PP>0.05. There was statistical significance difference on the foveal thickness(PP>0.05. The positive correlation between diopter with nerve fiber layer thickness of foveal and around the optic disc were no statistically significant difference(P>0.05. CONCLUSION: Retinal thickness of the fovea in the eye with hyperopic anisometropia amblyopia were thicker than those in normal eyes; the nerve fiber layer of around the optic disc was not significantly different between the amblyopic eyes and contralateral eyes. The refraction and axial length had no significant correlation with optic nerve fiber layer and macular foveal thickness.

  19. [Progression of nerve fiber layer defects in retrobulbar optic neuritis by the macular ganglion cell complex].

    Science.gov (United States)

    Hong, D; Bosc, C; Chiambaretta, F

    2017-11-01

    Recent studies with SD OCT had shown early axonal damage to the macular ganglion cell complex (which consists of the three innermost layers of the retina: Inner Plexiform Layer [IPL], Ganglion Cell Layer [GCL], Retinal Nerve Fibre layer [RNFL]) in optic nerve pathology. Retrobulbar optic neuritis (RBON), occurring frequently in demyelinating diseases, leads to atrophy of the optic nerve fibers at the level of the ganglion cell axons, previously described in the literature. The goal of this study is to evaluate the progression of optic nerve fiber defects and macular ganglion cell complex defects with the SPECTRALIS OCT via a reproducible method by calculating a mean thickness in each quadrant after an episode of retrobulbar optic neuritis. This is a prospective monocentric observational study including 8 patients at the Clermont-Ferrand university medical center. All patients underwent ocular examination with macular and disc OCT analysis and a Goldmann visual field at the time of inclusion (onset or recurrence of RBON), at 3 months and at 6 months. Patients were 40-years-old on average at the time of inclusion. After 6 months of follow-up, there was progression of the atrophy of the macular ganglion cell complex in the affected eye on (11.5% or 11μm) predominantly inferonasally (13.9% or 16μm) and superonasally (12.9% or 14μm) while the other eye remained stable. The decrease in thickness occurred mainly in the most internal 3 layers of the retina. On average, the loss in thickness of the peripapillary RNFL was predominantly inferotemporal (24.9% or 39μm) and superotemporal (21.8% or 28μm). In 3 months of progression, the loss of optic nerve fibers is already seen on macular and disc OCT after an episode of RBON, especially in inferior quadrants in spite of the improvement in the Goldmann visual field and visual acuity. Segmentation by quadrant was used here to compare the progression of the defect by region compared to the fovea in a global and reproducible

  20. Optic Nerve Imaging

    Science.gov (United States)

    ... News About Us Donate In This Section Optic Nerve Imaging email Send this article to a friend ... measurements of nerve fiber damage (or loss). The Nerve Fiber Analyzer (GDx) uses laser light to measure ...

  1. BDNF Increases Survival and Neuronal Differentiation of Human Neural Precursor Cells Cotransplanted with a Nanofiber Gel to the Auditory Nerve in a Rat Model of Neuronal Damage

    Directory of Open Access Journals (Sweden)

    Yu Jiao

    2014-01-01

    Full Text Available Objectives. To study possible nerve regeneration of a damaged auditory nerve by the use of stem cell transplantation. Methods. We transplanted HNPCs to the rat AN trunk by the internal auditory meatus (IAM. Furthermore, we studied if addition of BDNF affects survival and phenotypic differentiation of the grafted HNPCs. A bioactive nanofiber gel (PA gel, in selected groups mixed with BDNF, was applied close to the implanted cells. Before transplantation, all rats had been deafened by a round window niche application of β-bungarotoxin. This neurotoxin causes a selective toxic destruction of the AN while keeping the hair cells intact. Results. Overall, HNPCs survived well for up to six weeks in all groups. However, transplants receiving the BDNF-containing PA gel demonstrated significantly higher numbers of HNPCs and neuronal differentiation. At six weeks, a majority of the HNPCs had migrated into the brain stem and differentiated. Differentiated human cells as well as neurites were observed in the vicinity of the cochlear nucleus. Conclusion. Our results indicate that human neural precursor cells (HNPC integration with host tissue benefits from additional brain derived neurotrophic factor (BDNF treatment and that these cells appear to be good candidates for further regenerative studies on the auditory nerve (AN.

  2. Evidence for a intimate relationship between mast cells and nerve fibers in the tongue of the frog, Rana esculenta

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    Chieffi Baccari, Gabriella; Minucci, Sergio [Naples, II Univ. (Italy). Dipt. di Fisiologia Umana e Funzioni Biologiche Integrate `Filippo Bottazzi`

    1997-12-31

    Morphological and ultrastructural association of mast cells and nerve fibers were studied in the tongue of the frog Rana esculenta. The number of mast cells in the tongue (253 {+-} 45 / mm{sup 2}) is far the highest of the frog tissue as far as people know. They are distributed throughout the connective tissue among the muscular fibers, near arterioles and venules but predominantly in close association and within the nerves. They are often embedded in the endoneurium within a nerve bundle near to myelinic or unmyelinic fibers and in membrane-to-membrane contact with axonlike processes. Just for the richness of mast cells, the tongue of the frog could represent an useful model to study the relationship between these cells and the peripheral nervous system.

  3. Evidence for a intimate relationship between mast cells and nerve fibers in the tongue of the frog, Rana esculenta

    Energy Technology Data Exchange (ETDEWEB)

    Chieffi Baccari, Gabriella; Minucci, Sergio [Naples, II Univ. (Italy). Dipt. di Fisiologia Umana e Funzioni Biologiche Integrate ` Filippo Bottazzi`

    1998-12-31

    Morphological and ultrastructural association of mast cells and nerve fibers were studied in the tongue of the frog Rana esculenta. The number of mast cells in the tongue (253 {+-} 45 / mm{sup 2}) is far the highest of the frog tissue as far as people know. They are distributed throughout the connective tissue among the muscular fibers, near arterioles and venules but predominantly in close association and within the nerves. They are often embedded in the endoneurium within a nerve bundle near to myelinic or unmyelinic fibers and in membrane-to-membrane contact with axonlike processes. Just for the richness of mast cells, the tongue of the frog could represent an useful model to study the relationship between these cells and the peripheral nervous system.

  4. Development and evaluation of spatial point process models for epidermal nerve fibers.

    Science.gov (United States)

    Olsbo, Viktor; Myllymäki, Mari; Waller, Lance A; Särkkä, Aila

    2013-06-01

    We propose two spatial point process models for the spatial structure of epidermal nerve fibers (ENFs) across human skin. The models derive from two point processes, Φb and Φe, describing the locations of the base and end points of the fibers. Each point of Φe (the end point process) is connected to a unique point in Φb (the base point process). In the first model, both Φe and Φb are Poisson processes, yielding a null model of uniform coverage of the skin by end points and general baseline results and reference values for moments of key physiologic indicators. The second model provides a mechanistic model to generate end points for each base, and we model the branching structure more directly by defining Φe as a cluster process conditioned on the realization of Φb as its parent points. In both cases, we derive distributional properties for observable quantities of direct interest to neurologists such as the number of fibers per base, and the direction and range of fibers on the skin. We contrast both models by fitting them to data from skin blister biopsy images of ENFs and provide inference regarding physiological properties of ENFs. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Modeling the time-varying and level-dependent effects of the medial olivocochlear reflex in auditory nerve responses.

    Science.gov (United States)

    Smalt, Christopher J; Heinz, Michael G; Strickland, Elizabeth A

    2014-04-01

    The medial olivocochlear reflex (MOCR) has been hypothesized to provide benefit for listening in noisy environments. This advantage can be attributed to a feedback mechanism that suppresses auditory nerve (AN) firing in continuous background noise, resulting in increased sensitivity to a tone or speech. MOC neurons synapse on outer hair cells (OHCs), and their activity effectively reduces cochlear gain. The computational model developed in this study implements the time-varying, characteristic frequency (CF) and level-dependent effects of the MOCR within the framework of a well-established model for normal and hearing-impaired AN responses. A second-order linear system was used to model the time-course of the MOCR using physiological data in humans. The stimulus-level-dependent parameters of the efferent pathway were estimated by fitting AN sensitivity derived from responses in decerebrate cats using a tone-in-noise paradigm. The resulting model uses a binaural, time-varying, CF-dependent, level-dependent OHC gain reduction for both ipsilateral and contralateral stimuli that improves detection of a tone in noise, similarly to recorded AN responses. The MOCR may be important for speech recognition in continuous background noise as well as for protection from acoustic trauma. Further study of this model and its efferent feedback loop may improve our understanding of the effects of sensorineural hearing loss in noisy situations, a condition in which hearing aids currently struggle to restore normal speech perception.

  6. Evaluating Glaucomatous Retinal Nerve Fiber Damage by GDx VCC Polarimetry in Taiwan Chinese Population

    Science.gov (United States)

    Chen, Hsin-Yi; Huang, Mei-Ling; Huang, Wei-Cheng

    2010-01-01

    Purpose To study the capability of scanning laser polarimetry with variable corneal compensation (GDx VCC) to detect differences in retinal nerve fiber layer thickness between normal and glaucomatous eyes in a Taiwan Chinese population. Methods This study included 44 normal eyes and 107 glaucomatous eyes. The glaucomatous eyes were divided into three subgroups on the basis of its visual field defects (early, moderate, severe). Each subject underwent a GDx-VCC exam and visual field testing. The area under the receiver-operating characteristic curve (AROC) of each relevant parameter was used to differentiate normal from each glaucoma subgroup, respectively. The correlation between visual field index and each parameter was evaluated for the eyes in the glaucoma group. Results For normal vs. early glaucoma, the parameter with the best AROC was Nerve fiber indicator (NFI) (0.942). For normal vs. moderate glaucoma, the parameter showing the best AROC was NFI (0.985). For normal vs. severe glaucoma, the parameter that had the best AROC was NFI (1.000). For early vs. moderate glaucoma, the parameter with the best AROC was NFI (0.732). For moderate vs. severe, the parameter showing the best AROC was temporal-superior-nasal-inferior-temporal average (0.652). For early vs. severe, the parameter with the best AROC was NFI (0.852). Conclusions GDx-VCC-measured parameters may serve as a useful tool to distinguish normal from glaucomatous eyes; in particular, NFI turned out to be the best discriminating parameter.

  7. Evoked bioelectrical activity of efferent fibers of the sciatic nerve of white rats in experimental menopause

    Directory of Open Access Journals (Sweden)

    Rodinsky A.G.

    2016-03-01

    Full Text Available The aim of our work was analysis of the bioelectrical activity of efferent fibers of the sciatic nerve in experimental menopause condition. Experiments were performed on 25 female white rats, divided into experimental and control groups. Menopause was modeled by total ovariohysterectomy. In 120 days after modeling we had recorded evoked action potentials of fibers of isolated ventral root L5 induced by stimulation of sciatic nerve with rectangular pulses. Threshold, chronaxia, latency, amplitude and duration of the action potential (AP were analysed. Refractory phenomenon was investigated by applying paired stimuli at intervals of 2 to 20 ms. In the context of long-term hypoestrogenemy threshold of AP appearance was 55,32±7,69%, chronaxy – 115,09±2,67%, latent period – 112,62±1,74% as compared with the control animals (p<0.01. In conditions of paired stimuli applying the amplitude of response to the testing stimulus in animals with ovariohysterectomy at intervals 3 and 4 ms was 61,25±36,45% and 53,48±18,64% (p<0.05 respectively.

  8. The Effects of Smoking on Anterior Segment Parameters, Retinal Nerve Fiber Layer, and Pupillary Functions

    Directory of Open Access Journals (Sweden)

    Bengü Ekinci Köktekir

    2014-01-01

    Full Text Available Objectives: To evaluate the alterations in the anterior segment parameters, retinal nerve fiber layer, and pupillary functions in smokers. Materials and Methods: In this case-control study, 45 eyes of 45 smokers and 45 eyes of 45 non-smoker control subjects were evaluated. All patients underwent measurement of anterior segment parameters with optical low coherence reflectometry (OLCR, mesopic and photopic pupillary diameter with an aberrometer device, retinal nerve fiber layer thickness with optical coherence tomography, and dry-eye assessment with Schirmer’s test. The results were compared with independent t-test by SPSS 16.0 Inc., and a p-value lower than 0.05 was determined as significant. Results: There was a significant difference between both groups in terms of mesopic pupil diameters that were measured with both OLCR and aberrometer device (p=0.03 and 0.02, respectively. Schirmer scores were also significantly decreased in smokers (p=0.001. The other measured parameters demonstrated no difference between smokers and non-smokers (p>0.05 for all. Conclusion: Smoking may affect pupillary functions, especially the mesopic pupillary diameter, and may cause a deficiency in pupil response under dark circumstances. (Turk J Ophthalmol 2014; 44: 11-4

  9. Biosynthesis of fatty acids and cholesterol in squid giant nerve fiber

    International Nuclear Information System (INIS)

    Tanaka, T.; Kishimoto, Y.; Gould, R.M.

    1987-01-01

    The giant nerve fiber of squid 3 (loligo pealel) was incubated with [1- 14 C]acetate and ( 3 H)myristate. Fifty-five percent of the radioactivity incorporated from acetate was recovered in fatty acid methyl esters (FAME). The FAME was fractionated by AgNO 3 -impregnated TLC plate; and 52%, 31%, 0.3%, 5%, and 11% of the radioactivity was recovered in spots associated with saturated, monoenes, dienes, trienes, and polyenes, respectively. The saturated FAME was further fractionated by reverse-phase HPLC; and 4, 47, 1, and 48% of the radioactivity was recovered in 14:0, 16:0, 17:0, and 18:0, respectively. Most radioactivity from polyenes migrated to the spot containing saturated FAME, after catalytical hydrogenation. Cholesterol was isolated and converted to dibromoderivative and the derivative was recrystallized. No radioactivity was found in purified dibromocholesterol. Nearly all radioactivity from myristate-labeled tissue was recovered in saturated FAME. Reverse-phase HPLC showed that 71%, 25%, and 3% of radioactivity was associated with 14:0, 16:0, and 18:0, respectively. These results indicate that the squid giant nerve fibers can synthesize fatty acids by de novo and also by chain elongation and desaturation, though at a slower rate

  10. Whole mount preparation of the adult Drosophila ventral nerve cord for giant fiber dye injection.

    Science.gov (United States)

    Boerner, Jana; Godenschwege, Tanja A

    2011-06-04

    To analyze the axonal and dendritic morphology of neurons, it is essential to obtain accurate labeling of neuronal structures. Preparing well labeled samples with little to no tissue damage enables us to analyze cell morphology and to compare individual samples to each other, hence allowing the identification of mutant anomalies. In the demonstrated dissection method the nervous system remains mostly inside the adult fly. Through a dorsal incision, the abdomen and thorax are opened and most of the internal organs are removed. Only the dorsal side of the ventral nerve cord (VNC) and the cervical connective (CvC) containing the big axons of the giant fibers (GFs) are exposed, while the brain containing the GF cell body and dendrites remains in the intact head. In this preparation most nerves of the VNC should remain attached to their muscles. Following the dissection, the intracellular filling of the giant fiber (GF) with a fluorescent dye is demonstrated. In the CvC the GF axons are located at the dorsal surface and thus can be easily visualized under a microscope with differential interference contrast (DIC) optics. This allows the injection of the GF axons with dye at this site to label the entire GF including the axons and their terminals in the VNC. This method results in reliable and strong staining of the GFs allowing the neurons to be imaged immediately after filling with an epifluorescent microscope. Alternatively, the fluorescent signal can be enhanced using standard immunohistochemistry procedures suitable for high resolution confocal microscopy.

  11. Retinal Nerve Fiber Layer Segmentation on FD-OCT Scans of Normal Subjects and Glaucoma Patients.

    Science.gov (United States)

    Mayer, Markus A; Hornegger, Joachim; Mardin, Christian Y; Tornow, Ralf P

    2010-11-08

    Automated measurements of the retinal nerve fiber layer thickness on circular OCT B-Scans provide physicians additional parameters for glaucoma diagnosis. We propose a novel retinal nerve fiber layer segmentation algorithm for frequency domain data that can be applied on scans from both normal healthy subjects, as well as glaucoma patients, using the same set of parameters. In addition, the algorithm remains almost unaffected by image quality. The main part of the segmentation process is based on the minimization of an energy function consisting of gradient and local smoothing terms. A quantitative evaluation comparing the automated segmentation results to manually corrected segmentations from three reviewers is performed. A total of 72 scans from glaucoma patients and 132 scans from normal subjects, all from different persons, composed the database for the evaluation of the segmentation algorithm. A mean absolute error per A-Scan of 2.9 µm was achieved on glaucomatous eyes, and 3.6 µm on healthy eyes. The mean absolute segmentation error over all A-Scans lies below 10 µm on 95.1% of the images. Thus our approach provides a reliable tool for extracting diagnostic relevant parameters from OCT B-Scans for glaucoma diagnosis.

  12. An Exceptional Case of Intraparotid Plexiform Neurofibroma Originating from Autonomic Fibers of the Auriculotemporal Nerve

    Directory of Open Access Journals (Sweden)

    Sarantis Blioskas

    2017-01-01

    Full Text Available Plexiform neurofibromas are benign tumors that tend to occur in patients suffering from neurofibromatosis type 1 (NF-1. This report addresses a rare case where the tumor affected the parotid gland, deriving almost exclusively from the peripheral portion of the facial nerve. A 6-year-old male was referred to us complaining about a gradually enlarging swelling over the right parotid area. Imaging localized the lesion to the superficial lobe of the parotid gland, suggesting a neurofibroma. Cosmetic disfigurement and a functional deficit led us to perform complete surgical resection. Meticulous surgical dissection as well as auriculotemporal nerve origin made complete extirpation possible with almost zero morbidity and ensured alleviation of both aesthetic impairment and pain. This is the first case of an intraparotid PN in a pediatric NF-1 patient, which originated from branches of the auriculotemporal nerve and particularly from fibers of the autonomic nervous system. Radical surgical excision was decided according to established decision-making algorithms.

  13. Nano-scale Biophysical and Structural Investigations on Intact and Neuropathic Nerve Fibers by Simultaneous Combination of Atomic Force and Confocal Microscopy

    Directory of Open Access Journals (Sweden)

    Gonzalo Rosso

    2017-08-01

    Full Text Available The links between neuropathies of the peripheral nervous system (PNS, including Charcot-Marie-Tooth1A and hereditary neuropathy with liability to pressure palsies, and impaired biomechanical and structural integrity of PNS nerves remain poorly understood despite the medical urgency. Here, we present a protocol describing simultaneous structural and biomechanical integrity investigations on isolated nerve fibers, the building blocks of nerves. Nerve fibers are prepared from nerves harvested from wild-type and exemplary PNS neuropathy mouse models. The basic principle of the designed experimental approach is based on the simultaneous combination of atomic force microscopy (AFM and confocal microscopy. AFM is used to visualize the surface structure of nerve fibers at nano-scale resolution. The simultaneous combination of AFM and confocal microscopy is used to perform biomechanical, structural, and functional integrity measurements at nano- to micro-scale. Isolation of sciatic nerves and subsequent teasing of nerve fibers take ~45 min. Teased fibers can be maintained at 37°C in a culture medium and kept viable for up to 6 h allowing considerable time for all measurements which require 3–4 h. The approach is designed to be widely applicable for nerve fibers from mice of any PNS neuropathy. It can be extended to human nerve biopsies.

  14. A hardware model of the auditory periphery to transduce acoustic signals into neural activity

    Directory of Open Access Journals (Sweden)

    Takashi eTateno

    2013-11-01

    Full Text Available To improve the performance of cochlear implants, we have integrated a microdevice into a model of the auditory periphery with the goal of creating a microprocessor. We constructed an artificial peripheral auditory system using a hybrid model in which polyvinylidene difluoride was used as a piezoelectric sensor to convert mechanical stimuli into electric signals. To produce frequency selectivity, the slit on a stainless steel base plate was designed such that the local resonance frequency of the membrane over the slit reflected the transfer function. In the acoustic sensor, electric signals were generated based on the piezoelectric effect from local stress in the membrane. The electrodes on the resonating plate produced relatively large electric output signals. The signals were fed into a computer model that mimicked some functions of inner hair cells, inner hair cell–auditory nerve synapses, and auditory nerve fibers. In general, the responses of the model to pure-tone burst and complex stimuli accurately represented the discharge rates of high-spontaneous-rate auditory nerve fibers across a range of frequencies greater than 1 kHz and middle to high sound pressure levels. Thus, the model provides a tool to understand information processing in the peripheral auditory system and a basic design for connecting artificial acoustic sensors to the peripheral auditory nervous system. Finally, we discuss the need for stimulus control with an appropriate model of the auditory periphery based on auditory brainstem responses that were electrically evoked by different temporal pulse patterns with the same pulse number.

  15. Prevalence of Split Nerve Fiber Layer Bundles in Healthy People Imaged with Spectral Domain Optical Coherence Tomography

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    Sirel Gür Güngör

    2016-12-01

    Full Text Available Objectives: The presence of retinal nerve fiber layer (RNFL split bundles was recently described in normal eyes scanned using scanning laser polarimetry and by histologic studies. Split bundles may resemble RNFL loss in healthy eyes. The aim of our study was to determine the prevalence of nerve fiber layer split bundles in healthy people. Materials and Methods: We imaged 718 eyes of 359 healthy persons with the spectral domain optical coherence tomography in this cross-sectional study. All eyes had intraocular pressure of 21 mmHg or less, normal appearance of the optic nerve head, and normal visual fields (Humphrey Field Analyzer 24-2 full threshold program. In our study, a bundle was defined as ‘split’ when there is localized defect not resembling a wedge defect in the RNFL deviation map with a symmetrically divided RNFL appearance on the RNFL thickness map. The classification was performed by two independent observers who used an identical set of reference examples to standardize the classification. Results: Inter-observer consensus was reached in all cases. Bilateral superior split bundles were seen in 19 cases (5.29% and unilateral superior split was observed in 15 cases (4.16%. In 325 cases (90.52% there was no split bundle. Conclusion: Split nerve fiber layer bundles, in contrast to single nerve fiber layer bundles, are not common findings in healthy eyes. In eyes with normal optic disc appearance, especially when a superior RNFL defect is observed in RNFL deviation map, the RNLF thickness map and graphs should also be examined for split nerve fiber layer bundles.

  16. MR neurography of the median nerve at 3.0 T: Optimization of diffusion tensor imaging and fiber tractography

    International Nuclear Information System (INIS)

    Guggenberger, Roman; Eppenberger, Patrick; Markovic, Daniel; Nanz, Daniel; Chhabra, Avneesh; Pruessmann, Klaas P.; Andreisek, Gustav

    2012-01-01

    Objectives: The purpose of this study was to systematically assess the optimal b-value and reconstruction parameters for DTI and fiber tractography of the median nerve at 3.0 T. Methods: Local ethical board approved study with 45 healthy volunteers (15 men, 30 women; mean age, 41 ± 3.4 years) who underwent DTI of the right wrist at 3.0 T. A single-shot echo-planar-imaging sequence (TR/TE 10123/40 ms) was acquired at four different b-values (800, 1000, 1200, and 1400 s/mm 2 ). Two independent readers performed post processing and fiber-tractography. Fractional anisotropy (FA) maps were calculated. Fiber tracts of the median nerve were generated using four different algorithms containing different FA thresholds and different angulation tolerances. Data were evaluated quantitatively and qualitatively. Results: Tracking algorithms using a minimum FA threshold of 0.2 and a maximum angulation of 10° were significantly better than other algorithms. Fiber tractography generated significantly longer fibers in DTI acquisitions with higher b-values (1200 and 1400 s/mm 2 versus 800 s/mm 2 ; p 2 (p 2 for DTI of the median nerve at 3.0 T. Optimal reconstruction parameters for fiber tractography should encompass a minimum FA threshold of 0.2 and a maximum angulation tolerance of 10.

  17. Changes in retinal nerve fiber layer thickness after spinal surgery in the prone position: a prospective study

    OpenAIRE

    Gencer, Baran; Cosar, Murat; Tufan, Hasan Ali; Kara, Selcuk; Arikan, Sedat; Akman, Tarik; Kiraz, Hasan Ali; Comez, Arzu Taskiran; Hanci, Volkan

    2015-01-01

    BACKGROUND AND OBJECTIVES: Changes in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. ...

  18. Loss of temporal peripapillary retinal nerve fibers in prediabetes or type 2 diabetes without diabetic retinopathy: The Maastricht Study

    NARCIS (Netherlands)

    de Clerck, E.E.B.; Schouten, J.S.A.G.; Berendschot, T.T.J.M.; Beckers, H.J.M.; Schaper, N.C.; Schram, M.T.; Stehouwer, C.D.A.; Webers, C.A.B.

    Purpose: The purpose of this study was to assess thinning of the peripapillary retinal nerve fiber layer (RNFL) in prediabetes or type 2 diabetes without diabetic retinopathy (DM2 w/o DRP) compared with that in individuals with normal glucose metabolism (NGM). Methods: We measured sectoral and mean

  19. Optical coherence tomography in retinitis pigmentosa: reproducibility and capacity to detect macular and retinal nerve fiber layer thickness alterations.

    Science.gov (United States)

    Garcia-Martin, Elena; Pinilla, Isabel; Sancho, Eva; Almarcegui, Carmen; Dolz, Isabel; Rodriguez-Mena, Diego; Fuertes, Isabel; Cuenca, Nicolas

    2012-09-01

    To evaluate the ability of time-domain and Fourier-domain optical coherence tomographies (OCTs) to detect macular and retinal nerve fiber layer atrophies in retinitis pigmentosa (RP). To test the intrasession reproducibility using three OCT instruments (Stratus, Cirrus, and Spectralis). Eighty eyes of 80 subjects (40 RP patients and 40 healthy subjects) underwent a visual field examination, together with 3 macular scans and 3 optic disk evaluations by the same experienced examiner using 3 OCT instruments. Differences between healthy and RP eyes were compared. The relationship between measurements with each OCT instrument was evaluated. Repeatability was studied by intraclass correlation coefficients and coefficients of variation. Macular and retinal nerve fiber layer atrophies were detected in RP patients for all OCT parameters. Macular and retinal nerve fiber layer thicknesses, as determined by the different OCTs, were correlated but significantly different (P < 0.05). Reproducibility was moderately high using Stratus, good using Cirrus and Spectralis, and excellent using the Tru-track technology of Spectralis. In RP eyes, measurements showed higher variability compared with healthy eyes. Differences in thickness measurements existed between OCT instruments, despite there being a high degree of correlation. Fourier-domain OCT can be considered a valid and repeatability technique to detect retinal nerve fiber layer atrophy in RP patients.

  20. Taste bud-derived BDNF maintains innervation of a subset of TrkB-expressing gustatory nerve fibers.

    Science.gov (United States)

    Tang, Tao; Rios-Pilier, Jennifer; Krimm, Robin

    2017-07-01

    Taste receptor cells transduce different types of taste stimuli and transmit this information to gustatory neurons that carry it to the brain. Taste receptor cells turn over continuously in adulthood, requiring constant new innervation from nerve fibers. Therefore, the maintenance of innervation to taste buds is an active process mediated by many factors, including brain-derived neurotrophic factor (BDNF). Specifically, 40% of taste bud innervation is lost when Bdnf is removed during adulthood. Here we speculated that not all gustatory nerve fibers express the BDNF receptor, TrkB, resulting in subsets of neurons that vary in their response to BDNF. However, it is also possible that the partial loss of innervation occurred because the Bdnf gene was not effectively removed. To test these possibilities, we first determined that not all gustatory nerve fibers express the TrkB receptor in adult mice. We then verified the efficiency of Bdnf removal specifically in taste buds of K14-CreER:Bdnf mice and found that Bdnf expression was reduced to 1%, indicating efficient Bdnf gene recombination. BDNF removal resulted in a 55% loss of TrkB-expressing nerve fibers, which was greater than the loss of P2X3-positive fibers (39%), likely because taste buds were innervated by P2X3+/TrkB- fibers that were unaffected by BDNF removal. We conclude that gustatory innervation consists of both TrkB-positive and TrkB-negative taste fibers and that BDNF is specifically important for maintaining TrkB-positive innervation to taste buds. In addition, although taste bud size was not affected by inducible Bdnf removal, the expression of the γ subunit of the ENaC channel was reduced. So, BDNF may regulate expression of some molecular components of taste transduction pathways. Copyright © 2017. Published by Elsevier Inc.

  1. Myelination and nodal formation of regenerated peripheral nerve fibers following transplantation of acutely prepared olfactory ensheathing cells

    Science.gov (United States)

    Dombrowski, Mary A.; Sasaki, Masanori; Lankford, Karen L.; Kocsis, Jeffery D.; Radtke, Christine

    2009-01-01

    Transplantation of olfactory ensheathing cells (OECs) into injured spinal cord results in improved functional outcome. Mechanisms suggested to account for this functional improvement include axonal regeneration, remyelination and neuroprotection. OECs transplanted into transected peripheral nerve have been shown to modify peripheral axonal regeneration and functional outcome. However, little is known of the detailed integration of OECs at the transplantation site in peripheral nerve. To address this issue cells populations enriched in OECs were isolated from the olfactory bulbs of adult green fluorescent protein (GFP)-expressing transgenic rats and transplanted into a sciatic nerve crush lesion which transects all axons. Five weeks to six months after transplantation the nerves were studied histologically. GFP-expressing OECs survived in the lesion and distributed longitudinally across the lesion zone. The internodal regions of individual teased fibers distal to the transection site were characterized by GFP expression in the cytoplasmic and nuclear compartments of cells surrounding the axons. Immuno-electron microscopy for GFP indicated that the transplanted OECs formed peripheral type myelin. Immunostaining for sodium channel and Caspr revealed a high density of Nav1.6 at the newly formed nodes of Ranvier which were flanked by paranodal Caspr staining. These results indicate that transplanted OECs extensively integrate into transected peripheral nerve and form myelin on regenerated peripheral nerve fibers, and that nodes of Ranvier of these axons display proper sodium channel organization. PMID:17112480

  2. The application of fuzzy-based methods to central nerve fiber imaging

    DEFF Research Database (Denmark)

    Axer, Hubertus; Jantzen, Jan; Keyserlingk, Diedrich Graf v.

    2003-01-01

    This paper discusses the potential of fuzzy logic methods within medical imaging. Technical advances have produced imaging techniques that can visualize structures and their functions in the living human body. The interpretation of these images plays a prominent role in diagnostic and therapeutic...... decisions, so physicians must deal with a variety of image processing methods and their applications.This paper describes three different sources of medical imagery that allow the visualization of nerve fibers in the human brain: (1) an algorithm for automatic segmentation of some parts of the thalamus....... Fuzzy logic methods were applied to analyze these pictures from low- to high-level image processing. The solutions presented here are motivated by problems of routine neuroanatomic research demonstrating fuzzy-based methods to be valuable tools in medical image processing....

  3. Study of the Peripheral Nerve Fibers Myelin Structure Changes during Activation of Schwann Cell Acetylcholine Receptors.

    Directory of Open Access Journals (Sweden)

    Ekaterina E Verdiyan

    Full Text Available In the present paper we consider a new type of mechanism by which neurotransmitter acetylcholine (ACh regulates the properties of peripheral nerve fibers myelin. Our data show the importance of the relationship between the changes in the number of Schwann cell (SC acetylcholine receptors (AChRs and the axon excitation (different intervals between action potentials (APs. Using Raman spectroscopy, an effect of activation of SC AChRs on the myelin membrane fluidity was investigated. It was found, that ACh stimulates an increase in lipid ordering degree of the myelin lipids, thus providing evidence for specific role of the "axon-SC" interactions at the axon excitation. It was proposed, that during the axon excitation, the SC membrane K+- depolarization and the Ca2+-influx led to phospholipase activation or exocytosis of intracellular membrane vesicles and myelin structure reorganization.

  4. Retinal nerve fiber layer measurements by scanning laser polarimetry with enhanced corneal compensation in healthy subjects.

    Science.gov (United States)

    Rao, Harsha L; Venkatesh, Chirravuri R; Vidyasagar, Kelli; Yadav, Ravi K; Addepalli, Uday K; Jude, Aarthi; Senthil, Sirisha; Garudadri, Chandra S

    2014-12-01

    To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects. In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements. One randomly selected eye of 48 subjects from the cohort underwent 3 serial scans during the same session to determine the repeatability. Age significantly influenced all RNFL measurements. RNFL measurements decreased by 1 µm for every decade increase in age. TSS affected the overall average RNFL measurement (β=-0.62, P=0.003), whereas residual anterior segment retardance affected the superior quadrant measurement (β=1.14, P=0.01). Axial length and corneal birefringence measurements did not influence RNFL measurements. Repeatability, as assessed by the coefficient of variation, ranged between 1.7% for the overall average RNFL measurement and 11.4% for th nerve fiber indicator. Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

  5. Scanning Laser Polarimetry and Optical Coherence Tomography for Detection of Retinal Nerve Fiber Layer Defects

    Science.gov (United States)

    Oh, Jong-Hyun

    2009-01-01

    Purpose To compare the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and Stratus optical coherence tomography (OCT) to detect photographic retinal nerve fiber layer (RNFL) defects. Methods This retrospective cross-sectional study included 45 eyes of 45 consecutive glaucoma patients with RNFL defects in red-free fundus photographs. The superior and inferior temporal quadrants in each eye were included for data analysis separately. The location and presence of RNFL defects seen in red-free fundus photographs were compared with those seen in GDx-VCC deviation maps and OCT RNFL analysis maps for each quadrant. Results Of the 90 quadrants (45 eyes), 31 (34%) had no apparent RNFL defects, 29 (32%) had focal RNFL defects, and 30 (33%) had diffuse RNFL defects in red-free fundus photographs. The highest agreement between GDx-VCC and red-free photography was 73% when we defined GDx-VCC RNFL defects as a cluster of three or more color-coded squares (p<5%) along the traveling line of the retinal nerve fiber in the GDx-VCC deviation map (kappa value, 0.388; 95% confidence interval (CI), 0.195 to 0.582). The highest agreement between OCT and red-free photography was 85% (kappa value, 0.666; 95% CI, 0.506 to 0.825) when a value of 5% outside the normal limit for the OCT analysis map was used as a cut-off value for OCT RNFL defects. Conclusions According to the kappa values, the agreement between GDx-VCC deviation maps and red-free photography was poor, whereas the agreement between OCT analysis maps and red-free photography was good. PMID:19794943

  6. Long-term retinal nerve fiber layer changes following nonarteritic anterior ischemic optic neuropathy

    Directory of Open Access Journals (Sweden)

    Dotan G

    2013-04-01

    Full Text Available Gad Dotan,1 Michaella Goldstein,1 Anat Kesler,1 Barry Skarf21Department of Ophthalmology, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 2Eye Care Services, Henry Ford Hospital, Detroit, MI, USABackground: In cases of nonarteritic anterior ischemic optic neuropathy (NAION, retinal nerve fiber layer (RNFL thickness changes have been described during the first 12 months following the acute event. The purpose of this study was to report on the long-term RNFL changes in these eyes beyond the first year following onset of NAION.Methods: Fourteen eyes of 13 patients with NAION were analyzed in this retrospective observational case series study. Uninvolved eyes served as controls. All patients underwent a complete neuro-ophthalmological examination and repeat measurements of peripapillary RNFL thickness using Stratus optical coherence tomography.Results: On optical coherence tomography scan performed on average 6 months following onset of NAION, the mean global RNFL thickness (59.8 ± 11.8 μm was significantly thinner (P < 0.001 compared with uninvolved eyes (95.1 ± 13.9 μm. In a second optical coherence tomography scan performed on average 13 (range 12–23 months later, the mean global RNFL thickness (58.9 ± 6.5 μm was not significantly different (P = 0.702 from the first scan.Conclusion: There appears to be no further RNFL loss beyond the first 6 months following an acute event of NAION.Keywords: optical coherence tomography, retinal nerve fiber layer, nonartertic anterior ischemic optic neuropathy

  7. In-vivo imaging of retinal nerve fiber layer vasculature: imaging – histology comparison

    Directory of Open Access Journals (Sweden)

    Libby Richard T

    2009-08-01

    Full Text Available Abstract Background Although it has been suggested that alterations of nerve fiber layer vasculature may be involved in the etiology of eye diseases, including glaucoma, it has not been possible to examine this vasculature in-vivo. This report describes a novel imaging method, fluorescence adaptive optics (FAO scanning laser ophthalmoscopy (SLO, that makes possible for the first time in-vivo imaging of this vasculature in the living macaque, comparing in-vivo and ex-vivo imaging of this vascular bed. Methods We injected sodium fluorescein intravenously in two macaque monkeys while imaging the retina with an FAO-SLO. An argon laser provided the 488 nm excitation source for fluorescence imaging. Reflectance images, obtained simultaneously with near infrared light, permitted precise surface registration of individual frames of the fluorescence imaging. In-vivo imaging was then compared to ex-vivo confocal microscopy of the same tissue. Results Superficial focus (innermost retina at all depths within the NFL revealed a vasculature with extremely long capillaries, thin walls, little variation in caliber and parallel-linked structure oriented parallel to the NFL axons, typical of the radial peripapillary capillaries (RPCs. However, at a deeper focus beneath the NFL, (toward outer retina the polygonal pattern typical of the ganglion cell layer (inner and outer retinal vasculature was seen. These distinguishing patterns were also seen on histological examination of the same retinas. Furthermore, the thickness of the RPC beds and the caliber of individual RPCs determined by imaging closely matched that measured in histological sections. Conclusion This robust method demonstrates in-vivo, high-resolution, confocal imaging of the vasculature through the full thickness of the NFL in the living macaque, in precise agreement with histology. FAO provides a new tool to examine possible primary or secondary role of the nerve fiber layer vasculature in retinal

  8. Peripheral origins and functional characteristics of vibration-sensitive VIIIth nerve fibers in the frog Rana temporaria

    DEFF Research Database (Denmark)

    Jøgensen, Morten Buhl; Christensen-Dalsgaard, Jakob

    1991-01-01

    were studied. 2) Vibration-sensitive fibers were found in both the anterior and posterior branch of the VIIIth nerve. 3) No vibration-sensitive fibers were found in the lagenar nerve. 4) The vibration-sensitive fibers in the posterior branch probably innervated the amphibian papilla and many...... of these fibers also responded to low-frequency sound. 5) The vibration-sensitive fibers in the anterior branch probably innervated the sacculus and the utriculus. 6) Hence, the grassfrog has at least two, and probably three, vibration-sensitive organs in the inner ear. 7) All fibers had V-shaped vibrational...... tuning curves. In the posterior branch best frequencies (BFs) ranged from 10 to 300 Hz, in the anterior branch from 10 to 100 Hz. In the posterior branch spike-rate thresholds at BF ranged from 0.04 to 1.28 cm/s2, in the anterior branch from 0.02 to 1.28 cm/s2. All fibers showed strong synchronization...

  9. Optical coherence tomography evaluation of retinal nerve fiber layer in longitudinally extensive transverse myelitis

    Directory of Open Access Journals (Sweden)

    Frederico C. Moura

    2011-02-01

    Full Text Available OBJECTIVE: To compare optical coherence tomography (OCT measurements on the retinal nerve fiber layer (RNFL of healthy controls and patients with longitudinally extensive transverse myelitis (LETM without previous optic neuritis. METHOD: Twenty-six eyes from 26 patients with LETM and 26 control eyes were subjected to automated perimetry and OCT for comparison of RNFL measurements. RESULTS: The mean deviation values from perimetry were significantly lower in patients with LETM than in controls (p<0.0001. RNFL measurements in the nasal quadrant and in the 3-o'clock segment were significantly smaller in LETM eyes than in controls. (p=0.04 and p=0.006, respectively. No significantly differences in other RNFL measurements were found. CONCLUSION: Patients with LETM may present localized RNFL loss, particularly on the nasal side of the optic disc, associated with slight visual field defects, even in the absence of previous episodes of optic neuritis. These findings emphasize the fact that patients with LETM may experience attacks of subclinical optic nerve damage.

  10. Expression of growth-associated protein 43 in the skin nerve fibers of patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Bursova, Sarka; Dubovy, Petr; Vlckova-Moravcova, Eva; Nemec, Martin; Klusakova, Ilona; Belobradkova, Jana; Bednarik, Josef

    2012-04-15

    The growth-associated protein 43 (GAP-43) is known as a marker of regenerating nerve fibers and their continuous remodeling in the adult human skin. The purpose of this pilot study was to investigate a possible role for GAP-43 in the detection of the early stages of small-fiber neuropathy in patients with type 2 diabetes mellitus (DM2) as compared with a well- established and validated parameter - intra-epidermal nerve fiber density (IENFD) of protein gene product 9.5 (PGP 9.5) immunoreactive intra-epidermal C fibers. In a group of 21 patients with DM2 within three years of diagnosis (13 men, 8 women; mean age 53.9±12.8; range 30-74) and a group of 17 healthy volunteers (8 men, 9 women; mean age 55.8±8.5; range 45-70 years), skin punch biopsies were taken from a distal calf and double immunostained with both PGP 9.5 and GAP-43. In healthy controls, 96.8% of 629 PGP 9.5 immunoreactive fibers were immunostained with GAP-43; the proportion of PGP 9.5 intra-epidermal nerve fibers immunoreactive for GAP-43 in control subjects ranged from 86.5 to 100%. In DM2 patients, IENFD was significantly lower compared to controls (median, 1.5 vs. 11.2/mm; pDM2 patients compared to healthy controls (73.6% of 337 PGP 9.5 positive fibers; p<0.001); ranged from 0 to 98.1%. In conclusion, these results show that impaired regeneration of intra-epidermal C fibers in the early stages of type 2 diabetes mellitus, as indicated by GAP-43, might be a marker of incipient diabetic neuropathy. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Non-tip auditory-nerve responses that are suppressed by low-frequency bias tones originate from reticular lamina motion.

    Science.gov (United States)

    Nam, Hui; Guinan, John J

    2017-12-14

    Recent cochlear mechanical measurements show that active processes increase the motion response of the reticular lamina (RL) at frequencies more than an octave below the local characteristic frequency (CF) for CFs above 5 kHz. A possible correlate is that in high-CF (>5 kHz) auditory-nerve (AN) fibers, responses to frequencies 1-3 octaves below CF ("tail" frequencies) can be inhibited by medial olivocochlear (MOC) efferents. These results indicate that active processes enhance the sensitivity of tail-frequency RL and AN responses. Perhaps related is that some apical low-CF AN fibers have tuning-curve (TC) "side-lobe" response areas at frequencies above and below the TC-tip that are MOC inhibited. We hypothesized that the tail and side-lobe responses are enhanced by the same active mechanisms as CF cochlear amplification. If responses to CF, tail-frequency, and TC-side-lobe tones are all enhanced by prestin motility controlled by outer-hair-cell (OHC) transmembrane voltage, then they should depend on OHC stereocilia position in the same way. To test this, we cyclically changed the OHC-stereocilia mechano-electric-transduction (MET) operating point with low-frequency "bias" tones (BTs) and increased the BT level until the BT caused quasi-static OHC MET saturation that reduced or "suppressed" the gain of OHC active processes. While measuring cat AN-fiber responses, 50 Hz BT level series, 70-120 dB SPL, were run alone and with CF tones, or 2.5 kHz tail-frequency tones, or side-lobe tones. BT-tone-alone responses were used to exclude BT sound levels that produced AN responses that might obscure BT suppression. Data were analyzed to show the BT phase that suppressed the tone responses at the lowest sound level. We found that AN responses to CF, tail-frequency, and side-lobe tones were suppressed at the same BT phase in almost all cases. The data are consistent with the enhancement of responses to CF, tail-frequency, and side-lobe tones all being due to the same

  12. Human primordial germ cells migrate along nerve fibers and Schwann cells from the dorsal hind gut mesentery to the gonadal ridge

    DEFF Research Database (Denmark)

    Møllgård, Kjeld; Jespersen, Åse; Lutterodt, Melissa Catherine

    2010-01-01

    The aim of this study was to investigate the spatiotemporal development of autonomic nerve fibers and primordial germ cells (PGCs) along their migratory route from the dorsal mesentery to the gonadal ridges in human embryos using immunohistochemical markers and electron microscopy. Autonomic nerve...... arrive at the gonadal ridge between 29 and 33 days pc. In conclusion, our data suggest that PGCs in human embryos preferentially migrate along autonomic nerve fibers from the dorsal mesentery to the developing gonad where they are delivered via a fine nerve plexus....

  13. Nerve fiber layer (NFL) degeneration associated with acute q-switched laser exposure in the nonhuman primate

    Science.gov (United States)

    Zwick, Harry; Zuclich, Joseph A.; Stuck, Bruce E.; Gagliano, Donald A.; Lund, David J.; Glickman, Randolph D.

    1995-01-01

    We have evaluated acute laser retinal exposure in non-human primates using a Rodenstock scanning laser ophthalmoscope (SLO) equipped with spectral imaging laser sources at 488, 514, 633, and 780 nm. Confocal spectral imaging at each laser wavelength allowed evaluation of the image plane from deep within the retinal vascular layer to the more superficial nerve fiber layer in the presence and absence of the short wavelength absorption of the macular pigment. SLO angiography included both fluorescein and indocyanine green procedures to assess the extent of damage to the sensory retina, the retinal pigment epithelium (RPE), and the choroidal vasculature. All laser exposures in this experiment were from a Q-switched Neodymium laser source at an exposure level sufficient to produce vitreous hemorrhage. Confocal imaging of the nerve fiber layer revealed discrete optic nerve sector defects between the lesion site and the macula (retrograde degeneration) as well as between the lesion site and the optic disk (Wallerian degeneration). In multiple hemorrhagic exposures, lesions placed progressively distant from the macula or overlapping the macula formed bridging scars visible at deep retinal levels. Angiography revealed blood flow disturbance at the retina as well as at the choroidal vascular level. These data suggest that acute parafoveal laser retinal injury can involve both direct full thickness damage to the sensory and non-sensory retina and remote nerve fiber degeneration. Such injury has serious functional implications for both central and peripheral visual function.

  14. Retinal nerve fiber and optic disc morphology using spectral-domain optical coherence tomography in scleroderma patients.

    Science.gov (United States)

    Sahin-Atik, Sevinc; Koc, Feray; Akin-Sari, Sirin; Ozmen, Mustafa

    2017-05-11

    To evaluate the optic nerve head parameters and peripapillary retinal nerve fiber layer using spectral-domain optical coherence tomography (SD-OCT) in a systemic sclerosis (SSc) cohort and age-matched controls to determine whether SSc patients have an increased risk of normal-tension glaucoma (NTG). We examined 30 patients (3 male, 27 female) with SSc and 28 age- and sex-matched controls. Retinal nerve fiber and optic disc morphology were evaluated using Cirrus SD-OCT. Optic disc morphology measurements including disc area, rim area, average and vertical cup/disc (C/D) ratio, and cup volume were not significantly different between the study groups. The average and 4-quadrant retinal nerve fiber layer (RNFL) measurements of the C/D >0.3 subgroups were not significantly different in the patients and controls. These values were also similar for the C/D >0.5 subgroups except that the average inferior quadrant RNFL thickness of the right eyes in the patient subgroup was significantly thinner than in the control subgroup (p<0.05). Our SSc cohort had relatively shorter disease duration but increased prevalence of early glaucomatous damage signs. Our findings indicate that SSc is a risk factor for developing normal-tension glaucoma. Further studies combined with visual field evaluation are necessary to identify the long-term glaucomatous effects of SSc.

  15. DC-Evoked Modulation of Excitability of Myelinated Nerve Fibers and Their Terminal Branches; Differences in Sustained Effects of DC.

    Science.gov (United States)

    Kaczmarek, Dominik; Jankowska, Elzbieta

    2018-03-15

    Direct current (DC) evokes long-lasting changes in neuronal networks both presynaptically and postsynaptically and different mechanisms were proposed to be involved in them. Different mechanisms were also suggested to account for the different dynamics of presynaptic DC actions on myelinated nerve fibers stimulated before they entered the spinal gray matter and on their terminal branches. The aim of the present study was to examine whether these different dynamics might be related to differences in the involvement of K + channels. To this end, we compared effects of the K + channel blocker 4-amino-pyridine (4-AP) on DC-evoked changes in the excitability of afferent fibers stimulated within the dorsal columns (epidurally) and within their projection areas in the dorsal horn and motor nuclei (intraspinally). 4-AP was applied systemically in deeply anesthetized rats. DC-evoked increases in the excitability of epidurally stimulated afferent nerve fibers, and increases in field potentials evoked by these fibers, were not affected by 4-AP. In contrast, sustained decreases rather than increases in the excitability of intraspinally stimulated terminal nerve branches were evoked by local application of DC in conjunction with 4-AP. The study leads to the conclusion that 4-AP-sensitive K + channels contribute to the sustained DC-evoked post-polarization increases in the excitability at the level of terminal branches of nerve fibers but not of the nodes of Ranvier nor within the juxta-paranodal regions where other mechanisms would be involved in inducing the sustained DC-evoked changes. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Retinal nerve fiber layer thickness in normals measured by spectral domain OCT.

    Science.gov (United States)

    Bendschneider, Delia; Tornow, Ralf P; Horn, Folkert K; Laemmer, Robert; Roessler, Christopher W; Juenemann, Anselm G; Kruse, Friedrich E; Mardin, Christian Y

    2010-09-01

    To determine normal values for peripapillary retinal nerve fiber layer thickness (RNFL) measured by spectral domain Optical Coherence Tomography (SOCT) in healthy white adults and to examine the relationship of RNFL with age, gender, and clinical variables. The peripapillary RNFL of 170 healthy patients (96 males and 74 females, age 20 to 78 y) was imaged with a high-resolution SOCT (Spectralis HRA+OCT, Heidelberg Engineering) in an observational cross-sectional study. RNFL thickness was measured around the optic nerve head using 16 automatically averaged, consecutive circular B-scans with 3.4-mm diameter. The automatically segmented RNFL thickness was divided into 32 segments (11.25 degrees each). One randomly selected eye per subject entered the study. Mean RNFL thickness in the study population was 97.2 ± 9.7 μm. Mean RNFL thickness was significantly negatively correlated with age (r = -0.214, P = 0.005), mean RNFL decrease per decade was 1.90 μm. As age dependency was different in different segments, age-correction of RNFL values was made for all segments separately. Age-adjusted RNFL thickness showed a significant correlation with axial length (r = -0.391, P = 0.001) and with refractive error (r = 0.396, P<0.001), but not with disc size (r = 0.124). Normal RNFL results with SOCT are comparable to those reported with time-domain OCT. In accordance with the literature on other devices, RNFL thickness measured with SOCT was significantly correlated with age and axial length. For creating a normative database of SOCT RNFL values have to be age adjusted.

  17. Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics.

    Science.gov (United States)

    Kocaoglu, Omer P; Cense, Barry; Jonnal, Ravi S; Wang, Qiang; Lee, Sangyeol; Gao, Weihua; Miller, Donald T

    2011-08-15

    Early detection of axonal tissue loss in retinal nerve fiber layer (RNFL) is critical for effective treatment and management of diseases such as glaucoma. This study aims to evaluate the capability of ultrahigh-resolution optical coherence tomography with adaptive optics (UHR-AO-OCT) for imaging the RNFL axonal bundles (RNFBs) with 3×3×3μm(3) resolution in the eye. We used a research-grade UHR-AO-OCT system to acquire 3°×3° volumes in four normal subjects and one subject with an arcuate retinal nerve fiber layer defect (n=5; 29-62years). Cross section (B-scans) and en face (C-scan) slices extracted from the volumes were used to assess visibility and size distribution of individual RNFBs. In one subject, we reimaged the same RNFBs twice over a 7month interval and compared bundle width and thickness between the two imaging sessions. Lastly we compared images of an arcuate RNFL defect acquired with UHR-AO-OCT and commercial OCT (Heidelberg Spectralis). Individual RNFBs were distinguishable in all subjects at 3° retinal eccentricity in both cross-sectional and en face views (width: 30-50μm, thickness: 10-15μm). At 6° retinal eccentricity, RNFBs were distinguishable in three of the five subjects in both views (width: 30-45μm, thickness: 20-40μm). Width and thickness RNFB measurements taken 7months apart were strongly correlated (p<0.0005). Mean difference and standard deviation of the differences between the two measurement sessions were -0.1±4.0μm (width) and 0.3±1.5μm (thickness). UHR-AO-OCT outperformed commercial OCT in terms of clarity of the microscopic retina. To our knowledge, these are the first measurements of RNFB cross section reported in the living human eye. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Persistent alterations in active and passive electrical membrane properties of regenerated nerve fibers of man and mice

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Alvarez Herrero, Susana; Rosberg, Mette R.

    2016-01-01

    Excitability of regenerated fibers remains impaired due to changes in both passive cable properties and alterations in the voltage-dependent membrane function. These abnormalities were studied by mathematical modeling in human regenerated nerves and experimental studies in mice. In three adult male...... activity protocol triggered partial Wallerian degeneration in regenerated nerves but not in control nerves from age-matched mice. The current data suggest that the nodal voltage-gated ion channel machinery is restored in regenerated axons, although the electrical separation from the internodal compartment...... remains compromised. Due to the persistent increase in number of nodes, the increased activity-dependent Na+ influx could lead to hyperactivity of the Na+/K+ pump resulting in membrane hyperpolarization and neurotoxic energy insufficiency during strenuous activity....

  19. Diffusion tensor imaging with quantitative evaluation and fiber tractography of lumbar nerve roots in sciatica

    International Nuclear Information System (INIS)

    Shi, Yin; Zong, Min; Xu, Xiaoquan; Zou, Yuefen; Feng, Yang; Liu, Wei; Wang, Chuanbing; Wang, Dehang

    2015-01-01

    Highlights: •In the present study, we first elected ROIs corresponding to the proximal, medial, and distal levels of the lumbar foraminal zone. •The ROC analysis for FA values of distal nerves indicated a high level of reliability in the diagnosis of sciatica. •The declining trend of FA values from proximal to distal along the nerve tract may correlate with the disparity of axonal regeneration at different levels. •DTI is able to quantitatively evaluate compressed nerve roots and has a higher sensitivity and specificity for diagnosing sciatica than conventional MR imaging. •DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and probable localization of nerve compression. -- Abstract: Objective: To quantitatively evaluate nerve roots by measuring fractional anisotropy (FA) values in healthy volunteers and sciatica patients, visualize nerve roots by tractography, and compare the diagnostic efficacy between conventional magnetic resonance imaging (MRI) and DTI. Materials and methods: Seventy-five sciatica patients and thirty-six healthy volunteers underwent MR imaging using DTI. FA values for L5–S1 lumbar nerve roots were calculated at three levels from DTI images. Tractography was performed on L3–S1 nerve roots. ROC analysis was performed for FA values. Results: The lumbar nerve roots were visualized and FA values were calculated in all subjects. FA values decreased in compressed nerve roots and declined from proximal to distal along the compressed nerve tracts. Mean FA values were more sensitive and specific than MR imaging for differentiating compressed nerve roots, especially in the far lateral zone at distal nerves. Conclusions: DTI can quantitatively evaluate compressed nerve roots, and DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and localization of probable nerve compression. DTI has great potential utility for evaluating lumbar nerve compression in sciatica

  20. Diffusion tensor imaging with quantitative evaluation and fiber tractography of lumbar nerve roots in sciatica

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yin; Zong, Min; Xu, Xiaoquan; Zou, Yuefen; Feng, Yang; Liu, Wei; Wang, Chuanbing; Wang, Dehang, E-mail: njmu_wangdehang@126.com

    2015-04-15

    Highlights: •In the present study, we first elected ROIs corresponding to the proximal, medial, and distal levels of the lumbar foraminal zone. •The ROC analysis for FA values of distal nerves indicated a high level of reliability in the diagnosis of sciatica. •The declining trend of FA values from proximal to distal along the nerve tract may correlate with the disparity of axonal regeneration at different levels. •DTI is able to quantitatively evaluate compressed nerve roots and has a higher sensitivity and specificity for diagnosing sciatica than conventional MR imaging. •DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and probable localization of nerve compression. -- Abstract: Objective: To quantitatively evaluate nerve roots by measuring fractional anisotropy (FA) values in healthy volunteers and sciatica patients, visualize nerve roots by tractography, and compare the diagnostic efficacy between conventional magnetic resonance imaging (MRI) and DTI. Materials and methods: Seventy-five sciatica patients and thirty-six healthy volunteers underwent MR imaging using DTI. FA values for L5–S1 lumbar nerve roots were calculated at three levels from DTI images. Tractography was performed on L3–S1 nerve roots. ROC analysis was performed for FA values. Results: The lumbar nerve roots were visualized and FA values were calculated in all subjects. FA values decreased in compressed nerve roots and declined from proximal to distal along the compressed nerve tracts. Mean FA values were more sensitive and specific than MR imaging for differentiating compressed nerve roots, especially in the far lateral zone at distal nerves. Conclusions: DTI can quantitatively evaluate compressed nerve roots, and DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and localization of probable nerve compression. DTI has great potential utility for evaluating lumbar nerve compression in sciatica.

  1. Variations in retinal nerve fiber layer measurements on optical coherence tomography after implantation of trifocal intraocular lens.

    Science.gov (United States)

    García-Bella, Javier; Martínez de la Casa, José M; Talavero González, Paula; Fernández-Vigo, José I; Valcarce Rial, Laura; García-Feijóo, Julián

    2018-01-01

    To establish the changes produced after implantation of a trifocal intraocular lens (IOL) on retinal nerve fiber layer measurements performed with Fourier-domain optical coherence tomography (OCT). This prospective study included 100 eyes of 50 patients with bilateral cataract in surgical range, no other associated ocular involvement, refractive errors between +5 and -5 spherical diopters, and less than 1.5 D of corneal astigmatism. The eyes were operated by phacoemulsification with implantation of 2 different trifocal IOLs (FineVision and AT LISA tri 839MP) in randomized equal groups. Cirrus OCT and Spectralis OCT were performed before surgery and 3 months later. Both analyzed the thickness of the nerve fiber layer and thickness divided by quadrants (6 in case of Spectralis and 4 in case of Cirrus HD). The mean age of patients was 67.5 ± 5.8 years. The global nerve fiber layer thickness measured with Spectralis OCT was 96.77 μm before surgery and 99.55 μm after. With Cirrus OCT, the global thickness was 85.29 μm before surgery and 89.77 μm after. Statistically significant differences in global thickness measurements between preimplantation and postimplantation of the IOL were found with both OCT in the 2 groups. Statistically significant differences were also found in temporal and superior quadrants. The implantation of a diffractive trifocal IOL alters the results of the optic nerve fiber layer on Fourier-domain OCT in these patients, which should be taken into account in the posterior study of these patients.

  2. Paradoxical thinning of the retinal nerve fiber layer after reversal of cupping: A case report of primary infantile glaucoma

    Directory of Open Access Journals (Sweden)

    Ta Chen Chang

    2016-01-01

    Full Text Available The circumpapillary retinal nerve fiber layer (RNFL thickness was assessed by spectral domain optical coherent tomography (SD-OCT before and after surgical reduction of intraocular pressure in an eye with primary infantile glaucoma. In this case, a postoperative reduction of cupping and a subsequent increase in neuroretinal rim area is associated with a paradoxical thinning of the RNFL. This is the first-known characterization of cupping reversal using SD-OCT.

  3. Changes in retinal nerve fiber layer thickness after spinal surgery in the prone position: a prospective study

    Directory of Open Access Journals (Sweden)

    Baran Gencer

    2015-02-01

    Full Text Available BACKGROUND AND OBJECTIVES: Changes in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. METHODS: This prospective study included 30 patients undergoing spinal surgery. Retinal nerve fiber layer thickness were measured one day before and after the surgery by using optical coherence tomography. Intraocular pressure was measured by tonopen six times at different position and time-duration: supine position (baseline; 10 min after intubation (Supine 1; 10 (Prone 1, 60 (Prone 2, 120 (Prone 3 min after prone position; and just after postoperative supine position (Supine 2. RESULTS: Our study involved 10 male and 20 female patients with the median age of 57 years. When postoperative retinal nerve fiber layer thickness measurements were compared with preoperative values, a statistically significant thinning was observed in inferior and nasal quadrants (p = 0.009 and p = 0.003, respectively. We observed a statistically significant intraocular pressure decrease in Supine 1 and an increase in both Prone 2 and Prone 3 when compared to the baseline. Mean arterial pressure and ocular perfusion pressure were found to be significantly lower in Prone 1, Prone 2 and Prone 3, when compared with the baseline. CONCLUSIONS: Our study has shown increase in intraocular pressure during spinal surgery in prone position. A statistically significant retinal nerve fiber layer thickness thinning was seen in inferior and nasal quadrants one day after the spinal surgery.

  4. Localization of substance P, calcitonin gene related peptide and galanin in the nerve fibers of porcine cystic ovaries

    Directory of Open Access Journals (Sweden)

    Mariusz Majewski

    2012-01-01

    Full Text Available In a previous study, we showed that both the noradrenergic and cholinergic component of ovarian innervation is markedly changed in porcine cystic ovaries. The present study is aimed at elucidating the distribution pattern of substance P- (SP, calcitonin gene related peptide CGRP- and/or galanin (GAL-containing nerve fibers within porcine cystic ovaries. The status polycysticus was induced by dexamethasone phosphate disodium salt i.m. injections performed from the 7th until the 21st day of the first studied estrous cycle. During the same period of time, gilts of the control group received saline. All animals were slaughtered on the expected 11th day of the second studied estrous cycle, and their ovaries were collected. When compared to control gonad, a distinct difference in the distribution pattern and the density of SP-, CGRP- and/or GAL-immunoreactive (GAL-IR nerve fibers was observed. Thus, unlike in the control gonad, SP- and/or CGRP-IR perivascular nerve fibers were found to supply medullar blood vessels of polycystic ovary. Furthermore, the number of GAL-IR nerve fibers contributing to the ground plexus in polycystic ovaries was higher than that observed in the control gonads. Thus, as may be judged from the profound changes in the distribution pattern of differently chemically coded afferent terminals within polycystic gonads, it appears possible that neuropeptides released from these terminals may take part in the etiopathogenesis of this disorder. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 622–630

  5. Specific paucity of unmyelinated C-fibers in cutaneous peripheral nerves of the African naked-mole rat: comparative analysis using six species of Bathyergidae.

    Science.gov (United States)

    St John Smith, Ewan; Purfürst, Bettina; Grigoryan, Tamara; Park, Thomas J; Bennett, Nigel C; Lewin, Gary R

    2012-08-15

    In mammalian peripheral nerves, unmyelinated C-fibers usually outnumber myelinated A-fibers. By using transmission electron microscopy, we recently showed that the saphenous nerve of the naked mole-rat (Heterocephalus glaber) has a C-fiber deficit manifested as a substantially lower C:A-fiber ratio compared with other mammals. Here we determined the uniqueness of this C-fiber deficit by performing a quantitative anatomical analysis of several peripheral nerves in five further members of the Bathyergidae mole-rat family: silvery (Heliophobius argenteocinereus), giant (Fukomys mechowii), Damaraland (Fukomys damarensis), Mashona (Fukomys darlingi), and Natal (Cryptomys hottentotus natalensis) mole-rats. In the largely cutaneous saphenous and sural nerves, the naked mole-rat had the lowest C:A-fiber ratio (∼1.5:1 compared with ∼3:1), whereas, in nerves innervating both skin and muscle (common peroneal and tibial) or just muscle (lateral/medial gastrocnemius), this pattern was mostly absent. We asked whether lack of hair follicles alone accounts for the C-fiber paucity by using as a model a mouse that loses virtually all its hair as a consequence of conditional deletion of the β-catenin gene in the skin. These β-catenin loss-of function mice (β-cat LOF mice) displayed only a mild decrease in C:A-fiber ratio compared with wild-type mice (4.42 compared with 3.81). We suggest that the selective cutaneous C-fiber deficit in the cutaneous nerves of naked mole-rats is unlikely to be due primarily to lack of skin hair follicles. Possible mechanisms contributing to this unique peripheral nerve anatomy are discussed. Copyright © 2012 Wiley Periodicals, Inc.

  6. Diffusion tensor imaging with quantitative evaluation and fiber tractography of lumbar nerve roots in sciatica.

    Science.gov (United States)

    Shi, Yin; Zong, Min; Xu, Xiaoquan; Zou, Yuefen; Feng, Yang; Liu, Wei; Wang, Chuanbing; Wang, Dehang

    2015-04-01

    To quantitatively evaluate nerve roots by measuring fractional anisotropy (FA) values in healthy volunteers and sciatica patients, visualize nerve roots by tractography, and compare the diagnostic efficacy between conventional magnetic resonance imaging (MRI) and DTI. Seventy-five sciatica patients and thirty-six healthy volunteers underwent MR imaging using DTI. FA values for L5-S1 lumbar nerve roots were calculated at three levels from DTI images. Tractography was performed on L3-S1 nerve roots. ROC analysis was performed for FA values. The lumbar nerve roots were visualized and FA values were calculated in all subjects. FA values decreased in compressed nerve roots and declined from proximal to distal along the compressed nerve tracts. Mean FA values were more sensitive and specific than MR imaging for differentiating compressed nerve roots, especially in the far lateral zone at distal nerves. DTI can quantitatively evaluate compressed nerve roots, and DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and localization of probable nerve compression. DTI has great potential utility for evaluating lumbar nerve compression in sciatica. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Optic Nerve Disorders

    Science.gov (United States)

    The optic nerve is a bundle of more than 1 million nerve fibers that carry visual messages. You have one connecting ... retina) to your brain. Damage to an optic nerve can cause vision loss. The type of vision ...

  8. Automated retinal nerve fiber layer defect detection using fundus imaging in glaucoma.

    Science.gov (United States)

    Panda, Rashmi; Puhan, N B; Rao, Aparna; Padhy, Debananda; Panda, Ganapati

    2018-06-01

    Retinal nerve fiber layer defect (RNFLD) provides an early objective evidence of structural changes in glaucoma. RNFLD detection is currently carried out using imaging modalities like OCT and GDx which are expensive for routine practice. In this regard, we propose a novel automatic method for RNFLD detection and angular width quantification using cost effective redfree fundus images to be practically useful for computer-assisted glaucoma risk assessment. After blood vessel inpainting and CLAHE based contrast enhancement, the initial boundary pixels are identified by local minima analysis of the 1-D intensity profiles on concentric circles. The true boundary pixels are classified using random forest trained by newly proposed cumulative zero count local binary pattern (CZC-LBP) and directional differential energy (DDE) along with Shannon, Tsallis entropy and intensity features. Finally, the RNFLD angular width is obtained by random sample consensus (RANSAC) line fitting on the detected set of boundary pixels. The proposed method is found to achieve high RNFLD detection performance on a newly created dataset with sensitivity (SN) of 0.7821 at 0.2727 false positives per image (FPI) and the area under curve (AUC) value is obtained as 0.8733. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Macular and peripapillary retinal nerve fiber layer thickness in children with hyperopic anisometropic amblyopia

    Directory of Open Access Journals (Sweden)

    Shuang-Qing Wu

    2013-02-01

    Full Text Available AIM:To compare the retinal nerve fiber layer (RNFL thickness and macular thickness in the amblyopic eye with that in the sound eye of children with hyperopic anisometropic amblyopia using optical coherence tomography (OCT.METHODS: A prospective, nonrandom, intraindividual comparative cohort study includes 72 children with hyperopic anisometropic amblyopia in a single center. Macular thickness, macular foveola thickness, and peripapillary RNFL thickness were compared between the amblyopia eyes and the contralateral sound eyes.RESULTS:There were 38 male and 34 female patients, with a mean age as 9.7±1.9 years (range, 5–16 years. Hyperopic was +3.62±1.16D (range +2.00D to +6.50D in the amblyopic eyes, which was significantly higher in the control eyes with +0.76±0.90D (range 0D to +2.00D (P P = 0.02. The mean macular foveola thickness was significantly thicker in the amblyopic eyes than the contralateral sound eyes (181.4±14.2µm vs 175.2±13.3µm, P CONCLUSION:Eyes with hyperopic anisometropic amblyopia are found thicker macular foveola and peripapillary RNFL than the contralateral eyes in children.

  10. Perimetric and retinal nerve fiber layer findings in patients with Parkinson’s disease

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    Tsironi Evangelia E

    2012-10-01

    Full Text Available Abstract Background Visual dysfunction is common in Parkinson’s disease (PD. It remains, however, unknown whether it is related to structural alterations of the retina. The aim of this study is to compare visual field (VF findings and circumpapillary retinal nerve fiber layer (RNFL thickness in a series of PD patients and normal controls, in order to assess possible retinal anatomical changes and/or functional damage associated with PD. Methods PD patients and controls were recruited and underwent VF testing with static automated perimetry and RNFL examination with optical coherence tomography (OCT. Cognitive performance using Mini Mental State Examination (MMSE, PD staging using modified Hoehn and Yahr (H-Y scale and duration of the disease was recorded in PD patients. Results One randomly selected eye from each of 24 patients and 24 age-matched controls was included. OCT RNFL thickness analysis revealed no difference in the inferior, superior, nasal or temporal sectors between the groups. The average peripapillary RNFL was also similar in the two groups. However, perimetric indices of generalized sensitivity loss (mean deviation and localized scotomas (pattern standard deviation were worse in patients with PD compared to controls (p  Conclusion PD patients may demonstrate glaucomatous-like perimetric defects even in the absence of decreased RNFL thickness.

  11. Hyperbaric Oxygen Therapy Can Induce Angiogenesis and Regeneration of Nerve Fibers in Traumatic Brain Injury Patients

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    Sigal Tal

    2017-10-01

    Full Text Available Background: Recent clinical studies in stroke and traumatic brain injury (TBI victims suffering chronic neurological injury present evidence that hyperbaric oxygen therapy (HBOT can induce neuroplasticity.Objective: To assess the neurotherapeutic effect of HBOT on prolonged post-concussion syndrome (PPCS due to TBI, using brain microstructure imaging.Methods: Fifteen patients afflicted with PPCS were treated with 60 daily HBOT sessions. Imaging evaluation was performed using Dynamic Susceptibility Contrast-Enhanced (DSC and Diffusion Tensor Imaging (DTI MR sequences. Cognitive evaluation was performed by an objective computerized battery (NeuroTrax.Results: HBOT was initiated 6 months to 27 years (10.3 ± 3.2 years from injury. After HBOT, DTI analysis showed significantly increased fractional anisotropy values and decreased mean diffusivity in both white and gray matter structures. In addition, the cerebral blood flow and volume were increased significantly. Clinically, HBOT induced significant improvement in the memory, executive functions, information processing speed and global cognitive scores.Conclusions: The mechanisms by which HBOT induces brain neuroplasticity can be demonstrated by highly sensitive MRI techniques of DSC and DTI. HBOT can induce cerebral angiogenesis and improve both white and gray microstructures indicating regeneration of nerve fibers. The micro structural changes correlate with the neurocognitive improvements.

  12. Agreement of Two Different Spectral Domain Optical Coherence Tomography Instruments for Retinal Nerve Fiber Layer Measurements

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    Hooshang Faghihi

    2014-01-01

    Full Text Available Purpose: To determine the agreement between Spectralis and Cirrus spectral domain optical coherence tomography (SD-OCT measurements of peripapillary retinal nerve fiber layer (RNFL thickness. Methods: Suspected or confirmed cases of glaucoma who met the inclusion criteria underwent peripapillary RNFL thickness measurement using both the Spectralis and Cirrus on the same day within a few minutes. Results: Measurements were performed on 103 eyes of 103 patients with mean age of 50.4±17.7 years. Mean RNFL thickness was 89.22±15.87 versus 84.54±13.68 μm using Spectralis and Cirrus, respectively. The difference between measurements and the average of paired measurements with the two devices showed a significant linear relationship. Bland-Altman plots demonstrated that Spectralis thickness values were systematically larger than that of Cirrus. Conclusion: Spectralis OCT generates higher peripapillary RNFL thickness readings as compared to Cirrus OCT; this should be kept in mind when values obtained with different instruments are compared during follow-up.

  13. Cone dysfunctions in retinitis pigmentosa with retinal nerve fiber layer thickening.

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    Sobacı, Güngör; Ozge, Gökhan; Gündoğan, Fatih Ç

    2012-01-01

    To investigate whether or not thicker retinal nerve fiber layer (RNFL) in retinitis pigmentosa (RP) patients relates to functional abnormalities of the photoreceptors. Optical coherence tomography-based RNFL thickness was measured by Stratus-3™ (Zeiss, Basel, Switzerland) optical coherence tomography and electroretinogram (ERG) recordings made using the RETI-port(®) system (Roland, Wiesbaden, Germany) in 27 patients with retinitis pigmentosa and in 30 healthy subjects. Photopic ERG b-wave amplitude, cone ERG b-wave latency, 30 Hz flicker amplitude, and 30 Hz flicker latency had significant correlations to the RNFL-temporal (r = -0.55, P = 0.004, r = 0.68, P = 0.001, r = -0.65, P = 0.001, and r = -0.52, P = 0.007, respectively). Eyes with thicker RNFL (ten eyes) differed significantly from those with thinner RNFL (eight eyes) regarding cone ERG b-wave latency values only (P = 0.001). Thicker RNFL in patients with retinitis pigmentosa may be associated with functional abnormality of the cone system.

  14. Retina nerve fiber layer and choroidal thickness changes in obstructive sleep apnea syndrome.

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    Ozge, Gokhan; Dogan, Deniz; Koylu, Mehmet Talay; Ayyildiz, Onder; Akincioglu, Dorukcan; Mumcuoglu, Tarkan; Mutlu, Fatih Mehmet

    2016-01-01

    The purpose of this study was to determine the effects of obstructive sleep apnea syndrome (OSAS) on the submacular and peripapillary retinal nerve fiber layer (RNFL) and choroidal thickness (ChT). Eighty-four eyes of 42 male patients with OSAS and 112 eyes of 56 aged-matched and body mass index-matched healthy male subjects were enrolled in this case-control study. The ChT and peripapillary RNFL thickness was measured using enhanced depth imaging optical coherence tomography. The ChT and RNFL thickness measurements of the groups were compared, and correlations among the Apnea Hypopnea Index (AHI) values and these measurements were calculated. Right and left eyes were separately evaluated. There were no significant differences in the subfoveal and temporal ChT between the groups (p > 0.05). The OSAS group had significantly thicker ChT at 0.5 and 1.5 mm nasal to the fovea in both eyes than the control group (p 0.05). Between AHI and mean RNFL thickness showed a median negative correlation (r = - 0.411, p = 0.001). The choroidal thickening in patients with OSAS may be associated with the pathophysiology of the neurodegeneration process of the disease.

  15. Retinal nerve fiber layer and ganglion cell complex thickness in patients with type 2 diabetes mellitus

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    Mehmet Demir

    2014-01-01

    Full Text Available Aim: The aim of the following study is to evaluate the retinal nerve fiber layer (RNFL and ganglion cell complex (GCC thickness in patients with type 2 diabetes mellitus (DM. Materials and Methods: Average, inferior, and superior values of RNFL and GCC thickness were measured in 123 patients using spectral domain optical coherence tomography. The values of participants with DM were compared to controls. Diabetic patients were collected in Groups 1, 2 and 3. Group 1 = 33 participants who had no diabetic retinopathy (DR; Group 2 = 30 participants who had mild nonproliferative DR and Group 3 = 30 participants who had moderate non-proliferative DR. The 30 healthy participants collected in Group 4. Analysis of variance test and a multiple linear regression analysis were used for statistical analysis. Results: The values of RNFL and GCC in the type 2 diabetes were thinner than controls, but this difference was not statistically significant. Conclusions: This study showed that there is a nonsignificant loss of RNFL and GCC in patients with type 2 diabetes.

  16. Molecular architecture of myelinated nerve fibers: leaky paranodal junctions and paranodal dysmyelination.

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    Rosenbluth, Jack; Mierzwa, Amanda; Shroff, Seema

    2013-12-01

    Myelinated nerve fibers have evolved to optimize signal propagation. Each myelin segment is attached to the axon by the unique paranodal axoglial junction (PNJ), a highly complex structure that serves to define axonal ion channel domains and to direct nodal action currents through adjacent nodes. Surprisingly, this junction does not entirely seal the paranodal myelin sheath to the axon and thus does not entirely isolate the perinodal space from the internodal periaxonal space. Rather the paranode is penetrated by extracellular pathways between the myelin sheath and the axolemma for movement of molecules and the flow of current to and from the internodal axon. This review summarizes past and current studies demonstrating these pathways and considers what functional roles they subserve. In addition, modern genetic engineering methods permit modification of individual PNJ constituents, which provides an opportunity to define their specific functions. One component in particular, the transverse bands, plays a key role in maintaining the structure and function of the PNJ. Loss of transverse bands results not in frank demyelination but rather in subtle dysmyelination, which causes significant functional impairment. The consequences of such subtle defects in the PNJ are considered along with the relevance of these studies to human diseases of myelin.

  17. Detection of retinal nerve fiber layer defects in retinal fundus images using Gabor filtering

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    Hayashi, Yoshinori; Nakagawa, Toshiaki; Hatanaka, Yuji; Aoyama, Akira; Kakogawa, Masakatsu; Hara, Takeshi; Fujita, Hiroshi; Yamamoto, Tetsuya

    2007-03-01

    Retinal nerve fiber layer defect (NFLD) is one of the most important findings for the diagnosis of glaucoma reported by ophthalmologists. However, such changes could be overlooked, especially in mass screenings, because ophthalmologists have limited time to search for a number of different changes for the diagnosis of various diseases such as diabetes, hypertension and glaucoma. Therefore, the use of a computer-aided detection (CAD) system can improve the results of diagnosis. In this work, a technique for the detection of NFLDs in retinal fundus images is proposed. In the preprocessing step, blood vessels are "erased" from the original retinal fundus image by using morphological filtering. The preprocessed image is then transformed into a rectangular array. NFLD regions are observed as vertical dark bands in the transformed image. Gabor filtering is then applied to enhance the vertical dark bands. False positives (FPs) are reduced by a rule-based method which uses the information of the location and the width of each candidate region. The detected regions are back-transformed into the original configuration. In this preliminary study, 71% of NFLD regions are detected with average number of FPs of 3.2 per image. In conclusion, we have developed a technique for the detection of NFLDs in retinal fundus images. Promising results have been obtained in this initial study.

  18. Thickness related textural properties of retinal nerve fiber layer in color fundus images.

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    Odstrcilik, Jan; Kolar, Radim; Tornow, Ralf-Peter; Jan, Jiri; Budai, Attila; Mayer, Markus; Vodakova, Martina; Laemmer, Robert; Lamos, Martin; Kuna, Zdenek; Gazarek, Jiri; Kubena, Tomas; Cernosek, Pavel; Ronzhina, Marina

    2014-09-01

    Images of ocular fundus are routinely utilized in ophthalmology. Since an examination using fundus camera is relatively fast and cheap procedure, it can be used as a proper diagnostic tool for screening of retinal diseases such as the glaucoma. One of the glaucoma symptoms is progressive atrophy of the retinal nerve fiber layer (RNFL) resulting in variations of the RNFL thickness. Here, we introduce a novel approach to capture these variations using computer-aided analysis of the RNFL textural appearance in standard and easily available color fundus images. The proposed method uses the features based on Gaussian Markov random fields and local binary patterns, together with various regression models for prediction of the RNFL thickness. The approach allows description of the changes in RNFL texture, directly reflecting variations in the RNFL thickness. Evaluation of the method is carried out on 16 normal ("healthy") and 8 glaucomatous eyes. We achieved significant correlation (normals: ρ=0.72±0.14; p≪0.05, glaucomatous: ρ=0.58±0.10; p≪0.05) between values of the model predicted output and the RNFL thickness measured by optical coherence tomography, which is currently regarded as a standard glaucoma assessment device. The evaluation thus revealed good applicability of the proposed approach to measure possible RNFL thinning. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. The vestibulocochlear nerve (VIII).

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    Benoudiba, F; Toulgoat, F; Sarrazin, J-L

    2013-10-01

    The vestibulocochlear nerve (8th cranial nerve) is a sensory nerve. It is made up of two nerves, the cochlear, which transmits sound and the vestibular which controls balance. It is an intracranial nerve which runs from the sensory receptors in the internal ear to the brain stem nuclei and finally to the auditory areas: the post-central gyrus and superior temporal auditory cortex. The most common lesions responsible for damage to VIII are vestibular Schwannomas. This report reviews the anatomy and various investigations of the nerve. Copyright © 2013. Published by Elsevier Masson SAS.

  20. Conductive Hearing Loss Has Long-Lasting Structural and Molecular Effects on Presynaptic and Postsynaptic Structures of Auditory Nerve Synapses in the Cochlear Nucleus.

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    Clarkson, Cheryl; Antunes, Flora M; Rubio, Maria E

    2016-09-28

    Sound deprivation by conductive hearing loss increases hearing thresholds, but little is known about the response of the auditory brainstem during and after conductive hearing loss. Here, we show in young adult rats that 10 d of monaural conductive hearing loss (i.e., earplugging) leads to hearing deficits that persist after sound levels are restored. Hearing thresholds in response to clicks and frequencies higher than 8 kHz remain increased after a 10 d recovery period. Neural output from the cochlear nucleus measured at 10 dB above threshold is reduced and followed by an overcompensation at the level of the lateral lemniscus. We assessed whether structural and molecular substrates at auditory nerve (endbulb of Held) synapses in the cochlear nucleus could explain these long-lasting changes in hearing processing. During earplugging, vGluT1 expression in the presynaptic terminal decreased and synaptic vesicles were smaller. Together, there was an increase in postsynaptic density (PSD) thickness and an upregulation of GluA3 AMPA receptor subunits on bushy cells. After earplug removal and a 10 d recovery period, the density of synaptic vesicles increased, vesicles were also larger, and the PSD of endbulb synapses was larger and thicker. The upregulation of the GluA3 AMPAR subunit observed during earplugging was maintained after the recovery period. This suggests that GluA3 plays a role in plasticity in the cochlear nucleus. Our study demonstrates that sound deprivation has long-lasting alterations on structural and molecular presynaptic and postsynaptic components at the level of the first auditory nerve synapse in the auditory brainstem. Despite being the second most prevalent form of hearing loss, conductive hearing loss and its effects on central synapses have received relatively little attention. Here, we show that 10 d of monaural conductive hearing loss leads to an increase in hearing thresholds, to an increased central gain upstream of the cochlear nucleus at

  1. Retinal ganglion cell-inner plexiform and nerve fiber layers in neuromyelitis optica.

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    Hu, Sai-Jing; Lu, Pei-Rong

    2018-01-01

    To determine the thickness of the retinal ganglion cell-inner plexiform layer (GCIPL) and the retinal nerve fiber layer (RNFL) in patients with neuromyelitis optica (NMO). We conducted a cross-sectional study that included 30 NMO patients with a total of 60 eyes. Based on the presence or absence of optic neuritis (ON), subjects were divided into either the NMO-ON group (30 eyes) or the NMO-ON contra group (10 eyes). A detailed ophthalmologic examination was performed for each group; subsequently, the GCIPL and the RNFL were measured using high-definition optical coherence tomography (OCT). In the NMO-ON group, the mean GCIPL thickness was 69.28±21.12 µm, the minimum GCIPL thickness was 66.02±10.02 µm, and the RNFL thickness were 109.33±11.23, 110.47±3.10, 64.92±12.71 and 71.21±50.22 µm in the superior, inferior, temporal and nasal quadrants, respectively. In the NMO-ON contra group, the mean GCIPL thickness was 85.12±17.09 µm, the minimum GCIPL thickness was 25.39±25.1 µm, and the RNFL thicknesses were 148.33±23.22, 126.36±23.45, 82.21±22.30 and 83.36±31.28 µm in the superior, inferior, temporal and nasal quadrants, respectively. In the control group, the mean GCIPL thickness was 86.98±22.37 µm, the minimum GCIPL thickness was 85.28±10.75 µm, and the RNFL thicknesses were 150.22±22.73, 154.79±60.23, 82.33±7.01 and 85.62±13.81 µm in the superior, inferior, temporal and nasal quadrants, respectively. The GCIPL and RNFL were thinner in the NMO-ON contra group than in the control group ( P deviation (MD) and corrected pattern standard deviation (PSD) in the NMO-ON group ( P <0.05). The thickness of the GCIPL and RNFL, as measured using OCT, may indicate optic nerve damage in patients with NMO.

  2. Evaluation of retinal nerve fiber layer thickness and choroidal thickness in pseudoexfoliative glaucoma and pseudoexfoliative syndrome.

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    Ozge, Gokhan; Koylu, Mehmet Talay; Mumcuoglu, Tarkan; Gundogan, Fatih Cakir; Ozgonul, Cem; Ayyildiz, Onder; Kucukevcilioglu, Murat

    2016-05-01

    To compare retinal nerve fiber layer thickness (RNFLT) and choroidal thickness (ChT) measurements in eyes with pseudoexfoliative (PEX) glaucoma, PEX syndrome and healthy control eyes. Eighteen patients with PEX glaucoma in one eye and PEX syndrome in the fellow eye were included. The right eyes of thirty-nine age- and sex-matched healthy subjects were included as control group. All participants underwent a detailed biomicroscopic and funduscopic examination. RNFLT and ChT measurements were performed with a commercially available spectral-domain optical coherence tomography (SD-OCT). ChT measurements were performed by using enhanced depth imaging (EDI) mode. Patients with PEX underwent diurnal IOP measurements with 4-hour intervals before inclusion in the study. RNFLT results included the average measurement and 6 quadrants (temporal, inferotemporal, inferonasal, nasal, superonasal and supero-temporal). ChT measurements were performed in the subfoveal region and around the fovea (500µm and 1500 µm nasal and temporal to the fovea), as well as around the optic disc (average peripapillary and eight quadrants in the peripapillary region (temporal, inferotemporal, inferior, inferonasal, nasal, superonasal, superior, supero-temporal)). RNFLT in all quadrants and average thickness were significantly lower in PEX glaucoma eyes compared to PEX syndrome eyes and healthy control eyes (p0.05) except the inferotemporal quadrant. ChT measurements were similar between groups (p>0.05). Thinning of the RNFL in association with unchanged ChT may mean that the presence of PEX material is a much more significant risk factor than choroidal changes in the progression of PEX syndrome to PEX glaucoma.

  3. Additive diagnostic role of imaging in glaucoma: optical coherence tomography and retinal nerve fiber layer photography.

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    Kim, Ko Eun; Kim, Seok Hwan; Oh, Sohee; Jeoung, Jin Wook; Suh, Min Hee; Seo, Je Hyun; Kim, Martha; Park, Ki Ho; Kim, Dong Myung

    2014-11-20

    To investigate the additive diagnostic role of spectral-domain optical coherence tomography (SD-OCT) and red-free retinal nerve fiber layer photography (RNFLP) in making clinical glaucoma diagnosis. Four diagnostic combination sets, including the most recent image from each measurement of 196 glaucoma eyes (including the 44 preperimetric glaucoma eyes) and 101 healthy eyes, were prepared: (1) stereo disc photography and Humphrey visual field (SH), (2) SH and SD-OCT (SHO), (3) SH and RNFLP (SHR), and (4) SHR and SD-OCT (SHRO). Each randomly sorted set was serially presented at 1-month intervals to five glaucoma specialists who were asked to evaluate them in a subjective and independent manner. The specialists' glaucoma-diagnostic performances based on the sets were then compared. For each specialist, adding SD-OCT to SH or SHR increased the glaucoma-diagnostic sensitivity but not to a level of statistical significance. For one specialist, adding RNFLP to SH significantly increased the sensitivity. Each specialist showed a high level of specificity regardless of the diagnostic set. The overall sensitivity of all specialists' assessments was significantly increased by adding RNFLP or the combination of SD-OCT and RNFLP to SH (P < 0.001); however, adding SD-OCT to SH or SHR did not significantly increase the sensitivity. A similar relationship was noted also for the preperimetric glaucoma subgroup. In contrast to RNFLP, SD-OCT did not significantly enhance the diagnostic accuracy of detecting glaucoma or even of preperimetric glaucoma. Our results suggest that, at least for glaucoma specialists, the additive diagnostic role of OCT is limited. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  4. Evaluation of Retinal Nerve Fiber Layer Thinning in Myopic Glaucoma: Impact of Optic Disc Morphology.

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    Na, Kyeong Ik; Lee, Won June; Kim, Young Kook; Park, Ki Ho; Jeoung, Jin Wook

    2017-12-01

    The purpose of this study was to investigate the role of optic disc torsion on the rate of progressive retinal nerve fiber layer (RNFL) thinning in patients with myopic open-angle glaucoma. We included 102 patients with myopic open-angle glaucoma accompanied by glaucomatous damage confined to a single hemiretina who were followed up over a 5-year period. We divided the subjects into three groups according to the presence or absence of optic disc torsion and the correspondence between the direction of optic disc torsion and the location of glaucomatous damage: torsion with reverse correspondence group (eyes showing inferior optic disc torsion with glaucomatous damage in the superior quadrant or eyes showing superior torsion with damage in the inferior quadrant), no torsion group, and torsion with correspondence group (eyes showing inferior optic disc torsion with glaucomatous damage in the inferior quadrant or eyes showing superior torsion with damage in the superior quadrant). Changes in the peripapillary RNFL thickness (pRNFLT), evaluated using linear mixed model analysis, were compared among the three groups to determine the relationship between optic disc torsion and pRNFLT changes. Among the total of 102 subjects, 13 eyes (12.7%) exhibited optic disc torsion with reverse correspondence, 59 (57.8%) did not exhibit optic disc torsion, and 30 (29.4%) exhibited optic disc torsion with correspondence. pRNFL thinning in the quadrant with glaucomatous damage was significantly faster in the torsion with correspondence group (-1.66 μm/y) than those in the no torsion (-1.14 μm/y; P = 0.032) and torsion with reverse correspondence (-0.50 μm/y; P optic disc torsion-glaucomatous damage correspondence is an important prognostic factor for patients with myopic open-angle glaucoma.

  5. Are All Retinal Nerve Fiber Layer Defects on Optic Coherence Tomography Glaucomatous?

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    Gür Güngör, Sirel; Ahmet, Akman

    2017-10-01

    In this study, we investigated the patients who were referred to our clinic with a prediagnosis of glaucoma based on retinal nerve fiber layer (RNFL) defects on optic coherence tomography (OCT) but were determined to have nonglaucomatous RNLF defects upon detailed examination. The ophthalmic examination notes, OCT images, Heidelberg retinal tomography (HRT) II and fundus photographs of 357 patients were retrospectively evaluated. Final diagnoses of these patients were investigated. Of the 357 patients, 216 (60.5%) were diagnosed as open angle glaucoma, 33 (9.2%) as low-tension glaucoma, 39 (10.9%) as pre-perimetric glaucoma. The ophthalmic examinations of 14 patients (3.9%) were normal and there were no RNFL defects in OCT examinations after dilatation. In 39 patients (10.9%), the ophthalmic and optic disc examinations were completely normal and no etiologic factor explaining RNFL defects was found. Twenty-two eyes of 16 patients (4.5%) were included in this study (the mean age was 53.8±11.5 years; 9 men and 7 women). After detailed questioning of the medical history and systemic and neurologic examinations, a diagnosis of ischemic optic neuropathy was made in 11 eyes (10 patients) (2.8%), optic neuritis in 3 eyes (2 patients) (0.6%), optic disc drusen in 4 eyes (2 patients) (0.6%), pseudotumor cerebri in 2 eyes (1 patient) (0.3%), and cerebral palsy in 2 eyes (1 patient) (0.3%). Decrease in RNFL thickness on OCT images alone may be misleading in glaucoma examination. In cases where optic disc cupping is not evident, diagnosis should not be based on OCT RNFL examinations alone, and the patient's medical history, detailed ophthalmic examination, OCT optic disc parameters, HRT, and visual field tests should all be carefully evaluated together.

  6. Significant correlations between optic nerve head microcirculation and visual field defects and nerve fiber layer loss in glaucoma patients with myopic glaucomatous disk

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    Yokoyama Y

    2011-12-01

    Full Text Available Yu Yokoyama, Naoko Aizawa, Naoki Chiba, Kazuko Omodaka, Masahiko Nakamura, Takaaki Otomo, Shunji Yokokura, Nobuo Fuse, Toru NakazawaDepartment of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, JapanBackground: Eyes with glaucoma are characterized by optic neuropathy with visual field defects in the areas corresponding to the optic disk damage. The exact cause for the glaucomatous optic neuropathy has not been determined. Myopia has been shown to be a risk factor for glaucoma. The purpose of this study was to determine whether a significant correlation existed between the microcirculation of the optic disk and the visual field defects and the retinal nerve fiber layer thickness (RNFLT in glaucoma patients with myopic optic disks.Methods: Sixty eyes of 60 patients with myopic disks were studied; 36 eyes with glaucoma (men:women = 19:17 and 24 eyes with no ocular diseases (men:women = 14:10. The mean deviation (MD determined by the Humphrey field analyzer, and the peripapillary RNFLT determined by the Stratus-OCT were compared between the two groups. The ocular circulation was determined by laser speckle flowgraphy (LSFG, and the mean blur rate (MBR was compared between the two groups. The correlations between the RNFLT and MBR of the corresponding areas of the optic disk and between MD and MBR of the optic disk in the glaucoma group were determined by simple regression analyses.Results: The average MBR for the entire optic disk was significantly lower in the glaucoma group than that in the control group. The differences of the MBR for the tissue in the superior, inferior, and temporal quadrants of the optic disk between the two groups were significant. The MBR for the entire optic disk was significantly correlated with the MD (r = 0.58, P = 0.0002 and the average RNFLT (r = 0.53, P = 0.0008. The tissue MBR of the optic disk was significantly correlated with the RNFLT in the superior, inferior, and temporal quadrants

  7. Quantification of retinal nerve fiber layer thickness using spectral domain optical coherence tomography in normal Indian population

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    Tarannum Mansoori

    2012-01-01

    Full Text Available The purpose of this study was to measure peripapillary retinal nerve fiber layer thickness (RNFLT using spectral domain optical coherence tomography (SD-OCT in normal Indian eyes, for which, 210 normal volunteers were recruited. One eye of each subject underwent RNFL scanning at 3.4 mm circle diameter around optic nerve using SD OCT. The data were analyzed to determine RNFLT in the sample population and its variation with age and gender. The average peripapillary RNFLT was 114.03 ± 9.59 μm. There was no effect of gender on RNFLT parameters. Age had significant negative correlation with average (P = 0.005, superior (P = 0.04, temporal (P = 0.049, and nasal quadrants (P = 0.01 RNFLT. Inferior quadrant RNFLT also had a negative correlation with age, but it was not statistically significant (P = 0.15.

  8. An artificial arm/hand system with a haptic sensory function using electric stimulation of peripheral sensory nerve fibers.

    Science.gov (United States)

    Mabuchi, Kunihiko

    2013-01-01

    We are currently developing an artificial arm/hand system which is capable of sensing stimuli and then transferring these stimuli to users as somatic sensations. Presently, we are evoking the virtual somatic sensations by electrically stimulating a sensory nerve fiber which innervates a single mechanoreceptor unit at the target area; this is done using a tungsten microelectrode that was percutaneously inserted into the use's peripheral nerve (a microstimulation method). The artificial arm/hand system is composed of a robot hand equipped with a pressure sensor system on its fingers. The sensor system detects mechanical stimuli, which are transferred to the user by means of the microstimulation method so that the user experiences the stimuli as the corresponding somatic sensations. In trials, the system worked satisfactorily and there was a good correlation between the pressure applied to the pressure sensors on the robot fingers and the subjective intensities of the evoked pressure sensations.

  9. The influence of botulinum toxin type A (BTX) on the immunohistochemical characteristics of noradrenergic and cholinergic nerve fibers supplying the porcine urinary bladder wall.

    Science.gov (United States)

    Lepiarczyk, E; Bossowska, A; Kaleczyc, J; Majewski, M

    2011-01-01

    Botulinum toxin (BTX) belongs to a family of neurotoxins which strongly influence the function of autonomic neurons supplying the urinary bladder. Accordingly, BTX has been used as an effective drug in experimental therapies of a range of neurogenic bladder disorders. However, there is no detailed information dealing with the influence of BTX on the morphological and chemical properties of nerve fibres supplying the urinary bladder wall. Therefore, the present study investigated, using double-labeling immunohistochemistry, the distribution, relative frequency and chemical coding of cholinergic and noradrenergic nerve fibers supplying the wall of the urinary bladder in normal female pigs (n = 6) and in the pigs (n = 6) after intravesical BTX injections. In the pigs injected with BTX, the number of adrenergic (DbetaH-positive) nerve fibers distributed in the bladder wall (urothelium, submucosa and muscle coat) was distinctly higher while the number of cholinergic (VAChT-positive) nerve terminals was lower than that found in the control animals. Moreover, the injections of BTX resulted in some changes dealing with the chemical coding of the adrenergic nerve fibers. In contrast to the normal pigs, in BTX injected animals the number of DbetaH/NPY- or DbetaH/CGRP-positive axons was higher in the muscle coat, and some fibres distributed in the urothelium and submucosa expressed immunoreactivity to CGRP. The results obtained suggest that the therapeutic effects of BTX on the urinary bladder might be dependent on changes in the distribution and chemical coding of nerve fibers supplying this organ.

  10. Evaluation of retinal nerve fiber layer thickness parameters in myopic population using scanning laser polarimetry (GDxVCC).

    Science.gov (United States)

    Dada, Tanuj; Aggarwal, A; Bali, S J; Sharma, A; Shah, B M; Angmo, D; Panda, A

    2013-01-01

    Myopia presents a significant challenge to the ophthalmologist as myopic discs are often large, tilted, with deep cups and have a thinner neuroretinal rim all of which may mimic glaucomatous optic nerve head changes causing an error in diagnosis. To evaluate the retinal fiber layer (RNFL) thickness in low, moderate and high myopia using scanning laser polarimetry with variable corneal compensation (GDxVCC). One hundred eyes of 100 emmetropes, 30 eyes of low myopes (0 to - 4 D spherical equivalent(SE), 45 eyes with moderate myopia (- 4 to - 8D SE), and 30 eyes with high myopia (- 8 to - 15D SE) were subjected to retinal nerve fiber layer assessment using the scanning laser polarimetry (GDxVCC) in all subjects using the standard protocol. Subjects with IOP > 21 mm Hg, optic nerve head or visual field changes suggestive of glaucoma were excluded from the study. The major outcome parameters were temporal-superior-nasal-inferiortemporal (TSNIT) average, the superior and inferior average and the nerve fibre indicator (NFI). The TSNIT average (p = 0.009), superior (p = 0.001) and inferior average (p = 0.008) were significantly lower; the NFI was higher (P less than 0.001) in moderate myopes as compared to that in emmetropes. In high myopia the RNFL showed supranormal values; the TSNIT average, superior and inferior average was significantly higher(p less than 0.001) as compared to that in emmetropes. The RNFL measurements on scanning laser polarimetry are affected by the myopic refractive error. Moderate myopes show a significant thinning of the RNFL. In high myopia due to peripapillary chorioretinal atrophy and contribution of scleral birefringence, the RNFL values are abnormally high. These findings need to be taken into account while assessing and monitoring glaucoma damage in moderate to high myopes on GDxVCC. © NEPjOPH.

  11. Hypoxia-induced increases in serotonin-immunoreactive nerve fibers in the medulla oblongata of the rat.

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    Morinaga, Ryosuke; Nakamuta, Nobuaki; Yamamoto, Yoshio

    2016-10-01

    Hypoxia induces respiratory responses in mammals and serotonergic neurons in the medulla oblongata participate in respiratory control. However, the morphological changes in serotonergic neurons induced by hypoxia have not yet been examined and respiratory controls of serotonergic neurons have not been clarified. We herein investigated the distribution of immunoreactivity for serotonin (5-hydroxytryptamine; 5-HT) in the medulla oblongata of control rats and rats exposed to 1-6h of hypoxia (10% O 2 ). We also examined the medulla oblongata by multiple immunofluorescence labeling for 5-HT, neurokinin 1 receptors (NK1R), a marker for some respiratory neurons in the pre-Bötzinger complex (PBC), and dopamine β-hydroxylase (DBH), a marker for catecholaminergic neurons. The number of 5-HT-immunoreactive nerve cell bodies in the raphe nuclei was higher in rats exposed to hypoxia than in control rats. The number of 5-HT-immunoreactive nerve fibers significantly increased in the rostral ventrolateral medulla of rats exposed to 1-6h of hypoxia, caudal ventrolateral medulla of rats exposed to 2-6h of hypoxia, and lateral part of the nucleus of the solitary tract and dorsal motor nucleus of the vagus nerve of rats exposed to 1-2h of hypoxia. Multiple immunofluorescence labeling showed that 5-HT-immunoreactive nerve fibers were close to NK1R-immunoreactive neurons in ventrolateral medulla and to DBH-immunoreactive neurons in the medulla. These results suggest that serotonergic neurons partly regulate respiratory control under hypoxic conditions by modulating the activity of NK1R-expressing and catecholaminergic neurons. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Correlation between local glaucomatous visual field defects and loss of nerve fiber layer thickness measured with polarimetry and spectral domain OCT.

    Science.gov (United States)

    Horn, Folkert K; Mardin, Christian Y; Laemmer, Robert; Baleanu, Delia; Juenemann, Anselm M; Kruse, Friedrich E; Tornow, Ralf P

    2009-05-01

    To study the correlation between local perimetric field defects and glaucoma-induced thickness reduction of the nerve layer measured in the peripapillary area with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with those of a theoretical model. The thickness of the retinal nerve fiber layer was determined in 32 sectors (11.25 degrees each) by using SLP with variable cornea compensation (GDxVCC; Laser Diagnostics, San Diego, CA) and the newly introduced high-resolution SOCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). Eighty-eight healthy subjects served as control subjects, to determine the thickness deviation in patients with glaucoma. The relationship between glaucomatous nerve fiber reduction and visual field losses was calculated in six nerve fiber bundle-related areas. Sixty-four patients at different stages of open-angle glaucoma and 26 patients with ocular hypertension underwent perimetry (Octopus G1; Haag-Streit, Köniz, Switzerland) and measurements with the two morphometric techniques. Sector-shaped analyses between local perimetric losses and reduction of the retinal nerve fiber layer thickness showed a significant association for corresponding areas except for the central visual field in SLP. Correlation coefficients were highest in the area of the nasal inferior visual field (SOCT, -0.81; SLP, -0.57). A linear model describes the association between structural and functional damage. Localized perimetric defects can be explained by reduced nerve fiber layer thickness. The data indicate that the present SOCT is useful for determining the functional-structural relationship in peripapillary areas and that association between perimetric defects and corresponding nerve fiber losses is stronger for SOCT than for the present SLP. (ClinicalTrials.gov number, NCT00494923.).

  13. An Evaluation of Peripapillary Retinal Nerve Fiber Layer Thickness in Children With Epilepsy Receiving Treatment of Valproic Acid.

    Science.gov (United States)

    Dereci, Selim; Koca, Tuğba; Akçam, Mustafa; Türkyilmaz, Kemal

    2015-07-01

    We investigated the peripapillary retinal nerve fiber layer thickness with optical coherence tomography in epileptic children receiving valproic acid monotherapy. The study was conducted on children aged 8-16 years who were undergoing valproic acid monotherapy for epilepsy. The study group comprised a total of 40 children who met the inclusion criteria and 40 healthy age- and sex-matched children as a control group. Children with at least a 1-year history of epilepsy and taking 10-40 mg/kg/day treatment were included in the study. Peripapillary retinal nerve fiber layer thickness measurements were performed using Cirrus HD optical coherence tomography. All children and parents were informed about the study and informed consent was obtained from the parents of all the participants. The study group included 21 girls and 19 boys with a mean age of 10.6 ± 2.3 years. According to the results of optical coherence tomography measurements, the mean peripapillary retinal nerve fiber layer thickness was 91.6 ± 9.7 in the patient group and 95.5 ± 7.4 μm in the control group (P epilepsy who were receiving valproic acid monotherapy compared with healthy children. This situation can lead to undesirable results in terms of eye health. New studies are needed to investigate whether these findings are the result of epilepsy or can be attributed to valproic acid and whether there are adverse effects of valproic acid later in life. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Distribution of serotonergic and dopaminergic nerve fibers in the salivary gland complex of the cockroach Periplaneta americana

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    Kühnel Dana

    2002-06-01

    Full Text Available Abstract Background The cockroach salivary gland consists of secretory acini with peripheral ion-transporting cells and central protein-producing cells, an extensive duct system, and a pair of reservoirs. Salivation is controled by serotonergic and dopaminergic innervation. Serotonin stimulates the secretion of a protein-rich saliva, dopamine causes the production of a saliva without proteins. These findings suggest a model in which serotonin acts on the central cells and possibly other cell types, and dopamine acts selectively on the ion-transporting cells. To examine this model, we have analyzed the spatial relationship of dopaminergic and serotonergic nerve fibers to the various cell types. Results The acinar tissue is entangled in a meshwork of serotonergic and dopaminergic varicose fibers. Dopaminergic fibers reside only at the surface of the acini next to the peripheral cells. Serotonergic fibers invade the acini and form a dense network between central cells. Salivary duct segments close to the acini are locally associated with dopaminergic and serotonergic fibers, whereas duct segments further downstream have only dopaminergic fibers on their surface and within the epithelium. In addition, the reservoirs have both a dopaminergic and a serotonergic innervation. Conclusion Our results suggest that dopamine is released on the acinar surface, close to peripheral cells, and along the entire duct system. Serotonin is probably released close to peripheral and central cells, and at initial segments of the duct system. Moreover, the presence of serotonergic and dopaminergic fiber terminals on the reservoir indicates that the functions of this structure are also regulated by dopamine and serotonin.

  15. Findings of Optical Coherence Tomography of Retinal Nerve Fiber Layer in Two Common Types of Multiple Sclerosis

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    Gholamali Yousefipour

    2016-06-01

    Full Text Available Multiple sclerosis (MS is the most prevalent disease caused by the inflammatory demyelinating process that causes progressive nervous system degeneration over the time. Optical Coherence Tomography (OCT is a non-invasive optical imaging technology, which can measure the thickness of retinal nerve fiber layer as well as the diameter of the macula. The purpose of the study is evaluation OCT findings in two common types of multiple sclerosis. For doing the cross-sectional study, 63 patients with two prevalent types of multiple sclerosis (35 patients with Relapse Remitting Multiple Sclerosis (RRMS and 28 patients with Secondary Progressive Multiple Sclerosis (SPMS were evaluated for 6 months. Exclusion criteria of the study were a history of optic neuritis, suffering from diabetes mellitus, hypertension, ocular disease, and the presence of other neurologic degenerative diseases. Then, the thickness of retinal nerve fiber layer (RNFL, as well as thickness and volume of the macula, were measured in the patients using OCT technology. The disability rate of patients was evaluated according to Expanded Disability Status Scale (EDSS. Finally, data was analyzed by means of SPSS software. Overall, 35 patients with RRMS (with mean age of 32.37+10.01, average disease period of 3.81+3.42 and mean EDSS of 1.84+0.45 and 28 patients with SPMS (with mean age of 39.21+9.33, average disease period of 11.32+5.87 and mean EDSS of 5.12+1.46 were assessed and compared in terms of retinal nerve fiber layer and size and thickness of macula. In all of these sections, the thicknesses were smaller in SPMS patients than patients with RRMS. But, there was a significant difference in total thickness (81.82µm versus 96.03µm with P=0.04 and thickness of temporal sector (54.5 µm versus 69.34 µm with P=0.04 of retinal nerve fiber layer and macular size at the superior sector of external ring (1.48 mm³ versus 1.58 mm³ with P=0.03, and nasal sector of external ring surrounding

  16. Retinal ganglion cell-inner plexiform and nerve fiber layers in neuromyelitis optica

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    Sai-Jing Hu

    2018-01-01

    Full Text Available AIM: To determine the thickness of the retinal ganglion cell-inner plexiform layer (GCIPL and the retinal nerve fiber layer (RNFL in patients with neuromyelitis optica (NMO. METHODS: We conducted a cross-sectional study that included 30 NMO patients with a total of 60 eyes. Based on the presence or absence of optic neuritis (ON, subjects were divided into either the NMO-ON group (30 eyes or the NMO-ON contra group (10 eyes. A detailed ophthalmologic examination was performed for each group; subsequently, the GCIPL and the RNFL were measured using high-definition optical coherence tomography (OCT. RESULTS: In the NMO-ON group, the mean GCIPL thickness was 69.28±21.12 μm, the minimum GCIPL thickness was 66.02±10.02 μm, and the RNFL thickness were 109.33±11.23, 110.47±3.10, 64.92±12.71 and 71.21±50.22 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the NMO-ON contra group, the mean GCIPL thickness was 85.12±17.09 μm, the minimum GCIPL thickness was 25.39±25.1 μm, and the RNFL thicknesses were 148.33±23.22, 126.36±23.45, 82.21±22.30 and 83.36±31.28 μm in the superior, inferior, temporal and nasal quadrants, respectively. In the control group, the mean GCIPL thickness was 86.98±22.37 μm, the minimum GCIPL thickness was 85.28±10.75 μm, and the RNFL thicknesses were 150.22±22.73, 154.79±60.23, 82.33±7.01 and 85.62±13.81 μm in the superior, inferior, temporal and nasal quadrants, respectively. The GCIPL and RNFL were thinner in the NMO-ON contra group than in the control group (P<0.05; additionally, the RNFL was thinner in the inferior quadrant in the NMO-ON group than in the control group (P<0.05. Significant correlations were observed between the GCIPL and RNFL thickness measurements as well as between thickness measurements and the two visual field parameters of mean deviation (MD and corrected pattern standard deviation (PSD in the NMO-ON group (P<0.05. CONCLUSION: The thickness of the GCIPL

  17. Correlation between glycemic control and peripapillary retinal nerve fiber layer thickness in Saudi type II diabetics

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    Fahmy RM

    2018-03-01

    Full Text Available Rania M Fahmy,1,2 Ramesa S Bhat,3 Manar Al-Mutairi,4 Feda S Aljaser,5 Afaf El-Ansary4 1Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia; 2Department of Ophthalmology, Faculty of Medicine, Cairo University, Giza, Egypt; 3Biochemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia; 4Central Laboratory, Female Center for Medical Studies and Scientific Section, King Saud University, Riyadh, Saudi Arabia; 5Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia Objective: To evaluate the effect of diabetes mellitus (DM, diabetic retinopathy, and degree of glycemic control (glycosylated hemoglobin [HbA1c] on peripapillary retinal nerve fiber layer thickness (RNFLT using optical coherence tomography.Methods: The study included 126 eyes of healthy controls (n=32 and diabetics patients (n=31, whose ages ranged from 40 to 70 years. The diabetic group was divided into: Subgroup 1: with HbA1c <7% and Subgroup 2: with HbA1c ≥7%. All patients underwent full ophthalmic examination. HbA1c level was obtained with the A1cNow+ system and the peripapillary RNFLT was measured using 3D-OCT 2000 Topcon (360-degree circular scan with 3.4 mm diameter centered on optic disc.Results: The obtained data demonstrates significant decrease in peripapillary RNFLT in superior and inferior quadrants of the right eye (p=0.000 and p=0.039, respectively, and in superior quadrant of the left eye (p=0.002 with impairment of glycemic control. Pearson’s correlation test showed significant negative correlation of RNFLT with HbA1c in the superior quadrant in both eyes.Conclusion: Impairment of glycemic control affects the peripapillary RNFLT mainly in the superior quadrant. This thickness also tends to decrease with long-standing DM, use of DM medications, and development of diabetic retinopathy. The measurement of peripapillary RNFLT

  18. The human dorsal spinocerebellar tract: myelinated fiber spectrum and fiber density in controls, autosomal dominant spinocerebellar atrophy, Huntington's chorea, radiation myelopathy, and diseases with peripheral sensory nerve involvement

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    Ringelstein, E.B.; Schroeder, J.M.

    1982-01-01

    The human dorsal spinocerebellar tract (DSCT) was evaluated morphometrically in 14 control cases of different age and sex using semithin sections of epon-embedded cross sections from the C3, T5, and T10 segments of the spinal cord. A bimodal fiber spectrum was revealed with one peak at 2-3 microns, and a second, broader peak at about 6-8 microns. Fiber density at C3 was 11,188 fibers/mm2 and at T5, 11,156 fibers/mm2. Regression analysis relating fiber density to age disclosed a highly significant loss of myelinated fibers at T5 amounting to about 2.5% per decade. A severe reduction of fiber density and a distinct change in the fiber spectrum with predominant loss of large myelinated fibers were noted in a case of autosomal dominant spinocerebellar atrophy with late onset, and, to a lesser degree, in a case of Huntington's chorea. A subtotal loss of fibers with a persistent normal distribution of fiber sizes was observed rostral to a focus of severe radiation myelopathy, indicating Wallerian degeneration of large numbers of fibers, and a reduction of fiber diameters caudal to the lesion, suggesting retrograde fiber change. By contrast, no primary or transneural changes in the DSCT were detected in six cases of long-term alcoholism, carcinomatous sensory neuropathy, and neurofibromatosis in spite of the involvement of numerous nerve roots.

  19. Metabolic Changes in the Visual Cortex Are Linked to Retinal Nerve Fiber Layer Thinning in Multiple Sclerosis

    Science.gov (United States)

    Schubert, Florian; Bock, Markus; Walaszek, Bernadeta; Waiczies, Helmar; Schwenteck, Thomas; Dörr, Jan; Bellmann-Strobl, Judith; Mohr, Christian; Weinges-Evers, Nicholetta; Ittermann, Bernd; Wuerfel, Jens T.; Paul, Friedemann

    2011-01-01

    Objective To investigate the damage to the retinal nerve fiber layer as part of the anterior visual pathway as well as an impairment of the neuronal and axonal integrity in the visual cortex as part of the posterior visual pathway with complementary neuroimaging techniques, and to correlate our results to patients' clinical symptoms concerning the visual pathway. Design, Subjects and Methods Survey of 86 patients with relapsing-remitting multiple sclerosis that were subjected to retinal nerve fiber layer thickness (RNFLT) measurement by optical coherence tomography, to a routine MRI scan including the calculation of the brain parenchymal fraction (BPF), and to magnetic resonance spectroscopy at 3 tesla, quantifying N-acetyl aspartate (NAA) concentrations in the visual cortex and normal-appearing white matter. Results RNFLT correlated significantly with BPF and visual cortex NAA, but not with normal-appearing white matter NAA. This was connected with the patients' history of a previous optic neuritis. In a combined model, both BPF and visual cortex NAA were independently associated with RNFLT. Conclusions Our data suggest the existence of functional pathway-specific damage patterns exceeding global neurodegeneration. They suggest a strong interrelationship between damage to the anterior and the posterior visual pathway. PMID:21494672

  20. Spectral Domain Optical Coherence Tomography in Glaucoma: Qualitative and Quantitative Analysis of the Optic Nerve Head and Retinal Nerve Fiber Layer (An AOS Thesis)

    Science.gov (United States)

    Chen, Teresa C.

    2009-01-01

    Purpose: To demonstrate that video-rate spectral domain optical coherence tomography (SDOCT) can qualitatively and quantitatively evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) glaucomatous structural changes. To correlate quantitative SDOCT parameters with disc photography and visual fields. Methods: SDOCT images from 4 glaucoma eyes (4 patients) with varying stages of open-angle glaucoma (ie, early, moderate, late) were qualitatively contrasted with 2 age-matched normal eyes (2 patients). Of 61 other consecutive patients recruited in an institutional setting, 53 eyes (33 patients) met inclusion/exclusion criteria for quantitative studies. Images were obtained using two experimental SDOCT systems, one utilizing a superluminescent diode and the other a titanium:sapphire laser source, with axial resolutions of about 6 μm and 3 μm, respectively. Results: Classic glaucomatous ONH and RNFL structural changes were seen in SDOCT images. An SDOCT reference plane 139 μm above the retinal pigment epithelium yielded cup-disc ratios that best correlated with masked physician disc photography cup-disc ratio assessments. The minimum distance band, a novel SDOCT neuroretinal rim parameter, showed good correlation with physician cup-disc ratio assessments, visual field mean deviation, and pattern standard deviation (P values range, .0003–.024). RNFL and retinal thickness maps correlated well with disc photography and visual field testing. Conclusions: To our knowledge, this thesis presents the first comprehensive qualitative and quantitative evaluation of SDOCT images of the ONH and RNFL in glaucoma. This pilot study provides basis for developing more automated quantitative SDOCT-specific glaucoma algorithms needed for future prospective multicenter national trials. PMID:20126502

  1. Influence of corneal power on circumpapillary retinal nerve fiber layer and optic nerve head measurements by spectral-domain optical coherence tomography

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    Kazunori Hirasawa

    2017-09-01

    Full Text Available AIM: To evaluate the influence of corneal power on circumpapillary retinal nerve fiber layer (cpRNFL and optic nerve head (ONH measurements by spectral-domain optical coherence tomography (SD-OCT. METHODS: Twenty-five eyes of 25 healthy participants (mean age 23.6±3.6y were imaged by SD-OCT using horizontal raster scans. Disposable soft contact lenses of different powers (from −11 to +5 diopters including 0 diopter were worn to induce 2-diopter changes in corneal power. Differences in the cpRNFL and ONH measurements per diopter of change in corneal power were analyzed. RESULTS: As corneal power increased by 1 diopter, total and quadrant cpRNFL thicknesses, except for the nasal sector, decreased by −0.19 to −0.32 μm (P<0.01. Furthermore, the disc, cup, and rim areas decreased by −0.017, −0.007, and −0.015 mm2, respectively (P<0.001; the cup and rim volumes decreased by −0.0013 and −0.006 mm3, respectively (P<0.01; and the vertical and horizontal disc diameters decreased by −0.006 and −0.007 mm, respectively (P<0.001. CONCLUSION: For more precise OCT imaging, the ocular magnification should be corrected by considering both the axial length and corneal power. However, the effect of corneal power changes on cpRNFL thickness and ONH topography are small when compare with those of the axial length.

  2. Does optic nerve head surface topography change prior to loss of retinal nerve fiber layer thickness: a test of the site of injury hypothesis in experimental glaucoma.

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    Brad Fortune

    Full Text Available To test the hypothesis that optic nerve head (ONH deformation manifesting as changes in its mean surface height precedes thinning of the peripapillary retinal nerve fiber layer (RNFL in experimental glaucoma (EG.68 rhesus macaque monkeys each had three or more baseline imaging sessions under manometric intraocular pressure (IOP control to obtain average RNFL thickness (RNFLT and the ONH surface topography parameter mean position of the disc (MPD. Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic, mild-to-moderate IOP elevation and bi-weekly imaging continued. Event analysis was applied to determine for each parameter when an 'endpoint' occurred (signficant change from baseline for eight different endpoint criteria. Specificity was assessed in the group of 68 fellow control eyes. Classical signal detection theory and survival analysis were used to compare MPD with RNFLT.Regardless of the endpoint criterion, endpoints were always more frequent for MPD than for RNFLT. The discriminability index (d' was 2.7 ± 0.2 for MPD and 1.9 ± 0.2 for RNFLT (p<0.0001. Endpoints were reached by MPD an average of 1-2 months earlier than by RNFLT (p<0.01. At the onset of the first specific, detectable MPD change in EG eyes, there was still no significant change in RNFLT on average (p=0.29 and only 25% of individual eyes exhibited signficant reduction. In contrast, at onset of signficant RNFLT change, MPD had already changed an average of 101 µm from baseline (p<0.0001 and 71% of the individual eyes had exhibited significant change. The magnitude of MPD change was more than could be explained on the basis of axon loss alone.This study demonstrates that the average surface height of the ONH changes prior to any detectable loss of average peripapillary RNFL thickness in non-human primate eyes with experimental glaucoma.

  3. Optic Nerve Head and Retinal Nerve Fiber Layer Analysis in Ocular Hypertension and Early-Stage Glucoma Using Spectral-Domain Optical Coherence Tomography Copernicus

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    Nilgün Solmaz

    2014-01-01

    Full Text Available Objectives: Evaluation of structural alterations of the optic nerve head (ONH and the retinal nerve fiber layer (RNFL in patients with ocular hypertension (OHT and early-stage glaucoma and assessment of the discriminatory diagnostic performance of spectral-domain optical coherence tomography (SD-OCT Copernicus (Optopol Technology S.A.. Materials and Methods: This study included 59 eyes of a total of 59 patients, 29 of whom were diagnosed with OHT (Group 1 and 30 with early-stage glaucoma (Group 2. The differentiation of early-stage glaucoma and OHT was carried out on the basis of standard achromatic visual field test results. Analysis of the ONH and RNFL thickness of all cases was made using SD-OCT. Group 1 and Group 2 were compared with respect to the ONH parameters and RNFL thickness. The diagnostic sensitivity of the OCT parameters was evaluated by the area under the receiver operating characteristics curves (AUC. Results: The average, superior, inferior, and nasal RNFL thicknesses in early-stage glaucoma cases were approximately 10% (12-14 µm less compared to the OHT eyes, with differences being highly significant (p≤0.001. However, there was no statistically significant difference in the temporal RNFL thicknesses. The most sensitive parameter in the early diagnosis of glaucoma was average RNFL thickness corresponding to AUC: 0.852, followed by AUC: 0.816 and AUC: 0.773 values in superior and inferior RNFL thickness, respectively. In localized RNFL defects, the highest sensitivity corresponded to superior and superonasal quadrants (ACU: 0.805 and ACU: 0.781, respectively. There were not any statistically significant differences between the ONH morphological parameters of the two groups. Conclusion: RNFL analysis obtained using SD-OCT Copernicus is able to discriminate early-stage glaucoma eyes from those with OHT. However, ONH morphological parameters do not have the same diagnostic sensitivity. Turk J Ophthalmol 2014; 44: 35-41

  4. Incorporation of parallel electrospun fibers for improved topographical guidance in 3D nerve guides

    International Nuclear Information System (INIS)

    Jeffries, Eric M; Wang Yadong

    2013-01-01

    Three dimensional (3D) conduits facilitate nerve regeneration. Parallel microfibers have been shown to guide axon extension and Schwann cell migration on flat sheets via topographical cues. However, incorporation of aligned microfibers into 3D conduits to accelerate nerve regeneration has proven challenging. We report an electrospinning technique to incorporate parallel microfibers into 3D constructs at high surface areas while retaining an open architecture. The nerve guide consists of many microchannels lined with a thin layer of longitudinally-aligned microfibers. This design aims to maximize benefits of topographical cues without inhibiting cellular infiltration. We support this hypothesis by demonstrating efficient cell infiltration in vitro. Additionally, this new technique reduces wall thickness compared to our previous design, providing a greater total area for tissue growth. This approach results in an architecture that very closely mimics the structure of decellularized nerve but with larger microchannel diameters to encourage cell infiltration. We believe that reproducing the native architecture is the first step toward matching autograph efficacy. Furthermore, this design can be combined with other biochemical cues to promote nerve regeneration. (paper)

  5. Optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy in retinal nerve fiber layer measurements of glaucoma patients.

    Science.gov (United States)

    Fanihagh, Farsad; Kremmer, Stephan; Anastassiou, Gerasimos; Schallenberg, Maurice

    2015-01-01

    To determine the correlations and strength of association between different imaging systems in analyzing the retinal nerve fiber layer (RNFL) of glaucoma patients: optical coherence tomography (OCT), scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (CSLO). 114 eyes of patients with moderate open angle glaucoma underwent spectral domain OCT (Topcon SD-OCT 2000 and Zeiss Cirrus HD-OCT), SLP (GDx VCC and GDx Pro) and CSLO (Heidelberg Retina Tomograph, HRT 3). Correlation coefficients were calculated between the structural parameters yielded by these examinations. The quantitative relationship between the measured RNFL thickness globally and for the four regions (superior, inferior, nasal, temporal) were evaluated with different regression models for all used imaging systems. The strongest correlation of RNFL measurements was found between devices using the same technology like GDx VCC and GDx Pro as well as Topcon OCT and Cirrus OCT. In glaucoma patients, the strongest associations (R²) were found between RNFL measurements of the two optical coherence tomography devices Topcon OCT and Cirrus OCT (R² = 0.513) and between GDx VCC and GDx Pro (R² = 0.451). The results of the OCTs and GDX Pro also had a strong quantitative relationship (Topcon OCT R² = 0.339 and Cirrus OCT R² = 0.347). GDx VCC and the OCTs showed a mild to moderate association (Topcon OCT R² = 0.207 and Cirrus OCT R² = 0.258). The confocal scanning laser ophthalmoscopy (HRT 3) had the lowest association to all other devices (Topcon OCT R² = 0.254, Cirrus OCT R² = 0.158, GDx Pro R² = 0.086 and GDx VCC R² = 0.1). The measurements of the RNFL in glaucoma patients reveal a high correlation of OCT and GDx devices because OCTs can measure all major retinal layers and SLP can detect nerve fibers allowing a comparison between the results of this devices. However, CSLO by means of HRT topography can only measure height values of the retinal surface but it cannot distinguish

  6. Spatiotemporal dynamics of re-innervation and hyperinnervation patterns by uninjured CGRP fibers in the rat foot sole epidermis after nerve injury

    NARCIS (Netherlands)

    L.S. Duraku (Liron); S.M. Hossaini (Mehdi); S. Hoendervangers (Sieske); H.E. Falke; S. Kambiz (Shoista); V. Mudera (Vivek); J.C. Holstege (Jan); E.T. Walbeehm (Erik); T.J.H. Ruigrok (Tom)

    2012-01-01

    textabstractThe epidermis is innervated by fine nerve endings that are important in mediating nociceptive stimuli. However, their precise role in neuropathic pain is still controversial. Here, we have studied the role of epidermal peptidergic nociceptive fibers that are located adjacent to injured

  7. Spatiotemporal dynamics of re-innervation and hyperinnervation patterns by uninjured CGRP fibers in the rat foot sole epidermis after nerve injury

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    Duraku Liron S

    2012-08-01

    Full Text Available Abstract The epidermis is innervated by fine nerve endings that are important in mediating nociceptive stimuli. However, their precise role in neuropathic pain is still controversial. Here, we have studied the role of epidermal peptidergic nociceptive fibers that are located adjacent to injured fibers in a rat model of neuropathic pain. Using the Spared Nerve Injury (SNI model, which involves complete transections of the tibial and common peroneal nerve while sparing the sural and saphenous branches, mechanical hypersensitivity was induced of the uninjured lateral (sural and medial (saphenous area of the foot sole. At different time points, a complete foot sole biopsy was taken from the injured paw and processed for Calcitonin Gene-Related Peptide (CGRP immunohistochemistry. Subsequently, a novel 2D-reconstruction model depicting the density of CGRP fibers was made to evaluate the course of denervation and re-innervation by uninjured CGRP fibers. The results show an increased density of uninjured CGRP-IR epidermal fibers on the lateral and medial side after a SNI procedure at 5 and 10 weeks. Furthermore, although in control animals the density of epidermal CGRP-IR fibers in the footpads was lower compared to the surrounding skin of the foot, 10 weeks after the SNI procedure, the initially denervated footpads displayed a hyper-innervation. These data support the idea that uninjured fibers may play a considerable role in development and maintenance of neuropathic pain and that it is important to take larger biopsies to test the relationship between innervation of injured and uninjured nerve areas.

  8. FIBER-OPTIC BIOSENSOR FOR DIRECT DETERMINATION OF ORGANOPHOSPHATE NERVE AGENTS. (R823663)

    Science.gov (United States)

    A fiber-optic enzyme biosensor for the direct measurement of organophosphate nerveagents was developed. The basic element of this biosensor is organophosphorus hydrolaseimmobilized on a nylon membrane and attached to the common end of a bifurcated optical fiberbundle....

  9. Effect of cochlear nerve electrocautery on the adult cochlear nucleus.

    Science.gov (United States)

    Iseli, Claire E; Merwin, William H; Klatt-Cromwell, Cristine; Hutson, Kendall A; Ewend, Matthew G; Adunka, Oliver F; Fitzpatrick, Douglas C; Buchman, Craig A

    2015-04-01

    Electrocauterization and subsequent transection of the cochlear nerve induce greater injury to the cochlear nucleus than sharp transection alone. Some studies show that neurofibromatosis Type 2 (NF2) patients fit with auditory brainstem implants (ABIs) fail to achieve speech perception abilities similar to ABI recipients without NF2. Reasons for these differences remain speculative. One hypothesis posits poorer performance to surgically induced trauma to the cochlear nucleus from electrocautery. Sustained electrosurgical depolarization of the cochlear nerve may cause excitotoxic-induced postsynaptic nuclear injury. Equally plausible is that cautery in the vicinity of the cochlear nucleus induces necrosis. The cochlear nerve was transected in anesthetized adult gerbils sharply with or without bipolar electrocautery at varying intensities. Gerbils were perfused at 1, 3, 5, and 7 days postoperatively; their brainstem and cochleas were embedded in paraffin and sectioned at 10 μm. Alternate sections were stained with flourescent markers for neuronal injury or Nissl substance. In additional experiments, anterograde tracers were applied directly to a sectioned eighth nerve to verify that fluorescent-labeled profiles seen were terminating auditory nerve fibers. Cochlear nerve injury was observed from 72 hours postoperatively and was identical across cases regardless of surgical technique. Postsynaptic cochlear nucleus injury was not seen after distal transection of the nerve. By contrast, proximal transection was associated with trauma to the cochlear nucleus. Distal application of bipolar electrocautery seems safe for the cochlear nucleus. Application near the root entry zone must be used cautiously because this may compromise nuclear viability needed to support ABI stimulation.

  10. Analysis of visual appearance of retinal nerve fibers in high resolution fundus images: a study on normal subjects.

    Science.gov (United States)

    Kolar, Radim; Tornow, Ralf P; Laemmer, Robert; Odstrcilik, Jan; Mayer, Markus A; Gazarek, Jiri; Jan, Jiri; Kubena, Tomas; Cernosek, Pavel

    2013-01-01

    The retinal ganglion axons are an important part of the visual system, which can be directly observed by fundus camera. The layer they form together inside the retina is the retinal nerve fiber layer (RNFL). This paper describes results of a texture RNFL analysis in color fundus photographs and compares these results with quantitative measurement of RNFL thickness obtained from optical coherence tomography on normal subjects. It is shown that local mean value, standard deviation, and Shannon entropy extracted from the green and blue channel of fundus images are correlated with corresponding RNFL thickness. The linear correlation coefficients achieved values 0.694, 0.547, and 0.512 for respective features measured on 439 retinal positions in the peripapillary area from 23 eyes of 15 different normal subjects.

  11. Analysis of Visual Appearance of Retinal Nerve Fibers in High Resolution Fundus Images: A Study on Normal Subjects

    Directory of Open Access Journals (Sweden)

    Radim Kolar

    2013-01-01

    Full Text Available The retinal ganglion axons are an important part of the visual system, which can be directly observed by fundus camera. The layer they form together inside the retina is the retinal nerve fiber layer (RNFL. This paper describes results of a texture RNFL analysis in color fundus photographs and compares these results with quantitative measurement of RNFL thickness obtained from optical coherence tomography on normal subjects. It is shown that local mean value, standard deviation, and Shannon entropy extracted from the green and blue channel of fundus images are correlated with corresponding RNFL thickness. The linear correlation coefficients achieved values 0.694, 0.547, and 0.512 for respective features measured on 439 retinal positions in the peripapillary area from 23 eyes of 15 different normal subjects.

  12. Effect of cataract surgery on retinal nerve fiber layer thickness parameters using scanning laser polarimetry (GDxVCC).

    Science.gov (United States)

    Dada, Tanuj; Behera, Geeta; Agarwal, Anand; Kumar, Sanjeev; Sihota, Ramanjit; Panda, Anita

    2010-01-01

    To study the effect of cataract extraction on the retinal nerve fiber layer (RNFL) thickness, and assessment by scanning laser polarimetry (SLP), with variable corneal compensation (GDx VCC), at the glaucoma service of a tertiary care center in North India. Thirty-two eyes of 32 subjects were enrolled in the study. The subjects underwent RNFL analysis by SLP (GDx VCC) before undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation (Acrysof SA 60 AT) four weeks following cataract surgery. The RNFL thickness parameters evaluated both before and after surgery included temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and nerve fiber index (NFI). The mean age of subjects was 57.6 +/- 11.7 years (18 males, 14 females). Mean TSNIT average thickness (microm) pre- and post-cataract surgery was 49.2 +/- 14.1 and 56.5 +/- 7.6 ( P = 0.001). There was a statistically significant increase in RNFL thickness parameters (TSNIT average, superior average, and inferior average) and decrease in NFI post-cataract surgery as compared to the baseline values. Mean NFI pre- and post-cataract surgery was 41.3 +/- 15.3 and 21.6 +/- 11.8 ( P = 0.001). Measurement of RNFL thickness parameters by scanning laser polarimetry is significantly altered following cataract surgery. Post the cataract surgery, a new baseline needs to be established for assessing the longitudinal follow-up of a glaucoma patient. The presence of cataract may lead to an underestimation of the RNFL thickness, and this should be taken into account when analyzing progression in a glaucoma patient.

  13. Correlation between peripapillary retinal nerve fiber layer thickness and fundus autofluorescence in primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Reznicek L

    2013-09-01

    Full Text Available Lukas Reznicek,* Florian Seidensticker,* Thomas Mann, Irene Hübert, Alexandra Buerger, Christos Haritoglou, Aljoscha S Neubauer, Anselm Kampik, Christoph Hirneiss, Marcus Kernt Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany *These authors contributed equally to this work Purpose: To investigate the relationship between retinal nerve fiber layer (RNFL thickness and retinal pigment epithelium alterations in patients with advanced glaucomatous visual field defects. Methods: A consecutive, prospective series of 82 study eyes with primary open-angle glaucoma and advanced glaucomatous visual field defects were included in this study. All study participants underwent a full ophthalmic examination followed by visual field testing with standard automated perimetry as well as spectral-domain optical coherence tomography (SD-OCT for peripapillary RNFL thickness and Optos wide-field fundus autofluorescence (FAF images. A pattern grid with corresponding locations between functional visual field sectors and structural peripapillary RNFL thickness was aligned to the FAF images at corresponding location. Mean FAF intensity (range: 0 = black and 255 = white of each evaluated sector (superotemporal, temporal, inferotemporal, inferonasal, nasal, superonasal was correlated with the corresponding peripapillary RNFL thickness obtained with SD-OCT. Results: Correlation analyses between sectoral RNFL thickness and standardized FAF intensity in the corresponding topographic retina segments revealed partly significant correlations with correlation coefficients ranging between 0.004 and 0.376 and were statistically significant in the temporal inferior central field (r = 0.324, P = 0.036 and the nasal field (r = 0.376, P = 0.014. Conclusion: Retinal pigment epithelium abnormalities correlate with corresponding peripapillary RNFL damage, especially in the temporal inferior sector of patients with advanced glaucomatous visual field defects. A

  14. High-resolution imaging of the retinal nerve fiber layer in normal eyes using adaptive optics scanning laser ophthalmoscopy.

    Science.gov (United States)

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Arakawa, Naoko; Oshima, Susumu; Shibata, Naohisa; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2012-01-01

    To conduct high-resolution imaging of the retinal nerve fiber layer (RNFL) in normal eyes using adaptive optics scanning laser ophthalmoscopy (AO-SLO). AO-SLO images were obtained in 20 normal eyes at multiple locations in the posterior polar area and a circular path with a 3-4-mm diameter around the optic disc. For each eye, images focused on the RNFL were recorded and a montage of AO-SLO images was created. AO-SLO images for all eyes showed many hyperreflective bundles in the RNFL. Hyperreflective bundles above or below the fovea were seen in an arch from the temporal periphery on either side of a horizontal dividing line to the optic disc. The dark lines among the hyperreflective bundles were narrower around the optic disc compared with those in the temporal raphe. The hyperreflective bundles corresponded with the direction of the striations on SLO red-free images. The resolution and contrast of the bundles were much higher in AO-SLO images than in red-free fundus photography or SLO red-free images. The mean hyperreflective bundle width around the optic disc had a double-humped shape; the bundles at the temporal and nasal sides of the optic disc were narrower than those above and below the optic disc (Poptical coherence tomography correlated with the hyperreflective bundle widths on AO-SLO (Pfiber bundles and Müller cell septa. The widths of the nerve fiber bundles appear to be proportional to the RNFL thickness at equivalent distances from the optic disc.

  15. Association between retinal nerve fiber layer thickness and magnetic resonance imaging findings and intelligence in patients with multiple sclerosis.

    Science.gov (United States)

    Ashtari, Fereshteh; Emami, Parisa; Akbari, Mojtaba

    2015-01-01

    Multiple Sclerosis (MS) is a neurological disease in which demyelination and axonal loss leads to progressive disability. Cognition impairment is among the most common complication. Studying axonal loss in the retina is a new marker for MS. The main goal of our study is to search for correlations between magnetic resonance imaging (MRI) findings and the retinal nerve fiber layer (RNFL) thickness at the macula and head of the optic nerve and Wechsler Adult Intelligence Scale-Revised (WAIS-R) Scores that assess multiple domains of intelligence, and to explore the relationship between changes in the RNFL thickness with intellectual and cognitive dysfunction. A prospective cross-sectional study was conducted at the University Hospital of Kashani, Isfahan, Iran, from September to December 2013. All patients were assessed with a full-scale intelligence quotient (IQ) on the WAIS-R. An optical coherence tomography study and brain MRI were performed in the same week for all the patients. Statistical analysis was conducted by using a bivariate correlation, by utilizing SPSS 20.0. A P value ≤ 0.05 was the threshold of statistical significance. Examination of a 100 patients showed a significant correlation between the average RNFL thickness of the macula and the verbal IQ (P value = 0.01) and full IQ (P value = 0.01). There was a significant correlation between brain atrophy and verbal IQ. The RNFL loss was correlated with verbal IQ and full IQ.

  16. Interocular symmetry of retinal nerve fiber layer and optic nerve head parameters measured by Cirrus high-definition optical coherence tomography in a normal pediatric population.

    Science.gov (United States)

    Pawar, Neelam; Maheshwari, Devendra; Ravindran, Meenakshi; Ramakrishnan, Renagappa

    2017-10-01

    To determine interocular differences in the retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters in a pediatric population using Cirrus high-definition optical coherence tomography (HD-OCT). Seventy normal Indian children aged 5-17 years presenting to the Pediatric Clinic were included in this observational cross-sectional study. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the RNFL and ONH by Cirrus HD-OCT. Differences between the right and left eyes were calculated and values were compared by means of a paired t-test. Subjects were also divided into two groups based on age (under or over 10 years of age). Interocular differences in RNFL and ONH parameters together with sex and age variations for these differences were determined. The mean age of studied pediatric population was 11.83 ± 3.3 years (range 5-17). Average RNFL thickness was 94.46 ± 8.7 μm (± SD) (range 77-111). Differences in the average RNFL between right and left eyes were not statistically significant (P = 0.060). Superior quadrant RNFL was thicker in the left eye and temporal quadrant was thicker in the right eye. Among ONH parameters, there were no statistically significant differences in any parameters, except vertical cup-disc (CD) ratio which was significant (P = 0.007). The 2.5%-97.5% limits of asymmetry were 9 μm for average RNFL, 0.14 for average CD ratio, and 0.22 for vertical CD ratio. Mean interocular RNFL thickness differences in superior, superior nasal, and temporal superior quadrants were 10.61 (P sex, while only significant differences with age were observed in 12 clock hour sector analysis, mainly in nasal inferior and inferior quadrant. We report the degree of interocular symmetry of RNFL and ONH parameters measured by Cirrus HD-OCT in a healthy pediatric population. The normal interocular RNFL asymmetry should not exceed 9 μm and vertical CD ratio beyond 0.22 should be considered for further investigations. The

  17. The effect of aging on efferent nerve fibers regeneration in mice.

    Science.gov (United States)

    Verdú, E; Butí, M; Navarro, X

    1995-10-23

    This study evaluates the influence of aging on nerve regeneration and reinnervation of target organs in mice aged 2, 6, 9, 12, 18 and 24 months. In animals of each age group the sciatic nerve was subjected to crush, section or section and suture. Reinnervation of plantar muscles and sweat glands (SG) was evaluated over three months after operation by functional methods. Reappearance of SG secretion and motor responses occurred slightly earlier in young than older mice. The degree of motor and sudomotor reinnervation, with respect to preoperative control values, was also significantly higher in young than old animals. The differences were more pronounced after 12 months of age. The degree of recovery progressively decreased with the severity of the lesion, differences being more marked in older mice. Neurorraphy improved recovery, comparatively more in older than in young mice. These results indicate that, after injuries of peripheral nerves, axonal regeneration and reinnervation are maintained throughout life, but tend to be more delayed and slightly less effective with aging.

  18. Functional and structural nerve fiber findings in heterozygote patients with Fabry disease

    DEFF Research Database (Denmark)

    Torvin, Moller A.; Winther, Bach F.; Feldt-Rasmussen, U.

    2009-01-01

    recently disease manifestations in female carriers of Fabry disease have been questioned. To explore the frequency of symptoms and the functional and structural involvement of the nervous system in female patients we examined the presence of pain, manifestations of peripheral neuropathy and nerve density......Fabry disease is an X-linked inherited lysosomal disorder with dysfunction of the lysosomal enzyme alpha-galactosidase A causing accumulation of glycolipids in multiple organs including the nervous system. Pain and somatosensory disturbances are prominent manifestations of this disease. Until...

  19. Neurophysiological approach to disorders of peripheral nerve

    DEFF Research Database (Denmark)

    Crone, Clarissa; Krarup, Christian

    2013-01-01

    Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves......, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological...

  20. Abnormal Auditory Gain in Hyperacusis: Investigation with a Computational Model

    Directory of Open Access Journals (Sweden)

    Peter U. Diehl

    2015-07-01

    Full Text Available Hyperacusis is a frequent auditory disorder that is characterized by abnormal loudness perception where sounds of relatively normal volume are perceived as too loud or even painfully loud. As Hyperacusis patients show decreased loudness discomfort levels (LDLs and steeper loudness growth functions, it has been hypothesized that hyperacusis might be caused by an increase in neuronal response gain in the auditory system. Moreover, since about 85% of hyperacusis patients also experience tinnitus, the conditions might be caused by a common mechanism. However, the mechanisms that give rise to hyperacusis have remained unclear.Here we have used a computational model of the auditory system to investigate candidate mechanisms for hyperacusis. Assuming that perceived loudness is proportional to the summed activity of all auditory nerve fibers, the model was tuned to reproduce normal loudness perception. We then evaluated a variety of potential hyperacusis gain mechanisms by determining their effects on model equal-loudness contours and comparing the results to the LDLs of hyperacusis patients with normal hearing thresholds. Hyperacusis was best accounted for by an increase in nonlinear gain in the central auditory system. Good fits to the average patient LDLs were obtained for a general increase in gain that affected all frequency channels to the same degree, and also for a frequency-specific gain increase in the high-frequency range. Moreover, the gain needed to be applied after subtraction of spontaneous activity of the auditory nerve, which is in contrast to current theories of tinnitus generation based on amplification of spontaneous activity. Hyperacusis and tinnitus might therefore be caused by different changes in neuronal processing in the central auditory system.

  1. Retinal Nerve Fiber Layer Thickness Changes in the Pseudoexfoliation Syndrome: A Meta-Analysis of Case-Control Studies.

    Science.gov (United States)

    Yu, Ji-Guo; Huang, Qing; Zhou, Xiao-Fang; Ding, Yi; Li, Jing; Xiang, Yi

    2018-01-01

    To evaluate and compare changes in retinal nerve fiber layer (RNFL) thickness in patients with the pseudoexfoliation syndrome (PXS) and healthy controls. Case-control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PubMed, and Embase. Results were reviewed to ensure that the included studies met prespecified inclusion/exclusion criteria, and the quality of each study was assessed using the Newcastle-Ottawa Scale. All included studies measured average and 4-quadrant (temporal, superior, nasal, and inferior) RNFL thickness using optical coherence tomography (OCT). For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence intervals (CIs). Eight case-control studies were included in this meta-analysis involving 225 eyes of PXS patients and 208 eyes of healthy controls in total. Statistical analysis revealed that the average RNFL thickness in PXS patients was significantly reduced compared to healthy controls (WMD = -6.91, 95% CI: -9.99 to -3.82, p < 0.0001). Additionally, differences in RNFL thickness in the superior quadrant (WMD = -10.68, 95% CI: -16.40 to -4.95, p = 0.0003), inferior quadrant (WMD = -8.20, 95% CI: -10.85 to -5.55, p < 0.00001), nasal quadrant (WMD = -3.05, 95% CI: -5.21 to -0.90, p = 0.005), and temporal quadrant (WMD = -6.39, 95% CI: -9.98 to -2.80, p = 0.0005) were all significant between the two groups. These results suggest that it is important to evaluate RNFL thickness and the optic nerve head through OCT in patients with PXS in order to determine early glaucomatous damage and start timely intervention prior to visual field loss. © 2017 S. Karger AG, Basel.

  2. Macular Ganglion Cell Inner Plexiform Layer Thickness in Glaucomatous Eyes with Localized Retinal Nerve Fiber Layer Defects.

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    Chunwei Zhang

    Full Text Available To investigate macular ganglion cell-inner plexiform layer (mGCIPL thickness in glaucomatous eyes with visible localized retinal nerve fiber layer (RNFL defects on stereophotographs.112 healthy and 149 glaucomatous eyes from the Diagnostic Innovations in Glaucoma Study (DIGS and the African Descent and Glaucoma Evaluation Study (ADAGES subjects had standard automated perimetry (SAP, optical coherence tomography (OCT imaging of the macula and optic nerve head, and stereoscopic optic disc photography. Masked observers identified localized RNFL defects by grading of stereophotographs.47 eyes had visible localized RNFL defects on stereophotographs. Eyes with visible localized RNFL defects had significantly thinner mGCIPL thickness compared to healthy eyes (68.3 ± 11.4 μm versus 79.2 ± 6.6 μm respectively, P<0.001 and similar mGCIPL thickness to glaucomatous eyes without localized RNFL defects (68.6 ± 11.2 μm, P = 1.000. The average mGCIPL thickness in eyes with RNFL defects was 14% less than similarly aged healthy controls. For 29 eyes with a visible RNFL defect in just one hemiretina (superior or inferior mGCIPL was thinnest in the same hemiretina in 26 eyes (90%. Eyes with inferior-temporal RNFL defects also had significantly thinner inferior-temporal mGCIPL (P<0.001 and inferior mGCIPL (P = 0.030 compared to glaucomatous eyes without a visible RNFL defect.The current study indicates that presence of a localized RNFL defect is likely to indicate significant macular damage, particularly in the region of the macular that topographically corresponds to the location of the RNFL defect.

  3. Perimetric measurements with flicker-defined form stimulation in comparison with conventional perimetry and retinal nerve fiber measurements.

    Science.gov (United States)

    Horn, Folkert K; Tornow, Ralf P; Jünemann, Anselm G; Laemmer, Robert; Kremers, Jan

    2014-04-11

    We compared the results of flicker-defined form (FDF) perimetry with standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) thickness measurements using spectral domain optical coherence tomography (OCT). A total of 64 healthy subjects, 45 ocular hypertensive patients, and 97 "early" open-angle glaucoma (OAG) patients participated in this study. Definition of glaucoma was based exclusively on glaucomatous optic disc appearance. All subjects underwent FDF perimetry, SAP, and peripapillary measurements of the RNFL thickness. The FDF perimetry and SAP were performed at identical test locations (G1 protocol). Exclusion criteria were subjects younger than 34 years, SAP mean defect (SAP MD) > 5 dB, eye diseases other than glaucoma, or nonreliable FDF measurements. The correlations between the perimetric data on one hand and RNFL thicknesses on the other hand were analyzed statistically. The age-corrected sensitivity values and the local results from the controls were used to determine FDF mean defect (FDF MD). The FDF perimetry and SAP showed high concordance in this cohort of experienced patients (MD values, R = -0.69, P < 0.001). Of a total of 42 OAG patients with abnormal SAP MD, 38 also displayed abnormal FDF MD. However, FDF MD was abnormal in 28 of 55 OAG patients with normal SAP MD. The FDF MD was significantly (R = -0.61, P < 0.001) correlated with RNFL thickness with a (nonsignificantly) larger correlation coefficient than conventional SAP MD (R = -0.48, P < 0.001). The FDF perimetry is able to uncover functional changes concurrent with the changes in RNFL thickness. The FDF perimetry may be an efficient functional test to detect early glaucomatous nerve atrophy. (ClinicalTrials.gov number, NCT00494923.).

  4. Relevance Vector Machine and Support Vector Machine Classifier Analysis of Scanning Laser Polarimetry Retinal Nerve Fiber Layer Measurements

    Science.gov (United States)

    Bowd, Christopher; Medeiros, Felipe A.; Zhang, Zuohua; Zangwill, Linda M.; Hao, Jiucang; Lee, Te-Won; Sejnowski, Terrence J.; Weinreb, Robert N.; Goldbaum, Michael H.

    2010-01-01

    Purpose To classify healthy and glaucomatous eyes using relevance vector machine (RVM) and support vector machine (SVM) learning classifiers trained on retinal nerve fiber layer (RNFL) thickness measurements obtained by scanning laser polarimetry (SLP). Methods Seventy-two eyes of 72 healthy control subjects (average age = 64.3 ± 8.8 years, visual field mean deviation =−0.71 ± 1.2 dB) and 92 eyes of 92 patients with glaucoma (average age = 66.9 ± 8.9 years, visual field mean deviation =−5.32 ± 4.0 dB) were imaged with SLP with variable corneal compensation (GDx VCC; Laser Diagnostic Technologies, San Diego, CA). RVM and SVM learning classifiers were trained and tested on SLP-determined RNFL thickness measurements from 14 standard parameters and 64 sectors (approximately 5.6° each) obtained in the circumpapillary area under the instrument-defined measurement ellipse (total 78 parameters). Tenfold cross-validation was used to train and test RVM and SVM classifiers on unique subsets of the full 164-eye data set and areas under the receiver operating characteristic (AUROC) curve for the classification of eyes in the test set were generated. AUROC curve results from RVM and SVM were compared to those for 14 SLP software-generated global and regional RNFL thickness parameters. Also reported was the AUROC curve for the GDx VCC software-generated nerve fiber indicator (NFI). Results The AUROC curves for RVM and SVM were 0.90 and 0.91, respectively, and increased to 0.93 and 0.94 when the training sets were optimized with sequential forward and backward selection (resulting in reduced dimensional data sets). AUROC curves for optimized RVM and SVM were significantly larger than those for all individual SLP parameters. The AUROC curve for the NFI was 0.87. Conclusions Results from RVM and SVM trained on SLP RNFL thickness measurements are similar and provide accurate classification of glaucomatous and healthy eyes. RVM may be preferable to SVM, because it provides a

  5. Retinal nerve fiber layer analysis with scanning laser polarimetry and RTVue-OCT in patients of retinitis pigmentosa.

    Science.gov (United States)

    Xue, Kang; Wang, Min; Chen, Junyi; Huang, Xin; Xu, Gezhi

    2013-01-01

    To measure the thickness of the retinal nerve fiber layer (RNFL) of patients with retinitis pigmentosa (RP) and that of normal controls by scanning laser polarimetry with enhanced corneal compensation (GDxECC) and RTVue-optical coherence tomography (OCT). Fifty-two eyes of 26 patients were included. All patients underwent complete ophthalmological examinations and testing with GDxECC. Twenty-eight of 52 eyes of RP patients underwent RTVue-OCT measurements. A group of 50 eyes of 25 normal subjects (controls) was also included. GDxECC measured RNFL thickness in the peripapillary area in all subjects as well as temporal-superior-nasal-inferior-temporal (TSNIT) parameters, including TSNIT means, superior and inferior region means, TSNIT standard deviation (SD), inter-eye symmetry and nerve fiber indicator (NFI). RTVue-OCT measured the mean, superior, inferior, temporal and nasal quadrant RNFL thickness. In RP patients and controls, TSNIT means by GDxECC were, respectively, 65.00 ± 7.35 and 55.32 ± 5.20. Mean superior quadrant thicknesses were 80.56 ± 10.93 and 69.54 ± 7.45. Mean inferior thicknesses were 80.58 ± 9.34 and 69.12 ± 7.78. SDs were 27.92 ± 5.21 and 28.23 ± 4.01. Inter-eye symmetries were 0.82 ± 0.17 and 0.87 ± 0.09. NFIs were 9.74 ± 8.73 and 16.81 ± 8.13. The differences between mean TSNIT, mean superior and mean inferior quadrant thicknesses and NFIs were statistically significant (p < 0.001). In RTVue-OCT measurements, the differences between mean, superior, inferior and temporal quadrant RNFL thicknesses were statistically significant (p = 0.0322, 0.0213, 0.0387, 0.0005). The RNFL measured by GDxECC was significantly thicker in RP patients than in controls. RNFL thickness measured by RTVue-OCT was significantly greater in RP patients than in controls in the superior, inferior and temporal regions. This contribution provides information on RNFL thickness and discusses the mechanism underlying this phenomenon. Copyright © 2012 S. Karger AG

  6. Hypodense regions (holes) in the retinal nerve fiber layer in frequency-domain OCT scans of glaucoma patients and suspects.

    Science.gov (United States)

    Xin, Daiyan; Talamini, Christine L; Raza, Ali S; de Moraes, Carlos Gustavo V; Greenstein, Vivienne C; Liebmann, Jeffrey M; Ritch, Robert; Hood, Donald C

    2011-09-09

    To better understand hypodense regions (holes) that appear in the retinal nerve fiber layer (RNFL) of frequency-domain optical coherence tomography (fdOCT) scans of patients with glaucoma and glaucoma suspects. Peripapillary circle (1.7-mm radius) and cube optic disc fdOCT scans were obtained on 208 eyes from 110 patients (57.4 ± 13.2 years) with glaucomatous optic neuropathy (GON) and 45 eyes of 45 controls (48.0 ± 12.6 years) with normal results of fundus examination. Holes in the RNFL were identified independently by two observers on the circle scans. Holes were found in 33 (16%) eyes of 28 (25%) patients; they were not found in any of the control eyes. Twenty-four eyes had more than one hole. Although some holes were relatively large, others were small. In general, the holes were located adjacent to blood vessels; only three eyes had isolated holes that were not adjacent to a vessel. The holes tended to be in the regions that are thickest in healthy controls and were associated with arcuate defects in patients. Holes were not seen in the center of the temporal disc region. They were more common in the superior (25 eyes) than in the inferior (15 eyes) disc. Of the 30 eyes with holes with reliable visual fields, seven were glaucoma suspect eyes with normal visual fields. The holes in the RNFL seen in patients with GON were probably due to a local loss of RNFL fibers and can occur in the eyes of glaucoma suspects with normal visual fields.

  7. Confocal Cornea Microscopy Detects Involvement of Corneal Nerve Fibers in a Patient with Light-Chain Amyloid Neuropathy Caused by Multiple Myeloma: A Case Report

    Directory of Open Access Journals (Sweden)

    Dietrich Sturm

    2016-06-01

    Full Text Available Changes in the subbasal corneal plexus detected by confocal cornea microscopy (CCM have been described for various types of neuropathy. An involvement of these nerves within light-chain (AL amyloid neuropathy (a rare cause of polyneuropathy has never been shown. Here, we report on a case of a patient suffering from neuropathy caused by AL amyloidosis and underlying multiple myeloma. Small-fiber damage was detected by CCM.

  8. Radioanatomy of the singular nerve canal

    Energy Technology Data Exchange (ETDEWEB)

    Muren, C. [Dept. of Diagnostic Radiology, Sabbatsbergs Hospital, Stockholm (Sweden); Wadin, K. [University Hospital, Uppsala (Sweden); Dimopoulos, P. [University Hospital, Uppsala (Sweden)

    1991-08-01

    The singular canal conveys vestibular nerve fibers from the ampulla of the posterior semicircular canal to the posteroinferior border of the internal auditory meatus. Radiographic identification of this anatomic structure helps to distinguish it from a fracture. It is also a landmark in certain surgical procedures. Computed tomography (CT) examinations of deep-frozen temporal bone specimens were compared with subsequently prepared plastic casts of these bones, showing good correlation between the anatomy and the images. The singular canal and its variable anatomy were studied in CT examinations of 107 patients. The singular canal could be identified, in both the axial and in the coronal planes. Its point of entry into the internal auditory meatus varied considerably. (orig.)

  9. Age and Glaucoma-Related Characteristics in Retinal Nerve Fiber Layer and Choroid: Localized Morphometrics and Visualization Using Functional Shapes Registration

    Directory of Open Access Journals (Sweden)

    Sieun Lee

    2017-07-01

    Full Text Available Optical coherence tomography provides high-resolution 3D imaging of the posterior segment of the eye. However, quantitative morphological analysis, particularly relevant in retinal degenerative diseases such as glaucoma, has been confined to simple sectorization and averaging with limited spatial sensitivity for detection of clinical markers. In this paper, we present point-wise analysis and visualization of the retinal nerve fiber layer and choroid from cross-sectional data using functional shapes (fshape registration. The fshape framework matches two retinas, or generates a mean of multiple retinas, by jointly optimizing the surface geometry and functional signals mapped on the surface. We generated group-wise mean retinal nerve fiber layer and choroidal surfaces with the respective layer thickness mapping and showed the difference by age (normal, younger vs. older and by disease (age-matched older, normal vs. glaucomatous in the two layers, along with a more conventional sector-based analysis for comparison. The fshape results visualized the detailed spatial patterns of the differences between the age-matched normal and glaucomatous retinal nerve fiber layers, with the glaucomatous layers most significantly thinner in the inferior region close to Bruch's membrane opening. Between the young and older normal cases, choroid was shown to be significantly thinner in the older subjects across all regions, but particularly in the nasal and inferior regions. The results demonstrate a comprehensive and detailed analysis with visualization of morphometric patterns by multiple factors.

  10. Automatic computer-aided diagnosis of retinal nerve fiber layer defects using fundus photographs in optic neuropathy.

    Science.gov (United States)

    Oh, Ji Eun; Yang, Hee Kyung; Kim, Kwang Gi; Hwang, Jeong-Min

    2015-05-01

    To evaluate the validity of an automatic computer-aided diagnosis (CAD) system for detection of retinal nerve fiber layer (RNFL) defects on fundus photographs of glaucomatous and nonglaucomatous optic neuropathy. We have proposed an automatic detection method for RNFL defects on fundus photographs in various cases of glaucomatous and nonglaucomatous optic neuropathy. In order to detect the vertical dark bands as candidate RNFL defects, the nonuniform illumination of the fundus image was corrected, the blood vessels were removed, and the images were converted to polar coordinates with the center of the optic disc. False positives (FPs) were reduced by using knowledge-based rules. The sensitivity and FP rates for all images were calculated. We tested 98 fundus photographs with 140 RNFL defects and 100 fundus photographs of healthy normal subjects. The proposed method achieved a sensitivity of 90% and a 0.67 FP rate per image and worked well with RNFL defects with variable depths and widths, with uniformly high detection rates regardless of the angular widths of the RNFL defects. The average detection accuracy was approximately 0.94. The overall diagnostic accuracy of the proposed algorithm for detecting RNFL defects among 98 patients and 100 healthy individuals was 86% sensitivity and 75% specificity. The proposed CAD system successfully detected RNFL defects in optic neuropathies. Thus, the proposed algorithm is useful for the detection of RNFL defects.

  11. Ability of spectral domain optical coherence tomography peripapillary retinal nerve fiber layer thickness measurements to identify early glaucoma

    Directory of Open Access Journals (Sweden)

    Tarannum Mansoori

    2011-01-01

    Full Text Available Purpose : To evaluate the ability of spectral domain optical coherence tomography (OCT peripapillary retinal nerve fiber layer thickness (RNFLT parameters to distinguish normal eyes from those with early glaucoma in Asian Indian eyes. Design : Observational cross-sectional study. Materials and Methods : One hundred and seventy eight eyes (83 glaucoma patients and 95 age matched healthy subjects of subjects more than 40 years of age were included in the study. All subjects underwent RNFLT measurement with spectral OCT/ scanning laser ophthalmoscope (SLO after dilatation. Sensitivity, specificity and area under the receiving operating characteristic curve (AROC were calculated for various OCT peripapillary RNFL parameters. Results: The mean RNFLT in healthy subjects and patients with early glaucoma were 105.7 ± 5.1 μm and 90.7 ± 7.5 μm, respectively. The largest AROC was found for 12 o′clock- hour (0.98, average (0.96 and superior quadrant RNFLT (0.9. When target specificity was set at ≥ 90% and ≥ 80%, the parameters with highest sensitivity were 12 o′clock -hour (91.6%, average RNFLT (85.3% and 12 o′ clock- hour (96.8 %, average RNFLT (94.7% respectively. Conclusion : Our study showed good ability of spectral OCT/ SLO to differentiate normal eyes from patients with early glaucoma and hence it may serve as an useful adjunct for early diagnosis of glaucoma.

  12. Reproducibility of retinal nerve fiber layer thickness measures using eye tracking in children with nonglaucomatous optic neuropathy.

    Science.gov (United States)

    Rajjoub, Raneem D; Trimboli-Heidler, Carmelina; Packer, Roger J; Avery, Robert A

    2015-01-01

    To determine the intra- and intervisit reproducibility of circumpapillary retinal nerve fiber layer (RNFL) thickness measures using eye tracking-assisted spectral-domain optical coherence tomography (SD OCT) in children with nonglaucomatous optic neuropathy. Prospective longitudinal study. Circumpapillary RNFL thickness measures were acquired with SD OCT using the eye-tracking feature at 2 separate study visits. Children with normal and abnormal vision (visual acuity ≥ 0.2 logMAR above normal and/or visual field loss) who demonstrated clinical and radiographic stability were enrolled. Intra- and intervisit reproducibility was calculated for the global average and 9 anatomic sectors by calculating the coefficient of variation and intraclass correlation coefficient. Forty-two subjects (median age 8.6 years, range 3.9-18.2 years) met inclusion criteria and contributed 62 study eyes. Both the abnormal and normal vision cohort demonstrated the lowest intravisit coefficient of variation for the global RNFL thickness. Intervisit reproducibility remained good for those with normal and abnormal vision, although small but statistically significant increases in the coefficient of variation were observed for multiple anatomic sectors in both cohorts. The magnitude of visual acuity loss was significantly associated with the global (ß = 0.026, P < .01) and temporal sector coefficient of variation (ß = 0.099, P < .01). SD OCT with eye tracking demonstrates highly reproducible RNFL thickness measures. Subjects with vision loss demonstrate greater intra- and intervisit variability than those with normal vision. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Glaucomatous retinal nerve fiber layer thickness loss is associated with slower reaction times under a divided attention task.

    Science.gov (United States)

    Tatham, Andrew J; Boer, Erwin R; Rosen, Peter N; Della Penna, Mauro; Meira-Freitas, Daniel; Weinreb, Robert N; Zangwill, Linda M; Medeiros, Felipe A

    2014-11-01

    To examine the relationship between glaucomatous structural damage and ability to divide attention during simulated driving. Cross-sectional observational study. Hamilton Glaucoma Center, University of California San Diego. Total of 158 subjects from the Diagnostic Innovations in Glaucoma Study, including 82 with glaucoma and 76 similarly aged controls. Ability to divide attention was investigated by measuring reaction times to peripheral stimuli (at low, medium, or high contrast) while concomitantly performing a central driving task (car following or curve negotiation). All subjects had standard automated perimetry (SAP) and optical coherence tomography was used to measure retinal nerve fiber layer (RNFL) thickness. Cognitive ability was assessed using the Montreal Cognitive Assessment and subjects completed a driving history questionnaire. Reaction times to the driving simulator divided attention task. The mean reaction times to the low-contrast stimulus were 1.05 s and 0.64 s in glaucoma and controls, respectively, during curve negotiation (P divide attention, RNFL thickness measurements provided additional information. Information from structural tests may improve our ability to determine which patients are likely to have problems performing daily activities, such as driving. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. PERIPAPILLARY RETINAL NERVE FIBER THICKNESS CHANGES AFTER VITRECTOMY FOR EPIRETINAL MEMBRANE IN EYES WITH AND WITHOUT VITREOUS DETACHMENT.

    Science.gov (United States)

    Mariotti, Cesare; Nicolai, Michele; Longo, Antonio; Viti, Francesca; Bambini, Elisa; Saitta, Andrea; Pirani, Vittorio; Orsini, Emanuele; Baruffa, Daniela; Reibaldi, Michele

    2017-12-01

    To compare the changes in postoperative peripapillary retinal nerve fiber layer (p-RNFL) thickness after vitrectomy for epiretinal membrane in eyes with preexisting posterior vitreous detachment (PVD) and eyes with surgically induced PVD. This study included consecutive patients who underwent 25-gauge vitrectomy for epiretinal membrane. Eyes were divided, according to intraoperative PVD status, into a preexisting PVD group and surgically induced PVD group. Best-corrected visual acuity, p-RNFL thickness, and central retinal thickness were performed before and at 1, 3, and 6 months after surgery. One hundred and twenty eyes of 120 patients were enrolled: 64 eyes in the preexisting PVD group and 56 eyes in the surgically induced PVD group. In the preexisting PVD group at 6 months, the mean global p-RNFL thickness did not change, whereas it was reduced in the temporal sector (P = 0.034). In the surgically induced PVD group at 6 months, significant decreases were observed in global p-RNFL thickness (P = 0.027), temporal (P = 0.021), temporal inferior (P = 0.030), and nasal inferior sectors (P = 0.010). At 6 months, the two groups differed significantly in temporal (P PVD.

  15. Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

    Science.gov (United States)

    Lee, Jong Eun; Sung, Kyung Rim; Park, Ji Min; Yoon, Joo Young; Kang, Sung Yong; Park, Sung Bae; Koo, Hyung Jin

    2017-03-01

    To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia. Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD. Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7 years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.

  16. Optical coherence tomography detection of characteristic retinal nerve fiber layer thinning in nasal hypoplasia of the optic disc.

    Science.gov (United States)

    Haruta, M; Kodama, R; Yamakawa, R

    2017-12-01

    PurposeTo determine the clinical usefulness of optical coherence tomography (OCT) for detecting thinning of the retinal nerve fiber layer (RNFL) in eyes with nasal hypoplasia of the optic discs (NHOD).Patients and methodsThe medical records of five patients (eight eyes) with NHOD were reviewed. The ratio of the disc-macula distance to the disc diameter (DM/DD) and the disc ovality ratio of the minimal to maximal DD were assessed using fundus photographs. The RNFL thicknesses of the temporal, superior, nasal, and inferior quadrants were evaluated using OCT quadrant maps.ResultsAll eight eyes had temporal visual field defects that respected the vertical meridians that needed to be differentiated from those related to chiasmal compression. The mean DM/DD ratio was 3.1 and the mean disc ovality ratio was 0.81. The mean RNFL thicknesses of the temporal, superior, nasal, and inferior quadrants were 90.3, 103.1, 34.8, and 112.8 microns, respectively.ConclusionSmall optic discs and tilted discs might be associated with NHOD. Measurement of the RNFL thickness around the optic disc using OCT scans clearly visualized the characteristic RNFL thinning of the nasal quadrants corresponding to the temporal sector visual field defects in eyes with NHOD. OCT confirmed the presence of NHOD and might differentiate eyes with NHOD from those with chiasmal compression.

  17. A Model-Based Approach for Separating the Cochlear Microphonic from the Auditory Nerve Neurophonic in the Ongoing Response Using Electrocochleography

    Directory of Open Access Journals (Sweden)

    Tatyana E. Fontenot

    2017-10-01

    Full Text Available Electrocochleography (ECochG is a potential clinically valuable technique for predicting speech perception outcomes in cochlear implant (CI recipients, among other uses. Current analysis is limited by an inability to quantify hair cell and neural contributions which are mixed in the ongoing part of the response to low frequency tones. Here, we used a model based on source properties to account for recorded waveform shapes and to separate the combined signal into its components. The model for the cochlear microphonic (CM was a sinusoid with parameters for independent saturation of the peaks and the troughs of the responses. The model for the auditory nerve neurophonic (ANN was the convolution of a unit potential and population cycle histogram with a parameter for spread of excitation. Phases of the ANN and CM were additional parameters. The average cycle from the ongoing response was the input, and adaptive fitting identified CM and ANN parameters that best reproduced the waveform shape. Test datasets were responses recorded from the round windows of CI recipients, from the round window of gerbils before and after application of neurotoxins, and with simulated signals where each parameter could be manipulated in isolation. Waveforms recorded from 284 CI recipients had a variety of morphologies that the model fit with an average r2 of 0.97 ± 0.058 (standard deviation. With simulated signals, small systematic differences between outputs and inputs were seen with some variable combinations, but in general there were limited interactions among the parameters. In gerbils, the CM reported was relatively unaffected by the neurotoxins. In contrast, the ANN was strongly reduced and the reduction was limited to frequencies of 1,000 Hz and lower, consistent with the range of strong neural phase-locking. Across human CI subjects, the ANN contribution was variable, ranging from nearly none to larger than the CM. Development of this model could provide a

  18. Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

    DEFF Research Database (Denmark)

    Mehraei, Golbarg; Paredes Gallardo, Andreu; Shinn-Cunningham, Barbara G.

    2017-01-01

    -spontaneous rate fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker......-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low...

  19. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  20. Representation of acoustic signals in the eighth nerve of the Tokay gecko: I. Pure tones.

    Science.gov (United States)

    Sams-Dodd, F; Capranica, R R

    1994-06-01

    A systematic study of the encoding properties of 146 auditory nerve fibers in the Tokay gecko (Gekko gecko, L) was conducted with respect to pure tones and two-tone rate suppression. Our aim was a comprehensive understanding of the peripheral encoding of simple tonal stimuli and their representation by temporal synchronization and spike rate codes as a prelude to subsequent studies of more complex signals. Auditory nerve fibers in the Tokay gecko have asymmetrical, V-shaped excitatory tuning curves with best excitatory frequencies that range from 200-5100 Hz and thresholds between 4-35 dB SPL. A low-frequency excitatory 'tail' extends far into the low-frequency range and two-tone suppression is present only on the high frequency side of the tuning curve. The response properties to pure tones at different loci within a tuning curve can differ greatly, due to evident interactions between the representations of temporal, spectral and intensity stimulus features. For frequencies below 1250 Hz, pure tones are encoded by both temporal synchronization and spike rate codes, whereas above this frequency a fiber's ability to encode the waveform periodicity is lost and only a rate code predominates. These complimentary representations within a tuning curve raise fundamental issues which need to be addressed in interpreting how more complex, bioacoustic communication signals are represented in the peripheral and central auditory system. And since auditory nerve fibers in the Tokay gecko exhibit tonal sensitivity, selective frequency tuning, and iso-intensity and iso-frequency contours that seem comparable to similar measures in birds and mammals, these issues likely apply to most higher vertebrates in general. The simpler wiring diagram of the reptilian auditory system, coupled with the Tokay gecko's remarkable vocalizations, make this animal a good evolutionary model in which to experimentally explore the encoding of more complex sounds of communicative significance.

  1. Factors Associated with the Retinal Nerve Fiber Layer Loss after Acute Primary Angle Closure: A Prospective EDI-OCT Study.

    Directory of Open Access Journals (Sweden)

    Eun Ji Lee

    Full Text Available To determine the factors associated with retinal nerve fiber layer (RNFL loss in eyes with acute primary angle-closure (APAC, particularly focusing on the influence of the change in the anterior lamina cribrosa surface depth (LCD.After the initial presentation, 30 eyes with unilateral APAC were followed up at the following specific time points over a 12-month period: 1 week, 1~2 months, 2~3 months, 5~6 months, and 11~12 months. These follow-ups involved intraocular pressure measurements, enhanced depth-imaging spectral-domain optical coherence tomography (SD-OCT scanning of the optic disc, and measurements of the circumpapillary RNFL thickness. The prelaminar tissue thickness (PLT and LCD were determined in the SD-OCT images obtained at each follow-up visit.Repeated measures analysis of variance revealed a significant pattern of decrease in the global RNFL thickness, PLT, and LCD (all p<0.001. The global RNFL thickness decreased continuously throughout the follow-up period, while the PLT decreased until 5~6 months and did not change thereafter. The LCD reduced until 2~3 months and then also remained steady. Multivariable regression analysis revealed that symptoms with a longer duration before receiving laser peripheral iridotomy (LI (p = 0.049 and a larger LCD reduction (p = 0.034 were significant factors associated with the conversion to an abnormal RNFL thickness defined using OCT normative data.Early short-term decreases in the PLT and LCD and overall long-term decrease in the peripapillary RNFL were observed during a 12-month follow-up after an APAC episode. A longer duration of symptoms before receiving LI treatment and larger LCD reduction during follow-up were associated with the progressive RNFL loss. The LCD reduction may indicate a prior presence of significant pressure-induced stress that had been imposed on the optic nerve head at the time of APAC episode. Glaucomatous progression should be suspected in eyes showing LCD reduction

  2. 142 Key words: Brachialis, radial nerve, musculocutaneous nerve.

    African Journals Online (AJOL)

    AWORI KIRSTEEN

    The innervation of brachialis muscle by the musculocutaneous nerve has been described as either type I or type II and the main trunk to this muscle is rarely absent. The contribution .... brachialis muscle by fiber analysis of supply nerves].

  3. Magnetic resonance imaging of the internal auditory canal

    International Nuclear Information System (INIS)

    Daniels, D.L.; Herfkins, R.; Koehler, P.R.; Millen, S.J.; Shaffer, K.A.; Williams, A.L.; Haughton, V.M.

    1984-01-01

    Three patients with exclusively or predominantly intracanalicular neuromas and 5 with presumably normal internal auditory canals were examined with prototype 1.4- or 1.5-tesla magnetic resonance (MR) scanners. MR images showed the 7th and 8th cranial nerves in the internal auditory canal. The intracanalicular neuromas had larger diameter and slightly greater signal strength than the nerves. Early results suggest that minimal enlargement of the nerves can be detected even in the internal auditory canal

  4. Glaucoma progression detection by retinal nerve fiber layer measurement using scanning laser polarimetry: event and trend analysis.

    Science.gov (United States)

    Moon, Byung Gil; Sung, Kyung Rim; Cho, Jung Woo; Kang, Sung Yong; Yun, Sung-Cheol; Na, Jung Hwa; Lee, Youngrok; Kook, Michael S

    2012-06-01

    To evaluate the use of scanning laser polarimetry (SLP, GDx VCC) to measure the retinal nerve fiber layer (RNFL) thickness in order to evaluate the progression of glaucoma. Test-retest measurement variability was determined in 47 glaucomatous eyes. One eye each from 152 glaucomatous patients with at least 4 years of follow-up was enrolled. Visual field (VF) loss progression was determined by both event analysis (EA, Humphrey guided progression analysis) and trend analysis (TA, linear regression analysis of the visual field index). SLP progression was defined as a reduction of RNFL exceeding the predetermined repeatability coefficient in three consecutive exams, as compared to the baseline measure (EA). The slope of RNFL thickness change over time was determined by linear regression analysis (TA). Twenty-two eyes (14.5%) progressed according to the VF EA, 16 (10.5%) by VF TA, 37 (24.3%) by SLP EA and 19 (12.5%) by SLP TA. Agreement between VF and SLP progression was poor in both EA and TA (VF EA vs. SLP EA, k = 0.110; VF TA vs. SLP TA, k = 0.129). The mean (±standard deviation) progression rate of RNFL thickness as measured by SLP TA did not significantly differ between VF EA progressors and non-progressors (-0.224 ± 0.148 µm/yr vs. -0.218 ± 0.151 µm/yr, p = 0.874). SLP TA and EA showed similar levels of sensitivity when VF progression was considered as the reference standard. RNFL thickness as measurement by SLP was shown to be capable of detecting glaucoma progression. Both EA and TA of SLP showed poor agreement with VF outcomes in detecting glaucoma progression.

  5. Detection of Progressive Retinal Nerve Fiber Layer Loss in Glaucoma Using Scanning Laser Polarimetry with Variable Corneal Compensation

    Science.gov (United States)

    Medeiros, Felipe A.; Alencar, Luciana M.; Zangwill, Linda M.; Bowd, Christopher; Vizzeri, Gianmarco; Sample, Pamela A.; Weinreb, Robert N.

    2010-01-01

    Purpose To evaluate the ability of scanning laser polarimetry with variable corneal compensation to detect progressive retinal nerve fiber layer (RNFL) loss in glaucoma patients and patients suspected of having the disease. Methods This was an observational cohort study that included 335 eyes of 195 patients. Images were obtained annually with the GDx VCC scanning laser polarimeter, along with optic disc stereophotographs and standard automated perimetry (SAP) visual fields. The median follow-up time was 3.94 years. Progression was determined using commercial software for SAP and by masked assessment of optic disc stereophotographs performed by expert graders. Random coefficient models were used to evaluate the relationship between RNFL thickness measurements over time and progression as determined by SAP and/or stereophotographs. Results From the 335 eyes, 34 (10%) showed progression over time by stereophotographs and/or SAP. Average GDx VCC measurements decreased significantly over time for both progressors as well as non-progressors. However, the rate of decline was significantly higher in the progressing group (−0.70 μm/year) compared to the non-progressing group (−0.14 μm/year; P = 0.001). Black race and male sex were significantly associated with higher rates of RNFL loss during follow-up. Conclusions The GDx VCC scanning laser polarimeter was able to identify longitudinal RNFL loss in eyes that showed progression in optic disc stereophotographs and/or visual fields. These findings suggest that this technology could be useful to detect and monitor progressive disease in patients with established diagnosis of glaucoma or suspected of having the disease. PMID:19029038

  6. Normative spectral domain optical coherence tomography data on macular and retinal nerve fiber layer thickness in Indians

    Directory of Open Access Journals (Sweden)

    Bindu Appukuttan

    2014-01-01

    Full Text Available Aim: To provide the normative data of macular and retinal nerve fiber layer (RNFL thickness in Indians using spectral domain OCT (Spectralis OCT, Heidelberg Engineering, Germany and to evaluate the effects of age, gender, and refraction on these parameters. Design: Observational, cross-sectional study. Materials and Methods: The eyes of 105 healthy patients aged between 20-75 years, with no ocular disease and best corrected visual acuity of 20/20, were scanned using standard scanning protocols by a single examiner. Exclusion criteria included glaucoma, retinal diseases, diabetes, history of prior intraocular surgery or laser treatment. The mean macular and RNFL thickness were recorded, and the effects of age, gender, and refraction on these parameters were evaluated. This data was compared with published literature on Caucasians to assess the ethnic variations of these parameters. Results: The normal central foveal thickness in healthy Indian eyes measured using Spectralis OCT was 260.1 ± 18.19 ΅m. The nasal inner quadrant showed maximum retinal thickness (338.88 ± 18.17 ΅m.The mean RNFL thickness was 101.43 ± 8.63 ΅m with maximum thickness in the inferior quadrant. The central foveal thickness showed a gender-based difference (P = 0.005 but did not correlate significantly with age (P = 0.134, whereas the parafoveal, perifoveal thickness, macular volume, and RNFL thickness showed significant negative correlation with age. Conclusions: Our study provides the normative database for Indians on Spectralis OCT. It also suggests that age should be considered while interpreting the macular thickness and RNFL, whereas gender should also be given consideration in central foveal thickness.

  7. Visual field defects and retinal nerve fiber imaging in patients with obstructive sleep apnea syndrome and in healthy controls.

    Science.gov (United States)

    Casas, Paula; Ascaso, Francisco J; Vicente, Eugenio; Tejero-Garcés, Gloria; Adiego, María I; Cristóbal, José A

    2018-03-02

    To assess the retinal sensitivity in obstructive sleep apnea hypopnea syndrome (OSAHS) patients evaluated with standard automated perimetry (SAP). And to correlate the functional SAP results with structural parameters obtained with optical coherence tomography (OCT). This prospective, observational, case-control study consisted of 63 eyes of 63 OSAHS patients (mean age 51.7 ± 12.7 years, best corrected visual acuity ≥20/25, refractive error less than three spherical or two cylindrical diopters, and intraocular pressure < 21 mmHg) who were enrolled and compared with 38 eyes of 38 age-matched controls. Peripapillary retinal nerve fiber layer (RNFL) thickness was measured by Stratus OCT and SAP sensitivities and indices were explored with Humphrey Field Analyzer perimeter. Correlations between functional and structural parameters were calculated, as well as the relationship between ophthalmologic and systemic indices in OSAHS patients. OSAHS patients showed a significant reduction of the sensitivity for superior visual field division (p = 0.034, t-student test). When dividing the OSAHS group in accordance with the severity of the disease, nasal peripapillary RNFL thickness was significantly lower in severe OSAHS than that in controls and mild-moderate cases (p = 0.031 and p = 0.016 respectively, Mann-Whitney U test). There were no differences between groups for SAP parameters. We found no correlation between structural and functional variables. The central visual field sensitivity of the SAP revealed a poor Pearson correlation with the apnea-hipopnea index (0.284, p = 0.024). Retinal sensitivity show minor differences between healthy subjects and OSAHS. Functional deterioration in OSAHS patients is not easy to demonstrate with visual field examination.

  8. Adaptive optics imaging of healthy and abnormal regions of retinal nerve fiber bundles of patients with glaucoma.

    Science.gov (United States)

    Chen, Monica F; Chui, Toco Y P; Alhadeff, Paula; Rosen, Richard B; Ritch, Robert; Dubra, Alfredo; Hood, Donald C

    2015-01-08

    To better understand the nature of glaucomatous damage of the macula, especially the structural changes seen between relatively healthy and clearly abnormal (AB) retinal regions, using an adaptive optics scanning light ophthalmoscope (AO-SLO). Adaptive optics SLO images and optical coherence tomography (OCT) vertical line scans were obtained on one eye of seven glaucoma patients, with relatively deep local arcuate defects on the 10-2 visual field test in one (six eyes) or both hemifields (one eye). Based on the OCT images, the retinal nerve fiber (RNF) layer was divided into two regions: (1) within normal limits (WNL), relative RNF layer thickness within mean control values ±2 SD; and (2) AB, relative thickness less than -2 SD value. As seen on AO-SLO, the pattern of AB RNF bundles near the border of the WNL and AB regions differed across eyes. There were normal-appearing bundles in the WNL region of all eyes and AB-appearing bundles near the border with the AB region. This region with AB bundles ranged in extent from a few bundles to the entire AB region in the case of one eye. All other eyes had a large AB region without bundles. However, in two of these eyes, a few bundles were seen within this region of otherwise missing bundles. The AO-SLO images revealed details of glaucomatous damage that are difficult, if not impossible, to see with current OCT technology. Adaptive optics SLO may prove useful in following progression in clinical trials, or in disease management, if AO-SLO becomes widely available and easy to use. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  9. Localized Retinal Nerve Fiber Layer Defects in Red-free Photographs Versus En Face Structural Optical Coherence Tomography Images.

    Science.gov (United States)

    Jung, Jae Hoon; Park, Ji-Hye; Yoo, Chungkwon; Kim, Yong Yeon

    2018-03-01

    The purpose of this article is to compare the locations of localized retinal nerve fiber layer (RNFL) defects in red-free fundus photographs and optical coherence tomography (OCT) en face images. We performed a retrospective, comparative study on 46 eyes from 46 glaucoma patients with localized RNFL defects observed in red-free fundus photographs. En face structural images were obtained in the superficial and whole retinal layers using OCT and were overlaid on the corresponding red-free fundus photographs. The proximal/distal angular locations and angular width of each RNFL defect in red-free photos (red-free defects) and in en face structural images (en face defects) were compared. In the superficial retinal layer, there were no significant differences between red-free and en face defects on the proximal/distal angular location and angular width. In the whole retinal layer, the degree of the distal angular location of the en face defects was significantly larger than that of the red-free defects (71.85±18.26 vs. 70.87±17.90 degrees, P=0.003). The correlations of clinical variables with the differences in angular parameters between red-free and en face defects were not significant in the superficial retinal layer. The average RNFL thickness was negatively correlated with the difference in the distal angular location in the whole retinal layer (Pearson correlation coefficient=-0.401, P=0.006). Localized RNFL defects detected in OCT en face structural images of the superficial retinal layer showed high topographic correlation with defects detected in red-free photographs. OCT en face structural images in the superficial layer may be an alternative to red-free fundus photography for the identification of localized RNFL defects in glaucomatous eyes.

  10. Confocal Adaptive Optics Imaging of Peripapillary Nerve Fiber Bundles: Implications for Glaucomatous Damage Seen on Circumpapillary OCT Scans.

    Science.gov (United States)

    Hood, Donald C; Chen, Monica F; Lee, Dongwon; Epstein, Benjamin; Alhadeff, Paula; Rosen, Richard B; Ritch, Robert; Dubra, Alfredo; Chui, Toco Y P

    2015-04-01

    To improve our understanding of glaucomatous damage as seen on circumpapillary disc scans obtained with frequency-domain optical coherence tomography (fdOCT), fdOCT scans were compared to images of the peripapillary retinal nerve fiber (RNF) bundles obtained with an adaptive optics-scanning light ophthalmoscope (AO-SLO). The AO-SLO images and fdOCT scans were obtained on 6 eyes of 6 patients with deep arcuate defects (5 points ≤-15 db) on 10-2 visual fields. The AO-SLO images were montaged and aligned with the fdOCT images to compare the RNF bundles seen with AO-SLO to the RNF layer thickness measured with fdOCT. All 6 eyes had an abnormally thin (1% confidence limit) RNF layer (RNFL) on fdOCT and abnormal (hyporeflective) regions of RNF bundles on AO-SLO in corresponding regions. However, regions of abnormal, but equal, RNFL thickness on fdOCT scans varied in appearance on AO-SLO images. These regions could be largely devoid of RNF bundles (5 eyes), have abnormal-appearing bundles of lower contrast (6 eyes), or have isolated areas with a few relatively normal-appearing bundles (2 eyes). There also were local variations in reflectivity of the fdOCT RNFL that corresponded to the variations in AO-SLO RNF bundle appearance. Relatively similar 10-2 defects with similar fdOCT RNFL thickness profiles can have very different degrees of RNF bundle damage as seen on fdOCT and AO-SLO. While the results point to limitations of fdOCT RNFL thickness as typically analyzed, they also illustrate the potential for improving fdOCT by attending to variations in local intensity.

  11. Optic Disc and Retinal Nerve Fiber Layer Thickness Evaluation of the Fellow Eyes in Non-Arteritic Ischemic Optic Neuropathy

    Directory of Open Access Journals (Sweden)

    Medine Yılmaz Dağ

    2015-05-01

    Full Text Available Objectives: To examine the fellow eyes in unilateral non-arteritic ischemic optic neuropathy (NAION and to compare their optic disc parameters and peripapillary retinal nerve fiber layer (RNFL thickness with age-and refraction-matched normal controll subjects, using Heidelberg Retinal Tomograph 2 (HRT II. Materials and Methods: The fellow eyes of 40 patients with typical unilateral NAION (study group and one randomly chosen eye of 42 age-, sex-, and refraction-matched normal control subjects were enrolled in the study. Optic disc morphologic features (average disc area, cup area, rim area, disc volume, rim volume, cup/disc area ratio, cup depth and peripapillary RNFL thickness were evaluated using HRT II, a confoal scanning ophtalmoscopy. Results: In the study group, there were 26 (65% men and 14 (35% women, whereas there were 27 (64% men and 15 (36% women in the control group (Chi square test, p=0.89. Mean age of the patients in the study and control groups was 59.4±10.3 and 57.7±9.1 years, respectively (T test, p=0.72. There was not any statistically significant difference regarding mean spheric equivalent between the two groups (Mann-Whitney U-test, p=0.203. The NAION unaffected fellow eyes had significantly smaller disc areas, cup areas, cup volumes, cup-disc area ratios (vertical and lineer, and cup depths than the control eyes (Mann-Whitney U-test; p<0.05, whereas there was no significant difference in the RNFL thickness between the two. Conclusion: A comparison of the fellow eyes in patients with unilateral NAION and the control eyes showed a significant difference in optic disc parameters and the morphology of RNFL. These differences could be important in the pathogenesis of NAION and needs to have further investigated. (Turk J Ophthalmol 2015; 45: 111-114

  12. Macular ganglion cell complex and retinal nerve fiber layer comparison in different stages of age-related macular degeneration.

    Science.gov (United States)

    Zucchiatti, Ilaria; Parodi, Maurizio Battaglia; Pierro, Luisa; Cicinelli, Maria Vittoria; Gagliardi, Marco; Castellino, Niccolò; Bandello, Francesco

    2015-09-01

    To employ optical coherence tomography (OCT) to analyze the morphologic changes in the inner retina in different categories of age-related macular degeneration (AMD). Observational cross-sectional study. Single-center study. Inclusion criteria were age over 50, diagnosis of Age-Related Eye Disease Study (AREDS) category 2 and 3, naïve neovascular AMD, and atrophic AMD. Healthy patients of similar age acted as a control group. Primary outcome measures were the changes in ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). Secondary outcomes included modifications of rim area and cup-to-disc ratio. One hundred and thirty eyes of 130 patients were recruited: 26 eyes for AREDS category 2, 26 for AREDS category 3, 26 for neovascular AMD, 26 with atrophic AMD, and 26 controls. Mean peripapillary RNFL thickness was significantly lower in neovascular AMD, compared to controls (P = .004); peripapillary RNFL did not significantly vary among AREDS category 2 and 3 and atrophic AMD groups, compared to controls. Mean GCC thickness was higher in the control group, becoming progressively thinner up to neovascular and atrophic AMD groups (P < .0001). Rim area was significantly thinner in the neovascular AMD group compared with controls (P = .047); cup-to-disc ratio was higher in the neovascular AMD group compared with the control group (P = .047). This study demonstrates that eyes with neovascular AMD display reduced RNFL and GCC thickness. RNFL is partially spared in atrophic advanced AMD. The identification of alteration in RNFL and GCC thickness may reveal useful for future therapeutic implications. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Abnormal retinal nerve fiber layer thickness and macula lutea in patients with mild cognitive impairment and Alzheimer's disease.

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    Gao, LiYan; Liu, Ying; Li, XiaoHong; Bai, QuanHao; Liu, Ping

    2015-01-01

    We investigated possible abnormalities in the retinal nerve fiber layer (RNFL) and macula lutea of patients diagnosed with Alzheimer's disease (AD) and mild cognitive impairment (MCI) and tested for any correlation with the severity of dementia. A total of 72 subjects, comprising 25 AD patients, 26 MCI patients and 21 healthy individuals (controls) were enrolled in this study. The thickness of the RNFL and volume of the macula lutea was determined using optical coherence tomography (OCT). When compared with controls, we found statistically significant thinning of the RNFL in AD patients at all clock-hour positions except 12:00, and nasal quadrant, 2:00, 3:00 and 4:00. After adjusting several risk factors, the average thickness of the RNFL was reduced in MCI patients compared to AD patients, with specific reductions at inferior quadrant, 5:00 and 6:00. Compared to controls, MCI patients showed a significant decrease in RNFL thickness only in the temporal quadrant, 8:00, 9:00 and 10:00. We found significant reduction in the volume of the macula lutea both in AD and MCI patients. Finally, we could not establish any correlation between patient Mini-Mental State Examination (MMSE) scores (an estimation of the severity of cognitive impairment) and any OCT parameter. Retinal degeneration in AD and MCI patients results in decreased thickness of the RNFL, and reduced macular volume in AD and MCI patients. However, there seems to be no correlation between these changes and the severity of dementia. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Peripapillary Retinal Nerve Fiber Measurement with Spectral-Domain Optical Coherence Tomography in Age-Related Macular Degeneration

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    Simon K. Law

    2017-12-01

    Full Text Available Purpose: To evaluate the relationship between the peripapillary retinal nerve fiber layer (RNFL measurements with Spectral-domain Optical Coherence Tomography (OCT and Age-related macular degeneration (AMD. Methods: Patients >60 years of age without glaucoma or record of intraocular pressure >21 mmHg and no systemic or intraocular diseases or treatment or surgical intervention that affected the RNFL underwent OCT measurement of the RNFL. The severity of AMD was staged with the Clinical Age-Related Maculopathy Staging System. The relationship between RNFL measurements and AMD stages of one eye per patient was analyzed. Results: Eighty-six eyes (46 patients with AMD and no glaucoma or other exclusion criteria received OCT RNFL measurements. Nine eyes (10.5% were excluded because of distorted peripapillary anatomy from exudative AMD (7 eyes or failure of the RNFL segmentation algorithm (2 eyes. Mean age ± S.D. of the 43 patients analyzed was 81.2 ± 7.3 years. The mean stage ± S.D. of AMD of the 77 eyes was 3.77 ± 1.05. Higher stages of AMD were statistically significantly associated with lower average RNFL and inferior sector RNFL (p = 0.049, 0 0015, respectively. The association of inferior sector RNFL and AMD stage remained statistically significant after adjusting for age. Conclusions: Spectral domain OCT is generally useful in measuring the peripapillary RNFL in eyes with different stages of AMD. Higher stage of AMD is associated with thinner peripapillary RNFL, which may masquerade as early glaucomatous damage.

  15. Evaluation of retinal nerve fiber layer thickness in vernal keratoconjunctivitis patients under long-term topical corticosteroid therapy.

    Science.gov (United States)

    Cingu, Abdullah Kursat; Cinar, Yasin; Turkcu, Fatih Mehmet; Sahinoglu-Keskek, Nedime; Sahin, Alparslan; Sahin, Muhammed; Yuksel, Harun; Caca, Ihsan

    2014-09-01

    The aim of this study was to evaluate the retinal nerve fiber layer (RNFL) thickness in vernal keratoconjunctivitis (VKC) patients who were under long-term topical corticosteroid therapy. Thirty-six eyes of 36 VKC patients with clear cornea and normal videokeratography and 40 eyes of 40 age- and gender-matched normal children were included in the study. Clinical and demographic characteristics of the patients were noted and detailed ophthalmological examination was performed. Visual acuity (VA), spherical equivalent (SE), axial length (AL) and RNFL thickness measurements were compared between the groups. To correct ocular magnification effect on RNFL, we used Littmann's formula. All VKC patients had history of topical corticosteroid use and the mean duration of the topical corticosteroid use was 23.8 ± 9.09 months. There was no significant difference between the groups in terms of intraocular pressure (IOP). VKC group had significantly worse VA, greater SE and AL and thinner mean global, superior and inferior RNFL thickness. There were significant negative correlations between the duration of topical corticosteroid use and the mean global, superior and temporal RNFL thickness in VKC group. After correction of magnification effect, VKC group still had thinner mean global, superior and inferior RNFL thickness, and significant difference between the groups in inferior RNFL thickness did not disappear. Significant RNFL thickness difference between the groups suggests a possible effect of long-term corticosteroid use in VKC patients. Because visual field (VF) analysis in pediatric patients is difficult to perform and IOP may be illusive, RNFL thickness measurements in addition to routine examinations in VKC patients may help clinicians in their practice.

  16. A comparison of anesthetic agents and their effects on the response properties of the peripheral auditory system.

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    Dodd, F; Capranica, R R

    1992-10-01

    Anesthetic agents were compared in order to identify the most appropriate agent for use during surgery and electrophysiological recordings in the auditory system of the tokay gecko (Gekko gecko). Each agent was first screened for anesthetic and analgesic properties and, if found satisfactory, it was subsequently tested in electrophysiological recordings in the auditory nerve. The following anesthetic agents fulfilled our criteria and were selected for further screening: sodium pentobarbital (60 mg/kg); sodium pentobarbital (30 mg/kg) and oxymorphone (1 mg/kg); 3.2% isoflurane; ketamine (440 mg/kg) and oxymorphone (1 mg/kg). These agents were subsequently compared on the basis of their effect on standard response properties of auditory nerve fibers. Our results verified that different anesthetic agents can have significant effects on most of the parameters commonly used in describing the basic response properties of the auditory system in vertebrates. We therefore conclude from this study that the selection of an appropriate experimental protocol is critical and must take into consideration the effects of anesthesia on auditory responsiveness. In the tokay gecko, we recommend 3.2% isoflurane for general surgical procedures; and for electrophysiological recordings in the eighth nerve we recommend barbiturate anesthesia of appropriate dosage in combination if possible with an opioid agent to provide additional analgesic action.

  17. One-Step Synthesis of Hollow Titanate (Sr/Ba Ceramic Fibers for Detoxification of Nerve Agents

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    Satya R. Agarwal

    2012-01-01

    Full Text Available Poly(vinyl pyrrolidone(PVP/(strontium/barium acetate/titanium isopropoxide composite fibers were prepared by electrospinning technique via sol-gel process. Diameters of fibers prepared by calcinations of PVP composite fibers were 80–140 nm (solid and 1.2-2.2 μm (hollow fibers prepared by core-shell method. These fibers were characterized using scanning electron microscope (SEM, X-ray diffraction (XRD, and transmission electron microscope (TEM analytical techniques. XRD results showed better crystalline nature of the materials when calcined at higher temperatures. SEM and TEM results clearly showed the formation of hollow submicrometer tubes. The surface area of the samples determined by BET analysis indicated that hollow fibers have ~20% higher surface area than solid fibers. The UV studies indicate better detoxification properties of the hollow fibers compared to solid fibers.

  18. EFFECT OF INTRAVITREAL RANIBIZUMAB ON GANGLION CELL COMPLEX AND PERIPAPILLARY RETINAL NERVE FIBER LAYER IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

    Science.gov (United States)

    Zucchiatti, Ilaria; Cicinelli, Maria V; Parodi, Maurizio Battaglia; Pierro, Luisa; Gagliardi, Marco; Accardo, Agostino; Bandello, Francesco

    2017-07-01

    To analyze the changes in ganglion cell complex and peripapillary retinal nerve fiber layer thickness, in central macular thickness and choroidal thickness on spectral domain optical coherence tomography in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. All consecutive patients with untreated neovascular age-related macular degeneration received loading phase of three monthly intravitreal ranibizumab, followed by retreatments on a pro re nata protocol for 12 months. changes in ganglion cell complex and retinal nerve fiber layer at the end of follow-up. Secondary outcome: changes in best-corrected visual acuity, central macular thickness, and choroidal thickness at the end of follow-up. Choroidal thickness was measured at 500 μm, 1000 μm, and 1,500 μm intervals nasally, temporally, superiorly, and inferiorly to the fovea, respectively, on horizontal and vertical line scans centered on the fovea. Twenty-four eyes were included. Ganglion cell complex and peripapillary retinal nerve fiber layer thickness did not show statistically significant changes through 12 months (55.6 ± 18.5 and 81.9 ± 9.9 μm at baseline, 52.7 ± 19.3 and 84.6 ± 15.5 μm at month 12, P > 0.05). Central macular thickness showed progressive decrease from baseline to month 12, with maximum reduction at month 3 (P macular thickness was significantly reduced at the end of treatment. Further studies, with larger sample, longer follow-up, and greater number of injections, are warranted.

  19. Análise quantitativa das fibras mielínicas dos nervos laríngeos em humanos de acordo com a idade Quantitative analysis of myelinic fibers in human laryngeal nerves according to age

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    Romualdo Suzano Louzeiro Tiago

    2008-02-01

    Full Text Available INTRODUÇÃO E OBJETIVO: Realizar análise morfométrica das fibras mielínicas dos nervos laríngeos com a finalidade de verificar modificações quantitativas decorrentes do processo de envelhecimento. FORMA DE ESTUDO: Clínico e experimental. Material e Método: Foi coletado fragmento de 1cm dos nervos laríngeos superiores e nervos laríngeos recorrentes de 12 cadáveres do sexo masculino. A amostra foi dividida em dois grupos: idade inferior a 60 anos (Adulto e idade igual ou superior a 60 anos (Idoso. O material foi avaliado em microscópio de luz acoplado a sistema analisador de imagem. RESULTADOS: O número total de fibras mielínicas do nervo laríngeo superior foi semelhante nos dois grupos etários, mas com tendência para o maior número de fibras de 1µm no grupo adulto (p=0,0744. O grupo adulto apresentou maior número total de fibras mielínicas no nervo laríngeo recorrente (p=0,0006, e esta diferença ocorreu nas fibras com diâmetros de 1-3µm (pINTRODUCTION AND AIM: To carry out a morphometric analysis of myelinic fibers in laryngeal nerves aiming to identify quantitative changes as a result of aging. Study design: Clinical and experimental. MATERIAL AND METHOD: A 1cm fragment was collected from the superior laryngeal nerves and recurrent laryngeal nerves taken from twelve male cadavers. The sample was divided into two groups: those aged below 60 years (Adult and those aged 60 years or more (Elderly. The material was evaluated under light microscopy coupled with an image analysis system. RESULTS: The total number of myelinic fibers from the superior laryngeal nerve was similar in both age groups; there was, however, a trend for a higher number of 1μm fibers in the adult group (p=0.0744. The adult group had a higher total number of myelinic fibers in the recurrent laryngeal nerve (p=0.0006, and this difference was seen in fibers with diameters betwee 1-3μm (p<0.007. The adult group had a higher total number of myelinic fibers

  20. Sodium Channel Nav1.8 Underlies TTX-Resistant Axonal Action Potential Conduction in Somatosensory C-Fibers of Distal Cutaneous Nerves.

    Science.gov (United States)

    Klein, Amanda H; Vyshnevska, Alina; Hartke, Timothy V; De Col, Roberto; Mankowski, Joseph L; Turnquist, Brian; Bosmans, Frank; Reeh, Peter W; Schmelz, Martin; Carr, Richard W; Ringkamp, Matthias

    2017-05-17

    Voltage-gated sodium (Na V ) channels are responsible for the initiation and conduction of action potentials within primary afferents. The nine Na V channel isoforms recognized in mammals are often functionally divided into tetrodotoxin (TTX)-sensitive (TTX-s) channels (Na V 1.1-Na V 1.4, Na V 1.6-Na V 1.7) that are blocked by nanomolar concentrations and TTX-resistant (TTX-r) channels (Na V 1.8 and Na V 1.9) inhibited by millimolar concentrations, with Na V 1.5 having an intermediate toxin sensitivity. For small-diameter primary afferent neurons, it is unclear to what extent different Na V channel isoforms are distributed along the peripheral and central branches of their bifurcated axons. To determine the relative contribution of TTX-s and TTX-r channels to action potential conduction in different axonal compartments, we investigated the effects of TTX on C-fiber-mediated compound action potentials (C-CAPs) of proximal and distal peripheral nerve segments and dorsal roots from mice and pigtail monkeys ( Macaca nemestrina ). In the dorsal roots and proximal peripheral nerves of mice and nonhuman primates, TTX reduced the C-CAP amplitude to 16% of the baseline. In contrast, >30% of the C-CAP was resistant to TTX in distal peripheral branches of monkeys and WT and Na V 1.9 -/- mice. In nerves from Na V 1.8 -/- mice, TTX-r C-CAPs could not be detected. These data indicate that Na V 1.8 is the primary isoform underlying TTX-r conduction in distal axons of somatosensory C-fibers. Furthermore, there is a differential spatial distribution of Na V 1.8 within C-fiber axons, being functionally more prominent in the most distal axons and terminal regions. The enrichment of Na V 1.8 in distal axons may provide a useful target in the treatment of pain of peripheral origin. SIGNIFICANCE STATEMENT It is unclear whether individual sodium channel isoforms exert differential roles in action potential conduction along the axonal membrane of nociceptive, unmyelinated peripheral nerve

  1. Alterations in retinal nerve fiber layer thickness in early stages of diabetic retinopathy and potential risk factors.

    Science.gov (United States)

    Shi, Rui; Guo, Zhonglan; Wang, Feng; Li, Rong; Zhao, Lei; Lin, Rong

    2018-02-01

    To investigate the loss of retinal nerve fiber layer (RNFL) in type-2 diabetic patients with early-stage diabetic retinopathy (DR) and to identify potential risk factors accounting for these alterations. In this cross-sectional study, 158 type-2 diabetic patients were divided into three groups based on their DR status. RNFL thickness and other optic disc parameters were obtained by optical coherence tomography (OCT) and then compared among different groups. We investigated the potential association between RNFL loss and systemic risk factors for DR, including diabetes duration, body mass index (BMI), serum lipids, hemoglobin A1c (HbA1c) and albumin-creatinine ratio (ACR). One-way ANOVA was carried out to compare RNFL thickness among different groups, Pearson correlation and multivariate linear regression analysis were performed to determine potential risk factors related to RNFL thickness in these patients. There were significant differences in the average (F = 8.872, P = 0.003), superior (F = 8.769, P = 0.004), and inferior (F = 8.857, P = 0.003) RNFL thickness of both eyes among the groups, but no obvious difference in optic disc parameters was found. Diabetic duration, BMI, TG, High density lipoprotein cholesterol (HDL), HbA1c, and ACR were found negatively related to the RNFL thickness in both or single eye according to Pearson correlation analysis. After controlling for age, gender, and axis length (AL) in multivariate linear regression analysis, the diabetic duration was associated significantly with RNFL thickness of superior in both eye (right eye: p = 0.016, left eye: p = 0.024), BMI was related to the nasal quadrant of the right eye (p = 0.034), and TG was related to the inferior of the right eye (p = 0.037), HbA1c (p = 0.026) was associated significantly with the average RNFL thickness of the right eye. In addition, ACR was found negatively related to average (p = 0.042) and inferior quadrant (p = 0.014) of the left eye

  2. Systemic and Ocular Determinants of Peripapillary Retinal Nerve Fiber Layer Thickness Measurements in the European Eye Epidemiology (E3) Population.

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    Mauschitz, Matthias M; Bonnemaijer, Pieter W M; Diers, Kersten; Rauscher, Franziska G; Elze, Tobias; Engel, Christoph; Loeffler, Markus; Colijn, Johanna Maria; Ikram, M Arfan; Vingerling, Johannes R; Williams, Katie M; Hammond, Christopher J; Creuzot-Garcher, Catherine; Bron, Alain M; Silva, Rufino; Nunes, Sandrina; Delcourt, Cécile; Cougnard-Grégoire, Audrey; Holz, Frank G; Klaver, Caroline C W; Breteler, Monique M B; Finger, Robert P

    2018-04-28

    To investigate systemic and ocular determinants of peripapillary retinal nerve fiber layer thickness (pRNFLT) in the European population. Cross-sectional meta-analysis. A total of 16 084 European adults from 8 cohort studies (mean age range, 56.9±12.3-82.1±4.2 years) of the European Eye Epidemiology (E3) consortium. We examined associations with pRNFLT measured by spectral-domain OCT in each study using multivariable linear regression and pooled results using random effects meta-analysis. Determinants of pRNFLT. Mean pRNFLT ranged from 86.8±21.4 μm in the Rotterdam Study I to 104.7±12.5 μm in the Rotterdam Study III. We found the following factors to be associated with reduced pRNFLT: Older age (β = -0.38 μm/year; 95% confidence interval [CI], -0.57 to -0.18), higher intraocular pressure (IOP) (β = -0.36 μm/mmHg; 95% CI, -0.56 to -0.15), visual impairment (β = -5.50 μm; 95% CI, -9.37 to -1.64), and history of systemic hypertension (β = -0.54 μm; 95% CI, -1.01 to -0.07) and stroke (β = -1.94 μm; 95% CI, -3.17 to -0.72). A suggestive, albeit nonsignificant, association was observed for dementia (β = -3.11 μm; 95% CI, -6.22 to 0.01). Higher pRNFLT was associated with more hyperopic spherical equivalent (β = 1.39 μm/diopter; 95% CI, 1.19-1.59) and smoking (β = 1.53 μm; 95% CI, 1.00-2.06 for current smokers compared with never-smokers). In addition to previously described determinants such as age and refraction, we found that systemic vascular and neurovascular diseases were associated with reduced pRNFLT. These may be of clinical relevance, especially in glaucoma monitoring of patients with newly occurring vascular comorbidities. Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  3. Effects of multiple intravitreal anti-VEGF injections on retinal nerve fiber layer and intraocular pressure: a comparative clinical study.

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    Sobacı, Güngör; Güngör, Rıza; Ozge, Gökhan

    2013-01-01

    To determine the effect of multiple injections of ranibizumab or bevacizumab on retinal nerve fiber layer (RNFL) and intraocular pressure (IOP) in patients with age-related macular degeneration (AMD). This retrospective study includes 35 eyes of 35 patients treated with intravitreal bevacizumab (IVB, 1.25mg/0.05mL) and 30 eyes of 30 patients with intravitreal ranibizumab (IVR, 0.5mg/0.05mL) who had Fast RNFL analysis (Stratus™); IOP measurements were taken 30 minutes and 24 hours after each injection. The mean ages were 68.0±7.5 and 69.1±7.7 years in the IVR and IVB groups, respectively (P=0.55). They underwent (6.3±1.9) and (5.1±1.3) injections (P=0.07) over (13.6±2.1) and (14.05±2.6) months (P=0.45) in the IVR and IVB groups, respectively. Changes in overall and temporal RNFL thickness in IVR-treated eyes (105.3±6.9µm and 74.4±11.2µm) were not different from those in untreated eyes in the IVR group (104.6± 8.4µm and 75.1±12.6µm) (P=0.57 and P=0.41, respectively). Similarly, overall and temporal RNFL thickness in IVB-treated eyes (105.8±8.1µm and 74.5±11.8µm) were not different from those in untreated eyes in the IVB group (104.6±8µm and 74.8±12.9µm) (P=0.42 and P=0.80, respectively). The frequencies of IOP rise (P=0.60) and changes in RNFL thickness from baseline (P=0.16) were comparable between groups. Repeated intravitreal injection of ranibizumab or bevacizumab does not seem have adverse effects on RNFL thickness or IOP in wet AMD patients.

  4. Retina ganglion cell/inner plexiform layer and peripapillary nerve fiber layer thickness in patients with acromegaly.

    Science.gov (United States)

    Şahin, Muhammed; Şahin, Alparslan; Kılınç, Faruk; Yüksel, Harun; Özkurt, Zeynep Gürsel; Türkcü, Fatih Mehmet; Pekkolay, Zafer; Soylu, Hikmet; Çaça, İhsan

    2017-06-01

    Increased secretion of growth hormone and insulin-like growth factor-1 in acromegaly has various effects on multiple organs. However, the ocular effects of acromegaly have yet to be investigated in detail. The aim of the present study was to compare retina ganglion cell/inner plexiform layer (GCIPL) and peripapillary nerve fiber layer thickness (pRNFL) between patients with acromegaly and healthy control subjects using spectral domain optical coherence tomography (SD-OCT). This cross-sectional, comparative study included 18 patients with acromegaly and 20 control subjects. All participants underwent SD-OCT to measure pRNFL (in the seven peripapillary areas), GCIPL (in the nine ETDRS areas), and central macular thickness (CMT). Visual field (VF) examinations were performed using a Humphrey field analyzer in acromegalic patients. Measurements were compared between patients with acromegaly and control subjects. A total of 33 eyes of 18 patients with acromegaly and 40 eyes of 20 control subjects met the inclusion criteria of the present study. The overall calculated average pRNFL thickness was significantly lower in patients with acromegaly than in control subjects (P = 0.01), with pRNFL thickness significantly lower in the temporal superior and temporal inferior quadrants. Contrary to our expectations, pRNFL thickness in the nasal quadrant was similar between acromegalic and control subjects. The mean overall pRNFL thickness and superonasal, nasal, inferonasal, and inferotemporal quadrant pRNFL thicknesses were found to correlate with the mean deviation (MD) according to Spearman's correlation. However, other quadrants were not correlated with VF sensitivity. No significant difference in CMT values was observed (P = 0.6). GCIPL thickness was significantly lower in all quadrants of the inner and outer macula, except for central and inferior outer quadrants, in the acromegaly group than that in the control group (P acromegaly compared with that in control subjects

  5. A Rare Case Report and Literature Review of External Auditory Canal Cholesteatoma with Circumferential Destruction of Canal Wall Exposing Facial Nerve

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    Leison Maharjan

    2017-01-01

    Full Text Available External auditory canal cholesteatoma (EACC is a rare condition with an estimated incidence of 1.2 per 1000 new otological patients. It is often mistaken with keratosis obturans. We discuss an extensive primary EACC with an aural polyp in a male which was managed by modified radical mastoidectomy.

  6. Repeatability and Reproducibility of Retinal Nerve Fiber Layer Parameters Measured by Scanning Laser Polarimetry with Enhanced Corneal Compensation in Normal and Glaucomatous Eyes.

    Science.gov (United States)

    Ara, Mirian; Ferreras, Antonio; Pajarin, Ana B; Calvo, Pilar; Figus, Michele; Frezzotti, Paolo

    2015-01-01

    To assess the intrasession repeatability and intersession reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness parameters measured by scanning laser polarimetry (SLP) with enhanced corneal compensation (ECC) in healthy and glaucomatous eyes. One randomly selected eye of 82 healthy individuals and 60 glaucoma subjects was evaluated. Three scans were acquired during the first visit to evaluate intravisit repeatability. A different operator obtained two additional scans within 2 months after the first session to determine intervisit reproducibility. The intraclass correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRT) were calculated for all SLP parameters in both groups. ICCs ranged from 0.920 to 0.982 for intravisit measurements and from 0.910 to 0.978 for intervisit measurements. The temporal-superior-nasal-inferior-temporal (TSNIT) average was the highest (0.967 and 0.946) in normal eyes, while nerve fiber indicator (NFI; 0.982) and inferior average (0.978) yielded the best ICC in glaucomatous eyes for intravisit and intervisit measurements, respectively. All COVs were under 10% in both groups, except NFI. TSNIT average had the lowest COV (2.43%) in either type of measurement. Intervisit TRT ranged from 6.48 to 12.84. The reproducibility of peripapillary RNFL measurements obtained with SLP-ECC was excellent, indicating that SLP-ECC is sufficiently accurate for monitoring glaucoma progression.

  7. Retinal Nerve Fiber Layer and Peripapillary Choroidal Thicknesses in Non-Glaucomatous Unilateral Optic Atrophy Compared with Unilateral Advanced Pseudoexfoliative Glaucoma.

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    Kucukevcilioglu, Murat; Ayyildiz, Onder; Aykas, Seckin; Gokce, Gokcen; Koylu, Mehmet Talay; Ozgonul, Cem; Ozge, Gokhan; Mumcuoglu, Tarkan; Yumusak, Erhan

    2017-02-01

    To investigate retinal nerve fiber layer thickness (RNFL-T) and peripapillary choroidal thickness (PC-T) in non-glaucomatous optic atrophy (OA) patients in comparison with unaffected and control eyes, furthermore, to compare thickness profiles with unilateral pseudoexfoliative advanced glaucoma. Thirty-three eyes with OA (Group A), 33 unaffected fellow eyes (Group B), 25 right eyes of 25 control subjects (Group C), and 15 eyes with advanced glaucoma (Group D) were enrolled. RNFL-T was measured in six regions by spectral-domain optical coherence tomography. Enhanced depth imaging optical coherence tomography was obtained to evaluate PC-T in corresponding regions. RNFL-T was significantly lower in Group A than in Groups B and C globally and at all peripapillary regions (all p temporal > nasal > inferior) profiles were almost identical to that in unaffected fellow eyes and control eyes. However, Group D showed different patterns with less regional differences in RNFL-T, and the greatest value of PC-T in nasal quadrant. Besides retinal nerve fiber layer thinning, non-glaucomatous OA is associated with choroidal thinning. The RNFL-T and PC-T profiles in advanced glaucoma eyes differed from the common patterns seen among OA eyes, unaffected fellow eyes, and control eyes.

  8. Polycystic Ovary Syndrome: Aggressive or Protective Factor for the Retina? Evaluation of Macular Thickness and Retinal Nerve Fiber Layers Using High-Definition Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    José Edvan de Souza-Júnior

    2015-01-01

    Full Text Available Objective. To compare macular thickness (MT and retinal nerve fiber layers (RNFL between women with polycystic ovary syndrome (PCOS and healthy women. Materials and Methods. The study included 45 women with PCOS and 47 ovulatory women undergoing clinical-gynecological and ophthalmic evaluations, including measurement of MT, RNFL, and optic disc parameters using optical coherence tomography. Results. The superior RNFL around the optic nerve was significantly thicker in PCOS than in healthy volunteers (P=0.036. After stratification according to insulin resistance, the temporal inner macula (TIM, the inferior inner macula (IIM, the nasal inner macula (NIM, and the nasal outer macula (NOM were significantly thicker in PCOS group than in control group (P<0.05. Both the presence of obesity associated with insulin resistance (P=0.037 and glucose intolerance (P=0.001 were associated with significant increase in the PC1 mean score, relative to MT. A significant increase in the PC2 mean score occurred when considering the presence of metabolic syndrome (P<0.0001. There was a significant interaction between obesity and inflammation in a decreasing mean PC2 score relative to macular RNFL thickness (P=0.034. Conclusion. Decreased macular RNFL thickness and increased total MT are associated with metabolic abnormalities, while increased RNFL thickness around the optic nerve is associated with hormonal changes inherent in PCOS.

  9. Large A-fiber activity is required for microglial proliferation and p38 MAPK activation in the spinal cord: different effects of resiniferatoxin and bupivacaine on spinal microglial changes after spared nerve injury

    Directory of Open Access Journals (Sweden)

    Decosterd Isabelle

    2009-09-01

    Full Text Available Abstract Background After peripheral nerve injury, spontaneous ectopic activity arising from the peripheral axons plays an important role in inducing central sensitization and neuropathic pain. Recent evidence indicates that activation of spinal cord microglia also contributes to the development of neuropathic pain. In particular, activation of p38 mitogen-activated protein kinase (MAPK in spinal microglia is required for the development of mechanical allodynia. However, activity-dependent activation of microglia after nerve injury has not been fully addressed. To determine whether spontaneous activity from C- or A-fibers is required for microglial activation, we used resiniferatoxin (RTX to block the conduction of transient receptor potential vanilloid subtype 1 (TRPV1 positive fibers (mostly C- and Aδ-fibers and bupivacaine microspheres to block all fibers of the sciatic nerve in rats before spared nerve injury (SNI, and observed spinal microglial changes 2 days later. Results SNI induced robust mechanical allodynia and p38 activation in spinal microglia. SNI also induced marked cell proliferation in the spinal cord, and all the proliferating cells (BrdU+ were microglia (Iba1+. Bupivacaine induced a complete sensory and motor blockade and also significantly inhibited p38 activation and microglial proliferation in the spinal cord. In contrast, and although it produced an efficient nociceptive block, RTX failed to inhibit p38 activation and microglial proliferation in the spinal cord. Conclusion (1 Blocking peripheral input in TRPV1-positive fibers (presumably C-fibers is not enough to prevent nerve injury-induced spinal microglial activation. (2 Peripheral input from large myelinated fibers is important for microglial activation. (3 Microglial activation is associated with mechanical allodynia.

  10. Surface microstructures on planar substrates and textile fibers guide neurite outgrowth: a scaffold solution to push limits of critical nerve defect regeneration?

    Directory of Open Access Journals (Sweden)

    Stefan Weigel

    Full Text Available The treatment of critical size peripheral nerve defects represents one of the most serious problems in neurosurgery. If the gap size exceeds a certain limit, healing can't be achieved. Connection mismatching may further reduce the clinical success. The present study investigates how far specific surface structures support neurite outgrowth and by that may represent one possibility to push distance limits that can be bridged. For this purpose, growth cone displacement of fluorescent embryonic chicken spinal cord neurons was monitored using time-lapse video. In a first series of experiments, parallel patterns of polyimide ridges of different geometry were created on planar silicon oxide surfaces. These channel-like structures were evaluated with and without amorphous hydrogenated carbon (a-C:H coating. In a next step, structured and unstructured textile fibers were investigated. All planar surface materials (polyimide, silicon oxide and a-C:H proved to be biocompatible, i.e. had no adverse effect on nerve cultures and supported neurite outgrowth. Mean growth cone migration velocity measured on 5 minute base was marginally affected by surface structuring. However, surface structure variability, i.e. ridge height, width and inter-ridge spacing, significantly enhanced the resulting net velocity by guiding the growth cone movement. Ridge height and inter-ridge distance affected the frequency of neurites crossing over ridges. Of the evaluated dimensions ridge height, width, and inter-ridge distance of respectively 3, 10, and 10 µm maximally supported net axon growth. Comparable artificial grooves, fabricated onto the surface of PET fibers by using an excimer laser, showed similar positive effects. Our data may help to further optimize surface characteristics of artificial nerve conduits and bioelectronic interfaces.

  11. Comparison of peripapillary retinal nerve fiber layer loss and visual outcome in fellow eyes following sequential bilateral non-arteritic anterior ischemic optic neuropathy.

    Science.gov (United States)

    Dotan, Gad; Kesler, Anat; Naftaliev, Elvira; Skarf, Barry

    2015-05-01

    To report on the correlation of structural damage to the axons of the optic nerve and visual outcome following bilateral non-arteritic anterior ischemic optic neuropathy. A retrospective review of the medical records of 25 patients with bilateral sequential non-arteritic anterior ischemic optic neuropathy was performed. Outcome measures were peripapillary retinal nerve fiber layer thickness measured with the Stratus optical coherence tomography scanner, visual acuity and visual field loss. Median peripapillary retinal nerve fiber layer (RNFL) thickness, mean deviation (MD) of visual field, and visual acuity of initially involved NAION eyes (54.00 µm, -17.77 decibels (dB), 0.4, respectively) were comparable to the same parameters measured following development of second NAION event in the other eye (53.70 µm, p = 0.740; -16.83 dB, p = 0.692; 0.4, p = 0.942, respectively). In patients with bilateral NAION, there was a significant correlation of peripapillary RNFL thickness (r = 0.583, p = 0.002) and MD of the visual field (r = 0.457, p = 0.042) for the pairs of affected eyes, whereas a poor correlation was found in visual acuity of these eyes (r = 0.279, p = 0.176). Peripapillary RNFL thickness following NAION was positively correlated with MD of visual field (r = 0.312, p = 0.043) and negatively correlated with logMAR visual acuity (r = -0.365, p = 0.009). In patients who experience bilateral NAION, the magnitude of RNFL loss is similar in each eye. There is a greater similarity in visual field loss than in visual acuity between the two affected eyes with NAION of the same individual.

  12. Pathology of the vestibulocochlear nerve

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    De Foer, Bert [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: bert.defoer@GZA.be; Kenis, Christoph [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: christophkenis@hotmail.com; Van Melkebeke, Deborah [Department of Neurology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Deborah.vanmelkebeke@Ugent.be; Vercruysse, Jean-Philippe [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: jphver@yahoo.com; Somers, Thomas [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Thomas.somers@GZA.be; Pouillon, Marc [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: marc.pouillon@GZA.be; Offeciers, Erwin [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Erwin.offeciers@GZA.be; Casselman, Jan W. [Department of Radiology, AZ Sint-Jan AV Hospital, Ruddershove 10, Bruges (Belgium); Consultant Radiologist, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium); Academic Consultent, University of Ghent (Belgium)], E-mail: jan.casselman@azbrugge.be

    2010-05-15

    There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

  13. Pathology of the vestibulocochlear nerve

    International Nuclear Information System (INIS)

    De Foer, Bert; Kenis, Christoph; Van Melkebeke, Deborah; Vercruysse, Jean-Philippe; Somers, Thomas; Pouillon, Marc; Offeciers, Erwin; Casselman, Jan W.

    2010-01-01

    There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

  14. Chitin biological absorbable catheters bridging sural nerve grafts transplanted into sciatic nerve defects promote nerve regeneration.

    Science.gov (United States)

    Wang, Zhi-Yong; Wang, Jian-Wei; Qin, Li-Hua; Zhang, Wei-Guang; Zhang, Pei-Xun; Jiang, Bao-Guo

    2018-06-01

    To investigate the efficacy of chitin biological absorbable catheters in a rat model of autologous nerve transplantation. A segment of sciatic nerve was removed to produce a sciatic nerve defect, and the sural nerve was cut from the ipsilateral leg and used as a graft to bridge the defect, with or without use of a chitin biological absorbable catheter surrounding the graft. The number and morphology of regenerating myelinated fibers, nerve conduction velocity, nerve function index, triceps surae muscle morphology, and sensory function were evaluated at 9 and 12 months after surgery. All of the above parameters were improved in rats in which the nerve graft was bridged with chitin biological absorbable catheters compared with rats without catheters. The results of this study indicate that use of chitin biological absorbable catheters to surround sural nerve grafts bridging sciatic nerve defects promotes recovery of structural, motor, and sensory function and improves muscle fiber morphology. © 2018 John Wiley & Sons Ltd.

  15. LONGITUDINAL CHANGES IN THICKNESSES OF THE MACULA, GANGLION CELL-INNER PLEXIFORM LAYER, AND RETINAL NERVE FIBER LAYER AFTER VITRECTOMY: A 12-Month Observational Study.

    Science.gov (United States)

    Lim, Hyung-Bin; Lee, Min-Woo; Kwak, Baek-Soo; Jo, Young-Joon; Kim, Jung-Yeul

    2018-01-01

    To analyze longitudinal changes in the thicknesses of the macula, ganglion cell-inner plexiform layer (GC-IPL), and peripapillary retinal nerve fiber layer (RNFL) after vitrectomy. Thirty-eight patients diagnosed with intraocular lens (IOL) dislocation without evidence of other vitreoretinal diseases were included. They underwent conventional vitrectomy and IOL transscleral fixation, with a follow-up of 12 months. Using spectral domain optical coherence tomography, the thicknesses of the macula, GC-IPL, and peripapillary RNFL in the vitrectomized and fellow control eyes were measured. Various optic nerve head parameters were also determined. Optical coherence tomography showed that there were no significant differences in postoperative central macular thickness compared with baseline values. The average GC-IPL thickness increased 1 month after surgery from baseline (P = 0.038). The average RNFL thickness increased from baseline at 1 month (P = 0.001) and 3 months (P = 0.011) after vitrectomy. The mean foveal, GC-IPL, and RNFL thicknesses of the study eyes compared with the fellow control eyes increased at 1 month (P = 0.034), 1 month (P = 0.048), and 1 month (P = 0.013) to 3 months (P = 0.038), respectively, after surgery. However, no significant differences were found in intraocular pressure or optic nerve head parameters between the study and fellow control eyes at 12 months after surgery. Transient increases in the thickness of the macula and GC-IPL were observed at 1 month after vitrectomy, and the postoperative RNFL thickness increased until 3 months after surgery, after which it returned to preoperative levels. There was no significant change in intraocular pressure or optic nerve head parameters before and after surgery.

  16. Size of the Optic Nerve Head and Its Relationship with the Thickness of the Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer in Patients with Primary Open Angle Glaucoma

    Directory of Open Access Journals (Sweden)

    Nobuko Enomoto

    2015-01-01

    Full Text Available Purpose. To evaluate the relationships among the optic nerve head (ONH area, macular ganglion cell complex (mGCC thickness, circumpapillary retinal nerve fiber layer (cpRNFL thickness, and visual field defects in patients with primary open angle glaucoma (POAG. Methods. This retrospective study included 90 eyes of 90 patients with POAG. The ONH area, rim area, mGCC thickness, and cpRNFL thickness were measured using optical coherence tomography. Mean deviation (MD was measured using standard automated perimetry. The relationships among clinical factors including age, refraction, the ONH area, the rim area, the mGCC thickness, the cpRNFL thickness, and MD were evaluated using correlation coefficients and multiple regression analyses. Results. The significant correlation of the ONH area with refraction (r=0.362, P<0.001, the mGCC thickness (r=0.225, P=0.033, and the cpRNFL thickness (r=0.253, P=0.016 was found. Multiple regression analysis showed that the ONH area, rim area, and MD were selected as significant contributing factors to explain the mGCC thickness and cpRNFL thickness. No factor was selected to explain MD. Conclusions. The ONH area, in other words, the disc size itself may affect the mGCC thickness and cpRNFL thickness in POAG patients.

  17. Afferent fibers and sensory ganglion cells within the oculomotor nerve in some mammals and man. II. Electrophysiological investigations.

    Science.gov (United States)

    Manni, E; Bortolami, R; Pettorossi, V E; Lucchi, M L; Callegari, E

    1978-01-01

    The main aim of the present study was to localize with electrophysiological techniques the central projections and terminations of the aberrant trigeminal fibres contained in the oculomotor nerve of the lamb. After severing a trigeminal root, single-shock electrical stimulation of the trigeminal axons present in the central stump of the ipsilateral oculomotor nerve evoked field potentials in the area of, i) the subnucleus gelatinosus of the nucleus caudalis trigemini at the level of C1-C2; ii) the main sensory trigeminal nucleus; iii) the descending trigeminal nucleus and tract; iv) the adjacent reticular formation. Units whose discharge rate was influenced by such a stimulation were also found in the same territories. These regions actually exhibited degenerations after cutting an oculomotor nerve. We conclude, therefore, that the trigeminal fibres which leave the Vth nerve at the level of the cavernous sinus and enter the brain stem through the IIIrd nerve, end in the same structures which receive the terminations of the afferent fibres entering the brain stem through the sensory trigeminal root.

  18. Bilateral duplication of the internal auditory canal

    International Nuclear Information System (INIS)

    Weon, Young Cheol; Kim, Jae Hyoung; Choi, Sung Kyu; Koo, Ja-Won

    2007-01-01

    Duplication of the internal auditory canal is an extremely rare temporal bone anomaly that is believed to result from aplasia or hypoplasia of the vestibulocochlear nerve. We report bilateral duplication of the internal auditory canal in a 28-month-old boy with developmental delay and sensorineural hearing loss. (orig.)

  19. Nerve Blocks

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Nerve Blocks A nerve block is an injection to ... the limitations of Nerve Block? What is a Nerve Block? A nerve block is an anesthetic and/ ...

  20. Asymptomatic loss of intraepidermal nerve fibers with preserved thermal detection thresholds after repeated exposure to severe cold

    DEFF Research Database (Denmark)

    Krøigård, Thomas; Wirenfeldt, Martin; Svendsen, Toke K.

    2018-01-01

    Background: Cold-induced peripheral neuropathy has been described in individuals exposed to severe cold resulting in pain, hypersensitivity to cold, hyperhidrosis, numbness, and skin changes. Nerve conduction studies and thermal detection thresholds are abnormal in symptomatic patients......-induced peripheral neuropathy may be prevalent in subjects living in or near polar regions which could have implications for the recruitment of healthy subjects....

  1. A mathematical model for describing the retinal nerve fiber bundle trajectories in the human eye : Average course, variability, and influence of refraction, optic disc size and optic disc position

    NARCIS (Netherlands)

    Jansonius, Nomdo M.; Schiefer, Julia; Nevalainen, Jukka; Paetzold, Jens; Schiefer, Ulrich

    2012-01-01

    Previously we developed a mathematical model for describing the retinal nerve fiber bundle trajectories in the superior-temporal and inferior-temporal regions of the human retina, based on traced trajectories extracted from fundus photographs. Aims of the current study were to (i) validate the

  2. Comparison of Ganglion Cell and Retinal Nerve Fiber Layer Thickness in Pigment Dispersion Syndrome, Pigmentary Glaucoma, and Healthy Subjects with Spectral-domain OCT.

    Science.gov (United States)

    Arifoglu, Hasan Basri; Simavli, Huseyin; Midillioglu, Inci; Berk Ergun, Sule; Simsek, Saban

    2017-01-01

    To evaluate the ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) thickness in pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) with RTVue spectral domain optical coherence tomography (SD-OCT). A total of 102 subjects were enrolled: 29 with PDS, 18 with PG, and 55 normal subjects. Full ophthalmic examination including visual field analysis was performed. SD-OCT was used to analyze GCC superior, GCC inferior, and average RNFL thickness. To compare the discrimination capabilities, the areas under the receiver operating characteristic curves were assessed. Superior GCC, inferior GCC, and RNFL thickness values of patients with PG were statistically signicantly lower than those of patients with PDS (p  0.05). The SD-OCT-derived GCC and RNFL thickness parameters can be useful to discriminate PG from both PDS and normal subjects.

  3. Evaluation of retinal nerve fiber layer thickness measurements using optical coherence tomography in patients with tobacco-alcohol-induced toxic optic neuropathy

    Directory of Open Access Journals (Sweden)

    Moura Frederico

    2010-01-01

    Full Text Available Three patients with progressive visual loss, chronic alcoholism and tabagism were submitted to a complete neuro-ophthalmic examination and to retinal nerve fiber layer (RNFL measurements using optical coherence tomography (OCT scanning. Two patients showed marked RNFL loss in the temporal sector of the optic disc. However, a third patient presented RNFL measurements within or above normal limits, based on the Stratus-OCT normative database. Such findings may be due to possible RNFL edema similar to the one that may occur in the acute phase of toxic optic neuropathies. Stratus-OCT was able to detect RNFL loss in the papillomacular bundle of patients with tobacco-alcohol-induced toxic optic neuropathy. However, interpretation must be careful when OCT does not show abnormality in order to prevent diagnostic confusion, since overestimation of RNFL thickness measurements is possible in such cases.

  4. The number and distribution of AMPA receptor channels containing fast kinetic GluA3 and GluA4 subunits at auditory nerve synapses depend on the target cells.

    Science.gov (United States)

    Rubio, María E; Matsui, Ko; Fukazawa, Yugo; Kamasawa, Naomi; Harada, Harumi; Itakura, Makoto; Molnár, Elek; Abe, Manabu; Sakimura, Kenji; Shigemoto, Ryuichi

    2017-11-01

    The neurotransmitter receptor subtype, number, density, and distribution relative to the location of transmitter release sites are key determinants of signal transmission. AMPA-type ionotropic glutamate receptors (AMPARs) containing GluA3 and GluA4 subunits are prominently expressed in subsets of neurons capable of firing action potentials at high frequencies, such as auditory relay neurons. The auditory nerve (AN) forms glutamatergic synapses on two types of relay neurons, bushy cells (BCs) and fusiform cells (FCs) of the cochlear nucleus. AN-BC and AN-FC synapses have distinct kinetics; thus, we investigated whether the number, density, and localization of GluA3 and GluA4 subunits in these synapses are differentially organized using quantitative freeze-fracture replica immunogold labeling. We identify a positive correlation between the number of AMPARs and the size of AN-BC and AN-FC synapses. Both types of AN synapses have similar numbers of AMPARs; however, the AN-BC have a higher density of AMPARs than AN-FC synapses, because the AN-BC synapses are smaller. A higher number and density of GluA3 subunits are observed at AN-BC synapses, whereas a higher number and density of GluA4 subunits are observed at AN-FC synapses. The intrasynaptic distribution of immunogold labeling revealed that AMPAR subunits, particularly GluA3, are concentrated at the center of the AN-BC synapses. The central distribution of AMPARs is absent in GluA3-knockout mice, and gold particles are evenly distributed along the postsynaptic density. GluA4 gold labeling was homogenously distributed along both synapse types. Thus, GluA3 and GluA4 subunits are distributed at AN synapses in a target-cell-dependent manner.

  5. Comparison of the nerve fiber layer of type 2 diabetic patients without glaucoma with normal subjects of the same age and sex

    Directory of Open Access Journals (Sweden)

    Takis A

    2014-02-01

    Full Text Available Alexandros Takis,1 Dimitrios Alonistiotis,1 Dimitrios Panagiotidis,1 Nikolaos Ioannou,1 Dimitris Papaconstantinou,2 Panagiotis Theodossiadis1 1Ophthalmological University Clinic of Athens, Attikon Hospital, Athens, Greece; 2Ophthalmological University Clinic of Athens, Geniko Kratiko Hospital, Athens, Greece Background: The retinal nerve fiber layer (RNFL thickness in patients with diabetes mellitus type 2 was compared to normal subjects of similar age and sex, having first excluded any risk factors for glaucoma. The correlation between the RNFL thickness and the severity of diabetic retinopathy was investigated at its primary stages and with other ocular and diabetic parameters. Methods: A prospective, case series study was carried out. Twenty-seven diabetic patients without diabetic retinopathy, 24 diabetic patients with mild retinopathy, and 25 normal, age-matched subjects underwent a complete ophthalmological examination and imaging with scanning laser polarimetry for the evaluation of the RNFL. Multivariate analysis was applied in order to investigate the correlation between RNFL and diabetic parameters, such as age, duration of diabetes, insulin therapy, levels of glycosylated hemoglobin; and ocular parameters, such as cup to disc ratio, levels of normal intraocular pressure, and central corneal thickness. Results: The mean inferior average of RNFL and the temporal-superior-nasal-inferior-temporal standard deviation were statistically significantly lower in both diabetic groups, and the nerve fiber index was higher (P=0.04 compared to the normal group. There was no statistically significant difference between the diabetic groups. The factor analysis showed no significant correlation between the RNFL and the previously mentioned diabetic and ocular parameters. Conclusion: The existence of diabetes should be seriously considered in evaluating the results of scanning laser polarimetry. Multivariate analysis for RNFL was used for the first

  6. Analysis of macular and nerve fiber layer thickness in multiple sclerosis patients according to severity level and optic neuritis episodes.

    Science.gov (United States)

    Soler García, A; Padilla Parrado, F; Figueroa-Ortiz, L C; González Gómez, A; García-Ben, A; García-Ben, E; García-Campos, J M

    2016-01-01

    Quantitative assessment of macular and nerve fibre layer thickness in multiple sclerosis patients with regard to expanded disability status scale (EDSS) and presence or absence of previous optic neuritis episodes. We recruited 62 patients with multiple sclerosis (53 relapsing-remitting and 9 secondary progressive) and 12 disease-free controls. All patients underwent an ophthalmological examination, including quantitative analysis of the nerve fibre layer and macular thickness using optical coherence tomography. Patients were classified according to EDSS as A (lower than 1.5), B (between 1.5 and 3.5), and C (above 3.5). Mean nerve fibre layer thickness in control, A, B, and C groups was 103.35±12.62, 99.04±14.35, 93.59±15.41, and 87.36±18.75μm respectively, with statistically significant differences (P<.05). In patients with no history of optic neuritis, history of episodes in the last 3 to 6 months, or history longer than 6 months, mean nerve fibre layer thickness was 99.25±13.71, 93.92±13.30 and 80.07±15.91μm respectively; differences were significant (P<.05). Mean macular thickness in control, A, B, and C groups was 220.01±12.07, 217.78±20.02, 217.68±20.77, and 219.04±24.26μm respectively. Differences were not statistically significant. The mean retinal nerve fibre layer thickness in multiple sclerosis patients is related to the EDSS level. Patients with previous optic neuritis episodes have a thinner retinal nerve fibre layer than patients with no history of these episodes. Mean macular thickness is not correlated to EDSS level. Copyright © 2014 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Evaluation of Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer in Primary Craniopharyngioma by Fourier-Domain Optical Coherence Tomography.

    Science.gov (United States)

    Yang, Liu; Qu, Yuanzhen; Lu, Wen; Liu, Fengjun

    2016-07-03

    BACKGROUND The aim of this study was to compare the differences in macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) in child and adult patients with primary craniopharyngioma by Fourier-domain optical coherence tomography (FD-OCT) and to evaluate their significance in the diagnosis of primary craniopharyngioma. MATERIAL AND METHODS Ninety-six participants were divided into 3 groups: 32 in the child craniopharyngioma group (CCG) and 32 in the adult craniopharyngioma group (ACG) who were treated in Beijing Tiantan Hospital between November 2013 and October 2014, and 32 in the normal group (NG). All subjects were scanned by FD-OCT to map GCC and pRNFL thicknesses. Spearman correlation coefficient was used to assess the correlation between GCC and pRNFL thickness, and pRNFL thickness and optic nerve head (ONH) parameters, including horizontal cup-disc ratio (HCDR), vertical cup-disc ratio (VCDR), optic disc area (ODA), and cup area (CA), respectively. RESULTS The correlation between GCC and pRNFL thickness in the CCG was slightly stronger compared with the ACG. A significant difference in GCC thickness was observed among the CCG, ACG, and NG. Although the pRNFL thickness in both the CCG and ACG was significantly higher than that in NG, no significant difference in pRNFL thickness was detected between the 2 craniopharyngioma groups. The average, superior, and inferior pRNFL thicknesses were negatively correlated with VCDR in the CCG (in double eyes) and ACG (only in left eyes). CONCLUSIONS GCC was more sensitive than pRNFL in detecting optic nerve damage in the eyes of craniopharyngioma patients. A thinner pRNFL was especially correlated with VCDR in child craniopharyngioma patients.

  8. Peripapillary Retinal Nerve Fiber Layer Thickness Corresponds to Drusen Location and Extent of Visual Field Defects in Superficial and Buried Optic Disc Drusen.

    Science.gov (United States)

    Malmqvist, Lasse; Wegener, Marianne; Sander, Birgit A; Hamann, Steffen

    2016-03-01

    Optic disc drusen (ODD) are hyaline deposits located within the optic nerve head. Peripapillary retinal nerve fiber layer (RNFL) thinning is associated with the high prevalence of visual field defects seen in ODD patients. The goal of this study was to investigate the characteristics of patients with ODD and to compare the peripapillary RNFL thickness to the extent of visual field defects and anatomic location (superficial or buried) of ODD. Retrospective, cross sectional study. A total of 149 eyes of 84 ODD patients were evaluated. Sixty-five percent were female and 76% had bilateral ODD. Of 149 eyes, 109 had superficial ODD and 40 had buried ODD. Peripapillary RNFL thinning was seen in 83.6% of eyes, where optical coherence tomography was performed (n = 61). Eyes with superficial ODD had greater mean peripapillary RNFL thinning (P ≤ 0.0001) and visual field defects (P = 0.002) than eyes with buried ODD. There was a correlation between mean peripapillary RNFL thinning and visual field defects as measured by perimetric mean deviation (R-0.66; P = 0.0001). The most frequent visual field abnormalities were arcuate and partial arcuate defects. Peripapillary RNFL thickness correlates with anatomic location (superficial or buried) of ODD. Frequency and extent of visual field defects corresponded with anatomic location of ODD and peripapillary RNFL thickness, suggesting increased axonal damage in patients with superficial ODD.

  9. [Facial nerve neurinomas].

    Science.gov (United States)

    Sokołowski, Jacek; Bartoszewicz, Robert; Morawski, Krzysztof; Jamróz, Barbara; Niemczyk, Kazimierz

    2013-01-01

    Evaluation of diagnostic, surgical technique, treatment results facial nerve neurinomas and its comparison with literature was the main purpose of this study. Seven cases of patients (2005-2011) with facial nerve schwannomas were included to retrospective analysis in the Department of Otolaryngology, Medical University of Warsaw. All patients were assessed with history of the disease, physical examination, hearing tests, computed tomography and/or magnetic resonance imaging, electronystagmography. Cases were observed in the direction of potential complications and recurrences. Neurinoma of the facial nerve occurred in the vertical segment (n=2), facial nerve geniculum (n=1) and the internal auditory canal (n=4). The symptoms observed in patients were analyzed: facial nerve paresis (n=3), hearing loss (n=2), dizziness (n=1). Magnetic resonance imaging and computed tomography allowed to confirm the presence of the tumor and to assess its staging. Schwannoma of the facial nerve has been surgically removed using the middle fossa approach (n=5) and by antromastoidectomy (n=2). Anatomical continuity of the facial nerve was achieved in 3 cases. In the twelve months after surgery, facial nerve paresis was rated at level II-III° HB. There was no recurrence of the tumor in radiological observation. Facial nerve neurinoma is a rare tumor. Currently surgical techniques allow in most cases, the radical removing of the lesion and reconstruction of the VII nerve function. The rate of recurrence is low. A tumor of the facial nerve should be considered in the differential diagnosis of nerve VII paresis. Copyright © 2013 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z.o.o. All rights reserved.

  10. Auditory agnosia.

    Science.gov (United States)

    Slevc, L Robert; Shell, Alison R

    2015-01-01

    Auditory agnosia refers to impairments in sound perception and identification despite intact hearing, cognitive functioning, and language abilities (reading, writing, and speaking). Auditory agnosia can be general, affecting all types of sound perception, or can be (relatively) specific to a particular domain. Verbal auditory agnosia (also known as (pure) word deafness) refers to deficits specific to speech processing, environmental sound agnosia refers to difficulties confined to non-speech environmental sounds, and amusia refers to deficits confined to music. These deficits can be apperceptive, affecting basic perceptual processes, or associative, affecting the relation of a perceived auditory object to its meaning. This chapter discusses what is known about the behavioral symptoms and lesion correlates of these different types of auditory agnosia (focusing especially on verbal auditory agnosia), evidence for the role of a rapid temporal processing deficit in some aspects of auditory agnosia, and the few attempts to treat the perceptual deficits associated with auditory agnosia. A clear picture of auditory agnosia has been slow to emerge, hampered by the considerable heterogeneity in behavioral deficits, associated brain damage, and variable assessments across cases. Despite this lack of clarity, these striking deficits in complex sound processing continue to inform our understanding of auditory perception and cognition. © 2015 Elsevier B.V. All rights reserved.

  11. Time computations in anuran auditory systems

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    Gary J Rose

    2014-05-01

    Full Text Available Temporal computations are important in the acoustic communication of anurans. In many cases, calls between closely related species are nearly identical spectrally but differ markedly in temporal structure. Depending on the species, calls can differ in pulse duration, shape and/or rate (i.e., amplitude modulation, direction and rate of frequency modulation, and overall call duration. Also, behavioral studies have shown that anurans are able to discriminate between calls that differ in temporal structure. In the peripheral auditory system, temporal information is coded primarily in the spatiotemporal patterns of activity of auditory-nerve fibers. However, major transformations in the representation of temporal information occur in the central auditory system. In this review I summarize recent advances in understanding how temporal information is represented in the anuran midbrain, with particular emphasis on mechanisms that underlie selectivity for pulse duration and pulse rate (i.e., intervals between onsets of successive pulses. Two types of neurons have been identified that show selectivity for pulse rate: long-interval cells respond well to slow pulse rates but fail to spike or respond phasically to fast pulse rates; conversely, interval-counting neurons respond to intermediate or fast pulse rates, but only after a threshold number of pulses, presented at optimal intervals, have occurred. Duration-selectivity is manifest as short-pass, band-pass or long-pass tuning. Whole-cell patch recordings, in vivo, suggest that excitation and inhibition are integrated in diverse ways to generate temporal selectivity. In many cases, activity-related enhancement or depression of excitatory or inhibitory processes appear to contribute to selective responses.

  12. Fiber

    Science.gov (United States)

    ... meals instead of white rice. Add beans (kidney, black, navy, and pinto) to rice dishes for even more fiber. Spice up salads with berries and almonds, chickpeas, cooked artichokes, and beans (kidney, black, navy, or pinto). Use whole-grain (corn or ...

  13. Cortical perfusion response to an electrical stimulation of the auditory nerve in profoundly deaf patients: Study with technetium-99m hexamethylpropylene amine oxime single photon emission tomography

    International Nuclear Information System (INIS)

    Le Scao, Y.; Robier, A.; Beuter, P.; Baulieu, J.L.; Pourcelot, L.

    1992-01-01

    Brain activation procedures associated with single photon emission tomography (SPET) have recently been developed in healthy controls and diseased patients in order to help in their diagnosis and treatment. We investigated the effects of a promontory test (PT) on the cerebral distribution of technetium-99m hexamethyl-propylene amine oxime ( 99m Tc-HMPAO) in 7 profoundly deaf patients, 6 PT+ and PT-. The count variation in the temporal lobe was calculated on 6 coronal slices using the ratio (R stimulation -R deprivation )/R deprivation where R=counts in the temporal lobe was observed in all patients and was higher in all patients with PT+ than in the patient with PT-. The problems of head positioning and resolution of the system were taken into account, and we considered that the maximal count increment was related to the auditory cortex response to the stimulus. Further clinical investigations with high-resolution systems have to be performed in order to validate this presurgery test in cochlear implant assessment. (orig.)

  14. Cortical perfusion response to an electrical stimulation of the auditory nerve in profoundly deaf patients: Study with technetium-99m hexamethylpropylene amine oxime single photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Le Scao, Y.; Robier, A.; Beuter, P. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Otorhinolaryngology); Baulieu, J.L.; Pourcelot, L. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Nuclear Medicine)

    1992-04-01

    Brain activation procedures associated with single photon emission tomography (SPET) have recently been developed in healthy controls and diseased patients in order to help in their diagnosis and treatment. We investigated the effects of a promontory test (PT) on the cerebral distribution of technetium-99m hexamethyl-propylene amine oxime ({sup 99m}Tc-HMPAO) in 7 profoundly deaf patients, 6 PT+ and PT-. The count variation in the temporal lobe was calculated on 6 coronal slices using the ratio (R{sub stimulation}-R{sub deprivation})/R{sub deprivation} where R=counts in the temporal lobe was observed in all patients and was higher in all patients with PT+ than in the patient with PT-. The problems of head positioning and resolution of the system were taken into account, and we considered that the maximal count increment was related to the auditory cortex response to the stimulus. Further clinical investigations with high-resolution systems have to be performed in order to validate this presurgery test in cochlear implant assessment. (orig.).

  15. Cortical perfusion response to an electrical stimulation of the auditory nerve in profoundly deaf patients: study with technetium-99m hexamethylpropylene amine oxime single photon emission tomography.

    Science.gov (United States)

    Le Scao, Y; Robier, A; Baulieu, J L; Beutter, P; Pourcelot, L

    1992-01-01

    Brain activation procedures associated with single photon emission tomography (SPET) have recently been developed in healthy controls and diseased patients in order to help in their diagnosis and treatment. We investigated the effects of a promontory test (PT) on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) in 7 profoundly deaf patients, 6 PT+ and one PT-. The count variation in the temporal lobe was calculated on 6 coronal slices using the ratio (Rstimulation-Rdeprivation)/Rdeprivation where R = counts in the temporal lobe/whole-brain count. A count increase in the temporal lobe was observed in all patients and was higher in all patients with PT+ than in the patient with PT-. The problems of head positioning and resolution of the system were taken into account, and we considered that the maximal count increment was related to the auditory cortex response to the stimulus. Further clinical investigations with high-resolution systems have to be performed in order to validate this presurgery test in cochlear implant assessment.

  16. Análise da camada de fibras nervosas da retina em portadores de enxaqueca com aura Retinal nerve fiber layer measurements in patients with migraine with aura

    Directory of Open Access Journals (Sweden)

    Felipe Andrade Medeiros

    2001-10-01

    Full Text Available Objetivo: Avaliar as possíveis alterações na camada de fibras nervosas da retina (CFNR em pacientes com enxaqueca com aura, detectada por meio da polarimetria de varredura a laser. Métodos: Vinte pacientes com enxaqueca com aura e vinte indivíduos normais foram estudados. Os critérios de inclusão para os dois grupos compreenderam: idade de pelo menos 18 anos; ausência de história de doenças oculares, exceto erro refracional ou estrabismo; e ausência de história familiar de hipertensão ocular ou glaucoma. Foram excluídos pacientes com erro refracional maior que 5 DE e/ou 2 DC; acuidade visual corrigida menor que 20/40; pressão intra-ocular maior que 21 mmHg; discos ópticos anômalos ou com escavação maior que 0,5 ou assimetria de escavação maior que 0,2; ou com presença de doenças retinianas concomitantes. Os pacientes foram submetidos a exame de campo visual (Humphrey 30-2 e análise da CFNR com a polarimetria a laser (GDx - Nerve Fiber Analyzer. Um olho de cada paciente foi randomizado para análise estatística. Resultados: Nenhum dos pacientes do grupo controle apresentou defeitos de campo visual. Nove olhos (45% dos pacientes com enxaqueca tiveram anormalidades de campo visual além de 95% do intervalo de confiança do normal, como indicado pelos índices MD, CPSD ou GHT. Os valores de retardo no setor superior da CFNR dos pacientes com enxaqueca foram significativamente menor que no grupo controle (p=0,005. Não houve diferença significativa entre os valores de retardo dos dois grupos nas medidas globais e nos setores inferior, nasal e temporal. Conclusão: As medidas de retardo obtidas com a polarimetria a laser foram significativamente menores na porção superior da CFNR dos pacientes com enxaqueca com aura, sugerindo possível dano isquêmico às fibras nervosas, relacionadas à enxaqueca.Purpose: To evaluate the possible alterations of the retinal nerve fiber layer (RNFL, as detected by scanning laser polarimetry

  17. Comparative data on SD-OCT for the retinal nerve fiber layer and retinal macular thickness in a large cohort with Marfan syndrome.

    Science.gov (United States)

    Xu, WanWan; Kurup, Sudhi P; Fawzi, Amani A; Durbin, Mary K; Maumenee, Irene H; Mets, Marilyn B

    2017-01-01

    To report the distribution of macular and optic nerve topography in the eyes of individuals with Marfan syndrome aged 8-56 years using spectral domain optical coherence tomography (SD-OCT). Thirty-three patients with Marfan syndrome underwent a full eye examination including slit-lamp biomicroscopy, indirect ophthalmoscopy, and axial length measurement; and SD-OCT measurements of the retinal nerve fiber layer (RNFL) and macular thickness. For patients between the ages of 8 and 12 years, the average RNFL thickness is 98 ± 9 μm, the vertical cup to disc (C:D) ratio is 0.50 ± 0.10, the central subfield thickness (CST) is 274 ± 38 μm, and the macular volume is 10.3 ± 0.6 mm 3 . For patients between the ages of 13 and 17 years, the average RNFL is 86 ± 16 μm, the vertical C:D ratio is 0.35 ± 0.20, the CST is 259 ± 15 μm, and the macular volume is 10.1 ± 0.5 mm 3 . For patients 18 years or older, the average RNFL is 89 ± 12 μm, the vertical C:D ratio is 0.46 ± 0.18, the CST is 262 ± 20 μm, and the macular volume is 10.2 ± 0.4 mm 3 . When the average RNFL data are compared to a normative, age-adjusted database, 6 of 33 (18%) were thinner than the 5% limit. This study reports the distribution of SD-OCT data for patients with Marfan syndrome. Compared to a normative database, 18% of eyes with Marfan syndrome had RNFL thickness < 5% of the population.

  18. Contribución de fibras mielínicas provenientes de los nervios espinales lumbares L4, L5 y L6 al nervio ciático de rata adulta y sus ramas principales Contribution of myelunated fibers from spinal L4, L5 and L6 nerves to the sciatic nerve and its main branches in the adult rat

    Directory of Open Access Journals (Sweden)

    Hernán Hurtado

    2000-04-01

    Full Text Available El nervio ciático de la rata está formado por los nervios espinales (ne lumbares L4, L5 y L6. Sin embargo, aún no se ha definido el aporte en fibras mielínicas de estos nervios espinales a lo largo del tronco nervioso. En este estudio se transectaron selectivamente los NE L4, L5 y L4-L5. Luego de una semana se disecaron los nervios ciático, tibial, sural y peroneal. Estas muestras se fijaron y procesaron para microscopía óptica y a partir de cortes coloreados con azul de toluidina se contaron las fibras mielínicas degeneradas y normales. L4 contribuyó con fibras mielínicas principalmente al nervio peroneal y L5 a los nervios ciático, tibial y sural. En general, el aporte de L6 fue menor y variable a lo largo del tronco nervioso comparado con las otras dos ramas espinales. Nuestros resultados brindan información valiosa para posteriores estudios que busquen correlacionar la contribución de los nervios espinales que componen el ciático y sus ramas principales con la función de la extremidad inferior. The rat sciatic nerve is composed by the L4, L5 and L6 lumbar spinal nerves. However, the contribution in myelinated fibers originating from these nerves along this nervous trunk has not yet been defined. In the present study, the L4, L5 and L4-L5 spinal nerves were selectively transected. After one week the sciatic, tibial, sural and peroneal nerves were dissected. These samples were fixed and processed for optical microscopy, and both degenerated and normal myelinated fibers were counted in toluidine blue-stained semi-thin sections. L4 contributed with myelinated fibers mainly to the peroneal nerve, and L5 to the sciatic, tibial and sural nerves. In general, the contribution of L6 was smaller and variable along the nervous trunk in comparison to the other two spinal branches. Our results give key information for further studies looking to correlate the contribution of spinal nerves making part of the sciatic nerve and its main

  19. Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry.

    Science.gov (United States)

    Wang, Xiao-en; Wang, Xiao-yu; Gu, Yang-shun; Huang, Zhu

    2013-01-01

    Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG). This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated. Twenty-two eyes with POAG and HM (spherical equivalent (SE) between -6.0 and -12.0 D) were evaluated, and 22 eyes with HM were used for comparison. Characteristic retinal nerve fiber layer (RNFL) thickness profiles in patients with POAG and HM were examined using optical coherence tomography (OCT) and scanning laser polarimetry with variable corneal compensation (GDxVCC), and the diagnostic capabilities of these imaging modalities were compared. RNFL parameters evaluated included superior average (Savg-GDx), inferior average (Iavg-GDx), temporal-superior-nasal- inferior-temporal (TSNIT) average, and nerve fiber indicator (NFI) on GDxVCC and superior average (Savg-OCT), inferior average (Iavg-OCT), nasal average (Navg-OCT), temporal average (Tavg-OCT), and average thickness (AvgThick-OCT) on OCT (fast RNFL scan). Visual field testing was performed and defects were evaluated using mean defect (MD) and pattern standard deviation (PSD). The RNFL parameters (P < 0.05) significantly different between groups included Savg-GDx, Iavg-GDx, TSNIT average, NFI, Savg-OCT, Iavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT (r = 0.778), TSNIT average and MD (r = 0.749), AvgThick-OCT and MD (r = 0.647), TSNIT average and PSD (r = -0.756), and AvgThick-OCT and PSD (r = -0.784). The area under the receiver operating characteristic curve (AUROC) values of TSNIT average, Savg-GDx, Iavg-GDx, NFI, Savg-OCT, Iavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the

  20. Electric-acoustic interactions in the hearing cochlea: single fiber recordings.

    Science.gov (United States)

    Tillein, J; Hartmann, R; Kral, A

    2015-04-01

    The present study investigates interactions of simultaneous electric and acoustic stimulation in single auditory nerve fibers in normal hearing cats. First, the auditory nerve was accessed with a microelectrode and response areas of single nerve fibers were determined for acoustic stimulation. Second, response thresholds to extracochlear sinusoidal electric stimulation using ball electrodes positioned at the round window were measured. Third, interactions that occurred with combined electric-acoustic stimulation were investigated in two areas: (1) the spectral domain (frequency response areas) and (2) the temporal domain (phase-locking to each stimulus) at moderate stimulus intensities (electric: 6 dB re threshold, acoustic: 20-40 dB re threshold at the characteristic frequency, CF). For fibers responding to both modalities responses to both electric and acoustic stimulation could be clearly identified. CFs, thresholds, and bandwidth (Q10dB) of acoustic responses were not significantly affected by simultaneous electric stimulation. Phase-locking of electric responses decreased in the presence of acoustic stimulation. Indication for electric stimulation of inner hair cells with 125 and 250 Hz were observed. However, these did not disturb the acoustic receptive fields of auditory nerve fibers. There was a trade-off between these responses when the intensities of the stimulation were varied: Relatively more intense stimulation dominated less intense stimulation. The scarcity of interaction between the different stimulus modalities demonstrates the ability of electric-acoustic stimulation to transfer useful information through both stimulation channels at the same time despite cochlear electrophonic effects. Application of 30 Hz electric stimulation resulted in a strong suppression of acoustic activity in the anodic phase of the stimulus. An electric stimulation like this might thus be used to control acoustic responses. This article is part of a Special Issue

  1. Alteração da camada de fibras nervosas da retina em usuários crônicos de cloroquina Retinal nerve fiber layer alteration in chronic users of chloroquine

    Directory of Open Access Journals (Sweden)

    Daniela de Almeida Lyra Antunes

    2005-04-01

    Full Text Available OBJETIVOS: Avaliar a camada de fibras nervosas da retina (CFN por meio da polarimetria a laser, em pacientes em uso crônico de cloroquina. MÉTODOS: Foram estudados 44 olhos de 22 pacientes em uso de cloroquina por doenças reumatológicas, por pelo menos um ano. Como controle, foram incluídos vinte indivíduos sem uso de cloroquina com idade, gênero e raça similares. Foram excluídos os pacientes que apresentavam história familiar de hipertensão ocular ou glaucoma. Ambos os olhos foram submetidos à análise da camada de fibras nervosas da retina, com o aparelho GDx® Nerve Fiber Analyser, pelo mesmo examinador. RESULTADOS: Nos usuários crônicos de cloroquina, verificou-se alteração em mais de dois parâmetros do GDx em 28 olhos (63,6%. Ocorreu também alteração no gráfico "Deviation from normal" com perda de fibras nervosas em 11 olhos (25%. Quando comparado com o grupo controle, os parâmetros que demonstraram diferença estatisticamente significante foram: Superior Ratio, Inferior Ratio, Superior Nasal, Elipse Modulation, The Number, Superior Average e Superior Integral. Houve também associação estatisticamente significante entre o tempo de uso de cloroquina e perda da CFN. CONCLUSÕES: Comprovou-se a associação entre o uso crônico da cloroquina e a alteração da CFN detectada pelo GDx. Desta forma, esses resultados podem contribuir para o diagnóstico precoce da perda de fibras nervosas na retinopatia por cloroquina.PURPOSES: To evaluate the retina nerve fiber layer by laser polarimetry in patients in chronic use of chloroquine. METHODS: Forty-four eyes of twenty-two patients were studied. These were in use of chloroquine due to rheumatic diseases during at least one year. As a control group, twenty patients without use of chloroquine with similar characteristics (age, gender and race were included. Patients who had a family history of ocular hypertension or glaucoma were not included in this group. Both eyes were

  2. The combined effects of forward masking by noise and high click rate on monaural and binaural human auditory nerve and brainstem potentials.

    Science.gov (United States)

    Pratt, Hillel; Polyakov, Andrey; Bleich, Naomi; Mittelman, Naomi

    2004-07-01

    To study effects of forward masking and rapid stimulation on human monaurally- and binaurally-evoked brainstem potentials and suggest their relation to synaptic fatigue and recovery and to neuronal action potential refractoriness. Auditory brainstem evoked potentials (ABEPs) were recorded from 12 normally- and symmetrically hearing adults, in response to each click (50 dB nHL, condensation and rarefaction) in a train of nine, with an inter-click interval of 11 ms, that followed a white noise burst of 100 ms duration (50 dB nHL). Sequences of white noise and click train were repeated at a rate of 2.89 s(-1). The interval between noise and first click in the train was 2, 11, 22, 44, 66 or 88 ms in different runs. ABEPs were averaged (8000 repetitions) using a dwell time of 25 micros/address/channel. The binaural interaction components (BICs) of ABEPs were derived and the single, centrally located equivalent dipoles of ABEP waves I and V and of the BIC major wave were estimated. The latencies of dipoles I and V of ABEP, their inter-dipole interval and the dipole magnitude of component V were significantly affected by the interval between noise and clicks and by the serial position of the click in the train. The latency and dipole magnitude of the major BIC component were significantly affected by the interval between noise and clicks. Interval from noise and the click's serial position in the train interacted to affect dipole V latency, dipole V magnitude, BIC latencies and the V-I inter-dipole latency difference. Most of the effects were fully apparent by the first few clicks in the train, and the trend (increase or decrease) was affected by the interval between noise and clicks. The changes in latency and magnitude of ABEP and BIC components with advancing position in the click train and the interactions of click position in the train with the intervals from noise indicate an interaction of fatigue and recovery, compatible with synaptic depletion and replenishing

  3. Acellular Nerve Allografts in Peripheral Nerve Regeneration: A Comparative Study

    Science.gov (United States)

    Moore, Amy M.; MacEwan, Matthew; Santosa, Katherine B.; Chenard, Kristofer E.; Ray, Wilson Z.; Hunter, Daniel A.; Mackinnon, Susan E.; Johnson, Philip J.

    2011-01-01

    Background Processed nerve allografts offer a promising alternative to nerve autografts in the surgical management of peripheral nerve injuries where short deficits exist. Methods Three established models of acellular nerve allograft (cold-preserved, detergent-processed, and AxoGen® -processed nerve allografts) were compared to nerve isografts and silicone nerve guidance conduits in a 14 mm rat sciatic nerve defect. Results All acellular nerve grafts were superior to silicone nerve conduits in support of nerve regeneration. Detergent-processed allografts were similar to isografts at 6 weeks post-operatively, while AxoGen®-processed and cold-preserved allografts supported significantly fewer regenerating nerve fibers. Measurement of muscle force confirmed that detergent-processed allografts promoted isograft-equivalent levels of motor recovery 16 weeks post-operatively. All acellular allografts promoted greater amounts of motor recovery compared to silicone conduits. Conclusions These findings provide evidence that differential processing for removal of cellular constituents in preparing acellular nerve allografts affects recovery in vivo. PMID:21660979

  4. Retinal nerve fiber layer and ganglion cell complex thickness assessment in patients with Alzheimer disease and mild cognitive impairment. Preliminary results

    Directory of Open Access Journals (Sweden)

    A. S. Tiganov

    2014-07-01

    Full Text Available Purpose: to investigate the retinal nerve fiber layer (RNFL and the macular ganglion cell complex (GCC in patients with Alzheimer`s disease and mild cognitive impairment.Methods: this study included 10 patients (20 eyes with Alzheimer`s disease, 10 patients with mild cognitive impairment and 10 age- and sex-matched healthy controls that had no history of dementia. All the subjects underwent psychiatric examination, including the Mini-Mental State Examination (MMSE, and complete ophthalmological examination, comprising optical coherence tomography and scanning laser polarimetry.Results: there was a significant decrease in GCC thickness in patients with Alzheimer`s disease compared to the control group, global loss volume of ganglion cells was higher than in control group. there was no significant difference among the groups in terms of RNFL thickness. Weak positive correlation of GCC thickness and MMSE results was observed.Conclusion: Our data confirm the retinal involvement in Alzheimer`s disease, as reflected by loss of ganglion cells. Further studies will clear up the role and contribution of dementia in pathogenesis of optic neuropathy.

  5. The Effect of LASIK Procedure on Peripapillary Retinal Nerve Fiber Layer and Macular Ganglion Cell-Inner Plexiform Layer Thickness in Myopic Eyes

    Directory of Open Access Journals (Sweden)

    Maja Zivkovic

    2017-01-01

    Full Text Available Purpose. To evaluate the effect of applied suction during microkeratome-assisted laser in situ keratomileusis (LASIK procedure on peripapillary retinal nerve fiber layer (RNFL thickness as well as macular ganglion cell-inner plexiform layer (GC-IPL thickness. Methods. 89 patients (124 eyes with established myopia range from −3.0 to −8.0 diopters and no associated ocular diseases were included in this study. RNFL and GC-IPL thickness measurements were performed by spectral domain optical coherence tomography (SD OCT one day before LASIK and at 1 and 6 months postoperatively. Results. Mean RNFL thickness prior to LASIK was 93.86±12.17 μm while the first month and the sixth month postoperatively were 94.01±12.04 μm and 94.46±12.27 μm, respectively. Comparing results, there is no significant difference between baseline, one month, and six months postoperatively for mean RNFL (p>0.05. Mean GC-IPL thickness was 81.70±7.47 μm preoperatively with no significant difference during the follow-up period (82.03±7.69 μm versus 81.84±7.64 μm; p>0.05. Conclusion. RNFL and GC-IPL complex thickness remained unaffected following LASIK intervention.

  6. Subtle changes in myelination due to childhood experiences: label-free microscopy to infer nerve fibers morphology and myelination in brain (Conference Presentation)

    Science.gov (United States)

    Gasecka, Alicja; Tanti, Arnaud; Lutz, Pierre-Eric; Mechawar, Naguib; Cote, Daniel C.

    2017-02-01

    Adverse childhood experiences have lasting detrimental effects on mental health and are strongly associated with impaired cognition and increased risk of developing psychopathologies. Preclinical and neuroimaging studies have suggested that traumatic events during brain development can affect cerebral myelination particularly in areas and tracts implicated in mood and emotion. Although current neuroimaging techniques are quite powerful, they lack the resolution to infer myelin integrity at the cellular level. Recently demonstrated coherent Raman microscopy has accomplished cellular level imaging of myelin sheaths in the nervous system. However, a quantitative morphometric analysis of nerve fibers still remains a challenge. In particular, in brain, where fibres exhibit small diameters and varying local orientation. In this work, we developed an automated myelin identification and analysis method that is capable of providing a complete picture of axonal myelination and morphology in brain samples. This method performs three main procedures 1) detects molecular anisotropy of membrane phospholipids based on polarization resolved coherent Raman microscopy, 2) identifies regions of different molecular organization, 3) calculates morphometric features of myelinated axons (e.g. myelin thickness, g-ratio). We applied this method to monitor white matter areas from suicides adults that suffered from early live adversity and depression compared to depressed suicides adults and psychiatrically healthy controls. We demonstrate that our method allows for the rapid acquisition and automated analysis of neuronal networks morphology and myelination. This is especially useful for clinical and comparative studies, and may greatly enhance the understanding of processes underlying the neurobiological and psychopathological consequences of child abuse.

  7. The Impact of Lens Opacity on SD-OCT Retinal Nerve Fiber Layer and Bruch's Membrane Opening Measurements Using the Anatomical Positioning System (APS).

    Science.gov (United States)

    Mauschitz, Matthias M; Roth, Felix; Holz, Frank G; Breteler, Monique M B; Finger, Robert P

    2017-05-01

    To evaluate the impact of lens opacity on retinal nerve fiber layer thickness (RNFLT) and Bruch's membrane opening (BMO) measurements. Fifty-nine randomly selected patients without any other relevant ocular pathology undergoing elective routine cataract surgery in two specialized eye clinics were enrolled. RNFLT, BMO area, and BMO minimum rim width (BMO-MRW) were assessed with the Heidelberg Engineering Spectralis OCT using the anatomical positioning system (APS) prior to and 1 day after cataract surgery using a ring scan at different eccentricities of the disc (3.5, 4.1 and 4.7 mm). Lens opacity was quantified using densitometry based on Scheimpflug images (Oculus Pentacam AXL). RNFLT, BMO area, and BMO-MRW were virtually identical before and following removal of the cataractous lens. This held when assessed overall, within the six sectors for the 3.5-mm scan, or at any other eccentricity. Baseline RNFLT was not associated with lens opacity. Using the APS, RNFLT remained unchanged following cataract surgery, contrary to results reported by previous studies. Our results imply that the APS may have contributed to more precise spectral-domain optical coherence measurements, minimizing the influence of cataract on RNFLT and BMO assessments in our cohort.

  8. Changes in Macular Retinal Layers and Peripapillary Nerve Fiber Layer Thickness after 577-nm Pattern Scanning Laser in Patients with Diabetic Retinopathy.

    Science.gov (United States)

    Shin, Ji Soo; Lee, Young Hoon

    2017-12-01

    The aim of this study was to evaluate the changes in thickness of each macular retinal layer, the peripapillary retinal nerve fiber layer (RNFL), and central macular thickness (CMT) after 577-nm pattern scanning laser (PASCAL) photocoagulation in patients with diabetic retinopathy. This retrospective study included 33 eyes with diabetic retinopathy that underwent 577-nm PASCAL photocoagulation. Each retinal layer thickness, peripapillary RNFL thickness, and CMT were measured by spectral-domain optical coherence tomography before 577-nm PASCAL photocoagulation, as well as at 1, 6, and 12 months after 577-nm PASCAL photocoagulation. Computerized intraretinal segmentation of optical coherence tomography was performed to identify the thickness of each retinal layer. The average thickness of the RNFL, ganglion cell layer, inner plexiform layer, inner nuclear layer, inner retinal layer, and CMT at each follow-up increased significantly from baseline (p 0.05). Each macular retinal layer and CMT had a tendency to increase for one year after 577-nm PASCAL photocoagulation, whereas the average thickness of retinal pigment epithelium decreased at one-year follow-up compared to the baseline. Although an increase in peripapillary RNFL thickness was observed one month after 577-nm PASCAL photocoagulation, there were no significant changes at the one-year follow-up compared to the baseline. © 2017 The Korean Ophthalmological Society

  9. Variations of retinal nerve fiber layer thickness and ganglion cell-inner plexiform layer thickness according to the torsion direction of optic disc.

    Science.gov (United States)

    Lee, Kang Hoon; Kim, Chan Yun; Kim, Na Rae

    2014-02-20

    To examine the relationship between the optic disc torsion and peripapillary retinal nerve fiber layer (RNFL) thickness through a comparison with the macular ganglion cell inner plexiform layer complex (GCIPL) thickness measured by Cirrus optical coherence tomography (OCT). Ninety-four eyes of 94 subjects with optic disc torsion and 114 eyes of 114 subjects without optic disc torsion were enrolled prospectively. The participants underwent fundus photography and OCT imaging in peripapillary RNFL mode and macular GCIPL mode. The participants were divided into groups according to the presence or absence of optic disc torsion. The eyes with optic disc torsion were further divided into supranasal torsion and inferotemporal torsion groups according to the direction of optic disc torsion. The mean RNFL and GCIPL thicknesses for the quadrants and subsectors were compared. The superior and inferior peak locations of the RNFL were also measured according to the torsion direction. The temporal RNFL thickness was significantly thicker in inferotemporal torsion, whereas the GCIPL thickness at all segments was unaffected. The inferotemporal optic torsion had more temporally positioned superior peak locations of the RNFL than the nontorsion and supranasal-torted optic disc. Thickening of the temporal RNFL with a temporal shift in the superior peak within the eyes with inferotemporal optic disc torsion can lead to interpretation errors. The ganglion cell analysis algorithm can assist in differentiating eyes with optic disc torsion.

  10. Neuro-otological and peripheral nerve involvement in Fabry disease

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    Sergio Carmona

    2017-07-01

    Full Text Available Fabry disease (FD is an X-linked lysosomal storage disease, with multisystemic glycosphingolipids deposits. Neuro-otological involvement leading to hearing loss and vestibular dysfunctions has been described, but there is limited information about the frequency, site of lesion, or the relationship with peripheral neuropathy. The aim was to evaluate the presence of auditory and vestibular symptoms, and assess neurophysiological involvement of the VIII cranial nerve, correlating these findings with clinical and neurophysiological features of peripheral neuropathy. We studied 36 patients with FD with a complete neurological and neuro-otological evaluation including nerve conduction studies, quantitative sensory testing (to evaluate small fiber by warm and cold threshold detection and cold and heat pain, vestibular evoked myogenic potentials, videonistagmography, audiometry and brainstem auditory evoked potentials. Neuro-otologic symptoms included hearing loss (22.2%, vertigo (27.8% or both (25%. An involvement of either cochlear or vestibular function was identified in most patients (75%. In 70% of our patients the involvement of both cochlear and vestibular function could not be explained by a neural or vascular mechanism. Small fiber neuropathy was identified in 77.7%. There were no significant associations between neurootological and QST abnormalities. Neuro-otologic involvement is frequent and most likely under-recognized in patients with FD. It lacks a specific neural or vascular pattern, suggesting multi-systemic, end organ damage. Small fiber neuropathy is an earlier manifestation of FD, but there is no correlation between the development of neuropathy and neuro-otological abnormalities.

  11. Auditory Neuropathy

    Science.gov (United States)

    ... children and adults with auditory neuropathy. Cochlear implants (electronic devices that compensate for damaged or nonworking parts ... and Drug Administration: Information on Cochlear Implants Telecommunications Relay Services Your Baby's Hearing Screening News Deaf health ...

  12. Pinched Nerve

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    ... You are here Home » Disorders » All Disorders Pinched Nerve Information Page Pinched Nerve Information Page What research is being done? Within the NINDS research programs, pinched nerves are addressed primarily through studies associated with pain ...

  13. Auditory hallucinations.

    Science.gov (United States)

    Blom, Jan Dirk

    2015-01-01

    Auditory hallucinations constitute a phenomenologically rich group of endogenously mediated percepts which are associated with psychiatric, neurologic, otologic, and other medical conditions, but which are also experienced by 10-15% of all healthy individuals in the general population. The group of phenomena is probably best known for its verbal auditory subtype, but it also includes musical hallucinations, echo of reading, exploding-head syndrome, and many other types. The subgroup of verbal auditory hallucinations has been studied extensively with the aid of neuroimaging techniques, and from those studies emerges an outline of a functional as well as a structural network of widely distributed brain areas involved in their mediation. The present chapter provides an overview of the various types of auditory hallucination described in the literature, summarizes our current knowledge of the auditory networks involved in their mediation, and draws on ideas from the philosophy of science and network science to reconceptualize the auditory hallucinatory experience, and point out directions for future research into its neurobiologic substrates. In addition, it provides an overview of known associations with various clinical conditions and of the existing evidence for pharmacologic and non-pharmacologic treatments. © 2015 Elsevier B.V. All rights reserved.

  14. Naftidrofuryl affects neurite regeneration by injured adult auditory neurons.

    Science.gov (United States)

    Lefebvre, P P; Staecker, H; Moonen, G; van de Water, T R

    1993-07-01

    Afferent auditory neurons are essential for the transmission of auditory information from Corti's organ to the central auditory pathway. Auditory neurons are very sensitive to acute insult and have a limited ability to regenerate injured neuronal processes. Therefore, these neurons appear to be a limiting factor in restoration of hearing function following an injury to the peripheral auditory receptor. In a previous study nerve growth factor (NGF) was shown to stimulate neurite repair but not survival of injured auditory neurons. In this study, we have demonstrated a neuritogenesis promoting effect of naftidrofuryl in an vitro model for injury to adult auditory neurons, i.e. dissociated cell cultures of adult rat spiral ganglia. Conversely, naftidrofuryl did not have any demonstrable survival promoting effect on these in vitro preparations of injured auditory neurons. The potential uses of this drug as a therapeutic agent in acute diseases of the inner ear are discussed in the light of these observations.

  15. Evidence Suggesting that the Buccal and Zygomatic Branches of the Facial Nerve May Contain Parasympathetic Secretomotor Fibers to the Parotid Gland by Means of Communications from the Auriculotemporal Nerve.

    Science.gov (United States)

    Tansatit, Tanvaa; Apinuntrum, Prawit; Phetudom, Thavorn

    2015-12-01

    The auriculotemporal nerve is one of the peripheral nerves that communicates with the facial nerve. However, the function of these communications is poorly understood. Details of how these communications form and connect with each other are still unclear. In addition, a reliable anatomical landmark for locating these communications during surgery has not been sufficiently described. Microdissection was performed on 20 lateral hemifaces of 10 soft-embalmed cadavers to investigate facial-auriculotemporal nerve communications with emphasis on determining their function. The auriculotemporal nerve was identified in the retromandibular space and traced towards its terminations. The communicating branches were followed and the anatomical relationships to surrounding structures observed. The auriculotemporal nerve is suspended above the maxillary artery in the dense retromandibular fascia behind the mandibular ramus. It forms a knot and fans out, providing multiple branches in all directions in the sagittal plane. Inferiorly, it connects the maxillary periarterial plexus, while minute branches supply the temporomandibular joint anteriorly. The larger branches mainly communicate with the branches of the temporofacial division of the facial nerve, and the auricular branches enter the fascia of the auricular cartilage posteriorly. The temporal branches and occasionally the zygomatic branches arise superiorly to distribute within the temporoparietal fascia. The auriculotemporal nerve forms the parotid retromandibular plexus through two types of communication. It sends one to three branches to join the zygomatic and buccal branches of the facial nerve at the branching area of the temporofacial division. It also communicates with the periarterial plexus of the superficial temporal and maxillary arteries. This plexus continues anteriorly along the branches of the facial nerve and the periarterial plexus of the transverse facial artery as the parotid periductal autonomic plexus

  16. Streptozocin-induced type-1 diabetes mellitus results in decreased density of CGRP sensory and TH sympathetic nerve fibers that are positively correlated with bone loss at the mouse femoral neck.

    Science.gov (United States)

    Enríquez-Pérez, Iris A; Galindo-Ordoñez, Karla E; Pantoja-Ortíz, Christian E; Martínez-Martínez, Arisaí; Acosta-González, Rosa I; Muñoz-Islas, Enriqueta; Jiménez-Andrade, Juan M

    2017-08-10

    Type-1 diabetes mellitus (T1DM) results in loss of innervation in some tissues including epidermis and retina; however, the effect on bone innervation is unknown. Likewise, T1DM results in pathological bone loss and increased risk of fracture. Thus, we quantified the density of calcitonin gene-related peptide (CGRP + ) sensory and tyrosine hydroxylase (TH + ) sympathetic nerve fibers and determined the association between the innervation density and microarchitecture of trabecular bone at the mouse femoral neck. Ten weeks-old female mice received 5 daily administrations of streptozocin (i.p. 50mg/kg) or citrate (control group). Twenty weeks later, femurs were analyzed by microCT and processed for immunohistochemistry. Confocal microscopy analysis revealed that mice with T1DM had a significant loss of both CGRP + and TH + nerve fibers in the bone marrow at the femoral neck. Likewise, microCT analysis revealed a significant decrease in the trabecular bone mineral density (tBMD), bone volume/total volume ratio (BV/TB), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) in mice with T1DM as compared to control mice. Analysis of correlation revealed a positive and significant association between density of CGRP + or TH + nerve fibers with tBMD, BV/TV, Tb.Th and Tb.Sp, but not with trabecular number (there was a positive association only for CGRP + ) and degree of anisotropy (DA). This study suggests an interaction between sensory and sympathetic nervous system and T1DM-induced bone loss. Identification of the factors involved in the loss of CGRP + sensory and TH + sympathetic fibers and how they regulate bone loss may result in new avenues to treat T1DM-related osteoporosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Influence of optic disc size on the diagnostic performance of macular ganglion cell complex and peripapillary retinal nerve fiber layer analyses in glaucoma

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    Cordeiro DV

    2011-09-01

    Full Text Available Daniela Valença Cordeiro1, Verônica Castro Lima1,2, Dinorah P Castro1,3, Leonardo C Castro1,3, Maria Angélica Pacheco2, Jae Min Lee2, Marcelo I Dimantas2, Tiago Santos Prata1,21Department of Ophthalmology, Federal University of São Paulo, São Paulo, 2Hospital Medicina dos Olhos, São Paulo, 3Centro Brasileiro de Especialidades Oftalmológicas, Araraquara, BrazilAim: To evaluate the influence of optic disc size on the diagnostic accuracy of macular ganglion cell complex (GCC and conventional peripapillary retinal nerve fiber layer (pRNFL analyses provided by spectral domain optical coherence tomography (SD-OCT in glaucoma.Methods: Eighty-two glaucoma patients and 30 healthy subjects were included. All patients underwent GCC (7 × 7 mm macular grid, consisting of RNFL, ganglion cell and inner plexiform layers and pRNFL thickness measurement (3.45 mm circular scan by SD-OCT. One eye was randomly selected for analysis. Initially, receiver operating characteristic (ROC curves were generated for different GCC and pRNFL parameters. The effect of disc area on the diagnostic accuracy of these parameters was evaluated using a logistic ROC regression model. Subsequently, 1.5, 2.0, and 2.5 mm2 disc sizes were arbitrarily chosen (based on data distribution and the predicted areas under the ROC curves (AUCs and sensitivities were compared at fixed specificities for each.Results: Average mean deviation index for glaucomatous eyes was -5.3 ± 5.2 dB. Similar AUCs were found for the best pRNFL (average thickness = 0.872 and GCC parameters (average thickness = 0.824; P = 0.19.The coefficient representing disc area in the ROC regression model was not statistically significant for average pRNFL thickness (-0.176 or average GCC thickness (0.088; P ≥ 0.56. AUCs for fixed disc areas (1.5, 2.0, and 2.5 mm2 were 0.904, 0.891, and 0.875 for average pRNFL thickness and 0.834, 0.842, and 0.851 for average GCC thickness, respectively. The highest sensitivities – at

  18. Retinal nerve fiber layer thickness measured by optical coherence tomography in Chinese teenagers aged from 13 years old to 18 years old

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    Yu-Ming Zhang

    2014-04-01

    Full Text Available AIM: To establish a reference range of retinal nerve fiber layer(RNFLthickness by optical coherence tomography(OCTin Chinese teenagers aged from 13 to 18 years old, and investigate its relationship with age, eye side, gender, and ethnic group.METHODS: A total of 402 eyes from 201 normal Chinese aged from 13 to 18 years old were recruited for this study. Optic disk with 3.4mm diameter circle in different global average, quadrant and part-time bit retinal nerve fiber layer thickness(RNFLTwas measured by RNFL thickness average analysis program. Their RNFLT at different part-time bit, quadrant and global average RNFLT around the disc were measured by OCT with 3.4mm diameter circle, using the RNFL thickness average analysis program. The data was analyzed with SPSS statistical 19.0. The influences of several factors(such as age, eye side, gender, and ethnic groupon RNFLT were also analyzed.RESULTS: The global average RNFLT at 13, 14, 15, 16, 17, 18 years old was 108.32±9.42μm, 109.23±9.67μm, 110.36±11.14μm, 111.27±10.21μm, 109.23±9.67μm, 112.11±8.83μm respectively. RNFLT of right eyes was 109.82±8.93μm and of left eyes was 110.33±9.89μm. All of the male's average RNFLT was 110.14±10.02μm, and all of the female's average RNFLT was 109.96±11.22μm. The average RNFLT of Han nationality was 110.22±9.31μm and of non-Han nationality was 109.87±8.65μm. The average RNFLT of all was 110.02±9.87μm, the RNFLT at the superior, nasal, inferior and temporal quadrant was 146.56 ±18.88μm, 76.49±13.28μm, 136.64±16.29μm, 82.01±12.55μm respectively. There was no significant difference in gender, eye side, and ethnic group(all PCONCLUSION: This study has established a normal standard reference of RNFLT and its related indexes by OCT in Chinese teenagers aged 13-18 years old. Gender, age, eye side, and ethnic group have no effect on their RNFLT, which has significant difference with adult's data. And for the diagnosis and follow-up of

  19. Measurement of retinal nerve fiber layer thickness in eyes with optic disc swelling by using scanning laser polarimetry and optical coherence tomography.

    Science.gov (United States)

    Hata, Masayuki; Miyamoto, Kazuaki; Oishi, Akio; Kimura, Yugo; Nakagawa, Satoko; Horii, Takahiro; Yoshimura, Nagahisa

    2014-01-01

    The retinal nerve fiber layer thickness (RNFLT) in patients with optic disc swelling of different etiologies was compared using scanning laser polarimetry (SLP) and spectral-domain optical coherence tomography (OCT). Forty-seven patients with optic disc swelling participated in the cross-sectional study. Both GDx SLP (enhanced corneal compensation) and Spectralis spectral-domain OCT measurements of RNFLT were made in 19 eyes with papilledema (PE), ten eyes with optic neuritis (ON), and 18 eyes with nonarteritic anterior ischemic optic neuropathy (NAION) at the neuro-ophthalmology clinic at Kyoto University Hospital. Differences in SLP (SLP-RNFLT) and OCT (OCT-RNFLT) measurements among different etiologies were investigated. No statistical differences in average OCT-RNFLT among PE, ON, and NAION patients were noted. Average SLP-RNFLT in NAION patients was smaller than in PE (P<0.01) or ON (P=0.02) patients. When RNFLT in each retinal quadrant was compared, no difference among etiologies was noted on OCT, but on SLP, the superior quadrant was thinner in NAION than in PE (P<0.001) or ON (P=0.001) patients. Compared with age-adjusted normative data of SLP-RNFLT, average SLP-RNFLT in PE (P<0.01) and ON (P<0.01) patients was greater. Superior SLP-RNFLT in NAION patients was smaller (P=0.026). The ratio of average SLP-RNFLT to average OCT-RNFLT was smaller in NAION than in PE (P=0.001) patients. In the setting of RNFL thickening, despite increased light retardance in PE and ON eyes, SLP revealed that NAION eyes have less retardance, possibly associated with ischemic axonal loss.

  20. The ISNT Rule: How Often Does It Apply to Disc Photographs and Retinal Nerve Fiber Layer Measurements in the Normal Population?

    Science.gov (United States)

    Poon, Linda Yi-Chieh; Solá-Del Valle, David; Turalba, Angela V; Falkenstein, Iryna A; Horsley, Michael; Kim, Julie H; Song, Brian J; Takusagawa, Hana L; Wang, Kaidi; Chen, Teresa C

    2017-12-01

    To determine what percentage of normal eyes follow the ISNT rule, and whether ISNT rule variants may be more generalizable to the normal population. Cross-sectional study. Setting: Institutional setting. Total of 110 normal subjects. Neuroretinal rim assessments from disc photographs and retinal nerve fiber layer (RNFL) thickness measurements from spectral-domain optical coherence tomography. The percentages of subjects that obeyed the ISNT rule and its variants. The ISNT rule is only valid for 37.0% of disc photograph rim assessments and 43.8% of RNFL measurements. Deviation of the nasal sector from the expected ISNT pattern was a major cause for the ISNT rule not being obeyed for both rim and RNFL assessments. Specifically, 10.9% of subjects had wider nasal rims than the inferior rims, 29.4% had wider nasal rims than the superior rims, 14.7% had narrower nasal rims than the temporal rims, and 42.9% had thinner nasal RNFLs compared to the temporal quadrant. Exclusion of the nasal quadrant from the ISNT rule significantly increased the validity of ISNT variant rules, with 70.9% and 76.4% of disc photographs following the IST rule and the IS rule, respectively. Similarly, for RNFL thickness, 70.9% and 71.8% of patients followed the IST and IS rule, respectively. The ISNT rule is only valid for about a third of disc photographs and less than half of RNFL measurements in normal patients. ISNT rule variants, such as the IST and IS rule, may be considered, as they are valid in more than 70% of patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Asymmetry of Peak Thicknesses between the Superior and Inferior Retinal Nerve Fiber Layers for Early Glaucoma Detection: A Simple Screening Method.

    Science.gov (United States)

    Bae, Hyoung Won; Lee, Sang Yeop; Kim, Sangah; Park, Chan Keum; Lee, Kwanghyun; Kim, Chan Yun; Seong, Gong Je

    2018-01-01

    To assess whether the asymmetry in the peripapillary retinal nerve fiber layer (pRNFL) thickness between superior and inferior hemispheres on optical coherence tomography (OCT) is useful for early detection of glaucoma. The patient population consisted of Training set (a total of 60 subjects with early glaucoma and 59 normal subjects) and Validation set (30 subjects with early glaucoma and 30 normal subjects). Two kinds of ratios were employed to measure the asymmetry between the superior and inferior pRNFL thickness using OCT. One was the ratio of the superior to inferior peak thicknesses (peak pRNFL thickness ratio; PTR), and the other was the ratio of the superior to inferior average thickness (average pRNFL thickness ratio; ATR). The diagnostic abilities of the PTR and ATR were compared to the color code classification in OCT. Using the optimal cut-off values of the PTR and ATR obtained from the Training set, the two ratios were independently validated for diagnostic capability. For the Training set, the sensitivities/specificities of the PTR, ATR, quadrants color code classification, and clock-hour color code classification were 81.7%/93.2%, 71.7%/74.6%, 75.0%/93.2%, and 75.0%/79.7%, respectively. The PTR showed a better diagnostic performance for early glaucoma detection than the ATR and the clock-hour color code classification in terms of areas under the receiver operating characteristic curves (AUCs) (0.898, 0.765, and 0.773, respectively). For the Validation set, the PTR also showed the best sensitivity and AUC. The PTR is a simple method with considerable diagnostic ability for early glaucoma detection. It can, therefore, be widely used as a new screening method for early glaucoma. © Copyright: Yonsei University College of Medicine 2018

  2. Repetitive Acupuncture Point Treatment with Diluted Bee Venom Relieves Mechanical Allodynia and Restores Intraepidermal Nerve Fiber Loss in Oxaliplatin-Induced Neuropathic Mice.

    Science.gov (United States)

    Yeo, Ji-Hee; Yoon, Seo-Yeon; Kwon, Soon-Keun; Kim, Sol-Ji; Lee, Jang-Hern; Beitz, Alvin J; Roh, Dae-Hyun

    2016-03-01

    The chemotherapeutic agent, oxaliplatin, produces a robust painful neuropathy that results in the loss of intraepidermal nerve fibers (IENFs). We have previously reported that an acupuncture point (acupoint) injection of diluted bee venom (DBV) produces a temporary antiallodynic effect in oxaliplatin-induced neuropathic mice. Herein we show a significant long-lasting antinociceptive effect of repetitive DBV acupoint treatment on oxaliplatin-induced mechanical allodynia and a significant reduction in the loss of IENFs. DBV (0.1 mg/kg, subcutaneous) was administered once a day for 18 days beginning on day 15 after oxaliplatin injection. Immunohistochemistry for IENF was performed on the glabrous skin of the hind paw footpad using the pan-neuronal marker, protein gene product 9.5. A temporary increase in mechanical threshold was observed 60 minutes after a single DBV injection into the Zusanli acupoint, and this effect was enhanced over time with repetitive DBV treatments. The basal mechanical threshold before daily DBV injection also increased from day 7 after DBV injections, and peaked at day 14 after DBV treatment. Moreover, the oxaliplatin-induced loss of IENFs was significantly reduced in mice treated repetitively with DBV. Repetitive pretreatment with the α-2 adrenoceptor antagonist, yohimbine, (5 mg/kg, subcutaneous) completely prevented the antiallodynic effects and the increase in IENFs observed in mice treated repetitively with DBV. We showed that repetitive acupoint stimulation with DBV gradually and significantly reduced oxaliplatin-induced mechanical allodynia and restored the loss of IENFs in neuropathic mice via an α-2 adrenoceptor mechanism. Collectively, results of this study suggest that repetitive acupoint treatment with DBV can be a potential strategy for the management of chemotherapy-induced neuropathy. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  3. Normative Database and Color-code Agreement of Peripapillary Retinal Nerve Fiber Layer and Macular Ganglion Cell-inner Plexiform Layer Thickness in a Vietnamese Population.

    Science.gov (United States)

    Perez, Claudio I; Chansangpetch, Sunee; Thai, Andy; Nguyen, Anh-Hien; Nguyen, Anwell; Mora, Marta; Nguyen, Ngoc; Lin, Shan C

    2018-06-05

    Evaluate the distribution and the color probability codes of the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in a healthy Vietnamese population and compare them with the original color-codes provided by the Cirrus spectral domain OCT. Cross-sectional study. We recruited non-glaucomatous Vietnamese subjects and constructed a normative database for peripapillary RNFL and macular GCIPL thickness. The probability color-codes for each decade of age were calculated. We evaluated the agreement with Kappa coefficient (κ) between OCT color probability codes with Cirrus built-in original normative database and the Vietnamese normative database. 149 eyes of 149 subjects were included. The mean age of enrollees was 60.77 (±11.09) years, with a mean spherical equivalent of +0.65 (±1.58) D and mean axial length of 23.4 (±0.87) mm. Average RNFL thickness was 97.86 (±9.19) microns and average macular GCIPL was 82.49 (±6.09) microns. Agreement between original and adjusted normative database for RNFL was fair for average and inferior quadrant (κ=0.25 and 0.2, respectively); and good for other quadrants (range: κ=0.63-0.73). For macular GCIPL κ agreement ranged between 0.39 and 0.69. After adjusting with the normative Vietnamese database, the percent of yellow and red color-codes increased significantly for peripapillary RNFL thickness. Vietnamese population has a thicker RNFL in comparison with Cirrus normative database. This leads to a poor color-code agreement in average and inferior quadrant between the original and adjusted database. These findings should encourage to create a peripapillary RNFL normative database for each ethnicity.

  4. Thickness of the Macula, Retinal Nerve Fiber Layer, and Ganglion Cell Layer in the Epiretinal Membrane: The Repeatability Study of Optical Coherence Tomography.

    Science.gov (United States)

    Lee, Haeng-Jin; Kim, Min-Su; Jo, Young-Joon; Kim, Jung-Yeul

    2015-07-01

    To analyze the repeatability of measurements of the thicknesses of the macula, retinal nerve fiber layer (RNFL), and ganglion cell inner plexiform layer (GCIPL) using spectral-domain optical coherence tomography (SD-OCT) in the epiretinal membrane (ERM). The prospective study analyzed patients who visited our retinal clinic from June 2013 to January 2014. An experienced examiner measured the thicknesses twice using macular cube 512 × 128 and optic disc cube 200 × 200 scans. The repeatability of the thicknesses of the macula, RNFL, and GCIPL were compared using the intraclass correlation coefficient (ICC) of two groups based on the central macular thickness (group A, ≤ 450 μm; group B, > 450 μm). A total of 88 patients were analyzed. The average thicknesses of the central macula, RNFL, and GCIPL were 256.5, 96.6, and 84.4 μm, respectively, in the normal fellow eye and 412.3, 94.6, and 56.7 μm in the affected eye. The ICCs of the central macula, RNFL, and GCIPL were 0.995, 0.994, and 0.996, respectively, for the normal fellow eye and 0.991, 0.973, and 0.881 for the affected eye. The average thicknesses of the central macula, RNFL, and GCIPL in group A were 360.9, 93.5, and 63.4 μm, respectively, and the ICCs were 0.997, 0.987, and 0.995. The thicknesses in group B were 489.5, 96.2, and 46.6 μm, respectively, and the ICCs were 0.910, 0.942, and 0.603, significantly lower repeatability compared with group A (P macula.

  5. Prevention of Paclitaxel-induced allodynia by Minocycline: Effect on loss of peripheral nerve fibers and infiltration of macrophages in rats

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    Xin Wen-Jun

    2010-11-01

    Full Text Available Abstract Background Although paclitaxel is a frontline antineoplastic agent for treatment of solid tumors, the paclitaxel-evoked pain syndrome is a serious problem for patients. There is currently no valid drug to prevent or treat the paclitaxel-induced allodynia, partly due to lack of understanding regarding the cellular mechanism. Studies have shown that minocycline, an inhibitor of microglia/macrophage, prevented neuropathic pain and promoted neuronal survival in animal models of neurodegenerative disease. Recently, Cata et al also reported that minocycline inhibited allodynia induced by low-dose paclitaxel (2 mg/kg in rats, but the mechanism is still unclear. Results Here, we investigate by immunohistochemistry the change of intraepidermal nerve fiber (IENF in the hind paw glabrous skin, expression of macrophage and activating transcription factor 3 (ATF3 in DRG at different time points after moderate-dose paclitaxel treatment (cumulative dose 24 mg/kg; 3 × 8 mg/kg in rats. Moreover, we observe the effect of minocycline on the IENF, macrophages and ATF3. The results showed that moderate-dose paclitaxel induced a persisted, gradual mechanical allodynia, which was accompanied by the loss of IENF in the hind paw glabrous skin and up-regulation of macrophages and ATF3 in DRG in rats. The expressions of ATF3 mainly focus on the NF200-positive cells. More importantly, we observed that pretreatment of minocycline at dose of 30 mg/kg or 50 mg/kg, but not 5 mg/kg, prevented paclitaxel-evoked allodynia. The evidence from immunohistochemistry showed that 30 mg/kg minocycline rescued the degeneration of IENF, attenuated infiltration of macrophages and up-regulation of ATF3 induced by paclitaxel treatment in rats. Conclusions Minocycline prevents paclitaxel-evoked allodynia, likely due to its inhibition on loss of IENF, infiltration of macrophages and up-regulation of ATF3 in rats. The finding might provide potential target for preventing paclitaxel

  6. Prevalence of ulnar-to-median nerve motor fiber anastomosis (Riché-Cannieu communicating branch) in hand: An electrophysiological study

    Science.gov (United States)

    Ahadi, Tannaz; Raissi, Gholam Reza; Yavari, Masood; Majidi, Lobat

    2016-01-01

    Background: Two main muscles studied in the hand for evaluation of median nerve injuries are opponens pollicis (OP) and abductor pollicis brevis (APB). However, Riché-Cannieu communicating branch (RCCB) may limit the use of these muscles in electrodiagnosis. This condition is confusing in the case of median nerve injuries. This study was conducted to evaluate the prevalence of RCCB. Methods: Twenty-three consecutive cases of complete median nerve injury were studied. Evoked responses via stimulation of median and ulnar nerves in the wrist and recording with needle in the thenar area were studied. Results: Of the patients, 82.6% exhibited RCCB. In 14 (60.8%) cases the OP and in 19(82.6%) cases APB was supplied by the ulnar nerve. Conclusion: RCCB was detected to be 60.8% in OP and 82.6% in APB, so OP is preferable to APB in the study of median nerve. PMID:27390694

  7. Facial Nerve Schwannoma of the Cerebellopontine Angle: A Diagnostic Challenge

    OpenAIRE

    Lassaletta, Luis; Roda, José María; Frutos, Remedios; Patrón, Mercedes; Gavilán, Javier

    2002-01-01

    Facial nerve schwannomas are rare lesions that may involve any segment of the facial nerve. Because of their rarity and the lack of a consistent clinical and radiological pattern, facial nerve schwannomas located at the cerebellopontine angle (CPA) and internal auditory canal (IAC) represent a diagnostic and therapeutic challenge for clinicians. In this report, a case of a CPA/IAC facial nerve schwannoma is presented. Contemporary diagnosis and management of this rare lesion are analyzed.

  8. A novel method of lengthening the accessory nerve for direct coaptation during nerve repair and nerve transfer procedures.

    Science.gov (United States)

    Tubbs, R Shane; Maldonado, Andrés A; Stoves, Yolanda; Fries, Fabian N; Li, Rong; Loukas, Marios; Oskouian, Rod J; Spinner, Robert J

    2018-01-01

    OBJECTIVE The accessory nerve is frequently repaired or used for nerve transfer. The length of accessory nerve available is often insufficient or marginal (under tension) for allowing direct coaptation during nerve repair or nerve transfer (neurotization), necessitating an interpositional graft. An attractive maneuver would facilitate lengthening of the accessory nerve for direct coaptation. The aim of the present study was to identify an anatomical method for such lengthening. METHODS In 20 adult cadavers, the C-2 or C-3 connections to the accessory nerve were identified medial to the sternocleidomastoid (SCM) muscle and the anatomy of the accessory nerve/cervical nerve fibers within the SCM was documented. The cervical nerve connections were cut. Lengths of the accessory nerve were measured. Samples of the cut C-2 and C-3 nerves were examined using immunohistochemistry. RESULTS The anatomy and adjacent neural connections within the SCM are complicated. However, after the accessory nerve was "detethered" from within the SCM and following transection, the additional length of the accessory nerve increased from a mean of 6 cm to a mean of 10.5 cm (increase of 4.5 cm) after cutting the C-2 connections, and from a mean of 6 cm to a mean length of 9 cm (increase of 3.5 cm) after cutting the C-3 connections. The additional length of accessory nerve even allowed direct repair of an infraclavicular target (i.e., the proximal musculocutaneous nerve). The cervical nerve connections were shown not to contain motor fibers. CONCLUSIONS An additional length of the accessory nerve made available in the posterior cervical triangle can facilitate direct repair or neurotization procedures, thus eliminating the need for an interpositional nerve graft, decreasing the time/distance for regeneration and potentially improving clinical outcomes.

  9. Análise da camada de fibras nervosas da retina em usuários crônicos do tabaco e álcool Analysis of retinal nerve fiber layer in chronic tobacco and alcohol users

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Ramos de Lima

    2006-06-01

    Full Text Available OBJETIVOS: Avaliar a camada de fibras nervosas (CFN da retina, através da polarimetria a laser (GDx, em usuários crônicos do tabaco e álcool. MÉTODOS: Foram estudados 46 olhos de 23 indivíduos alcoólatras e tabagistas crônicos triados do Ambulatório de Oftalmologia da Fundação Altino Ventura (grupo estudo. Como grupo controle foram incluídos 32 olhos de 16 voluntários não-usuários do álcool e tabaco, com idade, gênero e raça similares, também triados da Fundação Altino Ventura. Ambos os olhos de todos os indivíduos foram submetidos à análise da camada de fibras nervosas da retina, com aparelho "GDx nerve fiber analyses" pelo mesmo examinador. RESULTADOS: No gráfico Deviation from normal, no grupo estudo ocorreu perda de fibras nervosas da retina em 43,4%, enquanto que no grupo controle houve perda apenas em 18,7%. Quanto aos parâmetros que analisam o GDx, quando comparados o grupo estudo com o grupo controle, observou-se diferença estatisticamente significante nos parâmetros: Ellipse modulation, Inferior ratio e Max modulation. CONCLUSÕES: Os dados comprovam a associação entre o uso crônico do tabaco e álcool e a alteração na camada de fibras nervosas da retina, podendo contribuir para o diagnóstico precoce desta neuropatia.PURPOSES: To evaluate the retinal nerve fiber layer using GDx in chronic alcohol and tobacco users. METHODS: Twenty-three chronic alcohol and tobacco users were studied (study group. As a control group, sixteen volunteers without use of alcohol and tobacco with similar characteristics (age, gender and race were included. Both eyes were tested for analysis of the retinal nerve fiber layer with GDx. RESULTS: There was alteration in the Deviation from normal graph with a loss of nerve fibers in 43.4% of patients in the study group. In the control group this alteration was observed in 14 eyes (18.7%. As regards the parameters that allow comparison between the study and control groups there was

  10. THICKNESS OF THE MACULA, RETINAL NERVE FIBER LAYER, AND GANGLION CELL-INNER PLEXIFORM LAYER IN THE AGE-RELATED MACULAR DEGENERATION: The Repeatability Study of Spectral Domain Optical Coherence Tomography.

    Science.gov (United States)

    Shin, Il-Hwan; Lee, Woo-Hyuk; Lee, Jong-Joo; Jo, Young-Joon; Kim, Jung-Yeul

    2018-02-01

    To determine the repeatability of measuring the thickness of the central macula, retinal nerve fiber layer, and ganglion cell-inner plexiform layer (GC-IPL) using spectral domain optical coherence tomography (Cirrus HD-OCT) in eyes with age-related macular degeneration. One hundred and thirty-four eyes were included. The measurement repeatability was assessed by an experienced examiner who performed two consecutive measurements using a 512 × 128 macular cube scan and a 200 × 200 optic disk cube scan. To assess changes in macular morphology in patients with age-related macular degeneration, the patients were divided into the following three groups according to the central macular thickness (CMT): A group, CMT 300 μm. Measurement repeatability was assessed using test-retest variability, a coefficient of variation, and an intraclass correlation coefficient. The mean measurement repeatability for the central macular, retinal nerve fiber layer, and GC-IPL thickness was high in the B group. The mean measurement repeatability for both the central macula and retinal nerve fiber layer thickness was high in the A and C groups, but was lower for the GC-IPL thickness. The measurement repeatability for GC-IPL thickness was high in the B group, but low in the A group and in the C group. The automated measurement repeatability for GC-IPL thickness was significantly lower in patients with age-related macular degeneration with out of normal CMT range. The effect of changes in macular morphology should be considered when analyzing GC-IPL thicknesses in a variety of ocular diseases.

  11. Omental pedicle transposition and suture repair of peripheral nerve ...

    African Journals Online (AJOL)

    Abu wael

    This study aimed to compare the effectiveness of omental pedicle transposition and ... Assessment of the nerve regeneration was based on functional (motor and sensory), ..... peripheral nerve fibers regenerating after crush, multiple crush, and.

  12. The nerve endings of the acetabular labrum.

    Science.gov (United States)

    Kim, Y T; Azuma, H

    1995-11-01

    The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzuki's silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.

  13. Short-term observations of the regenerative potential of injured proximal sensory nerves crossed with distal motor nerves

    Directory of Open Access Journals (Sweden)

    Xiu-xiu Zhang

    2017-01-01

    Full Text Available Motor nerves and sensory nerves conduct signals in different directions and function in different ways. In the surgical treatment of peripheral nerve injuries, the best prognosis is obtained by keeping the motor and sensory nerves separated and repairing the nerves using the suture method. However, the clinical consequences of connections between sensory and motor nerves currently remain unknown. In this study, we analyzed the anatomical structure of the rat femoral nerve, and observed the motor and sensory branches of the femoral nerve in the quadriceps femoris. After ligation of the nerves, the proximal end of the sensory nerve was connected with the distal end of the motor nerve, followed by observation of the changes in the newly-formed regenerated nerve fibers. Acetylcholinesterase staining was used to distinguish between the myelinated and unmyelinated motor and sensory nerves. Denervated muscle and newly formed nerves were compared in terms of morphology, electrophysiology and histochemistry. At 8 weeks after connection, no motor nerve fibers were observed on either side of the nerve conduit and the number of nerve fibers increased at the proximal end. The proportion of newly-formed motor and sensory fibers was different on both sides of the conduit. The area occupied by autonomic nerves in the proximal regenerative nerve was limited, but no distinct myelin sheath was visible in the distal nerve. These results confirm that sensory and motor nerves cannot be effectively connected. Moreover, the change of target organ at the distal end affects the type of nerves at the proximal end.

  14. Influence of optic disc size on the diagnostic performance of macular ganglion cell complex and peripapillary retinal nerve fiber layer analyses in glaucoma.

    Science.gov (United States)

    Cordeiro, Daniela Valença; Lima, Verônica Castro; Castro, Dinorah P; Castro, Leonardo C; Pacheco, Maria Angélica; Lee, Jae Min; Dimantas, Marcelo I; Prata, Tiago Santos

    2011-01-01

    To evaluate the influence of optic disc size on the diagnostic accuracy of macular ganglion cell complex (GCC) and conventional peripapillary retinal nerve fiber layer (pRNFL) analyses provided by spectral domain optical coherence tomography (SD-OCT) in glaucoma. Eighty-two glaucoma patients and 30 healthy subjects were included. All patients underwent GCC (7 × 7 mm macular grid, consisting of RNFL, ganglion cell and inner plexiform layers) and pRNFL thickness measurement (3.45 mm circular scan) by SD-OCT. One eye was randomly selected for analysis. Initially, receiver operating characteristic (ROC) curves were generated for different GCC and pRNFL parameters. The effect of disc area on the diagnostic accuracy of these parameters was evaluated using a logistic ROC regression model. Subsequently, 1.5, 2.0, and 2.5 mm(2) disc sizes were arbitrarily chosen (based on data distribution) and the predicted areas under the ROC curves (AUCs) and sensitivities were compared at fixed specificities for each. Average mean deviation index for glaucomatous eyes was -5.3 ± 5.2 dB. Similar AUCs were found for the best pRNFL (average thickness = 0.872) and GCC parameters (average thickness = 0.824; P = 0.19). The coefficient representing disc area in the ROC regression model was not statistically significant for average pRNFL thickness (-0.176) or average GCC thickness (0.088; P ≥ 0.56). AUCs for fixed disc areas (1.5, 2.0, and 2.5 mm(2)) were 0.904, 0.891, and 0.875 for average pRNFL thickness and 0.834, 0.842, and 0.851 for average GCC thickness, respectively. The highest sensitivities - at 80% specificity for average pRNFL (84.5%) and GCC thicknesses (74.5%) - were found with disc sizes fixed at 1.5 mm(2) and 2.5 mm(2). Diagnostic accuracy was similar between pRNFL and GCC thickness parameters. Although not statistically significant, there was a trend for a better diagnostic accuracy of pRNFL thickness measurement in cases of smaller discs. For GCC analysis, an inverse effect

  15. Analysis of Macular and Retinal Nerve Fiber Layer Thickness in Children with Refractory Amblyopia after Femtosecond Laser-assisted Laser In situ Keratomileusis: A Retrospective Study.

    Science.gov (United States)

    Zhao, Peng-Fei; Zhou, Yue-Hua; Zhang, Jing; Wei, Wen-Bin

    2017-09-20

    Localized macular edema and retinal nerve fiber layer (RNFL) thinning have been reported shortly after laser in situ keratomileusis (LASIK) in adults. However, it is still unclear how LASIK affects the retina of children. This study aimed to investigate the macular retina and RNFL thickness in children with refractive amblyopia who underwent femtosecond laser-assisted LASIK (FS-LASIK). In this study, we included 56 eyes of 32 patients with refractive amblyopia who underwent FS-LASIK in our hospital from January 2012 to December 2016. Foveal (foveal center retinal, parafoveal retinal, and perifoveal), macular inner retinal (superior and inferior), and peripapillary RNFL thicknesses (superior, inferior, temporal, and nasal) were measured using Fourier-domain optical coherence tomography before surgery and 1 day, 3 days, and 1 week after surgery. We divided these patients into three groups based on their refractive error: High myopic group with 22 eyes (equivalent sphere, >6.00 D), mild myopic group with 19 eyes (equivalent sphere, 0-6.00 D), and hyperopic group with 15 eyes (equivalent sphere, >+0.50 D). We compared the macular retina and RNFL thickness before and after LASIK. A paired simple t-test was used for data analysis. One week after surgery, the visual acuity for all 56 eyes of the 32 patients reached their preoperative best-corrected vision. Visual acuity improved two lines or better for 31% of the patients. The residual refractive errors in 89% of the patients were within ±0.5 D. In the high myopic group, the foveal center retinal and parafoveal retinal thicknesses were thicker 1 day and 3 days after surgery than before surgery (t = 2.689, P = 0.012; t = 2.383, P = 0.018, respectively); no significant difference was found 1 week after surgery (P > 0.05). The foveal center retinal and parafoveal retinal thicknesses were greater 1 day after surgery than they were before surgery (P = 0.000 and P = 0.005, respectively) in the mild myopic and hyperopic groups

  16. Scaffoldless tissue-engineered nerve conduit promotes peripheral nerve regeneration and functional recovery after tibial nerve injury in rats

    Institute of Scientific and Technical Information of China (English)

    Aaron M. Adams; Keith W. VanDusen; Tatiana Y. Kostrominova; Jacob P. Mertens; Lisa M. Larkin

    2017-01-01

    Damage to peripheral nerve tissue may cause loss of function in both the nerve and the targeted muscles it innervates. This study compared the repair capability of engineered nerve conduit (ENC), engineered fibroblast conduit (EFC), and autograft in a 10-mm tibial nerve gap. ENCs were fabricated utilizing primary fibroblasts and the nerve cells of rats on embryonic day 15 (E15). EFCs were fabricated utilizing primary fi-broblasts only. Following a 12-week recovery, nerve repair was assessed by measuring contractile properties in the medial gastrocnemius muscle, distal motor nerve conduction velocity in the lateral gastrocnemius, and histology of muscle and nerve. The autografts, ENCs and EFCs reestablished 96%, 87% and 84% of native distal motor nerve conduction velocity in the lateral gastrocnemius, 100%, 44% and 44% of native specific force of medical gastrocnemius, and 63%, 61% and 67% of native medial gastrocnemius mass, re-spectively. Histology of the repaired nerve revealed large axons in the autograft, larger but fewer axons in the ENC repair, and many smaller axons in the EFC repair. Muscle histology revealed similar muscle fiber cross-sectional areas among autograft, ENC and EFC repairs. In conclusion, both ENCs and EFCs promot-ed nerve regeneration in a 10-mm tibial nerve gap repair, suggesting that the E15 rat nerve cells may not be necessary for nerve regeneration, and EFC alone can suffice for peripheral nerve injury repair.

  17. Presbycusis and auditory brainstem responses: a review

    Directory of Open Access Journals (Sweden)

    Shilpa Khullar

    2011-06-01

    Full Text Available Age-related hearing loss or presbycusis is a complex phenomenon consisting of elevation of hearing levels as well as changes in the auditory processing. It is commonly classified into four categories depending on the cause. Auditory brainstem responses (ABRs are a type of early evoked potentials recorded within the first 10 ms of stimulation. They represent the synchronized activity of the auditory nerve and the brainstem. Some of the changes that occur in the aging auditory system may significantly influence the interpretation of the ABRs in comparison with the ABRs of the young adults. The waves of ABRs are described in terms of amplitude, latencies and interpeak latency of the different waves. There is a tendency of the amplitude to decrease and the absolute latencies to increase with advancing age but these trends are not always clear due to increase in threshold with advancing age that act a major confounding factor in the interpretation of ABRs.

  18. The longitudinal epineural incision and complete nerve transection method for modeling sciatic nerve injury

    Directory of Open Access Journals (Sweden)

    Xing-long Cheng

    2015-01-01

    Full Text Available Injury severity, operative technique and nerve regeneration are important factors to consider when constructing a model of peripheral nerve injury. Here, we present a novel peripheral nerve injury model and compare it with the complete sciatic nerve transection method. In the experimental group, under a microscope, a 3-mm longitudinal incision was made in the epineurium of the sciatic nerve to reveal the nerve fibers, which were then transected. The small, longitudinal incision in the epineurium was then sutured closed, requiring no stump anastomosis. In the control group, the sciatic nerve was completely transected, and the epineurium was repaired by anastomosis. At 2 and 4 weeks after surgery, Wallerian degeneration was observed in both groups. In the experimental group, at 8 and 12 weeks after surgery, distinct medullary nerve fibers and axons were observed in the injured sciatic nerve. Regular, dense myelin sheaths were visible, as well as some scarring. By 12 weeks, the myelin sheaths were normal and intact, and a tight lamellar structure was observed. Functionally, limb movement and nerve conduction recovered in the injured region between 4 and 12 weeks. The present results demonstrate that longitudinal epineural incision with nerve transection can stably replicate a model of Sunderland grade IV peripheral nerve injury. Compared with the complete sciatic nerve transection model, our method reduced the difficulties of micromanipulation and surgery time, and resulted in good stump restoration, nerve regeneration, and functional recovery.

  19. Sound and vibration sensitivity of VIIIth nerve fibers in the frogs Leptodactylus albilabris and Rana pipiens pipiens

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Narins, P M

    1993-01-01

    and to sound from 40 dB SPL by increasing their spike rate. Best frequencies (BFs) ranged from 60 to 900 Hz, and only fibers with BFs below 500 Hz responded to vibrations. The fibers had identical BF's for sound and vibration. The saccular fibers had BFs ranging from 10 to 80 Hz with 22 fibers having BFs at 40......-50 Hz. The fibers responded to sound from 70 dB SPL and to vibrations from 0.01 cm/s2. 3. No differences in sensitivity, tuning or phase-locking were found between the two species, except that most BP-fibers in R. pipiens pipiens had BFs from 1.2 to 1.4 kHz, whereas those in L. albilabris had BFs from 2...

  20. Terminal nerve: cranial nerve zero

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Duque Parra

    2006-12-01

    Full Text Available It has been stated, in different types of texts, that there are only twelve pairs of cranial nerves. Such texts exclude the existence of another cranial pair, the terminal nerve or even cranial zero. This paper considers the mentioned nerve like a cranial pair, specifying both its connections and its functional role in the migration of liberating neurons of the gonadotropic hormone (Gn RH. In this paper is also stated the hypothesis of the phylogenetic existence of a cerebral sector and a common nerve that integrates the terminal nerve with the olfactory nerves and the vomeronasals nerves which seem to carry out the odors detection function as well as in the food search, pheromone detection and nasal vascular regulation.

  1. Structural characteristics of the acquired optic disc pit and the rate of progressive retinal nerve fiber layer thinning in primary open-angle glaucoma.

    Science.gov (United States)

    Lee, Seung Hyen; Lee, Eun Ji; Kim, Tae-Woo

    2015-10-01

    The optic disc pit (ODP) has been considered a region of localized susceptibility to the damage of glaucoma. To determine whether the rate of retinal nerve fiber layer (RNFL) thinning differs according to the presence and structural characteristics of an ODP in primary open-angle glaucoma. We performed a prospective case-control study that included 163 eyes with primary open-angle glaucoma (83 with an ODP and 80 without an ODP) from Glaucoma Clinic of Seoul National University Bundang Hospital. Participants were enrolled from the ongoing Investigating Glaucoma Progression Study from January 1, 2012, through May 31, 2014. Mean (SD) follow-up was 3.32 (0.49) years (through May 31, 2014). Optic nerve heads underwent swept-source optical coherence tomography (OCT) to determine the presence of focal lamina cribrosa alteration and its structural characteristics. Eyes with and without photographic ODPs and corresponding microscopic laminar alterations were assigned to the ODP and non-ODP groups, respectively. The rates of progressive thinning of global and 6 sectoral spectral-domain OCT RNFL thicknesses were determined by linear regression and compared between the 2 groups. We used a general linear model to determine the factors associated with the rate of RNFL thinning; data obtained from September 21, 2009, through May 31, 2014, were used to calculate the rate of RNFL thinning. The relationship between the presence and structural characteristics of ODPs and the rate of progressive OCT RNFL thinning. Thinning of the RNFL was faster in the ODP group than in the non-ODP group in the global (mean [SD], -1.44 [1.31] vs -0.93 [1.10] [95% CI, -0.97 to -0.19] μm/y; P = .008), temporoinferior (mean [SD], -4.17 [4.15] vs -1.97 [3.26] [95% CI, -3.36 to -1.04] μm/y; P < .001), and temporal (mean [SD], -1.92 [2.62] vs -0.89 [1.62] [95% CI, -1.70 to -0.35] μm/y; P = .003) sectors. The rate of RNFL thinning was maximum in the temporoinferior sector (mean [SD], -4

  2. Cutaneous somatic and autonomic nerve TDP-43 deposition in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Ren, Yuting; Liu, Wenxiu; Li, Yifan; Sun, Bo; Li, Yanran; Yang, Fei; Wang, Hongfen; Li, Mao; Cui, Fang; Huang, Xusheng

    2018-05-26

    To evaluate the involvement of the sensory and autonomic nervous system in amyotrophic lateral sclerosis (ALS) and to determine whether TDP-43/pTDP-43 deposits in skin nerve fibers signify a valuable biomarker for ALS. Eighteen patients with ALS and 18 age- and sex-matched control subjects underwent physical examinations, in addition to donating skin biopsies from the distal leg. The density of epidermal, Meissner's corpuscle (MC), sudomotor, and pilomotor nerve fibers were measured. Confocal microscopy was used to determine the cutaneous somatic and autonomic nerve fiber density and TDP-43/pTDP-43 deposition. Intraepidermal nerve fiber density (IENFD) was reduced in individuals with ALS (P nerve fiber density (SGNFD) (P nerve fiber density (PNFD) (P nerve fibers may indicate an important role in the underlying pathogenesis of ALS. This observation might be used as a potential biomarker for diagnosing ALS.

  3. Análise da camada de fibras nervosas pelo GDx em pacientes pseudofácicos com opacidades da cápsula posterior Analysis of the nerve fiber layer using GDx in pseudophakic patients with posterior capsular opacification

    Directory of Open Access Journals (Sweden)

    Tatiana Azevedo Arraes

    2008-02-01

    Full Text Available OBJETIVO: Avaliar se a opacificação de cápsula posterior (OCP influenciaria na análise da camada de fibras nervosas pela polarimetria "scanning laser" (GDx. MÉTODOS: Trinta e sete pacientes pseudofácicos não glaucomatosos foram submetidos a análise da camada de fibras nervosas pelo GDx antes e após a realização de capsulotomia com Nd:YAG laser. RESULTADOS: Em cinco olhos, o GDx não conseguiu imagens aceitáveis pelos parâmetros de aquisição do aparelho. Em todos os outros, não foi observada diferença significante entre os valores médios das variáveis antes e após a realização da capsulotomia posterior. CONCLUSÃO: A presença de OCP em graus moderados e/ou quando há imagens aceitáveis em pacientes pseudofácicos não influencia o resultado da análise das imagens das fibras do nervo óptico pelo GDx. Apenas intensos graus de OCP que impeçam a obtenção de imagem analisável pelo aparelho inviabilizam o exame.PURPOSE: To evaluate if posterior capsule opacification (PCO would alter the analysis of nerve fiber layer using the scanning laser polarimetry (GDx. METHODS: Pseudophakic non-glaucomatosous eyes (37 patients underwent nerve fiber layer analysis using GDx before and after posterior capsulotomy with Nd:YAG Laser. RESULTS: In five eyes, GDx did not obtain acceptable images using the device's parameters of acquisition. In the others, mean variable values did not reach significant difference before and after posterior capsulotomy. CONCLUSION: Moderate degrees of PCO and/or acceptable images in pseudophakic patients do not alter the analysis of nerve fiber layer by GDx. Only intense degrees of PCO that hinder analyzable images make the examination impracticable.

  4. Nerve endings in the heart of teleosts.

    Science.gov (United States)

    Kumar, S

    1979-01-01

    The nerve endings in the heart of fishes were studied using silver impregnation techniques. The heart chambers are profusely innervated by the sympathetic, parasympathetic (vagal) and postganglionic fibers of the intracardiac ganglia situated at the sinuatrial and the atrioventricular junctions. The plexuses are composed of medullated and nonmedullated fibers. The nerve fibers generally end freely and are slightly branched or unbranched terminations of myelinated and unmyelinated fibers. Moreover, a few nerve fibers end redundant in the form of end-rings, bulb-like, bush-like, club-shaped end end-coil like structures. The complex unencapsulated types of endings are also found in the myocardium of the atrium and the ventricle. The encapsulated endings (Vater-Pacinian; Krause end-bulb) could not be observed.

  5. Comparison between the Correlations of Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography and Visual Field Defects in Standard Automated White-on-White Perimetry versus Pulsar Perimetry.

    Science.gov (United States)

    Alnawaiseh, Maged; Hömberg, Lisann; Eter, Nicole; Prokosch, Verena

    2017-01-01

    To compare the structure-function relationships between retinal nerve fiber layer thickness (RNFLT) and visual field defects measured either by standard automated perimetry (SAP) or by Pulsar perimetry (PP). 263 eyes of 143 patients were prospectively included. Depending on the RNFLT, patients were assigned to the glaucoma group (group A: RNFL score 3-6) or the control group (group B: RNFL score 0-2). Structure-function relationships between RNFLT and mean sensitivity (MS) measured by SAP and PP were analyzed. Throughout the entire group, the MS assessed by PP and SAP correlated significantly with RNFLT in all sectors. In the glaucoma group, there was no significant difference between the correlations RNFL-SAP and RNFL-PP, whereas a significant difference was found in the control group. In the control group, the correlation between structure and function based on the PP data was significantly stronger than that based on SAP.

  6. Functional and structural microanatomy of the fetal sciatic nerve.

    Science.gov (United States)

    Creze, Maud; Zaitouna, Mazen; Krystel, Nyangoh Timoh; Diallo, Djibril; Lebacle, Cédric; Bellin, Marie-France; Ducreux, Denis; Benoit, Gérard; Bessede, Thomas

    2017-10-01

    The ultrastructure of a nerve has implications for surgical nerve repair. The aim of our study was to characterize the fascicular versus fibrillar anatomy and the autonomic versus somatic nature of the fetal sciatic nerve (SN). Immunohistochemistry for vesicular acetylcholine transporter, tyrosine hydroxylase, and peripheral myelin protein 22 was performed to identify cholinergic, adrenergic, and somatic axons, respectively, in the human fetal SN. Two-dimensional (2D) analysis and 3D reconstructions were performed. The fetal SN is composed of one-third stromal tissue and two-thirds neural tissue. Autonomic fibers are predominant over somatic fibers within the neural tissue. The distribution of somatic fibers is initially random, but then become topographically organized after intra- and interfascicular rearrangements have occurred within the nerve. The fetal model presents limitations but enables illustration of the nature of the nerve fibers and the 3D fascicular anatomy of the SN. Muscle Nerve 56: 787-796, 2017. © 2017 Wiley Periodicals, Inc.

  7. Comparison of diagnostic capability of macular ganglion cell complex and retinal nerve fiber layer among primary open angle glaucoma, ocular hypertension, and normal population using Fourier-domain optical coherence tomography and determining their functional correlation in Indian population

    Directory of Open Access Journals (Sweden)

    Nabanita Barua

    2016-01-01

    Full Text Available Context: Analysis of diagnostic ability of macular ganglionic cell complex and retinal nerve fiber layer (RNFL in glaucoma. Aim: To correlate functional and structural parameters and comparing predictive value of each of the structural parameters using Fourier-domain (FD optical coherence tomography (OCT among primary open angle glaucoma (POAG and ocular hypertension (OHT versus normal population. Setting and Design: Single centric, cross-sectional study done in 234 eyes. Materials and Methods: Patients were enrolled in three groups: POAG, ocular hypertensive and normal (40 patients in each group. After comprehensive ophthalmological examination, patients underwent standard automated perimetry and FD-OCT scan in optic nerve head and ganglion cell mode. The relationship was assessed by correlating ganglion cell complex (GCC parameters with mean deviation. Results were compared with RNFL parameters. Statistical Analysis: Data were analyzed with SPSS, analysis of variance, t-test, Pearson′s coefficient, and receiver operating curve. Results: All parameters showed strong correlation with visual field (P 0.5 when compared with other parameters. None of the parameters showed significant diagnostic capability to detect OHT from normal population. In diagnosing early glaucoma from OHT and normal population, only inferior GCC had statistically significant AUC value (0.715. Conclusion: In this study, GCC and RNFL parameters showed equal predictive capability in perimetric versus normal group. In early stage, inferior GCC was the best parameter. In OHT population, single day cross-sectional imaging was not valuable.

  8. Electron microscopic study of the myelinated nerve fibres and the perineurial cell basement membrane in the diabetic human peripheral nerves

    International Nuclear Information System (INIS)

    ElBarrany, Wagih G.; Hamdy, Raid M.; AlHayani, Abdulmonem A.; Jalalah, Sawsan M.

    2009-01-01

    To study the quantitative and ultrastructural changes in myelinated nerve fibers and the basement membranes of the perineurial cells in diabetic nerves. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Saudi Arabia from 2003 to 2005. Human sural nerves were obtained from 15 lower limbs and 5 diabetic nerve biopsies. The total mean and density of myelinated nerve fibers per fascicle were calculated, with density of microtubules and mitochondria in the axoplasm. The number of the perineurial cell basement membrane layers was counted, and thickness of the basement membrane was measured. Among the 15 diabetic and 5 normal human sural nerves, the average diameters, number and surface area of myelinated nerve fibers and axonal microtubules density were found to be less in diabetic nerves. Mitochondrial density was higher in diabetic axons. Thickness of the perineurial cell basement membrane had a greater mean, but the number of perineurial cell layers was less than that of the diabetic group. The inner cellular layer of the perineurium of the diabetic nerves contained large vacuoles containing electron-dense degenerated myelin. A few specimens showed degenerated myelinated nerve fibers, while others showed recovering ones. Retracted axoplasms were encountered with albumin extravasation. Diabetes caused an increase in perineurial permeability. The diabetic sural nerve showed marked decrease in the myelinated nerve fibres, increase degenerated mitochondria, and decreased microtubules. (author)

  9. Reference-Free Assessment of Speech Intelligibility Using Bispectrum of an Auditory Neurogram

    Science.gov (United States)

    Hossain, Mohammad E.; Jassim, Wissam A.; Zilany, Muhammad S. A.

    2016-01-01

    Sensorineural hearing loss occurs due to damage to the inner and outer hair cells of the peripheral auditory system. Hearing loss can cause decreases in audibility, dynamic range, frequency and temporal resolution of the auditory system, and all of these effects are known to affect speech intelligibility. In this study, a new reference-free speech intelligibility metric is proposed using 2-D neurograms constructed from the output of a computational model of the auditory periphery. The responses of the auditory-nerve fibers with a wide range of characteristic frequencies were simulated to construct neurograms. The features of the neurograms were extracted using third-order statistics referred to as bispectrum. The phase coupling of neurogram bispectrum provides a unique insight for the presence (or deficit) of supra-threshold nonlinearities beyond audibility for listeners with normal hearing (or hearing loss). The speech intelligibility scores predicted by the proposed method were compared to the behavioral scores for listeners with normal hearing and hearing loss both in quiet and under noisy background conditions. The results were also compared to the performance of some existing methods. The predicted results showed a good fit with a small error suggesting that the subjective scores can be estimated reliably using the proposed neural-response-based metric. The proposed metric also had a wide dynamic range, and the predicted scores were well-separated as a function of hearing loss. The proposed metric successfully captures the effects of hearing loss and supra-threshold nonlinearities on speech intelligibility. This metric could be applied to evaluate the performance of various speech-processing algorithms designed for hearing aids and cochlear implants. PMID:26967160

  10. Miconazole enhances nerve regeneration and functional recovery after sciatic nerve crush injury.

    Science.gov (United States)

    Lin, Tao; Qiu, Shuai; Yan, Liwei; Zhu, Shuang; Zheng, Canbin; Zhu, Qingtang; Liu, Xiaolin

    2018-05-01

    Improving axonal outgrowth and remyelination is crucial for peripheral nerve regeneration. Miconazole appears to enhance remyelination in the central nervous system. In this study we assess the effect of miconazole on axonal regeneration using a sciatic nerve crush injury model in rats. Fifty Sprague-Dawley rats were divided into control and miconazole groups. Nerve regeneration and myelination were determined using histological and electrophysiological assessment. Evaluation of sensory and motor recovery was performed using the pinprick assay and sciatic functional index. The Cell Counting Kit-8 assay and Western blotting were used to assess the proliferation and neurotrophic expression of RSC 96 Schwann cells. Miconazole promoted axonal regrowth, increased myelinated nerve fibers, improved sensory recovery and walking behavior, enhanced stimulated amplitude and nerve conduction velocity, and elevated proliferation and neurotrophic expression of RSC 96 Schwann cells. Miconazole was beneficial for nerve regeneration and functional recovery after peripheral nerve injury. Muscle Nerve 57: 821-828, 2018. © 2017 Wiley Periodicals, Inc.

  11. Anatomy, Physiology and Function of the Auditory System

    Science.gov (United States)

    Kollmeier, Birger

    The human ear consists of the outer ear (pinna or concha, outer ear canal, tympanic membrane), the middle ear (middle ear cavity with the three ossicles malleus, incus and stapes) and the inner ear (cochlea which is connected to the three semicircular canals by the vestibule, which provides the sense of balance). The cochlea is connected to the brain stem via the eighth brain nerve, i.e. the vestibular cochlear nerve or nervus statoacusticus. Subsequently, the acoustical information is processed by the brain at various levels of the auditory system. An overview about the anatomy of the auditory system is provided by Figure 1.

  12. Ulnar nerve dysfunction

    Science.gov (United States)

    Neuropathy - ulnar nerve; Ulnar nerve palsy; Mononeuropathy; Cubital tunnel syndrome ... Damage to one nerve group, such as the ulnar nerve, is called mononeuropathy . Mononeuropathy means there is damage to a single nerve. Both ...

  13. Radial nerve dysfunction

    Science.gov (United States)

    Neuropathy - radial nerve; Radial nerve palsy; Mononeuropathy ... Damage to one nerve group, such as the radial nerve, is called mononeuropathy . Mononeuropathy means there is damage to a single nerve. Both ...

  14. Bilateral absence of musculocutaneous nerve

    Directory of Open Access Journals (Sweden)

    Mathada V Ravishankar

    2012-01-01

    Full Text Available Brachial plexus is an important group of spinal nerve plexus that supplies the muscles of the upper limb via the ventral rami of the Cervical 5 - Thoracic 1 fibers of the spinal nerves. It is not uncommon to notice the variations during cadaveric dissections in many regions of the body, at different levels, such as, roots, trunks, division, cords, communications, and branches as reported in the literature. Although the nerve supply of the body musculature takes place in the fetal life itself, its course, branching pattern, innervations, and communication can show variable patterns as the fetal development progresses. One such anomaly was noticed during our routine cadaveric dissection in the Department of Anatomy, Jawaharlal Nehru Medical College, Belgaum, showing bilateral absence of the musculocutaneous nerve, which obviously drew the attention of the students of medicine, physiotherapy, and learning clinicians as well.

  15. Low-frequency versus high-frequency synchronisation in chirp-evoked auditory brainstem responses

    DEFF Research Database (Denmark)

    Rønne, Filip Munch; Gøtsche-Rasmussen, Kristian

    2011-01-01

    This study investigates the frequency specific contribution to the auditory brainstem response (ABR) of chirp stimuli. Frequency rising chirps were designed to compensate for the cochlear traveling wave delay, and lead to larger wave-V amplitudes than for click stimuli as more auditory nerve fibr...

  16. Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline

    Science.gov (United States)

    2016-11-28

    Title: Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline Christopher J. Smalt...representation of speech intelligibility in noise. The auditory-periphery model of Zilany et al. (JASA 2009,2014) is used to make predictions of...auditory nerve (AN) responses to speech stimuli under a variety of difficult listening conditions. The resulting cochlear neurogram, a spectrogram

  17. Auditory Perspective Taking

    National Research Council Canada - National Science Library

    Martinson, Eric; Brock, Derek

    2006-01-01

    .... From this knowledge of another's auditory perspective, a conversational partner can then adapt his or her auditory output to overcome a variety of environmental challenges and insure that what is said is intelligible...

  18. Lysine-doped polypyrrole/spider silk protein/poly(l-lactic) acid containing nerve growth factor composite fibers for neural application.

    Science.gov (United States)

    Zhang, Hong; Wang, Kefeng; Xing, Yiming; Yu, Qiaozhen

    2015-11-01

    Lysine-doped polypyrrole (PPy)/regenerated spider silk protein (RSSP)/poly(l-lactic) acid (PLLA)/nerve growth factor (NGF) (L-PRPN) composite scaffold was fabricated by co-axial electrospraying and electrospinning. This L-PRPN composite scaffold had a structure of microfibers with a core-shell structure as the stems and nanofibers as branches. Assessment in vitro demonstrated that the L-PRPN composite micro/nano-fibrous scaffold could maintain integrated structure for at least 4months and the pH value of PBS at about 7.28. It had good biocompatibility and cell adhesion and relatively stable conductivity. PC 12 cells cultured on this scaffold, anisotropic cell-neurite-cell-neurite or neurite-neurite sheets were formed after being cultured for 6days. Evaluations in vivo also showed that L-PRPN composite fibrous conduit was effective at bridging 2.0cm sciatic nerve gap in adult rat within 10months. This conduit and electrical stimulation (ES) through it promoted Schwann cell migration and axonal regrowth. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Correlation between central corneal thickness and visual field defects, cup to disc ratio and retinal nerve fiber layer thickness in primary open angle glaucoma patients.

    Science.gov (United States)

    Sarfraz, Muhammad Haroon; Mehboob, Mohammad Asim; Haq, Rana Intisar Ul

    2017-01-01

    To evaluate the correlation between Central Corneal Thickness (CCT) and Visual Field (VF) defect parameters like Mean Deviation (MD) and Pattern Standard Deviation (PSD), Cup-to-Disc Ratio (CDR) and Retinal Nerve Fibre Layer Thickness (RNFL-T) in Primary Open-Angle Glaucoma (POAG) patients. This cross sectional study was conducted at Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi from September 2015 to September 2016. Sixty eyes of 30 patients with diagnosed POAG were analysed. Correlation of CCT with other variables was studied. Mean age of study population was 43.13±7.54 years. Out of 30 patients, 19 (63.33%) were males and 11 (36.67%) were females. Mean CCT, MD, PSD, CDR and RNFL-T of study population was 528.57±25.47µm, -9.11±3.07, 6.93±2.73, 0.63±0.13 and 77.79±10.44µm respectively. There was significant correlation of CCT with MD, PSD and CDR (r=-0.52, pfield parameters like mean deviation and pattern standard deviation, as well as with cup-to-disc ratio. However, central corneal thickness had no significant relationship with retinal nerve fibre layer thickness.

  20. Imaging the Facial Nerve: A Contemporary Review

    International Nuclear Information System (INIS)

    Gupta, S.; Roehm, P.C.; Mends, F.; Hagiwara, M.; Fatterpekar, G.

    2013-01-01

    Imaging plays a critical role in the evaluation of a number of facial nerve disorders. The facial nerve has a complex anatomical course; thus, a thorough understanding of the course of the facial nerve is essential to localize the sites of pathology. Facial nerve dysfunction can occur from a variety of causes, which can often be identified on imaging. Computed tomography and magnetic resonance imaging are helpful for identifying bony facial canal and soft tissue abnormalities, respectively. Ultrasound of the facial nerve has been used to predict functional outcomes in patients with Bell’s palsy. More recently, diffusion tensor tractography has appeared as a new modality which allows three-dimensional display of facial nerve fibers

  1. Absence of both auditory evoked potentials and auditory percepts dependent on timing cues.

    Science.gov (United States)

    Starr, A; McPherson, D; Patterson, J; Don, M; Luxford, W; Shannon, R; Sininger, Y; Tonakawa, L; Waring, M

    1991-06-01

    An 11-yr-old girl had an absence of sensory components of auditory evoked potentials (brainstem, middle and long-latency) to click and tone burst stimuli that she could clearly hear. Psychoacoustic tests revealed a marked impairment of those auditory perceptions dependent on temporal cues, that is, lateralization of binaural clicks, change of binaural masked threshold with changes in signal phase, binaural beats, detection of paired monaural clicks, monaural detection of a silent gap in a sound, and monaural threshold elevation for short duration tones. In contrast, auditory functions reflecting intensity or frequency discriminations (difference limens) were only minimally impaired. Pure tone audiometry showed a moderate (50 dB) bilateral hearing loss with a disproportionate severe loss of word intelligibility. Those auditory evoked potentials that were preserved included (1) cochlear microphonics reflecting hair cell activity; (2) cortical sustained potentials reflecting processing of slowly changing signals; and (3) long-latency cognitive components (P300, processing negativity) reflecting endogenous auditory cognitive processes. Both the evoked potential and perceptual deficits are attributed to changes in temporal encoding of acoustic signals perhaps occurring at the synapse between hair cell and eighth nerve dendrites. The results from this patient are discussed in relation to previously published cases with absent auditory evoked potentials and preserved hearing.

  2. Sciatic nerve regeneration in rats by a promising electrospun collagen/poly(ε-caprolactone nerve conduit with tailored degradation rate

    Directory of Open Access Journals (Sweden)

    Jiang Xinquan

    2011-07-01

    Full Text Available Abstract Background To cope with the limitations faced by autograft acquisitions particularly for multiple nerve injuries, artificial nerve conduit has been introduced by researchers as a substitute for autologous nerve graft for the easy specification and availability for mass production. In order to best mimic the structures and components of autologous nerve, great efforts have been made to improve the designation of nerve conduits either from materials or fabrication techniques. Electrospinning is an easy and versatile technique that has recently been used to fabricate fibrous tissue-engineered scaffolds which have great similarity to the extracellular matrix on fiber structure. Results In this study we fabricated a collagen/poly(ε-caprolactone (collagen/PCL fibrous scaffold by electrospinning and explored its application as nerve guide substrate or conduit in vitro and in vivo. Material characterizations showed this electrospun composite material which was made of submicron fibers possessed good hydrophilicity and flexibility. In vitro study indicated electrospun collagen/PCL fibrous meshes promoted Schwann cell adhesion, elongation and proliferation. In vivo test showed electrospun collagen/PCL porous nerve conduits successfully supported nerve regeneration through an 8 mm sciatic nerve gap in adult rats, achieving similar electrophysiological and muscle reinnervation results as autografts. Although regenerated nerve fibers were still in a pre-mature stage 4 months postoperatively, the implanted collagen/PCL nerve conduits facilitated more axons regenerating through the conduit lumen and gradually degraded which well matched the nerve regeneration rate. Conclusions All the results demonstrated this collagen/PCL nerve conduit with tailored degradation rate fabricated by electrospinning could be an efficient alternative to autograft for peripheral nerve regeneration research. Due to its advantage of high surface area for cell attachment, it

  3. Neurophysiologic intraoperative monitoring of the vestibulocochlear nerve.

    Science.gov (United States)

    Simon, Mirela V

    2011-12-01

    Neurosurgical procedures involving the skull base and structures within can pose a significant risk of damage to the brain stem and cranial nerves. This can have life-threatening consequences and/or result in devastating neurologic deficits. Over the past decade, intraoperative neurophysiology has significantly evolved and currently offers a great tool for live monitoring of the integrity of nervous structures. Thus, dysfunction can be identified early and prompt modification of the surgical management or operating conditions, leads to avoidance of permanent structural damage.Along these lines, the vestibulocochlear nerve (CN VIII) and, to a greater extent, the auditory pathways as they pass through the brain stem are especially at risk during cerebelopontine angle (CPA), posterior/middle fossa, or brain stem surgery. CN VIII can be damaged by several mechanisms, from vascular compromise to mechanical injury by stretch, compression, dissection, and heat injury. Additionally, cochlea itself can be significantly damaged during temporal bone drilling, by noise, mechanical destruction, or infarction, and because of rupture, occlusion, or vasospasm of the internal auditory artery.CN VIII monitoring can be successfully achieved by live recording of the function of one of its parts, the cochlear or auditory nerve (AN), using the brain stem auditory evoked potentials (BAEPs), electrocochleography (ECochG), and compound nerve action potentials (CNAPs) of the cochlear nerve.This is a review of these techniques, their principle, applications, methodology, interpretation of the evoked responses, and their change from baseline, within the context of surgical and anesthesia environments, and finally the appropriate management of these changes.

  4. Neurotization of the phrenic nerve with accessory nerve for high cervical spinal cord injury with respiratory distress: an anatomic study.

    Science.gov (United States)

    Wang, Ce; Zhang, Ying; Nicholas, Tsai; Wu, Guoxin; Shi, Sheng; Bo, Yin; Wang, Xinwei; Zhou, Xuhui; Yuan, Wen

    2014-01-01

    High cervical spinal cord injury is associated with high morbidity and mortality. Traditional treatments carry various complications such as infection, pacemaker failure and undesirable movement. Thus, a secure surgical strategy with fewer complications analogous to physiological ventilation is still required. We hope to offer one potential method to decrease the complications and improve survival qualities of patients from the aspect of anatomy. The purpose of the study is to provide anatomic details on the accessory nerve and phrenic nerve for neurotization in patients with high spinal cord injuries. 38 cadavers (76 accessory and 76 phrenic nerves) were dissected in the study. The width, length and thickness of each accessory nerve and phrenic nerve above clavicle were measured. The distances from several landmarks on accessory nerve to the origin and the end of the phrenic nerve above clavicle were measured too. Then, the number of motor nerve fibers on different sections of the nerves was calculated using the technique of immunohistochemistry. The accessory nerves distal to its sternocleidomastoid muscular branches were 1.52 ± 0.32 mm ~1.54 ± 0.29 mm in width, 0.52 ± 0.18 mm ~ 0.56 ± 0.20mm in thickness and 9.52 ± 0.98 cm in length. And the phrenic nerves above clavicle were 1.44 ± 0.23 mm ~ 1.45 ± 0.24 mm in width, 0.47 ± 0.15 mm ~ 0.56 ± 0.25 mm in thickness and 6.48 ± 0.78 cm in length. The distance between the starting point of accessory nerve and phrenic nerve were 3.24 ± 1.17 cm, and the distance between the starting point of accessory nerve and the end of the phrenic nerve above clavicle were 8.72 ± 0.84 cm. The numbers of motor nerve fibers in accessory nerve were 1,038 ± 320~1,102 ± 216, before giving out the sternocleidomastoid muscular branches. The number of motor nerve fibers in the phrenic nerve was 911 ± 321~1,338 ± 467. The accessory nerve and the phrenic were similar in width, thickness and the number of motor nerve fibers. And

  5. DIC imaging for identification of motor and sensory nerves

    Directory of Open Access Journals (Sweden)

    Dayu Chen

    2016-09-01

    Full Text Available Identification of motor and sensory nerves is important in applications such as nerve injury repair. Conventional practice relies on time consuming staining methods for this purpose. Here, we use laser scanning infrared differential interference contrast (IR-DIC microscopy for label-free observation of the two types of nerve. Ventral and dorsal nerve roots of adult beagle dogs were collected and sections of different thicknesses were imaged with an IR-DIC microscope. Different texture patterns of the IR-DIC images of the motor and sensory nerve can be distinguished when the section thickness increases to 40μm. This suggests that nerve fibers in motor and sensory nerves have different distribution patterns. The result hints a potential new way for more rapid identification of nerve type in peripheral nerve repair surgery.

  6. Compound sensory action potential in normal and pathological human nerves

    DEFF Research Database (Denmark)

    Krarup, Christian

    2004-01-01

    The compound sensory nerve action potential (SNAP) is the result of phase summation and cancellation of single fiber potentials (SFAPs) with amplitudes that depend on fiber diameter, and the amplitude and shape of the SNAP is determined by the distribution of fiber diameters. Conduction velocitie...... effort and attention to theory and practical detail that may be time consuming....

  7. Optic nerve hypoplasia

    Directory of Open Access Journals (Sweden)

    Savleen Kaur

    2013-01-01

    Full Text Available Optic nerve hypoplasia (ONH is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. With a vast number of cases now being reported, the rarity of ONH is obviously now refuted. The major aspects of ophthalmic evaluation of an infant with possible ONH are visual assessment, fundus examination, and visual electrophysiology. Characteristically, the disc is small, there is a peripapillary double-ring sign, vascular tortuosity, and thinning of the nerve fiber layer. A patient with ONH should be assessed for presence of neurologic, radiologic, and endocrine associations. There may be maternal associations like premature births, fetal alcohol syndrome, maternal diabetes. Systemic associations in the child include endocrine abnormalities, developmental delay, cerebral palsy, and seizures. Besides the hypoplastic optic nerve and chiasm, neuroimaging shows abnormalities in ventricles or white- or gray-matter development, septo-optic dysplasia, hydrocephalus, and corpus callosum abnormalities. There is a greater incidence of clinical neurologic abnormalities in patients with bilateral ONH (65% than patients with unilateral ONH. We present a review on the available literature on the same to urge caution in our clinical practice when dealing with patients with ONH. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, endocrinology consultation with or without genetic testing are helpful in the diagnosis and management of ONH. (Method of search: MEDLINE, PUBMED.

  8. Ultrastructural changes of compressed lumbar ventral nerve roots following decompression

    International Nuclear Information System (INIS)

    El-Barrany, Wagih G.; Hamdy, Raid M.; Al-Hayani, Abdulmonem A.; Jalalah, Sawsan M.; Al-Sayyad, Mohammad J.

    2006-01-01

    To study whether there will be permanent lumbar nerve rot scanning or degeneration secondary to continuous compression followed by decompression on the nerve roots, which can account for postlaminectomy leg weakness or back pain. The study was performed at the Department of Anatomy, Faulty of Medicine, king Abdulaziz University, Jeddah, Kingdom of Saudi Arabia during 2003-2005. Twenty-six adult male New Zealand rabbits were used in the present study. The ventral roots of the left fourth lumbar nerve were clamped for 2 weeks then decompression was allowed by removal of the clips. The left ventral roots of the fourth lumbar nerve were excised for electron microscopic study. One week after nerve root decompression, the ventral root peripheral to the site of compression showed signs of Wallerian degeneration together with signs of regeneration. Schwann cells and myelinated nerve fibers showed severe degenerative changes. Two weeks after decompression, the endoneurium of the ventral root showed extensive edema with an increase in the regenerating myelinated and unmyentilated nerve fibers, and fibroblasts proliferation. Three weeks after decompression, the endoneurium showed an increase in the regenerating myelinated and unmyelinated nerve fibers with diminution of the endoneurial edema, and number of macrophages and an increase in collagen fibrils. Five and 6 weeks after decompression, the endoneurium showed marked diminution of the edema, macrophages, mast cells and fibroblasts. The enoneurium was filed of myelinated and unmyelinated nerve fibers and collagen fibrils. Decompression of the compressed roots of a spinal nerve is followed by regeneration of the nerve fibers and nerve and nerve recovery without endoneurial scarring. (author)

  9. Malformation of the eighth cranial nerve in children.

    Science.gov (United States)

    de Paula-Vernetta, Carlos; Muñoz-Fernández, Noelia; Mas-Estellés, Fernando; Guzmán-Calvete, Abel; Cavallé-Garrido, Laura; Morera-Pérez, Constantino

    2016-01-01

    Prevalence of congenital sensorineural hearing loss (SNHL) is approximately 1.5-6 in every 1,000 newborns. Dysfunction of the auditory nerve (auditory neuropathy) may be involved in up to 1%-10% of cases; hearing losses because of vestibulocochlear nerve (VCN) aplasia are less frequent. The objectives of this study were to describe clinical manifestations, hearing thresholds and aetiology of children with SNHL and VCN aplasia. We present 34 children (mean age 20 months) with auditory nerve malformation and profound HL taken from a sample of 385 children implanted in a 10-year period. We studied demographic characteristics, hearing, genetics, risk factors and associated malformations (Casselman's and Sennaroglu's classifications). Data were processed using a bivariate descriptive statistical analysis (P<.05). Of all the cases, 58.8% were bilateral (IIa/IIa and I/I were the most common). Of the unilateral cases, IIb was the most frequent. Auditory screening showed a sensitivity of 77.4%. A relationship among bilateral cases and systemic pathology was observed. We found a statistically significant difference when comparing hearing loss impairment and patients with different types of aplasia as defined by Casselman's classification. Computed tomography (CT) scan yielded a sensitivity of 46.3% and a specificity of 85.7%. However, magnetic resonance imaging (MRI) was the most sensitive imaging test. Ten percent of the children in a cochlear implant study had aplasia or hypoplasia of the auditory nerve. The degree of auditory loss was directly related to the different types of aplasia (Casselman's classification) Although CT scan and MRI are complementary, the MRI is the test of choice for detecting auditory nerve malformation. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

  10. Beneficial auditory and cognitive effects of auditory brainstem implantation in children.

    Science.gov (United States)

    Colletti, Liliana

    2007-09-01

    This preliminary study demonstrates the development of hearing ability and shows that there is a significant improvement in some cognitive parameters related to selective visual/spatial attention and to fluid or multisensory reasoning, in children fitted with auditory brainstem implantation (ABI). The improvement in cognitive paramenters is due to several factors, among which there is certainly, as demonstrated in the literature on a cochlear implants (CIs), the activation of the auditory sensory canal, which was previously absent. The findings of the present study indicate that children with cochlear or cochlear nerve abnormalities with associated cognitive deficits should not be excluded from ABI implantation. The indications for ABI have been extended over the last 10 years to adults with non-tumoral (NT) cochlear or cochlear nerve abnormalities that cannot benefit from CI. We demonstrated that the ABI with surface electrodes may provide sufficient stimulation of the central auditory system in adults for open set speech recognition. These favourable results motivated us to extend ABI indications to children with profound hearing loss who were not candidates for a CI. This study investigated the performances of young deaf children undergoing ABI, in terms of their auditory perceptual development and their non-verbal cognitive abilities. In our department from 2000 to 2006, 24 children aged 14 months to 16 years received an ABI for different tumour and non-tumour diseases. Two children had NF2 tumours. Eighteen children had bilateral cochlear nerve aplasia. In this group, nine children had associated cochlear malformations, two had unilateral facial nerve agenesia and two had combined microtia, aural atresia and middle ear malformations. Four of these children had previously been fitted elsewhere with a CI with no auditory results. One child had bilateral incomplete cochlear partition (type II); one child, who had previously been fitted unsuccessfully elsewhere

  11. Anatomical feasibility of vagus nerve esophageal branch transfer to the phrenic nerve☆

    Science.gov (United States)

    Wang, Ce; Liu, Jun; Yuan, Wen; Zhou, Xuhui; Wang, Xinwei; Xu, Peng; Chen, Jian; Wu, Guoxin; Shi, Sheng

    2012-01-01

    This study measured the vagus and phrenic nerves from 12 adult cadavers. We found that the width and thickness of the vagus and phrenic nerves were different in the chest. The distance from the point of the vagus nerve and phrenic nerve on the plane of the inferior border of portal pulmonary arteries (T point) was approximately 7 cm to the diaphragm and was approximately 10 cm to the clavicle level. The number of motor fibers in the vagus nerves was 1 716 ± 362, and the number of nerve fibers was 4 473 ± 653. The number of motor fibers in the phrenic nerves ranged from 3 078 ± 684 to 4 794 ± 638, and the number of nerve fibers ranged from 3 437 ± 642 to 5 071 ± 723. No significant difference was found in the total number of nerve fibers. The results suggest that width, thickness, and total number of nerve fibers are similar between the vagus and phrenic nerves, but the number of motor fibers is different between them. PMID:25745467

  12. Cortical Representations of Speech in a Multitalker Auditory Scene.

    Science.gov (United States)

    Puvvada, Krishna C; Simon, Jonathan Z

    2017-09-20

    The ability to parse a complex auditory scene into perceptual objects is facilitated by a hierarchical auditory system. Successive stages in the hierarchy transform an auditory scene of multiple overlapping sources, from peripheral tonotopically based representations in the auditory nerve, into perceptually distinct auditory-object-based representations in the auditory cortex. Here, using magnetoencephalography recordings from men and women, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in distinct hierarchical stages of the auditory cortex. Using systems-theoretic methods of stimulus reconstruction, we show that the primary-like areas in the auditory cortex contain dominantly spectrotemporal-based representations of the entire auditory scene. Here, both attended and ignored speech streams are represented with almost equal fidelity, and a global representation of the full auditory scene with all its streams is a better candidate neural representation than that of individual streams being represented separately. We also show that higher-order auditory cortical areas, by contrast, represent the attended stream separately and with significantly higher fidelity than unattended streams. Furthermore, the unattended background streams are more faithfully represented as a single unsegregated background object rather than as separated objects. Together, these findings demonstrate the progression of the representations and processing of a complex acoustic scene up through the hierarchy of the human auditory cortex. SIGNIFICANCE STATEMENT Using magnetoencephalography recordings from human listeners in a simulated cocktail party environment, we investigate how a complex acoustic scene consisting of multiple speech sources is represented in separate hierarchical stages of the auditory cortex. We show that the primary-like areas in the auditory cortex use a dominantly spectrotemporal-based representation of the entire auditory

  13. Binaural processing by the gecko auditory periphery.

    Science.gov (United States)

    Christensen-Dalsgaard, Jakob; Tang, Yezhong; Carr, Catherine E

    2011-05-01

    Lizards have highly directional ears, owing to strong acoustical coupling of the eardrums and almost perfect sound transmission from the contralateral ear. To investigate the neural processing of this remarkable tympanic directionality, we combined biophysical measurements of eardrum motion in the Tokay gecko with neurophysiological recordings from the auditory nerve. Laser vibrometry shows that their ear is a two-input system with approximately unity interaural transmission gain at the peak frequency (∼ 1.6 kHz). Median interaural delays are 260 μs, almost three times larger than predicted from gecko head size, suggesting interaural transmission may be boosted by resonances in the large, open mouth cavity (Vossen et al. 2010). Auditory nerve recordings are sensitive to both interaural time differences (ITD) and interaural level differences (ILD), reflecting the acoustical interactions of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200-500 μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons in the auditory pathway should be directional.

  14. Structure-function relationship between the octopus perimeter cluster mean sensitivity and sector retinal nerve fiber layer thickness measured with the RTVue optical coherence tomography and scanning laser polarimetry.

    Science.gov (United States)

    Naghizadeh, Farzaneh; Garas, Anita; Vargha, Péter; Holló, Gábor

    2014-01-01

    To determine structure-function relationship between each of 16 Octopus perimeter G2 program clusters and the corresponding 16 peripapillary sector retinal nerve fiber layer thickness (RNFLT) values measured with the RTVue-100 Fourier-domain optical coherence tomography (RTVue OCT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) and enhanced corneal compensation (GDx-ECC) corneal compensation. One eye of 110 white patients (15 healthy, 20 ocular hypertensive, and 75 glaucoma eyes) were investigated. The Akaike information criterion and the F test were used to identify the best fitting model. Parabolic relationship with logarithmic cluster mean sensitivity and linear sector RNFLT values provided the best fit. For RTVue OCT, significant (P0.05) was found for the control eyes. Mean sensitivity of the Octopus visual field clusters showed significant parabolic relationship with the corresponding peripapillary RNFLT sectors. The relationship was more general with the RTVue OCT than GDx-VCC or GDx-ECC. The results show that visual field clusters of the Octopus G program can be applied for detailed structure-function research.

  15. From ‘Nerve Fiber Regeneration’ to ‘Functional Changes’ in the Human Brain – On the Paradigm-Shifting Work of the Experimental Physiologist Albrecht Bethe (1872-1954 in Frankfurt am Main

    Directory of Open Access Journals (Sweden)

    Frank W Stahnisch

    2016-02-01

    Full Text Available Until the beginning 1930s the traditional dogma that the human central nervous system did not possess any abilities to adapt functionally to degenerative processes and external injuries loomed large in the field of the brain sciences (Hirnforschung. Cutting-edge neuroanatomists, such as the luminary Wilhelm Waldeyer (1836–1921 in Germany or the Nobel Prize laureate Santiago Ramón y Cajal (1852–1934 in Spain, debated any regenerative and thus plastic properties in the human brain. A renewed interest arose in the scientific community to investigate the pathologies and the healing processes in the human central nervous system after the return of the high number of brain injured war veterans from the fronts during and after the First World War (1914–1918. A leading research center in this area was the Institute for the Scientific Study of the Effects of Brain Injuries, which the neurologist Ludwig Edinger (1855–1918 had founded shortly before the war. This article specifically deals with the physiological research on nerve fiber plasticity by Albrecht Bethe (1872–1954 at the respective institute of the University of Frankfurt am Main. Bethe conducted here his paradigmatic experimental studies on the pathophysiological and clinical phenomena of peripheral and central nervous system regeneration.

  16. Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres: multiple amplification of axonal regeneration

    OpenAIRE

    Yu-hui Kou; Pei-xun Zhang; Yan-hua Wang; Bo Chen; Na Han; Feng Xue; Hong-bo Zhang; Xiao-feng Yin; Bao-guo Jiang

    2015-01-01

    Multiple-bud regeneration, i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve fiber regeneration. Our previous studies have verified the limit and validity of multiple amplification of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple amplification of myelinated ne...

  17. Attending to auditory memory.

    Science.gov (United States)

    Zimmermann, Jacqueline F; Moscovitch, Morris; Alain, Claude

    2016-06-01

    Attention to memory describes the process of attending to memory traces when the object is no longer present. It has been studied primarily for representations of visual stimuli with only few studies examining attention to sound object representations in short-term memory. Here, we review the interplay of attention and auditory memory with an emphasis on 1) attending to auditory memory in the absence of related external stimuli (i.e., reflective attention) and 2) effects of existing memory on guiding attention. Attention to auditory memory is discussed in the context of change deafness, and we argue that failures to detect changes in our auditory environments are most likely the result of a faulty comparison system of incoming and stored information. Also, objects are the primary building blocks of auditory attention, but attention can also be directed to individual features (e.g., pitch). We review short-term and long-term memory guided modulation of attention based on characteristic features, location, and/or semantic properties of auditory objects, and propose that auditory attention to memory pathways emerge after sensory memory. A neural model for auditory attention to memory is developed, which comprises two separate pathways in the parietal cortex, one involved in attention to higher-order features and the other involved in attention to sensory information. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Ulnar nerve sonography in leprosy neuropathy.

    Science.gov (United States)

    Wang, Zhu; Liu, Da-Yue; Lei, Yang-Yang; Yang, Zheng; Wang, Wei

    2016-01-01

    A 23-year-old woman presented with a half-year history of right forearm sensory and motor dysfunction. Ultrasound imaging revealed definite thickening of the right ulnar nerve trunk and inner epineurium, along with heterogeneous hypoechogenicity and unclear nerve fiber bundle. Color Doppler exhibited a rich blood supply, which was clearly different from the normal ulnar nerve presentation with a scarce blood supply. The patient subsequently underwent needle aspiration of the right ulnar nerve, and histopathological examination confirmed that granulomatous nodules had formed with a large number of infiltrating lymphocytes and a plurality of epithelioid cells in the fibrous connective tissues, with visible atypical foam cells and proliferous vascularization, consistent with leprosy. Our report will familiarize readers with the characteristic sonographic features of the ulnar nerve in leprosy, particularly because of the decreasing incidence of leprosy in recent years.

  19. Auditory Processing Disorder (For Parents)

    Science.gov (United States)

    ... role. Auditory cohesion problems: This is when higher-level listening tasks are difficult. Auditory cohesion skills — drawing inferences from conversations, understanding riddles, or comprehending verbal math problems — require heightened auditory processing and language levels. ...

  20. Fiber Sensor Technology Today

    Science.gov (United States)

    Hotate, Kazuo

    2006-08-01

    Fiber sensor technologies are overviewed. Since the early 1970s, this field has been developed, on the basis of the same devices and photonic principles as fiber communication technologies. Besides simple configurations, in which the fiber acts only as a data transmission line, sophisticated configurations have also been developed, in which the fiber is used as a device to realize unique sensing mechanisms. The fiber optic gyroscope (FOG) is a good example, and has been developed as an absolute rotation sensor used, for example, for navigation and/or attitude control applications. Compared with traditional spinning-mass gyroscopes, the FOG has advantages, such as a short warming-up time, a light weight, and easy handling. A Japanese satellite, which was launched in August 2005 with a mission to observe the aurora, is controlled with a FOG. The FOG has also been used in consumer applications, such as the camera stabilizer, radio-controlled (RC) helicopter navigation, and the control of humanoid robots. Recently, distributed and multiplexed sensing schemes, in particular, have been studied and developed, in which a long fiber acts like a “nerve” for feeling the strain and/or the temperature distribution along the fiber. Performances of artificial nerve systems have markedly improved within the last couple of years, in spatial resolution and measurement speed. By embedding the “fiber-optic nerve system” in aircraft wings, bridges and tall buildings, these materials and structures can sense damage to prevent disasters.

  1. Clinical applied value of brain stem auditory evoked potential in facial neuritis patients combined the damage of other cranial nerves%伴其他颅神经症状的面神经炎患者治疗前后的脑干听觉诱发电位研究

    Institute of Scientific and Technical Information of China (English)

    王金风; 王民

    2012-01-01

    Objective: To explore the clinical applied value of brain stem auditoryk evoed potential (BAEP)in facial neuritis patients combined with damage of other cranial nerves. Methods: Fifty facial neuritis patients combined with damage of other cranial nerves were selected to get BAEP information) the results before and after treatment were analyzed. Results;The inter-peak latencies (IPL) of Ⅰ -- Ⅲ, Ⅲ - V . Ⅰ - V were significantly shorten(P<0. 01)after treatment of the. More than one IPL shortened IPL took up 84%. 74% cases had prolonged potential latencies (PL) of Wave I , Ⅲ and V with more than one shortened or disappeared waveform. In 69 % cases with amplitude of wave V increased and ratio of V/ I more than 0. 5 or ILD of bilateral Wave V was less than 0. 3 ms, IPL of Ⅲ - V shorter than that of Ⅰ - Ⅲ. Conclusion:Facial neuritis involves not only medial surface nerves of foramen stylomastoi-deum but also brainstem and/or other cranial nerves . BAEP can objectively reflect the function of audi-tory system and brain stem, and can be used to follow-up with patients with facial neuritis.%目的:观察伴其他颅神经症状的面神经炎患者治疗前后的脑干听觉诱发电位(BAEP)表现.方法:选择50例面神经炎伴其他颅神经症状的患者进行BAEP检测,并进行治疗前后对比.结果:与治疗前相比,治疗后Ⅱ-Ⅲ、Ⅲ-Ⅴ、Ⅰ-Ⅴ波IPL明显缩短(P<0.01),其中有一个以上的IPL缩短者42例占84%;Ⅰ、Ⅲ、Ⅴ波PL有一个以上缩短或治疗前BAEP波形消失而于治疗后出现者37例占74%;Ⅴ波波幅增高并且Ⅴ/Ⅰ IPL比大于0.5或双侧Ⅴ波侧间潜伏期差(IDL)小于0.3 ms,Ⅲ-Ⅴ波IPL小于Ⅰ-Ⅲ波IPL的35例占70%.结论:面神经炎不仅累及茎乳孔内面神经,还可累及脑干和其他颅神经.BAEP可以客观地反映面神经炎患者听觉系统和脑干功能,因此可以用于对该类患者进行疗效观察.

  2. Transfer of obturator nerve for femoral nerve injury: an experiment study in rats.

    Science.gov (United States)

    Meng, Depeng; Zhou, Jun; Lin, Yaofa; Xie, Zheng; Chen, Huihao; Yu, Ronghua; Lin, Haodong; Hou, Chunlin

    2018-07-01

    Quadriceps palsy is mainly caused by proximal lesions in the femoral nerve. The obturator nerve has been previously used to repair the femoral nerve, although only a few reports have described the procedure, and the outcomes have varied. In the present study, we aimed to confirm the feasibility and effectiveness of this treatment in a rodent model using the randomized control method. Sixty Sprague-Dawley rats were randomized into two groups: the experimental group, wherein rats underwent femoral neurectomy and obturator nerve transfer to the femoral nerve motor branch; and the control group, wherein rats underwent femoral neurectomy without nerve transfer. Functional outcomes were measured using the BBB score, muscle mass, and histological assessment. At 12 and 16 weeks postoperatively, the rats in the experimental group exhibited recovery to a stronger stretch force of the knee and higher BBB score, as compared to the control group (p nerve with myelinated and unmyelinated fibers was observed in the experimental group. No significant differences were observed between groups at 8 weeks postoperatively (p > 0.05). Obturator nerve transfer for repairing femoral nerve injury was feasible and effective in a rat model, and can hence be considered as an option for the treatment of femoral nerve injury.

  3. Effect of Surface Pore Structure of Nerve Guide Conduit on Peripheral Nerve Regeneration

    Science.gov (United States)

    Oh, Se Heang; Kim, Jin Rae; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang

    2013-01-01

    Polycaprolactone (PCL)/Pluronic F127 nerve guide conduits (NGCs) with different surface pore structures (nano-porous inner surface vs. micro-porous inner surface) but similar physical and chemical properties were fabricated by rolling the opposite side of asymmetrically porous PCL/F127 membranes. The effect of the pore structure on peripheral nerve regeneration through the NGCs was investigated using a sciatic nerve defect model of rats. The nerve fibers and tissues were shown to have regenerated along the longitudinal direction through the NGC with a nano-porous inner surface (Nanopore NGC), while they grew toward the porous wall of the NGC with a micro-porous inner surface (Micropore NGC) and, thus, their growth was restricted when compared with the Nanopore NGC, as investigated by immunohistochemical evaluations (by fluorescence microscopy with anti-neurofilament staining and Hoechst staining for growth pattern of nerve fibers), histological evaluations (by light microscopy with Meyer's modified trichrome staining and Toluidine blue staining and transmission electron microscopy for the regeneration of axon and myelin sheath), and FluoroGold retrograde tracing (for reconnection between proximal and distal stumps). The effect of nerve growth factor (NGF) immobilized on the pore surfaces of the NGCs on nerve regeneration was not so significant when compared with NGCs not containing immobilized NGF. The NGC system with different surface pore structures but the same chemical/physical properties seems to be a good tool that is used for elucidating the surface pore effect of NGCs on nerve regeneration. PMID:22871377

  4. [Glaucoma and optic nerve drusen: Limitations of optic nerve head OCT].

    Science.gov (United States)

    Poli, M; Colange, J; Goutagny, B; Sellem, E

    2017-09-01

    Optic nerve head drusen are congenital calcium deposits located in the prelaminar section of the optic nerve head. Their association with visual field defects has been classically described, but the diagnosis of glaucoma is not easy in these cases of altered optic nerve head anatomy. We describe the case of a 67-year-old man with optic nerve head drusen complicated by glaucoma, which was confirmed by visual field and OCT examination of the peripapillary retinal nerve fiber layer (RNFL), but the measurement of the minimum distance between the Bruch membrane opening and the internal limiting membrane (minimum rim width, BMO-MRW) by OCT was normal. OCT of the BMO-MRW is a new diagnostic tool for glaucoma. Superficial optic nerve head drusen, which are found between the internal limiting membrane and the Bruch's membrane opening, overestimate the value of this parameter. BMO-MRW measurement is not adapted to cases of optic nerve head drusen and can cause false-negative results for this parameter, and the diagnosis of glaucoma in this case should be based on other parameters such as the presence of a fascicular defect in the retinal nerve fibers, RNFL or macular ganglion cell complex thinning, as well as visual field data. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Representation of acoustic signals in the eighth nerve of the Tokay gecko. II. Masking of pure tones with noise.

    Science.gov (United States)

    Sams-Dodd, F; Capranica, R R

    1996-10-01

    Acoustic signals are generally encoded in the peripheral auditory system of vertebrates by a duality scheme. For frequency components that fall within the excitatory tuning curve, individual eighth nerve fibers can encode the effective spectral energy by a spike-rate code, while simultaneously preserving the signal waveform periodicity of lower frequency components by phase-locked spike-train discharges. To explore how robust this duality of representation may be in the presence of noise, we recorded the responses of auditory fibers in the eighth nerve of the Tokay gecko to tonal stimuli when masking noise was added simultaneously. We found that their spike-rate functions reached plateau levels fairly rapidly in the presence of noise, so the ability to signal the presence of a tone by a concomitant change in firing rate was quickly lost. On the other hand, their synchronization functions maintained a high degree of phase-locked firings to the tone even in the presence of high-intensity masking noise, thus enabling a robust detection of the tonal signal. Critical ratios (CR) and critical bandwidths showed that in the frequency range where units are able to phaselock to the tonal periodicity, the CR bands were relatively narrow and the bandwidths were independent of noise level. However, to higher frequency tones where phaselocking fails and only spike-rate codes apply, the CR bands were much wider and depended upon noise level, so that their ability to filter tones out of a noisy background degraded with increasing noise levels. The greater robustness of phase-locked temporal encoding contrasted with spike-rate coding verifies a important advantage in using lower frequency signals for communication in noisy environments.

  6. Evaluation of Morphological and Functional Nerve Recovery of Rat Sciatic Nerve with a Hyaff11-Based Nerve Guide

    Directory of Open Access Journals (Sweden)

    K. Jansen

    2006-01-01

    Full Text Available Application of a Hyaff11-based nerve guide was studied in rats. Functional tests were performed to study motor nerve recovery. A withdrawal reflex test was performed to test sensory recovery. Morphology was studied by means of histology on explanted tissue samples. Motor nerve recovery was established within 7 weeks. Hereafter, some behavioral parameters like alternating steps showed an increase in occurence, while others remained stable. Sensory function was observed within the 7 weeks time frame. Nerve tissue had bridged the 10-mm gap within 7 weeks. The average nerve fiber surface area increased significantly in time. In situ degradation of the nerve conduit was fully going on at week 7 and tubes had collapsed by then. At weeks 15 and 21, the knitted tube wall structure was completely surrounded by macrophages and giant cells, and matrix was penetrating the tube wall. We conclude that a Hyaff11-based nerve guide can be used to bridge short peripheral nerve defects in rat. However, adaptations need to be made.

  7. A mathematical model for describing the retinal nerve fiber bundle trajectories in the human eye: average course, variability, and influence of refraction, optic disc size and optic disc position.

    Science.gov (United States)

    Jansonius, Nomdo M; Schiefer, Julia; Nevalainen, Jukka; Paetzold, Jens; Schiefer, Ulrich

    2012-12-01

    Previously we developed a mathematical model for describing the retinal nerve fiber bundle trajectories in the superior-temporal and inferior-temporal regions of the human retina, based on traced trajectories extracted from fundus photographs. Aims of the current study were to (i) validate the existing model, (ii) expand the model to the entire retina and (iii) determine the influence of refraction, optic disc size and optic disc position on the trajectories. A new set of fundus photographs was collected comprising 28 eyes of 28 subjects. From these 28 photographs, 625 trajectories were extracted. Trajectories in the temporal region of the retina were compared to the existing model. In this region, 347 of 399 trajectories (87%) were within the 95% central range of the existing model. The model was extended to the nasal region. With this extension, the model can now be applied to the entire retina that corresponds to the visual field as tested with standard automated perimetry (up to approximately 30° eccentricity). There was an asymmetry between the superior and inferior hemifields and a considerable location-specific inter-subject variability. In the nasal region, we found two "singularities", located roughly at the one and five o'clock positions for the right optic disc. Here, trajectories from relatively widespread areas of the retina converge. Associations between individual deviations from the model and refraction, optic disc size and optic disc position were studied with multiple linear regression. Refraction (P = 0.021) and possibly optic disc inclination (P = 0.09) influenced the trajectories in the superior-temporal region. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Recovery of the sub-basal nerve plexus and superficial nerve terminals after corneal epithelial injury in mice.

    Science.gov (United States)

    Downie, Laura E; Naranjo Golborne, Cecilia; Chen, Merry; Ho, Ngoc; Hoac, Cam; Liyanapathirana, Dasun; Luo, Carol; Wu, Ruo Bing; Chinnery, Holly R

    2018-06-01

    Our aim was to compare regeneration of the sub-basal nerve plexus (SBNP) and superficial nerve terminals (SNT) following corneal epithelial injury. We also sought to compare agreement when quantifying nerve parameters using different image analysis techniques. Anesthetized, female C57BL/6 mice received central 1-mm corneal epithelial abrasions. Four-weeks post-injury, eyes were enucleated and processed for PGP9.5 to visualize the corneal nerves using wholemount immunofluorescence staining and confocal microscopy. The percentage area of the SBNP and SNT were quantified using: ImageJ automated thresholds, ImageJ manual thresholds and manual tracings in NeuronJ. Nerve sum length was quantified using NeuronJ and Imaris. Agreement between methods was considered with Bland-Altman analyses. Four-weeks post-injury, the sum length of nerve fibers in the SBNP, but not the SNT, was reduced compared with naïve eyes. In the periphery, but not central cornea, of both naïve and injured eyes, nerve fiber lengths in the SBNP and SNT were strongly correlated. For quantifying SBNP nerve axon area, all image analysis methods were highly correlated. In the SNT, there was poor correlation between manual methods and auto-thresholding, with a trend towards underestimating nerve fiber area using auto-thresholding when higher proportions of nerve fibers were present. In conclusion, four weeks after superficial corneal injury, there is differential recovery of epithelial nerve axons; SBNP sum length is reduced, however the sum length of SNTs is similar to naïve eyes. Care should be taken when selecting image analysis methods to compare nerve parameters in different depths of the corneal epithelium due to differences in background autofluorescence. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Compound sensory action potential in normal and pathological human nerves

    DEFF Research Database (Denmark)

    Krarup, Christian

    2004-01-01

    The compound sensory nerve action potential (SNAP) is the result of phase summation and cancellation of single fiber potentials (SFAPs) with amplitudes that depend on fiber diameter, and the amplitude and shape of the SNAP is determined by the distribution of fiber diameters. Conduction velocities...... dispersion over increasing conduction distance is greater for the SNAP than CMAP, and demonstration of conduction block is therefore difficult. In addition, the effect of temporal dispersion on amplitude and shape is strongly dependent on the number of conducting fibers and their distribution, and......, with fiber loss or increased conduction velocity variability changes of the SNAP may be smaller than expected from normal nerve. The biophysical characteristics of sensory and motor fibers differ, and this may to some extent determine divergent pathophysiological changes in sensory and motor fibers...

  10. Auditory-motor learning influences auditory memory for music.

    Science.gov (United States)

    Brown, Rachel M; Palmer, Caroline

    2012-05-01

    In two experiments, we investigated how auditory-motor learning influences performers' memory for music. Skilled pianists learned novel melodies in four conditions: auditory only (listening), motor only (performing without sound), strongly coupled auditory-motor (normal performance), and weakly coupled auditory-motor (performing along with auditory recordings). Pianists' recognition of the learned melodies was better following auditory-only or auditory-motor (weakly coupled and strongly coupled) learning than following motor-only learning, and better following strongly coupled auditory-motor learning than following auditory-only learning. Auditory and motor imagery abilities modulated the learning effects: Pianists with high auditory imagery scores had better recognition following motor-only learning, suggesting that auditory imagery compensated for missing auditory feedback at the learning stage. Experiment 2 replicated the findings of Experiment 1 with melodies that contained greater variation in acoustic features. Melodies that were slower and less variable in tempo and intensity were remembered better following weakly coupled auditory-motor learning. These findings suggest that motor learning can aid performers' auditory recognition of music beyond auditory learning alone, and that motor learning is influenced by individual abilities in mental imagery and by variation in acoustic features.

  11. Engineering a multimodal nerve conduit for repair of injured peripheral nerve

    Science.gov (United States)

    Quigley, A. F.; Bulluss, K. J.; Kyratzis, I. L. B.; Gilmore, K.; Mysore, T.; Schirmer, K. S. U.; Kennedy, E. L.; O'Shea, M.; Truong, Y. B.; Edwards, S. L.; Peeters, G.; Herwig, P.; Razal, J. M.; Campbell, T. E.; Lowes, K. N.; Higgins, M. J.; Moulton, S. E.; Murphy, M. A.; Cook, M. J.; Clark, G. M.; Wallace, G. G.; Kapsa, R. M. I.

    2013-02-01

    Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate

  12. Magnetic resonance imaging of facial nerve schwannoma.

    Science.gov (United States)

    Thompson, Andrew L; Aviv, Richard I; Chen, Joseph M; Nedzelski, Julian M; Yuen, Heng-Wai; Fox, Allan J; Bharatha, Aditya; Bartlett, Eric S; Symons, Sean P

    2009-12-01

    This study characterizes the magnetic resonance (MR) appearances of facial nerve schwannoma (FNS). We hypothesize that the extent of FNS demonstrated on MR will be greater compared to prior computed tomography studies, that geniculate involvement will be most common, and that cerebellar pontine angle (CPA) and internal auditory canal (IAC) involvement will more frequently result in sensorineural hearing loss (SNHL). Retrospective study. Clinical, pathologic, and enhanced MR imaging records of 30 patients with FNS were analyzed. Morphologic characteristics and extent of segmental facial nerve involvement were documented. Median age at initial imaging was 51 years (range, 28-76 years). Pathologic confirmation was obtained in 14 patients (47%), and the diagnosis reached in the remainder by identification of a mass, thickening, and enhancement along the course of the facial nerve. All 30 lesions involved two or more contiguous segments of the facial nerve, with 28 (93%) involving three or more segments. The median segments involved per lesion was 4, mean of 3.83. Geniculate involvement was most common, in 29 patients (97%). CPA (P = .001) and IAC (P = .02) involvement was significantly related to SNHL. Seventeen patients (57%) presented with facial nerve dysfunction, manifesting in 12 patients as facial nerve weakness or paralysis, and/or in eight with involuntary movements of the facial musculature. This study highlights the morphologic heterogeneity and typical multisegment involvement of FNS. Enhanced MR is the imaging modality of choice for FNS. The neuroradiologist must accurately diagnose and characterize this lesion, and thus facilitate optimal preoperative planning and counseling.

  13. Femoral nerve damage (image)

    Science.gov (United States)

    The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

  14. Ulnar nerve damage (image)

    Science.gov (United States)

    The ulnar nerve originates from the brachial plexus and travels down arm. The nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where ...

  15. Functional and Physical Outcomes following Use of a Flexible CO2 Laser Fiber and Bipolar Electrocautery in Close Proximity to the Rat Sciatic Nerve with Correlation to an In Vitro Thermal Profile Model

    Directory of Open Access Journals (Sweden)

    A. M. Robinson

    2015-01-01

    Full Text Available This study compared functional and physical collateral damage to a nerve when operating a Codman MALIS Bipolar Electrosurgical System CMC-III or a CO2 laser coupled to a laser, with correlation to an in vitro model of heating profiles created by the devices in thermochromic ink agarose. Functional damage of the rat sciatic nerve after operating the MALIS or CO2 laser at various power settings and proximities to the nerve was measured by electrically evoked nerve action potentials, and histology of the nerve was used to assess physical damage. Thermochromic ink dissolved in agarose was used to model the spatial and temporal profile of the collateral heating zone of the electrosurgical system and the laser ablation cone. We found that this laser can be operated at 2 W directly above the nerve with minimal damage, while power settings of 5 W and 10 W resulted in acute functional and physical nerve damage, correlating with the maximal heating cone in the thermochromic ink model. MALIS settings up to 40 (11 W did not result in major functional or physical nerve damage until the nerve was between the forceps tips, correlating with the hottest zone, localized discretely between the tips.

  16. Effect of age at cochlear implantation on auditory and speech development of children with auditory neuropathy spectrum disorder.

    Science.gov (United States)

    Liu, Yuying; Dong, Ruijuan; Li, Yuling; Xu, Tianqiu; Li, Yongxin; Chen, Xueqing; Gong, Shusheng

    2014-12-01

    To evaluate the auditory and speech abilities in children with auditory neuropathy spectrum disorder (ANSD) after cochlear implantation (CI) and determine the role of age at implantation. Ten children participated in this retrospective case series study. All children had evidence of ANSD. All subjects had no cochlear nerve deficiency on magnetic resonance imaging and had used the cochlear implants for a period of 12-84 months. We divided our children into two groups: children who underwent implantation before 24 months of age and children who underwent implantation after 24 months of age. Their auditory and speech abilities were evaluated using the following: behavioral audiometry, the Categories of Auditory Performance (CAP), the Meaningful Auditory Integration Scale (MAIS), the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), the Standard-Chinese version of the Monosyllabic Lexical Neighborhood Test (LNT), the Multisyllabic Lexical Neighborhood Test (MLNT), the Speech Intelligibility Rating (SIR) and the Meaningful Use of Speech Scale (MUSS). All children showed progress in their auditory and language abilities. The 4-frequency average hearing level (HL) (500Hz, 1000Hz, 2000Hz and 4000Hz) of aided hearing thresholds ranged from 17.5 to 57.5dB HL. All children developed time-related auditory perception and speech skills. Scores of children with ANSD who received cochlear implants before 24 months tended to be better than those of children who received cochlear implants after 24 months. Seven children completed the Mandarin Lexical Neighborhood Test. Approximately half of the children showed improved open-set speech recognition. Cochlear implantation is helpful for children with ANSD and may be a good optional treatment for many ANSD children. In addition, children with ANSD fitted with cochlear implants before 24 months tended to acquire auditory and speech skills better than children fitted with cochlear implants after 24 months. Copyright © 2014

  17. Auditory Integration Training

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2002-07-01

    Full Text Available Auditory integration training (AIT is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depressin, and hyperacute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of The Sound of a Moracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

  18. Review: Auditory Integration Training

    Directory of Open Access Journals (Sweden)

    Zahra Ja'fari

    2003-01-01

    Full Text Available Auditory integration training (AIT is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depression, and hyper acute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of the sound of a miracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

  19. Transdermal optogenetic peripheral nerve stimulation

    Science.gov (United States)

    Maimon, Benjamin E.; Zorzos, Anthony N.; Bendell, Rhys; Harding, Alexander; Fahmi, Mina; Srinivasan, Shriya; Calvaresi, Peter; Herr, Hugh M.

    2017-06-01

    Objective: A fundamental limitation in both the scientific utility and clinical translation of peripheral nerve optogenetic technologies is the optical inaccessibility of the target nerve due to the significant scattering and absorption of light in biological tissues. To date, illuminating deep nerve targets has required implantable optical sources, including fiber-optic and LED-based systems, both of which have significant drawbacks. Approach: Here we report an alternative approach involving transdermal illumination. Utilizing an intramuscular injection of ultra-high concentration AAV6-hSyn-ChR2-EYFP in rats. Main results: We demonstrate transdermal stimulation of motor nerves at 4.4 mm and 1.9 mm depth with an incident laser power of 160 mW and 10 mW, respectively. Furthermore, we employ this technique to accurately control ankle position by modulating laser power or position on the skin surface. Significance: These results have the potential to enable future scientific optogenetic studies of pathologies implicated in the peripheral nervous system for awake, freely-moving animals, as well as a basis for future clinical studies.

  20. Simulation of multipolar fiber selective neural stimulation using intrafascicular electrodes

    NARCIS (Netherlands)

    Meier, J.H.; Meier, Jan H.; Rutten, Wim; Zoutman, Arne E.; Boom, H.B.K.; Bergveld, Piet

    1992-01-01

    A realistic, quantitative model for the excitation of myelinated nerve fibers by intrafascicular electrodes is presented. It predicts the stimulatory regions of any configuration of any number of electrodes, positioned anywhere inside the fascicle. The model has two parts. First, the nerve fiber is

  1. Chemoattractive capacity of different lengths of nerve fragments bridging regeneration chambers for the repair of sciatic nerve defects

    Institute of Scientific and Technical Information of China (English)

    Jiren Zhang; Yubo Wang; Jincheng Zhang

    2012-01-01

    A preliminary study by our research group showed that 6-mm-long regeneration chamber bridging is equivalent to autologous nerve transplantation for the repair of 12-mm nerve defects.In this study,we compared the efficacy of different lengths (6,8,10 mm) of nerve fragments bridging 6-mm regeneration chambers for the repair of 12-mm-long nerve defects.At 16 weeks after the regeneration chamber was implanted,the number,diameter and myelin sheath thickness of the regenerated nerve fibers,as well as the conduction velocity of the sciatic nerve and gastrocnemius muscle wet weight ratio,were similar to that observed with autologous nerve transplantation.Our results demonstrate that 6-,8-and 10-mm-long nerve fragments bridging 6-mm regeneration chambers effectively repair 12-mm-long nerve defects.Because the chemoattractive capacity is not affected by the length of the nerve fragment,we suggest adopting 6-mm-long nerve fragments for the repair of peripheral nerve defects.

  2. Auditory Spatial Layout

    Science.gov (United States)

    Wightman, Frederic L.; Jenison, Rick

    1995-01-01

    All auditory sensory information is packaged in a pair of acoustical pressure waveforms, one at each ear. While there is obvious structure in these waveforms, that structure (temporal and spectral patterns) bears no simple relationship to the structure of the environmental objects that produced them. The properties of auditory objects and their layout in space must be derived completely from higher level processing of the peripheral input. This chapter begins with a discussion of the peculiarities of acoustical stimuli and how they are received by the human auditory system. A distinction is made between the ambient sound field and the effective stimulus to differentiate the perceptual distinctions among various simple classes of sound sources (ambient field) from the known perceptual consequences of the linear transformations of the sound wave from source to receiver (effective stimulus). Next, the definition of an auditory object is dealt with, specifically the question of how the various components of a sound stream become segregated into distinct auditory objects. The remainder of the chapter focuses on issues related to the spatial layout of auditory objects, both stationary and moving.

  3. The morphological substrate for Renal Denervation: Nerve distribution patterns and parasympathetic nerves. A post-mortem histological study.

    Science.gov (United States)

    van Amsterdam, Wouter A C; Blankestijn, Peter J; Goldschmeding, Roel; Bleys, Ronald L A W

    2016-03-01

    Renal Denervation as a possible treatment for hypertension has been studied extensively, but knowledge on the distribution of nerves surrounding the renal artery is still incomplete. While sympathetic and sensory nerves have been demonstrated, there is no mention of the presence of parasympathetic nerve fibers. To provide a description of the distribution patterns of the renal nerves in man, and, in addition, provide a detailed representation of the relative contribution of the sympathetic, parasympathetic and afferent divisions of the autonomic nervous system. Renal arteries of human cadavers were each divided into four longitudinal segments and immunohistochemically stained with specific markers for afferent, parasympathetic and sympathetic nerves. Nerve fibers were semi-automatically quantified by computerized image analysis, and expressed as cross-sectional area relative to the distance to the lumen. A total of 3372 nerve segments were identified in 8 arteries of 7 cadavers. Sympathetic, parasympathetic and afferent nerves contributed for 73.5% (95% CI: 65.4-81.5%), 17.9% (10.7-25.1%) and 8.7% (5.0-12.3%) of the total cross-sectional nerve area, respectively. Nerves are closer to the lumen in more distal segments and larger bundles that presumably innervate the kidney lie at 1-3.5mm distance from the lumen. The tissue-penetration depth of the ablation required to destroy 50% of the nerve fibers is 2.37 mm in the proximal segment and 1.78 mm in the most distal segments. Sympathetic, parasympathetic and afferent nerves exist in the vicinity of the renal artery. The results warrant further investigation of the role of the parasympathetic nervous system on renal physiology, and may contribute to refinement of the procedure by focusing the ablation on the most distal segment. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Small vestibular schwannomas presenting with facial nerve palsy.

    Science.gov (United States)

    Espahbodi, Mana; Carlson, Matthew L; Fang, Te-Yung; Thompson, Reid C; Haynes, David S

    2014-06-01

    To describe the surgical management and convalescence of two patients presenting with severe facial nerve weakness associated with small intracanalicular vestibular schwannomas (VS). Retrospective review. Two adult female patients presenting with audiovestibular symptoms and subacute facial nerve paralysis (House-Brackmann Grade IV and V). In both cases, post-contrast T1-weighted magnetic resonance imaging revealed an enhancing lesion within the internal auditory canal without lateral extension beyond the fundus. Translabyrinthine exploration demonstrated vestibular nerve origin of tumor, extrinsic to the facial nerve, and frozen section pathology confirmed schwannoma. Gross total tumor resection with VIIth cranial nerve preservation and decompression of the labyrinthine segment of the facial nerve was performed. Both patients recovered full motor function between 6 and 8 months after surgery. Although rare, small VS may cause severe facial neuropathy, mimicking the presentation of facial nerve schwannomas and other less common pathologies. In the absence of labyrinthine extension on MRI, surgical exploration is the only reliable means of establishing a diagnosis. In the case of confirmed VS, early gross total resection with facial nerve preservation and labyrinthine segment decompression may afford full motor recovery-an outcome that cannot be achieved with facial nerve grafting.

  5. Microvascular Cranial Nerve Palsy

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Microvascular Cranial Nerve Palsy Sections What Is Microvascular Cranial Nerve Palsy? ... Microvascular Cranial Nerve Palsy Treatment What Is Microvascular Cranial Nerve Palsy? Leer en Español: ¿Qué es una parálisis ...

  6. Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres: multiple amplification of axonal regeneration

    Directory of Open Access Journals (Sweden)

    Yu-hui Kou

    2015-01-01

    Full Text Available Multiple-bud regeneration, i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve fiber regeneration. Our previous studies have verified the limit and validity of multiple amplification of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple amplification of myelinated nerve fiber regeneration in the primate peripheral nerve. Rhesus monkey models of distal ulnar nerve defects were established and repaired using muscular branches of the right forearm pronator teres. Proximal muscular branches of the pronator teres were sutured into the distal ulnar nerve using the small gap sleeve bridging method. At 6 months after suture, two-finger flexion and mild wrist flexion were restored in the ulnar-sided injured limbs of rhesus monkey. Neurophysiological examination showed that motor nerve conduction velocity reached 22.63 ± 6.34 m/s on the affected side of rhesus monkey. Osmium tetroxide staining demonstrated that the number of myelinated nerve fibers was 1,657 ± 652 in the branches of pronator teres of donor, and 2,661 ± 843 in the repaired ulnar nerve. The rate of multiple amplification of regenerating myelinated nerve fibers was 1.61. These data showed that when muscular branches of the pronator teres were used to repair ulnar nerve in primates, effective regeneration was observed in regenerating nerve fibers, and functions of the injured ulnar nerve were restored to a certain extent. Moreover, multiple amplification was subsequently detected in ulnar nerve axons.

  7. Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres: multiple amplification of axonal regeneration.

    Science.gov (United States)

    Kou, Yu-Hui; Zhang, Pei-Xun; Wang, Yan-Hua; Chen, Bo; Han, Na; Xue, Feng; Zhang, Hong-Bo; Yin, Xiao-Feng; Jiang, Bao-Guo

    2015-01-01

    Multiple-bud regeneration, i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve fiber regeneration. Our previous studies have verified the limit and validity of multiple amplification of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple amplification of myelinated nerve fiber regeneration in the primate peripheral nerve. Rhesus monkey models of distal ulnar nerve defects were established and repaired using muscular branches of the right forearm pronator teres. Proximal muscular branches of the pronator teres were sutured into the distal ulnar nerve using the small gap sleeve bridging method. At 6 months after suture, two-finger flexion and mild wrist flexion were restored in the ulnar-sided injured limbs of rhesus monkey. Neurophysiological examination showed that motor nerve conduction velocity reached 22.63 ± 6.34 m/s on the affected side of rhesus monkey. Osmium tetroxide staining demonstrated that the number of myelinated nerve fibers was 1,657 ± 652 in the branches of pronator teres of donor, and 2,661 ± 843 in the repaired ulnar nerve. The rate of multiple amplification of regenerating myelinated nerve fibers was 1.61. These data showed that when muscular branches of the pronator teres were used to repair ulnar nerve in primates, effective regeneration was observed in regenerating nerve fibers, and functions of the injured ulnar nerve were restored to a certain extent. Moreover, multiple amplification was subsequently detected in ulnar nerve axons.

  8. Equivalente esférico e valores da espessura da camada de fibras nervosas obtidas com o GDX TM Scanning Laser System® Spherical equivalent and nerve fiber layer thickness assessed with GDX TM Scanning Laser System®

    Directory of Open Access Journals (Sweden)

    Lênio Souza Alvarenga

    1999-12-01

    Full Text Available Objetivo: Estudar a influência do equivalente esférico nos valores obtidos pelo GDX TM Scanning Laser System®. Métodos: Foram avaliados 41 olhos de 41 voluntários sem doenças oculares e com campo visual sem alterações. Foi realizada a polarimetria de varredura a laser com o GDX TM Scanning Laser System® de acordo com as instruções contidas no manual do aparelho. Foram comparados os valores obtidos nesse exame em um grupo de pacientes com equivalente esférico positivo e em um outro com este valor nulo ou negativo, pelo teste de Mann-Whitney. Resultados: Não se verificou diferença estatística entre os valores obtidos nos olhos de pacientes do grupo I e os do grupo II. Não foi encontrada correlação entre o equivalente esférico e os valores obtidos com o GDX TM Scanning Laser System®. Conclusões: Na amostra estudada não houve diferença estatística entre os valores obtidos em um grupo de olhos com equivalente esférico positivo e outro com este valor negativo ou nulo, usando-se o GDX TM Scanning Laser System®.Purpose: To evaluate the effect of spherical equivalent on the acquisition of nerve fiber layer (NFL thickness with GDX TM Scanning Laser System®. Methods: Forty-one eyes of 41 volunteers were enrolled in this study. All of them presented with no ocular disease and no visual field defect. The NFL thickness was measured with GDX TM Scanning Laser System® as described in its manual. The values obtained in a group of volunteers with negative spherical equivalent (group I were compared to those from a group with a positive spherical equivalent (group II by the Mann-Whitney test. Results: There was no statistical difference between mea-surements in eyes of group I and those in group II. The NFL thickness measurements were not correlated with the sphe-rical equivalent. Conclusions: In the studied group there was no statistical difference in the GDX TM Scanning Laser System® parameters related to spherical equivalent.

  9. Preoperative diffusion tensor imaging-fiber tracking for facial nerve identification in vestibular schwannoma: a systematic review on its evolution and current status with a pooled data analysis of surgical concordance rates.

    Science.gov (United States)

    Savardekar, Amey R; Patra, Devi P; Thakur, Jai D; Narayan, Vinayak; Mohammed, Nasser; Bollam, Papireddy; Nanda, Anil

    2018-03-01

    OBJECTIVE Total tumor excision with the preservation of neurological function and quality of life is the goal of modern-day vestibular schwannoma (VS) surgery. Postoperative facial nerve (FN) paralysis is a devastating complication of VS surgery. Determining the course of the FN in relation to a VS preoperatively is invaluable to the neurosurgeon and is likely to enhance surgical safety with respect to FN function. Diffusion tensor imaging-fiber tracking (DTI-FT) technology is slowly gaining traction as a viable tool for preoperative FN visualization in patients with VS. METHODS A systematic review of the literature in the PubMed, Cochrane Library, and Web of Science databases was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and those studies that preoperatively localized the FN in relation to a VS using the DTI-FT technique and verified those preoperative FN tracking results by using microscopic observation and electrophysiological monitoring during microsurgery were included. A pooled analysis of studies was performed to calculate the surgical concordance rate (accuracy) of DTI-FT technology for FN localization. RESULTS Fourteen studies included 234 VS patients (male/female ratio 1:1.4, age range 17-75 years) who had undergone preoperative DTI-FT for FN identification. The mean tumor size among the studies ranged from 29 to 41.3 mm. Preoperative DTI-FT could not visualize the FN tract in 8 patients (3.4%) and its findings could not be verified in 3 patients (1.2%), were verified but discordant in 18 patients (7.6%), and were verified and concordant in 205 patients (87.1%). CONCLUSIONS Preoperative DTI-FT for FN identification is a useful adjunct in the surgical planning for large VSs (> 2.5 cm). A pooled analysis showed that DTI-FT successfully identifies the complete FN course in 96.6% of VSs (226 of 234 cases) and that FN identification by DTI-FT is accurate in 90.6% of cases (205 of 226

  10. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect.

    Science.gov (United States)

    Luo, Lihua; Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan; Wang, Xiong; Huselstein, Celine; Chen, Yun

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  11. The significance of a hypoplastic bony canal for the cochlear nerve in patients with sensorineural hearing loss: CT and MRI findings

    International Nuclear Information System (INIS)

    Choi, Yoon Jung; Park, Sang Yoo; Kim, Myung Soon; Sung, Ki Jun

    2004-01-01

    The purpose of this study is to evaluate the significance of the hypoplastic canal for the cochlear nerve in patients with sensorineural hearing loss (SNHL) and the relationship between the hypoplastic bony canal and aplasia or hypoplasia of the cochlear nerve. A retrospective review of high resolution temporal CT(HRCT) and MRI findings was conducted. The narrow bony canal of the cochlear nerve and the relative size of the internal auditory canal were correlated with the cochlear nerve deficiency on MRI. The comparative size of the component nerves (facial, cochlear, superior vestibular, inferior vestibular nerve), and the relative size of the internal auditory canal and the bony canal of the cochlear nerve were measured. The clinical history and the results of the clinical examination were reviewed for each patient. High resolution MRI showed aplasia of the common vestibulocochlear nerve in one patient and a deficiency of the cochlear nerve in 9 patients. These abnormalities occurred in association with a prominent narrowing of the canal for the cochlear nerve and a stenosis of the internal auditory canal, which was observed on temporal bone CT in 9 patients with congenital SNHL. Three patients had normal IAC, despite the presence of a hypoplastic cochlear nerve on the side on which they had SNHL. In one patient, the narrowing of the canal for the cochlear nerve and internal auditory canal were not found to be associated with acquired SNHL. The hypoplastic bony canal for the cochlear nerve might be more highly indicative of congenital cochlear nerve deficiency than that of the narrow internal auditory canal, and the position of the crista falciformis should also be carefully

  12. The significance of a hypoplastic bony canal for the cochlear nerve in patients with sensorineural hearing loss: CT and MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yoon Jung; Park, Sang Yoo; Kim, Myung Soon; Sung, Ki Jun [College of Medicine, Yonsei Univ., Wonju (Korea, Republic of)

    2004-04-01

    The purpose of this study is to evaluate the significance of the hypoplastic canal for the cochlear nerve in patients with sensorineural hearing loss (SNHL) and the relationship between the hypoplastic bony canal and aplasia or hypoplasia of the cochlear nerve. A retrospective review of high resolution temporal CT(HRCT) and MRI findings was conducted. The narrow bony canal of the cochlear nerve and the relative size of the internal auditory canal were correlated with the cochlear nerve deficiency on MRI. The comparative size of the component nerves (facial, cochlear, superior vestibular, inferior vestibular nerve), and the relative size of the internal auditory canal and the bony canal of the cochlear nerve were measured. The clinical history and the results of the clinical examination were reviewed for each patient. High resolution MRI showed aplasia of the common vestibulocochlear nerve in one patient and a deficiency of the cochlear nerve in 9 patients. These abnormalities occurred in association with a prominent narrowing of the canal for the cochlear nerve and a stenosis of the internal auditory canal, which was observed on temporal bone CT in 9 patients with congenital SNHL. Three patients had normal IAC, despite the presence of a hypoplastic cochlear nerve on the side on which they had SNHL. In one patient, the narrowing of the canal for the cochlear nerve and internal auditory canal were not found to be associated with acquired SNHL. The hypoplastic bony canal for the cochlear nerve might be more highly indicative of congenital cochlear nerve deficiency than that of the narrow internal auditory canal, and the position of the crista falciformis should also be carefully.

  13. First Branchial Cleft Fistula Associated with External Auditory Canal Stenosis and Middle Ear Cholesteatoma

    Science.gov (United States)

    Abdollahi fakhim, Shahin; Naderpoor, Masoud; Mousaviagdas, Mehrnoosh

    2014-01-01

    Introduction: First branchial cleft anomalies manifest with duplication of the external auditory canal. Case Report: This report features a rare case of microtia and congenital middle ear and canal cholesteatoma with first branchial fistula. External auditory canal stenosis was complicated by middle ear and external canal cholesteatoma, but branchial fistula, opening in the zygomatic root and a sinus in the helical root, may explain this feature. A canal wall down mastoidectomy with canaloplasty and wide meatoplasty was performed. The branchial cleft was excised through parotidectomy and facial nerve dissection. Conclusion: It should be considered that canal stenosis in such cases can induce cholesteatoma formation in the auditory canal and middle ear. PMID:25320705

  14. First branchial cleft fistula associated with external auditory canal stenosis and middle ear cholesteatoma.

    Science.gov (United States)

    Abdollahi Fakhim, Shahin; Naderpoor, Masoud; Mousaviagdas, Mehrnoosh

    2014-10-01

    First branchial cleft anomalies manifest with duplication of the external auditory canal. This report features a rare case of microtia and congenital middle ear and canal cholesteatoma with first branchial fistula. External auditory canal stenosis was complicated by middle ear and external canal cholesteatoma, but branchial fistula, opening in the zygomatic root and a sinus in the helical root, may explain this feature. A canal wall down mastoidectomy with canaloplasty and wide meatoplasty was performed. The branchial cleft was excised through parotidectomy and facial nerve dissection. It should be considered that canal stenosis in such cases can induce cholesteatoma formation in the auditory canal and middle ear.

  15. Integration of auditory and visual speech information

    NARCIS (Netherlands)

    Hall, M.; Smeele, P.M.T.; Kuhl, P.K.

    1998-01-01

    The integration of auditory and visual speech is observed when modes specify different places of articulation. Influences of auditory variation on integration were examined using consonant identifi-cation, plus quality and similarity ratings. Auditory identification predicted auditory-visual

  16. Quantitative Microscopic Analysis of Myelinated Nerve Fibers

    NARCIS (Netherlands)

    Prodanov, D.P.; Feierabend, Hans K.P.; Marani, Enrico; Costa, A.; Villalba, E.

    2010-01-01

    Horizons in Neuroscience Research presents original research results on the leading edge of neuroscience research. Each article has been carefully selected in an attempt to present substantial research results across a broad spectrum

  17. Quantitative Microscopic Analysis of Myelinated Nerve Fibers

    NARCIS (Netherlands)

    Prodanov, D.P.; Feierabend, Hans K.P.; Marani, Enrico; Flynn, Cian E.; Callaghan, Brandon R.

    2010-01-01

    Neuroanatomy is the study of the anatomical organization of the brain. Reciprocal communication between the brain and the cardiovascular system is important in sustaining neurobehavioral states that allow organisms to cope with their environment. Furthermore, in vertebrate animals, the routes that

  18. Distinction of neurochemistry between the cores and their shells of auditory nuclei in tetrapod species.

    Science.gov (United States)

    Zeng, ShaoJu; Li, Jia; Zhang, XinWen; Zuo, MingXue

    2007-01-01

    The distribution of Met-enkephalin (ENK), substance P (SP) and serotonin (5-HT) differs between the core and shell regions of the mesencephalic and diencephalic auditory nuclei of the turtle [Belekhova et al., 2002]. These neurochemical distinctions are also found in other tetrapods (mammals, birds and amphibians). The distribution of ENK, SP and 5-HT was examined in the core and shell regions of both mesencephalic and diencephalic auditory nuclei, and in the telencephalic auditory areas of Bengalese finches (Lonchura striata) and mice (Mus musculus), as well as in corresponding auditory areas in toads (Bufo bufo). ENK, SP and 5-HT immunoreactive fibers and perikarya were largely absent from the core regions of both mesencephalic and diencephalic auditory nuclei, in comparison with the shell regions of mice and Bengalese finches. In the toad, however, this pattern was observed in the mesencephalic auditory nucleus, but not in the diencephalic auditory areas. ENK and SP immunoreactive perikarya were detected in the telencephalic auditory area of mice, whereas no ENK, SP or 5-HT immunolabeling was observed in the telencephalic auditory area (Field L) of Bengalese finches. These findings are discussed in terms of the evolution of the core-and-shell organization of auditory nuclei of tetrapods. Copyright 2007 S. Karger AG, Basel.

  19. Internal auditory canal (IAC) stenosis: imaging Findings

    International Nuclear Information System (INIS)

    Ortiz Jimenez, Johanna; Roa, Jose Luis; Figuero A, Ramon E

    2011-01-01

    Objectives: To describe the computed tomography (CT) and magnetic resonance (MR) findings in a patient with a diagnosis of internal auditory canal (IAC) stenosis. To describe the embryological development of the IAC structures and the natural history of IAC stenosis. Methods: A 4 year old girl presents with sensorineural hearing loss and bilateral recurrent otitis media. The temporal bone CT shows diminished left IAC diameter (less than 2 mm), right IAC absence and normal inner ear structures. These findings are pathognomonic for left IAC stenosis. The MR findings include left IAC stenosis and IAC neural structures absence secondary to aplasia of the vestibulocochlear nerve on each IAC . Results: Hypoplasia/aplasia of the vestibulocochlear nerve in association with IAC stenosis is an important consideration in the differential diagnosis of sensorineural hearing loss, as it is a relative contraindication for cochlear implant placement. Conclusions: IAC stenosis and vestibulocochlear nerve hypoplasia/aplasia must be excluded as an etiology of sensorineural hearing loss. The diagnosis can be made by CT and MR.

  20. Internal auditory canal (IAC) stenosis: Imaging findings

    International Nuclear Information System (INIS)

    Ortiz J, Johanna; Roa, Jose L; Figueroa Ramon E

    2011-01-01

    Objectives: To describe the computed tomography (CT) and magnetic resonance (MR) findings in a patient with a diagnosis of internal auditory canal (IAC) stenosis. To describe the embryological development of the IAC structures and the natural history of IAC stenosis. Methods: A 4 year old girl presents with sensorineural hearing loss and bilateral recurrent otitis media. The temporal bone CT shows diminished left IAC diameter (less than 2 mm), right IAC absence and normal inner ear structures. These findings are pathognomonic for left IAC stenosis. The MR findings include left IAC stenosis and IAC neural structures absence secondary to aplasia of the vestibulocochlear nerve on each IAC. Results: Hypoplasia/aplasia of the vestibulocochlear nerve in association with IAC stenosis is an important consideration in the differential diagnosis of sensorineural hearing loss, as it is a relative contraindication for cochlear implant placement. Conclusions: IAC stenosis and vestibulocochlear nerve hypoplasia/aplasia must be excluded as an etiology of sensorineural hearing loss. The diagnosis can be made by CT and MR.

  1. Label-free photoacoustic microscopy of peripheral nerves

    Science.gov (United States)

    Matthews, Thomas Paul; Zhang, Chi; Yao, Da-Kang; Maslov, Konstantin; Wang, Lihong V.

    2014-01-01

    Peripheral neuropathy is a common neurological problem that affects millions of people worldwide. Diagnosis and treatment of this condition are often hindered by the difficulties in making objective, noninvasive measurements of nerve fibers. Photoacoustic microscopy (PAM) has the ability to obtain high resolution, specific images of peripheral nerves without exogenous contrast. We demonstrated the first proof-of-concept imaging of peripheral nerves using PAM. As validated by both standard histology and photoacoustic spectroscopy, the origin of photoacoustic signals is myelin, the primary source of lipids in the nerves. An extracted sciatic nerve sandwiched between two layers of chicken tissue was imaged by PAM to mimic the in vivo case. Ordered fibrous structures inside the nerve, caused by the bundles of myelin-coated axons, could be observed clearly. With further technical improvements, PAM can potentially be applied to monitor and diagnose peripheral neuropathies.

  2. Perception of stochastically undersampled sound waveforms: A model of auditory deafferentation

    Directory of Open Access Journals (Sweden)

    Enrique A Lopez-Poveda

    2013-07-01

    Full Text Available Auditory deafferentation, or permanent loss of auditory nerve afferent terminals, occurs after noise overexposure and aging and may accompany many forms of hearing loss. It could cause significant auditory impairment but is undetected by regular clinical tests and so its effects on perception are poorly understood. Here, we hypothesize and test a neural mechanism by which deafferentation could deteriorate perception. The basic idea is that the spike train produced by each auditory afferent resembles a stochastically digitized version of the sound waveform and that the quality of the waveform representation in the whole nerve depends on the number of aggregated spike trains or auditory afferents. We reason that because spikes occur stochastically in time with a higher probability for high- than for low-intensity sounds, more afferents would be required for the nerve to faithfully encode high-frequency or low-intensity waveform features than low-frequency or high-intensity features. Deafferentation would thus degrade the encoding of these features. We further reason that due to the stochastic nature of nerve firing, the degradation would be greater in noise than in quiet. This hypothesis is tested using a vocoder. Sounds were filtered through ten adjacent frequency bands. For the signal in each band, multiple stochastically subsampled copies were obtained to roughly mimic different stochastic representations of that signal conveyed by different auditory afferents innervating a given cochlear region. These copies were then aggregated to obtain an acoustic stimulus. Tone detection and speech identification tests were performed by young, normal-hearing listeners using different numbers of stochastic samplers per frequency band in the vocoder. Results support the hypothesis that stochastic undersampling of the sound waveform, inspired by deafferentation, impairs speech perception in noise more than in quiet, consistent with auditory aging effects.

  3. Perception of stochastically undersampled sound waveforms: a model of auditory deafferentation

    Science.gov (United States)

    Lopez-Poveda, Enrique A.; Barrios, Pablo

    2013-01-01

    Auditory deafferentation, or permanent loss of auditory nerve afferent terminals, occurs after noise overexposure and aging and may accompany many forms of hearing loss. It could cause significant auditory impairment but is undetected by regular clinical tests and so its effects on perception are poorly understood. Here, we hypothesize and test a neural mechanism by which deafferentation could deteriorate perception. The basic idea is that the spike train produced by each auditory afferent resembles a stochastically digitized version of the sound waveform and that the quality of the waveform representation in the whole nerve depends on the number of aggregated spike trains or auditory afferents. We reason that because spikes occur stochastically in time with a higher probability for high- than for low-intensity sounds, more afferents would be required for the nerve to faithfully encode high-frequency or low-intensity waveform features than low-frequency or high-intensity features. Deafferentation would thus degrade the encoding of these features. We further reason that due to the stochastic nature of nerve firing, the degradation would be greater in noise than in quiet. This hypothesis is tested using a vocoder. Sounds were filtered through ten adjacent frequency bands. For the signal in each band, multiple stochastically subsampled copies were obtained to roughly mimic different stochastic representations of that signal conveyed by different auditory afferents innervating a given cochlear region. These copies were then aggregated to obtain an acoustic stimulus. Tone detection and speech identification tests were performed by young, normal-hearing listeners using different numbers of stochastic samplers per frequency band in the vocoder. Results support the hypothesis that stochastic undersampling of the sound waveform, inspired by deafferentation, impairs speech perception in noise more than in quiet, consistent with auditory aging effects. PMID:23882176

  4. Auditory and Visual Sensations

    CERN Document Server

    Ando, Yoichi

    2010-01-01

    Professor Yoichi Ando, acoustic architectural designer of the Kirishima International Concert Hall in Japan, presents a comprehensive rational-scientific approach to designing performance spaces. His theory is based on systematic psychoacoustical observations of spatial hearing and listener preferences, whose neuronal correlates are observed in the neurophysiology of the human brain. A correlation-based model of neuronal signal processing in the central auditory system is proposed in which temporal sensations (pitch, timbre, loudness, duration) are represented by an internal autocorrelation representation, and spatial sensations (sound location, size, diffuseness related to envelopment) are represented by an internal interaural crosscorrelation function. Together these two internal central auditory representations account for the basic auditory qualities that are relevant for listening to music and speech in indoor performance spaces. Observed psychological and neurophysiological commonalities between auditor...

  5. Análise de Fourier para detecção de defeitos localizados na camada de fibras nervosas da retina com a polarimetria a laser Fourier analysis for the detection of localized nerve fiber layer defects using scanning laser polarimetry

    Directory of Open Access Journals (Sweden)

    Felipe Andrade Medeiros

    2003-12-01

    Full Text Available OBJETIVO: Avaliar a utilidade da análise de Fourier como método para detecção de defeitos localizados na camada de fibras nervosas da retina (CFN, utilizando as medidas obtidas com a polarimetria de varredura a laser. MÉTODOS: O estudo incluiu 40 olhos de 40 pacientes com glaucoma apresentando defeitos localizados na CFN detectados à oftalmoscopia e/ou em fotografias da camada de fibras nervosas. O grupo controle foi constituído por 43 olhos de 43 pacientes normais, sem antecedente de pressão intra-ocular elevada ou glaucoma, e com exame normal da CFN e disco óptico. Todos os pacientes foram submetidos a exame da CFN utilizando o aparelho GDx® - Nerve Fiber Analyzer. Para comparação entre os grupos, foram utilizados os parâmetros fornecidos pelo software do aparelho e medidas provenientes dos coeficientes obtidos pela análise de Fourier da curva de distribuição dos valores de espessura da CFN. As várias medidas dos coeficientes de Fourier foram combinadas numa função linear discriminante de maneira a encontrar a combinação que resultasse na melhor separação entre pacientes glaucomatosos com defeitos localizados e os sujeitos normais. Curvas ROC foram construídas para cada medida e valores de sensibilidade para especificidades fixas foram calculados. RESULTADOS: Os parâmetros fornecidos pelo software do GDx mostraram baixo poder de diferenciação entre os pacientes normais e com defeitos localizados na CFN, com sensibilidades variando de 15 a 48% (com especificidade a 91%. Para a mesma especificidade de 91%, a combinação dos coeficientes de Fourier teve sensibilidade de 80%. A área sob a curva ROC para a combinação dos coeficientes de Fourier (0,90 foi significativamente superior à obtida para o parâmetro The Number (0,76. CONCLUSÃO: A análise de Fourier resultou em melhora na capacidade do GDx de detectar defeitos localizados na CFN em relação aos parâmetros fornecidos pelo software do aparelho.PURPOSE: In

  6. Modularity in Sensory Auditory Memory

    OpenAIRE

    Clement, Sylvain; Moroni, Christine; Samson, Séverine

    2004-01-01

    The goal of this paper was to review various experimental and neuropsychological studies that support the modular conception of auditory sensory memory or auditory short-term memory. Based on initial findings demonstrating that verbal sensory memory system can be dissociated from a general auditory memory store at the functional and anatomical levels. we reported a series of studies that provided evidence in favor of multiple auditory sensory stores specialized in retaining eit...

  7. Age-related ultrastructural and monoamine oxidase changes in the rat optic nerve.

    Science.gov (United States)

    Taurone, S; Ripandelli, G; Minni, A; Lattanzi, R; Miglietta, S; Pepe, N; Fumagalli, L; Micera, A; Pastore, F S; Artico, M

    2016-01-01

    The aim of this paper is to study the morphology and the distribution of the monoamine oxidase enzymatic system in the optic nerve of 4 month-old Wistar (young) and 28 month-old Wistar (old) rats. The optic nerve was harvested from 20 young and old rats. The segment of optic nerve was divided longitudinally into two pieces, each 0.1 mm in length. The first piece was used for transmission electron microscopy. The second piece was stained with histochemical reaction for monoamine oxidase. The agerelated changes in the optic nerve of rats include micro-anatomical details, ultrastructure and monoamine oxidase histochemical staining. A strong decrease of the thin nerve fibers and a swelling of the thick ones can be observed in optic nerve fibers of old rats. Increased monoamine oxidase histochemical staining of the optic nerve of aged rats is well demonstrated. The increase of meningeal shealth and the decrease of thin nerve fibers of the optic nerve in old rats are well documented. Morphological, ultrastructural and histochemical changes observed in optic nerve fibers of the old rats show a close relation with aging.

  8. Comprehensive evaluation of a child with an auditory brainstem implant.

    Science.gov (United States)

    Eisenberg, Laurie S; Johnson, Karen C; Martinez, Amy S; DesJardin, Jean L; Stika, Carren J; Dzubak, Danielle; Mahalak, Mandy Lutz; Rector, Emily P

    2008-02-01

    We had an opportunity to evaluate an American child whose family traveled to Italy to receive an auditory brainstem implant (ABI). The goal of this evaluation was to obtain insight into possible benefits derived from the ABI and to begin developing assessment protocols for pediatric clinical trials. Case study. Tertiary referral center. Pediatric ABI Patient 1 was born with auditory nerve agenesis. Auditory brainstem implant surgery was performed in December, 2005, in Verona, Italy. The child was assessed at the House Ear Institute, Los Angeles, in July 2006 at the age of 3 years 11 months. Follow-up assessment has continued at the HEAR Center in Birmingham, Alabama. Auditory brainstem implant. Performance was assessed for the domains of audition, speech and language, intelligence and behavior, quality of life, and parental factors. Patient 1 demonstrated detection of sound, speech pattern perception with visual cues, and inconsistent auditory-only vowel discrimination. Language age with signs was approximately 2 years, and vocalizations were increasing. Of normal intelligence, he exhibited attention deficits with difficulty completing structured tasks. Twelve months later, this child was able to identify speech patterns consistently; closed-set word identification was emerging. These results were within the range of performance for a small sample of similarly aged pediatric cochlear implant users. Pediatric ABI assessment with a group of well-selected children is needed to examine risk versus benefit in this population and to analyze whether open-set speech recognition is achievable.

  9. Auditory Neural Prostheses – A Window to the Future

    Directory of Open Access Journals (Sweden)

    Mohan Kameshwaran

    2015-06-01

    Full Text Available Hearing loss is one of the commonest congenital anomalies to affect children world-over. The incidence of congenital hearing loss is more pronounced in developing countries like the Indian sub-continent, especially with the problems of consanguinity. Hearing loss is a double tragedy, as it leads to not only deafness but also language deprivation. However, hearing loss is the only truly remediable handicap, due to remarkable advances in biomedical engineering and surgical techniques. Auditory neural prostheses help to augment or restore hearing by integration of an external circuitry with the peripheral hearing apparatus and the central circuitry of the brain. A cochlear implant (CI is a surgically implantable device that helps restore hearing in patients with severe-profound hearing loss, unresponsive to amplification by conventional hearing aids. CIs are electronic devices designed to detect mechanical sound energy and convert it into electrical signals that can be delivered to the coch­lear nerve, bypassing the damaged hair cells of the coch­lea. The only true prerequisite is an intact auditory nerve. The emphasis is on implantation as early as possible to maximize speech understanding and perception. Bilateral CI has significant benefits which include improved speech perception in noisy environments and improved sound localization. Presently, the indications for CI have widened and these expanded indications for implantation are related to age, additional handicaps, residual hearing, and special etiologies of deafness. Combined electric and acoustic stimulation (EAS / hybrid device is designed for individuals with binaural low-frequency hearing and severe-to-profound high-frequency hearing loss. Auditory brainstem implantation (ABI is a safe and effective means of hearing rehabilitation in patients with retrocochlear disorders, such as neurofibromatosis type 2 (NF2 or congenital cochlear nerve aplasia, wherein the cochlear nerve is damaged

  10. Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: An autoradiographic and immunohistochemical study

    International Nuclear Information System (INIS)

    Hof, P.R.; Dietl, M.M.; Charnay, Y.; Martin, J.L.; Bouras, C.; Palacios, J.M.; Magistretti, P.J.

    1991-01-01

    The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves

  11. Parkinson disease affects peripheral sensory nerves in the pharynx.

    Science.gov (United States)

    Mu, Liancai; Sobotka, Stanislaw; Chen, Jingming; Su, Hungxi; Sanders, Ira; Nyirenda, Themba; Adler, Charles H; Shill, Holly A; Caviness, John N; Samanta, Johan E; Sue, Lucia I; Beach, Thomas G

    2013-07-01

    Dysphagia is very common in patients with Parkinson disease (PD) and often leads to aspiration pneumonia, the most common cause of death in PD. Current therapies are largely ineffective for dysphagia. Because pharyngeal sensation normally triggers the swallowing reflex, we examined pharyngeal sensory nerves in PD patients for Lewy pathology.Sensory nerves supplying the pharynx were excised from autopsied pharynges obtained from patients with clinically diagnosed and neuropathologically confirmed PD (n = 10) and healthy age-matched controls (n = 4). We examined the glossopharyngeal nerve (cranial nerve IX), the pharyngeal sensory branch of the vagus nerve (PSB-X), and the internal superior laryngeal nerve (ISLN) innervating the laryngopharynx. Immunohistochemistry for phosphorylated α-synuclein was used to detect Lewy pathology. Axonal α-synuclein aggregates in the pharyngeal sensory nerves were identified in all of the PD subjects but not in the controls. The density of α-synuclein-positive lesions was greater in PD patients with dysphagia versus those without dysphagia. In addition, α-synuclein-immunoreactive nerve fibers in the ISLN were much more abundant than those in cranial nerve IX and PSB-X. These findings suggest that pharyngeal sensory nerves are directly affected by pathologic processes in PD. These abnormalities may decrease pharyngeal sensation, thereby impairing swallowing and airway protective reflexes and contributing to dysphagia and aspiration.

  12. Radial nerve dysfunction (image)

    Science.gov (United States)

    The radial nerve travels down the arm and supplies movement to the triceps muscle at the back of the upper arm. ... the wrist and hand. The usual causes of nerve dysfunction are direct trauma, prolonged pressure on the ...

  13. Degenerative Nerve Diseases

    Science.gov (United States)

    Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many ... viruses. Sometimes the cause is not known. Degenerative nerve diseases include Alzheimer's disease Amyotrophic lateral sclerosis Friedreich's ...

  14. Nerve conduction velocity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

  15. Distal median nerve dysfunction

    Science.gov (United States)

    ... later on. Inflammation of the tendons ( tendonitis ) or joints ( arthritis ) can also put pressure on the nerve. ... how fast electrical signals move through a nerve Neuromuscular ultrasound to view problems with the muscles and ...

  16. Gd-DTPA enhancement of the facial nerve in Ramsay Hunt's syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Tsutomu; Yanagida, Masahiro; Yamauchi, Yasuo (Kansai Medical School, Moriguchi, Osaka (Japan)) (and others)

    1992-10-01

    A total of 21 MR images in 16 Ramsay Hunt's syndrome were evaluated. In all images, the involved side of peripheral facial nerve were enhanced in intensity after Gd-DTPA. However, 2 cases had recovered facial palsy when MR images were taken. Nine of 19 cases with the enhancement of internal auditory canal portion had vertigo or tinnitus. Thus, it was suggested that the enhancement of internal auditory canal portion and clinical feature are closely related. (author).

  17. Gd-DTPA enhancement of the facial nerve in Ramsay Hunt's syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Tsutomu; Yanagida, Masahiro; Yamauchi, Yasuo [Kansai Medical School, Moriguchi, Osaka (Japan); and others

    1992-10-01

    A total of 21 MR images in 16 Ramsay Hunt's syndrome were evaluated. In all images, the involved side of peripheral facial nerve were enhanced in intensity after Gd-DTPA. However, 2 cases had recovered facial palsy when MR images were taken. Nine of 19 cases with the enhancement of internal auditory canal portion had vertigo or tinnitus. Thus, it was suggested that the enhancement of internal auditory canal portion and clinical feature are closely related. (author).

  18. Gd-DTPA enhancement of the facial nerve in Ramsay Hunt's syndrome

    International Nuclear Information System (INIS)

    Kato, Tsutomu; Yanagida, Masahiro; Yamauchi, Yasuo

    1992-01-01

    A total of 21 MR images in 16 Ramsay Hunt's syndrome were evaluated. In all images, the involved side of peripheral facial nerve were enhanced in intensity after Gd-DTPA. However, 2 cases had recovered facial palsy when MR images were taken. Nine of 19 cases with the enhancement of internal auditory canal portion had vertigo or tinnitus. Thus, it was suggested that the enhancement of internal auditory canal portion and clinical feature are closely related. (author)

  19. Reconstruction of the abdominal vagus nerve using sural nerve grafts in canine models.

    Science.gov (United States)

    Liu, Jingbo; Wang, Jun; Luo, Fen; Wang, Zhiming; Wang, Yin

    2013-01-01

    Recently, vagus nerve preservation or reconstruction of vagus has received increasing attention. The present study aimed to investigate the feasibility of reconstructing the severed vagal trunk using an autologous sural nerve graft. Ten adult Beagle dogs were randomly assigned to two groups of five, the nerve grafting group (TG) and the vagal resection group (VG). The gastric secretion and emptying functions in both groups were assessed using Hollander insulin and acetaminophen tests before surgery and three months after surgery. All dogs underwent laparotomy under general anesthesia. In TG group, latency and conduction velocity of the action potential in a vagal trunk were measured, and then nerves of 4 cm long were cut from the abdominal anterior and posterior vagal trunks. Two segments of autologous sural nerve were collected for performing end-to-end anastomoses with the cut ends of vagal trunk (8-0 nylon suture, 3 sutures for each anastomosis). Dogs in VG group only underwent partial resections of the anterior and posterior vagal trunks. Laparotomy was performed in dogs of TG group, and latency and conduction velocity of the action potential in their vagal trunks were measured. The grafted nerve segment was removed, and stained with anti-neurofilament protein and toluidine blue. Latency of the action potential in the vagal trunk was longer after surgery than before surgery in TG group, while the conduction velocity was lower after surgery. The gastric secretion and emptying functions were weaker after surgery in dogs of both groups, but in TG group they were significantly better than in VG group. Anti-neurofilament protein staining and toluidine blue staining showed there were nerve fibers crossing the anastomosis of the vagus and sural nerves in dogs of TG group. Reconstruction of the vagus nerve using the sural nerve is technically feasible.

  20. Reconstruction of the abdominal vagus nerve using sural nerve grafts in canine models.

    Directory of Open Access Journals (Sweden)

    Jingbo Liu

    Full Text Available BACKGROUND: Recently, vagus nerve preservation or reconstruction of vagus has received increasing attention. The present study aimed to investigate the feasibility of reconstructing the severed vagal trunk using an autologous sural nerve graft. METHODS: Ten adult Beagle dogs were randomly assigned to two groups of five, the nerve grafting group (TG and the vagal resection group (VG. The gastric secretion and emptying functions in both groups were assessed using Hollander insulin and acetaminophen tests before surgery and three months after surgery. All dogs underwent laparotomy under general anesthesia. In TG group, latency and conduction velocity of the action potential in a vagal trunk were measured, and then nerves of 4 cm long were cut from the abdominal anterior and posterior vagal trunks. Two segments of autologous sural nerve were collected for performing end-to-end anastomoses with the cut ends of vagal trunk (8-0 nylon suture, 3 sutures for each anastomosis. Dogs in VG group only underwent partial resections of the anterior and posterior vagal trunks. Laparotomy was performed in dogs of TG group, and latency and conduction velocity of the action potential in their vagal trunks were measured. The grafted nerve segment was removed, and stained with anti-neurofilament protein and toluidine blue. RESULTS: Latency of the action potential in the vagal trunk was longer after surgery than before surgery in TG group, while the conduction velocity was lower after surgery. The gastric secretion and emptying functions were weaker after surgery in dogs of both groups, but in TG group they were significantly better than in VG group. Anti-neurofilament protein staining and toluidine blue staining showed there were nerve fibers crossing the anastomosis of the vagus and sural nerves in dogs of TG group. CONCLUSION: Reconstruction of the vagus nerve using the sural nerve is technically feasible.

  1. Auditory Memory for Timbre

    Science.gov (United States)

    McKeown, Denis; Wellsted, David

    2009-01-01

    Psychophysical studies are reported examining how the context of recent auditory stimulation may modulate the processing of new sounds. The question posed is how recent tone stimulation may affect ongoing performance in a discrimination task. In the task, two complex sounds occurred in successive intervals. A single target component of one complex…

  2. Auditory evacuation beacons

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Bronkhorst, A.W.; Boer, L.C.

    2005-01-01

    Auditory evacuation beacons can be used to guide people to safe exits, even when vision is totally obscured by smoke. Conventional beacons make use of modulated noise signals. Controlled evacuation experiments show that such signals require explicit instructions and are often misunderstood. A new

  3. The effect of patient positioning on MR imaging of the internal auditory canal

    International Nuclear Information System (INIS)

    Daniels, D.L.; Czervionke, L.F.; Yu, S.; Ho, P.S.P.; Pech, P.; Pojunas, K.W.; Williams, A.L.; Haughton, V.M.

    1988-01-01

    Identification of individual cranial nerves and complete exclusion of tumor in the internal auditory canal may be difficult with MR, especially in imperfectly positioned patients. MR studies of the temporal bones in patients and in normal volunteers positioned non-rotated or canted were correlated with corresponding cryomicrotomic sections. Especially in axial images, oblique sectioning of cranial nerves VII and VIII may cause difficulty in identifying individual nerves. A combination of axial and coronal short TR and TE images can be used to confidently exclude intracanalicular tumor in most cases. (orig.)

  4. Avaliação da espessura da camada de fibras nervosas da retina e mácula em pacientes com ambliopia Thickness of the retinal nerve fiber layer, macular thickness, in patients with amblyopia

    Directory of Open Access Journals (Sweden)

    Juliana Mitre

    2010-02-01

    Full Text Available OBJETIVO: Avaliar a espessura da camada de fibras nervosas da retina em olhos amblíopes e comparar com olhos normais e certificar se há correlação com a redução da acuidade visual. Além disso, este estudo se propõe avaliar a eficácia e eficiência em uma série de casos do protótipo de um equipamento nacional de magnificação para leitura. MÉTODOS: Participaram deste estudo 30 pacientes na faixa etária entre 9 e 80 anos (17 do sexo masculino. Foi desenvolvido um aparelho portátil, patenteado pela Unifesp (PI#020050145260, com um sistema de captura de imagens acoplado a um monitor de 5,6 polegadas proporcionando um aumento de 15 x. Foram analisadas a eficácia da acuidade visual e a eficiência de leitura após a utilização do protótipo proposto. RESULTADOS: Seis pacientes (20% apresentaram AV 8M, 12 pacientes (40% apresentaram AV 6M, 7 pacientes (23,3% apresentaram 5 M, 5 pacientes (16,7% apresentaram 4M. A média de acuidade visual antes da utilização do SLP medida pela tabela LHNV-1 logMAR foi de 5,75M e após a utilização 100% dos pacientes atingiram a eficácia de AV J1. CONCLUSÃO: O protótipo do SLP mostrou-se um recurso alternativo no processo de inclusão social das pessoas com baixa visão com diferentes níveis de resíduo visual. Também pode proporcionar incentivo psicológico, permitir conforto, mobilidade e independência àqueles que necessitam de uma leitura mais prolongada e maior distância de trabalho.OBJECTIVE: To compare the thickness of the retinal nerve fiber layer (RNFLand the macular thickness of the amblyopic eye with those of the non-amblyopic eye in patients with unilateral amblyopia using optical coherence tomography (OCT. METHODS: OCT was performed for13 patients with unilateral amblyopia who had no neurologic disease. Nine male andfour female patients, whose ages ranged from 23 to 63 years, were enrolled in the study. The RNFL thickness average analysis program was used to evaluate mean

  5. Fiber webs

    Science.gov (United States)

    Roger M. Rowell; James S. Han; Von L. Byrd

    2005-01-01

    Wood fibers can be used to produce a wide variety of low-density three-dimensional webs, mats, and fiber-molded products. Short wood fibers blended with long fibers can be formed into flexible fiber mats, which can be made by physical entanglement, nonwoven needling, or thermoplastic fiber melt matrix technologies. The most common types of flexible mats are carded, air...

  6. Optic Nerve Pit

    Science.gov (United States)

    ... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Optic Nerve Pit What is optic nerve pit? An optic nerve pit is a ... may be seen in both eyes. How is optic pit diagnosed? If the pit is not affecting ...

  7. Diagnostic nerve ultrasonography

    International Nuclear Information System (INIS)

    Baeumer, T.; Grimm, A.; Schelle, T.

    2017-01-01

    For the diagnostics of nerve lesions an imaging method is necessary to visualize peripheral nerves and their surrounding structures for an etiological classification. Clinical neurological and electrophysiological investigations provide functional information about nerve lesions. The information provided by a standard magnetic resonance imaging (MRI) examination is inadequate for peripheral nerve diagnostics; however, MRI neurography is suitable but on the other hand a resource and time-consuming method. Using ultrasonography for peripheral nerve diagnostics. With ultrasonography reliable diagnostics of entrapment neuropathies and traumatic nerve lesions are possible. The use of ultrasonography for neuropathies shows that a differentiation between different forms is possible. Nerve ultrasonography is an established diagnostic tool. In addition to the clinical examination and clinical electrophysiology, structural information can be obtained, which results in a clear improvement in the diagnostics. Ultrasonography has become an integral part of the diagnostic work-up of peripheral nerve lesions in neurophysiological departments. Nerve ultrasonography is recommended for the diagnostic work-up of peripheral nerve lesions in addition to clinical and electrophysiological investigations. It should be used in the clinical work-up of entrapment neuropathies, traumatic nerve lesions and spacy-occupying lesions of nerves. (orig.) [de

  8. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Lihua [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Center of Molecular Medicine, School of Medicine, Hubei University of Arts and Sciences, Xiangyang 441053 (China); Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Wang, Xiong; Huselstein, Celine [Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), UMR 7365 CNRS – Université de Lorraine, Biopôle, 54500 Vandoeuvre-lès-Nancy (France); Chen, Yun, E-mail: yunchen@whu.edu.cn [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China)

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  9. Rapid effects of hearing song on catecholaminergic activity in the songbird auditory pathway.

    Directory of Open Access Journals (Sweden)

    Lisa L Matragrano

    Full Text Available Catecholaminergic (CA neurons innervate sensory areas and affect the processing of sensory signals. For example, in birds, CA fibers innervate the auditory pathway at each level, including the midbrain, thalamus, and forebrain. We have shown previously that in female European starlings, CA activity in the auditory forebrain can be enhanced by exposure to attractive male song for one week. It is not known, however, whether hearing song can initiate that activity more rapidly. Here, we exposed estrogen-primed, female white-throated sparrows to conspecific male song and looked for evidence of rapid synthesis of catecholamines in auditory areas. In one hemisphere of the brain, we used immunohistochemistry to detect the phosphorylation of tyrosine hydroxylase (TH, a rate-limiting enzyme in the CA synthetic pathway. We found that immunoreactivity for TH phosphorylated at serine 40 increased dramatically in the auditory forebrain, but not the auditory thalamus and midbrain, after 15 min of song exposure. In the other hemisphere, we used high pressure liquid chromatography to measure catecholamines and their metabolites. We found that two dopamine metabolites, dihydroxyphenylacetic acid and homovanillic acid, increased in the auditory forebrain but not the auditory midbrain after 30 min of exposure to conspecific song. Our results are consistent with the hypothesis that exposure to a behaviorally relevant auditory stimulus rapidly induces CA activity, which may play a role in auditory responses.

  10. Reprodutibilidade do exame de medida da camada de fibras nervosas da retina por meio da polarimetria de varredura a laser Reproducibility of retinal nerve fiber layer measurement by scanning laser polarimetry

    Directory of Open Access Journals (Sweden)

    Fernanda Bon Duarte

    1999-10-01

    ,02, nferior/temporal (p = 0,03 e temporal/nasal (p = 0,007 e superior/inferior (p = 0,037 e para as médias de espessura nos quadrantes inferior (p = 0,04 e temporal (p = 0,003. Conclusões: A análise dos dados indica ótima reprodutibilidade do exame intra-observador, e na avaliação inter-observador os melhores resultados de reprodutibilidade são obtidos quando a média das imagens fornecida pelo programa do equipamento é empregada.Purpose: To analyze the intra- and inter-observer reprodu-cibility of retinal fiber layer measurements. Methods: Twenty-six normal eyes underwent retinal nerve fiber layer thickness measurements with the GDx scanning system. Three images of each eye were taken by three different observers. For each case, each observer was asked to choose the best image and also to use the mean of the three images for each case. Comparisons were made using the best image and also the mean image provided by the software. The mean thickness values in each quadrant and their ratios were compared using Friedman rank analysis of variance. Results: The comparison of results obtained from the three images taken by the same observer (intraobserver reprodu-tibility did not show any statistically significant difference. The analysis of the data by the R (resident, T (technician and G (ophthalmologist specialized in glaucoma observers revealed respective-ly: pR( S = 0.89; I = 0.24; T = 0.89; N = 0.30, pT( S = 0.76; I = 0.70; T = 0.22; N = 0.63, and pG( S = 0.48; I = 0.89; T = 0.30; N = 0.89. Regarding the isolated values (superior, inferior, temporal and nasal, the analysis of the results considering the values obtained from the mean image did not reveal a statistically significant difference between the three investigators. But when relationships were considered a statistically significant difference was observed regarding the superior/inferior ratio (p S/I = 0.037. Statistically significant differences were detected when considering the best image. Inferior and

  11. Intraoperative cranial nerve monitoring.

    Science.gov (United States)

    Harper, C Michel

    2004-03-01

    The purpose of intraoperative monitoring is to preserve function and prevent injury to the nervous system at a time when clinical examination is not possible. Cranial nerves are delicate structures and are susceptible to damage by mechanical trauma or ischemia during intracranial and extracranial surgery. A number of reliable electrodiagnostic techniques, including nerve conduction studies, electromyography, and the recording of evoked potentials have been adapted to the study of cranial nerve function during surgery. A growing body of evidence supports the utility of intraoperative monitoring of cranial nerve nerves during selected surgical procedures.

  12. [Morphology research of the rat sciatic nerve bridged by collage-heparin sulfate scaffold].

    Science.gov (United States)

    Wang, Shu-sen; Hu, Yun-yu; Luo, Zhuo-jing; Chen, Liang-wei; Liu, Hui-ling; Meng, Guo-lin; Lü, Rong; Xu, Xin-zhi

    2005-04-15

    To observe the treating effect of collage-heparin sulfate after the 10 mm rat sciatic nerve defect was bridged by it. A new kind of nervous tissue engineering scaffold was produced by freeze-drying technique from collagen-heparin sulfate. Thirty-two SD rats were randomly divided into A, B, C and D groups. Sciatic nerve defect in group A was bridged by collagen-heparin sulfate. In group B, sciatic nerve was bridged by auto-nerve transplantation. Group C was the blank control group. Animals in group D were normal. And 10 mm sciatic nerve defect was bridged in the experiment. Thirty-six weeks after the operation, the experimental animals were detected by HRP labeled retrograde trace, HE staining, toluidine staining, silvering staining, S100, GAP-43 and NF immunohistological staining, MBP immunofluorescence staining and transmission electron microscope to observe the nerve regeneration inducing effect of this new scaffold. Nine months after operation, the collage-heparin sulfate scaffold was replaced by newly regenerated nerve. The number of HRP labeled spinal cord anterior horn cells and the area of sensation nerve fiber at the posterior horn were similar with that was repaired by auto-nerve. GAP-43, NF and S100 labeled regenerated nerve fiber had passed the total scaffold and entered the distal terminal. The regenerated nerve fibers were paralleled, lineage arranged, coincide with the prearranged regenerating "channel" in the collagen-heparin sulfate scaffold. MBP immunofluorescence staining also proved that the newly regenerated nerve fiber could be ensheathed. In the experimental group, the area of myelinated nerve fiber and the thickness of the myelin sheath had no obvious difference with that of the group repaired by auto-nerve, except that the density of the regenerated myelinated sheath fiber was lower than that of the control group. Nervous tissue engineering scaffold produced by collagen-heparin sulfate can guide the regeneration of nerve fibers. The nerve

  13. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  14. Development of the auditory system

    Science.gov (United States)

    Litovsky, Ruth

    2015-01-01

    Auditory development involves changes in the peripheral and central nervous system along the auditory pathways, and these occur naturally, and in response to stimulation. Human development occurs along a trajectory that can last decades, and is studied using behavioral psychophysics, as well as physiologic measurements with neural imaging. The auditory system constructs a perceptual space that takes information from objects and groups, segregates sounds, and provides meaning and access to communication tools such as language. Auditory signals are processed in a series of analysis stages, from peripheral to central. Coding of information has been studied for features of sound, including frequency, intensity, loudness, and location, in quiet and in the presence of maskers. In the latter case, the ability of the auditory system to perform an analysis of the scene becomes highly relevant. While some basic abilities are well developed at birth, there is a clear prolonged maturation of auditory development well into the teenage years. Maturation involves auditory pathways. However, non-auditory changes (attention, memory, cognition) play an important role in auditory development. The ability of the auditory system to adapt in response to novel stimuli is a key feature of development throughout the nervous system, known as neural plasticity. PMID:25726262

  15. Animal models for auditory streaming

    Science.gov (United States)

    Itatani, Naoya

    2017-01-01