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Sample records for monosynaptic stretch reflex

  1. EFFECT OF NEURAL MOBILIZATION ON MONOSYNAPTIC REFLEX – A PRE TEST POST TEST EXPERIMENTAL DESIGN

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    Vipin Kumar

    2013-08-01

    Full Text Available Background:Neural mobilization techniques leads tofacilitation of nerve gliding, reduction of nerve adher-ence, dispersion of noxious fluids, increased neural vascularity and improvement of axoplasmic flow.It haspronounced effects on monosynaptic H-reflex, which is an electrically induced reflex analogous to mechani-cally induced spinal stretch reflex. Thus, it is a reliable tool for the assessment of muscle tone through theexcitability of AMNs.Materials and Methods:The study was carried out with30 male and female subjects fromMMIPR, MM University Mullana. H-reflex was taken before and after neural mobilization.Results:Significanteffects on monosynaptic H-reflex were shown after neural mobilization with a mean difference of decrease inH-reflex latency (28.43±2.13 ms to 26.91±1.99 ms; t-value 13.24 and increase in H-reflex amplitude(4.27±2.18mv to 5.25±2.50 mv; t-value -5.13 and increase in H/M ratio (0.42±0.21 to 0.52±0.25; t-value -5.22.Conclusion:Neural mobilization has direct effect on nerve conduction as measured by electrophysiologicaltesting, thereby providing evidence to include neural mobilizations as an intervention in altered neurodynamicsof the peripheral nerves.

  2. Neural effects of muscle stretching on the spinal reflexes in multiple lower-limb muscles.

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    Masugi, Yohei; Obata, Hiroki; Inoue, Daisuke; Kawashima, Noritaka; Nakazawa, Kimitaka

    2017-01-01

    While previous studies have shown that muscle stretching suppresses monosynaptic spinal reflex excitability in stretched muscles, its effects on non-stretched muscles is still largely unknown. The purpose of this study was to examine the effects of muscle stretching on monosynaptic spinal reflex in non-stretched muscles. Ten healthy male subjects participated in this study. Muscle stretching of the right triceps surae muscle was performed using a motor torque device for 1 minute. Three different dorsiflexion torques (at approximately 5, 10, and 15 Nm) were applied during muscle stretching. Spinal reflexes evoked by transcutaneous spinal cord stimulation were recorded in both the lower-limb muscles before, during, and at 0 and 5 min following muscle stretching. The amplitudes of the spinal reflexes in both the stretched and non-stretched muscles in the right (ipsilateral) leg were smaller during stretching compared to before, and at 0 and 5 min after stretching. Furthermore, the degree of reduction in the amplitude of the spinal reflexes in the right (ipsilateral) leg muscles increased significantly as the dorsiflexion torque (i.e., stretching of the right triceps surae muscles) increased. In contrast, reduction in the amplitude of the spinal reflexes with increasing dorsiflexion torque was not seen in the left (contralateral) leg muscles. Our results clearly indicate that muscle stretching has inhibitory effects on monosynaptic spinal reflexes, not only in stretched muscles, but also in non-stretched muscles of the ipsilateral leg.

  3. Spindle activity and monosynaptic reflex excitability during foreperiod.

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    Gerilovsky, L; Struppler, A; Altmann, H; Velho, F

    1983-11-01

    Healthy volunteers were instructed to perform an isometric plantar foot flexion as quickly as possible after a foreperiod (FP) of 1000 msec defined by two clicks (warning signal (WS) and response signal (RS). In 6 volunteers the H reflex was evoked in triceps surae muscle and recorded by surface electrodes (stimulus intensity 30% of maximum). The H reflex was elicited at WS and RS as well as during FP at intervals of 100 msec. H reflex amplitudes were taken as a sign of monosynaptic reflex excitability (MSRE). Amplitudes during FP were compared with the average control values at rest. Relaxation of lower limb muscles before and during FP was controlled by EMG. MSRE was increased in the first part of FP with a maximum at 300 msec after WS and decreased in the second part, with a minimum at 800 msec after WS. In a second series of experiments, in 10 volunteers, single fiber activity from primary muscle spindle afferents was recorded with tungsten electrodes from deep peroneal nerve (6 records) and from tibial nerve (3 records). The activity of primary spindle afferents before and during the FP was calculated by instantaneous discharge frequency and histograms of spike distribution. The EMG was taken from sural triceps and anterior tibial muscles with needle electrodes; a mechanogram of tendon deflection was taken by an appropriate strain gauge. In 5 primary afferents without spontaneous activity at rest and during FP, discharge started with a delay of 10-15 msec after the onset of EMG activity during the motor reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Soleus stretch reflex during cycling

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    Grey, Michael James; Pierce, C. W.; Milner, T. E.

    2001-01-01

    The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

  5. Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord.

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    Hofstoetter, Ursula S; Danner, Simon M; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

    2015-07-01

    In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22-60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural stimulation in eight motor-complete spinal cord-injured individuals. Periodic amplitude modulation of at least 20 successive responses occurred in 31.4% of all available data sets with stimulation frequency set at 5-26 Hz, with highest prevalence at 16 Hz. It could be evoked in a single muscle group only but was more strongly expressed and consistent when occurring in pairs of antagonists or in the same muscle group bilaterally. Latencies and waveforms of the modulated reflexes corresponded to those of the unmodulated, monosynaptic responses to 2-Hz stimulation. We suggest that the cyclical changes of reflex excitability resulted from the interaction of facilitatory and inhibitory mechanisms emerging after specific delays and with distinct durations, including postactivation depression, recurrent inhibition and facilitation, as well as reafferent feedback activation. The emergence of large responses within the patterns at a rate of 5.5/s or 8/s may further suggest the entrainment of spinal mechanisms as involved in clonus. The study demonstrates that the human lumbosacral spinal cord can organize a simple form of rhythmicity through the repetitive activation of spinal reflex circuits. Copyright © 2015 the American Physiological Society.

  6. Tonically Active α5GABAA Receptors Reduce Motoneuron Excitability and Decrease the Monosynaptic Reflex

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    Martha Canto-Bustos

    2017-09-01

    Full Text Available Motoneurons, the final common path of the Central Nervous System (CNS, are under a complex control of its excitability in order to precisely translate the interneuronal pattern of activity into skeletal muscle contraction and relaxation. To fulfill this relevant function, motoneurons are provided with a vast repertoire of receptors and channels, including the extrasynaptic GABAA receptors which have been poorly investigated. Here, we confirmed that extrasynaptic α5 subunit-containing GABAA receptors localize with choline acetyltransferase (ChAT positive cells, suggesting that these receptors are expressed in turtle motoneurons as previously reported in rodents. In these cells, α5GABAA receptors are activated by ambient GABA, producing a tonic shunt that reduces motoneurons’ membrane resistance and affects their action potential firing properties. In addition, α5GABAA receptors shunted the synaptic excitatory inputs depressing the monosynaptic reflex (MSR induced by activation of primary afferents. Therefore, our results suggest that α5GABAA receptors may play a relevant physiological role in motor control.

  7. Fluctuations of excitability in the monosynaptic reflex pathway to lumbar motoneurons in the cat.

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    Gossard, J P; Floeter, M K; Kawai, Y; Burke, R E; Chang, T; Schiff, S J

    1994-09-01

    1. It is well known that the amplitude of successive monosynaptic reflexes (MSR), elicited by afferent stimuli of constant strength, fluctuate from trial to trial. Previous evidence suggests that such excitability fluctuations within the motor pool can be introduced either pre- and/or postsynaptically. Using unanesthetized decerebrate or decerebrate/spinal cats, we attempted to evaluate the relative importance of pre- and postsynaptic mechanisms to MSR variability and the potential contribution of changes in the identities of responding motoneurons to such variability. 2. Comparisons between the MSR amplitude, measured in a severed ventral root, and the probability of firing of up to three individual motoneurons in fine filaments teased from the same root, confirmed that both correlated and uncorrelated fluctuations of motoneuron excitability are involved in MSR variability. Linear regression analysis from concurrent intracellular recordings from homonymous motoneurons showed that the MSR fluctuations were correlated with the variations in membrane potential baseline, as well as with the fluctuations in the monosynaptic excitatory postsynaptic potential peak amplitude. In all 11 cases tested, the former correlation was stronger than the latter. 3. Stimulation of the caudal cutaneous sural nerve (CCS) was used to alter the postsynaptic potential background on which triceps surae (GS) MSRs were generated. The interval chosen between CCS conditioning and the GS stimulation excluded the involvement of presynaptic inhibition. When conditioned by preceding CCS stimulation, GS population MSRs generally (8/9 cases tested) increased in amplitude without much change in their overall variance. However, the individual motoneurons that contributed to the population responses did show changes in both relative excitability and in the uncorrelated component of their response variance. About half of the concurrently recorded motoneurons (6/13) showed a decrease in relative

  8. The stretch reflex and the contributions of C David Marsden

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    Kalyan B Bhattacharyya

    2017-01-01

    Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  9. Method for recording spinal reflexes in mice: effects of thyrotropin-releasing hormone, DOI, tolperisone and baclofen on monosynaptic spinal reflex potentials.

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    Okada, H; Honda, M; Ono, H

    2001-05-01

    Mice were used to record the spinal reflex potentials and to examine the effects of some drugs upon them. In anesthetized mice, laminectomy was performed in the lumbo-sacral region, and monosynaptic reflex potential (MSR) and polysynaptic reflex potential were recorded from the L5 ventral root after stimulation of the L5 dorsal root. Thyrotropin-releasing hormone (TRH) and 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI) produced transient and long-lasting increases in the MSR amplitude, respectively. Tolperisone hydrochloride and baclofen produced transient and long-lasting MSR depressions, respectively. These results show that mice can be used to record spinal reflex potentials, and that it may be possible to study the spinal cord function of mutant and knockout mice using this method.

  10. Neurophysiological methods for the assessment of spasticity: the Hoffmann reflex, the tendon reflex, and the stretch reflex

    NARCIS (Netherlands)

    Voerman, Gerlienke; Gregoric, M.; Hermens, Hermanus J.

    PURPOSE: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). METHOD: A

  11. Effects of stimulation of group I afferents from flexor muscles on heterosynaptic facilitation of monosynaptic reflexes produced by Ia and descending inputs: a test for presynaptic inhibition.

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    Rudomin, P; Jiménez, I; Enriquez, M

    1991-01-01

    1. In the chloralose anesthetized cat, conditioning stimulation of group I flexor afferents depresses the monosynaptic potentials generated by Ia afferents in single spinal motoneurons or in populations of motoneurons without affecting the monosynaptic potentials produced by stimulation of descending fibers in the ipsilateral ventromedial fasciculus (VMF). 2. Heterosynaptic facilitation of monosynaptic reflexes was used to test changes in the presynaptic effectiveness of excitatory inputs with direct connections with motoneurons. We found that the heterosynaptic facilitation of Ia origin was reduced by conditioning stimulation of group I afferents from flexors, without affecting the heterosynaptic facilitation produced by stimulation of the VMF. 3. These results confirm and expand previous observations showing that the synaptic effectiveness of descending fibers synapsing with motoneurons is not subjected to a presynaptic control mechanism of the type acting on Ia fiber terminals, and provide further basis for the use of changes in heterosynaptic facilitation of monosynaptic reflexes of Ia origin as an estimate of changes in presynaptic inhibition of Ia fibers (Hultborn et al. 1987a).

  12. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

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    Lizeth H Sloot

    Full Text Available Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms. Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally

  13. Stretch reflex instability compared in three different human muscles.

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    Durbaba, R; Taylor, A; Manu, C A; Buonajuti, M

    2005-06-01

    The possibility of causing instability in the stretch reflex has been examined in three different human muscles: biceps, first dorsal interosseous (FDI) of the hand and digastric. Tremor recorded as fluctuation of isometric force was compared with that occurring during contraction against a spring load. The spring compliance was selected to make the natural frequency of the part in each case appropriate for oscillations in the short latency stretch reflex. A computer model of the whole system was used to predict the frequency at which oscillations should be expected and to estimate the reflex gain required in each case to cause sustained oscillations. Estimates were computed of the autospectra of the force records and of the rectified surface EMG signals and of the coherence functions. Normal subjects showed no evidence of a distinct spectral peak during isometric recording from any of the three muscles. However, in anisometric conditions regular oscillations in force occurred in biceps, but not in FDI or digastric. The oscillations in biceps at 8-9 Hz were accompanied by similar oscillations in the EMG which were highly coherent with the force signal. The results are consistent with the presence of a strong segmental stretch reflex effect in biceps and weak or absent reflex in FDI. Digastric is known to contain no muscle spindles and therefore to lack a stretch reflex. In two subjects who volunteered that they had more tremor than normal, but had no known neurological abnormality, there was a distinct peak in the force spectrum at 8-9 Hz in biceps and FDI in isometric conditions with coherent EMG activity. The peak increased in size in anisometric conditions in biceps but not in FDI. This component appears to be of central rather than of reflex origin. No equivalent component was found in digastric records. The results are discussed in relation to the possible role of the short latency stretch reflex in the genesis of physiological tremor in different muscles.

  14. Bisphenol A depresses monosynaptic and polysynaptic reflexes in neonatal rat spinal cord in vitro involving estrogen receptor-dependent NO-mediated mechanisms.

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    Pandey, A K; Deshpande, S B

    2015-03-19

    Bisphenol A (BPA), a toxic chemical from plastics, is known to produce locomotor abnormalities which may imply the alteration in synaptic activity at Ia-α motoneuron synapse also. However the effect of BPA on this synapse is not known. Therefore, this study was undertaken to examine the effect of BPA on reflexes originating at Ia-α motoneuron synapse in the spinal cord. The experiments were performed on isolated hemisected spinal cords from 4 to 6d rats. Stimulation of a dorsal root evoked segmental monosynaptic (MSR) and polysynaptic (PSR) reflex potentials in the corresponding ventral root. Nitrite content (indicator of NO activity) of cords was estimated in the presence of BPA with/without antagonists. Superfusion of BPA (3-100μM) depressed the reflexes in a concentration- and time-dependent manner. The depression was ∼20, ∼50 and ∼70% at 10, 30 and 100μM of BPA, respectively. The 50% depression occurred around 15min at 30μM of BPA. Pretreatment with estrogen receptor (ERα) antagonist, tamoxifen, blocked the BPA-induced depression of reflexes, whereas, 17β-estradiol, ER agonist, did not depress the reflexes even up to 10μM. Further, pretreatment with Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME) or hemoglobin (Hb) blocked the BPA-induced depression of spinal reflexes. Nitric oxide (NO) donor sodium-nitroprusside depressed the MSR and PSR in a concentration-dependent manner. The nitrite concentration of the cords exposed to BPA was 733μM/gm of tissue (three times the saline group). Pretreatment with tamoxifen/l-NAME/Hb blocked the BPA-induced increase of nitrite levels. The present observations indicate that BPA depressed spinal synaptic transmission through ERα-dependent NO-mediated mechanisms. The altered synaptic activity may implicate for neurobehavioral locomotor abnormalities after exposure to BPA. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. Short-Term Plasticity in a Monosynaptic Reflex Pathway to Forearm Muscles after Continuous Robot-Assisted Passive Stepping.

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    Nakajima, Tsuyoshi; Kamibayashi, Kiyotaka; Kitamura, Taku; Komiyama, Tomoyoshi; Zehr, E Paul; Nakazawa, Kimitaka

    2016-01-01

    Both active and passive rhythmic limb movements reduce the amplitude of spinal cord Hoffmann (H-) reflexes in muscles of moving and distant limbs. This could have clinical utility in remote modulation of the pathologically hyperactive reflexes found in spasticity after stroke or spinal cord injury. However, such clinical translation is currently hampered by a lack of critical information regarding the minimum or effective duration of passive movement needed for modulating spinal cord excitability. We therefore investigated the H-reflex modulation in the flexor carpi radialis (FCR) muscle during and after various durations (5, 10, 15, and 30 min) of passive stepping in 11 neurologically normal subjects. Passive stepping was performed by a robotic gait trainer system (Lokomat(®)) while a single pulse of electrical stimulation to the median nerve elicited H-reflexes in the FCR. The amplitude of the FCR H-reflex was significantly suppressed during passive stepping. Although 30 min of passive stepping was sufficient to elicit a persistent H-reflex suppression that lasted up to 15 min, 5 min of passive stepping was not. The duration of H-reflex suppression correlated with that of the stepping. These findings suggest that the accumulation of stepping-related afferent feedback from the leg plays a role in generating short-term interlimb plasticity in the circuitry of the FCR H-reflex.

  16. Short-term plasticity in a monosynaptic reflex pathway to forearm muscles after continuous robot-assisted passive stepping

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    Tsuyoshi Nakajima

    2016-07-01

    Full Text Available Both active and passive rhythmic limb movements reduce the amplitude of spinal cord Hoffmann (H- reflexes in muscles of moving and distant limbs. This could have clinical utility in remote modulation of the pathologically hyperactive reflexes found in spasticity after stroke or spinal cord injury. However, such clinical translation is currently hampered by a lack of critical information regarding the minimum or effective duration of passive movement needed for modulating spinal cord excitability. We therefore investigated the H-reflex modulation in the flexor carpi radialis (FCR muscle during and after various durations (5, 10, 15, and 30 min of passive stepping in 11 neurologically normal subjects. Passive stepping was performed by a robotic gait trainer system (Lokomat® while a single pulse of electrical stimulation to the median nerve elicited H-reflexes in the FCR. The amplitude of the FCR H-reflex was significantly suppressed during passive stepping. Although 30 minutes of passive stepping was sufficient to elicit a persistent H-reflex suppression that lasted up to 15 minutes, 5 minutes of passive stepping was not. The duration of H-reflex suppression correlated with that of the stepping. These findings suggest that the accumulation of stepping-related afferent feedback from the leg plays a role in generating short-term interlimb plasticity in the circuitry of the FCR H-reflex.

  17. Stretch sensitive reflexes as an adaptive mechanism for maintaining limb stability

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    Shemmell, Jonathan; Krutky, Matthew A.; Perreault, Eric J.

    2010-01-01

    The often studied stretch reflex is fundamental to the involuntary control of posture and movement. Nevertheless, there remains controversy regarding its functional role. Many studies have demonstrated that stretch reflexes can be modulated in a task appropriate manner. This review focuses on modulation of the long latency stretch reflex, thought to be mediated, at least in part, by supraspinal pathways. For example, this component of the stretch reflex increases in magnitude during interactions with compliant environments, relative to the sensitivity during interactions with rigid environments. This suggests that reflex sensitivity increases to augment limb stability when that stability is not provided by the environment. However, not all results support the stabilizing role of stretch reflexes. Some studies have demonstrated that involuntary responses within the time period corresponding to the long latency reflex can destabilize limb posture. We propose that this debate stems from the fact that multiple perturbation-sensitive pathways can contribute to the long latency stretch reflex and that these pathways have separate functional roles. The presented studies suggest that neural activity occurring within the period normally ascribed to the long latency stretch reflex is highly adaptable to current task demands and possibly should be considered more intelligent than “reflexive.” PMID:20434396

  18. A task dependent change in the medium latency component of the soleus stretch reflex

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    Grey, Michael James; Larsen, Birgit; Sinkjær, Thomas

    2002-01-01

    In comparison to the H-reflex, the task dependency of the human stretch reflex during locomotive and postural tasks has not received a great deal of attention in the literature. The few studies on reflex task dependency that have been performed to date have concentrated on either the group Ia...

  19. Effects of contraction intensity on muscle fascicle and stretch reflex behavior in the human triceps surae.

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    Cronin, Neil J; Peltonen, Jussi; Ishikawa, Masaki; Komi, Paavo V; Avela, Janne; Sinkjaer, Thomas; Voigt, Michael

    2008-07-01

    The aims of this study were to examine changes in the distribution of a stretch to the muscle fascicles with changes in contraction intensity in the human triceps surae and to relate fascicle stretch responses to short-latency stretch reflex behavior. Thirteen healthy subjects were seated in an ankle ergometer, and dorsiflexion stretches (8 degrees ; 250 degrees /s) were applied to the triceps surae at different moment levels (0-100% of maximal voluntary contraction). Surface EMG was recorded in the medial gastrocnemius, soleus, and tibialis anterior muscles, and ultrasound was used to measure medial gastrocnemius and soleus fascicle lengths. At low forces, reflex amplitudes increased despite a lack of change or even a decrease in fascicle stretch velocities. At high forces, lower fascicle stretch velocities coincided with smaller stretch reflexes. The results revealed a decline in fascicle stretch velocity of over 50% between passive conditions and maximal force levels in the major muscles of the triceps surae. This is likely to be an important factor related to the decline in stretch reflex amplitudes at high forces. Because short-latency stretch reflexes contribute to force production and stiffness regulation of human muscle fibers, a reduction in afferent feedback from muscle spindles could decrease the efficacy of human movements involving the triceps surae, particularly where high force production is required.

  20. Tibialis anterior stretch reflex in early stance is suppressed by repetitive transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Zuur, Abraham T; Christensen, Mark Schram; Sinkjær, Thomas

    2009-01-01

    Abstract A rapid plantar flexion perturbation in the early stance phase of walking elicits a large stretch reflex in tibialis anterior (TA). In this study we use repetitive Transcranial Magnetic Stimulation (rTMS) to test if this response is mediated through a transcortical pathway. TA stretch...

  1. An Intelligent Computerized Stretch Reflex Measurement System For Clinical And Investigative Neurology

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    Flanagan, P. M.; Chutkow, J. G.; Riggs, M. T.; Cristiano, V. D.

    1987-05-01

    We describe the design of a reliable, user-friendly preprototype system for quantifying the tendon stretch reflexes in humans and large mammals. A hand-held, instrumented reflex gun, the impactor of which contains a single force sensor, interfaces with a computer. The resulting test system can deliver sequences of reproducible stimuli at graded intensities and adjustable durations to a muscle's tendon ("tendon taps"), measure the impacting force of each tap, and record the subsequent reflex muscle contraction from the same tendon -- all automatically. The parameters of the reflex muscle contraction include latency; mechanical threshold; and peak time, peak magnitude, and settling time. The results of clinical tests presented in this paper illustrate the system's potential usefulness in detecting neurologic dysfunction affecting the tendon stretch reflexes, in documenting the course of neurologic illnesses and their response to therapy, and in clinical and laboratory neurologic research.

  2. Altered activation patterns by triceps surae stretch reflex pathways in acute and chronic spinal cord injury.

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    Frigon, Alain; Johnson, Michael D; Heckman, C J

    2011-10-01

    Spinal reflexes are modified by spinal cord injury (SCI) due the loss of excitatory inputs from supraspinal structures and changes within the spinal cord. The stretch reflex is one of the simplest pathways of the central nervous system and was used presently to evaluate how inputs from primary and secondary muscle spindles interact with spinal circuits before and after spinal transection (i.e., spinalization) in 12 adult decerebrate cats. Seven cats were spinalized and allowed to recover for 1 mo (i.e., chronic spinal state), whereas 5 cats were evaluated before (i.e., intact state) and after acute spinalization (i.e., acute spinal state). Stretch reflexes were evoked by stretching the left triceps surae (TS) muscles. The force evoked by TS muscles was recorded along with the activity of several hindlimb muscles. Stretch reflexes were abolished in the acute spinal state due to an inability to activate TS muscles, such as soleus (Sol) and lateral gastrocnemius (LG). In chronic spinal cats, reflex force had partly recovered but Sol and LG activity remained considerably depressed, despite the fact that injecting clonidine could recruit these muscles during locomotor-like activity. In contrast, other muscles not recruited in the intact state, most notably semitendinosus and sartorius, were strongly activated by stretching TS muscles in chronic spinal cats. Therefore, stretch reflex pathways from TS muscles to multiple hindlimb muscles undergo functional reorganization following spinalization, both acute and chronic. Altered activation patterns by stretch reflex pathways could explain some sensorimotor deficits observed during locomotion and postural corrections after SCI.

  3. Massage and stretching reduce spinal reflex excitability without affecting twitch contractile properties.

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    Behm, David G; Peach, Ashley; Maddigan, Meaghan; Aboodarda, Saied Jalal; DiSanto, Mario C; Button, Duane C; Maffiuletti, Nicola A

    2013-10-01

    Both stretching and massage can increase range of motion. Whereas the stretching-induced increases in ROM have been attributed to changes in neural and muscle responses, there is no literature investigating the ROM mechanisms underlying the interaction of stretch and massage. The objective of this paper was to evaluate changes in neural and evoked muscle responses with two types of massage and static stretching. With this repeated measures design, 30s of plantar flexors musculotendinous junction (MTJ) and tapotement (TAP) massage were implemented either with or without 1min of concurrent stretching as well as a control condition. Measures included the soleus maximum H-reflex/M-wave (H/M) ratio, as well as electromechanical delay (EMD), and evoked contractile properties of the triceps surae. With the exception of EMD, massage and stretch did not significantly alter triceps surae evoked contractile properties. Massage with and without stretching decreased the soleus H/M ratio. Both TAP conditions provided greater H/M ratio depression than MTJ massage while the addition of stretch provided the greatest inhibition. Both massage types when combined with stretching increased the duration of the EMD. In conclusion, MTJ and TAP massage as well as stretching decreased spinal reflex excitability, with TAP providing the strongest suppression. While static stretching prolongs EMD, massage did not affect contractile properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Triceps surae stretch reflex modulation after a mechanically evoked ankle dorsiflexion during the swing phase of human running.

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    Scohier, Mikael; De Jaeger, Dominique; Schepens, Benedicte

    2014-10-01

    The purpose of this study was to mechanically evoke a triceps surae stretch reflex during the swing phase of running, to study its within-the-step phase dependency. Seven participants ran on a treadmill at 2.8 m·s-1 wearing an exoskeleton capable of evoking a sudden ankle dorsiflexion. We measured the electromyographic activity of the soleus, medial and lateral gastrocnemii just after the perturbation to evaluate the triceps surae stretch reflex. Similar perturbations were also delivered at rest. Our results showed that the stretch reflex was suppressed during the swing phase of running, except in late swing where a late reflex response was observed. At rest, all triceps surae muscles showed an early reflex response to stretch. Our findings suggest that the triceps surae short/medium-latency stretch reflex cannot be evoked during swing phase and thus cannot contribute to the control of the locomotor pattern after aperturbation during this phase.

  5. Is the long-latency stretch reflex in human masseter transcortical?

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    Pearce, Sophie L; Miles, Timothy S; Thompson, Philip D; Nordstrom, Michael A

    2003-06-01

    A long-latency stretch reflex (LLSR) has been described in the human masseter muscle, but its pathway remains uncertain. To investigate this, the excitability of corticomotoneuronal (CM) cells projecting to masseter motoneurons during the LLSR was assessed with transcranial magnetic stimulation (TMS). A facilitated response to TMS would be evidence of a LLSR pathway that traverses the motor cortex. Surface electromyogram electrodes were placed over the left or right masseter, and subjects ( n=10) bit on bars with their incisor teeth at 10% of maximal electromyographic activity (EMG). Servo-controlled displacements were imposed on the lower jaw to evoke a short- and long-latency stretch reflex in masseter. TMS intensity was just suprathreshold for a response in contralateral masseter. Trials consisted of: (1) stretch alone, (2) TMS alone, and (3) TMS with a preceding conditioning stretch at varied conditioning-testing (C-T) intervals chosen to combine TMS with the short-latency stretch reflex (3 ms, 5 ms) and the LLSR (23-41 ms). Masseter EMG was rectified and averaged. With TMS alone, mean (+/- SE) MEP area above baseline was 56+/-9%. The area of masseter MEPs above baseline in the C-T trials was calculated from each EMG average following subtraction of the response to stretch alone. Conditioning muscle stretch had no significant effect on masseter MEPs evoked by TMS with any C-T interval (ANOVA; P=0.90). In addition, subjects were unable to modify the SLSR or LLSR by voluntary command. It is concluded that the long-latency stretch reflex in the masseter does not involve the motor cortex and is not influenced by "motor set".

  6. Effects of postural threat on spinal stretch reflexes: evidence for increased muscle spindle sensitivity?

    Science.gov (United States)

    Horslen, Brian C; Murnaghan, Chantelle D; Inglis, J Timothy; Chua, Romeo; Carpenter, Mark G

    2013-08-01

    Standing balance is often threatened in everyday life. These threats typically involve scenarios in which either the likelihood or the consequence of falling is higher than normal. When cats are placed in these scenarios they respond by increasing the sensitivity of muscle spindles imbedded in the leg muscles, presumably to increase balance-relevant afferent information available to the nervous system. At present, it is unknown whether humans also respond to such postural threats by altering muscle spindle sensitivity. Here we present two studies that probed the effects of postural threat on spinal stretch reflexes. In study 1 we manipulated the threat associated with an increased consequence of a fall by having subjects stand at the edge of an elevated surface (3.2 m). In study 2 we manipulated the threat by increasing the likelihood of a fall by occasionally tilting the support surface on which subjects stood. In both scenarios we used Hoffmann (H) and tendon stretch (T) reflexes to probe the spinal stretch reflex circuit of the soleus muscle. We observed increased T-reflex amplitudes and unchanged H-reflex amplitudes in both threat scenarios. These results suggest that the synaptic state of the spinal stretch reflex is unaffected by postural threat and that therefore the muscle spindles activated in the T-reflexes must be more sensitive in the threatening conditions. We propose that this increase in sensitivity may function to satisfy the conflicting needs to restrict movement with threat, while maintaining a certain amount of sensory information related to postural control.

  7. Inhibition of the triceps surae stretch reflex by stimulation of the deep peroneal nerve in persons with spastic stroke

    NARCIS (Netherlands)

    Veltink, Peter H.; Ladouceur, Michel; Sinkjaer, Thomas

    2000-01-01

    Inhibition of the triceps surae stretch reflex by stimulation of the deep peroneal nerve in persons with spastic stroke. Arch Phys Med Rehabil 2000;81:1016-24. Objective: To reduce the triceps surae stretch reflex by electrical stimulation of the deep peroneal nerve. Design: Intervention study. Sett

  8. The influence of stretching and warm-up exercises on Achilles tendon reflex activity.

    Science.gov (United States)

    Rosenbaum, D; Hennig, E M

    1995-12-01

    The aim of this study was to investigate the acute effects of prior exercise (warm-up and stretching) on the electromyographic and force output of mechanically elicited triceps surae reflexes. Fifty male subjects performed eight reflex experiments under each of three successive conditions in one session: (1) no prior exercise, (2) after static stretching of the passive triceps surae (3 min) and (3) after a 10-min warm-up run on a treadmill. Tendon tap reflex force was elicited in the triceps surae of the right leg by means of a standardized reflex hammer and measured in a custom-built fixture. Electromyographic (EMG) signals were recorded with surface electrodes over the medial head of the gastrocnemius (G) and the soleus (S). Low coefficients of variation within subjects contrasted with high between-subject variations, indicating highly individual reflex characteristics. After stretching, reductions in the peak force (-5%; P running, the peak force reached the values obtained without prior exercise (-2%; N.S.), the force rise rate and half relaxation rate increased by 8 and 12%, respectively (P run had a more pronounced influence with regard to improved force development and a decreased EMG activity, which can be viewed as a performance-enhancing effect.

  9. One minute static stretch of plantar flexors transiently increases H reflex excitability and exerts no effect on corticospinal pathways.

    Science.gov (United States)

    Budini, Francesco; Gallasch, Eugen; Christova, Monica; Rafolt, Dietmar; Rauscher, Andreas Benedikt; Tilp, Markus

    2017-08-01

    What is the central question of this study? What mediates neural responses following static stretching, and how long do these influences last? What is the main finding and its importance? This study shows that 1 min of static stretching inhibits the tendon tap reflex and facilitates the H reflex without influencing motor-evoked potentials. The results indicate that at least two different mechanisms mediate neural responses after static stretching. The purpose of this study was to determine whether the neural responses observed after static stretching are mediated by sensitivity of muscle spindles, spinal excitability or cortical excitability and how long these influences last. Nineteen volunteers (25.7 ± 5.6 years old) were tested for the tendon tap reflex (T-reflex), H reflex and motor-evoked potentials on ankle flexors and extensors immediately, 5 and 10 min after 1 min static stretching applied at individual maximal ankle dorsiflexion, as well as immediately, 5 and 10 min after a control period of the same duration. Comparison of measurements collected immediately after stretching or control conditions revealed that the T-reflex was weaker after stretching than after control (-59.2% P = 0.000). The T-reflex showed a slow recovery rate within the first 150 s after stretching, but 5 min after the inhibition had disappeared. The H reflex increased immediately after stretching (+18.3%, P = 0.036), showed a quick tendency to recover and returned to control values within 5 min from stretching. Motor-evoked potentials were not affected by the procedure. These results suggest that 1 min of static stretching primarily decreases muscle spindle sensitivity and facilitates the H reflex, whereas effects on the motor cortex can be excluded. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

  10. Plantar flexor stretch reflex responses to whole body loading/unloading during human walking

    DEFF Research Database (Denmark)

    Grey, Michael James; van Doornik, Johannes; Sinkjær, Thomas

    2002-01-01

    was to investigate the contribution of load receptor feedback to the compensatory stretch reflex response. We examined the contribution of load receptor feedback to the magnitude of the short and medium latency components of the ankle plantar flexor stretch reflex responses following an unexpected dorsiflexion...... perturbation during human walking. Three body load conditions were investigated: normal body load, a 30% increase in body load, and a 30% decrease in body load. Healthy subjects walked on a treadmill at approximately 3.6 km/h with the left ankle attached to a portable stretching device. Dorsiflexion...... perturbations (8 degrees; 350-425 degrees/s) were generated during the late stance phase of gate (approximately 400 ms following heel contact). Electromyographic activity was recorded from the soleus, tibialis anterior, medial gastrocnemius, rectus femoris, and biceps femoris muscles using bipolar surface...

  11. Golgi tendon organ reflex inhibition following manually applied acute static stretching.

    Science.gov (United States)

    Miller, Kevin C; Burne, John A

    2014-01-01

    Golgi tendon organ disinhibition may contribute to exercise-associated muscle cramp (henceforth referred to as "cramps") genesis. Static stretching pre-exercise is prescribed to prevent cramps based on the assumption golgi tendon organ inhibition remains elevated post-stretching. We determined whether stretching increased gastrocnemius golgi tendon organ inhibition and, if so, the time course of this inhibition post-stretching. Twelve participants' dominant limb medial gastrocnemius inhibition was measured before, and at 1, 5, 10, 15 and 30 min after investigators applied three, 1-min duration stretches. Participants maintained voluntary contraction intensities of 5% of their maximum while the Achilles tendon was stimulated transcutaneously 50 times. Five-hundred millisecond epochs of raw electromyographic activity were band-pass filtered, full-wave rectified and averaged. An algorithm identified inhibitory points and calculated the area, maximum and duration of inhibition. Area of inhibition (F1,14 = 1.5, P = 0.25), maximum inhibition (F1,14 = 0.2, P = 0.72) and duration of inhibition (F1,14 = 1.5, P = 0.24) were unaffected by static stretching over the 30-min post-stretching period. If pre-stretching does prevent fatigue-induced cramping, the mechanism is unlikely to involve the autoinhibition produced by the golgi tendon organ reflex. Further empirical research is needed to validate the proposed link between static stretching and cramping and then to investigate alternative mechanisms.

  12. Acute Whole-Body Vibration does not Facilitate Peak Torque and Stretch Reflex in Healthy Adults

    Directory of Open Access Journals (Sweden)

    Ella W. Yeung

    2013-03-01

    Full Text Available The acute effect of whole-body vibration (WBV training may enhance muscular performance via neural potentiation of the stretch reflex. The purpose of this study was to investigate if acute WBV exposure affects the stretch induced knee jerk reflex [onset latency and electromechanical delay (EMD] and the isokinetic knee extensor peak torque performance. Twenty-two subjects were randomly assigned to the intervention or control group. The intervention group received WBV in a semi-squat position at 30° knee flexion with an amplitude of 0.69 mm, frequency of 45 Hz, and peak acceleration of 27.6 m/s2 for 3 minutes. The control group underwent the same semii-squatting position statically without exposure of WBV. Two-way mixed repeated measures analysis of variance revealed no significant group effects differences on reflex latency of rectus femoris (RF and vastus lateralis (VL; p = 0.934 and 0.935, respectively EMD of RF and VL (p = 0.474 and 0.551, respectively and peak torque production (p = 0.483 measured before and after the WBV. The results of this study indicate that a single session of WBV exposure has no potentiation effect on the stretch induced reflex and peak torque performance in healthy young adults.

  13. Elbow spasticity during passive stretch-reflex: clinical evaluation using a wearable sensor system

    Science.gov (United States)

    2013-01-01

    Background Spasticity is a prevalent chronic condition among persons with upper motor neuron syndrome that significantly impacts function and can be costly to treat. Clinical assessment is most often performed with passive stretch-reflex tests and graded on a scale, such as the Modified Ashworth Scale (MAS). However, these scales are limited in sensitivity and are highly subjective. This paper shows that a simple wearable sensor system (angle sensor and 2-channel EMG) worn during a stretch-reflex assessment can be used to more objectively quantify spasticity in a clinical setting. Methods A wearable sensor system consisting of a fibre-optic goniometer and 2-channel electromyography (EMG) was used to capture data during administration of the passive stretch-reflex test for elbow flexor and extensor spasticity. A kinematic model of unrestricted passive joint motion was used to extract metrics from the kinematic and EMG data to represent the intensity of the involuntary reflex. Relationships between the biometric results and clinical measures (MAS, isometric muscle strength and passive range of motion) were explored. Results Preliminary results based on nine patients with varying degrees of flexor and extensor spasticity showed that kinematic and EMG derived metrics were strongly correlated with one another, were correlated positively (and significantly) with clinical MAS, and negatively correlated (though mostly non-significant) with isometric muscle strength. Conclusions We conclude that a wearable sensor system used in conjunction with a simple kinematic model can capture clinically relevant features of elbow spasticity during stretch-reflex testing in a clinical environment. PMID:23782931

  14. Influence of jaw gape on EMG of jaw muscles and jaw-stretch reflexes.

    Science.gov (United States)

    Wang, Kelun; Lobbezoo, Frank; Svensson, Peter; Arendt-Nielsen, Lars

    2007-06-01

    The influence of jaw gapes on jaw-stretch reflexes and jaw muscles activity was studied in order to test the sensitivity of human muscle spindle afferents in various jaw muscles. Twelve healthy men (mean age+/-S.E.M.: 25.0+/-1.2yr) participated in the study. Short-latency excitatory reflex responses were evoked by a custom-made stretch device with the subjects biting on a jaw-bar with their front teeth. Surface electromyographic (sEMG) recordings from right masseter (MAR), and right temporalis (TAR), intramuscular EMG (imEMG) recordings from right lateral pterygoid (LPR) and right anterior digastric (ADR) muscles were made. The reflex at different jaw gapes of 6, 10, 14, 18, 22, 26, 30, 34, and 38mm were examined in random order with standard stretch conditions of 1mm displacement and 10ms ramp time. Twenty sweeps of the reflex were recorded at each level with at least 5s interval between each sweep with online monitoring of the visual feed back at 15% of maximum voluntary contraction (MVC) of each jaw gape from MAR. The results showed that the peak-to-peak amplitude of the jaw-stretch reflex in MAR was significantly higher at 14mm compared to 30, 34, and 38mm (Pjaw gape until a maximum at 34mm. There was no significant effect of jaw gape in LPR muscles (P=0.825) and no obvious stretch reflex was observed in ADR. When the amplitude was normalised to the pre-stimulus EMG at each jaw gape, the highest normalised amplitude was observed at 14mm jaw gape in MAR, however there was no significant effect of jaw gape on the normalised amplitude in TAR and LPR. In addition, masseter EMG at MVC significantly decreased with the increase of the gapes, i.e. biting at 6, 14, and 18mm gapes had a significantly higher MVC compared to 26, 30, 34, and 38mm (ANOVA: Pjaw gapes influence the sensitivity of the human muscle spindle afferents in jaw-closing muscles with a distinct peak, which is within normal jaw gapes during function.

  15. The tonic stretch reflex and spastic hypertonia after spinal cord injury.

    Science.gov (United States)

    Woolacott, Adam J; Burne, John A

    2006-09-01

    The operational definition of spasticity is focused on increased resistance of joints to passive rotation and the possible origin of this increased resistance in the induced tonic stretch reflex (TSR). This term is applied in the context of both cerebral and spinal injury, implying that a similar reflex mechanism underlies the two disorders. From recent studies it is clear that increased passive joint resistance in resting limbs following stroke is highly correlated with the induced TSR, but this evidence is lacking in spinal injury. The contribution of the TSR to hypertonia in spinal cord injury (SCI) is unclear and it is possible that hypertonia has a different origin in SCI. The contribution of resting and activated TSR activity to joint stiffness was compared in SCI and normal subjects. The magnitude of the TSR in ankle dorsiflexors (DF) and plantarflexors (PF) and mechanical ankle resistive torque were measured at rest and over a range of contraction levels in normal subjects. Similar measures were made in 13 subjects with SCI to the limits of their range of voluntary contraction. Normals and SCI received a pseudo-sinusoidal stretch perturbation of maximum amplitude +/- 20 degrees and frequency band 0.1-3.5 Hz that was comparable to that used in manual clinical testing of muscle tone. Elastic resistance and resonant frequency of the ankle joint, after normalization for limb volume, were significantly lower in complete and incomplete SCI than normal subjects. No reflex response related to stretch velocity was observed. Resting DF and PF TSR gain, when averaged over the tested band of frequencies, were significantly lower in complete SCI than in resting normal subjects (voluntary contraction level and regression analysis produced similar slopes in incomplete SCI and normal subjects. Hence TSR loop gain was not significantly increased in SCI at any equivalent contraction level. Extrapolation of the regression lines to zero contraction level predicted that reflex

  16. Decoupling of stretch reflex and background muscle activity during anticipatory postural adjustments in humans.

    Science.gov (United States)

    Vedula, Siddharth; Kearney, Robert E; Wagner, Ross; Stapley, Paul J

    2010-08-01

    We studied the evolution of stretch reflexes in relation to background electromyographic (EMG) activity in the soleus muscle preceding the onset of voluntary arm raise movements. Our objective was to investigate if changes in reflex EMG and muscle activity occur simultaneously and are similarly scaled in amplitude. Ten human subjects stood with each foot on pedals able to exert short dorsiflexor pulses during stance. Subjects were asked to product consistent voluntary arm raise movements to a target upon a visual cue. In (1/4) of trials, no pulse perturbations were given, but in the remaining (3/4)'s of all trials pulses were given randomly during a 600-ms period, from 400 ms before until 200 ms after the onset of the movements. Perturbation trials were sorted into 20-ms bins post hoc, and the amplitude of the reflex EMG component was calculated and compared to the EMG activity obtained when no pulses were given. Results showed that despite exhibiting similar profiles over time, the background EMG consistently inhibited before the reflex EMG did. However, times of reactivation (rebound) were variable across subjects, with background EMG activating before reflex for some subjects and vice versa for others. The minimum values of inhibition, time of inhibition and time of rebound for background and reflex EMG measures did not show significant linear correlations when all subjects' data were considered. These results suggest that reflex and background EMG components of anticipatory postural adjustments evolve differently in time and amplitude. This has implications for the independent control of reflexes and voluntary muscle activity.

  17. Modeling and Identification of a Realistic Spiking Neural Network and Musculoskeletal Model of the Human Arm, and an Application to the Stretch Reflex.

    Science.gov (United States)

    Sreenivasa, Manish; Ayusawa, Ko; Nakamura, Yoshihiko

    2016-05-01

    This study develops a multi-level neuromuscular model consisting of topological pools of spiking motor, sensory and interneurons controlling a bi-muscular model of the human arm. The spiking output of motor neuron pools were used to drive muscle actions and skeletal movement via neuromuscular junctions. Feedback information from muscle spindles were relayed via monosynaptic excitatory and disynaptic inhibitory connections, to simulate spinal afferent pathways. Subject-specific model parameters were identified from human experiments by using inverse dynamics computations and optimization methods. The identified neuromuscular model was used to simulate the biceps stretch reflex and the results were compared to an independent dataset. The proposed model was able to track the recorded data and produce dynamically consistent neural spiking patterns, muscle forces and movement kinematics under varying conditions of external forces and co-contraction levels. This additional layer of detail in neuromuscular models has important relevance to the research communities of rehabilitation and clinical movement analysis by providing a mathematical approach to studying neuromuscular pathology.

  18. Effects of Bed Rest on Conduction Velocity of the Triceps Surae Stretch Reflex and Postural Control

    Science.gov (United States)

    Reschke, M. F.; Wood, S. J.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Esteves, J. T.; Taylor, L. C.; DeDios, Y. E.; Harm, D. L.

    2011-01-01

    Despite rigorous exercise and nutritional management during space missions, astronauts returning from microgravity exhibit neuromuscular deficits and a significant loss in muscle mass in the postural muscles of the lower leg. Similar changes in the postural muscles occur in subjects participating in long-duration bed rest studies. These adaptive muscle changes manifest as a reduction in reflex conduction velocity during head-down bed rest. Because the stretch reflex encompasses both the peripheral (muscle spindle and nerve axon) and central (spinal synapse) components involved in adaptation to calf muscle unloading, it may be used to provide feedback on the general condition of neuromuscular function, and might be used to evaluate the effectiveness of countermeasures aimed at preserving muscle mass and function during periods of unloading. Stretch reflexes were measured on 18 control subjects who spent 60 to 90 days in continuous 6 deg head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 degrees at a peak velocity of about 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender. Computerized posturography was also conducted on these same subjects before and after bed rest as part of the standard measures. Peak-to-peak sway was measured during Sensory Organization Tests (SOTs) to evaluate changes in the ability to effectively use or suppress visual, vestibular, and proprioceptive information for postural control. Although no gender differences were found, a significant increase in reflex latency and a significant decrease in CV were observed during the bed

  19. Requirement for Dicer in Maintenance of Monosynaptic Sensory-Motor Circuits in the Spinal Cord.

    Science.gov (United States)

    Imai, Fumiyasu; Chen, Xiaoting; Weirauch, Matthew T; Yoshida, Yutaka

    2016-11-22

    In contrast to our knowledge of mechanisms governing circuit formation, our understanding of how neural circuits are maintained is limited. Here, we show that Dicer, an RNaseIII protein required for processing microRNAs (miRNAs), is essential for maintenance of the spinal monosynaptic stretch reflex circuit in which group Ia proprioceptive sensory neurons form direct connections with motor neurons. In postnatal mice lacking Dicer in proprioceptor sensory neurons, there are no obvious defects in specificity or formation of monosynaptic sensory-motor connections. However, these circuits degrade through synapse loss and retraction of proprioceptive axonal projections from the ventral spinal cord. Peripheral terminals are also impaired without retracting from muscle targets. Interestingly, despite these central and peripheral axonal defects, proprioceptive neurons survive in the absence of Dicer-processed miRNAs. These findings reveal that Dicer, through its production of mature miRNAs, plays a key role in the maintenance of monosynaptic sensory-motor circuits.

  20. Variation of magnitude and timing of wrist flexor stretch reflex across the full range of voluntary activation.

    Science.gov (United States)

    Cathers, I; O'Dwyer, N; Neilson, P

    2004-08-01

    This paper reports an investigation of the magnitude and timing of the stretch reflex over the full range of activation of flexor carpi radialis. While it is well established that the magnitude of the reflex increases with the level of muscle activation, there have been few studies of reflex magnitude above 50% of maximum voluntary contraction (MVC) and virtually no study of the timing of the response in relation to activation level. Continuous small amplitude (approximately 2 degrees) perturbations were applied to the wrist of 12 normal subjects while they maintained contraction levels between 2.5-95% MVC, monitored via surface electromyography (EMG). Both narrow band (4-5 Hz) and broad band (0-10 Hz) stretch perturbations were employed. The gain (EMG output/stretch input) and phase advance of the reflex varied with the level of muscle activation in a similar manner for both types of stretch, but there were significant differences in the patterns of change due to stretch bandwidth. Consistent with previous studies, the group average reflex gain initially increased with muscle activation level and then saturated. Inspection of individual data, however, revealed that the gain reached a peak at about 60% MVC and then decreased at higher contraction levels, the pattern across the full range of activation being well described by quadratic functions (mean r2=0.82). This quadratic pattern has not been reported previously for the neural reflex response in any muscle but is consistent with the pattern that has been reliably observed in studies of the mechanical reflex response in lower limb muscles. In contrast to the pattern for reflex gain, the phase advance of the reflex (at a stretch frequency of 4.5 Hz) decreased linearly from approximately 130 degrees at the lowest contraction levels to approximately 50 degrees as maximum voluntary contraction was reached (mean r2=0.69). This decrease corresponds to a delay of 49 ms introduced centrally in reflex pathways. All

  1. Triceps surae short latency stretch reflexes contribute to ankle stiffness regulation during human running.

    Science.gov (United States)

    Cronin, Neil J; Carty, Christopher P; Barrett, Rod S

    2011-01-01

    During human running, short latency stretch reflexes (SLRs) are elicited in the triceps surae muscles, but the function of these responses is still a matter of controversy. As the SLR is primarily mediated by Ia afferent nerve fibres, various methods have been used to examine SLR function by selectively blocking the Ia pathway in seated, standing and walking paradigms, but stretch reflex function has not been examined in detail during running. The purpose of this study was to examine triceps surae SLR function at different running speeds using Achilles tendon vibration to modify SLR size. Ten healthy participants ran on an instrumented treadmill at speeds between 7 and 15 km/h under 2 Achilles tendon vibration conditions: no vibration and 90 Hz vibration. Surface EMG from the triceps surae and tibialis anterior muscles, and 3D lower limb kinematics and ground reaction forces were simultaneously collected. In response to vibration, the SLR was depressed in the triceps surae muscles at all speeds. This coincided with short-lasting yielding at the ankle joint at speeds between 7 and 12 km/h, suggesting that the SLR contributes to muscle stiffness regulation by minimising ankle yielding during the early contact phase of running. Furthermore, at the fastest speed of 15 km/h, the SLR was still depressed by vibration in all muscles but yielding was no longer evident. This finding suggests that the SLR has greater functional importance at slow to intermediate running speeds than at faster speeds.

  2. Triceps surae short latency stretch reflexes contribute to ankle stiffness regulation during human running.

    Directory of Open Access Journals (Sweden)

    Neil J Cronin

    Full Text Available During human running, short latency stretch reflexes (SLRs are elicited in the triceps surae muscles, but the function of these responses is still a matter of controversy. As the SLR is primarily mediated by Ia afferent nerve fibres, various methods have been used to examine SLR function by selectively blocking the Ia pathway in seated, standing and walking paradigms, but stretch reflex function has not been examined in detail during running. The purpose of this study was to examine triceps surae SLR function at different running speeds using Achilles tendon vibration to modify SLR size. Ten healthy participants ran on an instrumented treadmill at speeds between 7 and 15 km/h under 2 Achilles tendon vibration conditions: no vibration and 90 Hz vibration. Surface EMG from the triceps surae and tibialis anterior muscles, and 3D lower limb kinematics and ground reaction forces were simultaneously collected. In response to vibration, the SLR was depressed in the triceps surae muscles at all speeds. This coincided with short-lasting yielding at the ankle joint at speeds between 7 and 12 km/h, suggesting that the SLR contributes to muscle stiffness regulation by minimising ankle yielding during the early contact phase of running. Furthermore, at the fastest speed of 15 km/h, the SLR was still depressed by vibration in all muscles but yielding was no longer evident. This finding suggests that the SLR has greater functional importance at slow to intermediate running speeds than at faster speeds.

  3. Stretch reflexes of the proximal arm in a patient with mirror movements: absence of bilateral long-latency components.

    Science.gov (United States)

    Fellows, S J; Töpper, R; Schwarz, M; Thilmann, A F; Noth, J

    1996-04-01

    The stretch reflex responses evoked by unilateral limb displacement in distal (first dorsal interosseus (FDI)) and in proximal (biceps brachii (Bb)) arm muscles were studied during matched bilateral contractions in a patient with congenital mirror movements. In this patient unilateral transcortical magnetic stimulation (TMS) elicited not only the normal contralateral EMG response but also a clear ipsilateral component in the EMG of both proximal and distal arm muscles. As expected from previous studies, the ipsilateral FDI muscle responded to stretch of the index finger with short- (M1) and long-latency (M2) reflex components. In addition, the FDI contralateral to displacement exhibited an abnormal mirrored response corresponding to the M2 interval. In contrast, whereas the ipsilateral Bb responded to imposed elbow extension with a marked M1/M2 reflex response, no mirroring of either reflex component was apparent in the contralateral Bb EMG. If the mirroring of the M2 in the FDI is accepted as evidence for the transcortical nature of the M2 reflex response, then it follows that the absence of such mirroring in the Bb indicates that a transcortical mechanism cannot play a major role in the generation of long-latency stretch reflex responses in proximal arm muscles.

  4. Stretching

    Science.gov (United States)

    ... Can I Help Someone Who's Being Bullied? Volunteering Stretching KidsHealth > For Teens > Stretching Print A A A ... full range of motion of the joints. continue Stretching Stretching used to be considered the main activity ...

  5. Soleus stretch reflex inhibition in the early swing phase of gait using deep peroneal nerve stimulation in spastic stroke participants

    NARCIS (Netherlands)

    Voormolen, Marco M.; Ladouceur, Michel; Veltink, Petrus H.; Sinkjaer, Thomas

    2000-01-01

    Objectives: To investigate the feasibility of inhibiting the stretch reflex of the soleus muscle by a conditioning stimulus applied to the deep peroneal nerve in spastic stroke participants during the early swing phase of gait. - Materials and Methods: This study investigated the effect of an

  6. Muscle disuse caused by botulinum toxin injection leads to increased central gain of the stretch reflex in the rat

    DEFF Research Database (Denmark)

    Pingel, Jessica; Hultborn, Hans; Naslund-Koch, Lui

    2017-01-01

    Botulinum toxin (Btx) is used in children with cerebral palsy and other neurological patients to diminish spasticity and reduce the risk of development of contractures. Here, we investigated changes in the central gain of the stretch reflex circuitry in response to botulinum toxin injection...

  7. Identification of time-varying dynamics of the human triceps surae stretch reflex. I. Rapid isometric contraction.

    Science.gov (United States)

    Kirsch, R F; Kearney, R E; MacNeil, J B

    1993-01-01

    We have examined the time variations of stretch reflex dynamics throughout rapid voluntary changes in the isometric contraction level of the human triceps surae muscles. This was achieved by superimposing a small stochastic displacement upon many such changing contractions and then identifying the time-varying relationship between the perturbation and the evoked electromyograms (EMGs). An "ensemble" time-varying system identification technique was used to estimate these input-output dynamics as a set of impulse response functions, one for each time before, during, and after the change in contraction level, with a temporal resolution equal to the data acquisition rate. Three main findings resulted. First, stretch reflex gain (relating joint velocity to EMG) was significantly modulated during changes in voluntary contraction level, increasing as the subject contracted the muscles and decreasing as the subject relaxed. Second, stretch reflex dynamics did not change with contraction level, even when its gain varied substantially. Third, the time course of the gain changes closely followed the level of the EMG, even though the subjects used rather different activation and deactivation patterns. These results suggest that, for the behavior studied (i.e., rapid changes in isometric contraction level), stretch reflex gain and motoneuron pool activation level were controlled by a common descending command rather than being independently specified.

  8. Short-term pressure induced suppression of the short-latency response: a new methodology for investigating stretch reflexes

    DEFF Research Database (Denmark)

    Leukel, Christian; Lundbye-Jensen, Jesper; Gruber, Markus;

    2009-01-01

    During experiments involving ischemic nerve block, we noticed that the short-latency response (SLR) of evoked stretches in m. soleus decreased immediately following inflation of a pneumatic cuff surrounding the lower leg. The present study aimed to investigate this short-term effect of pressure...... and inflated cuff. Results of the protocols were as follows: 1) inflation of the cuff reduced the SLR but not the MLR; 2) the H-reflex, the M-wave, and, 3) SNAPs of n. tibialis remained unchanged with deflated and inflated cuff; 4) the SLR was dependent on the stretch velocity with deflated and also inflated...

  9. Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans

    DEFF Research Database (Denmark)

    Grey, Michael James; Ladouceur, Michel; Andersen, Jacob B.

    2001-01-01

    1. The objective of this study was to determine which afferents contribute to the medium latency response of the soleus stretch reflex resulting from an unexpected perturbation during human walking. 2. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h(-1) with the left ankle...... component (P = 0.004), whereas the medium latency component was unchanged (P = 0.437). 6. Two hours after the ingestion of tizanidine, an alpha(2)-adrenergic receptor agonist known to selectively depress the transmission in the group II afferent pathway, the medium latency reflex was strongly depressed (P...... = 0.007), whereas the short latency component was unchanged (P = 0.653). 7. An ankle block with lidocaine hydrochloride was performed to suppress the cutaneous afferents of the foot and ankle. Neither the short (P = 0.453) nor medium (P = 0.310) latency reflexes were changed. 8. Our results support...

  10. Anodal transcranial direct current stimulation (tDCS) decreases the amplitudes of long-latency stretch reflexes in cerebellar ataxia.

    Science.gov (United States)

    Grimaldi, Giuliana; Manto, Mario

    2013-11-01

    Recent studies suggest that the neuromodulation of the cerebellum using transcranial direct current stimulation (tDCS) could represent a new therapeutic strategy for the management of cerebellar disorders. Anodal tDCS of the cerebellum increases the excitability of the cerebellar cortex. We tested the effects of anodal tDCS applied over the cerebellum in ataxic patients. We studied (a) stretch reflexes (SR) in upper limb (SLSR: short-latency stretch reflexes; LLSR: long-latency stretch reflexes), (b) a coordination functional task in upper limbs based on mechanical counters (MCT: mechanical counter test), and (c) computerized posturography. tDCS did not change the amplitude of SLSR, but reduced significantly the amplitudes of LLSR. tDCS did not improve the MCT scores and did not modify posture. We suggest that anodal tDCS of the cerebellum reduces the amplitudes of LLSR by increasing the inhibitory effect exerted by the cerebellar cortex upon cerebellar nuclei. The absence of effect upon upper limb coordination and posture suggests that the cerebello-cerebral networks subserving these functions are less responsive to anodal tDCS of the cerebellum. Anodal tDCS of the cerebellum represents a novel experimental tool to investigate the effects of the cerebellar cortex on the modulation of the amplitudes of LLSR.

  11. Stretch Reflex as a Simple Measure to Evaluate the Efficacy of Potential Flight Countermeasures Using the Bed Rest Environment

    Science.gov (United States)

    Cerisano, J. M.; Reschke, M. F.; Kofman, I. S.; Fisher, E. A.; Harm, D. L.

    2010-01-01

    INTRODUCTION: Spaceflight is acknowledged to have significant effects on the major postural muscles. However, it has been difficult to separate the effects of ascending somatosensory changes caused by the unloading of these muscles during flight from changes in sensorimotor function caused by a descending vestibulo-cerebellar response to microgravity. It is hypothesized that bed rest is an adequate model to investigate postural muscle unloading given that spaceflight and bed rest may produce similar results in both nerve axon and muscle tissue. METHODS: To investigate this hypothesis, stretch reflexes were measured on 18 subjects who spent 60 to 90 days in continuous 6 head-down bed rest. Using a motorized system capable of rotating the foot around the ankle joint (dorsiflexion) through an angle of 10 deg at a peak velocity of approximately 250 deg/sec, a stretch reflex was recorded from the subject's left triceps surae muscle group. Using surface electromyography, about 300 reflex responses were obtained and ensemble-averaged on 3 separate days before bed rest, 3 to 4 times in bed, and 3 times after bed rest. The averaged responses for each test day were examined for reflex latency and conduction velocity (CV) across gender and compared with spaceflight data. RESULTS: Although no gender differences were found, bed rest induced changes in reflex latency and CV similar to the ones observed during spaceflight. Also, a relationship between CV and loss of muscle strength in the lower leg was observed for most bed rest subjects. CONCLUSION: Even though bed rest (limb unloading) alone may not mimic all of the synaptic and muscle tissue loss that is observed as a result of spaceflight, it can serve as a working analog of flight for the evaluation of potential countermeasures that may be beneficial in mitigating unwanted changes in the major postural muscles that are observed post flight.

  12. Bradykinin does not acutely sensitize the reflex pressor response during hindlimb skeletal muscle stretch in decerebrate rats.

    Science.gov (United States)

    Rollins, Korynne S; Smith, Joshua R; Esau, Peter J; Kempf, Evan A; Hopkins, Tyler D; Copp, Steven W

    2017-10-01

    Hindlimb skeletal muscle stretch (i.e., selective activation of the muscle mechanoreflex) in decerebrate rats evokes reflex increases in blood pressure and sympathetic nerve activity. Bradykinin has been found to sensitize mechanogated channels through a bradykinin B2 receptor-dependent mechanism. Moreover, bradykinin B2 receptor expression on sensory neurons is increased following chronic femoral artery ligation in the rat (a model of simulated peripheral artery disease). We tested the hypothesis that injection of bradykinin into the arterial supply of a hindlimb in decerebrate, unanesthetized rats would acutely augment (i.e., sensitize) the increase in blood pressure and renal sympathetic nerve activity during hindlimb muscle stretch to a greater extent in rats with a ligated femoral artery than in rats with a freely perfused femoral artery. The pressor response during static hindlimb muscle stretch was compared before and after hindlimb arterial injection of 0.5 µg of bradykinin. Injection of bradykinin increased blood pressure to a greater extent in "ligated" (n = 10) than "freely perfused" (n = 10) rats. The increase in blood pressure during hindlimb muscle stretch, however, was not different before vs. after bradykinin injection in freely perfused (14 ± 2 and 15 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.62) or ligated (15 ± 3 and 14 ± 2 mmHg for pre- and post-bradykinin, respectively, P = 0.80) rats. Likewise, the increase in renal sympathetic nerve activity during stretch was not different before vs. after bradykinin injection in either group of rats. We conclude that bradykinin did not acutely sensitize the pressor response during hindlimb skeletal muscle stretch in freely perfused or ligated decerebrate rats. Copyright © 2017 the American Physiological Society.

  13. Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury.

    Science.gov (United States)

    Mirbagheri, Mehdi M; Kindig, Matthew W; Niu, Xun

    2015-05-01

    We sought to determine the therapeutic effect of robotic-assisted step training (RAST) on neuromuscular abnormalities associated with spasticity by characterization of their recovery patterns in people with spinal cord injury (SCI). Twenty-three motor-incomplete SCI subjects received one-hour RAST sessions three times per week for 4 weeks, while an SCI control group received no training. Neuromuscular properties were assessed using ankle perturbations prior to and during the training, and a system-identification technique quantified stretch reflex and intrinsic stiffness magnitude and modulation with joint position. Growth-mixture modeling classified subjects based on similar intrinsic and reflex recovery patterns. All recovery classes in the RAST group presented significant (p<0.05) reductions in intrinsic and reflex stiffness magnitude and modulation with position; the control group presented no changes over time. Subjects with larger baseline abnormalities exhibited larger reductions, and over longer training periods. Our findings demonstrate that RAST can effectively reduce neuromuscular abnormalities, with greater improvements for subjects with higher baseline abnormalities. Our findings suggest, in addition to its primary goal of improving locomotor patterns, RAST can also reduce neuromuscular abnormalities associated with spasticity. These findings also demonstrate that these techniques can be used to characterize neuromuscular recovery patterns in response to various types of interventions. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  14. Instruction-dependent modulation of the long-latency stretch reflex is associated with indicators of startle.

    Science.gov (United States)

    Ravichandran, Vengateswaran J; Honeycutt, Claire F; Shemmell, Jonathan; Perreault, Eric J

    2013-09-01

    Long-latency responses elicited by postural perturbation are modulated by how a subject is instructed to respond to the perturbation, yet the neural pathways responsible for this modulation remain unclear. The goal of this study was to determine whether instruction-dependent modulation is associated with activity in brainstem pathways contributing to startle. Our hypothesis was that elbow perturbations can evoked startle, indicated by activity in the sternocleidomastoid muscle (SCM). Perturbation responses were compared to those elicited by a loud acoustic stimulus, known to elicit startle. Postural perturbations and startling acoustic stimuli both evoked SCM activity, but only when a ballistic elbow extension movement was planned. Both stimuli triggered SCM activity with the same probability. When SCM activity was present, there was an associated early onset of triceps electromyographic (EMG), as required for the planned movement. This early EMG onset occurred at a time often attributed to long-latency stretch reflexes (75-100 ms). The nature of the perturbation-triggered EMG (excitatory or inhibitory) was independent of the perturbation direction (flexion or extension) indicating that it was not a feedback response appropriate for returning the limb to its original position. The net EMG response to perturbations delivered after a movement had been planned could be explained as the sum of a stretch reflex opposing the perturbation and a startle-evoked response associated with the prepared movement. These results demonstrate that rapid perturbations can trigger early release of a planned ballistic movement, and that this release is associated with activity in the brainstem pathways contributing to startle reflexes.

  15. Soleus H-reflex gain in humans walking and running under simulated reduced gravity

    Science.gov (United States)

    Ferris, D. P.; Aagaard, P.; Simonsen, E. B.; Farley, C. T.; Dyhre-Poulsen, P.

    2001-01-01

    The Hoffmann (H-) reflex is an electrical analogue of the monosynaptic stretch reflex, elicited by bypassing the muscle spindle and directly stimulating the afferent nerve. Studying H-reflex modulation provides insight into how the nervous system centrally modulates stretch reflex responses.A common measure of H-reflex gain is the slope of the relationship between H-reflex amplitude and EMG amplitude. To examine soleus H-reflex gain across a range of EMG levels during human locomotion, we used simulated reduced gravity to reduce muscle activity. We hypothesised that H-reflex gain would be independent of gravity level.We recorded EMG from eight subjects walking (1.25 m s-1) and running (3.0 m s-1) at four gravity levels (1.0, 0.75, 0.5 and 0.25 G (Earth gravity)). We normalised the stimulus M-wave and resulting H-reflex to the maximal M-wave amplitude (Mmax) elicited throughout the stride to correct for movement of stimulus and recording electrodes relative to nerve and muscle fibres. Peak soleus EMG amplitude decreased by 30% for walking and for running over the fourfold change in gravity. As hypothesised, slopes of linear regressions fitted to H-reflex versus EMG data were independent of gravity for walking and running (ANOVA, P > 0.8). The slopes were also independent of gait (P > 0.6), contrary to previous studies. Walking had a greater y-intercept (19.9% Mmax) than running (-2.5% Mmax; P EMG, walking H-reflex amplitudes were higher than running H-reflex amplitudes by a constant amount. We conclude that the nervous system adjusts H-reflex threshold but not H-reflex gain between walking and running. These findings provide insight into potential neural mechanisms responsible for spinal modulation of the stretch reflex during human locomotion.

  16. Development of Device to Evoke Stretch Reflexes by Use of Electromagnetic Force for the Rehabilitation of the Hemiplegic Upper Limb after Stroke

    Science.gov (United States)

    Hayashi, Ryota; Ishimine, Tomoyasu; Kawahira, Kazumi; Yu, Yong; Tsujio, Showzow

    In this research, we focus on the method of rehabilitation with stretch reflexes for the hemiplegic upper limb in stroke patients. We propose a new device which utilizes electromagnetic force to evoke stretch reflexes. The device can exert an assisting force safely, because the electromagnetic force is non contact force. In this paper, we develop a support system applying the proposed device for the functional recovery training of the hemiplegic upper limb. The results obtained from several clinical tests with and without our support system are compared. Then we discuss the validity of our support system.

  17. Post-activation depression of soleus stretch reflexes in healthy and spastic humans

    DEFF Research Database (Denmark)

    Grey, Michael James; Klinge, Klaus; Crone, Clarissa

    2007-01-01

    Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased re...

  18. Acute Effects of Kinesio Taping on Knee Extensor Peak Torque and Stretch Reflex in Healthy Adults

    Science.gov (United States)

    Yeung, Simon S.; Yeung, Ella W.

    2016-01-01

    Abstract Kinesio Tex tape (KT) is used to prevent and treat sports-related injuries and to enhance muscle performance. It has been proposed that the direction of taping may either facilitate or inhibit the muscle by having different effects on cutaneous receptors that modulate excitability of the motor neurons. This study had 2 goals. First, we wished to determine if KT application affects muscle performance and if the method of application facilitates or inhibits muscle performance. This was assessed by measuring isokinetic knee extension peak torque in the knee extensor. Second, we assessed neurological effects of taping on the excitability of the motor neurons by measuring the reflex latency and action potential by electromyography (EMG) in the patellar reflex. The study was a single-blind, placebo-controlled crossover trial with 28 healthy volunteers with no history of knee injuries. Participants received facilitative KT treatment, inhibitory KT treatment, or Hypafix taping of the knee extensor. There were significant differences in the peak torque between 3 treatments (F(2,54) = 4.873, P < 0.01). Post hoc analysis revealed that facilitative KT treatment resulted in higher knee extensor peak torque performance than inhibitory KT treatment (P = 0.036, effect size 0.26). There were, however, no significant differences in the reflex latency (F(2,54) = 2.84, P = 0.067) nor in the EMG values (F(2,54) = 0.18, P = 0.837) in the patellar reflex between the 3 taping applications. The findings suggest that the direction of KT application over the muscle has specific effects on muscle performance. Given the magnitude of effect is small, interpretation of clinical significance should be considered with caution. The underlying mechanism warrants further investigation. PMID:26825916

  19. Acute Effects of Kinesio Taping on Knee Extensor Peak Torque and Stretch Reflex in Healthy Adults.

    Science.gov (United States)

    Yeung, Simon S; Yeung, Ella W

    2016-01-01

    Kinesio Tex tape (KT) is used to prevent and treat sports-related injuries and to enhance muscle performance. It has been proposed that the direction of taping may either facilitate or inhibit the muscle by having different effects on cutaneous receptors that modulate excitability of the motor neurons. This study had 2 goals. First, we wished to determine if KT application affects muscle performance and if the method of application facilitates or inhibits muscle performance. This was assessed by measuring isokinetic knee extension peak torque in the knee extensor. Second, we assessed neurological effects of taping on the excitability of the motor neurons by measuring the reflex latency and action potential by electromyography (EMG) in the patellar reflex. The study was a single-blind, placebo-controlled crossover trial with 28 healthy volunteers with no history of knee injuries. Participants received facilitative KT treatment, inhibitory KT treatment, or Hypafix taping of the knee extensor. There were significant differences in the peak torque between 3 treatments (F(2,54) = 4.873, P < 0.01). Post hoc analysis revealed that facilitative KT treatment resulted in higher knee extensor peak torque performance than inhibitory KT treatment (P = 0.036, effect size 0.26). There were, however, no significant differences in the reflex latency (F(2,54) = 2.84, P = 0.067) nor in the EMG values (F(2,54) = 0.18, P = 0.837) in the patellar reflex between the 3 taping applications. The findings suggest that the direction of KT application over the muscle has specific effects on muscle performance. Given the magnitude of effect is small, interpretation of clinical significance should be considered with caution. The underlying mechanism warrants further investigation.

  20. Effects of effort and EMG levels on short-latency stretch reflex modulation after varying background muscle contractions.

    Science.gov (United States)

    Ogiso, K; McBride, J M; Finni, T; Komi, P V

    2005-08-01

    It is known that the short-latency stretch reflex (SLSR) is modulated by the background muscle activity when it is elicited at matched torque levels. This study was designed to examine the effects of muscle contraction types before a stretch perturbation on SLSR in the human soleus muscle (SOL) when SLSR was elicited at the same levels of effort and at matched electromyographic (EMG) activity levels. A mechanical stretch perturbation was applied to the calf muscles when the ankle joint reached a ninety degree tibio-tarsal joint angle after the muscles performed an isometric (pre-ISO), shortening (pre-SHO) and lengthening contraction (pre-LEN). Subjects were seated on an ankle ergometer chair and developed 0%, 10%, 20%, 30%, 40%, 50%, 60% and 70% ankle joint torque (AJT) of maximum voluntary isometric plantar flexion contraction at 80 degrees in pre-SHO, at 90 degrees in pre-ISO and at 100 degrees in pre-LEN. After that, isometric or dynamic contractions started, and the subjects were asked to maintain effort levels as, needed, to maintain the target torque levels until the end of the stretch. They relaxed their muscles fully after the stretch. This chain of processes was consecutively repeated 10 times. EMG signals obtained from SOL were averaged after they were high-pass filtered and full-wave rectified. Some major findings resulted: (1) there were no differences in SLSR area in the active muscle between pre-ISO and pre-SHO, whereas its waveform was steeper in pre-ISO than in pre-SHO. (2) SLSR p-to-p amplitude and waveform were larger and steeper in the active muscle than in the relaxed one in all conditions, whereas they were independent of the effort levels once the muscle was activated. This led to steady SLSR modulation in response to the background muscle contraction in the active muscle regardless of whether the SLSR was elicited at matched AJT or EMG activity levels. These findings suggest that SLSR is closely related to the muscle spindle sensitivity

  1. Modulation of the stretch reflex arc to improve functional recovery after peripheral nerve injury

    OpenAIRE

    2016-01-01

    Després d'una lesió del sistema nerviós perifèric, aquest té la capacitat de regenerar però la seva recuperació funcional sol ser limitada, principalment degut a la inespecificitat de la reinnervació dels òrgans perifèrics i als canvis plàstics maladaptatius de la circuiteria espinal. En aquesta tesi hem volgut modular els canvis a la circuiteria espinal del reflex d'estirament per poder millorar la recuperació funcional després de lesions del nervi perifèric en un model animal. En primer llo...

  2. The relationship between dynamic balancing ability and posture-related modulation of the soleus H-reflex.

    Science.gov (United States)

    Kawaishi, Yu; Domen, Kazuhisa

    2016-02-01

    Soleus H-reflex reveals down modulation with increased postural difficulty. Role of this posture-related reflex modulation is thought to shift movement control toward higher motor centers in order to facilitate more precise postural control. Present study hypothesized that the ability to modulate H-reflex is related to one's ability to dynamically balance while in an unstable posture. This study examined the relationship between dynamic balancing ability and soleus H-reflex posture-related modulation. Thirty healthy adults participated. The soleus maximal H-reflex (Hmax), motor response (Mmax), and background EMG activity (bEMG) were obtained during three postural conditions: prone, open-legged standing, and closed-legged standing. Hmax/Mmax ratios were normalized via the corresponding bEMG in order to remove the effects of background muscle activity from the obtained H-reflex. Reflex modulation was calculated as the ratio of the normalized Hmax/Mmax ratios in one postural condition to another posture in a more difficult condition. Dynamic balancing ability was assessed by testing stability while standing on a wobble board. A significant negative correlation was observed between balancing scores and reflex modulation from open-legged standing to closed-legged standing. This suggests that the ability to modulate monosynaptic stretch reflex excitability in response to a changing posture is a significant factor for dynamic balancing.

  3. Effect of muscle relaxants on experimental jaw-muscle pain and jaw-stretch reflexes: a double-blind and placebo-controlled trial.

    Science.gov (United States)

    Svensson, Peter; Wang, Kelun; Arendt-Nielsen, Lars

    2003-01-01

    A randomised, double-blind, placebo-controlled three-way cross-over study was performed to investigate the effect of two muscle relaxants (tolperisone hydrochloride and pridinol mesilate) on experimental jaw-muscle pain and jaw-stretch reflexes. Fifteen healthy men participated in three randomised sessions separated by at least 1 week. In each session 300 mg tolperisone, 8 mg pridinol mesilate or placebo was administered orally as a single dose. One hour after drug administration 0.3 ml hypertonic saline (5.8%) was injected into the right masseter to produce muscle pain. Subjects continuously rated their perceived pain intensity on an electronic 10-cm visual analogue scale (VAS). The pressure pain threshold (PPT) was measured and short-latency reflex responses were evoked in the pre-contracted (15% maximal voluntary contraction) masseter and temporalis muscles by a standardised stretch device (1 mm displacement, 10 ms ramp time) before (baseline), 1 h after medication (post-drug), during ongoing experimental muscle pain (pain-post-drug), and 15 min after pain had vanished (post-pain). Analysis of variance demonstrated significantly lower VAS peak pain scores (5.9 +/- 0.4 cm) after administration of tolperisone hydrochloride compared with pridinol mesilate (6.8 +/- 0.4 cm) and placebo (6.6 +/- 0.4 cm) (P=0.020). Administration of pridinol mesilate was associated with a significant decrease in PPTs compared with tolperisone hydrochloride and placebo (P=0.002) after medication, but not after experimental jaw-muscle pain. The normalised peak-to-peak amplitude of the stretch reflexes were not significantly influenced by the test medication (P=0.762), but were in all sessions significantly facilitated during ongoing experimental jaw-muscle pain (P=0.034). In conclusion, tolperisone hydrochloride provides a small, albeit significant reduction in the perceived intensity of experimental jaw-muscle pain whereas the present dose had no effect on the short-latency jaw-stretch

  4. Reflexes in Psychiatry

    OpenAIRE

    Sanders, Richard D.; Gillig, Paulette Marie

    2011-01-01

    Psychiatric patients often do not cooperate fully with the neurologic examination. Reflexes virtually bypass patient effort and are difficult to consciously determine. This article reviews muscle stretch (deep tendon) reflexes, and pathological reflexes including the extensor plantar (Babinski) and primitive release reflexes. Topics include findings in common psychiatric and neurologic conditions and methods for eliciting these signs.

  5. Specificity of Monosynaptic Sensory-Motor Connections Imposed by Repellent Sema3E-PlexinD1 Signaling

    Directory of Open Access Journals (Sweden)

    Kaori Fukuhara

    2013-11-01

    Full Text Available In mammalian spinal cord, group Ia proprioceptive afferents form selective monosynaptic connections with a select group of motor pool targets. The extent to which sensory recognition of motor neurons contributes to the selectivity of sensory-motor connections remains unclear. We show here that proprioceptive sensory afferents that express PlexinD1 avoid forming monosynaptic connections with neurons in Sema3E+ motor pools yet are able to form direct connections with neurons in Sema3Eoff motor pools. Anatomical and electrophysiological analysis of mice in which Sema3E-PlexinD1 signaling has been deregulated or inactivated genetically reveals that repellent signaling underlies aspects of the specificity of monosynaptic sensory-motor connectivity in these reflex arcs. A semaphorin-based system of motor neuron recognition and repulsion therefore contributes to the formation of specific sensory-motor connections in mammalian spinal cord.

  6. The evidence for nitric oxide synthase immunopositivity in the monosynaptic Ia-motoneuron pathway of the dog.

    Science.gov (United States)

    Marsala, Jozef; Lukácová, Nadezda; Sulla, Igor; Wohlfahrt, Peter; Marsala, Martin

    2005-09-01

    size from 0.7 to >or=15.1 microm in length x 0.7 to 4.8 microm wide. Subsequent to identification of the afferent nitric oxide synthase immunoreactive limb of the monosynaptic Ia-motoneuron pathway on control sections, intramuscular injections of the retrograde tracer Fluorogold into the gastrocnemius-soleus muscles, combined with nitric oxide synthase immunohistochemistry of L7 and S1 dorsal root ganglia, confirmed the existence of a number of medium-sized nitric oxide synthase immunoreactive somata (1000-2000 microm(2) square area) in the dorsolateral part of both dorsal root ganglia, presumed to be proprioceptive Ia neurons. Concurrently, large nitric oxide synthase immunoreactive fibers were detected at the input and output side of both dorsal root ganglia. S1 and S2 dorsal rhizotomy caused a marked depletion of nitric oxide synthase immunoreactivity in the medial bundle of S1 and S2 dorsal roots and in the dorsal funiculus of S1, S2 and lower lumbar segments. In addition, anterograde degeneration of large nitric oxide synthase immunoreactive Ia fibers in the dorsal funiculus of L7-S2 segments produces direct evidence that the afferent limb of the soleus H-reflex is nitric oxide synthase immunoreactive and presents new immunohistochemical characteristics of the monosynaptic Ia-motoneuron pathway, unseparably coupled with the performance of the stretch reflex.

  7. Alleviation of Motor Impairments in Patients with Cerebral Palsy: Acute Effects of Whole-body Vibration on Stretch Reflex Response, Voluntary Muscle Activation and Mobility.

    Science.gov (United States)

    Krause, Anne; Schönau, Eckhard; Gollhofer, Albert; Duran, Ibrahim; Ferrari-Malik, Anja; Freyler, Kathrin; Ritzmann, Ramona

    2017-01-01

    Individuals suffering from cerebral palsy (CP) often have involuntary, reflex-evoked muscle activity resulting in spastic hyperreflexia. Whole-body vibration (WBV) has been demonstrated to reduce reflex activity in healthy subjects, but evidence in CP patients is still limited. Therefore, this study aimed to establish the acute neuromuscular and kinematic effects of WBV in subjects with spastic CP. 44 children with spastic CP were tested on neuromuscular activation and kinematics before and immediately after a 1-min bout of WBV (16-25 Hz, 1.5-3 mm). Assessment included (1) recordings of stretch reflex (SR) activity of the triceps surae, (2) electromyography (EMG) measurements of maximal voluntary muscle activation of lower limb muscles, and (3) neuromuscular activation during active range of motion (aROM). We recorded EMG of m. soleus (SOL), m. gastrocnemius medialis (GM), m. tibialis anterior, m. vastus medialis, m. rectus femoris, and m. biceps femoris. Angular excursion was recorded by goniometry of the ankle and knee joint. After WBV, (1) SOL SRs were decreased (p control. This facilitation of muscle and joint control is probably due to a reduction of spasticity-associated spinal excitability in favor of giving access for greater supraspinal input during voluntary motor control.

  8. Alleviation of Motor Impairments in Patients with Cerebral Palsy: Acute Effects of Whole-body Vibration on Stretch Reflex Response, Voluntary Muscle Activation and Mobility

    Directory of Open Access Journals (Sweden)

    Anne Krause

    2017-08-01

    Full Text Available IntroductionIndividuals suffering from cerebral palsy (CP often have involuntary, reflex-evoked muscle activity resulting in spastic hyperreflexia. Whole-body vibration (WBV has been demonstrated to reduce reflex activity in healthy subjects, but evidence in CP patients is still limited. Therefore, this study aimed to establish the acute neuromuscular and kinematic effects of WBV in subjects with spastic CP.Methods44 children with spastic CP were tested on neuromuscular activation and kinematics before and immediately after a 1-min bout of WBV (16–25 Hz, 1.5–3 mm. Assessment included (1 recordings of stretch reflex (SR activity of the triceps surae, (2 electromyography (EMG measurements of maximal voluntary muscle activation of lower limb muscles, and (3 neuromuscular activation during active range of motion (aROM. We recorded EMG of m. soleus (SOL, m. gastrocnemius medialis (GM, m. tibialis anterior, m. vastus medialis, m. rectus femoris, and m. biceps femoris. Angular excursion was recorded by goniometry of the ankle and knee joint.ResultsAfter WBV, (1 SOL SRs were decreased (p < 0.01 while (2 maximal voluntary activation (p < 0.05 and (3 angular excursion in the knee joint (p < 0.01 were significantly increased. No changes could be observed for GM SR amplitudes or ankle joint excursion. Neuromuscular coordination expressed by greater agonist–antagonist ratios during aROM was significantly enhanced (p < 0.05.DiscussionThe findings point toward acute neuromuscular and kinematic effects following one bout of WBV. Protocols demonstrate that pathological reflex responses are reduced (spinal level, while the execution of voluntary movement (supraspinal level is improved in regards to kinematic and neuromuscular control. This facilitation of muscle and joint control is probably due to a reduction of spasticity-associated spinal excitability in favor of giving access for greater supraspinal input during voluntary motor

  9. A Comparison of the Effects of Continuous versus Discontinuous Movement Patterns on Parkinsonian Rigidity and Reflex Responses to Passive Stretch and Shortening

    Science.gov (United States)

    Powell, Douglas; Muthumani, Anburaj; Xia, RuiPing

    2016-01-01

    Objective Quantify the effect of a continuous compared to discontinuous movement trajectory on parkinsonian rigidity and reflex responses to passive stretch and shortening. Methods Eighteen participants with Parkinson’s disease (PD) performed passive wrist flexion and extension movements through a 90° range of motion at 50 °/sec using continuous (CONT) and discontinuous (DISC) movement trajectories. Participants were tested in both the OFF-MED and ON-MED states. Rigidity was quantified by rigidity work score and slopes of the moment-angle plots during both flexion and extension. Reflex response was quantified by mean EMG amplitudes of forearm musculature. Results No differences were observed between CONT and DISC for rigidity (p = 0.18) or moment-angle plot slopes (Flexion: p = 0.97; Extension: p = 0.89). However, medication was associated with reductions in rigidity (p = 0.02) and increases in moment-angle plot slopes (Flexion: p = 0.03; Extension: p = 0.02). The CONT compared to DISC trajectory was associated with greater EMG amplitudes in the shortened muscles (p = 0.04) and smaller EMG ratios (p < 0.05) during flexion, and greater EMG amplitudes in the lengthened muscles (p = 0.02) during extension. Dopaminergic medication reduced EMG amplitudes in stretched muscles during extension (p < 0.05). Conclusions The nature of the movement trajectory (continuous vs. discontinuous) used during clinical assessment does not alter the presentation of rigidity in PD. Rigidity is reduced with the administration of dopaminergic medication, independent of movement trajectory. Significance These data suggest that the presentation of rigidity used in the determination of diagnosis, treatment and prognosis in PD will not be affected by the continuous nature of the movement trajectory used during clinical assessment.

  10. Absence of synergy for monosynaptic Group I inputs between abdominal and internal intercostal motoneurons

    DEFF Research Database (Denmark)

    Ford, T W; Meehan, Claire Francesca; Kirkwood, P A

    2014-01-01

    , and the specificity of the monosynaptic connections from afferents in each of the two main branches of this nerve was investigated. Motoneurons were shown by antidromic excitation to innervate three muscle groups: external abdominal oblique [EO; innervated by the lateral branch (Lat)], the region of the internal...... motoneurons showed one from Lat. Expiratory Dist motoneurons fell into two groups. Those with Dist EPSPs and none from Lat (group A) were assumed to innervate distal internal intercostal muscle. Those with Lat EPSPs (group B) were assumed to innervate abdominal muscle (transversus abdominis or rectus......Internal intercostal and abdominal motoneurons are strongly coactivated during expiration. We investigated whether that synergy was paralleled by synergistic Group I reflex excitation. Intracellular recordings were made from motoneurons of the internal intercostal nerve of T8 in anesthetized cats...

  11. Absence of synergy for monosynaptic Group I inputs between abdominal and internal intercostal motoneurons.

    Science.gov (United States)

    Ford, T W; Meehan, C F; Kirkwood, P A

    2014-09-01

    Internal intercostal and abdominal motoneurons are strongly coactivated during expiration. We investigated whether that synergy was paralleled by synergistic Group I reflex excitation. Intracellular recordings were made from motoneurons of the internal intercostal nerve of T8 in anesthetized cats, and the specificity of the monosynaptic connections from afferents in each of the two main branches of this nerve was investigated. Motoneurons were shown by antidromic excitation to innervate three muscle groups: external abdominal oblique [EO; innervated by the lateral branch (Lat)], the region of the internal intercostal muscle proximal to the branch point (IIm), and muscles innervated from the distal remainder (Dist). Strong specificity was observed, only 2 of 54 motoneurons showing excitatory postsynaptic potentials (EPSPs) from both Lat and Dist. No EO motoneurons showed an EPSP from Dist, and no IIm motoneurons showed one from Lat. Expiratory Dist motoneurons fell into two groups. Those with Dist EPSPs and none from Lat (group A) were assumed to innervate distal internal intercostal muscle. Those with Lat EPSPs (group B) were assumed to innervate abdominal muscle (transversus abdominis or rectus abdominis). Inspiratory Dist motoneurons (assumed to innervate interchondral muscle) showed Dist EPSPs. Stimulation of dorsal ramus nerves gave EPSPs in 12 instances, 9 being in group B Dist motoneurons. The complete absence of heteronymous monosynaptic Group I reflex excitation between muscles that are synergistically activated in expiration leads us to conclude that such connections from muscle spindle afferents of the thoracic nerves have little role in controlling expiratory movements but, where present, support other motor acts. Copyright © 2014 the American Physiological Society.

  12. Monosynaptic Ia projections from intrinsic hand muscles to forearm motoneurones in humans

    Science.gov (United States)

    Marchand-Pauvert, V; Nicolas, G; Pierrot-Deseilligny, E

    2000-01-01

    Heteronymous Ia excitatory projections from intrinsic hand muscles to human forearm motoneurones (MNs) were investigated. Changes in firing probability of single motor units (MUs) in the flexor carpi radialis (FCR), flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), extensor carpi radialis (ECR), extensor carpi ulnaris (ECU) and extensor digitorum communis (EDC) were studied after electrical stimuli were applied to the median and ulnar nerve at wrist level and to the corresponding homonymous nerve at elbow level.Homonymous facilitation, occurring at the same latency as the H reflex, and therefore attributed to monosynaptic Ia EPSPs, was found in all the sampled units. In many MUs an early facilitation was also evoked by heteronymous low-threshold afferents from intrinsic hand muscles. The low threshold (between 0.5 and 0.6 times motor threshold (MT)) and the inability of a pure cutaneous stimulation to reproduce this effect indicate that it is due to stimulation of group I muscle afferents.Evidence for a similar central delay (monosynaptic) in heteronymous as in homonymous pathways was accepted when the difference in latencies of the homonymous and heteronymous peaks did not differ from the estimated supplementary afferent conduction time from wrist to elbow level by more than 0.5 ms (conduction velocity in the fastest Ia afferents between wrist and elbow levels being equal to 69 m s−1).A statistically significant heteronymous monosynaptic Ia excitation from intrinsic hand muscles supplied by both median and ulnar nerves was found in MUs belonging to all forearm motor nuclei tested (although not in ECU MUs after ulnar stimulation). It was, however, more often found in flexors than in extensors, in wrist than in finger muscles and in muscles operating in the radial than in the ulnar side.It is argued that the connections of Ia afferents from intrinsic hand muscles to forearm MNs, which are stronger and more widely distributed than in the cat, might

  13. The history of examination of reflexes.

    Science.gov (United States)

    Boes, Christopher J

    2014-12-01

    In the late 1800s, Wilhelm Erb, Joseph Babinski, William Gowers, and others helped develop the neurologic examination as we know it today. Erb was one of the first to emphasize a detailed and systematic neurologic exam and was co-discoverer of the muscle stretch reflex, Gowers began studying the knee jerk shortly after it was described, and Babinski focused on finding reliable signs that could differentiate organic from hysterical paralysis. These physicians and others emphasized the bedside examination of reflexes, which have been an important part of the neurologic examination ever since. This review will focus on the history of the examination of the following muscle stretch and superficial/cutaneous reflexes: knee jerk, jaw jerk, deep abdominal reflexes, superficial abdominal reflexes, plantar reflex/Babinski sign, and palmomental reflex. The history of reflex grading will also be discussed.

  14. Stretch marks

    Science.gov (United States)

    Stretch marks can appear when there is rapid stretching of the skin. They are often seen when ... often disappear after the cause of the skin stretching is gone. Avoiding rapid weight gain helps reduce ...

  15. Improved Monosynaptic Neural Circuit Tracing Using Engineered Rabies Virus Glycoproteins

    Directory of Open Access Journals (Sweden)

    Euiseok J. Kim

    2016-04-01

    Full Text Available Monosynaptic rabies virus tracing is a unique and powerful tool used to identify neurons making direct presynaptic connections onto neurons of interest across the entire nervous system. Current methods utilize complementation of glycoprotein gene-deleted rabies of the SAD B19 strain with its glycoprotein, B19G, to mediate retrograde transsynaptic spread across a single synaptic step. In most conditions, this method labels only a fraction of input neurons and would thus benefit from improved efficiency of transsynaptic spread. Here, we report newly engineered glycoprotein variants to improve transsynaptic efficiency. Among them, oG (optimized glycoprotein is a codon-optimized version of a chimeric glycoprotein consisting of the transmembrane/cytoplasmic domain of B19G and the extracellular domain of rabies Pasteur virus strain glycoprotein. We demonstrate that oG increases the tracing efficiency for long-distance input neurons up to 20-fold compared to B19G. oG-mediated rabies tracing will therefore allow identification and study of more complete monosynaptic input neural networks.

  16. Distributed and Mixed Information in Monosynaptic Inputs to Dopamine Neurons.

    Science.gov (United States)

    Tian, Ju; Huang, Ryan; Cohen, Jeremiah Y; Osakada, Fumitaka; Kobak, Dmitry; Machens, Christian K; Callaway, Edward M; Uchida, Naoshige; Watabe-Uchida, Mitsuko

    2016-09-21

    Dopamine neurons encode the difference between actual and predicted reward, or reward prediction error (RPE). Although many models have been proposed to account for this computation, it has been difficult to test these models experimentally. Here we established an awake electrophysiological recording system, combined with rabies virus and optogenetic cell-type identification, to characterize the firing patterns of monosynaptic inputs to dopamine neurons while mice performed classical conditioning tasks. We found that each variable required to compute RPE, including actual and predicted reward, was distributed in input neurons in multiple brain areas. Further, many input neurons across brain areas signaled combinations of these variables. These results demonstrate that even simple arithmetic computations such as RPE are not localized in specific brain areas but, rather, distributed across multiple nodes in a brain-wide network. Our systematic method to examine both activity and connectivity revealed unexpected redundancy for a simple computation in the brain.

  17. Differential effects of (-)-baclofen on Ia and descending monosynaptic EPSPs.

    Science.gov (United States)

    Jiménez, I; Rudomin, P; Enriquez, M

    1991-01-01

    1. In cats anesthetized with alpha-chloralose, population synaptic responses of motoneurons produced by stimulation of group I afferents were recorded from ventral roots with a sucrose gap or extracellularly from the motor pool. These responses were depressed, and often abolished, following the intravenous injection of 1-3 mg/kg of (-)-baclofen, a presumed GABAb agonist. 2. The monosynaptic population responses of motoneurons produced by stimulation of the ipsilateral ventromedial funiculus (VMF), the bulbar reticular formation or the vestibular nucleus, were also depressed following the administration of (-)-baclofen, but to a lesser degree than responses produced by stimulation of group I fibers. 3. Depression of the synaptic actions of Ia and of descending fibers following the administration of (-)-baclofen occurred without significant changes in the presynaptic volley recorded from the cord dorsum. However, in 3/4 experiments the intraspinally recorded Ia terminal potential was reduced following the injection of (-)-baclofen. The VMF terminal potentials were also depressed, but to a lesser degree. 4. Intracellular recordings from spinal motoneurons indicate that the (-)-baclofen-induced depression of the monosynaptic Ia- and VMF-EPSPs occurred without important changes in the time course of EPSP decay. This suggests that with the amounts used, postsynaptic changes were not contributing significantly to the EPSP depression. 5. It is suggested that (-)-baclofen depresses synaptic transmission probably by activation of GABAb receptors located at the intraspinal terminations of Ia and descending fibers. The lower sensitivity of VMF actions to (-)-baclofen would be accounted for by a relatively low density of baclofen receptors in descending fiber terminals.

  18. Stretch Marks

    Science.gov (United States)

    ... to get rid of stretch marks, but the truth is that most don't work and are ... The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...

  19. Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury

    OpenAIRE

    Onushko, Tanya; Hyngstrom, Allison; Brian D Schmit

    2013-01-01

    Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conv...

  20. Mephenesin, methocarbamol, chlordiazepoxide and diazepam: actions on spinal reflexes and ventral root potentials.

    Science.gov (United States)

    Crankshaw, D P; Raper, C

    1970-01-01

    1. Dose levels of mephenesin, methocarbamol, chlordiazepoxide and diazepam which abolished polysynaptic reflex contractions had no effect on monosynaptic knee-jerk reflexes in chloralose anaesthetized cats.2. Ventral root potentials were recorded following stimulation of the corresponding dorsal root (L7 or S1), and the areas of the mono- and polysynaptic components were measured by planimetry.3. Dose levels of the drugs which abolished polysynaptic reflex contractions reduced the areas of the polysynaptic component of the ventral root potentials by about 50%. Mephenesin and methocarbamol reduced the area of the monosynaptic component to a similar extent. Chlordiazepoxide was less potent in this respect while diazepam was without effect at this dose level.4. Linear regression lines were calculated for the reduction in the mono- and polysynaptic components of ventral root potentials with increasing doses of each of the four drugs. With methocarbamol and mephenesin the lines were parallel and coincident. With chlordiazepoxide and diazepam they were parallel but not coincident. Large doses of diazepam were required to reduce the area of the monosynaptic component, this drug being the only one of the four tested to have a differential action on the two components which was statistically significant.5. The results are discussed in terms of depressant actions of the drugs on alpha-motorneurones, effects of the drugs at higher centres concerned with motor function, and the lack of evidence that spinal interneurones represent a specific site of action for centrally acting skeletal muscle relaxants.

  1. Inhibition of spinal reflexes by acetylsalicylate and metamizol (dipyrone) in rats.

    Science.gov (United States)

    Genç, O; Turgut, S; Turgut, G; Kortunay, S

    2003-11-01

    The effects of acetylsalicylate and metamizol on spinal monosynaptic reflexes were tested in spinal rats. Adult rats were anesthetized with ketamine, artificially ventilated, and spinalized at the C1 level. A laminectomy was performed in the lumbosacral region. Following electrical stimulation of the sciatic nerve by single pulses, the reflex potentials were recorded from the ipsilateral L5 ventral root. Acetylsalicylate was administered orally via nasogastric tube and metamizol intramuscularly. Acetylsalicylate (50 and 100 mg/kg) and metamizol (15 mg/kg) significantly decreased the amplitude of the reflex response (p metamizol dose did not significantly decrease the amplitude of the reflex response. The cyclooxygenase products of arachidonic acid may play an important role in regulating the reflex potential. Copyright 2003 S. Karger AG, Basel

  2. Simultaneous characterizations of reflex and nonreflex dynamic and static changes in spastic hemiparesis

    Science.gov (United States)

    Chung, Sun G.; Ren, Yupeng; Liu, Lin; Roth, Elliot J.; Rymer, W. Zev

    2013-01-01

    This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping. Tendon reflex was characterized with reflex gain and threshold. Reflexively, tonic reflex gain was increased in spastic ankles at rest (P hemiparesis may help to evaluate and treat them more effectively. PMID:23636726

  3. Muscle, reflex and central components in the control of the ankle joint in healthy and spastic man.

    Science.gov (United States)

    Sinkjaer, T

    1997-01-01

    In understanding the control of the ankle joint during different motor tasks, we have to investigate at least three components, namely the influence of i) the passive and intrinsic properties of the intact and active muscle system around the joint (termed the non-reflex component), ii) the mechanical importance of the stretch reflex in the stretched and unloaded muscles, and iii) the supraspinal control of the stretch reflex. This thesis is dealing with the importance of the three components in healthy and spastic persons during sitting, standing, and walking. The results are based on stretch reflex and H-reflex measurements from the ankle extensor muscles. During stretch reflex experiments the foot was mounted to a platform (portable during walking) from which the ankle joint torque and the position were measured. To elicit a stretch reflex, the ankle joint was rotated by a strong motor connected to the platform. The mechanical importance of the stretch reflex was investigated by measuring the changes in joint torque. Electrically, the stretch reflex was recorded as the compound muscle action potential through bipolar surface EMG electrodes placed over the soleus muscle. During H-reflex experiments, the tibial nerve was stimulated at the popliteal fossa and the H-reflex recorded over the soleus muscle as during stretch reflex experiments. To investigate how the contractile properties of a muscle in humans depend on the history of activation, we investigated the intrinsic stiffness of the ankle extensors in healthy subjects. At matched background contraction in sitting subjects, a prolonged contraction increased the intrinsic muscle stiffness by 49%. Muscle yielding has been considered especially important for understanding the reflex compensation. We found a general lack of muscle yield and a mechanically important non-reflex stiffness of the ankle extensors showing that non-reflex stiffness is a prominent factor in normal movements of the ankle joint. In both

  4. Activation of brainstem serotoninergic pathways decreases homosynaptic depression of monosynaptic responses of frog spinal motoneurons.

    Science.gov (United States)

    Cardona, A; Rudomin, P

    1983-12-05

    In the isolated neuraxis of the frog, low frequency stimulation (0.5-2 Hz) of the lateral columns produces monosynaptic responses in the ventral roots which are depressed with an exponential time course. Serotonin (10 mumol/liter) added to the bath, or stimulation of the brain-stem midline raphe nuclei, but not of the lateral reticular formation, reduced the magnitude of the low frequency depression of the responses. The above actions were abolished by methysergide (1 mumol/liter), a specific antagonist of serotonin. These observations show that the magnitude of the homosynaptic depression of monosynaptic responses of motoneurons can be controlled by descending serotonergic mechanisms. This action is considered to be an important component of the arousal behavior mediated by the brain-stem raphe nuclei.

  5. Monosynaptic connections between primary afferents and giant neurons in the turtle spinal dorsal horn

    DEFF Research Database (Denmark)

    Fernández, A; Radmilovich, M; Russo, R E

    1996-01-01

    This paper reports the occurrence of monosynaptic connections between dorsal root afferents and a distinct cell type-the giant neuron-deep in the dorsal horn of the turtle spinal cord. Light microscope studies combining Nissl stain and transganglionic HRP-labeling of the primary afferents have...... revealed the occurrence of axosomatic and axodendritic contacts between labeled boutons and giant neurons. The synaptic nature of these contacts has been confirmed by use of electron microscope procedures involving the partial three-dimensional reconstruction of identified giant neurons. Intracellular...... recording in spinal cord slices provided functional evidence indicating the monosynaptic connections between dorsal root afferents and giant neurons. The recorded neurons were morphologically identified by means of biocytin injection and with avidin conjugates. Electrical stimulation of the ipsilateral...

  6. High concentrations of divalent cations isolate monosynaptic inputs from local circuits in the auditory midbrain

    Directory of Open Access Journals (Sweden)

    Shobhana eSivaramakrishnan

    2013-10-01

    Full Text Available Hierarchical processing of sensory information occurs at multiple levels between the peripheral and central pathway. Different extents of convergence and divergence in top down and bottom up projections makes it difficult to separate the various components activated by a sensory input. In particular, hierarchical processing at sub-cortical levels is little understood. Here we have developed a method to isolate extrinsic inputs to the inferior colliculus (IC, a nucleus in the midbrain region of the auditory system, with extensive ascending and descending convergence. By applying a high concentration of divalent cations (HiDi locally within the IC, we isolate a HiDi-sensitive from a HiDi-insensitive component of responses evoked by afferent input in brain slices and in vivo during a sound stimulus. Our results suggest that the HiDi sensitive component is a monosynaptic input to the IC, while the HiDi-insensitive component is a local polysynaptic circuit. Monosynaptic inputs have short latencies, rapid rise times and underlie first spike latencies. Local inputs have variable delays and evoke long-lasting excitation. In vivo, local circuits have variable onset times and temporal profiles. Our results suggest that high concentrations of divalent cations should prove to be a widely useful method of isolating extrinsic monosynaptic inputs from local circuits in vivo.

  7. Shoulder reflexes

    DEFF Research Database (Denmark)

    Diederichsen, Louise; Krogsgaard, Michael; Voigt, Michael

    2002-01-01

    Dynamic shoulder stability is dependent on muscular coordination and sensory inputs. In the shoulder, mechanoreceptors are found in the coracoacromial ligament, the rotator cuff tendons, the musculotendinous junctions of the rotator cuff and in the capsule. The number of receptors in the capsule...... is small compared to the number in the other shoulder structures. Proprioceptive information from numerous receptors in muscles and tendons is mediated via fast conducting nervefibers and probably contribute more to kinaestethic sensation than information from capsule and ligaments. Therefore it seems...... likely that the joint receptors have a more distinct role for the kinaestethic sense than muscle receptors. In cats a direct reflex from the afferents innervating the shoulder to the muscles around the shoulder has been presented. The reflex had an extremely short latency (2.7-3.1 ms). In man, a very...

  8. Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles.

    Science.gov (United States)

    Matsuo, Kiyoshi; Osada, Yoshiro; Ban, Ryokuya

    2013-02-01

    The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

  9. Stretch Sensor Device

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases....... Thereby the stretch values determined from the stretch samples have a particular physical meaning since they are associated with particular motion phases....

  10. Characteristics of the spino-bulbo-spinal reflex with evoked EMGs in human subjects.

    Science.gov (United States)

    Ishikawa, T; Miyazawa, T; Fujiwara, T

    1984-08-01

    Training in sports medicine and rehabilitation medicine requires the establishment of conditioned reflexes. Reinforcement of a conditioned reflex is more effective when it is part of a set of two or three reflexes. The late spinal reflexes appearing after conditioning were resolved into a stretch reflex and a spino-bulbo-spinal (SBS) reflex. H and M waves on the tibialis anterior muscle induced by tibial nerve stimulation were determined from the escape potential of the triceps sural muscle contraction. The tibial nerve and peroneal nerve were stimulated bilaterally, and H and M waves from the triceps sural muscle and tibialis anterior muscle were recorded bilaterally. The complete separation method of the late response and the time course of the stretch reflex and SBS reflex that composed the late response are described in this paper.

  11. Stretch Sensor Device

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

  12. Stretching Safely and Effectively

    Science.gov (United States)

    ... it safely and effectively. By Mayo Clinic Staff Stretching may take a back seat to your exercise routine. The main concern is exercising, not stretching, right? Not so fast. Stretching may help you: ...

  13. WEAKLY ALGEBRAIC REFLEXIVITY AND STRONGLY ALGEBRAIC REFLEXIVITY

    Institute of Scientific and Technical Information of China (English)

    TaoChangli; LuShijie; ChenPeixin

    2002-01-01

    Algebraic reflexivity introduced by Hadwin is related to linear interpolation. In this paper, the concepts of weakly algebraic reflexivity and strongly algebraic reflexivity which are also related to linear interpolation are introduced. Some properties of them are obtained and some relations between them revealed.

  14. Specificity of reflex adaptation for task-relevant variability.

    Science.gov (United States)

    Franklin, David W; Wolpert, Daniel M

    2008-12-24

    The motor system responds to perturbations with reflexes, such as the vestibulo-ocular reflex or stretch reflex, whose gains adapt in response to novel and fixed changes in the environment, such as magnifying spectacles or standing on a tilting platform. Here we demonstrate a reflex response to shifts in the hand's visual location during reaching, which occurs before the onset of voluntary reaction time, and investigate how its magnitude depends on statistical properties of the environment. We examine the change in reflex response to two different distributions of visuomotor discrepancies, both of which have zero mean and equal variance across trials. Critically one distribution is task relevant and the other task irrelevant. The task-relevant discrepancies are maintained to the end of the movement, whereas the task-irrelevant discrepancies are transient such that no discrepancy exists at the end of the movement. The reflex magnitude was assessed using identical probe trials under both distributions. We find opposite directions of adaptation of the reflex response under these two distributions, with increased reflex magnitudes for task-relevant variability and decreased reflex magnitudes for task-irrelevant variability. This demonstrates modulation of reflex magnitudes in the absence of a fixed change in the environment, and shows that reflexes are sensitive to the statistics of tasks with modulation depending on whether the variability is task relevant or task irrelevant.

  15. Anticipatory modulation of neck muscle reflex responses induced by mechanical perturbations of the human forehead.

    Science.gov (United States)

    Kuramochi, Rieko; Kimura, Toshitaka; Nakazawa, Kimitaka; Akai, Masami; Torii, Suguru; Suzuki, Shuji

    2004-08-12

    The aim of this study was to test whether anticipation of upcoming head blow stimuli, which elicit reflex responses in the neck muscle, makes the reflex responses greater or not. In nine healthy subjects the reflex responses were elicited in the sternocleidomastoid (SCM) muscle in the eyes-open (EO) and eyes-closed (EC) conditions, which corresponded to the predictable and unpredictable conditions, respectively. The subjects were instructed not to resist the perturbations after the impact. The results demonstrated that the reflex response of the SCM muscle was significantly smaller in the predictable EO condition than in the unpredictable EC condition (P component, which most probably mediated the stretch reflex pathway. In contrast, no significant difference was observed in the early component, which was presumed to be the vestibular-collic reflex. The reduced stretch reflex response was suggested to be functionally relevant to the task requirement, i.e., to let the neck extension movement occur, and not to resist after the impact of the head blow. It was concluded that the anticipation has an effect on reducing the stretch reflex responses in the neck muscle, but does not have any effect on the presumed vestibular-collic reflex under the present experimental paradigm. It is suggested that the gain of the stretch reflex pathway is modulated by anticipatory information of upcoming mechanical event.

  16. Reflexive cacti: a survey

    OpenAIRE

    Bojana Mihailović; Marija Rašajski; Zoran Stanić

    2016-01-01

    A graph is called reflexive if its second largest eigenvalue does not exceed 2. We survey the results on reflexive cacti obtained in the last two decades. We also discuss various patterns of appearing of Smith graphs as subgraphs of reflexive cacti. In the Appendix, we survey the recent results concerning reflexive bipartite regular graphs.

  17. The nasocardiac reflex.

    Science.gov (United States)

    Baxandall, M L; Thorn, J L

    1988-06-01

    The oculocardiac reflex is well described and recognised in anaesthesia. The nasocardiac reflex is less well-known. We describe a clinical manifestation of this reflex and describe the relevant anatomy. This reflex may be obtunded during general anaesthesia. during general anaesthesia.

  18. Reflexives in Veracruz Huastec.

    Science.gov (United States)

    Constable, Peter G.

    A study examines various Huastec clause types that are reflexive in some sense, including ordinary reflexives, which involve co-reference. Two mutually exclusive morphosyntactic devices are used in Huastec: reflexive pronouns and verbal morphology. In this way, Huastec is like various European languages. Clauses involving reflexive pronouns and…

  19. Primary afferent depolarization and flexion reflexes produced by radiant heat stimulation of the skin.

    Science.gov (United States)

    Burke, R E; Rudomin, P; Vyklický, L; Zajac, F E

    1971-02-01

    1. The reflex effects of pulses of intense radiant heat applied to the skin of the central plantar pad have been studied in unanaesthetized (decerebrate) spinal cats.2. Pad heat pulses produced flexion of the ipsilateral hind limb and increased ipsilateral flexor monosynaptic reflexes, due to post-synaptic excitation of flexor alpha motoneurones. These effects were accompanied by reduction of extensor monosynaptic reflexes and post-synaptic inhibition of extensor motoneurones.3. Ipsilateral (and contralateral) pad heat pulses consistently evoked negative dorsal root potentials (DRPs) as well as increased excitability of both cutaneous and group Ib muscle afferent terminals. The excitability of group Ia afferents was sometimes also increased during pad heat pulses, but to a lesser extent.4. Pad heat pulses produced negative DRPs in preparations in which positive DRP components could be demonstrated following electrical stimulation of both skin and muscle nerves.5. The motor and primary afferent effects of heat pulses always accompanied one another, beginning after the pad surface temperature had reached rather high levels (usually 48-55 degrees C).6. Negative DRPs increased excitability of cutaneous and group Ib afferents, and motoneurone activation produced by pad heat pulses was essentially unmodified when conduction in large myelinated afferents from the central plantar pad was blocked by cooling the posterior tibial nerve trunk.7. It is concluded that adequate noxious activation of cutaneous afferents of small diameter produces primary afferent depolarization in a variety of large diameter afferent fibres, as well as post-synaptic effects in alpha motoneurones.

  20. Dual effect of GABA on descending monosynaptic excitatory postsynaptic potential in frog lumbar motoneurons.

    Science.gov (United States)

    Ovsepian, S V; Vesselkin, N P

    2004-01-01

    Monosynaptic excitatory postsynaptic potentials (EPSPs) evoked by stimulating ipsilateral ventrolateral column (VLC) in the thoracic section were recorded in lumbar motoneurons within the isolated spinal cord of the frog Rana ridibunda. Bath application of the selective GABAB receptor agonist (-)-baclofen (0.05 mM) caused a reduction in the peak amplitude of VLC EPSP. Baclofen did not cause any consistent change in the membrane potential or in the EPSP waveform within frog motoneurones. The selective GABA(B) receptor antagonist saclofen (0.1 mM) completely blocked the effect of (-)-baclofen on VLC EPSP. A decrease in VLC EPSP peak amplitude was also observed during GABA (0.5 mM) application. Unlike (-)-baclofen, inhibition of VLC EPSP induced by GABA was accompanied by a shortening of the EPSP time course and a reduction in membrane input resistance within lumbar motoneurons. The decrease in VLC EPSP peak amplitude induced by (-)-baclofen and GABA was accompanied by an increase in the paired-pulse facilitation. These data provide evidence for a dual pre- and postsynaptic GABAergic inhibition of the VLC monosynaptic EPSP in lumbar motoneurons within the frog spinal cord.

  1. Myoelectric silence following unopposed passive stretch in normal man.

    Science.gov (United States)

    Angel, R W; Waxman, S G; Kocsis, J D

    1980-08-01

    The response to unopposed passive muscle stretch applied during sustained contraction was studied in normal man. When the subject did not resist the stretching force, the initial response was a brief cessation of EMG activity in the elongated muscle. The myoelectric silence was observed repeatedly in muscles of the upper and lower limbs. The response to passive stretch is discussed in relation to the lengthening reaction and the inverse myotatic reflex. The silent period observed under these experimental conditions is unlikely to be caused by Renshaw inhibition, a pause in spindle afferent discharge, or activity of the group II afferent reflex pathway. Possible mechanisms include autogenetic inhibition and a stretch-evoked decrease of fusimotor activity.

  2. Monosynaptic responses of ventral roots of spinal cord in experimental diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Rodinsky A.G.

    2014-03-01

    Full Text Available In intact rats and rats with experimental diabetes mellitus (DM threshold, chronaxia, latent period, duration and amplitude of monosynaptic discharges of ventral root, as well as refractory periods in response to its paired stimulation were analyzed. There as found out increase in the threshold of excitability by 2 times (p0,05. In the response to paired stimulation there was obtained a significant increase in the amplitude of action potential under experimental DM in the interval of 2-5 ms between stimulation. There was made a conclusion that in DM a decrease in excitability and conductivity of the spinal cord structures at the level of L5, occurred and a tendency to increase of ability to summation of excitation was seen.

  3. Hippocampal CA1 lacunosum-moleculare interneurons: modulation of monosynaptic GABAergic IPSCs by presynaptic GABAB receptors.

    Science.gov (United States)

    Khazipov, R; Congar, P; Ben-Ari, Y

    1995-11-01

    1. Whole cell patch-clamp recordings were employed to characterize monosynaptic inhibitory postsynaptic currents (IPSCs) in morphologically and electrophysiologically identified interneurons located in the stratum lacunosum moleculare, or near the border of the stratum radiatum (LM interneurons), in the CA1 region of hippocampal slices taken from 3- to 4-wk-old rats. Monosynaptic IPSCs, evoked in the presence of glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 20 microM) and D-2-amino-5-phosphopentanoate (APV; 50 microM) were biphasic. The gamma-aminobutyric acid-A (GABAA) receptor antagonist, bicuculline (20 microM), blocked the fast IPSC, and the slow IPSC was blocked by the GABAB receptor antagonist CGP35348 (500 microM). 2. Monosynaptic IPSCs were evoked by electrical stimulation in several distant regions including the stratum radiatum, the stratum oriens, the stratum lacunosum-moleculare, and the molecular layer of dentate gyrus, suggesting an extensive network of inhibitory interneurons in the hippocampus. In paired recordings of CA1 interneurons and pyramidal cells, IPSCs were evoked by electrical stimulation of most of these distal regions with the exception of the molecular layer of dentate gyrus, which evoked an IPSC only in LM interneurons. 3. Frequent (> 0.1 Hz) stimulation depressed the evoked IPSCs. With a paired-pulse protocol, the second IPSC was depressed and the maximal depression (40-50%) was observed with an interstimulus interval of 100-200 ms. 4. The GABAB receptor agonist baclofen (1 microM) reduced the amplitude of evoked IPSCs and the paired-pulse depression of the second IPSC. The GABAB receptor antagonist CGP35348 (0.5-1 mM) had no significant effect on the amplitude of isolated IPSCs. However, CGP35348 reduced but did not fully block paired-pulse depression, suggesting that this depression is partly due to the activation of presynaptic GABAB receptors. 5. The paired-pulse depression depended on the level of

  4. Activity-induced remodeling of olfactory bulb microcircuits revealed by monosynaptic tracing.

    Directory of Open Access Journals (Sweden)

    Benjamin R Arenkiel

    Full Text Available The continued addition of new neurons to mature olfactory circuits represents a remarkable mode of cellular and structural brain plasticity. However, the anatomical configuration of newly established circuits, the types and numbers of neurons that form new synaptic connections, and the effect of sensory experience on synaptic connectivity in the olfactory bulb remain poorly understood. Using in vivo electroporation and monosynaptic tracing, we show that postnatal-born granule cells form synaptic connections with centrifugal inputs and mitral/tufted cells in the mouse olfactory bulb. In addition, newly born granule cells receive extensive input from local inhibitory short axon cells, a poorly understood cell population. The connectivity of short axon cells shows clustered organization, and their synaptic input onto newborn granule cells dramatically and selectively expands with odor stimulation. Our findings suggest that sensory experience promotes the synaptic integration of new neurons into cell type-specific olfactory circuits.

  5. Monosynaptic functional connectivity in cerebral cortex during wakefulness and under graded levels of anesthesia

    Directory of Open Access Journals (Sweden)

    Jeannette A Vizuete

    2012-10-01

    Full Text Available The balance between excitation and inhibition is considered to be of significant importance for neural computation and cognitive function. Excitatory and inhibitory functional connectivity in intact cortical neuronal networks in wakefulness and graded levels of anesthesia has not been systematically investigated. We compared monosynaptic excitatory and inhibitory spike transmission probabilities using pairwise cross-correlogram analysis. Spikes were measured at 64 sites in the visual cortex of rats with chronically implanted microelectrode arrays during wakefulness and three levels of anesthesia produced by desflurane. Anesthesia decreased the number of active units, the number of functional connections, and the strength of excitatory connections. Connection probability (number of connections per number of active unit pairs was unaffected until the deepest anesthesia level, at which a significant increase in the excitatory to inhibitory ratio of connection probabilities was observed. The results suggest that the excitatory-inhibitory balance is altered at an anesthetic depth associated with unconsciousness.

  6. Organization of Monosynaptic Inputs to the Serotonin and Dopamine Neuromodulatory Systems

    Directory of Open Access Journals (Sweden)

    Sachie K. Ogawa

    2014-08-01

    Full Text Available Serotonin and dopamine are major neuromodulators. Here, we used a modified rabies virus to identify monosynaptic inputs to serotonin neurons in the dorsal and median raphe (DR and MR. We found that inputs to DR and MR serotonin neurons are spatially shifted in the forebrain, and MR serotonin neurons receive inputs from more medial structures. Then, we compared these data with inputs to dopamine neurons in the ventral tegmental area (VTA and substantia nigra pars compacta (SNc. We found that DR serotonin neurons receive inputs from a remarkably similar set of areas as VTA dopamine neurons apart from the striatum, which preferentially targets dopamine neurons. Our results suggest three major input streams: a medial stream regulates MR serotonin neurons, an intermediate stream regulates DR serotonin and VTA dopamine neurons, and a lateral stream regulates SNc dopamine neurons. These results provide fundamental organizational principles of afferent control for serotonin and dopamine.

  7. Embodied Self-Reflexivity

    Science.gov (United States)

    Pagis, Michal

    2009-01-01

    Drawing on G. H. Mead and Merleau-Ponty, this paper aims to extend our understanding of self-reflexivity beyond the notion of a discursive, abstract, and symbolic process. It offers a framework for embodied self-reflexivity, which anchors the self in the reflexive capacity of bodily sensations. The data consist of two years of ethnographic…

  8. BRAIN-STEM INFLUENCES ON BICEPS REFLEX ACTIVITY AND MUSCLE TONE IN THE ANESTHETIZED RAT

    NARCIS (Netherlands)

    JUCH, PJW; SCHAAFSMA, A; VANWILLIGEN, JD

    1992-01-01

    This study analyzes the effect of electrical stimulation of the locus coeruleus (LC) and adjacent brainstem structures on the tonic reflex (TVR), the tonic stretch reflex (TSR) and on muscle tone (MT) in anaesthetized rat. Increases in TVR. TSR and MT of the m. biceps were evoked from regions

  9. Long-Term Plasticity in Reflex Excitability Induced by Five Weeks of Arm and Leg Cycling Training after Stroke

    Directory of Open Access Journals (Sweden)

    Taryn Klarner

    2016-11-01

    Full Text Available Neural connections remain partially viable after stroke, and access to these residual connections provides a substrate for training-induced plasticity. The objective of this project was to test if reflex excitability could be modified with arm and leg (A & L cycling training. Nineteen individuals with chronic stroke (more than six months postlesion performed 30 min of A & L cycling training three times a week for five weeks. Changes in reflex excitability were inferred from modulation of cutaneous and stretch reflexes. A multiple baseline (three pretests within-subject control design was used. Plasticity in reflex excitability was determined as an increase in the conditioning effect of arm cycling on soleus stretch reflex amplitude on the more affected side, by the index of modulation, and by the modulation ratio between sides for cutaneous reflexes. In general, A & L cycling training induces plasticity and modifies reflex excitability after stroke.

  10. Reflexives and reflexive constructions in Afrikaans

    African Journals Online (AJOL)

    Kate H

    coreferential relationship between the pronoun and some other expression in the sentence. Keywords: reflexives ...... object argument, functions as the complement of a noun. Consider the ...... A minimalist approach to the syntax of. Dutch.

  11. Stretch reflex regulation in healthy subjects and patients with spasticity

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Petersen, Nicolas; Crone, Clarissa

    2005-01-01

    during voluntary muscle contraction in part because of depression of the inhibitory mechanisms that are affected in spasticity. In spastic patients, these inhibitory mechanisms are already depressed at rest and cannot be depressed further in connection with a contraction. In relation to most normal...

  12. Emotionally Colorful Reflexive Games

    CERN Document Server

    Tarasenko, Sergey

    2011-01-01

    This study addresses the matter of reflexive control of the emotional states by means of Reflexive Game Theory (RGT). It is shown how to build a bridge between RGT and emotions. For this purpose the Pleasure-Arousal-Dominance (PAD) model is adopted. The major advantages of RGT are its ability to predict human behavior and unfold the entire spectra of reflexion in the human mind. On the other hand, PAD provides ultimate approach to model emotions. It is illustrated that emotions are reflexive processes and, consequently, RGT fused with PAD model is natural solution to model emotional interactions between people. The fusion of RGT and PAD, called Emotional Reflexive Games (ERG), inherits the key features of both components. Using ERG, we show how reflexive control can be successfully applied to model human emotional states. Up to date, EGR is a unique methodology capable of modeling human reflexive processes and emotional aspects simultaneously.

  13. Reflex excitability regulates prepulse inhibition.

    Science.gov (United States)

    Schicatano, E J; Peshori, K R; Gopalaswamy, R; Sahay, E; Evinger, C

    2000-06-01

    Presentation of a weak stimulus, a prepulse, before a reflex-evoking stimulus decreases the amplitude of the reflex response relative to reflex amplitude evoked without a preceding prepulse. For example, presenting a brief tone before a trigeminal blink-eliciting stimulus significantly reduces reflex blink amplitude. A common explanation of such data are that sensory processing of the prepulse modifies reflex circuit behavior. The current study investigates the converse hypothesis that the intrinsic characteristics of the reflex circuit rather than prepulse processing determine prepulse modification of trigeminal and acoustic reflex blinks. Unilateral lesions of substantia nigra pars compacta neurons created rats with hyperexcitable trigeminal reflex blinks but normally excitable acoustic reflex blinks. In control rats, presentation of a prepulse reduced the amplitude of both trigeminal and acoustic reflex blinks. In 6-OHDA-lesioned rats, however, the same acoustic prepulse facilitated trigeminal reflex blinks but inhibited acoustic reflex blinks. The magnitude of prepulse modification correlated with reflex excitability. Humans exhibited the same pattern of prepulse modification. An acoustic prepulse facilitated the trigeminal reflex blinks of subjects with hyperexcitable trigeminal reflex blinks caused by Parkinson's disease. The same prepulse inhibited trigeminal reflex blinks of age-matched control subjects. Prepulse modification also correlated with trigeminal reflex blink excitability. These data show that reflex modification by a prepulse reflects the intrinsic characteristics of the reflex circuit rather than an external adjustment of the reflex circuit by the prepulse.

  14. The Fontana paradoxical reflex?

    Science.gov (United States)

    Lavorini, Federico; Fontana, Giovanni; Chellini, Elisa; Magni, Chiara; Pistolesi, Massimo; Widdicombe, John

    2011-09-01

    This commentary describes the "deflation cough" caused by deep lung deflations. Deflation cough is a paradoxical reflex similar to that described by Henry Head in 1889 for lung inflations that probably is mediated by the same sensors and afferent fibers in the lungs and activated by gastroesophageal reflux. We discuss how this reflex must be self-limiting, the general role of paradoxical reflexes in the body, and the possible clinical significance of deflation cough.

  15. Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury.

    Science.gov (United States)

    Onushko, Tanya; Hyngstrom, Allison; Schmit, Brian D

    2013-07-01

    Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects by oscillating the legs about the hip joint bilaterally from 10° of extension to 40° flexion. To test whether stretch-related feedback from the knee or ankle would be affected by hip movement, patellar tendon percussions and Achilles tendon vibration were delivered when the hip was either extending or flexing. Surface electromyograms (EMGs) and joint torques were recorded from both legs. Patellar tendon percussions and Achilles tendon vibration both elicited reflex responses local to the knee or ankle, respectively, and did not influence reflex responses observed at the hip. Rather, the movement direction of the hip modulated the reflex responses local to the joint. The patellar tendon reflex amplitude was larger when the perturbation was delivered during hip extension compared with hip flexion. The response to Achilles vibration was modulated by hip movement, with an increased tonic component during hip flexion compared with extension. These results demonstrate that hip-mediated sensory signals modulate activity in distal muscles of the leg and appear to play a unique role in modulation of spastic muscle activity throughout the leg in SCI.

  16. Stretching: Does It Help?

    Science.gov (United States)

    Vardiman, Phillip; Carrand, David; Gallagher, Philip M.

    2010-01-01

    Stretching prior to activity is universally accepted as an important way to improve performance and help prevent injury. Likewise, limited flexibility has been shown to decrease functional ability and predispose a person to injuries. Although this is commonly accepted, appropriate stretching for children and adolescents involved with sports and…

  17. Stretch Band Exercise Program

    Science.gov (United States)

    Skirka, Nicholas; Hume, Donald

    2007-01-01

    This article discusses how to use stretch bands for improving total body fitness and quality of life. A stretch band exercise program offers a versatile and inexpensive option to motivate participants to exercise. The authors suggest practical exercises that can be used in physical education to improve or maintain muscular strength and endurance,…

  18. Stretching: Does It Help?

    Science.gov (United States)

    Vardiman, Phillip; Carrand, David; Gallagher, Philip M.

    2010-01-01

    Stretching prior to activity is universally accepted as an important way to improve performance and help prevent injury. Likewise, limited flexibility has been shown to decrease functional ability and predispose a person to injuries. Although this is commonly accepted, appropriate stretching for children and adolescents involved with sports and…

  19. Cruciate ligament reflexes

    DEFF Research Database (Denmark)

    Krogsgaard, Michael R; Dyhre-Poulsen, Poul; Fischer-Rasmussen, Torsten

    2002-01-01

    The idea of muscular reflexes elicited from sensory nerves of the cruciate ligaments is more than 100 years old, but the existence of such reflexes has not been proven until the recent two decades. First in animal experiments, a muscular excitation could be elicited in the hamstrings when the ant...

  20. Reflexivity in qualitative research

    DEFF Research Database (Denmark)

    Evans, Adam Brian; Nistrup, Anne; Henderson, Hannah

    2017-01-01

    There has been something of a “reflexive shift” in sociological research. Sociological researchers are increasingly encouraged to be “present” within their work, and to recognize their own role in structuring the entire research process. One way to achieve this is through engagement in reflexive...... practice, that is, to reflect on our own values, beliefs, and biographies. It can be difficult to know exactly how a researcher should engage in these practices, however. Here, we discuss our reflexive practice in two case studies, both which utilized the same figurational theoretical framework...... Kingdom. Reflexive practice in both studies was affected by researcher biographies and by study design. In Study 1, both researchers were reasonably detached from the study context, the theoretical framework was in place from the very beginning, and reflexive practice was embedded in the study design...

  1. Reflexes from the lungs and airways: historical perspective.

    Science.gov (United States)

    Widdicombe, John

    2006-08-01

    Historical aspects of respiratory reflexes from the lungs and airways are reviewed, up until about 10 yr ago. For most of the 19th century, the possible reflex inputs into the "respiratory center," the position of which had been identified, were very speculative. There was little concept of reflex control of the pattern of breathing. Then, in 1868, Breuer published his paper on "The self-steering of respiration via the Nervus Vagus." For the first time this established the role of vagal inflation and deflation reflexes in determining the pattern of breathing. Head later extended Breuer's work, and Kratschmer laid a similar basis for reflexes from the nose and larynx. Then, 50-60 yr later, the development of the thermionic valve and the oscilloscope allowed recording action potentials from single nerve fibers in the vagus. In 1933, Adrian showed that slowly adapting pulmonary stretch receptors were responsible for the inflation reflex. Later, Knowlton and Larrabee described rapidly adapting receptors and showed that they mediated deep augmented breaths and the deflation reflex. Still later, it was established that rapidly adapting receptors were, at least in part, responsible for cough. In 1954, Paintal began his study of C-fiber receptors (J receptors), work greatly extended by the Coleridges. Since approximately 10 yr ago, when the field of this review stops, there has been an explosion of research on lung and airway receptors, many aspects of which are dealt with in other papers in this series.

  2. Etnography and Reflexivity

    Directory of Open Access Journals (Sweden)

    Mario Cardano

    2014-01-01

    Full Text Available This essay deals with a relevant and controversial topic – objectivity in ethnographic research. More specifically, I would like to examine how reflexive procedures, more precisely “reflexive account”, can increase the robustness of results gained through an ethnographic research. The essay is organized in five parts. I will start by giving a preliminary definition of the two key concepts which are at the center of the analysis – objectivity and reflexivity. I will then give a brief description of the epistemological framework in which the proposed conceptions of objectivity and reflexivity are located. Thirdly, I move on to consider the epistemic status of ethnographic research, and will emphasize that ethnographies are not just “theory-laden”, as many writers have stated, but also “praxis” or “procedure laden”. In other words, I will stress that it is not only theories which are inevitably embedded in research, influencing how observations can be made; much the same can also be said of the concrete research practices which contribute to determine the experience of the ethnographer and its representation in a text. Fourthly, I will discuss why it is useful to employ reflexive practices, and then immediately afterwards will illustrate the ways in which reflexive descriptions can contribute to greater objectivity of ethnographic accounts. In conclusion, I will discuss a number of objections which have been raised against this use of reflexivity.

  3. On Reflexive Data Models

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, S.

    2000-08-20

    An information system is reflexive if it stores a description of its current structure in the body of stored information and is acting on the base of this information. A data model is reflexive, if its language is meta-closed and can be used to build such a system. The need for reflexive data models in new areas of information technology applications is argued. An attempt to express basic notions related to information systems is made in the case when the system supports and uses meta-closed representation of the data.

  4. Polymer Stretching by Turbulence

    CERN Document Server

    Chertkov, M

    2000-01-01

    The stretching of a polymer chain by a large scale chaotic flow is considered. The steady state which emerges as a balance of the turbulent stretching and anharmonic resistance of the chain is quantitatively described, i.e. the dependency on the flow parameters (Lyapunov exponent statistics) and the chain characteristics (the number of beads and the inter-bead elastic potential) is made explicit. Implications for the drag reduction theory are discussed.

  5. Cortical excitability is not depressed in movement-modulated stretch response of human thumb flexor.

    Science.gov (United States)

    Wallace, C J; Miles, T S

    2001-08-01

    There is strong evidence that the predominant pathway of the long-latency stretch reflex for flexor pollicis longus crosses the motor cortex. This reflex response is diminished during active thumb movements. We tested the hypothesis that this could be due to a decrease in the excitability of the transcortical component during movement. During isometric, concentric and eccentric thumb movements, transcranial magnetic stimulation (TMS) of the motor cortex was given at a time when the reflex signal was traversing the motor cortex. TMS was also given earlier in separate runs when the signal was traversing the spinal cord under each of the three contractile conditions. The electromyogram was analysed for non-linear summation between stretch responses and the potential evoked by the cortical stimulus. The response to TMS alone was uniform across the three types of contraction, and the lack of cortical involvement in the short-latency reflex was confirmed. The TMS-evoked response summed in a non-linear manner with the long-latency reflex response, confirming that the excitability of the motor cortex was increased as the reflex signal passed through it. The long-latency response was markedly depressed during isotonic compared with isometric contractions. However, the non-linear summation was not greater during the isometric contractions. Thus, the depressed reflex responses during isotonic movements do not stem from reduced motor cortical responsiveness or afferent input to the transcortical pathway, and may instead reflect modulation of cutaneous reflexes during isotonic contractions.

  6. Interindividual differences in H reflex modulation during normal walking.

    Science.gov (United States)

    Simonsen, Erik B; Dyhre-Poulsen, Poul; Alkjaer, Tine; Aagaard, Per; Magnusson, S Peter

    2002-01-01

    Based on previous studies, at least two different types of soleus Hoffmann (H) reflex modulation were likely to be found during normal human walking. Accordingly, the aim of the present study was to identify different patterns of modulation of the soleus H reflex and to examine whether or not subjects with different H reflex modulation would exhibit different walking mechanics and different EMG activity. Fifteen subjects walked across two force platforms at 4.5 km/h (+/-10%) while the movements were recorded on video. The soleus H reflex and EMG activity were recorded separately during treadmill walking at 4.5 km/h. Using a two-dimensional analysis joint angles, angular velocities, accelerations, linear velocities and accelerations were calculated, and net joint moments about the ankle, knee and hip joint were computed by inverse dynamics from the video and force plate data. Six subjects (group S) showed a suppressed H reflex during the swing phase, and 9 subjects (group LS) showed increasing reflex excitability during the swing phase. The plantar flexor dominated moment about the ankle joint was greater for group LS. In contrast, the extensor dominated moment about the knee joint was greater for the S group. The hip joint moment was similar for the groups. The EMG activity in the vastus lateralis and anterior tibial muscles was greater prior to heel strike for the S group. These data indicate that human walking exhibits at least two different motor patterns as evaluated by gating of afferent input to the spinal cord, by EMG activity and by walking mechanics. Increasing H reflex excitability during the swing phase appears to protect the subject against unexpected perturbations around heel strike by a facilitated stretch reflex in the triceps surae muscle. Alternatively, in subjects with a suppressed H reflex in the swing phase the knee joint extensors seem to form the primary protection around heel strike.

  7. Supraspinal control of spinal reflex responses to body bending during different behaviours in lampreys.

    Science.gov (United States)

    Hsu, Li-Ju; Zelenin, Pavel V; Orlovsky, Grigori N; Deliagina, Tatiana G

    2017-02-01

    Spinal reflexes are substantial components of the motor control system in all vertebrates and centrally driven reflex modifications are essential to many behaviours, but little is known about the neuronal mechanisms underlying these modifications. To study this issue, we took advantage of an in vitro brainstem-spinal cord preparation of the lamprey (a lower vertebrate), in which spinal reflex responses to spinal cord bending (caused by signals from spinal stretch receptor neurons) can be evoked during different types of fictive behaviour. Our results demonstrate that reflexes observed during fast forward swimming are reversed during escape behaviours, with the reflex reversal presumably caused by supraspinal commands transmitted by a population of reticulospinal neurons. NMDA receptors are involved in the formation of these commands, which are addressed primarily to the ipsilateral spinal networks. In the present study the neuronal mechanisms underlying reflex reversal have been characterized for the first time. Spinal reflexes can be modified during different motor behaviours. However, our knowledge about the neuronal mechanisms underlying these modifications in vertebrates is scarce. In the lamprey, a lower vertebrate, body bending causes activation of intraspinal stretch receptor neurons (SRNs) resulting in spinal reflexes: activation of motoneurons (MNs) with bending towards either the contralateral or ipsilateral side (a convex or concave response, respectively). The present study had two main aims: (i) to investigate how these spinal reflexes are modified during different motor behaviours, and (ii) to reveal reticulospinal neurons (RSNs) transmitting commands for the reflex modification. For this purpose in in vitro brainstem-spinal cord preparation, RSNs and reflex responses to bending were recorded during different fictive behaviours evoked by supraspinal commands. We found that during fast forward swimming MNs exhibited convex responses. By contrast

  8. Free carboxylate stretching modes

    NARCIS (Netherlands)

    Oomens, J.; Steill, J. D.

    2008-01-01

    We report the first IR spectroscopic observation of carboxylate stretching modes in free space, i.e., in the complete absence of solvent or counterions. Gas-phase spectra of a series of benzoate anions have been recorded and compared to condensed-phase spectra, revealing the profound influence of th

  9. Corneomandibular reflex: Anatomical basis

    Directory of Open Access Journals (Sweden)

    Michele Pistacchi

    2015-01-01

    Full Text Available Corneomandibular reflex is a pathological phenomenon evident in cases of severe brainstem damage. It is considered to be a pathological exteroceptive reflex, associated with precentro bulbar tract lesions. The sign is useful in distinguishing central neurological injuries to metabolic disorders in acutely comatose patients, localizing lesions to the upper brainstem area, determining the depth of coma and its evolution, providing evidence of uncal or transtentorial herniation in acute cerebral hemisphere lesions, and it is a marker of supraspinal level impairment in amyotrophic lateral sclerosis and multiple sclerosis. This sign was evident in a patient with severe brain damage. We discuss the literature findings and its relevance in prognosis establishment.

  10. Comparison of the effects of hamstring stretching using proprioceptive neuromuscular facilitation with prior application of cryotherapy or ultrasound therapy.

    Science.gov (United States)

    Magalhães, Francisco Elezier Xavier; Junior, Arlindo Rodrigues de Mesquita; Meneses, Harnold's Tyson de Sousa; Moreira Dos Santos, Rayele Pricila; Rodrigues, Ezaine Costa; Gouveia, Samara Sousa Vasconcelos; Gouveia, Guilherme Pertinni de Morais; Orsini, Marco; Bastos, Victor Hugo do Vale; Machado, Dionis de Castro Dutra

    2015-05-01

    [Purpose] Stretching using proprioceptive neuromuscular facilitation involve physiological reflex mechanisms through submaximal contraction of agonists which activate Golgi organ, promoting the relaxation reflex. The aim of this study was to evaluate the effects of proprioceptive neuromuscular facilitation alone and with prior application of cryotherapy and thermotherapy on hamstring stretching. [Subjects and Methods] The sample comprised of 32 young subjects with hamstring retraction of the right limb. The subjects were randomly allocated to four groups: the control, flexibility PNF, flexibility PNF associated with cryotherapy, flexibility PNF in association with ultrasound therapy. [Results] After 12 stretching sessions, experimental groups showed significant improvements compared to the control group. Moreover, we did not find any significant differences among the experimental groups indicating PNF stretching alone elicits similar results to PNF stretching with prior administration of cryotherapy or thermotherapy. [Conclusion] PNF without other therapy may be a more practical and less expensive choice for clinical care.

  11. Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

    Science.gov (United States)

    2002

    This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

  12. Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

    Science.gov (United States)

    2002

    This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

  13. Spatial control of reflexes, posture and movement in normal conditions and after neurological lesions

    Directory of Open Access Journals (Sweden)

    Feldman Anatol G.

    2016-09-01

    Full Text Available Control of reflexes is usually associated with central modulation of their sensitivity (gain or phase-dependent inhibition and facilitation of their influences on motoneurons (reflex gating. Accumulated empirical findings show that the gain modulation and reflex gating are secondary, emergent properties of central control of spatial thresholds at which reflexes become functional. In this way, the system pre-determines, in a feedforward and task-specific way, where, in a spatial domain or a frame of reference, muscles are allowed to work without directly prescribing EMG activity and forces. This control strategy is illustrated by considering reflex adaptation to repeated muscle stretches in healthy subjects, a process associated with implicit learning and generalization. It has also been shown that spasticity, rigidity, weakness and other neurological motor deficits may have a common source – limitations in the range of spatial threshold control elicited by neural lesions.

  14. The Babinski reflex.

    Science.gov (United States)

    van Gijn, J

    1995-11-01

    The plantar response is a reflex that involves not only the toes, but all muscles that shorten the leg. In the newborn the synergy is brisk, involving all flexor muscles of the leg; these include the toe 'extensors', which also shorten the leg on contraction and therefore are flexors in a physiological sense. As the nervous system matures and the pyramidal tract gains more control over spinal motoneurones the flexion synergy becomes less brisk, and the toe 'extensors' are no longer part of it. The toes then often go down instead of up, as a result of a segmental reflex involving the small foot muscles and the overlying skin, comparable to the abdominal reflexes. With lesions of the pyramidal system, structural or functional, this segmental, downward response of the toes disappears, the flexion synergy may become disinhibited and the extensor hallucis longus muscle is again recruited into the flexion reflex of the leg: the sign of Babinski. A true Babinski sign denotes dysfunction of the pyramidal tract, and should be clearly distinguished from upgoing toes that do not belong to the flexion synergy of the leg. Correct interpretation of the plantar response depends only to a minor degree on the method or site of stimulation of the foot. It is therefore most important to assess the response in the entire leg.

  15. Reflexivity and social justice

    DEFF Research Database (Denmark)

    Maksimovic, Tijana; Jakobsen, Helle Nordentoft

    2017-01-01

    Career practitioners’ reflexive understanding of their professional role as change agents in career guidance and counselling practices has a major impact on how social justice can be achieved. This entitles an awareness of the way in which guidance and counselling practices are embedded in the co...

  16. Identification of Spinal Reflexes

    NARCIS (Netherlands)

    De Vlugt, E.

    2004-01-01

    Visco-elasticity of joints is important for the maintenance of the human body posture and can in two manners be regulated. By means of cocontraction of antagonistic muscle groups and by neural reflexive feedback of muscle length and muscle strength, measured both by means of sensors in the muscles.

  17. Changes in soleus H-reflex during walking in middle-aged, healthy subjects

    DEFF Research Database (Denmark)

    Raffalt, Peter C; Alkjær, Tine; Simonsen, Erik B

    2015-01-01

    and tibialis anterior muscles, and EMG/H-reflex gain were measured during 4-km/h treadmill walking. RESULTS: The normalized H-reflex amplitude was lower in the swing phase for the middle-aged group, and there was no difference in muscle activity. EMG/H-reflex gain did not differ between groups. CONCLUSIONS: H......-reflex amplitude during walking was affected by aging, and changes during the swing phase could be seen in the middle-aged subjects. Subdividing the 2 age groups into groups of facilitated or suppressed swing-phase H-reflex revealed that the H-reflex amplitude modulation pattern in the group with facilitated swing......INTRODUCTION: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. METHODS: The H-reflex amplitude, muscle activity (EMG) of the soleus...

  18. Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.

    Science.gov (United States)

    Makihara, Yukiko; Segal, Richard L; Wolpaw, Jonathan R; Thompson, Aiko K

    2014-09-15

    In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion. Copyright © 2014 the American Physiological Society.

  19. Spinal reflexes in brain death.

    Science.gov (United States)

    Beckmann, Yesim; Çiftçi, Yeliz; Incesu, Tülay Kurt; Seçil, Yaprak; Akhan, Galip

    2014-12-01

    Spontaneous and reflex movements have been described in brain death and these unusual movements might cause uncertainties in diagnosis. In this study we evaluated the presence of spinal reflexes in patients who fulfilled the criteria for brain death. Thirty-two (22 %) of 144 patients presented unexpected motor movements spontaneously or during examinations. These patients exhibited the following signs: undulating toe, increased deep tendon reflexes, plantar responses, Lazarus sign, flexion-withdrawal reflex, facial myokymia, neck-arm flexion, finger jerks and fasciculations. In comparison, there were no significant differences in age, sex, etiology of brain death and hemodynamic laboratory findings in patients with and without reflex motor movement. Spinal reflexes should be well recognized by physicians and it should be born in mind that brain death can be determined in the presence of spinal reflexes.

  20. Mentalis muscle related reflexes.

    Science.gov (United States)

    Gündüz, Ayşegül; Uyanık, Özlem; Ertürk, Özdem; Sohtaoğlu, Melis; Kızıltan, Meral Erdemir

    2016-05-01

    The mentalis muscle (MM) arises from the incisive fossa of the mandible, raises and protrudes the lower lip. Here, we aim to characterize responses obtained from MM by supraorbital and median electrical as well as auditory stimuli in a group of 16 healthy volunteers who did not have clinical palmomental reflex. Reflex activities were recorded from the MM and orbicularis oculi (O.oc) after supraorbital and median electrical as well as auditory stimuli. Response rates over MM were consistent after each stimulus, however, mean latencies of MM response were longer than O.oc responses by all stimulation modalities. Shapes and amplitudes of responses from O.oc and MM were similar. Based on our findings, we may say that MM motoneurons have connections with trigeminal, vestibulocochlear and lemniscal pathways similar to other facial muscles and electrophysiological recording of MM responses after electrical and auditory stimulation is possible in healthy subjects.

  1. Reflex epilepsy: a review

    Directory of Open Access Journals (Sweden)

    Karim Nikkhah

    2017-01-01

    Full Text Available Interesting phenomena of reflex epileptic syndromes are characterized by epileptic seizures each one induced by specific stimulus with a variety of types. Simple triggers, which lead to seizures within seconds, are of sensory type (most commonly visual, most rarely tactile or proprioceptive stimuli. Complex triggers, which are mostly of cognitive type such as praxis, reading, talking, and music, usually induce the epileptic event within minutes. It should differ from what most epileptic patients report as provocative precipitants for seizures (such as emotional stress, fatigue, fever, sleep deprivation, alcohol, and menstrual cycle. The identification of a specific trigger is not only important for patients or their parents to avoid seizures, but also it might help neurologists to choose the most effective antiepileptic drug for each case. In addition, research in this area may possibly reveal some underlying pathophysiology of epileptic phenomena in the brain.In this review, we briefly introduce reported reflex epileptic seizures, their clinical features and management.

  2. Brand, Brand Stretching, and Brand Stretching Plan for JAC

    OpenAIRE

    Chen, Lei

    2012-01-01

    With the consistent crisis of world economic, companies are encountering problems with their expansion. Introducing all new brands for expanding is hard to be accepted due to the high level of costs and risks. Using brand stretching as companies’ expansion strategy efficiently reduces the costs and risks today. Therefore, getting clear about brand stretching seems quite important for most companies nowadays. The objectives of this thesis is introducing brand stretching theory and making a...

  3. Brand, Brand Stretching, and Brand Stretching Plan for JAC

    OpenAIRE

    Chen, Lei

    2012-01-01

    With the consistent crisis of world economic, companies are encountering problems with their expansion. Introducing all new brands for expanding is hard to be accepted due to the high level of costs and risks. Using brand stretching as companies’ expansion strategy efficiently reduces the costs and risks today. Therefore, getting clear about brand stretching seems quite important for most companies nowadays. The objectives of this thesis is introducing brand stretching theory and making a...

  4. Adductor T reflex abnormalities in patients with decreased patellar reflexes.

    Science.gov (United States)

    Tataroglu, Cengiz; Deneri, Ersin; Ozkul, Ayca; Sair, Ahmet; Yaycioglu, Soner

    2009-08-01

    The adductor reflex (AR) is a tendon reflex that has various features that differ from other tendon reflexes. This reflex was tested in different disorders presenting with diminished patellar reflexes such as diabetic lumbosacral radiculoplexus neuropathy (DLRPN), L2-L4 radiculopathy, and distal symmetric diabetic neuropathy (diabetic PNP). The AR and crossed-AR (elicited by tapping the contralateral patellar tendon) were recorded using concentric needle electrodes. Additionally, the patellar T reflex (vm-TR) and vastus medialis H reflex (vm-HR) were recorded using surface electrodes. AR was recorded in only one out of eight patients with DLRPN, but it was recorded in 21 out of 22 patients with L2-L4 radiculopathy (95.5%). Of these reflexes, only AR showed prolonged latency in the L2-L4 radiculopathy group. The latencies of AR, vm-TR, and vm-HR were prolonged in patients with diabetic PNP. We conclude that AR can be useful in the differential diagnosis of some lower motor neuron disorders that present with patellar reflex disturbance. Muscle Nerve 40: 264-270, 2009.

  5. Stretching cells with DEAs

    Science.gov (United States)

    Akbari, S.; Rosset, S.; Shea, H. R.

    2012-04-01

    Biological cells regulate their biochemical behavior in response to mechanical stress present in their organism. Most of the available cell cultures designed to study the effect of mechanical stimuli on cells are cm2 area, far too large to monitor single cell response or have a very low throughput. We have developed two sets of high throughput single cell stretcher devices based on dielectric elastomer microactuators to stretch groups of individual cells with various strain levels in a single experiment. The first device consists of an array of 100 μm x 200 μm actuators on a non-stretched PDMS membrane bonded to a Pyrex chip, showing up to 4.7% strain at the electric field of 96 V/μm. The second device contains an array of 100 μm x 100 μm actuators on a 160% uniaxially prestretched PDMS membrane suspended over a frame. 37% strain is recorded at the nominal electric field of 114 V/μm. The performance of these devices as a cell stretcher is assessed by comparing their static and dynamic behavior.

  6. Stretching the Border

    DEFF Research Database (Denmark)

    Horstmann, Alexander

    2014-01-01

    In this paper, I hope to add a complementary perspective to James Scott’s recent work on avoidance strategies of subaltern mountain people by focusing on what I call the refugee public. The educated Karen elite uses the space of exile in the Thai borderland to reconstitute resources and to re......-enter Karen state in Eastern Burma as humanitarians, providing medical, educational resources and help to document human rights violations and do advocacy work. In addition, local missionaries and faith-based groups also use the corridor to spread the word of God. I argue that Karen humanitarian community......-based organizations succeed to stretch the border by establishing a firm presence that is supported by the international humanitarian economy in the refugee camps in Northwestern Thailand....

  7. Submaximal fatigue of the hamstrings impairs specific reflex components and knee stability.

    Science.gov (United States)

    Melnyk, Mark; Gollhofer, Albert

    2007-05-01

    Rupture of the anterior cruciate ligament (ACL) is one of the most serious sports-related injuries and requires long recovery time. The quadriceps and hamstring muscles are functionally important to control stability of the knee joint complex. Fatigue, however, is an important factor that may influence stabilizing control and thus cause ACL injuries. The objective of this study was therefore to assess how submaximal fatigue exercises of the hamstring muscles affect anterior tibial translation as a direct measure of knee joint stability. While 15 test participants were standing upright with the knees in 30 degrees of flexion, anterior tibial translation was induced by a force of 315 N. Two linear potentiometers placed on the tibial tuberosity and the patella recorded tibial motion relative to the femur. Reflex latencies and neuromuscular hamstring activity were determined using surface electromyography (EMG). Muscle fatigue produced a significant longer latency for the monosynaptic reflex latencies, whereas no differences in the latencies of the medium latency component were found. Fatigue significantly reduced EMG amplitudes of the short and medium latency components. These alterations were in line with significantly increased anterior tibial translation. Our results suggest that hamstring fatigue is effectively associated with mechanical loss of knee stability. This decrease in joint stability may at least in part explain higher risk of ACL injury, especially in fatigued muscles. Furthermore, we discuss why the present findings indicate that reduced motor activity rather than the extended latency of the first hamstring response is the reason for possible failure.

  8. Too Busy for Reflexivity?

    DEFF Research Database (Denmark)

    Ratner, Helene

    highlighted non-symmetric relationships between observer and observed and accused the academic text of enacting a realist genre, concealing the relativism entailed in textual production (Clifford and Marcus 1986, Woolgar 1988, Ashmore 1989). On the other hand, the reflexivity program produced fears...... of a “corrosive relativism in which everything is but a more or less clever expression of opinion” (Geertz 1988:2, 3) and it has suffered the little flattering accusations of piling "layer upon layer of self-consciousness to no avail" (Latour 1988:170) with little “interest [for] … theoretically ambitious...

  9. Monosynaptic glutamatergic activation of locus coeruleus and other lower brainstem noradrenergic neurons by the C1 cells in mice.

    Science.gov (United States)

    Holloway, Benjamin B; Stornetta, Ruth L; Bochorishvili, Genrieta; Erisir, Alev; Viar, Kenneth E; Guyenet, Patrice G

    2013-11-27

    The C1 neurons, located in the rostral ventrolateral medulla (VLM), are activated by pain, hypotension, hypoglycemia, hypoxia, and infection, as well as by psychological stress. Prior work has highlighted the ability of these neurons to increase sympathetic tone, hence peripheral catecholamine release, probably via their direct excitatory projections to sympathetic preganglionic neurons. In this study, we use channelrhodopsin-2 (ChR2) optogenetics to test whether the C1 cells are also capable of broadly activating the brain's noradrenergic system. We selectively expressed ChR2(H134R) in rostral VLM catecholaminergic neurons by injecting Cre-dependent adeno-associated viral vectors into the brain of adult dopamine-β-hydroxylase (DβH)(Cre/0) mice. Most ChR2-expressing VLM neurons (75%) were immunoreactive for phenylethanolamine N-methyl transferease, thus were C1 cells, and most of the ChR2-positive axonal varicosities were immunoreactive for vesicular glutamate transporter-2 (78%). We produced light microscopic evidence that the axons of rostral VLM (RVLM) catecholaminergic neurons contact locus coeruleus, A1, and A2 noradrenergic neurons, and ultrastructural evidence that these contacts represent asymmetric synapses. Using optogenetics in tissue slices, we show that RVLM catecholaminergic neurons activate the locus coeruleus as well as A1 and A2 noradrenergic neurons monosynaptically by releasing glutamate. In conclusion, activation of RVLM catecholaminergic neurons, predominantly C1 cells, by somatic or psychological stresses has the potential to increase the firing of both peripheral and central noradrenergic neurons.

  10. Retrograde monosynaptic tracing reveals the temporal evolution of inputs onto new neurons in the adult dentate gyrus and olfactory bulb

    Science.gov (United States)

    Deshpande, Aditi; Bergami, Matteo; Ghanem, Alexander; Conzelmann, Karl-Klaus; Lepier, Alexandra; Götz, Magdalena; Berninger, Benedikt

    2013-01-01

    Identifying the connectome of adult-generated neurons is essential for understanding how the preexisting circuitry is refined by neurogenesis. Changes in the pattern of connectivity are likely to control the differentiation process of newly generated neurons and exert an important influence on their unique capacity to contribute to information processing. Using a monosynaptic rabies virus-based tracing technique, we studied the evolving presynaptic connectivity of adult-generated neurons in the dentate gyrus (DG) of the hippocampus and olfactory bulb (OB) during the first weeks of their life. In both neurogenic zones, adult-generated neurons first receive local connections from multiple types of GABAergic interneurons before long-range projections become established, such as those originating from cortical areas. Interestingly, despite fundamental similarities in the overall pattern of evolution of presynaptic connectivity, there were notable differences with regard to the development of cortical projections: although DG granule neuron input originating from the entorhinal cortex could be traced starting only from 3 to 5 wk on, newly generated neurons in the OB received input from the anterior olfactory nucleus and piriform cortex already by the second week. This early glutamatergic input onto newly generated interneurons in the OB was matched in time by the equally early innervations of DG granule neurons by glutamatergic mossy cells. The development of connectivity revealed by our study may suggest common principles for incorporating newly generated neurons into a preexisting circuit. PMID:23487772

  11. [Laryngeal and larynx-associated reflexes].

    Science.gov (United States)

    Ptok, M; Kühn, D; Miller, S; Jungheim, M; Schroeter, S

    2016-06-01

    The laryngeal adductor reflex and the pharyngoglottal closure reflex protect the trachea and lower respiratory tract against the entrance of foreign material. The laryngeal expiration reflex and the cough reflex serve to propel foreign material, which has penetrated in the cranial direction. The inspiration reflex, the sniff reflex, and the swallowing reflex are further larynx-associated reflexes. In patients with dysphagia the laryngeal adductor reflex can be clinically tested with air pulses. The water swallow test serves to show the integrity of the cough reflex. The sniff reflex is useful to test the abduction function of the vocal folds. Future studies should address laryngeal reflexes more specifically, both for a better understanding of these life-supporting mechanisms and to improve diagnostic procedures in patients with impaired laryngeal function.

  12. Patterning of somatosympathetic reflexes

    Science.gov (United States)

    Kerman, I. A.; Yates, B. J.

    1999-01-01

    In a previous study, we reported that vestibular nerve stimulation in the cat elicits a specific pattern of sympathetic nerve activation, such that responses are particularly large in the renal nerve. This patterning of vestibulosympathetic reflexes was the same in anesthetized and decerebrate preparations. In the present study, we report that inputs from skin and muscle also elicit a specific patterning of sympathetic outflow, which is distinct from that produced by vestibular stimulation. Renal, superior mesenteric, and lumbar colonic nerves respond most strongly to forelimb and hindlimb nerve stimulation (approximately 60% of maximal nerve activation), whereas external carotid and hypogastric nerves were least sensitive to these inputs (approximately 20% of maximal nerve activation). In contrast to vestibulosympathetic reflexes, the expression of responses to skin and muscle afferent activation differs in decerebrate and anesthetized animals. In baroreceptor-intact animals, somatosympathetic responses were strongly attenuated (to 150 mmHg. These findings demonstrate that different types of somatic inputs elicit specific patterns of sympathetic nerve activation, presumably generated through distinct neural circuits.

  13. Proprioceptive reflexes and neurological disorders

    NARCIS (Netherlands)

    Schouten, A.C.

    2004-01-01

    Proprioceptive reflexes play an important role during the control of movement and posture. Disturbed modulation of proprioceptive reflexes is often suggested as the cause for the motoric features present in neurological disorders. In this thesis methods are developed and evaluated to quantify propri

  14. AMPUTATION AND REFLEX SYMPATHETIC DYSTROPHY

    NARCIS (Netherlands)

    GEERTZEN, JHB; EISMA, WH

    Reflex sympathetic dystrophy is a chronic pain syndrome characterized by chronic burning pain, restricted range of motion, oedema and vasolability. Patients are difficult to treat and the prognosis is very often poor. This report emphasizes that an amputation in case of a reflex sympathetic

  15. Stretching for prevention of Achilles tendon injuries: a review of the literature.

    Science.gov (United States)

    Park, Don Young; Chou, Loretta

    2006-12-01

    Professional and recreational athletes commonly perform pre-exercise stretching to prevent musculoskeletal injuries. Little definitive evidence exists that clearly demonstrates the efficacy of stretching in reducing injury. Achilles tendon injuries are among the most common injuries affecting active individuals in the United States today. Clinicians commonly recommend stretching the Achilles tendon without concrete scientific evidence to support such a claim. Few studies have addressed the effect of stretching in Achilles tendon injuries, and it is unclear if the conclusions made for musculoskeletal injuries can be applied to the Achilles tendon. Biomechanical studies of the Achilles tendon and measurements of the tendon's reflex activity have demonstrated possible mechanisms for the potential benefit of stretching, including load-induced hypertrophy and increased tendon tensile strength. Recent prospective studies have contended that reductions in plantarflexor strength and increases in ankle dorsiflexion range of motion from stretching the Achilles tendon may increase the risk of injury. Studies examining stretching in injury prevention, the biomechanical properties of injuries to the Achilles tendon were compiled and reviewed. Although many theories have been published regarding the potential benefits and limitations of stretching, few studies have been able to definitively demonstrate its utility in injury prevention.

  16. Reflexive Aero Structures for Enhanced Survivability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) proposes to develop an advanced reflexive structure system to increase the survivability of aerostructures. This reflexive...

  17. Acoustic reflex and general anaesthesia.

    Science.gov (United States)

    Farkas, Z

    1983-01-01

    Infant and small children are not always able to cooperate in impedance measurements. For this reason it was decided, -in special cases, -to perform acoustic reflex examination under general anaesthesia. The first report on stapedius reflex and general anaesthesia was published by Mink et al. in 1981. Under the effect of Tiobutabarbital, Propanidid and Diazepam there is no reflex response. Acoustic reflex can be elicited with Ketamin-hydrochlorid and Alphaxalone-alphadolone acetate narcosis. The reflex threshold remains unchanged and the amplitude of muscle contraction is somewhat increased. The method was used: 1. to assess the type and degree of hearing loss in children with cleft palate and/or lip prior to surgery. 2. to exclude neuromuscular disorders with indication of pharyngoplasties. 3. to quantify hearing level in children--mostly multiply handicapped--with retarded speech development. The results of Behavioral Observation and Impedance Audiometry are discussed and evaluated.

  18. [Reflex seizures, cinema and television].

    Science.gov (United States)

    Olivares-Romero, Jesús

    2015-12-16

    In movies and television series are few references to seizures or reflex epilepsy even though in real life are an important subgroup of total epileptic syndromes. It has performed a search on the topic, identified 25 films in which they appear reflex seizures. Most seizures observed are tonic-clonic and visual stimuli are the most numerous, corresponding all with flashing lights. The emotions are the main stimuli in higher level processes. In most cases it is not possible to know if a character suffers a reflex epilepsy or suffer reflex seizures in the context of another epileptic syndrome. The main conclusion is that, in the movies, the reflex seizures are merely a visual reinforcing and anecdotal element without significant influence on the plot.

  19. Effect of reversible dorsal cold block on the persistence of inhibition generated by spinal reflexes.

    Science.gov (United States)

    Miller, J F; Paul, K D; Jiang, B; Rymer, W Z; Heckman, C J

    1995-01-01

    The effects of bilateral focal cooling of dorsolateral thoracic spinal cord on segmental reflex pathways to the triceps surae muscles were assessed in decerebrate cats from the reflex forces produced by single shocks or trains of electrical stimuli applied to the ipsilateral caudal cutaneous sural and the contralateral tibial nerves. The validity of the dorsal cold block technique as a substitute for acute surgical dorsal hemisection was established by showing that focal cooling reliably reproduced the stretch-induced "clasp knife" inhibition of triceps surae reflexive force seen following dorsal hemisection. Under control (warm) conditions, the inhibitory components of electrically evoked ipsilateral sural and contralateral tibial reflexes faded rapidly during sustained trains, with a resultant production of large-amplitude reflex force as measured from either the entire triceps surae or from the medial gastrocnemius muscle alone. Dorsal cold block greatly reduced the amplitude of reflexive force evoked by sustained electrical stimulation of either nerve. Indeed, the cold block completely reversed the sign of train-evoked reflexes to a net inhibition of reflex force output in one-half of the sural and one-half of the contralateral tibial stimulation experiments. Peak transient forces evoked by single shocks to the sural or contralateral tibial nerves were also sometimes reduced, but this result was more variable than for prolonged nerve stimulation. The persistence of activity in segmental inhibitory pathways during dorsal cold block, as indicated by instances of reflex sign reversal, suggests that descending bulbospinal pathways traversing the dorsolateral funiculi may be responsible for "fading" of segmental inhibitory reflex components in decerebrate cats with intact spinal cords during sustained afferent input. The possibility that the enhanced magnitude and duration of segmental inhibition during cold block will increase the likelihood of disruption of the

  20. To stretch or not to stretch: the role of stretching in injury prevention and performance.

    Science.gov (United States)

    McHugh, M P; Cosgrave, C H

    2010-04-01

    Stretching is commonly practiced before sports participation; however, effects on subsequent performance and injury prevention are not well understood. There is an abundance of literature demonstrating that a single bout of stretching acutely impairs muscle strength, with a lesser effect on power. The extent to which these effects are apparent when stretching is combined with other aspects of a pre-participation warm-up, such as practice drills and low intensity dynamic exercises, is not known. With respect to the effect of pre-participation stretching on injury prevention a limited number of studies of varying quality have shown mixed results. A general consensus is that stretching in addition to warm-up does not affect the incidence of overuse injuries. There is evidence that pre-participation stretching reduces the incidence of muscle strains but there is clearly a need for further work. Future prospective randomized studies should use stretching interventions that are effective at decreasing passive resistance to stretch and assess effects on subsequent injury incidence in sports with a high prevalence of muscle strains.

  1. Modulation of reflex responses in hand muscles during rhythmical finger tasks in a subject with writer's cramp.

    Science.gov (United States)

    Xia, Ruiping; Bush, Brian M H

    2007-03-01

    The objective of this study was to examine phase- and task-dependent modulation of stretch reflexes during repetitive finger movements in writer's cramp, and compare them with normal controls from our previous study. A subject with writer's cramp conducted two rhythmic tasks, index finger abduction (RFA) and a pen-squeezing (RPS) task akin to handwriting. Stretch reflexes were evoked by mechanical perturbations at random phases of each task. Surface electromyograms (EMG) were recorded from two hand muscles, first dorsal interosseous (FDI) and flexor digitorum superficialis (FDS). The reflex response and background EMG activity of each muscle were modulated in a phase-dependent manner in both tasks. However, they varied largely in phase during the RFA task, but in approximately inverse phase-relationship during RPS. Reflex sensitivity, as represented by the slope of the linear regression between response and background, was much lower for both muscles in the 'writing' task (RPS) than in the RFA task with its positively correlated responses. These phase- and task-related modulation patterns differed dramatically from those observed in our control subjects, where reflex responses were modulated largely in phase with background activity and reflex sensitivity was much higher, particularly in FDI during RFA and FDS during RPS. The altered reflex modulation patterns in writer's cramp may reflect deficiencies of integration of proprioceptive afferent inputs and reduced inhibition at cortical and spinal levels during writing performance. Results from this case study support clinically identified task-specific feature of focal hand dystonia.

  2. Stretch-minimising stream surfaces

    KAUST Repository

    Barton, Michael

    2015-05-01

    We study the problem of finding stretch-minimising stream surfaces in a divergence-free vector field. These surfaces are generated by motions of seed curves that propagate through the field in a stretch minimising manner, i.e., they move without stretching or shrinking, preserving the length of their arbitrary arc. In general fields, such curves may not exist. How-ever, the divergence-free constraint gives rise to these \\'stretch-free\\' curves that are locally arc-length preserving when infinitesimally propagated. Several families of stretch-free curves are identified and used as initial guesses for stream surface generation. These surfaces are subsequently globally optimised to obtain the best stretch-minimising stream surfaces in a given divergence-free vector field. Our algorithm was tested on benchmark datasets, proving its applicability to incompressible fluid flow simulations, where our stretch-minimising stream surfaces realistically reflect the flow of a flexible univariate object. © 2015 Elsevier Inc. All rights reserved.

  3. Monosynaptic Glutamatergic Activation of Locus Coeruleus and Other Lower Brainstem Noradrenergic Neurons by the C1 Cells in Mice

    Science.gov (United States)

    Holloway, Benjamin B.; Stornetta, Ruth L.; Bochorishvili, Genrieta; Erisir, Alev; Viar, Kenneth E.

    2013-01-01

    The C1 neurons, located in the rostral ventrolateral medulla (VLM), are activated by pain, hypotension, hypoglycemia, hypoxia, and infection, as well as by psychological stress. Prior work has highlighted the ability of these neurons to increase sympathetic tone, hence peripheral catecholamine release, probably via their direct excitatory projections to sympathetic preganglionic neurons. In this study, we use channelrhodopsin-2 (ChR2) optogenetics to test whether the C1 cells are also capable of broadly activating the brain's noradrenergic system. We selectively expressed ChR2(H134R) in rostral VLM catecholaminergic neurons by injecting Cre-dependent adeno-associated viral vectors into the brain of adult dopamine-β-hydroxylase (DβH)Cre/0 mice. Most ChR2-expressing VLM neurons (75%) were immunoreactive for phenylethanolamine N-methyl transferease, thus were C1 cells, and most of the ChR2-positive axonal varicosities were immunoreactive for vesicular glutamate transporter-2 (78%). We produced light microscopic evidence that the axons of rostral VLM (RVLM) catecholaminergic neurons contact locus coeruleus, A1, and A2 noradrenergic neurons, and ultrastructural evidence that these contacts represent asymmetric synapses. Using optogenetics in tissue slices, we show that RVLM catecholaminergic neurons activate the locus coeruleus as well as A1 and A2 noradrenergic neurons monosynaptically by releasing glutamate. In conclusion, activation of RVLM catecholaminergic neurons, predominantly C1 cells, by somatic or psychological stresses has the potential to increase the firing of both peripheral and central noradrenergic neurons. PMID:24285886

  4. Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude

    Directory of Open Access Journals (Sweden)

    Ferris Daniel P

    2010-07-01

    Full Text Available Abstract Background To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by ~35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H- reflex responses during powered versus unpowered walking. Methods We tested soleus H-reflex responses in neurologically intact subjects (n=8 that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered, then with power (powered, and finally without power again (second unpowered. We also collected joint kinematics and electromyography. Results When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG activation (27-48% and had concomitant reductions in H-reflex amplitude (12-24% compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. Conclusion These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance

  5. Acute Muscle Stretching and Shoulder Position Sense

    OpenAIRE

    Björklund, Martin; Djupsjöbacka, Mats; Crenshaw, Albert G.

    2006-01-01

    Context: Stretching is common among athletes as a potential method for injury prevention. Stretching-induced changes in the muscle spindle properties are a suggested mechanism, which may imply reduced proprioception after stretching; however, little is known of this association.

  6. The vestibulosympathetic reflex in humans: neural interactions between cardiovascular reflexes

    Science.gov (United States)

    Ray, Chester A.; Monahan, Kevin D.

    2002-01-01

    1. Over the past 5 years, there has been emerging evidence that the vestibular system regulates sympathetic nerve activity in humans. We have studied this issue in humans by using head-down rotation (HDR) in the prone position. 2. These studies have clearly demonstrated increases in muscle sympathetic nerve activity (MSNA) and calf vascular resistance during HDR. These responses are mediated by engagement of the otolith organs and not the semicircular canals. 3. However, differential activation of sympathetic nerve activity has been observed during HDR. Unlike MSNA, skin sympathetic nerve activity does not increase with HDR. 4. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes (i.e. barorereflexes and skeletal muscle reflexes) has shown an additive interaction for MSNA. 5. The additive interaction between the baroreflexes and vestibulosympathetic reflex suggests that the vestibular system may assist in defending against orthostatic challenges in humans by elevating MSNA beyond that of the baroreflexes. 6. In addition, the further increase in MSNA via otolith stimulation during isometric handgrip, when arterial pressure is elevated markedly, indicates that the vestibulosympathetic reflex is a powerful activator of MSNA and may contribute to blood pressure and flow regulation during dynamic exercise. 7. Future studies will help evaluate the importance of the vestibulosympathetic reflex in clinical conditions associated with orthostatic hypotension.

  7. Hydraulic fracture during epithelial stretching

    Science.gov (United States)

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier

    2015-03-01

    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells’ cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here, we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression manoeuvres. After pressure equilibration, cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics.

  8. H-reflex up-conditioning encourages recovery of EMG activity and H-reflexes after sciatic nerve transection and repair in rats.

    Science.gov (United States)

    Chen, Yi; Wang, Yu; Chen, Lu; Sun, Chenyou; English, Arthur W; Wolpaw, Jonathan R; Chen, Xiang Yang

    2010-12-01

    Operant conditioning of the spinal stretch reflex or its electrical analog, the H-reflex, produces spinal cord plasticity and can thereby affect motoneuron responses to primary afferent input. To explore whether this conditioning can affect the functional outcome after peripheral nerve injury, we assessed the effect of up-conditioning soleus (SOL) H-reflex on SOL and tibialis anterior (TA) function after sciatic nerve transection and repair. Sprague Dawley rats were implanted with EMG electrodes in SOL and TA and stimulating cuffs on the posterior tibial nerve. After control data collection, the sciatic nerve was transected and repaired and the rat was exposed for 120 d to continued control data collection (TC rats) or SOL H-reflex up-conditioning (TU rats). At the end of data collection, motoneurons that had reinnervated SOL and TA were labeled retrogradely. Putative primary afferent terminals [i.e., terminals containing vesicular glutamate transporter-1 (VGLUT1)] on SOL motoneurons were studied immunohistochemically. SOL (and probably TA) background EMG activity recovered faster in TU rats than in TC rats, and the final recovered SOL H-reflex was significantly larger in TU than in TC rats. TU and TC rats had significantly fewer labeled motoneurons and higher proportions of double-labeled motoneurons than untransected rats. VGLUT1 terminals were significantly more numerous on SOL motoneurons of TU than TC rats. Combined with the larger H-reflexes in TU rats, this anatomical finding supports the hypothesis that SOL H-reflex up-conditioning strengthened primary afferent reinnervation of SOL motoneurons. These results suggest that H-reflex up-conditioning may improve functional recovery after nerve injury and repair.

  9. Oculocardiac reflex during strabismus surgery

    Directory of Open Access Journals (Sweden)

    Mehryar Taghavi Gilani

    2016-12-01

    Full Text Available The activation of oculucardiac reflex (OCR is common during the strabismus surgeries. OCR is known as a trigemino-vagal reflex, which leads to the various side effects including bradycardia, tachycardia, arrhythmia, or in some cases cardiac arrest. This reflex could be activated during intraorbital injections, hematomas, and mechanical stimulation of eyeball and extraocular muscles surgeries. The incidence of OCR varies in a wide range, from 14% to 90%, that depends on anesthetic strategy and drug used for the surgery. The efficacy of various anticholinergic and anesthetic agents on declining the OCR reflex has been evaluated in different studies, especially in children. Although the detection of OCR goes back to 1908, its exact effect is not well recognized during strabismus surgery. In this review, we aimed to summarize the studies investigated the efficacy and potential of various anesthetic medications on inhibiting the OCR in children undergoing strabismus surgery.

  10. Management of Reflex Anoxic Seizures

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-10-01

    Full Text Available Investigators at the Roald Dahl EEG Unit, Alder Hey Children’s NHS Foundation, Liverpool, UK, review the definition, pathophysiology, clinical presentation, and management of reflex anoxic seizures (RAS in children.

  11. SYSTEM REFLEXIVE STRATEGIC MARKETING MANAGEMENT

    Directory of Open Access Journals (Sweden)

    A. Dligach

    2013-10-01

    Full Text Available This article reviews the System Reflexive paradigm of strategic marketing management, being based on the alignment of strategic economic interests of stakeholders, specifically, enterprise owners and hired managers, and consumers. The essence of marketing concept of management comes under review, along with the strategic management approaches to business, buildup and alignment of economic interests of business stakeholders. A roadmap for resolving the problems of modern marketing is proposed through the adoption of System Reflexive marketing theory.

  12. SYSTEM REFLEXIVE STRATEGIC MARKETING MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Andrii A. DLIGACH

    2012-07-01

    Full Text Available This article reviews the System Reflexive paradigm of strategic marketing management, being based on the alignment of strategic economic interests of stakeholders, specifically, enterprise owners and hired managers, and consumers. The essence of marketing concept of management comes under review, along with the strategic management approaches to business, buildup and alignment of economic interests of business stakeholders. A roadmap for resolving the problems of modern marketing is proposed through the adoption of System Reflexive marketing theory.

  13. Muscle and reflex changes with varying joint angle in hemiparetic stroke

    Directory of Open Access Journals (Sweden)

    Alibiglou Laila

    2008-02-01

    Full Text Available Abstract Background Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint. Methods Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM. Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls. Results Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position. Conclusion In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated. Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects

  14. Atomic Stretch: Optimally bounded real-time stretching and beyond

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll

    2016-01-01

    Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color-modification, co......Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color...

  15. Long-latency reflexes account for limb biomechanics through several supraspinal pathways

    Directory of Open Access Journals (Sweden)

    Isaac Louis Kurtzer

    2015-01-01

    Full Text Available Accurate control of body posture is enforced by a multitude of corrective actions operating over a range of time scales. The earliest correction is the short-latency reflex which occurs between 20-45 ms following a sudden displacement of the limb and is generated entirely by spinal circuits. In contrast, voluntary reactions are generated by a highly distributed network but at a significantly longer delay after stimulus onset (greater than 100 ms. Between these two epochs is the long-latency reflex (around 50-100 ms which but acts more rapidly than of voluntary reactions but shares some supraspinal pathways and functional capabilities. In particular, the long-latency reflex accounts for the arm’s biomechanical properties rather than only responding to local muscle stretch like the short-latency reflex. This paper will review how the long-latency reflex accounts for the arm’s biomechanical properties and the supraspinal pathways supporting this ability. Relevant experimental paradigms include clinical studies, non-invasive brain stimulation, neural recordings in monkeys, and human behavioral studies. The sum of this effort indicates that primary motor cortex and reticular formation contribute to the the long-latency reflex either by generating or scaling its structured response appropriate for the arm’s biomechanics whereas the cerebellum scales the magnitude of the feedback response. Additional putative pathways are discussed as well as potential research lines.

  16. Proprioceptive neuropathy affects normalization of the H-reflex by exercise after spinal cord injury.

    Science.gov (United States)

    Ollivier-Lanvin, Karen; Keeler, Benjamin E; Siegfried, Rachel; Houlé, John D; Lemay, Michel A

    2010-01-01

    The H-reflex habituates at relatively low frequency (10 Hz) stimulation in the intact spinal cord, but loss of descending inhibition resulting from spinal cord transection reduces this habituation. There is a return towards a normal pattern of low-frequency habituation in the reflex activity with cycling exercise of the affected hind limbs. This implies that repetitive passive stretching of the muscles in spinalized animals and the accompanying stimulation of large (Group I and II) proprioceptive fibers has modulatory effects on spinal cord reflexes after injury. To test this hypothesis, we induced pyridoxine neurotoxicity that preferentially affects large dorsal root ganglia neurons in intact and spinalized rats. Pyridoxine or saline injections were given twice daily (IP) for 6 weeks and half of the spinalized animals were subjected to cycling exercise during that period. After 6 weeks, the tibial nerve was stimulated electrically and recordings of M and H waves were made from interosseous muscles of the hind paw. Results show that pyridoxine treatment completely eliminated the H-reflex in spinal intact animals. In contrast, transection paired with pyridoxine treatment resulted in a reduction of the frequency-dependent habituation of the H-reflex that was not affected by exercise. These results indicate that normal Group I and II afferent input is critical to achieve exercise-based reversal of hyper-reflexia of the H-reflex after spinal cord injury.

  17. Failure During Sheared Edge Stretching

    Science.gov (United States)

    Levy, B. S.; van Tyne, C. J.

    2008-12-01

    Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.

  18. Monosynaptic convergence of somatic and visceral C-fiber afferents on projection and local circuit neurons in lamina I: a substrate for referred pain.

    Science.gov (United States)

    Luz, Liliana L; Fernandes, Elisabete C; Sivado, Miklos; Kokai, Eva; Szucs, Peter; Safronov, Boris V

    2015-10-01

    Referred pain is a phenomenon of feeling pain at a site other than the site of the painful stimulus origin. It arises from a pathological mixing of nociceptive processing pathways for visceral and somatic inputs. Despite numerous studies based on unit recordings from spinal and supraspinal neurons, the exact mechanism and site of this mixing within the central nervous system are not known. Here, we selectively recorded from lamina I neurons, using a visually guided patch-clamp technique, in thoracic spinal cord preparation with preserved intercostal (somatic) and splanchnic (visceral) nerves. We show that somatic and visceral C fibers converge monosynaptically onto a group of lamina I neurons, which includes both projection and local circuit neurons. Other groups of lamina I neurons received inputs from either somatic or visceral afferents. We have also identified a population of lamina I local circuit neurons showing overall inhibitory responses upon stimulation of both nerves. Thus, the present data allow us to draw two major conclusions. First, lamina I of the spinal cord is the first site in the central nervous system where somatic and visceral pathways directly converge onto individual projection and local circuit neurons. Second, the mechanism of somatovisceral convergence is complex and based on functional integration of monosynaptic and polysynaptic excitatory as well as inhibitory inputs in specific groups of neurons. This complex pattern of convergence provides a substrate for alterations in the balance between visceral and somatic inputs causing referred pain.

  19. Provocation of aspiration reflexes and their effects on the pattern of cough and reflex apnea in cats.

    Science.gov (United States)

    Poliacek, I; Tomori, Z; Simera, M; Barani, H; Visnovcova, N; Halasova, E; Donic, V; Jakus, J

    2009-11-01

    Aspiration reflexes (AspRs) manifesting as reflex spasmodic inspirations and their effects on motor pattern of tracheobronchial cough and reflex apnea were studied on 22 spontaneously breathing pentobarbitone-anesthetized cats. AspRs induced during cough inspiration enhanced peak inspiratory (P<0.01) and expiratory (P<0.02) esophageal pressures, amplitudes of diaphragm (P<0.01) and abdominal muscles (P<0.05) EMG activity, and prolonged the entire expiratory period (P<0.01) and total cycle duration (P<0.05) of cough. Transient inhibitions and splits of cough expiration frequently occurred with AspR within active cough expiratory period; however, cough spatiotemporal characteristics were not altered significantly. Sub-threshold nasopharyngeal stimulation failing to provoke AspR had no significant effects on coughing. Hering-Breuer inflation apnea was moderately prolonged by AspRs (20%; P<0.05), unlike the apnea produced by continual mechanical laryngeal stimulation. AspRs are inducible during tested behaviors interacting with their motor pattern. Central mechanisms involving pulmonary stretch receptor stimulation is suggested for modulation of cough and inflation apnea by AspR.

  20. A patient with reflex myoclonus and muscle rigidity: "jerking stiff-man syndrome".

    OpenAIRE

    Leigh, P N; J. C. Rothwell; Traub, M.; Marsden, C. D.

    1980-01-01

    A patient with progressive muscular rigidity associated with reflex myoclonus is described. The muscular rigidity was predominantly axial, and the myoclonic jerks affected axial and leg muscles. Jerks occurred either spontaneously, or in response to touch to the perioral region, or to stretch of head and neck muscles. Physiological investigations suggested that the myoclonus originated in the medulla and was mediated by fast-conducting pathways upwards through the brainstem and down the spina...

  1. Peripheral δ-opioid receptors attenuate the exercise pressor reflex.

    Science.gov (United States)

    Leal, Anna K; Yamauchi, Katsuya; Kim, Joyce; Ruiz-Velasco, Victor; Kaufman, Marc P

    2013-10-15

    In rats with ligated femoral arteries, the exercise pressor reflex is exaggerated, an effect that is attenuated by stimulation of peripheral μ-opioid receptors on group IV metabosensitive afferents. In contrast, δ-opioid receptors are expressed mostly on group III mechanosensitive afferents, a finding that prompted us to determine whether stimulation of these opioid receptors could also attenuate the exaggerated exercise pressor reflex in "ligated" rats. We found femoral arterial injection of [D-Pen2,D-Pen5]enkephalin (DPDPE; 1.0 μg), a δ-opioid agonist, significantly attenuated the pressor and cardioaccelerator components of the exercise pressor reflex evoked by hindlimb muscle contraction in both rats with ligated and patent femoral arteries. DPDPE significantly decreased the pressor responses to muscle mechanoreflex activation, evoked by tendon stretch, in ligated rats only. DPDPE (1.0 μg) had no effect in either group on the pressor and cardioaccelerator responses to capsaicin (0.2 μg), which primarily stimulates group IV afferents. DPDPE (1.0 μg) had no effect on the pressor and cardioaccelerator responses to lactic acid (24 mM), which stimulates group III and IV afferents, in rats with patent femoral arteries but significantly decreased the pressor response in ligated rats. Western blots revealed the amount of protein comprising the δ-opioid receptor was greater in dorsal root ganglia innervating hindlimbs with ligated femoral arteries than in dorsal root ganglia innervating hindlimbs with patent femoral arteries. Our findings support the hypothesis that stimulation of δ-opioid receptors on group III afferents attenuated the exercise pressor reflex.

  2. Outside home. Notes on reflexivity

    Directory of Open Access Journals (Sweden)

    Mara Clemente

    2017-01-01

    The paper proffers the idea in which a “reflexive process” on subjectivity can involve and/or hopefully involve the entire experience of the researcher, going beyond the borders of a single research. In the process, unexpected elements of subjectivity can come into play; in other cases the meaning attributed to them can change in time or can have a role different from what had been expected. Some elements, objects of epistemological analyses, as imposed by a reflexive approach, can become objects of attention also on the phenomenological level.

  3. Design of Warped Stretch Transform

    Science.gov (United States)

    Mahjoubfar, Ata; Chen, Claire Lifan; Jalali, Bahram

    2015-11-01

    Time stretch dispersive Fourier transform enables real-time spectroscopy at the repetition rate of million scans per second. High-speed real-time instruments ranging from analog-to-digital converters to cameras and single-shot rare-phenomena capture equipment with record performance have been empowered by it. Its warped stretch variant, realized with nonlinear group delay dispersion, offers variable-rate spectral domain sampling, as well as the ability to engineer the time-bandwidth product of the signal’s envelope to match that of the data acquisition systems. To be able to reconstruct the signal with low loss, the spectrotemporal distribution of the signal spectrum needs to be sparse. Here, for the first time, we show how to design the kernel of the transform and specifically, the nonlinear group delay profile dictated by the signal sparsity. Such a kernel leads to smart stretching with nonuniform spectral resolution, having direct utility in improvement of data acquisition rate, real-time data compression, and enhancement of ultrafast data capture accuracy. We also discuss the application of warped stretch transform in spectrotemporal analysis of continuous-time signals.

  4. A Purposeful Dynamic Stretching Routine

    Science.gov (United States)

    Leon, Craig; Oh, Hyun-Ju; Rana, Sharon

    2012-01-01

    Dynamic stretching, which involves moving parts of the body and gradually increases range of motion, speed of movement, or both through controlled, sport-specific movements, has become the popular choice of pre-exercise warm-up. This type of warm-up has evolved to encompass several variations, but at its core is the principle theme that preparing…

  5. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  6. Optical tweezers stretching of chromatin

    NARCIS (Netherlands)

    Pope, L.H.; Bennink, Martin L.; Greve, Jan

    2003-01-01

    Recently significant success has emerged from exciting research involving chromatin stretching using optical tweezers. These experiments, in which a single chromatin fibre is attached by one end to a micron-sized bead held in an optical trap and to a solid surface or second bead via the other end,

  7. Should Athletes Stretch before Exercise?

    Institute of Scientific and Technical Information of China (English)

    KarlB.Fields,MD; CraigM.Burnworth,MD; Martha Delaney·MA

    2007-01-01

    @@ KEY POINTS Traditional stretching routines performed during warm-up procedures before exercise can increase flexibility for a short time, but there is little scientific evidence that such routines can improve exercise performance, reduce delayed-onset muscular soreness, or prevent injuries.

  8. Iterated Stretching of Viscoelastic Jets

    Science.gov (United States)

    Chang, Hsueh-Chia; Demekhin, Evgeny A.; Kalaidin, Evgeny

    1999-01-01

    We examine, with asymptotic analysis and numerical simulation, the iterated stretching dynamics of FENE and Oldroyd-B jets of initial radius r(sub 0), shear viscosity nu, Weissenberg number We, retardation number S, and capillary number Ca. The usual Rayleigh instability stretches the local uniaxial extensional flow region near a minimum in jet radius into a primary filament of radius [Ca(1 - S)/ We](sup 1/2)r(sub 0) between two beads. The strain-rate within the filament remains constant while its radius (elastic stress) decreases (increases) exponentially in time with a long elastic relaxation time 3We(r(sup 2, sub 0)/nu). Instabilities convected from the bead relieve the tension at the necks during this slow elastic drainage and trigger a filament recoil. Secondary filaments then form at the necks from the resulting stretching. This iterated stretching is predicted to occur successively to generate high-generation filaments of radius r(sub n), (r(sub n)/r(sub 0)) = square root of 2[r(sub n-1)/r(sub 0)](sup 3/2) until finite-extensibility effects set in.

  9. A Purposeful Dynamic Stretching Routine

    Science.gov (United States)

    Leon, Craig; Oh, Hyun-Ju; Rana, Sharon

    2012-01-01

    Dynamic stretching, which involves moving parts of the body and gradually increases range of motion, speed of movement, or both through controlled, sport-specific movements, has become the popular choice of pre-exercise warm-up. This type of warm-up has evolved to encompass several variations, but at its core is the principle theme that preparing…

  10. Enhanced D1 and D2 inhibitions induced by low-frequency trains of conditioning stimuli: differential effects on H- and T-reflexes and possible mechanisms.

    Science.gov (United States)

    Mezzarane, Rinaldo André; Magalhães, Fernando Henrique; Chaud, Vitor Martins; Elias, Leonardo Abdala; Kohn, André Fabio

    2015-01-01

    Mechanically evoked reflexes have been postulated to be less sensitive to presynaptic inhibition (PSI) than the H-reflex. This has implications on investigations of spinal cord neurophysiology that are based on the T-reflex. Preceding studies have shown an enhanced effect of PSI on the H-reflex when a train of ~10 conditioning stimuli at 1 Hz was applied to the nerve of the antagonist muscle. The main questions to be addressed in the present study are if indeed T-reflexes are less sensitive to PSI and whether (and to what extent and by what possible mechanisms) the effect of low frequency conditioning, found previously for the H-reflex, can be reproduced on T-reflexes from the soleus muscle. We explored two different conditioning-to-test (C-T) intervals: 15 and 100 ms (corresponding to D1 and D2 inhibitions, respectively). Test stimuli consisted of either electrical pulses applied to the posterior tibial nerve to elicit H-reflexes or mechanical percussion to the Achilles tendon to elicit T-reflexes. The 1 Hz train of conditioning electrical stimuli delivered to the common peroneal nerve induced a stronger effect of PSI as compared to a single conditioning pulse, for both reflexes (T and H), regardless of C-T-intervals. Moreover, the conditioning train of pulses (with respect to a single conditioning pulse) was proportionally more effective for T-reflexes as compared to H-reflexes (irrespective of the C-T interval), which might be associated with the differential contingent of Ia afferents activated by mechanical and electrical test stimuli. A conceivable explanation for the enhanced PSI effect in response to a train of stimuli is the occurrence of homosynaptic depression at synapses on inhibitory interneurons interposed within the PSI pathway. The present results add to the discussion of the sensitivity of the stretch reflex pathway to PSI and its functional role.

  11. Educating the Reflexive Practitioner

    Directory of Open Access Journals (Sweden)

    Marc J. Neveu

    2012-09-01

    wearing any clothes.Notwithstanding such issues, I do believe the studio holds the potentialto be an empowering learning experience. The intention of this article is to question the mode of instruction in an architectural studio. I’ve structured the paper in three parts. First, I will briefly describe the findingsof the study made by the Carnegie Foundation for the Advancementof Teaching known as the Boyer Report.2 To develop and support the findings of the Boyer Report, I introduce the work of the educator Donald Schön. Though I see much merit in the Boyer Report, and Schön’sproposals, I argue that a more nuanced approach is required. I will recommend, therefore, in the second section of this paper that a meansof architectural education as based on the Socratic method may be amore productive approach. My reading of the Socratic method is basedprimarily on early Socratic dialogues and I will specifically use Charmidesto illustrate the issues that I believe are relevant to studio pedagogy.3 From my analysis of Charmides I will, in the third section of the essay,describe how the Socratic method is beneficial to studio pedagogy threeways: reflexive, non-propositional, and finally how Socrates’ approachmay indeed be practical. This last section will be illustrated with a studentproject. It is my conjecture that the Socratic method offers insight intocurrent discussions of educational theory, namely student-centered,project-based learning.

  12. The reflexive case study method

    DEFF Research Database (Denmark)

    Rittenhofer, Iris

    2015-01-01

    This paper extends the international business research on small to medium-sized enterprises (SME) at the nexus of globalization. Based on a conceptual synthesis across disciplines and theoretical perspectives, it offers management research a reflexive method for case study research of postnational...

  13. Does Acute Static Stretching Reduce Muscle Power?

    OpenAIRE

    Francis M. Kozub; Sameer A. Gohir; Alan Donnelly

    2012-01-01

    Context: Stretching is commonly used as a technique for injury prevention in the training and clinical setting. Recently, stretching in the warm-up has been shown to decrease several muscular performance variables, but the dose-response of this effect is unknown and moreover these stretching bouts are not representative of athletes during warm up procedures, as they are usually time consuming. Our findings may improve the understanding of the neuromuscular responses to stretching and help spo...

  14. Analysis of a filament stretching rheometer

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1996-01-01

    A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown.......A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown....

  15. Reassessment of Non-Monosynaptic Excitation from the Motor Cortex to Motoneurons in Single Motor Units of the Human Biceps Brachii.

    Science.gov (United States)

    Nakajima, Tsuyoshi; Tazoe, Toshiki; Sakamoto, Masanori; Endoh, Takashi; Shibuya, Satoshi; Elias, Leonardo A; Mezzarane, Rinaldo A; Komiyama, Tomoyoshi; Ohki, Yukari

    2017-01-01

    Corticospinal excitation is mediated by polysynaptic pathways in several vertebrates, including dexterous monkeys. However, indirect non-monosynaptic excitation has not been clearly observed following transcranial electrical stimulation (TES) or cervicomedullary stimulation (CMS) in humans. The present study evaluated indirect motor pathways in normal human subjects by recording the activities of single motor units (MUs) in the biceps brachii (BB) muscle. The pyramidal tract was stimulated with weak TES, CMS, and transcranial magnetic stimulation (TMS) contralateral to the recording side. During tasks involving weak co-contraction of the BB and hand muscles, all stimulation methods activated MUs with short latencies. Peristimulus time histograms (PSTHs) showed that responses with similar durations were induced by TES (1.9 ± 1.4 ms) and CMS (2.0 ± 1.4 ms), and these responses often showed multiple peaks with the PSTH peak having a long duration (65.3% and 44.9%, respectively). Such long-duration excitatory responses with multiple peaks were rarely observed in the finger muscles following TES or in the BB following stimulation of the Ia fibers. The responses obtained with TES were compared in the same 14 BB MUs during the co-contraction and isolated BB contraction tasks. Eleven and three units, respectively, exhibited activation with multiple peaks during the two tasks. In order to determine the dispersion effects on the axon conduction velocities (CVs) and synaptic noise, a simulation study that was comparable to the TES experiments was performed with a biologically plausible neuromuscular model. When the model included the monosynaptic-pyramidal tract, multiple peaks were obtained in about 34.5% of the motoneurons (MNs). The experimental and simulation results indicated the existence of task-dependent disparate inputs from the pyramidal tract to the MNs of the upper limb. These results suggested that intercalated interneurons are present in the spinal cord and

  16. Reassessment of Non-Monosynaptic Excitation from the Motor Cortex to Motoneurons in Single Motor Units of the Human Biceps Brachii

    Science.gov (United States)

    Nakajima, Tsuyoshi; Tazoe, Toshiki; Sakamoto, Masanori; Endoh, Takashi; Shibuya, Satoshi; Elias, Leonardo A.; Mezzarane, Rinaldo A.; Komiyama, Tomoyoshi; Ohki, Yukari

    2017-01-01

    Corticospinal excitation is mediated by polysynaptic pathways in several vertebrates, including dexterous monkeys. However, indirect non-monosynaptic excitation has not been clearly observed following transcranial electrical stimulation (TES) or cervicomedullary stimulation (CMS) in humans. The present study evaluated indirect motor pathways in normal human subjects by recording the activities of single motor units (MUs) in the biceps brachii (BB) muscle. The pyramidal tract was stimulated with weak TES, CMS, and transcranial magnetic stimulation (TMS) contralateral to the recording side. During tasks involving weak co-contraction of the BB and hand muscles, all stimulation methods activated MUs with short latencies. Peristimulus time histograms (PSTHs) showed that responses with similar durations were induced by TES (1.9 ± 1.4 ms) and CMS (2.0 ± 1.4 ms), and these responses often showed multiple peaks with the PSTH peak having a long duration (65.3% and 44.9%, respectively). Such long-duration excitatory responses with multiple peaks were rarely observed in the finger muscles following TES or in the BB following stimulation of the Ia fibers. The responses obtained with TES were compared in the same 14 BB MUs during the co-contraction and isolated BB contraction tasks. Eleven and three units, respectively, exhibited activation with multiple peaks during the two tasks. In order to determine the dispersion effects on the axon conduction velocities (CVs) and synaptic noise, a simulation study that was comparable to the TES experiments was performed with a biologically plausible neuromuscular model. When the model included the monosynaptic-pyramidal tract, multiple peaks were obtained in about 34.5% of the motoneurons (MNs). The experimental and simulation results indicated the existence of task-dependent disparate inputs from the pyramidal tract to the MNs of the upper limb. These results suggested that intercalated interneurons are present in the spinal cord and

  17. Polymer network stretching during electrospinning

    Science.gov (United States)

    Greenfeld, Israel; Arinstein, Arkadii; Fezzaa, Kamel; Rafailovich, Miriam; Zussman, Eyal

    2011-03-01

    Fast X-ray phase contrast imaging is used to observe the flow of a semi-dilute polyethylene oxide solution during electrospinning. Micron-size glass particles mixed in the polymer solution allow viewing of the jet flow field, and reveal a high-gradient flow that has both longitudinal and radial components that grow rapidly along the jet. The resulting hydrodynamic forces cause substantial longitudinal stretching and transversal contraction of the polymer network within the jet, as confirmed by random walk simulation and theoretical modeling. The polymer network therefore concentrates towards the jet center, and its conformation may transform from a free state to a fully-stretched state within a short distance from the jet start. We acknowledge the financial support of the United States - Israel Bi-National Science Foundation (grant 2006061).

  18. F response and H reflex analysis of physiological unity of gravity and antigravity muscles in man.

    Science.gov (United States)

    García, H A; Fisher, M A

    1977-01-01

    Observational differences between reflex (H reflex) and antidromic (F response) activation of segmental motoneurons by a peripheral electrical stimulus are described. In contrast to H reflexes, the percentage of F responses found after a series of stimuli is directly related to the pick-up field of the recording electrode consistent with this response being due to the variable activation of a small fraction of the available motoneuron pool. Despite the differing physiological mechanisms, both F responses and H reflexes can be used to demonstrate similar relative "central excitatory states" for antigravity muscles (i.e. extensors in the lower extremity and flexors in the upper extremity) and their antagonist gravity muscles. H reflexes were elicited not only in their usual location in certain antigravity muscles but also in unusual locations by length/tension changes in agonist and antagonist groups as well as by passive stretch. The data argue for the physiological unity of similarly acting gravity and antigravity muscles as well as supporting a meaningful role of group II afferents in normal segmental motoneuron pool excitability.

  19. Prophylactic stretching does not reduce cramp susceptibility.

    Science.gov (United States)

    Miller, Kevin C; Harsen, James D; Long, Blaine C

    2017-08-10

    Some clinicians advocate stretching to prevent muscle cramps. It is unknown whether static or proprioceptive neuromuscular facilitation (PNF) stretching increases cramp threshold frequency (TFc ), a quantitative measure of cramp susceptibility. Fifteen individuals completed this randomized, counterbalanced, cross-over study. We measured passive hallux range of motion (ROM) and then performed 3 minutes of either static stretching, PNF stretching (hold-relax-with agonist contraction), or no stretching. ROM was reassessed and TFc was measured. PNF stretching increased hallux extension (pre-PNF 81 ± 11°, post-PNF 90 ± 10°; P 0.05). Static stretching increased hallux extension (pre-static 80 ± 11°, post-static 88 ± 9°; P 0.05). No ROM changes occurred with no stretching (P > 0.05). TFc was unaffected by stretching (no stretching 18 ± 7 Hz, PNF 16 ± 4 Hz, static 16 ± 5 Hz; P = 0.37). Static and PNF stretching increased hallux extension, but neither increased TFc . Acute stretching may not prevent muscle cramping. Muscle Nerve, 2017. © 2017 Wiley Periodicals, Inc.

  20. Modified "DMC" technique for stretching DNA molecules

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A modified "dynamic molecular combing"(DMC)technique used for stretching double-strandedDNA is reported. DNA molecules were stretched on the silanized mica surface by thistechnique, its speed being precisely controlled with a computer. This approachcombinedthe precise DNA stretching method with high resolution AFM imaging at nanometer scale,thusmaking it useful for DNA alignment manipulation and subsequent gene research.

  1. Local stretch zeroing NMO correction

    Science.gov (United States)

    Kazemi, N.; Siahkoohi, H. R.

    2012-01-01

    In this paper we present a new method of normal move-out (NMO) correction called local stretch zeroing (LSZ) method that avoids NMO stretch. The method eliminates the theoretical curves that generate interpolated data samples responsible for NMO stretch. Pre-correction time sampling interval is preserved by reassigning and zero padding of true data samples. The optimum mute zone selection feature of the LSZ method eliminates all interfering reflection events at far offsets. The resulted stacked section from the LSZ method contains generally higher frequency components than a normal stack, and preserves most of the shallow reflectors. The LSZ method requires that zero-offset width of the time gate, i.e. zero-offset time difference between two adjacent reflections, be larger than the dominant period. The major shortcoming of the method occurs when CMP data are over- or under-NMO corrected. Both synthetic and real world examples show the efficiency of the LSZ method over the conventional NMO (CNMO) correction. The method loses its superiority when CMP data are over- or under-NMO corrected.

  2. Inhibition of nitric oxide synthesis accelerates the recovery of polysynaptic reflex potentials after transient spinal cord ischemia in cats.

    Science.gov (United States)

    Nemoto, T; Sekikawa, T; Suzuki, T; Moriya, H; Nakaya, H

    1997-04-01

    Nitric Oxide (NO) has been implicated as a mediator of neuronal injury in vascular stroke. On the other hand, NO is suggested to play a neuroprotective role by increasing blood flow during cerebral ischemia. In order to evaluate the role of NO in the spinal cord ischemia, effects of nitric oxide synthase (NOS) inhibition on the recovery of reflex potentials after a transient spinal cord ischemia were examined in urethane-chloralose anesthetized spinal cats. Spinal cord ischemia was produced by occlusion of the thoracic aorta and the both internal mammary arteries for 10 min. Regional blood flow (RBF) in the spinal cord was continuously measured with a laser-Doppler flow meter. The monosynaptic (MSR) and polysynaptic reflex (PSR) potentials elicited by electrical stimulation of the tibial nerve, were recorded from the L7 or S1 ventral root. The recovery process of spinal reflex potentials was reproducible when the oclusion was repeated twice at an interval of 120 min. Pretreatment with N(G)-monomethyl-L-arginine (L-NMMA, 10 mg/kg), a NOS inhibitor significantly accelerated the recovery of PSR potentials after spinal cord ischemia. The accelerating effect of L-NMMA on the recovery of PSR potentials was abolished by co-administration of L-arginine (1 mg/kg/min) but not by that of D-arginine (1 mg/kg/min). L-NMMA failed to improve RBF in the spinal cord during ischemia and reperfusion. Nitroprusside (10 microg/kg/min), a NO donor, retarded the recovery of PSR potentials after spinal cord ischemia. These results suggest that NO production has a significant influence on the functional recovery after transient spinal cord ischemia.

  3. Effects of static stretching for 30 seconds and dynamic stretching on leg extension power.

    Science.gov (United States)

    Yamaguchi, Taichi; Ishii, Kojiro

    2005-08-01

    The purposes of this study were to clarify the effects of static stretching for 30 seconds and dynamic stretching on leg extension power. Eleven healthy male students took part in this study. Each subject performed static stretching and dynamic stretching on the 5 muscle groups in the lower limbs and nonstretching on separate days. Leg extension power was measured before and after the static stretching, dynamic stretching, and nonstretching. No significant difference was found between leg extension power after static stretching (1788.5 +/- 85.7 W) and that after nonstretching (1784.8 +/- 108.4 W). On the other hand, leg extension power after dynamic stretching (2022.3 +/- 121.0 W) was significantly (p < 0.01) greater than that after nonstretching. These results suggest that static stretching for 30 seconds neither improves nor reduces muscular performance and that dynamic stretching enhances muscular performance.

  4. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    Ľ Ambriško; L Pešek

    2014-04-01

    The paper deals with an experimental determination of the stretch zone dimensions in the notch tip in thin steel sheets. The stretch zone dimensions depend on steel grade, on the rolling direction as well as on the loading rate. Stretch zones were observed and measured on three steel grades. Fracture area and stretch zones were analysed by SEM. Stable crack growth was monitored by videoextensometry techniques on CT (Compact Tension) specimens. Specimens were loaded under two loading rates by eccentric tension, whereby the deformation in the notch surrounding area was recorded using a non-contact measurement–videoextensometry technique. Linear relation between the stretch zone dimensions was determined.

  5. Reflexivity in Narratives on Practice

    DEFF Research Database (Denmark)

    Jakobsen, Helle Nordentoft; Olesen, Lektor Birgitte Ravn

    Previous research has shown how reflexivity is a precondition for knowledge co-production through productive dialogue in organisational contexts because it entails a re-ordering, re-arranging and re-designing of what one knows and therefore creates new angles of vision. In this paper, we draw...... on Bakhtinian dialogic communication theory and discursive psychology to investigate the written practice narratives of 23 students on a Masters Degree Programme in Educational Studies, focusing on how the process of writing narratives accentuates reflexivity. Our findings indicate that the narratives invite...... a dialogic conception of practice as they entail a conceptual reframing of key elements in practice. In addition, the narratives expose a situational and relational, rather than normative, focus which allows for reflections on emotional and bodily experiences. In conclusion, we argue that practice narratives...

  6. Integrating Reflexivity in Livelihoods Research

    DEFF Research Database (Denmark)

    Prowse, Martin

    2010-01-01

    Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods researc...... that overcomes the unproductive social science dualism of positivism and social constructivism. The approach is linked to a conceptual framework and a menu of research methods that can be sequenced and iterated in light of research questions.......Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods research...

  7. Reflexive fatherhood in everyday life

    DEFF Research Database (Denmark)

    Westerling, Allan

    2015-01-01

    This article looks at fathering practices in Denmark, using the findings from a research project on everyday family life in Denmark. It takes a social psychological perspective and employs discursive psychology and theories about reflexive modernisation. It shows how fathers orient towards intimacy...... this analysis and discussion, the article offers a way to understand the complexities of fathering in everyday life from the perspective of fathers....

  8. Integrating Reflexivity in Livelihoods Research

    DEFF Research Database (Denmark)

    Prowse, Martin

    2010-01-01

    Much poverty and development research is not explicit about its methodology or philosophical foundations. Based on the extended case method of Burawoy and the epistemological standpoint of critical realism, this paper discusses a methodological approach for reflexive inductive livelihoods researc...... that overcomes the unproductive social science dualism of positivism and social constructivism. The approach is linked to a conceptual framework and a menu of research methods that can be sequenced and iterated in light of research questions....

  9. Butterflies on the Stretched Horizon

    CERN Document Server

    Susskind, Leonard

    2013-01-01

    In this paper I return to the question of what kind of perturbations on Alice's side of an Einstein-Rosen bridge can send messages to Bob as he enters the horizon at the other end. By definition "easy" operators do not activate messages and "hard" operators do, but there are no clear criteria to identify the difference between easy and hard. In this paper I argue that the difference is related to the time evolution of a certain measure of computational complexity, associated with the stretched horizon of Alice's black hole. The arguments suggest that the AMPSS commutator argument is more connected with butterflies than with firewalls.

  10. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  11. Laser therapy of stretch marks.

    Science.gov (United States)

    McDaniel, David H

    2002-01-01

    Striae distensae, better known as stretch marks, are a common disfiguring skin disorder of significant cosmetic concern. Many sources have reported the use of lasers to diminish the appearance of striae. Controlled clinical studies of the various treatment modalities available for striae are relatively uncommon, and much of the clinical data are anecdotal. The use of lasers alone or in combination with other therapeutic modalities can provide a safe and effective reduction in the appearance of both red and white striae distensae. Many of these therapies require special measures for darker skin phototypes. This article reviews the historical use of laser therapy for this disorder and discusses current therapeutic options.

  12. Voluntary reaction time and long-latency reflex modulation.

    Science.gov (United States)

    Forgaard, Christopher J; Franks, Ian M; Maslovat, Dana; Chin, Laurence; Chua, Romeo

    2015-12-01

    Stretching a muscle of the upper limb elicits short (M1) and long-latency (M2) reflexes. When the participant is instructed to actively compensate for a perturbation, M1 is usually unaffected and M2 increases in size and is followed by the voluntary response. It remains unclear if the observed increase in M2 is due to instruction-dependent gain modulation of the contributing reflex mechanism(s) or results from voluntary response superposition. The difficulty in delineating between these alternatives is due to the overlap between the voluntary response and the end of M2. The present study manipulated response accuracy and complexity to delay onset of the voluntary response and observed the corresponding influence on electromyographic activity during the M2 period. In all active conditions, M2 was larger compared with a passive condition where participants did not respond to the perturbation; moreover, these changes in M2 began early in the appearance of the response (∼ 50 ms), too early to be accounted for by voluntary overlap. Voluntary response latency influenced the latter portion of M2, with the largest activity seen when accuracy of limb position was not specified. However, when participants aimed for targets of different sizes or performed movements of various complexities, reaction time differences did not influence M2 period activity, suggesting voluntary activity was sufficiently delayed. Collectively, our results show that while a perturbation applied to the upper limbs can trigger a voluntary response at short latency (reflex gain modulation remains an important contributor to EMG changes during the M2 period. Copyright © 2015 the American Physiological Society.

  13. Evidence for a supraspinal contribution to the human quadriceps long-latency stretch reflex

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, N.; Grey, Michael James; Sinkjær, Thomas

    2006-01-01

    ). The aim of this study was to determine if a transcortical pathway contributes to any of these bursts. Flexion perturbations (amplitude =4 degrees, velocity=150 degrees/s) were imposed on the right knee joint of sitting subjects (n=11). The effect of the perturbation on the electromyographic (EMG) response...

  14. [Clinical relevance of cardiopulmonary reflexes in anesthesiology].

    Science.gov (United States)

    Guerri-Guttenberg, R A; Siaba-Serrate, F; Cacheiro, F J

    2013-10-01

    The baroreflex, chemoreflex, pulmonary reflexes, Bezold-Jarisch and Bainbridge reflexes and their interaction with local mechanisms, are a demonstration of the richness of cardiovascular responses that occur in human beings. As well as these, the anesthesiologist must contend with other variables that interact by attenuating or accentuating cardiopulmonary reflexes such as, anesthetic drugs, surgical manipulation, and patient positioning. In the present article we review these reflexes and their clinical relevance in anesthesiology. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

  15. Neural reflexes in inflammation and immunity

    National Research Council Canada - National Science Library

    Andersson, Ulf; Tracey, Kevin J

    2012-01-01

    .... Development of advanced neurophysiological and immunological techniques recently enabled the study of reflex neural circuits that maintain immunological homeostasis, and are essential for health in mammals...

  16. Reflexive Aero Structures for Enhanced Survivability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) will develop an advanced reflexive structure technology system to increase the survivability of future systems constructed of...

  17. Fluid Stretching as a Levy Process

    CERN Document Server

    Dentz, Marco; Borgne, Tanguy Le; de Barros, Felipe P J

    2016-01-01

    We uncover deformation dynamics that lead to power-law stretching of material lines in heterogeneous flow. This evidences the existence of a broad spectrum of algebraic stretching behaviors in fluids from sub- to superlinear beyond the linear (shear flow) and exponential (chaotic flow) elongation paradigms. Formulating fluid deformation in two-dimensional steady flow in stream-line coordinates, we show that stretching results from the non-linear coupling between Lagrangian shear deformation and velocity fluctuations. Casting the stretching process in the frame of a continuous time random walk, this coupling links the magnitude of elongation events to their persistence through the transit times of material strips. As a consequence, for broad transit time distributions stretching obeys Levy dynamics. We derive explicit expressions for the mean elongation which predict a broad range of power-law stretching behaviors depending on the velocity distribution and the relation between shear rate and velocity along str...

  18. Priming Neural Circuits to Modulate Spinal Reflex Excitability

    Science.gov (United States)

    Estes, Stephen P.; Iddings, Jennifer A.; Field-Fote, Edelle C.

    2017-01-01

    While priming is most often thought of as a strategy for modulating neural excitability to facilitate voluntary motor control, priming stimulation can also be utilized to target spinal reflex excitability. In this application, priming can be used to modulate the involuntary motor output that often follows central nervous system injury. Individuals with spinal cord injury (SCI) often experience spasticity, for which antispasmodic medications are the most common treatment. Physical therapeutic/electroceutic interventions offer an alternative treatment for spasticity, without the deleterious side effects that can accompany pharmacological interventions. While studies of physical therapeutic/electroceutic interventions have been published, a systematic comparison of these approaches has not been performed. The purpose of this study was to compare four non-pharmacological interventions to a sham-control intervention to assess their efficacy for spasticity reduction. Participants were individuals (n = 10) with chronic SCI (≥1 year) who exhibited stretch-induced quadriceps spasticity. Spasticity was quantified using the pendulum test before and at two time points after (immediate, 45 min delayed) each of four different physical therapeutic/electroceutic interventions, plus a sham-control intervention. Interventions included stretching, cyclic passive movement (CPM), transcutaneous spinal cord stimulation (tcSCS), and transcranial direct current stimulation (tDCS). The sham-control intervention consisted of a brief ramp-up and ramp-down of knee and ankle stimulation while reclined with legs extended. The order of interventions was randomized, and each was tested on a separate day with at least 48 h between sessions. Compared to the sham-control intervention, stretching, CPM, and tcSCS were associated with a significantly greater reduction in spasticity immediately after treatment. While the immediate effect was largest for stretching, the reduction persisted

  19. Reflexivity in Narratives on Practice

    DEFF Research Database (Denmark)

    Jakobsen, Helle Nordentoft; Olesen, Lektor Birgitte Ravn

    on Bakhtinian dialogic communication theory and discursive psychology to investigate the written practice narratives of 23 students on a Masters Degree Programme in Educational Studies, focusing on how the process of writing narratives accentuates reflexivity. Our findings indicate that the narratives invite...... a dialogic conception of practice as they entail a conceptual reframing of key elements in practice. In addition, the narratives expose a situational and relational, rather than normative, focus which allows for reflections on emotional and bodily experiences. In conclusion, we argue that practice narratives...

  20. Two ways to support reflexivity

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine; Knudsen, Hanne

    2013-01-01

    Management (MEM). MEM provides the participating managers with a new language that can give them a critical distance to the overload of expectations they meet at work and MEM teaches the participants to translate this new language into practice. The pedagogy used for this is labelled ‘experimental management......’. This requires participants to conduct experiments in their own organization, to reflect on and analyse their experiences with concepts from the curriculum. While the new language and the experimental teaching format are difficult, the participants learn a reflexive practice that can enable them to life up...

  1. Structural cure for reflex syncope?

    Science.gov (United States)

    Sulke, Neil; Eysenck, William; Badiani, Sveeta; Furniss, Stephen

    2016-01-20

    The ROX Coupler is a device that allows creation of a central arteriovenous anastomosis at the iliac level. The device has been shown to improve exercise capacity in patients with chronic obstructive pulmonary disease and is CE marked for the treatment of resistant and uncontrolled hypertension. Reflex syncope is a challenging clinical condition with limited proven therapeutic options. We describe the resolution of symptoms and tilt table response of a patient who underwent insertion of a ROX Coupler to treat hypertension, and also incidentally had pre-existing vasodepressor syncope.

  2. The Dynamics of the Stapedial Acoustic Reflex.

    Science.gov (United States)

    Moss, Sherrin Mary

    Available from UMI in association with The British Library. This thesis aims to separate the neural and muscular components of the stapedial acoustic reflex, both anatomically and physiologically. It aims to present an hypothesis to account for the differences between ipsilateral and contralateral reflex characteristics which have so far been unexplained, and achieve a greater understanding of the mechanisms underlying the reflex dynamics. A technique enabling faithful reproduction of the time course of the reflex is used throughout the experimental work. The technique measures tympanic membrane displacement as a result of reflex stapedius muscle contraction. The recorded response can be directly related to the mechanics of the middle ear and stapedius muscle contraction. Some development of the technique is undertaken by the author. A model of the reflex neural arc and stapedius muscle dynamics is evolved that is based upon a second order system. The model is unique in that it includes a latency in the ipsilateral negative feedback loop. Oscillations commonly observed on reflex responses are seen to be produced because of the inclusion of a latency in the feedback loop. The model demonstrates and explains the complex relationships between neural and muscle dynamic parameters observed in the experimental work. This more comprehensive understanding of the interaction between the stapedius dynamics and the neural arc of the reflex would not usually have been possible using human subjects, coupled with a non-invasive measurement technique. Evidence from the experimental work revealed the ipsilateral reflex to have, on average, a 5 dB lower threshold than the contralateral reflex. The oscillatory charcteristics, and the steady state response, of the contralateral reflex are also seen to be significantly different from those of the ipsilateral reflex. An hypothesis to account for the experimental observations is proposed. It is propounded that chemical neurotransmitters

  3. Stretching Folding Instability and Nanoemulsions

    CERN Document Server

    Chan, Chon U

    2009-01-01

    Here we show a folding-stretching instability in a microfluidic flow focusing device using silicon oil (100cSt) and water. The fluid dynamics video demonstrates an oscillating thread of oil focused by two co-flowing streams of water. We show several high-speed sequences of these oscillations with 30,000 frames/s. Once the thread is decelerated in a slower moving pool downstream an instability sets in and water-in-oil droplets are formed. We reveal the details of the pinch-off with 500,000 frames/s. The pinch-off is so repeatable that complex droplet patterns emerge. Some of droplets are below the resolution limit, thus smaller than 1 micrometer in diameter.

  4. Cell reorientation under cyclic stretching

    CERN Document Server

    Livne, Ariel; Geiger, Benjamin

    2014-01-01

    Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations -- cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell's passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells, measu...

  5. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    Science.gov (United States)

    Bar-On, Lynn; Aertbeliën, Erwin; Molenaers, Guy; Desloovere, Kaat

    2014-01-01

    The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP) these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV) of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG) from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG) compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (pmuscles into activation patterns (pmuscles with different patterns react differently to treatment.

  6. [Non-reflex activity of the CNS].

    Science.gov (United States)

    Brozek, G

    1995-06-01

    Recent studies of biological rhythms have modified Sherrington's concept of nervous system as exclusively reflexive to include the fact that some neural activity is also endogenously rhythmic. Reflexes are undoubtedly the most important components of animal's and human behavior. But are reflexes the basic units of all complex movements and acts? Rhythmical movements such as respiration, walking and running and other forms of locomotion, as well as rhythmical alimentary processes such as respiration, walking and running and other forms of locomotion, as well as rhythmical alimentary processes such as licking, mastication, and the peristaltic propulsion of nutrients and waste are examples of acts controlled by intrinsic oscillators, so called central pattern generators. Information from the periphery is, however, essential for controlling the extent and rate of movements. Between reflex and non-reflex activity it is possible to place complex species-specific responses called by ethologists fixed-action patterns. Recent investigators have shown that many complex sequences of behavior like speech or piano playing are determined by an internal plan, rather than being generated by a "chain" of reflexes. Non-reflexive activity appears earlier in ontogeny, and is probably phylogenetically older than reflexes.

  7. Reflexive choice in Dutch and German

    NARCIS (Netherlands)

    Hendriks, Petra; Hoeks, John C. J.; Spenader, Jennifer

    2014-01-01

    Standard Dutch and German have two reflexive forms: a weak form ('zich' in Dutch and 'sich' in German) and a strong form ('zichzelf' in Dutch and 'sich selbst' in German). The choice between the two reflexive forms in Dutch has been explained by the selectional restrictions of the verb, distinguishi

  8. Reflexivity in Teams: A Measure and Correlates

    NARCIS (Netherlands)

    M.C. Schippers (Michaéla); D.N. den Hartog (Deanne); P.L. Koopman (Paul)

    2005-01-01

    textabstractReflexivity -the extent to which teams reflect upon and modify their functioning- has been identified as a possible key factor in the effectiveness of work teams. The aim of the present study was to develop a questionnaire to measure (aspects of) reflexivity, with a focus on team reflect

  9. Axon reflexes in human cold exposed fingers

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ducharme, M.B.

    2000-01-01

    Exposure of fingers to severe cold induces cold induced vasodilation (CIVD). The mechanism of CIVD is still debated. The original theory states that an axon reflex causes CIVD. To test this hypothesis, axon reflexes were evoked by electrical stimulation of the middle fingers of hands immersed in

  10. Axon reflexes in human cold exposed fingers

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ducharme, M.B.

    2000-01-01

    Exposure of fingers to severe cold induces cold induced vasodilation (CIVD). The mechanism of CIVD is still debated. The original theory states that an axon reflex causes CIVD. To test this hypothesis, axon reflexes were evoked by electrical stimulation of the middle fingers of hands immersed in wat

  11. [Cutaneo-muscular reflexes of the human hand. II. Neurophysiologic aspects of reflex organization and coordination].

    Science.gov (United States)

    Meinck, H M; Berkefeld, J; Conrad, B

    1987-09-01

    The organization and coordination of cutaneo-muscular reflexes of human finger and arm muscles to electrical stimulation of the digital nerves were investigated in 14 healthy volunteers. Thumb and finger muscles, although antagonists, showed homonymous reflex effects whereas the wrist and elbow muscles exhibited an reciprocally alternating reflex pattern in pairs of antagonists (Fig. 1). The mechanographical correlate of the homonymous reflex activity in distal muscles was a short release (Fig. 6). The receptive field for evoking such reflex effects covered both the palmar and dorsal surfaces of the fingers (Fig. 2). However, with stimulation of the thumb, the muscles of the fingers and of the wrist showed reflex reversal (Figs 3, 5). If the stimulus was moved from the second to the fifth fingers, a successive attenuation of the transcortical reflex component was seen (Fig. 4). It is concluded that the reflexes investigated are complex flexor reflexes comprising both a distal release and a proximal flexion synergy. According to opposition of the thumb in grasping, the receptive field terminates between thumb and index finger. These reflexes are supposed to have no assisting function during corticalized manipulatory movements--in contrast to the long-loop reflexes evoked by epicritic sensibility. The transcortical servo is blocked if the eliciting stimulus is contaminated by nociceptive signals; its receptive field is confined to those fingers used in the precision grip.

  12. Reliability of the NINDS Myotatic Reflex Scale.

    Science.gov (United States)

    Litvan, I; Mangone, C A; Werden, W; Bueri, J A; Estol, C J; Garcea, D O; Rey, R C; Sica, R E; Hallett, M; Bartko, J J

    1996-10-01

    The assessment of deep tendon reflexes is useful for localization and diagnosis of neurologic disorders, but only a few studies have evaluated their reliability. We assessed the reliability of four neurologists, instructed in two different countries, in using the National Institute of Neurological Disorders and Stroke (NINDS) Myotatic Reflex Scale. To evaluate the role of training in using the scale, the neurologists randomly and blindly evaluated a total of 80 patients, 40 before and 40 after a training session. Inter- and intraobserver reliability were measured with kappa statistics. Our results showed substantial to near-perfect intraobserver reliability, and moderate-to-substantial interobserver reliability of the NINDS Myotatic Reflex Scale. The reproducibility was better for reflexes in the lower than in the upper extremities. Neither educational background nor the training session influenced the reliability of our results. The NINDS Myotatic Reflex Scale has sufficient reliability to be adopted as a universal scale.

  13. Stretching Impacts Inflammation Resolution in Connective Tissue.

    Science.gov (United States)

    Berrueta, Lisbeth; Muskaj, Igla; Olenich, Sara; Butler, Taylor; Badger, Gary J; Colas, Romain A; Spite, Matthew; Serhan, Charles N; Langevin, Helene M

    2016-07-01

    Acute inflammation is accompanied from its outset by the release of specialized pro-resolving mediators (SPMs), including resolvins, that orchestrate the resolution of local inflammation. We showed earlier that, in rats with subcutaneous inflammation of the back induced by carrageenan, stretching for 10 min twice daily reduced inflammation and improved pain, 2 weeks after carrageenan injection. In this study, we hypothesized that stretching of connective tissue activates local pro-resolving mechanisms within the tissue in the acute phase of inflammation. In rats injected with carrageenan and randomized to stretch versus no stretch for 48 h, stretching reduced inflammatory lesion thickness and neutrophil count, and increased resolvin (RvD1) concentrations within lesions. Furthermore, subcutaneous resolvin injection mimicked the effect of stretching. In ex vivo experiments, stretching of connective tissue reduced the migration of neutrophils and increased tissue RvD1 concentration. These results demonstrate a direct mechanical impact of stretching on inflammation-regulation mechanisms within connective tissue.

  14. Anharmonic Bend-Stretch Coupling in Water

    NARCIS (Netherlands)

    Lindner, Jörg; Vöhringer, Peter; Pshenichnikov, Maxim S.; Cringus, Dan; Wiersma, Douwe A.; Corkum, Paul; Jonas, David M.; Miller, R.J. Dwayne.; Weiner, Andrew M.

    2006-01-01

    Following excitation of the H-O-H bending mode of water molecules in solution the stretching mode region is monitored over its entire width. The anharmonic coupling between the two modes results in a substantial change of the transient stretch absorption that decays with the bend depopulation time.

  15. STRETCHING IMPACTS INFLAMMATION RESOLUTION IN CONNECTIVE TISSUE

    Science.gov (United States)

    Berrueta, Lisbeth; Muskaj, Igla; Olenich, Sara; Butler, Taylor; Badger, Gary J.; Colas, Romain A.; Spite, Matthew; Serhan, Charles N.; Langevin, Helene M.

    2016-01-01

    Acute inflammation is accompanied from its outset by the release of specialized pro-resolving mediators (SPMs), including resolvins, that orchestrate the resolution of local inflammation. We showed earlier that, in rats with subcutaneous inflammation of the back induced by carrageenan, stretching for 10 minutes twice daily reduced inflammation and improved pain, two weeks after carrageenan injection. In this study, we hypothesized that stretching of connective tissue activates local pro-resolving mechanisms within the tissue in the acute phase of inflammation. In rats injected with carrageenan and randomized to stretch vs. no stretch for 48 hours, stretching reduced inflammatory lesion thickness and neutrophil count, and increased resolvin (RvD1) concentrations within lesions. Furthermore, subcutaneous resolvin injection mimicked the effect of stretching. In ex vivo experiments, stretching of connective tissue reduced the migration of neutrophils and increased tissue RvD1 concentration. These results demonstrate a direct mechanical impact of stretching on inflammation-regulation mechanisms within connective tissue. PMID:26588184

  16. A systematic muscle model covering regions from the fast ramp stretches in the muscle fibres to the relatively slow stretches in the human triceps surae.

    Science.gov (United States)

    Tamura, Youjiro; Ito, Akira; Cresswell, Andrew G

    2015-01-01

    We have proposed a muscle model which consists of two Maxwell elements and a Voigt element in parallel. The muscle model was applied on the experiment of the force responses by the fast ramp stretch in muscle fibres to determine the mechanical parameters. In the simulation, the Maxwell element with a flexible spring and a long relaxation time seemed to correspond with the force-generating state of the cross-bridges. Next, we tried the muscle model to simulate the relatively slow movement. Experimentally, we have measured torque changes by the stretch responses in the human triceps surae. In the experiments, the derivation of torque by rotation angle showed two peaks P1 and P2. The first peak P1 originated from the elastic properties of engaged cross-bridges, while the second peak P2 was due to stretch reflex signals. The model of a single-joint system simulated well with the experimental results to show a good adaptability of the muscle model.

  17. Reflex pathways connect receptors in the human lower leg to the erector spinae muscles of the lower back.

    Science.gov (United States)

    Clair, J M; Okuma, Y; Misiaszek, J E; Collins, D F

    2009-06-01

    Reflex pathways connect all four limbs in humans. Presently, we tested the hypothesis that reflexes also link sensory receptors in the lower leg with muscles of the lower back (erector spinae; ES). Taps were applied to the right Achilles' tendon and electromyographic activity was recorded from the right soleus and bilaterally from ES. Reflexes were compared between sitting and standing and between standing with the eyes open versus closed. Reflexes were evoked bilaterally in ES and consisted of an early latency excitation, a medium latency inhibition, and a longer latency excitation. During sitting but not standing, the early excitation was larger in the ES muscle ipsilateral to the stimulation (iES) than in the contralateral ES (cES). During standing but not sitting, the longer latency excitation in cES was larger than in iES. This response in cES was also larger during standing compared to sitting. Responses were not significantly different between the eyes open and eyes closed conditions. Taps applied to the lateral calcaneus (heel taps) evoked responses in ES that were not significantly different in amplitude or latency than those evoked by tendon taps, despite a 75-94% reduction in the amplitude of the soleus stretch reflex evoked by the heel taps. Electrical stimulation of the sural nerve, a purely cutaneous nerve at the ankle, evoked ES reflexes that were not significantly different in amplitude but had significantly longer latencies than those evoked by the tendon and heel taps. These results support the hypothesis that reflex pathways connect receptors in the lower leg with muscles of the lower back and show that that the amplitude of these reflexes is modulated by task. Responses evoked by stimulation of the sural nerve establish that reflex pathways connect the ES muscles with cutaneous receptors of the foot. In contrast, the large volley in muscle spindle afferents induced by the tendon taps compared to the heel taps did not alter the ES responses

  18. Capillary stretching of elastic fibers

    Science.gov (United States)

    Protiere, Suzie; Stone, Howard A.; Duprat, Camille

    2014-11-01

    Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.

  19. [Urinary urgency and reflex incontinence].

    Science.gov (United States)

    Madersbacher, H

    1991-07-01

    Urge and reflex incontinence are caused by detrusor dysfunction:urgency may be due to hyperactivity or hypersensitivity of the bladder. Neurogenic hyperactivity of the detrusor is called detrusor hyperreflexia: the neurogenic uninhibited bladder is caused by incomplete, and the so-called reflex bladder by complete, suprasacral lesions. The pathophysiology of symptomatic and idiopathic detrusor hyperactivity and the therapeutic armentarium are described. Bladder drill together with biofeedback and pharmacotherapy with spasmolytic drugs - several potent spasmolytic drugs with different modes of action are available - are the basis of treatment for hyperactivity and hypersensitivity of the detrusor. An alternative is electrostimulation: stimulation of the afferents of the pudendal nerve, via the pelvic floor (anal, vaginal), percutaneously (dorsal nerve of the penis, clitoric nerve) or by the implantation of electrodes results in inhibition of the detrusor. Most (80-90%) patients can be treated successfully by conservative means. Operative measurements comprise bladder denervation and bladder augmentation. The results of bladder denervation by transtrigonal phenolization of the pelvic plexus are highly controversial. In patients with uncontrollable hyperactivity of the detrusor, augmentation of the bladder (e.g. clam ileocystoplasty) is the method of choice, while for those with uncontrollable hypersensitivity of the detrusor, cystectomy followed by bladder substitution should be performed as a last resort. Treatment for urinary incontinence due to detrusor hyperreflexia must be selected bearing in mind that bladder emptying is inadequate, in most cases because of dyssynergia between detrusor and external sphincter. Therapy is basically aimed at transforming hyperreflexia of the detrusor into hyporeflexia, primarily by potent spasmolytic drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Does Acute Static Stretching Reduce Muscle Power?

    Directory of Open Access Journals (Sweden)

    Francis M. Kozub

    2012-12-01

    Full Text Available Context: Stretching is commonly used as a technique for injury prevention in the training and clinical setting. Recently, stretching in the warm-up has been shown to decrease several muscular performance variables, but the dose-response of this effect is unknown and moreover these stretching bouts are not representative of athletes during warm up procedures, as they are usually time consuming. Our findings may improve the understanding of the neuromuscular responses to stretching and help sportsmen, coaches, physiotherapist and clinicians make decisions for integrating stretching as a part of warm up or rehabilitation treatment plan.Purpose: The aim of the present study was to examine whether acute static stretching is responsible for losses in isokinetic peak torque production and if it does, than which time of stretching effect muscle peak torque?Design: Randomized, counterbalanced, within-subjects experimental design.Setting: A university human project laboratory.Methods: Twenty (n=20 light to moderate young exercisers, male and female, from University of Limerick community, with an average age of 22.1±3.6 years, height of 175.6±5 cm, and weight of 73.1±9.9 kg, were randomly selected to take part in the study. Prior to the main study, volunteers attended the lab on two occasions to be familiarized with the knee extension protocol on the Con - trex isokinetic system and with the static stretching protocol. All participants than performed five additional static stretching protocols randomly, in non-consecutive training session. The stretching protocols were 0, 60,120, 180 and 180 with alternative pattern.Results: The results of the statistical analysis (P > 0.05 indicated that peak torque remained unchanged following the static stretching for 0-180 sec at 60 & 180° s−1 angular velocities.Conclusion: The findings suggest that an athletic stretching (shorter duration ranging from 0-180 sec does not produce decreases in peak torque. Athletes

  1. Cutaneous reflex modulation and self-induced reflex attenuation in cerebellar patients.

    Science.gov (United States)

    Hoogkamer, Wouter; Van Calenbergh, Frank; Swinnen, Stephan P; Duysens, Jacques

    2015-02-01

    Modulation of cutaneous reflexes is important in the neural control of walking, yet knowledge about underlying neural pathways is still incomplete. Recent studies have suggested that the cerebellum is involved. Here we evaluated the possible roles of the cerebellum in cutaneous reflex modulation and in attenuation of self-induced reflexes. First we checked whether leg muscle activity during walking was similar in patients with focal cerebellar lesions and in healthy control subjects. We then recorded cutaneous reflex activity in leg muscles during walking. Additionally, we compared reflexes after standard (computer triggered) stimuli with reflexes after self-induced stimuli for both groups. Biceps femoris and gastrocnemius medialis muscle activity was increased in the patient group compared with the control subjects, suggesting a coactivation strategy to reduce instability of gait. Cutaneous reflex modulation was similar between healthy control subjects and cerebellar patients, but the latter appeared less able to attenuate reflexes to self-induced stimuli. This suggests that the cerebellum is not primarily involved in cutaneous reflex modulation but that it could act in attenuation of self-induced reflex responses. The latter role in locomotion would be consistent with the common view that the cerebellum predicts sensory consequences of movement. Copyright © 2015 the American Physiological Society.

  2. Brainstem reflexes in patients with familial dysautonomia.

    Science.gov (United States)

    Gutiérrez, Joel V; Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

    2015-03-01

    Several distinctive clinical features of patients with familial dysautonomia (FD) including dysarthria and dysphagia suggest a developmental defect in brainstem reflexes. Our aim was to characterize the neurophysiological profile of brainstem reflexes in these patients. We studied the function of sensory and motor trigeminal tracts in 28 patients with FD. All were homozygous for the common mutation in the IKAP gene. Each underwent a battery of electrophysiological tests including; blink reflexes, jaw jerk reflex, masseter silent periods and direct stimulation of the facial nerve. Responses were compared with 25 age-matched healthy controls. All patients had significantly prolonged latencies and decreased amplitudes of all examined brainstem reflexes. Similar abnormalities were seen in the early and late components. In contrast, direct stimulation of the facial nerve revealed relative preservation of motor responses. The brainstem reflex abnormalities in FD are best explained by impairment of the afferent and central pathways. A reduction in the number and/or excitability of trigeminal sensory axons is likely the main problem. These findings add further evidence to the concept that congenital mutations of the elongator-1 protein (or IKAP) affect the development of afferent neurons including those carrying information for the brainstem reflex pathways. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Reflexivity and technology in adult learning

    Directory of Open Access Journals (Sweden)

    Neil Selwyn

    2005-03-01

    Full Text Available It is argued by influential commentators such as Ulrich Beck and Scott Lash that we now live in a ‘reflexively modern' age. People are seen to now be free of the structures of modern society and driven instead by individualised opportunities to reflexively engage with their fast-changing social worlds and identities. Taking the notion of reflexive modernisation as its starting point, this paper explores the roles that information technologies (ITs may play in supporting adults' reflexive judgements about, and reflexive engagements with, education and learning. Through an analysis of interview data with 100 adults in the UK the paper finds that whilst a minority of interviewees were using ITs to support and inform reflexive engagementwith learning, the majority of individuals relayed little sign of technology-supported reflexivity when it came to their (nonengagement with education. For most people ITs were found, at best, to reinforce pre-established tendencies to ‘drift' through the formal education system. The paper concludes by considering the implications of these findings for ongoing efforts in developed countries to establish technology-supported ‘learning societies'.

  4. Stretching micropatterned cells on a PDMS membrane.

    Science.gov (United States)

    Carpi, Nicolas; Piel, Matthieu

    2014-01-22

    Mechanical forces exerted on cells and/or tissues play a major role in numerous processes. We have developed a device to stretch cells plated on a PolyDiMethylSiloxane (PDMS) membrane, compatible with imaging. This technique is reproducible and versatile. The PDMS membrane can be micropatterned in order to confine cells or tissues to a specific geometry. The first step is to print micropatterns onto the PDMS membrane with a deep UV technique. The PDMS membrane is then mounted on a mechanical stretcher. A chamber is bound on top of the membrane with biocompatible grease to allow gliding during the stretch. The cells are seeded and allowed to spread for several hours on the micropatterns. The sample can be stretched and unstretched multiple times with the use of a micrometric screw. It takes less than a minute to apply the stretch to its full extent (around 30%). The technique presented here does not include a motorized device, which is necessary for applying repeated stretch cycles quickly and/or computer controlled stretching, but this can be implemented. Stretching of cells or tissue can be of interest for questions related to cell forces, cell response to mechanical stress or tissue morphogenesis. This video presentation will show how to avoid typical problems that might arise when doing this type of seemingly simple experiment.

  5. The Multiple Faces of Reflexive Research Designs

    Directory of Open Access Journals (Sweden)

    Karl H. Müller

    2015-10-01

    Full Text Available Reflexive research can be grouped into five clusters with circular relations between two elements x ↔ x, namely circular relations between observers, between scientific building blocks like concepts, theories or models, between systemic levels, between rules and rule systems or as circular relations or x ↔ y between these four components. By far the most important cluster is the second cluster which becomes reflexive through a re-entry operation RE into a scientific element x and which establishes its circular formation as x(x. Many of the research problems in these five clusters in reflexivity research are still unexplored and pose grand challenges for future research.

  6. Ranges of bimodule projections and reflexivity

    CERN Document Server

    Eleftherakis, G K

    2011-01-01

    We develop a general framework for reflexivity in dual Banach spaces, motivated by the question of when the weak* closed linear span of two reflexive masa-bimodules is automatically reflexive. We establish an affirmative answer to this question in a number of cases by examining two new classes of masa-bimodules, defined in terms of ranges of masa-bimodule projections. We give a number of corollaries of our results concerning operator and spectral synthesis, and show that the classes of masa-bimodules we study are operator synthetic if and only if they are strong operator Ditkin.

  7. Stretching and injury prevention: an obscure relationship.

    Science.gov (United States)

    Witvrouw, Erik; Mahieu, Nele; Danneels, Lieven; McNair, Peter

    2004-01-01

    It is generally accepted that increasing the flexibility of a muscle-tendon unit promotes better performances and decreases the number of injuries. Stretching exercises are regularly included in warm-up and cooling-down exercises; however, contradictory findings have been reported in the literature. Several authors have suggested that stretching has a beneficial effect on injury prevention. In contrast, clinical evidence suggesting that stretching before exercise does not prevent injuries has also been reported. Apparently, no scientifically based prescription for stretching exercises exists and no conclusive statements can be made about the relationship of stretching and athletic injuries. Stretching recommendations are clouded by misconceptions and conflicting research reports. We believe that part of these contradictions can be explained by considering the type of sports activity in which an individual is participating. Sports involving bouncing and jumping activities with a high intensity of stretch-shortening cycles (SSCs) [e.g. soccer and football] require a muscle-tendon unit that is compliant enough to store and release the high amount of elastic energy that benefits performance in such sports. If the participants of these sports have an insufficient compliant muscle-tendon unit, the demands in energy absorption and release may rapidly exceed the capacity of the muscle-tendon unit. This may lead to an increased risk for injury of this structure. Consequently, the rationale for injury prevention in these sports is to increase the compliance of the muscle-tendon unit. Recent studies have shown that stretching programmes can significantly influence the viscosity of the tendon and make it significantly more compliant, and when a sport demands SSCs of high intensity, stretching may be important for injury prevention. This conjecture is in agreement with the available scientific clinical evidence from these types of sports activities. In contrast, when the type

  8. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  9. △'-Reflexive Modules and Cogen(P)-Linear Compactness

    Institute of Scientific and Technical Information of China (English)

    Lin Xin

    2005-01-01

    In this paper, we introduce the notion of △'-reflexive modules. We investigate the reflexive modules with respect to a partial cotilting (bi)module and obtain a connection between △'-reflexive modules and Cogen(P)-linearly compact modules. The main results generalize the results on reflexive modules with respect to a cotilting bimodule.

  10. Springback Prediction and Optimization of Variable Stretch Force Trajectory in Three-dimensional Stretch Bending Process

    Institute of Scientific and Technical Information of China (English)

    TENG Fei; ZHANG Wanxi; LIANG Jicai; GAO Song

    2015-01-01

    Most of the existing studies use constant force to reduce springback while researching stretch force. However, variable stretch force can reduce springback more efficiently. The current research on springback prediction in stretch bending forming mainly focuses on artificial neural networks combined with the finite element simulation. There is a lack of springback prediction by support vector regression (SVR). In this paper, SVR is applied to predict springback inthe three-dimensional stretch bending forming process,and variable stretch force trajectory is optimized. Six parameters of variable stretch force trajectory are chosen as the input parameters of the SVR model. Sixty experiments generated by design of experiments (DOE) are carried out to train and test the SVR model. The experimental results confirm that the accuracy of the SVR model is higher than that of artificial neural networks. Based on this model, an optimization algorithm of variable stretch force trajectory using particle swarm optimization (PSO) is proposed. The springback amount is used as the objective function. Changes of local thickness are applied as the criterion of forming constraints. The objection and constraints are formulated by response surface models. The precision of response surface models is examined. Six different stretch force trajectories are employed to certify springback reduction in the optimum stretch force trajectory, which can efficiently reduce springback. This research proposes a new method of springback prediction using SVR and optimizes variable stretch force trajectory to reduce springback.

  11. Static Versus Dynamic Stretching Effect on Agility Performance

    OpenAIRE

    Troumbley, Patrick

    2010-01-01

    The purpose of this study was to compare effects of static and dynamic stretching on explosive agility movements, and to examine the effect of the interaction of dynamic and static stretching prior to explosive agility movements. Fourteen men and 10 women performed the different warm-up protocols, including no warm-up (NWU), static stretching (SS), dynamic stretching (DS), and dynamic stretching with static stretching (DS+SS). The T-Drill was used to assess agility. The results indicated n...

  12. Impaired H-Reflex Gain during Postural Loaded Locomotion in Individuals Post-Stroke.

    Directory of Open Access Journals (Sweden)

    Jing Nong Liang

    Full Text Available Successful execution of upright locomotion requires coordinated interaction between controllers for locomotion and posture. Our earlier research supported this model in the non-impaired and found impaired interaction in the post-stroke nervous system during locomotion. In this study, we sought to examine the role of the Ia afferent spinal loop, via the H-reflex response, under postural influence during a locomotor task. We tested the hypothesis that the ability to increase stretch reflex gain in response to postural loads during locomotion would be reduced post-stroke.Fifteen individuals with chronic post-stroke hemiparesis and 13 non-impaired controls pedaled on a motorized cycle ergometer with specialized backboard support system under (1 seated supported, and (2 non-seated postural-loaded conditions, generating matched pedal force outputs of two levels. H-reflexes were elicited at 90° crank angle.We observed increased H-reflex gain with postural influence in non-impaired individuals, but a lack of increase in individuals post-stroke. Furthermore, we observed decreased H-reflex gain at higher postural loads in the stroke-impaired group.These findings suggest an impaired Ia afferent pathway potentially underlies the defects in the interaction between postural and locomotor control post-stroke and may explain reduced ability of paretic limb support during locomotor weight-bearing in individuals post-stroke.These results support the judicious use of bodyweight support training when first helping individuals post-stroke to regain locomotor pattern generation and weight-bearing capability.

  13. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity

    Directory of Open Access Journals (Sweden)

    Karin Lienhard

    2015-01-01

    Full Text Available The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG spectrum recorded during whole-body vibration (WBV exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p < 0.05, and was significantly correlated to the sEMG signal without the spikes of the respective muscle (r range: 0.54 - 0.92, p < 0.05. This finding indicates that reflex activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity.

  14. Effect of modified hold-relax stretching and static stretching on hamstring muscle flexibility.

    Science.gov (United States)

    Ahmed, Hashim; Iqbal, Amir; Anwer, Shahnawaz; Alghadir, Ahmad

    2015-02-01

    [Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control groups. The modified hold-relax stretching group performed 7 seconds of isometric contraction and then relaxed for 5 seconds, and this was repeated five times daily for five consecutive days. The static stretching group received 10 minutes of static stretching with the help of a pulley and weight system for five consecutive days. The control group received only moist heat for 20 minutes for five consecutive days. A baseline reading of passive knee extension (PKE) was taken prior to the intervention; rest measurements were taken immediate post intervention on day 1, day 3, day 5, and after a 1 week follow-up, i.e., at the 12th day. [Results] On comparing the baseline readings of passive knee extension (PKE), there was no difference noted between the three groups. On comparing the posttest readings on day 5 between the 3 groups, a significant difference was noted. However, post hoc analysis revealed an insignificant difference between the modified hold-relax stretching and static stretching groups. There was a significant difference between the static stretching and control groups and between the modified hold-relax stretching and control groups. [Conclusion] The results of this study indicate that both the modified hold-relax stretching technique and static stretching are equally effective, as there was no significant difference in improving the hamstring muscle flexibility between the two groups.

  15. Entrepreneurship Teaching Conducted as Strategic Reflexive Conversation

    DEFF Research Database (Denmark)

    Kristiansson, Michael

    The paper intends exploring and ascertaining whether the concept of strategic reflexive conversation can profitably be applied to entrepreneurship. As a start, a process of conceptualisation is undertaken, which is instrumental in placing the notion of strategic reflexive conversation...... into a knowledge management perspective. Strategic reflexive conversation is presented in an enhanced and updated version, which is contrasted to entrepreneurship through reflection. The findings indicate and it can be concluded that, with some important reservations, strategic reflexive conversation can...... and empirical studies. No doubt the reported study can be enhanced and refined in a theoretical sense and be empirically supported. The paper addresses a potentially significant theme and aims to stimulate discussion, which can provide input and ideas for enhancing practice-oriented entrepreneurship...

  16. Portraying Reflexivity in Health Services Research.

    Science.gov (United States)

    Rae, John; Green, Bill

    2016-09-01

    A model is proposed for supporting reflexivity in qualitative health research, informed by arguments from Bourdieu and Finlay. Bourdieu refers to mastering the subjective relation to the object at three levels-the overall social space, the field of specialists, and the scholastic universe. The model overlays Bourdieu's levels of objectivation with Finlay's three stages of research (pre-research, data collection, and data analysis). The intersections of these two ways of considering reflexivity, displayed as cells of a matrix, pose questions and offer prompts to productively challenge health researchers' reflexivity. Portraiture is used to show how these challenges and prompts can facilitate such reflexivity, as illustrated in a research project. © The Author(s) 2016.

  17. Bias of purine stretches in sequenced chromosomes

    DEFF Research Database (Denmark)

    Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

    2002-01-01

    We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we...... measured the fraction of each genome which contains purine (or pyrimidine) tracts of lengths of 10 by or longer (hereafter referred to as 'purine tracts'), as well as stretches of alternating pyrimidines/purine ('pyr/pur tracts') of the same length. Using this criteria, a random sequence would be expected......, in eukaryotes there is an abundance of long stretches of purines or alternating purine/pyrimidine tracts, which cannot be explained in this way; these sequences are likely to play an important role in eukaryotic chromosome organisation....

  18. On the Second Language Acquisition of Spanish Reflexive Passives and Reflexive Impersonals by French- and English-Speaking Adults

    Science.gov (United States)

    Tremblay, Annie

    2006-01-01

    This study, a partial replication of Bruhn de Garavito (1999a; 1999b), investigates the second language (L2) acquisition of Spanish reflexive passives and reflexive impersonals by French- and English-speaking adults at an advanced level of proficiency. The L2 acquisition of Spanish reflexive passives and reflexive impersonals by native French and…

  19. Proprioceptive reaction times and long-latency reflexes in humans.

    Science.gov (United States)

    Manning, C D; Tolhurst, S A; Bawa, P

    2012-08-01

    The stretch of upper limb muscles results in two electromyographic (EMG) peaks, M1 and M2. The amplitude of M2 peak can generally be modified by giving prior instruction to the subject on how to react to the applied perturbation. The unresolved question is whether the amplitude modulation results from change in the gain of the reflex pathway contributing to M2, or by superposition of reaction time (RT) activity. The following study attempted to resolve this question by examining the overlap between proprioceptive RT and M2 activities. Subject's right wrist flexors were stretched, and he/she was instructed either (1) not to intervene (passive task) or (2) to react as fast as possible by simultaneously flexing both wrists (active or compensate task). Under passive and active conditions, M1 and M2 were observed from EMG of right wrist flexors, and during the active condition, RT activities were additionally observed from both sides. The onset and offset of M2 (M1(onset), M2(offset)) were measured from the passive averages, while the RT was measured from the averaged EMG response of the left wrist flexors. For between-subject correlations, the data were divided into two sets: (1) subjects with RT shorter than M2(offset) (fast group) and (2) subjects with RT more than 10 ms longer than their M2(offset) (slow group). Modulation during M2 period was large for the fast group, and it was almost zero for the slow group. These results indicate that the superimposition of RT activity mainly contributes to the instruction-dependent modulation of M2 peak.

  20. Reflexive convention: civil partnership, marriage and family.

    Science.gov (United States)

    Heaphy, Brian

    2017-09-14

    Drawing on an analysis of qualitative interview data from a study of formalized same-sex relationships (civil partnerships) this paper examines the enduring significance of marriage and family as social institutions. In doing so, it intervenes in current debates in the sociology of family and personal life about how such institutions are undermined by reflexivity or bolstered by convention. Against the backdrop of dominating sociological frames for understanding the links between the changing nature of marriage and family and same-sex relationship recognition, the paper analyses the diverse and overlapping ways (including the simple, relational, strategic, ambivalent and critical ways) in which same-sex partners reflexively constructed and engaged with marriage and family conventions. My analysis suggests that instead of viewing reflexivity and convention as mutually undermining, as some sociologists of family and personal life do, it is insightful to explore how diverse forms of reflexivity and convention interact in everyday life to reconfigure the social institutions of marriage and family, but do not undermine them as such. I argue the case for recognizing the ways in which 'reflexive convention', or reflexive investment in convention, contributes to the continuing significance of marriage and family as social institutions. © London School of Economics and Political Science 2017.

  1. The passive of reflexive verbs in Icelandic

    Directory of Open Access Journals (Sweden)

    Hlíf Árnadóttir

    2011-10-01

    Full Text Available The Reflexive Passive in Icelandic is reminiscent of the so-called New Passive (or New Impersonal in that the oblique case of a passivized object NP is preserved. As is shown by recent surveys, however, speakers who accept the Reflexive Passive do not necessarily accept the New Passive, whereas conversely, speakers who accept the New Passive do also accept the Reflexive Passive. Based on these results we suggest that there is a hierarchy in the acceptance of passive sentences in Icelandic, termed the Passive Acceptability Hierarchy. The validity of this hierarchy is confirmed by our diachronic corpus study of open access digital library texts from Icelandic journals and newspapers dating from the 19th and 20th centuries (tímarit.is. Finally, we sketch an analysis of the Reflexive Passive, proposing that the different acceptability rates of the Reflexive and New Passives lie in the argument status of the object. Simplex reflexive pronouns are semantically dependent on the verbs which select them, and should therefore be analyzed as syntactic arguments only, and not as semantic arguments of these verbs.

  2. Torso flexion modulates stiffness and reflex response.

    Science.gov (United States)

    Granata, K P; Rogers, E

    2007-08-01

    Neuromuscular factors that contribute to spinal stability include trunk stiffness from passive and active tissues as well as active feedback from reflex response in the paraspinal muscles. Trunk flexion postures are a recognized risk factor for occupational low-back pain and may influence these stabilizing control factors. Sixteen healthy adult subjects participated in an experiment to record trunk stiffness and paraspinal muscle reflex gain during voluntary isometric trunk extension exertions. The protocol was designed to achieve trunk flexion without concomitant influences of external gravitational moment, i.e., decouple the effects of trunk flexion posture from trunk moment. Systems identification analyses identified reflex gain by quantifying the relation between applied force disturbances and time-dependent EMG response in the lumbar paraspinal muscles. Trunk stiffness was characterized from a second order model describing the dynamic relation between the force disturbances versus the kinematic response of the torso. Trunk stiffness increased significantly with flexion angle and exertion level. This was attributed to passive tissue contributions to stiffness. Reflex gain declined significantly with trunk flexion angle but increased with exertion level. These trends were attributed to correlated changes in baseline EMG recruitment in the lumbar paraspinal muscles. Female subjects demonstrated greater reflex gain than males and the decline in reflex gain with flexion angle was greater in females than in males. Results reveal that torso flexion influences neuromuscular factors that control spinal stability and suggest that posture may contribute to the risk of instability injury.

  3. Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle.

    Science.gov (United States)

    Gulledge, Brett M; Marcellin-Little, Denis J; Levine, David; Tillman, Larry; Harrysson, Ola L A; Osborne, Jason A; Baxter, Blaise

    2014-02-01

    Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30-40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion.

  4. Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction.

    Science.gov (United States)

    Miyahara, Yutetsu; Naito, Hisashi; Ogura, Yuji; Katamoto, Shizuo; Aoki, Junichiro

    2013-01-01

    This study was undertaken to investigate and compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and static stretching on maximal voluntary contraction (MVC). Thirteen male university students (age, 20 ± 1 years; height, 172.2 ± 4.6 cm; weight, 68.4 ± 6.7 kg; mean ± SD) completed 3 different conditions on 3 nonconsecutive days in randomized order: static stretching (SS), PNF stretching (PNF), and no stretching (control, CON). Each condition consisted of a 5-minute rest accompanied by one of the following activities: (a) control, (b) SS, or (c) PNF stretching. The hip flexion range of motion (ROM) was evaluated immediately before and after the activity. The MVC of knee flexion was then measured. Surface electromyography was recorded from the biceps femoris and vastus lateralis muscles during MVC tests and stretching. Although increases in ROM were significantly greater after PNF than after SS (p stretching increases ROM more than SS, PNF stretching and SS is detrimental to isometric maximal strength.

  5. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    Directory of Open Access Journals (Sweden)

    Lynn Bar-On

    Full Text Available The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01. The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between

  6. Soleus H-Reflex Operant Conditioning Changes The H-Reflex Recruitment Curve

    Science.gov (United States)

    Thompson, Aiko K.; Chen, Xiang Yang; Wolpaw, Jonathan R.

    2012-01-01

    Introduction Operant conditioning can gradually change the human soleus H-reflex. The protocol conditions the reflex near M-wave threshold. This study examined its impact on the reflexes at other stimulus strengths. Methods H-reflex recruitment curves were obtained before and after a 24-session exposure to an up-conditioning (HRup) or down-conditioning (HRdown) protocol and were compared. Results In both HRup and HRdown subjects, conditioning affected the entire H-reflex recruitment curve. In 5 of 6 HRup and 3 of 6 HRdown subjects, conditioning elevated (HRup) or depressed (HRdown), respectively, the entire curve. In the other HRup subject or the other 3 HRdown subjects, the curve was shifted to the left or to the right, respectively. Discussion H-reflex conditioning does not simply change the H-reflex to a stimulus of particular strength; it also changes the H-reflexes to stimuli of different strengths. Thus, it is likely to affect many actions in which this pathway participates. PMID:23281107

  7. Loading and reflexes : the influence of body weight and active movements on reflex responses in humans

    NARCIS (Netherlands)

    Bastiaanse, Catharina Maria

    2003-01-01

    This thesis describes six studies on the influence of active movements and body loading on reflex responses. To measure those influences healthy subjects were asked to walk with different loadings (e.g. a backpack) or with different active movements (e.g. arm swing) while different reflex responses

  8. Characteristics of the vibratory reflex in humans with reduced suprasegmental influence due to spinal cord injury.

    Science.gov (United States)

    Sherwood, A M; Dimitrijevic, M R; Bacia, T; McKay, W B

    1993-01-01

    The tonic stretch reflex elicited by vibration of a muscle or tendon provides a means of studying segmental reflex activity in humans with impaired volitional motor activity due to spinal cord injury (SCI). Vibration applied to the achilles or patellar tendon in a group of 51 SCI subjects elicited motor unit activity different from that found in 12 healthy subjects. Four distinct features of motor unit responses to vibration of a single tendon (achilles or patellar) could be seen in the SCI subjects: (i) a rapid onset, tonic response, frequently beginning with a single burst analogous to a tendon jerk, in 72% of vibrated sites; (ii) repetitive, phasic bursts of activity or vibratory-induced clonus in 23% of the tonic responses; (iii) spread of activity to muscles distant from the vibration in 44% of the tonic responses; and vibratory-induced withdrawal reflexes (VWR) which occurred after vibration of 37% of the sites. Overall, 81% of stimulated sites responded to vibration in SCI subjects. In contrast, only 54% of vibrated sites responded in control subjects, always with a gradual onset tonic response, never accompanied by a VWR. The VWR in SCI subjects was typically of much larger amplitude than the tonic responses and involved a mean of 5 muscles (41% bilaterally). Features of these responses provide an insight into underlying neurocontrol mechanisms which may provide guidance in the selection of appropriate intervention or management strategies.

  9. The trigemino-cervical reflex in normal subjects.

    Science.gov (United States)

    Milanov, I; Bogdanova, D; Ishpekova, B

    2001-01-01

    There are only few reports on the trigemino-cervical reflex in humans and there is debate over the best method of reflex examination. The aim of this study was, comparing different methods, to provide a reproducible method for evaluating the trigemino-cervical reflex. The trigemino-cervical reflex was studied in 32 healthy volunteers. The stimulation was applied to the supraorbital, infraorbital or mental nerve. Recordings were performed bilaterally from the sternocleidomastoid and trapezius muscles at rest. The reflex was also examined during maximal voluntary contraction of the sternocleidomastoid muscle after supraorbital nerve stimulation. It presented as a two-component reflex if recorded from a tonically active muscle and as a one-component reflex if recorded from a relaxed muscle. The most reproducible reflex responses were obtained from the resting sternocleidomastoid muscle after stimulation of the supraorbital nerve. In conclusion, the trigemino-cervical reflex may be most easily obtained from the relaxed sternocleidomastoid muscle after supraorbital nerve stimulation.

  10. An Analysis of Individual Stretching Programs of Intercollegiate Athletes.

    Science.gov (United States)

    Levine, Michael; And Others

    1987-01-01

    To evaluate individual stretching programs of intercollegiate athletes, 238 athletes (164 male, 74 female) in ten sports were surveyed about their stretching practices. Almost all of the athletes stretched, but to varying degrees. Muscle groups stretched by the fewest athletes were the adductors, plantar flexors, hips, and neck. (Author/MT)

  11. Warming-up and stretching for improved physical performance and prevention of sports-related injuries.

    Science.gov (United States)

    Shellock, F G; Prentice, W E

    1985-01-01

    end-points in the range of motion. Dynamic flexibility refers to the degree which a joint can be moved as a result of a muscle contraction and may therefore not be a good indicator of stiffness or looseness of a joint. There are 3 basic categories of stretching techniques: (a) ballistic--which makes use of repetitive bouncing movements; (b) static--which stretches the muscle to the point of slight muscle discomfort and is held for an extended period; and (c) proprioceptive neuromuscular facilitation - which uses alternating contractions and stretching of the muscles. Each of these stretching methods is based on the neurophysiological phenomenon involving the stretch reflex.(ABSTRACT TRUNCATED AT 400 WORDS)

  12. Stretch-activated channels in stretch-induced muscle damage: role in muscular dystrophy.

    Science.gov (United States)

    Yeung, Ella W; Allen, David G

    2004-08-01

    1. Stretch-induced muscle injury results in the damage that causes reduced force and increased membrane permeability. This muscle damage is caused, in part, by ionic entry through stretch-activated channels and blocking these channels with Gd3+ or streptomycin reduces the force deficit associated with damage. 2. Dystrophin-deficient muscles are more susceptible to stretch-induced muscle injury and the recovery from injury can be incomplete. We have found that Na+ entry associated with stretch-induced injury is enhanced in dystrophin-deficient muscles and that blockers of stretch-activated channels are capable of preventing ionic entry and reducing muscle damage. 3. A model is presented that proposes links between stretch-induced injury, opening of stretch-activated channels, increased levels of intracellular ions and various forms of muscle damage. Although changes in Na+ accompany stretch-induced muscle injury, we believe that changes in Ca2+ probably have a more central role in the damage process.

  13. What Protects Certain Nerves from Stretch Injury?

    Science.gov (United States)

    Schraut, Nicholas B; Walton, Sharon; Bou Monsef, Jad; Shott, Susan; Serici, Anthony; Soulii, Lioubov; Amirouche, Farid; Gonzalez, Mark H; Kerns, James M

    2016-01-01

    The human tibial nerves is less prone to injury following joint arthroplasty compared with the peroneal nerves. Besides the anatomical distribution, other features may confer protection from stretch injury. We therefore examined the size, shape and connective tissue distribution for the two nerves. The tibial and peroneal nerves from each side of nine fresh human cadavers we reharvested mid-thigh. Proximal segments manually stretched 20%-25% were fixed in aldehyde, while the adjacent distal segments were fixed in their natural length. Paraffin sections stained by Masson's trichrome method for connective tissue were examined by light microscopy. Tibial nerves had 2X more fascicles compared with the peroneal, but the axonal content appeared similar. Analysis showed that neither nerve had a significant reduction in cross sectional area of the fascicles following stretch. However, fascicles from stretched tibial nerves become significantly more oval compared with those from unstretched controls and peroneal nerves. Tibial nerves had a greater proportion that was extrafascicular tissue (50-55%) compared with peroneal nerves (38%-42%). This epineurium was typically adipose tissue. Perineurial thickness in both nerves was directly related to fascicular size. Tibial nerves have several unique histological features associated with size, shape and tissue composition compared with the peroneal nerve. We suggest that more fascicles with their tightly bound perineurium and more robust epineurium afford protection against stretch injury. Mechanical studies should clarify how size and shape contribute to nerve protection and/or neurapraxia.

  14. Movement and stretching imagery during flexibility training.

    Science.gov (United States)

    Vergeer, Ineke; Roberts, Jenny

    2006-02-01

    The aim of this study was to examine the effect of movement and stretching imagery on increases in flexibility. Thirty volunteers took part in a 4 week flexibility training programme. They were randomly assigned to one of three groups: (1) movement imagery, where participants imagined moving the limb they were stretching; (2) stretching imagery, where participants imagined the physiological processes involved in stretching the muscle; and (3) control, where participants did not engage in mental imagery. Active and passive range of motion around the hip was assessed before and after the programme. Participants provided specific ratings of vividness and comfort throughout the programme. Results showed significant increases in flexibility over time, but no differences between the three groups. A significant relationship was found, however, between improved flexibility and vividness ratings in the movement imagery group. Furthermore, both imagery groups scored significantly higher than the control group on levels of comfort, with the movement imagery group also scoring significantly higher than the stretching imagery group. We conclude that the imagery had stronger psychological than physiological effects, but that there is potential for enhancing physiological effects by maximizing imagery vividness, particularly for movement imagery.

  15. Using ESO Reflex with Web Services

    Science.gov (United States)

    Järveläinen, P.; Savolainen, V.; Oittinen, T.; Maisala, S.; Ullgrén, M. Hook, R.

    2008-08-01

    ESO Reflex is a prototype graphical workflow system, based on Taverna, and primarily intended to be a flexible way of running ESO data reduction recipes along with other legacy applications and user-written tools. ESO Reflex can also readily use the Taverna Web Services features that are based on the Apache Axis SOAP implementation. Taverna is a general purpose Web Service client, and requires no programming to use such services. However, Taverna also has some restrictions: for example, no numerical types such integers. In addition the preferred binding style is document/literal wrapped, but most astronomical services publish the Axis default WSDL using RPC/encoded style. Despite these minor limitations we have created simple but very promising test VO workflow using the Sesame name resolver service at CDS Strasbourg, the Hubble SIAP server at the Multi-Mission Archive at Space Telescope (MAST) and the WESIX image cataloging and catalogue cross-referencing service at the University of Pittsburgh. ESO Reflex can also pass files and URIs via the PLASTIC protocol to visualisation tools and has its own viewer for VOTables. We picked these three Web Services to try to set up a realistic and useful ESO Reflex workflow. They also demonstrate ESO Reflex abilities to use many kind of Web Services because each of them requires a different interface. We describe each of these services in turn and comment on how it was used

  16. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    Science.gov (United States)

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation. PMID:22319684

  17. Homologous pairing in stretched supercoiled DNA

    Science.gov (United States)

    Strick, T. R.; Croquette, V.; Bensimon, D.

    1998-01-01

    By using elastic measurements on single DNA molecules, we show that stretching a negatively supercoiled DNA activates homologous pairing in physiological conditions. These experiments indicate that a stretched unwound DNA locally denatures to alleviate the force-driven increase in torsional stress. This is detected by hybridization with 1 kb of homologous single-stranded DNA probes. The stretching force involved (≈2 pN) is small compared with those typically developed by molecular motors, suggesting that this process may be relevant to DNA processing in vivo. We used this technique to monitor the progressive denaturation of DNA as it is unwound and found that distinct, stable denaturation bubbles formed, beginning in A+T-rich regions. PMID:9724746

  18. Binary-phase compression of stretched pulses

    Science.gov (United States)

    Lozovoy, Vadim V.; Nairat, Muath; Dantus, Marcos

    2017-10-01

    Pulse stretching and compression are essential for the energy scale-up of ultrafast lasers. Here, we consider a radical approach using spectral binary phases, containing only two values (0 and π) for stretching and compressing laser pulses. We numerically explore different strategies and present results for pulse compression of factors up to a million back to the transform limit and experimentally obtain results for pulse compression of a factor of one hundred, in close agreement with numerical calculations. Imperfections resulting from binary-phase compression are addressed by considering cross-polarized wave generation filtering, and show that this approach leads to compressed pulses with contrast ratios greater than ten orders of magnitude. This new concept of binary-phase stretching and compression, if implemented in a multi-layer optic, could eliminate the need for traditional pulse stretchers and more importantly expensive compressors.

  19. Lattice stretching bistability and dynamic heterogeneity

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Savin, A. V.; Zolotaryuk, A. V.

    2012-01-01

    A simple one-dimensional lattice model is suggested to describe the experimentally observed plateau in force-stretching diagrams for some macromolecules. This chain model involves the nearest-neighbor interaction of a Morse-like potential (required to have a saturation branch) and a harmonic second......-neighbor coupling. Under an external stretching applied to the chain ends, the intersite Morse-like potential results in the appearance of a double-well potential within each chain monomer, whereas the interaction between the second neighbors provides a homogeneous bistable (degenerate) ground state, at least...... stretched bonds with a double-well potential. This case allows us to explain the existence of a plateau in the force-extension diagram for DNA and α-helix protein. Finally, the soliton dynamics are studied in detail....

  20. COMPUTER SIMULATION SYSTEM OF STRETCH REDUCING MILL

    Institute of Scientific and Technical Information of China (English)

    B.Y. Sun; S.J. Yuan

    2007-01-01

    The principle of the stretch reducing process is analyzed and three models of pass design areestablished. The simulations are done about variables, such as, stress, strain, the stretches betweenthe stands, the size parameters of the steel tube, and the roll force parameters. According to itsproduct catalogs the system can automatically divide the pass series, formulate the rolling table,and simulate the basic technological parameters in the stretch reducing process. All modules areintegrated based on the developing environment of VB6. The system can draw simulation curvesand pass pictures. Three kinds of database including the material database, pass design database,and product database are devised using Microsoft Access, which can be directly edited, corrected,and searched.

  1. The effect of elbow position on biceps tendon reflex

    Directory of Open Access Journals (Sweden)

    Keles Isik

    2004-07-01

    Full Text Available Background: Testing of tendon (T reflex is the basic method used in the diagnostic procedure of clinical neurology. Measurement of T reflexes precisely can be a valuable adjunct to clinical examination. Quantification of T reflexes may provide more accurate results. Aims: To analyze the effect of elbow position on biceps T reflex. Settings and Design: A self-controlled clinical trial of biceps T reflex testing at the Electrophysiology Unit of the Department of Physical Medicine and Rehabilitation. Methods and Materials: Biceps T reflex was obtained utilizing a hand-held electronic reflex hammer in 50 extremities of 25 healthy volunteers and the effect of elbow position (at 90°, 120° and 150° on reflex response was evaluated. Statistical Analysis: Repeated-measures analysis of variance by the General Linear Model and Pearson correlation test procedures. Results: Onset latency was significantly shorter at 120° of elbow position. The maximum amplitude value of biceps T reflex was obtained at 90° of elbow position. Onset latency of the reflex correlated significantly with the height and arm length but not with age. Conclusions: The electrophysiological measurement of T reflexes is an easy and useful method in the quantification of reflexes, supplying more objective data. However, when performing T reflex studies, the position of the extremity should be taken into consideration to achieve more reliable results.

  2. Filament stretching rheometer: inertia compensation revisited

    DEFF Research Database (Denmark)

    Szabo, Peter; McKinley, Gareth H.

    2003-01-01

    The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end of the e......The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end...

  3. Stretching and folding mechanism in foams

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, Alberto [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)], E-mail: tufaile@usp.br; Pedrosa Biscaia Tufaile, Adriana [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)

    2008-10-13

    We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board.

  4. Depicting Vortex Stretching and Vortex Relaxing Mechanisms

    Institute of Scientific and Technical Information of China (English)

    符松; 李启兵; 王明皓

    2003-01-01

    Different from many existing studies on the paranetrization of vortices, we investigate the effectiveness of two new parameters for identifying the vortex stretching and vortex relaxing mechanisms. These parameters are invariants and identify three-dimensional flow structures only, i.e. they diminish in two-dimensional flows. This is also unlike the existing vortex identification approaches which deliver information in two-dimensional flows. The present proposals have been successfully applied to identify the stretching and relaxing vortices in compressible mixing layers and natural convection flows.

  5. Viscous Swirling Flow over a Stretching Cylinder

    Institute of Scientific and Technical Information of China (English)

    Tiegang FANG; ShanshanYAO

    2011-01-01

    We investigate a viscous How over a cylinder with stretching and torsional motion. There is an exact solution to the Navier-Stokes equations and there exists a unique solution for all the given values of the flow Reynolds number. The results show that velocity decays faster for a higher Reynolds number and the How penetrates shallower into the ambient Huid. All the velocity proHles decay algebraically to the ambient zero velocity.%We investigate a viscous flow over a cylinder with stretching and torsional motion.There is an exact solution to the Navier-Stokes equations and there exists a unique solution for all the given values of the flow Reynolds number.The results show that velocity decays faster for a higher Reynolds number and the flow penetrates shallower into the ambient fluid.All the velocity profiles decay algebraically to the ambient zero velocity.Exact solutions of the Navier-Stokes (NS) equations play important roles in the development of fluid mechanics.In the review articles,[1,2] Wang summarized the available exact solutions of the unsteady state and of the steady-state NS equations.Swirl flows have important engineering applications in many fields such as the cyclone for separation of solid,liquid and gas,swirl atomizers,swirl combustion devices,heat transfer enhancement and others.[3,4] A famous example of flows involving rotation or swirl is the rotating disk problem studied by von Karman.[5-8] The flow induced by a stretching boundary is also important in the extrusion processes in plastic and metal industries.[9-11] Crane[12] presented an exact solution of the two-dimensional NS equations for a stretching sheet problem with a closed analytical form.The stretching wall problem was extended by Wang[13]to a three-dimensional setting.The flow between two stretching disks was studied by Fang and Zhang recently.[14] The combined effects of disk stretching and rotation on the von Karman flow was investigated by Fang.[15] The flow inside a channel or a

  6. Reflexive Planning as Design and Work

    DEFF Research Database (Denmark)

    Lissandrello, Enza; Grin, John

    2011-01-01

    In recent years, planning theorists have advanced various interpretations of the notion of reflexivity, inspired by American pragmatism, complexity theory, hermeneutics, discursive and collaborative planning. Scholars agree that “reflexivity” has a strong temporal dimension: it not only aims...... to solve present planning problems, but to imagine and understand alternative trajectories for future action. This article explores the practical utility of reflexivity for planners, through a case study that focuses on a project to promote sustainable development in the Port of Amsterdam. Reflexivity...... in planning emerges as a new tool for generating critical knowledge and dialogue that can synthesise the perspectives of multiple actors in a common understanding, existing structural constraints and a collective imagination of alternative future possibilities. Such research highlights the potential...

  7. Human investigations into the exercise pressor reflex

    DEFF Research Database (Denmark)

    Secher, Niels H; Amann, Markus

    2012-01-01

    During exercise, neural input from skeletal muscles reflexly maintains or elevates blood pressure (BP) despite a maybe fivefold increase in vascular conductance. This exercise pressor reflex is illustrated by similar heart rate (HR) and BP responses to electrically induced and voluntary exercise....... The importance of the exercise pressor reflex for tight cardiovascular regulation during dynamic exercise is supported by studies using pharmacological blockade of lower limb muscle afferent nerves. These experiments show attenuation of the increase in BP and cardiac output when exercise is performed...... of an increase in BP during exercise with paralysed legs manifests, although electrical stimulation of muscles enhances lactate release and reduces muscle glycogen. Thus, the exercise pressor reflex enhances sympathetic activity and maintains perfusion pressure by restraining abdominal blood flow, while brain...

  8. Reflexive Planning as Design and Work

    DEFF Research Database (Denmark)

    Lissandrello, Enza; Grin, John

    2011-01-01

    In recent years, planning theorists have advanced various interpretations of the notion of reflexivity, inspired by American pragmatism, complexity theory, hermeneutics, discursive and collaborative planning. Scholars agree that “reflexivity” has a strong temporal dimension: it not only aims...... to solve present planning problems, but to imagine and understand alternative trajectories for future action. This article explores the practical utility of reflexivity for planners, through a case study that focuses on a project to promote sustainable development in the Port of Amsterdam. Reflexivity...... in planning emerges as a new tool for generating critical knowledge and dialogue that can synthesise the perspectives of multiple actors in a common understanding, existing structural constraints and a collective imagination of alternative future possibilities. Such research highlights the potential...

  9. Reflexive structures an introduction to computability theory

    CERN Document Server

    Sanchis, Luis E

    1988-01-01

    Reflexive Structures: An Introduction to Computability Theory is concerned with the foundations of the theory of recursive functions. The approach taken presents the fundamental structures in a fairly general setting, but avoiding the introduction of abstract axiomatic domains. Natural numbers and numerical functions are considered exclusively, which results in a concrete theory conceptually organized around Church's thesis. The book develops the important structures in recursive function theory: closure properties, reflexivity, enumeration, and hyperenumeration. Of particular interest is the treatment of recursion, which is considered from two different points of view: via the minimal fixed point theory of continuous transformations, and via the well known stack algorithm. Reflexive Structures is intended as an introduction to the general theory of computability. It can be used as a text or reference in senior undergraduate and first year graduate level classes in computer science or mathematics.

  10. Orthodoxy and reflexivity in international comparative analysis

    DEFF Research Database (Denmark)

    Lind, Jens; Valkenburg, Ben

    2002-01-01

    project, in which we have tried to deal with these consequences. Fourth, and hopefully as a result of the first three aims, we want to argue that a reflexive approach of international, comparative research is not only desirable, but attainable as well. In order to do so, we begin with a short discussion...... upon the consequences on the level of empirical research. We want to avoid that, so our second and third subject will be the practical implications of reflexivity for empirical research as well as for social policy. Our discussion on these subjects is based on the practical experiences in the INPART...... on the main issues in the so-called ?reflexive approach? and consider the main consequences of this approach for both social science and social policy. Against this background we will discuss the implications for comparative research and the experiences of the INPART project end up with a few central issues...

  11. Receptor mechanisms underlying heterogenic reflexes among the triceps surae muscles of the cat.

    Science.gov (United States)

    Nichols, T R

    1999-02-01

    The soleus (S), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles of the cat are interlinked by rapid spinal reflex pathways. In the decerebrate state, these heterogenic reflexes are either excitatory and length dependent or inhibitory and force dependent. Mechanographic analysis was used to obtain additional evidence that the muscle spindle primary ending and the Golgi tendon organ provide the major contributions to these reflexes, respectively. The tendons of the triceps surae muscles were separated and connected to independent force transducers and servo-controlled torque motors in unanesthetized, decerebrate cats. The muscles were activated as a group using crossed-extension reflexes. Electrical stimulation of the caudal cutaneous sural nerve was used to provide a particularly strong activation of MG and decouple the forces of the triceps surae muscles. During either form of activation, the muscles were stretched either individually or in various combinations to determine the strength and characteristics of autogenic and heterogenic feedback. The corresponding force responses, including both active and passive components, were measured during the changing background tension. During activation of the entire group, the excitatory, heterogenic feedback linking the three muscles was found to be strongest onto LG and weakest onto MG, in agreement with previous results concerning the strengths of heteronymous Ia excitatory postsynaptic potentials among the triceps surae muscles. The inhibition, which is known to affect only the soleus muscle, was dependent on active contractile force and was detected essentially as rapidly as length dependent excitation. The inhibition outlasted the excitation and was blocked by intravenous strychnine. These results indicate that the excitatory and inhibitory effects are dominated by feedback from primary spindle receptors and Golgi tendon organs. The interactions between these two feedback pathways potentially can

  12. New molecular knowledge towards the trigemino-cardiac reflex as a cerebral oxygen-conserving reflex.

    Science.gov (United States)

    Sandu, N; Spiriev, T; Lemaitre, F; Filis, A; Schaller, B

    2010-05-04

    The trigemino-cardiac reflex (TCR) represents the most powerful of the autonomous reflexes and is a subphenomenon in the group of the so-called "oxygen-conserving reflexes". Within seconds after the initiation of such a reflex, there is a powerful and differentiated activation of the sympathetic system with subsequent elevation in regional cerebral blood flow (CBF), with no changes in the cerebral metabolic rate of oxygen (CMRO2) or in the cerebral metabolic rate of glucose (CMRglc). Such an increase in regional CBF without a change of CMRO2 or CMRglc provides the brain with oxygen rapidly and efficiently. Features of the reflex have been discovered during skull base surgery, mediating reflex protection projects via currently undefined pathways from the rostral ventrolateral medulla oblongata to the upper brainstem and/or thalamus, which finally engage a small population of neurons in the cortex. This cortical center appears to be dedicated to transduce a neuronal signal reflexively into cerebral vasodilatation and synchronization of electrocortical activity; a fact that seems to be unique among autonomous reflexes. Sympathetic excitation is mediated by cortical-spinal projection to spinal preganglionic sympathetic neurons, whereas bradycardia is mediated via projections to cardiovagal motor medullary neurons. The integrated reflex response serves to redistribute blood from viscera to the brain in response to a challenge to cerebral metabolism, but seems also to initiate a preconditioning mechanism. Previous studies showed a great variability in the human TCR response, in special to external stimuli and individual factors. The TCR gives, therefore, not only new insights into novel therapeutic options for a range of disorders characterized by neuronal death, but also into the cortical and molecular organization of the brain.

  13. Stuttering or reflex seizure? A case report.

    Science.gov (United States)

    Michel, Véronique; Burbaud, Pierre; Taillard, Jacques; Gaida, Tsouria; Joseph, Pierre Alain; Duché, Bernard; Bioulac, Bernard

    2004-09-01

    Stuttering is characterized by involuntary syllabic repetitions and interruption in the smooth flow of speech. The exact cause of primary stuttering remains a matter of debate but a frontal dysfunction has been evoked. On the other hand, acquired stuttering is uncommon. We report a case of reflex epilepsy in which seizures were triggered by reading aloud or stressful conversation. Each paroxysmal event in left frontal region was associated clinically with a language disorder mimicking stuttering. Our observation suggests that reflex frontal focal epilepsy could be a putative etiology for acquired stuttering.

  14. [The vegetative component of a conditioned reflex].

    Science.gov (United States)

    Ordzhonikadze, Ts A; Pkhakadze, L D

    1975-01-01

    Defensive and alimentary conditioned reflexes were studied on normal cats and cats with neural isolation of the neocortex. The cardiac component of the conditioned reflexes is elaborated in decorticated animals at a similar rate and is as steady as in normal cats. Motor conditioned reactions in decorticated cats are difficult to elaborate. Both in normal and decorticated cats unconditioned pain stimulation evokes tachycardia, while a conditioned signal, paired with this unconditioned stimulus, produces bradicardia. Ban assumption has been made that the primary conditioned reaction consists in the appearance of a certain emotional state which changes the cardiac rhythm in a typical way.

  15. Strain and load thresholds for cervical muscle recruitment in response to quasi-static tensile stretch of the caprine C5-C6 facet joint capsule.

    Science.gov (United States)

    Azar, Nadia R; Kallakuri, Srinivasu; Chen, Chaoyang; Lu, Ying; Cavanaugh, John M

    2009-12-01

    The aim of this study was to investigate the response of cervical muscles to physiologic tensile stretch of cervical facet joint capsule (FJC) at a quasi-static displacement rate of 0.5mm/s. In vivo caprine left C5-C6 FJC preparations were subjected to an incremental tensile displacement paradigm. EMG activity was recorded during FJC stretch from the right trapezius (TR) and multifidus (MF) muscle groups at the C5 and C6 levels and bilaterally from the sternomastoid (SM) and longus colli (LC) muscle groups at the C5-C6 level. Onset of muscular activity was later analyzed using visual and computer-based methods. Capsule load and strain at the time of onset were recorded and compared between the muscle groups. Results indicated capsule load was a better indicator of the tensile stretch thresholds for muscular recruitment than capsule strain. MF responded at significantly smaller capsule loads than TR and LC, while TR and LC activation loads were not significantly different. SM did not respond to physiologic FJC stretch. Muscle group recruitment order reflected the muscles' fiber type compositions and functional roles in the spine. This study provides the first evidence that the cervical ligamento-muscular reflex pathways are activated via tensile FJC stretch and extend to superficial and deep musculature on the anterior and posterior aspects of the neck, ipsilateral and contralateral to the side of FJC stretch.

  16. Charitable giving and reflexive individuals: How personal reflexivity mediates between structure and agency.

    Science.gov (United States)

    Sanghera, Balihar

    2017-03-01

    This article examines how individuals are reflexive beings who interpret the world in relation to things that matter to them, and how charitable acts are evaluated and embedded in their lives with different degrees of meaning and importance. Rather than framing the discussion of charitable practices in terms of an altruism/egoism binary or imputing motivations and values to social structures, the article explains how reflexivity is an important and neglected dimension of social practices, and how it interacts with sympathy, sentiments and discourses to shape giving. The study also shows that there are different modes of reflexivity, which have varied effects on charity and volunteering.

  17. How many theta roles in a reflexive verb?

    NARCIS (Netherlands)

    Dimitriadis, Alexis; Everaert, Martin

    2014-01-01

    While purely syntactic approaches to reflexivization have characterized reflexive verbs in terms of detransitivization, we show that there is a discrepancy between syntactic and semantic arity. Reflexive verbs are syntactically intransitive, but semantically they are two-place predicates: both

  18. Team Reflexivity and Innovation: The Moderating Role of Team Context

    OpenAIRE

    Dawson, J.; Schippers, M; M. West

    2012-01-01

    Team reflexivity, the extent to which teams collectively reflect upon and adapt their working methods and functioning, has been shown to be an important predictor of team outcomes, notably innovation. As described in the current article, the authors developed and tested a team-level contingency model of team reflexivity, work demands, and innovation. They argue that highly reflexive teams will be more innovative than teams low in reflexivity when facing a demanding work environment. A field s...

  19. Neutron Compton scattering studies of stretched polyethylene

    CERN Document Server

    Gabrys, B J; Mayers, J; Kalhoro, M S

    2002-01-01

    The mean kinetic energy of hydrogen and carbon atoms in unstretched and stretched polyethylene samples has been measured by neutron Compton scattering. The vibrational frequencies of the ground state and torsional energies have been calculated and compared with the existing data and calculations. The results obtained on deuterated and non-deuterated samples are compared. (orig.)

  20. Linear viscoelastic characterization from filament stretching rheometry

    DEFF Research Database (Denmark)

    Wingstrand, Sara Lindeblad; Alvarez, Nicolas J.; Hassager, Ole

    viscoelasticity well into the nonlinear regime. Therefore at present, complete rheological characterization of a material requires two apparatuses: a shear and an extensional rheometer. This work is focused on developing a linear viscoelastic protocol for the filament stretching rheometer (FSR) in order...

  1. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  2. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  3. Cloud Network Helps Stretch IT Dollars

    Science.gov (United States)

    Collins, Hilton

    2012-01-01

    No matter how many car washes or bake sales schools host to raise money, adding funds to their coffers is a recurring problem. This perpetual financial difficulty makes expansive technology purchases or changes seem like a pipe dream for school CIOs and has education technologists searching for ways to stretch money. In 2005, state K-12 school…

  4. Control of reflexive saccades following hemispherectomy.

    Science.gov (United States)

    Reuter-Lorenz, Patricia A; Herter, Troy M; Guitton, Daniel

    2011-06-01

    Individuals who have undergone hemispherectomy for treatment of intractable epilepsy offer a rare and valuable opportunity to examine the ability of a single cortical hemisphere to control oculomotor performance. We used peripheral auditory events to trigger saccades, thereby circumventing dense postsurgical hemianopia. In an antisaccade task, patients generated numerous unintended short-latency saccades toward contralesional auditory events, indicating pronounced limitations in the ability of a single hemicortex to exert normal inhibitory control over ipsilateral (i.e., contralesional) reflexive saccade generation. Despite reflexive errors, patients retained an ability to generate correct antisaccades in both directions. The prosaccade task revealed numerous contralesional express saccades, a robust contralesional gap effect, but the absence of both effects for ipsilesional saccades. These results indicate limits to the saccadic control capabilities following hemispherectomy: A single hemicortex can mediate antisaccades in both directions, but plasticity does not extend fully to the bilateral inhibition of reflexive saccades. We posit that these effects are due to altered control dynamics that reduce the responsivity of the superior colliculus on the intact side and facilitate the release of an auditory-evoked ocular grasp reflex into the blind hemifield that the intact hemicortex has difficulty suppressing.

  5. Dilemmas and Deliberations in Reflexive Ethnographic Research

    Science.gov (United States)

    Robinson, Janean Valerie

    2014-01-01

    This paper traces insights into the challenges and dilemmas experienced whilst researching students' interpretations and understandings of the Behaviour Management in Schools policy in Western Australia. Journal records, supported by student transcripts, are woven together in a reflexive ethnographic journey--from the beginning phase of…

  6. The Reflexive Modernization of Australian Universities

    Science.gov (United States)

    Pick, David

    2004-01-01

    The profound changes occurring in Australian higher education are viewed here in the context of the social, cultural, political and economic effects of globalization. Particular attention is paid to providing a theoretical foundation for understanding these effects using the reflexive modernization perspective. Highlighted are some of the…

  7. A reflexive perspective in problem solving

    Directory of Open Access Journals (Sweden)

    Chio, José Angel

    2013-01-01

    Full Text Available The objective of this paper is to favour the methodological process of reflexive analysis in problem solving in the general teaching methods that concentrates in strengthening the dimensional analysis, to gain a greater preparation of the students for the solution of mathematical problems.

  8. Taking Control of Reflexive Social Attention

    Science.gov (United States)

    Ristic, Jelena; Kingstone, Alan

    2005-01-01

    Attention is shifted reflexively to where other people are looking. It has been argued by a number of investigators that this social attention effect reflects the obligatory bottom-up activation of domain-specific modules within the inferior temporal (IT) cortex that are specialized for processing face and gaze information. However, it is also the…

  9. The reflexive self and culture: a critique.

    Science.gov (United States)

    Adams, Matthew

    2003-06-01

    This article attempts to engage with a tendency in the theorization of social change and self-identity, evident in the work of a number of contemporary social theorists, to place an extended process of reflexivity at the heart of modern identity. As symptomatic of 'neo-modern' accounts of selfhood, critical readings of Giddens, Beck, Castells and some aspects of social theory more generally, and their account of modern reflexivity's relationship to culture, are assessed. In light of these criticisms, ways in which culture might still play an important part in the shaping of identity are considered. The relationship between language, culture and reflexivity, drawing from philosophy, sociology and G. H. Mead's own brand of social psychology, are all utilized in establishing a critique of the role Giddens and others designate for culture in the constitution of the contemporary self. By potentially repositioning self-identity in its connection to culture, the overall bearing of reflexivity upon the processes of self-identity is thus questioned. It is argued that a culturally-situated, yet fluid and multifarious account of self-identity is a necessary analytical and normative alternative.

  10. A Testbed for Autonomous Reflexive Grasping

    Science.gov (United States)

    1993-03-01

    written in C. The tactile sensor is neural network causes the reflex layer of the a 10 x 10 Tekscan sensor with an active area subsumption architecture to...Doctoral Thesis, March 1990. [9] J. G. Webster, Tactile Sensors for Robotics and Medicine, John Wiley & Sons, 1988 [10] Tekscan Inc., " Tekscan Corporate

  11. Biological Motion Cues Trigger Reflexive Attentional Orienting

    Science.gov (United States)

    Shi, Jinfu; Weng, Xuchu; He, Sheng; Jiang, Yi

    2010-01-01

    The human visual system is extremely sensitive to biological signals around us. In the current study, we demonstrate that biological motion walking direction can induce robust reflexive attentional orienting. Following a brief presentation of a central point-light walker walking towards either the left or right direction, observers' performance…

  12. A Reflexive Model for Teaching Instructional Design.

    Science.gov (United States)

    Shambaugh, Neal; Magliaro, Susan

    2001-01-01

    Documents a five-year study of two instructors who collaborated on formally studying their teaching of a master's level instructional design course. Outlines their views on learning, teaching, and instructional design (ID), describes the ID course, and explains the reflexive instructional model used, in which the teachers examined their teaching…

  13. How to determine local stretching and tension in a flow-stretched DNA molecule

    Science.gov (United States)

    Pedersen, Jonas N.; Marie, Rodolphe; Kristensen, Anders; Flyvbjerg, Henrik

    2016-04-01

    We determine the nonuniform stretching of and tension in a mega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead, we analyze the transverse thermal motion of the DNA. Tension at the center of the DNA adds up to 16 pN, giving almost fully stretched DNA. This method was devised for optical mapping of DNA, specifically, DNA denaturation patterns. It may be useful also for other studies, e.g., DNA-protein interactions, specifically, their tension dependence. Generally, wherever long strands of DNA—e.g., native DNA extracted from human cells or bacteria—must be stretched with ease for inspection, this method applies.

  14. How to determine local stretching and tension in a flow-stretched DNA molecule

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Marie, Rodolphe; Kristensen, Anders

    2016-01-01

    We determine the nonuniform stretching of and tension in amega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead......, we analyze the transverse thermal motion of the DNA. Tension at the center of the DNA adds up to 16 pN, giving almost fully stretched DNA. This method was devised for optical mapping of DNA, specifically, DNA denaturation patterns. It may be useful also for other studies, e.g., DNA......-protein interactions, specifically, their tension dependence. Generally, wherever long strands of DNA—e.g., native DNA extracted from human cells or bacteria—must be stretched with ease for inspection, this method applies....

  15. New Molecular Knowledge Towards the Trigemino-Cardiac Reflex as a Cerebral Oxygen-Conserving Reflex

    Directory of Open Access Journals (Sweden)

    N. Sandu

    2010-01-01

    Full Text Available The trigemino-cardiac reflex (TCR represents the most powerful of the autonomous reflexes and is a subphenomenon in the group of the so-called “oxygen-conserving reflexes”. Within seconds after the initiation of such a reflex, there is a powerful and differentiated activation of the sympathetic system with subsequent elevation in regional cerebral blood flow (CBF, with no changes in the cerebral metabolic rate of oxygen (CMRO2 or in the cerebral metabolic rate of glucose (CMRglc. Such an increase in regional CBF without a change of CMRO2 or CMRglc provides the brain with oxygen rapidly and efficiently. Features of the reflex have been discovered during skull base surgery, mediating reflex protection projects via currently undefined pathways from the rostral ventrolateral medulla oblongata to the upper brainstem and/or thalamus, which finally engage a small population of neurons in the cortex. This cortical center appears to be dedicated to transduce a neuronal signal reflexively into cerebral vasodilatation and synchronization of electrocortical activity; a fact that seems to be unique among autonomous reflexes. Sympathetic excitation is mediated by cortical-spinal projection to spinal preganglionic sympathetic neurons, whereas bradycardia is mediated via projections to cardiovagal motor medullary neurons. The integrated reflex response serves to redistribute blood from viscera to the brain in response to a challenge to cerebral metabolism, but seems also to initiate a preconditioning mechanism. Previous studies showed a great variability in the human TCR response, in special to external stimuli and individual factors. The TCR gives, therefore, not only new insights into novel therapeutic options for a range of disorders characterized by neuronal death, but also into the cortical and molecular organization of the brain.

  16. EFFECTIVENESS OF PNF STRETCHING AND CYCLIC STRETCHING OF CALF TIGHTNESS ON COLLEGE GOING GIRLS

    Directory of Open Access Journals (Sweden)

    Ashlesha Sirari

    2015-06-01

    Full Text Available Background: Flexibility helps with injury prevention, the reduction of soreness following a workout, and a general sense of well-being. There are different stretching techniques and protocols for improvements in calf extensibility and flexibility. The purpose of the study was to investigate the effectiveness of two techniques i.e. CYCLIC and PNF stretching which improves calf flexibility. This study was done to find the effectiveness of calf Cyclic and PNF stretching technique to improve calf flexibility. Methods: 30 subjects with age group 21-22 years were randomly allocated to 2 groups equally. Group 1(n=15 were given CYCLIC and group 2(n=15 were given PNF stretching technique. Plantar flexion was used to measure the calf tightness which was done before and after the treatment. Treatment was given for 7 days and on the 7th day the calf tightness was again measured. Results: The mean difference of the CYCLIC is 4.6 and mean difference of PNF is 4.7 which indicate that CYCLIC and PNF both are effective to improve calf flexibility but PNF is more effective than CYCLIC to improve calf flexibility. Conclusion: The neurophysiological basis of PNF, stating that the excitatory efficient of the neuromuscular spindle or the inhibitory afferent of the Golgi tendon organ (GTO or both are responsible for the effects. During PNF stretch and isometric contraction of stretched agonists for extended period may cause activation of its neuromuscular spindle. The increase in tension created during the isometric contraction of the pre – lengthened agonist contracts concentrically. Both the fascia & the spindle of the agonist adjust to the nearly lengthened position. These impulses travel via causing post synaptic inhibition of the motor neuron to agonist increasing the tension from the GTO. These impulses can override the impulses coming from the neuromuscular spindles arousing the muscle to reflexly resist to the change in length, thus helping in lengthening

  17. Computation of inverse functions in a model of cerebellar and reflex pathways allows to control a mobile mechanical segment.

    Science.gov (United States)

    Ebadzadeh, M; Tondu, B; Darlot, C

    2005-01-01

    . These results allow to link the behavioral concepts of the equilibrium-point "lambda model" [J Motor Behav 18 (1986) 17] with anatomical and physiological features: gains of reflexes and sensori-motor reactions set the slope of the "invariant characteristic," and efferent copies set the "threshold of the stretch reflex." Thus, mathematical and physical laws account for the raison d'etre of the inhibitory nature of Purkinje cells and for the conspicuous anatomical pattern of the cerebellar pathways. These properties of these pathways allow to perform approximate inverse calculations after learning of direct functions, and insure also the coordination of voluntary and reflex motor orders.

  18. The Interrater Reliability of Subjective Assessments of the Babinski Reflex.

    Science.gov (United States)

    Dafkin, Chloe; Green, Andrew; Kerr, Samantha; Veliotes, Demetri; Olivier, Benita; McKinon, Warrick

    2016-01-01

    The Babinski reflex is a clinical diagnostic tool; however, the interrater reliability of this tool is currently greatly contested. A comparison between rater groups with objective measurements of the Babinski reflex was therefore conducted. Fifteen recorded Babinski reflexes were assessed by 12 neurologists and 12 medical students as being either pathological or nonpathological. Kinematic and electromyographic variables were collected and used to assess which aspects of the Babinski reflex predict classification. Substantial interrater agreement within the neurologist and student groups (κ = .72 and .67, respectively) was shown; however, there were some differing aspects between what neurologists and students used to assess the reflex as determined by objective kinematic measurements.

  19. Quantification of the effects of an alpha-2 adrenergic agonist on reflex properties in spinal cord injury using a system identification technique

    Directory of Open Access Journals (Sweden)

    Chen David

    2010-06-01

    Full Text Available Abstract Background Despite numerous investigations, the impact of tizanidine, an anti-spastic medication, on changes in reflex and muscle mechanical properties in spasticity remains unclear. This study was designed to help us understand the mechanisms of action of tizanidine on spasticity in spinal cord injured subjects with incomplete injury, by quantifying the effects of a single dose of tizanidine on ankle muscle intrinsic and reflex components. Methods A series of perturbations was applied to the spastic ankle joint of twenty-one spinal cord injured subjects, and the resulting torques were recorded. A parallel-cascade system identification method was used to separate intrinsic and reflex torques, and to identify the contribution of these components to dynamic ankle stiffness at different ankle positions, while subjects remained relaxed. Results Following administration of a single oral dose of Tizanidine, stretch evoked joint torque at the ankle decreased significantly (p Conclusions Our findings demonstrate that tizanidine acts to reduce reflex mechanical responses substantially, without inducing comparable changes in intrinsic muscle properties in individuals with spinal cord injury. Thus, the pre-post difference in joint mechanical properties can be attributed to reflex changes alone. From a practical standpoint, use of a single "test" dose of Tizanidine may help clinicians decide whether the drug can helpful in controlling symptoms in particular subjects.

  20. Modulation of the initial light reflex during affective picture viewing.

    Science.gov (United States)

    Henderson, Robert R; Bradley, Margaret M; Lang, Peter J

    2014-09-01

    An initial reflexive constriction of the pupil to stimulation-the light reflex-is primarily modulated by brightness, but is attenuated when participants are under threat of shock (i.e., fear-inhibited light reflex). The present study assessed whether the light reflex is similarly attenuated when viewing emotional pictures. Pupil diameter was recorded while participants viewed erotic, violent, and neutral scenes that were matched in brightness; scrambled versions identical in brightness were also presented as an additional control. Compared to viewing neutral scenes, the light reflex was reliably modulated by hedonic content, with significant attenuation both when viewing unpleasant as well as pleasant pictures. No differences in the light reflex were found among scrambled versions. Thus, emotional modulation of the initial light reflex is not confined to a context of fear and is not indicative of brightness differences when viewing pictures of natural scenes. Copyright © 2014 Society for Psychophysiological Research.

  1. The role of stretching in tendon injuries.

    Science.gov (United States)

    Witvrouw, E; Mahieu, N; Roosen, P; McNair, P

    2007-04-01

    The function of tendons can be classified into two categories: tensile force transmission, and storage and release of elastic energy during locomotion. The action of tendons in storing and releasing energy is mainly seen in sports activities with stretch-shortening cycles (SSCs). The more intense the SSC movements are (jumping-like activities), the more frequently tendon problems are observed. High SSC movements impose high loads on tendons. Consequently, tendons that frequently deal with high SSC motion require a high energy-absorbing capacity to store and release this large amount of elastic energy. As the elasticity of tendon structures is a leading factor in the amount of stored energy, prevention and rehabilitation programmes for tendon injuries should focus on increasing this tendon elasticity in athletes performing high SSC movements. Recently, it has been shown that ballistic stretching can significantly increase tendon elasticity. These findings have important clinical implications for treatment and prevention of tendon injuries.

  2. Modeling aftershocks as a stretched exponential relaxation

    Science.gov (United States)

    Mignan, A.

    2015-11-01

    The decay rate of aftershocks has been modeled as a power law since the pioneering work of Omori in the late nineteenth century. Although other expressions have been proposed in recent decades to describe the temporal behavior of aftershocks, the number of model comparisons remains limited. After reviewing the aftershock models published from the late nineteenth century until today, I solely compare the power law, pure exponential and stretched exponential expressions defined in their simplest forms. By applying statistical methods recommended recently in applied mathematics, I show that all aftershock sequences tested in three regional earthquake catalogs (Southern and Northern California, Taiwan) and with three declustering techniques (nearest-neighbor, second-order moment, window methods) follow a stretched exponential instead of a power law. These results infer that aftershocks are due to a simple relaxation process, in accordance with most other relaxation processes observed in Nature.

  3. Stretching a Semiflexible Polymer in a Tube

    Directory of Open Access Journals (Sweden)

    Runhua Li

    2016-09-01

    Full Text Available How the statistical behavior of semiflexible polymer chains may be affected by force stretching and tube confinement is a classical unsolved problem in polymer physics. Based on the Odijk deflection theory and normal mode decomposition in terms of Fourier expansion, we have derived a new compact formula for the extension of a wormlike chain of finite length strongly confined in a tube and simultaneously stretched by an external force. We have also suggested a new deflection length, which together with the force-extension relation is valid for a very extended range of the tube-diameter/persistence-length ratio comparing to the classic Odijk theory. The newly derived formula has no adjustable fitting parameters for the whole deflection regime; in contrast, the classic Odijk length needs different prefactors to fit the free energy and average extension, respectively. Brownian dynamics simulations based on the Generalized Bead-Rod (GBR model were extensively performed, which justified the theoretical predictions.

  4. How the Cloud Stretches the SOA Scope

    Directory of Open Access Journals (Sweden)

    Lakshmanan G

    2012-09-01

    Full Text Available In this article, we will describe how the enterprise serviceoriented-architecture (SOA scope is stretched with the advent of cloud computing. With the help of the case study of a fictitious global retailer, we will demonstrate the process for identifying cloud scenarios. Also, we will come across an emerging breed of distributed applications—both on-premise and in the Cloud—and discuss the integration considerations for building them.

  5. Dynamics and structure of stretched flames

    Energy Technology Data Exchange (ETDEWEB)

    Law, C.K. [Princeton Univ., NJ (United States)

    1993-12-01

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  6. Laser treatment of stretch marks: preliminary results

    Science.gov (United States)

    Longo, Leonardo; Piccinetti, A. L.; Monache, G. D.; Botta, G.; Mancini, S.

    2000-06-01

    The best treatment of these stretch mark is still unknown. Some authors proposed the treatment with flash-lamp-pumped dye laser 585 nm, with fluence over 8 J/cm2. Reviewing our experiences on no-surgical effects of lasers in the various phases of the wound healing, including the re- epithelization, we would like to apply the no-surgical laser therapy treating the stretch marks of breast, abdomen and lumbo-sacral region. The goal is to inhibit the fibrous tissue metabolism, encouraging the destruction of the collagen fibers with inflammatory mechanism, and increasing the reconstitution of the superficial dermis layers. We treated five cases of stretch marks in women 22-35 years old, since May 1999, with a cycle of applications of double lasers, 511 and 577 nm, with energy of 20 Joule for spot, respecting the maximum thermal relaxation times of the skin. We waited two weeks interval between the applications. Results obtained after five applications are very positive, and we are encouraged to continue this experimentation.

  7. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    Science.gov (United States)

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  8. The nature of suprasegmental influences on the late reflex activity in human forearm muscles.

    Science.gov (United States)

    Chequer, R S; Goodin, D S; Aminoff, M J

    1991-12-06

    The earliest component of the late EMG response (M2) to sudden stretch of an isometrically contracting muscle is influenced by suprasegmental mechanism, but whether these are tonic, phasic, or both, is uncertain. We have therefore investigated the nature of these mechanisms by varying the predictability of the direction of perturbation of forearm muscles held isometrically against a constant flexor or extensor force of 2.3 N. We found that the M2 response did not change appreciably regardless of whether the direction of perturbation was known in advance or which hand was used by the subject. These findings suggest that any tonic supraspinal influence of the M2 response is of little significance compared to the importance of phasic mechanisms and provide support for the existence of a cerebral arc subserving this reflex component.

  9. Group Ia afferents contribute to short-latency interlimb reflexes in the human biceps femoris muscle

    DEFF Research Database (Denmark)

    Stevenson, Andrew James Thomas; Kamavuako, Ernest Nlandu; Geertsen, Svend Sparre

    2017-01-01

    and velocity of the iKnee rotations. Methods 11 seated participants (mean age: 25 ± 5 years) performed a voluntary isometric knee extension with the ipsilateral leg and contralateral knee flexion to 10% of maximum voluntary contraction (MVC). A mechanical actuator (MTS-Systems Corporation) imposed i...... amplitudes (4 vs. 8°) at the same 150°/s velocity (p’s > 0.08). Conclusion Because fast conducting group Ia muscle spindle afferents are sensitive to changes in muscle stretch velocity, while group II spindle afferents are sensitive to changes in amplitude (Grey et al., JPhysiol., 2001; Matthews, Trends...... Neurosci., 1991), group Ia velocity sensitive muscle spindle afferents likely contribute to the short-latency crossed spinal reflexes in the cBF muscle following iKnee joint rotations. This supports the findings for the short-latency crossed responses in the human soleus muscle (Stubbs & Mrachacz...

  10. Reflexive regulation of CSR to promote sustainablility

    DEFF Research Database (Denmark)

    Buhmann, Karin

    climate change and environmental sustainability, and social, economic and other human rights lend human rights as part of CSR a potential for meeting some environmental and climate concerns and handling adverse side-effects. The article analyses two EU initiatives: The EU Multi-Stakeholder (MSF) on CSR...... in promoting companies’ responsibility with regard to aspects of sustainable development, such as climate impact. Keywords: Sustainable development, sustainable companies, reflexive regulation, climate change, CSR, EU law, public-private regulation, companies' self-regulation...... and the EU CSR Alliance. Focusing on human rights based in international law, it analyses the patterns of negotiation in the MSF and the background for the launch of the CSR Alliance. It shows that analysing public-private regulation of CSR from the perspective of reflexive law theory assists us...

  11. Reflexive cartography a new perspective in mapping

    CERN Document Server

    Casti, Emanuela

    2015-01-01

    Reflexive Cartography addresses the adaptation of cartography, including its digital forms (GIS, WebGIS, PPGIS), to the changing needs of society, and outlines the experimental context aimed at mapping a topological space. Using rigorous scientific analysis based on statement consistency, relevance of the proposals, and model accessibility, it charts the transition from topographical maps created by state agencies to open mapping produced by citizens. Adopting semiotic theory to uncover the complex communicative mechanisms of maps and to investigate their ability to produce their own messages and new perspectives, Reflexive Cartography outlines a shift in our way of conceptualizing maps: from a plastic metaphor of reality, as they are generally considered, to solid tools that play the role of agents, assisting citizens as they think and plan their own living place and make sense of the current world. Applies a range of technologies to theoretical perspectives on mapping to innovatively map the world's geogr...

  12. The Reflexive Principle of Sociological Theorization

    Directory of Open Access Journals (Sweden)

    R T Ubaidullayeva

    2013-12-01

    Full Text Available The article attempts to describe the reflexive principle in theory-making, which integrates the basic modern methodological paradigms and lays the foundation for the development of sociology. On the basis of the theoretical ideas of P. Bourdieu, A. Giddens and P. Ricoeur the author defines the concept of social reflexion and reveals its peculiarities in sociology as compared to reflexion in philosophy. According to the author, the fulfillment of reflexive functions in sociology is connected with the task of analyzing the complex structure of the polysemantic object, considering the specific quality of the subjects and their various trends of development. The presence of the poles — objectivity-subjectivity, rationality-irrationality, consciousness-unconsciousness etc, requires a reproduction of the dichotomies engendering them in social life and development of cognitive methods for their study in sociology.

  13. Tactile Sensing Reflexes for Advanced Prosthetic Hands

    Science.gov (United States)

    2016-10-01

    Quad Chart 37 1. INTRODUCTION: The purpose of this research is to equip a myoelectric prosthetic hand with contact detecting sensors and a...controller to perform contact detection reflex (11-13 mos.) 80% • Program controller to perform software functions for clinical studies (12-13 mos.) 60...candidates have been ordered, and are having pressure relief holes laser drilled . A custom flexible component board that holds the pressure sensor

  14. Experimental Characterization of Stretch-Bending Formability of AHSS Sheets

    Science.gov (United States)

    Kitting, Daniela; Ofenheimer, Aldo; Pauli, Heinrich; Till, Edwin T.

    2011-05-01

    Deformation conditions of combined stretching and bending are known to enhance material formability compared to forming conditions without bending (e.g. in-plane stretching). These phenomena can be observed for most conventional steel grades but is even more pronounced for Advanced High Strength Steel (AHSS) sheets. Consequently, there is an urgent need in industry to quantify the phenomena of enhanced material formability due to bending effects. In this work new stretch-bend test setups are presented which can be used in addition to the conventional Angular Stretch Bend Test to systematically investigate the influence of various stretch-bending deformation conditions on the formability of AHSS sheets.

  15. The spinal reflex cannot be perceptually separated from voluntary movements.

    Science.gov (United States)

    Ghosh, Arko; Haggard, Patrick

    2014-01-01

    Both voluntary and involuntary movements activate sensors in the muscles, skin, tendon and joints. As limb movement can result from a mixture of spinal reflexes and voluntary motor commands, the cortical centres underlying conscious proprioception might either aggregate or separate the sensory inputs generated by voluntary movements from those generated by involuntary movements such as spinal reflexes. We addressed whether healthy volunteers could perceive the contribution of a spinal reflex during movements that combined both reflexive and voluntary contributions. Volunteers reported the reflexive contribution in leg movements that were partly driven by the knee-jerk reflex induced by a patellar tendon tap and partly by voluntary motor control. In one condition, participants were instructed to kick back in response to a tendon tap. The results were compared to reflexes in a resting baseline condition without voluntary movement. In a further condition, participants were instructed to kick forwards after a tap. Volunteers reported the perceived reflex contribution by repositioning the leg to the perceived maximum displacement to which the reflex moved the leg after each tendon tap. In the resting baseline condition, the reflex was accurately perceived. We found a near-unity slope of linear regressions of perceived on actual reflexive displacement. Both the slope value and the quality of regression fit in individual volunteers were significantly reduced when volunteers were instructed to generate voluntary backward kicks as soon as they detected the tap. In the kick forward condition, kinematic analysis showed continuity of reflex and voluntary movements, but the reflex contribution could be estimated from electromyography (EMG) recording on each trial. Again, participants' judgements of reflexes showed a poor relation to reflex EMG, in contrast to the baseline condition. In sum, we show that reflexes can be accurately perceived from afferent information. However

  16. The effect of distraction strategies on pain perception and the nociceptive flexor reflex (RIII reflex).

    Science.gov (United States)

    Ruscheweyh, Ruth; Kreusch, Annette; Albers, Christoph; Sommer, Jens; Marziniak, Martin

    2011-11-01

    Distraction from pain reduces pain perception, and imaging studies have suggested that this may at least partially be mediated by activation of descending pain inhibitory systems. Here, we used the nociceptive flexor reflex (RIII reflex) to directly quantify the effects of different distraction strategies on basal spinal nociception and its temporal summation. Twenty-seven healthy subjects participated in 3 distraction tasks (mental imagery, listening to preferred music, spatial discrimination of brush stimuli) and, in a fourth task, concentrated on the painful stimulus. Results show that all 3 distraction tasks reduced pain perception, but only the brush task also reduced the RIII reflex. The concentration-on-pain task increased both pain perception and the RIII reflex. The extent of temporal summation of pain perception and the extent of temporal summation of the RIII reflex were not affected by any of the tasks. These results suggest that some, but not all, forms of pain reduction by distraction rely on descending pain inhibition. In addition, pain reduction by distraction seems to preferentially affect mechanisms of basal nociceptive transmission, not of temporal summation. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  17. Basic Gravitational Reflexes in the Larval Frog

    Science.gov (United States)

    Cochran, Stephen L.

    1996-01-01

    This investigation was designed to determine how a primitive vertebrate, the bullfrog tadpole, is able to sense and process gravitational stimuli. Because of the phylogenetic similarities of the vestibular systems in all vertebrates, the understanding of the gravitational reflexes in this relatively simple vertebrate should elucidate a skeletal framework on a elementary level, upon which the more elaborate reflexes of higher vertebrates may be constructed. The purpose of this study was to understand how the nervous system of the larval amphibian processes gravitational information. This study involved predominantly electrophysiological investigations of the isolated, alert (forebrain removed) bullfrog tadpole head. The focus of these experiments is threefold: (1) to understand from whole extraocular nerve recordings the signals sent to the eye following static gravitational tilt of the head; (2) to localize neuronal centers responsible for generating these signals through reversible pharmacological ablation of these centers; and (3) to record intracellularly from neurons within these centers in order to determine the single neuron's role in the overall processing of the center. This study has provided information on the mechanisms by which a primitive vertebrate processes gravitational reflexes.

  18. Acoustic reflex patterns in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Canale, Andrea; Albera, Roberto; Lacilla, Michelangelo; Canosa, Antonio; Albera, Andrea; Sacco, Francesca; Chiò, Adriano; Calvo, Andrea

    2017-02-01

    The aim of the study is to investigate acoustic reflex testing in amyotrophic lateral sclerosis patients. Amplitude, latency, and rise time of stapedial reflex were recorded for 500 and 1000 Hz contralateral stimulus. Statistical analysis was performed by the Wilcoxon test and the level of significance was set at 5 %. Fifty-one amyotrophic lateral sclerosis patients and ten sex- and age-matched control subjects were studied. Patients were further divided in two groups: amyotrophic lateral sclerosis-bulbar (38 cases, with bulbar signs at evaluation) and amyotrophic lateral sclerosis-spinal (13 cases, without bulbar signs at evaluation). Stapedial reflex was present in all patients. There was a statistically significant difference in the mean amplitude, latency, and rise time between the amyotrophic lateral sclerosis patients as compared with the controls. Amplitude was lower in both the amyotrophic lateral sclerosis-bulbar and the amyotrophic lateral sclerosis-spinal patients than in the controls (p amyotrophic lateral sclerosis cases with bulbar signs and, moreover, suggesting a possible subclinical involvement of the stapedial motor neuron even in amyotrophic lateral sclerosis-spinal patients. Amplitude and rise time seem to be good sensitive parameters for investigating subclinical bulbar involvement.

  19. Social orienting: reflexive versus voluntary control.

    Science.gov (United States)

    Hill, Julia L; Patel, Saumil; Gu, Xue; Seyedali, Nassim S; Bachevalier, Jocelyne; Sereno, Anne B

    2010-09-24

    Many studies have shown that the direction of gaze of a face covertly facilitates the response to a target presented in the matching direction. In this study we seek to determine whether there exist separate reflexive and voluntary forms of such covert social orienting and how they interact with each other. We measured the effect of the predictive value of a gaze cue on manual choice reaction times. When the predictive value of the gaze cue was zero, a facilitatory cueing effect was still observed which peaked at a cue onset to target onset delay (CTD) of 150ms and largely diminished beyond a CTD of 500ms. When the gaze cue was 100% predictive of the future location of the target, at CTDs greater than 200, the predictive cue resulted in a significantly greater facilitation of response than occurred with a non-predictive cue. These results suggest that given enough time (about 200ms), the social cue is interpreted and a willful or voluntary spatially-specific social cueing effect occurs. In addition, we found that a predictive cue resulted in a significant slowing of the observer's responses up to a CTD of 200ms. These findings show that, similar to non-social spatial orienting, there appear to be two forms of social orienting including a reflexive component and voluntary component. We suggest a model of social orienting in which the voluntary social orienting system modulates tonic inhibition of the reflexive social orienting system. Published by Elsevier Ltd.

  20. Clinical correlation of cervical myelopathy and the hyperactive pectoralis reflex.

    Science.gov (United States)

    Paholpak, Permsak; Jirarattanaphochai, Kitti; Sae-Jung, Surachai; Wittayapairoj, Kriangkrai

    2013-12-01

    A diagnostic study. To validate the correlation between hyperactive pectoralis reflex and the level of cervical myelopathy. The hyperactive pectoralis reflex was proposed to be present in patients with spinal cord compression at the C2-3 and/or C3-4 level. Nevertheless, in a validation study on the correlation of various hyperactive reflexes and the cervical myelopathic level, this particular reflex was not evaluated. All patients presenting with cervical myelopathy between August 2009 and June 2012 were included in this study. Each patient underwent neurological examination for cervical myelopathy focusing on the examination of pathologic reflexes, including the hyperactive pectoralis reflex. We recorded the presence or absence of these reflexes and the level of cervical myelopathy as detected on magnetic resonance imaging. We used the level of spinal cord compression-cranial to C4 of the vertebral body-as the reference level to validate a hyperactive pectoralis reflex. The study included 95 cervical myelopathy patients: 33 patients had most of their compressed cervical cord somewhere above the C4 vertebral body. The hyperactive pectoralis reflex for cervical myelopathy at this level had a respective sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 84.8%, 96.7%, 26.67, and 0.16. The high sensitivity and specificity of the hyperactive pectoralis reflex is very useful for screening and diagnosis of the cervical myelopathic level when it is above the C4 vertebral body.

  1. Does residual force enhancement increase with increasing stretch magnitudes?

    Science.gov (United States)

    Hisey, Brandon; Leonard, Tim R; Herzog, Walter

    2009-07-22

    It is generally accepted that force enhancement in skeletal muscles increases with increasing stretch magnitudes. However, this property has not been tested across supra-physiological stretch magnitudes and different muscle lengths, thus it is not known whether this is a generic property of skeletal muscle, or merely a property that holds for small stretch magnitudes within the physiological range. Six cat soleus muscles were actively stretched with magnitudes varying from 3 to 24 mm at three different parts of the force-length relationship to test the hypothesis that force enhancement increases with increasing stretch magnitude, independent of muscle length. Residual force enhancement increased consistently with stretch amplitudes on the descending limb of the force-length relationship up to a threshold value, after which it reached a plateau. Force enhancement did not increase with stretch amplitude on the ascending limb of the force-length relationship. Passive force enhancement was observed for all test conditions, and paralleled the behavior of the residual force enhancement. Force enhancement increased with stretch magnitude when stretching occurred at lengths where there was natural passive force within the muscle. These results suggest that force enhancement does not increase unconditionally with increasing stretch magnitude, as is generally accepted, and that increasing force enhancement with stretch appears to be tightly linked to that part of the force-length relationship where there is naturally occurring passive force.

  2. The Relevance of Stretch Intensity and Position: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nikos eApostolopoulos

    2015-08-01

    Full Text Available Stretching exercises to increase the range of motion (ROM of joints have been used by sports coaches and medical professionals for improving performance and rehabilitation. The ability of connective and muscular tissues to change their architecture in response to stretching is important for their proper function, repair and performance. Given the dearth of relevant data in the literature, this review examined two key elements of stretching: stretch intensity and stretch position; and their significance to ROM, delayed onset muscle soreness (DOMS, and inflammation in different populations. A search of three databases, Pub-Med, Google Scholar, and Cochrane Reviews, identified 152 articles, which were subsequently categorized into four groups; athletes (n = 24, clinical (n = 29, elderly (n = 12, and general population (n = 87. The use of different populations facilitated a wider examination of the stretching components and their effects. All 152 articles incorporated information regarding duration, frequency and stretch position, whereas only 79 referred to the intensity of stretching and 22 of these 79 studies were deemed high quality. It appears that the intensity of stretching is relatively under-researched, and the importance of body position and its influence on stretch intensity, is largely unknown. In conclusion, this review has highlighted areas for future research, including stretch intensity and position and their effect on musculo-tendinous tissue, in relation to the sensation of pain, delayed onset muscle soreness, inflammation, as well as muscle health and performance

  3. Effects of cervical self-stretching on slow vital capacity.

    Science.gov (United States)

    Han, Dongwook; Yoon, Nayoon; Jeong, Yeongran; Ha, Misook; Nam, Kunwoo

    2015-07-01

    [Purpose] This study investigated the effects of self-stretching of cervical muscles, because the accessory inspiratory muscle is considered to improve pulmonary function. [Subjects] The subjects were 30 healthy university students 19-21 years old who did not have any lung disease, respiratory dysfunction, cervical injury, or any problems upon cervical stretching. [Methods] Spirometry was used as a pulmonary function test to measure the slow vital capacity before and after stretching. The slow vital capacity of the experimental group was measured before and after cervical self-stretching. Meanwhile, the slow vital capacity of the control group, which did not perform stretching, was also measured before and after the intervention. [Results] The expiratory vital capacity, inspiratory reserve volume, and expiratory reserve volume of the experimental group increased significantly after the cervical self-stretching. [Conclusion] Self-stretching of the cervical muscle (i.e., the inspiratory accessory muscle) improves slow vital capacity.

  4. 基于"Stretching"技术的QPSO算法%QPSO Algorithm Based on Stretching Technique

    Institute of Scientific and Technical Information of China (English)

    于敏; 孙俊; 须文波; 江家宝

    2006-01-01

    基于量子行为的粒子群优化算法(QPSO)是一种随机的全局优化搜索新方法.文章系统的介绍了PSO算法、QPSO算法和"Stretching"技术.在对QPSO算法和基于"Stretching"技术的PSO算法分析的基础上,提出了基于"Stretch-ing"技术的QPSO算法.然后用标准测试函数对新算法进行了实验.实验结果表明,新算法在解的收敛性和稳定性等方面优于基于"Stretching"技术的PSO算法.

  5. Human plantarflexor stiffness to multiple single-stretch trials.

    Science.gov (United States)

    Blanpied, P; Smidt, G L

    1992-01-01

    The purpose of this investigation was to determine the influence of different stretch velocities, different rates of pre-stretch force development, and different pre-stretch muscle lengths on the intrinsic stiffness exhibited by the quasi-statically contracting active human plantarflexors during multiple single-stretch trials at 20-60% of maximum isometric contraction. Subjects were positioned prone, with the knee flexed 1.57 rad(90 degrees), shank stabilized, and foot secured in a hard plastic orthotic. Slowly increasing isometric plantarflexion force was produced until the plantarflexors were stretched by a rapid 0.2 rad (12 degrees) dorsiflexion movement. Plantarflexion forces and ankle positions were determined during these stretches as well as during resting stretches when the muscle was inactive. Resting forces were subtracted from the active trials, forces converted to torques, and stiffnesses determined for the first 62 ms of the stretch. The slope of the stiffness vs pre-stretch torque relationship averaged 4.30 +/- 0.34 Nm rad-1 Nm-1. Little difference was found between stiffness determined through the single-stretch method and the results of previous studies employing different mechanical inputs. Differences in stiffnesses with different stretching velocities were caused by computational artifact rather than by differences in intrinsic muscular reaction. Faster rates of pre-stretch force increase prior to the stretch resulted in slightly lower stiffnesses. Different pre-stretch muscle lengths apparently did not result in different stiffnesses. The shape of the torque vs displacement curve was remarkably insensitive to the planned manipulations of the testing conditions, responding in a stereotypical manner.

  6. The swallowing reflex and its significance as an airway defensive reflex

    Directory of Open Access Journals (Sweden)

    Takashi eNishino

    2013-01-01

    Full Text Available Swallowing function, in humans, is very complex. Swallowing plays, not only an important role in food digestion, but also a major role in preventing the entrance of food and/or other materials into the lower respiratory tract. To achieve this, precise coordination is necessary between breathing and swallowing since the pharynx serves as a common pathway for both respiration and digestion. The swallowing reflex consists of afferent pathways, central integration, and efferent pathways. Any defect or disorder along reflex arc can cause a potential delay or impairment in swallow function. The swallowing reflex can be modulated not only by pathological factors but also by physiological factors. Among these, timing of swallows in relation to the phase of respiration may be the most important factor that determines the occurrence of pulmonary aspiration, since phases of inspiration and the expiration-inspiration transition are the most vulnerable for pulmonary aspiration.

  7. An experimental study of artificial murine bladder reflex arc established by abdominal reflex

    Institute of Scientific and Technical Information of China (English)

    WANG Jin-wu; ZHAO Yu-wu; HOU Chun-lin; NI Wei-feng; RUI Bi-yu; GUO Shang-chun; ZHENG Xian-you; DAI Ke-rong

    2011-01-01

    Background The neurogenic bladder dysfunction caused by spinal cord injury is difficult to treat clinically. The aim of this research was to establish an artificial bladder reflex arc in rats through abdominal reflex pathway above the level of spinal cord injury, reinnervate the neurogenic bladder and restore bladder micturition.Methods The outcome was achieved by intradural microanastomosis of the right T13 ventral root to S2 ventral root with autogenous nerve grafting, leaving the right T13 dorsal root intact. Long-term function of the reflex arc was assessed from nerve electrophysiological data and intravesical pressure tests during 8 months postoperation. Horseradish peroxidase (HRP) tracing was performed to observe the effectiveness of the artificial reflex.Results Single stimulus (3 mA, 0.3 ms pulses, 20 Hz, 5-second duration) on the right T13 dorsal root resulted in evoked action potentials, raised intravesical pressures and bladder smooth muscle, compound action potential recorded from the right vesical plexus before and after the spinal cord transaction injury between L5 and S4 segmental in 12 Sprague-Dawley rats. There were HRP labelled cells in T13 ventral horn on the experimental side and in the intermediolateral nucleus on both sides of the L6-S4 segments after HRP injection. There was no HRP labelled cell in T13 ventral horn on the control side.Conclusion Using the surviving somatic reflex above the level of spinal cord injury to reconstruct the bladder autonomous reflex arc by intradural microanastomosis of ventral root with a segment of autologous nerve grafting is practical in rats and may have clinical applications for humans.

  8. Reflex receptive fields for human withdrawal reflexes elicited by non-painful and painful electrical stimulation of the foot sole.

    Science.gov (United States)

    Andersen, O K; Sonnenborg, F A; Arendt-Nielsen, L

    2001-04-01

    Human withdrawal reflex receptive fields (RRFs) were assessed for 4 different electrical stimulus intensities, ranging from below the pain threshold (PTh) to up to two times the PTh intensity (0.8x, 1.2x, 1.6x, and 2.0xPTh). Thirteen subjects participated, and the reflexes were recorded in a sitting position. The stimuli were delivered in random order to 12 positions distributed over the foot sole. Tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL), and biceps femoris (BF) reflexes were recorded. Further, knee and ankle joint angle changes were recorded. The strongest reflexes were seen in the TA compared with the other 3 muscles. Dorsi-flexion dominated distal to the talocrural joint corresponding to the TA receptive field area. An expansion of the RRF for the TA and GM was seen when increasing the stimulus intensity from 0.8xPTh to 1.2xPTh and from 1.2xPTh to 1.6xPTh, indicating a gradually increasing reflex threshold towards the border, where TA contraction is inappropriate in a withdrawal reaction. For the BF and VL, the borders of the RRF areas were not detected. By integrating the reflex size within the RRF (i.e. the reflex volume), gradually increasing reflexes for increasing stimulus intensity were seen in all 4 muscles tested, most clearly in the TA and GM. The subjective pain intensity correlated to the reflex volume for the TA, GM, and BF. In conclusion, the highest reflex sensitivity was seen in the centre of the RRF, while the stimulus intensity needed for eliciting a reflex increased towards the receptive field border. Within the RRF, stronger reflexes were evoked for increasing stimulus intensity. The limit in the size of the receptive field size for the TA and GM supports a modular withdrawal reflex organisation.

  9. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    Directory of Open Access Journals (Sweden)

    Del P. Wong

    2011-06-01

    Full Text Available This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA and change of direction (COD. Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s. Three dynamic stretching exercises of 30 s duration were then performed (90 s total. Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p < 0.001. However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (< 90 s static stretching may not have provided sufficient stimulus to elicit performance impairments

  10. Stretched horizons, quasiparticles and quasinormal modes

    CERN Document Server

    Iizuka, N; Lifschytz, G; Lowe, D A; Iizuka, Norihiro; Kabat, Daniel; Lifschytz, Gilad; Lowe, David A.

    2003-01-01

    We propose that stretched horizons can be described in terms of a gas of non-interacting quasiparticles. The quasiparticles are unstable, with a lifetime set by the imaginary part of the lowest quasinormal mode frequency. If the horizon arises from an AdS/CFT style duality the quasiparticles are also the effective low-energy degrees of freedom of the finite-temperature CFT. We analyze a large class of models including Schwarzschild black holes, non-extremal Dp-branes, the rotating BTZ black hole and de Sitter space, and we comment on degenerate horizons. The quasiparticle description makes manifest the relationship between entropy and area.

  11. Optical stretching on chip with acoustophoretic prefocusing

    DEFF Research Database (Denmark)

    Khoury Arvelo, Maria; Laub Busk, L.; Bruus, Henrik

    2012-01-01

    in the microchannel. Trapping and manipulation is demonstrated for dielectric beads. In addition, we show trapping, manipulation and stretching of red blood cells and vesicles, whereby we extract the elastic properties of these objects. Our design points towards the construction of a low-cost, high-throughput lab-on-a-chip...... prefocusing. This focusing mechanism aims for target particles to always ow in the correct height relative to the optical stretcher, and is induced by a piezo-electric ultrasound transducer attached underneath the chip and driven at a frequency leading to a vertical standing ultrasound wave...

  12. CONFORMATIONAL PROPERTIES OF STRETCHED POLYETHYLENE CHAIN

    Institute of Scientific and Technical Information of China (English)

    Lin-xi Zhang; De-lu Zhao

    2000-01-01

    When polyethylene chains are stretched, the chains are regarded as being confined in an infinite cylinder with decreasing diameter. The conformational properties of polyethylene chains confined in an infinite cylinder are investigated by using rotational isomeric state model. Using the average conformational energy and entropy and the average length, we can determine the elastic force f, or the fraction of the energy term to the total force fe/f, where fe=(б)/(б)/(б). Comparisons with experimental data are also made. The results of these microscopic calculations are discussed in terms of the macroscopic phenomena of rubber elasticity.

  13. Viscous flows stretching and shrinking of surfaces

    CERN Document Server

    Mehmood, Ahmer

    2017-01-01

    This authored monograph provides a detailed discussion of the boundary layer flow due to a moving plate. The topical focus lies on the 2- and 3-dimensional case, considering axially symmetric and unsteady flows. The author derives a criterion for the self-similar and non-similar flow, and the turbulent flow due to a stretching or shrinking sheet is also discussed. The target audience primarily comprises research experts in the field of boundary layer flow, but the book will also be beneficial for graduate students.

  14. To Stretch and Search for Better Ways

    Science.gov (United States)

    Moore, John W.

    2000-06-01

    There's a lot to do to get each issue of this Journal ready for publication, and there's a lot that can go awry during that process. We the editorial staff do our utmost to make certain that each issue is the best it can possibly be, but, of necessity, a lot of our effort is focused on solving problems, correcting errors, and avoiding pitfalls. It is not surprising that we sometimes lose sight of the bigger picture--all of the things that came out as well as or better than we hoped they would. Therefore it gives us great pleasure when a reader applauds (and thereby rewards) our efforts. One such communication inspired this editorial. I have appreciated the extra effort put forward by the staff to make the Journal really come alive. The high quality of the Journal serves as an incentive to chemical educators to stretch and search for better ways to inspire our students. I fervently hope that we do encourage you "to stretch and search for better ways", not only to inspire students but in everything you do. Stretching and searching for better ways is what life, science, chemistry, and teaching are all about, and it is a wonderfully stimulating and exciting way to approach anything and everything. Sometimes, though, one's ability to stretch is akin to that of a rubber band exposed too long to sunlight. Change becomes a threat or a burden instead of an opportunity. This often happens in one area but not others, as in the case of someone doing original research but whose lecture notes are yellow with age, or someone who experiments with new teaching approaches but neglects the latest chemical discoveries. Whatever its manifestation, failure to stretch and search for better ways is a great loss, both for the individual directly involved and for others. Fortunately there are many who continually stretch and search, often in conjunction with JCE. For example, some time ago the Chair of the Board of Publication, Jerry Bell, challenged Journal readers to become Journal

  15. Finite stretching of an annular plate.

    Science.gov (United States)

    Biricikoglu, V.; Kalnins, A.

    1971-01-01

    The problem of the finite stretching of an annular plate which is bonded to a rigid inclusion at its inner edge is considered. The material is assumed to be isotropic and incompressible with a Mooney-type constitutive law. It is shown that the inclusion of the effect of the transverse normal strain leads to a rapid variation in thickness which is confined to a narrow edge zone. The explicit solutions to the boundary layer equations, which govern the behavior of the plate near the edges, are presented.

  16. Wind effects on a stretched membrane heliostat

    Energy Technology Data Exchange (ETDEWEB)

    Bienkiewicz, B. (Colorado State Univ., Fort Collins, CO (United States). Dept. of Civil Engineering)

    1993-08-01

    Wind effects on stretched membrane heliostat were investigated in a boundary layer wind tunnel. The membrane response was measured at stow and representative operational conditions. It was found that both at the stow and operational conditions the mean response was much higher than the rms response. At stow conditions the largest response occurred near the leading edge of the membrane, while the rms response was the largest at the membrane center point. For the operational conditions, the largest mean and rms responses were found at the membrane centerpoint. The membrane response was significantly reduced by the membrane focusing induced through the internal underpressure.

  17. Muscular response to physiologic tensile stretch of the caprine c5/6 facet joint capsule: dynamic recruitment thresholds and latencies.

    Science.gov (United States)

    Azar, Nadia R; Kallakuri, Srinivasu; Chen, Chaoyang; Cavanaugh, John M

    2011-11-01

    This study examined the cervical muscle response to physiologic, high-rate (100 mm/s) tensile facet joint capsule (FJC) stretch. Six in-vivo caprine C5/6 FJC preparations were subjected to an incremental tensile loading paradigm. EMG activity was recorded from the right trapezius (TR) and multifidus (MF) muscle groups at the C5 and C6 levels; and from the sternomastoid (SM) and longus colli (LC) muscle groups bilaterally at the C5/6 level; during FJC stretch. Capsule load during the displacement applications was recorded via a miniature load cell, and 3D capsule strains (based on stereoimaging of an array of markers on the capsule surface) were reconstructed using finite element methods. EMG traces from each muscle were examined for onset of muscular activity. Capsule strains and loads at the time of EMG onset were recorded for each muscle, as was the time from the onset of FJC stretch to the onset of muscle activity. All muscles were responsive to physiologic high-rate FJC stretch. The deep muscles (MF and LC) were recruited at significantly smaller capsule loads and onset latencies than the superficial muscles (TR and SM). MF activation strain was significantly smaller than LC and TR activation strains. These data were also compared to previously published low-rate data. MF was the first muscle group to be recruited regardless of the activation criterion under consideration (i.e. strain, load, or latency) or the rate of FJC stretch. LC recruitment occurred significantly sooner under high-rate vs. low-rate FJC stretch. The results of this study provide further evidence of extensive ligamento-muscular reflex pathways between the FJC and the cervical musculature, which are responsive to both low-rate and high-rate FJC stretch. These data add to our knowledge of the dynamic response of paraspinal muscles relative to facet joint motion and provide a unique contribution to enhance the precision of computer-simulated impacts.

  18. Assessment of Hyperactive Reflexes in Patients with Spinal Cord Injury

    Science.gov (United States)

    Yang, Chung-Yong

    2015-01-01

    Hyperactive reflexes are commonly observed in patients with spinal cord injury (SCI) but there is a lack of convenient and quantitative characterizations. Patellar tendon reflexes were examined in nine SCI patients and ten healthy control subjects by tapping the tendon using a hand-held instrumented hammer at various knee flexion angles, and the tapping force, quadriceps EMG, and knee extension torque were measured to characterize patellar tendon reflexes quantitatively in terms of the tendon reflex gain (G tr), contraction rate (R c), and reflex loop time delay (t d). It was found that there are significant increases in G tr and R c and decrease in t d in patients with spinal cord injury as compared to the controls (P reflex excitability and muscle contraction dynamics. With proper simplifications, it can potentially be used for quantitative diagnosis and outcome evaluations of hyperreflexia in clinical settings. PMID:25654084

  19. The parallel programming of voluntary and reflexive saccades.

    Science.gov (United States)

    Walker, Robin; McSorley, Eugene

    2006-06-01

    A novel two-step paradigm was used to investigate the parallel programming of consecutive, stimulus-elicited ('reflexive') and endogenous ('voluntary') saccades. The mean latency of voluntary saccades, made following the first reflexive saccades in two-step conditions, was significantly reduced compared to that of voluntary saccades made in the single-step control trials. The latency of the first reflexive saccades was modulated by the requirement to make a second saccade: first saccade latency increased when a second voluntary saccade was required in the opposite direction to the first saccade, and decreased when a second saccade was required in the same direction as the first reflexive saccade. A second experiment confirmed the basic effect and also showed that a second reflexive saccade may be programmed in parallel with a first voluntary saccade. The results support the view that voluntary and reflexive saccades can be programmed in parallel on a common motor map.

  20. Sympathetic reflex control of blood flow in human peripheral tissues

    DEFF Research Database (Denmark)

    Henriksen, O

    1991-01-01

    Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human ...... to collision of normodromically and antidromically conducted impulses in efferent sympathetic vasoconstrictor fibers. The evidence obtained suggests that sympathetic vasoconstrictor reflexes to postural changes are complex and highly differentiated....

  1. A syntactic and lexical approach to French reflexive verbs

    Directory of Open Access Journals (Sweden)

    Corina Petersilka

    2012-01-01

    Full Text Available This Construction grammar approach to French refl exive verbs describes the formal and semantic constraints at work in the different refl exive constructions, points out at their different branches of inheritance and shows cases of fusion with other argument structures. The article suggests a family tree of French reflexive constructions which appear to be derived from different transitive constructions. It also deals with how the reflexive argument structure modifies the semantics of the transitive verb used in reflexive construction.

  2. Polarized actin structural dynamics in response to cyclic uniaxial stretch

    Science.gov (United States)

    Huang, Lawrence; Helmke, Brian P.

    2014-01-01

    Endothelial cell (EC) alignment to directional flow or stretch supports anti-inflammatory functions, but mechanisms controlling polarized structural adaptation in response to physical cues remain unclear. This study aimed to determine whether factors associated with early actin edge ruffling implicated in cell polarization are prerequisite for stress fiber (SF) reorientation in response to cyclic uniaxial stretch. Time-lapse analysis of EGFP-actin in confluent ECs showed that onset of either cyclic uniaxial or equibiaxial stretch caused a non-directional increase in edge ruffling. Edge activity was concentrated in a direction perpendicular to the stretch axis after 60 min, consistent with the direction of SF alignment. Rho-kinase inhibition caused reorientation of both stretch-induced edge ruffling and SF alignment parallel to the stretch axis. Arp2/3 inhibition attenuated stretch-induced cell elongation and disrupted polarized edge dynamics and microtubule organizing center reorientation, but it had no effect on the extent of SF reorientation. Disrupting localization of p21-activated kinase (PAK) did not prevent stretch-induced SF reorientation, suggesting that this Rac effector is not critical in regulating stretch-induced cytoskeletal remodeling. Overall, these results suggest that directional edge ruffling is not a primary mechanism that guides SF reorientation in response to stretch; the two events are coincident but not causal. PMID:25821527

  3. Sympathetic reflex control of blood flow in human peripheral tissues

    DEFF Research Database (Denmark)

    Henriksen, O

    1991-01-01

    Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human...... sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno...

  4. Rounded stretched exponential for time relaxation functions.

    Science.gov (United States)

    Powles, J G; Heyes, D M; Rickayzen, G; Evans, W A B

    2009-12-01

    A rounded stretched exponential function is introduced, C(t)=exp{(tau(0)/tau(E))(beta)[1-(1+(t/tau(0))(2))(beta/2)]}, where t is time, and tau(0) and tau(E) are two relaxation times. This expression can be used to represent the relaxation function of many real dynamical processes, as at long times, t>tau(0), the function converges to a stretched exponential with normalizing relaxation time, tau(E), yet its expansion is even or symmetric in time, which is a statistical mechanical requirement. This expression fits well the shear stress relaxation function for model soft soft-sphere fluids near coexistence, with tau(E)Cole-Cole plots for dielectric and shear stress relaxation (both the modulus and viscosity forms). It is shown that both the dielectric spectra and dynamic shear modulus imaginary parts approach the real axis with a slope equal to 0 at high frequency, whereas the dynamic viscosity has an infinite slope in the same limit. This indicates that inertial effects at high frequency are best discerned in the modulus rather than the viscosity Cole-Cole plot. As a consequence of the even expansion in time of the shear stress relaxation function, the value of the storage modulus derived from it at very high frequency exceeds that in the infinite frequency limit (i.e., G(infinity)).

  5. Curved Piezoelectric Actuators for Stretching Optical Fibers

    Science.gov (United States)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  6. The legacy of care as reflexive learning.

    Science.gov (United States)

    García, Marta Rodríguez; Moya, Jose Luis Medina

    2016-06-14

    to analyze whether the tutor's use of reflexive strategies encourages the students to reflect. The goal is to discover what type of strategies can help to achieve this and how tutors and students behave in the practical context. a qualitative and ethnographic focus was adopted. Twenty-seven students and 15 tutors from three health centers participated. The latter had received specific training on reflexive clinical tutoring. The analysis was developed through constant comparisons of the categories. the results demonstrate that the tutors' use of reflexive strategies such as didactic questioning, didactic empathy and pedagogical silence contributes to encourage the students' reflection and significant learning. reflexive practice is key to tutors' training and students' learning. analisar se o uso de estratégias reflexivas por parte da tutora de estágio clínico estimula a reflexão nos estudantes. A intenção é descobrir qual tipo de estratégias podem ajudar a fazê-lo e como as tutoras e os estudantes se comportam no contexto prático. foi adotado um enfoque qualitativo de cunho etnográfico em que participaram 27 estudantes e 15 tutores de três centros de saúde que haviam recebido formação específica sobre tutoria clínica reflexiva. A análise foi realizada por meio de comparações constantes das categorias. os resultados demonstram que o uso de estratégias reflexivas como a interrogação didática, a empatia didática e o silêncio pedagógico por parte das tutoras, contribui para fomentar a reflexão do estudante e sua aprendizagem significativa. a prática reflexiva é a chave para a formação dos tutores e para a aprendizagem dos estudantes. analizar si el uso de estrategias reflexivas por parte de la tutora de prácticas clínicas fomenta la reflexión en los estudiantes. Se trata de conocer qué tipo de estrategias pueden ayudar a hacerlo y cómo se comportan tutoras y estudiantes en el contexto práctico. se ha utilizado un enfoque

  7. Lower esophageal sphincter relaxation reflex kinetics: effects of peristaltic reflexes and maturation in human premature neonates.

    Science.gov (United States)

    Pena, Eneysis M; Parks, Vanessa N; Peng, Juan; Fernandez, Soledad A; Di Lorenzo, Carlo; Shaker, Reza; Jadcherla, Sudarshan R

    2010-12-01

    We defined the sensory-motor characteristics of the lower esophageal sphincter relaxation (LESR) (stimulus threshold volume, response onset, and relaxation period, relaxation magnitude, nadir) during maturation in human neonates. We hypothesized that LESR kinetics differs during maturation and with peristaltic reflex type. Basal and adaptive esophageal motility testing was performed (N = 20 premature neonates) at 34.7 and 39.1 wk (time 1 and time 2). Effects of midesophageal provocation with graded stimuli (N = 1,267 stimuli, air and liquids) on LESR kinetics during esophagodeglutition response (EDR) and secondary peristalsis (SP) were analyzed by mixed models. Frequency of LESR with basal primary peristalsis were different during maturation (P = 0.03). During adaptive responses with maturation, 1) the frequencies of peristaltic reflexes and LESR were similar; 2) liquid stimuli resulted in a shorter LESR response latency and LESR nadir and greater LESR magnitude (all P reflexes at both times (vs. none, P reflex, and postnatal maturation. Maturation modulates an increased recruitment of inhibitory pathways that favor LESR.

  8. An Enabling Framework for Reflexive Learning: Experiential Learning and Reflexivity in Contemporary Modernity

    Science.gov (United States)

    Dyke, Martin

    2009-01-01

    The paper presents an enabling framework for experiential learning that connects with reflexive modernity. This framework places an emphasis on learning with others and on the role of theory, practice and reflection. A sociological argument is constructed for an alternative framework for experiential learning that derives from social theory. It is…

  9. Methodological Reflexivity: Towards Evolving Methodological Frameworks through Critical and Reflexive Deliberations

    Science.gov (United States)

    Raven, Glenda

    2006-01-01

    In this article, the author argues for a central and critical role for "reflexivity in research" with the aim of developing and strengthening not only everyone's understanding of what everyone does in environmental education research, but also how, and why everyone does it. In a narrative account of methodological issues that occurred…

  10. Reflexivity and vulnerability in collaborative knowledge production

    DEFF Research Database (Denmark)

    Jakobsen, Helle Nordentoft; Olesen, Birgitte Ravn

    in the interaction between the peers. This can, for instance be observed in the participants’ tone of voice and body-language. In other words, these moments can be seen as naturally occurring ‘breaching incidents’ in an apparently fruitful learning environment (Have, 2004). As such, they have potential to expose...... the normativity,, of the ways in which roles and relationships between the peers and researchers unfold. In both instances, the ambition was to create a reflexive learning environment in which peers co-produce new knowledge on how to communicate with patients and relatives; however, we conclude that the opposite...

  11. Effects of stretching the scalene muscles on slow vital capacity

    Science.gov (United States)

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-01-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study’s methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC. PMID:27390425

  12. Effects of stretching the scalene muscles on slow vital capacity.

    Science.gov (United States)

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-06-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study's methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC.

  13. Effects of stretching the scalene muscles on slow vital capacity

    OpenAIRE

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-01-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study’s methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 ti...

  14. Effects of cervical self-stretching on slow vital capacity

    OpenAIRE

    Han, Dongwook; Yoon, Nayoon; Jeong, Yeongran; Ha, Misook; Nam, Kunwoo

    2015-01-01

    [Purpose] This study investigated the effects of self-stretching of cervical muscles, because the accessory inspiratory muscle is considered to improve pulmonary function. [Subjects] The subjects were 30 healthy university students 19–21 years old who did not have any lung disease, respiratory dysfunction, cervical injury, or any problems upon cervical stretching. [Methods] Spirometry was used as a pulmonary function test to measure the slow vital capacity before and after stretching. The slo...

  15. Acute effect of different stretching methods on isometric muscle strength

    OpenAIRE

    Gabriel Vasconcellos de Lima Costa e Silva; Anderson Luiz Bezerra da Silveira; Fabrízio Di Masi; Cláudio Melibeu Bentes; Maria do Socorro Cirilo de Sousa; Jefferson da Silva Novaes

    2014-01-01

    http://dx.doi.org/10.4025/actascihealthsci.v36i1.15581 This study investigated the acute effect of static stretching methods (SS) and proprioceptive neuromuscular facilitation (PNF) on the static muscle strength (SMS). Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a) hand grip without stretching; b) hand grip preceded by static stretching of wrist flexor...

  16. The Process Analysis of the Roller Stretching for Wool Slenderization

    Institute of Scientific and Technical Information of China (English)

    刘洪玲; 于伟东; 章悦庭

    2003-01-01

    A theoretical estimation for the multiple-drawing has been derived under the consideration of fiber length distribution for the wool fiber stretching system. The functions of the roller drawing system and the parameters in stretching process have also been analyzed. The theoretical algorithms have been verified by the experimental results and can be used for the estimation of fiber length and its distribution after the stretching.

  17. Effects of three different stretching techniques on vertical jumping performance.

    Science.gov (United States)

    Kirmizigil, Berkiye; Ozcaldiran, Bahtiyar; Colakoglu, Muzaffer

    2014-05-01

    The aim of this study was to evaluate 3 different flexibility techniques: (a) ballistic stretching (BS), (b) proprioceptive neuromuscular facilitation stretching (PNF) + BS, and (c) PNF + static stretching (SS) on vertical jump (VJ) performance and to determine the most appropriate stretching method during warm-up period before explosive force disciplines. One hundred voluntary male athletes participated in this study. All subjects performed aerobic warm-up (5-minute jog) followed by BS (5 seconds for each stretching exercise), PNF + BS (PNF performed followed by 5 seconds of BS), and PNF + SS (PNF performed followed by 30 seconds of SS) treatment protocol, respectively in the same day. Each stretching treatment was applied for 4 sets bilaterally. In all stretching treatments, lumbar extensor, gluteus maximus, and hamstring muscles were stretched with a single stretching exercise. After a 2-minute brief rest period, participants performed 3 trials of VJ test followed by one of the treatment protocols. Vertical jump performance was evaluated by countermovement jump (CMJ). Participants were divided into 3 groups according to their flexibility and prejump performances after warm-up. For each individual group and the whole group, after all treatments, differences in CMJ values were obtained (p ≤ 0.05). Ballistic stretching increased the VJ performance in the groups with low and average flexibility, poor prejumping performance, and also in the whole group (p ≤ 0.05). Proprioceptive neuromuscular facilitation stretching + BS affected VJ performance in the group of participants with high flexibility (p ≤ 0.05). Proprioceptive neuromuscular facilitation + SS decreased VJ performance in groups of participants with high flexibility, moderate, and high prejumping performance and in whole group (p ≤ 0.05). Ballistic stretching method increased VJ height, therefore seems to be more suitable than PNF + SS and PNF + BS before events that rely on explosive power as a part

  18. High-Pressure Balloon-Assisted Stretching of the Coracohumeral Ligament to Determine the Optimal Stretching Positions: A Cadaveric Study.

    Science.gov (United States)

    Baek, Sora; Lee, Kyu Jin; Kim, Keewon; Han, Seung-Ho; Lee, U-Young; Lee, Kun-Jai; Chung, Sun Gun

    2016-10-01

    The coracohumeral ligament (CHL) is a thick capsular structure and markedly thickened when affected by adhesive capsulitis. Therapeutic stretching is the most commonly applied treatment for adhesive capsulitis, but optimal stretching postures for maximal therapeutic effects on the CHL have not been fully investigated. To investigate the most effective stretching direction for the CHL by measuring the stretching intensity in 5 different directions and to determine whether the stretching intervention resulted in loosening of the ligament by comparing the changes of CHL tightness before and after stretching. Biomechanical cadaver study. Academic institution cadaver laboratory. Nine fresh frozen cadaveric shoulders. A high-pressure balloon catheter inserted under the CHL and intraballoon pressure was measured, to evaluate CHL tightness without ligament damage as well as to augment and monitor stretching intensity. To find the optimal stretching direction, the glenohumeral joint was stretched from the neutral position into 5 directions sequentially under pressure-monitoring: flexion, extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD] directions. CHL tightness was determined by a surrogate parameter, the additional pressure created by the overlying CHL. The pressure increase (ΔPstr) by a specific directional stretch was considered as the stretching intensity. ΔPstr by the 5 directions were mean (standard deviation) values of 0.03 ± 0.07 atm, 0.87 ± 1.31 atm, 1.13 ± 1.36 atm, 1.49 ± 1.32 atm, and 2.10 ± 1.70 atm, respectively, revealing the highest ΔPstr by the EX+ER+AD stretch (P stretching manipulation. EX+ER+AD of the glenohumeral joint resulted in the greatest increase in balloon pressure, implying that it could be the most effective stretching direction. A series of stretching manipulations assisted with an underlying pressure balloon were capable of decreasing CHL tightness. With further development and modification, high

  19. 600 Volt Stretched Lens Array for Solar Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ENTECH, Auburn, NASA, and others have recently developed a new space photovoltaic array called the Stretched Lens Array (SLA), offering unprecedented performance...

  20. Activity-Dependent Increase in Neurotrophic Factors Is Associated with an Enhanced Modulation of Spinal Reflexes after Spinal Cord Injury

    Science.gov (United States)

    Côté, Marie-Pascale; Azzam, Gregory A.; Lemay, Michel A.; Zhukareva, Victoria

    2011-01-01

    Abstract Activity-based therapies such as passive bicycling and step-training on a treadmill contribute to motor recovery after spinal cord injury (SCI), leading to a greater number of steps performed, improved gait kinematics, recovery of phase-dependent modulation of spinal reflexes, and prevention of decrease in muscle mass. Both tasks consist of alternating movements that rhythmically stretch and shorten hindlimb muscles. However, the paralyzed hindlimbs are passively moved by a motorized apparatus during bike-training, whereas locomotor movements during step-training are generated by spinal networks triggered by afferent feedback. Our objective was to compare the task-dependent effect of bike- and step-training after SCI on physiological measures of spinal cord plasticity in relation to changes in levels of neurotrophic factors. Thirty adult female Sprague-Dawley rats underwent complete spinal transection at a low thoracic level (T12). The rats were assigned to one of three groups: bike-training, step-training, or no training. The exercise regimen consisted of 15 min/d, 5 days/week, for 4 weeks, beginning 5 days after SCI. During a terminal experiment, H-reflexes were recorded from interosseus foot muscles following stimulation of the tibial nerve at 0.3, 5, or 10 Hz. The animals were sacrificed and the spinal cords were harvested for Western blot analysis of the expression of neurotrophic factors in the lumbar spinal cord. We provide evidence that bike- and step-training significantly increase the levels of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and NT-4 in the lumbar enlargement of SCI rats, whereas only step-training increased glial cell-derived neurotrophic factor (GDNF) levels. An increase in neurotrophic factor protein levels that positively correlated with the recovery of H-reflex frequency-dependent depression suggests a role for neurotrophic factors in reflex normalization. PMID:21083432

  1. Reflexivity and adjustment strategies at the interfaces

    Directory of Open Access Journals (Sweden)

    Ismael Teomiro

    2011-10-01

    Full Text Available I argue in this work that Reinhart & Reuland’s (1993 conditions A and B hold for Spanish. I provide evidence supporting the hypothesis that this language makes use of both SE and SELF-anaphors. Inherent reflexive verbs undergo an internal argument reduction operation in the lexicon. However, the syntax always requires two arguments. Therefore certain clitics, which are SE-anaphors, are inserted in these derivations. This is a last-resort mechanism that makes an adjustment between the valence of the lexical entry of the verb and the requirements of the syntax in order for the derivation to converge at the C-I interface. These clitics are syntactic arguments. Nevertheless, they are not interpreted as semantic arguments since they violate the double chain condition, which forces nominal elements to share both a tense and thematic features with the verb and the tense heads. Non- inherent reflexive verbs require the presence of a SELF-anaphor, which is formed out of a SE-anaphor along with a protector SELF element. Therefore, both syntactic elements are interpreted as two distinguishable semantic elements at C-I despite the fact that there is binding between them both. The interpretation of both syntactic elements as just one semantic element is a pragmatic epiphenomenon.

  2. The Self-Reflexivity of Social Action

    Directory of Open Access Journals (Sweden)

    Bogdan POPOVENIUC

    2015-12-01

    Full Text Available The most puzzling and striking feature of Social Theory lies in the impossibility to control its leaning toward self-fulfilling statements. In Sociology, the epistemic explanation become part of explained world and the Theory is at risk to become either futile or subjective along with the dialectic evolution of social understanding. As major mature sciences, it has solid instruments and methods for acquiring useful knowledge, self-regulatory rules for assuring the accuracy of its affirmations and errors refutation. More than any other sciences, it achieved the level of meta-theoretical thinking about its own practice and sets up its limits and expertise. However this is not enough. The understanding brought by sociological the most evolved concept of reflexivity is overwhelmed complexity of social reality, because it fails to cover the self-reference supposed by itself. The Scientific discourse of third person should be transcended toward the level of dialectical co-constructed consciousness-reality awareness, that the subjective “I”, is the condition of possibility for objective knowledge (of Science, which, in turn, represents the categorical conditions of possibility for (self-understanding. A self-reflexive level of understanding instead, would illuminate many concealed suppositions, conundrums and inconsistencies of social discourse and reasoning. This enhancement is also required to put the present uncontrolled collective intelligent development of Mankind on a safety and desirable path.

  3. Effect of guaifenesin on cough reflex sensitivity.

    Science.gov (United States)

    Dicpinigaitis, Peter V; Gayle, Yvonne E

    2003-12-01

    Guaifenesin, a commonly used agent for the treatment of cough, is termed an expectorant since it is believed to alleviate cough discomfort by increasing sputum volume and decreasing its viscosity, thereby promoting effective cough. Despite its common usage, relatively few studies, yielding contrasting results, have been performed to investigate the action and efficacy of guaifenesin. To evaluate the effect of guaifenesin on cough reflex sensitivity. Randomized, double-blind, placebo-controlled trial. Academic medical center. Fourteen subjects with acute viral upper respiratory tract infection (URI) and 14 healthy volunteers. On 2 separate days, subjects underwent capsaicin cough challenge 1 to 2 h after receiving a single, 400-mg dose (capsules) of guaifenesin or matched placebo. The concentration of capsaicin inducing five or more coughs (C(5)) was determined. Among subjects with URI, mean (+/- SEM) log C(5) after guaifenesin and placebo were 0.92 +/- 0.17 and 0.66 +/- 0.14, respectively (p = 0.028). No effect on cough sensitivity was observed in healthy volunteers. Our results demonstrate that guaifenesin inhibits cough reflex sensitivity in subjects with URI, whose cough receptors are transiently hypersensitive, but not in healthy volunteers. Possible mechanisms include a central antitussive effect, or a peripheral effect by increased sputum volume serving as a barrier shielding cough receptors within the respiratory epithelium from the tussive stimulus.

  4. Cough reflex sensitization from esophagus and nose.

    Science.gov (United States)

    Hennel, Michal; Brozmanova, Mariana; Kollarik, Marian

    2015-12-01

    The diseases of the esophagus and nose are among the major factors contributing to chronic cough although their role in different patient populations is debated. Studies in animal models and in humans show that afferent C-fiber activators applied on esophageal or nasal mucosa do not initiate cough, but enhance cough induced by inhaled irritants. These results are consistent with the hypothesis that activation of esophageal and nasal C-fibers contribute to cough reflex hypersensitivity observed in chronic cough patients with gastroesophageal reflux disease (GERD) and chronic rhinitis, respectively. The afferent nerves mediating cough sensitization from the esophagus are probably the neural crest-derived vagal jugular C-fibers. In addition to their responsiveness to high concentration of acid typical for gastroesophageal reflux (pH cough sensitization are less understood. Increased cough reflex sensitivity was also reported in many patients with GERD or rhinitis who do not complain of cough indicating that additional endogenous or exogenous factors may be required to develop chronic coughing in these diseases.

  5. Somatoautonomic reflexes in acupuncture therapy: A review.

    Science.gov (United States)

    Uchida, Sae; Kagitani, Fusako; Sato-Suzuki, Ikuko

    2017-03-01

    Oriental therapies such as acupuncture, moxibustion, or Anma, have been used to treat visceral disorders since ancient times. In each of these therapies, stimulation of the skin or underlying muscles leads to excitation of afferent nerves. The sensory information is carried to the central nervous system, where it is transferred to autonomic efferents, thus affecting visceral functions. This neuronal pathway, known as the "somatoautonomic reflex", has been systematically studied by Sato and his colleagues for over a half century. Nearly all their studies were conducted in anesthetized animals, whereas human patients are conscious. Responses in patients or the events following therapeutic somatic stimulation may differ from those observed in anesthetized animals. In fact, it is increasingly apparent that the responses in patients and animals are not always coincident, and the differences have been difficult for clinicians to reconcile. We review the mechanism of the "somatoautonomic reflex" as described in anesthetized animals and then discuss how it can be applied clinically. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Metabolic syndrome and the hepatorenal reflex

    Directory of Open Access Journals (Sweden)

    Michael D Wider

    2016-01-01

    Full Text Available Insufficient hepatic O 2 in animal and human studies has been shown to elicit a hepatorenal reflex in response to increased hepatic adenosine, resulting in stimulation of renal as well as muscle sympathetic nerve activity and activating the renin angiotensin system. Low hepatic ATP, hyperuricemia, and hepatic lipid accumulation reported in metabolic syndrome (MetS patients may reflect insufficient hepatic O 2 delivery, potentially accounting for the sympathetic overdrive associated with MetS. This theoretical concept is supported by experimental results in animals fed a high fructose diet to induce MetS. Hepatic fructose metabolism rapidly consumes ATP resulting in increased adenosine production and hyperuricemia as well as elevated renin release and sympathetic activity. This review makes the case for the hepatorenal reflex causing sympathetic overdrive and metabolic syndrome in response to exaggerated splanchnic oxygen consumption from excessive eating. This is strongly reinforced by the fact that MetS is cured in a matter of days in a significant percentage of patients by diet, bariatric surgery, or endoluminal sleeve, all of which would decrease splanchnic oxygen demand by limiting nutrient contact with the mucosa and reducing the nutrient load due to the loss of appetite or dietary restriction.

  7. LABOR GYMNASTICS: STRETCHING EXERCISE X FLEXIONAMENT

    Directory of Open Access Journals (Sweden)

    Jacqueline Amorin Anchieta Borges da Silva, Isabel Cristina Taranto e Fernanda Piasecki

    2006-12-01

    Full Text Available Nowadays, there are many opportunities for the society to live a healthful and long life. At the same time, never people was so sedentary and without harmony. Without a healthy body and with “an occupied mind” the human loses exactly what more it needs: the disposal to produce, to coexist and to live a good life. In this context, the present research aimed to revise some terms related to labor gymnastics, which is focused in the prevention of risks related to hours of working and in the reduction of muscular tension levels that may be originated during a day of work. Thus, the present study will make a differentiation between the use of stretching and flexionament during labor gymnastic sessions.

  8. Modeling Aftershocks as a Stretched Exponential Relaxation

    CERN Document Server

    Mignan, Arnaud

    2015-01-01

    The decay rate of aftershocks has been modeled as a power law since the pioneering work of Omori in the late nineteenth century. Considered the second most fundamental empirical law after the Gutenberg-Richter relationship, the power law paradigm has rarely been challenged by the seismological community. By taking a view of aftershock research not biased by prior conceptions of Omori power law decay and by applying statistical methods recommended in applied mathematics, I show that all aftershock sequences tested in three regional earthquake catalogs (Southern and Northern California, Taiwan) and with three declustering techniques (nearest-neighbor, second-order moment, window methods) follow a stretched exponential instead of a power law. These results infer that aftershocks are due to a simpler relaxation process than originally thought, in accordance with most other relaxation processes observed in Nature.

  9. EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    Meena .V

    2016-10-01

    Full Text Available Background: Osteoarthritis (OA is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hold relax stretching versus static stretching on pain and flexibility of hamstrings following moist heat in knee osteoarthritis participants. Determining the effects of PNF Hold relax stretching versus Static stretching along with moist heat on pain and hamstring flexibility by VAS and Active knee extension range of motion in knee osteoarthritis individuals. Methods: 30 subjects with symptoms of knee osteoarthritis were randomly distributed into 2 groups 15 in each group. PNF Hold relax stretching along with moist heat is compared to Static stretching along with moist heat. Pain was measured by Visual Analogue Scale (VAS and hamstring flexibility by Active knee Extension Range of Motion (AKEROM by universal goniometer. Measurements are taken pre and post intervention. Results: The results indicated PNF Hold relax stretching along with moist heat showed a statistically significant improvement in pain (p<0.05 and improvement in hamstring flexibility (p<0.05 when compared to Static stretching along with moist heat. Conclusion: Subjects with PNF Hold relax stretching along with moist heat showed significant improvement in pain reduction and improving hamstring flexibility than Static stretching along with moist heat.

  10. The Role of Transformational Leadership in Enhancing Team Reflexivity

    NARCIS (Netherlands)

    M.C. Schippers (Michaéla); D.N. den Hartog (Deanne); P.L. Koopman (Paul); D.L. van Knippenberg (Daan)

    2007-01-01

    textabstractTeam reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to

  11. Bourdieu and Science Studies: Toward a Reflexive Sociology

    Science.gov (United States)

    Hess, David J.

    2011-01-01

    Two of Bourdieu's fundamental contributions to science studies--the reflexive analysis of the social and human sciences and the concept of an intellectual field--are used to frame a reflexive study of the history and social studies of science and technology as an intellectual field in the United States. The universe of large, Ph.D.-granting…

  12. The role of transformational leadership in enhancing team reflexivity

    NARCIS (Netherlands)

    Schippers, M.C.; den Hartog, D.N.; Koopman, P.L.; van Knippenberg, D.

    2008-01-01

    Team reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to develop the

  13. [Value of blink reflex studies in neurosurgical problems].

    Science.gov (United States)

    Jamjoom, Z; Nahser, H C; Nau, H E

    1983-09-01

    Blinking reflex studies were done in neurosurgical patients with processes in the posterior fossa and idiopathic trigeminal neuralgia. Alterations were found in space occupying, ischemic, and traumatic lesions of the trigemino-facial system. The analysis of the components of the blinking reflex can give hints to the site of the lesion and also to the prognosis of the underlying process.

  14. (Re)constructing Reflexivity: A Relational Constructionist Approach

    NARCIS (Netherlands)

    Hosking, D.M.; Pluut, B.

    2010-01-01

    This article distinguishes three discourses of reflexivity in relation to human inquiry. One of these arises from a post-modern, relational constructionist perspective which radically re-conceptualizes reflexivity: (a) as a local and co-constructed process oriented towards the question (b) how are w

  15. Reflexivity in Teams: A Review and New Perspectives.

    Science.gov (United States)

    Konradt, Udo; Otte, Kai-Philip; Schippers, Michaéla C; Steenfatt, Corinna

    2016-01-01

    Team reflexivity posits that the extent to which teams reflect upon and adapt their functioning is positively related to team performance. While remarkable progress has been made to provide evidence of this relationship, the underlying framework is missing elements of current theoretical streams for analyzing and describing teamwork, leaving the diversity of effects of team reflexivity often untouched. In this article, we present an update for this framework, by reviewing previous research on reflexivity, addressing gaps in the literature, and revising the original model by integrating feedback and dynamic team effectiveness frameworks for describing temporal developments of reflexivity. We furthermore propose a new dimensional structure for reflexivity, relying on prior work conceptualizing teams as information-processing systems that learn and advance through social-cognitive elements. Our model is therefore not only suitable for explaining the diverse set of relationships between team reflexivity on outcomes, but also provides valuable directions for viewing reflexivity as process that takes place during both transition and action phases of teamwork. We conclude with implications for managers, identify limitations, and propose an agenda for further research into this area. This article contributes an extended perspective relevant for further theory development and for effectively managing reflexivity in teams.

  16. Iris Pigmentation and Fractionated Reaction and Reflex Time.

    Science.gov (United States)

    Hale, Bruce D.; And Others

    Behavioral measures, fractionated reaction and reflex times by means of electromyography, were used to determine if the eye color differences are found in the central or peripheral regions of the nervous system. The purpose of this research was to determine the truth of the hypothesis that dark-eyed individuals have faster reflex and reaction time…

  17. [The development of I. P. Pavlov's conditioned reflex theory].

    Science.gov (United States)

    Kim, O J

    1992-01-01

    This paper deals with the theory of Ivan Petrovich Pavlov (1849-1936), a Russian physiologist who presented for the first time the systematic theory of the function of the brain that controls the whole behavior of animals, i.e. higher nervous activity through experimental studies. This paper, principally based on Lectures on Conditioned Reflexes (1928), investigates the development of conditioned reflex theory from its beginning by dividing it into three periods. First, during the period from 1898 to 1906, the fundamental concept of conditioned reflex was established and the study of conditioned reflex became an independent discipline. From 1907 to 1916, the second period, Pavlov theorized on higher nervous activity on the basis of extensive data from his laboratory experiments of conditioned reflex. And Pavlov complemented conditioned reflex theory, during the third period from 1916 to 1928, and extended the boundaries of it through applications of conditioned reflex theory to psychopathology and typology. The study contributes to the understanding that conditioned reflex theory was historically developed, and not presented as a complete form from the beginning, and that Pavlov intended to study the higher nervous activity through the method of neurophysiology.

  18. (Re)constructing Reflexivity: A Relational Constructionist Approach

    NARCIS (Netherlands)

    Hosking, D.M.; Pluut, B.

    2010-01-01

    This article distinguishes three discourses of reflexivity in relation to human inquiry. One of these arises from a post-modern, relational constructionist perspective which radically re-conceptualizes reflexivity: (a) as a local and co-constructed process oriented towards the question (b) how are

  19. Ultimate concerns in late modernity: Archer, Bourdieu and reflexivity.

    Science.gov (United States)

    Farrugia, David; Woodman, Dan

    2015-12-01

    Through a critique of Margaret Archer's theory of reflexivity, this paper explores the theoretical contribution of a Bourdieusian sociology of the subject for understanding social change. Archer's theory of reflexivity holds that conscious 'internal conversations' are the motor of society, central both to human subjectivity and to the 'reflexive imperative' of late modernity. This is established through critiques of Bourdieu, who is held to erase creativity and meaningful personal investments from subjectivity, and late modernity is depicted as a time when a 'situational logic of opportunity' renders embodied dispositions and the reproduction of symbolic advantages obsolete. Maintaining Archer's focus on 'ultimate concerns' in a context of social change, this paper argues that her theory of reflexivity is established through a narrow misreading and rejection of Bourdieu's work, which ultimately creates problems for her own approach. Archer's rejection of any pre-reflexive dimensions to subjectivity and social action leaves her unable to sociologically explain the genesis of 'ultimate concerns', and creates an empirically dubious narrative of the consequences of social change. Through a focus on Archer's concept of 'fractured reflexivity', the paper explores the theoretical necessity of habitus and illusio for understanding the social changes that Archer is grappling with. In late modernity, reflexivity is valorized just as the conditions for its successful operation are increasingly foreclosed, creating 'fractured reflexivity' emblematic of the complex contemporary interaction between habitus, illusio, and accelerating social change. © London School of Economics and Political Science 2015.

  20. The role of transformational leadership in enhancing team reflexivity

    NARCIS (Netherlands)

    Schippers, M.C.; den Hartog, D.N.; Koopman, P.L.; van Knippenberg, D.

    2008-01-01

    Team reflexivity, or the extent to which teams reflect upon and modify their functioning, has been identified as a key factor in the effectiveness of work teams. As yet, however, little is known about the factors that play a role in enhancing team reflexivity, and it is thus important to develop

  1. Reflex sympathetic dystrophy: Early treatment and psychological aspects

    NARCIS (Netherlands)

    Geertzen, J.H.B.; De Bruijn, H.; De Bruijn-Kofman, A.T.; Arendzen, J.H.

    1994-01-01

    We report the results of two prospective studies of early treatment and psychological aspects in a series of 26 patients with sympathetic reflex dystrophy of the hand in which treatment was started within 3 months after diagnosis. Ismelin blocks is an often used therapy in sympathetic reflex dystrop

  2. The feasibility of reflexive control in transfemoral prostheses

    NARCIS (Netherlands)

    Wentink, E.C.; Rietman, J.S.; Veltink, P.H.

    2009-01-01

    The feasibility of reflexive control in transfemoral prosthesis is assessed using a model of the lower extremity. The artificial triggering of reflexes, the processing of the central nervous system, the EMG detection and the control input to the prosthetic knee all take time. A model was used to ass

  3. The stretch-shortening cycle : a model to study naturally occurring neuromuscular fatigue.

    Science.gov (United States)

    Nicol, Caroline; Avela, Janne; Komi, Paavo V

    2006-01-01

    Neuromuscular fatigue has traditionally been examined using isolated forms of either isometric, concentric or eccentric actions. However, none of these actions are naturally occurring in human (or animal) ground locomotion. The basic muscle function is defined as the stretch-shortening cycle (SSC), where the preactivated muscle is first stretched (eccentric action) and then followed by the shortening (concentric) action. As the SSC taxes the skeletal muscles very strongly mechanically, its influence on the reflex activation becomes apparent and very different from the isolated forms of muscle actions mentioned above. The ground contact phases of running, jumping and hopping etc. are examples of the SSC for leg extensor muscles; similar phases can also be found for the upper-body activities. Consequently, it is normal and expected that the fatigue phenomena should be explored during SSC activities. The fatigue responses of repeated SSC actions are very versatile and complex because the fatigue does not depend only on the metabolic loading, which is reportedly different among muscle actions. The complexity of SSC fatigue is well reflected by the recovery patterns of many neuromechanical parameters. The basic pattern of SSC fatigue response (e.g. when using the complete exhaustion model of hopping or jumping) is the bimodality showing an immediate reduction in performance during exercise, quick recovery within 1-2 hours, followed by a secondary reduction, which may often show the lowest values on the second day post-exercise when the symptoms of muscle soreness/damage are also greatest. The full recovery may take 4-8 days depending on the parameter and on the severity of exercise. Each subject may have their own time-dependent bimodality curve. Based on the reviewed literature, it is recommended that the fatigue protocol is 'completely' exhaustive to reduce the important influence of inter-subject variability in the fatigue responses. The bimodality concept is

  4. Human intersegmental reflexes from intercostal afferents to scalene muscles.

    Science.gov (United States)

    McBain, Rachel A; Taylor, Janet L; Gorman, Robert B; Gandevia, Simon C; Butler, Jane E

    2016-10-01

    What is the central question of this study? The aim was to determine whether specific reflex connections operate between intercostal afferents and the scalene muscles in humans, and whether these connections operate after a clinically complete cervical spinal cord injury. What is the main finding and its importance? This is the first description of a short-latency inhibitory reflex connection between intercostal afferents from intercostal spaces to the scalene muscles in able-bodied participants. We suggest that this reflex is mediated by large-diameter afferents. This intercostal-to-scalene inhibitory reflex is absent after cervical spinal cord injury and may provide a way to monitor the progress of the injury. Short-latency intersegmental reflexes have been described for various respiratory muscles in animals. In humans, however, only short-latency reflex responses to phrenic nerve stimulation have been described. Here, we examined the reflex connections between intercostal afferents and scalene muscles in humans. Surface EMG recordings were made from scalene muscles bilaterally, in seven able-bodied participants and seven participants with motor- and sensory-complete cervical spinal cord injury (median 32 years postinjury, range 5 months to 44 years). We recorded the reflex responses produced by stimulation of the eighth or tenth left intercostal nerve. A short-latency (∼38 ms) inhibitory reflex was evident in able-bodied participants, in ipsilateral and contralateral scalene muscles. This bilateral intersegmental inhibitory reflex occurred in 46% of recordings at low stimulus intensities (at three times motor threshold). It was more frequent (in 75-85% of recordings) at higher stimulus intensities (six and nine times motor threshold), but onset latency (38 ± 9 ms, mean ± SD) and the size of inhibition (23 ± 10%) did not change with stimulus intensity. The reflex was absent in all participants with spinal cord injury. As the intercostal

  5. EFFICACY OF MODIFIED PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING WITH CRYOTHERAPY OVER MANUAL PASSIVE STRETCHING WITH CRYOTHERAPY ON HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    Shamik Bhattacharjee

    2016-04-01

    Full Text Available Background: Healthy individuals, to ease and accomplish their activities of daily living they need flexible body without any tightness in the muscles, particularly those used for a definite function. Cooling soft tissues in a lengthened position after stretching has been shown to promote more lasting increases in soft tissue length and minimize post stretch muscle soreness. There are less documented studies which compared modified proprioceptive neuromuscular facilitation (PNF stretch over passive manual stretch with cold application commonly after the interventions. Methods: Thirty high school going healthy students were divided into two groups- Group I received Passive Manual stretching (n=15 and Group II received modified PNF stretching (n=15 and both groups received cold application after the interventions for 10 minutes commonly for 5 days. ROM was taken on day 1, day 5 and day 7. Results: After day 7, Group II with Modified PNF stretching along with cold application showed a significant increase in range of motion tested with active knee extension test (AKET. Conclusion: Modified PNF stretching is considered to be the effective intervention in increasing and maintaining ROM in AKET over passive manual stretching with cold applications commonly after the interventions.

  6. Soleus H-reflex excitability during pedaling post-stroke

    DEFF Research Database (Denmark)

    Schindler-Ivens, Sheila; Brown, David A.; Lewis, Gwyn N.

    2008-01-01

    A major contributor to impaired locomotion post-stroke is abnormal phasing of paretic muscle activity, but the mechanisms remain unclear. Previous studies have shown that, in the paretic limb of people post-stroke, Group Ia reflexes are abnormally elevated and fail to decrease in amplitude during...... the pedaling cycle. H-reflexes were large during extension and small during flexion. Reduced H-reflex modulation post-stroke was associated with the level of neuromuscular impairment as indicated by Fugl-Meyer score. However, regardless of impairment level, stroke subjects displayed H-reflex suppression during...... the flexion phase of pedaling. After correcting for the level of background muscle activity, H-reflexes were found to be larger in paretic as compared to NI individuals, regardless of the phase of the pedaling cycle. We conclude that Group Ia afferent transmission is enhanced in the paretic SO of people post-stroke...

  7. Voluntary Control of the Near Reflex: A Case Report

    Directory of Open Access Journals (Sweden)

    Serpil Akar

    2014-03-01

    Full Text Available Spasm of the near reflex is a rare disorder that involves intermittent and variable episodes of esotropia, pseudomyopia, and pupillary myosis. It is usually functional in origin and is seen mainly in young patients. Treatment options for spasm of the near reflex have had variable success. In instances where the etiology of spasm of the near reflex was suspected to be hysteria, psychotherapy has proven beneficial. We report the case of an 11-year-old girl who had functional spasm of the near reflex. The symptoms persisted for two years. Symptomatic relief was achieved by cycloplegia and spectacle correction (added plus lenses at near. The patient also underwent psychological counseling. In our case, the functional spasm of the near reflex spontaneously resolved after 2 years. (Turk J Ophthalmol 2014; 44: 161-3

  8. Effects of stretching on upper-body muscular performance.

    Science.gov (United States)

    Torres, Earlando M; Kraemer, William J; Vingren, Jakob L; Volek, Jeff S; Hatfield, Disa L; Spiering, Barry A; Ho, Jen Yu; Fragala, Maren S; Thomas, Gwendolyn A; Anderson, Jeffrey M; Häkkinen, Keijo; Maresh, Carl M

    2008-07-01

    The purpose of this investigation was to examine the influence of upper-body static stretching and dynamic stretching on upper-body muscular performance. Eleven healthy men, who were National Collegiate Athletic Association Division I track and field athletes (age, 19.6 +/- 1.7 years; body mass, 93.7 +/- 13.8 kg; height, 183.6 +/- 4.6 cm; bench press 1 repetition maximum [1RM], 106.2 +/- 23.0 kg), participated in this study. Over 4 sessions, subjects participated in 4 different stretching protocols (i.e., no stretching, static stretching, dynamic stretching, and combined static and dynamic stretching) in a balanced randomized order followed by 4 tests: 30% of 1 RM bench throw, isometric bench press, overhead medicine ball throw, and lateral medicine ball throw. Depending on the exercise, test peak power (Pmax), peak force (Fmax), peak acceleration (Amax), peak velocity (Vmax), and peak displacement (Dmax) were measured. There were no differences among stretch trials for Pmax, Fmax, Amax, Vmax, or Dmax for the bench throw or for Fmax for the isometric bench press. For the overhead medicine ball throw, there were no differences among stretch trials for Vmax or Dmax. For the lateral medicine ball throw, there was no difference in Vmax among stretch trials; however, Dmax was significantly larger (p static and dynamic condition compared to the static-only condition. In general, there was no short-term effect of stretching on upper-body muscular performance in young adult male athletes, regardless of stretch mode, potentially due to the amount of rest used after stretching before the performances. Since throwing performance was largely unaffected by static or dynamic upper-body stretching, athletes competing in the field events could perform upper-body stretching, if enough time were allowed before the performance. However, prior studies on lower-body musculature have demonstrated dramatic negative effects on speed and power. Therefore, it is recommended that a dynamic

  9. Reflex control of human jaw muscles.

    Science.gov (United States)

    Türker, Kemal S

    2002-01-01

    The aim of this review is to discuss what is known about the reflex control of the human masticatory system and to propose a method for standardized investigation. Literature regarding the current knowledge of activation of jaw muscles, receptors involved in the feedback control, and reflex pathways is discussed. The reflexes are discussed under the headings of the stimulation conditions. This was deliberately done to remind the reader that under each stimulation condition, several receptor systems are activated, and that it is not yet possible to stimulate only one afferent system in isolation in human mastication experiments. To achieve a method for uniform investigation, we need to set a method for stimulation of the afferent pathway under study with minimal simultaneous activation of other receptor systems. This stimulation should also be done in an efficient and reproducible way. To substantiate our conviction to standardize the stimulus type and parameters, we discuss the advantages and disadvantages of mechanical and electrical stimuli. For mechanical stimulus to be delivered in a reproducible way, the following precautions are suggested: The stimulus delivery system (often a probe attached to a vibrator) should be brought into secure contact with the area of stimulation. To minimize the slack between the probe, the area to be stimulated should be taken up by the application of pre-load, and the delivered force should be recorded in series. Electrical stimulus has advantages in that it can be delivered in a reproducible way, though its physiological relevance can be questioned. It is also necessary to standardize the method for recording and analyzing the responses of the motoneurons to the stimulation. For that, a new technique is introduced, and its advantages over the currently used methods are discussed. The new method can illustrate the synaptic potential that is induced in the motoneurons without the errors that are unavoidable in the current

  10. Chaperones in Polyglutamine Aggregation : Beyond the Q-Stretch

    NARCIS (Netherlands)

    Kuiper, E. F. E.; de Mattos, Eduardo P.; Jardim, Laura B.; Kampinga, Harm H.; Bergink, Steven

    2017-01-01

    Expanded polyglutamine (polyQ) stretches in at least nine unrelated proteins lead to inherited neuronal dysfunction and degeneration. The expansion size in all diseases correlates with age at onset (AO) of disease and with polyQ protein aggregation, indicating that the expanded polyQ stretch is the

  11. Does Postexercise Static Stretching Alleviate Delayed Muscle Soreness?

    Science.gov (United States)

    Buroker, Katherine C.; Schwane, James A.

    1989-01-01

    Because many experts recommend stretching after exercise to relieve muscle soreness, 23 subjects performed a 30-minute step test to induce delayed muscle soreness. There was neither temporary relief of pain immediately after stretching nor a reduction in pain during the 3-day postexercise period. (Author/SM)

  12. Acute nerve stretch and the compound motor action potential

    Directory of Open Access Journals (Sweden)

    Wolfe Jacob

    2011-08-01

    Full Text Available Abstract In this paper, the acute changes in the compound motor action potential (CMAP during mechanical stretch were studied in hamster sciatic nerve and compared to the changes that occur during compression. In response to stretch, the nerve physically broke when a mean force of 331 gm (3.3 N was applied while the CMAP disappeared at an average stretch force of 73 gm (0.73 N. There were 5 primary measures of the CMAP used to describe the changes during the experiment: the normalized peak to peak amplitude, the normalized area under the curve (AUC, the normalized duration, the normalized velocity and the normalized velocity corrected for the additional path length the impulses travel when the nerve is stretched. Each of these measures was shown to contain information not available in the others. During stretch, the earliest change is a reduction in conduction velocity followed at higher stretch forces by declines in the amplitude of the CMAP. This is associated with the appearance of spontaneous EMG activity. With stretch forces Multiple means of predicting when a change in the CMAP suggests a significant stretch are discussed and it is clear that a multifactorial approach using both velocity and amplitude parameters is important. In the case of pure compression, it is only the amplitude of the CMAP that is critical in predicting which changes in the CMAP are associated with significant compression.

  13. Academic strangeness as uncomfortable reflexivity and academic reflexivity as uncomfortable strangeness in higher education

    DEFF Research Database (Denmark)

    Fristrup, Tine; Tulinius, Charlotte; Hølge-Hazelton, Bibi

    2015-01-01

    strangeness among several of the students, but also among ourselves as teachers and facilitators. We have been inspired by the work done by Ruth Behar (1996) on becoming a vulnerable observer and the work done by Pranee Liamputtong (2006) on researching the vulnerable. Both approaches involve a critique....... The paper briefly describes the strategies used to plan, deliver and evaluate the course, but the main emphasis is on the learning taking place as a consequence of working within this area and using these strategies in the educational setting. Having participated in and studied academic and peer supervision...... for the course, as teachers, was to create ‘an academic zone of comfort’ at the course, something we had been deprived of ourselves as young researchers. Our insistence on continuous reflexivity regarding the uncomfortable in order to develop academic reflexivity among the students created uncomfortable academic...

  14. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    Science.gov (United States)

    Gouw, Simone; de Wijer, Anton; Creugers, Nico Hj; Kalaykova, Stanimira I

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.

  15. Stretching and injury prevention in football: current perspectives.

    Science.gov (United States)

    Stojanovic, Marko D; Ostojic, Sergej M

    2011-04-01

    Stretching exercises are regularly recommended as a part of football-training sessions and in preparation for competition. There is little sound empirical evidence, however, to substantiate the role of stretching exercises and consequently increased flexibility on injury prevention in football. Furthermore, in the last decade or so, fundamental research has shed some light on the biomechanical adaptation of the muscle-tendon unit following different stretching protocols, improving knowledge about the topic and enabling better understanding of the stretching-injury relationship. The purpose of this review is to examine the literature on the role of stretching and/or increased flexibility on injury prevention in football, with presented results analyzed in the context of the up-to-date basic science research evidence.

  16. Acute effect of different stretching methods on isometric muscle strength

    Directory of Open Access Journals (Sweden)

    Gabriel Vasconcellos de Lima Costa e Silva

    2014-03-01

    This study investigated the acute effect of static stretching methods (SS and proprioceptive neuromuscular facilitation (PNF on the static muscle strength (SMS. Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a hand grip without stretching; b hand grip preceded by static stretching of wrist flexors muscles; c hand grip preceded by PNF stretching of wrist flexors muscles. The Shapiro-Wilk test verified the normality of data, and a one-way ANOVA with repeated measures, followed by Tukey’s post hoc test, evaluated the differences between the groups. The significance was set at p 0.05. In conclusion, both stretching methods had caused negative effects on isometric strength, reducing its levels.

  17. Linear and nonlinear buckling analysis of a locally stretched plate

    Energy Technology Data Exchange (ETDEWEB)

    Kilardj, Madina; Ikhenzzen, Ghania [University of Sciences and Technology Houari Boumediene (U.S.T.H.B), Bab Ezzouar, Algiers (Algeria); Merssager, Tanguy; Kanit, Toufik [Laboratoire de Mecanique de Lille Universite Lille 1, Cite ScientifiqueVilleneuve d' Ascq cedex (France)

    2016-08-15

    Uniformly stretched thin plates do not buckle unless they are in special boundary conditions. However, buckling commonly occurs around discontinuities, such as cracks, cuts, narrow slits, holes, and different openings, of such plates. This study aims to show that buckling can also occur in thin plates that contain no defect or singularity when the stretching is local. This specific stability problem is analyzed with the finite element method. A brief literature review on stretched plates is presented. Linear and nonlinear buckling stress analyses are conducted for a partially stretched rectangular plate, and various load cases are considered to investigate the influence of the partial loading expanse on the critical tensile buckling load. Results are summarized in iso-stress areas, tables and graphs. Local stretching on one end of the plate induces buckling in the thin plate even without geometrical imperfection.

  18. Reflexive regulation of CSR to promote sustainability

    DEFF Research Database (Denmark)

    Buhmann, Karin

    2011-01-01

    climate change and environmental sustainability, and social, economic and other human rights lend human rights as part of CSR a potential for meeting some environmental and climate concerns and handling adverse side-effects. The article analyses two EU initiatives: The EU Multi-Stakeholder (MSF) on CSR......This article discusses Corporate Social Responsibility (CSR) from the perspective of governmental regulation as a measure to promote public policy interests through public-private regulation intended to influence firms’ self-regulation. Presenting a ‘government case’ for CSR, the connection between...... and the EU CSR Alliance. Focusing on human rights based in international law, it analyses the patterns of negotiation in the MSF and the background for the launch of the CSR Alliance. It shows that analysing public-private regulation of CSR from the perspective of reflexive law theory assists us...

  19. Reflexive regulation of CSR to promote sustainablility

    DEFF Research Database (Denmark)

    Buhmann, Karin

    climate change and environmental sustainability, and social, economic and other human rights lend human rights as part of CSR a potential for meeting some environmental and climate concerns and handling adverse side-effects. The article analyses two EU initiatives: The EU Multi-Stakeholder (MSF) on CSR...... in promoting companies’ responsibility with regard to aspects of sustainable development, such as climate impact. Keywords: Sustainable development, sustainable companies, reflexive regulation, climate change, CSR, EU law, public-private regulation, companies' self-regulation......This article discusses Corporate Social Responsibility (CSR) from the perspective of governmental regulation as a measure to promote public policy interests through public-private regulation intended to influence firms’ self-regulation. Presenting a ‘government case’ for CSR, the connection between...

  20. Cultural reflexivity in health research and practice.

    Science.gov (United States)

    Aronowitz, Robert; Deener, Andrew; Keene, Danya; Schnittker, Jason; Tach, Laura

    2015-07-01

    Recent public health movements have invoked cultural change to improve health and reduce health disparities. We argue that these cultural discourses have sometimes justified and maintained health inequalities when those with power and authority designated their own social practices as legitimate and healthy while labeling the practices of marginalized groups as illegitimate or unhealthy. This "misrecognition," which creates seemingly objective knowledge without understanding historical and social conditions, sustains unequal power dynamics and obscures the fact that what is deemed legitimate and healthy can be temporally, geographically, and socially relative. We use examples from research across multiple disciplines to illustrate the potential consequences of cultural misrecognition, highlight instances in which culture was invoked in ways that overcame misrecognition, and discuss how cultural reflexivity can be used to improve health research and practice.

  1. The Chinchilla's vestibulo-ocular reflex

    Science.gov (United States)

    Merwin, W. H., Jr.; Wall, Conrad, III; Tomko, D. L.

    1989-01-01

    The horizontal vestibulo-ocular reflex (VOR) was measured and characterized in seven adult chinchillas using 0.01 to 1.0 Hz angular velocity sinusoids. Gains were less than compensatory, and were variable from day to day, but phases were highly repeatable both within and between animals. The best fitting transfer function to the average data of all animals had a dominant time constant of 7.5 sec, and an adaptation operator with a time constant of 24.0 sec. There were certain nonlinearities in the horizontal VOR of this animal, and it was difficult to elicit a robust optokinetic response. Results are discussed in relation to similar measurements in other species.

  2. Is there a hierarchy of survival reflexes?

    Science.gov (United States)

    Macphail, Kieran

    2013-10-01

    A hierarchy of survival reflexes for prioritising assessment and treatment in patients with pain of insidious onset is hypothesised. The hierarchy asserts that some systems are more vital than others and that the central nervous system (CNS) prioritises systems based on their significance to survival. The hypothesis suggests that dysfunction in more important systems will cause compensation in less important systems. This paper presents studies examining these effects for each system, arguing that each section of the hierarchy may have effects on other systems within the hierarchy. This concept is untested empirically, highly speculative and substantial research is required to validate the suggested hierarchical prioritisation by the CNS. Nonetheless, the hierarchy does provide a theoretical framework to use to exclude contributing systems in patients with pain of insidious onset. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The Disappearing Audience and Reflexive Visibility

    Directory of Open Access Journals (Sweden)

    Katerina Girginova

    2016-08-01

    Full Text Available Contrary to popular opinion and some academic writing that celebrates the renewed visibility of new media audiences, this essay argues that they are increasingly going into retreat. To understand how new media audiences “disappear” from view of one another, I borrow from Brighenti’s typology of visibility and develop the idea of “reflexive visibility.” The latter describes the ability to socially orient ourselves in a digital environment through the textual and contextual cues of others—an activity that is of utmost importance not only to researchers wishing to “see” various audiences but also for audiences writ large, wishing to know themselves.

  4. Conditioning the middle ear reflex at sensation levels below reflex threshold: air jet and electrical stimulation.

    Science.gov (United States)

    McDaniel-Bacon, L; Fulton, R T; Laskowski, R P

    1980-01-01

    An ABAB functional analysis, conditioning and generalization, design was used in 3 experiments (2 were formal studies and 1 was empirical in nature) to investigate the conditionability of the middle ear reflex. The conditioned stimuli were subreflex threshold pure tones of various frequencies and intensities. The unconditioned stimulus (UCS) was an auricular air jet to the contralateral ear in the first experiment and cutaneous electrical stimulation to the ipsolateral, probe ear in the last 2 experiments. Reflexes were monitored by an otoadmittance meter, storage oscilloscope, and strip chart recorder. In the first experiment (air jet UCS), no subjects met the conditioning criterion within the maximum presentation of 400 paired trials, despite pilot evidence which indicated conditioning was feasible. In the second experiment (electrical stimulation UCS), 2 subjects met conditioning criterion; however, only one subject reconditioned and demonstrated partial generalization to other conditioned stimuli. In the third experiment (electrical stimulation UCS), one of 3 subjects who had previously been unconditionable with the air jet UCS met conditioning and reconditioning criterion and demonstrated partial generalization. Results indicate that the middle ear reflex can be conditioned to be elicited by subreflex threshold pure tones, however, results are limited.

  5. Somatosensory imprinting in spinal reflex modules.

    Science.gov (United States)

    Schouenborg, Jens

    2003-05-01

    Understanding how sensory information is used by motor systems for motor commands requires detailed knowledge about how the body shape and biomechanics are represented in the motor circuits. We have used the withdrawal reflex system as a model for studies of sensorimotor transformation. This system has a modular organisation in the adult. Each module performs a detailed and functionally adapted sensorimotor transformation related to the withdrawal efficacy of its output muscle(s). The weight distribution of the cutaneous input to a module is determined by the pattern of withdrawal efficacy of the muscle. Recently, we found that the somatotopic organisation and weight of the cutaneous input to the dorsal horn of the lower lumbar cord is related to this modular organisation. The dorsal horn in the lower lumbar cord thus appears to be organised in a column-like fashion, where each column performs a basic sensorimotor transformation related to the movement caused by a single muscle and the body shape. Since the withdrawal reflex system encodes error signals to the cerebellum through some of the spino-olivo cerebellar pathways, the modular concept is, in fact, a key to understanding sensory processing in higher order motor systems as well. Developmental studies indicate that each module is a self-organising circuitry that uses sensory feedback on muscle contractions to adjust its synaptic organisation. Furthermore, these studies suggest that the spontaneous movements during development, by providing structured sensory information related to movement pattern of single muscles and body shape, are instrumental in shaping the sensorimotor transformation in the spinal cord. These findings and their implications for the understanding of higher motor functions and their clinical aspects will be discussed.

  6. Pre-exercise stretching does not impact upon running economy.

    Science.gov (United States)

    Hayes, Philip R; Walker, Adrian

    2007-11-01

    Pre-exercise stretching has been widely reported to reduce performance in tasks requiring maximal or near-maximal force or torque. The purpose of this study was to compare the effects of 3 different pre-exercise stretching routines on running economy. Seven competitive male middle and long-distance runners (mean +/- SD) age: 32.5 +/- 7.7 years; height: 175.0 +/- 8.8 cm; mass: 67.8 +/- 8.6 kg; V(.-)O2max: 66.8 +/- 7.0 ml x kg(-1) x min(-1)) volunteered to participate in this study. Each participant completed 4 different pre-exercise conditions: (a) a control condition, (b) static stretching, (c) progressive static stretching, and (d) dynamic stretching. Each stretching routine consisted of 2 x 30-second stretches for each of 5 exercises. Dependent variables measured were sit and reach test before and after each pre-exercise routine, running economy (ml x kg(-1) x km(-1)), and steady-state oxygen uptake (ml x kg(-1) x min(-1)), which were measured during the final 3 minutes of a 10-minute run below lactate threshold. All 3 stretching routines resulted in an increase in the range of movement (p = 0.008). There was no change in either running economy (p = 0.915) or steady-state V(.-)O2 (p = 0.943). The lack of change in running economy was most likely because it was assessed after a period of submaximal running, which may have masked any effects from the stretching protocols. Previously reported reductions in performance have been attributed to reduced motor unit activation, presumably IIX. In this study, these motor units were likely not to have been recruited; this may explain the unimpaired performance. This study suggests that pre-exercise stretching has no impact upon running economy or submaximal exercise oxygen cost.

  7. Acute effects of different stretching durations on passive torque, mobility, and isometric muscle force.

    Science.gov (United States)

    Matsuo, Shingo; Suzuki, Shigeyuki; Iwata, Masahiro; Banno, Yasuhiro; Asai, Yuji; Tsuchida, Wakako; Inoue, Takayuki

    2013-12-01

    Static stretching is widely applied in various disciplines. However, the acute effects of different durations of stretching are unclear. Therefore, this study was designed to investigate the acute effects of different stretching durations on muscle function and flexibility, and provide an insight into the optimal duration of static stretching. This randomized crossover trial included 24 healthy students (17 men and 7 women) who stretched their right hamstrings for durations of 20, 60, 180, and 300 seconds in a random order. The following outcomes were assessed using an isokinetic dynamometer as markers of lower-limb function and flexibility: static passive torque (SPT), dynamic passive torque (DPT), stiffness, straight leg raise (SLR), and isometric muscle force. Static passive torque was significantly decreased after all stretching durations (p stretching compared with that after 20-second stretching, and stiffness decreased significantly after 180- and 300-second stretching (p stretching (p stretching durations (p stretching than after 20-second stretching and higher after 300-second stretching than after 60-second stretching (p stretching durations (p stretching is associated with a decrease in SPT but an increase in SLR. Over 180 seconds of stretching was required to decrease DPT and stiffness, but isometric muscle force decreased regardless of the stretching duration. In conclusion, these results indicate that longer durations of stretching are needed to provide better flexibility.

  8. Randomized Controlled Trial Comparing Orthosis Augmented by Either Stretching or Stretching and Strengthening for Stage II Tibialis Posterior Tendon Dysfunction.

    Science.gov (United States)

    Houck, Jeff; Neville, Christopher; Tome, Josh; Flemister, Adolph

    2015-09-01

    The value of strengthening and stretching exercises combined with orthosis treatment in a home-based program has not been evaluated. The purpose of this study was to compare the effects of augmenting orthosis treatment with either stretching or a combination of stretching and strengthening in participants with stage II tibialis posterior tendon dysfunction (TPTD). Participants included 39 patients with stage II TPTD who were recruited from a medical center and then randomly assigned to a strengthening or stretching treatment group. Excluding 3 dropouts, there were 19 participants in the strengthening group and 17 in the stretching group. The stretching treatment consisted of a prefabricated orthosis used in conjunction with stretching exercises. The strengthening treatment consisted of a prefabricated orthosis used in conjunction with the stretching and strengthening exercises. The main outcome measures were self-report (ie, Foot Function Index and Short Musculoskeletal Function Assessment) and isometric deep posterior compartment strength. Two-way analysis of variance was used to test for differences between groups at 6 and 12 weeks after starting the exercise programs. Both groups significantly improved in pain and function over the 12-week trial period. The self-report measures showed minimal differences between the treatment groups. There were no differences in isometric deep posterior compartment strength. A moderate-intensity, home-based exercise program was minimally effective in augmenting orthosis wear alone in participants with stage II TPTD. Level I, prospective randomized study. © The Author(s) 2015.

  9. Modification of cutaneous reflexes during visually guided walking.

    Science.gov (United States)

    Ruff, Casey R; Miller, Andreas B; Delva, Mona L; Lajoie, Kim; Marigold, Daniel S

    2014-01-01

    Although it has become apparent that cutaneous reflexes can be adjusted based on the phase and context of the locomotor task, it is not clear to what extent these reflexes are regulated when locomotion is modified under visual guidance. To address this, we compared the amplitude of cutaneous reflexes while subjects performed walking tasks that required precise foot placement. In one experiment, subjects walked overground and across a horizontal ladder with narrow raised rungs. In another experiment, subjects walked and stepped onto a series of flat targets, which required different levels of precision (large vs. narrow targets). The superficial peroneal or tibial nerve was electrically stimulated in multiple phases of the gait cycle in each condition and experiment. Reflexes between 50 and 120 ms poststimulation were sorted into 10 equal phase bins, and the amplitudes were then averaged. In each experiment, differences in cutaneous reflexes between conditions occurred predominantly during swing phase when preparation for precise foot placement was necessary. For instance, large excitatory cutaneous reflexes in ipsilateral tibialis anterior were present in the ladder condition and when stepping on narrow targets compared with inhibitory responses in the other conditions, regardless of the nerve stimulated. In the ladder experiments, additional effects of walking condition were evident during stance phase when subjects had to balance on the narrow ladder rungs and may be related to threat and/or the unstable foot-surface interaction. Taken together, these results suggest that cutaneous reflexes are modified when visual feedback regarding the terrain is critical for successful walking.

  10. Avian reflex and electroencephalogram responses in different states of consciousness.

    Science.gov (United States)

    Sandercock, Dale A; Auckburally, Adam; Flaherty, Derek; Sandilands, Victoria; McKeegan, Dorothy E F

    2014-06-22

    Defining states of clinical consciousness in animals is important in veterinary anaesthesia and in studies of euthanasia and welfare assessment at slaughter. The aim of this study was to validate readily observable reflex responses in relation to different conscious states, as confirmed by EEG analysis, in two species of birds under laboratory conditions (35-week-old layer hens (n=12) and 11-week-old turkeys (n=10)). We evaluated clinical reflexes and characterised electroencephalograph (EEG) activity (as a measure of brain function) using spectral analyses in four different clinical states of consciousness: conscious (fully awake), semi-conscious (sedated), unconscious-optimal (general anaesthesia), unconscious-sub optimal (deep hypnotic state), as well as assessment immediately following euthanasia. Jaw or neck muscle tone was the most reliable reflex measure distinguishing between conscious and unconscious states. Pupillary reflex was consistently observed until respiratory arrest. Nictitating membrane reflex persisted for a short time (reflex is a conservative measure of death in poultry. Using spectral analyses of the EEG waveforms it was possible to readily distinguish between the different states of clinical consciousness. In all cases, when birds progressed from a conscious to unconscious state; total spectral power (PTOT) significantly increased, whereas median (F50) and spectral edge (F95) frequencies significantly decreased. This study demonstrates that EEG analysis can differentiate between clinical states (and loss of brain function at death) in birds and provides a unique integration of reflex responses and EEG activity. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Analysing responses to climate change through the lens of reflexivity.

    Science.gov (United States)

    Davidson, Debra

    2012-12-01

    Sociologists are increasingly directing attention toward social responses to climate change. As is true of any new field of inquiry, theoretical frameworks guiding the research to date have room for improvement. One advance could be achieved through closer engagement with Reflexivity Theory, particularly the work of Margaret Archer, who asks just how individuals come to give attention to certain problems, and formulate responses to them. Individuals vary significantly in regard to their understanding of and concern for anthropogenic climate change, and these standpoints in turn influence commitment to mitigation and adaptation. The emergent social interactions among all such agents in turn influence the morphogenetic trajectories through which social structures will evolve, but the role of 'meta-reflexives' is particularly crucial. Identifying pathways of individual climate change reflexivity can make a valuable contribution to our understanding of the potential for and nature of collective responses. In this paper, I explore climate change reflexivity, with particular attention to climate change meta-reflexives, through a qualitative analysis of personal interviews with residents of two small communities in Alberta, Canada. Applying Reflexivity Theory to this context articulates dimensions of reflexive processing not elaborated in current theoretical treatments, including future outlook and comfort with uncertainty, among others.

  12. Perceptual rivalry: reflexes reveal the gradual nature of visual awareness.

    Directory of Open Access Journals (Sweden)

    Marnix Naber

    Full Text Available Rivalry is a common tool to probe visual awareness: a constant physical stimulus evokes multiple, distinct perceptual interpretations ("percepts" that alternate over time. Percepts are typically described as mutually exclusive, suggesting that a discrete (all-or-none process underlies changes in visual awareness. Here we follow two strategies to address whether rivalry is an all-or-none process: first, we introduce two reflexes as objective measures of rivalry, pupil dilation and optokinetic nystagmus (OKN; second, we use a continuous input device (analog joystick to allow observers a gradual subjective report. We find that the "reflexes" reflect the percept rather than the physical stimulus. Both reflexes show a gradual dependence on the time relative to perceptual transitions. Similarly, observers' joystick deflections, which are highly correlated with the reflex measures, indicate gradual transitions. Physically simulating wave-like transitions between percepts suggest piece-meal rivalry (i.e., different regions of space belonging to distinct percepts as one possible explanation for the gradual transitions. Furthermore, the reflexes show that dominance durations depend on whether or not the percept is actively reported. In addition, reflexes respond to transitions with shorter latencies than the subjective report and show an abundance of short dominance durations. This failure to report fast changes in dominance may result from limited access of introspection to rivalry dynamics. In sum, reflexes reveal that rivalry is a gradual process, rivalry's dynamics is modulated by the required action (response mode, and that rapid transitions in perceptual dominance can slip away from awareness.

  13. Exercise-induced neuromuscular dysfunction under reflex conditions.

    Science.gov (United States)

    Kaufman, T; Burke, J R; Davis, J M; Durstine, J L

    2001-06-01

    The purpose of this research was to describe further the effects of exercise-induced muscle damage on reflex sensitivity. The subjects were eight physically active, but untrained males, between the ages of 18 and 29 years. The effects of eccentric and concentric exercise on patellar tendon reflex responses were determined. The 8 week experiment consisted of two, 5 day, test protocols with a 6 week wash-out period between test protocols. Each 5 day test protocol consisted of the following six test sessions: (1) day 1--baseline, (2) day 2 baseline, (3) day 2--immediate post-exercise, and (4-6) days 3-5: 24, 48, and 72 h post-exercise. On day 2, the subjects made either 100 fatiguing concentric or eccentric isotonic contractions using the right leg at 75% of the corresponding repetition maximum values. During each test session, the electromyogram (EMG) and force-time characteristics of basic and conditioned patellar tendon reflex responses were measured. The reflex amplitudes of basic and conditioned patellar tendon reflex responses were decreased following fatiguing concentric exercise. There were no immediate effects of fatiguing eccentric exercise on the basic and conditioned patellar tendon reflex responses, but the EMG amplitudes of these reflex responses were reduced on the days following eccentric exercise. The amount of conditioned patellar tendon reflex facilitation was decreased following the concentric exercise protocol and at 48 h post-eccentric exercise. Our conditioned reflex data suggest that post-exercise changes to the physiological mechanisms that modulate the recruitment gain of the alpha-motoneuron pool may depend upon the type of fatiguing exercise.

  14. Atypical Pupillary Light Reflex in Individuals with Autism

    Science.gov (United States)

    2014-09-01

    AWARD NUMBER: W81XWH-10-1-0474 TITLE: Atypical Pupillary Light Reflex in Individuals with Autism ...30th/2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-10-1-0474 Atypical Pupillary  Light  Reflex in Individuals with  Autism 5b. GRANT NUMBER...20,  p< .00005 in all instances].  15. SUBJECT TERMS Pupillary light reflex, autism , functional MRI 16. SECURITY CLASSIFICATION OF: 17

  15. [Human physiology: images and practices of the reflex].

    Science.gov (United States)

    Wübben, Yvonne

    2010-01-01

    The essay examines the function of visualizations and practices in the formation of the reflex concept from Thomas Willis to Marshall Hall. It focuses on the specific form of reflex knowledge that images and practices can contain. In addition, the essay argues that it is through visual representations and experimental practices that technical knowledge is transferred to the field of human reflex physiology. When using technical metaphors in human physiology authors often seem to feel obliged to draw distinctions between humans, machines and animals. On closer scrutiny, these distinctions sometimes fail to establish firm borders between the human and the technical.

  16. Development of sensory motor reflexes in 2 G exposed rats.

    Science.gov (United States)

    Wubbels, Réne; Bouët, Valentine; de Jong, Herman; Gramsbergen, Albert

    2004-07-01

    During gestation and early postnatal development, the animal's size and weight rapidly increase. Within that period, gravity affects sensory and motor development. We studied age-dependent modifications of several types of motor reflexes in 5 groups of rats conceived, born and reared in hypergravity (HG; 2 g). These rats were transferred to normal gravity (NG; 1 g) at various postnatal days, and their behavioral reflexes were compared with a control group which was constantly kept under NG. HG induced a retarded development of vestibular dependent reflexes. Other types of motor behavior were not delayed.

  17. Wavelet stretch correction%子波拉伸校正

    Institute of Scientific and Technical Information of China (English)

    黄文锋; 李宏兵; 姚逢昌; 李国平; 张佳佳

    2011-01-01

    依赖于偏移距的反射波调谐是AVO分析的不利因素.无论动校正还是偏移,都会引起子波拉伸、频谱向低频移动.在频率域对动校正或偏移后的地震数据进行反拉伸校正是本文消除子波拉伸采用的方法.从射线参数时距方程出发推导的地震映射压缩因子与反射角存在较精确的余弦关系.角度道中动校正或偏移子波拉伸因子是反射角余弦的倒数.用无拉伸子波频谱除以拉伸子波频谱得到反频谱压缩算子,对动校正或偏移后存在子波拉伸的角度道应用反频谱压缩算子,操作简单易行.薄层模型试验和实际地震资料处理表明角度道校正方法能够消除子波拉伸畸变,展宽频谱,补偿地震资料动校正或偏移过程中丢失的高频成分,提高大角度的分辨率和保真度,改善AVO分析.%Offset-dependent tuning includes seismic imaging tuning, NMO stretch, and migration stretch. Seismic imaging tuning caused by compression of reflectivity inheres in seismic record. Either NMO stretch or migration stretch is the wavelet stretch which arises in the seismic processing. They are adverse factors for AVO analysis. The goal of dynamic correction or migration is to modify the time difference measured at the mid- and the far-offset trace to that at the near-offset trace. Either dynamic correction or migration stretches the compressed reflectivity, but brings wavelet stretch and corresponding spectral compression at the same time. The method of removing wavelet stretch proposed in this article is to do anti-stretch correction on the seismic data after dynamic correction or migration in frequency domain. The compression factor of seismic imaging tuning deduced from the parametric ray equations is related closely to the cosine of the refection angle. In offset traces after dynamic correction or migration, the wavelet stretch factor which varies with time and velocity is nonstationary. The shallow reflection at the far

  18. Does the parental stretching programs improve metatarsus adductus in newborns?

    Science.gov (United States)

    Eamsobhana, Perajit; Rojjananukulpong, Karn; Ariyawatkul, Thanase; Chotigavanichaya, Chatupon; Kaewpornsawan, Kamolporn

    2017-01-01

    Metatarsus adductus (MA) is a common pediatric foot deformity. Current recommendations suggest observation until 4-6 months, then casting if the deformity persists. Based on our review of the literatures, no randomized controlled trial has been conducted to study the effectiveness of parental stretching in the correction of MA in newborn. Ninety-four newborn feet that were diagnosed as MA by clinical examination were enrolled. Feet were randomized into two groups: observation group and stretching group. Outcome measurements were performed to compare success rate between groups. According to Pearson's χ(2) test, there were no statistically significant differences between groups with regard to the overall success of the parental stretching program ( p = 0.191). There was also no significant difference between groups for mild degree or moderate-to-severe degree ( p = 0.134, p = 0.274, respectively). A more rapid success rate was observed in the stretching group at the first month follow-up, but rate of improvement then decreased. The stretching group tended to have a lower success rate compared to the observation group in moderate-to-severe feet, but the difference was not statistically significant. Parental stretching program found no benefit over observation group in this study. Parental stretching program should not be applied for newborn babies with moderate-to-severe MA as the result from the study appeared to have lower success rate compared to observation group. Observe until 4-6 months, then corrective casting for the persisting deformity is recommended.

  19. Cyclic stretching of soft substrates induces spreading and growth

    Science.gov (United States)

    Cui, Yidan; Hameed, Feroz M.; Yang, Bo; Lee, Kyunghee; Pan, Catherine Qiurong; Park, Sungsu; Sheetz, Michael

    2015-01-01

    In the body, soft tissues often undergo cycles of stretching and relaxation that may affect cell behaviour without changing matrix rigidity. To determine whether transient forces can substitute for a rigid matrix, we stretched soft pillar arrays. Surprisingly, 1–5% cyclic stretching over a frequency range of 0.01–10 Hz caused spreading and stress fibre formation (optimum 0.1 Hz) that persisted after 4 h of stretching. Similarly, stretching increased cell growth rates on soft pillars comparative to rigid substrates. Of possible factors linked to fibroblast growth, MRTF-A (myocardin-related transcription factor-A) moved to the nucleus in 2 h of cyclic stretching and reversed on cessation; but YAP (Yes-associated protein) moved much later. Knockdown of either MRTF-A or YAP blocked stretch-dependent growth. Thus, we suggest that the repeated pulling from a soft matrix can substitute for a stiff matrix in stimulating spreading, stress fibre formation and growth. PMID:25704457

  20. STRETCH FABRICS IN LEATHER MANUFACTURING: PERFORMANCE PROPERTIES OF STRECH LEATHERS

    Directory of Open Access Journals (Sweden)

    ORK Nilay

    2016-05-01

    Full Text Available Product variability of manufactured leather goods such as garment leathers could be closely related to the wear comfort because each material forming the garments are affected the comfort properties of the products. Considering the significant demand to elastic woven stretch fabrics and the advantages provided to leather goods like allowing easy body movements, well-fitting and keeping the shape make the use of stretch fabrics focus in interest. In this study, the performance properties of stretch leathers, leathers and spandex fabrics were presented and the differences between the characteristic properties of the leathers were described. For this purpose, physical characteristics of leathers were investigated in terms of thickness, weight, drape ability, stiffness, bending stiffness, air and water vapor permeability. The drape ability, stiffness and bending stiffness properties were significantly affected by the stretch fabrics laminated on the suede side of the leathers. The drape ability, stiffness and bending values were increased due to the implementation of stretch fabrics. There was no significant difference between the air permeability values of the leathers prior and after the implementation of stretch fabrics in contrast to water vapor permeability. The results of this study showed that the aesthetic behavior of clothing materials such as drape and stiffness properties as well as water vapor permeability was mainly affected from the implementation of the stretch fabrics.

  1. Primitive Reflexes and Attention-Deficit/Hyperactivity Disorder: Developmental Origins of Classroom Dysfunction

    Science.gov (United States)

    Taylor, Myra; Houghton, Stephen; Chapman, Elaine

    2004-01-01

    The present research studied the symptomatologic overlap of AD/HD behaviours and retention of four primitive reflexes (Moro, Tonic Labyrinthine Reflex [TLR], Asymmetrical Tonic Neck Reflex [ATNR], Symmetrical Tonic Neck Reflex [STNR]) in 109 boys aged 7-10 years. Of these, 54 were diagnosed with AD/HD, 34 manifested sub-syndromal coordination,…

  2. Plasticity of the cervico-ocular reflex in health and Disease

    NARCIS (Netherlands)

    W.P.A. Kelders (Willem)

    2006-01-01

    textabstractThe cervico-ocular reflex (COR) is an ocular stabilization reflex that is elicited by rotation of the neck. It works in conjunction with the vestibulo-ocular reflex (VOR) and the optokinetic reflex (OKR) in order to prevent visual slip over the retina due to self motion. The VOR

  3. Large-deviation statistics of vorticity stretching in isotropic turbulence.

    Science.gov (United States)

    Johnson, Perry L; Meneveau, Charles

    2016-03-01

    A key feature of three-dimensional fluid turbulence is the stretching and realignment of vorticity by the action of the strain rate. It is shown in this paper, using the cumulant-generating function, that the cumulative vorticity stretching along a Lagrangian path in isotropic turbulence obeys a large deviation principle. As a result, the relevant statistics can be described by the vorticity stretching Cramér function. This function is computed from a direct numerical simulation data set at a Taylor-scale Reynolds number of Re(λ)=433 and compared to those of the finite-time Lyapunov exponents (FTLE) for material deformation. As expected, the mean cumulative vorticity stretching is slightly less than that of the most-stretched material line (largest FTLE), due to the vorticity's preferential alignment with the second-largest eigenvalue of strain rate and the material line's preferential alignment with the largest eigenvalue. However, the vorticity stretching tends to be significantly larger than the second-largest FTLE, and the Cramér functions reveal that the statistics of vorticity stretching fluctuations are more similar to those of the largest FTLE. In an attempt to relate the vorticity stretching statistics to the vorticity magnitude probability density function in statistically stationary conditions, a model Kramers-Moyal equation is constructed using the statistics encoded in the Cramér function. The model predicts a stretched-exponential tail for the vorticity magnitude probability density function, with good agreement for the exponent but significant difference (35%) in the prefactor.

  4. Effects of special composite stretching on the swing of amateur golf players

    National Research Council Canada - National Science Library

    Lee, Joong-chul; Lee, Sung-wan; Yeo, Yun-ghi; Park, Gi Duck

    2015-01-01

    [Purpose] The study investigated stretching for safer a golf swing compared to present stretching methods for proper swings in order to examine the effects of stretching exercises on golf swings. [Subjects...

  5. DNA analysis by single molecule stretching in nanofluidic biochips

    DEFF Research Database (Denmark)

    Abad, E.; Juarros, A.; Retolaza, A.

    2011-01-01

    Stretching single DNA molecules by confinement in nanofluidic channels has attracted a great interest during the last few years as a DNA analysis tool. We have designed and fabricated a sealed micro/nanofluidic device for DNA stretching applications, based on the use of the high throughput Nano......-DNA stained with the fluorescent dye YOYO-1 were stretched in the nanochannel array and the experimental results were analysed to determine the extension factor of the DNA in the chip and the geometrical average of the nanochannel inner diameter. The determination of the extension ratio of the chip provides...

  6. Energy Method in Stretch Reducing Process of Steel Tube

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fang-ping; SUN Bin-yu; WANG Jian-mei

    2008-01-01

    According to the theories for stretch reducing process and steel tube plastic deformation,the energy method was used To mesh the rolled deformation zone of the steel tube into the upper limit elements,and an admissible velocity field was constructed to deduce a series of formulas of the inner virtual power consumption of deformed bodies.The rolling force during the stretch reducing process could be obtained by optimizing the upper limit power,which could provide guidelines for a proper choice of the stretch reducing process and devices for steel tube companies,as well as new products and devices.

  7. Temperature Field for Improving Internal Quality of Stretched Round Billet

    Institute of Scientific and Technical Information of China (English)

    QIU Ping; XIAO Hong

    2009-01-01

    Based on the rigid-plastic theory, using a coupled thermomechanieal model, the stretching process of a cir-cular section billet is simulated by means of FEM software Deform-2D. Through the distribution of internal stress fields of stretched round billet, it is found that the shear stress field is the main factor to induce Mannesmann's effect. The simulation results show that a reasonable distribution of the temperature field may improve the internal quality of the circular section billet in the stretching process.

  8. Structural Transitions in Supercoiled Stretched DNA

    Science.gov (United States)

    v, Croquette

    1998-03-01

    Using magnetic micromanipulation techniques [Strick 96]( uc(T.R.) Strick, J.-F. Allemand, D. Bensimon, A. Bensimon) and uc(V.) Croquette, "The elasticity of a single supercoiled DNA molecule", Science, 271, 1835 (1996)., we have studied the mechanical properties (force versus extension) of single DNA molecules under a wide range of torsional stresses (supercoiling). We show that unwinding the DNA double helix leads to a phase separation between regular B-DNA and denaturation bubbles. The fraction of denatured molecule increases linearly with the degree of unwinding, beginning at a value of 1% unwinding. We have confirmed this denatured state by hybridization of homologous single-stranded DNA probes and by a chemical attack of the exposed bases. Surprisingly, when we overwind the molecule, the elasticity curves we obtain may also be interpreted by the coexistence of two phases, B-DNA and a new phase which we note P-DNA. The fraction of this new phase increases smoothly with overwinding, beginning at 3 % and continuing up to 300 %. Our results indicate that this new phase is four times more twisted that the standard B-DNA and is 1.75 times longer. Although the structure of this phase is not yet known, such a high twisting can only be attained if the sugar-phosphate backbones of the two strands are twisted closely while the bases are expelled outside of the molecule's core, in a structure reminiscent of the one proposed by Pauling. Indeed we have shown that this new phase is sensitive to chemical attack whereas the B-DNA is not. This new phase begins to appear on a molecule overwound by 3 % and stretched by a force of 5 pN, conditions typically encountered in vivo during gene transcription. This new phase may thus play a biological role biophysique-ADN>(for more details).

  9. AI-augmented time stretch microscopy

    Science.gov (United States)

    Mahjoubfar, Ata; Chen, Claire L.; Lin, Jiahao; Jalali, Bahram

    2017-02-01

    Cell reagents used in biomedical analysis often change behavior of the cells that they are attached to, inhibiting their native signaling. On the other hand, label-free cell analysis techniques have long been viewed as challenging either due to insufficient accuracy by limited features, or because of low throughput as a sacrifice of improved precision. We present a recently developed artificial-intelligence augmented microscope, which builds upon high-throughput time stretch quantitative phase imaging (TS-QPI) and deep learning to perform label-free cell classification with record high-accuracy. Our system captures quantitative optical phase and intensity images simultaneously by frequency multiplexing, extracts multiple biophysical features of the individual cells from these images fused, and feeds these features into a supervised machine learning model for classification. The enhanced performance of our system compared to other label-free assays is demonstrated by classification of white blood T-cells versus colon cancer cells and lipid accumulating algal strains for biofuel production, which is as much as five-fold reduction in inaccuracy. This system obtains the accuracy required in practical applications such as personalized drug development, while the cells remain intact and the throughput is not sacrificed. Here, we introduce a data acquisition scheme based on quadrature phase demodulation that enables interruptionless storage of TS-QPI cell images. Our proof of principle demonstration is capable of saving 40 TB of cell images in about four hours, i.e. pictures of every single cell in 10 mL of a sample.

  10. Quantified reflex strategy using an iPod as a wireless accelerometer application.

    Science.gov (United States)

    LeMoyne, Robert; Mastroianni, Timothy; Grundfest, Warren

    2012-01-01

    A primary aspect of a neurological evaluation is the deep tendon reflex, frequently observed through the patellar tendon reflex. The reflex response provides preliminary insight as to the status of the nervous system. A quantified reflex strategy has been developed, tested, and evaluated though the use of an iPod as a wireless accelerometer application integrated with a potential energy device to evoke the patellar tendon reflex. The iPod functions as a wireless accelerometer equipped with robust software, data storage, and the capacity to transmit the recorded accelerometer waveform of the reflex response wirelessly through email for post-processing. The primary feature of the reflex response acceleration waveform is the maximum acceleration achieved subsequent to evoking the patellar tendon reflex. The quantified reflex strategy using an iPod as a wireless accelerometer application yields accurate and consistent quantification of the reflex response.

  11. Sensory and circuit mechanisms mediating lower urinary tract reflexes.

    Science.gov (United States)

    Danziger, Zachary C; Grill, Warren M

    2016-10-01

    Neural control of continence and micturition is distributed over a network of interconnected reflexes. These reflexes integrate sensory information from the bladder and urethra and are modulated by descending influences to produce different physiological outcomes based on the information arriving from peripheral afferents. Therefore, the mode of activation of primary afferents is essential in understanding the action of spinal reflex pathways in the lower urinary tract. We present an overview of sensory mechanisms in the bladder and urethra focusing on their spinal integration, identify the cardinal spinal reflexes responsible for continence and micturition, and describe how their functional role is controlled via peripheral afferent activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Trigemino-cervical reflex in patients with headache.

    Science.gov (United States)

    Milanov, I; Bogdanova, D

    2003-02-01

    Neurophysiological studies have shown abnormal activity of some brainstem nuclei in headache patients. The trigemino-cervical reflex is an anti-nociceptive reflex that gives an opportunity for evaluation of the brainstem interneurone activity. It has not been previously examined in headache patients. We studied 15 patients with predominantly unilateral chronic tension-type headache, 15 patients with migraine without aura and 32 healthy subjects. The trigemino-cervical reflex was recorded bilaterally from the resting sternocleidomastoid muscle using surface electromyographic recordings. In all headache patients the trigemino-cervical reflex on the painful side was with shortened latency compared with the non-painful side and with healthy persons. The results suggest decreased activity of the brainstem inhibitory interneurones. We suggest that although the pathophysiological mechanisms of tension-type headache and migraine are different, they share common mechanisms of abnormal pain control.

  13. Interindividual differences in H reflex modulation during normal walking

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Dyhre-Poulsen, Poul; Alkjaer, T

    2002-01-01

    Based on previous studies, at least two different types of soleus Hoffmann (H) reflex modulation were likely to be found during normal human walking. Accordingly, the aim of the present study was to identify different patterns of modulation of the soleus H reflex and to examine whether...... or not subjects with different H reflex modulation would exhibit different walking mechanics and different EMG activity. Fifteen subjects walked across two force platforms at 4.5 km/h (+/-10%) while the movements were recorded on video. The soleus H reflex and EMG activity were recorded separately during...... treadmill walking at 4.5 km/h. Using a two-dimensional analysis joint angles, angular velocities, accelerations, linear velocities and accelerations were calculated, and net joint moments about the ankle, knee and hip joint were computed by inverse dynamics from the video and force plate data. Six subjects...

  14. On the gastrocecal inhibitory reflex in the rat.

    Directory of Open Access Journals (Sweden)

    Lee,Zai-Liu

    1981-11-01

    Full Text Available In rats anesthetized with urethane, the effects of distention of the stomach upon cecal motility and neural mechanisms which generate this effect were studied. Cecal motility was inhibited which generate this effect were studied. Cecal motility was inhibited when the pars glandularis of the stomach was distended by pressure ranging from 25 to 30 cm H2O. This inhibitory reflex was not affected by bilateral cervical vagotomy, but completely abolished following bilateral severance of the greater splanchnic nerves or after intravenous administration of guanethidine. After transection of the spinal cord at the level of the 5th thoracic segment the inhibitory reflex remained intact, but was abolished following pithing of the 6th thoracic segment and below. It may be concluded that the afferent and efferent path of the gastrocecal inhibitory reflex mainly pass through the greater splanchnic nerves and the reflex center is located in thoracic segments caudal to the 6th thoracic segment.

  15. Reflexive Pronouns in Dagbani Samuel Alhassan Issah1 Abstract ...

    African Journals Online (AJOL)

    ... this paper. 1 Samuel Alhassan Issah teaches at the University of Education, Winneba. ..... This seems to suggest that the reflexive pronouns of Mandarian Chinese ... pronouns of Russian which are also argued to be non-local as argued by.

  16. Effects of contract-relax vs static stretching on stretch-induced strength loss and length-tension relationship.

    Science.gov (United States)

    Balle, S S; Magnusson, S P; McHugh, M P

    2015-12-01

    The purpose of this study was to determine the acute effects of contract-relax stretching (CRS) vs static stretching (SS) on strength loss and the length-tension relationship. We hypothesized that there would be a greater muscle length-specific effect of CRS vs SS. Isometric hamstring strength was measured in 20 healthy people at four knee joint angles (90°, 70°, 50°, 30°) before and after stretching. One leg received SS, the contralateral received CRS. Both stretching techniques resulted in significant strength loss, which was most apparent at short muscle lengths [SS: P = 0.025; stretching × angle P stretching × angle P stretch-induced strength loss was greater (P = 0.015) after CRS (11.7%) vs SS (3.7%). The muscle length effect on strength loss was not different between CRS and SS (stretching × angle × stretching technique P = 0.43). Contrary to the hypothesis, CRS did not result in a greater shift in the length-tension relationship, and in fact, resulted in greater overall strength loss compared with SS. These results support the use of SS for stretching the hamstrings.

  17. Neuroanatomical basis of Sandifer's syndrome: a new vagal reflex?

    Science.gov (United States)

    Cerimagic, Denis; Ivkic, Goran; Bilic, Ervina

    2008-01-01

    Sandifer's syndrome is a gastrointestinal disorder with neurological features. It is characterized by reflex torticollis following deglutition in patients with gastroesophageal reflux and/or hiatal hernia. The authors believe that neurological manifestations of the syndrome are the consequence of vagal reflex with the reflex center in nucleus tractus solitarii (NTS). Three models for the neuroanatomical basis of the hypothetic reflex arc are presented. In the first one the hypothetic reflex arc is based on the classic hypothesis of two components nervus accessorius (n.XI) - radix cranialis (RC) and radix spinalis (RS) The nervous impulses are transmitted by nervus vagus (n.X) general visceral afferent (GVA) fibers to NTS situated in medulla oblongata, then by interneuronal connections on nucleus ambiguus (NA) and nucleus dorsalis nervi vagi (NDX). Special visceral efferent fibers (SVE) impulses from NA are in part transferred to n.XI ramus externus (RE) (carrying the majority of general somatic efferent (GSE) fibers) via hypothetic anastomoses in the region of foramen jugulare. This leads to contraction of trapezius and sternocleidomastoideus muscles, and the occurrence of intermittent torticollis. In the second suggested neuroanatomical model the hypothetic reflex arc is organized in the absence of n.XI RC, the efferent part of the reflex arc continues as NA, which is motor nucleus of nervus glossopharyngeus (n.IX) and n.X in this case while distal roots of n.XI that appear at the level of the olivary nucleus lower edge represent n.X roots. In the third presented model the hypothetic reflex arc includes no jugular transfer and could be realized via interneuronal connections directly from NTS to the spinal motoneurons within nucleus radicis spinalis nervi accessorii (NRS n.XI) or from NA to NRS n.XI. The afferent segment of the postulated reflex arc in all three models is mediated via n.X. We conclude that Sandifer's syndrome is a clinical manifestation of another

  18. Estrogen attenuates the exercise pressor reflex in female cats.

    Science.gov (United States)

    Schmitt, Petra M; Kaufman, M P

    2003-10-01

    In humans, the pressor and muscle sympathetic nerve responses to static exercise are less in women than in men. The difference has been attributed to the effect of estrogen on the exercise pressor reflex. Estrogen receptors are abundant in areas of the dorsal horn receiving input from group III and IV muscle afferents, which comprise the sensory limb of the exercise pressor reflex arc. These findings prompted us to investigate the effect of estrogen on the spinal pathway of the exercise pressor reflex arc. Previously, we found that the threshold concentration of 17beta-estradiol needed to attenuate the exercise pressor reflex in male decerebrate cats was 10 microg/ml (Schmitt PM and Kaufman MP. J Appl Physiol 94: 1431-1436, 2003). The threshold concentration for female cats, however, is not known. Consequently, we applied 17beta-estradiol to a well covering the L6-S1 spinal cord in decerebrate female cats. The exercise pressor reflex was evoked by electrical stimulation of the L7 or S1 ventral root, a maneuver that caused the hindlimb muscles to contract statically. We found that the pressor response to contraction averaged 38 +/- 7 mmHg before the application of 17beta-estradiol (0.01 microg/ml) to the spinal cord, whereas it averaged only 23 +/- 4 mmHg 30 min after application (P effect on the exercise pressor reflex (n = 5). We conclude that the concentration of 17beta-estradiol required to attenuate the exercise pressor reflex is 1,000 times more dilute in female cats than that needed to attenuate this reflex in male cats.

  19. Impaired control of the oculomotor reflexes in Parkinson's disease

    OpenAIRE

    van Koningsbruggen, Martijn G.; Pender, Tom; Machado, Liana; Rafal, Robert D.

    2009-01-01

    To investigate the role of the basal ganglia in integrating voluntary and reflexive behaviour, the current study examined the ability of patients with Parkinson's disease to voluntarily control oculomotor reflexes. We measured the size of the fixation offset effect (the reduction in saccadic reaction time when a fixation point is removed) during a block of pro- and a block of anti-saccades. Healthy controls showed the expected reduction of the FOE during the anti-saccades, which results from ...

  20. An electronic device to record consensual reflex in human pupil.

    Science.gov (United States)

    Pinheiro, H M; Costa, R M; Camilo, E N R; Gang, Hua

    2015-01-01

    Examination of the pupil offers an objective evaluation of visual function as well as the vegetative pathways to the eye. This work proposes the development of an effective method and a portable device to test the consensual pupillary reflex. The first results demonstrate the success of a new device construction and methodology to record the consensual reflex with different stimulus, in a situation of complete blockage of light.

  1. Mechanical Characteristics of Reflex Durign Upright Posture in Paralyzed Subjects

    Science.gov (United States)

    Kim, Yongchul; Youm, Youngil; Lee, Bumsuk; Kim, Youngho; Choi, Hyeonki

    The characteristics of flexor reflexes have been investigated in the previous studies with human subjects who were seated or supine position. However, researchers did not describe how the spinal circuits are used in different hip angles for paralyzed subjects, such as the standing position with walker or cane. In upright posture the compatibility between a flexor reflex of leg and body balance is a special problem for lower limb injured subjects. Therefore, the purpose of this study was to investigate the effects of hip angle change on the flexor reflex evoked in standing paralyzed subjects supported by walker. In this study, six spinal cord injured and four stroke subjects were recruited through the inpatient physical therapy clinics of Korea national rehabilitation hospital. A single axis electronic goniometer was mounted on the lateral side of the hip joint of the impaired limb to record movements in the sagittal plane at this joint. The electronic goniometer was connected to a data acquisition system, through amplifiers to a computer. Since subject' posture influenced characteristics of the flexion reflex response, the subjects were supported in an upright posture by the help of parallelogram walder. Two series of tests were performed on each leg. The first series of the tests investigated the influence of hip angle during stationary standing posture on flexion reflex response. The hip angle was adjusted by the foot plate. The second examined the effect of the voluntary action of subject on swing motion during the gait. The electrically induced flexion reflex simultaneously produced the flexion of the hip, knee and dorsiflexion of the ankle enabling the swing phase of walking. Form the experimental results we observed that the reflex response of hip joint was largerwith the hip in the extended position than in the flexed position during standing posture. Under voluntary movement on flexion reflex during gaint, the peak hip angle induced by stimulation was

  2. An experimental psychophysiological approach to human bradycardiac reflexes.

    Science.gov (United States)

    Furedy, J J

    1985-01-01

    Bradycardic reflexes in man are both of scientific and clinical interest. Using the methods of experimental psychophysiology, control over relevant independent variables permits the study of fine-grained temporal physiologic response topographies, and of psychological factors that may modify the reflex. In addition, information can also be sought through interdisciplinary collaborations with experimental physiologists in order to shed light on the mechanism of the reflexes. These general features of the approach are illustrated by presenting data on two bradycardic reflex preparations: the laboratory dive analog, and the 90-degree negative tilt. The dive-analog studies have shown that a) the dive-reflex proper is a late-occurring bradycardia accompanied by a late-occurring vasoconstriction; and b) for the elicitation of this reflex, both breath-holding and face immersion are necessary. In addition, the physiologic manipulation of temperature affects the reflex in an inverse way over the range of 10 degrees to 40 degrees C, while the sense of control (a psychological variable) attenuates the reflex. The negative-tilt preparation produces a bradycardic response that is ideal as a Pavlovian unconditional response. Some Pavlovian conditioning arrangements, especially an "imaginational" form, do produce significant conditional bradycardic responding, and this has both potential clinical (e.g., biofeedback-related) and theoretical (e.g., S-R vs. S-S accounts of Pavlovian conditioning) applications. The paper ends with a comment on the cognitive paradigm shift in psychology. Although this shift is of importance, it is suggested that it is also important to "remember the response."

  3. Inhibitory reflex responses of masseter muscle in anterior open bite

    OpenAIRE

    Priyada, SANTILAKANAWONG; Hiroaki, KIRIMOTO; Yoichiro, SEKI; Kunimichi, SOMA; Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University

    2003-01-01

    Animal studies indicated that loss of occlusal contact between maxillary and mandibular teeth causes altered functional activity of periodontal mechanoreceptors. The alteration of periodontal mechanoreceptors may influence jawmuscle reflex and masticatory muscle activity. In this study, the inhibitory reflex response of masseter muscle in subjects with anterior open bite was investigated. The study population included 10 subjects with anterior open bite with no muscle pain or craniomandibular...

  4. Nasocardiac reflex during aspiration and injection through a nasogastric tube: An infrequent occurrence.

    Science.gov (United States)

    Haldar, Rudrashish; Kaur, Jasleen; Bajwa, Sukhminder Jit Singh

    2015-04-01

    Nasocardiac reflex is a relatively less discussed variant of trigeminovagal reflex where the afferent arc of the reflex is represented by any of the branches of the trigeminal nerves, and the efferent arc is via the vagus nerve. Elicitation of this reflex is commonly seen during surgical manipulation and is manifested as bradycardia or even asystole. We report a case where nasocardiac reflex was unusually observed in a patient when aspiration and injection were done through a nasogastric tube.

  5. Modulation of trigeminal reflex excitability in migraine: effects of attention and habituation on the blink reflex.

    Science.gov (United States)

    de Tommaso, Marina; Murasecco, Donatella; Libro, Giuseppe; Guido, Marco; Sciruicchio, Vittorio; Specchio, Luigi Maria; Gallai, Virgilio; Puca, Francomichele

    2002-06-01

    The modulation of trigeminal reflex excitability in migraine patients was evaluated during the asymptomatic phase by studying the effects of attention, habituation and preconditioning stimulus on the R2 and R3 components of the blink reflex (BR). Fifty patients suffering from migraine without aura, 20 affected by migraine with aura and 35 sex- and age-matched controls were selected. In subgroups of migraine with-aura and without-aura patients, and normal controls, the blink reflex was elicited during different cognitive situations: (a) spontaneous mental activity; (b) stimulus anticipation; (c) recognition of target numbers. In the remaining subjects, R2 and R3 habituation was evaluated by repetitive stimulation at 1, 5, 10, 15, 20, 25 and 30 s intervals. The R2 and R3 recovery curves were also computed. A reduced R3 threshold with a normal pain threshold was found in migraine with-aura and without-aura patients; the R3 component was not significantly correlated with the pain thresholds in patients and controls. The R2 and R3 components were less influenced by the warning of the stimulus in migraine without-aura and migraine with-aura patients, in comparison with the control group. A slight increase of both R2 and R3 recovery after preconditioning stimulus was also observed in migraine patients, probably caused by a phenomenon of trigeminal hyperexcitability persisting after the last attack. The abnormal BR modulation by alerting expresses in migraine a dysfunction of adaptation capacity to environmental conditions, probably predisposing to migraine.

  6. EMG and peak force responses to PNF stretching and the relationship between stretching-induced force deficits and bilateral deficits

    OpenAIRE

    2015-01-01

    [Purpose] The aim of the present study was to investigate the possibility of an interaction between stretching induced deficit (SFD) and bilateral deficits (BLD) during maximal voluntary isometric hand flexion under PNF stretch and no-stretch conditions through measurement of EMG and force production. [Subjects and Methods] Ten physically active male Caucasian students (age, 24.1±2.38 years; body mass, 79.48±11.40 kg; height, 174.15±0.8 cm) volunteered to participate in this study. EMG and fo...

  7. Vestibulocollic reflexes in the absence of head postural control.

    Science.gov (United States)

    Forbes, Patrick A; Siegmund, Gunter P; Happee, Riender; Schouten, Alfred C; Blouin, Jean-Sébastien

    2014-10-01

    Percutaneous electrical vestibular stimulation evokes reflexive responses in appendicular muscles that are suppressed during tasks in which the muscles are not contributing to balance control. In neck muscles, which stabilize the head on the torso and in space, it is unclear whether similar postural task dependence shapes vestibular reflexes. We investigated whether vestibulocollic reflexes are modulated during tasks in which vestibular information is not directly relevant to maintaining the head balanced on the torso. We hypothesized that vestibulocollic reflexes would be 1) evoked when neck muscles are not involved in balancing the head on the torso and 2) invariant across synergistic neck muscle contraction tasks. Muscle activity was recorded bilaterally in sternocleidomastoid and splenius capitis muscles during head-free and head-fixed conditions while subjects were exposed to stochastic electrical vestibular stimulation (± 5 mA, 0-75 Hz). Significant vestibular reflex responses (P reflex coupling, which we suggest functions through its closed-loop influence on head posture to ensure cervical spine stabilization. Copyright © 2014 the American Physiological Society.

  8. Damage percolation during stretch flange forming of aluminum alloy sheet

    Science.gov (United States)

    Chen, Zengtao; Worswick, Michael J.; Keith Pilkey, A.; Lloyd, David J.

    2005-12-01

    A multi-scale finite element (FE)-damage percolation model was employed to simulate stretch flange forming of aluminum alloys AA5182 and AA5754. Material softening and strain gradients were captured using a Gurson-based FE model. FE results were then fed into the so-called damage percolation code, from which the damage development was modelled within measured microstructures. The formability of the stretch flange samples was predicted based upon the onset of catastrophic failure triggered by profuse void coalescence within the measured second-phase particle field. Damage development is quantified in terms of crack and void areal fractions, and compared to metallographic results obtained from interrupted stretch flange specimens. Parametric study is conducted on the effect of void nucleation strain in the prediction of formability of stretch flanges to "calibrate" proper nucleation strains for both alloys.

  9. The weak fundamental NH-stretching transition in amines

    Science.gov (United States)

    Schrøder, Sidsel D.; Hansen, Anne S.; Wallberg, Jens H.; Nielsen, Anne R.; Du, Lin; Kjaergaard, Henrik G.

    2017-02-01

    Absolute intensities of NH-stretching fundamental and overtone transitions of gas phase aniline, methylamine, ethylamine, cyclopropylamine, methylethylamine, diethylamine and pyrrolidine have been measured with long path length conventional absorption spectroscopy. To support the assignments of NH-stretching transitions, transition frequencies and intensities were calculated with the local mode model using ab initio calculated local mode parameters and dipole moment functions obtained at the CCSD(T)-F12a/VDZ-F12 level of theory. For aniline, the absolute intensities of the NH-stretching transitions show the typical decrease of approximately an order of magnitude for each successive vibrational excitation. For methylamine, ethylamine, cyclopropylamine, methylethylamine, diethylamine and pyrrolidine, the observed absolute intensities of the fundamental NH-stretching transition is weak and of similar strength or even weaker than the corresponding first overtone transition. Characteristic for the amines with a normal fundamental intensity is a conjugated double bond next to the amine group.

  10. Optimal stretching of fluid for enhancing reaction growth

    Science.gov (United States)

    Nevins, Thomas; Kelley, Douglas

    2016-11-01

    When a biological or chemical scalar grows in flowing fluid, the resulting reacted region is dependent on both the details of the flow, and the reaction kinetics. We simultaneously film reaction state and flow in a laboratory model of reactive mixing in order to examine reactive mixing in physical, time-dependent flows. Using the excitable Belousov-Zhabotinsky (BZ) reaction, we find an optimal stretching range in which the flow enhances reaction, but larger stretching causes reaction blowout. We observe the transition from flow mostly helping to mostly blowout is not associated with the transition to turbulence, and that stretching fields (closely related to finite-time Lyapunov exponents) inside the optimal range appear to have a large effect on reaction growth rate locally. We also present estimates of the optimal stretching for BZ, and hypothesize that it is a feature exclusive to excitable reactions.

  11. Effects of Static Stretching and Playing Soccer on Knee Laxity

    NARCIS (Netherlands)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W.; Freiwald, Juergen

    2015-01-01

    Objective: This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Thirty-one athletes were randomly assigned into

  12. 600 Volt Stretched Lens Array for Solar Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past six years, ENTECH, Auburn, NASA, and other organizations have developed a new space photovoltaic array called the Stretched Lens Array (SLA), which...

  13. Guidelines for Stretch Flanging Advanced High Strength Steels

    Science.gov (United States)

    Sriram, S.; Chintamani, J.

    2005-08-01

    Advanced High Strength Steels (AHSS) are currently being considered for use in closure and structural panels in the automotive industry because of their high potential for affordable weight reduction and improved performance. AHSS such as dual phase steels are currently being used in some vehicle platforms. From a manufacturing perspective, stretch flanging during stamping is an important deformation mode requiring careful consideration of geometry and the die process. This paper presents some geometric and process guidelines for stretch flanging AHSS. Hole expansion experiments were conducted to determine the failure limit for a sheared edge condition. Effects of punching clearance, prestrain and prior strain path on hole expansion were explored in these experiments. In addition, dynamic explicit FE calculations using LS-DYNA were also conducted for a typical stretch flange by varying some key geometric parameters. The experimental and FEA results were then analyzed to yield process and geometric guidelines to enable successful stretch flanging of AHSS.

  14. Effects of Static Stretching and Playing Soccer on Knee Laxity

    NARCIS (Netherlands)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W.; Freiwald, Juergen

    2015-01-01

    Objective: This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Thirty-one athletes were randomly assigned into

  15. STUDIES ON ENHANCED CONDUCTIVITY OF STRETCHED CONDUCTING POLYMERS

    Institute of Scientific and Technical Information of China (English)

    WAN Meixiang

    1995-01-01

    A physical model of series of the conductivity on chain and the interchain conductivity between chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced conductivity for stretched conducting polymers might be due to increasing of the interchain conductivity between chains along the elongation direction after drawing processes if the conductivity on chain is assumed much larger than that of the interchain conductivity between chains. According to this model, it is expected that the temperature dependence of conductivity measured by four-probe method for stretched conducting polymers is controlled by a variation of the interchain conductivity between chains with temperature, which can be used to explain that a metallic temperature dependence of conductivity for stretched conducting polymers is not observed although the conductivity along the elongation direction is enhanced by two or three orders of magnitude.

  16. Measurement of Reversed Extension Flow using the Filament Stretch Rheometer

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann;

    2008-01-01

    The measurement of material functions with reversed extension flow is demonstrated using the Filament Stretching Rheometer (FSR). This includes startup of uniaxial elongational flow (potentially until steady state) followed by biaxial squeezing, and large amplitude oscillatory elongation (LAOE). ...

  17. Saturation of Zeldovich stretch-twist-fold map dynamos

    Science.gov (United States)

    Seta, Amit; Bhat, Pallavi; Subramanian, Kandaswamy

    2015-10-01

    > value is determined by the relative importance of the increased diffusion versus the reduced stretching. These saturation properties are akin to the range of possibilities that have been discussed in the context of fluctuation dynamos.

  18. Reflex anuria affecting both kidneys following hysterectomy

    Directory of Open Access Journals (Sweden)

    Gholyaf Mahmoud

    2009-01-01

    Full Text Available In situations when there is unilateral ureteral obstruction, the contralateral kidney retains its normal function. In rare instances however, it has been reported that unilateral ureteral obstruction can lead to reflex anuria (RA and acute renal failure (ARF. Even more unusually, RA with ARF can occur without organic obstruction due to ureteric manipulation during pelvic surgery. We report a 78- year-old woman, who underwent hysterectomy because of endometrial carcinoma. She developed ARF evidenced by anuria of 120-hours duration, and gradual rise of serum creatinine levels to 11.8 mg/dL on the fifth day after hysterectomy. Ultrasound study of the urinary tract revealed bilateral moderate hydronephrosis. Detailed evaluation did not reveal any organic obstruc-tion. She was managed with hemodialysis, control of hypertension and correction of fluid and elec-trolyte imbalances. By the sixth day, diuresis was established, and the blood urea and serum crea-tinine levels decreased to normal by the sixteenth day. The patient was finally discharged on the eighteenth day. Our case suggests that urologists and nephrologists should consider RA as one of the causes of anuria and ARF.

  19. Minimum Cost Homomorphisms to Reflexive Digraphs

    CERN Document Server

    Gupta, Arvind; Karimi, Mehdi; Rafiey, Arash

    2007-01-01

    For digraphs $G$ and $H$, a homomorphism of $G$ to $H$ is a mapping $f:\\ V(G)\\dom V(H)$ such that $uv\\in A(G)$ implies $f(u)f(v)\\in A(H)$. If moreover each vertex $u \\in V(G)$ is associated with costs $c_i(u), i \\in V(H)$, then the cost of a homomorphism $f$ is $\\sum_{u\\in V(G)}c_{f(u)}(u)$. For each fixed digraph $H$, the {\\em minimum cost homomorphism problem} for $H$, denoted MinHOM($H$), is the following problem. Given an input digraph $G$, together with costs $c_i(u)$, $u\\in V(G)$, $i\\in V(H)$, and an integer $k$, decide if $G$ admits a homomorphism to $H$ of cost not exceeding $k$. We focus on the minimum cost homomorphism problem for {\\em reflexive} digraphs $H$ (every vertex of $H$ has a loop). It is known that the problem MinHOM($H$) is polynomial time solvable if the digraph $H$ has a {\\em Min-Max ordering}, i.e., if its vertices can be linearly ordered by $<$ so that $i

  20. [Dissociated near reflex and accommodative convergence excess].

    Science.gov (United States)

    Gräf, M; Becker, R; Kloss, S

    2004-10-01

    We report on an 8-year-old boy whose near reflex could be elicited exclusively when the left eye was fixing (LF) but not when the right eye was fixing (RF). With RE +1.25/-1.25/169 degrees and LE +1.0/-0.75/24 degrees, the visual acuity was 1.0 OU at 5 m and RE 0.5, LE 1.0 at 0.3 m improving to 1.0 OU by a near addition of 3.0 D. Stereopsis was 100 degrees (Titmus test). The prism and cover test revealed an esophoria of 4 degrees at 5 m. At 3 m there was an esophoria of 6 degrees (RF) and an esotropia of 28 degrees (LF), compensating to an esophoria of 3 degrees (RF/LF) with a near addition of 3.0 D. Accommodation and the pupillary near reaction (OU) were hardly elicitable during RF. During LF, retinoscopy revealed an accommodation of 8 D (OU) and the pupils constricted normally. Correction by bifocal glasses yielded orthotropia with random dot stereopsis at near.

  1. A New Tool to Assess the Perception of Stretching Intensity.

    Science.gov (United States)

    Freitas, Sandro R; Vaz, João R; Gomes, Luis; Silvestre, Rui; Hilário, Edgar; Cordeiro, Nuno; Carnide, Filomena; Pezarat-Correia, Pedro; Mil-Homens, Pedro

    2015-09-01

    This study aimed to develop a valid and reliable scale to assess the perception of stretching intensity below and above the maximal range of motion. Experiments were conducted through a passive leg extension angle-torque assessment to healthy population (n = 90). In the study's first phase, the visual, numerical, and description of the stretching intensity scale (SIS) components were developed. The visual analog scale (VAS) score, absolute magnitude estimation (AME) score, and verbal stretching intensity symptom descriptors were assessed for different stretching intensities. In the second phase, the SIS was tested for validity, reliability, scale production, and estimation properties as well as responsiveness to stretching. In the first phase, a high correlation was found between SIS score and range of motion (ROM), as well as SIS and torque in both submaximal (intraclass correlation coefficient [ICC] = 0.89-0.99, r = 0.88-0.99) and supramaximal (ICC = 0.75-0.86, r = 0.68-0.88) stretching intensities. The AME and VAS scores fitted well in an exponential model for submaximal stretching intensities (y = 14.829e, ICC = 0.97 [0.83-0.99], r = 0.98), and in a linear model for supramaximal stretching intensities (y = 0.7667x - 25.751, ICC = 0.97 [0.89-0.99], r = 0.9594). For the second phase, a high correlation was found between SIS score and ROM (r = 0.70-0.76, ICC = 0.76-0.85), as well as SIS and torque (r = 0.62-0.88, ICC = 0.57-0.85). The interday reliability was high to produce (r = 0.70, ICC = 0.70 [0.50-0.83]) or estimate (r = 0.89, ICC = 0.89 [0.82-0.93]) stretching intensities. The acute stretching effects on ROM and passive torque were detectable using the SIS. It is expected a high application in assessing the stretch intensity using the SIS in future studies and practical interventions.

  2. Vibration-induced finger flexion reflex and inhibitory effect of acupuncture on this reflex in cervical spinal cord injury patients.

    Science.gov (United States)

    Takakura, N; Iijima, S; Kanamaru, A; Shibuya, M; Homma, I; Ohashi, M

    1996-12-01

    The vibration-induced finger flexion reflex (VFR) and the inhibitory effect of acupuncture on this reflex were studied in five cervical spinal cord injury patients (C-SCIs). VFR, which is a tonic finger flexion reflex induced by vibratory stimulation on the finger tip, was induced before and after acupuncture was carried out on the same hand. A stainless steel needle was inserted to the Hoku point. As in healthy subjects, VFR was performed and it was significantly inhibited by acupuncture in the C-SCIs; mean maximum VFR was 204.2 +/- S.E. 68.6 g before and 119.8 +/- S.E. 42.2 g after acupuncture. The present results suggest that at least part of the reflex center for VFR is located in the spinal cord and that part of VFR inhibition by acupuncture may be mediated via the spinal cord.

  3. STATIC STRETCHING DOES NOT REDUCE VARIABILITY, JUMP AND SPEED PERFORMANCE.

    Science.gov (United States)

    de Oliveira, Fábio Carlos Lucas; Rama, Luís Manuel Pinto Lopes

    2016-04-01

    Stretching is often part of the warm-up routine prior to athletic participation; however, controversial evidence exists on the effects of stretching on countermovement jump (CMJ) and sprint performance. Additionally, analysis of variability between repeated tasks is useful for monitoring players, to analyze factors that could affect the performance, and to guide clinical decisions for training strategies. The purpose of this study was to examine whether static stretching (SS) prior to CMJ and 20-meter (20-m) sprint would affect performance, and to investigate whether SS affects an athlete's ability to perform these tasks consistently. Twenty-two trained healthy athletes (23.2 ± 5.0 years) attended, randomly, two testing sessions, separated by 48 hours. At session one, all participants underwent 10 minutes of dynamic running warm-up followed by the experimental tasks (three CMJ and three 20-m sprint), whereas five minutes of stretching was added after the warm-up routine at session two. All participants performed the same experimental tasks in both sessions. The stretching protocol consisted of five stretching exercises for each lower limb. The paired-samples t-test revealed no significant differences between the stretching protocol condition and no stretching condition for the 20-m sprint (t(21)=.920; p=.368) and CMJ (t(21)=.709; p=.486). There were no significant differences in trial-by-trial variability on 20-m sprint (t(21)=1.934; p=.067) and CMJ scores (t(21)=.793; p=.437) as result of SS. The SS protocol did not modify jumping and running ability in trained healthy athletes. The SS prior to training or competition may not cause detrimental effects to athletic performance. Level III, Nonrandomized controlled trial.

  4. Pectoral stretching program for women undergoing radiotherapy for breast cancer.

    Science.gov (United States)

    Lee, T S; Kilbreath, S L; Refshauge, K M; Pendlebury, S C; Beith, J M; Lee, M J

    2007-05-01

    Surgery and radiotherapy commonly cause adverse musculoskeletal problems, particularly loss of strength and range of motion, in the upper quadrant of breast cancer patients. Few well-designed studies have investigated whether these impairments can be prevented. Stretching is an effective technique for increasing range of motion, hence the aim of this study was to investigate whether a stretching program reduced acute musculoskeletal impairments in patients undergoing radiotherapy for breast cancer. Sixty-four women were recruited prior to commencement of radiotherapy following breast cancer surgery. Participants were randomised to either a control or stretch group. Participants in both groups were reviewed by the physical therapist on a weekly basis for approximately 6 weeks, and were given general information about skin care and lymphedema. The control group received no advice about exercise. The stretch group received instruction on low-load, prolonged pectoral stretches, which were to be performed daily and were checked at weekly visits. Shoulder range of motion, strength, arm circumference, and quality of life measurements were taken prior to, and at completion of radiotherapy, and at 7 months after radiotherapy. There was no difference in any outcome between groups. Breast symptoms increased for both groups during radiotherapy, without loss of strength or range of movement. The incidence of lymphedema during the study was low for both groups and did not differ between groups. The pectoral stretching program did not influence the outcomes measured because the symptoms reported by patients were not a consequence of contracture.

  5. Efficacy of hamstring stretching programs in schoolchildren. A systematic review

    Directory of Open Access Journals (Sweden)

    Carlos-Alberto BECERRA FERNANDEZ

    2017-03-01

    Full Text Available The main purpose of the present review was to examine the scientific literature on the effects of physical education-based stretching programs on hamstring extensibility in schoolchildren aged 6-11 years. For this purpose relevant studies were searched from ten electronic databases dated up through May 2015. Of the 25 potentially relevant articles identified and retrieved for more detailed evaluation, only eight studies were included in the present review because they met the inclusion criteria. The overall results showed that incorporating hamstring stretching as a part of physical education classes produces a significant improvement in the scores of the tests: straight leg raise and classic sit-and-reach, for the experimental groups, but not for control groups. Stretching programs can be included in Physical Education classes, specifically during the warm-up and the cool down periods in order to improve hamstring extensibility. Although it seems that the stretching exercises in the warm-up period could be less effective in gaining flexibility in school children. Studies that use a stretching volume between 4 and 7 minutes per session and 2-4 training classes per week, obtain statistically significant improvements on the levels of hamstring flexibility in the experimental groups. However, after a five-week detraining period, children revert back to their initial flexibility levels. Therefore, it seems appropriate that physical education teachers should implement stretching programs to improve the students´ flexibility during the Physical Education classes.

  6. A model of cytoskeletal reorientation in response to substrate stretching

    Directory of Open Access Journals (Sweden)

    Lazopoulos K.A.

    2008-01-01

    Full Text Available Living adherent cells change their orientation in response to substrate stretching such that their cytoskeletal components reorganize in a new direction. To study this phenomenon, we model the cytoskeleton as a planar system of elastic cables and struts both pinned at their endpoints to a flat flexible substrate. Tensed (pre-strained cables represent acting stress fibers, whereas compression-bearing struts represent microtubules. We assume that in response to uniaxial substrate stretching the model reorients and deforms into a new configuration that minimizes its total potential energy. Using the Maxwell's global stability criterion, we find global minima configurations during static extension and compression of the substrate. Based on these results, we predict reorientation during cyclic stretching of the substrate. We find that in response to cyclic stretching cells either reorient transversely to the direction of stretching, or exhibit multiple configurations symmetrically distributed relative to the direction of stretching. These predictions are consistent with experimental data on living cells from the literature.

  7. Unsteady Viscous Flow over an Expanding Stretching Cylinder

    Institute of Scientific and Technical Information of China (English)

    方铁钢; 章骥; 钟永芳; 陶华

    2011-01-01

    We study the viscous How over an expanding stretching cylinder. The solution is exact to the Navier-Stokes equations. The stretching velocity of the cylinder is proportional to the axial distance from the origin and decreases with time. There exists a unique solution for the How with all the studied values of Reynolds number and the unsteadiness parameter. Reversal Hows exist for an expanding stretching cylinder. The velocity decays faster for a larger Reynolds number and a more rapidly expanding cylinder.%We study the viscous flow over an expanding stretching cylinder.The solution is exact to the Navier-Stokes equations.The stretching velocity of the cylinder is proportional to the axial distance from the origin and decreases with time.There exists a unique solution for the flow with all the studied values of Reynolds number and the unsteadiness parameter.Reversal flows exist for an expanding stretching cylinder.The velocity decays faster for a larger Reynolds number and a more rapidly expanding cylinder.

  8. Effects of Stretching Exercise on Heart Rate Variability During Pregnancy.

    Science.gov (United States)

    Logan, Jeongok G; Yeo, SeonAe

    Little evidence exists for effects of low-intensity exercises such as stretching on cardiovascular health in pregnant women. Our aim was to evaluate the effect of a 20-minute stretching exercise on heart rate variability (HRV), blood pressure (BP), and heart rate (HR) in healthy pregnant women. In 15 pregnant women with a mean (SD) age of 29.47 (4.07) years and mean (SD) gestational weeks of 26.53 (8.35), HRV, and BP were measured before and after the 20-minute stretching exercise. Compared with before the stretching exercise, standard deviation of the normal-to-normal intervals, total variability of heart rate, increased by 7.40 milliseconds (t = -2.31, P = .04) and root mean square of successive differences, a surrogate measure of parasympathetic outflow, also increased by 11.68 milliseconds (Z = -2.04, P = .04) after the stretching exercise. Diastolic BP and HR decreased by 2.13 mm Hg (t = 1.93, P = .07) and 3.31 bpm (t = 2.17, P = .05), respectively, but they did not reach statistical significance. These preliminary data suggest that 20 minutes of stretching exercise may promote cardiovascular health by attenuating the loss of parasympathetic tone associated with pregnancy.

  9. A reflective account on becoming reflexive: the 7 Cs of caring conversations as a framework for reflexive questioning

    Directory of Open Access Journals (Sweden)

    Edel Roddy

    2016-05-01

    Full Text Available Context: Some uncertainty surrounds both the definition and the application of reflexivity in participatory research and practice development. There is scope for further exploration of what reflexivity might look like in practice, and how the researcher/practice developer and participants might be involved. This paper does this in the context of a study that is using appreciative inquiry to explore the experience of inspection in care homes. Aims: I will explore my personal journey into the use of a relational constructionist approach to reflexivity and suggest that the 7 Cs of caring conversations provide a useful framework to inform reflexive practice. The 7 Cs will be used as a framework for the telling of this story. Implications for practice: Relational reflexivity has the potential to create the space for all those involved in research/practice development initiatives to voice their thoughts and feelings about the initiative and their involvement in it The 7 Cs of caring conversations can provide a framework for developing questions that may serve as a starting point for cultivating reflexive practice

  10. WEAKLY ALGEBRAIC REFLEXIVITY AND STRONGLY ALGEBRAIC REFLEXIVITY%弱代数性自反与强代数性自反

    Institute of Scientific and Technical Information of China (English)

    陶常利; 鲁世杰; 陈培鑫

    2002-01-01

    Algebraic reflexivity introduced by Hadwin is related to linear interpolation. In this paper, the concepts of weakly algebraic reflexivity and strongly algebraic reflexivity which are also related to linear interpolation are introduced. Some properties of them are obtained and some relations between them revealed.

  11. A method of reflexive balancing in a pragmatic, interdisciplinary and reflexive bioethics.

    Science.gov (United States)

    Ives, Jonathan

    2014-07-01

    In recent years there has been a wealth of literature arguing the need for empirical and interdisciplinary approaches to bioethics, based on the premise that an empirically informed ethical analysis is more grounded, contextually sensitive and therefore more relevant to clinical practice than an 'abstract' philosophical analysis. Bioethics has (arguably) always been an interdisciplinary field, and the rise of 'empirical' (bio)ethics need not be seen as an attempt to give a new name to the longstanding practice of interdisciplinary collaboration, but can perhaps best be understood as a substantive attempt to engage with the nature of that interdisciplinarity and to articulate the relationship between the many different disciplines (some of them empirical) that contribute to the field. It can also be described as an endeavour to explain how different disciplinary approaches can be integrated to effectively answer normative questions in bioethics, and fundamental to that endeavour is the need to think about how a robust methodology can be articulated that successfully marries apparently divergent epistemological and metaethical perspectives with method. This paper proposes 'Reflexive Bioethics' (RB) as a methodology for interdisciplinary and empirical bioethics, which utilizes a method of 'Reflexive Balancing' (RBL). RBL has been developed in response to criticisms of various forms of reflective equilibrium, and is built upon a pragmatic characterization of Bioethics and a 'quasi-moral foundationalism', which allows RBL to avoid some of the difficulties associated with RE and yet retain the flexible egalitarianism that makes it intuitively appealing to many.

  12. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

    LENUS (Irish Health Repository)

    O'Sullivan, Kieran

    2009-01-01

    BACKGROUND: Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. METHODS: A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. RESULTS: Across both groups, there was a significant main effect for time (p < 0.001). PKE ROM significantly increased with warm-up (p < 0.001). From warm-up, PKE ROM further increased with static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p < 0.001) after 15 minutes of rest, but remained significantly greater than at baseline (p < 0.001). Between groups, there was no main effect for group (p = 0.462), with no difference in mean PKE ROM values at any individual stage of the protocol (p > 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). CONCLUSION: Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced

  13. Effect of stretching-induced changes in hydrodynamic screening on coil-stretch hysteresis of unentangled polymer solutions

    Science.gov (United States)

    Prabhakar, Ranganathan; Sasmal, Chandi; Nguyen, Duc At; Sridhar, Tam; Prakash, J. Ravi

    2017-01-01

    Extensional rheometry and Brownian dynamics simulations of flexible polymer solutions confirm predictions based on blob concepts that coil-stretch hysteresis in extensional flows increases with concentration, reaching a maximum at the critical overlap concentration c* before progressively vanishing in the semidilute regime. These observations demonstrate that chain stretching strengthens intermolecular hydrodynamic screening in dilute solutions, but weakens it in semidilute solutions. Flow can thus strongly modify the concentration dependence of viscoelastic properties of polymer solutions.

  14. Cardiovascular Responses to Skeletal Muscle Stretching: "Stretching" the Truth or a New Exercise Paradigm for Cardiovascular Medicine?

    Science.gov (United States)

    Kruse, Nicholas T; Scheuermann, Barry W

    2017-08-05

    Stretching is commonly prescribed with the intended purpose of increasing range of motion, enhancing muscular coordination, and preventing prolonged immobilization induced by aging or a sedentary lifestyle. Emerging evidence suggests that acute or long-term stretching exercise may modulate a variety of cardiovascular responses. Specifically, at the onset of stretch, the mechanical deformation of the vascular bed coupled with stimulation of group III muscle afferent fibers initiates a cascade of events resulting in both peripheral vasodilation and a heart rate-driven increase in cardiac output, blood pressure, and muscle blood flow. This potential to increase shear stress and blood flow without the use of excessive muscle energy expenditure may hold important implications for future therapeutic vascular medicine and cardiac health. However, the idea that a cardiovascular component may be involved in human skeletal muscle stretching is relatively new. Therefore, the primary intent of this review is to highlight topics related to skeletal muscle stretching and cardiovascular regulation and function. The current evidence suggests that acute stretching causes a significant macro- and microcirculatory event that alters blood flow and the relationship between oxygen availability and oxygen utilization. These acute vascular changes if performed chronically may result in improved endothelial function, improved arterial blood vessel stiffness, and/or reduced blood pressure. Although several mechanisms have been postulated, an increased nitric oxide bioavailability has been highlighted as one promising candidate for the improvement in vessel function with stretching. Collectively, the evidence provided in this review suggests that stretching acutely or long term may serve as a novel and alternative low intensity therapeutic intervention capable of improving several parameters of vascular function.

  15. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

    Directory of Open Access Journals (Sweden)

    Murray Elaine

    2009-04-01

    Full Text Available Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM. 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1 at baseline; (2 after warm-up; (3 after stretch (static or dynamic and (4 after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Results Across both groups, there was a significant main effect for time (p 0.05. Using ANCOVA to adjust for the non-significant (p = 0.141 baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05. Conclusion Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. Trial Registration ACTRN12608000638336

  16. Stretching Rubber, Stretching Minds: a polymer physics lab for teaching entropy

    CERN Document Server

    Brzinski, Theodore A

    2015-01-01

    Entropy is a difficult concept to teach using real-world examples. Unlike temperature, pressure, volume, or work, it's not a quantity which most students encounter in their day-to-day lives. Even the way entropy is often qualitatively described, as a measure of disorder, is incomplete and can be misleading. In an effort to address these obstacles, we have developed a simple laboratory activity, the stretching of an elastic rubber sheet, intended to give students hands-on experience with the concepts of entropy, temperature and work in both adiabatic and quasistatic processes. We present two versions of the apparatus: a double-lever system, which may be reproduced with relatively little cost, and a commercial materials testing system, which provides students experience with scientific instrumentation that is used in research.

  17. Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs

    Science.gov (United States)

    Mezzarane, Rinaldo A.; Nakajima, Tsuyoshi; Zehr, E. Paul

    2017-01-01

    The modulation of spinal cord excitability during rhythmic limb movement reflects the neuronal coordination underlying actions of the arms and legs. Integration of network activity in the spinal cord can be assessed by reflex variability between the limbs, an approach so far very little studied. The present work addresses this question by eliciting Hoffmann (H-) reflexes in both limbs to assess if common drive onto bilateral pools of motoneurons influence spinal cord excitability simultaneously or with a delay between sides. A cross-covariance (CCV) sequence between reflexes in both arms or legs was evaluated under conditions providing common drive bilaterally through voluntary muscle contraction and/or rhythmic movement of the remote limbs. For H-reflexes in the flexor carpi radialis (FCR) muscle, either contraction of the FCR or leg cycling induced significant reduction in the amplitude of the peak at the zero lag in the CCV sequence, indicating independent variations in spinal excitability between both sides. In contrast, for H-reflexes in the soleus (SO) muscle, arm cycling revealed no reduction in the amplitude of the peak in the CCV sequence at the zero lag. This suggests a more independent control of the arms compared with the legs. These results provide new insights into the organization of human limb control in rhythmic activity and the behavior of bilateral reflex fluctuations under different motor tasks. From a functional standpoint, changes in the co-variability might reflect dynamic adjustments in reflex excitability that are subsumed under more global control features during locomotion. PMID:28725191

  18. The role of the superior laryngeal nerve in esophageal reflexes.

    Science.gov (United States)

    Lang, I M; Medda, B K; Jadcherla, S; Shaker, R

    2012-06-15

    The aim of this study was to determine the role of the superior laryngeal nerve (SLN) in the following esophageal reflexes: esophago-upper esophageal sphincter (UES) contractile reflex (EUCR), esophago-lower esophageal sphincter (LES) relaxation reflex (ELIR), secondary peristalsis, pharyngeal swallowing, and belch. Cats (N = 43) were decerebrated and instrumented to record EMG of the cricopharyngeus, thyrohyoideus, geniohyoideus, and cricothyroideus; esophageal pressure; and motility of LES. Reflexes were activated by stimulation of the esophagus via slow balloon or rapid air distension at 1 to 16 cm distal to the UES. Slow balloon distension consistently activated EUCR and ELIR from all areas of the esophagus, but the distal esophagus was more sensitive than the proximal esophagus. Transection of SLN or proximal recurrent laryngeal nerves (RLN) blocked EUCR and ELIR generated from the cervical esophagus. Distal RLN transection blocked EUCR from the distal cervical esophagus. Slow distension of all areas of the esophagus except the most proximal few centimeters activated secondary peristalsis, and SLN transection had no effect on secondary peristalsis. Slow distension of all areas of the esophagus inconsistently activated pharyngeal swallows, and SLN transection blocked generation of pharyngeal swallows from all levels of the esophagus. Slow distension of the esophagus inconsistently activated belching, but rapid air distension consistently activated belching from all areas of the esophagus. SLN transection did not block initiation of belch but blocked one aspect of belch, i.e., inhibition of cricopharyngeus EMG. Vagotomy blocked all aspects of belch generated from all areas of esophagus and blocked all responses of all reflexes not blocked by SLN or RLN transection. In conclusion, the SLN mediates all aspects of the pharyngeal swallow, no portion of the secondary peristalsis, and the EUCR and ELIR generated from the proximal esophagus. Considering that SLN is not

  19. Trigeminal Cardiac Reflex and Cerebral Blood Flow Regulation

    Science.gov (United States)

    Lapi, Dominga; Scuri, Rossana; Colantuoni, Antonio

    2016-01-01

    The stimulation of some facial regions is known to trigger the trigemino-cardiac reflex: the main stimulus is represented by the contact of the face with water. This phenomenon called diving reflex induces a set of reactions in the cardiovascular and respiratory systems occurring in all mammals, especially marine (whales, seals). During the immersion of the face in the water, the main responses are aimed at reducing the oxygen consumption of the organism. Accordingly reduction in heart rate, peripheral vasoconstriction, blood pooling in certain organs, especially the heart, and brain and an increase in blood pressure have been reported. Moreover, the speed and intensity of the reflex is inversely proportional to the temperature of the water: more cold the water, more reactions as described are strong. In the case of deep diving an additional effect, such as blood deviation, has been reported: the blood is sequestered within the lungs, to compensate for the increase in the external pressure, preventing them from collapsing. The trigeminal-cardiac reflex is not just confined to the diving reflex; recently it has been shown that a brief proprioceptive stimulation (10 min) by jaw extension in rats produces interesting effects both at systemic and cerebral levels, reducing the arterial blood pressure, and vasodilating the pial arterioles. The arteriolar dilation is associated with rhythmic diameter changes characterized by an increase in the endothelial activity. Fascinating the stimulation of trigeminal nerve is able to activate the nitric oxide release by vascular endothelial cells. Therefore, the aim of this review was to highlight the effects due to trigeminal cardiac reflex induced by a simple mandibular extension. Opposite effects, such as hypotension, and modulation of cerebral arteriolar tone, were observed, when these responses were compared to those elicited by the diving reflex. PMID:27812317

  20. Trigeminal cardiac reflex and cerebral blood flow regulation

    Directory of Open Access Journals (Sweden)

    Dominga Lapi

    2016-10-01

    Full Text Available The stimulation of some facial regions is known to trigger the trigemino-cardiac reflex: the main stimulus is represented by the contact of the face with water. This phenomenon called diving reflex induces a set of reactions in the cardiovascular and respiratory systems occurring in all mammals, especially marine (whales, seals. During the immersion of the face in the water, the main responses are aimed at reducing the oxygen consumption of the organism. Accordingly reduction in heart rate, peripheral vasoconstriction, blood pooling in certain organs, especially the heart and brain, and an increase in blood pressure have been reported. Moreover, the speed and intensity of the reflex is inversely proportional to the temperature of the water: more cold the water, more reactions as described are strong. In the case of deep diving an additional effect, such as blood deviation, has been reported: the blood is requested within the lungs, to compensate for the increase in the external pressure, preventing them from collapsing.The trigeminal-cardiac reflex is not just confined to the diving reflex; recently it has been shown that a brief proprioceptive stimulation (10 min by jaw extension in rats produces interesting effects both at systemic and cerebral level, reducing the arterial blood pressure and vasodilating the pial arterioles. The arteriolar dilation is associated with rhythmic diameter changes characterized by an increase in the endothelial activity. Fascinating the stimulation of trigeminal nerve is able to activated the nitric oxide release by vascular endothelial. Therefore the aim of this review was to highlight the effects due to trigeminal cardiac reflex induced by a simple mandibular extension, because produced opposite effects compared to those elicited by the diving reflex as it induces hypotension and modulation of cerebral arteriolar tone.