Academic literature on the topic 'Corticospinal responses'
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Journal articles on the topic "Corticospinal responses"
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Maier, Marc A., Peter A. Kirkwood, Thomas Brochier, and Roger N. Lemon. "Responses of single corticospinal neurons to intracortical stimulation of primary motor and premotor cortex in the anesthetized macaque monkey." Journal of Neurophysiology 109, no. 12 (June 15, 2013): 2982–98. http://dx.doi.org/10.1152/jn.01080.2012.
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The responses of individual primate corticospinal neurons to localized electrical stimulation of primary motor (M1) and of ventral premotor cortex (area F5) are poorly documented. To rectify this and to study interactions between responses from these areas, we recorded corticospinal axons, identified by pyramidal tract stimulation, in the cervical spinal cord of three chloralose-anesthetized macaque monkeys. Single stimuli (≤400 μA) were delivered to the hand area of M1 or F5 through intracortical microwire arrays. Only 14/112 (13%) axons showed responses to M1 stimuli that indicated direct intracortical activation of corticospinal neurons (D-responses); no D-responses were seen from F5. In contrast, 62 axons (55%) exhibited consistent later responses to M1 stimulation, corresponding to indirect activation (I-responses), showing that single-pulse intracortical stimulation of motor areas can result in trans-synaptic activation of a high proportion of the corticospinal output. A combined latency histogram of all axon responses was nonperiodic, clearly different from the periodic surface-recorded corticospinal volleys. This was readily explained by correcting for conduction velocities of individual axons. D-responding axons, taken as originating in neurons close to the M1 stimulating electrodes, showed more I-responses from M1 than those without a D-response, and 8/10 of these axons also responded to F5 stimulation. Altogether, 33% of tested axons responded to F5 stimulation, most of which also showed I-responses from M1. These excitatory effects are in keeping with facilitation of hand muscles evoked from F5 being relayed via M1. This was further demonstrated by facilitation of test responses from M1 by conditioning F5 stimuli.
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Taylor, J. L., and S. C. Gandevia. "Noninvasive stimulation of the human corticospinal tract." Journal of Applied Physiology 96, no. 4 (April 2004): 1496–503. http://dx.doi.org/10.1152/japplphysiol.01116.2003.
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Spinal tracts can be stimulated noninvasively in human subjects by passing a high-voltage stimulus between the mastoids or by magnetic stimulation over the back of the head. The stimulus probably activates the corticospinal tract at the cervicomedullary junction (pyramidal decussation) and evokes large, short-latency motor responses in the arm muscles. These responses have a large monosynaptic component. Responses in leg muscles can be elicited by cervicomedullary junction stimulation or by stimulation over the cervical or thoracic spine. Because nerve roots are more easily activated than spinal tracts, stimulus spread to motor axons can occur. Facilitation of responses by voluntary activity confirms that the responses are evoked synaptically. Stimulation of the corticospinal tract is useful in studies of central conduction and studies of the behavior of motoneurons during different tasks. It also provides an important comparison to allow interpretation of changes in responses to stimulation of the motor cortex. The major drawback to the use of electrical stimulation of the corticospinal tract is that each stimulus is transiently painful.
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Mason, Joel, Ashlyn K. Frazer, Janne Avela, Alan J. Pearce, Glyn Howatson, and Dawson J. Kidgell. "Tracking the corticospinal responses to strength training." European Journal of Applied Physiology 120, no. 4 (February 14, 2020): 783–98. http://dx.doi.org/10.1007/s00421-020-04316-6.
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Boyne, Pierce, Colleen Meyrose, Jennifer Westover, Dustyn Whitesel, Kristal Hatter, Darcy S. Reisman, David Cunningham, et al. "Exercise intensity affects acute neurotrophic and neurophysiological responses poststroke." Journal of Applied Physiology 126, no. 2 (February 1, 2019): 431–43. http://dx.doi.org/10.1152/japplphysiol.00594.2018.
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Aerobic exercise may acutely prime the brain to be more responsive to rehabilitation, thus facilitating neurologic recovery from conditions like stroke. This aerobic priming effect could occur through multiple mechanisms, including upregulation of circulating brain-derived neurotrophic factor (BDNF), increased corticospinal excitability, and decreased intracortical inhibition. However, optimal exercise parameters for targeting these mechanisms are poorly understood. This study tested the effects of exercise intensity on acute BDNF and neurophysiological responses. Sixteen ambulatory persons >6 mo poststroke performed three different 20-min exercise protocols in random order, approximately 1 wk apart, including the following: 1) treadmill high-intensity interval training (HIT-treadmill); 2) seated-stepper HIT (HIT-stepper); and 3) treadmill moderate-intensity continuous exercise (MCT-treadmill). Serum BDNF and transcranial magnetic stimulation measures of paretic lower limb excitability and inhibition were assessed at multiple time points during each session. Compared with MCT-treadmill, HIT-treadmill elicited significantly greater acute increases in circulating BDNF and corticospinal excitability. HIT-stepper initially showed BDNF responses similar to HIT-treadmill but was no longer significantly different from MCT-treadmill after decreasing the intensity in reaction to two hypotensive events. Additional regression analyses showed that an intensity sufficient to accumulate blood lactate appeared to be important for eliciting BDNF responses, that the interval training approach may have facilitated the corticospinal excitability increases, and that the circulating BDNF response was (negatively) related to intracortical inhibition. These findings further elucidate neurologic mechanisms of aerobic exercise and inform selection of optimal exercise-dosing parameters for enhancing acute neurologic effects. NEW & NOTEWORTHY Acute exercise-related increases in circulating BDNF and corticospinal excitability are thought to prime the brain for learning. Our data suggest that these responses can be obtained among persons with stroke using short-interval treadmill high-intensity interval training, that a vigorous aerobic intensity sufficient to generate lactate accumulation is needed to increase BDNF, that interval training facilitates increases in paretic quadriceps corticospinal excitability, and that greater BDNF response is associated with lesser intracortical inhibition response.
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Mason, Joel, Ashlyn K. Frazer, Alan J. Pearce, Alicia M. Goodwill, Glyn Howatson, Shapour Jaberzadeh, and Dawson J. Kidgell. "Determining the early corticospinal-motoneuronal responses to strength training: a systematic review and meta-analysis." Reviews in the Neurosciences 30, no. 5 (July 26, 2019): 463–76. http://dx.doi.org/10.1515/revneuro-2018-0054.
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Abstract Several studies have used transcranial magnetic stimulation to probe the corticospinal-motoneuronal responses to a single session of strength training; however, the findings are inconsistent. This systematic review and meta-analysis examined whether a single bout of strength training affects the excitability and inhibition of intracortical circuits of the primary motor cortex (M1) and the corticospinal-motoneuronal pathway. A systematic review was completed, tracking studies between January 1990 and May 2018. The methodological quality of studies was determined using the Downs and Black quality index. Data were synthesised and interpreted from meta-analysis. Nine studies (n=107) investigating the acute corticospinal-motoneuronal responses to strength training met the inclusion criteria. Meta-analyses detected that after strength training compared to control, corticospinal excitability [standardised mean difference (SMD), 1.26; 95% confidence interval (CI), 0.88, 1.63; p<0.0001] and intracortical facilitation (ICF) (SMD, 1.60; 95% CI, 0.18, 3.02; p=0.003) were increased. The duration of the corticospinal silent period was reduced (SMD, −17.57; 95% CI, −21.12, −14.01; p=0.00001), but strength training had no effect on the excitability of the intracortical inhibitory circuits [short-interval intracortical inhibition (SICI) SMD, 1.01; 95% CI, −1.67, 3.69; p=0.46; long-interval intracortical inhibition (LICI) SMD, 0.50; 95% CI, −1.13, 2.13; p=0.55]. Strength training increased the excitability of corticospinal axons (SMD, 4.47; 95% CI, 3.45, 5.49; p<0.0001). This systematic review and meta-analyses revealed that the acute neural changes to strength training involve subtle changes along the entire neuroaxis from the M1 to the spinal cord. These findings suggest that strength training is a clinically useful tool to modulate intracortical circuits involved in motor control.
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Cherni, Yosra, Alexia Tremblay, Margaux Simon, Floriane Bretheau, Andréanne K. Blanchette, and Catherine Mercier. "Corticospinal Responses Following Gait-Specific Training in Stroke Survivors: A Systematic Review." International Journal of Environmental Research and Public Health 19, no. 23 (November 24, 2022): 15585. http://dx.doi.org/10.3390/ijerph192315585.
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Corticospinal excitability is subject to alterations after stroke. While the reversal of these alterations has been proposed as an underlying mechanism for improved walking capacity after gait-specific training, this has not yet been clearly demonstrated. Therefore, the objective of this review is to evaluate the effect of gait-specific training on corticospinal excitability in stroke survivors. We conducted an electronic database search in four databases (i.e., Medline, Embase, CINAHL and Web of Science) in June 2022. Two authors screened in an independent way all the studies and selected those that investigated the effect of gait-specific training on variables such as motor-evoked potential amplitude, motor threshold, map size, latency, and corticospinal silent period in stroke survivors. Nineteen studies investigating the effect of gait-specific training on corticospinal excitability were included. Some studies showed an increased MEP amplitude (7/16 studies), a decreased latency (5/7studies), a decreased motor threshold (4/8 studies), an increased map size (2/3 studies) and a decreased cortical silent period (1/2 study) after gait-specific training. No change has been reported in terms of short interval intracortical inhibition after training. Five studies did not report any significant effect after gait-specific training on corticospinal excitability. The results of this systematic review suggest that gait-specific training modalities can drive neuroplastic adaptation among stroke survivors. However, given the methodological disparity of the included studies, additional clinical trials of better methodological quality are needed to establish conclusions. The results of this review can therefore be used to develop future studies to better understand the effects of gait-specific training on the central nervous system.
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Forman, Davis A., Garrick N. Forman, Bernadette A. Murphy, and Michael W. R. Holmes. "Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions on Corticospinal Excitability to Forearm Muscles during Low-Intensity Hand-Gripping." Brain Sciences 10, no. 7 (July 13, 2020): 445. http://dx.doi.org/10.3390/brainsci10070445.
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The wrist extensors demonstrate an earlier fatigue onset than the wrist flexors. However, it is currently unclear whether fatigue induces unique changes in muscle activity or corticospinal excitability between these muscle groups. The purpose of this study was to examine how sustained isometric wrist extension/flexion maximal voluntary contractions (MVCs) influence muscle activity and corticospinal excitability of the forearm. Corticospinal excitability to three wrist flexors and three wrist extensors were measured using motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation. Responses were elicited while participants exerted 10% of their maximal handgrip force, before and after a sustained wrist flexion or extension MVC (performed on separate sessions). Post-fatigue measures were collected up to 10-min post-fatigue. Immediately post-fatigue, extensor muscle activity was significantly greater following the wrist flexion fatigue session, although corticospinal excitability (normalized to muscle activity) was greater on the wrist extension day. Responses were largely unchanged in the wrist flexors. However, for the flexor carpi ulnaris, normalized MEP amplitudes were significantly larger following wrist extension fatigue. These findings demonstrate that sustained isometric flexion/extension MVCs result in a complex reorganization of forearm muscle recruitment strategies during hand-gripping. Based on these findings, previously observed corticospinal behaviour following fatigue may not apply when the fatiguing task and measurement task are different.
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Škarabot, Jakob, Paul Ansdell, Callum G. Brownstein, Kirsty M. Hicks, Glyn Howatson, Stuart Goodall, and Rade Durbaba. "Reduced corticospinal responses in older compared with younger adults during submaximal isometric, shortening, and lengthening contractions." Journal of Applied Physiology 126, no. 4 (April 1, 2019): 1015–31. http://dx.doi.org/10.1152/japplphysiol.00987.2018.
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The aim of this study was to assess differences in motor performance, as well as corticospinal and spinal responses to transcranial magnetic and percutaneous nerve stimulation, respectively, during submaximal isometric, shortening, and lengthening contractions between younger and older adults. Fifteen younger [26 yr (SD 4); 7 women, 8 men] and 14 older [64 yr (SD 3); 5 women, 9 men] adults performed isometric and shortening and lengthening dorsiflexion on an isokinetic dynamometer (5°/s) at 25% and 50% of contraction type-specific maximums. Motor evoked potentials (MEPs) and H reflexes were recorded at anatomical zero. Maximal dorsiflexor torque was greater during lengthening compared with shortening and isometric contractions ( P < 0.001) but was not age dependent ( P = 0.158). However, torque variability was greater in older compared with young adults ( P < 0.001). Background electromyographic (EMG) activity was greater in older compared with younger adults ( P < 0.005) and was contraction type dependent ( P < 0.001). As evoked responses are influenced by both the maximal level of excitation and background EMG activity, the responses were additionally normalized {[MEP/maximum M wave (Mmax)]/root-mean-square EMG activity (RMS) and [H reflex (H)/Mmax]/RMS}. (MEP/Mmax)/RMS and (H/Mmax)/RMS were similar across contraction types but were greater in young compared with older adults ( P < 0.001). Peripheral motor conduction times were prolonged in older adults ( P = 0.003), whereas peripheral sensory conduction times and central motor conduction times were not age dependent ( P ≥ 0.356). These data suggest that age-related changes throughout the central nervous system serve to accommodate contraction type-specific motor control. Moreover, a reduction in corticospinal responses and increased torque variability seem to occur without a significant reduction in maximal torque-producing capacity during older age. NEW & NOTEWORTHY This is the first study to have explored corticospinal and spinal responses with aging during submaximal contractions of different types (isometric, shortening, and lengthening) in lower limb musculature. It is demonstrated that despite preserved maximal torque production capacity corticospinal responses are reduced in older compared with younger adults across contraction types along with increased torque variability during dynamic contractions. This suggests that the age-related corticospinal changes serve to accommodate contraction type-specific motor control.
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Krishnan, Chandramouli, Edward P. Washabaugh, Aviroop Dutt-Mazumder, Scott R. Brown, Edward M. Wojtys, and Riann M. Palmieri-Smith. "Conditioning Brain Responses to Improve Quadriceps Function in an Individual With Anterior Cruciate Ligament Reconstruction." Sports Health: A Multidisciplinary Approach 11, no. 4 (April 5, 2019): 306–15. http://dx.doi.org/10.1177/1941738119835163.
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Background: Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction. Hypothesis: Operant conditioning of motor evoked torque responses would improve quadriceps strength, voluntary activation, and corticospinal excitability. Study Design: Case study and research report. Level of Evidence: Level 5. Methods: A 24-year-old male with an ACL reconstruction (6 months postsurgery) trained for 20 sessions (2-3 times per week for 8 weeks) to increase his TMS-induced motor evoked torque response (MEP torque) of the quadriceps muscles using operant conditioning principles. Knee extensor strength, voluntary quadriceps muscle activation, and quadriceps corticospinal excitability were evaluated at 3 time points: preintervention (pre), 4 weeks (mid), and immediately after the intervention (post). Results: The participant was able to successfully condition (ie, increase) the quadriceps MEP torque after 1 training session, and the conditioned MEP torque gradually increased over the course of 20 training sessions to reach about 500% of the initial value at the end of training. The participant’s control MEP torque values and corticospinal excitability, which were measured outside of the conditioning paradigm, also increased with training. These changes were paralleled by improvements in knee extensor strength and voluntary quadriceps muscle activation. Conclusion: This study shows that operant conditioning of MEP torque is a feasible approach to improving quadriceps corticospinal excitability and quadriceps function after ACL reconstruction and encourages further testing in a larger cohort of ACL-reconstructed individuals. Clinical Relevance: Operant conditioning may serve as a potential therapeutic adjuvant for ACL rehabilitation.
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Sidhu, Simranjit K., Ben W. Hoffman, Andrew G. Cresswell, and Timothy J. Carroll. "Corticospinal contributions to lower limb muscle activity during cycling in humans." Journal of Neurophysiology 107, no. 1 (January 2012): 306–14. http://dx.doi.org/10.1152/jn.00212.2011.
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The purpose of the current study was to investigate corticospinal contributions to locomotor drive to leg muscles involved in cycling. We studied 1) if activation of inhibitory interneurons in the cortex via subthreshold transcranial magnetic stimulation (TMS) caused a suppression of EMG and 2) how the responses to stimulation of the motor cortex via TMS and cervicomedullary stimulation (CMS) were modulated across the locomotor cycle. TMS at intensities subthreshold for activation of the corticospinal tract elicited suppression of EMG for approximately one-half of the subjects and muscles during cycling, and in matched static contractions in vastus lateralis. There was also significant modulation in the size of motor-evoked potentials (MEPs) elicited by TMS across the locomotor cycle ( P < 0.001) that was strongly related to variation in background EMG in all muscles ( r > 0.86; P < 0.05). When MEP and CMEP amplitudes were normalized to background EMG, they were relatively larger prior to the main EMG burst and smaller when background EMG was maximum. Since the pattern of modulation of normalized MEP and CMEP responses was similar, the data suggest that phase-dependent modulation of corticospinal responses during cycling in humans is driven mainly by spinal mechanisms. However, there were subtle differences in the degree to which normalized MEP and CMEP responses were facilitated prior to EMG burst, which might reflect small increases in cortical excitability prior to maximum muscle activation. The data demonstrate that the motor cortex contributes actively to locomotor drive, and that spinal factors dominate phase-dependent modulation of corticospinal excitability during cycling in humans.
Dissertations / Theses on the topic "Corticospinal responses"
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Bucchioni, Giulia. "Study of postural, physiological and corticospinal responses in empathy for pain and pain anticipation." Thesis, Amiens, 2015. http://www.theses.fr/2015AMIE0029/document.
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L'empathie nous permet de comprendre et de réagir aux sensations des autres individus. Regarder une situation douloureuse peut induire des comportements de type prosociaux orientés vers les autres ou des réponses d'évitement comme celles enregistrées en réponse à une menace. Le but principal de cette thèse était d'étudier les comportements d'approche/évitement et freezing qui se produisent soit en observant la douleur des autres, soit pendant l'anticipation de la douleur. Deux tâches manipulant la prise de perspective ont permis d'enregistrer des cotations supérieures concernant le niveau de douleur, des temps de réaction inférieurs (expérience 1) et des index de réponses d'évitement plus grands (expérience 2) pour la perspective consistant à imaginer que le sujet représenté dans une condition douloureuse était la personne la plus aimée. Dans la troisième expérience, nous avons analysé le comportement du freezing au niveau du système corticospinal du participant : un effet du freezing spécifique fut rapporté uniquement lorsque de la présentation des stimuli douloureux en perspective du première personne. Dans une quatrième expérience, l'effet du freezing, normalement présent en réponse aux stimuli douloureux fut aussi rapporté dans le cadre de l'anticipation de la douleur pour soi-même. Nos études suggèrent que ce sont principalement les mécanismes cognitifs de prise de perspective qui modulent la réponse empathique et que la perspective de la personne la plus aimée induise la réponse empathique la plus forte. Au contraire les réponses du freezing des modulations corticospinales sont principalement observées lorsque le sujet adopte une perspective en première personneEmpathy allows us to understand and react to other people feelings. Regarding empathy for pain, a witness looking at a painful situation may react to other-oriented and prosocial-altruistic behaviors or self-oriented withdrawal responses. The main aim of this thesis was to study approach/avoidance and freezing behavioral manifestations that co-occurring along with both others’ pain observation and during the anticipation of pain. In two perspective-taking tasks, we investigated the influence of the type of relationship between the witness and the target in pain. Results showed that higher pain ratings, lower reactions times (experiment 1) and greater withdrawal avoidance postural responses (experiment 2) were attributed when participants adopted their most loved person perspective. In experiment 3, we analyzed the freezing behavior in the observer’s corticospinal system while subject was observing painful stimuli in first-and third-person perspectives. Results showed the pain-specific freezing effect only pertained to the first-person perspective condition. An empathy for pain interpretation suggests empathy might represent the anticipation of painful stimulation in oneself. In experiment 4 results, we found that the freezing effect present during a painful electrical stimulation was also present in the anticipation of pain. In conclusion, our studies suggest that cognitive perspective-taking mechanisms mainly modulate the empathic response and the most loved person perspective seems to be prevalent. In addition, more basic pain-specific corticospinal modulations are mainly present in the first-person perspective and it seems to not be referred to the empathy components
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Tallent, Jamie. "Corticospinal and spinal responses and adaptations from shortening and lengthening resistance training and subsequent detraining." Thesis, Northumbria University, 2014. http://nrl.northumbria.ac.uk/21429/.
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Maximising strength and neurological adaptations to resistance training has long been sought to improve athletic performance and enhance clinical rehabilitation functional outcomes. In recent years, transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS) have been applied to investigate changes in the central nervous system (CNS). Conventional resistance training programmes consist of shortening and lengthening muscle contractions and have been shown to have uniquely different motor control strategies; how this neurological control is modified during specific muscle contraction resistance training is unknown. Additionally, understanding the detraining process will assist in designing tapers for elite athletes and improve our knowledge of detraining and inactivity in other populations. The overall aim of the thesis was to determine the TMS and PNS responses to, and following, shortening and lengthening resistance exercise and subsequent detraining.
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Hill, Caitlin E. "Contusive Spinal Cord Injury: Endogenous Responses of Descending Systems and Effects of Acute Transplantion of Glial Restricted Precursor Cells." Connect to this title online, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1032795301.
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Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xiii, 177 p.; also includes graphics (some col.). Includes bibliographical references (p. 160-177). Available online via OhioLINK's ETD Center
Books on the topic "Corticospinal responses"
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Deletis, Vedran, Francesco Sala, and Sedat Ulkatan. Transcranial electrical stimulation and intraoperative neurophysiology of the corticospinal tract. Edited by Charles M. Epstein, Eric M. Wassermann, and Ulf Ziemann. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780198568926.013.0008.
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Transcranial electrical stimulation is a well-recognized method for corticospinal tract (CT) activation. This article explains the use of TES during surgery and highlights the physiology of the motor-evoked potentials (MEPs). It describes the techniques and methods for brain stimulation and recording of responses. There are two factors that determine the depth of the current penetrating the brain, they are: choice of electrode montage for stimulation over the scalp and the intensity of stimulation. D-wave collision technique is a newly developed technique that allows mapping intraoperatively and finding the anatomical position of the CT within the surgically exposed spinal cord. Different mechanisms may be involved in the pathophysiology of postoperative paresis in brain and spinal cord surgeries so that different MEP monitoring criteria can be used to avoid irreversible damage and accurately predict the prognosis.
Book chapters on the topic "Corticospinal responses"
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Katayama, Y., T. Tsubokawa, S. Maejima, T. Hirayama, and T. Yamamoto. "Corticospinal Direct Response to Stimulation of the Exposed Motor Cortex in Humans." In Neurophysiology and Standards of Spinal Cord Monitoring, 100–105. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3804-1_13.
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Mauricio, Elizabeth A. "Motor Evoked Potentials." In Clinical Neurophysiology, edited by Devon I. Rubin, 747–60. 5th ed. Oxford University PressNew York, 2021. http://dx.doi.org/10.1093/med/9780190067854.003.0041.
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Abstract Motor evoked potentials can be generated by either electrical or magnetic stimulation of the corticospinal pathways. Direct activation of pyramidal cells and indirect activation of cortical interneurons generate impulses that propagate down the spinal cord as D-waves and I-waves, ultimately stimulating anterior horn cells and resulting in M-waves recorded over the targeted muscle. Transcranial electrical stimulation is most commonly employed in the operating room for intraoperative neurophysiologic monitoring, ensuring that the integrity of the motor pathways are preserved during brain or spine surgeries. The utility of transcranial magnetic stimulation has been explored in many neurologic diseases, where alterations in central motor conduction time and cortical excitability may provide important clues in diagnosis, prognosis, and monitoring response to treatment.
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Tetzlaff, W., N. R. Kobayashi, K. M. G. Giehl, B. J. Tsui, S. L. Cassar, and A. M. Bedard. "Chapter 22 Response of rubrospinal and corticospinal neurons to injury and neurotrophins." In Neural Regeneration, 271–86. Elsevier, 1994. http://dx.doi.org/10.1016/s0079-6123(08)61142-5.
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van Gerpen, Jay A., and John N. Caviness. "Long Latency Reflexes and the Silent Period." In Clinical Neurophysiology, 700–706. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780190259631.003.0042.
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Long latency reflexes (LLRs) are EMG activity occurring during the transition from reflex to voluntary motor activity, which probably arise from a transcortical loop, including afferents within the dorsal column/medial lemniscal system to the sensorimotor cortex and corticospinal tract efferents. Depending upon the site of a lesion and its pathophysiology, LLRs may be absent, delayed, or enhanced. In disorders of cortical hyperexcitability, including cortical myoclonus, an LLR occurring 40–60 ms after stimulation of the median nerve at rest may be present (“C-reflex.”) In response to noxious stimuli to the lower extremities, a polysynaptic network of spinal neurons, flexor reflex afferents, induce a patterned withdrawal response, including hip and knee flexion. These flexor reflexes may aid in the diagnosis of disorders of spinal cord hyperexcitability. Normally, following high stimulation of a peripheral nerve innervating a muscle that is being strongly contracted, no electrical activity occurs for approximately 100 ms (“silent period.”_ In disorders of distal peripheral nerve or muscle hyperexcitability, the silent period may be absent.
Conference papers on the topic "Corticospinal responses"
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Shafieian, Mehdi, and Kurosh Darvish. "Viscoelastic Properties of Injured and Uninjured Rat Brain Tissue." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176055.
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In this study, changes in the viscoelastic material properties of brain tissue due to traumatic diffuse axonal injury (DAI) were investigated. The impact acceleration model was used to generate DAI in rat brain stem. The viscoelastic material properties of brain tissue along the corticospinal (CSpT) tract in the brain stem were characterized using an indentation technique and a quasilinear theory. The results show significant reduction in the elastic response of brain tissue due to injury. In regions with significantly more DAI, larger changes in the elastic shear modulus and relaxation function were observed. These findings can improve the injury predictability of computational models of brain injury.
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Darvish, Kurosh, and James Stone. "Changes in Viscoelastic Properties of Brain Tissue Due to Traumatic Injury." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60849.
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In this study, changes in viscoelastic material properties of brain tissue due to traumatic axonal injury (TAI) were investigated. The impact acceleration model was used to generate diffuse axonal injury in rat brain. TAI in the corticospinal (CSpT) tract in the brain stem was quantified using amyloid precursor protein immunostaining. Material properties along the CSpT were determined using an indentation technique. The results showed that the number of injured axons at the pyramidal decussation (PDx) was approximated 10 times higher than in the ponto-medullary junction (PmJ). The instantaneous elastic response was reduced approximately 70% at PDx compared to 40% at PmJ and the relaxation was uniformly reduced approximately 30%, which were attributed to the effect of injury on tissue properties. Application of a visco-elastic-plastic model that changes due to TAI can significantly alter the results of computational models of brain injury.