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1.
Spine J ; 20(2): 191-198, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31479780

RESUMO

BACKGROUND CONTEXT: Motor evoked potentials (MEPs) have excellent sensitivity for monitoring the functional integrity of the lateral corticospinal tract of the spinal cord. The sensitivity for nerve root function, however, is not as well established; consequently, MEPs are often not utilized for posterior extradural spine procedures distal to the conus. Spontaneous electromyography (sEMG) and somatosensory evoked potentials (SSEPs) are often included for these procedures, but their limited sensitivity has been well documented. Given the risk of motor nerve root injuries during spine procedures, and specifically increased vulnerability of the L4 and L5 nerves, the sensitivity of MEPs was evaluated for diagnostic accuracy and therapeutic impact. PURPOSE: To determine the diagnostic sensitivity of MEPs during lumbosacral spine procedures and the potential therapeutic impact of the resolution of MEP alerts. STUDY DESIGN: A total of 4,386 posterior extradural lumbosacral spine procedures utilizing multimodality intraoperative neuromonitoring (IONM) with sEMG, SSEPs, and MEPs were abstracted from a multi-institutional database. All cases took place between October 2015 and October 2017. No external funding was provided. OUTCOME MEASURES: Sensitivity and specificity, as well as positive and negative likelihood ratios for new postoperative neurologic deficits were calculated for each modality individually as well as when combined (multimodality). PATIENT SAMPLE: Age 18 and older METHODS: Data entered in the electronic medical record were analyzed. Alerts to sEMG activity, decreases in SSEP amplitude, or decreases in MEP amplitude were documented as well as the status of the alerts at closure: resolved or unresolved. The presence of an sEMG alert or an unresolved MEP or SSEP alert at closure was considered a positive diagnostic result, and these results were assessed relative to presence of new immediate onset neurologic deficits as documented in the electronic record. RESULTS: The sensitivity and specificity of multimodality IONM for new immediate-onset lower extremity motor deficits were 100.0% (95% confidence interval: [64.6, 100.0]) and 92.2% (91.1, 93.1), respectively. Looking at the modalities in isolation, the sensitivity of MEPs was considerably better than either lower extremity sEMG or posterior tibial nerve SSEPs: 100.0% (78.5, 100.0) versus just 14.3% (4.0, 39.9) and 28.6% (8.2, 64.1), respectively. Surprisingly, the specificity of lower extremity MEPs was better than sEMG, 97.9% (97.5, 98.3) versus 95.4% (94.7, 96.0) (χ2=43.0, p<.001). The specificity of lower extremity SSEPs was 99.0% (98.5, 99.3). Only 4.4% of all procedures had a lower extremity MEP alert. There were 14 significant new nerve root injuries and all 14 had unresolved MEPs at closure. Total 85.7% of those nerve root injuries were dorsiflexion foot drop injuries and all had unresolved tibialis anterior MEP alerts. Although the overall rate of nerve root injuries was 0.32% (14/4,386), the rate for procedures with unresolved isolated tibialis anterior MEP alerts was 44.4% (12/27). The therapeutic impact is evident in the 2.0% of cases (87/4,386) with lower extremity MEP alerts that were able to be fully resolved by closure and for which the rate of injury was zero. CONCLUSIONS: The diagnostic accuracy of MEPs for anterior tibialis-related nerve root dysfunction supports the inclusion of this modality during routine posterior extradural lumbosacral procedures, especially when the L4 or L5 nerve roots are at risk. Moreover, therapeutic interventions that lead to the resolution of MEP alerts avert postoperative neurologic injuries.


Assuntos
Potencial Evocado Motor , Monitorização Neurofisiológica Intraoperatória/métodos , Região Lombossacral/cirurgia , Procedimentos Neurocirúrgicos/métodos , Traumatismos dos Nervos Periféricos/etiologia , Complicações Pós-Operatórias/etiologia , Adulto , Feminino , Humanos , Extremidade Inferior/fisiologia , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/efeitos adversos , Traumatismos dos Nervos Periféricos/prevenção & controle , Complicações Pós-Operatórias/prevenção & controle , Raízes Nervosas Espinhais/fisiologia
2.
Magn Reson Med Sci ; 19(2): 159-165, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31189790

RESUMO

We investigated the usefulness of diffusion tensor imaging using single-shot turbo spin-echo sequence (TSE-DTI) in detecting the responsible nerve root by multipoint measurements of fractional anisotropy (FA) values. Five patients with bilateral lumbar spinal stenosis showing unilateral neurological symptoms were examined using TSE-DTI. In the spinal canal, FA values in the symptomatic side were lower than those in the asymptomatic side. TSE-DTI using multipoint measurements of FA values can differentiate the responsible lumbar nerve root.


Assuntos
Imagem de Tensor de Difusão/métodos , Vértebras Lombares/diagnóstico por imagem , Raízes Nervosas Espinhais/diagnóstico por imagem , Humanos , Raízes Nervosas Espinhais/fisiologia , Estenose Espinal/diagnóstico por imagem
3.
Nat Commun ; 10(1): 4796, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641138

RESUMO

Interneurons (INs) coordinate motoneuron activity to generate appropriate patterns of muscle contractions, providing animals with the ability to adjust their body posture and to move over a range of speeds. In Drosophila larvae several IN subtypes have been morphologically described and their function well documented. However, the general lack of molecular characterization of those INs prevents the identification of evolutionary counterparts in other animals, limiting our understanding of the principles underlying neuronal circuit organization and function. Here we characterize a restricted subset of neurons in the nerve cord expressing the Maf transcription factor Traffic Jam (TJ). We found that TJ+ neurons are highly diverse and selective activation of these different subtypes disrupts larval body posture and induces specific locomotor behaviors. Finally, we show that a small subset of TJ+ GABAergic INs, singled out by the expression of a unique transcription factors code, controls larval crawling speed.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/fisiologia , Interneurônios/fisiologia , Fatores de Transcrição Maf Maior/metabolismo , Atividade Motora/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Animais , Animais Geneticamente Modificados , Drosophila/embriologia , Proteínas de Drosophila/genética , Embrião não Mamífero/fisiologia , Regulação da Expressão Gênica , Inativação Gênica , Larva/fisiologia , Locomoção/fisiologia , Fatores de Transcrição Maf Maior/genética , Proteínas Proto-Oncogênicas/genética , Raízes Nervosas Espinhais/fisiologia , Ácido gama-Aminobutírico/metabolismo
4.
PLoS Biol ; 17(9): e3000447, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31513565

RESUMO

In the mouse spinal cord, V1 interneurons are a heterogeneous population of inhibitory spinal interneurons that have been implicated in regulating the frequency of the locomotor rhythm and in organizing flexor and extensor alternation. By introducing archaerhodopsin into engrailed-1-positive neurons, we demonstrate that the function of V1 neurons in locomotor-like activity is more complex than previously thought. In the whole cord, V1 hyperpolarization increased the rhythmic synaptic drive to flexor and extensor motoneurons, increased the spiking in each cycle, and slowed the locomotor-like rhythm. In the hemicord, V1 hyperpolarization accelerated the rhythm after an initial period of tonic activity, implying that a subset of V1 neurons are active in the hemicord, which was confirmed by calcium imaging. Hyperpolarizing V1 neurons resulted in an equalization of the duty cycle in flexor and extensors from an asymmetrical pattern in control recordings in which the extensor bursts were longer than the flexor bursts. Our results suggest that V1 interneurons are composed of several subsets with different functional roles. Furthermore, during V1 hyperpolarization, the default state of the locomotor central pattern generator (CPG) is symmetrical, with antagonist motoneurons each firing with an approximately 50% duty cycle. We hypothesize that one function of the V1 population is to set the burst durations of muscles to be appropriate to their biomechanical function and to adapt to the environmental demands, such as changes in locomotor speed.


Assuntos
Geradores de Padrão Central , Células de Renshaw/fisiologia , Medula Espinal/fisiologia , Animais , Animais Recém-Nascidos , Proteínas Arqueais , Proteínas de Homeodomínio/metabolismo , Técnicas In Vitro , Locomoção , Camundongos , Raízes Nervosas Espinhais/fisiologia
5.
Neurogastroenterol Motil ; 31(12): e13709, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31452314

RESUMO

BACKGROUND: The rat has served usefully as a model for fecal incontinence and exploration of the mechanism of action of sacral neuromodulation. However, there is a gap in knowledge concerning representation(s) on the primary sensory cortex of this anatomical region. METHODS: Multi-electrode array (32 channels) and intrinsic optical signal (IOS) processing were used to map cortical activation sites following anorectal electrical stimulation in the rat. A simple method for expanding a 32-electrode array to a virtual 2700 array was refined. KEY RESULTS: The IOS method identified activation of parietal cortex following anorectal or first sacral nerve root (S1) stimulation; however, the signal was poorly localized and large spontaneous vasomotion was observed in pial vessels. In contrast, the resulting high-density maps showed two anatomically distinct cortical activation sites to anorectal stimulation. CONCLUSIONS & INFERENCES: There are two distinct sites of activation on the parietal cortex following anorectal stimulation in the rat. The implications for sacral neuromodulation as a therapy for fecal incontinence are discussed.


Assuntos
Canal Anal/inervação , Mapeamento Encefálico/métodos , Potenciais Somatossensoriais Evocados , Ratos/anatomia & histologia , Reto/inervação , Córtex Somatossensorial/fisiologia , Vias Aferentes/anatomia & histologia , Animais , Estimulação Elétrica , Eletrodos , Feminino , Pia-Máter/irrigação sanguínea , Ratos Wistar , Raízes Nervosas Espinhais/anatomia & histologia , Raízes Nervosas Espinhais/fisiologia , Sistema Vasomotor/anatomia & histologia , Sistema Vasomotor/fisiologia
6.
Brain Res Bull ; 152: 212-224, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31351157

RESUMO

Spinal dorsal roots can be affected by a wide range of lesions, leading to a significant loss of proprioceptive information transmission and greatly affecting motor behavior. In this context, the reimplantation of lesioned roots with platelet-rich plasma (PRP) may allow nerve regeneration. Therefore, the present study evaluated sensorimotor improvement following dorsal root rhizotomy and repair with PRP. For this purpose, female Lewis rats were subjected to unilateral rhizotomy (RZ) of the L4-L6 dorsal roots and divided into the following groups: (1) the unlesioned control group; (2) the group that underwent rhizotomy (RZ) without repair; and (3) the group that underwent RZ followed by root repair with PRP. PRP was obtained from human blood and characterized regarding platelet concentration, integrity, and viability. Reflex arc recovery was evaluated weekly for eight weeks by the electronic von Frey method. The spinal cords were processed 1 week postlesion to evaluate the in vivo gene expression of TNFα, TGF-ß, BDNF, GDNF, VEGF, NGF, IL-4, IL-6, IL-13 by qRT-PCR and eight weeks postlesion to evaluate changes in the glial response (GFAP and Iba-1) and excitatory synaptic circuits (VGLUT1) by immunofluorescence. The results indicated that PRP therapy partially restores the paw withdrawal reflex over time, indicating the reentry of primary afferents from the dorsal root ganglia into the spinal cord without exacerbating glial reactivity. Additionally, the analysis of mRNA levels showed that PRP therapy has immunomodulatory properties. Overall, the present data suggest that the repair of dorsal roots with PRP may be considered a promising approach to improve sensorimotor recovery following dorsal rhizotomy.


Assuntos
Plasma Rico em Plaquetas/metabolismo , Traumatismos da Medula Espinal/terapia , Raízes Nervosas Espinhais/fisiologia , Animais , Axônios , Feminino , Gânglios Espinais/metabolismo , Fatores de Crescimento Neural/metabolismo , Neuroglia/metabolismo , Neuroglia/fisiologia , Ratos , Ratos Endogâmicos Lew , Recuperação de Função Fisiológica/fisiologia , Reflexo/fisiologia , Rizotomia/métodos , Medula Espinal/metabolismo , Regeneração da Medula Espinal , Raízes Nervosas Espinhais/lesões
7.
Proc Natl Acad Sci U S A ; 116(30): 15272-15281, 2019 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-31296565

RESUMO

As animals forage for food and water or evade predators, they must rapidly decide what visual features in the environment deserve attention. In vertebrates, this visuomotor computation is implemented within the neural circuits of the optic tectum (superior colliculus in mammals). However, the mechanisms by which tectum decides whether to approach or evade remain unclear, and also which neural mechanisms underlie this behavioral choice. To address this problem, we used an eye-brain-spinal cord preparation to evaluate how the lamprey responds to visual inputs with distinct stimulus-dependent motor patterns. Using ventral root activity as a behavioral readout, we classified 2 main types of fictive motor responses: (i) a unilateral burst response corresponding to orientation of the head toward slowly expanding or moving stimuli, particularly within the anterior visual field, and (ii) a unilateral or bilateral burst response triggering fictive avoidance in response to rapidly expanding looming stimuli or moving bars. A selective pharmacological blockade revealed that the brainstem-projecting neurons in the deep layer of the tectum in interaction with local inhibitory interneurons are responsible for selecting between these 2 visually triggered motor actions conveyed through downstream reticulospinal circuits. We suggest that these visual decision-making circuits had evolved in the common ancestor of vertebrates and have been conserved throughout vertebrate phylogeny.


Assuntos
Comportamento de Escolha/fisiologia , Reação de Fuga/fisiologia , Vias Neurais/fisiologia , Orientação Espacial/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Colículos Superiores/fisiologia , Animais , Mapeamento Encefálico , Tronco Encefálico/anatomia & histologia , Tronco Encefálico/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Olho/anatomia & histologia , Interneurônios/citologia , Interneurônios/fisiologia , Lampreias/anatomia & histologia , Lampreias/fisiologia , Atividade Motora/fisiologia , Vias Neurais/anatomia & histologia , Medula Espinal/anatomia & histologia , Medula Espinal/fisiologia , Raízes Nervosas Espinhais/anatomia & histologia , Raízes Nervosas Espinhais/fisiologia , Colículos Superiores/anatomia & histologia
8.
Eur J Neurosci ; 50(7): 3101-3107, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31111553

RESUMO

We report evidence that ephaptic interactions may occur between intact mammalian myelinated nerve fibres and not only between demyelinated or damaged mammalian nerve fibres or nerve cells as analysed in previous studies. The ephaptic interactions were investigated between nerve fibres traversing the lumbar dorsal roots and between bundles of fibres in the sciatic nerve in anaesthetized rats in vivo. The interactions were estimated by comparing the excitability of nerve fibres originating from one of the hindlimb nerves (peroneal or sural) under control conditions and when the stimulation of these fibres was combined with stimulation of another nerve (tibial). An increase in nerve volleys recorded from group I muscle afferents in the peroneal nerve and of the fastest skin afferents in the sural nerve was used as a measure of the increase in the excitability. The excitability of these fibres was increased during a fraction of a millisecond, coinciding with the period of passage of nerve impulses evoked by the conditioning stimulation of the tibial nerve. The degree of the increase was comparable to the increases in the excitability evoked by 1-2 min lasting fibre polarization. Ephaptic interactions were found to be more potent and with longer lasting after-effects within the dorsal roots than within the sciatic nerve. We postulate that ephaptic interactions may result in the synchronization of information forwarded via neighbouring afferent nerve fibres prior to their entry into the spinal cord and thereby securing the propagation of nerve impulses across branching points within the spinal grey matter.


Assuntos
Potenciais de Ação , Fibras Nervosas Mielinizadas/fisiologia , Nervo Isquiático/fisiologia , Raízes Nervosas Espinhais/fisiologia , Animais , Fenômenos Eletrofisiológicos , Ratos Wistar , Medula Espinal
9.
PLoS One ; 14(4): e0215036, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30970000

RESUMO

OBJECTIVE: We aimed to refine electroneurogram techniques for monitoring hypogastric nerve activity during bladder filling, and then examined nerve activity in normal intact versus acutely decentralized bladders. METHODS: Effects of electrical stimulation of hypogastric nerves or lumbar ventral roots on detrusor pressure were examined, as were effects of isoflurane versus propofol anesthetics on hypogastric nerve stimulation evoked pressure. Hypogastric nerve activity was then recorded using custom-made bipolar cuff electrodes during bladder filling before and after its transection between the spinal cord and electrode to eliminate efferent nerve signals. RESULTS: Electrical stimulation of hypogastric nerves evoked low amplitude detrusor pressures that did not differ between the two anesthetics. Upper lumbar (L2) ventral root stimulation evoked detrusor pressures were suppressed, yet not eliminated, after transection of hypogastric nerves and all spinal roots below L5. Afferent and efferent hypogastric nerve activity did not change with bladder filling in neuronally intact bladders yet decreased in decentralized bladders. No change in afferent activity was observed during bladder filling in either intact or decentralized bladders. CONCLUSIONS: These findings indicate that a more complete decentralized bladder model should include transection of lumbosacral spinal roots innervating the bladder as well as hypogastric nerves. These refined electroneurogram recording methods may be suitable for evaluating the effectiveness of nerve transfer surgeries for bladder reinnervation by monitoring sensory activity in the transferred nerve.


Assuntos
Estimulação Elétrica , Raízes Nervosas Espinhais/fisiologia , Sistema Nervoso Simpático/fisiologia , Bexiga Urinária/fisiologia , Animais , Cães , Potenciais Evocados , Isoflurano/farmacologia , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/fisiologia , Neurônios Eferentes/efeitos dos fármacos , Neurônios Eferentes/fisiologia , Propofol/farmacologia , Raízes Nervosas Espinhais/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos
10.
J Neurophysiol ; 121(5): 1672-1679, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30840527

RESUMO

Transcutaneous and epidural electrical spinal cord stimulation techniques are becoming more valuable as electrophysiological and clinical tools. Recently, remarkable recovery of the upper limb sensorimotor function during cervical spinal stimulation was demonstrated. In the present study, we sought to elucidate the neural mechanisms underlying the effects of transcutaneous spinal cord stimulation (tSCS) of the cervical spine. We hypothesized that cervical tSCS can be used to selectively activate the sensory route entering the spinal cord and transsynaptically converge on upper limb motor pools. To test this hypothesis, we applied cervical tSCS using paired stimuli (homosynaptic depression) and during passive muscle stretching of the wrist flexor (presynaptic inhibition via Ia afferents), voluntary hand muscle contraction (descending facilitation of motoneuron pool), and muscle-tendon vibration of the wrist (presynaptic inhibition via afferent occlusion). Our results demonstrate significant inhibition of the second evoked response during paired stimulus delivery, inhibition of responses during passive muscle stretching and muscle-tendon vibration, and facilitation during voluntary muscle contraction, which share similarities with responses evoked during lumbosacral tSCS. These results indicate that the route of the stimulation current transmission passes via afferents in the dorsal roots through the spinal cord to activate the motor pools and potentially interneuronal networks projecting to upper limb muscles. Using a novel stimulation paradigm, our study is the first to present evidence of the sensory neuronal pathway of the cervical tSCS propagation. Overall, our work demonstrates the utility and sensitivity of cervical tSCS to engage the sensory pathway projecting to the upper limbs. NEW & NOTEWORTHY Despite therapeutic effects that have been demonstrated previously using noninvasive cervical spinal stimulation, it has been unclear whether, and to what degree, the stimulation can activate the sensory afferent system. Our study presents evidence that cervical transcutaneous spinal cord stimulation can engage the sensory pathways and transsynaptically converge on motor pools projecting to upper limb muscles, demonstrating the utility and sensitivity of cervical spinal stimulation for electrophysiological assessments and neurorehabilitation.


Assuntos
Reflexo , Estimulação da Medula Espinal/métodos , Medula Espinal/fisiologia , Adulto , Vértebras Cervicais/fisiologia , Humanos , Interneurônios/fisiologia , Contração Muscular , Músculo Esquelético/fisiologia , Neurônios Aferentes/fisiologia , Raízes Nervosas Espinhais/fisiologia , Potenciais Sinápticos , Punho/fisiologia
11.
Neuromodulation ; 22(6): 703-708, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30786100

RESUMO

OBJECTIVES: High-frequency (kHz) stimulation of preganglionic pelvic nerve afferents can inhibit voiding in both anesthetized and conscious rats. The afferents travel via the S1 sacral nerve root, which is easier to access than the distal pelvic nerve fibers within the abdominal cavity. We therefore investigated whether voiding could be inhibited by high-frequency stimulation at S1 and how this compared to distal pelvic nerve stimulation. METHODS: Urethane-anesthetized rats were instrumented to record bladder pressure and abdominal wall electromyogram and to stimulate the distal preganglionic pelvic nerve bundle and S1 sacral root. Saline was infused continuously into the bladder to evoke repeated voiding. Stimulation was initiated within 1-2 sec of the onset of the steep rise in bladder pressure signaling an imminent void. RESULTS: In six rats, stimulation of the distal pelvic nerve bundle (1-3 kHz sinusoidal waveform 1 mA, 60 sec) supressed the occurrence of an imminent void. Voiding resumed within 70 ± 13.0 sec (mean ± SEM) of stopping stimulation. Stimulation (using the same parameters) of the S1 root at the level of the sacral foramen suppressed voiding for the entire stimulation period in three rats and deferred voiding for 35-56 sec (mean 44.0 ± 3.2 sec) in the remaining three. Stimulation at either site when the bladder was approximately half full, as estimated from previous intervoid intervals, had no effect on voiding. CONCLUSIONS: This preliminary study provides proof-of-concept for the sacral root as an accessible target for high-frequency stimulation that may be developed as an "on demand" neuromodulation paradigm to suppress unwanted urinary voids. CONFLICT OF INTEREST: The authors reported no conflict of interest.


Assuntos
Anestésicos Intravenosos/administração & dosagem , Terapia por Estimulação Elétrica/métodos , Sacro/inervação , Sacro/fisiologia , Raízes Nervosas Espinhais/fisiologia , Micção/fisiologia , Animais , Feminino , Ratos , Ratos Wistar , Sacro/cirurgia , Raízes Nervosas Espinhais/cirurgia , Uretana/administração & dosagem
12.
J Tradit Chin Med ; 39(5): 685-691, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-32186118

RESUMO

OBJECTIVE: To investigate how electroacupuncture (EA) at Zusanli (ST 36) with varying intensities of stimulation affects dorsal root nerve signals in normal rats. METHODS: Adult female Wistar rats were examined after drug-induced anesthesia and isolation of the L4 dorsal root associated with the Zusanli (ST 36) acupoint, using bipolar platinum electrodes. We applied EA at Zusanli (ST 36) with a continuous wave waveform for 1 min, and recorded action potentials in the L4 spinal cord dorsal root nerve with a frequency of 5 Hz and various current intensity levels (approximately 1-4 mA). In addition, we tested EA with a frequency of 15 Hz and current intensity of 1-4 mA. The L4 spinal cord dorsal nerve bundle action potentials were measured for 1 min of EA. To analyze the discharge frequency, we used the maximum Lyapunov exponent and Lempel-Ziv (LZ) complexity. RESULTS: At a fixed frequency, with increasing intensity of EA, dorsal root nerve filament discharge frequency revealed an initial increase, followed by a decreasing trend. A stimulation intensity of 3 mA induced a significantly greater discharge frequency, compared with stimulation intensities of 2 and 4 mA. EA stimulation evoked neuroelectric signals with chaotic characteristics. Increased intensity led to an initial increase in LZ complexity which then decreased, with a stimulation strength of 3 mA inducing the highest level of LZ complexity. CONCLUSION: EA of different intensities can induce nerve action potential encoding with different features.


Assuntos
Eletroacupuntura , Raízes Nervosas Espinhais/fisiologia , Animais , Feminino , Ratos , Ratos Sprague-Dawley , Ratos Wistar
13.
J Physiol Sci ; 69(2): 253-262, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30324557

RESUMO

Ia excitation and recurrent inhibition are basic neuronal circuits in motor control in hind limb. Renshaw cells receive synaptic inputs from axon collaterals of motoneurons and inhibit motoneurons and Ia inhibitory interneurons. It is important to know properties of Ia excitation and recurrent inhibition of trunk muscle such as abdominal muscles. The abdominal muscles have many roles and change those roles for different kind of functions. Intracellular recordings were obtained from the abdominal motoneurons of the upper lumbar segments in cats anesthetized. First, dorsal roots were left intact, and sensory and motor axons were electrically stimulated. Ia excitatory post-synaptic potentials were elicited in five of eight motoneurons at same segment stimulated. Second, dorsal roots were sectioned, and motor axons were electrically stimulated. Recurrent inhibitory post-synaptic potentials were elicited in one of 11 abdominal motoneurons. Renshaw cells extracellularly fired high-frequency bursts at short latency and at same segment stimulated.


Assuntos
Cavidade Abdominal/fisiologia , Fenômenos Eletrofisiológicos/fisiologia , Potenciais da Membrana/fisiologia , Neurônios Motores/fisiologia , Animais , Axônios/fisiologia , Gatos , Estimulação Elétrica/métodos , Membro Posterior/fisiologia , Músculo Esquelético/fisiologia , Raízes Nervosas Espinhais/fisiologia , Sinapses/fisiologia
14.
Neuroscience ; 397: 1-11, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30500613

RESUMO

The inspiratory motor activities are greater in the intercostal muscles positioned at more rostral thoracic segments. This rostro-caudal gradient of the thoracic inspiratory motor activity is thought to be generated by the spinal interneurons. To clarify the involvement of the inhibitory thoracic interneurons in this rostro-caudal gradient, we examined the effects of 10 µM strychnine, an antagonist of glycine and GABAA receptors, applied to the neonatal rat thoracic spinal cord. The respiratory-related interneuron activities were optically recorded from thoracic segments in the isolated neonatal rat brainstem-spinal cord preparations stained with voltage-sensitive dye, and the electrical inspiratory motor activities were obtained from the third and eleventh thoracic ventral roots (T3VR, T11VR). Although strychnine caused seizure-like activities in all of the ventral roots recorded, the inspiratory motor activities continued. The inspiratory optical signals in the rostral thoracic segments (T2-T5) were significantly larger than those in the caudal thoracic segments (T9-T11) regardless of the existence of strychnine. Similarly, the percent ratio of the amplitude of the inspiratory electrical activity in the T3VR under control and strychnine was significantly larger than that in the T11VR regardless of the existence of strychnine. Strychnine significantly increased the inspiratory activity in both the T3VR and T11VR. These results suggest that the glycinergic and GABAergic inhibitory interneurons are not essential to generate the rostro-caudal gradient in the neonatal rat thoracic inspiratory motor outputs, but these interneurons are likely to play a role in the inhibitory control of inspiratory motor output.


Assuntos
Inalação/fisiologia , Interneurônios/fisiologia , Movimento/fisiologia , Inibição Neural/fisiologia , Músculos Respiratórios/fisiologia , Raízes Nervosas Espinhais/fisiologia , Animais , Animais Recém-Nascidos , Tronco Encefálico/efeitos dos fármacos , Tronco Encefálico/fisiologia , Glicina/metabolismo , Inalação/efeitos dos fármacos , Interneurônios/efeitos dos fármacos , Movimento/efeitos dos fármacos , Inibição Neural/efeitos dos fármacos , Neurotransmissores/farmacologia , Ratos Wistar , Receptores de GABA-A/metabolismo , Receptores da Glicina/antagonistas & inibidores , Receptores da Glicina/metabolismo , Músculos Respiratórios/efeitos dos fármacos , Músculos Respiratórios/inervação , Convulsões/fisiopatologia , Raízes Nervosas Espinhais/efeitos dos fármacos , Estricnina/farmacologia , Vértebras Torácicas , Técnicas de Cultura de Tecidos , Imagens com Corantes Sensíveis à Voltagem , Ácido gama-Aminobutírico/metabolismo
15.
Assist Technol ; 31(1): 1-8, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-28960131

RESUMO

The objective of this article is to examine dynamic changes of ischial blood perfusion during sacral nerve root stimulation against surface functional electrical stimulation (FES). Fourteen adults with suprasacral spinal cord injury (SCI) were recruited. The gluteal maximus was activated by surface FES or stimulating sacral nerve roots by functional magnetic stimulation (FMS) or a sacral anterior root stimulator implant (SARS). Ischial skin index of hemoglobin (IHB) and oxygenation (IOX) was measured.Skin blood perfusion was significantly higher during FMS than the baseline (IHB 1.05 ± 0.21 before vs.1.08 ± 0.02 during stimulation, p = 0.03; IOX 0.18 ± 0.21 before vs. 0.46 ± 0.30, p = 0.01 during stimulation). Similarly, when using the SARS implant, we also observed blood perfusion significantly increased (IHB 1.01 ± 0.02 before vs.1.07 ± 0.02 during stimulation, p = 0.003; IOX 0.79 ± 0.81 before vs. 2.2 ± 1.21 during stimulation, p = 0.036). Among four participants who completed both the FMS and FES studies, the magnitude of increase in both parameters was significantly higher during FMS. This study demonstrates sacral nerve root stimulation confer better benefit on blood perfusion than applying traditional FES in SCI population.


Assuntos
Estimulação Elétrica , Terapia de Campo Magnético , Pele/irrigação sanguínea , Traumatismos da Medula Espinal/terapia , Raízes Nervosas Espinhais/fisiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Lesão por Pressão/prevenção & controle , Fluxo Sanguíneo Regional/efeitos da radiação , Sacro/inervação , Traumatismos da Medula Espinal/fisiopatologia , Adulto Jovem
16.
Brain Behav ; 8(12): e01174, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30565875

RESUMO

INTRODUCTION: Contralateral cervical seventh nerve root (CC7) transfer has been widely applied for treatment of traumatic brachial plexus injury. The purpose of the study was to evaluate outcomes of patients with global brachial plexus avulsion (GBPA) after CC7 transfer and compare the recoveries of median nerve as the only recipient nerve and one of the multiple recipient nerves. METHODS: A retrospective review of 51 patients treated with CC7 transfers after GBPA was carried out. The British Medical Research Council (MRC) grading system and range of joint motion (ROM) were used for motor and sensory assessment. RESULTS: The effective rates of FCR were 57.7%, 45.5%, and 36.4% in CC7 transfer to median nerve (CC7-Md), CC7 transfer to median nerve and biceps branch (CC7-Md+Bic) and CC7 transfer to median nerve and triceps branch (CC7-Md+Tric) groups, respectively. There were no statistical differences no matter in FCR or FDS among groups. The effective rate in biceps had no significant difference with that in triceps. The effective sensory recovery rate was 65.4%, 54.5%, and 36.4% in CC7-Md, CC7-Md+Bic, and CC7-Md+Tric groups. There were no statistical differences in the sensory effective recovery rate among groups. All the ROMs were improved significantly after surgery. The improvement of ROM of elbow flexion after surgery in CC7-Md+Bic group was significantly larger than that of elbow extension after surgery in CC7-Md+Tric group (p = 0.047). CONCLUSIONS: The CC7 transfer contributed to the functional improvement of the hand and wrist for the patients with global brachial plexus avulsion. The whole CC7 could be used to repair more than one recipient nerve (including median nerve) without affecting the recovery of median nerve. When CC7 was used to repair two nerves, biceps branch might be preferred to choose as one recipient nerve rather than triceps branch.


Assuntos
Plexo Braquial/lesões , Transferência de Nervo/métodos , Adolescente , Adulto , Vértebras Cervicais/inervação , Feminino , Mãos/fisiologia , Humanos , Masculino , Nervo Mediano/fisiologia , Nervo Mediano/cirurgia , Pessoa de Meia-Idade , Músculo Esquelético/cirurgia , Estudos Retrospectivos , Raízes Nervosas Espinhais/fisiologia , Raízes Nervosas Espinhais/cirurgia , Transplantados , Resultado do Tratamento , Punho/fisiologia , Adulto Jovem
17.
IEEE Trans Neural Syst Rehabil Eng ; 26(11): 2165-2178, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30475704

RESUMO

Nearly all spinal cord injured (SCI) individuals lose bladder control and are prone to kidney complications if intermittent catheterization is not applied. Electrical stimulation of the sacral anterior roots with an implantable neuroprosthesis is one means to restore continence and control micturition. However, only a small percentage of the SCI population benefits from this solution because of its drawbacks, e.g., section of sacral posterior roots with loss of spared sensitivity. There has been renewed interest in spinal cord stimulation in recent years, but most studies have focused on locomotion and only few have reported the impact on visceral functions. Moreover, even though the lumbosacral spinal cord is the location of many pre-cabled neural networks (involved in locomotion, bladder, and bowel management), the functional selectivity of spinal stimulations has never been investigated in detail. Here, we present: 1) a methodology designed to study lumbosacral epispinal-intradural stimulation selectivity; 2) preliminary results assessing the impact of epispinal stimulation on bladder and bowel functions in two domestic pigs; and 3) a comparison of these visceral responses with abdominal and lower limb activities. Our experiments resulted in selective bladder and rectal responses, i.e., without hind paw responses, thus reaffirming the rehabilitation potential of spinal cord stimulation.


Assuntos
Região Lombossacral/fisiologia , Próteses Neurais , Estimulação da Medula Espinal/métodos , Animais , Dura-Máter/fisiologia , Eletromiografia , Trato Gastrointestinal/fisiologia , Rede Nervosa/fisiologia , Projetos Piloto , Reto/fisiologia , Medula Espinal/fisiologia , Traumatismos da Medula Espinal/reabilitação , Raízes Nervosas Espinhais/fisiologia , Suínos , Bexiga Urinária/fisiologia
18.
Nat Commun ; 9(1): 4390, 2018 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-30348941

RESUMO

To understand neural circuits that control limbs, one must measure their activity during behavior. Until now this goal has been challenging, because limb premotor and motor circuits have been largely inaccessible for large-scale recordings in intact, moving animals-a constraint that is true for both vertebrate and invertebrate models. Here, we introduce a method for 2-photon functional imaging from the ventral nerve cord (VNC) of behaving adult Drosophila melanogaster. We use this method to reveal patterns of activity across nerve cord populations during grooming and walking and to uncover the functional encoding of moonwalker ascending neurons (MANs), moonwalker descending neurons (MDNs), and a previously uncharacterized class of locomotion-associated A1 descending neurons. Finally, we develop a genetic reagent to destroy the indirect flight muscles and to facilitate experimental access to the VNC. Taken together, these approaches enable the direct investigation of circuits associated with complex limb movements.


Assuntos
Diagnóstico por Imagem/métodos , Raízes Nervosas Espinhais/fisiologia , Animais , Drosophila , Proteínas de Drosophila/metabolismo , Locomoção/fisiologia , Neurônios Motores/metabolismo , Neurônios Motores/fisiologia , Raízes Nervosas Espinhais/metabolismo
19.
Neuroscience ; 394: 44-59, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30342198

RESUMO

Locomotor patterns are mainly modulated by afferent feedback, but its actual contribution to spinal network activity during continuous passive limb training is still unexplored. To unveil this issue, we devised a robotic in vitro setup (Bipedal Induced Kinetic Exercise, BIKE) to induce passive pedaling, while simultaneously recording low-noise ventral and dorsal root (VR and DR) potentials in isolated neonatal rat spinal cords with hindlimbs attached. As a result, BIKE evoked rhythmic afferent volleys from DRs, reminiscent of pedaling speed. During BIKE, spontaneous VR activity remained unchanged, while a DR rhythmic component paired the pedaling pace. Moreover, BIKE onset rarely elicited brief episodes of fictive locomotion (FL) and, when trains of electrical pulses were simultaneously applied to a DR, it increased the amplitude, but not the number, of FL cycles. When BIKE was switched off after a 30-min training, the number of electrically induced FL oscillations was transitorily facilitated, without affecting VR reflexes or DR potentials. However, 90 min of BIKE no longer facilitated FL, but strongly depressed area of VR reflexes and stably increased antidromic DR discharges. Patch clamp recordings from single motoneurons after 90-min sessions indicated an increased frequency of both fast- and slow-decaying synaptic input to motoneurons. In conclusion, hindlimb rhythmic and alternated pedaling for different durations affects distinct dorsal and ventral spinal networks by modulating excitatory and inhibitory input to motoneurons. These results suggest defining new parameters for effective neurorehabilitation that better exploits spinal circuit activity.


Assuntos
Locomoção , Neurônios Aferentes/fisiologia , Robótica , Medula Espinal/fisiologia , Raízes Nervosas Espinhais/fisiologia , Vias Aferentes/fisiologia , Animais , Estimulação Elétrica , Membro Posterior/inervação , Membro Posterior/fisiologia , Neurônios Motores/fisiologia , Ratos Wistar
20.
Spine Deform ; 6(5): 627-630, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30122401

RESUMO

BACKGROUND: Transcranial motor evoked potential (TcMEP) is widely used intraoperatively to monitor spinal cord and nerve root function. To our knowledge, there is no report regarding TcMEP signal loss purely caused by patient positioning during the spinal procedure. PURPOSE: The objective of this article is to report an intraoperative TcMEP signal loss of a patient with fixed sagittal imbalance posture along with mild hip contractures. STUDY DESIGN: A retrospective case report. METHODS: A 57-year-old man had fixed sagittal imbalance and flexed hip contractures. For a reconstruction surgery of T10 to the sacrum/ilium and L5 pedicle subtraction osteotomy (PSO), he was put in a prone position on a Jackson table. In order to accommodate his fixed hip flexion contracture, thigh pads were not used and pillows were placed under his bilateral thighs for cushioning. TcMEPs were used to assess lumbar nerve root function. Ten minutes after incision, bilateral vastus medialis TcMEPs were lost during spine exposure whereas all other data remained normal at baseline. The bilateral lower extremities were repositioned, with the knees flexed into a sling position to increase hip flexion. Five minutes after repositioning, the bilateral vastus medialis TcMEPs gradually improved and maintained baseline amplitude during the remainder of the surgery. RESULTS: No muscle weakness was detected immediately after surgery. The patient was discharged day 6 postoperatively with markedly improved posture and alignment. CONCLUSION: Insufficient hip flexion in patients with fixed sagittal imbalance and hip flexion contractures may cause TcMEP signal changes in the quadriceps response. TcMEP monitoring of bilateral lower extremities is highly recommended for patients with sagittal imbalance and hip contractures, with consideration for lower extremity repositioning when data degradation does not correlate with the actual spinal procedure being performed.


Assuntos
Contratura de Quadril/cirurgia , Monitorização Neurofisiológica Intraoperatória/métodos , Raízes Nervosas Espinhais/fisiologia , Potencial Evocado Motor , Contratura de Quadril/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteotomia , Decúbito Ventral , Resultado do Tratamento
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