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1.
Neuroimage ; 228: 117702, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33385558

RESUMO

The development of the organization of the motor representation areas in children and adolescents is not well-known. This cross-sectional study aimed to provide an understanding for the development of the functional motor areas of the upper extremity muscles by studying healthy right-handed children (6-9 years, n = 10), preadolescents (10-12 years, n = 13), adolescents (15-17 years, n = 12), and adults (22-34 years, n = 12). The optimal representation site and resting motor threshold (rMT) for the abductor pollicis brevis (APB) were assessed in both hemispheres using navigated transcranial magnetic stimulation (nTMS). Motor mapping was performed at 110% of the rMT while recording the EMG of six upper limb muscles in the hand and forearm. The association between the motor map and manual dexterity (box and block test, BBT) was examined. The mapping was well-tolerated and feasible in all but the youngest participant whose rMT exceeded the maximum stimulator output. The centers-of-gravity (CoG) for individual muscles were scattered to the greatest extent in the group of preadolescents and centered and became more focused with age. In preadolescents, the CoGs in the left hemisphere were located more laterally, and they shifted medially with age. The proportion of hand compared to arm representation increased with age (p = 0.001); in the right hemisphere, this was associated with greater fine motor ability. Similarly, there was less overlap between hand and forearm muscles representations in children compared to adults (p<0.001). There was a posterior-anterior shift in the APB hotspot coordinate with age, and the APB coordinate in the left hemisphere exhibited a lateral to medial shift with age from adolescence to adulthood (p = 0.006). Our results contribute to the elucidation of the developmental course in the organization of the motor cortex and its associations with fine motor skills. It was shown that nTMS motor mapping in relaxed muscles is feasible in developmental studies in children older than seven years of age.


Assuntos
Mapeamento Encefálico/métodos , Antebraço/inervação , Mãos/inervação , Córtex Motor/crescimento & desenvolvimento , Músculo Esquelético/inervação , Adolescente , Adulto , Criança , Estudos Transversais , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Estimulação Magnética Transcraniana/métodos , Adulto Jovem
2.
Nat Commun ; 12(1): 435, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469022

RESUMO

Epidural electrical stimulation (EES) of lumbosacral sensorimotor circuits improves leg motor control in animals and humans with spinal cord injury (SCI). Upper-limb motor control involves similar circuits, located in the cervical spinal cord, suggesting that EES could also improve arm and hand movements after quadriplegia. However, the ability of cervical EES to selectively modulate specific upper-limb motor nuclei remains unclear. Here, we combined a computational model of the cervical spinal cord with experiments in macaque monkeys to explore the mechanisms of upper-limb motoneuron recruitment with EES and characterize the selectivity of cervical interfaces. We show that lateral electrodes produce a segmental recruitment of arm motoneurons mediated by the direct activation of sensory afferents, and that muscle responses to EES are modulated during movement. Intraoperative recordings suggested similar properties in humans at rest. These modelling and experimental results can be applied for the development of neurotechnologies designed for the improvement of arm and hand control in humans with quadriplegia.


Assuntos
Medula Cervical/fisiopatologia , Neurônios Motores/fisiologia , Quadriplegia/terapia , Recrutamento Neurofisiológico/fisiologia , Traumatismos da Medula Espinal/terapia , Estimulação da Medula Espinal/métodos , Vias Aferentes/fisiopatologia , Animais , Medula Cervical/citologia , Medula Cervical/diagnóstico por imagem , Medula Cervical/lesões , Simulação por Computador , Modelos Animais de Doenças , Eletrodos Implantados , Espaço Epidural , Feminino , Gânglios Espinais/citologia , Gânglios Espinais/diagnóstico por imagem , Gânglios Espinais/fisiopatologia , Humanos , Macaca fascicularis , Imagem por Ressonância Magnética , Masculino , Modelos Neurológicos , Músculo Esquelético/inervação , Quadriplegia/etiologia , Quadriplegia/fisiopatologia , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/diagnóstico , Traumatismos da Medula Espinal/fisiopatologia , Estimulação da Medula Espinal/instrumentação , Extremidade Superior/inervação
3.
BMJ Case Rep ; 13(12)2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33370939

RESUMO

Slowly progressing unilateral upper limb weakness in a previously healthy child can occur due to number of causes which requires a thorough history, physical examination followed by radiological examination, electromyography and so on. Among the various aetiologies, a rare condition such as Hirayama disease is one of the differentials to be considered. There has been a wealth of literature reported on this disease and our case is a learning lesson for all paediatricians to be aware of Hirayama disease and its current concepts.


Assuntos
Braquetes , Debilidade Muscular/etiologia , Medula Espinal/patologia , Atrofias Musculares Espinais da Infância/diagnóstico , Adolescente , Vértebras Cervicais/diagnóstico por imagem , Diagnóstico Diferencial , Eletromiografia , Humanos , Imagem por Ressonância Magnética , Masculino , Debilidade Muscular/diagnóstico , Debilidade Muscular/terapia , Músculo Esquelético/inervação , Músculo Esquelético/fisiopatologia , Pescoço , Medula Espinal/diagnóstico por imagem , Atrofias Musculares Espinais da Infância/complicações , Atrofias Musculares Espinais da Infância/terapia , Extremidade Superior/inervação
4.
J Stroke Cerebrovasc Dis ; 29(10): 105163, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32912561

RESUMO

Acute pure motor hemiparesis can occur due to a vascular insult along the cortico spinal pathway. Rarely such a stroke can occur as a result of involvement of the pyramids located on the ventral aspect of the medulla. Neurological localization can be difficult in such strokes and moreover they can also pose imaging challenges since they are missed on the CT scans. So far only 4 such cases have been reported in literature. Here we present two cases of pure motor strokes caused by infarction of the medullary pyramids. We have described the anatomical correlates of the symptoms and signs and also highlight the importance of MRI in picking up these rare strokes.


Assuntos
Infartos do Tronco Encefálico/complicações , Infarto Cerebral/complicações , Bulbo/irrigação sanguínea , Músculo Esquelético/inervação , Paresia/etiologia , Tratos Piramidais/irrigação sanguínea , Idoso , Infartos do Tronco Encefálico/diagnóstico por imagem , Infartos do Tronco Encefálico/fisiopatologia , Infarto Cerebral/diagnóstico por imagem , Infarto Cerebral/fisiopatologia , Avaliação da Deficiência , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neurônios Motores , Paresia/diagnóstico , Paresia/fisiopatologia , Tomografia Computadorizada por Raios X
5.
J Stroke Cerebrovasc Dis ; 29(10): 105174, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32912567

RESUMO

Stroke survivors often face difficulty in community ambulation though they attain steady-state walking in clinical setups. Compliance and unpredictability of the environment may alter the muscle activity and challenge the individual's gait. Successful reintegration into the community requires gait assessment and training in a real-life challenging environment. Little is known about the assessment and training of gait in the community environment under challenging mobility dimensions. Hence, we aimed to study the changes that real-life environmental dimensions have on the activity of selected muscles in hemiparetic lower limb and gait velocity in stroke survivors. METHODS: An observational cross-sectional study was conducted on 16 ambulatory stroke survivors to assess the hemiparetic lower limb muscle activity during walking in real-life environmental dimensions. Participants were made to walk in the community on a walkway consisting of even surface, ramp, stairs, uneven terrain and obstacles. They were also made to manoeuvre through traffic and pick a load while walking for a distance in the walkway. Muscle activity of Rectus Femoris, Biceps Femoris, Gastrocnemius Medialis and Tibialis Anterior of the paretic lower limb were continuously recorded while walking using wireless surface electromyography. Gait velocity for the entire walkway and level of perceived difficulty while walking in different dimensions were also measured. Paired t-test was used to compare the percentage Maximum Voluntary Contraction (%MVC) of lower limb muscles between even surface and real-life environment dimensions while walking. One sample t-test was used to compare the gait velocity in real-life dimensions versus gait velocity in even surface measured in an earlier study. RESULTS: There was a significant reduction (p < 0.01) in the activity of all four hemiparetic lower limb muscles while walking under the influence of real-life environmental dimensions compared to even surface. Gait velocity (0.33 ± 0.17 m/s) was significantly lower than that is essential to be a community ambulator. The level of perceived difficulty across all dimensions was reported qualitatively with the highest difficulty reported during stair and obstacle clearance. CONCLUSION: Real-life environmental dimensions lead to the reduction of paretic lower limb muscle activities and gait velocity during walking in community-dwelling stroke survivors. Stroke survivors perceived more difficulty while walking in real-life environment dimensions particularly while negotiating stairs and obstacles. SIGNIFICANCE: Knowledge about the influence of real-life environmental dimensions will help the clinicians to target rehabilitation methods to improve walking adaptability.


Assuntos
Meio Ambiente , Contração Muscular , Músculo Esquelético/inervação , Paresia/fisiopatologia , Acidente Vascular Cerebral/complicações , Velocidade de Caminhada , Atividades Cotidianas , Adulto , Idoso , Estudos Transversais , Eletromiografia , Análise da Marcha , Humanos , Extremidade Inferior , Masculino , Pessoa de Meia-Idade , Limitação da Mobilidade , Paresia/diagnóstico , Paresia/etiologia , Paresia/reabilitação , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Reabilitação do Acidente Vascular Cerebral
6.
Sports Biomech ; 19(6): 723-737, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32942954

RESUMO

The aim of this study was to understand if and how surface-induced vibrations and road bike damping affect short-term neuromuscular performance in cycling. Thirty cyclists (mass 75.9 ± 8.9 kg, height 1.82 ± 0.05 m, Vo2max 63.0 ± 6.8 ml/min/kg) performed steady-state and maximum effort tests with and without vibration exposure (front dropout: 44 Hz, 4.1 mm; rear dropout: 38 Hz, 3.5 mm) on a damped and a nondamped bike. Transmitted accelerations to the musculoskeletal system, activation of lower extremity muscles (gast. med., soleus, vast. med., rec. fem.) and upper body muscles (erec. spinae, deltoideus, tric. brachii), oxygen uptake, heart rate and crank power output were measured. The main findings indicate a transmission of vibration to the whole body, but since no major propulsive muscles increase their activation with vibration, the systemic energy demand increases only marginally with vibration. Damping reduces vibrations at the upper body, which indicates an increase in comfort, but has no effect on the vibration transfer to the lower extremities. Therefore, road bike damping does not affect neuromuscular response of the propulsive muscle groups and energy demand. Consequently, short-term power output does not increase with damping.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Meio Ambiente , Músculo Esquelético/fisiologia , Vibração , Aceleração , Fenômenos Biomecânicos , Estudos Transversais , Frequência Cardíaca/fisiologia , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/inervação , Consumo de Oxigênio/fisiologia , Tronco/fisiologia , Extremidade Superior/fisiologia
7.
Sports Health ; 12(6): 579-586, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866081

RESUMO

CONTEXT: Distinct from the muscle atrophy that develops from inactivity or disuse, atrophy that occurs after traumatic joint injury continues despite the patient being actively engaged in exercise. Recognizing the multitude of factors and cascade of events that are present and negatively influence the regulation of muscle mass after traumatic joint injury will likely enable clinicians to design more effective treatment strategies. To provide sports medicine practitioners with the best strategies to optimize muscle mass, the purpose of this clinical review is to discuss the predominant mechanisms that control muscle atrophy for disuse and posttraumatic scenarios, and to highlight how they differ. EVIDENCE ACQUISITION: Articles that reported on disuse atrophy and muscle atrophy after traumatic joint injury were collected from peer-reviewed sources available on PubMed (2000 through December 2019). Search terms included the following: disuse muscle atrophy OR disuse muscle mass OR anterior cruciate ligament OR ACL AND mechanism OR muscle loss OR atrophy OR neurological disruption OR rehabilitation OR exercise. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 5. RESULTS: We highlight that (1) muscle atrophy after traumatic joint injury is due to a broad range of atrophy-inducing factors that are resistant to standard resistance exercises and need to be effectively targeted with treatments and (2) neurological disruptions after traumatic joint injury uncouple the nervous system from muscle tissue, contributing to a more complex manifestation of muscle loss as well as degraded tissue quality. CONCLUSION: Atrophy occurring after traumatic joint injury is distinctly different from the muscle atrophy that develops from disuse and is likely due to the broad range of atrophy-inducing factors that are present after injury. Clinicians must challenge the standard prescriptive approach to combating muscle atrophy from simply prescribing physical activity to targeting the neurophysiological origins of muscle atrophy after traumatic joint injury.


Assuntos
Lesões do Ligamento Cruzado Anterior/complicações , Atrofia Muscular/etiologia , Lesões do Ligamento Cruzado Anterior/patologia , Lesões do Ligamento Cruzado Anterior/fisiopatologia , Citocinas/sangue , Exercício Físico/fisiologia , Humanos , Fibras Musculares Esqueléticas/fisiologia , Proteínas Musculares/biossíntese , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Miostatina/fisiologia , Proteólise , Células Satélites de Músculo Esquelético/fisiologia
8.
Am J Physiol Heart Circ Physiol ; 319(3): H571-H581, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32734815

RESUMO

Salt intake may alter blood pressure (BP) regulation, but no study has investigated the impact of salt reduction versus salt loading on morning blood pressure surge (MBPS) and sympathetic neural control in premenopausal women with a history of normal pregnancy. Nine healthy women (42 ± 3 yr; mean ± SD) were given a low-salt diet (LS; 50 mEq sodium/day) and high-salt diet (HS; 250 mEq sodium/day) for 1 wk each (~2 mo apart with the order randomized), while water intake was ad libitum. Ambulatory BP at 24 h was measured, and the percent change in blood volume (BV) was calculated following LS and HS. MBPS was defined as the morning systolic BP (averaged for 2 h after wake-up) minus the lowest nocturnal systolic BP. Beat-by-beat BP, heart rate, and muscle sympathetic nerve activity (MSNA) were measured during supine rest. Signal averaging was used to characterize changes in beat-by-beat mean arterial pressure and total vascular conductance following spontaneous MSNA bursts to assess sympathetic vascular transduction. Ambulatory BP and MBPS (32 ± 7 vs. 26 ± 12 mmHg, P = 0.208) did not differ between LS and HS. From LS to HS, BV increased by 4.3 ± 3.7% (P = 0.008). MSNA (30 ± 20 vs. 18 ± 13 bursts/100 heartbeats, P = 0.005) was higher, whereas sympathetic vascular transduction was lower in LS than HS (both, P < 0.01). Changes in MSNA from LS to HS were correlated to percent changes in BV (r = -0.673; P = 0.047). Thus, salt intake affects sympathetic neural control but not MBPS in premenopausal women with a history of normal pregnancy. The underlying mechanisms remain unknown; however, alterations in sympathetic vascular transduction may, in part, contribute.NEW & NOTEWORTHY This is the first study to demonstrate that MBPS and ambulatory BP were not affected by salt intake despite a significant change in sympathetic outflow in healthy premenopausal women with a history of normal pregnancy. This may be due to compensatory adaptations in MSNA and sympathetic vascular transduction during salt reduction versus salt loading.


Assuntos
Pressão Sanguínea , Sistema Cardiovascular/inervação , Ritmo Circadiano , Dieta Hipossódica , Músculo Esquelético/inervação , Cloreto de Sódio na Dieta/administração & dosagem , Sistema Nervoso Simpático/fisiologia , Adaptação Fisiológica , Adulto , Estudos Cross-Over , Feminino , Frequência Cardíaca , Humanos , Pessoa de Meia-Idade , Paridade , Gravidez , Pré-Menopausa , Estudos Prospectivos , Distribuição Aleatória , Fatores de Tempo
9.
Am J Physiol Heart Circ Physiol ; 319(3): H531-H538, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32734818

RESUMO

It has been suggested that sex differences in acute blood pressure fluctuations occur during the periods of time between bursts of muscle sympathetic nerve activity. Therefore, we tested the hypothesis that men experience more dynamic changes in mean arterial pressure (Finometer MIDI) than women during acute sympathoinhibition (i.e., slow breathing) in which bursts of sympathetic activity occur more infrequently than at rest. We tested healthy women (n = 9) and men (n = 9) of similar age (22 ± 2 vs. 23 ± 3 yr, P = 0.6). Custom software was used to calculate beat-by-beat changes in blood pressure following sympathetic burst and nonburst sequences (recorded using microneurography) during 10 min of supine rest and a 15-min bout of slow breathing. During slow breathing following nonburst sequences, women demonstrated smaller overall reductions in mean arterial pressure compared with men over the subsequent 15 cardiac cycles (P < 0.01). In addition, following a burst of sympathetic activity, women experienced greater overall increases in mean arterial pressure compared with men over the following 15 cardiac cycles (P < 0.01). Despite these differences, the peak and nadir changes in arterial pressure following burst and nonburst sequences were not different between the sexes (P = 0.45 and P = 0.48, burst and nonburst sequences, respectively). As such, these data suggest that women respond to a burst of sympathetic activity with more sustained increases in blood pressure than men, coupled with improved maintenance of blood pressure during acute periods of sympathetic quiescence. In other words, these findings suggest that men rely more on frequent bursts of sympathetic activity to acutely regulate arterial pressure than women.NEW & NOTEWORTHY We demonstrate that during acute sympathoinhibition, women demonstrate more sustained increases in blood pressure following sympathetic bursts of activity than men. Likewise, during prolonged sympathetic quiescence, blood pressure is less labile in women than men. This suggests that lower overall blood pressure in young women may not be mediated by smaller beat-by-beat changes in blood pressure in response to sympathetic outflow but may instead be mediated by a lower frequency of sympathetic bursts.


Assuntos
Pressão Arterial , Sistema Cardiovascular/inervação , Frequência Cardíaca , Músculo Esquelético/inervação , Sistema Nervoso Simpático/fisiologia , Adulto , Feminino , Humanos , Masculino , Inibição Neural , Distribuição Aleatória , Mecânica Respiratória , Fatores Sexuais , Fatores de Tempo , Adulto Jovem
10.
Am J Physiol Heart Circ Physiol ; 319(4): H787-H792, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32857604

RESUMO

Fluctuations in diastolic pressure modulate muscle sympathetic nerve activity (MSNA) through the arterial baroreflex. A higher sympathetic baroreflex sensitivity (sBRS) to pressure falls compared with rises has been reported; however, the underlying mechanisms are unclear. We assessed whether beat-to-beat falling and rising diastolic pressures operate on two distinct baroreflex response curves. Twenty-two men (32 ± 8 yr) underwent sequential bolus injections of nitroprusside and phenylephrine (modified Oxford test) with continuous recording of heart rate, blood pressure, and MSNA. The weighted negative linear regression slope between falling or rising diastolic pressure and MSNA burst incidence quantified sBRSfall and sBRSrise, respectively. The diastolic pressure evoking a MSNA burst incidence of 50 (T50) was calculated. sBRSfall was greater than sBRSrise (-6.24 ± 2.80 vs. -4.34 ± 2.16 bursts·100 heartbeats-1·mmHg-1, P = 0.01) and had a narrower operating range (14 ± 8 vs. 20 ± 10 mmHg, P = 0.01) that was shifted rightward (T50, 75 ± 9 and 70 ± 11 mmHg, P < 0.001). At diastolic pressures below baseline, sBRSfall was less than sBRSrise (-1.81 ± 1.31 vs. -3.59 ± 1.70 bursts·100 heartbeats-1·mmHg-1, P = 0.003) as low absolute pressures operated closer to the saturation plateau on the falling, compared with the rising pressure curve. At pressures above baseline, sBRSfall was greater than sBRSrise (-5.23 ± 1.94 and -3.79 ± 1.67 bursts·100 heartbeats-1·mmHg-1, P = 0.03). These findings demonstrate that the sympathetic arterial baroreflex possesses two response curves for processing beat-to-beat diastolic pressure falls and rises. The falling pressure curve is rightward shifted, which reduces sensitivity to falling pressure at low absolute pressures. This demonstrates that the direction of the hysteresis is influenced by the prevailing pressure level relative to each baroreflex response curve.NEW & NOTEWORTHY The findings show that the arterial baroreflex processes diastolic pressure dependent on the direction of pressure change from the previous beat, yielding two distinct baroreflex response curves to falling and rising pressure. Overall, the falling pressure curve is rightward shifted and more sensitive. The rightward shift caused a hysteresis reversal at hypotensive pressures as the falling pressure saturation plateau of the sigmoid response curve occurred at higher pressures than the rising pressure curve.


Assuntos
Pressão Arterial , Barorreflexo , Frequência Cardíaca , Músculo Esquelético/inervação , Nervo Fibular/fisiologia , Sistema Nervoso Simpático/fisiologia , Adulto , Pressão Arterial/efeitos dos fármacos , Barorreflexo/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Fatores de Tempo , Vasoconstritores/farmacologia , Vasodilatadores/farmacologia
11.
Int. j. morphol ; 38(4): 1096-1105, Aug. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1124901

RESUMO

Los músculos lumbricales (ML) de la mano humana son claves en la propiocepción de la flexoextensión de los dedos. La descripción de su inervación indica que el nervio mediano (NM) inerva los dos ML laterales (L1 y L2) y el nervio ulnar (NU) los ML mediales (L3 y L4). Diversos autores han reportado una gran variabilidad de esta inervación, tanto en los nervios que entregan ramos para estos músculos, como también en la distribución de sus ramos y la presencia de troncos comunes. Por otra parte, el número de ramos que recibe cada ML y los puntos motores (Pm) de los mismos ha sido escasamente reportado. El objetivo de este estudio fue determinar número, ubicación y Pm de los ramos destinados a los ML de la mano humana. Así mismo se estableció el patrón de inervación más frecuente. Para ello se utilizaron 24 manos formalizadas, pertenecientes al laboratorio de Anatomía, de la Universidad Andrés Bello, sede Viña del Mar, Chile. Se realizó una disección convencional por planos de profundidad. En todos los casos, el ramo del músculo L1 se originó del nervio digital palmar propio lateral del dedo índice, de la misma forma, en el 100 % el L2 fue inervado por un ramo del nervio digital palmar común del segundo espacio interóseo. En relación a los ML mediales en un 100 % ambos músculos fueron inervados por ramos del ramo profundo del NU (RPNM). En el caso del L3 en un 92 % se presentó un tronco común con el segundo músculo interóseo palmar, asimismo para L4 existió un tronco común con el tercer músculo interóseo palmar en un 79 %. En el 29 %, el L3 presentó una inervación dual. Considerando como referencia la línea biestiloidea, los Pm de los ramos del NM fue de 63,96 mm para L1; 67,91 mm para L2 y 68,69 mm para L3. Para los ramos provenientes del RPNU fue de 69,87 mm para L3 y 69, 21 mm para L4. Los resultados obtenidos aportan al conocimiento anatómico de la inervación de los músculos lumbricales y es de utilidad en procedimientos de neurocirugía que busquen la restauración de la funcionalidad de la mano.


The lumbrical muscles (LM) of the human hand are key in proprioception of flexion and finger extension. The description of its innervation indicates that the median nerve (MN) innervates the two lateral LMs (L1 and L2) and the ulnar nerve (UN) the medial LMs (L3 and L4). Various authors have reported a great variability of this innervation, both in which nerve delivers branches for these muscles, as well as in the distribution of their branches and the presence of common trunks. On the other hand, the number of branches that each LM receives and the motor points (Mp) of these have been scarcely reported. The aim of this study was to determine the number, location and Mp of the branches destined for the LM of the human hand. Likewise, the most frequent innervation pattern was established. For this, 24 formalized hands, belonging to the anatomy laboratory, of the Universidad Andrés Bello, Viña del Mar, Chile, were used. Conventional depth plane dissection was performed. In all cases, the branch of the L1 muscle originated from the palmar digital nerve proper to the index finger, in the same way, in 100 % the L2 was supplied with a branch of the common palmar digital nerve from the second interosseous space. In relation to the LM, in 100 % both muscles were innervated by branches of the deep branch of the UN (DBUN). In the case of L3, 92 % presented a common trunk with the second palmar interosseous muscle. Likewise, in 79 % of the cases, there was a common trunk between the L4 and the third palmar interosseous muscle. In 29 %, the L3 presented a dual innervation. The distance between of the Mp-BEstL was 63.96 mm for L1, 67.91 mm for L2 and 68.69 mm for L3. This distance was 69.87 mm for L3 and 69, 21 mm for L4. The results obtained contribute to the anatomical knowledge of the innervation of the lumbrical muscles and is useful in neurosurgery procedures that seek to restore the functionality of the hand.


Assuntos
Humanos , Adulto , Nervo Ulnar/anatomia & histologia , Músculo Esquelético/inervação , Mãos/inervação , Nervo Mediano/anatomia & histologia , Cadáver , Variação Anatômica
12.
Int. j. morphol ; 38(4): 1010-1017, Aug. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1124890

RESUMO

RESUMEN: El músculo extensor corto de los dedos (ECD) se sitúa junto con el músculo extensor corto del hallux (ECH) en la región dorsal del pie y están encargados de colaborar con la acción agonista de los músculos extensor largo de los dedos (ELD) y extensor largo del hallux (ELH), en la extensión de los cuatro dedos mediales en las articulaciones metatarsofalángicas. Esta condición complementaria permite su transferencia quirúrgica hacia otras regiones receptoras sin afectar la funcionalidad extensora de los dedos del pie motivo por el cual durante las últimas décadas se ha convertido en un tejido importante para la reconstrucción de lesiones tisulares, sin embargo, son escasos los estudios biométricos que lo describan en detalle. El objetivo de esta investigación fue establecer la longitud, ancho y área de extensión de estos músculos acompañada de la determinación de las distancias de éstos respecto a la cuña medial y la base del quinto metatarsiano para su uso quirúrgico. Sumado a lo anterior y posterior a la descripción de las variantes musculares encontradas se determinó los puntos motores de inervación de estos dos músculos. Para ello se estudiaron 36 miembros inferiores formolizados de individuos adultos brasileños pertenecientes a la Universidad Federal de Alagoas (UFAL), Maceió, Brasil. Las mediciones se realizaron con un cáliper marca Mitutoyo de 0,01 mm de precisión obteniendo una longitud, ancho y área de 6,89 ± 1,64 cm, 3,81 ± 0,42 cm y 31,98 ± 7,60 cm2 en el lado derecho de 6,91 ± 1,64 cm, 3,68 ± 0,46 cm y 30,75 ± 7,61 cm2 en el izquierdo respectivamente. En el 17 % de los casos hay presencia de tendones accesorios para el músculo ECD. La distancia desde el margen medial del músculo ECH respecto a la cuña medial y del margen lateral del músculo ECD a la base del quinto metatarsiano fue de 1,97 ± 0,43 y 1,72 ± 0,41 al lado derecho y de 2,01 ± 0,62 y 1,87 ± 0,36 al lado izquierdo respectivamente. Los puntos motores (Pm) predominaron en un 64 % en el tercio medio del músculo ECH y en un 64 % en el tercio proximal del músculo ECD. Estos resultados son un aporte significativo, tanto para quienes realizan cirugía ortopédica como para el conocimiento detallado de la anatomía dorsal del pie.


SUMMARY: The extensor digitorum brevis muscle (EDB) is located along with the extensor hallucis brevis (EHD) in the dorsal region of the foot and are responsible for collaborating with the agonist action of the extensor digitorum longus muscles (EDL) and extensor hallucis longus (EHL) in the extension of the four medial fingers in the metatarsophalangeal joints. This complementary condition allows its surgical transfer to other receptor regions without affecting the extensor functionality of the toes, which is why during the last decades it has become an important tissue for the reconstruction of tissue injuries, however, there are few studies biometrics that describe it in detail. The objective of this investigation was to establish the length, width and area of extension of these muscles accompanied by the determination of their distances from the medial wedge and the base of the fifth metatarsal for surgical use. In addition to the above and after the description of the muscle variants found, the innervation motor points of these two muscles were determined. To do this, 36 formalized lower limbs of Brazilian adult individuals belonging to the Federal University of Alagoas (UFAL), Maceió, Brazil, were studied. Measurements were made with a 0.01 mm precision Mitutoyo caliper obtaining a length, width and area of 6.89 ± 1.64 cm, 3.81 ± 0.42 cm and 31.98 ± 7.60 cm2 on the right side of 6.91 ± 1.64 cm, 3.68 ± 0.46 cm and 30.75 ± 7.61 cm2 on the left, respectively. In 17 % of cases there is presence of accessory tendons for the EDB muscle. The distance from the medial margin of the EHB muscle with respect to the medial wedge and the lateral margin of the EDB muscle to the base of the fifth metatarsal was 1.97 ± 0.43 and 1.72 ± 0.41 on the right side and 2,01 ± 0.62 and 1.87 ± 0.36 on the left side respectively. Motor points (Pm) predominated in 64 % in the middle third of the EHB muscle and in 64 % in the proximal third of the EDB muscle. These results are a significant contribution both for those who perform orthopedic surgery and for detailed knowledge of the dorsal foot anatomy.


Assuntos
Humanos , Masculino , Feminino , Adulto , Hallux/anatomia & histologia , Dedos do Pé/anatomia & histologia , Músculo Esquelético/anatomia & histologia , Retalhos Cirúrgicos , Brasil , Músculo Esquelético/inervação , Pé/anatomia & histologia
13.
Exerc Sport Sci Rev ; 48(4): 209-216, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32658041

RESUMO

This review discusses evidence suggesting that group III/IV muscle afferents affect locomotor performance by influencing neuromuscular fatigue. These neurons regulate the hemodynamic and ventilatory response to exercise and, thus, assure appropriate locomotor muscle O2 delivery, which optimizes peripheral fatigue development and facilitates endurance performance. In terms of central fatigue, group III/IV muscle afferents inhibit motoneuronal output and thereby limit exercise performance.


Assuntos
Exercício Físico/fisiologia , Neurônios Motores/fisiologia , Músculo Esquelético/inervação , Neurônios Aferentes/fisiologia , Resistência Física/fisiologia , Fadiga/fisiopatologia , Hemodinâmica , Humanos , Fadiga Muscular/fisiologia , Músculo Esquelético/metabolismo , Consumo de Oxigênio , Respiração
14.
Am J Physiol Heart Circ Physiol ; 319(2): H370-H376, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32648822

RESUMO

Changes in the arterial baroreflex arc contribute to elevated sympathetic outflow and altered reflex control of blood pressure with human aging. Using ultrasound and sympathetic microneurography (muscle sympathetic nerve activity, MSNA) we investigated the relationships between aortic and carotid artery wall tension (indices of baroreceptor activation) and the vascular sympathetic baroreflex operating point (OP; MSNA burst incidence) in healthy, normotensive young (n = 27, 23 ± 3 yr) and middle-aged men (n = 22, 55 ± 4 yr). In young men, the OP was positively related to the magnitude and rate of unloading and time spent unloaded in the aortic artery (r = 0.56, 0.65, and 0.51, P = 0.02, 0.003, and 0.03), but not related to the magnitude or rate of unloading or time spent unloaded in the carotid artery (r = -0.32, -0.07, and 0.06, P = 0.25, 0.81, and 0.85). In contrast, in middle-aged men, the OP was not related to either the magnitude or rate of unloading or time spent unloaded in the aortic (r = 0.22, 0.21, and 0.27, P = 0.41, 0.43, and 0.31) or carotid artery (r = 0.06, 0.28, and -0.01; P = 0.48, 0.25, and 0.98). In conclusion, in young men, aortic unloading mechanics may play a role in determining the vascular sympathetic baroreflex OP. In contrast, in middle-aged men, barosensory vessel unloading mechanics do not appear to determine the vascular sympathetic baroreflex OP and, therefore, do not contribute to age-related arterial baroreflex resetting and increased resting MSNA.NEW & NOTEWORTHY We assessed the influence of barosensory vessel mechanics (magnitude and rate of unloading and time spent unloaded) as a surrogate for baroreceptor unloading. In young men, aortic unloading mechanics are important in regulating the operating point of the vascular sympathetic baroreflex, whereas in middle-aged men, these arterial mechanics do not influence this operating point. The age-related increase in resting muscle sympathetic nerve activity does not appear to be driven by altered baroreceptor input from stiffer barosensory vessels.


Assuntos
Envelhecimento , Aorta/inervação , Pressão Arterial , Barorreflexo , Artérias Carótidas/inervação , Músculo Esquelético/inervação , Pressorreceptores/fisiologia , Adulto , Fatores Etários , Aorta/diagnóstico por imagem , Artérias Carótidas/diagnóstico por imagem , Frequência Cardíaca , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Ultrassonografia , Adulto Jovem
16.
J Stroke Cerebrovasc Dis ; 29(8): 104998, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32689598

RESUMO

BACKGROUND: Little is known about the existence and impact of interactions among multiple impairments to gait independence. The purpose of this study is to reveal the interaction of physical functions and its impact on gait independence in stroke patients. METHODS: This retrospective study included 108 subacute stroke patients. We conducted a decision tree analysis to examine the existence of interactions in relation to gait independence among the gross motor function of lower limb, knee extension strength, sensory function, and trunk function. Further, we confirmed the existence and impact of interaction detected via the decision tree after adjusting for the effects of confounding factors using logistic regression. RESULTS: The knee extension strength and proprioception on the affected side were selected in the first and second level of the decision tree. In addition, the knee extension strength was selected in the third level. The interaction of the knee extension strength and proprioception on the affected side was significantly associated with gait independence, both before and after adjusting for age, visuospatial perception, and cognitive functions. CONCLUSIONS: Our results suggest that the interaction of the knee extension strength and proprioception on the affected side is strongly associated with gait independence in stroke patients.


Assuntos
Árvores de Decisões , Marcha , Vida Independente , Joelho/inervação , Força Muscular , Músculo Esquelético/inervação , Propriocepção , Acidente Vascular Cerebral/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Avaliação da Deficiência , Feminino , Análise da Marcha , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Recuperação de Função Fisiológica , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/psicologia , Acidente Vascular Cerebral/terapia , Reabilitação do Acidente Vascular Cerebral
17.
Eur. j. anat ; 24(4): 281-284, jul. 2020. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-193961

RESUMO

Severe hamstring injuries warranting surgical repair are rare and mainly affect athletes, young and middle-aged people. A minority of these patients report postoperative complications of denervation. Symptoms of denervation range from muscle weakness to sciatic nerve palsy. Recent anatomical observations suggest that a recurrent motor nerve, which inserts into the proximal ham-strings, may be responsible for this denervation. The recurrent motor nerve was identified through cadaveric dissection and the site of nerve penetration into the muscle, measured 1.5 cm from the ischial tuberosity. This distance is significantly shorter than previous studies report. Awareness of this nerve branch is an important consideration in hamstring injury and repair. Due to its course, the recurrent motor nerve’s name is also a source of discussion


No disponible


Assuntos
Humanos , Nervo Isquiático/anatomia & histologia , Denervação/métodos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/inervação , Cadáver , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Nervos Periféricos/anatomia & histologia
18.
PLoS Genet ; 16(6): e1008830, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32502192

RESUMO

Many post-transcriptional mechanisms operate via mRNA 3'UTRs to regulate protein expression, and such controls are crucial for development. We show that homozygous mutations in two zebrafish exon junction complex (EJC) core genes rbm8a and magoh leads to muscle disorganization, neural cell death, and motor neuron outgrowth defects, as well as dysregulation of mRNAs subjected to nonsense-mediated mRNA decay (NMD) due to translation termination ≥ 50 nts upstream of the last exon-exon junction. Intriguingly, we find that EJC-dependent NMD also regulates a subset of transcripts that contain 3'UTR introns (3'UI) < 50 nts downstream of a stop codon. Some transcripts containing such stop codon-proximal 3'UI are also NMD-sensitive in cultured human cells and mouse embryonic stem cells. We identify 167 genes that contain a conserved proximal 3'UI in zebrafish, mouse and humans. foxo3b is one such proximal 3'UI-containing gene that is upregulated in zebrafish EJC mutant embryos, at both mRNA and protein levels, and loss of foxo3b function in EJC mutant embryos significantly rescues motor axon growth defects. These data are consistent with EJC-dependent NMD regulating foxo3b mRNA to control protein expression during zebrafish development. Our work shows that the EJC is critical for normal zebrafish development and suggests that proximal 3'UIs may serve gene regulatory function in vertebrates.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Neurogênese/genética , Degradação do RNAm Mediada por Códon sem Sentido/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Regiões 3' não Traduzidas/genética , Animais , Animais Geneticamente Modificados , Axônios/fisiologia , Códon de Terminação , Conjuntos de Dados como Assunto , Embrião não Mamífero , Éxons/genética , Redes Reguladoras de Genes/genética , Homozigoto , Humanos , Íntrons/genética , Camundongos , Músculo Esquelético/inervação , Mutagênese , Mutação , Crescimento Neuronal/genética , Proteínas Nucleares/genética , Terminação Traducional da Cadeia Peptídica , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , RNA-Seq , Alinhamento de Sequência , Regulação para Cima , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento
19.
Am J Physiol Heart Circ Physiol ; 319(1): H192-H202, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502375

RESUMO

Sympathetic vasoconstriction is mediated by α-adrenergic receptors under resting conditions. During exercise, increased sympathetic nerve activity (SNA) is directed to inactive and active skeletal muscle; however, it is unclear what mechanism(s) are responsible for vasoconstriction during large muscle mass exercise in humans. The aim of this study was to determine the contribution of α-adrenergic receptors to sympathetic restraint of inactive skeletal muscle and active skeletal muscle during cycle exercise in healthy humans. In ten male participants (18-35 yr), mean arterial pressure (intra-arterial catheter) and forearm vascular resistance (FVR) and conductance (FVC) were assessed during cycle exercise (60% total peak workload) alone and during combined cycle exercise + handgrip exercise (HGE) before and after intra-arterial blockade of α- and ß-adrenoreceptors via phentolamine and propranolol, respectively. Cycle exercise caused vasoconstriction in the inactive forearm that was attenuated ~80% with adrenoreceptor blockade (%ΔFVR, +81.7 ± 84.6 vs. +9.7 ± 30.7%; P = 0.05). When HGE was performed during cycle exercise, the vasodilatory response to HGE was restrained by ~40% (ΔFVC HGE, +139.3 ± 67.0 vs. cycle exercise: +81.9 ± 66.3 ml·min-1·100 mmHg-1; P = 0.03); however, the restraint of active skeletal muscle blood flow was not due to α-adrenergic signaling. These findings highlight that α-adrenergic receptors are the primary, but not the exclusive mechanism by which sympathetic vasoconstriction occurs in inactive and active skeletal muscle during exercise. Metabolic activity or higher sympathetic firing frequencies may alter the contribution of α-adrenergic receptors to sympathetic vasoconstriction. Finally, nonadrenergic vasoconstrictor mechanisms may be important for understanding the regulation of blood flow during exercise.NEW & NOTEWORTHY Sympathetic restraint of vascular conductance to inactive skeletal muscle is critical to maintain blood pressure during moderate- to high-intensity whole body exercise. This investigation shows that cycle exercise-induced restraint of inactive skeletal muscle vascular conductance occurs primarily because of activation of α-adrenergic receptors. Furthermore, exercise-induced vasoconstriction restrains the subsequent vasodilatory response to hand-grip exercise; however, the restraint of active skeletal muscle vasodilation was in part due to nonadrenergic mechanisms. We conclude that α-adrenergic receptors are the primary but not exclusive mechanism by which sympathetic vasoconstriction restrains blood flow in humans during whole body exercise and that metabolic activity modulates the contribution of α-adrenergic receptors.


Assuntos
Antagonistas Adrenérgicos alfa/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Exercício Físico , Músculo Esquelético/fisiologia , Sistema Nervoso Simpático/fisiologia , Adulto , Pressão Sanguínea , Humanos , Masculino , Contração Muscular , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/inervação , Fentolamina/farmacologia , Propranolol/farmacologia , Fluxo Sanguíneo Regional , Sistema Nervoso Simpático/efeitos dos fármacos , Vasoconstrição , Vasodilatação
20.
Plast Reconstr Surg ; 146(1): 128-132, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32590654

RESUMO

Supercharge end-to-side anterior interosseous-to-ulnar motor nerve transfer is commonly performed in the authors' institution to augment intrinsic hand function. Following observations of recovery patterns, the authors hypothesized that despite its more distal innervation, the first dorsal interosseous muscle recovers to a greater extent than the abductor digiti minimi muscle. The objective of this work was to evaluate the clinical and electrodiagnostic pattern of reinnervation of intrinsic hand musculature following supercharge end-to-side anterior interosseous-to-ulnar motor nerve transfer. A retrospective cohort of prospectively collected data included all patients who underwent a supercharge end-to-side anterior interosseous-to-ulnar motor nerve transfer. Two independent reviewers performed data collection. Reinnervation was assessed with two primary outcome measures: (1) clinically, with serial Medical Research Council strength assessments; and (2) electrodiagnostically, with serial motor amplitude measurements. Statistical analysis was performed using nonparametric statistics. Seventeen patients (65 percent male; mean age, 56.9 ± 13.3 years) were included with a mean follow-up of 16.7 ± 8.5 months. Preoperatively, all patients demonstrated clinically significant weakness and electrodiagnostic evidence of denervation. Postoperatively, strength and motor amplitude increased significantly for both the first dorsal interosseous muscle (p = 0.002 and p = 0.016) and the abductor digiti minimi muscle (p = 0.044 and p = 0.015). Despite comparable preoperative strength (p = 0.098), postoperatively, the first dorsal interosseous muscle achieved significantly greater strength when compared to the abductor digiti minimi muscle (p = 0.023). Following supercharge end-to-side anterior interosseous-to-ulnar motor nerve transfer, recovery of intrinsic muscle function differs between the abductor digiti minimi and the first dorsal interosseous muscles, with better recovery observed in the more distally innervated first dorsal interosseous muscle. Further work to elucidate the underlying physiologic and anatomical basis for this discrepancy is indicated. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.


Assuntos
Mãos/inervação , Músculo Esquelético/inervação , Transferência de Nervo/métodos , Nervo Ulnar , Adulto , Idoso , Animais , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica/fisiologia , Estudos Retrospectivos , Nervo Ulnar/lesões , Nervo Ulnar/cirurgia
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