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1.
Exp Neurol ; 347: 113879, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34597682

RESUMO

Reaching to grasp is an evolutionarily conserved behavior and a crucial part of the motor repertoire in mammals. As it is studied in the laboratory, reaching has become the prototypical example of dexterous forelimb movements, illuminating key principles of motor control throughout the spinal cord, brain, and peripheral nervous system. Here, we (1) review the motor elements or phases that comprise the reach, grasp, and retract movements of reaching behavior, (2) highlight the role of intersectional genetic tools in linking these movements to their neuronal substrates, (3) describe spinal cord cell types and their roles in skilled reaching, and (4) how descending pathways from the brain and the sensory systems contribute to skilled reaching. We emphasize that genetic perturbation experiments can pin-point the neuronal substrates of specific phases of reaching behavior.


Assuntos
Técnicas Genéticas , Modelos Animais , Destreza Motora/fisiologia , Animais , Encéfalo/fisiologia , Vias Eferentes/fisiologia , Camundongos , Medula Espinal/fisiologia
2.
Codas ; 34(1): e20200300, 2021.
Artigo em Português, Inglês | MEDLINE | ID: mdl-34730665

RESUMO

PURPOSE: The goal of this study is to investigate the efferent auditory pathways inhibition in Turner's syndrome and to relate it to the cytogenetic profile. METHODS: This is a cross-sectional study with a comparison group. A sample with 94 participants divided into two groups: The study group was a sample of 40 patients diagnosed with Turner's syndrome (17.6 years of age). The control group was composed of 54 volunteers (18.9 years of age), female, without syndrome. The selected individuals were submitted to efferent auditory pathways inhibition research. RESULTS: The mean of the inhibitory effect of the efferent auditory pathway in the study group in the right ear was 0.4 dB and in the comparison group it was 1.9 dB, however in the left ear the mean of the inhibitory effect of the efferent auditory pathway was 1.4 dB in the study group and 0.8 dB in the comparison group. The inhibitory effect of the efferent auditory pathway was present in 14 individuals with monosomy and in 15 with other cytogenetic alterations. CONCLUSIONS: In the study group, the efferent auditory pathways inhibition value was significantly higher in the left ear and significantly lower than the control group in the right ear. There was no significant difference in efferent auditory pathways inhibition of right ear and left ear between the karyotype types.


Assuntos
Vias Auditivas , Síndrome de Turner , Estudos Transversais , Vias Eferentes , Feminino , Humanos
3.
Sci Rep ; 11(1): 17910, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34504145

RESUMO

The neurophysiological mechanisms underlying the behavioural improvements usually associated with an external (EF) compared with an internal focus of attention (IF) remain poorly investigated. Surround inhibition in the primary cortex has been shown to be more pronounced with an EF, indicating a more spatial restriction of the motor command. However, the influence of different foci on the temporal aspect of the motor command, such as the modulation of fast versus slow(er) motor pathways, remains unknown and was therefore investigated in this study. Fourteen participants were asked to press on a pedal with the right foot to match its position with a target line displayed on a screen. The deviation of the pedal from the target line was used as a behavioural parameter and compared between both foci (EF vs IF). Additionally, conditioned H-reflexes were evoked during the motor task to assess the excitability of fast (direct) and slower (more indirect) motor pathways when adopting an EF or IF. With an EF compared to an IF, the motor performance was enhanced (P = .001; + 24%) and the activation of slow(er) motor pathways was reduced (P < 0.001, - 11.73%). These findings demonstrate for the first time that using different attentional strategies (EF and IF) has an influence on the excitability of slow(er) motor pathways. Together with the increased intracortical inhibition and surround inhibition known from previous studies, the diminished activation in the slow(er) motor pathways further explains why using an EF is a more economic strategy.


Assuntos
Atenção/fisiologia , Vias Eferentes , Reflexo H , Córtex Motor , Desempenho Psicomotor , Adulto , Humanos , Masculino
4.
Artigo em Inglês | MEDLINE | ID: mdl-34343095

RESUMO

A hallmark impairment in a hemiparetic stroke is a loss of independent joint control resulting in abnormal co-activation of shoulder abductor and elbow flexor muscles in their paretic arm, clinically known as the flexion synergy. The flexion synergy appears while generating shoulder abduction (SABD) torques as lifting the paretic arm. This likely be caused by an increased reliance on contralesional indirect motor pathways following damage to direct corticospinal projections. The assessment of functional connectivity between brain and muscle signals, i.e., brain-muscle connectivity (BMC), may provide insight into such changes to the usage of motor pathways. Our previous model simulation shows that multi-synaptic connections along the indirect motor pathway can generate nonlinear connectivity. We hypothesize that increased usage of indirect motor pathways (as increasing SABD load) will lead to an increase of nonlinear BMC. To test this hypothesis, we measured brain activity, muscle activity from shoulder abductors when stroke participants generate 20% and 40% of maximum SABD torque with their paretic arm. We computed both linear and nonlinear BMC between EEG and EMG. We found dominant nonlinear BMC at contralesional/ipsilateral hemisphere for stroke, whose magnitude increased with the SABD load. These results supported our hypothesis and indicated that nonlinear BMC could provide a quantitative indicator for determining the usage of indirect motor pathways following a hemiparetic stroke.


Assuntos
Acidente Vascular Cerebral , Vias Eferentes , Eletromiografia , Humanos , Movimento , Paresia/etiologia , Amplitude de Movimento Articular , Ombro , Acidente Vascular Cerebral/complicações
5.
Nature ; 592(7854): 414-420, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33828296

RESUMO

Critical periods-brief intervals during which neural circuits can be modified by activity-are necessary for proper neural circuit assembly. Extended critical periods are associated with neurodevelopmental disorders; however, the mechanisms that ensure timely critical period closure remain poorly understood1,2. Here we define a critical period in a developing Drosophila motor circuit and identify astrocytes as essential for proper critical period termination. During the critical period, changes in activity regulate dendrite length, complexity and connectivity of motor neurons. Astrocytes invaded the neuropil just before critical period closure3, and astrocyte ablation prolonged the critical period. Finally, we used a genetic screen to identify astrocyte-motor neuron signalling pathways that close the critical period, including Neuroligin-Neurexin signalling. Reduced signalling destabilized dendritic microtubules, increased dendrite dynamicity and impaired locomotor behaviour, underscoring the importance of critical period closure. Previous work defined astroglia as regulators of plasticity at individual synapses4; we show here that astrocytes also regulate motor circuit critical period closure to ensure proper locomotor behaviour.


Assuntos
Astrócitos/fisiologia , Período Crítico Psicológico , Drosophila melanogaster/citologia , Drosophila melanogaster/fisiologia , Vias Eferentes/fisiologia , Neurônios Motores/fisiologia , Plasticidade Neuronal/fisiologia , Animais , Moléculas de Adesão Celular Neuronais/metabolismo , Dendritos/fisiologia , Feminino , Locomoção/fisiologia , Masculino , Microtúbulos/metabolismo , Neurópilo/fisiologia , Receptores de Superfície Celular/metabolismo , Transdução de Sinais , Sinapses/fisiologia , Fatores de Tempo
6.
FASEB J ; 35(5): e21486, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33811700

RESUMO

The cochlear efferent feedback system plays important roles in auditory processing, including regulation of the dynamic range of hearing, and provides protection against acoustic trauma. These functions are performed through medial olivocochlear (MOC) neurons. However, the underlying cellular and molecular mechanisms are not fully understood. The serotonin type 3A (5-HT3A) receptor is widely expressed throughout the nervous system, which suggests important roles in various neural functions. However, involvement of the 5-HT3A receptor in the MOC system remains unclear. We used mice in this study and found that the 5-HT3A receptor was expressed in MOC neurons that innervated outer hair cells in the cochlea and was involved in the activation of MOC neurons by noise exposure. 5-HT3A receptor knockout impaired MOC functions, potentiated noise-induced hearing loss, and increased loss of ribbon synapses following noise exposure. Furthermore, 5-HT3 receptor agonist treatment alleviated the noise-induced hearing loss and loss of ribbon synapses, which enhanced cochlear protection provided by the MOC system. Our findings demonstrate that the 5-HT3A receptor plays fundamental roles in the MOC system and critically contributes to protection from noise-induced hearing impairment.


Assuntos
Cóclea/fisiologia , Células Ciliadas Auditivas Externas/patologia , Perda Auditiva Provocada por Ruído/prevenção & controle , Ruído/efeitos adversos , Receptores 5-HT3 de Serotonina/fisiologia , Animais , Vias Eferentes , Perda Auditiva Provocada por Ruído/etiologia , Perda Auditiva Provocada por Ruído/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
7.
Nutrients ; 13(3)2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33799575

RESUMO

The regulation of energy balance requires the complex integration of homeostatic and hedonic pathways, but sensory inputs from the gastrointestinal (GI) tract are increasingly recognized as playing critical roles. The stomach and small intestine relay sensory information to the central nervous system (CNS) via the sensory afferent vagus nerve. This vast volume of complex sensory information is received by neurons of the nucleus of the tractus solitarius (NTS) and is integrated with responses to circulating factors as well as descending inputs from the brainstem, midbrain, and forebrain nuclei involved in autonomic regulation. The integrated signal is relayed to the adjacent dorsal motor nucleus of the vagus (DMV), which supplies the motor output response via the efferent vagus nerve to regulate and modulate gastric motility, tone, secretion, and emptying, as well as intestinal motility and transit; the precise coordination of these responses is essential for the control of meal size, meal termination, and nutrient absorption. The interconnectivity of the NTS implies that many other CNS areas are capable of modulating vagal efferent output, emphasized by the many CNS disorders associated with dysregulated GI functions including feeding. This review will summarize the role of major CNS centers to gut-related inputs in the regulation of gastric function with specific reference to the regulation of food intake.


Assuntos
Vias Aferentes , Encéfalo/fisiologia , Ingestão de Alimentos , Vias Eferentes , Trato Gastrointestinal/inervação , Trato Gastrointestinal/fisiologia , Tonsila do Cerebelo/fisiologia , Animais , Diabetes Mellitus/fisiopatologia , Hipocampo/fisiologia , Humanos , Hipotálamo/fisiologia , Inflamação/fisiopatologia , Doenças do Sistema Nervoso/fisiopatologia , Obesidade/fisiopatologia , Rombencéfalo/fisiologia , Nervo Vago/fisiologia
8.
Neuromodulation ; 24(7): 1258-1268, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33887080

RESUMO

OBJECTIVES: Constipation and opioid-induced constipation (OIC) are common with limited treatment options. We investigated whether a noninvasive method of auricular vagal nerve stimulation (aVNS) could be used for treating OIC and explored its potential mechanisms and neural pathways in a rodent model of OIC. MATERIALS AND METHODS: Sprague-Dawley were chronically implanted with one pair of auricular electrodes for aVNS. Sixteen rats were treated with loperamide for a week while another 16 rats received bilateral vagotomy, then randomly treated with aVNS or sham-aVNS for a week. In addition, eight normal rats were implanted with a polyethylene catheter in the proximal colon for assessing whole colon transit. RESULTS: 1) The number of fecal pellets and water content in feces increased after aVNS, compared with sham-aVNS. 2) aVNS accelerated colon transit and whole gut transit, compared with sham-aVNS. 3) In colon tissues, aVNS increased the protein expression of choline acetyltransferase, glial cell line-derived neurotrophic factor and the c-kit expression in myenteric interstitial cells of Cajal but decreased the protein expression of neural nitric oxide synthase (p < 0.05 for all, vs. sham-VNS). 4) The prokinetic effects of aVNS were abolished by both subdiaphragmatic vagotomy and atropine. 5) aVNS increased the c-fos expression in both nucleus tractus solitarius and dorsal motor nucleus of vagus, and increased vagal efferent activity (p < 0.05, vs. sham-VNS). CONCLUSIONS: aVNS improves OIC by enhancing colon motility and restoring enteric neural functions mediated via the central and vagal efferent pathway.


Assuntos
Estimulação do Nervo Vago , Analgésicos Opioides , Animais , Colo , Constipação Intestinal/induzido quimicamente , Constipação Intestinal/terapia , Vias Eferentes , Ratos , Ratos Sprague-Dawley , Nervo Vago
9.
Nat Commun ; 12(1): 2449, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907194

RESUMO

In the developing auditory system, spontaneous activity generated in the cochleae propagates into the central nervous system to promote circuit formation. The effects of peripheral firing patterns on spontaneous activity in the central auditory system are not well understood. Here, we describe wide-spread bilateral coupling of spontaneous activity that coincides with the period of transient efferent modulation of inner hair cells from the brainstem medial olivocochlear system. Knocking out α9/α10 nicotinic acetylcholine receptors, a requisite part of the efferent pathway, profoundly reduces bilateral correlations. Pharmacological and chemogenetic experiments confirm that the efferent system is necessary for normal bilateral coupling. Moreover, auditory sensitivity at hearing onset is reduced in the absence of pre-hearing efferent modulation. Together, these results demonstrate how afferent and efferent pathways collectively shape spontaneous activity patterns and reveal the important role of efferents in coordinating bilateral spontaneous activity and the emergence of functional responses during the prehearing period.


Assuntos
Vias Auditivas/fisiologia , Cóclea/fisiologia , Vias Eferentes/fisiologia , Retroalimentação Fisiológica , Receptores Nicotínicos/genética , Estimulação Acústica , Animais , Vias Auditivas/citologia , Cóclea/citologia , Lateralidade Funcional/fisiologia , Expressão Gênica , Células Ciliadas Auditivas Internas/citologia , Células Ciliadas Auditivas Internas/fisiologia , Colículos Inferiores/citologia , Colículos Inferiores/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Núcleo Olivar/citologia , Núcleo Olivar/fisiologia , Receptores Nicotínicos/deficiência
10.
Sci Rep ; 11(1): 9015, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907206

RESUMO

Professional boxers train to reduce their body mass before a match to refine their body movements. To test the hypothesis that the well-defined movements of boxers are represented within the motor loop (cortico-striatal circuit), we first elucidated the brain structure and functional connectivity specific to boxers and then investigated plasticity in relation to boxing matches. We recruited 21 male boxers 1 month before a match (Time1) and compared them to 22 age-, sex-, and body mass index (BMI)-matched controls. Boxers were longitudinally followed up within 1 week prior to the match (Time2) and 1 month after the match (Time3). The BMIs of boxers significantly decreased at Time2 compared with those at Time1 and Time3. Compared to controls, boxers presented significantly higher gray matter volume in the left putamen, a critical region representing motor skill training. Boxers presented significantly higher functional connectivity than controls between the left primary motor cortex (M1) and left putamen, which is an essential region for establishing well-defined movements. Boxers also showed significantly higher structural connectivity in the same region within the motor loop from Time1 to Time2 than during other periods, which may represent the refined movements of their body induced by training for the match.


Assuntos
Boxe , Vias Eferentes/fisiologia , Condicionamento Físico Humano , Putamen/fisiologia , Adulto , Índice de Massa Corporal , Estudos Transversais , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Putamen/anatomia & histologia
11.
J Neurosci ; 41(17): 3842-3853, 2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33737456

RESUMO

Transcranial random noise stimulation (tRNS) over cortical areas has been shown to acutely improve performance in sensory detection tasks. One explanation for this behavioral effect is stochastic resonance (SR), a mechanism that explains how signal processing in nonlinear systems can benefit from added noise. While acute noise benefits of electrical RNS have been demonstrated at the behavioral level as well as in in vitro preparations of neural tissue, it is currently largely unknown whether similar effects can be shown at the neural population level using neurophysiological readouts of human cortex. Here, we hypothesized that acute tRNS will increase the responsiveness of primary motor cortex (M1) when probed with transcranial magnetic stimulation (TMS). Neural responsiveness was operationalized via the well-known concept of the resting motor threshold (RMT). We showed that tRNS acutely decreases RMT. This effect was small, but it was consistently replicated across four experiments including different cohorts (total N = 81, 46 females, 35 males), two tRNS electrode montages, and different control conditions. Our experiments provide critical neurophysiological evidence that tRNS can acutely generate noise benefits by enhancing the neural population response of human M1.SIGNIFICANCE STATEMENT A hallmark feature of stochastic resonance (SR) is that signal processing can benefit from added noise. This has mainly been demonstrated at the single-cell level in vitro where the neural response to weak input signals can be enhanced by simultaneously applying random noise. Our finding that transcranial random noise stimulation (tRNS) acutely increases the excitability of corticomotor circuits extends the principle of noise benefits to the neural population level in human cortex. Our finding is in line with the notion that tRNS might affect cortical processing via the SR phenomenon. It suggests that enhancing the response of cortical populations to an external stimulus might be one neurophysiological mechanism mediating performance improvements when tRNS is applied to sensory cortex during perception tasks.


Assuntos
Estimulação Acústica , Vias Eferentes/fisiologia , Ruído , Limiar Sensorial/fisiologia , Adolescente , Adulto , Algoritmos , Córtex Cerebral/fisiologia , Eletromiografia , Potencial Evocado Motor/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiologia , Sensação , Processos Estocásticos , Estimulação Magnética Transcraniana , Adulto Jovem
12.
Acta Neurochir (Wien) ; 163(5): 1269-1278, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33537863

RESUMO

BACKGROUND: Postoperative motor deficits are among the worst morbidities of glioma surgery. We aim to investigate factors associated with postoperative motor deficits in patients with frontoparietal opercular gliomas. METHODS: Thirty-four patients with frontoparietal opercular gliomas were retrospectively investigated. We examined the postoperative ischemic changes and locations obtained from MRI. RESULTS: Twenty-one patients (62%) presented postoperative ischemic changes. Postoperative MRI was featured with ischemic changes, all located at the subcortical area of the resection cavity. Six patients had postoperative motor deficits, whereas 28 patients did not. Compared to those without motor deficits, those with motor deficits were associated with old age, pre- and postcentral gyri resection, and postcentral gyrus resection (P = 0.023, 0,024, and 0.0060, respectively). A merged image of the resected cavity and T1-weighted brain atlas of the Montreal Neurological Institute showed that a critical area for postoperative motor deficits is the origin of the long insular arteries (LIAs) and the postcentral gyrus. Detail anatomical architecture created by the Human Connectome Project database and T2-weighted images showed that the subcortical area of the operculum of the postcentral gyrus is where the medullary arteries supply, and the motor pathways originated from the precentral gyrus run. CONCLUSIONS: We verified that the origin of the LIAs could damage the descending motor pathways during the resection of frontoparietal opercular gliomas. Also, we identified that motor pathways run the subcortical area of the operculum of the postcentral gyrus, indicating that the postcentral gyrus is an unrecognized area of damaging the descending motor pathways.


Assuntos
Neoplasias Encefálicas/cirurgia , Vias Eferentes/irrigação sanguínea , Vias Eferentes/diagnóstico por imagem , Glioma/cirurgia , Córtex Somatossensorial/cirurgia , Adolescente , Adulto , Idoso , Mapeamento Encefálico , Neoplasias Encefálicas/diagnóstico por imagem , Criança , Vias Eferentes/patologia , Feminino , Glioma/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Período Pós-Operatório , Tratos Piramidais/diagnóstico por imagem , Estudos Retrospectivos , Fatores de Risco , Córtex Somatossensorial/diagnóstico por imagem , Adulto Jovem
14.
J Neurophysiol ; 125(4): 1079-1094, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33566734

RESUMO

A number of notions in the fields of motor control and kinesthetic perception have been used without clear definitions. In this review, we consider definitions for efference copy, percept, and sense of effort based on recent studies within the physical approach, which assumes that the neural control of movement is based on principles of parametric control and involves defining time-varying profiles of spatial referent coordinates for the effectors. The apparent redundancy in both motor and perceptual processes is reconsidered based on the principle of abundance. Abundance of efferent and afferent signals is viewed as the means of stabilizing both salient action characteristics and salient percepts formalized as stable manifolds in high-dimensional spaces of relevant elemental variables. This theoretical scheme has led recently to a number of novel predictions and findings. These include, in particular, lower accuracy in perception of variables produced by elements involved in a multielement task compared with the same elements in single-element tasks, dissociation between motor and perceptual effects of muscle coactivation, force illusions induced by muscle vibration, and errors in perception of unintentional drifts in performance. Taken together, these results suggest that participation of efferent signals in perception frequently involves distorted copies of actual neural commands, particularly those to antagonist muscles. Sense of effort is associated with such distorted efferent signals. Distortions in efference copy happen spontaneously and can also be caused by changes in sensory signals, e.g., those produced by muscle vibration.


Assuntos
Cinestesia/fisiologia , Modelos Teóricos , Atividade Motora/fisiologia , Neurônios Motores/fisiologia , Movimento/fisiologia , Animais , Vias Eferentes/fisiologia , Humanos
15.
Philos Trans R Soc Lond B Biol Sci ; 376(1821): 20190764, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33550954

RESUMO

Discussions of the function of early nervous systems usually focus on a causal flow from sensors to effectors, by which an animal coordinates its actions with exogenous changes in its environment. We propose, instead, that much early sensing was reafferent; it was responsive to the consequences of the animal's own actions. We distinguish two general categories of reafference-translocational and deformational-and use these to survey the distribution of several often-neglected forms of sensing, including gravity sensing, flow sensing and proprioception. We discuss sensing of these kinds in sponges, ctenophores, placozoans, cnidarians and bilaterians. Reafference is ubiquitous, as ongoing action, especially whole-body motility, will almost inevitably influence the senses. Corollary discharge-a pathway or circuit by which an animal tracks its own actions and their reafferent consequences-is not a necessary feature of reafferent sensing but a later-evolving mechanism. We also argue for the importance of reafferent sensing to the evolution of the body-self, a form of organization that enables an animal to sense and act as a single unit. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.


Assuntos
Vias Eferentes/fisiologia , Fenômenos Fisiológicos do Sistema Nervoso , Propriocepção , Animais , Cnidários/fisiologia , Ctenóforos/fisiologia , Sistema Nervoso/química , Placozoa/fisiologia , Poríferos/fisiologia
16.
Oper Neurosurg (Hagerstown) ; 20(5): E379-E385, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33475704

RESUMO

BACKGROUND AND IMPORTANCE: Intraoperative neurophysiological monitoring of the motor pathways during epilepsy surgery is essential to safely achieve maximal resection of the epileptogenic zone. Motor evoked potential (MEP) recording is usually performed intermittently during resection using a handheld stimulator or continuously through an electrode array placed on the motor cortex. We present a novel variation of continuous MEP acquisition through previously implanted depth electrodes in the perirolandic cortex. CLINICAL PRESENTATION: A 60-yr-old woman with a history of a left frontal meningioma (World Health Organization [WHO] grade II) treated with surgical resection and radiation presented with residual right hemiparesis and refractory epilepsy. Imaging demonstrated a perirolandic lesion with surrounding edema and mass effect in the prior surgical site, suspicious for radiation necrosis versus tumor recurrence. Presurgical electrocorticography (ECoG) with orthogonal, stereotactically implanted depth electrodes (stereoelectroencephalography [SEEG]) of the perirolandic cortex captured seizure onsets from the supplementary motor area (SMA) and primary motor cortex (PMC). The patient underwent a left frontal craniotomy for repeat resection and tissue diagnosis. Intraoperative ECoG and MEPs were obtained continuously with direct cortical stimulation through the indwelling SEEG electrodes in the PMC. Maximal resection was achieved with preservation of direct cortical MEPs and without deterioration of her baseline hemiparesis. Biopsy revealed radiation necrosis. At 30-mo follow-up, the patient had only rare seizures (Engel class IIB). CONCLUSION: Intraoperative cortical MEP acquisition through implanted SEEG electrode arrays is a potentially safe and effective alternative approach to continuously monitor the motor pathways during the resection of a perirolandic epileptogenic lesion, without the need for surgical interruptions.


Assuntos
Monitorização Neurofisiológica Intraoperatória , Vias Eferentes , Eletrodos Implantados , Eletroencefalografia , Feminino , Humanos , Recidiva Local de Neoplasia
17.
Ann Otol Rhinol Laryngol ; 130(9): 1004-1009, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33491463

RESUMO

OBJECTIVE: To record crossed acoustic reflex thresholds (xART's) postoperatively from patients after surgical repair of unilateral congenital aural atresia (CAA). To seek explanations for when xARTs can and cannot be recorded. We hope to understand the implications for this central auditory reflex despite early afferent deprivation. METHODS: Patients who underwent surgery to correct unilateral CAA at a tertiary academic medical were prospectively enrolled to evaluate for the presence of xART. Preoperative ARTs in the normal (non-atretic) ear, and postoperative ipsilateral ARTs (stimulus in the normal ear) and contralateral ARTs (stimulus in the newly reconstructed atretic ear; record in the normal ear) were measured at 500, 1000, and 2000 Hz. RESULTS: Four of 11 patients with normal ipsilateral reflex thresholds preoperatively demonstrated crossed acoustic reflexes postoperatively (stimulus in reconstructed ear; record from normal ear). Four other patients demonstrated normal ipsilateral thresholds preoperatively but did not have crossed reflexes postoperatively. No reflexes (pre- or postoperatively) could be recorded in 3 patients. Crossed reflex threshold is significantly correlated with the postoperative audiometric threshold. There was no correlation between ipsilateral and contralateral reflex thresholds. CONCLUSION: Crossed acoustic reflexes can be recorded from some but not all postoperative atresia patients, and the thresholds for those reflexes correlate with the postoperative pure tone threshold. The presence of acoustic reflexes implies an intact CN VIII-to-opposite CN VII central reflex arc despite early unilateral sound deprivation.


Assuntos
Vias Auditivas/fisiopatologia , Anormalidades Congênitas/fisiopatologia , Orelha/anormalidades , Vias Eferentes/fisiopatologia , Nervo Facial/fisiopatologia , Reflexo Acústico/fisiologia , Nervo Vestibulococlear/fisiopatologia , Audiometria de Tons Puros , Limiar Auditivo , Criança , Anormalidades Congênitas/cirurgia , Orelha/fisiopatologia , Orelha/cirurgia , Vias Eferentes/fisiologia , Nervo Facial/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Substituição Ossicular , Procedimentos Cirúrgicos Otológicos , Estudos Prospectivos , Nervo Vestibulococlear/fisiologia
18.
Int J Audiol ; 60(9): 677-686, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33426967

RESUMO

OBJECTIVE: The medial olivocochlear (MOC) reflex provides efferent feedback from the brainstem to cochlear outer hair cells. Physiologic studies have demonstrated that the MOC reflex is involved in "unmasking" of signals-in-noise at the level of the auditory nerve; however, its functional importance in human hearing remains unclear. DESIGN: This study examined relationships between pre-neural measurements of MOC reflex strength (click-evoked otoacoustic emission inhibition; CEOAE) and neural measurements of speech-in-noise encoding (speech frequency following response; sFFR) in four conditions (Quiet, Contralateral Noise, Ipsilateral Noise, and Ipsilateral + Contralateral Noise). Three measures of CEOAE inhibition (amplitude reduction, effective attenuation, and input-output slope inhibition) were used to quantify pre-neural MOC reflex strength. Correlations between pre-neural MOC reflex strength and sFFR "unmasking" (i.e. response recovery from masking effects with activation of the MOC reflex in time and frequency domains) were assessed. STUDY SAMPLE: 18 young adults with normal hearing. RESULTS: sFFR unmasking effects were insignificant, and there were no correlations between pre-neural MOC reflex strength and sFFR unmasking in the time or frequency domain. CONCLUSION: Our results do not support the hypothesis that the MOC reflex is involved in speech-in-noise neural encoding, at least for features that are represented in the sFFR at the SNR tested.


Assuntos
Cóclea , Núcleo Olivar , Estimulação Acústica , Vias Eferentes , Humanos , Ruído/efeitos adversos , Emissões Otoacústicas Espontâneas , Fala
19.
Neurosci Lett ; 745: 135621, 2021 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-33421491

RESUMO

The Basolateral amygdala (BLA) and central nucleus of the amygdala (CEA) have been proved to play a key role in the control of anxiety, stress and fear-related behaviors. BLA is a cortex-like complex consisting of both γ-aminobutyric acidergic (GABAergic) interneurons and glutamatergic neurons. The CEA is a striatum-like output of the amygdala, consisting almost exclusively of GABAergic medium spiny neurons. In this study, we explored the morphology and axonal projections of the GABAergic neurons in BLA and CEA, using conditional anterograde axonal tracing, immunohistochemistry, and VGAT-Cre transgenic mice to further understand their functional roles. We found that the axonal projections of GABAergic neurons from the BLA mainly distributed to the forebrain, whilst GABAergic neurons from the CEA distributed to the forebrain, midbrain and brainstem. In the forebrain, the axonal projections of GABAergic neurons from the BLA projected to the anterior olfactory nucleus, the cerebral cortex, the septum, the striatum, the thalamus, the amygdala and the hippocampus. The axonal projections of GABAergic neurons from the CEA distributed to the nuclei of the prefrontal cortex, the bed nucleus of the stria terminalis, the hypothalamus and the thalamus. In the midbrain and brainstem, the axonal projections of GABAergic neurons from the CEA were found in the periaqueductal gray, the substantia nigra, and the locus coeruleus. These data reveal the neuroanatomical basis for exploring the function of GABAergic neurons in the BLA and CEA, particularly during the processing of fear-related behavior.


Assuntos
Complexo Nuclear Basolateral da Amígdala/fisiologia , Núcleo Central da Amígdala/fisiologia , Vias Eferentes/fisiologia , Neurônios GABAérgicos/fisiologia , Animais , Complexo Nuclear Basolateral da Amígdala/química , Núcleo Central da Amígdala/química , Vias Eferentes/química , Neurônios GABAérgicos/química , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos
20.
J Neurosci ; 41(1): 47-60, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33203744

RESUMO

The lateral line (LL) is a sensory system that allows fish and amphibians to detect water currents. LL responsiveness is modulated by efferent neurons that aid in distinguishing between external and self-generated stimuli, maintaining sensitivity to relevant cues. One component of the efferent system is cholinergic, the activation of which inhibits afferent activity. LL hair cells (HCs) share structural, functional, and molecular similarities with those of the cochlea, making them a popular model for studying human hearing and balance disorders. Because of these commonalities, one could propose that the receptor at the LL efferent synapse is a α9α10 nicotinic acetylcholine receptor (nAChR). However, the identities of the molecular players underlying ACh-mediated inhibition in the LL remain unknown. Surprisingly, through the analysis of single-cell expression studies and in situ hybridization, we describe that α9, but not the α10, subunits are enriched in zebrafish HCs. Moreover, the heterologous expression of zebrafish α9 subunits indicates that homomeric receptors are functional and exhibit robust ACh-gated currents blocked by α-bungarotoxin and strychnine. In addition, in vivo Ca2+ imaging on mechanically stimulated zebrafish LL HCs show that ACh elicits a decrease in evoked Ca2+ signals, regardless of HC polarity. This effect is blocked by both α-bungarotoxin and apamin, indicating coupling of ACh-mediated effects to small-conductance Ca2+-activated potassium (SKs) channels. Our results indicate that an α9-containing (α9*) nAChR operates at the zebrafish LL efferent synapse. Moreover, the activation of α9* nAChRs most likely leads to LL HC hyperpolarization served by SK channels.SIGNIFICANCE STATEMENT The fish lateral line (LL) mechanosensory system shares structural, functional, and molecular similarities with those of the mammalian cochlea. Thus, it has become an accessible model for studying human hearing and balance disorders. However, the molecular players serving efferent control of LL hair cell (HC) activity have not been identified. Here we demonstrate that, different from the hearing organ of vertebrate species, a nicotinic acetylcholine receptor composed only of α9 subunits operates at the LL efferent synapse. Activation of α9-containing receptors leads to LL HC hyperpolarization because of the opening of small-conductance Ca2+-activated potassium channels. These results will further aid in the interpretation of data obtained from LL HCs as a model for cochlear HCs.


Assuntos
Vias Eferentes/fisiologia , Sistema da Linha Lateral/fisiologia , Sistema Nervoso Parassimpático/fisiologia , Sinapses/fisiologia , Animais , Bungarotoxinas/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Regulação da Expressão Gênica , Células Ciliadas Auditivas/fisiologia , Antagonistas Nicotínicos/farmacologia , Oócitos , Estimulação Física , Receptores Nicotínicos/efeitos dos fármacos , Canais de Potássio Ativados por Cálcio de Condutância Baixa/efeitos dos fármacos , Estricnina/farmacologia , Xenopus , Peixe-Zebra
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