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2.
Arq Neuropsiquiatr ; 79(10): 900-903, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34706020

RESUMO

BACKGROUND: Pruritus is a common complaint in dermatology. Wartenberg, in 1943, associated pruritus with neuropathy, relating it to the "posterior antebrachial cutaneous nerve neuropathy". In 1968, Waisman described patients with frequent pruritus complaints in the upper limb during the summer, which he named "brachioradial summer pruritus". Currently, this pruritus is named brachioradial pruritus (BRP). BRP is characterized by a chronic pruritus, usually localized, with a long duration, and without apparent cutaneous abnormalities. Neurological disorders both from the central and peripheral nervous systems, including multiple sclerosis, are associated with pruritus. OBJECTIVE: To investigate correlations between symptomatic dermatomes and alterations in the myotomes, as evidenced by electroneuromyography (ENMG). METHODS: Forty-six patients with BRP dermatological diagnoses were subjected to upper limb ENMG. RESULTS: Among 46 patients with C5 to C8 dermatomal pruritus, we evaluated 113 symptomatic dermatomal areas. Overall, 39 (85%) patients had radicular involvement and 28 (60%) had agreement between complaint and the ENMG findings (p=0.015). A total of 80% of the patients with complaints at C7 and 47% at C6 had radicular involvement at the same level. CONCLUSIONS: Among the patients who presented complaints, 47 and 80%, respectively, had ENMG alterations in the C6 and C7 myotomes. We conclude that peripheral nervous system involvement is associated with BRP.


Assuntos
Doenças do Sistema Nervoso , Prurido , Antebraço , Humanos , Masculino , Neurofisiologia , Prurido/etiologia , Pele
3.
Arq Neuropsiquiatr ; 79(10): 912-923, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34706022

RESUMO

BACKGROUND: Adult-onset spinal muscular atrophy (SMA) represents an expanding group of inherited neurodegenerative disorders in clinical practice. OBJECTIVE: This review aims to synthesize the main clinical, genetic, radiological, biochemical, and neurophysiological aspects related to the classical and recently described forms of proximal SMA. METHODS: The authors performed a non-systematic critical review summarizing adult-onset proximal SMA presentations. RESULTS: Previously limited to cases of SMN1-related SMA type 4 (adult form), this group has now more than 15 different clinical conditions that have in common the symmetrical and progressive compromise of lower motor neurons starting in adulthood or elderly stage. New clinical and genetic subtypes of adult-onset proximal SMA have been recognized and are currently target of wide neuroradiological, pathological, and genetic studies. CONCLUSIONS: This new complex group of rare disorders typically present with lower motor neuron disease in association with other neurological or systemic signs of impairment, which are relatively specific and typical for each genetic subtype.


Assuntos
Doença dos Neurônios Motores , Atrofia Muscular Espinal , Radiologia , Adulto , Humanos , Atrofia Muscular Espinal/genética , Neurofisiologia , Doenças Raras
4.
Nat Commun ; 12(1): 6043, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34654817

RESUMO

Clinical evidence has established that concomitant traumatic brain injury (TBI) accelerates bone healing, but the underlying mechanism is unclear. This study shows that after TBI, injured neurons, mainly those in the hippocampus, release osteogenic microRNA (miRNA)-enriched small extracellular vesicles (sEVs), which targeted osteoprogenitors in bone to stimulate bone formation. We show that miR-328a-3p and miR-150-5p, enriched in the sEVs after TBI, promote osteogenesis by directly targeting the 3'UTR of FOXO4 or CBL, respectively, and hydrogel carrying miR-328a-3p-containing sEVs efficiently repaires bone defects in rats. Importantly, increased fibronectin expression on sEVs surface contributes to targeting of osteoprogenitors in bone by TBI sEVs, thereby implying that modification of the sEVs surface fibronectin could be used in bone-targeted drug delivery. Together, our work unveils a role of central regulation in bone formation and a clear link between injured neurons and osteogenitors, both in animals and clinical settings.


Assuntos
Osso e Ossos/metabolismo , Osso e Ossos/patologia , Lesões Encefálicas/metabolismo , Lesões Encefálicas/patologia , Encéfalo/metabolismo , Vesículas Extracelulares/metabolismo , Cicatrização , Adolescente , Adulto , Idoso , Animais , Linhagem Celular , Modelos Animais de Doenças , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Humanos , Masculino , MicroRNAs/genética , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurofisiologia , Osteogênese , Proteômica , Ratos , Doenças Reumáticas , Cicatrização/genética , Adulto Jovem
5.
Nat Commun ; 12(1): 5713, 2021 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-34588439

RESUMO

Large, openly available datasets and current analytic tools promise the emergence of population neuroscience. The considerable diversity in personality traits and behaviour between individuals is reflected in the statistical variability of neural data collected in such repositories. Recent studies with functional magnetic resonance imaging (fMRI) have concluded that patterns of resting-state functional connectivity can both successfully distinguish individual participants within a cohort and predict some individual traits, yielding the notion of an individual's neural fingerprint. Here, we aim to clarify the neurophysiological foundations of individual differentiation from features of the rich and complex dynamics of resting-state brain activity using magnetoencephalography (MEG) in 158 participants. We show that akin to fMRI approaches, neurophysiological functional connectomes enable the differentiation of individuals, with rates similar to those seen with fMRI. We also show that individual differentiation is equally successful from simpler measures of the spatial distribution of neurophysiological spectral signal power. Our data further indicate that differentiation can be achieved from brain recordings as short as 30 seconds, and that it is robust over time: the neural fingerprint is present in recordings performed weeks after their baseline reference data was collected. This work, thus, extends the notion of a neural or brain fingerprint to fast and large-scale resting-state electrophysiological dynamics.


Assuntos
Encéfalo/fisiologia , Individualidade , Magnetoencefalografia/estatística & dados numéricos , Neurofisiologia/métodos , Descanso/fisiologia , Adolescente , Adulto , Artefatos , Conectoma , Fenômenos Eletrofisiológicos , Feminino , Humanos , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , Adulto Jovem
6.
J Neurosci Methods ; 364: 109370, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34562523

RESUMO

BACKGROUND: Much progress has been made at the interface between neural tissue and electrodes for neurophysiology. However, there continues to be a need for novel materials that integrate well with the nervous system and facilitate neural recordings with longer-term sustainability and stability. Such materials have the potential to improve clinical approaches and provide important tools for basic neuroscience research. NEW METHOD: In this paper, we explore the use of dry-spun untreated or functionalized carbon nanotube fibers as implantable electrodes for neural recordings from insects over extended time periods. RESULTS: Measurements of fly eyes responding to light flashes illustrate the suitability of these materials for recording both the low- and high-frequency components of neural signals. Repeated recordings show good sustainability, especially with functionalized carbon nanotube fibers. In particular, recordings from the optic lobes of Madagascar hissing cockroaches last for at least 8 weeks. COMPARISON WITH EXISTING METHOD(S): Electrophysiological research continues to rely heavily on metal electrodes that are good for short-lived preparations but less suitable for longer-term recordings, as scar tissue formation and cytotoxicity tend to cause a gradual reduction in signals. CONCLUSIONS: Functionalized carbon nanotubes are a promising novel material that can be used to obtain long-term or repeated stable recordings, which are necessary for longitudinal studies, or to maintain other neural tissue interfaces such as those in insect-machine hybrid robots. The introduced insect preparation can also be used for the relatively rapid and cost-efficient testing of novel electrode materials.


Assuntos
Nanotubos de Carbono , Fibra de Carbono , Eletrodos Implantados , Neurônios , Neurofisiologia
7.
Adv Physiol Educ ; 45(4): 702-708, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34498935

RESUMO

Patch-clamp electrophysiological recordings of neuronal activity require a large amount of space and equipment. The technique is difficult to master and not conducive to demonstration to more than a few medical students. Therefore, neurophysiological education is mostly limited to classroom-based pedagogies such as lectures. However, the demonstration of concepts such as changes in membrane potential and ion channel activity is best achieved with hands-on approaches. This article details an in silico activity suitable for large groups of medical students that demonstrates the key concepts in neurophysiology using the LabAXON simulation software. Learning activities in our practical include 1) measurements of voltage and time parameters of the neuronal action potential and its relationship to the Nernst potentials of Na+ and K+; 2) determination of the stimulus threshold to evoke action potentials; 3) demonstration of the refractory period of an action potential; and 4) voltage-clamp experiments to determine the current-voltage relationship of voltage-gated Na+ and K+ channels and the voltage dependence of, and recovery from, inactivation of voltage-gated Na+ channels. We emphasized the accuracy of quantitative measurements as well as the correct use of units. The level of difficulty of the activity can be altered through different multiple choice questions relating to material introduced in the associated lectures. This practical activity is suitable for different class sizes and is adaptable for delivery with online platforms. Student feedback showed that the students felt the activity helped them consolidate their understanding of the lecture material.


Assuntos
Neurofisiologia , Estudantes de Medicina , Potenciais de Ação , Humanos , Potenciais da Membrana , Sódio
8.
Comput Intell Neurosci ; 2021: 9954302, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539774

RESUMO

Neurophysiological studies have shown that there is a close relationship between spikes and local field potential (LFP), which reflects crucial neural coding information. In this paper, we used a new method to evaluate the synchronization between spikes and LFP. All possible phases of LFP from -π to π were first binned into a freely chosen number of bins; then, the probability of spikes falling in each bin was calculated, and the deviation degree from the uniform distribution based on the Kullback-Leibler divergence was calculated to define the synchronization between spikes and LFP. The simulation results demonstrate that the method is rapid, basically unaffected by the total number of spikes, and can adequately resist the noise of spike trains. We applied this method to the experimental data of patients with intractable epilepsy, and we observed the synchronization between spikes and LFP in the formation of memory. These results show that our proposed method is a powerful tool that can quantitatively measure the synchronization between spikes and LFP.


Assuntos
Neurônios , Neurofisiologia , Potenciais de Ação , Simulação por Computador , Humanos
10.
J Neurosci Methods ; 363: 109323, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34391792

RESUMO

BACKGROUND: Peripheral neuropathy treatment is not always satisfactory. To fill this gap, inferences from bench side are warranted, where morphological and pathogenetic determinations can be performed. Nerve conduction studies (NCS) are ideal to translate results from preclinical to clinical setting. NEW METHODS: We propose a comprehensive 8-minute protocol for sensory-motor neurophysiological assessment, similar to routine clinical practice: sensory proximal and distal caudal nerves, motor caudal nerve, and sensory digital nerve recordings were used and tested in 2 different experimental settings. In Experiment 1 we compared control (CTRL) animals to a severe sensory-motor polyneuropathy (animals treated with vincristine [VCR]), and in Experiment 2 CTRL animals were compared to a mild sensory polyneuropathy (animals treated with oxaliplatin [OHP]). NCS were performed after 1-month of chemotherapy and matched with confirmatory neuropathological analyses. RESULTS: VCR treated animals showed, at NCS, a relevant sensory-motor polyneuropathy ensued at the end of treatment; whereas, OHP animals showed a mild distal sensory neuropathy. These patterns were confirmed by neuropathological analysis. COMPARISON WITH EXISTING METHODS: In literature, the majority of proposed neurophysiological protocols relies mainly on a single nerve testing, rather than a combination of them, and only a few studies tested both caudal and sciatic nerve branches, nevertheless not aiming at fully reproduce clinical protocols (e.g., seeking for length-dependency); to provide evidence of appropriateness of our protocol we applied a gold standard: neuropathology. CONCLUSION: The simple and rapid protocol here presented can be suggested as a good translation outcome measure in preclinical setting.


Assuntos
Condução Nervosa , Doenças do Sistema Nervoso Periférico , Animais , Neurofisiologia , Nervos Periféricos , Doenças do Sistema Nervoso Periférico/tratamento farmacológico
11.
Neuron ; 109(19): 3055-3068, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34416170

RESUMO

A major shift is happening within neurophysiology: a population doctrine is drawing level with the single-neuron doctrine that has long dominated the field. Population-level ideas have so far had their greatest impact in motor neuroscience, but they hold great promise for resolving open questions in cognition as well. Here, we codify the population doctrine and survey recent work that leverages this view to specifically probe cognition. Our discussion is organized around five core concepts that provide a foundation for population-level thinking: (1) state spaces, (2) manifolds, (3) coding dimensions, (4) subspaces, and (5) dynamics. The work we review illustrates the progress and promise that population-level thinking holds for cognitive neuroscience-for delivering new insight into attention, working memory, decision-making, executive function, learning, and reward processing.


Assuntos
Neurociência Cognitiva/tendências , Neurofisiologia/tendências , População , Animais , Humanos
12.
Adv Physiol Educ ; 45(3): 594-598, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34379484

RESUMO

"Basic Concepts in Neurophysiology" was a 3-wk online course developed during six synchronous meetings combined with asynchronous activities. We proposed an active learning course that used free online platforms to teach physiology during a period in which undergraduates were not in classrooms or taking online classes due to the COVID-19 pandemic. Herein, we report the course organization and the students' involvement in, acceptance of, and evaluation of the course. To address the students' perceptions about these points, we sent a questionnaire to 49 participants who finished the course. We found that although most students (52.5%) had never taken a course with similar methods before, almost all of them (95%) liked the flipped class model. Additionally, a majority of the students (92.5%) said that the method increased their study frequency during the social distancing period, which is an important aspect to consider during this challenging time for both students and professors.


Assuntos
COVID-19 , Pandemias , Humanos , Neurofisiologia , Quarentena , SARS-CoV-2
14.
Clin Neurophysiol ; 132(9): 2248-2250, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34275732

RESUMO

Restructuring of healthcare services during the COVID-19 pandemic has led to lockdown of Epilepsy Monitoring Units (EMUs) in many hospitals. The ad-hoc taskforce of the International League Against Epilepsy (ILAE) and the International Federation of Clinical Neurophysiology (IFCN) highlights the detrimental effect of postponing video-EEG monitoring of patients with epilepsy and other paroxysmal events. The taskforce calls for action to continue functioning of Epilepsy Monitoring Units during emergency situations, such as the COVID-19 pandemic. Long-term video-EEG monitoring is an essential diagnostic service. Access to video-EEG monitoring of the patients in the EMUs must be given high priority. Patients should be screened for COVID-19, before admission, according to the local regulations. Local policies for COVID-19 infection control should be adhered to during the video-EEG monitoring. In cases of differential diagnosis where reduction of antiseizure medication is not required, consider home video-EEG monitoring as an alternative in selected patients.


Assuntos
COVID-19/prevenção & controle , Controle de Doenças Transmissíveis/normas , Eletroencefalografia/normas , Epilepsia/diagnóstico , Acesso aos Serviços de Saúde/normas , Neurofisiologia/normas , COVID-19/epidemiologia , Controle de Doenças Transmissíveis/métodos , Consenso , Eletroencefalografia/métodos , Epilepsia/epidemiologia , Epilepsia/fisiopatologia , Humanos , Internacionalidade , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Neurofisiologia/métodos
15.
J Neurosci Methods ; 361: 109286, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34242704

RESUMO

BACKGROUND: Electrical probes have been widely used for recording single-unit spike activity and local field potentials (LFPs) in brain regions. However, setting up an easily-assembled large-scale recording in multiple brain regions for long-term and stable neural activity monitoring is still a hard task. NEW METHOD: We established a novel 3D-printed multi-drive system with high-density (up to 256 channels) tetrodes/grid electrodes that enables us to record cortical and subcortical brain regions in freely behaving animals. RESULTS: In this paper, we described the design and fabrication of this system in detail. By using this system, we obtained successful recording on both spikes and LFPs from seven distinct brain regions that are related to memory function. COMPARISION WITH EXISTING METHODS: The low cost, large-scale electrodes with small size and flexible 3D-printed design of the system allow us to implant assembled tetrodes or grid electrodes into multiple target brain areas. CONCLUSIONS: The 3D-printed large-scale multi-drive platform we described here may serve as a powerful new tool for future studies of brain circuitry functions.


Assuntos
Encéfalo , Neurofisiologia , Animais , Eletrodos Implantados , Memória , Impressão Tridimensional
17.
Eur J Neurol ; 28(11): 3768-3773, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34233056

RESUMO

BACKGROUND AND PURPOSE: In its initial stages, Guillain-Barré syndrome (GBS) is difficult to identify, because diagnostic criteria may not always be fulfilled. With this retrospective study, we wanted to identify the most common electrophysiological abnormalities seen on neurophysiological examination of GBS patients and its variants in the early phases. METHODS: We reviewed the clinical records of patients admitted to our Neurology Unit with a confirmed diagnosis of GBS. The study sample was divided in two subgroups according to whether the neurophysiological examination was performed: within 7 days (very early group) or within 7-15 days (early group). H reflex, F waves, and motor and sensory conduction parameters were judged abnormal if they were outside the normal range for at least two nerves. We evaluated neurophysiological findings in Miller-Fisher syndrome (MFS) separately. RESULTS: The study sample comprised 36 patients. In GBS, the most frequent abnormal neurophysiological parameter was the bilateral absence of the H reflex, followed by F wave abnormalities. Motor conduction parameters were altered in less than 50% of patients, and even less common were sensory nerve action potential reduction and the "sural-sparing" pattern. In MFS, H reflex was absent bilaterally in 100% of patients, followed by a predominant peripheral sensory involvement, whereas motor conduction parameters were frequently normal. CONCLUSIONS: Bilateral absence of the H reflex is the most sensitive parameter in early diagnosis of GBS and its variants.


Assuntos
Síndrome de Guillain-Barré , Síndrome de Miller Fisher , Síndrome de Guillain-Barré/diagnóstico , Frequência Cardíaca , Humanos , Condução Nervosa , Neurofisiologia , Estudos Retrospectivos
18.
Sci Rep ; 11(1): 15525, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34330935

RESUMO

This paper deals with the information transfer mechanisms underlying causal relations between brain regions under resting condition. fMRI images of a large set of healthy individuals from the 1000 Functional Connectomes Beijing Zang dataset have been considered and the causal information transfer among brain regions studied using Transfer Entropy concepts. Thus, we explored the influence of a set of states in two given regions at time t (At Bt.) over the state of one of them at a following time step (Bt+1) and could observe a series of time-dependent events corresponding to four kinds of interactions, or causal rules, pointing to (de)activation and turn off mechanisms and sharing some features with positive and negative functional connectivity. The functional architecture emerging from such rules was modelled by a directional multilayer network based upon four interaction matrices and a set of indexes describing the effects of the network structure in several dynamical processes. The statistical significance of the models produced by our approach was checked within the used database of homogeneous subjects and predicts a successful extension, in due course, to detect differences among clinical conditions and cognitive states.


Assuntos
Encéfalo/fisiologia , Entropia , Humanos , Neurofisiologia , Neurociências
19.
Nat Commun ; 12(1): 4352, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34272368

RESUMO

It is unclear how different types of cortical projection neurons work together to support diverse cortical functions. We examined the discharge characteristics and inactivation effects of intratelencephalic (IT) and pyramidal tract (PT) neurons-two major types of cortical excitatory neurons that project to cortical and subcortical structures, respectively-in the deep layer of the medial prefrontal cortex in mice performing a delayed response task. We found stronger target-dependent firing of IT than PT neurons during the delay period. We also found the inactivation of IT neurons, but not PT neurons, impairs behavioral performance. In contrast, PT neurons carry more temporal information than IT neurons during the delay period. Our results indicate a division of labor between IT and PT projection neurons in the prefrontal cortex for the maintenance of working memory and for tracking the passage of time, respectively.


Assuntos
Comportamento Animal/fisiologia , Memória de Curto Prazo/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia , Animais , Técnicas de Introdução de Genes , Interneurônios/fisiologia , Camundongos , Camundongos Transgênicos , Neurofisiologia , Optogenética , Análise de Componente Principal , Células Piramidais/fisiologia , Fatores de Tempo
20.
Oper Neurosurg (Hagerstown) ; 21(3): E180-E186, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34133746

RESUMO

BACKGROUND: Precise targeting of cortical surface electrodes to epileptogenic regions defined by anatomic and electrophysiological guideposts remains a surgical challenge during implantation of responsive neurostimulation (RNS) devices. OBJECTIVE: To describe a hybrid fluoroscopic and neurophysiological technique for targeting of subdural cortical surface electrodes to anatomic regions with limited direct visualization, such as the interhemispheric fissure. METHODS: Intraoperative two-dimensional (2D) fluoroscopy was used to colocalize and align an electrode for permanent device implantation with a temporary in Situ electrode placed for extraoperative seizure mapping. Intraoperative phase reversal mapping technique was performed to distinguish primary somatosensory and motor cortex. RESULTS: We applied these techniques to optimize placement of an interhemispheric strip electrode connected to a responsive neurostimulator system for detection and treatment of seizures arising from a large perirolandic cortical malformation. Intraoperative neuromonitoring (IONM) phase reversal technique facilitated neuroanatomic mapping and electrode placement. CONCLUSION: In challenging-to-access anatomic regions, fluoroscopy and intraoperative neurophysiology can be employed to augment targeting of neuromodulation electrodes to the site of seizure onset zone or specific neurophysiological biomarkers of clinical interest while minimizing brain retraction.


Assuntos
Córtex Motor , Neurofisiologia , Eletrodos Implantados , Fluoroscopia , Humanos , Espaço Subdural
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