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1.
Ann Anat ; 239: 151835, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34562604

RESUMO

BACKGROUND: Diaphragm pacing allows certain ventilator-dependent patients to achieve weaning from mechanical ventilation. The reference method consists in implanting intrathoracic contact electrodes around the phrenic nerve during video-assisted thoracic surgery, which involves time-consuming phrenic nerve dissection with a risk of nerve damage. Identifying a phrenic segment suitable for dissection-free implantation of electrodes would constitute progress. STUDY DESIGN: This study characterizes a free terminal phrenic segment never fully described before. We conducted a cadaver study (n = 14) and a clinical observational study during thoracic procedures (n = 54). RESULTS: A free terminal phrenic segment was observed on both sides in 100% of cases, "jumping" from the pericardium to the diaphragm and measuring 60 mm [95% confidence interval; 48-63] and 72.5 mm [65-82] (right left, respectively; p = 0.0038; cadaver study). This segment rolled up on itself at end-expiration and became unravelled and elongated with diaphragm descent (clinical study). Three categories of fat pads were defined (type 1: pericardiophrenic bundle free of surrounding fat; type 2: single fatty fringe leaving the phrenic nerve visible until diaphragmatic entry; type 3: multiple fatty fringes masking the site of penetration of the phrenic nerve) that depended on body mass index (p = 0.001, clinical study). Hematoxylin-eosin and toluidine blue staining (cadaver study) showed that all of the phrenic fibers in the distal, pre-branching part of the terminal segment were contained within a single epineurium containing a variable number of fascicles (right: 1 [95%CI 0.65-4.01]; left 5 [3.37-7.63]; p = 0.03). CONCLUSION: Diaphragm pacing through periphrenic electrodes positioned on the terminal phrenic segment should be tested.


Assuntos
Diafragma , Nervo Frênico , Cadáver , Eletrodos Implantados , Humanos , Pericárdio , Nervo Frênico/anatomia & histologia
2.
Sensors (Basel) ; 21(21)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34770527

RESUMO

Peripheral Nerve Stimulation (PNS) is a promising approach in functional restoration following neural impairments. Although it proves to be advantageous in the number of implantation sites provided compared with intramuscular or epimysial stimulation and the fact that it does not require daily placement, as is the case with surface electrodes, the further advancement of PNS paradigms is hampered by the limitation of spatial selectivity due to the current spread and variations of nerve physiology. New electrode designs such as the Transverse Intrafascicular Multichannel Electrode (TIME) were proposed to resolve this issue, but their use was limited by a lack of innovative multichannel stimulation devices. In this study, we introduce a new portable multichannel stimulator-called STIMEP-and implement different stimulation protocols in rats to test its versatility and unveil the potential of its combined use with TIME electrodes in rehabilitation protocols. We developed and tested various stimulation paradigms in a single fascicle and thereafter implanted two TIMEs. We also tested its stimulation using two different waveforms. The results highlighted the versatility of this new stimulation device and advocated for the parameterizing of a hyperpolarizing phase before depolarization as well as the use of small pulse widths when stimulating with multiple electrodes.


Assuntos
Estimulação Elétrica , Animais , Eletrodos , Eletrodos Implantados , Ratos
3.
Vestn Otorinolaringol ; 86(5): 42-47, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34783472

RESUMO

Sensoneural hearing loss is a polyetiological disease, which is often a secondary reflection of systemic pathology and is associated with damage of the cochlea and auditory nerve receptors. An important point in the surgical stage of cochlear implantation is the introduction of an implant active electrode into the cochleostomy spiral channel through the cochleostoma or round window. However, the issue of intra-cochlear structures surgical trauma in such surgical intervention seems to be very important, as it may reduce the success of subsequent rehabilitation. Therefore, the study of the anatomy of the round window and adjuscent areas was the objective of this work.


Assuntos
Implante Coclear , Implantes Cocleares , Perda Auditiva , Cóclea/cirurgia , Eletrodos Implantados , Humanos , Janela da Cóclea/cirurgia
5.
Artigo em Inglês | MEDLINE | ID: mdl-34705653

RESUMO

Retinal prostheses are biomedical devices that directly utilize electrical stimulation to create an artificial vision to help patients with retinal diseases such as retinitis pigmentosa. A major challenge in the microelectrode array (MEA) design for retinal prosthesis is to have a close topographical fit on the retinal surface. The local retinal topography can cause the electrodes in certain areas to have gaps up to several hundred micrometers from the retinal surface, resulting in impaired, or totally lost electrode functions in specific areas of the MEA. In this manuscript, an MEA with dynamically controlled electrode positions was proposed to reduce the electrode-retina distance and eliminate areas with poor contact after implantation. The MEA prototype had a polydimethylsiloxane and polyimide hybrid flexible substrate with gold interconnect lines and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate electrodes. Ring shaped counter electrodes were placed around the main electrodes to measure the distance between the electrode and the model retinal surface in real time. The results showed that this MEA design could reduce electrode-retina distance up to [Formula: see text] with 200 kPa pressure. Meanwhile, the impedance between the main and counter electrodes increased with smaller electrode-model retinal surface distance. Thus, the change of electrode-counter electrode impedance could be used to measure the separation gap and to confirm successful electrode contact without the need of optical coherence tomography scan. The amplitude of the stimulation signal on the model retinal surface with originally poor contact could be significantly improved after pressure was applied to reduce the gap.


Assuntos
Próteses Visuais , Estimulação Elétrica , Eletrodos Implantados , Humanos , Microeletrodos , Retina , Tomografia de Coerência Óptica
6.
Rev Assoc Med Bras (1992) ; 67(6): 816-821, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34709323

RESUMO

OBJECTIVE: Use Lead-DBS software to analyze stereotactical surgical outcome of an operated population and demonstrate that small target deviations do not compromise the stimulation of desired structures, even with small amperages. METHODS: Image exams of patients submitted to deep brain stimulation for movement disorders treatment were processed in Lead-DBS software. Electrode stereotactic coordinates were subtracted from the planned target and those deviations, compared among different anatomical targets and sides operated firstly and secondly. We also quantified the frequency of relation between the activated tissue volume and the planned target through computer simulations. RESULTS: None of the 16 electrodes were exactly implanted at the planned coordinates. A stimulation of 3 mA reached 62.5% of the times the planned coordinates, rising to 68.75% with a 3,5 mA. No statistical significance was demonstrated in any comparison of laterality and anatomical sites. CONCLUSIONS: The simulation of small amperage fields could reach the intended target even when electrode placement is suboptimal. Furthermore, such a goal can be achieved without overlapping the volume of activated tissue with undesired structures. Software Lead-DBS proved to be a valuable complementary asset for surgical stereotactical result assessment.


Assuntos
Estimulação Encefálica Profunda , Eletrodos Implantados , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Motivação
7.
J Neural Eng ; 18(5)2021 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-34607318

RESUMO

Objective.Electrocorticography (ECoG) based brain-computer interfaces (BCIs) can be used to restore communication in individuals with locked-in syndrome. In motor-based BCIs, the number of degrees-of-freedom, and thus the speed of the BCI, directly depends on the number of classes that can be discriminated from the neural activity in the sensorimotor cortex. When considering minimally invasive BCI implants, the size of the subdural ECoG implant must be minimized without compromising the number of degrees-of-freedom.Approach.Here we investigated if four hand gestures could be decoded using a single ECoG strip of four consecutive electrodes spaced 1 cm apart and compared the performance between a unipolar and a bipolar montage. For that we collected data of seven individuals with intractable epilepsy implanted with ECoG grids, covering the hand region of the sensorimotor cortex. Based on the implanted grids, we generated virtual ECoG strips and compared the decoding accuracy between (a) a single unipolar electrode (Unipolar Electrode), (b) a combination of four unipolar electrodes (Unipolar Strip), (c) a single bipolar pair (Bipolar Pair) and (d) a combination of six bipolar pairs (Bipolar Strip).Main results.We show that four hand gestures can be equally well decoded using 'Unipolar Strips' (mean 67.4 ± 11.7%), 'Bipolar Strips' (mean 66.6 ± 12.1%) and 'Bipolar Pairs' (mean 67.6 ± 9.4%), while 'Unipolar Electrodes' (61.6 ± 5.9%) performed significantly worse compared to 'Unipolar Strips' and 'Bipolar Pairs'.Significance.We conclude that a single bipolar pair is a potential candidate for minimally invasive motor-based BCIs and encourage the use of ECoG as a robust and reliable BCI platform for multi-class movement decoding.


Assuntos
Interfaces Cérebro-Computador , Eletrocorticografia , Eletrodos , Eletrodos Implantados , Eletroencefalografia , Gestos , Mãos , Humanos
8.
Lakartidningen ; 1182021 10 07.
Artigo em Sueco | MEDLINE | ID: mdl-34633059

RESUMO

In this paper, we report our experiences from the first 30 patients investigated with stereoelectroencephalography (SEEG) at Sahlgrenska University Hospital, Gothenburg, Sweden. Clinical, neurophysiological, and imaging data were reviewed. Twelve children and 18 adults with drug-resistant epilepsy underwent 33 SEEG procedures. 53% of the patients had normal brain MRI. In total, 347 SEEG electrodes were implanted (median 12 per patient). Twenty patients subsequently had resective surgery based on SEEG findings. Focal cortical dysplasia was found in all cases. In 45% of the patients, vicinity of eloquent cortex limited resections. Epilepsy surgery based on SEEG resulted in seizure freedom in 58% of the cases. Minor complications were seen in eight patients, all of which resolved without sequelae. No major complications were seen. SEEG is a safe and effective method to delineate cortical areas involved in seizure generation.


Assuntos
Eletroencefalografia , Epilepsia , Adulto , Criança , Eletrodos Implantados , Epilepsia/cirurgia , Humanos , Estudos Retrospectivos , Técnicas Estereotáxicas , Resultado do Tratamento
9.
Int Heart J ; 62(5): 1156-1159, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34544971

RESUMO

A rare complication about "Twiddler syndrome" is reported, and an interesting image about "double twist" is presented. A 78-year-old woman received a single-chamber implantable cardioverter defibrillator (ICD) for secondary prevention of ventricular arrhythmia. After she played mahjong (a traditional Chinese board game) overnight, her ICD lead sense amplitude decreased suddenly and did not recover. The intracardiac electrogram of ICD also found ventricular lead noise before this episode. Chest radiography revealed a twisted lead at the ICD pocket and a twisted and retracted ICD lead in the right atrium. An old ICD lead could not be straightened and removed, and a new ICD lead was implanted at the right ventricle. Anti-coagulation was used to prevent thrombosis for the old ICD lead.


Assuntos
Desfibriladores Implantáveis/efeitos adversos , Eletrodos Implantados/efeitos adversos , Prevenção Secundária/métodos , Taquicardia Ventricular/cirurgia , Idoso , Anticoagulantes/uso terapêutico , Remoção de Dispositivo/instrumentação , Eletrocardiografia/métodos , Falha de Equipamento , Feminino , Ventrículos do Coração/fisiopatologia , Ventrículos do Coração/cirurgia , Humanos , Trombose/prevenção & controle , Resultado do Tratamento
10.
J Neural Eng ; 18(5)2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34542029

RESUMO

Context.Long-term deep brain stimulation (DBS) studies in rodents are of crucial importance for research progress in this field. However, most stimulation devices require jackets or large head-mounted systems which severely affect mobility and general welfare influencing animals' behavior.Objective.To develop a preclinical neurostimulation implant system for long-term DBS research in small animal models.Approach.We propose a low-cost dual-channel DBS implant called software defined implantable platform (STELLA) with a printed circuit board size of Ø13 × 3.3 mm, weight of 0.6 g and current consumption of 7.6µA/3.1 V combined with an epoxy resin-based encapsulation method.Main results.STELLA delivers charge-balanced and configurable current pulses with widely used commercial electrodes. Whilein vitrostudies demonstrate at least 12 weeks of error-free stimulation using a CR1225 battery, our calculations predict a battery lifetime of up to 3 years using a CR2032. Exemplary application for DBS of the subthalamic nucleus in adult rats demonstrates that fully-implanted STELLA neurostimulators are very well-tolerated over 42 days without relevant stress after the early postoperative phase resulting in normal animal behavior. Encapsulation, external control and monitoring of function proved to be feasible. Stimulation with standard parameters elicited c-Fos expression by subthalamic neurons demonstrating biologically active function of STELLA.Significance.We developed a fully implantable, scalable and reliable DBS device that meets the urgent need for reverse translational research on DBS in freely moving rodent disease models including sensitive behavioral experiments. We thus add an important technology for animal research according to 'The Principle of Humane Experimental Technique'-replacement, reduction and refinement (3R). All hardware, software and additional materials are available under an open source license.


Assuntos
Estimulação Encefálica Profunda , Núcleo Subtalâmico , Animais , Eletrodos Implantados , Neuroestimuladores Implantáveis , Ratos , Roedores , Software
11.
Elife ; 102021 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-34505576

RESUMO

The strength of cortical connectivity to the striatum influences the balance between behavioral variability and stability. Learning to consistently produce a skilled action requires plasticity in corticostriatal connectivity associated with repeated training of the action. However, it remains unknown whether such corticostriatal plasticity occurs during training itself or 'offline' during time away from training, such as sleep. Here, we monitor the corticostriatal network throughout long-term skill learning in rats and find that non-rapid-eye-movement (NREM) sleep is a relevant period for corticostriatal plasticity. We first show that the offline activation of striatal NMDA receptors is required for skill learning. We then show that corticostriatal functional connectivity increases offline, coupled to emerging consistent skilled movements, and coupled cross-area neural dynamics. We then identify NREM sleep spindles as uniquely poised to mediate corticostriatal plasticity, through interactions with slow oscillations. Our results provide evidence that sleep shapes cross-area coupling required for skill learning.


Assuntos
Corpo Estriado/fisiologia , Aprendizagem/fisiologia , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Sono de Ondas Lentas/fisiologia , Animais , Eletrodos Implantados , Masculino , Plasticidade Neuronal/fisiologia , Desempenho Psicomotor/fisiologia , Ratos , Ratos Long-Evans , Silício , Fatores de Tempo
12.
Nat Commun ; 12(1): 5245, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475396

RESUMO

State-of-the-art silicon probes for electrical recording from neurons have thousands of recording sites. However, due to volume limitations there are typically many fewer wires carrying signals off the probe, which restricts the number of channels that can be recorded simultaneously. To overcome this fundamental constraint, we propose a method called electrode pooling that uses a single wire to serve many recording sites through a set of controllable switches. Here we present the framework behind this method and an experimental strategy to support it. We then demonstrate its feasibility by implementing electrode pooling on the Neuropixels 1.0 electrode array and characterizing its effect on signal and noise. Finally we use simulations to explore the conditions under which electrode pooling saves wires without compromising the content of the recordings. We make recommendations on the design of future devices to take advantage of this strategy.


Assuntos
Eletrodos Implantados , Eletrofisiologia/métodos , Espaço Extracelular/fisiologia , Silício/química , Potenciais de Ação , Animais , Encéfalo/fisiologia , Eletrofisiologia/instrumentação , Desenho de Equipamento , Camundongos , Rede Nervosa/fisiologia , Neurônios/fisiologia , Processamento de Sinais Assistido por Computador
13.
Clin Neurophysiol ; 132(11): 2766-2777, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34583119

RESUMO

OBJECTIVE: The aim of the present study was to investigate the optimal stimulation parameters for eliciting cortico-cortical evoked potentials (CCEPs) for mapping functional and epileptogenic networks. METHODS: We studied 13 patients with refractory epilepsy undergoing intracranial EEG monitoring. We systematically titrated the intensity of single-pulse electrical stimulation at multiple sites to assess the effect of increasing current on salient features of CCEPs such as N1 potential magnitude, signal to noise ratio, waveform similarity, and spatial distribution of responses. Responses at each incremental stimulation setting were compared to each other and to a final set of responses at the maximum intensity used in each patient (3.5-10 mA, median 6 mA). RESULTS: We found that with a biphasic 0.15 ms/phase pulse at least 2-4 mA is needed to differentiate between non-responsive and responsive sites, and that stimulation currents of 6-7 mA are needed to maximize amplitude and spatial distribution of N1 responses and stabilize waveform morphology. CONCLUSIONS: We determined a minimum stimulation threshold necessary for eliciting CCEPs, as well as a point at which the current-dependent relationship of several response metrics all saturate. SIGNIFICANCE: This titration study provides practical, immediate guidance on optimal stimulation parameters to study specific features of CCEPs, which have been increasingly used to map both functional and epileptic brain networks in humans.


Assuntos
Córtex Cerebral/fisiologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletrocorticografia/métodos , Eletrodos Implantados , Potenciais Evocados/fisiologia , Adulto , Mapeamento Encefálico/métodos , Epilepsia Resistente a Medicamentos/diagnóstico , Estimulação Elétrica/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
14.
Clin Neurophysiol ; 132(11): 2789-2797, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34592557

RESUMO

OBJECTIVE: This study aims to discriminate the dynamic synchronization states from the subthalamic local field potentials and investigate their correlations with the motor symptoms in Parkinson's Disease (PD). METHODS: The resting-state local field potentials of 10 patients with PD were recorded from the subthalamic nucleus. The dynamic neural states of multiple oscillations were discriminated and analyzed. The Spearman correlation was used to investigate the correlations between occurrence rate or duration of dynamic neural states and the severity of motor symptoms. RESULTS: The proportion of long low-beta and theta synchronized state was significantly correlated with the general motor symptom and tremor, respectively. The duration of combined low/high-beta state was significantly correlated with rigidity, and the duration of combined alpha/high-beta state was significantly correlated with bradykinesia. CONCLUSIONS: This study provides evidence that motor symptoms are associated with the neural states coded with multiple oscillations in PD. SIGNIFICANCE: This study may advance the understanding of the neurophysiological mechanisms of the motor symptoms and provide potential biomarkers for closed-loop deep brain stimulation in PD.


Assuntos
Ritmo beta/fisiologia , Transtornos Motores/fisiopatologia , Doença de Parkinson/fisiopatologia , Núcleo Subtalâmico/fisiopatologia , Ritmo Teta/fisiologia , Adulto , Estimulação Encefálica Profunda/métodos , Eletrodos Implantados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Motores/diagnóstico , Transtornos Motores/terapia , Doença de Parkinson/diagnóstico , Doença de Parkinson/terapia
15.
Biosensors (Basel) ; 11(9)2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34562938

RESUMO

Electrically controlled drug delivery of neurochemicals and biomolecules from conducting polymer microelectrode coatings hold great potentials in dissecting neural circuit or treating neurological disorders with high spatial and temporal resolution. The direct doping of a drug into a conducting polymer often results in low loading capacity, and the type of molecule that can be released is limited. Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with sulfonated silica nanoparticles (SNP) has been developed as a more versatile platform for drug delivery. In this work, we demonstrate that neurochemicals with different surface charge, e.g., glutamate (GLU), gamma-Aminobutyric acid (GABA), dopamine (DA), 6,7-Dinitroquinoxaline- 2,3-dione (DNQX) and bicuculline, can be, respectively, incorporated into the SNP and electrically triggered to release repeatedly. The drug loaded SNPs were incorporated in PEDOT via electrochemical deposition on platinum microelectrodes. After PEDOT/SNP(drug) coating, the charge storage capacity (CSC) increased 10-fold to 55 ± 3 mC/cm2, and the impedance at 1 kHz was also reduced approximately 6-fold. With the aid of a porous SNP, the loading capacity and number of releases of GLU was increased >4-fold and 66-fold, respectively, in comparison to the direct doping of PEDOT with GLU (PEDOT/GLU). The focal release of GLU and GABA from a PEDOT/SNP (drug) coated microelectrode were tested in cultured neurons using Ca imaging. The change in fluo-4 fluorescence intensity after electrically triggered GLU (+6.7 ± 2.9%) or GABA (-6.8 ± 1.6%) release indicated the successful modulation of neural activities by neurotransmitter release. In addition to activating neural activities, glutamate can also act on endothelial cells to stimulate nitric oxide (NO) release. A dual functional device with two adjacent sensing and releasing electrodes was constructed and we tested this mechanism in endothelial cell cultures. In endothelial cells, approximately 7.6 ± 0.6 nM NO was detected in the vicinity of the NO sensor within 6.2 ± 0.5 s of GLU release. The rise time of NO signal, T0-100, was 14.5 ± 2.2 s. In summary, our work has demonstrated (1) a platform that is capable of loading and releasing drugs with different charges; (2) proof of concept demonstrations of how focal release of drugs can be used as a pharmacological manipulation to study neural circuitry or NO's effect on endothelial cells.


Assuntos
Sistemas de Liberação de Medicamentos , Microeletrodos , Animais , Compostos Bicíclicos Heterocíclicos com Pontes , Materiais Revestidos Biocompatíveis , Impedância Elétrica , Eletrodos Implantados , Células Endoteliais , Nanopartículas , Neurônios , Platina , Polímeros
16.
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
17.
PLoS Biol ; 19(9): e3001393, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34529647

RESUMO

The receptive field of a neuron describes the regions of a stimulus space where the neuron is consistently active. Sparse spiking outside of the receptive field is often considered to be noise, rather than a reflection of information processing. Whether this characterization is accurate remains unclear. We therefore contrasted the sparse, temporally isolated spiking of hippocampal CA1 place cells to the consistent, temporally adjacent spiking seen within their spatial receptive fields ("place fields"). We found that isolated spikes, which occur during locomotion, are strongly phase coupled to hippocampal theta oscillations and transiently express coherent nonlocal spatial representations. Further, prefrontal cortical activity is coordinated with and can predict the occurrence of future isolated spiking events. Rather than local noise within the hippocampus, sparse, isolated place cell spiking reflects a coordinated cortical-hippocampal process consistent with the generation of nonlocal scenario representations during active navigation.


Assuntos
Hipocampo/fisiologia , Córtex Pré-Frontal/fisiologia , Navegação Espacial/fisiologia , Animais , Região CA1 Hipocampal/fisiologia , Eletrodos Implantados , Masculino , Ratos Long-Evans , Ritmo Teta
18.
Neuron ; 109(19): 3164-3177.e8, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34499856

RESUMO

Modern brain-machine interfaces can return function to people with paralysis, but current upper extremity brain-machine interfaces are unable to reproduce control of individuated finger movements. Here, for the first time, we present a real-time, high-speed, linear brain-machine interface in nonhuman primates that utilizes intracortical neural signals to bridge this gap. We created a non-prehensile task that systematically individuates two finger groups, the index finger and the middle-ring-small fingers combined. During online brain control, the ReFIT Kalman filter could predict individuated finger group movements with high performance. Next, training ridge regression decoders with individual movements was sufficient to predict untrained combined movements and vice versa. Finally, we compared the postural and movement tuning of finger-related cortical activity to find that individual cortical units simultaneously encode multiple behavioral dimensions. Our results suggest that linear decoders may be sufficient for brain-machine interfaces to execute high-dimensional tasks with the performance levels required for naturalistic neural prostheses.


Assuntos
Interfaces Cérebro-Computador , Dedos/fisiologia , Movimento/fisiologia , Próteses Neurais , Algoritmos , Animais , Fenômenos Biomecânicos , Eletrodos Implantados , Dedos/inervação , Previsões , Modelos Lineares , Macaca mulatta , Masculino , Microeletrodos , Córtex Motor/fisiologia , Postura/fisiologia , Desenho de Prótese , Desempenho Psicomotor
19.
Am J Cardiol ; 158: 53-58, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34503824

RESUMO

Rhythm-symptom correlation in pediatric patients with syncope/palpitations or at risk cohorts can be difficult, but important given potential associations with treatable or malignant arrhythmia. We sought to evaluate the use, efficacy and outcomes of implantable loop recorders (ILR) in pediatrics. We conducted a retrospective study of pediatric patients (<21 years) with implanted ILR. Patient/historical characteristics and ILR indication were obtained. Outcomes including symptom documentation, arrhythmia detection and ILR based changes in medical care were identified. Comparison of outcomes were performed based on implant indication. Additional sub-analyses were performed in syncope-indication patients comparing those with and without changes in clinical management. A total of 116 patients with ILR implant were identified (79 syncope/37 other). Symptoms were documented 58% of patients (syncope 68% vs nonsyncope 35%; p = 0.002). A total of 37% of patients had a documented clinically significant arrhythmia and 25% of patients had a resultant change in clinical management independent of implant indication. Arrhythmia type was dependent on implant indication with nonsyncope patients having more ventricular arrhythmias. Pacemaker/defibrillator implantation and mediation management were the majority of the clinical changes. In conclusion, IRL utilization in selected pediatric populations is associated with high efficacy and supports clinical management. ILR efficacy is similar regardless of indication although patients with nonsyncope indications had a higher frequency of ventricular arrhythmias as opposed to asystole and heart block in syncope indications. The majority of arrhythmic findings occurred in the first 12 months, and new technology that would allow for less invasive monitoring for 6 to 12 months may be of value.


Assuntos
Arritmias Cardíacas/complicações , Arritmias Cardíacas/diagnóstico , Eletrocardiografia Ambulatorial/instrumentação , Eletrodos Implantados , Síncope/etiologia , Adolescente , Fatores Etários , Arritmias Cardíacas/terapia , Criança , Humanos , Seleção de Pacientes , Estudos Retrospectivos , Síncope/diagnóstico , Síncope/prevenção & controle , Resultado do Tratamento , Adulto Jovem
20.
Nat Commun ; 12(1): 5289, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489419

RESUMO

Microglia are brain-resident immune cells with a repertoire of functions in the brain. However, the extent of their interactions with the vasculature and potential regulation of vascular physiology has been insufficiently explored. Here, we document interactions between ramified CX3CR1 + myeloid cell somata and brain capillaries. We confirm that these cells are bona fide microglia by molecular, morphological and ultrastructural approaches. Then, we give a detailed spatio-temporal characterization of these capillary-associated microglia (CAMs) comparing them with parenchymal microglia (PCMs) in their morphological activities including during microglial depletion and repopulation. Molecularly, we identify P2RY12 receptors as a regulator of CAM interactions under the control of released purines from pannexin 1 (PANX1) channels. Furthermore, microglial elimination triggered capillary dilation, blood flow increase, and impaired vasodilation that were recapitulated in P2RY12-/- and PANX1-/- mice suggesting purines released through PANX1 channels play important roles in activating microglial P2RY12 receptors to regulate neurovascular structure and function.


Assuntos
Encéfalo/irrigação sanguínea , Conexinas/genética , Microglia/metabolismo , Células Mieloides/metabolismo , Proteínas do Tecido Nervoso/genética , Receptores Purinérgicos P2Y12/genética , Animais , Encéfalo/citologia , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/metabolismo , Contagem de Células , Circulação Cerebrovascular/fisiologia , Conexinas/deficiência , Eletrodos Implantados , Feminino , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos , Camundongos Knockout , Microglia/citologia , Células Mieloides/citologia , Proteínas do Tecido Nervoso/deficiência , Neuroimagem/instrumentação , Neuroimagem/métodos , Receptores Purinérgicos P2Y12/deficiência , Receptores Purinérgicos P2Y12/metabolismo , Vasodilatação/fisiologia
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