Letteratura scientifica selezionata sul tema "Stimulation corticale directe"
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Articoli di riviste sul tema "Stimulation corticale directe"
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Ahmed, Zaghloul, e Andrzej Wieraszko. "Trans-spinal direct current enhances corticospinal output and stimulation-evoked release of glutamate analog, D-2,3-3H-aspartic acid". Journal of Applied Physiology 112, n. 9 (1 maggio 2012): 1576–92. http://dx.doi.org/10.1152/japplphysiol.00967.2011.
Testo completoAbstract (sommario):
Trans-spinal direct current (tsDC) stimulation is a modulator of spinal excitability and can influence cortically elicited muscle contraction in a polarity-dependent fashion. When combined with low-frequency repetitive cortical stimulation, cathodal tsDC [tsDC(−)] produces a long-term facilitation of cortically elicited muscle actions. We investigated the ability of this combined stimulation paradigm to facilitate cortically elicited muscle actions in spinal cord-injured and noninjured animals. The effect of tsDC—applied alone or in combination with repetitive spinal stimulation (rSS) on the release of the glutamate analog, D-2,3-3H-aspartate (D-Asp), from spinal cord preparations in vitro—was also tested. In noninjured animals, tsDC (−2 mA) reproducibly potentiated cortically elicited contractions of contralateral and ipsilateral muscles tested at various levels of baseline muscle contraction forces. Cortically elicited muscle responses in animals with contusive and hemisectioned spinal cord injuries (SCIs) were similarly potentiated. The combined paradigm of stimulation caused long-lasting potentiation of cortically elicited bilateral muscle contraction in injured and noninjured animals. Additional analysis suggests that at higher baseline forces, tsDC(−) application does not increase the rising slope of the muscle contraction but causes repeated firing of the same motor units. Both cathodal and anodal stimulations induced a significant increase of D-Asp release in vitro. The effect of the combined paradigm of stimulation (tsDC and rSS) on the concentration of extracellular D-Asp was polarity dependent. These results indicate that tsDC can powerfully modulate the responsiveness of spinal cord neurons. The results obtained from the in vitro preparation suggest that the changes in neuronal excitability were correlated with an increased concentration of extracellular glutamate. The combined paradigm of stimulation, used in our experiments, could be noninvasively applied to restore motor control in humans with SCI.
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Foster, Brett L., e Josef Parvizi. "Direct cortical stimulation of human posteromedial cortex". Neurology 88, n. 7 (18 gennaio 2017): 685–91. http://dx.doi.org/10.1212/wnl.0000000000003607.
Testo completoAbstract (sommario):
Background:The posteromedial cortex (PMC) is a collective term for an anatomically heterogeneous area of the brain constituting a core node of the human default mode network (DMN), which is engaged during internally focused subjective cognition such as autobiographical memory.Methods:We explored the effects of causal perturbations of PMC with direct electric brain stimulation (EBS) during presurgical epilepsy monitoring with intracranial EEG electrodes.Results:Data were collected from 885 stimulations in 25 patients implanted with intracranial electrodes across the PMC. While EBS of regions immediately dorsal or ventral to the PMC reliably produced somatomotor or visual effects, respectively, we found no observable behavioral or subjectively reported effects when sites within the boundaries of PMC were electrically perturbed. In each patient, null effects of PMC stimulation were observed for sites in which intracranial recordings had clearly demonstrated electrophysiologic responses during autobiographical recall.Conclusions:Direct electric modulation of the human PMC produced null effects when standard functional mapping methods were used. More sophisticated stimulation paradigms (e.g., EBS during experimental cognitive tests) will be required for testing the causal contribution of PMC to human cognition and subjective experience. Nonetheless, our findings suggest that some extant theories of PMC and DMN contribution to human awareness and subjective conscious states require cautious re-examination.
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Lee, Hongju, Juyeon Lee, Dahee Jung, Harim Oh, Hwakyoung Shin e Byungtae Choi. "Neuroprotection of Transcranial Cortical and Peripheral Somatosensory Electrical Stimulation by Modulating a Common Neuronal Death Pathway in Mice with Ischemic Stroke". International Journal of Molecular Sciences 25, n. 14 (9 luglio 2024): 7546. http://dx.doi.org/10.3390/ijms25147546.
Testo completoAbstract (sommario):
Therapeutic electrical stimulation, such as transcranial cortical stimulation and peripheral somatosensory stimulation, is used to improve motor function in patients with stroke. We hypothesized that these stimulations exert neuroprotective effects during the subacute phase of ischemic stroke by regulating novel common signaling pathways. Male C57BL/6J mouse models of ischemic stroke were treated with high-definition (HD)-transcranial alternating current stimulation (tACS; 20 Hz, 89.1 A/mm2), HD-transcranial direct current stimulation (tDCS; intensity, 55 A/mm2; charge density, 66,000 C/m2), or electroacupuncture (EA, 2 Hz, 1 mA) in the early stages of stroke. The therapeutic effects were assessed using behavioral motor function tests. The underlying mechanisms were determined using transcriptomic and other biomedical analyses. All therapeutic electrical tools alleviated the motor dysfunction caused by ischemic stroke insults. We focused on electrically stimulating common genes involved in apoptosis and cell death using transcriptome analysis and chose 11 of the most potent targets (Trem2, S100a9, Lgals3, Tlr4, Myd88, NF-kB, STAT1, IL-6, IL-1β, TNF-α, and Iba1). Subsequent investigations revealed that electrical stimulation modulated inflammatory cytokines, including IL-1β and TNF-α, by regulating STAT1 and NF-kB activation, especially in amoeboid microglia; moreover, electrical stimulation enhanced neuronal survival by activating neurotrophic factors, including BDNF and FGF9. Therapeutic electrical stimulation applied to the transcranial cortical- or periphery-nerve level to promote functional recovery may improve neuroprotection by modulating a common neuronal death pathway and upregulating neurotrophic factors. Therefore, combining transcranial cortical and peripheral somatosensory stimulation may exert a synergistic neuroprotective effect, further enhancing the beneficial effects on motor deficits in patients with ischemic stroke.
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Adeel, Muhammad, Chun-Ching Chen, Bor-Shing Lin, Hung-Chou Chen, Jian-Chiun Liou, Yu-Ting Li e Chih-Wei Peng. "Safety of Special Waveform of Transcranial Electrical Stimulation (TES): In Vivo Assessment". International Journal of Molecular Sciences 23, n. 12 (20 giugno 2022): 6850. http://dx.doi.org/10.3390/ijms23126850.
Testo completoAbstract (sommario):
Intermittent theta burst (iTBS) powered by direct current stimulation (DCS) can safely be applied transcranially to induce neuroplasticity in the human and animal brain cortex. tDCS-iTBS is a special waveform that is used by very few studies, and its safety needs to be confirmed. Therefore, we aimed to evaluate the safety of tDCS-iTBS in an animal model after brain stimulations for 1 h and 4 weeks. Thirty-one Sprague Dawley rats were divided into two groups: (1) short-term stimulation for 1 h/session (sham, low, and high) and (2) long-term for 30 min, 3 sessions/week for 4 weeks (sham and high). The anodal stimulation applied over the primary motor cortex ranged from 2.5 to 4.5 mA/cm2. The brain biomarkers and scalp tissues were assessed using ELISA and histological analysis (H&E staining) after stimulations. The caspase-3 activity, cortical myelin basic protein (MBP) expression, and cortical interleukin (IL-6) levels increased slightly in both groups compared to sham. The serum MBP, cortical neuron-specific enolase (NSE), and serum IL-6 slightly changed from sham after stimulations. There was no obvious edema or cell necrosis seen in cortical histology after the intervention. The short- and long-term stimulations did not induce significant adverse effects on brain and scalp tissues upon assessing biomarkers and conducting histological analysis.
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Yaksh, Tony L., Jia-Yi Wang, V. L. W. Go e Gail J. Harty. "Cortical Vasodilatation Produced by Vasoactive Intestinal Polypeptide (VIP) and by Physiological Stimuli in the Cat". Journal of Cerebral Blood Flow & Metabolism 7, n. 3 (giugno 1987): 315–26. http://dx.doi.org/10.1038/jcbfm.1987.69.
Testo completoAbstract (sommario):
In chloralose-urethanized cats, vasoactive intestinal peptide (VIP), applied by superfusion in steady-state concentration (10−10–10−6 M) onto cortical vessels in situ resulted in a rapid concentration-dependent vasodilatation in vessels that were mildly constricted by prostaglandin F2α (PGF2α) (5 × 10−5 M) or hypocarbia (PaCO2 = 26). The maximum dilatation produced by VIP (10−6 M) was about 60% over baseline in pial arteries and 40% in pial veins. Blockade of local neuronal activity with tetrodotoxin (TTX) (10−5 M) had no effect on the VIP-evoked dilation of pial vessels. Activation of the cortex by either direct electrical stimulation or indirectly by stimulation of the mesencephalic reticular formation (MRF) resulted in a rapid dilatation of pial arterioles and venules. The vasodilatory effects of VIP and of cortical activation via direct cortical stimulation were not blocked by phentolamine (10−4 M), propranolol (10−4 M), atropine (10−4 M), or naloxone (10−4 M), indicating that the stimulated vasodilatation was not mediated by adrenergic, cholinergic, or opiate receptors. The dilatory effects of MRF, but not direct cortical stimulation, were not blocked by TTX. VIP antiserum (1:25) preincubated in cortical cups had no effect on resting vessel diameter, but resulted in a significant, though subtotal, reduction in the vasodilatation elicited by direct cortical and MRF stimulation. Normal rabbit sera or VIP antiserum preincubated with saturating amounts of VIP were ineffective. In similar experiments, pial arteriolar and venular dilation evoked by hypercarbia was not attenuated by cortically applied VIP antisera. These observations suggest that pial dilation evoked by local increases in neuronal activity may be mediated in part by the local release of VIP from intrinsic neurons. Such a substrate would define a close obligatory coupling between local neuronal activation and local perfusion, such that nutritive flow could be enhanced prior to the onset of any metabolic deficit.
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Huang, Yuhao (Danny), Sydney Cash, Corey Keller e Angelique Paulk. "243 Intracranial Theta-burst Stimulation Modulates Cortical Excitability in a Dose and Location-dependent Fashion". Neurosurgery 70, Supplement_1 (aprile 2024): 67. http://dx.doi.org/10.1227/neu.0000000000002809_243.
Testo completoAbstract (sommario):
INTRODUCTION: Direct electrical stimulation is a powerful therapeutic approach to treating a wide range of brain disorders. In particular, theta-burst stimulation (TBS) which delivers electrical pulses in rhythmic bursts of 3-8 Hz to mimic endogenous brain rhythms, has been increasingly used to improve cognitive processes and relieve symptoms of depression. However, how TBS alters underlying neural activity is poorly understood. METHODS: In nine neurosurgical epilepsy subjects undergoing intracranial monitoring, we applied direct cortical TBS at varying stimulation amplitudes and locations (prefrontal, temporal, parietal). We obtained single-pulse corticocortical evoked potentials (CCEPs) prior to stimulation to map functional connectivity. Intracranial EEG (iEEG) was recorded from non-stimulated electrodes before, during and after TBS. RESULTS: We found that TBS evoked consistent responses after each burst. These responses were observed in regions with high amplitude CCEPs and resting spontaneous delta (1-4 Hz) phase-locking to the stimulation site, consistent with our hypothesis that the underlying functional brain architecture guides information flow after stimulation. Furthermore, we observed changes in cortical excitability over time as measured by changes in amplitude of the TBS evoked responses both within stimulation burst trains and across burst trains. The degree of change in cortical excitability was modulated by anatomical location, proximity of the stimulating electrode to white matter, and current amplitude. CONCLUSIONS: These results indicate that direct cortical TBS produces neural effects that can be measured over time and correlate with baseline biophysical parameters. Thus, personalizing stimulation parameters might be critical to predictably maximize our ability to alter disease-relevant brain networks.
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Moliadze, Vera, Georg Fritzsche e Andrea Antal. "Comparing the Efficacy of Excitatory Transcranial Stimulation Methods Measuring Motor Evoked Potentials". Neural Plasticity 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/837141.
Testo completoAbstract (sommario):
The common aim of transcranial stimulation methods is the induction or alterations of cortical excitability in a controlled way. Significant effects of each individual stimulation method have been published; however, conclusive direct comparisons of many of these methods are rare. The aim of the present study was to compare the efficacy of three widely applied stimulation methods inducing excitability enhancement in the motor cortex: 1 mA anodal transcranial direct current stimulation (atDCS), intermittent theta burst stimulation (iTBS), and 1 mA transcranial random noise stimulation (tRNS) within one subject group. The effect of each stimulation condition was quantified by evaluating motor-evoked-potential amplitudes (MEPs) in a fixed time sequence after stimulation. The analyses confirmed a significant enhancement of the M1 excitability caused by all three types of active stimulations compared to sham stimulation. There was no significant difference between the types of active stimulations, although the time course of the excitatory effects slightly differed. Among the stimulation methods, tRNS resulted in the strongest and atDCS significantly longest MEP increase compared to sham. Different time courses of the applied stimulation methods suggest different underlying mechanisms of action. Better understanding may be useful for better targeting of different transcranial stimulation techniques.
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Ahmed, Zaghloul. "Trans-spinal direct current stimulation modulates motor cortex-induced muscle contraction in mice". Journal of Applied Physiology 110, n. 5 (maggio 2011): 1414–24. http://dx.doi.org/10.1152/japplphysiol.01390.2010.
Testo completoAbstract (sommario):
The present study investigated the effect of trans-spinal direct current (tsDC) on the firing rate, pattern, and amplitude of spontaneous activity of the tibial nerve and on the magnitude of cortically elicited triceps surae (TS) muscle contractions. The effect of combined tsDC and repetitive cortical electrical stimulation (rCES) on the amplitude of cortically elicited TS twitches was also investigated. Stimulation was applied by two disk electrodes (0.79 cm2): one was located subcutaneously over the vertebral column (T10–L1) and was used to deliver anodal DC (a-tsDC) or cathodal DC (c-tsDC) (density range: ± 0.64 to ± 38.2 A/m2), whereas the other was located subcutaneously on the lateral aspect of the abdomen and served as a reference. While the application of a-tsDC significantly increased the spike frequency and amplitude of spontaneous discharges compared with c-tsDC, c-tsDC made the spontaneous discharges more rhythmic. Cortically elicited TS twitches were depressed during a-tsDC and potentiated after termination. Conversely, cortically elicited TS twitches were enhanced during c-tsDC and depressed after termination. While combined a-tsDC and rCES produced similar effects as a-tsDC alone, combined c-tsDC and rCES showed the greatest increase in cortically elicited TS twitches. tsDC appears to be a powerful neurostimulation tool that can differentially modulate spinal cord excitability and corticospinal transmission.
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Ip, Emily Y., Elisa Roncati Zanier, Amy H. Moore, Stefan M. Lee e David A. Hovda. "Metabolic, Neurochemical, and Histologic Responses to Vibrissa Motor Cortex Stimulation after Traumatic Brain Injury". Journal of Cerebral Blood Flow & Metabolism 23, n. 8 (agosto 2003): 900–910. http://dx.doi.org/10.1097/01.wcb.0000076702.71231.f2.
Testo completoAbstract (sommario):
During the prolonged metabolic depression after traumatic brain injury (TBI), neurons are less able to respond metabolically to peripheral stimulation. Because this decreased responsiveness has been attributed to circuit dysfunction, the present study examined the metabolic, neurochemical, and histologic responses to direct cortical stimulation after lateral fluid percussion injury (LFPI). This study addressed three specific hypotheses: that neurons, if activated after LFPI, will increase their utilization of glucose even during a period of posttraumatic metabolic depression; that this secondary activation results in an increase in the production of lactate and a depletion of extracellular glucose; and that because cells are known to be in a state of energy crisis after traumatic brain injury, additional energy demands resulting from activation can result in their death. The results indicate that stimulating to levels eliciting a vibrissa twitch resulted in an increase in the cerebral metabolic rate for glucose (CMRglc; μmol·100 g−1·min−1) of 34% to 61% in the sham-operated, 1-hour LFPI, and 7-day LFPI groups. However, in the 1-day LFPI group, stimulation induced a 161% increase in CMRglc and a 35% decrease in metabolic activation volume. Extracellular lactate concentrations during stimulation significantly increased from 23% in the sham-injured group to 55% to 63% in the 1-day and 7-day LFPI groups. Extracellular glucose concentrations during stimulation remained unchanged in the sham-injured and 7-day LFPI groups, but decreased 17% in the 1-day LFPI group. The extent of cortical degeneration around the stimulating electrode in the 1-day LFPI group nearly doubled when compared with controls. These results indicate that at 1 day after LFPI, the cortex can respond to stimulation with an increase in anaerobic glycolysis; however, this metabolic response to levels eliciting a vibrissa response via direct cortical stimulation appears to constitute a secondary injury in the TBI brain.
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Qi, Xiaofei, Kexin Lyu, Long Meng, Cuixian Li, Hongzheng Zhang, Lili Niu, Zhengrong Lin, Hairong Zheng e Jie Tang. "Low-Intensity Ultrasound Causes Direct Excitation of Auditory Cortical Neurons". Neural Plasticity 2021 (4 aprile 2021): 1–10. http://dx.doi.org/10.1155/2021/8855055.
Testo completoAbstract (sommario):
Cochlear implantation is the first-line treatment for severe and profound hearing loss in children and adults. However, deaf patients with cochlear malformations or with cochlear nerve deficiencies are ineligible for cochlear implants. Meanwhile, the limited spatial selectivity and high risk of invasive craniotomy restrict the wide application of auditory brainstem implants. A noninvasive alternative strategy for safe and effective neuronal stimulation is urgently needed to address this issue. Because of its advantage in neural modulation over electrical stimulation, low-intensity ultrasound (US) is considered a safe modality for eliciting neural activity in the central auditory system. Although the neural modulation ability of low-intensity US has been demonstrated in the human primary somatosensory cortex and primary visual cortex, whether low-intensity US can directly activate auditory cortical neurons is still a topic of debate. To clarify the direct effects on auditory neurons, in the present study, we employed low-intensity US to stimulate auditory cortical neurons in vitro. Our data show that both low-frequency (0.8 MHz) and high-frequency (>27 MHz) US stimulation can elicit the inward current and action potentials in cultured neurons. c-Fos staining results indicate that low-intensity US is efficient for stimulating most neurons. Our study suggests that low-intensity US can excite auditory cortical neurons directly, implying that US-induced neural modulation can be a potential approach for activating the auditory cortex of deaf patients.
Tesi sul tema "Stimulation corticale directe"
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Hayatou, Zineb. "Appropriation d'une prothèse de membre supérieur chez la sourisEmbodiment of a forelimb prosthesis in the mouse model". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL045.
Testo completoAbstract (sommario):
Les recherches sur l'appropriation corporelle sont essentielles pour le développement des prothèses. En effet, l'incapacité à s’approprier une prothèse entraîne inconfort et douleurs fantômes chez de nombreux patients. Pour améliorer l'acceptation et l'utilisation des prothèses, il est donc crucial de comprendre et de pouvoir manipuler ce sens d’appropriation. Le modèle souris présente de nombreux avantages pour ces recherches grâce à ses comportements riches de membres supérieurs ainsi qu’aux technologies optogénétiques disponibles d’abord chez ce modèle. Ces techniques permettent une exploration précise du rôle du retour tactile dans l’appropriation des prothèses, et constituent une approche novatrice pour étudier ce phénomène. Dans le cadre de cette thèse j’ai participé à la construction d’un prototype d’une prothèse motorisée à l’échelle de la souris qui peut être contrôlé par l’activité neuronale enregistrée à l’aide d’électrodes chroniques implantées dans le cortex moteur des animaux. L'étude de l’appropriation est particulièrement importante dans le cadre du développement de notre modèle de neuroprothèse, pour comprendre l’interaction de différents éléments sensoriels ou moteurs sur l’intégration d’un membre artificiel. Pour étudier cette question ma thèse s’est focalisée sur l’utilisation de méthodes comportementales exploitant des illusions perceptives pour manipuler l’appropriation de membres. Ainsi, dans l'illusion de la main en caoutchouc, grâce à des stimulations visuelles et tactiles synchrones, les participants s’approprient comme faisant partie de leur corps une fausse main placée devant eux, tandis que leur vraie main reste cachée. Nous avons adapté cette illusion au modèle souris pour explorer le rôle du retour tactile dans l’appropriation des prothèses. Nous avons exposé des souris à ce paradigme, en les plaçant devant une prothèse ressemblant à leur patte, pendant que cette dernière est cachée. Après 2 minutes de stimulations, nous menaçons la patte et observons les réactions des animaux à cette menace avec une analyse automatisée de différents points d’intérêt de la face de l’animal. Les animaux montrent des signes d’appropriation envers la prothèse, démontrant que ce sens peut être étudié à ce niveau chez la souris. Dans le contexte du développement de neuroprothèses, il est nécessaire de pouvoir fournir un retour tactile artificiel aux patients quand le membre en périphérie a été perdu. C’est dans cette optique que nous avons exploré la possibilité d’induire cette illusion via des stimulations corticales des régions sensorielles de la patte par optogénétique. Nous avons d’abord mené une étude d’observation des dynamiques corticales générées par des stimulations de la patte en périphérie en utilisant de l’imagerie calcique. Cela nous a permis d’adapter nos stimulations optogénétiques pour mimer l’entrée sensorielle en périphérie. Nous avons ensuite reproduit notre premier protocole de l’illusion classique en replaçant les stimulations tactiles de la patte par des stimulations directes corticales. Les résultats préliminaires de ces expériences montrent un effet similaire à ce qui a été observé auparavant avec l’illusion classique, montrant la possibilité d’induire l’appropriation d’une prothèse à travers un retour tactile cortical. À terme, ces travaux ont permis de développer une plateforme de recherche chez le modèle souris pour le développement de neuroprothèses et permettront de développer de meilleures stratégies de retour sensoriel, pour un meilleur contrôle et une meilleure appropriation des prothèses chez des patientsResearch on bodily embodiment is necessary for the development of prostheses. Indeed, the inability to embody a prosthesis is a source of discomfort and is accompanied by phantom pain in the residual limbs of many amputees. The mouse model offers many advantages for this type of research due to its rich upper limb behaviours and the availability of optogenetic technologies in this model. These techniques allow for precise exploration of the role of tactile feedback in prosthesis embodiment and represent an innovative approach to studying this phenomenon. As part of this thesis, I contributed to the construction of a motorized prosthesis prototype at the mouse scale, controllable by neuronal activity recorded using chronic electrodes implanted in the animals' motor cortex. The study of embodiment is particularly important in the context of developing a neuroprosthesis model to understand the interaction of various sensory or motor elements on the integration of an artificial limb. To investigate this question, my thesis focused on using behavioural methods, exploiting perceptual illusions to manipulate limb embodiment. For instance, in the rubber hand illusion, synchronous visual and tactile stimulations cause participants to perceive a fake hand placed in front of them as part of their body, while their real hand remains hidden. We adapted this illusion in the mouse model to explore the role of tactile feedback in prosthesis embodiment. We exposed mice to this paradigm by placing them in front of a prosthesis resembling their paw while hiding their actual paw. After 2 minutes of stimulations, we threatened the paw and observed the animals' reactions to this threat using an automated analysis of various points of interest on the animal's face. The animals showed signs of embodiment towards the prosthesis, demonstrating that this sense can be studied at this level in mice. In the context of neuroprosthesis development, it is necessary to provide artificial tactile feedback to patients when the peripheral limb is lost. With this goal in mind, we explored the possibility of inducing this illusion through cortical stimulations of the sensory regions of the paw using optogenetics. We first conducted an observational study of the cortical dynamics generated by peripheral paw stimulations using calcium imaging. This allowed us to adapt our optogenetic stimulations to mimic peripheral sensory input. We then replicated our initial classical illusion protocol by replacing the tactile stimulations of the paw with direct cortical stimulations. The preliminary results of these experiments showed a similar effect to what was previously observed with the classical illusion, indicating the possibility of inducing prosthesis embodiment through cortical tactile feedback. Ultimately, this work led to the creation of a research platform using the mouse model for neuroprosthetic development which could help in providing better sensory feedback strategies for improved control and embodiment of prostheses in patients
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Lacuey, Lecumberri Nuria. "Human autonomic and respiratory responses to direct cortical electrical stimulation". Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666840.
Testo completoAbstract (sommario):
Los pacientes con epilepsia son bien conocidos por tener un mayor riesgo de muerte súbita inesperada. El riesgo de muerte súbita inesperada en pacientes con epilepsia (SUDEP) varía de 0,35 a 2,3 por cada 1000 personas por año en las poblaciones de base comunitaria, a 6,3 a 9,3 en los candidatos a cirugía para la epilepsia. Los mecanismos agónicos precisos que desencadenan SUDEP son desconocidos, aunque la evidencia reciente del estudio de unidades de monitoreo de Epilepsia (MORTEMUS) apunta al colapso combinado respiratorio y cardiovascular que conduce al fatal evento.
Los signos adversos del sistema nervioso autónomo son prominentes durante las convulsiones. Arritmias cardíacas (bradicardia, asistolia, taquiarritmias) en aproximadamente el 72% de los pacientes con epilepsia, hipotensión post ictal, sensibilidad barorrefleja alterada (que puede comprometer el flujo sanguíneo cerebral), incremento del tono simpático, expresado como aumento de la sudoración y disminución de la variabilidad inter-ictal del ritmo cardíaco nocturno (HRV) son comunes. La alteración severa de la respiración se ve típicamente en las convulsiones clónicas tónicas generalizadas (GTCS). Las características del electroencefalograma (EEG), incluida la supresión generalizada post-ictal en el EEG (PGES), sugieren un alto riesgo de SUDEP, se correlacionan fuertemente con un aumento de la sudoración y una disminución de la HRV y pueden ir acompañadas de hipotensión profunda. Los mecanismos neuronales subyacentes a estos patrones necesitan ser definidos.
La epilepsia es un trastorno cortical prototípico, donde la mayoría de los síntomas se producen por la activación o inhibición de regiones específicas en la corteza. Las descargas epileptiformes que involucran un área específica en el cerebro pueden inducir síntomas relacionados con la funcionalidad de ese área. De manera similar, la estimulación eléctrica del cerebro se puede usar para mapear funciones cerebrales.
Aunque varios estudios que usan estimulación eléctrica cerebral han sugerido el posible papel de estructuras corticales en la respiración y el control autonómico, los informes de algunos investigadores han indicado hallazgos mixtos, de tal manera que no hay consenso sobre las áreas precisas de la corteza involucrada.
Nuestro objetivo fue identificar los sitios corticales con funciones en el control respiratorio y/o autonómico y correlacionar la activación inducida por las crisis epilepticas o la inhibición de estas estructuras, con particulares patrones autonómicos y respiratorios peri-ictales reconocidos como posibles índices de riesgo de muerte. Este estudio describe el papel de varias estructuras límbicas/paralímbicas en la respiración y el control de la presión arterial humana, y los mecanismos patogénicos de la respiración y las respuestas autonómicas durante las crisis epilépticas, proporcionando información sobre los mecanismos que pueden desencadenan la muerte súbita inesperada en los pacientes con epilepsia (SUDEP).Patients with epilepsy are well known to be at increased risk of sudden unexpected death. The risk of Sudden Unexpected Death in Epilepsy Patients (SUDEP) ranges from 0.35 to 2.3 per 1000 people per year in community-based populations, to 6.3 to 9.3 in epilepsy surgery candidates. SUDEP’s precise agonal mechanisms are unknown, although recent evidence from the Mortality in Epilepsy Monitoring Units Study (MORTEMUS) points to combined respiratory and cardiovascular collapse driving the fatal event. Adverse autonomic nervous system signs are prominent during seizures. Cardiac arrhythmias (bradycardia, asystole, tachyarrhythmias) in approximately 72% of epilepsy patients, post-ictal hypotension, impaired baroreflex sensitivity (potentially compromising cerebral blood flow), enhanced sympathetic outflow, expressed as increased sweating and decreased inter-ictal nocturnal heart rate variability (HRV) are common. Severe alteration of breathing is typically seen in generalized tonic clonic seizures (GTCS). Electroencephalogram (EEG) characteristics, including post-ictal generalized EEG suppression (PGES), are suggestive of high SUDEP-risk, strongly correlate with increased sweating and decreased HRV, and may be accompanied by profound hypotension. Neural mechanisms underlying these patterns need to be defined. Epilepsy is a prototypic cortical disorder, where most of the symptoms are produced by the activation or inhibition of specific regions in the cortex. Epileptiform discharges involving a specific area in the brain may induce symptoms related with that area’s functionality. In a similar manner, electrical brain stimulation can be used to map brain functions. Although several studies using brain electrical stimulation have suggested the possible role of cortical structures in respiration and autonomic control, reports from some investigators have indicated mixed findings, such that there is no consensus on the precise areas of cortex concerned. We aimed to identify cortical sites with roles in respiratory and/or autonomic control and to correlate seizure induced activation or inhibition of these structures to particular peri-ictal autonomic and breathing patterns recognized as potential indices of risk for death. This study describes the role of several limbic/paralimbic structures in respiration and human blood pressure control, and pathomechanisms of breathing and autonomic responses during epileptic seizures, providing insights into mechanisms of failure in SUDEP.
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Austin, Vivienne Catherine Marie. "fMRI investigation of a model of direct cortical stimulation in rodent brain". Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275373.
Testo completo
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Mottolese, Carmine. "Étude per-opératoire par stimulation électrique directe des représentation sensorimotrices corticales et cérébelleuses chez l'homme". Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10303.
Testo completoAbstract (sommario):
Durant les dernières décennies, le système moteur a été largement étudié. Pourtant, bien des zones d'incertitudes persistent concernant d'une part la nature des circuits neuronaux de haut niveau impliqués dans l'émergence des sentiments d'intention ou de conscience motrice et d'autre part l'organisation des structures cérébrales de bas-niveau impliquées dans l'expression de ces sentiments. Il a été suggéré que le cortex pariétal et l'aire motrice supplémentaire pourraient jouer un rôle dans la génération des intentions motrices, alors que le cortex prémoteur pourrait plutôt sous-tendre la conscience du geste. Cela étant, les processus exacts implémentés dans chacune de ces régions, la façon dont elles interagissent fonctionnellement et la nature des signaux qu'elles échangent avec les structures sensorimotrices considérées de bas-niveau demeurent méconnus. Il est établi que ces structures bas-niveau, dont le cortex moteur primaire et le cervelet, contiennent des cartes sensorimotrices organisées de manière topographique. Cependant, l'organisation fine de cette topographie et la nature des interactions entre les différentes cartes restent à définir. Dans ce travail de thèse, j'ai utilisé la stimulation électrique directe chez des patients opérés de tumeurs et malformations cérébrales pour explorer la manière dont les multiples représentations motrices sont organisées et pour identifier les régions responsables de l'émergence des sentiments d'intention et de conscience motrice. J'ai alors pu montrer, en particulier, l'existence de cartes motrices multiples au sein des cortex moteur primaire et cérébelleux. Par ailleurs, j'ai pu identifier le rôle critique du cortex pariétal pour l'émergence du sentiment d'intention motrice et -sur la base de processus prédictifs- de la conscience d'agir. Par rapport à ce point, j'ai aussi pu mettre en évidence que le cortex prémoteur était impliqué, à travers un contrôle continu des prédictions pariétales, dans l'émergence d'une conscience d'agir non plus inférée mais véritableDuring the last five decades, the motor system has been widely studied. Yet, little is known about the neural substrate of high-level aspects of movement such as intention and awareness and how these functions are related to low-level movement execution processes. It has been suggested that the parietal cortex and supplementary motor area are involved in generating motor intentions, while premotor cortex may play a role in the emergence of motor awareness. However, the precise mechanisms implemented within each of these areas, the way they interact functionally and the nature of the signals conveyed to primary sensory and motor regions is far from being understood. Furthermore, intention and awareness of movement are also influenced by peripheral information coming from the skin, muscles and joints, and this information must be integrated to produce smooth, accurate and coordinated motor actions. Cortical and subcortical structures such as the primary motor cortex and the cerebellum are known to contain motor maps thought to contribute to motor control, learning and plasticity, but the intrinsic organization of these maps and the nature of their reciprocal relations are still unknown. In this thesis I used Direct Electrical Stimulation in patients undergoing brain surgeries to investigate how multiple motor representations are organized and identify the regions responsible for the emergence of conscious motor intention and awareness. I showed, in particular, the existence of multiple efferent maps within the cerebellum and the precentral gyrus. Furthermore, I identified the critical role of the parietal cortex for the emergence of conscious intention and -based on predictive processes- motor awareness. I also provided evidence that the premotor cortex is involved in "checking" parietal estimations, thus leading to a sense of "veridical awareness"
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Trebaul, Lena. "Développement d'outils de traitement du signal et statistiques pour l'analyse de groupe des réponses induites par des stimulations électriques corticales directes chez l'humain". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAS045/document.
Testo completoAbstract (sommario):
Introduction : La stimulation électrique directe basse fréquence est pratiquée sur des patients épileptiques pharmaco-résistants implantés avec des électrodes profondes. Elle induit de potentiels évoqués cortico-corticaux (PECC) qui permettent d’estimer la connectivité in vivo et ont permis de caractériser des réseaux locaux. Pour estimer la connectivité à l’échelle du cortex, le projet multicentrique F-TRACT vise à rassembler plusieurs centaines de patients dans une base de données pour proposer un atlas probabiliste de tractographie fonctionnelle.Méthodes : La construction de la base de données à nécessité la mise en place technique de pipelines de traitement semi-automatiques pour faciliter la gestion du nombre important de données de stéréo-électroencéphalographie (SEEG) et d’imagerie. Ces pipelines incluent des nouvelles méthodes de traitement du signal et d’apprentissage automatique, qui ont été développées pour identifier automatiquement les mauvais contacts et corriger l’artefact induit par la stimulation. Les analyses de groupe se sont basées sur des métriques des PECC et des cartes temps-fréquences des réponses à la stimulation.Résultats : La performance des méthodes développées pour le projet a été validée sur des données hétérogènes, en termes de paramètres d’acquisition et de stimulation, provenant de différents centres hospitaliers. L’atlas a été généré à partir d’un échantillon de 173 patients, fournissant une mesure de probabilité de connectivité pour 79% des connexions et d’estimer des propriétés biophysiques des fibres pour 46% d’entre elles. Son application à une sous-population de patients a permis d’étudier les réseaux impliqués dans la génération de symptômes auditifs. L’analyse de groupe oscillatoire a mis en avant l’influence de l’anatomie sur la réponse à la stimulation.Discussion : Cette thèse présente une méthodologie d’étude des PECC à l’échelle du cortex cérébral, utilisant des données hétérogènes en termes d’acquisition, de paramètres de stimulation et spatialement. L’incrémentation du nombre de patients dans l’atlas généré permettra d’étudier les interactions cortico-corticales de manière causaleIntroduction: Low-frequency direct electrical stimulation is performed in drug-resistant epileptic patients, implanted with depth electrodes. It induces cortico-cortical evoked potentials (CCEP) that allow in vivo connectivity mapping of local networks. The multicentric project F-TRACT aims at gathering data of several hundred patients in a database to build a propabilistic functional tractography atlas that estimates connectivity at the cortex level.Methods: Semi-automatic processing pipelines have been developed to handle the amount of stereo-electroencephalography (SEEG) and imaging data and store them in a database. New signal processing and machine-learning methods have been developed and included in the pipelines, in order to automatically identify bad channels and correct the stimulation artifact. Group analyses have been performed using CCEP features and time-frequency maps of the stimulation responses.Results: The new methods performance has been assessed on heterogeneous data, coming from different hospital center recording and stimulating using variable parameters. The atlas was generated from a sample of 173 patients, providing a connectivity probability value for 79% of the possible connections and estimating biophysical properties of fibers for 46% of them. The methodology was applied on patients who experienced auditory symptoms that allowed the identification of different networks involved in hallucination or illusion generation. Oscillatory group analysis showed that anatomy was driving the stimulation response pattern.Discussion: A methodology for CCEP study at the cerebral cortex scale is presented in this thesis. Heterogeneous data in terms of acquisition and stimulation parameters and spatially were used and handled. An increasing number of patients’ data will allow the maximization of the statistical power of the atlas in order to study causal cortico-cortical interactions
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Bation, Rémy. "Stimulation électrique par courant continu (tDCS) dans les Troubles Obsessionnels et Compulsifs résistants : effets cliniques et électrophysiologiques". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1344/document.
Testo completoAbstract (sommario):
Les Troubles Obsessionnels et Compulsifs (TOC) sont un trouble mental sévère et fréquemment résistant. La physiopathologie du trouble se caractérise par des anomalies au sein des boucle cortico-striato-thalamo-cortical entrainant une hyper-activité du cortex orbito-frontal, du cortex cingulaire antérieur, du putamen. Au cours des dernières années, des anomalies structurales et fonctionnelles du cervelet ont de plus été mise en évidence dans les TOC venant compléter le modèle existant.Nous avons mise au point un protocole de traitement par tDCS ciblant le cortex orbito-frontal gauche et le cervelet droit pour les TOC résistants. Dans une première étude, nous avons étudié la faisabilité de ce protocole de traitement dans une étude ouverte. Cette étude a mis en évidence une réduction significative des symptômes dans une population de patient à haut niveau de résistance. Dans une deuxième étude, nous avons évaluer l’effet de ce traitement dans un protocole randomisé, contrôlé et parallèle contre placebo. Cette étude n’a pas confirmé l’efficacité de ce protocole de traitement. Dans cette même population, nous avons au cours du protocole mesuré les paramètres d’excitabilité corticale au niveau du cortex moteur par stimulation magnétique transrânienne. Nous avons ainsi mis en évidence que la tDCS provoquait une augmentation significative des processus d’inhibition (Short Interval Cortical Inhibition : SICI ) et une diminution non significative des processus de facilitation (Intra Cortical Facilitation : ICF). L’étude des effets cliniques et électro-physiologiques de cette approche thérapeutique novatrice dans les TOC résistants n’a pas permis de confirmer son intérêt clinique malgré un impact de ce protocole sur les modifications de l’excitabilité corticale inhérentes aux troubles. Ces données ont été mise en relation avec la littérature afin de proposer des perspectives d’évolution dans l’utilisation de la tDCS dans les TOC résistantsObsessive-compulsive disorder (OCD) is a severe mental illness. OCD symptoms are often resistant to available treatments. Neurobiological models of OCD are based on an imbalance between the direct (excitatory) and indirect (inhibitory) pathway within this cortico-striato-thalamo-cortical loops, which causes hyperactivation in the orbito-frontal cortex, the cingular anterior cortex, the putamen. More recently, the role of cerebellum in the OCD physiopathology has been brought to light by studies showing structural and functional abnormalities. We proposed to use tDCS as a therapeutic tool for resistant OCD by targeting the hyperactive left orbito-frontal cortex with cathodal tDCS (assumed to decrease cortical excitability) coupled with anodal cerebellar tDCS. In a first study, we studied the feasibility of this treatment protocol in an open-trial. This study found a significant reduction in symptoms in a population with a high level of resistance. In a second study, we evaluated the effect of this treatment in a randomized-controlled trial. This study did not confirm the effectiveness of this intervention. We have assessed motor cortex cortical excitability parameters by transcranial magnetic stimulation. We thus demonstrated that the tDCS caused a significant increase of inhibition processes (Short Interval Cortical Inhibition: SICI) and a nonsignificant decrease in the facilitation processes (Intra Cortical Facilitation (ICF)). In addition, clinical improvement assessed by Clinical Global Impression at the end of the follow-up period (3 months) was positively correlated with SICI at baseline.tDCS with the cathode placed over the left OFC combined with the anode placed over the right cerebellum decreased hyper-excitability in the motor cortex but was not significantly effective in SSRI- resistant OCD patients. These works were discussed in light of the available literature to create future prospect in the field of tDCS treatment for OCD resistant patients
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Floyd, John Tyler. "Lower Extremity Transcranial Direct Current Stimulation (TDCS)| The Effect of Montage and Medium on Cortical Excitability". Thesis, University of Central Arkansas, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10686422.
Testo completoAbstract (sommario):
The dissertation consists of three parts. The first part is a systematic review of the literature regarding transcranial direct current stimulation (tDCS) and its effects on lower extremity motor behaviors and corticospinal excitability of the lower extremity representation of the motor cortex in healthy subjects. The second part investigates how different electrode montages and electrode conductance mediums affect corticospinal excitability of the tibialis anterior (TA) representation of the motor cortex in healthy subjects. The third part studies how different electrode montage and electrode conductance medium combinations affect ankle tracking accuracy in healthy subjects regarding the dominant lower extremity.
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Amadi, Ugwechi. "Transcranial stimulation to enhance cortical plasticity in the healthy and stroke-affected motor system". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:bb27ac6f-a79d-459a-b5a0-e9a209ac7132.
Testo completoAbstract (sommario):
This thesis investigated transcranial direct current stimulation (tDCS) as applied to the motor system, and its ability to modulate underlying cortical processes and resultant motor behaviours. Functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) were employed to assess the extent to which tDCS induces quantifiable changes in neural structure and function in controls and stroke patients. Modifications in the connectivity of intrinsic functional networks following tDCS application were examined using resting state fMRI. Polarity-specific changes were found: cathodal (inhibitory) tDCS increased the strength of the default mode network and increased functional coupling between major nodes within the motor network. No significant effects were found following anodal (excitatory) tDCS. Although anodal tDCS elicited only subtle changes in resting activity, it is known to produce robust modifications of behaviour. Single and paired-pulse TMS were used to investigate the neurophysiological underpinnings of these changes. Consistent with the theory of homeostatic plasticity, anodal tDCS applied prior to task performance increased GABAA-mediated cortical inhibition and worsened behaviour. The specificity of these changes suggests a central role for the mechanism of surround inhibition. A longitudinal clinical trial in chronic stroke patients was conducted to determine the utility of tDCS as an adjunct in motor rehabilitation. Serial MRI scans revealed that, when combined with motor training, anodal tDCS increased functional activity and grey matter in primarily ipsilesional motor areas. These brain changes were correlated with behavioural improvements in the stroke-affected upper limb. The laterality of connectivity at baseline, as measured by resting state activity and corticospinal tract integrity, was predictive of response to the rehabilitation program, particularly in those stroke patients who received tDCS. Asymmetry favouring the contralesional hemisphere predicted greater behavioural gains. Such results underscore the importance of re-normalisation of structure and functional activity toward the lesioned hemisphere in stroke rehabilitation.
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Qin, Jing. "The effects of transcranial direct current stimulation (tDCS) on balance control in Parkinson's disease (PD)". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211438/1/Jing_Qi_Thesis.pdf.
Testo completo
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Huang, Austin. "Cortical Stimulation Mapping of Heschl’s Gyrus in the Auditory Cortex for Tinnitus Treatment". Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2073.
Testo completoAbstract (sommario):
Tinnitus is the perception of sound in the absence of an actual sound stimulus. Recent developments have shifted the focus to the central nervous system and the neural correlate of tinnitus. Broadly, tinnitus involves cortical map rearrangement, pathological neural synchrony, and increased spontaneous firing rates. Various cortical regions, such as Heschl’s gyrus in the auditory cortex, have been found to be associated with different aspects of tinnitus, such as perception and loudness. I propose a cortical stimulation mapping study of Heschl’s gyrus using a depth and subdural electrode montage to conduct electrocorticography. This study would provide high-resolution data on abnormal frequency band oscillations characteristic of tinnitus and pinpoint regions where they occur. The validity of the neural synchrony model would also be tested in this study.
Libri sul tema "Stimulation corticale directe"
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Rotenberg, Alexander, Alvaro Pascual-Leone e Alan D. Legatt. Transcranial Electrical and Magnetic Stimulation. A cura di Donald L. Schomer e Fernando H. Lopes da Silva. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228484.003.0028.
Testo completoAbstract (sommario):
Noninvasive magnetic and electrical stimulation of cerebral cortex is an evolving field. The most widely used variant, transcranial electrical stimulation (TES), is routinely used for intraoperative monitoring. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are emerging as clinical and experimental tools. TMS has gained wide acceptance in extraoperative functional cortical mapping. TES and TMS rely on pulsatile stimulation with electrical current intensities sufficient to trigger action potentials within the stimulated cortical volume. tDCS, in contrast, is based on neuromodulatory effects of very-low-amplitude direct current conducted through the scalp. tDCS and TMS, particularly when applied in repetitive trains, can modulate cortical excitability for prolonged periods and thus are either in active clinical use or in advanced stages of clinical trials for common neurological and psychiatric disorders such as major depression and epilepsy. This chapter summarizes physiologic principles of transcranial stimulation and clinical applications of these techniques.
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Nitsche, Michael A., Andrea Antal, David Liebetanz, Nicolas Lang, Frithjof Tergau e Walter Paulus. Neuroplasticity induced by transcranial direct current stimulation. A cura di Charles M. Epstein, Eric M. Wassermann e Ulf Ziemann. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780198568926.013.0017.
Testo completoAbstract (sommario):
This article explores the use of brain stimulation as a tool of neuroplasticity. Recent studies have shown that brain stimulation with weak direct currents is a technique used to generate prolonged modifications of cortical excitability and activity. Transcranial direct current stimulation (tDCS) generates modulations of excitability. The efficacy of electric brain stimulation is defined by the combination of strength of current, size of stimulated area, and stimulation duration. The two main fields of clinical application on tDCS are: the exploration of pathological alterations of neuroplasticity in neurological and psychiatric diseases, and the evaluation of a possible clinical benefit of tDCS in these diseases. Further studies are needed to explore this area if prolonged, repetitive, or stronger stimulation protocols, for which safety has to be assured, could evolve into clinically more relevant improvement. This article reinforces the fact that brain stimulation with weak direct currents could evolve as a promising tool in neuroplasticity research.
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Nuwer, Marc R., e Stephan Schuele. Electrocorticography. A cura di Donald L. Schomer e Fernando H. Lopes da Silva. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190228484.003.0030.
Testo completoAbstract (sommario):
Electrocorticography (ECoG) is the method of recording electroencephalographic signals directly from surgically exposed cerebral cortex. It detects intraoperatively the cortical regions with substantial epileptiform interictal discharges. Direct cortical stimulation during ECoG provides a method of identifying language, motor, and sensory regions during a craniotomy. Both techniques—the identification of cortex with epileptic activity and cortex with important eloquent functional activity—help determine limits for surgical cortical resection. These are used most commonly during epilepsy and tumor surgery. Anesthetic agents can adversely affect the recording, and ECoG restricts the types of anesthesia that can be used. The amount of spiking from diffuse or remote cortical regions on ECoG can predict the success of postoperative seizure control.
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Gad, Heba, Daniel Bateman e Paul E. Holtzheimer. Neurostimulation Therapies, Side Effects, Risks, and Benefits. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199374656.003.0016.
Testo completoAbstract (sommario):
Neurostimulation therapies are an alternative for non-responders to pharmacological or psychotherapy management, as well as when first-line treatments are contraindicated for treatment of neuropsychiatric disorders in the elderly. Brain stimulation treatments for neuropsychiatric disorders include the following FDA approved treatments for major depressive disorder: electroconvulsive therapy (ECT), which remains one of the most effective therapies for several neuropsychiatric disorders; repetitive transcranial magnetic stimulation (rTMS); and vagus nerve stimulation (VNS). Deep brain stimulation (DBS);magnetic seizure therapy (MST); transcranial direct-current stimulation (tDCS); and direct cortical stimulation (DCS) are not currently FDA approved. These techniques are reviewed in this chapter with special attention to their application in older adults. Medicolegal issues of informed consent and substituted decisions for procedures are also discussed.
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Ilmoniemi, Risto J., e Jari Karhu. TMS and electroencephalography: methods and current advances. A cura di Charles M. Epstein, Eric M. Wassermann e Ulf Ziemann. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780198568926.013.0037.
Testo completoAbstract (sommario):
Electroencephalography (EEG) combined with transcranial magnetic stimulation (TMS) provides detailed real-time information about the state of the cortex. EEG requires only two to four electrodes and can be a part of most TMS studies. When used with magnetic resonance imaging (MRI) based targeting and conductor modelling, the TMS-EEG combination is a sophisticated brain-mapping tool. This article explains the mechanisms of TMS-evoked EEG. It describes the technique of recording TMS evoked EEG and the possible challenges for the same. Furthermore, it describes possible solutions to these challenges. By varying the TMS intensities, interstimulus intervals, induced current direction, and cortical targets, a rich spectrum of functional information can be obtained. Cortical excitability and connectivity can be studied directly by combining TMS with EEG or other brain-imaging methods, not only in motor, but also nonmotor, areas.
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Mason, Peggy. Basal Ganglia. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190237493.003.0025.
Testo completoAbstract (sommario):
The core function of the basal ganglia is action selection, the process of choosing between mutually exclusive actions. Under baseline or default conditions, the basal ganglia suppress movement and prevent more than one movement from occurring simultaneously. The importance of chunking and operational learning is explored through exemplary typing tasks. Pathways through the basal ganglia employ the same input and output ports. Inputs far outnumber outputs from the basal ganglia. Subcortical loops through the basal ganglia are more effective than are cortical loops. The functions of the hyperdirect, direct and indirect pathways to motor control in the skeletomotor loop are detailed. Hemiballismus, Parkinson’s disease, and Huntington’s disease are key basal ganglia disorders. The use of deep brain stimulation (DBS) of the subthalamic nucleus as a treatment for Parkinson’s disease is discussed. Finally, additional basal ganglia loops such as the oculomotor loop are introduced.
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OʼShea, Jacinta, e Matthew F. S. Rushworth. Higher visual cognition: search, neglect, attention, and eye movements. A cura di Charles M. Epstein, Eric M. Wassermann e Ulf Ziemann. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780198568926.013.0028.
Testo completoAbstract (sommario):
This article reviews the contribution of transcranial magnetic stimulation (TMS) research to the understanding of attention, eye movements, visual search, and neglect. It considers how TMS studies have confirmed, refined, or challenged prevailing ideas about the neural basis of higher visual cognition. It shows that TMS has enhanced the understanding of the location, timing, and functional roles of visual cognitive processes in the human brain. The main focus is on studies of posterior parietal cortex (PPC), with reference to recent work on the frontal eye fields (FEFs). TMS offers many advantages to complement neuropsychological patient studies to enhance the understanding of how the fronto-parietal cortical nerves function. The visuo-spatial neglect- and extinction-like deficits incurred by parietal damage have been modelled successfully using TMS. Future work might be directed at teasing apart the distinct functional roles of nodes within this frontoparietal network in different sensorimotor contexts.
Capitoli di libri sul tema "Stimulation corticale directe"
1
Polanía, Rafael, Michael A. Nitsche e Walter Paulus. "Modulation of Functional Connectivity with Transcranial Direct Current Stimulation". In Cortical Connectivity, 133–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-662-45797-9_7.
Testo completo
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Mehdorn, H. Maximillian, Simone Goebel e Arya Nabavi. "Direct Cortical Stimulation and fMRI". In fMRI, 169–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-34342-1_13.
Testo completo
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Mehdorn, Maximillian H., Simone Goebel e Arya Nabavi. "Direct Cortical Stimulation and fMRI". In fMRI, 121–26. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-68132-8_12.
Testo completo
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Mehdorn, H. Maximilian, Simone Goebel e Arya Nabavi. "Direct Cortical Stimulation and fMRI". In fMRI, 311–20. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-41874-8_21.
Testo completo
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Radhu, Natasha, Daniel M. Blumberger e Zafiris J. Daskalakis. "Cortical Inhibition and Excitation in Neuropsychiatric Disorders Using Transcranial Magnetic Stimulation". In Transcranial Direct Current Stimulation in Neuropsychiatric Disorders, 85–102. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-33967-2_6.
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Rego, Gabriel, Lucas Murrins Marques, Marília Lira da Silveira Coêlho e Paulo Sérgio Boggio. "Modulating the Social and Affective Brain with Transcranial Stimulation Techniques". In Social and Affective Neuroscience of Everyday Human Interaction, 255–70. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08651-9_15.
Testo completoAbstract (sommario):
AbstractTranscranial brain stimulation (TBS) is a term that denotes different noninvasive techniques which aim to modulate brain cortical activity through an external source, usually an electric or magnetic one. Currently, there are several techniques categorized as TBS. However, two are more used for scientific research, the transcranial magnetic stimulation (TMS) and the transcranial direct current stimulation (tDCS), which stimulate brain areas with a high-intensity magnetic field or a weak electric current on the scalp, respectively. They represent an enormous contribution to behavioral, cognitive, and social neuroscience since they reveal how delimited brain cortical areas contribute to some behavior or cognition. They have also been proposed as a feasible tool in the clinical setting since they can modulate abnormal cognition or behavior due to brain activity modulation. This chapter will present the standard methods of transcranial stimulation, their contributions to social and affective neuroscience through a few main topics, and the studies that adopted those techniques, also summing their findings.
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Ries, Stephanie K., Kesshi Jordan, Robert T. Knight e Mitchel Berger. "Lesion-Behavior Awake Mapping with Direct Cortical and Subcortical Stimulation". In Lesion-to-Symptom Mapping, 257–70. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2225-4_14.
Testo completo
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Callejón-Leblic, M. A., e Pedro C. Miranda. "A Computational Parcellated Brain Model for Electric Field Analysis in Transcranial Direct Current Stimulation". In Brain and Human Body Modeling 2020, 81–99. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_5.
Testo completoAbstract (sommario):
AbstractRecent years have seen the use of increasingly realistic electric field (EF) models to further our knowledge of the bioelectric basis of noninvasive brain techniques such as transcranial direct current stimulation (tDCS). Such models predict a poor spatial resolution of tDCS, showing a non-focal EF distribution with similar or even higher magnitude values far from the presumed targeted regions, thus bringing into doubt the classical criteria for electrode positioning. In addition to magnitude, the orientation of the EF over selected neural targets is thought to play a key role in the neuromodulation response. This chapter offers a summary of recent works which have studied the effect of simulated EF magnitude and orientation in tDCS, as well as providing new results derived from an anatomically representative parcellated brain model based on finite element method (FEM). The results include estimates of mean and peak tangential and normal EF values over different cortical regions and for various electrode montages typically used in clinical applications.
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Lei, Tingju, Ding Ma e Feng Jiang. "Mapping the Cortical Activation Changes Induced by Transcranial Direct Current Stimulation: A fNIRS-tDCS Study". In Proceedings of the 6th International Asia Conference on Industrial Engineering and Management Innovation, 355–61. Paris: Atlantis Press, 2015. http://dx.doi.org/10.2991/978-94-6239-145-1_34.
Testo completo
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Tatemoto, Tsuyoshi, Tomofumi Yamaguchi, Yohei Otaka, Kunitsugu Kondo e Satoshi Tanaka. "Anodal Transcranial Direct Current Stimulation over the Lower Limb Motor Cortex Increases the Cortical Excitability with Extracephalic Reference Electrodes". In Converging Clinical and Engineering Research on Neurorehabilitation, 829–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-34546-3_135.
Testo completoAtti di convegni sul tema "Stimulation corticale directe"
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Hong, Yirye, June Sic Kim e Chun Kee Chung. "Direct Cortical Stimulation for inducing Artificial Speech Perception: A Preliminary Study". In 2023 11th International Winter Conference on Brain-Computer Interface (BCI). IEEE, 2023. http://dx.doi.org/10.1109/bci57258.2023.10078541.
Testo completo
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Lellis, Caio de Almeida, Marco Alejandro Menacho Herbas, Glaucia Borges Dantas e Leonardo Rizier Galvão. "Transcranial Direct Current Stimulation in the Management of Refractory Symptoms of Parkinson’s Disease: A Systematic Review". In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.221.
Testo completoAbstract (sommario):
Introduction: Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique increasingly used in neurology. Objectives: To evaluate the safety and efficacy of tDCS in refractory symptoms of Parkinson’s disease (PD). Design and setting: A systematic review of the literature conducted at the Pontifical Catholic University of Goiás. Methods: A systematic review of the literature was conducted in the MedLine and Lilacs databases, with the following search strategy: “(Parkinson Disease) AND (Transcranial Direct Current Stimulation OR TDCS)”. Randomized clinical trials (10 years) were included. Results: One of the studies concluded that simultaneous tDCS of the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPC) Also, two other articles evaluated the motor response after stimulation of the left DLPC for 20 minutes, with the first realizing improved fine motor performance and attenuation of common oscillatory cortical activity in PD patients, while the second finding an improvement in balance and functional mobility when compared to placebo. Regarding cognitive and mood changes, one of the studies pointed out that a single session of tDCS on the left DLPC is insufficient to improve working memory and inhibition control. Conclusion: tDCS was shown to be a safe and effective therapeutic option in reducing gait freezing and mood disorders, as well as improving fine motor performance and cognition. It is emphasized that further studies on the subject with a larger sample are needed.
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Bernardo, Juliana Matos Ferreira, Artur Bruno Silva Gomes, Felipe Jatobá Leite Nonato de Sá, Júlia Gonçalves Ferreira e Maria Rosa da Silva. "Phantom pain: pathophysiology and therapeutic approaches". In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.496.
Testo completoAbstract (sommario):
Background: Phantom pain is a mentally debilitating neuropathy that affects post-amputees. It interferes with the independence and performance of activities, therefore affecting the quality of life. Its pathophysiology ranges from lesions in peripheral innervations, to spinal functional changes, modulation of cortical circuits and psychological factors Objectives : Demonstrate new therapeutic approaches and establish a relation with the pathophysiological mechanisms. Methods: Integrative review applying the descriptors: “phantom pain”, “physiopathology”, “post amputation pain”, “treatment”, and the Boolean operator AND. The searches were carried out at PUBMED with 142 results, at BVS with 113, and at Scielo ,showing no results. At the end, 9 papers were selected. No linguistic filters were used and articles published between 2016 and May 2020 were incorporated. Results: (1) Motor images, mental and visual representation of the limb and its function; (2) peripheral interfaces enables prosthetic control; both techniques active cortical reorganization by promoting sensory feedback to motor stimuli. (3) repetitive transcranial magnetic stimulation and (4) direct current, a non-invasive approach, for maladaptive cortical neuromodulation, in addition to stimulate peripheral innervation. In surgical interventions, (5) targeted muscle reinnervation is used in the residual nerves on amputation process to reinnervate the motor terminal of the remaining muscles, promoting nerve growth and organization. Conclusions Physiological investigation applied to treatments enables effective therapeutics, anticipating rehabilitation. The representation of images, peripheral interfaces, brain stimulation and less invasive surgical techniques.
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Sellers, Kristin K., William L. Schuerman, Heather E. Dawes, Edward F. Chang e Matthew K. Leonard. "Comparison of Common Artifact Rejection Methods applied to Direct Cortical and Peripheral Stimulation in Human ECoG". In 2019 9th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2019. http://dx.doi.org/10.1109/ner.2019.8716980.
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Thomas, Chris, Abhishek Datta e Adam Woods. "Effect of Aging on Cortical Current Flow Due to Transcranial Direct Current Stimulation: Considerations for Safety". In 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2018. http://dx.doi.org/10.1109/embc.2018.8513014.
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Khan, Bilal, Nathan Hervey, Ann Stowe, Timea Hodics e George Alexandrakis. "Use of functional near-infrared spectroscopy to monitor cortical plasticity induced by transcranial direct current stimulation". In SPIE BiOS, a cura di Nikiforos Kollias, Bernard Choi, Haishan Zeng, Hyun Wook Kang, Bodo E. Knudsen, Brian J. Wong, Justus F. Ilgner et al. SPIE, 2013. http://dx.doi.org/10.1117/12.2003446.
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Dutta, Anirban, Rahima S. Boulenouar, David Guiraud e Michael A. Nitsche. "Delineating the effects of anodal transcranial direct current stimulation on myoelectric control based on slow cortical potentials". In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6944277.
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Cao, Pengjia, Kaijie Wu, Mingjie Sun, Xinyu Chai e Qiushi Ren. "Evoked Cortical Potential and Optic Nerve Response after Direct Electrical Stimulation of the Optic Nerve in Rabbits". In 2007 IEEE/ICME International Conference on Complex Medical Engineering. IEEE, 2007. http://dx.doi.org/10.1109/iccme.2007.4381951.
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Leote, J., R. Loucao, M. Lauterbach, J. Monteiro, R. G. Nunes, C. Viegas, A. Perez-Hick, A. Silvestre e H. A. Ferreira. "Understanding network reorganization after glioma regrowth: comparing connectivity measures from functional magnetic resonance imaging to direct cortical stimulation". In 2019 IEEE 6th Portuguese Meeting on Bioengineering (ENBENG). IEEE, 2019. http://dx.doi.org/10.1109/enbeng.2019.8692523.
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Venkatakrishnan, A., J. L. Contreras-Vidal, M. Sandrini e L. G. Cohen. "Independent component analysis of resting brain activity reveals transient modulation of local cortical processing by transcranial direct current stimulation". In 2011 33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2011. http://dx.doi.org/10.1109/iembs.2011.6091998.
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