Artigos de revistas: "Direct cortical stimulation"

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Foster, Brett L., e Josef Parvizi. "Direct cortical stimulation of human posteromedial cortex". Neurology 88, n.º 7 (18 de janeiro de 2017): 685–91. http://dx.doi.org/10.1212/wnl.0000000000003607.

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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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Nitsche, Michael A., Astrid Schauenburg, Nicolas Lang, David Liebetanz, Cornelia Exner, Walter Paulus e Frithjof Tergau. "Facilitation of Implicit Motor Learning by Weak Transcranial Direct Current Stimulation of the Primary Motor Cortex in the Human". Journal of Cognitive Neuroscience 15, n.º 4 (1 de maio de 2003): 619–26. http://dx.doi.org/10.1162/089892903321662994.

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Transcranially applied weak direct currents are capable of modulating motor cortical excitability in the human. Anodal stimulation enhances excitability, cathodal stimulation diminishes it. Cortical excitability changes accompany motor learning. Here we show that weak direct currents are capable of improving implicit motor learning in the human. During performance of a serial reaction time task, the primary motor cortex, premotor, or prefrontal cortices were stimulated contralaterally to the performing hand. Anodal stimulation of the primary motor cortex resulted in increased performance, whereas stimulation of the remaining cortices had no effect. We conclude that the primary motor cortex is involved in the acquisition and early consolidation phase of implicit motor learning.

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Saleem, Yusra, Komal . e Stephen Riaz. "Transcranial Direct Current Stimulation (TDCS)." International Journal of Endorsing Health Science Research (IJEHSR) 10, n.º 4 (25 de novembro de 2022): 441–45. http://dx.doi.org/10.29052/ijehsr.v10.i4.2022.441-445.

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Transcranial direct current stimulation (TDCS) is a neuromodulatory device that is used for its ability to enhance cognitive and behavioral performance. Human studies suggest that TDCS modulates cortical excitability during stimulation by nonsynaptic changes of the cells, along with evidence that the after-effects of TDCS are driven by synaptic modification. TDCS represents a potential intervention to enhance cognition across clinical populations, including mild cognitive impairment among psychological and neurological disorders. Studies suggest that TDCS might be helpful in treating depression with appropriate current, size of electrodes, and employment of montages. TDCS opens a new perspective in treating major depressive disorder (MDD) because of its ability to modulate cortical excitability and induce long-lasting effects.

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Schuh, Lori, e Ivo Drury. "Intraoperative electrocorticography and direct cortical electrical stimulation". Seminars in Anesthesia, Perioperative Medicine and Pain 16, n.º 1 (março de 1997): 46–55. http://dx.doi.org/10.1016/s0277-0326(97)80007-4.

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Oishi, M., K. Suzuki, O. Sasaki, S. Nakazato, K. Kitazawa, T. Takao e T. Koike. "Crossed aphasia elicited by direct cortical stimulation". Neurology 67, n.º 7 (9 de outubro de 2006): 1306–7. http://dx.doi.org/10.1212/01.wnl.0000238468.84401.d4.

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Luders, H. O., I. Derakhshan, M. Oishi, K. Suzuki, O. Sasaki, S. Nakazato, K. Kitazawa, T. Takao e T. Koike. "CROSSED APHASIA ELICITED BY DIRECT CORTICAL STIMULATION". Neurology 68, n.º 19 (7 de maio de 2007): 1638–40. http://dx.doi.org/10.1212/01.wnl.0000265607.23814.05.

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Sehatpour, Pejman, Devin Adair, Stephanie Rohrig, Aleksandra Kaszowska, Alexander David, Michael Epstein, Joanna Di Costanzo e Daniel C. Javitt. "Cortical Modulation using Transcranial Direct Current Stimulation." Brain Stimulation 7, n.º 2 (março de 2014): e4. http://dx.doi.org/10.1016/j.brs.2014.01.017.

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Sehatpour, Pejman, Devin Adair, Stephanie Rohrig, Joanna DiCostanzo e Daniel C. Javitt. "Transcranial Direct Current Stimulation Modulates Cortical Networks". Brain Stimulation 10, n.º 1 (janeiro de 2017): e7. http://dx.doi.org/10.1016/j.brs.2016.11.040.

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Krings, Timo, Bradley R. Buchbinder, William E. Butler, Keith H. Chiappa, Hong J. jiang, Bruce R. Rosen e G. Rees Cosgrove. "Stereotactic Transcranial Magnetic Stimulation: Correlation with Direct Electrical Cortical Stimulation". Neurosurgery 41, n.º 6 (1 de dezembro de 1997): 1319–26. http://dx.doi.org/10.1097/00006123-199712000-00016.

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Wong, Pei-Ling, Yea-Ru Yang, Shih-Fong Huang e Ray-Yau Wang. "Effects of Transcranial Direct Current Stimulation Followed by Treadmill Training on Dual-Task Walking and Cortical Activity in Chronic Stroke: A Double-Blinded Randomized Controlled Trial". Journal of Rehabilitation Medicine 55 (21 de março de 2023): jrm00379. http://dx.doi.org/10.2340/jrm.v55.5258.

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Objective: To explore the effects of transcranial direct current stimulation followed by treadmill training on dual-task gait performance and contralesional cortical activity in chronic stroke patients.Methods: Forty-five chronic stroke participants were randomized into 3 groups: a bilateral transcranial direct current stimulation and treadmill training group; a cathodal transcranial direct current stimulation and treadmill training group; and a sham transcranial direct current stimulation and treadmill training group for 50 min per session (20 min transcranial direct current stimulation followed by 30 min treadmill training), 3 sessions per week for 4 weeks. Outcome measures included cognitive dual-task walking, motor dual-task walking, walking performance, contralesional cortical activity, and lower-extremity motor control.Results: The cathodal transcranial direct current stimulation + treadmill training group showed significantly greater improvements in cognitive dual-task walking speed than the other groups (p cathodal vs sham = 0.006, p cathodal vs bilateral = 0.016). In the cathodal transcranial direct current stimulation + treadmill training group the silent period duration increased significantly more than in the other groups (p < 0.05). Changes in motor evoked potentials in the cathodal transcranial direct current stimulation + treadmill training group were greater than those in the sham transcranial direct current stimulation + treadmill training group (p < 0.05). No significant changes were observed in the bilateral transcranial direct current stimulation + treadmill training group.Conclusion: Cathodal transcranial direct current stimulation followed by treadmill training is an effective intervention for improving cognitive dual-task walking and modulating contralesional cortical activity in chronic stroke. No beneficial effects were observed after bilateral transcranial direct current stimulation and treadmill training.LAY ABSTRACTDual-task walking is essential for daily functioning, both at home and socially. This study explored the effects of transcranial direct current stimulation followed by treadmill training on dual-task gait performance and contralesional cortical activity in chronic stroke patients. A total of 45 chronic stroke patients were randomized to 1 of 3 groups: a bilateral transcranial direct current stimulation and treadmill training group, a cathodal transcranial direct current stimulation and treadmill training group, or a sham transcranial direct current stimulation and treadmill training group for 50 min per session, 3 sessions per week for 4 weeks. Cognitive dual-task walking, motor dual-task walking, walking performance, contralesional cortical activity, and lower-extremity motor control of the affected side were measured before and after the intervention. The results show that cathodal transcranial direct current stimulation followed by treadmill training is an effective intervention for improving cognitive dual-task walking and modulating contralesional cortical activityin individuals with chronic stroke.

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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.º 3 (junho de 1987): 315–26. http://dx.doi.org/10.1038/jcbfm.1987.69.

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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 (abril de 2024): 67. http://dx.doi.org/10.1227/neu.0000000000002809_243.

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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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R.*, Rusina, Barek S., Vaculín S., Azerad J. e Rokyta R. "Cortical stimulation and tooth pulp evoked potentials in rats: A model of direct anti-nociception". Acta Neurobiologiae Experimentalis 70, n.º 1 (31 de março de 2010): 47–55. http://dx.doi.org/10.55782/ane-2010-1773.

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While the effect of cortex stimulation on pain control is widely accepted, its physiological basis remains poorly understood. We chose an animal model of pain to study the influence of sensorimotor cortex stimulation on tooth pulp stimulation evoked potentials (TPEPs). Fifteen awake rats implanted with tooth pulp, cerebral cortex, and digastric muscle electrodes were divided into three groups, receiving 60 Hz, 40 Hz and no cortical stimulation, respectively. TPEPs were recorded before, one, three and five hours after continuous stimulation. We observed an inverse relationship between TPEP amplitude and latency with increasing tooth pulp stimulation. The amplitudes of the early components of TPEPs increased and their latency decreased with increasing tooth pulp stimulation intensity. Cortical stimulation decreased the amplitude of TPEPs; however, neither the latencies of TPEPs nor the jaw-opening reflex were changed after cortical stimulation. The decrease in amplitude of TPEPs after cortical stimulation may reflect its anti-nociceptive effect.

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Fregni, Felipe, Paulo S. Boggio, Marcelo C. Santos, Moises Lima, Adriana L. Vieira, Sergio P. Rigonatti, M. Teresa A. Silva, Egberto R. Barbosa, Michael A. Nitsche e Alvaro Pascual-Leone. "Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson's disease". Movement Disorders 21, n.º 10 (2006): 1693–702. http://dx.doi.org/10.1002/mds.21012.

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Biton, Victor, Miguel E. Fiol, John R. Gates e Robert E. Maxwell. "Inhibitory Sensory Locus Defined by Direct Cortical Stimulation". Journal of Clinical Neurophysiology 5, n.º 4 (outubro de 1988): 338. http://dx.doi.org/10.1097/00004691-198810000-00040.

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Sehm, Bernhard, Alexander Schäfer, Judy Kipping, Daniel Margulies, Virginia Conde, Marco Taubert, Arno Villringer e Patrick Ragert. "Dynamic modulation of intrinsic functional connectivity by transcranial direct current stimulation". Journal of Neurophysiology 108, n.º 12 (15 de dezembro de 2012): 3253–63. http://dx.doi.org/10.1152/jn.00606.2012.

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Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique capable of modulating cortical excitability and thereby influencing behavior and learning. Recent evidence suggests that bilateral tDCS over both primary sensorimotor cortices (SM1) yields more prominent effects on motor performance in both healthy subjects and chronic stroke patients than unilateral tDCS over SM1. To better characterize the underlying neural mechanisms of this effect, we aimed to explore changes in resting-state functional connectivity during both stimulation types. In a randomized single-blind crossover design, 12 healthy subjects underwent functional magnetic resonance imaging at rest before, during, and after 20 min of unilateral, bilateral, and sham tDCS stimulation over SM1. Eigenvector centrality mapping (ECM) was used to investigate tDCS-induced changes in functional connectivity patterns across the whole brain. Uni- and bilateral tDCS over SM1 resulted in functional connectivity changes in widespread brain areas compared with sham stimulation both during and after stimulation. Whereas bilateral tDCS predominantly modulated changes in primary and secondary motor as well as prefrontal regions, unilateral tDCS affected prefrontal, parietal, and cerebellar areas. No direct effect was seen under the stimulating electrode in the unilateral condition. The time course of changes in functional connectivity in the respective brain areas was nonlinear and temporally dispersed. These findings provide evidence toward a network-based understanding regarding the underpinnings of specific tDCS interventions.

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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 de abril de 2021): 1–10. http://dx.doi.org/10.1155/2021/8855055.

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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.

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Oda, Nobuhito, Masami Ishii e Bong-Kyun Kim. "The efficacy of direct motor cortical stimulation for sensori-motor cortical lesions". Clinical Neurology and Neurosurgery 99 (julho de 1997): S33. http://dx.doi.org/10.1016/s0303-8467(97)81392-3.

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Nitsche, M. A., S. Doemkes, T. Karaköse, A. Antal, D. Liebetanz, N. Lang, F. Tergau e W. Paulus. "Shaping the Effects of Transcranial Direct Current Stimulation of the Human Motor Cortex". Journal of Neurophysiology 97, n.º 4 (abril de 2007): 3109–17. http://dx.doi.org/10.1152/jn.01312.2006.

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Transcranial DC stimulation (tDCS) induces stimulation polarity-dependent neuroplastic excitability shifts in the human brain. Because it accomplishes long-lasting effects and its application is simple, it is used increasingly. However, one drawback is its low focality, caused by 1) the large stimulation electrode and 2) the functionally effective reference electrode, which is also situated on the scalp. We aimed to increase the focality of tDCS, which might improve the interpretation of the functional effects of stimulation because it will restrict its effects to more clearly defined cortical areas. Moreover, it will avoid unwanted reversed effects of tDCS under the reference electrode, which is of special importance in clinical settings, when a homogeneous shift of cortical excitability is needed. Because current density (current strength/electrode size) determines the efficacy of tDCS, increased focality should be accomplished by 1) reducing stimulation electrode size, but keeping current density constant; or 2) increasing reference electrode size under constant current strength. We tested these hypotheses for motor cortex tDCS. The results show that reducing the size of the motor cortex DC-stimulation electrode focalized the respective tDCS-induced excitability changes. Increasing the size of the frontopolar reference electrode rendered stimulation over this cortex functionally inefficient, but did not compromise the tDCS-generated motor cortical excitability shifts. Thus tDCS-generated modulations of cortical excitability can be focused by reducing the size of the stimulation electrode and by increasing the size of the reference electrode. For future applications of tDCS, such paradigms may help to achieve more selective tDCS effects.

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Cohen, L. G., S. Sato, K. Kufta e M. Hallett. "Attenuation of somatosensory perception by transcranial magnetic stimulation and direct cortical stimulation". Electroencephalography and Clinical Neurophysiology 75 (janeiro de 1990): S25—S26. http://dx.doi.org/10.1016/0013-4694(90)91809-4.

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Noll, Kyle, Priscella Asman, Katherine Connelly, Israt Tasnim, Chandra Swamy, Chibawanye Ene, Tummala Sudhakar et al. "NCOG-14. INTRAOPERATIVE COGNITIVE-LINGUISTIC MAPPING GUIDED BY VISUALIZATION OF GAMMA BAND MODULATION ELECTROCORTICOGRAMS: PROOF OF CONCEPT IN A PATIENT WITH LEFT TEMPORAL AND OCCIPITAL LOW-GRADE ASTROCYTOMA". Neuro-Oncology 24, Supplement_7 (1 de novembro de 2022): vii200. http://dx.doi.org/10.1093/neuonc/noac209.767.

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Abstract OBJECTIVE Determine the feasibility and preliminary utility of a novel approach to intraoperative brain mapping guided by visualization of electrocorticography (ECoG) heat maps. METHODS A 39-year-old male with a biopsy-proven left posterior temporal and occipital WHO grade II IDH-mutant astrocytoma underwent awake craniotomy with intraoperative language mapping. Language mapping utilized a dual iPad stimulus presentation system (NeuroMapper) coupled to a portable real-time neural signal processing system capable of both recording cortical activity and delivering direct cortical stimulation in a closed-loop fashion. An ECoG grid (4x8 with 1cm pitch) which covered the majority of the left temporal lobe was used to assess oscillatory cortical activity during administration of language paradigms including object, action, auditory descriptive, and written descriptive naming. ECoG recording and cortical stimulation were synchronized with stimulus presentation via a photosensor attached to the patient-facing tablet. Gamma band modulations in response to language paradigms at each electrode were processed in real-time and visualized as heat maps in MATLAB/Simulink. Following recording and visualization, bipolar direct cortical stimulation from the grid was conducted for each neighboring electrode pair (up to an intensity of 6 mA) during administration of language tasks. RESULTS Despite mild fluent aphasia, a large set of reliable baseline stimuli were obtained for the language mapping paradigms. All naming paradigms resulted in strongest heat map activation at electrode 12 located in the anterior to mid superior temporal gyrus. During stimulation, consistent speech arrest was observed across all paradigms when stimulating electrode pair 11-12, indicating good correspondence with ECoG heat map recordings. Additionally, this region corresponded well with posterior language network representation via resting-state fMRI. CONCLUSION Intraoperative real-time visualization of task-based ECoG gamma band modulation is feasible and may help identify targets for direct cortical stimulation. If validated, this may improve the efficiency and accuracy of intraoperative language mapping.

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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.º 9 (1 de maio de 2012): 1576–92. http://dx.doi.org/10.1152/japplphysiol.00967.2011.

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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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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.º 14 (9 de julho de 2024): 7546. http://dx.doi.org/10.3390/ijms25147546.

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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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Chadaide, Z., S. Arlt, A. Antal, MA Nitsche, N. Lang e W. Paulus. "Transcranial Direct Current Stimulation Reveals Inhibitory Deficiency In Migraine". Cephalalgia 27, n.º 7 (julho de 2007): 833–39. http://dx.doi.org/10.1111/j.1468-2982.2007.01337.x.

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The issue of interictal excitability of cortical neurons in migraine patients is controversial: some studies have reported hypo-, others hyperexcitability. The aim of the present study was to observe the dynamics of this basic interictal state by further modulating the excitability level of the visual cortex using transcranial direct current stimulation (tDCS) in migraineurs with and without aura. In healthy subjects anodal tDCS decreases, cathodal stimulation increases transcranial magnetic stimulation (TMS)-elicited phosphene thresholds (PT), which is suggested as a representative value of visual cortex excitability. Compared with healthy controls, migraine patients tended to show lower baseline PT values, but this decrease failed to reach statistical significance. Anodal stimulation decreased phosphene threshold in migraineurs similarly to controls, having a larger effect in migraineurs with aura. Cathodal stimulation had no significant effect in the patient groups. This result strengthens the notion of deficient inhibitory processes in the cortex of migraineurs, which is selectively revealed by activity-modulating cortical input.

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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.º 12 (20 de junho de 2022): 6850. http://dx.doi.org/10.3390/ijms23126850.

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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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Lim, Sung Hyuk, e Min Hwan Jang. "Technical Considerations of Effective Direct Cortical and Subcortical Stimulation". Korean Journal of Clinical Laboratory Science 54, n.º 2 (30 de junho de 2022): 157–62. http://dx.doi.org/10.15324/kjcls.2022.54.2.157.

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Bialik, Paul Shkurovich. "38. Mapping eloquent cortical areas with direct electrical stimulation". Clinical Neurophysiology 127, n.º 9 (setembro de 2016): e311. http://dx.doi.org/10.1016/j.clinph.2016.05.313.

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Speth, C., J. Speth e T. Harley. "Transcranial direct current stimulation and cortical indicators of relaxation". Brain Stimulation 8, n.º 2 (março de 2015): 405. http://dx.doi.org/10.1016/j.brs.2015.01.290.

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Sun, Yan, Sameer C. Dhamne, Alejandro Carretero‐Guillén, Ricardo Salvador, Marti C. Goldenberg, Brianna R. Godlewski, Alvaro Pascual‐Leone et al. "Drug‐Responsive Inhomogeneous Cortical Modulation by Direct Current Stimulation". Annals of Neurology 88, n.º 3 (25 de julho de 2020): 489–502. http://dx.doi.org/10.1002/ana.25822.

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Cherney, Leora R. "Cortical Stimulation and Aphasia: The State of the Science". Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders 18, n.º 1 (abril de 2008): 33–39. http://dx.doi.org/10.1044/nnsld18.1.33.

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Abstract Purpose: Biological approaches to aphasia rehabilitation involve procedures aimed to alter brain anatomy and physiology so that language function can be restored. One such approach is the application of electrical stimulation to the cerebral cortex to facilitate brain plasticity and enhance stroke recovery. Method: This article discusses the rationale for the application of cortical stimulation and reviews three different methods of delivering cortical brain stimulation — repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and epidural cortical stimulation. Each of these methods has been applied to the rehabilitation of language after stroke, and some of the key studies that have addressed the use of cortical stimulation as a potential treatment for post-stroke aphasia are described. Conclusions: Pilot results suggest a potential role for cortical stimulation as an adjuvant strategy in aphasia rehabilitation. Further investigation of each method of stimulation and its impact on language recovery is warranted. Suggestions for the direction of future research are discussed.

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Alagapan, Sankaraleengam, Stephen L. Schmidt, Jérémie Lefebvre, Eldad Hadar, Hae Won Shin e Flavio Frӧhlich. "Modulation of Cortical Oscillations by Low-Frequency Direct Cortical Stimulation Is State-Dependent". PLOS Biology 14, n.º 3 (29 de março de 2016): e1002424. http://dx.doi.org/10.1371/journal.pbio.1002424.

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Matsumoto, Riki, Masako Kinoshita, Junya Taki, Takefumi Hitomi, Nobuhiro Mikuni, Hiroshi Shibasaki, Hidenao Fukuyama, Nobuo Hashimoto e Akio Ikeda. "In Vivo Epileptogenicity of Focal Cortical Dysplasia: A Direct Cortical Paired Stimulation Study". Epilepsia 46, n.º 11 (novembro de 2005): 1744–49. http://dx.doi.org/10.1111/j.1528-1167.2005.00284.x.

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Jacobs, M., A. Premji e A. J. Nelson. "Plasticity-Inducing TMS Protocols to Investigate Somatosensory Control of Hand Function". Neural Plasticity 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/350574.

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Hand function depends on sensory feedback to direct an appropriate motor response. There is clear evidence that somatosensory cortices modulate motor behaviour and physiology within primary motor cortex. However, this information is mainly from research in animals and the bridge to human hand control is needed. Emerging evidence in humans supports the notion that somatosensory cortices modulate motor behaviour, physiology and sensory perception. Transcranial magnetic stimulation (TMS) allows for the investigation of primary and higher-order somatosensory cortices and their role in control of hand movement in humans. This review provides a summary of several TMS protocols in the investigation of hand control via the somatosensory cortices. TMS plasticity inducing protocols reviewed include paired associative stimulation, repetitive TMS, theta-burst stimulation as well as other techniques that aim to modulate cortical excitability in sensorimotor cortices. Although the discussed techniques may modulate cortical excitability, careful consideration of experimental design is needed to isolate factors that may interfere with desired results of the plasticity-inducing protocol, specifically events that may lead to metaplasticity within the targeted cortex.

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Kunori, Nobuo, e Ichiro Takashima. "Cortical direct current stimulation improves signal transmission between the motor cortices of rats". Neuroscience Letters 741 (janeiro de 2021): 135492. http://dx.doi.org/10.1016/j.neulet.2020.135492.

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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.º 8 (agosto de 2003): 900–910. http://dx.doi.org/10.1097/01.wcb.0000076702.71231.f2.

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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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Arif, Yasra, Rachel K. Spooner, Alex I. Wiesman, Amy L. Proskovec, Michael T. Rezich, Elizabeth Heinrichs-Graham e Tony W. Wilson. "Prefrontal Multielectrode Transcranial Direct Current Stimulation Modulates Performance and Neural Activity Serving Visuospatial Processing". Cerebral Cortex 30, n.º 9 (11 de maio de 2020): 4847–57. http://dx.doi.org/10.1093/cercor/bhaa077.

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Abstract The dorsolateral prefrontal cortex (DLPFC) is known to play a critical role in visuospatial attention and processing, but the relative contribution of the left versus right DLPFC remains poorly understood. We applied multielectrode transcranial direct-current stimulation (ME-tDCS) to the left and right DLPFC to investigate its net impact on behavioral performance and population-level neural activity. The primary hypothesis was that significant laterality effects would be observed in regard to behavior and neural oscillations. Twenty-five healthy adults underwent three visits (left, right, and sham ME-tDCS). Following stimulation, participants completed a visuospatial processing task during magnetoencephalography (MEG). Statistically significant oscillatory events were imaged, and time series were then extracted from the peak voxels of each response. Behavioral findings indicated differences in reaction time and accuracy, with left DLPFC stimulation being associated with slower responses and decreased accuracy compared to right stimulation. Left DLPFC stimulation was also associated with increases in spontaneous theta and decreases in gamma within occipital cortices relative to both right and sham stimulation, while connectivity among DLPFC and visual cortices was generally increased contralateral to stimulation. These data suggest spectrally specific modulation of spontaneous cortical activity at the network-level by ME-tDCS, with distinct outcomes based on the laterality of stimulation.

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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.

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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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Jahangiri, Faisal R., Jonathan H. Sherman, Jason Sheehan, Mark Shaffrey, Aaron S. Dumont, Michael Vengrow e Francisco Vega-Bermudez. "Limiting the Current Density During Localization of the Primary Motor Cortex by Using a Tangential-Radial Cortical Somatosensory Evoked Potentials Model, Direct Electrical Cortical Stimulation, and Electrocorticography". Neurosurgery 69, n.º 4 (10 de maio de 2011): 893–98. http://dx.doi.org/10.1227/neu.0b013e3182230ac3.

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Abstract BACKGROUND: Traditionally, the dual-radial model, which requires high cortical stimulation intensities and may evoke intraoperative seizures, is used for mapping during resection of lesions within or near the central sulcus. OBJECTIVE: To examine the potential utility of using the multimodal tangential-radial triphasic model, which may increase the accuracy and reliability of cortical mapping at lower stimulation intensities. METHODS: We performed a retrospective review of intracranial neuromonitoring cases at the University of Virginia. The tangential-radial triphasic model used direct electrical cortical stimulation (DECS), electrocorticography, and somatosensory evoked potentials with an additional P25 peak for waveform interpretation, instead of the older dual-radial model with N20 and P30 peaks alone. The central sulcus and sensory cortex were localized by generating multiple sensory maps. DECS with 50-Hz frequency was applied. Electrocorticography was used for detection of afterdischarges. RESULTS: Fifteen consecutive intracranial cases were identified. The patients consisted of 8 males and 7 females ranging in age from 12 to 74 years (median, 53 years). Fourteen patients had an intra-axial cortical mass, and 1 patient had a cortical arteriovenous malformation. The DECS thresholds ranged from 3.7 to 12 mA (median, 6.2 mA). Localization of motor and sensory cortices was accurately performed at low thresholds with bipolar DECS in all patients. Intraoperative seizures occurred in 1 patient (7%), and new permanent postoperative functional deficits occurred in 1 patient (7%). CONCLUSION: Our mapping technique appears safe and reliable for resection near the central sulcus. The tangential-radial triphasic model allows for lower stimulation intensities, reducing the risk of intraoperative seizures.

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Loizon, Marine, Philippe Ryvlin, Benoit Chatard, Julien Jung, Romain Bouet, Marc Guenot, Laure Mazzola, Laurent Bezin e Sylvain Rheims. "Transient hypoxemia induced by cortical electrical stimulation". Neurology 94, n.º 22 (5 de maio de 2020): e2323-e2336. http://dx.doi.org/10.1212/wnl.0000000000009497.

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ObjectiveTo identify which cortical regions are associated with direct electrical stimulation (DES)–induced alteration of breathing significant enough to impair pulse oximetry (SpO2).MethodsEvolution of SpO2 after 1,352 DES was analyzed in 75 patients with refractory focal epilepsy who underwent stereo-EEG recordings. For each DES, we assessed the change in SpO2 from 30 seconds prior to DES onset to 120 seconds following the end of the DES. The primary outcome was occurrence of stimulation-induced transient hypoxemia as defined by decrease of SpO2 ≥5% within 60 seconds after stimulation onset as compared to pre-DES SpO2 or SpO2 nadir <90% during at least 5 seconds. Localization of the stimulated contacts was defined according to MarsAtlas brain parcellation and Freesurfer segmentation.ResultsA stimulation-induced transient hypoxemia was observed after 16 DES (1.2%) in 10 patients (13%), including 6 in whom SpO2 nadir was <90%. Among these 16 DES, 7 (44%) were localized within the perisylvian cortex. After correction for individual effects and the varying number of DES contributed by each person, significant decrease of SpO2 was significantly associated with the localization of DES (p = 0.019).ConclusionThough rare, a significant decrease of SpO2 could be elicited by cortical direct electrical stimulation outside the temporo-limbic structures, most commonly after stimulation of the perisylvian cortex.

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Karakis, Ioannis, Beth A. Leeman-Markowski, Catherine L. Leveroni, Ronan D. Kilbride, Sydney S. Cash, Emad N. Eskandar e Mirela V. Simon. "Intra-stimulation discharges: An overlooked cortical electrographic entity triggered by direct electrical stimulation". Clinical Neurophysiology 126, n.º 5 (maio de 2015): 882–88. http://dx.doi.org/10.1016/j.clinph.2014.08.011.

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Weaver, Kurt E., David J. Caldwell, Jeneva A. Cronin, Chao‐Hung Kuo, Michael Kogan, Brady Houston, Victor Sanchez et al. "Concurrent Deep Brain Stimulation Reduces the Direct Cortical Stimulation Necessary for Motor Output". Movement Disorders 35, n.º 12 (11 de setembro de 2020): 2348–53. http://dx.doi.org/10.1002/mds.28255.

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Picht, Thomas, Sven Mularski, Bjoern Kuehn, Peter Vajkoczy, Theodoros Kombos e Olaf Suess. "Navigated Transcranial Magnetic Stimulation for Preoperative Functional Diagnostics in Brain Tumor Surgery". Operative Neurosurgery 65, suppl_6 (1 de dezembro de 2009): ons93—ons99. http://dx.doi.org/10.1227/01.neu.0000348009.22750.59.

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Abstract Objective: Transcranial magnetic stimulation (TMS) is a noninvasive method for analyzing cortical function. To utilize TMS for presurgical functional diagnostics, the magnetic impulse must be precisely targeted by stereotactically positioning the coil. The aim of this study was to evaluate the usefulness of TMS for operation planning when combined with a sensor-based electromagnetic navigation system (nTMS). Methods: Preoperative functional mapping with nTMS was performed in 10 patients with rolandic tumors. Intraoperative mapping was performed with the “gold standard” of direct cortical stimulation. Stimulation was performed in the same predefined 5-mm raster for both modalities, and the results were compared. Results: In regard to the 5-mm mapping raster, the centers of gravity of nTMS and direct cortical stimulation were located at the same spot in 4 cases and at neighboring spots in the remaining 6 cases. The mean distance between the tumor and the nearest motor response (“safety margin”) was 7.9 mm (range, 5–15 mm; standard deviation, 3.2 mm) for nTMS and 6.6 mm (range, 0–12 mm; standard deviation, 3.4 mm) for direct cortical stimulation. Conclusion: nTMS allowed for reliable, precise application of the magnetic impulse, and the peritumoral somatotopy corresponded well between the 2 modalities in all 10 cases. nTMS is a promising method for preoperative functional mapping in motor cortex tumor surgery.

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Gomez-Tames, Jose, Akimasa Hirata, Manabu Tamura e Yoshihiro Muragaki. "Corticomotoneuronal Model for Intraoperative Neurophysiological Monitoring During Direct Brain Stimulation". International Journal of Neural Systems 29, n.º 01 (10 de janeiro de 2019): 1850026. http://dx.doi.org/10.1142/s0129065718500260.

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Intraoperative neurophysiological monitoring during brain surgery uses direct cortical stimulation to map the motor cortex by recording muscle activity induced by the excitation of alpha motor neurons (MNs). Computational models have been used to understand local brain stimulation. However, a computational model revealing the stimulation process from the cortex to MNs has not yet been proposed. Thus, the aim of the current study was to develop a corticomotoneuronal (CMN) model to investigate intraoperative stimulation during surgery. The CMN combined the following three processes into one system for the first time: (1) induction of an electric field in the brain based on a volume conductor model; (2) activation of pyramidal neuron (PNs) with a compartment model; and (3) formation of presynaptic connections of the PNs to MNs using a conductance-based synaptic model coupled with a spiking model. The implemented volume conductor model coupled with the axon model agreed with experimental strength-duration curves. Additionally, temporal/spatial and facilitation effects of CMN synapses were implemented and verified. Finally, the integrated CMN model was verified with experimental data. The results demonstrated that our model was necessary to describe the interaction between frequency and pulses to assess the difference between low-frequency and multi-pulse high-frequency stimulation in cortical stimulation. The proposed model can be used to investigate the effect of stimulation parameters on the cortex to optimize intraoperative monitoring.

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Volf, Nadia. "Somatosensory Evoked Potentials in the Investigation of Auricular Acupuncture Points". Acupuncture in Medicine 18, n.º 1 (junho de 2000): 2–9. http://dx.doi.org/10.1136/aim.18.1.2.

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A preliminary study correlating the wrist and gall bladder body areas with their auricular acupuncture points, through recording the somatosensory evoked potentials (SEP) at the corresponding brain localisation, showed that stimulation of the “Wrist” auricular point activates the primary cortical somatosensory area of the upper extremity on the contralateral hemisphere in a similar way to direct median nerve stimulation. A “placebo” point 5 to 8mm from the “Wrist” auricular point was used as a control: no activation in the brain area was observed. In patients with post-stroke hemiplegia, SEP traces obtained both by direct median nerve stimulation at the wrist, and by stimulation of the “wrist” auricular point, were altered in a similar manner and only on the damaged side. Similarly, “gall bladder” auricular point stimulation activates the corresponding cortical somatosensory area in the same way as direct stimulation of the T7 intercostal nerve. Again, a “placebo” point, 5 to 8mm away from the “Gall bladder” auricular point, was used as a control, and activation in the brain area was not observed. Also, in patients with cholelithiasis, both the SEP traces evoked by T7 direct intercostal nerve stimulation and those evoked by “Gall bladder” auricular point stimulation were altered in the same manner. These results demonstrate that there is correlation between the activation of specific areas of brain cortex and stimulation of their corresponding auricular acupuncture points, and indicate a convergence into the same cortical somatosensory area of nerve impulses coming from the body organ itself and from the auricular point corresponding to that organ. This might be taken as suggesting neurological support for a functional somatic relationship of auricular points.

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Lang, Nicolas, Michael A. Nitsche, Michele Dileone, Paolo Mazzone, Javier De Andrés-Arés, Luis Diaz-Jara, Walter Paulus, Vincenzo Di Lazzaro e Antonio Oliviero. "Transcranial direct current stimulation effects on I-wave activity in humans". Journal of Neurophysiology 105, n.º 6 (junho de 2011): 2802–10. http://dx.doi.org/10.1152/jn.00617.2010.

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Transcranial direct current stimulation (tDCS) of the human cerebral cortex modulates cortical excitability noninvasively in a polarity-specific manner: anodal tDCS leads to lasting facilitation and cathodal tDCS to inhibition of motor cortex excitability. To further elucidate the underlying physiological mechanisms, we recorded corticospinal volleys evoked by single-pulse transcranial magnetic stimulation of the primary motor cortex before and after a 5-min period of anodal or cathodal tDCS in eight conscious patients who had electrodes implanted in the cervical epidural space for the control of pain. The effects of anodal tDCS were evaluated in six subjects and the effects of cathodal tDCS in five subjects. Three subjects were studied with both polarities. Anodal tDCS increased the excitability of cortical circuits generating I waves in the corticospinal system, including the earliest wave (I1 wave), whereas cathodal tDCS suppressed later I waves. The motor evoked potential (MEP) amplitude changes immediately following tDCS periods were in agreement with the effects produced on intracortical circuitry. The results deliver additional evidence that tDCS changes the excitability of cortical neurons.

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Fazaila Ehsaan, Nazia Mumtaz e Ghulam Saqulain. "Novel therapeutic techniques for post stroke aphasia: a narrative review". Journal of the Pakistan Medical Association 72, n.º 01 (7 de maio de 2022): 121. http://dx.doi.org/10.47391/jpma.2277.

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Aphasia, a language disorder, results from stroke involving cortical and subcortical structures. Aphasia lacks effective standardized treatment. Neuroimaging and behavioral research indicate that some interventions promote neuroplasticity. Research has suggested that noninvasive brain stimulation may be effective causing functional reorganization of language areas between both hemispheres. This reorganization evolves from different researches exploring novel procedures including transcranial magnetic stimulation and intracranial direct current stimulation, which may modulate cortical activity in aphasia. This paper reviewed these techniques while examining the casual role of specific regions of brain and the understanding of mechanism underlying for facilitator treatment effects of brain stimulation. For this literature was searched using search engines and databases like Medline, Web of Science and bibliography of published studies using “noninvasive brain stimulation, Post-stroke aphasia, Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation” as keywords. Of the 175 publications downloaded, 40 full text English publications were used for literature review.

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Ley, Miguel, Nazaret Peláez, Alessandro Principe, Klaus Langohr, Riccardo Zucca e Rodrigo Rocamora. "Validation of direct cortical stimulation in presurgical evaluation of epilepsy". Clinical Neurophysiology 137 (maio de 2022): 38–45. http://dx.doi.org/10.1016/j.clinph.2022.02.006.

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Kyuma, Yoshikazu, Akimune Hayashi e Satoshi Nishimura. "Intraoperative cortical mapping by direct brain stimulation under local anesthesia". Clinical Neurology and Neurosurgery 99 (julho de 1997): S190—S191. http://dx.doi.org/10.1016/s0303-8467(97)82155-5.

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Sala, Francesco. "Penfield’s stimulation for direct cortical motor mapping: An outdated technique?" Clinical Neurophysiology 129, n.º 12 (dezembro de 2018): 2635–37. http://dx.doi.org/10.1016/j.clinph.2018.09.021.

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Leote, Joao, Ricardo Loução, Catarina Viegas, Martin Lauterbach, António Perez-Hick, Joana Monteiro, Rita G. Nunes e Hugo A. Ferreira. "Impact of Navigated Task-specific fMRI on Direct Cortical Stimulation". Journal of Neurological Surgery Part A: Central European Neurosurgery 81, n.º 06 (1 de julho de 2020): 555–64. http://dx.doi.org/10.1055/s-0040-1712496.

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Abstract Background and Study Aims Cortical mapping (CM) with direct cortical stimulation (DCS) in awake craniotomy is used to preserve cognitive functions such as language. Nevertheless, patient collaboration during this procedure is influenced by previous neurological symptoms and growing discomfort with DCS duration. Our study aimed to evaluate the impact of navigated task-specific functional magnetic resonance imaging (nfMRI) on the practical aspects of DCS. Material and Methods We recruited glioma patients scheduled for awake craniotomy for prior fMRI-based CM, acquired during motor and language tasks (i.e., verb generation, semantic and syntactic decision tasks). Language data was combined to generate a probabilistic map indicating brain regions activated with more than one paradigm. Presurgical neurophysiological language tests (i.e., verb generation, picture naming, and semantic tasks) were also performed. We considered for subsequent study only the patients with a minimum rate of correct responses of 50% in all tests. These patients were then randomized to perform intraoperative language CM either using the multimodal approach (mCM), using nfMRI and DCS combined, or electrical CM (eCM), with DCS alone. DCS was done while the patient performed picture naming and nonverbal semantic decision tasks. Methodological features such as DCS duration, number of stimuli, total delivered stimulus duration per task, and frequency of seizures were analyzed and compared between groups. The correspondence between positive responses obtained with DCS and nfMRI was also evaluated. Results Twenty-one surgeries were included, thirteen of which using mCM (i.e., test group). Patients with lower presurgical neuropsychological performance (correct response rate between 50 and 80% in language tests) showed a decreased DCS duration in comparison with the control group. None of the compared methodological features showed differences between groups. Correspondence between DCS and nfMRI was 100/84% in the identification of the precentral gyrus for motor function/opercular frontal inferior gyrus for language function, respectively. Conclusion Navigated fMRI data did not influence DCS in practice. Presurgical language disturbances limited the applicability of DCS mapping in awake surgery.

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