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Sample records for brain stimulation electrodes

  1. Fiber-based tissue identification for electrode placement in deep brain stimulation neurosurgery (Conference Presentation)

    Science.gov (United States)

    DePaoli, Damon T.; Lapointe, Nicolas; Goetz, Laurent; Parent, Martin; Prudhomme, Michel; Cantin, Léo.; Galstian, Tigran; Messaddeq, Younès.; Côté, Daniel C.

    2016-03-01

    Deep brain stimulation's effectiveness relies on the ability of the stimulating electrode to be properly placed within a specific target area of the brain. Optical guidance techniques that can increase the accuracy of the procedure, without causing any additional harm, are therefore of great interest. We have designed a cheap optical fiber-based device that is small enough to be placed within commercially available DBS stimulating electrodes' hollow cores and that is capable of sensing biological information from the surrounding tissue, using low power white light. With this probe we have shown the ability to distinguish white and grey matter as well as blood vessels, in vitro, in human brain samples and in vivo, in rats. We have also repeated the in vitro procedure with the probe inserted in a DBS stimulating electrode and found the results were in good agreement. We are currently validating a second fiber optic device, with micro-optical components, that will result in label free, molecular level sensing capabilities, using CARS spectroscopy. The final objective will be to use this data in real time, during deep brain stimulation neurosurgery, to increase the safety and accuracy of the procedure.

  2. Numerical Characterization of Intraoperative and Chronic Electrodes in Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Alessandra ePaffi

    2015-02-01

    Full Text Available Intraoperative electrode is used in the Deep Brain stimulation (DBS technique to pinpoint the brain target and to choose the best parameters for the stimulating signal. However, when the intraoperative electrode is replaced with the chronic one, the observed effects do not always coincide with predictions.To investigate the causes of such discrepancies, in this work, a 3D model of the basal ganglia has been considered and realistic models of both intraoperative and chronic electrodes have been developed and numerically solved.Results of simulations on the electric potential and the activating function along neuronal fibers show that the different geometries and sizes of the two electrodes do not change shapes and polarities of these functions, but only the amplitudes. A similar effect is caused by the presence of different tissue layers (edema or glial tissue in the peri-electrode space. On the contrary, a not accurate positioning of the chronic electrode with respect to the intraoperative one (electric centers not coincident may induce a complete different electric stimulation on some groups of fibers.

  3. Double electrodes simultaneous stimulation and implantation technique in deep brain stimulation

    Institute of Scientific and Technical Information of China (English)

    BIAN Liu-guan; W Tirakotai; DK Schulte; H Bertalanffy; D Hellwig

    2005-01-01

    @@ Posttraumatic tremor is often one of the causes of disability in head injury patients. Usually, pharmacotherapy for this type of tremor is not effective. Since early 1970s, surgical ablation of the ventral thalamus has been used to treat various types of tremor.1 Nowadays, deep brain stimulation (DBS) confirms its efficacy in alleviating different forms of tremor, including posttraumatic tremor.2,3 Such therapy has been reported achieving around 80% success rate in the treatment of posttraumatic tremor.

  4. Evaluation of electrode position in deep brain stimulation by image fusion (MRI and CT)

    Energy Technology Data Exchange (ETDEWEB)

    Barnaure, I.; Lovblad, K.O.; Vargas, M.I. [Geneva University Hospital, Department of Neuroradiology, Geneva 14 (Switzerland); Pollak, P.; Horvath, J.; Boex, C.; Burkhard, P. [Geneva University Hospital, Department of Neurology, Geneva (Switzerland); Momjian, S. [Geneva University Hospital, Department of Neurosurgery, Geneva (Switzerland); Remuinan, J. [Geneva University Hospital, Department of Radiology, Geneva (Switzerland)

    2015-09-15

    Imaging has an essential role in the evaluation of correct positioning of electrodes implanted for deep brain stimulation (DBS). Although MRI offers superior anatomic visualization of target sites, there are safety concerns in patients with implanted material; imaging guidelines are inconsistent and vary. The fusion of postoperative CT with preoperative MRI images can be an alternative for the assessment of electrode positioning. The purpose of this study was to assess the accuracy of measurements realized on fused images (acquired without a stereotactic frame) using a manufacturer-provided software. Data from 23 Parkinson's disease patients who underwent bilateral electrode placement for subthalamic nucleus (STN) DBS were acquired. Preoperative high-resolution T2-weighted sequences at 3 T, and postoperative CT series were fused using a commercially available software. Electrode tip position was measured on the obtained images in three directions (in relation to the midline, the AC-PC line and an AC-PC line orthogonal, respectively) and assessed in relation to measures realized on postoperative 3D T1 images acquired at 1.5 T. Mean differences between measures carried out on fused images and on postoperative MRI lay between 0.17 and 0.97 mm. Fusion of CT and MRI images provides a safe and fast technique for postoperative assessment of electrode position in DBS. (orig.)

  5. Electrical resistance increases at the tissue-electrode interface as an early response to nucleus accumbens deep brain stimulation.

    Science.gov (United States)

    Kale, Rajas P; Kouzani, Abbas Z; Berk, Julian; Walder, Ken; Berk, Michael; Tye, Susannah J; Kale, Rajas P; Kouzani, Abbas Z; Berk, Julian; Walder, Ken; Berk, Michael; Tye, Susannah J; Berk, Julian; Berk, Michael; Tye, Susannah J; Kouzani, Abbas Z; Kale, Rajas P; Walder, Ken

    2016-08-01

    The therapeutic actions of deep brain stimulation are not fully understood. The early inflammatory response of electrode implantation is associated with symptom relief without electrical stimulation, but is negated by anti-inflammatory drugs. Early excitotoxic necrosis and subsequent glial scarring modulate the conductivity of the tissue-electrode interface, which can provide some detail into the inflammatory response of individual patients. The feasibility of this was demonstrated by measuring resistance values across a bipolar electrode which was unilaterally implanted into the nucleus accumbens of a rat while receiving continuous deep brain stimulation with a portable back-mounted device using clinical parameters (130Hz, 200μA, 90μs) for 3 days. Daily resistance values rose significantly (pstimulation.

  6. Model-Based Comparison of Deep Brain Stimulation Array Functionality with Varying Number of Radial Electrodes and Machine Learning Feature Sets.

    Science.gov (United States)

    Teplitzky, Benjamin A; Zitella, Laura M; Xiao, YiZi; Johnson, Matthew D

    2016-01-01

    Deep brain stimulation (DBS) leads with radially distributed electrodes have potential to improve clinical outcomes through more selective targeting of pathways and networks within the brain. However, increasing the number of electrodes on clinical DBS leads by replacing conventional cylindrical shell electrodes with radially distributed electrodes raises practical design and stimulation programming challenges. We used computational modeling to investigate: (1) how the number of radial electrodes impact the ability to steer, shift, and sculpt a region of neural activation (RoA), and (2) which RoA features are best used in combination with machine learning classifiers to predict programming settings to target a particular area near the lead. Stimulation configurations were modeled using 27 lead designs with one to nine radially distributed electrodes. The computational modeling framework consisted of a three-dimensional finite element tissue conductance model in combination with a multi-compartment biophysical axon model. For each lead design, two-dimensional threshold-dependent RoAs were calculated from the computational modeling results. The models showed more radial electrodes enabled finer resolution RoA steering; however, stimulation amplitude, and therefore spatial extent of the RoA, was limited by charge injection and charge storage capacity constraints due to the small electrode surface area for leads with more than four radially distributed electrodes. RoA shifting resolution was improved by the addition of radial electrodes when using uniform multi-cathode stimulation, but non-uniform multi-cathode stimulation produced equivalent or better resolution shifting without increasing the number of radial electrodes. Robust machine learning classification of 15 monopolar stimulation configurations was achieved using as few as three geometric features describing a RoA. The results of this study indicate that, for a clinical-scale DBS lead, more than four radial

  7. Probing the Human Brain with Stimulating Electrodes: The Story of Roberts Bartholow's (1874) Experiment on Mary Rafferty

    Science.gov (United States)

    Harris, Lauren Julius; Almerigi, Jason B.

    2009-01-01

    Roberts Bartholow's 1874 experiment on Mary Rafferty is widely cited as the first demonstration, by direct application of stimulating electrodes, of the motor excitability of the human cerebral cortex. The many accounts of the experiment, however, leave certain questions and details unexamined or unresolved, especially about Bartholow's goals, the…

  8. Neural stimulation and recording electrodes.

    Science.gov (United States)

    Cogan, Stuart F

    2008-01-01

    Electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders. An understanding of the electrochemical mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large numbers of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and maximum electrochemical potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.

  9. Novel fingerprinting method characterises the necessary and sufficient structural connectivity from deep brain stimulation electrodes for a successful outcome

    Science.gov (United States)

    Fernandes, Henrique M.; Van Hartevelt, Tim J.; Boccard, Sandra G. J.; Owen, Sarah L. F.; Cabral, Joana; Deco, Gustavo; Green, Alex L.; Fitzgerald, James J.; Aziz, Tipu Z.; Kringelbach, Morten L.

    2015-01-01

    Deep brain stimulation (DBS) is a remarkably effective clinical tool, used primarily for movement disorders. DBS relies on precise targeting of specific brain regions to rebalance the oscillatory behaviour of whole-brain neural networks. Traditionally, DBS targeting has been based upon animal models (such as MPTP for Parkinson’s disease) but has also been the result of serendipity during human lesional neurosurgery. There are, however, no good animal models of psychiatric disorders such as depression and schizophrenia, and progress in this area has been slow. In this paper, we use advanced tractography combined with whole-brain anatomical parcellation to provide a rational foundation for identifying the connectivity ‘fingerprint’ of existing, successful DBS targets. This knowledge can then be used pre-surgically and even potentially for the discovery of novel targets. First, using data from our recent case series of cingulate DBS for patients with treatment-resistant chronic pain, we demonstrate how to identify the structural ‘fingerprints’ of existing successful and unsuccessful DBS targets in terms of their connectivity to other brain regions, as defined by the whole-brain anatomical parcellation. Second, we use a number of different strategies to identify the successful fingerprints of structural connectivity across four patients with successful outcomes compared with two patients with unsuccessful outcomes. This fingerprinting method can potentially be used pre-surgically to account for a patient’s individual connectivity and identify the best DBS target. Ultimately, our novel fingerprinting method could be combined with advanced whole-brain computational modelling of the spontaneous dynamics arising from the structural changes in disease, to provide new insights and potentially new targets for hitherto impenetrable neuropsychiatric disorders.

  10. Deep brain stimulation

    Science.gov (United States)

    ... a device called a neurostimulator to deliver electrical signals to the areas of the brain that control ... neurostimulator, which puts out the electric current. The stimulator is similar to a heart ...

  11. Probing the human brain with stimulating electrodes: the story of Roberts Bartholow's (1874) experiment on Mary Rafferty.

    Science.gov (United States)

    Harris, Lauren Julius; Almerigi, Jason B

    2009-06-01

    Roberts Bartholow's 1874 experiment on Mary Rafferty is widely cited as the first demonstration, by direct application of stimulating electrodes, of the motor excitability of the human cerebral cortex. The many accounts of the experiment, however, leave certain questions and details unexamined or unresolved, especially about Bartholow's goals, the nature and quality of the evidence, and the experiment's role in the history of theory and research on localisation of function. In this article, we try to fill these gaps and to tell the full story. We describe Bartholow's career up to 1874, review the theoretical and empirical background for the experiment, and present Bartholow's own account of the experiment as well as those of his supporters and critics. We then present our own analysis, assess the experiment's influence on contemporaneous scientific opinion about cortical excitability, and trace its citation record into our own time. We also review and assess ethical criticisms of Bartholow and their effects on his career, and we close by discussing the role we think the experiment deserves to play in the history of theory and research on cortical excitability.

  12. Stimulation and recording electrodes for neural prostheses

    CERN Document Server

    Pour Aryan, Naser; Rothermel, Albrecht

    2015-01-01

    This book provides readers with basic principles of the electrochemistry of the electrodes used in modern, implantable neural prostheses. The authors discuss the boundaries and conditions in which the electrodes continue to function properly for long time spans, which are required when designing neural stimulator devices for long-term in vivo applications. Two kinds of electrode materials, titanium nitride and iridium are discussed extensively, both qualitatively and quantitatively. The influence of the counter electrode on the safety margins and electrode lifetime in a two electrode system is explained. Electrode modeling is handled in a final chapter.

  13. Orientation selective deep brain stimulation

    Science.gov (United States)

    Lehto, Lauri J.; Slopsema, Julia P.; Johnson, Matthew D.; Shatillo, Artem; Teplitzky, Benjamin A.; Utecht, Lynn; Adriany, Gregor; Mangia, Silvia; Sierra, Alejandra; Low, Walter C.; Gröhn, Olli; Michaeli, Shalom

    2017-02-01

    Objective. Target selectivity of deep brain stimulation (DBS) therapy is critical, as the precise locus and pattern of the stimulation dictates the degree to which desired treatment responses are achieved and adverse side effects are avoided. There is a clear clinical need to improve DBS technology beyond currently available stimulation steering and shaping approaches. We introduce orientation selective neural stimulation as a concept to increase the specificity of target selection in DBS. Approach. This concept, which involves orienting the electric field along an axonal pathway, was tested in the corpus callosum of the rat brain by freely controlling the direction of the electric field on a plane using a three-electrode bundle, and monitoring the response of the neurons using functional magnetic resonance imaging (fMRI). Computational models were developed to further analyze axonal excitability for varied electric field orientation. Main results. Our results demonstrated that the strongest fMRI response was observed when the electric field was oriented parallel to the axons, while almost no response was detected with the perpendicular orientation of the electric field relative to the primary fiber tract. These results were confirmed by computational models of the experimental paradigm quantifying the activation of radially distributed axons while varying the primary direction of the electric field. Significance. The described strategies identify a new course for selective neuromodulation paradigms in DBS based on axonal fiber orientation.

  14. Transcranial brain stimulation: closing the loop between brain and stimulation

    DEFF Research Database (Denmark)

    Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

    2016-01-01

    PURPOSE OF REVIEW: To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS: Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain...... transcranial brain stimulation. Priming interventions or paired associative stimulation can be used to ‘standardize’ the brain-state and hereby, homogenize the group response to stimulation. Neuroanatomical and neurochemical profiling based on magnetic resonance imaging and spectroscopy can capture trait......-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified...

  15. Deep Brain Stimulation - the challenges ahead

    NARCIS (Netherlands)

    Heida, T.; Holsheimer, J.; Geelen, J.A.G.; Veltink, P.H.

    2005-01-01

    Parkinson’s disease (PD) is characterized by progressive loss of dopamine neurons in the pars compacta of the substantia nigra, which results in reduced activity in the thalamus. Clinically effective deep brain stimulation (DBS) has been achieved with electrode contacts in the anterior- dorsal subth

  16. Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation

    Science.gov (United States)

    Andrews, Russell J.

    2003-01-01

    Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.

  17. 基于MEMS技术的柔性多触点深部脑刺激电极研制%Design and fabrication of flexible multi- contacts deep brain stimulation electrode based on MEMS technology

    Institute of Scientific and Technical Information of China (English)

    张磊; 李璟文; 周望; 王守岩

    2014-01-01

    深部脑刺激可以有效治疗帕金森病、癫痫、抑郁等疾病。深部脑刺激电极是深部脑刺激系统中的重要组成部分,传统的四触点电极由于通道少,触点面积大,分辨率低,容易刺激不必要的区域从而引起副作用。为提高深部脑刺激的分辨率和精度,设计了一种具有24个触点的深部脑刺激电极,并利用微机电系统制作技术制作出柔性电极。该柔性电极基底材料为生物相容性良好的聚一氯对二甲苯(Parylene C),导电材料为金。电极触点和焊点均为285μm×1500μm ,连接焊点和触点的连接线宽为50μm 。初步电学测试表明,电极具有良好的低阻抗电学性能。使用多触点电极可减小触点尺寸,提高刺激的分辨率,改善脑刺激电极在临床中的治疗效果。%Deep brain stimulation (DBS) is effective for treating some diseases, such as epilepsy, Parkinson's disease or depression. DBS electrode is a key part of a DBS system. The current DBS electrode has four large contacts, and the stimulation resolution is low and the stimulation to unnecessary area of brain tissue may cause side effects. To improve the resolution and precision of the deep brain stimulation, a flexible electrode with multi- contact was designed and produced through a Micro- Electro-Mechanical Systems (MEMS) fabrication method. The new electrode consisted of 24 small contacts. Each electrode contact is 285μm í1 500μm. The micro machining techniques were applied for the electrode fabrication using biocompatible materials Parylene C as the substrate and Au as electrode material respectively. The characteristics of the electrode were physically tested. The electrode has a smooth surface, distinct outline and good electrical properties with low impedance. The MEMS technology is suitable for the deep brain stimulation electrode production. This research would provide a basis for developing better 3- D deep brain stimulation

  18. Brain Stimulation Therapies

    Science.gov (United States)

    ... is preferred by many doctors, patients and families. Vagus Nerve Stimulation Vagus nerve stimulation (VNS) works through a device implanted under ... skin that sends electrical pulses through the left vagus nerve, half of a prominent pair of nerves that ...

  19. Bio-electromagnetic model of deep brain stimulation

    OpenAIRE

    Walckiers, Grégoire

    2009-01-01

    Functional stimulation is one of the most fascinating applications of bioelectromagnetism. It deals with the stimulation of excitable biological tissues by electromagnetic fields. One of its most impressive medical applications is the subthalamic nucleus deep brain stimulation (DBS). It consists in the insertion of an electrode into the deep brain, delivering electric pulses to treat Parkinson's disease and other movement disorders. But despite its wide use throughout the world for almost twe...

  20. Deep Brain Stimulation for Parkinson's Disease

    Science.gov (United States)

    ... You are here Home » Disorders » All Disorders Deep Brain Stimulation for Parkinson's Disease Information Page Deep Brain Stimulation for Parkinson's Disease Information Page Search Disorders ...

  1. Tractography patterns of subthalamic nucleus deep brain stimulation.

    Science.gov (United States)

    Vanegas-Arroyave, Nora; Lauro, Peter M; Huang, Ling; Hallett, Mark; Horovitz, Silvina G; Zaghloul, Kareem A; Lungu, Codrin

    2016-04-01

    Deep brain stimulation therapy is an effective symptomatic treatment for Parkinson's disease, yet the precise mechanisms responsible for its therapeutic effects remain unclear. Although the targets of deep brain stimulation are grey matter structures, axonal modulation is known to play an important role in deep brain stimulation's therapeutic mechanism. Several white matter structures in proximity to the subthalamic nucleus have been implicated in the clinical benefits of deep brain stimulation for Parkinson's disease. We assessed the connectivity patterns that characterize clinically beneficial electrodes in Parkinson's disease patients, after deep brain stimulation of the subthalamic nucleus. We evaluated 22 patients with Parkinson's disease (11 females, age 57 ± 9.1 years, disease duration 13.3 ± 6.3 years) who received bilateral deep brain stimulation of the subthalamic nucleus at the National Institutes of Health. During an initial electrode screening session, one month after deep brain stimulation implantation, the clinical benefits of each contact were determined. The electrode was localized by coregistering preoperative magnetic resonance imaging and postoperative computer tomography images and the volume of tissue activated was estimated from stimulation voltage and impedance. Brain connectivity for the volume of tissue activated of deep brain stimulation contacts was assessed using probabilistic tractography with diffusion-tensor data. Areas most frequently connected to clinically effective contacts included the thalamus, substantia nigra, brainstem and superior frontal gyrus. A series of discriminant analyses demonstrated that the strength of connectivity to the superior frontal gyrus and the thalamus were positively associated with clinical effectiveness. The connectivity patterns observed in our study suggest that the modulation of white matter tracts directed to the superior frontal gyrus and the thalamus is associated with favourable clinical

  2. Magnetic Brain Stimulation in ADHD

    OpenAIRE

    2001-01-01

    Transcranial magnetic brain stimulation was performed in 27 children and adolescents, aged 4 to 18 years, with ADHD in the Services of Pediatric Neurology and Clinical Neurophysiology, Miguel Servet Hospital, Zaragoza, Spain.

  3. Avoiding the ventricle : a simple step to improve accuracy of anatomical targeting during deep brain stimulation

    NARCIS (Netherlands)

    Zrinzo, Ludvic; van Hulzen, Arjen L. J.; Gorgulho, Alessandra A.; Limousin, Patricia; Staal, Michiel J.; De Salles, Antonio A. F.; Hariz, Marwan I.

    2009-01-01

    Object. The authors examined the accuracy of anatomical targeting during electrode implantation for deep brain stimulation in functional neurosurgical procedures. Special attention was focused on the impact that ventricular involvement of the electrode trajectory had on targeting accuracy. Methods.

  4. [Deep brain stimulation for hyperkinetic movement disorders].

    Science.gov (United States)

    Reich, M M; Volkmann, J

    2014-02-01

    The term hyperkinetic movement disorder encompasses dystonia, tremor, chorea, myoclon and tics. These symptoms are all caused by dysfunctional neural networks including the basal ganglia loop and can be accompanied by other neurological or psychiatric symptoms. Deep brain stimulation (DBS) is an important extension of therapeutic options for this group of patients in whom drug therapy is limited. Permanent electrodes are implanted in various subcortical brain areas in order to achieve an improvement in motor symptoms by high frequency stimulation. Already established indications include primary generalized or segmental dystonia and essential tremor but an increasingly better understanding of systemic pathophysiology has allowed DBS to be explored as a treatment for other disorders of the hyperkinetic spectrum. This article provides an overview of common hyperkinetic movement disorders from the viewpoint of recent advances in neurostimulation therapy.

  5. Electroconductive polymer-coated silk fiber electrodes for neural recording and stimulation in vivo

    Science.gov (United States)

    Watanabe, Satoshi; Takahashi, Hideyuki; Torimitsu, Keiichi

    2017-03-01

    We fabricated a silk-based low-impedance flexible electrode by coating a silk thread with the electroconductive polymer poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT:pTS). This electrode had a lower impedance (about 1.8 kΩ/cm) than the silk electrode coated with PEDOT doped with poly(styrene sulfonate) (PEDOT:PSS) (about 1.3 MΩ/cm) reported previously. Using this electrode, a novel gamma-band oscillatory activity was recorded in the electrocorticogram from the embryonic chick brain with a high signal-to-noise ratio. Electrical stimulation was also possible with the silk electrode. We also fabricated an all-silk electrode array and recorded synchronized gamma oscillations. These results demonstrate that the silk electrode can be used for electrophysiological recording and local stimulation in vivo. The silk electrode has the potential to be used for diagnostic and therapeutic purposes and as a brain–machine interface.

  6. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2015-07-01

    Full Text Available Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes.

  7. Technological Advances in Deep Brain Stimulation.

    Science.gov (United States)

    Ughratdar, Ismail; Samuel, Michael; Ashkan, Keyoumars

    2015-01-01

    Functional and stereotactic neurosurgery has always been regarded as a subspecialty based on and driven by technological advances. However until recently, the fundamentals of deep brain stimulation (DBS) hardware and software design had largely remained stagnant since its inception almost three decades ago. Recent improved understanding of disease processes in movement disorders as well clinician and patient demands has resulted in new avenues of development for DBS technology. This review describes new advances both related to hardware and software for neuromodulation. New electrode designs with segmented contacts now enable sophisticated shaping and sculpting of the field of stimulation, potentially allowing multi-target stimulation and avoidance of side effects. To avoid lengthy programming sessions utilising multiple lead contacts, new user-friendly software allows for computational modelling and individualised directed programming. Therapy delivery is being improved with the next generation of smaller profile, longer-lasting, re-chargeable implantable pulse generators (IPGs). These include IPGs capable of delivering constant current stimulation or personalised closed-loop adaptive stimulation. Post-implantation Magnetic Resonance Imaging (MRI) has long been an issue which has been partially overcome with 'MRI conditional devices' and has enabled verification of DBS lead location. Surgical technique is considering a shift from frame-based to frameless stereotaxy or greater role for robot assisted implantation. The challenge for these contemporary techniques however, will be in demonstrating equivalent safety and accuracy to conventional methods. We also discuss potential future direction utilising wireless technology allowing for miniaturisation of hardware.

  8. Deep brain stimulation: postoperative issues.

    Science.gov (United States)

    Deuschl, Günther; Herzog, Jan; Kleiner-Fisman, Galit; Kubu, Cynthia; Lozano, Andres M; Lyons, Kelly E; Rodriguez-Oroz, Maria C; Tamma, Filippo; Tröster, Alexander I; Vitek, Jerrold L; Volkmann, Jens; Voon, Valerie

    2006-06-01

    Numerous factors need to be taken into account when managing a patient with Parkinson's disease (PD) after deep brain stimulation (DBS). Questions such as when to begin programming, how to conduct a programming screen, how to assess the effects of programming, and how to titrate stimulation and medication for each of the targeted sites need to be addressed. Follow-up care should be determined, including patient adjustments of stimulation, timing of follow-up visits and telephone contact with the patient, and stimulation and medication conditions during the follow-up assessments. A management plan for problems that can arise after DBS such as weight gain, dyskinesia, axial symptoms, speech dysfunction, muscle contractions, paresthesia, eyelid, ocular and visual disturbances, and behavioral and cognitive problems should be developed. Long-term complications such as infection or erosion, loss of effect, intermittent stimulation, tolerance, and pain or discomfort can develop and need to be managed. Other factors that need consideration are social and job-related factors, development of dementia, general medical issues, and lifestyle changes. This report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society, outlines answers to a series of questions developed to address all aspects of DBS postoperative management and decision-making with a systematic overview of the literature (until mid-2004) and by the expert opinion of the authors. The report has been endorsed by the Scientific Issues Committee of the Movement Disorder Society and the American Society of Stereotactic and Functional Neurosurgery.

  9. Twiddler's syndrome in a patient with a deep brain stimulation device for generalized dystonia

    DEFF Research Database (Denmark)

    Astradsson, Arnar; Schweder, Patrick M; Joint, Carole

    2011-01-01

    Deep brain stimulation (DBS) is the technique of neurostimulation of deep brain structures for the treatment of conditions such as essential tremor, dystonia, Parkinson's disease and chronic pain syndromes. The procedure uses implanted deep brain stimulation electrodes connected to extension leads...

  10. MRI-induced heating of deep brain stimulation leads

    Energy Technology Data Exchange (ETDEWEB)

    Mohsin, Syed A; Sheikh, Noor M [University of Engineering and Technology, Lahore (Pakistan); Saeed, Usman [Georgia Institute of Technology, Atlanta, GA (United States)], E-mail: syed_alimohsin@uet.edu.pk, E-mail: deanee@uet.edu.pk, E-mail: usaeed@gatech.edu

    2008-10-21

    The radiofrequency (RF) field used in magnetic resonance imaging is scattered by medical implants. The scattered field of a deep brain stimulation lead can be very intense near the electrodes stimulating the brain. The effect is more pronounced if the lead behaves as a resonant antenna. In this paper, we examine the resonant length effect. We also use the finite element method to compute the near field for (i) the lead immersed in inhomogeneous tissue (fat, muscle, and brain tissues) and (ii) the lead connected to an implantable pulse generator. Electric field, specific absorption rate and induced temperature rise distributions have been obtained in the brain tissue surrounding the electrodes. The worst-case scenario has been evaluated by neglecting the effect of blood perfusion. The computed values are in good agreement with in vitro measurements made in the laboratory.

  11. Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of Smart Deep Brain Stimulation

    Science.gov (United States)

    Koehne, Jessica E.

    2016-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable "smart" therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.

  12. Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of "Smart" Deep Brain Stimulation

    Science.gov (United States)

    Koehne, Jessica E.

    2016-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable smart therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.

  13. Nanowire electrodes for high-density stimulation and measurement of neural circuits

    OpenAIRE

    Robinson, Jacob T.; Jorgolli, Marsela; Park, Hongkun

    2013-01-01

    Brain-machine interfaces (BMIs) that can precisely monitor and control neural activity will likely require new hardware with improved resolution and specificity. New nanofabricated electrodes with feature sizes and densities comparable to neural circuits may lead to such improvements. In this perspective, we review the recent development of vertical nanowire (NW) electrodes that could provide highly parallel single-cell recording and stimulation for future BMIs. We compare the advantages of t...

  14. Computer Controlled Switching Device for Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    J. Tauchmanová

    2007-01-01

    Full Text Available This paper has two goals. The practical part deals with the design of a computer controlled switching device for an external stimulator for deep brain stimulation. The switching device is used during investigations with functional magnetic resonance for controlling signals leading to the deep brain stimulation (DBS electrode in the patient's brain. The motivation for designing this device was improve measured data quality and to enable new types of experiments.The theoretical part reports on early attempts to approach the problem of modeling and localizing the neural response of the human brain as a system identification and estimation task. The parametric identification method and real fMRI data are used for modeling the hemodynamic response.The project is in cooperation with 1st Faculty of Medicine, Charles University in Prague and Na Homolce hospital in Prague.

  15. Characterization of electrical stimulation electrodes for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Cannizzaro, Chris; Figallo, Elisa; Voldman, Joel; Vunjak-Novakovic, Gordana

    2006-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. The goal of this study was to assess the conditions of electrical stimulation with respect to the electrode geometry, material properties and charge-transfer characteristics at the electrode-electrolyte interface. We compared various biocompatible materials, including nanoporous carbon, stainless steel, titanium and titanium nitride, for use in cardiac tissue engineering bioreactors. The faradaic and non-faradaic charge transfer mechanisms were assessed by electrochemical impedance spectroscopy (EIS), studying current injection characteristics, and examining surface properties of electrodes with scanning electron microscopy. Carbon electrodes were found to have the best current injection characteristics. However, these electrodes require careful handling because of their limited mechanical strength. The efficacy of various electrodes for use in 2-D and 3-D cardiac tissue engineering systems with neonatal rat cardiomyocytes is being determined by assessing cell viability, amplitude of contractions, excitation thresholds, maximum capture rate, and tissue morphology.

  16. Micro-Reaction Chamber Electrodes for Neural Stimulation and Recording

    OpenAIRE

    Shanmugasundaram, Balaji; Gluckman, Bruce J.

    2011-01-01

    Biocompatible electrodes with smaller geometric area are preferred to improve the selectivity of the neural recording and stimulation applications. We introduce the concept of a micro-reaction chamber (µRC) in which a volume within the electrode back plane is used to confine and sequester the electrochemical reactions used for charge passage. The µRC electrode design helps decrease impedance and improves the charge storage capacity without altering the geometry of the active site. Here we dem...

  17. Transcranial direct current stimulation: electrode montage in stroke.

    Science.gov (United States)

    Mahmoudi, Hooman; Borhani Haghighi, Afshin; Petramfar, Peyman; Jahanshahi, Sepehr; Salehi, Zahra; Fregni, Felipe

    2011-01-01

    Neurophysiological and computer modelling studies have shown that electrode montage is a critical parameter to determine the neuromodulatory effects of transcranial direct current stimulation (tDCS). We tested these results clinically by systematically investigating optimal tDCS electrode montage in stroke. Ten patients received in a counterbalanced and randomised order the following conditions of stimulation (i) anodal stimulation of affected M1 (primary motor cortex) and cathodal stimulation of unaffected M1 ('bilateral tDCS'); (ii) anodal stimulation of affected M1 and cathodal stimulation of contralateral supraorbital area ('anodal tDCS'); (iii) cathodal stimulation of unaffected M1 and anodal stimulation of contralateral supraorbital area ('cathodal tDCS'); (iv) anodal stimulation of affected M1 and cathodal stimulation of contralateral deltoid muscle ('extra-cephalic tDCS') and (v) sham stimulation. We used the Jebsen-Taylor Test (JTT) as a widely accepted measure of upper limb function. Bilateral tDCS, anodal tDCS and cathodal tDCS were shown to be associated with significant improvements on the JTT. Placing the reference electrode in an extracephalic position and use of sham stimulation did not induce any significant effects. This small sham controlled cross-over clinical trial is important to provide additional data on the clinical effects of tDCS in stroke and for planning and designing future large tDCS trials in patients with stroke.

  18. [MRI compatibility of deep brain stimulator].

    Science.gov (United States)

    Zhang, Yujing

    2013-07-01

    Deep brain stimulation (DBS) therapy develops rapidly in clinical application. The structures of deep brain stimulator and magnetic resonance imaging (MRI) equipment are introduced, the interactions are analyzed, and the two compatible problems of radio frequency (RF) heating and imaging artifact are summarized in this paper.

  19. Reinforcing brain stimulation in competition with water reward and shock avoidance.

    Science.gov (United States)

    VALENSTEIN, E S; BEER, B

    1962-09-28

    Employing response rate as the index of reinforcing strength in self-stimulation experiments is questioned. With water reward or shock avoidance placed in competition with brain stimulation, self-stimulation rate does not reflect relative reinforcement value. The results agree with preference tests which show that, for a given electrode site, stimulus intensity, not rate, is directly related to reward strength.

  20. Immediate motor effects of stimulation through electrodes implanted in the human globus pallidus.

    Science.gov (United States)

    Ashby, P; Strafella, A; Dostrovsky, J O; Lozano, A; Lang, A E

    1998-01-01

    The immediate motor effects of stimulation through electrodes chronically implanted in the globus pallidus internus (GPI) were studied in 9 subjects with Parkinson's disease. Single stimuli (at >0.4 Hz) produced short latency facilitation of voluntarily activated contralateral muscles in all subjects. The latency and distribution of the facilitation, its probably monosynaptic nature, and the short chronaxie and refractory period of the activated neural elements suggest that the facilitation results from the direct excitation of the fast conducting corticospinal pathway. The facilitation of motoneurons followed high frequency (e.g. 200 Hz) stimulation without decrement and occurred at stimulus intensities well below those required to produce a visible muscle contraction. We conclude that, while there may be other effects, GPI stimulation through electrodes may activate the corticospinal tract, even when the stimuli are below the threshold for a visible muscle contraction, and that continuous stimulation may do so continuously. This may be an unwanted side effect, but possible therapeutic actions are considered. The reproducible short latency facilitation enabled us to estimate current spread from the quadripolar electrodes used for deep brain stimulation. When the current is sufficient to excite large myelinated fibers near one of the quadripolar electrodes, an additional 1-mA current will activate similar fibers at an additional distance of 1.8 mm with bipolar stimulation and at a distance of 5.7 mm with monopolar stimulation.

  1. Transcranial magnetic stimulation and the human brain

    Science.gov (United States)

    Hallett, Mark

    2000-07-01

    Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.

  2. [Deep brain stimulation and neuroethics].

    Science.gov (United States)

    Katayama, Yoichi; Fukaya, Chikashi

    2009-01-01

    The use of deep brain stimulation (DBS) for mental disorders has been discussed in Japan from the viewpoint of ethical problems. Trials of experimental therapies require a basis of sound scientific rationale. New standard therapy emerges from such trials through detailed analysis of the outcome and side effects. Long-suffering patients with intractable symptoms may desperately seek an experimental therapy even though it has not yet been accepted as standard therapy. The ethical committee of each institution evaluates the level of scientific rationale and the expected level of benefits on the bias of the reported data, and decides whether the patients can receive the experimental therapy. However, the use of DBS for mental disorders is not based on sound scientific rational, since the disease mechanisms involved are far from understood. The data reported from the previous trials are insufficient for assuring the satisfactory results for mental disoder patients. Most institutions in Japan do not accept such levels of scientific rationale and expected benefits. Furthermore, from the cultural perspective, strong skepticism exists in Japan with regard to surgical interventions for mental disorders. Such an attitude is unexpectedly in harmony with many of the subjects currently discussed in the field of neuroethics. For example, who has the right to control DBS? How does someone decide the level of control of mental function by DBS? These questions are related to the discussion on how human society is formed and how the ethics are decided by considering both scientific rationale and human society.

  3. Movement disorders induced by deep brain stimulation.

    Science.gov (United States)

    Baizabal-Carvallo, José Fidel; Jankovic, Joseph

    2016-04-01

    Deep brain stimulation represents a major advance in the treatment of several types of movement disorders. However, during stimulation new movement disorders may emerge, thus limiting the positive effects of this therapy. These movement disorders may be induced by: 1) stimulation of the targeted nucleus, 2) stimulation of surrounding tracts and nuclei, and 3) as a result of dose adjustment of accompanying medications, such as reduction of dopaminergic drugs in patients with Parkinson's disease. Various dyskinesias, blepharospasm, and apraxia of eyelid opening have been described mainly with subthalamic nucleus stimulation, whereas hypokinesia and freezing of gait have been observed with stimulation of the globus pallidus internus. Other deep brain stimulation-related movement disorders include dyskinesias associated with stimulation of the globus pallidus externus and ataxic gait as a side effect of chronic bilateral stimulation of the ventral intermediate nucleus of thalamus. These movement disorders are generally reversible and usually resolved once the stimulation is reduced or turned off. This, however, typically leads to loss of benefit of the underlying movement disorder which can be re-gained by using different contacts, changing targets or stimulation parameters, and adjusting pharmacological therapy. New and innovative emerging technologies and stimulation techniques may help to prevent or overcome the various deep brain stimulation-induced movement disorders. In this review we aim to describe the clinical features, frequency, pathophysiology, and strategies for treatment of these iatrogenic movement disorders.

  4. Stimulation dependent induction of fear and depression in deep brain stimulation: a case report

    Directory of Open Access Journals (Sweden)

    Sabolek Michael

    2009-09-01

    Full Text Available Abstract Introduction Psychiatric side effects of deep brain stimulation are not uncommon. It is often limited to transient mood alterations. We report for the first time a case of acute stimulation-dependent fear during intraoperative test stimulation. Case presentation During test stimulation for electrode placement to the left subthalamic nucleus, a 58-year-old caucasian man with Parkinson's disease developed a severe reproducible feeling of fear together with elevated heart rate and sweating. Postoperatively, the patient developed a therapy refractory major depression in spite of excellent motor-control. Reprogramming the stimulator using a more rostral contact resulted in an abrupt and complete disappearance of the depressive syndrome. Conclusion Postoperative re-evaluation of the stimulation site of the patient inducing acute fear by analyzing his intraoperative microrecordings and Talairach coordinates revealed stimulation within his right substantia nigra. The contrast analysis of the postoperative stimulation site suggests induction of depression in the patient by stimulation of the caudal part of his subthalamic nucleus. Acute psychiatric side effects of deep brain stimulation are relatively rare but must not be overlooked while concentrating on the improvement of motor deficit.

  5. Particle swarm optimization for programming deep brain stimulation arrays

    Science.gov (United States)

    Peña, Edgar; Zhang, Simeng; Deyo, Steve; Xiao, YiZi; Johnson, Matthew D.

    2017-02-01

    Objective. Deep brain stimulation (DBS) therapy relies on both precise neurosurgical targeting and systematic optimization of stimulation settings to achieve beneficial clinical outcomes. One recent advance to improve targeting is the development of DBS arrays (DBSAs) with electrodes segmented both along and around the DBS lead. However, increasing the number of independent electrodes creates the logistical challenge of optimizing stimulation parameters efficiently. Approach. Solving such complex problems with multiple solutions and objectives is well known to occur in biology, in which complex collective behaviors emerge out of swarms of individual organisms engaged in learning through social interactions. Here, we developed a particle swarm optimization (PSO) algorithm to program DBSAs using a swarm of individual particles representing electrode configurations and stimulation amplitudes. Using a finite element model of motor thalamic DBS, we demonstrate how the PSO algorithm can efficiently optimize a multi-objective function that maximizes predictions of axonal activation in regions of interest (ROI, cerebellar-receiving area of motor thalamus), minimizes predictions of axonal activation in regions of avoidance (ROA, somatosensory thalamus), and minimizes power consumption. Main results. The algorithm solved the multi-objective problem by producing a Pareto front. ROI and ROA activation predictions were consistent across swarms (multi-compartment axon model simulations showed discrepancies of  program DBS systems especially those with higher electrode counts.

  6. Sputtered iridium oxide films (SIROFs) for neural stimulation electrodes

    OpenAIRE

    Cogan, Stuart F.; Ehrlich, Julia; Plante, Timothy D.; Smirnov, Anton; Shire, Douglas B.; Gingerich, Marcus; Rizzo, Joseph F

    2004-01-01

    Sputtered iridium oxide films (SIROFs) deposited by DC reactive sputtering from an iridium metal target have been characterized in vitro for their potential as neural recording and stimulation electrodes. SIROFs were deposited over gold metallization on flexible multielectrode arrays fabricated on thin (15 µm) polyimide substrates. SIROF thickness and electrode areas of 200–1300 nm and 1960–125600 µm2, respectively, were investigated. The charge-injection capacities of the SIROFs were evaluat...

  7. Functional electrical stimulation with surface electrodes

    Directory of Open Access Journals (Sweden)

    Bajd Tadej

    2008-01-01

    Full Text Available The review investigates the objective evidences of benefits derived from surface functional electrical stimulation (FES of lower and upper extremities for people after incomplete spinal cord injury (SCI and stroke. FES can offer noticeable benefits in walking ability. It can be efficiently combined with treadmill and body weight support. Voluntary muscle strength and endurance gain can be achieved through FES assisted gait training together with increased gait velocity in absence of electrical stimulator. Cyclic FES, FES augmented by biofeedback, and FES used in various daily activities can result in substantial improvements of the voluntary control of upper extremities.

  8. Brain stimulation for intractable epilepsy: Anterior thalamus and responsive stimulation

    Directory of Open Access Journals (Sweden)

    Vibhor Krishna

    2014-01-01

    Full Text Available Despite medications, resective surgery, and vagal nerve stimulation, some patients with epilepsy continue to have seizures. In these patients, other approaches are urgently needed. The biological basis of stimulation of anterior thalamic nucleus and epileptogenic focus is presented. Results from two large randomized controlled trials Stimulation of Anterior Nucleus of Thalamus for Epilepsy (SANTE and Neuropace pivotal trial are discussed. Neuromodulation provides effective treatment for a select group of refractory epilepsy patients. Future investigations into the mechanism underlying ′response′ to brain stimulation are desired.

  9. Brain stimulation in posttraumatic stress disorder.

    Science.gov (United States)

    Novakovic, Vladan; Sher, Leo; Lapidus, Kyle A B; Mindes, Janet; A Golier, Julia; Yehuda, Rachel

    2011-01-01

    Posttraumatic stress disorder (PTSD) is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT) and Cranial electrotherapy stimulation (CES) have both been in use for decades; transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), deep brain stimulation (DBS), transcranial Direct Current Stimulation (tDCS), and vagus nerve stimulation (VNS) have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES), depression (ECT, CES, rTMS, VNS, DBS), obsessive-compulsive disorder (OCD) (DBS), essential tremor, dystonia (DBS), epilepsy (DBS, VNS), Parkinson Disease (DBS), pain (CES), and insomnia (CES). To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in

  10. Combined use of transcranial magnetic stimulation and metal electrode implants: a theoretical assessment of safety considerations

    Science.gov (United States)

    Golestanirad, Laleh; Rouhani, Hossein; Elahi, Behzad; Shahim, Kamal; Chen, Robert; Mosig, Juan R.; Pollo, Claudio; Graham, Simon J.

    2012-12-01

    This paper provides a theoretical assessment of the safety considerations encountered in the simultaneous use of transcranial magnetic stimulation (TMS) and neurological interventions involving implanted metallic electrodes, such as electrocorticography. Metal implants are subject to magnetic forces due to fast alternating magnetic fields produced by the TMS coil. The question of whether the mechanical movement of the implants leads to irreversible damage of brain tissue is addressed by an electromagnetic simulation which quantifies the magnitude of imposed magnetic forces. The assessment is followed by a careful mechanical analysis determining the maximum tolerable force which does not cause irreversible tissue damage. Results of this investigation provide useful information on the range of TMS stimulator output powers which can be safely used in patients having metallic implants. It is shown that conventional TMS applications can be considered safe when applied on patients with typical electrode implants as the induced stress in the brain tissue remains well below the limit of tissue damage.

  11. Anaesthetic management of a patient with deep brain stimulation implant for radical nephrectomy

    Directory of Open Access Journals (Sweden)

    Monica Khetarpal

    2014-01-01

    Full Text Available A 63-year-old man with severe Parkinson′s disease (PD who had been implanted with deep brain stimulators into both sides underwent radical nephrectomy under general anaesthesia with standard monitoring. Deep brain stimulation (DBS is an alternative and effective treatment option for severe and refractory PD and other illnesses such as essential tremor and intractable epilepsy. Anaesthesia in the patients with implanted neurostimulator requires special consideration because of the interaction between neurostimulator and the diathermy. The diathermy can damage the brain tissue at the site of electrode. There are no standard guidelines for the anaesthetic management of a patient with DBS electrode in situ posted for surgery.

  12. Eyelid apraxia associated with deep brain stimulation of the periaqueductal gray area.

    Science.gov (United States)

    Langevin, Jean-Philippe; Srikandarajah, Nisaharan; Krahl, Scott E; Gorgulho, Alessandra; Behnke, Eric; Malkasian, Dennis; DeSalles, Antonio A F

    2014-09-01

    We report a patient with eyelid apraxia following deep brain stimulation of the periaqueductal gray area. Based on the position of our electrode, we argue that the phenomenon is linked to inhibition of the nearby central caudal nucleus of the oculomotor nucleus by high frequency stimulation.

  13. Best of both worlds: promise of combining brain stimulation and brain connectome

    OpenAIRE

    Caroline Di Bernardi Luft; Ernesto ePereda; Michael eBanissy; Joydeep eBhattacharya

    2014-01-01

    Transcranial current brain stimulation (tCS) is becoming increasingly popular as a non-pharmacological non-invasive neuromodulatory method that alters cortical excitability by applying weak electrical currents to the scalp via a pair of electrodes. Most applications of this technique have focused on enhancing motor and learning skills, as well as a therapeutic agent in neurological and psychiatric disorders. In these applications, similarly to lesion studies, tCS was used to provide a causal ...

  14. Perceptual Interactions Between Electrodes Using Focused and Monopolar Cochlear Stimulation

    DEFF Research Database (Denmark)

    Marozeau, Jeremy; McDermott, Hugh J.; Swanson, Brett A.;

    2015-01-01

    to implement an all-polar (AP) stimulation mode designed to create a focused electrical field. The goal of this experiment was to study the potential benefits of this all-polar mode for reducing uncontrolled electrode interactions compared with the monopolar mode. The five participants who took part......-matched sequential and simultaneous stimuli composed of 2 spatially separated pulse trains was measured as function of the electrode separation. Results indicated a strong current-summation interaction for simultaneous stimuli in the MP mode for separations up to at least 4.8 mm. No significant interaction was found...

  15. Brain Tissue Oxygen: In Vivo Monitoring with Carbon Paste Electrodes

    Directory of Open Access Journals (Sweden)

    John P. Lowry

    2005-11-01

    Full Text Available In this communication we review selected experiments involving the use ofcarbon paste electrodes (CPEs to monitor and measure brain tissue O2 levels in awakefreely-moving animals. Simultaneous measurements of rCBF were performed using the H2clearance technique. Voltammetric techniques used include both differential pulse (O2 andconstant potential amperometry (rCBF. Mild hypoxia and hyperoxia produced rapidchanges (decrease and increase respectively in the in vivo O2 signal. Neuronal activation(tail pinch and stimulated grooming produced similar increases in both O2 and rCBFindicating that CPE O2 currents provide an index of increases in rCBF when such increasesexceed O2 utilization. Saline injection produced a transient increase in the O2 signal whilechloral hydrate produced slower more long-lasting changes that accompanied the behavioralchanges associated with anaesthesia. Acetazolamide increased O2 levels through an increasein rCBF.

  16. What is the optimal anodal electrode position for inducing corticomotor excitability changes in transcranial direct current stimulation?

    Science.gov (United States)

    Lee, Minji; Kim, Yun-Hee; Im, Chang-Hwan; Kim, Jung-Hoon; Park, Chang-hyun; Chang, Won Hyuk; Lee, Ahee

    2015-01-01

    Transcranial direct current stimulation (tDCS) non-invasively modulates brain function by inducing neuronal excitability. The conventional hot spot for inducing the highest current density in the hand motor area may not be the optimal site for effective stimulation. In this study, we investigated the influence of the center position of the anodal electrode on changes in motor cortical excitability. We considered three tDCS conditions in 16 healthy subjects: (i) real stimulation with the anodal electrode located at the conventional hand motor hot spot determined by motor evoked potentials (MEPs); (ii) real stimulation with the anodal electrode located at the point with the highest current density in the hand motor area as determined by electric current simulation; and (iii) sham stimulation. Motor cortical excitability as measured by MEP amplitude increased after both real stimulation conditions, but not after sham stimulation. Stimulation using the simulation-derived anodal electrode position, which was found to be posterior to the MEP hot spot for all subjects, induced higher motor cortical excitability. Individual positioning of the anodal electrode, based on the consideration of anatomical differences between subjects, appears to be important for maximizing the effects of tDCS.

  17. Deep brain stimulation for cluster headache

    DEFF Research Database (Denmark)

    Grover, Patrick J; Pereira, Erlick A C; Green, Alexander L

    2009-01-01

    Cluster headache is a severely debilitating disorder that can remain unrelieved by current pharmacotherapy. Alongside ablative neurosurgical procedures, neuromodulatory treatments of deep brain stimulation (DBS) and occipital nerve simulation have emerged in the last few years as effective...... circumstances to intervene. Here we review current data on neurosurgical interventions for chronic cluster headache focusing upon DBS and occipital nerve stimulation, and discuss the indications for and putative mechanisms of DBS including translational insights from functional neuroimaging, diffusion weighted...

  18. Brain stimulation for treatment of refractory epilepsy

    Institute of Scientific and Technical Information of China (English)

    GE Yan; HU Wei; LIU Chong; ZHANG Jian-guo; MENG Fan-gang

    2013-01-01

    Objective We review the targets of the deep brain and the responsive neurostimulation system (RNS) to identify the best optimal stimulation parameters and the best mode of stimulation,whether cyclical,continuous,or smarter.Data sources This review is based on data obtained from published articles from 1950 to 2013.To perform the PubMed literature search,the following keywords were input:deep brain stimulation (DBS),RNS,and refractory epilepsy.Study selection Articles containing information related to brain stimulation or RNS for the treatment of refractory epilepsy were selected.Results The currently available treatment options for those patients who resist multiple antiepileptic medications and surgical procedures include electric stimulation,both direct and indirect,of brain nuclei thought to be involved in epileptogenesis.The number of potential targets has increased over the years to include the anterior nucleus of the thalamus,the centromedian nucleus of the thalamus,the hippocampus,the subthalamic nucleus,the caudate nucleus,and the cerebellum,among others.The results of a randomized controlled trial and the RNS trial were published to reveal the effectiveness.Conclusions Although statistically significant reductions in seizures have been observed using several different stimulation techniques,including vagus nerve stimulation,DBS,and RNS,these effects are currently only palliative and do not approach the efficacy comparable with that seen in resection in appropriately selected patients.More research is needed to determine optimal stimulation targets and techniques as well as to determine which epilepsy patients will benefit most from this technology.

  19. Brain stimulation in posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Vladan Novakovic

    2011-10-01

    Full Text Available Posttraumatic stress disorder (PTSD is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT and Cranial electrotherapy stimulation (CES have both been in use for decades; transcranial magnetic stimulation (TMS, magnetic seizure therapy (MST, deep brain stimulation (DBS, transcranial Direct Current Stimulation (tDCS, and vagus nerve stimulation (VNS have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES, depression (ECT, CES, rTMS, VNS, DBS, obsessive-compulsive disorder (OCD (DBS, essential tremor, dystonia (DBS, epilepsy (DBS, VNS, Parkinson Disease (DBS, pain (CES, and insomnia (CES. To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in

  20. Implantable optical-electrode device for stimulation of spinal motoneurons

    Science.gov (United States)

    Matveev, M. V.; Erofeev, A. I.; Zakharova, O. A.; Pyatyshev, E. N.; Kazakin, A. N.; Vlasova, O. L.

    2016-08-01

    Recent years, optogenetic method of scientific research has proved its effectiveness in the nerve cell stimulation tasks. In our article we demonstrate an implanted device for the spinal optogenetic motoneurons activation. This work is carried out in the Laboratory of Molecular Neurodegeneration of the Peter the Great St. Petersburg Polytechnic University, together with Nano and Microsystem Technology Laboratory. The work of the developed device is based on the principle of combining fiber optic light stimulation of genetically modified cells with the microelectrode multichannel recording of neurons biopotentials. The paper presents a part of the electrode implant manufacturing technique, combined with the optical waveguide of ThorLabs (USA).

  1. Ethical issues in deep brain stimulation

    NARCIS (Netherlands)

    M.H.N. Schermer (Maartje)

    2011-01-01

    textabstractDeep brain stimulation (DBS) is currently used to treat neurological disorders like Parkinson's disease, essential tremor, and dystonia, and is explored as an experimental treatment for psychiatric disorders like major depression and obsessive compulsive disorder. This mini review discus

  2. Electrodeposited iridium oxide for neural stimulation and recording electrodes.

    Science.gov (United States)

    Meyer, R D; Cogan, S F; Nguyen, T H; Rauh, R D

    2001-03-01

    Iridium oxide films formed by electrodeposition onto noniridium metal substrates are compared with activated iridium oxide films (AIROFs) as a low impedance, high charge capacity coating for neural stimulation and recording electrodes. The electrodeposited iridium oxide films (EIROFs) were deposited on Au, Pt, PtIr, and 316 LVM stainless steel substrates from a solution of IrCl4, oxalic acid, and K2CO3. A deposition protocol involving 50 potential sweeps at 50 mV/s between limits of 0.0 V and 0.55 V (versus Ag AgCl) followed by potential pulsing between the same limits produced adherent films with a charge storage capacity of >25 mC/cm2. Characterization by cyclic voltammetry and impedance spectroscopy revealed no differences in the electrochemical behavior of EIROF on non-Ir substrates and AIROF. The mechanical stability of the oxides was evaluated by ultrasonication in distilled water followed by dehydration and rehydration. Stability under charge injection was evaluated using 200 micros, 5.9 A/cm2 (1.2 mC/cm2) cathodal pulses. Loss of iridium oxide charge capacity was comparable for AIROFs and the EIROFs, ranging from 1% to 8% of the capacity immediately after activation or deposition. The EIROFs were deposited and evaluated on silicon microprobe electrodes and on metallized polyimide electrodes being developed for neural recording and stimulation applications.

  3. Ultra-nanocrystalline diamond electrodes: optimization towards neural stimulation applications.

    Science.gov (United States)

    Garrett, David J; Ganesan, Kumaravelu; Stacey, Alastair; Fox, Kate; Meffin, Hamish; Prawer, Steven

    2012-02-01

    Diamond is well known to possess many favourable qualities for implantation into living tissue including biocompatibility, biostability, and for some applications hardness. However, conducting diamond has not, to date, been exploited in neural stimulation electrodes due to very low electrochemical double layer capacitance values that have been previously reported. Here we present electrochemical characterization of ultra-nanocrystalline diamond electrodes grown in the presence of nitrogen (N-UNCD) that exhibit charge injection capacity values as high as 163 µC cm(-2) indicating that N-UNCD is a viable material for microelectrode fabrication. Furthermore, we show that the maximum charge injection of N-UNCD can be increased by tailoring growth conditions and by subsequent electrochemical activation. For applications requiring yet higher charge injection, we show that N-UNCD electrodes can be readily metalized with platinum or iridium, further increasing charge injection capacity. Using such materials an implantable neural stimulation device fabricated from a single piece of bio-permanent material becomes feasible. This has significant advantages in terms of the physical stability and hermeticity of a long-term bionic implant.

  4. Wireless fast-scan cyclic voltammetry to monitor adenosine in patients with essential tremor during deep brain stimulation.

    Science.gov (United States)

    Chang, Su-Youne; Kim, Inyong; Marsh, Michael P; Jang, Dong Pyo; Hwang, Sun-Chul; Van Gompel, Jamie J; Goerss, Stephan J; Kimble, Christopher J; Bennet, Kevin E; Garris, Paul A; Blaha, Charles D; Lee, Kendall H

    2012-08-01

    Essential tremor is often markedly reduced during deep brain stimulation simply by implanting the stimulating electrode before activating neurostimulation. Referred to as the microthalamotomy effect, the mechanisms of this unexpected consequence are thought to be related to microlesioning targeted brain tissue, that is, a microscopic version of tissue ablation in thalamotomy. An alternate possibility is that implanting the electrode induces immediate neurochemical release. Herein, we report the experiment performing with real-time fast-scan cyclic voltammetry to quantify neurotransmitter concentrations in human subjects with essential tremor during deep brain stimulation. The results show that the microthalamotomy effect is accompanied by local neurochemical changes, including adenosine release.

  5. Neuroethics of deep brain stimulation for mental disorders: brain stimulation reward in humans.

    Science.gov (United States)

    Oshima, Hideki; Katayama, Yoichi

    2010-01-01

    The theoretical basis of some deep brain stimulation (DBS) trials undertaken in the early years was the phenomenon of "brain stimulation reward (BSR)," which was first identified in rats. The animals appeared to be rewarded by pleasure caused by the stimulation of certain brain regions (reward system), such as the septal area. "Self-stimulation" experiments, in which rats were allowed to stimulate their own brain by pressing a freely accessible lever, they quickly learned lever pressing and sometimes continued to stimulate until they exhausted themselves. BSR was also observed with DBS of the septal area in humans. DBS trials in later years were undertaken on other theoretical bases, but unexpected BSR was sometimes induced by stimulation of some areas, such as the locus coeruleus complex. When BSR was induced, the subjects experienced feelings that were described as "cheerful," "alert," "good," "well-being," "comfort," "relaxation," "joy," or "satisfaction." Since the DBS procedure is equivalent to a "self-stimulation" experiment, they could become "addicted to the stimulation itself" or "compulsive about the stimulation," and stimulate themselves "for the entire day," "at maximum amplitude" and, in some instances, "into convulsions." DBS of the reward system has recently been applied to alleviate anhedonia in patients with refractory major depression. Although this approach appears promising, there remains a difficult problem: who can adjust their feelings and reward-oriented behavior within the normal range? With a self-stimulation procedure, the BSR may become uncontrollable. To develop DBS to the level of a standard therapy for mental disorders, we need to discuss "Who has the right to control the mental condition?" and "Who makes decisions" on "How much control is appropriate?" in daily life.

  6. Brain networks modulated by subthalamic nucleus deep brain stimulation.

    Science.gov (United States)

    Accolla, Ettore A; Herrojo Ruiz, Maria; Horn, Andreas; Schneider, Gerd-Helge; Schmitz-Hübsch, Tanja; Draganski, Bogdan; Kühn, Andrea A

    2016-09-01

    Deep brain stimulation of the subthalamic nucleus is an established treatment for the motor symptoms of Parkinson's disease. Given the frequent occurrence of stimulation-induced affective and cognitive adverse effects, a better understanding about the role of the subthalamic nucleus in non-motor functions is needed. The main goal of this study is to characterize anatomical circuits modulated by subthalamic deep brain stimulation, and infer about the inner organization of the nucleus in terms of motor and non-motor areas. Given its small size and anatomical intersubject variability, functional organization of the subthalamic nucleus is difficult to investigate in vivo with current methods. Here, we used local field potential recordings obtained from 10 patients with Parkinson's disease to identify a subthalamic area with an analogous electrophysiological signature, namely a predominant beta oscillatory activity. The spatial accuracy was improved by identifying a single contact per macroelectrode for its vicinity to the electrophysiological source of the beta oscillation. We then conducted whole brain probabilistic tractography seeding from the previously identified contacts, and further described connectivity modifications along the macroelectrode's main axis. The designated subthalamic 'beta' area projected predominantly to motor and premotor cortical regions additional to connections to limbic and associative areas. More ventral subthalamic areas showed predominant connectivity to medial temporal regions including amygdala and hippocampus. We interpret our findings as evidence for the convergence of different functional circuits within subthalamic nucleus' portions deemed to be appropriate as deep brain stimulation target to treat motor symptoms in Parkinson's disease. Potential clinical implications of our study are illustrated by an index case where deep brain stimulation of estimated predominant non-motor subthalamic nucleus induced hypomanic behaviour.

  7. A method for direct thalamic stimulation in fMRI studies using a glass-coated carbon fiber electrode.

    Science.gov (United States)

    Shyu, Bai-Chuang; Lin, Chun-Yu; Sun, Jyh-Jang; Sylantyev, Sergiy; Chang, Chen

    2004-08-15

    Recent fMRI studies are of interest in exploring long-range interactions between different brain structures and the functional activation of specific brain regions by known neuroanatomical pathways. One of the experimental approaches requires the invasive implantation of an intracranial electrode to excite specific brain structures. In the present report, we describe a procedure for the production of a glass-coated carbon fiber electrode and the use of this electrode for direct activation of the brain in fMRI studies. The glass-coated carbon fiber microelectrode was implanted in the medial thalamus of anaesthetized rats and T2*-weighted gradient echo images in the sagittal plane obtained on a 4.7 T system (Biospec BMT 47/40) during electrical stimulation of the medial thalamus. The image quality obtained using this electrode was acceptable without reduction of the signal-to-noise ratio and image distortion. Cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral anterior cingulate cortex were significantly increased by about 4-5% during medial thalamus stimulation. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocingulate activation.

  8. Optogenetics and deep brain stimulation neurotechnologies.

    Science.gov (United States)

    Kondabolu, Krishnakanth; Kowalski, Marek Mateusz; Roberts, Erik Andrew; Han, Xue

    2015-01-01

    Brain neural network is composed of densely packed, intricately wired neurons whose activity patterns ultimately give rise to every behavior, thought, or emotion that we experience. Over the past decade, a novel neurotechnique, optogenetics that combines light and genetic methods to control or monitor neural activity patterns, has proven to be revolutionary in understanding the functional role of specific neural circuits. We here briefly describe recent advance in optogenetics and compare optogenetics with deep brain stimulation technology that holds the promise for treating many neurological and psychiatric disorders.

  9. Electrodes for high-definition transcutaneous DC stimulation for applications in drug delivery and electrotherapy, including tDCS.

    Science.gov (United States)

    Minhas, Preet; Bansal, Varun; Patel, Jinal; Ho, Johnson S; Diaz, Julian; Datta, Abhishek; Bikson, Marom

    2010-07-15

    Transcutaneous electrical stimulation is applied in a range of biomedical applications including transcranial direct current stimulation (tDCS). tDCS is a non-invasive procedure where a weak direct current (<2 mA) is applied across the scalp to modulate brain function. High-definition tDCS (HD-tDCS) is a technique used to increase the spatial focality of tDCS by passing current across the scalp using <12 mm diameter electrodes. The purpose of this study was to design and optimize "high-definition" electrode-gel parameters for electrode durability, skin safety and subjective pain. Anode and cathode electrode potential, temperature, pH and subjective sensation over time were assessed during application of 2 mA direct current, for up to 22 min on agar gel or subject forearms. A selection of five types of solid-conductors (Ag pellet, Ag/AgCl pellet, rubber pellet, Ag/AgCl ring and Ag/AgCl disc) and seven conductive gels (Signa, Spectra, Tensive, Redux, BioGel, Lectron and CCNY-4) were investigated. The Ag/AgCl ring in combination with CCNY-4 gel resulted in the most favorable outcomes. Under anode stimulations, electrode potential and temperature rises were generally observed in all electrode-gel combinations except for Ag/AgCl ring and disc electrodes. pH remained constant for all solid-conductors except for both Ag and rubber pellet electrodes with Signa and CCNY-4 gels. Sensation ratings were independent of stimulation polarity. Ag/AgCl ring electrodes were found to be the most comfortable followed by Ag, rubber and Ag/AgCl pellet electrodes across all gels.

  10. A diamond-based electrode for detection of neurochemicals in the human brain

    Directory of Open Access Journals (Sweden)

    Kevin E. Bennet

    2016-03-01

    Full Text Available Deep brain stimulation (DBS, a surgical technique to treat certain neurologic and psychiatric conditions, relies on pre-determined stimulation parameters in an open-loop configuration. The major advancement in DBS devices is a closed-loop system that uses neurophysiologic feedback to dynamically adjust stimulation frequency and amplitude. Stimulation-driven neurochemical release can be measured by fast-scan cyclic voltammetry (FSCV, but existing FSCV electrodes rely on carbon fiber, which degrades quickly during use and is therefore unsuitable for chronic neurochemical recording. To address this issue, we developed durable, synthetic boron-doped diamond-based electrodes capable of measuring neurochemical release in humans. Compared to carbon fiber electrodes, they were more than two orders-of-magnitude more physically-robust and demonstrated longevity in vitro without deterioration. Applied for the first time in humans, diamond electrode recordings from thalamic targets in patients (n=4 undergoing DBS for tremor produced signals consistent with adenosine release at a sensitivity comparable to carbon fiber electrodes.

  11. Deep Brain Stimulation og Identitet i Fremtiden

    OpenAIRE

    Andersen, Camilla; Farah, Adna; Pil, Kierkegaard; Lucas, Haasum

    2015-01-01

    The rapidly progressing technology of today is the impetus for increased interest and discussion regarding transhumanism. As a result, our group has decided to conduct research regarding deep brain stimulation, in order to focus on a single technology that is growing rapidly and seeing multiple uses in treating various neurological pathologies. The possibilities of the technology will be relevant to the future of transhuman though, as well as the immediate effects on the individuals who elec...

  12. Mapping entrained brain oscillations during transcranial alternating current stimulation (tACS).

    Science.gov (United States)

    Witkowski, Matthias; Garcia-Cossio, Eliana; Chander, Bankim S; Braun, Christoph; Birbaumer, Niels; Robinson, Stephen E; Soekadar, Surjo R

    2016-10-15

    Transcranial alternating current stimulation (tACS), a non-invasive and well-tolerated form of electric brain stimulation, can influence perception, memory, as well as motor and cognitive function. While the exact underlying neurophysiological mechanisms are unknown, the effects of tACS are mainly attributed to frequency-specific entrainment of endogenous brain oscillations in brain areas close to the stimulation electrodes, and modulation of spike timing dependent plasticity reflected in gamma band oscillatory responses. tACS-related electromagnetic stimulator artifacts, however, impede investigation of these neurophysiological mechanisms. Here we introduce a novel approach combining amplitude-modulated tACS during whole-head magnetoencephalography (MEG) allowing for artifact-free source reconstruction and precise mapping of entrained brain oscillations underneath the stimulator electrodes. Using this approach, we show that reliable reconstruction of neuromagnetic low- and high-frequency oscillations including high gamma band activity in stimulated cortical areas is feasible opening a new window to unveil the mechanisms underlying the effects of stimulation protocols that entrain brain oscillatory activity.

  13. Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function.

    Science.gov (United States)

    Curado, Marco; Fritsch, Brita; Reis, Janine

    2016-02-04

    Non-invasive electrical brain stimulation (NEBS) is used to modulate brain function and behavior, both for research and clinical purposes. In particular, NEBS can be applied transcranially either as direct current stimulation (tDCS) or alternating current stimulation (tACS). These stimulation types exert time-, dose- and in the case of tDCS polarity-specific effects on motor function and skill learning in healthy subjects. Lately, tDCS has been used to augment the therapy of motor disabilities in patients with stroke or movement disorders. This article provides a step-by-step protocol for targeting the primary motor cortex with tDCS and transcranial random noise stimulation (tRNS), a specific form of tACS using an electrical current applied randomly within a pre-defined frequency range. The setup of two different stimulation montages is explained. In both montages the emitting electrode (the anode for tDCS) is placed on the primary motor cortex of interest. For unilateral motor cortex stimulation the receiving electrode is placed on the contralateral forehead while for bilateral motor cortex stimulation the receiving electrode is placed on the opposite primary motor cortex. The advantages and disadvantages of each montage for the modulation of cortical excitability and motor function including learning are discussed, as well as safety, tolerability and blinding aspects.

  14. Deep Brain Electrical Stimulation in Epilepsy

    Science.gov (United States)

    Rocha, Luisa L.

    2008-11-01

    The deep brain electrical stimulation has been used for the treatment of neurological disorders such as Parkinson's disease, chronic pain, depression and epilepsy. Studies carried out in human brain indicate that the application of high frequency electrical stimulation (HFS) at 130 Hz in limbic structures of patients with intractable temporal lobe epilepsy abolished clinical seizures and significantly decreased the number of interictal spikes at focus. The anticonvulsant effects of HFS seem to be more effective in patients with less severe epilepsy, an effect associated with a high GABA tissue content and a low rate of cell loss. In addition, experiments using models of epilepsy indicate that HFS (pulses of 60 μs width at 130 Hz at subthreshold current intensity) of specific brain areas avoids the acquisition of generalized seizures and enhances the postictal seizure suppression. HFS is also able to modify the status epilepticus. It is concluded that the effects of HFS may be a good strategy to reduce or avoid the epileptic activity.

  15. Computational modeling of pedunculopontine nucleus deep brain stimulation

    Science.gov (United States)

    Zitella, Laura M.; Mohsenian, Kevin; Pahwa, Mrinal; Gloeckner, Cory; Johnson, Matthew D.

    2013-08-01

    Objective. Deep brain stimulation (DBS) near the pedunculopontine nucleus (PPN) has been posited to improve medication-intractable gait and balance problems in patients with Parkinson's disease. However, clinical studies evaluating this DBS target have not demonstrated consistent therapeutic effects, with several studies reporting the emergence of paresthesia and oculomotor side effects. The spatial and pathway-specific extent to which brainstem regions are modulated during PPN-DBS is not well understood. Approach. Here, we describe two computational models that estimate the direct effects of DBS in the PPN region for human and translational non-human primate (NHP) studies. The three-dimensional models were constructed from segmented histological images from each species, multi-compartment neuron models and inhomogeneous finite element models of the voltage distribution in the brainstem during DBS. Main Results. The computational models predicted that: (1) the majority of PPN neurons are activated with -3 V monopolar cathodic stimulation; (2) surgical targeting errors of as little as 1 mm in both species decrement activation selectivity; (3) specifically, monopolar stimulation in caudal, medial, or anterior PPN activates a significant proportion of the superior cerebellar peduncle (up to 60% in the human model and 90% in the NHP model at -3 V) (4) monopolar stimulation in rostral, lateral or anterior PPN activates a large percentage of medial lemniscus fibers (up to 33% in the human model and 40% in the NHP model at -3 V) and (5) the current clinical cylindrical electrode design is suboptimal for isolating the modulatory effects to PPN neurons. Significance. We show that a DBS lead design with radially-segmented electrodes may yield improved functional outcome for PPN-DBS.

  16. Optimization of focality and direction in dense electrode array transcranial direct current stimulation (tDCS)

    Science.gov (United States)

    Guler, Seyhmus; Dannhauer, Moritz; Erem, Burak; Macleod, Rob; Tucker, Don; Turovets, Sergei; Luu, Phan; Erdogmus, Deniz; Brooks, Dana H.

    2016-06-01

    Objective. Transcranial direct current stimulation (tDCS) aims to alter brain function non-invasively via electrodes placed on the scalp. Conventional tDCS uses two relatively large patch electrodes to deliver electrical current to the brain region of interest (ROI). Recent studies have shown that using dense arrays containing up to 512 smaller electrodes may increase the precision of targeting ROIs. However, this creates a need for methods to determine effective and safe stimulus patterns as the number of degrees of freedom is much higher with such arrays. Several approaches to this problem have appeared in the literature. In this paper, we describe a new method for calculating optimal electrode stimulus patterns for targeted and directional modulation in dense array tDCS which differs in some important aspects with methods reported to date. Approach. We optimize stimulus pattern of dense arrays with fixed electrode placement to maximize the current density in a particular direction in the ROI. We impose a flexible set of safety constraints on the current power in the brain, individual electrode currents, and total injected current, to protect subject safety. The proposed optimization problem is convex and thus efficiently solved using existing optimization software to find unique and globally optimal electrode stimulus patterns. Main results. Solutions for four anatomical ROIs based on a realistic head model are shown as exemplary results. To illustrate the differences between our approach and previously introduced methods, we compare our method with two of the other leading methods in the literature. We also report on extensive simulations that show the effect of the values chosen for each proposed safety constraint bound on the optimized stimulus patterns. Significance. The proposed optimization approach employs volume based ROIs, easily adapts to different sets of safety constraints, and takes negligible time to compute. An in-depth comparison study gives

  17. Acupuncture stimulation induces neurogenesis in adult brain.

    Science.gov (United States)

    Nam, Min-Ho; Ahn, Kwang Seok; Choi, Seung-Hoon

    2013-01-01

    The discovery of adult neurogenesis was a turning point in the field of neuroscience. Adult neurogenesis offers an enormous possibility to open a new therapeutic paradigm of neurodegenerative diseases and stroke. Recently, several studies suggested that acupuncture may enhance adult neurogenesis. Acupuncture has long been an important treatment for brain diseases in the East Asia. The scientific mechanisms of acupuncture treatment for the diseases, such as Alzheimer's disease, Parkinson's disease, and stroke, have not been clarified yet; however, the neurogenic effect of acupuncture can be a possible reason. Here, we have reviewed the studies on the effect of stimulation at various acupoints for neurogenesis, such as ST36 and GV20. The suggested mechanisms are also discussed including upregulation of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, basic fibroblast growth factor and neuropeptide Y, and activation of the function of primo vascular system.

  18. Deep Brain Stimulation for Movement Disorders.

    Science.gov (United States)

    Revell, Maria A

    2015-12-01

    Disruption in the interaction between the central nervous system, nerves, and muscles cause movement disorders. These disorders can negatively affect quality of life. Deep brain stimulation (DBS) has been identified as a therapy for Parkinson disease and essential tremor that has significant advantages compared with medicinal therapies. Surgical intervention for these disorders before DBS included ablative therapies such as thalamotomy and pallidotomy. These procedures were not reversible and did not allow for treatment adjustments. The advent of DBS progressed therapies for significant movement disorders into the realm of being reversible and adjustable based on patient symptoms.

  19. Neuroprotective effects of vagus nerve stimulation on traumatic brain injury.

    Science.gov (United States)

    Zhou, Long; Lin, Jinhuang; Lin, Junming; Kui, Guoju; Zhang, Jianhua; Yu, Yigang

    2014-09-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of traumatic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain explosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1β and interleukin-10 concentrations were detected in serum and brain tissues, and water content in brain tissues was measured. Results showed that vagus nerve stimulation could reduce the degree of brain edema, decrease tumor necrosis factor-α and interleukin-1β concentrations, and increase interleukin-10 concentration after brain explosive injury in rabbits. These data suggest that vagus nerve stimulation may exert neuroprotective effects against explosive injury via regulating the expression of tumor necrosis factor-α, interleukin-1β and interleukin-10 in the serum and brain tissue.

  20. Neuroprotective effects of vagus nerve stimulation on traumatic brain injury

    Science.gov (United States)

    Zhou, Long; Lin, Jinhuang; Lin, Junming; Kui, Guoju; Zhang, Jianhua; Yu, Yigang

    2014-01-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of traumatic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain explosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1β and interleukin-10 concentrations were detected in serum and brain tissues, and water content in brain tissues was measured. Results showed that vagus nerve stimulation could reduce the degree of brain edema, decrease tumor necrosis factor-α and interleukin-1β concentrations, and increase interleukin-10 concentration after brain explosive injury in rabbits. These data suggest that vagus nerve stimulation may exert neuroprotective effects against explosive injury via regulating the expression of tumor necrosis factor-α, interleukin-1β and interleukin-10 in the serum and brain tissue. PMID:25368644

  1. Noninvasive deep brain stimulation using focused energy sources

    NARCIS (Netherlands)

    Sierra, C. V. Rizzo

    2010-01-01

    A non-invasive methodological possibility for brain stimulation through the simultaneous use of an external energy beam and an existing brain imaging system such as functional magnetic resonance imaging (fMRI) is herein proposed; the main advantage is to confine the stimulation into a single brain a

  2. Suppression and facilitation of auditory neurons through coordinated acoustic and midbrain stimulation: investigating a deep brain stimulator for tinnitus

    Science.gov (United States)

    Offutt, Sarah J.; Ryan, Kellie J.; Konop, Alexander E.; Lim, Hubert H.

    2014-12-01

    Objective. The inferior colliculus (IC) is the primary processing center of auditory information in the midbrain and is one site of tinnitus-related activity. One potential option for suppressing the tinnitus percept is through deep brain stimulation via the auditory midbrain implant (AMI), which is designed for hearing restoration and is already being implanted in deaf patients who also have tinnitus. However, to assess the feasibility of AMI stimulation for tinnitus treatment we first need to characterize the functional connectivity within the IC. Previous studies have suggested modulatory projections from the dorsal cortex of the IC (ICD) to the central nucleus of the IC (ICC), though the functional properties of these projections need to be determined. Approach. In this study, we investigated the effects of electrical stimulation of the ICD on acoustic-driven activity within the ICC in ketamine-anesthetized guinea pigs. Main Results. We observed ICD stimulation induces both suppressive and facilitatory changes across ICC that can occur immediately during stimulation and remain after stimulation. Additionally, ICD stimulation paired with broadband noise stimulation at a specific delay can induce greater suppressive than facilitatory effects, especially when stimulating in more rostral and medial ICD locations. Significance. These findings demonstrate that ICD stimulation can induce specific types of plastic changes in ICC activity, which may be relevant for treating tinnitus. By using the AMI with electrode sites positioned with the ICD and the ICC, the modulatory effects of ICD stimulation can be tested directly in tinnitus patients.

  3. Therapeutic Noninvasive Brain Stimulation in Alzheimer's Disease.

    Science.gov (United States)

    Gonsalvez, Irene; Baror, Roey; Fried, Peter; Santarnecchi, Emiliano; Pascual-Leone, Alvaro

    2017-01-01

    Alzheimer's disease (AD) is a looming public health crisis that currently lacks an effective treatment. Noninvasive Brain Stimulation (NBS), particularly transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), offers a promising alternative approach to pharmacological interventions for an increasing number of neurological and psychiatric conditions. The aim of this review is summarize data from therapeutic trials of NBS in AD and other dementing illnesses. Despite the potential of NBS, there is limited theoretical framework and a lack of guidelines for its applications to AD. Several published clinical trials failed to report key parameters of the interventions thus limiting the utility of the study to assess efficacy and safety. Our review concludes with some suggestions for future studies aimed to advance research into NBS as a potential treatment for the symptoms and disabilities caused by AD and to enable comparison of results across trials. Ultimately, appropriately powered, and controlled, multi-site randomized clinical trials will be needed to evaluate the therapeutic potential of NBS in AD.

  4. A steering electrode array for selective stimulation of sacral nerve roots

    NARCIS (Netherlands)

    Rodrigues, F.J.O.; Mendes, P.; Bartek, M.; Mimoun, B.A.Z.

    2011-01-01

    In this work a cylindrical electrode array to be used for electrical stimulation of sacral nerve roots is studied in respect to its ability to achieve selective stimulation of various spatial regions of the nerve bundle. Simulation results achieved on a simplified model consisting of 6 electrodes ev

  5. Neuroprotective effects of vagus nerve stimulation on traumatic brain injury

    OpenAIRE

    Zhou, Long; Lin, Jinhuang; Lin, Junming; Kui, Guoju; Zhang, Jianhua; Yu, Yigang

    2014-01-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of traumatic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain explosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1β and interleukin-10 concentrations were detected in serum and b...

  6. Entrainment of Perceptually Relevant Brain Oscillations by Non-Invasive Rhythmic Stimulation of the Human Brain

    OpenAIRE

    Thut, Gregor; Schyns, Philippe G.; Gross, Joachim

    2011-01-01

    The notion of driving brain oscillations by directly stimulating neuronal elements with rhythmic stimulation protocols has become increasingly popular in research on brain rhythms. Induction of brain oscillations in a controlled and functionally meaningful way would likely prove highly beneficial for the study of brain oscillations, and their therapeutic control. We here review conventional and new non-invasive brain stimulation protocols as to their suitability for controlled intervention in...

  7. Origin and evolution of deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Vittorio Alessandro eSironi

    2011-08-01

    Full Text Available This paper briefly describes how the electrical stimulation, used since antiquity to modulate the nervous system, has been a fundamental tool of neurophysiologic investigation in the second half of the 18th century and was subsequently used by the early 20th century, even for therapeutic purposes. In mid-20th century the advent of stereotactic procedures has allowed the drift from lesional to stimulating technique of deep nuclei of the brain for therapeutic purposes. In this way, DBS was born, that, over the last two decades, has led to positive results for the treatment of medically refractory Parkinson's disease, essential tremor and dystonia. In recent years, the indications for therapeutic use of DBS have been extended to epilepsy, Tourette's syndrome, psychiatric diseases (depression, obsessive-compulsive disorder, some kinds of headache, eating disorders and the minimally conscious state. The potentials of the DBS for therapeutic use are fascinating, but there are still many unresolved technical and ethical problems, concerning the identification of the targets for each disease, the selection of the patients and the evaluation of the results.

  8. Bilateral adaptive deep brain stimulation is effective in Parkinson's disease

    NARCIS (Netherlands)

    Little, Simon; Beudel, Martijn; Zrinzo, Ludvic; Foltynie, Thomas; Limousin, Patricia; Hariz, Marwan; Neal, Spencer; Cheeran, Binith; Cagnan, Hayriye; Gratwicke, James; Aziz, Tipu Z.; Pogosyan, Alex; Brown, Peter

    2016-01-01

    Introduction & objectives Adaptive deep brain stimulation (aDBS) uses feedback from brain signals to guide stimulation. A recent acute trial of unilateral aDBS showed that aDBS can lead to substantial improvements in contralateral hemibody Unified Parkinson's Disease Rating Scale (UPDRS) motor score

  9. Brain connectivity and sensory stimulation in disorders of consciousness

    OpenAIRE

    Heine, Lizette

    2016-01-01

    This thesis explores brain connectivity and sensory stimulation in patients with disorders of consciousness (DOC). These are serious conditions where massive brain damage can lead to a dissociation between arousal and awareness (e.g., UWS and MCS). Part I explores brain connectivity. We highlight that brain function and structure are intimately related to each other, and to consciousness. The decrease in brain function can be used to distinguish between the clinically indicated states of ...

  10. Control of a brain-computer interface using stereotactic depth electrodes in and adjacent to the hippocampus

    Science.gov (United States)

    Krusienski, D. J.; Shih, J. J.

    2011-04-01

    A brain-computer interface (BCI) is a device that enables severely disabled people to communicate and interact with their environments using their brain waves. Most research investigating BCI in humans has used scalp-recorded electroencephalography or intracranial electrocorticography. The use of brain signals obtained directly from stereotactic depth electrodes to control a BCI has not previously been explored. In this study, event-related potentials (ERPs) recorded from bilateral stereotactic depth electrodes implanted in and adjacent to the hippocampus were used to control a P300 Speller paradigm. The ERPs were preprocessed and used to train a linear classifier to subsequently predict the intended target letters. The classifier was able to predict the intended target character at or near 100% accuracy using fewer than 15 stimulation sequences in the two subjects tested. Our results demonstrate that ERPs from hippocampal and hippocampal adjacent depth electrodes can be used to reliably control the P300 Speller BCI paradigm.

  11. An implantable device for neuropsychiatric rehabilitation by chronic deep brain stimulation in freely moving rats

    Science.gov (United States)

    Wang, Chenguang; Zhang, Fuqiang; Jia, Hong

    2017-01-01

    Successful practice of clinical deep brain stimulation (DBS) calls for basic research on the mechanisms and explorations of new indications in animals. In the article, a new implantable, single-channel, low-power miniature device is proposed, which may transmit pulses chronically into the brain nucleus of freely moving rats. The DBS system consists of an implantable pulse generator (IPG), a bipolar electrode, and an external programmer. The IPG circuit module is assembled as a 20-mm diameter circular board and fixed on a rat’s skull together with an electrode and battery. The rigid electrode may make its fabrication and implantation more easy. The external programmer is designed for bidirectional communication with the IPG by a telecontrol transceiver and adjusts stimulation parameters. A biological validation was performed in which the effects of electrical stimulation in brain nucleus accumbens were detected. The programmed parameters were accurate, implant steady, and power sufficient to allow stimulation for more than 3 months. The larger area of the electrode tip provided a moderate current or charge density and minimized the damage from electrochemistry and pyroelectricity. The rats implanted with the device showed a reduction in morphine-induced conditioned place preference after high-frequency stimulation. In conclusion, the DBS device is based on the criteria of simple technology, minimal invasion, low cost, small in size, light-weight, and wireless controlled. This shows that our DBS device is appropriate and can be used for preclinical studies, indicating its potential utility in the therapy and rehabilitation of neuropsychiatric disorders. PMID:28121810

  12. Computational modeling of chemotactic signaling and aggregation of microglia around implantation site during deep brain stimulation

    Science.gov (United States)

    Silchenko, A. N.; Tass, P. A.

    2013-10-01

    It is well established that prolonged electrical stimulation of brain tissue causes massive release of ATP in the extracellular space. The released ATP and the products of its hydrolysis, such as ADP and adenosine, become the main elements mediating chemotactic sensitivity and motility of microglial cells via subsequent activation of P2Y2,12 as well as A3A and A2A adenosine receptors. The size of the sheath around the electrode formed by the microglial cells is an important criterion for the optimization of the parameters of electrical current delivered to brain tissue. Here, we study a purinergic signaling pathway underlying the chemotactic motion of microglia towards the implanted electrode during deep brain stimulation. We present a computational model describing formation of a stable aggregate around the implantation site due to the joint chemo-attractive action of ATP and ADP together with a mixed influence of extracellular adenosine. The model was built in accordance with the classical Keller-Segel approach and includes an equation for the cells' density as well as equations describing the hydrolysis of extracellular ATP via successive reaction steps ATP →ADP →AMP →adenosine. The results of our modeling allowed us to reveal the dependence of the width of the encapsulating layer around the electrode on the amount of ATP released due to permanent electrical stimulation. The dependences of the aggregates' size on the parameter governing the nonlinearity of interaction between extracellular adenosine and adenosine receptors are also analyzed.

  13. Ethical issues in deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Maartje eSchermer

    2011-05-01

    Full Text Available Deep brain stimulation (DBS is currently used to treat neurological disorders like Parkinson’s disease (PD, essential tremor and dystonia, and is explored as an experimental treatment for psychiatric disorders like Major Depression (MD and Obsessive Compulsive Disorder (OCD. This mini review discusses ethical issues in DBS treatment and research, as they have been discussed in the medical and ethical literature.With regard to DBS treatment, the most important issues are balancing risks and benefits and ensuring respect for the autonomous wish of the patient. This implies special attention to patient selection, psycho-social impact of treatment, effects on personal identity, and treatment of children. Moreover, it implies a careful informed consent process in which unrealistic expectations of patients and their families are addressed and in which special attention is given to competence. In the context of research, the fundamental ethical challenge is to promote high-quality scientific research in the interest of future patients, while at the same time safeguarding the rights and interests of vulnerable research subjects. Several guidelines have been proposed to ensure this. One of the preconditions to further development of responsible and transparent research practices is the establishment of a comprehensive registry.

  14. Body weight gain and deep brain stimulation.

    Science.gov (United States)

    Rieu, Isabelle; Derost, Philippe; Ulla, Miguel; Marques, Ana; Debilly, Bérangère; De Chazeron, Ingrid; Chéreau, Isabelle; Lemaire, Jean Jacques; Boirie, Yves; Llorca, Pierre Michel; Durif, Franck

    2011-11-15

    Deep brain stimulation (DBS) is a neurosurgical technique that has now been available for some 25 years. It is used in the treatment of various motor disorders, e.g. Parkinson's disease (PD), essential tremor and dystonia, and neuropsychiatric illnesses, e.g. obsessive-compulsive disorder and Tourette syndrome. The surgical targets of DBS include the thalamic ventralis intermedius nucleus (Vim), the globus pallidus internus (GPi) and more recently the subthalamic nucleus (STN), currently considered as the reference target in the treatment of PD. In the last ten years, most studies in PD patients have described a rapid and marked weight gain in the months following DBS of the STN. This weight gain sometimes induces obesity and can have metabolic repercussions. The physiopathological mechanisms responsible for the weight gain are multifactorial (changes in energy metabolism and eating behaviour, reduction of motor complications, etc.). This review reports current knowledge concerning weight changes in patients treated by DBS with different surgical targets. It also describes the mechanisms responsible for weight gain and the health outcome for the patients.

  15. Deep brain stimulation during early adolescence prevents microglial alterations in a model of maternal immune activation.

    Science.gov (United States)

    Hadar, Ravit; Dong, Le; Del-Valle-Anton, Lucia; Guneykaya, Dilansu; Voget, Mareike; Edemann-Callesen, Henriette; Schweibold, Regina; Djodari-Irani, Anais; Goetz, Thomas; Ewing, Samuel; Kettenmann, Helmut; Wolf, Susanne A; Winter, Christine

    2016-12-07

    In recent years schizophrenia has been recognized as a neurodevelopmental disorder likely involving a perinatal insult progressively affecting brain development. The poly I:C maternal immune activation (MIA) rodent model is considered as a neurodevelopmental model of schizophrenia. Using this model we and others demonstrated the association between neuroinflammation in the form of altered microglia and a schizophrenia-like endophenotype. Therapeutic intervention using the anti-inflammatory drug minocycline affected altered microglia activation and was successful in the adult offspring. However, less is known about the effect of preventive therapeutic strategies on microglia properties. Previously we found that deep brain stimulation of the medial prefrontal cortex applied pre-symptomatically to adolescence MIA rats prevented the manifestation of behavioral and structural deficits in adult rats. We here studied the effects of deep brain stimulation during adolescence on microglia properties in adulthood. We found that in the hippocampus and nucleus accumbens, but not in the medial prefrontal cortex, microglial density and soma size were increased in MIA rats. Pro-inflammatory cytokine mRNA was unchanged in all brain areas before and after implantation and stimulation. Stimulation of either the medial prefrontal cortex or the nucleus accumbens normalized microglia density and soma size in main projection areas including the hippocampus and in the area around the electrode implantation. We conclude that in parallel to an alleviation of the symptoms in the rat MIA model, deep brain stimulation has the potential to prevent the neuroinflammatory component in this disease.

  16. Rhythmic light stimulation modifies brain oscillations via entrainment

    Directory of Open Access Journals (Sweden)

    Annika eNotbohm

    2016-02-01

    Full Text Available The functional relevance of brain oscillations in the alpha frequency range (8-13Hz has been repeatedly investigated through the use of rhythmic visual stimulation. The underlying mechanism of the steady-state visual evoked potential (SSVEP measured in EEG during rhythmic stimulation, however, is not known. There are two hypotheses on the origin of the SSVEPs: entrainment of brain oscillations and superposition of event-related responses (ERPs. The entrainment but not the superposition hypothesis justifies rhythmic visual stimulation as a means to manipulate brain oscillations, because superposition assumes a linear summation of single responses, independent from ongoing brain oscillations. Here, we stimulated participants with a rhythmic flickering light of different frequencies and intensities.. We measured entrainment by comparing the phase coupling of brain oscillations stimulated by rhythmic visual flicker with the oscillations induced by arrhythmic jittered stimulation, varying the time, stimulation frequency, and intensity conditions. In line with a theoretical concept of entrainment (the so called Arnold tongue, we found the phase coupling to be more pronounced with increasing stimulation intensity as well as at stimulation frequencies closer to each participant’s intrinsic frequency. Only inside the Arnold tongue did the conditions significantly differ from the jittered stimulation. Furthermore, even in a single sequence of an SSVEP, we found non-linear features (intermittency of phase locking that contradict the linear summation of single responses, as assumed by the superposition hypothesis. Our findings provide unequivocal evidence that visual rhythmic stimulation entrains brain oscillations, thus validating the approach of rhythmic stimulation as a manipulation of brain oscillations.

  17. Theory of feedback controlled brain stimulations for Parkinson's disease

    Science.gov (United States)

    Sanzeni, A.; Celani, A.; Tiana, G.; Vergassola, M.

    2016-01-01

    Limb tremor and other debilitating symptoms caused by the neurodegenerative Parkinson's disease are currently treated by administering drugs and by fixed-frequency deep brain stimulation. The latter interferes directly with the brain dynamics by delivering electrical impulses to neurons in the subthalamic nucleus. While deep brain stimulation has shown therapeutic benefits in many instances, its mechanism is still unclear. Since its understanding could lead to improved protocols of stimulation and feedback control, we have studied a mathematical model of the many-body neural network dynamics controlling the dynamics of the basal ganglia. On the basis of the results obtained from the model, we propose a new procedure of active stimulation, that depends on the feedback of the network and that respects the constraints imposed by existing technology. We show by numerical simulations that the new protocol outperforms the standard ones for deep brain stimulation and we suggest future experiments that could further improve the feedback procedure.

  18. Dynamic impedance model of the skin-electrode interface for transcutaneous electrical stimulation.

    Directory of Open Access Journals (Sweden)

    José Luis Vargas Luna

    Full Text Available Transcutaneous electrical stimulation can depolarize nerve or muscle cells applying impulses through electrodes attached on the skin. For these applications, the electrode-skin impedance is an important factor which influences effectiveness. Various models describe the interface using constant or current-depending resistive-capacitive equivalent circuit. Here, we develop a dynamic impedance model valid for a wide range stimulation intensities. The model considers electroporation and charge-dependent effects to describe the impedance variation, which allows to describe high-charge pulses. The parameters were adjusted based on rectangular, biphasic stimulation pulses generated by a stimulator, providing optionally current or voltage-controlled impulses, and applied through electrodes of different sizes. Both control methods deliver a different electrical field to the tissue, which is constant throughout the impulse duration for current-controlled mode or have a very current peak for voltage-controlled. The results show a predominant dependence in the current intensity in the case of both stimulation techniques that allows to keep a simple model. A verification simulation using the proposed dynamic model shows coefficient of determination of around 0.99 in both stimulation types. The presented method for fitting electrode-skin impedance can be simple extended to other stimulation waveforms and electrode configuration. Therefore, it can be embedded in optimization algorithms for designing electrical stimulation applications even for pulses with high charges and high current spikes.

  19. Best of both worlds: Promise of combining brain stimulation and brain connectome

    Directory of Open Access Journals (Sweden)

    Caroline Di Bernardi Luft

    2014-07-01

    Full Text Available Transcranial current brain stimulation (tCS is becoming increasingly popular as a non-pharmacological non-invasive neuromodulatory method that alters cortical excitability by applying weak electrical currents to the scalp via a pair of electrodes. Most applications of this technique have focused on enhancing motor and learning skills, as well as a therapeutic agent in neurological and psychiatric disorders. In these applications, similarly to lesion studies, tCS was used to provide a causal link between a function or behaviour and a specific brain region (e.g., primary motor cortex. Nonetheless, complex cognitive functions are known to rely on functionally connected multitude of brain regions with dynamically changing patterns of information flow rather than on isolated areas, which are most commonly targeted in typical tCS experiments. In this review article, we argue in favour of combining tCS method with other neuroimaging techniques (e.g. fMRI, EEG and by employing state-of-the-art connectivity data analysis techniques (e.g. graph theory to obtain a deeper understanding of the underlying spatiotemporal dynamics of functional connectivity patterns and cognitive performance. Finally, we discuss the possibilities of these combined techniques to investigate the neural correlates of human creativity and to enhance creativity.

  20. Electrochemical properties of titanium nitride nerve stimulation electrodes: an in vitro and in vivo study.

    Science.gov (United States)

    Meijs, Suzan; Fjorback, Morten; Jensen, Carina; Sørensen, Søren; Rechendorff, Kristian; Rijkhoff, Nico J M

    2015-01-01

    The in vivo electrochemical behavior of titanium nitride (TiN) nerve stimulation electrodes was compared to their in vitro behavior for a period of 90 days. Ten electrodes were implanted in two Göttingen minipigs. Four of these were used for electrical stimulation and electrochemical measurements. Five electrodes were kept in Ringer's solution at 37.5°C, of which four were used for electrical stimulation and electrochemical measurements. The voltage transients measured in vivo were 13 times greater than in vitro at implantation and they continued to increase with time. The electrochemical properties in vivo and the tissue resistance (Rtissue) followed a similar trend with time. There was no consistent significant difference between the electrochemical properties of the in vivo and in vitro electrodes after the implanted period. The differences between the in vivo and in vitro electrodes during the implanted period show that the evaluation of electrochemical performance of implantable stimulation electrodes cannot be substituted with in vitro measurements. After the implanted period, however, the performance of the in vivo and in vitro electrodes in saline was similar. In addition, the changes observed over time during the post-implantation period regarding the electrochemical properties of the in vivo electrodes and Rtissue were similar, which indicates that these changes are due to the foreign body response to implantation.

  1. Muscle twitch responses for shaping the multi-pad electrode for functional electrical stimulation

    OpenAIRE

    Malešević Nebojša; Popović Lana; Bijelić Goran; Kvaščev Goran

    2010-01-01

    In this paper we present a method for optimization of multi-pad electrode spatial selectivity during transcutaneous Functional Electrical Stimulation (FES) of hand. The presented method is based on measurement of individual muscle twitch responses during low frequency electrical stimulation via pads within multi-pad electrode. Twitch responses are recorded by Micro-Electro-Mechanical Systems (MEMS) accelerometers. The aim of this methodology is to substitute bulky sensors, torque sensor...

  2. A multi-pad electrode based functional electrical stimulation system for restoration of grasp

    Directory of Open Access Journals (Sweden)

    Malešević Nebojša M

    2012-09-01

    Full Text Available Abstract Background Functional electrical stimulation (FES applied via transcutaneous electrodes is a common rehabilitation technique for assisting grasp in patients with central nervous system lesions. To improve the stimulation effectiveness of conventional FES, we introduce multi-pad electrodes and a new stimulation paradigm. Methods The new FES system comprises an electrode composed of small pads that can be activated individually. This electrode allows the targeting of motoneurons that activate synergistic muscles and produce a functional movement. The new stimulation paradigm allows asynchronous activation of motoneurons and provides controlled spatial distribution of the electrical charge that is delivered to the motoneurons. We developed an automated technique for the determination of the preferred electrode based on a cost function that considers the required movement of the fingers and the stabilization of the wrist joint. The data used within the cost function come from a sensorized garment that is easy to implement and does not require calibration. The design of the system also includes the possibility for fine-tuning and adaptation with a manually controllable interface. Results The device was tested on three stroke patients. The results show that the multi-pad electrodes provide the desired level of selectivity and can be used for generating a functional grasp. The results also show that the procedure, when performed on a specific user, results in the preferred electrode configuration characteristics for that patient. The findings from this study are of importance for the application of transcutaneous stimulation in the clinical and home environments.

  3. Non-invasive brain stimulation in early rehabilitation after stroke.

    Science.gov (United States)

    Blesneag, A V; Popa, L; Stan, A D

    2015-01-01

    The new tendency in rehabilitation involves non-invasive tools that, if applied early after stroke, promote neurorecovery. Repetitive transcranial magnetic stimulation and transcranial direct current stimulation may correct the disruption of cortical excitability and effectively contribute to the restoration of movement and speech. The present paper analyses the results of non-invasive brain stimulation (NIBS) trials, highlighting different aspects related to the repetitive transcranial magnetic stimulation frequency, transcranial direct current stimulation polarity, the period and stimulation places in acute and subacute ischemic strokes. The risk of adverse events, the association with motor or language recovery specific training, and the cumulative positive effect evaluation are also discussed.

  4. Optimization of Electrode Channels in Brain Computer Interfaces

    Science.gov (United States)

    Kamrunnahar, M.; Dias, N. S.; Schiff, S. J.

    2010-01-01

    What is the optimal number of electrodes one can use in discrimination of tasks for a Brain Computer Interface(BCI)? To address this question, the number and location of scalp electrodes in the acquisition of human electroencephalography (EEG) and discrimination of motor imagery tasks were optimized by using a systematic optimization approach. The systematic analysis results in the most reliable procedure in electrode optimization as well as a validating means for the other feature selection techniques. We acquired human scalp EEG in response to cue-based motor imagery tasks. We employed a systematic analysis by using all possible combinations of the channels and calculating task discrimination errors for each of these combinations by using linear discriminant analysis (LDA) for feature classification. Channel combination that resulted in the smallest discrimination error was selected as the optimum number of channels to be used in BCI applications. Results from the systematic analysis were compared with another feature selection algorithm: forward stepwise feature selection combined with LDA feature classification. Our results demonstrate the usefulness of the fully optimized technique for a reliable selection of scalp electrodes in BCI applications. PMID:19964437

  5. MEG can map short and long-term changes in brain activity following deep brain stimulation for chronic pain.

    Directory of Open Access Journals (Sweden)

    Hamid R Mohseni

    Full Text Available Deep brain stimulation (DBS has been shown to be clinically effective for some forms of treatment-resistant chronic pain, but the precise mechanisms of action are not well understood. Here, we present an analysis of magnetoencephalography (MEG data from a patient with whole-body chronic pain, in order to investigate changes in neural activity induced by DBS for pain relief over both short- and long-term. This patient is one of the few cases treated using DBS of the anterior cingulate cortex (ACC. We demonstrate that a novel method, null-beamforming, can be used to localise accurately brain activity despite the artefacts caused by the presence of DBS electrodes and stimulus pulses. The accuracy of our source localisation was verified by correlating the predicted DBS electrode positions with their actual positions. Using this beamforming method, we examined changes in whole-brain activity comparing pain relief achieved with deep brain stimulation (DBS ON and compared with pain experienced with no stimulation (DBS OFF. We found significant changes in activity in pain-related regions including the pre-supplementary motor area, brainstem (periaqueductal gray and dissociable parts of caudal and rostral ACC. In particular, when the patient reported experiencing pain, there was increased activity in different regions of ACC compared to when he experienced pain relief. We were also able to demonstrate long-term functional brain changes as a result of continuous DBS over one year, leading to specific changes in the activity in dissociable regions of caudal and rostral ACC. These results broaden our understanding of the underlying mechanisms of DBS in the human brain.

  6. Calibration of clinical cerebellar and deep brain stimulation systems.

    Science.gov (United States)

    McLellan, D L; Wright, G D; Renouf, F

    1981-01-01

    The increasing use of electrical stimulation of the brain for relief of pain, spasticity and epilepsy has introduced unfamiliar techniques into clinical neurological and neurosurgical practice. In view of the evidence that excessive levels of stimulation can damage brain tissue, it is of great importance to monitor the dose of stimulation. A review of recent clinical papers suggests that many centres do not measure the dose accurately, relying on arbitrary dial settings on external transmitters. This paper reviews that factors that affect the dose received by the patient and suggests methods of measuring them, at operation and subsequently, which should routinely be employed by clinicians implanting stimulators. Images PMID:6973614

  7. Neuropsychiatric Outcome of an Adolescent Who Received Deep Brain Stimulation for Tourette's Syndrome

    Directory of Open Access Journals (Sweden)

    S. J. Pullen

    2011-01-01

    Full Text Available This case study followed one adolescent patient who underwent bilateral deep brain stimulation of the centromedian parafascicular complex (CM-Pf for debilitating, treatment refractory Tourette's syndrome for a period of 1.5 years. Neurocognitive testing showed no significant changes between baseline and follow-up assessments. Psychiatric assessment revealed positive outcomes in overall adaptive functioning and reduction in psychotropic medication load in this patient. Furthermore, despite significant baseline psychiatric comorbidity, this patient reported no suicidal ideation following electrode implantation. Deep brain stimulation is increasingly being used in children and adolescents. This case reports on the positive neurologic and neuropsychiatric outcome of an adolescent male with bilateral CM-Pf stimulation.

  8. Deep brain stimulation mechanisms: the control of network activity via neurochemistry modulation.

    Science.gov (United States)

    McIntyre, Cameron C; Anderson, Ross W

    2016-10-01

    Deep brain stimulation (DBS) has revolutionized the clinical care of late-stage Parkinson's disease and shows promise for improving the treatment of intractable neuropsychiatric disorders. However, after over 25 years of clinical experience, numerous questions still remain on the neurophysiological basis for the therapeutic mechanisms of action. At their fundamental core, the general purpose of electrical stimulation therapies in the nervous system are to use the applied electric field to manipulate the opening and closing of voltage-gated sodium channels on neurons, generate stimulation induced action potentials, and subsequently, control the release of neurotransmitters in targeted pathways. Historically, DBS mechanisms research has focused on characterizing the effects of stimulation on neurons and the resulting impact on neuronal network activity. However, when electrodes are placed within the central nervous system, glia are also being directly (and indirectly) influenced by the stimulation. Mounting evidence shows that non-neuronal tissue can play an important role in modulating the neurochemistry changes induced by DBS. The goal of this review is to evaluate how DBS effects on both neuronal and non-neuronal tissue can potentially work together to suppress oscillatory activity (and/or information transfer) between brain regions. These resulting effects of ~ 100 Hz electrical stimulation help explain how DBS can disrupt pathological network activity in the brain and generate therapeutic effects in patients. Deep brain stimulation is an effective clinical technology, but detailed therapeutic mechanisms remain undefined. This review provides an overview of the leading hypotheses, which focus on stimulation-induced disruption of network oscillations and integrates possible roles for non-neuronal tissue in explaining the clinical response to therapeutic stimulation. This article is part of a special issue on Parkinson disease.

  9. Modulating Hippocampal Plasticity with In Vivo Brain Stimulation

    Science.gov (United States)

    2015-09-16

    and memory . Understanding such molecular effects will lead to a better understanding of the mechanisms by which brain stimulation produces its effects...critical for learning and memory . Understanding such molecular effects will lead to a better understanding of the mechanisms by which brain stimulation...effects remains elusive. Based on past studies on the enhance- ment of learning and memory in both human and animals, there is a general consensus that

  10. Measuring and modulating the brain with non-invasive stimulation

    NARCIS (Netherlands)

    Munneke, M.A.M

    2014-01-01

    The overall goal of the studies in this thesis was the use of non-invasive brain stimulation for measuring and modulating corticospinal excitability and to study the possibility of therapeutic modulation of excitability in some neurological disorders. Brain modulation to reduce the over-excitability

  11. New modalities of brain stimulation for stroke rehabilitation

    OpenAIRE

    Edwardson, M. A.; Lucas, T. H.; Carey, J. R.; Fetz, E. E.

    2012-01-01

    Stroke is a leading cause of disability, and the number of stroke survivors continues to rise. Traditional neurorehabilitation strategies aimed at restoring function to weakened limbs provide only modest benefit. New brain stimulation techniques designed to augment traditional neurorehabilitation hold promise for reducing the burden of stroke-related disability. Investigators discovered that repetitive transcranial magnetic stimulation (rTMS), trans-cranial direct current stimulation (tDCS), ...

  12. An energy-efficient, adiabatic electrode stimulator with inductive energy recycling and feedback current regulation.

    Science.gov (United States)

    Arfin, Scott K; Sarpeshkar, Rahul

    2012-02-01

    In this paper, we present a novel energy-efficient electrode stimulator. Our stimulator uses inductive storage and recycling of energy in a dynamic power supply. This supply drives an electrode in an adiabatic fashion such that energy consumption is minimized. It also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The dynamic power supply allows efficient transfer of energy both to and from the electrode and is based on a DC-DC converter topology that we use in a bidirectional fashion in forward-buck or reverse-boost modes. In an exemplary electrode implementation intended for neural stimulation, we show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard .35 μm CMOS process. This stimulator achieves a 2x-3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply. We perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. This theoretical analysis reveals that further improvements in energy efficiency may be achievable with better implementations in the future. Our electrode stimulator could be widely useful for neural, cardiac, retinal, cochlear, muscular and other biomedical implants where low power operation is important.

  13. Application of Preoperative CT/MRI Image Fusion in Target Positioning for Deep Brain Stimulation

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Zi-yuan Liu; Wan-chen Dou; Wen-bin Ma; Ren-zhi Wang; Yi Guo

    2016-01-01

    Objective To explore the efficacy of target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation. Methods We retrospectively analyzed the clinical data and images of 79 cases (68 with Parkinson’s disease, 11 with dystonia) who received preoperative CT/MRI image fusion in target positioning of subthalamic nucleus in deep brain stimulation. Deviation of implanted electrodes from the target nucleus of each patient were measured. Neurological evaluations of each patient before and after the treatment were performed and compared. Complications of the positioning and treatment were recorded. Results The mean deviations of the electrodes implanted on X, Y, and Z axis were 0.5 mm, 0.6 mm, and 0.6 mm, respectively. Postoperative neurologic evaluations scores of unified Parkinson’s disease rating scale (UPDRS) for Parkinson’s disease and Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) for dystonia patients improved significantly compared to the preoperative scores (P<0.001); Complications occurred in 10.1% (8/79) patients, and main side effects were dysarthria and diplopia. Conclusion Target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation has high accuracy and good clinical outcomes.

  14. Vascular changes caused by deep brain stimulation using double-dose gadolinium-enhanced brain MRI

    Institute of Scientific and Technical Information of China (English)

    Byeong Sam Choi; Yong Hwan Kim; Sang Ryong Jeon

    2014-01-01

    We retrospectively analyzed the clinical data of 32 patients with medically intractable idiopathic Parkinson’s disease who had undergone staged bilateral deep brain stimulation of the subtha-lamic nuclei from January 2007 to May 2011. The vascularture of the patients who received two deep brain stimulations was detected using double-dose gadolinium-enhanced brain MRI. The dimensions of straight sinus, superior sagittal sinus, ipsilateral internal cerebral vein in the tha-lamic branch and ipsilateral anterior caudate vein were reduced. These ifndings demonstrate that bilateral deep brain stimulation of the subthalamic nuclei affects cerebral venous blood lfow.

  15. Quasi-monopolar stimulation: a novel electrode design configuration for performance optimization of a retinal neuroprosthesis.

    Directory of Open Access Journals (Sweden)

    Gita Khalili Moghadam

    Full Text Available In retinal neuroprostheses, spatial interaction between electric fields from various electrodes - electric crosstalk - may occur in multielectrode arrays during simultaneous stimulation of the retina. Depending on the electrode design and placement, this crosstalk can either enhance or degrade the functional characteristics of a visual prosthesis. To optimize the device performance, a balance must be satisfied between the constructive interference of crosstalk on dynamic range and power consumption and its negative effect on artificial visual acuity. In the present computational modeling study, we have examined the trade-off in these positive and negative effects using a range of currently available electrode array configurations, compared to a recently proposed stimulation strategy - the quasi monopolar (QMP configuration - in which the return current is shared between local bipolar guards and a distant monopolar electrode. We evaluate the performance of the QMP configuration with respect to the implantation site and electrode geometry parameters. Our simulation results demonstrate that the beneficial effects of QMP are only significant at electrode-to-cell distances greater than the electrode dimensions. Possessing a relatively lower activation threshold, QMP was found to be superior to the bipolar configuration in terms of providing a relatively higher visual acuity. However, the threshold for QMP was more sensitive to the topological location of the electrode in the array, which may need to be considered when programming the manner in which electrode are simultaneously activated. This drawback can be offset with a wider dynamic range and lower power consumption of QMP. Furthermore, the ratio of monopolar return current to total return can be used to adjust the functional performance of QMP for a given implantation site and electrode parameters. We conclude that the QMP configuration can be used to improve visual information-to-stimulation

  16. [Functional imaging of deep brain stimulation in idiopathic Parkinson's disease].

    Science.gov (United States)

    Hilker, R

    2010-10-01

    Functional brain imaging allows the effects of deep brain stimulation (DBS) on the living human brain to be investigated. In patients with advanced Parkinson's disease (PD), positron emission tomography (PET) studies were undertaken at rest as well as under motor, cognitive or behavioral activation. DBS leads to a reduction of abnormal PD-related network activity in the motor system, which partly correlates with the improvement of motor symptoms. The local increase of energy consumption within the direct target area suggests a predominant excitatory influence of the stimulation current on neuronal tissue. Remote effects of DBS of the subthalamic nucleus (STN) on frontal association cortices indicate an interference of stimulation energy with associative and limbic basal ganglia loops. Taken together, functional brain imaging provides very valuable data for advancement of the DBS technique in PD therapy.

  17. Emotion recognition in Parkinson's disease after subthalamic deep brain stimulation: differential effects of microlesion and STN stimulation.

    Science.gov (United States)

    Aiello, Marilena; Eleopra, Roberto; Lettieri, Christian; Mondani, Massimo; D'Auria, Stanislao; Belgrado, Enrico; Piani, Antonella; De Simone, Luca; Rinaldo, Sara; Rumiati, Raffaella I

    2014-02-01

    Deep brain stimulation of the subthalamic nucleus (STN-DBS) has acquired a relevant role in the treatment of Parkinson's disease (PD). Despite being a safe procedure, it may expose patients to an increased risk to experience cognitive and emotional difficulties. Impairments in emotion recognition, mediated both by facial and prosodic expressions, have been reported in PD patients treated with such procedure. However, it is still unclear whether the STN per se is responsible for such changes or whether others factors like the microlesion produced by the electrode implantation may also play a role. In this study we evaluated facial emotions discrimination and emotions recognition using both facial and prosodic expressions in 12 patients with PD and 13 matched controls. Patients' were tested in four conditions: before surgery, both in on and off medication, and after surgery, respectively few days after STN implantation before turning stimulator on and few months after with stimulation on. We observed that PD patients were impaired in discriminating and recognizing facial emotions, especially disgust, even before DBS implant. Microlesion caused by surgical procedure was found to influence patients' performance on the discrimination task and recognition of sad facial expression while, after a few months of STN stimulation, impaired disgust recognition was again prominent. No impairment in emotional prosody recognition was observed both before and after surgery. Our study confirms that PD patients may experience a deficit in disgust recognition and provides insight into the differential effect of microlesion and stimulation of STN on several tasks assessing emotion recognition.

  18. Quasi-Monopolar Stimulation: A Novel Electrode Design Configuration for Performance Optimization of a Retinal Neuroprosthesis

    OpenAIRE

    2013-01-01

    In retinal neuroprostheses, spatial interaction between electric fields from various electrodes - electric crosstalk - may occur in multielectrode arrays during simultaneous stimulation of the retina. Depending on the electrode design and placement, this crosstalk can either enhance or degrade the functional characteristics of a visual prosthesis. To optimize the device performance, a balance must be satisfied between the constructive interference of crosstalk on dynamic range and power consu...

  19. Stimulating at the right time: phase-specific deep brain stimulation

    Science.gov (United States)

    Pedrosa, David; Little, Simon; Pogosyan, Alek; Cheeran, Binith; Aziz, Tipu; Green, Alexander; Fitzgerald, James; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Friston, Karl J.; Denison, Timothy; Brown, Peter

    2017-01-01

    See Moll and Engel (doi:10.1093/aww308) for a scientific commentary on this article. Brain regions dynamically engage and disengage with one another to execute everyday actions from movement to decision making. Pathologies such as Parkinson’s disease and tremor emerge when brain regions controlling movement cannot readily decouple, compromising motor function. Here, we propose a novel stimulation strategy that selectively regulates neural synchrony through phase-specific stimulation. We demonstrate for the first time the therapeutic potential of such a stimulation strategy for the treatment of patients with pathological tremor. Symptom suppression is achieved by delivering stimulation to the ventrolateral thalamus, timed according to the patient’s tremor rhythm. Sustained locking of deep brain stimulation to a particular phase of tremor afforded clinically significant tremor relief (up to 87% tremor suppression) in selected patients with essential tremor despite delivering less than half the energy of conventional high frequency stimulation. Phase-specific stimulation efficacy depended on the resonant characteristics of the underlying tremor network. Selective regulation of neural synchrony through phase-locked stimulation has the potential to both increase the efficiency of therapy and to minimize stimulation-induced side effects. PMID:28007997

  20. Coupling brain-machine interfaces with cortical stimulation for brain-state dependent stimulation: enhancing motor cortex excitability for neurorehabilitation

    Directory of Open Access Journals (Sweden)

    Alireza eGharabaghi

    2014-03-01

    Full Text Available Motor recovery after stroke is an unsolved challenge despite intensive rehabilitation training programs. Brain stimulation techniques have been explored in addition to traditional rehabilitation training to increase the excitability of the stimulated motor cortex. This modulation of cortical excitability augments the response to afferent input during motor exercises, thereby enhancing skilled motor learning by long-term potentiation-like plasticity. Recent approaches examined brain stimulation applied concurrently with voluntary movements to induce more specific use-dependent neural plasticity during motor training for neurorehabilitation. Unfortunately, such approaches are not applicable for the many severely affected stroke patients lacking residual hand function. These patients require novel activity-dependent stimulation paradigms based on intrinsic brain activity. Here, we report on such brain state-dependent stimulation (BSDS combined with haptic feedback provided by a robotic hand orthosis. Transcranial magnetic stimulation of the motor cortex and haptic feedback to the hand were controlled by sensorimotor desynchronization during motor-imagery and applied within a brain-machine interface environment in one healthy subject and one patient with severe hand paresis in the chronic phase after stroke. BSDS significantly increased the excitability of the stimulated motor cortex in both healthy and post-stroke conditions, an effect not observed in non-BSDS protocols. This feasibility study suggests that closing the loop between intrinsic brain state, cortical stimulation and haptic feedback provides a novel neurorehabilitation strategy for stroke patients lacking residual hand function, a proposal that warrants further investigation in a larger cohort of stroke patients.

  1. New perspectives on using brain imaging to study CNS stimulants.

    Science.gov (United States)

    Lukas, Scott E

    2014-12-01

    While the recent application of brain imaging to study CNS stimulants has offered new insights into the fundamental factors that contribute to their use and abuse, many gaps remain. Brain circuits that mediate pleasure, dependence, craving and relapse are anatomically, neurophysiologically and neurochemically distinct from one another, which has guided the search for correlates of stimulant-seeking and taking behavior. However, unlike other drugs of abuse, metrics for tolerance and physical dependence on stimulants are not obvious. The dopamine theory of stimulant abuse does not sufficiently explain this disorder as serotonergic, GABAergic and glutamagergic circuits are clearly involved in stimulant pharmacology and so tracking the source of the "addictive" processes must adopt a more multimodal, multidisciplinary approach. To this end, both anatomical and functional magnetic resonance imaging (MRI), MR spectroscopy (MRS) and positron emission tomography (PET) are complementary and have equally contributed to our understanding of how stimulants affect the brain and behavior. New vistas in this area include nanotechnology approaches to deliver small molecules to receptors and use MRI to resolve receptor dynamics. Anatomical and blood flow imaging has yielded data showing that cognitive enhancers might be useful adjuncts in treating CNS stimulant dependence, while MRS has opened opportunities to examine the brain's readiness to accept treatment as GABA tone normalizes after detoxification. A desired outcome of the above approaches is being able to offer evidence-based rationales for treatment approaches that can be implemented in a more broad geographic area, where access to brain imaging facilities may be limited. This article is part of the Special Issue entitled 'CNS Stimulants'.

  2. Deep brain stimulation in the lateral orbitofrontal cortex impairs spatial reversal learning.

    Science.gov (United States)

    Klanker, Marianne; Post, Ger; Joosten, Ruud; Feenstra, Matthijs; Denys, Damiaan

    2013-05-15

    Deep Brain Stimulation (DBS) is a successful novel treatment for treatment-resistant obsessive-compulsive disorder and is currently under investigation for addiction and eating disorders. Clinical and preclinical studies have shown functional changes in the orbitofrontal cortex (OFC) following DBS in the ventral capsule/ventral striatum. These findings suggest that DBS can affect neural activity in distant regions that are connected to the site of electrode implantation. However, the behavioral consequences of direct OFC stimulation are not known. Here, we studied the effects of direct stimulation in the lateral OFC on spatial discrimination and reversal learning in rats. Rats were implanted with stimulating electrodes and were trained on a spatial discrimination and reversal learning task. DBS in the OFC did not affect acquisition of a spatial discrimination. Stimulated animals made more incorrect responses during the first reversal. Acquisition of the second reversal was not affected. These results suggest that DBS may inhibit activity in the OFC, or may disrupt output of the OFC to other cortical or subcortical areas, resulting in perseverative behavior or an inability to adapt behavior to altered response-reward contingencies.

  3. [Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche].

    Science.gov (United States)

    Helmich, R C; Snijders, A H; Verkes, R J; Bloem, B R

    2004-02-28

    Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The changes occur locally as well as at a distance in functionally connected brain areas. These features render rTMS a suitable tool to study normal brain functions and the pathophysiology of brain diseases. Furthermore, it is expected that rTMS could be used as a novel therapy for neurological or psychiatric diseases characterised by abnormal cortical activation. This possibility has been studied mostly in patients suffering from depression, where rTMS has been used to restore normal activity in the hypoactive prefrontal cortex. Despite statistically significant therapeutic effects in small sized trials, the clinical implications are still limited.

  4. Electrode contact configuration and energy consumption in spinal cord stimulation

    NARCIS (Netherlands)

    Vos, de Cecile C.; Hilgerink, Marjolein P.; Buschman, Hendrik P.J.; Holsheimer, Jan

    2009-01-01

    Objective: To test the hypothesis that in spinal cord stimulation, in contrast to an increase of the number of anodes which reduces energy consumption per pulse, an increase of the number of cathodes raises the energy per pulse. Methods: Patients with an Itrel 3 pulse generator and a Pisces Quad qu

  5. Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract)

    Science.gov (United States)

    Ueno, S.; Matsuda, T.

    1991-04-01

    We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.

  6. Quantitative analysis of axonal fiber activation evoked by deep brain stimulation via activation density heat maps

    Directory of Open Access Journals (Sweden)

    Christian J. Hartmann

    2015-02-01

    Full Text Available Background: Cortical modulation is likely to be involved in the various therapeutic effects of deep brain stimulation (DBS. However, it is currently difficult to predict the changes of cortical modulation during clinical adjustment of DBS. Therefore, we present a novel quantitative approach to estimate anatomical regions of DBS-evoked cortical modulation. Methods: Four different models of the subthalamic nucleus (STN DBS were created to represent variable electrode placements (model I: dorsal border of the posterolateral STN; model II: central posterolateral STN; model III: central anteromedial STN; model IV: dorsal border of the anteromedial STN. Axonal fibers of passage near each electrode location were reconstructed using probabilistic tractography and modeled using multi-compartment cable models. Stimulation-evoked activation of local axon fibers and corresponding cortical projections were modeled and quantified. Results: Stimulation at the border of the STN (models I and IV led to a higher degree of fiber activation and associated cortical modulation than stimulation deeply inside the STN (models II and III. A posterolateral target (models I and II was highly connected to cortical areas representing motor function. Additionally, model I was also associated with strong activation of fibers projecting to the cerebellum. Finally, models III and IV showed a dorsoventral difference of preferentially targeted prefrontal areas (models III: middle frontal gyrus; model IV: inferior frontal gyrus.Discussion: The method described herein allows characterization of cortical modulation across different electrode placements and stimulation parameters. Furthermore, knowledge of anatomical distribution of stimulation-evoked activation targeting cortical regions may help predict efficacy and potential side effects, and therefore can be used to improve the therapeutic effectiveness of individual adjustments in DBS patients.

  7. Analyzing the tradeoff between electrical complexity and accuracy in patient-specific computational models of deep brain stimulation

    Science.gov (United States)

    Howell, Bryan; McIntyre, Cameron C.

    2016-06-01

    Objective. Deep brain stimulation (DBS) is an adjunctive therapy that is effective in treating movement disorders and shows promise for treating psychiatric disorders. Computational models of DBS have begun to be utilized as tools to optimize the therapy. Despite advancements in the anatomical accuracy of these models, there is still uncertainty as to what level of electrical complexity is adequate for modeling the electric field in the brain and the subsequent neural response to the stimulation. Approach. We used magnetic resonance images to create an image-based computational model of subthalamic DBS. The complexity of the volume conductor model was increased by incrementally including heterogeneity, anisotropy, and dielectric dispersion in the electrical properties of the brain. We quantified changes in the load of the electrode, the electric potential distribution, and stimulation thresholds of descending corticofugal (DCF) axon models. Main results. Incorporation of heterogeneity altered the electric potentials and subsequent stimulation thresholds, but to a lesser degree than incorporation of anisotropy. Additionally, the results were sensitive to the choice of method for defining anisotropy, with stimulation thresholds of DCF axons changing by as much as 190%. Typical approaches for defining anisotropy underestimate the expected load of the stimulation electrode, which led to underestimation of the extent of stimulation. More accurate predictions of the electrode load were achieved with alternative approaches for defining anisotropy. The effects of dielectric dispersion were small compared to the effects of heterogeneity and anisotropy. Significance. The results of this study help delineate the level of detail that is required to accurately model electric fields generated by DBS electrodes.

  8. Early responses to deep brain stimulation in depression are modulated by anti-inflammatory drugs.

    Science.gov (United States)

    Perez-Caballero, L; Pérez-Egea, R; Romero-Grimaldi, C; Puigdemont, D; Molet, J; Caso, J-R; Mico, J-A; Pérez, V; Leza, J-C; Berrocoso, E

    2014-05-01

    Deep brain stimulation (DBS) in the subgenual cingulated gyrus (SCG) is a promising new technique that may provide sustained remission in resistant major depressive disorder (MDD). Initial studies reported a significant early improvement in patients, followed by a decline within the first month of treatment, an unexpected phenomenon attributed to potential placebo effects or a physiological response to probe insertion that remains poorly understood. Here we characterized the behavioural antidepressant-like effect of DBS in the rat medial prefrontal cortex, focusing on modifications to rodent SCG correlate (prelimbic and infralimbic (IL) cortex). In addition, we evaluated the early outcome of DBS in the SCG of eight patients with resistant MDD involved in a clinical trial. We found similar antidepressant-like effects in rats implanted with electrodes, irrespective of whether they received electrical brain stimulation or not. This effect was due to regional inflammation, as it was temporally correlated with an increase of glial-fibrillary-acidic-protein immunoreactivity, and it was blocked by anti-inflammatory drugs. Indeed, inflammatory mediators and neuronal p11 expression also changed. Furthermore, a retrospective study indicated that the early response of MDD patients subjected to DBS was poorer when they received anti-inflammatory drugs. Our study demonstrates that electrode implantation up to the IL cortex is sufficient to produce an antidepressant-like effect of a similar magnitude to that observed in rats receiving brain stimulation. Moreover, both preclinical and clinical findings suggest that the use of anti-inflammatory drugs after electrode implantation may attenuate the early anti-depressive response in patients who are subjected to DBS.

  9. Non-invasive Brain Stimulation for Essential Tremor

    Science.gov (United States)

    Shih, Ludy C.; Pascual-Leone, Alvaro

    2017-01-01

    Background There is increasing interest in the use of non-invasive brain stimulation to characterize and potentially treat essential tremor (ET). Studies have used a variety of stimulation coils, paradigms, and target locations to make these observations. We reviewed the literature to compare prior studies and to evaluate the rationale and the methods used in these studies. Methods We performed a systematic literature search of the PubMed database using the terms “transcranial,” “noninvasive,” “brain stimulation,” “transcranial magnetic stimulation (TMS),” “transcranial direct current stimulation (tDCS),” “transcranial alternating current stimulation (tACS),” and “essential tremor.” Results Single pulses of TMS to the primary motor cortex have long been known to reset tremor. Although there are relatively few studies showing alterations in motor cortical physiology, such as motor threshold, short and long intracortical inhibition, and cortical silent period, there may be some evidence of altered intracortical facilitation and cerebello-brain inhibition in ET. Repetitive TMS, theta burst stimulation, tDCS, and tACS have been applied to human subjects with tremor with some preliminary signs of tremor reduction, particularly in those studies that employed consecutive daily sessions. Discussion A variety of stimulation paradigms and targets have been explored, with the increasing rationale an interest in targeting the cerebellum. Rigorous assessment of coil geometry, stimulation paradigm, rationale for selection of the specific anatomic target, and careful phenotypic and physiologic characterization of the subjects with ET undergoing these interventions may be critical in extending these preliminary findings into effective stimulation therapies. PMID:28373927

  10. Conformable actively multiplexed high-density surface electrode array for brain interfacing

    Science.gov (United States)

    Rogers, John; Kim, Dae-Hyeong; Litt, Brian; Viventi, Jonathan

    2015-01-13

    Provided are methods and devices for interfacing with brain tissue, specifically for monitoring and/or actuation of spatio-temporal electrical waveforms. The device is conformable having a high electrode density and high spatial and temporal resolution. A conformable substrate supports a conformable electronic circuit and a barrier layer. Electrodes are positioned to provide electrical contact with a brain tissue. A controller monitors or actuates the electrodes, thereby interfacing with the brain tissue. In an aspect, methods are provided to monitor or actuate spatio-temporal electrical waveform over large brain surface areas by any of the devices disclosed herein.

  11. Direct cortical stimulation but not transcranial electrical stimulation motor evoked potentials detect brain ischemia during brain tumor resection.

    Science.gov (United States)

    Li, Fenghua; Deshaies, Eric M; Allott, Geoffrey; Canute, Gregory; Gorji, Reza

    2011-09-01

    Motor evoked potentials (MEPs) elicited by both direct cortical stimulation (DCS) and transcranial electrical stimulation are used during brain tumor resection. Parallel use of direct cortical stimulation motor evoked potentials (DCS-MEPs) and transcranial electrical stimulation motor evoked potentials (TCeMEPs) has been practiced during brain tumor resection. We report that DCS-MEPs elicited by direct subdural grid stimulation, but not TCeMEPs, detected brain ischemia during brain tumor resection. Following resection of a brainstem high-grade glioma in a 21-year-old, the threshold of cortical motor-evoked-potentials (cMEPs) increased from 13 mA to 20 mA while amplitudes decreased. No changes were noted in transcranial motor evoked potentials (TCMEPs), somatosensory evoked potentials (SSEPs), auditory evoked potentials (AEPs), anesthetics, or hemodynamic parameters. Our case showed the loss of cMEPs and SSEPs, but not TCeMEPs. Permanent loss of DCS-MEPs and SSEPs was correlated with permanent left hemiplegia in our patient even when appropriate action was taken. Parallel use of DCS- and TCeMEPs with SSEPs improves sensitivity of intraoperative detection of motor impairment. DCS may be superior to TCeMEPs during brain tumor resection.

  12. Measurements and models of electric fields in the in vivo human brain during transcranial electric stimulation

    Science.gov (United States)

    Huang, Yu; Liu, Anli A; Lafon, Belen; Friedman, Daniel; Dayan, Michael; Wang, Xiuyuan; Bikson, Marom; Doyle, Werner K; Devinsky, Orrin; Parra, Lucas C

    2017-01-01

    Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intracranially in ten epilepsy patients and estimated electric fields across the entire brain by leveraging calibrated current-flow models. When stimulating at 2 mA, cortical electric fields reach 0.4 V/m, the lower limit of effectiveness in animal studies. When individual whole-head anatomy is considered, the predicted electric field magnitudes correlate with the recorded values in cortical (r = 0.89) and depth (r = 0.84) electrodes. Accurate models require adjustment of tissue conductivity values reported in the literature, but accuracy is not improved when incorporating white matter anisotropy or different skull compartments. This is the first study to validate and calibrate current-flow models with in vivo intracranial recordings in humans, providing a solid foundation to target stimulation and interpret clinical trials. DOI: http://dx.doi.org/10.7554/eLife.18834.001 PMID:28169833

  13. Deep Brain Stimulation for Essential Vocal Tremor: A Technical Report.

    Science.gov (United States)

    Ho, Allen L; Choudhri, Omar; Sung, C Kwang; DiRenzo, Elizabeth E; Halpern, Casey H

    2015-03-01

    Essential vocal tremor (EVT) is the presence of a tremulous voice that is commonly associated with essential tremor. Patients with EVT often report a necessary increase in vocal effort that significantly worsens with stress and anxiety and can significantly impact quality of life despite optimal medical and behavioral treatment options. Deep brain stimulation (DBS) has been proposed as an effective therapy for vocal tremor, but very few studies exist in the literature that comprehensively evaluate the efficacy of DBS for specifically addressing EVT. We present a technical report on our multidisciplinary, comprehensive operative methodology for treatment of EVT with frameless, awake deep brain stimulation (DBS).

  14. Entrainment of perceptually relevant brain oscillations by non-invasive rhythmic stimulation of the human brain

    Directory of Open Access Journals (Sweden)

    Gregor eThut

    2011-07-01

    Full Text Available The notion of driving brain oscillations by directly stimulating neuronal elements with rhythmic stimulation protocols has become increasingly popular in research on brain rhythms. Induction of brain oscillations in a controlled and functionally meaningful way would likely prove highly beneficial for the study of brain oscillations, and their therapeutic control. We here review conventional and new non-invasive brain stimulation protocols as to their suitability for controlled intervention into human brain oscillations. We focus on one such type of intervention, the direct entrainment of brain oscillations by a periodic external drive. We review highlights of the literature on entraining brain rhythms linked to perception and attention, and point out controversies. Behaviourally, such entrainment seems to alter specific aspects of perception depending on the frequency of stimulation, informing models on the functional role of oscillatory activity. This indicates that human brain oscillations and function may be promoted in a controlled way by focal entrainment, with great potential for probing into brain oscillations and their causal role.

  15. Entrainment of perceptually relevant brain oscillations by non-invasive rhythmic stimulation of the human brain.

    Science.gov (United States)

    Thut, Gregor; Schyns, Philippe G; Gross, Joachim

    2011-01-01

    The notion of driving brain oscillations by directly stimulating neuronal elements with rhythmic stimulation protocols has become increasingly popular in research on brain rhythms. Induction of brain oscillations in a controlled and functionally meaningful way would likely prove highly beneficial for the study of brain oscillations, and their therapeutic control. We here review conventional and new non-invasive brain stimulation protocols as to their suitability for controlled intervention into human brain oscillations. We focus on one such type of intervention, the direct entrainment of brain oscillations by a periodic external drive. We review highlights of the literature on entraining brain rhythms linked to perception and attention, and point out controversies. Behaviourally, such entrainment seems to alter specific aspects of perception depending on the frequency of stimulation, informing models on the functional role of oscillatory activity. This indicates that human brain oscillations and function may be promoted in a controlled way by focal entrainment, with great potential for probing into brain oscillations and their causal role.

  16. The neuroethics of non-invasive brain stimulation.

    Science.gov (United States)

    Cohen Kadosh, Roi; Levy, Neil; O'Shea, Jacinta; Shea, Nicholas; Savulescu, Julian

    2012-02-21

    Transcranial direct current stimulation (TDCS) is a brain stimulation tool that is portable, painless, inexpensive, apparently safe, and with potential long-term efficacy. Recent results obtained from TDCS experiments offer exciting possibilities for the enhancement and treatment of normal or impaired abilities, respectively. We discuss new neuroethical problems that have emerged from the usage of TDCS, and also focus on one of the most likely future applications of TDCS: enhancing learning and cognition in children with typical and atypical development.

  17. Ethical brain stimulation - neuroethics of deep brain stimulation in research and clinical practice.

    Science.gov (United States)

    Clausen, Jens

    2010-10-01

    Deep brain stimulation (DBS) is a clinically established procedure for treating severe motor symptoms in patients suffering from end-stage Parkinson's disease, dystonia and essential tremor. Currently, it is tested for further indications including psychiatric disorders like major depression and a variety of other diseases. However, ethical issues of DBS demand continuing discussion. Analysing neuroethical and clinical literature, five major topics concerning the ethics of DBS in clinical practice were identified: thorough examination and weighing of risks and benefits; selecting patients fairly; protecting the health of children in paediatric DBS; special issues concerning patients' autonomy; and the normative impact of quality of life measurements. In exploring DBS for further applications, additionally, issues of research ethics have to be considered. Of special importance in this context are questions such as what additional value is generated by the research, how to realise scientific validity, which patients should be included, and how to achieve an acceptable risk-benefit ratio. Patients' benefit is central for ethical evaluation. This criterion can outweigh very serious side-effects, and can make DBS appropriate even in paediatrics. Because standard test procedures evade central aspects of patients' benefits, measuring quality of life should be supplemented by open in-depth interviews to provide a more adequate picture of patients' post-surgical situation. To examine its entire therapeutic potential, further research in DBS is needed. Studies should be based on solid scientific hypotheses and proceed cautiously to benefit severely suffering patients without putting them to undue risks.

  18. Fornix deep brain stimulation enhances acetylcholine levels in the hippocampus

    OpenAIRE

    2015-01-01

    Deep brain stimulation (DBS) of the fornix has gained interest as a potential therapy for advanced treatment-resistant dementia, yet the mechanism of action remains widely unknown. Previously, we have reported beneficial memory effects of fornix DBS in a scopolamine-induced rat model of dementia, which is dependent on various brain structures including hippocampus. To elucidate mechanisms of action of fornix DBS with regard to memory restoration, we performed c-Fos immunohistochemistry in the...

  19. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

    OpenAIRE

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi...

  20. Imaging artifacts induced by electrical stimulation during conventional fMRI of the brain.

    Science.gov (United States)

    Antal, Andrea; Bikson, Marom; Datta, Abhishek; Lafon, Belen; Dechent, Peter; Parra, Lucas C; Paulus, Walter

    2014-01-15

    Functional magnetic resonance imaging (fMRI) of brain activation during transcranial electrical stimulation is used to provide insight into the mechanisms of neuromodulation and targeting of particular brain structures. However, the passage of current through the body may interfere with the concurrent detection of blood oxygen level-dependent (BOLD) signal, which is sensitive to local magnetic fields. To test whether these currents can affect concurrent fMRI recordings we performed conventional gradient echo-planar imaging (EPI) during transcranial direct current (tDCS) and alternating current stimulation (tACS) on two post-mortem subjects. tDCS induced signals in both superficial and deep structures. The signal was specific to the electrode montage, with the strongest signal near cerebrospinal fluid (CSF) and scalp. The direction of change relative to non-stimulation reversed with tDCS stimulation polarity. For tACS there was no net effect of the MRI signal. High-resolution individualized modeling of current flow and induced static magnetic fields suggested a strong coincidence of the change EPI signal with regions of large current density and magnetic fields. These initial results indicate that (1) fMRI studies of tDCS must consider this potentially confounding interference from current flow and (2) conventional MRI imaging protocols can be potentially used to measure current flow during transcranial electrical stimulation. The optimization of current measurement and artifact correction techniques, including consideration of the underlying physics, remains to be addressed.

  1. Introduction to the programming of deep brain stimulators.

    Science.gov (United States)

    Volkmann, Jens; Herzog, Jan; Kopper, Florian; Deuschl, Güntner

    2002-01-01

    The clinical success of deep brain stimulation (DBS) for treating Parkinson's disease, tremor, or dystonia critically depends on the quality of postoperative neurologic management. Movement disorder specialists becoming involved with this therapy need to acquire new skills to optimally adapt stimulation parameters and medication after implantation of a DBS system. In clinical practice, the infinite number of possible parameter settings in DBS can be reduced to few relevant combinations. In this article, the authors describe a general scheme of selecting stimulation parameters in DBS and provide clinical and neurophysiological arguments for such a standardized algorithm. They also describe noninvasive technical trouble shooting by using programming features of the commercially available neurostimulation devices.

  2. Transcranial magnetic stimulation: Improved coil design for deep brain investigation

    Science.gov (United States)

    Crowther, L. J.; Marketos, P.; Williams, P. I.; Melikhov, Y.; Jiles, D. C.; Starzewski, J. H.

    2011-04-01

    This paper reports on a design for a coil for transcranial magnetic stimulation. The design shows potential for improving the penetration depth of the magnetic field, allowing stimulation of subcortical structures within the brain. The magnetic and induced electric fields in the human head have been calculated with finite element electromagnetic modeling software and compared with empirical measurements. Results show that the coil design used gives improved penetration depth, but also indicates the likelihood of stimulation of additional tissue resulting from the spatial distribution of the magnetic field.

  3. Response to Deep Brain Stimulation in Three Brain Targets with Implications in Mental Disorders: A PET Study in Rats

    Science.gov (United States)

    Casquero-Veiga, Marta; Hadar, Ravit; Pascau, Javier; Winter, Christine; Desco, Manuel; Soto-Montenegro, María Luisa

    2016-01-01

    Objective To investigate metabolic changes in brain networks by deep brain stimulation (DBS) of the medial prefrontal cortex (mPFC), nucleus accumbens (NAcc) and dorsomedial thalamus (DM) using positron emission tomography (PET) in naïve rats. Methods 43 male Wistar rats underwent stereotactic surgery and concentric bipolar platinum-iridium electrodes were bilaterally implanted into one of the three brain sites. [18F]-fluoro-2-deoxy-glucose-PET (18FDG-PET) and computed tomography (CT) scans were performed at the 7th (without DBS) and 9th day (with DBS) after surgery. Stimulation period matched tracer uptake period. Images were acquired with a small-animal PET-CT scanner. Differences in glucose uptake between groups were assessed with Statistical Parametric Mapping. Results DBS induced site-specific metabolic changes, although a common increased metabolic activity in the piriform cortex was found for the three brain targets. mPFC-DBS increased metabolic activity in the striatum, temporal and amygdala, and reduced it in the cerebellum, brainstem (BS) and periaqueductal gray matter (PAG). NAcc-DBS increased metabolic activity in the subiculum and olfactory bulb, and decreased it in the BS, PAG, septum and hypothalamus. DM-DBS increased metabolic activity in the striatum, NAcc and thalamus and decreased it in the temporal and cingulate cortex. Conclusions DBS induced significant changes in 18FDG uptake in brain regions associated with the basal ganglia-thalamo-cortical circuitry. Stimulation of mPFC, NAcc and DM induced different patterns of 18FDG uptake despite interacting with the same circuitries. This may have important implications to DBS research suggesting individualized target selection according to specific neural modulatory requirements. PMID:28033356

  4. Effects of electrode configuration and geometry on fiber preference in spinal cord stimulation

    NARCIS (Netherlands)

    Holsheimer, Jan; Struijk, Johannes J.; Wesselink, Wilbert A.

    1996-01-01

    In contrast to the widespread assumption that dorsal column fibers are the primary targets of spinal cord stimulation by a dorsal epidural electrode, it appears that dorsal root fibers are recruited as well, and even preferentially under various conditions. This will, however, limit the coverage of

  5. Respiratory responses to stimulation of abdominal and upper-thorax intercostal muscles using multiple Permaloc electrodes.

    Science.gov (United States)

    Walter, James S; Thomas, Donald; Sayers, Scott; Perez-Tamayo, R Anthony; Crish, Timothy; Singh, Sanjay

    2015-01-01

    Stimulation of abdominal and upper-thoracic muscles was studied with the long-term goal of improved respiratory care for spinal cord injury (SCI) patients. A 12-channel stimulator and multiple surface and implanted Permaloc electrodes were evaluated in five anesthetized canines. Abdominal stimulation with 100 mA using four bilateral sets of surface electrodes placed on the midaxillary line at the 7th through 13th intercostal spaces and with a closed airway at a large lung volume produced an expiratory tracheal pressure of 109 +/- 29 cm H2O (n = 2, mean +/- standard error of the mean). Similar high pressures were induced with implanted electrodes at the same locations. Upper-thoracic stimulation with 40 mA and four sets of implanted electrodes ventral to the axilla induced inspiratory pressures of -12 +/- 2 cm H2O (n = 5). Combined extradiaphragmatic pacing with an open airway produced a tidal volume of 440 +/- 45 mL (n = 4). The robust respiratory volumes and pressures suggest applications in SCI respiratory care.

  6. Role of sound stimulation in reprogramming brain connectivity

    Indian Academy of Sciences (India)

    Sraboni Chaudhury; Tapas C Nag; Suman Jain; Shashi Wadhwa

    2013-09-01

    Sensory stimulation has a critical role to play in the development of an individual. Environmental factors tend to modify the inputs received by the sensory pathway. The developing brain is most vulnerable to these alterations and interacts with the environment to modify its neural circuitry. In addition to other sensory stimuli, auditory stimulation can also act as external stimuli to provide enrichment during the perinatal period. There is evidence that suggests that enriched environment in the form of auditory stimulation can play a substantial role in modulating plasticity during the prenatal period. This review focuses on the emerging role of prenatal auditory stimulation in the development of higher brain functions such as learning and memory in birds and mammals. The molecular mechanisms of various changes in the hippocampus following sound stimulation to effect neurogenesis, learning and memory are described. Sound stimulation can also modify neural connectivity in the early postnatal life to enhance higher cognitive function or even repair the secondary damages in various neurological and psychiatric disorders. Thus, it becomes imperative to examine in detail the possible ameliorating effects of prenatal sound stimulation in existing animal models of various psychiatric disorders, such as autism.

  7. Image-guided preoperative prediction of pyramidal tract side effect in deep brain stimulation

    Science.gov (United States)

    Baumgarten, C.; Zhao, Y.; Sauleau, P.; Malrain, C.; Jannin, P.; Haegelen, C.

    2016-03-01

    Deep brain stimulation of the medial globus pallidus is a surgical procedure for treating patients suffering from Parkinson's disease. Its therapeutic effect may be limited by the presence of pyramidal tract side effect (PTSE). PTSE is a contraction time-locked to the stimulation when the current spreading reaches the motor fibers of the pyramidal tract within the internal capsule. The lack of side-effect predictive model leads the neurologist to secure an optimal electrode placement by iterating clinical testing on an awake patient during the surgical procedure. The objective of the study was to propose a preoperative predictive model of PTSE. A machine learning based method called PyMAN (for Pyramidal tract side effect Model based on Artificial Neural network) that accounted for the current of the stimulation, the 3D electrode coordinates and the angle of the trajectory, was designed to predict the occurrence of PTSE. Ten patients implanted in the medial globus pallidus have been tested by a clinician to create a labeled dataset of the stimulation parameters that trigger PTSE. The kappa index value between the data predicted by PyMAN and the labeled data was .78. Further evaluation studies are desirable to confirm whether PyMAN could be a reliable tool for assisting the surgeon to prevent PTSE during the preoperative planning.

  8. Non-invasive brain stimulation in neglect rehabilitation: An update.

    Directory of Open Access Journals (Sweden)

    René Martin Müri

    2013-06-01

    Full Text Available Here, we review the effects of non-invasive brain stimulation (NIBS such as transcranial magnetic stimulation (TMS or transcranial direct current stimulation (tDCS in the rehabilitation of neglect. We found 12 studies including 172 patients (10 TMS studies and 2 tDCS studies fulfilling our search criteria. Activity of daily living (ADL measures such as the Barthel Index or more specifically for neglect, the Catherine Bergego Scale were the outcome measure in 3 studies. Five studies were randomized controlled trials with a follow-up time after intervention of up to 6 weeks. One TMS study fulfilled criteria for Class I and one for Class III evidence.The studies are heterogeneous concerning their methodology, outcome measures, and stimulation parameters making firm comparisons and conclusions difficult. Overall, there are however promising results for theta burst stimulation, suggesting that TMS is a powerful add-on therapy in the rehabilitation of neglect patients.

  9. Non-invasive brain stimulation in neglect rehabilitation: an update.

    Science.gov (United States)

    Müri, René Martin; Cazzoli, Dario; Nef, Tobias; Mosimann, Urs P; Hopfner, Simone; Nyffeler, Thomas

    2013-01-01

    Here, we review the effects of non-invasive brain stimulation such as transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) in the rehabilitation of neglect. We found 12 studies including 172 patients (10 TMS studies and 2 tDCS studies) fulfilling our search criteria. Activity of daily living measures such as the Barthel Index or, more specifically for neglect, the Catherine Bergego Scale were the outcome measure in three studies. Five studies were randomized controlled trials with a follow-up time after intervention of up to 6 weeks. One TMS study fulfilled criteria for Class I and one for Class III evidence. The studies are heterogeneous concerning their methodology, outcome measures, and stimulation parameters making firm comparisons and conclusions difficult. Overall, there are however promising results for theta-burst stimulation, suggesting that TMS is a powerful add-on therapy in the rehabilitation of neglect patients.

  10. Situating the self: understanding the effects of deep brain stimulation

    NARCIS (Netherlands)

    Dings, R.P.J.M.; Bruin, L.C. de

    2015-01-01

    The article proposes a theoretical model to account for changes in self due to Deep Brain Stimulation (DBS). First, we argue that most existing models postulate a very narrow conception of self, and thus fail to capture the full range of potentially relevant DBS-induced changes. Second, building on

  11. Deep brain stimulation for dystonia : Patient selection and outcomes

    NARCIS (Netherlands)

    Speelman, J. D.; Contarino, M. F.; Schuurman, P. R.; Tijssen, M. A. J.; de Bie, R. M. A.

    2010-01-01

    In a literature survey, 341 patients with primary and 109 with secondary dystonias treated with deep brain stimulation (DBS) of the internal segment of the globus pallidus (GPi) were identified. In general, the outcomes for primary dystonias were more favourable compared to the secondary forms. For

  12. Models to Tailor Brain Stimulation Therapies in Stroke

    Directory of Open Access Journals (Sweden)

    E. B. Plow

    2016-01-01

    Full Text Available A great challenge facing stroke rehabilitation is the lack of information on how to derive targeted therapies. As such, techniques once considered promising, such as brain stimulation, have demonstrated mixed efficacy across heterogeneous samples in clinical studies. Here, we explain reasons, citing its one-type-suits-all approach as the primary cause of variable efficacy. We present evidence supporting the role of alternate substrates, which can be targeted instead in patients with greater damage and deficit. Building on this groundwork, this review will also discuss different frameworks on how to tailor brain stimulation therapies. To the best of our knowledge, our report is the first instance that enumerates and compares across theoretical models from upper limb recovery and conditions like aphasia and depression. Here, we explain how different models capture heterogeneity across patients and how they can be used to predict which patients would best respond to what treatments to develop targeted, individualized brain stimulation therapies. Our intent is to weigh pros and cons of testing each type of model so brain stimulation is successfully tailored to maximize upper limb recovery in stroke.

  13. [Non-invasive brain stimulation for Parkinson's disease].

    Science.gov (United States)

    Gajo, Gianandrea; Pollak, Pierre; Lüscher, Christian; Benninger, David

    2015-04-29

    Parkinson's disease (PD) is a major socio-economic burden increasing with the aging population. In advanced PD, the emergence of symptoms refractory to conventional therapy poses a therapeutic challenge. The success of deep brain stimulation (DBS) and advances in the understanding of the pathophysiology of PD have raised interest in non-invasive brain stimulation (NIBS) as an alternative therapeutic tool. NIBS could offer an alternative approach for patients at risk who are excluded from surgery and/or to treat refractory symptoms. The treatment of the freezing of gait, a major cause of disability and falls in PD patients, could be enhanced by transcranial direct current stimulation (tDCS). A therapeutic study is currently performed at the Department of Neurology at the CHUV.

  14. Moral Enhancement Using Non-invasive Brain Stimulation

    Science.gov (United States)

    Darby, R. Ryan; Pascual-Leone, Alvaro

    2017-01-01

    Biomedical enhancement refers to the use of biomedical interventions to improve capacities beyond normal, rather than to treat deficiencies due to diseases. Enhancement can target physical or cognitive capacities, but also complex human behaviors such as morality. However, the complexity of normal moral behavior makes it unlikely that morality is a single capacity that can be deficient or enhanced. Instead, our central hypothesis will be that moral behavior results from multiple, interacting cognitive-affective networks in the brain. First, we will test this hypothesis by reviewing evidence for modulation of moral behavior using non-invasive brain stimulation. Next, we will discuss how this evidence affects ethical issues related to the use of moral enhancement. We end with the conclusion that while brain stimulation has the potential to alter moral behavior, such alteration is unlikely to improve moral behavior in all situations, and may even lead to less morally desirable behavior in some instances. PMID:28275345

  15. Interdigitated array of Pt electrodes for electrical stimulation and engineering of aligned muscle tissue.

    Science.gov (United States)

    Ahadian, Samad; Ramón-Azcón, Javier; Ostrovidov, Serge; Camci-Unal, Gulden; Hosseini, Vahid; Kaji, Hirokazu; Ino, Kosuke; Shiku, Hitoshi; Khademhosseini, Ali; Matsue, Tomokazu

    2012-09-21

    Engineered skeletal muscle tissues could be useful for applications in tissue engineering, drug screening, and bio-robotics. It is well-known that skeletal muscle cells are able to differentiate under electrical stimulation (ES), with an increase in myosin production, along with the formation of myofibers and contractile proteins. In this study, we describe the use of an interdigitated array of electrodes as a novel platform to electrically stimulate engineered muscle tissues. The resulting muscle myofibers were analyzed and quantified in terms of their myotube characteristics and gene expression. The engineered muscle tissues stimulated through the interdigitated array of electrodes demonstrated superior performance and maturation compared to the corresponding tissues stimulated through a conventional setup (i.e., through Pt wires in close proximity to the muscle tissue). In particular, the ES of muscle tissue (voltage 6 V, frequency 1 Hz and duration 10 ms for 1 day) through the interdigitated array of electrodes resulted in a higher degree of C2C12 myotube alignment (∼80%) as compared to ES using Pt wires (∼65%). In addition, higher amounts of C2C12 myotube coverage area, myotube length, muscle transcription factors and protein biomarkers were found for myotubes stimulated through the interdigitated array of electrodes compared to those stimulated using the Pt wires. Due to the wide array of potential applications of ES for two- and three-dimensional (2D and 3D) engineered tissues, the suggested platform could be employed for a variety of cell and tissue structures to more efficiently investigate their response to electrical fields.

  16. Performance of dry electrode with bristle in recording EEG rhythms across brain state changes.

    Science.gov (United States)

    Kitoko, Vangu; Nguyen, Tuan N; Nguyen, Jordan S; Tran, Yvonne; Nguyen, Hung T

    2011-01-01

    In this paper we evaluate the physiological performance of a silver-silver chloride dry electrode with bristle (B-Electrode) in recording EEG data. For this purpose, we compare the performance of the bristle electrode in recording EEG data with the standard wet gold-plated cup electrode (G-Electrode) using two different brain state change tasks including resting condition with eyes-closed and performing mathematical task with eyes-open. Using a 2 channel recording device, eyes-closed command data were collected from each of 6 participants for a period of 20 sec and the same procedure was applied for the mathematical calculation task. These data were used for statistical and classification analyse. Although, B-electrode has shown a slightly higher performance compared with G-electrode in both tasks, but analyse did not reveal any significant differences between both electrodes in all six subjects tested.

  17. Long-term follow-up study on the safety of deep brain stimulation for treating Parkinson's disease

    OpenAIRE

    Xi WU; Jian-chun CHEN; Wan-lu WANG; Hao, Bin; Chen, Xin; Xiao-wu HU

    2015-01-01

    Objective To evaluate the safety of deep brain stimulation (DBS) for treating Parkinson's disease (PD) under long-term follow-up and modify the surgical procedure. Methods A total of 362 PD patients underwent DBS, and almost 613 electrodes were implanted into these patients. Both surgical and hardware-related complications of DBS were retrospectively analyzed. Results Perioperative complications included postoperative confusion or delirium in 21 cases (5.80%), intracranial hemorrhage i...

  18. Effects of Anterior Thalamic Nucleus Deep Brain Stimulation in Chronic Epileptic Rats

    Science.gov (United States)

    Amorim, Beatriz; Cavarsan, Clarissa; Miranda, Maisa Ferreira; Aarão, Mayra C.; Madureira, Ana Paula; Rodrigues, Antônio M.; Nobrega, José N.; Mello, Luiz E.; Hamani, Clement

    2014-01-01

    Deep brain stimulation (DBS) has been investigated for the treatment of epilepsy. In rodents, an increase in the latency for the development of seizures and status epilepticus (SE) has been reported in different animal models but the consequences of delivering stimulation to chronic epileptic animals have not been extensively addressed. We study the effects of anterior thalamic nucleus (AN) stimulation at different current intensities in rats rendered epileptic following pilocarpine (Pilo) administration. Four months after Pilo-induced SE, chronic epileptic rats were bilaterally implanted with AN electrodes or had sham-surgery. Stimulation was delivered for 6 h/day, 5 days/week at 130 Hz, 90 µsec. and either 100 µA or 500 µA. The frequency of spontaneous recurrent seizures in animals receiving stimulation was compared to that recorded in the preoperative period and in rats given sham treatment. To investigate the effects of DBS on hippocampal excitability, brain slices from animals receiving AN DBS or sham surgery were studied with electrophysiology. We found that rats treated with AN DBS at 100 µA had a 52% non-significant reduction in the frequency of seizures as compared to sham-treated controls and 61% less seizures than at baseline. Animals given DBS at 500 µA had 5.1 times more seizures than controls and a 2.8 fold increase in seizure rate as compared to preoperative values. In non-stimulated controls, the average frequency of seizures before and after surgery remained unaltered. In vitro recordings have shown that slices from animals previously given DBS at 100 µA had a longer latency for the development of epileptiform activity, shorter and smaller DC shifts, and a smaller spike amplitude compared to non-stimulated controls. In contrast, a higher spike amplitude was recorded in slices from animals given AN DBS at 500 µA. PMID:24892420

  19. The neurophysiology of language: Insights from non-invasive brain stimulation in the healthy human brain.

    Science.gov (United States)

    Hartwigsen, Gesa

    2015-09-01

    With the advent of non-invasive brain stimulation (NIBS), a new decade in the study of language has started. NIBS allows for testing the functional relevance of language-related brain activation and enables the researcher to investigate how neural activation changes in response to focal perturbations. This review focuses on the application of NIBS in the healthy brain. First, some basic mechanisms will be introduced and the prerequisites for carrying out NIBS studies of language are addressed. The next section outlines how NIBS can be used to characterize the contribution of the stimulated area to a task. In this context, novel approaches such as multifocal transcranial magnetic stimulation and the condition-and-perturb approach are discussed. The third part addresses the combination of NIBS and neuroimaging in the study of plasticity. These approaches are particularly suited to investigate short-term reorganization in the healthy brain and may inform models of language recovery in post-stroke aphasia.

  20. A critical reflection on the technological development of deep brain stimulation (DBS

    Directory of Open Access Journals (Sweden)

    Christian eIneichen

    2014-09-01

    Full Text Available Since the translational research findings of Benabid and colleagues, which partly led to their seminal paper regarding the treatment of mainly tremor-dominant Parkinson patients through thalamic high-frequency-stimulation (HFS in 1987, we still struggle with identifying a satisfactory mechanistic explanation of the underlying principles of Deep Brain Stimulation. Furthermore, the technological advance of DBS devices (electrodes and implantable pulse generators, IPG's has shown a distinct lack of dynamic progression. In light of this we argue that it is time to leave the paleolithic age and enter hellenistic times: the device-manufacturing industry and the medical community together should put more emphasis on advancing the technology rather than resting on their laurels.

  1. Effects of electrode geometry and combination on nerve fibre selectivity in spinal cord stimulation.

    Science.gov (United States)

    Holsheimer, J; Struijk, J J; Tas, N R

    1995-09-01

    The differential effects of the geometry of a rostrocaudal array of electrode contacts on dorsal column fibre and dorsal root fibre activation in spinal cord stimulation are analysed theoretically. 3-D models of the mid-cervical and mid-thoracic vertebral areas are used for the computation of stimulation induced field potentials, whereas a cable model of myelinated nerve fibre is used for the calculation of the excitation thresholds of large dorsal column and dorsal root fibres. The size and spacing of 2-D rectangular electrode contacts are varied while mono-, bi- and tripolar stimulation are applied. The model predicts that the highest preferential stimulation of dorsal root fibres is obtained in monopolar stimulation with a large cathode, whereas dorsal column fibre preference is highest in tripolar stimulation with small contacts and small contact spacings. Fibre type preference is most sensitive to variations of rostrocaudal contact size and least sensitive to variations of lateral contact size. Dorsal root fibre preference is increased and sensitivity to lead geometry is reduced as the distance from contacts to spinal cord is increased.

  2. A new brain stimulation method: Noninvasive transcranial magneto-acoustical stimulation

    Science.gov (United States)

    Yuan, Yi; Chen, Yu-Dong; Li, Xiao-Li

    2016-08-01

    We investigate transcranial magneto-acoustical stimulation (TMAS) for noninvasive brain neuromodulation in vivo. TMAS as a novel technique uses an ultrasound wave to induce an electric current in the brain tissue in the static magnetic field. It has the advantage of high spatial resolution and penetration depth. The mechanism of TMAS onto a neuron is analyzed by combining the TMAS principle and Hodgkin-Huxley neuron model. The anesthetized rats are stimulated by TMAS, resulting in the local field potentials which are recorded and analyzed. The simulation results show that TMAS can induce neuronal action potential. The experimental results indicate that TMAS can not only increase the amplitude of local field potentials but also enhance the effect of focused ultrasound stimulation on the neuromodulation. In summary, TMAS can accomplish brain neuromodulation, suggesting a potentially powerful noninvasive stimulation method to interfere with brain rhythms for diagnostic and therapeutic purposes. Project supported by the National Natural Science Foundation of China (Grant Nos. 61503321 and 61273063) and the Natural Science Foundation of Hebei Province, China (Grant No. F2014203161).

  3. Reducing proactive aggression through non-invasive brain stimulation.

    Science.gov (United States)

    Dambacher, Franziska; Schuhmann, Teresa; Lobbestael, Jill; Arntz, Arnoud; Brugman, Suzanne; Sack, Alexander T

    2015-10-01

    Aggressive behavior poses a threat to human collaboration and social safety. It is of utmost importance to identify the functional mechanisms underlying aggression and to develop potential interventions capable of reducing dysfunctional aggressive behavior already at a brain level. We here experimentally shifted fronto-cortical asymmetry to manipulate the underlying motivational emotional states in both male and female participants while assessing the behavioral effects on proactive and reactive aggression. Thirty-two healthy volunteers received either anodal transcranial direct current stimulation to increase neural activity within right dorsolateral prefrontal cortex, or sham stimulation. Aggressive behavior was measured with the Taylor Aggression Paradigm. We revealed a general gender effect, showing that men displayed more behavioral aggression than women. After the induction of right fronto-hemispheric dominance, proactive aggression was reduced in men. This study demonstrates that non-invasive brain stimulation can reduce aggression in men. This is a relevant and promising step to better understand how cortical brain states connect to impulsive actions and to examine the causal role of the prefrontal cortex in aggression. Ultimately, such findings could help to examine whether the brain can be a direct target for potential supportive interventions in clinical settings dealing with overly aggressive patients and/or violent offenders.

  4. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    2013-01-01

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cer

  5. Network Theory and Effects of Transcranial Brain Stimulation Methods on the Brain Networks

    Directory of Open Access Journals (Sweden)

    Sema Demirci

    2014-12-01

    Full Text Available In recent years, there has been a shift from classic localizational approaches to new approaches where the brain is considered as a complex system. Therefore, there has been an increase in the number of studies involving collaborations with other areas of neurology in order to develop methods to understand the complex systems. One of the new approaches is graphic theory that has principles based on mathematics and physics. According to this theory, the functional-anatomical connections of the brain are defined as a network. Moreover, transcranial brain stimulation techniques are amongst the recent research and treatment methods that have been commonly used in recent years. Changes that occur as a result of applying brain stimulation techniques on physiological and pathological networks help better understand the normal and abnormal functions of the brain, especially when combined with techniques such as neuroimaging and electroencephalography. This review aims to provide an overview of the applications of graphic theory and related parameters, studies conducted on brain functions in neurology and neuroscience, and applications of brain stimulation systems in the changing treatment of brain network models and treatment of pathological networks defined on the basis of this theory.

  6. Effects of Deep Brain Stimulation on Autonomic Function

    Directory of Open Access Journals (Sweden)

    Adam Basiago

    2016-08-01

    Full Text Available Over the course of the development of deep brain stimulation (DBS into a well-established therapy for Parkinson’s disease, essential tremor, and dystonia, its utility as a potential treatment for autonomic dysfunction has emerged. Dysfunction of autonomic processes is common in neurological diseases. Depending on the specific target in the brain, DBS has been shown to raise or lower blood pressure, normalize the baroreflex, to alter the caliber of bronchioles, and eliminate hyperhidrosis, all through modulation of the sympathetic nervous system. It has also been shown to improve cortical control of the bladder, directly induce or inhibit the micturition reflex, and to improve deglutition and gastric emptying. In this review, we will attempt to summarize the relevant available studies describing these effects of DBS on autonomic function, which vary greatly in character and magnitude with respect to stimulation target.

  7. Effectiveness of diaphragmatic stimulation with single-channel electrodes in rabbits

    Directory of Open Access Journals (Sweden)

    Rodrigo Guellner Ghedini

    2013-06-01

    Full Text Available Every year, a large number of individuals become dependent on mechanical ventilation because of a loss of diaphragm function. The most common causes are cervical spinal trauma and neuromuscular diseases. We have developed an experimental model to evaluate the performance of electrical stimulation of the diaphragm in rabbits using single-channel electrodes implanted directly into the muscle. Various current intensities (10, 16, 20, and 26 mA produced tidal volumes above the baseline value, showing that this model is effective for the study of diaphragm performance at different levels of electrical stimulation

  8. Deep Brain Stimulation in Tourette’s Syndrome

    OpenAIRE

    Fraint, Avram; Pal, Gian

    2015-01-01

    Objective Tourette’s syndrome (TS) is defined by 1 year of persistent motor and vocal tics. Often, the tics are refractory to conventional pharmacologic and psychobehavioral interventions. In these patients, deep brain stimulation (DBS) may be an appropriate intervention. This paper reviews different DBS targets in TS, discusses existing evidence on the efficacy of DBS in TS, highlights adverse effects of the procedure, discusses indications and patient selection as well as future directio...

  9. Anomia training and brain stimulation in chronic aphasia.

    Science.gov (United States)

    Cotelli, Maria; Fertonani, Anna; Miozzo, Antonio; Rosini, Sandra; Manenti, Rosa; Padovani, Alessandro; Ansaldo, Ana Ines; Cappa, Stefano F; Miniussi, Carlo

    2011-10-01

    Recent studies have reported enhanced performance on language tasks induced by non-invasive brain stimulation, i.e., repetitive transcranial magnetic stimulation (rTMS), or transcranial direct current stimulation (tDCS), in patients with aphasia due to stroke or Alzheimer's disease (AD). The first part of this article reviews brain stimulation studies related to language recovery in aphasic patients. The second part reports results from a pilot study with three chronic stroke patients who had non-fluent aphasia, where real or placebo rTMS was immediately followed by 25 minutes of individualised speech therapy. Real rTMS consisted of high-frequency rTMS over the left dorsolateral prefrontal cortex (BA 8/9) for 25 minutes. Each patient underwent a total of four weeks of intervention. P1 underwent four weeks of real rTMS (5 days/week) where individualised speech therapy was provided for 25 minutes immediately following each rTMS session. P2 and P3 each underwent two weeks of placebo rTMS, followed immediately by individualised speech therapy; then two weeks of real rTMS, followed immediately by individualised speech therapy. Assessments took place at 2, 4, 12, 24 and 48 weeks post-entry/baseline testing. Relative to entry/baseline testing, a significant improvement in object naming was observed at all testing times, from two weeks post-intervention in real rTMS plus speech therapy, or placebo rTMS plus speech therapy. Our findings suggest beneficial effects of targeted behavioural training in combination with brain stimulation in chronic aphasic patients. However, further work is required in order to verify whether optimal combination parameters (rTMS alone or speech therapy alone) and length of rTMS treatment may be found.

  10. Modulation of brain dead induced inflammation by vagus nerve stimulation.

    Science.gov (United States)

    Hoeger, S; Bergstraesser, C; Selhorst, J; Fontana, J; Birck, R; Waldherr, R; Beck, G; Sticht, C; Seelen, M A; van Son, W J; Leuvenink, H; Ploeg, R; Schnuelle, P; Yard, B A

    2010-03-01

    Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip-analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFalpha concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFalpha concentrations and resulted in down-regulation of a multiplicity of pro-inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E-selectin, IL1beta and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFalpha through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

  11. Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

    Science.gov (United States)

    Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

    2011-07-01

    Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here.

  12. The rationale for deep brain stimulation in Alzheimer's disease.

    Science.gov (United States)

    Mirzadeh, Zaman; Bari, Ausaf; Lozano, Andres M

    2016-07-01

    Alzheimer's disease is a major worldwide health problem with no effective therapy. Deep brain stimulation (DBS) has emerged as a useful therapy for certain movement disorders and is increasingly being investigated for treatment of other neural circuit disorders. Here we review the rationale for investigating DBS as a therapy for Alzheimer's disease. Phase I clinical trials of DBS targeting memory circuits in Alzheimer's disease patients have shown promising results in clinical assessments of cognitive function, neurophysiological tests of cortical glucose metabolism, and neuroanatomical volumetric measurements showing reduced rates of atrophy. These findings have been supported by animal studies, where electrical stimulation of multiple nodes within the memory circuit have shown neuroplasticity through stimulation-enhanced hippocampal neurogenesis and improved performance in memory tasks. The precise mechanisms by which DBS may enhance memory and cognitive functions in Alzheimer's disease patients and the degree of its clinical efficacy continue to be examined in ongoing clinical trials.

  13. Deep brain stimulation for movement disorders: update on recent discoveries and outlook on future developments.

    Science.gov (United States)

    Mahlknecht, Philipp; Limousin, Patricia; Foltynie, Thomas

    2015-11-01

    Modern deep brain stimulation (DBS) has become a routine therapy for patients with movement disorders such as Parkinson's disease, generalized or segmental dystonia and for multiple forms of tremor. Growing numbers of publications also report beneficial effects in other movement disorders such as Tourette's syndrome, various forms of chorea and DBS is even being studied for Parkinson's-related dementia. While exerting remarkable effects on many motor symptoms, DBS does not restore normal neurophysiology and therefore may also have undesirable side effects including speech and gait deterioration. Furthermore, its efficacy might be compromised in the long term, due to progression of the underlying disease. Various programming strategies have been studied to try and address these issues, e.g., the use of low-frequency rather than high-frequency stimulation or the targeting of alternative brain structures such as the pedunculopontine nucleus. In addition, further technical developments will soon provide clinicians with an expanded choice of hardware such as segmented electrodes allowing for a steering of the current to optimize beneficial effects and reduce side effects as well as the possibility of adaptive stimulation systems based on closed-loop concepts with or without accompanying advances in programming and imaging software. In the present article, we will provide an update on the most recent achievements and discoveries relevant to the application of DBS in the treatment of movement disorder patients and give an outlook on future clinical and technical developments.

  14. [Chronic high frequency deep brain stimulation of the globus pallidus internus for torsion dystonia].

    Science.gov (United States)

    Vesper, J; Klostermann, F; Funk, T; Bock, M

    2002-01-01

    Deep Brain Stimulation (DBS, chronic high frequency stimulation) is well established for Parkinson's disease and tremordominant movement disorders. Generalized dystonia is known as a type of movement disorder in which therapeutic options are very limited. A case of generalized dystonia is reported which was successfully treated by DBS in the Globus pallidus internus (GPI). A 26 years old male suffered from severe torsion dystonia of the lower limbs. The onset of symptoms was at age 7. It started with dystonia of the left foot. He very fast developed severe dystonia of the lower limbs. These complaints were initially treated by diazepam, later by baclofen (Lioresal ((R))) p.o em leader There was no L-DOPA response. Because of the rapid progression of the disease a cervical spinal cord stimulator was implanted with a transient success. Due to further progression of the disease the patient became wheelchair bounded and resistant for oral medication. Limited improvement of symptoms was achieved using continuous intrathecal administration of baclofen. Finally the patient was treated with 980 microgram intrathecal Baclofen (Lioresal ((R))) daily and up to 100 mg diazepam. Under these conditions the patient remained wheelchair bounded with severe lower limb dystonia. As an ultima ratio it was decided to treat the patient with stereotactic implantation of two electrodes (Medtronic 3387) and two neurostimulators (Medtronic ITREL ((R))II). The GPI was the bilateral target point. Intraoperative computerized tomography and ventriculography were used for target setting. Furthermore microrecordings were helpful to ensure the exact electrode positioning. Surgery was performed under sedation. Two weeks after surgery first improvement of symptoms was observed. Patient was able to stand with assistance. At the three months follow-up he could walk without assistance. Slight dystonic movement of the left ankle was the only remaining symptom under stimulation. The oral medication has

  15. Transcranial brain stimulation to promote functional recovery after stroke

    DEFF Research Database (Denmark)

    Raffin, Estelle; Siebner, Hartwig R

    2014-01-01

    PURPOSE OF REVIEW: Noninvasive brain stimulation (NIBS) is increasingly used to enhance the recovery of function after stroke. The purpose of this review is to highlight and discuss some unresolved questions that need to be addressed to better understand and exploit the potential of NIBS...... therapeutic efficacy. SUMMARY: This review addressed six questions: How does NIBS facilitate the recovery of function after stroke? Which brain regions should be targeted by NIBS? Is there a particularly effective NIBS modality that should be used? Does the location of the stroke influence the therapeutic...... response? How often should NIBS be repeated? Is the functional state of the brain during or before NIBS relevant to therapeutic efficacy of NIBS? We argue that these questions need to be tackled to obtain sufficient mechanistic understanding of how NIBS facilitates the recovery of function. This knowledge...

  16. Vertical electric field stimulated neural cell functionality on porous amorphous carbon electrodes.

    Science.gov (United States)

    Jain, Shilpee; Sharma, Ashutosh; Basu, Bikramjit

    2013-12-01

    We demonstrate the efficacy of amorphous macroporous carbon substrates as electrodes to support neuronal cell proliferation and differentiation in electric field mediated culture conditions. The electric field was applied perpendicular to carbon substrate electrode, while growing mouse neuroblastoma (N2a) cells in vitro. The placement of the second electrode outside of the cell culture medium allows the investigation of cell response to electric field without the concurrent complexities of submerged electrodes such as potentially toxic electrode reactions, electro-kinetic flows and charge transfer (electrical current) in the cell medium. The macroporous carbon electrodes are uniquely characterized by a higher specific charge storage capacity (0.2 mC/cm(2)) and low impedance (3.3 kΩ at 1 kHz). The optimal window of electric field stimulation for better cell viability and neurite outgrowth is established. When a uniform or a gradient electric field was applied perpendicular to the amorphous carbon substrate, it was found that the N2a cell viability and neurite length were higher at low electric field strengths (≤ 2.5 V/cm) compared to that measured without an applied field (0 V/cm). While the cell viability was assessed by two complementary biochemical assays (MTT and LDH), the differentiation was studied by indirect immunostaining. Overall, the results of the present study unambiguously establish the uniform/gradient vertical electric field based culture protocol to either enhance or to restrict neurite outgrowth respectively at lower or higher field strengths, when neuroblastoma cells are cultured on porous glassy carbon electrodes having a desired combination of electrochemical properties.

  17. Optimal control of directional deep brain stimulation in the parkinsonian neuronal network

    Science.gov (United States)

    Fan, Denggui; Wang, Zhihui; Wang, Qingyun

    2016-07-01

    The effect of conventional deep brain stimulation (DBS) on debilitating symptoms of Parkinson's disease can be limited because it can only yield the spherical field. And, some side effects are clearly induced with influencing their adjacent ganglia. Recent experimental evidence for patients with Parkinson's disease has shown that a novel DBS electrode with 32 independent stimulation source contacts can effectively optimize the clinical therapy by enlarging the therapeutic windows, when it is applied on the subthalamic nucleus (STN). This is due to the selective activation in clusters of various stimulation contacts which can be steered directionally and accurately on the targeted regions of interest. In addition, because of the serious damage to the neural tissues, the charge-unbalanced stimulation is not typically indicated and the real DBS utilizes charge-balanced bi-phasic (CBBP) pulses. Inspired by this, we computationally investigate the optimal control of directional CBBP-DBS from the proposed parkinsonian neuronal network of basal ganglia-thalamocortical circuit. By appropriately tuning stimulation for different neuronal populations, it can be found that directional steering CBBP-DBS paradigms are superior to the spherical case in improving parkinsonian dynamical properties including the synchronization of neuronal populations and the reliability of thalamus relaying the information from cortex, which is in a good agreement with the physiological experiments. Furthermore, it can be found that directional steering stimulations can increase the optimal stimulation intensity of desynchronization by more than 1 mA compared to the spherical case. This is consistent with the experimental result with showing that there exists at least one steering direction that can allow increasing the threshold of side effects by 1 mA. In addition, we also simulate the local field potential (LFP) and dominant frequency (DF) of the STN neuronal population induced by the activation

  18. Post-operative assessment in Deep Brain Stimulation based on multimodal images: registration workflow and validation

    Science.gov (United States)

    Lalys, Florent; Haegelen, Claire; Abadie, Alexandre; Jannin, Pierre

    2009-02-01

    Object Movement disorders in Parkinson disease patients may require functional surgery, when medical therapy isn't effective. In Deep Brain Stimulation (DBS) electrodes are implanted within the brain to stimulate deep structures such as SubThalamic Nucleus (STN). This paper describes successive steps for constructing a digital Atlas gathering patient's location of electrodes and contacts for post operative assessment. Materials and Method 12 patients who had undergone bilateral STN DBS have participated to the study. Contacts on post-operative CT scans were automatically localized, based on black artefacts. For each patient, post operative CT images were rigidly registered to pre operative MR images. Then, pre operative MR images were registered to a MR template (super-resolution Collin27 average MRI template). This last registration was the combination of global affine, local affine and local non linear registrations, respectively. Four different studies were performed in order to validate the MR patient to template registration process, based on anatomical landmarks and clinical scores (i.e., Unified Parkinson's disease rating Scale). Visualisation software was developed for displaying into the template images the stimulated contacts represented as cylinders with a colour code related to the improvement of the UPDRS. Results The automatic contact localization algorithm was successful for all the patients. Validation studies for the registration process gave a placement error of 1.4 +/- 0.2 mm and coherence with UPDRS scores. Conclusion The developed visualization tool allows post-operative assessment for previous interventions. Correlation with additional clinical scores will certainly permit to learn more about DBS and to better understand clinical side-effects.

  19. Non invasive brain stimulation to enhance post-stroke recovery

    Directory of Open Access Journals (Sweden)

    Nathalie Kubis

    2016-07-01

    Full Text Available Brain plasticity after stroke remains poorly understood. Patients may improve spontaneously within the first 3 months and then more slowly in the coming year. The first days, decreased edema and reperfusion of the ischemic penumbra may possibly account for these phenomena, but the improvement during the next weeks suggests plasticity phenomena and cortical reorganization of the brain ischemic areas and of more remote areas. Indeed, the injured ischemic motor cortex has a reduced cortical excitability at the acute phase and a suspension of the topographic representation of affected muscles, whereas the contralateral motor cortex has an increased excitability and an enlarged somatomotor representation; furthermore, contralateral cortex exerts a transcallosal interhemispheric inhibition on the ischemic cortex. This results from the imbalance of the physiological reciprocal interhemispheric inhibition of each hemisphere on the other, contributing to worsening of neurological deficit. Cortical excitability is measurable through transcranial magnetic stimulation (TMS and prognosis has been established according to the presence of motor evoked potentials (MEP at the acute phase of stroke, which is predictive of better recovery. Conversely, the lack of response to early stimulation is associated with a poor functional outcome. Non-invasive stimulation techniques such as repetitive TMS (rTMS or transcranial direct current stimulation (tDCS have the potential to modulate brain cortical excitability with long lasting effects. In the setting of cerebrovascular disease, around 1000 stroke subjects have been included in placebo-controlled trials so far, most often with an objective of promoting motor recovery of the upper limb. High frequency repetitive stimulation (> 3 Hz rTMS, aiming to increase excitability of the ischemic cortex, or low frequency repetitive stimulation (≤ 1 Hz, aiming to reduce excitability of the contralateral homonymous cortex, or

  20. Electrodic voltages accompanying stimulated bioremediation of a uranium-contaminated aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.H.; N' Guessan, A.L.; Druhan, J.; Long, P.E.; Hubbard, S.S.; Lovley, D.R.; Banfield, J.F.

    2009-11-15

    The inability to track the products of subsurface microbial activity during stimulated bioremediation has limited its implementation. We used spatiotemporal changes in electrodic potentials (EP) to track the onset and persistence of stimulated sulfate-reducing bacteria in a uranium-contaminated aquifer undergoing acetate amendment. Following acetate injection, anomalous voltages approaching -900 mV were measured between copper electrodes within the aquifer sediments and a single reference electrode at the ground surface. Onset of EP anomalies correlated in time with both the accumulation of dissolved sulfide and the removal of uranium from groundwater. The anomalies persisted for 45 days after halting acetate injection. Current-voltage and current-power relationships between measurement and reference electrodes exhibited a galvanic response, with a maximum power density of 10 mW/m{sup 2} during sulfate reduction. We infer that the EP anomalies resulted from electrochemical differences between geochemically reduced regions and areas having higher oxidation potential. Following the period of sulfate reduction, EP values ranged from -500 to -600 mV and were associated with elevated concentrations of ferrous iron. Within 10 days of the voltage decrease, uranium concentrations rebounded from 0.2 to 0.8 {mu}M, a level still below the background value of 1.5 {mu}M. These findings demonstrate that EP measurements provide an inexpensive and minimally invasive means for monitoring the products of stimulated microbial activity within aquifer sediments and are capable of verifying maintenance of redox conditions favorable for the stability of bioreduced contaminants, such as uranium.

  1. Detection of spreading depolarization with intraparenchymal electrodes in the injured human brain

    DEFF Research Database (Denmark)

    Jeffcote, Toby; Hinzman, Jason M; Jewell, Sharon L

    2014-01-01

    BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can ...... for craniotomy. The method provides a new investigative tool for the evaluation of the contribution of these events to secondary brain injury in human patients.......BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can...... for traumatic brain injury or aneurysmal subarachnoid hemorrhage were monitored for depolarization events in an intensive care setting with concurrent strip (subdural) and depth (intra-parenchymal) electrode recordings. RESULTS: (1) Depolarization events can be reliably detected from intra-cortically placed...

  2. Postoperative control in deep brain stimulation of the subthalamic region: the contact membership concept

    Energy Technology Data Exchange (ETDEWEB)

    Hemm, Simone; Lemaire, Jean-Jacques [Inserm, ERI 14, Equipe de Recherche en Imagerie Medicale, Clermont-Ferrand (France); CHU Clermont-Ferrand, Service de Neurochirurgie A, Hopital Gabriel Montpied, BP 69, Clermont-Ferrand Cedex 1 (France); Caire, Francois [Hopital Dupuytren, Service de Neurochirurgie, CHU Limoges, Limoges (France); Coste, Jerome [CHU Clermont-Ferrand, Service de Neurochirurgie A, Hopital Gabriel Montpied, BP 69, Clermont-Ferrand Cedex 1 (France); Vassal, Francois; Nuti, Christophe [Hopital Bellevue, Service de Neurochirurgie, CHU Saint-Etienne, Saint-Etienne (France); Derost, Philippe; Durif, Franck [Hopital Gabriel Montpied, Service de Neurologie, CHU Clermont-Ferrand, Clermont-Ferrand (France); Ouchchane, Lemlih [Universite Clermont-Ferrand 1, UFR Medecine, Unite de Bio Statistiques, Telematique et Traitementd' Image, Clermont-Ferrand (France); Sarry, Laurent [Inserm, ERI 14, Equipe de Recherche en Imagerie Medicale, Clermont-Ferrand (France)

    2008-06-15

    In deep brain stimulation, the anatomic positions of electrode contact centers are used as the basis for analysis. We propose a new semi-quantitative approach (contact membership concept) considering patient's individual anatomy, contact size, and extent of involvement of STN and neighboring structures. In ten bilaterally operated and improved Parkinsonian patients, effective contact positions (contacts used for monopolar stimulation) were analyzed. The position of the contact center (classical binary approach: each center assigned, 1, or not, 0, to a given structure) and of the contact in its dimension (contact membership concept: membership degree, ordinal values from 0 to 1, assigned to each anatomic structure according to extent of involvement) were compared for the whole patient group and, individually, for each patient. The membership concept revealed that for 13 out of 20 contacts, more than one structure was involved, where the classical binary approach assigned only one structure. For both approaches lateral STN, zona incerta and H1 (Forel's Field) were the main structures involved, but their frequencies of appearance differed. The membership concept allows detailed analysis of the anatomic contact position. In the future this approach could assist in correlating anatomy and clinical results for all electrode contacts (effective ones and clinically less efficient ones). (orig.)

  3. Effects of vestibular prosthesis electrode implantation and stimulation on hearing in rhesus monkeys.

    Science.gov (United States)

    Dai, Chenkai; Fridman, Gene Y; Della Santina, Charles C

    2011-07-01

    To investigate the effects of vestibular prosthesis electrode implantation and activation on hearing in rhesus monkeys, we measured auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE) in four rhesus monkeys before and after unilateral implantation of vestibular prosthesis electrodes in each of 3 left semicircular canals (SCC). Each of the 3 left SCCs were implanted with electrodes via a transmastoid approach. Right ears, which served as controls, were not surgically manipulated. Hearing tests were conducted before implantation (BI) and then 4 weeks post-implantation both without electrical stimulation (NS) and with electrical stimulation (S). During the latter condition, prosthetic electrical stimuli encoding 3 dimensions of head angular velocity were delivered to the 3 ampullary branches of the left vestibular nerve via each of 3 electrode pairs of a multichannel vestibular prosthesis. Electrical stimuli comprised charge-balanced biphasic pulses at a baseline rate of 94 pulses/s, with pulse frequency modulated from 48 to 222 pulses/s by head angular velocity. ABR hearing thresholds to clicks and tone pips at 1, 2, and 4 kHz increased by 5-10 dB from BI to NS and increased another ∼5 dB from NS to S in implanted ears. No significant change was seen in right ears. DPOAE amplitudes decreased by 2-14 dB from BI to NS in implanted ears. There was a slight but insignificant decrease of DPOAE amplitude and a corresponding increase of DPOAE/Noise floor ratio between NS and S in implanted ears. Vestibular prosthesis electrode implantation and activation have small but measurable effects on hearing in rhesus monkeys. Coupled with the clinical observation that patients with cochlear implants only rarely exhibit signs of vestibular injury or spurious vestibular nerve stimulation, these results suggest that although implantation and activation of multichannel vestibular prosthesis electrodes in human will carry a risk of hearing loss

  4. Modulation of untruthful responses with noninvasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Shirley eFecteau

    2013-02-01

    Full Text Available Deceptive abilities have long been studied in relation to personality traits. More recently, studies explored the neural substrates associated with deceptive skills suggesting a critical role of the prefrontal cortex. Here we investigated whether noninvasive brain stimulation over the dorsolateral prefrontal cortex (DLPFC could modulate generation of untruthful responses about subject’s personal life across contexts (i.e., deceiving on guilt-free questions on daily activities; generating previously memorized lies about past experience; and producing spontaneous lies about past experience, as well as across modality responses (verbal and motor responses. Results reveal that real, but not sham, transcranial direct current stimulation (tDCS over the DLPFC can reduce response latency for untruthful over truthful answers across contexts and modality responses. Also, contexts of lies seem to incur a different hemispheric laterality. These findings add up to previous studies demonstrating that it is possible to modulate some processes involved in generation of untruthful answers by applying noninvasive brain stimulation over the DLPFC and extend these findings by showing a differential hemispheric contribution of DLPFCs according to contexts.

  5. MRI magnetic field stimulates rotational sensors of the brain.

    Science.gov (United States)

    Roberts, Dale C; Marcelli, Vincenzo; Gillen, Joseph S; Carey, John P; Della Santina, Charles C; Zee, David S

    2011-10-11

    Vertigo in and around magnetic resonance imaging (MRI) machines has been noted for years [1, 2]. Several mechanisms have been suggested to explain these sensations [3, 4], yet without direct, objective measures, the cause is unknown. We found that all of our healthy human subjects developed a robust nystagmus while simply lying in the static magnetic field of an MRI machine. Patients lacking labyrinthine function did not. We use the pattern of eye movements as a measure of vestibular stimulation to show that the stimulation is static (continuous, proportional to static magnetic field strength, requiring neither head movement nor dynamic change in magnetic field strength) and directional (sensitive to magnetic field polarity and head orientation). Our calculations and geometric model suggest that magnetic vestibular stimulation (MVS) derives from a Lorentz force resulting from interaction between the magnetic field and naturally occurring ionic currents in the labyrinthine endolymph fluid. This force pushes on the semicircular canal cupula, leading to nystagmus. We emphasize that the unique, dual role of endolymph in the delivery of both ionic current and fluid pressure, coupled with the cupula's function as a pressure sensor, makes magnetic-field-induced nystagmus and vertigo possible. Such effects could confound functional MRI studies of brain behavior, including resting-state brain activity.

  6. Analgesia in conjunction with normalisation of thermal sensation following deep brain stimulation for central post-stroke pain.

    Science.gov (United States)

    Pickering, Anthony E; Thornton, Simon R; Love-Jones, Sarah J; Steeds, Charlotte; Patel, Nikunj K

    2009-12-15

    The aetiology of central post-stroke pain (CPSP) is poorly understood and such pains are often refractory to treatment. We report the case of a 56-year-old man, who, following a temporo-parietal infarct, suffered from debilitating and refractory hemi-body cold dysaesthesia and severe tactile allodynia. This was associated with thermal and tactile hypoaesthesia and hypoalgesia on his affected side. Implantation of a deep brain stimulating electrode in his periventricular gray (PVG) region produced an improvement in his pain that was associated with a striking normalisation of his deficits in somatosensory perception. This improvement in pain and thermal sensibility was reversed as stimulation became less effective, because of increased electrode impedance. Therefore, we postulate that the analgesic benefit may have occurred as a consequence of the normalisation of somatosensory function and we discuss these findings in relation to the theories of central pain generation and the potential to engage useful plasticity in central circuits.

  7. Anesthesia for deep brain stimulation in traumatic brain injury-induced hemidystonia

    OpenAIRE

    Jani, Jill M; Oluigbo, Chima O; Reddy, Srijaya K

    2015-01-01

    Key Clinical Message Deep brain stimulation in an awake patient presents several unique challenges to the anesthesiologist. It is important to understand the various stages of the procedure and the complexities of anesthetic management in order to have a successful surgical outcome and provide a safe environment for the patient.

  8. Anesthesia for deep brain stimulation in traumatic brain injury-induced hemidystonia.

    Science.gov (United States)

    Jani, Jill M; Oluigbo, Chima O; Reddy, Srijaya K

    2015-06-01

    Deep brain stimulation in an awake patient presents several unique challenges to the anesthesiologist. It is important to understand the various stages of the procedure and the complexities of anesthetic management in order to have a successful surgical outcome and provide a safe environment for the patient.

  9. How electrode montage affects transcranial direct current stimulation of the human motor cortex.

    Science.gov (United States)

    Salvador, Ricardo; Wenger, Cornelia; Nitsche, Michael A; Miranda, Pedro C

    2015-01-01

    Several different electrode configurations were originally proposed to induce excitability changes in the hand area of the motor cortex in transcranial direct current stimulation (tDCS). However only one was found to efficiently affect cortical excitability: anode/cathode over the primary motor cortex and return electrode placed over the contralateral orbit (M-CF configuration). In this work we used the finite element method to calculate the electric field (E-field) induced in a realistic human head model in all the proposed electrode configurations. In order to analyze the results, average values of the E-field's magnitude and polar/azimuthal angles were calculated in several cortical motor and premotor areas which may have an effect on the output of the primary motor cortex. The average E-field's magnitude at the hand-knob (HK) was similar between the M-CF configuration (0.16 V/m) and a few other tested configurations, the same happening for the average polar angle (129°). However this configuration achieved the highest mean E-field values over premotor (PM) areas (0.21 V/m). These results show that the polar angle and the average magnitude of the E-field evaluated at the HK and at the PM cortex might be important parameters in predicting the success of a specific electrode montage in tDCS.

  10. Enhanced tissue integration of implantable electrodes for sensing, and stimulation, via radio frequency glow discharge

    Science.gov (United States)

    O'Connor, Laurie M.

    Biopotential electrodes are conductive materials that convert electronic currents to or from ionic currents for sensing, and stimulating specific tissue sites for medical applications. Implanted electrodes become "walled off" by the foreign body tissue reactions producing poorly attached scar capsules dominated by surrounding dense collagenous lamellae and source fibroblasts which are electrically resistive. The conductive interstitial fluid that is typical between an electrode and the resistive capsule allows spurious current paths. The insulating layer increases the distance between the electrode and the target sites and poor attachment often results in electrode migration within the host tissue. This investigation tested the hypothesis that surface-energy modulation of electrodes, via Radio Frequency Glow Discharge Treatment (RFGDT), can improve the performance of tissue-implantable electrodes by reducing the foreign body tissue reaction and enhancing interfacial bonding between the tissue and electrode material. Previously published findings were reproduced in a pilot study of explanted reference grade medical-grade methyl silicone (PDMS) and commercially pure titanium (cpTi) materials and their tissue capsules from 30-day subcutaneous exposures in Balb/C mice. The low-critical surface tension PDMS produced thick, dense, poorly attached scar capsules while the higher-surface-energy commercially pure titanium (cpTi) produced more cellular and strongly attached tissue layers difficult to delaminate from the biomaterial. For the main body of work, cpTi, capacitor-grade Tantalum (Ta), and synthetic heart valve-quality Pyrolytic Carbon (PyC) were evaluated, representative of potential high-surface-energy implant electrode materials. Their surface characteristics were determined as-manufactured and after Radio Frequency Glow Discharge Treatment (RFGDT) by Critical Surface Tension (CST) measurement, Scanning Electron Microscopy (SEM), Energy Dispersive X

  11. [Deep brain stimulation: a review on current research].

    Science.gov (United States)

    Conca, Andreas; Di Pauli, Jan; Hinterhuber, Hartmann; Kapfhammer, Hans-Peter

    2011-01-01

    Recently Deep brain stimulation (DBS) has found continuous use in treatment of neurological movement disorders. However DBS in psychiatric illnesses is less investigated. Its application in depression, obsessive-compulsive disorder, and therapy-resistant Tourette- Syndrome shows positive effects and offers an advanced alternative to neurosurgical therapies of the past. There are also case reports suggesting therapeutic benefits in schizophrenia and addiction. To a large extent, the mechanisms of action appear to be still unknown; the side effects seem partially modulated through the stimulation parameters. Furthermore, some ethics committees argue that DBS exhibits a relevant impact on the personality. The novel approach as well as the unknown long term effects of DBS implicate that the technique can be performed only under strict individual diagnosis and rigorous consideration of all ethical concerns.

  12. Vocal Tremor: Novel Therapeutic Target for Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Vinod K. Ravikumar

    2016-10-01

    Full Text Available Tremulous voice is characteristically associated with essential tremor, and is referred to as essential vocal tremor (EVT. Current estimates suggest that up to 40% of individuals diagnosed with essential tremor also present with EVT, which is associated with an impaired quality of life. Traditional EVT treatments have demonstrated limited success in long-term management of symptoms. However, voice tremor has been noted to decrease in patients receiving deep brain stimulation (DBS with the targeting of thalamic nuclei. In this study, we describe our multidisciplinary procedure for awake, frameless DBS with optimal stimulation targets as well as acoustic analysis and laryngoscopic assessment to quantify tremor reduction. Finally, we investigate the most recent clinical evidence regarding the procedure.

  13. Surgery insight: Deep brain stimulation for movement disorders.

    Science.gov (United States)

    Anderson, William S; Lenz, Frederick A

    2006-06-01

    Over the past two decades, deep brain stimulation (DBS) has supplanted lesioning techniques for the treatment of movement disorders, and has been shown to be safe and efficacious. The primary therapeutic indications for DBS are essential tremor, dystonia and Parkinson's disease. In the case of Parkinson's disease, DBS is effective for treating the primary symptoms--tremor, bradykinesia and rigidity--as well as the motor complications of drug treatment. Progress has been made in understanding the effects of stimulation at the neuronal level, and this knowledge should eventually improve the effectiveness of this therapy. Preliminary studies also indicate that DBS might be used to treat Tourette's syndrome, obsessive-compulsive disorder, depression and epilepsy. As we will discuss in this review, the success of DBS depends on an appropriate rationale for the procedure, and on collaborations between neurologists and neurosurgeons in defining outcomes.

  14. The modulatory effect of adaptive deep brain stimulation on beta bursts in Parkinson's disease.

    Science.gov (United States)

    Tinkhauser, Gerd; Pogosyan, Alek; Little, Simon; Beudel, Martijn; Herz, Damian M; Tan, Huiling; Brown, Peter

    2017-02-13

    Adaptive deep brain stimulation uses feedback about the state of neural circuits to control stimulation rather than delivering fixed stimulation all the time, as currently performed. In patients with Parkinson's disease, elevations in beta activity (13-35 Hz) in the subthalamic nucleus have been demonstrated to correlate with clinical impairment and have provided the basis for feedback control in trials of adaptive deep brain stimulation. These pilot studies have suggested that adaptive deep brain stimulation may potentially be more effective, efficient and selective than conventional deep brain stimulation, implying mechanistic differences between the two approaches. Here we test the hypothesis that such differences arise through differential effects on the temporal dynamics of beta activity. The latter is not constantly increased in Parkinson's disease, but comes in bursts of different durations and amplitudes. We demonstrate that the amplitude of beta activity in the subthalamic nucleus increases in proportion to burst duration, consistent with progressively increasing synchronization. Effective adaptive deep brain stimulation truncated long beta bursts shifting the distribution of burst duration away from long duration with large amplitude towards short duration, lower amplitude bursts. Critically, bursts with shorter duration are negatively and bursts with longer duration positively correlated with the motor impairment off stimulation. Conventional deep brain stimulation did not change the distribution of burst durations. Although both adaptive and conventional deep brain stimulation suppressed mean beta activity amplitude compared to the unstimulated state, this was achieved by a selective effect on burst duration during adaptive deep brain stimulation, whereas conventional deep brain stimulation globally suppressed beta activity. We posit that the relatively selective effect of adaptive deep brain stimulation provides a rationale for why this approach could

  15. Weight change following deep brain stimulation for movement disorders.

    Science.gov (United States)

    Strowd, Roy E; Cartwright, Michael S; Passmore, Leah V; Ellis, Thomas L; Tatter, Stephen B; Siddiqui, Mustafa S

    2010-08-01

    Patients with Parkinson's disease (PD) and essential tremor (ET) tend to lose weight progressively over years. Weight gain following deep brain stimulation (DBS) of the subthalamic nucleus (STN) for treatment of PD has been documented in several studies that were limited by small sample size and exclusive focus on PD patients with STN stimulation. The current study was undertaken to examine weight change in a large sample of movement disorder patients following DBS. A retrospective review was undertaken of 182 patient charts following DBS of the STN, ventralis intermedius nucleus of the thalamus (VIM), and globus pallidus internus (GPi). Weight was collected preoperatively and postoperatively up to 24 months following surgery. Data were adjusted for baseline weight and multivariate linear regression was performed with repeated measures to assess weight change. Statistically significant mean weight gain of 1.8 kg (2.8% increase from baseline, p = 0.0113) was observed at a rate of approximately 1 kg per year up to 24 months following surgery. This gain was not predicted by age, gender, diagnosis, or stimulation target in a multivariate model. Significant mean weight gain of 2.3 kg (p = 0.0124) or 4.2% was observed in our PD patients. Most patients with PD and ET gain weight following DBS, and this gain is not predicted by age, gender, diagnosis, or stimulation target.

  16. Magnetic resonance imaging safety of deep brain stimulator devices.

    Science.gov (United States)

    Oluigbo, Chima O; Rezai, Ali R

    2013-01-01

    Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices.

  17. Current Topics in Deep Brain Stimulation for Parkinson Disease

    Science.gov (United States)

    UMEMURA, Atsushi; OYAMA, Genko; SHIMO, Yasushi; NAKAJIMA, Madoka; NAKAJIMA, Asuka; JO, Takayuki; SEKIMOTO, Satoko; ITO, Masanobu; MITSUHASHI, Takumi; HATTORI, Nobutaka; ARAI, Hajime

    2016-01-01

    There is a long history of surgical treatment for Parkinson disease (PD). After pioneering trials and errors, the current primary surgical treatment for PD is deep brain stimulation (DBS). DBS is a promising treatment option for patients with medically refractory PD. However, there are still many problems and controversies associated with DBS. In this review, we discuss current issues in DBS for PD, including patient selection, clinical outcomes, complications, target selection, long-term outcomes, management of axial symptoms, timing of surgery, surgical procedures, cost-effectiveness, and new technology. PMID:27349658

  18. Authenticity or autonomy? When deep brain stimulation causes a dilemma.

    Science.gov (United States)

    Kraemer, Felicitas

    2013-12-01

    While deep brain stimulation (DBS) for patients with Parkinson's disease has typically raised ethical questions about autonomy, accountability and personal identity, recent research indicates that we need to begin taking into account issues surrounding the patients' feelings of authenticity and alienation as well. In order to bring out the relevance of this dimension to ethical considerations of DBS, I analyse a recent case study of a Dutch patient who, as a result of DBS, faced a dilemma between autonomy and authenticity. This case study is meant to point out the normatively meaningful tension patients under DBS experience between authenticity and autonomy.

  19. Deep brain stimulation for the treatment of vegetative state.

    Science.gov (United States)

    Yamamoto, Takamitsu; Katayama, Yoichi; Kobayashi, Kazutaka; Oshima, Hideki; Fukaya, Chikashi; Tsubokawa, Takashi

    2010-10-01

    One hundred and seven patients in vegetative state (VS) were evaluated neurologically and electrophysiologically over 3 months (90 days) after the onset of brain injury. Among these patients, 21 were treated with deep brain stimulation (DBS). The stimulation sites were the mesencephalic reticular formation (two patients) and centromedian-parafascicularis nucleus complex (19 cases). Eight of the patients recovered from VS and were able to obey verbal commands at 13 and 10 months in the case of head trauma and at 19, 14, 13, 12, 12 and 8 months in the case of vascular disease after comatose brain injury, and no patients without DBS recovered from VS spontaneously within 24 months after brain injury. The eight patients who recovered from VS showed desynchronization on continuous EEG frequency analysis. The Vth wave of the auditory brainstem response and N20 of the somatosensory evoked potential could be recorded, although with a prolonged latency, and the pain-related P250 was recorded with an amplitude of > 7 μV. Sixteen (14.9%) of the 107 VS patients satisfied these criteria in our electrophysiological evaluation, 10 of whom were treated with DBS and six of whom were not treated with DBS. In these 16 patients, the recovery rate from VS was different between the DBS therapy group and the no DBS therapy group (P < 0.01, Fisher's exact probability test) These findings indicate that DBS may be useful for the recovery of patients from VS if the candidates are selected on the basis of electrophysiological criteria.

  20. Functional asymmetry between the left and right human fusiform gyrus explored through electrical brain stimulation.

    Science.gov (United States)

    Rangarajan, Vinitha; Parvizi, Josef

    2016-03-01

    The ventral temporal cortex (VTC) contains several areas with selective responses to words, numbers, faces, and objects as demonstrated by numerous human and primate imaging and electrophysiological studies. Our recent work using electrocorticography (ECoG) confirmed the presence of face-selective neuronal populations in the human fusiform gyrus (FG) in patients implanted with intracranial electrodes in either the left or right hemisphere. Electrical brain stimulation (EBS) disrupted the conscious perception of faces only when it was delivered in the right, but not left, FG. In contrast to our previous findings, here we report both negative and positive EBS effects in right and left FG, respectively. The presence of right hemisphere language dominance in the first, and strong left-handedness and poor language processing performance in the second case, provide indirect clues about the functional architecture of the human VTC in relation to hemispheric asymmetries in language processing and handedness.

  1. Effects of Intramuscular Electrical Stimulation Using Inversely Placed Electrodes on Myofascial Pain Syndrome in the Shoulder: A Case Series

    Science.gov (United States)

    Mathias, Lawrence; Thakur, Ajay; Kumar, Dhanesh

    2016-01-01

    Myofascial pain syndrome (MPS) is one of the common musculoskeletal conditions of the shoulder which may develop sensory-motor and autonomic dysfunctions at the various level of the neuromuscular system. The pain and dysfunction caused by MPS were primarily treated with physical therapy and pharmacological agents in order to achieve painfree movements. However, in recent years intramuscular electrical stimulation (IMES) with conventional electrode placement was used by researchers to maximise therapeutic values. But, in this study an inverse electrode placement was used to deliver electrical impulses intramuscularly to achieve neuro-modulation at the various level of the nervous system. Nine patients with MPS were treated with intramuscular electrode stimulation using inversely placed electrodes for a period of three weeks. All nine subjects recovered from their shoulder pain and disability within the few weeks of intervention. So, this inverse electrode placement may be more appropriate for chronic pain management. PMID:27103970

  2. Effects of Intramuscular Electrical Stimulation Using Inversely Placed Electrodes on Myofascial Pain Syndrome in the Shoulder: A Case Series.

    Science.gov (United States)

    Shanmugam, Sukumar; Mathias, Lawrence; Thakur, Ajay; Kumar, Dhanesh

    2016-04-01

    Myofascial pain syndrome (MPS) is one of the common musculoskeletal conditions of the shoulder which may develop sensory-motor and autonomic dysfunctions at the various level of the neuromuscular system. The pain and dysfunction caused by MPS were primarily treated with physical therapy and pharmacological agents in order to achieve painfree movements. However, in recent years intramuscular electrical stimulation (IMES) with conventional electrode placement was used by researchers to maximise therapeutic values. But, in this study an inverse electrode placement was used to deliver electrical impulses intramuscularly to achieve neuro-modulation at the various level of the nervous system. Nine patients with MPS were treated with intramuscular electrode stimulation using inversely placed electrodes for a period of three weeks. All nine subjects recovered from their shoulder pain and disability within the few weeks of intervention. So, this inverse electrode placement may be more appropriate for chronic pain management.

  3. Deep brain stimulation: a paradigm shifting approach to treat Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Patrick eHickey

    2016-04-01

    Full Text Available Parkinson disease (PD is a chronic and progressive movement disorder classically characterized by slowed voluntary movements, resting tremor, muscle rigidity, and impaired gait and balance. Medical treatment is highly successful early on, though the majority of people experience significant complications in later stages. In advanced PD, when medications no longer adequately control motor symptoms, deep brain stimulation (DBS offers a powerful therapeutic alternative. DBS involves the surgical implantation of one or more electrodes into specific areas of the brain, which modulate or disrupt abnormal patterns of neural signaling within the targeted region. Outcomes are often dramatic following DBS, with improvements in motor function and reductions motor complications having been repeatedly demonstrated. Given such robust responses, emerging indications for DBS are being investigated. In parallel with expansions of therapeutic scope, advancements within the areas of neurosurgical technique and the precision of stimulation delivery have recently broadened as well. This review focuses on the revolutionary addition of DBS to the therapeutic armamentarium for PD, and summarizes the technological advancements in the areas of neuroimaging and biomedical engineering intended to improve targeting, programming and overall management.

  4. Coupling BCI and cortical stimulation for brain-state-dependent stimulation: Methods for spectral estimation in the presence of stimulation after-effects

    Directory of Open Access Journals (Sweden)

    Armin eWalter

    2012-11-01

    Full Text Available Brain-state-dependent stimulation combines brain-computer interfaces (BCI and cortical stimulation into one paradigm that allows the online decoding for example of movement intention from brain signals while simultaneously applying stimulation. If the BCI decoding is performed by spectral features, stimulation after-effects such as artefacts and evoked activity present a challenge for a successful implementation of brain-state-dependent stimulation because they can impair the detection of targeted brain states. Therefore, efficient and robust methods are needed to minimize the influence of the stimulation-induced effects on spectral estimation without violating the real-time constraints of the BCI.In this work, we compared 4 methods for spectral estimation with autoregressive (AR models in the presence of pulsed cortical stimulation. Using combined EEG-TMS as well as combined ECoG and epidural electrical stimulation, 3 patients performed a motor task using a sensorimotor-rhythm BCI. Three stimulation paradigms were varied between sessions: (1 no stimulation, (2 single stimulation pulses applied independently (open-loop or (3 coupled to the BCI output (closed-loop such that stimulation was given only while an intention to move was detected using neural data.We found that removing the stimulation after-effects by linear interpolation can introduce a bias in the estimation of the spectral power of the sensorimotor rhythm, leading to an overestimation of decoding performance in the closed-loop setting. We propose the use of the Burg algorithm for segmented data to deal with stimulation after-effects. This work shows that the combination of BCIs controlled with spectral features and cortical stimulation in a closed-loop fashion is possible when the influence of stimulation after-effects on spectral estimation is minimized.

  5. Biofouling resistance of boron-doped diamond neural stimulation electrodes is superior to titanium nitride electrodes in vivo

    DEFF Research Database (Denmark)

    Meijs, Suzan; Alcaide, Maria; Sørensen, Charlotte;

    2016-01-01

    OBJECTIVE: The goal of this study was to assess the electrochemical properties of boron-doped diamond (BDD) electrodes in relation to conventional titanium nitride (TiN) electrodes through in vitro and in vivo measurements. APPROACH: Electrochemical impedance spectroscopy, cyclic voltammetry and ...... electrodes possess a superior biofouling resistance, which provides significantly stable electrochemical properties both in protein solution as well as in vivo compared to TiN electrodes....

  6. Continuous theta burst transcranial magnetic stimulation affects brain functional connectivity.

    Science.gov (United States)

    Dan Cao; Yingjie Li; Ling Wei; Yingying Tang

    2016-08-01

    Prefrontal cortex (PFC) plays an important role in the emotional processing as well as in the functional brain network. Hyperactivity in the right dorsolateral prefrontal cortex (DLPFC) would be found in anxious participants. However, it is still unclear what the role of PFC played in a resting functional network. Continuous theta burst transcranial magnetic stimulation (cTBS) is an effective tool to create virtual lesions on brain regions. In this paper, we applied cTBS over right prefrontal area, and investigated the effects of cTBS on the brain activity for functional connectivity by the method of graph theory. We recorded 64-channels EEG on thirteen healthy participants in the resting condition and emotional tasks before and after 40 s of cTBS. This work focused on the effect of cTBS on cortical activities in the resting condition by calculating the coherence between EEG channels and building functional networks before and after cTBS in the delta, theta, alpha and beta bands. Results revealed that 1) The functional connectivity after cTBS was significantly increased compared with that before cTBS in delta, theta, alpha and beta bands in the resting condition; 2) The efficiency-cost reached the maximum before and after cTBS both with the cost about 0.3 in the bands above, which meant that the information transmission of functional brain network with this cost was highly efficient; 3) the clustering coefficient and path length after cTBS was significantly increased in delta, theta and beta bands. In conclusion, cTBS over PFC indeed enhanced the functional connectivity in the resting condition. In addition, the information transmission in the resting brain network was highly efficient with the cost about 0.3.

  7. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study.

    Science.gov (United States)

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson's disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target.

  8. Nerve cuff electrode using embedded magnets and its application to hypoglossal nerve stimulation

    Science.gov (United States)

    Seo, Jungmin; Hye Wee, Jee; Hoan Park, Jeong; Park, Pona; Kim, Jeong-Whun; Kim, Sung June

    2016-12-01

    Objective. A novel nerve cuff electrode with embedded magnets was fabricated and developed. In this study, a pair of magnets was fully embedded and encapsulated in a liquid crystal polymer (LCP) substrate to utilize magnetic force in order to replace the conventional installing techniques of cuff electrodes. In vitro and in vivo experiments were conducted to evaluate the feasibility of the magnet-embedded nerve cuff electrode (MENCE). Lastly, several issues pertaining to the MENCE such as the cuff-to-nerve diameter ratio, the force of the magnets, and possible concerns were discussed in the discussion section. Approach. Electrochemical impedance spectrum and cyclic voltammetry assessments were conducted to measure the impedance and charge storage capacity of the cathodal phase (CSCc). The MENCE was installed onto the hypoglossal nerve (HN) of a rabbit and the movement of the genioglossus was recorded through C-arm fluoroscopy while the HN was stimulated by a pulsed current. Main results. The measured impedance was 0.638 ∠ -67.8° kΩ at 1 kHz and 5.27 ∠ -82.1° kΩ at 100 Hz. The average values of access resistance and cut-off frequency were 0.145 kΩ and 3.98 kHz, respectively. The CSCc of the electrode was measured as 1.69 mC cm-2 at the scan rate of 1 mV s-1. The movement of the genioglossus contraction was observed under a pulsed current with an amplitude level of 0.106 mA, a rate of 0.635 kHz, and a duration of 0.375 ms applied through the MENCE. Significance. A few methods to close and secure cuff electrodes have been researched, but they are associated with several drawbacks. To overcome these, we used magnetic force as a closing method of the cuff electrode. The MENCE can be precisely installed on a target nerve without any surgical techniques such as suturing or molding. Furthermore, it is convenient to remove the installed MENCE because it requires little force to detach one magnet from the other, enabling repeatable installation and removal. We

  9. Coupling of organotypic brain slice cultures to silicon-based arrays of electrodes

    DEFF Research Database (Denmark)

    Jahnsen, Henrik; Kristensen, Bjarne Winther; Thiébaud, P

    1999-01-01

    such hippocampal rat brain slice cultures on biocompatible silicon-based chips with arrays of electrodes with a histological organization comparable to that of conventional brain slice cultures grown by the roller drum technique and on semiporous membranes. Intracellular and extracellular recordings from neurons......Fetal or early postnatal brain tissue can be cultured in viable and healthy condition for several weeks with development and preservation of the basic cellular and connective organization as so-called organotypic brain slice cultures. Here we demonstrate and describe how it is possible to establish...

  10. Optogenetically inspired deep brain stimulation: linking basic with clinical research.

    Science.gov (United States)

    Lüscher, Christian; Pollak, Pierre

    2016-01-01

    In the last decade, optogenetics has revolutionised the neurosciences. The technique, which allows for cell-type specific excitation and inhibition of neurons in the brain of freely moving rodents, has been used to tighten the links of causality between neural activity and behaviour. Optogenetics is also enabling an unprecedented characterisation of circuits and their dysfunction in a number of brain diseases, above all those conditions that are not caused by neurodegeneration. Notable progress has been made in addiction, depression and obsessive-compulsive disorders, as well as other anxiety disorders. By extension, the technique has also been used to propose blueprints for innovative rational treatment of these diseases. The goal is to design manipulations that disrupt pathological circuit function or restore normal activity. This can be achieved by targeting specific projections in order to apply specific stimulation protocols validated by ex-vivo analysis of the mechanisms underlying the dysfunction. In a number of cases, specific forms of pathological synaptic plasticity have been implicated. For example, addictive drugs via strong increase of dopamine trigger a myriad of alterations of glutamate and γ-aminobutyric acid transmission, also called drug-evoked synaptic plasticity. This opens the way to the design of optogenetic reversal protocols, which might restore normal transmission with the hope to abolish the pathological behaviour. Several proof of principle studies for this approach have recently been published. However, for many reasons, optogenetics will not be translatable to human applications in the near future. Here, we argue that an intermediate step is novel deep brain stimulation (DBS) protocols that emulate successful optogenetic approaches in animal models. We provide a roadmap for a translational path to rational, optogenetically inspired DBS protocols to refine existing approaches and expand to novel indications.

  11. Deep brain stimulation for enhancement of learning and memory.

    Science.gov (United States)

    Suthana, Nanthia; Fried, Itzhak

    2014-01-15

    Deep brain stimulation (DBS) has emerged as a powerful technique to treat a host of neurological and neuropsychiatric disorders from Parkinson's disease and dystonia, to depression, and obsessive compulsive disorder (Benabid et al., 1987; Lang and Lozano, 1998; Davis et al., 1997; Vidailhet et al., 2005; Mayberg et al., 2005; Nuttin et al., 1999). More recently, results suggest that DBS can enhance memory for facts and events that are dependent on the medial temporal lobe (MTL), thus raising the possibility for DBS to be used as a treatment for MTL- related neurological disorders (e.g. Alzheimer's disease, temporal lobe epilepsy, and MTL injuries). In the following review, we summarize key results that show the ability of DBS or cortical surface stimulation to enhance memory. We also discuss current knowledge regarding the temporal specificity, underlying neurophysiological mechanisms of action, and generalization of stimulation's effects on memory. Throughout our discussion, we also propose several future directions that will provide the necessary insight into if and how DBS could be used as a therapeutic treatment for memory disorders.

  12. Waking up the brain: a case study of stimulation-induced wakeful unawareness during anaesthesia.

    Science.gov (United States)

    Moll, Christian K E; Sharott, Andrew; Hamel, Wolfgang; Münchau, Alexander; Buhmann, Carsten; Hidding, Ute; Zittel, Simone; Westphal, Manfred; Müller, Dieter; Engel, Andreas K

    2009-01-01

    Hitherto, little is known about the specific functional contributions of extrathalamic arousal systems to the regulation of wakefulness in humans. Here, we describe a 42-year-old woman with treatment resistant tremulous cervical dystonia who underwent microelectrode-guided stereotactic implantation of deep brain stimulation (DBS) electrodes in the internal segment of the globus pallidus internus (GPi) under general anaesthesia. Acute unilateral DBS of circumscribed sites within the subpallidal fibre-field with 130 Hz caused a transient state of wakefulness with an increased responsiveness to external stimuli but without detectable signs of conscious awareness. The extent of behavioural arousal could be titrated as a function of stimulus intensity. At lower stimulation intensities, bilateral eye opening occurred in response to verbal commands or tactile stimulation. At suprathreshold intensities, the patient's eyes remained open and conjugated throughout the stimulation period. The arousal effect ceased abruptly when DBS was discontinued. Behavioural arousal was accompanied by global cortical EEG activation in the gamma-frequency range (40-120 Hz) and by autonomic activation as evidenced by increased heart rate. The observed effect was reproducible in both hemispheres and topographically restricted to 6 out of 15 tested sites in the fibre-field between the GPi and the posterior aspect of the basal nucleus of Meynert. We conclude that the stimulated neural substrate in the subpallidal basal forebrain is involved in the premotor control of lid and eye position and the control of the activation state of the human neocortex. It may thus be important for the induction and maintenance of anaesthesia-induced unconsciousness in humans. It is suggested that subpallidal DBS released a downstream arousal circuit from anaesthesia-related inhibitory modulation either by direct excitation of an arousal nucleus or by inhibition of a sleep-promoting centre in the basal forebrain.

  13. Theoretical study of rectangular pulse electrical stimulation (RPES) onskin cells (in vivo) under conforming electrodes.

    Science.gov (United States)

    Cheng, K; Tarjan, P P; Mertz, P M

    1993-01-01

    Our previous in vivo experimental results have shown RPES can enhance skin wound healing by using conforming electrodes. Based on an equation of polarization transmembrane voltage [Cole, K. S. 1972], two equations were derived to describe the peak RPES intensity on skin cells in vivo: (1) U = 1.5 a J/sigma, (2) Jm = 1.5 a (J/sigma) (Cm/tau). Where U: polarization transmembrane voltage. a: radius (R) for spherical cells or semi-length (L) for long fibers parallel to the electrical field. J: external imposed pulse current density under the electrode. sigma: average conductivity of skin tissue. Jm: transmembrane displacement current density. Cm: membrane capacitance per unit area and tau: time constant. Calculations indicated that the sensory fibers (SF) would receive the strongest stimulation compared to other cells in skin since generally LSF > or = 100 R. The sensitivity of SF to the stimulation could enhance skin wound healing as well as protect normal skin cells from harmful electroporation. From these theoretical calculations. We proposed a theoretical range of the pulse current density as: U1 sigma/(1.5 L) < or = J < or = U2 sigma/(1.5 L), where U1 and U2 are the excitation threshold voltage (about 0.01 V) and polarization electroporation voltage (about 0.1 V) for a SF respectively, for RPES to enhance skin wound healing.

  14. Evaluation of Platinum-Black Stimulus Electrode Array for Electrical Stimulation of Retinal Cells in Retinal Prosthesis System

    Science.gov (United States)

    Watanabe, Taiichiro; Kobayashi, Risato; Komiya, Ken; Fukushima, Takafumi; Tomita, Hiroshi; Sugano, Eriko; Kurino, Hiroyuki; Tanaka, Tetsu; Tamai, Makoto; Koyanagi, Mitsumasa

    2007-04-01

    A retinal prosthesis system with a three-dimensionally (3D) stacked LSI chip has been proposed. We fabricated a new implantable stimulus electrode array deposited with Platinum-black (Pt-b) on a polyimide-based flexible printed circuit (FPC) for the electrical stimulation of the retinal cells. Impedance measurement of the Pt-b electrode-electrolyte interface in a saline solution was performed and the Pt-b electrode realized a very low impedance. The power consumption at the electrode array when retinal cells were stimulated by a stimulus current was evaluated. The power consumption of the Pt-b stimulus electrode array was 91% lower than that of a previously fabricated Al stimulus electrode array due to a convexo-concave surface. In the cytotoxicity test (CT), we confirmed that Pt implantation induced no cellular degeneration of the rat retina. In the animal experiments, electrically evoked potential (EEP) was successfully recorded using Japanese white rabbits. These results indicate that electrical stimulation using the Pt-b stimulus electrode array can restore visual sensation.

  15. Influence of implantation on the electrochemical properties of smooth and porous TiN coatings for stimulation electrodes

    Science.gov (United States)

    Meijs, S.; Sørensen, C.; Sørensen, S.; Rechendorff, K.; Fjorback, M.; Rijkhoff, N. J. M.

    2016-04-01

    Objective. To determine whether changes in electrochemical properties of porous titanium nitride (TiN) electrodes as a function of time after implantation are different from those of smooth TiN electrodes. Approach. Eight smooth and 8 porous TiN coated electrodes were implanted in 8 rats. Before implantation, voltage transients, cyclic voltammograms and impedance spectra were recorded in phosphate buffered saline (PBS). After implantation, these measurements were done weekly to investigate how smooth and porous electrodes were affected by implantation. Main results. The electrode capacitance of the porous TiN electrodes decreased more than the capacitance of the smooth electrodes due to acute implantation under fast measurement conditions (such as stimulation pulses). This indicates that protein adhesion presents a greater diffusion limitation for counter-ions for the porous than for the smooth electrodes. The changes in electrochemical properties during the implanted period were similar for smooth and porous TiN electrodes, indicating that cell adhesion poses a similar diffusion limitation for smooth and porous electrodes. Significance. This knowledge can be used to optimize the porous structure of the TiN film, so that the effect of protein adhesion on the electrochemical properties is diminished. Alternatively, an additional coating could be applied on the porous TiN that would prevent or minimize protein adhesion.

  16. Clinical outcome of deep brain stimulation for Parkinson's disease.

    Science.gov (United States)

    Deuschl, Günther; Paschen, Steffen; Witt, Karsten

    2013-01-01

    Deep brain stimulation is one of the most effective treatments of Parkinson's disease (PD). This report summarizes the state of the art as at January 2013. Stimulation of the subthalamic nucleus is the most commonly used approach. It improves the core motor symptoms better than medication in patients with advanced disease. It also improves the majority of nonmotor symptoms, such as mood, impulse control disorders, sleep, and some autonomic dysfunctions. Quality of life (QoL) is improved significantly more than with medication. Long-term data show that the treatment is effective for up to 10 years, but the late appearance of l-dopa-resistant symptoms is seemingly not influenced. Internal globus pallidus (GPi) stimulation is less well studied but seems to have similar short-term efficacy. Importantly l-dopa use cannot be reduced with GPi DBS, which is a major disadvantage for patients suffering from medication side-effects, although gait may be influenced more positively. Although short-term QoL improvement seems to be similar to that for subthalamic nucleus (STN) DBS - gait and speech may be better improved - long-term data are rare for GPi DBS. Thalamic stimulation in the ventral intermediate nucleus (VIM) is applied only in tremor-dominant elderly patients. The treatment improves the dopa-sensitive symptoms and effectively reduces fluctuations leading to an overall QoL improvement. Although most of the controlled studies have been on advanced PD, the recently published EARLYSTIM study suggests that even patients with a very short duration of their fluctuations and dyskinesia are doing significantly better with neurostimulation in terms of QoL and all major motor outcome parameters.

  17. Novel semi-dry electrodes for brain-computer interface applications

    Science.gov (United States)

    Wang, Fei; Li, Guangli; Chen, Jingjing; Duan, Yanwen; Zhang, Dan

    2016-08-01

    Objectives. Modern applications of brain-computer interfaces (BCIs) based on electroencephalography rely heavily on the so-called wet electrodes (e.g. Ag/AgCl electrodes) which require gel application and skin preparation to operate properly. Recently, alternative ‘dry’ electrodes have been developed to increase ease of use, but they often suffer from higher electrode-skin impedance and signal instability. In the current paper, we have proposed a novel porous ceramic-based ‘semi-dry’ electrode. The key feature of the semi-dry electrodes is that their tips can slowly and continuously release a tiny amount of electrolyte liquid to the scalp, which provides an ionic conducting path for detecting neural signals. Approach. The performance of the proposed electrode was evaluated by simultaneous recording of the wet and semi-dry electrodes pairs in five classical BCI paradigms: eyes open/closed, the motor imagery BCI, the P300 speller, the N200 speller and the steady-state visually evoked potential-based BCI. Main results. The grand-averaged temporal cross-correlation was 0.95 ± 0.07 across the subjects and the nine recording positions, and these cross-correlations were stable throughout the whole experimental protocol. In the spectral domain, the semi-dry/wet coherence was greater than 0.80 at all frequencies and greater than 0.90 at frequencies above 10 Hz, with the exception of a dip around 50 Hz (i.e. the powerline noise). More importantly, the BCI classification accuracies were also comparable between the two types of electrodes. Significance. Overall, these results indicate that the proposed semi-dry electrode can effectively capture the electrophysiological responses and is a feasible alternative to the conventional dry electrode in BCI applications.

  18. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  19. Cerebellar tDCS Effects on Conditioned Eyeblinks using Different Electrode Placements and Stimulation Protocols.

    Science.gov (United States)

    Beyer, Linda; Batsikadze, Giorgi; Timmann, Dagmar; Gerwig, Marcus

    2017-01-01

    There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US). An extracephalic reference electrode was used in Experiment 1 and a cephalic reference in Experiment 2. In both parts the influence on unconditioned eyeblink responses (UR) was investigated by starting stimulation in the second half of the pseudoconditioning phase lasting throughout the first half of paired trials. In a third experiment, effects of cerebellar tDCS during 40 extinction trials were assessed on extinction and reacquisition on the next day. In each experiment, 30 subjects received anodal, cathodal or sham stimulation in a double-blinded fashion. Using the extracephalic reference electrode, no significant effects on CR incidences comparing stimulation groups were observed. Using the cephalic reference anodal as well as cathodal cerebellar tDCS increased CR acquisition compared to sham only on a trend level. Analysis of timing parameters did not reveal significant effects on CR onset and peaktime latencies nor on UR timing. In the third experiment, cerebellar tDCS during extinction trials had no significant effect on extinction and savings on the next day. The present study did not reveal clear polarity dependent effects of cerebellar tDCS on CR acquisition and timing as previously described. Weaker effects may be explained by start of tDCS before the learning phase i.e., offline, individual thresholds and current flow based

  20. Using brain-computer interfaces and brain-state dependent stimulation as tools in cognitive neuroscience

    Directory of Open Access Journals (Sweden)

    Ole eJensen

    2011-05-01

    Full Text Available Large efforts are currently being made to develop and improve online analysis of brain activity which can be used e.g. for brain-computer interfacing (BCI. A BCI allows a subject to control a device by willfully changing his/her own brain activity. BCI therefore holds the promise as a tool for aiding the disabled and for augmenting human performance. While technical developments obviously are important, we will here argue that new insight gained from cognitive neuroscience can be used to identify signatures of neural activation which reliably can be modulated by the subject at will. This review will focus mainly on oscillatory activity in the alpha band which is strongly modulated by changes in covert attention. Besides developing BCIs for their traditional purpose, they might also be used as a research tool for cognitive neuroscience. There is currently a strong interest in how brain state fluctuations impact cognition. These state fluctuations are partly reflected by ongoing oscillatory activity. The functional role of the brain state can be investigated by introducing stimuli in real time to subjects depending on the actual state of the brain. This principle of brain-state dependent stimulation may also be used as a practical tool for augmenting human behavior. In conclusion, new approaches based on online analysis of ongoing brain activity are currently in rapid development. These approaches are amongst others informed by new insight gained from EEG/MEG studies in cognitive neuroscience and hold the promise of providing new ways for investigating the brain at work.

  1. Non-invasive brain stimulation for the treatment of symptoms following traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Simarjot K Dhaliwal

    2015-08-01

    Full Text Available Background: Traumatic brain injury (TBI is a common cause of physical, psychological, and cognitive impairment, but many current treatments for TBI are ineffective or produce adverse side effects. Non-invasive methods of brain stimulation could help ameliorate some common trauma-induced symptoms.Objective: This review summarizes instances in which repetitive Transcranial Magnetic Stimulation (rTMS and transcranial Direct Current Stimulation (tDCS have been used to treat symptoms following a traumatic brain injury. A subsequent discussion attempts to determine the value of these methods in light of their potential risks.Methods: The research databases of PubMed/MEDLINE and PsycINFO were electronically searched using terms relevant to the use of rTMS and tDCS as a tool to decrease symptoms in the context of rehabilitation post-TBI.Results: Eight case-studies and four multi-subject reports using rTMS and six multi-subject studies using tDCS were found. Two instances of seizure are discussed. Conclusions: There is evidence that rTMS can be an effective treatment option for some post-TBI symptoms such as depression, tinnitus, and neglect. Although the safety of this method remains uncertain, the use of rTMS in cases of mild-TBI without obvious structural damage may be justified. Evidence on the effectiveness of tDCS is mixed, highlighting the need for additional

  2. The practices of do-it-yourself brain stimulation: implications for ethical considerations and regulatory proposals.

    Science.gov (United States)

    Wexler, Anna

    2016-04-01

    Scientists and neuroethicists have recently drawn attention to the ethical and regulatory issues surrounding the do-it-yourself (DIY) brain stimulation community, which comprises individuals stimulating their own brains with transcranial direct current stimulation (tDCS) for self-improvement. However, to date, existing regulatory proposals and ethical discussions have been put forth without engaging those involved in the DIY tDCS community or attempting to understand the nature of their practices. I argue that to better contend with the growing ethical and safety concerns surrounding DIY tDCS, we need to understand the practices of the community. This study presents the results of a preliminary inquiry into the DIY tDCS community, with a focus on knowledge that is formed, shared and appropriated within it. I show that when making or acquiring a device, DIYers (as some members call themselves) produce a body of knowledge that is completely separate from that of the scientific community, and share it via online forums, blogs, videos and personal communications. However, when applying tDCS, DIYers draw heavily on existing scientific knowledge, posting links to academic journal articles and scientific resources and adopting the standardised electrode placement system used by scientists. Some DIYers co-opt scientific knowledge and modify it by creating their own manuals and guides based on published papers. Finally, I explore how DIYers cope with the methodological limitations inherent in self-experimentation. I conclude by discussing how a deeper understanding of the practices of DIY tDCS has important regulatory and ethical implications.

  3. Subthalamic nucleus deep brain stimulation in elderly patients – analysis of outcome and complications

    Directory of Open Access Journals (Sweden)

    Ostertag Christoph

    2007-03-01

    Full Text Available Abstract Background There is an ongoing discussion about age limits for deep brain stimulation (DBS. Current indications for DBS are tremor-dominant disorders, Parkinson's disease, and dystonia. Electrode implantation for DBS with analgesia and sedation makes surgery more comfortable, especially for elderly patients. However, the value of DBS in terms of benefit-risk ratio in this patient population is still uncertain. Methods Bilateral electrode implantation into the subthalamic nucleus (STN was performed in a total of 73 patients suffering from Parkinson's disease. Patients were analyzed retrospectively. For this study they were divided into two age groups: group I (age Results Significant differences were found in overall performance determined as ADL scores (group I: 48/71 points, group II: 41/62 points [preoperatively/6-month postoperatively] and in the rate of complications (group I: 4 transient psychosis, 4 infections in a total of 8 patients, group II: 2 deaths [unrelated to surgery], 1 intracerebral hemorrhage, 7 transient psychosis, 3 infections, 2 pneumonia in a total of 13 patients, (p Conclusion DBS of the STN is clinically as effective in elderly patients as it is in younger ones. However, a more careful selection and follow-up of the elderly patients are required because elderly patients have a higher risk of surgery-related complications and a higher morbidity rate.

  4. Early application of deep brain stimulation: clinical and ethical aspects.

    Science.gov (United States)

    Woopen, Christiane; Pauls, K Amande M; Koy, Anne; Moro, Elena; Timmermann, Lars

    2013-11-01

    Deep brain stimulation (DBS) has proven to be a successful therapeutic approach in several patients with movement disorders such as Parkinson's disease and dystonia. Hitherto its application was mainly restricted to advanced disease patients resistant to medication or with severe treatment side effects. However, there is now growing interest in earlier application of DBS, aimed at improving clinical outcomes, quality of life, and avoiding psychosocial consequences of chronic disease-related impairments. We address the clinical and ethical aspects of two "early" uses of DBS, (1) DBS early in the course of the disease, and (2) DBS early in life (i.e. in children). Possible benefits, risks and burdens are discussed and thoroughly considered. Further research is needed to obtain a careful balance between exposing vulnerable patients to potential severe surgical risks and excluding them from a potentially good outcome.

  5. Authenticity and autonomy in deep-brain stimulation.

    Science.gov (United States)

    Wardrope, Alistair

    2014-08-01

    Felicitas Kraemer draws on the experiences of patients undergoing deep-brain stimulation (DBS) to propose two distinct and potentially conflicting principles of respect: for an individual's autonomy (interpreted as mental competence), and for their authenticity. I argue instead that, according to commonly-invoked justifications of respect for autonomy, authenticity is itself in part constitutive of an analysis of autonomy worthy of respect; Kraemer's argument thus highlights the shortcomings of practical applications of respect for autonomy that emphasise competence while neglecting other important dimensions of autonomy such as authenticity, since it shows that competence alone cannot be interpreted as a reliable indicator of an individual's capacity for exercising autonomy. I draw from relational accounts to suggest how respect for a more expansive conception of autonomy might be interpreted for individuals undergoing DBS and in general.

  6. Moving Forward by Stimulating the Brain: Transcranial Direct Current Stimulation in Post-Stroke Hemiparesis.

    Science.gov (United States)

    Peters, Heather T; Edwards, Dylan J; Wortman-Jutt, Susan; Page, Stephen J

    2016-01-01

    Stroke remains a leading cause of disability worldwide, with a majority of survivors experiencing long term decrements in motor function that severely undermine quality of life. While many treatment approaches and adjunctive strategies exist to remediate motor impairment, many are only efficacious or feasible for survivors with active hand and wrist function, a population who constitute only a minority of stroke survivors. Transcranial direct current stimulation (tDCS), a type of non-invasive brain stimulation, has been increasingly utilized to increase motor function following stroke as it is able to be used with stroke survivors of varying impairment levels, is portable, is relatively inexpensive and has few side effects and contraindications. Accordingly, in recent years the number of studies investigating its efficacy when utilized as an adjunct to motor rehabilitation regimens has drastically increased. While many of these trials have reported positive and promising efficacy, methodologies vary greatly between studies, including differences in stimulation parameters, outcome measures and the nature of physical practice. As such, an urgent need remains, centering on the need to investigate these methodological differences and synthesize the most current evidence surrounding the application of tDCS for post-stroke motor rehabilitation. Accordingly, the purpose of this paper is to provide a detailed overview of the most recent tDCS literature (published 2014-2015), while highlighting these variations in methodological approach, as well to elucidate the mechanisms associated with tDCS and post-stroke motor re-learning and neuroplasticity.

  7. The Epistemology of Deep Brain Stimulation and Neuronal Pathophysiology

    Directory of Open Access Journals (Sweden)

    Erwin eMontgomery

    2012-09-01

    Full Text Available Deep Brain Stimulation (DBS is a remarkable therapy succeeding where all manner of pharmacological manipulations and brain transplants fail. The success of DBS has resurrected the relevance of electrophysiology and dynamics on the order of milliseconds. Despite the remarkable effects of DBS, its mechanisms of action are largely unknown. There has been an expanding catalogue of various neuronal and neural responses to DBS or DBS-like stimulation but no clear conceptual encompassing explanatory scheme has emerged despite the technological prowess and intellectual sophistication of the scientists involved. Something is amiss. If the scientific observations are sound, then why has there not been more progress? The alternative is that it may be the hypotheses that frame the questions are at fault as well as the methods of inference (logic used to validate the hypotheses. An analysis of the past and current notions of the DBS mechanisms of action is the subject in order to identify the presuppositions (premises and logical fallacies that may be at fault. The hope is that these problems will be avoided in the future so the DBS can realize its full potential quickly. In this regard, the discussion of the methods of inference and presuppositions that underlie many current notions is no different then a critique of experimental methods common in scientific discussions and consequently, examinations of the epistemology and logic are appropriate. This analysis is in keeping with the growing appreciation among scientists and philosophers of science, the scientific observations (data to not speak for themselves nor is the scientific method self-evidently true and that consideration of the underlying inferential methods is necessary.

  8. Deep brain stimulation: a return journey from psychiatry to neurology.

    Science.gov (United States)

    Ashkan, Keyoumars; Shotbolt, Paul; David, Anthony S; Samuel, Michael

    2013-06-01

    Deep brain stimulation (DBS) has emerged as an effective neurosurgical tool to treat a range of conditions. Its use in movement disorders such as Parkinson's disease, tremor and dystonia is now well established and has been approved by the National Institute of Clinical Excellence (NICE). The NICE does, however, emphasise the need for a multidisciplinary team to manage these patients. Such a team is traditionally composed of neurologists, neurosurgeons and neuropsychologists. Neuropsychiatrists, however, are increasingly recognised as essential members given many psychiatric considerations that may arise in patients undergoing DBS. Patient selection, assessment of competence to consent and treatment of postoperative psychiatric disease are just a few areas where neuropsychiatric input is invaluable. Partly driven by this close team working and partly based on the early history of DBS for psychiatric disorders, there is increasing interest in re-exploring the potential of neurosurgery to treat patients with psychiatric disease, such as depression and obsessive-compulsive disorder. Although the clinical experience and evidence with DBS in this group of patients are steadily increasing, many questions remain unanswered. Yet, the characteristics of optimal surgical candidates, the best choice of DBS target, the most effective stimulating parameters and the extent of postoperative improvement are not clear for most psychiatric conditions. Further research is therefore required to define how DBS can be best utilised to improve the quality of life of patients with psychiatric disease.

  9. Nootropic agents stimulate neurogenesis. Brain Cells, Inc.: WO2007104035.

    Science.gov (United States)

    Taupin, Philippe

    2009-05-01

    The application is in the field of adult neurogenesis, neural stem cells and cellular therapy. It aims to characterize the activity of nootropic agents on adult neurogenesis in vitro. Nootropic agents are substances improving cognitive and mental abilities. AMPA (alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate) and nootropic agents were assessed for the potential to differentiate human neural progenitor and stem cells into neuronal cells in vitro. They were also tested for their behavioural activity on the novel object recognition task. AMPA, piracetam, FK-960 and SGS-111 induce and stimulate neuronal differentiation of human-derived neural progenitor and stem cells. SGS-111 increases the number of visits to the novel object. The neurogenic activity of piracetam and SGS-111 is mediated through AMPA receptor. The neurogenic activity of SGS-111 may contribute and play a role in its nootropic activity. These results suggest that nootropic agents may elicit some of their effects through their neurogenic activity. The application claims the use of nootropic agents for their neurogenic activity and for the treatment of neurological diseases, disorders and injuries, by stimulating or increasing the generation of neuronal cells in the adult brain.

  10. Deep brain stimulation for severe autism: from pathophysiology to procedure.

    Science.gov (United States)

    Sinha, Saurabh; McGovern, Robert A; Sheth, Sameer A

    2015-06-01

    Autism is a heterogeneous neurodevelopmental disorder characterized by early-onset impairment in social interaction and communication and by repetitive, restricted behaviors and interests. Because the degree of impairment may vary, a spectrum of clinical manifestations exists. Severe autism is characterized by complete lack of language development and potentially life-threatening self-injurious behavior, the latter of which may be refractory to medical therapy and devastating for affected individuals and their caretakers. New treatment strategies are therefore needed. Here, the authors propose deep brain stimulation (DBS) of the basolateral nucleus of the amygdala (BLA) as a therapeutic intervention to treat severe autism. The authors review recent developments in the understanding of the pathophysiology of autism. Specifically, they describe the genetic and environmental alterations that affect neurodevelopment. The authors also highlight the resultant microstructural, macrostructural, and functional abnormalities that emerge during brain development, which create a pattern of dysfunctional neural networks involved in socioemotional processing. They then discuss how these findings implicate the BLA as a key node in the pathophysiology of autism and review a reported case of BLA DBS for treatment of severe autism. Much progress has been made in recent years in understanding the pathophysiology of autism. The BLA represents a logical neurosurgical target for treating severe autism. Further study is needed that considers mechanistic and operative challenges.

  11. Calcium imaging of infrared-stimulated activity in rodent brain.

    Science.gov (United States)

    Cayce, Jonathan Matthew; Bouchard, Matthew B; Chernov, Mykyta M; Chen, Brenda R; Grosberg, Lauren E; Jansen, E Duco; Hillman, Elizabeth M C; Mahadevan-Jansen, Anita

    2014-04-01

    Infrared neural stimulation (INS) is a promising neurostimulation technique that can activate neural tissue with high spatial precision and without the need for exogenous agents. However, little is understood about how infrared light interacts with neural tissue on a cellular level, particularly within the living brain. In this study, we use calcium sensitive dye imaging on macroscopic and microscopic scales to explore the spatiotemporal effects of INS on cortical calcium dynamics. The INS-evoked calcium signal that was observed exhibited a fast and slow component suggesting activation of multiple cellular mechanisms. The slow component of the evoked signal exhibited wave-like properties suggesting network activation, and was verified to originate from astrocytes through pharmacology and 2-photon imaging. We also provide evidence that the fast calcium signal may have been evoked through modulation of glutamate transients. This study demonstrates that pulsed infrared light can induce intracellular calcium modulations in both astrocytes and neurons, providing new insights into the mechanisms of action of INS in the brain.

  12. Biofouling resistance of boron-doped diamond neural stimulation electrodes is superior to titanium nitride electrodes in vivo

    Science.gov (United States)

    Meijs, S.; Alcaide, M.; Sørensen, C.; McDonald, M.; Sørensen, S.; Rechendorff, K.; Gerhardt, A.; Nesladek, M.; Rijkhoff, N. J. M.; Pennisi, C. P.

    2016-10-01

    Objective. The goal of this study was to assess the electrochemical properties of boron-doped diamond (BDD) electrodes in relation to conventional titanium nitride (TiN) electrodes through in vitro and in vivo measurements. Approach. Electrochemical impedance spectroscopy, cyclic voltammetry and voltage transient (VT) measurements were performed in vitro after immersion in a 5% albumin solution and in vivo after subcutaneous implantation in rats for 6 weeks. Main results. In contrast to the TiN electrodes, the capacitance of the BDD electrodes was not significantly reduced in albumin solution. Furthermore, BDD electrodes displayed a decrease in the VTs and an increase in the pulsing capacitances immediately upon implantation, which remained stable throughout the whole implantation period, whereas the opposite was the case for the TiN electrodes. Significance. These results reveal that BDD electrodes possess a superior biofouling resistance, which provides significantly stable electrochemical properties both in protein solution as well as in vivo compared to TiN electrodes.

  13. Simulation of 2D Brain's Potential Distribution Based on Two Electrodes ECVT Using Finite Element Method

    Science.gov (United States)

    Sirait, S. H.; Edison, R. E.; Baidillah, M. R.; Taruno, W. P.; Haryanto, F.

    2016-08-01

    The aim of this study is to simulate the potential distribution of 2D brain geometry based on two electrodes ECVT. ECVT (electrical capacitance tomography) is a tomography modality which produces dielectric distribution image of a subject from several capacitance electrodes measurements. This study begins by producing the geometry of 2D brain based on MRI image and then setting the boundary conditions on the boundaries of the geometry. The values of boundary conditions follow the potential values used in two electrodes brain ECVT, and for this reason the first boundary is set to 20 volt and 2.5 MHz signal and another boundary is set to ground. Poisson equation is implemented as the governing equation in the 2D brain geometry and finite element method is used to solve the equation. Simulated Hodgkin-Huxley action potential is applied as disturbance potential in the geometry. We divide this study into two which comprises simulation without disturbance potential and simulation with disturbance potential. From this study, each of time dependent potential distributions from non-disturbance and disturbance potential of the 2D brain geometry has been generated.

  14. The Safety of Using Body-Transmit MRI in Patients with Implanted Deep Brain Stimulation Devices.

    Directory of Open Access Journals (Sweden)

    Joshua Kahan

    Full Text Available Deep brain stimulation (DBS is an established treatment for patients with movement disorders. Patients receiving chronic DBS provide a unique opportunity to explore the underlying mechanisms of DBS using functional MRI. It has been shown that the main safety concern with MRI in these patients is heating at the electrode tips - which can be minimised with strict adherence to a supervised acquisition protocol using a head-transmit/receive coil at 1.5T. MRI using the body-transmit coil with a multi-channel receive head coil has a number of potential advantages including an improved signal-to-noise ratio.We compared the safety of cranial MRI in an in vitro model of bilateral DBS using both head-transmit and body-transmit coils. We performed fibre-optic thermometry at a Medtronic ActivaPC device and Medtronic 3389 electrodes during turbo-spin echo (TSE MRI using both coil arrangements at 1.5T and 3T, in addition to gradient-echo echo-planar fMRI exposure at 1.5T. Finally, we investigated the effect of transmit-coil choice on DBS stimulus delivery during MRI.Temperature increases were consistently largest at the electrode tips. Changing from head- to body-transmit coil significantly increased the electrode temperature elevation during TSE scans with scanner-reported head SAR 0.2W/kg from 0.45°C to 0.79°C (p<0.001 at 1.5T, and from 1.25°C to 1.44°C (p<0.001 at 3T. The position of the phantom relative to the body coil significantly impacted on electrode heating at 1.5T; however, the greatest heating observed in any position tested remained <1°C at this field strength.We conclude that (1 with our specific hardware and SAR-limited protocol, body-transmit cranial MRI at 1.5T does not produce heating exceeding international guidelines, even in cases of poorly positioned patients, (2 cranial MRI at 3T can readily produce heating exceeding international guidelines, (3 patients with ActivaPC Medtronic systems are safe to be recruited to future f

  15. Deep brain stimulation and cognitive decline in Parkinson's disease: The predictive value of electroencephalography.

    Science.gov (United States)

    Markser, A; Maier, Franziska; Lewis, C J; Dembek, T A; Pedrosa, D; Eggers, C; Timmermann, L; Kalbe, E; Fink, G R; Burghaus, Lothar

    2015-10-01

    Some Parkinson's disease (PD) patients treated with subthalamic nucleus deep brain stimulation (STN-DBS) develop new-onset cognitive decline. We examined whether clinical EEG recordings can be used to predict cognitive deterioration in PD patients undergoing STN-DBS. In this retrospective study, we used the Grand Total EEG (GTE)-score (short and total) to evaluate pre- and postoperative EEGs. In PD patients undergoing STN-DBS (N = 30), cognitive functioning was measured using Mini-Mental State Test and DemTect before and after surgery. Severity of motor impairment was assessed using the Unified Parkinson's Disease Rating Scale-III. Patients were classified into patients with or without cognitive decline after STN-DBS surgery. Epidemiological data, pre- and postoperative EEG recordings as well as neuropsychological and neurological data, electrode positions and the third ventricle width were compared. A logistic regression model was used to identify predictors of cognitive decline. Motor deficits significantly improved from pre- to post-surgery, while the mean GTE-scores increased significantly. Six patients developed cognitive deterioration 4-12 months postoperatively. These patients had significantly higher preoperative GTE-scores than patients without cognitive deterioration, although preoperative cognitive functioning was comparable. Electrode positions, brain atrophy and neurological data did not differ between groups. Logistic regression analysis identified the GTE-score as a significant predictor of postoperative cognitive deterioration. Data suggest that the preoperative GTE-score can be used to identify PD patients that are at high risk for developing cognitive deterioration after STN-DBS surgery even though their preoperative cognitive state was normal.

  16. Pedunculopontine Nucleus Region Deep Brain Stimulation in Parkinson Disease: Surgical Anatomy and Terminology

    Science.gov (United States)

    Hamani, Clement; Aziz, Tipu; Bloem, Bastiaan R.; Brown, Peter; Chabardes, Stephan; Coyne, Terry; Foote, Kelly; Garcia-Rill, Edgar; Hirsch, Etienne C.; Lozano, Andres M.; Mazzone, Paolo A.M.; Okun, Michael S.; Hutchison, William; Silburn, Peter; Zrinzo, Ludvic; Alam, Mesbah; Goetz, Laurent; Pereira, Erlick; Rughani, Anand; Thevathasan, Wesley; Moro, Elena; Krauss, Joachim K.

    2017-01-01

    Several lines of evidence over the last few years have been important in ascertaining that the pedunculopontine nucleus (PPN) region could be considered as a potential target for deep brain stimulation (DBS) to treat freezing and other problems as part of a spectrum of gait disorders in Parkinson disease and other akinetic movement disorders. Since the introduction of PPN DBS, a variety of clinical studies have been published. Most indicate improvements in freezing and falls in patients who are severely affected by these problems. The results across patients, however, have been variable, perhaps reflecting patient selection, heterogeneity in target selection and differences in surgical methodology and stimulation settings. Here we outline both the accumulated knowledge and the domains of uncertainty in surgical anatomy and terminology. Specific topics were assigned to groups of experts, and this work was accumulated and reviewed by the executive committee of the working group. Areas of disagreement were discussed and modified accordingly until a consensus could be reached. We demonstrate that both the anatomy and the functional role of the PPN region need further study. The borders of the PPN and of adjacent nuclei differ when different brainstem atlases and atlas slices are compared. It is difficult to delineate precisely the PPN pars dissipata from the nucleus cuneiformis, as these structures partially overlap. This lack of clarity contributes to the difficulty in targeting and determining the exact localization of the electrodes implanted in patients with akinetic gait disorders. Future clinical studies need to consider these issues. PMID:27723662

  17. Sputtered iridium oxide films (SIROFs) for low-impedance neural stimulation and recording electrodes.

    Science.gov (United States)

    Cogan, S F; Plante, T D; Ehrlich, J

    2004-01-01

    Iridium oxide films formed by electrochemical activation of iridium metal (AIROF) or by electrochemical deposition (EIROF) are being evaluated as low-impedance charge-injection coatings for neural stimulation and recording. Iridium oxide may also be deposited by reactive sputtering from iridium metal in an oxidizing plasma. The characterization of sputtered iridium oxide films (SIROFs) as coatings for nerve electrodes is reported. SIROFs were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and potential transient measurements during charge-injection. The surface morphology of the SIROF transitions from smooth to highly nodular with increasing film thickness from 80 nm to 4600 nm. Charge-injection capacities exceed 0.75 mC/cm(2) with 0.75 ms current pulses in thicker films. The SIROF was deposited on both planar and non-planar substrates and photolithographically patterned by lift-off.

  18. Effect of deep brain stimulation on substantia nigra neurons in a rat model of Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    WU Sheng-tian; MA Yu; ZHANG Kai; ZHANG Jian-guo

    2012-01-01

    Background Parkinson's disease(PD)is a common neurodegenerative disease,which occurs mainly in the elderly.Recent studies have demonstrated that apoptosis plays an important role in the occurrence and development of PD.Subthalamic nucleus deep brain stimulation(STN-DBS)has been recognized as an effective treatment for PD.Recent clinical observations have shown that STN-DBS was able to delay early PD progression,and experiments in animal models have also demonstrated a protective effect of STN-DBS on neurons.However,the correlation between the neuron-protective effect of STN-DBS and the progression of substantia nigra pars compacta(SNc)neuronal apoptosis is still unknown.The aim of this study was to investigate the protective effect and potential mechanism of STN-DBS on SNc neurons in PD rats.Methods After the establishment of a PD rat model by unilateral/2-point injection of 6-hydroxydopamine in the medial forebrain bundle of the brain,DBS by implanting electrodes in the STN was administered.Behavioral changes were observed,and morphological changes of SNc neurons were analyzed by Nissl staining and DNA in situ end-labeling.Through extracellular recording of single neuron discharges and microelectrophoresis,the causes of and changes in SNc excitability during STN-DBS were analyzed,and the protective effect and potential mechanism of action of STN-DBS on SNc neurons in PD rats was investigated.Results SNc neuron apoptosis was significantly decreased(P<0.05)in the stimulation group,compared with the sham stimulation PD group.Spontaneous discharges of SNc neurons were observed in normal rats and PD model rats,and the mean frequency of spontaneous discharges of SNc neurons in normal rats((40.65±11.08)Hz)was higher than that of residual SNc neurons in PD rats((36.71±9.23)Hz).Electrical stimulation of the STN in rats was associated with elevated excitation in unilateral SNc neurons.However,administering the gamma-aminobutyric acid receptor blocker

  19. Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging

    Science.gov (United States)

    Lemmens, Catherine; Montandon, Marie-Louise; Nuyts, Johan; Ratib, Osman; Dupont, Patrick; Zaidi, Habib

    2008-08-01

    The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of 18F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring.

  20. Two is More Than One: How to Combine Brain Stimulation Rehabilitative Training for Functional Recovery?

    Science.gov (United States)

    Koganemaru, Satoko; Fukuyama, Hidenao; Mima, Tatsuya

    2015-01-01

    A number of studies have shown that non-invasive brain stimulation has an additional effect in combination with rehabilitative therapy to enhance functional recovery than either therapy alone. The combination enhances use-dependent plasticity induced by repetitive training. The neurophysiological mechanism of the effects of this combination is based on associative plasticity. However, these effects were not reported in all cases. We propose a list of possible strategies to achieve an effective association between rehabilitative training with brain stimulation for plasticity: (1) control of temporal aspect between stimulation and task execution; (2) the use of a shaped task for the combination; (3) the appropriate stimulation of neuronal circuits where use-dependent plastic changes occur; and (4) phase synchronization between rhythmically patterned brain stimulation and task-related patterned activities of neurons. To better utilize brain stimulation in neuro-rehabilitation, it is important to develop more effective techniques to combine them.

  1. "Sexy stimulants": the interaction between psychomotor stimulants and sexual behavior in the female brain.

    Science.gov (United States)

    Guarraci, Fay A; Bolton, Jessica L

    2014-06-01

    Research indicates gender differences in sensitivity to psychomotor stimulants. Preclinical work investigating the interaction between drugs of abuse and sex-specific behaviors, such as sexual behavior, is critical to our understanding of such gender differences in humans. A number of behavioral paradigms can be used to model aspects of human sexual behavior in animal subjects. Although traditional assessment of the reflexive, lordosis posture of the female rat has been used to map the neuroanatomical and neurochemical systems that contribute to uniquely female copulatory behavior, the additional behavioral paradigms discussed in the current review have helped us expand our description of the appetitive and consummatory patterns of sexual behavior in the female rat. Measuring appetitive behavior is particularly important for assessing sexual motivation, the equivalent of "desire" in humans. By investigating the effects of commonly abused drugs on female sexual motivation, we are beginning to elucidate the role of dopaminergic neurotransmission, a neural system also known to be critical to the neurobiology of drug addiction, in female sexual motivation. A better understanding of the nexus of sex and drugs in the female brain will help advance our understanding of motivation in general and explain how psychomotor stimulants affect males and females differently.

  2. Hypothalamic deep brain stimulation reduces weight gain in an obesity-animal model.

    Directory of Open Access Journals (Sweden)

    William P Melega

    Full Text Available Prior studies of appetite regulatory networks, primarily in rodents, have established that targeted electrical stimulation of ventromedial hypothalamus (VMH can alter food intake patterns and metabolic homeostasis. Consideration of this method for weight modulation in humans with severe overeating disorders and morbid obesity can be further advanced by modeling procedures and assessing endpoints that can provide preclinical data on efficacy and safety. In this study we adapted human deep brain stimulation (DBS stereotactic methods and instrumentation to demonstrate in a large animal model the modulation of weight gain with VMH-DBS. Female Göttingen minipigs were used because of their dietary habits, physiologic characteristics, and brain structures that resemble those of primates. Further, these animals become obese on extra-feeding regimens. DBS electrodes were first bilaterally implanted into the VMH of the animals (n = 8 which were then maintained on a restricted food regimen for 1 mo following the surgery. The daily amount of food was then doubled for the next 2 mo in all animals to produce obesity associated with extra calorie intake, with half of the animals (n = 4 concurrently receiving continuous low frequency (50 Hz VMH-DBS. Adverse motoric or behavioral effects were not observed subsequent to the surgical procedure or during the DBS period. Throughout this 2 mo DBS period, all animals consumed the doubled amount of daily food. However, the animals that had received VMH-DBS showed a cumulative weight gain (6.1±0.4 kg; mean ± SEM that was lower than the nonstimulated VMH-DBS animals (9.4±1.3 kg; p<0.05, suggestive of a DBS-associated increase in metabolic rate. These results in a porcine obesity model demonstrate the efficacy and behavioral safety of a low frequency VMH-DBS application as a potential clinical strategy for modulation of body weight.

  3. Hypothalamic deep brain stimulation reduces weight gain in an obesity-animal model.

    Science.gov (United States)

    Melega, William P; Lacan, Goran; Gorgulho, Alessandra A; Behnke, Eric J; De Salles, Antonio A F

    2012-01-01

    Prior studies of appetite regulatory networks, primarily in rodents, have established that targeted electrical stimulation of ventromedial hypothalamus (VMH) can alter food intake patterns and metabolic homeostasis. Consideration of this method for weight modulation in humans with severe overeating disorders and morbid obesity can be further advanced by modeling procedures and assessing endpoints that can provide preclinical data on efficacy and safety. In this study we adapted human deep brain stimulation (DBS) stereotactic methods and instrumentation to demonstrate in a large animal model the modulation of weight gain with VMH-DBS. Female Göttingen minipigs were used because of their dietary habits, physiologic characteristics, and brain structures that resemble those of primates. Further, these animals become obese on extra-feeding regimens. DBS electrodes were first bilaterally implanted into the VMH of the animals (n = 8) which were then maintained on a restricted food regimen for 1 mo following the surgery. The daily amount of food was then doubled for the next 2 mo in all animals to produce obesity associated with extra calorie intake, with half of the animals (n = 4) concurrently receiving continuous low frequency (50 Hz) VMH-DBS. Adverse motoric or behavioral effects were not observed subsequent to the surgical procedure or during the DBS period. Throughout this 2 mo DBS period, all animals consumed the doubled amount of daily food. However, the animals that had received VMH-DBS showed a cumulative weight gain (6.1±0.4 kg; mean ± SEM) that was lower than the nonstimulated VMH-DBS animals (9.4±1.3 kg; p<0.05), suggestive of a DBS-associated increase in metabolic rate. These results in a porcine obesity model demonstrate the efficacy and behavioral safety of a low frequency VMH-DBS application as a potential clinical strategy for modulation of body weight.

  4. Comparison of dry and gel based electrodes for p300 brain-computer interfaces.

    Science.gov (United States)

    Guger, Christoph; Krausz, Gunther; Allison, Brendan Z; Edlinger, Guenter

    2012-01-01

    Most brain-computer interfaces (BCIs) rely on one of three types of signals in the electroencephalogram (EEG): P300s, steady-state visually evoked potentials, and event-related desynchronization. EEG is typically recorded non-invasively with electrodes mounted on the human scalp using conductive electrode gel for optimal impedance and data quality. The use of electrode gel entails serious problems that are especially pronounced in real-world settings when experts are not available. Some recent work has introduced dry electrode systems that do not require gel, but often introduce new problems such as comfort and signal quality. The principal goal of this study was to assess a new dry electrode BCI system in a very common task: spelling with a P300 BCI. A total of 23 subjects used a P300 BCI to spell the word "LUCAS" while receiving real-time, closed-loop feedback. The dry system yielded classification accuracies that were similar to those obtained with gel systems. All subjects completed a questionnaire after data recording, and all subjects stated that the dry system was not uncomfortable. This is the first field validation of a dry electrode P300 BCI system, and paves the way for new research and development with EEG recording systems that are much more practical and convenient in field settings than conventional systems.

  5. Comparison of dry and gel based electrodes for P300 brain-computer interfaces

    Directory of Open Access Journals (Sweden)

    Christoph eGuger

    2012-05-01

    Full Text Available Most brain-computer interfaces (BCI rely on one of three types of signals in the electroencephalogram (EEG: P300s, steady-state visually evoked potentials (SSVEP, and event-related desynchronization (ERD. EEG is typically recorded non-invasively with electrodes mounted on the human scalp using conductive electrode gel for optimal impedance and data quality. The use of electrode gel entails serious problems that are especially pronounced in real-world settings when experts are not available. Some recent work has introduced dry electrode systems that do not require gel, but often introduce new problems such as comfort and signal quality. The principal goal of this study was to assess a new dry electrode BCI system in a very common task: spelling with a P300 BCI. A total of 23 subjects used a P300 BCI to spell the word LUCAS while receiving realtime, closed-loop feedback. The dry system yielded classification accuracies that were similar to those obtained with gel systems. All subjects completed a questionnaire after data recording, and all subjects stated that the dry system was not uncomfortable. This is the first field validation of a dry electrode P300 BCI system, and paves the way for new research and development with EEG recording systems that are much more practical and convenient in field settings than conventional systems.

  6. A split microdrive for simultaneous multi-electrode recordings from two brain areas in awake small animals.

    NARCIS (Netherlands)

    C.S. Lansink; M. Bakker; W. Buster; J. Lankelma; R. van der Blom; R. Westdorp; R.N.J.M.A. Joosten; B.L. Mc.Naughton; C.M.A. Pennartz

    2007-01-01

    Complex cognitive operations such as memory formation and decision-making are thought to be mediated not by single, isolated brain structures but by multiple, connected brain areas. To facilitate studies on the neural communication between connected brain structures, we developed a multi-electrode m

  7. High-Frequency Deep Brain Stimulation of the Putamen Improves Bradykinesia in Parkinson’s Disease

    Science.gov (United States)

    Montgomery, Erwin B.; Huang, He; Walker, Harrison C.; Guthrie, Barton L.; Watts, Ray L.

    2014-01-01

    Deep brain stimulation is effective for a wide range of neurological disorders; however, its mechanisms of action remain unclear. With respect to Parkinson’s disease, the existence of multiple effective targets suggests that putamen stimulation also may be effective and raises questions as to the mechanisms of action. Are there as many mechanisms of action as there are effective targets or some single or small set of mechanisms common to all effective targets? During the course of routine surgery of the globus pallidus interna in patients with Parkinson’s disease, the deep brain stimulation lead was placed in the putamen en route to the globus pallidus interna. Recordings of hand opening and closing during high-frequency and no stimulation were made. Speed of the movements, based on the amplitude and frequency of the repetitive hand movements as well as the decay in amplitude, were studied. Hand speed in 6 subjects was statistically significantly faster during active deep brain stimulation than the no-stimulation condition. There were no statistically significant differences in decay in the amplitude of hand movements. High-frequency deep brain stimulation of the putamen improves bradykinesia in a hand-opening and -closing task in patients with Parkinson’s disease. Consequently, high-frequency deep brain stimulation of virtually every structure in the basal ganglia-thalamic-cortical system improves bradykinesia. These observations, together with microelectrode recordings reported in the literature, argue that deep brain stimulation effects may be system specific and not structure specific. PMID:21714010

  8. Guiding transcranial brain stimulation by EEG/MEG to interact with ongoing brain activity and associated functions

    DEFF Research Database (Denmark)

    Thut, Gregor; Bergmann, Til Ole; Fröhlich, Flavio

    2017-01-01

    Non-invasive transcranial brain stimulation (NTBS) techniques have a wide range of applications but also suffer from a number of limitations mainly related to poor specificity of intervention and variable effect size. These limitations motivated recent efforts to focus on the temporal dimension...... of NTBS with respect to the ongoing brain activity. Temporal patterns of ongoing neuronal activity, in particular brain oscillations and their fluctuations, can be traced with electro- or magnetoencephalography (EEG/MEG), to guide the timing as well as the stimulation settings of NTBS. These novel, online...... and offline EEG/MEG-guided NTBS-approaches are tailored to specifically interact with the underlying brain activity. Online EEG/MEG has been used to guide the timing of NTBS (i.e., when to stimulate): by taking into account instantaneous phase or power of oscillatory brain activity, NTBS can be aligned...

  9. Pulse electrical arc stimulator based on single-electrode for active exercise in tail-suspension rat

    Institute of Scientific and Technical Information of China (English)

    孙联文; 谢添; 樊瑜波; 张晓薇; 孙瑶; 杨肖

    2008-01-01

    To make rat do active exercise to counteract bone loss in the rat tail-suspension model, a pulse electrical stimulator based on single-electrode with a low-current and a high-voltage was designed. The stimulator was controlled by SCM (single chip micyoco) that could accurately control the stimulation duration and the interval between stimulations, and cease the operation after the recorded number of stimulation had reached the value set by the program. With the help of posture estimation part, the device would operate intelligently by determining whether to stimulate or not, depending on the posture of rat’s limb. Software was developed to make operator control the stimulator using computer, save the experiment data and print the report. In practical experiment, the voltaic arc is generated by the stimulator, and impacted on the rat’s thenar. This induced pain to the rat and the rat would actively contract its hindlimb to evade the pain, so active exercise was carried out. The tail-suspension rats were trained twice every day for 14 d. At the 0 and 14th day, bone mineral density of rat femurs was determined by dual energy X-ray absorptiometry (DXA). The results show that the active exercise stimulated by the pulse electrical arc stimulator can attenuate weightlessness-induced bone loss, and this device is a convenient steady performance electrical stimulator that can surely induce rat’s hindlimb to do active exercise.

  10. Modulating presence and impulsiveness by external stimulation of the brain

    Directory of Open Access Journals (Sweden)

    Baumgartner Thomas

    2008-08-01

    Full Text Available Abstract Background "The feeling of being there" is one possible way to describe the phenomenon of feeling present in a virtual environment and to act as if this environment is real. One brain area, which is hypothesized to be critically involved in modulating this feeling (also called presence is the dorso-lateral prefrontal cortex (dlPFC, an area also associated with the control of impulsive behavior. Methods In our experiment we applied transcranial direct current stimulation (tDCS to the right dlPFC in order to modulate the experience of presence while watching a virtual roller coaster ride. During the ride we also registered electro-dermal activity. Subjects also performed a test measuring impulsiveness and answered a questionnaire about their presence feeling while they were exposed to the virtual roller coaster scenario. Results Application of cathodal tDCS to the right dlPFC while subjects were exposed to a virtual roller coaster scenario modulates the electrodermal response to the virtual reality stimulus. In addition, measures reflecting impulsiveness were also modulated by application of cathodal tDCS to the right dlPFC. Conclusion Modulating the activation with the right dlPFC results in substantial changes in responses of the vegetative nervous system and changed impulsiveness. The effects can be explained by theories discussing the top-down influence of the right dlPFC on the "impulsive system".

  11. Personality Changes after Deep Brain Stimulation in Parkinson's Disease

    Science.gov (United States)

    Pham, Uyen; Solbakk, Anne-Kristin; Skogseid, Inger-Marie; Pripp, Are Hugo; Konglund, Ane Eidahl; Andersson, Stein; Haraldsen, Ira Ronit; Aarsland, Dag; Dietrichs, Espen; Malt, Ulrik Fredrik

    2015-01-01

    Objectives. Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a recognized therapy that improves motor symptoms in advanced Parkinson's disease (PD). However, little is known about its impact on personality. To address this topic, we have assessed personality traits before and after STN-DBS in PD patients. Methods. Forty patients with advanced PD were assessed with the Temperament and Character Inventory (TCI): the Urgency, Premeditation, Perseverance, Sensation Seeking impulsive behaviour scale (UPPS), and the Neuroticism and Lie subscales of the Eysenck Personality Questionnaire (EPQ-N, EPQ-L) before surgery and after three months of STN-DBS. Collateral information obtained from the UPPS was also reported. Results. Despite improvement in motor function and reduction in dopaminergic dosage patients reported lower score on the TCI Persistence and Self-Transcendence scales, after three months of STN-DBS, compared to baseline (P = 0.006; P = 0.024). Relatives reported significantly increased scores on the UPPS Lack of Premeditation scale at follow-up (P = 0.027). Conclusion. STN-DBS in PD patients is associated with personality changes in the direction of increased impulsivity. PMID:25705545

  12. Ipsilateral motor pathways after stroke: implications for noninvasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Lynley V Bradnam

    2013-05-01

    Full Text Available In humans the two cerebral hemispheres have essential roles in controlling the upper limb. The purpose of this article is to draw attention to the potential importance of ipsilateral descending pathways for functional recovery after stroke, and the use of noninvasive brain stimulation (NBS protocols of the contralesional primary motor cortex (M1. Conventionally NBS is used to suppress contralesional M1, and to attenuate transcallosal inhibition onto the ipsilesional M1. There has been little consideration of the fact that contralesional M1 suppression may also reduce excitability of ipsilateral descending pathways that may be important for paretic upper limb control for some patients. One such ipsilateral pathway is the cortico-reticulo-propriospinal pathway (CRPP. In this review we outline a neurophysiological model to explain how contralesional M1 may gain control of the paretic arm via the CRPP. We conclude that the relative importance of the CRPP for motor control in individual patients must be considered before using NBS to suppress contralesional M1. Neurophysiological, neuroimaging and clinical assessments can assist this decision making and facilitate the translation of NBS into the clinical setting.

  13. Increasing infection rate in multiple implanted pulse generator changes in movement disorder patients treated with deep brain stimulation

    DEFF Research Database (Denmark)

    Thrane, Jens F; Sunde, Niels A; Bergholt, Bo

    2014-01-01

    Increasing infection rate in multiple implanted pulse generator changes in movement disorder patients treated with deep brain stimulation......Increasing infection rate in multiple implanted pulse generator changes in movement disorder patients treated with deep brain stimulation...

  14. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task.

    Science.gov (United States)

    Laubacher, Marco; Aksöz, Efe A; Binder-Macleod, Stuart; Hunt, Kenneth J

    2016-06-13

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable.

  15. Analysis of Magnetic Field Inducted in Brain by Multi-Channel Magnetic Stimulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Multi-channel magnetic stimulation is an efficient method to improve the conventional magnetic stimulation. A multi-channel magnetic brain stimulator was developed and the distribution of magnetic field was calculated by finite-element analysis software-ANSYS. The results show that when five coils work simultaneously, the area where the magnetic flux density is larger than 0.01 T would expand to almost the whole brain region, and the magnetic stimulation depth would be improved.Experiments were performed on ten subjects (mean age 25) using the stimulator, and the EEG power spectrums before and after stimulation were analyzed. The experimental results show that the beta component of EEG obviously increases after magnetic stimulation, and the effect is more obvious by using more coils simultaneously because of the deeper stimulation.

  16. Non-invasive brain stimulation of the aging brain: State of the art and future perspectives.

    Science.gov (United States)

    Tatti, Elisa; Rossi, Simone; Innocenti, Iglis; Rossi, Alessandro; Santarnecchi, Emiliano

    2016-08-01

    Favored by increased life expectancy and reduced birth rate, worldwide demography is rapidly shifting to older ages. The golden age of aging is not only an achievement but also a big challenge because of the load of the elderly on social and medical health care systems. Moreover, the impact of age-related decline of attention, memory, reasoning and executive functions on self-sufficiency emphasizes the need of interventions to maintain cognitive abilities at a useful degree in old age. Recently, neuroscientific research explored the chance to apply Non-Invasive Brain Stimulation (NiBS) techniques (as transcranial electrical and magnetic stimulation) to healthy aging population to preserve or enhance physiologically-declining cognitive functions. The present review will update and address the current state of the art on NiBS in healthy aging. Feasibility of NiBS techniques will be discussed in light of recent neuroimaging (either structural or functional) and neurophysiological models proposed to explain neural substrates of the physiologically aging brain. Further, the chance to design multidisciplinary interventions to maximize the efficacy of NiBS techniques will be introduced as a necessary future direction.

  17. Three-dimensional brain reconstruction of in vivo electrode tracks for neuroscience and neural prosthetic applications

    Directory of Open Access Journals (Sweden)

    Craig D. Markovitz

    2012-06-01

    Full Text Available The brain is a densely interconnected network that relies on populations of neurons within and across multiple nuclei to code for features leading to perception and action. However, the neurophysiology field is still dominated by the characterization of individual neurons, rather than simultaneous recordings across multiple regions, without consistent spatial reconstruction of their locations for comparisons across studies. There are sophisticated histological and imaging techniques for performing brain reconstructions. However, what is needed is a method that is relatively easy and inexpensive to implement in a typical neurophysiology lab and provides consistent identification of electrode locations to make it widely used for pooling data across studies and research groups. This paper presents our initial development of such an approach for reconstructing electrode tracks and site locations within the guinea pig inferior colliculus (IC to identify its functional organization for frequency coding relevant for a new auditory midbrain implant. Encouragingly, the spatial error associated with different individuals reconstructing electrode tracks for the same midbrain was less than 65 µm, corresponding to an error of ~1.5% relative to the entire IC structure (~4-5 mm diameter sphere. Furthermore, the reconstructed frequency laminae of the IC were consistently aligned across three sampled midbrains, demonstrating the ability to use our method to combine location data across animals. Hopefully, through further improvements in our reconstruction method, it can be used as a standard protocol across neurophysiology labs to characterize neural data not only within the IC but also within other brain regions to help bridge the gap between cellular activity and network function. Clinically, correlating function with location within and across multiple brain regions can guide optimal placement of electrodes for the growing field of neural prosthetics.

  18. [Non-invasive brain stimulation in neurology : Transcranial direct current stimulation to enhance cognitive functioning].

    Science.gov (United States)

    Antonenko, D; Flöel, A

    2016-08-01

    Transcranial direct current stimulation (tDCS) has been successfully used in neuroscientific research to modulate cognitive functions. Recent studies suggested that improvement of behavioral performance is associated with tDCS-induced modulation of neuronal activity and connectivity. Thus, tDCS may also represent a promising tool for reconstitution of cognitive functions in the context of memory decline related to Alzheimer's disease or aphasia following stroke; however, evidence from randomized sham-controlled clinical trials is still scarce. Initial results of tDCS-induced behavioral improvement in patients with Alzheimer's dementia and its precursors indicated that an intense memory training combined with tDCS may be effective. Early interventions in the stage of mild cognitive impairment could be crucial but further evidence is needed to substantiate this. In patients with aphasia following stroke tDCS was applied to the left and right hemispheres, with varying results depending on the severity of the symptoms and polarity of the stimulation. Patients with mild aphasia can benefit from tDCS of the language dominant hemisphere while in patients with severe aphasia tDCS of right hemispheric homologous brain language areas may be particularly relevant. Moreover, recent studies suggested that an intervention in the subacute phase of aphasia could be most promising. In summary, tDCS could provide the exciting possibility to reconstitute cognitive functions in patients with neurological disorders. Future studies have to elucidate whether tDCS can be used in the clinical routine to prevent further cognitive decline in neurodegenerative diseases and whether beneficial effects from experimental studies translate into long-term improvement in activities of daily life.

  19. Clinical application of peroneal nerve stimulator system using percutaneous intramuscular electrodes for correction of foot drop in hemiplegic patients.

    Science.gov (United States)

    Shimada, Yoichi; Matsunaga, Toshiki; Misawa, Akiko; Ando, Shigeru; Itoi, Eiji; Konishi, Natsuo

    2006-10-01

    Objective.  To assess the orthotic effect of a functional electrical stimulation device (Akita Heel Sensor System; AHSS) in the treatment of hemiplegic gait with foot drop. Materials and Methods.  In the AHSS, a heel sensor is attached to a small plastic heel brace, and the peroneal nerve is stimulated via percutaneous intramuscular electrodes. During the swing phase of the hemiplegic gait, the common peroneal nerve is stimulated by the AHSS. Eight patients in chronic stages of hemiplegia participated in this study. Walking speeds and step cadences on a 10-m course were compared between walking with stimulation and walking without stimulation. Results.  Mean walking speed (± SD) was 0.50 ± 0.26 m/sec without stimulation and 0.64 ± 0.31 m/sec with stimulation. The mean percentage increase in walking speed with stimulation was 30.1%. Mean step cadence was 31 ± 7 steps/10 m without stimulation and 27 ± 7 steps/10 m with stimulation. By correcting foot drop, the AHSS significantly increased walking speed and decreased cadence (p AHSS can significantly improve walking in hemiplegic patients with foot drop.

  20. Inter-subject and Inter-session Variability of Plasticity Induction by Non-invasive Brain Stimulation

    DEFF Research Database (Denmark)

    Ziemann, Ulf; Siebner, Hartwig R

    2015-01-01

    Non-invasive brain stimulation (NIBS) protocols such as regular repetitive transcranial magnetic stimulation (rTMS), theta-burst stimulation (TBS), paired associative stimulation (PAS) and transcranial direct current stimulation (tDCS) can change the excitability of the stimulated neuronal network...

  1. Validating computationally predicted TMS stimulation areas using direct electrical stimulation in patients with brain tumors near precentral regions

    Directory of Open Access Journals (Sweden)

    Alexander Opitz

    2014-01-01

    Full Text Available The spatial extent of transcranial magnetic stimulation (TMS is of paramount interest for all studies employing this method. It is generally assumed that the induced electric field is the crucial parameter to determine which cortical regions are excited. While it is difficult to directly measure the electric field, one usually relies on computational models to estimate the electric field distribution. Direct electrical stimulation (DES is a local brain stimulation method generally considered the gold standard to map structure–function relationships in the brain. Its application is typically limited to patients undergoing brain surgery. In this study we compare the computationally predicted stimulation area in TMS with the DES area in six patients with tumors near precentral regions. We combine a motor evoked potential (MEP mapping experiment for both TMS and DES with realistic individual finite element method (FEM simulations of the electric field distribution during TMS and DES. On average, stimulation areas in TMS and DES show an overlap of up to 80%, thus validating our computational physiology approach to estimate TMS excitation volumes. Our results can help in understanding the spatial spread of TMS effects and in optimizing stimulation protocols to more specifically target certain cortical regions based on computational modeling.

  2. Validating computationally predicted TMS stimulation areas using direct electrical stimulation in patients with brain tumors near precentral regions.

    Science.gov (United States)

    Opitz, Alexander; Zafar, Noman; Bockermann, Volker; Rohde, Veit; Paulus, Walter

    2014-01-01

    The spatial extent of transcranial magnetic stimulation (TMS) is of paramount interest for all studies employing this method. It is generally assumed that the induced electric field is the crucial parameter to determine which cortical regions are excited. While it is difficult to directly measure the electric field, one usually relies on computational models to estimate the electric field distribution. Direct electrical stimulation (DES) is a local brain stimulation method generally considered the gold standard to map structure-function relationships in the brain. Its application is typically limited to patients undergoing brain surgery. In this study we compare the computationally predicted stimulation area in TMS with the DES area in six patients with tumors near precentral regions. We combine a motor evoked potential (MEP) mapping experiment for both TMS and DES with realistic individual finite element method (FEM) simulations of the electric field distribution during TMS and DES. On average, stimulation areas in TMS and DES show an overlap of up to 80%, thus validating our computational physiology approach to estimate TMS excitation volumes. Our results can help in understanding the spatial spread of TMS effects and in optimizing stimulation protocols to more specifically target certain cortical regions based on computational modeling.

  3. OPTIMAL REPRESENTATION OF MER SIGNALS APPLIED TO THE IDENTIFICATION OF BRAIN STRUCTURES DURING DEEP BRAIN STIMULATION

    Directory of Open Access Journals (Sweden)

    Hernán Darío Vargas Cardona

    2015-07-01

    Full Text Available Identification of brain signals from microelectrode recordings (MER is a key procedure during deep brain stimulation (DBS applied in Parkinson’s disease patients. The main purpose of this research work is to identify with high accuracy a brain structure called subthalamic nucleus (STN, since it is the target structure where the DBS achieves the best therapeutic results. To do this, we present an approach for optimal representation of MER signals through method of frames. We obtain coefficients that minimize the Euclidean norm of order two. From optimal coefficients, we extract some features from signals combining the wavelet packet and cosine dictionaries. For a comparison frame with the state of the art, we also process the signals using the discrete wavelet transform (DWT with several mother functions. We validate the proposed methodology in a real data base. We employ simple supervised machine learning algorithms, as the K-Nearest Neighbors classifier (K-NN, a linear Bayesian classifier (LDC and a quadratic Bayesian classifier (QDC. Classification results obtained with the proposed method improves significantly the performance of the DWT. We achieve a positive identification of the STN superior to 97,6%. Identification outcomes achieved by the MOF are highly accurate, as we can potentially get a false positive rate of less than 2% during the DBS.

  4. Early Brain Stimulation May Help Stroke Survivors Recover Language Function

    Science.gov (United States)

    ... survivors with several types of aphasia at the rehabilitation hospital Rehanova and the Max-Planck-Institute for neurological research in Cologne, Germany. Thirteen received transcranial magnetic stimulation (TMS) and 11 got sham stimulation. The TMS ...

  5. Effect of subthalamic deep brain stimulation on pain in Parkinson's disease.

    Science.gov (United States)

    Dellapina, Estelle; Ory-Magne, Fabienne; Regragui, Wafa; Thalamas, Claire; Lazorthes, Yves; Rascol, Olivier; Payoux, Pierre; Brefel-Courbon, Christine

    2012-11-01

    Painful sensations are common in Parkinson's disease. In many patients, such sensations correspond to neuropathic pain and could be related to central alterations of pain processing. Subthalamic nuclei deep brain stimulation improves motor function in Parkinson's disease. Several structures of the basal ganglia are involved in nociceptive function, and deep brain stimulation could thus also modify pain perception in Parkinson's disease. To test this hypothesis, we compared subjective heat pain thresholds, in deep brain stimulation OFF and ON conditions in 2 groups of Parkinson's disease patients with or without neuropathic pain. We also compared pain-induced cerebral activations during experimental nociceptive stimulations using H(2)(15)O positron emission tomography in both deep brain stimulation OFF and ON conditions. Correlation analyses were performed between clinical and neuroimaging results. Deep brain stimulation significantly increased subjective heat pain threshold (from 40.3 ± 4.2 to 41.6 ± 4.3, P=.03) and reduced pain-induced cerebral activity in the somatosensory cortex (BA 40) in patients with pain, whereas it had no effect in pain-free patients. There was a significant negative correlation in the deep brain stimulation OFF condition between pain threshold and pain-induced activity in the insula of patients who were pain free but not in those who had pain. There was a significant positive correlation between deep brain stimulation-induced changes in pain threshold and in pain-induced cerebral activations in the primary somatosensory cortex and insula of painful patients only. These results suggest that subthalamic nuclei deep brain stimulation raised pain thresholds in Parkinson's disease patients with pain and restored better functioning of the lateral discriminative pain system.

  6. Neuroplasticity in post-stroke gait recovery and noninvasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Yi Xu

    2015-01-01

    Full Text Available Gait disorders drastically affect the quality of life of stroke survivors, making post-stroke rehabilitation an important research focus. Noninvasive brain stimulation has potential in facilitating neuroplasticity and improving post-stroke gait impairment. However, a large inter-individual variability in the response to noninvasive brain stimulation interventions has been increasingly recognized. We first review the neurophysiology of human gait and post-stroke neuroplasticity for gait recovery, and then discuss how noninvasive brain stimulation techniques could be utilized to enhance gait recovery. While post-stroke neuroplasticity for gait recovery is characterized by use-dependent plasticity, it evolves over time, is idiosyncratic, and may develop maladaptive elements. Furthermore, noninvasive brain stimulation has limited reach capability and is facilitative-only in nature. Therefore, we recommend that noninvasive brain stimulation be used adjunctively with rehabilitation training and other concurrent neuroplasticity facilitation techniques. Additionally, when noninvasive brain stimulation is applied for the rehabilitation of gait impairment in stroke survivors, stimulation montages should be customized according to the specific types of neuroplasticity found in each individual. This could be done using multiple mapping techniques.

  7. Resting state functional MRI in Parkinson's disease: the impact of deep brain stimulation on 'effective' connectivity.

    Science.gov (United States)

    Kahan, Joshua; Urner, Maren; Moran, Rosalyn; Flandin, Guillaume; Marreiros, Andre; Mancini, Laura; White, Mark; Thornton, John; Yousry, Tarek; Zrinzo, Ludvic; Hariz, Marwan; Limousin, Patricia; Friston, Karl; Foltynie, Tom

    2014-04-01

    Depleted of dopamine, the dynamics of the parkinsonian brain impact on both 'action' and 'resting' motor behaviour. Deep brain stimulation has become an established means of managing these symptoms, although its mechanisms of action remain unclear. Non-invasive characterizations of induced brain responses, and the effective connectivity underlying them, generally appeals to dynamic causal modelling of neuroimaging data. When the brain is at rest, however, this sort of characterization has been limited to correlations (functional connectivity). In this work, we model the 'effective' connectivity underlying low frequency blood oxygen level-dependent fluctuations in the resting Parkinsonian motor network-disclosing the distributed effects of deep brain stimulation on cortico-subcortical connections. Specifically, we show that subthalamic nucleus deep brain stimulation modulates all the major components of the motor cortico-striato-thalamo-cortical loop, including the cortico-striatal, thalamo-cortical, direct and indirect basal ganglia pathways, and the hyperdirect subthalamic nucleus projections. The strength of effective subthalamic nucleus afferents and efferents were reduced by stimulation, whereas cortico-striatal, thalamo-cortical and direct pathways were strengthened. Remarkably, regression analysis revealed that the hyperdirect, direct, and basal ganglia afferents to the subthalamic nucleus predicted clinical status and therapeutic response to deep brain stimulation; however, suppression of the sensitivity of the subthalamic nucleus to its hyperdirect afferents by deep brain stimulation may subvert the clinical efficacy of deep brain stimulation. Our findings highlight the distributed effects of stimulation on the resting motor network and provide a framework for analysing effective connectivity in resting state functional MRI with strong a priori hypotheses.

  8. Prolonged repeated acupuncture stimulation induces habituation effects in pain-related brain areas: an FMRI study.

    Science.gov (United States)

    Li, Chuanfu; Yang, Jun; Park, Kyungmo; Wu, Hongli; Hu, Sheng; Zhang, Wei; Bu, Junjie; Xu, Chunsheng; Qiu, Bensheng; Zhang, Xiaochu

    2014-01-01

    Most previous studies of brain responses to acupuncture were designed to investigate the acupuncture instant effect while the cumulative effect that should be more important in clinical practice has seldom been discussed. In this study, the neural basis of the acupuncture cumulative effect was analyzed. For this experiment, forty healthy volunteers were recruited, in which more than 40 minutes of repeated acupuncture stimulation was implemented at acupoint Zhusanli (ST36). Three runs of acupuncture fMRI datasets were acquired, with each run consisting of two blocks of acupuncture stimulation. Besides general linear model (GLM) analysis, the cumulative effects of acupuncture were analyzed with analysis of covariance (ANCOVA) to find the association between the brain response and the cumulative duration of acupuncture stimulation in each stimulation block. The experimental results showed that the brain response in the initial stage was the strongest although the brain response to acupuncture was time-variant. In particular, the brain areas that were activated in the first block and the brain areas that demonstrated cumulative effects in the course of repeated acupuncture stimulation overlapped in the pain-related areas, including the bilateral middle cingulate cortex, the bilateral paracentral lobule, the SII, and the right thalamus. Furthermore, the cumulative effects demonstrated bimodal characteristics, i.e. the brain response was positive at the beginning, and became negative at the end. It was suggested that the cumulative effect of repeated acupuncture stimulation was consistent with the characteristic of habituation effects. This finding may explain the neurophysiologic mechanism underlying acupuncture analgesia.

  9. Body weight gain rate in patients with Parkinson's disease and deep brain stimulation.

    Science.gov (United States)

    Barichella, Michela; Marczewska, Agnieszka M; Mariani, Claudio; Landi, Andrea; Vairo, Antonella; Pezzoli, Gianni

    2003-11-01

    We evaluated body weight changes in patients with Parkinson's disease (PD) after electrode implantation for deep brain stimulation (DBS) in the subthalamic nucleus (STN) in relation to clinical improvement. Thirty PD patients who received STN DBS were included (22 men, 8 women; mean age, 60.0 +/- 7.1 years; mean PD duration, 13.5 +/- 3.7 years; mean body mass index [BMI], 21.6 +/- 3.0 kg/m2). Body weight, physical activity, and Unified Parkinson's Disease Rating Scale (UPDRS) scores were noted before and 3 and 12 months after the procedure. Significant weight gain occurred in 29 patients; the mean increase was 14.8 +/- 9.8% of initial body weight in 1 year. Of the patients, 46.5% reported weight gain in the first 3 months, 21.4% gradual weight gain in the first 6 months, and 32.1% a slow increase for 1 year. Mean BMI increased up to 24.7 +/- 3.7 kg/m2. After 1 year, mean UPDRS motor score improved significantly in off and in on; and therapy complications improved by 91.0 +/- 17.0%. BMI changes at 3 and 12 months were significantly correlated to dyskinesia score changes, and levodopa dosage was not. In PD, STN DBS produces not only symptom control, but also weight gain. DBS candidates should be given nutritional counseling before the intervention to prevent rapid and/or excessive weight gain.

  10. 脑深部神经刺激微电极的表面改性研究%Surface Modification of Microelectrode for Deep Brain Stimulation

    Institute of Scientific and Technical Information of China (English)

    白宗旭; 刘亚雄; 王会友; 丁玉成

    2011-01-01

    To improve the biocompatibility of micro-electrode for deep brain stimulation (DBS), and to reduce the immune response of brain tissue and thick encapsulation layer surround the electrode , a surface modification was executed on the polyurethane of DBS electrode head. The electrode surface firstly was modified by N2/H2 plasma treatments to achieve the active amino group, and then the polypeptide molecule YIGSR was endowed by a polymerization with the amino group on the electrode surface, consequently, the electrode surface had a layer of polypeptide molecule promoting nerve cell growth. The experiment results of modified electrode implant in rat brain confirm that to a certain degree, the modified electrode can reduce the thick encapsulation layer surround the electrode, it is beneficial for contact between electrode and never cells, and the electrode can make a bigger volume of tissue activated. The grafting large-molecule polymer on the polyurethane surface is feasible, and the conclusion gets referable for the further research on bio-electrode surface modification.%为了提高脑深部刺激电极的生物相容性,降低脑组织的免疫反应,减少或抑制电极周围包裹物的形成,对电极植入端聚氨酯材料进行了表面改性处理.首先用N2/H2进行等离子体处理,在电极表面生成活性基团——氨基,再利用电极表面的氨基基团与YIGSR多肽分子发生聚合反应,从而实现在电极表面修饰上对神经细胞具有促进生长作用的多肽分子.改性电极的大鼠植入实验结果发现,改性电极能够在一定程度上减少胶质包裹物的形成,有利于电极与神经细胞之间接触,增加有效刺激体积,证明了电极聚氨酯材料表面接枝聚合生物大分子的可行性,对今后电极表面改性的深入研究具有一定的参考意义.

  11. Neuroprotective effects of vagus nerve stimulation on traumatic brain injur y

    Institute of Scientific and Technical Information of China (English)

    Long Zhou; Jinhuang Lin; Junming Lin; Guoju Kui; Jianhua Zhang; Yigang Yu

    2014-01-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of trau-matic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain ex-plosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1βand interleukin-10 concentrations were detected in serum and brain tissues, and water content in brain tissues was measured. Results showed that vagus nerve stimulation could reduce the degree of brain edema, decrease tumor necrosis factor-αand interleukin-1βconcentrations, and increase interleukin-10 concentration after brain explosive injury in rabbits. These data suggest that vagus nerve stimulation may exert neuroprotective effects against explosive injury via regulating the expression of tumor necrosis factor-α, interleukin-1βand interleukin-10 in the serum and brain tissue.

  12. High frequency deep brain stimulation attenuates subthalamic and cortical rhythms in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Diane eWhitmer

    2012-06-01

    Full Text Available Parkinson’s disease (PD is marked by excessive synchronous activity in the beta (8-35 Hz band throughout the cortico-basal ganglia network. The optimal location of high frequency deep brain stimulation (HF DBS within the subthalamic nucleus (STN region and the location of maximal beta hypersynchrony are currently matters of debate. Additionally, the effect of STN HF DBS on neural synchrony in functionally connected regions of motor cortex is unknown and of great interest. Scalp EEG studies demonstrated that stimulation of the STN can activate motor cortex antidromically, but the spatial specificity of this effect has not been examined. The present study examined the effect of STN HF DBS on neural synchrony within the cortico-basal ganglia network in patients with PD. We measured local field potentials dorsal to and within the STN of PD patients, and additionally in the motor cortex in a subset of these patients. We used diffusion tensor imaging (DTI to guide the placement of subdural cortical surface electrodes over the DTI-identified origin of the hyperdirect pathway between motor cortex and the STN. The results demonstrated that local beta power was attenuated during HF DBS both dorsal to and within the STN. The degree of attenuation was monotonic with increased DBS voltages in both locations, but this voltage-dependent effect was greater in the central STN than dorsal to the STN (p < 0.05. Cortical signals over the estimated origin of the hyperdirect pathway also demonstrated attenuation of beta hypersynchrony during DBS dorsal to or within STN, whereas signals from non-specific regions of motor cortex were not attenuated. The spatially specific suppression of beta synchrony in the motor cortex support the hypothesis that DBS may treat Parkinsonism by reducing excessive synchrony in the functionally connected sensorimotor network.

  13. A Miniature, Fiber-Coupled, Wireless, Deep-Brain Optogenetic Stimulator.

    Science.gov (United States)

    Lee, Steven T; Williams, Pete A; Braine, Catherine E; Lin, Da-Ting; John, Simon W M; Irazoqui, Pedro P

    2015-07-01

    Controlled, wireless neuromodulation using miniature implantable devices is a long-sought goal in neuroscience. It will allow many studies and treatments that are otherwise impractical. Recent studies demonstrate advances in neuromodulation through optogenetics, but test animals are typically tethered, severely limiting experimental possibilities. Existing nontethered optical stimulators either deliver light through a cranial window limiting applications to superficial layers of the brain, are not widely accessible due to highly specialized fabrication techniques, or do not demonstrate robust and flexible control of the optical power emitted. To overcome these limitations, we have developed a novel, miniature, wireless, deep-brain, modular optical stimulator with controllable stimulation parameters for use in optogenetic experiments. We demonstrate its use in a behavioral experiment targeting a deep brain structure in freely behaving mice. To allow its rapid and widespread adoption, we developed this stimulator using commercially available components. The modular and accessible optogenetic stimulator presented advances the wireless toolset available for freely behaving animal experiments.

  14. Combining non-invasive transcranial brain stimulation with neuroimaging and electrophysiology: Current approaches and future perspectives

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Karabanov, Anke; Hartwigsen, Gesa

    2016-01-01

    Non-invasive transcranial brain stimulation (NTBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial current stimulation (TCS) are important tools in human systems and cognitive neuroscience because they are able to reveal the relevance of certain brain structures...... are technically demanding. We argue that the benefit from this combination is twofold. Firstly, neuroimaging and electrophysiology can inform subsequent NTBS, providing the required information to optimize where, when, and how to stimulate the brain. Information can be achieved both before and during the NTBS...... experiment, requiring consecutive and concurrent applications, respectively. Secondly, neuroimaging and electrophysiology can provide the readout for neural changes induced by NTBS. Again, using either concurrent or consecutive applications, both "online" NTBS effects immediately following the stimulation...

  15. Deep brain stimulation effects in dystonia: time course of electrophysiological changes in early treatment.

    Science.gov (United States)

    Ruge, Diane; Tisch, Stephen; Hariz, Marwan I; Zrinzo, Ludvic; Bhatia, Kailash P; Quinn, Niall P; Jahanshahi, Marjan; Limousin, Patricia; Rothwell, John C

    2011-08-15

    Deep brain stimulation to the internal globus pallidus is an effective treatment for primary dystonia. The optimal clinical effect often occurs only weeks to months after starting stimulation. To better understand the underlying electrophysiological changes in this period, we assessed longitudinally 2 pathophysiological markers of dystonia in patients prior to and in the early treatment period (1, 3, 6 months) after deep brain stimulation surgery. Transcranial magnetic stimulation was used to track changes in short-latency intracortical inhibition, a measure of excitability of GABA(A) -ergic corticocortical connections and long-term potentiation-like synaptic plasticity (as a response to paired associative stimulation). Deep brain stimulation remained on for the duration of the study. Prior to surgery, inhibition was reduced and plasticity increased in patients compared with healthy controls. Following surgery and commencement of deep brain stimulation, short-latency intracortical inhibition increased toward normal levels over the following months with the same monotonic time course as the patients' clinical benefit. In contrast, synaptic plasticity changed rapidly, following a nonmonotonic time course: it was absent early (1 month) after surgery, and then over the following months increased toward levels observed in healthy individuals. We postulate that before surgery preexisting high levels of plasticity form strong memories of dystonic movement patterns. When deep brain stimulation is turned on, it disrupts abnormal basal ganglia signals, resulting in the absent response to paired associative stimulation at 1 month. Clinical benefit is delayed because engrams of abnormal movement persist and take time to normalize. Our observations suggest that plasticity may be a driver of long-term therapeutic effects of deep brain stimulation in dystonia.

  16. Me, Myself and My Brain Implant: Deep Brain Stimulation Raises Questions of Personal Authenticity and Alienation.

    Science.gov (United States)

    Kraemer, Felicitas

    2013-01-01

    In this article, I explore select case studies of Parkinson patients treated with deep brain stimulation (DBS) in light of the notions of alienation and authenticity. While the literature on DBS has so far neglected the issues of authenticity and alienation, I argue that interpreting these cases in terms of these concepts raises new issues for not only the philosophical discussion of neuro-ethics of DBS, but also for the psychological and medical approach to patients under DBS. In particular, I suggest that the experience of alienation and authenticity varies from patient to patient with DBS. For some, alienation can be brought about by neurointerventions because patients no longer feel like themselves. But, on the other hand, it seems alienation can also be cured by DBS as other patients experience their state of mind as authentic under treatment and retrospectively regard their former lives without stimulation as alienated. I argue that we must do further research on the relevance of authenticity and alienation to patients treated with DBS in order to gain a deeper philosophical understanding, and to develop the best evaluative criterion for the behavior of DBS patients.

  17. Cocaine enhances resistance to extinction of responding for brain-stimulation reward in adult prenatally stressed rats.

    Science.gov (United States)

    Gao, Shuibo; Suenaga, Toshiko; Oki, Yutaka; Yukie, Masao; Nakahara, Daiichiro

    2011-10-01

    The present experiment assessed whether prenatal stress (PS) can alter the ability of acute and chronic cocaine administration to increase and decrease the rewarding effectiveness of the medial forebrain bundle (MFB) using intracranial self-stimulation (ICSS), and also whether PS can affect the extinction of the MFB stimulation response. Adult male offspring of female rats that received PS or no PS (nPS) were implanted with MFB stimulating electrodes, and were then tested in ICSS paradigms. In both nPS and PS offspring, acute cocaine injection decreased ICSS thresholds dose-dependently. However, the threshold-lowering effects at any dose were not significantly different between groups. There was also no group-difference in the threshold-elevating effects of chronic cocaine administration. Nevertheless, chronically drug-administered PS rats exhibited a resistance to the extinguishing of the response for brain-stimulation reward when acutely treated with cocaine, as compared to extinction without cocaine treatment. The results suggest that PS may weaken the ability for response inhibition under cocaine loading in male adult offspring.

  18. A high-speed brain-computer interface (BCI) using dry EEG electrodes

    Science.gov (United States)

    Spüler, Martin

    2017-01-01

    Recently, brain-computer interfaces (BCIs) based on visual evoked potentials (VEPs) have been shown to achieve remarkable communication speeds. As they use electroencephalography (EEG) as non-invasive method for recording neural signals, the application of gel-based EEG is time-consuming and cumbersome. In order to achieve a more user-friendly system, this work explores the usability of dry EEG electrodes with a VEP-based BCI. While the results show a high variability between subjects, they also show that communication speeds of more than 100 bit/min are possible using dry EEG electrodes. To reduce performance variability and deal with the lower signal-to-noise ratio of the dry EEG electrodes, an averaging method and a dynamic stopping method were introduced to the BCI system. Those changes were shown to improve performance significantly, leading to an average classification accuracy of 76% with an average communication speed of 46 bit/min, which is equivalent to a writing speed of 8.8 error-free letters per minute. Although the BCI system works substantially better with gel-based EEG, dry EEG electrodes are more user-friendly and still allow high-speed BCI communication. PMID:28225794

  19. Improvement of both dystonia and tics with 60 Hz pallidal deep brain stimulation.

    Science.gov (United States)

    Hwynn, Nelson; Tagliati, Michele; Alterman, Ron L; Limotai, Natlada; Zeilman, Pamela; Malaty, Irene A; Foote, Kelly D; Morishita, Takashi; Okun, Michael S

    2012-09-01

    Deep brain stimulation has been utilized in both dystonia and in medication refractory Tourette syndrome. We present an interesting case of a patient with a mixture of disabling dystonia and Tourette syndrome whose coexistent dystonia and tics were successfully treated with 60 Hz-stimulation of the globus pallidus region.

  20. Enhancement of the amplitude of somatosensory evoked potentials following magnetic pulse stimulation of the human brain.

    Science.gov (United States)

    Seyal, M; Browne, J K; Masuoka, L K; Gabor, A J

    1993-01-01

    In this study we have demonstrated an enhancement of cortically generated wave forms of the somatosensory evoked potential (SEP) following magnetic pulse stimulation of the human brain. Subcortically generated activity was unaltered. The enhancement of SEP amplitude was greatest when the median nerve was stimulated 30-70 msec following magnetic pulse stimulation over the contralateral parietal scalp. We posit that the enhancement of the SEP is the result of synchronization of pyramidal cells in the sensorimotor cortex resulting from the magnetic pulse.

  1. Electrode alignment of transverse tripoles using a percutaneous triple-lead approach in spinal cord stimulation

    Science.gov (United States)

    Sankarasubramanian, V.; Buitenweg, J. R.; Holsheimer, J.; Veltink, P.

    2011-02-01

    The aim of this modeling study is to determine the influence of electrode alignment of transverse tripoles on the paresthesia coverage of the pain area in spinal cord stimulation, using a percutaneous triple-lead approach. Transverse tripoles, comprising a central cathode and two lateral anodes, were modeled on the low-thoracic vertebral region (T10-T12) using percutaneous triple-lead configurations, with the center lead on the spinal cord midline. The triple leads were oriented both aligned and staggered. In the staggered configuration, the anodes were offset either caudally (caudally staggered) or rostrally (rostrally staggered) with respect to the midline cathode. The transverse tripolar field steering with the aligned and staggered configurations enabled the estimation of dorsal column fiber thresholds (IDC) and dorsal root fiber thresholds (IDR) at various anodal current ratios. IDC and IDR were considerably higher for the aligned transverse tripoles as compared to the staggered transverse tripoles. The aligned transverse tripoles facilitated deeper penetration into the medial dorsal columns (DCs). The staggered transverse tripoles always enabled broad and bilateral DC activation, at the expense of mediolateral steerability. The largest DC recruited area was obtained with the rostrally staggered transverse tripole. Transverse tripolar geometries, using percutaneous leads, allow for selective targeting of either medial or lateral DC fibers, if and only if the transverse tripole is aligned. Steering of anodal currents between the lateral leads of the staggered transverse tripoles cannot target medially confined populations of DC fibers in the spinal cord. An aligned transverse tripolar configuration is strongly recommended, because of its ability to provide more post-operative flexibility than other configurations.

  2. Resilience in migraine brains: decrease of coherence after photic stimulation

    Science.gov (United States)

    Mendonça-de-Souza, Mayara; Monteiro, Ubirakitan M.; Bezerra, Amana S.; Silva-de-Oliveira, Ana P.; Ventura-da-Silva, Belvânia R.; Barbosa, Marcelo S.; de Souza, Josiane A.; Criado, Elisângela C.; Ferrarezi, Maria C. M.; Alencar, Giselly de A.; Lins, Otávio G.; Coriolano, Maria das G. W. S.; Costa, Belmira L. S. A.; Rodrigues, Marcelo C. A.

    2012-01-01

    Background: During migraine attacks, patients generally have photophobia and phonophobia and seek for environments with less sensorial stimulation. Present work aimed to quantify cortical partial directed coherence (PDC) of electroencephalographic (EEG) recordings from migraine patients and controls in occipital, parietal, and frontal areas with or without photic stimulation. Our hypothesis is that migraine patients with visual aura might have neuronal networks with higher coherence than controls even in interictal periods due to a predisposition in sensory cortical processing. Methods: Eleven adult women with migraine with visual aura (at least 48 h without previous attacks) and seven healthy adult woman were submitted to EEG recording in basal state and during photic stimulation. Results: When compared to healthy volunteers, migraine patients show different coherence profiles. Migraine patients had greater coherence than controls during the basal period (without photic stimulation), showing predisposition for sensory processing in many frequency ranges. After photic stimulation, patients showed a decrease in cortical coherence while controls had an increase. Conclusions: When compared to healty subjects, migraineurs show increased cortical coherence before photic stimulation, but a decrease when stimulation starts. This may be the expression of a resilience mechanism that allows migraineurs the interictal period. The PDC analysis permits to address a patient coherence profile, or “coherence map,” that can be utilized for management of the headache disorder or following up treatments. PMID:22837743

  3. RESILIENCE IN MIGRAINE BRAINS: DECREASE OF COHERENCE AFTER PHOTIC STIMULATION

    Directory of Open Access Journals (Sweden)

    Mayara eMendoca-de-Souza

    2012-07-01

    Full Text Available Background: During migraine attacks, patients generally have photophobia and phonophobia and seek for environments with less sensorial stimulation. Present work aimed to quantify cortical partial directed coherence (PDC of electroencephalographic (EEG recordings from migraine patients and controls in occipital, parietal and frontal areas with or without photic stimulation. Our hypothesis is that migraine patients with visual aura might have neuronal networks with higher coherence than controls even in interictal periods due to a predisposition in sensory cortical processing. Methods: Eleven adult women with migraine with visual aura (at least 48 hours without previous attacks and seven healthy adult woman were submitted to EEG recording in basal state and during photic stimulation. Results: When compared to healthy volunteers, migraine patients show different coherence profiles. Migraine patients had greater coherence than controls during the basal period (without photic stimulation, showing predisposition for sensory processing in many frequency ranges. After photic stimulation, patients showed a decrease in cortical coherence while controls had an increase. Conclusions: When compared to healty subjects, migraineurs show increased cortical coherence before photic stimulation, but a decrease when stimulation starts. This may be the expression of a resilience mechanism that allows migraineurs the interictal period. The PDC analysis permits to address a patient coherence profile, or coherence map, that can be utilized for management of the headache disorder or following up treatments.

  4. Brain stimulation and brain repair--rTMS: from animal experiment to clinical trials--what do we know?

    Science.gov (United States)

    Platz, Thomas; Rothwell, John C

    2010-01-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method of stimulating the brain that changes excitability at the site of stimulation as well as at distant anatomically connected sites. Since the effects can outlast the period of stimulation for minutes or hours and are thought to be depend, at least in part, on changes in the efficiency of synaptic connections in the cortex, the method has generated much interest as a potential therapeutic intervention in a wide range of neurological and psychiatric conditions. A symposium on brain stimulation and brain recovery was held in Greifswald (Germany) in 2010 to exchange of state-of-the-art knowledge about rTMS effects from animal experiments to clinical trials in conditions such as stroke, Parkinson disease, and depression. There was enormous interest in the effects of rTMS and signs of therapeutic success in mainly small clinical trials. However, it was also clear that some of our models of the effects of rTMS, such as upregulation or downregulation of specific brain areas may need further development if they are to account for all the observations that have been made so far. The results of the symposium are made available by lab reviews of members of the symposium's faculty. This editorial provides an overview.

  5. Emerging subspecialties in neurology: deep brain stimulation and electrical neuro-network modulation.

    Science.gov (United States)

    Hassan, Anhar; Okun, Michael S

    2013-01-29

    Deep brain stimulation (DBS) is a surgical therapy that involves the delivery of an electrical current to one or more brain targets. This technology has been rapidly expanding to address movement, neuropsychiatric, and other disorders. The evolution of DBS has created a niche for neurologists, both in the operating room and in the clinic. Since DBS is not always deep, not always brain, and not always simply stimulation, a more accurate term for this field may be electrical neuro-network modulation (ENM). Fellowships will likely in future years evolve their scope to include other technologies, and other nervous system regions beyond typical DBS therapy.

  6. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task

    Science.gov (United States)

    Laubacher, Marco; Aksöz, Efe A.; Binder-Macleod, Stuart; Hunt, Kenneth J.

    2016-01-01

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable. PMID:27478563

  7. Comparison of proximally versus distally placed spatially distributed sequential stimulation electrodes in a dynamic knee extension task

    Directory of Open Access Journals (Sweden)

    Marco Laubacher

    2016-06-01

    Full Text Available Spatially distributed sequential stimulation (SDSS has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES in the application of functional electrical stimulation (FES. This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14. Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s. The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively. With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively but of longer activation time (p=0.096. The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable.

  8. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves

    DEFF Research Database (Denmark)

    Rossini, P M; Burke, D; Chen, R

    2015-01-01

    in studying cognition, brain-behavior relationship and pathophysiology of various neurologic and psychiatric disorders. New paradigms of stimulation and new techniques have been developed. Furthermore, a large number of studies and clinical trials have demonstrated potential therapeutic applications of non......These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some...... of whom were in the panel of the 1994 "Report", was selected to produce a current state-of-the-art review of non-invasive stimulation both for clinical application and research in neuroscience. Since 1994, the international scientific community has seen a rapid increase in non-invasive brain stimulation...

  9. Deep brain stimulation reveals emotional impact processing in ventromedial prefrontal cortex

    DEFF Research Database (Denmark)

    Gjedde, Albert; Geday, Jacob

    2009-01-01

    We tested the hypothesis that modulation of monoaminergic tone with deep-brain stimulation (DBS) of subthalamic nucleus would reveal a site of reactivity in the ventromedial prefrontal cortex that we previously identified by modulating serotonergic and noradrenergic mechanisms by blocking serotonin......-noradrenaline reuptake sites. We tested the hypothesis in patients with Parkinson's disease in whom we had measured the changes of blood flow everywhere in the brain associated with the deep brain stimulation of the subthalamic nucleus. We determined the emotional reactivity of the patients as the average impact...... of emotive images rated by the patients off the DBS. We then searched for sites in the brain that had significant correlation of the changes of blood flow with the emotional impact rated by the patients. The results indicate a significant link between the emotional impact when patients are not stimulated...

  10. Brain responses to acupuncture stimulation in the prosthetic hand of an amputee patient.

    Science.gov (United States)

    Lee, In-Seon; Jung, Won-Mo; Lee, Ye-Seul; Wallraven, Christian; Chae, Younbyoung

    2015-10-01

    This report describes the brain responses to acupuncture in an upper limb amputee patient. A 62-year-old male had previously undergone a lower left arm amputation following an electrical accident. Using functional MRI, we investigated brain responses to acupuncture stimulation in the aforementioned amputee under three conditions: (a) intact hand, (b) prosthetic hand (used by the patient), and (c) fake fabric hand. The patient described greater de qi sensation when he received acupuncture stimulation in his prosthetic hand compared to a fake hand, with both stimulations performed in a similar manner. We found enhanced brain activation in the insula and sensorimotor cortex in response to acupuncture stimulation in the amputee's prosthetic hand, while there was only minimal activation in the visual cortex in response to acupuncture stimulation in a fake hand. The enhanced brain responses to acupuncture stimulation of the patient's prosthetic hand might be derived from cortical reorganisation, as he has been using his prosthetic hand for over 40 years. Our findings suggest the possible use of acupuncture stimulation in a prosthetic hand as an enhanced sensory feedback mechanism, which may represent a new treatment approach for phantom limb pain.

  11. Boosting brain excitability by transcranial high frequency stimulation in the ripple range.

    Science.gov (United States)

    Moliadze, Vera; Antal, Andrea; Paulus, Walter

    2010-12-15

    Alleviating the symptoms of neurological diseases by increasing cortical excitability through transcranial stimulation is an ongoing scientific challenge. Here, we tackle this issue by interfering with high frequency oscillations (80–250 Hz) via external application of transcranial alternating current stimulation (tACS) over the human motor cortex (M1). Twenty-one subjects participated in three different experimental studies and they received on separate days tACS at three frequencies (80 Hz, 140 Hz and 250 Hz) and sham stimulation in a randomized order. tACS with 140 Hz frequency increased M1 excitability as measured by transcranial magnetic stimulation-generated motor evoked potentials (MEPs) during and for up to 1 h after stimulation. Control experiments with sham and 80 Hz stimulation were without any effect, and 250 Hz stimulation was less efficient with a delayed excitability induction and reduced duration. After-effects elicited by 140 Hz stimulation were robust against inversion of test MEP amplitudes seen normally under activation. Stimulation at 140 Hz reduced short interval intracortical inhibition, but left intracortical facilitation, long interval cortical inhibition and cortical silent period unchanged. Implicit motor learning was not facilitated by 140 Hz stimulation. High frequency stimulation in the ripple range is a new promising non-invasive brain stimulation protocol to increase human cortical excitability during and after the end of stimulation.

  12. DARPP-32 expression in rat brain after electroconvulsive stimulation.

    Science.gov (United States)

    Rosa, Daniela V F; Souza, Renan P; Souza, Bruno R; Motta, Bernardo S; Caetano, Fernando; Jornada, Luciano K; Feier, Gustavo; Gomez, Marcus V; Quevedo, João; Romano-Silva, Marco A

    2007-11-07

    Although electroconvulsive therapy (ECT) has been used as a treatment for mental disorder since 1930s, little progress has been made in the mechanisms underlying its therapeutic or adverse effects. The aim of this work was to analyze the expression of DARPP-32 (a protein with a central role in dopaminergic signaling) in striatum, cortex, hippocampus and cerebellum of Wistar rats subjected to acute or chronic electroconvulsive stimulation (ECS). Rats were submitted to a single stimulation (acute) or to a series of eight stimulations, applied one every 48 h (chronic). Animals were killed for collection of tissue samples at time zero, 0.5, 3, 12, 24 and 48 h after stimulation in the acute model and at the same time intervals after the last stimulation in the chronic model. Our results indicated that acute ECS produces smaller changes in the expression of DARPP-32 but, interestingly, chronic ECS increased transient expression of DARPP-32 in several time frames, in striatum and hippocampus, after the last stimulation. Results on the expression of proteins involved in signaling pathways are relevant for neuropsychiatric disorders and treatment, in particular ECT, and can contribute to shed light on the mechanisms related to therapeutic and adverse effects.

  13. Deep Brain Stimulation Frequency—A Divining Rod for New and Novel Concepts of Nervous System Function and Therapy

    Directory of Open Access Journals (Sweden)

    Erwin B. Montgomery

    2016-08-01

    Full Text Available The efficacy of Deep Brain Stimulation (DBS for an expanding array of neurological and psychiatric disorders demonstrates directly that DBS affects the basic electroneurophysiological mechanisms of the brain. The increasing array of active electrode configurations, stimulation currents, pulse widths, frequencies, and pulse patterns provides valuable tools to probe electroneurophysiological mechanisms. The extension of basic electroneurophysiological and anatomical concepts using sophisticated computational modeling and simulation has provided relatively straightforward explanations of all the DBS parameters except frequency. This article summarizes current thought about frequency and relevant observations. Current methodological and conceptual errors are critically examined in the hope that future work will not replicate these errors. One possible alternative theory is presented to provide a contrast to many current theories. DBS, conceptually, is a noisy discrete oscillator interacting with the basal ganglia–thalamic–cortical system of multiple re-entrant, discrete oscillators. Implications for positive and negative resonance, stochastic resonance and coherence, noisy synchronization, and holographic memory (related to movement generation are presented. The time course of DBS neuronal responses demonstrates evolution of the DBS response consistent with the dynamics of re-entrant mechanisms. Finally, computational modeling demonstrates identical dynamics as seen by neuronal activities recorded from human and nonhuman primates, illustrating the differences of discrete from continuous harmonic oscillators and the power of conceptualizing the nervous system as composed on interacting discrete nonlinear oscillators.

  14. Deep Brain Stimulation Frequency-A Divining Rod for New and Novel Concepts of Nervous System Function and Therapy.

    Science.gov (United States)

    Montgomery, Erwin B; He, Huang

    2016-08-17

    The efficacy of Deep Brain Stimulation (DBS) for an expanding array of neurological and psychiatric disorders demonstrates directly that DBS affects the basic electroneurophysiological mechanisms of the brain. The increasing array of active electrode configurations, stimulation currents, pulse widths, frequencies, and pulse patterns provides valuable tools to probe electroneurophysiological mechanisms. The extension of basic electroneurophysiological and anatomical concepts using sophisticated computational modeling and simulation has provided relatively straightforward explanations of all the DBS parameters except frequency. This article summarizes current thought about frequency and relevant observations. Current methodological and conceptual errors are critically examined in the hope that future work will not replicate these errors. One possible alternative theory is presented to provide a contrast to many current theories. DBS, conceptually, is a noisy discrete oscillator interacting with the basal ganglia-thalamic-cortical system of multiple re-entrant, discrete oscillators. Implications for positive and negative resonance, stochastic resonance and coherence, noisy synchronization, and holographic memory (related to movement generation) are presented. The time course of DBS neuronal responses demonstrates evolution of the DBS response consistent with the dynamics of re-entrant mechanisms. Finally, computational modeling demonstrates identical dynamics as seen by neuronal activities recorded from human and nonhuman primates, illustrating the differences of discrete from continuous harmonic oscillators and the power of conceptualizing the nervous system as composed on interacting discrete nonlinear oscillators.

  15. Deep Brain Stimulation Frequency—A Divining Rod for New and Novel Concepts of Nervous System Function and Therapy

    Science.gov (United States)

    Montgomery, Erwin B.; He, Huang

    2016-01-01

    The efficacy of Deep Brain Stimulation (DBS) for an expanding array of neurological and psychiatric disorders demonstrates directly that DBS affects the basic electroneurophysiological mechanisms of the brain. The increasing array of active electrode configurations, stimulation currents, pulse widths, frequencies, and pulse patterns provides valuable tools to probe electroneurophysiological mechanisms. The extension of basic electroneurophysiological and anatomical concepts using sophisticated computational modeling and simulation has provided relatively straightforward explanations of all the DBS parameters except frequency. This article summarizes current thought about frequency and relevant observations. Current methodological and conceptual errors are critically examined in the hope that future work will not replicate these errors. One possible alternative theory is presented to provide a contrast to many current theories. DBS, conceptually, is a noisy discrete oscillator interacting with the basal ganglia–thalamic–cortical system of multiple re-entrant, discrete oscillators. Implications for positive and negative resonance, stochastic resonance and coherence, noisy synchronization, and holographic memory (related to movement generation) are presented. The time course of DBS neuronal responses demonstrates evolution of the DBS response consistent with the dynamics of re-entrant mechanisms. Finally, computational modeling demonstrates identical dynamics as seen by neuronal activities recorded from human and nonhuman primates, illustrating the differences of discrete from continuous harmonic oscillators and the power of conceptualizing the nervous system as composed on interacting discrete nonlinear oscillators. PMID:27548234

  16. Bimanual force coordination in Parkinson's disease patients with bilateral subthalamic deep brain stimulation.

    Directory of Open Access Journals (Sweden)

    Stacey L Gorniak

    Full Text Available OBJECTIVE: Studies of bimanual actions similar to activities of daily living (ADLs are currently lacking in evaluating fine motor control in Parkinson's disease patients implanted with bilateral subthalamic deep brain stimulators. We investigated basic time and force characteristics of a bimanual task that resembles performance of ADLs in a group of bilateral subthalamic deep brain stimulation (DBS patients. METHODS: Patients were evaluated in three different DBS parameter conditions off stimulation, on clinically derived stimulation parameters, and on settings derived from a patient-specific computational model. Model-based parameters were computed as a means to minimize spread of current to non-motor regions of the subthalamic nucleus via Cicerone Deep Brain Stimulation software. Patients were evaluated off parkinsonian medications in each stimulation condition. RESULTS: The data indicate that DBS parameter state does not affect most aspects of fine motor control in ADL-like tasks; however, features such as increased grip force and grip symmetry varied with the stimulation state. In the absence of DBS parameters, patients exhibited significant grip force asymmetry. Overall UPDRS-III and UPDRS-III scores associated with hand function were lower while patients were experiencing clinically-derived or model-based parameters, as compared to the off-stimulation condition. CONCLUSION: While bilateral subthalamic DBS has been shown to alleviate gross motor dysfunction, our results indicate that DBS may not provide the same magnitude of benefit to fine motor coordination.

  17. Modeling the effects of noninvasive transcranial brain stimulation at the biophysical, network, and cognitive Level

    DEFF Research Database (Denmark)

    Hartwigsen, Gesa; Bergmann, Til Ole; Herz, Damian Marc

    2015-01-01

    Noninvasive transcranial brain stimulation (NTBS) is widely used to elucidate the contribution of different brain regions to various cognitive functions. Here we present three modeling approaches that are informed by functional or structural brain mapping or behavior profiling and discuss how...... these approaches advance the scientific potential of NTBS as an interventional tool in cognitive neuroscience. (i) Leveraging the anatomical information provided by structural imaging, the electric field distribution in the brain can be modeled and simulated. Biophysical modeling approaches generate testable...... predictions regarding the impact of interindividual variations in cortical anatomy on the injected electric fields or the influence of the orientation of current flow on the physiological stimulation effects. (ii) Functional brain mapping of the spatiotemporal neural dynamics during cognitive tasks can...

  18. Noninvasive brain stimulation for Parkinson's disease and dystonia.

    Science.gov (United States)

    Wu, Allan D; Fregni, Felipe; Simon, David K; Deblieck, Choi; Pascual-Leone, Alvaro

    2008-04-01

    Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are promising noninvasive cortical stimulation methods for adjunctive treatment of movement disorders. They avoid surgical risks and provide theoretical advantages of specific neural circuit neuromodulation. Neuromodulatory effects depend on extrinsic stimulation factors (cortical target, frequency, intensity, duration, number of sessions), intrinsic patient factors (disease process, individual variability and symptoms, state of medication treatment), and outcome measures. Most studies to date have shown beneficial effects of rTMS or tDCS on clinical symptoms in Parkinson's disease (PD) and support the notion of spatial specificity to the effects on motor and nonmotor symptoms. Stimulation parameters have varied widely, however, and some studies are poorly controlled. Studies of rTMS or tDCS in dystonia have provided abundant data on physiology, but few on clinical effects. Multiple mechanisms likely contribute to the clinical effects of rTMS and tDCS in movement disorders, including normalization of cortical excitability, rebalancing of distributed neural network activity, and induction of dopamine release. It remains unclear how to individually adjust rTMS or tDCS factors for the most beneficial effects on symptoms of PD or dystonia. Nonetheless, the noninvasive nature, minimal side effects, positive effects in preliminary clinical studies, and increasing evidence for rational mechanisms make rTMS and tDCS attractive for ongoing investigation.

  19. Semi-automatic microdrive system for positioning electrodes during electrophysiological recordings from rat brain

    Science.gov (United States)

    Dabrowski, Piotr; Kublik, Ewa; Mozaryn, Jakub

    2015-09-01

    Electrophysiological recording of neuronal action potentials from behaving animals requires portable, precise and reliable devices for positioning of multiple microelectrodes in the brain. We propose a semi-automatic microdrive system for independent positioning of up to 8 electrodes (or tetrodes) in a rat (or larger animals). Device is intended to be used in chronic, long term recording applications in freely moving animals. Our design is based on independent stepper motors with lead screws which will offer single steps of ~ μm semi-automatically controlled from the computer. Microdrive system prototype for one electrode was developed and tested. Because of the lack of the systematic test procedures dedicated to such applications, we propose the evaluation of the prototype similar to ISO norm for industrial robots. To this end we designed and implemented magnetic linear and rotary encoders that provided information about electrode displacement and motor shaft movement. On the basis of these measurements we estimated repeatability, accuracy and backlash of the drive. According to the given assumptions and preliminary tests, the device should provide greater accuracy than hand-controlled manipulators available on the market. Automatic positioning will also shorten the course of the experiment and improve the acquisition of signals from multiple neuronal populations.

  20. Deep brain stimulation modulates synchrony within spatially and spectrally distinct resting state networks in Parkinson's disease.

    Science.gov (United States)

    Oswal, Ashwini; Beudel, Martijn; Zrinzo, Ludvic; Limousin, Patricia; Hariz, Marwan; Foltynie, Tom; Litvak, Vladimir; Brown, Peter

    2016-05-01

    Chronic dopamine depletion in Parkinson's disease leads to progressive motor and cognitive impairment, which is associated with the emergence of characteristic patterns of synchronous oscillatory activity within cortico-basal-ganglia circuits. Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson's disease, but its influence on synchronous activity in cortico-basal-ganglia loops remains to be fully characterized. Here, we demonstrate that deep brain stimulation selectively suppresses certain spatially and spectrally segregated resting state subthalamic nucleus-cortical networks. To this end we used a validated and novel approach for performing simultaneous recordings of the subthalamic nucleus and cortex using magnetoencephalography (during concurrent subthalamic nucleus deep brain stimulation). Our results highlight that clinically effective subthalamic nucleus deep brain stimulation suppresses synchrony locally within the subthalamic nucleus in the low beta oscillatory range and furthermore that the degree of this suppression correlates with clinical motor improvement. Moreover, deep brain stimulation relatively selectively suppressed synchronization of activity between the subthalamic nucleus and mesial premotor regions, including the supplementary motor areas. These mesial premotor regions were predominantly coupled to the subthalamic nucleus in the high beta frequency range, but the degree of deep brain stimulation-associated suppression in their coupling to the subthalamic nucleus was not found to correlate with motor improvement. Beta band coupling between the subthalamic nucleus and lateral motor areas was not influenced by deep brain stimulation. Motor cortical coupling with subthalamic nucleus predominantly involved driving of the subthalamic nucleus, with those drives in the higher beta frequency band having much shorter net delays to subthalamic nucleus than those in the lower beta band. These observations raise the

  1. Malignant neuroleptic syndrome following deep brain stimulation surgery: a case report

    Directory of Open Access Journals (Sweden)

    Stavrinou Lampis C

    2011-06-01

    Full Text Available Abstract Background The neuroleptic malignant syndrome is an uncommon but dangerous complication characterized by hyperthermia, autonomic dysfunction, altered mental state, hemodynamic dysregulation, elevated serum creatine kinase, and rigor. It is most often caused by an adverse reaction to anti-psychotic drugs or abrupt discontinuation of neuroleptic or anti-parkinsonian agents. To the best of our knowledge, it has never been reported following the common practice of discontinuation of anti-parkinsonian drugs during the pre-operative preparation for deep brain stimulation surgery for Parkinson's disease. Case presentation We present the first case of neuroleptic malignant syndrome associated with discontinuation of anti-parkinsonian medication prior to deep brain stimulation surgery in a 54-year-old Caucasian man. Conclusion The characteristic neuroleptic malignant syndrome symptoms can be attributed to other, more common causes associated with deep brain stimulation treatment for Parkinson's disease, thus requiring a high index of clinical suspicion to timely establish the correct diagnosis. As more centers become eligible to perform deep brain stimulation, neurologists and neurosurgeons alike should be aware of this potentially fatal complication. Timely activation of the deep brain stimulation system may be important in accelerating the patient's recovery.

  2. A history of deep brain stimulation: Technological innovation and the role of clinical assessment tools

    Science.gov (United States)

    2013-01-01

    Deep brain stimulation involves using a pacemaker-like device to deliver constant electrical stimulation to problematic areas within the brain. It has been used to treat over 40,000 people with Parkinson’s disease and essential tremor worldwide and is currently undergoing clinical trials as a treatment for depression and obsessive–compulsive disorder. This article will provide an historical account of deep brain stimulation in order to illustrate the plurality of interests involved in the development and stabilization of deep brain stimulation technology. Using Latour’s notion of immutable mobiles, this article will illustrate the importance of clinical assessment tools in shaping technological development in the era of medical device regulation. Given that such tools can serve commercial and professional interests, this article suggests that it is necessary to scrutinise their application in research contexts to ensure that they capture clinical changes that are meaningful for patients and their families. This is particularly important in relation to potentially ethically problematic therapies such as deep brain stimulation for psychiatric disorders.

  3. Friends, not foes: Magnetoencephalography as a tool to uncover brain dynamics during transcranial alternating current stimulation.

    Science.gov (United States)

    Neuling, Toralf; Ruhnau, Philipp; Fuscà, Marco; Demarchi, Gianpaolo; Herrmann, Christoph S; Weisz, Nathan

    2015-09-01

    Brain oscillations are supposedly crucial for normal cognitive functioning and alterations are associated with cognitive dysfunctions. To demonstrate their causal role on behavior, entrainment approaches in particular aim at driving endogenous oscillations via rhythmic stimulation. Within this context, transcranial electrical stimulation, especially transcranial alternating current stimulation (tACS), has received renewed attention. This is likely due to the possibility of defining oscillatory stimulation properties precisely. Also, measurements comparing pre-tACS with post-tACS electroencephalography (EEG) have shown impressive modulations. However, the period during tACS has remained a blackbox until now, due to the enormous stimulation artifact. By means of application of beamforming to magnetoencephalography (MEG) data, we successfully recovered modulations of the amplitude of brain oscillations during weak and strong tACS. Additionally, we demonstrate that also evoked responses to visual and auditory stimuli can be recovered during tACS. The main contribution of the present study is to provide critical evidence that during ongoing tACS, subtle modulations of oscillatory brain activity can be reconstructed even at the stimulation frequency. Future tACS experiments will be able to deliver direct physiological insights in order to further the understanding of the contribution of brain oscillations to cognition and behavior.

  4. Prolonged repeated acupuncture stimulation induces habituation effects in pain-related brain areas: an FMRI study.

    Directory of Open Access Journals (Sweden)

    Chuanfu Li

    Full Text Available Most previous studies of brain responses to acupuncture were designed to investigate the acupuncture instant effect while the cumulative effect that should be more important in clinical practice has seldom been discussed. In this study, the neural basis of the acupuncture cumulative effect was analyzed. For this experiment, forty healthy volunteers were recruited, in which more than 40 minutes of repeated acupuncture stimulation was implemented at acupoint Zhusanli (ST36. Three runs of acupuncture fMRI datasets were acquired, with each run consisting of two blocks of acupuncture stimulation. Besides general linear model (GLM analysis, the cumulative effects of acupuncture were analyzed with analysis of covariance (ANCOVA to find the association between the brain response and the cumulative duration of acupuncture stimulation in each stimulation block. The experimental results showed that the brain response in the initial stage was the strongest although the brain response to acupuncture was time-variant. In particular, the brain areas that were activated in the first block and the brain areas that demonstrated cumulative effects in the course of repeated acupuncture stimulation overlapped in the pain-related areas, including the bilateral middle cingulate cortex, the bilateral paracentral lobule, the SII, and the right thalamus. Furthermore, the cumulative effects demonstrated bimodal characteristics, i.e. the brain response was positive at the beginning, and became negative at the end. It was suggested that the cumulative effect of repeated acupuncture stimulation was consistent with the characteristic of habituation effects. This finding may explain the neurophysiologic mechanism underlying acupuncture analgesia.

  5. Deep brain stimulation of the antero-medial globus pallidus interna for Tourette syndrome.

    Directory of Open Access Journals (Sweden)

    Perminder S Sachdev

    Full Text Available BACKGROUND: We have previously reported the results of Deep Brain Stimulation (DBS of the antero-medial globus pallidus interna (GPi for severe Tourette Syndrome (TS in 11 patients. We extend this case series to 17 patients and a longer follow-up to a maximum of 46 months. METHODS: 17 patients (14 male; mean age 29.1 years, range 17-51 years with severe and medically intractable TS were implanted with Medtronic quadripolar electrodes bilaterally in the antero-medial GPi. The primary outcome measure was the Yale Global Tic Severity Scale (YGTSS. Secondary outcome measures included the Yale-Brown Obsessive Compulsive Scale, Hamilton Depression Rating Scale, Gilles de la Tourette Quality of Life Scale and Global Assessment of Functioning. Follow up was at one month, three months and finally at a mean 24.1 months (range 8-46 months following surgery. RESULTS: Overall, there was a 48.3% reduction in motor tics and a 41.3% reduction in phonic tics at one month, and this improvement was maintained at final follow-up. 12 out of 17 (70.6% patients had a>50% reduction in YGTSS score at final follow up. Only 8 patients required ongoing pharmacotherapy for tics post-surgery. Patients improved significantly on all secondary measures. Adverse consequences included lead breakage in 4 patients, infection (1, transient anxiety (2, dizziness (1, poor balance (1 and worsening of stuttering (1. CONCLUSIONS: This case series provides further support that antero-medial GPi DBS is an effective and well tolerated treatment for a subgroup of severe TS, with benefits sustained up to 4 years.

  6. The phenomenology of deep brain stimulation-induced changes in OCD: an enactive affordance-based model.

    Science.gov (United States)

    de Haan, Sanneke; Rietveld, Erik; Stokhof, Martin; Denys, Damiaan

    2013-01-01

    People suffering from Obsessive-Compulsive Disorder (OCD) do things they do not want to do, and/or they think things they do not want to think. In about 10% of OCD patients, none of the available treatment options is effective. A small group of these patients is currently being treated with deep brain stimulation (DBS). DBS involves the implantation of electrodes in the brain. These electrodes give a continuous electrical pulse to the brain area in which they are implanted. It turns out that patients may experience profound changes as a result of DBS treatment. It is not just the symptoms that change; patients rather seem to experience a different way of being in the world. These global effects are insufficiently captured by traditional psychiatric scales, which mainly consist of behavioral measures of the severity of the symptoms. In this article we aim to capture the changes in the patients' phenomenology and make sense of the broad range of changes they report. For that we introduce an enactive, affordance-based model that fleshes out the dynamic interactions between person and world in four aspects. The first aspect is the patients' experience of the world. We propose to specify the patients' world in terms of a field of affordances, with the three dimensions of broadness of scope ("width" of the field), temporal horizon ("depth"), and relevance of the perceived affordances ("height"). The second aspect is the person-side of the interaction, that is, the patients' self-experience, notably their moods and feelings. Thirdly, we point to the different characteristics of the way in which patients relate to the world. And lastly, the existential stance refers to the stance that patients take toward the changes they experience: the second-order evaluative relation to their interactions and themselves. With our model we intend to specify the notion of being in the world in order to do justice to the phenomenological effects of DBS treatment.

  7. Effects of non-invasive brain stimulation on associative memory.

    Science.gov (United States)

    Matzen, Laura E; Trumbo, Michael C; Leach, Ryan C; Leshikar, Eric D

    2015-10-22

    Associative memory refers to remembering the association between two items, such as a face and a name. It is a crucial part of daily life, but it is also one of the first aspects of memory performance that is impacted by aging and by Alzheimer's disease. Evidence suggests that transcranial direct current stimulation (tDCS) can improve memory performance, but few tDCS studies have investigated its impact on associative memory. In addition, no prior study of the effects of tDCS on memory performance has systematically evaluated the impact of tDCS on different types of memory assessments, such as recognition and recall tests. In this study, we measured the effects of tDCS on associative memory performance in healthy adults, using both recognition and recall tests. Participants studied face-name pairs while receiving either active (30 min, 2 mA) or sham (30 min, 0.1 mA) stimulation with the anode placed at F9 and the cathode placed on the contralateral upper arm. Participants in the active stimulation group performed significantly better on the recall test than participants in the sham group, recalling 50% more names, on average, and making fewer recall errors. However, the two groups did not differ significantly in terms of their performance on the recognition memory test. This investigation provides evidence that stimulation at the time of study improves associative memory encoding, but that this memory benefit is evident only under certain retrieval conditions.

  8. Deep brain stimulation of the globus pallidus internus (GPI) for torsion dystonia--a report of two cases.

    Science.gov (United States)

    Vesper, J; Klostermann, F; Funk, Th; Stockhammer, F; Brock, M

    2002-01-01

    Generalized dystonia is known as a type of movement disorder in which pharmacotherapeutic options are very limited. Deep Brain Stimulation (DBS) is well established for Parkinson's disease (PD) and tremor dominant movement disorders. We report on two cases of generalized dystonia which were successfully treated by chronic high frequency stimulation in the Globus pallidus internus (GPI). Two 26 and 27 years old males suffered from severe torsion dystonia and multisegmental dystonia of the lower limbs. Case 1 is a familiar type of dystonia (DYT1 positive). The onset of symptoms in both cases was at age 7. The complaints were initially treated with orally administered benzodiazepines, anticholinergic drugs, later by baclofen and L-DOPA. However there was no response. Case 2 was a patient with a history of left side dominated dystonia since the age of 8. It was first diagnosed as a psychogenic movement disorder. Prior to surgery he was treated with L-DOPA, anticholinergics, Baclofen without any effect. There was only a limited effect on high doses of diazepam. The patient is DYT1 negative. The target point was on both sides the GPI. Intraoperative computerized tomography (CT) and ventriculography (VG) were used for target setting. Furthermore microrecordings were helpful to ensure the exact electrode position. Surgery was performed under analgosedation. Two weeks after surgery we first observed a relief of symptoms in both cases. A significant reduction in the Burke-Fahn-Marsden-Dystonia Movement Rating Scale was observed at the 6 month follow-up (case 1: 95%, case 2: 80%). In case 1 a slight dystonic movement of the left ankle was the only remaining symptom under stimulation. The medication was continuously reduced. At the 24 month follow-up the effect of stimulation remained unchanged. However high stimulation parameters are required to maintain an optimal effect (mean 3.5 V, 400 microseconds, 145 Hz).

  9. A novel bioelectronic nose based on brain-machine interface using implanted electrode recording in vivo in olfactory bulb.

    Science.gov (United States)

    Dong, Qi; Du, Liping; Zhuang, Liujing; Li, Rong; Liu, Qingjun; Wang, Ping

    2013-11-15

    The mammalian olfactory system has merits of higher sensitivity, selectivity and faster response than current electronic nose system based on chemical sensor array. It is advanced and feasible to detect and discriminate odors by mammalian olfactory system. The purpose of this study is to develop a novel bioelectronic nose based on the brain-machine interface (BMI) technology for odor detection by in vivo electrophysiological measurements of olfactory bulb. In this work, extracellular potentials of mitral/tufted (M/T) cells in olfactory bulb (OB) were recorded by implanted 16-channel microwire electrode arrays. The odor-evoked response signals were analyzed. We found that neural activities of different neurons showed visible different firing patterns both in temporal features and rate features when stimulated by different small molecular odorants. The detection low limit is below 1 ppm for some specific odors. Odors were classified by an algorithm based on population vector similarity and support vector machine (SVM). The results suggested that the novel bioelectonic nose was sensitive to odorant stimuli. The best classifying accuracy was up to 95%. With the development of the BMI and olfactory decoding methods, we believe that this system will represent emerging and promising platforms for wide applications in medical diagnosis and security fields.

  10. Human brain activation during sexual stimulation of the penis

    NARCIS (Netherlands)

    Georgiadis, [No Value; Holstege, G; Georgiadis, Janniko R.

    2005-01-01

    Penile sensory information is essential for reproduction, but almost nothing is known about how sexually salient inputs from the penis are processed in the brain. We used positron emission tomography to measure regional cerebral blood flow (rCBF) during various stages of male sexual performance. Com

  11. Reducing proactive aggression through non-invasive brain stimulation

    NARCIS (Netherlands)

    Dambacher, F.; Schuhmann, T.; Lobbestael, J.; Arntz, A.; Brugman, S.; Sack, A.T.

    2015-01-01

    Aggressive behavior poses a threat to human collaboration and social safety. It is of utmost importance to identify the functional mechanisms underlying aggression and to develop potential interventions capable of reducing dysfunctional aggressive behavior already at a brain level. We here experimen

  12. Modulation of Brain Dead Induced Inflammation by Vagus Nerve Stimulation

    NARCIS (Netherlands)

    Hoeger, S.; Bergstraesser, C.; Selhorst, J.; Fontana, J.; Birck, R.; Waldherr, R.; Beck, G.; Sticht, C.; Seelen, M. A.; van Son, W. J.; Leuvenink, H.; Ploeg, R.; Schnuelle, P.; Yard, B. A.

    2010-01-01

    Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (

  13. Stability and selectivity of a chronic, multi-contact cuff electrode for sensory stimulation in human amputees

    Science.gov (United States)

    Tan, Daniel W.; Schiefer, Matthew A.; Keith, Michael W.; Anderson, J. Robert; Tyler, Dustin J.

    2015-04-01

    Objective. Stability and selectivity are important when restoring long-term, functional sensory feedback in individuals with limb-loss. Our objective is to demonstrate a chronic, clinical neural stimulation system for providing selective sensory response in two upper-limb amputees. Approach. Multi-contact cuff electrodes were implanted in the median, ulnar, and radial nerves of the upper-limb. Main results. Nerve stimulation produced a selective sensory response on 19 of 20 contacts and 16 of 16 contacts in subjects 1 and 2, respectively. Stimulation elicited multiple, distinct percept areas on the phantom and residual limb. Consistent threshold, impedance, and percept areas have demonstrated that the neural interface is stable for the duration of this on-going, chronic study. Significance. We have achieved selective nerve response from multi-contact cuff electrodes by demonstrating characteristic percept areas and thresholds for each contact. Selective sensory response remains consistent in two upper-limb amputees for 1 and 2 years, the longest multi-contact sensory feedback system to date. Our approach demonstrates selectivity and stability can be achieved through an extraneural interface, which can provide sensory feedback to amputees.

  14. A Power-Efficient Wireless System With Adaptive Supply Control for Deep Brain Stimulation

    Science.gov (United States)

    Lee, Hyung-Min; Park, Hangue; Ghovanloo, Maysam

    2014-01-01

    A power-efficient wireless stimulating system for a head-mounted deep brain stimulator (DBS) is presented. A new adaptive rectifier generates a variable DC supply voltage from a constant AC power carrier utilizing phase control feedback, while achieving high AC-DC power conversion efficiency (PCE) through active synchronous switching. A current-controlled stimulator adopts closed-loop supply control to automatically adjust the stimulation compliance voltage by detecting stimulation site potentials through a voltage readout channel, and improve the stimulation efficiency. The stimulator also utilizes closed-loop active charge balancing to maintain the residual charge at each site within a safe limit, while receiving the stimulation parameters wirelessly from the amplitude-shift-keyed power carrier. A 4-ch wireless stimulating system prototype was fabricated in a 0.5-μm 3M2P standard CMOS process, occupying 2.25 mm². With 5 V peak AC input at 2 MHz, the adaptive rectifier provides an adjustable DC output between 2.5 V and 4.6 V at 2.8 mA loading, resulting in measured PCE of 72 ~ 87%. The adaptive supply control increases the stimulation efficiency up to 30% higher than a fixed supply voltage to 58 ~ 68%. The prototype wireless stimulating system was verified in vitro. PMID:24678126

  15. Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning.

    Science.gov (United States)

    Katnani, Husam A; Patel, Shaun R; Kwon, Churl-Su; Abdel-Aziz, Samer; Gale, John T; Eskandar, Emad N

    2016-01-04

    The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect.

  16. Understanding the behavioural consequences of noninvasive brain stimulation.

    Science.gov (United States)

    Bestmann, Sven; de Berker, Archy O; Bonaiuto, James

    2015-01-01

    Transcranial electrical stimulation (tES) influences neural activity in a way that can elicit behavioural change but may also improve high-level cognition or ameliorate symptoms in neuropsychiatric disorders. However, the current fervour for tES contrasts with the paucity of mechanistically detailed models of how stimulation causes behavioural change. Here we challenge the plausibility of several common assumptions and interpretations of tES and discuss how to bridge the ravines separating our understanding of the behavioural and neural consequences of tES. We argue that rational application of tES should occur in tandem with computational neurostimulation and appropriate physiological and behavioural assays. This will aid appreciation of the limitations of tES and generate testable predictions of how tES expresses its effects on behaviour.

  17. Kappa opioid receptors stimulate phosphoinositide turnover in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Periyasamy, S.; Hoss, W. (Univ. of Toledo, OH (USA))

    1990-01-01

    The effects of various subtype-selective opioid agonists and antagonists on the phosphoinositide (PI) turnover response were investigated in the rat brain. The {kappa}-agonists U-50,488H and ketocyclazocine produced a concentration-dependent increase in the accumulation of IP's in hippocampal slices. The other {kappa}-agonists Dynorphin-A (1-13) amide, and its protected analog D(Ala){sup 2}-dynorphin-A (1-13) amide also produced a significant increase in the formation of ({sup 3}H)-IP's, whereas the {mu}-selective agonists (D-Ala{sup 2}-N-Me-Phe{sup 4}-Gly{sup 5}-ol)-enkephalin and morphine and the {delta}-selective agonist (D-Pen{sup 2,5})-enkephalin were ineffective. The increase in IP's formation elicited by U-50,488H was partially antagonized by naloxone and more completely antagonized by the {kappa}-selective antagonists nor-binaltorphimine and MR 2266. The formation of IP's induced by U-50,488H varies with the regions of the brain used, being highest in hippocampus and amygdala, and lowest in striatum and pons-medullar. The results indicate that brain {kappa}- but neither {mu}- nor {delta}- receptors are coupled to the PI turnover response.

  18. [Abscess at the implant site following apical parodontitis. Hardware-related complications of deep brain stimulation].

    Science.gov (United States)

    Sixel-Döring, F; Trenkwalder, C; Kappus, C; Hellwig, D

    2006-08-01

    Deep brain stimulation of the subthalamic nucleus is an important treatment option for advanced stages of idiopathic Parkinson's disease, leading to significant improvement of motor symptoms in suited patients. Hardware-related complications such as technical malfunction, skin erosion, and infections however cause patient discomfort and additional expense. The patient presented here suffered a putrid infection of the impulse generator site following only local dental treatment of apical parodontitis. Therefore, prophylactic systemic antibiotic treatment is recommended for patients with implanted deep brain stimulation devices in case of operations, dental procedures, or infectious disease.

  19. Current perspectives on deep brain stimulation for severe neurological and psychiatric disorders

    Directory of Open Access Journals (Sweden)

    Kocabicak E

    2015-04-01

    Full Text Available Ersoy Kocabicak,1–3 Yasin Temel,1,2 Anke Höllig,4 Björn Falkenburger,5 Sonny KH Tan2,4 1Department of Neurosurgery, Maastricht University Medical Centre, 2Department of Neuroscience, Maastricht University, Maastricht, the Netherlands; 3Department of Neurosurgery, Ondokuz Mayis University, Samsun, Turkey; 4Department of Neurosurgery, 5Department of Neurology, RWTH Aachen University, Aachen, Germany Abstract: Deep brain stimulation (DBS has become a well-accepted therapy to treat movement disorders, including Parkinson’s disease, essential tremor, and dystonia. Long-term follow-up studies have demonstrated sustained improvement in motor symptoms and quality of life. DBS offers the opportunity to selectively modulate the targeted brain regions and related networks. Moreover, stimulation can be adjusted according to individual patients’ demands, and stimulation is reversible. This has led to the introduction of DBS as a treatment for further neurological and psychiatric disorders and many clinical studies investigating the efficacy of stimulating various brain regions in order to alleviate severe neurological or psychiatric disorders including epilepsy, major depression, and obsessive–compulsive disorder. In this review, we provide an overview of accepted and experimental indications for DBS therapy and the corresponding anatomical targets. Keywords: deep brain stimulation, movement disorders, neurological disorders, psychiatric disorders, Parkinson’s disease

  20. Noninvasive brain stimulation in neurorehabilitation: Local and distant effects for motor recovery

    Directory of Open Access Journals (Sweden)

    Sook-Lei eLiew

    2014-06-01

    Full Text Available Noninvasive brain stimulation (NIBS may enhance motor recovery after neurological injury through the causal induction of plasticity processes. Neurological injury, such as stroke, often results in serious long-term physical disabilities, and despite intensive therapy, a large majority of brain injury survivors fail to regain full motor function. Emerging research suggests that NIBS techniques, such as transcranial magnetic (TMS and direct current (tDCS stimulation, in association with customarily used neurorehabilitative treatments, may enhance motor recovery. This paper provides a general review on TMS and tDCS paradigms, the mechanisms by which they operate and the stimulation techniques used in neurorehabilitation, specifically stroke. TMS and tDCS influence regional neural activity underlying the stimulation location and also distant interconnected network activity throughout the brain. We discuss recent studies that document NIBS effects on global brain activity measured with various neuroimaging techniques, which help to characterize better strategies for more accurate NIBS stimulation. These rapidly growing areas of inquiry may hold potential for improving the effectiveness of NIBS-based interventions for clinical rehabilitation.

  1. Non-invasive brain stimulation in neurorehabilitation: local and distant effects for motor recovery.

    Science.gov (United States)

    Liew, Sook-Lei; Santarnecchi, Emilliano; Buch, Ethan R; Cohen, Leonardo G

    2014-01-01

    Non-invasive brain stimulation (NIBS) may enhance motor recovery after neurological injury through the causal induction of plasticity processes. Neurological injury, such as stroke, often results in serious long-term physical disabilities, and despite intensive therapy, a large majority of brain injury survivors fail to regain full motor function. Emerging research suggests that NIBS techniques, such as transcranial magnetic (TMS) and direct current (tDCS) stimulation, in association with customarily used neurorehabilitative treatments, may enhance motor recovery. This paper provides a general review on TMS and tDCS paradigms, the mechanisms by which they operate and the stimulation techniques used in neurorehabilitation, specifically stroke. TMS and tDCS influence regional neural activity underlying the stimulation location and also distant interconnected network activity throughout the brain. We discuss recent studies that document NIBS effects on global brain activity measured with various neuroimaging techniques, which help to characterize better strategies for more accurate NIBS stimulation. These rapidly growing areas of inquiry may hold potential for improving the effectiveness of NIBS-based interventions for clinical rehabilitation.

  2. Vagal stimulation modulates inflammation through a ghrelin mediated mechanism in traumatic brain injury

    OpenAIRE

    Bansal, V; Ryu, SY; Lopez, N; Allexan, S; Krzyzaniak, M; Eliceiri, B; Baird, A.; Coimbra, R

    2012-01-01

    Traumatic brain injury (TBI) releases a cascade of inflammatory cytokines. Vagal nerve stimulation (VNS) and ghrelin have known anti-inflammatory effects; furthermore, ghrelin release is stimulated by acetylcholine. We hypothesized VNS decreases post-TBI inflammation through a ghrelin-mediated mechanism. TBI was created in five groups of mice: sham, TBI, TBI/ghrelin, TBI/VNS, and TBI/VNS/ghrelin receptor antagonist (GRa). Serum and tissue ghrelin, and serum TNF-αwere measured. Ghrelin increas...

  3. Brain mapping with transcranial magnetic stimulation using a refined correlation ratio and Kendall's tau.

    Science.gov (United States)

    Matthäus, L; Trillenberg, P; Fadini, T; Finke, M; Schweikard, A

    2008-11-10

    Transcranial magnetic stimulation provides a mean to stimulate the brain non-invasively and painlessly. The effect of the stimulation hereby depends on the stimulation coil used and on its placement. This paper presents a mapping algorithm based on the assumption of a monotonous functional relationship between the applied electric field strength at the representation point of a muscle and the evoked motor potential. We combine data from coil characteristics, coil placement, and stimulation outcome to calculate a likelihood map for the representation of stimulated muscles in the brain. Hereby, correlation ratio (CR) and Kendall's rank coefficient tau are used to find areas in the brain where there is most likely a functional or monotonous relationship between electric field strength applied to this area and the muscle response. First results show a good accordance of our method with mapping from functional magnetic resonance imaging. In our case, classical evaluation of CR with binning is impossible, because sample data sets are too small and data are continuous. We therefore introduce a refined CR formula based on a Parzen windowing of the X-data to solve the problem. In contrast to usual windowing approaches, which require numeric integration, it can be evaluated directly in O(n2) time. Hence, its advantage lies in fast evaluation while maintaining robust applicability to small sample sets. We suggest that the presented formula can generally be used in CR-related problems where sample size is small and data range is continuous.

  4. [Repetitive Transcranial Magnetic Stimulation (rTMS) for Higher Brain Function Deficits].

    Science.gov (United States)

    Inoue, Yukichi

    2016-12-01

    The management of higher brain dysfunctions such as stroke-induced unilateral spatial neglect (USN) or aphasia is crucial because these dysfunctions have devastating neurological repercussions on the patients' daily life and quality of life. Impairment of the physiological interhemispheric rivalry is often the result of brain insults such as strokes or traumatic injuries, and it may lead to USN or aphasia. Repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation method, is a promising tool for restoring the pathological imbalance in interhemispheric rivalry by either suppressing the hyperactivity of the unaffected hemisphere or facilitating hypoactivity in the affected hemisphere. The concept of paradoxical functional facilitation (Kapur, 1996) has important clinical implications when coupled with rTMS applications. In addition to conventional rTMS (c-rTMS), other clinically relevant protocols of patterned rTMS (p-rTMS) have been developed: the theta burst stimulation (TBS), the paired associative stimulation (PAS), and the quadripulse stimulation (QPS). TBS is commonly used in the rehabilitation of patients with post-stroke USN and those with non-fluent aphasia because of its prolonged beneficial effects and the short duration of stimulation. TBS may be considered an effective and safe protocol of rTMS. We foresee broader clinical applications of p-rTMS (TBS) and c-rTMS in the treatment of various neurological deficits.

  5. Measuring Brain Stimulation Induced Changes in Cortical Properties Using TMS-EEG.

    Science.gov (United States)

    Chung, Sung Wook; Rogasch, Nigel C; Hoy, Kate E; Fitzgerald, Paul B

    2015-01-01

    Neuromodulatory brain stimulation can induce plastic reorganization of cortical circuits that persist beyond the period of stimulation. Most of our current knowledge about the physiological properties has been derived from the motor cortex. The integration of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) is a valuable method for directly probing excitability, connectivity and oscillatory dynamics of regions throughout the brain. Offering in depth measurement of cortical reactivity, TMS-EEG allows the evaluation of TMS-evoked components that may act as a marker for cortical excitation and inhibition. A growing body of research is using concurrent TMS and EEG (TMS-EEG) to explore the effects of different neuromodulatory techniques such as repetitive TMS and transcranial direct current stimulation on cortical function, particularly in non-motor regions. In this review, we outline studies examining TMS-evoked potentials and oscillations before and after, or during a single session of brain stimulation. Investigating these studies will aid in our understanding of mechanisms involved in the modulation of excitability and inhibition by neuroplasticity following different stimulation paradigms.

  6. Targeting Neuronal Networks with Combined Drug and Stimulation Paradigms Guided by Neuroimaging to Treat Brain Disorders.

    Science.gov (United States)

    Faingold, Carl L; Blumenfeld, Hal

    2015-10-01

    Improved therapy of brain disorders can be achieved by focusing on neuronal networks, utilizing combined pharmacological and stimulation paradigms guided by neuroimaging. Neuronal networks that mediate normal brain functions, such as hearing, interact with other networks, which is important but commonly neglected. Network interaction changes often underlie brain disorders, including epilepsy. "Conditional multireceptive" (CMR) brain areas (e.g., brainstem reticular formation and amygdala) are critical in mediating neuroplastic changes that facilitate network interactions. CMR neurons receive multiple inputs but exhibit extensive response variability due to milieu and behavioral state changes and are exquisitely sensitive to agents that increase or inhibit GABA-mediated inhibition. Enhanced CMR neuronal responsiveness leads to expression of emergent properties--nonlinear events--resulting from network self-organization. Determining brain disorder mechanisms requires animals that model behaviors and neuroanatomical substrates of human disorders identified by neuroimaging. However, not all sites activated during network operation are requisite for that operation. Other active sites are ancillary, because their blockade does not alter network function. Requisite network sites exhibit emergent properties that are critical targets for pharmacological and stimulation therapies. Improved treatment of brain disorders should involve combined pharmacological and stimulation therapies, guided by neuroimaging, to correct network malfunctions by targeting specific network neurons.

  7. Chaotic electrical stimulation of the subthalamic nucleus - mossy fiber sprouting, epileptic seizures, and brain electrical activity in pentylenetetrazol-kindled rats

    Institute of Scientific and Technical Information of China (English)

    Shenggen Chen; Chunhui Che; Huapin Huang; Changyun Liu; Xiaoyun Zhuang; Fang Jiang

    2008-01-01

    BACKGROUND: Previous studies have demonstrated that appropriate interventions can alter brain electrical activity of epileptic patients prior to and during a seizure, leading to maintenance of a highly chaotic state, thereby inhibiting abnormal epileptic discharges, and eventually controlling epileptic seizure. OBJECTIVE: This study was designed to observe the effects of chaotic electrical stimulation to the subthalamic nucleus on mossy fiber sprouting, epileptic seizures, and electrical discharges, and to summarize the most suitable intervention. DESIGN, TIME AND SETTING: This randomized grouping, neuroelectrophysiological study was performed at the Laboratory of Neurology, Union Hospital Affiliated to Fujian Medical University in September 2007.MATERIALS: Fifty-five healthy, male, Sprague Dawley rats were subjected to an epileptic model by an intraperitoneal injection of pentylenetetrazol. The YC-2 programmed electrical stimulator was provided by Chengdu Instrument Factory, China; the video electroencephalographic system (KT-88-2400) and 24-hour active electroencephalographic system were products of Contec Medical System Co., Ltd., China; pentylenetetrazol was purchased from Sigma, USA.METHODS: The present interventional method consisted of electrical stimulation to the subthalamic nucleus with an intensity of 500 μ A, pulse width 0.05 ms, frequency 30 Hz, and a duration of 20 minutes for 14 successive days. Fifty-five rats were divided into 6 groups: (1) pre-stimulation (n = 10), pentylenetetrazol was administered and 30 minutes later, chaotic electrical stimulation was performed; (2) synchronous stimulation (n = 10), rats received pentylenetetrazol and chaotic electrical stimulation concurrently; (3) post-administration stimulation (n = 10), after pentylenetetrazol administration, chaotic electrical stimulation was performed immediately after cessation of a seizure; (4) sham-stimulation (n = 10), following pentylenetetrazol administration, an electrode was

  8. Extracellular stimulation window explained by a geometry-based model of the neuron-electrode contact

    NARCIS (Netherlands)

    Buitenweg, Jan Reinoud; Rutten, Wim L.C.; Marani, Enrico

    2002-01-01

    Extracellular stimulation of single cultured neurons which are completely sealing a microelectrode is usually performed using anodic or biphasic currents of at least 200 nA. However, recently obtained experimental data demonstrate the possibility to stimulate a neuron using cathodic current pulses w

  9. Application of non-linear control theory to a model of deep brain stimulation.

    Science.gov (United States)

    Davidson, Clare M; Lowery, Madeleine M; de Paor, Annraoi M

    2011-01-01

    Deep brain stimulation (DBS) effectively alleviates the pathological neural activity associated with Parkinson's disease. Its exact mode of action is not entirely understood. This paper explores theoretically the optimum stimulation parameters necessary to quench oscillations in a neural-mass type model with second order dynamics. This model applies well established nonlinear control system theory to DBS. The analysis here determines the minimum criteria in terms of amplitude and pulse duration of stimulation, necessary to quench the unwanted oscillations in a closed loop system, and outlines the relationship between this model and the actual physiological system.

  10. Systematic Review of Parameters of Stimulation: Clinical Trial Design Characteristics and Motor Outcomes in Noninvasive Brain Stimulation in Stroke

    Directory of Open Access Journals (Sweden)

    Bamidele Oyebamiji Adeyemo

    2012-11-01

    Full Text Available Introduction: Repetitive Transcranial Magnetic Stimulation (rTMS and Transcranial Direct Current Stimulation are two powerful non-invasive neuromodulatory therapies that have the potential to alter and evaluate the integrity of the corticospinal tract. Moreover, recent evidence has shown that brain stimulation might be beneficial in stroke recovery. Therefore, investigating and investing in innovative therapies that may improve neurorehabilitative stroke recovery are next steps in research and development.Methods: This article presents an up-to-date systematic review of the treatment effects of rTMS and tDCS on motor function. A literary search was conducted, utilizing search terms stroke and transcranial stimulation. Items were excluded if they failed to: (1 include stroke patients, (2 study motor outcomes, or (3 include rTMS/tDCS as treatments. Other exclusions included: (1 reviews, editorials, and letters, (2 animal or pediatric populations, (3 case reports or sample sizes < or = 2 patients, and (4 primary outcomes of dysphagia, dysarthria, neglect, or swallowing.Results: Investigation of PubMed English Database prior to 01/01/2012 produced 695 applicable results. Studies were excluded based on the aforementioned criteria, resulting in 50 remaining studies. They included 1314 participants (1282 stroke patients and 32 healthy subjects evaluated by motor function pre- and post- tDCS or rTMS. Heterogeneity among studies’ motor assessments was high and could not be accounted for by individual comparison. Pooled effect sizes for the impact of post-treatment improvement revealed consistently demonstrable improvements after tDCS and rTMS therapeutic stimulation. Most studies provided limited follow-up for long-term effects.Conclusions: It is apparent from the available studies that noninvasive stimulation may enhance motor recovery and may lead to clinically-meaningful functional improvements in the stroke population.

  11. Study of intracranial pressure in human brain during transcranial magnetic stimulation.

    Science.gov (United States)

    Honrath, Marc; Sabouni, Abas

    2015-01-01

    This paper presents the results of cranial force in human brain due to electromagnetic pulse during transcranial magnetic stimulation. To model the force in a realistic brain, we used three dimensional magnetic resonance image of the 26 years old female subject. Simulation results show that during TMS procedure, there is a small force generated within the cranial tissue layers along with a torque value in different layers of brain tissues. The force depends on the magnitude of the magnetic field generated by the TMS coil.

  12. The effects of subthalamic deep brain stimulation on metaphor comprehension and language abilities in Parkinson's disease.

    Science.gov (United States)

    Tremblay, Christina; Macoir, Joël; Langlois, Mélanie; Cantin, Léo; Prud'homme, Michel; Monetta, Laura

    2015-02-01

    The effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) on different language abilities are still controversial and its impact on high-level language abilities such as metaphor comprehension has been overlooked. The aim of this study was to determine the effects of STN electrical stimulation on metaphor comprehension and language abilities such as lexical and semantic capacities. Eight PD individuals with bilateral STN-DBS were first evaluated OFF-DBS and, at least seven weeks later, ON-DBS. Performance on metaphor comprehension, lexical decision, word association and verbal fluency tasks were compared ON and OFF-DBS in addition to motor symptoms evaluation. STN stimulation had a significant beneficial effect on motor symptoms in PD. However, this stimulation did not have any effect on metaphor comprehension or any other cognitive ability evaluated in this study. These outcomes suggest that STN stimulation may have dissociable effects on motor and language functions.

  13. Electron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profile

    Science.gov (United States)

    Kumsa, Doe W.; Bhadra, Narendra; Hudak, Eric M.; Kelley, Shawn C.; Untereker, Darrel F.; Mortimer, J. Thomas

    2016-10-01

    The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs-1, approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.

  14. Electron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profile.

    Science.gov (United States)

    Kumsa, Doe W; Bhadra, Narendra; Hudak, Eric M; Kelley, Shawn C; Untereker, Darrel F; Mortimer, J Thomas

    2016-10-01

    The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.

  15. Deep brain stimulation versus motor cortex stimulation for neuropathic pain: A minireview of the literature and proposal for future research.

    Science.gov (United States)

    Honey, C Michael; Tronnier, Volker M; Honey, Christopher R

    2016-01-01

    The treatment of neuropathic pain remains a public health concern. A growing cohort of patients is plagued by medically refractory, unrelenting severe neuropathic pain that ruins their quality of life and productivity. For this group, neurosurgery can offer two different kinds of neuromodulation that may help: deep brain simulation (DBS) and motor cortex stimulation (MCS). Unfortunately, there is no consensus on how to perform these procedures, which stimulation parameters to select, how to measure success, and which patients may benefit. This brief review highlights the literature supporting each technique and attempts to provide some comparisons and contrasts between DBS and MCS for the treatment of neuropathic pain. Finally, we highlight the current unanswered questions in the field and suggest future research strategies that may advance the care of our patients with neuropathic pain.

  16. Evaluation of local electric fields generated by transcranial direct current stimulation with an extracephalic reference electrode based on realistic 3D body modeling

    Science.gov (United States)

    Im, Chang-Hwan; Park, Ji-Hye; Shim, Miseon; Chang, Won Hyuk; Kim, Yun-Hee

    2012-04-01

    In this study, local electric field distributions generated by transcranial direct current stimulation (tDCS) with an extracephalic reference electrode were evaluated to address extracephalic tDCS safety issues. To this aim, we generated a numerical model of an adult male human upper body and applied the 3D finite element method to electric current conduction analysis. In our simulations, the active electrode was placed over the left primary motor cortex (M1) and the reference electrode was placed at six different locations: over the right temporal lobe, on the right supraorbital region, on the right deltoid, on the left deltoid, under the chin, and on the right buccinator muscle. The maximum current density and electric field intensity values in the brainstem generated by the extracephalic reference electrodes were comparable to, or even less than, those generated by the cephalic reference electrodes. These results suggest that extracephalic reference electrodes do not lead to unwanted modulation of the brainstem cardio-respiratory and autonomic centers, as indicated by recent experimental studies. The volume energy density was concentrated at the neck area by the use of deltoid reference electrodes, but was still smaller than that around the active electrode locations. In addition, the distributions of elicited cortical electric fields demonstrated that the use of extracephalic reference electrodes might allow for the robust prediction of cortical modulations with little dependence on the reference electrode locations.

  17. Relations among threshold, spike height, electrode distance, and conduction velocity in electrical stimulation of certain medullospinal neurons.

    Science.gov (United States)

    Hentall, I D; Zorman, G; Kansky, S; Fields, H L

    1984-05-01

    This report describes how the threshold for extracellular, electrical stimulation of cell bodies in the rat's rostromedial medulla depends on the distance to the stimulating electrode. A monopolar microelectrode both delivered current pulses near medullospinal neurons and, after decay of the stimulus artifact, detected whether an orthodromic spike had occurred by collision of that spike with a suitably timed antidromic spike initiated at the thoracic spinal cord. The liminal current and the height of antidromic spikes were noted at a series of vertical electrode positions. Regression analysis was performed to determine whether threshold and the inverse of peak-to-peak spike height varied more as the radial distance or its square. The square relationship provided a much better fit for threshold and a marginally better fit for the inverse of spike height. The spatial decline in excitability (K2) averaged 859 microA/mm2, falling within the range of values found for fibers and cell bodies in other studies. The constant of spatial decline in spike height (C2) in millivolts per square millimeter was positively correlated with K2. Both C2 and K2 were negatively correlated with conduction velocity. From threshold distance curves fitted by regression analysis, the mean separation of sites of spike maxima and threshold minima along each electrode path was 16 micron; the estimated distance from these sites to, respectively, the loci of spike generation and spike excitation were positively correlated and similar. The variation of C2 and K2 with conduction velocity may be due either to an influence of the size and shape of the dendritic tree on the spatial decrement of excitability and spike height or to a confounding in the studied equations of the space-independent effect of the size of a cell body on spike height and excitability.

  18. Tremor Reduction by Deep Brain Stimulation Is Associated With Gamma Power Suppression in Parkinson's Disease

    NARCIS (Netherlands)

    Beudel, Martijn; Little, Simon; Pogosyan, Alek; Ashkan, Keyoumars; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Bogdanovic, Marko; Cheeran, Binith; Green, Alexander L.; Aziz, Tipu; Thevathasan, Wesley; Brown, Peter

    2015-01-01

    Objectives: Rest tremor is a cardinal symptom of Parkinson's disease (PD), and is readily suppressed by deep brain stimulation (DBS) of the subthalamic nucleus (STN). The therapeutic effect of the latter on bradykinesia and rigidity has been associated with the suppression of exaggerated beta (13-30

  19. Deep brain stimulation modulates synchrony within spatially and spectrally distinct resting state networks in Parkinson's disease

    NARCIS (Netherlands)

    Oswal, Ashwini; Beudel, Martijn; Zrinzo, Ludvic; Limousin, Patricia; Hariz, Marwan; Foltynie, Tom; Litvak, Vladimir; Brown, Peter

    2016-01-01

    Chronic dopamine depletion in Parkinson's disease leads to progressive motor and cognitive impairment, which is associated with the emergence of characteristic patterns of synchronous oscillatory activity within cortico-basal-ganglia circuits. Deep brain stimulation of the subthalamic nucleus is an

  20. Rest and action tremor in Parkinson's disease: effects of Deep Brain Stimulation

    NARCIS (Netherlands)

    Heida, T.; Wentink, E.C.

    2010-01-01

    One of the cardinal symptoms of Parkinson’s disease is rest tremor. While rest tremor generally disappears during sleep and voluntary movement, action tremor may be triggered by voluntary movement, and may even be more disabling than rest tremor. Deep brain stimulation (DBS) in the subthalamic nucle

  1. Current Directions in Non-Invasive Low Intensity Electric Brain Stimulation for Depressive Disorder

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Sack, A.T.

    2014-01-01

    Non-invasive stimulation of the human brain to improve depressive symptoms is increasingly finding its way in clinical settings as a viable form of somatic treatment. Following successful modulation of neural excitability with subsequent antidepressant effects, neural polarization by administrating

  2. Effect of Transcranial Brain Stimulation for the Treatment of Alzheimer Disease: A Review

    OpenAIRE

    Raffaele Nardone; Jürgen Bergmann; Monica Christova; Francesca Caleri; Frediano Tezzon; Gunther Ladurner; Eugen Trinka; Stefan Golaszewski

    2011-01-01

    Available pharmacological treatments for Alzheimer disease (AD) have limited effectiveness, are expensive, and sometimes induce side effects. Therefore, alternative or complementary adjuvant therapeutic strategies have gained increasing attention. The development of novel noninvasive methods of brain stimulation has increased the interest in neuromodulatory techniques as potential therapeutic tool for cognitive rehabilitation in AD. In particular, repetitive transcranial magnetic stimulat...

  3. European clinical guidelines for Tourette syndrome and other tic disorders. Part IV : deep brain stimulation

    NARCIS (Netherlands)

    Mueller-Vahl, Kirsten R.; Cath, Danielle C.; Cavanna, Andrea E.; Dehning, Sandra; Porta, Mauro; Robertson, Mary M.; Visser-Vandewalle, Veerle

    2011-01-01

    Ten years ago deep brain stimulation (DBS) has been introduced as an alternative and promising treatment option for patients suffering from severe Tourette syndrome (TS). It seemed timely to develop a European guideline on DBS by a working group of the European Society for the Study of Tourette Synd

  4. High resolution functional photoacoustic computed tomography of the mouse brain during electrical stimulation

    Science.gov (United States)

    Avanaki, Mohammad R. N.; Xia, Jun; Wang, Lihong V.

    2013-03-01

    Photoacoustic computed tomography (PACT) is an emerging imaging technique which is based on the acoustic detection of optical absorption from tissue chromophores, such as oxy-hemoglobin and deoxy-hemoglobin. An important application of PACT is functional brain imaging of small animals. The conversion of light to acoustic waves allows PACT to provide high resolution images of cortical vasculatures through the intact scalp. Here, PACT was utilized to study the activated areas of the mouse brain during forepaw and hindpaw stimulations. Temporal PACT images were acquired enabling computation of hemodynamic changes during stimulation. The stimulations were performed by trains of pulses at different stimulation currents (between 0.1 to 2 mA) and pulse repetition rates (between 0.05 Hz to 0.01Hz). The response at somatosensory cortex-forelimb, and somatosensory cortex-hindlimb, were investigated. The Paxinos mouse brain atlas was used to confirm the activated regions. The study shows that PACT is a promising new technology that can be used to study brain functionality with high spatial resolution.

  5. Subthalamic Nucleus Deep Brain Stimulation Changes Velopharyngeal Control in Parkinson's Disease

    Science.gov (United States)

    Hammer, Michael J.; Barlow, Steven M.; Lyons, Kelly E.; Pahwa, Rajesh

    2011-01-01

    Purpose: Adequate velopharyngeal control is essential for speech, but may be impaired in Parkinson's disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN DBS) improves limb function in PD, but the effects on velopharyngeal control remain unknown. We tested whether STN DBS would change aerodynamic measures of velopharyngeal…

  6. Deep brain stimulation for obsessive-compulsive disorders : long-term analysis of quality of life

    NARCIS (Netherlands)

    Ooms, Pieter; Mantione, Mariska; Figee, Martijn; Schuurman, P Richard; van den Munckhof, Pepijn; Denys, D.

    2014-01-01

    OBJECTIVE: To evaluate the long-term effects of deep brain stimulation (DBS) on quality of life (QOL) in therapy-refractory obsessive-compulsive disorder (OCD) patients. DESIGN: 16 patients who met Diagnostic and Statistical Manual of Mental Disorders (4th ed) (DSM-IV) criteria for OCD and were cons

  7. Using non-invasive brain stimulation to augment motor training-induced plasticity

    Directory of Open Access Journals (Sweden)

    Pascual-Leone Alvaro

    2009-03-01

    Full Text Available Abstract Therapies for motor recovery after stroke or traumatic brain injury are still not satisfactory. To date the best approach seems to be the intensive physical therapy. However the results are limited and functional gains are often minimal. The goal of motor training is to minimize functional disability and optimize functional motor recovery. This is thought to be achieved by modulation of plastic changes in the brain. Therefore, adjunct interventions that can augment the response of the motor system to the behavioural training might be useful to enhance the therapy-induced recovery in neurological populations. In this context, noninvasive brain stimulation appears to be an interesting option as an add-on intervention to standard physical therapies. Two non-invasive methods of inducing electrical currents into the brain have proved to be promising for inducing long-lasting plastic changes in motor systems: transcranial magnetic stimulation (TMS and transcranial direct current stimulation (tDCS. These techniques represent powerful methods for priming cortical excitability for a subsequent motor task, demand, or stimulation. Thus, their mutual use can optimize the plastic changes induced by motor practice, leading to more remarkable and outlasting clinical gains in rehabilitation. In this review we discuss how these techniques can enhance the effects of a behavioural intervention and the clinical evidence to date.

  8. Functional Circuitry Effect of Ventral Tegmental Area Deep Brain Stimulation: Imaging and Neurochemical Evidence of Mesocortical and Mesolimbic Pathway Modulation

    Science.gov (United States)

    Settell, Megan L.; Testini, Paola; Cho, Shinho; Lee, Jannifer H.; Blaha, Charles D.; Jo, Hang J.; Lee, Kendall H.; Min, Hoon-Ki

    2017-01-01

    Background: The ventral tegmental area (VTA), containing mesolimbic and mesocortical dopaminergic neurons, is implicated in processes involving reward, addiction, reinforcement, and learning, which are associated with a variety of neuropsychiatric disorders. Electrical stimulation of the VTA or the medial forebrain bundle and its projection target the nucleus accumbens (NAc) is reported to improve depressive symptoms in patients affected by severe, treatment-resistant major depressive disorder (MDD) and depressive-like symptoms in animal models of depression. Here we sought to determine the neuromodulatory effects of VTA deep brain stimulation (DBS) in a normal large animal model (swine) by combining neurochemical measurements with functional magnetic resonance imaging (fMRI). Methods: Animals (n = 8 swine) were implanted with a unilateral DBS electrode targeting the VTA. During stimulation (130 Hz frequency, 0.25 ms pulse width, and 3 V amplitude), fMRI was performed. Following fMRI, fast-scan cyclic voltammetry in combination with carbon fiber microelectrodes was performed to quantify VTA-DBS-evoked dopamine release in the ipsilateral NAc. In a subset of swine, the blood oxygen level-dependent (BOLD) percent change evoked by stimulation was performed at increasing voltages (1, 2, and 3 V). Results: A significant increase in VTA-DBS-evoked BOLD signal was found in the following regions: the ipsilateral dorsolateral prefrontal cortex, anterior and posterior cingulate, insula, premotor cortex, primary somatosensory cortex, and striatum. A decrease in the BOLD signal was also observed in the contralateral parahippocampal cortex, dorsolateral and anterior prefrontal cortex, insula, inferior temporal gyrus, and primary somatosensory cortex (Bonferroni-corrected positively correlated with stimulation amplitude. Conclusions: In this study, the modulation of the neural circuitry associated with VTA-DBS was characterized in a large animal. Our findings suggest that VTA

  9. Histamine H1 and endothelin ETB receptors mediate phospholipase D stimulation in rat brain hippocampal slices.

    Science.gov (United States)

    Sarri, E; Picatoste, F; Claro, E

    1995-08-01

    Different neurotransmitter receptor agonists [carbachol, serotonin, noradrenaline, histamine, endothelin-1, and trans-(1S,3R)-aminocyclopentyl-1,3-dicarboxylic acid (trans-ACPD)], known as stimuli of phospholipase C in brain tissue, were tested for phospholipase D stimulation in [32P]Pi-prelabeled rat brain cortical and hippocampal slices. The accumulation of [32P]phosphatidylethanol was measured as an index of phospholipase D-catalyzed transphosphatidylation in the presence of ethanol. Among the six neurotransmitter receptor agonists tested, only noradrenaline, histamine, endothelin-1, and trans-ACPD stimulated phospholipase D in hippocampus and cortex, an effect that was strictly dependent of the presence of millimolar extracellular calcium concentrations. The effect of histamine (EC50 18 microM) was inhibited by the H1 receptor antagonist mepyramine with a Ki constant of 0.7 nM and was resistant to H2 and H3 receptor antagonists (ranitidine and tioperamide, respectively). Endothelin-1-stimulated phospholipase D (EC50 44 nM) was not blocked by BQ-123, a specific antagonist of the ETA receptor. Endothelin-3 and the specific ETB receptor agonist safarotoxin 6c were also able to stimulate phospholipase D with efficacies similar to that of endothelin-1, and EC50 values of 16 and 3 nM, respectively. These results show that histamine and endothelin-1 stimulate phospholipase D in rat brain through H1 and ETB receptors, respectively.

  10. Patterned brain stimulation, what a framework with rhythmic and noisy components might tell us about recovery maximization

    Directory of Open Access Journals (Sweden)

    Sein eSchmidt

    2013-06-01

    Full Text Available Brain stimulation is having remarkable impact on clinical neurology. Brain stimulation can modulate neuronal activity in functionally segregated circumscribed regions of the human brain. Polarity-, frequency and noise specific stimulation can induce specific manipulations on neural activity.. In contrast to neocortical stimulation, deep-brain stimulation has become a tool that can dramatically improve the impact clinicians can possibly have on movement disorders. In contrast, neocortical brain stimulation is proving to be remarkably susceptible to intrinsic brain-states. Although evidence is accumulating that brain stimulation can facilitate recovery processes in patients with cerebral stroke, the high variability of results impedes successful clinical implementation. Interestingly, recent data in healthy subjects suggests that brain-state dependent patterned stimulation might help resolve some of the intrinsic variability found in previous studies. In parallel, other studies suggest that noisy stochastic resonance -like processes are a non-negligible component in NBS studies.The hypothesis developed in this manuscript is that stimulation patterning with noisy and oscillatory components will help patients recover from stroke related deficits more reliably. To address this hypothesis we focus on two factors common to both neural computation (intrinsic variables as well as brain stimulation (extrinsic variables: noise and oscillation. We review diverse theoretical and experimental evidence that demonstrates that subject-function specific brain-states are associated with specific oscillatory activity patterns. These states are transient and can be maintained by noisy processes. The resulting control procedures can resemble homeostatic or stochastic resonance processes. In this context we try to extend awareness for inter-individual differences and the use of individualized stimulation in the recovery maximization of stroke patients.

  11. How does transcranial magnetic stimulation modify neuronal activity in the brain? Implications for studies of cognition

    DEFF Research Database (Denmark)

    Siebner, Hartwig R; Hartwigsen, Gesa; Kassuba, Tanja

    2009-01-01

    Transcranial magnetic stimulation (TMS) uses a magnetic field to "carry" a short lasting electrical current pulse into the brain where it stimulates neurones, particularly in superficial regions of cerebral cortex. TMS can interfere with cognitive functions in two ways. A high intensity TMS pulse...... in the human brain. This transient neurodisruption has been termed a "virtual lesion". Smaller intensities of stimulation produce less activity; in such cases, cognitive operations can probably continue but are disrupted because of the added noisy input from the TMS pulse. It is usually argued that if a TMS...... causes a synchronised high frequency burst of discharge in a relatively large population of neurones that is terminated by a long lasting GABAergic inhibition. The combination of artificial synchronisation of activity followed by depression effectively disrupts perceptual, motor and cognitive processes...

  12. Limbic, associative, and motor territories within the targets for deep brain stimulation: potential clinical implications.

    Science.gov (United States)

    Sudhyadhom, Atchar; Bova, Frank J; Foote, Kelly D; Rosado, Christian A; Kirsch-Darrow, Lindsey; Okun, Michael S

    2007-07-01

    The use of deep brain stimulation (DBS) has recently been expanding for the treatment of many neurologic disorders such as Parkinson disease, dystonia, essential tremor, Tourette's syndrome, cluster headache, epilepsy, depression, and obsessive compulsive disorder. The target structures for DBS include specific segregated territories within limbic, associative, or motor regions of very small subnuclei. In this review, we summarize current clinical techniques for DBS, the cognitive/mood/motor outcomes, and the relevant neuroanatomy with respect to functional territories within specific brain targets. Future development of new techniques and technology that may include a more direct visualization of "motor" territories within target structures may prove useful for avoiding side effects that may result from stimulation of associative and limbic regions. Alternatively, newer procedures may choose and specifically target non-motor territories for chronic electrical stimulation.

  13. Brain stimulation used as biofeedback in neuronal activation of the temporal lobe area in autistic children

    Directory of Open Access Journals (Sweden)

    Vernon Furtado da Silva

    2016-08-01

    Full Text Available ABSTRACT This study focused upon the functional capacity of mirror neurons in autistic children. 30 individuals, 10 carriers of the autistic syndrome (GCA, 10 with intellectual impairments (GDI, and 10 non-autistics (GCN had registered eletroencephalogram from the brain area theoretically related to mirror neurons. Data collection procedure occurred prior to brain stimulation and after the stimulation session. During the second session, participants had to alternately process figures evoking neutral, happy, and/or sorrowful feelings. Results proved that, for all groups, the stimulation process in fact produced additional activation in the neural area under study. The level of activation was related to the format of emotional stimuli and the likelihood of boosting such stimuli. Since the increase of activation occurred in a model similar to the one observed for the control group, we may suggest that the difficulty people with autism have at expressing emotions is not due to nonexistence of mirror neurons.

  14. Affective Brain-Computer Interfaces As Enabling Technology for Responsive Psychiatric Stimulation.

    Science.gov (United States)

    Widge, Alik S; Dougherty, Darin D; Moritz, Chet T

    2014-04-01

    There is a pressing clinical need for responsive neurostimulators, which sense a patient's brain activity and deliver targeted electrical stimulation to suppress unwanted symptoms. This is particularly true in psychiatric illness, where symptoms can fluctuate throughout the day. Affective BCIs, which decode emotional experience from neural activity, are a candidate control signal for responsive stimulators targeting the limbic circuit. Present affective decoders, however, cannot yet distinguish pathologic from healthy emotional extremes. Indiscriminate stimulus delivery would reduce quality of life and may be actively harmful. We argue that the key to overcoming this limitation is to specifically decode volition, in particular the patient's intention to experience emotional regulation. Those emotion-regulation signals already exist in prefrontal cortex (PFC), and could be extracted with relatively simple BCI algorithms. We describe preliminary data from an animal model of PFC-controlled limbic brain stimulation and discuss next steps for pre-clinical testing and possible translation.

  15. A case of musical preference for Johnny Cash following deep brain stimulation of the nucleus accumbens

    Directory of Open Access Journals (Sweden)

    Mariska eMantione

    2014-05-01

    Full Text Available Music is among all cultures an important part of the live of most people. Music has psychological benefits and may generate strong emotional and physiological responses. Recently, neuroscientists have discovered that music influences the reward circuit of the nucleus accumbens, even when no explicit reward is present. In this clinical case study, we describe a 60-year old patient who developed a sudden and distinct musical preference for Johnny Cash following deep brain stimulation targeted at the nucleus accumbens for treatment-refractory obsessive-compulsive disorder. This case report substantiates the assumption that the nucleus accumbens is involved in musical preference, based on the observation of direct stimulation of the accumbens with deep brain stimulation. It also shows that accumbens DBS can change musical preference without habituation of its rewarding properties.

  16. Abnormal hemodynamic response to forepaw stimulation in rat brain after cocaine injection

    Science.gov (United States)

    Chen, Wei; Park, Kicheon; Choi, Jeonghun; Pan, Yingtian; Du, Congwu

    2015-03-01

    Simultaneous measurement of hemodynamics is of great importance to evaluate the brain functional changes induced by brain diseases such as drug addiction. Previously, we developed a multimodal-imaging platform (OFI) which combined laser speckle contrast imaging with multi-wavelength imaging to simultaneously characterize the changes in cerebral blood flow (CBF), oxygenated- and deoxygenated- hemoglobin (HbO and HbR) from animal brain. Recently, we upgraded our OFI system that enables detection of hemodynamic changes in response to forepaw electrical stimulation to study potential brain activity changes elicited by cocaine. The improvement includes 1) high sensitivity to detect the cortical response to single forepaw electrical stimulation; 2) high temporal resolution (i.e., 16Hz/channel) to resolve dynamic variations in drug-delivery study; 3) high spatial resolution to separate the stimulation-evoked hemodynamic changes in vascular compartments from those in tissue. The system was validated by imaging the hemodynamic responses to the forepaw-stimulations in the somatosensory cortex of cocaine-treated rats. The stimulations and acquisitions were conducted every 2min over 40min, i.e., from 10min before (baseline) to 30min after cocaine challenge. Our results show that the HbO response decreased first (at ~4min) followed by the decrease of HbR response (at ~6min) after cocaine, and both did not fully recovered for over 30min. Interestingly, while CBF decreased at 4min, it partially recovered at 18min after cocaine administration. The results indicate the heterogeneity of cocaine's effects on vasculature and tissue metabolism, demonstrating the unique capability of optical imaging for brain functional studies.

  17. Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain

    Directory of Open Access Journals (Sweden)

    Zhan-chi Zhang

    2015-01-01

    Full Text Available In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers, to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  18. Low-frequency transcranial magnetic stimulation is beneifcial for enhancing synaptic plasticity in the aging brain

    Institute of Scientific and Technical Information of China (English)

    Zhan-chi Zhang; Feng Luan; Chun-yan Xie; Dan-dan Geng; Yan-yong Wang; Jun Ma

    2015-01-01

    In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz) ameliorates synaptic plasticity and spatial cognitive deifcits in learning-im-paired mice. However, the mechanisms by which this treatment improves these deifcits during normal aging are still unknown. Therefore, the current study investigated the effects of tran-scranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, syn-aptophysin and growth-associated protein 43 (both synaptic markers), to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcra-nial magnetic stimulation with low intensity (110%average resting motor threshold intensity, 1 Hz) increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippo-campus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this reg-ulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  19. Alteration of political belief by non- invasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Caroline eChawke

    2016-01-01

    Full Text Available People generally have imperfect introspective access to the mechanisms underlying their political beliefs, yet can confidently communicate the reasoning that goes into their decision making process. An innate desire for certainty and security in ones beliefs may play an important and somewhat automatic role in motivating the maintenance or rejection of partisan support. The aim of the current study was to clarify the role of the DLPFC in the alteration of political beliefs. Recent neuroimaging studies have focused on the association between the DLPFC (a region involved in the regulation of cognitive conflict and error feedback processing and reduced affiliation with opposing political candidates. As such, this study used a method of non- invasive brain simulation (tRNS to enhance activity of the bilateral DLPFC during the incorporation of political campaign information. These findings indicate a crucial role for this region in political belief formation. However, enhanced activation of DLPFC does not necessarily result in the specific rejection of political beliefs. In contrast to the hypothesis the results appear to indicate a significant increase in conservative values regardless of participant’s initial political orientation and the political campaign advertisement they were exposed to.

  20. Alteration of Political Belief by Non-invasive Brain Stimulation.

    Science.gov (United States)

    Chawke, Caroline; Kanai, Ryota

    2015-01-01

    People generally have imperfect introspective access to the mechanisms underlying their political beliefs, yet can confidently communicate the reasoning that goes into their decision making process. An innate desire for certainty and security in ones beliefs may play an important and somewhat automatic role in motivating the maintenance or rejection of partisan support. The aim of the current study was to clarify the role of the DLPFC in the alteration of political beliefs. Recent neuroimaging studies have focused on the association between the DLPFC (a region involved in the regulation of cognitive conflict and error feedback processing) and reduced affiliation with opposing political candidates. As such, this study used a method of non-invasive brain simulation (tRNS) to enhance activity of the bilateral DLPFC during the incorporation of political campaign information. These findings indicate a crucial role for this region in political belief formation. However, enhanced activation of DLPFC does not necessarily result in the specific rejection of political beliefs. In contrast to the hypothesis the results appear to indicate a significant increase in conservative values regardless of participant's initial political orientation and the political campaign advertisement they were exposed to.

  1. Optimizing a Rodent Model of Parkinson's Disease for Exploring the Effects and Mechanisms of Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Karl Nowak

    2011-01-01

    instrumented rats carrying a backpack stimulator and implanted platinum/iridium electrodes. This model is suitable for (1 elucidating the electrochemical processes at the electrode/tissue interface, (2 analyzing the molecular, cellular and behavioral stimulation effects, (3 testing new target regions for DBS, (4 screening for potential neuroprotective DBS effects, and (5 improving the efficacy and safety of the method. An outlook is given on further developments of experimental DBS, including the use of transgenic animals and the testing of closed-loop systems for the direct on-demand application of electric stimulation.

  2. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction – a Finite Element Simulation Study

    Science.gov (United States)

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-08-01

    Hemorrhagic shock accounts for 30–40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach.

  3. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction - a Finite Element Simulation Study.

    Science.gov (United States)

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-08-18

    Hemorrhagic shock accounts for 30-40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach.

  4. Transfer of cognitive training across magnitude dimensions achieved with concurrent brain stimulation of the parietal lobe.

    Science.gov (United States)

    Cappelletti, Marinella; Gessaroli, Erica; Hithersay, Rosalyn; Mitolo, Micaela; Didino, Daniele; Kanai, Ryota; Cohen Kadosh, Roi; Walsh, Vincent

    2013-09-11

    Improvement in performance following cognitive training is known to be further enhanced when coupled with brain stimulation. Here we ask whether training-induced changes can be maintained long term and, crucially, whether they can extend to other related but untrained skills. We trained overall 40 human participants on a simple and well established paradigm assessing the ability to discriminate numerosity--or the number of items in a set--which is thought to rely on an "approximate number sense" (ANS) associated with parietal lobes. We coupled training with parietal stimulation in the form of transcranial random noise stimulation (tRNS), a noninvasive technique that modulates neural activity. This yielded significantly better and longer lasting improvement (up to 16 weeks post-training) of the precision of the ANS compared with cognitive training in absence of stimulation, stimulation in absence of cognitive training, and cognitive training coupled to stimulation to a control site (motor areas). Critically, only ANS improvement induced by parietal tRNS + Training transferred to proficiency in other parietal lobe-based quantity judgment, i.e., time and space discrimination, but not to quantity-unrelated tasks measuring attention, executive functions, and visual pattern recognition. These results indicate that coupling intensive cognitive training with tRNS to critical brain regions resulted not only in the greatest and longer lasting improvement of numerosity discrimination, but importantly in this enhancement being transferable when trained and untrained abilities are carefully chosen to share common cognitive and neuronal components.

  5. Augmented brain function by coordinated reset stimulation with slowly varying sequences

    Directory of Open Access Journals (Sweden)

    Magteld eZeitler

    2015-03-01

    Full Text Available Several brain disorders are characterized by abnormally strong neuronal synchrony. Coordinated Reset (CR stimulation was developed to selectively counteract abnormal neuronal synchrony by desynchronization. For this, phase resetting stimuli are delivered to different subpopulations in a timely coordinated way. In neural networks with spike timing-dependent plasticity CR stimulation may eventually lead to an anti-kindling, i.e. an unlearning of abnormal synaptic connectivity and abnormal synchrony. The spatiotemporal sequence by which all stimulation sites are stimulated exactly once is called the stimulation site sequence, or briefly sequence. So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS. In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR. To this end, a sequence is applied many times before randomly switching to the next sequence. This new method is called SVS CR stimulation, i.e. CR with slowly varying sequences. In a neuronal network with strong short-range excitatory and weak long-range inhibitory dynamic couplings SVS CR stimulation turns out to be superior to CR stimulation with fixed sequences or RVS.

  6. A monolithic integrated low-voltage deep brain stimulator with wireless power and data transmission

    Science.gov (United States)

    Zhang, Zhang; Ye, Tan; Jianmin, Zeng; Xu, Han; Xin, Cheng; Guangjun, Xie

    2016-09-01

    A monolithic integrated low-voltage deep brain stimulator with wireless power and data transmission is presented. Data and power are transmitted to the stimulator by mutual inductance coupling, while the in-vitro controller encodes the stimulation parameters. The stimulator integrates the digital control module and can generate the bipolar current with equal amplitude in four channels. In order to reduce power consumption, a novel controlled threshold voltage cancellation rectifier is proposed in this paper to provide the supply voltage of the stimulator. The monolithic stimulator was fabricated in a SMIC 0.18 μm 1-poly 6-metal mixed-signal CMOS process, occupying 0.23 mm2, and consumes 180 μW on average. Compared with previously published stimulators, this design has advantages of large stimulated current (0-0.8 mA) with the double low-voltage supply (1.8 and 3.3 V), and high-level integration. Project supported by the National Natural Science Foundation of China (Nos. 61404043, 61401137), the Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (Nos. IIMDKFJJ-13-06, IIMDKFJJ-14-03), and the Fundamental Research Funds for the Central Universities (No. 2015HGZX0026).

  7. Weight gain following subthalamic nucleus deep brain stimulation: a PET study.

    Science.gov (United States)

    Sauleau, Paul; Le Jeune, Florence; Drapier, Sophie; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Lalys, Florent; Robert, Gabriel; Drapier, Dominique; Vérin, Marc

    2014-12-01

    Several hypotheses have been put forward to explain weight gain after deep brain stimulation (DBS), but none provides a fully satisfactory account of this adverse effect. We analyzed the correlation between changes in brain metabolism (using positron emission tomography [PET] imaging) and weight gain after bilateral subthalamic nucleus DBS in patients with Parkinson's disease. Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose 3 months before and 4 months after the start of subthalamic nucleus deep brain stimulation in 23 patients with Parkinson's disease. Motor complications (United Parkinson's Disease Rating Scale [UPDRS]-IV scores) and dopaminergic medication were included in the analysis to control for their possible influence on brain metabolism. Mean ± standard deviation (SD) body mass index increased significantly by 0.8 ± 1.5 kg/m(2) (P = 0.03). Correlations were found between weight gain and changes in brain metabolism in limbic and associative areas, including the orbitofrontal cortex (Brodmann areas [BAs] 10 and 11), lateral and medial parts of the temporal lobe (BAs 20, 21, 22,39 and 42), anterior cingulate cortex (BA 32), and retrosplenial cortex (BA 30). However, we found no correlation between weight gain and metabolic changes in sensorimotor areas. These findings suggest that changes in associative and limbic processes contribute to weight gain after subthalamic nucleus DBS in Parkinson's disease.

  8. Midbrain raphe stimulation improves behavioral and anatomical recovery from fluid-percussion brain injury.

    Science.gov (United States)

    Carballosa Gonzalez, Melissa M; Blaya, Meghan O; Alonso, Ofelia F; Bramlett, Helen M; Hentall, Ian D

    2013-01-15

    The midbrain median raphe (MR) and dorsal raphe (DR) nuclei were tested for their capacity to regulate recovery from traumatic brain injury (TBI). An implanted, wireless self-powered stimulator delivered intermittent 8-Hz pulse trains for 7 days to the rat's MR or DR, beginning 4-6 h after a moderate parasagittal (right) fluid-percussion injury. MR stimulation was also examined with a higher frequency (24 Hz) or a delayed start (7 days after injury). Controls had sham injuries, inactive stimulators, or both. The stimulation caused no apparent acute responses or adverse long-term changes. In water-maze trials conducted 5 weeks post-injury, early 8-Hz MR and DR stimulation restored the rate of acquisition of reference memory for a hidden platform of fixed location. Short-term spatial working memory, for a variably located hidden platform, was restored only by early 8-Hz MR stimulation. All stimulation protocols reversed injury-induced asymmetry of spontaneous forelimb reaching movements tested 6 weeks post-injury. Post-mortem histological measurement at 8 weeks post-injury revealed volume losses in parietal-occipital cortex and decussating white matter (corpus callosum plus external capsule), but not hippocampus. The cortical losses were significantly reversed by early 8-Hz MR and DR stimulation, the white matter losses by all forms of MR stimulation. The generally most effective protocol, 8-Hz MR stimulation, was tested 3 days post-injury for its acute effect on forebrain cyclic adenosine monophosphate (cAMP), a key trophic signaling molecule. This procedure reversed injury-induced declines of cAMP levels in both cortex and hippocampus. In conclusion, midbrain raphe nuclei can enduringly enhance recovery from early disseminated TBI, possibly in part through increased signaling by cAMP in efferent targets. A neurosurgical treatment for TBI using interim electrical stimulation in raphe repair centers is suggested.

  9. Numeric Investigation of Brain Tumor Influence on the Current Distributions During Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Song, Bo; Wen, Peng; Ahfock, Tony; Li, Yan

    2016-01-01

    This study constructed a series of high-resolution realistic human-head models with brain tumors, and numerically investigated the influence of brain tumor's location and grade on the current distributions, under different electrode montages during tDCS. The threshold area and the peak current density were also derived and analyzed in the region of interest. The simulation result showed that it is safe to apply tDCS on the patients with brain tumors to treat their neuropsychiatric conditions and cancer pain caused by the tumor; although considerable changes of the current distributions are induced by the presence of a brain tumor. In addition, several observations on the global and local influences of tumor grade and possible edema have been made as well. These findings should be helpful for researchers and clinical doctors to treat patients with brain tumors. This study is also the first numerical study to fill in the gap of tDCS applications on the patients with brain tumors.

  10. Repetitive transcranial magnetic stimulation for the treatment of chronic tinnitus after traumatic brain injury: a case study.

    Science.gov (United States)

    Kreuzer, Peter Michael; Landgrebe, Michael; Frank, Elmar; Langguth, Berthold

    2013-01-01

    Tinnitus is a frequent symptom of traumatic brain injury, which is difficult to treat. Repetitive transcranial magnetic stimulation has shown beneficial effects in some forms of tinnitus. However, traumatic brain injury in the past has been considered as a relative contraindication for repetitive transcranial magnetic stimulation because of the increased risk of seizures. Here we present the case of a 53-year-old male patient suffering from severe tinnitus after traumatic brain injury with comorbid depression and alcohol abuse, who received 5 treatment series of repetitive transcranial magnetic stimulation (1 Hz stimulation protocol over left primary auditory cortex, 10 sessions of 2000 stimuli each, stimulation intensity 110% resting motor threshold). Repetitive transcranial magnetic stimulation was tolerated without any side effects and tinnitus complaints (measured by a validated tinnitus questionnaire and numeric rating scales) were improved in a replicable way throughout 5 courses of transcranial magnetic stimulation up to now.

  11. Moving Forward By Stimulating the Brain: Transcranial Direct Current Stimulation in Post-Stroke Hemiparesis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Heather T. Peters

    2016-08-01

    Full Text Available Stroke remains a leading cause of disability worldwide, with a majority of survivors experiencing long term decrements in motor function that severely undermine quality of life. While many treatment approaches and adjunctive strategies exist to remediate motor impairment, many are only efficacious or feasible for survivors with active hand and wrist function, a population who constitute only a minority of stroke survivors. Transcranial direct current stimulation (tDCS, a type of noninvasive brain stimulation, has been increasingly utilized to increase motor function following stroke as it is able to be used with stroke survivors of varying impairment levels, is portable, is relatively inexpensive and has few side effects and contraindications. Accordingly, in recent years the number of studies investigating its efficacy when utilized as an adjunct to motor rehabilitation regimens has drastically increased. While many of these trials have reported positive and promising efficacy, methodologies vary greatly between studies, including differences in stimulation parameters, outcome measures and the nature of physical practice. As such, an urgent need remains, centering on the need to investigate these methodological differences and synthesize the most current evidence surrounding the application of tDCS for post-stroke motor rehabilitation. Accordingly, the purpose of this paper is to provide a detailed overview of the most recent tDCS literature (published 2014-2015, while highlighting these variations in methodological approach, as well to elucidate the mechanisms associated with tDCS and post-stroke motor re-learning and neuroplasticity.

  12. Parkinson's disease patients with bilateral subthalamic deep brain stimulation gain weight.

    Science.gov (United States)

    Macia, Frédéric; Perlemoine, Caroline; Coman, Irène; Guehl, Dominique; Burbaud, Pierre; Cuny, Emmanuel; Gin, Henri; Rigalleau, Vincent; Tison, François

    2004-02-01

    Weight, body mass index (BMI) and energy expenditure/energy intake (EE/EI) was studied in 19 Parkinson's disease (PD) patients after subthalamic deep brain stimulation (STN-DBS) versus 14 nonoperated ones. Operated patients had a significant weight gain (WG, + 9.7 +/- 7 kg) and BMI increase (+ 4.7 kg/m2). The fat mass was higher after STN-DBS. Resting EE (REE; offdrug/ON stimulation) was significantly decreased in STN-DBS patients, while their daily energy expenditure (DEI) was not significantly different. A significant correlation was found among WG, BMI increase, and pre-operative levodopa-equivalent daily dose, their reduction after STN-DBS, and the differential REE related to stimulation and the REE in the offdrug/OFF stimulation condition. In conclusion, STN-DBS in PD induces a significant WG associated with a reduction in REE without DEI adjustment.

  13. MRI Guided Brain Stimulation without the Use of a Neuronavigation System

    Directory of Open Access Journals (Sweden)

    Ehsan Vaghefi

    2015-01-01

    Full Text Available A key issue in the field of noninvasive brain stimulation (NIBS is the accurate localization of scalp positions that correspond to targeted cortical areas. The current gold standard is to combine structural and functional brain imaging with a commercially available “neuronavigation” system. However, neuronavigation systems are not commonplace outside of specialized research environments. Here we describe a technique that allows for the use of participant-specific functional and structural MRI data to guide NIBS without a neuronavigation system. Surface mesh representations of the head were generated using Brain Voyager and vectors linking key anatomical landmarks were drawn on the mesh. Our technique was then used to calculate the precise distances on the scalp corresponding to these vectors. These calculations were verified using actual measurements of the head and the technique was used to identify a scalp position corresponding to a brain area localized using functional MRI.

  14. Research progress of deep brain stimulation for the treatment of drug addiction

    Directory of Open Access Journals (Sweden)

    Lei CHEN

    2015-10-01

    Full Text Available Drug addiction is a serious problem all over the world involving both medical and social issues. The treatment strategy lies in two aspects, promoting detoxification and preventing relapse. The latter is the key for successful treatment. Although surgical measures, like stereotactic ablation of nucleusaccumbens (NAc, had already been proven to be effective for relapse prevention clinically, the application was restricted because of the damage to brain tissues. Deep brain stimulation (DBS, which had been successfully applied in movement disorders, was recently performed in addiction studies on both animals and humankind. Among numbers of brain areas related to addiction, NAc is the hottest target studied and may bring better clinical effect. In addition, combining stimulation of multiple brain targets is currently performed for relapse prevention. The mechanism of DBS for treatment of addiction remains unclear right now, however, DBS may be an experimental method to treat refractory addictive patients. Certainly, lots of problems need to be solved in large sample study before the wide application of DBS for addiction treatment, such as the setting of stimulation parameters, recognition of objective treatment feedback and ethical issues. DOI: 10.3969/j.issn.1672-6731.2015.10.004

  15. Improved sequence learning with subthalamic nucleus deep brain stimulation: evidence for treatment-specific network modulation.

    Science.gov (United States)

    Mure, Hideo; Tang, Chris C; Argyelan, Miklos; Ghilardi, Maria-Felice; Kaplitt, Michael G; Dhawan, Vijay; Eidelberg, David

    2012-02-22

    We used a network approach to study the effects of anti-parkinsonian treatment on motor sequence learning in humans. Eight Parkinson's disease (PD) patients with bilateral subthalamic nucleus (STN) deep brain stimulation underwent H(2)(15)O positron emission tomography (PET) imaging to measure regional cerebral blood flow (rCBF) while they performed kinematically matched sequence learning and movement tasks at baseline and during stimulation. Network analysis revealed a significant learning-related spatial covariance pattern characterized by consistent increases in subject expression during stimulation (p = 0.008, permutation test). The network was associated with increased activity in the lateral cerebellum, dorsal premotor cortex, and parahippocampal gyrus, with covarying reductions in the supplementary motor area (SMA) and orbitofrontal cortex. Stimulation-mediated increases in network activity correlated with concurrent improvement in learning performance (p learning performance or network activity. Analysis of learning-related rCBF in network regions revealed improvement in baseline abnormalities with STN stimulation but not levodopa. These effects were most pronounced in the SMA. In this region, a consistent rCBF response to stimulation was observed across subjects and trials (p = 0.01), although the levodopa response was not significant. These findings link the cognitive treatment response in PD to changes in the activity of a specific cerebello-premotor cortical network. Selective modulation of overactive SMA-STN projection pathways may underlie the improvement in learning found with stimulation.

  16. Deep brain stimulation in clinical trials and animal models of depression.

    Science.gov (United States)

    Hamani, Clement; Nóbrega, José N

    2010-10-01

    Deep brain stimulation (DBS) is currently being investigated as a therapy for the treatment of depression. Despite promising results of recent clinical trials, neural and chemical mechanisms responsible for the effects of stimulation are still unclear. In this article, we review clinical and laboratory findings on DBS for depression. Particular emphasis will be given to aspects involved in the translation of data from animal models to humans and in our findings on the potential substrates involved in the antidepressant effects of DBS in rats.

  17. Two-dimensional zymography differentiates gelatinase isoforms in stimulated microglial cells and in brain tissues of acute brain injuries.

    Science.gov (United States)

    Chen, Shanyan; Meng, Fanjun; Chen, Zhenzhou; Tomlinson, Brittany N; Wesley, Jennifer M; Sun, Grace Y; Whaley-Connell, Adam T; Sowers, James R; Cui, Jiankun; Gu, Zezong

    2015-01-01

    Excessive activation of gelatinases (MMP-2/-9) is a key cause of detrimental outcomes in neurodegenerative diseases. A single-dimension zymography has been widely used to determine gelatinase expression and activity, but this method is inadequate in resolving complex enzyme isoforms, because gelatinase expression and activity could be modified at transcriptional and posttranslational levels. In this study, we investigated gelatinase isoforms under in vitro and in vivo conditions using two-dimensional (2D) gelatin zymography electrophoresis, a protocol allowing separation of proteins based on isoelectric points (pI) and molecular weights. We observed organomercuric chemical 4-aminophenylmercuric acetate-induced activation of MMP-2 isoforms with variant pI values in the conditioned medium of human fibrosarcoma HT1080 cells. Studies with murine BV-2 microglial cells indicated a series of proform MMP-9 spots separated by variant pI values due to stimulation with lipopolysaccharide (LPS). The MMP-9 pI values were shifted after treatment with alkaline phosphatase, suggesting presence of phosphorylated isoforms due to the proinflammatory stimulation. Similar MMP-9 isoforms with variant pI values in the same molecular weight were also found in mouse brains after ischemic and traumatic brain injuries. In contrast, there was no detectable pI differentiation of MMP-9 in the brains of chronic Zucker obese rats. These results demonstrated effective use of 2D zymography to separate modified MMP isoforms with variant pI values and to detect posttranslational modifications under different pathological conditions.

  18. Evaluation of a Modified High-Definition Electrode Montage for Transcranial Alternating Current Stimulation (tACS) of Pre-Central Areas

    DEFF Research Database (Denmark)

    Heise, Kirstin Friederike; Kortzorg, Nick; Saturnino, Guilherme Bicalho;

    2016-01-01

    Objective: To evaluate a modified electrode montage with respect to its effect on tACS-dependent modulation of corticospinal excitability and discomfort caused by neurosensory side effects accompanying stimulation. Methods: In a double-blind cross-over design, the classical electrode montage...... random noise stimulation). Results: Corticospinal excitability increased significantly during and immediately after tACS with the centre-ring montage. This was not the case with the classical montage or tRNS stimulation. Level of discomfort was rated on average lower with the centre-ring montage....... Conclusions: In comparison to the classic montage, the M1 centre-ring montage enables a more focal stimulation of the target area and, at the same time, significantly reduces neurosensory side effects, essential for placebo-controlled study designs....

  19. Phase-dependent modulation as a novel approach for therapeutic brain stimulation

    Directory of Open Access Journals (Sweden)

    Ramin eAzodi-Avval

    2015-02-01

    Full Text Available Closed-loop paradigms provide us with the opportunity to optimize stimulation protocols for perturbation of pathological oscillatory activity in brain-related disorders. In this vein, spiking activity of motor cortex neurons and beta activity of local field potentials in the subthalamic nucleus have both been used independently of each other as neuronal signals to trigger deep brain stimulation for alleviating Parkinsonism. These approaches were superior to the standard continuous high-frequency stimulation protocols used in daily practice. However, they achieved their effects by bursts of stimulation that were applied at high-frequency as well, i.e. independent of the phase information in the stimulated region. In this context, we propose that, by timing stimulation pulses relative to the ongoing oscillation, an alternative approach, namely the targeted perturbation of pathological rhythms, could be obtained.In this modeling study, we first captured the underlying dynamics of neuronal oscillations in the human subthalamic nucleus by phased coupled neuronal oscillators. We then quantified the nature of the interaction between these coupled oscillators by obtaining a physiologically informed phase response curve from local field potentials. Reconstruction of the phase response curve predicted the sensitivity of the phase oscillator to external stimuli, revealing phase intervals that optimally maximized the degree of perturbation. We conclude that our specifically timed intervention based on the coupled oscillator concept will enable us to identify personalized ways of delivering stimulation pulses in closed-loop paradigms triggered by the phase of pathological oscillations. This will pave the way for novel physiological insights and substantial clinical benefits. In addition, this precisely phased modulation may be capable of modifying the effective interactions between oscillators in an entirely new manner.

  20. The reconstructive management of hardware-related scalp erosion in deep brain stimulation for Parkinson disease.

    Science.gov (United States)

    Gómez, Raúl; Hontanilla, Bernardo

    2014-09-01

    The presence of foreign material in deep brain stimulation is a risk factor for infection, and hardware-related pressure under the scalp may cause skin erosion. The aim of this article is to present our experience in the coverage of scalp in relation to underlying hardware. We analyzed 21 patients with Parkinson disease who had undergone deep brain stimulation surgery and developed scalp erosion with hardware exposition during follow-up. Nine patients were programmed for a scalp rotation flap, whereas free tisue transfer was performed in the rest of the patients. Minimum follow-up was 2 years. A hardware-related ulcer appeared in 5 of 9 rotation flap patients. No ulceration or major complications were observed in free flap patients. Free flaps are probably the best option for stable coverage in hardware-related scalp erosion with a high rate of success.

  1. Transcranial brain stimulation (TMS and tDCS for post-stroke aphasia rehabilitation: Controversies

    Directory of Open Access Journals (Sweden)

    Lucia Iracema Zanotto de Mendonça

    Full Text Available Transcranial brain stimulation (TS techniques have been investigated for use in the rehabilitation of post-stroke aphasia. According to previous reports, functional recovery by the left hemisphere improves recovery from aphasia, when compared with right hemisphere participation. TS has been applied to stimulate the activity of the left hemisphere or to inhibit homotopic areas in the right hemisphere. Various factors can interfere with the brain's response to TS, including the size and location of the lesion, the time elapsed since the causal event, and individual differences in the hemispheric language dominance pattern. The following questions are discussed in the present article: [a] Is inhibition of the right hemisphere truly beneficial?; [b] Is the transference of the language network to the left hemisphere truly desirable in all patients?; [c] Is the use of TS during the post-stroke subacute phase truly appropriate? Different patterns of neuroplasticity must occur in post-stroke aphasia.

  2. The world can look better: enhancing beauty experience with brain stimulation.

    Science.gov (United States)

    Cattaneo, Zaira; Lega, Carlotta; Flexas, Albert; Nadal, Marcos; Munar, Enric; Cela-Conde, Camilo J

    2014-11-01

    Aesthetic appreciation is part of our everyday life: it is a subjective judgment we make when looking at a painting, a landscape, or--in fact--at another person. Neuroimaging and electrophysiological evidence suggests that the left dorsolateral prefrontal cortex (DLPFC) plays a critical role in aesthetic judgments. Here, we show that the experience of beauty can be artificially enhanced with brain stimulation. Specifically, we show that aesthetic appreciation of representational paintings and photographs can be increased by applying anodal (excitatory) transcranial direct current stimulation on the left DLPFC. Our results thus show that beauty is in the brain of the beholder, and offer a novel view on the neural networks underlying aesthetic appreciation.

  3. Non-invasive brain stimulation: enhancing motor and cognitive functions in healthy old subjects

    Directory of Open Access Journals (Sweden)

    Maximo Zimerman

    2010-12-01

    Full Text Available Healthy aging is accompanied by changes in cognitive and motor functions that result in impairment of activities of daily living. This process involves a number of modifications in the brain and is associated with metabolic, structural and physiological changes; some of these serving as adaptive responses to the functional declines. Up to date there are no universally accepted strategies to ameliorate declining functions in this population. An essential basis to develop such strategies is a better understanding of neuroplastic changes during healthy aging. In this context, non-invasive brain stimulation techniques, such as transcranial direct current or transcranial magnetic stimulation, provide an attractive option to modulate cortical neuronal assemblies, even with subsequent changes in neuroplasticity. Thus, in the present review we discuss the use of these techniques as a tool to study underlying cortical mechanisms during healthy aging and as an interventional strategy to enhance declining functions and learning abilities in aged subjects.

  4. Magneto-electric nano-particles for non-invasive brain stimulation.

    Directory of Open Access Journals (Sweden)

    Kun Yue

    Full Text Available This paper for the first time discusses a computational study of using magneto-electric (ME nanoparticles to artificially stimulate the neural activity deep in the brain. The new technology provides a unique way to couple electric signals in the neural network to the magnetic dipoles in the nanoparticles with the purpose to enable a non-invasive approach. Simulations of the effect of ME nanoparticles for non-invasively stimulating the brain of a patient with Parkinson's Disease to bring the pulsed sequences of the electric field to the levels comparable to those of healthy people show that the optimized values for the concentration of the 20-nm nanoparticles (with the magneto-electric (ME coefficient of 100 V cm(-1 Oe(-1 in the aqueous solution is 3 × 10(6 particles/cc, and the frequency of the externally applied 300-Oe magnetic field is 80 Hz.

  5. Brain functional connectivity in stimulant drug dependence and obsessive-compulsive disorder.

    Science.gov (United States)

    Meunier, David; Ersche, Karen D; Craig, Kevin J; Fornito, Alex; Merlo-Pich, Emilio; Fineberg, Naomi A; Shabbir, Shaila S; Robbins, Trevor W; Bullmore, Edward T

    2012-01-16

    There are reasons for thinking that obsessive-compulsive disorder (OCD) and drug dependence, although conventionally distinct diagnostic categories, might share important cognitive and neurobiological substrates. We tested this hypothesis directly by comparing brain functional connectivity measures between patients with OCD, stimulant dependent individuals (SDIs; many of whom were non-dependent users of other recreational drugs) and healthy volunteers. We measured functional connectivity between each possible pair of 506 brain regional functional MRI time series representing low frequency (0.03-0.06 Hz) spontaneous brain hemodynamics in healthy volunteers (N=18), patients with OCD (N=18) and SDIs (N=18). We used permutation tests to identify i) brain regions where strength of connectivity was significantly different in both patient groups compared to healthy volunteers; and ii) brain regions and connections which had significantly different functional connectivity between patient groups. We found that functional connectivity of right inferior and superior orbitofrontal cortex (OFC) was abnormally reduced in both disorders. Whether diagnosed as OCD or SDI, patients with higher scores on measures of compulsive symptom severity showed greater reductions of right orbitofrontal connectivity. Functional connections specifically between OFC and dorsal medial pre-motor and cingulate cortex were attenuated in both patient groups. However, patients with OCD demonstrated more severe and extensive reductions of functional connectivity compared to SDIs. OCD and stimulant dependence are not identical at the level of brain functional systems but they have some important abnormalities in common compared with healthy volunteers. Orbitofrontal connectivity may serve as a human brain systems biomarker for compulsivity across diagnostic categories.

  6. Long-term follow-up study on the safety of deep brain stimulation for treating Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Xi WU

    2015-10-01

    Full Text Available Objective To evaluate the safety of deep brain stimulation (DBS for treating Parkinson's disease (PD under long-term follow-up and modify the surgical procedure. Methods A total of 362 PD patients underwent DBS, and almost 613 electrodes were implanted into these patients. Both surgical and hardware-related complications of DBS were retrospectively analyzed. Results Perioperative complications included postoperative confusion or delirium in 21 cases (5.80%, intracranial hemorrhage in 4 cases (1.10%; 2 asymptomatic cortical microhemorrhage and 2 basal ganglia trajectory microhemorrhage, generalized tonic-clonic seizures (GTCS in 2 cases (0.55% , urinary tract infection in 4 cases (1.10% , pulmonary infection in 7 cases (1.93%, implantable pulse generator (IPG hematoma in 11 cases (3.04%, IPG seroma in 3 cases (0.83%. All these patients were cured. They were followed-up for 12-146 months (median 34 months. Hardware-related complications included infection of incisional wound and/or skin erosion (9 cases, 2.49% , extension wire fracture caused by IPG displacement (one case, 0.28% , IPG shifting to abdomen due to fixation wire fracture (one case, 0.28%, slightly migrated electrode due to fall (one case, 0.28%, and discomfort about occipital incision (one case, 0.28%. Conclusions The overall risk of both surgical and hardware-related adverse events of DBS for treating PD is acceptably low. DOI: 10.3969/j.issn.1672-6731.2015.10.005

  7. Globus Pallidus Interna Deep Brain Stimulation in a Patient with Medically Intractable Meige Syndrome

    Directory of Open Access Journals (Sweden)

    Dae-Woong Bae

    2014-10-01

    Full Text Available Medical therapies in patients with Meige syndrome, including botulinum toxin injection, have been limited because of incomplete response or adverse side effects. We evaluated a patient with Meige syndrome who was successfully treated with deep brain stimulation (DBS in the globus pallidus interna (GPi. This case report and other previous reports suggest that bilateral GPi DBS may be an effective treatment for medically refractory Meige syndrome, without significant adverse effects.

  8. Deep Brain Stimulation in Huntington’s Disease—Preliminary Evidence on Pathophysiology, Efficacy and Safety

    Directory of Open Access Journals (Sweden)

    Lars Wojtecki

    2016-08-01

    Full Text Available Huntington’s disease (HD is one of the most disabling degenerative movement disorders, as it not only affects the motor system but also leads to cognitive disabilities and psychiatric symptoms. Deep brain stimulation (DBS of the pallidum is a promising symptomatic treatment targeting the core motor symptom: chorea. This article gives an overview of preliminary evidence on pathophysiology, safety and efficacy of DBS in HD.

  9. Treatment of Pain and Autonomic Dysreflexia in Spinal Cord Injury with Deep Brain Stimulation

    Science.gov (United States)

    2015-10-01

    outcome and the incidence of insertional effect. Pain . 125, 188-96. Heinricher, M.M., et al., 2009. Descending control of nociception : Specificity...T.R., Henderson, J., 2010. Intracranial neurostimulation for pain control: a review. Pain Physician. 13, 157-65. Lovick, T.A., 2008. Pro- nociceptive ...AWARD NUMBER: W81XWH-12-1-0559 TITLE: Treatment of Pain and Autonomic Dysreflexia in Spinal Cord Injury with Deep Brain Stimulation PRINCIPAL

  10. The Morphological and Molecular Changes of Brain Cells Exposed to Direct Current Electric Field Stimulation

    OpenAIRE

    Pelletier, Simon J.; Lagacé, Marie; St-Amour, Isabelle; Arsenault, Dany; Cisbani, Giulia; Chabrat, Audrey; Fecteau, Shirley; Lévesque, Martin; Cicchetti, Francesca

    2015-01-01

    Background: The application of low-intensity direct current electric fields has been experimentally used in the clinic to treat a number of brain disorders, predominantly using transcranial direct current stimulation approaches. However, the cellular and molecular changes induced by such treatment remain largely unknown. Methods: Here, we tested various intensities of direct current electric fields (0, 25, 50, and 100V/m) in a well-controlled in vitro environment in order to investigate the r...

  11. Quantitative analysis of gait and balance response to deep brain stimulation in Parkinson's disease

    OpenAIRE

    Mera, Thomas O.; Filipkowski, Danielle E.; Riley, David E.; Whitney, Christina M.; Walter, Benjamin L.; Gunzler, Steven A; Giuffrida, Joseph P

    2012-01-01

    Gait and balance disturbances in Parkinson’s disease (PD) can be debilitating and may lead to increased fall risk. Deep brain stimulation (DBS) is a treatment option once therapeutic benefits from medication are limited due to motor fluctuations and dyskinesia. Optimizing DBS parameters for gait and balance can be significantly more challenging than for other PD motor symptoms. Furthermore, inter-rater reliability of the standard clinical PD assessment scale, Unified Parkinson’s Disease Ratin...

  12. Rapid Modulation of Distributed Brain Activity by Transcranial Magnetic Stimulation of Human Motor Cortex

    OpenAIRE

    Lucy Lee; Hartwig Siebner; Sven Bestmann

    2006-01-01

    This paper reviews the effects of single and repetitive transcranial magnetic stimuli (rTMS) delivered to one cortical area and measured across distributed brain regions using electrophysiological measures (e.g. motor thresholds, motor evoked potentials, paired-pulse stimulation), functional neuroimaging (including EEG, PET and fMRI) and behavioural measures. Discussion is restricted to changes in excitability in the primary motor cortex and behaviour during motor tasks following transcranial...

  13. Reversing cognitive-motor impairments in Parkinson's disease patients using a computational modelling approach to deep brain stimulation programming.

    Science.gov (United States)

    Frankemolle, Anneke M M; Wu, Jennifer; Noecker, Angela M; Voelcker-Rehage, Claudia; Ho, Jason C; Vitek, Jerrold L; McIntyre, Cameron C; Alberts, Jay L

    2010-03-01

    Deep brain stimulation in the subthalamic nucleus is an effective and safe surgical procedure that has been shown to reduce the motor dysfunction of patients with advanced Parkinson's disease. Bilateral subthalamic nucleus deep brain stimulation, however, has been associated with declines in cognitive and cognitive-motor functioning. It has been hypothesized that spread of current to nonmotor areas of the subthalamic nucleus may be responsible for declines in cognitive and cognitive-motor functioning. The aim of this study was to assess the cognitive-motor performance in advanced Parkinson's disease patients with subthalamic nucleus deep brain stimulation parameters determined clinically (Clinical) to settings derived from a patient-specific computational model (Model). Data were collected from 10 patients with advanced Parkinson's disease bilaterally implanted with subthalamic nucleus deep brain stimulation systems. These patients were assessed off medication and under three deep brain stimulation conditions: Off, Clinical or Model based stimulation. Clinical stimulation parameters had been determined based on clinical evaluations and were stable for at least 6 months prior to study participation. Model-based parameters were selected to minimize the spread of current to nonmotor portions of the subthalamic nucleus using Cicerone Deep Brain Stimulation software. For each stimulation condition, participants performed a working memory (n-back task) and motor task (force tracking) under single- and dual-task settings. During the dual-task, participants performed the n-back and force-tracking tasks simultaneously. Clinical and Model parameters were equally effective in improving the Unified Parkinson's disease Rating Scale III scores relative to Off deep brain stimulation scores. Single-task working memory declines, in the 2-back condition, were significantly less under Model compared with Clinical deep brain stimulation settings. Under dual-task conditions, force

  14. Localized stimulation of the human brain and spinal cord by a pair of opposing pulsed magnetic fields

    Science.gov (United States)

    Ueno, S.; Matsuda, T.; Hiwaki, O.

    1990-05-01

    A method of localized stimulation of the human brain and spinal cord is proposed. The basic idea is to concentrate induced eddy currents locally in the vicinity of a target by a pair of opposing pulsed magnetic fields. A pair of coils are positioned outside the head in the opposite directions around a target. The eddy currents induced at the target are expected to flow together, which results in an increased current flow at the target. A figure-eight coil is designed, and the magnetic brain stimulation is carried out using ourselves as volunteers. The results show that the selective stimulation of the brain is realized with a 5-mm resolution. The functional mapping of the human motor cortex related to the hand, arm, and foot areas is obtained. It is also obtained that an optimum direction of stimulating currents for neural excitation exists in each functional area in the cortex. Magnetic stimulation of the spinal cord is carried out by the same method as used in the brain stimulation. Rabbits are used in the experiments. A figure-eight coil is positioned on the surface of the spine. Shifting the stimulating points on the spine, electromyographic (EMG) signals are recorded from limb muscles. The EMG signals are clearly responding to the stimulation at a segment which innervates limb muscles, whereas no EMG signals are obtained by stimulation of segments higher than the critical segment. It is also obtained that the amplitude of the EMG signals varies with the direction of stimulating currents.

  15. Spinal Anesthesia and Minimal Invasive Laminotomy for Paddle Electrode Placement in Spinal Cord Stimulation: Technical Report and Clinical Results at Long-Term Followup

    Directory of Open Access Journals (Sweden)

    S. Sarubbo

    2012-01-01

    Full Text Available Object. We arranged a mini-invasive surgical approach for implantation of paddle electrodes for SCS under spinal anesthesia obtaining the best paddle electrode placement and minimizing patients’ discomfort. We describe our technique supported by neurophysiological intraoperative monitoring and clinical results. Methods. 16 patients, affected by neuropathic pain underwent the implantation of paddle electrodes for spinal cord stimulation in lateral decubitus under spinal anesthesia. The paddle was introduced after flavectomy and each patient confirmed the correct distribution of paresthesias induced by intraoperative test stimulation. VAS and patients’ satisfaction rate were recorded during the followup and compared to preoperative values. Results. No patients reported discomfort during the procedure. In all cases, paresthesias coverage of the total painful region was achieved, allowing the best final electrode positioning. At the last followup (mean 36.7 months, 87.5% of the implanted patients had a good rate of satisfaction with a mean VAS score improvement of 70.5%. Conclusions. Spinal cord stimulation under spinal anesthesia allows an optimal positioning of the paddle electrodes without any discomfort for patients or neurosurgeons. The best intraoperative positioning allows a better postoperative control of pain, avoiding the risk of blind placements of the paddle or further surgery for their replacement.

  16. [A Case of Left Vertebral Artery Aneurysm Showing Evoked Potentials on Bilateral Electrode by the Left Vagus Nerve Stimulation to Electromyographic Tracheal Tube].

    Science.gov (United States)

    Kadoya, Tatsuo; Uehara, Hirofumi; Yamamoto, Toshinori; Shiraishi, Munehiro; Kinoshita, Yuki; Joyashiki, Takeshi; Enokida, Kengo

    2016-02-01

    Previously, we reported a case of brainstem cavernous hemangioma showing false positive responses to electromyographic tracheal tube (EMG tube). We concluded that the cause was spontaneous respiration accompanied by vocal cord movement. We report a case of left vertebral artery aneurysm showing evoked potentials on bilateral electrodes by the left vagus nerve stimulation to EMG tube. An 82-year-old woman underwent clipping of a left unruptured vertebral artery-posterior inferior cerebellar artery aneurysm. General anesthesia was induced with remifentanil, propofol and suxamethonium, and was maintained with oxygen, air, remifentanil and propofol. We monitored somatosensory evoked potentials, motor evoked potentials, and electromyogram of the vocal cord. When the manipulation reached brainstem and the instrument touched the left vagus nerve, evoked potentials appeared on bilateral electrodes. EMG tube is equipped with two electrodes on both sides. We concluded that the left vagus nerve stimulation generated evoked potentials of the left laryngeal muscles, and they were simultaneously detected as potential difference between two electrodes on both sides. EMG tube is used to identify the vagus nerve. However, it is necessary to bear in mind that each vagus nerve stimulation inevitably generates evoked potentials on bilateral electrodes.

  17. Light Stimulation Properties to Influence Brain Activity: A Brain-CoMputer Interface application

    NARCIS (Netherlands)

    Bieger, J.; Garcia Molina, G.

    2010-01-01

    Brain-Computer Interfaces (BCIs) enable people to control appliances without involving the normal output pathways of peripheral nervesand muscles. A particularly promising type of BCI is based on the Steady-State Visual Evoked Potential (SSVEP). Users can selectcommands by focusing their attention o

  18. Image-guided preoperative prediction of pyramidal tract side effect in deep brain stimulation: proof of concept and application to the pyramidal tract side effect induced by pallidal stimulation.

    Science.gov (United States)

    Baumgarten, Clement; Zhao, Yulong; Sauleau, Paul; Malrain, Cecile; Jannin, Pierre; Haegelen, Claire

    2016-04-01

    Deep brain stimulation of the medial globus pallidus (GPm) is a surgical procedure for treating patients suffering from Parkinson's disease. Its therapeutic effect may be limited by the presence of pyramidal tract side effect (PTSE). PTSE is a contraction time-locked to the stimulation when the current spreading reaches the motor fibers of the pyramidal tract within the internal capsule. The objective of the study was to propose a preoperative predictive model of PTSE. A machine learning-based method called PyMAN (PTSE model based on artificial neural network) accounting for the current used in stimulation, the three-dimensional electrode coordinates and the angle of the trajectory, was designed to predict the occurrence of PTSE. Ten patients implanted in the GPm have been tested by a clinician to create a labeled dataset of the stimulation parameters that trigger PTSE. The kappa index value between the data predicted by PyMAN and the labeled data was 0.78. Further evaluation studies are desirable to confirm whether PyMAN could be a reliable tool for assisting the surgeon to prevent PTSE during the preoperative planning.

  19. Non-invasive brain stimulation: an interventional tool for enhancing behavioral training after stroke

    Directory of Open Access Journals (Sweden)

    Maximilian Jonas Wessel

    2015-05-01

    Full Text Available Stroke is the leading cause of disability among adults. Motor deficit is the most common impairment after stroke. Especially, deficits in fine motor skills impair numerous activities of daily life. Re-acquisition of motor skills resulting in improved or more accurate motor performance is paramount to regain function, and is the basis of behavioral motor therapy after stroke. Within the past years, there has been a rapid technological and methodological development in neuroimaging leading to a significant progress in the understanding of the neural substrates that underlie motor skill acquisition and functional recovery in stroke patients. Based on this and the development of novel non-invasive brain stimulation techniques, new adjuvant interventional approaches that augment the response to behavioral training have been proposed. Transcranial direct current (tDCS, transcranial magnetic (TMS and paired associative (PAS stimulation are noninvasive brain stimulation techniques that can modulate cortical excitability, neuronal plasticity and interact with learning and memory in both healthy individuals and stroke patients. These techniques can enhance the effect of practice and facilitate the retention of tasks that mimic daily life activities. The purpose of the present review is to provide a comprehensive overview of neuroplastic phenomena in the motor system during learning of a motor skill, recovery after brain injury, and of interventional strategies to enhance the beneficial effects of customarily used neurorehabilitation after stroke.

  20. Effects of scanner acoustic noise on intrinsic brain activity during auditory stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yakunina, Natalia [Kangwon National University, Institute of Medical Science, School of Medicine, Chuncheon (Korea, Republic of); Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kang, Eun Kyoung [Kangwon National University Hospital, Department of Rehabilitation Medicine, Chuncheon (Korea, Republic of); Kim, Tae Su [Kangwon National University Hospital, Department of Otolaryngology, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of); Min, Ji-Hoon [University of Michigan, Department of Biopsychology, Cognition, and Neuroscience, Ann Arbor, MI (United States); Kim, Sam Soo [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Radiology, Chuncheon (Korea, Republic of); Nam, Eui-Cheol [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of)

    2015-10-15

    Although the effects of scanner background noise (SBN) during functional magnetic resonance imaging (fMRI) have been extensively investigated for the brain regions involved in auditory processing, its impact on other types of intrinsic brain activity has largely been neglected. The present study evaluated the influence of SBN on a number of intrinsic connectivity networks (ICNs) during auditory stimulation by comparing the results obtained using sparse temporal acquisition (STA) with those using continuous acquisition (CA). Fourteen healthy subjects were presented with classical music pieces in a block paradigm during two sessions of STA and CA. A volume-matched CA dataset (CAm) was generated by subsampling the CA dataset to temporally match it with the STA data. Independent component analysis was performed on the concatenated STA-CAm datasets, and voxel data, time courses, power spectra, and functional connectivity were compared. The ICA revealed 19 ICNs; the auditory, default mode, salience, and frontoparietal networks showed greater activity in the STA. The spectral peaks in 17 networks corresponded to the stimulation cycles in the STA, while only five networks displayed this correspondence in the CA. The dorsal default mode and salience networks exhibited stronger correlations with the stimulus waveform in the STA. SBN appeared to influence not only the areas of auditory response but also the majority of other ICNs, including attention and sensory networks. Therefore, SBN should be regarded as a serious nuisance factor during fMRI studies investigating intrinsic brain activity under external stimulation or task loads. (orig.)

  1. Restoring Conscious Arousal During Focal Limbic Seizures with Deep Brain Stimulation.

    Science.gov (United States)

    Kundishora, Adam J; Gummadavelli, Abhijeet; Ma, Chanthia; Liu, Mengran; McCafferty, Cian; Schiff, Nicholas D; Willie, Jon T; Gross, Robert E; Gerrard, Jason; Blumenfeld, Hal

    2016-03-03

    Impaired consciousness occurs suddenly and unpredictably in people with epilepsy, markedly worsening quality of life and increasing risk of mortality. Focal seizures with impaired consciousness are the most common form of epilepsy and are refractory to all current medical and surgical therapies in about one-sixth of cases. Restoring consciousness during and following seizures would be potentially transformative for these individuals. Here, we investigate deep brain stimulation to improve level of conscious arousal in a rat model of focal limbic seizures. We found that dual-site stimulation of the central lateral nucleus of the intralaminar thalamus (CL) and the pontine nucleus oralis (PnO) bilaterally during focal limbic seizures restored normal-appearing cortical electrophysiology and markedly improved behavioral arousal. In contrast, single-site bilateral stimulation of CL or PnO alone was insufficient to achieve the same result. These findings support the "network inhibition hypothesis" that focal limbic seizures impair consciousness through widespread inhibition of subcortical arousal. Driving subcortical arousal function would be a novel therapeutic approach to some forms of refractory epilepsy and may be compatible with devices already in use for responsive neurostimulation. Multisite deep brain stimulation of subcortical arousal structures may benefit not only patients with epilepsy but also those with other disorders of consciousness.

  2. Induction of neuroplasticity and recovery in post-stroke aphasia by non-invasive brain stimulation

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    Priyanka eShah

    2013-12-01

    Full Text Available Stroke victims tend to prioritize speaking, writing and walking as the three most important rehabilitation goals. Of note is that two of these goals involve communication. This underscores the significance of developing successful approaches to aphasia treatment for the several hundred thousand new aphasia patients each year and over 1 million stroke survivors with chronic aphasia in the U.S. alone. After several years of growth as a research tool, noninvasive brain stimulation (NBS is gradually entering the arena of clinical aphasiology. In this review, we first examine the current state of knowledge of post-stroke language recovery including the contributions from the dominant and non-dominant hemispheres. Next, we briefly discuss the methods and the physiologic basis of the use of inhibitory and excitatory repetitive transcranial magnetic stimulation (rTMS and transcranial direct current stimulation (tDCS as research tools in patients who experience post-stroke aphasia. Finally, we provide a critical review of the most influential evidence behind the potential use of these two brain stimulation methods as clinical rehabilitative tools.

  3. Fornix deep brain stimulation induced long-term spatial memory independent of hippocampal neurogenesis.

    Science.gov (United States)

    Hescham, Sarah; Temel, Yasin; Schipper, Sandra; Lagiere, Mélanie; Schönfeld, Lisa-Maria; Blokland, Arjan; Jahanshahi, Ali

    2017-03-01

    Deep brain stimulation (DBS) is an established symptomatic treatment modality for movement disorders and constitutes an emerging therapeutic approach for the treatment of memory impairment. In line with this, fornix DBS has shown to ameliorate cognitive decline associated with dementia. Nonetheless, mechanisms mediating clinical effects in demented patients or patients with other neurological disorders are largely unknown. There is evidence that DBS is able to modulate neurophysiological activity in targeted brain regions. We therefore hypothesized that DBS might be able to influence cognitive function via activity-dependent regulation of hippocampal neurogenesis. Using stimulation parameters, which were validated to restore memory loss in a previous behavioral study, we here assessed long-term effects of fornix DBS. To do so, we injected the thymidine analog, 5-bromo-2'-deoxyuridine (BrdU), after DBS and perfused the animals 6.5 weeks later. A week prior to perfusion, memory performance was assessed in the water maze. We found that acute stimulation of the fornix improved spatial memory performance in the water maze when the probe trial was performed 1 h after the last training session. However, no evidence for stimulation-induced neurogenesis was found in fornix DBS rats when compared to sham. Our results suggest that fornix DBS improves memory functions independent of hippocampal neurogenesis, possibly through other mechanisms such as synaptic plasticity and acute neurotransmitter release.

  4. Predicting the Probability of Abnormal Stimulated Growth Hormone Response in Children After Radiotherapy for Brain Tumors

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    Hua Chiaho, E-mail: Chia-Ho.Hua@stjude.org [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu Shengjie [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Chemaitilly, Wassim [Division of Endocrinology, Department of Pediatric Medicine, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Lukose, Renin C.; Merchant, Thomas E. [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2012-11-15

    Purpose: To develop a mathematical model utilizing more readily available measures than stimulation tests that identifies brain tumor survivors with high likelihood of abnormal growth hormone secretion after radiotherapy (RT), to avoid late recognition and a consequent delay in growth hormone replacement therapy. Methods and Materials: We analyzed 191 prospectively collected post-RT evaluations of peak growth hormone level (arginine tolerance/levodopa stimulation test), serum insulin-like growth factor 1 (IGF-1), IGF-binding protein 3, height, weight, growth velocity, and body mass index in 106 children and adolescents treated for ependymoma (n = 72), low-grade glioma (n = 28) or craniopharyngioma (n = 6), who had normal growth hormone levels before RT. Normal level in this study was defined as the peak growth hormone response to the stimulation test {>=}7 ng/mL. Results: Independent predictor variables identified by multivariate logistic regression with high statistical significance (p < 0.0001) included IGF-1 z score, weight z score, and hypothalamic dose. The developed predictive model demonstrated a strong discriminatory power with an area under the receiver operating characteristic curve of 0.883. At a potential cutoff point of probability of 0.3 the sensitivity was 80% and specificity 78%. Conclusions: Without unpleasant and expensive frequent stimulation tests, our model provides a quantitative approach to closely follow the growth hormone secretory capacity of brain tumor survivors. It allows identification of high-risk children for subsequent confirmatory tests and in-depth workup for diagnosis of growth hormone deficiency.

  5. Secondary hyperalgesia phenotypes exhibit differences in brain activation during noxious stimulation

    DEFF Research Database (Denmark)

    Asghar, Mohammad Sohail; Pereira, Manuel Pedro; Werner, Mads Utke;

    2015-01-01

    . To study differences in the propensity to develop central sensitization we examined differences in brain activity and anatomy according to individual phenotypical expression of secondary hyperalgesia by magnetic resonance imaging. Forty healthy volunteers received a first-degree burn-injury (47 °C, 7 min...... hyperalgesia areas after burn-injury. In addition, T1-weighted images were used to measure differences in gray-matter density in cortical and subcortical regions of the brain. We found significant differences in neuronal activity between high- and low-sensitization responders at baseline (before application...... in high-sensitization responders in comparison to low-sensitization responders. These findings suggest that brain-structure and neuronal activation to noxious stimulation differs according to secondary hyperalgesia phenotype. This indicates differences in central sensitization according to phenotype...

  6. Restoring cognitive functions using non-invasive brain stimulation techniques in patients with cerebellar disorders

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    Paul A Pope

    2014-04-01

    Full Text Available Numerous studies have highlighted the possibility of modulating the excitability of cerebro-cerebellar circuits bi-directionally using transcranial electrical brain stimulation, in a manner akin to that observed using magnetic stimulation protocols. It has been proposed that cerebellar stimulation activates Purkinje cells in the cerebellar cortex, leading to inhibition of the dentate nucleus, which exerts a tonic facilitatory drive onto motor and cognitive regions of cortex through a synaptic relay in the ventral-lateral thalamus. Some cerebellar deficits present with cognitive impairments if damage to non-motor regions of the cerebellum disrupts the coupling with cerebral cortical areas for thinking and reasoning. Indeed, white matter changes in the dentato-rubral tract correlate with cognitive assessments in patients with Friedreich ataxia, suggesting that this pathway is one component of the anatomical substrate supporting a cerebellar contribution to cognition. An understanding of the physiology of the cerebro-cerebellar pathway previously helped us to constrain our interpretation of results from two recent studies in which we showed cognitive enhancements in healthy participants during tests of arithmetic after electrical stimulation of the cerebellum, but only when task demands were high. Others studies have also shown how excitation of the prefrontal cortex can enhance performance in a variety of working memory tasks. Thus, future efforts might be guided towards neuro-enhancement in certain patient populations, using what is commonly termed 'non-invasive brain stimulation' as a cognitive rehabilitation tool to modulate cerebro-cerebellar circuits, or for stimulation over the cerebral cortex to compensate for decreased cerebellar drive to this region. This article will address these possibilities with a review of the relevant literature covering ataxias and cerebellar cognitive affective disorders, which are characterized by thalamo

  7. Restoring cognitive functions using non-invasive brain stimulation techniques in patients with cerebellar disorders.

    Science.gov (United States)

    Pope, Paul A; Miall, R Chris

    2014-01-01

    Numerous studies have highlighted the possibility of modulating the excitability of cerebro-cerebellar circuits bi-directionally using transcranial electrical brain stimulation, in a manner akin to that observed using magnetic stimulation protocols. It has been proposed that cerebellar stimulation activates Purkinje cells in the cerebellar cortex, leading to inhibition of the dentate nucleus, which exerts a tonic facilitatory drive onto motor and cognitive regions of cortex through a synaptic relay in the ventral-lateral thalamus. Some cerebellar deficits present with cognitive impairments if damage to non-motor regions of the cerebellum disrupts the coupling with cerebral cortical areas for thinking and reasoning. Indeed, white matter changes in the dentato-rubral tract correlate with cognitive assessments in patients with Friedreich ataxia, suggesting that this pathway is one component of the anatomical substrate supporting a cerebellar contribution to cognition. An understanding of the physiology of the cerebro-cerebellar pathway previously helped us to constrain our interpretation of results from two recent studies in which we showed cognitive enhancements in healthy participants during tests of arithmetic after electrical stimulation of the cerebellum, but only when task demands were high. Others studies have also shown how excitation of the prefrontal cortex can enhance performance in a variety of working memory tasks. Thus, future efforts might be guided toward neuro-enhancement in certain patient populations, using what is commonly termed "non-invasive brain stimulation" as a cognitive rehabilitation tool to modulate cerebro-cerebellar circuits, or for stimulation over the cerebral cortex to compensate for decreased cerebellar drive to this region. This article will address these possibilities with a review of the relevant literature covering ataxias and cerebellar cognitive affective disorders, which are characterized by thalamo-cortical disturbances.

  8. Modeling the effects of noninvasive transcranial brain stimulation at the biophysical, network, and cognitive level.

    Science.gov (United States)

    Hartwigsen, Gesa; Bergmann, Til Ole; Herz, Damian Marc; Angstmann, Steffen; Karabanov, Anke; Raffin, Estelle; Thielscher, Axel; Siebner, Hartwig Roman

    2015-01-01

    Noninvasive transcranial brain stimulation (NTBS) is widely used to elucidate the contribution of different brain regions to various cognitive functions. Here we present three modeling approaches that are informed by functional or structural brain mapping or behavior profiling and discuss how these approaches advance the scientific potential of NTBS as an interventional tool in cognitive neuroscience. (i) Leveraging the anatomical information provided by structural imaging, the electric field distribution in the brain can be modeled and simulated. Biophysical modeling approaches generate testable predictions regarding the impact of interindividual variations in cortical anatomy on the injected electric fields or the influence of the orientation of current flow on the physiological stimulation effects. (ii) Functional brain mapping of the spatiotemporal neural dynamics during cognitive tasks can be used to construct causal network models. These models can identify spatiotemporal changes in effective connectivity during distinct cognitive states and allow for examining how effective connectivity is shaped by NTBS. (iii) Modeling the NTBS effects based on neuroimaging can be complemented by behavior-based cognitive models that exploit variations in task performance. For instance, NTBS-induced changes in response speed and accuracy can be explicitly modeled in a cognitive framework accounting for the speed-accuracy trade-off. This enables to dissociate between behavioral NTBS effects that emerge in the context of rapid automatic responses or in the context of slow deliberate responses. We argue that these complementary modeling approaches facilitate the use of NTBS as a means of dissecting the causal architecture of cognitive systems of the human brain.

  9. Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson's disease.

    Science.gov (United States)

    Fregni, Felipe; Boggio, Paulo S; Santos, Marcelo C; Lima, Moises; Vieira, Adriana L; Rigonatti, Sergio P; Silva, M Teresa A; Barbosa, Egberto R; Nitsche, Michael A; Pascual-Leone, Alvaro

    2006-10-01

    Electrical stimulation of deep brain structures, such as globus pallidus and subthalamic nucleus, is widely accepted as a therapeutic tool for patients with Parkinson's disease (PD). Cortical stimulation either with epidural implanted electrodes or repetitive transcranial magnetic stimulation can be associated with motor function enhancement in PD. We aimed to study the effects of another noninvasive technique of cortical brain stimulation, transcranial direct current stimulation (tDCS), on motor function and motor-evoked potential (MEP) characteristics of PD patients. We tested tDCS using different electrode montages [anodal stimulation of primary motor cortex (M1), cathodal stimulation of M1, anodal stimulation of dorsolateral prefrontal cortex (DLPFC), and sham-stimulation] and evaluated the effects on motor function--as indexed by Unified Parkinson's Disease Rating Scale (UPDRS), simple reaction time (sRT) and Purdue Pegboard test--and on corticospinal motor excitability (MEP characteristics). All experiments were performed in a double-blinded manner. Anodal stimulation of M1 was associated with a significant improvement of motor function compared to sham-stimulation in the UPDRS (P stimulation of M1 or anodal stimulation of DLPFC. Furthermore, whereas anodal stimulation of M1 significantly increased MEP amplitude and area, cathodal stimulation of M1 significantly decreased them. There was a trend toward a significant correlation between motor function improvement after M1 anodal-tDCS and MEP area increase. These results confirm and extend the notion that cortical brain stimulation might improve motor function in patients with PD.

  10. To what extent can dry and water-based EEG electrodes replace conductive gel ones?: A Steady State Visual Evoked Potential Brain-Computer Interface Case Study

    NARCIS (Netherlands)

    Mihajlovic, V.; Garcia Molina, G.; Peuscher, J

    2011-01-01

    Recent technological advances in the field of skin electrodes and on-body sensors indicate a possibility of having an alternative to the traditionally used conductive gel electrodes for measuring electrical signals of the brain (electroencephalogram, EEG). This paper evaluates whether water-based an

  11. Toward the restoration of hand use to a paralyzed monkey: brain-controlled functional electrical stimulation of forearm muscles.

    Directory of Open Access Journals (Sweden)

    Eric A Pohlmeyer

    Full Text Available Loss of hand use is considered by many spinal cord injury survivors to be the most devastating consequence of their injury. Functional electrical stimulation (FES of forearm and hand muscles has been used to provide basic, voluntary hand grasp to hundreds of human patients. Current approaches typically grade pre-programmed patterns of muscle activation using simple control signals, such as those derived from residual movement or muscle activity. However, the use of such fixed stimulation patterns limits hand function to the few tasks programmed into the controller. In contrast, we are developing a system that uses neural signals recorded from a multi-electrode array implanted in the motor cortex; this system has the potential to provide independent control of multiple muscles over a broad range of functional tasks. Two monkeys were able to use this cortically controlled FES system to control the contraction of four forearm muscles despite temporary limb paralysis. The amount of wrist force the monkeys were able to produce in a one-dimensional force tracking task was significantly increased. Furthermore, the monkeys were able to control the magnitude and time course of the force with sufficient accuracy to track visually displayed force targets at speeds reduced by only one-third to one-half of normal. Although these results were achieved by controlling only four muscles, there is no fundamental reason why the same methods could not be scaled up to control a larger number of muscles. We believe these results provide an important proof of concept that brain-controlled FES prostheses could ultimately be of great benefit to paralyzed patients with injuries in the mid-cervical spinal cord.

  12. Subthalamic nucleus deep brain stimulation does not improve visuo-motor impairment in Parkinson's disease.

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    Simon D Israeli-Korn

    Full Text Available OBJECTIVE: To evaluate how bilateral subthalamic nucleus deep brain stimulation (STN-DBS affects visuo-motor coordination (VMC in patients with Parkinson's disease (PD. BACKGROUND: VMC involves multi-sensory integration, motor planning, executive function and attention. VMC deficits are well-described in PD. STN-DBS conveys marked motor benefit in PD, but pyscho-cognitive complications are recognized and the effect on VMC is not known. METHODS: Thirteen PD patients with bilateral STN-DBS underwent neurological, cognitive, and mood assessment before VMC testing with optimal DBS stimulation parameters ('on-stimulation' and then, on the same day without any medication changes, after DBS silencing and establishing motor function deterioration ('off-stimulation'. Twelve age-matched healthy controls performed 2 successive VMC testing sessions, with a break of similar duration to that of the PD group. The computer cursor was controlled with a dome-shaped 'mouse' hidden from view that minimized tremor effects. Movement duration, hand velocity, tracking continuity, directional control variables, and feedback utilization variables were measured. MANOVA was performed on (1 clinically measured motor function, (2 VMC performance and (3 mood and attention, looking for main and interaction effects of: (1 group (controls/PD, (2 test-order (controls: first/second, PD: on-stimulation/off-stimulation, (3 path (sine/square/circle and (4 hand (dominant/non-dominant. RESULTS: Unified PD Rating Scale (UPDRS Part III worsened off-stimulation versus on-stimulation (mean: 42.3 versus 21.6, p = 0.02, as did finger tapping (p = 0.02, posture-gait (p = 0.01, upper limb function (p<0.001 and backwards digit span (p = 0.02. Stimulation state did not affect mood. PD patients performed worse in non-velocity related VMC variables than controls (F(5,18 = 8.5, p<0.001. In the control group there were significant main effects of hand (dominant/non-dominant, path

  13. EDITORIAL: Deep brain stimulation, deontology and duty: the moral obligation of non-abandonment at the neural interface Deep brain stimulation, deontology and duty: the moral obligation of non-abandonment at the neural interface

    Science.gov (United States)

    Fins, Joseph J.; MD; FACP

    2009-10-01

    At the height of the psychosurgery debate the editors of The Lancet referenced the popular hesitancy to intervene surgically with the workings of the brain. They wrote that to do so `carries a peculiar penumbra of sacrilege' [1, 2]. Penumbra of sacrilege is a memorable, even strange phrase. It is one worth unpacking as we embark on an era which will see ever more border crossings at the blood-brain barrier. By invoking popular beliefs about a penumbra of sacrilege, the editors were suggesting that psychosurgery represented a gray zone in the shadows, a desecration or violation of a sacred space, the seat of the soul, the self. And as such, they were reflecting a cultural hesitancy, a lay reluctance to pursue this work. Fortunately for those with intractable neuropsychiatric disorders, neuromodulation has evolved beyond the primitive—and barbaric—sweep of the lobotomy, and with this advance, categorical resistance to this work has dissipated. And that is all to the good. But as the field progresses, and we implant more and more devices for therapeutic and investigational purposes, we must not let the placement of electrodes become too easy. It is a decision that should be made with full awareness of its implications for patients and families. Recently, I spoke to a friend who appeared to have early essential tremor. (Some non-essential aspects of this story have been changed to protect confidentiality.) He asked me, `Do you know anything about deep brain stimulation?' I indicated that I did. `Really?', he asked, seemingly unaware of my scholarly interest in the topic [3, 4, 5, 6] and involvement as a co-investigator in the use of deep brain stimulation in the minimally conscious state [7, 8, 9]. Satisfied that I might be a credible source for some free advice, he told me that his neurologist had sent him to a neurosurgeon to see about a stimulator. I asked him how disabling his condition was. As he competently drank a cup of soda, he told me it was a bit of a

  14. Electromagnetic interference of GSM mobile phones with the implantable deep brain stimulator, ITREL-III

    Directory of Open Access Journals (Sweden)

    Alesch François

    2003-05-01

    Full Text Available Abstract Background The purpose was to investigate mobile phone interference with implantable deep brain stimulators by means of 10 different 900 Mega Hertz (MHz and 10 different 1800 MHz GSM (Global System for Mobile Communications mobile phones. Methods All tests were performed in vitro using a phantom especially developed for testing with deep brain stimulators. The phantom was filled with liquid phantom materials simulating brain and muscle tissue. All examinations were carried out inside an anechoic chamber on two implants of the same type of deep brain stimulator: ITREL-III from Medtronic Inc., USA. Results Despite a maximum transmitted peak power of mobile phones of 1 Watt (W at 1800 MHz and 2 W at 900 MHz respectively, no influence on the ITREL-III was found. Neither the shape of the pulse form changed nor did single pulses fail. Tests with increased transmitted power using CW signals and broadband dipoles have shown that inhibition of the ITREL-III occurs at frequency dependent power levels which are below the emissions of GSM mobile phones. The ITREL-III is essentially more sensitive at 1800 MHz than at 900 MHz. Particularly the frequency range around 1500 MHz shows a very low interference threshold. Conclusion These investigations do not indicate a direct risk for ITREL-III patients using the tested GSM phones. Based on the interference levels found with CW signals, which are below the mobile phone emissions, we recommend similar precautions as for patients with cardiac pacemakers: 1. The phone should be used at the ear at the opposite side of the implant and 2. The patient should avoid carrying the phone close to the implant.

  15. Characterising the Analgesic Effect of Different Targets for Deep Brain Stimulation in Trigeminal Anaesthesia Dolorosa

    Science.gov (United States)

    Sims-Williams, Hugh P.; Javed, Shazia; Pickering, Anthony E.; Patel, Nikunj K.

    2016-01-01

    Background Several deep brain stimulation (DBS) targets have been explored for the alleviation of trigeminal anaesthesia dolorosa. We aimed to characterise the analgesia produced from the periaqueductal grey (PAG) and centromedian-parafascicular (CmPf) nucleus using a within-subject design. Method We report a case series of 3 subjects implanted with PAG and CmPf DBS systems for the treatment of anaesthesia dolorosa. At follow-up, testing of onset and offset times, magnitude, and thermal and mechanical sensitivity was performed. Results The mean pain score of the cohort was acutely reduced by 56% (p effective at different stimulation frequencies and were not antagonistic in effect. Conclusion The mechanisms by which stimulation at these two targets produces analgesia are likely to be different. Certain pain qualities may respond more favourably to specific targets. Knowledge of onset and offset times for the targets can guide optimisation of stimulation settings. The use of more than one stimulation target may be beneficial and should be considered in anaesthesia dolorosa patients. PMID:27322524

  16. Deep Brain Stimulation of the Pedunculopontine Tegmental Nucleus (PPN) Influences Visual Contrast Sensitivity in Human Observers

    Science.gov (United States)

    Strumpf, Hendrik; Noesselt, Toemme; Schoenfeld, Mircea Ariel; Voges, Jürgen; Panther, Patricia; Kaufmann, Joern; Heinze, Hans-Jochen; Hopf, Jens-Max

    2016-01-01

    The parapontine nucleus of the thalamus (PPN) is a neuromodulatory midbrain structure with widespread connectivity to cortical and subcortical motor structures, as well as the spinal cord. The PPN also projects to the thalamus, including visual relay nuclei like the LGN and the pulvinar. Moreover, there is intense connectivity with sensory structures of the tegmentum in particular with the superior colliculus (SC). Given the existence and abundance of projections to visual sensory structures, it is likely that activity in the PPN has some modulatory influence on visual sensory selection. Here we address this possibility by measuring the visual discrimination performance (luminance contrast thresholds) in a group of patients with Parkinson’s Disease (PD) treated with deep-brain stimulation (DBS) of the PPN to control gait and postural motor deficits. In each patient we measured the luminance-contrast threshold of being able to discriminate an orientation-target (Gabor-grating) as a function of stimulation frequency (high 60Hz, low 8/10, no stimulation). Thresholds were determined using a standard staircase-protocol that is based on parameter estimation by sequential testing (PEST). We observed that under low frequency stimulation thresholds increased relative to no and high frequency stimulation in five out of six patients, suggesting that DBS of the PPN has a frequency-dependent impact on visual selection processes at a rather elementary perceptual level. PMID:27167979

  17. Functional Magnetic Resonance Imaging of Electrical and Optogenetic Deep Brain Stimulation at the Rat Nucleus Accumbens

    Science.gov (United States)

    Albaugh, Daniel L.; Salzwedel, Andrew; van den Berge, Nathalie; Gao, Wei; Stuber, Garret D.; Shih, Yen-Yu Ian

    2016-09-01

    Deep brain stimulation of the nucleus accumbens (NAc-DBS) is an emerging therapy for diverse, refractory neuropsychiatric diseases. Although DBS therapy is broadly hypothesized to work through large-scale neural modulation, little is known regarding the neural circuits and networks affected by NAc-DBS. Using a healthy, sedated rat model of NAc-DBS, we employed both evoked- and functional connectivity (fc) MRI to examine the functional circuit and network changes achieved by electrical NAc stimulation. Optogenetic-fMRI experiments were also undertaken to evaluate the circuit modulation profile achieved by selective stimulation of NAc neurons. NAc-DBS directly modulated neural activity within prefrontal cortex and a large number of subcortical limbic areas (e.g., amygdala, lateral hypothalamus), and influenced functional connectivity among sensorimotor, executive, and limbic networks. The pattern and extent of circuit modulation measured by evoked-fMRI was relatively insensitive to DBS frequency. Optogenetic stimulation of NAc cell bodies induced a positive fMRI signal in the NAc, but no other detectable downstream responses, indicating that therapeutic NAc-DBS might exert its effect through antidromic stimulation. Our study provides a comprehensive mapping of circuit and network-level neuromodulation by NAc-DBS, which should facilitate our developing understanding of its therapeutic mechanisms of action.

  18. Functional Magnetic Resonance Imaging of Electrical and Optogenetic Deep Brain Stimulation at the Rat Nucleus Accumbens

    Science.gov (United States)

    Albaugh, Daniel L.; Salzwedel, Andrew; Van Den Berge, Nathalie; Gao, Wei; Stuber, Garret D.; Shih, Yen-Yu Ian

    2016-01-01

    Deep brain stimulation of the nucleus accumbens (NAc-DBS) is an emerging therapy for diverse, refractory neuropsychiatric diseases. Although DBS therapy is broadly hypothesized to work through large-scale neural modulation, little is known regarding the neural circuits and networks affected by NAc-DBS. Using a healthy, sedated rat model of NAc-DBS, we employed both evoked- and functional connectivity (fc) MRI to examine the functional circuit and network changes achieved by electrical NAc stimulation. Optogenetic-fMRI experiments were also undertaken to evaluate the circuit modulation profile achieved by selective stimulation of NAc neurons. NAc-DBS directly modulated neural activity within prefrontal cortex and a large number of subcortical limbic areas (e.g., amygdala, lateral hypothalamus), and influenced functional connectivity among sensorimotor, executive, and limbic networks. The pattern and extent of circuit modulation measured by evoked-fMRI was relatively insensitive to DBS frequency. Optogenetic stimulation of NAc cell bodies induced a positive fMRI signal in the NAc, but no other detectable downstream responses, indicating that therapeutic NAc-DBS might exert its effect through antidromic stimulation. Our study provides a comprehensive mapping of circuit and network-level neuromodulation by NAc-DBS, which should facilitate our developing understanding of its therapeutic mechanisms of action. PMID:27601003

  19. Deep brain stimulation of the globus pallidus internus or ventralis intermedius nucleus of thalamus for Holmes tremor.

    Science.gov (United States)

    Espinoza Martinez, Jairo Alberto; Arango, Gabriel J; Fonoff, Erich Talamoni; Reithmeier, Thomas; Escobar, Oscar Andrés; Furlanetti, Luciano; Alvarez Berastegui, G Rene; Fernandes da Silva, Fabio Eduardo; Contreras Lopez, William Omar

    2015-10-01

    Holmes tremor (HT) is a difficult-to-treat, very disabling symptomatic condition which characteristically appears weeks to years after a brain lesion. It features a unique combination of rest, action, and postural tremors. Pharmacotherapy is mostly not effective. Chronic deep brain stimulation (DBS) of ventralis intermedius nucleus (Vim) of thalamus has been described as being the best surgical approach in singular case series; various authors observe, however, cases with partial responses only; therefore, alternatives are still needed. We report ten patients with HT unresponsive to best medical therapy who underwent DBS in our center from March 2002 to June 2012. Based in our previous experience dealing with cases of unsatisfactory Vim intraoperative tremor control and in order to optimize surgical results, presurgical target planning included two Nuclei: Vim and posteroventral Globus pallidus internus (GPi) (Espinoza et al. 2010; Espinoza et al. Stereotact Funct Neurosurg 90(suppl 1):1-202, p 61, 2012). Definitive chosen target was decided after single-cell microelectrode recording, intraoperative test stimulation, thresholds for stimulation-induced adverse effects and best clinical response compared to baseline status. Fahn-Tolosa-Marin tremor rating scale (FTM-TRS) was used to evaluate outcome. The electrode was implanted in the nucleus with the best tremor suppression achievement; on the other hand, GPi DBS was initially decided if one of the following conditions was present: (a) If Vim nucleus anatomy was grossly altered; (b) when intraoperative tremor control was unsatisfactory despite Vim high-intensity stimulation; or (c) if unaffordable side effects or even tremor worsening occurred during intraoperative macrostimulation. Seven patients received definitive Gpi DBS implantation, while three patients received Vim DBS. In all observed cases, we observed an improvement on the TRS. In two cases where Vim thalamic anatomy was altered by the pathological insult

  20. Disruption in proprioception from long-term thalamic deep brain stimulation: A pilot study

    Directory of Open Access Journals (Sweden)

    Jennifer A Semrau

    2015-05-01

    Full Text Available Deep brain stimulation (DBS is an excellent treatment for tremor and is generally thought to be reversible by turning off stimulation. For tremor, DBS is implanted in the ventrointermedius (Vim nucleus of the thalamus, a region that relays proprioceptive information for movement sensation (kinaesthesia. Gait disturbances have been observed with bilateral Vim DBS, but the long-term effects on proprioceptive processing are unknown. We aimed to determine whether Vim DBS surgical implantation or stimulation leads to proprioceptive deficits in the upper limb. We assessed two groups of tremor subjects on measures of proprioception (kinaesthesia, position sense and motor function using a robotic exoskeleton. In the first group (Surgery, we tested patients before and after implantation of Vim DBS, but before DBS was turned on to determine if proprioceptive deficits were inherent to tremor or caused by DBS implantation. In the second group (Stim, we tested subjects with chronically implanted Vim DBS ON and OFF stimulation. Compared to controls, there were no proprioceptive deficits before or after DBS implantation in the Surgery group. Surprisingly, those that received chronic long-term stimulation (LT-stim, 3-10 years displayed significant proprioceptive deficits ON and OFF stimulation not present in subjects with chronic short-term stimulation (ST-stim, 0.5-2 years. LT-stim had significantly larger variability and reduced workspace area during the position sense assessment. During the kinesthetic assessment, LT-stim made significantly larger directional errors and consistently underestimated the speed of the robot, despite generating normal movement speeds during motor assessment. Chronic long-term Vim DBS may potentially disrupt proprioceptive processing, possibly inducing irreversible plasticity in the Vim nucleus and/or its network connections. Our findings in the upper limb may help explain some of the gait disturbances seen by others following Vim

  1. Disruption in proprioception from long-term thalamic deep brain stimulation: a pilot study.

    Science.gov (United States)

    Semrau, Jennifer A; Herter, Troy M; Kiss, Zelma H; Dukelow, Sean P

    2015-01-01

    Deep brain stimulation (DBS) is an excellent treatment for tremor and is generally thought to be reversible by turning off stimulation. For tremor, DBS is implanted in the ventrointermedius (Vim) nucleus of the thalamus, a region that relays proprioceptive information for movement sensation (kinaesthesia). Gait disturbances have been observed with bilateral Vim DBS, but the long-term effects on proprioceptive processing are unknown. We aimed to determine whether Vim DBS surgical implantation or stimulation leads to proprioceptive deficits in the upper limb. We assessed two groups of tremor subjects on measures of proprioception (kinaesthesia, position sense) and motor function using a robotic exoskeleton. In the first group (Surgery), we tested patients before and after implantation of Vim DBS, but before DBS was turned on to determine if proprioceptive deficits were inherent to tremor or caused by DBS implantation. In the second group (Stim), we tested subjects with chronically implanted Vim DBS ON and OFF stimulation. Compared to controls, there were no proprioceptive deficits before or after DBS implantation in the Surgery group. Surprisingly, those that received chronic long-term stimulation (LT-stim, 3-10 years) displayed significant proprioceptive deficits ON and OFF stimulation not present in subjects with chronic short-term stimulation (ST-stim, 0.5-2 years). LT-stim had significantly larger variability and reduced workspace area during the position sense assessment. During the kinesthetic assessment, LT-stim made significantly larger directional errors and consistently underestimated the speed of the robot, despite generating normal movement speeds during motor assessment. Chronic long-term Vim DBS may potentially disrupt proprioceptive processing, possibly inducing irreversible plasticity in the Vim nucleus and/or its network connections. Our findings in the upper limb may help explain some of the gait disturbances seen by others following Vim DBS.

  2. Transcranial magnetic stimulation of degenerating brain: a comparison of normal aging, Alzheimer's, Parkinson's and Huntington's disease.

    Science.gov (United States)

    Ljubisavljevic, M R; Ismail, F Y; Filipovic, S

    2013-07-01

    Although the brain's ability to change constantly in response to external and internal inputs is now well recognized the mechanisms behind it in normal aging and neurodegeneration are less well understood. To gain a better understanding, transcranial magnetic stimulation (TMS) has been used extensively to characterize non-invasively the cortical neurophysiology of the aging and degenerating brain. Furthermore, there has been a surge of studies examining whether repetitive TMS (rTMS) can be used to improve functional deficits in various conditions including normal aging, Alzheimer's and Parkinson's disease. The results of these studies in normal aging and neurodegeneration have emerged reasonably coherent in delineating the main pathology in spite of considerable technical limitations, omnipresent methodological variability, and extraordinary patient heterogeneity. Nevertheless, comparing and integrating what is known about TMS measurements of cortical excitability and plasticity in disorders that predominantly affect cortical brain structures with disorders that predominantly affect subcortical brain structures may provide better understanding of normal and abnormal brain aging fostering new. The present review provides a TMS perspective of changes in cortical neurophysiology and neurochemistry in normal aging and neurodegeneration by integrating what is revealed in individual TMS measurements of cortical excitability and plasticity in physiological aging, Alzheimer's, Parkinson's, and Huntington's, disease. The paper also reflects on current developments in utilizing TMS as a physiologic biomarker to discriminate physiologic aging from neurodegeneration and its potential as a method of therapeutic intervention.

  3. Rapid, label-free detection of brain tumors with stimulated Raman scattering microscopy

    Science.gov (United States)

    Ji, Minbiao; Orringer, Daniel A.; Freudiger, Christian W.; Ramkissoon, Shakti; Liu, Xiaohui; Lau, Darryl; Golby, Alexandra J.; Norton, Isaiah; Hayashi, Marika; Agar, Nathalie Y.R.; Young, Geoffrey S.; Spino, Cathie; Santagata, Sandro; Camelo-Piragua, Sandra; Ligon, Keith L.; Sagher, Oren; Xie, X. Sunney

    2013-01-01

    Surgery is an essential component in the treatment of brain tumors. However, delineating tumor from normal brain remains a major challenge. Here we describe the use of stimulated Raman scattering (SRS) microscopy for differentiating healthy human and mouse brain tissue from tumor-infiltrated brain based on histoarchitectural and biochemical differences. Unlike traditional histopathology, SRS is a label-free technique that can be rapidly performed in situ. SRS microscopy was able to differentiate tumor from non-neoplastic tissue in an infiltrative human glioblastoma xenograft mouse model based on their different Raman spectra. We further demonstrated a correlation between SRS and H&E microscopy for detection of glioma infiltration (κ=0.98). Finally, we applied SRS microscopy in vivo in mice during surgery to reveal tumor margins that were undetectable under standard operative conditions. By providing rapid intraoperative assessment of brain tissue, SRS microscopy may ultimately improve the safety and accuracy of surgeries where tumor boundaries are visually indistinct. PMID:24005159

  4. On the importance of electrode parameters for shaping electric field patterns generated by tDCS

    DEFF Research Database (Denmark)

    B. Saturnino, Guilherme; Antunes, André; Thielscher, Axel

    2015-01-01

    Transcranial direct current stimulation (tDCS) uses electrode pads placed on the head to deliver weak direct current to the brain and modulate neuronal excitability. The effects depend on the intensity and spatial distribution of the electric field. This in turn depends on the geometry and electric...... electrode modeling influences the calculated electric field in the brain. We take into account electrode shape, size, connector position and conductivities of different electrode materials (including saline solutions and electrode gels). These factors are systematically characterized to demonstrate...

  5. Simple models of stimulation of neurones in the brain by electric fields.

    Science.gov (United States)

    Iles, J F

    2005-01-01

    The excitation of pyramidal cells in the motor cortex, produced by electric fields generated by distant electrodes or by electromagnetic induction, has been modelled. Linear, steady-state models of myelinated axons capture most of the geometrical aspects of neurone activation in electric fields. Some non-linear features can be approximated. Models with a proximal sealed-end and distal infinite axon, or of finite length, are both serviceable. Surface anodal stimulation produces hyperpolarisation of the proximal axon (closest to the anode) and depolarisation in the distal axon. The point of maximum depolarisation can be influenced by the location of the cathode (greater separation of anode and cathode causes more distal depolarisation). Axon bends can produce very localised depolarisation. Cathodal stimulation may be less effective than anodal as a result of anodal block of conduction of action potentials in the distal axon. The latencies of responses to anodal stimulation, recorded in the distal axon, will decrease as the stimulus strength is increased and the point of action potential initiation moves distally node by node. Larger jumps in latency will be produced when the point of action potential initiation moves from one axon bend to another.

  6. Targeting neural endophenotypes of eating disorders with non-invasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Katharine A Dunlop

    2016-02-01

    Full Text Available The term eating disorders (ED encompasses a wide variety of disordered eating and compensatory behaviors, and so the term is associated with considerable clinical and phenotypic heterogeneity. This heterogeneity makes optimizing treatment techniques difficult. One class of treatments is non-invasive brain stimulation (NIBS. NIBS, including repetitive transcranial magnetic stimulation (rTMS and transcranial direct current stimulation (tDCS are accessible forms of neuromodulation that alter the cortical excitability of a target brain region. It is crucial for NIBS to be successful that the target is well selected for the patient population in question. Targets may best be selected by stepping back from conventional DSM-5 diagnostic criteria to identify neural substrates of more basic phenotypes, including behavior related rewards and punishment cognitive control, and social processes. These phenotypic dimensions have been recently laid out by the Research Domain Criteria (RDoC initiative. Consequently, this review is intended to identify potential dimensions as outlined by the RDoC and their underlying behavioral and neurobiological targets associated with ED as potential candidates for NIBS and review the available literature on rTMS and tDCS in ED. This review systematically reviews abnormal neural circuitry in ED within the RDoC framework, and also systematically reviews the available literature investigating NIBS as a treatment for ED.

  7. Studies of the neural mechanisms of deep brain stimulation in rodent models of Parkinson's disease.

    Science.gov (United States)

    Chang, Jing-Yu; Shi, Li-Hong; Luo, Fei; Zhang, Wang-Ming; Woodward, Donald J

    2008-01-01

    Several rodent models of deep brain stimulation (DBS) have been developed in recent years. Electrophysiological and neurochemical studies have been performed to examine the mechanisms underlying the effects of DBS. In vitro studies have provided deep insights into the role of ion channels in response to brain stimulation. In vivo studies reveal neural responses in the context of intact neural circuits. Most importantly, recording of neural responses to behaviorally effective DBS in freely moving animals provides a direct means for examining how DBS modulates the basal ganglia thalamocortical circuits and thereby improves motor function. DBS can modulate firing rate, normalize irregular burst firing patterns and reduce low frequency oscillations associated with the Parkinsonian state. Our current efforts are focused on elucidating the mechanisms by which DBS effects on neural circuitry improve motor performance. New behavioral models and improved recording techniques will aide researchers conducting future DBS studies in a variety of behavioral modalities and enable new treatment strategies to be explored, such as closed-loop stimulations based on real time computation of ensemble neural activity.

  8. Brain-derived neurotrophic factor stimulates energy metabolism in developing cortical neurons.

    Science.gov (United States)

    Burkhalter, Julia; Fiumelli, Hubert; Allaman, Igor; Chatton, Jean-Yves; Martin, Jean-Luc

    2003-09-10

    Brain-derived neurotrophic factor (BDNF) promotes the biochemical and morphological differentiation of selective populations of neurons during development. In this study we examined the energy requirements associated with the effects of BDNF on neuronal differentiation. Because glucose is the preferred energy substrate in the brain, the effect of BDNF on glucose utilization was investigated in developing cortical neurons via biochemical and imaging studies. Results revealed that BDNF increases glucose utilization and the expression of the neuronal glucose transporter GLUT3. Stimulation of glucose utilization by BDNF was shown to result from the activation of Na+/K+-ATPase via an increase in Na+ influx that is mediated, at least in part, by the stimulation of Na+-dependent amino acid transport. The increased Na+-dependent amino acid uptake by BDNF is followed by an enhancement of overall protein synthesis associated with the differentiation of cortical neurons. Together, these data demonstrate the ability of BDNF to stimulate glucose utilization in response to an enhanced energy demand resulting from increases in amino acid uptake and protein synthesis associated with the promotion of neuronal differentiation by BDNF.

  9. Central thalamic deep brain stimulation for support of forebrain arousal regulation in the minimally conscious state.

    Science.gov (United States)

    Schiff, Nicholas D

    2013-01-01

    This chapter considers the use of central thalamic deep brain stimulation (CT/DBS) to support arousal regulation mechanisms in the minimally conscious state (MCS). CT/DBS for selected patients in a MCS is first placed in the historical context of prior efforts to use thalamic electrical brain stimulation to treat the unconscious clinical conditions of coma and vegetative state. These previous studies and a proof of concept result from a single-subject study of a patient in a MCS are reviewed against the background of new population data providing benchmarks of the natural history of vegetative and MCSs. The conceptual foundations for CT/DBS in selected patients in a MCS are then presented with consideration of both circuit and cellular mechanisms underlying recovery of consciousness identified from empirical studies. Directions for developing future generalizable criteria for CT/DBS that focus on the integrity of necessary brain systems and behavioral profiles in patients in a MCS that may optimally response to support of arousal regulation mechanisms are proposed.

  10. Effects of alternating current stimulation on the healthy and diseased brain

    Directory of Open Access Journals (Sweden)

    Aini Ismafairus eAbd Hamid

    2015-10-01

    Full Text Available Cognitive and neurological dysfunctions can severely impact a patient’s daily activities. In addition to medical treatment, non-invasive transcranial alternating current stimulation (tACS has been proposed as a therapeutic technique to improve the functional state of the brain. Although during the last years tACS was applied in numerous studies to improve motor, somatosensory, visual and higher order cognitive functions, our knowledge is still limited regarding the mechanisms as to which type of ACS can affect cortical functions and altered neuronal oscillations seem to be the key mechanism. Because alternating current send pulses to the brain at predetermined frequencies, the online- and after-effects of ACS strongly depend on the stimulation parameters so that ‘optimal’ ACS paradigms could be achieved. This is of interest not only for neuroscience research but also for clinical practice. In this study, we summarize recent findings on ACS-effects under both normal conditions and in brain diseases.

  11. Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding.

    Science.gov (United States)

    Kirov, Roumen; Weiss, Carsten; Siebner, Hartwig R; Born, Jan; Marshall, Lisa

    2009-09-08

    The application of transcranial slow oscillation stimulation (tSOS; 0.75 Hz) was previously shown to enhance widespread endogenous EEG slow oscillatory activity when applied during a sleep period characterized by emerging endogenous slow oscillatory activity. Processes of memory consolidation typically occurring during this state of sleep were also enhanced. Here, we show that the same tSOS applied in the waking brain also induced an increase in endogenous EEG slow oscillations (0.4-1.2 Hz), although in a topographically restricted fashion. Applied during wakefulness tSOS, additionally, resulted in a marked and widespread increase in EEG theta (4-8 Hz) activity. During wake, tSOS did not enhance consolidation of memories when applied after learning, but improved encoding of hippocampus-dependent memories when applied during learning. We conclude that the EEG frequency and related memory processes induced by tSOS critically depend on brain state. In response to tSOS during wakefulness the brain transposes stimulation by responding preferentially with theta oscillations and facilitated encoding.

  12. Modulating Endogenous Electric Currents in Human Corneal Wounds—A Novel Approach of Bioelectric Stimulation Without Electrodes

    Science.gov (United States)

    Reid, Brian; Graue-Hernandez, Enrique O.; Mannis, Mark J.; Zhao, Min

    2011-01-01

    Purpose To measure electric current in human corneal wounds and test the feasibility of pharmacologically enhancing the current to promote corneal wound healing. Methods Using a noninvasive vibrating probe, corneal electric current was measured before and after wounding of the epithelium of donated postmortem human corneas. The effects of drug aminophylline and chloride-free solution on wound current were also tested. Results Unwounded cornea had small outward currents (0.07 μA/cm2). Wounding increased the current more than 5 fold (0.41 μA/cm2). Monitoring the wound current over time showed that it seemed to be actively regulated and maintained above normal unwounded levels for at least 6 hours. The time course was similar to that previously measured in rat cornea. Drug treatment or chloride-free solution more than doubled the size of wound currents. Conclusions Electric current at human corneal wounds can be significantly increased with aminophylline or chloride-free solution. Because corneal wound current directly correlates with wound healing rate, our results suggest a role for chloride-free and/or aminophylline eyedrops to enhance healing of damaged cornea in patients with reduced wound healing such as the elderly or diabetic patient. This novel approach offers bioelectric stimulation without electrodes and can be readily tested in patients. PMID:21099404

  13. Upper-limb stroke rehabilitation using electrode-array based functional electrical stimulation with sensing and control innovations.

    Science.gov (United States)

    Kutlu, M; Freeman, C T; Hallewell, E; Hughes, A-M; Laila, D S

    2016-04-01

    Functional electrical stimulation (FES) has shown effectiveness in restoring upper-limb movement post-stroke when applied to assist participants' voluntary intention during repeated, motivating tasks. Recent clinical trials have used advanced controllers that precisely adjust FES to assist functional reach and grasp tasks with FES applied to three muscle groups, showing significant reduction in impairment. The system reported in this paper advances the state-of-the-art by: (1) integrating an FES electrode array on the forearm to assist complex hand and wrist gestures; (2) utilising non-contact depth cameras to accurately record the arm, hand and wrist position in 3D; and (3) employing an interactive touch table to present motivating virtual reality (VR) tasks. The system also uses iterative learning control (ILC), a model-based control strategy which adjusts the applied FES based on the tracking error recorded on previous task attempts. Feasibility of the system has been evaluated in experimental trials with 2 unimpaired participants and clinical trials with 4 hemiparetic, chronic stroke participants. The stroke participants attended 17, 1 hour training sessions in which they performed functional tasks, such as button pressing using the touch table and closing a drawer. Stroke participant results show that the joint angle error norm reduced by an average of 50.3% over 6 attempts at each task when assisted by FES.

  14. Cognitive and Neurophysiological Effects of Non-invasive Brain Stimulation in Stroke Patients after Motor Rehabilitation.

    Science.gov (United States)

    D'Agata, Federico; Peila, Elena; Cicerale, Alessandro; Caglio, Marcella M; Caroppo, Paola; Vighetti, Sergio; Piedimonte, Alessandro; Minuto, Alice; Campagnoli, Marcello; Salatino, Adriana; Molo, Maria T; Mortara, Paolo; Pinessi, Lorenzo; Massazza, Giuseppe

    2016-01-01

    The primary aim of this study was to evaluate and compare the effectiveness of two specific Non-Invasive Brain Stimulation (NIBS) paradigms, the repetitive Transcranial Magnetic Stimulation (rTMS), and transcranial Direct Current Stimulation (tDCS), in the upper limb rehabilitation of patients with stroke. Short and long term outcomes (after 3 and 6 months, respectively) were evaluated. We measured, at multiple time points, the manual dexterity using a validated clinical scale (ARAT), electroencephalography auditory event related potentials, and neuropsychological performances in patients with chronic stroke of middle severity. Thirty four patients were enrolled and randomized. The intervention group was treated with a NIBS protocol longer than usual, applying a second cycle of stimulation, after a washout period, using different techniques in the two cycles (rTMS/tDCS). We compared the results with a control group treated with sham stimulation. We split the data analysis into three studies. In this first study we examined if a cumulative effect was clinically visible. In the second study we compared the effects of the two techniques. In the third study we explored if patients with minor cognitive impairment have most benefit from the treatment and if cognitive and motor outcomes were correlated. We found that the impairment in some cognitive domains cannot be considered an exclusion criterion for rehabilitation with NIBS. ERP improved, related to cognitive and attentional processes after stimulation on the motor cortex, but transitorily. This effect could be linked to the restoration of hemispheric balance or by the effects of distant connections. In our study the effects of the two NIBS were comparable, with some advantages using tDCS vs. rTMS in stroke rehabilitation. Finally we found that more than one cycle (2-4 weeks), spaced out by washout periods, should be used, only in responder patients, to obtain clinical relevant results.

  15. Speech disorders in Parkinson's disease: early diagnostics and effects of medication and brain stimulation.

    Science.gov (United States)

    Brabenec, L; Mekyska, J; Galaz, Z; Rektorova, Irena

    2017-03-01

    Hypokinetic dysarthria (HD) occurs in 90% of Parkinson's disease (PD) patients. It manifests specifically in the areas of articulation, phonation, prosody, speech fluency, and faciokinesis. We aimed to systematically review papers on HD in PD with a special focus on (1) early PD diagnosis and monitoring of the disease progression using acoustic voice and speech analysis, and (2) functional imaging studies exploring neural correlates of HD in PD, and (3) clinical studies using acoustic analysis to evaluate effects of dopaminergic medication and brain stimulation. A systematic literature search of articles written in English before March 2016 was conducted in the Web of Science, PubMed, SpringerLink, and IEEE Xplore databases using and combining specific relevant keywords. Articles were categorized into three groups: (1) articles focused on neural correlates of HD in PD using functional imaging (n = 13); (2) articles dealing with the acoustic analysis of HD in PD (n = 52); and (3) articles concerning specifically dopaminergic and brain stimulation-related effects as assessed by acoustic analysis (n = 31); the groups were then reviewed. We identified 14 combinations of speech tasks and acoustic features that can be recommended for use in describing the main features of HD in PD. While only a few acoustic parameters correlate with limb motor symptoms and can be partially relieved by dopaminergic medication, HD in PD seems to be mainly related to non-dopaminergic deficits and associated particularly with non-motor symptoms. Future studies should combine non-invasive brain stimulation with voice behavior approaches to achieve the best treatment effects by enhancing auditory-motor integration.

  16. Non-invasive brain stimulation enhances the effects of Melodic Intonation Therapy

    Directory of Open Access Journals (Sweden)

    Bradley W. Vines

    2011-09-01

    Full Text Available Research has suggested that a fronto-temporal network in the right hemisphere may be responsible for mediating Melodic Intonation Therapy’s positive effects on speech recovery. We investigated the potential for a non-invasive brain stimulation technique, transcranial direct current stimulation (tDCS, to augment the benefits of MIT in patients with non-fluent aphasia by modulating neural activity in the brain during treatment with MIT. The polarity of the current applied to the scalp determines the effects of tDCS on the underlying tissue: anodal tDCS increases excitability, whereas cathodal tDCS decreases excitability. We applied anodal tDCS to the posterior inferior frontal gyrus (IFG of the right hemisphere, an area that has been shown to both contribute to singing through the mapping of sounds to ariculatory actions and serve as a key region in the process of recovery from aphasia, particularly in patients with large left hemispheric lesions. The stimulation was applied while patients were treated with MIT by a trained therapist. Six patients with moderate to severe non-fluent aphasia underwent three consecutive days of anodal-tDCS+MIT, and an equivalent series of sham-tDCS+MIT. The two treatment series were separated by one week, and the order in which the treatments were administered was randomized. Compared to the effects of sham-tDCS+MIT, anodal-tDCS+MIT led to significant improvements in fluency of speech. These results support the hypothesis that, as the brain seeks to reorganize and compensate for damage to left-hemisphere language centers, combining anodal-tDCS with MIT may further recovery from post-stroke aphasia by enhancing activity in a right-hemisphere sensorimotor network for articulation.

  17. Role of adenosine in the antiepileptic effects of deep brain stimulation

    Science.gov (United States)

    Miranda, Maisa F.; Hamani, Clement; de Almeida, Antônio-Carlos G.; Amorim, Beatriz O.; Macedo, Carlos E.; Fernandes, Maria José S.; Nobrega, José N.; Aarão, Mayra C.; Madureira, Ana Paula; Rodrigues, Antônio M.; Andersen, Monica L.; Tufik, Sergio; Mello, Luiz E.; Covolan, Luciene

    2014-01-01

    Despite the effectiveness of anterior thalamic nucleus (AN) deep brain stimulation (DBS) for the treatment of epilepsy, mechanisms responsible for the antiepileptic effects of this therapy remain elusive. As adenosine modulates neuronal excitability and seizure activity in animal models, we hypothesized that this nucleoside could be one of the substrates involved in the effects of AN DBS. We applied 5 days of stimulation to rats rendered chronically epileptic by pilocarpine injections and recorded epileptiform activity in hippocampal slices. We found that slices from animals given DBS had reduced hippocampal excitability and were less susceptible to develop ictal activity. In live animals, AN DBS significantly increased adenosine levels in the hippocampus as measured by microdialysis. The reduced excitability of DBS in vitro was completely abolished in animals pre-treated with A1 receptor antagonists and was strongly potentiated by A1 receptor agonists. We conclude that some of the antiepileptic effects of DBS may be mediated by adenosine. PMID:25324724

  18. Voice features of Parkinson's disease patients with subthalamic nucleus deep brain stimulation.

    Science.gov (United States)

    Tanaka, Yasuhiro; Tsuboi, Takashi; Watanabe, Hirohisa; Kajita, Yasukazu; Fujimoto, Yasushi; Ohdake, Reiko; Yoneyama, Noritaka; Masuda, Michihito; Hara, Kazuhiro; Senda, Joe; Ito, Mizuki; Atsuta, Naoki; Horiguchi, Satoshi; Yamamoto, Masahiko; Wakabayashi, Toshihiko; Sobue, Gen

    2015-05-01

    Voice and speech disorders are one of the most important issues after subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease patients; however, their characteristics remain unclear. We performed a comprehensive voice evaluation including the multi-dimensional voice program for acoustic analysis, the GRBAS scale for perceptual analysis, and the evaluation of the voice handicap index (VHI) for psychosocial analysis. In total, 68 patients who had undergone STN-DBS (37 assessed in the on- and off-stimulation conditions) and 40 who had been treated with medical therapy alone were evaluated. Further, we performed laryngoscopic examinations in 13 STN-DBS and 19 medical-therapy-alone patients. The STN-DBS group, especially females, showed widespread impairment of voice parameters and significantly poorer VHI scores than the medical-therapy-alone group. The degree of voiceless (DUV) and strained voice were the most impaired factors in the STN-DBS group; and DUV significantly improved after stopping stimulation. Furthermore strained voice, breathiness, and asthenia improved after stopping stimulation. Laryngoscopic examination showed that abnormal laryngeal muscle contraction and incomplete glottal closure were more prominent in the STN-DBS group than in the medical-therapy-alone group. We demonstrated that (1) more widespread voice impairment in females, (2) poorer voice-related QOL, (3) worse DUV and strained voice, and (4) abnormal laryngeal muscle contraction were the characteristic voice and laryngeal findings in the STN-DBS group compared with those in the medical-therapy-alone group.

  19. Anesthetic management of deep brain stimulator implantation in Meige′s syndrome

    Directory of Open Access Journals (Sweden)

    Kalpesh V Bhoyar

    2012-01-01

    Full Text Available Meige′s syndrome is rare form of orofacial dystonia. There is unfortunately no cure, but occasionally patients may improve with time. We present the successful management of a palladial deep brain stimulator (DBS implantation for Meige′s syndrome. Dexmedetomidine infusion was used for sedation. The procedure lasted for around 12 h and the patient was comfortable, responsive, and cooperative over the extended period of time. The surgeons were comfortable with electrophysiologic brain mapping and clinical testing. DBS were implanted, through a burr hole, into the globus pallidus neurophysiological testing under guidance. The pulse generator battery was subcutaneously implanted into the chest wall under general anesthesia. The implanted pulse generator battery was started 2 days later and the patient showed dramatic improvement in his symptoms.

  20. Pallidal deep brain stimulation in a 5-year-old child with dystonic storm: case report.

    Science.gov (United States)

    Aydin, Sabri; Abuzayed, Bashar; Uysal, Serap; Unver, Olcay; Uzan, Mustafa; Mengi, Murat; Kizilkilic, Osman; Hanci, Murat

    2013-01-01

    A 5-year-old child had a medical history of epilepsy and a newly presented mental retardation with a life-threatening dystonic storm. Neuroimagings showed bilateral calcification of the pallidum. Several treatment modalities were performed, but the symptoms showed no significant improvement. The patient was operated on in order to place a deep brain stimulation (DBS) targeting bilateral globus pallidum internus (GPi). The dystonia showed a remarkable improvement after surgery, with 81% reduction of dystonia severity after 15 months. To our best knowledge, this is the youngest patient mentioned in the literature to be treated with DBS, which was also life-saving in this case.

  1. Proceedings of the Second Annual Deep Brain Stimulation Think Tank: What's in the Pipeline.

    Science.gov (United States)

    Gunduz, Aysegul; Morita, Hokuto; Rossi, P Justin; Allen, William L; Alterman, Ron L; Bronte-Stewart, Helen; Butson, Christopher R; Charles, David; Deckers, Sjaak; de Hemptinne, Coralie; DeLong, Mahlon; Dougherty, Darin; Ellrich, Jens; Foote, Kelly D; Giordano, James; Goodman, Wayne; Greenberg, Benjamin D; Greene, David; Gross, Robert; Judy, Jack W; Karst, Edward; Kent, Alexander; Kopell, Brian; Lang, Anthony; Lozano, Andres; Lungu, Codrin; Lyons, Kelly E; Machado, Andre; Martens, Hubert; McIntyre, Cameron; Min, Hoon-Ki; Neimat, Joseph; Ostrem, Jill; Pannu, Sat; Ponce, Francisco; Pouratian, Nader; Reymers, Donnie; Schrock, Lauren; Sheth, Sameer; Shih, Ludy; Stanslaski, Scott; Steinke, G Karl; Stypulkowski, Paul; Tröster, Alexander I; Verhagen, Leo; Walker, Harrison; Okun, Michael S

    2015-01-01

    The proceedings of the 2nd Annual Deep Brain Stimulation Think Tank summarize the most contemporary clinical, electrophysiological, and computational work on DBS for the treatment of neurological and neuropsychiatric disease and represent the insights of a unique multidisciplinary ensemble of expert neurologists, neurosurgeons, neuropsychologists, psychiatrists, scientists, engineers and members of industry. Presentations and discussions covered a broad range of topics, including advocacy for DBS, improving clinical outcomes, innovations in computational models of DBS, understanding of the neurophysiology of Parkinson's disease (PD) and Tourette syndrome (TS) and evolving sensor and device technologies.

  2. The Third Annual Deep Brain Stimulation Think Tank: A Review of Emerging Issues and Technologies

    Directory of Open Access Journals (Sweden)

    P. Justin eRossi

    2016-04-01

    Full Text Available This review summarizes the most contemporary clinical, electrophysiological, imaging, and computational work on DBS for the treatment of neurological and neuropsychiatric disease. Significant innovations of the past year are emphasized; these advances were presented at the 3rd Annual Deep Brain Stimulation Think Tank. The Think Tank’s contributors represent a unique multidisciplinary ensemble of expert neurologists, neurosurgeons, neuropsychologists, psychiatrists, scientists, engineers, and members of industry. Presentations and discussions covered a broad range of topics, including policy and advocacy considerations for the future of DBS, connectomic approaches to DBS targeting, developments in electrophysiology and related strides toward responsive DBS systems, and recent developments in sensor and device technologies.

  3. Patient Perspectives on Deep Brain Stimulation Clinical Research in Early Stage Parkinson's Disease.

    Science.gov (United States)

    Heusinkveld, Lauren; Hacker, Mallory; Turchan, Maxim; Bollig, Madelyn; Tamargo, Christina; Fisher, William; McLaughlin, Lauren; Martig, Adria; Charles, David

    2017-01-01

    The FDA has approved a multicenter, double-blind, Phase III, pivotal trial testing deep brain stimulation (DBS) in 280 people with very early stage Parkinson's disease (PD; IDE#G050016). In partnership with The Michael J. Fox Foundation for Parkinson's Research, we conducted a survey to investigate motivating factors, barriers, and gender differences among potentially eligible patients for participation in a trial testing DBS in early PD compared to standard medical treatment. The majority of survey respondents (72%) indicated they would consider learning more about participating. Early PD patients are therefore likely to consider enrolling in trials of invasive therapies that may slow symptom progression and help future patients.

  4. Deep brain stimulation of the nucleus accumbens for the treatment of addiction.

    Science.gov (United States)

    Müller, Ulf J; Voges, Jürgen; Steiner, Johann; Galazky, Imke; Heinze, Hans-Jochen; Möller, Michaela; Pisapia, Jared; Halpern, Casey; Caplan, Arthur; Bogerts, Bernhard; Kuhn, Jens

    2013-04-01

    Despite novel medications and other therapeutic strategies, addiction to psychotropic substances remains one of the most serious public health problems worldwide. In this review, beginning with an introduction of deep brain stimulation (DBS), we highlight the importance of the nucleus accumbens (NAc) in the context of the reward circuitry and addictive behavior. We will provide a short historic overview of other neurosurgical approaches to treat addiction and describe the experimental and preclinical data on DBS in addiction. Finally, we call attention to key ethical issues related to using DBS to treat addiction that are important for future research and the design of clinical trials.

  5. New Insights Offered by a Computational Model of Deep Brain Stimulation

    DEFF Research Database (Denmark)

    Modolo, J.; Mosekilde, Erik; Beuter, A.

    2007-01-01

    Deep brain stimulation (DBS) is a standard neurosurgical procedure used to treat motor symptoms in about 5% of patients with Parkinson's disease (PD). Despite the indisputable success of this procedure, the biological mechanisms underlying the clinical benefits of DBS have not yet been fully...... elucidated. The paper starts with a brief review on the use of DBS to treat PD symptoms. The second section introduces a computational model based on the population density approach and the Izhikevich neuron model. We explain why this model is appropriate for investigating macroscopic network effects...

  6. Weight and body mass index in Parkinson's disease patients after deep brain stimulation surgery.

    Science.gov (United States)

    Tuite, Paul J; Maxwell, Robert E; Ikramuddin, Sayeed; Kotz, Catherine M; Kotzd, Catherine M; Billington, Charles J; Billingtond, Charles J; Laseski, Maggie A; Thielen, Scott D

    2005-06-01

    A retrospective chart review characterizing changes in 17 male and 10 female Parkinson's disease (PD) patients undergoing deep brain stimulation (DBS) surgery indicated that 6 mo before surgery, patients lost a mean of 5.1 lbs, whereas in the 6 mo after surgery, subjects gained a mean of 10.1 lbs; 22% gained more than 14 lbs. In 10 patients followed an additional 6 mo, weight gain continued. This weight gain may be associated with decreased energy expenditure due to subsidence of chronic tremor. The magnitude of gain underscores the need for proactive management of body weight in PD patients undergoing DBS.

  7. Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding

    DEFF Research Database (Denmark)

    Kirov, Roumen; Weiss, Carsten; Siebner, Hartwig R;

    2009-01-01

    typically occurring during this state of sleep were also enhanced. Here, we show that the same tSOS applied in the waking brain also induced an increase in endogenous EEG slow oscillations (0.4-1.2 Hz), although in a topographically restricted fashion. Applied during wakefulness tSOS, additionally, resulted......The application of transcranial slow oscillation stimulation (tSOS; 0.75 Hz) was previously shown to enhance widespread endogenous EEG slow oscillatory activity when applied during a sleep period characterized by emerging endogenous slow oscillatory activity. Processes of memory consolidation...

  8. Does non-invasive brain stimulation improve cognition in major depressive disorder? A systematic review.

    Science.gov (United States)

    Tortella, Gabriel; Selingardi, Priscila M L; Moreno, Marina L; Veronezi, Beatriz P; Brunoni, Andre R

    2014-01-01

    Non-invasive brain stimulation (NIBS) techniques, such as repeated transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), have been increasingly used in different contexts to improve cognitive performance and ameliorate depression symptoms. Considering that major depression is usually accompanied by cognitive deficits, NIBS technique could be also helpful to improve cognition in depressed patients. In this systematic review, we researched for articles published in PubMed/MEDLINE from the first date available to June 2014 that assessed cognitive performance in patients with depression before and after NIBS. Out of 191 references, 25 (16 for rTMS and 9 for tDCS) studies matched our eligibility criteria. Non-invasive brain stimulation interventions, such as rTMS and tDCS seem to be a promising tool for cognitive enhancement in MDD, although several issues and biases (e.g., blinding issues, tests without correction for multiple comparisons, placebo effects and exploratory analyses, practice effects) hinder us to conclude that NIBS technique improve cognition in patients with depression. We discussed possible shortcomings of the included studies, such as the use of different depression treatment protocols, the possibility that some findings were false-positive results of the employed cognitive tasks and whether cognition improvement could have been an epiphenomenon secondary to depression improvement. To conclude, whereas these non-pharmacological, non-invasive techniques are particularly appealing for cognitive improvement in depression, further studies are still warranted to disentangle whether NIBS technique induce positive effects on cognition beyond their antidepressant effects.

  9. Effective range of electrical stimulation in brain silica preparation; No slice hyohon ni okeru denki shigeki koka han`i no kento

    Energy Technology Data Exchange (ETDEWEB)

    Takimori, T.; Ogawa, T.; Nishida, M. [Akita University, Akita (Japan)

    1997-08-20

    In order to examine the confines of electrical stimulation in layer 2/3 of visual cortex in the brain slice preparation, we estimated the effective range of the stimulation based on the excitatory postsynaptic potential (EPSP) evoked in layer V neuron which receives input from layer 2/3. For this purpose, we recorded and compared EPSPs amplitudes evoked by stimulations at directly over site of recording electrode and lateral site in layer 2/3. Since the EPSP increased linearly with stimulus intensity before the saturation, it was considered that the EPSP correlates with the number of projecting neurons in area directly excited with the stimulation. Then we formed the region model by which we can get the ratios between the neuron numbers in areas excited by different sites stimulations against the stimulus effective ranges. And in the stimulus intensity for action potential threshold of layer 5 neuron, we evaluated the effective range for the relative values of EPSPs to be produced with the stimulations of 250{mu}m lateral site and directory over site. In the model, the ratio increased monotonically with the effective range and in the case of 250{mu}m for the effective range, the ratio between those EPSPs was less than the value in the model. These results led the conclusion that the effective range of the intensity for layer 5 neuron to generate the output is confined within 250{mu}m from directly over site, that is, within layer 2/3. 7 refs., 11 figs., 1 tab.

  10. Insulin Stimulates S100B Secretion and These Proteins Antagonistically Modulate Brain Glucose Metabolism.

    Science.gov (United States)

    Wartchow, Krista Minéia; Tramontina, Ana Carolina; de Souza, Daniela F; Biasibetti, Regina; Bobermin, Larissa D; Gonçalves, Carlos-Alberto

    2016-06-01

    Brain metabolism is highly dependent on glucose, which is derived from the blood circulation and metabolized by the astrocytes and other neural cells via several pathways. Glucose uptake in the brain does not involve insulin-dependent glucose transporters; however, this hormone affects the glucose influx to the brain. Changes in cerebrospinal fluid levels of S100B (an astrocyte-derived protein) have been associated with alterations in glucose metabolism; however, there is no evidence whether insulin modulates glucose metabolism and S100B secretion. Herein, we investigated the effect of S100B on glucose metabolism, measuring D-(3)H-glucose incorporation in two preparations, C6 glioma cells and acute hippocampal slices, and we also investigated the effect of insulin on S100B secretion. Our results showed that: (a) S100B at physiological levels decreases glucose uptake, through the multiligand receptor RAGE and mitogen-activated protein kinase/ERK signaling, and (b) insulin stimulated S100B secretion via PI3K signaling. Our findings indicate the existence of insulin-S100B modulation of glucose utilization in the brain tissue, and may improve our understanding of glucose metabolism in several conditions such as ketosis, streptozotocin-induced dementia and pharmacological exposure to antipsychotics, situations that lead to changes in insulin signaling and extracellular levels of S100B.

  11. Finite Element Modeling of Cutaneous Electrical Stimulation for Sensory Feedback

    Institute of Scientific and Technical Information of China (English)

    LI Si; CHAI Guo-hong; SUI Xiao-hong; LAN Ning

    2014-01-01

    It is currently difficult for the amputee to perceive environmental information such as tactile pressure on the fingertip of the present upper limb prostheses. Sensory feedback induced by cutaneous electrical stimulation can be used to transmit tactile information from hand prostheses to sensory nerve of intact upper arm, thus producing the corresponding perceptions in human brain. In order to have a deeper understanding on the distribution of stimulation current within the limb, and find a better placement of the stimulating and reference electrodes, we constructed a three-dimensional upper-limb model to systematically study the effect of electrode placement on current distribution based on finite element analysis. In these simulations, the reference electrode is positioned at four different locations around and on the axial direction of the arm. The results show that with the increase of distance between reference electrode and stimulating electrode, the current density increases in the skin layer of the upper limb. When the reference electrode is on the opposite side of stimulating electrode around the arm, the current is more concentrated in the skin layer, which is in line with recent findings in psychophysiological experiments. But better spatial selectivity could be achieved when the reference electrode is closer to the stimulating electrode around the arm, and it is more obvious in comparison with that on the axial direction. These findings will provide insights for the design of electrode array used for evoking cutaneous sensory afferents.

  12. Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation.

    Directory of Open Access Journals (Sweden)

    Katsuya Kobayashi

    Full Text Available Physiological high frequency activities (HFA are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections, or different terminal layers (layer IV vs. layer II/III affect its frequency, we, in the primary somatosensory cortex (SI, compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response and N80 (late response of somatosensory evoked potentials (HFA(SEP(N20 and HFA(SEP(N80 and compared those overriding N1 and N2 (first and second responses of cortico-cortical evoked potentials (HFA(CCEP(N1 and HFA(CCEP(N2. HFA(SEP(N20 showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1 had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1 and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.

  13. A cross validation study of deep brain stimulation targeting: from experts to atlas-based, segmentation-based and automatic registration algorithms.

    Science.gov (United States)

    Castro, F Javier Sanchez; Pollo, Claudio; Meuli, Reto; Maeder, Philippe; Cuisenaire, Olivier; Cuadra, Meritxell Bach; Villemure, Jean-Guy; Thiran, Jean-Philippe

    2006-11-01

    Validation of image registration algorithms is a difficult task and open-ended problem, usually application-dependent. In this paper, we focus on deep brain stimulation (DBS) targeting for the treatment of movement disorders like Parkinson's disease and essential tremor. DBS involves implantation of an electrode deep inside the brain to electrically stimulate specific areas shutting down the disease's symptoms. The subthalamic nucleus (STN) has turned out to be the optimal target for this kind of surgery. Unfortunately, the STN is in general not clearly distinguishable in common medical imaging modalities. Usual techniques to infer its location are the use of anatomical atlases and visible surrounding landmarks. Surgeons have to adjust the electrode intraoperatively using electrophysiological recordings and macrostimulation tests. We constructed a ground truth derived from specific patients whose STNs are clearly visible on magnetic resonance (MR) T2-weighted images. A patient is chosen as atlas both for the right and left sides. Then, by registering each patient with the atlas using different methods, several estimations of the STN location are obtained. Two studies are driven using our proposed validation scheme. First, a comparison between different atlas-based and nonrigid registration algorithms with a evaluation of their performance and usability to locate the STN automatically. Second, a study of which visible surrounding structures influence the STN location. The two studies are cross validated between them and against expert's variability. Using this scheme, we evaluated the expert's ability against the estimation error provided by the tested algorithms and we demonstrated that automatic STN targeting is possible and as accurate as the expert-driven techniques currently used. We also show which structures have to be taken into account to accurately estimate the STN location.

  14. Electrophoretic deposition of ligand-free platinum nanoparticles on neural electrodes affects their impedance in vitro and in vivo with no negative effect on reactive gliosis

    OpenAIRE

    Angelov, Svilen D.; Koenen, Sven; Jakobi, Jurij; Heissler, Hans E.; Alam, Mesbah; Schwabe, Kerstin; Barcikowski, Stephan; Krauss, Joachim K.

    2016-01-01

    Background Electrodes for neural stimulation and recording are used for the treatment of neurological disorders. Their features critically depend on impedance and interaction with brain tissue. The effect of surface modification on electrode impedance was examined in vitro and in vivo after intracranial implantation in rats. Electrodes coated by electrophoretic deposition with platinum nanoparticles (NP;

  15. Applying dynamic data collection to improve dry electrode system performance for a P300-based brain-computer interface

    Science.gov (United States)

    Clements, J. M.; Sellers, E. W.; Ryan, D. B.; Caves, K.; Collins, L. M.; Throckmorton, C. S.

    2016-12-01

    Objective. Dry electrodes have an advantage over gel-based ‘wet’ electrodes by providing quicker set-up time for electroencephalography recording; however, the potentially poorer contact can result in noisier recordings. We examine the impact that this may have on brain-computer interface communication and potential approaches for mitigation. Approach. We present a performance comparison of wet and dry electrodes for use with the P300 speller system in both healthy participants and participants with communication disabilities (ALS and PLS), and investigate the potential for a data-driven dynamic data collection algorithm to compensate for the lower signal-to-noise ratio (SNR) in dry systems. Main results. Performance results from sixteen healthy participants obtained in the standard static data collection environment demonstrate a substantial loss in accuracy with the dry system. Using a dynamic stopping algorithm, performance may have been improved by collecting more data in the dry system for ten healthy participants and eight participants with communication disabilities; however, the algorithm did not fully compensate for the lower SNR of the dry system. An analysis of the wet and dry system recordings revealed that delta and theta frequency band power (0.1-4 Hz and 4-8 Hz, respectively) are consistently higher in dry system recordings across participants, indicating that transient and drift artifacts may be an issue for dry systems. Significance. Using dry electrodes is desirable for reduced set-up time; however, this study demonstrates that online performance is significantly poorer than for wet electrodes for users with and without disabilities. We test a new application of dynamic stopping algorithms to compensate for poorer SNR. Dynamic stopping improved dry system performance; however, further signal processing efforts are likely necessary for full mitigation.

  16. Brain activity modification produced by a single radioelectric asymmetric brain stimulation pulse: a new tool for neuropsychiatric treatments. Preliminary fMRI study

    Directory of Open Access Journals (Sweden)

    Castagna A

    2011-10-01

    Full Text Available Salvatore Rinaldi1,2, Vania Fontani1, Alessandro Castagna1 1Department of Neuro-Psycho-Physio Pathology, Rinaldi Fontani Institute, Florence, Italy; 2Medical School of Occupational Medicine, University of Florence, Florence, Italy Purpose: Radioelectric asymmetric brain stimulation technology with its treatment protocols has shown efficacy in various psychiatric disorders. The aim of this work was to highlight the mechanisms by which these positive effects are achieved. The current study was conducted to determine whether a single 500-millisecond radioelectric asymmetric conveyor (REAC brain stimulation pulse (BSP, applied to the ear, can effect a modification of brain activity that is detectable using functional magnetic resonance imaging (fMRI. Methods: Ten healthy volunteers, six females and four males, underwent fMRI during a simple finger-tapping motor task before and after receiving a single 500-millisecond REAC-BSP. Results: The fMRI results indicate that the average variation in task-induced encephalic activation patterns is lower in subjects following the single REAC pulse. Conclusion: The current report demonstrates that a single REAC-BSP is sufficient to modulate brain activity in awake subjects, able to be measured using fMRI. These initial results open new perspectives into the understanding of the effects of weak and brief radio pulses upon brain activity, and provide the basis for further indepth studies using REAC-BSP and fMRI. Keywords: fMRI, brain stimulation, brain modulation, REAC, neuropsychiatric treatments

  17. Deep brain stimulation or thalamotomy in fragile X-associated tremor/ataxia syndrome? Case report.

    Science.gov (United States)

    Tamás, Gertrúd; Kovács, Norbert; Varga, Noémi Ágnes; Barsi, Péter; Erőss, Loránd; Molnár, Mária Judit; Balás, István

    2016-01-01

    We present the case of a 66-year-old man who has been treated for essential tremor since the age of 58. He developed mild cerebellar gait ataxia seven years after tremor onset. Moderate, global brain atrophy was identified on MRI scans. At the age of 68, only temporary tremor relief could be achieved by bilateral deep brain stimulation of the ventral intermedius nucleus of the thalamus. Bilateral stimulation of the subthalamic nucleus also resulted only in transient improvement. In the meantime, progressive gait ataxia and tetraataxia developed accompanied by other cerebellar symptoms, such as nystagmus and scanning speech. These correlated with progressive development of bilateral symmetric hyperintensity of the middle cerebellar peduncles on T2 weighted MRI scans. Genetic testing revealed premutation of the FMR1 gene, establishing the diagnosis of fragile X-associated tremor/ataxia syndrome. Although this is a rare disorder, it should be taken into consideration during preoperative evaluation of essential tremor. Postural tremor ceased two years later after thalamotomy on the left side, while kinetic tremor of the right hand also improved.

  18. VEGF-mediated angiogenesis stimulates neural stem cell proliferation and differentiation in the premature brain

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jinqiao, E-mail: jinqiao1977@163.com [Institute of Pediatrics, Children' s Hospital of Fudan University (China); Sha, Bin [Department of Neonatology, Children' s Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China); Zhou, Wenhao, E-mail: zhou_wenhao@yahoo.com.cn [Department of Neonatology, Children' s Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China); Yang, Yi [Institute of Pediatrics, Children' s Hospital of Fudan University (China)

    2010-03-26

    This study investigated the effects of angiogenesis on the proliferation and differentiation of neural stem cells in the premature brain. We observed the changes in neurogenesis that followed the stimulation and inhibition of angiogenesis by altering vascular endothelial growth factor (VEGF) expression in a 3-day-old rat model. VEGF expression was overexpressed by adenovirus transfection and down-regulated by siRNA interference. Using immunofluorescence assays, Western blot analysis, and real-time PCR methods, we observed angiogenesis and the proliferation and differentiation of neural stem cells. Immunofluorescence assays showed that the number of vWF-positive areas peaked at day 7, and they were highest in the VEGF up-regulation group and lowest in the VEGF down-regulation group at every time point. The number of neural stem cells, neurons, astrocytes, and oligodendrocytes in the subventricular zone gradually increased over time in the VEGF up-regulation group. Among the three groups, the number of these cells was highest in the VEGF up-regulation group and lowest in the VEGF down-regulation group at the same time point. Western blot analysis and real-time PCR confirmed these results. These data suggest that angiogenesis may stimulate the proliferation of neural stem cells and differentiation into neurons, astrocytes, and oligodendrocytes in the premature brain.

  19. Fatigue in multiple sclerosis: neural correlates and the role of non-invasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Moussa A. Chalah

    2015-11-01

    Full Text Available Multiple sclerosis (MS is a chronic progressive inflammatory disease of the central nervous system and the major cause of non-traumatic disability in young adults. Fatigue is a frequent symptom reported by the majority of MS patients during their disease course and drastically af-fects their quality of life. Despite its significant prevalence and impact, the underlying patho-physiological mechanisms are not well elucidated. MS fatigue is still considered the result of multifactorial and complex constellations, and is commonly classified into primary fatigue related to the pathological changes of the disease itself, and secondary fatigue attributed to mimicking symptoms, comorbid sleep and mood disorders, and medications side effects. Data from neuroimaging, neurophysiology, neuroendocrine and neuroimmune studies have raised hypotheses regarding the origin of this symptom, some of which have succeeded in identifying an association between MS fatigue and structural or functional abnormalities within various brain networks. Hence, the aim of this work is to reappraise the neural correlates of MS fatigue and to discuss the rationale for the emergent use of noninvasive brain stimulation (NIBS techniques as potential treatments. This will include a presentation of the various NIBS modalities and a proposition of their potential mechanisms of action in this context. Specific issues related to the value of transcranial direct current stimulation will be addressed.

  20. Transcriptomic Modification in the Cerebral Cortex following Noninvasive Brain Stimulation: RNA-Sequencing Approach

    Directory of Open Access Journals (Sweden)

    Ben Holmes

    2016-01-01

    Full Text Available Transcranial direct current stimulation (tDCS has been shown to modulate neuroplasticity. Beneficial effects are observed in patients with psychiatric disorders and enhancement of brain performance in healthy individuals has been observed following tDCS. However, few studies have attempted to elucidate the underlying molecular mechanisms of tDCS in the brain. This study was conducted to assess the impact of tDCS on gene expression within the rat cerebral cortex. Anodal tDCS was applied at 3 different intensities followed by RNA-sequencing and analysis. In each current intensity, approximately 1,000 genes demonstrated statistically significant differences compared to the sham group. A variety of functional pathways, biological processes, and molecular categories were found to be modified by tDCS. The impact of tDCS on gene expression was dependent on current intensity. Results show that inflammatory pathways, antidepressant-related pathways (GTP signaling, calcium ion binding, and transmembrane/signal peptide pathways, and receptor signaling pathways (serotonergic, adrenergic, GABAergic, dopaminergic, and glutamate were most affected. Of the gene expression profiles induced by tDCS, some changes were observed across multiple current intensities while other changes were unique to a single stimulation intensity. This study demonstrates that tDCS can modify the expression profile of various genes in the cerebral cortex and that these tDCS-induced alterations are dependent on the current intensity applied.

  1. A framework for identification of brain network dynamics using a novel binary noise modulated electrical stimulation pattern.

    Science.gov (United States)

    Yang, Yuxiao; Shanechi, Maryam M

    2015-01-01

    Modeling and identification of brain network dynamics is of great importance both for understanding brain function and for closed-loop control of brain states. In this work, we present a multi-input-multi-output (MIMO) linear state-space model (LSSM) to describe the brain network dynamics in response to electrical stimulation. The LSSM maps the parameters of electrical stimulation, such as frequency, amplitude and pulse-width to recorded brain signals such as electrocorticography (ECoG) and electroencephalography (EEG). Effective identification of the LSSM in open-loop stimulation experiments, however, is strongly dependent on the open-loop input stimulation design. We propose a novel input design to accurately identify the LSSM by integrating the concept of binary noise (BN) with practical constraints on stimulation waveforms. The designed input pattern is a pulse train modulated by stochastic BN parameters. We show that this input pattern both satisfies the necessary spectral condition for accurate system identification and can incorporate any desired pulse shape. Using numerical experiments, we show that the quality of identification depends heavily on the input signal pattern and the proposed binary noise modulated pattern achieves satisfactory identification results, reducing the relative estimation error more than 300 times compared with step sequence modulated, single-sinusoid modulated and multi-sinusoids modulated input patterns.

  2. Opposite modulation of brain stimulation reward by NMDA and AMPA receptors in the ventral tegmental area.

    Directory of Open Access Journals (Sweden)

    Charles eDucrot

    2013-10-01

    Full Text Available Previous studies have shown that blockade of ventral midbrain (VM glutamate N-Methyl-D-Aspartate (NMDA receptors induces reward, stimulates forward locomotion and enhances brain stimulation reward. Glutamate induces two types of excitatory response on VM neurons, a fast and short lasting depolarisation mediated by a-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA receptors and a longer lasting depolarization mediated by NMDA receptors. A role for the two glutamate receptors in modulation of VM neuronal activity is evidenced by the functional change in AMPA and NMDA synaptic responses that result from repeated exposure to reward. Since both receptors contribute to the action of glutamate on VM neuronal activity, we studied the effects of VM AMPA and NMDA receptor blockade on reward induced by electrical brain stimulation. Experiments were performed on rats trained to self-administer electrical pulses in the medial posterior mesencephalon. Reward thresholds were measured with the curve-shift paradigm before and for two hours after bilateral VM microinjections of the AMPA antagonist, NBQX (2,3,-Dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(fquinoxaline-7-sulfonamide, 0, 80, and 800 pmol/0.5ul/side and of a single dose (0.825 nmol/0.5ul/side of the NMDA antagonist, PPPA (2R,4S-4-(3-Phosphonopropyl-2-piperidinecarboxylic acid. NBQX produced a dose-dependent increase in reward threshold with no significant change in maximum rate of responding. Whereas PPPA injected at the same VM sites produced a significant time dependent decrease in reward threshold and increase in maximum rate of responding. We found a negative correlation between the magnitude of the attenuation effect of NBQX and the enhancement effect of PPPA; moreover, NBQX and PPPA were most effective when injected respectively into the anterior and posterior VM. These results suggest that glutamate acts on different receptor sub-types, most likely located on different VM neurons, to modulate

  3. Effects of STN and GPi deep brain stimulation on impulse control disorders and dopamine dysregulation syndrome.

    Directory of Open Access Journals (Sweden)

    Sarah J Moum

    Full Text Available OBJECTIVE: Impulse control disorders (ICDs and dopamine dysregulation syndrome (DDS are important behavioral problems that affect a subpopulation of patients with Parkinson's disease (PD and typically result in markedly diminished quality of life for patients and their caregivers. We aimed to investigate the effects of subthalamic nucleus (STN and internal globus pallidus (GPi deep brain stimulation (DBS on ICD/DDS frequency and dopaminergic medication usage. METHODS: A retrospective chart review was performed on 159 individuals who underwent unilateral or bilateral PD DBS surgery in either STN or GPi. According to published criteria, pre- and post-operative records were reviewed to categorize patients both pre- and post-operatively as having ICD, DDS, both ICD and DDS, or neither ICD nor DDS. Group differences in patient demographics, clinical presentations, levodopa equivalent dose (LED, and change in diagnosis following unilateral/bilateral by brain target (STN or GPi DBS placement were examined. RESULTS: 28 patients met diagnostic criteria for ICD or DDS pre- or post-operatively. ICD or DDS classification did not differ by GPi or STN target stimulation. There was no change in DDS diagnosis after unilateral or bilateral stimulation. For ICD, diagnosis resolved in 2 of 7 individuals after unilateral or bilateral DBS. Post-operative development of these syndromes was significant; 17 patients developed ICD diagnoses post-operatively with 2 patients with pre-operative ICD developing DDS post-operatively. CONCLUSIONS: Unilateral or bilateral DBS did not significantly treat DDS or ICD in our sample, even though a few cases of ICD resolved post-operatively. Rather, our study provides preliminary evidence that DDS and ICD diagnoses may emerge following DBS surgery.

  4. Opposite modulation of brain stimulation reward by NMDA and AMPA receptors in the ventral tegmental area.

    Science.gov (United States)

    Ducrot, Charles; Fortier, Emmanuel; Bouchard, Claude; Rompré, Pierre-Paul

    2013-01-01

    Previous studies have shown that blockade of ventral tegmental area (VTA) glutamate N-Methyl-D-Aspartate (NMDA) receptors induces reward, stimulates forward locomotion and enhances brain stimulation reward. Glutamate induces two types of excitatory response on VTA neurons, a fast and short lasting depolarization mediated by α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors and a longer lasting depolarization mediated by NMDA receptors. A role for the two glutamate receptors in modulation of VTA neuronal activity is evidenced by the functional change in AMPA and NMDA synaptic responses that result from repeated exposure to reward. Since both receptors contribute to the action of glutamate on VTA neuronal activity, we studied the effects of VTA AMPA and NMDA receptor blockade on reward induced by electrical brain stimulation. Experiments were performed on rats trained to self-administer electrical pulses in the medial posterior mesencephalon. Reward thresholds were measured with the curve-shift paradigm before and for 2 h after bilateral VTA microinjections of the AMPA antagonist, NBQX (2,3,-Dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(f)quinoxaline-7-sulfonamide, 0, 80, and 800 pmol/0.5 μl/side) and of a single dose (0.825 nmol/0.5 μl/side) of the NMDA antagonist, PPPA (2R,4S)-4-(3-Phosphonopropyl)-2-piperidinecarboxylic acid). NBQX produced a dose-dependent increase in reward threshold with no significant change in maximum rate of responding. Whereas PPPA injected at the same VTA sites produced a significant time dependent decrease in reward threshold and increase in maximum rate of responding. We found a negative correlation between the magnitude of the attenuation effect of NBQX and the enhancement effect of PPPA; moreover, NBQX and PPPA were most effective when injected, respectively, into the anterior and posterior VTA. These results suggest that glutamate acts on different receptor sub-types, most likely located on different VTA neurons, to

  5. Brain SPECT guided repetitive transcranial magnetic stimulation (rTMS) in treatment resistant major depressive disorder.

    Science.gov (United States)

    Jha, Shailesh; Chadda, Rakesh K; Kumar, Nand; Bal, C S

    2016-06-01

    Repetitive transcranial magnetic stimulation (rTMS) has emerged as a potential treatment in treatment resistant major depressive disorder (MDD). However, there is no consensus about the exact site of stimulation for rTMS. Single-photon emission computed tomography (SPECT) offers a potential technique in deciding the site of stimulation. The present study was conducted to assess the difference in outcome of brain SPECT assisted rTMS versus standard protocol of twenty sessions of high frequency rTMS as add on treatment in 20 patients with treatment resistant MDD, given over a period of 4 weeks. Thirteen subjects (group I) received high frequency rTMS over an area of hypoperfusion in the prefrontal cortex, as identified on SPECT, whereas 7 subjects (group II) were administered rTMS in the left dorsoslateral prefrontal cortex (DLPFC) area. Improvement was monitored using standardized instruments. Patients in the group I showed a significantly better response compared to those in the group II. In group I, 46% of the subjects were responders on MADRS, 38% on BDI and 77% on CGI. The parallel figures of responders in Group II were 0% on MADRS, 14% on BDI and 43% on CGI. There were no remitters in the study. No significant untoward side effects were noticed. The study had limitations of a small sample size and non-controlled design, and all the subjects were also receiving the standard antidepressant therapy. Administration of rTMS over brain SPECT specified area of hypoperfusion may have a better clinical outcome compared to the standard protocol.

  6. Resuscitation therapy for traumatic brain injury-induced coma in rats:mechanisms of median nerve electrical stimulation

    Institute of Scientific and Technical Information of China (English)

    Zhen Feng; Ying-jun Zhong; Liang Wang; Tian-qi Wei

    2015-01-01

    In this study, rats were put into traumatic brain injury-induced coma and treated with median nerve electrical stimulation. We explored the wake-promoting effect, and possible mechanisms, of median nerve electrical stimulation. Electrical stimulation upregulated the expression levels of orexin-A and its receptor OX1R in the rat prefrontal cortex. Orexin-A expression gradually in-creased with increasing stimulation, while OX1R expression reached a peak at 12 hours and then decreased. In addition, after the OX1R antagonist, SB334867, was injected into the brain of rats after traumatic brain injury, fewer rats were restored to consciousness, and orexin-A and OXIR expression in the prefrontal cortex was downregulated. Our ifndings indicate that median nerve electrical stimulation induced an up-regulation of orexin-A and OX1R expression in the pre-frontal cortex of traumatic brain injury-induced coma rats, which may be a potential mechanism involved in the wake-promoting effects of median nerve electrical stimulation.

  7. Resuscitation therapy for traumatic brain injury-induced coma in rats: mechanisms of median nerve electrical stimulation

    Directory of Open Access Journals (Sweden)

    Zhen Feng

    2015-01-01

    Full Text Available In this study, rats were put into traumatic brain injury-induced coma and treated with median nerve electrical stimulation. We explored the wake-promoting effect, and possible mechanisms, of median nerve electrical stimulation. Electrical stimulation upregulated the expression levels of orexin-A and its receptor OX1R in the rat prefrontal cortex. Orexin-A expression gradually increased with increasing stimulation, while OX1R expression reached a peak at 12 hours and then decreased. In addition, after the OX1R antagonist, SB334867, was injected into the brain of rats after traumatic brain injury, fewer rats were restored to consciousness, and orexin-A and OXIR expression in the prefrontal cortex was downregulated. Our findings indicate that median nerve electrical stimulation induced an up-regulation of orexin-A and OX1R expression in the prefrontal cortex of traumatic brain injury-induced coma rats, which may be a potential mechanism involved in the wake-promoting effects of median nerve electrical stimulation.

  8. When problem size matters: differential effects of brain stimulation on arithmetic problem solving and neural oscillations.

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    Bruno Rütsche

    Full Text Available The problem size effect is a well-established finding in arithmetic problem solving and is characterized by worse performance in problems with larger compared to smaller operand size. Solving small and large arithmetic problems has also been shown to involve different cognitive processes and distinct electroencephalography (EEG oscillations over the left posterior parietal cortex (LPPC. In this study, we aimed to provide further evidence for these dissociations by using transcranial direct current stimulation (tDCS. Participants underwent anodal (30min, 1.5 mA, LPPC and sham tDCS. After the stimulation, we recorded their neural activity using EEG while the participants solved small and large arithmetic problems. We found that the tDCS effects on performance and oscillatory activity critically depended on the problem size. While anodal tDCS improved response latencies in large arithmetic problems, it decreased solution rates in small arithmetic problems. Likewise, the lower-alpha desynchronization in large problems increased, whereas the theta synchronization in small problems decreased. These findings reveal that the LPPC is differentially involved in solving small and large arithmetic problems and demonstrate that the effects of brain stimulation strikingly differ depending on the involved neuro-cognitive processes.

  9. Nonmotor Symptoms and Subthalamic Deep Brain Stimulation in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Han-Joon Kim

    2015-05-01

    Full Text Available Subthalamic deep brain stimulation (STN DBS is an established treatment for the motor symptoms in patients with advanced Parkinson’s disease (PD. In addition to improvements in motor symptoms, many studies have reported changes in various nonmotor symptoms (NMSs after STN DBS in patients with PD. Psychiatric symptoms, including depression, apathy, anxiety, and impulsivity, can worsen or improve depending on the electrical stimulation parameters, the locations of the stimulating contacts within the STN, and changes in medications after surgery. Global cognitive function is not affected by STN DBS, and there is no increase in the incidence of dementia after STN DBS compared to that after medical treatment, although clinically insignificant declines in verbal