Functional Neurosurgery Unit

Tel Aviv, Israel

Functional Neurosurgery Unit

Tel Aviv, Israel

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Mukamel R.,University of California at Los Angeles | Ekstrom A.D.,University of California at Los Angeles | Ekstrom A.D.,University of California at Davis | Kaplan J.,University of California at Los Angeles | And 4 more authors.
Current Biology | Year: 2010

Direct recordings in monkeys have demonstrated that neurons in frontal and parietal areas discharge during execution and perception of actions [1-8]. Because these discharges "reflect" the perceptual aspects of actions of others onto the motor repertoire of the perceiver, these cells have been called mirror neurons. Their overlapping sensory-motor representations have been implicated in observational learning and imitation, two important forms of learning [9]. In humans, indirect measures of neural activity support the existence of sensory-motor mirroring mechanisms in homolog frontal and parietal areas [10, 11], other motor regions [12-15], and also the existence of multisensory mirroring mechanisms in nonmotor regions [16-19]. We recorded extracellular activity from 1177 cells in human medial frontal and temporal cortices while patients executed or observed hand grasping actions and facial emotional expressions. A significant proportion of neurons in supplementary motor area, and hippocampus and environs, responded to both observation and execution of these actions. A subset of these neurons demonstrated excitation during action-execution and inhibition during action-observation. These findings suggest that multiple systems in humans may be endowed with neural mechanisms of mirroring for both the integration and differentiation of perceptual and motor aspects of actions performed by self and others. © 2010 Elsevier Ltd. All rights reserved.

Georgiopoulos M.,Functional Neurosurgery Unit | Katsakiori P.,Functional Neurosurgery Unit | Kefalopoulou Z.,Functional Neurosurgery Unit | Constantoyannis C.,Functional Neurosurgery Unit
Stereotactic and Functional Neurosurgery | Year: 2010

Background/Aims: The purpose of the present article is a systematic review of the proposed medical or surgical treatments in patients in chronic vegetative state (VS) or minimally conscious state (MCS), as well as of their mechanisms of action and limitations. Methods: For this review, we have agreed to include patients in VS or MCS having persisted for over 6 months in posttraumatic cases, and over 3 months in nontraumatic cases, before the time of intervention. Searches were independently conducted by 2 investigators between May 2009 and September 2009 in the following databases: Medline, Web of Science and the Cochrane Library. The electronic search was complemented by cross-checking the references of all relevant articles. Overall, 16 papers were eligible for this systematic review. Results: According to the 16 eligible studies, medical management by dopaminergic agents (levodopa, amantadine), zolpidem and median nerve stimulation, or surgical management by deep brain stimulation, extradural cortical stimulation, spinal cord stimulation and intrathecal baclofen have shown to improve the level of consciousness in certain cases. Conclusion: The treatments proposed for disorders of consciousness have not yet gained the level of 'evidence-based treatments'; moreover, the studies to date have led to inconclusiveness. The published therapeutic responses must be substantiated by further clinical studies of sound methodology. Copyright © 2010 S. Karger AG.

Tankus A.,Technion - Israel Institute of Technology | Tankus A.,University of California at Los Angeles | Fried I.,University of California at Los Angeles | Fried I.,Functional Neurosurgery Unit | And 2 more authors.
Journal of Neural Engineering | Year: 2012

Brain-machine interfaces (BMIs) rely on decoding neuronal activity from a large number of electrodes. The implantation procedures, however, do not guarantee that all recorded units encode task-relevant information: selection of task-relevant neurons is critical to performance but is typically performed based on heuristics. Here, we describe an algorithm for decoding/classification of volitional actions from multiple spike trains, which automatically selects the relevant neurons. The method is based on sparse decomposition of the high-dimensional neuronal feature space, projecting it onto a low-dimensional space of codes serving as unique class labels. The new method is tested against a range of existing methods using simulations and recordings of the activity of 1592 neurons in 23 neurosurgical patients who performed motor or speech tasks. The parameter estimation algorithm is orders of magnitude faster than existing methods and achieves significantly higher accuracies for both simulations and human data, rendering sparse decoding highly attractive for BMIs. © 2012 IOP Publishing Ltd.

Cerf M.,California Institute of Technology | Cerf M.,University of California at Los Angeles | Cerf M.,New York University | Thiruvengadam N.,California Institute of Technology | And 11 more authors.
Nature | Year: 2010

Daily life continually confronts us with an exuberance of external, sensory stimuli competing with a rich stream of internal deliberations, plans and ruminations. The brain must select one or more of these for further processing. How this competition is resolved across multiple sensory and cognitive regions is not known; nor is it clear how internal thoughts and attention regulate this competition. Recording from single neurons in patients implanted with intracranial electrodes for clinical reasons, here we demonstrate that humans can regulate the activity of their neurons in the medial temporal lobe (MTL) to alter the outcome of the contest between external images and their internal representation. Subjects looked at a hybrid superposition of two images representing familiar individuals, landmarks, objects or animals and had to enhance one image at the expense of the other, competing one. Simultaneously, the spiking activity of their MTL neurons in different subregions and hemispheres was decoded in real time to control the content of the hybrid. Subjects reliably regulated, often on the first trial, the firing rate of their neurons, increasing the rate of some while simultaneously decreasing the rate of others. They did so by focusing onto one image, which gradually became clearer on the computer screen in front of their eyes, and thereby overriding sensory input. On the basis of the firing of these MTL neurons, the dynamics of the competition between visual images in the subject's mind was visualized on an external display. © 2010 Macmillan Publishers Limited. All rights reserved.

Tankus A.,University of California at Los Angeles | Tankus A.,Technion - Israel Institute of Technology | Fried I.,University of California at Los Angeles | Fried I.,Functional Neurosurgery Unit | And 2 more authors.
Nature Communications | Year: 2012

Human speech sounds are produced through a coordinated movement of structures along the vocal tract. Here we show highly structured neuronal encoding of vowel articulation. In medial-frontal neurons, we observe highly specific tuning to individual vowels, whereas superior temporal gyrus neurons have nonspecific, sinusoidally modulated tuning (analogous to motor cortical directional tuning). At the neuronal population level, a decoding analysis reveals that the underlying structure of vowel encoding reflects the anatomical basis of articulatory movements. This structured encoding enables accurate decoding of volitional speech segments and could be applied in the development of brain-machine interfaces for restoring speech in paralysed individuals. © 2012 Macmillan Publishers Limited. All rights reserved.

Tankus A.,Technion - Israel Institute of Technology | Tankus A.,Functional Neurosurgery Unit | Fried I.,Functional Neurosurgery Unit | Fried I.,University of California at Los Angeles | And 2 more authors.
Journal of Physiology Paris | Year: 2014

Brain-machine interfaces (BMIs) open new horizons for the treatment of paralyzed persons, giving hope for the artificial restoration of lost physiological functions. Whereas BMI development has mainly focused on motor rehabilitation, recent studies have suggested that higher cognitive functions can also be deciphered from brain activity, bypassing low level planning and execution functions, and replacing them by computer-controlled effectors. This review describes the new generation of cognitive-motor BMIs, focusing on three BMI types:. 1.Speech BMI - reconstructing a person's speech based on the neuronal activity.2.Direct object control - controlling object movement without mimicking the limb movement that would yield the desired object movement.3.Decoding internal processes, such as neuronal representations of sensory information and decision making.By outlining recent progress in developing these BMI types, we aim to provide a unified view of contemporary research towards the replacement of behavioral outputs of cognitive processes by direct interaction with the brain. © 2014.

Esposito F.,Maastricht University | Singer N.,Tel Aviv University | Singer N.,Wohl Institute for Advanced Imaging | Podlipsky I.,Wohl Institute for Advanced Imaging | And 7 more authors.
NeuroImage | Year: 2013

Linking regional metabolic changes with fluctuations in the local electromagnetic fields directly on the surface of the human cerebral cortex is of tremendous importance for a better understanding of detailed brain processes. Functional magnetic resonance imaging (fMRI) and intra-cranial electro-encephalography (iEEG) measure two technically unrelated but spatially and temporally complementary sets of functional descriptions of human brain activity. In order to allow fine-grained spatio-temporal human brain mapping at the population-level, an effective comparative framework for the cortex-based inter-subject analysis of iEEG and fMRI data sets is needed.We combined fMRI and iEEG recordings of the same patients with epilepsy during alternated intervals of passive movie viewing and music listening to explore the degree of local spatial correspondence and temporal coupling between blood oxygen level dependent (BOLD) fMRI changes and iEEG spectral power modulations across the cortical surface after cortex-based inter-subject alignment. To this purpose, we applied a simple model of the iEEG activity spread around each electrode location and the cortex-based inter-subject alignment procedure to transform discrete iEEG measurements into cortically distributed group patterns by establishing a fine anatomic correspondence of many iEEG cortical sites across multiple subjects.Our results demonstrate the feasibility of a multi-modal inter-subject cortex-based distributed analysis for combining iEEG and fMRI data sets acquired from multiple subjects with the same experimental paradigm but with different iEEG electrode coverage. The proposed iEEG-fMRI framework allows for improved group statistics in a common anatomical space and preserves the dynamic link between the temporal features of the two modalities. © 2012 Elsevier Inc.

Andelman F.,Functional Neurosurgery Unit | Hoofien D.,Hebrew University of Jerusalem | Goldberg I.,Tel Aviv Sourasky Medical Center | Aizenstein O.,Neuroradiology Unit | And 2 more authors.
Neurocase | Year: 2010

Mental time travel allows individuals to mentally project themselves backwards and forwards in subjective time. This case report describes a young woman suddenly rendered amnesic as a result of bilateral hippocampal damage following an epileptic seizure and brain anoxia. Her neuropsychological profile was characterized by a high-average general level of cognitive functioning, selective deficit in episodic memory of past events and a significant difficulty to envisage her personal future. This case provides clinical support for the concept of mental time travel with its retrospective and prospective components and for the hippocampus being its critical neural substrate. © 2010 Psychology Press.

Markaki E.,Functional Neurosurgery Unit | Kefalopoulou Z.,Functional Neurosurgery Unit | Georgiopoulos M.,Functional Neurosurgery Unit | Paschali A.,Functional Neurosurgery Unit | Constantoyannis C.,Functional Neurosurgery Unit
Clinical Neurology and Neurosurgery | Year: 2010

Background: Meige's syndrome is a rare form of segmental dystonia characterized by blepharospasm and oromandibular dystonia. Medical treatment including botulinum toxin injections usually present disappointing results. The experience on Deep Brain Stimulation (DBS) in the treatment of Meige's syndrome and other segmental dystonias is still limited. At the moment, only a few cases of pallidal DBS have been reported to improve this rare form of dystonia. Case description: We report on a case of a woman with a 7-year history of Meige's syndrome, which rendered her functionally blind. The treatment with botulinum toxin injections failed to improve her symptoms, whereas stereotactic bilateral DBS of the pallidum led to a dramatic clinical improvement. Clinical assessment using the Burke-Fahn-Mardsen Dystonia Rating Scale (BFMDRS) in a double-blind manner, showed an improvement of 70% in the Movement score and 93.33% in the Disability score (84% reduction of the total score) on the 3 and 6 month follow-up. Conclusions: Stereotactic pallidal DBS might be considered as a potential treatment in the management of Meige's syndrome. © 2009 Elsevier B.V. All rights reserved.

Sassi M.,Functional Neurosurgery Unit | Porta M.,Movement Disorders and Tourette Center | Servello D.,Functional Neurosurgery Unit
Acta Neurochirurgica | Year: 2011

Tourette's syndrome is a chronic neurobehavioral disorder that can demonstrate refractoriness to conservative treatments, or to invasive nonsurgical treatments such as botulinum toxin infiltration, or to psychobehavioral treatments. In these cases, the surgical option is often proposed, either with lesional interventions, or more recently with deep brain stimulation (DBS). This latter modality is currently preferred because of its reversibility and modularity. Some relevant issues, however, still persist in terms of appropriate indication to treatment, selection of target, and follow-up evaluation. © 2010 Springer-Verlag.

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