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neural implants

Zhizhong Wang, Xingyang Jiao, Songwei Wang, Xiaoke Niu, Li Shi
Reconstruction of visual input through a neuron response helps to understand the information processing mechanism of the visual system. This paper uses the amplitude and phase characteristics of the local field potential signal in the pigeon optic tectum area to reconstruct the visual input from the neuron response data by means of local information accumulation using a linear inverse filter and a back propagation neural network algorithm. The reconstructed results show that the correlation between three reconstructed images and their corresponding stimulus images (tree branches, birds, and eyeglasses) was 0...
June 15, 2018: Neuroreport
Wen-Ju Pan, Seung Yup Lee, Jacob Billings, Maysam Nezafati, Waqas Majeed, Erin Buckley, Shella Keilholz
Optical studies of ex vivo brain slices where blood is absent show that neural activity is accompanied by significant intrinsic optical signals (IOS) related to activity-dependent scattering changes in neural tissue. However, the neural scattering signals have been largely ignored in vivo in widely-used IOS methods where absorption contrast from hemoglobin was employed. Changes in scattering were observed on a time scale of seconds in previous brain slice IOS studies, similar to the time scale for the hemodynamic response...
June 13, 2018: NeuroImage
Brendon Wahlberg, Harmanvir Ghuman, Jessie R Liu, Michel Modo
Intracerebral implantation of cell suspensions is finding its clinical translation with encouraging results in patients with stroke. However, the survival of cells in the brain remains poor. Although the biological potential of neural stem cells (NSCs) is widely documented, the biomechanical effects of delivering cells through a syringe-needle remain poorly understood. We here detailed the biomechanical forces (pressure, shear stress) that cells are exposed to during ejection through different sized needles (20G, 26G, 32G) and syringes (10, 50, 250 µL) at relevant flow rates (1, 5, 10 µL/min)...
June 15, 2018: Scientific Reports
Jiayin Li, Xing Li, Zhifeng Xiao, Jianwu Dai
Spinal cord injury (SCI), especially the complete SCI, usually results in complete paralysis below the level of the injury and seriously affects the patient's quality of life. SCI repair is still a worldwide medical problem. In the last twenty years, Professor DAI Jianwu and his team pioneered complete SCI model by removing spinal tissue with varied lengths in rodents, canine, and non-human primates to verify therapeutic effect of different repair strategies. Moreover, they also started the first clinical study of functional collagen scaffold on patients with acute complete SCI on January 16th, 2015...
June 1, 2018: Chinese Journal of Reparative and Reconstructive Surgery
F Azizi, H R Jalil, Z Nasiri, J Moshtaghian, F Esmaeili, A Doostmohammadi, L Shabani, E Ebrahimie
Tissue engineering, as a novel transplantation therapy, aims to create biomaterial scaffolds resembling the extracellular matrix in order to regenerate the damaged tissues. Adding bioactive factors to the scaffold would improve cell-tissue interactions. In this study, the effect of chitosan poly vinyl alcohol nanofibers containing carbon nanotube scaffold with or without active bioglass (BG+ /BG- ), in combination with neonatal rat brain extract (NRBE) on cell viability, proliferation and neural differentiation of P19 embryonic carcinoma (EC) stem cells was investigated...
June 14, 2018: Journal of Tissue Engineering and Regenerative Medicine
Letizia Romeo, Francesca Diomede, Agnese Gugliandolo, Domenico Scionti, Fabrizio Lo Giudice, Veronica Lanza Cariccio, Renato Iori, Placido Bramanti, Oriana Trubiani, Emanuela Mazzon
The therapeutic strategies for neurodegenerative diseases still represent a vast research field because of the lack of targeted, effective and resolutive treatment for neurodegenerative diseases. The use of stem cell-based therapy is an alternative approach that could lead to the replacement of damaged neuronal tissue. For this purpose, adult mesenchymal stem cells (MSC), including periodontal ligament stem cells (PDLSCs), could be very useful for their differentiation capacity, easy isolation and the ability to perform an autologous implant...
June 14, 2018: Scientific Reports
Yang Gou, Danyan Liu, Jinfeng Liu, Hongran Sun
Bone mesenchymal stem cells (BMSCs) have been used worldwide to treat spinal cord injury, but their therapeutic mechanism is poorly understood. In this study, BMSCs were transplanted to aneurysm clip-injured rats to demonstrate their protective effect. We observed myelin sheaths through Luxol fast blue (LFB) staining, osmic acid staining, TUNEL and transmission electron microscopy (TEM). We performed Western blotting to analyze the expressions of brain-derived neurotrophic factor (BDNF) and caspase 3. BMSCs were transplanted at 1, 7 and 14 days after spinal cord injury...
May 25, 2018: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
Biswarup Ghosh, Zhicheng Wang, Jia Nong, Mark W Urban, Zhiling Zhang, Victoria A Trovillion, Megan C Wright, Yinghui Zhong, Angelo C Lepore
We developed an innovative biomaterial-based approach to repair the critical neural circuitry that controls diaphragm activation by locally delivering brain-derived neurotrophic factor (BDNF) to injured cervical spinal cord. BDNF can be used to restore respiratory function via a number of potential repair mechanisms; however, widespread BDNF biodistribution resulting from delivery methods such as systemic injection or lumbar puncture can lead to inefficient drug delivery and adverse side effects. As a viable alternative, we developed a novel hydrogel-based system loaded with polysaccharide-BDNF particles self-assembled by electrostatic interactions that can be safely implanted in the intrathecal space for achieving local BDNF delivery with controlled dosing and duration...
June 11, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
C Micheli, I M Schepers, M Ozker, D Yoshor, M S Beauchamp, J W Rieger
During natural speech perception, humans must parse temporally continuous auditory and visual speech signals into sequences of words. However, most studies of speech perception present only single words or syllables. We used electrocorticography (subdural electrodes implanted on the brains of epileptic patients) to investigate the neural mechanisms for processing continuous audiovisual speech signals consisting of individual sentences. Using partial correlation analysis, we found that posterior superior temporal gyrus (pSTG) and medial occipital cortex tracked both the auditory and visual speech envelopes...
June 11, 2018: European Journal of Neuroscience
Robert P Carlyon, Stefano Cosentino, John M Deeks, Wendy Parkinson, Julie A Arenberg
Previous psychophysical and modeling studies suggest that cathodic stimulation by a cochlear implant (CI) may preferentially activate the peripheral processes of the auditory nerve, whereas anodic stimulation may preferentially activate the central axons. Because neural degeneration typically starts with loss of the peripheral processes, lower thresholds for cathodic than for anodic stimulation may indicate good local neural survival. We measured thresholds for 99-pulse-per-second trains of triphasic (TP) pulses where the central high-amplitude phase was either anodic (TP-A) or cathodic (TP-C)...
June 7, 2018: Journal of the Association for Research in Otolaryngology: JARO
Yogesh Kishorkant Pithwa
STUDY DESIGN: Retrospective analysis of prospectively collected data. PURPOSE: To assess the relative advantages of implant constructs with and without pedicle screws in the concave apex for correcting scoliosis. OVERVIEW OF LITERATURE: Concave apical pedicles in scoliosis can be narrow and dysplastic. Neural structures also migrate toward concavity, leaving little room for error while inserting pedicle screws into the concave apex. METHODS: Patients (n=35) undergoing scoliosis surgery from September 2004 to September 2009 with minimum 5-year follow-up period were included...
June 2018: Asian Spine Journal
Majid Zamani, Dai Jiang, Andreas Demosthenous
There is a need for integrated spike sorting processors in implantable devices with low power consumption that have improved accuracy. Learning the characteristics of the variable input neural signals and adapting the functionality of the sorting process can improve the accuracy. An adaptive spike sorting processor is presented accounting for the variation in the input signal noise characteristics and the variable difficulty in the selection of the spike characteristics, which significantly improves the accuracy...
June 2018: IEEE Transactions on Biomedical Circuits and Systems
Adam Khalifa, Yasha Karimi, Qihong Wang, Sahithi Garikapati, Webert Montlouis, Milutin Stanacevic, Nitish Thakor, Ralph Etienne-Cummings
An implant that can electrically stimulate neurons across different depths and regions of the brain currently does not exist as it poses a number of obstacles that need to be solved. In order to address the challenges, this paper presents the concept of "microbead," a fully integrated wirelessly powered neural device that allows for spatially selective activation of neural tissue. The prototype chip is fabricated in 130-nm CMOS technology and currently measures 200 μm × 200 μm, which represents the smallest remotely powered stimulator to date...
June 2018: IEEE Transactions on Biomedical Circuits and Systems
Nerea Mangado, Jordi Pons-Prats, Martí Coma, Pavel Mistrík, Gemma Piella, Mario Ceresa, Miguel Á González Ballester
Cochlear implantation (CI) is a complex surgical procedure that restores hearing in patients with severe deafness. The successful outcome of the implanted device relies on a group of factors, some of them unpredictable or difficult to control. Uncertainties on the electrode array position and the electrical properties of the bone make it difficult to accurately compute the current propagation delivered by the implant and the resulting neural activation. In this context, we use uncertainty quantification methods to explore how these uncertainties propagate through all the stages of CI computational simulations...
2018: Frontiers in Physiology
Sebastien Delcasso, Sachira Denagamage, Zelie Britton, Ann M Graybiel
Understanding the neural mechanisms underlying human cognition and determining the causal factors for the development of brain pathologies are among the greatest challenges for society. Electrophysiological recordings offer remarkable observations of brain activity as they provide highly precise representations of information coding in both temporal and spatial domains. With the development of genetic tools over the last decades, mice have been a key model organism in neuroscience. However, conducting chronic in vivo electrophysiology in awake, behaving mice remains technically challenging, and this difficulty prevents many research teams from acquiring critical recordings in their mouse models...
2018: Frontiers in Neural Circuits
Zhifeng Xiao, Fengwu Tang, Yannan Zhao, Guang Han, Na Yin, Xing Li, Bing Chen, Sufang Han, Xianfeng Jiang, Chen Yun, Changyu Zhao, Shixiang Cheng, Sai Zhang, Jianwu Dai
Stem cells and biomaterials transplantation hold a promising treatment for functional recovery in spinal cord injury (SCI) animal models. However, the functional recovery of complete SCI patients was still a huge challenge in clinic. Additionally, there is no clinical standard procedure available to diagnose precisely an acute patient as complete SCI. Here, two acute SCI patients, with injury at thoracic 11 (T11) and cervical 4 (C4) level respectively, were judged as complete injury by a stricter method combined with American Spinal Injury Association (ASIA) Impairment Scale, magnetic resonance imaging (MRI) and nerve electrophysiology...
January 1, 2018: Cell Transplantation
Yanbo Zhang, Hengyong Yu
In the presence of metal implants, metal artifacts are introduced to x-ray computed tomography CT images. Although a large number of metal artifact reduction (MAR) methods have been proposed in the past decades, MAR is still one of the major problems in clinical x-ray CT. In this paper, we develop a convolutional neural network (CNN)-based open MAR framework, which fuses the information from the original and corrected images to suppress artifacts. The proposed approach consists of two phases. In the CNN training phase, we build a database consisting of metal-free, metal-inserted and pre-corrected CT images, and image patches are extracted and used for CNN training...
June 2018: IEEE Transactions on Medical Imaging
Lindsay DeVries, Julie G Arenberg
Speech understanding abilities vary widely among cochlear implant (CI) listeners. A potential source of this variability is the electrode-neuron interface (ENI), which includes peripheral factors such as electrode position and integrity of remaining spiral ganglion neurons. Suboptimal positioning of the electrode array has been associated with poorer speech outcomes; however, postoperative computerized tomography (CT) scans are often not available to clinicians. CT-estimated electrode-to-modiolus distance (distance from the inner wall of the cochlea) has been shown to account for some variability in behavioral thresholds...
June 4, 2018: Journal of the Association for Research in Otolaryngology: JARO
Catalina Vallejo-Giraldo, Katarzyna Krukiewicz, Ivo Calaresu, Jingyuan Zhu, Matteo Palma, Marc Fernandez-Yague, BenjaminW McDowell, Nathalia Peixoto, Nazar Farid, Gerard O'Connor, Laura Ballerini, Abhay Pandit, Manus Jonathan Paul Biggs
Following implantation, neuroelectrode functionality is susceptible to deterioration via reactive host cell response and glial scar-induced encapsulation. Within the neuroengineering community, there is a consensus that the induction of selective adhesion and regulated cellular interaction at the tissue-electrode interface can significantly enhance device interfacing and functionality in vivo. In particular, topographical modification holds promise for the development of functionalized neural interfaces to mediate initial cell adhesion and the subsequent evolution of gliosis, minimizing the onset of a proinflammatory glial phenotype, to provide long-term stability...
June 3, 2018: Small
Melanie Das, Sumihiro Maeda, Bozhong Hu, Gui-Qiu Yu, Weikun Guo, Isabel Lopez, Xinxing Yu, Chao Tai, Xin Wang, Lennart Mucke
Neural network dysfunction may contribute to functional decline and disease progression in neurodegenerative disorders. Diverse lines of evidence suggest that neuronal accumulation of tau promotes network dysfunction and cognitive decline. The A152T-variant of human tau (hTau-A152T) increases the risk of Alzheimer's disease (AD) and several other tauopathies. When overexpressed in neurons of transgenic mice, it causes age-dependent neuronal loss and cognitive decline, as well as non-convulsive epileptic activity, which is also seen in patients with AD...
May 31, 2018: Neurobiology of Disease
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