WorldWideScience

Sample records for brain visual prosthetics

  1. Brain activation during manipulation of the myoelectric prosthetic hand: a functional magnetic resonance imaging study.

    Science.gov (United States)

    Maruishi, Masaharu; Tanaka, Yoshiyuki; Muranaka, Hiroyuki; Tsuji, Toshio; Ozawa, Yoshiaki; Imaizumi, Satoshi; Miyatani, Makoto; Kawahara, Junichiro

    2004-04-01

    Neuroimaging data, particularly functional magnetic resonance imaging (fMRI) findings, have not been reported in users of the myoelectric or electromyographic (EMG) prosthetic hand. We developed a virtual EMG prosthetic hand system to eliminate mutual signal noise interference between fMRI imaging and the EMG prosthesis. We used fMRI to localize activation in the human brain during manipulation of the virtual EMG prosthetic hand. Fourteen right-handed normal subjects were instructed to perform repetitive grasping with the right hand with eyes closed (CEG); repetitive grasping with the right hand with eyes open to obtain visual feedback of their own hand movement (OEG); and repetitive grasping with the virtual EMG prosthetic hand with the eyes open to obtain visual feedback of the prosthetic hand movement (VRG). The specific site activated during manipulation of the EMG prosthetic hand was the right ventral premotor cortex. Both paradigms with visual feedback also (OEG and VRG) demonstrated activation in the right posterior parietal cortex. The center of activation of the right posterior parietal cortex shifted laterally for visual feedback with the virtual EMG prosthetic hand compared to a subject's own hand. The results suggest that the EMG prosthetic hand might be recognized in the brain as a high-performance alternative to a real hand, being controlled through a "mirror system" in the brain.

  2. 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.

  3. Attaining higher resolution visual prosthetics: a review of the factors and limitations

    Science.gov (United States)

    Eiber, Calvin D.; Lovell, Nigel H.; Suaning, Gregg J.

    2013-02-01

    Visual prosthetics is an expanding subfield of functional electrical stimulation which has gained increased interest recently in light of new advances in treatments and technology. These treatments and technology represent a major improvement over prior art, but are still subject to a host of limitations which are dependent on the manner in which one approaches the topic of visual prosthetics. These limitations pose new research challenges whose solutions are directly applicable to the well-being of blind individuals everywhere. In this review, we will outline and critically compare major current approaches to visual prosthetics, and in particular retinal prosthetics. Then, we will engage in an in-depth discussion of the limitations imposed by current technology, physics, and the underlying biology of the retina to highlight several of the challenges currently facing researchers. .

  4. Image Processing Strategies Based on a Visual Saliency Model for Object Recognition Under Simulated Prosthetic Vision.

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    Wang, Jing; Li, Heng; Fu, Weizhen; Chen, Yao; Li, Liming; Lyu, Qing; Han, Tingting; Chai, Xinyu

    2016-01-01

    Retinal prostheses have the potential to restore partial vision. Object recognition in scenes of daily life is one of the essential tasks for implant wearers. Still limited by the low-resolution visual percepts provided by retinal prostheses, it is important to investigate and apply image processing methods to convey more useful visual information to the wearers. We proposed two image processing strategies based on Itti's visual saliency map, region of interest (ROI) extraction, and image segmentation. Itti's saliency model generated a saliency map from the original image, in which salient regions were grouped into ROI by the fuzzy c-means clustering. Then Grabcut generated a proto-object from the ROI labeled image which was recombined with background and enhanced in two ways--8-4 separated pixelization (8-4 SP) and background edge extraction (BEE). Results showed that both 8-4 SP and BEE had significantly higher recognition accuracy in comparison with direct pixelization (DP). Each saliency-based image processing strategy was subject to the performance of image segmentation. Under good and perfect segmentation conditions, BEE and 8-4 SP obtained noticeably higher recognition accuracy than DP, and under bad segmentation condition, only BEE boosted the performance. The application of saliency-based image processing strategies was verified to be beneficial to object recognition in daily scenes under simulated prosthetic vision. They are hoped to help the development of the image processing module for future retinal prostheses, and thus provide more benefit for the patients.

  5. Head mounted DMD based projection system for natural and prosthetic visual stimulation in freely moving rats

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    Arens-Arad, Tamar; Farah, Nairouz; Ben-Yaish, Shai; Zlotnik, Alex; Zalevsky, Zeev; Mandel, Yossi

    2016-01-01

    Novel technologies are constantly under development for vision restoration in blind patients. Many of these emerging technologies are based on the projection of high intensity light patterns at specific wavelengths, raising the need for the development of specialized projection systems. Here we present and characterize a novel projection system that meets the requirements for artificial retinal stimulation in rats and enables the recording of cortical responses. The system is based on a customized miniature Digital Mirror Device (DMD) for pattern projection, in both visible (525 nm) and NIR (915 nm) wavelengths, and a lens periscope for relaying the pattern directly onto the animal’s retina. Thorough system characterization and the investigation of the effect of various parameters on obtained image quality were performed using ZEMAX. Simulation results revealed that images with an MTF higher than 0.8 were obtained with little effect of the vertex distance. Increased image quality was obtained at an optimal pupil diameter and smaller field of view. Visual cortex activity data was recorded simultaneously with pattern projection, further highlighting the importance of the system for prosthetic vision studies. This novel head mounted projection system may prove to be a vital tool in studying natural and artificial vision in behaving animals. PMID:27731346

  6. Head mounted DMD based projection system for natural and prosthetic visual stimulation in freely moving rats

    Science.gov (United States)

    Arens-Arad, Tamar; Farah, Nairouz; Ben-Yaish, Shai; Zlotnik, Alex; Zalevsky, Zeev; Mandel, Yossi

    2016-10-01

    Novel technologies are constantly under development for vision restoration in blind patients. Many of these emerging technologies are based on the projection of high intensity light patterns at specific wavelengths, raising the need for the development of specialized projection systems. Here we present and characterize a novel projection system that meets the requirements for artificial retinal stimulation in rats and enables the recording of cortical responses. The system is based on a customized miniature Digital Mirror Device (DMD) for pattern projection, in both visible (525 nm) and NIR (915 nm) wavelengths, and a lens periscope for relaying the pattern directly onto the animal’s retina. Thorough system characterization and the investigation of the effect of various parameters on obtained image quality were performed using ZEMAX. Simulation results revealed that images with an MTF higher than 0.8 were obtained with little effect of the vertex distance. Increased image quality was obtained at an optimal pupil diameter and smaller field of view. Visual cortex activity data was recorded simultaneously with pattern projection, further highlighting the importance of the system for prosthetic vision studies. This novel head mounted projection system may prove to be a vital tool in studying natural and artificial vision in behaving animals.

  7. 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.

  8. Visual artistic creativity and the brain.

    Science.gov (United States)

    Heilman, Kenneth M; Acosta, Lealani Mae

    2013-01-01

    Creativity is the development of a new or novel understanding--insight that leads to the expression of orderly relationships (e.g., finding and revealing the thread that unites). Visual artistic creativity plays an important role in the quality of human lives, and the goal of this chapter is to describe some of the brain mechanisms that may be important in visual artistic creativity. The initial major means of learning how the brain mediates any activity is to understand the anatomy and physiology that may support these processes. A further understanding of specific cognitive activities and behaviors may be gained by studying patients who have diseases of the brain and how these diseases influence these functions. Physiological recording such as electroencephalography and brain imaging techniques such as PET and fMRI have also allowed us to gain a better understanding of the brain mechanisms important in visual creativity. In this chapter, we discuss anatomic and physiological studies, as well as neuropsychological studies of healthy artists and patients with neurological disease that have helped us gain some insight into the brain mechanisms that mediate artistic creativity.

  9. Prosthetic Engineering

    Science.gov (United States)

    ... Overview CoE for Limb Loss Prevention and Prosthetic Engineering Menu Menu VA Center of Excellence for Limb ... ZIP code here Enter ZIP code here Prosthetic Engineering - Overview Our aim is to improve prosthetic prescription ...

  10. Brain Activity in Response to Visual Symmetry

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    Marco Bertamini

    2014-12-01

    Full Text Available A number of studies have explored visual symmetry processing by measuring event related potentials and neural oscillatory activity. There is a sustained posterior negativity (SPN related to the presence of symmetry. There is also functional magnetic resonance imaging (MRI activity in extrastriate visual areas and in the lateral occipital complex. We summarise the evidence by answering six questions. (1 Is there an automatic and sustained response to symmetry in visual areas? Answer: Yes, and this suggests automatic processing of symmetry. (2 Which brain areas are involved in symmetry perception? Answer: There is an extended network from extrastriate areas to higher areas. (3 Is reflection special? Answer: Reflection is the optimal stimulus for a more general regularity-sensitive network. (4 Is the response to symmetry independent of view angle? Answer: When people classify patterns as symmetrical or random, the response to symmetry is view-invariant. When people attend to other dimensions, the network responds to residual regularity in the image. (5 How are brain rhythms in the two hemispheres altered during symmetry perception? Answer: Symmetry processing (rather than presence produces more alpha desynchronization in the right posterior regions. Finally, (6 does symmetry processing produce positive affect? Answer: Not in the strongest sense, but behavioural measures reveal implicit positive evaluation of abstract symmetry.

  11. Visualizing the blind brain: brain imaging of visual field defects from early recovery to rehabilitation techniques

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    Marika eUrbanski

    2014-09-01

    Full Text Available Visual field defects (VFDs are one of the most common consequences observed after brain injury, especially after a stroke in the posterior cerebral artery territory. Less frequently, tumours, traumatic brain injury, brain surgery or demyelination can also determine various visual disabilities, from a decrease in visual acuity to cerebral blindness. VFD is a factor of bad functional prognosis as it compromises many daily life activities (e.g., obstacle avoidance, driving, and reading and therefore the patient’s quality of life. Spontaneous recovery seems to be limited and restricted to the first six months, with the best chance of improvement at one month. The possible mechanisms at work could be partly due to cortical reorganization in the visual areas (plasticity and/or partly to the use of intact alternative visual routes, first identified in animal studies and possibly underlying the phenomenon of blindsight. Despite processes of early recovery, which is rarely complete, and learning of compensatory strategies, the patient’s autonomy may still be compromised at more chronic stages. Therefore, various rehabilitation therapies based on neuroanatomical knowledge have been developed to improve VFDs. These use eye-movement training techniques (e.g., visual search, saccadic eye movements, reading training, visual field restitution (the Vision Restoration Therapy, VRT, or perceptual learning. In this review, we will focus on studies of human adults with acquired VFDs, which have used different imaging techniques (Positron Emission Tomography: PET, Diffusion Tensor Imaging: DTI, functional Magnetic Resonance Imaging: fMRI, MagnetoEncephalography: MEG or neurostimulation techniques (Transcranial Magnetic Stimulation: TMS; transcranial Direct Current Stimulation, tDCS to show brain activations in the course of spontaneous recovery or after specific rehabilitation techniques.

  12. Psychophysical testing of visual prosthetic devices: a call to establish a multi-national joint task force

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    Rizzo, Joseph F., III; Ayton, Lauren N.

    2014-04-01

    Recent advances in the field of visual prostheses, as showcased in this special feature of Journal of Neural Engineering , have led to promising results from clinical trials of a number of devices. However, as noted by these groups there are many challenges involved in assessing vision of people with profound vision loss. As such, it is important that there is consistency in the methodology and reporting standards for clinical trials of visual prostheses and, indeed, the broader vision restoration research field. Two visual prosthesis research groups, the Boston Retinal Implant Project (BRIP) and Bionic Vision Australia (BVA), have agreed to work cooperatively to establish a multi-national Joint Task Force. The aim of this Task Force will be to develop a consensus statement to guide the methods used to conduct and report psychophysical and clinical results of humans who receive visual prosthetic devices. The overarching goal is to ensure maximum benefit to the implant recipients, not only in the outcomes of the visual prosthesis itself, but also in enabling them to obtain accurate information about this research with ease. The aspiration to develop a Joint Task Force was first promulgated at the inaugural 'The Eye and the Chip' meeting in September 2000. This meeting was established to promote the development of the visual prosthetic field by applying the principles of inclusiveness, openness, and collegiality among the growing body of researchers in this field. These same principles underlie the intent of this Joint Task Force to enhance the quality of psychophysical research within our community. Despite prior efforts, a critical mass of interested parties could not congeal. Renewed interest for developing joint guidelines has developed recently because of a growing awareness of the challenges of obtaining reliable measurements of visual function in patients who are severely visually impaired (in whom testing is inherently noisy), and of the importance of

  13. Viability of Controlling Prosthetic Hand Utilizing Electroencephalograph (EEG) Dataset Signal

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    Miskon, Azizi; A/L Thanakodi, Suresh; Raihan Mazlan, Mohd; Mohd Haziq Azhar, Satria; Nooraya Mohd Tawil, Siti

    2016-11-01

    This project presents the development of an artificial hand controlled by Electroencephalograph (EEG) signal datasets for the prosthetic application. The EEG signal datasets were used as to improvise the way to control the prosthetic hand compared to the Electromyograph (EMG). The EMG has disadvantages to a person, who has not used the muscle for a long time and also to person with degenerative issues due to age factor. Thus, the EEG datasets found to be an alternative for EMG. The datasets used in this work were taken from Brain Computer Interface (BCI) Project. The datasets were already classified for open, close and combined movement operations. It served the purpose as an input to control the prosthetic hand by using an Interface system between Microsoft Visual Studio and Arduino. The obtained results reveal the prosthetic hand to be more efficient and faster in response to the EEG datasets with an additional LiPo (Lithium Polymer) battery attached to the prosthetic. Some limitations were also identified in terms of the hand movements, weight of the prosthetic, and the suggestions to improve were concluded in this paper. Overall, the objective of this paper were achieved when the prosthetic hand found to be feasible in operation utilizing the EEG datasets.

  14. Prosthetic Feet

    Science.gov (United States)

    ... us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Prosthetic Feet Translated into plain language by Helen Osborne ... Dupes There are more than 50 models of prosthetic feet available today. Some are designed for special ...

  15. Restoring the sense of touch with a prosthetic hand through a brain interface.

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    Tabot, Gregg A; Dammann, John F; Berg, Joshua A; Tenore, Francesco V; Boback, Jessica L; Vogelstein, R Jacob; Bensmaia, Sliman J

    2013-11-05

    Our ability to manipulate objects dexterously relies fundamentally on sensory signals originating from the hand. To restore motor function with upper-limb neuroprostheses requires that somatosensory feedback be provided to the tetraplegic patient or amputee. Given the complexity of state-of-the-art prosthetic limbs and, thus, the huge state space they can traverse, it is desirable to minimize the need for the patient to learn associations between events impinging on the limb and arbitrary sensations. Accordingly, we have developed approaches to intuitively convey sensory information that is critical for object manipulation--information about contact location, pressure, and timing--through intracortical microstimulation of primary somatosensory cortex. In experiments with nonhuman primates, we show that we can elicit percepts that are projected to a localized patch of skin and that track the pressure exerted on the skin. In a real-time application, we demonstrate that animals can perform a tactile discrimination task equally well whether mechanical stimuli are delivered to their native fingers or to a prosthetic one. Finally, we propose that the timing of contact events can be signaled through phasic intracortical microstimulation at the onset and offset of object contact that mimics the ubiquitous on and off responses observed in primary somatosensory cortex to complement slowly varying pressure-related feedback. We anticipate that the proposed biomimetic feedback will considerably increase the dexterity and embodiment of upper-limb neuroprostheses and will constitute an important step in restoring touch to individuals who have lost it.

  16. Fluorescent Nanoparticle Uptake for Brain Tumor Visualization

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    Rachel Tréhin

    2006-04-01

    Full Text Available Accurate delineation of tumor margins is vital to the successful surgical resection of brain tumors. We have previously developed a multimodal nanoparticle CLIO-Cy5.5, which is detectable by both magnetic resonance imaging and fluorescence, to assist in intraoperatively visualizing tumor boundaries. Here we examined the accuracy of tumor margin determination of orthotopic tumors implanted in hosts with differing immune responses to the tumor. Using a nonuser-based signal intensity method applied to fluorescent micrographs of 9L gliosarcoma green fluorescent protein (GFP tumors, mean overestimations of 2 and 24 µm were obtained using Cy5.5 fluorescence, compared to the true tumor margin determined by GFP fluorescence, in nude mice and rats, respectively. To resolve which cells internalized the nanoparticle and to quantitate degree of uptake, tumors were disaggregated and cells were analyzed by flow cytometry and fluorescence microscopy. Nanoparticle uptake was seen in both CD11b+ cells (representing activated microglia and macrophages and tumor cells in both animal models by both methods. CD11b+ cells were predominantly found at the tumor margin in both hosts, but were more pronounced at the margin in the rat model. Additional metastatic (CT26 colon and primary (Gli36 glioma brain tumor models likewise demonstrated that the nanoparticle was internalized both by tumor cells and by host cells. Together, these observations suggest that fluorescent nanoparticles provide an accurate method of tumor margin estimation based on a combination of tumor cell and host cell uptake for primary and metastatic tumors in animal model systems and offer potential for clinical translation.

  17. Visual dictionaries as intermediate features in the human brain

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    Kandan eRamakrishnan

    2015-01-01

    Full Text Available The human visual system is assumed to transform low level visual features to object and scene representations via features of intermediate complexity. How the brain computationally represents intermediate features is still unclear. To further elucidate this, we compared the biologically plausible HMAX model and Bag of Words (BoW model from computer vision. Both these computational models use visual dictionaries, candidate features of intermediate complexity, to represent visual scenes, and the models have been proven effective in automatic object and scene recognition. These models however differ in the computation of visual dictionaries and pooling techniques. We investigated where in the brain and to what extent human fMRI responses to short video can be accounted for by multiple hierarchical levels of the HMAX and BoW models. Brain activity of 20 subjects obtained while viewing a short video clip was analyzed voxel-wise using a distance-based variation partitioning method. Results revealed that both HMAX and BoW explain a significant amount of brain activity in early visual regions V1, V2 and V3. However BoW exhibits more consistency across subjects in accounting for brain activity compared to HMAX. Furthermore, visual dictionary representations by HMAX and BoW explain significantly some brain activity in higher areas which are believed to process intermediate features. Overall our results indicate that, although both HMAX and BoW account for activity in the human visual system, the BoW seems to more faithfully represent neural responses in low and intermediate level visual areas of the brain.

  18. Shared visual attention and memory systems in the Drosophila brain.

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    Bruno van Swinderen

    Full Text Available BACKGROUND: Selective attention and memory seem to be related in human experience. This appears to be the case as well in simple model organisms such as the fly Drosophila melanogaster. Mutations affecting olfactory and visual memory formation in Drosophila, such as in dunce and rutabaga, also affect short-term visual processes relevant to selective attention. In particular, increased optomotor responsiveness appears to be predictive of visual attention defects in these mutants. METHODOLOGY/PRINCIPAL FINDINGS: To further explore the possible overlap between memory and visual attention systems in the fly brain, we screened a panel of 36 olfactory long term memory (LTM mutants for visual attention-like defects using an optomotor maze paradigm. Three of these mutants yielded high dunce-like optomotor responsiveness. We characterized these three strains by examining their visual distraction in the maze, their visual learning capabilities, and their brain activity responses to visual novelty. We found that one of these mutants, D0067, was almost completely identical to dunce(1 for all measures, while another, D0264, was more like wild type. Exploiting the fact that the LTM mutants are also Gal4 enhancer traps, we explored the sufficiency for the cells subserved by these elements to rescue dunce attention defects and found overlap at the level of the mushroom bodies. Finally, we demonstrate that control of synaptic function in these Gal4 expressing cells specifically modulates a 20-30 Hz local field potential associated with attention-like effects in the fly brain. CONCLUSIONS/SIGNIFICANCE: Our study uncovers genetic and neuroanatomical systems in the fly brain affecting both visual attention and odor memory phenotypes. A common component to these systems appears to be the mushroom bodies, brain structures which have been traditionally associated with odor learning but which we propose might be also involved in generating oscillatory brain activity

  19. Visual dictionaries as intermediate features in the human brain.

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    Ramakrishnan, Kandan; Scholte, H Steven; Groen, Iris I A; Smeulders, Arnold W M; Ghebreab, Sennay

    2014-01-01

    The human visual system is assumed to transform low level visual features to object and scene representations via features of intermediate complexity. How the brain computationally represents intermediate features is still unclear. To further elucidate this, we compared the biologically plausible HMAX model and Bag of Words (BoW) model from computer vision. Both these computational models use visual dictionaries, candidate features of intermediate complexity, to represent visual scenes, and the models have been proven effective in automatic object and scene recognition. These models however differ in the computation of visual dictionaries and pooling techniques. We investigated where in the brain and to what extent human fMRI responses to short video can be accounted for by multiple hierarchical levels of the HMAX and BoW models. Brain activity of 20 subjects obtained while viewing a short video clip was analyzed voxel-wise using a distance-based variation partitioning method. Results revealed that both HMAX and BoW explain a significant amount of brain activity in early visual regions V1, V2, and V3. However, BoW exhibits more consistency across subjects in accounting for brain activity compared to HMAX. Furthermore, visual dictionary representations by HMAX and BoW explain significantly some brain activity in higher areas which are believed to process intermediate features. Overall our results indicate that, although both HMAX and BoW account for activity in the human visual system, the BoW seems to more faithfully represent neural responses in low and intermediate level visual areas of the brain.

  20. Visual dictionaries as intermediate features in the human brain

    NARCIS (Netherlands)

    K. Ramakrishnan; H.S. Scholte; I.I.A. Groen; A.W.M. Smeulders; S. Ghebreab

    2015-01-01

    The human visual system is assumed to transform low level visual features to object and scene representations via features of intermediate complexity. How the brain computationally represents intermediate features is still unclear. To further elucidate this, we compared the biologically plausible HM

  1. Dynamic Data Visualization with Weave and Brain Choropleths.

    Directory of Open Access Journals (Sweden)

    Dianne Patterson

    Full Text Available This article introduces the neuroimaging community to the dynamic visualization workbench, Weave (https://www.oicweave.org/, and a set of enhancements to allow the visualization of brain maps. The enhancements comprise a set of brain choropleths and the ability to display these as stacked slices, accessible with a slider. For the first time, this allows the neuroimaging community to take advantage of the advanced tools already available for exploring geographic data. Our brain choropleths are modeled after widely used geographic maps but this mashup of brain choropleths with extant visualization software fills an important neuroinformatic niche. To date, most neuroinformatic tools have provided online databases and atlases of the brain, but not good ways to display the related data (e.g., behavioral, genetic, medical, etc. The extension of the choropleth to brain maps allows us to leverage general-purpose visualization tools for concurrent exploration of brain images and related data. Related data can be represented as a variety of tables, charts and graphs that are dynamically linked to each other and to the brain choropleths. We demonstrate that the simplified region-based analyses that underlay choropleths can provide insights into neuroimaging data comparable to those achieved by using more conventional methods. In addition, the interactive interface facilitates additional insights by allowing the user to filter, compare, and drill down into the visual representations of the data. This enhanced data visualization capability is useful during the initial phases of data analysis and the resulting visualizations provide a compelling way to publish data as an online supplement to journal articles.

  2. Review of Brain-Machine Interfaces Used in Neural Prosthetics with New Perspective on Somatosensory Feedback through Method of Signal Breakdown.

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    Vidal, Gabriel W Vattendahl; Rynes, Mathew L; Kelliher, Zachary; Goodwin, Shikha Jain

    2016-01-01

    The brain-machine interface (BMI) used in neural prosthetics involves recording signals from neuron populations, decoding those signals using mathematical modeling algorithms, and translating the intended action into physical limb movement. Recently, somatosensory feedback has become the focus of many research groups given its ability in increased neural control by the patient and to provide a more natural sensation for the prosthetics. This process involves recording data from force sensitive locations on the prosthetics and encoding these signals to be sent to the brain in the form of electrical stimulation. Tactile sensation has been achieved through peripheral nerve stimulation and direct stimulation of the somatosensory cortex using intracortical microstimulation (ICMS). The initial focus of this paper is to review these principles and link them to modern day applications such as restoring limb use to those who lack such control. With regard to how far the research has come, a new perspective for the signal breakdown concludes the paper, offering ideas for more real somatosensory feedback using ICMS to stimulate particular sensations by differentiating touch sensors and filtering data based on unique frequencies.

  3. Decoding brain responses to pixelized images in the primary visual cortex: implications for visual cortical prostheses.

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    Guo, Bing-Bing; Zheng, Xiao-Lin; Lu, Zhen-Gang; Wang, Xing; Yin, Zheng-Qin; Hou, Wen-Sheng; Meng, Ming

    2015-10-01

    Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only "see" pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex (the implant area) is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine (LSVM) as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.

  4. Linking brain imaging signals to visual perception.

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    Welchman, Andrew E; Kourtzi, Zoe

    2013-11-01

    The rapid advances in brain imaging technology over the past 20 years are affording new insights into cortical processing hierarchies in the human brain. These new data provide a complementary front in seeking to understand the links between perceptual and physiological states. Here we review some of the challenges associated with incorporating brain imaging data into such "linking hypotheses," highlighting some of the considerations needed in brain imaging data acquisition and analysis. We discuss work that has sought to link human brain imaging signals to existing electrophysiological data and opened up new opportunities in studying the neural basis of complex perceptual judgments. We consider a range of approaches when using human functional magnetic resonance imaging to identify brain circuits whose activity changes in a similar manner to perceptual judgments and illustrate these approaches by discussing work that has studied the neural basis of 3D perception and perceptual learning. Finally, we describe approaches that have sought to understand the information content of brain imaging data using machine learning and work that has integrated multimodal data to overcome the limitations associated with individual brain imaging approaches. Together these approaches provide an important route in seeking to understand the links between physiological and psychological states.

  5. BrainBrowser: distributed, web-based neurological data visualization.

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    Sherif, Tarek; Kassis, Nicolas; Rousseau, Marc-Étienne; Adalat, Reza; Evans, Alan C

    2014-01-01

    Recent years have seen massive, distributed datasets become the norm in neuroimaging research, and the methodologies used to analyze them have, in response, become more collaborative and exploratory. Tools and infrastructure are continuously being developed and deployed to facilitate research in this context: grid computation platforms to process the data, distributed data stores to house and share them, high-speed networks to move them around and collaborative, often web-based, platforms to provide access to and sometimes manage the entire system. BrainBrowser is a lightweight, high-performance JavaScript visualization library built to provide easy-to-use, powerful, on-demand visualization of remote datasets in this new research environment. BrainBrowser leverages modern web technologies, such as WebGL, HTML5 and Web Workers, to visualize 3D surface and volumetric neuroimaging data in any modern web browser without requiring any browser plugins. It is thus trivial to integrate BrainBrowser into any web-based platform. BrainBrowser is simple enough to produce a basic web-based visualization in a few lines of code, while at the same time being robust enough to create full-featured visualization applications. BrainBrowser can dynamically load the data required for a given visualization, so no network bandwidth needs to be waisted on data that will not be used. BrainBrowser's integration into the standardized web platform also allows users to consider using 3D data visualization in novel ways, such as for data distribution, data sharing and dynamic online publications. BrainBrowser is already being used in two major online platforms, CBRAIN and LORIS, and has been used to make the 1TB MACACC dataset openly accessible.

  6. BrainBrowser: distributed, web-based neurological data visualization

    Directory of Open Access Journals (Sweden)

    Tarek eSherif

    2015-01-01

    Full Text Available Recent years have seen massive, distributed datasets become the norm in neuroimaging research, and the methodologies used analyze them have, in response, become more collaborative and exploratory. Tools and infrastructure are continuously being developed and deployed to facilitate research in this context: grid computation platforms to process the data, distributed data stores to house and share them, high-speed networks to move them around and collaborative, often web-based, platforms to provide access to and sometimes manage the entire system. BrainBrowser is a lightweight, high-performance JavaScript visualization library built to provide easy-to-use, powerful, on-demand visualization of remote datasets in this new research environment. BrainBrowser leverages modern Web technologies, such as WebGL, HTML5 and Web Workers, to visualize 3D surface and volumetric neuroimaging data in any modern web browser without requiring any browser plugins. It is thus trivial to integrate BrainBrowser into any web-based platform. BrainBrowser is simple enough to produce a basic web-based visualization in a few lines of code, while at the same time being robust enough to create full-featured visualization applications. BrainBrowser can dynamically load the data required for a given visualization, so no network bandwidth needs to be waisted on data that will not be used. BrainBrowser's integration into the standardized web platform also allows users to consider using 3D data visualization in novel ways, such as for data distribution, data sharing and dynamic online publications. BrainBrowser is already being used in two major online platforms, CBRAIN and LORIS, and has been used to make the 1TB MACACC dataset openly accessible.

  7. Electroretinography and Visual Evoked Potentials in Childhood Brain Tumor Survivors.

    Science.gov (United States)

    Pietilä, Sari; Lenko, Hanna L; Oja, Sakari; Koivisto, Anna-Maija; Pietilä, Timo; Mäkipernaa, Anne

    2016-07-01

    This population-based cross-sectional study evaluates the clinical value of electroretinography and visual evoked potentials in childhood brain tumor survivors. A flash electroretinography and a checkerboard reversal pattern visual evoked potential (or alternatively a flash visual evoked potential) were done for 51 survivors (age 3.8-28.7 years) after a mean follow-up time of 7.6 (1.5-15.1) years. Abnormal electroretinography was obtained in 1 case, bilaterally delayed abnormal visual evoked potentials in 22/51 (43%) cases. Nine of 25 patients with infratentorial tumor location, and altogether 12 out of 31 (39%) patients who did not have tumors involving the visual pathways, had abnormal visual evoked potentials. Abnormal electroretinographies are rarely observed, but abnormal visual evoked potentials are common even without evident anatomic lesions in the visual pathway. Bilateral changes suggest a general and possibly multifactorial toxic/adverse effect on the visual pathway. Electroretinography and visual evoked potential may have clinical and scientific value while evaluating long-term effects of childhood brain tumors and tumor treatment.

  8. Visual field restorative rehabilitation after brain injury.

    Science.gov (United States)

    Matteo, Barbara Maria; Viganò, Barbara; Cerri, Cesare Giuseppe; Perin, Cecilia

    2016-07-01

    About 20%-30% of patients undergoing neurological rehabilitation report visual field defects, one of the most frequent of which is homonymous hemianopsia (loss of the same half of the visual field in both eyes). There is still no consensus as to whether homonymous hemianopsia is best treated in a restorative or compensatory manner. The aim of this review is to describe the effects of restorative rehabilitation, whose long-term efficacy is still being debated. We analyzed 56 articles describing the use of various techniques used to promote visual field recovery but concentrating on two approaches: "border training," which involves exercising vision at the edge of the damaged visual field, and "blindsight training," which is based on exercising unconscious perceptual functions in the mild of the blind hemifield where the scotoma is deep. Both techniques have been supported by functional imaging studies showing evidence of cortical rearrangement (plasticity) after rehabilitation. Although no formal meta-analysis was possible, the results of a semiquantitative evaluation suggested that the improvement in visual skills obtained is related to the type of training used: Border rehabilitation seems to improve the detection of visual stimuli, whereas blindsight rehabilitation seems to improve their processing. Finally, the addition of transcranial direct current stimulation seems to enhance the effects of visual field rehabilitation.

  9. Visual and audiovisual effects of isochronous timing on visual perception and brain activity.

    Science.gov (United States)

    Marchant, Jennifer L; Driver, Jon

    2013-06-01

    Understanding how the brain extracts and combines temporal structure (rhythm) information from events presented to different senses remains unresolved. Many neuroimaging beat perception studies have focused on the auditory domain and show the presence of a highly regular beat (isochrony) in "auditory" stimulus streams enhances neural responses in a distributed brain network and affects perceptual performance. Here, we acquired functional magnetic resonance imaging (fMRI) measurements of brain activity while healthy human participants performed a visual task on isochronous versus randomly timed "visual" streams, with or without concurrent task-irrelevant sounds. We found that visual detection of higher intensity oddball targets was better for isochronous than randomly timed streams, extending previous auditory findings to vision. The impact of isochrony on visual target sensitivity correlated positively with fMRI signal changes not only in visual cortex but also in auditory sensory cortex during audiovisual presentations. Visual isochrony activated a similar timing-related brain network to that previously found primarily in auditory beat perception work. Finally, activity in multisensory left posterior superior temporal sulcus increased specifically during concurrent isochronous audiovisual presentations. These results indicate that regular isochronous timing can modulate visual processing and this can also involve multisensory audiovisual brain mechanisms.

  10. Allen Brain Atlas-Driven Visualizations: A Web-Based Gene Expression Energy Visualization Tool

    Directory of Open Access Journals (Sweden)

    Andrew eZaldivar

    2014-05-01

    Full Text Available The Allen Brain Atlas-Driven Visualizations (ABADV is a publicly accessible web-based tool created to retrieve and visualize expression energy data from the Allen Brain Atlas (ABA across multiple genes and brain structures. Though the ABA offers their own search engine and software for researchers to view their growing collection of online public data sets, including extensive gene expression and neuroanatomical data from human and mouse brain, many of their tools limit the amount of genes and brain structures researchers can view at once. To complement their work, ABADV generates multiple pie charts, bar charts and heat maps of expression energy values for any given set of genes and brain structures. Such a suite of free and easy-to-understand visualizations allows for easy comparison of gene expression across multiple brain areas. In addition, each visualization links back to the ABA so researchers may view a summary of the experimental detail. ABADV is currently supported on modern web browsers and is compatible with expression energy data from the Allen Mouse Brain Atlas in situ hybridization data. By creating this web application, researchers can immediately obtain and survey numerous amounts of expression energy data from the ABA, which they can then use to supplement their work or perform meta-analysis. In the future, we hope to enable ABADV across multiple data resources.

  11. Advances in upper extremity prosthetics.

    Science.gov (United States)

    Zlotolow, Dan A; Kozin, Scott H

    2012-11-01

    Until recently, upper extremity prostheses had changed little since World War II. In 2006, the Defense Advanced Research Projects Agency responded to an increasing number of military amputees with the Revolutionizing Prosthetics program. The program has yielded several breakthroughs both in the engineering of new prosthetic arms and in the control of those arms. Direct brain-wave control of a limb with 22° of freedom may be within reach. In the meantime, advances such as individually powered digits have opened the door to multifunctional full and partial hand prostheses. Restoring sensation to the prosthetic limb remains a major challenge to full integration of the limb into a patient's self-image.

  12. Rehabilitation and Prosthetic Services

    Science.gov (United States)

    ... Service » Prosthetic & Sensory Aids Service (PSAS) Rehabilitation and Prosthetic Services Menu Menu Rehabilitation and Prosthetics Rehabilitation and ... Enter ZIP code here Enter ZIP code here Prosthetic & Sensory Aids Service (PSAS) Our Mission The mission ...

  13. Prosthetic advances.

    Science.gov (United States)

    Harvey, Zach T; Potter, Benjamin K; Vandersea, James; Wolf, Erik

    2012-01-01

    Much of the current prosthetic technology is based on developments that have taken place during or directly following times of war. These developments have evolved and improved over the years, and now there are many more available options to provide a comfortable, cosmetic, and highly functional prosthesis. Even so, problems with fit and function persist. Recent developments have addressed some of the limitations faced by some military amputees. On-board microprocessor-controlled joints are making prosthetic arms and legs more responsive to environmental barriers and easier to control by the user. Advances in surgical techniques will allow more intuitive control and secure attachment to the prosthesis. As surgical techniques progress and permeate into standard practice, more sophisticated powered prosthetic devices will become commonplace, helping to restore neuromuscular loss of function. Prognoses following amputation will certainly rise, factoring into the surgeon's decision to attempt to save a limb versus perform an amputation.

  14. Brain systems for visual perspective taking and action perception.

    Science.gov (United States)

    Mazzarella, Elisabetta; Ramsey, Richard; Conson, Massimiliano; Hamilton, Antonia

    2013-01-01

    Taking another person's viewpoint and making sense of their actions are key processes that guide social behavior. Previous neuroimaging investigations have largely studied these processes separately. The current study used functional magnetic resonance imaging to examine how the brain incorporates another person's viewpoint and actions into visual perspective judgments. Participants made a left-right judgment about the location of a target object from their own (egocentric) or an actor's visual perspective (altercentric). Actor location varied around a table and the actor was either reaching or not reaching for the target object. Analyses examined brain regions engaged in the egocentric and altercentric tasks, brain regions where response magnitude tracked the orientation of the actor in the scene and brain regions sensitive to the action performed by the actor. The blood oxygen level-dependent (BOLD) response in dorsomedial prefrontal cortex (dmPFC) was sensitive to actor orientation in the altercentric task, whereas the response in right inferior frontal gyrus (IFG) was sensitive to actor orientation in the egocentric task. Thus, dmPFC and right IFG may play distinct but complementary roles in visual perspective taking (VPT). Observation of a reaching actor compared to a non-reaching actor yielded activation in lateral occipitotemporal cortex, regardless of task, showing that these regions are sensitive to body posture independent of social context. By considering how an observed actor's location and action influence the neural bases of visual perspective judgments, the current study supports the view that multiple neurocognitive "routes" operate during VPT.

  15. Unveiling the mystery of visual information processing in human brain.

    Science.gov (United States)

    Diamant, Emanuel

    2008-08-15

    It is generally accepted that human vision is an extremely powerful information processing system that facilitates our interaction with the surrounding world. However, despite extended and extensive research efforts, which encompass many exploration fields, the underlying fundamentals and operational principles of visual information processing in human brain remain unknown. We still are unable to figure out where and how along the path from eyes to the cortex the sensory input perceived by the retina is converted into a meaningful object representation, which can be consciously manipulated by the brain. Studying the vast literature considering the various aspects of brain information processing, I was surprised to learn that the respected scholarly discussion is totally indifferent to the basic keynote question: "What is information?" in general or "What is visual information?" in particular. In the old days, it was assumed that any scientific research approach has first to define its basic departure points. Why was it overlooked in brain information processing research remains a conundrum. In this paper, I am trying to find a remedy for this bizarre situation. I propose an uncommon definition of "information", which can be derived from Kolmogorov's Complexity Theory and Chaitin's notion of Algorithmic Information. Embracing this new definition leads to an inevitable revision of traditional dogmas that shape the state of the art of brain information processing research. I hope this revision would better serve the challenging goal of human visual information processing modeling.

  16. Unveiling the mystery of visual information processing in human brain

    CERN Document Server

    Diamant, Emanuel

    2008-01-01

    It is generally accepted that human vision is an extremely powerful information processing system that facilitates our interaction with the surrounding world. However, despite extended and extensive research efforts, which encompass many exploration fields, the underlying fundamentals and operational principles of visual information processing in human brain remain unknown. We still are unable to figure out where and how along the path from eyes to the cortex the sensory input perceived by the retina is converted into a meaningful object representation, which can be consciously manipulated by the brain. Studying the vast literature considering the various aspects of brain information processing, I was surprised to learn that the respected scholarly discussion is totally indifferent to the basic keynote question: "What is information?" in general or "What is visual information?" in particular. In the old days, it was assumed that any scientific research approach has first to define its basic departure points. ...

  17. The Connectome Visualization Utility: software for visualization of human brain networks.

    Science.gov (United States)

    LaPlante, Roan A; Douw, Linda; Tang, Wei; Stufflebeam, Steven M

    2014-01-01

    In analysis of the human connectome, the connectivity of the human brain is collected from multiple imaging modalities and analyzed using graph theoretical techniques. The dimensionality of human connectivity data is high, and making sense of the complex networks in connectomics requires sophisticated visualization and analysis software. The current availability of software packages to analyze the human connectome is limited. The Connectome Visualization Utility (CVU) is a new software package designed for the visualization and network analysis of human brain networks. CVU complements existing software packages by offering expanded interactive analysis and advanced visualization features, including the automated visualization of networks in three different complementary styles and features the special visualization of scalar graph theoretical properties and modular structure. By decoupling the process of network creation from network visualization and analysis, we ensure that CVU can visualize networks from any imaging modality. CVU offers a graphical user interface, interactive scripting, and represents data uses transparent neuroimaging and matrix-based file types rather than opaque application-specific file formats.

  18. Visual imagery influences brain responses to visual stimulation in bilateral cortical blindness.

    Science.gov (United States)

    de Gelder, Beatrice; Tamietto, Marco; Pegna, Alan J; Van den Stock, Jan

    2015-11-01

    Mental imagery is a powerful mechanism that may facilitate visual perception as well as compensate for it. The role of V1 in mental imagery is still a matter of debate. Our goal here was to investigate whether visual imagery was still possible in case of bilateral V1 destruction behaviorally evidenced by total clinical blindness and if so, whether it might boost residual visual perception. In a factorial fMRI design, faces, scenes or scrambled images were presented while a rare patient with cortical blindness over the whole visual field due to bilateral V1-lesions (TN) was instructed to imagine either an angry person or a neutral object (tree). The results show that visual imagery of a person activates frontal, parietal and occipital brain regions similar to control subjects and hence suggest that V1 is not necessary for visual imagery. In addition, the combination of visual stimulation and visual imagery of socio-emotional stimuli triggers activation in superior parietal lobule (SPL) and ventromedial (vmPFC) and dorsolateral prefrontal cortex (DLPFC). Finally, activation during residual vision, visual imagery and their interaction overlapped in the SPL, arguing for a central role of feeling in V1-independent vision and imagery.

  19. Do Visual Illusions Probe the Visual Brain?: Illusions in Action without a Dorsal Visual Stream

    Science.gov (United States)

    Coello, Yann; Danckert, James; Blangero, Annabelle; Rossetti, Yves

    2007-01-01

    Visual illusions have been shown to affect perceptual judgements more so than motor behaviour, which was interpreted as evidence for a functional division of labour within the visual system. The dominant perception-action theory argues that perception involves a holistic processing of visual objects or scenes, performed within the ventral,…

  20. Visualizing the site of drug action in living human brain

    Energy Technology Data Exchange (ETDEWEB)

    Suhara, Tetsuya [National Inst. of Radiological Sciences, Chiba (Japan)

    1997-03-01

    PET is the only technique available to date to measure molecular interactions in vivo, but the basic mechanism of molecular interaction in vivo is not yet fully understood. However, PET can allow visualization of various phenomena which we can not observe with in vitro techniques. Progress in PET study will provide a new viewpoint for drug development and the study of molecular mechanism in the brain. (J.P.N.)

  1. Hierarchical organization of brain functional network during visual task

    CERN Document Server

    Zhuo, Zhao; Fu, Zhong-Qian; Zhang, Jie

    2011-01-01

    In this paper, the brain functional networks derived from high-resolution synchronous EEG time series during visual task are generated by calculating the phase synchronization among the time series. The hierarchical modular organizations of these networks are systematically investigated by the fast Girvan-Newman algorithm. At the same time, the spatially adjacent electrodes (corresponding to EEG channels) are clustered into functional groups based on anatomical parcellation of brain cortex, and this clustering information are compared to that of the functional network. The results show that the modular architectures of brain functional network are in coincidence with that from the anatomical structures over different levels of hierarchy, which suggests that population of neurons performing the same function excite and inhibit in identical rhythms. The structure-function relationship further reveals that the correlations among EEG time series in the same functional group are much stronger than those in differe...

  2. Visual scanning and matching dysfunction in brain-damaged patients with drawing impairment.

    Science.gov (United States)

    Belleza, T; Rappaport, M; Hopkins, H K; Hall, K

    1979-03-01

    Visual matching and visual exploration were examined in 7 normal subjects and 20 brain-damaged patients with drawing impairment measured by the Bender Gestalt Visual-Motor Test. Right brain-damaged patients made significantly more errors of rotation and integration than left brain-damaged patients. Selecteded Bender figures were also used as stimuli for both visual matching and visual exploration tests. The ability to match Bender figures was found to be impaired in right but not left brain-damaged patients. All patients showed eye movement and fixation patterns different from those normals. Patients essentially had more fixations and shorter fixation durations. Significant intercorrelations were found between the total Bender Gestalt score and visual matching and visual exploration scores. These findings indicate that visual matching and visual exploration measures can be used to evaluate perceptual impairment in individuals who do not have adequate motor responses or where impaired motor responses may confound interpretations about visual cognitive impairment.

  3. Visual perception in the brain of a jumping spider.

    Science.gov (United States)

    Menda, Gil; Shamble, Paul S; Nitzany, Eyal I; Golden, James R; Hoy, Ronald R

    2014-11-03

    Jumping spiders (Salticidae) are renowned for a behavioral repertoire that can seem more vertebrate, or even mammalian, than spider-like in character. This is made possible by a unique visual system that supports their stalking hunting style and elaborate mating rituals in which the bizarrely marked and colored appendages of males highlight their song-and-dance displays. Salticids perform these tasks with information from four pairs of functionally specialized eyes, providing a near 360° field of view and forward-looking spatial resolution surpassing that of all insects and even some mammals, processed by a brain roughly the size of a poppy seed. Salticid behavior, evolution, and ecology are well documented, but attempts to study the neurophysiological basis of their behavior had been thwarted by the pressurized nature of their internal body fluids, making typical physiological techniques infeasible and restricting all previous neural work in salticids to a few recordings from the eyes. We report the first survey of neurophysiological recordings from the brain of a jumping spider, Phidippus audax (Salticidae). The data include single-unit recordings in response to artificial and naturalistic visual stimuli. The salticid visual system is unique in that high-acuity and motion vision are processed by different pairs of eyes. We found nonlinear interactions between the principal and secondary eyes, which can be inferred from the emergence of spatiotemporal receptive fields. Ecologically relevant images, including prey-like objects such as flies, elicited bursts of excitation from single units.

  4. Do visual illusions probe the visual brain? Illusions in action without a dorsal visual stream.

    Science.gov (United States)

    Coello, Yann; Danckert, James; Blangero, Annabelle; Rossetti, Yves

    2007-04-09

    Visual illusions have been shown to affect perceptual judgements more so than motor behaviour, which was interpreted as evidence for a functional division of labour within the visual system. The dominant perception-action theory argues that perception involves a holistic processing of visual objects or scenes, performed within the ventral, inferior temporal cortex. Conversely, visuomotor action involves the processing of the 3D relationship between the goal of the action and the body, performed predominantly within the dorsal, posterior parietal cortex. We explored the effect of well-known visual illusions (a size-contrast illusion and the induced Roelofs effect) in a patient (IG) suffering bilateral lesions of the dorsal visual stream. According to the perception-action theory, IG's perceptual judgements and control of actions should rely on the intact ventral stream and hence should both be sensitive to visual illusions. The finding that IG performed similarly to controls in three different illusory contexts argues against such expectations and shows, furthermore, that the dorsal stream does not control all aspects of visuomotor behaviour. Assuming that the patient's dorsal stream visuomotor system is fully lesioned, these results suggest that her visually guided action can be planned and executed independently of the dorsal pathways, possibly through the inferior parietal lobule.

  5. Brain functional network connectivity based on a visual task:visual information processing-related brain regions are signiifcantly activated in the task state

    Institute of Scientific and Technical Information of China (English)

    Yan-li Yang; Hong-xia Deng; Gui-yang Xing; Xiao-luan Xia; Hai-fang Li

    2015-01-01

    It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we inves-tigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state.Z-values in the vision-related brain regions were calculated, conifrming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental ifndings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception.

  6. Brain functional network connectivity based on a visual task: visual information processing-related brain regions are significantly activated in the task state

    Directory of Open Access Journals (Sweden)

    Yan-li Yang

    2015-01-01

    Full Text Available It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we investigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state. Z-values in the vision-related brain regions were calculated, confirming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental findings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception.

  7. Changes in brain morphology in albinism reflect reduced visual acuity.

    Science.gov (United States)

    Bridge, Holly; von dem Hagen, Elisabeth A H; Davies, George; Chambers, Claire; Gouws, Andre; Hoffmann, Michael; Morland, Antony B

    2014-07-01

    Albinism, in humans and many animal species, has a major impact on the visual system, leading to reduced acuity, lack of binocular function and nystagmus. In addition to the lack of a foveal pit, there is a disruption to the routing of the nerve fibers crossing at the optic chiasm, resulting in excessive crossing of fibers to the contralateral hemisphere. However, very little is known about the effect of this misrouting on the structure of the post-chiasmatic visual pathway, and the occipital lobes in particular. Whole-brain analyses of cortical thickness in a large cohort of subjects with albinism showed an increase in cortical thickness, relative to control subjects, particularly in posterior V1, corresponding to the foveal representation. Furthermore, mean cortical thickness across entire V1 was significantly greater in these subjects compared to controls and negatively correlated with visual acuity in albinism. Additionally, the group with albinism showed decreased gyrification in the left ventral occipital lobe. While the increase in cortical thickness in V1, also found in congenitally blind subjects, has been interpreted to reflect a lack of pruning, the decreased gyrification in the ventral extrastriate cortex may reflect the reduced input to the foveal regions of the ventral visual stream.

  8. Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

    2015-05-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing.

  9. Demonstration of a semi-autonomous hybrid brain-machine interface using human intracranial EEG, eye tracking, and computer vision to control a robotic upper limb prosthetic.

    Science.gov (United States)

    McMullen, David P; Hotson, Guy; Katyal, Kapil D; Wester, Brock A; Fifer, Matthew S; McGee, Timothy G; Harris, Andrew; Johannes, Matthew S; Vogelstein, R Jacob; Ravitz, Alan D; Anderson, William S; Thakor, Nitish V; Crone, Nathan E

    2014-07-01

    To increase the ability of brain-machine interfaces (BMIs) to control advanced prostheses such as the modular prosthetic limb (MPL), we are developing a novel system: the Hybrid Augmented Reality Multimodal Operation Neural Integration Environment (HARMONIE). This system utilizes hybrid input, supervisory control, and intelligent robotics to allow users to identify an object (via eye tracking and computer vision) and initiate (via brain-control) a semi-autonomous reach-grasp-and-drop of the object by the MPL. Sequential iterations of HARMONIE were tested in two pilot subjects implanted with electrocorticographic (ECoG) and depth electrodes within motor areas. The subjects performed the complex task in 71.4% (20/28) and 67.7% (21/31) of trials after minimal training. Balanced accuracy for detecting movements was 91.1% and 92.9%, significantly greater than chance accuracies (p system improvements implemented for the second subject. Our hybrid-BMI design prevented all but one baseline false positive from initiating the system. The novel approach demonstrated in this proof-of-principle study, using hybrid input, supervisory control, and intelligent robotics, addresses limitations of current BMIs.

  10. Encouraging expressions affect the brain and alter visual attention.

    Directory of Open Access Journals (Sweden)

    Manuel Martín-Loeches

    Full Text Available BACKGROUND: Very often, encouraging or discouraging expressions are used in competitive contexts, such as sports practice, aiming at provoking an emotional reaction on the listener and, consequently, an effect on subsequent cognition and/or performance. However, the actual efficiency of these expressions has not been tested scientifically. METHODOLOGY/PRINCIPAL FINDINGS: To fill this gap, we studied the effects of encouraging, discouraging, and neutral expressions on event-related brain electrical activity during a visual selective attention task in which targets were determined by location, shape, and color. Although the expressions preceded the attentional task, both encouraging and discouraging messages elicited a similar long-lasting brain emotional response present during the visuospatial task. In addition, encouraging expressions were able to alter the customary working pattern of the visual attention system for shape selection in the attended location, increasing the P1 and the SP modulations while simultaneously fading away the SN. CONCLUSIONS/SIGNIFICANCE: This was interpreted as an enhancement of the attentional processes for shape in the attended location after an encouraging expression. It can be stated, therefore, that encouraging expressions, as those used in sport practice, as well as in many other contexts and situations, do seem to be efficient in exerting emotional reactions and measurable effects on cognition.

  11. Electrophysiological recording of the brain, visualization, prediction, and interconnectivity

    Science.gov (United States)

    Talakoub, Omid

    The human brain is a complex network of interconnected neurons. The aim of neuroscience and neuroengineering is to decode the neural activity, visualize it and try to better understand how neurons communicate with each other. This dissertation comprises four contributions to the area. These four topics are discussing how functional relationship between brain activity and movement can be found and whether common features found in different regions are correlated (phase-locked). First, the method of chirplet decomposition offers a new way to visualize the time-frequency content of non-stationary signals with higher resolution than previously possible. The use of Wigner-Ville distribution together with chirplet decomposition allows a clearer visualization in terms of both the temporal and frequency details with detail higher than previously achieved using other methods including Choi-Williams and spectrogram. Second, an improved method of averaging of neural signals over repeated trials is introduced whereby slight variations in the alignment of the neural signal over time is corrected through the use of nonlinear shifts. In earlier studies, time alignment has been performed using linear shift (e.g. alignment with movement onset), but this process alone is not sufficient when the signal timing changes differently over time. To overcome this issue, nonlinear transformations were found to remove any temporal variabilities in the way the task was performed. Third, a multilinear model is demonstrated showing how limb velocity in a reach task can be predicted from neuroelectrical activity. The model, after fitting, suggested that high frequency oscillations have sufficient information for both detection of movement onset and reconstruction of its movement. The use of a linear model reduces the overall computational requirements and simplifies the reconstruction of movement kinematics. Finally, a fourth method involving the measurement of coherence over time reveals how

  12. Emotion processing in the visual brain: a MEG analysis.

    Science.gov (United States)

    Peyk, Peter; Schupp, Harald T; Elbert, Thomas; Junghöfer, Markus

    2008-06-01

    Recent functional magnetic resonance imaging (fMRI) and event-related brain potential (ERP) studies provide empirical support for the notion that emotional cues guide selective attention. Extending this line of research, whole head magneto-encephalogram (MEG) was measured while participants viewed in separate experimental blocks a continuous stream of either pleasant and neutral or unpleasant and neutral pictures, presented for 330 ms each. Event-related magnetic fields (ERF) were analyzed after intersubject sensor coregistration, complemented by minimum norm estimates (MNE) to explore neural generator sources. Both streams of analysis converge by demonstrating the selective emotion processing in an early (120-170 ms) and a late time interval (220-310 ms). ERF analysis revealed that the polarity of the emotion difference fields was reversed across early and late intervals suggesting distinct patterns of activation in the visual processing stream. Source analysis revealed the amplified processing of emotional pictures in visual processing areas with more pronounced occipito-parieto-temporal activation in the early time interval, and a stronger engagement of more anterior, temporal, regions in the later interval. Confirming previous ERP studies showing facilitated emotion processing, the present data suggest that MEG provides a complementary look at the spread of activation in the visual processing stream.

  13. Visualization and modelling of STLmax topographic brain activity maps.

    Science.gov (United States)

    Mammone, Nadia; Principe, José C; Morabito, Francesco C; Shiau, Deng S; Sackellares, J Chris

    2010-06-15

    This paper evaluates the descriptive power of brain topography based on a dynamical parameter, the Short-Term Maximum Lyapunov Exponent (STLmax), estimated from EEG, for finding out a relationship of STLmax spatial distribution with the onset zone and with the mechanisms leading to epileptic seizures. Our preliminary work showed that visual assessment of STLmax topography exhibited a link with the location of seizure onset zone. The objective of the present work is to model the spatial distribution of STLmax in order to automatically extract these features from the maps. One-hour preictal segments from four long-term continuous EEG recordings (two scalp and two intracranial) were processed and the corresponding STLmax profiles were estimated. The spatial STLmax maps were modelled by a combination of two Gaussians functions. The parameters of the fitted model allow automatic extraction of quantitative information about the spatial distribution of STLmax: the EEG signal recorded from the brain region where seizures originate exhibited low-STLmax levels, long before the seizure onset, in 3 out of 4 patients (1 out of 2 of scalp patients and 2 out of 2 in intracranial patients). Topographic maps extracted directly from the EEG power did not provide useful information about the location, therefore we conclude that the analysis so far carried out suggests the possibility of using a model of STLmax topography as a tool for monitoring the evolution of epileptic brain dynamics. In the future, a more elaborate approach will be investigated in order to improve the specificity of the method.

  14. Brain activity patterns uniquely supporting visual feature integration after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Anjali eRaja Beharelle

    2011-12-01

    Full Text Available Traumatic brain injury (TBI patients typically respond more slowly and with more variability than controls during tasks of attention requiring speeded reaction time. These behavioral changes are attributable, at least in part, to diffuse axonal injury (DAI, which affects integrated processing in distributed systems. Here we use a multivariate method sensitive to distributed neural activity to compare brain activity patterns of patients with chronic phase moderate-to-severe TBI to those of controls during performance on a visual feature-integration task assessing complex attentional processes that has previously shown sensitivity to TBI. The TBI patients were carefully screened to be free of large focal lesions that can affect performance and brain activation independently of DAI. The task required subjects to hold either one or three features of a target in mind while suppressing responses to distracting information. In controls, the multi-feature condition activated a distributed network including limbic, prefrontal, and medial temporal structures. TBI patients engaged this same network in the single-feature and baseline conditions. In multi-feature presentations, TBI patients alone activated additional frontal, parietal, and occipital regions. These results are consistent with neuroimaging studies using tasks assessing different cognitive domains, where increased spread of brain activity changes was associated with TBI. Our results also extend previous findings that brain activity for relatively moderate task demands in TBI patients is similar to that associated with of high task demands in controls.

  15. BrainFrame: a knowledge visualization system for the neurosciences

    Science.gov (United States)

    Barnes, Steven J.; Shaw, Chris D.

    2009-01-01

    Neuroscience has benefited from an explosion of new experimental techniques; many have only become feasible in the wake of improvements in computing speed and data storage. At the same time, these new computation-intensive techniques have led to a growing gulf between the data and the knowledge extracted from those data. That is, in the neurosciences there is a paucity of effective knowledge management techniques and an accelerating accumulation of experimental data. The purpose of the project described in the present paper is to create a visualization of the knowledge base of the neurosciences. At run-time, this 'BrainFrame' project accesses several web-based ontologies and generates a semantically zoomable representation of any one of many levels of the human nervous system.

  16. Gaitography applied to prosthetic walking.

    Science.gov (United States)

    Roerdink, Melvyn; Cutti, Andrea G; Summa, Aurora; Monari, Davide; Veronesi, Davide; van Ooijen, Mariëlle W; Beek, Peter J

    2014-11-01

    During walking on an instrumented treadmill with an embedded force platform or grid of pressure sensors, center-of-pressure (COP) trajectories exhibit a characteristic butterfly-like shape, reflecting the medio-lateral and anterior-posterior weight shifts associated with alternating steps. We define "gaitography" as the analysis of such COP trajectories during walking (the "gaitograms"). It is currently unknown, however, if gaitography can be employed to characterize pathological gait, such as lateralized gait impairments. We therefore registered gaitograms for a heterogeneous sample of persons with a trans-femoral and trans-tibial amputation during treadmill walking at a self-selected comfortable speed. We found that gaitograms directly visualize between-person differences in prosthetic gait in terms of step width and the relative duration of prosthetic and non-prosthetic single-support stance phases. We further demonstrated that one should not only focus on the gaitogram's shape but also on the time evolution along that shape, given that the COP evolves much slower in the single-support phase than in the double-support phase. Finally, commonly used temporal and spatial prosthetic gait characteristics were derived, revealing both individual and systematic differences in prosthetic and non-prosthetic step lengths, step times, swing times, and double-support durations. Because gaitograms can be rapidly collected in an unobtrusive and markerless manner over multiple gait cycles without constraining foot placement, clinical application of gaitography seems both expedient and appealing. Studies examining the repeatability of gaitograms and evaluating gaitography-based gait characteristics against a gold standard with known validity and reliability are required before gaitography can be clinically applied.

  17. Visualization and volumetric structures from MR images of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, B.; Johnston, W.; Robertson, D.

    1994-03-01

    Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.

  18. Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains

    Energy Technology Data Exchange (ETDEWEB)

    Habib, A.C.; Zheng, W.; Haacke, E.M.; Webb, S.; Nichol, H.; /SLAC

    2012-07-17

    To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.

  19. Microprocessor prosthetic knees.

    Science.gov (United States)

    Berry, Dale

    2006-02-01

    This article traces the development of microprocessor prosthetic knees from early research in the 1970s to the present. Read about how microprocessor knees work, functional options, patient selection, and the future of this prosthetic.

  20. Prosthetic Knee Systems

    Science.gov (United States)

    ... us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Prosthetic Knee Systems Translated into plain language by Helen ... Health Literacy Consulting Original article by Bill Dupes Prosthetic knee systems are among the most complex of ...

  1. Pursuing prosthetic electronic skin

    Science.gov (United States)

    Chortos, Alex; Liu, Jia; Bao, Zhenan

    2016-09-01

    Skin plays an important role in mediating our interactions with the world. Recreating the properties of skin using electronic devices could have profound implications for prosthetics and medicine. The pursuit of artificial skin has inspired innovations in materials to imitate skin's unique characteristics, including mechanical durability and stretchability, biodegradability, and the ability to measure a diversity of complex sensations over large areas. New materials and fabrication strategies are being developed to make mechanically compliant and multifunctional skin-like electronics, and improve brain/machine interfaces that enable transmission of the skin's signals into the body. This Review will cover materials and devices designed for mimicking the skin's ability to sense and generate biomimetic signals.

  2. Visual processing during recovery from vegetative state to consciousness: Comparing behavioral indices to brain responses

    NARCIS (Netherlands)

    Wijnen, V.J.; Eilander, H.J.; Gelder, B. de; Boxtel, G.J. Van

    2014-01-01

    BACKGROUND: Auditory stimulation is often used to evoke responses in unresponsive patients who have suffered severe brain injury. In order to investigate visual responses, we examined visual evoked potentials (VEPs) and behavioral responses to visual stimuli in vegetative patients during recovery to

  3. Networked neuroscience : brain scans and visual knowing at the intersection of atlases and databases

    NARCIS (Netherlands)

    Beaulieu, Anne; de Rijcke, Sarah; Coopmans, Catelijne; Woolgar, Steve

    2014-01-01

    This chapter discusses the development of authoritative collections of brain scans known as “brain atlases”, focusing in particular on how such scans are constituted as authoritative visual objects. Three dimensions are identified: first, brain scans are parts of suites of networked technologies rat

  4. Ultrasound imaging in lower limb prosthetics.

    Science.gov (United States)

    Douglas, Tania; Solomonidis, Stephan; Sandham, William; Spence, William

    2002-03-01

    The biomechanical interaction between the residual limb and the prosthetic socket determines the quality of fit of the socket in lower limb prosthetics. An understanding of this interaction and the development of quantitative measures to predict the quality of fit of the socket are important for optimal socket design. Finite-element modeling is used widely for biomechanical modeling of the limb/socket interaction and requires information on the internal and external geometry of the residual limb. Volumetric imaging methods such as X-ray computed tomography, magnetic resonance imaging, and ultrasound have been used to obtain residual limb shape information. Of these modalities, ultrasound has been introduced most recently and its development for visualization in prosthetics is the least mature. This paper reviews ultrasound image acquisition and processing methods as they have been applied in lower limb prosthetics.

  5. Visual emotional context modulates brain potentials elicited by unattended tones.

    Science.gov (United States)

    Sugimoto, Sayaka; Nittono, Hiroshi; Hori, Tadao

    2007-10-01

    To examine whether brain electrical responses to environmental stimuli were influenced by emotional contexts, event-related potentials (ERPs) elicited by nonstartle probe tones were recorded from 13 student volunteers while they were viewing emotionally positive, neutral, and negative slides of the International Affective Picture System. The auditory stimuli consisted of high-deviant (2000 Hz, p=.08), low-deviant (1050 Hz, p=.08), and standard (1000 Hz, p=.84) tones with a mean onset-to-onset interval of 600 ms. Participants were told to ignore the tones. High-deviant tones elicited a larger N1 (peaking around 100 ms) when participants were viewing negative slides than when viewing positive slides. The amplitude of the P2 elicited by standard tones (peaking around 170 ms) was smaller when participants were viewing positive slides than when viewing negative and neutral slides. The amplitude of the mismatch negativity (150-200 ms) tended to reduce during positive slide presentation, but this difference appeared to be due to reduction of the P2 elicited by standard tones. These findings suggest that visually induced emotional states have a sequential effect on auditory information processing, in that the influence of negative emotion appears at an earlier stage than that of positive emotion.

  6. Reading visually embodied meaning from the brain: Visually grounded computational models decode visual-object mental imagery induced by written text.

    Science.gov (United States)

    Anderson, Andrew James; Bruni, Elia; Lopopolo, Alessandro; Poesio, Massimo; Baroni, Marco

    2015-10-15

    Embodiment theory predicts that mental imagery of object words recruits neural circuits involved in object perception. The degree of visual imagery present in routine thought and how it is encoded in the brain is largely unknown. We test whether fMRI activity patterns elicited by participants reading objects' names include embodied visual-object representations, and whether we can decode the representations using novel computational image-based semantic models. We first apply the image models in conjunction with text-based semantic models to test predictions of visual-specificity of semantic representations in different brain regions. Representational similarity analysis confirms that fMRI structure within ventral-temporal and lateral-occipital regions correlates most strongly with the image models and conversely text models correlate better with posterior-parietal/lateral-temporal/inferior-frontal regions. We use an unsupervised decoding algorithm that exploits commonalities in representational similarity structure found within both image model and brain data sets to classify embodied visual representations with high accuracy (8/10) and then extend it to exploit model combinations to robustly decode different brain regions in parallel. By capturing latent visual-semantic structure our models provide a route into analyzing neural representations derived from past perceptual experience rather than stimulus-driven brain activity. Our results also verify the benefit of combining multimodal data to model human-like semantic representations.

  7. Acute Exposure to Perchlorethylene alters Rat Visual Evoked Potentials in Relation to Brain Concentration

    Science.gov (United States)

    These experiments sought to establish a dose-effect relationship between the concentration of perchloroethylene (PCE) in brain tissue and concurrent changes in visual function. A physiologically-based pharmacokinetic (PBPK) model was implemented to predict concentrations of PCE ...

  8. Prevention of Prosthetic Dentistry

    Directory of Open Access Journals (Sweden)

    Eremin O.V.

    2011-03-01

    Full Text Available Prevention in prosthetic dentistry is not just a regular oral hygiene and the prevention of caries in the early stages of its development. The initial goal of orthopedic and dental should be the ability to convey to the patient's sense of pros-thetics that proteziruya one saved more. An example is included prosthetic dental arch defects with bridges or single artificial crowns on implants that will prevent movement of teeth and the continuity of the dentition

  9. Three-dimensional X-ray visualization of axonal tracts in mouse brain hemisphere

    CERN Document Server

    Mizutani, Ryuta; Ohtsuka, Masato; Miura, Hiromi; Hoshino, Masato; Takeuchi, Akihisa; Uesugi, Kentaro

    2016-01-01

    Neurons transmit active potentials through axons, which are essential for the brain to function. In this study, the axonal networks of the murine brain were visualized with X-ray tomographic microscopy, also known as X-ray microtomography or micro-CT. Murine brain samples were freeze-dried to reconstitute the intrinsic contrast of tissue constituents and subjected to X-ray visualization. A whole brain hemisphere visualized by absorption contrast illustrated three-dimensional structures including those of the striatum, corpus callosum, and anterior commissure. Axonal tracts observed in the striatum start from the basal surface of the cerebral cortex and end at various positions in the basal ganglia. The distribution of X-ray attenuation coefficients indicated that differences in water and phospholipid content between the myelin sheath and surrounding tissue constituents account for the observed contrast. A rod-shaped cutout of brain tissue was also analyzed with a phase retrieval method, wherein tissue microst...

  10. Visual information about object size and object position are retained differently in the visual brain: Evidence from grasping studies.

    Science.gov (United States)

    Hesse, Constanze; Miller, Louisa; Buckingham, Gavin

    2016-10-01

    Many experiments have examined how the visual information used for action control is represented in our brain, and whether or not visually-guided and memory-guided hand movements rely on dissociable visual representations that are processed in different brain areas (dorsal vs. ventral). However, little is known about how these representations decay over longer time periods and whether or not different visual properties are retained in a similar fashion. In three experiments we investigated how information about object size and object position affect grasping as visual memory demands increase. We found that position information decayed rapidly with increasing delays between viewing the object and initiating subsequent actions - impacting both the accuracy of the transport component (lower end-point accuracy) and the grasp component (larger grip apertures) of the movement. In contrast, grip apertures and fingertip forces remained well-adjusted to target size in conditions in which positional information was either irrelevant or provided, regardless of delay, indicating that object size is encoded in a more stable manner than object position. The findings provide evidence that different grasp-relevant properties are encoded differently by the visual system. Furthermore, we argue that caution is required when making inferences about object size representations based on alterations in the grip component as these variations are confounded with the accuracy with which object position is represented. Instead fingertip forces seem to provide a reliable and confound-free measure to assess internal size estimations in conditions of increased visual uncertainty.

  11. Invariance of brain-wave representations of simple visual images and their names.

    Science.gov (United States)

    Suppes, P; Han, B; Epelboim, J; Lu, Z L

    1999-12-07

    In two experiments, electric brain waves of 14 subjects were recorded under several different conditions to study the invariance of brain-wave representations of simple patches of colors and simple visual shapes and their names, the words blue, circle, etc. As in our earlier work, the analysis consisted of averaging over trials to create prototypes and test samples, to both of which Fourier transforms were applied, followed by filtering and an inverse transformation to the time domain. A least-squares criterion of fit between prototypes and test samples was used for classification. The most significant results were these. By averaging over different subjects, as well as trials, we created prototypes from brain waves evoked by simple visual images and test samples from brain waves evoked by auditory or visual words naming the visual images. We correctly recognized from 60% to 75% of the test-sample brain waves. The general conclusion is that simple shapes such as circles and single-color displays generate brain waves surprisingly similar to those generated by their verbal names. These results, taken together with extensive psychological studies of auditory and visual memory, strongly support the solution proposed for visual shapes, by Bishop Berkeley and David Hume in the 18th century, to the long-standing problem of how the mind represents simple abstract ideas.

  12. Involvement of the right inferior longitudinal fascicle in visual hemiagnosia: a brain stimulation mapping study.

    Science.gov (United States)

    Fernández Coello, Alejandro; Duvaux, Sophie; De Benedictis, Alessandro; Matsuda, Ryosuke; Duffau, Hugues

    2013-01-01

    Neural foundations underlying visual agnosia are poorly understood. The authors present the case of a patient who underwent awake surgery for a right basal temporooccipital low-grade glioma in which direct electrostimulation was used both at the cortical and subcortical level. Brain mapping over the inferior longitudinal fascicle generated contralateral visual hemiagnosia. These original findings are in agreement with recent tractography data that have confirmed the existence of an occipitotemporal pathway connecting occipital visual input to higher-level processing in temporal lobe structures. This is the first report of a true transient visual hemiagnosia elicited through electrostimulation, supporting the crucial role of inferior longitudinal fascicle in visual recognition.

  13. The predicting brain: anticipation of moving objects in human visual cortex

    NARCIS (Netherlands)

    Schellekens, W.

    2015-01-01

    The human brain is nearly constantly subjected to visual motion signals originating from a large variety of external sources. It is the job of the central nervous system to determine correspondence among visual motion input across spatially distant locations within certain time frames. In order to c

  14. Rehabilitation of Visual and Perceptual Dysfunction after Severe Traumatic Brain Injury

    Science.gov (United States)

    2014-05-01

    patients for the clinician. Journal of Psychiatric Research. 1975;12:189-198. 27. Schenkenberg T, Bradforn DC, Ajax ET. Line bisection and unilateral visual...AD_________________ Award Number: W81XWH-11-2-0082 TITLE: Rehabilitation of Visual and Perceptual Dysfunction after Severe...From - To) 01 March 2011-28 February 2014 4. TITLE AND SUBTITLE Rehabilitation of Visual and Perceptual Dysfunction after Severe Traumatic Brain

  15. Visual and somatic sensory feedback of brain activity for intuitive surgical robot manipulation.

    Science.gov (United States)

    Miura, Satoshi; Matsumoto, Yuya; Kobayashi, Yo; Kawamura, Kazuya; Nakashima, Yasutaka; Fujie, Masakatsu G

    2015-01-01

    This paper presents a method to evaluate the hand-eye coordination of the master-slave surgical robot by measuring the activation of the intraparietal sulcus in users brain activity during controlling virtual manipulation. The objective is to examine the changes in activity of the intraparietal sulcus when the user's visual or somatic feedback is passed through or intercepted. The hypothesis is that the intraparietal sulcus activates significantly when both the visual and somatic sense pass feedback, but deactivates when either visual or somatic is intercepted. The brain activity of three subjects was measured by the functional near-infrared spectroscopic-topography brain imaging while they used a hand controller to move a virtual arm of a surgical simulator. The experiment was performed several times with three conditions: (i) the user controlled the virtual arm naturally under both visual and somatic feedback passed, (ii) the user moved with closed eyes under only somatic feedback passed, (iii) the user only gazed at the screen under only visual feedback passed. Brain activity showed significantly better control of the virtual arm naturally (pmoving with closed eyes or only gazing among all participants. In conclusion, the brain can activate according to visual and somatic sensory feedback agreement.

  16. The Colorful Brain: Visualization of EEG Background Patterns

    NARCIS (Netherlands)

    Putten, van Michel J.A.M

    2008-01-01

    This article presents a method to transform routine clinical EEG recordings to an alternative visual domain. The method is intended to support the classic visual interpretation of the EEG background pattern and to facilitate communication about relevant EEG characteristics. In addition, it provides

  17. Researchers Find Essential Brain Circuit in Visual Development

    Science.gov (United States)

    ... helps dictate how the eyes connect to the brain. The research, funded by the National Institutes of Health, has ... gov . NINDS is the nation’s leading funder of research on the brain and nervous system. The NINDS mission is to ...

  18. Visualizing Neuroscience: Learning about the Brain through Art

    Science.gov (United States)

    Chudler, Eric H.; Konrady, Paula

    2006-01-01

    Neuroscience is a subject that can motivate, excite, and stimulate the curiosity of everyone However, the study of the brain is made difficult by an abundance of new vocabulary words and abstract concepts. Although neuroscience has the potential to inspire students, many teachers find it difficult to include a study of the brain in their…

  19. In vitro study of biofilm growth on biologic prosthetics.

    Science.gov (United States)

    Bellows, Charles; Smith, Alison

    2014-01-01

    Biologic prosthetics are increasingly used for the repair of abdominal wall hernia defects but can become infected as a result of peri- or early post-operative bacterial contamination. Data evaluating biofilm formation on biologic prosthetics is lacking. The aim of this study was to investigate the influence of different biologic prosthetics on the growth behavior of two different bacterial species and their ability to form biofilms. Methicillin resistant Staphylococcus aureus (MRSA) or Pseudomrnonas aeruginosa were incubated on disks of two biologic prosthetics-human acellular dermis (ADM), and porcine small intestinal submucosa (SIS). The bacteria were allowed to attach to the prosthetics and propagate into mature biofilms for 24 hours at 370C. Images of biofilms were obtained using confocal microscopy and scanning electron microscopy (SEM). The number of viable cells and the biofilm biomass were quantified by colony forming units (CFUs) and crystal violet staining respectively. Analysis of variance was performed to compare the mean values for the different prosthetics. Each biologic matrix had a distinct surface characteristic. SEM visualized mature biofilms characterized by highly organized multi-cellular structures on surface of both biologic prosthetics. Quantification of bacterial growth over time showed that ADM had the lowest CFUs and biofilm biomass at 24 hours post-inoculation compared to SIS for both bacterial strains. MRSA and P. aeruginosa can form mature biofilms on biologic prosthetics but the relative abundance of the biofilm varies on different prosthetic constructs. Biologic material composition and manufacturing methods may influence bacterial adherence.

  20. Predictive visual tracking: specificity in mild traumatic brain injury and sleep deprivation.

    Science.gov (United States)

    Maruta, Jun; Heaton, Kristin J; Maule, Alexis L; Ghajar, Jamshid

    2014-06-01

    We tested whether reduced cognitive function associated with mild traumatic brain injury (mTBI) and sleep deprivation can be detected and distinguished using indices of predictive visual tracking. A circular visual tracking test was given to 13 patients with acute mTBI (recruited within 2 weeks of injury), 127 normal control subjects, and 43 healthy subjects who were fatigued by 26-hour sleep deprivation. Eye movement was monitored with video-oculography. In the mTBI-related portion of the study, visual tracking performance of acute mTBI patients was significantly worse than normal subjects (p visual tracking performance (p visual tracking than sleep-deprived subjects that could also be identified with different visual tracking indices, indicating possible different neurophysiological mechanisms. Results suggest that cognitive impairment associated with mTBI and fatigue may be triaged with the aid of visual tracking measures.

  1. Structural and functional correlates of visual field asymmetry in the human brain by diffusion kurtosis MRI and functional MRI.

    Science.gov (United States)

    O'Connell, Caitlin; Ho, Leon C; Murphy, Matthew C; Conner, Ian P; Wollstein, Gadi; Cham, Rakie; Chan, Kevin C

    2016-11-09

    Human visual performance has been observed to show superiority in localized regions of the visual field across many classes of stimuli. However, the underlying neural mechanisms remain unclear. This study aims to determine whether the visual information processing in the human brain is dependent on the location of stimuli in the visual field and the corresponding neuroarchitecture using blood-oxygenation-level-dependent functional MRI (fMRI) and diffusion kurtosis MRI, respectively, in 15 healthy individuals at 3 T. In fMRI, visual stimulation to the lower hemifield showed stronger brain responses and larger brain activation volumes than the upper hemifield, indicative of the differential sensitivity of the human brain across the visual field. In diffusion kurtosis MRI, the brain regions mapping to the lower visual field showed higher mean kurtosis, but not fractional anisotropy or mean diffusivity compared with the upper visual field. These results suggested the different distributions of microstructural organization across visual field brain representations. There was also a strong positive relationship between diffusion kurtosis and fMRI responses in the lower field brain representations. In summary, this study suggested the structural and functional brain involvements in the asymmetry of visual field responses in humans, and is important to the neurophysiological and psychological understanding of human visual information processing.

  2. Sustained Rhythmic Brain Activity Underlies Visual Motion Perception in Zebrafish

    Directory of Open Access Journals (Sweden)

    Verónica Pérez-Schuster

    2016-10-01

    Full Text Available Following moving visual stimuli (conditioning stimuli, CS, many organisms perceive, in the absence of physical stimuli, illusory motion in the opposite direction. This phenomenon is known as the motion aftereffect (MAE. Here, we use MAE as a tool to study the neuronal basis of visual motion perception in zebrafish larvae. Using zebrafish eye movements as an indicator of visual motion perception, we find that larvae perceive MAE. Blocking eye movements using optogenetics during CS presentation did not affect MAE, but tectal ablation significantly weakened it. Using two-photon calcium imaging of behaving GCaMP3 larvae, we find post-stimulation sustained rhythmic activity among direction-selective tectal neurons associated with the perception of MAE. In addition, tectal neurons tuned to the CS direction habituated, but neurons in the retina did not. Finally, a model based on competition between direction-selective neurons reproduced MAE, suggesting a neuronal circuit capable of generating perception of visual motion.

  3. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  4. Localization of MEG human brain responses to retinotopic visual stimuli with contrasting source reconstruction approaches

    Science.gov (United States)

    Cicmil, Nela; Bridge, Holly; Parker, Andrew J.; Woolrich, Mark W.; Krug, Kristine

    2014-01-01

    Magnetoencephalography (MEG) allows the physiological recording of human brain activity at high temporal resolution. However, spatial localization of the source of the MEG signal is an ill-posed problem as the signal alone cannot constrain a unique solution and additional prior assumptions must be enforced. An adequate source reconstruction method for investigating the human visual system should place the sources of early visual activity in known locations in the occipital cortex. We localized sources of retinotopic MEG signals from the human brain with contrasting reconstruction approaches (minimum norm, multiple sparse priors, and beamformer) and compared these to the visual retinotopic map obtained with fMRI in the same individuals. When reconstructing brain responses to visual stimuli that differed by angular position, we found reliable localization to the appropriate retinotopic visual field quadrant by a minimum norm approach and by beamforming. Retinotopic map eccentricity in accordance with the fMRI map could not consistently be localized using an annular stimulus with any reconstruction method, but confining eccentricity stimuli to one visual field quadrant resulted in significant improvement with the minimum norm. These results inform the application of source analysis approaches for future MEG studies of the visual system, and indicate some current limits on localization accuracy of MEG signals. PMID:24904268

  5. Localization of MEG human brain responses to retinotopic visual stimuli with contrasting source reconstruction approaches

    Directory of Open Access Journals (Sweden)

    Nela eCicmil

    2014-05-01

    Full Text Available Magnetoencephalography (MEG allows the physiological recording of human brain activity at high temporal resolution. However, spatial localization of the source of the MEG signal is an ill-posed problem as the signal alone cannot constrain a unique solution and additional prior assumptions must be enforced. An adequate source reconstruction method for investigating the human visual system should place the sources of early visual activity in known locations in the occipital cortex. We localized sources of retinotopic MEG signals from the human brain with contrasting reconstruction approaches (minimum norm, multiple sparse priors, and beamformer and compared these to the visual retinotopic map obtained with fMRI in the same individuals. When reconstructing brain responses to visual stimuli that differed by angular position, we found reliable localization to the appropriate retinotopic visual field quadrant by a minimum norm approach and by beamforming. Retinotopic map eccentricity in accordance with the fMRI map could not consistently be localized using an annular stimulus with any reconstruction method, but confining eccentricity stimuli to one visual field quadrant resulted in significant improvement with the minimum norm. These results inform the application of source analysis approaches for future MEG studies of the visual system, and indicate some current limits on localization accuracy of MEG signals.

  6. The colorful brain: visualization of EEG background patterns.

    Science.gov (United States)

    van Putten, Michel J A M

    2008-04-01

    This article presents a method to transform routine clinical EEG recordings to an alternative visual domain. The method is intended to support the classic visual interpretation of the EEG background pattern and to facilitate communication about relevant EEG characteristics. In addition, it provides various quantitative features. The EEG features used in the transformation include color-coded time-frequency representations of two novel symmetry measures and a synchronization measure, based on a nearest-neighbor coherence estimate. This triplet captures three highly relevant aspects of the dynamics of the EEG background pattern, which correlate strongly with various neurologic conditions. In particular, it quantifies and visualizes the spatiotemporal distribution of the EEG power in the anterioposterior and lateral direction, and the short-distance coherence. The potential clinical use is illustrated by application of the proposed technique to various normal and abnormal EEGs, including seizure activity and the transition to sleep. The proposed transformation visualizes various essential elements of EEG background patterns. Quantitative analysis of clinical EEG recordings and transformation to alternative domains assists in the interpretation and contributes to an objective interpretation.

  7. The nature of consciousness in the visually deprived brain

    DEFF Research Database (Denmark)

    Kupers, Ron; Pietrini, Pietro; Ricciardi, Emiliano

    2011-01-01

    Vision plays a central role in how we represent and interact with the world around us. The primacy of vision is structurally imbedded in cortical organization as about one-third of the cortical surface in primates is involved in visual processes. Consequently, the loss of vision, either at birth ...

  8. Miniature Brain Decision Making in Complex Visual Environments

    Science.gov (United States)

    2008-07-18

    release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The grantee investigated, using the honeybee (Apis mellifera ) as a model...successful for understanding face processing in both human adults and infants. Individual honeybees (Apis mellifera ) were trained with...for 30 bees (group 3) of the target stimuli. Bernard J, Stach S, Giurfa M (2007) Categorization of visual stimuli in the honeybee Apis mellifera

  9. DF's visual brain in action: the role of tactile cues.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Byrne, Caitlin M; Goodale, Melvyn A

    2014-03-01

    Patient DF, an extensively-tested woman with visual form agnosia from ventral-stream damage, is able to scale her grip aperture to match a goal object's geometry when reaching out to pick it up, despite being unable to explicitly distinguish amongst objects on the basis of their different geometries. Using evidence from a range of sources, including functional MRI, we have proposed that she does this through a functionally intact visuomotor system housed within the dorsal stream of the posterior parietal lobe. More recently, however, Schenk (2012a). The Journal of Neuroscience, 32(6), 2013-2017; Schenk (2012b). Trends in Cognitive Sciences, 16(5), 258-259. has argued that DF performs well in visually guided grasping, not through spared and functioning visuomotor networks in the dorsal stream, but because haptic feedback about the locations of the edges of the target is available to calibrate her grasps in such tasks, whereas it is not available in standard visual perceptual tasks. We have tested this 'calibration hypothesis' directly, by presenting DF with a grasping task in which the visible width of a target varied from trial to trial while its actual width remained the same. According to the calibration hypothesis, because haptic feedback was completely uninformative, DF should be unable to calibrate her grip aperture in this task. Contrary to this prediction, we found that DF continued to scale her grip aperture to the visual width of the targets and did so well within the range of healthy controls. We also found that DF's inability to distinguish shapes perceptually is not improved by providing haptic feedback. These findings strengthen the notion that DF's spared visuomotor abilities are driven largely by visual feedforward processing of the geometric properties of the target. Crucially, these findings also indicate that simple tactile contact with an object is needed for the visuomotor dorsal stream to be engaged, and accordingly enables DF to execute

  10. Brain activity underlying visual perception and attention as inferred from TMS-EEG: a review.

    Science.gov (United States)

    Taylor, Paul Christopher John; Thut, Gregor

    2012-04-01

    Probing brain functions by brain stimulation while simultaneously recording brain activity allows addressing major issues in cognitive neuroscience. We review recent studies where electroencephalography (EEG) has been combined with transcranial magnetic stimulation (TMS) in order to investigate possible neuronal substrates of visual perception and attention. TMS-EEG has been used to study both pre-stimulus brain activity patterns that affect upcoming perception, and also the stimulus-evoked and task-related inter-regional interactions within the extended visual-attentional network from which attention and perception emerge. Local processes in visual areas have been probed by directly stimulating occipital cortex while monitoring EEG activity and perception. Interactions within the attention network have been probed by concurrently stimulating frontal or parietal areas. The use of tasks manipulating implicit and explicit memory has revealed in addition a role for attentional processes in memory. Taken together, these studies helped to reveal that visual selection relies on spontaneous intrinsic activity in visual cortex prior to the incoming stimulus, their control by attention, and post-stimulus processes incorporating a re-entrant bias from frontal and parietal areas that depends on the task.

  11. Structural and functional brain changes beyond visual system in patients with advanced glaucoma.

    Science.gov (United States)

    Frezzotti, Paolo; Giorgio, Antonio; Motolese, Ilaria; De Leucio, Alessandro; Iester, Michele; Motolese, Eduardo; Federico, Antonio; De Stefano, Nicola

    2014-01-01

    In order to test the hypothesis that in primary open angle glaucoma (POAG), an important cause of irreversible blindness, a spreading of neurodegeneration occurs through the brain, we performed multimodal MRI and subsequent whole-brain explorative voxelwise analyses in 13 advanced POAG patients and 12 age-matched normal controls (NC). Altered integrity (decreased fractional anisotropy or increased diffusivities) of white matter (WM) tracts was found not only along the visual pathway of POAG but also in nonvisual WM tracts (superior longitudinal fascicle, anterior thalamic radiation, corticospinal tract, middle cerebellar peduncle). POAG patients also showed brain atrophy in both visual cortex and other distant grey matter (GM) regions (frontoparietal cortex, hippocampi and cerebellar cortex), decreased functional connectivity (FC) in visual, working memory and dorsal attention networks and increased FC in visual and executive networks. In POAG, abnormalities in structure and FC within and outside visual system correlated with visual field parameters in the poorer performing eyes, thus emphasizing their clinical relevance. Altogether, this represents evidence that a vision disorder such as POAG can be considered a widespread neurodegenerative condition.

  12. A simpler primate brain: the visual system of the marmoset monkey.

    Science.gov (United States)

    Solomon, Samuel G; Rosa, Marcello G P

    2014-01-01

    Humans are diurnal primates with high visual acuity at the center of gaze. Although primates share many similarities in the organization of their visual centers with other mammals, and even other species of vertebrates, their visual pathways also show unique features, particularly with respect to the organization of the cerebral cortex. Therefore, in order to understand some aspects of human visual function, we need to study non-human primate brains. Which species is the most appropriate model? Macaque monkeys, the most widely used non-human primates, are not an optimal choice in many practical respects. For example, much of the macaque cerebral cortex is buried within sulci, and is therefore inaccessible to many imaging techniques, and the postnatal development and lifespan of macaques are prohibitively long for many studies of brain maturation, plasticity, and aging. In these and several other respects the marmoset, a small New World monkey, represents a more appropriate choice. Here we review the visual pathways of the marmoset, highlighting recent work that brings these advantages into focus, and identify where additional work needs to be done to link marmoset brain organization to that of macaques and humans. We will argue that the marmoset monkey provides a good subject for studies of a complex visual system, which will likely allow an important bridge linking experiments in animal models to humans.

  13. Visual emotional context modulates brain potentials elicited by unattended tones

    OpenAIRE

    Sugimoto, Sayaka; Nittono, Hiroshi; Hori, Tadao

    2007-01-01

    To examine whether brain electrical responses to environmental stimuli were influenced by emotional contexts, event-related potentials (ERPs) elicited by nonstartle probe tones were recorded from 13 student volunteers while they were viewing emotionally positive, neutral, and negative slides of the International Affective Picture System. The auditory stimuli consisted of high-deviant (2000 Hz, p=.08), low-deviant (1050 Hz, p=.08), and standard (1000 Hz, p=.84) tones with a mean onset-to-onset...

  14. Stereoscopic Three-Dimensional Visualization Applied to Multimodal Brain Images: Clinical Applications and a Functional Connectivity Atlas.

    Directory of Open Access Journals (Sweden)

    Gonzalo M Rojas

    2014-11-01

    Full Text Available Effective visualization is central to the exploration and comprehension of brain imaging data. While MRI data are acquired in three-dimensional space, the methods for visualizing such data have rarely taken advantage of three-dimensional stereoscopic technologies. We present here results of stereoscopic visualization of clinical data, as well as an atlas of whole-brain functional connectivity. In comparison with traditional 3D rendering techniques, we demonstrate the utility of stereoscopic visualizations to provide an intuitive description of the exact location and the relative sizes of various brain landmarks, structures and lesions. In the case of resting state fMRI, stereoscopic 3D visualization facilitated comprehension of the anatomical position of complex large-scale functional connectivity patterns. Overall, stereoscopic visualization improves the intuitive visual comprehension of image contents, and brings increased dimensionality to visualization of traditional MRI data, as well as patterns of functional connectivity.

  15. Stereoscopic three-dimensional visualization applied to multimodal brain images: clinical applications and a functional connectivity atlas.

    Science.gov (United States)

    Rojas, Gonzalo M; Gálvez, Marcelo; Vega Potler, Natan; Craddock, R Cameron; Margulies, Daniel S; Castellanos, F Xavier; Milham, Michael P

    2014-01-01

    Effective visualization is central to the exploration and comprehension of brain imaging data. While MRI data are acquired in three-dimensional space, the methods for visualizing such data have rarely taken advantage of three-dimensional stereoscopic technologies. We present here results of stereoscopic visualization of clinical data, as well as an atlas of whole-brain functional connectivity. In comparison with traditional 3D rendering techniques, we demonstrate the utility of stereoscopic visualizations to provide an intuitive description of the exact location and the relative sizes of various brain landmarks, structures and lesions. In the case of resting state fMRI, stereoscopic 3D visualization facilitated comprehension of the anatomical position of complex large-scale functional connectivity patterns. Overall, stereoscopic visualization improves the intuitive visual comprehension of image contents, and brings increased dimensionality to visualization of traditional MRI data, as well as patterns of functional connectivity.

  16. The Development of Hand-Centered Visual Representations in the Primate Brain: A Computer Modeling Study Using Natural Visual Scenes.

    Science.gov (United States)

    Galeazzi, Juan M; Minini, Loredana; Stringer, Simon M

    2015-01-01

    Neurons that respond to visual targets in a hand-centered frame of reference have been found within various areas of the primate brain. We investigate how hand-centered visual representations may develop in a neural network model of the primate visual system called VisNet, when the model is trained on images of the hand seen against natural visual scenes. The simulations show how such neurons may develop through a biologically plausible process of unsupervised competitive learning and self-organization. In an advance on our previous work, the visual scenes consisted of multiple targets presented simultaneously with respect to the hand. Three experiments are presented. First, VisNet was trained with computerized images consisting of a realistic image of a hand and a variety of natural objects, presented in different textured backgrounds during training. The network was then tested with just one textured object near the hand in order to verify if the output cells were capable of building hand-centered representations with a single localized receptive field. We explain the underlying principles of the statistical decoupling that allows the output cells of the network to develop single localized receptive fields even when the network is trained with multiple objects. In a second simulation we examined how some of the cells with hand-centered receptive fields decreased their shape selectivity and started responding to a localized region of hand-centered space as the number of objects presented in overlapping locations during training increases. Lastly, we explored the same learning principles training the network with natural visual scenes collected by volunteers. These results provide an important step in showing how single, localized, hand-centered receptive fields could emerge under more ecologically realistic visual training conditions.

  17. The development of hand-centred visual representations in the primate brain: a computer modelling study using natural visual scenes.

    Directory of Open Access Journals (Sweden)

    Juan Manuel Galeazzi

    2015-12-01

    Full Text Available Neurons that respond to visual targets in a hand-centred frame of reference have been found within various areas of the primate brain. We investigate how hand-centred visual representations may develop in a neural network model of the primate visual system called VisNet, when the model is trained on images of the hand seen against natural visual scenes. The simulations show how such neurons may develop through a biologically plausible process of unsupervised competitive learning and self-organisation. In an advance on our previous work, the visual scenes consisted of multiple targets presented simultaneously with respect to the hand. Three experiments are presented. First, VisNet was trained with computerized images consisting of a realistic image of a hand and and a variety of natural objects, presented in different textured backgrounds during training. The network was then tested with just one textured object near the hand in order to verify if the output cells were capable of building hand-centered representations with a single localised receptive field. We explain the underlying principles of the statistical decoupling that allows the output cells of the network to develop single localised receptive fields even when the network is trained with multiple objects. In a second simulation we examined how some of the cells with hand-centred receptive fields decreased their shape selectivity and started responding to a localised region of hand-centred space as the number of objects presented in overlapping locations during training increases. Lastly, we explored the same learning principles training the network with natural visual scenes collected by volunteers. These results provide an important step in showing how single, localised, hand-centered receptive fields could emerge under more ecologically realistic visual training conditions.

  18. Scale-Free Brain Networks Based on the Event-Related Potential during Visual Spatial Attention

    Institute of Scientific and Technical Information of China (English)

    LI Ling; JIN Zhen-Lan

    2011-01-01

    @@ The human brain is thought of as one of the most complex dynamical systems in the universe.The network view of the dynamical system has emerged since the discovery of scale-free networks.Brain functional networks, which represent functional associations among brain regions, are extracted by measuring the temporal correlations from electroencephalogram data.We measure the topological properties of the brain functional network, including degree distribution, average degree, clustering coefficient and the shortest path length, to compare the networks of multi-channel event-related potential activity between visual spatial attention and unattention conditions.It is found that the degree distribution of the brain functional networks under both the conditions is a power law distribution, which reflects a scale-free property.Moreover, the scaling exponent of the attention condition is significantly smaller than that of the unattention condition.However, the degree distribution of equivalent random networks does not follow the power law distribution.In addition, the clustering coefficient of these random networks is smaller than those of brain networks, and the shortest path length of these random networks is large and comparable with those of brain networks.Our results, typical of scale-free networks, indicate that the scaling exponent of brain activity could reflect different cognitive processes.%The human brain is thought of as one of the most complex dynamical systems in the universe. The network view of the dynamical system has emerged since the discovery of scale-free networks. Brain functional networks, which represent functional associations among brain regions, are extracted by measuring the temporal correlations from electroencephalogram data. We measure the topological properties of the brain functional network, including degree distribution, average degree, clustering coefficient and the shortest path length, to compare the networks of multi-channel event

  19. Interaction of brain areas of visual and vestibular simultaneous activity with fMRI.

    Science.gov (United States)

    Della-Justina, Hellen M; Gamba, Humberto R; Lukasova, Katerina; Nucci-da-Silva, Mariana P; Winkler, Anderson M; Amaro, Edson

    2015-01-01

    Static body equilibrium is an essential requisite for human daily life. It is known that visual and vestibular systems must work together to support equilibrium. However, the relationship between these two systems is not fully understood. In this work, we present the results of a study which identify the interaction of brain areas that are involved with concurrent visual and vestibular inputs. The visual and the vestibular systems were individually and simultaneously stimulated, using flickering checkerboard (without movement stimulus) and galvanic current, during experiments of functional magnetic resonance imaging. Twenty-four right-handed and non-symptomatic subjects participated in this study. Single visual stimulation shows positive blood-oxygen-level-dependent (BOLD) responses (PBR) in the primary and associative visual cortices. Single vestibular stimulation shows PBR in the parieto-insular vestibular cortex, inferior parietal lobe, superior temporal gyrus, precentral gyrus and lobules V and VI of the cerebellar hemisphere. Simultaneous stimulation shows PBR in the middle and inferior frontal gyri and in the precentral gyrus. Vestibular- and somatosensory-related areas show negative BOLD responses (NBR) during simultaneous stimulation. NBR areas were also observed in the calcarine gyrus, lingual gyrus, cuneus and precuneus during simultaneous and single visual stimulations. For static visual and galvanic vestibular simultaneous stimulation, the reciprocal inhibitory visual-vestibular interaction pattern is observed in our results. The experimental results revealed interactions in frontal areas during concurrent visual-vestibular stimuli, which are affected by intermodal association areas in occipital, parietal, and temporal lobes.

  20. Impaired Visual Integration in Children with Traumatic Brain Injury: An Observational Study

    NARCIS (Netherlands)

    M. Königs (Marsh); W.D. Weeda (Wouter D.); L.W.E. Van Heurn (L.W. Ernest); R.J. Vermeulen (R. Jeroen); J.C. Goslings (Carel); J.S.K. Luitse (Jan S.K.); B.T. Poll-Thé (Bwee Tien); A. Beelen (Anita); M. Van Der Wees (Marleen); R.J.J.K. Kemps (Rachèl J.J.K.); C.E. Catsman-Berrevoets (Coriene); J. Oosterlaan (Jaap)

    2015-01-01

    textabstractBackground Axonal injury after traumatic brain injury (TBI) may cause impaired sensory integration. We aim to determine the effects of childhood TBI on visual integration in relation to general neurocognitive functioning. Methods We compared children aged 6-13 diagnosed with TBI (n = 103

  1. Rehabilitation regimes based upon psychophysical studies of prosthetic vision

    Science.gov (United States)

    Chen, S. C.; Suaning, G. J.; Morley, J. W.; Lovell, N. H.

    2009-06-01

    Human trials of prototype visual prostheses have successfully elicited visual percepts (phosphenes) in the visual field of implant recipients blinded through retinitis pigmentosa and age-related macular degeneration. Researchers are progressing rapidly towards a device that utilizes individual phosphenes as the elementary building blocks to compose a visual scene. This form of prosthetic vision is expected, in the near term, to have low resolution, large inter-phosphene gaps, distorted spatial distribution of phosphenes, restricted field of view, an eccentrically located phosphene field and limited number of expressible luminance levels. In order to fully realize the potential of these devices, there needs to be a training and rehabilitation program which aims to assist the prosthesis recipients to understand what they are seeing, and also to adapt their viewing habits to optimize the performance of the device. Based on the literature of psychophysical studies in simulated and real prosthetic vision, this paper proposes a comprehensive, theoretical training regime for a prosthesis recipient: visual search, visual acuity, reading, face/object recognition, hand-eye coordination and navigation. The aim of these tasks is to train the recipients to conduct visual scanning, eccentric viewing and reading, discerning low-contrast visual information, and coordinating bodily actions for visual-guided tasks under prosthetic vision. These skills have been identified as playing an important role in making prosthetic vision functional for the daily activities of their recipients.

  2. Visualization of nerve fiber orientation in gross histological sections of the human brain.

    Science.gov (United States)

    Axer, H; Berks, G; Keyserlingk, D G

    2000-12-01

    Diffusion weighted magnetic resonance imaging (DWMRI) allows visualization of the orientation of the nervous fibers in the living brain. For comparison, a method was developed to examine the orientation of fibers in histological sections of the human brain. Serial sections through the entire human brain were analyzed regarding fiber orientation using polarized light. Direction of fibers in the cutting plane was obtained by measuring the azimuth with the lowest intensity value at each point, and inclination of fibers in the section was evaluated using fuzzy logic approximations. Direction and inclination of fibers revealing their three-dimensional orientation were visualized by colored arrows mapped into the images. Using this procedure, various fiber tracts were identified (pyramidal tract, radiatio optica, radiatio acustica, arcuate fascicle, and 11 more). Intermingled fibers could be separated from each other. The orientation of the fiber tracts derived from polarized light microscopy was validated by confocal laser scanning microscopy in a defined volume of the internal capsule, where the fiber orientation was studied in four human brains. The polarization method visualizes the high degree of intermingled fiber bundles in the brain, so that distinct fiber pathways cannot be understood as solid, compact tracts: Neighbouring bundles of fibers can belong to different systems of fibers distinguishable by their orientation.

  3. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  4. The Visual Brain, Perception, and Depiction of Animals in Rock Art

    Directory of Open Access Journals (Sweden)

    Derek Hodgson

    2013-01-01

    Full Text Available Several aspects of the depiction of animals in rock art can be explained by certain perceptual correlates relating to the visual brain and evolutionary factors. Recent evidence from neuroscience and the visual brain not only corroborates this claim but provides important new findings that can help delineate which graphic features relate to biological/genetic criteria. In addition to highlighting how the insights from visual science and evolutionary studies can promote a greater understanding of the depictive strategies employed to portray animals, this paper will also explore ways in which the findings from these disciplines can be assimilated with semiotics that provide novel insights into the preference for depicting animals in a particular format over an extended period. The emphasis throughout is placed on dual-inheritance theory where culture and evolutionary determinants are seen as complementary.

  5. Linking brain to behavior for the visual perception of figures and objects.

    Science.gov (United States)

    Fesi, Jeremy D; Mendola, Janine D

    2013-11-01

    The dissociation of a figure from its background is an essential feat of visual perception, as it allows us to detect, recognize, and interact with shapes and objects in our environment. In order to understand how the human brain gives rise to the perception of figures, we here review experiments that explore the links between activity in visual cortex and performance of perceptual tasks related to figure perception. We organize our review according to a proposed model that attempts to contextualize figure processing within the more general framework of object processing in the brain. Overall, the current literature provides us with individual linking hypotheses as to cortical regions that are necessary for particular tasks related to figure perception. Attempts to reach a more complete understanding of how the brain instantiates figure and object perception, however, will have to consider the temporal interaction between the many regions involved, the details of which may vary widely across different tasks.

  6. Imaging studies in congenital anophthalmia reveal preservation of brain architecture in 'visual' cortex.

    Science.gov (United States)

    Bridge, Holly; Cowey, Alan; Ragge, Nicola; Watkins, Kate

    2009-12-01

    The functional specialization of the human brain means that many regions are dedicated to processing a single sensory modality. When a modality is absent, as in congenital total blindness, 'visual' regions can be reliably activated by non-visual stimuli. The connections underlying this functional adaptation, however, remain elusive. In this study, using structural and diffusion-weighted magnetic resonance imaging, we investigated the structural differences in the brains of six bilaterally anophthalmic subjects compared with sighted subjects. Surprisingly, the gross structural differences in the brains were small, even in the occipital lobe where only a small region of the primary visual cortex showed a bilateral reduction in grey matter volume in the anophthalmic subjects compared with controls. Regions of increased cortical thickness were apparent on the banks of the Calcarine sulcus, but not in the fundus. Subcortically, the white matter volume around the optic tract and internal capsule in anophthalmic subjects showed a large decrease, yet the optic radiation volume did not differ significantly. However, the white matter integrity, as measured with fractional anisotropy showed an extensive reduction throughout the brain in the anophthalmic subjects, with the greatest difference in the optic radiations. In apparent contradiction to the latter finding, the connectivity between the lateral geniculate nucleus and primary visual cortex measured with diffusion tractography did not differ between the two populations. However, these findings can be reconciled by a demonstration that at least some of the reduction in fractional anisotropy in the optic radiation is due to an increase in the strength of fibres crossing the radiations. In summary, the major changes in the 'visual' brain in anophthalmic subjects may be subcortical, although the evidence of decreased fractional anisotropy and increased crossing fibres could indicate considerable re-organization.

  7. Brain activity related to integrative processes in visual object recognition

    DEFF Research Database (Denmark)

    Gerlach, Christian; Aaside, C T; Humphreys, G W

    2002-01-01

    We report evidence from a PET activation study that the inferior occipital gyri (likely to include area V2) and the posterior parts of the fusiform and inferior temporal gyri are involved in the integration of visual elements into perceptual wholes (single objects). Of these areas, the fusiform...... with access to stored structural knowledge, was found with recognizable stimuli, but not with unrecognizable stimuli. This latter finding also indicates: (i) that subjects may not refrain from (automatically) identifying objects even if they only have to attend to the objects' global shape, and (ii......) that perceptual and memorial processes can be dissociated on both functional and anatomical grounds. No evidence was obtained for the involvement of the parietal lobes in the integration of single objects....

  8. Interactive 3D visualization of structural changes in the brain of a person with corticobasal syndrome

    Directory of Open Access Journals (Sweden)

    Claudia eHänel

    2014-05-01

    Full Text Available The visualization of the progression of brain tissue loss, which occurs in neurodegenerative diseases like corticobasal syndrome (CBS, is an important prerequisite to understand the course and the causes of this neurodegenerative disorder. Common workflows for visual analysis are often based on single 2D sections since in 3D visualizations more internally situated structures may be occluded by structures near the surface. The reduction of dimensions from 3D to 2D allows for an holistic view onto internal and external structures, but results in a loss of spatial information. Here, we present an application with two 3D visualization designs to resolve these challenges. First, in addition to the volume changes, the semi-transparent anatomy is displayed with an anatomical section and cortical areas for spatial orientation. Second, the principle of importance-driven volume rendering is adapted to give an unrestricted line-of-sight to relevant structures by means of a frustum-like cutout. To strengthen the benefits of the 3D visualization, we decided to provide the application next to standard desktop environments in immersive virtual environments with stereoscopic viewing as well. This improves the depth perception in general and in particular for the second design. Thus, the application presented in this work allows for aneasily comprehensible visual analysis of the extent of brain degeneration and the corresponding affected regions.

  9. Cholinergic enhancement of visual attention and neural oscillations in the human brain.

    Science.gov (United States)

    Bauer, Markus; Kluge, Christian; Bach, Dominik; Bradbury, David; Heinze, Hans Jochen; Dolan, Raymond J; Driver, Jon

    2012-03-06

    Cognitive processes such as visual perception and selective attention induce specific patterns of brain oscillations. The neurochemical bases of these spectral changes in neural activity are largely unknown, but neuromodulators are thought to regulate processing. The cholinergic system is linked to attentional function in vivo, whereas separate in vitro studies show that cholinergic agonists induce high-frequency oscillations in slice preparations. This has led to theoretical proposals that cholinergic enhancement of visual attention might operate via gamma oscillations in visual cortex, although low-frequency alpha/beta modulation may also play a key role. Here we used MEG to record cortical oscillations in the context of administration of a cholinergic agonist (physostigmine) during a spatial visual attention task in humans. This cholinergic agonist enhanced spatial attention effects on low-frequency alpha/beta oscillations in visual cortex, an effect correlating with a drug-induced speeding of performance. By contrast, the cholinergic agonist did not alter high-frequency gamma oscillations in visual cortex. Thus, our findings show that cholinergic neuromodulation enhances attentional selection via an impact on oscillatory synchrony in visual cortex, for low rather than high frequencies. We discuss this dissociation between high- and low-frequency oscillations in relation to proposals that lower-frequency oscillations are generated by feedback pathways within visual cortex.

  10. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia

    NARCIS (Netherlands)

    Langen, C.D.; White, T.; Ikram, M.A.; Vernooij, M.W.; Niessen, W.J.

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significan

  11. Scale-Free Brain Networks Based on the Event-Related Potential during Visual Spatial Attention

    Science.gov (United States)

    Li, Ling; Jin, Zhen-Lan

    2011-04-01

    The human brain is thought of as one of the most complex dynamical systems in the universe. The network view of the dynamical system has emerged since the discovery of scale-free networks. Brain functional networks, which represent functional associations among brain regions, are extracted by measuring the temporal correlations from electroencephalogram data. We measure the topological properties of the brain functional network, including degree distribution, average degree, clustering coefficient and the shortest path length, to compare the networks of multi-channel event-related potential activity between visual spatial attention and unattention conditions. It is found that the degree distribution of the brain functional networks under both the conditions is a power law distribution, which reflects a scale-free property. Moreover, the scaling exponent of the attention condition is significantly smaller than that of the unattention condition. However, the degree distribution of equivalent random networks does not follow the power law distribution. In addition, the clustering coefficient of these random networks is smaller than those of brain networks, and the shortest path length of these random networks is large and comparable with those of brain networks. Our results, typical of scale-free networks, indicate that the scaling exponent of brain activity could reflect different cognitive processes.

  12. Brain-computer interface based on generation of visual images.

    Directory of Open Access Journals (Sweden)

    Pavel Bobrov

    Full Text Available This paper examines the task of recognizing EEG patterns that correspond to performing three mental tasks: relaxation and imagining of two types of pictures: faces and houses. The experiments were performed using two EEG headsets: BrainProducts ActiCap and Emotiv EPOC. The Emotiv headset becomes widely used in consumer BCI application allowing for conducting large-scale EEG experiments in the future. Since classification accuracy significantly exceeded the level of random classification during the first three days of the experiment with EPOC headset, a control experiment was performed on the fourth day using ActiCap. The control experiment has shown that utilization of high-quality research equipment can enhance classification accuracy (up to 68% in some subjects and that the accuracy is independent of the presence of EEG artifacts related to blinking and eye movement. This study also shows that computationally-inexpensive bayesian classifier based on covariance matrix analysis yields similar classification accuracy in this problem as a more sophisticated Multi-class Common Spatial Patterns (MCSP classifier.

  13. Brain activity associated with translation from a visual to a symbolic representation in algebra and geometry.

    Science.gov (United States)

    Leikin, Mark; Waisman, Ilana; Shaul, Shelley; Leikin, Roza

    2014-03-01

    This paper presents a small part of a larger interdisciplinary study that investigates brain activity (using event related potential methodology) of male adolescents when solving mathematical problems of different types. The study design links mathematics education research with neurocognitive studies. In this paper we performed a comparative analysis of brain activity associated with the translation from visual to symbolic representations of mathematical objects in algebra and geometry. Algebraic tasks require translation from graphical to symbolic representation of a function, whereas tasks in geometry require translation from a drawing of a geometric figure to a symbolic representation of its property. The findings demonstrate that electrical activity associated with the performance of geometrical tasks is stronger than that associated with solving algebraic tasks. Additionally, we found different scalp topography of the brain activity associated with algebraic and geometric tasks. Based on these results, we argue that problem solving in algebra and geometry is associated with different patterns of brain activity.

  14. Objects and their icons in the brain: the neural correlates of visual concept formation.

    Science.gov (United States)

    Shin, Yong-Wook; Kwon, Jun Soo; Kwon, Ki Won; Gu, Bon Mi; Song, In Chan; Na, Dong Gyu; Park, Sohee

    2008-05-16

    We are constantly exposed to symbols such as traffic signs, emoticons in internet communication, or other abstract representations of objects as well as, of course, the written words. However, aside from the word reading, little is known about the way our brain responds when we read non-lexical iconic symbols. By using functional MRI, we found that the watching of icons recruited manifold brain areas including frontal and parietal cortices in addition to the temporo-occipital junction in the ventral pathway. Remarkably, the brain response for icons was contrasted with the response for corresponding concrete objects with the pattern of 'hyper-cortical and hypo-subcortical' brain activation. This neural underpinning might be called the neural correlates for visual concept formation.

  15. Functional divisions for visual processing in the central brain of flying Drosophila

    Science.gov (United States)

    Weir, Peter T.; Dickinson, Michael H.

    2015-01-01

    Although anatomy is often the first step in assigning functions to neural structures, it is not always clear whether architecturally distinct regions of the brain correspond to operational units. Whereas neuroarchitecture remains relatively static, functional connectivity may change almost instantaneously according to behavioral context. We imaged panneuronal responses to visual stimuli in a highly conserved central brain region in the fruit fly, Drosophila, during flight. In one substructure, the fan-shaped body, automated analysis revealed three layers that were unresponsive in quiescent flies but became responsive to visual stimuli when the animal was flying. The responses of these regions to a broad suite of visual stimuli suggest that they are involved in the regulation of flight heading. To identify the cell types that underlie these responses, we imaged activity in sets of genetically defined neurons with arborizations in the targeted layers. The responses of this collection during flight also segregated into three sets, confirming the existence of three layers, and they collectively accounted for the panneuronal activity. Our results provide an atlas of flight-gated visual responses in a central brain circuit. PMID:26324910

  16. 3D Data Mapping and Real-Time Experiment Control and Visualization in Brain Slices.

    Science.gov (United States)

    Navarro, Marco A; Hibbard, Jaime V K; Miller, Michael E; Nivin, Tyler W; Milescu, Lorin S

    2015-10-20

    Here, we propose two basic concepts that can streamline electrophysiology and imaging experiments in brain slices and enhance data collection and analysis. The first idea is to interface the experiment with a software environment that provides a 3D scene viewer in which the experimental rig, the brain slice, and the recorded data are represented to scale. Within the 3D scene viewer, the user can visualize a live image of the sample and 3D renderings of the recording electrodes with real-time position feedback. Furthermore, the user can control the instruments and visualize their status in real time. The second idea is to integrate multiple types of experimental data into a spatial and temporal map of the brain slice. These data may include low-magnification maps of the entire brain slice, for spatial context, or any other type of high-resolution structural and functional image, together with time-resolved electrical and optical signals. The entire data collection can be visualized within the 3D scene viewer. These concepts can be applied to any other type of experiment in which high-resolution data are recorded within a larger sample at different spatial and temporal coordinates.

  17. Electroencephalographic brain dynamics following manually responded visual targets.

    Directory of Open Access Journals (Sweden)

    Scott Makeig

    2004-06-01

    Full Text Available Scalp-recorded electroencephalographic (EEG signals produced by partial synchronization of cortical field activity mix locally synchronous electrical activities of many cortical areas. Analysis of event-related EEG signals typically assumes that poststimulus potentials emerge out of a flat baseline. Signals associated with a particular type of cognitive event are then assessed by averaging data from each scalp channel across trials, producing averaged event-related potentials (ERPs. ERP averaging, however, filters out much of the information about cortical dynamics available in the unaveraged data trials. Here, we studied the dynamics of cortical electrical activity while subjects detected and manually responded to visual targets, viewing signals retained in ERP averages not as responses of an otherwise silent system but as resulting from event-related alterations in ongoing EEG processes. We applied infomax independent component analysis to parse the dynamics of the unaveraged 31-channel EEG signals into maximally independent processes, then clustered the resulting processes across subjects by similarities in their scalp maps and activity power spectra, identifying nine classes of EEG processes with distinct spatial distributions and event-related dynamics. Coupled two-cycle postmotor theta bursts followed button presses in frontal midline and somatomotor clusters, while the broad postmotor "P300" positivity summed distinct contributions from several classes of frontal, parietal, and occipital processes. The observed event-related changes in local field activities, within and between cortical areas, may serve to modulate the strength of spike-based communication between cortical areas to update attention, expectancy, memory, and motor preparation during and after target recognition and speeded responding.

  18. REORGANIZATION OF VISUAL CALLOSAL CONNECTIONS FOLLOWING ALTERATIONS OF RETINAL INPUT AND BRAIN DAMAGE

    Directory of Open Access Journals (Sweden)

    LAURA RESTANI

    2016-11-01

    Full Text Available Vision is a very important sensory modality in humans. Visual disorders are numerous and arising from diverse and complex causes. Deficits in visual function are highly disabling from a social point of view and in addition cause a considerable economic burden. For all these reasons there is an intense effort by the scientific community to gather knowledge on visual deficit mechanisms and to find possible new strategies for recovery and treatment. In this review we focus on an important and sometimes neglected player of the visual function, the corpus callosum (CC. The CC is the major white matter structure in the brain and is involved in information processing between the two hemispheres. In particular, visual callosal connections interconnect homologous areas of visual cortices, binding together the two halves of the visual field. This interhemispheric communication plays a significant role in visual cortical output. Here, we will first review essential literature on the physiology of the callosal connections in normal vision. The available data support the view that the callosum contributes to both excitation and inhibition to the target hemisphere, with a dynamic adaptation to the strength of the incoming visual input. Next, we will focus on data showing how callosal connections may sense visual alterations and respond to the classical paradigm for the study of visual plasticity, i.e. monocular deprivation. This is a prototypical example of a model for the study of callosal plasticity in pathological conditions (e.g. strabismus and amblyopia characterized by unbalanced input from the two eyes. We will also discuss findings of callosal alterations in blind subjects. Noteworthy, we will discuss data showing that inter-hemispheric transfer mediates recovery of visual responsiveness following cortical damage. Finally, we will provide an overview of how callosal projections dysfunction could contribute to pathologies such as neglect and occipital

  19. How art changes your brain: differential effects of visual art production and cognitive art evaluation on functional brain connectivity.

    Science.gov (United States)

    Bolwerk, Anne; Mack-Andrick, Jessica; Lang, Frieder R; Dörfler, Arnd; Maihöfner, Christian

    2014-01-01

    Visual art represents a powerful resource for mental and physical well-being. However, little is known about the underlying effects at a neural level. A critical question is whether visual art production and cognitive art evaluation may have different effects on the functional interplay of the brain's default mode network (DMN). We used fMRI to investigate the DMN of a non-clinical sample of 28 post-retirement adults (63.71 years ±3.52 SD) before (T0) and after (T1) weekly participation in two different 10-week-long art interventions. Participants were randomly assigned to groups stratified by gender and age. In the visual art production group 14 participants actively produced art in an art class. In the cognitive art evaluation group 14 participants cognitively evaluated artwork at a museum. The DMN of both groups was identified by using a seed voxel correlation analysis (SCA) in the posterior cingulated cortex (PCC/preCUN). An analysis of covariance (ANCOVA) was employed to relate fMRI data to psychological resilience which was measured with the brief German counterpart of the Resilience Scale (RS-11). We observed that the visual art production group showed greater spatial improvement in functional connectivity of PCC/preCUN to the frontal and parietal cortices from T0 to T1 than the cognitive art evaluation group. Moreover, the functional connectivity in the visual art production group was related to psychological resilience (i.e., stress resistance) at T1. Our findings are the first to demonstrate the neural effects of visual art production on psychological resilience in adulthood.

  20. Rotationally Actuated Prosthetic Hand

    Science.gov (United States)

    Norton, William E.; Belcher, Jewell G., Jr.; Carden, James R.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand attached to end of remaining part of forearm and to upper arm just above elbow. Pincerlike fingers pushed apart to degree depending on rotation of forearm. Simpler in design, simpler to operate, weighs less, and takes up less space.

  1. Analysis of brain activity and response during monoscopic and stereoscopic visualization

    Science.gov (United States)

    Calore, Enrico; Folgieri, Raffaella; Gadia, Davide; Marini, Daniele

    2012-03-01

    Stereoscopic visualization in cinematography and Virtual Reality (VR) creates an illusion of depth by means of two bidimensional images corresponding to different views of a scene. This perceptual trick is used to enhance the emotional response and the sense of presence and immersivity of the observers. An interesting question is if and how it is possible to measure and analyze the level of emotional involvement and attention of the observers during a stereoscopic visualization of a movie or of a virtual environment. The research aims represent a challenge, due to the large number of sensorial, physiological and cognitive stimuli involved. In this paper we begin this research by analyzing possible differences in the brain activity of subjects during the viewing of monoscopic or stereoscopic contents. To this aim, we have performed some preliminary experiments collecting electroencephalographic (EEG) data of a group of users using a Brain- Computer Interface (BCI) during the viewing of stereoscopic and monoscopic short movies in a VR immersive installation.

  2. Left Brain vs. Right Brain: Findings on Visual Spatial Capacities and the Functional Neurology of Giftedness

    Science.gov (United States)

    Kalbfleisch, M. Layne; Gillmarten, Charles

    2013-01-01

    As neuroimaging technologies increase their sensitivity to assess the function of the human brain and results from these studies draw the attention of educators, it becomes paramount to identify misconceptions about what these data illustrate and how these findings might be applied to educational contexts. Some of these "neuromyths" have…

  3. Brain SPECT in mesial temporal lobe epilepsy: comparison between visual analysis and SPM (Statistical Parametric Mapping)

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Barbara Juarez; Ramos, Celso Dario; Santos, Allan Oliveira dos; Lima, Mariana da Cunha Lopes de; Camargo, Edwaldo Eduardo; Etchebehere, Elba Cristina Sa de Camargo, E-mail: juarezbarbara@hotmail.co [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Radiology; Min, Li Li; Cendes, Fernando [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Neurology

    2010-04-15

    Objective: to compare the accuracy of SPM and visual analysis of brain SPECT in patients with mesial temporal lobe epilepsy (MTLE). Method: interictal and ictal SPECTs of 22 patients with MTLE were performed. Visual analysis were performed in interictal (VISUAL(inter)) and ictal (VISUAL(ictal/inter)) studies. SPM analysis consisted of comparing interictal (SPM(inter)) and ictal SPECTs (SPM(ictal)) of each patient to control group and by comparing perfusion of temporal lobes in ictal and interictal studies among themselves (SPM(ictal/inter)). Results: for detection of the epileptogenic focus, the sensitivities were as follows: VISUAL(inter)=68%; VISUAL(ictal/inter)=100%; SPM(inter)=45%; SPM(ictal)=64% and SPM(ictal/inter)=77%. SPM was able to detect more areas of hyperperfusion and hypoperfusion. Conclusion: SPM did not improve the sensitivity to detect epileptogenic focus. However, SPM detected different regions of hypoperfusion and hyperperfusion and is therefore a helpful tool for better understand pathophysiology of seizures in MTLE. (author)

  4. How is visual salience computed in the brain? Insights from behaviour, neurobiology and modelling

    Science.gov (United States)

    Veale, Richard; Hafed, Ziad M.

    2017-01-01

    Inherent in visual scene analysis is a bottleneck associated with the need to sequentially sample locations with foveating eye movements. The concept of a ‘saliency map’ topographically encoding stimulus conspicuity over the visual scene has proven to be an efficient predictor of eye movements. Our work reviews insights into the neurobiological implementation of visual salience computation. We start by summarizing the role that different visual brain areas play in salience computation, whether at the level of feature analysis for bottom-up salience or at the level of goal-directed priority maps for output behaviour. We then delve into how a subcortical structure, the superior colliculus (SC), participates in salience computation. The SC represents a visual saliency map via a centre-surround inhibition mechanism in the superficial layers, which feeds into priority selection mechanisms in the deeper layers, thereby affecting saccadic and microsaccadic eye movements. Lateral interactions in the local SC circuit are particularly important for controlling active populations of neurons. This, in turn, might help explain long-range effects, such as those of peripheral cues on tiny microsaccades. Finally, we show how a combination of in vitro neurophysiology and large-scale computational modelling is able to clarify how salience computation is implemented in the local circuit of the SC. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044023

  5. Brain dynamic mechanisms on the visual attention scale with Chinese characters cues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The temporal dynamics in brain evoked by the scale of visual attention with the cues of Chinese characters were studied by recording event-related potentials (ERPs). With the fixed orientation of visual attention, 14 healthy young participants performed a search task in which the search array was preceded by Chinese characters cues, "大, 中, 小" (large, medium, small). 128 channels scalp ERPs were recorded to study the role of visual attention scale played in the visual spatial attention. The results showed that there was no significant difference in the ERP components evoked by the three Chinese characters cues except the inferoposterior N2 latency. The targets evoked P2, N2 amplitudes and latency have significant differences with the different cues of large, middle and small, while P1 and N1 components had no significant difference. The results suggested that the processing of scale of visual attention was mainly concerned with P2, N2 components, while the P1, N1 components were mainly related with the processing of visual orientation information.

  6. Toward high performance, weakly invasive brain computer interfaces using selective visual attention.

    Science.gov (United States)

    Rotermund, David; Ernst, Udo A; Mandon, Sunita; Taylor, Katja; Smiyukha, Yulia; Kreiter, Andreas K; Pawelzik, Klaus R

    2013-04-01

    Brain-computer interfaces have been proposed as a solution for paralyzed persons to communicate and interact with their environment. However, the neural signals used for controlling such prostheses are often noisy and unreliable, resulting in a low performance of real-world applications. Here we propose neural signatures of selective visual attention in epidural recordings as a fast, reliable, and high-performance control signal for brain prostheses. We recorded epidural field potentials with chronically implanted electrode arrays from two macaque monkeys engaged in a shape-tracking task. For single trials, we classified the direction of attention to one of two visual stimuli based on spectral amplitude, coherence, and phase difference in time windows fixed relative to stimulus onset. Classification performances reached up to 99.9%, and the information about attentional states could be transferred at rates exceeding 580 bits/min. Good classification can already be achieved in time windows as short as 200 ms. The classification performance changed dynamically over the trial and modulated with the task's varying demands for attention. For all three signal features, the information about the direction of attention was contained in the γ-band. The most informative feature was spectral amplitude. Together, these findings establish a novel paradigm for constructing brain prostheses as, for example, virtual spelling boards, promising a major gain in performance and robustness for human brain-computer interfaces.

  7. ViSimpl: Multi-View Visual Analysis of Brain Simulation Data

    Science.gov (United States)

    Galindo, Sergio E.; Toharia, Pablo; Robles, Oscar D.; Pastor, Luis

    2016-01-01

    After decades of independent morphological and functional brain research, a key point in neuroscience nowadays is to understand the combined relationships between the structure of the brain and its components and their dynamics on multiple scales, ranging from circuits of neurons at micro or mesoscale to brain regions at macroscale. With such a goal in mind, there is a vast amount of research focusing on modeling and simulating activity within neuronal structures, and these simulations generate large and complex datasets which have to be analyzed in order to gain the desired insight. In such context, this paper presents ViSimpl, which integrates a set of visualization and interaction tools that provide a semantic view of brain data with the aim of improving its analysis procedures. ViSimpl provides 3D particle-based rendering that allows visualizing simulation data with their associated spatial and temporal information, enhancing the knowledge extraction process. It also provides abstract representations of the time-varying magnitudes supporting different data aggregation and disaggregation operations and giving also focus and context clues. In addition, ViSimpl tools provide synchronized playback control of the simulation being analyzed. Finally, ViSimpl allows performing selection and filtering operations relying on an application called NeuroScheme. All these views are loosely coupled and can be used independently, but they can also work together as linked views, both in centralized and distributed computing environments, enhancing the data exploration and analysis procedures. PMID:27774062

  8. Discovering anatomical patterns with pathological meaning by clustering of visual primitives in structural brain MRI

    Science.gov (United States)

    Leon, Juan; Pulido, Andrea; Romero, Eduardo

    2015-01-01

    Computational anatomy is a subdiscipline of the anatomy that studies macroscopic details of the human body structure using a set of automatic techniques. Different reference systems have been developed for brain mapping and morphometry in functional and structural studies. Several models integrate particular anatomical regions to highlight pathological patterns in structural brain MRI, a really challenging task due to the complexity, variability, and nonlinearity of the human brain anatomy. In this paper, we present a strategy that aims to find anatomical regions with pathological meaning by using a probabilistic analysis. Our method starts by extracting visual primitives from brain MRI that are partitioned into small patches and which are then softly clustered, forming different regions not necessarily connected. Each of these regions is described by a co- occurrence histogram of visual features, upon which a probabilistic semantic analysis is used to find the underlying structure of the information, i.e., separated regions by their low level similarity. The proposed approach was tested with the OASIS data set which includes 69 Alzheimer's disease (AD) patients and 65 healthy subjects (NC).

  9. A Multi-facetted Visual Analytics Tool for Exploratory Analysis of Human Brain and Function Datasets.

    Science.gov (United States)

    Angulo, Diego A; Schneider, Cyril; Oliver, James H; Charpak, Nathalie; Hernandez, Jose T

    2016-01-01

    Brain research typically requires large amounts of data from different sources, and often of different nature. The use of different software tools adapted to the nature of each data source can make research work cumbersome and time consuming. It follows that data is not often used to its fullest potential thus limiting exploratory analysis. This paper presents an ancillary software tool called BRAVIZ that integrates interactive visualization with real-time statistical analyses, facilitating access to multi-facetted neuroscience data and automating many cumbersome and error-prone tasks required to explore such data. Rather than relying on abstract numerical indicators, BRAVIZ emphasizes brain images as the main object of the analysis process of individuals or groups. BRAVIZ facilitates exploration of trends or relationships to gain an integrated view of the phenomena studied, thus motivating discovery of new hypotheses. A case study is presented that incorporates brain structure and function outcomes together with different types of clinical data.

  10. Healthy children show gender differences in correlations between nonverbal cognitive ability and brain activation during visual perception.

    Science.gov (United States)

    Asano, Kohei; Taki, Yasuyuki; Hashizume, Hiroshi; Sassa, Yuko; Thyreau, Benjamin; Asano, Michiko; Takeuchi, Hikaru; Kawashima, Ryuta

    2014-08-08

    Humans perceive textual and nontextual information in visual perception, and both depend on language. In childhood education, students exhibit diverse perceptual abilities, such that some students process textual information better and some process nontextual information better. These predispositions involve many factors, including cognitive ability and learning preference. However, the relationship between verbal and nonverbal cognitive abilities and brain activation during visual perception has not yet been examined in children. We used functional magnetic resonance imaging to examine the relationship between nonverbal and verbal cognitive abilities and brain activation during nontextual visual perception in large numbers of children. A significant positive correlation was found between nonverbal cognitive abilities and brain activation in the right temporoparietal junction, which is thought to be related to attention reorienting. This significant positive correlation existed only in boys. These findings suggested that male brain activation differed from female brain activation, and that this depended on individual cognitive processes, even if there was no gender difference in behavioral performance.

  11. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.

    2015-04-01

    Full Text Available This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.

  12. DARPA Revolutionizing Prosthetics 2009

    Science.gov (United States)

    2009-01-01

    therapeutic applications  System performance validation and design compliance  End-to-end interactive simulation  Acquires control signals ( myoelectric ...Cortical Control for Hand Movement CalTech • Higher Cortex Signal /Intent Extraction Otto Bock • Prosthetic Components • Control Bus Architecture...Clinical Support APL • Program Management • System Engineering & Integration • Signal & Image processing • Virtual Reality & Controls RIC • Virtual

  13. Magnets in prosthetic dentistry.

    Science.gov (United States)

    Riley, M A; Walmsley, A D; Harris, I R

    2001-08-01

    Magnetic retention is a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This review chronicles the development of magnets in dentistry and summarizes future research in their use. The literature was researched by using the Science Citation Index and Compendex Web from 1981 to 2000. Articles published before 1981 were hand researched from citations in other publications. Articles that discussed the use of magnets in relation to prosthetic dentistry were selected.

  14. Visualization

    OpenAIRE

    Balon, Andreja

    1990-01-01

    The present thesis entails the field of visualization which is divided into visualization along traditional lines and visualization in computer science. As the psychological aspect of image is of vital importance for visualization, it is shortly described in the beginning. Visualization in computer science is divided into three main fields: scientific visualization, program visualization and visual programming. An explanation and examples of approach to applications are given for each field....

  15. Broad-Band Visually Evoked Potentials: Re(convolution in Brain-Computer Interfacing.

    Directory of Open Access Journals (Sweden)

    Jordy Thielen

    Full Text Available Brain-Computer Interfaces (BCIs allow users to control devices and communicate by using brain activity only. BCIs based on broad-band visual stimulation can outperform BCIs using other stimulation paradigms. Visual stimulation with pseudo-random bit-sequences evokes specific Broad-Band Visually Evoked Potentials (BBVEPs that can be reliably used in BCI for high-speed communication in speller applications. In this study, we report a novel paradigm for a BBVEP-based BCI that utilizes a generative framework to predict responses to broad-band stimulation sequences. In this study we designed a BBVEP-based BCI using modulated Gold codes to mark cells in a visual speller BCI. We defined a linear generative model that decomposes full responses into overlapping single-flash responses. These single-flash responses are used to predict responses to novel stimulation sequences, which in turn serve as templates for classification. The linear generative model explains on average 50% and up to 66% of the variance of responses to both seen and unseen sequences. In an online experiment, 12 participants tested a 6 × 6 matrix speller BCI. On average, an online accuracy of 86% was reached with trial lengths of 3.21 seconds. This corresponds to an Information Transfer Rate of 48 bits per minute (approximately 9 symbols per minute. This study indicates the potential to model and predict responses to broad-band stimulation. These predicted responses are proven to be well-suited as templates for a BBVEP-based BCI, thereby enabling communication and control by brain activity only.

  16. Intrinsic activity in the fly brain gates visual information during behavioral choices.

    Directory of Open Access Journals (Sweden)

    Shiming Tang

    Full Text Available The small insect brain is often described as an input/output system that executes reflex-like behaviors. It can also initiate neural activity and behaviors intrinsically, seen as spontaneous behaviors, different arousal states and sleep. However, less is known about how intrinsic activity in neural circuits affects sensory information processing in the insect brain and variability in behavior. Here, by simultaneously monitoring Drosophila's behavioral choices and brain activity in a flight simulator system, we identify intrinsic activity that is associated with the act of selecting between visual stimuli. We recorded neural output (multiunit action potentials and local field potentials in the left and right optic lobes of a tethered flying Drosophila, while its attempts to follow visual motion (yaw torque were measured by a torque meter. We show that when facing competing motion stimuli on its left and right, Drosophila typically generate large torque responses that flip from side to side. The delayed onset (0.1-1 s and spontaneous switch-like dynamics of these responses, and the fact that the flies sometimes oppose the stimuli by flying straight, make this behavior different from the classic steering reflexes. Drosophila, thus, seem to choose one stimulus at a time and attempt to rotate toward its direction. With this behavior, the neural output of the optic lobes alternates; being augmented on the side chosen for body rotation and suppressed on the opposite side, even though the visual input to the fly eyes stays the same. Thus, the flow of information from the fly eyes is gated intrinsically. Such modulation can be noise-induced or intentional; with one possibility being that the fly brain highlights chosen information while ignoring the irrelevant, similar to what we know to occur in higher animals.

  17. Development of prosthetic skin

    Science.gov (United States)

    Kilaru, Rohit

    The objective of this research was to embed tactile sensors in polyimides. This novel method could be utilized to realize prosthetic skin for sensing different kinds of mechanical stimuli. Tactile sensors have an increasing demand in medical sectors: upper and lower-limb prosthetics and in the industrial sectors: robot end-effectors, grippers and manipulators. The sensors developed are targeted for prosthetic arm tactile sensing applications. Current work presents piezoresistive differential pressure sensors fabricated on flexible polyimide film or substrate. A unique technique to bond a flexible superstrate polyimide layer to a MEMS tactile sensor array is presented in this thesis. The sensor is made of aluminium oxide membrane layer with nichrome piezoresistors as the half-Wheatstone bridge elements. Four different types of sensor designs have been characterized to obtain gauge factor of thin film nichrome. The sensor arrays with and without the superstrate film were simulated for obtaining the maximum stress, average strain and deflection of the membrane. The maximum change in output voltage was 0.8 mV. The gauge factors calculated for tactile sensor with superstrate range between 2.2 to 7.8 and without superstrate range 1.5 to 5.7.

  18. Visual pop-out in barn owls: Human-like behavior in the avian brain.

    Science.gov (United States)

    Orlowski, Julius; Beissel, Christian; Rohn, Friederike; Adato, Yair; Wagner, Hermann; Ben-Shahar, Ohad

    2015-01-01

    Visual pop-out is a phenomenon by which the latency to detect a target in a scene is independent of the number of other elements, the distractors. Pop-out is an effective visual-search guidance that occurs typically when the target is distinct in one feature from the distractors, thus facilitating fast detection of predators or prey. However, apart from studies on primates, pop-out has been examined in few species and demonstrated thus far in rats, archer fish, and pigeons only. To fill this gap, here we study pop-out in barn owls. These birds are a unique model system for such exploration because their lack of eye movements dictates visual behavior dominated by head movements. Head saccades and interspersed fixation periods can therefore be tracked and analyzed with a head-mounted wireless microcamera--the OwlCam. Using this methodology we confronted two owls with scenes containing search arrays of one target among varying numbers (15-63) of similar looking distractors. We tested targets distinct either by orientation (Experiment 1) or luminance contrast (Experiment 2). Search time and the number of saccades until the target was fixated remained largely independent of the number of distractors in both experiments. This suggests that barn owls can exhibit pop-out during visual search, thus expanding the group of species and brain structures that can cope with this fundamental visual behavior. The utility of our automatic analysis method is further discussed for other species and scientific questions.

  19. Connecting art and the brain: an artist’s perspective on visual indeterminacy

    Directory of Open Access Journals (Sweden)

    Robert ePepperell

    2011-08-01

    Full Text Available In this article I will discuss the intersection between art and neuroscience from the perspective of a practicing artist. I have collaborated on several scientific studies into the effects of art on the brain and behaviour, looking in particular at the phenomenon of ‘visual indeterminacy’. This is a perceptual state in which subjects fail to recognise objects from visual cues. I will look at the background to this phenomenon, and show how various artists have exploited its effect through the history of art. My own attempts to create indeterminate images will be discussed, including some of the technical problems I faced in trying to manipulate the viewer’s perceptual state through paintings. Visual indeterminacy is not widely studied in neuroscience, although references to it can be found in the literature on visual agnosia and object recognition. I will briefly review some of this work and show how my attempts to understand the science behind visual indeterminacy led me to collaborate with psychophysicists and neuroscientists. After reviewing this work, I will discuss the conclusions I have drawn from its findings and consider the problem of how best to integrate neuroscientific methods with artistic knowledge to create truly interdisciplinary approach.

  20. 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

  1. Connecting Art and the Brain: An Artist's Perspective on Visual Indeterminacy.

    Science.gov (United States)

    Pepperell, Robert

    2011-01-01

    In this article I will discuss the intersection between art and neuroscience from the perspective of a practicing artist. I have collaborated on several scientific studies into the effects of art on the brain and behavior, looking in particular at the phenomenon of "visual indeterminacy." This is a perceptual state in which subjects fail to recognize objects from visual cues. I will look at the background to this phenomenon, and show how various artists have exploited its effect through the history of art. My own attempts to create indeterminate images will be discussed, including some of the technical problems I faced in trying to manipulate the viewer's perceptual state through paintings. Visual indeterminacy is not widely studied in neuroscience, although references to it can be found in the literature on visual agnosia and object recognition. I will briefly review some of this work and show how my attempts to understand the science behind visual indeterminacy led me to collaborate with psychophysicists and neuroscientists. After reviewing this work, I will discuss the conclusions I have drawn from its findings and consider the problem of how best to integrate neuroscientific methods with artistic knowledge to create truly interdisciplinary approach.

  2. Upper extremity amputations and prosthetics.

    Science.gov (United States)

    Ovadia, Steven A; Askari, Morad

    2015-02-01

    Upper extremity amputations are most frequently indicated by severe traumatic injuries. The location of the injury will determine the level of amputation. Preservation of extremity length is often a goal. The amputation site will have important implications on the functional status of the patient and options for prosthetic reconstruction. Advances in amputation techniques and prosthetic reconstructions promote improved quality of life. In this article, the authors review the principles of upper extremity amputation, including techniques, amputation sites, and prosthetic reconstructions.

  3. A Brain Computer Interface for Robust Wheelchair Control Application Based on Pseudorandom Code Modulated Visual Evoked Potential

    DEFF Research Database (Denmark)

    Mohebbi, Ali; Engelsholm, Signe K.D.; Puthusserypady, Sadasivan;

    2015-01-01

    In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudorandom code modulated Visual Evoked Potentials (c-VEPs). The visual stimuli in the scheme were generated based on the Gold code...

  4. Visual Field Function in School-Aged Children with Spastic Unilateral Cerebral Palsy Related to Different Patterns of Brain Damage

    Science.gov (United States)

    Jacobson, Lena; Rydberg, Agneta; Eliasson, Ann-Christin; Kits, Annika; Flodmark, Olof

    2010-01-01

    Aim: To relate visual field function to brain morphology in children with unilateral cerebral palsy (CP). Method: Visual field function was assessed using the confrontation technique and Goldmann perimetry in 29 children (15 males, 14 females; age range 7-17y, median age 11y) with unilateral CP classified at Gross Motor Function Classification…

  5. Processing of visual semantic information to concrete words: temporal dynamics and neural mechanisms indicated by event-related brain potentials

    NARCIS (Netherlands)

    Schie, H.T. van; Wijers, A.A.; Mars, R.B.; Benjamins, J.S.; Stowe, L.A.

    2005-01-01

    Event-related brain potentials were used to study the retrieval of visual semantic information to concrete words, and to investigate possible structural overlap between visual object working memory and concreteness effects in word processing. Subjects performed an object working memory task that inv

  6. Processing of visual semantic information to concrete words : temporal dynamics and neural mechanisms indicated by event-related brain potentials

    NARCIS (Netherlands)

    van Schie, HT; Wijers, AA; Mars, RB; Benjamins, JS; Stowe, LA; Mars, Ruben

    2005-01-01

    Event-related brain potentials were used to study the retrieval of visual semantic information to concrete words, and to investigate possible structural overlap between visual object working memory and concreteness effects in word processing. Subjects performed an object working memory task that inv

  7. Asymmetrical Brain Activity Induced by Voluntary Spatial Attention Depends on the Visual Hemifield: A Functional Near-Infrared Spectroscopy Study

    Science.gov (United States)

    Harasawa, Masamitsu; Shioiri, Satoshi

    2011-01-01

    The effect of the visual hemifield to which spatial attention was oriented on the activities of the posterior parietal and occipital visual cortices was examined using functional near-infrared spectroscopy in order to investigate the neural substrates of voluntary visuospatial attention. Our brain imaging data support the theory put forth in a…

  8. Role of inter-hemispheric transfer in generating visual evoked potentials in V1-damaged brain hemispheres.

    Science.gov (United States)

    Kavcic, Voyko; Triplett, Regina L; Das, Anasuya; Martin, Tim; Huxlin, Krystel R

    2015-02-01

    Partial cortical blindness is a visual deficit caused by unilateral damage to the primary visual cortex, a condition previously considered beyond hopes of rehabilitation. However, recent data demonstrate that patients may recover both simple and global motion discrimination following intensive training in their blind field. The present experiments characterized motion-induced neural activity of cortically blind (CB) subjects prior to the onset of visual rehabilitation. This was done to provide information about visual processing capabilities available to mediate training-induced visual improvements. Visual Evoked Potentials (VEPs) were recorded from two experimental groups consisting of 9 CB subjects and 9 age-matched, visually-intact controls. VEPs were collected following lateralized stimulus presentation to each of the 4 visual field quadrants. VEP waveforms were examined for both stimulus-onset (SO) and motion-onset (MO) related components in postero-lateral electrodes. While stimulus presentation to intact regions of the visual field elicited normal SO-P1, SO-N1, SO-P2 and MO-N2 amplitudes and latencies in contralateral brain regions of CB subjects, these components were not observed contralateral to stimulus presentation in blind quadrants of the visual field. In damaged brain hemispheres, SO-VEPs were only recorded following stimulus presentation to intact visual field quadrants, via inter-hemispheric transfer. MO-VEPs were only recorded from damaged left brain hemispheres, possibly reflecting a native left/right asymmetry in inter-hemispheric connections. The present findings suggest that damaged brain hemispheres contain areas capable of responding to visual stimulation. However, in the absence of training or rehabilitation, these areas only generate detectable VEPs in response to stimulation of the intact hemifield of vision.

  9. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia

    OpenAIRE

    Langen, Carolyn D.; Tonya White; Arfan Ikram, M.; Vernooij, Meike W.; Niessen, Wiro J.

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationshi...

  10. Trans3D: a free tool for dynamical visualization of EEG activity transmission in the brain.

    Science.gov (United States)

    Blinowski, Grzegorz; Kamiński, Maciej; Wawer, Dariusz

    2014-08-01

    The problem of functional connectivity in the brain is in the focus of attention nowadays, since it is crucial for understanding information processing in the brain. A large repertoire of measures of connectivity have been devised, some of them being capable of estimating time-varying directed connectivity. Hence, there is a need for a dedicated software tool for visualizing the propagation of electrical activity in the brain. To this aim, the Trans3D application was developed. It is an open access tool based on widely available libraries and supporting both Windows XP/Vista/7(™), Linux and Mac environments. Trans3D can create animations of activity propagation between electrodes/sensors, which can be placed by the user on the scalp/cortex of a 3D model of the head. Various interactive graphic functions for manipulating and visualizing components of the 3D model and input data are available. An application of the Trans3D tool has helped to elucidate the dynamics of the phenomena of information processing in motor and cognitive tasks, which otherwise would have been very difficult to observe. Trans3D is available at: http://www.eeg.pl/.

  11. Visual Impairment

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Visual Impairment KidsHealth > For Teens > Visual Impairment Print A ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  12. A Case Report of Unilateral Severe Visual Loss Along with Bilateral Optic Disc Cupping Secondary to Metastatic Brain Tumor

    Directory of Open Access Journals (Sweden)

    M Mahdavi

    2006-07-01

    Full Text Available Purpose: To report a case of unilateral severe visual loss and bilateral optic disc cupping secondary to brain metastasis of bronchogenic carcinoma Patient and findings: A 48 year-old woman presented with severe visual loss of left eye without redness or pain or any systemic findings .Clinical findings included decreased visual acuity of left eye to 4 m CF and (+3 positive Marcus-Gunn reflex .There was asymmetric optic disc cupping associated with visual field defect in left eye The neurologic investigations showed a secondary metastatic tumor in the brain from bronchogenic carcinoma. Conclusion: Before making a diagnosis of normal -tension glaucoma in asymmetric optic disc cupping and normal intraocular pressure, ophthalmologists should rule out neurologic defects and brain tumors.

  13. Visual encoding and fixation target selection in free viewing: presaccadic brain potentials

    Science.gov (United States)

    Nikolaev, Andrey R.; Jurica, Peter; Nakatani, Chie; Plomp, Gijs; van Leeuwen, Cees

    2013-01-01

    In scrutinizing a scene, the eyes alternate between fixations and saccades. During a fixation, two component processes can be distinguished: visual encoding and selection of the next fixation target. We aimed to distinguish the neural correlates of these processes in the electrical brain activity prior to a saccade onset. Participants viewed color photographs of natural scenes, in preparation for a change detection task. Then, for each participant and each scene we computed an image heat map, with temperature representing the duration and density of fixations. The temperature difference between the start and end points of saccades was taken as a measure of the expected task-relevance of the information concentrated in specific regions of a scene. Visual encoding was evaluated according to whether subsequent change was correctly detected. Saccades with larger temperature difference were more likely to be followed by correct detection than ones with smaller temperature differences. The amplitude of presaccadic activity over anterior brain areas was larger for correct detection than for detection failure. This difference was observed for short “scrutinizing” but not for long “explorative” saccades, suggesting that presaccadic activity reflects top-down saccade guidance. Thus, successful encoding requires local scanning of scene regions which are expected to be task-relevant. Next, we evaluated fixation target selection. Saccades “moving up” in temperature were preceded by presaccadic activity of higher amplitude than those “moving down”. This finding suggests that presaccadic activity reflects attention deployed to the following fixation location. Our findings illustrate how presaccadic activity can elucidate concurrent brain processes related to the immediate goal of planning the next saccade and the larger-scale goal of constructing a robust representation of the visual scene. PMID:23818877

  14. Visual encoding and fixation target selection in free viewing: presaccadic brain potentials

    Directory of Open Access Journals (Sweden)

    Andrey R Nikolaev

    2013-06-01

    Full Text Available In scrutinizing a scene, the eyes alternate between fixations and saccades. During a fixation, two component processes can be distinguished: visual encoding and selection of the next fixation target. We aimed to distinguish the neural correlates of these processes in the electrical brain activity prior to a saccade onset. Participants viewed color photographs of natural scenes, in preparation for a change detection task. Then, for each participant and each scene we computed an image heat map, with temperature representing the duration and density of fixations. The temperature difference between the start and end points of saccades was taken as a measure of the expected task-relevance of the information concentrated in specific regions of a scene. Visual encoding was evaluated according to whether subsequent change was correctly detected. Saccades with larger temperature difference were more likely to be followed by correct detection than ones with smaller temperature differences. The amplitude of presaccadic activity over anterior brain areas was larger for correct detection than for detection failure. This difference was observed for short scrutinizing but not for long explorative saccades, suggesting that presaccadic activity reflects top-down saccade guidance. Thus, successful encoding requires local scanning of scene regions which are expected to be task-relevant. Next, we evaluated fixation target selection. Saccades moving up in temperature were preceded by presaccadic activity of higher amplitude than those moving down. This finding suggests that presaccadic activity reflects attention deployed to the following fixation location. Our findings illustrate how presaccadic activity can elucidate concurrent brain processes related to the immediate goal of planning the next saccade and the larger-scale goal of constructing a robust representation of the visual scene.

  15. Analysis and visualization of cell movement in the developing zebrafish brain.

    Science.gov (United States)

    Langenberg, Tobias; Dracz, Tadeusz; Oates, Andrew C; Heisenberg, Carl-Philip; Brand, Michael

    2006-04-01

    Detailed reconstruction of the spatiotemporal history of embryonic cells is key to understanding tissue formation processes but is often complicated by the large number of cells involved, particularly so in vertebrates. Through a combination of high-resolution time-lapse lineage tracing and antibody staining, we have analyzed the movement of mesencephalic and metencephalic cell populations in the early zebrafish embryo. To facilitate the analysis of our cell tracking data, we have created TracePilot, a software tool that allows interactive manipulation and visualization of tracking data. We demonstrate its utility by showing novel visualizations of cell movement in the developing zebrafish brain. TracePilot (http://www.mpi-cbg.de/tracepilot) is Java-based, available free of charge, and has a program structure that allows the incorporation of additional analysis tools.

  16. Differential maturation of brain signal complexity in the human auditory and visual system

    Directory of Open Access Journals (Sweden)

    Sarah Lippe

    2009-11-01

    Full Text Available Brain development carries with it a large number of structural changes at the local level which impact on the functional interactions of distributed neuronal networks for perceptual processing. Such changes enhance information processing capacity, which can be indexed by estimation of neural signal complexity. Here, we show that during development, EEG signal complexity increases from one month to 5 years of age in response to auditory and visual stimulation. However, the rates of change in complexity were not equivalent for the two responses. Infants’ signal complexity for the visual condition was greater than auditory signal complexity, whereas adults showed the same level of complexity to both types of stimuli. The differential rates of complexity change may reflect a combination of innate and experiential factors on the structure and function of the two sensory systems.

  17. A 3-D visualization method for image-guided brain surgery.

    Science.gov (United States)

    Bourbakis, N G; Awad, M

    2003-01-01

    This paper deals with a 3D methodology for brain tumor image-guided surgery. The methodology is based on development of a visualization process that mimics the human surgeon behavior and decision-making. In particular, it originally constructs a 3D representation of a tumor by using the segmented version of the 2D MRI images. Then it develops an optimal path for the tumor extraction based on minimizing the surgical effort and penetration area. A cost function, incorporated in this process, minimizes the damage surrounding healthy tissues taking into consideration the constraints of a new snake-like surgical tool proposed here. The tumor extraction method presented in this paper is compared with the ordinary method used on brain surgery, which is based on a straight-line based surgical tool. Illustrative examples based on real simulations present the advantages of the 3D methodology proposed here.

  18. The encoding of temporally irregular and regular visual patterns in the human brain.

    Directory of Open Access Journals (Sweden)

    Semir Zeki

    Full Text Available In the work reported here, we set out to study the neural systems that detect predictable temporal patterns and departures from them. We used functional magnetic resonance imaging (fMRI to locate activity in the brains of subjects when they viewed temporally regular and irregular patterns produced by letters, numbers, colors and luminance. Activity induced by irregular sequences was located within dorsolateral prefrontal cortex, including an area that was responsive to irregular patterns regardless of the type of visual stimuli producing them. Conversely, temporally regular arrangements resulted in activity in the right frontal lobe (medial frontal gyrus, in the left orbito-frontal cortex and in the left pallidum. The results show that there is an abstractive system in the brain for detecting temporal irregularity, regardless of the source producing it.

  19. Steady State Visual Evoked Potential Based Brain-Computer Interface for Cognitive Assessment

    DEFF Research Database (Denmark)

    Westergren, Nicolai; Bendtsen, Rasmus L.; Kjær, Troels W.;

    2016-01-01

    decline is important. Cognitive decline may be detected using fullyautomated computerized assessment. Such systems will provide inexpensive and widely available screenings of cognitive ability. The aim of this pilot study is to develop a real time steady state visual evoked potential (SSVEP) based brain-computer...... interface (BCI) for neurological cognitive assessment. It is intended for use by patients who suffer from diseases impairing their motor skills, but are still able to control their gaze. Results are based on 11 healthy test subjects. The system performance have an average accuracy of 100% ± 0%. The test...

  20. [Effect of sleep deprivation on visual evoked potentials and brain stem auditory evoked potentials in epileptics].

    Science.gov (United States)

    Urumova, L T; Kovalenko, G A; Tsunikov, A I; Sumskiĭ, L I

    1984-01-01

    The article reports on the first study of the evoked activity of the brain in epileptic patients (n = 20) following sleep deprivation. An analysis of the data obtained has revealed a tendency to the shortening of the peak latent intervals of visual evoked potentials in the range of 100-200 mu sec and the V component and the interpeak interval III-V of evoked auditory trunk potentials in patients with temporal epilepsy. The phenomenon may indicate the elimination of stabilizing control involving the specific conductive pathways and, possibly, an accelerated conduction of a specific sensor signal.

  1. Thermoplastics for prosthetic applications.

    Science.gov (United States)

    Lawrence, R B; Davies, R M

    1981-10-01

    The rapid and accurate thermoforming of plastics for prosthetic applications has been the subject of considerable research and development by the Bioengineering Centre. This paper outlines the progress in the general concepts that have been effected to date. The original below knee (B/K) socket vacuum forming technique has been extended to above knee (A/K) and supracondylar cases, and there have been developments in rotational casting technology. The work is necessarily based on a sound understanding of the properties of the materials concerned and of the associated manufacturing processes. The contribution of the Bioengineering Centre is outlined together with summaries of collaborative work carried out with other organizations.

  2. Retinal prosthetics, optogenetics, and chemical photoswitches.

    Science.gov (United States)

    Marc, Robert; Pfeiffer, Rebecca; Jones, Bryan

    2014-10-15

    Three technologies have emerged as therapies to restore light sensing to profoundly blind patients suffering from late-stage retinal degenerations: (1) retinal prosthetics, (2) optogenetics, and (3) chemical photoswitches. Prosthetics are the most mature and the only approach in clinical practice. Prosthetic implants require complex surgical intervention and provide only limited visual resolution but can potentially restore navigational ability to many blind patients. Optogenetics uses viral delivery of type 1 opsin genes from prokaryotes or eukaryote algae to restore light responses in survivor neurons. Targeting and expression remain major problems, but are potentially soluble. Importantly, optogenetics could provide the ultimate in high-resolution vision due to the long persistence of gene expression achieved in animal models. Nevertheless, optogenetics remains challenging to implement in human eyes with large volumes, complex disease progression, and physical barriers to viral penetration. Now, a new generation of photochromic ligands or chemical photoswitches (azobenzene-quaternary ammonium derivatives) can be injected into a degenerated mouse eye and, in minutes to hours, activate light responses in neurons. These photoswitches offer the potential for rapidly and reversibly screening the vision restoration expected in an individual patient. Chemical photoswitch variants that persist in the cell membrane could make them a simple therapy of choice, with resolution and sensitivity equivalent to optogenetics approaches. A major complexity in treating retinal degenerations is retinal remodeling: pathologic network rewiring, molecular reprogramming, and cell death that compromise signaling in the surviving retina. Remodeling forces a choice between upstream and downstream targeting, each engaging different benefits and defects. Prosthetics and optogenetics can be implemented in either mode, but the use of chemical photoswitches is currently limited to downstream

  3. Quantitative evaluation of regional cerebral blood flow by visual stimulation in {sup 99m}Tc- HMPAO brain SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Juh, Ra Hyeong; Suh, Tae Suk; Kwark, Chul Eun; Choe, Bo Young; Lee, Hyoung Koo; Chung, Yong An; Kim, Sung Hoon; Chung, Soo Kyo [College of Medicine, The Catholic Univ. of Seoul, Seoul (Korea, Republic of)

    2002-06-01

    The purpose of this study is to investigate the effects of visual activation and quantitative analysis of regional cerebral blood flow. Visual activation was known to increase regional cerebral blood flow in the visual cortex in occipital lobe. We evaluated that change in the distribution of '9{sup 9m}Tc-HMPAO (Hexamethyl propylene amine oxime) to reflect in regional cerebral blood flow. The six volunteers were injected with 925 MBq (mean ages: 26.75 years, n=6, 3men, 3women) underwent MRI and {sup 99m}Tc-HMPAO SPECT during a rest state with closed eyes and visual stimulated with 8 Hz LED. We delineate the region of interest and calculated the mean count per voxel in each of the fifteen slices to quantitative analysis. The ROI to whole brain ratio and regional index was calculated pixel to pixel subtraction visual non-activation image from visual activation image and constructed brain map using a statistical parameter map(SPM99). The mean regional cerebral blood flow was increased due to visual stimulation. The increase rate of the mean regional cerebral blood flow which of the activation region in primary visual cortex of occipital lobe was 32.50{+-}5.67%. The significant activation sites using a statistical parameter of brain constructed a rendering image and image fusion with SPECT and MRI. Visual activation was revealed significant increase through quantitative analysis in visual cortex. Activation region was certified in Talairach coordinate and primary visual cortex (Ba17),visual association area (Ba18,19) of Brodmann.

  4. Quantitative evaluation of regional cerebral blood flow by visual stimulation in {sup 99m}Tc-HMPAO brain SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Juh, R. H.; Suh, T. S.; Chung, Y. A. [The Catholic Univ., of Korea, Seoul (Korea, Republic of)

    2002-07-01

    The purpose of this study is to investigate the effects of visual activation and quantitative analysis of regional cerebral blood flow. Visual activation was known to increase regional cerebral blood flow in the visual cortex in occipital lobe. We evaluated that change in the distribution of 99mTc-HMPAO (Hexamethyl propylene amine oxime) to reflect in regional cerebral blood flow. The six volunteers were injected with 925 MBq (mean ages: 26.75 years, n=6, 3men, 3women) underwent MRI and 99mTc- HMPAO SPECT during a rest state with closed eyes and visual stimulated with 8 Hz LED. We delineate the region of interest and calculated the mean count per voxel in each of the fifteen slices to quantitative analysis. The ROI to whole brain ratio and regional index was calculated pixel to pixel subtraction visual non-activation image from visual activation image and constructed brain map using a statistical parameter map (SPM99). The mean regional cerebral blood flow was increased due to visual stimulation. The increase rate of the mean regional cerebral blood flow which of the activation region in primary visual cortex of occipital lobe was 32.50{+-}5.67%. The significant activation sites using a statistical parameter of brain constructed a rendering image and image fusion with SPECT and MRI. Visual activation was revealed significant increase through quantitative analysis in visual cortex. Activation region was certified in Talairach coordinate and primary visual cortex (Ba17),visual association area (Ba18,19) of Brodmann.

  5. Cerebral Visual Impairment: Which Perceptive Visual Dysfunctions Can Be Expected in Children with Brain Damage? A Systematic Review

    Science.gov (United States)

    Boot, F. H.; Pel, J. J. M.; van der Steen, J.; Evenhuis, H. M.

    2010-01-01

    The current definition of Cerebral Visual Impairment (CVI) includes all visual dysfunctions caused by damage to, or malfunctioning of, the retrochiasmatic visual pathways in the absence of damage to the anterior visual pathways or any major ocular disease. CVI is diagnosed by exclusion and the existence of many different causes and symptoms make…

  6. Cortical control for prosthetic devices

    Science.gov (United States)

    Schwartz, Andrew B.; Kipke, D. W.; Perepelkin, P. D.

    1996-05-01

    The work presented in this session is part of a project to develop an arm-control system based on neuronal activity recorded from the cerebral cortex. This will make it possible for amputees or paralyzed individuals to move a prosthetic arm or, using functional neural stimulation, their own limbs as effortlessly and with as much skill as intact individuals. We are developing and testing this system in monkeys and hope to have a prototype working in the next couple of years. This project has been made more feasible because we have been able, in the last 15 years to extract, from the brain, a signal that represents arm trajectory accurately. In this paper, we describe how this technique was developed and how we use this as the basis for our control signal. An alternative approach using a self-organizing feature map, an algorithm to deduce arm configuration given an endpoint trajectory and the development of a telemetry system to transmit the neuronal data is described in subsequent papers.

  7. An independent brain-computer interface using covert non-spatial visual selective attention

    Science.gov (United States)

    Zhang, Dan; Maye, Alexander; Gao, Xiaorong; Hong, Bo; Engel, Andreas K.; Gao, Shangkai

    2010-02-01

    In this paper, a novel independent brain-computer interface (BCI) system based on covert non-spatial visual selective attention of two superimposed illusory surfaces is described. Perception of two superimposed surfaces was induced by two sets of dots with different colors rotating in opposite directions. The surfaces flickered at different frequencies and elicited distinguishable steady-state visual evoked potentials (SSVEPs) over parietal and occipital areas of the brain. By selectively attending to one of the two surfaces, the SSVEP amplitude at the corresponding frequency was enhanced. An online BCI system utilizing the attentional modulation of SSVEP was implemented and a 3-day online training program with healthy subjects was carried out. The study was conducted with Chinese subjects at Tsinghua University, and German subjects at University Medical Center Hamburg-Eppendorf (UKE) using identical stimulation software and equivalent technical setup. A general improvement of control accuracy with training was observed in 8 out of 18 subjects. An averaged online classification accuracy of 72.6 ± 16.1% was achieved on the last training day. The system renders SSVEP-based BCI paradigms possible for paralyzed patients with substantial head or ocular motor impairments by employing covert attention shifts instead of changing gaze direction.

  8. Nicotine enhances but does not normalize visual sustained attention and the associated brain network in schizophrenia.

    Science.gov (United States)

    Hong, L Elliot; Schroeder, Matthew; Ross, Thomas J; Buchholz, Brittany; Salmeron, Betty Jo; Wonodi, Ikwunga; Thaker, Gunvant K; Stein, Elliot A

    2011-03-01

    Sustained attention abnormality in schizophrenia is usually refractory to available treatment. Nicotine can transiently improve sustained attention in schizophrenia patients, although its neural mechanisms are unknown. Understanding the neural basis of this effect may lead to new treatment strategies for this cognitive deficit. Twenty schizophrenia patients and 24 healthy comparison smokers participated in a double-blind, placebo-controlled, crossover, randomized functional magnetic resonance imaging study comparing nicotine vs placebo patch on sustained attention, using the rapid visual information-processing task. Schizophrenia patients had impaired visual sustained attention accuracy and processing speed (all P's attention network compared with healthy comparison subjects. Nicotine administration enhanced accuracy and processing speed compared with placebo (all P's ≤.006), with no drug × diagnosis interactions. However, schizophrenia patients' task performance remained impaired during the nicotine condition, even when compared with healthy comparison subjects in the placebo condition (all P's ≤.01). Nicotine exerted no significant reversal of the impaired attention network associated with schizophrenia. Activations in brain regions associated with nicotine-induced behavioral improvement were not significantly different between patients and comparison subjects. Thus, nicotine transiently enhanced sustained attention similarly in schizophrenia patients and in healthy comparison smokers. The neural mechanisms for this nicotinic effect in schizophrenia appear similar to those for healthy comparison subjects. However, nicotine, at least in a single sustained dose, does not normalize impaired sustained attention and its associated brain network in schizophrenia. These findings provide guidance for developing new treatment strategies for the sustained attention deficit in schizophrenia.

  9. Subjective visual perception: from local processing to emergent phenomena of brain activity.

    Science.gov (United States)

    Panagiotaropoulos, Theofanis I; Kapoor, Vishal; Logothetis, Nikos K

    2014-05-05

    The combination of electrophysiological recordings with ambiguous visual stimulation made possible the detection of neurons that represent the content of subjective visual perception and perceptual suppression in multiple cortical and subcortical brain regions. These neuronal populations, commonly referred to as the neural correlates of consciousness, are more likely to be found in the temporal and prefrontal cortices as well as the pulvinar, indicating that the content of perceptual awareness is represented with higher fidelity in higher-order association areas of the cortical and thalamic hierarchy, reflecting the outcome of competitive interactions between conflicting sensory information resolved in earlier stages. However, despite the significant insights into conscious perception gained through monitoring the activities of single neurons and small, local populations, the immense functional complexity of the brain arising from correlations in the activity of its constituent parts suggests that local, microscopic activity could only partially reveal the mechanisms involved in perceptual awareness. Rather, the dynamics of functional connectivity patterns on a mesoscopic and macroscopic level could be critical for conscious perception. Understanding these emergent spatio-temporal patterns could be informative not only for the stability of subjective perception but also for spontaneous perceptual transitions suggested to depend either on the dynamics of antagonistic ensembles or on global intrinsic activity fluctuations that may act upon explicit neural representations of sensory stimuli and induce perceptual reorganization. Here, we review the most recent results from local activity recordings and discuss the potential role of effective, correlated interactions during perceptual awareness.

  10. Hemispheric asymmetry of visual scene processing in the human brain: evidence from repetition priming and intrinsic activity.

    Science.gov (United States)

    Stevens, W Dale; Kahn, Itamar; Wig, Gagan S; Schacter, Daniel L

    2012-08-01

    Asymmetrical specialization of cognitive processes across the cerebral hemispheres is a hallmark of healthy brain development and an important evolutionary trait underlying higher cognition in humans. While previous research, including studies of priming, divided visual field presentation, and split-brain patients, demonstrates a general pattern of right/left asymmetry of form-specific versus form-abstract visual processing, little is known about brain organization underlying this dissociation. Here, using repetition priming of complex visual scenes and high-resolution functional magnetic resonance imaging (MRI), we demonstrate asymmetrical form specificity of visual processing between the right and left hemispheres within a region known to be critical for processing of visual spatial scenes (parahippocampal place area [PPA]). Next, we use resting-state functional connectivity MRI analyses to demonstrate that this functional asymmetry is associated with differential intrinsic activity correlations of the right versus left PPA with regions critically involved in perceptual versus conceptual processing, respectively. Our results demonstrate that the PPA comprises lateralized subregions across the cerebral hemispheres that are engaged in functionally dissociable yet complementary components of visual scene analysis. Furthermore, this functional asymmetry is associated with differential intrinsic functional connectivity of the PPA with distinct brain areas known to mediate dissociable cognitive processes.

  11. VERP and brain imaging for identifying levels of visual dorsal and ventral stream function in typical and preterm infants.

    Science.gov (United States)

    Braddick, Oliver; Atkinson, Janette; Wattam-Bell, John

    2011-01-01

    Visual development is a key area for understanding and assessing early brain development. Different levels in the hierarchy of visual processing, from the initial response to flashes of light, through selective responses to contour orientation and motion in primary visual cortex (V1), to global processing in extrastriate of large-scale patterns of form and motion, can each be assessed using stimuli designed to isolate specific neural activity in visual event-related potentials (VERPs). This approach has been used to reveal the sequence of emergence of different visual cortical functions in the first 6 months of typical human development, and to provide early indicators of anomalies in brain development. Delayed or absent onset of orientation-reversal (OR-)VERPs, as a measure of cortical development, has been shown to be a sensitive indicator of perinatal brain damage in both term-born and prematurely born infants. Direction-reversal (DR-)VERPs appear a few weeks later than OR-VERPs in typical development, and are further delayed in even healthy children born preterm, reflecting possible early vulnerability of the motion (dorsal stream) system. High-density recordings of responses to global motion and global form patterns show that these extrastriate systems are typically functional by 5 months of age, but the topography of the activity distributions shows that the brain systems underlying these responses are radically reorganized between infancy and adulthood. In prematurely born infants whose structural brain MRI was evaluated at birth, the onset of the response is absent or delayed in those with severe brain injury, while in those with mild/moderate brain injury the response is present but its spatial organization is further from the adult pattern than those in controls. These findings are related to the development of distinct networks of brain areas in the dorsal and ventral cortical streams, and the apparent vulnerability of the dorsal-stream network in a wide

  12. Neural-Network Control Of Prosthetic And Robotic Hands

    Science.gov (United States)

    Buckley, Theresa M.

    1991-01-01

    Electronic neural networks proposed for use in controlling robotic and prosthetic hands and exoskeletal or glovelike electromechanical devices aiding intact but nonfunctional hands. Specific to patient, who activates grasping motion by voice command, by mechanical switch, or by myoelectric impulse. Patient retains higher-level control, while lower-level control provided by neural network analogous to that of miniature brain. During training, patient teaches miniature brain to perform specialized, anthropomorphic movements unique to himself or herself.

  13. Steady state visually evoked potentials based Brain computer interface test outside the lab

    Directory of Open Access Journals (Sweden)

    Eduardo Francisco Caicedo Bravo

    2016-06-01

    Full Text Available Context: Steady State Visually Evoked Potentials (SSVEP are brain signals which are one of the most promising signals for Brain Computer Interfaces (BCIs implementation, however, SSVEP based BCI generally are proven in a controlled environment and there are a few tests in demanding conditions.Method: We present a SSVEP based BCI system that was used outside the lab in a noisy environment with distractions, and with the presence of public. For the tests, we showed a maze in a laptop where the user could move an avatar looking for a target that is represented by a house.  In order to move the avatar, the volunteer must stare at one of the four visual stimuli; the four visual stimuli represent the four directions: right, up, left, and down. The system is proven without any calibration procedure.Results: 32 volunteers utilized the system and 20 achieved the target with an accuracy above 60%, including 9 with an accuracy of 100%, 7 achieved the target with an accuracy below 60% and 5 left without achieving the goal. For the volunteers who reached accuracy above 60%, the results of the performance achieved an average of 6,4s for command detections, precision of 79% and information transfer rate (ITR of 8,78 bits/s.Conclusions: We showed a SSVEP based BCI system with low cost, it was proved in a public event, it did not have calibration procedures, it was easy to install, and it was used for people in a wide age range. The results show that it is possible to bring this kind of systems to environments outside the laboratory.

  14. Stimulus Specificity of Brain-Computer Interfaces Based on Code Modulation Visual Evoked Potentials.

    Directory of Open Access Journals (Sweden)

    Qingguo Wei

    Full Text Available A brain-computer interface (BCI based on code modulated visual evoked potentials (c-VEP is among the fastest BCIs that have ever been reported, but it has not yet been given a thorough study. In this study, a pseudorandom binary M sequence and its time lag sequences are utilized for modulation of different stimuli and template matching is adopted as the method for target recognition. Five experiments were devised to investigate the effect of stimulus specificity on target recognition and we made an effort to find the optimal stimulus parameters for size, color and proximity of the stimuli, length of modulation sequence and its lag between two adjacent stimuli. By changing the values of these parameters and measuring classification accuracy of the c-VEP BCI, an optimal value of each parameter can be attained. Experimental results of ten subjects showed that stimulus size of visual angle 3.8°, white, spatial proximity of visual angle 4.8° center to center apart, modulation sequence of length 63 bits and the lag of 4 bits between adjacent stimuli yield individually superior performance. These findings provide a basis for determining stimulus presentation of a high-performance c-VEP based BCI system.

  15. Reactivity of dogs' brain oscillations to visual stimuli measured with non-invasive electroencephalography.

    Directory of Open Access Journals (Sweden)

    Miiamaaria V Kujala

    Full Text Available Studying cognition of domestic dogs has gone through a renaissance within the last decades. However, although the behavioral studies of dogs are beginning to be common in the field of animal cognition, the neural events underlying cognition remain unknown. Here, we employed a non-invasive electroencephalography, with adhesive electrodes attached to the top of the skin, to measure brain activity of from 8 domestic dogs (Canis familiaris while they stayed still to observe photos of dog and human faces. Spontaneous oscillatory activity of the dogs, peaking in the sensors over the parieto-occipital cortex, was suppressed statistically significantly during visual task compared with resting activity at the frequency of 15-30 Hz. Moreover, a stimulus-induced low-frequency (~2-6 Hz suppression locked to the stimulus onset was evident at the frontal sensors, possibly reflecting a motor rhythm guiding the exploratory eye movements. The results suggest task-related reactivity of the macroscopic oscillatory activity in the dog brain. To our knowledge, the study is the first to reveal non-invasively measured reactivity of brain electrophysiological oscillations in healthy dogs, and it has been based purely on positive operant conditional training, without the need for movement restriction or medication.

  16. Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration

    Science.gov (United States)

    Lorach, Henri; Lei, Xin; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Dalal, Roopa; Huie, Philip; Harris, James; Palanker, Daniel

    2015-01-01

    Purpose Prosthetic restoration of partial sensory loss leads to interactions between artificial and natural inputs. Ideally, the rehabilitation should allow perceptual fusion of the two modalities. Here we studied the interactions between normal and prosthetic vision in a rodent model of local retinal degeneration. Methods Implantation of a photovoltaic array in the subretinal space of normally sighted rats induced local degeneration of the photoreceptors above the chip, and the inner retinal neurons in this area were electrically stimulated by the photovoltaic implant powered by near-infrared (NIR) light. We studied prosthetic and natural visually evoked potentials (VEP) in response to simultaneous stimulation by NIR and visible light patterns. Results We demonstrate that electrical and natural VEPs summed linearly in the visual cortex, and both responses decreased under brighter ambient light. Responses to visible light flashes increased over 3 orders of magnitude of contrast (flash/background), while for electrical stimulation the contrast range was limited to 1 order of magnitude. The maximum amplitude of the prosthetic VEP was three times lower than the maximum response to a visible flash over the same area on the retina. Conclusions Ambient light affects prosthetic responses, albeit much less than responses to visible stimuli. Prosthetic representation of contrast in the visual scene can be encoded, to a limited extent, by the appropriately calibrated stimulus intensity, which also depends on the ambient light conditions. Such calibration will be important for patients combining central prosthetic vision with natural peripheral sight, such as in age-related macular degeneration. PMID:26618643

  17. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia.

    Directory of Open Access Journals (Sweden)

    Carolyn D Langen

    Full Text Available Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1 middle-aged versus elderly subjects; and (2 patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only

  18. Anticoagulation for Prosthetic Valves

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kaneko

    2013-01-01

    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  19. The effect of visual training for patients with visual field defects due to brain damage : a systematic review

    NARCIS (Netherlands)

    Bouwmeester, Lies; Heutink, Joost; Lucas, Cees

    2007-01-01

    The objective of this review was to evaluate whether systematic visual training leads to ( 1) a restitution of the visual field ( restoration), ( 2) an increase in the visual search field size or an improvement in scanning strategies (compensation) and ( 3) a transfer of training-related improvement

  20. Steady State Visual Evoked Potential Based Brain-Computer Interface for Cognitive Assessment

    DEFF Research Database (Denmark)

    Westergren, Nicolai; Bendtsen, Rasmus L.; Kjær, Troels W.;

    2016-01-01

    decline is important. Cognitive decline may be detected using fullyautomated computerized assessment. Such systems will provide inexpensive and widely available screenings of cognitive ability. The aim of this pilot study is to develop a real time steady state visual evoked potential (SSVEP) based brain-computer...... subjects achieved an information transfer rate (ITR) of 14:64 bits/min ± 7:63 bits=min and a subject test performance of 47:22% ± 34:10%. This study suggests that BCI may be applicable in practice as a computerized cognitive assessment tool. However, many improvements are required for the system...... interface (BCI) for neurological cognitive assessment. It is intended for use by patients who suffer from diseases impairing their motor skills, but are still able to control their gaze. Results are based on 11 healthy test subjects. The system performance have an average accuracy of 100% ± 0%. The test...

  1. Prosthetic stomatitis with removable dentures

    Directory of Open Access Journals (Sweden)

    Rozalieva Yu.Yu.

    2012-06-01

    Full Text Available The Research Objective: To study patients with prosthetic stomatitis, who use the removable laminar dentures. Materials: The consultations and treatment of 79 patients aged 47-65 years have been conducted. The patients have been divided into two clinical groups. The first clinical group (39 persons with the performance of immediate prosthet-ics; the second control clinical group (40 persons — the permanent dentures were produced without the preliminary instruction. Results: All the patients, having the laminar dentures without the preliminary use of immediate constructions of dentures, in spite of repeated correction of them, have had changes of dentures and transitory fold. Patients have been exposed to prosthetic stomatitis of different etiology (without trauma; the single-shot or multiple correction of dentures by the method of rebasing with using of cold cure plastics has been made. Conclusion: Structural and functional changes of dentition during the prosthetic stomatitis lead to disorders, associated by the mucositis. Use of the term of «prosthetic stomatitis» reflects etiological and pathogenetic component of changes in the denture-supporting tissues

  2. How does Arabic orthographic connectivity modulate brain activity during visual word recognition: an ERP study.

    Science.gov (United States)

    Taha, Haitham; Ibrahim, Raphiq; Khateb, Asaid

    2013-04-01

    One of the unique features of the Arabic orthography that differentiates it from many other alphabetical ones is the fact that most letters connect obligatorily to each other. Hence, these letters change their forms according to the location in the word (i.e. beginning, middle, or end), leading to the suggestion that connectivity adds a visual load which negatively impacts reading in Arabic. In this study, we investigated the effects of the orthographic connectivity on the time course of early brain electric responses during the visual word recognition. For this purpose, we collected event-related potentials (ERPs) from adult skilled readers while performing a lexical decision task using fully connected (Cw), partially connected and non-connected words (NCw). Reaction times variance was higher and accuracy was lower in NCw compared to Cw words. ERPs analysis revealed significant amplitude and latency differences between Cw and NCw at posterior electrodes during the N170 component which implied the temporo-occipital areas. Our findings show that instead of slowing down reading, orthographic connectivity in Arabic skilled readers seems to impact positively the reading process already during the early stages of word recognition. These results are discussed in relation to previous observations in the literature.

  3. Prediction of auditory and visual p300 brain-computer interface aptitude.

    Directory of Open Access Journals (Sweden)

    Sebastian Halder

    Full Text Available OBJECTIVE: Brain-computer interfaces (BCIs provide a non-muscular communication channel for patients with late-stage motoneuron disease (e.g., amyotrophic lateral sclerosis (ALS or otherwise motor impaired people and are also used for motor rehabilitation in chronic stroke. Differences in the ability to use a BCI vary from person to person and from session to session. A reliable predictor of aptitude would allow for the selection of suitable BCI paradigms. For this reason, we investigated whether P300 BCI aptitude could be predicted from a short experiment with a standard auditory oddball. METHODS: Forty healthy participants performed an electroencephalography (EEG based visual and auditory P300-BCI spelling task in a single session. In addition, prior to each session an auditory oddball was presented. Features extracted from the auditory oddball were analyzed with respect to predictive power for BCI aptitude. RESULTS: Correlation between auditory oddball response and P300 BCI accuracy revealed a strong relationship between accuracy and N2 amplitude and the amplitude of a late ERP component between 400 and 600 ms. Interestingly, the P3 amplitude of the auditory oddball response was not correlated with accuracy. CONCLUSIONS: Event-related potentials recorded during a standard auditory oddball session moderately predict aptitude in an audiory and highly in a visual P300 BCI. The predictor will allow for faster paradigm selection. SIGNIFICANCE: Our method will reduce strain on patients because unsuccessful training may be avoided, provided the results can be generalized to the patient population.

  4. Visual Scanning in the Recognition of Facial Affect in Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Suzane Vassallo

    2011-05-01

    Full Text Available We investigated the visual scanning strategy employed by a group of individuals with a severe traumatic brain injury (TBI during a facial affect recognition task. Four males with a severe TBI were matched for age and gender with 4 healthy controls. Eye movements were recorded while pictures of static emotional faces were viewed (i.e., sad, happy, angry, disgusted, anxious, surprised. Groups were compared with respect to accuracy in labelling the emotional facial expression, reaction time, number and duration of fixations to internal (i.e., eyes + nose + mouth, and external (i.e., all remaining regions of the stimulus. TBI participants demonstrated significantly reduced accuracy and increased latency in facial affect recognition. Further, they demonstrated no significant difference in the number or duration of fixations to internal versus external facial regions. Control participants, however, fixated more frequently and for longer periods of time upon internal facial features. Impaired visual scanning can contribute to inaccurate interpretation of facial expression and this can disrupt interpersonal communication. The scanning strategy demonstrated by our TBI group appears more ‘widespread’ than that employed by their normal counterparts. Further work is required to elucidate the nature of the scanning strategy used and its potential variance in TBI.

  5. GPU-accelerated brain connectivity reconstruction and visualization in large-scale electron micrographs

    KAUST Repository

    Jeong, Wonki

    2011-01-01

    This chapter introduces a GPU-accelerated interactive, semiautomatic axon segmentation and visualization system. Two challenging problems have been addressed: the interactive 3D axon segmentation and the interactive 3D image filtering and rendering of implicit surfaces. The reconstruction of neural connections to understand the function of the brain is an emerging and active research area in neuroscience. With the advent of high-resolution scanning technologies, such as 3D light microscopy and electron microscopy (EM), reconstruction of complex 3D neural circuits from large volumes of neural tissues has become feasible. Among them, only EM data can provide sufficient resolution to identify synapses and to resolve extremely narrow neural processes. These high-resolution, large-scale datasets pose challenging problems, for example, how to process and manipulate large datasets to extract scientifically meaningful information using a compact representation in a reasonable processing time. The running time of the multiphase level set segmentation method has been measured on the CPU and GPU. The CPU version is implemented using the ITK image class and the ITK distance transform filter. The numerical part of the CPU implementation is similar to the GPU implementation for fair comparison. The main focus of this chapter is introducing the GPU algorithms and their implementation details, which are the core components of the interactive segmentation and visualization system. © 2011 Copyright © 2011 NVIDIA Corporation and Wen-mei W. Hwu Published by Elsevier Inc. All rights reserved..

  6. The role of different cues in the brain mechanism on visual spatial attention

    Institute of Scientific and Technical Information of China (English)

    SONG Weiqun; LUO Yuejia; CHI Song; JI Xunming; LING Feng; ZHAO Lun; WANG Maobin; SHI Jiannong

    2006-01-01

    The visual spatial attention mechanism in the brain was studied in 16 young subjects through the visual search paradigm of precue-target by the event-related potential (ERP) technique, with the attentive ranges cued by different scales of Chinese character and region cues. The results showed that the response time for Chinese character cues was much longer than that for region cues especially for small region cues. With the exterior interferences, the target stimuli recognition under region cues was much quicker than that under Chinese character cues. Compared with that under region cues, targets under Chinese character cues could lead to increase of the posterior P1,decrease of the N1 and increase of the P2. It should also be noted that the differences between region cues and Chinese character cues were affected by the interference types. Under exterior interferences, no significant difference was found between region cues and Chinese character cues; however, it was not the case under the interior interferences. Considering the difference between the exterior interferences and the interior interferences, we could conclude that with the increase of difficulty in target recognition there was obvious difference in the consumption of anterior frontal resources by target stimuli under the two kinds of cues.

  7. Genetic effects on source level evoked and induced oscillatory brain responses in a visual oddball task.

    Science.gov (United States)

    Antonakakis, Marios; Zervakis, Michalis; van Beijsterveldt, Catharina E M; Boomsma, Dorret I; De Geus, Eco J C; Micheloyannis, Sifis; Smit, Dirk J A

    2016-02-01

    Stimuli in simple oddball target detection paradigms cause evoked responses in brain potential. These responses are heritable traits, and potential endophenotypes for clinical phenotypes. These stimuli also cause responses in oscillatory activity, both evoked responses phase-locked to stimulus presentation and phase-independent induced responses. Here, we investigate whether phase-locked and phase-independent oscillatory responses are heritable traits. Oscillatory responses were examined in EEG recordings from 213 twin pairs (91 monozygotic and 122 dizygotic twins) performing a visual oddball task. After group Independent Component Analysis (group-ICA) and time-frequency decomposition, individual differences in evoked and induced oscillatory responses were compared between MZ and DZ twin pairs. Induced (phase-independent) oscillatory responses consistently showed the highest heritability (24-55%) compared to evoked (phase-locked) oscillatory responses and spectral energy, which revealed lower heritability at 1-35.6% and 4.5-32.3%, respectively. Since the phase-independent induced response encodes functional aspects of the brain response to target stimuli different from evoked responses, we conclude that the modulation of ongoing oscillatory activity may serve as an additional endophenotype for behavioral phenotypes and psychiatric genetics.

  8. Brains of verbal memory specialists show anatomical differences in language, memory and visual systems.

    Science.gov (United States)

    Hartzell, James F; Davis, Ben; Melcher, David; Miceli, Gabriele; Jovicich, Jorge; Nath, Tanmay; Singh, Nandini Chatterjee; Hasson, Uri

    2016-05-01

    We studied a group of verbal memory specialists to determine whether intensive oral text memory is associated with structural features of hippocampal and lateral-temporal regions implicated in language processing. Professional Vedic Sanskrit Pandits in India train from childhood for around 10years in an ancient, formalized tradition of oral Sanskrit text memorization and recitation, mastering the exact pronunciation and invariant content of multiple 40,000-100,000 word oral texts. We conducted structural analysis of gray matter density, cortical thickness, local gyrification, and white matter structure, relative to matched controls. We found massive gray matter density and cortical thickness increases in Pandit brains in language, memory and visual systems, including i) bilateral lateral temporal cortices and ii) the anterior cingulate cortex and the hippocampus, regions associated with long and short-term memory. Differences in hippocampal morphometry matched those previously documented for expert spatial navigators and individuals with good verbal working memory. The findings provide unique insight into the brain organization implementing formalized oral knowledge systems.

  9. Exploring combinations of auditory and visual stimuli for gaze-independent brain-computer interfaces.

    Directory of Open Access Journals (Sweden)

    Xingwei An

    Full Text Available For Brain-Computer Interface (BCI systems that are designed for users with severe impairments of the oculomotor system, an appropriate mode of presenting stimuli to the user is crucial. To investigate whether multi-sensory integration can be exploited in the gaze-independent event-related potentials (ERP speller and to enhance BCI performance, we designed a visual-auditory speller. We investigate the possibility to enhance stimulus presentation by combining visual and auditory stimuli within gaze-independent spellers. In this study with N = 15 healthy users, two different ways of combining the two sensory modalities are proposed: simultaneous redundant streams (Combined-Speller and interleaved independent streams (Parallel-Speller. Unimodal stimuli were applied as control conditions. The workload, ERP components, classification accuracy and resulting spelling speed were analyzed for each condition. The Combined-speller showed a lower workload than uni-modal paradigms, without the sacrifice of spelling performance. Besides, shorter latencies, lower amplitudes, as well as a shift of the temporal and spatial distribution of discriminative information were observed for Combined-speller. These results are important and are inspirations for future studies to search the reason for these differences. For the more innovative and demanding Parallel-Speller, where the auditory and visual domains are independent from each other, a proof of concept was obtained: fifteen users could spell online with a mean accuracy of 87.7% (chance level <3% showing a competitive average speed of 1.65 symbols per minute. The fact that it requires only one selection period per symbol makes it a good candidate for a fast communication channel. It brings a new insight into the true multisensory stimuli paradigms. Novel approaches for combining two sensory modalities were designed here, which are valuable for the development of ERP-based BCI paradigms.

  10. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem.

    Science.gov (United States)

    McClay, Wilbert A; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T; Nagarajan, Srikantan S

    2015-09-30

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user's intent for specific keyboard strikes or mouse button presses. The BCI's data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject's MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse.

  11. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem

    Directory of Open Access Journals (Sweden)

    Wilbert A. McClay

    2015-09-01

    Full Text Available Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse.

  12. Contralateral Cortical Organisation of Information in Visual Short-Term Memory: Evidence from Lateralized Brain Activity during Retrieval

    Science.gov (United States)

    Fortier-Gauthier, Ulysse; Moffat, Nicolas; Dell'Acqua, Robert; McDonald, John J.; Jolicoeur, Pierre

    2012-01-01

    We studied brain activity during retention and retrieval phases of two visual short-term memory (VSTM) experiments. Experiment 1 used a balanced memory array, with one color stimulus in each hemifield, followed by a retention interval and a central probe, at the fixation point that designated the target stimulus in memory about which to make a…

  13. The effect of repetition of infrequent familiar and unfamiliar visual patterns on components of the event-related brain potential.

    NARCIS (Netherlands)

    A. Kok; H. de Looren de Jong

    1980-01-01

    Examined changes in the waveforms of the event-related brain potential (ERP) during repeated presentations of infrequent-familiar and infrequent-unfamiliar visual patterns; Ss were 12 male university students. The EEG waveforms were averaged separately for each presentation of the 2 types of stimuli

  14. Visual and SPM Analysis of Brain Perfusion SPECT in Patients of Dementia with Lewy Bodies with Clinical Correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Young; Park, Kyung Won; Kim, Jae Woo [College of Medicine, Univ. of Donga, Busan (Korea, Republic of)

    2003-07-01

    Dementia with Lewy bodies (DLB) is widely recognized as the second commonest form of degenerative dementia. Its core clinical features include persistent visual hallucinosis, fluctuating cognitive impairment and parkinsonism. We evaluated the brain perfusion of dementia with Lewy bodies by SPM analysis and correlated the findings with clinical symptom. Twelve DLB patients (mean age ; 68.88.3 yrs, K-MMSE ; 17.36) and 30 control subjects (mean age ; 60.17.7 yrs) were included. Control subjects were selected by 28 items of exclusion criteria and checked by brain CT or MRI except 3 subjects. Tc-99m HMPAO brain perfusion SPECT was performed and the image data were analyzed by visual interpretation and SPM99 as routine protocol. In visual analysis, 7 patients showed hypoperfusion in both frontal, temporal, parietal and occipital lobe, 2 patients in both frontal, temporal and parietal lobe, 2 patients in both temporal, parietal and occipital lobe, 1 patients in left temporal, parietal and occipital lobe. In SPM analysis (uncorrected p<0.01), significant hypoperfusion was shown in Lt inf. frontal gyrus (B no.47), both inf. parietal lobule (Rt B no.40), Rt parietal lobe (precuneus), both sup. temporal gyrus (Rt B no.42), Rt mid temporal gyrus, Lt transverse temporal gyrus (B no.41), both para hippocampal gyrus, Rt thalamus (pulvinar), both cingulate gyrus (Lt B no.24, Lt B no.25, Rt B no.23, Rt B no.24, Rt B no.33), Rt caudate body, both occipital lobe (cuneus, Lt B no.17, Rt B no.18). All patients had fluctuating cognition and parkinsonism, and 9 patients had visual hallucination. The result of SPM analysis was well correlated with visual interpretation and may be helpful to specify location to correlate with clinical symptom. Significant perfusion deficits in occipital region including visual cortex and visual association area are characteristic findings in DLB. Abnormalities in these areas may be important in understanding symptoms of visual hallucination and

  15. [Prosthetic dental alloys. 1].

    Science.gov (United States)

    Quintero Engelmbright, M A

    1990-11-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements.

  16. [Prosthetic dental alloys (2)].

    Science.gov (United States)

    Quintero Englembright, M A

    1990-12-01

    A wide variety of restoration materials for prosthetic odontology is now available to the dental surgeon, either of the covalent type (acrylic resins), metallic (alloys), ionic (porcelains), or a combination of them, as in the so-called composites, such as the composite resins, or as ceramics-metals mixtures. An example of the latter is a product called Miracle-Mix, a glass ionomere cement reinforced with an amalgam alloy. In those cases where the blend is done by a synterization process, the material is called Cermet. The above-listed alternatives clearly evidence day-to-day advances in odontology, with researchers and manufacturers engaged the world over in improving existing products or developing new ones to enrich the dentist's armamentarium. As a side effect of this constant renewal, those dentists who have failed to update their knowledge fall behind in their practice as they persist in using products they have known for years, and may be deceived by advertisements of too-often unreliable products. It is, therefore, important to be aware of available products and their latest improvements.

  17. Amputations and prosthetics.

    Science.gov (United States)

    Pinzur, M S

    1999-01-01

    The author presents in a condensed way an overview of the principles of limb amputations and further treatment of patients who underwent such a procedure. The metabolic cost of walking, load transfer, and wound healing are reviewed in a concise manner. Particular attention is given to blood supply to the wound and methods to determine adequate perfusion with a clear analysis of the pro and cons of the Doppler method. Pediatric amputations, because of their specificity, are considered apart. Disarticulation of limbs is the method of choice in children, because of it retains growth potential of the bone and prevents bony overgrowth of the stump. The article discusses the main indications for limb amputations: trauma, peripheral vascular disease, musculoskeletal tumors and gas gangrene. In every case the specificity of the amputation is considered by the author. Postoperative care is also presented, with a short description of possible complications. Pain is the most common and treatment strategies should be similar to those used in treating patients with major reflex sympathetic causalgia. Edema, joint contracture, wound failure and dermatologic problems are all shortly reviewed. The last part of the article treats with the principles of prosthetics in both the upper and lower limb. These principles are presented basing on the level of amputation: for the upper limb hand, transradial, transhumeral amputations and shoulder disarticulation. For the lower limb foot and ankle, transtibial and transfemoral amputations are considered.

  18. Prosthetic helping hand

    Science.gov (United States)

    Vest, Thomas W. (Inventor); Carden, James R. (Inventor); Norton, William E. (Inventor); Belcher, Jewell G. (Inventor)

    1992-01-01

    A prosthetic device for below-the-elbow amputees, having a C-shaped clamping mechanism for grasping cylindrical objects, is described. The clamping mechanism is pivotally mounted to a cuff that fits on the amputee's lower arm. The present invention is utilized by placing an arm that has been amputated below the elbow into the cuff. The clamping mechanism then serves as a hand whenever it becomes necessary for the amputee to grasp a cylindrical object such as a handle, a bar, a rod, etc. To grasp the cylindrical object, the object is jammed against the opening in the C-shaped spring, causing the spring to open, the object to pass to the center of the spring, and the spring to snap shut behind the object. Various sizes of clamping mechanisms can be provided and easily interchanged to accommodate a variety of diameters. With the extension that pivots and rotates, the clamping mechanism can be used in a variety of orientations. Thus, this invention provides the amputee with a clamping mechanism that can be used to perform a number of tasks.

  19. Windows into the Visual Brain: New Discoveries about the Visual System, Its Functions, and Implications for Practitioners

    Science.gov (United States)

    Jan, James E.; Heaven, Roberta K. B.; Matsuba, Carey; Langley, M. Beth; Roman-Lantzy, Christine; Anthony, Tanni L

    2013-01-01

    Introduction: In recent years, major progress has been made in understanding the human visual system because of new investigative techniques. These developments often contradict older concepts about visual function. Methods: A detailed literature search and interprofessional discussions. Results: Recent innovative neurological tests are described…

  20. fMRI mapping of the visual system in the mouse brain with interleaved snapshot GE-EPI.

    Science.gov (United States)

    Niranjan, Arun; Christie, Isabel N; Solomon, Samuel G; Wells, Jack A; Lythgoe, Mark F

    2016-06-10

    The use of functional magnetic resonance imaging (fMRI) in mice is increasingly prevalent, providing a means to non-invasively characterise functional abnormalities associated with genetic models of human diseases. The predominant stimulus used in task-based fMRI in the mouse is electrical stimulation of the paw. Task-based fMRI in mice using visual stimuli remains underexplored, despite visual stimuli being common in human fMRI studies. In this study, we map the mouse brain visual system with BOLD measurements at 9.4T using flashing light stimuli with medetomidine anaesthesia. BOLD responses were observed in the lateral geniculate nucleus, the superior colliculus and the primary visual area of the cortex, and were modulated by the flashing frequency, diffuse vs focussed light and stimulus context. Negative BOLD responses were measured in the visual cortex at 10Hz flashing frequency; but turned positive below 5Hz. In addition, the use of interleaved snapshot GE-EPI improved fMRI image quality without diminishing the temporal contrast-noise-ratio. Taken together, this work demonstrates a novel methodological protocol in which the mouse brain visual system can be non-invasively investigated using BOLD fMRI.

  1. Complex network inference from P300 signals: Decoding brain state under visual stimulus for able-bodied and disabled subjects

    Science.gov (United States)

    Gao, Zhong-Ke; Cai, Qing; Dong, Na; Zhang, Shan-Shan; Bo, Yun; Zhang, Jie

    2016-10-01

    Distinguishing brain cognitive behavior underlying disabled and able-bodied subjects constitutes a challenging problem of significant importance. Complex network has established itself as a powerful tool for exploring functional brain networks, which sheds light on the inner workings of the human brain. Most existing works in constructing brain network focus on phase-synchronization measures between regional neural activities. In contrast, we propose a novel approach for inferring functional networks from P300 event-related potentials by integrating time and frequency domain information extracted from each channel signal, which we show to be efficient in subsequent pattern recognition. In particular, we construct brain network by regarding each channel signal as a node and determining the edges in terms of correlation of the extracted feature vectors. A six-choice P300 paradigm with six different images is used in testing our new approach, involving one able-bodied subject and three disabled subjects suffering from multiple sclerosis, cerebral palsy, traumatic brain and spinal-cord injury, respectively. We then exploit global efficiency, local efficiency and small-world indices from the derived brain networks to assess the network topological structure associated with different target images. The findings suggest that our method allows identifying brain cognitive behaviors related to visual stimulus between able-bodied and disabled subjects.

  2. Prosthetic valve endocarditis 1976-1987. Antibiotics, anticoagulation, and stroke.

    Science.gov (United States)

    Davenport, J; Hart, R G

    1990-07-01

    We retrospectively reviewed the clinical characteristics and outcomes of 61 patients with 62 episodes of prosthetic valve endocarditis, paying particular attention to neurologic complications (stroke). Atypical features of the group included a benign outcome of early postoperative infection (18% mortality) and a high stroke morbidity and mortality rate with Staphylococcus epidermidis infections. Eleven patients (18%) suffered an embolic stroke, most less than or equal to 3 days after diagnosis and before the initiation of antimicrobial therapy; the rate of embolic stroke recurrence was low (9%). The risk of embolic stroke was lower with bioprosthetic than with mechanical valves. No protective effect of anticoagulation therapy with warfarin was observed. Six patients (8%) suffered brain hemorrhage due to septic arteritis, brain infarction, or undetermined causes; no specific risk of hemorrhagic stroke was evident with anticoagulation therapy. Antibiotic treatment appears to be more important than anticoagulation to prevent neurologic complications in patients with prosthetic valve endocarditis.

  3. Visual processing of multiple elements in the dyslexic brain: evidence for a superior parietal dysfunction

    Directory of Open Access Journals (Sweden)

    Muriel Anne Lobier

    2014-07-01

    Full Text Available The visual attention (VA span deficit hypothesis of developmental dyslexia posits that impaired multiple element processing can be responsible for poor reading outcomes. In VA span impaired dyslexic children, poor performance on letter report tasks is associated with reduced parietal activations for multiple letter processing. While this hints towards a non-specific, attention-based dysfunction, it is still unclear whether reduced parietal activity generalizes to other types of stimuli. Furthermore, putative links between reduced parietal activity and reduced ventral occipito-temporal (vOT in dyslexia have yet to be explored. Using fMRI, we measured brain activity in 12 VA span impaired dyslexic adults and 12 adult skilled readers while they carried out a categorization task on single or multiple alphanumeric or non-alphanumeric characters. While healthy readers activated parietal areas more strongly for multiple than single element processing (right-sided for alphanumeric and bilateral for non-alphanumeric, similar stronger multiple element right parietal activations were absent for dyslexic participants. Contrasts between skilled and dyslexic readers revealed significantly reduced right superior parietal lobule (SPL activity for dyslexic readers regardless of stimuli type. Using a priori anatomically defined ROI, we showed that neural activity was reduced for dyslexic participants in both SPL and vOT bilaterally. Finally, we used multiple regressions to test whether SPL activity could predict vOT activity in each group. In the left hemisphere, SPL activity modulated vOT activity for both normal and dyslexic readers. In contrast, in the right hemisphere, SPL activity modulated vOT activity only for dyslexic readers. These results bring critical support to the visual attention interpretation of the VA Span deficit. In addition, they offer a new insight on how deficits in automatic vOT based word recognition could arise in developmental dyslexia.

  4. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem

    Science.gov (United States)

    McClay, Wilbert A.; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T.; Nagarajan, Srikantan S.

    2015-01-01

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432

  5. Resolving the neural dynamics of visual and auditory scene processing in the human brain: a methodological approach

    Science.gov (United States)

    Teng, Santani

    2017-01-01

    In natural environments, visual and auditory stimulation elicit responses across a large set of brain regions in a fraction of a second, yielding representations of the multimodal scene and its properties. The rapid and complex neural dynamics underlying visual and auditory information processing pose major challenges to human cognitive neuroscience. Brain signals measured non-invasively are inherently noisy, the format of neural representations is unknown, and transformations between representations are complex and often nonlinear. Further, no single non-invasive brain measurement technique provides a spatio-temporally integrated view. In this opinion piece, we argue that progress can be made by a concerted effort based on three pillars of recent methodological development: (i) sensitive analysis techniques such as decoding and cross-classification, (ii) complex computational modelling using models such as deep neural networks, and (iii) integration across imaging methods (magnetoencephalography/electroencephalography, functional magnetic resonance imaging) and models, e.g. using representational similarity analysis. We showcase two recent efforts that have been undertaken in this spirit and provide novel results about visual and auditory scene analysis. Finally, we discuss the limits of this perspective and sketch a concrete roadmap for future research. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044019

  6. Brain size and visual environment predict species differences in paper wasp sensory processing brain regions (hymenoptera: vespidae, polistinae).

    Science.gov (United States)

    O'Donnell, Sean; Clifford, Marie R; DeLeon, Sara; Papa, Christopher; Zahedi, Nazaneen; Bulova, Susan J

    2013-01-01

    The mosaic brain evolution hypothesis predicts that the relative volumes of functionally distinct brain regions will vary independently and correlate with species' ecology. Paper wasp species (Hymenoptera: Vespidae, Polistinae) differ in light exposure: they construct open versus enclosed nests and one genus (Apoica) is nocturnal. We asked whether light environments were related to species differences in the size of antennal and optic processing brain tissues. Paper wasp brains have anatomically distinct peripheral and central regions that process antennal and optic sensory inputs. We measured the volumes of 4 sensory processing brain regions in paper wasp species from 13 Neotropical genera including open and enclosed nesters, and diurnal and nocturnal species. Species differed in sensory region volumes, but there was no evidence for trade-offs among sensory modalities. All sensory region volumes correlated with brain size. However, peripheral optic processing investment increased with brain size at a higher rate than peripheral antennal processing investment. Our data suggest that mosaic and concerted (size-constrained) brain evolution are not exclusive alternatives. When brain regions increase with brain size at different rates, these distinct allometries can allow for differential investment among sensory modalities. As predicted by mosaic evolution, species ecology was associated with some aspects of brain region investment. Nest architecture variation was not associated with brain investment differences, but the nocturnal genus Apoica had the largest antennal:optic volume ratio in its peripheral sensory lobes. Investment in central processing tissues was not related to nocturnality, a pattern also noted in mammals. The plasticity of neural connections in central regions may accommodate evolutionary shifts in input from the periphery with relatively minor changes in volume.

  7. A new high-speed visual stimulation method for gaze-contingent eye movement and brain activity studies

    Directory of Open Access Journals (Sweden)

    Fabio eRichlan

    2013-07-01

    Full Text Available Approaches using eye movements as markers of ongoing brain activity to investigate perceptual and cognitive processes were able to implement highly sophisticated paradigms driven by eye movement recordings. Crucially, these paradigms involve display changes that have to occur during the time of saccadic blindness, when the subject is unaware of the change. Therefore, a combination of high-speed eye tracking and high-speed visual stimulation is required in these paradigms. For combined eye movement and brain activity studies (e.g., fMRI, EEG, MEG, fast and exact timing of display changes is especially important, because of the high susceptibility of these methods to visual stimulation. Eye tracking systems already achieve sampling rates up to 2000 Hz, but recent LCD technologies for computer screens reduced the temporal resolution to mostly 60 Hz, which is too slow for gaze-contingent display changes. We developed a high-speed video projection system, which is capable of reliably delivering display changes within the time frame of < 5 ms. This could not be achieved even with the fastest CRT monitors available (< 16 ms. The present video projection system facilitates the realization of cutting-edge eye movement research requiring reliable high-speed visual stimulation (e.g., gaze-contingent display changes, short-time presentation, masked priming. Moreover, this system can be used for fast visual presentation in order to assess brain activity using various methods, such as electroencephalography (EEG and functional magnetic resonance imaging (fMRI. The latter technique was previously excluded from high-speed visual stimulation, because it is not possible to operate conventional CRT monitors in the strong magnetic field of an MRI scanner. Therefore, the present video projection system offers new possibilities for studying eye movement-related brain activity using a combination of eye tracking and fMRI.

  8. Visualization of Time-Dependent Distribution of Rifampicin in Rat Brain Using MALDI MSI and Quantitative LCMS/MS.

    Science.gov (United States)

    Shobo, Adeola; Bratkowska, Dominika; Baijnath, Sooraj; Naiker, Suhashni; Bester, Linda A; Singh, Sanil D; Maguire, Glenn Eamond Mitchell; Kruger, Hendrik Gert; Govender, Thavendran

    2015-06-01

    Rifampicin (RIF) is a major component for short-course chemotherapy against tuberculosis, since it is active against rapidly metabolizing as well as dormant bacteria. According to the Lipinski rules, RIF should not enter the blood-brain barrier. Visualization of tissue drug distribution is of major importance in pharmacological studies; thus, far imaging of RIF in the brain has been limited to positron emission tomography. We propose using matrix-assisted laser desorption/ionization mass spectrometry imaging techniques as a suitable alternative for the visualization and localization of drug tissue distribution. Using the liquid chromatography mass spectrometric (LCMS) technique, we were able to quantify the concentrations of RIF in the uninfected rat brain; we paired this with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to show the time-dependent manner in which RIF is able to enter the brain. Our results show that even at the minute concentrations measured with LCMS/MS we were able visualize the drug and show its exact distribution in the rat brain. Other available methods require nuclear labeling and the detection of gamma rays produced by labeled compounds to visualize the compound and its localization; MALDI MSI is a more recently developed technique, which can provide detailed information on drug distribution in tissues when compared to other imaging techniques. This study shows that without any requirement for complex preprocessing we are able to produce images with a relatively improved resolution and localization than those acquired using more complex imaging methods, showing MALDI MSI to be an invaluable tool in drug distribution studies.

  9. Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex.

    Science.gov (United States)

    Scott, Gregory D; Karns, Christina M; Dow, Mark W; Stevens, Courtney; Neville, Helen J

    2014-01-01

    Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl's gyrus. In addition to reorganized auditory cortex (cross-modal plasticity), a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case), as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral vs. perifoveal visual stimulation (11-15° vs. 2-7°) in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl's gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl's gyrus) indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral vs. perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory, and multisensory and/or supramodal regions, such as posterior parietal cortex (PPC), frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal, and multisensory regions, to altered visual processing in congenitally deaf adults.

  10. Visualization of Active Glucocerebrosidase in Rodent Brain with High Spatial Resolution following In Situ Labeling with Fluorescent Activity Based Probes.

    Directory of Open Access Journals (Sweden)

    Daniela Herrera Moro Chao

    Full Text Available Gaucher disease is characterized by lysosomal accumulation of glucosylceramide due to deficient activity of lysosomal glucocerebrosidase (GBA. In cells, glucosylceramide is also degraded outside lysosomes by the enzyme glucosylceramidase 2 (GBA2 of which inherited deficiency is associated with ataxias. The interest in GBA and glucosylceramide metabolism in the brain has grown following the notion that mutations in the GBA gene impose a risk factor for motor disorders such as α-synucleinopathies. We earlier developed a β-glucopyranosyl-configured cyclophellitol-epoxide type activity based probe (ABP allowing in vivo and in vitro visualization of active molecules of GBA with high spatial resolution. Labeling occurs through covalent linkage of the ABP to the catalytic nucleophile residue in the enzyme pocket. Here, we describe a method to visualize active GBA molecules in rat brain slices using in vivo labeling. Brain areas related to motor control, like the basal ganglia and motor related structures in the brainstem, show a high content of active GBA. We also developed a β-glucopyranosyl cyclophellitol-aziridine ABP allowing in situ labeling of GBA2. Labeled GBA2 in brain areas can be identified and quantified upon gel electrophoresis. The distribution of active GBA2 markedly differs from that of GBA, being highest in the cerebellar cortex. The histological findings with ABP labeling were confirmed by biochemical analysis of isolated brain areas. In conclusion, ABPs offer sensitive tools to visualize active GBA and to study the distribution of GBA2 in the brain and thus may find application to establish the role of these enzymes in neurodegenerative disease conditions such as α-synucleinopathies and cerebellar ataxia.

  11. Alpha shape theory for 3D visualization and volumetric measurement of brain tumor progression using magnetic resonance images.

    Science.gov (United States)

    Hamoud Al-Tamimi, Mohammed Sabbih; Sulong, Ghazali; Shuaib, Ibrahim Lutfi

    2015-07-01

    Resection of brain tumors is a tricky task in surgery due to its direct influence on the patients' survival rate. Determining the tumor resection extent for its complete information via-à-vis volume and dimensions in pre- and post-operative Magnetic Resonance Images (MRI) requires accurate estimation and comparison. The active contour segmentation technique is used to segment brain tumors on pre-operative MR images using self-developed software. Tumor volume is acquired from its contours via alpha shape theory. The graphical user interface is developed for rendering, visualizing and estimating the volume of a brain tumor. Internet Brain Segmentation Repository dataset (IBSR) is employed to analyze and determine the repeatability and reproducibility of tumor volume. Accuracy of the method is validated by comparing the estimated volume using the proposed method with that of gold-standard. Segmentation by active contour technique is found to be capable of detecting the brain tumor boundaries. Furthermore, the volume description and visualization enable an interactive examination of tumor tissue and its surrounding. Admirable features of our results demonstrate that alpha shape theory in comparison to other existing standard methods is superior for precise volumetric measurement of tumor.

  12. Visualization and quantification of NAD(H) in brain sections by a novel histo-enzymatic nitrotetrazolium blue staining technique.

    Science.gov (United States)

    Balan, Irina S; Fiskum, Gary; Kristian, Tibor

    2010-02-26

    A histo-enzymatic technique for visualizing and quantifying endogenous NAD(H) in brain tissue was developed, based on coupled enzymatic cycling reactions that reduce nitrotetrazolium blue chloride to produce formazan. Conditions were used where the endogenous level of nicotinamide adenine dinucleotides (NAD(H)) was the rate limiting factor for formazan production. Spontaneous degradation of NAD(+) that occurs during incubation of thawed tissue was minimized by the addition of nicotinamide mononucleotide, an inhibitor of NAD(+) glycohydrolases. Cryostat sections of brains obtained from rats immediately after decapitation and 30 min later were used to determine the effects of ischemia alone on brain NAD(H) levels and neuroanatomic distribution. The ischemic insult resulted in a greater than 50% decline in the rate of formazan generation in the CA1 pyramidal neuronal layer of the hippocampus and in the parietal cortex and striatum, but not in the CA3 and dentate gyrus (DG) subregions of the hippocampus. The ischemia-induced changes in NAD(H) levels were confirmed by utilizing spectrofluorimetric measurements of NAD(H) present in perchloric acid extracts of brain samples. This new histo-enzymatic technique is suitable for visualizing and quantifying relative NAD(H) levels in the brain. This assay could prove useful in identifying region-selective NAD(H) catabolism that may contribute to neurodegeneration.

  13. A Fuzzy Integral Ensemble Method in Visual P300 Brain-Computer Interface

    Directory of Open Access Journals (Sweden)

    Francesco Cavrini

    2016-01-01

    Full Text Available We evaluate the possibility of application of combination of classifiers using fuzzy measures and integrals to Brain-Computer Interface (BCI based on electroencephalography. In particular, we present an ensemble method that can be applied to a variety of systems and evaluate it in the context of a visual P300-based BCI. Offline analysis of data relative to 5 subjects lets us argue that the proposed classification strategy is suitable for BCI. Indeed, the achieved performance is significantly greater than the average of the base classifiers and, broadly speaking, similar to that of the best one. Thus the proposed methodology allows realizing systems that can be used by different subjects without the need for a preliminary configuration phase in which the best classifier for each user has to be identified. Moreover, the ensemble is often capable of detecting uncertain situations and turning them from misclassifications into abstentions, thereby improving the level of safety in BCI for environmental or device control.

  14. Coding of visual object features and feature conjunctions in the human brain.

    Directory of Open Access Journals (Sweden)

    Jasna Martinovic

    Full Text Available Object recognition is achieved through neural mechanisms reliant on the activity of distributed coordinated neural assemblies. In the initial steps of this process, an object's features are thought to be coded very rapidly in distinct neural assemblies. These features play different functional roles in the recognition process--while colour facilitates recognition, additional contours and edges delay it. Here, we selectively varied the amount and role of object features in an entry-level categorization paradigm and related them to the electrical activity of the human brain. We found that early synchronizations (approx. 100 ms increased quantitatively when more image features had to be coded, without reflecting their qualitative contribution to the recognition process. Later activity (approx. 200-400 ms was modulated by the representational role of object features. These findings demonstrate that although early synchronizations may be sufficient for relatively crude discrimination of objects in visual scenes, they cannot support entry-level categorization. This was subserved by later processes of object model selection, which utilized the representational value of object features such as colour or edges to select the appropriate model and achieve identification.

  15. Image Data Mining for Pattern Classification and Visualization of Morphological Changes in Brain MR Images.

    Science.gov (United States)

    Murakawa, Saki; Ikuta, Rie; Uchiyama, Yoshikazu; Shiraishi, Junji

    2016-02-01

    Hospital information systems (HISs) and picture archiving and communication systems (PACSs) are archiving large amounts of data (i.e., "big data") that are not being used. Therefore, many research projects in progress are trying to use "big data" for the development of early diagnosis, prediction of disease onset, and personalized therapies. In this study, we propose a new method for image data mining to identify regularities and abnormalities in the large image data sets. We used 70 archived magnetic resonance (MR) images that were acquired using three-dimensional magnetization-prepared rapid acquisition with gradient echo (3D MP-RAGE). These images were obtained from the Alzheimer's disease neuroimaging initiative (ADNI) database. For anatomical standardization of the data, we used the statistical parametric mapping (SPM) software. Using a similarity matrix based on cross-correlation coefficients (CCs) calculated from an anatomical region and a hierarchical clustering technique, we classified all the abnormal cases into five groups. The Z score map identified the difference between a standard normal brain and each of those from the Alzheimer's groups. In addition, the scatter plot obtained from two similarity matrixes visualized the regularities and abnormalities in the image data sets. Image features identified using our method could be useful for understanding of image findings associated with Alzheimer's disease.

  16. Sub-Chronic Neuropathological and Biochemical Changes in Mouse Visual System after Repetitive Mild Traumatic Brain Injury

    OpenAIRE

    Radouil Tzekov; Clint Dawson; Megan Orlando; Benoit Mouzon; Jon Reed; James Evans; Gogce Crynen; Michael Mullan; Fiona Crawford

    2016-01-01

    Repetitive mild traumatic brain injury (r-mTBI) results in neuropathological and biochemical consequences in the human visual system. Using a recently developed mouse model of r-mTBI, with control mice receiving repetitive anesthesia alone (r-sham) we assessed the effects on the retina and optic nerve using histology, immunohistochemistry, proteomic and lipidomic analyses at 3 weeks post injury. Retina tissue was used to determine retinal ganglion cell (RGC) number, while optic nerve tissue w...

  17. Prosthetics & Orthotics Manufacturing Initiative (POMI)

    Science.gov (United States)

    2012-12-21

    regions either smeared unacceptably or the joint between the disparate regions was unacceptably weak during thermoforming events. The solution was to...The thin sheets were able to survive the thermoforming process and function as sensors. Prosthetics & Orthotics Manufacturing Initiative (POMI

  18. Prosthetic Hand Lifts Heavy Loads

    Science.gov (United States)

    Carden, James R.; Norton, William; Belcher, Jewell G.; Vest, Thomas W.

    1991-01-01

    Prosthetic hand designed to enable amputee to lift diverse heavy objects like rocks and logs. Has simple serrated end effector with no moving parts. Prosthesis held on forearm by system of flexible straps. Features include ruggedness, simplicity, and relatively low cost.

  19. Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation.

    Science.gov (United States)

    Wallentin, Mikkel; Skakkebæk, Anne; Bojesen, Anders; Fedder, Jens; Laurberg, Peter; Østergaard, John R; Hertz, Jens Michael; Pedersen, Anders Degn; Gravholt, Claus Højbjerg

    2016-01-01

    Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words "GREEN" or "RED" were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying "GREEN" or "RED" had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

  20. Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation

    Directory of Open Access Journals (Sweden)

    Mikkel Wallentin

    2016-01-01

    Full Text Available Klinefelter syndrome (47, XXY (KS is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49 responded to whether the words “GREEN” or “RED” were displayed in green or red (incongruent versus congruent colors. One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying “GREEN” or “RED” had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

  1. The remarkable visual capacities of nocturnal insects: vision at the limits with small eyes and tiny brains.

    Science.gov (United States)

    Warrant, Eric J

    2017-04-05

    Nocturnal insects have evolved remarkable visual capacities, despite small eyes and tiny brains. They can see colour, control flight and land, react to faint movements in their environment, navigate using dim celestial cues and find their way home after a long and tortuous foraging trip using learned visual landmarks. These impressive visual abilities occur at light levels when only a trickle of photons are being absorbed by each photoreceptor, begging the question of how the visual system nonetheless generates the reliable signals needed to steer behaviour. In this review, I attempt to provide an answer to this question. Part of the answer lies in their compound eyes, which maximize light capture. Part lies in the slow responses and high gains of their photoreceptors, which improve the reliability of visual signals. And a very large part lies in the spatial and temporal summation of these signals in the optic lobe, a strategy that substantially enhances contrast sensitivity in dim light and allows nocturnal insects to see a brighter world, albeit a slower and coarser one. What is abundantly clear, however, is that during their evolution insects have overcome several serious potential visual limitations, endowing them with truly extraordinary night vision.This article is part of the themed issue 'Vision in dim light'.

  2. Where does brain neural activation in aesthetic responses to visual art occur? Meta-analytic evidence from neuroimaging studies.

    Science.gov (United States)

    Boccia, M; Barbetti, S; Piccardi, L; Guariglia, C; Ferlazzo, F; Giannini, A M; Zaidel, D W

    2016-01-01

    Here we aimed at finding the neural correlates of the general aspect of visual aesthetic experience (VAE) and those more strictly correlated with the content of the artworks. We applied a general activation likelihood estimation (ALE) meta-analysis to 47 fMRI experiments described in 14 published studies. We also performed four separate ALE analyses in order to identify the neural substrates of reactions to specific categories of artworks, namely portraits, representation of real-world-visual-scenes, abstract paintings, and body sculptures. The general ALE revealed that VAE relies on a bilateral network of areas, and the individual ALE analyses revealed different maximal activation for the artworks' categories as function of their content. Specifically, different content-dependent areas of the ventral visual stream are involved in VAE, but a few additional brain areas are involved as well. Thus, aesthetic-related neural responses to art recruit widely distributed networks in both hemispheres including content-dependent brain areas of the ventral visual stream. Together, the results suggest that aesthetic responses are not independent of sensory, perceptual, and cognitive processes.

  3. Comparison of histological techniques to visualize iron in paraffin-embedded brain tissue of patients with Alzheimer's disease.

    Science.gov (United States)

    van Duijn, Sara; Nabuurs, Rob J A; van Duinen, Sjoerd G; Natté, Remco

    2013-11-01

    Better knowledge of the distribution of iron in the brains of Alzheimer's disease (AD) patients may facilitate the development of an in vivo magnetic resonance (MR) marker for AD and may cast light on the role of this potentially toxic molecule in the pathogenesis of AD. Several histological iron staining techniques have been used in the past but they have not been systematically tested for sensitivity and specificity. This article compares three histochemical techniques and ferritin immunohistochemistry to visualize iron in paraffin-embedded human AD brain tissue. The specificity of the histochemical techniques was tested by staining sections after iron extraction. Iron was demonstrated in the white matter, in layers IV/V of the frontal neocortex, in iron containing plaques, and in microglia. In our hands, these structures were best visualized using the Meguro iron stain, a method that has not been described for iron staining in human brain or AD in particular. Ferritin immunohistochemistry stained microglia and iron containing plaques similar to the Meguro method but was less intense in myelin-associated iron. The Meguro method is most suitable for identifying iron-positive structures in paraffin-embedded human AD brain tissue.

  4. A reconstructed digit by transplantation of a second toe for control of an electromechanical prosthetic hand.

    Science.gov (United States)

    Chen, Zhong Wei; Hu, Tian Pei

    2002-01-01

    The treatment options for the loss of an entire human hand and part of the forearm are currently limited to the transplantation of toe(s) to the amputation stump or a Krukenberg's bifurcation hand, and using a cosmetic or functional prosthesis. The functional prosthetic hand, such as the prevailing myoelectrically controlled prosthetic hand, has an action accuracy that is affected by many factors. The acceptance rate of the three planes freedom myoelectronic hand by the patients was 46-90% because of poor function caused by the weakness of signal and strong external interference. In this report, the left second toe was transplanted to the patient's forearm amputation stump. Mandates from the brain are relayed by the action of this reconstructed digit, to control a special designed multidimension freedom electronic prosthetic hand. After rehabilitation and adaptation training, the correct recognition rate of the electronic prosthetic hand controlled by this reconstructed digit is a remarkable 100%.

  5. Selective visual attention to drive cognitive brain machine interfaces: from concepts to neurofeedback and rehabilitation applications

    Directory of Open Access Journals (Sweden)

    Elaine eAstrand

    2014-08-01

    Full Text Available Brain Machine Interfaces (BMI using motor cortical activity to drive an external effector like a screen cursor or a robotic arm have seen enormous success and proven their great rehabilitation potential. An emerging parallel effort is now directed to BMIs controlled by endogenous cognitive activity, also called cognitive BMIs. While more challenging, this approach opens new dimensions to the rehabilitation of cognitive disorders. In the present work, we focus on BMIs driven by visuospatial attention signals and we provide a critical review of these studies in the light of the accumulated knowledge about the psychophysics, anatomy and neurophysiology of visual spatial attention. Importantly, we provide a unique comparative overview of the several studies, ranging from noninvasive to invasive human and non-human primates studies, that decode attention-related information from ongoing neuronal activity. We discuss these studies in the light of the challenges attention-driven cognitive BMIs have to face. In a second part of the review, we discuss past and current attention-based neurofeedback studies, describing both the covert effects of neurofeedback onto neuronal activity and its overt behavioral effects. Importantly, we compare neurofeedback studies based on the amplitude of cortical activity to studies based on the enhancement of cortical information content. Last, we discuss several lines of future research and applications for attention-driven cognitive BCIs, including the rehabilitation of cognitive deficits, restored communication in locked-in patients, and open-field applications for enhanced cognition in normal subjects. The core motivation of this work is the key idea that the improvement of current cognitive BMIs for therapeutic and open field applications needs to be grounded in a proper interdisciplinary understanding of the physiology of the cognitive function of interest, be it spatial attention, working memory or any other

  6. Visualizing the distribution of synapses from individual neurons in the mouse brain.

    Directory of Open Access Journals (Sweden)

    Ling Li

    Full Text Available BACKGROUND: Proper function of the mammalian brain relies on the establishment of highly specific synaptic connections among billions of neurons. To understand how complex neural circuits function, it is crucial to precisely describe neuronal connectivity and the distributions of synapses to and from individual neurons. METHODS AND FINDINGS: In this study, we present a new genetic synaptic labeling method that relies on expression of a presynaptic marker, synaptophysin-GFP (Syp-GFP in individual neurons in vivo. We assess the reliability of this method and use it to analyze the spatial patterning of synapses in developing and mature cerebellar granule cells (GCs. In immature GCs, Syp-GFP is distributed in both axonal and dendritic regions. Upon maturation, it becomes strongly enriched in axons. In mature GCs, we analyzed synapses along their ascending segments and parallel fibers. We observe no differences in presynaptic distribution between GCs born at different developmental time points and thus having varied depths of projections in the molecular layer. We found that the mean densities of synapses along the parallel fiber and the ascending segment above the Purkinje cell (PC layer are statistically indistinguishable, and higher than previous estimates. Interestingly, presynaptic terminals were also found in the ascending segments of GCs below and within the PC layer, with the mean densities two-fold lower than that above the PC layer. The difference in the density of synapses in these parts of the ascending segment likely reflects the regional differences in postsynaptic target cells of GCs. CONCLUSIONS: The ability to visualize synapses of single neurons in vivo is valuable for studying synaptogenesis and synaptic plasticity within individual neurons as well as information flow in neural circuits.

  7. Advancing the detection of steady-state visual evoked potentials in brain-computer interfaces

    Science.gov (United States)

    Abu-Alqumsan, Mohammad; Peer, Angelika

    2016-06-01

    Objective. Spatial filtering has proved to be a powerful pre-processing step in detection of steady-state visual evoked potentials and boosted typical detection rates both in offline analysis and online SSVEP-based brain-computer interface applications. State-of-the-art detection methods and the spatial filters used thereby share many common foundations as they all build upon the second order statistics of the acquired Electroencephalographic (EEG) data, that is, its spatial autocovariance and cross-covariance with what is assumed to be a pure SSVEP response. The present study aims at highlighting the similarities and differences between these methods. Approach. We consider the canonical correlation analysis (CCA) method as a basis for the theoretical and empirical (with real EEG data) analysis of the state-of-the-art detection methods and the spatial filters used thereby. We build upon the findings of this analysis and prior research and propose a new detection method (CVARS) that combines the power of the canonical variates and that of the autoregressive spectral analysis in estimating the signal and noise power levels. Main results. We found that the multivariate synchronization index method and the maximum contrast combination method are variations of the CCA method. All three methods were found to provide relatively unreliable detections in low signal-to-noise ratio (SNR) regimes. CVARS and the minimum energy combination methods were found to provide better estimates for different SNR levels. Significance. Our theoretical and empirical results demonstrate that the proposed CVARS method outperforms other state-of-the-art detection methods when used in an unsupervised fashion. Furthermore, when used in a supervised fashion, a linear classifier learned from a short training session is able to estimate the hidden user intention, including the idle state (when the user is not attending to any stimulus), rapidly, accurately and reliably.

  8. Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury

    DEFF Research Database (Denmark)

    Schow, Trine; Teasdale, Thomas William; Arendt Rasmussen, Morten

    2016-01-01

    Trine Schow, Thomas William Teasdale and Morten Arendt Rasmussen Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury. SOJ Psychology (in Press)......Trine Schow, Thomas William Teasdale and Morten Arendt Rasmussen Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury. SOJ Psychology (in Press)...

  9. Brain network involved in visual processing of movement stimuli used in upper limb robotic training: an fMRI study

    Directory of Open Access Journals (Sweden)

    Nocchi Federico

    2012-07-01

    Full Text Available Abstract Background The potential of robot-mediated therapy and virtual reality in neurorehabilitation is becoming of increasing importance. However, there is limited information, using neuroimaging, on the neural networks involved in training with these technologies. This study was intended to detect the brain network involved in the visual processing of movement during robotic training. The main aim was to investigate the existence of a common cerebral network able to assimilate biological (human upper limb and non-biological (abstract object movements, hence testing the suitability of the visual non-biological feedback provided by the InMotion2 Robot. Methods A visual functional Magnetic Resonance Imaging (fMRI task was administered to 22 healthy subjects. The task required observation and retrieval of motor gestures and of the visual feedback used in robotic training. Functional activations of both biological and non-biological movements were examined to identify areas activated in both conditions, along with differential activity in upper limb vs. abstract object trials. Control of response was also tested by administering trials with congruent and incongruent reaching movements. Results The observation of upper limb and abstract object movements elicited similar patterns of activations according to a caudo-rostral pathway for the visual processing of movements (including specific areas of the occipital, temporal, parietal, and frontal lobes. Similarly, overlapping activations were found for the subsequent retrieval of the observed movement. Furthermore, activations of frontal cortical areas were associated with congruent trials more than with the incongruent ones. Conclusions This study identified the neural pathway associated with visual processing of movement stimuli used in upper limb robot-mediated training and investigated the brain’s ability to assimilate abstract object movements with human motor gestures. In both conditions

  10. Effects of environmental contaminant exposure on visual brain development: a prospective electrophysiological study in school-aged children.

    Science.gov (United States)

    Ethier, Audrey-Anne; Muckle, Gina; Bastien, Célyne; Dewailly, Éric; Ayotte, Pierre; Arfken, Cynthia; Jacobson, Sandra W; Jacobson, Joseph L; Saint-Amour, Dave

    2012-10-01

    The Inuit from Nunavik (Northern Québec) are one of the most highly exposed populations to environmental contaminants in North America mainly due to the bioaccumulation of contaminants in fish and marine mammals that constitute an important part of their diet. This follow-up study aimed to assess the impact of exposure to contaminants on visual brain development in school-age Inuit children (mean age=10.9 years). Concentrations of polychlorinated biphenyls (PCBs), mercury (Hg), and lead (Pb) were measured in umbilical cord blood and again in blood samples at the time of testing, reflecting pre- and current exposure, respectively. Pattern-reversal visual evoked potentials (VEPs) were scalp-recorded at the occipital cortex. Visual stimulation consisted of achromatic gratings presented at four visual contrast levels: 95%, 30%, 12% and 4%. The relation between environmental contaminant body burdens and VEPs was examined by regression analysis controlling for confounding variables, including fish nutrients and other toxicants. No significant association was found for PCB exposure after statistical adjustments. Cord blood mercury level was associated with a reduction of the N75 amplitude at the highest contrast level and with a delay of the N75 latency at the 12% contrast level. Prenatal exposure to lead was associated with a delay of the N150 latency at most contrast levels. This study suggests that heavy metal exposure, in particular during the gestational period, can impair the development of visual processing.

  11. Parallel neural pathways in higher visual centers of the Drosophila brain that mediate wavelength-specific behavior

    Directory of Open Access Journals (Sweden)

    Hideo eOtsuna

    2014-02-01

    Full Text Available Compared with connections between the retinae and primary visual centers, relatively less is known in both mammals and insects about the functional segregation of neural pathways connecting primary and higher centers of the visual processing cascade. Here, using the Drosophila visual system as a model, we demonstrate two levels of parallel computation in the pathways that connect primary visual centers of the optic lobe to computational circuits embedded within deeper centers in the central brain. We show that a seemingly simple achromatic behavior, namely phototaxis, is under the control of several independent pathways, each of which is responsible for navigation towards unique wavelengths. Silencing just one pathway is enough to disturb phototaxis towards one characteristic monochromatic source, whereas phototactic behavior towards white light is not affected. The response spectrum of each demonstrable pathway is different from that of individual photoreceptors, suggesting subtractive computations. A choice assay between two colors showed that these pathways are responsible for navigation towards, but not for the detection itself of, the monochromatic light. The present study provides novel insights about how visual information is separated and processed in parallel to achieve robust control of an innate behavior.

  12. MoBILAB: An open source toolbox for analysis and visualization of mobile brain/body imaging data

    Directory of Open Access Journals (Sweden)

    Alejandro eOjeda

    2014-03-01

    Full Text Available A new paradigm for human brain imaging, mobile brain/body imaging (MoBI, involves synchronous collection of human brain activity (via electroencephalography, EEG and behavior (via body motion capture, eye tracking, etc., plus environmental events (scene and event recording to study joint brain/body dynamics supporting natural human cognition supporting performance of naturally motivated human actions and interactions in 3-D environments (Makeig et al., 2009⁠. Processing complex, concurrent, multi-modal, multi-rate data streams requires a signal-processing environment quite different from one designed to process single-modality time series data. Here we describe MoBILAB (more details available at sccn.ucsd.edu/wiki/MoBILAB, an open source, cross platform toolbox running on MATLAB (The Mathworks, Inc. that supports analysis and visualization of any mixture of synchronously recorded brain, behavioral, and environmental time series plus time-marked event stream data. MoBILAB can serve as a pre-processing environment for adding behavioral and other event markers to EEG data for further processing, and/or as a development platform for expanded analysis of simultaneously recorded data streams.

  13. Optical microangiography enabling visualization of change in meninges after traumatic brain injury in mice in vivo

    Science.gov (United States)

    Choi, Woo June; Qin, Wan; Qi, Xiaoli; Wang, Ruikang K.

    2016-03-01

    Traumatic brain injury (TBI) is a form of brain injury caused by sudden impact on brain by an external mechanical force. Following the damage caused at the moment of injury, TBI influences pathophysiology in the brain that takes place within the minutes or hours involving alterations in the brain tissue morphology, cerebral blood flow (CBF), and pressure within skull, which become important contributors to morbidity after TBI. While many studies for the TBI pathophysiology have been investigated with brain cortex, the effect of trauma on intracranial tissues has been poorly studied. Here, we report use of high-resolution optical microangiography (OMAG) to monitor the changes in cranial meninges beneath the skull of mouse after TBI. TBI is induced on a brain of anesthetized mouse by thinning the skull using a soft drill where a series of drilling exert mechanical stress on the brain through the skull, resulting in mild brain injury. Intracranial OMAG imaging of the injured mouse brain during post-TBI phase shows interesting pathophysiological findings in the meningeal layers such as widening of subdural space as well as vasodilation of subarachnoid vessels. These processes are acute and reversible within hours. The results indicate potential of OMAG to explore mechanism involved following TBI on small animals in vivo.

  14. Processing of visual gravitational motion in the peri-sylvian cortex: Evidence from brain-damaged patients.

    Science.gov (United States)

    Maffei, Vincenzo; Mazzarella, Elisabetta; Piras, Fabrizio; Spalletta, Gianfranco; Caltagirone, Carlo; Lacquaniti, Francesco; Daprati, Elena

    2016-05-01

    Rich behavioral evidence indicates that the brain estimates the visual direction and acceleration of gravity quite accurately, and the underlying mechanisms have begun to be unraveled. While the neuroanatomical substrates of gravity direction processing have been studied extensively in brain-damaged patients, to our knowledge no such study exists for the processing of visual gravitational motion. Here we asked 31 stroke patients to intercept a virtual ball moving along the vertical under either natural gravity or artificial reversed gravity. Twenty-seven of them also aligned a luminous bar to the vertical direction (subjective visual vertical, SVV). Using voxel-based lesion-symptom mapping as well as lesion subtraction analysis, we found that lesions mainly centered on the posterior insula are associated with greater deviations of SVV, consistent with several previous studies. Instead, lesions mainly centered on the parietal operculum decrease the ability to discriminate natural from unnatural gravitational acceleration with a timed motor response in the interception task. Both the posterior insula and the parietal operculum belong to the vestibular cortex, and presumably receive multisensory information about the gravity vector. We speculate that an internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of mechanical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, which are stored in the cortical vestibular network. The present lesion data suggest a specific role for the parietal operculum in detecting the mismatch between predictive signals from the internal model and the online visual signals.

  15. Changes in visual perspective influence brain activity patterns during cognitive perspective-taking of other people's pain.

    Science.gov (United States)

    Vistoli, Damien; Achim, Amélie M; Lavoie, Marie-Audrey; Jackson, Philip L

    2016-05-01

    Empathy refers to our capacity to share and understand the emotional states of others. It relies on two main processes according to existing models: an effortless affective sharing process based on neural resonance and a more effortful cognitive perspective-taking process enabling the ability to imagine and understand how others feel in specific situations. Until now, studies have focused on factors influencing the affective sharing process but little is known about those influencing the cognitive perspective-taking process and the related brain activations during vicarious pain. In the present fMRI study, we used the well-known physical pain observation task to examine whether the visual perspective can influence, in a bottom-up way, the brain regions involved in taking others' cognitive perspective to attribute their level of pain. We used a pseudo-dynamic version of this classic task which features hands in painful or neutral daily life situations while orthogonally manipulating: (1) the visual perspective with which hands were presented (first-person versus third-person conditions) and (2) the explicit instructions to imagine oneself or an unknown person in those situations (Self versus Other conditions). The cognitive perspective-taking process was investigated by comparing Other and Self conditions. When examined across both visual perspectives, this comparison showed no supra-threshold activation. Instead, the Other versus Self comparison led to a specific recruitment of the bilateral temporo-parietal junction when hands were presented according to a first-person (but not third-person) visual perspective. The present findings identify the visual perspective as a factor that modulates the neural activations related to cognitive perspective-taking during vicarious pain and show that this complex cognitive process can be influenced by perceptual stages of information processing.

  16. Real-time fMRI brain-computer interface: development of a “motivational feedback” subsystem for the regulation of visual cue reactivity

    OpenAIRE

    2014-01-01

    Here we present a novel neurofeedback subsystem for the presentation of motivationally relevant visual feedback during the self-regulation of functional brain activation. Our “motivational neurofeedback” approach uses functional magnetic resonance imaging (fMRI) signals elicited by visual cues (pictures) and related to motivational processes such as craving or hunger. The visual feedback subsystem provides simultaneous feedback through these images as their size corresponds to the magnitude o...

  17. Contralateral cortical organisation of information in visual short-term memory: evidence from lateralized brain activity during retrieval.

    Science.gov (United States)

    Fortier-Gauthier, Ulysse; Moffat, Nicolas; Dell'Acqua, Roberto; McDonald, John J; Jolicœur, Pierre

    2012-07-01

    We studied brain activity during retention and retrieval phases of two visual short-term memory (VSTM) experiments. Experiment 1 used a balanced memory array, with one color stimulus in each hemifield, followed by a retention interval and a central probe, at the fixation point that designated the target stimulus in memory about which to make a determination of orientation. Retrieval of information from VSTM was associated with an event-related lateralization (ERL) with a contralateral negativity relative to the visual field from which the probed stimulus was originally encoded, suggesting a lateralized organization of VSTM. The scalp distribution of the retrieval ERL was more anterior than what is usually associated with simple maintenance activity, which is consistent with the involvement of different brain structures for these distinct visual memory mechanisms. Experiment 2 was like Experiment 1, but used an unbalanced memory array consisting of one lateral color stimulus in a hemifield and one color stimulus on the vertical mid-line. This design enabled us to separate lateralized activity related to target retrieval from distractor processing. Target retrieval was found to generate a negative-going ERL at electrode sites found in Experiment 1, and suggested representations were retrieved from anterior cortical structures. Distractor processing elicited a positive-going ERL at posterior electrodes sites, which could be indicative of a return to baseline of retention activity for the discarded memory of the now-irrelevant stimulus, or an active inhibition mechanism mediating distractor suppression.

  18. Evaluation of an Acute RNAi-Mediated Therapeutic for Visual Dysfunction Associated with Traumatic Brain Injury

    Science.gov (United States)

    2013-10-01

    brain injury (TBI) is the leading cause of death in children and young adults globally. Malignant cerebral edema plays a major role in the...pathophysiology which evolves after severe TBI. Added to this is the significant morbidity and mortality from cerebral edema associated with acute stroke...hypoxic ischemic coma, neurological cancers and brain infection. Therapeutic strategies to prevent cerebral edema are limited and if brain swelling

  19. Visual awareness suppression by pre-stimulus brain stimulation; a neural effect.

    Science.gov (United States)

    Jacobs, Christianne; Goebel, Rainer; Sack, Alexander T

    2012-01-02

    Transcranial magnetic stimulation (TMS) has established the functional relevance of early visual cortex (EVC) for visual awareness with great temporal specificity non-invasively in conscious human volunteers. Many studies have found a suppressive effect when TMS was applied over EVC 80-100 ms after the onset of the visual stimulus (post-stimulus TMS time window). Yet, few studies found task performance to also suffer when TMS was applied even before visual stimulus presentation (pre-stimulus TMS time window). This pre-stimulus TMS effect, however, remains controversially debated and its origin had mainly been ascribed to TMS-induced eye-blinking artifacts. Here, we applied chronometric TMS over EVC during the execution of a visual discrimination task, covering an exhaustive range of visual stimulus-locked TMS time windows ranging from -80 pre-stimulus to 300 ms post-stimulus onset. Electrooculographical (EoG) recordings, sham TMS stimulation, and vertex TMS stimulation controlled for different types of non-neural TMS effects. Our findings clearly reveal TMS-induced masking effects for both pre- and post-stimulus time windows, and for both objective visual discrimination performance and subjective visibility. Importantly, all effects proved to be still present after post hoc removal of eye blink trials, suggesting a neural origin for the pre-stimulus TMS suppression effect on visual awareness. We speculate based on our data that TMS exerts its pre-stimulus effect via generation of a neural state which interacts with subsequent visual input.

  20. Validation of the prosthetic esthetic index

    DEFF Research Database (Denmark)

    Özhayat, Esben B; Dannemand, Katrine

    2014-01-01

    OBJECTIVES: In order to diagnose impaired esthetics and evaluate treatments for these, it is crucial to evaluate all aspects of oral and prosthetic esthetics. No professionally administered index currently exists that sufficiently encompasses comprehensive prosthetic esthetics. This study aimed...... to validate a new comprehensive index, the Prosthetic Esthetic Index (PEI), for professional evaluation of esthetics in prosthodontic patients. MATERIAL AND METHODS: The content, criterion, and construct validity; the test-retest, inter-rater, and internal consistency reliability; and the sensitivity...

  1. Fiber-array based optogenetic prosthetic system for stimulation therapy

    Science.gov (United States)

    Gu, Ling; Cote, Chris; Tejeda, Hector; Mohanty, Samarendra

    2012-02-01

    Recent advent of optogenetics has enabled activation of genetically-targeted neuronal cells using low intensity blue light with high temporal precision. Since blue light is attenuated rapidly due to scattering and absorption in neural tissue, optogenetic treatment of neurological disorders may require stimulation of specific cell types in multiple regions of the brain. Further, restoration of certain neural functions (vision, and auditory etc) requires accurate spatio-temporal stimulation patterns rather than just precise temporal stimulation. In order to activate multiple regions of the central nervous system in 3D, here, we report development of an optogenetic prosthetic comprising of array of fibers coupled to independently-controllable LEDs. This design avoids direct contact of LEDs with the brain tissue and thus does not require electrical and heat isolation, which can non-specifically stimulate and damage the local brain regions. The intensity, frequency, and duty cycle of light pulses from each fiber in the array was controlled independently using an inhouse developed LabView based program interfaced with a microcontroller driving the individual LEDs. While the temporal profile of the light pulses was controlled by varying the current driving the LED, the beam profile emanating from each fiber tip could be sculpted by microfabrication of the fiber tip. The fiber array was used to stimulate neurons, expressing channelrhodopsin-2, in different locations within the brain or retina. Control of neural activity in the mice cortex, using the fiber-array based prosthetic, is evaluated from recordings made with multi-electrode array (MEA). We also report construction of a μLED array based prosthetic for spatio-temporal stimulation of cortex.

  2. Circuit For Control Of Electromechanical Prosthetic Hand

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Proposed circuit for control of electromechanical prosthetic hand derives electrical control signals from shoulder movements. Updated, electronic version of prosthesis, that includes two hooklike fingers actuated via cables from shoulder harness. Circuit built around favored shoulder harness, provides more dexterous movement, without incurring complexity of computer-controlled "bionic" or hydraulically actuated devices. Additional harness and potentiometer connected to similar control circuit mounted on other shoulder. Used to control stepping motor rotating hand about prosthetic wrist to one of number of angles consistent with number of digital outputs. Finger-control signals developed by circuit connected to first shoulder harness transmitted to prosthetic hand via sliprings at prosthetic wrist joint.

  3. Computer Aided Facial Prosthetics Manufacturing System

    Directory of Open Access Journals (Sweden)

    Peng H.K.

    2016-01-01

    Full Text Available Facial deformities can impose burden to the patient. There are many solutions for facial deformities such as plastic surgery and facial prosthetics. However, current fabrication method of facial prosthetics is high-cost and time consuming. This study aimed to identify a new method to construct a customized facial prosthetic. A 3D scanner, computer software and 3D printer were used in this study. Results showed that the new developed method can be used to produce a customized facial prosthetics. The advantages of the developed method over the conventional process are low cost, reduce waste of material and pollution in order to meet the green concept.

  4. Prosthetic Frequently Asked Questions for the New Amputee

    Science.gov (United States)

    ... Resource Center > Prosthetic FAQs for the New Amputee Prosthetic FAQs for the New Amputee Web Development June ... HELPFUL TO SPEAK WITH OTHERS WHO USE A PROSTHETIC DEVICE? Don’t underestimate the value of talking ...

  5. Tolerability and Effectiveness of Contact Lenses in Mild Traumatic Brain Injury with Visual Discomfort: A Case Series

    Directory of Open Access Journals (Sweden)

    Len V. Hua, PhD

    2014-01-01

    Full Text Available Background: Over one million people in the United States annually have traumatic incidents that lead to traumatic brain injury (TBI. Asthenopia or eyestrain is frequently a clinical complaint with TBI patients. However, little is studied or known in the literature about the potential of contact lens correction in the management of mild TBI (mTBI with accommodative dysfunction. This pilot study examines the tolerability, effectiveness, and clinical utility of multifocal contact lenses in a subset of mTBI patients with visual discomfort. Methods: This was a controlled, crossover study using Proclear EP Multifocal contact lenses, compared to Proclear Single Vision contact lenses, for five subjects between the ages of 24 and 31 years of age with history of mTBI. Visual symptoms were evaluated using the Convergence Insufficiency Symptom Survey. Visual function was examined by standard visual tests, including visual acuity, extraocular motility (EOM, pupil size, near point of convergence (NPC, vergence, phoria, NRA/PRA, accommodative and vergence facility, and stereoacuity. Subjects were randomized to wear either Proclear Sphere (single vision or Proclear EP Multifocal contact lenses, each for a duration of two weeks. Results: Five mTBI subjects were enrolled in the study. Comprehensive vision examinations of all subjects prior to the study revealed normal ocular health with the exception of visual symptoms such as eyestrain and headache. Two subjects appreciated the beneficial effects of multifocal contact lenses. The other three subjects did not experience substantial benefits of multifocal contact lenses. Nevertheless, all subjects successfully tolerated daylong contact lens wear. Conclusions: Most eye care professionals face the daunting task of how best to manage complex mTBI cases. One of the lingering effects of TBI is often visual symptoms due to oculomotor dysfunction. Multiple treatment modalities may be necessary to alleviate chronic visual

  6. Single trial predictors for gating motor-imagery brain-computer interfaces based on sensorimotor rhythm and visual evoked potentials

    Directory of Open Access Journals (Sweden)

    Andrew eGeronimo

    2016-04-01

    Full Text Available For brain-computer interfaces (BCIs that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of ongoing processes, visual evoked responses, and voluntary modulation. We proposed to use three brain signatures for predicting success on a single trial of a BCI task. The first two features, the amplitude and phase of the pre-trial mu amplitude, were chosen as a correlate for cortical excitability. The remaining feature, related to the visually evoked response to the cue, served as a possible measure of fixation and attention to the task. Of these three features, mu rhythm amplitude over the central electrodes at the time of cue presentation and to a lesser extent the single trial visual evoked response were correlated with the success on the subsequent imagery task. Despite the potential for gating trials using these features, an offline gating simulation was limited in its ability to produce an increase in device throughput. This discrepancy highlights a distinction between the identification of predictive features, and the use of this knowledge in an online BCI. Using such a system, we cannot assume that the user will respond similarly when faced with a scenario where feedback is altered by trials that are gated on a regular basis. The results of this study suggest the possibility of using individualized, pre-task neural signatures for personalized and asynchronous (self-paced BCI applications, although these effects need to be quantified in a real-time adaptive scenario in a future study.

  7. Neuroengineering tools/applications for bidirectional interfaces, brain-computer interfaces, and neuroprosthetic implants - a review of recent progress.

    Science.gov (United States)

    Rothschild, Ryan Mark

    2010-01-01

    The main focus of this review is to provide a holistic amalgamated overview of the most recent human in vivo techniques for implementing brain-computer interfaces (BCIs), bidirectional interfaces, and neuroprosthetics. Neuroengineering is providing new methods for tackling current difficulties; however neuroprosthetics have been studied for decades. Recent progresses are permitting the design of better systems with higher accuracies, repeatability, and system robustness. Bidirectional interfaces integrate recording and the relaying of information from and to the brain for the development of BCIs. The concepts of non-invasive and invasive recording of brain activity are introduced. This includes classical and innovative techniques like electroencephalography and near-infrared spectroscopy. Then the problem of gliosis and solutions for (semi-) permanent implant biocompatibility such as innovative implant coatings, materials, and shapes are discussed. Implant power and the transmission of their data through implanted pulse generators and wireless telemetry are taken into account. How sensation can be relayed back to the brain to increase integration of the neuroengineered systems with the body by methods such as micro-stimulation and transcranial magnetic stimulation are then addressed. The neuroprosthetic section discusses some of the various types and how they operate. Visual prosthetics are discussed and the three types, dependant on implant location, are examined. Auditory prosthetics, being cochlear or cortical, are then addressed. Replacement hand and limb prosthetics are then considered. These are followed by sections concentrating on the control of wheelchairs, computers and robotics directly from brain activity as recorded by non-invasive and invasive techniques.

  8. Visual hallucinations of autobiographic memory and asomatognosia: a case of epilepsy due to brain cysticercosis.

    Science.gov (United States)

    Orjuela-Rojas, Juan Manuel; Ramírez-Bermúdez, Jesús; Martínez-Juárez, Iris E; Kerik, Nora Estela; Diaz Meneses, Iván; Pérez-Gay, Fernanda Juárez

    2015-01-01

    The current study describes the case of a woman with symptomatic epilepsy due to brain cysticercosis acquired during childhood. During her adolescence, she developed seizures characterized by metamorphopsia, hallucinations of autobiographic memory and, finally, asomatognosia. Magnetic brain imaging showed a calcified lesion in the right occipitotemporal cortex, and positron emission tomography imaging confirmed the presence of interictal hypometabolism in two regions: the right parietal cortex and the right lateral and posterior temporal cortex. We discuss the link between these brain areas and the symptoms described under the concepts of epileptogenic lesion, epileptogenic zone, functional deficit zone, and symptomatogenic zone.

  9. Smartphones as image processing systems for prosthetic vision.

    Science.gov (United States)

    Zapf, Marc P; Matteucci, Paul B; Lovell, Nigel H; Suaning, Gregg J

    2013-01-01

    The feasibility of implants for prosthetic vision has been demonstrated by research and commercial organizations. In most devices, an essential forerunner to the internal stimulation circuit is an external electronics solution for capturing, processing and relaying image information as well as extracting useful features from the scene surrounding the patient. The capabilities and multitude of image processing algorithms that can be performed by the device in real-time plays a major part in the final quality of the prosthetic vision. It is therefore optimal to use powerful hardware yet to avoid bulky, straining solutions. Recent publications have reported of portable single-board computers fast enough for computationally intensive image processing. Following the rapid evolution of commercial, ultra-portable ARM (Advanced RISC machine) mobile devices, the authors investigated the feasibility of modern smartphones running complex face detection as external processing devices for vision implants. The role of dedicated graphics processors in speeding up computation was evaluated while performing a demanding noise reduction algorithm (image denoising). The time required for face detection was found to decrease by 95% from 2.5 year old to recent devices. In denoising, graphics acceleration played a major role, speeding up denoising by a factor of 18. These results demonstrate that the technology has matured sufficiently to be considered as a valid external electronics platform for visual prosthetic research.

  10. NIRS monitoring of muscle contraction to control a prosthetic device

    Science.gov (United States)

    Bianchi, Thomas; Zambarbieri, Daniela; Beltrami, Giorgio; Verni, Gennaro

    1999-01-01

    The fitting of upper-extremity amputees requires special efforts, and its significance has been increased by the development of the myoelectrically controlled prosthetic arm. This solution is not free of problems due to the nature of the amputation, to the electromagnetic noise affecting the myelectrical signal and to the perspiration due to the contact between socket and the residual limb. Starting from the fact that NIRS and electromyographic signals are similar during a muscle contraction, we have first studied the NIRS signal during forearm muscle contractions in normal and amputee subjects. Then a new system to interface the NIRS unit and the myoelectrical prosthetic hand has been developed. The NIRS unit has been used as optical sensor and all the operations (I/O and signal processing) are performed via software. This system has been tested on normal and amputee subjects performing hand grasping using a visual biofeedback control scheme. All the subjects have been able to perform these operations demonstrating the NIRS technique. This could represent an alternative solution for controlling a prosthetic device.

  11. Providing a sense of touch to prosthetic hands.

    Science.gov (United States)

    Nghiem, Bao Tram; Sando, Ian C; Gillespie, R Brent; McLaughlin, Bryan L; Gerling, Gregory J; Langhals, Nicholas B; Urbanchek, Melanie G; Cederna, Paul S

    2015-06-01

    Each year, approximately 185,000 Americans suffer the devastating loss of a limb. The effects of upper limb amputations are profound because a person's hands are tools for everyday functioning, expressive communication, and other uniquely human attributes. Despite the advancements in prosthetic technology, current upper limb prostheses are still limited in terms of complex motor control and sensory feedback. Sensory feedback is critical to restoring full functionality to amputated patients because it would relieve the cognitive burden of relying solely on visual input to monitor motor commands and provide tremendous psychological benefits. This article reviews the latest innovations in sensory feedback and argues in favor of peripheral nerve interfaces. First, the authors examine the structure of the peripheral nerve and its importance in the development of a sensory interface. Second, the authors discuss advancements in targeted muscle reinnervation and direct neural stimulation by means of intraneural electrodes. The authors then explore the future of prosthetic sensory feedback using innovative technologies for neural signaling, specifically, the sensory regenerative peripheral nerve interface and optogenetics. These breakthroughs pave the way for the development of a prosthetic limb with the ability to feel.

  12. A visual pathway links brain structures active during magnetic compass orientation in migratory birds.

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    Dominik Heyers

    Full Text Available The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, "Cluster N", show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds "see" the reference compass direction provided by the geomagnetic field.

  13. A visual pathway links brain structures active during magnetic compass orientation in migratory birds.

    Science.gov (United States)

    Heyers, Dominik; Manns, Martina; Luksch, Harald; Güntürkün, Onur; Mouritsen, Henrik

    2007-09-26

    The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, "Cluster N", show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds "see" the reference compass direction provided by the geomagnetic field.

  14. Rotationally actuated prosthetic helping hand

    Science.gov (United States)

    Norton, William E. (Inventor); Belcher, Jewell G., Jr. (Inventor); Carden, James R. (Inventor); West, Thomas W. (Inventor)

    1991-01-01

    A prosthetic device has been developed for below-the-elbow amputees. The device consists of a cuff, a stem, a housing, two hook-like fingers, an elastic band for holding the fingers together, and a brace. The fingers are pivotally mounted on a housing that is secured to the amputee's upper arm with the brace. The stem, which also contains a cam, is rotationally mounted within the housing and is secured to the cuff, which fits over the amputee's stump. By rotating the cammed stem between the fingers with the lower arm, the amputee can open and close the fingers.

  15. Molecular Evidence for Convergence and Parallelism in Evolution of Complex Brains of Cephalopod Molluscs: Insights from Visual Systems.

    Science.gov (United States)

    Yoshida, M A; Ogura, A; Ikeo, K; Shigeno, S; Moritaki, T; Winters, G C; Kohn, A B; Moroz, L L

    2015-12-01

    Coleoid cephalopods show remarkable evolutionary convergence with vertebrates in their neural organization, including (1) eyes and visual system with optic lobes, (2) specialized parts of the brain controlling learning and memory, such as vertical lobes, and (3) unique vasculature supporting such complexity of the central nervous system. We performed deep sequencing of eye transcriptomes of pygmy squids (Idiosepius paradoxus) and chambered nautiluses (Nautilus pompilius) to decipher the molecular basis of convergent evolution in cephalopods. RNA-seq was complemented by in situ hybridization to localize the expression of selected genes. We found three types of genomic innovations in the evolution of complex brains: (1) recruitment of novel genes into morphogenetic pathways, (2) recombination of various coding and regulatory regions of different genes, often called "evolutionary tinkering" or "co-option", and (3) duplication and divergence of genes. Massive recruitment of novel genes occurred in the evolution of the "camera" eye from nautilus' "pinhole" eye. We also showed that the type-2 co-option of transcription factors played important roles in the evolution of the lens and visual neurons. In summary, the cephalopod convergent morphological evolution of the camera eyes was driven by a mosaic of all types of gene recruitments. In addition, our analysis revealed unexpected variations of squids' opsins, retinochromes, and arrestins, providing more detailed information, valuable for further research on intra-ocular and extra-ocular photoreception of the cephalopods.

  16. Compass Cells in the Brain of an Insect Are Sensitive to Novel Events in the Visual World.

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    Tobias Bockhorst

    Full Text Available The central complex of the insect brain comprises a group of neuropils involved in spatial orientation and memory. In fruit flies it mediates place learning based on visual landmarks and houses neurons that encode the orientation for goal-directed locomotion, based on landmarks and self-motion cues for angular path-integration. In desert locusts, the central complex holds a compass-like representation of head directions, based on the polarization pattern of skylight. Through intracellular recordings from immobilized locusts, we investigated whether sky compass neurons of the central complex also represent the position or any salient feature of possible landmarks, in analogy to the observations in flies. Neurons showed strongest responses to the novel appearance of a small moving square, but we found no evidence for a topographic representation of object positions. Responses to an individual square were independent of direction of motion and trajectory, but showed rapid adaptation to successive stimulation, unaffected by changing the direction of motion. Responses reappeared, however, if the moving object changed its trajectory or if it suddenly reversed moving direction against the movement of similar objects that make up a coherent background-flow as induced by ego-motion. Response amplitudes co-varied with the precedent state of dynamic background activity, a phenomenon that has been related to attention-dependent saliency coding in neurons of the mammalian primary visual cortex. The data show that neurons of the central complex of the locust brain are visually bimodal, signaling sky compass direction and the novelty character of moving objects. These response properties might serve to attune compass-aided locomotor control to unexpected events in the environment. The difference to data obtained in fruit flies might relate to differences in the lifestyle of landmark learners (fly and compass navigators (locust, point to the existence of

  17. Design and Analysis of New Prosthetic Foot.

    Directory of Open Access Journals (Sweden)

    Kadhim K.Al-Kinani,MSc

    2007-01-01

    Full Text Available There is a variety of artificial foot designs variable for use with prosthetic legs . Most of the design can be divided into two classes, articulated and non-articulated feet. one common non-articulated foot is the SACH . The solid ankle cushion heel foot referred to as the SACH foot has a rigid keelOne key or the key factor in designing a new prosthesis is in the analysis of a patients response This view is the most important because if the foot does not provide functional , practical or cosmetically acceptable characteristics the patient will not feel comfortable with the prosthesis , therefore design and manufacturing a new foot is essential, this foot made from polyethylene, its different shape and characteristics The characteristics deemed important by patients in achieving natural gait motion include:Dorsiflexion Energy return Fatigue test In this study, including all these characteristics test, design fatigue foot tester according to ISO 10328 and design new foot .Also, the testometric crosshead was modified to find dorsiflexion angle and energy return .The fatigue criteria for polymer was proposed, in mathematical solution. Finally , the characteristics of SACH foot was compared with new foot by mathematical solution and used visual basic program and experimental method by different tests. From these test that the new foot is better than SACH foot for all test .

  18. Autoradiographic visualization of insulin-like growth factor-II receptors in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsohn, L.G.; Kerchner, G.A.; Clemens, J.A.; Smith, M.C.

    1986-03-01

    The documented presence of IGF-II in brain and CSF prompted us to investigate the distribution of receptors for IGF-II in rat brain slices. Human /sup 125/-I-IGF-II (10 pM) was incubated for 16 hrs at 4/sup 0/C with slide-mounted rat brain slices in the absence and presence of unlabeled human IGF-II (67 nM) or human insulin (86 nM). Slides were washed, dried, and exposed to X-ray film for 4-7 days. The results showed dense labeling in the granular layers of the olfactory bulbs, deep layers of the cerebral cortex, pineal gland, anterior pituitary, hippocampus (pyramidal cells CA/sub 1/-CA/sub 2/ and dentate gyrus), and the granule cell layers of the cerebellum. Unlabeled IGF-II eliminated most of the binding of these brain regions while insulin produced only a minimal reduction in the amount of /sup 125/I-IGF-II bound. These results indicate that a specific neural receptor for IGS-II is uniquely distributed in rat brain tissue and supports the notion that this peptide might play an important role in normal neuronal functioning.

  19. Cochlear Implant Using Neural Prosthetics

    Science.gov (United States)

    Gupta, Shweta; Singh, Shashi kumar; Dubey, Pratik Kumar

    2012-10-01

    This research is based on neural prosthetic device. The oldest and most widely used of these electrical, and often computerized, devices is the cochlear implant, which has provided hearing to thousands of congenitally deaf people in this country. Recently, the use of the cochlear implant is expanding to the elderly, who frequently suffer major hearing loss. More cutting edge are artificial retinas, which are helping dozens of blind people see, and ìsmartî artificial arms and legs that amputees can maneuver by thoughts alone, and that feel more like real limbs.Research, which curiosity led to explore frog legs dancing during thunderstorms, a snail shapedorgan in the inner ear, and how various eye cells react to light, have fostered an understanding of how to ìtalkî to the nervous system. That understanding combined with the miniaturization of electronics and enhanced computer processing has enabled prosthetic devices that often can bridge the gap in nerve signaling that is caused by disease or injury.

  20. Higher Brain Functions Served by the Lowly Rodent Primary Visual Cortex

    Science.gov (United States)

    Gavornik, Jeffrey P.; Bear, Mark F.

    2014-01-01

    It has been more than 50 years since the first description of ocular dominance plasticity--the profound modification of primary visual cortex (V1) following temporary monocular deprivation. This discovery immediately attracted the intense interest of neurobiologists focused on the general question of how experience and deprivation modify the brain…

  1. Holistic face categorization in higher-level cortical visual areas of the normal and prosopagnosic brain: towards a non-hierarchical view of face perception

    Directory of Open Access Journals (Sweden)

    Bruno Rossion

    2011-01-01

    Full Text Available How a visual stimulus is initially categorized as a face in a network of human brain areas remains largely unclear. Hierarchical neuro-computational models of face perception assume that the visual stimulus is first decomposed in local parts in lower order visual areas. These parts would then be combined into a global representation in higher order face-sensitive areas of the occipito-temporal cortex. Here we tested this view in fMRI with visual stimuli that are categorized as faces based on their global configuration rather than their local parts (2-tones Mooney figures and Arcimboldo’s facelike paintings. Compared to the same inverted visual stimuli that are not categorized as faces, these stimuli activated the right middle fusiform gyrus (Fusiform face area, FFA and superior temporal sulcus (pSTS, with no significant activation in the posteriorly located inferior occipital gyrus (i.e., no occipital face area, OFA. This observation is strengthened by behavioral and neural evidence for normal face categorization of these stimuli in a brain-damaged prosopagnosic patient (PS whose intact right middle fusiform gyrus and superior temporal sulcus are devoid of any potential face-sensitive inputs from the lesioned right inferior occipital cortex. Together, these observations indicate that face-preferential activation may emerge in higher order visual areas of the right hemisphere without any face-preferential inputs from lower order visual areas, supporting a non-hierarchical view of face perception in the visual cortex.

  2. Visualization of damaged brain tissue after ischemic stroke with cobalt-55 positron emission tomography

    NARCIS (Netherlands)

    Jansen, H M; Pruim, J; vd Vliet, A M; Paans, A M; Hew, J M; Franssen, E J; de Jong, B M; Kosterink, J G; Haaxma, R; Korf, J

    1994-01-01

    UNLABELLED: In animal experiments, the radionuclide 55Co2+ has been shown to accumulate in degenerating cerebral tissue similar to Ca2+. METHODS: The potential role of 55Co2+ for in vivo brain PET imaging was investigated in four patients after ischemic stroke. RESULTS: PET showed uptake of 55Co2+ i

  3. Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment.

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    Ryogo Minamimoto

    Full Text Available The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis.A total of 73 brain lesions (glioma: 31, brain metastasis: 42 in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex. The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N ratio of MET uptake.Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89 or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89, which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment.The visual assessment showed no significant difference from quantitative assessment of MET

  4. Prosthetic

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    Pokpong Amornvit

    2014-01-01

    Full Text Available Ocular trauma can be caused by road traffic accidents, falls, assaults, or work-related accidents. Enucleation is often indicated after ocular injury or for the treatment of intraocular tumors, severe ocular infections, and painful blind eyes. Rehabilitation of an enucleated socket without an intraocular implant or with an inappropriately sized implant can result in superior sulcus deepening, enophthalmos, ptosis, ectropion, and lower lid laxity, which are collectively known as post-enucleation socket syndrome. This clinical report describes the rehabilitation of post-enucleation socket syndrome with a modified ocular prosthesis. Modifications to the ocular prosthesis were performed to correct the ptosis, superior sulcus deepening, and enophthalmos. The rehabilitation procedure produced satisfactory results.

  5. Large Scale Functional Brain Networks Underlying Temporal Integration of Audio-Visual Speech Perception: An EEG Study.

    Science.gov (United States)

    Kumar, G Vinodh; Halder, Tamesh; Jaiswal, Amit K; Mukherjee, Abhishek; Roy, Dipanjan; Banerjee, Arpan

    2016-01-01

    Observable lip movements of the speaker influence perception of auditory speech. A classical example of this influence is reported by listeners who perceive an illusory (cross-modal) speech sound (McGurk-effect) when presented with incongruent audio-visual (AV) speech stimuli. Recent neuroimaging studies of AV speech perception accentuate the role of frontal, parietal, and the integrative brain sites in the vicinity of the superior temporal sulcus (STS) for multisensory speech perception. However, if and how does the network across the whole brain participates during multisensory perception processing remains an open question. We posit that a large-scale functional connectivity among the neural population situated in distributed brain sites may provide valuable insights involved in processing and fusing of AV speech. Varying the psychophysical parameters in tandem with electroencephalogram (EEG) recordings, we exploited the trial-by-trial perceptual variability of incongruent audio-visual (AV) speech stimuli to identify the characteristics of the large-scale cortical network that facilitates multisensory perception during synchronous and asynchronous AV speech. We evaluated the spectral landscape of EEG signals during multisensory speech perception at varying AV lags. Functional connectivity dynamics for all sensor pairs was computed using the time-frequency global coherence, the vector sum of pairwise coherence changes over time. During synchronous AV speech, we observed enhanced global gamma-band coherence and decreased alpha and beta-band coherence underlying cross-modal (illusory) perception compared to unisensory perception around a temporal window of 300-600 ms following onset of stimuli. During asynchronous speech stimuli, a global broadband coherence was observed during cross-modal perception at earlier times along with pre-stimulus decreases of lower frequency power, e.g., alpha rhythms for positive AV lags and theta rhythms for negative AV lags. Thus, our

  6. Large Scale Functional Brain Networks Underlying Temporal Integration of Audio-Visual Speech Perception: An EEG Study

    Science.gov (United States)

    Kumar, G. Vinodh; Halder, Tamesh; Jaiswal, Amit K.; Mukherjee, Abhishek; Roy, Dipanjan; Banerjee, Arpan

    2016-01-01

    Observable lip movements of the speaker influence perception of auditory speech. A classical example of this influence is reported by listeners who perceive an illusory (cross-modal) speech sound (McGurk-effect) when presented with incongruent audio-visual (AV) speech stimuli. Recent neuroimaging studies of AV speech perception accentuate the role of frontal, parietal, and the integrative brain sites in the vicinity of the superior temporal sulcus (STS) for multisensory speech perception. However, if and how does the network across the whole brain participates during multisensory perception processing remains an open question. We posit that a large-scale functional connectivity among the neural population situated in distributed brain sites may provide valuable insights involved in processing and fusing of AV speech. Varying the psychophysical parameters in tandem with electroencephalogram (EEG) recordings, we exploited the trial-by-trial perceptual variability of incongruent audio-visual (AV) speech stimuli to identify the characteristics of the large-scale cortical network that facilitates multisensory perception during synchronous and asynchronous AV speech. We evaluated the spectral landscape of EEG signals during multisensory speech perception at varying AV lags. Functional connectivity dynamics for all sensor pairs was computed using the time-frequency global coherence, the vector sum of pairwise coherence changes over time. During synchronous AV speech, we observed enhanced global gamma-band coherence and decreased alpha and beta-band coherence underlying cross-modal (illusory) perception compared to unisensory perception around a temporal window of 300–600 ms following onset of stimuli. During asynchronous speech stimuli, a global broadband coherence was observed during cross-modal perception at earlier times along with pre-stimulus decreases of lower frequency power, e.g., alpha rhythms for positive AV lags and theta rhythms for negative AV lags. Thus

  7. Auditory display as a prosthetic hand sensory feedback for reaching and grasping tasks.

    Science.gov (United States)

    Gonzalez, Jose; Suzuki, Hiroyuki; Natsumi, Nakayama; Sekine, Masashi; Yu, Wenwei

    2012-01-01

    Upper limb amputees have to rely extensively on visual feedback in order to monitor and manipulate successfully their prosthetic device. This situation leads to high consciousness burden, which generates fatigue and frustration. Therefore, in order to enhance motor-sensory performance and awareness, an auditory display was used as a sensory feedback system for the prosthetic hand's spatio-temporal and force information in a complete reaching and grasping setting. The main objective of this study was to explore the effects of using the auditory display to monitor the prosthetic hand during a complete reaching and grasping motion. The results presented in this paper point out that the usage of an auditory display to monitor and control a robot hand improves the temporal and grasping performance greatly, while reducing mental effort and improving their confidence.

  8. 3D-reconstructions and virtual 4D-visualization to study metamorphic brain development in the sphinx moth Manduca sexta

    Directory of Open Access Journals (Sweden)

    Wolf Huetteroth

    2010-03-01

    Full Text Available During metamorphosis, the transition from the larva to the adult, the insect brain undergoes considerable remodeling: New neurons are integrated while larval neurons are remodeled or eliminated. One well acknowledged model to study metamorphic brain development is the sphinx moth Manduca sexta. To further understand mechanisms involved in the metamorphic transition of the brain we generated a 3D standard brain based on selected brain areas of adult females and 3D reconstructed the same areas during defined stages of pupal development. Selected brain areas include for example mushroom bodies, central complex, antennal- and optic lobes. With this approach we eventually want to quantify developmental changes in neuropilar architecture, but also quantify changes in the neuronal complement and monitor the development of selected neuronal populations. Furthermore, we used a modeling software (Cinema 4D to create a virtual 4D brain, morphing through its developmental stages. Thus the didactical advantages of 3D visualization are expanded to better comprehend complex processes of neuropil formation and remodeling during development. To obtain datasets of the M. sexta brain areas, we stained whole brains with an antiserum against the synaptic vesicle protein synapsin. Such labeled brains were then scanned with a confocal laser scanning microscope and selected neuropils were reconstructed with the 3D software AMIRA 4.1.

  9. Development of prosthetic arm with pneumatic prosthetic hand and tendon-driven wrist.

    Science.gov (United States)

    Takeda, Hiroyuki; Tsujiuchi, Nobutaka; Koizumi, Takayuki; Kan, Hiroto; Hirano, Masanori; Nakamura, Yoichiro

    2009-01-01

    Recently, various prosthetic arms have been developed, but few are both attractive and functional. Considering human coexistence, prosthetic arms must be both safe and flexible. In this research, we developed a novel prosthetic arm with a five-fingered prosthetic hand using our original pneumatic actuators and a slender tendon-driven wrist using a wire drive and two small motors. Because the prosthetic hand's driving source is comprised of small pneumatic actuators, the prosthetic hand is safe when it makes contact with people; it can also operate flexibly. In addition, the arm has a tendon-driven wrist to expand its motion space and to perform many operations. First, we explain the pneumatic hand's drive mechanism and its tendon-driven wrist. Next, we identify the characteristics of the hand and the wrist and construct a control system for this arm and verify its control performance.

  10. A survey of prosthetic eye wearers to investigate mucoid discharge

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    Pine K

    2012-05-01

    Full Text Available Keith Pine1, Brian Sloan2, Joanna Stewart3, Robert J Jacobs11Department of Optometry and Vision Science, 2Department of Ophthalmology, New Zealand National Eye Centre, 3Section of Epidemiology and Biostatistics, School of Population Health, University of Auckland, Auckland, New ZealandBackground: This study aimed to better understand the causes and treatments of mucoid discharge associated with prosthetic eye wear by reviewing the literature and surveying anophthalmic patients.Methods: An anonymous questionnaire was completed by 429 prosthetic eye wearers who used visual analog scales to self-measure their discharge experience for four discharge characteristics: frequency, color, volume, and viscosity. These characteristics were analyzed with age, ethnicity, years wearing a prosthesis, eye loss cause, removal and cleaning regimes, hand-washing behavior, age of current prosthesis, and professional repolishing regimes as explanatory variables. Eighteen ocularists’ Web sites containing comments on the cause and treatment of discharge were surveyed.Results: Associations were found between discharge frequency and cleaning regimes with more frequent cleaning accompanying more frequent discharge. Color was associated with years of wearing and age, with more years of wearing and older people having less colored discharge. Volume was associated with cleaning regimes with more frequent cleaners having more volume. Viscosity was associated with cleaning regimes and years of wearing with more frequent cleaning and shorter wearing time accompanying more viscous discharge. No associations were found between discharge characteristics and ethnicity, eye loss cause, hand washing, age of current prosthesis, or repolishing regimes. Forty-seven percent of ocularists’ Web sites advised that discharge was caused by surface deposits on the prosthesis, 29% by excessive handling of the prosthesis, and 24% by other causes.Conclusions: A standardized treatment

  11. Virtual brain mapping: Meta-analysis and visualization in functional neuroimaging

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup

    Results from functional neuroimaging such as positron emission tomography and functional magnetic resonance are often reported as sets of 3-dimensional coordinates in Talairach stereotactic space. By utilizing data collected in the BrainMap database and from our own small XML database we can...... data matrix. By conditioning on elements in the databases other than the coordinate data, e.g., anatomical labels associated with many coordinates we can make conditional novelty detection identifying outliers in the database that might be errorneous entries or seldom occuring patterns. In the Brain......Map database we found errors, e.g., stemming from confusion of centimeters and millimeters during entering and errors in the original article. Conditional probability density modeling also enables generation of probabilistic atlases and automatic probabilistic anatomical labeling of new coordinates...

  12. A Study for Visual Realism of Designed Pictures on Computer Screens by Investigation and Brain-Wave Analyses.

    Science.gov (United States)

    Wang, Lan-Ting; Lee, Kun-Chou

    2016-08-01

    In this article, the visual realism of designed pictures on computer screens is studied by investigation and brain-wave analyses. The practical electroencephalogram (EEG) measurement is always time-varying and fluctuating so that conventional statistical techniques are not adequate for analyses. This study proposes a new scheme based on "fingerprinting" to analyze the EEG. Fingerprinting is a technique of probabilistic pattern recognition used in electrical engineering, very like the identification of human fingerprinting in a criminal investigation. The goal of this study was to assess whether subjective preference for pictures could be manifested physiologically by EEG fingerprinting analyses. The most important advantage of the fingerprinting technique is that it does not require accurate measurement. Instead, it uses probabilistic classification. Participants' preference for pictures can be assessed using fingerprinting analyses of physiological EEG measurements.

  13. Single-trial detection of visual evoked potentials by common spatial patterns and wavelet filtering for brain-computer interface.

    Science.gov (United States)

    Tu, Yiheng; Huang, Gan; Hung, Yeung Sam; Hu, Li; Hu, Yong; Zhang, Zhiguo

    2013-01-01

    Event-related potentials (ERPs) are widely used in brain-computer interface (BCI) systems as input signals conveying a subject's intention. A fast and reliable single-trial ERP detection method can be used to develop a BCI system with both high speed and high accuracy. However, most of single-trial ERP detection methods are developed for offline EEG analysis and thus have a high computational complexity and need manual operations. Therefore, they are not applicable to practical BCI systems, which require a low-complexity and automatic ERP detection method. This work presents a joint spatial-time-frequency filter that combines common spatial patterns (CSP) and wavelet filtering (WF) for improving the signal-to-noise (SNR) of visual evoked potentials (VEP), which can lead to a single-trial ERP-based BCI.

  14. Dynamics of target and distractor processing in visual search: evidence from event-related brain potentials.

    Science.gov (United States)

    Hilimire, Matthew R; Mounts, Jeffrey R W; Parks, Nathan A; Corballis, Paul M

    2011-05-20

    When multiple objects are present in a visual scene, salient and behaviorally relevant objects are attentionally selected and receive enhanced processing at the expense of less salient or less relevant objects. Here we examined three lateralized components of the event-related potential (ERP) - the N2pc, Ptc, and SPCN - as indices of target and distractor processing in a visual search paradigm. Participants responded to the orientation of a target while ignoring an attentionally salient distractor and ERPs elicited by the target and the distractor were obtained. Results indicate that both the target and the distractor elicit an N2pc component which may index the initial attentional selection of both objects. In contrast, only the distractor elicited a significant Ptc, which may reflect the subsequent suppression of distracting or irrelevant information. Thus, the Ptc component appears to be similar to another ERP component - the Pd - which is also thought to reflect distractor suppression. Furthermore, only the target elicited an SPCN component which likely reflects the representation of the target in visual short term memory.

  15. Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain.

    Science.gov (United States)

    Bouchard, Jean-François; Casanova, Christian; Cécyre, Bruno; Redmond, William John

    2016-01-01

    Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system. Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function. In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing. The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far. It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells. The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.

  16. Investigating the role of combined acoustic-visual feedback in one-dimensional synchronous brain computer interfaces, a preliminary study

    Directory of Open Access Journals (Sweden)

    Gargiulo GD

    2012-09-01

    Full Text Available Gaetano D Gargiulo,1–3 Armin Mohamed,1 Alistair L McEwan,1 Paolo Bifulco,2 Mario Cesarelli,2 Craig T Jin,1 Mariano Ruffo,2 Jonathan Tapson,3 André van Schaik31School of Electrical and Information Engineering, The University of Sydney, New South Wales, Australia; 2Dipartimento di Ingegneria Elettronica e delle Telecomunicazioni "Federico II" University of Naples, Naples, Italy; 3BENS Laboratory, MARCS Institute, The University of Western Sydney, New South Wales, AustraliaAbstract: Feedback plays an important role when learning to use a brain computer interface (BCI, particularly in the case of synchronous feedback that relies on the interaction subject. In this preliminary study, we investigate the role of combined auditory-visual feedback during synchronous µ rhythm-based BCI sessions to help the subject to remain focused on the selected imaginary task. This new combined feedback, now integrated within the general purpose BCI2000 software, has been tested on eight untrained and three trained subjects during a monodimensional left-right control task. In order to reduce the setup burden and maximize subject comfort, an electroencephalographic device suitable for dry electrodes that required no skin preparation was used. Quality and index of improvement was evaluated based on a personal self-assessment questionnaire from each subject and quantitative data based on subject performance. Results for this preliminary study show that the combined feedback was well tolerated by the subjects and improved performance in 75% of the naïve subjects compared with visual feedback alone.Keywords: brain computer interface, dry electrodes, subject feedback

  17. [A wireless smart home system based on brain-computer interface of steady state visual evoked potential].

    Science.gov (United States)

    Zhao, Li; Xing, Xiao; Guo, Xuhong; Liu, Zehua; He, Yang

    2014-10-01

    Brain-computer interface (BCI) system is a system that achieves communication and control among humans and computers and other electronic equipment with the electroencephalogram (EEG) signals. This paper describes the working theory of the wireless smart home system based on the BCI technology. We started to get the steady-state visual evoked potential (SSVEP) using the single chip microcomputer and the visual stimulation which composed by LED lamp to stimulate human eyes. Then, through building the power spectral transformation on the LabVIEW platform, we processed timely those EEG signals under different frequency stimulation so as to transfer them to different instructions. Those instructions could be received by the wireless transceiver equipment to control the household appliances and to achieve the intelligent control towards the specified devices. The experimental results showed that the correct rate for the 10 subjects reached 100%, and the control time of average single device was 4 seconds, thus this design could totally achieve the original purpose of smart home system.

  18. Investigating the role of combined acoustic-visual feedback in one-dimensional synchronous brain computer interfaces, a preliminary study

    Science.gov (United States)

    Gargiulo, Gaetano D; Mohamed, Armin; McEwan, Alistair L; Bifulco, Paolo; Cesarelli, Mario; Jin, Craig T; Ruffo, Mariano; Tapson, Jonathan; van Schaik, André

    2012-01-01

    Feedback plays an important role when learning to use a brain computer interface (BCI), particularly in the case of synchronous feedback that relies on the interaction subject. In this preliminary study, we investigate the role of combined auditory-visual feedback during synchronous μ rhythm-based BCI sessions to help the subject to remain focused on the selected imaginary task. This new combined feedback, now integrated within the general purpose BCI2000 software, has been tested on eight untrained and three trained subjects during a monodimensional left-right control task. In order to reduce the setup burden and maximize subject comfort, an electroencephalographic device suitable for dry electrodes that required no skin preparation was used. Quality and index of improvement was evaluated based on a personal self-assessment questionnaire from each subject and quantitative data based on subject performance. Results for this preliminary study show that the combined feedback was well tolerated by the subjects and improved performance in 75% of the naïve subjects compared with visual feedback alone. PMID:23152713

  19. Reliability-based automatic repeat request for short code modulation visual evoked potentials in brain computer interfaces.

    Science.gov (United States)

    Sato, Jun-Ichi; Washizawa, Yoshikazu

    2015-08-01

    We propose two methods to improve code modulation visual evoked potential brain computer interfaces (cVEP BCIs). Most of BCIs average brain signals from several trials in order to improve the classification performance. The number of averaging defines the trade-off between input speed and accuracy, and the optimal averaging number depends on individual, signal acquisition system, and so forth. Firstly, we propose a novel dynamic method to estimate the averaging number for cVEP BCIs. The proposed method is based on the automatic repeat request (ARQ) that is used in communication systems. The existing cVEP BCIs employ rather longer code, such as 63-bit M-sequence. The code length also defines the trade-off between input speed and accuracy. Since the reliability of the proposed BCI can be controlled by the proposed ARQ method, we introduce shorter codes, 32-bit M-sequence and the Kasami-sequence. Thanks to combine the dynamic averaging number estimation method and the shorter codes, the proposed system exhibited higher information transfer rate compared to existing cVEP BCIs.

  20. Cytosolic NADH-NAD+ Redox Visualized in Brain Slices by Two-Photon Fluorescence Lifetime Biosensor Imaging

    Science.gov (United States)

    Mongeon, Rebecca; Venkatachalam, Veena

    2016-01-01

    Abstract Aim: Cytosolic NADH-NAD+ redox state is central to cellular metabolism and a valuable indicator of glucose and lactate metabolism in living cells. Here we sought to quantitatively determine NADH-NAD+ redox in live cells and brain tissue using a fluorescence lifetime imaging of the genetically-encoded single-fluorophore biosensor Peredox. Results: We show that Peredox exhibits a substantial change in its fluorescence lifetime over its sensing range of NADH-NAD+ ratio. This allows changes in cytosolic NADH redox to be visualized in living cells using a two-photon scanning microscope with fluorescence lifetime imaging capabilities (2p-FLIM), using time-correlated single photon counting. Innovation: Because the lifetime readout is absolutely calibrated (in nanoseconds) and is independent of sensor concentration, we demonstrate that quantitative assessment of NADH redox is possible using a single fluorophore biosensor. Conclusion: Imaging of the sensor in mouse hippocampal brain slices reveals that astrocytes are typically much more reduced (with higher NADH:NAD+ ratio) than neurons under basal conditions, consistent with the hypothesis that astrocytes are more glycolytic than neurons. Antioxid. Redox Signal. 25, 553–563. PMID:26857245

  1. Committing to Memory: Memory Prosthetics Show Promise in Helping Those with Neurodegenerative Disorders.

    Science.gov (United States)

    Solis, Michele

    2017-01-01

    Cell phone chimes, sticky notes, even the proverbial string around a finger-these timehonored external cues help guard against our inevitable memory lapses. But some internal help to the brain itself may be on the way in the form of what's being called memory prosthetics. Once considered to be on the fringes of neuroscience, the idea of adding hardware to the brain to help with memory has gathered steam. In 2014, the U.S. Defense Advanced Research Projects Agency (DARPA) made a US$30 million investment in memory prosthetic research as part of the Obama administration's Brain Research through Advancing Innovative Neurotechnologies initiative. In August 2016, Kernel, a startup based in Los Angeles, California, announced its goal to develop a clinical memory device for those debilitated by neurodegenerative disorders such as Alzheimer's disease.

  2. Effect of visual experience on structural organization of the human brain: A voxel based morphometric study using DARTEL

    Energy Technology Data Exchange (ETDEWEB)

    Modi, Shilpi, E-mail: modi_shilpi@yahoo.co.in [NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (DRDO), Lucknow Road, Timarpur, Delhi (India); Bhattacharya, Manisha, E-mail: manishab10@gmail.com [NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (DRDO), Lucknow Road, Timarpur, Delhi (India); Singh, Namita, E-mail: namita23m@gmail.com [NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (DRDO), Lucknow Road, Timarpur, Delhi (India); Tripathi, Rajendra Prasad, E-mail: director@inmas.drdo.in [NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (DRDO), Lucknow Road, Timarpur, Delhi (India); Khushu, Subash, E-mail: skhushu@yahoo.com [NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences (DRDO), Lucknow Road, Timarpur, Delhi (India)

    2012-10-15

    Objective: To investigate structural reorganization in the brain with differential visual experience using Voxel-Based Morphometry with Diffeomorphic Anatomic Registration Through Exponentiated Lie algebra algorithm (DARTEL) approach. Materials and methods: High resolution structural MR images were taken in fifteen normal sighted healthy controls, thirteen totally blind subjects and six partial blind subjects. The analysis was carried out using SPM8 software on MATLAB 7.6.0 platform. Results: VBM study revealed gray matter volume atrophy in the cerebellum and left inferior parietal cortex in total blind subjects and in left inferior parietal cortex, right caudate nucleus, and left primary visual cortex in partial blind subjects as compared to controls. White matter volume loss was found in calcarine gyrus in total blind subjects and Thlamus-somatosensory region in partially blind subjects as compared to controls. Besides, an increase in Gray Matter volume was also found in left middle occipital and middle frontal gyrus and right entorhinal cortex, and an increase in White Matter volume was found in superior frontal gyrus, left middle temporal gyrus and right Heschl's gyrus in totally blind subjects as compared to controls. Comparison between total and partial blind subjects revealed a greater Gray Matter volume in left cerebellum of partial blinds and left Brodmann area 18 of total blind subjects. Conclusion: Results suggest that, loss of vision at an early age can induce significant structural reorganization on account of the loss of visual input. These plastic changes are different in early onset of total blindness as compared to partial blindness.

  3. Computed Tomography of Prosthetic Heart Valves

    NARCIS (Netherlands)

    Habets, J.

    2012-01-01

    Prosthetic heart valve (PHV) dysfunction is an infrequent but potentially life-threatening disease with a heterogeneous clinical presentation. Patients with PHV dysfunction clinically can present with symptoms of congestive heart failure (dyspnea, fatigue, edema), fever, angina pectoris, dizziness d

  4. Advanced prosthetic techniques for below knee amputations.

    Science.gov (United States)

    Staats, T B

    1985-02-01

    Recent advances in the evaluation of the amputation stump, the materials that are available for prosthetic application, techniques of improving socket fit, and prosthetic finishings promise to dramatically improve amputee function. Precision casting techniques for providing optimal fit of the amputation stump using materials such as alginate are described. The advantages of transparent check sockets for fitting the complicated amputation stump are described. Advances in research that promise to provide more functional prosthetic feet and faster and more reliable socket molding are the use of CAD-CAM (computer aided design-computer aided manufacturing) and the use of gait analysis techniques to aid in the alignment of the prosthesis after socket fitting. Finishing techniques to provide a more natural appearing prosthesis are described. These advances will gradually spread to the entire prosthetic profession.

  5. DME Prosthetics Orthotics, and Supplies Fee Schedule

    Data.gov (United States)

    U.S. Department of Health & Human Services — Durable Medical Equipment, Prosthetics-Orthotics, and Supplies Fee Schedule. The list contains the fee schedule amounts, floors, and ceilings for all procedure codes...

  6. Creative mechanism design for a prosthetic hand.

    Science.gov (United States)

    Chang, Wen-Tung; Tseng, Ching-Huan; Wu, Long-Long

    2004-01-01

    In this paper, an auxiliary methodology called the creative mechanism design is introduced into the innovation of gripping devices for prosthetic hands. This methodology is a systematic approach based on modification of existing devices for the generation of all possible topological structures of mechanisms and mechanical devices. An existing gripping device (Teh Lin ATG-5F prosthetic hand) constructed by a planar six-bar linkage with one degree of freedom is dealt with by using this methodology. Through the processes of generalization, number synthesis, specialization and particularization for the existing design, five new mechanisms are created in this study to apply to anthropomorphic prosthetic hands. The results show that the methodology for creative mechanism design is a powerful tool for creating new categories of mechanisms to avoid existing designs that have patent protection and can help designers in the conceptual phase. Also, this methodology is validated as a useful way to improve prosthetic hands for amputees.

  7. Real-time fMRI brain-computer interface: Development of a "motivational feedback" subsystem for the regulation of visual cue reactivity

    Directory of Open Access Journals (Sweden)

    Moses O. Sokunbi

    2014-11-01

    Full Text Available Here we present a novel neurofeedback subsystem for the presentation of motivationally relevant visual feedback during the self-regulation of functional brain activation. Our motivational neurofeedback approach uses functional magnetic resonance imaging (fMRI signals elicited by visual cues (pictures and related to motivational processes such as craving or hunger. The visual feedback subsystem provides simultaneous feedback through these images as their size corresponds to the magnitude of fMRI signal change from a target brain area. During self-regulation of cue-evoked brain responses, decreases and increases in picture size thus provide real motivational consequences in terms of cue approach versus cue avoidance, which increases face validity of the approach in applied settings. Further, the outlined approach comprises of neurofeedback (regulation and mirror runs that allow to control for non-specific and task-unrelated effects, such as habituation or neural adaptation. The approach was implemented in the Python programming language. Pilot data from 10 volunteers showed that participants were able to successfully down-regulate individually defined target areas, demonstrating feasibility of the approach. The newly developed visual feedback subsystem can be integrated into protocols for imaging-based brain-computer interfaces (BCI and may facilitate neurofeedback research and applications into healthy and dysfunctional motivational processes, such food craving or addiction.

  8. Surgical and Prosthetic Rehabilitation of Combination Syndrome

    Directory of Open Access Journals (Sweden)

    Paolo Carlino

    2014-01-01

    Full Text Available The aim of this report is to analyze the clinical symptoms, ethologic factors, and prosthetic rehabilitation in a case of Combination Syndrome (CS. The treatment of CS can be conventional or surgical, with or without the bone reconstruction of maxilla. The correct prosthetic treatment helps this kind of patients to restore the physiologic occlusion plane to allow a correct masticatory and aesthetic function. Management of this kind of patients can be a challenge for a dental practitioner.

  9. Advances in lower-limb prosthetic technology.

    Science.gov (United States)

    Laferrier, Justin Z; Gailey, Robert

    2010-02-01

    The boundaries once faced by individuals with amputations are quickly being overcome through biotechnology. Although there are currently no prosthetics capable of replicating anatomic function, there have been radical advancements in prosthetic technology, medical science, and rehabilitation in the past 30 years, vastly improving functional mobility and quality of life for individuals with lower-limb amputations. What once seemed impossible is rapidly becoming reality. The future seems limitless, and the replication of anatomic function now seems possible.

  10. Tenecteplase in prosthetic mitral valve thrombosis

    OpenAIRE

    2010-01-01

    In the few reported cases of prosthetic mitral valve thrombosis, where surgical intervention was considered as high risk, fibrinolytic therapy had proved life saving. The authors present clinical, laboratory, and imaging data from such a patient, with prosthetic mitral valve thrombosis and its successful management with tenecteplase. The use of tenecteplase as a viable fibrinolytic agent for the first time was justified, due to the lack of immunogenicity concerns compared to streptokinase.

  11. Tenecteplase in prosthetic mitral valve thrombosis.

    Science.gov (United States)

    Ayyub Ghori, Masood; Bakir, Sherif; Ellahham, Samer; Al Nassir, Adnan; Al Zubaidi, Abdulmajeed; Augustin, Norbert; Abdelaziz, Moataz Ayman; Turrin, Nicolas Patrick; Al Mahmeed, Wael Abdulrahman

    2011-04-01

    In the few reported cases of prosthetic mitral valve thrombosis, where surgical intervention was considered as high risk, fibrinolytic therapy had proved life saving. The authors present clinical, laboratory, and imaging data from such a patient, with prosthetic mitral valve thrombosis and its successful management with tenecteplase. The use of tenecteplase as a viable fibrinolytic agent for the first time was justified, due to the lack of immunogenicity concerns compared to streptokinase.

  12. Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Seok Kyun; Kim, Gwang Won; Kang, Heoung Keun; Jeong, Gwang Woo [Chonnam National University, Gwangju (Korea, Republic of); Yang, Jong Chul [Chonbuk National University Medical School, Jeonju (Korea, Republic of); Kim, Seok Kwun [Dong-A University College of Medicine, Busan (Korea, Republic of)

    2012-06-15

    This study used functional magnetic resonance imaging (fMRI) to contrast the differential brain activation patterns in response to visual stimulation with both male and female erotic nude pictures in male-to-female (MTF) transsexuals who underwent a sex reassignment surgery. A total of nine healthy MTF transsexuals after a sex reassignment surgery underwent fMRI on a 3.0 Tesla MR Scanner. The brain activation patterns were induced by visual stimulation with both male and female erotic nude pictures. The sex hormone levels of the postoperative MTF transsexuals were in the normal range of healthy heterosexual females. The brain areas, which were activated by viewing male nude pictures when compared with viewing female nude pictures, included predominantly the cerebellum, hippocampus, putamen, anterior cingulate gyrus, head of caudate nucleus, amygdala, midbrain, thalamus, insula, and body of caudate nucleus. On the other hand, brain activation induced by viewing female nude pictures was predominantly observed in the hypothalamus and the septal area. Our findings suggest that distinct brain activation patterns associated with visual sexual arousal in postoperative MTF transsexuals reflect their sexual orientation to males.

  13. Rechargeable wireless EMG sensor for prosthetic control.

    Science.gov (United States)

    Lichter, P A; Lange, E H; Riehle, T H; Anderson, S M; Hedin, D S

    2010-01-01

    Surface electrodes in modern myoelectric prosthetics are often embedded in the prosthesis socket and make contact with the skin. These electrodes detect and amplify muscle action potentials from voluntary contractions of the muscle in the residual limb and are used to control the prosthetic's movement and function. There are a number of performance-related deficiencies associated with external electrodes including the maintenance of sufficient electromyogram (EMG) signal amplitude, extraneous noise acquisition, and proper electrode interface maintenance that are expected to be improved or eliminated using the proposed implanted sensors. This research seeks to investigate the design components for replacing external electrodes with fully-implantable myoelectric sensors that include a wireless interface to the prosthetic limbs. This implanted technology will allow prosthetic limb manufacturers to provide products with increased performance, capability, and patient-comfort. The EMG signals from the intramuscular recording electrode are amplified and wirelessly transmitted to a receiver in the prosthetic limb. Power to the implant is maintained using a rechargeable battery and an inductive energy transfer link from the prosthetic. A full experimental system was developed to demonstrate that a wireless biopotential sensor can be designed that meets the requirements of size, power, and performance for implantation.

  14. Modeling Visual Information Processing in Brain: A Computer Vision Point of View and Approach

    CERN Document Server

    Diamant, Emanuel

    2007-01-01

    We live in the Information Age, and information has become a critically important component of our life. The success of the Internet made huge amounts of it easily available and accessible to everyone. To keep the flow of this information manageable, means for its faultless circulation and effective handling have become urgently required. Considerable research efforts are dedicated today to address this necessity, but they are seriously hampered by the lack of a common agreement about "What is information?" In particular, what is "visual information" - human's primary input from the surrounding world. The problem is further aggravated by a long-lasting stance borrowed from the biological vision research that assumes human-like information processing as an enigmatic mix of perceptual and cognitive vision faculties. I am trying to find a remedy for this bizarre situation. Relying on a new definition of "information", which can be derived from Kolmogorov's compexity theory and Chaitin's notion of algorithmic inf...

  15. Assessment of sexual orientation using the hemodynamic brain response to visual sexual stimuli

    DEFF Research Database (Denmark)

    Ponseti, Jorge; Granert, Oliver; Jansen, Olav

    2009-01-01

    INTRODUCTION: The assessment of sexual orientation is of importance to the diagnosis and treatment of sex offenders and paraphilic disorders. Phallometry is considered gold standard in objectifying sexual orientation, yet this measurement has been criticized because of its intrusiveness and limited...... in a nonclinical sample of 12 heterosexual men and 14 homosexual men. During fMRI, participants were briefly exposed to pictures of same-sex and opposite-sex genitals. Data analysis involved four steps: (i) differences in the BOLD response to female and male sexual stimuli were calculated for each subject; (ii......) these contrast images were entered into a group analysis to calculate whole-brain difference maps between homosexual and heterosexual participants; (iii) a single expression value was computed for each subject expressing its correspondence to the group result; and (iv) based on these expression values, Fisher...

  16. A social Bayesian brain: How social knowledge can shape visual perception.

    Science.gov (United States)

    Otten, Marte; Seth, Anil K; Pinto, Yair

    2017-03-01

    A growing body of research suggests that social contextual factors such as desires and goals, affective states and stereotypes can shape early perceptual processes. We suggest that a generative Bayesian approach towards perception provides a powerful theoretical framework to accommodate how such high-level social factors can influence low-level perceptual processes in their earliest stages. We review experimental findings that show how social factors shape the perception and evaluation of people, behaviour, and socially relevant objects or information. Subsequently, we summarize the generative view of perception within the 'Bayesian brain', and show how such a framework can account for the pervasive effects of top-down social knowledge on social cognition. Finally, we sketch the theoretical and experimental implications of social predictive perception, indicating new directions for research on the effects and neurocognitive underpinnings of social cognition.

  17. Cholinesterase inhibition modulates visual and attentional brain responses in Alzheimer's disease and health.

    Science.gov (United States)

    Bentley, Paul; Driver, Jon; Dolan, Ray J

    2008-02-01

    Visuo-attentional deficits occur early in Alzheimer's disease (AD) and are considered more responsive to pro-cholinergic therapy than characteristic memory disturbances. We hypothesised that neural responses in AD during visuo-attentional processing would be impaired relative to controls, yet partially susceptible to improvement with the cholinesterase inhibitor physostigmine. We studied 16 mild AD patients and 17 age-matched healthy controls, using fMRI-scanning to enable within-subject placebo-controlled comparisons of effects of physostigmine on stimulus- and attention- related brain activations, plus between-group comparisons for these. Subjects viewed face or building stimuli while performing a shallow judgement (colour of image) or a deep judgement (young/old age of depicted face or building). Behaviourally, AD subjects performed slower than controls in both tasks, while physostigmine benefited the patients for the more demanding age-judgement task. Stimulus-selective (face minus building, and vice versa) BOLD signals in precuneus and posterior parahippocampal cortex were attenuated in patients relative to controls, but increased following physostigmine. By contrast, face-selective responses in fusiform cortex were not impaired in AD and showed decreases following physostigmine for both groups. Task-dependent responses in right parietal and prefrontal cortices were diminished in AD but improved following physostigmine. A similar pattern of group and treatment effects was observed in two extrastriate cortical regions that showed physostigmine-induced enhancement of stimulus-selectivity for the deep versus shallow task. Finally, for the healthy group, physostigmine decreased stimulus and task-dependent effects, partly due to an exaggeration of selectivity during the shallow relative to deep task. The differences in brain activations between groups and treatments were not attributable merely to performance (reaction time) differences. Our results demonstrate

  18. Parietal neural prosthetic control of a computer cursor in a graphical-user-interface task

    Science.gov (United States)

    Revechkis, Boris; Aflalo, Tyson NS; Kellis, Spencer; Pouratian, Nader; Andersen, Richard A.

    2014-12-01

    Objective. To date, the majority of Brain-Machine Interfaces have been used to perform simple tasks with sequences of individual targets in otherwise blank environments. In this study we developed a more practical and clinically relevant task that approximated modern computers and graphical user interfaces (GUIs). This task could be problematic given the known sensitivity of areas typically used for BMIs to visual stimuli, eye movements, decision-making, and attentional control. Consequently, we sought to assess the effect of a complex, GUI-like task on the quality of neural decoding. Approach. A male rhesus macaque monkey was implanted with two 96-channel electrode arrays in area 5d of the superior parietal lobule. The animal was trained to perform a GUI-like ‘Face in a Crowd’ task on a computer screen that required selecting one cued, icon-like, face image from a group of alternatives (the ‘Crowd’) using a neurally controlled cursor. We assessed whether the crowd affected decodes of intended cursor movements by comparing it to a ‘Crowd Off’ condition in which only the matching target appeared without alternatives. We also examined if training a neural decoder with the Crowd On rather than Off had any effect on subsequent decode quality. Main results. Despite the additional demands of working with the Crowd On, the animal was able to robustly perform the task under Brain Control. The presence of the crowd did not itself affect decode quality. Training the decoder with the Crowd On relative to Off had no negative influence on subsequent decoding performance. Additionally, the subject was able to gaze around freely without influencing cursor position. Significance. Our results demonstrate that area 5d recordings can be used for decoding in a complex, GUI-like task with free gaze. Thus, this area is a promising source of signals for neural prosthetics that utilize computing devices with GUI interfaces, e.g. personal computers, mobile devices, and tablet

  19. Cetacean Swimming with Prosthetic Limbs

    Science.gov (United States)

    Bode-Oke, Ayodeji; Ren, Yan; Dong, Haibo; Fish, Frank

    2016-11-01

    During entanglement in fishing gear, dolphins can suffer abrasions and amputations of flukes and fins. As a result, if the dolphin survives the ordeal, swimming performance is altered. Current rehabilitation technques is the use of prosthesis to regain swimming ability. In this work, analyses are focused on two dolphins with locomotive impairment; Winter (currently living in Clearwater Marine Aquarium in Florida) and Fuji (lived in Okinawa Churaumi Aquarium in Japan). Fuji lost about 75% of its fluke surface to necrosis (death of cells) and Winter lost its tail due to amputation. Both dolphins are aided by prosthetic tails that mimic the shape of a real dolphin tail. Using 3D surface reconstruction techniques and a high fidelity Computational Fluid Dynamics (CFD) flow solver, we were able to elucidate the kinematics and hydrodynamics and fluke deformation of these swimmers to clarify the effectiveness of prostheses in helping the dolphins regain their swimming ability. Associated with the performance, we identified distinct features in the wake structures that can explain this gap in the performance compared to a healthy dolphin. This work was supported by ONR MURI Grant Number N00014-14-1-0533.

  20. Functional clustering drives encoding improvement in a developing brain network during awake visual learning.

    Directory of Open Access Journals (Sweden)

    Kaspar Podgorski

    2012-01-01

    Full Text Available Sensory experience drives dramatic structural and functional plasticity in developing neurons. However, for single-neuron plasticity to optimally improve whole-network encoding of sensory information, changes must be coordinated between neurons to ensure a full range of stimuli is efficiently represented. Using two-photon calcium imaging to monitor evoked activity in over 100 neurons simultaneously, we investigate network-level changes in the developing Xenopus laevis tectum during visual training with motion stimuli. Training causes stimulus-specific changes in neuronal responses and interactions, resulting in improved population encoding. This plasticity is spatially structured, increasing tuning curve similarity and interactions among nearby neurons, and decreasing interactions among distant neurons. Training does not improve encoding by single clusters of similarly responding neurons, but improves encoding across clusters, indicating coordinated plasticity across the network. NMDA receptor blockade prevents coordinated plasticity, reduces clustering, and abolishes whole-network encoding improvement. We conclude that NMDA receptors support experience-dependent network self-organization, allowing efficient population coding of a diverse range of stimuli.

  1. Brain potentials reflect access to visual and emotional memories for faces.

    Science.gov (United States)

    Bobes, Maria A; Quiñonez, Ileana; Perez, Jhoanna; Leon, Inmaculada; Valdés-Sosa, Mitchell

    2007-05-01

    Familiar faces convey different types of information, unlocking memories related to social-emotional significance. Here, the availability over time of different types of memory was evaluated using the time-course of P3 event related potentials. Two oddball paradigms were employed, both using unfamiliar faces as standards. The infrequent targets were, respectively, artificially-learned faces (devoid of social-emotional content) and faces of acquaintances. Although in both tasks targets were detected accurately, the corresponding time-course and scalp distribution of the P3 responses differed. Artificially-learned and acquaintance faces both elicited a P3b, maximal over centro-parietal sites, and a latency of 500ms. Faces of acquaintances elicited an additional component, an early P3 maximal over frontal sites: with a latency of 350ms. This suggests that visual familiarity can only trigger the overt recognition processes leading to the slower P3b, whereas emotional-social information can also elicit fast and automatic assessments (indexed by the frontal-P3) crucial for successful social interactions.

  2. Correlation mapping method of OCT for visualization blood vessels in brain

    Science.gov (United States)

    Izotova, O. A.; Kalyanov, A. L.; Lychagov, V. V.; Semyachkina-Glushkovskaya, O. V.

    2013-11-01

    The burning issue in modern medicine is the diagnosis and treatment of various life-threatening diseases, in particular the diseases of brain. One of them is intracranial hemorrhage (ICH). It occurs especially among newborn babies and is hard-diagnosed. In order to understand the nature of the ICH, the microcirculation of blood, which serves key functions within the body, is analyzed. On this basis a series of experiments was done, in the results of which it was showed, that latent stage of ICH is characterized by decrease of venous blood outflow and the loss of sensitivity of sagittal vein to vasoconstrictor effect of adrenaline. So, stress-related changes of the cerebral venous blood flow (CVBF) can be the source of this disease. In this paper registration CVBF was made with the help of commercially available Thorlabs Swept Source OCT System, using the correlation mapping method. In this method values of correlation coefficient of several images are analyzed. In the result of the algorithm the correlation map was obtained. By the resulting map the diameter of vessels was calculated, which is necessary for examination of effects of adrenalin to the vessels and identification symptoms of ICH.

  3. Sub-Chronic Neuropathological and Biochemical Changes in Mouse Visual System after Repetitive Mild Traumatic Brain Injury.

    Directory of Open Access Journals (Sweden)

    Radouil Tzekov

    Full Text Available Repetitive mild traumatic brain injury (r-mTBI results in neuropathological and biochemical consequences in the human visual system. Using a recently developed mouse model of r-mTBI, with control mice receiving repetitive anesthesia alone (r-sham we assessed the effects on the retina and optic nerve using histology, immunohistochemistry, proteomic and lipidomic analyses at 3 weeks post injury. Retina tissue was used to determine retinal ganglion cell (RGC number, while optic nerve tissue was examined for cellularity, myelin content, protein and lipid changes. Increased cellularity and areas of demyelination were clearly detectable in optic nerves in r-mTBI, but not in r-sham. These changes were accompanied by a ~25% decrease in the total number of Brn3a-positive RGCs. Proteomic analysis of the optic nerves demonstrated various changes consistent with a negative effect of r-mTBI on major cellular processes like depolymerization of microtubules, disassembly of filaments and loss of neurons, manifested by decrease of several proteins, including neurofilaments (NEFH, NEFM, NEFL, tubulin (TUBB2A, TUBA4A, microtubule-associated proteins (MAP1A, MAP1B, collagen (COL6A1, COL6A3 and increased expression of other proteins, including heat shock proteins (HSP90B1, HSPB1, APOE and cathepsin D. Lipidomic analysis showed quantitative changes in a number of phospholipid species, including a significant increase in the total amount of lysophosphatidylcholine (LPC, including the molecular species 16:0, a known demyelinating agent. The overall amount of some ether phospholipids, like ether LPC, ether phosphatidylcholine and ether lysophosphatidylethanolamine were also increased, while the majority of individual molecular species of ester phospholipids, like phosphatidylcholine and phosphatidylethanolamine, were decreased. Results from the biochemical analysis correlate well with changes detected by histological and immunohistochemical methods and indicate the

  4. Sub-Chronic Neuropathological and Biochemical Changes in Mouse Visual System after Repetitive Mild Traumatic Brain Injury.

    Science.gov (United States)

    Tzekov, Radouil; Dawson, Clint; Orlando, Megan; Mouzon, Benoit; Reed, Jon; Evans, James; Crynen, Gogce; Mullan, Michael; Crawford, Fiona

    2016-01-01

    Repetitive mild traumatic brain injury (r-mTBI) results in neuropathological and biochemical consequences in the human visual system. Using a recently developed mouse model of r-mTBI, with control mice receiving repetitive anesthesia alone (r-sham) we assessed the effects on the retina and optic nerve using histology, immunohistochemistry, proteomic and lipidomic analyses at 3 weeks post injury. Retina tissue was used to determine retinal ganglion cell (RGC) number, while optic nerve tissue was examined for cellularity, myelin content, protein and lipid changes. Increased cellularity and areas of demyelination were clearly detectable in optic nerves in r-mTBI, but not in r-sham. These changes were accompanied by a ~25% decrease in the total number of Brn3a-positive RGCs. Proteomic analysis of the optic nerves demonstrated various changes consistent with a negative effect of r-mTBI on major cellular processes like depolymerization of microtubules, disassembly of filaments and loss of neurons, manifested by decrease of several proteins, including neurofilaments (NEFH, NEFM, NEFL), tubulin (TUBB2A, TUBA4A), microtubule-associated proteins (MAP1A, MAP1B), collagen (COL6A1, COL6A3) and increased expression of other proteins, including heat shock proteins (HSP90B1, HSPB1), APOE and cathepsin D. Lipidomic analysis showed quantitative changes in a number of phospholipid species, including a significant increase in the total amount of lysophosphatidylcholine (LPC), including the molecular species 16:0, a known demyelinating agent. The overall amount of some ether phospholipids, like ether LPC, ether phosphatidylcholine and ether lysophosphatidylethanolamine were also increased, while the majority of individual molecular species of ester phospholipids, like phosphatidylcholine and phosphatidylethanolamine, were decreased. Results from the biochemical analysis correlate well with changes detected by histological and immunohistochemical methods and indicate the involvement of

  5. High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xu, Guang-Hua [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710054 (China)

    2015-03-10

    This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n{sup n} with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method.

  6. How visual illusions illuminate complementary brain processes: illusory depth from brightness and apparent motion of illusory contours.

    Science.gov (United States)

    Grossberg, Stephen

    2014-01-01

    Neural models of perception clarify how visual illusions arise from adaptive neural processes. Illusions also provide important insights into how adaptive neural processes work. This article focuses on two illusions that illustrate a fundamental property of global brain organization; namely, that advanced brains are organized into parallel cortical processing streams with computationally complementary properties. That is, in order to process certain combinations of properties, each cortical stream cannot process complementary properties. Interactions between these streams, across multiple processing stages, overcome their complementary deficiencies to compute effective representations of the world, and to thereby achieve the property of complementary consistency. The two illusions concern how illusory depth can vary with brightness, and how apparent motion of illusory contours can occur. Illusory depth from brightness arises from the complementary properties of boundary and surface processes, notably boundary completion and surface-filling in, within the parvocellular form processing cortical stream. This illusion depends upon how surface contour signals from the V2 thin stripes to the V2 interstripes ensure complementary consistency of a unified boundary/surface percept. Apparent motion of illusory contours arises from the complementary properties of form and motion processes across the parvocellular and magnocellular cortical processing streams. This illusion depends upon how illusory contours help to complete boundary representations for object recognition, how apparent motion signals can help to form continuous trajectories for target tracking and prediction, and how formotion interactions from V2-to-MT enable completed object representations to be continuously tracked even when they move behind intermittently occluding objects through time.

  7. Classifying prosthetic use via accelerometry in persons with transtibial amputations

    Directory of Open Access Journals (Sweden)

    Morgan T. Redfield, MSEE

    2013-12-01

    Full Text Available Knowledge of how persons with amputation use their prostheses and how this use changes over time may facilitate effective rehabilitation practices and enhance understanding of prosthesis functionality. Perpetual monitoring and classification of prosthesis use may also increase the health and quality of life for prosthetic users. Existing monitoring and classification systems are often limited in that they require the subject to manipulate the sensor (e.g., attach, remove, or reset a sensor, record data over relatively short time periods, and/or classify a limited number of activities and body postures of interest. In this study, a commercially available three-axis accelerometer (ActiLife ActiGraph GT3X+ was used to characterize the activities and body postures of individuals with transtibial amputation. Accelerometers were mounted on prosthetic pylons of 10 persons with transtibial amputation as they performed a preset routine of actions. Accelerometer data was postprocessed using a binary decision tree to identify when the prosthesis was being worn and to classify periods of use as movement (i.e., leg motion such as walking or stair climbing, standing (i.e., standing upright with limited leg motion, or sitting (i.e., seated with limited leg motion. Classifications were compared to visual observation by study researchers. The classifier achieved a mean +/– standard deviation accuracy of 96.6% +/– 3.0%.

  8. Classifying prosthetic use via accelerometry in persons with transtibial amputations.

    Science.gov (United States)

    Redfield, Morgan T; Cagle, John C; Hafner, Brian J; Sanders, Joan E

    2013-01-01

    Knowledge of how persons with amputation use their prostheses and how this use changes over time may facilitate effective rehabilitation practices and enhance understanding of prosthesis functionality. Perpetual monitoring and classification of prosthesis use may also increase the health and quality of life for prosthetic users. Existing monitoring and classification systems are often limited in that they require the subject to manipulate the sensor (e.g., attach, remove, or reset a sensor), record data over relatively short time periods, and/or classify a limited number of activities and body postures of interest. In this study, a commercially available three-axis accelerometer (ActiLife ActiGraph GT3X+) was used to characterize the activities and body postures of individuals with transtibial amputation. Accelerometers were mounted on prosthetic pylons of 10 persons with transtibial amputation as they performed a preset routine of actions. Accelerometer data was postprocessed using a binary decision tree to identify when the prosthesis was being worn and to classify periods of use as movement (i.e., leg motion such as walking or stair climbing), standing (i.e., standing upright with limited leg motion), or sitting (i.e., seated with limited leg motion). Classifications were compared to visual observation by study researchers. The classifier achieved a mean +/- standard deviation accuracy of 96.6% +/- 3.0%.

  9. Adaptive prosthetics for the lower extremity.

    Science.gov (United States)

    Carroll, K

    2001-06-01

    The potential for lifestyle recovery is tremendous for most lower extremity amputees. The amazing and ever-expanding array of adaptive prosthetics can help make the devastating loss of amputation more bearable for patients, their families, and their health care team. The new amputee, in a state of shock and grief, does not know what his or her prosthetic options are. It is crucial that the surgeon is knowledgeable about what the patient can have and what the patient needs to ask for. Dana Bowman stated: Ideally, the new amputee should say to their doctor, "I'd like my leg to be lightweight, flexible, durable, comfortable. I want to do sports or I want to ride bikes with my kids." Whatever it is they like to do. I was told I would never be able to wear two dynamic feet and that my sky diving days were over. I said, "Well how do you know? Can't I try?" It took years to find out what I could have and then to find people to help me get it. The prosthetic prescription the physician writes is the patient's gateway to the kind of prosthetics that will enable him or her to pursue the activities of their life. Often, new amputees end up with the bare minimum prosthesis, which can cause problems with comfort and mobility. A poorly designed or badly fitting prosthesis is as disabling as the actual amputation. When the surgeon can help the amputee and his or her family understand what kind of prosthetic choices are available, it establishes an optimistic outlook that is highly beneficial to the entire recovery process physically and mentally. "When I lost my leg, if someone would have told me that I could at least try to run again, that would have meant a lot," said Brian Frasure. "Getting that positive mental attitude is every bit as important as having good medical and prosthetic care." By asking probing questions about the patient's preamputation lifestyle and postamputation goals, the physician can write a prescription for truly adaptive prosthetics. The surgeon should

  10. An objective signature for visual binding of face parts in the human brain.

    Science.gov (United States)

    Boremanse, Adriano; Norcia, Anthony M; Rossion, Bruno

    2013-09-10

    Whether and how the parts of a visual object are grouped together to form an integrated ("holistic") representation is a central question in cognitive neuroscience. Although the face is considered to be the quintessential example of holistic representation, this issue has been the subject of much debate in face perception research. The implication of holistic processing is that the response to the whole cannot be predicted from the sum of responses to the parts. Here we apply techniques from nonlinear systems analysis to provide an objective measure of the nonlinear integration of parts into a whole, using the left and right halves of a face stimulus as the parts. High-density electroencephalogram (EEG) was recorded in 15 human participants presented with two halves of a face stimulus, flickering at different frequencies (5.88 vs. 7.14 Hz). Besides specific responses at these fundamental frequencies, reflecting part-based responses, we found intermodulation components (e.g., 7.14 - 5.88 = 1.26 Hz) over the right occipito-temporal hemisphere, reflecting nonlinear integration of the face halves. Part-based responses did not depend on the relative alignment of the two face halves, their spatial separation, or whether the face was presented upright or inverted. By contrast, intermodulations were virtually absent when the two halves were spatially misaligned and separated. Inversion of the whole face configuration also reduced specifically the intermodulation components over the right occipito-temporal cortex. These observations indicate that the intermodulation components constitute an objective, configuration-specific signature of an emergent neural representation of the whole face that is distinct from that generated by the parts themselves.

  11. Prosthetic Valve Thrombosis: Diagnosis and Management.

    Science.gov (United States)

    Garg, Jalaj; Palaniswamy, Chandrasekar; Pinnamaneni, Sowmya; Sarungbam, Judy; Jain, Diwakar

    2016-01-01

    St. Jude mechanical prosthesis is the most commonly used prosthetic device with least valvular complications with excellent hemodynamics. However, prosthetic valve thrombosis is one of the serious complications, with rates between 0.03% and 0.13% per patient-year depending on the type of anticoagulation used and compliance to the therapy. Transthoracic echocardiography (TTE) is the initial screening tool (class I) that would provide clues for the assessment of valvular hemodynamics. Fluoroscopy is an alternate imaging modality for the assessment of mechanical leaflet motion, especially in patients when prosthetic valves are difficult to image on TTE or transesophageal echocardiography. A complete fluoroscopic evaluation of a prosthetic valve includes assessment of valvular motion and structural integrity. Opening and closing angles can be measured fluoroscopically to determine whether a specific valve is functioning properly. We discuss a case of a 91-year-old man with thrombosis of bileaflet mechanical mitral prosthesis that was demonstrated on real-time fluoroscopy (not evident on TTE). An algorithmic approach to diagnosis and management of prosthetic heart valve thrombosis is outlined.

  12. Analogue mouse pointer control via an online steady state visual evoked potential (SSVEP) brain-computer interface

    Science.gov (United States)

    Wilson, John J.; Palaniappan, Ramaswamy

    2011-04-01

    The steady state visual evoked protocol has recently become a popular paradigm in brain-computer interface (BCI) applications. Typically (regardless of function) these applications offer the user a binary selection of targets that perform correspondingly discrete actions. Such discrete control systems are appropriate for applications that are inherently isolated in nature, such as selecting numbers from a keypad to be dialled or letters from an alphabet to be spelled. However motivation exists for users to employ proportional control methods in intrinsically analogue tasks such as the movement of a mouse pointer. This paper introduces an online BCI in which control of a mouse pointer is directly proportional to a user's intent. Performance is measured over a series of pointer movement tasks and compared to the traditional discrete output approach. Analogue control allowed subjects to move the pointer faster to the cued target location compared to discrete output but suffers more undesired movements overall. Best performance is achieved when combining the threshold to movement of traditional discrete techniques with the range of movement offered by proportional control.

  13. Towards an optimization of stimulus parameters for brain-computer interfaces based on steady state visual evoked potentials.

    Directory of Open Access Journals (Sweden)

    Anna Duszyk

    Full Text Available Efforts to construct an effective brain-computer interface (BCI system based on Steady State Visual Evoked Potentials (SSVEP commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems.

  14. Ictal and interictal 99mTc-HMPAO brain SPECT of a MELAS case presented with epilepsy-like visual hallucination.

    Science.gov (United States)

    Wei, Cheng-Yu; Hsiao, Heng-Long; Chen, Shang-Chi; Hung, Guang-Uei; Kao, Chia-Hung

    2012-09-01

    A 55-year-old woman was diagnosed with the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). She was referred for Tc-HMPAO brain SPECT because of visual hallucinations, which were suspected to be related to epileptic seizures. Ictal SPECT images showed remarkable hyperperfusion in the left occipital cortex, which returned to near-normal status on the interictal SPECT images after treatment with anticonvulsants. It is very rare to see such an ictal SPECT image of epileptic or epilepsy-like disorders, especially in the setting of MELAS syndrome with visual hallucination.

  15. Raoultella ornithinolytica: An unusual pathogen for prosthetic joint infection.

    Science.gov (United States)

    Seng, Piseth; Theron, Françoise; Honnorat, Estelle; Prost, Didier; Fournier, Pierre-Edouard; Stein, Andreas

    2016-01-01

    We herein report the first case of a prosthetic joint infection caused by Raoultella ornithinolytica in an immunocompetent patient. The clinical outcome was favorable after a two-stage prosthetic exchange and a six-month course of antimicrobial therapy.

  16. Detection and identification of microbes in prosthetic joint infections by culture and molecular methods

    DEFF Research Database (Denmark)

    Xu, Yijuan; Schønheyder, Henrik Carl; Ehrlich, Garth;

    uncovered many more species including known pathogens and species not previously reported in orthopedic infections, and polymicrobial communities were commonly observed. Additionally the molecular findings suggested the bacterial composition and yield varied depending on the position and type of samples...... used for analysis, particularly prosthetic implants yielded more positive results. Furthermore, the presence of bacteria as both single cells and microcolonies were visualized by fluorescence in situ hybridization using peptide nucleic acid and DNA probes and confocal scanning laser microscopy...

  17. Adaptive sports technology and biomechanics: prosthetics.

    Science.gov (United States)

    De Luigi, Arthur Jason; Cooper, Rory A

    2014-08-01

    With the technologic advances in medicine and an emphasis on maintaining physical fitness, the population of athletes with impairments is growing. It is incumbent upon health care practitioners to make every effort to inform these individuals of growing and diverse opportunities and to encourage safe exercise and athletic participation through counseling and education. Given the opportunities for participation in sports for persons with a limb deficiency, the demand for new, innovative prosthetic designs is challenging the clinical and technical expertise of the physician and prosthetist. When generating a prosthetic prescription, physicians and prosthetists should consider the needs and preferences of the athlete with limb deficiency, as well as the functional demands of the chosen sporting activity. The intent of this article is to provide information regarding the current advancements in the adaptive sports technology and biomechanics in the field of prosthetics, and to assist clinicians and their patients in facilitating participation in sporting activities.

  18. Changes in lower extremity prosthetic practice.

    Science.gov (United States)

    Trower, Ted A

    2006-02-01

    In recent years, much attention has been given to the revolution in new materials for prosthetics and the components that they have made possible. The average weight of a delivered prosthesis has decreased, currently available components offer improved function and superior symmetry of gait, and limb interfaces provide superior skin protection and comfort. The focus on the features of these components sometimes has led to neglect of the basic elements of prosthetic design--the fit and the alignment. If the fit and alignment are on the mark, an amputee can function at remarkably high levels with rudimentary components. This article discusses the basics of lower extremity prosthetic practice and addresses challenges for the future.

  19. Induced arousal following zolpidem treatment in a vegetative state after brain injury in 7 cases Analysis using visual single photon emission computerized tomography and digitized cerebral state monitor

    Institute of Scientific and Technical Information of China (English)

    Bo Du; Aijun Shan; Di Yang; Wei Xiang

    2008-01-01

    BACKGROUND: Several studies have reported the use of zolpidem for induced arousal after permanent vegetative states. However, changes in brain function and EMG after zolpidem treatment requires further investigation. OBJECTIVE: To investigate the effect of zolpidem, an unconventional drug, on inducing arousal in patients in a permanent vegetative state after brain injury using visual single photon emission computerized tomography and digitized cerebral state monitor. DESIGN: A self-controlled observation. SETTING: Shenzhen People's Hospital.PARTICIPANTS: Seven patients in a permanent vegetative state were selected from the Department of Neurosurgery, Shenzhen People's Hospital from March 2005 to May 2007. The group included 5 males and 2 females, 24–55 years of age, with a mean age of 38.5 years. All seven patients had been in a permanent vegetative statement for at least six months. The patient group included three comatose patients, who had sustained injuries to the cerebral cortex, basal ganglia, or thalamus in motor vehicle accidents, and four patients, who had suffered primary/secondary brain stem injury. Informed consents were obtained from the patients’ relatives. METHODS: The patients brains were imaged by 99Tcm ECD single photon emission computerized tomography prior to treatment with zolpidem [Sanofi Winthrop Industrie, France, code number approved by the State Food & Drug Administration (SFDA) J20040033, specification 10 mg per tablet. At 8:00 p.m., 10 mg zolpidem was dissolved with distilled water and administered through a nasogastric tube at 1 hour before and after treatment and 1 week following treatment, respectively. Visual analysis of cerebral perfusion changes in the injured brain regions before and after treatment was performed. Simultaneously, three monitoring parameters were obtained though a cerebral state monitor, which included cerebral state index, electromyographic index, and burst suppression index. MAIN OUTCOME MEASURES: Comparison

  20. Optimising the prescription of prosthetic technologies (opptec): Outcome measures for evidence based prosthetic practice and use

    LENUS (Irish Health Repository)

    Ryall, Dr Nicola

    2010-01-01

    This study provided a forum for patients and service providers to voice their opinions in what they believe to be the important predictors and outcomes involved in successful rehabilitation following limb loss. To develop a consensus on the most important outcomes and factors to address for both the lower limb and upper limb prosthetic prescription process, the above data relating to lower limb and upper prosthetics were subsequently used in the next phase of the research involving two Delphi surveys of 23 and 53 experts within the lower limb and upper limb amputation and prosthetic field respectively, including users, service providers and researchers.\\r\

  1. Comparative roll-over analysis of prosthetic feet

    NARCIS (Netherlands)

    Curtze, Carolin; Hof, At L.; van Keeken, Helco G.; Halbertsma, Jan P. K.; Postema, Klaas; Otten, Bert

    2009-01-01

    A prosthetic foot is a key element of a prosthetic leg, literally forming the basis for a stable and efficient amputee gait. We determined the roll-over characteristics of a broad range of prosthetic feet and examined the effect of a variety of shoes on these characteristics. The body weight of a pe

  2. Design and properties of maxillofacial prosthetic materials.

    Science.gov (United States)

    Andreopoulos, A G; Theophanides, T

    1993-11-01

    Maxillofacial reconstruction by prosthetic means is a valuable contribution that medicine offers to the public. Materials design and properties are the main problems faced by scientists in this field. Materials used for intraoral prostheses are not ideal, but they have been perfected to the point of practical use. Denture resins, gold, chromium-cobalt alloys, and porcelain are widely used and produce acceptable results in the oral cavity. In this review, the properties and performance of some polymeric materials used in maxillofacial prosthetics are discussed, and new trends in research and development are also reported.

  3. Mesofluidic controlled robotic or prosthetic finger

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Randall F; Jansen, John F; Love, Lonnie J

    2013-11-19

    A mesofluidic powered robotic and/or prosthetic finger joint includes a first finger section having at least one mesofluidic actuator in fluid communication with a first actuator, a second mesofluidic actuator in fluid communication with a second actuator and a second prosthetic finger section pivotally connected to the first finger section by a joint pivot, wherein the first actuator pivotally cooperates with the second finger to provide a first mechanical advantage relative to the joint point and wherein the second actuator pivotally cooperates with the second finger section to provide a second mechanical advantage relative to the joint point.

  4. Centrosomal-ciliary gene CEP290/NPHP6 mutations result in blindness with unexpected sparing of photoreceptors and visual brain: implications for therapy of Leber congenital amaurosis.

    Science.gov (United States)

    Cideciyan, Artur V; Aleman, Tomas S; Jacobson, Samuel G; Khanna, Hemant; Sumaroka, Alexander; Aguirre, Geoffrey K; Schwartz, Sharon B; Windsor, Elizabeth A M; He, Shirley; Chang, Bo; Stone, Edwin M; Swaroop, Anand

    2007-11-01

    Mutations in the centrosomal-ciliary gene CEP290/NPHP6 are associated with Joubert syndrome and are the most common cause of the childhood recessive blindness known as Leber congenital amaurosis (LCA). An in-frame deletion in Cep290 shows rapid degeneration in the rod-rich mouse retina. To explore the mechanisms of the human retinal disease, we studied CEP290-LCA in patients of different ages (7-48 years) and compared results to Cep290-mutant mice. Unexpectedly, blind CEP290-mutant human retinas retained photoreceptor and inner laminar architecture in the cone-rich central retina, independent of severity of visual loss. Surrounding the cone-rich island was photoreceptor loss and distorted retina, suggesting neural-glial remodeling. The mutant mouse retina at 4-6 weeks of age showed similar features of retinal remodeling, with altered neural and synaptic laminae and Muller glial activation. The visual brain pathways in CEP290-LCA were anatomically intact. Our findings of preserved foveal cones and visual brain anatomy in LCA with CEP290 mutations, despite severe blindness and rapid rod cell death, suggest an opportunity for visual restoration of central vision in this common form of inherited blindness.

  5. Visualization and Quantitative Assessment of the Brain Distribution of Insulin through Nose-to-Brain Delivery Based on the Cell-Penetrating Peptide Noncovalent Strategy.

    Science.gov (United States)

    Kamei, Noriyasu; Shingaki, Tomotaka; Kanayama, Yousuke; Tanaka, Misa; Zochi, Riyo; Hasegawa, Koki; Watanabe, Yasuyoshi; Takeda-Morishita, Mariko

    2016-03-07

    Our recent work suggested that intranasal coadministration with the cell-penetrating peptide (CPP) penetratin increased the brain distribution of the peptide drug insulin. The present study aimed to distinctly certify the ability of penetratin to facilitate the nose-to-brain delivery of insulin by quantitatively evaluating the distribution characteristics in brain using radioactive (64)Cu-NODAGA-insulin. Autoradiography and analysis using a gamma counter of brain areas demonstrated that the accumulation of radioactivity was greatest in the olfactory bulb, the anterior part of the brain closest to the administration site, at 15 min after intranasal administration of (64)Cu-NODAGA-insulin with l- or d-penetratin. The brain accumulation of (64)Cu-NODAGA-insulin with penetratin was confirmed by ELISA using unlabeled insulin in which intact insulin was delivered to the brain after intranasal coadministration with l- or d-penetratin. By contrast, quantification of cerebrospinal fluid (CSF) samples showed increased insulin concentration in only the anterior portion of the CSF at 15 min after intranasal coadministration with l-penetratin. This study gives the first concrete proof that penetratin can accelerate the direct transport of insulin from the nasal cavity to the brain parenchyma. Further optimization of intranasal administration with CPP may increase the efficacy of delivery of biopharmaceuticals to the brain while reducing the risk of systemic drug exposure.

  6. Association between striatal dopamine D2/D3 receptors and brain activation during visual attention: effects of sleep deprivation

    Science.gov (United States)

    Tomasi, D; Wang, G-J; Volkow, N D

    2016-01-01

    Sleep deprivation (SD) disrupts dopamine (DA) signaling and impairs attention. However, the interpretation of these concomitant effects requires a better understanding of dopamine's role in attention processing. Here we test the hypotheses that D2/D3 receptors (D2/D3R) in dorsal and ventral striatum would distinctly regulate the activation of attention regions and that, by decreasing D2/D3, SD would disrupt these associations. We measured striatal D2/D3R using positron emission tomography with [11C]raclopride and brain activation to a visual attention (VA) task using 4-Tesla functional magnetic resonance imaging. Fourteen healthy men were studied during rested wakefulness and also during SD. Increased D2/D3R in striatum (caudate, putamen and ventral striatum) were linearly associated with higher thalamic activation. Subjects with higher D2/D3R in caudate relative to ventral striatum had higher activation in superior parietal cortex and ventral precuneus, and those with higher D2/D3R in putamen relative to ventral striatum had higher activation in anterior cingulate. SD impaired the association between striatal D2/D3R and VA-induced thalamic activation, which is essential for alertness. Findings suggest a robust DAergic modulation of cortical activation during the VA task, such that D2/D3R in dorsal striatum counterbalanced the stimulatory influence of D2/D3R in ventral striatum, which was not significantly disrupted by SD. In contrast, SD disrupted thalamic activation, which did not show counterbalanced DAergic modulation but a positive association with D2/D3R in both dorsal and ventral striatum. The counterbalanced dorsal versus ventral striatal DAergic modulation of VA activation mirrors similar findings during sensorimotor processing (Tomasi et al., 2015) suggesting a bidirectional influence in signaling between the dorsal caudate and putamen and the ventral striatum. PMID:27219347

  7. Multimodality Imaging Assessment of Prosthetic Heart Valves

    NARCIS (Netherlands)

    Suchá, D.; Symersky, Petr; Tanis, W; Mali, Willem P Th M; Leiner, Tim; van Herwerden, LA; Budde, Ricardo P J

    2015-01-01

    Echocardiography and fluoroscopy are the main techniques for prosthetic heart valve (PHV) evaluation, but because of specific limitations they may not identify the morphological substrate or the extent of PHV pathology. Cardiac computed tomography (CT) and magnetic resonance imaging (MRI) have emerg

  8. Proceedings, 1972 Carahan Conference on Electronic Prosthetics.

    Science.gov (United States)

    Jackson, John S., Ed.; DeVore, R. William, Ed.

    Presented are 28 papers given at a 1972 conference on electronic prosthetics for the handicapped. Among the papers are the following titles: "Therapy for Cerebral Palsy Employing Artifician Sense Organs for Alternatives to Proprioceptive Feedback"; "Excessive Neuromuscular Time Delay as a Possible Cause of Poor Hand-Eye Coordination and…

  9. The Prosthetic Experience Between Body and Technology

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    2018-01-01

    In this paper, I argue that a prosthetic aesthetic instigated by experimental art practices operate with and within a ‘second nature’ – in-between science and art. Drawing on theories from Dewey and Edelman and examples from Da Vinci, Brancusi, Man Ray, Dali and Stelarc, I am calling for an exper...

  10. Consumer satisfaction in prosthetics and orthotics facilities

    NARCIS (Netherlands)

    Geertzen, J.H.B.; Gankema, H.G.J.; Groothoff, J.W.; Dijkstra, P.U.

    2002-01-01

    The aim of this study was to assess consumer/patient satisfaction with the services of the prosthetics and orthotics (P&O) facilities in the north of the Netherlands, using a modified SERVQUAL questionnaire. In this questionnaire, consumer interests and experiences are assessed on a 5-point Likert s

  11. Development and Use of Visual Explanations: Harnessing the Power of the "Seeing" Brain to Enhance Student Learning

    Science.gov (United States)

    Schmidt, Shelly J.

    2009-01-01

    When students come to class, they bring with them the most powerful processor known to man--the human brain! Our job as teachers is to discover and implement practices that will make the most effective use of those brains. The human brain is a very powerful processor of sensory information, especially with regard to the sense of vision. We can…

  12. Using thin-film piezoelectret to detect tactile and slip signals for restoring sensation of prosthetic hands.

    Science.gov (United States)

    Fang, Peng; Tian, Lan; Zheng, Yue; Huang, Jianping; Li, Guanglin

    2014-01-01

    Most of the currently available prosthetic hands do not have a proper sensation of touching and slipping. Thus it is not easy for arm amputees to grasp objects properly only with an assistance of visual feedback. In this pilot work, a sensor based on thin-film piezoelectret was used to detect the possible tactile and slip information of a prosthetic hand. The piezoelectret sensor is flexible and is able to be bended, and therefore it could be properly mounted on the surface of prosthetic finger. Our preliminary results demonstrated that both the tactile and slip information could be acquired with the same sensor unit. For a grasp without slippage, the tactile signal was usually a single large peak, whereas the slip signal was a series of vibrations in a small range. Thus these two types of signals could be easily separated based on their different characteristics. This study suggested that by using thin-film piezoelectret sensor, a primary control with involuntary feedback might be achieved for the present prosthetic hands. More studies would be required on the detailed signal processing and control strategy for the restoration of sensation function in prosthetic hands.

  13. Simulated Prosthetic Vision: The Benefits of Computer-Based Object Recognition and Localization.

    Science.gov (United States)

    Macé, Marc J-M; Guivarch, Valérian; Denis, Grégoire; Jouffrais, Christophe

    2015-07-01

    Clinical trials with blind patients implanted with a visual neuroprosthesis showed that even the simplest tasks were difficult to perform with the limited vision restored with current implants. Simulated prosthetic vision (SPV) is a powerful tool to investigate the putative functions of the upcoming generations of visual neuroprostheses. Recent studies based on SPV showed that several generations of implants will be required before usable vision is restored. However, none of these studies relied on advanced image processing. High-level image processing could significantly reduce the amount of information required to perform visual tasks and help restore visuomotor behaviors, even with current low-resolution implants. In this study, we simulated a prosthetic vision device based on object localization in the scene. We evaluated the usability of this device for object recognition, localization, and reaching. We showed that a very low number of electrodes (e.g., nine) are sufficient to restore visually guided reaching movements with fair timing (10 s) and high accuracy. In addition, performance, both in terms of accuracy and speed, was comparable with 9 and 100 electrodes. Extraction of high level information (object recognition and localization) from video images could drastically enhance the usability of current visual neuroprosthesis. We suggest that this method-that is, localization of targets of interest in the scene-may restore various visuomotor behaviors. This method could prove functional on current low-resolution implants. The main limitation resides in the reliability of the vision algorithms, which are improving rapidly.

  14. Motor, Visual and Emotional Deficits in Mice after Closed-Head Mild Traumatic Brain Injury Are Alleviated by the Novel CB2 Inverse Agonist SMM-189

    Directory of Open Access Journals (Sweden)

    Anton Reiner

    2014-12-01

    Full Text Available We have developed a focal blast model of closed-head mild traumatic brain injury (TBI in mice. As true for individuals that have experienced mild TBI, mice subjected to 50–60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2, we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50–60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.

  15. Motor, visual and emotional deficits in mice after closed-head mild traumatic brain injury are alleviated by the novel CB2 inverse agonist SMM-189.

    Science.gov (United States)

    Reiner, Anton; Heldt, Scott A; Presley, Chaela S; Guley, Natalie H; Elberger, Andrea J; Deng, Yunping; D'Surney, Lauren; Rogers, Joshua T; Ferrell, Jessica; Bu, Wei; Del Mar, Nobel; Honig, Marcia G; Gurley, Steven N; Moore, Bob M

    2014-12-31

    We have developed a focal blast model of closed-head mild traumatic brain injury (TBI) in mice. As true for individuals that have experienced mild TBI, mice subjected to 50-60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2), we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50-60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.

  16. Analysis of brain-stem auditory evoked potential and visual evoked potential in patients with Parkinson disease

    Institute of Scientific and Technical Information of China (English)

    Qiaorong Deng; Jianzhong Deng; Yanmin Zhao; Xiaohai Yan; Pin Chen

    2006-01-01

    BACKGROUND: With the development of neuroelectrophysiology, it had been identified that all kinds of evoked potentials might reflect the functional status of corresponding pathway. Evoked potentials recruited in the re search of PD, it can be known whether other functional pathway of nervous system is impaired. OBJECTIVE: To observe whether brainstem auditory and visual passageway are impaired in patients with Parkinson disease (PD), and compare with non-PD patients concurrently. DESIGN: A non-randomized concurrent controlled observation. SETTINGS: Henan Provincial Tumor Hospital; Anyang District Hospital. PARTICIPANTS: Thirty-two cases of PD outpatients and inpatients, who registered in the Department of Neurology, Anyang District Hospital from October 1997 to February 2006, were enrolled as the PD group, including 20 males and 12 females, aged 50-72 years old. Inclusive criteria: In accordance with the diagnostic criteria of PD recommended by the dyskinesia and PD group of neurology branch of Chinese Medical Association. Patients with diseases that could cause Parkinson syndrome were excluded by CT scanning or MRI examination. Meanwhile, 30 cases with non-neurological disease were selected from the Department of Internal Medicine of our hospital as the control group, including 19 males and 11 females, aged 45-70 years old. Including criteria: Without history of neurological disease or psychiatric disease; showing normal image on CT. And PD, Parkinson syndrome and Parkinsonism-plus were excluded by professional neurologist. All the patients were informed and agreed with the examination and clinical observation. METHODS: The electrophysiological examination and clinical observation of the PD patients and controls were conducted. The Reporter type 4-channel evoked potential machine (Italy) was used to check brain-stem auditory evoked potential (BAEP) and visual evoked potential (VEP). Why to be examined was explained to test taker. BAEP recording electrode was plac

  17. An Approach for Pattern Recognition of EEG Applied in Prosthetic Hand Drive

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Zhang

    2011-12-01

    Full Text Available For controlling the prosthetic hand by only electroencephalogram (EEG, it has become the hot spot in robotics research to set up a direct communication and control channel between human brain and prosthetic hand. In this paper, the EEG signal is analyzed based on multi-complicated hand activities. And then, two methods of EEG pattern recognition are investigated, a neural prosthesis hand system driven by BCI is set up, which can complete four kinds of actions (arm’s free state, arm movement, hand crawl, hand open. Through several times of off-line and on-line experiments, the result shows that the neural prosthesis hand system driven by BCI is reasonable and feasible, the C-support vector classifiers-based method is better than BP neural network on the EEG pattern recognition for multi-complicated hand activities.

  18. Neuroengineering tools/applications for bidirectional interfaces, brain computer interfaces, and neuroprosthetic implants - a review of recent progress

    Directory of Open Access Journals (Sweden)

    Ryan M Rothschild

    2010-10-01

    Full Text Available The main focus of this review is to provide a holistic amalgamated overview of the most recent human in vivo techniques for implementing brain-computer interfaces (BCIs, bidirectional interfaces and neuroprosthetics. Neuroengineering is providing new methods for tackling current difficulties; however neuroprosthetics have been studied for decades. Recent progresses are permitting the design of better systems with higher accuracies, repeatability and system robustness. Bidirectional interfaces integrate recording and the relaying of information from and to the brain for the development of BCIs. The concepts of non-invasive and invasive recording of brain activity are introduced. This includes classical and innovative techniques like electroencephalography (EEG and near-infrared spectroscopy (NIRS. Then the problem of gliosis and solutions for (semi- permanent implant biocompatibility such as innovative implant coatings, materials and shapes are discussed. Implant power and the transmission of their data through implanted pulse generators (IPGs and wireless telemetry are taken into account. How sensation can be relayed back to the brain to increase integration of the neuroengineered systems with the body by methods such as micro-stimulation and transcranial magnetic stimulation (TMS are then addressed. The neuroprosthetic section discusses some of the various types and how they operate. Visual prosthetics are discussed and the three types, dependant on implant location, are examined. Auditory prosthetics, being cochlear or cortical, are then addressed. Replacement hand and limb prosthetics are then considered. These are followed by sections concentrating on the control of wheelchairs, computers and robotics directly from brain activity as recorded by non-invasive and invasive techniques.

  19. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.

    1985-01-01

    This book consists of essays covering issues in visual cognition presenting experimental techniques from cognitive psychology, methods of modeling cognitive processes on computers from artificial intelligence, and methods of studying brain organization from neuropsychology. Topics considered include: parts of recognition; visual routines; upward direction; mental rotation, and discrimination of left and right turns in maps; individual differences in mental imagery, computational analysis and the neurological basis of mental imagery: componental analysis.

  20. Matching prosthetics order records in VA National Prosthetics Patient Database to healthcare utilization databases.

    Science.gov (United States)

    Smith, Mark W; Su, Pon; Phibbs, Ciaran S

    2010-01-01

    The National Prosthetics Patient Database (NPPD) is the national Department of Veterans Affairs (VA) dataset that records characteristics of individual prosthetic and assistive devices. It remains unknown how well NPPD records can be matched to encounter records for the same individuals in major VA utilization databases. We compared the count of prosthetics records in the NPPD with the count of prosthetics-related procedures for the same individuals recorded in major VA utilization databases. We then attempted to match the NPPD records to the utilization records by person and date. In general, 40% to 60% of the NPPD records could be matched to outpatient utilization records within a 14-day window around the NPPD dataset entry date. Match rates for inpatient data were lower: 10% to 16% within a 14-day window. The NPPD will be particularly important for studies of certain veteran groups, such as those with spinal cord injury or blast-related polytraumatic injury. Health services researchers should use both the NPPD and utilization databases to develop a full understanding of prosthetics use by individual patients.

  1. History of the prosthetic treatment of impotence.

    Science.gov (United States)

    Bretan, P N

    1989-02-01

    Early records of observations of the os penis or baculum in mammals go back to Aristotle. These heritable cartilaginous supports were noted to help the penis during copulation. Prosthetic surgery for treatment of impotence was born from the initial experience with the use of the "artificial os penis" (rib cartilage) in post-traumatic reconstruction in 1936. Slow progress was made with the use of extracavernosal acrylic stents, followed by intracavernosal polypropylene rods, and finally the silicone prosthesis over the next 20 years. The introduction in 1973 of the inert silicone semirigid prosthesis and inflatable prosthesis met with great successes. Most recently (1985), there has been development of self-contained prostheses that are technically more simple to insert. Today, much more is known about specific organic causes of impotence that are amenable to many successful nonprosthetic alternative therapies, adding more stimuli to continued innovations in prosthetic surgery for erectile dysfunction.

  2. Measuring the color of maxillofacial prosthetic material.

    Science.gov (United States)

    Hu, X; Johnston, W M; Seghi, R R

    2010-12-01

    Color information from different color-measuring systems varies during color matching in maxillofacial prosthetics. We studied the hypothesis that a non-contact measuring system and 4 contact color-measuring instruments perform comparably in accuracy and precision on measurements of pigmented maxillofacial elastomer specimens having human skin colors. Measurement comparisons in accuracy on opaque standard color patches were made in Phase I. In Phase II, the system with the best accuracy was used as the reference instrument, and comparisons in accuracy and precision on elastomer specimens were made. The CIEDE2000 color difference formula was used. Repeated-measures ANOVA with Tukey testing and linear regression analysis for CIELAB and color differences among the instruments were performed. The contact measuring systems perform differently in accuracy, possibly due to edge loss and other factors, but performed comparably in precision with the non-contact measuring instrument. This non-contact system is recommended for color measurement of maxillofacial prosthetic materials.

  3. Design of a Compact, Reconfigurable, Prosthetic Wrist

    Directory of Open Access Journals (Sweden)

    Arthur Zinck

    2012-01-01

    Full Text Available The design of a prosthetic wrist is the result of compromises between the function and the practicality of the device. Conventional prosthetic wrists use a single degree of freedom to produce pro/supination of the hand. It has not been demonstrated that this is the most functional alignment for a single axis. Previous work by the authors suggests that if the wrist must have only one rotatory axis then a more oblique orientation would be more functional. To test this idea, a compact wrist with a single axis and spherical design has been made that will allow any axis of rotation to be selected and the functional performance of the resulting arm be tested.

  4. Does Silent Reading Speed in Normal Adult Readers Depend on Early Visual Processes? Evidence from Event-Related Brain Potentials

    Science.gov (United States)

    Korinth, Sebastian Peter; Sommer, Werner; Breznitz, Zvia

    2012-01-01

    Little is known about the relationship of reading speed and early visual processes in normal readers. Here we examined the association of the early P1, N170 and late N1 component in visual event-related potentials (ERPs) with silent reading speed and a number of additional cognitive skills in a sample of 52 adult German readers utilizing a Lexical…

  5. New developments in prosthetic arm systems

    Directory of Open Access Journals (Sweden)

    Vujaklija I

    2016-07-01

    Full Text Available Ivan Vujaklija,1 Dario Farina,1 Oskar C Aszmann2 1Institute of Neurorehabilitation Systems, Bernstein Focus Neurotechnology Göttingen, University Medical Center Göttingen, Georg-August University, Göttingen, Germany; 2Christian Doppler Laboratory for Restoration of Extremity Function, Division of Plastic and Reconstructive Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria Abstract: Absence of an upper limb leads to severe impairments in everyday life, which can further influence the social and mental state. For these reasons, early developments in cosmetic and body-driven prostheses date some centuries ago, and they have been evolving ever since. Following the end of the Second World War, rapid developments in technology resulted in powered myoelectric hand prosthetics. In the years to come, these devices were common on the market, though they still suffered high user abandonment rates. The reasons for rejection were trifold – insufficient functionality of the hardware, fragile design, and cumbersome control. In the last decade, both academia and industry have reached major improvements concerning technical features of upper limb prosthetics and methods for their interfacing and control. Advanced robotic hands are offered by several vendors and research groups, with a variety of active and passive wrist options that can be articulated across several degrees of freedom. Nowadays, elbow joint designs include active solutions with different weight and power options. Control features are getting progressively more sophisticated, offering options for multiple sensor integration and multi-joint articulation. Latest developments in socket designs are capable of facilitating implantable and multiple surface electromyography sensors in both traditional and osseointegration-based systems. Novel surgical techniques in combination with modern, sophisticated hardware are enabling restoration of dexterous upper limb

  6. Maxillofacial Prosthetic Materials- An Inclination Towards Silicones

    OpenAIRE

    Mitra, Aparajita; Choudhary, Sunita; Garg, Hemlata; H.G., Jagadeesh

    2014-01-01

    There have been constant searches and researches which are taking place in the field of dental materials to best suit the ideal selection criteria to satisfy the functionality, biocompatibility, aesthetics as well as the durability as a maxillofacial material. Among all the different materials, Silicone is the most popularly used, but still studies are carried out to overcome their weaknesses and to come out with a material which can be labeled as the “ideal maxillofacial prosthetic material”...

  7. Prosthetic management of an ocular defect

    Directory of Open Access Journals (Sweden)

    Siddesh Kumar Chintal

    2010-01-01

    Full Text Available The disfigurement associated with the loss of an eye can cause significant physical and emotional problems. Various treatment modalities are available, one of which is implants. Although implant has a superior outcome, it may not be advisable in all patients due to economic factors. The present article describes the prosthetic management of an ocular defect with a custom-made ocular prosthesis.

  8. Tactile Sensing Reflexes for Advanced Prosthetic Hands

    Science.gov (United States)

    2016-10-01

    Quad Chart 37 1. INTRODUCTION: The purpose of this research is to equip a myoelectric prosthetic hand with contact detecting sensors and a...controller to perform contact detection reflex (11-13 mos.) 80% • Program controller to perform software functions for clinical studies (12-13 mos.) 60...candidates have been ordered, and are having pressure relief holes laser drilled . A custom flexible component board that holds the pressure sensor

  9. Prosthetic Hand With Two Gripping Fingers

    Science.gov (United States)

    Norton, William E.; Belcher, Jewell B.; Vest, Thomas W.; Carden, James R.

    1993-01-01

    Prosthetic hand developed for amputee who retains significant portion of forearm. Outer end of device is end effector including two fingers, one moved by rotating remaining part of forearm about its longitudinal axis. Main body of end effector is end member supporting fingers, roller bearing assembly, and rack-and-pinion mechanism. Advantage of rack-and-pinion mechanism enables user to open or close gap between fingers with precision and force.

  10. Matching spatial with ontological brain regions using Java tools for visualization, database access, and integrated data analysis.

    NARCIS (Netherlands)

    Bezgin, G.; Reid, A.T.; Schubert, D.; Kotter, R.

    2009-01-01

    Brain atlases are widely used in experimental neuroscience as tools for locating and targeting specific brain structures. Delineated structures in a given atlas, however, are often difficult to interpret and to interface with database systems that supply additional information using hierarchically o

  11. Combined brain and anterior visual pathways' MRIs assist in early identification of neuromyelitis optica spectrum disorder at onset of optic neuritis.

    Science.gov (United States)

    Buch, D; Savatovsky, J; Gout, O; Vignal, C; Deschamps, R

    2017-03-01

    Acute optic neuritis (ON) is the initial presentation in half of neuromyelitis optica spectrum disorder (NMO-SD) cases. Our objective was to evaluate accuracy of combined MRIs of the anterior visual pathways and of the brain to correctly identify NMO-SD among patients with acute ON. We performed a retrospective study on patients with acute ON in NMO-SD (16 episodes) and first-event non-NMO-SD (32 episodes). All MRIs included exams of the brain and anterior visual pathways using T2-weighted and post-gadolinium T1-weighted coronal thin slices. Images were reviewed by a neuroradiologist who was blinded to the final diagnosis. There were no multiple sclerosis (MS)-like lesions with dissemination in space (DIS) with NMO-SD (0 vs. 53%, p < 0.01). Non-NMO-SD ON usually spared the chiasma (3 vs. 44%, p < 0.01) and the optic tracts (0 vs. 19%, p < 0.01). Optic nerve lesions were longer [median (range) 26 mm (14-64) vs. 13 mm [8-36], p < 0.01] and the number of segments involved higher (3 [1-8] vs. 1 [1-4], p < 0.01) in NMO-SD. Bilateral optic nerve involvement, or involvement of ≥3 segments, or involvement of the chiasma, or optic tracts in the absence of MS-like lesions with DIS were suggestive of NMO-SD with a sensitivity of 69% (CI 95% 41-89) and a specificity of 97% (CI 95% 84-99) (p < 0.01). Combining brain and anterior visual pathways' MRIs seems efficient for detecting acute ON patients who are at high risk for NMO-SD.

  12. Evidence of a visual-to-auditory cross-modal sensory gating phenomenon as reflected by the human P50 event-related brain potential modulation.

    Science.gov (United States)

    Lebib, Riadh; Papo, David; de Bode, Stella; Baudonnière, Pierre Marie

    2003-05-08

    We investigated the existence of a cross-modal sensory gating reflected by the modulation of an early electrophysiological index, the P50 component. We analyzed event-related brain potentials elicited by audiovisual speech stimuli manipulated along two dimensions: congruency and discriminability. The results showed that the P50 was attenuated when visual and auditory speech information were redundant (i.e. congruent), in comparison with this same event-related potential component elicited with discrepant audiovisual dubbing. When hard to discriminate, however, bimodal incongruent speech stimuli elicited a similar pattern of P50 attenuation. We concluded to the existence of a visual-to-auditory cross-modal sensory gating phenomenon. These results corroborate previous findings revealing a very early audiovisual interaction during speech perception. Finally, we postulated that the sensory gating system included a cross-modal dimension.

  13. Visualization of early infarction in rat brain after ischemia using a translocator protein (18 kDa) PET ligand [11C]DAC with ultra-high specific activity.

    Science.gov (United States)

    Yui, Joji; Hatori, Akiko; Kawamura, Kazunori; Yanamoto, Kazuhiko; Yamasaki, Tomoteru; Ogawa, Masanao; Yoshida, Yuichiro; Kumata, Katsushi; Fujinaga, Masayuki; Nengaki, Nobuki; Fukumura, Toshimitsu; Suzuki, Kazutoshi; Zhang, Ming-Rong

    2011-01-01

    The aim of this study was to visualize early infarction in the rat brain after ischemia using a translocator protein (TSPO) (18 kDa) PET ligand [(11)C]DAC with ultra-high specific activity (SA) of 3670-4450 GBq/μmol. An infarction model of rat brain was prepared by ischemic surgery and evaluated 2 days after ischemia using small-animal PET and in vitro autoradiography. Early infarction with a small increase of TSPO expression in the brain was visualized using PET with high SA [(11)C]DAC (average 4060 GBq/μmol), but was not distinguished clearly with usually reported SA [(11)C]DAC (37 GBq/μmol). Infarction in the rat brain 4 days after ischemia was visualized using high and usually reported SAs [(11)C]DAC. Displacement experiments with unlabeled TSPO-selective AC-5216 or PK11195 diminished the difference in radioactivity between ipsilateral and contralateral sides, confirming that the increased uptake on the infracted brain was specific to TSPO. In vitro autoradiography with high SA [(11)C]DAC showed that the TSPO expression increased on early infarction in the rat brain. High SA [(11)C]DAC is a useful and sensitive biomarker for the visualization of early infarction and the characterization of TSPO expression which was slightly elevated in the infarcted brain using PET.

  14. Behavior of parasite-specific effector CD8+ T cells in the brain and visualization of a kinesis-associated system of reticular fibers.

    Science.gov (United States)

    Wilson, Emma H; Harris, Tajie H; Mrass, Paulus; John, Beena; Tait, Elia D; Wu, Gregory F; Pepper, Marion; Wherry, E John; Dzierzinski, Florence; Roos, David; Haydon, Philip G; Laufer, Terri M; Weninger, Wolfgang; Hunter, Christopher A

    2009-02-20

    To understand lymphocyte behavior in the brain, we used two-photon microscopy to visualize effector CD8(+) T cells during toxoplasmic encephalitis. These cells displayed multiple behaviors with two distinct populations of cells apparent: one with a constrained pattern of migration and one with a highly migratory subset. The proportion of these populations varied over time associated with changes in antigen availability as well as T cell expression of the inhibitory receptor PD1. Unexpectedly, the movement of infiltrating cells was closely associated with an infection-induced reticular system of fibers. This observation suggests that, whereas in other tissues pre-existing scaffolds exist that guide lymphocyte migration, in the brain specialized structures are induced by inflammation that guide migration of T cells in this immune-privileged environment.

  15. [Optogenetics and prosthetic treatment of retinal degeneration].

    Science.gov (United States)

    Kirpichnikov, M P; Ostrovskiy, M A

    2015-01-01

    This is a review of the current state of optogenetics-based research in the field of ophthalmology and physiology of vision. Optogenetics employs an interdisciplinary approach that amalgamates gene engineering, optics, and physiology. It involves exogenous expression of a light-activated protein in a very particular retinal cell enabling regulation (stimulation vs. inhibition) of its physiological activity. The experience with gene therapy came in very useful for optogenetics. However, unlike gene therapy, which is aimed at repairing damaged genes or replacing them with healthy ones, optogenetics is focused on protein genes delivery for further molecular control of the cell. In retina, the loss of photoreceptors is not necessarily followed by neuronal loss (at least ganglion cells remain intact), which determines the practicability of prosthetic treatment. Clinical trials can now be considered, owing to the first successful conversion of ganglion cells of mouse degenerative retinas into artificial photoreceptive cells with ON and OFF receptive fields, which is crucial for spatial vision. The following issues are reviewed here in detail: 1. Choice of cell targets within the degenerative retina. 2. Strategy of utilizing the existing light-sensitive agents and development of new optogenetic tools. 3. Gene delivery and expression in retinal cells. 4. Methods of evaluating the treatment success. 5. Selection criteria for optogenetic prosthetics. The conclusion discusses currently unsolved problems and prospects for optogenetic approaches to retinal prosthetics.

  16. Evaluation of the binding characteristics of [{sup 18}F]fluoroproxyfan in the rat brain for in vivo visualization of histamine H{sub 3} receptor

    Energy Technology Data Exchange (ETDEWEB)

    Funaki, Yoshihito [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan)], E-mail: zen@cyric.tohoku.ac.jp; Sato, Kimihiko [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Kato, Motohisa [Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Ishikawa, Yoichi; Iwata, Ren [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Yanai, Kazuhiko [Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan)

    2007-11-15

    Histamine H{sub 3} receptors play an important role in biological functions. The aim of this research was to examine whether histamine H{sub 3} receptors can be visualized in vivo and in vitro with [{sup 18}F]3-(1H-imidazol-4-yl)propyl 4-fluorobenzyl ether (fluoroproxyfan). [{sup 18}F]Fluoroproxyfan was synthesized with high specific activity using [{sup 18}F]benzyl bromide. The binding of [{sup 18}F]fluoroproxyfan to rat brain homogenates was higher in the striatum and thalamus and was lowest in the cerebellum. The in vitro autoradiographic study successfully demonstrated the specific binding of [{sup 18}F]fluoroproxyfan to the H{sub 3} receptor in the rat brain. In accordance with the in vitro bindings, the in vivo distribution of [{sup 18}F]fluoroproxyfan was heterogeneous in the rat brain. In the blocking experiments, the heterogeneous distribution disappeared in the presence of large amounts of fluoroproxyfan. These data suggest that [{sup 18}F]fluoroproxyfan can be potentially useful to image histamine H{sub 3} receptor noninvasively in the human brain by positron emission tomography.

  17. 100 top-cited scientific papers in limb prosthetics

    OpenAIRE

    Eshraghi, Arezoo; Osman, Noor Azuan Abu; Gholizadeh, Hossein; Ali, Sadeeq; Shadgan, Babak

    2013-01-01

    Research has tremendously contributed to the developments in both practical and fundamental aspects of limb prosthetics. These advancements are reflected in scientific articles, particularly in the most cited papers. This article aimed to identify the 100 top-cited articles in the field of limb prosthetics and to investigate their main characteristics. Articles related to the field of limb prosthetics and published in the Web of Knowledge database of the Institute for Scientific Information (...

  18. Prosthetic options available for the diabetic lower limb amputee.

    Science.gov (United States)

    Chitragari, Gautham; Mahler, David B; Sumpio, Brandon J; Blume, Peter A; Sumpio, Bauer E

    2014-01-01

    Although the rate of lower limb amputation in patients with diabetes is decreasing, amputation still remains a major complication of diabetes. Prosthetics have been long used to help amputees ambulate. The last decade has seen many advances in prostheses with the enhanced understanding of the mechanics of ambulation and improved use of technology. This review describes the different types of prosthetic options available for below knee, ankle, and foot amputees, emphasizing the latest advances in prosthetic design.

  19. Below knee prosthetic socket designs and suspension systems.

    Science.gov (United States)

    Edwards, M L

    2000-08-01

    The prosthetic socket must act as a customized connection between the residual limb's surrounding tissues and the prosthetic components. The socket must be designed to control weight bearing, suspension, and ambulation stability. When making a below-the-knee socket, the prosthetist attempts to maximize loading and minimize displacements, such as vertical, transverse, or rotational. This article discusses the engineering designs or shapes of the two basic forms of below-the-knee prosthetic sockets used today.

  20. An extremely lightweight fingernail worn prosthetic interface device

    Science.gov (United States)

    Yetkin, Oguz; Ahluwalia, Simranjit; Silva, Dinithi; Kasi-Okonye, Isioma; Volker, Rachael; Baptist, Joshua R.; Popa, Dan O.

    2016-05-01

    Upper limb prosthetics are currently operated using several electromyography sensors mounted on an amputee's residual limb. In order for any prosthetic driving interface to be widely adopted, it needs to be responsive, lightweight, and out of the way when not being used. In this paper we discuss the possibility of replacing such electrodes with fingernail optical sensor systems mounted on the sound limb. We present a prototype device that can detect pinch gestures and communicate with the prosthetic system. The device detects the relative position of fingers to each other by measuring light transmitted via tissue. Applications are not limited to prosthetic control, but can be extended to other human-machine interfaces.

  1. 21 CFR 890.3420 - External limb prosthetic component.

    Science.gov (United States)

    2010-04-01

    ... total prosthesis. Examples of external limb prosthetic components include the following: Ankle, foot... shoulder joint components; and cable and prosthesis suction valves. (b) Classification. Class I...

  2. The role of osteoblasts in peri-prosthetic osteolysis.

    LENUS (Irish Health Repository)

    O'Neill, S C

    2013-08-01

    Peri-prosthetic osteolysis and subsequent aseptic loosening is the most common reason for revising total hip replacements. Wear particles originating from the prosthetic components interact with multiple cell types in the peri-prosthetic region resulting in an inflammatory process that ultimately leads to peri-prosthetic bone loss. These cells include macrophages, osteoclasts, osteoblasts and fibroblasts. The majority of research in peri-prosthetic osteolysis has concentrated on the role played by osteoclasts and macrophages. The purpose of this review is to assess the role of the osteoblast in peri-prosthetic osteolysis. In peri-prosthetic osteolysis, wear particles may affect osteoblasts and contribute to the osteolytic process by two mechanisms. First, particles and metallic ions have been shown to inhibit the osteoblast in terms of its ability to secrete mineralised bone matrix, by reducing calcium deposition, alkaline phosphatase activity and its ability to proliferate. Secondly, particles and metallic ions have been shown to stimulate osteoblasts to produce pro inflammatory mediators in vitro. In vivo, these mediators have the potential to attract pro-inflammatory cells to the peri-prosthetic area and stimulate osteoclasts to absorb bone. Further research is needed to fully define the role of the osteoblast in peri-prosthetic osteolysis and to explore its potential role as a therapeutic target in this condition.

  3. Design of a prosthetic hand with remote actuation.

    Science.gov (United States)

    Scott, Kurt; Perez-Gracia, Alba

    2012-01-01

    One of the main issues of prosthetic hands is to be able to fulfill all the specifications about speed, torque, weight and inertia while placing all the components within the prosthetic hand. This is especially true when full dexterity is required in the prosthesis. In this paper, a new design for a prosthetic hand is presented, which uses remote actuation in order to satisfy most of those requirements. The actuators are to be located in the back of the subject and the transmission is implemented via cables. Other characteristics of this new prosthetic hand include torque limitation and the possibility of switching between underactuated and fully actuated functions.

  4. Dental prosthetic status and prosthetic need of the institutionalized elderly living in geriatric homes in mangalore: a pilot study.

    Science.gov (United States)

    Shenoy, Rekha P; Hegde, Vijaya

    2011-01-01

    Introduction. To promote oral health among the elderly, we need to know their prosthetic status and prosthetic need. Hence, a survey of prosthetic status and need of elderly inmates of old age homes in Mangalore was done. Materials and Methods. A cross-sectional study was undertaken, and 133 subjects aged 60 years and above were examined (54.9% males and 45.1% females). Results. Eighty-eight percent of those examined were fully edentulous, and only 12% had complete dentures; none of the study subjects had partial dentures. Prosthetic status was significantly associated with gender (P = .024), while prosthetic need and gender were not significantly associated (P = .395). Conclusions. A high unmet need for prosthetic care existed among the institutionalized elderly surveyed.

  5. Visual Evoked Potentials to Light Flashes in Captive Rhesus Monkeys: A Study Reflecting Cerebral Cortical Activity and Brain Maturation

    Directory of Open Access Journals (Sweden)

    S.A. Solís-Chávez

    2014-01-01

    Full Text Available Visual evoked potentials (VEPs are useful electrophysiological diagnostic tools for evaluating retinal response of the visual cortex and detecting its functional integrity in humans and animals. To analyze the VEPs and physiologic response of the visual pathway of a random population of captive-bred monkeys of the Macaca mulatta species throughout different physiologic stages after stimulation with stroboscopic light flashes. In this study we used 20 non-human primates (M. mulatta, 10 males and 10 females, divided into five age-dependant cohorts of 2 males and 2 females. Two replicable negative waveforms and one positive were recorded, as reliable indicators of electrical conductivity at specific anatomical nuclei of the visual pathways. Statistically significant differences were primarily observed in group 1 when compared against the remaining groups for the three evaluated waveforms. Waveform morphology characteristically presented steady deviations related to ontogenetic development of the studied population.

  6. Effects of visual deprivation during brain development on expression of AMPA receptor subunits in rat’s hippocampus

    Directory of Open Access Journals (Sweden)

    Sayyed Alireza Talaei

    2015-06-01

    Conclusion: Dark rearing of rats during critical period of brain development changes the relative expression and also arrangement of both AMPA receptor subunits, GluR1 and GluR2 in the hippocampus, age dependently.

  7. Independent processing of visual stimulus changes in ventral and dorsal stream features indexed by an early positive difference in event-related brain potentials.

    Science.gov (United States)

    Kimura, Motohiro; Katayama, Jun'ichi; Murohashi, Harumitsu

    2006-02-01

    In event-related brain potential (ERP) studies of brain activity using a visual S1-S2 matching task, change stimuli elicit a posterior positive component with a latency of 100-200 ms. To elucidate the hierarchical organization of the processing of a visual stimulus change based on multiple stimulus features, ERPs were recorded in 12 participants performing an S1-S2 matching task with stimuli defined by color (mediated by the ventral stream) and motion direction (mediated by the dorsal stream). Each trial consisted of two sequentially presented stimuli (S1-S2), where S2 was either (1) the same as S1 (i.e., no change), (2) different from S1 in color only (color change), (3) different in motion direction only (motion direction change), or (4) different in both color and motion direction (color-motion direction change). These trials were presented in random order with equal probability, and the participants were asked to respond to one of these trials in separate blocks. Relative to the no-change stimulus, the three types of change stimuli elicited posterior positivities. The scalp-topography of change positivities differed according to the feature changed. In addition, the amplitude and scalp-topography of change positivities in response to a conjunction change were the respective sums of those in response to changes in the corresponding single features. These results suggest that the change detection system reflected by the change positivity is separate for each feature dimension, and these operate independently.

  8. Neuro-Prosthetic Implants With Adjustable Electrode Arrays

    Science.gov (United States)

    Whitacre, Jay; DelCastillo, Linda Y.; Mojarradi, Mohammad; Johnson, Travis; West, William; Andersen, Richard

    2006-01-01

    Brushlike arrays of electrodes packaged with application-specific integrated circuits (ASICs) are undergoing development for use as electronic implants especially as neuro-prosthetic devices that might be implanted in brains to detect weak electrical signals generated by neurons. These implants partly resemble the ones reported in Integrated Electrode Arrays for Neuro-Prosthetic Implants (NPO-21198), NASA Tech Briefs, Vol. 27, No. 2 (February 2003), page 48. The basic idea underlying both the present and previously reported implants is that the electrodes would pick up signals from neurons and the ASICs would amplify and otherwise preprocess the signals for monitoring by external equipment. The figure presents a simplified and partly schematic view of an implant according to the present concept. Whereas the electrodes in an implant according to the previously reported concept would be microscopic wires, the electrodes according to the present concept are in the form of microscopic needles. An even more important difference would be that, unlike the previously reported concept, the present concept calls for the inclusion of microelectromechanical actuators for adjusting the depth of penetration of the electrodes into brain tissue. The prototype implant now under construction includes an array of 100 electrodes and corresponding array of electrode contact pads formed on opposite faces of a plate fabricated by techniques that are established in the art of microelectromechanical systems (MEMS). A mixed-signal ASIC under construction at the time of reporting the information for this article will include 100 analog amplifier channels (one amplifier per electrode). On one face of the mixed-signal ASIC there will be a solder-bump/micro-pad array that will have the same pitch as that of the electrode array, and that will be used to make the electrical and mechanical connections between the electrode array and the ASIC. Once the electrode array and the ASIC are soldered

  9. Evaluation of the binding characteristics of [5-{sup 11}C-methoxy]donepezil in the rat brain for in vivo visualization of acetylcholinesterase

    Energy Technology Data Exchange (ETDEWEB)

    Funaki, Yoshihito; Iwata, Ren; Ido, Tatsuo [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Kato, Motohisa; Sakurai, Eiko; Tashiro, Manabu; Yanai, Kazuhiko [Tohoku Univ., Sendai (Japan). Graduate School of Medicine; Sakurai, Eiichi [Tohoku Coll. of Pharmacy, Sendai (Japan)

    2003-02-01

    Donepezil, an acetylcholinesterase (AChE) inhibitor, has not been evaluated for its binding characteristics using a radioactive tracer, although its inhibitory action on AChE has been studied. The aim of this research is to examine whether AChE can be visualized in vivo and in vitro with [{sup 11}C]donepezil. [5-{sup 11}C-methoxy]donepezil was synthesized by O-methylation using [{sup 11}C]methyl triflate. The binding of [{sup 11}C]donepezil to brain homogenates was higher in the brain stem and striatum, and it was lowest in the cerebellum. The in vitro autoradiographic study successfully demonstrated the specific binding of [{sup 11}C]donepezil to AChE in the rat brain. The IC{sub 50} value of binding was approximately 10 nM, which is comparable to the reported value for inhibiting enzyme activity (6 nM). Saturation experiments revealed that the B{sub max} and K{sub d} of [{sup 11}C]donepezil binding in vitro are 65 fmol/mg tissue and 39.8 nM, respectively. In accordance with the in vitro bindings, the in vivo distribution of [{sup 11}C]donepezil was heterogeneous in the rat brain. In the blocking experiments, the heterogeneous distribution disappeared in the presence of a large amount of unlabeled donepezil. These data suggest that [5-{sup 11}C-methoxy]donepezil can be potentially useful to image AChE non-invasively in the human brain by positron emission tomography. (author)

  10. 76 FR 18472 - Medicare Program; Revisions to the Durable Medical Equipment, Prosthetics, Orthotics, and...

    Science.gov (United States)

    2011-04-04

    ... the Act. Prosthetic devices are defined in this section of the Act as ``devices (other than dental... lens.'' Other examples of prosthetic devices include cardiac pacemakers, cochlear implants,...

  11. Comparison of Brain Activation Images Associated with Sexual Arousal Induced by Visual Stimulation and SP6 Acupuncture: fMRI at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Nam Gil [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Han, Jae Bok; Jang, Seong Joo [Dept. of Radiology, Dongshin University, Naju (Korea, Republic of)

    2009-06-15

    This study was performed not only to compare the brain activation regions associated with sexual arousal induced by visual stimulation and SP6 acupuncture, but also to evaluate its differential neuro-anatomical mechanism in healthy women using functional magnetic resonance imaging (fMRI) at 3 Tesla (T). A total of 21 healthy right-handed female volunteers (mean age 22 years, range 19 to 32) underwent fMRI on a 3T MR scanner. The stimulation paradigm for sexual arousal consisted of two alternating periods of rest and activation. It began with a 1-minute rest period, 3 minutes of stimulation with either of an erotic video film or SP6 acupuncture, followed by 1-minute rest. In addition, a comparative study on the brain activation patterns between an acupoint and a shampoint nearby GB37 was performed. The fMRI data were obtained from 20 slices parallel to the AC-PC line on an axial plane, giving a total of 2,000 images. The mean activation maps were constructed and analyzed by using the statistical parametric mapping (SPM99) software. As comparison with the shampoint, the acupoint showed 5 times and 2 times higher activities in the neocortex and limbic system, respectively. Note that brain activation in response to stimulation with the shampoint was not observed in the regions including the HTHL in the diencephalon, GLO and AMYG in the basal ganglia, and SMG in the parietal lobe. In the comparative study of visual stimulation vs. SP6 acupuncture, the mean activation ratio of stimulus was not significantly different to each other in both the neocortex and the limbic system (p < 0.05). The mean activities induced by both stimuli were not significantly different in the neocortex, whereas the acupunctural stimulation showed higher activity in the limbic system (p < 0.05). This study compared the differential brain activation patterns and the neural mechanisms for sexual arousal, which were induced by visual stimulation and SP6 acupuncture by using 3T fMRI. These findings

  12. Visual motion-sensitive neurons in the bumblebee brain convey information about landmarks during a navigational task

    Directory of Open Access Journals (Sweden)

    Marcel eMertes

    2014-09-01

    Full Text Available Bees use visual memories to find the spatial location of previously learnt food sites. Characteristic learning flights help acquiring these memories at newly discovered foraging locations where landmarks - salient objects in the vicinity of the goal location - can play an important role in guiding the animal’s homing behavior. Although behavioral experiments have shown that bees can use a variety of visual cues to distinguish objects as landmarks, the question of how landmark features are encoded by the visual system is still open. Recently, it could be shown that motion cues are sufficient to allow bees localizing their goal using landmarks that can hardly be discriminated from the background texture. Here, we tested the hypothesis that motion sensitive neurons in the bee’s visual pathway provide information about such landmarks during a learning flight and might, thus, play a role for goal localization. We tracked learning flights of free-flying bumblebees (Bombus terrestris in an arena with distinct visual landmarks, reconstructed the visual input during these flights, and replayed ego-perspective movies to tethered bumblebees while recording the activity of direction-selective wide-field neurons in their optic lobe. By comparing neuronal responses during a typical learning flight and targeted modifications of landmark properties in this movie we demonstrate that these objects are indeed represented in the bee’s visual motion pathway. We find that object-induced responses vary little with object texture, which is in agreement with behavioral evidence. These neurons thus convey information about landmark properties that are useful for view-based homing.

  13. Prosthesis preference is related to stride-to-stride fluctuations at the prosthetic ankle

    Directory of Open Access Journals (Sweden)

    Shane R. Wurdeman, CP, MSPO

    2013-08-01

    Full Text Available The purpose of this study was to determine the relationship between stride-to-stride fluctuations and prosthesis preference. Thirteen individuals with unilateral, transtibial amputation consented to participate. Individuals walked on a treadmill for 3 min with their prescribed and an alternate prosthesis. Stride-to-stride fluctuations were quantified with the largest Lyapunov exponent (LyE of each joint flexion/extension time series. The change in the LyE was calculated for each major lower-limb joint for both conditions. Participants indicated preference between the prostheses on a continuous visual analog scale. The change in the LyE was correlated with the degree of preference between the two prostheses at the prosthetic ankle. The change in the LyE of the prosthetic ankle was strongly related to the degree of preference (r = 0.629, p = 0.02. Thus, stride-to-stride fluctuations, quantified by the LyE, are strongly related to the patient’s perception of the prosthesis. As a result, the LyE is the first objective measure to detect changes in gait that relate to the patient’s perception of the prosthesis. The LyE should be further examined as a potentially effective prescriptive and outcome measure in prosthetic rehabilitation.

  14. Neural reactivity to visual food stimuli is reduced in some areas of the brain during evening hours compared to morning hours: an fMRI study in women.

    Science.gov (United States)

    Masterson, Travis D; Kirwan, C Brock; Davidson, Lance E; LeCheminant, James D

    2016-03-01

    The extent that neural responsiveness to visual food stimuli is influenced by time of day is not well examined. Using a crossover design, 15 healthy women were scanned using fMRI while presented with low- and high-energy pictures of food, once in the morning (6:30-8:30 am) and once in the evening (5:00-7:00 pm). Diets were identical on both days of the fMRI scans and were verified using weighed food records. Visual analog scales were used to record subjective perception of hunger and preoccupation with food prior to each fMRI scan. Six areas of the brain showed lower activation in the evening to both high- and low-energy foods, including structures in reward pathways (P foods compared to low-energy foods (P food stimuli tended to produce greater fMRI responses than low-energy food stimuli in specific areas of the brain, regardless of time of day. However, evening scans showed a lower response to both low- and high-energy food pictures in some areas of the brain. Subjectively, participants reported no difference in hunger by time of day (F = 1.84, P = 0.19), but reported they could eat more (F = 4.83, P = 0.04) and were more preoccupied with thoughts of food (F = 5.51, P = 0.03) in the evening compared to the morning. These data underscore the role that time of day may have on neural responses to food stimuli. These results may also have clinical implications for fMRI measurement in order to prevent a time of day bias.

  15. [Reorganization of the system activity of the brain by understanding of the meaning of visually presented texts with increasing completeness of the information].

    Science.gov (United States)

    Tkacheva, L O; Gorbunov, I A; Nasledov, A D

    2015-01-01

    The present paper investigates the study of features of brain activity by the process of change the regimes of information associated with the stages of understanding of the meaning of visually presented texts in adult subjects (n = 148). Researchers have developed an original methodology of step-by-step presentation of the texts. This technology has allowed the researchers "to catch" a psycho-physiological markers of understanding and identify the stages in a temporal sequence of the process of understanding. EEG data was analysed using spectral and non-linear methods. Was highlighted three stages: "before understanding", "understanding" and "after understanding". The study discovered the phenomenon of V- shaped changes to the values of the fractal dimension of EEG. The first stage is characterized by the increasing of the power spectrum of EEG in the high frequency range and increase the value of the fractal dimension of EEG, what probably reflects the process of the generation of ideas and the search of solutions. At the next stage ("understanding") a decrease in the value of the fractal dimension of EEG was registered, and an increase of the power spectrum of the low-frequency range. This seems to reflect the simplification of the invariance of reality to the only valid alternative. The last stage is characterised by the increasing power spectrum of EEG in the high frequency range and increase the value of the fractal dimension of EEG, which can reflect the process of intensification of activity of the brain associated with the verification of the correctness of the decision. The results obtained allow an approach to the understanding of the physiological mechanisms of the reorganization of the system of brain activity in the process.of understanding of the meaning of visually presented texts. This, therefore, outlines the path to the elimination of existing contradictions in the literature relating to the role of high- and low-frequency components of the EEG

  16. The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

    Science.gov (United States)

    Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

    2015-01-01

    Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference.

  17. Contributions of Letter-Speech Sound Learning and Visual Print Tuning to Reading Improvement: Evidence from Brain Potential and Dyslexia Training Studies

    Science.gov (United States)

    Fraga González, Gorka; Žarić, Gojko; Tijms, Jurgen; Bonte, Milene; van der Molen, Maurits W.

    2017-01-01

    We use a neurocognitive perspective to discuss the contribution of learning letter-speech sound (L-SS) associations and visual specialization in the initial phases of reading in dyslexic children. We review findings from associative learning studies on related cognitive skills important for establishing and consolidating L-SS associations. Then we review brain potential studies, including our own, that yielded two markers associated with reading fluency. Here we show that the marker related to visual specialization (N170) predicts word and pseudoword reading fluency in children who received additional practice in the processing of morphological word structure. Conversely, L-SS integration (indexed by mismatch negativity (MMN)) may only remain important when direct orthography to semantic conversion is not possible, such as in pseudoword reading. In addition, the correlation between these two markers supports the notion that multisensory integration facilitates visual specialization. Finally, we review the role of implicit learning and executive functions in audiovisual learning in dyslexia. Implications for remedial research are discussed and suggestions for future studies are presented. PMID:28106790

  18. Contributions of Letter-Speech Sound Learning and Visual Print Tuning to Reading Improvement: Evidence from Brain Potential and Dyslexia Training Studies

    Directory of Open Access Journals (Sweden)

    Gorka Fraga González

    2017-01-01

    Full Text Available We use a neurocognitive perspective to discuss the contribution of learning letter-speech sound (L-SS associations and visual specialization in the initial phases of reading in dyslexic children. We review findings from associative learning studies on related cognitive skills important for establishing and consolidating L-SS associations. Then we review brain potential studies, including our own, that yielded two markers associated with reading fluency. Here we show that the marker related to visual specialization (N170 predicts word and pseudoword reading fluency in children who received additional practice in the processing of morphological word structure. Conversely, L-SS integration (indexed by mismatch negativity (MMN may only remain important when direct orthography to semantic conversion is not possible, such as in pseudoword reading. In addition, the correlation between these two markers supports the notion that multisensory integration facilitates visual specialization. Finally, we review the role of implicit learning and executive functions in audiovisual learning in dyslexia. Implications for remedial research are discussed and suggestions for future studies are presented.

  19. Visualization of the network of primo vessels and primo nodes above the pia mater of the brain and spine of rats by using Alcian blue.

    Science.gov (United States)

    Lee, Ho-Sung; Lee, Byung-Cheon

    2012-10-01

    By spraying and injecting Alcian blue into the lateral ventricle, we were able to visualize the network of the nerve primo vascular system above the pia mater of the brain and spine of rats. Staining these novel structures above the pia mater with 4',6-diamidino-2-phenylindole demonstrated that they coexisted in cellular and extracellular DNA forms. The cellular primo node consisted of many cells surrounded by rod-shaped nuclei while the extracellular primo node had a different morphology from that of a general cell in terms of DNA signals, showing granular DNA in a threadlike network of extracellular DNA. Also, differently from F-actin in general cells, the F-actin in the primo vessel was short and rod-shaped. Light and transmission electron microscopic images of the PN showed that the nerve primo vascular system above the pia mater of the brain and spine was a novel dynamic network, suggesting the coexistence of DNA and extracellular DNA. Based on these data, we suggest that a novel dynamic system with a certain function exists above the pia mater of the central nerve system. We also discuss the potential of this novel network system in the brain and spine as related to acupuncture meridians and neural regeneration.

  20. Injectible bodily prosthetics employing methacrylic copolymer gels

    Science.gov (United States)

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  1. Devising the prosthetic prescription and typical examples.

    Science.gov (United States)

    Passero, Thomas

    2014-02-01

    Limb deficiency has a significant impact on the involved person, with upper limb absence presenting a materially different set of issues than lower limb absence. The primary objectives in fitting a patient with a prosthesis are to enhance their independence in performing daily activities, and to improve their quality of life. For lower limb absence, the primary issues are safety, stability, and the ability to ambulate in a manner consistent with their overall health. The primary objectives in prescribing upper limb prosthetics are function, durability, appearance, comfort, and usability of the device. This article discusses the nuances associated with managing these patients.

  2. Orthopedic Prosthetic Infections: Plastic Surgery Management.

    Science.gov (United States)

    Meaike, Jesse D; Kaufman, Matthew G; Izaddoost, Shayan A

    2016-05-01

    Orthopedic prosthetic infections are potentially devastating complications. Plastic surgeons are frequently consulted to aid in the management of the soft tissue defects that are created by these infections. A review of the existing literature was performed to identify established treatment methods for soft tissue coverage of orthopedic hardware infections for a variety of anatomic locations. The following treatment guidelines and soft tissue reconstructive options were identified as viable options for the management of exposed or infected orthopedic hardware. This review provides descriptions of the various soft tissue reconstructive options available as well as adjunctive treatment methods.

  3. Sonomyography (SMG) control for powered prosthetic hand: a study with normal subjects.

    Science.gov (United States)

    Chen, Xin; Zheng, Yong-Ping; Guo, Jing-Yi; Shi, Jun

    2010-07-01

    Our previous studies have demonstrated that the muscle thickness change detected by ultrasonography during contraction, namely sonomyography (SMG), can be used for functional assessment of skeletal muscles and has the potential for prosthetic control. In this study, we further investigated the feasibility of using one-dimensional SMG (1-D SMG) signal for controlling a powered prosthesis with one degree of freedom. The performance of SMG control in visual pursuit tracking of opening-closure patterns of the prosthesis was evaluated. Nine normal subjects including seven males and two females participated in the experiment. SMG signals were collected from the extensor carpi radialis muscle to control the opening position of the prosthetic hand. The subjects were instructed to perform the wrist extension movement to match the prosthesis response to the target sinusoid and square tracks under different movement rates as accurately as possible. The normalized root mean square (RMS) tracking error between the target track and the degree of the prosthetic hand's opening position, which was measured by an electronic goniometer, was calculated to evaluate the control performance. It was found that the mean RMS tracking errors of SMG control under different movement rates were 12.8 +/- 3.2% (mean +/- SD) and 14.8 +/- 4.6% for sinusoid and square tracks, respectively. Two-way analysis of variance (ANOVA) revealed significant differences in RMS tracking errors among the three movement rates (p = 2.0 x 10(-6)) and between the two target tracks (p = 0.007). The results suggest that SMG signal, based on further improvement, has potential to be an alternative method for prosthetic control.

  4. Abnormal brain activation in neurofibromatosis type 1: a link between visual processing and the default mode network.

    Directory of Open Access Journals (Sweden)

    Inês R Violante

    Full Text Available Neurofibromatosis type 1 (NF1 is one of the most common single gene disorders affecting the human nervous system with a high incidence of cognitive deficits, particularly visuospatial. Nevertheless, neurophysiological alterations in low-level visual processing that could be relevant to explain the cognitive phenotype are poorly understood. Here we used functional magnetic resonance imaging (fMRI to study early cortical visual pathways in children and adults with NF1. We employed two distinct stimulus types differing in contrast and spatial and temporal frequencies to evoke relatively different activation of the magnocellular (M and parvocellular (P pathways. Hemodynamic responses were investigated in retinotopically-defined regions V1, V2 and V3 and then over the acquired cortical volume. Relative to matched control subjects, patients with NF1 showed deficient activation of the low-level visual cortex to both stimulus types. Importantly, this finding was observed for children and adults with NF1, indicating that low-level visual processing deficits do not ameliorate with age. Moreover, only during M-biased stimulation patients with NF1 failed to deactivate or even activated anterior and posterior midline regions of the default mode network. The observation that the magnocellular visual pathway is impaired in NF1 in early visual processing and is specifically associated with a deficient deactivation of the default mode network may provide a neural explanation for high-order cognitive deficits present in NF1, particularly visuospatial and attentional. A link between magnocellular and default mode network processing may generalize to neuropsychiatric disorders where such deficits have been separately identified.

  5. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve holder. 870.3935 Section 870.3935 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold...

  6. Raoultella ornithinolytica: An unusual pathogen for prosthetic joint infection

    Directory of Open Access Journals (Sweden)

    Piseth Seng

    2016-01-01

    Full Text Available We herein report the first case of a prosthetic joint infection caused by Raoultella ornithinolytica in an immunocompetent patient. The clinical outcome was favorable after a two-stage prosthetic exchange and a six-month course of antimicrobial therapy.

  7. Prosthetic valve endocarditis caused by Acinetobacter calcoaceticus subsp. lwoffi.

    OpenAIRE

    Weinberger, I. (Ingeburg); Davidson, E.; Rotenberg, Z; Fuchs, J; Agmon, J

    1987-01-01

    Acinetobacter spp. are uncommon etiologic agents of prosthetic valve endocarditis. Two patients with Acinetobacter calcoaceticus subsp. lwoffi prosthetic valve endocarditis are described. The patients were successfully treated with antibiotics (cefotaxime sodium and gentamicin sulfate); thus, we suggest medical treatment rather than early valve replacement in this particular type of infection.

  8. Prosthetic Rehabilitation in Children: An Alternative Clinical Technique

    Directory of Open Access Journals (Sweden)

    Nádia Carolina Teixeira Marques

    2013-01-01

    Full Text Available Complete and partial removable dentures have been used successfully in numerous patients with oligodontia and/or anodontia. However, there is little information in the literature regarding the principles and guidelines to prosthetic rehabilitation for growing children. This case report describes the management of a young child with oligodontia as well as the treatment planning and the prosthetic rehabilitation technique.

  9. Principles of obstacle avoidance with a transfemoral prosthetic limb

    NARCIS (Netherlands)

    van Keeken, Helco G.; Vrieling, Aline H.; Hof, At L.; Postema, Klaas; Otten, Bert

    2012-01-01

    In this study, conditions that enable a prosthetic knee flexion strategy in transfemoral amputee subjects during obstacle avoidance were investigated. This study explored the hip torque principle and the static ground principle as object avoidance strategies. A prosthetic limb simulator device was u

  10. Use of tenecteplase in recurrent prosthetic valve thrombosis.

    Science.gov (United States)

    Hariram, Vuppaladadhiam; Sharma, Nuthi Prashanthi

    2013-11-01

    Prosthetic valve thrombosis (PVT) is a serious complication of mechanical prosthetic heart valves, the available treatment options for which are either thrombolytic therapy or surgery. In patients who have already received streptokinase to treat a previous episode of PVT, the therapeutic options are limited. Herein, the case is reported of an elderly female patient with a second episode of PVT treated successfully with tenecteplase.

  11. Prosthetic prescription in the Netherlands : an interview with clinical experts

    NARCIS (Netherlands)

    Van Der Linde, H; Geertzen, JHB; Hofstad, CJ; Postema, K

    2004-01-01

    In the process of guideline development for prosthetic prescription in the Netherlands the authors made a study of the daily clinical practice of lower limb prosthetics. Besides the evidence-based knowledge from literature the more implicit knowledge from clinical experts is of importance for guidel

  12. Stiffness and hysteresis properties of some prosthetic feet

    NARCIS (Netherlands)

    Jaarsveld, van H.W.L.; Grootenboer, H.J.; Vries, de J.; Koopman, H.F.J.M.

    1990-01-01

    A prosthetic foot is an important element of a prosthesis, although it is not always fully recognized that the properties of the foot, along with the prosthetic knee joint and the socket, are in part responsible for the stability and metabolic energy cost during walking. The stiffness and the hyst

  13. Cobalt-57 as a SPET tracer in the visualization of ischaemic brain damage in patients with middle cerebral artery stroke

    NARCIS (Netherlands)

    Stevens, H; Knollema, S; Piers, DA; Van de Wiele, C; Jansen, HML; De Jager, AEJ; De Reuck, J; Dierckx, RA; Korf, J

    1998-01-01

    In PET studies we have shown the usefulness of cobalt radionuclides for the visualization and quantification of ischaemic damage in stroke. In the present study, we explored Co-57(2+) as a SPET tracer. Uptake of radioactivity was estimated by using a cobalt enhancement ratio defined as the ratio of

  14. Steady-state motion visual evoked potentials produced by oscillating Newton's rings: implications for brain-computer interfaces.

    Directory of Open Access Journals (Sweden)

    Jun Xie

    Full Text Available In this study, we utilize a special visual stimulation protocol, called motion reversal, to present a novel steady-state motion visual evoked potential (SSMVEP-based BCI paradigm that relied on human perception of motions oscillated in two opposite directions. Four Newton's rings with the oscillating expansion and contraction motions served as visual stimulators to elicit subjects' SSMVEPs. And four motion reversal frequencies of 8.1, 9.8, 12.25 and 14 Hz were tested. According to Canonical Correlation Analysis (CCA, the offline accuracy and ITR (mean ± standard deviation over six healthy subjects were 86.56 ± 9.63% and 15.93 ± 3.83 bits/min, respectively. All subjects except one exceeded the level of 80% mean accuracy. Circular Hotelling's T-Squared test (T2 circ also demonstrated that most subjects exhibited significantly strong stimulus-locked SSMVEP responses. The results of declining exponential fittings exhibited low-adaptation characteristics over the 100-s stimulation sequences in most experimental conditions. Taken together, these results suggest that the proposed paradigm can provide comparable performance with low-adaptation characteristic and less visual discomfort for BCI applications.

  15. Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Skakkebæk, Anne; Bojesen, Anders

    2016-01-01

    with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups...

  16. Real-time visualization and characterization of liposomal delivery into the monkey brain by magnetic resonance imaging.

    Science.gov (United States)

    Krauze, Michal T; Mcknight, Tracy R; Yamashita, Yoji; Bringas, John; Noble, Charles O; Saito, Ryuta; Geletneky, Karsten; Forsayeth, John; Berger, Mitchel S; Jackson, Pamela; Park, John W; Bankiewicz, Krystof S

    2005-12-01

    Liposomes loaded with Gadoteridol, in combination with convection-enhanced delivery (CED), offer an excellent option to monitor CNS delivery of therapeutic compounds with MRI. In previous studies, we investigated possible clinical applications of liposomes to the treatment of brain tumors. In this study, up to 700 microl of Gadoteridol/rhodamine-loaded liposomes were distributed in putamen, corona radiata and brainstem of non-human primates. Distribution was monitored by real-time MRI throughout infusion procedures and allowed accurate calculation of volume of distribution within anatomical structures. We found that different regions of the brain gave various volumes of distribution when infused with the same volume of liposome. Based on these findings, distinct distribution pathways within infused structures can be predicted. This work underlines the importance of monitoring drug delivery to CNS and enables accurate delivery of drug-loaded liposomes to specific brain regions with a standard MRI procedure. Findings presented in this manuscript may allow for modeling of parameters used for direct delivery of therapeutics into various regions of the brain.

  17. Aberrant Early Visual Neural Activity and Brain-Behavior Relationships in Anorexia Nervosa and Body Dysmorphic Disorder

    Directory of Open Access Journals (Sweden)

    Wei eLi

    2015-06-01

    Full Text Available Background:Body dysmorphic disorder (BDD and anorexia nervosa (AN share the clinical symptom of disturbed body image, which may be a function of perceptual distortions. Previous studies suggest visual or visuospatial processing abnormalities may be contributory, but have been unable to discern whether these occur early or late in the visual processing stream. We used electroencephalography (EEG and visual event related potentials (ERP to investigate early perceptual neural activity associated with processing visual stimuli.Methods:We performed EEG on 20 AN, 20 BDD, 20 healthy controls, all unmedicated. In order to probe configural/holistic and detailed processing, participants viewed photographs of faces and houses that were unaltered or filtered to low or high spatial frequencies, respectively. We calculated the early ERP components P100 and N170, and compared amplitudes and latencies among groups.Results:P100 amplitudes were smaller in AN than BDD and healthy controls, regardless of spatial frequency or stimulus type (faces or houses. Similarly, N170 latencies were longer in AN than healthy controls, regardless of spatial frequency or stimulus type, with a similar pattern in BDD at trend level significance. N170 amplitudes were smaller in AN than controls for high and normal spatial frequency images, and smaller in BDD than controls for normal spatial frequency images, regardless of stimulus type. Poor insight correlated with lower N170 amplitudes for normal and low spatial frequency faces in the BDD group.Conclusions:Individuals with AN exhibit abnormal early visual system activity, consistent with reduced configural processing and enhanced detailed processing. This is evident regardless of whether the stimuli are appearance- or non appearance-related, and thus may be a reflection of general, early perceptual abnormalities. As N170 amplitude could be a marker of structural encoding of faces, lower values may be associated with perceptual dis

  18. The Prosthetic Workflow in the Digital Era

    Directory of Open Access Journals (Sweden)

    Lidia Tordiglione

    2016-01-01

    Full Text Available The purpose of this retrospective study was to clinically evaluate the benefits of adopting a full digital workflow for the implementation of fixed prosthetic restorations on natural teeth. To evaluate the effectiveness of these protocols, treatment plans were drawn up for 15 patients requiring rehabilitation of one or more natural teeth. All the dental impressions were taken using a Planmeca PlanScan® (Planmeca OY, Helsinki, Finland intraoral scanner, which provided digital casts on which the restorations were digitally designed using Exocad® (Exocad GmbH, Germany, 2010 software and fabricated by CAM processing on 5-axis milling machines. A total of 28 single crowns were made from monolithic zirconia, 12 vestibular veneers from lithium disilicate, and 4 three-quarter vestibular veneers with palatal extension. While the restorations were applied, the authors could clinically appreciate the excellent match between the digitally produced prosthetic design and the cemented prostheses, which never required any occlusal or proximal adjustment. Out of all the restorations applied, only one exhibited premature failure and was replaced with no other complications or need for further scanning. From the clinical experience gained using a full digital workflow, the authors can confirm that these work processes enable the fabrication of clinically reliable restorations, with all the benefits that digital methods bring to the dentist, the dental laboratory, and the patient.

  19. The Prosthetic Workflow in the Digital Era

    Science.gov (United States)

    De Franco, Michele; Bosetti, Giovanni

    2016-01-01

    The purpose of this retrospective study was to clinically evaluate the benefits of adopting a full digital workflow for the implementation of fixed prosthetic restorations on natural teeth. To evaluate the effectiveness of these protocols, treatment plans were drawn up for 15 patients requiring rehabilitation of one or more natural teeth. All the dental impressions were taken using a Planmeca PlanScan® (Planmeca OY, Helsinki, Finland) intraoral scanner, which provided digital casts on which the restorations were digitally designed using Exocad® (Exocad GmbH, Germany, 2010) software and fabricated by CAM processing on 5-axis milling machines. A total of 28 single crowns were made from monolithic zirconia, 12 vestibular veneers from lithium disilicate, and 4 three-quarter vestibular veneers with palatal extension. While the restorations were applied, the authors could clinically appreciate the excellent match between the digitally produced prosthetic design and the cemented prostheses, which never required any occlusal or proximal adjustment. Out of all the restorations applied, only one exhibited premature failure and was replaced with no other complications or need for further scanning. From the clinical experience gained using a full digital workflow, the authors can confirm that these work processes enable the fabrication of clinically reliable restorations, with all the benefits that digital methods bring to the dentist, the dental laboratory, and the patient. PMID:27829834

  20. Is the prosthetic homologue necessary for embodiment?

    Directory of Open Access Journals (Sweden)

    Chelsea Dornfeld

    2016-12-01

    Full Text Available Embodiment is the process by which patients with limb loss come to accept their peripheral device as a natural extension of self. However, there is little guidance as to how exacting the prosthesis must be in order for embodiment to take place: is it necessary for the prosthetic hand to look just like the absent hand? Here, we describe a protocol for testing whether an individual would select a hand that looks like their own from among a selection of 5 hands, and whether the hand selection (regardless of homology is consistent across multiple exposures to the same (but reordered set of candidate hands. Pilot results using healthy volunteers reveals that hand selection is only modestly consistent, and that selection of the prosthetic homologue is atypical (61 of 192 total exposures. Our protocol can be executed in minutes, and makes use of readily available equipment and softwares. We present both a face-to-face and a virtual protocol, for maximum flexibility of implementation.

  1. The use of underactuation in prosthetic grasping

    Directory of Open Access Journals (Sweden)

    P. J. Kyberd

    2011-02-01

    Full Text Available Underactuation as a method of driving prosthetic hands has a long history. The pragmatic requirements of such a device to be light enough to be worn and used regularly have meant that any multi degree of freedom prosthetic hand must have fewer actuators than the usable degrees of freedom. Aesthetics ensures that while the hand needs five fingers, five actuators have considerable mass, and only in recent years has it even been possible to construct a practical anthropomorphic hand with five motors. Thus there is an important trade off as to which fingers are driven, and which joints on which fingers are actuated, and how the forces are distributed to create a functional device. This paper outlines some of the historical solutions created for this problem and includes those designs of recent years that are now beginning to be used in the commercial environment.

    This paper was presented at the IFToMM/ASME International Workshop on Underactuated Grasping (UG2010, 19 August 2010, Montréal, Canada.

  2. Is the Prosthetic Homologue Necessary for Embodiment?

    Science.gov (United States)

    Dornfeld, Chelsea; Swanston, Michelle; Cassella, Joseph; Beasley, Casey; Green, Jacob; Moshayev, Yonatan; Wininger, Michael

    2016-01-01

    Embodiment is the process by which patients with limb loss come to accept their peripheral device as a natural extension of self. However, there is little guidance as to how exacting the prosthesis must be in order for embodiment to take place: is it necessary for the prosthetic hand to look just like the absent hand? Here, we describe a protocol for testing whether an individual would select a hand that looks like their own from among a selection of five hands, and whether the hand selection (regardless of homology) is consistent across multiple exposures to the same (but reordered) set of candidate hands. Pilot results using healthy volunteers reveals that hand selection is only modestly consistent, and that selection of the prosthetic homologue is atypical (61 of 192 total exposures). Our protocol can be executed in minutes, and makes use of readily available equipment and softwares. We present both a face-to-face and a virtual protocol, for maximum flexibility of implementation. PMID:28066228

  3. Surgical and prosthetic treatment for microphthalmia syndromes.

    Science.gov (United States)

    Wavreille, O; François Fiquet, C; Abdelwahab, O; Laumonier, E; Wolber, A; Guerreschi, P; Pellerin, P

    2013-03-01

    Our aim was to evaluate the long-term outcomes of prosthetic treatment and orbital expansion in the management of microphthalmia syndromes. We did a retrospective single-centre study of all cases of microphthalmia treated between 1989 and 2010. The patients were divided into three groups: isolated microphthalmia, microphthalmia associated with micro-orbitism, and complex microphthalmia syndrome. To evaluate the results a score was computed for each patient by assessing the length of the palpebral fissure, the depth of the conjunctival fornix, and local complications together with an evaluation of the satisfaction of patients and their families. Forty-four children were included (27 boys and 17 girls). Twenty-seven had unilateral microphthalmia (61%) and 17 bilateral microphthalmia (39%). Twelve patients were lost to follow up. The mean duration of follow-up was 12 years (range 4-21). Management involved an ocular conformer in only 31 patients (71%). The treatment was deemed satisfactory in all except 10 children. Surgical treatment with orbital expansion permitted good symmetry of the orbital cavities with a final mean difference of 9% (range 3-17) compared with the initial 16.8% (range 13.6-20.3). The prosthetic treatment gives satisfactory results. Despite limited indications and difficult follow-up, our experience emphasises the value of surgical treatment for severe micro-orbitism.

  4. Carbon-11 pb-12: an attempt to visualize the dopamine d{sub 4} receptor in the primate brain with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Langer, Oliver E-mail: oliver.langer@psyk.ks.se; Halldin, Christer; Chou Yuanhwa; Sandell, Johan; Swahn, Carl-Gunnar; Naagren, Kjell; Perrone, Roberto; Berardi, Francesco; Leopoldo, Marcello; Farde, Lars

    2000-11-01

    [{sup 11}C]PB-12 is not suitable to visualize the D{sub 4}R in the primate brain with PET.

  5. Exercise increases blood flow to locomotor, vestibular, cardiorespiratory and visual regions of the brain in miniature swine

    Science.gov (United States)

    Delp, M. D.; Armstrong, R. B.; Godfrey, D. A.; Laughlin, M. H.; Ross, C. D.; Wilkerson, M. K.

    2001-01-01

    1. The purpose of these experiments was to use radiolabelled microspheres to measure blood flow distribution within the brain, and in particular to areas associated with motor function, maintenance of equilibrium, cardiorespiratory control, vision, hearing and smell, at rest and during exercise in miniature swine. Exercise consisted of steady-state treadmill running at intensities eliciting 70 and 100 % maximal oxygen consumption (V(O(2),max)). 2. Mean arterial pressure was elevated by 17 and 26 % above that at rest during exercise at 70 and 100 % V(O(2),max), respectively. 3. Mean brain blood flow increased 24 and 25 % at 70 and 100 % V(O(2),max), respectively. Blood flow was not locally elevated to cortical regions associated with motor and somatosensory functions during exercise, but was increased to several subcortical areas that are involved in the control of locomotion. 4. Exercise elevated perfusion and diminished vascular resistance in several regions of the brain related to the maintenance of equilibrium (vestibular nuclear area, cerebellar ventral vermis and floccular lobe), cardiorespiratory control (medulla and pons), and vision (dorsal occipital cortex, superior colliculi and lateral geniculate body). Conversely, blood flow to regions related to hearing (cochlear nuclei, inferior colliculi and temporal cortex) and smell (olfactory bulbs and rhinencephalon) were unaltered by exercise and associated with increases in vascular resistance. 5. The data indicate that blood flow increases as a function of exercise intensity to several areas of the brain associated with integrating sensory input and motor output (anterior and dorsal cerebellar vermis) and the maintenance of equilibrium (vestibular nuclei). Additionally, there was an intensity-dependent decrease of vascular resistance in the dorsal cerebellar vermis.

  6. Comparison of Histological Techniques to Visualize Iron in Paraffin-embedded Brain Tissue of Patients with Alzheimer’s Disease

    OpenAIRE

    van Duijn, Sara; Rob J A Nabuurs; van Duinen, Sjoerd G.; Natté, Remco

    2013-01-01

    Better knowledge of the distribution of iron in the brains of Alzheimer’s disease (AD) patients may facilitate the development of an in vivo magnetic resonance (MR) marker for AD and may cast light on the role of this potentially toxic molecule in the pathogenesis of AD. Several histological iron staining techniques have been used in the past but they have not been systematically tested for sensitivity and specificity. This article compares three histochemical techniques and ferritin immunohi...

  7. Glucose-induced inhibition of the appetitive brain response to visual food cues in polycystic ovary syndrome patients.

    Science.gov (United States)

    Van Vugt, Dean A; Krzemien, Alicja; Alsaadi, Hanin; Frank, Tamar C; Reid, Robert L

    2014-04-16

    We postulate that insulin regulation of food intake is compromised when insulin resistance is present. In order to investigate the effect of insulin sensitivity on appetitive brain responses, we conducted functional magnetic resonance imaging studies in a group of women diagnosed with polycystic ovary syndrome (PCOS) in which insulin sensitivity ranged from normal to resistant. Subjects (n=19) were imaged while viewing pictures of high calorie (HC) foods and low calorie (LC) foods after ingesting either 75 g glucose or an equivalent volume of water. The insulin sensitive group showed reduced blood oxygen level dependent (BOLD) signal in response to food pictures following glucose ingestion in numerous corticolimbic brain regions, whereas the insulin resistant group did not. There was a significant interaction between insulin sensitivity (sensitive vs resistant) and condition (water vs glucose). The largest clusters identified included the left insula, bilateral limbic/parahippocampal gyrus/culmen/midbrain, bilateral limbic lobe/precuneus, and left superior/mid temporal gyrus/parietal for HC and LC stimuli combined, the left parahippocampal gyrus/fusiform/pulvinar/midbrain for HC pictures, and the left superior/mid temporal gyrus/parietal and middle/inferior frontal gyrus/orbitofrontal cortex for LC pictures. Furthermore, BOLD signal in the anterior cingulate, medial frontal gyrus, posterior cingulate/precuneus, and parietal cortex during a glucose challenge correlated negatively with insulin sensitivity. We conclude the PCOS women with insulin resistance have an impaired brain response to a glucose challenge. The inability of postprandial hyperinsulinemia to inhibit brain responsiveness to food cues in insulin resistant subjects may lead to greater non-homeostatic eating.

  8. 78 FR 48941 - Advisory Committee on Prosthetics and Special-Disabilities Programs, Notice of Meeting

    Science.gov (United States)

    2013-08-12

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs, Notice of Meeting The..., that a meeting of the Federal Advisory Committee on Prosthetics and Special-Disabilities Programs will... Veterans Affairs on VA's prosthetics programs designed to provide state-of-the- art prosthetics and...

  9. 77 FR 65609 - Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2012-10-29

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting The..., that a meeting of the Federal Advisory Committee on Prosthetics and Special-Disabilities Programs will... Veterans Affairs on VA's prosthetics programs designed to provide state-of-the- art prosthetics and...

  10. 76 FR 21107 - Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2011-04-14

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting The...) that a meeting of the Advisory Committee on Prosthetics and Special-Disabilities Programs will be held... Veterans Affairs on VA's prosthetics programs designed to provide state-of-the art prosthetics and...

  11. 78 FR 69176 - Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2013-11-18

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting The..., that a meeting of the Federal Advisory Committee on Prosthetics and Special-Disabilities Programs will... Veterans Affairs on VA's prosthetics programs designed to provide state-of-the- art prosthetics and...

  12. Predicting prosthetic prescription after major lower-limb amputation

    Directory of Open Access Journals (Sweden)

    Linda Resnik, PT, PhD, OCS

    2015-09-01

    Full Text Available We describe prosthetic limb prescription in the first year following lower-limb amputation and examine the relationship between amputation level, geographic region, and prosthetic prescription. We analyzed 2005 to 2010 Department of Veterans Affairs (VA Inpatient and Medical Encounters SAS data sets, Vital Status death data, and National Prosthetic Patient Database data for 9,994 Veterans who underwent lower-limb amputation at a VA hospital. Descriptive statistics and bivariates were examined. Cox proportional hazard models identified factors associated with prosthetic prescription. Analyses showed that amputation level was associated with prosthetic prescription. The hazard ratios (HRs were 1.41 for ankle amputation and 0.46 for transfemoral amputation compared with transtibial amputation. HRs for geographic region were Northeast = 1.49, Upper Midwest = 1.26, and West = 1.39 compared with the South (p < 0.001. African American race, longer length of hospital stay, older age, congestive heart failure, paralysis, other neurological disease, renal failure, and admission from a nursing facility were negatively associated with prosthetic prescription. Being married was positively associated. After adjusting for patient characteristics, people with ankle amputation were most likely to be prescribed a prosthesis and people with transfemoral amputation were least likely. Geographic variation in prosthetic prescription exists in the VA and further research is needed to explain why.

  13. A COMPARATIVE STUDY ON THE EFFECTS OF THE POLYMER PROSTHETIC BASE PRESSURE OVER THE PROSTHETIC FIELD

    Directory of Open Access Journals (Sweden)

    A.T. Cigu

    2016-04-01

    Full Text Available Partially mobile polymeric prostheses constitute absolutely necessary therapeutical means in all forms of partial edentations. As known, polymeric partial prostheses constitute temporary solutions for the treatment of edentaton states. Nowadays, this treatment includes traditional acrylic prostheses, as well as elastic prostheses made of different material systems. Such a system is Valplast, which uses a polyamide for the realization of the prosthetic base. Both the rigid and the elastic materials are nowadays under debate, different – positive or negative – opinions being uttered in relation with their utilization. The scope of the present study is to support the intensive application of the elastic materials. Extremely important is the identification of the intrinsic qualities of the materials influencing the behaviour in the oral cavity, especially the effects of pressure upon the biological structures of the prosthetic field.

  14. 'Who is the ideal candidate?': decisions and issues relating to visual neuroprosthesis development, patient testing and neuroplasticity

    Science.gov (United States)

    Merabet, Lotfi B.; Rizzo, Joseph F., III; Pascual-Leone, Alvaro; Fernandez, Eduardo

    2007-03-01

    Appropriate delivery of electrical stimulation to intact visual structures can evoke patterned sensations of light in individuals who have been blind for many years. This pivotal finding has lent credibility to the concept of restoring functional vision by artificial means. As numerous groups worldwide pursue human clinical testing with visual prosthetic devices, it is becoming increasingly clear that there remains a considerable gap between the challenges of prosthetic device development and the rehabilitative strategies needed to implement this new technology in patients. An important area of future work will be the development of appropriate pre- and post-implantation measures of performance and establishing candidate selection criteria in order to quantify technical advances, guide future device design and optimize therapeutic success. We propose that the selection of an 'ideal' candidate should also be considered within the context of the variable neuroplastic changes that follow vision loss. Specifically, an understanding of the adaptive and compensatory changes that occur within the brain could assist in guiding the development of post-implantation rehabilitative strategies and optimize behavioral outcomes.

  15. Brain-derived neurotrophic factor-mediated retrograde signaling required for the induction of long-term potentiation at inhibitory synapses of visual cortical pyramidal neurons.

    Science.gov (United States)

    Inagaki, Tsuyoshi; Begum, Tahamina; Reza, Faruque; Horibe, Shoko; Inaba, Mie; Yoshimura, Yumiko; Komatsu, Yukio

    2008-06-01

    High-frequency stimulation (HFS) induces long-term potentiation (LTP) at inhibitory synapses of layer 5 pyramidal neurons in developing rat visual cortex. This LTP requires postsynaptic Ca2+ rise for induction, while the maintenance mechanism is present at the presynaptic site, suggesting presynaptic LTP expression and the necessity of retrograde signaling. We investigated whether the supposed signal is mediated by brain-derived neurotrophic factor (BDNF), which is expressed in pyramidal neurons but not inhibitory interneurons. LTP did not occur when HFS was applied in the presence of the Trk receptor tyrosine kinase inhibitor K252a in the perfusion medium. HFS produced LTP when bath application of K252a was started after HFS or when K252a was loaded into postsynaptic cells. LTP did not occur in the presence of TrkB-IgG scavenging BDNF or function-blocking anti-BDNF antibody in the medium. In cells loaded with the Ca2+ chelator BAPTA, the addition of BDNF to the medium enabled HFS to induce LTP without affecting baseline synaptic transmission. These results suggest that BDNF released from postsynaptic cells activates presynaptic TrkB, leading to LTP. Because BDNF, expressed activity dependently, regulates the maturation of cortical inhibition, inhibitory LTP may contribute to this developmental process, and hence experience-dependent functional maturation of visual cortex.

  16. Genitourinary Prosthetics: A Primer for the Non-urologic Surgeon.

    Science.gov (United States)

    Lavien, Garjae; Zaid, Uwais; Peterson, Andrew C

    2016-06-01

    Genitourinary prosthetics are used for correction of functional deficits and to improve the quality of lives of affected patients. General surgeons must evaluate patients scheduled for nonurologic surgery with urologic devices that can impact their perioperative management. Lack of recognition of these prosthetics preoperatively can lead to unnecessary morbidity for the patient and have legal implications for the surgeon. Close consultation with a urologist may avoid common complications associated with these devices and allows for surgical assistance when operative misadventures do occur. This article reviews 3 common urologic prosthetics: testicular prosthesis, artificial urinary sphincter, and penile prosthesis.

  17. Gait analysis in lower-limb amputation and prosthetic rehabilitation.

    Science.gov (United States)

    Esquenazi, Alberto

    2014-02-01

    Gait analysis combined with sound clinical judgment plays an important role in elucidating the factors involved in the pathologic prosthetic gait and the selection and effects of available interventions to optimize it. Detailed clinical evaluation of walking contributes to the analysis of the prosthetic gait, but evaluation in the gait laboratory using kinetic and kinematic data is often necessary to quantify and identify the particular contributions of the variables impacting the gait with confidence and assess the results of such intervention. The same approach can be considered when selecting prosthetic components and assessing leg length in this patient population.

  18. Comparison of tactile, auditory and visual modality for brain-computer interface use: A case study with a patient in the locked-in state

    Directory of Open Access Journals (Sweden)

    Tobias eKaufmann

    2013-07-01

    Full Text Available This paper describes a case study with a patient in the classic locked-in state, who currently has no means of independent communication. Following a user-centered approach, we investigated event-related potentials elicited in different modalities for use in brain-computer interface systems. Such systems could provide her with an alternative communication channel. To investigate the most viable modality for achieving BCI based communication, classic oddball paradigms (1 rare and 1 frequent stimulus, ratio 1:5 in the visual, auditory and tactile modality were conducted (2 runs per modality. Classifiers were built on one run and tested offline on another run (and vice versa. In these paradigms, the tactile modality was clearly superior to other modalities, displaying high offline accuracy even when classification was performed on single trials only. Consequently, we tested the tactile paradigm online and the patient successfully selected targets without any error. Furthermore, we investigated use of the visual or tactile modality for different BCI systems with more than two selection options. In the visual modality, several BCI paradigms were tested offline. Neither matrix-based nor so-called gaze-independent paradigms constituted a means of control. These results may thus question the gaze-independence of current gaze-independent approaches to BCI. A tactile four-choice BCI resulted in high offline classification accuracies. Yet, online use raised various issues. Although performance was clearly above chance, practical daily life use appeared unlikely when compared to other communication approaches (e.g. partner scanning. Our results emphasize the need for user-centered design in BCI development including identification of the best stimulus modality for a particular user. Finally, the paper discusses feasibility of EEG-based BCI systems for patients in classic locked-in state and compares BCI to other AT solutions that we also tested during the

  19. The Effectiveness of Visual Short-Time Neurofeedback on Brain Activity and Clinical Characteristics in Alcohol Use Disorders: Practical Issues and Results.

    Science.gov (United States)

    Lackner, Nina; Unterrainer, Human F; Skliris, Dimitris; Wood, Guilherme; Wallner-Liebmann, Sandra J; Neuper, Christa; Gruzelier, John H

    2016-07-01

    The present study was carried out to examine the efficacy of alpha/theta neurofeedback (NF) with a new visual paradigm in a cohort of alcohol use disordered (AUD) patients (n = 25) treated in an Austrian therapeutic community center. The experimental study design focused on changes in absolute and relative resting EEG band power as well as in clinical variables, including depression (Beck Depresion Inventory [BDI-V]), psychiatric symptoms (Brief Symptom Inventory [BSI], coping (Freiburg Questionnaire on Coping with Illness [FKV-lis]), psychotherapy motivation (Therapy Motivation Questionnaire [FPTM-23]), sense of coherence (Sense of Coherence Scale [SOC-13]), posttraumatic growth (Posttraumatic Growth Inventory [PPR]), and alcohol cravings (Alcohol Craving Questionnaire [ACQ]). For measuring training effects, participants were randomly allocated to 2 groups: an experimental group (EG, n = 13) and a control group (CG, n = 12). Patients in EG received 12 sessions of visual NF training over a period of 6 weeks to enhance alpha (8-12 Hz) and theta (4-7 Hz) frequency band power in addition to the standard treatment program of the rehabilitation center. Participants in CG received no additional NF intervention. The multivariate analysis of covariance (MANCOVA) showed a change by trend in absolute alpha and theta power in the EG. Even though no MANCOVA effects were found in the clinical scales, AUD patients reported increasing control of their brain activity during the course of NF. However, changes in several clinical scales (BDI-V, BSI, FKV-lis, PPR) from pre- to posttest were observed only in the EG contrary to the CG. The findings of this pilot study provide first evidence for the practicality and effectiveness of visual short-term NF as an additive intervention in the therapeutic community.

  20. [Complex partial status epilepticus with recurrent episodes of complex visual hallucinations: study by using 123I-IMP-SPECT, brain MRI and EEG].

    Science.gov (United States)

    Sakai, Toshiyuki; Kondo, Masahide; Tomimoto, Hidekazu

    2015-01-01

    We report a 72-year-old woman with complex partial status epilepticus who showed recurrent episodes of complex visual hallucinations (CVH). Brain diffusion-weighted magnetic resonance images revealed gyriform cortical hyperintensity in the right parietal, occipital and temporal lobes, and brain magnetic resonance angiograhy revealed a hyperintensity in the right dilated middle cerebral artery during ictal period. Ictal N-isopropyl-p-(iodine-123)-iodoamphetamine single photon emission computed tomography (123I-IMP-SPECT) with three-dimensional stereotactic surface projection (3D-SSP) 14 days after the onset of the first CVH revealed hyperperfusion in the right latero-inferior occipito-temporal region with relation to motion. CVH spontaneously subsided 17 days after the onset of the first CVH. CVH recurred one year after the first CVH. Ictal 123I-IMP-SPECT with 3D-SSP revealed marked hyperperfusion in the right lateral parietal region probably with relation to face and figure hallucinations. Ictal scalp EEGs revealed rhythmic polyspikes at 12 Hz with high amplitude (100-200 μV) in bilateral posterior occipital and temporal region with the right side dominance for 20 seconds and more in several occasions. Interictal 123I-IMP-SPECT with 3D-SSP 28 days after recurrence of CVH revealed marked hypoperfusion in the right lateral parietal region, and recovery of hypoperfusion in the right latero-inferior occipito-temporal region. These findings suggest that ictal CVH might be induced by the spread of epileptic discharges from the right parieto-occipito-temporal region with the old brain contusion (epileptogenic region) to the right latero-inferior occipito-temporal region and the right lateral parietal region (symptomatogenic regions).

  1. Autoradiographic visualization of angiotensin-converting enzyme in rat brain with (/sup 3/H)captopril: localization to a striatonigral pathway

    Energy Technology Data Exchange (ETDEWEB)

    Strittmatter, S.M.; Lo, M.M.S.; Javitch, J.A.; Snyder, S.H.

    1984-03-01

    The authors have visualized angiotensin-converting enzyme (ACE; dipeptidyl carboxypeptidase, peptidylpeptide hydrolase, EC 3.4.15.1) in rat brain by in vitro (/sup 3/H)captopril autoradiography. (/sup 3/H)Captopril binding to brain slices displays a high affinity (K/sub d/ = 1.8 x 10/sup -9/ M) and a pharmacological profile similar to that of ACE activity. Very high densities of (/sup 3/H)captopril binding were found in the choroid plexus and the subfornical organ. High densities were present in the caudate putamen and substantia nigra, zona reticulata. Moderate levels were found in the entopeduncular nucleus, globus pallidus, and median eminence of the hypothalamus. Lower levels were detectable in the supraoptic and paraventricular nuclei of the hypothalamus, the media habenula, the median preoptic area, and the locus coeruleus. Injection of ibotenic acid or colchicine into the caudate putamen decreased (/sup 3/H)captopril-associated autoradiographic grains by 85% in the ipsilateral caudate putamen and by > 50% in the ipsilateral substantia nigra. Thus, ACE in the substantia nigra is located on presynaptic terminals of axons originating from the caudate putamen, and ACE in the caudate putamen is situated in neuronal perikarya or at the terminals of striatal interneurons. The lack of effect of similar injections into the substantia nigra confirmed that the caudate putamen injections did not cause trans-synaptic changes. The presence of (/sup 3/H)captopril binding is consistent with an ACE-mediated production of angiotensin II in some brain regions. Although (/sup 3/H)captopril autoradiography reveals ACE in a striatonigral pathway, there is no evidence for angiotensin II involvement in such a neuronal pathway. 26 references, 4 figures, 2 tables.

  2. Maxillofacial prosthetic materials- an inclination towards silicones.

    Science.gov (United States)

    Mitra, Aparajita; Choudhary, Sunita; Garg, Hemlata; H G, Jagadeesh

    2014-12-01

    There have been constant searches and researches which are taking place in the field of dental materials to best suit the ideal selection criteria to satisfy the functionality, biocompatibility, aesthetics as well as the durability as a maxillofacial material. Among all the different materials, Silicone is the most popularly used, but still studies are carried out to overcome their weaknesses and to come out with a material which can be labeled as the "ideal maxillofacial prosthetic material". This article comprises the materials which were and are in use and the reason for their unpopularity. It also gives us a scope to understand the major fields where the materials lack and thus needs improvement to render an individual with the best maxillo-facial prosthesis.

  3. [Improving the speech with a prosthetic construction].

    Science.gov (United States)

    Stalpers, M J; Engelen, M; van der Stappen, J A A M; Weijs, W L J; Takes, R P; van Heumen, C C M

    2016-03-01

    A 12-year-old boy had problems with his speech due to a defect in the soft palate. This defect was caused by the surgical removal of a synovial sarcoma. Testing with a nasometer revealed hypernasality above normal values. Given the size and severity of the defect in the soft palate, the possibility of improving the speech with speech therapy was limited. At a centre for special dentistry an attempt was made with a prosthetic construction to improve the performance of the palate and, in that way, the speech. This construction consisted of a denture with an obturator attached to it. With it, an effective closure of the palate could be achieved. New measurements with acoustic nasometry showed scores within the normal values. The nasality in the speech largely disappeared. The obturator is an effective and relatively easy solution for palatal insufficiency resulting from surgical resection. Intrusive reconstructive surgery can be avoided in this way.

  4. Upper limb prosthetic use in Slovenia.

    Science.gov (United States)

    Burger, H; Marincek, C

    1994-04-01

    The article deals with the use of different types of upper limb prostheses in Slovenia. Four hundred and fourteen upper limb amputees were sent a questionnaire on the type of their prosthesis, its use and reasons for non-use, respectively. The replies were subject to statistical analysis. Most of the questioned upper limb amputees (70%) wear a prosthesis only for cosmesis. The use of a prosthesis depends on the level of upper limb amputation, loss of the dominant hand, and time from amputation. Prosthetic success appears to be unrelated to age at the time of amputation and the rehabilitation programme. The most frequent reason for not wearing a prosthesis is heat and consequent sweating of the stump. More than a third of amputees are dissatisfied with their prostheses.

  5. A Miniature Force Sensor for Prosthetic Hands

    Science.gov (United States)

    Platt, Robert; Chu, Mars; Diftler, Myron; Martin, Toby; Valvo, Michael

    2006-01-01

    Tactile sensing is an important part of the development of new prosthetic hands. A number of approaches to establishing an afferent pathway back to the patient for tactile information are becoming available including tactors and direct stimulation of the afferent nerves. Tactile information can also be used by low-level control systems that perform simple tasks for the patient such as establishing a stable grasp and maintaining the grasping forces needed to hold an object. This abstract reports on the design of a small fingertip load cell based on semi-conductor strain gauges. Since this load cell is so small (measuring only 8.5mm in diameter and 6.25 mm in height), it easily fits into the tip of an anthropomorphic mechatronic hand. This load cell is tested by comparing a time series of force and moment data with reference data acquired from a much larger high-precision commercial load cell.

  6. Long-term stability of neural prosthetic control signals from silicon cortical arrays in rhesus macaque motor cortex

    Science.gov (United States)

    Chestek, Cynthia A.; Gilja, Vikash; Nuyujukian, Paul; Foster, Justin D.; Fan, Joline M.; Kaufman, Matthew T.; Churchland, Mark M.; Rivera-Alvidrez, Zuley; Cunningham, John P.; Ryu, Stephen I.; Shenoy, Krishna V.

    2011-08-01

    Cortically-controlled prosthetic systems aim to help disabled patients by translating neural signals from the brain into control signals for guiding prosthetic devices. Recent reports have demonstrated reasonably high levels of performance and control of computer cursors and prosthetic limbs, but to achieve true clinical viability, the long-term operation of these systems must be better understood. In particular, the quality and stability of the electrically-recorded neural signals require further characterization. Here, we quantify action potential changes and offline neural decoder performance over 382 days of recording from four intracortical arrays in three animals. Action potential amplitude decreased by 2.4% per month on average over the course of 9.4, 10.4, and 31.7 months in three animals. During most time periods, decoder performance was not well correlated with action potential amplitude (p > 0.05 for three of four arrays). In two arrays from one animal, action potential amplitude declined by an average of 37% over the first 2 months after implant. However, when using simple threshold-crossing events rather than well-isolated action potentials, no corresponding performance loss was observed during this time using an offline decoder. One of these arrays was effectively used for online prosthetic experiments over the following year. Substantial short-term variations in waveforms were quantified using a wireless system for contiguous recording in one animal, and compared within and between days for all three animals. Overall, this study suggests that action potential amplitude declines more slowly than previously supposed, and performance can be maintained over the course of multiple years when decoding from threshold-crossing events rather than isolated action potentials. This suggests that neural prosthetic systems may provide high performance over multiple years in human clinical trials.

  7. Structural brain abnormalities in patients with Parkinson's disease with visual hallucinations: a comparative voxel-based analysis.

    Science.gov (United States)

    Gama, Romulo Lopes; Bruin, Veralice Meireles Sales; Távora, Daniel Gurgel Fernandes; Duran, Fábio L S; Bittencourt, Lia; Tufik, Sergio

    2014-06-01

    The objective is to evaluate clinical characteristics and cerebral alterations in Parkinson's disease (PD) patients with diurnal visual hallucinations (VHs). Assessment was performed using magnetic resonance image (MRI) and voxel-based morphometry (VBM). Thirty-nine patients with PD (53.8%) and ten controls were studied. Voxel based morphology analysis was performed. Eleven patients presented diurnal VHs and among these, six had cognitive dysfunction. Patients with VHs performed worse in the mentation-related UPDRS I (p=0.005) and motor-related UPDRS III (p=0.02). Patients with VHs showed significant clusters of reduced grey matter volume compared to controls in the left opercula frontal gyrus and left superior frontal gyrus. PD without hallucinations demonstrated reduced grey matter volume in the left superior frontal gyrus compared to controls. Comparisons between patients with VHs regarding the presence of cognitive dysfunction showed that cases with cognitive dysfunction as compared to those without cognitive dysfunction showed significant clusters of reduced grey matter volume in the left opercular frontal gyrus. Cases without cognitive dysfunction had reduced grey matter substance in the left insula and left trigonal frontal gyrus. Judging from our findings, an abnormal frontal cortex, particularly left sided insula, frontal opercular, trigonal frontal gyrus and orbital frontal would make PD patients vulnerable to hallucinations. Compromise of the left operculum distinguished cases with VHs and cognitive dysfunction. Our findings reinforce the theoretical concept of a top-down visual processing in the genesis of VHs in PD.

  8. Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

    Science.gov (United States)

    Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

    2016-10-01

    Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

  9. Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

    Science.gov (United States)

    Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

    2016-12-01

    Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

  10. Visual attention capacity

    DEFF Research Database (Denmark)

    Habekost, Thomas; Starrfelt, Randi

    2009-01-01

    Psychophysical studies have identified two distinct limitations of visual attention capacity: processing speed and apprehension span. Using a simple test, these cognitive factors can be analyzed by Bundesen's Theory of Visual Attention (TVA). The method has strong specificity and sensitivity...... to patient testing, and review existing TVA-based patient studies organized by lesion anatomy. Lesions in three anatomical regions affect visual capacity: The parietal lobes, frontal cortex and basal ganglia, and extrastriate cortex. Visual capacity thus depends on large, bilaterally distributed anatomical...... networks that include several regions outside the visual system. The two visual capacity parameters are functionally separable, but seem to rely on largely overlapping brain areas....

  11. "Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca(2+) fluoroimaging".

    Science.gov (United States)

    Kobayashi, Takuma; Haruta, Makito; Sasagawa, Kiyotaka; Matsumata, Miho; Eizumi, Kawori; Kitsumoto, Chikara; Motoyama, Mayumi; Maezawa, Yasuyo; Ohta, Yasumi; Noda, Toshihiko; Tokuda, Takashi; Ishikawa, Yasuyuki; Ohta, Jun

    2016-02-16

    To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca(2+) indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca(2+) dynamics of neural cells were visualized simultaneously by fluorescence imaging.

  12. Fixed prosthetic treatment in patients with cleft lip and palate

    Directory of Open Access Journals (Sweden)

    Bajevska Jagoda

    2017-01-01

    Full Text Available Introduction. The prosthetic treatment of patients with cleft palate includes various treatment options such as fixed partial dentures, removable partial prosthesis, etc. The type of prosthetic appliance is determined by the oral health of each individual and the circumstances. We presented three adult patients with the cleft lip and palate subjected to prosthetic treatment. Case report. From the possible prosthetic solutions according to the conditions in the oral cavity and the circumstances, fixed partial dentures veneered with composite or ceramic were chosen. A proper relationship between the teeth was reached with the fixed partial dentures, and function established, the phonetics improved and satisfying aesthetics effect accomplished improving the profile appearance of the patient’s face. Plastic surgery of the nose was performed after that. Conclusion. Multidisclipinary treatment is necessary for favourable long-term outcome in cleft lip and palate patients.

  13. Antithrombotic Therapy in Patients with Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    Mohamed HA

    2009-01-01

    Full Text Available Patients with mechanical valve prostheses require a lifelong anticoagulant treatment. The combined use of Warfarin and low-dose aspirin appears to reduce the risk of valve thrombosis and systemic embolism at a low risk of bleeding. The management of women with prosthetic heart valves during pregnancy poses a particular challenge, as there are no available controlled clinical trials to provide guidelines for effective antithrombotic therapy. Oral anticoagulants, such as Warfarin, cause foetal embryopathy; unfractionated heparin and low-molecular-weight heparin have been reported to be ineffective in preventing thromboembolic complications.This article discusses the available data and the most recent guidelines in the antithrombotic management of patients with prosthetic valves, and antithrombotic therapy in various clinical situations such as pregnant women with prosthetic heart valves, and patients with prosthetic heart valves undergoing noncardiac surgery.

  14. Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants

    OpenAIRE

    Camargos, Germana de Villa; SOTTO-MAIOR,Bruno Salles; Silva,Wander José da; Priscilla Cardoso LAZARI; Del Bel Cury, Altair Antoninha

    2016-01-01

    Abstract This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical), implant connection (external hexagon, EH or internal hexagon, IH), and occlusal loading (axial or oblique), for both i...

  15. Prosthetic Knee Septic Arthritis due to Pseudomonas stutzeri

    Directory of Open Access Journals (Sweden)

    Jihad Bishara

    2000-01-01

    Full Text Available Prosthetic joint infection is usually caused by Staphylococcus aureus, coagulase-negative staphylococci and, less commonly, by Gram-negative bacilli and anaerobes. A case of prosthetic joint infection due to Pseudomonas stutzeri in a 73-year-old female with acute promyelocytic leukemia is presented, and the pertinent literature is reviewed. Although the patient had prolonged neutropenia, the infection was successfully treated with antibiotics and without artificial joint replacement.

  16. Prosthetic Rehabilitation of Amputated Thumb: A Simplified Approach

    OpenAIRE

    2013-01-01

    This case report presents a case of prosthetic rehabilitation of an amputated thumb. It emphasizes that prosthetic replacement is a better option for aesthetic and psychological improvement, particularly in cases where the victim is unwilling to undergo complicated surgical procedures for reconstruction of thumb or where functioning of thumb cannot be restored even by multiple surgeries. In the present case, a 20 years old female patient, with missing thumb of her right hand was rehabilitated...

  17. [Prevention of complications fixed restorations in prosthetic patients with hypertension].

    Science.gov (United States)

    2014-04-01

    The author on the basis of clinical and laboratory methods justified, that the use of locally cream "Solcoseryl-Denta" persons suffering from arterial hypertension, increase the speed of recovery of normal epithelial layer of the cells of the mucous membranes of the oral cavity, and, consequently, prevents the development of complications in prosthetics. On the basis of research identified the need in developing a method of prevention of inflammatory complications in prosthetic patients with arterial hypertension.

  18. Rotationplasty with Vascular Reconstruction for Prosthetic Knee Joint Infection

    Directory of Open Access Journals (Sweden)

    Masahide Fujiki

    2015-01-01

    Full Text Available Rotationplasty is used most often as a function-preserving salvage procedure after resection of sarcomas of the lower extremity; however, it is also used after infection of prosthetic knee joints. Conventional vascular management during rotationplasty is to preserve and coil major vessels, but recently, transection and reanastomosis of the major vessels has been widely performed. However, there has been little discussion regarding the optimal vascular management of rotationplasty after infection of prosthetic knee joints because rotationplasty is rarely performed for this indication. We reviewed four patients who had undergone resection of osteosarcomas of the femur, placement of a prosthetic knee joint, and rotationplasty with vascular reconstruction from 2010 to 2013. The mean interval between prosthetic joint replacement and rotationplasty was 10.4 years and the mean interval between the diagnosis of prosthesis infection and rotationplasty was 7.9 years. Rotationplasty was successful in all patients; however, in one patient, arterial thrombosis developed and necessitated urgent surgical removal and arterial reconstruction. All patients were able to walk independently with a prosthetic limb after rehabilitation. Although there is no consensus regarding the most appropriate method of vascular management during rotationplasty for revision of infected prosthetic joints, vascular transection and reanastomosis is a useful option.

  19. Predicting prosthetic prescription after major lower-limb amputation.

    Science.gov (United States)

    Resnik, Linda; Borgia, Matthew

    2015-01-01

    We describe prosthetic limb prescription in the first year following lower-limb amputation and examine the relationship between amputation level, geographic region, and prosthetic prescription. We analyzed 2005 to 2010 Department of Veterans Affairs (VA) Inpatient and Medical Encounters SAS data sets, Vital Status death data, and National Prosthetic Patient Database data for 9,994 Veterans who underwent lower-limb amputation at a VA hospital. Descriptive statistics and bivariates were examined. Cox proportional hazard models identified factors associated with prosthetic prescription. Analyses showed that amputation level was associated with prosthetic prescription. The hazard ratios (HRs) were 1.41 for ankle amputation and 0.46 for transfemoral amputation compared with transtibial amputation. HRs for geographic region were Northeast = 1.49, Upper Midwest = 1.26, and West = 1.39 compared with the South (p amputation were most likely to be prescribed a prosthesis and people with transfemoral amputation were least likely. Geographic variation in prosthetic prescription exists in the VA and further research is needed to explain why.

  20. Distribution of serotonin and FMRF-amide in the brain of Lymnaea stagnalis with respect to the visual system

    Institute of Scientific and Technical Information of China (English)

    Oksana P.TUCHINA; Valery V.ZHUKOV; Victor B.MEYER-ROCHOW

    2012-01-01

    Despite serotonin's and FMRF-amide's wide distribution in the nervous system of invertebrates and their importance as neurotransmitters,the exact roles they play in neuronal networks leaves many questions.We mapped the presence of serotonin and FMRF-amide-immunoreactivity in the central nervous system and eyes of the pond snail Lymnaea stagnalis and interpreted the results in connection with our earlier findings on the central projections of different peripheral nerves.Since the chemical nature of the intercellular connections in the retina of L.stagnalis is still largely unknown,we paid special attention to clarifying the role of serotonin and FMRF-amide in the visual system of this snail and compared our findings with those reported from other species.At least one serotonin- and one FMRF-amidergic fibre were labeled in each optic nerve,and since no cell bodies in the eye showed immunoreactivity to these neurotransmitters,we believe that efferent fibres with somata located in the central ganglia branch at the base of the eye and probably release 5HT and FMRF-amide as neuro-hormones.Double labelling revealed retrograde transport of neurobiotin through the optic nerve,allowing us to conclude that the central pathways and serotonin- and FMRF-amide-immunoreactive cells and fibres have different locations in the CNS in L.stagnalis.The chemical nature of the fibres,which connect the two eyes in L.stagnalis,is neither serotoninergic nor FMRF-amidergic.

  1. Multi-Brain BCI Games: Where to Go from Here?

    NARCIS (Netherlands)

    Nijholt, Anton; Spink, Andrew; Riedel, Gernot; Zhou, Lisanne; Albatel, Rami; Gurrin, Cathal

    2016-01-01

    Clinical research on brain-computer interaction has focused on patients and assistive technology for disabled users. How can we provide an ALS patient with the possibility to communicate with the outside world using his or her brains only? Or, how can an artificial limb or prosthetic device be contr

  2. A comparison of two spelling Brain-Computer Interfaces based on visual P3 and SSVEP in Locked-In Syndrome.

    Directory of Open Access Journals (Sweden)

    Adrien Combaz

    Full Text Available OBJECTIVES: We study the applicability of a visual P3-based and a Steady State Visually Evoked Potentials (SSVEP-based Brain-Computer Interfaces (BCIs for mental text spelling on a cohort of patients with incomplete Locked-In Syndrome (LIS. METHODS: Seven patients performed repeated sessions with each BCI. We assessed BCI performance, mental workload and overall satisfaction for both systems. We also investigated the effect of the quality of life and level of motor impairment on the performance. RESULTS: All seven patients were able to achieve an accuracy of 70% or more with the SSVEP-based BCI, compared to 3 patients with the P3-based BCI, showing a better performance with the SSVEP BCI than with the P3 BCI in the studied cohort. Moreover, the better performance of the SSVEP-based BCI was accompanied by a lower mental workload and a higher overall satisfaction. No relationship was found between BCI performance and level of motor impairment or quality of life. CONCLUSION: Our results show a better usability of the SSVEP-based BCI than the P3-based one for the sessions performed by the tested population of locked-in patients with respect to all the criteria considered. The study shows the advantage of developing alternative BCIs with respect to the traditional matrix-based P3 speller using different designs and signal modalities such as SSVEPs to build a faster, more accurate, less mentally demanding and more satisfying BCI by testing both types of BCIs on a convenience sample of LIS patients.

  3. Clinical feasibility of brain-computer interface based on steady-state visual evoked potential in patients with locked-in syndrome: Case studies.

    Science.gov (United States)

    Hwang, Han-Jeong; Han, Chang-Hee; Lim, Jeong-Hwan; Kim, Yong-Wook; Choi, Soo-In; An, Kwang-Ok; Lee, Jun-Hak; Cha, Ho-Seung; Hyun Kim, Seung; Im, Chang-Hwan

    2017-03-01

    Although the feasibility of brain-computer interface (BCI) systems based on steady-state visual evoked potential (SSVEP) has been extensively investigated, only a few studies have evaluated its clinical feasibility in patients with locked-in syndrome (LIS), who are the main targets of BCI technology. The main objective of this case report was to share our experiences of SSVEP-based BCI experiments involving five patients with LIS, thereby providing researchers with useful information that can potentially help them to design BCI experiments for patients with LIS. In our experiments, a four-class online SSVEP-based BCI system was implemented and applied to four of five patients repeatedly on multiple days to investigate its test-retest reliability. In the last experiments with two of the four patients, the practical usability of our BCI system was tested using a questionnaire survey. All five patients showed clear and distinct SSVEP responses at all four fundamental stimulation frequencies (6, 6.66, 7.5, 10 Hz), and responses at harmonic frequencies were also observed in three patients. Mean classification accuracy was 76.99% (chance level = 25%). The test-retest reliability experiments demonstrated stable performance of our BCI system over different days even when the initial experimental settings (e.g., electrode configuration, fixation time, visual angle) used in the first experiment were used without significant modifications. Our results suggest that SSVEP-based BCI paradigms might be successfully used to implement clinically feasible BCI systems for severely paralyzed patients.

  4. Adaptation to Phosphene Parameters Based on Multi-Object Recognition Using Simulated Prosthetic Vision.

    Science.gov (United States)

    Xia, Peng; Hu, Jie; Peng, Yinghong

    2015-12-01

    Retinal prostheses for the restoration of functional vision are under development and visual prostheses targeting proximal stages of the visual pathway are also being explored. To investigate the experience with visual prostheses, psychophysical experiments using simulated prosthetic vision in normally sighted individuals are necessary. In this study, a helmet display with real-time images from a camera attached to the helmet provided the simulated vision, and experiments of recognition and discriminating multiple objects were used to evaluate visual performance under different parameters (gray scale, distortion, and dropout). The process of fitting and training with visual prostheses was simulated and estimated by adaptation to the parameters with time. The results showed that the increase in the number of gray scale and the decrease in phosphene distortion and dropout rate improved recognition performance significantly, and the recognition accuracy was 61.8 ± 7.6% under the optimum condition (gray scale: 8, distortion: k = 0, dropout: 0%). The adaption experiments indicated that the recognition performance was improved with time and the effect of adaptation to distortion was greater than dropout, which implies the difference of adaptation mechanism to the two parameters.

  5. Intracortical inhibition is modulated by phase of prosthetic rehabilitation in transtibial amputees

    Directory of Open Access Journals (Sweden)

    Brenton eHordacre

    2015-05-01

    Full Text Available Reorganisation of primary motor cortex (M1 is well described in long-term lower limb amputees. In contrast cortical reorganisation during the rehabilitation period after amputation is poorly understood. Thirteen transtibial amputees and thirteen gender matched control participants of similar age were recruited. Transcranial magnetic stimulation was used to assess corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were conducted at admission, prosthetic casting, first walk and discharge. Gait variability at discharge was assessed as a functional measure. Compared to controls, amputees had reduced short-latency intracortical inhibition for the ipsilateral M1 at admission (p=0.01. Analysis across rehabilitation revealed short-latency intracortical inhibition was reduced for the contralateral M1 at first walk compared to discharge (p=0.003. For the ipsilateral M1 both short and long-latency intracortical inhibition were reduced at admission (p<0.05 and prosthetic casting (p<0.02. Analysis of the neurophysiology and gait function revealed several interesting relationships. For the contralateral M1, reduced inhibition at admission (p=0.04 and first walk (p=0.05 was associated with better gait function. For the ipsilateral M1, reduced inhibition at discharge (p=0.05 was associated with poor gait function. This study characterised intracortical excitability in rehabilitating amputees. A dichotomous relationship between reduced intracortical inhibition for each M1 and gait function was observed at different times. Intracortical inhibition may be an appropriate cortical biomarker of gait function in lower limb amputees during rehabilitation, but requires further investigation. Understanding M1 intracortical excitability of amputees undertaking prosthetic rehabilitation provides insight into brain reorganisation in the sub-acute post amputation period and may guide future studies seeking to improve rehabilitation

  6. Prosthetic rehabilitation of the upper limb amputee

    Directory of Open Access Journals (Sweden)

    Bernard O′Keeffe

    2011-01-01

    Full Text Available The loss of all or part of the arm is a catastrophic event for a patient and a significant challenge to rehabilitation professionals and prosthetic engineers. The large, upper extremity amputee population in India has, historically, been poorly served, with most having no access to support or being provided with ineffective prostheses. In recent years, the arrival of organisations like Otto Bock has made high quality service standards and devices accessible to more amputees. This review attempts to provide surgeons and other medical professionals with an overview of the multidisciplinary, multistage rehabilitation process and the solution options available. With worldwide upper extremity prosthesis rejection rates at significant levels, the review also describes some of the factors which influence the outcome. This is particularly relevant in the Indian context where the service can involve high cost investments. It is the responsibility of all contributing professionals to guide vulnerable patients through the process and try to maximise the benefit that can be obtained within the resources available.

  7. Peri-prosthetic fracture vibration testing

    Energy Technology Data Exchange (ETDEWEB)

    Cruce, Jesse R [Los Alamos National Laboratory; Erwin, Jenny R [Los Alamos National Laboratory; Remick, Kevin R [Los Alamos National Laboratory; Cornwell, Phillip J [Los Alamos National Laboratory; Menegini, R. Michael [INDIANA UNIV.; Racanelli, Joe [STRYKER ORTHOPARDICS

    2010-11-08

    The purpose of this study was to establish a test setup and vibration analysis method to predict femoral stem seating and prevent bone fracture using accelerometer and force response data from an instrumented stem and impactor. This study builds upon earlier studies to identify a means to supplement a surgeon's tactile and auditory senses by using damage identification techniques normally used for civil and mechanical structures. Testing was conducted using foam cortical shell sawbones prepared for stems of different geometries. Each stem was instrumented with an accelerometer. Two impactor designs were compared: a monolithic impactor and a two-piece impactor, each with an integrated load cell and accelerometer. Acceleration and force measurements were taken in the direction of impaction. Comparisons between different methods of applying an impacting force were made, including a drop tower and a surgical hammer. The effect of varying compliance on the data was also investigated. The ultimate goal of this study was to assist in the design of an integrated portable data acquisition system capable of being used in future cadaveric testing. This paper will discuss the experimental setup and the subsequent results of the comparisons made between impactors, prosthetic geometries, compliances, and impact methods. The results of this study can be used for both future replicate testing as well as in a cadaveric environment.

  8. Toxicology of antimicrobial nanoparticles for prosthetic devices

    Science.gov (United States)

    Nuñez-Anita, Rosa Elvira; Acosta-Torres, Laura Susana; Vilar-Pineda, Jorge; Martínez-Espinosa, Juan Carlos; de la Fuente-Hernández, Javier; Castaño, Víctor Manuel

    2014-01-01

    Advances in nanotechnology are producing an accelerated proliferation of new nanomaterial composites that are likely to become an important source of engineered health-related products. Nanoparticles with antifungal effects are of great interest in the formulation of microbicidal materials. Fungi are found as innocuous commensals and colonize various habitats in and on humans, especially the skin and mucosa. As growth on surfaces is a natural part of the Candida spp. lifestyle, one can expect that Candida organisms colonize prosthetic devices, such as dentures. Macromolecular systems, due to their properties, allow efficient use of these materials in various fields, including the creation of reinforced nanoparticle polymers with antimicrobial activity. This review briefly summarizes the results of studies conducted during the past decade and especially in the last few years focused on the toxicity of different antimicrobial polymers and factors influencing their activities, as well as the main applications of antimicrobial polymers in dentistry. The present study addresses aspects that are often overlooked in nanotoxicology studies, such as careful time-dependent characterization of agglomeration and ion release. PMID:25187703

  9. Prototyping Cognitive Prosthetics for People with Dementia

    Science.gov (United States)

    Davies, Richard; Nugent, Chris D.; Donnelly, Mark

    In the COGKNOW project, a cognitive prosthetic has been developed through the application of Information and Communication Technology (ICT)-based services to address the unmet needs and demands of persons with dementia. The primary aim of the developed solution was to offer guidance with conducting everyday activities for persons with dementia. To encourage a user-centred design process, a three-phased methodology was introduced to facilitate cyclical prototype development. At each phase, user input was used to guide the future development. As a prerequisite to the first phase of development, user requirements were gathered to identify a small set of functional requirements from which a number of services were identified. Following implementation of these initial services, the prototype was evaluated on a cohort of users and, through observing their experiences and recording their feedback, the design was refined and the prototype redeveloped to include a number of additional services in the second phase. The current chapter provides an overview of the services designed and developed in the first two phases.

  10. BrainHQ visual training can improve the memory of stroke survivors%BrainHQ视觉训练改善脑卒中患者记忆功能的效果分析

    Institute of Scientific and Technical Information of China (English)

    王静; 毛荣华; 陈长香; 李淑杏; 张敏; 窦娜

    2016-01-01

    Objective To investigate the efficacy of BrainHQ visual training in rehabilitating memory function among stroke survivors.Methods Sixty stroke patients with memory disorders were recruited from the rehabilitation center of Tangshan Workers' Hospital.They were randomly assigned to a control group or an intervention group,each of 30.Both groups accepted conventional rehabilitation,while the intervention group was additionally given BrainHQ visual training five times a week for 30 minutes,lasting four weeks.Before and after the treatment,both groups completed the Rivermead behavioral memory test.Results After the 4 weeks of treatment,the average scores in recalling full names,recalling hidden items,recalling appointments,recognizing pictures,recognizing faces,recalling a story immediately,delayed story recall,recalling a route promptly,delayed route recall and the average total score in both groups were all significantly higher than before the treatment.The treatment group scored significantly better than the control group except in recalling hidden items,and recognizing faces and pictures.Conclusion BrainHQ visual training can improve the memory of stroke survivors.%目的 观察BrainHQ视觉训练对脑卒中患者记忆功能障碍的康复效果.方法 选取唐山市工人医院下属的康复医院脑卒中后记忆障碍患者60例,采用分层随机化的方式分为对照组(n=30)和干预组(n=30),对照组进行常规康复治疗,干预组在对照组的基础上加用BrainHQ视觉训练.治疗前及治疗4周后(治疗后),采用Rivermead行为记忆测验第2版(RBMT-Ⅱ)分别对2组患者的记忆功能进行测评.结果 治疗后,干预组的回忆姓名、回忆被藏物品、回忆预约、图片再认、脸部再认、立即回忆故事、故事延迟回忆、日期、立即回忆路线、路线延迟回忆、信息延迟回忆及总标准分12项评分[分别为(1.30±0.54)分、(1.83±0.38)分、(1.20±0.41)分、(2.00±0.00)分、(1.83±0.38)

  11. 100 top-cited scientific papers in limb prosthetics.

    Science.gov (United States)

    Eshraghi, Arezoo; Osman, Noor Azuan Abu; Gholizadeh, Hossein; Ali, Sadeeq; Shadgan, Babak

    2013-11-17

    Research has tremendously contributed to the developments in both practical and fundamental aspects of limb prosthetics. These advancements are reflected in scientific articles, particularly in the most cited papers. This article aimed to identify the 100 top-cited articles in the field of limb prosthetics and to investigate their main characteristics. Articles related to the field of limb prosthetics and published in the Web of Knowledge database of the Institute for Scientific Information (ISI) from the period of 1980 to 2012. The 100 most cited articles in limb prosthetics were selected based on the citation index report. All types of articles except for proceedings and letters were included in the study. The study design and level of evidence were determined using Sackett's initial rules of evidence. The level of evidence was categorized either as a systematic review or meta-analysis, randomized controlled trial, cohort study, case-control study, case series, expert opinion, or design and development. The top cited articles in prosthetics were published from 1980 to 2012 with a citation range of 11 to 90 times since publication. The mean citation rate was 24.43 (SD 16.7) times. Eighty-four percent of the articles were original publications and were most commonly prospective (76%) and case series studies (67%) that used human subjects (96%) providing level 4 evidence. Among the various fields, rehabilitation (47%), orthopedics (29%), and sport sciences (28%) were the most common fields of study. The study established that studies conducted in North America and were written in English had the highest citations. Top cited articles primarily dealt with lower limb prosthetics, specifically, on transtibial and transradial prosthetic limbs. Majority of the articles were experimental studies.

  12. sfDM: Open-Source Software for Temporal Analysis and Visualization of Brain Tumor Diffusion MR Using Serial Functional Diffusion Mapping.

    Science.gov (United States)

    Ceschin, Rafael; Panigrahy, Ashok; Gopalakrishnan, Vanathi

    2015-01-01

    A major challenge in the diagnosis and treatment of brain tumors is tissue heterogeneity leading to mixed treatment response. Additionally, they are often difficult or at very high risk for biopsy, further hindering the clinical management process. To overcome this, novel advanced imaging methods are increasingly being adapted clinically to identify useful noninvasive biomarkers capable of disease stage characterization and treatment response prediction. One promising technique is called functional diffusion mapping (fDM), which uses diffusion-weighted imaging (DWI) to generate parametric maps between two imaging time points in order to identify significant voxel-wise changes in water diffusion within the tumor tissue. Here we introduce serial functional diffusion mapping (sfDM), an extension of existing fDM methods, to analyze the entire tumor diffusion profile along the temporal course of the disease. sfDM provides the tools necessary to analyze a tumor data set in the context of spatiotemporal parametric mapping: the image registration pipeline, biomarker extraction, and visualization tools. We present the general workflow of the pipeline, along with a typical use case for the software. sfDM is written in Python and is freely available as an open-source package under the Berkley Software Distribution (BSD) license to promote transparency and reproducibility.

  13. Music Alters Visual Perception

    NARCIS (Netherlands)

    Jolij, Jacob; Meurs, Maaike

    2011-01-01

    Background: Visual perception is not a passive process: in order to efficiently process visual input, the brain actively uses previous knowledge (e. g., memory) and expectations about what the world should look like. However, perception is not only influenced by previous knowledge. Especially the pe

  14. In situ elemental analysis and visualization in cryofixed nervous tissues. X-ray microanalytical investigations of embryological and mature brain, inner ear, photoreceptors, muscle and muscle spindles. Comparison of preparation methods for analysis and visualization at cellular and subcellular levels.

    Science.gov (United States)

    Wróblewski, R

    1989-07-01

    visualization of the specimens prepared by cryomethods. Charging, low contrast, mass loss and contamination, which are often negligible in conventional electron microscopy, have still to be solved in XRMA of cryoprepared specimens. However, the methods of semi-thin and thick cryosectioning and low-temperature embedding were successfully used for analysis of cells and organelles and for the study of fluids in restricted biological spaces such as the inner ear, muscle spindles and ventricles of the brain in rats. Accordingly, examinations which were impossible by micropuncture and ion selective techniques could be carried out by XRMA.(ABSTRACT TRUNCATED AT 400 WORDS)

  15. Prosthetic hand sensor placement: Analysis of touch perception during the grasp

    Directory of Open Access Journals (Sweden)

    Mirković Bojana

    2014-01-01

    Full Text Available Humans rely on their hands to perform everyday tasks. The hand is used as a tool, but also as the interface to “sense” the world. Current prosthetic hands are based on sophisticated multi-fingered structures, and include many sensors which counterpart natural proprioceptors and exteroceptors. The sensory information is used for control, but not sent to the user of the hand (amputee. Grasping without sensing is not good enough. This research is part of the development of the sensing interface for amputees, specifically addressing the analysis of human perception while grasping. The goal is to determine the small number of preferred positions of sensors on the prosthetic hand. This task has previously been approached by trying to replicate a natural sensory system characteristic for healthy humans, resulting in a multitude of redundant sensors and basic inability to make the patient aware of the sensor readings on the subconscious level. We based our artificial perception system on the reported sensations of humans when grasping various objects without seeing the objects (obstructed visual feedback. Subjects, with no known sensory deficits, were asked to report on the touch sensation while grasping. The analysis included objects of various sizes, weights, textures and temperatures. Based on this data we formed a map of the preferred positions for the sensors that is appropriate for five finger human-like robotic hand. The final map was intentionally minimized in size (number of sensors.

  16. “Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca2+ fluoroimaging”

    Science.gov (United States)

    Kobayashi, Takuma; Haruta, Makito; Sasagawa, Kiyotaka; Matsumata, Miho; Eizumi, Kawori; Kitsumoto, Chikara; Motoyama, Mayumi; Maezawa, Yasuyo; Ohta, Yasumi; Noda, Toshihiko; Tokuda, Takashi; Ishikawa, Yasuyuki; Ohta, Jun

    2016-02-01

    To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca2+ indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca2+ dynamics of neural cells were visualized simultaneously by fluorescence imaging.

  17. Hand Transplantation Versus Hand Prosthetics: Pros and Cons.

    Science.gov (United States)

    Salminger, S; Roche, A D; Sturma, A; Mayer, J A; Aszmann, O C

    Composite tissue transplantation and new developments in the field of prosthetics have opened new frontiers in the restoration of function among upper limb amputees. It is now possible to restore hand function in affected patients; however, the indications, advantages, and limitations for either hand transplantation or prosthetic fitting must be carefully considered depending on the level and extent of the limb loss. Hand transplantation allows comprehensive hand function to be restored, yet composite tissue transplantation comes with disadvantages, making this method a controversial topic in the hand surgical community. Alternatively, prosthetic limb replacement represents the standard of care for upper limb amputees, but results in the known limitations of function, sensation, and usage. The indication for hand transplantation or prosthetic fitting strongly depends on the level of amputation, as well as on the extent (unilateral/bilateral) of the amputation. In this review, we discuss the advantages and disadvantages of hand transplantation and prosthetic replacement for upper limb amputees in general, as well as in regard to the different levels of amputation.

  18. Methods for characterization of mechanical and electrical prosthetic vacuum pumps

    Directory of Open Access Journals (Sweden)

    Oluseeni Komolafe, PhD

    2013-11-01

    Full Text Available Despite increasingly widespread adoption of vacuum-assisted suspension systems in prosthetic clinical practices, there remain gaps in the body of scientific knowledge guiding clinicians’ choices of existing products. In this study, we identified important pump-performance metrics and developed techniques to objectively characterize the evacuation performance of prosthetic vacuum pumps. The sensitivity of the proposed techniques was assessed by characterizing the evacuation performance of two electrical (Harmony e-Pulse [Ottobock; Duderstadt, Germany] and LimbLogic VS [Ohio Willow Wood; Mt. Sterling, Ohio] and three mechanical (Harmony P2, Harmony HD, and Harmony P3 [Ottobock] prosthetic pumps in bench-top testing. Five fixed volume chambers ranging from 33 cm3 (2 in.3 to 197 cm3 (12 in.3 were used to represent different air volume spaces between a prosthetic socket and a liner-clad residual limb. All measurements were obtained at a vacuum gauge pressure of 57.6 kPa (17 inHg. The proposed techniques demonstrated sensitivity to the different electrical and mechanical pumps and, to a lesser degree, to the different setting adjustments of each pump. The sensitivity was less pronounced for the mechanical pumps, and future improvements for testing of mechanical vacuum pumps were proposed. Overall, this study successfully offers techniques feasible as standards for assessing the evacuation performance of prosthetic vacuum pump devices.

  19. Biomechanical design considerations for transradial prosthetic interface: A review.

    Science.gov (United States)

    Sang, Yuanjun; Li, Xiang; Luo, Yun

    2016-03-01

    Traditional function and comfort assessment of transradial prostheses pay scant attention to prosthetic interface. With better understanding of the biomechanics of prosthetic interface comes better efficiency and safety for interface design; in this way, amputees are more likely to accept prosthetic usage. This review attempts to provide design and selection criteria of transradial interface for prosthetists and clinicians. Various transradial socket types in the literature were chronologically reviewed. Biomechanical discussion of transradial prosthetic interface design from an engineering point of view was also done. Suspension control, range of motion, stability, as well as comfort and safety of socket designs have been considered in varying degrees in the literature. The human-machine interface design should change from traditional "socket design" to new "interface design." From anatomy and physiology to biomechanics of the transradial residual limb, the force and motion transfer, together with comfort and safety, are the two main aspects in prosthetic interface design. Load distribution and transmission should mainly rely on achieving additional skeletal control through targeted soft tissue relief. Biomechanics of the residual limb soft tissues should be studied to find the relationship between mechanical properties and the comfort and safety of soft tissues.

  20. Prosthetic alignment effects on gait symmetry: a case study.

    Science.gov (United States)

    Andres, R O; Stimmel, S K

    1990-05-01

    The loss of a significant portion of a lower extremity causes changes in the usual pattern of human ambulation. These changes have been documented kinematically, kinetically and metabolically, giving insight into the costs of limb amputation relative to ambulatory efforts. The role of the prosthetist is to provide a limb substitute to achieve the best gait performance, while assuring maximum comfort for the patient. This case study examined the effects of antero-posterior alignment of a below-knee prosthesis on sagittal plane gait kinematics by comparing the anatomical side with the prosthetic side. The greatest changes due to variations of alignment were found during the prosthetic stance phase; knee angles showed the greatest asymmetry between anatomical and prosthetic sides. The stance phase on the prosthetic side was reduced with anterior socket displacement due to early knee flexion and toe-off. Posterior socket displacement caused a greater maximum centre of gravity height, but anterior socket displacement caused greater knee flexion which decreased the maximum centre of gravity height. Asymmetries in temporal and other kinematic parameters were not always minimal at the optimal alignment subjectively selected by a certified prosthetist. Comparisons of asymmetry ratios with prosthetic side data revealed the subclinical sensitivity of this amputee to antero-posterior alignment discrepancies.

  1. Methods for characterization of mechanical and electrical prosthetic vacuum pumps.

    Science.gov (United States)

    Komolafe, Oluseeni; Wood, Sean; Caldwell, Ryan; Hansen, Andrew; Fatone, Stefania

    2013-01-01

    Despite increasingly widespread adoption of vacuum-assisted suspension systems in prosthetic clinical practices, there remain gaps in the body of scientific knowledge guiding clinicians' choices of existing products. In this study, we identified important pump-performance metrics and developed techniques to objectively characterize the evacuation performance of prosthetic vacuum pumps. The sensitivity of the proposed techniques was assessed by characterizing the evacuation performance of two electrical (Harmony e-Pulse [Ottobock; Duderstadt, Germany] and LimbLogic VS [Ohio Willow Wood; Mt. Sterling, Ohio]) and three mechanical (Harmony P2, Harmony HD, and Harmony P3 [Ottobock]) prosthetic pumps in bench-top testing. Five fixed volume chambers ranging from 33 cm(3) (2 in.(3)) to 197 cm(3) (12 in.(3)) were used to represent different air volume spaces between a prosthetic socket and a liner-clad residual limb. All measurements were obtained at a vacuum gauge pressure of 57.6 kPa (17 inHg). The proposed techniques demonstrated sensitivity to the different electrical and mechanical pumps and, to a lesser degree, to the different setting adjustments of each pump. The sensitivity was less pronounced for the mechanical pumps, and future improvements for testing of mechanical vacuum pumps were proposed. Overall, this study successfully offers techniques feasible as standards for assessing the evacuation performance of prosthetic vacuum pump devices.

  2. Recent advancements in prosthetic hand technology.

    Science.gov (United States)

    Saikia, Angana; Mazumdar, Sushmi; Sahai, Nitin; Paul, Sudip; Bhatia, Dinesh; Verma, Suresh; Rohilla, Punit Kumar

    2016-07-01

    Recently, significant advances over the past decade have been made in robotics, artificial intelligence and other cognitive related fields, allowing development of highly sophisticated bio-mimetic robotics systems. In addition, enormous number of robots have been designed and assembled by explicitly realising their biological oriented behaviours. To enhance skill behaviours and adequate grasping abilities in these devices, a new phase of dexterous hands has been developed recently with bio-mimetically oriented and bio-inspired functionalities. The aim in writing this review paper is to present a detailed insight towards the development of the bio-mimetic based dexterous robotic multi-fingered artificial hand. An "ideal" upper limb prosthesis should be perceived as a part of their natural body by the amputee and should replicate sensory-motor capabilities of the amputated limb. Upper-limb amputations are most often the result of sudden trauma to the body, although they also can be caused by malignancy, congenital deficiencies and vascular diseases. This paper discusses the different bio-mimetic approaches using a framework that permits for a common description of biological and technical based hand manipulation behaviour. In particular, the review focuses on a number of developments in the inspired robotic systems. In conclusion, the study found that a huge amount of research efforts in terms of kinematics, dynamics, modelling and control methodologies are being put in to improve the present hand technology, thereby providing more functionality to the prosthetic limb of the amputee. This would improve their quality-of-life and help in performing activities of daily living (ADL) tasks with comparative ease in the near future.

  3. [Experience in working out of tools of quality management of maxillofacial prosthetics].

    Science.gov (United States)

    Arutiunov, A S; Kitsul, I S; Lebedenko, I Iu; Gazazian, V V

    2011-01-01

    Expericnce of working out of tools of quality management of maxillofacial prosthetics which can be applied in clinical practice of maxillofacial orthopedy is presented. The fragment of the algorithm of maxillofacial prosthetics developed by authors is presented.

  4. Coalition for the advancement of prosthetic urology: history, accomplishments, and continuing mission.

    Science.gov (United States)

    Daubert, Gail

    2006-11-01

    The Coalition for the Advancement of Prosthetic Urology (CAPU) is the leading policy advocacy group representing the prosthetic urology community and has been very effective in educating federal health care policy-makers.

  5. 76 FR 64429 - Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2011-10-18

    ... art prosthetics and the associated rehabilitation research, development, and evaluation of such..., Amputation System of Care; and Deputy Chief Consultant, Prosthetics and Sensory Aids Service. On November 2..., Department of Veterans Affairs, Veterans Health Administration, Patient Care Services,...

  6. Insect Bio-inspired Neural Network Provides New Evidence on How Simple Feature Detectors Can Enable Complex Visual Generalization and Stimulus Location Invariance in the Miniature Brain of Honeybees

    Science.gov (United States)

    Fernando, Chrisantha

    2017-01-01

    The ability to generalize over naturally occurring variation in cues indicating food or predation risk is highly useful for efficient decision-making in many animals. Honeybees have remarkable visual cognitive abilities, allowing them to classify visual patterns by common features despite having a relatively miniature brain. Here we ask the question whether generalization requires complex visual recognition or whether it can also be achieved with relatively simple neuronal mechanisms. We produced several simple models inspired by the known anatomical structures and neuronal responses within the bee brain and subsequently compared their ability to generalize achromatic patterns to the observed behavioural performance of honeybees on these cues. Neural networks with just eight large-field orientation-sensitive input neurons from the optic ganglia and a single layer of simple neuronal connectivity within the mushroom bodies (learning centres) show performances remarkably similar to a large proportion of the empirical results without requiring any form of learning, or fine-tuning of neuronal parameters to replicate these results. Indeed, a model simply combining sensory input from both eyes onto single mushroom body neurons returned correct discriminations even with partial occlusion of the patterns and an impressive invariance to the location of the test patterns on the eyes. This model also replicated surprising failures of bees to discriminate certain seemingly highly different patterns, providing novel and useful insights into the inner workings facilitating and limiting the utilisation of visual cues in honeybees. Our results reveal that reliable generalization of visual information can be achieved through simple neuronal circuitry that is biologically plausible and can easily be accommodated in a tiny insect brain. PMID:28158189

  7. Insect Bio-inspired Neural Network Provides New Evidence on How Simple Feature Detectors Can Enable Complex Visual Generalization and Stimulus Location Invariance in the Miniature Brain of Honeybees.

    Science.gov (United States)

    Roper, Mark; Fernando, Chrisantha; Chittka, Lars

    2017-02-01

    The ability to generalize over naturally occurring variation in cues indicating food or predation risk is highly useful for efficient decision-making in many animals. Honeybees have remarkable visual cognitive abilities, allowing them to classify visual patterns by common features despite having a relatively miniature brain. Here we ask the question whether generalization requires complex visual recognition or whether it can also be achieved with relatively simple neuronal mechanisms. We produced several simple models inspired by the known anatomical structures and neuronal responses within the bee brain and subsequently compared their ability to generalize achromatic patterns to the observed behavioural performance of honeybees on these cues. Neural networks with just eight large-field orientation-sensitive input neurons from the optic ganglia and a single layer of simple neuronal connectivity within the mushroom bodies (learning centres) show performances remarkably similar to a large proportion of the empirical results without requiring any form of learning, or fine-tuning of neuronal parameters to replicate these results. Indeed, a model simply combining sensory input from both eyes onto single mushroom body neurons returned correct discriminations even with partial occlusion of the patterns and an impressive invariance to the location of the test patterns on the eyes. This model also replicated surprising failures of bees to discriminate certain seemingly highly different patterns, providing novel and useful insights into the inner workings facilitating and limiting the utilisation of visual cues in honeybees. Our results reveal that reliable generalization of visual information can be achieved through simple neuronal circuitry that is biologically plausible and can easily be accommodated in a tiny insect brain.

  8. Nanoscale Properties of Neural Cell Prosthetic and Astrocyte Response

    Science.gov (United States)

    Flowers, D. A.; Ayres, V. M.; Delgado-Rivera, R.; Ahmed, I.; Meiners, S. A.

    2009-03-01

    Preliminary data from in-vivo investigations (rat model) suggest that a nanofiber prosthetic device of fibroblast growth factor-2 (FGF-2)-modified nanofibers can correctly guide regenerating axons across an injury gap with aligned functional recovery. Scanning Probe Recognition Microscopy (SPRM) with auto-tracking of individual nanofibers is used for investigation of the key nanoscale properties of the nanofiber prosthetic device for central nervous system tissue engineering and repair. The key properties under SPRM investigation include nanofiber stiffness and surface roughness, nanofiber curvature, nanofiber mesh density and porosity, and growth factor presentation and distribution. Each of these factors has been demonstrated to have global effects on cell morphology, function, proliferation, morphogenesis, migration, and differentiation. The effect of FGF-2 modification on the key nanoscale properties is investigated. Results from the nanofiber prosthetic properties investigations are correlated with astrocyte response to unmodified and FGF-2 modified scaffolds, using 2D planar substrates as a control.

  9. Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants.

    Science.gov (United States)

    Camargos, Germana de Villa; Sotto-Maior, Bruno Salles; Silva, Wander José da; Lazari, Priscilla Cardoso; Del Bel Cury, Altair Antoninha

    2016-05-31

    This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical), implant connection (external hexagon, EH or internal hexagon, IH), and occlusal loading (axial or oblique), for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone.

  10. Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants

    Directory of Open Access Journals (Sweden)

    Germana de Villa CAMARGOS

    2016-01-01

    Full Text Available Abstract This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical, implant connection (external hexagon, EH or internal hexagon, IH, and occlusal loading (axial or oblique, for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone.

  11. Prosthetic pollicization following thumb amputation: A case report

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar

    2014-04-01

    Full Text Available The thumb contributes over 50% hand function, which is generally divided into motional, sensory and cosmetic functions. Optimal management of thumb loss necessitates individual consideration of surgical versus prosthetic options, in relation to the needs and circumstances of each patient. This paper presents a case of prosthetic pollicization of an amputated thumb and emphasizes on the fact that the prosthetic replacement has a definite edge over surgical procedures, where amputees refuse to undergo more complicated surgical procedures. The patient was rehabilitated successfully by a noninvasive and cost-effective approach by using high temperature-vulcanized (HTV silicone material and retaining the prosthesis with medical adhesives. On 3 months recall appointment, no complications were found. The prosthesis was in good shape, without need for any repairs.

  12. Surgical-prosthetic treatment of large mandibular cysts

    Directory of Open Access Journals (Sweden)

    Džambas Ljubiša D.

    2003-01-01

    Full Text Available This paper presents a combined surgical-prosthetic procedure of reconstructing mandibular bone defect in a 53 year old patient, following enucleation of a mandibular cyst (Cystectomy Partsch II. After a thorough diagnostic evaluation, a surgical procedure was planned with the particular attention to the nature of the disease, patient’s condition, size and extension of the cyst, tissue loss, and the possibilities of prosthetic management of a mandibular bone defect with partial postresection dental prosthesis. It is of great importance to point to the significance of teamwork of a maxillofacial surgeon and a specialist in prosthodontics. This kind of cooperation provided very effective and less risky soft tissue, as well as bone tissue regeneration (osteogenesis. The patient’s recovery was fast, and he could return to his daily activities and work without significant changes regarding quality of life after surgery and prosthetic treatment.

  13. Prosthetic hand control using motion discrimination from EMG signals.

    Science.gov (United States)

    Kurisu, Naoyuki; Tsujiuchi, Nobutaka; Koizumi, Takayuki

    2009-01-01

    In this report, we improve the motion discrimination method from electromyogram (EMG) for a prosthetic hand and propose prosthetic hand control. In the past, we proved that a motion discrimination method using conic models could discriminate three hand motions without the incorrect discriminations that the elbow motions cause. In this research, to increase discrimination accuracy of motion discrimination using conic models, we propose a feature extraction method using quadratic polynomials. Additionally, because many prosthetic hands using motion discrimination have constant motion speed that can't be controlled, we propose an angular velocity generation method using multiple regression models. We verified these methods by controlling the 3D hand model. In the experiment, the proposed method could discriminate five motions at a rate of above 90 percent without the incorrect discriminations that elbow motions cause. Moreover, the wrist joint angle of the 3D hand model could be controlled by standard variation of 3[deg] or less.

  14. Evaluation of Grasping Motion Using a Virtual Prosthetic Control System

    Science.gov (United States)

    Fukuda, Osamu; Bu, Nan; Ueno, Naohiro

    Electromyogram (EMG) signals can be measured from human muscles and can be used to anticipate movements. In fact, many researchers have tried to use these signals as an interface tool for a prosthetic hand. However, most of these studies focused on the discrimination performance of the EMG signals, and only discussed the control method for the prosthetic hand. Evaluation of the operating performance was seldom reported. This paper proposes a virtual prosthetic control system and presents the analyses of a grasp motion under two different EMG control methods: on/off control and proportional control. The proportional control is able to proportionally control the grasping velocity based on the amplitude of the EMG signal. The on/off control controls the hand at a uniform rate while the amplitude of the EMG signal is greater than a predefined threshold. We conducted experiments with five subjects, and confirmed the usefulness of the developed system.

  15. Early visually evoked electrophysiological responses over the human brain (P1, N170 show stable patterns of face-sensitivity from 4 years to adulthood

    Directory of Open Access Journals (Sweden)

    Dana Kuefner

    2010-01-01

    Full Text Available Whether the development of face recognition abilities truly reflects changes in how faces, specifically, are perceived, or rather can be attributed to more general perceptual or cognitive development is debated. Event-related potential (ERP recordings on the scalp offer promise for this issue because they allow brain responses to complex visual stimuli to be relatively well isolated from other sensory, cognitive and motor processes. ERP studies in 5-16 year-old children report large age-related changes in amplitude, latency (decreases and topographical distribution of the early visual components, the P1 and the occipito-temporal N170. To test the face specificity of these effects, we recorded high-density ERPs to pictures of faces, cars, and their phase-scrambled versions from 72 children between the ages of 4 and 17, and a group of adults. We found that none of the previously reported age-dependent changes in amplitude, latency or topography of the P1 or N170 were specific to faces. Most importantly, when we controlled for age-related variations of the P1, the N170 appeared remarkably similar in amplitude and topography across development, with much smaller age-related decreases in latencies than previously reported. At all ages the N170 showed equivalent face-sensitivity: it had the same topography and right hemisphere dominance, it was absent for meaningless (scrambled stimuli, and larger and earlier for faces than cars. The data also illustrate the large amount of inter-individual and inter-trial variance in young children’s data, which causes the N170 to merge with a later component, the N250 in grand-averaged data. Based on our observations, we suggest that the previously reported “bi-fid” N170 of young children is in fact the N250. Overall, our data indicate that the electrophysiological markers of face-sensitive perceptual processes are present from 4 years of age and do not appear to change throughout development.

  16. Uncemented allograft-prosthetic composite reconstruction of the proximal femur

    Directory of Open Access Journals (Sweden)

    Li Min

    2014-01-01

    Full Text Available Background: Allograft-prosthetic composite can be divided into three groups names cemented, uncemented, and partially cemented. Previous studies have mainly reported outcomes in cemented and partially cemented allograft-prosthetic composites, but have rarely focused on the uncemented allograft-prosthetic composites. The objectives of our study were to describe a surgical technique for using proximal femoral uncemented allograft-prosthetic composite and to present the radiographic and clinical results. Materials and Methods: Twelve patients who underwent uncemented allograft-prosthetic composite reconstruction of the proximal femur after bone tumor resection were retrospectively evaluated at an average followup of 24.0 months. Clinical records and radiographs were evaluated. Results: In our series, union occurred in all the patients (100%; range 5-9 months. Until the most recent followup, there were no cases with infection, nonunion of the greater trochanter, junctional bone resorption, dislocation, allergic reaction, wear of acetabulum socket, recurrence, and metastasis. But there were three periprosthetic fractures which were fixed using cerclage wire during surgery. Five cases had bone resorption in and around the greater trochanter. The average Musculoskeletal Tumor Society (MSTS score and Harris hip score (HHS were 26.2 points (range 24-29 points and 80.6 points (range 66.2-92.7 points, respectively. Conclusions: These results showed that uncemented allograft-prosthetic composite could promote bone union through compression at the host-allograft junction and is a good choice for proximal femoral resection. Although this technology has its own merits, long term outcomes are yet not validated.

  17. Reconsidering evidence-based practice in prosthetic rehabilitation : a shared enterprise

    NARCIS (Netherlands)

    van Twillert, S.; Geertzen, J.; Hemminga, T.; Postema, K.; Lettinga, A.

    2013-01-01

    Background: A divide is experienced between producers and users of evidence in prosthetic rehabilitation. Objective: To discuss the complexity inherent in establishing evidence-based practice in a prosthetic rehabilitation team illustrated by the case of prosthetic prescription for elderly dysvascul

  18. 77 FR 23810 - Advisory Committee on Prosthetics and Special-Disabilities Programs, Notice of Meeting

    Science.gov (United States)

    2012-04-20

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs, Notice of Meeting The...) that a meeting of the Federal Advisory Committee on Prosthetics and Special-Disabilities Programs will... the Secretary of Veterans Affairs on VA's prosthetics programs designed to provide state-of-the-...

  19. 75 FR 65060 - Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2010-10-21

    ... AFFAIRS Advisory Committee on Prosthetics and Special-Disabilities Programs; Notice of Meeting The...) that a meeting of the Advisory Committee on Prosthetics and Special-Disabilities Programs will be held... advise the Secretary of Veterans Affairs on VA's prosthetics programs designed to provide...

  20. 75 FR 24775 - Advisory Committee on Prosthetics and Special Disabilities Programs; Notice of Meeting

    Science.gov (United States)

    2010-05-05

    ... AFFAIRS Advisory Committee on Prosthetics and Special Disabilities Programs; Notice of Meeting The...) that a meeting of the Advisory Committee on Prosthetics and Special Disabilities Programs (the... Secretary of Veterans Affairs on VA's prosthetic programs designed to provide state-of-the- art...

  1. Visual performance with changes in eccentricity in PROSE device: a case report.

    Science.gov (United States)

    Jagadeesh, Divya; Mahadevan, Rajeswari

    2014-01-01

    This case report describes the variations in visual performance of a subject with moderate keratoconus with changes in front surface eccentricities (FSEs) of PROSE (Prosthetic Replacement of Ocular Surface Ecosystem). PROSE device of 0.6 FSE provided maximum visual improvement and reduction in Higher Order Aberrations (HOAs) compared to 0, 0.3 and 0.8 FSEs in this clinical condition.

  2. Patient-Specific Prosthetic Fingers by Remote Collaboration - A Case Study

    CERN Document Server

    Cabibihan, John-John

    2011-01-01

    The concealment of amputation through prosthesis usage can shield an amputee from social stigma and help improve the emotional healing process especially at the early stages of hand or finger loss. However, the traditional techniques in prosthesis fabrication defy this as the patients need numerous visits to the clinics for measurements, fitting and follow-ups. This paper presents a method for constructing a prosthetic finger through online collaboration with the designer. The main input from the amputee comes from the Computer Tomography (CT) data in the region of the affected and the non-affected fingers. These data are sent over the internet and the prosthesis is constructed using visualization, computer-aided design and manufacturing tools. The finished product is then shipped to the patient. A case study with a single patient having an amputated ring finger at the proximal interphalangeal joint shows that the proposed method has a potential to address the patient's psychosocial concerns and minimize the ...

  3. Characterization of microbes in prosthetic joint specimens by culture-independent molecular methods

    DEFF Research Database (Denmark)

    Xu, Yijuan; Rudkjøbing, Vibeke Børsholt; Simonsen, Ole

    was to investigate the microbial diversity in surgical samples (eg. synovial fluid, periprosthetic tissue, removed prosthesis) from 22 prosthetic patients using a range of culture-independent molecular methods including broad range 16S rRNA gene PCR, cloning, phylogeny, quantitative PCR (qPCR), and fluorescence...... in situ hybridization (FISH). Concomitant samples were cultured by standard methods. Overall, the results of culture-based and molecular methods showed concordant results for 13 patients and discrepant results for 6 patients. In the remaining cases, culture methods identified one species or a group...... approach, and FISH and confocal scanning laser microscopy visualized the presence of both single cells and microcolonies. In conclusion, cultureindependent methods identified more species and more polymicrobial infections than standard culturebased methods. Little is presently known about the pathogenesis...

  4. ALL-CERAMIC APPLIANCES FOR PROSTHETIC REHABILITATION IN YOUNG PATIENTS

    Directory of Open Access Journals (Sweden)

    Alexandru BASNO

    2016-03-01

    Full Text Available The aim of the present study was to assess a possible fixed rehabilitation in young patients, by means of CAD-CAM techniques. Materials and method. The CERCON substractive technique with zirconium oxide blanks was applied. Discussion. The obtained prosthetic structures are characterized by a better aesthetic integration, optimum marginal adaptation and suitable clinical longevity. Conclusions. All-ceramic prostheses appear as a biological solution in the prosthetic rehabilitation of young patients, as they require reduced removal of both enamel and dentin, while obeying the biological conservative principle of treatment.

  5. A hybrid adaptive control strategy for a smart prosthetic hand.

    Science.gov (United States)

    Chen, Cheng-Hung; Naidu, D Subbaram; Perez-Gracia, Alba; Schoen, Marco P

    2009-01-01

    This paper presents a hybrid of a soft computing technique of adaptive neuro-fuzzy inference system (ANFIS) and a hard computing technique of adaptive control for a two-dimensional movement of a prosthetic hand with a thumb and index finger. In particular, ANFIS is used for inverse kinematics, and the adaptive control is used for linearized dynamics to minimize tracking error. The simulations of this hybrid controller, when compared with the proportional-integral-derivative (PID) controller showed enhanced performance. Work is in progress to extend this methodology to a five-fingered, three-dimensional prosthetic hand.

  6. Advances in the diagnosis and treatment of vestibular disorders: psychophysics and prosthetics.

    Science.gov (United States)

    Lewis, Richard F

    2015-04-01

    Although vestibular disorders are common and often disabling, they remain difficult to diagnose and treat. For these reasons, considerable interest has been focused on developing new ways to identify peripheral and central vestibular abnormalities and on new therapeutic options that could benefit the numerous patients who remain symptomatic despite optimal therapy. In this review, I focus on the potential utility of psychophysical vestibular testing and vestibular prosthetics. The former offers a new diagnostic approach that may prove to be superior to the current tests in some circumstances; the latter may be a way to provide the brain with information about head motion that restores some elements of the information normally provided by the vestibular labyrinth.

  7. Toxicology of antimicrobial nanoparticlesfor prosthetic devices

    Directory of Open Access Journals (Sweden)

    Nuñez-Anita RE

    2014-08-01

    Full Text Available Rosa Elvira Nuñez-Anita,1 Laura Susana Acosta-Torres,2 Jorge Vilar-Pineda,2 Juan Carlos Martínez-Espinosa,3 Javier de la Fuente-Hernández, 2 Víctor Manuel Castaño4 1Facultad de Medicina Veterinariay Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Tarìmbaro Municipio de Morelia, Michoacán, México; 2Escuela Nacionalde Estudios Superiores, Universidad Nacional Autónoma de México, Unidad León, Leòn Guanajuato, México; 3Unidad Profesional Interdisciplinaria de Ingenieria Campus Guanajuato, Instituto Politécnico Nacional, Leòn Guanajuato, México; 4Departamento de Materiales Moleculares, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Querètaro, México Abstract: Advances in nanotechnology are producing an accelerated proliferation of new nanomaterial composites that are likely to become an important source of engineered health-related products. Nanoparticles with antifungal effects are of great interest in the formulation of microbicidal materials. Fungi are found as innocuous commensals and colonize various habitats in and on humans, especially the skin and mucosa. As growth on surfaces is a natural part of the Candida spp. lifestyle, one can expect that Candida organisms colonize prosthetic devices, such as dentures. Macromolecular systems, due to their properties, allow efficient use of these materials in various fields, including the creation of reinforced nanoparticle polymers with antimicrobial activity. This review briefly summarizes the results of studies conducted during the past decade and especially in the last few years focused on the toxicity of different antimicrobial polymers and factors influencing their activities, as well as the main applications of antimicrobial polymers in dentistry. The present study addresses aspects that are often overlooked in nanotoxicology studies, such as careful time-dependent characterization of agglomeration

  8. Dental prosthetic status and prosthetic needs of institutionalised elderly population in oldage homes of jabalpur city, madhya pradesh, India.

    Science.gov (United States)

    Deogade, Suryakant C; Vinay, S; Naidu, Sonal

    2013-12-01

    Oral disorders are cumulative throughout life and hence unfavourable outcomes are likely to be greatest among the elderly. A descriptive cross-sectional study was conducted among institutionalized geriatric population in old-age homes of Jabalpur city, Madhya Pradesh, to assess their prosthetic status and prosthetic needs. A cross-sectional survey was conducted in all the four old-age homes of Jabalpur city, Madhya Pradesh state, India. All residents aged 60 years and above formed the study population. The recording of prosthetic status and prosthetic needs was carried out according to the World Health Organisation (WHO) Oral Health Assessment Form (1997). A total of 224 individuals were included in the study of which 123 were females and 101 were males. Seventy five percent of the females and 55 % of the males had no prostheses in their upper arch and 61 % of the females and 76 % of the males had no prostheses in their lower arch. More number of males presented with 'Bridges' in their upper arch when compared to females (P value = 0.006). Highest prosthetic need in males was multi-unit prosthesis (42 % in upper arch and 41 % in lower arch) whereas, females' required full prosthesis (39 % in both the upper arch and lower arches). Ageing presents some formidable challenges, particularly with the institutionalised. This study clearly demonstrates a high insufficiency of prosthetic care among the institutionalized elderly population. Any preparation towards the provision of oral health care should not be limited to treatment alone but, more importantly focus on empowering this elderly community with information and education programmes.

  9. Design and Implementation of Prosthetic Arm using Gear Motor Control Technique with Appropriate Testing

    CERN Document Server

    Neogi, Biswarup; Ghosal, Soumya; Das, Achintya; Tibarewala, D N

    2011-01-01

    Any part of the human body replication procedure commences the prosthetic control science. This paper highlights the hardware design technique of a prosthetic arm with implementation of gear motor control aspect. The prosthetic control arm movement has been demonstrated in this paper applying processor programming and with the successful testing of the designed prosthetic model. The architectural design of the prosthetic arm here has been replaced by lighter material instead of heavy metal, as well as the traditional EMG (electro myographic) signal has been replaced by the muscle strain.

  10. Smart Prosthetic Hand Technology - Phase 2

    Science.gov (United States)

    2011-05-01

    involves flexion, abduction, and medial rotation of the thumb so that the pulp surface can make contact with the terminal phalanges of one or all of the...in Cu are oysters, beef or lamb liver, Brazil nuts, cocoa, black pepper, lobster, sunflower seeds, green olives , avocados, and wheat bran. The...red meat, fish, poultry , beans, vegetables, black-eye peas, wheat, and cereals. Page 481 of 531 Fe is another extensively studied metal in brain

  11. Prosthetic Valve Endocarditis: A Complication of Spinal Epidural Abscess

    Directory of Open Access Journals (Sweden)

    Armando Bedoya

    2010-01-01

    Full Text Available Epidural injections for chronic low back pain are controversial, and their effectiveness is debated. Although epidural injections are considered a minor procedure with low morbidity, catastrophic complications may occur. We describe a case of prosthetic valve endocarditis secondary to an epidural abscess after epidural injection to alert clinicians to this unusual association.

  12. Prosthetic Valve Endocarditis: A Complication of Spinal Epidural Abscess

    OpenAIRE

    Bedoya, Armando; Gentilesco, Bethany

    2010-01-01

    Epidural injections for chronic low back pain are controversial, and their effectiveness is debated. Although epidural injections are considered a minor procedure with low morbidity, catastrophic complications may occur. We describe a case of prosthetic valve endocarditis secondary to an epidural abscess after epidural injection to alert clinicians to this unusual association.

  13. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Science.gov (United States)

    2010-04-01

    ... intended for medical purposes to support, protect, or aid in the use of a cast, orthosis (brace), or prosthesis. Examples of prosthetic and orthotic accessories include the following: A pelvic support band and belt, a cast shoe, a cast bandage, a limb cover, a prosthesis alignment device, a postsurgical pylon,...

  14. Selective criteria for successful long-term prosthetic use.

    Science.gov (United States)

    Mueller, M J; Delitto, A

    1985-07-01

    The purpose of this study was to identify criteria contributing to successful long-term prosthetic use in patients with an amputation secondary to vascular disease. All elderly patients with a unilateral below-knee amputation or an above-knee amputation, secondary to vascular disease, seen in our clinic between 1977 and 1982 were included in this telephone survey. Of those contacted, 37 of 38 below-knee amputees (BKAs) and 7 of 18 above-knee amputees (AKAs) still wore their prostheses at least part of every day (success). We used a two-tailed chi-square to compare the success of the BKAs with the success of the AKAs. The BKAs were successful more often (X2 = 24.81, df = 1, p less than .001). All AKAs also were characterized according to age, time from prescription, obesity, ambulatory status, strength, range of motion, sex, general compliance, and medical problems after prosthetic prescription. Of these criteria, only compliance and medical problems after prescription showed a significant difference between successful and nonsuccessful long-term AKA prosthetic users (X2 = 5.76, df = 1, p less than .05 for each criterion). As the demands of quality assurance and diagnostic related groupings increase, these results can assist the physical therapy clinician in setting realistic goals for the geriatric amputee and help predict if the patient will be a successful prosthetic user.

  15. Prosthetic arm monitoring system using a programmable interface controller.

    Science.gov (United States)

    Denaro, B A; Schoenberg, J S; Self, B P; Bagley, A

    2001-01-01

    Children with upper extremity limb deficiency are often prescribed a prosthetic arm to assist with daily function. Three types of prostheses are available: passive, active body-powered, and active myoelectric; costs range from $3,000 to $15,000. Clinicians rely on parent and child feedback regarding the usefulness of the prosthesis, and may assess the child's skill in using the device in a controlled setting. However, these methods do not provide an objective quantification of the wear and use of the device during daily activities. The purpose of this project is to develop a sensor to record the amount of time per day the prosthetic arm is worn, and to count the number of times per day the child activates (closes) the prosthetic hand (or terminal device). The system that has been developed can be integrated unobtrusively into a child's prosthetic arm. A programmable interface controller (PIC) with interface circuitry and memory was developed to record the daily wear pattern and hand usage of the prosthesis at 15-minute intervals. Memory and battery capacities are sufficient to record data over a three-month period. A personal computer interface downloads the collected data and may be used to reprogram the device for different time periods of data collection. All components, including the battery, have a mass of 87 grams and fit inside the forearm cavity of a 9-year old's prosthesis. Controlled trials are underway at Shriners Hospital for Children, Northern California, to determine system reliability.

  16. Specialisation and specialist education in prosthetic dentistry in Europe

    NARCIS (Netherlands)

    Owall, B.; Welfare, R.; Garefis, P.; Hedzelek, W.; Hobkirk, J.; Isidor, F.; Jerolimov, V.; Jokstad, A.; Kalk, W.; Kronstrom, M.; van der Kuij, P.; Mericske-Stern, R.; Naert, I.; Narhi, T.; Nilner, K.; Polyzois, G.; Setz, J.; User, A.; Zonnenberg, A.

    2006-01-01

    This presentation reports on the results of a meeting of prosthodontists from selected European countries. The aim of the meeting was to analyse and promote specialisation and specialist education in Prosthetic Dentistry in Europe. Representatives for Europe were selected from the European Prosthodo

  17. PROSTHETIC GAIT OF UNILATERAL TRANSFEMORAL AMPUTEES - A KINEMATIC STUDY

    NARCIS (Netherlands)

    JAEGERS, SMHJ; ARENDZEN, JH; DEJONGH, HJ

    1995-01-01

    Objective: The prosthetic gait of unilateral transfemoral amputees. Design: Case series. Setting: Laboratory of Gait Analysis (GIGA-system of K-lab) in the Department of Rehabilitation of a university hospital. Patients: Eleven men with transfemoral amputation (mean age 35.7 years) participated. The

  18. Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

    NARCIS (Netherlands)

    Habets, Jesse; Budde, Ricardo P.; Symersky, Petr; van den Brink, Renee B.; de Mol, Bas A.; Mali, Willem P.; van Herwerden, Lex A.; Chamuleau, Steven A.

    2011-01-01

    Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniq

  19. Predictors of Success on the Prosthetics Certification Examination

    Science.gov (United States)

    Miro, Rebecca Maria

    2014-01-01

    Students who graduate from a practitioner program in prosthetics & orthotics must achieve certification in order to obtain licensure and practice independently in 16 states. In states where licensure is not mandatory, graduates may choose to pursue certification in order assure patients that they are practicing at the highest level as well as…

  20. Development of a prototype over-actuated biomimetic prosthetic hand.

    Directory of Open Access Journals (Sweden)

    Matthew R Williams

    Full Text Available The loss of a hand can greatly affect quality of life. A prosthetic device that can mimic normal hand function is very important to physical and mental recuperation after hand amputation, but the currently available prosthetics do not fully meet the needs of the amputee community. Most prosthetic hands are not dexterous enough to grasp a variety of shaped objects, and those that are tend to be heavy, leading to discomfort while wearing the device. In order to attempt to better simulate human hand function, a dexterous hand was developed that uses an over-actuated mechanism to form grasp shape using intrinsic joint mounted motors in addition to a finger tendon to produce large flexion force for a tight grip. This novel actuation method allows the hand to use small actuators for grip shape formation, and the tendon to produce high grip strength. The hand was capable of producing fingertip flexion force suitable for most activities of daily living. In addition, it was able to produce a range of grasp shapes with natural, independent finger motion, and appearance similar to that of a human hand. The hand also had a mass distribution more similar to a natural forearm and hand compared to contemporary prosthetics due to the more proximal location of the heavier components of the system. This paper describes the design of the hand and controller, as well as the test results.