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Sample records for neural mechanisms supporting

  1. Distinctive neural mechanisms supporting visual object individuation and identification.

    Science.gov (United States)

    Xu, Yaoda

    2009-03-01

    Many everyday activities, such as driving on a busy street, require the encoding of distinctive visual objects from crowded scenes. Given resource limitations of our visual system, one solution to this difficult and challenging task is to first select individual objects from a crowded scene (object individuation) and then encode their details (object identification). Using functional magnetic resonance imaging, two distinctive brain mechanisms were recently identified that support these two stages of visual object processing. While the inferior intraparietal sulcus (IPS) selects a fixed number of about four objects via their spatial locations, the superior IPS and the lateral occipital complex (LOC) encode the features of a subset of the selected objects in great detail (object shapes in this case). Thus, the inferior IPS individuates visual objects from a crowded display and the superior IPS and higher visual areas participate in subsequent object identification. Consistent with the prediction of this theory, even when only object shape identity but not its location is task relevant, this study shows that object individuation in the inferior IPS treats four identical objects similarly as four objects that are all different, whereas object shape identification in the superior IPS and the LOC treat four identical objects as a single unique object. These results provide independent confirmation supporting the dissociation between visual object individuation and identification in the brain.

  2. Challenges for identifying the neural mechanisms that support spatial navigation: the impact of spatial scale

    Directory of Open Access Journals (Sweden)

    Thomas eWolbers

    2014-08-01

    Full Text Available Spatial navigation is a fascinating behavior that is essential for our everyday lives. It involves nearly all sensory systems, it requires numerous parallel computations, and it engages multiple memory systems. One of the key problems in this field pertains to the question of reference frames: spatial information such as direction or distance can be coded egocentrically - relative to an observer - or allocentrically - in a reference frame independent of the observer. While many studies have associated striatal and parietal circuits with egocentric coding and entorhinal/hippocampal circuits with allocentric coding, this strict dissociation is not in line with a growing body of experimental data. In this review, we discuss some of the problems that can arise when studying the neural mechanisms that are presumed to support different spatial reference frames. We argue that the scale of space in which a navigation task takes place plays a crucial role in determining the processes that are being recruited. This has important implications, particularly for the inferences that can be made from animal studies in small scale space about the neural mechanisms supporting human spatial navigation in large (environmental spaces. Furthermore, we argue that many of the commonly used tasks to study spatial navigation and the underlying neuronal mechanisms involve different types of reference frames, which can complicate the interpretation of neurophysiological data.

  3. Neural mechanisms supporting the extraction of general knowledge across episodic memories

    NARCIS (Netherlands)

    Sweegers, C.C.; Takashima, A.; Fernandez, G.S.E.; Talamini, L.M.

    2014-01-01

    General knowledge acquisition entails the extraction of statistical regularities from the environment. At high levels of complexity, this may involve the extraction, and consolidation, of associative regularities across event memories. The underlying neural mechanisms would likely involve a

  4. Neural mechanisms supporting the extraction of general knowledge across episodic memories.

    Science.gov (United States)

    Sweegers, Carly C G; Takashima, Atsuko; Fernández, Guillén; Talamini, Lucia M

    2014-02-15

    General knowledge acquisition entails the extraction of statistical regularities from the environment. At high levels of complexity, this may involve the extraction, and consolidation, of associative regularities across event memories. The underlying neural mechanisms would likely involve a hippocampo-neocortical dialog, as proposed previously for system-level consolidation. To test these hypotheses, we assessed possible differences in consolidation between associative memories containing cross-episodic regularities and unique associative memories. Subjects learned face-location associations, half of which responded to complex regularities regarding the combination of facial features and locations, whereas the other half did not. Importantly, regularities could only be extracted over hippocampus-encoded, associative aspects of the items. Memory was assessed both immediately after encoding and 48 h later, under fMRI acquisition. Our results suggest that processes related to system-level reorganization occur preferentially for regular associations across episodes. Moreover, the build-up of general knowledge regarding regular associations appears to involve the coordinated activity of the hippocampus and mediofrontal regions. The putative cross-talk between these two regions might support a mechanism for regularity extraction. These findings suggest that the consolidation of cross-episodic regularities may be a key mechanism underlying general knowledge acquisition. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. COMT val158met genotype affects recruitment of neural mechanisms supporting fluid intelligence.

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    Bishop, Sonia J; Fossella, John; Croucher, Camilla J; Duncan, John

    2008-09-01

    Fluid intelligence (g(f)) influences performance across many cognitive domains. It is affected by both genetic and environmental factors. Tasks tapping g(f) activate a network of brain regions including the lateral prefrontal cortex (LPFC), the presupplementary motor area/anterior cingulate cortex (pre-SMA/ACC), and the intraparietal sulcus (IPS). In line with the "intermediate phenotype" approach, we assessed effects of a polymorphism (val(158)met) in the catechol-O-methyltransferase (COMT) gene on activity within this network and on actual task performance during spatial and verbal g(f) tasks. COMT regulates catecholaminergic signaling in prefrontal cortex. The val(158) allele is associated with higher COMT activity than the met(158) allele. Twenty-two volunteers genotyped for the COMT val(158)met polymorphism completed high and low g(f) versions of spatial and verbal problem-solving tasks. Our results showed a positive effect of COMT val allele load upon the blood oxygen level-dependent response in LPFC, pre-SMA/ACC, and IPS during high g(f) versus low g(f) task performance in both spatial and verbal domains. These results indicate an influence of the COMT val(158)met polymorphism upon the neural circuitry supporting g(f). The behavioral effects of val allele load differed inside and outside the scanner, consistent with contextual modulation of the relation between COMT val(158)met genotype and g(f) task performance.

  6. Neural mechanisms for voice recognition

    NARCIS (Netherlands)

    Andics, A.V.; McQueen, J.M.; Petersson, K.M.; Gal, V.; Rudas, G.; Vidnyanszky, Z.

    2010-01-01

    We investigated neural mechanisms that support voice recognition in a training paradigm with fMRI. The same listeners were trained on different weeks to categorize the mid-regions of voice-morph continua as an individual's voice. Stimuli implicitly defined a voice-acoustics space, and training

  7. Evaluating the negative or valuing the positive? Neural mechanisms supporting feedback-based learning across development

    NARCIS (Netherlands)

    van Duijvenvoorde, A.C.K.; Zanolie, K.; Rombouts, S.A.R.B.; Raijmakers, M.E.J.; Crone, E.A.

    2008-01-01

    Howchildren learn from positive and negative performance feedback lies at the foundation of successful learning and is therefore of great importance for educational practice. In this study, we used functional magnetic resonance imaging (fMRI) to examine the neural developmental changes related to

  8. Evaluating the negative or valuing the positive? Neural mechanisms supporting feedback-based learning across development

    NARCIS (Netherlands)

    A.C.K. van Duijvenvoorde (Anna C.); K. Zanolie (Kiki); S.A.R.B. Rombouts (Serge); M.E.J. Raijmakers (Maartje E.); E.A. Crone (Eveline)

    2008-01-01

    textabstractHow children learn from positive and negative performance feedback lies at the foundation of successful learning and is therefore of great importance for educational practice. In this study, we used functional magnetic resonance imaging (fMRI) to examine the neural developmental changes

  9. The Neural Support Vector Machine

    NARCIS (Netherlands)

    Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus

    2013-01-01

    This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a

  10. Evaluating the negative or valuing the positive? Neural mechanisms supporting feedback-based learning across development.

    Science.gov (United States)

    van Duijvenvoorde, Anna C K; Zanolie, Kiki; Rombouts, Serge A R B; Raijmakers, Maartje E J; Crone, Eveline A

    2008-09-17

    How children learn from positive and negative performance feedback lies at the foundation of successful learning and is therefore of great importance for educational practice. In this study, we used functional magnetic resonance imaging (fMRI) to examine the neural developmental changes related to feedback-based learning when performing a rule search and application task. Behavioral results from three age groups (8-9, 11-13, and 18-25 years of age) demonstrated that, compared with adults, 8- to 9-year-old children performed disproportionally more inaccurately after receiving negative feedback relative to positive feedback. Additionally, imaging data pointed toward a qualitative difference in how children and adults use performance feedback. That is, dorsolateral prefrontal cortex and superior parietal cortex were more active after negative feedback for adults, but after positive feedback for children (8-9 years of age). For 11- to 13-year-olds, these regions did not show differential feedback sensitivity, suggesting that the transition occurs around this age. Pre-supplementary motor area/anterior cingulate cortex, in contrast, was more active after negative feedback in both 11- to 13-year-olds and adults, but not 8- to 9-year-olds. Together, the current data show that cognitive control areas are differentially engaged during feedback-based learning across development. Adults engage these regions after signals of response adjustment (i.e., negative feedback). Young children engage these regions after signals of response continuation (i.e., positive feedback). The neural activation patterns found in 11- to 13-year-olds indicate a transition around this age toward an increased influence of negative feedback on performance adjustment. This is the first developmental fMRI study to compare qualitative changes in brain activation during feedback learning across distinct stages of development.

  11. [Neural mechanisms of mastication].

    Science.gov (United States)

    Inoue, Tomio

    2015-02-01

    Abstract Comminution of food by mastication contributes to an increase in the efficiency of energy intake from food, which supports the high metabolic rate of mammals. The central pattern-generating circuit for mastication produces motor commands for mastication by using sensory information from periodontal mechanoreceptors and muscle spindles in the jaw-closing muscles. The motor commands that are glutamatergic, glycinergic, and GABAergic are transmitted to motoneurons for the jaw, tongue, etc., through premotor neurons that are located in the supratrigeminal region, reticular formation dorsal to the facial nucleus, etc. Our previous studies of N-methyl-D-aspartate-induced fictive suckling using isolated brainstem-spinal cord preparations obtained from neonatal mice revealed that the neuronal network that contributes to the synchronized activity of the jaw and tongue muscles is located in both the right and left sides. The network of either side sends its command to the trigeminal motoneurons mainly via the commissural pathway, while the command is sent to the hypoglossal motoneurons on the same side.

  12. [Neural mechanism of blindsight].

    Science.gov (United States)

    Yoshida, Masatoshi

    2013-06-01

    "Blindsight" is a phenomenon whereby hemianopic patients with damage in the primary visual cortex (V1) are able to process visual information in their blind visual field. Two pathways that bypass the V1 may be responsible for this residual vision. The first pathway is the retinotectal pathway in which the superior colliculus in the midbrain receives direct retinal signals and sends them to the extrastriate cortex via the pulvinar. The second pathway is the geniculo-extrastriate pathway in which direct retinal input to the lateral geniculate nucleus is sent straight to the extrastriate cortex. Herein, I summarize evidence supporting the involvement of either pathway. The evidence was obtained from anatomical, neurophysiological, imaging, and behavioral studies carried out on macaque monkeys and humans. I emphasize three points: 1) crosstalk exists between the retinotectal pathway and the geniculo-extrastriate pathway, that is, the projection from the superficial layer of the superior colliculus to the koniocellular layer of the lateral geniculate nucleus; 2) three visual channels (the luminance in the magnocellular pathway, the red-green opponency in the parvocellular pathway, and the blue-yellow opponency in the koniocellular pathway) are not independent, as previously assumed; and 3) a global reorganization in the brain circuit occurs following the lesions of the V1 and subsequent recovery. Finally, I introduce a recent study that employed a saliency computational model to quantitatively evaluate the residual visual channels in blindsight monkeys during free-viewing behavior. Their findings suggest that plastic changes occur in the color-processing pathways.

  13. Neural mechanisms of social dominance

    Directory of Open Access Journals (Sweden)

    Noriya eWatanabe

    2015-06-01

    Full Text Available In a group setting, individuals’ perceptions of their own level of dominance or of the dominance level of others, and the ability to adequately control their behavior based on these perceptions are crucial for living within a social environment. Recent advances in neural imaging and molecular technology have enabled researchers to investigate the neural substrates that support the perception of social dominance and the formation of a social hierarchy in humans. At the systems’ level, recent studies showed that dominance perception is represented in broad brain regions which include the amygdala, hippocampus, striatum, and various cortical networks such as the prefrontal, and parietal cortices. Additionally, neurotransmitter systems such as the dopaminergic and serotonergic systems, modulate and are modulated by the formation of the social hierarchy in a group. While these monoamine systems have a wide distribution and multiple functions, it was recently found that the Neuropeptide B/W contributes to the perception of dominance and is present in neurons that have a limited projection primarily to the amygdala. The present review discusses the specific roles of these neural regions and neurotransmitter systems in the perception of dominance and in hierarchy formation.

  14. Deciphering the Cognitive and Neural Mechanisms Underlying ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Deciphering the Cognitive and Neural Mechanisms Underlying Auditory Learning. This project seeks to understand the brain mechanisms necessary for people to learn to perceive sounds. Neural circuits and learning. The research team will test people with and without musical training to evaluate their capacity to learn ...

  15. Artificial neural networks and support vector mac

    Indian Academy of Sciences (India)

    Quantitative structure-property relationships of electroluminescent materials: Artificial neural networks and support vector machines to predict electroluminescence of organic molecules. ALANA FERNANDES GOLIN and RICARDO STEFANI. ∗. Laboratório de Estudos de Materiais (LEMAT), Instituto de Ciências Exatas e da ...

  16. Neural Mechanisms of Conceptual Relations

    Science.gov (United States)

    Lewis, Gwyneth A.

    2017-01-01

    An over-arching goal in neurolinguistic research is to characterize the neural bases of semantic representation. A particularly relevant goal concerns whether we represent features and events (a) together in a generalized semantic hub or (b) separately in distinct but complementary systems. While the left anterior temporal lobe (ATL) is strongly…

  17. Language and Cognition Interaction Neural Mechanisms

    Science.gov (United States)

    2011-06-01

    2007. [72] L. I. Perlovsky, “Symbols: integrated cognition and language ,” in Semiotics and Intelligent Systems Development, R. Gudwin and J. Queiroz...Article Language and Cognition Interaction Neural Mechanisms Leonid Perlovsky Harvard University and Air Force Research Laboratory, Harvard University...Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How language

  18. Reject mechanisms for massively parallel neural network character recognition systems

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    Garris, Michael D.; Wilson, Charles L.

    1992-12-01

    Two reject mechanisms are compared using a massively parallel character recognition system implemented at NIST. The recognition system was designed to study the feasibility of automatically recognizing hand-printed text in a loosely constrained environment. The first method is a simple scalar threshold on the output activation of the winning neurode from the character classifier network. The second method uses an additional neural network trained on all outputs from the character classifier network to accept or reject assigned classifications. The neural network rejection method was expected to perform with greater accuracy than the scalar threshold method, but this was not supported by the test results presented. The scalar threshold method, even though arbitrary, is shown to be a viable reject mechanism for use with neural network character classifiers. Upon studying the performance of the neural network rejection method, analyses show that the two neural networks, the character classifier network and the rejection network, perform very similarly. This can be explained by the strong non-linear function of the character classifier network which effectively removes most of the correlation between character accuracy and all activations other than the winning activation. This suggests that any effective rejection network must receive information from the system which has not been filtered through the non-linear classifier.

  19. Neural mechanisms of hypnosis and meditation.

    Science.gov (United States)

    De Benedittis, Giuseppe

    2015-12-01

    Hypnosis has been an elusive concept for science for a long time. However, the explosive advances in neuroscience in the last few decades have provided a "bridge of understanding" between classical neurophysiological studies and psychophysiological studies. These studies have shed new light on the neural basis of the hypnotic experience. Furthermore, an ambitious new area of research is focusing on mapping the core processes of psychotherapy and the neurobiology/underlying them. Hypnosis research offers powerful techniques to isolate psychological processes in ways that allow their neural bases to be mapped. The Hypnotic Brain can serve as a way to tap neurocognitive questions and our cognitive assays can in turn shed new light on the neural bases of hypnosis. This cross-talk should enhance research and clinical applications. An increasing body of evidence provides insight in the neural mechanisms of the Meditative Brain. Discrete meditative styles are likely to target different neurodynamic patterns. Recent findings emphasize increased attentional resources activating the attentional and salience networks with coherent perception. Cognitive and emotional equanimity gives rise to an eudaimonic state, made of calm, resilience and stability, readiness to express compassion and empathy, a main goal of Buddhist practices. Structural changes in gray matter of key areas of the brain involved in learning processes suggest that these skills can be learned through practice. Hypnosis and Meditation represent two important, historical and influential landmarks of Western and Eastern civilization and culture respectively. Neuroscience has beginning to provide a better understanding of the mechanisms of both Hypnotic and Meditative Brain, outlining similarities but also differences between the two states and processes. It is important not to view either the Eastern or the Western system as superior to the other. Cross-fertilization of the ancient Eastern meditation techniques

  20. Neural circuit mechanisms of posttraumatic epilepsy

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    Robert F Hunt

    2013-06-01

    Full Text Available Traumatic brain injury (TBI greatly increases the risk for a number of mental health problems and is one of the most common causes of medically intractable epilepsy in humans. Several models of TBI have been developed to investigate the relationship between trauma, seizures, and epilepsy-related changes in neural circuit function. These studies have shown that the brain initiates immediate neuronal and glial responses following an injury, usually leading to significant cell loss in areas of the injured brain. Over time, long-term changes in the organization of neural circuits, particularly in neocortex and hippocampus, lead to an imbalance between excitatory and inhibitory neurotransmission and increased risk for spontaneous seizures. These include alterations to inhibitory interneurons and formation of new, excessive recurrent excitatory synaptic connectivity. Here, we review in vivo models of TBI as well as key cellular mechanisms of synaptic reorganization associated with posttraumatic epilepsy. The potential role of inflammation and increased blood brain barrier permeability in the pathophysiology of posttraumatic epilepsy is also discussed. A better understanding of mechanisms that promote the generation of epileptic activity versus those that promote compensatory brain repair and functional recovery should aid development of successful new therapies for posttraumatic epilepsy.

  1. Multiscale Quantum Mechanics/Molecular Mechanics Simulations with Neural Networks.

    Science.gov (United States)

    Shen, Lin; Wu, Jingheng; Yang, Weitao

    2016-10-11

    Molecular dynamics simulation with multiscale quantum mechanics/molecular mechanics (QM/MM) methods is a very powerful tool for understanding the mechanism of chemical and biological processes in solution or enzymes. However, its computational cost can be too high for many biochemical systems because of the large number of ab initio QM calculations. Semiempirical QM/MM simulations have much higher efficiency. Its accuracy can be improved with a correction to reach the ab initio QM/MM level. The computational cost on the ab initio calculation for the correction determines the efficiency. In this paper we developed a neural network method for QM/MM calculation as an extension of the neural-network representation reported by Behler and Parrinello. With this approach, the potential energy of any configuration along the reaction path for a given QM/MM system can be predicted at the ab initio QM/MM level based on the semiempirical QM/MM simulations. We further applied this method to three reactions in water to calculate the free energy changes. The free-energy profile obtained from the semiempirical QM/MM simulation is corrected to the ab initio QM/MM level with the potential energies predicted with the constructed neural network. The results are in excellent accordance with the reference data that are obtained from the ab initio QM/MM molecular dynamics simulation or corrected with direct ab initio QM/MM potential energies. Compared with the correction using direct ab initio QM/MM potential energies, our method shows a speed-up of 1 or 2 orders of magnitude. It demonstrates that the neural network method combined with the semiempirical QM/MM calculation can be an efficient and reliable strategy for chemical reaction simulations.

  2. Neural mechanisms of sequence generation in songbirds

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    Langford, Bruce

    Animal models in research are useful for studying more complex behavior. For example, motor sequence generation of actions requiring good muscle coordination such as writing with a pen, playing an instrument, or speaking, may involve the interaction of many areas in the brain, each a complex system in itself; thus it can be difficult to determine causal relationships between neural behavior and the behavior being studied. Birdsong, however, provides an excellent model behavior for motor sequence learning, memory, and generation. The song consists of learned sequences of notes that are spectrographically stereotyped over multiple renditions of the song, similar to syllables in human speech. The main areas of the songbird brain involve in singing are known, however, the mechanisms by which these systems store and produce song are not well understood. We used a custom built, head-mounted, miniature motorized microdrive to chronically record the neural firing patterns of identified neurons in HVC, a pre-motor cortical nucleus which has been shown to be important in song timing. These were done in Bengalese finch which generate a song made up of stereotyped notes but variable note sequences. We observed song related bursting in neurons projecting to Area X, a homologue to basal ganglia, and tonic firing in HVC interneurons. Interneuron had firing rate patterns that were consistent over multiple renditions of the same note sequence. We also designed and built a light-weight, low-powered wireless programmable neural stimulator using Bluetooth Low Energy Protocol. It was able to generate perturbations in the song when current pulses were administered to RA, which projects to the brainstem nucleus responsible for syringeal muscle control.

  3. Mechanical circulatory support in pediatrics.

    Science.gov (United States)

    Steffen, Robert J; Miletic, Kyle G; Schraufnagel, Dean P; Vargo, Patrick R; Fukamachi, Kiyotaka; Stewart, Robert D; Moazami, Nader

    2016-05-01

    End-stage heart failure affects thousands of children yearly and mechanical circulatory support is used at many points in their care. Extracorporeal membrane oxygenation supports both the failing heart and lungs, which has led to its use as an adjunct to cardiopulmonary resuscitation as well as in post-operative cardiogenic shock. Continuous-flow ventricular assist devices (VAD) have replaced pulsatile-flow devices in adults and early studies have shown promising results in children. The Berlin paracorporeal pulsatile VAD recently gained U.S. Food and Drug Administration approval and remains the only VAD approved in pediatrics. Failing univentricular hearts and other congenitally corrected lesions are new areas for mechanical support. Finding novel uses, improving durability, and minimizing complications are areas of growth in pediatric mechanical circulatory support.

  4. Memory mechanisms supporting syntactic comprehension.

    Science.gov (United States)

    Caplan, David; Waters, Gloria

    2013-04-01

    Efforts to characterize the memory system that supports sentence comprehension have historically drawn extensively on short-term memory as a source of mechanisms that might apply to sentences. The focus of these efforts has changed significantly in the past decade. As a result of changes in models of short-term working memory (ST-WM) and developments in models of sentence comprehension, the effort to relate entire components of an ST-WM system, such as those in the model developed by Baddeley (Nature Reviews Neuroscience 4: 829-839, 2003) to sentence comprehension has largely been replaced by an effort to relate more specific mechanisms found in modern models of ST-WM to memory processes that support one aspect of sentence comprehension--the assignment of syntactic structure (parsing) and its use in determining sentence meaning (interpretation) during sentence comprehension. In this article, we present the historical background to recent studies of the memory mechanisms that support parsing and interpretation and review recent research into this relation. We argue that the results of this research do not converge on a set of mechanisms derived from ST-WM that apply to parsing and interpretation. We argue that the memory mechanisms supporting parsing and interpretation have features that characterize another memory system that has been postulated to account for skilled performance-long-term working memory. We propose a model of the relation of different aspects of parsing and interpretation to ST-WM and long-term working memory.

  5. Neural mechanisms of discourse comprehension: a human lesion study.

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    Barbey, Aron K; Colom, Roberto; Grafman, Jordan

    2014-01-01

    Discourse comprehension is a hallmark of human social behaviour and refers to the act of interpreting a written or spoken message by constructing mental representations that integrate incoming language with prior knowledge and experience. Here, we report a human lesion study (n = 145) that investigates the neural mechanisms underlying discourse comprehension (measured by the Discourse Comprehension Test) and systematically examine its relation to a broad range of psychological factors, including psychometric intelligence (measured by the Wechsler Adult Intelligence Scale), emotional intelligence (measured by the Mayer, Salovey, Caruso Emotional Intelligence Test), and personality traits (measured by the Neuroticism-Extraversion-Openness Personality Inventory). Scores obtained from these factors were submitted to voxel-based lesion-symptom mapping to elucidate their neural substrates. Stepwise regression analyses revealed that working memory and extraversion reliably predict individual differences in discourse comprehension: higher working memory scores and lower extraversion levels predict better discourse comprehension performance. Lesion mapping results indicated that these convergent variables depend on a shared network of frontal and parietal regions, including white matter association tracts that bind these areas into a coordinated system. The observed findings motivate an integrative framework for understanding the neural foundations of discourse comprehension, suggesting that core elements of discourse processing emerge from a distributed network of brain regions that support specific competencies for executive and social function.

  6. Neural mechanisms of order information processing in working memory

    Directory of Open Access Journals (Sweden)

    Barbara Dolenc

    2013-11-01

    Full Text Available The ability to encode and maintain the exact order of short sequences of stimuli or events is often crucial to our ability for effective high-order planning. However, it is not yet clear which neural mechanisms underpin this process. Several studies suggest that in comparison with item recognition temporal order coding activates prefrontal and parietal brain regions. Results of various studies tend to favour the hypothesis that the order of the stimuli is represented and encoded on several stages, from primacy and recency estimates to the exact position of the item in a sequence. Different brain regions play a different role in this process. Dorsolateral prefrontal cortex has a more general role in attention, while the premotor cortex is more involved in the process of information grouping. Parietal lobe and hippocampus also play a significant role in order processing as they enable the representation of distance. Moreover, order maintenance is associated with the existence of neural oscillators that operate at different frequencies. Electrophysiological studies revealed that theta and alpha oscillations play an important role in the maintenance of temporal order information. Those EEG oscillations are differentially associated with processes that support the maintenance of order information and item recognition. Various studies suggest a link between prefrontal areas and memory for temporal order, implying that EEG neural oscillations in the prefrontal cortex may play a role in the maintenance of information on temporal order.

  7. Neural Control Mechanisms and Body Fluid Homeostasis

    Science.gov (United States)

    Johnson, Alan Kim

    1998-01-01

    The goal of the proposed research was to study the nature of afferent signals to the brain that reflect the status of body fluid balance and to investigate the central neural mechanisms that process this information for the activation of response systems which restore body fluid homeostasis. That is, in the face of loss of fluids from intracellular or extracellular fluid compartments, animals seek and ingest water and ionic solutions (particularly Na(+) solutions) to restore the intracellular and extracellular spaces. Over recent years, our laboratory has generated a substantial body of information indicating that: (1) a fall in systemic arterial pressure facilitates the ingestion of rehydrating solutions and (2) that the actions of brain amine systems (e.g., norepinephrine; serotonin) are critical for precise correction of fluid losses. Because both acute and chronic dehydration are associated with physiological stresses, such as exercise and sustained exposure to microgravity, the present research will aid in achieving a better understanding of how vital information is handled by the nervous system for maintenance of the body's fluid matrix which is critical for health and well-being.

  8. [Mechanism of neural plasticity of acupuncture on chronic migraine].

    Science.gov (United States)

    Xu, Xiaobai; Liu, Lu; Zhao, Luopeng; Qu, Zhengyang; Zhu, Yupu; Zhang, Yajie; Wang, Linpeng

    2017-10-12

    Chronic migraine is one of neurological disorders with high rate of disability, but sufficient attention has not been paid in this field. A large number of clinical studies have shown traditional Chinese acupuncture is a kind of effective treatment with less side effects. Through the analysis of literature regarding acupuncture and migraine published from 1981 to 2017 in CNKI and PubMed databases, the mechanism of neural plasticity of acupuncture on chronic migraine was explored. It was believed the progress of chronic migraine involved the changes of neural plasticity in neural structure and function, and the neural plasticity related with neural sensitization during the process of chronic migraine was discussed from three aspects of electrophysiology, molecular chemistry and radiography. Acupuncture could treat and prevent chronic migraine via the mechanism of neural plasticity, but there was no related literature, hindering the further spreading and development of acupuncture for chronic migraine.

  9. THE POTENTIAL NEURAL MECHANISMS OF ACUTE INDIRECT VIBRATION

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    Darryl J. Cochrane

    2011-03-01

    Full Text Available There is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception suggesting neural enhancement. Nevertheless, the neural mechanism(s of vibration and its potentiating effect have received little attention. One proposal suggests that spinal reflexes enhance muscle contraction through a reflex activity known as tonic vibration stretch reflex (TVR, which increases muscle activation. However, TVR is based on direct, brief, and high frequency vibration (>100 Hz which differs to indirect vibration, which is applied to the whole body or body parts at lower vibration frequency (5-45 Hz. Likewise, muscle tuning and neuromuscular aspects are other candidate mechanisms used to explain the vibration phenomenon. But there is much debate in terms of identifying which neural mechanism(s are responsible for acute vibration; due to a number of studies using various vibration testing protocols. These protocols include: different methods of application, vibration variables, training duration, exercise types and a range of population groups. Therefore, the neural mechanism of acute vibration remain equivocal, but spinal reflexes, muscle tuning and neuromuscular aspects are all viable factors that may contribute in different ways to increasing muscular performance. Additional research is encouraged to determine which neural mechanism(s and their contributions are responsible for acute vibration. Testing variables and vibration applications need to be standardised before reaching a consensus on which neural mechanism(s occur during and post-vibration

  10. Neural networks in support of manned space

    Science.gov (United States)

    Werbos, Paul J.

    1989-01-01

    Many lobbyists in Washington have argued that artificial intelligence (AI) is an alternative to manned space activity. In actuality, this is the opposite of the truth, especially as regards artificial neural networks (ANNs), that form of AI which has the greatest hope of mimicking human abilities in learning, ability to interface with sensors and actuators, flexibility and balanced judgement. ANNs and their relation to expert systems (the more traditional form of AI), and the limitations of both technologies are briefly reviewed. A Few highlights of recent work on ANNs, including an NSF-sponsored workshop on ANNs for control applications are given. Current thinking on ANNs for use in certain key areas (the National Aerospace Plane, teleoperation, the control of large structures, fault diagnostics, and docking) which may be crucial to the long term future of man in space is discussed.

  11. Neural Mechanisms Underlying Compensatory and Noncompensatory Strategies in Risky Choice

    NARCIS (Netherlands)

    van Duijvenvoorde, A.C.K.; Figner, B.; Weeda, W.D.; van der Molen, M.W.; Jansen, B.R.J.; Huizenga, H.M.

    Individuals may differ systematically in their applied decision strategies, which has critical implications for decision neuroscience but is yet scarcely studied. Our study's main focus was therefore to investigate the neural mechanisms underlying compensatory versus noncompensatory strategies in

  12. Neural mechanisms underlying compensatory and noncompensatory strategies in risky choice

    NARCIS (Netherlands)

    Duijvenvoorde, A.C.K. van; Figner, B.; Weeda, W.D.; Molen, M.W. van der; Jansen, B.R.J.; Huizenga, H.M.

    2016-01-01

    Individuals may differ systematically in their applied decision strategies, which has critical implications for decision neuroscience but is yet scarcely studied. Our study's main focus was therefore to investigate the neural mechanisms underlying compensatory versus noncompensatory strategies in

  13. Music listening after stroke: beneficial effects and potential neural mechanisms

    National Research Council Canada - National Science Library

    Särkämö, Teppo; Soto, David

    2012-01-01

    .... Then we will present findings about the short‐ and long‐term effects of music listening on the recovery of cognitive function in stroke patients and the underlying neural mechanisms of these music effects...

  14. On the neural mechanisms subserving consciousness and attention

    Directory of Open Access Journals (Sweden)

    Catherine eTallon-Baudry

    2012-01-01

    Full Text Available Consciousness, as described in the experimental literature, is a multi-faceted phenomenon, that impinges on other well-studied concepts such as attention and control. Do consciousness and attention refer to different aspects of the same core phenomenon, or do they correspond to distinct functions? One possibility to address this question is to examine the neural mechanisms underlying consciousness and attention. If consciousness and attention pertain to the same concept, they should rely on shared neural mechanisms. Conversely, if their underlying mechanisms are distinct, then consciousness and attention should be considered as distinct entities. This paper therefore reviews neurophysiological facts arguing in favor or against a tight relationship between consciousness and attention. Three neural mechanisms that have been associated with both attention and consciousness are examined (neural amplification, involvement of the fronto-parietal network, and oscillatory synchrony, to conclude that the commonalities between attention and consciousness at the neural level may have been overestimated. Last but not least, experiments in which both attention and consciousness were probed at the neural level point toward a dissociation between the two concepts. It therefore appears from this review that consciousness and attention rely on distinct neural properties, although they can interact at the behavioral level. It is proposed that a "cumulative influence model", in which attention and consciousness correspond to distinct neural mechanisms feeding a single decisional process leading to behavior, fits best with available neural and behavioral data. In this view, consciousness should not be considered as a top-level executive function but should rather be defined by its experiential properties.

  15. Culture and social support: neural bases and biological impact.

    Science.gov (United States)

    Sherman, David K; Kim, Heejung S; Taylor, Shelley E

    2009-01-01

    Social support is an effective means by which people cope with stressful events, and consequently, it beneficially affects health and well-being. Yet there are profound cultural differences in the effectiveness of different types of support and how people use their support networks. In this paper, we examine research on the impact of culture on social support, the neural underpinnings of social support, and how cultural differences in social support seeking are manifested biologically. We focus on cultural factors that may affect individuals' decisions to seek or not to seek social support and how culture moderates the impact of support seeking on biological and psychological health outcomes. We also examine recent research on the interaction between genes and culture in social support use. Discussion centers on the importance of developing an overarching framework of social support that integrates health psychology, cultural psychology, social neuroscience, and genetics.

  16. Does Artificial Neural Network Support Connectivism's Assumptions?

    Science.gov (United States)

    AlDahdouh, Alaa A.

    2017-01-01

    Connectivism was presented as a learning theory for the digital age and connectivists claim that recent developments in Artificial Intelligence (AI) and, more specifically, Artificial Neural Network (ANN) support their assumptions of knowledge connectivity. Yet, very little has been done to investigate this brave allegation. Does the advancement…

  17. Neural tube closure: cellular, molecular and biomechanical mechanisms.

    Science.gov (United States)

    Nikolopoulou, Evanthia; Galea, Gabriel L; Rolo, Ana; Greene, Nicholas D E; Copp, Andrew J

    2017-02-15

    Neural tube closure has been studied for many decades, across a range of vertebrates, as a paradigm of embryonic morphogenesis. Neurulation is of particular interest in view of the severe congenital malformations - 'neural tube defects' - that result when closure fails. The process of neural tube closure is complex and involves cellular events such as convergent extension, apical constriction and interkinetic nuclear migration, as well as precise molecular control via the non-canonical Wnt/planar cell polarity pathway, Shh/BMP signalling, and the transcription factors Grhl2/3, Pax3, Cdx2 and Zic2. More recently, biomechanical inputs into neural tube morphogenesis have also been identified. Here, we review these cellular, molecular and biomechanical mechanisms involved in neural tube closure, based on studies of various vertebrate species, focusing on the most recent advances in the field. © 2017. Published by The Company of Biologists Ltd.

  18. A canonical neural mechanism for behavioral variability

    Science.gov (United States)

    Darshan, Ran; Wood, William E.; Peters, Susan; Leblois, Arthur; Hansel, David

    2017-05-01

    The ability to generate variable movements is essential for learning and adjusting complex behaviours. This variability has been linked to the temporal irregularity of neuronal activity in the central nervous system. However, how neuronal irregularity actually translates into behavioural variability is unclear. Here we combine modelling, electrophysiological and behavioural studies to address this issue. We demonstrate that a model circuit comprising topographically organized and strongly recurrent neural networks can autonomously generate irregular motor behaviours. Simultaneous recordings of neurons in singing finches reveal that neural correlations increase across the circuit driving song variability, in agreement with the model predictions. Analysing behavioural data, we find remarkable similarities in the babbling statistics of 5-6-month-old human infants and juveniles from three songbird species and show that our model naturally accounts for these `universal' statistics.

  19. Developmental phonagnosia: Linking neural mechanisms with the behavioural phenotype.

    Science.gov (United States)

    Roswandowitz, Claudia; Schelinski, Stefanie; von Kriegstein, Katharina

    2017-07-15

    Human voice recognition is critical for many aspects of social communication. Recently, a rare disorder, developmental phonagnosia, which describes the inability to recognise a speaker's voice, has been discovered. The underlying neural mechanisms are unknown. Here, we used two functional magnetic resonance imaging experiments to investigate brain function in two behaviourally well characterised phonagnosia cases, both 32 years old: AS has apperceptive and SP associative phonagnosia. We found distinct malfunctioned brain mechanisms in AS and SP matching their behavioural profiles. In apperceptive phonagnosia, right-hemispheric auditory voice-sensitive regions (i.e., Heschl's gyrus, planum temporale, superior temporal gyrus) showed lower responses than in matched controls (nAS=16) for vocal versus non-vocal sounds and for speaker versus speech recognition. In associative phonagnosia, the connectivity between voice-sensitive (i.e. right posterior middle/inferior temporal gyrus) and supramodal (i.e. amygdala) regions was reduced in comparison to matched controls (nSP=16) during speaker versus speech recognition. Additionally, both cases recruited distinct potential compensatory mechanisms. Our results support a central assumption of current two-system models of voice-identity processing: They provide the first evidence that dysfunction of voice-sensitive regions and impaired connectivity between voice-sensitive and supramodal person recognition regions can selectively contribute to deficits in person recognition by voice. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Neural mechanisms of social influence in adolescence.

    Science.gov (United States)

    Welborn, B Locke; Lieberman, Matthew D; Goldenberg, Diane; Fuligni, Andrew J; Galván, Adriana; Telzer, Eva H

    2016-01-01

    During the transformative period of adolescence, social influence plays a prominent role in shaping young people's emerging social identities, and can impact their propensity to engage in prosocial or risky behaviors. In this study, we examine the neural correlates of social influence from both parents and peers, two important sources of influence. Nineteen adolescents (age 16-18 years) completed a social influence task during a functional magnetic resonance imaging (fMRI) scan. Social influence from both sources evoked activity in brain regions implicated in mentalizing (medial prefrontal cortex, left temporoparietal junction, right temporoparietal junction), reward (ventromedial prefrontal cortex), and self-control (right ventrolateral prefrontal cortex). These results suggest that mental state reasoning, social reward and self-control processes may help adolescents to evaluate others' perspectives and overcome the prepotent force of their own antecedent attitudes to shift their attitudes toward those of others. Findings suggest common neural networks involved in social influence from both parents and peers. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  1. Neural mechanisms underlying morphine withdrawal in addicted patients: a review

    Directory of Open Access Journals (Sweden)

    Nima Babhadiashar

    2015-06-01

    Full Text Available Morphine is one of the most potent alkaloid in opium, which has substantial medical uses and needs and it is the first active principle purified from herbal source. Morphine has commonly been used for relief of moderate to severe pain as it acts directly on the central nervous system; nonetheless, its chronic abuse increases tolerance and physical dependence, which is commonly known as opiate addiction. Morphine withdrawal syndrome is physiological and behavioral symptoms that stem from prolonged exposure to morphine. A majority of brain regions are hypofunctional over prolonged abstinence and acute morphine withdrawal. Furthermore, several neural mechanisms are likely to contribute to morphine withdrawal. The present review summarizes the literature pertaining to neural mechanisms underlying morphine withdrawal. Despite the fact that morphine withdrawal is a complex process, it is suggested that neural mechanisms play key roles in morphine withdrawal.

  2. Neural mechanism of facilitation system during physical fatigue.

    Directory of Open Access Journals (Sweden)

    Masaaki Tanaka

    Full Text Available An enhanced facilitation system caused by motivational input plays an important role in supporting performance during physical fatigue. We tried to clarify the neural mechanisms of the facilitation system during physical fatigue using magnetoencephalography (MEG and a classical conditioning technique. Twelve right-handed volunteers participated in this study. Participants underwent MEG recording during the imagery of maximum grips of the right hand guided by metronome sounds for 10 min. Thereafter, fatigue-inducing maximum handgrip trials were performed for 10 min; the metronome sounds were started 5 min after the beginning of the handgrip trials. The metronome sounds were used as conditioned stimuli and maximum handgrip trials as unconditioned stimuli. The next day, they were randomly assigned to two groups in a single-blinded, two-crossover fashion to undergo two types of MEG recordings, that is, for the control and motivation sessions, during the imagery of maximum grips of the right hand guided by metronome sounds for 10 min. The alpha-band event-related desynchronizations (ERDs of the motivation session relative to the control session within the time windows of 500 to 700 and 800 to 900 ms after the onset of handgrip cue sounds were identified in the sensorimotor areas. In addition, the alpha-band ERD within the time window of 400 to 500 ms was identified in the right dorsolateral prefrontal cortex (Brodmann's area 46. The ERD level in the right dorsolateral prefrontal cortex was positively associated with that in the sensorimotor areas within the time window of 500 to 700 ms. These results suggest that the right dorsolateral prefrontal cortex is involved in the neural substrates of the facilitation system and activates the sensorimotor areas during physical fatigue.

  3. Neural cell image segmentation method based on support vector machine

    Science.gov (United States)

    Niu, Shiwei; Ren, Kan

    2015-10-01

    In the analysis of neural cell images gained by optical microscope, accurate and rapid segmentation is the foundation of nerve cell detection system. In this paper, a modified image segmentation method based on Support Vector Machine (SVM) is proposed to reduce the adverse impact caused by low contrast ratio between objects and background, adherent and clustered cells' interference etc. Firstly, Morphological Filtering and OTSU Method are applied to preprocess images for extracting the neural cells roughly. Secondly, the Stellate Vector, Circularity and Histogram of Oriented Gradient (HOG) features are computed to train SVM model. Finally, the incremental learning SVM classifier is used to classify the preprocessed images, and the initial recognition areas identified by the SVM classifier are added to the library as the positive samples for training SVM model. Experiment results show that the proposed algorithm can achieve much better segmented results than the classic segmentation algorithms.

  4. Distinct neural mechanisms for body form and body motion discriminations

    NARCIS (Netherlands)

    Vangeneugden, Joris; Peelen, Marius V; Tadin, Duje; Battelli, Lorella

    2014-01-01

    Actions can be understood based on form cues (e.g., static body posture) as well as motion cues (e.g., gait patterns). A fundamental debate centers on the question of whether the functional and neural mechanisms processing these two types of cues are dissociable. Here, using fMRI, psychophysics, and

  5. Distinct Neural Mechanisms Mediate Olfactory Memory Formation at Different Timescales

    Science.gov (United States)

    McNamara, Ann Marie; Magidson, Phillip D.; Linster, Christiane; Wilson, Donald A.; Cleland, Thomas A.

    2008-01-01

    Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is…

  6. Neural Circuitry and Plasticity Mechanisms Underlying Delay Eyeblink Conditioning

    Science.gov (United States)

    Freeman, John H.; Steinmetz, Adam B.

    2011-01-01

    Pavlovian eyeblink conditioning has been used extensively as a model system for examining the neural mechanisms underlying associative learning. Delay eyeblink conditioning depends on the intermediate cerebellum ipsilateral to the conditioned eye. Evidence favors a two-site plasticity model within the cerebellum with long-term depression of…

  7. Neural and cognitive mechanisms of creativity

    NARCIS (Netherlands)

    Akbari Chermahini, Soghra

    2011-01-01

    The studies of this thesis provide empirical evidence that creativity is not a homogeneous concept; rather it reflects the interplay of separate, dissociable processes such as convergent and divergent thinking (e.g., Guilford, 1967). The cognitive mechanism of these two processes is different, but

  8. Evolutionary vaccination dynamics with internal support mechanisms

    Science.gov (United States)

    Tang, Guo-Mei; Cai, Chao-Ran; Wu, Zhi-Xi

    2017-05-01

    This paper reports internal support mechanisms (i.e., without external intervention) to enhance the vaccine coverage in the evolutionary vaccination dynamics. We present two internal support mechanisms, one is global support mechanism in which each individual pays a support cost to build up a public fund and then the public fund is divided by all vaccinated individuals, while another is local support mechanism in which each individual pays a support cost and then this support cost will be divided by its immediate vaccinated neighbors. By means of extensive computer simulations, we show that, in the same strength of support cost, the heterogeneous (local) support mechanism can encourage more people to take vaccination than the homogeneous (global) support mechanism. And then, we study the most general case that includes supporters and troublemakers together, where supporters (troublemakers) mean that the individuals join (do not join) the internal support mechanism, in the population. We surprisingly find that, in scale-free networks, the voluntary vaccination dynamics with the local support mechanism will not degrade into the original voluntary vaccination dynamics, and the vaccination level can still be effectively improved. In view of most social networks are of scale-free degree distribution, we study further in empirical networks and find that the vaccination level can still be improved in the absence of external intervention.

  9. Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks

    Energy Technology Data Exchange (ETDEWEB)

    Ziaul Huque

    2007-08-31

    This is the final technical report for the project titled 'Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks'. The aim of the project was to develop an efficient chemistry model for combustion simulations. The reduced chemistry model was developed mathematically without the need of having extensive knowledge of the chemistry involved. To aid in the development of the model, Neural Networks (NN) was used via a new network topology known as Non-linear Principal Components Analysis (NPCA). A commonly used Multilayer Perceptron Neural Network (MLP-NN) was modified to implement NPCA-NN. The training rate of NPCA-NN was improved with the GEneralized Regression Neural Network (GRNN) based on kernel smoothing techniques. Kernel smoothing provides a simple way of finding structure in data set without the imposition of a parametric model. The trajectory data of the reaction mechanism was generated based on the optimization techniques of genetic algorithm (GA). The NPCA-NN algorithm was then used for the reduction of Dimethyl Ether (DME) mechanism. DME is a recently discovered fuel made from natural gas, (and other feedstock such as coal, biomass, and urban wastes) which can be used in compression ignition engines as a substitute for diesel. An in-house two-dimensional Computational Fluid Dynamics (CFD) code was developed based on Meshfree technique and time marching solution algorithm. The project also provided valuable research experience to two graduate students.

  10. Development of neural mechanisms for machine learning.

    Science.gov (United States)

    Arsenio, Artur M

    2005-01-01

    The goal of this work is to develop a humanoid robot's perceptual mechanisms through the use of learning aids. We describe methods to enable learning on a humanoid robot using learning aids such as books, drawing materials, boards, educational videos or other children toys. Visual properties of objects are learned and inserted into a recognition scheme, which is then applied to acquire new object representations - we propose learning through developmental stages. Inspired in infant development, we will also boost the robot's perceptual capabilities by having a human caregiver performing educational and play activities with the robot (such as drawing, painting or playing with a toy train on a railway). We describe original algorithms to extract meaningful percepts from such learning experiments. Experimental evaluation of the algorithms corroborates the theoretical framework.

  11. Potential Mechanisms and Functions of Intermittent Neural Synchronization

    Directory of Open Access Journals (Sweden)

    Sungwoo Ahn

    2017-05-01

    Full Text Available Neural synchronization is believed to play an important role in different brain functions. Synchrony in cortical and subcortical circuits is frequently variable in time and not perfect. Few long intervals of desynchronized dynamics may be functionally different from many short desynchronized intervals although the average synchrony may be the same. Recent analysis of imperfect synchrony in different neural systems reported one common feature: neural oscillations may go out of synchrony frequently, but primarily for a short time interval. This study explores potential mechanisms and functional advantages of this short desynchronizations dynamics using computational neuroscience techniques. We show that short desynchronizations are exhibited in coupled neurons if their delayed rectifier potassium current has relatively large values of the voltage-dependent activation time-constant. The delayed activation of potassium current is associated with generation of quickly-rising action potential. This “spikiness” is a very general property of neurons. This may explain why very different neural systems exhibit short desynchronization dynamics. We also show how the distribution of desynchronization durations may be independent of the synchronization strength. Finally, we show that short desynchronization dynamics requires weaker synaptic input to reach a pre-set synchrony level. Thus, this dynamics allows for efficient regulation of synchrony and may promote efficient formation of synchronous neural assemblies.

  12. Language and cognition interaction neural mechanisms.

    Science.gov (United States)

    Perlovsky, Leonid

    2011-01-01

    How language and cognition interact in thinking? Is language just used for communication of completed thoughts, or is it fundamental for thinking? Existing approaches have not led to a computational theory. We develop a hypothesis that language and cognition are two separate but closely interacting mechanisms. Language accumulates cultural wisdom; cognition develops mental representations modeling surrounding world and adapts cultural knowledge to concrete circumstances of life. Language is acquired from surrounding language "ready-made" and therefore can be acquired early in life. This early acquisition of language in childhood encompasses the entire hierarchy from sounds to words, to phrases, and to highest concepts existing in culture. Cognition is developed from experience. Yet cognition cannot be acquired from experience alone; language is a necessary intermediary, a "teacher." A mathematical model is developed; it overcomes previous difficulties and leads to a computational theory. This model is consistent with Arbib's "language prewired brain" built on top of mirror neuron system. It models recent neuroimaging data about cognition, remaining unnoticed by other theories. A number of properties of language and cognition are explained, which previously seemed mysterious, including influence of language grammar on cultural evolution, which may explain specifics of English and Arabic cultures.

  13. Language and Cognition Interaction Neural Mechanisms

    Directory of Open Access Journals (Sweden)

    Leonid Perlovsky

    2011-01-01

    Full Text Available How language and cognition interact in thinking? Is language just used for communication of completed thoughts, or is it fundamental for thinking? Existing approaches have not led to a computational theory. We develop a hypothesis that language and cognition are two separate but closely interacting mechanisms. Language accumulates cultural wisdom; cognition develops mental representations modeling surrounding world and adapts cultural knowledge to concrete circumstances of life. Language is acquired from surrounding language “ready-made” and therefore can be acquired early in life. This early acquisition of language in childhood encompasses the entire hierarchy from sounds to words, to phrases, and to highest concepts existing in culture. Cognition is developed from experience. Yet cognition cannot be acquired from experience alone; language is a necessary intermediary, a “teacher.” A mathematical model is developed; it overcomes previous difficulties and leads to a computational theory. This model is consistent with Arbib's “language prewired brain” built on top of mirror neuron system. It models recent neuroimaging data about cognition, remaining unnoticed by other theories. A number of properties of language and cognition are explained, which previously seemed mysterious, including influence of language grammar on cultural evolution, which may explain specifics of English and Arabic cultures.

  14. Multiple neural mechanisms for coloring words in synesthesia.

    Science.gov (United States)

    Yokoyama, Takemasa; Noguchi, Yasuki; Koga, Hiroki; Tachibana, Ryosuke; Saiki, Jun; Kakigi, Ryusuke; Kita, Shinichi

    2014-07-01

    Grapheme-color synesthesia is a phenomenon in which achromatic letters/digits automatically induce particular colors. When multiple letters are integrated into a word, some synesthetes perceive that all those letters are changed into the same color, reporting lexical color to that word. Previous psychological studies found several "rules" that determine those lexical colors. The colors to most words are determined by the first letters of the words, while some words in ordinal sequences have their specific colors. Recent studies further reported the third case where lexical colors might be influenced by semantic information of words. Although neural mechanisms determining those lexical colors remained unknown, here we identified three separate neural systems in the synesthete's brain underlying three rules for illusory coloring of words. In addition to the occipito-temporal and parietal regions previously found to be associated with the grapheme-color synesthesia, neural systems for lexical coloring extended to linguistic areas in the left inferior frontal and anterior temporal regions that were engaged in semantic analyses of words. Those results indicate an involvement of wider and higher neural networks than previously assumed in a production of synesthetic colors to visual stimuli and further showed a multiplicity of synesthetic mechanisms represented in the single brain. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Neural systems supporting and affecting economically relevant behavior

    Directory of Open Access Journals (Sweden)

    Braeutigam S

    2012-05-01

    Full Text Available Sven BraeutigamOxford Centre for Human Brain Activity, University of Oxford, Oxford, United KingdomAbstract: For about a hundred years, theorists and traders alike have tried to unravel and understand the mechanisms and hidden rules underlying and perhaps determining economically relevant behavior. This review focuses on recent developments in neuroeconomics, where the emphasis is placed on two directions of research: first, research exploiting common experiences of urban inhabitants in industrialized societies to provide experimental paradigms with a broader real-life content; second, research based on behavioral genetics, which provides an additional dimension for experimental control and manipulation. In addition, possible limitations of state-of-the-art neuroeconomics research are addressed. It is argued that observations of neuronal systems involved in economic behavior converge to some extent across the technologies and paradigms used. Conceptually, the data available as of today raise the possibility that neuroeconomic research might provide evidence at the neuronal level for the existence of multiple systems of thought and for the importance of conflict. Methodologically, Bayesian approaches in particular may play an important role in identifying mechanisms and establishing causality between patterns of neural activity and economic behavior.Keywords: neuroeconomics, behavioral genetics, decision-making, consumer behavior, neural system

  16. Music listening after stroke: beneficial effects and potential neural mechanisms.

    Science.gov (United States)

    Särkämö, Teppo; Soto, David

    2012-04-01

    Music is an enjoyable leisure activity that also engages many emotional, cognitive, and motor processes in the brain. Here, we will first review previous literature on the emotional and cognitive effects of music listening in healthy persons and various clinical groups. Then we will present findings about the short- and long-term effects of music listening on the recovery of cognitive function in stroke patients and the underlying neural mechanisms of these music effects. First, our results indicate that listening to pleasant music can have a short-term facilitating effect on visual awareness in patients with visual neglect, which is associated with functional coupling between emotional and attentional brain regions. Second, daily music listening can improve auditory and verbal memory, focused attention, and mood as well as induce structural gray matter changes in the early poststroke stage. The psychological and neural mechanisms potentially underlying the rehabilitating effect of music after stroke are discussed. © 2012 New York Academy of Sciences.

  17. Neural mechanisms of contextual influences during social perceptual decisions

    OpenAIRE

    El Zein, Marwa

    2015-01-01

    Everyday social decisions require the combination of multiple sources of information and therefore build upon abundant contextual elements such as the social cues of emitters (e.g., gaze direction, emotion, gesture), the attentional focus of observers, their mood and their past experience. The work conducted during this Ph.D. (including three main studies in healthy human subjects) aimed at characterizing the cognitive and neural mechanisms of contextual influences in social settings. The fir...

  18. Neurobiological mechanisms supporting experience-dependent resistance to social stress.

    Science.gov (United States)

    Cooper, M A; Clinard, C T; Morrison, K E

    2015-04-16

    Humans and other animals show a remarkable capacity for resilience following traumatic, stressful events. Resilience is thought to be an active process related to coping with stress, although the cellular and molecular mechanisms that support active coping and stress resistance remain poorly understood. In this review, we focus on the neurobiological mechanisms by which environmental and social experiences promote stress resistance. In male Syrian hamsters, exposure to a brief social defeat stressor leads to increased avoidance of novel opponents, which we call conditioned defeat. Also, hamsters that have achieved dominant social status show reduced conditioned defeat as well as cellular and molecular changes in the neural circuits controlling the conditioned defeat response. We propose that experience-dependent neural plasticity occurs in the prelimbic (PL) cortex, infralimbic (IL) cortex, and ventral medial amygdala (vMeA) during the maintenance of dominance relationships, and that adaptations in these neural circuits support stress resistance in dominant individuals. Overall, behavioral treatments that promote success in competitive interactions may represent valuable interventions for instilling resilience. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Fossil fuel support mechanisms in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Lampinen, Ari

    2013-10-15

    Fossil fuel subsidies and other state support for fossil fuels are forbidden by the Kyoto Protocol and other international treaties. However, they are still commonly used. This publication presents and analyses diverse state support mechanisms for fossil fuels in Finland in 2003-2010. Total of 38 support mechanisms are covered in quantitative analysis and some other mechanisms are mentioned qualitatively only. For some mechanisms the study includes a longer historical perspective. This is the case for tax subsidies for crude oil based traffic fuels that have been maintained in Finland since 1965.

  20. Astrocytes: Tailored to Support the Demand of Neural Circuits?

    DEFF Research Database (Denmark)

    Rasmussen, Rune

    2017-01-01

    Anatomy, physiology, proteomics, and genomics reveal the prospect of distinct highly specialized astrocyte subtypes within neural circuits.......Anatomy, physiology, proteomics, and genomics reveal the prospect of distinct highly specialized astrocyte subtypes within neural circuits....

  1. Neural Mechanisms and Information Processing in Recognition Systems

    Directory of Open Access Journals (Sweden)

    Mamiko Ozaki

    2014-10-01

    Full Text Available Nestmate recognition is a hallmark of social insects. It is based on the match/mismatch of an identity signal carried by members of the society with that of the perceiving individual. While the behavioral response, amicable or aggressive, is very clear, the neural systems underlying recognition are not fully understood. Here we contrast two alternative hypotheses for the neural mechanisms that are responsible for the perception and information processing in recognition. We focus on recognition via chemical signals, as the common modality in social insects. The first, classical, hypothesis states that upon perception of recognition cues by the sensory system the information is passed as is to the antennal lobes and to higher brain centers where the information is deciphered and compared to a neural template. Match or mismatch information is then transferred to some behavior-generating centers where the appropriate response is elicited. An alternative hypothesis, that of “pre-filter mechanism”, posits that the decision as to whether to pass on the information to the central nervous system takes place in the peripheral sensory system. We suggest that, through sensory adaptation, only alien signals are passed on to the brain, specifically to an “aggressive-behavior-switching center”, where the response is generated if the signal is above a certain threshold.

  2. Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks

    Energy Technology Data Exchange (ETDEWEB)

    Nelson Butuk

    2005-12-01

    This is an annual technical report for the work done over the last year (period ending 9/30/2005) on the project titled ''Mathematically Reduced Chemical Reaction Mechanism Using Neural Networks''. The aim of the project is to develop an efficient chemistry model for combustion simulations. The reduced chemistry model will be developed mathematically without the need of having extensive knowledge of the chemistry involved. To aid in the development of the model, Neural Networks (NN) will be used via a new network topology know as Non-linear Principal Components Analysis (NPCA). We report on the development of a novel procedure to speed up the training of NPCA. The same procedure termed L{sub 2}Boost can be used to increase the order of approximation of the Generalized Regression Neural Network (GRNN). It is pointed out that GRNN is a basic procedure for the emerging mesh free CFD. Also reported is an efficient simple approach of computing the derivatives of GRNN function approximation using complex variables or the Complex Step Method (CSM). The results presented demonstrate the significance of the methods developed and will be useful in many areas of applied science and engineering.

  3. Neural mechanisms of decision making in hoarding disorder.

    Science.gov (United States)

    Tolin, David F; Stevens, Michael C; Villavicencio, Anna L; Norberg, Melissa M; Calhoun, Vince D; Frost, Randy O; Steketee, Gail; Rauch, Scott L; Pearlson, Godfrey D

    2012-08-01

    Hoarding disorder (HD), previously considered a subtype of obsessive-compulsive disorder (OCD), has been proposed as a unique diagnostic entity in DSM-5. Current models of HD emphasize problems of decision-making, attachment to possessions, and poor insight, whereas previous neuroimaging studies have suggested abnormalities in frontal brain regions. To examine the neural mechanisms of impaired decision making in HD in patients with well-defined primary HD compared with patients with OCD and healthy control subjects (HCs). We compared neural activity among patients with HD, patients with OCD, and HCs during decisions to keep or discard personal possessions and control possessions from November 9, 2006, to August 13, 2010. Private, not-for-profit hospital. A total of 107 adults (43 with HD, 31 with OCD, and 33 HCs). Neural activity as measured by functional magnetic resonance imaging in which actual real-time and binding decisions had to be made about whether to keep or discard possessions. Compared with participants with OCD and HC, participants with HD exhibited abnormal activity in the anterior cingulate cortex and insula that was stimulus dependent. Specifically, when deciding about items that did not belong to them, patients with HD showed relatively lower activity in these brain regions. However, when deciding about items that belonged to them, these regions showed excessive functional magnetic resonance imaging signals compared with the other 2 groups. These differences in neural function correlated significantly with hoarding severity and self-ratings of indecisiveness and "not just right" feelings among patients with HD and were unattributable to OCD or depressive symptoms. Findings suggest a biphasic abnormality in anterior cingulate cortex and insula function in patients with HD related to problems in identifying the emotional significance of a stimulus, generating appropriate emotional response, or regulating affective state during decision making.

  4. A simple mechanical system for studying adaptive oscillatory neural networks

    DEFF Research Database (Denmark)

    Jouffroy, Guillaume; Jouffroy, Jerome

    model, etc.) might be too complex to study. In this paper, we use a comparatively simple mechanical system, the nonholonomic vehicle referred to as the Roller-Racer, as a means towards testing different learning strategies for an Recurrent Neural Network-based (RNN) controller/guidance system. After...... a brief description of the Roller-Racer, we present as a preliminary study an RNN-based feed-forward controller whose parameters are obtained through the well-known teacher forcing learning algorithm, extended to learn signals with a continuous component....

  5. Computer simulations of neural mechanisms explaining upper and lower limb excitatory neural coupling

    Directory of Open Access Journals (Sweden)

    Ferris Daniel P

    2010-12-01

    Full Text Available Abstract Background When humans perform rhythmic upper and lower limb locomotor-like movements, there is an excitatory effect of upper limb exertion on lower limb muscle recruitment. To investigate potential neural mechanisms for this behavioral observation, we developed computer simulations modeling interlimb neural pathways among central pattern generators. We hypothesized that enhancement of muscle recruitment from interlimb spinal mechanisms was not sufficient to explain muscle enhancement levels observed in experimental data. Methods We used Matsuoka oscillators for the central pattern generators (CPG and determined parameters that enhanced amplitudes of rhythmic steady state bursts. Potential mechanisms for output enhancement were excitatory and inhibitory sensory feedback gains, excitatory and inhibitory interlimb coupling gains, and coupling geometry. We first simulated the simplest case, a single CPG, and then expanded the model to have two CPGs and lastly four CPGs. In the two and four CPG models, the lower limb CPGs did not receive supraspinal input such that the only mechanisms available for enhancing output were interlimb coupling gains and sensory feedback gains. Results In a two-CPG model with inhibitory sensory feedback gains, only excitatory gains of ipsilateral flexor-extensor/extensor-flexor coupling produced reciprocal upper-lower limb bursts and enhanced output up to 26%. In a two-CPG model with excitatory sensory feedback gains, excitatory gains of contralateral flexor-flexor/extensor-extensor coupling produced reciprocal upper-lower limb bursts and enhanced output up to 100%. However, within a given excitatory sensory feedback gain, enhancement due to excitatory interlimb gains could only reach levels up to 20%. Interconnecting four CPGs to have ipsilateral flexor-extensor/extensor-flexor coupling, contralateral flexor-flexor/extensor-extensor coupling, and bilateral flexor-extensor/extensor-flexor coupling could enhance

  6. Dissociable neural mechanisms underlying the modulation of pain and anxiety? An FMRI pilot study.

    Directory of Open Access Journals (Sweden)

    Katja Wiech

    Full Text Available The down-regulation of pain through beliefs is commonly discussed as a form of emotion regulation. In line with this interpretation, the analgesic effect has been shown to co-occur with reduced anxiety and increased activity in the ventrolateral prefrontal cortex (VLPFC, which is a key region of emotion regulation. This link between pain and anxiety modulation raises the question whether the two effects are rooted in the same neural mechanism. In this pilot fMRI study, we compared the neural basis of the analgesic and anxiolytic effect of two types of threat modulation: a "behavioral control" paradigm, which involves the ability to terminate a noxious stimulus, and a "safety signaling" paradigm, which involves visual cues that signal the threat (or absence of threat that a subsequent noxious stimulus might be of unusually high intensity. Analgesia was paralleled by VLPFC activity during behavioral control. Safety signaling engaged elements of the descending pain control system, including the rostral anterior cingulate cortex that showed increased functional connectivity with the periaqueductal gray and VLPFC. Anxiety reduction, in contrast, scaled with dorsolateral prefrontal cortex activation during behavioral control but had no distinct neural signature during safety signaling. Our pilot data therefore suggest that analgesic and anxiolytic effects are instantiated in distinguishable neural mechanisms and differ between distinct stress- and pain-modulatory approaches, supporting the recent notion of multiple pathways subserving top-down modulation of the pain experience. Additional studies in larger cohorts are needed to follow up on these preliminary findings.

  7. A staff support mechanism: the transformational partnership.

    Science.gov (United States)

    Cushen, N; Wigens, L

    There have been many changes in nursing over the past decade, e.g. the movement of nursing education into higher educational sectors and the generation of many new nursing roles. The development of senior roles within nursing could potentially lead to isolation and, consequently, there may be calls for complementary support mechanisms. A transformational partnership is advocated, whereby nurses working in different organizations/specialties can provide mutual support. Existing support mechanisms for senior nursing can be variable and a transformational partnership can complement these as well as providing mutual clinical support. There are many advantages to this form of partnership which include professional and personal development as well as time out to reflect on practice. It requires commitment to the validity of the concept of professional support across traditional boundaries. A framework based on Holt's (1994) change theory is suggested as a method of implementing this initiative more widely within neighbouring organizations.

  8. Psychological and neural mechanisms of experimental extinction: a selective review.

    Science.gov (United States)

    Delamater, Andrew R; Westbrook, R Frederick

    2014-02-01

    The present review examines key psychological concepts in the study of experimental extinction and implications these have for an understanding of the underlying neurobiology of extinction learning. We suggest that many of the signature characteristics of extinction learning (spontaneous recovery, renewal, reinstatement, rapid reacquisition) can be accommodated by the standard associative learning theory assumption that extinction results in partial erasure of the original learning together with new inhibitory learning. Moreover, we consider recent behavioral and neural evidence that supports the partial erasure view of extinction, but also note shortcomings in our understanding of extinction circuits as these relate to the negative prediction error concept. Recent work suggests that common prediction error and stimulus-specific prediction error terms both may be required to explain neural plasticity both in acquisition and extinction learning. In addition, we suggest that many issues in the content of extinction learning have not been fully addressed in current research, but that neurobiological approaches should be especially helpful in addressing such issues. These include questions about the nature of extinction learning (excitatory CS-No US, inhibitory CS-US learning, occasion setting processes), especially as this relates to studies of the micro-circuitry of extinction, as well as its representational content (sensory, motivational, response). An additional understudied problem in extinction research is the role played by attention processes and their underlying neural networks, although some research and theory converge on the idea that extinction is accompanied by attention decrements (i.e., habituation-like processes). Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Neural mechanisms of smooth pursuit eye movements in schizotypy.

    Science.gov (United States)

    Meyhöfer, Inga; Steffens, Maria; Kasparbauer, Anna; Grant, Phillip; Weber, Bernd; Ettinger, Ulrich

    2015-01-01

    Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty-one healthy participants [N = 19 low schizotypes, N = 12 high schizotypes (HS)] underwent functional magnetic resonance imaging at 3T with concurrent oculographic recording while performing a SPEM task with sinusoidal stimuli at two velocities (0.2 and 0.4 Hz). Behaviorally, a significant interaction between schizotypy group and velocity was found for frequency of saccades during SPEM, indicating impairments in HS in the slow but not the fast condition. On the neural level, HS demonstrated lower brain activation in different regions of the occipital lobe known to be associated with early sensory and attentional processing and motion perception (V3A, middle occipital gyrus, and fusiform gyrus). This group difference in neural activation was independent of target velocity. Together, these findings replicate the observation of altered pursuit performance in highly schizotypal individuals and, for the first time, identify brain activation patterns accompanying these performance changes. These posterior activation differences are compatible with evidence of motion processing deficits from the schizophrenia literature and, therefore, suggest overlap between schizotypy and schizophrenia both on cognitive-perceptual and neurophysiological levels. However, deficits in frontal motor areas observed during pursuit in schizophrenia were not seen here, suggesting the operation of additional genetic and/or illness-related influences in the clinical disorder. © 2014 Wiley Periodicals, Inc.

  10. MECHANISMS OF RIGHT VENTRICULAR FAILURE AND BIVENTRICULAR MECHANICAL CIRCULATORY SUPPORT

    Directory of Open Access Journals (Sweden)

    G. P. Itkin

    2013-01-01

    Full Text Available The paper presents a review of the problems of mechanical circulatory support with left ventricular bypass in total cardiac failure. Dysfunction of right ventricular defines the high mortality on left ventricular device. One of the effective methods for solving this problem is the use of right ventricular assisted devices. There are considered of the basic physiological mechanisms of interaction between the right and left ventricles of the heart, affecting on the function of the right heart. Shows the need to assess right ventricular function before deciding on mechanical circulatory support. Provides examples of the estimation the predictors of the right ventricular failure. The basic methods and devices of biventricular circulatory support were con- sidered. 

  11. Neural mechanisms underlying social conformity in an ultimatum game

    Directory of Open Access Journals (Sweden)

    Zhenyu eWei

    2013-12-01

    Full Text Available When individuals’ actions are incongruent with those of the group they belong to, they may change their initial behavior in order to conform to the group norm. This phenomenon is known as social conformity. In the present study, we used event-related functional magnetic resonance imaging (fMRI to investigate brain activity in response to group opinion during an ultimatum game. Results showed that participants changed their choices when these choices conflicted with the normative opinion of the group they were members of, especially in conditions of unfair treatment. The fMRI data revealed that a conflict with group norms activated the brain regions involved in norm violations and behavioral adjustment. Furthermore, in the reject-unfair condition, we observed that a conflict with group norms activated the medial frontal gyrus. These findings contribute to recent research examining neural mechanisms involved in detecting violations of social norms, and provide information regarding the neural representation of conformity behavior in an economic game.

  12. Neural mechanisms of rhythm perception: current findings and future perspectives.

    Science.gov (United States)

    Grahn, Jessica A

    2012-10-01

    Perception of temporal patterns is fundamental to normal hearing, speech, motor control, and music. Certain types of pattern understanding are unique to humans, such as musical rhythm. Although human responses to musical rhythm are universal, there is much we do not understand about how rhythm is processed in the brain. Here, I consider findings from research into basic timing mechanisms and models through to the neuroscience of rhythm and meter. A network of neural areas, including motor regions, is regularly implicated in basic timing as well as processing of musical rhythm. However, fractionating the specific roles of individual areas in this network has remained a challenge. Distinctions in activity patterns appear between "automatic" and "cognitively controlled" timing processes, but the perception of musical rhythm requires features of both automatic and controlled processes. In addition, many experimental manipulations rely on participants directing their attention toward or away from certain stimulus features, and measuring corresponding differences in neural activity. Many temporal features, however, are implicitly processed whether attended to or not, making it difficult to create controlled baseline conditions for experimental comparisons. The variety of stimuli, paradigms, and definitions can further complicate comparisons across domains or methodologies. Despite these challenges, the high level of interest and multitude of methodological approaches from different cognitive domains (including music, language, and motor learning) have yielded new insights and hold promise for future progress. Copyright © 2012 Cognitive Science Society, Inc.

  13. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

    Science.gov (United States)

    Chevalier, N. R.; Gazguez, E.; Bidault, L.; Guilbert, T.; Vias, C.; Vian, E.; Watanabe, Y.; Muller, L.; Germain, S.; Bondurand, N.; Dufour, S.; Fleury, V.

    2016-02-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

  14. Neural mechanisms underlying social conformity in an ultimatum game.

    Science.gov (United States)

    Wei, Zhenyu; Zhao, Zhiying; Zheng, Yong

    2013-01-01

    When individuals' actions are incongruent with those of the group they belong to, they may change their initial behavior in order to conform to the group norm. This phenomenon is known as "social conformity." In the present study, we used event-related functional magnetic resonance imaging (fMRI) to investigate brain activity in response to group opinion during an ultimatum game. Results showed that participants changed their choices when these choices conflicted with the normative opinion of the group they were members of, especially in conditions of unfair treatment. The fMRI data revealed that a conflict with group norms activated the brain regions involved in norm violations and behavioral adjustment. Furthermore, in the reject-unfair condition, we observed that a conflict with group norms activated the medial frontal gyrus. These findings contribute to recent research examining neural mechanisms involved in detecting violations of social norms, and provide information regarding the neural representation of conformity behavior in an economic game.

  15. Radial basis function (RBF) neural network control for mechanical systems design, analysis and Matlab simulation

    CERN Document Server

    Liu, Jinkun

    2013-01-01

    Radial Basis Function (RBF) Neural Network Control for Mechanical Systems is motivated by the need for systematic design approaches to stable adaptive control system design using neural network approximation-based techniques. The main objectives of the book are to introduce the concrete design methods and MATLAB simulation of stable adaptive RBF neural control strategies. In this book, a broad range of implementable neural network control design methods for mechanical systems are presented, such as robot manipulators, inverted pendulums, single link flexible joint robots, motors, etc. Advanced neural network controller design methods and their stability analysis are explored. The book provides readers with the fundamentals of neural network control system design.   This book is intended for the researchers in the fields of neural adaptive control, mechanical systems, Matlab simulation, engineering design, robotics and automation. Jinkun Liu is a professor at Beijing University of Aeronautics and Astronauti...

  16. Federal Mechanisms to Support Intervention Dissemination

    Science.gov (United States)

    Diana, Augusto; Bennett, Nicole

    2015-01-01

    This paper examines federal mechanisms that support program developers and researchers in disseminating effective interventions for public benefit. The purpose of this paper is not to discuss the dissemination of intervention research (i.e., how to inform stakeholders about research findings), nor is it intended to discuss the research of…

  17. Remodeling myelination: implications for mechanisms of neural plasticity.

    Science.gov (United States)

    Chang, Kae-Jiun; Redmond, Stephanie A; Chan, Jonah R

    2016-02-01

    One of the most significant paradigm shifts in membrane remodeling is the emerging view that membrane transformation is not exclusively controlled by cytoskeletal rearrangement, but also by biophysical constraints, adhesive forces, membrane curvature and compaction. One of the most exquisite examples of membrane remodeling is myelination. The advent of myelin was instrumental in advancing the nervous system during vertebrate evolution. With more rapid and efficient communication between neurons, faster and more complex computations could be performed in a given time and space. Our knowledge of how myelin-forming oligodendrocytes select and wrap axons has been limited by insufficient spatial and temporal resolution. By virtue of recent technological advances, progress has clarified longstanding controversies in the field. Here we review insights into myelination, from target selection to axon wrapping and membrane compaction, and discuss how understanding these processes has unexpectedly opened new avenues of insight into myelination-centered mechanisms of neural plasticity.

  18. Neural circuit mechanisms of short-term memory

    Science.gov (United States)

    Goldman, Mark

    Memory over time scales of seconds to tens of seconds is thought to be maintained by neural activity that is triggered by a memorized stimulus and persists long after the stimulus is turned off. This presents a challenge to current models of memory-storing mechanisms, because the typical time scales associated with cellular and synaptic dynamics are two orders of magnitude smaller than this. While such long time scales can easily be achieved by bistable processes that toggle like a flip-flop between a baseline and elevated-activity state, many neuronal systems have been observed experimentally to be capable of maintaining a continuum of stable states. For example, in neural integrator networks involved in the accumulation of evidence for decision making and in motor control, individual neurons have been recorded whose activity reflects the mathematical integral of their inputs; in the absence of input, these neurons sustain activity at a level proportional to the running total of their inputs. This represents an analog form of memory whose dynamics can be conceptualized through an energy landscape with a continuum of lowest-energy states. Such continuous attractor landscapes are structurally non-robust, in seeming violation of the relative robustness of biological memory systems. In this talk, I will present and compare different biologically motivated circuit motifs for the accumulation and storage of signals in short-term memory. Challenges to generating robust memory maintenance will be highlighted and potential mechanisms for ameliorating the sensitivity of memory networks to perturbations will be discussed. Funding for this work was provided by NIH R01 MH065034, NSF IIS-1208218, Simons Foundation 324260, and a UC Davis Ophthalmology Research to Prevent Blindness Grant.

  19. Support mechanisms for cofiring secondary fuels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-12-15

    This report discusses the enabling and supporting mechanisms for coal/biomass cofiring in selected countries that have either considerable operational experience or potential in this technology. It investigates Europe, the USA, Australia and China as case studies and discusses the main supporting incentives adopted in consideration of the specific characteristics of renewable energy markets and the government’s position in clean energy and climate change in each of these countries. As such, this report provides not only a policy overview but also a collation of the measures adopted by the policymakers in each country to promote cofiring biomass in coal-fired power stations.

  20. Neural affective mechanisms predict market-level microlending

    NARCIS (Netherlands)

    A. Genevsky (Alex); B. Knutson (Brian)

    2015-01-01

    textabstractHumans sometimes share with others whom they may never meet or know, in violation of the dictates of pure self-interest. Research has not established which neuropsychological mechanisms support lending decisions, nor whether their influence extends to markets involving significant

  1. Neural mechanisms of cognitive reappraisal in remitted major depressive disorder.

    Science.gov (United States)

    Smoski, Moria J; Keng, Shian-Ling; Schiller, Crystal Edler; Minkel, Jared; Dichter, Gabriel S

    2013-10-01

    Down-regulation of negative emotions by cognitive strategies relies on prefrontal cortical modulation of limbic brain regions, and impaired frontolimbic functioning during cognitive reappraisal has been observed in affective disorders. However, no study to date has examined cognitive reappraisal in unmedicated euthymic individuals with a history of major depressive disorder relative to symptom-matched controls. Given that a history of depression is a critical risk factor for future depressive episodes, investigating the neural mechanisms of emotion regulation in remitted major depressive disorder (rMDD) may yield novel insights into depression risk. We assessed 37 individuals (18 rMDD, 19 controls) with functional magnetic resonance imaging (fMRI) during a task requiring cognitive reappraisal of sad images. Both groups demonstrated decreased self-reported negative affect after cognitive reappraisal and no group differences in the effects of cognitive reappraisal on mood were evident. Functional MRI results indicated greater paracingulate gyrus (rostral anterior cingulate cortex, Brodmann area 32) activation and decreased right midfrontal gyrus (Brodmann area 6) activation during the reappraisal of sad images. Trial-by-trial ratings of pre-regulation affect were not collected, limiting the interpretation of post-regulation negative affect scores. Results suggest that activation of rostral anterior cingulate cortex, a region linked to the prediction of antidepressant treatment response, and of the right midfrontal gyrus, a region involved in cognitive control in the context of cognitive reappraisal, may represent endophenotypic markers of future depression risk. Future prospective studies will be needed to validate the predictive utility of these neural markers. © 2013 Elsevier B.V. All rights reserved.

  2. Central chemoreceptors and neural mechanisms of cardiorespiratory control

    Directory of Open Access Journals (Sweden)

    T.S. Moreira

    2011-09-01

    Full Text Available The arterial partial pressure (P CO2 of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.

  3. Neural mechanism for binaural pitch perception via ghost stochastic resonance

    Science.gov (United States)

    Balenzuela, Pablo; García-Ojalvo, Jordi

    2005-06-01

    We present a physiologically plausible binaural mechanism for the perception of the pitch of complex sounds via ghost stochastic resonance. In this scheme, two neurons are driven by noise and a different periodic signal each (with frequencies f1=kf0 and f2=(k+1)f0, where k >1), and their outputs (plus noise) are applied synaptically to a third neuron. Our numerical results, using the Morris-Lecar neuron model with chemical synapses explicitly considered, show that intermediate noise levels enhance the response of the third neuron at frequencies close to f0, as in the cases previously described of ghost resonance. For the case of an inharmonic combination of inputs (f1=kf0+Δf and f2=(k+1)f0+Δf) noise is also seen to enhance the rates of most probable spiking for the third neuron at a frequency fr=f0+[Δf/(k+1/2)]. In addition, we show that similar resonances can be observed as a function of the synaptic time constant. The suggested ghost-resonance-based stochastic mechanism can thus arise either at the peripheral level or at a higher level of neural processing in the perception of pitch.

  4. Neural mechanisms of attentional control in mindfulness meditation

    Directory of Open Access Journals (Sweden)

    Peter eMalinowski

    2013-02-01

    Full Text Available The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

  5. Neural expert decision support system for stroke diagnosis

    Science.gov (United States)

    Kupershtein, Leonid M.; Martyniuk, Tatiana B.; Krencin, Myhail D.; Kozhemiako, Andriy V.; Bezsmertnyi, Yurii; Bezsmertna, Halyna; Kolimoldayev, Maksat; Smolarz, Andrzej; Weryńska-Bieniasz, RóŻa; Uvaysova, Svetlana

    2017-08-01

    In the work the hybrid expert system for stroke diagnosis was presented. The base of expert system consists of neural network and production rules. This program can quickly and accurately set to the patient preliminary and final diagnoses, get examination and treatment plans, print data of patient, analyze statistics data and perform parameterized search for patients.

  6. Mechanisms of Long Non-Coding RNAs in the Assembly and Plasticity of Neural Circuitry.

    Science.gov (United States)

    Wang, Andi; Wang, Junbao; Liu, Ying; Zhou, Yan

    2017-01-01

    The mechanisms underlying development processes and functional dynamics of neural circuits are far from understood. Long non-coding RNAs (lncRNAs) have emerged as essential players in defining identities of neural cells, and in modulating neural activities. In this review, we summarized latest advances concerning roles and mechanisms of lncRNAs in assembly, maintenance and plasticity of neural circuitry, as well as lncRNAs' implications in neurological disorders. We also discussed technical advances and challenges in studying functions and mechanisms of lncRNAs in neural circuitry. Finally, we proposed that lncRNA studies would advance our understanding on how neural circuits develop and function in physiology and disease conditions.

  7. Neural mechanisms of reactivation-induced updating that enhance and distort memory

    Science.gov (United States)

    St. Jacques, Peggy L.; Olm, Christopher; Schacter, Daniel L.

    2013-01-01

    We remember a considerable number of personal experiences because we are frequently reminded of them, a process known as memory reactivation. Although memory reactivation helps to stabilize and update memories, reactivation may also introduce distortions if novel information becomes incorporated with memory. Here we used functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms mediating reactivation-induced updating in memory for events experienced during a museum tour. During scanning, participants were shown target photographs to reactivate memories from the museum tour followed by a novel lure photograph from an alternate tour. Later, participants were presented with target and lure photographs and asked to determine whether the photographs showed a stop they visited during the tour. We used a subsequent memory analysis to examine neural recruitment during reactivation that was associated with later true and false memories. We predicted that the quality of reactivation, as determined by online ratings of subjective recollection, would increase subsequent true memories but also facilitate incorporation of the lure photograph, thereby increasing subsequent false memories. The fMRI results revealed that the quality of reactivation modulated subsequent true and false memories via recruitment of left posterior parahippocampal, bilateral retrosplenial, and bilateral posterior inferior parietal cortices. However, the timing of neural recruitment and the way in which memories were reactivated contributed to differences in whether memory reactivation led to distortions or not. These data reveal the neural mechanisms recruited during memory reactivation that modify how memories will be subsequently retrieved, supporting the flexible and dynamic aspects of memory. PMID:24191059

  8. [Molecular mechanism of brain regeneration and reconstruction of dopaminergic neural network in planarians].

    Science.gov (United States)

    Nishimura, Kaneyasu; Kitamura, Yoshihisa; Agata, Kiyokazu

    2008-04-01

    Recently, planarians have received much attention because of their contributions to research on the basic science of stem cell systems, neural regeneration, and regenerative medicine. Planarians can regenerate complete organs, including a well-organized central nervous system (CNS), within about 7 days. This high regenerative capacity is supported by pluripotent stem cells present in the mesenchymal space throughout the body. Interestingly, planarians can regenerate their brain via a molecular mechanism similar to that of mammalian brain development. The regeneration process of the planarian brain can be divided into five steps: (1) anterior blastema formation, (2) brain rudiment formation, (3) brain pattern formation, (4) neural network formation, and (5) functional recovery, with several kinds of genes and molecular cascades acting at each step. Recently, we have identified a planarian tyrosine hydroxylase (TH) gene, a rate-limiting enzyme for dopamine (DA) biosynthesis, and produced TH-knockdown planarians by the RNA interference technique. Studies of TH-knockdown planarians showed that DA has an important role of the modification in behavioral movement in planarians. Using monoclonal anti-planarian TH antibody, we also found that dopaminergic neurons are mainly localized in the planarian brain. When the planarian body was amputated, newly generated TH-immunopositive neurons were detected in the anterior region at day 3 of regeneration (i.e., the period of neural network formation), and the TH-immunopositive axonal and dendritic neural network in the CNS was reconstructed during day 5-7 of regeneration. In this article, recent advances in elucidating the molecular mechanism of planarian brain regeneration and dopaminergic neurons are reviewed, and its future prospects for contribution of this system to basic science and medical science research are described.

  9. [Neural mechanism underlying autistic savant and acquired savant syndrome].

    Science.gov (United States)

    Takahata, Keisuke; Kato, Motoichiro

    2008-07-01

    It is well known that the cases with savant syndrome, demonstrate outstanding mental capability despite coexisting severe mental disabilities. In many cases, savant skills are characterized by its domain-specificity, enhanced memory capability, and excessive focus on low-level perceptual processing. In addition, impaired integrative cognitive processing such as social cognition or executive function, restricted interest, and compulsive repetition of the same act are observed in savant individuals. All these are significantly relevant to the behavioral characteristics observed in individuals with autistic spectrum disorders (ASD). A neurocognitive model of savant syndrome should explain these cognitive features and the juxtaposition of outstanding talents with cognitive disabilities. In recent neuropsychological studies, Miller (1998) reported clinical cases of "acquired savant," i.e., patients who improved or newly acquired an artistic savant-like skill in the early stage of frontotemporal dementia (FTD). Although the relationship between an autistic savant and acquired savant remains to be elucidated, the advent of neuroimaging study of ASD and the clarification of FTD patients with savant-like skills may clarify the shared neural mechanisms of both types of talent. In this review, we classified current cognitive models of savant syndrome into the following 3 categories. (1) A hypermnesic model that suggests that savant skills develop from existing or dormant cognitive functions such as memory. However, recent findings obtained through neuropsychological examinations imply that savant individuals solve problems using a strategy that is fairly different from a non-autistic one. (2) A paradoxical functional facilitation model (Kapur, 1996) that offers possible explanations about how pathological states in the brain lead to development of prodigious skills. This model emphasizes the role of reciprocal inhibitory interaction among adjacent or distant cortical regions

  10. Effects of propofol on patient-ventilator synchrony and interaction during pressure support ventilation and neurally adjusted ventilatory assist.

    Science.gov (United States)

    Vaschetto, Rosanna; Cammarota, Gianmaria; Colombo, Davide; Longhini, Federico; Grossi, Francesca; Giovanniello, Andrea; Della Corte, Francesco; Navalesi, Paolo

    2014-01-01

    Evaluating the physiologic effects of varying depths of propofol sedation on patient-ventilator interaction and synchrony during pressure support ventilation and neurally adjusted ventilatory assist. Prospective crossover randomized controlled trial. University hospital ICU. Fourteen intubated patients mechanically ventilated for acute respiratory failure. Six 25-minute trials randomly performed applying both pressure support ventilation and neurally adjusted ventilatory assist during wakefulness and with two doses of propofol, administered by Target Control Infusion, determining light (1.26 ± 0.35 μg/mL) and deep (2.52 ± 0.71 μg/mL) sedation, as defined by the bispectral index and Ramsay Sedation Scale. We measured electrical activity of the diaphragm to assess neural drive and calculated its integral over time during 1 minute (∫electrical activity of the diaphragm/min) to estimate diaphragm energy expenditure (effort), arterial blood gases, airway pressure, tidal volume and its coefficient of variation, respiratory rate, neural timing components, and calculated the ineffective triggering index. Increasing the depth of sedation did not cause significant modifications of respiratory timing, while determined a progressive significant decrease in neural drive (with both modes) and effort (in pressure support ventilation only). In pressure support ventilation, the difference in ineffective triggering index between wakefulness and light sedation was negligible (from 5.9% to 7.6%, p = 0.97); with deep sedation, however, ineffective triggering index increased up to 21.8% (p ventilator interactions. In pressure support ventilation, deep propofol sedation increased asynchronies, while light sedation did not. Propofol reduced the respiratory drive, while breathing timing was not significantly affected. Gas exchange and breathing pattern were also influenced by propofol infusion to an extent that varied with the depth of sedation and the mode of ventilation.

  11. Neural mechanism underlying autobiographical memory modulated by remoteness and emotion

    Science.gov (United States)

    Ge, Ruiyang; Fu, Yan; Wang, DaHua; Yao, Li; Long, Zhiying

    2012-03-01

    Autobiographical memory is the ability to recollect past events from one's own life. Both emotional tone and memory remoteness can influence autobiographical memory retrieval along the time axis of one's life. Although numerous studies have been performed to investigate brain regions involved in retrieving processes of autobiographical memory, the effect of emotional tone and memory age on autobiographical memory retrieval remains to be clarified. Moreover, whether the involvement of hippocampus in consolidation of autobiographical events is time dependent or independent has been controversial. In this study, we investigated the effect of memory remoteness (factor1: recent and remote) and emotional valence (factor2: positive and negative) on neural correlates underlying autobiographical memory by using functional magnetic resonance imaging (fMRI) technique. Although all four conditions activated some common regions known as "core" regions in autobiographical memory retrieval, there are some other regions showing significantly different activation for recent versus remote and positive versus negative memories. In particular, we found that bilateral hippocampal regions were activated in the four conditions regardless of memory remoteness and emotional valence. Thus, our study confirmed some findings of previous studies and provided further evidence to support the multi-trace theory which believes that the role of hippocampus involved in autobiographical memory retrieval is time-independent and permanent in memory consolidation.

  12. Neural mechanisms of timing control in a coincident timing task.

    Science.gov (United States)

    Masaki, Hiroaki; Sommer, Werner; Takasawa, Noriyoshi; Yamazaki, Katuo

    2012-04-01

    Many ball sports such as tennis or baseball require precise temporal anticipation of both sensory input and motor output (i.e., receptor anticipation and effector anticipation, respectively) and close performance monitoring. We investigated the neural mechanisms underlying timing control and performance monitoring in a coincident timing task involving both types of anticipations. Peak force for two time-to-peak force (TTP) conditions-recorded with a force-sensitive key-was required to coincide with a specific position of a stimulus rotating either slow or fast on a clock face while the contingent negative variation (CNV) and the motor-elicited negativity were recorded. Absolute timing error was generally smaller for short TTP (high velocity) conditions. CNV amplitudes increased with both faster stimulus velocity and longer TTPs possibly reflecting increased motor programming efforts. In addition, the motor-elicited negativity was largest in the slow stimulus/short TTP condition, probably representing some forms of performance monitoring as well as shorter response duration. Our findings indicate that the coincident timing task is a good model for real-life situations of tool use.

  13. A neural mechanism for recognizing speech spoken by different speakers.

    Science.gov (United States)

    Kreitewolf, Jens; Gaudrain, Etienne; von Kriegstein, Katharina

    2014-05-01

    Understanding speech from different speakers is a sophisticated process, particularly because the same acoustic parameters convey important information about both the speech message and the person speaking. How the human brain accomplishes speech recognition under such conditions is unknown. One view is that speaker information is discarded at early processing stages and not used for understanding the speech message. An alternative view is that speaker information is exploited to improve speech recognition. Consistent with the latter view, previous research identified functional interactions between the left- and the right-hemispheric superior temporal sulcus/gyrus, which process speech- and speaker-specific vocal tract parameters, respectively. Vocal tract parameters are one of the two major acoustic features that determine both speaker identity and speech message (phonemes). Here, using functional magnetic resonance imaging (fMRI), we show that a similar interaction exists for glottal fold parameters between the left and right Heschl's gyri. Glottal fold parameters are the other main acoustic feature that determines speaker identity and speech message (linguistic prosody). The findings suggest that interactions between left- and right-hemispheric areas are specific to the processing of different acoustic features of speech and speaker, and that they represent a general neural mechanism when understanding speech from different speakers. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Neural Mechanisms of Positive Mood Induced Modulation of Reality Monitoring

    Science.gov (United States)

    Subramaniam, Karuna; Gill, Jeevit; Slattery, Patrick; Shastri, Aditi; Mathalon, Daniel H.; Nagarajan, Srikantan; Vinogradov, Sophia

    2016-01-01

    This study investigates the neural mechanisms of mood induced modulation of cognition, specifically, on reality monitoring abilities. Reality monitoring is the ability to accurately distinguish the source of self-generated information from externally-presented contextual information. When participants were in a positive mood, compared to a neutral mood, they significantly improved their source memory identification abilities, particularly for self-generated information. However, being in a negative mood had no effect on reality monitoring abilities. Additionally, when participants were in a positive mood state, they showed activation in several regions that predisposed them to perform better at reality monitoring. Specifically, positive mood induced activity within the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) was associated with improvements in subsequent identification of self-generated information, and positive mood induced activation within the striatum (putamen) facilitated better identification of externally-presented information. These findings indicate that regions within mPFC, PCC and striatum are sensitive to positive mood-cognition enhancing effects that enable participants to be better prepared for subsequent reality monitoring decision-making. PMID:27895571

  15. Common neural mechanisms underlying reversal learning by reward and punishment.

    Science.gov (United States)

    Xue, Gui; Xue, Feng; Droutman, Vita; Lu, Zhong-Lin; Bechara, Antoine; Read, Stephen

    2013-01-01

    Impairments in flexible goal-directed decisions, often examined by reversal learning, are associated with behavioral abnormalities characterized by impulsiveness and disinhibition. Although the lateral orbital frontal cortex (OFC) has been consistently implicated in reversal learning, it is still unclear whether this region is involved in negative feedback processing, behavioral control, or both, and whether reward and punishment might have different effects on lateral OFC involvement. Using a relatively large sample (N = 47), and a categorical learning task with either monetary reward or moderate electric shock as feedback, we found overlapping activations in the right lateral OFC (and adjacent insula) for reward and punishment reversal learning when comparing correct reversal trials with correct acquisition trials, whereas we found overlapping activations in the right dorsolateral prefrontal cortex (DLPFC) when negative feedback signaled contingency change. The right lateral OFC and DLPFC also showed greater sensitivity to punishment than did their left homologues, indicating an asymmetry in how punishment is processed. We propose that the right lateral OFC and anterior insula are important for transforming affective feedback to behavioral adjustment, whereas the right DLPFC is involved in higher level attention control. These results provide insight into the neural mechanisms of reversal learning and behavioral flexibility, which can be leveraged to understand risky behaviors among vulnerable populations.

  16. Mechanical roles of apical constriction, cell elongation, and cell migration during neural tube formation in Xenopus.

    Science.gov (United States)

    Inoue, Yasuhiro; Suzuki, Makoto; Watanabe, Tadashi; Yasue, Naoko; Tateo, Itsuki; Adachi, Taiji; Ueno, Naoto

    2016-12-01

    Neural tube closure is an important and necessary process during the development of the central nervous system. The formation of the neural tube structure from a flat sheet of neural epithelium requires several cell morphogenetic events and tissue dynamics to account for the mechanics of tissue deformation. Cell elongation changes cuboidal cells into columnar cells, and apical constriction then causes them to adopt apically narrow, wedge-like shapes. In addition, the neural plate in Xenopus is stratified, and the non-neural cells in the deep layer (deep cells) pull the overlying superficial cells, eventually bringing the two layers of cells to the midline. Thus, neural tube closure appears to be a complex event in which these three physical events are considered to play key mechanical roles. To test whether these three physical events are mechanically sufficient to drive neural tube formation, we employed a three-dimensional vertex model and used it to simulate the process of neural tube closure. The results suggest that apical constriction cued the bending of the neural plate by pursing the circumference of the apical surface of the neural cells. Neural cell elongation in concert with apical constriction further narrowed the apical surface of the cells and drove the rapid folding of the neural plate, but was insufficient for complete neural tube closure. Migration of the deep cells provided the additional tissue deformation necessary for closure. To validate the model, apical constriction and cell elongation were inhibited in Xenopus laevis embryos. The resulting cell and tissue shapes resembled the corresponding simulation results.

  17. Intelligent decision support systems for mechanical ventilation.

    Science.gov (United States)

    Tehrani, Fleur T; Roum, James H

    2008-11-01

    An overview of different methodologies used in various intelligent decision support systems (IDSSs) for mechanical ventilation is provided. The applications of the techniques are compared in view of today's intensive care unit (ICU) requirements. Information available in the literature is utilized to provide a methodological review of different systems. Comparisons are made of different systems developed for specific ventilation modes as well as those intended for use in wider applications. The inputs and the optimized parameters of different systems are discussed and rule-based systems are compared to model-based techniques. The knowledge-based systems used for closed-loop control of weaning from mechanical ventilation are also described. Finally, in view of increasing trend towards automation of mechanical ventilation, the potential utility of intelligent advisory systems for this purpose is discussed. IDSSs for mechanical ventilation can be quite helpful to clinicians in today's ICU settings. To be useful, such systems should be designed to be effective, safe, and easy to use at patient's bedside. In particular, these systems must be capable of noise removal, artifact detection and effective validation of data. Systems that can also be adapted for closed-loop control/weaning of patients at the discretion of the clinician, may have a higher potential for use in the future.

  18. Neural Mechanisms Involved in Hypersensitive Hearing: Helping Children with ASD Who Are Overly Sensitive to Sounds.

    Science.gov (United States)

    Lucker, Jay R; Doman, Alex

    2015-01-01

    Professionals working with children diagnosed with autism spectrum disorder (ASD) may find that these children are overly sensitive to sounds. These professionals are often concerned as to why children may have auditory hypersensitivities. This review article discusses the neural mechanisms identified underlying hypersensitive hearing in people. The authors focus on brain research to support the idea of the nonclassical auditory pathways being involved in connecting the auditory system with the emotional system of the brain. The authors also discuss brain mechanisms felt to be involved in auditory hypersensitivity. The authors conclude with a discussion of some treatments for hypersensitive hearing. These treatments include desensitization training and the use of listening therapies such as The Listening Program.

  19. Neural Mechanisms Involved in Hypersensitive Hearing: Helping Children with ASD Who Are Overly Sensitive to Sounds

    Directory of Open Access Journals (Sweden)

    Jay R. Lucker

    2015-01-01

    Full Text Available Professionals working with children diagnosed with autism spectrum disorder (ASD may find that these children are overly sensitive to sounds. These professionals are often concerned as to why children may have auditory hypersensitivities. This review article discusses the neural mechanisms identified underlying hypersensitive hearing in people. The authors focus on brain research to support the idea of the nonclassical auditory pathways being involved in connecting the auditory system with the emotional system of the brain. The authors also discuss brain mechanisms felt to be involved in auditory hypersensitivity. The authors conclude with a discussion of some treatments for hypersensitive hearing. These treatments include desensitization training and the use of listening therapies such as The Listening Program.

  20. The Application of Radial Basis Function (RBF) Neural Network for Mechanical Fault Diagnosis of Gearbox

    Science.gov (United States)

    Wang, Pengbo

    2017-11-01

    In this paper, the radial basis function (RBF) neural network is used for the mechanical fault diagnosis of a gearbox. We introduce the basic principles of the RBF neural network which is used for pattern classification and features a fast learning pace and strong nonlinear mapping capability; thus, it can be employed for fault diagnosis. The gearbox is a widely-used piece of equipment in engineering, and diagnosing mechanical faults is of great significance for engineers. A numerical example is presented to demonstrate the capability of the proposed method. The results indicate that the mechanical faults of a gearbox can be correctly diagnosed with a trained RBF neural network.

  1. Sensory Entrainment Mechanisms in Auditory Perception: Neural Synchronization Cortico-Striatal Activation

    Science.gov (United States)

    Sameiro-Barbosa, Catia M.; Geiser, Eveline

    2016-01-01

    The auditory system displays modulations in sensitivity that can align with the temporal structure of the acoustic environment. This sensory entrainment can facilitate sensory perception and is particularly relevant for audition. Systems neuroscience is slowly uncovering the neural mechanisms underlying the behaviorally observed sensory entrainment effects in the human sensory system. The present article summarizes the prominent behavioral effects of sensory entrainment and reviews our current understanding of the neural basis of sensory entrainment, such as synchronized neural oscillations, and potentially, neural activation in the cortico-striatal system. PMID:27559306

  2. Management of pediatric tachyarrhythmias on mechanical support.

    Science.gov (United States)

    Silva, Jennifer N A; Erickson, Christopher C; Carter, Christopher D; Greene, E Anne; Kantoch, Michal; Collins, Kathryn K; Miyake, Christina Y; Carboni, Michael P; Rhee, Edward K; Papez, Andrew; Anand, Vijay; Bowman, Tammy M; Van Hare, George F

    2014-08-01

    Pediatric patients with persistent arrhythmias may require mechanical cardiopulmonary support. We sought to classify the population, spectrum, and success of current treatment strategies. A multicenter retrospective chart review was undertaken at 11 sites. Inclusion criteria were (1) patients antiarrhythmics, with 43% requiring >1 antiarrhythmic. Amiodarone was the most frequently used medication alone or in combination. A total of 33% patients underwent electrophysiology study/transcatheter ablation. Radiofrequency ablation was successful in 9 patients on full flow extracorporeal membrane oxygenation with 3 radiofrequency-failures/conversion to cryoablation. One patient underwent primary cryoablation. A total of 15% of complications were related to electrophysiology study/ablation. At follow-up, 23 patients were alive, 8 expired, and 8 transplanted. Younger patients were more likely to require support in the presented population. Most patients were treated with antiarrhythmics and one third required electrophysiology study/ablation. Radiofrequency ablation is feasible without altering extracorporeal membrane oxygenation flows. There was a low frequency of acute adverse events in patients undergoing electrophysiology study/ablation, while on extracorporeal membrane oxygenation. © 2014 American Heart Association, Inc.

  3. Neural mechanisms of resistance to peer influence in early adolescence.

    Science.gov (United States)

    Grosbras, Marie-Helène; Jansen, Marije; Leonard, Gabriel; McIntosh, Anthony; Osswald, Katja; Poulsen, Catherine; Steinberg, Laurence; Toro, Roberto; Paus, Tomas

    2007-07-25

    During the shift from a parent-dependent child to a fully autonomous adult, peers take on a significant role in shaping the adolescent's behavior. Peer-derived influences are not always positive, however. Here, we explore neural correlates of interindividual differences in the probability of resisting peer influence in early adolescence. Using functional magnetic resonance imaging, we found striking differences between 10-year-old children with high and low resistance to peer influence in their brain activity during observation of angry hand movements and angry facial expressions: compared with subjects with low resistance to peer influence, individuals with high resistance showed a highly coordinated brain activity in neural systems underlying perception of action and decision making. These findings suggest that the probability of resisting peer influence depends on neural interactions during observation of emotion-laden actions.

  4. Predictive Acoustic Tracking with an Adaptive Neural Mechanism

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    model of the lizard peripheral auditory system to extract information regarding sound direction. This information is utilised by a neural machinery to learn the acoustic signal’s velocity through fast and unsupervised correlation-based learning adapted from differential Hebbian learning. This approach...... has previously been validated in simulation and via robotic trials to track a continuous pure tone acoustic signal with a semi-circular motion trajectory and a constant but unknown angular velocity. The neural machinery has been shown to be able to learn different target angular velocities...

  5. Mechanics of neurulation: From classical to current perspectives on the physical mechanics that shape, fold, and form the neural tube.

    Science.gov (United States)

    Vijayraghavan, Deepthi S; Davidson, Lance A

    2017-01-30

    Neural tube defects arise from mechanical failures in the process of neurulation. At the most fundamental level, formation of the neural tube relies on coordinated, complex tissue movements that mechanically transform the flat neural epithelium into a lumenized epithelial tube (Davidson, 2012). The nature of this mechanical transformation has mystified embryologists, geneticists, and clinicians for more than 100 years. Early embryologists pondered the physical mechanisms that guide this transformation. Detailed observations of cell and tissue movements as well as experimental embryological manipulations allowed researchers to generate and test elementary hypotheses of the intrinsic and extrinsic forces acting on the neural tissue. Current research has turned toward understanding the molecular mechanisms underlying neurulation. Genetic and molecular perturbation have identified a multitude of subcellular components that correlate with cell behaviors and tissue movements during neural tube formation. In this review, we focus on methods and conceptual frameworks that have been applied to the study of amphibian neurulation that can be used to determine how molecular and physical mechanisms are integrated and responsible for neurulation. We will describe how qualitative descriptions and quantitative measurements of strain, force generation, and tissue material properties as well as simulations can be used to understand how embryos use morphogenetic programs to drive neurulation. Birth Defects Research 109:153-168, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  6. Neural Mechanisms of Emotion Regulation in Autism Spectrum Disorder

    Science.gov (United States)

    Richey, J. Anthony; Damiano, Cara R.; Sabatino, Antoinette; Rittenberg, Alison; Petty, Chris; Bizzell, Josh; Voyvodic, James; Heller, Aaron S.; Coffman, Marika C.; Smoski, Moria; Davidson, Richard J.; Dichter, Gabriel S.

    2015-01-01

    Autism spectrum disorder (ASD) is characterized by high rates of comorbid internalizing and externalizing disorders. One mechanistic account of these comorbidities is that ASD is characterized by impaired emotion regulation (ER) that results in deficits modulating emotional responses. We assessed neural activation during cognitive reappraisal of…

  7. Neural mechanisms of context-driven conscious visual perception

    NARCIS (Netherlands)

    Klink, P.C.

    2011-01-01

    There is an extensive neural puzzle to be solved between the moment that patterns of light first excite the photoreceptors in our retinas and the moment that we become aware of a visual scene. The effortlessness with which the brain usually solves this puzzle indicates that there must be an

  8. Neural mechanisms of song memory formation in juvenile zebra finches

    NARCIS (Netherlands)

    Moorman, S.

    2015-01-01

    There are many parallels between the acquisition of spoken language in human infants and song learning in songbirds, at the behavioural, neural, genetic and cognitive levels. Both human infants and juvenile songbirds are able to imitate sounds from adults of the same species (often their parents),

  9. Neural networks for predictive control of the mechanism of ...

    African Journals Online (AJOL)

    In this paper, we are interested in the study of the control of orientation of a wind turbine like means of optimization of his output/input ratio (efficiency). The approach suggested is based on the neural predictive control which is justified by the randomness of the wind on the one hand, and on the other hand by the capacity of ...

  10. Neural networks supporting switching, hypothesis testing, and rule application.

    Science.gov (United States)

    Liu, Zhiya; Braunlich, Kurt; Wehe, Hillary S; Seger, Carol A

    2015-10-01

    We identified dynamic changes in recruitment of neural connectivity networks across three phases of a flexible rule learning and set-shifting task similar to the Wisconsin Card Sort Task: switching, rule learning via hypothesis testing, and rule application. During fMRI scanning, subjects viewed pairs of stimuli that differed across four dimensions (letter, color, size, screen location), chose one stimulus, and received feedback. Subjects were informed that the correct choice was determined by a simple unidimensional rule, for example "choose the blue letter". Once each rule had been learned and correctly applied for 4-7 trials, subjects were cued via either negative feedback or visual cues to switch to learning a new rule. Task performance was divided into three phases: Switching (first trial after receiving the switch cue), hypothesis testing (subsequent trials through the last error trial), and rule application (correct responding after the rule was learned). We used both univariate analysis to characterize activity occurring within specific regions of the brain, and a multivariate method, constrained principal component analysis for fMRI (fMRI-CPCA), to investigate how distributed regions coordinate to subserve different processes. As hypothesized, switching was subserved by a limbic network including the ventral striatum, thalamus, and parahippocampal gyrus, in conjunction with cortical salience network regions including the anterior cingulate and frontoinsular cortex. Activity in the ventral striatum was associated with switching regardless of how switching was cued; visually cued shifts were associated with additional visual cortical activity. After switching, as subjects moved into the hypothesis testing phase, a broad fronto-parietal-striatal network (associated with the cognitive control, dorsal attention, and salience networks) increased in activity. This network was sensitive to rule learning speed, with greater extended activity for the slowest

  11. Feasibility of Using Neural Network Models to Accelerate the Testing of Mechanical Systems

    Science.gov (United States)

    Fusaro, Robert L.

    1998-01-01

    Verification testing is an important aspect of the design process for mechanical mechanisms, and full-scale, full-length life testing is typically used to qualify any new component for use in space. However, as the required life specification is increased, full-length life tests become more costly and lengthen the development time. At the NASA Lewis Research Center, we theorized that neural network systems may be able to model the operation of a mechanical device. If so, the resulting neural network models could simulate long-term mechanical testing with data from a short-term test. This combination of computer modeling and short-term mechanical testing could then be used to verify the reliability of mechanical systems, thereby eliminating the costs associated with long-term testing. Neural network models could also enable designers to predict the performance of mechanisms at the conceptual design stage by entering the critical parameters as input and running the model to predict performance. The purpose of this study was to assess the potential of using neural networks to predict the performance and life of mechanical systems. To do this, we generated a neural network system to model wear obtained from three accelerated testing devices: 1) A pin-on-disk tribometer; 2) A line-contact rub-shoe tribometer; 3) A four-ball tribometer.

  12. Modeling the Insertion Mechanics of Flexible Neural Probes Coated with Sacrificial Polymers for Optimizing Probe Design

    Science.gov (United States)

    Singh, Sagar; Lo, Meng-Chen; Damodaran, Vinod B.; Kaplan, Hilton M.; Kohn, Joachim; Zahn, Jeffrey D.; Shreiber, David I.

    2016-01-01

    Single-unit recording neural probes have significant advantages towards improving signal-to-noise ratio and specificity for signal acquisition in brain-to-computer interface devices. Long-term effectiveness is unfortunately limited by the chronic injury response, which has been linked to the mechanical mismatch between rigid probes and compliant brain tissue. Small, flexible microelectrodes may overcome this limitation, but insertion of these probes without buckling requires supporting elements such as a stiff coating with a biodegradable polymer. For these coated probes, there is a design trade-off between the potential for successful insertion into brain tissue and the degree of trauma generated by the insertion. The objective of this study was to develop and validate a finite element model (FEM) to simulate insertion of coated neural probes of varying dimensions and material properties into brain tissue. Simulations were performed to predict the buckling and insertion forces during insertion of coated probes into a tissue phantom with material properties of brain. The simulations were validated with parallel experimental studies where probes were inserted into agarose tissue phantom, ex vivo chick embryonic brain tissue, and ex vivo rat brain tissue. Experiments were performed with uncoated copper wire and both uncoated and coated SU-8 photoresist and Parylene C probes. Model predictions were found to strongly agree with experimental results (probe length were the most important features in influencing insertion potential. The model also revealed the effects of manufacturing flaws on insertion potential. PMID:26959021

  13. WeAidU-a decision support system for myocardial perfusion images using artificial neural networks.

    Science.gov (United States)

    Ohlsson, Mattias

    2004-01-01

    This paper presents a computer-based decision support system for automated interpretation of diagnostic heart images (called WeAidU), which is made available via the Internet. The system is based on image processing techniques, artificial neural networks (ANNs) and large well-validated medical databases. We present results using artificial neural networks, and compare with two other classification methods, on a retrospective data set containing 1320 images from the clinical routine. The performance of the artificial neural networks detecting infarction and ischemia in different parts of the heart, measured as areas under the receiver operating characteristic curves, is in the range 0.83-0.96. These results indicate a high potential for the tool as a clinical decision support system.

  14. Application of structured support vector machine backpropagation to a convolutional neural network for human pose estimation.

    Science.gov (United States)

    Witoonchart, Peerajak; Chongstitvatana, Prabhas

    2017-08-01

    In this study, for the first time, we show how to formulate a structured support vector machine (SSVM) as two layers in a convolutional neural network, where the top layer is a loss augmented inference layer and the bottom layer is the normal convolutional layer. We show that a deformable part model can be learned with the proposed structured SVM neural network by backpropagating the error of the deformable part model to the convolutional neural network. The forward propagation calculates the loss augmented inference and the backpropagation calculates the gradient from the loss augmented inference layer to the convolutional layer. Thus, we obtain a new type of convolutional neural network called an Structured SVM convolutional neural network, which we applied to the human pose estimation problem. This new neural network can be used as the final layers in deep learning. Our method jointly learns the structural model parameters and the appearance model parameters. We implemented our method as a new layer in the existing Caffe library. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Phonological dyslexia and dysgraphia: cognitive mechanisms and neural substrates.

    Science.gov (United States)

    Rapcsak, Steven Z; Beeson, Pélagie M; Henry, Maya L; Leyden, Anne; Kim, Esther; Rising, Kindle; Andersen, Sarah; Cho, Hyesuk

    2009-05-01

    To examine the validity of different theoretical assumptions about the neuropsychological mechanisms and lesion correlates of phonological dyslexia and dysgraphia, we studied written and spoken language performance in a large cohort of patients with focal damage to perisylvian cortical regions implicated in phonological processing. Despite considerable variation in accuracy for both words and non-words, the majority of participants demonstrated the increased lexicality effects in reading and spelling that are considered the hallmark features of phonological dyslexia and dysgraphia. Increased lexicality effects were also documented in spoken language tasks such as oral repetition, and patients performed poorly on a battery of phonological tests that did not involve an orthographic component. Furthermore, a composite measure of general phonological ability was strongly predictive of both reading and spelling accuracy, and we obtained evidence that the continuum of severity that characterized the written language disorder of our patients was attributable to an underlying continuum of phonological impairment. Although patients demonstrated qualitatively similar deficits across measures of written and spoken language processing, there were quantitative differences in levels of performance reflecting task difficulty effects. Spelling was more severely affected than reading by the reduction in phonological capacity and this differential vulnerability accounted for occasional disparities between patterns of impairment on the two written language tasks. Our findings suggest that phonological dyslexia and dysgraphia in patients with perisylvian lesions are manifestations of a central or modality-independent phonological deficit rather than the result of damage to cognitive components dedicated to reading or spelling. Our results also provide empirical support for shared-components models of written language processing, according to which the same central cognitive systems

  16. Artificial neural networks and support vector machine in banking computer systems

    Directory of Open Access Journals (Sweden)

    Jerzy Balicki

    2013-12-01

    Full Text Available In this paper, some artificial neural networks as well as a support vector machines have been studied due to bank computer system development. These approaches with the contact-less microprocessor technologies can upsurge the bank competitiveness by adding new functionalities. Moreover, some financial crisis influences can be declines.

  17. Water demand prediction using artificial neural networks and support vector regression

    CSIR Research Space (South Africa)

    Msiza, IS

    2008-11-01

    Full Text Available comparison are Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs). In this study it was observed that ANNs perform significantly better than SVMs. This performance is measured against the generalization ability of the two techniques in water...

  18. Molecular Dynamics Simulations with Quantum Mechanics / Molecular Mechanics and Adaptive Neural Networks.

    Science.gov (United States)

    Shen, Lin; Yang, Weitao

    2018-02-13

    Direct molecular dynamics (MD) simulation with ab initio quantum mechanical and molecular mechanical (QM/MM) methods is very powerful for studying the mechanism of chemical reactions in complex environment but very time consuming. The computational cost on QM/MM calculations during MD simulations can be reduced significantly using semiempirical QM/MM methods with lower accuracy. To achieve higher accuracy at the ab initio QM/MM level, a correction on the existing semiempirical QM/MM model is an attractive way. Recently, we reported a neural network (NN) method as QM/MM-NN to predict the potential energy difference between semiempirical and ab initio QM/MM approaches. The high-level results can be obtained using neural network based on semiempirical QM/MM MD simulations, but the lack of direct MD samplings at the ab initio QM/MM level is still a deficiency that limits the applications of QM/MM-NN. In the present paper, we developed a dynamic scheme of QM/MM-NN for direct MD simulations on the NN-predicted potential energy surface to approximate ab initio QM/MM MD. Since some configurations excluded from the database for NN training were encountered during simulations, which may cause some difficulties on MD samplings, an adaptive procedure inspired by the selection scheme reported by Behler was employed with some adaptions to update NN and carry out MD iteratively. We further applied the adaptive QM/MM-NN MD method to the free energy calculation and transition path optimization on chemical reactions in water. The results at the ab initio QM/MM level can be well reproduced using this method after 2-4 iteration cycles. The saving in computational cost is about 2 orders of magnitude. It demonstrates that the QM/MM-NN with direct MD simulations has great potentials not only for the calculation of thermodynamic properties but also for the characterization of reaction dynamics, which provides a useful tool to study chemical or biochemical systems in solution or enzymes.

  19. Neural Mechanisms of Cognitive Dissonance (Revised): An EEG Study.

    Science.gov (United States)

    Colosio, Marco; Shestakova, Anna; Nikulin, Vadim V; Blagovechtchenski, Evgeny; Klucharev, Vasily

    2017-05-17

    Cognitive dissonance theory suggests that our preferences are modulated by the mere act of choosing. A choice between two similarly valued alternatives creates psychological tension (cognitive dissonance) that is reduced by a postdecisional reevaluation of the alternatives. We measured EEG of human subjects during rest and free-choice paradigm. Our study demonstrates that choices associated with stronger cognitive dissonance trigger a larger negative frontocentral evoked response similar to error-related negativity, which has in turn been implicated in general performance monitoring. Furthermore, the amplitude of the evoked response is correlated with the reevaluation of the alternatives. We also found a link between individual neural dynamics (long-range temporal correlations) of the frontocentral cortices during rest and follow-up neural and behavioral effects of cognitive dissonance. Individuals with stronger resting-state long-range temporal correlations demonstrated a greater postdecisional reevaluation of the alternatives and larger evoked brain responses associated with stronger cognitive dissonance. Thus, our results suggest that cognitive dissonance is reflected in both resting-state and choice-related activity of the prefrontal cortex as part of the general performance-monitoring circuitry. SIGNIFICANCE STATEMENT Contrary to traditional decision theory, behavioral studies repeatedly demonstrate that our preferences are modulated by the mere act of choosing. Difficult choices generate psychological (cognitive) dissonance, which is reduced by the postdecisional devaluation of unchosen options. We found that decisions associated with a higher level of cognitive dissonance elicited a stronger negative frontocentral deflection that peaked ∼60 ms after the response. This activity shares similar spatial and temporal features as error-related negativity, the electrophysiological correlate of performance monitoring. Furthermore, the frontocentral resting

  20. Neural mechanisms underlying melodic perception and memory for pitch.

    Science.gov (United States)

    Zatorre, R J; Evans, A C; Meyer, E

    1994-04-01

    The neural correlates of music perception were studied by measuring cerebral blood flow (CBF) changes with positron emission tomography (PET). Twelve volunteers were scanned using the bolus water method under four separate conditions: (1) listening to a sequence of noise bursts, (2) listening to unfamiliar tonal melodies, (3) comparing the pitch of the first two notes of the same set of melodies, and (4) comparing the pitch of the first and last notes of the melodies. The latter two conditions were designed to investigate short-term pitch retention under low or high memory load, respectively. Subtraction of the obtained PET images, superimposed on matched MRI scans, provides anatomical localization of CBF changes associated with specific cognitive functions. Listening to melodies, relative to acoustically matched noise sequences, resulted in CBF increases in the right superior temporal and right occipital cortices. Pitch judgments of the first two notes of each melody, relative to passive listening to the same stimuli, resulted in right frontal-lobe activation. Analysis of the high memory load condition relative to passive listening revealed the participation of a number of cortical and subcortical regions, notably in the right frontal and right temporal lobes, as well as in parietal and insular cortex. Both pitch judgment conditions also revealed CBF decreases within the left primary auditory cortex. We conclude that specialized neural systems in the right superior temporal cortex participate in perceptual analysis of melodies; pitch comparisons are effected via a neural network that includes right prefrontal cortex, but active retention of pitch involves the interaction of right temporal and frontal cortices.

  1. Multiple mechanisms of consciousness: the neural correlates of emotional awareness.

    Science.gov (United States)

    Amting, Jayna M; Greening, Steven G; Mitchell, Derek G V

    2010-07-28

    Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally, increased activity was observed in regions associated with facial expression processing, including the amygdala and fusiform gyrus during emotional awareness. In contrast, awareness of neutral faces and suppression of fearful faces were associated with increased activity in dorsolateral prefrontal and inferior parietal cortices. The amygdala showed increased functional connectivity with ventral visual system regions during fear awareness and increased connectivity with perigenual prefrontal cortex (pgPFC; Brodmann's area 32/10) when fear was suppressed. Despite being prioritized for awareness, emotional items were associated with reduced activity in areas considered critical for consciousness. Contributions to consciousness from bottom-up and top-down neural regions may be additive, such that increased activity in specialized regions within the extended ventral visual system may reduce demands on a frontoparietal system important for awareness. The possibility is raised that interactions between pgPFC and the amygdala, previously implicated in extinction, may also influence whether or not an emotional stimulus is accessible to consciousness.

  2. Neural representations and mechanisms for the performance of simple speech sequences.

    Science.gov (United States)

    Bohland, Jason W; Bullock, Daniel; Guenther, Frank H

    2010-07-01

    Speakers plan the phonological content of their utterances before their release as speech motor acts. Using a finite alphabet of learned phonemes and a relatively small number of syllable structures, speakers are able to rapidly plan and produce arbitrary syllable sequences that fall within the rules of their language. The class of computational models of sequence planning and performance termed competitive queuing models have followed K. S. Lashley [The problem of serial order in behavior. In L. A. Jeffress (Ed.), Cerebral mechanisms in behavior (pp. 112-136). New York: Wiley, 1951] in assuming that inherently parallel neural representations underlie serial action, and this idea is increasingly supported by experimental evidence. In this article, we developed a neural model that extends the existing DIVA model of speech production in two complementary ways. The new model includes paired structure and content subsystems [cf. MacNeilage, P. F. The frame/content theory of evolution of speech production. Behavioral and Brain Sciences, 21, 499-511, 1998 ] that provide parallel representations of a forthcoming speech plan as well as mechanisms for interfacing these phonological planning representations with learned sensorimotor programs to enable stepping through multisyllabic speech plans. On the basis of previous reports, the model's components are hypothesized to be localized to specific cortical and subcortical structures, including the left inferior frontal sulcus, the medial premotor cortex, the basal ganglia, and the thalamus. The new model, called gradient order DIVA, thus fills a void in current speech research by providing formal mechanistic hypotheses about both phonological and phonetic processes that are grounded by neuroanatomy and physiology. This framework also generates predictions that can be tested in future neuroimaging and clinical case studies.

  3. Neural Mechanisms of Circadian Regulation of Natural and Drug Reward

    Directory of Open Access Journals (Sweden)

    Lauren M. DePoy

    2017-01-01

    Full Text Available Circadian rhythms are endogenously generated near 24-hour variations of physiological and behavioral functions. In humans, disruptions to the circadian system are associated with negative health outcomes, including metabolic, immune, and psychiatric diseases, such as addiction. Animal models suggest bidirectional relationships between the circadian system and drugs of abuse, whereby desynchrony, misalignment, or disruption may promote vulnerability to drug use and the transition to addiction, while exposure to drugs of abuse may entrain, disrupt, or perturb the circadian timing system. Recent evidence suggests natural (i.e., food and drug rewards may influence overlapping neural circuitry, and the circadian system may modulate the physiological and behavioral responses to these stimuli. Environmental disruptions, such as shifting schedules or shorter/longer days, influence food and drug intake, and certain mutations of circadian genes that control cellular rhythms are associated with altered behavioral reward. We highlight the more recent findings associating circadian rhythms to reward function, linking environmental and genetic evidence to natural and drug reward and related neural circuitry.

  4. Neural Mechanisms of Emotion Regulation in Autism Spectrum Disorder.

    Science.gov (United States)

    Richey, J Anthony; Damiano, Cara R; Sabatino, Antoinette; Rittenberg, Alison; Petty, Chris; Bizzell, Josh; Voyvodic, James; Heller, Aaron S; Coffman, Marika C; Smoski, Moria; Davidson, Richard J; Dichter, Gabriel S

    2015-11-01

    Autism spectrum disorder (ASD) is characterized by high rates of comorbid internalizing and externalizing disorders. One mechanistic account of these comorbidities is that ASD is characterized by impaired emotion regulation (ER) that results in deficits modulating emotional responses. We assessed neural activation during cognitive reappraisal of faces in high functioning adults with ASD. Groups did not differ in looking time, pupilometry, or subjective ratings of faces during reappraisal. However, instructions to increase positive and negative emotional responses resulted in less increase in nucleus accumbens and amygdala activations (respectively) in the ASD group, and both regulation instructions resulted in less change in dorsolateral prefrontal cortex activation in the ASD group. Results suggest a potential mechanistic account of impaired ER in ASD.

  5. Parent Support Programs and Coping Mechanisms in NICU Parents.

    Science.gov (United States)

    Huenink, Ellen; Porterfield, Susan

    2017-04-01

    Many neonatal intensive care unit (NICU) parents experience emotional distress leading to adverse infant outcomes. Parents may not cope positively in stressful situations, and support programs often are underutilized. To determine coping mechanisms utilized by NICU parents, and types of support programs parents are likely to attend. To determine whether sociodemographic and length-of-stay differences impact coping mechanisms utilized, and types of support programs preferred. A correlational cross-sectional survey design was used. The 28-item Brief COPE tool, questions about demographics and preferred support program styles, was distributed to a convenience sample of NICU parents in a level IV NICU in the southeastern United States. One hundred one NICU parents used coping mechanisms, with acceptance emotional support, active coping, positive reframing, religion, planning, and instrumental support being the most common. Preferred support classes were infant development and talking with other NICU parents. Caucasians more commonly coped using active coping, planning, emotional support, acceptance, instrumental support, and venting compared with other races. Women utilized self-blame coping mechanisms more often compared with men. Younger parents were more likely to use venting and denial coping mechanisms. Parents with a shorter stay utilized self-distraction coping and preferred the class of talking with other parents. Support program preference, type of coping mechanism utilized, and sociodemographic factors may be used to guide the creation of NICU support programs. Additional studies are needed to determine whether support program offering according to preferences and sociodemographic characteristics increases attendance and decreases emotional distress.

  6. Neural Mechanisms of Illusory Motion: Evidence from ERP Study

    Directory of Open Access Journals (Sweden)

    Xu Y. A. N. Yun

    2011-05-01

    Full Text Available ERPs were used to examine the neural correlates of illusory motion, by presenting the Rice Wave illusion (CI, its two variants (WI and NI and a real motion video (RM. Results showed that: Firstly, RM elicited a more negative deflection than CI, NI and WI between 200–350ms. Secondly, between 500–600ms, CI elicited a more positive deflection than NI and WI, and RM elicited a more positive deflection than CI, what's more interesting was the sequential enhancement of brain activity with the corresponding motion strength. We inferred that the former component might reflect the successful encoding of the local motion signals in detectors at the lower stage; while the latter one might be involved in the intensive representations of visual input in real/illusory motion perception, this was the whole motion-signal organization in the later stage of motion perception. Finally, between 1185–1450 ms, a significant positive component was found between illusory/real motion tasks than NI (no motion. Overall, we demonstrated that there was a stronger deflection under the corresponding lager motion strength. These results reflected not only the different temporal patterns between illusory and real motion but also extending to their distinguishing working memory representation and storage.

  7. Peer influence: Neural mechanisms underlying in-group conformity

    National Research Council Canada - National Science Library

    Stallen, Mirre; Smidts, Ale; Sanfey, Alan

    2013-01-01

    .... However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI...

  8. Functioning of Neural Systems Supporting Emotion Regulation in Anxiety-Prone Individuals

    OpenAIRE

    Campbell-Sills, Laura; Simmons, Alan N.; Lovero, Kathryn L.; Rochlin, Alexis A.; Martin P Paulus; Stein, Murray B.

    2010-01-01

    Previous neuroimaging studies suggest that prefrontal cortex (PFC) modulation of the amygdala and related limbic structures is an underlying neural substrate of effortful emotion regulation. Anxiety-prone individuals experience excessive negative emotions, signaling potential dysfunction of systems supporting down-regulation of negative emotions. We examined the hypothesis that anxious individuals require increased recruitment of lateral and medial PFC to decrease negative emotions. An emotio...

  9. A Neural Path Integration Mechanism for Adaptive Vector Navigation in Autonomous Agents

    DEFF Research Database (Denmark)

    Goldschmidt, Dennis; Dasgupta, Sakyasingha; Wörgötter, Florentin

    2015-01-01

    Animals show remarkable capabilities in navigating their habitat in a fully autonomous and energy-efficient way. In many species, these capabilities rely on a process called path integration, which enables them to estimate their current location and to find their way back home after long......-distance journeys. Path integration is achieved by integrating compass and odometric cues. Here we introduce a neural path integration mechanism that interacts with a neural locomotion control to simulate homing behavior and path integration-related behaviors observed in animals. The mechanism is applied...... to a simulated sixlegged artificial agent. Input signals from an allothetic compass and odometry are sustained through leaky neural integrator circuits, which are then used to compute the home vector by local excitation-global inhibition interactions. The home vector is computed and represented in circular...

  10. An adaptive neural mechanism for acoustic motion perception with varying sparsity

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    Biological motion-sensitive neural circuits are quite adept in perceiving the relative motion of a relevant stimulus. Motion perception is a fundamental ability in neural sensory processing and crucial in target tracking tasks. Tracking a stimulus entails the ability to perceive its motion, i.......e. extracting information about its direction and velocity. Here we focus on auditory motion perception of sound stimuli, which is poorly understood as compared to its visual counterpart. In earlier work we have developed a bio-inspired neural learning mechanism for acoustic motion perception. The mechanism...... be occluded by artefacts in the environment, such as an escaping prey momentarily disappearing behind a cover of trees. This article extends the earlier work by presenting a comparative investigation of auditory motion perception for unoccluded and occluded tonal sound stimuli with a frequency of 2.2 k...

  11. Neural networks supporting autobiographical memory retrieval in post-traumatic stress disorder

    Science.gov (United States)

    Jacques, Peggy L.; Kragel, Philip A.; Rubin, David C.

    2013-01-01

    Post-traumatic stress disorder (PTSD) affects the functional recruitment and connectivity between neural regions during autobiographical memory (AM) retrieval that overlap with default and control networks. Whether such univariate changes relate to potential differences in the contribution of large-scale neural networks supporting cognition in PTSD is unknown. In the current functional MRI (fMRI) study we employ independent component analysis to examine the influence the engagement of neural networks during the recall of personal memories in PTSD (15 participants) compared to non-trauma exposed, healthy controls (14 participants). We found that the PTSD group recruited similar neural networks when compared to controls during AM recall, including default network subsystems and control networks, but there were group differences in the spatial and temporal characteristics of these networks. First, there were spatial differences in the contribution of the anterior and posterior midline across the networks, and with the amygdala in particular for the medial temporal subsystem of the default network. Second, there were temporal differences in the relationship of the medial prefrontal subsystem of the default network, with less temporal coupling of this network during AM retrieval in PTSD relative to controls. These findings suggest that spatial and temporal characteristics of the default and control networks potentially differ in PTSD versus healthy controls, and contribute to altered recall of personal memory. PMID:23483523

  12. Neural mechanisms of reinforcement learning in unmedicated patients with major depressive disorder.

    Science.gov (United States)

    Rothkirch, Marcus; Tonn, Jonas; Köhler, Stephan; Sterzer, Philipp

    2017-04-01

    According to current concepts, major depressive disorder is strongly related to dysfunctional neural processing of motivational information, entailing impairments in reinforcement learning. While computational modelling can reveal the precise nature of neural learning signals, it has not been used to study learning-related neural dysfunctions in unmedicated patients with major depressive disorder so far. We thus aimed at comparing the neural coding of reward and punishment prediction errors, representing indicators of neural learning-related processes, between unmedicated patients with major depressive disorder and healthy participants. To this end, a group of unmedicated patients with major depressive disorder (n = 28) and a group of age- and sex-matched healthy control participants (n = 30) completed an instrumental learning task involving monetary gains and losses during functional magnetic resonance imaging. The two groups did not differ in their learning performance. Patients and control participants showed the same level of prediction error-related activity in the ventral striatum and the anterior insula. In contrast, neural coding of reward prediction errors in the medial orbitofrontal cortex was reduced in patients. Moreover, neural reward prediction error signals in the medial orbitofrontal cortex and ventral striatum showed negative correlations with anhedonia severity. Using a standard instrumental learning paradigm we found no evidence for an overall impairment of reinforcement learning in medication-free patients with major depressive disorder. Importantly, however, the attenuated neural coding of reward in the medial orbitofrontal cortex and the relation between anhedonia and reduced reward prediction error-signalling in the medial orbitofrontal cortex and ventral striatum likely reflect an impairment in experiencing pleasure from rewarding events as a key mechanism of anhedonia in major depressive disorder. © The Author (2017). Published by Oxford

  13. Mechanisms and Neural Basis of Object and Pattern Recognition: A Study with Chess Experts

    Science.gov (United States)

    Bilalic, Merim; Langner, Robert; Erb, Michael; Grodd, Wolfgang

    2010-01-01

    Comparing experts with novices offers unique insights into the functioning of cognition, based on the maximization of individual differences. Here we used this expertise approach to disentangle the mechanisms and neural basis behind two processes that contribute to everyday expertise: object and pattern recognition. We compared chess experts and…

  14. Peer influence: neural mechanisms underlying in-group conformity

    NARCIS (Netherlands)

    Stallen, M.; Smidts, A.; Sanfey, A.G.

    2013-01-01

    People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI). Participants completed

  15. Peer influence: Neural mechanisms underlying in-group conformity

    NARCIS (Netherlands)

    M. Stallen (Mirre); A. Smidts (Ale); A.G. Sanfey (Alan)

    2013-01-01

    textabstractPeople often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI).

  16. Dissociable Mechanisms Supporting Awareness: The P300 and Gamma in a Linguistic Attentional Blink Task

    Science.gov (United States)

    Karns, Christina M.; Neville, Helen

    2012-01-01

    As demonstrated by the attentional blink (AB) phenomenon, awareness for attended stimuli is governed by sharp capacity limits. We used a linguistic AB task to investigate the neural mechanisms that underlie failures of awareness, examining both event-related potentials and oscillatory brain activity to correctly reported and missed second targets (T2s) presented after a correctly reported first target (T1) in a rapid visual stream of distractors. Correctly reported targets occurring at a short lag (250 ms) after T1—within the classic AB period—elicited enhanced late gamma activity relative to incorrectly reported targets but showed no P300 modulation relative to missed targets. In contrast, correctly reported targets presented at a long lag (830 ms)—outside the classic AB period—elicited a greater P300 component but did not significantly modulate oscillatory activity. This double dissociation suggests that there are multiple neural mechanisms supporting awareness that may operate in parallel. Either the P300 or the gamma can index impairment in the cascade of processing leading to a target's entry into awareness. We conclude that the P300 and gamma activity reflect functionally distinct neural mechanisms, each of which plays an independent role in awareness. PMID:22166765

  17. Peer influence: Neural mechanisms underlying in-group conformity

    Directory of Open Access Journals (Sweden)

    Mirre eStallen

    2013-03-01

    Full Text Available People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI. Participants completed a perceptual decision-making task while undergoing fMRI, during which they were exposed to the judgments of both in-group and out-group members. Our data suggest that conformity to the in-group is mediated by both positive affect as well as the cognitive capacity of perspective taking. Examining the processes that drive in-group conformity by utilizing a basic decision-making paradigm combined with neuroimaging methods provides important insights into the potential mechanisms of conformity. These results may provide an integral step in developing more effective campaigns using group conformity as a tool for behavioral change.

  18. Peer influence: neural mechanisms underlying in-group conformity.

    Science.gov (United States)

    Stallen, Mirre; Smidts, Ale; Sanfey, Alan G

    2013-01-01

    People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI). Participants completed a perceptual decision-making task while undergoing fMRI, during which they were exposed to the judgments of both in-group and out-group members. Our data suggest that conformity to the in-group is mediated by both positive affect as well as the cognitive capacity of perspective taking. Examining the processes that drive in-group conformity by utilizing a basic decision-making paradigm combined with neuroimaging methods provides important insights into the potential mechanisms of conformity. These results may provide an integral step in developing more effective campaigns using group conformity as a tool for behavioral change.

  19. Neural and Cellular Mechanisms of Fear and Extinction Memory Formation

    Science.gov (United States)

    Orsini, Caitlin A.; Maren, Stephen

    2012-01-01

    Over the course of natural history, countless animal species have evolved adaptive behavioral systems to cope with dangerous situations and promote survival. Emotional memories are central to these defense systems because they are rapidly acquired and prepare organisms for future threat. Unfortunately, the persistence and intrusion of memories of fearful experiences are quite common and can lead to pathogenic conditions, such as anxiety and phobias. Over the course of the last thirty years, neuroscientists and psychologists alike have attempted to understand the mechanisms by which the brain encodes and maintains these aversive memories. Of equal interest, though, is the neurobiology of extinction memory formation as this may shape current therapeutic techniques. Here we review the extant literature on the neurobiology of fear and extinction memory formation, with a strong focus on the cellular and molecular mechanisms underlying these processes. PMID:22230704

  20. Ventilation distribution measured with EIT at varying levels of pressure support and Neurally Adjusted Ventilatory Assist in patients with ALI.

    Science.gov (United States)

    Blankman, Paul; Hasan, Djo; van Mourik, Martijn S; Gommers, Diederik

    2013-06-01

    The purpose of this study was to compare the effect of varying levels of assist during pressure support (PSV) and Neurally Adjusted Ventilatory Assist (NAVA) on the aeration of the dependent and non-dependent lung regions by means of Electrical Impedance Tomography (EIT). We studied ten mechanically ventilated patients with Acute Lung Injury (ALI). Positive-End Expiratory Pressure (PEEP) and PSV levels were both 10 cm H₂O during the initial PSV step. Thereafter, we changed the inspiratory pressure to 15 and 5 cm H₂O during PSV. The electrical activity of the diaphragm (EAdi) during pressure support ten was used to define the initial NAVA gain (100 %). Thereafter, we changed NAVA gain to 150 and 50 %, respectively. After each step the assist level was switched back to PSV 10 cm H₂O or NAVA 100 % to get a new baseline. The EIT registration was performed continuously. Tidal impedance variation significantly decreased during descending PSV levels within patients, whereas not during NAVA. The dorsal-to-ventral impedance distribution, expressed according to the center of gravity index, was lower during PSV compared to NAVA. Ventilation contribution of the dependent lung region was equally in balance with the non-dependent lung region during PSV 5 cm H₂O, NAVA 50 and 100 %. Neurally Adjusted Ventilatory Assist ventilation had a beneficial effect on the ventilation of the dependent lung region and showed less over-assistance compared to PSV in patients with ALI.

  1. Hearing loss in older adults affects neural systems supporting speech comprehension.

    Science.gov (United States)

    Peelle, Jonathan E; Troiani, Vanessa; Grossman, Murray; Wingfield, Arthur

    2011-08-31

    Hearing loss is one of the most common complaints in adults over the age of 60 and a major contributor to difficulties in speech comprehension. To examine the effects of hearing ability on the neural processes supporting spoken language processing in humans, we used functional magnetic resonance imaging to monitor brain activity while older adults with age-normal hearing listened to sentences that varied in their linguistic demands. Individual differences in hearing ability predicted the degree of language-driven neural recruitment during auditory sentence comprehension in bilateral superior temporal gyri (including primary auditory cortex), thalamus, and brainstem. In a second experiment, we examined the relationship of hearing ability to cortical structural integrity using voxel-based morphometry, demonstrating a significant linear relationship between hearing ability and gray matter volume in primary auditory cortex. Together, these results suggest that even moderate declines in peripheral auditory acuity lead to a systematic downregulation of neural activity during the processing of higher-level aspects of speech, and may also contribute to loss of gray matter volume in primary auditory cortex. More generally, these findings support a resource-allocation framework in which individual differences in sensory ability help define the degree to which brain regions are recruited in service of a particular task.

  2. An Adaptive Neural Mechanism with a Lizard Ear Model for Binaural Acoustic Tracking

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2016-01-01

    Acoustic tracking of a moving sound source is relevant in many domains including robotic phonotaxis and human-robot interaction. Typical approaches rely on processing time-difference-of-arrival cues obtained via multi-microphone arrays with Kalman or particle filters, or other computationally...... expensive algorithms. We present a novel bioinspired solution to acoustic tracking that uses only two microphones. The system is based on a neural mechanism coupled with a model of the peripheral auditory system of lizards. The peripheral auditory model provides sound direction information which the neural...

  3. Big Multidimensional Datasets Visualization Using Neural Networks – Efficient Decision Support

    Directory of Open Access Journals (Sweden)

    Gintautas Dzemyda

    2016-04-01

    Full Text Available Nowadays business information systems are thought of as decision-oriented systems supported by different types of subsystems. Multidimensional data visualization is an essential part of such systems. As datasets tend to be increasingly large, more effective ways are required to display, analyze and interpret information they contain. Most of the classical visualization methods are unsuitable for large datasets. This paper focuses on the artificial neural networks-based methods for visualization of big multidimensional datasets; namely,  on the approaches for the faster obtaining of visual results. The new strategy, which is identified by the decreased number of cycles of data reviews (passes of training data up to the only one, when training neural networks, is proposed. To test this strategy, the results of experiments, using two unsupervised learning methods on benchmark data, are briefly presented.

  4. Neural oscillatory mechanisms during novel grammar learning underlying language analytical abilities.

    Science.gov (United States)

    Kepinska, Olga; Pereda, Ernesto; Caspers, Johanneke; Schiller, Niels O

    2017-12-01

    The goal of the present study was to investigate the initial phases of novel grammar learning on a neural level, concentrating on mechanisms responsible for individual variability between learners. Two groups of participants, one with high and one with average language analytical abilities, performed an Artificial Grammar Learning (AGL) task consisting of learning and test phases. During the task, EEG signals from 32 cap-mounted electrodes were recorded and epochs corresponding to the learning phases were analysed. We investigated spectral power modulations over time, and functional connectivity patterns by means of a bivariate, frequency-specific index of phase synchronization termed Phase Locking Value (PLV). Behavioural data showed learning effects in both groups, with a steeper learning curve and higher ultimate attainment for the highly skilled learners. Moreover, we established that cortical connectivity patterns and profiles of spectral power modulations over time differentiated L2 learners with various levels of language analytical abilities. Over the course of the task, the learning process seemed to be driven by whole-brain functional connectivity between neuronal assemblies achieved by means of communication in the beta band frequency. On a shorter time-scale, increasing proficiency on the AGL task appeared to be supported by stronger local synchronisation within the right hemisphere regions. Finally, we observed that the highly skilled learners might have exerted less mental effort, or reduced attention for the task at hand once the learning was achieved, as evidenced by the higher alpha band power. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Neural mechanisms of dissonance: an fMRI investigation of choice justification.

    Science.gov (United States)

    Kitayama, Shinobu; Chua, Hannah Faye; Tompson, Steven; Han, Shihui

    2013-04-01

    Cognitive dissonance theory proposes that difficult choice produces negatively arousing cognitive conflict (called dissonance), which motivates the chooser to justify her decision by increasing her preference for the chosen option while decreasing her preference for the rejected option. At present, however, neural mechanisms of dissonance are poorly understood. To address this gap of knowledge, we scanned 24 young Americans as they made 60 choices between pairs of popular music CDs. As predicted, choices between CDs that were close (vs. distant) in attractiveness (referred to as difficult vs. easy choices) resulted in activations of the dorsal anterior cingulate cortex (dACC), a brain region associated with cognitive conflict, and the left anterior insula (left aINS), a region often linked with aversive emotional arousal. Importantly, a separate analysis showed that choice-justifying attitude change was predicted by the in-choice signal intensity of the posterior cingulate cortex (PCC), a region that is linked to self-processing. The three regions identified (dACC, left aINS, and PCC) were correlated, within-subjects, across choices. The results were interpreted to support the hypothesis that cognitive dissonance plays a key role in producing attitudes that justify the choice. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Moral foundations in an interacting neural networks society: A statistical mechanics analysis

    Science.gov (United States)

    Vicente, R.; Susemihl, A.; Jericó, J. P.; Caticha, N.

    2014-04-01

    The moral foundations theory supports that people, across cultures, tend to consider a small number of dimensions when classifying issues on a moral basis. The data also show that the statistics of weights attributed to each moral dimension is related to self-declared political affiliation, which in turn has been connected to cognitive learning styles by the recent literature in neuroscience and psychology. Inspired by these data, we propose a simple statistical mechanics model with interacting neural networks classifying vectors and learning from members of their social neighbourhood about their average opinion on a large set of issues. The purpose of learning is to reduce dissension among agents when disagreeing. We consider a family of learning algorithms parametrized by δ, that represents the importance given to corroborating (same sign) opinions. We define an order parameter that quantifies the diversity of opinions in a group with homogeneous learning style. Using Monte Carlo simulations and a mean field approximation we find the relation between the order parameter and the learning parameter δ at a temperature we associate with the importance of social influence in a given group. In concordance with data, groups that rely more strongly on corroborating evidence sustain less opinion diversity. We discuss predictions of the model and propose possible experimental tests.

  7. Neural Acupuncture Unit: A New Concept for Interpreting Effects and Mechanisms of Acupuncture

    Science.gov (United States)

    Zhang, Zhang-Jin; Wang, Xiao-Min; McAlonan, Grainne M.

    2012-01-01

    When an acupuncture needle is inserted into a designated point on the body and mechanical or electrical stimulation is delivered, various neural and neuroactive components are activated. The collection of the activated neural and neuroactive components distributed in the skin, muscle, and connective tissues surrounding the inserted needle is defined as a neural acupuncture unit (NAU). The traditionally defined acupoints represent an anatomical landmark system that indicates local sites where NAUs may contain relatively dense and concentrated neural and neuroactive components, upon which acupuncture stimulation would elicit a more efficient therapeutic response. The NAU-based local mechanisms of biochemical and biophysical reactions play an important role in acupuncture-induced analgesia. Different properties of NAUs are associated with different components of needling sensation. There exist several central pathways to convey NAU-induced acupuncture signals, Electroacupuncture (EA) frequency-specific neurochemical effects are related to different peripheral and central pathways transmitting afferent signals from different frequency of NAU stimulation. More widespread and intense neuroimaging responses of brain regions to acupuncture may be a consequence of more efficient NAU stimulation modes. The introduction of the conception of NAU provides a new theoretical approach to interpreting effects and mechanisms of acupuncture in modern biomedical knowledge framework. PMID:22474503

  8. Believing versus interacting: Behavioural and neural mechanisms underlying interpersonal coordination

    DEFF Research Database (Denmark)

    Konvalinka, Ivana; Bauer, Markus; Kilner, James

    When two people engage in a bidirectional interaction with each other, they use both bottom-up sensorimotor mechanisms such as monitoring and adapting to the behaviour of the other, as well as top-down cognitive processes, modulating their beliefs and allowing them to make decisions. Most research...... was measured from one co-actor, with the other co-actor seated outside the scanner. Our findings show frontal alpha suppression during anticipation of the task with a person vs. a computer, and frontal-sensorimotor suppression during task execution with the person vs. computer. This provides insight...

  9. Peer influence: neural mechanisms underlying in-group conformity

    OpenAIRE

    Stallen, Mirre; Smidts, Ale; Sanfey, Alan G.

    2013-01-01

    People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI). Participants completed a perceptual decision-making task while undergoing fMRI, during which they were exposed to the judgments of both in-group and out-group members. Our data suggest that conformity to the in-group is ...

  10. Neurally adjusted ventilatory assist compared to other forms of triggered ventilation for neonatal respiratory support.

    Science.gov (United States)

    Rossor, Thomas E; Hunt, Katie A; Shetty, Sandeep; Greenough, Anne

    2017-10-27

    Effective synchronisation of infant respiratory effort with mechanical ventilation may allow adequate gas exchange to occur at lower peak airway pressures, potentially reducing barotrauma and volutrauma and development of air leaks and bronchopulmonary dysplasia. During neurally adjusted ventilatory assist ventilation (NAVA), respiratory support is initiated upon detection of an electrical signal from the diaphragm muscle, and pressure is provided in proportion to and synchronous with electrical activity of the diaphragm (EADi). Compared to other modes of triggered ventilation, this may provide advantages in improving synchrony. Primary• To determine whether NAVA, when used as a primary or rescue mode of ventilation, results in reduced rates of bronchopulmonary dysplasia (BPD) or death among term and preterm newborn infants compared to other forms of triggered ventilation• To assess the safety of NAVA by determining whether it leads to greater risk of intraventricular haemorrhage (IVH), periventricular leukomalacia, or air leaks when compared to other forms of triggered ventilation Secondary• To determine whether benefits of NAVA differ by gestational age (term or preterm)• To determine whether outcomes of cross-over trials performed during the first two weeks of life include peak pressure requirements, episodes of hypocarbia or hypercarbia, oxygenation index, and the work of breathing SEARCH METHODS: We performed searches of the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cohrane Library; MEDLINE via Ovid SP (January 1966 to March 2017); Embase via Ovid SP (January 1980 to March 2017); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host (1982 to March 2017); and the Web of Science (1985 to 2017). We searched abstracts from annual meetings of the Pediatric Academic Societies (PAS) (2000 to 2016); meetings of the European Society of Pediatric Research (published in Pediatric Research); and meetings of the

  11. Motivation and cognitive control: from behavior to neural mechanism.

    Science.gov (United States)

    Botvinick, Matthew; Braver, Todd

    2015-01-03

    Research on cognitive control and executive function has long recognized the relevance of motivational factors. Recently, however, the topic has come increasingly to center stage, with a surge of new studies examining the interface of motivation and cognitive control. In the present article we survey research situated at this interface, considering work from cognitive and social psychology and behavioral economics, but with a particular focus on neuroscience research. We organize existing findings into three core areas, considering them in the light of currently vying theoretical perspectives. Based on the accumulated evidence, we advocate for a view of control function that treats it as a domain of reward-based decision making. More broadly, we argue that neuroscientific evidence plays a critical role in understanding the mechanisms by which motivation and cognitive control interact. Opportunities for further cross-fertilization between behavioral and neuroscientific research are highlighted.

  12. Studies of Neuronal Gene Regulation Controlling the Molecular Mechanisms Underlying Neural Plasticity.

    Science.gov (United States)

    Fukuchi, Mamoru

    2017-01-01

    The regulation of the development and function of the nervous system is not preprogramed but responds to environmental stimuli to change neural development and function flexibly. This neural plasticity is a characteristic property of the nervous system. For example, strong synaptic activation evoked by environmental stimuli leads to changes in synaptic functions (known as synaptic plasticity). Long-lasting synaptic plasticity is one of the molecular mechanisms underlying long-term learning and memory. Since discovering the role of the transcription factor cAMP-response element-binding protein in learning and memory, it has been widely accepted that gene regulation in neurons contributes to long-lasting changes in neural functions. However, it remains unclear how synaptic activation is converted into gene regulation that results in long-lasting neural functions like long-term memory. We continue to address this question. This review introduces our recent findings on the gene regulation of brain-derived neurotrophic factor and discusses how regulation of the gene participates in long-lasting changes in neural functions.

  13. Using Neural Networks in Decision Making for a Reconfigurable Electro Mechanical Actuator (EMA)

    Science.gov (United States)

    Latino, Carl D.

    2001-01-01

    The objectives of this project were to demonstrate applicability and advantages of a neural network approach for evaluating the performance of an electro-mechanical actuator (EMA). The EMA in question was intended for the X-37 Advanced Technology Vehicle. It will have redundant components for safety and reliability. The neural networks for this application are to monitor the operation of the redundant electronics that control the actuator in real time and decide on the operating configuration. The system we proposed consists of the actuator, sensors, control circuitry and dedicated (embedded) processors. The main purpose of the study was to develop suitable hardware and neural network capable of allowing real time reconfiguration decisions to be made. This approach was to be compared to other methods such as fuzzy logic and knowledge based systems considered for the same application. Over the course of the project a more general objective was the identification of the other neural network applications and the education of interested NASA personnel on the topic of Neural Networks.

  14. Support Mechanisms for Renewables: How Risk Exposure Influences Investment Incentives

    DEFF Research Database (Denmark)

    Kitzing, Lena; Weber, Christoph

    2015-01-01

    We analyse quantitatively how risk exposure from different support mechanisms, such as feed-in tariffs and premiums, can influence the investment incentives for private investors. We develop a net cash flow approach that takes systematic and unsystematic risks into account through cost of capital......-in premium scheme. The effect of differences in risk exposure from the support schemes is significant and cannot be neglected in policy making, especially when deciding between support instruments or when determining adequate support levels....

  15. Which neural mechanisms mediate the effects of a parenting intervention program on parenting behavior: design of a randomized controlled trial.

    Science.gov (United States)

    Kolijn, Laura; Euser, Saskia; van den Bulk, Bianca G; Huffmeijer, Renske; van IJzendoorn, Marinus H; Bakermans-Kranenburg, Marian J

    2017-03-21

    The Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) has proven effective in increasing parental sensitivity. However, the mechanisms involved are largely unknown. In a randomized controlled trial we examine parental neurocognitive factors that may mediate the intervention effects on parenting behavior. Our aims are to (1) examine whether the intervention influences parents' neural processing of children's emotional expressions and the neural precursors of response inhibition and to (2) test whether neural changes mediate intervention effects on parenting behavior. We will test 100 mothers of 4-6 year old same-sex twins. A random half of the mothers will receive the VIPP-SD Twins (i.e. VIPP-SD adapted for twin families), consisting of 5 home visits in a 3-months period; the other half will receive a dummy intervention. Neurocognitive measures are acquired approximately 2 weeks before and 2 weeks after the intervention. Mothers' electroencephalographic (EEG) activity is measured while performing a stop signal task and in response to children's facial expressions. To obtain a complementary behavioral measure, mothers also perform an emotion recognition task. Parenting behavior will be assessed during parent-child interactions at pre and post intervention lab visits. Our results will shed light on the neurocognitive factors underlying changes in parenting behavior after a parenting support program, which may benefit the development of such programs. Dutch Trial Register: NTR5312 ; Date registered: January 3, 2017.

  16. Developmental differences in the neural mechanisms of facial emotion labeling

    Science.gov (United States)

    Adleman, Nancy E.; Kim, Pilyoung; Oakes, Allison H.; Hsu, Derek; Reynolds, Richard C.; Chen, Gang; Pine, Daniel S.; Brotman, Melissa A.; Leibenluft, Ellen

    2016-01-01

    Adolescence is a time of increased risk for the onset of psychological disorders associated with deficits in face emotion labeling. We used functional magnetic resonance imaging (fMRI) to examine age-related differences in brain activation while adolescents and adults labeled the emotion on fearful, happy and angry faces of varying intensities [0% (i.e. neutral), 50%, 75%, 100%]. Adolescents and adults did not differ on accuracy to label emotions. In the superior temporal sulcus, ventrolateral prefrontal cortex and middle temporal gyrus, adults show an inverted-U-shaped response to increasing intensities of fearful faces and a U-shaped response to increasing intensities of happy faces, whereas adolescents show the opposite patterns. In addition, adults, but not adolescents, show greater inferior occipital gyrus activation to negative (angry, fearful) vs positive (happy) emotions. In sum, when subjects classify subtly varying facial emotions, developmental differences manifest in several ‘ventral stream’ brain regions. Charting the typical developmental course of the brain mechanisms of socioemotional processes, such as facial emotion labeling, is an important focus for developmental psychopathology research. PMID:26245836

  17. Neural mechanisms of childhood-onset bipolar illness.

    Science.gov (United States)

    Post, R M; Leverich, G S; Speer, A M; Xing, G; Weiss, S R

    2000-09-01

    Substantial evidence exists for a cohort effect (earlier onset and increased prevalence) for both unipolar and bipolar affective disorder in every generation born since World War II. This effect could be related to inherited mechanisms (e.g., bi-Hneal pedigrees or genetic anticipation) or to environmental/experiential effects on gene expression (e.g., stressor effects on the induction of transcription and growth factors, enzymes, hormones and their receptors, and signal transduction molecules) as documented in preclinical models of neonatal maternal separation. This laboratory evidence is summarized and new clinical data on the impact of severe stressors on the unfolding course of bipolar illness are noted. The reported occurrence of childhood or adolescent physical or sexual abuse, compared to those who report their absence, is associated with: earlier bipolar illness onset; faster cycling (including ultradian) patterns; increased Axis I and II comorbidities; and increased time ill in a prospective year of follow-up. Selectively, physical abuse was associated with a reported pattern of increasingly severe mania and sexual abuse with increased numbers of serious suicide attempts. In a retrospective survey of parents of children with an approximate average age of 13 who were diagnosed with bipolar illness (compared to those with other diagnoses and those with no diagnosis), a cluster of symptoms related to irritability and dyscontrol differentiated the bipolar children earliest. These symptoms included: temper tantrums, irritability, inattention, hyperactivity, impulsivity, poor frustration tolerance, and increased aggression. Given the growing evidence that episodes of affective dysfunction can not only convey morbidity and mortality, but may also sensitize to further recurrence and thus change the course of illness, opportunities abound for early recognition and intervention in childhood onset bipolar illness. Such a successful endeavor would both allow a more

  18. An auditory neural correlate suggests a mechanism underlying holistic pitch perception.

    Directory of Open Access Journals (Sweden)

    Daryl Wile

    Full Text Available Current theories of auditory pitch perception propose that cochlear place (spectral and activity timing pattern (temporal information are somehow combined within the brain to produce holistic pitch percepts, yet the neural mechanisms for integrating these two kinds of information remain obscure. To examine this process in more detail, stimuli made up of three pure tones whose components are individually resolved by the peripheral auditory system, but that nonetheless elicit a holistic, "missing fundamental" pitch percept, were played to human listeners. A technique was used to separate neural timing activity related to individual components of the tone complexes from timing activity related to an emergent feature of the complex (the envelope, and the region of the tonotopic map where information could originate from was simultaneously restricted by masking noise. Pitch percepts were mirrored to a very high degree by a simple combination of component-related and envelope-related neural responses with similar timing that originate within higher-frequency regions of the tonotopic map where stimulus components interact. These results suggest a coding scheme for holistic pitches whereby limited regions of the tonotopic map (spectral places carrying envelope- and component-related activity with similar timing patterns selectively provide a key source of neural pitch information. A similar mechanism of integration between local and emergent object properties may contribute to holistic percepts in a variety of sensory systems.

  19. Theory of mind in schizophrenia: exploring neural mechanisms of belief attribution.

    Science.gov (United States)

    Lee, Junghee; Quintana, Javier; Nori, Poorang; Green, Michael F

    2011-01-01

    Although previous behavioral studies have shown that schizophrenia patients have impaired theory of mind (ToM), the neural mechanisms associated with this impairment are poorly understood. This study aimed to identify the neural mechanisms of ToM in schizophrenia, using functional magnetic resonance imaging (fMRI) with a belief attribution task. In the scanner, 12 schizophrenia patients and 13 healthy control subjects performed the belief attribution task with three conditions: a false belief condition, a false photograph condition, and a simple reading condition. For the false belief versus simple reading conditions, schizophrenia patients showed reduced neural activation in areas including the temporoparietal junction (TPJ) and medial prefrontal cortex (MPFC) compared with controls. Further, during the false belief versus false photograph conditions, we observed increased activations in the TPJ and the MPFC in healthy controls, but not in schizophrenia patients. For the false photograph versus simple reading condition, both groups showed comparable neural activations. Schizophrenia patients showed reduced task-related activation in the TPJ and the MPFC during the false belief condition compared with controls, but not for the false photograph condition. This pattern suggests that reduced activation in these regions is associated with, and specific to, impaired ToM in schizophrenia.

  20. The influence of personality on neural mechanisms of observational fear and reward learning.

    Science.gov (United States)

    Hooker, Christine I; Verosky, Sara C; Miyakawa, Asako; Knight, Robert T; D'Esposito, Mark

    2008-09-01

    Fear and reward learning can occur through direct experience or observation. Both channels can enhance survival or create maladaptive behavior. We used fMRI to isolate neural mechanisms of observational fear and reward learning and investigate whether neural response varied according to individual differences in neuroticism and extraversion. Participants learned object-emotion associations by observing a woman respond with fearful (or neutral) and happy (or neutral) facial expressions to novel objects. The amygdala-hippocampal complex was active when learning the object-fear association, and the hippocampus was active when learning the object-happy association. After learning, objects were presented alone; amygdala activity was greater for the fear (vs. neutral) and happy (vs. neutral) associated object. Importantly, greater amygdala-hippocampal activity during fear (vs. neutral) learning predicted better recognition of learned objects on a subsequent memory test. Furthermore, personality modulated neural mechanisms of learning. Neuroticism positively correlated with neural activity in the amygdala and hippocampus during fear (vs. neutral) learning. Low extraversion/high introversion was related to faster behavioral predictions of the fearful and neutral expressions during fear learning. In addition, low extraversion/high introversion was related to greater amygdala activity during happy (vs. neutral) learning, happy (vs. neutral) object recognition, and faster reaction times for predicting happy and neutral expressions during reward learning. These findings suggest that neuroticism is associated with an increased sensitivity in the neural mechanism for fear learning which leads to enhanced encoding of fear associations, and that low extraversion/high introversion is related to enhanced conditionability for both fear and reward learning.

  1. The mechanisms underpinning peer support: a literature review.

    Science.gov (United States)

    Watson, Emma

    2017-12-20

    The employment of Peer Support Workers, who themselves have experience of significant emotional distress, can promote recovery at an individual and organisational level. While research examining the benefits of peer support within mental health services continues to grow, an understanding of how, and through what processes, these benefits are reached remains under-developed. To review the published research literature relating to the process of peer support and its underpinning mechanisms to better understand how and why it works. A scoping review of published literature identified studies relating to peer support mechanisms, processes and relationships. Studies were summarised and findings analysed. Five mechanisms were found to underpin peer support relationships (lived experience, love labour, the liminal position of the peer worker, strengths-focussed social and practical support, and the helper role). The identified mechanisms can underpin both the success and difficulties associated with peer support relationships. Further research should review a broader range of literature and clarify how these mechanisms contribute to peer support in different contexts.

  2. Modeling the Insertion Mechanics of Flexible Neural Probes Coated with Sacrificial Polymers for Optimizing Probe Design

    Directory of Open Access Journals (Sweden)

    Sagar Singh

    2016-03-01

    Full Text Available Single-unit recording neural probes have significant advantages towards improving signal-to-noise ratio and specificity for signal acquisition in brain-to-computer interface devices. Long-term effectiveness is unfortunately limited by the chronic injury response, which has been linked to the mechanical mismatch between rigid probes and compliant brain tissue. Small, flexible microelectrodes may overcome this limitation, but insertion of these probes without buckling requires supporting elements such as a stiff coating with a biodegradable polymer. For these coated probes, there is a design trade-off between the potential for successful insertion into brain tissue and the degree of trauma generated by the insertion. The objective of this study was to develop and validate a finite element model (FEM to simulate insertion of coated neural probes of varying dimensions and material properties into brain tissue. Simulations were performed to predict the buckling and insertion forces during insertion of coated probes into a tissue phantom with material properties of brain. The simulations were validated with parallel experimental studies where probes were inserted into agarose tissue phantom, ex vivo chick embryonic brain tissue, and ex vivo rat brain tissue. Experiments were performed with uncoated copper wire and both uncoated and coated SU-8 photoresist and Parylene C probes. Model predictions were found to strongly agree with experimental results (<10% error. The ratio of the predicted buckling force-to-predicted insertion force, where a value greater than one would ideally be expected to result in successful insertion, was plotted against the actual success rate from experiments. A sigmoidal relationship was observed, with a ratio of 1.35 corresponding to equal probability of insertion and failure, and a ratio of 3.5 corresponding to a 100% success rate. This ratio was dubbed the “safety factor”, as it indicated the degree to which the coating

  3. Neural mechanisms controlling seasonal reproduction: principles derived from the sheep model and its comparison with hamsters

    Science.gov (United States)

    Weems, Peyton W.; Goodman, Robert L.; Lehman, Michael N.

    2015-01-01

    Seasonal reproduction is a common adaptive strategy among mammals that allows for breeding to occur at times of the year when it is most advantageous for the subsequent survival and growth of offspring. A major mechanism responsible for seasonal reproduction is a striking increase in the responsiveness of gonadotropin-releasing hormone (GnRH) neurons to the negative feedback effects of estradiol. The neural and neuroendocrine circuitry responsible for mammalian seasonal reproduction has been primarily studied in three animal models: the sheep, and two species of hamsters. In this review, we first describe the afferent signals, neural circuitry and transmitters/peptides responsible for seasonal reproductive transitions in sheep, and then compare these mechanisms with those derived from studies in hamsters. The results suggest common principles as well as differences in the role of specific brain nuclei and neuropeptides, including that of kisspeptin cells of the hypothalamic arcuate nucleus, in regulating seasonal reproduction among mammals. PMID:25582913

  4. Predictive Modeling of Mechanical Properties of Welded Joints Based on Dynamic Fuzzy RBF Neural Network

    Directory of Open Access Journals (Sweden)

    ZHANG Yongzhi

    2016-10-01

    Full Text Available A dynamic fuzzy RBF neural network model was built to predict the mechanical properties of welded joints, and the purpose of the model was to overcome the shortcomings of static neural networks including structural identification, dynamic sample training and learning algorithm. The structure and parameters of the model are no longer head of default, dynamic adaptive adjustment in the training, suitable for dynamic sample data for learning, learning algorithm introduces hierarchical learning and fuzzy rule pruning strategy, to accelerate the training speed of model and make the model more compact. Simulation of the model was carried out by using three kinds of thickness and different process TC4 titanium alloy TIG welding test data. The results show that the model has higher prediction accuracy, which is suitable for predicting the mechanical properties of welded joints, and has opened up a new way for the on-line control of the welding process.

  5. Neural mechanisms underlying the integration of situational information into attribution outcomes

    OpenAIRE

    Brosch, Tobias; Schiller, Daniela; Mojdehbakhsh, Rachel; Uleman, James S.; Phelps, Elizabeth A.

    2013-01-01

    When forming impressions and trying to figure out why other people behave the way they do, we should take into account not only dispositional factors (i.e. personality traits) but also situational constraints as potential causes for a behavior. However, in their attributions, people often ignore the importance of situational factors. To investigate the neural mechanisms underlying the integration of situational information into attributions, we decomposed the attribution process by separately...

  6. An Integrative Model for the Neural Mechanism of Eye Movement Desensitization and Reprocessing (EMDR)

    OpenAIRE

    Coubard, Olivier A.

    2016-01-01

    Since the seminal report by Shapiro that bilateral stimulation induces cognitive and emotional changes, twenty-six years of basic and clinical research have examined the effects of Eye Movement Desensitization and Reprocessing (EMDR) in anxiety disorders, particularly in Post-Traumatic Stress Disorder (PTSD). The present article aims at better understanding EMDR neural mechanism. I first review procedural aspects of EMDR protocol and theoretical hypothesis about EMDR effects, and develop the ...

  7. Neural mechanisms underlying cognitive control of men with lifelong antisocial behavior.

    Science.gov (United States)

    Schiffer, Boris; Pawliczek, Christina; Mu Ller, Bernhard; Forsting, Michael; Gizewski, Elke; Leygraf, Norbert; Hodgins, Sheilagh

    2014-04-30

    Results of meta-analyses suggested subtle deficits in cognitive control among antisocial individuals. Because almost all studies focused on children with conduct problems or adult psychopaths, however, little is known about cognitive control mechanisms among the majority of persistent violent offenders who present an antisocial personality disorder (ASPD). The present study aimed to determine whether offenders with ASPD, relative to non-offenders, display dysfunction in the neural mechanisms underlying cognitive control and to assess the extent to which these dysfunctions are associated with psychopathic traits and trait impulsivity. Participants comprised 21 violent offenders and 23 non-offenders who underwent event-related functional magnetic resonance imaging while performing a non-verbal Stroop task. The offenders, relative to the non-offenders, exhibited reduced response time interference and a different pattern of conflict- and error-related activity in brain areas involved in cognitive control, attention, language, and emotion processing, that is, the anterior cingulate, dorsolateral prefrontal, superior temporal and postcentral cortices, putamen, thalamus, and amygdala. Moreover, between-group differences in behavioural and neural responses revealed associations with core features of psychopathy and attentional impulsivity. Thus, the results of the present study confirmed the hypothesis that offenders with ASPD display alterations in the neural mechanisms underlying cognitive control and that those alterations relate, at least in part, to personality characteristics. Copyright © 2014. Published by Elsevier Ireland Ltd.

  8. Neural mechanisms underlying transcranial direct current stimulation in aphasia: A feasibility study.

    Directory of Open Access Journals (Sweden)

    Lena eUlm

    2015-10-01

    Full Text Available Little is known about the neural mechanisms by which transcranial direct current stimulation (tDCS impacts on language processing in post-stroke aphasia. This was addressed in a proof-of-principle study that explored the effects of tDCS application in aphasia during simultaneous functional magnetic resonance imaging (fMRI. We employed a single subject, cross-over, sham-tDCS controlled design and the stimulation was administered to an individualized perilesional stimulation site that was identified by a baseline fMRI scan and a picture naming task. Peak activity during the baseline scan was located in the spared left inferior frontal gyrus (IFG and this area was stimulated during a subsequent cross-over phase. tDCS was successfully administered to the target region and anodal- vs. sham-tDCS resulted in selectively increased activity at the stimulation site. Our results thus demonstrate that it is feasible to precisely target an individualized stimulation site in aphasia patients during simultaneous fMRI which allows assessing the neural mechanisms underlying tDCS application. The functional imaging results of this case report highlight one possible mechanism that may have contributed to beneficial behavioural stimulation effects in previous clinical tDCS trials in aphasia. In the future, this approach will allow identifying distinct patterns of stimulation effects on neural processing in larger cohorts of patients. This may ultimately yield information about the variability of tDCS-effects on brain functions in aphasia.

  9. CLASSIFICATION OF ENTREPRENEURIAL INTENTIONS BY NEURAL NETWORKS, DECISION TREES AND SUPPORT VECTOR MACHINES

    Directory of Open Access Journals (Sweden)

    Marijana Zekić-Sušac

    2010-12-01

    Full Text Available Entrepreneurial intentions of students are important to recognize during the study in order to provide those students with educational background that will support such intentions and lead them to successful entrepreneurship after the study. The paper aims to develop a model that will classify students according to their entrepreneurial intentions by benchmarking three machine learning classifiers: neural networks, decision trees, and support vector machines. A survey was conducted at a Croatian university including a sample of students at the first year of study. Input variables described students’ demographics, importance of business objectives, perception of entrepreneurial carrier, and entrepreneurial predispositions. Due to a large dimension of input space, a feature selection method was used in the pre-processing stage. For comparison reasons, all tested models were validated on the same out-of-sample dataset, and a cross-validation procedure for testing generalization ability of the models was conducted. The models were compared according to its classification accuracy, as well according to input variable importance. The results show that although the best neural network model produced the highest average hit rate, the difference in performance is not statistically significant. All three models also extract similar set of features relevant for classifying students, which can be suggested to be taken into consideration by universities while designing their academic programs.

  10. Electrocardiogram Pattern Recognition and Analysis Based on Artificial Neural Networks and Support Vector Machines: A Review

    Directory of Open Access Journals (Sweden)

    Mario Sansone

    2013-01-01

    Full Text Available Computer systems for Electrocardiogram (ECG analysis support the clinician in tedious tasks (e.g., Holter ECG monitored in Intensive Care Units or in prompt detection of dangerous events (e.g., ventricular fibrillation. Together with clinical applications (arrhythmia detection and heart rate variability analysis, ECG is currently being investigated in biometrics (human identification, an emerging area receiving increasing attention. Methodologies for clinical applications can have both differences and similarities with respect to biometrics. This paper reviews methods of ECG processing from a pattern recognition perspective. In particular, we focus on features commonly used for heartbeat classification. Considering the vast literature in the field and the limited space of this review, we dedicated a detailed discussion only to a few classifiers (Artificial Neural Networks and Support Vector Machines because of their popularity; however, other techniques such as Hidden Markov Models and Kalman Filtering will be also mentioned.

  11. Neural mechanisms underlying the conditioned diminution of the unconditioned fear response.

    Science.gov (United States)

    Wood, Kimberly H; Ver Hoef, Lawrence W; Knight, David C

    2012-03-01

    Recognizing cues that predict an aversive event allows one to react more effectively under threatening conditions, and minimizes the reaction to the threat itself. This is demonstrated during Pavlovian fear conditioning when the unconditioned response (UCR) to a predictable unconditioned stimulus (UCS) is diminished compared to the UCR to an unpredictable UCS. The present study investigated the functional magnetic resonance imaging (fMRI) signal response associated with Pavlovian conditioned UCR diminution to better understand the relationship between individual differences in behavior and the neural mechanisms of the threat-related emotional response. Healthy volunteers participated in a fear conditioning study in which trait anxiety, skin conductance response (SCR), UCS expectancy, and the fMRI signal were assessed. During acquisition trials, a tone (CS+) was paired with a white noise UCS and a second tone (CS-) was presented without the UCS. Test trials consisted of the CS+ paired with the UCS, CS- paired with the UCS, and presentations of the UCS alone to assess conditioned UCR diminution. UCR diminution was observed within the dorsolateral PFC, dorsomedial PFC, cingulate cortex, inferior parietal lobule (IPL), anterior insula, and amygdala. The threat-related activity within the dorsolateral PFC, dorsomedial PFC, posterior cingulate cortex, and IPL varied with individual differences in trait anxiety. In addition, anticipatory (i.e. CS elicited) activity within the PFC showed an inverse relationship with threat-related (i.e. UCS elicited) activity within the PFC, IPL, and amygdala. Further, the emotional response (indexed via SCR) elicited by the threat was closely linked to amygdala activity. These findings are consistent with the view that the amygdala and PFC support learning-related processes that influence the emotional response evoked by a threat. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Feed-Forward Neural Network Prediction of the Mechanical Properties of Sandcrete Materials.

    Science.gov (United States)

    Asteris, Panagiotis G; Roussis, Panayiotis C; Douvika, Maria G

    2017-06-09

    This work presents a soft-sensor approach for estimating critical mechanical properties of sandcrete materials. Feed-forward (FF) artificial neural network (ANN) models are employed for building soft-sensors able to predict the 28-day compressive strength and the modulus of elasticity of sandcrete materials. To this end, a new normalization technique for the pre-processing of data is proposed. The comparison of the derived results with the available experimental data demonstrates the capability of FF ANNs to predict with pinpoint accuracy the mechanical properties of sandcrete materials. Furthermore, the proposed normalization technique has been proven effective and robust compared to other normalization techniques available in the literature.

  13. Distinct regulatory mechanisms act to establish and maintain Pax3 expression in the developing neural tube.

    Directory of Open Access Journals (Sweden)

    Steven Moore

    Full Text Available Pattern formation in developing tissues is driven by the interaction of extrinsic signals with intrinsic transcriptional networks that together establish spatially and temporally restricted profiles of gene expression. How this process is orchestrated at the molecular level by genomic cis-regulatory modules is one of the central questions in developmental biology. Here we have addressed this by analysing the regulation of Pax3 expression in the context of the developing spinal cord. Pax3 is induced early during neural development in progenitors of the dorsal spinal cord and is maintained as pattern is subsequently elaborated, resulting in the segregation of the tissue into dorsal and ventral subdivisions. We used a combination of comparative genomics and transgenic assays to define and dissect several functional cis-regulatory modules associated with the Pax3 locus. We provide evidence that the coordinated activity of two modules establishes and refines Pax3 expression during neural tube development. Mutational analyses of the initiating element revealed that in addition to Wnt signaling, Nkx family homeodomain repressors restrict Pax3 transcription to the presumptive dorsal neural tube. Subsequently, a second module mediates direct positive autoregulation and feedback to maintain Pax3 expression. Together, these data indicate a mechanism by which transient external signals are converted into a sustained expression domain by the activities of distinct regulatory elements. This transcriptional logic differs from the cross-repression that is responsible for the spatiotemporal patterns of gene expression in the ventral neural tube, suggesting that a variety of circuits are deployed within the neural tube regulatory network to establish and elaborate pattern formation.

  14. Neural Mechanisms of Information Storage in Visual Short-Term Memory

    Science.gov (United States)

    Serences, John T.

    2016-01-01

    The capacity to briefly memorize fleeting sensory information supports visual search and behavioral interactions with relevant stimuli in the environment. Traditionally, studies investigating the neural basis of visual short term memory (STM) have focused on the role of prefrontal cortex (PFC) in exerting executive control over what information is stored and how it is adaptively used to guide behavior. However, the neural substrates that support the actual storage of content-specific information in STM are more controversial, with some attributing this function to PFC and others to the specialized areas of early visual cortex that initially encode incoming sensory stimuli. In contrast to these traditional views, I will review evidence suggesting that content-specific information can be flexibly maintained in areas across the cortical hierarchy ranging from early visual cortex to PFC. While the factors that determine exactly where content-specific information is represented are not yet entirely clear, recognizing the importance of task-demands and better understanding the operation of non-spiking neural codes may help to constrain new theories about how memories are maintained at different resolutions, across different timescales, and in the presence of distracting information. PMID:27668990

  15. Insights into the mechanism(s) of von Willebrand factor degradation during mechanical circulatory support.

    Science.gov (United States)

    Bartoli, Carlo R; Dassanayaka, Sujith; Brittian, Kenneth R; Luckett, Andrew; Sithu, Srinivas; Siess, Thorsten; Raess, Daniel H; Spence, Paul A; Koenig, Steven C; Dowling, Robert D; D'Souza, Stanley E

    2014-05-01

    Left ventricular assist device support produces a bleeding diathesis. Evidence suggests a major role for von Willebrand factor (vWF). We examined vWF metabolism in a preclinical model of short-term mechanical circulatory support. In 25 calves (weight, 80-110 kg), the inflow/outflow graft of the Symphony Heart Assist System was sewn end-to-side to the carotid artery. Support was initiated (acute, n = 4; 1 week, n = 16; 2 weeks, n = 5). Acutely, carotid artery pressure and flow were measured to evaluate the hemodynamic changes near the anastomosis. At baseline and after ≤2 weeks of support, platelet aggregometry with adenosine 5'-diphosphate, collagen, and ristocetin was performed. Gel electrophoresis and wet immunoblotting qualitatively evaluated vWF multimers and quantified plasma ADAMTS-13, the vWF-cleaving protease. Carotid arterial rings near the anastomosis were studied with immunohistochemical staining for ADAMTS-13 and were cultured to quantify endothelial ADAMTS-13 production. Fluorescent resonance energy transfer was used to evaluate the enzymatic activity of ADAMTS-13 in the plasma and in supernatant from cultured carotid arterial rings. Plasma interleukin-6, which inhibits ADAMTS-13 activity, was measured using an enzyme-linked immunosorbent assay. During support, statistically significant (P < .05) changes in the carotid endothelium arterial hemodynamics were observed. The highest molecular weight vWF multimers were absent, and the vWF-ristocetin platelet aggregation pathway was significantly impaired. A modest but significant increase in plasma ADAMTS-13 protein and activity was observed. ADAMTS-13 decreased significantly in the carotid near the anastomosis but increased significantly in supernatant from cultured carotid arterial rings. The plasma interleukin-6 levels did not change significantly. Hemodynamic activation of vWF and increased plasma ADAMTS-13 activity may have reduced high-molecular-weight vWF multimers and thereby impaired the

  16. Fast Prediction of HCCI Combustion with an Artificial Neural Network Linked to a Fluid Mechanics Code

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Flowers, D L; Chen, J; Babaimopoulos, A

    2006-08-29

    We have developed an artificial neural network (ANN) based combustion model and have integrated it into a fluid mechanics code (KIVA3V) to produce a new analysis tool (titled KIVA3V-ANN) that can yield accurate HCCI predictions at very low computational cost. The neural network predicts ignition delay as a function of operating parameters (temperature, pressure, equivalence ratio and residual gas fraction). KIVA3V-ANN keeps track of the time history of the ignition delay during the engine cycle to evaluate the ignition integral and predict ignition for each computational cell. After a cell ignites, chemistry becomes active, and a two-step chemical kinetic mechanism predicts composition and heat generation in the ignited cells. KIVA3V-ANN has been validated by comparison with isooctane HCCI experiments in two different engines. The neural network provides reasonable predictions for HCCI combustion and emissions that, although typically not as good as obtained with the more physically representative multi-zone model, are obtained at a much reduced computational cost. KIVA3V-ANN can perform reasonably accurate HCCI calculations while requiring only 10% more computational effort than a motored KIVA3V run. It is therefore considered a valuable tool for evaluation of engine maps or other performance analysis tasks requiring multiple individual runs.

  17. Neural systems supporting linguistic structure, linguistic experience, and symbolic communication in sign language and gesture.

    Science.gov (United States)

    Newman, Aaron J; Supalla, Ted; Fernandez, Nina; Newport, Elissa L; Bavelier, Daphne

    2015-09-15

    Sign languages used by deaf communities around the world possess the same structural and organizational properties as spoken languages: In particular, they are richly expressive and also tightly grammatically constrained. They therefore offer the opportunity to investigate the extent to which the neural organization for language is modality independent, as well as to identify ways in which modality influences this organization. The fact that sign languages share the visual-manual modality with a nonlinguistic symbolic communicative system-gesture-further allows us to investigate where the boundaries lie between language and symbolic communication more generally. In the present study, we had three goals: to investigate the neural processing of linguistic structure in American Sign Language (using verbs of motion classifier constructions, which may lie at the boundary between language and gesture); to determine whether we could dissociate the brain systems involved in deriving meaning from symbolic communication (including both language and gesture) from those specifically engaged by linguistically structured content (sign language); and to assess whether sign language experience influences the neural systems used for understanding nonlinguistic gesture. The results demonstrated that even sign language constructions that appear on the surface to be similar to gesture are processed within the left-lateralized frontal-temporal network used for spoken languages-supporting claims that these constructions are linguistically structured. Moreover, although nonsigners engage regions involved in human action perception to process communicative, symbolic gestures, signers instead engage parts of the language-processing network-demonstrating an influence of experience on the perception of nonlinguistic stimuli.

  18. Normative data on development of neural and behavioral mechanisms underlying attention orienting toward social-emotional stimuli: An exploratory study

    OpenAIRE

    Lindstrom, Kara; Guyer, Amanda E; Mogg, Karin; Bradley, Brendan P.; Fox, Nathan A.; Ernst, Monique; Nelson, Eric E.; Leibenluft, Ellen; Britton, Jennifer C.; Monk, Christopher S.; Pine, Daniel S.; Bar-Haim, Yair

    2009-01-01

    The ability of positive and negative facial signals to influence attention orienting is crucial to social functioning. Given the dramatic developmental change in neural architecture supporting social function, positive and negative facial cues may influence attention orienting differently in relatively young or old individuals. However, virtually no research examines such age-related differences in the neural circuitry supporting attention orienting to emotional faces. We examined age-related...

  19. Pinning cluster synchronization in an array of coupled neural networks under event-based mechanism.

    Science.gov (United States)

    Li, Lulu; Ho, Daniel W C; Cao, Jinde; Lu, Jianquan

    2016-04-01

    Cluster synchronization is a typical collective behavior in coupled dynamical systems, where the synchronization occurs within one group, while there is no synchronization among different groups. In this paper, under event-based mechanism, pinning cluster synchronization in an array of coupled neural networks is studied. A new event-triggered sampled-data transmission strategy, where only local and event-triggering states are utilized to update the broadcasting state of each agent, is proposed to realize cluster synchronization of the coupled neural networks. Furthermore, a self-triggered pinning cluster synchronization algorithm is proposed, and a set of iterative procedures is given to compute the event-triggered time instants. Hence, this will reduce the computational load significantly. Finally, an example is given to demonstrate the effectiveness of the theoretical results. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  20. Separate neural mechanisms underlie choices and strategic preferences in risky decision making.

    Science.gov (United States)

    Venkatraman, Vinod; Payne, John W; Bettman, James R; Luce, Mary Frances; Huettel, Scott A

    2009-05-28

    Adaptive decision making in real-world contexts often relies on strategic simplifications of decision problems. Yet, the neural mechanisms that shape these strategies and their implementation remain largely unknown. Using an economic decision-making task, we dissociate brain regions that predict specific choices from those predicting an individual's preferred strategy. Choices that maximized gains or minimized losses were predicted by functional magnetic resonance imaging activation in ventromedial prefrontal cortex or anterior insula, respectively. However, choices that followed a simplifying strategy (i.e., attending to overall probability of winning) were associated with activation in parietal and lateral prefrontal cortices. Dorsomedial prefrontal cortex, through differential functional connectivity with parietal and insular cortex, predicted individual variability in strategic preferences. Finally, we demonstrate that robust decision strategies follow from neural sensitivity to rewards. We conclude that decision making reflects more than compensatory interaction of choice-related regions; in addition, specific brain systems potentiate choices depending on strategies, traits, and context.

  1. Refractory pediatric cardiogenic shock: A case for mechanical support.

    Science.gov (United States)

    Sachdev, Anil; Mehra, Bharat; Mohanty, Arun; Gupta, Dhiren; Gupta, Neeraj

    2016-11-01

    Acute left ventricular dysfunction in children justifies aggressive treatment because of the high potential for complete recovery. The options for providing mechanical support to the failing heart in a child include extracorporeal membrane oxygenation, left ventricular assist devices, and the use of the intra-aortic balloon pump (IABP). The IABP is a commonly used method of temporary circulatory support in adults. However, despite the availability of pediatric size balloons, the usage of IABP for temporary circulatory support in children has not been widespread. Current case report, first from India in pediatric age group, aims to aware the pediatric intensivist about the role of IABP in providing temporary mechanical cardiovascular support in managing patients with refractory low cardiac output state.

  2. Cross-Language Support Mechanisms Significantly Aid Software Development

    DEFF Research Database (Denmark)

    Pfeiffer, Rolf-Helge; Wasowski, Andrzej

    2012-01-01

    , (2) static checking, (3) navigation, and (4) refactoring of cross-language relations. We investigate whether these four mechanisms indeed improve efficiency and quality of development of multi-language systems. We run a controlled experiment in which 22 participants perform typical software evolution......Contemporary software systems combine many artifacts specified in various modeling and programming languages, domainspecific and general purpose as well. Since multi-language systems are so widespread, working on them calls for tools with cross-language support mechanisms such as (1) visualization...... tasks on the JTrac web application using a prototype tool implementing these mechanisms. The results speak clearly for integration of cross-language support mechanisms into software development tools, and justify research on automatic inference, manipulation and handling of cross-language relations....

  3. Mechanical Circulatory Support for High-Risk Pulmonary Embolism.

    Science.gov (United States)

    Elder, Mahir; Blank, Nimrod; Shemesh, Adi; Pahuja, Mohit; Kaki, Amir; Mohamad, Tamam; Schreiber, Theodore; Giri, Jay

    2018-01-01

    Temporary mechanical circulatory support (MCS) devices have a role in treating high-risk patients with pulmonary embolism with cardiogenic shock. Mechanical circulatory device selection should be made based on center experience and device-specific features. All current devices are effective in decreasing right arterial pressure and providing circulatory support of 4 to 5 L/min. The pulmonary artery pulsatility index may prove to be an unreliable method to assess right ventricular function. Careful clinical evaluation on an individual patient basis should determine the need for MCS. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Physiological mechanisms of sex differences in exertional dyspnoea: role of neural respiratory motor drive.

    Science.gov (United States)

    Schaeffer, Michele R; Mendonca, Cassandra T; Levangie, Marc C; Andersen, Ross E; Taivassalo, Tanja; Jensen, Dennis

    2014-02-01

    What is the central question of this study? Does the combination of a higher neural respiratory drive and greater dynamic mechanical ventilatory constraints during exercise in healthy women versus men form the mechanistic basis of sex differences in activity-related dyspnoea? What is the main finding and its importance? Sex differences in activity-related dyspnoea in health primarily reflected the awareness of a higher neural respiratory drive needed to achieve any given ventilation during exercise in the setting of relatively greater dynamic mechanical ventilatory constraints in women. These findings may have implications for our understanding of the mechanisms of sex differences in exertional dyspnoea in variants of health (e.g. the elderly) and in patients with cardiorespiratory disease. The purpose of this study was to elucidate the physiological mechanisms of sex differences in exertional dyspnoea. We compared detailed measures of neural respiratory motor drive [diaphragmatic EMG (EMGdi) expressed as a percentage of maximal EMGdi (EMGdi%max)], breathing pattern, operating lung volumes, dynamic respiratory mechanics [tidal oesophageal (P(oes,tida)l%peak) and transdiaphragmatic pressure swings (P(di,tidal)%peak) expressed as a percentage of their respective peak values] and sensory intensity and unpleasantness ratings of dyspnoea during symptom-limited incremental cycle exercise in healthy young women (n = 25) and men (n = 25). The tidal volume to forced vital capacity ratio (V(T)%FVC), breathing frequency, EMGdi%max, P(oes,tidal)%peak, P(di,tidal)%peak and sensory intensity and unpleasantness ratings of dyspnoea were higher, while dynamic inspiratory capacity and inspiratory reserve volume were lower at a standardized absolute ventilation of 55 l min(-1) during submaximal exercise in women versus men (all P sex had no demonstrable effect on the inter-relationships between exercise-induced increases in V(T)%FVC, EMGdi%max and sensory intensity and unpleasantness

  5. Refractory pediatric cardiogenic shock: A case for mechanical support

    OpenAIRE

    Anil Sachdev; Bharat Mehra; Arun Mohanty; Dhiren Gupta; Neeraj Gupta

    2016-01-01

    Acute left ventricular dysfunction in children justifies aggressive treatment because of the high potential for complete recovery. The options for providing mechanical support to the failing heart in a child include extracorporeal membrane oxygenation, left ventricular assist devices, and the use of the intra-aortic balloon pump (IABP). The IABP is a commonly used method of temporary circulatory support in adults. However, despite the availability of pediatric size balloons, the usage of IABP...

  6. Support mechanisms for renewables: How risk exposure influences investment incentives

    OpenAIRE

    Kitzing, Lena; Weber, Christoph

    2014-01-01

    We analyse quantitatively how risk exposure from different support mechanisms, such as feed-in tariffs and premiums, can influence the investment incentives for private investors. We develop a net cash flow approach that takes systematic and unsystematic risks into account through cost of capital and the Capital Asset Pricing Model as well as through active liquidity management. Applying the model to a specific case, a German offshore wind park, we find that the support levels required to giv...

  7. Application of neural networks and support vector machine for significant wave height prediction

    Directory of Open Access Journals (Sweden)

    Jadran Berbić

    2017-07-01

    Full Text Available For the purposes of planning and operation of maritime activities, information about wave height dynamics is of great importance. In the paper, real-time prediction of significant wave heights for the following 0.5–5.5 h is provided, using information from 3 or more time points. In the first stage, predictions are made by varying the quantity of significant wave heights from previous time points and various ways of using data are discussed. Afterwards, in the best model, according to the criteria of practicality and accuracy, the influence of wind is taken into account. Predictions are made using two machine learning methods – artificial neural networks (ANN and support vector machine (SVM. The models were built using the built-in functions of software Weka, developed by Waikato University, New Zealand.

  8. A comparative study of support vector machines and artificial neural networks for predicting precipitation in Iran

    Science.gov (United States)

    Hamidi, Omid; Poorolajal, Jalal; Sadeghifar, Majid; Abbasi, Hamed; Maryanaji, Zohreh; Faridi, Hamid Reza; Tapak, Lily

    2015-02-01

    This study compared two machine learning techniques, support vector machines (SVM), and artificial neural network (ANN) in modeling monthly precipitation fluctuations. The SVM and ANN approaches were applied to the monthly precipitation data of two synoptic stations in Hamadan (Airport and Nojeh), the west of Iran. To avoid overfitting, the data were divided into two parts of training (70 %) and test sets (30 %). Then, monthly data from July 1976 to June 2001 and data from April 1961 to November 1996 were considered as training set for the Hamadan and Nojeh stations, respectively, and the remaining were used as test set. The results of the SVM model were compared with those of the ANN based on the root mean square errors, mean absolute errors, determination coefficient, and efficiency coefficient criteria. Based on the comparison, it was found that the SVM model outperformed the ANN, and the estimated precipitation values were in good agreement with the corresponding observed values.

  9. Recurrent neural networks in computer-based clinical decision support for laryngopathies: an experimental study.

    Science.gov (United States)

    Szkoła, Jarosław; Pancerz, Krzysztof; Warchoł, Jan

    2011-01-01

    The main goal of this paper is to give the basis for creating a computer-based clinical decision support (CDS) system for laryngopathies. One of approaches which can be used in the proposed CDS is based on the speech signal analysis using recurrent neural networks (RNNs). RNNs can be used for pattern recognition in time series data due to their ability of memorizing some information from the past. The Elman networks (ENs) are a classical representative of RNNs. To improve learning ability of ENs, we may modify and combine them with another kind of RNNs, namely, with the Jordan networks. The modified Elman-Jordan networks (EJNs) manifest a faster and more exact achievement of the target pattern. Validation experiments were carried out on speech signals of patients from the control group and with two kinds of laryngopathies.

  10. Monthly evaporation forecasting using artificial neural networks and support vector machines

    Science.gov (United States)

    Tezel, Gulay; Buyukyildiz, Meral

    2016-04-01

    Evaporation is one of the most important components of the hydrological cycle, but is relatively difficult to estimate, due to its complexity, as it can be influenced by numerous factors. Estimation of evaporation is important for the design of reservoirs, especially in arid and semi-arid areas. Artificial neural network methods and support vector machines (SVM) are frequently utilized to estimate evaporation and other hydrological variables. In this study, usability of artificial neural networks (ANNs) (multilayer perceptron (MLP) and radial basis function network (RBFN)) and ɛ-support vector regression (SVR) artificial intelligence methods was investigated to estimate monthly pan evaporation. For this aim, temperature, relative humidity, wind speed, and precipitation data for the period 1972 to 2005 from Beysehir meteorology station were used as input variables while pan evaporation values were used as output. The Romanenko and Meyer method was also considered for the comparison. The results were compared with observed class A pan evaporation data. In MLP method, four different training algorithms, gradient descent with momentum and adaptive learning rule backpropagation (GDX), Levenberg-Marquardt (LVM), scaled conjugate gradient (SCG), and resilient backpropagation (RBP), were used. Also, ɛ-SVR model was used as SVR model. The models were designed via 10-fold cross-validation (CV); algorithm performance was assessed via mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R 2). According to the performance criteria, the ANN algorithms and ɛ-SVR had similar results. The ANNs and ɛ-SVR methods were found to perform better than the Romanenko and Meyer methods. Consequently, the best performance using the test data was obtained using SCG(4,2,2,1) with R 2 = 0.905.

  11. Support mechanisms for renewables: How risk exposure influences investment incentives

    Directory of Open Access Journals (Sweden)

    Lena Kitzing

    2016-06-01

    Full Text Available We analyse quantitatively how risk exposure from different support mechanisms, such as feed-in tariffs and premiums, can influence the investment incentives for private investors. We develop a net cash flow approach that takes systematic and unsystematic risks into account through cost of capital and the Capital Asset Pricing Model as well as through active liquidity management. Applying the model to a specific case, a German offshore wind park, we find that the support levels required to give adequate investment incentives are for a feed-in tariff scheme approximately 4-10% lower than for a feed-in premium scheme. The effect of differences in risk exposure from the support schemes is significant and cannot be neglected in policy making, especially when deciding between support instruments or when determining adequate support levels.

  12. Neural evidence supports a dual sensory-motor role for insect wings.

    Science.gov (United States)

    Pratt, Brandon; Deora, Tanvi; Mohren, Thomas; Daniel, Thomas

    2017-09-13

    Flying insects use feedback from various sensory modalities including vision and mechanosensation to navigate through their environment. The rapid speed of mechanosensory information acquisition and processing compensates for the slower processing times associated with vision, particularly under low light conditions. While halteres in dipteran species are well known to provide such information for flight control, less is understood about the mechanosensory roles of their evolutionary antecedent, wings. The features that wing mechanosensory neurons (campaniform sensilla) encode remains relatively unexplored. We hypothesized that the wing campaniform sensilla of the hawkmoth, Manduca sexta, rapidly and selectively extract mechanical stimulus features in a manner similar to halteres. We used electrophysiological and computational techniques to characterize the encoding properties of wing campaniform sensilla. To accomplish this, we developed a novel technique for localizing receptive fields using a focused IR laser that elicits changes in the neural activity of mechanoreceptors. We found that (i) most wing mechanosensors encoded mechanical stimulus features rapidly and precisely, (ii) they are selective for specific stimulus features, and (iii) there is diversity in the encoding properties of wing campaniform sensilla. We found that the encoding properties of wing campaniform sensilla are similar to those for haltere neurons. Therefore, it appears that the neural architecture that underlies the haltere sensory function is present in wings, which lends credence to the notion that wings themselves may serve a similar sensory function. Thus, wings may not only function as the primary actuator of the organism but also as sensors of the inertial dynamics of the animal. © 2017 The Authors.

  13. A mechanism for the inhibition of neural progenitor cell proliferation by cocaine.

    Directory of Open Access Journals (Sweden)

    Chun-Ting Lee

    2008-06-01

    Full Text Available BACKGROUND: Prenatal exposure of the developing brain to cocaine causes morphological and behavioral abnormalities. Recent studies indicate that cocaine-induced proliferation inhibition and/or apoptosis in neural progenitor cells may play a pivotal role in causing these abnormalities. To understand the molecular mechanism through which cocaine inhibits cell proliferation in neural progenitors, we sought to identify the molecules that are responsible for mediating the effect of cocaine on cell cycle regulation. METHODS AND FINDINGS: Microarray analysis followed by quantitative real-time reverse transcription PCR was used to screen cocaine-responsive and cell cycle-related genes in a neural progenitor cell line where cocaine exposure caused a robust anti-proliferative effect by interfering with the G1-to-S transition. Cyclin A2, among genes related to the G1-to-S cell cycle transition, was most strongly down-regulated by cocaine. Down-regulation of cyclin A was also found in cocaine-treated human primary neural and A2B5+ progenitor cells, as well as in rat fetal brains exposed to cocaine in utero. Reversing cyclin A down-regulation by gene transfer counteracted the proliferation inhibition caused by cocaine. Further, we found that cocaine-induced accumulation of reactive oxygen species, which involves N-oxidation of cocaine via cytochrome P450, promotes cyclin A down-regulation by causing an endoplasmic reticulum (ER stress response, as indicated by increased phosphorylation of eIF2alpha and expression of ATF4. In the developing rat brain, the P450 inhibitor cimetidine counteracted cocaine-induced inhibition of neural progenitor cell proliferation as well as down-regulation of cyclin A. CONCLUSIONS: Our results demonstrate that down-regulation of cyclin A underlies cocaine-induced proliferation inhibition in neural progenitors. The down-regulation of cyclin A is initiated by N-oxidative metabolism of cocaine and consequent ER stress. Inhibition of

  14. The European Registry for Patients with Mechanical Circulatory Support (EUROMACS)

    DEFF Research Database (Denmark)

    de By, Theo M M H; Mohacsi, Paul; Gummert, Jan

    2015-01-01

    other founding international members. It aims to promote scientific research to improve care of end-stage heart failure patients with ventricular assist device or a total artificial heart as long-term mechanical circulatory support. Likewise, the organization aims to provide and maintain a registry...

  15. Biological evaluation of mechanical circulatory support systems in calves

    NARCIS (Netherlands)

    Rakhorst, G; VanDerMeer, J; Kik, C; Mihaylov, D; Havlik, P; Trinkl, J; Monties, [No Value

    Data from animal experiments with mechanical circulatory support systems (MCSS) performed in Groningen and Marseille over the past years were used to obtain normal values of hematological, coagulation, rheological and blood chemistry parameters in calves. These parameters were divided between two

  16. Neural mechanisms linking social status and inflammatory responses to social stress

    Science.gov (United States)

    Dedovic, Katarina; Slavich, George M.; Jarcho, Michael R.; Breen, Elizabeth C.; Bower, Julienne E.; Irwin, Michael R.; Eisenberger, Naomi I.

    2016-01-01

    Social stratification has important implications for health and well-being, with individuals lower in standing in a hierarchy experiencing worse outcomes than those higher up the social ladder. Separate lines of past research suggest that alterations in inflammatory processes and neural responses to threat may link lower social status with poorer outcomes. This study was designed to bridge these literatures to investigate the neurocognitive mechanisms linking subjective social status and inflammation. Thirty-one participants reported their subjective social status, and underwent a functional magnetic resonance imaging scan while they were socially evaluated. Participants also provided blood samples before and after the stressor, which were analysed for changes in inflammation. Results showed that lower subjective social status was associated with greater increases in inflammation. Neuroimaging data revealed lower subjective social status was associated with greater neural activity in the dorsomedial prefrontal cortex (DMPFC) in response to negative feedback. Finally, results indicated that activation in the DMPFC in response to negative feedback mediated the relation between social status and increases in inflammatory activity. This study provides the first evidence of a neurocognitive pathway linking subjective social status and inflammation, thus furthering our understanding of how social hierarchies shape neural and physiological responses to social interactions. PMID:26979965

  17. Neural mechanisms linking social status and inflammatory responses to social stress.

    Science.gov (United States)

    Muscatell, Keely A; Dedovic, Katarina; Slavich, George M; Jarcho, Michael R; Breen, Elizabeth C; Bower, Julienne E; Irwin, Michael R; Eisenberger, Naomi I

    2016-06-01

    Social stratification has important implications for health and well-being, with individuals lower in standing in a hierarchy experiencing worse outcomes than those higher up the social ladder. Separate lines of past research suggest that alterations in inflammatory processes and neural responses to threat may link lower social status with poorer outcomes. This study was designed to bridge these literatures to investigate the neurocognitive mechanisms linking subjective social status and inflammation. Thirty-one participants reported their subjective social status, and underwent a functional magnetic resonance imaging scan while they were socially evaluated. Participants also provided blood samples before and after the stressor, which were analysed for changes in inflammation. Results showed that lower subjective social status was associated with greater increases in inflammation. Neuroimaging data revealed lower subjective social status was associated with greater neural activity in the dorsomedial prefrontal cortex (DMPFC) in response to negative feedback. Finally, results indicated that activation in the DMPFC in response to negative feedback mediated the relation between social status and increases in inflammatory activity. This study provides the first evidence of a neurocognitive pathway linking subjective social status and inflammation, thus furthering our understanding of how social hierarchies shape neural and physiological responses to social interactions. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  18. Neural mechanisms underlying sound-induced visual motion perception: An fMRI study.

    Science.gov (United States)

    Hidaka, Souta; Higuchi, Satomi; Teramoto, Wataru; Sugita, Yoichi

    2017-07-01

    Studies of crossmodal interactions in motion perception have reported activation in several brain areas, including those related to motion processing and/or sensory association, in response to multimodal (e.g., visual and auditory) stimuli that were both in motion. Recent studies have demonstrated that sounds can trigger illusory visual apparent motion to static visual stimuli (sound-induced visual motion: SIVM): A visual stimulus blinking at a fixed location is perceived to be moving laterally when an alternating left-right sound is also present. Here, we investigated brain activity related to the perception of SIVM using a 7T functional magnetic resonance imaging technique. Specifically, we focused on the patterns of neural activities in SIVM and visually induced visual apparent motion (VIVM). We observed shared activations in the middle occipital area (V5/hMT), which is thought to be involved in visual motion processing, for SIVM and VIVM. Moreover, as compared to VIVM, SIVM resulted in greater activation in the superior temporal area and dominant functional connectivity between the V5/hMT area and the areas related to auditory and crossmodal motion processing. These findings indicate that similar but partially different neural mechanisms could be involved in auditory-induced and visually-induced motion perception, and neural signals in auditory, visual, and, crossmodal motion processing areas closely and directly interact in the perception of SIVM. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Effects and mechanisms of melatonin on neural differentiation of induced pluripotent stem cells.

    Science.gov (United States)

    Shu, Tao; Wu, Tao; Pang, Mao; Liu, Chang; Wang, Xuan; Wang, Juan; Liu, Bin; Rong, Limin

    2016-06-03

    Melatonin, a lipophilic molecule mainly synthesized in the pineal gland, has properties of antioxidation, anti-inflammation, and antiapoptosis to improve neuroprotective functions. Here, we investigate effects and mechanisms of melatonin on neural differentiation of induced pluripotent stem cells (iPSCs). iPSCs were induced into neural stem cells (NSCs), then further differentiated into neurons in medium with or without melatonin, melatonin receptor antagonist (Luzindole) or Phosphatidylinositide 3 kinase (PI3K) inhibitor (LY294002). Melatonin significantly promoted the number of neurospheres and cell viability. In addition, Melatonin markedly up-regulated gene and protein expression of Nestin and MAP2. However, Luzindole or LY294002 attenuated these increase. The expression of pAKT/AKT were increased by Melatonin, while Luzindole or LY294002 declined these melatonin-induced increase. These results suggest that melatonin significantly increased neural differentiation of iPSCs via activating PI3K/AKT signaling pathway through melatonin receptor. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Common neural substrates support speech and non-speech vocal tract gestures.

    Science.gov (United States)

    Chang, Soo-Eun; Kenney, Mary Kay; Loucks, Torrey M J; Poletto, Christopher J; Ludlow, Christy L

    2009-08-01

    The issue of whether speech is supported by the same neural substrates as non-speech vocal tract gestures has been contentious. In this fMRI study we tested whether producing non-speech vocal tract gestures in humans shares the same functional neuroanatomy as non-sense speech syllables. Production of non-speech vocal tract gestures, devoid of phonological content but similar to speech in that they had familiar acoustic and somatosensory targets, was compared to the production of speech syllables without meaning. Brain activation related to overt production was captured with BOLD fMRI using a sparse sampling design for both conditions. Speech and non-speech were compared using voxel-wise whole brain analyses, and ROI analyses focused on frontal and temporoparietal structures previously reported to support speech production. Results showed substantial activation overlap between speech and non-speech function in regions. Although non-speech gesture production showed greater extent and amplitude of activation in the regions examined, both speech and non-speech showed comparable left laterality in activation for both target perception and production. These findings posit a more general role of the previously proposed "auditory dorsal stream" in the left hemisphere--to support the production of vocal tract gestures that are not limited to speech processing.

  1. An adaptive neural mechanism for acoustic motion perception with varying sparsity

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    .e. extracting information about its direction and velocity. Here we focus on auditory motion perception of sound stimuli, which is poorly understood as compared to its visual counterpart. In earlier work we have developed a bio-inspired neural learning mechanism for acoustic motion perception. The mechanism...... extracts directional information via a model of the peripheral auditory system of lizards. The mechanism uses only this directional information obtained via specific motor behaviour to learn the angular velocity of unoccluded sound stimuli in motion. In nature however the stimulus being tracked may...... be occluded by artefacts in the environment, such as an escaping prey momentarily disappearing behind a cover of trees. This article extends the earlier work by presenting a comparative investigation of auditory motion perception for unoccluded and occluded tonal sound stimuli with a frequency of 2.2 k...

  2. An "as soon as possible" effect in human intertemporal decision making: behavioral evidence and neural mechanisms.

    Science.gov (United States)

    Kable, Joseph W; Glimcher, Paul W

    2010-05-01

    Many decisions involve a trade-off between the quality of an outcome and the time at which that outcome is received. In psychology and behavioral economics, the most widely studied models hypothesize that the values of future gains decline as a roughly hyperbolic function of delay from the present. Recently, it has been proposed that this hyperbolic-like decline in value arises from the interaction of two separate neural systems: one specialized to value immediate rewards and the other specialized to value delayed rewards. Here we report behavioral and functional magnetic resonance imaging results that are inconsistent with both the standard behavioral models of discounting and the hypothesis that separate neural systems value immediate and delayed rewards. Behaviorally, we find that human subjects do not necessarily make the impulsive preference reversals predicted by hyperbolic-like discounting. We also find that blood oxygenation level dependent activity in ventral striatum, medial prefrontal, and posterior cingulate cortex does not track whether an immediate reward was present, as proposed by the separate neural systems hypothesis. Activity in these regions was correlated with the subjective value of both immediate and delayed rewards. Rather than encoding only the relative value of one reward compared with another, these values are represented on a more absolute scale. These data support an alternative behavioral-neural model (which we call "ASAP"), in which subjective value declines hyperbolically relative to the soonest currently available reward and a small number of valuation areas serve as a final common pathway through which these subjective values guide choice.

  3. Neurobiology of pair bonding in fishes; convergence of neural mechanisms across distant vertebrate lineages

    KAUST Repository

    Nowicki, Jessica

    2017-11-14

    Pair bonding has independently evolved numerous times among vertebrates. The governing neural mechanisms of pair bonding have only been studied in depth in the mammalian model species, the prairie vole, Microtus ochrogaster. In this species, oxytocin (OT), arginine vasopressin (AVP), dopamine (DA), and opioid (OP) systems play key roles in signaling in the formation and maintenance of pair bonding by targeting specific social and reward-mediating brain regions. By contrast, the neural basis of pair bonding is poorly studied in other vertebrates, and especially those of early origins, limiting our understanding of the evolutionary history of pair bonding regulatory mechanisms. We compared receptor gene expression between pair bonded and solitary individuals across eight socio-functional brain regions. We found that in females, ITR and V1aR receptor expression varied in the lateral septum-like region (the Vv/Vl), while in both sexes D1R, D2R, and MOR expression varied within the mesolimbic reward system, including a striatum-like region (the Vc); mirroring sites of action in M. ochrogaster. This study provides novel insights into the neurobiology of teleost pair bonding. It also reveals high convergence in the neurochemical mechanisms governing pair bonding across actinopterygians and sarcopterygians, by repeatedly co-opting and similarly assembling deep neurochemical and neuroanatomical homologies that originated in ancestral osteithes.

  4. On the Control of Social Approach-Avoidance Behavior: Neural and Endocrine Mechanisms.

    Science.gov (United States)

    Kaldewaij, Reinoud; Koch, Saskia B J; Volman, Inge; Toni, Ivan; Roelofs, Karin

    The ability to control our automatic action tendencies is crucial for adequate social interactions. Emotional events trigger automatic approach and avoidance tendencies. Although these actions may be generally adaptive, the capacity to override these emotional reactions may be key to flexible behavior during social interaction. The present chapter provides a review of the neuroendocrine mechanisms underlying this ability and their relation to social psychopathologies. Aberrant social behavior, such as observed in social anxiety or psychopathy, is marked by abnormalities in approach-avoidance tendencies and the ability to control them. Key neural regions involved in the regulation of approach-avoidance behavior are the amygdala, widely implicated in automatic emotional processing, and the anterior prefrontal cortex, which exerts control over the amygdala. Hormones, especially testosterone and cortisol, have been shown to affect approach-avoidance behavior and the associated neural mechanisms. The present chapter also discusses ways to directly influence social approach and avoidance behavior and will end with a research agenda to further advance this important research field. Control over approach-avoidance tendencies may serve as an exemplar of emotional action regulation and might have a great value in understanding the underlying mechanisms of the development of affective disorders.

  5. An Integrative Model for the Neural Mechanism of Eye Movement Desensitization and Reprocessing (EMDR).

    Science.gov (United States)

    Coubard, Olivier A

    2016-01-01

    Since the seminal report by Shapiro that bilateral stimulation induces cognitive and emotional changes, 26 years of basic and clinical research have examined the effects of Eye Movement Desensitization and Reprocessing (EMDR) in anxiety disorders, particularly in post-traumatic stress disorder (PTSD). The present article aims at better understanding EMDR neural mechanism. I first review procedural aspects of EMDR protocol and theoretical hypothesis about EMDR effects, and develop the reasons why the scientific community is still divided about EMDR. I then slide from psychology to physiology describing eye movements/emotion interaction from the physiological viewpoint, and introduce theoretical and technical tools used in movement research to re-examine EMDR neural mechanism. Using a recent physiological model for the neuropsychological architecture of motor and cognitive control, the Threshold Interval Modulation with Early Release-Rate of rIse Deviation with Early Release (TIMER-RIDER)-model, I explore how attentional control and bilateral stimulation may participate to EMDR effects. These effects may be obtained by two processes acting in parallel: (i) activity level enhancement of attentional control component; and (ii) bilateral stimulation in any sensorimotor modality, both resulting in lower inhibition enabling dysfunctional information to be processed and anxiety to be reduced. The TIMER-RIDER model offers quantitative predictions about EMDR effects for future research about its underlying physiological mechanisms.

  6. An integrative model for the neural mechanism of Eye Movement Desensitization and Reprocessing (EMDR

    Directory of Open Access Journals (Sweden)

    Olivier A. Coubard

    2016-04-01

    Full Text Available Since the seminal report by Shapiro that bilateral stimulation induces cognitive and emotional changes, twenty-six years of basic and clinical research have examined the effects of Eye Movement Desensitization and Reprocessing (EMDR in anxiety disorders, particularly in Post-Traumatic Stress Disorder (PTSD. The present article aims at better understanding EMDR neural mechanism. I first review procedural aspects of EMDR protocol and theoretical hypothesis about EMDR effects, and develop the reasons why the scientific community is still divided about EMDR. I then slide from psychology to physiology describing eye movements/emotion interaction from the physiological viewpoint, and introduce theoretical and technical tools used in movement research to re-examine EMDR neural mechanism. Using a recent physiological model for the neuropsychological architecture of motor and cognitive control, the Threshold Interval Modulation with Early Release-Rate of rIse Deviation with Early Release – TIMER-RIDER – model, I explore how attentional control and bilateral stimulation may participate to EMDR effects. These effects may be obtained by two processes acting in parallel: (i activity level enhancement of attentional control component; and (ii bilateral stimulation in any sensorimotor modality, both resulting in lower inhibition enabling dysfunctional information to be processed and anxiety to be reduced. The TIMER-RIDER model offers quantitative predictions about EMDR effects for future research about its underlying physiological mechanisms.

  7. A Spiking Neural Network Based Cortex-Like Mechanism and Application to Facial Expression Recognition

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    Si-Yao Fu

    2012-01-01

    Full Text Available In this paper, we present a quantitative, highly structured cortex-simulated model, which can be simply described as feedforward, hierarchical simulation of ventral stream of visual cortex using biologically plausible, computationally convenient spiking neural network system. The motivation comes directly from recent pioneering works on detailed functional decomposition analysis of the feedforward pathway of the ventral stream of visual cortex and developments on artificial spiking neural networks (SNNs. By combining the logical structure of the cortical hierarchy and computing power of the spiking neuron model, a practical framework has been presented. As a proof of principle, we demonstrate our system on several facial expression recognition tasks. The proposed cortical-like feedforward hierarchy framework has the merit of capability of dealing with complicated pattern recognition problems, suggesting that, by combining the cognitive models with modern neurocomputational approaches, the neurosystematic approach to the study of cortex-like mechanism has the potential to extend our knowledge of brain mechanisms underlying the cognitive analysis and to advance theoretical models of how we recognize face or, more specifically, perceive other people’s facial expression in a rich, dynamic, and complex environment, providing a new starting point for improved models of visual cortex-like mechanism.

  8. Implicit sequence learning in juvenile anorexia nervosa: neural mechanisms and the impact of starvation.

    Science.gov (United States)

    Firk, Christine; Mainz, Verena; Schulte-Ruether, Martin; Fink, Gereon; Herpertz-Dahlmann, Beate; Konrad, Kerstin

    2015-11-01

    Previous studies have reported that cognitive deficits occur in patients with anorexia nervosa (AN) and that these deficits may represent a predisposition towards developing AN or perpetuate the disorder. Specifically, dysfunctional implicit learning may contribute to the development of highly resistant dieting behaviours that are fundamental to the persistence of the disorder. Thus, the aims of this study were (a) to investigate implicit sequence learning in adolescent patients with AN before and after weight recovery and (b) to elucidate the associated neural mechanisms in acute AN relative to healthy controls. In a behavioural study, implicit sequence learning was assessed using a serial reaction time task in 27 adolescents with AN before (T1) and after weight recovery (T2) compared with age-matched healthy controls (HC) who were assessed at similar time intervals. The neural correlates of implicit sequence learning were subsequently investigated in 19 AN patients shortly after they were admitted to the hospital and 20 HC using functional magnetic resonance imaging (fMRI). At T1, AN patients showed reduced sequence learning compared with HC. However, no behavioural differences between HC and AN patients were found at T2. At the neural level, acute AN patients showed reduced thalamic activation during sequence learning compared with HC subjects. Our data suggest that the impaired implicit learning observed in adolescent AN patients before weight gain is a state-related dysfunction that normalises with weight gain. Thus, implicit learning deficits do not appear to represent a predisposition towards developing AN; rather, these deficits should be considered when planning psychotherapeutic interventions for acute AN. Reduced thalamic activation during the acute stage of AN may indicate a starvation-induced dysfunction of the neural circuitry that is involved in behavioural flexibility. © 2015 Association for Child and Adolescent Mental Health.

  9. Neural mechanisms underlying the cost of task switching: an ERP study.

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    Ling Li

    Full Text Available BACKGROUND: When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC. Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. METHODOLOGY/PRINCIPAL FINDINGS: An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI and cue-stimulus interval (CSI were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP, and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC and posterior parietal cortex (PPC. CONCLUSIONS/SIGNIFICANCE: The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set.

  10. Neural Mechanisms of the Influence of Popularity on Adolescent Ratings of Music

    OpenAIRE

    Berns, Gregory S.; Capra, C. Monica; Moore, Sara; Noussair, Charles

    2009-01-01

    It is well-known that social influences affect consumption decisions. We used functional magnetic resonance imaging (fMRI) to elucidate the neural mechanisms associated with social influence with regard to a common consumer good: music. Our study population was adolescents, age 12–17. Music is a common purchase in this age group, and it is widely believed that adolescent behavior is influenced by perceptions of popularity in their reference group. Using 15-second clips of songs from MySpace.c...

  11. Increased diaphragmatic contribution to inspiratory effort during neurally adjusted ventilatory assistance versus pressure support: an electromyographic study.

    Science.gov (United States)

    Cecchini, Jérôme; Schmidt, Matthieu; Demoule, Alexandre; Similowski, Thomas

    2014-11-01

    Neurally adjusted ventilatory assist (NAVA), regulated exclusively by the electromyographic activity (EA) of the diaphragm (EAdi), could affect the distribution of neural drive to the various inspiratory muscles. The objective of this study was to compare EAdi, EA of the scalene (EAscal), and EA of the alae nasi (EAan), according to the ventilatory mode and assist level in 12 mechanically ventilated patients. Seven assist levels of pressure support ventilation (PSV) and NAVA were sequentially applied. EAdi, EAscal, and EAan were quantified and expressed as a percentage of their maximum values. The relative contributions of extradiaphragmatic muscles to inspiratory efforts were assessed by calculating EAscal/EAdi and EAan/EAdi ratios. Three assist levels for each of the two ventilatory modes that resulted in EAdi values of 80 to 100%, 60 to 80%, and 40 to 60% were assigned to three groups (N1, N2, and N3). Results are expressed as median and interquartile range. EA of inspiratory muscles decreased during PSV and NAVA (P PSV in N1 and N3 (65% [62 to 64] and 27% [18 to 34] in NAVA vs. 90% [81 to 100] and 49% [40 to 55] in PSV, P = 0.007). Altogether, EAscal/EAdi and EAan/EAdi ratios were lower in NAVA than PSV (0.7 [0.6 to 0.7] and 0.7 [0.6 to 0.8] in NAVA vs. 0.9 [0.8 to 1.1] and 0.9 [0.7 to 1.1] in PSV, P PSV both reduced extradiaphragmatic inspiratory muscle activity, in proportion to the level of assistance. Compared with PSV, NAVA resulted in a predominant contribution of the diaphragm to inspiratory effort.

  12. Support vector machine based training of multilayer feedforward neural networks as optimized by particle swarm algorithm: application in QSAR studies of bioactivity of organic compounds.

    Science.gov (United States)

    Lin, Wei-Qi; Jiang, Jian-Hui; Zhou, Yan-Ping; Wu, Hai-Long; Shen, Guo-Li; Yu, Ru-Qin

    2007-01-30

    Multilayer feedforward neural networks (MLFNNs) are important modeling techniques widely used in QSAR studies for their ability to represent nonlinear relationships between descriptors and activity. However, the problems of overfitting and premature convergence to local optima still pose great challenges in the practice of MLFNNs. To circumvent these problems, a support vector machine (SVM) based training algorithm for MLFNNs has been developed with the incorporation of particle swarm optimization (PSO). The introduction of the SVM based training mechanism imparts the developed algorithm with inherent capacity for combating the overfitting problem. Moreover, with the implementation of PSO for searching the optimal network weights, the SVM based learning algorithm shows relatively high efficiency in converging to the optima. The proposed algorithm has been evaluated using the Hansch data set. Application to QSAR studies of the activity of COX-2 inhibitors is also demonstrated. The results reveal that this technique provides superior performance to backpropagation (BP) and PSO training neural networks.

  13. Brain Mechanisms Supporting Modulation of Pain by Mindfulness Meditation

    Science.gov (United States)

    Zeidan, F.; Martucci, K.T.; Kraft, R.A.; Gordon, N.S.; McHaffie, J.G.; Coghill, R.C.

    2011-01-01

    The subjective experience of one’s environment is constructed by interactions among sensory, cognitive, and affective processes. For centuries, meditation has been thought to influence such processes by enabling a non-evaluative representation of sensory events. To better understand how meditation influences the sensory experience, we employed arterial spin labeling (ASL) functional magnetic resonance imaging to assess the neural mechanisms by which mindfulness meditation influences pain in healthy human participants. After four-days of mindfulness meditation training, meditating in the presence of noxious stimulation significantly reduced pain-unpleasantness by 57% and pain-intensity ratings by 40% when compared to rest. A two factor repeated measures analysis of variance was used to identify interactions between meditation and pain-related brain activation. Meditation reduced pain-related activation of the contra lateral primary somatosensory cortex. Multiple regression analysis was used to identify brain regions associated with individual differences in the magnitude of meditation-related pain reductions. Meditation-induced reductions in pain intensity ratings were associated with increased activity in the anterior cingulate cortex and anterior insula, areas involved in the cognitive regulation of nociceptive processing. Reductions in pain unpleasantness ratings were associated with orbitofrontal cortex activation, an area implicated in reframing the contextual evaluation of sensory events. Moreover, reductions in pain unpleasantness also were associated with thalamic deactivation, which may reflect a limbic gating mechanism involved in modifying interactions between afferent in put and executive-order brain areas. Taken together, these data indicate that meditation engages multiple brain mechanisms that alter the construction of the subjectively available pain experience from afferent information. PMID:21471390

  14. Performance Evaluation of the Machine Learning Algorithms Used in Inference Mechanism of a Medical Decision Support System

    Directory of Open Access Journals (Sweden)

    Mert Bal

    2014-01-01

    Full Text Available The importance of the decision support systems is increasingly supporting the decision making process in cases of uncertainty and the lack of information and they are widely used in various fields like engineering, finance, medicine, and so forth, Medical decision support systems help the healthcare personnel to select optimal method during the treatment of the patients. Decision support systems are intelligent software systems that support decision makers on their decisions. The design of decision support systems consists of four main subjects called inference mechanism, knowledge-base, explanation module, and active memory. Inference mechanism constitutes the basis of decision support systems. There are various methods that can be used in these mechanisms approaches. Some of these methods are decision trees, artificial neural networks, statistical methods, rule-based methods, and so forth. In decision support systems, those methods can be used separately or a hybrid system, and also combination of those methods. In this study, synthetic data with 10, 100, 1000, and 2000 records have been produced to reflect the probabilities on the ALARM network. The accuracy of 11 machine learning methods for the inference mechanism of medical decision support system is compared on various data sets.

  15. Performance evaluation of the machine learning algorithms used in inference mechanism of a medical decision support system.

    Science.gov (United States)

    Bal, Mert; Amasyali, M Fatih; Sever, Hayri; Kose, Guven; Demirhan, Ayse

    2014-01-01

    The importance of the decision support systems is increasingly supporting the decision making process in cases of uncertainty and the lack of information and they are widely used in various fields like engineering, finance, medicine, and so forth, Medical decision support systems help the healthcare personnel to select optimal method during the treatment of the patients. Decision support systems are intelligent software systems that support decision makers on their decisions. The design of decision support systems consists of four main subjects called inference mechanism, knowledge-base, explanation module, and active memory. Inference mechanism constitutes the basis of decision support systems. There are various methods that can be used in these mechanisms approaches. Some of these methods are decision trees, artificial neural networks, statistical methods, rule-based methods, and so forth. In decision support systems, those methods can be used separately or a hybrid system, and also combination of those methods. In this study, synthetic data with 10, 100, 1000, and 2000 records have been produced to reflect the probabilities on the ALARM network. The accuracy of 11 machine learning methods for the inference mechanism of medical decision support system is compared on various data sets.

  16. Curriculum Assessment Using Artificial Neural Network and Support Vector Machine Modeling Approaches: A Case Study. IR Applications. Volume 29

    Science.gov (United States)

    Chen, Chau-Kuang

    2010-01-01

    Artificial Neural Network (ANN) and Support Vector Machine (SVM) approaches have been on the cutting edge of science and technology for pattern recognition and data classification. In the ANN model, classification accuracy can be achieved by using the feed-forward of inputs, back-propagation of errors, and the adjustment of connection weights. In…

  17. A Neural Mechanism for Background Information-Gated Learning Based on Axonal-Dendritic Overlaps

    Science.gov (United States)

    Mainetti, Matteo; Ascoli, Giorgio A.

    2015-01-01

    Experiencing certain events triggers the acquisition of new memories. Although necessary, however, actual experience is not sufficient for memory formation. One-trial learning is also gated by knowledge of appropriate background information to make sense of the experienced occurrence. Strong neurobiological evidence suggests that long-term memory storage involves formation of new synapses. On the short time scale, this form of structural plasticity requires that the axon of the pre-synaptic neuron be physically proximal to the dendrite of the post-synaptic neuron. We surmise that such “axonal-dendritic overlap” (ADO) constitutes the neural correlate of background information-gated (BIG) learning. The hypothesis is based on a fundamental neuroanatomical constraint: an axon must pass close to the dendrites that are near other neurons it contacts. The topographic organization of the mammalian cortex ensures that nearby neurons encode related information. Using neural network simulations, we demonstrate that ADO is a suitable mechanism for BIG learning. We model knowledge as associations between terms, concepts or indivisible units of thought via directed graphs. The simplest instantiation encodes each concept by single neurons. Results are then generalized to cell assemblies. The proposed mechanism results in learning real associations better than spurious co-occurrences, providing definitive cognitive advantages. PMID:25767887

  18. Handedness is related to neural mechanisms underlying hemispheric lateralization of face processing

    Science.gov (United States)

    Frässle, Stefan; Krach, Sören; Paulus, Frieder Michel; Jansen, Andreas

    2016-06-01

    While the right-hemispheric lateralization of the face perception network is well established, recent evidence suggests that handedness affects the cerebral lateralization of face processing at the hierarchical level of the fusiform face area (FFA). However, the neural mechanisms underlying differential hemispheric lateralization of face perception in right- and left-handers are largely unknown. Using dynamic causal modeling (DCM) for fMRI, we aimed to unravel the putative processes that mediate handedness-related differences by investigating the effective connectivity in the bilateral core face perception network. Our results reveal an enhanced recruitment of the left FFA in left-handers compared to right-handers, as evidenced by more pronounced face-specific modulatory influences on both intra- and interhemispheric connections. As structural and physiological correlates of handedness-related differences in face processing, right- and left-handers varied with regard to their gray matter volume in the left fusiform gyrus and their pupil responses to face stimuli. Overall, these results describe how handedness is related to the lateralization of the core face perception network, and point to different neural mechanisms underlying face processing in right- and left-handers. In a wider context, this demonstrates the entanglement of structurally and functionally remote brain networks, suggesting a broader underlying process regulating brain lateralization.

  19. Neural mechanisms of eye contact when listening to another person talking.

    Science.gov (United States)

    Jiang, Jing; Borowiak, Kamila; Tudge, Luke; Otto, Carolin; von Kriegstein, Katharina

    2017-02-01

    Eye contact occurs frequently and voluntarily during face-to-face verbal communication. However, the neural mechanisms underlying eye contact when it is accompanied by spoken language remain unexplored to date. Here we used a novel approach, fixation-based event-related functional magnetic resonance imaging (fMRI), to simulate the listener making eye contact with a speaker during verbal communication. Participants' eye movements and fMRI data were recorded simultaneously while they were freely viewing a pre-recorded speaker talking. The eye tracking data were then used to define events for the fMRI analyses. The results showed that eye contact in contrast to mouth fixation involved visual cortical areas (cuneus, calcarine sulcus), brain regions related to theory of mind/intentionality processing (temporoparietal junction, posterior superior temporal sulcus, medial prefrontal cortex) and the dorsolateral prefrontal cortex. In addition, increased effective connectivity was found between these regions for eye contact in contrast to mouth fixations. The results provide first evidence for neural mechanisms underlying eye contact when watching and listening to another person talking. The network we found might be well suited for processing the intentions of communication partners during eye contact in verbal communication. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  20. Neural mechanisms controlling seasonal reproduction: principles derived from the sheep model and its comparison with hamsters.

    Science.gov (United States)

    Weems, Peyton W; Goodman, Robert L; Lehman, Michael N

    2015-04-01

    Seasonal reproduction is a common adaptive strategy among mammals that allows for breeding to occur at times of the year when it is most advantageous for the subsequent survival and growth of offspring. A major mechanism responsible for seasonal reproduction is a striking increase in the responsiveness of gonadotropin-releasing hormone (GnRH) neurons to the negative feedback effects of estradiol. The neural and neuroendocrine circuitry responsible for mammalian seasonal reproduction has been primarily studied in three animal models: the sheep, and two species of hamsters. In this review, we first describe the afferent signals, neural circuitry and transmitters/peptides responsible for seasonal reproductive transitions in sheep, and then compare these mechanisms with those derived from studies in hamsters. The results suggest common principles as well as differences in the role of specific brain nuclei and neuropeptides, including that of kisspeptin cells of the hypothalamic arcuate nucleus, in regulating seasonal reproduction among mammals. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Fetal Alcohol Spectrum Disorder (FASD Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets

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    James A. Marrs

    2013-06-01

    Full Text Available Fetal alcohol spectrum disorder (FASD, caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection.

  2. Hormonal and neural mechanisms of food reward, eating behaviour and obesity.

    Science.gov (United States)

    Murray, Susan; Tulloch, Alastair; Gold, Mark S; Avena, Nicole M

    2014-09-01

    With rising rates of obesity, research continues to explore the contributions of homeostatic and hedonic mechanisms related to eating behaviour. In this Review, we synthesize the existing information on select biological mechanisms associated with reward-related food intake, dealing primarily with consumption of highly palatable foods. In addition to their established functions in normal feeding, three primary peripheral hormones (leptin, ghrelin and insulin) play important parts in food reward. Studies in laboratory animals and humans also show relationships between hyperphagia or obesity and neural pathways involved in reward. These findings have prompted questions regarding the possibility of addictive-like aspects in food consumption. Further exploration of this topic may help to explain aberrant eating patterns, such as binge eating, and provide insight into the current rates of overweight and obesity.

  3. Development of a Pediatric Cardiac Mechanical Support Program.

    Science.gov (United States)

    Kashyap, Abhishek; Turek, Joseph W; Wagner, Samantha J; Felderman, Laura; Jaggers, Elizabeth A; Gruber, Peter J; Edens, R Erik

    2017-11-03

    The development of a pediatric cardiac support program is a complex, multidisciplinary project. This study describes the University of Iowa Congenital Heart Program's experience from its inception to the present. In, we examine those specific factors that have led to substantial improvements in the program, additionally identifying where further gains can be made. We retrospectively reviewed all pediatric patients who received mechanical cardiac support at the University of Iowa from the inception of the program in 1991. In total, 29 patients received mechanical support between December 1991 and December 2015 and are included in the study. Twelve patients received continuous flow devices and 17 patients received pulsatile flow devices. Median age at implant was 12.8 years (range 0.1-18.2 years). Median weight at implant was 40.5 kg (3.2-123.4 kg). Factors examined included: operating room (OR) time, intensive care unit and hospital length of stay, intubation days, blood product usage, pre- and post-operative bilirubin, creatinine, natriuretic peptide B (NPPB), and device implanted. Categorical and continuous variables were compared using Chi-squared and Wilcoxon rank-sum tests, respectively. Of the 29 patients who received mechanical support, 17 (58.6%) were discharged home, 11 (37.9%) died during their hospitalization, and 1 (3.5%) remains hospitalized. Median length of ventricular assist device support was 59.5 days (range 1-653 days). Between December 1991 and December 2011, in-hospital mortality was 64.3%. Following this period, significant changes were made to patient management with in-hospital mortality decreasing to 13.3% between February 2013 and December 2015. Comparison between deceased and living patients revealed several significant factors including: median number of packed red blood cells transfused, 8 versus 4 units (P = 0.048), median OR time, 396 versus 299 min (P = 0.003), and device implanted. During the early stages of the mechanical

  4. Age-related changes in neural oscillations supporting context memory retrieval.

    Science.gov (United States)

    Strunk, Jonathan; James, Taylor; Arndt, Jason; Duarte, Audrey

    2017-06-01

    Recent evidence suggests that directing attention toward single item-context associations during encoding improves young and older adults' context memory performance and reduces demands on executive functions during retrieval. In everyday situations, there are many event features competing for our attention, and our ability to successfully recover those details may depend on our ability to ignore others. Failures of selective attention may contribute to older adults' context memory impairments. In the current electroencephalogram (EEG) study, we assessed the effects of age on processes supporting successful context memory retrieval of selectively attended features as indexed by neural oscillations. During encoding, young and older adults were directed to attend to a picture of an object and its relationship to one of two concurrently presented contextual details: a color or scene. At retrieval, we tested their memory for the object, its attended and unattended context features, and their confidence for both the attended and unattended features. Both groups showed greater memory for attended than unattended contextual features. However, older adults showed evidence of hyper-binding between attended and unattended context features while the young adults did not. EEG results in the theta band suggest that young and older adults recollect similar amounts of information but brain-behavior correlations suggest that this information was supportive of contextual memory performance, particularly for young adults. By contrast, sustained beta desynchronization, indicative of sensory reactivation and episodic reconstruction, was correlated with contextual memory performance for older adults only. We conclude that older adults' inhibition deficits during encoding reduced the selectivity of their contextual memories, which led to reliance on executive functions like episodic reconstruction to support successful memory retrieval. Copyright © 2017 Elsevier Ltd. All rights

  5. Mindfulness training applied to addiction therapy: insights into the neural mechanisms of positive behavioral change

    Directory of Open Access Journals (Sweden)

    Garl

    2016-07-01

    Full Text Available Eric L Garland,1,2 Matthew O Howard,3 Sarah E Priddy,1 Patrick A McConnell,4 Michael R Riquino,1 Brett Froeliger4 1College of Social Work, 2Hunstsman Cancer Institute, University of Utah, Salt Lake City, UT, USA; 3School of Social Work, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 4Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA Abstract: Dual-process models from neuroscience suggest that addiction is driven by dysregulated interactions between bottom-up neural processes underpinning reward learning and top-down neural functions subserving executive function. Over time, drug use causes atrophy in prefrontally mediated cognitive control networks and hijacks striatal circuits devoted to processing natural rewards in service of compulsive seeking of drug-related reward. In essence, mindfulness-based interventions (MBIs can be conceptualized as mental training programs for exercising, strengthening, and remediating these functional brain networks. This review describes how MBIs may remediate addiction by regulating frontostriatal circuits, thereby restoring an adaptive balance between these top-down and bottom-up processes. Empirical evidence is presented suggesting that MBIs facilitate cognitive control over drug-related automaticity, attentional bias, and drug cue reactivity, while enhancing responsiveness to natural rewards. Findings from the literature are incorporated into an integrative account of the neural mechanisms of mindfulness-based therapies for effecting positive behavior change in the context of addiction recovery. Implications of our theoretical framework are presented with respect to how these insights can inform the addiction therapy process. Keywords: mindfulness, frontostriatal, savoring, cue reactivity, hedonic dysregulation, reward, addiction

  6. Error awareness and salience processing in the oddball task: Shared neural mechanisms.

    Directory of Open Access Journals (Sweden)

    Helga A Harsay

    2012-08-01

    Full Text Available A body of work suggests that there are similarities in the way we become aware of an error and process motivationally salient events. Yet, evidence for a shared neural mechanism has not been provided. A within-subject investigation of the brain regions involved in error awareness and salience processing has not been reported. While the neural response to motivationally salient events is classically studied during target detection after longer target-to-target intervals in an oddball task and engages a widespread insula-thalamo-cortical brain network, error awareness has recently been linked to, most prominently, anterior insula cortex. Here we explore whether the anterior insula activation for error awareness is related to salience processing, by testing for activation overlap in subjects undergoing two different task settings. Using a within-subjects design, we show activation overlap in six major brain areas during aware errors in an antisaccade task and during target detection (which were associated with longer target-to-target interval conditions in an oddball task: anterior insula, anterior cingulate, supplementary motor area, thalamus, brainstem and parietal lobe. Within subject analyses shows that the insula is engaged in both error awareness and the processing of salience, and that the anterior insula is more involved in both processes than the posterior insula. The results of a fine-grained spatial pattern overlap analysis between active clusters in the same subjects indicated that even if the anterior insula is activated for both error awareness and salience processing, the two types of processes might tend to activate non-identical neural ensembles on a finer-grained spatial level. Together, these outcomes suggest a similar functional phenomenon in the two different task settings. Error awareness and salience processing share a functional anatomy, with a tendency towards subregional dorsal and ventral specialization within the

  7. Error awareness and salience processing in the oddball task: shared neural mechanisms.

    Science.gov (United States)

    Harsay, Helga A; Spaan, Marcus; Wijnen, Jasper G; Ridderinkhof, K Richard

    2012-01-01

    A body of work suggests similarities in the way we become aware of an error and process motivationally salient events. Yet, evidence for a shared neural mechanism has not been provided. A within subject investigation of the brain regions involved in error awareness and salience processing has not been reported. While the neural response to motivationally salient events is classically studied during target detection after longer target-to-target intervals in an oddball task and engages a widespread insula-thalamo-cortical brain network, error awareness has recently been linked to, most prominently, anterior insula cortex. Here we explore whether the anterior insula activation for error awareness is related to salience processing, by testing for activation overlap in subjects undergoing two different task settings. Using a within subjects design, we show activation overlap in six major brain areas during aware errors in an antisaccade task and during target detection after longer target-to-target intervals in an oddball task: anterior insula, anterior cingulate, supplementary motor area, thalamus, brainstem, and parietal lobe. Within subject analyses shows that the insula is engaged in both error awareness and the processing of salience, and that the anterior insula is more involved in both processes than the posterior insula. The results of a fine-grained spatial pattern overlap analysis between active clusters in the same subjects indicates that even if the anterior insula is activated for both error awareness and salience processing, the two types of processes might tend to activate non-identical neural ensembles on a finer-grained spatial level. Together, these outcomes suggest a similar functional phenomenon in the two different task settings. Error awareness and salience processing share a functional anatomy, with a tendency toward subregional dorsal and ventral specialization within the anterior insula.

  8. Mindfulness Meditation-Based Pain Relief Employs Different Neural Mechanisms Than Placebo and Sham Mindfulness Meditation-Induced Analgesia

    Science.gov (United States)

    Emerson, Nichole M.; Farris, Suzan R.; Ray, Jenna N.; Jung, Youngkyoo; McHaffie, John G.; Coghill, Robert C.

    2015-01-01

    STATEMENT Recent findings have demonstrated that mindfulness meditation significantly reduces pain. Given that the “gold standard” for evaluating the efficacy of behavioral interventions is based on appropriate placebo comparisons, it is imperative that we establish whether there is an effect supporting meditation-related pain relief above and beyond the effects of placebo. Here, we provide novel evidence demonstrating that mindfulness meditation produces greater pain relief and employs distinct neural mechanisms than placebo cream and sham mindfulness meditation. Specifically, mindfulness meditation-induced pain relief activated higher-order brain regions, including the orbitofrontal and cingulate cortices. In contrast, placebo analgesia was associated with decreased pain-related brain activation. These findings demonstrate that mindfulness meditation reduces pain through unique mechanisms and may foster greater acceptance of meditation as an adjunct pain therapy. PMID:26586819

  9. Dual origins of measured phase-amplitude coupling reveal distinct neural mechanisms underlying episodic memory in the human cortex.

    Science.gov (United States)

    Vaz, Alex P; Yaffe, Robert B; Wittig, John H; Inati, Sara K; Zaghloul, Kareem A

    2017-03-01

    Phase-amplitude coupling (PAC) is hypothesized to coordinate neural activity, but its role in successful memory formation in the human cortex is unknown. Measures of PAC are difficult to interpret, however. Both increases and decreases in PAC have been linked to memory encoding, and PAC may arise due to different neural mechanisms. Here, we use a waveform analysis to examine PAC in the human cortex as participants with intracranial electrodes performed a paired associates memory task. We found that successful memory formation exhibited significant decreases in left temporal lobe and prefrontal cortical PAC, and these two regions exhibited changes in PAC within different frequency bands. Two underlying neural mechanisms, nested oscillations and sharp waveforms, were responsible for the changes in these regions. Our data therefore suggest that decreases in measured cortical PAC during episodic memory reflect two distinct underlying mechanisms that are anatomically segregated in the human brain. Published by Elsevier Inc.

  10. Dynamics and genetic fuzzy neural network vibration control design of a smart flexible four-bar linkage mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Rong Bao, E-mail: rongbao_nust@sina.com; Rui Xiaoting [Nanjing University of Science and Technology, Institute of Launch Dynamics (China); Tao Ling [Chinese Academy of Sciences (ASIPP), Institute of Plasma Physics (China)

    2012-11-15

    In this paper, a dynamic modeling method and an active vibration control scheme for a smart flexible four-bar linkage mechanism featuring piezoelectric actuators and strain gauge sensors are presented. The dynamics of this smart mechanism is described by the Discrete Time Transfer Matrix Method of Multibody System (MS-DTTMM). Then a nonlinear fuzzy neural network control is employed to suppress the vibration of this smart mechanism. For improving the dynamic performance of the fuzzy neural network, a genetic algorithm based on the MS-DTTMM is designed offline to tune the initial parameters of the fuzzy neural network. The MS-DTTMM avoids the global dynamics equations of the system, which results in the matrices involved are always very small, so the computational efficiency of the dynamic analysis and control system optimization can be greatly improved. Formulations of the method as well as a numerical simulation are given to demonstrate the proposed dynamic method and control scheme.

  11. Condition classification of small reciprocating compressor for refrigerators using artificial neural networks and support vector machines

    Science.gov (United States)

    Yang, Bo-Suk; Hwang, Won-Woo; Kim, Dong-Jo; Chit Tan, Andy

    2005-03-01

    The need to increase machine reliability and decrease production loss due to faulty products in highly automated line requires accurate and reliable fault classification technique. Wavelet transform and statistical method are used to extract salient features from raw noise and vibration signals. The wavelet transform decomposes the raw time-waveform signals into two respective parts in the time space and frequency domain. With wavelet transform prominent features can be obtained easily than from time-waveform analysis. This paper focuses on the development of an advanced signal classifier for small reciprocating refrigerator compressors using noise and vibration signals. Three classifiers, self-organising feature map, learning vector quantisation and support vector machine (SVM) are applied in training and testing for feature extraction and the classification accuracies of the techniques are compared to determine the optimum fault classifier. The classification technique selected for detecting faulty reciprocating refrigerator compressors involves artificial neural networks and SVMs. The results confirm that the classification technique can differentiate faulty compressors from healthy ones and with high flexibility and reliability.

  12. Fractional Snow Cover Mapping by Artificial Neural Networks and Support Vector Machines

    Science.gov (United States)

    Çiftçi, B. B.; Kuter, S.; Akyürek, Z.; Weber, G.-W.

    2017-11-01

    Snow is an important land cover whose distribution over space and time plays a significant role in various environmental processes. Hence, snow cover mapping with high accuracy is necessary to have a real understanding for present and future climate, water cycle, and ecological changes. This study aims to investigate and compare the design and use of artificial neural networks (ANNs) and support vector machines (SVMs) algorithms for fractional snow cover (FSC) mapping from satellite data. ANN and SVM models with different model building settings are trained by using Moderate Resolution Imaging Spectroradiometer surface reflectance values of bands 1-7, normalized difference snow index and normalized difference vegetation index as predictor variables. Reference FSC maps are generated from higher spatial resolution Landsat ETM+ binary snow cover maps. Results on the independent test data set indicate that the developed ANN model with hyperbolic tangent transfer function in the output layer and the SVM model with radial basis function kernel produce high FSC mapping accuracies with the corresponding values of R = 0.93 and R = 0.92, respectively.

  13. Performance Comparison Between Support Vector Regression and Artificial Neural Network for Prediction of Oil Palm Production

    Directory of Open Access Journals (Sweden)

    Mustakim Mustakim

    2016-02-01

    Full Text Available The largest region that produces oil palm in Indonesia has an important role in improving the welfare of society and economy. Oil palm has increased significantly in Riau Province in every period, to determine the production development for the next few years with the functions and benefits of oil palm carried prediction production results that were seen from time series data last 8 years (2005-2013. In its prediction implementation, it was done by comparing the performance of Support Vector Regression (SVR method and Artificial Neural Network (ANN. From the experiment, SVR produced the best model compared with ANN. It is indicated by the correlation coefficient of 95% and 6% for MSE in the kernel Radial Basis Function (RBF, whereas ANN produced only 74% for R2 and 9% for MSE on the 8th experiment with hiden neuron 20 and learning rate 0,1. SVR model generates predictions for next 3 years which increased between 3% - 6% from actual data and RBF model predictions.

  14. A comparative study of support vector machine, artificial neural network and bayesian classifier for mutagenicity prediction.

    Science.gov (United States)

    Sharma, Anju; Kumar, Rajnish; Varadwaj, Pritish Kumar; Ahmad, Ausaf; Ashraf, Ghulam Md

    2011-09-01

    Mutagenicity is the capability of a chemical to carry out mutations in genetic material of an organism. In order to curtail expensive drug failures due to mutagenicity found in late development or even in clinical trials, it is crucial to determine potential mutagenicity problems as early as possible. In this work we have proposed three different classifiers, i.e. Support Vector Machine (SVM), Artificial Neural Network (ANN) and bayesian classifiers, for the prediction of mutagenicity of compounds based on seventeen descriptors. Among the three classifiers Radial Basis Function (RBF) kernel based SVM classifier appeared to be more accurate for classifying the compounds under study on mutagens and non-mutagens. The overall prediction accuracy of SVM model was found to be 71.73% which was appreciably higher than the accuracy of ANN based classifier (59.72%) and bayesian classifier (66.61%). It suggests that SVM based prediction model can be used for predicting mutagenicity more accurately compared to ANN and bayesian classifier for data under consideration.

  15. Distracted and down: neural mechanisms of affective interference in subclinical depression.

    Science.gov (United States)

    Kaiser, Roselinde H; Andrews-Hanna, Jessica R; Spielberg, Jeffrey M; Warren, Stacie L; Sutton, Bradley P; Miller, Gregory A; Heller, Wendy; Banich, Marie T

    2015-05-01

    Previous studies have shown that depressed individuals have difficulty directing attention away from negative distractors, a phenomenon known as affective interference. However, findings are mixed regarding the neural mechanisms and network dynamics of affective interference. The present study addressed these issues by comparing neural activation during emotion-word and color-word Stroop tasks in participants with varying levels of (primarily subclinical) depression. Depressive symptoms predicted increased activation to negative distractors in areas of dorsal anterior cingulate cortex (dACC) and posterior cingulate cortex (PCC), regions implicated in cognitive control and internally directed attention, respectively. Increased dACC activity was also observed in the group-average response to incongruent distractors, suggesting that dACC activity during affective interference is related to overtaxed cognitive control. In contrast, regions of PCC were deactivated across the group in response to incongruent distractors, suggesting that PCC activity during affective interference represents task-independent processing. A psychophysiological interaction emerged in which higher depression predicted more positively correlated activity between dACC and PCC during affective interference, i.e. greater connectivity between cognitive control and internal-attention systems. These findings suggest that, when individuals high in depression are confronted by negative material, increased attention to internal thoughts and difficulty shifting resources to the external world interfere with goal-directed behavior. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  16. Neural prostheses in clinical applications--trends from precision mechanics towards biomedical microsystems in neurological rehabilitation.

    Science.gov (United States)

    Stieglitz, T; Schuettler, M; Koch, K P

    2004-04-01

    Neural prostheses partially restore body functions by technical nerve excitation after trauma or neurological diseases. External devices and implants have been developed since the early 1960s for many applications. Several systems have reached nowadays clinical practice: Cochlea implants help the deaf to hear, micturition is induced by bladder stimulators in paralyzed persons and deep brain stimulation helps patients with Parkinson's disease to participate in daily life again. So far, clinical neural prostheses are fabricated with means of precision mechanics. Since microsystem technology opens the opportunity to design and develop complex systems with a high number of electrodes to interface with the nervous systems, the opportunity for selective stimulation and complex implant scenarios seems to be feasible in the near future. The potentials and limitations with regard to biomedical microdevices are introduced and discussed in this paper. Target specifications are derived from existing implants and are discussed on selected applications that has been investigated in experimental research: a micromachined implant to interface a nerve stump with a sieve electrode, cuff electrodes with integrated electronics, and an epiretinal vision prosthesis.

  17. Lexical organization and competition in first and second languages: computational and neural mechanisms.

    Science.gov (United States)

    Li, Ping

    2009-06-01

    How does a child rapidly acquire and develop a structured mental organization for the vast number of words in the first years of life? How does a bilingual individual deal with the even more complicated task of learning and organizing two lexicons? It is only until recently have we started to examine the lexicon as a dynamical system with regard to its acquisition, representation, and organization. In this article, I outline a proposal based on our research that takes the dynamical approach to the lexicon, and I discuss how this proposal can be applied to account for lexical organization, structural representation, and competition within and between languages. In particular, I provide computational evidence based on the DevLex model, a self-organizing neural network model, and neuroimaging evidence based on functional magnetic resonance imaging (fMRI) studies, to illustrate how children and adults learn and represent the lexicon in their first and second languages. In the computational research, our goal has been to identify, through linguistically and developmentally realistic models, detailed cognitive mechanisms underlying the dynamic self-organizing processes in monolingual and bilingual lexical development; in the neuroimaging research, our goal has been to identify the neural substrates that subserve lexical organization and competition in the monolingual and the bilingual brain. In both cases, our findings lead to a better understanding of the interactive dynamics involved in the acquisition and representation of one or multiple languages. Copyright © 2009 Cognitive Science Society, Inc.

  18. Neural Mechanisms for Integrating Prior Knowledge and Likelihood in Value-Based Probabilistic Inference

    Science.gov (United States)

    Ting, Chih-Chung; Yu, Chia-Chen; Maloney, Laurence T.

    2015-01-01

    In Bayesian decision theory, knowledge about the probabilities of possible outcomes is captured by a prior distribution and a likelihood function. The prior reflects past knowledge and the likelihood summarizes current sensory information. The two combined (integrated) form a posterior distribution that allows estimation of the probability of different possible outcomes. In this study, we investigated the neural mechanisms underlying Bayesian integration using a novel lottery decision task in which both prior knowledge and likelihood information about reward probability were systematically manipulated on a trial-by-trial basis. Consistent with Bayesian integration, as sample size increased, subjects tended to weigh likelihood information more compared with prior information. Using fMRI in humans, we found that the medial prefrontal cortex (mPFC) correlated with the mean of the posterior distribution, a statistic that reflects the integration of prior knowledge and likelihood of reward probability. Subsequent analysis revealed that both prior and likelihood information were represented in mPFC and that the neural representations of prior and likelihood in mPFC reflected changes in the behaviorally estimated weights assigned to these different sources of information in response to changes in the environment. Together, these results establish the role of mPFC in prior-likelihood integration and highlight its involvement in representing and integrating these distinct sources of information. PMID:25632152

  19. Effects of multitasking-training on gray matter structure and resting state neural mechanisms.

    Science.gov (United States)

    Takeuchi, Hikaru; Taki, Yasuyuki; Nouchi, Rui; Hashizume, Hiroshi; Sekiguchi, Atsushi; Kotozaki, Yuka; Nakagawa, Seishu; Miyauchi, Carlos Makoto; Sassa, Yuko; Kawashima, Ryuta

    2014-08-01

    Multitasking (MT) constitutes engaging in two or more cognitive activities at the same time. MT-training improves performance on untrained MT tasks and alters the functional activity of the brain during MT. However, the effects of MT-training on neural mechanisms beyond MT-related functions are not known. We investigated the effects of 4 weeks of MT-training on regional gray matter volume (rGMV) and functional connectivity during rest (resting-FC) in young human adults. MT-training was associated with increased rGMV in three prefrontal cortical regions (left lateral rostral prefrontal cortex (PFC), dorsolateral PFC (DLPFC), and left inferior frontal junction), the left posterior parietal cortex, and the left temporal and lateral occipital areas as well as decreased resting-FC between the right DLPFC and an anatomical cluster around the ventral anterior cingulate cortex (ACC). Our findings suggest that participation in MT-training is as a whole associated with task-irrelevant plasticity (i.e., neural changes are not limited to certain specific task conditions) in regions and the network that are assumed to play roles in MT as well as diverse higher-order cognitive functions. We could not dissociate the effects of each task component and the diverse cognitive processes involved in MT because of the nature of the study, and these remain to be investigated. © 2013 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc.

  20. Two different mechanisms support selective attention at different phases of training

    Science.gov (United States)

    Cha, Kexin; Byers, Anna; Serences, John T.

    2017-01-01

    Selective attention supports the prioritized processing of relevant sensory information to facilitate goal-directed behavior. Studies in human subjects demonstrate that attentional gain of cortical responses can sufficiently account for attention-related improvements in behavior. On the other hand, studies using highly trained nonhuman primates suggest that reductions in neural noise can better explain attentional facilitation of behavior. Given the importance of selective information processing in nearly all domains of cognition, we sought to reconcile these competing accounts by testing the hypothesis that extensive behavioral training alters the neural mechanisms that support selective attention. We tested this hypothesis using electroencephalography (EEG) to measure stimulus-evoked visual responses from human subjects while they performed a selective spatial attention task over the course of ~1 month. Early in training, spatial attention led to an increase in the gain of stimulus-evoked visual responses. Gain was apparent within ~100 ms of stimulus onset, and a quantitative model based on signal detection theory (SDT) successfully linked the magnitude of this gain modulation to attention-related improvements in behavior. However, after extensive training, this early attentional gain was eliminated even though there were still substantial attention-related improvements in behavior. Accordingly, the SDT-based model required noise reduction to account for the link between the stimulus-evoked visual responses and attentional modulations of behavior. These findings suggest that training can lead to fundamental changes in the way attention alters the early cortical responses that support selective information processing. Moreover, these data facilitate the translation of results across different species and across experimental procedures that employ different behavioral training regimes. PMID:28654635

  1. Molecular and neural mechanisms of sex pheromone reception and processing in the silkmoth Bombyx mori

    Directory of Open Access Journals (Sweden)

    Takeshi eSakurai

    2014-03-01

    Full Text Available Male moths locate their mates using species-specific sex pheromones emitted by conspecific females. One striking feature of sex pheromone recognition in males is the high degree of specificity and sensitivity at all levels, from the primary sensory processes to behavior. The silkmoth Bombyx mori is an excellent model insect in which to decipher the underlying mechanisms of sex pheromone recognition due to its simple sex pheromone communication system, where a single pheromone component, bombykol, elicits the full sexual behavior of male moths. Various technical advancements that cover all levels of analysis from molecular to behavioral also allow the systematic analysis of pheromone recognition mechanisms. Sex pheromone signals are detected by pheromone receptors expressed in olfactory receptor neurons in the pheromone-sensitive sensilla trichodea on male antennae. The signals are transmitted to the first olfactory processing center, the antennal lobe (AL, and then are processed further in the higher centers (mushroom body and lateral protocerebrum to elicit orientation behavior towards females. In recent years, significant progress has been made elucidating the molecular mechanisms underlying the detection of sex pheromones. In addition, extensive studies of the AL and higher centers have provided insights into the neural basis of pheromone processing in the silkmoth brain. This review describes these latest advances, and discusses what these advances have revealed about the mechanisms underlying the specific and sensitive recognition of sex pheromones in the silkmoth.

  2. Selective disinhibition: A unified neural mechanism for predictive and post hoc attentional selection.

    Science.gov (United States)

    Sridharan, Devarajan; Knudsen, Eric I

    2015-11-01

    The natural world presents us with a rich and ever-changing sensory landscape containing diverse stimuli that constantly compete for representation in the brain. When the brain selects a stimulus as the highest priority for attention, it differentially enhances the representation of the selected, "target" stimulus and suppresses the processing of other, distracting stimuli. A stimulus may be selected for attention while it is still present in the visual scene (predictive selection) or after it has vanished (post hoc selection). We present a biologically inspired computational model that accounts for the prioritized processing of information about targets that are selected for attention either predictively or post hoc. Central to the model is the neurobiological mechanism of "selective disinhibition" - the selective suppression of inhibition of the representation of the target stimulus. We demonstrate that this mechanism explains major neurophysiological hallmarks of selective attention, including multiplicative neural gain, increased inter-trial reliability (decreased variability), and reduced noise correlations. The same mechanism also reproduces key behavioral hallmarks associated with target-distracter interactions. Selective disinhibition exhibits several distinguishing and advantageous features over alternative mechanisms for implementing target selection, and is capable of explaining the effects of selective attention over a broad range of real-world conditions, involving both predictive and post hoc biasing of sensory competition and decisions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Neural adaptations to resistive exercise: mechanisms and recommendations for training practices.

    Science.gov (United States)

    Gabriel, David A; Kamen, Gary; Frost, Gail

    2006-01-01

    It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are

  4. Genetic algorithm based on optimization of neural network structure for fault diagnosis of the clutch retainer mechanism of MF 285 tractor

    Directory of Open Access Journals (Sweden)

    S. F Mousavi

    2016-09-01

    Full Text Available Introduction The diagnosis of agricultural machinery faults must be performed at an opportune time, in order to fulfill the agricultural operations in a timely manner and to optimize the accuracy and the integrity of a system, proper monitoring and fault diagnosis of the rotating parts is required. With development of fault diagnosis methods of rotating equipment, especially bearing failure, the security, performance and availability of machines has been increasing. In general, fault detection is conducted through a specific procedure which starts with data acquisition and continues with features extraction, and subsequently failure of the machine would be detected. Several practical methods have been introduced for fault detection in rotating parts of machineries. The review of the literature shows that both Artificial Neural Networks (ANN and Support Vector Machines (SVM have been used for this purpose. However, the results show that SVM is more effective than Artificial Neural Networks in fault detection of such machineries. In some smart detection systems, incorporating an optimized method such as Genetic Algorithm in the Neural Network model, could improve the fault detection procedure. Consequently, the fault detection performance of neural networks may also be improved by combining with the Genetic Algorithm and hence will be comparable with the performance of the Support Vector Machine. In this study, the so called Genetic Algorithm (GA method was used to optimize the structure of the Artificial Neural Networks (ANN for fault detection of the clutch retainer mechanism of Massey Ferguson 285 tractor. Materials and Methods The test rig consists of some electro mechanical parts including the clutch retainer mechanism of Massey Ferguson 285 tractor, a supporting shaft, a single-phase electric motor, a loading mechanism to model the load of the tractor clutch and the corresponding power train gears. The data acquisition section consists of a

  5. Age and gender modulate the neural circuitry supporting facial emotion processing in adults with major depressive disorder.

    Science.gov (United States)

    Briceño, Emily M; Rapport, Lisa J; Kassel, Michelle T; Bieliauskas, Linas A; Zubieta, Jon-Kar; Weisenbach, Sara L; Langenecker, Scott A

    2015-03-01

    Emotion processing, supported by frontolimbic circuitry known to be sensitive to the effects of aging, is a relatively understudied cognitive-emotional domain in geriatric depression. Some evidence suggests that the neurophysiological disruption observed in emotion processing among adults with major depressive disorder (MDD) may be modulated by both gender and age. Therefore, the present study investigated the effects of gender and age on the neural circuitry supporting emotion processing in MDD. Cross-sectional comparison of fMRI signal during performance of an emotion processing task. Outpatient university setting. One hundred adults recruited by MDD status, gender, and age. Participants underwent fMRI while completing the Facial Emotion Perception Test. They viewed photographs of faces and categorized the emotion perceived. Contrast for fMRI was of face perception minus animal identification blocks. Effects of depression were observed in precuneus and effects of age in a number of frontolimbic regions. Three-way interactions were present between MDD status, gender, and age in regions pertinent to emotion processing, including frontal, limbic, and basal ganglia. Young women with MDD and older men with MDD exhibited hyperactivation in these regions compared with their respective same-gender healthy comparison (HC) counterparts. In contrast, older women and younger men with MDD exhibited hypoactivation compared to their respective same-gender HC counterparts. This the first study to report gender- and age-specific differences in emotion processing circuitry in MDD. Gender-differential mechanisms may underlie cognitive-emotional disruption in older adults with MDD. The present findings have implications for improved probes into the heterogeneity of the MDD syndrome. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

  6. Outsourcing neural active control to passive composite mechanics: a tissue engineered cyborg ray

    Science.gov (United States)

    Gazzola, Mattia; Park, Sung Jin; Park, Kyung Soo; Park, Shirley; di Santo, Valentina; Deisseroth, Karl; Lauder, George V.; Mahadevan, L.; Parker, Kevin Kit

    2016-11-01

    Translating the blueprint that stingrays and skates provide, we create a cyborg swimming ray capable of orchestrating adaptive maneuvering and phototactic navigation. The impossibility of replicating the neural system of batoids fish is bypassed by outsourcing algorithmic functionalities to the body composite mechanics, hence casting the active control problem into a design, passive one. We present a first step in engineering multilevel "brain-body-flow" systems that couple sensory information to motor coordination and movement, leading to behavior. This work paves the way for the development of autonomous and adaptive artificial creatures able to process multiple sensory inputs and produce complex behaviors in distributed systems and may represent a path toward soft-robotic "embodied cognition".

  7. Understanding the neural mechanisms involved in sensory control of voice production.

    Science.gov (United States)

    Parkinson, Amy L; Flagmeier, Sabina G; Manes, Jordan L; Larson, Charles R; Rogers, Bill; Robin, Donald A

    2012-05-15

    Auditory feedback is important for the control of voice fundamental frequency (F0). In the present study we used neuroimaging to identify regions of the brain responsible for sensory control of the voice. We used a pitch-shift paradigm where subjects respond to an alteration, or shift, of voice pitch auditory feedback with a reflexive change in F0. To determine the neural substrates involved in these audio-vocal responses, subjects underwent fMRI scanning while vocalizing with or without pitch-shifted feedback. The comparison of shifted and unshifted vocalization revealed activation bilaterally in the superior temporal gyrus (STG) in response to the pitch shifted feedback. We hypothesize that the STG activity is related to error detection by auditory error cells located in the superior temporal cortex and efference copy mechanisms whereby this region is responsible for the coding of a mismatch between actual and predicted voice F0. Published by Elsevier Inc.

  8. Inclusion mechanical property estimation using tactile images, finite element method, and artificial neural network.

    Science.gov (United States)

    Lee, Jong-Ha; Won, Chang-Hee

    2011-01-01

    In this paper, we developed a methodology for estimating three parameters of tissue inclusion: size, depth, and Young's modulus from the tactile data obtained at the tissue surface with the tactile sensation imaging system. The estimation method consists of the forward algorithm using finite element method, and inversion algorithm using artificial neural network. The forward algorithm is designed to comprehensively predict the tactile data based on the mechanical properties of the tissue inclusion. This forward information is used to develop an inversion algorithm that will be used to extract the size, depth, and Young's modulus of a tissue inclusion from the tactile image. The proposed method is then validated with custom made tissue phantoms with matching elasticities of typical human breast tissues. The experimental results showed that the proposed estimation method estimates the size, depth, and Young's modulus of tissue inclusions with root mean squared errors of 1.25 mm, 2.09 mm, and 28.65 kPa, respectively.

  9. Mechanisms of drop formation in air-supported spray boxes

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, S.; Sattelmayer, T.; Aigner, M.; Sakbani, K.

    1985-10-01

    In the course of further development of gas turbine combustion chambers, the fuel spraying was comprehensively investigated. The air-supported sprayer with liquid film in the nozzle (air blast nozzle) enables a reduction of the emission of noxious matter and shows a favourable operational behaviour. The basic mechanisms were investigated with the help of models and their possible transfer checked with test nozzles. The influences of the physical properties of the fuel, of the geometry and the operational parameter on the film formation and disintegration as well as the produced drop spectrum could be clarified in detail. (orig.).

  10. Mechanical strengthening of fiberoptic microneedles using an elastomeric support.

    Science.gov (United States)

    Kosoglu, Mehmet A; Hood, R Lyle; Rylander, Christopher G

    2012-07-01

    Microneedles made from silica fiberoptics permit transmission and collection of light, which is an important functional advantage over metal or silicon microneedles. This added functionality may enhance or even enable new percutaneous light-based clinical diagnostic and therapeutic procedures. Micron-diameter fiberoptic microneedles, created from solid fibers capable of light emission and detection, are designed to penetrate several millimeters into tissue while minimizing tissue invasion and disruption. The mechanical strength (critical buckling force) of high aspect ratio (length to diameter) microneedles is a potential problem, which has motivated our invention of an elastomeric support device. In this study, we have tested our hypothesis that embedding the microneedles in an elastomeric support medium may increase microneedle critical buckling force. The critical buckling force of silica microneedles with 55, 70, and 110 µm diameters and 3 mm lengths were measured with and without a surrounding elastomeric support (PDMS, polydimethylsiloxane). These experimental results were compared to theoretical calculations generated by the Rayleigh-Ritz buckling model. The insertion force required to penetrate ex vivo porcine skin was measured for microneedles with 55 and 70 µm diameters. Use of the PDMS support increased critical buckling force for microneedles of 55, 70, and 110 µm diameters by an average of 610%, 290%, and 33%, respectively. Theoretical calculations by the Rayleigh-Ritz model consistently overestimated the experimentally determined strengthening, but correlated highly with the greater enhancement offered to thinner microneedles. Aided by mechanical strengthening, microneedles 55 µm in diameter were able to repeatedly penetrate. The critical buckling force of microneedles can be increased substantially to allow extremely high-aspect ratio microneedles, 55-110 µm in diameter and 3 mm in length, to penetrate ex vivo porcine skin. By this strengthening

  11. Two distinct neural mechanisms in early visual cortex determine subsequent visual processing.

    Science.gov (United States)

    Jacobs, Christianne; de Graaf, Tom A; Sack, Alexander T

    2014-10-01

    Neuroscience research has conventionally focused on how the brain processes sensory information, after the information has been received. Recently, increased interest focuses on how the state of the brain upon receiving inputs determines and biases their subsequent processing and interpretation. Here, we investigated such 'pre-stimulus' brain mechanisms and their relevance for objective and subjective visual processing. Using non-invasive focal brain stimulation [transcranial magnetic stimulation (TMS)] we disrupted spontaneous brain state activity within early visual cortex (EVC) before onset of visual stimulation, at two different pre-stimulus-onset-asynchronies (pSOAs). We found that TMS pulses applied to EVC at either 20 msec or 50 msec before onset of a simple orientation stimulus both prevented this stimulus from reaching visual awareness. Interestingly, only the TMS-induced visual suppression following TMS at a pSOA of ?20 msec was retinotopically specific, while TMS at a pSOA of ?50 msec was not. In a second experiment, we used more complex symbolic arrow stimuli, and found TMS-induced suppression only when disrupting EVC at a pSOA of ? ?60 msec, which, in line with Experiment 1, was not retinotopically specific. Despite this topographic unspecificity of the ?50 msec effect, the additional control measurements as well as tracking and removal of eye blinks, suggested that also this effect was not the result of an unspecific artifact, and thus neural in origin. We therefore obtained evidence of two distinct neural mechanisms taking place in EVC, both determining whether or not subsequent visual inputs are successfully processed by the human visual system.

  12. Neural Correlates of Successful and Unsuccessful Strategical Mechanisms Involved in Uncertain Decision-Making.

    Directory of Open Access Journals (Sweden)

    Julie Giustiniani

    Full Text Available The ability to develop successful long-term strategies in uncertain situations relies on complex neural mechanisms. Although lesion studies have shown some of the mechanisms involved, it is still unknown why some healthy subjects are able to make the right decision whereas others are not. The aim of our study was to investigate neurophysiological differences underlying this ability to develop a successful strategy in a group of healthy subjects playing a monetary card game called the Iowa Gambling Task (IGT. In this task, subjects have to win and earn money by choosing between four decks of cards, two were advantageous in the long term and two disadvantageous. Twenty healthy right-handed subjects performed the IGT while their cerebral activity was recorded by electroencephalography. Based on their behavioral performances, two groups of subjects could clearly be distinguished: one who selected the good decks and thus succeeded in developing a Favorable strategy (9 subjects and one who remained Undecided (11 subjects. No neural difference was found between each group before the selection of a deck, but in both groups a greater negativity was found emerging from the right superior frontal gyrus 600 ms before a disadvantageous selection. During the processing of the feedback, an attenuation of the P200 and P300 waveforms was found for the Undecided group, and a P300 originating from the medial frontal gyrus was found in response to a loss only in the Favorable group. Our results suggest that undecided subjects are hyposensitive to the valence of the cards during gambling, which affects the feedback processing.

  13. Neural Correlates of Successful and Unsuccessful Strategical Mechanisms Involved in Uncertain Decision-Making.

    Science.gov (United States)

    Giustiniani, Julie; Gabriel, Damien; Nicolier, Magali; Monnin, Julie; Haffen, Emmanuel

    2015-01-01

    The ability to develop successful long-term strategies in uncertain situations relies on complex neural mechanisms. Although lesion studies have shown some of the mechanisms involved, it is still unknown why some healthy subjects are able to make the right decision whereas others are not. The aim of our study was to investigate neurophysiological differences underlying this ability to develop a successful strategy in a group of healthy subjects playing a monetary card game called the Iowa Gambling Task (IGT). In this task, subjects have to win and earn money by choosing between four decks of cards, two were advantageous in the long term and two disadvantageous. Twenty healthy right-handed subjects performed the IGT while their cerebral activity was recorded by electroencephalography. Based on their behavioral performances, two groups of subjects could clearly be distinguished: one who selected the good decks and thus succeeded in developing a Favorable strategy (9 subjects) and one who remained Undecided (11 subjects). No neural difference was found between each group before the selection of a deck, but in both groups a greater negativity was found emerging from the right superior frontal gyrus 600 ms before a disadvantageous selection. During the processing of the feedback, an attenuation of the P200 and P300 waveforms was found for the Undecided group, and a P300 originating from the medial frontal gyrus was found in response to a loss only in the Favorable group. Our results suggest that undecided subjects are hyposensitive to the valence of the cards during gambling, which affects the feedback processing.

  14. Neural Mechanisms for Acoustic Signal Detection under Strong Masking in an Insect.

    Science.gov (United States)

    Kostarakos, Konstantinos; Römer, Heiner

    2015-07-22

    produces an extremely noisy sound, yet the second species still detects its own song. Using intracellular recording techniques we identified two neural mechanisms underlying the surprising behavioral signal detection at the level of single identified interneurons. These neural mechanisms for signal detection are likely to be important for other sensory modalities as well, where noise in the communication channel creates similar problems. Also, they may be used for the development of algorithms for the filtering of specific signals in technical microphones or hearing aids. Copyright © 2015 Kostarakos and Römer.

  15. Conditioned task-set competition: Neural mechanisms of emotional interference in depression.

    Science.gov (United States)

    Stolicyn, Aleks; Steele, J Douglas; Seriès, Peggy

    2017-04-01

    Depression has been associated with increased response times at the incongruent-, neutral-, and negative-word trials of the classical and emotional Stroop tasks (Epp et al., Clinical Psychology Review, 32, 316-328, 2012). Response-time slowdown effects at incongruent- and negative-word trials of the Stroop tasks were reported to correlate with depressive severity, indicating strong relevance of the effects to the symptomatology. This study proposes a novel integrative computational model of neural mechanisms of both the classical and emotional Stroop effects, drawing on the previous prominent theoretical explanations of performance at the classical Stroop task (Cohen, Dunbar, & McClelland, Psychological Review, 97, 332-361, 1990; Herd, Banich, & O'Reilly, Journal of Cognitive Neuroscience, 18, 22-32, 2006), and in addition suggesting that negative emotional words represent conditioned stimuli for future negative outcomes. The model is shown to explain the classical Stroop effect and the slow (between-trial) emotional Stroop effect with biologically plausible mechanisms, providing an advantage over the previous theoretical accounts (Matthews & Harley, Cognition & Emotion, 10, 561-600, 1996; Wyble, Sharma, & Bowman, Cognition & Emotion, 22, 1019-1051, 2008). Simulation results suggested a candidate mechanism responsible for the pattern of depressive performance at the classical and the emotional Stroop tasks. Hyperactivity of the amygdala, together with increased inhibitory influence of the amygdala over dopaminergic neurotransmission, could be at the origin of the performance deficits.

  16. The Mechanisms for the State Supporting the Development of Corporations

    Directory of Open Access Journals (Sweden)

    Riabokin Taras V.

    2017-01-01

    Full Text Available The main aim of the article is the theoretical substantiation of the necessity to build an efficient mechanism for the State supporting the corporate development, taking account of the main national and corporate interests. As result of processing and analyzing the available scientific-methodological and practical approaches to development of corporations and the State impact on this process, the phased scheme of the corporate development has been proposed, defining the main corporate and national priorities in each of the stages. On the basis of the administrative, fiscal, and monetary methods, the key directions for coordination of development of the individual corporations have been allocated and a mechanism for the State support has been proposed, implementation of which will provide to harmonize the public and the corporate interests, achieve the total recovery of the national economy. It has been pointed out to the need of creating on the basis of the powerful corporations an effective system of the corporate social responsibility as one of the main directions for harmonization of the national and the corporate interests. Promising directions for further research will be solving the problems associated with the long-term investment in the corporate development, determining and then minimizing the major risks at the stage of appearance of corporations at the international level.

  17. Neural mechanisms underlying stop-and-restart difficulties: involvement of the motor and perceptual systems.

    Directory of Open Access Journals (Sweden)

    Kentaro Yamanaka

    Full Text Available The ability to suddenly stop a planned movement or a movement being performed and restart it after a short interval is an important mechanism that allows appropriate behavior in response to contextual or environmental changes. However, performing such stop-and-restart movements smoothly is difficult at times. We investigated performance (response time of stop-and-restart movements using a go/stop/re-go task and found consistent stop-and-restart difficulties after short (~100 ms stop-to-restart intervals (SRSI, and an increased probability of difficulties after longer (>200 ms SRSIs, suggesting that two different mechanisms underlie stop-and-restart difficulties. Next, we investigated motor evoked potentials (MEPs in a moving muscle induced by transcranial magnetic stimulation during a go/stop/re-go task. In re-go trials with a short SRSI (100 ms, the MEP amplitude continued to decrease after the re-go-signal onset, indicating that stop-and-restart difficulties with short SRSIs might be associated with a neural mechanism in the human motor system, namely, stop-related suppression of corticomotor (CM excitability. Finally, we recorded electroencephalogram (EEG activity during a go/stop/re-go task and performed a single-trial-based EEG power and phase time-frequency analysis. Alpha-band EEG phase locking to re-go-signal, which was only observed in re-go trials with long SRSI (250 ms, weakened in the delayed re-go response trials. These EEG phase dynamics indicate an association between stop-and-restart difficulties with long SRSIs and a neural mechanism in the human perception system, namely, decreased probability of EEG phase locking to visual stimuli. In contrast, smooth stop-and-restart human movement can be achieved in re-go trials with sufficient SRSI (150-200 ms, because release of stop-related suppression and simultaneous counter-activation of CM excitability may occur as a single task without second re-go-signal perception. These results

  18. Neural mechanisms underlying stop-and-restart difficulties: involvement of the motor and perceptual systems.

    Science.gov (United States)

    Yamanaka, Kentaro; Nozaki, Daichi

    2013-01-01

    The ability to suddenly stop a planned movement or a movement being performed and restart it after a short interval is an important mechanism that allows appropriate behavior in response to contextual or environmental changes. However, performing such stop-and-restart movements smoothly is difficult at times. We investigated performance (response time) of stop-and-restart movements using a go/stop/re-go task and found consistent stop-and-restart difficulties after short (~100 ms) stop-to-restart intervals (SRSI), and an increased probability of difficulties after longer (>200 ms) SRSIs, suggesting that two different mechanisms underlie stop-and-restart difficulties. Next, we investigated motor evoked potentials (MEPs) in a moving muscle induced by transcranial magnetic stimulation during a go/stop/re-go task. In re-go trials with a short SRSI (100 ms), the MEP amplitude continued to decrease after the re-go-signal onset, indicating that stop-and-restart difficulties with short SRSIs might be associated with a neural mechanism in the human motor system, namely, stop-related suppression of corticomotor (CM) excitability. Finally, we recorded electroencephalogram (EEG) activity during a go/stop/re-go task and performed a single-trial-based EEG power and phase time-frequency analysis. Alpha-band EEG phase locking to re-go-signal, which was only observed in re-go trials with long SRSI (250 ms), weakened in the delayed re-go response trials. These EEG phase dynamics indicate an association between stop-and-restart difficulties with long SRSIs and a neural mechanism in the human perception system, namely, decreased probability of EEG phase locking to visual stimuli. In contrast, smooth stop-and-restart human movement can be achieved in re-go trials with sufficient SRSI (150-200 ms), because release of stop-related suppression and simultaneous counter-activation of CM excitability may occur as a single task without second re-go-signal perception. These results suggest that

  19. Neural model of gene regulatory network: a survey on supportive meta-heuristics.

    Science.gov (United States)

    Biswas, Surama; Acharyya, Sriyankar

    2016-06-01

    Gene regulatory network (GRN) is produced as a result of regulatory interactions between different genes through their coded proteins in cellular context. Having immense importance in disease detection and drug finding, GRN has been modelled through various mathematical and computational schemes and reported in survey articles. Neural and neuro-fuzzy models have been the focus of attraction in bioinformatics. Predominant use of meta-heuristic algorithms in training neural models has proved its excellence. Considering these facts, this paper is organized to survey neural modelling schemes of GRN and the efficacy of meta-heuristic algorithms towards parameter learning (i.e. weighting connections) within the model. This survey paper renders two different structure-related approaches to infer GRN which are global structure approach and substructure approach. It also describes two neural modelling schemes, such as artificial neural network/recurrent neural network based modelling and neuro-fuzzy modelling. The meta-heuristic algorithms applied so far to learn the structure and parameters of neutrally modelled GRN have been reviewed here.

  20. Decision Support System for Age-Related Macular Degeneration Using Convolutional Neural Networks

    Directory of Open Access Journals (Sweden)

    Mostafa Langarizadeh

    2017-09-01

    Full Text Available Introduction: Age-related macular degeneration (AMD is one of the major causes of visual loss among the elderly. It causes degeneration of cells in the macula. Early diagnosis can be helpful in preventing blindness. Drusen are the initial symptoms of AMD. Since drusen have a wide variety, locating them in screening images is difficult and time-consuming. An automated digital fundus photography-based screening system help overcome such drawbacks. The main objective of this study was to suggest a novel method to classify AMD and normal retinal fundus images. Materials and Methods: The suggested system was developed using convolutional neural networks. Several methods were adopted for increasing data such as horizontal reflection, random crop, as well as transfer and combination of such methods. The suggested system was evaluated using images obtained from STARE database and a local dataset. Results: The local dataset contained 3195 images (2070 images of AMD suspects and 1125 images of healthy retina and the STARE dataset comprised of 201 images (105 images of AMD suspects and 96 images of healthy retina. According to the results, the accuracies of the local and standard datasets were 0.95 and 0.81, respectively. Conclusion: Diagnosis and screening of AMD is a time-consuming task for specialists. To overcome this limitation, we attempted to design an intelligent decision support system for the diagnosis of AMD fundus using retina images. The proposed system is an important step toward providing a reliable tool for supervising patients. Early diagnosis of AMD can lead to timely access to treatment.

  1. The Mechanical Properties of the Space Frame Supporting Detectors

    CERN Document Server

    CERN. Geneva

    1997-01-01

    The note contains the results of the frame space analysis. The frame space is designed to carry the detectors and is to be slid into position parallel to the beam direction. From the mechanics point of view all the detectors are loads (masses) applied to the frame. The frame, in turn, is based on two long rails supported at their ends only. The analysis was performed in stages, starting with a given design and successively including additional requirements. At the first step there was a given design (layout of members and a profile) and loads coming from the HMPIDs, the Pestov detectors and the TPC. At the second step the layout was changed in order to avoid any frame member in the shadow of the HMPIDs. The third step introduced changes in profile dimensions so as to yield space needed for the TRDs, which were added to the loads. The job is done in the frame of the collaboration between CERN and the Institute of Mechanics and Machine Design of the Mechanical Department of the Cracow University of Technology, ...

  2. KOMPARASI MODEL SUPPORT VECTOR MACHINES (SVM DAN NEURAL NETWORK UNTUK MENGETAHUI TINGKAT AKURASI PREDIKSI TERTINGGI HARGA SAHAM

    Directory of Open Access Journals (Sweden)

    R. Hadapiningradja Kusumodestoni

    2017-09-01

    Full Text Available There are many types of investments to make money, one of which is in the form of shares. Shares is a trading company dealing with securities in the global capital markets. Stock Exchange or also called stock market is actually the activities of private companies in the form of buying and selling investments. To avoid losses in investing, we need a model of predictive analysis with high accuracy and supported by data - lots of data and accurately. The correct techniques in the analysis will be able to reduce the risk for investors in investing. There are many models used in the analysis of stock price movement prediction, in this study the researchers used models of neural networks (NN and a model of support vector machine (SVM. Based on the background of the problems that have been mentioned in the previous description it can be formulated the problem as follows: need an algorithm that can predict stock prices, and need a high accuracy rate by adding a data set on the prediction, two algorithms will be investigated expected results last researchers can deduce where the algorithm accuracy rate predictions are the highest or accurate, then the purpose of this study was to mengkomparasi or compare between the two algorithms are algorithms Neural Network algorithm and Support Vector Machine which later on the end result has an accuracy rate forecast stock prices highest to see the error value RMSEnya. After doing research using the model of neural network and model of support vector machine (SVM to predict the stock using the data value of the shares on the stock index hongkong dated July 20, 2016 at 16:26 pm until the date of 15 September 2016 at 17:40 pm as many as 729 data sets within an interval of 5 minute through a process of training, learning, and then continue the process of testing so the result is that by using a neural network model of the prediction accuracy of 0.503 +/- 0.009 (micro 503 while using the model of support vector machine

  3. Neural mechanisms of individual differences in temporal discounting of monetary and primary rewards in adolescents.

    Science.gov (United States)

    de Water, Erik; Mies, Gabry W; Figner, Bernd; Yoncheva, Yuliya; van den Bos, Wouter; Castellanos, F Xavier; Cillessen, Antonius H N; Scheres, Anouk

    2017-06-01

    Adolescents are generally characterized as impulsive. However, impulsivity is a multi-dimensional construct that involves multiple component processes. Which of these components contribute to adolescent impulsivity is currently unclear. This study focused on the neural mechanisms underlying individual differences in distinct components of temporal discounting (TD), i.e., the preference for smaller immediate rewards over larger delayed rewards. Participants were 58 adolescents (12-16 years-old) who performed an fMRI TD task with both monetary and snack rewards. Using mixed-effects modeling, we determined participants' average impatience, and further decomposed TD choices into: 1) amount sensitivity (unique contribution of the magnitude of the immediate reward); and 2) delay sensitivity (unique contribution of delay duration). Adolescents' average impatience was positively correlated with frontoparietal and ventral striatal activity during delayed reward choices, and with ventromedial prefrontal cortex activity during immediate reward choices. Adolescents' amount sensitivity was positively associated with ventral striatal and dorsal anterior cingulate cortex activity during immediate reward choices. Delay sensitivity was positively correlated with inferior parietal cortex activity during delayed reward choices. As expected, snacks were discounted more steeply than money, and TD of both reward types was associated with overlapping activation in the inferior parietal cortex. Exploring whether testosterone or estradiol were associated with TD and its neural correlates revealed no significant associations. These findings indicate that distinct components contribute uniquely to TD choice and that individual differences in amount sensitivity are uniquely associated with activation of reward valuation areas, while individual differences in delay sensitivity are uniquely associated with activation of cognitive control areas. Copyright © 2017 Elsevier Inc. All rights

  4. A novel Fizzy/Cdc20-dependent mechanism suppresses necrosis in neural stem cells

    Science.gov (United States)

    Kuang, Chaoyuan; Golden, Krista L.; Simon, Claudio R.; Damrath, John; Buttitta, Laura; Gamble, Caitlin E.; Lee, Cheng-Yu

    2014-01-01

    Cancer stem cells likely survive chemotherapy or radiotherapy by acquiring mutations that inactivate the endogenous apoptotic machinery or by cycling slowly. Thus, knowledge about the mechanisms linking the activation of an alternative cell death modality and the cell cycle machinery could have a transformative impact on the development of new cancer therapies, but the mechanisms remain completely unknown. We investigated the regulation of alternative cell death in Drosophila larval brain neural stem cells (neuroblasts) in which apoptosis is normally repressed. From a screen, we identified two novel loss-of-function alleles of the Cdc20/fizzy (fzy) gene that lead to premature brain neuroblast loss without perturbing cell proliferation in other diploid cell types. Fzy is an evolutionarily conserved regulator of anaphase promoting complex/cyclosome (APC/C). Neuroblasts carrying the novel fzy allele or exhibiting reduced APC/C function display hallmarks of necrosis. By contrast, neuroblasts overexpressing the non-degradable form of canonical APC/C substrates required for cell cycle progression undergo mitotic catastrophe. These data strongly suggest that Fzy can elicit a novel pro-survival function of APC/C by suppressing necrosis. Neuroblasts experiencing catastrophic cellular stress, or overexpressing p53, lose Fzy expression and undergo necrosis. Co-expression of fzy suppresses the death of these neuroblasts. Consequently, attenuation of the Fzy-dependent survival mechanism functions downstream of catastrophic cellular stress and p53 to eliminate neuroblasts by necrosis. Strategies that target the Fzy-dependent survival mechanism might lead to the discovery of new treatments or complement the pre-existing therapies to eliminate apoptosis-resistant cancer stem cells by necrosis. PMID:24598157

  5. Mechanisms for Interferon-α-Induced Depression and Neural Stem Cell Dysfunction

    Directory of Open Access Journals (Sweden)

    Lian-Shun Zheng

    2014-07-01

    Full Text Available New neurons generated by the neural stem cells (NSCs in the adult hippocampus play an important role in emotional regulation and respond to the action of antidepressants. Depression is a common and serious side effect of interferon-α (IFN-α, which limits its use as an antiviral and antitumor drug. However, the mechanism(s underlying IFN-induced depression are largely unknown. Using a comprehensive battery of behavioral tests, we found that mice subjected to IFN-α treatment exhibited a depression-like phenotype. IFN-α directly suppressed NSC proliferation, resulting in the reduced generation of new neurons. Brain-specific mouse knockout of the IFN-α receptor prevented IFN-α-induced depressive behavioral phenotypes and the inhibition of neurogenesis, suggesting that IFN-α suppresses hippocampal neurogenesis and induces depression via its receptor in the brain. These findings provide insight for understanding the neuropathology underlying IFN-α-induced depression and for developing new strategies for the prevention and treatment of IFN-α-induced depressive effects.

  6. The uptake mechanism and biocompatibility of graphene quantum dots with human neural stem cells

    Science.gov (United States)

    Shang, Weihu; Zhang, Xiaoyan; Zhang, Mo; Fan, Zetan; Sun, Ying; Han, Mei; Fan, Louzhen

    2014-05-01

    Cellular imaging after transplantation may provide important information to determine the efficacy of stem cell therapy. We have reported that graphene quantum dots (GQDs) are a type of robust biological labeling agent for stem cells that demonstrate little cytotoxicity. In this study, we examined the interactions of GQDs on human neural stem cells (hNSCs) with the aim to investigate the uptake and biocompatibility of GQDs. We examined the mechanism of GQD uptake by hNSCs and investigated the effects of GQDs on the proliferation, metabolic activity, and differentiation potential of hNSCs. This information is critical to assess the suitability of GQDs for stem cell tracking. Our results indicated that GQDs were taken up into hNSCs in a concentration- and time-dependent manner via the endocytosis mechanism. Furthermore, no significant change was found in the viability, proliferation, metabolic activity, and differentiation potential of hNSCs after treatment with GQDs. Thus, these data open a promising avenue for labeling stem cells with GQDs and also offer a potential opportunity to develop GQDs for biomedical applications.

  7. Staying cool when things get hot: Emotion regulation modulates neural mechanisms of memory encoding

    Directory of Open Access Journals (Sweden)

    Jasmeet P Hayes

    2010-12-01

    Full Text Available During times of emotional stress, individuals often engage in emotion regulation to reduce the experiential and physiological impact of negative emotions. Interestingly, emotion regulation strategies also influence memory encoding of the event. Cognitive reappraisal is associated with enhanced memory while expressive suppression is associated with impaired explicit memory of the emotional event. However, the mechanism by which these emotion regulation strategies affect memory is unclear. We used event-related fMRI to investigate the neural mechanisms that give rise to memory formation during emotion regulation. Twenty-five participants viewed negative pictures while alternately engaging in cognitive reappraisal, expressive suppression, or passive viewing. As part of the subsequent memory design, participants returned to the laboratory two weeks later for a surprise memory test. Behavioral results showed a reduction in negative affect and a retention advantage for reappraised stimuli relative to the other conditions. Imaging results showed that successful encoding during reappraisal was uniquely associated with greater co-activation of the left inferior frontal gyrus, amygdala and hippocampus, suggesting a possible role for elaborative encoding of negative memories. This study provides neurobehavioral evidence that engaging in cognitive reappraisal is advantageous to both affective and mnemonic processes.

  8. Fracture Mechanics Method for Word Embedding Generation of Neural Probabilistic Linguistic Model

    Directory of Open Access Journals (Sweden)

    Size Bi

    2016-01-01

    Full Text Available Word embedding, a lexical vector representation generated via the neural linguistic model (NLM, is empirically demonstrated to be appropriate for improvement of the performance of traditional language model. However, the supreme dimensionality that is inherent in NLM contributes to the problems of hyperparameters and long-time training in modeling. Here, we propose a force-directed method to improve such problems for simplifying the generation of word embedding. In this framework, each word is assumed as a point in the real world; thus it can approximately simulate the physical movement following certain mechanics. To simulate the variation of meaning in phrases, we use the fracture mechanics to do the formation and breakdown of meaning combined by a 2-gram word group. With the experiments on the natural linguistic tasks of part-of-speech tagging, named entity recognition and semantic role labeling, the result demonstrated that the 2-dimensional word embedding can rival the word embeddings generated by classic NLMs, in terms of accuracy, recall, and text visualization.

  9. Application of ICT supported learning in fluid mechanics

    DEFF Research Database (Denmark)

    Brohus, Henrik; Svidt, Kjeld

    2004-01-01

    actively in the learning environment to increase efficiency in the learning process. The paper comprises past experiences and lessons learnt as well as prospect for future development in the area. A model is presented that describes a high efficiency learning environment where ICT plays an important role...... learning tools is presented. The model describes the teaching method and the pedagogical means. It explains how different learning domains ? physical as virtual ? may be combined to form a high efficiency learning environment (HELE).......This paper focuses on the application of ICT, Information & Communication Technology, supported learning in the area of fluid mechanics education. Taking a starting point in a course in Ventilation Technology, including room air flow and contaminant distribution, it explains how ICT may be used...

  10. Advanced pulmonary arterial hypertension: mechanical support and lung transplantation

    Directory of Open Access Journals (Sweden)

    Sonja Bartolome

    2017-12-01

    Full Text Available The development of targeted therapies has transformed the outlook for patients with pulmonary arterial hypertension (PAH; however, some patients fail to achieve an adequate clinical response despite receiving maximal treatment. For these patients, lung transplantation remains an important therapeutic option, and recommendations for transplantation are included in the current European Society of Cardiology/European Respiratory Society guidelines for the diagnosis and treatment of pulmonary hypertension. Although lung transplantation is not without risk, overall long-term survival rates are good and substantial improvements in quality of life have been reported for lung transplant recipients. In this review, we describe the important considerations prior to, during and after transplantation, including the role of mechanical support, in patients with advanced PAH.

  11. A method for anticoagulation of children on mechanical circulatory support.

    Science.gov (United States)

    Copeland, Hannah; Nolan, Paul E; Covington, Diane; Gustafson, Monica; Smith, Richard; Copeland, Jack G

    2011-11-01

    Anticoagulation of children on mechanical circulatory support presents a challenge. We implanted 28 devices in children and infants using a consistent anticoagulation protocol. We performed a retrospective review of all children implanted in our program with mechanical assist devices since 1997. Heparin, dipyridamole, and aspirin were used for anticoagulation and antiaggregation. Coagulation monitoring included thromboelastography (TEG), platelet aggregration studies, international normalized ratio, partial thromboplastin time, and platelet count. Twenty-eight children, ages 1 month to 16 years (mean 5.3; median 2.4 years), were implanted for 3-107 days (mean 27; median 17). Eighteen received left ventricular assist devices, seven received biventricular assist devices, and three received total artificial hearts. Adverse events during the 720 days of device support included the following: six (21%) reoperations for bleeding; seven strokes (25%): two fatal, two with a mild residual deficit, and three without deficit; and three (11%) visceral emboli: two fatal and one nonfatal. There were eight deaths (29%). Causes of death were embolic (four), graft failure post-transplantation (one), preimplant anoxic brain damage (two), and postexplant heart failure (one). 24/28 (86%) survived to transplantation or weaning from device and 20/28 (71%) were discharged from the hospital, 10 after transplantation and 10 after native heart recovery. All 20 early survivors survived long term. We describe an anticoagulation protocol based upon TEG and platelet aggregation studies and using heparin, aspirin, and dipyridamole. Adequate anticoagulation is more difficult in children. However, 71% of the patients in our study survived long term. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  12. Patient-ventilator synchrony in Neurally Adjusted Ventilatory Assist (NAVA) and Pressure Support Ventilation (PSV): a prospective observational study.

    Science.gov (United States)

    Yonis, Hodane; Crognier, Laure; Conil, Jean-Marie; Serres, Isabelle; Rouget, Antoine; Virtos, Marie; Cougot, Pierre; Minville, Vincent; Fourcade, Olivier; Georges, Bernard

    2015-08-08

    Weaning from mechanical ventilation is associated with the presence of asynchronies between the patient and the ventilator. The main objective of the present study was to demonstrate a decrease in the total number of patient-ventilator asynchronies in invasively ventilated patients for whom difficulty in weaning is expected by comparing neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) ventilatory modes. We performed a prospective, non-randomized, non-interventional, single-center study. Thirty patients were included in the study. Each patient included in the study benefited in an unpredictable way from both modes of ventilation, NAVA or PSV. Patients were successively ventilated for 23 h in NAVA or in PSV, and then they were ventilated for another 23 h in the other mode. Demographic, biological and ventilatory data were collected during this period. The two modes of ventilatory support were compared using the non-parametric Wilcoxon test after checking for normal distribution by the Kolmogorov-Smirnov test. The groups were compared using the chi-square test. The median level of support was 12.5 cmH2O (4-20 cmH2O) in PSV and 0.8 cmH2O/μvolts (0.2-3 cmH2O/μvolts) in NAVA. The total number of asynchronies per minute in NAVA was lower than that in PSV (0.46 vs 1, p PSV (1.73 vs 3.36, p PSV (0.19 vs 0.71, p = 0.038). However, there was a higher percentage of double triggering in NAVA compared with PSV (0.76 vs 0.71, p = 0.046). The total number of asynchronies in NAVA is lower than that in PSV. This finding reflects improved patient-ventilator interaction in NAVA compared with the PSV mode, which is consistent with previous studies. Our study is the first to analyze patient-ventilator asynchronies in NAVA and PSV on such an important duration. The decrease in the number of asynchronies in NAVA is due to reduced ineffective efforts and auto-triggering.

  13. Neurally adjusted ventilatory assist as an alternative to pressure support ventilation in adults: a French multicentre randomized trial.

    Science.gov (United States)

    Demoule, A; Clavel, M; Rolland-Debord, C; Perbet, S; Terzi, N; Kouatchet, A; Wallet, F; Roze, H; Vargas, F; Guerin, C; Dellamonica, J; Jaber, S; Brochard, L; Similowski, T

    2016-11-01

    Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that tailors the level of assistance delivered by the ventilator to the electromyographic activity of the diaphragm. The objective of this study was to compare NAVA and pressure support ventilation (PSV) in the early phase of weaning from mechanical ventilation. A multicentre randomized controlled trial of 128 intubated adults recovering from acute respiratory failure was conducted in 11 intensive care units. Patients were randomly assigned to NAVA or PSV. The primary outcome was the probability of remaining in a partial ventilatory mode (either NAVA or PSV) throughout the first 48 h without any return to assist-control ventilation. Secondary outcomes included asynchrony index, ventilator-free days and mortality. In the NAVA and PSV groups respectively, the proportion of patients remaining in partial ventilatory mode throughout the first 48 h was 67.2 vs. 63.3 % (P = 0.66), the asynchrony index was 14.7 vs. 26.7 % (P < 0.001), the ventilator-free days at day 7 were 1.0 day [1.0-4.0] vs. 0.0 days [0.0-1.0] (P < 0.01), the ventilator-free days at day 28 were 21 days [4-25] vs. 17 days [0-23] (P = 0.12), the day-28 mortality rate was 15.0 vs. 22.7 % (P = 0.21) and the rate of use of post-extubation noninvasive mechanical ventilation was 43.5 vs. 66.6 % (P < 0.01). NAVA is safe and feasible over a prolonged period of time but does not increase the probability of remaining in a partial ventilatory mode. However, NAVA decreases patient-ventilator asynchrony and is associated with less frequent application of post-extubation noninvasive mechanical ventilation. clinicaltrials.gov Identifier: NCT02018666.

  14. The use of artificial neural networks in decision support in cancer: a systematic review.

    Science.gov (United States)

    Lisboa, Paulo J; Taktak, Azzam F G

    2006-05-01

    Artificial neural networks have featured in a wide range of medical journals, often with promising results. This paper reports on a systematic review that was conducted to assess the benefit of artificial neural networks (ANNs) as decision making tools in the field of cancer. The number of clinical trials (CTs) and randomised controlled trials (RCTs) involving the use of ANNs in diagnosis and prognosis increased from 1 to 38 in the last decade. However, out of 396 studies involving the use of ANNs in cancer, only 27 were either CTs or RCTs. Out of these trials, 21 showed an increase in benefit to healthcare provision and 6 did not. None of these studies however showed a decrease in benefit. This paper reviews the clinical fields where neural network methods figure most prominently, the main algorithms featured, methodologies for model selection and the need for rigorous evaluation of results.

  15. Neural mechanisms of selective exposure: an EEG study on the processing of decision-consistent and inconsistent information.

    Science.gov (United States)

    Fischer, Peter; Reinweber, Matthias; Vogrincic, Claudia; Schäfer, Axel; Schienle, Anne; Volberg, Gregor

    2013-01-01

    Decision makers tend to prefer decision-consistent information and/or neglect decision-inconsistent information (selective exposure). In the present EEG study the neural mechanisms of the classic selective exposure effect were examined by investigating oscillatory brain responses to consistent vs. inconsistent information. Twenty participants made an economic decision and subsequently were exposed to 45 consistent and 45 inconsistent images concerning their decision. EEG was recorded from 31 electrodes and differences between oscillatory brain responses towards consistent and inconsistent information were examined. The main result was an increase of induced theta power (5-8Hz, 0-0.7s) in the consistent compared to the inconsistent condition at right temporo-parietal electrodes, as well as a corresponding increase of evoked theta power at frontal electrodes. Since theta oscillations are often observed during memory formation, we conclude that decision-consistent information triggers memory formation, whereas decision-inconsistent information seems not to do so. This finding supports the classic motivational perspective of Leon Festinger on the selective exposure effect. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. In search for the neural mechanisms of individual development: behavior-driven differential Hebbian learning

    Directory of Open Access Journals (Sweden)

    Ralf eDer

    2016-01-01

    Full Text Available When Donald Hebb published his 1949 book ``The Organization of Behavior'' he opened a new way of thinking in theoretical neuroscience which, in retrospective, is very close to contemporary ideas in self-organization. His metaphor of ``wiring'' together what ``fires together'' matches very closely the commonparadigm that global organization can derive from simple local rules. While ingenious at his time and inspiring the research over decades, the results still fall short of the expectations. For instance,unsupervised as they are, such neural mechanisms should be able to explain and realize the self-organizedacquisition of sensorimotor competencies. This paper proposes a new synaptic law which replaces Hebb's original metaphor by that of ``chaining together'' what ``changes together''. Starting from differential Hebbian learning,the new rule grounds the behavior of the agent directly in the internal synaptic dynamics.Therefore, one may call this a behavior-driven synaptic plasticity.Neurorobotics is an ideal testing ground for this new, unsupervised learning rule. This paper focuses on the close coupling between body, control, and environmentin challenging physical settings. The examples demonstrate how the new synaptic mechanism induces a self-determined ``search and converge'' strategy in behavior space, generating spontaneously a variety of sensorimotor competencies. The emerging behavior patterns are qualified by involving body and environment inan irreducible conjunction with the internal mechanism.The results may not only be of immediate interest for the further development of embodied intelligence.They also offer a new view on the role of self-learning processes in natural evolutionand in the brain.Videos and further details may be found under url{http://robot.informatik.uni-leipzig.de/research/supplementary/NeuroAutonomy/}.

  17. Romantic love: an fMRI study of a neural mechanism for mate choice.

    Science.gov (United States)

    Fisher, Helen; Aron, Arthur; Brown, Lucy L

    2005-12-05

    Scientists have described myriad traits in mammalian and avian species that evolved to attract mates. But the brain mechanisms by which conspecifics become attracted to these traits is largely unknown. Yet mammals and birds express mate preferences and make mate choices, and data suggest that this "attraction system" is associated with the dopaminergic reward system. It has been proposed that intense romantic love, a cross-cultural universal, is a developed form of this attraction system. To determine the neural mechanisms associated with romantic love we used functional magnetic resonance imaging (fMRI) and studied 17 people who were intensely "in love" (Aron et al. [2005] J Neurophysiol 94:327-337). Activation specific to the beloved occurred in the right ventral tegmental area and right caudate nucleus, dopamine-rich areas associated with mammalian reward and motivation. These and other results suggest that dopaminergic reward pathways contribute to the "general arousal" component of romantic love; romantic love is primarily a motivation system, rather than an emotion; this drive is distinct from the sex drive; romantic love changes across time; and romantic love shares biobehavioral similarities with mammalian attraction. We propose that this attraction mechanism evolved to enable individuals to focus their mating energy on specific others, thereby conserving energy and facilitating mate choice-a primary aspect of reproduction. Last, the corticostriate system, with its potential for combining diverse cortical information with reward signals, is an excellent anatomical substrate for the complex factors contributing to romantic love and mate choice. (c) 2005 Wiley-Liss, Inc.

  18. A Cooperative Control Method for Fully Mechanized Mining Machines Based on Fuzzy Logic Theory and Neural Networks

    Directory of Open Access Journals (Sweden)

    Chao Tan

    2015-01-01

    Full Text Available In a fully mechanized mining face, the coordinated control of coal mining machines has a significant promoting effect to perfect the mining environment and improve the efficiency of coal production and has become a research focus all over the world. In this paper, a cooperative control method based on the integration of fuzzy logic theory and neural networks was proposed. The improved Elman neural network (ENN through a threshold strategy was presented to predict the running parameters of coal mining machines. On the basis of coupling analysis of coal mining machines, the expert knowledge base of scraper conveyor was established based on fuzzy logic theory. Furthermore, the probabilistic neural network (PNN was applied to evaluate the running status of scraper conveyor, and the cooperative control flow was designed and analyzed. Finally, a simulation example was provided and the comparison results illustrated that the proposed method was feasible and superior to the manual control.

  19. [Protective effects and its mechanism on neural cells after folic acid intervention in preeclampsia rat model].

    Science.gov (United States)

    Wang, Jun; Ge, Jing; Yang, Li-na; Xue, Dan; Li, Ju

    2011-08-01

    To investigate protective effects and mechanism of folic acid on brain neural cells in preeclampsia rat model. Adult pregnant Wistar rats were randomly divided into 4 groups (n = 10 in each group). Rats in model group were injected intraperitoneally with homocysteine (Hcy, 200 mg × kg(-1) × d(-1)) daily and were injected subcutaneously every other day with monosodium glutamate (MSG, 1 g × kg(-1)· 48 h(-1)) from the 10th day of pregnancy to establish the model of preeclampsia. Low-dose folic acid (low dose group 10 mg × kg(-1) × d(-1)) and high-dose folic acid (high dose group 20 mg × kg(-1) × d(-1)) were given intragastric administration with folic acid tablets dissolved in saline daily at the same time of establishing model. Rats in control group were injected or intragastric administration with the same dose of saline as above up to the 20th day of pregnancy. Brain tissue was fixed on the 20th day of pregnancy, so was that plasma folic acid was measured with automatic electro-chemiluminescence. Rats' neural nerve cells apoptosis was observed with tunel. Nuclear factor (NF)-κB activation was observed with immunohistochemical staining. bcl-2 mRNA and protein expression changes were observed by using reverse transcription (RT)-PCR and western blot. (1) Plasma folate concentrations were (39.5 ± 3.4) nmol/L in low dose group and (40.1 ± 5.4) nmol/L in high dose group, which were all significantly higher than (26.9 ± 6.7) nmol/L in model group (P 0.05); (2) Apoptosis cell were 48.2 ± 9.1 in low dose group and 44.7 ± 8.3 in high dose group, which were significantly lower than 75.8 ± 10.1 in model group (P apoptosis cell in low dose and high dose group did not show significant difference (P > 0.05); (3) NF-κB activation were 48 ± 9 in low dose group and 45 ± 8 in high dose group, which were significantly lower 76 ± 10 in model group (P 0.05); (4) bcl-2 mRNA and protein expression were 0.98 ± 0.49 and 0.89 ± 0.52 in low dose group and 0.95 ± 0.38 and

  20. Neural mechanisms of auditory categorization: from across brain areas to within local microcircuits

    Directory of Open Access Journals (Sweden)

    Joji eTsunada

    2014-06-01

    Full Text Available Categorization enables listeners to efficiently encode and respond to auditory stimuli. Behavioral evidence for auditory categorization has been well documented across a broad range of human and non-human animal species. Moreover, neural correlates of auditory categorization have been documented in a variety of different brain regions in the ventral auditory pathway, which is thought to underlie auditory-object processing and auditory perception. Here, we review and discuss how neural representations of auditory categories are transformed across different scales of neural organization in the ventral auditory pathway: from across different brain areas to within local microcircuits. We propose different neural transformations across different scales of neural organization in auditory categorization. Along the ascending auditory system in the ventral pathway, there is a progression in the encoding of categories from simple acoustic categories to categories for abstract information. On the other hand, in local microcircuits, different classes of neurons differentially compute categorical information.

  1. Neural mechanisms of reward processing associated with depression-related personality traits.

    Science.gov (United States)

    Umemoto, Akina; Holroyd, Clay B

    2017-07-01

    Although impaired reward processing in depression has been well-documented, the exact nature of that deficit remains poorly understood. To investigate the link between depression and the neural mechanisms of reward processing, we examined individual differences in personality. We recorded the electroencephalogram from healthy college students engaged in a probabilistic reinforcement learning task. Participants also completed several personality questionnaires that assessed traits related to reward sensitivity, motivation, and depression. We examined whether behavioral measures of reward learning and event-related potential components related to outcome processing and reward anticipation-namely, the cue and feedback-related reward positivity (RewP) and the stimulus preceding negativity (SPN)-would link these personality traits to depression. Participants who scored high in reward sensitivity produced a relatively larger feedback-RewP. By contrast, participants who scored high in depression learned the contingencies for infrequently rewarded cue-response combinations relatively poorly, exhibited a larger SPN, and produced a smaller feedback-RewP, especially to outcomes following cue-response combinations that were frequently rewarded. These results point to a primary deficit in reward valuation in individuals who score high in depression, with secondary consequences that impact reward learning and anticipation. Despite recent evidence arguing for an anticipatory deficit in depression, impaired reward valuation as a primary deficit should be further examined in clinical samples. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  2. Seeing is believing: neural mechanisms of action-perception are biased by team membership.

    Science.gov (United States)

    Molenberghs, Pascal; Halász, Veronika; Mattingley, Jason B; Vanman, Eric J; Cunnington, Ross

    2013-09-01

    Group identification can lead to a biased view of the world in favor of "in-group" members. Studying the brain processes that underlie such in-group biases is important for a wider understanding of the potential influence of social factors on basic perceptual processes. In this study, we used functional magnetic resonance imaging (fMRI) to investigate how people perceive the actions of in-group and out-group members, and how their biased view in favor of own team members manifests itself in the brain. We divided participants into two teams and had them judge the relative speeds of hand actions performed by an in-group and an out-group member in a competitive situation. Participants judged hand actions performed by in-group members as being faster than those of out-group members, even when the two actions were performed at physically identical speeds. In an additional fMRI experiment, we showed that, contrary to common belief, such skewed impressions arise from a subtle bias in perception and associated brain activity rather than decision-making processes, and that this bias develops rapidly and involuntarily as a consequence of group affiliation. Our findings suggest that the neural mechanisms that underlie human perception are shaped by social context. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

  3. Modulatory effect of romantic love on value estimation and its neural mechanism.

    Science.gov (United States)

    Wang, Ying; Zhang, Yuting; Chen, Ying; Jing, Fang; Wang, Zhenni; Hao, Yaru; Yang, Lizhuang; Liu, Ying; Zhou, Yifeng; Zhang, Xiaochu

    2016-03-23

    Any decision that is based upon personal preferences utilizes subjective values; however, for objectively equivalent items, whether romantic love modulates subjective value as well as the neural mechanism of this process remains unknown. In this functional MRI study, 30 items with equivalent value were first selected and assigned into three groups, and participants were trained to associate each group of items with their lover, a familiar person, or an unfamiliar person. Thereafter, the participant rated the values of the items during functional MRI scanning, after which they performed a post-test of memory of the associations. Behavioral results demonstrated that, although the items were well remembered, the items that were associated with the lover were rated significantly higher than the other images. Furthermore, we found higher activation related to the items associated with the lover than for those associated with a familiar person or an unfamiliar person in the striatum and the medial prefrontal cortex (related to cognitive control process). Finally, a morphometric analysis demonstrated that gray matter thickness in the striatum was positively associated with gray matter thickness in the medial prefrontal cortex but negatively correlated with the activation that was elicited by the items that were associated with the lover in the same brain area. Our results suggest that the romantic love-related brain region (the striatum) may modulate subjective value through the striatal-prefrontal pathway, further suggesting a potential bottom-up (control impulsivity) process.

  4. Early Life Stress and the Anxious Brain: Evidence for A Neural Mechanism Linking Childhood Emotional Maltreatment to Anxiety in Adulthood

    Science.gov (United States)

    Fonzo, Gregory A.; Ramsawh, Holly J.; Flagan, Taru M.; Simmons, Alan N.; Sullivan, Sarah G.; Allard, Carolyn B.; Paulus, Martin P.; Stein, Murray B.

    2016-01-01

    Background Childhood emotional maltreatment (CEM) increases likelihood of developing an anxiety disorder in adulthood, but the neural processes underlying conferment of this risk have not been established. Here, we test the potential for neuroimaging the adult brain to inform understanding of the mechanism linking CEM to adult anxiety symptoms. Methods One hundred eighty-two adults (148 females, 34 males) with a normal-to-clinical range of anxiety symptoms underwent structural and functional magnetic resonance imaging while completing an emotion-processing paradigm with facial expressions of fear, anger, and happiness. Participants completed self-report measures of CEM and current anxiety symptoms. Voxelwise mediation analyses on gray matter volumes and activation to each emotion condition were used to identify candidate brain mechanisms relating CEM to anxiety in adulthood. Results During processing of fear and anger faces, greater amygdala and less right dorsolateral prefrontal (dlPFC) activation partially mediated the positive relationship between CEM and anxiety symptoms. Greater right posterior insula activation to fear also partially mediated this relationship, as did greater ventral anterior cingulate (ACC) and less dorsal ACC activation to anger. Responses to happy faces in these regions did not mediate the CEM-anxiety relationship. Smaller right dlPFC gray matter volumes also partially mediated the CEM-anxiety relationship. Conclusions Activation patterns of the adult brain demonstrate the potential to inform mechanistic accounts of the CEM conferment of anxiety symptoms. Results support the hypothesis that exaggerated limbic activation to negative valence facial emotions links CEM to anxiety symptoms, which may be consequent to a breakdown of cortical regulatory processes. PMID:26670947

  5. Neural mechanisms of the influence of popularity on adolescent ratings of music.

    Science.gov (United States)

    Berns, Gregory S; Capra, C Monica; Moore, Sara; Noussair, Charles

    2010-02-01

    It is well-known that social influences affect consumption decisions. We used functional magnetic resonance imaging (fMRI) to elucidate the neural mechanisms associated with social influence with regard to a common consumer good: music. Our study population was adolescents, age 12-17. Music is a common purchase in this age group, and it is widely believed that adolescent behavior is influenced by perceptions of popularity in their reference group. Using 15-s clips of songs from MySpace.com, we obtained behavioral measures of preferences and neurobiological responses to the songs. The data were gathered with, and without, the overall popularity of the song revealed. Song popularity had a significant effect on the participants' likability ratings of the songs. fMRI results showed a strong correlation between the participants' rating and activity in the caudate nucleus, a region previously implicated in reward-driven actions. The tendency to change one's evaluation of a song was positively correlated with activation in the anterior insula and anterior cingulate, two regions that are associated with physiological arousal and negative affective states. Sensitivity to popularity was linked to lower activation levels in the middle temporal gyrus, suggesting a lower depth of musical semantic processing. Our results suggest that a principal mechanism whereby popularity ratings affect consumer choice is through the anxiety generated by the mismatch between one's own preferences and others'. This mismatch anxiety motivates people to switch their choices in the direction of the consensus. Our data suggest that this is a major force behind the conformity observed in music tastes in some teenagers. Copyright (c) 2009 Elsevier Inc. All rights reserved.

  6. Anti-Inflammatory Mechanism of Neural Stem Cell Transplantation in Spinal Cord Injury.

    Science.gov (United States)

    Cheng, Zhijian; Zhu, Wen; Cao, Kai; Wu, Fei; Li, Jin; Wang, Guoyu; Li, Haopen; Lu, Ming; Ren, Yi; He, Xijing

    2016-08-23

    Neural stem cell (NSC) transplantation has been proposed to promote functional recovery after spinal cord injury. However, a detailed understanding of the mechanisms of how NSCs exert their therapeutic plasticity is lacking. We transplanted mouse NSCs into the injured spinal cord seven days after SCI, and the Basso Mouse Scale (BMS) score was performed to assess locomotor function. The anti-inflammatory effects of NSC transplantation was analyzed by immunofluorescence staining of neutrophil and macrophages and the detection of mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and interleukin-12 (IL-12). Furthermore, bone marrow-derived macrophages (BMDMs) were co-cultured with NSCs and followed by analyzing the mRNA levels of inducible nitric oxide synthase (iNOS), TNF-α, IL-1β, IL-6 and IL-10 with quantitative real-time PCR. The production of TNF-α and IL-1β by BMDMs was examined using the enzyme-linked immunosorbent assay (ELISA). Transplanted NSCs had significantly increased BMS scores (p transplantation significantly reduced the number of neutrophils and iNOS+/Mac-2+ cells at the epicenter of the injured area (p transplantation group were significantly decreased compared to the control group. Furthermore, NSCs inhibited the iNOS expression of BMDMs and the release of inflammatory factors by macrophages in vitro (p transplantation could modulate SCI-induced inflammatory responses and enhance neurological function after SCI via reducing M1 macrophage activation and infiltrating neutrophils. Thus, this study provides a new insight into the mechanisms responsible for the anti-inflammatory effect of NSC transplantation after SCI.

  7. Neural Plasticity in Speech Acquisition and Learning

    Science.gov (United States)

    Zhang, Yang; Wang, Yue

    2007-01-01

    Neural plasticity in speech acquisition and learning is concerned with the timeline trajectory and the mechanisms of experience-driven changes in the neural circuits that support or disrupt linguistic function. In this selective review, we discuss the role of phonetic learning in language acquisition, the "critical period" of learning, the agents…

  8. Neural bases of accented speech perception

    OpenAIRE

    Patti eAdank; Nuttall, Helen E.; Briony eBanks; Dan eKennedy-Higgins

    2015-01-01

    The recognition of unfamiliar regional and foreign accents represents a challenging task for the speech perception system (Adank, Evans, Stuart-Smith, & Scott, 2009; Floccia, Goslin, Girard, & Konopczynski, 2006). Despite the frequency with which we encounter such accents, the neural mechanisms supporting successful perception of accented speech are poorly understood. Nonetheless, candidate neural substrates involved in processing speech in challenging listening conditions, including accented...

  9. The neural development of conditional reasoning in children: Different mechanisms for assessing the logical validity and likelihood of conclusions.

    Science.gov (United States)

    Schwartz, Flora; Epinat-Duclos, Justine; Léone, Jessica; Prado, Jérôme

    2017-09-19

    Scientific and mathematical thinking relies on the ability to evaluate whether conclusions drawn from conditional (if-then) arguments are logically valid. Yet, the neural development of this ability -- termed deductive reasoning -- is largely unknown. Here we aimed to identify the neural mechanisms that underlie the emergence of deductive reasoning with conditional rules in children. We further tested whether these mechanisms have their roots in the neural mechanisms involved in judging the likelihood of conclusions. In a functional Magnetic Resonance Imaging (fMRI) scanner, 8- to 13-year-olds were presented with causal conditional problems such as "If a baby is hungry then he will start crying; The baby is crying; Is the baby hungry?". In Validity trials, children were asked to indicate whether the conclusion followed out of necessity from the premises. In Likelihood trials, they indicated the degree of likelihood of the conclusion. We found that children who made accurate judgments of logical validity (as compared to those who did not) exhibited enhanced activity in left and medial frontal regions. In contrast, differences in likelihood ratings between children were related to differences of activity in right frontal and bilateral parietal regions. There was no overlap between the brain regions underlying validity and likelihood judgments. Therefore, our results suggest that the ability to evaluate the logical validity of conditional arguments emerges from brain mechanisms that qualitatively differ from those involved in evaluating the likelihood of these arguments in children. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Classification of bifurcations regions in IVOCT images using support vector machine and artificial neural network models

    Science.gov (United States)

    Porto, C. D. N.; Costa Filho, C. F. F.; Macedo, M. M. G.; Gutierrez, M. A.; Costa, M. G. F.

    2017-03-01

    Studies in intravascular optical coherence tomography (IV-OCT) have demonstrated the importance of coronary bifurcation regions in intravascular medical imaging analysis, as plaques are more likely to accumulate in this region leading to coronary disease. A typical IV-OCT pullback acquires hundreds of frames, thus developing an automated tool to classify the OCT frames as bifurcation or non-bifurcation can be an important step to speed up OCT pullbacks analysis and assist automated methods for atherosclerotic plaque quantification. In this work, we evaluate the performance of two state-of-the-art classifiers, SVM and Neural Networks in the bifurcation classification task. The study included IV-OCT frames from 9 patients. In order to improve classification performance, we trained and tested the SVM with different parameters by means of a grid search and different stop criteria were applied to the Neural Network classifier: mean square error, early stop and regularization. Different sets of features were tested, using feature selection techniques: PCA, LDA and scalar feature selection with correlation. Training and test were performed in sets with a maximum of 1460 OCT frames. We quantified our results in terms of false positive rate, true positive rate, accuracy, specificity, precision, false alarm, f-measure and area under ROC curve. Neural networks obtained the best classification accuracy, 98.83%, overcoming the results found in literature. Our methods appear to offer a robust and reliable automated classification of OCT frames that might assist physicians indicating potential frames to analyze. Methods for improving neural networks generalization have increased the classification performance.

  11. Synchronized mechanical ventilation for respiratory support in newborn infants.

    Science.gov (United States)

    Greenough, Anne; Murthy, Vadivelam; Milner, Anthony D; Rossor, Thomas E; Sundaresan, Adesh

    2016-08-19

    During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen

  12. QSAR models for prediction study of HIV protease inhibitors using support vector machines, neural networks and multiple linear regression

    Directory of Open Access Journals (Sweden)

    Rachid Darnag

    2017-02-01

    Full Text Available Support vector machines (SVM represent one of the most promising Machine Learning (ML tools that can be applied to develop a predictive quantitative structure–activity relationship (QSAR models using molecular descriptors. Multiple linear regression (MLR and artificial neural networks (ANNs were also utilized to construct quantitative linear and non linear models to compare with the results obtained by SVM. The prediction results are in good agreement with the experimental value of HIV activity; also, the results reveal the superiority of the SVM over MLR and ANN model. The contribution of each descriptor to the structure–activity relationships was evaluated.

  13. Prediction of Tourism Demand in Iran by Using Artificial Neural Network (ANN and Supporting Vector Machine (SVR

    Directory of Open Access Journals (Sweden)

    Seyedehelham Sadatiseyedmahalleh

    2016-02-01

    Full Text Available This research examines and proves this effectiveness connected with artificial neural networks (ANNs as an alternative approach to the use of Support Vector Machine (SVR in the tourism research. This method can be used for the tourism industry to define the turism’s demands in Iran. The outcome reveals the use of ANNs in tourism research might result in better quotations when it comes to prediction bias and accuracy. Even more applications of ANNs in the context of tourism demand evaluation is needed to establish and validate the effects.

  14. A prospective crossover comparison of neurally adjusted ventilatory assist and pressure-support ventilation in a pediatric and neonatal intensive care unit population.

    LENUS (Irish Health Repository)

    Breatnach, Cormac

    2012-02-01

    OBJECTIVE: To compare neurally adjusted ventilatory assist ventilation with pressure-support ventilation. DESIGN: Prospective, crossover comparison study. SETTING: Tertiary care pediatric and neonatal intensive care unit. PATIENTS: Sixteen ventilated infants and children: mean age = 9.7 months (range = 2 days-4 yrs) and mean weight = 6.2 kg (range = 2.4-13.7kg). INTERVENTIONS: A modified nasogastric tube was inserted and correct positioning was confirmed. Patients were ventilated in pressure-support mode with a pneumatic trigger for a 30-min period and then in neurally adjusted ventilatory assist mode for up to 4 hrs. MEASUREMENTS AND MAIN RESULTS: Data collected for comparison included activating trigger (neural vs. pneumatic), peak and mean airway pressures, expired minute and tidal volumes, heart rate, respiratory rate, pulse oximetry, end-tidal CO2 and arterial blood gases. Synchrony was improved in neurally adjusted ventilatory assist mode with 65% (+\\/-21%) of breaths triggered neurally vs. 35% pneumatically (p < .001) and 85% (+\\/-8%) of breaths cycled-off neurally vs. 15% pneumatically (p = .0001). The peak airway pressure in neurally adjusted ventilatory assist mode was significantly lower than in pressure-support mode with a 28% decrease in pressure after 30 mins (p = .003) and 32% decrease after 3 hrs (p < .001). Mean airway pressure was reduced by 11% at 30 mins (p = .13) and 9% at 3 hrs (p = .31) in neurally adjusted ventilatory assist mode although this did not reach statistical significance. Patient hemodynamics and gas exchange remained stable for the study period. No adverse patient events or device effects were noted. CONCLUSIONS: In a neonatal and pediatric intensive care unit population, ventilation in neurally adjusted ventilatory assist mode was associated with improved patient-ventilator synchrony and lower peak airway pressure when compared with pressure-support ventilation with a pneumatic trigger. Ventilating patients in this new mode

  15. Neural Operant Conditioning as a Core Mechanism of Brain-Machine Interface Control

    Directory of Open Access Journals (Sweden)

    Yoshio Sakurai

    2016-08-01

    Full Text Available The process of changing the neuronal activity of the brain to acquire rewards in a broad sense is essential for utilizing brain-machine interfaces (BMIs, which is essentially operant conditioning of neuronal activity. Currently, this is also known as neural biofeedback, and it is often referred to as neurofeedback when human brain activity is targeted. In this review, we first illustrate biofeedback and operant conditioning, which are methodological background elements in neural operant conditioning. Then, we introduce research models of neural operant conditioning in animal experiments and demonstrate that it is possible to change the firing frequency and synchronous firing of local neuronal populations in a short time period. We also debate the possibility of the application of neural operant conditioning and its contribution to BMIs.

  16. Artificial Neural Networks for Nonlinear Dynamic Response Simulation in Mechanical Systems

    DEFF Research Database (Denmark)

    Christiansen, Niels Hørbye; Høgsberg, Jan Becker; Winther, Ole

    2011-01-01

    It is shown how artificial neural networks can be trained to predict dynamic response of a simple nonlinear structure. Data generated using a nonlinear finite element model of a simplified wind turbine is used to train a one layer artificial neural network. When trained properly the network is ab...... to perform accurate response prediction much faster than the corresponding finite element model. Initial result indicate a reduction in cpu time by two orders of magnitude.......It is shown how artificial neural networks can be trained to predict dynamic response of a simple nonlinear structure. Data generated using a nonlinear finite element model of a simplified wind turbine is used to train a one layer artificial neural network. When trained properly the network is able...

  17. Financial and clinical outcomes of extracorporeal mechanical support.

    Science.gov (United States)

    Chiu, Ryan; Pillado, Eric; Sareh, Sohail; De La Cruz, Kim; Shemin, Richard J; Benharash, Peyman

    2017-03-01

    Over the past decade, extracorporeal mechanical support (ECMO) has been increasingly utilized in respiratory failure and cardiogenic shock. There is a need for assessing clinical and financial outcomes of ECMO use. This study presents our institution's experience with veno-arterial ECMO (VA-ECMO) over a 9-year period. A retrospective review of our institution's ECMO database identified patients undergoing VA-ECMO between 2005 and 2013 (N = 150). Patients were assigned to four groups by indication: post-cardiotomy syndrome, cardiogenic shock requiring cardiopulmonary resuscitation (CPR), cardiogenic shock not requiring CPR, and respiratory failure. Hospital charges from administrative records were analyzed. Trend and correlation analyses were used to evaluate clinical and financial outcomes. Of the 150 patients meeting inclusion criteria, 28% required VA-ECMO for post-cardiotomy syndrome, 31.3% for cardiogenic shock with CPR, 35.3% for cadiogenic shock with no CPR, and 5.4% for respiratory failure. Mean duration on ECMO was 5.0 ± 3.4 days with a survival rate of 64% and no difference between the four groups (p = 0.40). ECMO-associated charges averaged $74,500 ± 61,400 per patient, 6% of total hospital charges. Subgroup analysis of cardiogenic shock patients revealed a nearly twofold increase in ECMO-related charges among patients who did not receive CPR (p = 0.04), as well as a trend toward improved survival (69.8% vs 51.1%, p = 0.06). In view of the variations in survival and costs in ECMO patients, further studies should aim to delineate patient populations that benefit from early initiation of ECMO. © 2017 Wiley Periodicals, Inc.

  18. Neural mechanisms of repetition priming of familiar and globally unfamiliar visual objects.

    Science.gov (United States)

    Soldan, Anja; Habeck, Christian; Gazes, Yunglin; Stern, Yaakov

    2010-07-09

    Functional magnetic resonance imaging (fMRI) studies have shown that repetition priming of visual objects is typically accompanied by a reduction in activity for repeated compared to new stimuli (repetition suppression). However, the spatial distribution and direction (suppression vs. enhancement) of neural repetition effects can depend on the pre-experimental familiarity of stimuli. The first goal of this study was to further probe the link between repetition priming and repetition suppression/enhancement for visual objects and how this link is affected by stimulus familiarity. A second goal was to examine whether priming of familiar and unfamiliar objects following a single stimulus repetition is supported by the same processes as priming following multiple repetitions within the same task. In this endeavor, we examined both between and within-subject correlations between priming and fMRI repetition effects for familiar and globally unfamiliar visual objects during the first and third repetitions of the stimuli. We included reaction time of individual trials as a linear regressor to identify brain regions whose repetition effects varied with response facilitation on a trial-by-trial basis. The results showed that repetition suppression in bilateral fusiform gyrus, was selectively correlated with priming of familiar objects that had been repeated once, likely reflecting facilitated perceptual processing or the sharpening of perceptual representations. Priming during the third repetition was correlated with repetition suppression in prefrontal and parietal areas for both familiar and unfamiliar stimuli, possibly reflecting a shift from top-down controlled to more automatic processing that occurs for both item types. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  19. Dissociated neural mechanisms for face detection and configural encoding: evidence from N170 and induced gamma-band oscillation effects.

    Science.gov (United States)

    Zion-Golumbic, Elana; Bentin, Shlomo

    2007-08-01

    Despite ample research, the structure and the functional characteristics of neural systems involved in human face processing are still a matter of active debate. Here we dissociated between a neural mechanism manifested by the face-sensitive N170 event-related potential effect and a mechanism manifested by induced electroencephalographic oscillations in the gamma band, which have been previously associated with the integration of individually coded features and activation of corresponding neural representations. The amplitude of the N170 was larger in the absence of the face contour but not affected by the configuration of inner components (ICs). Its latency was delayed by scrambling the configuration of the components as well as by the absence of the face contour. Unlike the N170, the amplitude of the induced gamma activity was sensitive to the configuration of ICs but insensitive to their presence within or outside a face contour. This pattern suggests a dual mechanism for early face processing, each utilizing different visual cues, which might indicate their respective roles in face processing. The N170 seems to be associated primarily with the detection and categorization of faces, whereas the gamma oscillations may be involved in the activation of their mental representation.

  20. Neural mechanisms for the effect of prior knowledge on audiovisual integration.

    Science.gov (United States)

    Liu, Qiang; Zhang, Ye; Campos, Jennifer L; Zhang, Qinglin; Sun, Hong-Jin

    2011-05-01

    Converging evidence indicates that prior knowledge plays an important role in multisensory integration. However, the neural mechanisms underlying the processes with which prior knowledge is integrated with current sensory information remains unknown. In this study, we measured event-related potentials (ERPs) while manipulating prior knowledge using a novel visual letter recognition task in which auditory information was always presented simultaneously. The color of the letters was assigned to a particular probability of being associated with audiovisual congruency (e.g., green=high probability (HP) and blue=low probability (LP)). Results demonstrate that this prior began affecting reaction times to the congruent audiovisual stimuli at about the 900th trial. Consequently, the ERP data was analyzed in two phases: the "early phase" (trial 900). The effects of prior knowledge were revealed through difference waveforms generated by subtracting the ERPs for the congruent audiovisual stimuli in the LP condition from those in the HP condition. A frontal-central probability effect (90-120 ms) was observed in the early phase. A right parietal-occipital probability effect (40-96 ms) and a frontal-central probability effect (170-200 ms) were observed in the late phase. The results suggest that during the initial acquisition of the knowledge about the probability of congruency, the brain assigned more attention to audiovisual stimuli for the LP condition. Following the acquisition of this prior knowledge, it was then used during early stages of visual processing and modulated the activity of multisensory cortical areas. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Neural mechanism of pupillary dilation elicited by electro-acupuncture stimulation in anesthetized rats.

    Science.gov (United States)

    Ohsawa, H; Yamaguchi, S; Ishimaru, H; Shimura, M; Sato, Y

    1997-06-06

    The neural mechanisms to reflex dilation elicited by electro-acupuncture stimulation were investigated in anesthetized rats. Two needles, with 160 microns diameter and about 5 mm apart, were inserted into the skin and underlying muscle of a hindpaw. Repetitive 20 Hz, 0.5 ms electrical pulses at various intensities were used for stimulation for 30s. The pupil size was magnified about 44 times via a microscope and was continuously recorded on a videotape. Electro-acupuncture stimulation at more than 0.5 up to 6 mA induced stimulus intensity-dependent pupil dilation. These responses were abolished by the severance of the sciatic and saphenous nerve of the stimulated hindlimb. Compound action potentials were recorded from the distal cut end of the tibial of a saphenous nerve following electro-acupuncture stimulation of the hindpaw. The mean threshold of the compound action potentials of the myelinated fibers in saphenous nerves was 0.18 mA, while that of unmyelinated fibers was 3.0 mA. The mean threshold of the compound action potentials of the myelinated fibers in the tibial nerve was 0.20 mA of unmyelinated fibers was 3.3 mA. Severance of bilateral trunks did not affect the response, while severance of the third cranial nerves abolished the responses. In conclusion, electro-acupuncture stimulation applied to the hindpaws of the anesthetized rats induced excitation of myelinated or of both myelinated and unmyelinated afferent fibers of the tibial and saphenous nerve, and involved a reflex response of pupil dilation through the third cranial parasympathetic efferent nerve.

  2. Building bridges between perceptual and economic decision-making: neural and computational mechanisms

    Directory of Open Access Journals (Sweden)

    Christopher eSummerfield

    2012-05-01

    Full Text Available Investigation into the neural and computational bases of decision-making has proceeded in two parallel but distinct streams. Perceptual decision making (PDM is concerned with how observers detect, discriminate and categorise noisy sensory information. Economic decision making (EDM explores how options are selected on the basis of their reinforcement history. Traditionally, the subfields of PDM and EDM have employed different paradigms, proposed different mechanistic models, explored different brain regions, disagreed about whether decisions approach optimality. Nevertheless, we argue that there is a common framework for understanding decisions made in both domains, under which an agent has to combine sensory information (what is the stimulus with value information (what is it worth. We review computational models of the decision process typically used in PDM, based around the idea that decisions involve a serial integration of evidence, and assess their applicability to decisions between good and gambles. Subsequently, we consider the contribution of three key brain regions – the parietal cortex, the basal ganglia, and the orbitofrontal cortex – to perceptual and economic decision-making, with a focus on the mechanisms by which sensory and reward information are integrated during choice. We find that although the parietal cortex is often implicated in the integration of sensory evidence, there is evidence for its role in encoding the expected value of a decision. Similarly, although much research has emphasised the role of the striatum and orbitofrontal cortex in value-guided choices, they may play an important role in categorisation of perceptual information. In conclusion, we consider how findings from the two fields might be brought together, in order to move towards a general framework for understanding decision-making in humans and other primates.

  3. A neural model for temporal order judgments and their active recalibration: a common mechanism for space and time?

    Directory of Open Access Journals (Sweden)

    Mingbo eCai

    2012-11-01

    Full Text Available When observers experience a constant delay between their motor actions and sensory feedback, their perception of the temporal order between actions and sensations adapt (Stetson et al., 2006a. We present here a novel neural model that can explain temporal order judgments (TOJs and their recalibration. Our model employs three ubiquitous features of neural systems: 1 information pooling, 2 opponent processing, and 3 synaptic scaling. Specifically, the model proposes that different populations of neurons encode different delays between motor-sensory events, the outputs of these populations feed into rivaling neural populations (encoding before and after, and the activity difference between these populations determines the perceptual judgment. As a consequence of synaptic scaling of input weights, motor acts which are consistently followed by delayed sensory feedback will cause the network to recalibrate its point of subjective simultaneity. The structure of our model raises the possibility that recalibration of TOJs is a temporal analogue to the motion aftereffect. In other words, identical neural mechanisms may be used to make perceptual determinations about both space and time. Our model captures behavioral recalibration results for different numbers of adapting trials and different adapting delays. In line with predictions of the model, we additionally demonstrate that temporal recalibration can last through time, in analogy to storage of the motion aftereffect.

  4. Neural mechanism of lmplicit and explicit memory retrieval: functional MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Heoung Keun; Jeong, Gwang Woo; Park, Tae Jin; Seo, Jeong Jin; Kim, Hyung Joong; Eun, Sung Jong; Chung, Tae Woong [Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2003-03-01

    To identify, using functional MR imaging, distinct cerebral centers and to evaluate the neural mechanism associated with implicit and explicit retrieval of words during conceptual processing. Seven healthy volunteers aged 21-25 (mean, 22) years underwent BOLD-based fMR imaging using a 1.5T signa horizon echospeed MR system. To activate the cerebral cortices, a series of tasks was performed as follows: the encoding of two-syllable words, and implicit and explicit retrieval of previously learned words during conceptual processing. The activation paradigm consisted of a cycle of alternating periods of 30 seconds of stimulation and 30 seconds of rest. Stimulation was accomplished by encoding eight two-syllable words and the retrieval of previously presented words, while the control condition was a white screen with a small fixed cross. During the tasks we acquired ten slices (6 mm slice thickness, 1 mm gap) parallel to the AC-PC line, and the resulting functional activation maps were reconstructed using a statistical parametric mapping program (SPM99). A comparison of activation ratios (percentages), based on the number of volunteers, showed that activation of Rhs-35, PoCiG-23 and ICiG-26{center_dot}30 was associated with explicit retrieval only; other brain areas were activated during the performance of both implicit and explicit retrieval tasks. Activation ratios were higher for explicit tasks than for implicit; in the cingulate gyrus and temporal lobe they were 30% and 10% greater, respectively. During explicit retrieval, a distinct brain activation index (percentage) was seen in the temporal, parietal, and occipital lobe and cingulate gyrus, and PrCeG-4, Pr/ PoCeG-43 in the frontal lobe. During implicit retrieval, on the other hand, activity was greater in the frontal lobe, including the areas of SCA-25, SFG/MFG-10, IFG-44{center_dot}45, OrbG-11{center_dot}47, SFG-6{center_dot}8 and MFG-9{center_dot}46. Overall, activation was lateralized mainly in the left

  5. Anti-Inflammatory Mechanism of Neural Stem Cell Transplantation in Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Zhijian Cheng

    2016-08-01

    Full Text Available Neural stem cell (NSC transplantation has been proposed to promote functional recovery after spinal cord injury. However, a detailed understanding of the mechanisms of how NSCs exert their therapeutic plasticity is lacking. We transplanted mouse NSCs into the injured spinal cord seven days after SCI, and the Basso Mouse Scale (BMS score was performed to assess locomotor function. The anti-inflammatory effects of NSC transplantation was analyzed by immunofluorescence staining of neutrophil and macrophages and the detection of mRNA levels of tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β, interleukin-6 (IL-6 and interleukin-12 (IL-12. Furthermore, bone marrow-derived macrophages (BMDMs were co-cultured with NSCs and followed by analyzing the mRNA levels of inducible nitric oxide synthase (iNOS, TNF-α, IL-1β, IL-6 and IL-10 with quantitative real-time PCR. The production of TNF-α and IL-1β by BMDMs was examined using the enzyme-linked immunosorbent assay (ELISA. Transplanted NSCs had significantly increased BMS scores (p < 0.05. Histological results showed that the grafted NSCs migrated from the injection site toward the injured area. NSCs transplantation significantly reduced the number of neutrophils and iNOS+/Mac-2+ cells at the epicenter of the injured area (p < 0.05. Meanwhile, mRNA levels of TNF-α, IL-1β, IL-6 and IL-12 in the NSCs transplantation group were significantly decreased compared to the control group. Furthermore, NSCs inhibited the iNOS expression of BMDMs and the release of inflammatory factors by macrophages in vitro (p < 0.05. These results suggest that NSC transplantation could modulate SCI-induced inflammatory responses and enhance neurological function after SCI via reducing M1 macrophage activation and infiltrating neutrophils. Thus, this study provides a new insight into the mechanisms responsible for the anti-inflammatory effect of NSC transplantation after SCI.

  6. Neural mechanisms influencing interlimb coordination during locomotion in humans: presynaptic modulation of forearm H-reflexes during leg cycling.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Nakajima

    Full Text Available Presynaptic inhibition of transmission between Ia afferent terminals and alpha motoneurons (Ia PSI is a major control mechanism associated with soleus H-reflex modulation during human locomotion. Rhythmic arm cycling suppresses soleus H-reflex amplitude by increasing segmental Ia PSI. There is a reciprocal organization in the human nervous system such that arm cycling modulates H-reflexes in leg muscles and leg cycling modulates H-reflexes in forearm muscles. However, comparatively little is known about mechanisms subserving the effects from leg to arm. Using a conditioning-test (C-T stimulation paradigm, the purpose of this study was to test the hypothesis that changes in Ia PSI underlie the modulation of H-reflexes in forearm flexor muscles during leg cycling. Subjects performed leg cycling and static activation while H-reflexes were evoked in forearm flexor muscles. H-reflexes were conditioned with either electrical stimuli to the radial nerve (to increase Ia PSI; C-T interval  = 20 ms or to the superficial radial (SR nerve (to reduce Ia PSI; C-T interval  = 37-47 ms. While stationary, H-reflex amplitudes were significantly suppressed by radial nerve conditioning and facilitated by SR nerve conditioning. Leg cycling suppressed H-reflex amplitudes and the amount of this suppression was increased with radial nerve conditioning. SR conditioning stimulation removed the suppression of H-reflex amplitude resulting from leg cycling. Interestingly, these effects and interactions on H-reflex amplitudes were observed with subthreshold conditioning stimulus intensities (radial n., ∼0.6×MT; SR n., ∼ perceptual threshold that did not have clear post synaptic effects. That is, did not evoke reflexes in the surface EMG of forearm flexor muscles. We conclude that the interaction between leg cycling and somatosensory conditioning of forearm H-reflex amplitudes is mediated by modulation of Ia PSI pathways. Overall our results support a

  7. A recoil resilient lumen support, design, fabrication and mechanical evaluation

    Science.gov (United States)

    Mehdizadeh, Arash; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi; Al-Sarawi, Said; Abbott, Derek

    2013-06-01

    Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5-7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5-11

  8. 78 FR 54967 - Rural Health Care Support Mechanism

    Science.gov (United States)

    2013-09-09

    ... conduct or sponsor a collection of information unless it displays a current, valid OMB Control Number. No... Skilled Nursing Facilities Pilot (SNF Pilot) to test how to support broadband connections for skilled nursing facilities. All the requirements herein are necessary to administer the Rural Health Care support...

  9. Interactive Simulations to Support Quantum Mechanics Instruction for Chemistry Students

    Science.gov (United States)

    Kohnle, Antje; Benfield, Cory; Hahner, Georg; Paetkau, Mark

    2017-01-01

    The QuVis Quantum Mechanics Visualization Project provides freely available research-based interactive simulations with accompanying activities for the teaching and learning of quantum mechanics across a wide range of topics and levels. This article gives an overview of some of the simulations and describes their use in an introductory physical…

  10. 5-HTTLPR polymorphism is linked to neural mechanisms of selective attention in preschoolers from lower socioeconomic status backgrounds

    Directory of Open Access Journals (Sweden)

    Elif Isbell

    2016-12-01

    Full Text Available While a growing body of research has identified experiential factors associated with differences in selective attention, relatively little is known about the contribution of genetic factors to the skill of sustained selective attention, especially in early childhood. Here, we assessed the association between the serotonin transporter linked polymorphic region (5-HTTLPR genotypes and the neural mechanisms of selective attention in young children from lower socioeconomic status (SES backgrounds. Event-related potentials (ERPs were recorded during a dichotic listening task from 121 children (76 females, aged 40–67 months, who were also genotyped for the short and long allele of 5-HTTLPR. The effect of selective attention was measured as the difference in ERP mean amplitudes elicited by identical probe stimuli embedded in stories when they were attended versus unattended. Compared to children homozygous for the long allele, children who carried at least one copy of the short allele showed larger effects of selective attention on neural processing. These findings link the short allele of the 5-HTTLPR to enhanced neural mechanisms of selective attention and lay the groundwork for future studies of gene-by-environment interactions in the context of key cognitive skills.

  11. Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering.

    Science.gov (United States)

    Lv, Zhijin; Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

    2018-01-01

    In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch's bearing capability is 1286.9 kN, and the CCC arch's ultimate bearing capability is 1072.4kN. Thus, the SQCC arch's bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and

  12. MECHANISMS OF DOMESTIC FOOD SUPPORT IN THE WTO

    Directory of Open Access Journals (Sweden)

    Марина Львовна Яшина

    2014-05-01

    Full Text Available After Russia has become a member of WTO it influenced on the position of native producers and requires some supporting action from the government.The purpose of this research is to offer opportunities to support the producers and agroprocessors on the terms of WTO.The scientific importance of this research consists in proving that Russian agriculture needs government support based on the nature of market economics and theUSexample as the world’s largest agricultural producer. Practical importance consists in exploring and improving specific events that are held inUlyanovskregion on the terms of WTO’s regulations.Problems of food security are considered from the position of the unity of theory and practice based on macroeconomic and microeconomic approaches. General scientific methods of cognition and traditional methods of economic analysis are used in the article.General results of the research: opportunities to support AIC on the terms of WTO are designated; particular qualities of government support for agro producers in the USA are analyzed; types and forms of supporting native producers and agroprocessors in Ulyanovsk region are considered. Conclusion of the need of improving support of AIC in the way as native food assistance is made.DOI: http://dx.doi.org/10.12731/2218-7405-2013-9-100

  13. Effect of enzymatic and mechanical methods of dissociation on neural progenitor cells derived from induced pluripotent stem cells.

    Science.gov (United States)

    Jager, Lindsey D; Canda, Claire-Marie A; Hall, Crystal A; Heilingoetter, Cassandra L; Huynh, Joann; Kwok, Susanna S; Kwon, Jin H; Richie, Jacob R; Jensen, Matthew B

    2016-03-01

    To determine the most effective method of dissociating neural stem and progenitor cells into a single-cell suspension. Induced pluripotent stem cells were differentiated toward the neural fate for 4 weeks before clusters were subjected to enzymatic (Accutase, trypsin, TrypLE, dispase, or DNase I) or mechanical (trituration with pipettes of varying size) or combined dissociation. Images of cells were analyzed for cluster size using ImageJ. Cells treated with the enzymes Accutase, TrypLE, or trypsin/EDTA, these enzymes followed by trituration, or a combination one of these enzymes followed by incubation with another enzyme, including DNase I, were more likely to be dissociated into a single-cell suspension. Cells treated with enzymes or combinations of methods were more likely to be dissociated into a single-cell suspension. Copyright © 2015 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  14. Mechanical Ventilation and Decision Support in Pediatric Intensive Care.

    Science.gov (United States)

    Newth, Christopher John L; Khemani, Robinder G; Jouvet, Philippe A; Sward, Katherine A

    2017-10-01

    Respiratory support is required in most children in the pediatric intensive care unit. Decision-support tools (paper or electronic) have been shown to improve the quality of medical care, reduce errors, and improve outcomes. Computers can assist clinicians by standardizing descriptors and procedures, consistently performing calculations, incorporating complex rules with patient data, and capturing relevant data. This article discusses computer decision-support tools to assist clinicians in making flexible but consistent, evidence-based decisions for equivalent patient states. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Nearest patch matching for color image segmentation supporting neural network classification in pulmonary tuberculosis identification

    Science.gov (United States)

    Rulaningtyas, Riries; Suksmono, Andriyan B.; Mengko, Tati L. R.; Saptawati, Putri

    2016-03-01

    Pulmonary tuberculosis is a deadly infectious disease which occurs in many countries in Asia and Africa. In Indonesia, many people with tuberculosis disease are examined in the community health center. Examination of pulmonary tuberculosis is done through sputum smear with Ziehl - Neelsen staining using conventional light microscope. The results of Ziehl - Neelsen staining will give effect to the appearance of tuberculosis (TB) bacteria in red color and sputum background in blue color. The first examination is to detect the presence of TB bacteria from its color, then from the morphology of the TB bacteria itself. The results of Ziehl - Neelsen staining in sputum smear give the complex color images, so that the clinicians have difficulty when doing slide examination manually because it is time consuming and needs highly training to detect the presence of TB bacteria accurately. The clinicians have heavy workload to examine many sputum smear slides from the patients. To assist the clinicians when reading the sputum smear slide, this research built computer aided diagnose with color image segmentation, feature extraction, and classification method. This research used K-means clustering with patch technique to segment digital sputum smear images which separated the TB bacteria images from the background images. This segmentation method gave the good accuracy 97.68%. Then, feature extraction based on geometrical shape of TB bacteria was applied to this research. The last step, this research used neural network with back propagation method to classify TB bacteria and non TB bacteria images in sputum slides. The classification result of neural network back propagation are learning time (42.69±0.02) second, the number of epoch 5000, error rate of learning 15%, learning accuracy (98.58±0.01)%, and test accuracy (96.54±0.02)%.

  16. Artificial Neural Network Test Support Development for the Space Shuttle PRCS Thrusters

    Science.gov (United States)

    Lehr, Mark E.

    2005-01-01

    A significant anomaly, Fuel Valve Pilot Seal Extrusion, is affecting the Shuttle Primary Reaction Control System (PRCS) Thrusters, and has caused 79 to fail. To help address this problem, a Shuttle PRCS Thruster Process Evaluation Team (TPET) was formed. The White Sands Test Facility (WSTF) and Boeing members of the TPET have identified many discrete valve current trace characteristics that are predictive of the problem. However, these are difficult and time consuming to identify and trend by manual analysis. Based on this exhaustive analysis over months, 22 thrusters previously delivered by the Depot were identified as high risk for flight failures. Although these had only recently been installed, they had to be removed from Shuttles OV103 and OV104 for reprocessing, by directive of the Shuttle Project Office. The resulting impact of the thruster removal, replacement, and valve replacement was significant (months of work and hundreds of thousands of dollars). Much of this could have been saved had the proposed Neural Network (NN) tool described in this paper been in place. In addition to the significant benefits to the Shuttle indicated above, the development and implementation of this type of testing will be the genesis for potential Quality improvements across many areas of WSTF test data analysis and will be shared with other NASA centers. Future tests can be designed to incorporate engineering experience via Artificial Neural Nets (ANN) into depot level acceptance of hardware. Additionally, results were shared with a NASA Engineering and Safety Center (NESC) Super Problem Response Team (SPRT). There was extensive interest voiced among many different personnel from several centers. There are potential spin-offs of this effort that can be directly applied to other data acquisition systems as well as vehicle health management for current and future flight vehicles.

  17. Cross-Coupled Eye Movement Supports Neural Origin of Pattern Strabismus

    Science.gov (United States)

    Ghasia, Fatema F.; Shaikh, Aasef G.; Jacobs, Jonathan; Walker, Mark F.

    2015-01-01

    Purpose. Pattern strabismus describes vertically incomitant horizontal strabismus. Conventional theories emphasized the role of orbital etiologies, such as abnormal fundus torsion and misaligned orbital pulleys as a cause of the pattern strabismus. Experiments in animal models, however, suggested the role of abnormal cross-connections between the neural circuits. We quantitatively assessed eye movements in patients with pattern strabismus with a goal to delineate the role of neural circuits versus orbital etiologies. Methods. We measured saccadic eye movements with high-precision video-oculography in 14 subjects with pattern strabismus, 5 with comitant strabismus, and 15 healthy controls. We assessed change in eye position in the direction orthogonal to that of the desired eye movement (cross-coupled responses). We used fundus photography to quantify the fundus torsion. Results. We found cross-coupling of saccades in all patients with pattern strabismus. The cross-coupled responses were in the same direction in both eyes, but larger in the nonviewing eye. All patients had clinically apparent inferior oblique overaction with abnormal excylotorsion. There was no correlation between the amount of the fundus torsion or the grade of oblique overaction and the severity of cross-coupling. The disconjugacy in the saccade direction and amplitude in pattern strabismics did not have characteristics predicted by clinically apparent inferior oblique overaction. Conclusions. Our results validated primate models of pattern strabismus in human patients. We found no correlation between ocular torsion or oblique overaction and cross-coupling. Therefore, we could not ascribe cross-coupling exclusively to the orbital etiology. Patients with pattern strabismus could have abnormalities in the saccade generators. PMID:26024072

  18. Lithium - an update on the mechanisms of action. Part two: neural ...

    African Journals Online (AJOL)

    ... has a complicated multitude of diverse effects in the human nervous system. This new data is helping us understand the neurobiology of bipolar disorder. The focus of this review will be to distil this new knowledge.This, the second of a two part review will focus principally on neural effects and neuroanatomical substrates.

  19. Mechanisms of Developmental Regression in Autism and the Broader Phenotype: A Neural Network Modeling Approach

    Science.gov (United States)

    Thomas, Michael S. C.; Knowland, Victoria C. P.; Karmiloff-Smith, Annette

    2011-01-01

    Loss of previously established behaviors in early childhood constitutes a markedly atypical developmental trajectory. It is found almost uniquely in autism and its cause is currently unknown (Baird et al., 2008). We present an artificial neural network model of developmental regression, exploring the hypothesis that regression is caused by…

  20. Comparable mechanisms for action and language: Neural systems behind intentions, goals and means

    NARCIS (Netherlands)

    Schie, H.T. van; Toni, I.; Bekkering, H.

    2006-01-01

    In this position paper we explore correspondence between neural systems for language and action starting from recent electrophysiological findings on the roles of posterior and frontal areas in goal-directed grasping actions. The paper compares the perceptual and motor organization for action and

  1. Neural cell adhesion molecule induces intracellular signaling via multiple mechanisms of Ca2+ homeostasis

    DEFF Research Database (Denmark)

    Kiryushko, Darya; Korshunova, Irina; Berezin, Vladimir

    2006-01-01

    The neural cell adhesion molecule (NCAM) plays a pivotal role in the development of the nervous system, promoting neuronal differentiation via homophilic (NCAM-NCAM) as well as heterophilic (NCAM-fibroblast growth factor receptor [FGFR]) interactions. NCAM-induced intracellular signaling has been...

  2. Bird brains and songs : Neural mechanisms of auditory memory and perception in zebra finches

    NARCIS (Netherlands)

    Gobes, S.M.H.

    2009-01-01

    Songbirds, such as zebra finches, learn their songs from a ‘tutor’ (usually the father), early in life. There are strong parallels between the behavioural, cognitive and neural processes that underlie vocal learning in humans and songbirds. In both cases there is a sensitive period for auditory

  3. Tympanal mechanics and neural responses in the ears of a noctuid moth.

    Science.gov (United States)

    ter Hofstede, Hannah M; Goerlitz, Holger R; Montealegre-Z, Fernando; Robert, Daniel; Holderied, Marc W

    2011-12-01

    Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement, not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold.

  4. Robust Template Decomposition without Weight Restriction for Cellular Neural Networks Implementing Arbitrary Boolean Functions Using Support Vector Classifiers

    Directory of Open Access Journals (Sweden)

    Yih-Lon Lin

    2013-01-01

    Full Text Available If the given Boolean function is linearly separable, a robust uncoupled cellular neural network can be designed as a maximal margin classifier. On the other hand, if the given Boolean function is linearly separable but has a small geometric margin or it is not linearly separable, a popular approach is to find a sequence of robust uncoupled cellular neural networks implementing the given Boolean function. In the past research works using this approach, the control template parameters and thresholds are restricted to assume only a given finite set of integers, and this is certainly unnecessary for the template design. In this study, we try to remove this restriction. Minterm- and maxterm-based decomposition algorithms utilizing the soft margin and maximal margin support vector classifiers are proposed to design a sequence of robust templates implementing an arbitrary Boolean function. Several illustrative examples are simulated to demonstrate the efficiency of the proposed method by comparing our results with those produced by other decomposition methods with restricted weights.

  5. Support mechanisms and risk: Implications on the Nordic electricity system

    DEFF Research Database (Denmark)

    Kitzing, Lena; Ravn, Hans

    2013-01-01

    a stochastic analysis for the Nordic electricity system by conducting simulations with the energy system model Balmorel and by applying the mean-standard deviation approach of modern portfolio theory to quantify risk implications of policy instruments for an exemplary offshore wind park. The analysis reveals...... that the two support policy schemes Feed-in Tariffs and Feed-in Premiums provide different risk-return relationships. In the investigated case, a Feed-in Premium scheme would require a 13% higher support level, because of a 6% higher exposure of investors to market risk. Our findings can help when designing...

  6. 77 FR 42185 - Rural Health Care Support Mechanism

    Science.gov (United States)

    2012-07-18

    ... Competition Bureau at (202) 418-1732 or TTY (202) 418-0484. SUPPLEMENTARY INFORMATION: This is a synopsis of... allowing the RHC Pilot networks to continue to bill and operate as a consortium would be more... Program.'' Geisinger Health Systems also states that ending Pilot Program support for HCPs on its network...

  7. 75 FR 48235 - Rural Health Care Universal Service Support Mechanism

    Science.gov (United States)

    2010-08-09

    ... nursing facilities, and renal dialysis centers. The Commission also proposes to eliminate the offset... facilities that provide services traditionally provided at hospitals, such as skilled nursing facilities and... prioritize funding requests for rural health care support to the extent demand exceeds the annual $400...

  8. Outcome of Long-Term Mechanical Ventilation Support in Children

    Directory of Open Access Journals (Sweden)

    Shao-Hsuan Hsia

    2012-10-01

    Conclusions: There are now more children on long-term MV support in Taiwan and most are in respiratory care wards in local hospitals. The shift in underlying diagnoses from pulmonary disease to neurogenic respiratory insufficiency affects hospitalization. The main cause of respiratory insufficiency is neurologic insult.

  9. Mechanical performance of implant-supported posterior crowns

    NARCIS (Netherlands)

    de Kok, P.; Kleverlaan, C.J.; de Jager, N.; Kuijs, R.; Feilzer, A.J.

    2015-01-01

    Statement of problem The fracture of implant-supported restorations, especially of the veneering layer, is a common problem in dentistry. Monolithic ceramic or resin restorations might help solve this problem. Purpose The purpose of this in vitro study was to obtain additional insight into the risk

  10. Clinical assessment of auto-positive end-expiratory pressure by diaphragmatic electrical activity during pressure support and neurally adjusted ventilatory assist.

    Science.gov (United States)

    Bellani, Giacomo; Coppadoro, Andrea; Patroniti, Nicolò; Turella, Marta; Arrigoni Marocco, Stefano; Grasselli, Giacomo; Mauri, Tommaso; Pesenti, Antonio

    2014-09-01

    Auto-positive end-expiratory pressure (auto-PEEP) may substantially increase the inspiratory effort during assisted mechanical ventilation. Purpose of this study was to assess whether the electrical activity of the diaphragm (EAdi) signal can be reliably used to estimate auto-PEEP in patients undergoing pressure support ventilation and neurally adjusted ventilatory assist (NAVA) and whether NAVA was beneficial in comparison with pressure support ventilation in patients affected by auto-PEEP. In 10 patients with a clinical suspicion of auto-PEEP, the authors simultaneously recorded EAdi, airway, esophageal pressure, and flow during pressure support and NAVA, whereas external PEEP was increased from 2 to 14 cm H2O. Tracings were analyzed to measure apparent "dynamic" auto-PEEP (decrease in esophageal pressure to generate inspiratory flow), auto-EAdi (EAdi value at the onset of inspiratory flow), and IDEAdi (inspiratory delay between the onset of EAdi and the inspiratory flow). The pressure necessary to overcome auto-PEEP, auto-EAdi, and IDEAdi was significantly lower in NAVA as compared with pressure support ventilation, decreased with increase in external PEEP, although the effect of external PEEP was less pronounced in NAVA. Both auto-EAdi and IDEAdi were tightly correlated with auto-PEEP (r = 0.94 and r = 0.75, respectively). In the presence of auto-PEEP at lower external PEEP levels, NAVA was characterized by a characteristic shape of the airway pressure. In patients with auto-PEEP, NAVA, compared with pressure support ventilation, led to a decrease in the pressure necessary to overcome auto-PEEP, which could be reliably monitored by the electrical activity of the diaphragm before inspiratory flow onset (auto-EAdi).

  11. Classification of Echolocation Calls from 14 Species of Bat by Support Vector Machines and Ensembles of Neural Networks

    Directory of Open Access Journals (Sweden)

    Stuart Parsons

    2009-07-01

    Full Text Available Calls from 14 species of bat were classified to genus and species using discriminant function analysis (DFA, support vector machines (SVM and ensembles of neural networks (ENN. Both SVMs and ENNs outperformed DFA for every species while ENNs (mean identification rate – 97% consistently outperformed SVMs (mean identification rate – 87%. Correct classification rates produced by the ENNs varied from 91% to 100%; calls from six species were correctly identified with 100% accuracy. Calls from the five species of Myotis, a genus whose species are considered difficult to distinguish acoustically, had correct identification rates that varied from 91 – 100%. Five parameters were most important for classifying calls correctly while seven others contributed little to classification performance.

  12. The spatial decision-supporting system combination of RBR & CBR based on artificial neural network and association rules

    Science.gov (United States)

    Tian, Yangge; Bian, Fuling

    2007-06-01

    The technology of artificial intelligence should be imported on the basis of the geographic information system to bring up the spatial decision-supporting system (SDSS). The paper discusses the structure of SDSS, after comparing the characteristics of RBR and CBR, the paper brings up the frame of a spatial decisional system that combines RBR and CBR, which has combined the advantages of them both. And the paper discusses the CBR in agriculture spatial decisions, the application of ANN (Artificial Neural Network) in CBR, and enriching the inference rule base based on association rules, etc. And the paper tests and verifies the design of this system with the examples of the evaluation of the crops' adaptability.

  13. Damage Localization of Cable-Supported Bridges Using Modal Frequency Data and Probabilistic Neural Network

    Directory of Open Access Journals (Sweden)

    X. T. Zhou

    2014-01-01

    Full Text Available This paper presents an investigation on using the probabilistic neural network (PNN for damage localization in the suspension Tsing Ma Bridge (TMB and the cable-stayed Ting Kau Bridge (TKB from simulated noisy modal data. Because the PNN approach describes measurement data in a Bayesian probabilistic framework, it is promising for structural damage detection in noisy conditions. For locating damage on the TMB deck, the main span of the TMB is divided into a number of segments, and damage to the deck members in a segment is classified as one pattern class. The characteristic ensembles (training samples for each pattern class are obtained by computing the modal frequency change ratios from a 3D finite element model (FEM when incurring damage at different members of the same segment and then corrupting the analytical results with random noise. The testing samples for damage localization are obtained in a similar way except that damage is generated at locations different from the training samples. For damage region/type identification of the TKB, a series of pattern classes are defined to depict different scenarios with damage occurring at different portions/components. Research efforts have been focused on evaluating the influence of measurement noise level on the identification accuracy.

  14. LOGIC WITH EXCEPTION ON THE ALGEBRA OF FOURIER-DUAL OPERATIONS: NEURAL NET MECHANISM OF COGNITIVE DISSONANCE REDUCING

    Directory of Open Access Journals (Sweden)

    A. V. Pavlov

    2014-01-01

    Full Text Available A mechanism of cognitive dissonance reducing is demonstrated with approach for non-monotonic fuzzy-valued logics by Fourier-holography technique implementation developing. Cognitive dissonance occurs under perceiving of new information that contradicts to the existing subjective pattern of the outside world, represented by double Fourier-transform cascade with a hologram – neural layers interconnections matrix of inner information representation and logical conclusion. The hologram implements monotonic logic according to “General Modus Ponens” rule. New information is represented by a hologram of exclusion that implements interconnections of logical conclusion and exclusion for neural layers. The latter are linked by Fourier transform that determines duality of the algebra forming operations of conjunction and disjunction. Hologram of exclusion forms conclusion that is dual to the “General Modus Ponens” conclusion. It is shown, that trained for the main rule and exclusion system can be represented by two-layered neural network with separate interconnection matrixes for direct and inverse iterations. The network energy function is involved determining the cyclic dynamics character; dissipative factor causing convergence type of the dynamics is analyzed. Both “General Modus Ponens” and exclusion holograms recording conditions on the dynamics and convergence of the system are demonstrated. The system converges to a stable status, in which logical conclusion doesn’t depend on the inner information. Such kind of dynamics, leading to tolerance forming, is typical for ordinary kind of thinking, aimed at inner pattern of outside world stability. For scientific kind of thinking, aimed at adequacy of the inner pattern of the world, a mechanism is needed to stop the net relaxation; the mechanism has to be external relative to the model of logic. Computer simulation results for the learning conditions adequate to real holograms recording are

  15. Evolutionary and Neural Computing Based Decision Support System for Disease Diagnosis from Clinical Data Sets in Medical Practice.

    Science.gov (United States)

    Sudha, M

    2017-09-27

    As a recent trend, various computational intelligence and machine learning approaches have been used for mining inferences hidden in the large clinical databases to assist the clinician in strategic decision making. In any target data the irrelevant information may be detrimental, causing confusion for the mining algorithm and degrades the prediction outcome. To address this issue, this study attempts to identify an intelligent approach to assist disease diagnostic procedure using an optimal set of attributes instead of all attributes present in the clinical data set. In this proposed Application Specific Intelligent Computing (ASIC) decision support system, a rough set based genetic algorithm is employed in pre-processing phase and a back propagation neural network is applied in training and testing phase. ASIC has two phases, the first phase handles outliers, noisy data, and missing values to obtain a qualitative target data to generate appropriate attribute reduct sets from the input data using rough computing based genetic algorithm centred on a relative fitness function measure. The succeeding phase of this system involves both training and testing of back propagation neural network classifier on the selected reducts. The model performance is evaluated with widely adopted existing classifiers. The proposed ASIC system for clinical decision support has been tested with breast cancer, fertility diagnosis and heart disease data set from the University of California at Irvine (UCI) machine learning repository. The proposed system outperformed the existing approaches attaining the accuracy rate of 95.33%, 97.61%, and 93.04% for breast cancer, fertility issue and heart disease diagnosis.

  16. Investigating neural mechanisms of change of cognitive behavioural therapy for chronic fatigue syndrome: a randomized controlled trial.

    Science.gov (United States)

    van Der Schaaf, Marieke E; Schmits, Iris C; Roerink, Megan; Geurts, Dirk E M; Toni, Ivan; Roelofs, Karin; De Lange, Floris P; Nater, Urs M; van der Meer, Jos W M; Knoop, Hans

    2015-07-03

    Chronic fatigue syndrome (CFS) is characterized by profound and disabling fatigue with no known somatic explanation. Cognitive behavioral therapy (CBT) has proven to be a successful intervention leading to a reduction in fatigue and disability. Based on previous neuroimaging findings, it has been suggested that central neural mechanisms may underlie CFS symptoms and play a role in the change brought on by CBT. In this randomized controlled trial we aim to further investigate the neural mechanisms that underlie fatigue in CFS and their change by CBT. We will conduct a randomized controlled trial in which we collect anatomical and functional magnetic resonance imaging (MRI) measures from female CFS patients before and after CBT (N = 60) or waiting list (N = 30) and compare these with measures from age and education matched healthy controls (N = 30). By including a large treatment group we will also be able to compare patients that benefit from CBT with those that do not. In addition, to further investigate the role of endocrine and immune biomarkers in CFS, we will determine cortisol and cytokine concentrations in blood, hair and/or saliva. This project creates an unique opportunity to enhance our understanding of CFS symptoms and its change by CBT in terms of neuroanatomical, neurofunctional, endocrinological and immunological mechanisms and can help to further improve future treatments strategies. Dutch Trial Register #15852. Registered 9 December 2013 ( http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4311 ).

  17. Effective electric fields along realistic DTI-based neural trajectories for modelling the stimulation mechanisms of TMS.

    Science.gov (United States)

    De Geeter, N; Crevecoeur, G; Leemans, A; Dupré, L

    2015-01-21

    In transcranial magnetic stimulation (TMS), an applied alternating magnetic field induces an electric field in the brain that can interact with the neural system. It is generally assumed that this induced electric field is the crucial effect exciting a certain region of the brain. More specifically, it is the component of this field parallel to the neuron's local orientation, the so-called effective electric field, that can initiate neuronal stimulation. Deeper insights on the stimulation mechanisms can be acquired through extensive TMS modelling. Most models study simple representations of neurons with assumed geometries, whereas we embed realistic neural trajectories computed using tractography based on diffusion tensor images. This way of modelling ensures a more accurate spatial distribution of the effective electric field that is in addition patient and case specific. The case study of this paper focuses on the single pulse stimulation of the left primary motor cortex with a standard figure-of-eight coil. Including realistic neural geometry in the model demonstrates the strong and localized variations of the effective electric field between the tracts themselves and along them due to the interplay of factors such as the tract's position and orientation in relation to the TMS coil, the neural trajectory and its course along the white and grey matter interface. Furthermore, the influence of changes in the coil orientation is studied. Investigating the impact of tissue anisotropy confirms that its contribution is not negligible. Moreover, assuming isotropic tissues lead to errors of the same size as rotating or tilting the coil with 10 degrees. In contrast, the model proves to be less sensitive towards the not well-known tissue conductivity values.

  18. Mechanical support of a ceramic gas turbine vane ring

    Science.gov (United States)

    Shi, Jun; Green, Kevin E.; Mosher, Daniel A.; Holowczak, John E.; Reinhardt, Gregory E.

    2010-07-27

    An assembly for mounting a ceramic turbine vane ring onto a turbine support casing comprises a first metal clamping ring and a second metal clamping ring. The first metal clamping ring is configured to engage with a first side of a tab member of the ceramic turbine vane ring. The second metal clamping ring is configured to engage with a second side of the tab member such that the tab member is disposed between the first and second metal clamping rings.

  19. Antifungal mechanisms supporting boric acid therapy of Candida vaginitis.

    Science.gov (United States)

    De Seta, Francesco; Schmidt, Martin; Vu, Bao; Essmann, Michael; Larsen, Bryan

    2009-02-01

    Boric acid is a commonly cited treatment for recurrent and resistant yeast vaginitis, but data about the extent and mechanism of its antifungal activity are lacking. The aim of this study was to use in vitro methods to understand the spectrum and mechanism of boric acid as a potential treatment for vaginal infection. Yeast and bacterial isolates were tested by agar dilution to determine the intrinsic antimicrobial activity of boric acid. Established microbial physiology methods illuminated the mechanism of the action of boric acid against Candida albicans. C. albicans strains (including fluconazole-resistant strains) were inhibited at concentrations attainable intravaginally; as were bacteria. Broth dilution MICs were between 1563 and 6250 mg/L and boric acid proved fungistatic (also reflected by a decrease in CO(2) generation); prolonged culture at 50,000 mg/L was fungicidal. Several organic acids in yeast nitrogen broth yielded a lower pH than equimolar boric acid and sodium borate but were less inhibitory. Cold or anaerobic incubation protected yeast at high boric acid concentrations. Cells maintained integrity for 6 h in boric acid at 37 degrees C, but after 24 h modest intrusion of propidium iodide occurred; loss of plate count viability preceded uptake of vital stain. Growth at sub-MIC concentrations of boric acid decreased cellular ergosterol. The drug efflux pump CDR1 did not protect Candida as CDR1 expression was abrogated by boric acid. Boric acid interfered with the development of biofilm and hyphal transformation. Boric acid is fungistatic to fungicidal depending on concentration and temperature. Inhibition of oxidative metabolism appears to be a key antifungal mechanism, but inhibition of virulence probably contributes to therapeutic efficacy in vivo.

  20. The emerging role of epigenetic mechanisms in the etiology of neural tube defects

    Science.gov (United States)

    Greene, Nicholas DE; Stanier, Philip

    2011-01-01

    The molecular requirements for neural tube closure are complex. This is illustrated by the occurrence of neural tube defects (NTDs) in many genetic mouse mutants, which implicate a variety of genes, pathways and cellular functions. NTDs are also prevalent birth defects in humans, affecting around 1 per 1,000 pregnancies worldwide. In humans the causation is thought to involve the interplay of fetal genes and the effect of environmental factors. Recent studies on the etiology of human NTDs, as well as analysis of mouse models, have raised the question of the possible involvement of epigenetic factors in determining susceptibility. A consideration of potential causative factors in human NTDs must now include both alterations in the regulation of gene expression, through mutation of promoter or regulatory elements and the additional analysis of epigenetic regulation. Alterations in the epigenetic status can be directly modified by various environmental insults or maternal dietary factors. PMID:21613818

  1. FGF signalling regulates chromatin organisation during neural differentiation via mechanisms that can be uncoupled from transcription.

    Directory of Open Access Journals (Sweden)

    Nishal S Patel

    Full Text Available Changes in higher order chromatin organisation have been linked to transcriptional regulation; however, little is known about how such organisation alters during embryonic development or how it is regulated by extrinsic signals. Here we analyse changes in chromatin organisation as neural differentiation progresses, exploiting the clear spatial separation of the temporal events of differentiation along the elongating body axis of the mouse embryo. Combining fluorescence in situ hybridisation with super-resolution structured illumination microscopy, we show that chromatin around key differentiation gene loci Pax6 and Irx3 undergoes both decompaction and displacement towards the nuclear centre coincident with transcriptional onset. Conversely, down-regulation of Fgf8 as neural differentiation commences correlates with a more peripheral nuclear position of this locus. During normal neural differentiation, fibroblast growth factor (FGF signalling is repressed by retinoic acid, and this vitamin A derivative is further required for transcription of neural genes. We show here that exposure to retinoic acid or inhibition of FGF signalling promotes precocious decompaction and central nuclear positioning of differentiation gene loci. Using the Raldh2 mutant as a model for retinoid deficiency, we further find that such changes in higher order chromatin organisation are dependent on retinoid signalling. In this retinoid deficient condition, FGF signalling persists ectopically in the elongating body, and importantly, we find that inhibiting FGF receptor (FGFR signalling in Raldh2-/- embryos does not rescue differentiation gene transcription, but does elicit both chromatin decompaction and nuclear position change. These findings demonstrate that regulation of higher order chromatin organisation during differentiation in the embryo can be uncoupled from the machinery that promotes transcription and, for the first time, identify FGF as an extrinsic signal that

  2. Effect of Heterogeneity on Decorrelation Mechanisms in Spiking Neural Networks: A Neuromorphic-Hardware Study

    Directory of Open Access Journals (Sweden)

    Thomas Pfeil

    2016-05-01

    Full Text Available High-level brain function, such as memory, classification, or reasoning, can be realized by means of recurrent networks of simplified model neurons. Analog neuromorphic hardware constitutes a fast and energy-efficient substrate for the implementation of such neural computing architectures in technical applications and neuroscientific research. The functional performance of neural networks is often critically dependent on the level of correlations in the neural activity. In finite networks, correlations are typically inevitable due to shared presynaptic input. Recent theoretical studies have shown that inhibitory feedback, abundant in biological neural networks, can actively suppress these shared-input correlations and thereby enable neurons to fire nearly independently. For networks of spiking neurons, the decorrelating effect of inhibitory feedback has so far been explicitly demonstrated only for homogeneous networks of neurons with linear subthreshold dynamics. Theory, however, suggests that the effect is a general phenomenon, present in any system with sufficient inhibitory feedback, irrespective of the details of the network structure or the neuronal and synaptic properties. Here, we investigate the effect of network heterogeneity on correlations in sparse, random networks of inhibitory neurons with nonlinear, conductance-based synapses. Emulations of these networks on the analog neuromorphic-hardware system Spikey allow us to test the efficiency of decorrelation by inhibitory feedback in the presence of hardware-specific heterogeneities. The configurability of the hardware substrate enables us to modulate the extent of heterogeneity in a systematic manner. We selectively study the effects of shared input and recurrent connections on correlations in membrane potentials and spike trains. Our results confirm that shared-input correlations are actively suppressed by inhibitory feedback also in highly heterogeneous networks exhibiting broad

  3. Music training relates to the development of neural mechanisms of selective auditory attention

    OpenAIRE

    Dana L. Strait; Jessica Slater; Samantha O’Connell; Nina Kraus

    2015-01-01

    Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated with executive control: in adult musicians, attention decreases variability in auditory-evoked response...

  4. Mechanical performance of implant-supported posterior crowns.

    Science.gov (United States)

    de Kok, Paul; Kleverlaan, Cornelis J; de Jager, Niek; Kuijs, Ruud; Feilzer, Albert J

    2015-07-01

    The fracture of implant-supported restorations, especially of the veneering layer, is a common problem in dentistry. Monolithic ceramic or resin restorations might help solve this problem. The purpose of this in vitro study was to obtain additional insight into the risk of fracture of implant-supported restorations. Identical crowns (n=10) of 10 different ceramic and composite resin materials were cemented on conventional abutments on implant replicas embedded in polymethyl methacrylate blocks. The specimens were subjected to compressive load in a universal testing machine to record initial load to failure (ILF). Additionally, the flexural strength (FS), compressive strength (CS), and elastic modulus (E) of the investigated materials were determined. These results were used in a finite element analysis model of a composite resin and a lithium disilicate crown. Anatomic contour zirconia (Lava Plus) crowns had the highest ILF (6065 N), followed by lithium disilicate (IPS e.max) (2788 N) and the composite resin materials (Protemp 4, Majesty Flow, Telio CAD, Estenia C&B, Lava Ultimate, VITA Enamic) (2386 to 1935 N). Veneered zirconia (Lava) crowns showed the lowest ILF (1477 N). The highest FS, CS, and E were found for Lava Plus and IPS e.max. No direct relationship was found between ILF and the FS, CS, or E. The finite element analysis showed stresses that did not exceed the FS or CS of IPS e.max. The surface roughness of these crowns might have caused initial failure at relatively low stresses. In this laboratory study, monolithic implant-supported crowns showed a higher ILF than conventional veneered ceramic crowns. Monolithic ceramic restorations might perform better than composite resin crowns. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  5. Automatic Defect Detection of Fasteners on the Catenary Support Device Using Deep Convolutional Neural Network

    NARCIS (Netherlands)

    Chen, Junwen; Liu, Zhigang; Wang, H.; Nunez Vicencio, Alfredo; Han, Zhiwei

    2017-01-01

    The excitation and vibration triggered by the long-term operation of railway vehicles inevitably result in defective states of catenary support devices. With the massive construction of high-speed electrified railways, automatic defect detection of diverse and plentiful fasteners on the catenary

  6. Pre-operative prediction of advanced prostatic cancer using clinical decision support systems: accuracy comparison between support vector machine and artificial neural network.

    Science.gov (United States)

    Kim, Sang Youn; Moon, Sung Kyoung; Jung, Dae Chul; Hwang, Sung Il; Sung, Chang Kyu; Cho, Jeong Yeon; Kim, Seung Hyup; Lee, Jiwon; Lee, Hak Jong

    2011-01-01

    The purpose of the current study was to develop support vector machine (SVM) and artificial neural network (ANN) models for the pre-operative prediction of advanced prostate cancer by using the parameters acquired from transrectal ultrasound (TRUS)-guided prostate biopsies, and to compare the accuracies between the two models. Five hundred thirty-two consecutive patients who underwent prostate biopsies and prostatectomies for prostate cancer were divided into the training and test groups (n = 300 versus n = 232). From the data in the training group, two clinical decision support systems (CDSSs-[SVM and ANN]) were constructed with input (age, prostate specific antigen level, digital rectal examination, and five biopsy parameters) and output data (the probability for advanced prostate cancer [> pT3a]). From the data of the test group, the accuracy of output data was evaluated. The areas under the receiver operating characteristic (ROC) curve (AUC) were calculated to summarize the overall performances, and a comparison of the ROC curves was performed (p cancer. The performance of SVM is superior to ANN in the pre-operative prediction of advanced prostate cancer.

  7. Neural mechanisms of rhythm-based temporal prediction: Delta phase-locking reflects temporal predictability but not rhythmic entrainment.

    Directory of Open Access Journals (Sweden)

    Assaf Breska

    2017-02-01

    Full Text Available Predicting the timing of upcoming events enables efficient resource allocation and action preparation. Rhythmic streams, such as music, speech, and biological motion, constitute a pervasive source for temporal predictions. Widely accepted entrainment theories postulate that rhythm-based predictions are mediated by synchronizing low-frequency neural oscillations to the rhythm, as indicated by increased phase concentration (PC of low-frequency neural activity for rhythmic compared to random streams. However, we show here that PC enhancement in scalp recordings is not specific to rhythms but is observed to the same extent in less periodic streams if they enable memory-based prediction. This is inconsistent with the predictions of a computational entrainment model of stronger PC for rhythmic streams. Anticipatory change in alpha activity and facilitation of electroencephalogram (EEG manifestations of response selection are also comparable between rhythm- and memory-based predictions. However, rhythmic sequences uniquely result in obligatory depression of preparation-related premotor brain activity when an on-beat event is omitted, even when it is strategically beneficial to maintain preparation, leading to larger behavioral costs for violation of prediction. Thus, while our findings undermine the validity of PC as a sign of rhythmic entrainment, they constitute the first electrophysiological dissociation, to our knowledge, between mechanisms of rhythmic predictions and of memory-based predictions: the former obligatorily lead to resonance-like preparation patterns (that are in line with entrainment, while the latter allow flexible resource allocation in time regardless of periodicity in the input. Taken together, they delineate the neural mechanisms of three distinct modes of preparation: continuous vigilance, interval-timing-based prediction and rhythm-based prediction.

  8. Language Learning Enhanced by Massive Multiple Online Role-Playing Games (MMORPGs) and the Underlying Behavioral and Neural Mechanisms

    Science.gov (United States)

    Zhang, Yongjun; Song, Hongwen; Liu, Xiaoming; Tang, Dinghong; Chen, Yue-e; Zhang, Xiaochu

    2017-01-01

    Massive Multiple Online Role-Playing Games (MMORPGs) have increased in popularity among children, juveniles, and adults since MMORPGs’ appearance in this digital age. MMORPGs can be applied to enhancing language learning, which is drawing researchers’ attention from different fields and many studies have validated MMORPGs’ positive effect on language learning. However, there are few studies on the underlying behavioral or neural mechanism of such effect. This paper reviews the educational application of the MMORPGs based on relevant macroscopic and microscopic studies, showing that gamers’ overall language proficiency or some specific language skills can be enhanced by real-time online interaction with peers and game narratives or instructions embedded in the MMORPGs. Mechanisms underlying the educational assistant role of MMORPGs in second language learning are discussed from both behavioral and neural perspectives. We suggest that attentional bias makes gamers/learners allocate more cognitive resources toward task-related stimuli in a controlled or an automatic way. Moreover, with a moderating role played by activation of reward circuit, playing the MMORPGs may strengthen or increase functional connectivity from seed regions such as left anterior insular/frontal operculum (AI/FO) and visual word form area to other language-related brain areas. PMID:28303097

  9. Language Learning Enhanced by Massive Multiple Online Role-Playing Games (MMORPGs) and the Underlying Behavioral and Neural Mechanisms.

    Science.gov (United States)

    Zhang, Yongjun; Song, Hongwen; Liu, Xiaoming; Tang, Dinghong; Chen, Yue-E; Zhang, Xiaochu

    2017-01-01

    Massive Multiple Online Role-Playing Games (MMORPGs) have increased in popularity among children, juveniles, and adults since MMORPGs' appearance in this digital age. MMORPGs can be applied to enhancing language learning, which is drawing researchers' attention from different fields and many studies have validated MMORPGs' positive effect on language learning. However, there are few studies on the underlying behavioral or neural mechanism of such effect. This paper reviews the educational application of the MMORPGs based on relevant macroscopic and microscopic studies, showing that gamers' overall language proficiency or some specific language skills can be enhanced by real-time online interaction with peers and game narratives or instructions embedded in the MMORPGs. Mechanisms underlying the educational assistant role of MMORPGs in second language learning are discussed from both behavioral and neural perspectives. We suggest that attentional bias makes gamers/learners allocate more cognitive resources toward task-related stimuli in a controlled or an automatic way. Moreover, with a moderating role played by activation of reward circuit, playing the MMORPGs may strengthen or increase functional connectivity from seed regions such as left anterior insular/frontal operculum (AI/FO) and visual word form area to other language-related brain areas.

  10. Untangling the neurobiology of coping styles in rodents: Towards neural mechanisms underlying individual differences in disease susceptibility.

    Science.gov (United States)

    de Boer, Sietse F; Buwalda, Bauke; Koolhaas, Jaap M

    2017-03-01

    Considerable individual differences exist in trait-like patterns of behavioral and physiological responses to salient environmental challenges. This individual variation in stress coping styles has an important functional role in terms of health and fitness. Hence, understanding the neural embedding of coping style variation is fundamental for biobehavioral neurosciences in probing individual disease susceptibility. This review outlines individual differences in trait-aggressiveness as an adaptive component of the natural sociobiology of rats and mice, and highlights that these reflect the general style of coping that varies from proactive (aggressive) to reactive (docile). We propose that this qualitative coping style can be disentangled into multiple quantitative behavioral domains, e.g., flexibility/impulse control, emotional reactivity and harm avoidance/reward processing, that each are encoded into selective neural circuitries. Since functioning of all these brain circuitries rely on fine-tuned serotonin signaling, autoinhibitory control mechanisms of serotonergic neuron (re)activity are crucial in orchestrating general coping style. Untangling the precise neuromolecular mechanisms of different coping styles will provide a roadmap for developing better therapeutic strategies of stress-related diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. 47 CFR 54.709 - Computations of required contributions to universal service support mechanisms.

    Science.gov (United States)

    2010-10-01

    ... demand for the federal universal service support mechanisms for high-cost areas, low-income consumers... universal service support mechanisms. 54.709 Section 54.709 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Administration § 54.709...

  12. Human neural progenitor cells decrease photoreceptor degeneration, normalize opsin distribution and support synapse structure in cultured porcine retina.

    Science.gov (United States)

    Mollick, Tanzina; Mohlin, Camilla; Johansson, Kjell

    2016-09-01

    Retinal neurodegenerative disorders like retinitis pigmentosa, age-related macular degeneration, diabetic retinopathy and retinal detachment decrease retinal functionality leading to visual impairment. The pathological events are characterized by photoreceptor degeneration, synaptic disassembly, remodeling of postsynaptic neurons and activation of glial cells. Despite intense research, no effective treatment has been found for these disorders. The current study explores the potential of human neural progenitor cell (hNPC) derived factors to slow the degenerative processes in adult porcine retinal explants. Retinas were cultured for 3 days with or without hNPCs as a feeder layer and investigated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), immunohistochemical, western blot and quantitative real time-polymerase chain reaction (qRT-PCR) techniques. TUNEL showed that hNPCs had the capacity to limit photoreceptor cell death. Among cone photoreceptors, hNPC coculture resulted in better maintenance of cone outer segments and reduced opsin mislocalization. Additionally, maintained synaptic structural integrity and preservation of second order calbindin positive horizontal cells was also observed. However, Müller cell gliosis only seemed to be alleviated in terms of reduced Müller cell density. Our observations indicate that at 3 days of coculture, hNPC derived factors had the capacity to protect photoreceptors, maintain synaptic integrity and support horizontal cell survival. Human neural progenitor cell applied treatment modalities may be an effective strategy to help maintain retinal functionality in neurodegenerative pathologies. Whether hNPCs can independently hinder Müller cell gliosis by utilizing higher concentrations or by combination with other pharmacological agents still needs to be determined. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Neural mechanisms of feature conjunction learning: enduring changes in occipital cortex after a week of training.

    Science.gov (United States)

    Frank, Sebastian M; Reavis, Eric A; Tse, Peter U; Greenlee, Mark W

    2014-04-01

    Most visual activities, whether reading, driving, or playing video games, require rapid detection and identification of learned patterns defined by arbitrary conjunctions of visual features. Initially, such detection is slow and inefficient, but it can become fast and efficient with training. To determine how the brain learns to process conjunctions of visual features efficiently, we trained participants over eight consecutive days to search for a target defined by an arbitrary conjunction of color and location among distractors with a different conjunction of the same features. During each training session, we measured brain activity with functional magnetic resonance imaging (fMRI). The speed of visual search for feature conjunctions improved dramatically within just a few days. These behavioral improvements were correlated with increased neural responses to the stimuli in visual cortex. This suggests that changes in neural processing in visual cortex contribute to the speeding up of visual feature conjunction search. We find evidence that this effect is driven by an increase in the signal-to-noise ratio (SNR) of the BOLD signal for search targets over distractors. In a control condition where target and distractor identities were exchanged after training, learned search efficiency was abolished, suggesting that the primary improvement was perceptual learning for the search stimuli, not task-learning. Moreover, when participants were retested on the original task after nine months without further training, the acquired changes in behavior and brain activity were still present, showing that this can be an enduring form of learning and neural reorganization. Copyright © 2013 Wiley Periodicals, Inc.

  14. Review of International Experience with Renewable Energy Obligation Support Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, R.

    2005-06-01

    The main policy instruments currently used in the EU Member States to achieve the targets set for electricity produced from renewable energy sources are: (1) the quota obligation system; (2) the feed-in tariff system; and (3) the tendering system. The current study aims to review the experience gained with the quota obligation system. The report provides an overview of the regions where obligation systems have been implemented and contains a detailed evaluation of the performance of the obligation systems in the USA, the UK and in Sweden. The obligation systems in these countries have been evaluated based on the following criteria: Effectiveness; Market efficiency; Certainty for the renewable energy industry; Cost effectiveness; Stakeholder support for the obligation system; and Equity. The evaluation of international experiences with the obligation system gives rise to a mixed picture. Although an obligation in theory is effective and cost effective, it seems too early to conclude that the system delivers these promises in practice. On the one hand this is due to the limited period of implementation that makes it hard to distinguish between the direct effect of the system and some teething problems that will be solved in due time. On the other hand, the conclusion can be drawn that the obligation is a complex system, which will only function well if designed carefully. It does seem worthwhile, however, to continue monitoring the experiences with the obligation system abroad, because this will further reveal whether the system is indeed effective and cost effective in practice. In the longer term, e.g. beyond 2010, the introduction of an obligation system in the Netherlands could be considered. Finally, as the design of support schemes is being improved, it appears that the basic concepts of both the obligation system and the feed in system have been refined in such a way that the two systems are gradually converging. An important difference between the two systems

  15. [Neural Mechanism of Major Depressive Disorder and Bipolar Disorder in Voxel-Based Morphometric Studies].

    Science.gov (United States)

    Matsuo, Koji

    2017-05-01

    Major depressive disorder and bipolar disorder both possess the characteristic of abnormal mood regulation. Evidence of voxel-based morphometric (VBM) studies has been accumulated, and patients with both disorders show small gray matter volumes in the anterior cingulate, dorsolateral prefrontal cortex, insula, and regions related to emotion regulation. These small gray matter volumes were also shown to be associated with the family history and severity of the disease. Overall, the neural network relevant to mood regulation is thought to be involved in the pathophysiology of both major depressive disorder and bipolar disorder.

  16. Neural Mechanisms Underlying Musical Pitch Perception and Clinical Applications Including Developmental Dyslexia.

    Science.gov (United States)

    Yuskaitis, Christopher J; Parviz, Mahsa; Loui, Psyche; Wan, Catherine Y; Pearl, Phillip L

    2015-08-01

    Music production and perception invoke a complex set of cognitive functions that rely on the integration of sensorimotor, cognitive, and emotional pathways. Pitch is a fundamental perceptual attribute of sound and a building block for both music and speech. Although the cerebral processing of pitch is not completely understood, recent advances in imaging and electrophysiology have provided insight into the functional and anatomical pathways of pitch processing. This review examines the current understanding of pitch processing and behavioral and neural variations that give rise to difficulties in pitch processing, and potential applications of music education for language processing disorders such as dyslexia.

  17. Neural Mechanisms Underlying Musical Pitch Perception and Clinical Applications including Developmental Dyselxia

    Science.gov (United States)

    Yuskaitis, Christopher J.; Parviz, Mahsa; Loui, Psyche; Wan, Catherine Y.; Pearl, Phillip L.

    2017-01-01

    Music production and perception invoke a complex set of cognitive functions that rely on the integration of sensory-motor, cognitive, and emotional pathways. Pitch is a fundamental perceptual attribute of sound and a building block for both music and speech. Although the cerebral processing of pitch is not completely understood, recent advances in imaging and electrophysiology have provided insight into the functional and anatomical pathways of pitch processing. This review examines the current understanding of pitch processing, behavioral and neural variations that give rise to difficulties in pitch processing, and potential applications of music education for language processing disorders such as dyslexia. PMID:26092314

  18. Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training

    Directory of Open Access Journals (Sweden)

    Nosratollah Hedayatpour

    2015-01-01

    Full Text Available Eccentric exercise is characterized by initial unfavorable effects such as subcellular muscle damage, pain, reduced fiber excitability, and initial muscle weakness. However, stretch combined with overload, as in eccentric contractions, is an effective stimulus for inducing physiological and neural adaptations to training. Eccentric exercise-induced adaptations include muscle hypertrophy, increased cortical activity, and changes in motor unit behavior, all of which contribute to improved muscle function. In this brief review, neuromuscular adaptations to different forms of exercise are reviewed, the positive training effects of eccentric exercise are presented, and the implications for training are considered.

  19. Detection of heat abduction on the walls by artificial neural network and selection of materials with decision support system

    Directory of Open Access Journals (Sweden)

    Egemen Tekkanat

    2017-08-01

    Full Text Available Today energy conservation is a very important issue in the world and Turkey. The aim of this study is to minimize the heat abduction, thus to save energy by utilizing the factors to prevent the heat abduction on the walls of buildings. First of all, a back-propagation network model with artificial neural network model was used for the factors that can cause heat loss on the walls. Whether the walls have insulation were considered. After that, Decision Support Systems were used for heat insulation to select the appropriate materials. A Decision Support Model with Analytic Hierarchy Process (AHP was recommended to meet the needs of a customer best and to make better decisions for the selection of the materials. The method was used by construction firms for their decision processes for the best materials and the results were evaluated. After the evaluations were done, the factors that cause heat loss were considered and it became clear which factors were more important for the prevention of heat loss.

  20. Exploiting elasticity: Modeling the influence of neural control on mechanics and energetics of ankle muscle-tendons during human hopping.

    Science.gov (United States)

    Robertson, Benjamin D; Sawicki, Gregory S

    2014-07-21

    We present a simplified Hill-type model of the human triceps surae-Achilles tendon complex working on a gravitational-inertial load during cyclic contractions (i.e. vertical hopping). Our goal was to determine the role that neural control plays in governing muscle, or contractile element (CE), and tendon, or series elastic element (SEE), mechanics and energetics within a compliant muscle-tendon unit (MTU). We constructed a 2D parameter space consisting of many combinations of stimulation frequency and magnitude (i.e. neural control strategies). We compared the performance of each control strategy by evaluating peak force and average positive mechanical power output for the system (MTU) and its respective components (CE, SEE), force-length (F-L) and -velocity (F-V) operating point of the CE during active force production, average metabolic rate for the CE, and both MTU and CE apparent efficiency. Our results suggest that frequency of stimulation plays a primary role in governing whole-MTU mechanics. These include the phasing of both activation and peak force relative to minimum MTU length, average positive power, and apparent efficiency. Stimulation amplitude was primarily responsible for governing average metabolic rate and within MTU mechanics, including peak force generation and elastic energy storage and return in the SEE. Frequency and amplitude of stimulation both played integral roles in determining CE F-L operating point, with both higher frequency and amplitude generally corresponding to lower CE strains, reduced injury risk, and elimination of the need for passive force generation in the CE parallel elastic element (PEE). Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Using ecology to guide the study of cognitive and neural mechanisms of different aspects of spatial memory in food-hoarding animals.

    Science.gov (United States)

    Smulders, Tom V; Gould, Kristy L; Leaver, Lisa A

    2010-03-27

    Understanding the survival value of behaviour does not tell us how the mechanisms that control this behaviour work. Nevertheless, understanding survival value can guide the study of these mechanisms. In this paper, we apply this principle to understanding the cognitive mechanisms that support cache retrieval in scatter-hoarding animals. We believe it is too simplistic to predict that all scatter-hoarding animals will outperform non-hoarding animals on all tests of spatial memory. Instead, we argue that we should look at the detailed ecology and natural history of each species. This understanding of natural history then allows us to make predictions about which aspects of spatial memory should be better in which species. We use the natural hoarding behaviour of the three best-studied groups of scatter-hoarding animals to make predictions about three aspects of their spatial memory: duration, capacity and spatial resolution, and we test these predictions against the existing literature. Having laid out how ecology and natural history can be used to predict detailed cognitive abilities, we then suggest using this approach to guide the study of the neural basis of these abilities. We believe that this complementary approach will reveal aspects of memory processing that would otherwise be difficult to discover.

  2. Neural correlates of informational cascades: brain mechanisms of social influence on belief updating.

    Science.gov (United States)

    Huber, Rafael E; Klucharev, Vasily; Rieskamp, Jörg

    2015-04-01

    Informational cascades can occur when rationally acting individuals decide independently of their private information and follow the decisions of preceding decision-makers. In the process of updating beliefs, differences in the weighting of private and publicly available social information may modulate the probability that a cascade starts in a decisive way. By using functional magnetic resonance imaging, we examined neural activity while participants updated their beliefs based on the decisions of two fictitious stock market traders and their own private information, which led to a final decision of buying one of two stocks. Computational modeling of the behavioral data showed that a majority of participants overweighted private information. Overweighting was negatively correlated with the probability of starting an informational cascade in trials especially prone to conformity. Belief updating by private information was related to activity in the inferior frontal gyrus/anterior insula, the dorsolateral prefrontal cortex and the parietal cortex; the more a participant overweighted private information, the higher the activity in the inferior frontal gyrus/anterior insula and the lower in the parietal-temporal cortex. This study explores the neural correlates of overweighting of private information, which underlies the tendency to start an informational cascade. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  3. Moving towards causality in attention-deficit hyperactivity disorder: overview of neural and genetic mechanisms

    Science.gov (United States)

    Gallo, Eduardo F; Posner, Jonathan

    2016-01-01

    Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by developmentally inappropriate levels of inattention and hyperactivity or impulsivity. The heterogeneity of its clinical manifestations and the differential responses to treatment and varied prognoses have long suggested myriad underlying causes. Over the past decade, clinical and basic research efforts have uncovered many behavioural and neurobiological alterations associated with ADHD, from genes to higher order neural networks. Here, we review the neurobiology of ADHD by focusing on neural circuits implicated in the disorder and discuss how abnormalities in circuitry relate to symptom presentation and treatment. We summarise the literature on genetic variants that are potentially related to the development of ADHD, and how these, in turn, might affect circuit function and relevant behaviours. Whether these underlying neurobiological factors are causally related to symptom presentation remains unresolved. Therefore, we assess efforts aimed at disentangling issues of causality, and showcase the shifting research landscape towards endophenotype refinement in clinical and preclinical settings. Furthermore, we review approaches being developed to understand the neurobiological underpinnings of this complex disorder including the use of animal models, neuromodulation, and pharmaco-imaging studies. PMID:27183902

  4. Neural mechanisms underlying contextual dependency of subjective values: converging evidence from monkeys and humans.

    Science.gov (United States)

    Abitbol, Raphaëlle; Lebreton, Maël; Hollard, Guillaume; Richmond, Barry J; Bouret, Sébastien; Pessiglione, Mathias

    2015-02-04

    A major challenge for decision theory is to account for the instability of expressed preferences across time and context. Such variability could arise from specific properties of the brain system used to assign subjective values. Growing evidence has identified the ventromedial prefrontal cortex (VMPFC) as a key node of the human brain valuation system. Here, we first replicate this observation with an fMRI study in humans showing that subjective values of painting pictures, as expressed in explicit pleasantness ratings, are specifically encoded in the VMPFC. We then establish a bridge with monkey electrophysiology, by comparing single-unit activity evoked by visual cues between the VMPFC and the orbitofrontal cortex. At the neural population level, expected reward magnitude was only encoded in the VMPFC, which also reflected subjective cue values, as expressed in Pavlovian appetitive responses. In addition, we demonstrate in both species that the additive effect of prestimulus activity on evoked activity has a significant impact on subjective values. In monkeys, the factor dominating prestimulus VMPFC activity was trial number, which likely indexed variations in internal dispositions related to fatigue or satiety. In humans, prestimulus VMPFC activity was externally manipulated through changes in the musical context, which induced a systematic bias in subjective values. Thus, the apparent stochasticity of preferences might relate to the VMPFC automatically aggregating the values of contextual features, which would bias subsequent valuation because of temporal autocorrelation in neural activity. Copyright © 2015 the authors 0270-6474/15/352308-13$15.00/0.

  5. Neural mechanisms of brain plasticity with complex cognitive training in healthy seniors.

    Science.gov (United States)

    Chapman, Sandra B; Aslan, Sina; Spence, Jeffrey S; Hart, John J; Bartz, Elizabeth K; Didehbani, Nyaz; Keebler, Molly W; Gardner, Claire M; Strain, Jeremy F; DeFina, Laura F; Lu, Hanzhang

    2015-02-01

    Complex mental activity induces improvements in cognition, brain function, and structure in animals and young adults. It is not clear to what extent the aging brain is capable of such plasticity. This study expands previous evidence of generalized cognitive gains after mental training in healthy seniors. Using 3 MRI-based measurements, that is, arterial spin labeling MRI, functional connectivity, and diffusion tensor imaging, we examined brain changes across 3 time points pre, mid, and post training (12 weeks) in a randomized sample (n = 37) who received cognitive training versus a control group. We found significant training-related brain state changes at rest; specifically, 1) increases in global and regional cerebral blood flow (CBF), particularly in the default mode network and the central executive network, 2) greater connectivity in these same networks, and 3) increased white matter integrity in the left uncinate demonstrated by an increase in fractional anisotropy. Improvements in cognition were identified along with significant CBF correlates of the cognitive gains. We propose that cognitive training enhances resting-state neural activity and connectivity, increasing the blood supply to these regions via neurovascular coupling. These convergent results provide preliminary evidence that neural plasticity can be harnessed to mitigate brain losses with cognitive training in seniors. © The Author 2013. Published by Oxford University Press.

  6. Learning to Associate Auditory and Visual Stimuli: Behavioral and Neural Mechanisms

    Science.gov (United States)

    Altieri, Nicholas; Stevenson, Ryan; Wallace, Mark T.; Wenger, Michael J.

    2014-01-01

    The ability to effectively combine sensory inputs across modalities is vital for acquiring a unified percept of events. For example, watching a hammer hit a nail while simultaneously identifying the sound as originating from the event requires the ability to identify spatio-temporal congruencies and statistical regularities. In this study, we applied a reaction time (RT) and hazard function measure known as capacity (e.g., Townsend and Ashby, 1978) to quantify the extent to which observers learn paired associations between simple auditory and visual patterns in a model theoretic manner. As expected, results showed that learning was associated with an increase in accuracy, but more significantly, an increase in capacity. The aim of this study was to associate capacity measures of multisensory learning, with neural based measures, namely mean Global Field Power (GFP). We observed a co-variation between an increase in capacity, and a decrease in GFP amplitude as learning occurred. This suggests that capacity constitutes a reliable behavioral index of efficient energy expenditure in the neural domain. PMID:24276220

  7. FINGERPRINT CLASSIFICATION BASED ON RECURSIVE NEURAL NETWORK WITH SUPPORT VECTOR MACHINE

    Directory of Open Access Journals (Sweden)

    T. Chakravarthy

    2011-01-01

    Full Text Available Fingerprint classification based on statistical and structural (RNN and SVM approach. RNNs are trained on a structured representation of the fingerprint image. They are also used to extract a set of distributed features of the fingerprint which can be integrated in this support vector machine. SVMs are combined with a new error correcting codes scheme. This approach has two main advantages. (a It can tolerate the presence of ambiguous fingerprint images in the training set and (b It can effectively identify the most difficult fingerprint images in the test set. In this experiment on the fingerprint database NIST-4 (National Institute of Science and Technology, our best classification accuracy of 94.7% is obtained by training SVM on both fingerCode and RNN –extracted futures of segmentation algorithm which has used very sophisticated “region growing process”.

  8. Support Vector Machine and Artificial Neural Network Models for the Classification of Grapevine Varieties Using a Portable NIR Spectrophotometer

    Science.gov (United States)

    Gutiérrez, Salvador; Tardaguila, Javier; Fernández-Novales, Juan; Diago, María P.

    2015-01-01

    The identification of different grapevine varieties, currently attended using visual ampelometry, DNA analysis and very recently, by hyperspectral analysis under laboratory conditions, is an issue of great importance in the wine industry. This work presents support vector machine and artificial neural network’s modelling for grapevine varietal classification from in-field leaf spectroscopy. Modelling was attempted at two scales: site-specific and a global scale. Spectral measurements were obtained on the near-infrared (NIR) spectral range between 1600 to 2400 nm under field conditions in a non-destructive way using a portable spectrophotometer. For the site specific approach, spectra were collected from the adaxial side of 400 individual leaves of 20 grapevine (Vitis vinifera L.) varieties one week after veraison. For the global model, two additional sets of spectra were collected one week before harvest from two different vineyards in another vintage, each one consisting on 48 measurement from individual leaves of six varieties. Several combinations of spectra scatter correction and smoothing filtering were studied. For the training of the models, support vector machines and artificial neural networks were employed using the pre-processed spectra as input and the varieties as the classes of the models. The results from the pre-processing study showed that there was no influence whether using scatter correction or not. Also, a second-degree derivative with a window size of 5 Savitzky-Golay filtering yielded the highest outcomes. For the site-specific model, with 20 classes, the best results from the classifiers thrown an overall score of 87.25% of correctly classified samples. These results were compared under the same conditions with a model trained using partial least squares discriminant analysis, which showed a worse performance in every case. For the global model, a 6-class dataset involving samples from three different vineyards, two years and leaves

  9. Support Vector Machine and Artificial Neural Network Models for the Classification of Grapevine Varieties Using a Portable NIR Spectrophotometer.

    Science.gov (United States)

    Gutiérrez, Salvador; Tardaguila, Javier; Fernández-Novales, Juan; Diago, María P

    2015-01-01

    The identification of different grapevine varieties, currently attended using visual ampelometry, DNA analysis and very recently, by hyperspectral analysis under laboratory conditions, is an issue of great importance in the wine industry. This work presents support vector machine and artificial neural network's modelling for grapevine varietal classification from in-field leaf spectroscopy. Modelling was attempted at two scales: site-specific and a global scale. Spectral measurements were obtained on the near-infrared (NIR) spectral range between 1600 to 2400 nm under field conditions in a non-destructive way using a portable spectrophotometer. For the site specific approach, spectra were collected from the adaxial side of 400 individual leaves of 20 grapevine (Vitis vinifera L.) varieties one week after veraison. For the global model, two additional sets of spectra were collected one week before harvest from two different vineyards in another vintage, each one consisting on 48 measurement from individual leaves of six varieties. Several combinations of spectra scatter correction and smoothing filtering were studied. For the training of the models, support vector machines and artificial neural networks were employed using the pre-processed spectra as input and the varieties as the classes of the models. The results from the pre-processing study showed that there was no influence whether using scatter correction or not. Also, a second-degree derivative with a window size of 5 Savitzky-Golay filtering yielded the highest outcomes. For the site-specific model, with 20 classes, the best results from the classifiers thrown an overall score of 87.25% of correctly classified samples. These results were compared under the same conditions with a model trained using partial least squares discriminant analysis, which showed a worse performance in every case. For the global model, a 6-class dataset involving samples from three different vineyards, two years and leaves

  10. Source of human ventilatory chaos: lessons from switching controlled mechanical ventilation to inspiratory pressure support in critically ill patients.

    Science.gov (United States)

    Mangin, Laurence; Fiamma, Marie-Noëlle; Straus, Christian; Derenne, Jean-Philippe; Zelter, Marc; Clerici, Christine; Similowski, Thomas

    2008-04-30

    Ventilatory flow measured at the airway opening in humans exhibits a complex dynamics that has the features of chaos. Currently available data point to a neural origin of this feature, but the role of respiratory mechanics has not been specifically assessed. In this aim, we studied 17 critically ill mechanically ventilated patients during a switch form an entirely machine-controlled assistance mode (assist-controlled ventilation ACV) to a patient-driven mode (inspiratory pressure support IPS). Breath-by-breath respiratory variability was assessed with the coefficient of variation of tidal volume, total cycle time, inspiratory time, expiratory time, mean inspiratory flow, duty cycle. The detection of chaos was performed with the noise titration technique. When present, chaos was characterized with numerical indexes (correlation dimension, irregularity; largest Lyapunov exponent, sensitivity to initial conditions). Expectedly, the coefficients of variations of the respiratory variables were higher during IPS than during ACV. During ACV, noise titration failed to detect nonlinearities in 12 patients who did not exhibit signs of spontaneous respiratory activity. This indicates that the mechanical properties of the respiratory system were not sufficient to produce ventilatory chaos in the presence of a nonlinear command (ventilator clock). A positive noise limit was found in the remaining 5 cases, but these patients exhibited signs of active expiratory control (highly variable expiratory time, respiratory frequency higher than the set frequency). A positive noise limit was also observed in 16/17 patients during IPS (pmechanics, if any.

  11. Learning from feedback: the neural mechanisms of feedback processing facilitating better performance.

    Science.gov (United States)

    Luft, Caroline Di Bernardi

    2014-03-15

    Different levels of feedback, from sensory signals to verbal advice, are needed not only for learning new skills, but also for monitoring performance. A great deal of research has focused on the electrophysiological correlates of feedback processing and how they relate to good learning. In this paper, studies on the EEG correlates of learning from feedback are reviewed. The main objective is to discuss these findings whilst also considering some key theoretical aspects of learning. The learning processes, its operational definition and the feedback characteristics are discussed and used as reference for integrating the findings in the literature. The EEG correlates of feedback processing for learning using various analytical approaches are discussed, including ERPs, oscillations and inter-site synchronization. How these EEG responses to feedback are related to learning is discussed, highlighting the gaps in the literature and suggesting future directions for understanding the neural underpinnings of learning from feedback. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Neural Mechanisms Underlying Affective Theory of Mind in Violent Antisocial Personality Disorder and/or Schizophrenia.

    Science.gov (United States)

    Schiffer, Boris; Pawliczek, Christina; Müller, Bernhard W; Wiltfang, Jens; Brüne, Martin; Forsting, Michael; Gizewski, Elke R; Leygraf, Norbert; Hodgins, Sheilagh

    2017-10-21

    Among violent offenders with schizophrenia, there are 2 sub-groups, one with and one without, conduct disorder (CD) and antisocial personality disorder (ASPD), who differ as to treatment response and alterations of brain structure. The present study aimed to determine whether the 2 groups also differ in Theory of Mind and neural activations subsuming this task. Five groups of men were compared: 3 groups of violent offenders-schizophrenia plus CD/ASPD, schizophrenia with no history of antisocial behavior prior to illness onset, and CD/ASPD with no severe mental illness-and 2 groups of non-offenders, one with schizophrenia and one without (H). Participants completed diagnostic interviews, the Psychopathy Checklist Screening Version Interview, the Interpersonal Reactivity Index, authorized access to clinical and criminal files, and underwent functional magnetic resonance imaging while completing an adapted version of the Reading-the-Mind-in-the-Eyes Task (RMET). Relative to H, nonviolent and violent men with schizophrenia and not CD/ASPD performed more poorly on the RMET, while violent offenders with CD/ASPD, both those with and without schizophrenia, performed similarly. The 2 groups of violent offenders with CD/ASPD, both those with and without schizophrenia, relative to the other groups, displayed higher levels of activation in a network of prefrontal and temporal-parietal regions and reduced activation in the amygdala. Relative to men without CD/ASPD, both groups of violent offenders with CD/ASPD displayed a distinct pattern of neural responses during emotional/mental state attribution pointing to distinct and comparatively successful processing of social information. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. The neural network as a part of decision support system for quality management for production objects in machining process

    Directory of Open Access Journals (Sweden)

    Cherepanska I.Yu.

    2017-04-01

    Full Text Available The research discusses the use of artificial neural networks (ANN as components of a decision support system (DSS to automate quality control manufacturing facilities machining business at the production, which should be focused on the analysis of large amounts of heterogeneous information. The necessity to use ANN as a part of DSS is justified by the fact that quality control during production is multistage and time-consuming process that is formalized difficult, and moreover requires considerable information and material costs for the efficiency of manufacturing operations performed. Taking into account the existing experience of successful use of ANN to solve difficult formal problems associated with handling large volumes of diverse and rapidly changing information, the authors synthesized ANN for automated determination of the causes deterioration of the quality of production objects (PO in the performance of manufacturing operations application. Particular attention is paid to the definition of the dimension of the hidden layer ANN synthesized due to the fact that today still there is no analytical expression to determine the dimension of the hidden layer ANN and size of the latter is determined only by the experimental results of ANN several different structures by comparison the results, in particular the value of mean square error.

  14. Non-metallic coating thickness prediction using artificial neural network and support vector machine with time resolved thermography

    Science.gov (United States)

    Wang, Hongjin; Hsieh, Sheng-Jen; Peng, Bo; Zhou, Xunfei

    2016-07-01

    A method without requirements on knowledge about thermal properties of coatings or those of substrates will be interested in the industrial application. Supervised machine learning regressions may provide possible solution to the problem. This paper compares the performances of two regression models (artificial neural networks (ANN) and support vector machines for regression (SVM)) with respect to coating thickness estimations made based on surface temperature increments collected via time resolved thermography. We describe SVM roles in coating thickness prediction. Non-dimensional analyses are conducted to illustrate the effects of coating thicknesses and various factors on surface temperature increments. It's theoretically possible to correlate coating thickness with surface increment. Based on the analyses, the laser power is selected in such a way: during the heating, the temperature increment is high enough to determine the coating thickness variance but low enough to avoid surface melting. Sixty-one pain-coated samples with coating thicknesses varying from 63.5 μm to 571 μm are used to train models. Hyper-parameters of the models are optimized by 10-folder cross validation. Another 28 sets of data are then collected to test the performance of the three methods. The study shows that SVM can provide reliable predictions of unknown data, due to its deterministic characteristics, and it works well when used for a small input data group. The SVM model generates more accurate coating thickness estimates than the ANN model.

  15. Neural systems supporting cognitive-affective interactions in adolescence: The role of puberty and implications for affective disorders

    Directory of Open Access Journals (Sweden)

    Cecile D. Ladouceur

    2012-08-01

    Full Text Available Evidence from longitudinal studies suggests that adolescence may represent a period of vulnerability that, in the context of adverse events, could contribute to developmental trajectories toward behavioral and emotional health problems, including affective disorders. Adolescence is also a sensitive period for the development of neural systems supporting cognitive-affective processes, which have been implicated in the pathophysiology of affective disorders such as anxiety and mood disorders. In particular, the onset of puberty brings about a cascade of physical, hormonal, psychological, and social changes that contribute in complex ways to the development of these systems. This article provides a brief overview of neuroimaging research pertaining to the development of cognitive-affective processes in adolescence. It also includes a brief review of evidence from animal and human neuroimaging studies suggesting that sex steroids influence the connectivity between prefrontal cortical and subcortical limbic regions in ways that contribute to increased reactivity to emotionally salient stimuli. We integrate these findings in the context of a developmental affective neuroscience framework suggesting that the impact of rising levels of sex steroids during puberty on fronto-limbic connectivity may be even greater in the context of protracted development of prefrontal cortical regions in adolescence. We conclude by discussing the implications of these findings for future research aimed at identifying neurodevelopmental markers of risk for future onset of affective disorders.

  16. A cross-sectional evaluation of meditation experience on electroencephalography data by artificial neural network and support vector machine classifiers.

    Science.gov (United States)

    Lee, Yu-Hao; Hsieh, Ya-Ju; Shiah, Yung-Jong; Lin, Yu-Huei; Chen, Chiao-Yun; Tyan, Yu-Chang; GengQiu, JiaCheng; Hsu, Chung-Yao; Chen, Sharon Chia-Ju

    2017-04-01

    To quantitate the meditation experience is a subjective and complex issue because it is confounded by many factors such as emotional state, method of meditation, and personal physical condition. In this study, we propose a strategy with a cross-sectional analysis to evaluate the meditation experience with 2 artificial intelligence techniques: artificial neural network and support vector machine. Within this analysis system, 3 features of the electroencephalography alpha spectrum and variant normalizing scaling are manipulated as the evaluating variables for the detection of accuracy. Thereafter, by modulating the sliding window (the period of the analyzed data) and shifting interval of the window (the time interval to shift the analyzed data), the effect of immediate analysis for the 2 methods is compared. This analysis system is performed on 3 meditation groups, categorizing their meditation experiences in 10-year intervals from novice to junior and to senior. After an exhausted calculation and cross-validation across all variables, the high accuracy rate >98% is achievable under the criterion of 0.5-minute sliding window and 2 seconds shifting interval for both methods. In a word, the minimum analyzable data length is 0.5 minute and the minimum recognizable temporal resolution is 2 seconds in the decision of meditative classification. Our proposed classifier of the meditation experience promotes a rapid evaluation system to distinguish meditation experience and a beneficial utilization of artificial techniques for the big-data analysis.

  17. Analysis of Power Laws, Shape Collapses, and Neural Complexity: New Techniques and MATLAB Support via the NCC Toolbox.

    Science.gov (United States)

    Marshall, Najja; Timme, Nicholas M; Bennett, Nicholas; Ripp, Monica; Lautzenhiser, Edward; Beggs, John M

    2016-01-01

    Neural systems include interactions that occur across many scales. Two divergent methods for characterizing such interactions have drawn on the physical analysis of critical phenomena and the mathematical study of information. Inferring criticality in neural systems has traditionally rested on fitting power laws to the property distributions of "neural avalanches" (contiguous bursts of activity), but the fractal nature of avalanche shapes has recently emerged as another signature of criticality. On the other hand, neural complexity, an information theoretic measure, has been used to capture the interplay between the functional localization of brain regions and their integration for higher cognitive functions. Unfortunately, treatments of all three methods-power-law fitting, avalanche shape collapse, and neural complexity-have suffered from shortcomings. Empirical data often contain biases that introduce deviations from true power law in the tail and head of the distribution, but deviations in the tail have often been unconsidered; avalanche shape collapse has required manual parameter tuning; and the estimation of neural complexity has relied on small data sets or statistical assumptions for the sake of computational efficiency. In this paper we present technical advancements in the analysis of criticality and complexity in neural systems. We use maximum-likelihood estimation to automatically fit power laws with left and right cutoffs, present the first automated shape collapse algorithm, and describe new techniques to account for large numbers of neural variables and small data sets in the calculation of neural complexity. In order to facilitate future research in criticality and complexity, we have made the software utilized in this analysis freely available online in the MATLAB NCC (Neural Complexity and Criticality) Toolbox.

  18. Modeling and optimization of anode-supported solid oxide fuel cells on cell parameters via artificial neural network and genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Bozorgmehri, S. [School of Mechanical Engineering, College of Engineering, University of Tehran, North Kargar at Jalal-Exp Way, Tehran (Iran, Islamic Republic of); Renewable Energy Department, Niroo Research Institute (NRI), End of Dadman Blvd., Shahrak Ghodes, Tehran (Iran, Islamic Republic of); Hamedi, M. [School of Mechanical Engineering, College of Engineering, University of Tehran, North Kargar at Jalal-Exp Way, Tehran (Iran, Islamic Republic of)

    2012-02-15

    An artificial neural network (ANN) and a genetic algorithm (GA) are employed to model and optimize cell parameters to improve the performance of singular, intermediate-temperature, solid oxide fuel cells (IT-SOFCs). The ANN model uses a feed-forward neural network with an error back-propagation algorithm. The ANN is trained using experimental data as a black-box without using physical models. The developed model is able to predict the performance of the SOFC. An optimization algorithm is utilized to select the optimal SOFC parameters. The optimal values of four cell parameters (anode support thickness, anode support porosity, electrolyte thickness, and functional layer cathode thickness) are determined by using the GA under different conditions. The results show that these optimum cell parameters deliver the highest maximum power density under different constraints on the anode support thickness, porosity, and electrolyte thickness. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Exploring the developmental mechanisms underlying Wolf-Hirschhorn Syndrome: Evidence for defects in neural crest cell migration.

    Science.gov (United States)

    Rutherford, Erin L; Lowery, Laura Anne

    2016-12-01

    Wolf-Hirschhorn Syndrome (WHS) is a neurodevelopmental disorder characterized by mental retardation, craniofacial malformation, and defects in skeletal and heart development. The syndrome is associated with irregularities on the short arm of chromosome 4, including deletions of varying sizes and microduplications. Many of these genotypic aberrations in humans have been correlated with the classic WHS phenotype, and animal models have provided a context for mapping these genetic irregularities to specific phenotypes; however, there remains a significant knowledge gap concerning the cell biological mechanisms underlying these phenotypes. This review summarizes literature that has made recent contributions to this topic, drawing from the vast body of knowledge detailing the genetic particularities of the disorder and the more limited pool of information on its cell biology. Finally, we propose a novel characterization for WHS as a pathophysiology owing in part to defects in neural crest cell motility and migration during development. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Optimization of a polymer composite employing molecular mechanic simulations and artificial neural networks for a novel intravaginal bioadhesive drug delivery device.

    Science.gov (United States)

    Ndesendo, Valence M K; Pillay, Viness; Choonara, Yahya E; du Toit, Lisa C; Kumar, Pradeep; Buchmann, Eckhart; Meyer, Leith C R; Khan, Riaz A

    2012-01-01

    This study aimed at elucidating an optimal synergistic polymer composite for achieving a desirable molecular bioadhesivity and Matrix Erosion of a bioactive-loaded Intravaginal Bioadhesive Polymeric Device (IBPD) employing Molecular Mechanic Simulations and Artificial Neural Networks (ANN). Fifteen lead caplet-shaped devices were formulated by direct compression with the model bioactives zidovudine and polystyrene sulfonate. The Matrix Erosion was analyzed in simulated vaginal fluid to assess the critical integrity. Blueprinting the molecular mechanics of bioadhesion between vaginal epithelial glycoprotein (EGP), mucin (MUC) and the IBPD were performed on HyperChem 8.0.8 software (MM+ and AMBER force fields) for the quantification and characterization of correlative molecular interactions during molecular bioadhesion. Results proved that the IBPD bioadhesivity was pivoted on the conformation, orientation, and poly(acrylic acid) (PAA) composition that interacted with EGP and MUC present on the vaginal epithelium due to heterogeneous surface residue distributions (free energy= -46.33 kcalmol(-1)). ANN sensitivity testing as a connectionist model enabled strategic polymer selection for developing an IBPD with an optimally prolonged Matrix Erosion and superior molecular bioadhesivity (ME = 1.21-7.68%; BHN = 2.687-4.981 N/mm(2)). Molecular modeling aptly supported the EGP-MUC-PAA molecular interaction at the vaginal epithelium confirming the role of PAA in bioadhesion of the IBPD once inserted into the posterior fornix of the vagina.

  1. Application of Artificial Neural Network and Support Vector Machines in Predicting Metabolizable Energy in Compound Feeds for Pigs.

    Science.gov (United States)

    Ahmadi, Hamed; Rodehutscord, Markus

    2017-01-01

    In the nutrition literature, there are several reports on the use of artificial neural network (ANN) and multiple linear regression (MLR) approaches for predicting feed composition and nutritive value, while the use of support vector machines (SVM) method as a new alternative approach to MLR and ANN models is still not fully investigated. The MLR, ANN, and SVM models were developed to predict metabolizable energy (ME) content of compound feeds for pigs based on the German energy evaluation system from analyzed contents of crude protein (CP), ether extract (EE), crude fiber (CF), and starch. A total of 290 datasets from standardized digestibility studies with compound feeds was provided from several institutions and published papers, and ME was calculated thereon. Accuracy and precision of developed models were evaluated, given their produced prediction values. The results revealed that the developed ANN [R2 = 0.95; root mean square error (RMSE) = 0.19 MJ/kg of dry matter] and SVM (R2 = 0.95; RMSE = 0.21 MJ/kg of dry matter) models produced better prediction values in estimating ME in compound feed than those produced by conventional MLR (R2 = 0.89; RMSE = 0.27 MJ/kg of dry matter). The developed ANN and SVM models produced better prediction values in estimating ME in compound feed than those produced by conventional MLR; however, there were not obvious differences between performance of ANN and SVM models. Thus, SVM model may also be considered as a promising tool for modeling the relationship between chemical composition and ME of compound feeds for pigs. To provide the readers and nutritionist with the easy and rapid tool, an Excel® calculator, namely, SVM_ME_pig, was created to predict the metabolizable energy values in compound feeds for pigs using developed support vector machine model.

  2. Neurofeedback of slow cortical potentials: neural mechanisms and feasibility of a placebo-controlled design in healthy adults

    Directory of Open Access Journals (Sweden)

    Holger eGevensleben

    2014-12-01

    Full Text Available To elucidate basic mechanisms underlying neurofeedback we investigated neural mechanisms of training of slow cortical potentials by considering EEG- and fMRI. Additionally, we analyzed the feasibility of a double-blind, placebo-controlled design in NF research based on regulation performance during treatment sessions and self-assessment of the participants. Twenty healthy adults participated in 16 sessions of SCP training: 9 participants received regular SCP training, 11 participants received sham feedback. At three time points (pre, intermediate, post fMRI and EEG/ERP-measurements were conducted during a continuous performance test (CPT. Performance-data during the sessions (regulation performance in the treatment group and the placebo group were analyzed. Analysis of EEG-activity revealed in the SCP group a strong enhancement of the CNV (electrode Cz at the intermediate assessment, followed by a decrease back to baseline at the post-treatment assessment. In contrast, in the placebo group a continuous but smaller increase of the CNV could be obtained from pre to post assessment. The increase of the CNV in the SCP group at intermediate testing was superior to the enhancement in the placebo group. The changes of the CNV were accompanied by a continuous improvement in the test performance of the CPT from pre to intermediate to post assessment comparable in both groups. The change of the CNV in the SCP group is interpreted as an indicator of neural plasticity and efficiency while an increase of the CNV in the placebo group might reflect learning and improved timing due to the frequent task repetition.In the fMRI analysis evidence was obtained for neuronal plasticity. After regular SCP neurofeedback activation in the posterior parietal cortex decreased from the pre- to the intermediate measurement and increased again in the post measurement, inversely following the U-shaped increase and decrease of the tCNV EEG amplitude in the SCP-trained group

  3. Activational and effort-related aspects of motivation: neural mechanisms and implications for psychopathology.

    Science.gov (United States)

    Salamone, John D; Yohn, Samantha E; López-Cruz, Laura; San Miguel, Noemí; Correa, Mercè

    2016-05-01

    Motivation has been defined as the process that allows organisms to regulate their internal and external environment, and control the probability, proximity and availability of stimuli. As such, motivation is a complex process that is critical for survival, which involves multiple behavioural functions mediated by a number of interacting neural circuits. Classical theories of motivation suggest that there are both directional and activational aspects of motivation, and activational aspects (i.e. speed and vigour of both the instigation and persistence of behaviour) are critical for enabling organisms to overcome work-related obstacles or constraints that separate them from significant stimuli. The present review discusses the role of brain dopamine and related circuits in behavioural activation, exertion of effort in instrumental behaviour, and effort-related decision-making, based upon both animal and human studies. Impairments in behavioural activation and effort-related aspects of motivation are associated with psychiatric symptoms such as anergia, fatigue, lassitude and psychomotor retardation, which cross multiple pathologies, including depression, schizophrenia, and Parkinson's disease. Therefore, this review also attempts to provide an interdisciplinary approach that integrates findings from basic behavioural neuroscience, behavioural economics, clinical neuropsychology, psychiatry, and neurology, to provide a coherent framework for future research and theory in this critical field. Although dopamine systems are a critical part of the brain circuitry regulating behavioural activation, exertion of effort, and effort-related decision-making, mesolimbic dopamine is only one part of a distributed circuitry that includes multiple neurotransmitters and brain areas. Overall, there is a striking similarity between the brain areas involved in behavioural activation and effort-related processes in rodents and in humans. Animal models of effort-related decision

  4. Determination of the mechanical and physical properties of cartilage by coupling poroelastic-based finite element models of indentation with artificial neural networks.

    Science.gov (United States)

    Arbabi, Vahid; Pouran, Behdad; Campoli, Gianni; Weinans, Harrie; Zadpoor, Amir A

    2016-03-21

    One of the most widely used techniques to determine the mechanical properties of cartilage is based on indentation tests and interpretation of the obtained force-time or displacement-time data. In the current computational approaches, one needs to simulate the indentation test with finite element models and use an optimization algorithm to estimate the mechanical properties of cartilage. The modeling procedure is cumbersome, and the simulations need to be repeated for every new experiment. For the first time, we propose a method for fast and accurate estimation of the mechanical and physical properties of cartilage as a poroelastic material with the aid of artificial neural networks. In our study, we used finite element models to simulate the indentation for poroelastic materials with wide combinations of mechanical and physical properties. The obtained force-time curves are then divided into three parts: the first two parts of the data is used for training and validation of an artificial neural network, while the third part is used for testing the trained network. The trained neural network receives the force-time curves as the input and provides the properties of cartilage as the output. We observed that the trained network could accurately predict the properties of cartilage within the range of properties for which it was trained. The mechanical and physical properties of cartilage could therefore be estimated very fast, since no additional finite element modeling is required once the neural network is trained. The robustness of the trained artificial neural network in determining the properties of cartilage based on noisy force-time data was assessed by introducing noise to the simulated force-time data. We found that the training procedure could be optimized so as to maximize the robustness of the neural network against noisy force-time data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Optimization Design of the Ultra-High-Speed Vertical Rotor’s Supporting Mechanism

    Directory of Open Access Journals (Sweden)

    Yongguang Liu

    2014-01-01

    Full Text Available How to increase the rotational speed and decrease vibration of the rotor in the acceleration has become an attractive subject, especially for the vertical rotors. This paper introduces a novel supporting mechanism to make the vertical rotor work at 80000 r/min smoothly. How to design and optimize the sensitive parameters of the supporting mechanism is the core problem to reduce the vibration in passing through critical speeds. Therefore, the FEM (finite element method considering the gyroscopic couple is introduced to get the dynamic characteristic of the rotor system. The matching principle of the upper and lower supporting mechanism in the two-degree freedom system is extended to the multiple degree-freedom system, which is applied to optimize the parameters of the supporting mechanism combining with dynamic characteristic of the rotors system. At last, the rotor system can work at 80000 r/min smoothly in experiment.

  6. Standardized practice design with electronic support mechanisms for surgical process improvement: reducing mechanical ventilation time.

    Science.gov (United States)

    Cook, David J; Pulido, Juan N; Thompson, Jeffrey E; Dearani, Joseph A; Ritter, Matthew J; Hanson, Andrew C; Borah, Bijan J; Habermann, Elizabeth B

    2014-12-01

    Hospital surgical care is complex and subject to unwarranted variation. As part of a multiyear effort, we sought to reduce variability in intraoperative care and management of mechanical ventilation in cardiac surgery. We identified a patient population whose care could be standardized and implemented a protocol-based practice model reinforced by electronic mechanisms. In a large cardiac surgery practice, we built a standardized practice model between 2009 and 2011. We compared mechanical ventilation time before (2008) and after (2012) implementation. To ensure groups were comparable, propensity analysis matched patients from the 2 operative years. In 2012, more than 50% of all cardiac surgical patients were managed with our standardized care model; of those, 769 were one-to-one matched with patients undergoing surgery in 2008. Patients had a mix of coronary artery bypass grafting, valve surgery, and combined procedures. Our practice model reduced median mechanical ventilation duration from 9.3 to 6.3 hours (2008 and 2012) (P Variability in ventilation time was also reduced. We demonstrate that in more than 50% of all cardiac surgical patients, a standardized practice model can be used to achieve better results. Clinical outcomes are improved and unwarranted variability is reduced. Success is driven by clear patient identification and well-defined protocols that are clearly communicated both by electronic tools and by empowerment of bedside providers to advance care when clinical criteria are met.

  7. Neural mechanisms underlying changes in stress-sensitivity across the menstrual cycle.

    Science.gov (United States)

    Ossewaarde, Lindsey; Hermans, Erno J; van Wingen, Guido A; Kooijman, Sabine C; Johansson, Inga-Maj; Bäckström, Torbjörn; Fernández, Guillén

    2010-01-01

    Hormonal fluctuations across the menstrual cycle are thought to play a central role in premenstrual mood symptoms. In agreement, fluctuations in gonadal hormone levels affect brain processes in regions involved in emotion regulation. Recent findings, however, implicate psychological stress as a potential mediating factor and thus, we investigated whether effects of moderate psychological stress on relevant brain regions interact with menstrual cycle phase. Twenty-eight healthy women were tested in a crossover design with menstrual cycle phase (late luteal versus late follicular) and stress (stress induction versus control) as within-subject factors. After stress induction (or control), we probed neural responses to facial expressions using fMRI. During the late luteal phase, negative affect was highest and the stress-induced increase in heart rate was mildly augmented. fMRI data of the control condition replicate previous findings of elevated amygdala and medial prefrontal cortex responses when comparing the late luteal with the late follicular phase. Importantly, stress induction had opposite effects in the two cycle phases, with unexpected lower response magnitudes in the late luteal phase. Moreover, the larger the increase in allopregnanolone concentration across the menstrual cycle was, the smaller the amygdala and medial prefrontal cortex responses were after stress induction in the late luteal phase. Our findings show that moderate psychological stress influences menstrual cycle effects on activity in the emotion regulation circuitry. These results provide potential insights into how fluctuations in allopregnanolone that naturally occur during the menstrual cycle may change stress vulnerability.

  8. Changes in neural mechanisms of cognitive control during the transition from late adolescence to young adulthood.

    Science.gov (United States)

    Veroude, Kim; Jolles, Jelle; Croiset, Gerda; Krabbendam, Lydia

    2013-07-01

    The transition from late adolescence to young adulthood is marked by anatomical maturation of various brain regions. In parallel, defining life changes take place, such as entrance into college. Up till now research has not focused on functional brain differences during this particular developmental stage. The current cross-sectional fMRI study investigates age differences in cognitive control by comparing late adolescents, 18-19 years old, with young adults, 23-25 years old. Seventy-four male and female medical students carried out a combined cognitive and emotional Stroop task. Overall, lateral frontoparietal and medial parietal activation was observed during cognitive interference resolution. Young adults showed stronger activation in the dorsomedial prefrontal cortex, left inferior frontal gyrus, left middle temporal gyrus and middle cingulate, compared to late adolescents. During emotional interference resolution, the left precentral and postcentral gyrus were involved across age and sex. The dorsomedial prefrontal cortex and precuneus were activated more in young adults than in late adolescents. No sex-related differences were found in this homogeneous sample. The results suggest that the neural bases of cognitive control continue to change between late adolescence and young adulthood. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Neural Mechanisms of Reading Facial Emotions in Young and Older Adults

    Science.gov (United States)

    Ebner, Natalie C.; Johnson, Marcia K.; Fischer, Håkan

    2012-01-01

    The ability to read and appropriately respond to emotions in others is central for successful social interaction. Young and older adults are better at identifying positive than negative facial expressions and also expressions of young than older faces. Little, however, is known about the neural processes associated with reading different emotions, particularly in faces of different ages, in samples of young and older adults. During fMRI, young and older participants identified expressions in happy, neutral, and angry young and older faces. The results suggest a functional dissociation of ventromedial prefrontal cortex (vmPFC) and dorsomedial prefrontal cortex (dmPFC) in reading facial emotions that is largely comparable in young and older adults: Both age groups showed greater vmPFC activity to happy compared to angry or neutral faces, which was positively correlated with expression identification for happy compared to angry faces. In contrast, both age groups showed greater activity in dmPFC to neutral or angry than happy faces which was negatively correlated with expression identification for neutral compared to happy faces. A similar region of dmPFC showed greater activity for older than young faces, but no brain-behavior correlations. Greater vmPFC activity in the present study may reflect greater affective processing involved in reading happy compared to neutral or angry faces. Greater dmPFC activity may reflect more cognitive control involved in decoding and/or regulating negative emotions associated with neutral or angry than happy, and older than young, faces. PMID:22798953

  10. Mechanisms of neural reorganization in chronic stroke subjects after virtual reality training.

    Science.gov (United States)

    Saleh, S; Bagce, H; Qiu, Q; Fluet, G; Merians, A; Adamovich, S; Tunik, E

    2011-01-01

    This study investigates patterns of brain reorganization in chronic stroke subjects after two weeks of robot-assisted arm and hand training in virtual reality (VR). Four subjects were studied with event-related fMRI while doing simple paretic hand finger movements before (double baseline) and after training. Bilateral hand movements were recorded and used to provide real-time feedback to subjects during scanning to eliminate performance confounds on fMRI results. The kinematic parameters of each movement were also used in the general linear model with the BOLD signal to investigate training-induced changes in neuromotor coupling. Univariate analysis showed an increase in BOLD signal in the ipsilesional hemisphere in two subjects and a decrease in activity in the other two subjects. Seed voxel based functional connectivity analysis revealed an increase in connectivity between ipsilesional motor cortex and bilateral sensorimotor cortex during finger movements in all four subjects. Hemispheric laterality index values showed a tendency to decrease reflecting a reduction in the over-dominance of the contralesional hemisphere. The study is novel in terms of 1) tracking finger movement during a motor task in the scanner, 2) monitoring motor performance during the experiment and 3) giving online visual feedback of subjects' movement. This pilot study introduces a novel approach to study neural plasticity by combining measures of regional intensity, interregional interactions (using functional connectivity analysis and hemispheric laterality index), and modulation in the strength of neuromotor coupling.

  11. Do the right thing: neural network mechanisms of memory formation, expression and update in Drosophila.

    Science.gov (United States)

    Cognigni, Paola; Felsenberg, Johannes; Waddell, Scott

    2017-12-16

    When animals learn, plasticity in brain networks that respond to specific cues results in a change in the behavior that these cues elicit. Individual network components in the mushroom bodies of the fruit fly Drosophila melanogaster represent cues, learning signals and behavioral outcomes of learned experience. Recent findings have highlighted the importance of dopamine-driven plasticity and activity in feedback and feedforward connections, between various elements of the mushroom body neural network. These computational motifs have been shown to be crucial for long term olfactory memory consolidation, integration of internal states, re-evaluation and updating of learned information. The often recurrent circuit anatomy and a prolonged requirement for activity in parts of these underlying networks, suggest that self-sustained and precisely timed activity is a fundamental feature of network computations in the insect brain. Together these processes allow flies to continuously adjust the content of their learned knowledge and direct their behavior in a way that best represents learned expectations and serves their most pressing current needs. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Stability of Neural Firing in the Trigeminal Nuclei under Mechanical Whisker Stimulation

    Directory of Open Access Journals (Sweden)

    Valeri A. Makarov

    2010-01-01

    Full Text Available Sensory information handling is an essentially nonstationary process even under a periodic stimulation. We show how the time evolution of ridges in the wavelet spectrum of spike trains can be used for quantification of the dynamical stability of the neuronal responses to a stimulus. We employ this method to study neuronal responses in trigeminal nuclei of the rat provoked by tactile whisker stimulation. Neurons from principalis (Pr5 and interpolaris (Sp5i show the maximal stability at the intermediate (50 ms stimulus duration, whereas Sp5o cells “prefer” shorter (10 ms stimulation. We also show that neurons in all three nuclei can perform as stimulus frequency filters. The response stability of about 33% of cells exhibits low-pass frequency dynamics. About 57% of cells have band-pass dynamics with the optimal frequency at 5 Hz for Pr5 and Sp5i, and 4 Hz for Sp5o, and the remaining 10% show no prominent dependence on the stimulus frequency. This suggests that the neural coding scheme in trigeminal nuclei is not fixed, but instead it adapts to the stimulus characteristics.

  13. Music training relates to the development of neural mechanisms of selective auditory attention

    Directory of Open Access Journals (Sweden)

    Dana L. Strait

    2015-04-01

    Full Text Available Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated with executive control: in adult musicians, attention decreases variability in auditory-evoked responses recorded over prefrontal cortex to a greater extent than in nonmusicians. We aimed to determine whether this musician-associated effect emerges during childhood, when selective attention and inhibitory control are under development. We compared cortical auditory-evoked variability to attended and ignored speech streams in musicians and nonmusicians across three age groups: preschoolers, school-aged children and young adults. Results reveal that childhood music training is associated with reduced auditory-evoked response variability recorded over prefrontal cortex during selective auditory attention in school-aged child and adult musicians. Preschoolers, on the other hand, demonstrate no impact of selective attention on cortical response variability and no musician distinctions. This finding is consistent with the gradual emergence of attention during this period and may suggest no pre-existing differences in this attention-related cortical metric between children who undergo music training and those who do not.

  14. Music training relates to the development of neural mechanisms of selective auditory attention.

    Science.gov (United States)

    Strait, Dana L; Slater, Jessica; O'Connell, Samantha; Kraus, Nina

    2015-04-01

    Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated with executive control: in adult musicians, attention decreases variability in auditory-evoked responses recorded over prefrontal cortex to a greater extent than in nonmusicians. We aimed to determine whether this musician-associated effect emerges during childhood, when selective attention and inhibitory control are under development. We compared cortical auditory-evoked variability to attended and ignored speech streams in musicians and nonmusicians across three age groups: preschoolers, school-aged children and young adults. Results reveal that childhood music training is associated with reduced auditory-evoked response variability recorded over prefrontal cortex during selective auditory attention in school-aged child and adult musicians. Preschoolers, on the other hand, demonstrate no impact of selective attention on cortical response variability and no musician distinctions. This finding is consistent with the gradual emergence of attention during this period and may suggest no pre-existing differences in this attention-related cortical metric between children who undergo music training and those who do not. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Sex differences in the neural mechanisms mediating addiction: a new synthesis and hypothesis

    Directory of Open Access Journals (Sweden)

    Becker Jill B

    2012-06-01

    Full Text Available Abstract In this review we propose that there are sex differences in how men and women enter onto the path that can lead to addiction. Males are more likely than females to engage in risky behaviors that include experimenting with drugs of abuse, and in susceptible individuals, they are drawn into the spiral that can eventually lead to addiction. Women and girls are more likely to begin taking drugs as self-medication to reduce stress or alleviate depression. For this reason women enter into the downward spiral further along the path to addiction, and so transition to addiction more rapidly. We propose that this sex difference is due, at least in part, to sex differences in the organization of the neural systems responsible for motivation and addiction. Additionally, we suggest that sex differences in these systems and their functioning are accentuated with addiction. In the current review we discuss historical, cultural, social and biological bases for sex differences in addiction with an emphasis on sex differences in the neurotransmitter systems that are implicated.

  16. Mechanisms linking social ties and support to physical and mental health.

    Science.gov (United States)

    Thoits, Peggy A

    2011-06-01

    Over the past 30 years investigators have called repeatedly for research on the mechanisms through which social relationships and social support improve physical and psychological well-being, both directly and as stress buffers. I describe seven possible mechanisms: social influence/social comparison, social control, role-based purpose and meaning (mattering), self-esteem, sense of control, belonging and companionship, and perceived support availability. Stress-buffering processes also involve these mechanisms. I argue that there are two broad types of support, emotional sustenance and active coping assistance, and two broad categories of supporters, significant others and experientially similar others, who specialize in supplying different types of support to distressed individuals. Emotionally sustaining behaviors and instrumental aid from significant others and empathy, active coping assistance, and role modeling from similar others should be most efficacious in alleviating the physical and emotional impacts of stressors.

  17. Different mechanisms must be considered to explain the increase in hippocampal neural precursor cell proliferation by physical activity

    Directory of Open Access Journals (Sweden)

    Rupert W Overall

    2016-08-01

    Full Text Available The number of proliferating neural precursor cells in the adult hippocampus is strongly increased by physical activity. The mechanisms through which this behavioral stimulus induces cell proliferation, however, are not yet understood. In fact, even the mode of proliferation of the stem and progenitor cells is not exactly known. Evidence exists for several mechanisms including cell cycle shortening, reduced cell death and stem cell recruitment, but as yet no model can account for all observations. An appreciation of how the cells proliferate, however, is crucial to our ability to model the neurogenic process and predict its behavior in response to pro-neurogenic stimuli. In a recent study, we addressed modulation of the cell cycle length as one possible mode of regulation of precursor cell proliferation in running mice. Our results indicated that the observed increase in number of proliferating cells could not be explained through a shortening of the cell cycle. We must therefore consider other mechanisms by which physical activity leads to enhanced precursor cell proliferation. Here we review the evidence for and against several different hypotheses and discuss the implications for future research in the field.

  18. Recurrent or prolonged mechanical circulatory support: bridge to recovery or road to nowhere?

    Science.gov (United States)

    d'Udekem, Yves; Shime, Nobuaki; Lou, Song; MacLaren, Graeme

    2013-06-01

    Remarkable outcomes have been reported after prolonged mechanical circulatory support in the pediatric population, but there is yet no clear delineation of the duration beyond which supporting a child becomes futile. The likelihood of survival in patients supported on extracorporeal membrane oxygenation for respiratory failure decreases with the length of support. However, extracorporeal membrane oxygenation can be successfully used in these patients for long periods (weeks to months) provided adequate support is maintained without complications. This is not the case with cardiac failure and mechanical circulatory support.Extracorporeal membrane oxygenation is usually the initial form of mechanical circulatory support used in patients with primary refractory myocardial dysfunction. There is evidence and consensus that if the patient shows no signs of recovery after a maximum duration of 2 weeks, he or she should be transitioned to a ventricular assist device, which allows prolonged support. In post-cardiac surgery patients, survival is only anecdotal beyond 12 days of extracorporeal membrane oxygenation support, and myocardial recovery is exceptionally rare after this time period unless new diagnoses and management strategies are formulated.Repeat extracorporeal membrane oxygenation should generally not be offered to patients unless it is established that support was withdrawn prematurely or a new intervention is planned. Repeat extracorporeal membrane oxygenation may achieve some improvement in early survival, but the long-term outcomes of survivors are so poor that these attempts cannot be generally recommended unless organ transplantation is an option.

  19. Efficiency Assessment of Support Mechanisms for Wood-Fired Cogeneration Development in Estonia

    Science.gov (United States)

    Volkova, Anna; Siirde, Andres

    2010-01-01

    There are various support mechanisms for wood-fired cogeneration plants, which include both support for cogeneration development and stimulation for increasing consumption of renewable energy sources. The efficiency of these mechanisms is analysed in the paper. Overview of cogeneration development in Estonia is given with the focus on wood-fired cogeneration. Legislation acts and amendments, related to cogeneration support schemes, were described. For evaluating the efficiency of support mechanisms an indicator - fuel cost factor was defined. This indicator includes the costs related to the chosen fuel influence on the final electricity generation costs without any support mechanisms. The wood fuel cost factors were compared with the fuel cost factors for peat and oil shale. For calculating the fuel cost factors, various data sources were used. The fuel prices data were based on the average cost of fuels in Estonia for the period from 2000 till 2008. The data about operating and maintenance costs, related to the fuel type in the case of comparing wood fuel and oil shale fuel were taken from the CHP Balti and Eesti reports. The data about operating and maintenance costs used for peat and wood fuel comparison were taken from the Tallinn Elektrijaam reports. As a result, the diagrams were built for comparing wood and its competitive fuels. The decision boundary lines were constructed on the diagram for the situation, when no support was provided for wood fuels and for the situations, when various support mechanisms were provided during the last 12 years.

  20. In silico log P prediction for a large data set with support vector machines, radial basis neural networks and multiple linear regression.

    Science.gov (United States)

    Chen, Hai-Feng

    2009-08-01

    Oil/water partition coefficient (log P) is one of the key points for lead compound to be drug. In silico log P models based solely on chemical structures have become an important part of modern drug discovery. Here, we report support vector machines, radial basis function neural networks, and multiple linear regression methods to investigate the correlation between partition coefficient and physico-chemical descriptors for a large data set of compounds. The correlation coefficient r(2) between experimental and predicted log P for training and test sets by support vector machines, radial basis function neural networks, and multiple linear regression is 0.92, 0.90, and 0.88, respectively. The results show that non-linear support vector machines derives statistical models that have better prediction ability than those of radial basis function neural networks and multiple linear regression methods. This indicates that support vector machines can be used as an alternative modeling tool for quantitative structure-property/activity relationships studies.

  1. 47 CFR 54.701 - Administrator of universal service support mechanisms.

    Science.gov (United States)

    2010-10-01

    ... in connection with the high cost and low income support mechanism, the interstate access universal... 47 Telecommunication 3 2010-10-01 2010-10-01 false Administrator of universal service support... CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Administration § 54.701 Administrator of universal service...

  2. Mechanism of financial support of education: legislative basis of power distribution

    Directory of Open Access Journals (Sweden)

    O. S. Kotsovska

    2014-11-01

    Full Text Available The article studies the legislative basis of power distribution as a basic component of the mechanism of financial support of education at the regional level. Budgetary expenditure on education has been analyzed. It has been grounded and proposed to transfer the authority of financial support of education to appropriate regional and district administrations within the frameworks of decentralisation.

  3. Neural Mechanisms of Temporomandibular Joint and Masticatory Muscle Pain: A Possible Role for Peripheral Glutamate Receptor Mechanisms

    Directory of Open Access Journals (Sweden)

    David K Lam

    2005-01-01

    Full Text Available The purpose of the present review is to correlate recent knowledge of the role of peripheral ionotropic glutamate receptors in the temporomandibular joint and muscle pain from animal and human experimental pain models with findings in patients. Chronic pain is common, and many people suffer from chronic pain conditions involving deep craniofacial tissues such as temporomandibular disorders or fibromyalgia. Animal and human studies have indicated that the activation of peripheral ionotropic glutamate receptors in deep craniofacial tissues may contribute to muscle and temporomandibular joint pain and that sex differences in the activation of glutamate receptors may be involved in the female predominance in temporomandibular disorders and fibromyalgia. A peripheral mechanism involving autocrine and/or paracrine regulation of nociceptive neuronal excitability via injury or inflammation-induced release of glutamate into peripheral tissues that may contribute to the development of craniofacial pain is proposed.

  4. In search of neural mechanisms of mirror neuron dysfunction in schizophrenia: resting state functional connectivity approach.

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    Zaytseva, Yuliya; Bendova, Marie; Garakh, Zhanna; Tintera, Jaroslav; Rydlo, Jan; Spaniel, Filip; Horacek, Jiri

    2015-09-01

    It has been repeatedly shown that schizophrenia patients have immense alterations in goal-directed behaviour, social cognition, and social interactions, cognitive abilities that are presumably driven by the mirror neurons system (MNS). However, the neural bases of these deficits still remain unclear. Along with the task-related fMRI and EEG research tapping into the mirror neuron system, the characteristics of the resting state activity in the particular areas that encompass mirror neurons might be of interest as they obviously determine the baseline of the neuronal activity. Using resting state fMRI, we investigated resting state functional connectivity (FC) in four predefined brain structures, ROIs (inferior frontal gyrus, superior parietal lobule, premotor cortex and superior temporal gyrus), known for their mirror neurons activity, in 12 patients with first psychotic episode and 12 matched healthy individuals. As a specific hypothesis, based on the knowledge of the anatomical inputs of thalamus to all preselected ROIs, we have investigated the FC between thalamus and the ROIs. Of all ROIs included, seed-to-voxel connectivity analysis revealed significantly decreased FC only in left posterior superior temporal gyrus (STG) and the areas in visual cortex and cerebellum in patients as compared to controls. Using ROI-to-ROI analysis (thalamus and selected ROIs), we have found an increased FC of STG and bilateral thalamus whereas the FC of these areas was decreased in controls. Our results suggest that: (1) schizophrenia patients exhibit FC of STG which corresponds to the previously reported changes of superior temporal gyrus in schizophrenia and might contribute to the disturbances of specific functions, such as emotional processing or spatial awareness; (2) as the thalamus plays a pivotal role in the sensory gating, providing the filtering of the redundant stimulation, the observed hyperconnectivity between the thalami and the STGs in patients with schizophrenia

  5. Neural mechanisms underlying catastrophic failure in human-machine interaction during aerial navigation

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    Saproo, Sameer; Shih, Victor; Jangraw, David C.; Sajda, Paul

    2016-12-01

    Objective. We investigated the neural correlates of workload buildup in a fine visuomotor task called the boundary avoidance task (BAT). The BAT has been known to induce naturally occurring failures of human-machine coupling in high performance aircraft that can potentially lead to a crash—these failures are termed pilot induced oscillations (PIOs). Approach. We recorded EEG and pupillometry data from human subjects engaged in a flight BAT simulated within a virtual 3D environment. Main results. We find that workload buildup in a BAT can be successfully decoded from oscillatory features in the electroencephalogram (EEG). Information in delta, theta, alpha, beta, and gamma spectral bands of the EEG all contribute to successful decoding, however gamma band activity with a lateralized somatosensory topography has the highest contribution, while theta band activity with a fronto-central topography has the most robust contribution in terms of real-world usability. We show that the output of the spectral decoder can be used to predict PIO susceptibility. We also find that workload buildup in the task induces pupil dilation, the magnitude of which is significantly correlated with the magnitude of the decoded EEG signals. These results suggest that PIOs may result from the dysregulation of cortical networks such as the locus coeruleus (LC)—anterior cingulate cortex (ACC) circuit. Significance. Our findings may generalize to similar control failures in other cases of tight man-machine coupling where gains and latencies in the control system must be inferred and compensated for by the human operators. A closed-loop intervention using neurophysiological decoding of workload buildup that targets the LC-ACC circuit may positively impact operator performance in such situations.

  6. Folate receptor 1 is necessary for neural plate cell apical constriction during Xenopus neural tube formation.

    Science.gov (United States)

    Balashova, Olga A; Visina, Olesya; Borodinsky, Laura N

    2017-04-15

    Folate supplementation prevents up to 70% of neural tube defects (NTDs), which result from a failure of neural tube closure during embryogenesis. The elucidation of the mechanisms underlying folate action has been challenging. This study introduces Xenopus laevis as a model to determine the cellular and molecular mechanisms involved in folate action during neural tube formation. We show that knockdown of folate receptor 1 (Folr1; also known as FRα) impairs neural tube formation and leads to NTDs. Folr1 knockdown in neural plate cells only is necessary and sufficient to induce NTDs. Folr1-deficient neural plate cells fail to constrict, resulting in widening of the neural plate midline and defective neural tube closure. Pharmacological inhibition of folate action by methotrexate during neurulation induces NTDs by inhibiting folate interaction with its uptake systems. Our findings support a model in which the folate receptor interacts with cell adhesion molecules, thus regulating the apical cell membrane remodeling and cytoskeletal dynamics necessary for neural plate folding. Further studies in this organism could unveil novel cellular and molecular events mediated by folate and lead to new ways of preventing NTDs. © 2017. Published by The Company of Biologists Ltd.

  7. Both high level pressure support ventilation and controlled mechanical ventilation induce diaphragm dysfunction and atrophy.

    Science.gov (United States)

    Hudson, Matthew B; Smuder, Ashley J; Nelson, W Bradley; Bruells, Christian S; Levine, Sanford; Powers, Scott K

    2012-04-01

    Previous workers have demonstrated that controlled mechanical ventilation results in diaphragm inactivity and elicits a rapid development of diaphragm weakness as a result of both contractile dysfunction and fiber atrophy. Limited data exist regarding the impact of pressure support ventilation, a commonly used mode of mechanical ventilation-that permits partial mechanical activity of the diaphragm-on diaphragm structure and function. We carried out the present study to test the hypothesis that high-level pressure support ventilation decreases the diaphragm pathology associated with CMV. Sprague-Dawley rats were randomly assigned to one of the following five groups:1) control (no mechanical ventilation); 2) 12 hrs of controlled mechanical ventilation (12CMV); 3) 18 hrs of controlled mechanical ventilation (18CMV); 4) 12 hrs of pressure support ventilation (12PSV); or 5) 18 hrs of pressure support ventilation (18PSV). We carried out the following measurements on diaphragm specimens: 4-hydroxynonenal-a marker of oxidative stress, active caspase-3 (casp-3), active calpain-1 (calp-1), fiber type cross-sectional area, and specific force (sp F). Compared with the control, both 12PSV and 18PSV promoted a significant decrement in diaphragmatic specific force production, but to a lesser degree than 12CMV and 18CMV. Furthermore, 12CMV, 18PSV, and 18CMV resulted in significant atrophy in all diaphragm fiber types as well as significant increases in a biomarker of oxidative stress (4-hydroxynonenal) and increased proteolytic activity (20S proteasome, calpain-1, and caspase-3). Furthermore, although no inspiratory effort occurs during controlled mechanical ventilation, it was observed that pressure support ventilation resulted in large decrement, approximately 96%, in inspiratory effort compared with spontaneously breathing animals. High levels of prolonged pressure support ventilation promote diaphragmatic atrophy and contractile dysfunction. Furthermore, similar to controlled

  8. The effect of combined mechanism ankle support on postural control of patients with chronic ankle instability.

    Science.gov (United States)

    Hadadi, Mohammad; Ebrahimi, Ismaeil; Mousavi, Mohammad Ebrahim; Aminian, Gholamreza; Esteki, Ali; Rahgozar, Mehdi

    2017-02-01

    Chronic ankle instability is associated with neuromechanical changes and poor postural stability. Despite variety of mechanisms of foot and ankle orthoses, almost none apply comprehensive mechanisms to improve postural control in all subgroups of chronic ankle instability patients. The purpose of this study was to investigate the effect of an ankle support implementing combined mechanisms to improve postural control in chronic ankle instability patients. Cross-sectional study. An ankle support with combined mechanism was designed based on most effective action mechanisms of foot and ankle orthoses. The effect of this orthosis on postural control was evaluated in 20 participants with chronic ankle instability and 20 matched healthy participants. The single-limb stance balance test was measured in both groups with and without the new orthosis using a force platform. The results showed that application of combined mechanism ankle support significantly improved all postural sway parameters in chronic ankle instability patients. There were no differences in means of investigated parameters with and without the orthosis in the healthy group. No statistically significant differences were found in postural sway between chronic ankle instability patients and healthy participants after applying the combined mechanism ankle support. The combined mechanism ankle support is effective in improving static postural control of chronic ankle instability patients to close to the postural sway of healthy individual. the orthosis had no adverse effects on balance performance of healthy individuals. Clinical relevance Application of the combined mechanism ankle support for patients with chronic ankle instability is effective in improving static balance. This may be helpful in reduction of recurrence of ankle sprain although further research about dynamic conditions is needed.

  9. Individual Differences in Neural Mechanisms of Selective Auditory Attention in Preschoolers from Lower Socioeconomic Status Backgrounds: An Event-Related Potentials Study

    Science.gov (United States)

    Isbell, Elif; Wray, Amanda Hampton; Neville, Helen J.

    2016-01-01

    Selective attention, the ability to enhance the processing of particular input while suppressing the information from other concurrent sources, has been postulated to be a foundational skill for learning and academic achievement. The neural mechanisms of this foundational ability are both vulnerable and enhanceable in children from lower…

  10. Perceptual Surprise Improves Action Stopping by Nonselectively Suppressing Motor Activity via a Neural Mechanism for Motor Inhibition.

    Science.gov (United States)

    Dutra, Isabella C; Waller, Darcy A; Wessel, Jan R

    2018-02-07

    important in daily life (e.g., stopping to cross the street when a car approaches) and is severely impaired in many neuropsychiatric disorders. Therefore, finding ways to improve action stopping could aid adaptive behaviors in health and disease. Our current study shows that presenting unexpected sounds in stopping situations facilitates successful stopping. This improvement is specifically due to a surprise-related increase in a neural mechanism for motor inhibition, which rapidly suppresses the excitability of the motor system after unexpected events. These findings suggest a tight interaction between the neural systems for surprise processing and motor inhibition and yield a promising avenue for future research. Copyright © 2018 the authors 0270-6474/18/381482-11$15.00/0.

  11. RENEWABLE ENERGY SUPPORT MECHANISM IN TURKEY: FINANCIAL ANALYSIS AND RECOMMENDATIONS TO POLICYMAKERS

    Directory of Open Access Journals (Sweden)

    Mustafa GOZEN

    2014-04-01

    Full Text Available The Turkish Grand National Parliament passed a renewable energy promotion law that provides feed-in tariffs for electricity generation from renewable energy sources in 2005. This law was not attractive to investors due to the low level of feed-in tariffs. Then, in 2011, the promotion law was amended and a new support scheme integrated in the day-ahead market was introduced. Therefore, the main purpose of this article is to explain the new support mechanism, analyze it from the financial perspective, and discuss the related key issues and challenges. In addition, to further improve the support mechanism, some recommendations have been made to policymakers.

  12. Failing to learn from negative prediction errors: Obesity is associated with alterations in a fundamental neural learning mechanism.

    Science.gov (United States)

    Mathar, David; Neumann, Jane; Villringer, Arno; Horstmann, Annette

    2017-10-01

    Prediction errors (PEs) encode the difference between expected and actual action outcomes in the brain via dopaminergic modulation. Integration of these learning signals ensures efficient behavioral adaptation. Obesity has recently been linked to altered dopaminergic fronto-striatal circuits, thus implying impairments in cognitive domains that rely on its integrity. 28 obese and 30 lean human participants performed an implicit stimulus-response learning paradigm inside an fMRI scanner. Computational modeling and psycho-physiological interaction (PPI) analysis was utilized for assessing PE-related learning and associated functional connectivity. We show that human obesity is associated with insufficient incorporation of negative PEs into behavioral adaptation even in a non-food context, suggesting differences in a fundamental neural learning mechanism. Obese subjects were less efficient in using negative PEs to improve implicit learning performance, despite proper coding of PEs in striatum. We further observed lower functional coupling between ventral striatum and supplementary motor area in obese subjects subsequent to negative PEs. Importantly, strength of functional coupling predicted task performance and negative PE utilization. These findings show that obesity is linked to insufficient behavioral adaptation specifically in response to negative PEs, and to associated alterations in function and connectivity within the fronto-striatal system. Recognition of neural differences as a central characteristic of obesity hopefully paves the way to rethink established intervention strategies: Differential behavioral sensitivity to negative and positive PEs should be considered when designing intervention programs. Measures relying on penalization of unwanted behavior may prove less effective in obese subjects than alternative approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Association of Irritability and Anxiety With the Neural Mechanisms of Implicit Face Emotion Processing in Youths With Psychopathology.

    Science.gov (United States)

    Stoddard, Joel; Tseng, Wan-Ling; Kim, Pilyoung; Chen, Gang; Yi, Jennifer; Donahue, Laura; Brotman, Melissa A; Towbin, Kenneth E; Pine, Daniel S; Leibenluft, Ellen

    2017-01-01

    Psychiatric comorbidity complicates clinical care and confounds efforts to elucidate the pathophysiology of commonly occurring symptoms in youths. To our knowledge, few studies have simultaneously assessed the effect of 2 continuously distributed traits on brain-behavior relationships in children with psychopathology. To determine shared and unique effects of 2 major dimensions of child psychopathology, irritability and anxiety, on neural responses to facial emotions during functional magnetic resonance imaging. Cross-sectional functional magnetic resonance imaging study in a large, well-characterized clinical sample at a research clinic at the National Institute of Mental Health. The referred sample included youths ages 8 to 17 years, 93 youths with anxiety, disruptive mood dysregulation, and/or attention-deficit/hyperactivity disorders and 22 healthy youths. The child's irritability and anxiety were rated by both parent and child on the Affective Reactivity Index and Screen for Child Anxiety Related Disorders, respectively. Using functional magnetic resonance imaging, neural response was measured across the brain during gender labeling of varying intensities of angry, happy, or fearful face emotions. In mixed-effects analyses, the shared and unique effects of irritability and anxiety were tested on amygdala functional connectivity and activation to face emotions. The mean (SD) age of participants was 13.2 (2.6) years; of the 115 included, 64 were male. Irritability and/or anxiety influenced amygdala connectivity to the prefrontal and temporal cortex. Specifically, irritability and anxiety jointly influenced left amygdala to left medial prefrontal cortex connectivity during face emotion viewing (F4,888 = 9.20; P emotions in several areas (F2, 888 ≥ 13.45; all P emotion dysregulation when very anxious and irritable youth process threat-related faces. Activation in the ventral visual circuitry suggests a mechanism through which signals of social approach

  14. Application of Artificial Neural Network and Support Vector Machines in Predicting Metabolizable Energy in Compound Feeds for Pigs

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    Hamed Ahmadi

    2017-06-01

    Full Text Available BackgroundIn the nutrition literature, there are several reports on the use of artificial neural network (ANN and multiple linear regression (MLR approaches for predicting feed composition and nutritive value, while the use of support vector machines (SVM method as a new alternative approach to MLR and ANN models is still not fully investigated.MethodsThe MLR, ANN, and SVM models were developed to predict metabolizable energy (ME content of compound feeds for pigs based on the German energy evaluation system from analyzed contents of crude protein (CP, ether extract (EE, crude fiber (CF, and starch. A total of 290 datasets from standardized digestibility studies with compound feeds was provided from several institutions and published papers, and ME was calculated thereon. Accuracy and precision of developed models were evaluated, given their produced prediction values.ResultsThe results revealed that the developed ANN [R2 = 0.95; root mean square error (RMSE = 0.19 MJ/kg of dry matter] and SVM (R2 = 0.95; RMSE = 0.21 MJ/kg of dry matter models produced better prediction values in estimating ME in compound feed than those produced by conventional MLR (R2 = 0.89; RMSE = 0.27 MJ/kg of dry matter.ConclusionThe developed ANN and SVM models produced better prediction values in estimating ME in compound feed than those produced by conventional MLR; however, there were not obvious differences between performance of ANN and SVM models. Thus, SVM model may also be considered as a promising tool for modeling the relationship between chemical composition and ME of compound feeds for pigs. To provide the readers and nutritionist with the easy and rapid tool, an Excel® calculator, namely, SVM_ME_pig, was created to predict the metabolizable energy values in compound feeds for pigs using developed support vector machine model.

  15. A novel mechanism for switching a neural system from one state to another

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    Chethan Pandarinath

    2010-03-01

    Full Text Available An animal’s ability to rapidly adjust to new conditions is essential to its survival. The nervous system, then, must be built with the flexibility to adjust, or shift, its processing capabilities on the fly. To understand how this flexibility comes about, we tracked a well-known behavioral shift, a visual integration shift, down to its underlying circuitry, and found that it is produced by a novel mechanism – a change in gap junction coupling that can turn a cell class on and off. The results showed that the turning on and off of a cell class shifted the circuit’s behavior from one state to another, and, likewise, the animal’s behavior. The widespread presence of similar gap junction-coupled networks in the brain suggests that this mechanism may underlie other behavioral shifts as well.

  16. Tissue heterogeneity as a mechanism for localized neural stimulation by applied electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, P C [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon (Portugal); Correia, L [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon (Portugal); Salvador, R [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon (Portugal); Basser, P J [Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD 20892-1428 (United States)

    2007-09-21

    We investigate the heterogeneity of electrical conductivity as a new mechanism to stimulate excitable tissues via applied electric fields. In particular, we show that stimulation of axons crossing internal boundaries can occur at boundaries where the electric conductivity of the volume conductor changes abruptly. The effectiveness of this and other stimulation mechanisms was compared by means of models and computer simulations in the context of transcranial magnetic stimulation. While, for a given stimulation intensity, the largest membrane depolarization occurred where an axon terminates or bends sharply in a high electric field region, a slightly smaller membrane depolarization, still sufficient to generate action potentials, also occurred at an internal boundary where the conductivity jumped from 0.143 S m{sup -1} to 0.333 S m{sup -1}, simulating a white-matter-grey-matter interface. Tissue heterogeneity can also give rise to local electric field gradients that are considerably stronger and more focal than those impressed by the stimulation coil and that can affect the membrane potential, albeit to a lesser extent than the two mechanisms mentioned above. Tissue heterogeneity may play an important role in electric and magnetic 'far-field' stimulation.

  17. Lifelong bilingualism and neural reserve against Alzheimer's disease: a review of findings and potential mechanisms.

    Science.gov (United States)

    Gold, Brian T

    2015-03-15

    Alzheimer's disease (AD) is a progressive brain disorder that initially affects medial temporal lobe circuitry and memory functions. Current drug treatments have only modest effects on the symptomatic course of the disease. In contrast, a growing body of evidence suggests that lifelong bilingualism may delay the onset of clinical AD symptoms by several years. The purpose of the present review is to summarize evidence for bilingualism as a reserve variable against AD and discuss potential underlying neurocognitive mechanisms. Evidence is reviewed suggesting that bilingualism may delay clinical AD symptoms by protecting frontostriatal and frontoparietal executive control circuitry rather than medial temporal lobe memory circuitry. Cellular and molecular mechanisms that may contribute to bilingual cognitive reserve effects are discussed, including those that may affect neuronal metabolic functions, dynamic neuronal-glial interactions, vascular factors, myelin structure and neurochemical signaling. Future studies that may test some of these potential mechanisms of bilingual CR effects are proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. A feed-forward spinal cord glycinergic neural circuit gates mechanical allodynia.

    Science.gov (United States)

    Lu, Yan; Dong, Hailong; Gao, Yandong; Gong, Yuanyuan; Ren, Yingna; Gu, Nan; Zhou, Shudi; Xia, Nan; Sun, Yan-Yan; Ji, Ru-Rong; Xiong, Lize

    2013-09-01

    Neuropathic pain is characterized by mechanical allodynia induced by low-threshold myelinated Aβ-fiber activation. The original gate theory of pain proposes that inhibitory interneurons in the lamina II of the spinal dorsal horn (DH) act as "gate control" units for preventing the interaction between innocuous and nociceptive signals. However, our understanding of the neuronal circuits underlying pain signaling and modulation in the spinal DH is incomplete. Using a rat model, we have shown that the convergence of glycinergic inhibitory and excitatory Aβ-fiber inputs onto PKCγ+ neurons in the superficial DH forms a feed-forward inhibitory circuit that prevents Aβ input from activating the nociceptive pathway. This feed-forward inhibition was suppressed following peripheral nerve injury or glycine blockage, leading to inappropriate induction of action potential outputs in the nociceptive pathway by Aβ-fiber stimulation. Furthermore, spinal blockage of glycinergic synaptic transmission in vivo induced marked mechanical allodynia. Our findings identify a glycinergic feed-forward inhibitory circuit that functions as a gate control to separate the innocuous mechanoreceptive pathway and the nociceptive pathway in the spinal DH. Disruption of this glycinergic inhibitory circuit after peripheral nerve injury has the potential to elicit mechanical allodynia, a cardinal symptom of neuropathic pain.

  19. Mechanisms to Support Private Enterprise in the System of State Capitalism

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    Bogoutdinov Boris, B.

    2016-07-01

    Full Text Available Some of the main problems in developing the institute of private enterprise in Russia are ineffectiveness of government support and lack of competence among the entrepreneurs themselves. In the paper the author analyzes the existing mechanisms of business development for small and mediumsized businesses, which in case of effective implementation will drive up the share of self employment, tax revenue and quality of life. The aim of the paper is to develop methods and tools for development of private enterprise institute pursuing the task of forming a highly developed modern society. The mechanisms of support for small entrepreneurs in China, as well as problems of search funds and mittelshtands mechanisms were considered. The practical significance lies in the analysis of the existing enabling mechanism for small and medium-sized businesses with the purpose of development of new mechanisms of transformation of economic systems in Russia.

  20. Rules and mechanisms for efficient two-stage learning in neural circuits.

    Science.gov (United States)

    Teşileanu, Tiberiu; Ölveczky, Bence; Balasubramanian, Vijay

    2017-04-04

    Trial-and-error learning requires evaluating variable actions and reinforcing successful variants. In songbirds, vocal exploration is induced by LMAN, the output of a basal ganglia-related circuit that also contributes a corrective bias to the vocal output. This bias is gradually consolidated in RA, a motor cortex analogue downstream of LMAN. We develop a new model of such two-stage learning. Using stochastic gradient descent, we derive how the activity in 'tutor' circuits ( e.g., LMAN) should match plasticity mechanisms in 'student' circuits ( e.g., RA) to achieve efficient learning. We further describe a reinforcement learning framework through which the tutor can build its teaching signal. We show that mismatches between the tutor signal and the plasticity mechanism can impair learning. Applied to birdsong, our results predict the temporal structure of the corrective bias from LMAN given a plasticity rule in RA. Our framework can be applied predictively to other paired brain areas showing two-stage learning.

  1. Development of neural mechanisms of conflict and error processing during childhood: Implications for self-regulation

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    Purificación eCheca

    2014-04-01

    Full Text Available Regulation of thoughts and behavior requires attention, particularly when there is conflict between alternative responses or when errors are to be prevented or corrected. Conflict monitoring and error processing are functions of the executive attention network, a neurocognitive system that greatly matures during childhood. In this study, we examined the development of brain mechanisms underlying conflict and error processing with event-related potentials (ERPs, and explored the relationship between brain function and individual differences in the ability to self-regulate behavior. Three groups of children aged 4 to 6, 7 to 9, and 10 to 13 years, and a group of adults performed a child-friendly version of the flanker task while ERPs were registered. Marked developmental changes were observed in both conflict processing and brain reactions to errors. After controlling by age, higher self-regulation skills are associated with smaller amplitude of the conflict effect but greater amplitude of the error-related negativity. Additionally, we found that electrophysiological measures of conflict and error monitoring predict individual differences in impulsivity and the capacity to delay gratification. These findings inform of brain mechanisms underlying the development of cognitive control and self-regulation.

  2. Tinnitus Neural Mechanisms and Structural Changes in the Brain: The Contribution of Neuroimaging Research

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    Simonetti, Patricia

    2015-03-01

    Full Text Available Introduction Tinnitus is an abnormal perception of sound in the absence of an external stimulus. Chronic tinnitus usually has a high impact in many aspects of patients' lives, such as emotional stress, sleep disturbance, concentration difficulties, and so on. These strong reactions are usually attributed to central nervous system involvement. Neuroimaging has revealed the implication of brain structures in the auditory system. Objective This systematic review points out neuroimaging studies that contribute to identifying the structures involved in the pathophysiological mechanism of generation and persistence of various forms of tinnitus. Data Synthesis Functional imaging research reveals that tinnitus perception is associated with the involvement of the nonauditory brain areas, including the front parietal area; the limbic system, which consists of the anterior cingulate cortex, anterior insula, and amygdala; and the hippocampal and parahippocampal area. Conclusion The neuroimaging research confirms the involvement of the mechanisms of memory and cognition in the persistence of perception, anxiety, distress, and suffering associated with tinnitus.

  3. An artificial neural network model for the prediction of mechanical and barrier properties of biodegradable films.

    Science.gov (United States)

    Nobrega, Marcelo Medre; Bona, Evandro; Yamashita, Fabio

    2013-10-01

    Nowadays, the production of biodegradable starch-based films is of great interest because of the growing environmental concerns regarding pollution and the need to reduce dependence on the plastics industry. A broad view of the role of different components, added to starch-based films to improve their properties, is required to guide the future development. The self-organizing maps (SOMs) provide comparisons that initially were complicated due to the large volume of the data. Furthermore, the construction of a model capable of predicting the mechanical and barrier properties of these films will accelerate the development of films with improved characteristics. The water vapor permeability (WVP) analysis using the SOM algorithm showed that the presence of glycerol is very important for films with low amounts of poly (butylene adipate co-terephthalate) and confirms the role of the equilibrium relative humidity in the determination of WVP. Considering the mechanical properties, the SOM analysis emphasizes the important role of poly (butylene adipate co-terephthalate) in thermoplastic starch based films. The properties of biodegradable films were predicted and optimized by using a multilayer perceptron coupled with a genetic algorithm, presenting a great correlation between the experimental and theoretical values with a maximum error of 24%. To improve the response of the model and to ensure the compatibility of the components more information will be necessary. © 2013.

  4. Development of neural mechanisms of conflict and error processing during childhood: implications for self-regulation

    Science.gov (United States)

    Checa, Purificación; Castellanos, M. C.; Abundis-Gutiérrez, Alicia; Rosario Rueda, M.

    2014-01-01

    Regulation of thoughts and behavior requires attention, particularly when there is conflict between alternative responses or when errors are to be prevented or corrected. Conflict monitoring and error processing are functions of the executive attention network, a neurocognitive system that greatly matures during childhood. In this study, we examined the development of brain mechanisms underlying conflict and error processing with event-related potentials (ERPs), and explored the relationship between brain function and individual differences in the ability to self-regulate behavior. Three groups of children aged 4–6, 7–9, and 10–13 years, and a group of adults performed a child-friendly version of the flanker task while ERPs were registered. Marked developmental changes were observed in both conflict processing and brain reactions to errors. After controlling by age, higher self-regulation skills are associated with smaller amplitude of the conflict effect but greater amplitude of the error-related negativity. Additionally, we found that electrophysiological measures of conflict and error monitoring predict individual differences in impulsivity and the capacity to delay gratification. These findings inform of brain mechanisms underlying the development of cognitive control and self-regulation. PMID:24795676

  5. Artificial intelligence: Neural network model as the multidisciplinary team member in clinical decision support to avoid medical mistakes

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    Igor Vyacheslavovich Buzaev

    2016-09-01

    Full Text Available Objective: The continuous uninterrupted feedback system is the essential part of any well-organized system. We propose aLYNX concept that is a possibility to use an artificial intelligence algorithm or a neural network model in decision-making system so as to avoid possible mistakes and to remind the doctors to review tactics once more in selected cases. Method: aLYNX system includes: registry with significant factors, decisions and results; machine learning process based on this registry data; the use of the machine learning results as the adviser. We show a possibility to build a computer adviser with a neural network model for making a choice between coronary aortic bypass surgery (CABG and percutaneous coronary intervention (PCI in order to achieve a higher 5-year survival rate in patients with angina based on the experience of 5107 patients. Results: The neural network was trained by 4679 patients who achieved 5-year survival. Among them, 2390 patients underwent PCI and 2289 CABG. After training, the correlation coefficient (r of the network was 0.74 for training, 0.67 for validation, 0.71 for test and 0.73 for total. Simulation of the neural network function has been performed after training in the two groups of patients with known 5-year outcome. The disagreement rate was significantly higher in the dead patient group than that in the survivor group between neural network model and heart team [16.8% (787/4679 vs. 20.3% (87/428, P = 0.065]. Conclusion: The study shows the possibility to build a computer adviser with a neural network model for making a choice between CABG and PCI in order to achieve a higher 5-year survival rate in patients with angina. Keywords: Coronary artery bypass grafting, Percutaneous coronary intervention, Artificial intelligence, Decision making

  6. Artificial intelligence: Neural network model as the multidisciplinary team member in clinical decision support to avoid medical mistakes.

    Science.gov (United States)

    Buzaev, Igor Vyacheslavovich; Plechev, Vladimir Vyacheslavovich; Nikolaeva, Irina Evgenievna; Galimova, Rezida Maratovna

    2016-09-01

    The continuous uninterrupted feedback system is the essential part of any well-organized system. We propose aLYNX concept that is a possibility to use an artificial intelligence algorithm or a neural network model in decision-making system so as to avoid possible mistakes and to remind the doctors to review tactics once more in selected cases. aLYNX system includes: registry with significant factors, decisions and results; machine learning process based on this registry data; the use of the machine learning results as the adviser. We show a possibility to build a computer adviser with a neural network model for making a choice between coronary aortic bypass surgery (CABG) and percutaneous coronary intervention (PCI) in order to achieve a higher 5-year survival rate in patients with angina based on the experience of 5107 patients. The neural network was trained by 4679 patients who achieved 5-year survival. Among them, 2390 patients underwent PCI and 2289 CABG. After training, the correlation coefficient ( r ) of the network was 0.74 for training, 0.67 for validation, 0.71 for test and 0.73 for total. Simulation of the neural network function has been performed after training in the two groups of patients with known 5-year outcome. The disagreement rate was significantly higher in the dead patient group than that in the survivor group between neural network model and heart team [16.8% (787/4679) vs. 20.3% (87/428), P  = 0.065)]. The study shows the possibility to build a computer adviser with a neural network model for making a choice between CABG and PCI in order to achieve a higher 5-year survival rate in patients with angina.

  7. Behavioral and neural Darwinism: selectionist function and mechanism in adaptive behavior dynamics.

    Science.gov (United States)

    McDowell, J J

    2010-05-01

    An evolutionary theory of behavior dynamics and a theory of neuronal group selection share a common selectionist framework. The theory of behavior dynamics instantiates abstractly the idea that behavior is selected by its consequences. It implements Darwinian principles of selection, reproduction, and mutation to generate adaptive behavior in virtual organisms. The behavior generated by the theory has been shown to be quantitatively indistinguishable from that of live organisms. The theory of neuronal group selection suggests a mechanism whereby the abstract principles of the evolutionary theory may be implemented in the nervous systems of biological organisms. According to this theory, groups of neurons subserving behavior may be selected by synaptic modifications that occur when the consequences of behavior activate value systems in the brain. Together, these theories constitute a framework for a comprehensive account of adaptive behavior that extends from brain function to the behavior of whole organisms in quantitative detail. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  8. Neurocognitive mechanisms underlying social learning in infancy: infants' neural processing of the effects of others' actions.

    Science.gov (United States)

    Paulus, Markus; Hunnius, Sabine; Bekkering, Harold

    2013-10-01

    Social transmission of knowledge is one of the reasons for human evolutionary success, and it has been suggested that already human infants possess eminent social learning abilities. However, nothing is known about the neurocognitive mechanisms that subserve infants' acquisition of novel action knowledge through the observation of other people's actions and their consequences in the physical world. In an electroencephalogram study on social learning in infancy, we demonstrate that 9-month-old infants represent the environmental effects of others' actions in their own motor system, although they never achieved these effects themselves before. The results provide first insights into the neurocognitive basis of human infants' unique ability for social learning of novel action knowledge.

  9. How social is error observation? The neural mechanisms underlying the observation of human and machine errors.

    Science.gov (United States)

    Desmet, Charlotte; Deschrijver, Eliane; Brass, Marcel

    2014-04-01

    Recently, it has been shown that the medial prefrontal cortex (MPFC) is involved in error execution as well as error observation. Based on this finding, it has been argued that recognizing each other's mistakes might rely on motor simulation. In the current functional magnetic resonance imaging (fMRI) study, we directly tested this hypothesis by investigating whether medial prefrontal activity in error observation is restricted to situations that enable simulation. To this aim, we compared brain activity related to the observation of errors that can be simulated (human errors) with brain activity related to errors that cannot be simulated (machine errors). We show that medial prefrontal activity is not only restricted to the observation of human errors but also occurs when observing errors of a machine. In addition, our data indicate that the MPFC reflects a domain general mechanism of monitoring violations of expectancies.

  10. Water deprivation and the double- depletion hypothesis: common neural mechanisms underlie thirst and salt appetite

    Directory of Open Access Journals (Sweden)

    L.A. Jr De Luca

    2007-05-01

    Full Text Available Water deprivation-induced thirst is explained by the double-depletion hypothesis, which predicts that dehydration of the two major body fluid compartments, the extracellular and intracellular compartments, activates signals that combine centrally to induce water intake. However, sodium appetite is also elicited by water deprivation. In this brief review, we stress the importance of the water-depletion and partial extracellular fluid-repletion protocol which permits the distinction between sodium appetite and thirst. Consistent enhancement or a de novo production of sodium intake induced by deactivation of inhibitory nuclei (e.g., lateral parabrachial nucleus or hormones (oxytocin, atrial natriuretic peptide, in water-deprived, extracellular-dehydrated or, contrary to tradition, intracellular-dehydrated rats, suggests that sodium appetite and thirst share more mechanisms than previously thought. Water deprivation has physiological and health effects in humans that might be related to the salt craving shown by our species.

  11. The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

    Science.gov (United States)

    Zhang, Wen; Zeng, Langqing; Liu, Yanjie; Pan, Yao; Zhang, Wei; Zhang, Changqing; Zeng, Bingfang; Chen, Yunfeng

    2014-01-01

    The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures. Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (Pproximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P ≤ 0.0207). Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

  12. Comparing artificial neural networks, general linear models and support vector machines in building predictive models for small interfering RNAs.

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    Kyle A McQuisten

    Full Text Available BACKGROUND: Exogenous short interfering RNAs (siRNAs induce a gene knockdown effect in cells by interacting with naturally occurring RNA processing machinery. However not all siRNAs induce this effect equally. Several heterogeneous kinds of machine learning techniques and feature sets have been applied to modeling siRNAs and their abilities to induce knockdown. There is some growing agreement to which techniques produce maximally predictive models and yet there is little consensus for methods to compare among predictive models. Also, there are few comparative studies that address what the effect of choosing learning technique, feature set or cross validation approach has on finding and discriminating among predictive models. PRINCIPAL FINDINGS: Three learning techniques were used to develop predictive models for effective siRNA sequences including Artificial Neural Networks (ANNs, General Linear Models (GLMs and Support Vector Machines (SVMs. Five feature mapping methods were also used to generate models of siRNA activities. The 2 factors of learning technique and feature mapping were evaluated by complete 3x5 factorial ANOVA. Overall, both learning techniques and feature mapping contributed significantly to the observed variance in predictive models, but to differing degrees for precision and accuracy as well as across different kinds and levels of model cross-validation. CONCLUSIONS: The methods presented here provide a robust statistical framework to compare among models developed under distinct learning techniques and feature sets for siRNAs. Further comparisons among current or future modeling approaches should apply these or other suitable statistically equivalent methods to critically evaluate the performance of proposed models. ANN and GLM techniques tend to be more sensitive to the inclusion of noisy features, but the SVM technique is more robust under large numbers of features for measures of model precision and accuracy. Features

  13. [Indications and strategies in mechanical circulatory support : Rise of the machines?

    Science.gov (United States)

    Dashkevich, A; Michel, S; Hagl, C

    2017-09-04

    Terminal heart failure is an emerging problem with a continuously growing number of diseased patients worldwide. Because of the limited number of donor hearts, mechanical circulatory support is increasingly becoming an integral part of surgical treatment for end-stage heart failure, especially in patients deemed for destination therapy. Accurate patient selection, appropriate indication, and the optimal implantation time point guarantee a good outcome for these patients. This review article gives a systematic overview of the possible indication settings and treatment strategies for various patient groups in need of mechanical circulatory support.

  14. Application of hierarchical dissociated neural network in closed-loop hybrid system integrating biological and mechanical intelligence.

    Directory of Open Access Journals (Sweden)

    Yongcheng Li

    Full Text Available Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including 'random' and '4Q' (cultured neurons artificially divided into four interconnected parts neural network. Compared to the random cultures, the '4Q' cultures presented absolutely different activities, and the robot controlled by the '4Q' network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems.

  15. Application of hierarchical dissociated neural network in closed-loop hybrid system integrating biological and mechanical intelligence.

    Science.gov (United States)

    Li, Yongcheng; Sun, Rong; Zhang, Bin; Wang, Yuechao; Li, Hongyi

    2015-01-01

    Neural networks are considered the origin of intelligence in organisms. In this paper, a new design of an intelligent system merging biological intelligence with artificial intelligence was created. It was based on a neural controller bidirectionally connected to an actual mobile robot to implement a novel vehicle. Two types of experimental preparations were utilized as the neural controller including 'random' and '4Q' (cultured neurons artificially divided into four interconnected parts) neural network. Compared to the random cultures, the '4Q' cultures presented absolutely different activities, and the robot controlled by the '4Q' network presented better capabilities in search tasks. Our results showed that neural cultures could be successfully employed to control an artificial agent; the robot performed better and better with the stimulus because of the short-term plasticity. A new framework is provided to investigate the bidirectional biological-artificial interface and develop new strategies for a future intelligent system using these simplified model systems.

  16. Pictures of a thousand words: investigating the neural mechanisms of reading with extremely rapid event-related fMRI.

    Science.gov (United States)

    Yarkoni, Tal; Speer, Nicole K; Balota, David A; McAvoy, Mark P; Zacks, Jeffrey M

    2008-08-15

    Reading is one of the most important skills human beings can acquire, but has proven difficult to study naturalistically using functional magnetic resonance imaging (fMRI). We introduce a novel Event-Related Reading (ERR) fMRI approach that enables reliable estimation of the neural correlates of single-word processing during reading of rapidly presented narrative text (200-300 ms/word). Application to an fMRI experiment in which subjects read coherent narratives and made no overt responses revealed widespread effects of orthographic, phonological, contextual, and semantic variables on brain activation. Word-level variables predicted activity in classical language areas as well as the inferotemporal visual word form area, specifically supporting a role for the latter in mapping visual forms onto articulatory or acoustic representations. Additional analyses demonstrated that ERR results replicate across experiments and predict reading comprehension. The ERR approach represents a powerful and extremely flexible new approach for studying reading and language behavior with fMRI.

  17. The hybrid GLM-ICA investigation on the neural mechanism of acupoint ST36: an fMRI study.

    Science.gov (United States)

    Liu, Peng; Zhou, Guangyu; Zhang, Yi; Dong, Minghao; Qin, Wei; Yuan, Kai; Sun, Jinbo; Liu, Jixin; Liang, Jimin; von Deneen, Karen M; Liu, Yijun; Tian, Jie

    2010-08-02

    Ample clinical reports and neuroimaging studies have demonstrated that the acupuncture has sustained effects after manipulation. However, most previous fMRI studies of acupuncture have paid little attention to this issue, only investigating on the manipulation effects. In the current study, we attempted to explore both acupuncture effects, which have positive influence to therapeutic efficiency, to reveal the neural mechanism of acupuncture. This paper combined the conventional general linear model (GLM) and independent component analysis (ICA) to study the topography and the temporal feature of brain activity to detect the brain responses to stimulation at ST36 (Zusanli) and a sham acupoint. The results showed that the manipulation-related effects and the sustained acupuncture effects separately induced statistically significant increases/decreases in the cortical-subcortical areas, including the anterior cingulate cortex (ACC), ventrolateral prefrontal cortex (VLPFC), supplementary motor area (SMA) primary/secondary somatosensory cortex (SI/SII), occipital cortices and midbrain. Our findings suggested that the analgesia effects of ST36 integrated sophisticated physiological and psychological procedures. In addition, our results have shed light on methodology in acupuncture research. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  18. Neural mechanisms underlying the effects of face-based affective signals on memory for faces: a tentative model.

    Science.gov (United States)

    Tsukiura, Takashi

    2012-01-01

    In our daily lives, we form some impressions of other people. Although those impressions are affected by many factors, face-based affective signals such as facial expression, facial attractiveness, or trustworthiness are important. Previous psychological studies have demonstrated the impact of facial impressions on remembering other people, but little is known about the neural mechanisms underlying this psychological process. The purpose of this article is to review recent functional MRI (fMRI) studies to investigate the effects of face-based affective signals including facial expression, facial attractiveness, and trustworthiness on memory for faces, and to propose a tentative concept for understanding this affective-cognitive interaction. On the basis of the aforementioned research, three brain regions are potentially involved in the processing of face-based affective signals. The first candidate is the amygdala, where activity is generally modulated by both affectively positive and negative signals from faces. Activity in the orbitofrontal cortex (OFC), as the second candidate, increases as a function of perceived positive signals from faces; whereas activity in the insular cortex, as the third candidate, reflects a function of face-based negative signals. In addition, neuroscientific studies have reported that the three regions are functionally connected to the memory-related hippocampal regions. These findings suggest that the effects of face-based affective signals on memory for faces could be modulated by interactions between the regions associated with the processing of face-based affective signals and the hippocampus as a memory-related region.

  19. Risk-taking and social exclusion in adolescence: neural mechanisms underlying peer influences on decision-making.

    Science.gov (United States)

    Peake, Shannon J; Dishion, Thomas J; Stormshak, Elizabeth A; Moore, William E; Pfeifer, Jennifer H

    2013-11-15

    Social exclusion and risk-taking are both common experiences of concern in adolescence, yet little is known about how the two may be related at behavioral or neural levels. In this fMRI study, adolescents (N=27, 14 male, 14-17years-old) completed a series of tasks in the scanner assessing risky decision-making before and after an episode of social exclusion. In this particular context, exclusion was associated with greater behavioral risk-taking among adolescents with low self-reported resistance to peer influence (RPI). When making risky decisions after social exclusion, adolescents who had lower RPI exhibited higher levels of activity in the right temporoparietal junction (rTPJ), and this response in rTPJ was a significant mediator of the relationship between RPI and greater risk-taking after social exclusion. Lower RPI was also associated with lower levels of activity in lPFC during crashes following social exclusion, but unlike rTPJ this response in lPFC was not a significant mediator of the relationship between RPI and greater risk-taking after social exclusion. The results suggest that mentalizing and/or attentional mechanisms have a unique direct effect on adolescents' vulnerability to peer influence on risk-taking. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Multiobjective Optimization Design of Spinal Pedicle Screws Using Neural Networks and Genetic Algorithm: Mathematical Models and Mechanical Validation

    Directory of Open Access Journals (Sweden)

    Yongyut Amaritsakul

    2013-01-01

    Full Text Available Short-segment instrumentation for spine fractures is threatened by relatively high failure rates. Failure of the spinal pedicle screws including breakage and loosening may jeopardize the fixation integrity and lead to treatment failure. Two important design objectives, bending strength and pullout strength, may conflict with each other and warrant a multiobjective optimization study. In the present study using the three-dimensional finite element (FE analytical results based on an L25 orthogonal array, bending and pullout objective functions were developed by an artificial neural network (ANN algorithm, and the trade-off solutions known as Pareto optima were explored by a genetic algorithm (GA. The results showed that the knee solutions of the Pareto fronts with both high bending and pullout strength ranged from 92% to 94% of their maxima, respectively. In mechanical validation, the results of mathematical analyses were closely related to those of experimental tests with a correlation coefficient of −0.91 for bending and 0.93 for pullout (P<0.01 for both. The optimal design had significantly higher fatigue life (P<0.01 and comparable pullout strength as compared with commercial screws. Multiobjective optimization study of spinal pedicle screws using the hybrid of ANN and GA could achieve an ideal with high bending and pullout performances simultaneously.

  1. Mechanisms Underlying the Antiproliferative and Prodifferentiative Effects of Psoralen on Adult Neural Stem Cells via DNA Microarray

    Directory of Open Access Journals (Sweden)

    You Ning

    2013-01-01

    Full Text Available Adult neural stem cells (NSCs persist throughout life to replace mature cells that are lost during turnover, disease, or injury. The investigation of NSC creates novel treatments for central nervous system (CNS injuries and neurodegenerative disorders. The plasticity and reparative potential of NSC are regulated by different factors, which are critical for neurological regenerative medicine research. We investigated the effects of Psoralen, which is the mature fruit of Psoralea corylifolia L., on NSC behaviors and the underlying mechanisms. The self-renewal and proliferation of NSC were examined. We detected neuron- and/or astrocyte-specific markers using immunofluorescence and Western blotting, which could evaluate NSC differentiation. Psoralen treatment significantly inhibited neurosphere formation in a dose-dependent manner. Psoralen treatment increased the expression of the astrocyte-specific marker but decreased neuron-specific marker expression. These results suggested that Psoralen was a differentiation inducer in astrocyte. Differential gene expression following Psoralen treatment was screened using DNA microarray and confirmed by quantitative real-time PCR. Our microarray study demonstrated that Psoralen could effectively regulate the specific gene expression profile of NSC. The genes involved in the classification of cellular differentiation, proliferation, and metabolism, the transcription factors belonging to Ets family, and the hedgehog pathway may be closely related to the regulation.

  2. Multiobjective optimization design of spinal pedicle screws using neural networks and genetic algorithm: mathematical models and mechanical validation.

    Science.gov (United States)

    Amaritsakul, Yongyut; Chao, Ching-Kong; Lin, Jinn

    2013-01-01

    Short-segment instrumentation for spine fractures is threatened by relatively high failure rates. Failure of the spinal pedicle screws including breakage and loosening may jeopardize the fixation integrity and lead to treatment failure. Two important design objectives, bending strength and pullout strength, may conflict with each other and warrant a multiobjective optimization study. In the present study using the three-dimensional finite element (FE) analytical results based on an L25 orthogonal array, bending and pullout objective functions were developed by an artificial neural network (ANN) algorithm, and the trade-off solutions known as Pareto optima were explored by a genetic algorithm (GA). The results showed that the knee solutions of the Pareto fronts with both high bending and pullout strength ranged from 92% to 94% of their maxima, respectively. In mechanical validation, the results of mathematical analyses were closely related to those of experimental tests with a correlation coefficient of -0.91 for bending and 0.93 for pullout (P < 0.01 for both). The optimal design had significantly higher fatigue life (P < 0.01) and comparable pullout strength as compared with commercial screws. Multiobjective optimization study of spinal pedicle screws using the hybrid of ANN and GA could achieve an ideal with high bending and pullout performances simultaneously.

  3. Neural Mechanisms and Children's Intellectual Development: Multiple Impacts of Environmental Factors.

    Science.gov (United States)

    Takeuchi, Hikaru; Kawashima, Ryuta

    2016-12-01

    Human psychometric intelligence can predict a number of important social and academic outcomes. Substantial parts of the variances of human intelligence and the brain volume supporting those abilities are explained by environmental factors, and during childhood, human brains have higher plasticity and also 60% of variance of intelligence that is explained by environmental factors. Here, we review the representative environmental factors known to affect human intellectual development during each developmental stage. We describe what is (and what is not) being investigated to determine how these factors affect human brain development through analyses of volumetrical and cortical structures. In conclusion, environmental factors that affect children's intellectual development lead to three patterns of brain structural change. The first is global change in the brain structure, observed more often in the earlier phase of development. The second is structural changes concentrated in the medial prefrontal and adjacent areas and medial temporal areas, which are likely to be induced by stress in many cases. The third is sporadic region-specific change, likely to be primarily caused by use-dependent plasticity of the areas that is often observed in the later phase of development. These changes may underlie the alterations in children's intellectual development that is induced by environmental factors. © The Author(s) 2015.

  4. Virtual Reality to Maximize Function for Hand and Arm Rehabilitation: Exploration of Neural Mechanisms

    Science.gov (United States)

    MERIANS, Alma S.; TUNIK, Eugene; ADAMOVICH, Sergei V.

    2015-01-01

    Stroke patients report hand function as the most disabling motor deficit. Current evidence shows that learning new motor skills is essential for inducing functional neuroplasticity and functional recovery. Adaptive training paradigms that continually and interactively move a motor outcome closer to the targeted skill are important to motor recovery. Computerized virtual reality simulations when interfaced with robots, movement tracking and sensing glove systems are particularly adaptable, allowing for online and offline modifications of task based activities using the participant’s current performance and success rate. We have developed a second generation system that can exercise the hand and the arm together or in isolation and provides for both unilateral and bilateral hand and arm activities in three-dimensional space. We demonstrate that by providing haptic assistance for the hand and arm and adaptive anti-gravity support, the system can accommodate patients with lower level impairments. We hypothesize that combining training in VE with observation of motor actions can bring additional benefits. We present a proof of concept of a novel system that integrates interactive VE with functional neuroimaging to address this issue. Three components of this system are synchronized, the presentation of the visual display of the virtual hands, the collection of fMRI images and the collection of hand joint angles from the instrumented gloves. We show that interactive VEs can facilitate activation of brain areas during training by providing appropriately modified visual feedback. We predict that visual augmentation can become a tool to facilitate functional neuroplasticity. PMID:19592790

  5. Neural mechanisms of spatial- and feature-based attention: a quantitative analysis.

    Science.gov (United States)

    Stoppel, Christian Michael; Boehler, Carsten Nicolas; Sabelhaus, Clemens; Heinze, Hans-Jochen; Hopf, Jens Max; Schoenfeld, Mircea Ariel

    2007-11-21

    Attentional selection can be based on spatial locations, non-spatial stimulus features, or entire objects as integrated feature ensembles. Several studies reported attentional modulations in those regions that process the constituent features of the presented stimuli. Here we employed functional magnetic resonance imaging (fMRI) to directly compare the magnitude of space- and/or feature-based attentional modulations while subjects directed their attention to a particular color (red or green) of a transparent surface and at the same time to a spatial location (left or right visual field). The experimental design made it possible to disentangle and quantify the hemodynamic activity elicited by identical physical stimuli when attention was directed to spatial locations and/or stimulus features. The highest modulations were observed when the attentional selection was based on spatial location. Attended features also elicited a response increase relative to unattended features when their spatial location was attended. Importantly, at unattended locations, a response increase upon feature-based selection was observed in motion-sensitive but not in color-related areas. This suggests that compared to color, motion stimuli are more effective in capturing attention at unattended locations leading to a competitive advantage. These results support the idea of a high biological relevance of the feature motion in the visual world.

  6. FEATURES OF LONG-TERM MECHANICAL CIRCULATORY SUPPORT WITH CONTINUOUS-FLOW PUMP

    Directory of Open Access Journals (Sweden)

    G. P. Itkin

    2012-01-01

    Full Text Available In a review of the comparative analysis of methods and tools for long-term mechanical circulatory support with continuous flow and pulsatile flow implantable pumps. Particular attention is paid to the choice of the optimal modes of the operation of pumps based on the physical principles of the interaction between a the steady flow of blood to the pulsatile mechanics of the heart chambers. 

  7. Behavioral differences in aggressive children linked with neural mechanisms of emotion regulation.

    Science.gov (United States)

    Lewis, Marc D; Granic, Isabela; Lamm, Connie

    2006-12-01

    Children with aggressive behavior problems may have difficulties regulating negative emotions, resulting in harmful patterns of interpersonal behavior at home and in the schoolyard. Ventral and dorsal regions of the prefrontal cortex (PFC) have been associated with response inhibition and self-control-key components of emotion regulation. Our research program aims to explore differences among aggressive and normal children in the activation of these cortical regions during emotional episodes, to the extent possible using electrophysiological techniques, to identify diagnostic subtypes, gain insights into their interpersonal difficulties, and help develop effective treatment strategies. This report reviews several recent studies investigating individual and developmental differences in cortical mechanisms of emotion regulation, corresponding with different patterns of interpersonal behavior. Our methods include event-related potentials (ERPs) and cortical source modeling, using dense-array electroencephalography (EEG) technology, as well as videotaped observations of parent-child interactions, with both normal and aggressive children. By relating patterns of brain activation to observed behavioral differences, we find (i) a steady decrease in cortical activation subserving self-regulation across childhood and adolescence, (ii) different cortical activation patterns as well as behavioral constellations distinguishing subtypes of aggressive children, and (iii) robust correlations between the activation of cortical mediators of emotion regulation and flexibility in parent-child emotional communication in children referred for aggressive behavior problems. These findings point toward models of developmental psychopathology based on the interplay among biological, psychological, and social factors.

  8. Do horizontal saccadic eye movements increase interhemispheric coherence? Investigation of a hypothesized neural mechanism underlying EMDR

    Directory of Open Access Journals (Sweden)

    Zoe eSamara

    2011-03-01

    Full Text Available Series of horizontal saccadic eye movements (EMs are known to improve episodic memory retrieval in healthy adults and to facilitate the processing of traumatic memories in eye-movement desensitization and reprocessing (EMDR therapy. Several authors have proposed that EMs achieve these effects by increasing the functional connectivity of the two brain hemispheres, but direct evidence for this proposal is lacking. The aim of this study was to investigate whether memory enhancement following bilateral EMs is associated with increased interhemispheric coherence in the electroencephalogram (EEG. Fourteen healthy young adults were asked to freely recall lists of studied neutral and emotional words after a series of bilateral EMs and a control procedure. Baseline EEG activity was recorded before and after the EM and control procedures. Phase and amplitude coherence between bilaterally homologous brain areas were calculated for six frequency bands and electrode pairs across the entire scalp. Behavioral analyses showed that participants recalled more emotional (but not neutral words following the EM procedure than following the control procedure. However, the EEG analyses indicated no evidence that the EMs altered participants’ interhemispheric coherence or that improvements in recall were correlated with such changes in coherence. These findings cast doubt on the interhemispheric interaction hypothesis, and therefore may have important implications for future research on the neurobiological mechanism underlying EMDR.

  9. Models of logistic regression analysis, support vector machine, and back-propagation neural network based on serum tumor markers in colorectal cancer diagnosis.

    Science.gov (United States)

    Zhang, B; Liang, X L; Gao, H Y; Ye, L S; Wang, Y G

    2016-05-13

    We evaluated the application of three machine learning algorithms, including logistic regression, support vector machine and back-propagation neural network, for diagnosing congenital heart disease and colorectal cancer. By inspecting related serum tumor marker levels in colorectal cancer patients and healthy subjects, early diagnosis models for colorectal cancer were built using three machine learning algorithms to assess their corresponding diagnostic values. Except for serum alpha-fetoprotein, the levels of 11 other serum markers of patients in the colorectal cancer group were higher than those in the benign colorectal cancer group (P model and back-propagation, a neural network diagnosis model was built with diagnostic accuracies of 82 and 75%, sensitivities of 85 and 80%, and specificities of 80 and 70%, respectively. Colorectal cancer diagnosis models based on the three machine learning algorithms showed high diagnostic value and can help obtain evidence for the early diagnosis of colorectal cancer.

  10. RoboWeedSupport - Detection of weed locations in leaf occluded cereal crops using a fully convolutional neural network

    DEFF Research Database (Denmark)

    Dyrmann, Mads; Jørgensen, Rasmus Nyholm; Midtiby, Henrik Skov

    2017-01-01

    This pap er presents a metho d for au tomating weed detectio n in colour images despite heavy lea f occlusion. A fully convolu tio n al neural network is used to detect the weed s. The netwo rk is trained and validated on a tot al of more than 17,000 ann otations of w eeds in images from wint er w...

  11. Neural plasticity: the biological substrate for neurorehabilitation.

    Science.gov (United States)

    Warraich, Zuha; Kleim, Jeffrey A

    2010-12-01

    Decades of basic science have clearly demonstrated the capacity of the central nervous system (CNS) to structurally and functionally adapt in response to experience. The field of neurorehabilitation has begun to use this body of work to develop neurobiologically informed therapies that harness the key behavioral and neural signals that drive neural plasticity. The present review describes how neural plasticity supports both learning in the intact CNS and functional improvement in the damaged or diseased CNS. A pragmatic, interdisciplinary definition of neural plasticity is presented that may be used by both clinical and basic scientists studying neurorehabilitation. Furthermore, a description of how neural plasticity may act to drive different neural strategies underlying functional improvement after CNS injury or disease is provided. The understanding of the relationship between these different neural strategies, mechanisms of neural plasticity, and changes in behavior may facilitate the development of novel, more effective rehabilitation interventions. Copyright © 2010 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  12. Neural mechanisms of proactive and reactive cognitive control in social anxiety.

    Science.gov (United States)

    Schmid, Petra C; Kleiman, Tali; Amodio, David M

    2015-09-01

    Social anxiety--the fear of social embarrassment and negative evaluation by others--ranks among people's worst fears, and it is often thought to impair task performance. We investigated the neurocognitive processes through which trait social anxiety relates to task performance, proposing a model of the joint contributions of reactive control, theoretically associated with conflict monitoring and activity of the dorsal anterior cingulate cortex (dACC), and proactive control, theoretically associated with top-down regulation and activity of the dorsolateral prefrontal cortex (dlPFC). Participants varying in their degree of trait social anxiety completed the Eriksen flanker task while electroencephalography (EEG) was recorded. Task-related left dlPFC activity was indexed by relative left prefrontal EEG (inverse alpha), and conflict-related dACC activity was indexed by the N2r component of the event-related potential. Stronger activity in both regions predicted better response control, and greater social anxiety was associated with worse response control. Furthermore, for all participants, greater left prefrontal EEG activity predicted better behavioral control, but for high social anxiety participants only, greater N2r responses also predicted behavioral control. This pattern suggests that low social anxiety individuals engaged a proactive control process, driven by dlPFC activity, whereas high social anxiety individuals relied additionally on a reactive control process, driven by conflict-related dACC activity. These findings support a model of control that involves different patterns of interplay between proactive and reactive strategies and may help to explain self-regulatory impairments in social anxiety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Identification of neural firing patterns, frequency and temporal coding mechanisms in individual aortic baroreceptors

    Directory of Open Access Journals (Sweden)

    Huaguang eGu

    2015-08-01

    Full Text Available In rabbit depressor nerve fibers, an on-off firing pattern, period-1 firing, and integer multiple firing with quiescent state were observed as the static pressure level was increased. A bursting pattern with bursts at the systolic phase of blood pressure, continuous firing, and bursting with burst at diastolic phase and quiescent state at systolic phase were observed as the mean level of the dynamic blood pressure was increased. For both static and dynamic pressures, the firing frequency of the first two firing patterns increased and of the last firing pattern decreased due to the quiescent state. If the quiescent state is disregarded, the spike frequency becomes an increasing trend. The instantaneous spike frequency of the systolic phase bursting, continuous firing, and diastolic phase bursting can reflect the temporal process of the systolic phase, whole procedure, and diastolic phase of the dynamic blood pressure signal, respectively. With increasing the static current corresponding to pressure level, the deterministic Hodgkin-Huxley (HH model manifests a process from a resting state first to period-1 firing via a subcritical Hopf bifurcation and then to a resting state via a supercritical Hopf bifurcation, and the firing frequency increases. The on-off firing and integer multiple firing were here identified as noise-induced firing patterns near the subcritical and supercritical Hopf bifurcation points, respectively, using the stochastic HH model. The systolic phase bursting and diastolic phase bursting were identified as pressure-induced firings near the subcritical and supercritical Hopf bifurcation points, respectively, using an HH model with a dynamic signal. The firing, spike frequency, and instantaneous spike frequency observed in the experiment were simulated and explained using HH models. The results illustrate the dynamics of different firing patterns and the frequency and temporal coding mechanisms of aortic baroreceptor.

  14. Mechanisms of support of “green” projects financing: experience of countries

    Directory of Open Access Journals (Sweden)

    Ivan D. Rakov

    2017-06-01

    Full Text Available Objective to assess the effectiveness of the mechanisms supporting ldquogreenrdquo projectsrsquo funding in developed countries and in Russia. Methods comparative analysis regression analysis. Results the article substantiates the necessity of mainstreaming the environmental protection issues under modern conditions of the world economy development. It is emphasized that despite the advantages of the development of ldquogreenrdquo economy for society as a whole the market highlights a variety of hindering factors. In this context it is increasingly important to study the experience of countries in implementing projects on ldquogreenrdquo economy formation. We analyze the experience of Great Britain in creating special institutions to support ldquogreenrdquo investment raising funds mainly through the use of credit and warranty programs. The UK also demonstrates the experience of applying environmental taxes and a wide range of environmental financial products. Analysis of the experience of South Korea showed the country39s strategy for ldquogreenrdquo growth and the functioning of a framework law providing financial support to ldquogreenrdquo companies and private investment in this area. The experience of Canada province of Ontario shows that in the field of ldquogreenrdquo economy such support mechanisms are applied as ldquogreenrdquo bonds preferential tariff programs etc. Germany also demonstrates progress in addressing environmental problems by imposing requirements for the population in this area as well as the creation of preferential programs of financing ldquogreenrdquo projects. The analysis showed that in contrast to the studied countries in Russia there is no comprehensive mechanism of state support for environmental projects. The existing mechanisms are associated with the implementation of state programs in the sphere of hightech industries. Basing on regression analysis we estimated the influence of state support measures for

  15. A Novel Robot System Integrating Biological and Mechanical Intelligence Based on Dissociated Neural Network-Controlled Closed-Loop Environment.

    Directory of Open Access Journals (Sweden)

    Yongcheng Li

    Full Text Available We propose the architecture of a novel robot system merging biological and artificial intelligence based on a neural controller connected to an external agent. We initially built a framework that connected the dissociated neural network to a mobile robot system to implement a realistic vehicle. The mobile robot system characterized by a camera and two-wheeled robot was designed to execute the target-searching task. We modified a software architecture and developed a home-made stimulation generator to build a bi-directional connection between the biological and the artificial components via simple binomial coding/decoding schemes. In this paper, we utilized a specific hierarchical dissociated neural network for the first time as the neural controller. Based on our work, neural cultures were successfully employed to control an artificial agent resulting in high performance. Surprisingly, under the tetanus stimulus training, the robot performed better and better with the increasement of training cycle because of the short-term plasticity of neural network (a kind of reinforced learning. Comparing to the work previously reported, we adopted an effective experimental proposal (i.e. increasing the training cycle to make sure of the occurrence of the short-term plasticity, and preliminarily demonstrated that the improvement of the robot's performance could be caused independently by the plasticity development of dissociated neural network. This new framework may provide some possible solutions for the learning abilities of intelligent robots by the engineering application of the plasticity processing of neural networks, also for the development of theoretical inspiration for the next generation neuro-prostheses on the basis of the bi-directional exchange of information within the hierarchical neural networks.

  16. A Novel Robot System Integrating Biological and Mechanical Intelligence Based on Dissociated Neural Network-Controlled Closed-Loop Environment

    Science.gov (United States)

    Wang, Yuechao; Li, Hongyi; Zheng, Xiongfei

    2016-01-01

    We propose the architecture of a novel robot system merging biological and artificial intelligence based on a neural controller connected to an external agent. We initially built a framework that connected the dissociated neural network to a mobile robot system to implement a realistic vehicle. The mobile robot system characterized by a camera and two-wheeled robot was designed to execute the target-searching task. We modified a software architecture and developed a home-made stimulation generator to build a bi-directional connection between the biological and the artificial components via simple binomial coding/decoding schemes. In this paper, we utilized a specific hierarchical dissociated neural network for the first time as the neural controller. Based on our work, neural cultures were successfully employed to control an artificial agent resulting in high performance. Surprisingly, under the tetanus stimulus training, the robot performed better and better with the increasement of training cycle because of the short-term plasticity of neural network (a kind of reinforced learning). Comparing to the work previously reported, we adopted an effective experimental proposal (i.e. increasing the training cycle) to make sure of the occurrence of the short-term plasticity, and preliminarily demonstrated that the improvement of the robot’s performance could be caused independently by the plasticity development of dissociated neural network. This new framework may provide some possible solutions for the learning abilities of intelligent robots by the engineering application of the plasticity processing of neural networks, also for the development of theoretical inspiration for the next generation neuro-prostheses on the basis of the bi-directional exchange of information within the hierarchical neural networks. PMID:27806074

  17. Neural constraints and flexibility in language processing.

    Science.gov (United States)

    Huyck, Christian R

    2016-01-01

    Humans process language with their neurons. Memory in neurons is supported by neural firing and by short- and long-term synaptic weight change; the emergent behaviour of neurons, synchronous firing, and cell assembly dynamics is also a form of memory. As the language signal moves to later stages, it is processed with different mechanisms that are slower but more persistent.

  18. Clinical and microbiologic effects of chemical versus mechanical cleansing in professional supportive implant therapy

    NARCIS (Netherlands)

    Strooker, H; Rohn, S; Van Winkelhoff, AJ

    1998-01-01

    The aim of the present study was to compare the cleansing properties of mechanical supportive care for dental implants with the use of an etching gel. Sixteen patients underwent a 5-month clinical trial with monthly recalls. These patients, wearing maxillary complete dentures and mandibular

  19. Deterioration Mechanisms and Durability of Sprayed Concrete for Rock Support in Tunnels

    NARCIS (Netherlands)

    Hagelia, P.

    2011-01-01

    Steel fibre reinforced sprayed concretes used for rock support in tunnels are subjected to variable and complex exposure conditions. Structurally weakened concretes (5 to 35 years old) were investigated with respect to deterioration mechanisms, sources of aggressive agents and related engineering

  20. Policy-Relevant Systematic Reviews to Strengthen Health Systems: Models and Mechanisms to Support Their Production

    Science.gov (United States)

    Oliver, Sandra; Dickson, Kelly

    2016-01-01

    Support for producing systematic reviews about health systems is less well developed than for those about clinical practice. From interviewing policy makers and systematic reviewers we identified institutional mechanisms which bring systematic reviews and policy priorities closer by harnessing organisational and individual motivations, emphasising…

  1. Effects of Natural Sounds on Pain: A Randomized Controlled Trial with Patients Receiving Mechanical Ventilation Support.

    Science.gov (United States)

    Saadatmand, Vahid; Rejeh, Nahid; Heravi-Karimooi, Majideh; Tadrisi, Sayed Davood; Vaismoradi, Mojtaba; Jordan, Sue

    2015-08-01

    Nonpharmacologic pain management in patients receiving mechanical ventilation support in critical care units is under investigated. Natural sounds may help reduce the potentially harmful effects of anxiety and pain in hospitalized patients. The aim of this study was to examine the effect of pleasant, natural sounds on self-reported pain in patients receiving mechanical ventilation support, using a pragmatic parallel-arm, randomized controlled trial. The study was conducted in a general adult intensive care unit of a high-turnover teaching hospital, in Tehran, Iran. Between October 2011 and June 2012, we recruited 60 patients receiving mechanical ventilation support to the intervention (n = 30) and control arms (n = 30) of a pragmatic parallel-group, randomized controlled trial. Participants in both arms wore headphones for 90 minutes. Those in the intervention arm heard pleasant, natural sounds, whereas those in the control arm heard nothing. Outcome measures included the self-reported visual analog scale for pain at baseline; 30, 60, and 90 minutes into the intervention; and 30 minutes post-intervention. All patients approached agreed to participate. The trial arms were similar at baseline. Pain scores in the intervention arm fell and were significantly lower than in the control arm at each time point (p mechanical ventilation support. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  2. Protein kinase C substrate phosphorylation in relation to neural growth and synaptic plasticity: a common molecular mechanism underlying multiple neural functions

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.B.

    1987-01-01

    In these studies, we addressed the issues of: (1) whether neural protein kinase C (PKC) substrates might be altered in phosphorylation following induction of long-term potentiation (LTP); (2) whether PKC substrate phosphorylation might be specifically related to a model of neural plasticity other than LTP; and (3) whether the PKC substrates implicated in adult synaptic plasticity might be present in axonal growth cones given reports that high concentrations of PKC are found in these structures. Using quantitative analysis of multiple two-dimensional gels, we found that the two major substrates of exogenous purified PKC in adult hippocampal homogenate are both directly correlated to persistence of LTP. In rhesus monkey cerebral cortex, the proteins corresponding to protein F1 and 80k displayed topographical gradients in /sup 32/P-incorporation along the occipitotemporal visual processing pathway. The phosphorylation of both proteins was 11- and 14-fold higher, respectively, in temporal regions of this pathway implicated in the storage of visual representations, than in occipital regions, which do not appear to directly participate in visual memory functions.

  3. Mechanism change in a simulation of peer review: from junk support to elitism.

    Science.gov (United States)

    Paolucci, Mario; Grimaldo, Francisco

    2014-01-01

    Peer review works as the hinge of the scientific process, mediating between research and the awareness/acceptance of its results. While it might seem obvious that science would regulate itself scientifically, the consensus on peer review is eroding; a deeper understanding of its workings and potential alternatives is sorely needed. Employing a theoretical approach supported by agent-based simulation, we examined computational models of peer review, performing what we propose to call redesign , that is, the replication of simulations using different mechanisms . Here, we show that we are able to obtain the high sensitivity to rational cheating that is present in literature. In addition, we also show how this result appears to be fragile against small variations in mechanisms. Therefore, we argue that exploration of the parameter space is not enough if we want to support theoretical statements with simulation, and that exploration at the level of mechanisms is needed. These findings also support prudence in the application of simulation results based on single mechanisms, and endorse the use of complex agent platforms that encourage experimentation of diverse mechanisms.

  4. Age-related changes in the neural networks supporting semantic cognition: A meta-analysis of 47 functional neuroimaging studies.

    Science.gov (United States)

    Hoffman, Paul; Morcom, Alexa M

    2018-01-01

    Semantic cognition is central to understanding of language and the world and, unlike many cognitive domains, is thought to show little age-related decline. We investigated age-related differences in the neural basis of this critical cognitive domain by performing an activation likelihood estimation (ALE) meta-analysis of functional neuroimaging studies comparing young and older people. On average, young people outperformed their older counterparts during semantic tasks. Overall, both age groups activated similar left-lateralised regions. However, older adults displayed less activation than young people in some elements of the typical left-hemisphere semantic network, including inferior prefrontal, posterior temporal and inferior parietal cortex. They also showed greater activation in right frontal and parietal regions, particularly those held to be involved in domain-general controlled processing, and principally when they performed more poorly than the young. Thus, semantic processing in later life is associated with a shift from semantic-specific to domain-general neural resources, consistent with the theory of neural dedifferentiation, and a performance-related reduction in prefrontal lateralisation, which may reflect a response to increased task demands. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Impact of a Common Genetic Variation Associated With Putamen Volume on Neural Mechanisms of Attention-Deficit/Hyperactivity Disorder.

    Science.gov (United States)

    Xu, Bing; Jia, Tianye; Macare, Christine; Banaschewski, Tobias; Bokde, Arun L W; Bromberg, Uli; Büchel, Christian; Cattrell, Anna; Conrod, Patricia J; Flor, Herta; Frouin, Vincent; Gallinat, Jürgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Ittermann, Bernd; Martinot, Jean-Luc; Paillère Martinot, Marie-Laure; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Paus, Tomáš; Poustka, Luise; Smolka, Michael N; Walter, Henrik; Whelan, Robert; Schumann, Gunter; Desrivières, Sylvane

    2017-05-01

    In a recent genomewide association study of subcortical brain volumes, a common genetic variation at rs945270 was identified as having the strongest effect on putamen volume, a brain measurement linked to familial risk for attention-deficit/hyperactivity disorder (ADHD). To determine whether rs945270 might be a genetic determinant of ADHD, its effects on ADHD-related symptoms and neural mechanisms of ADHD, such as response inhibition and reward sensitivity, were explored. A large population sample of 1,834 14-year-old adolescents was used to test the effects of rs945270 on ADHD symptoms assessed through the Strengths and Difficulties Questionnaire and region-of-interest analyses of putamen activation by functional magnetic resonance imaging using the stop signal and monetary incentive delay tasks, assessing response inhibition and reward sensitivity, respectively. There was a significant link between rs945270 and ADHD symptom scores, with the C allele associated with lower symptom scores, most notably hyperactivity. In addition, there were sex-specific effects of this variant on the brain. In boys, the C allele was associated with lower putamen activity during successful response inhibition, a brain response that was not associated with ADHD symptoms. In girls, putamen activation during reward anticipation increased with the number of C alleles, most significantly in the right putamen. Remarkably, right putamen activation during reward anticipation tended to negatively correlate with ADHD symptoms. These results indicate that rs945270 might contribute to the genetic risk of ADHD partly through its effects on hyperactivity and reward processing in girls. Copyright © 2017 American Academy of Child and Adolescent Psychiatry. All rights reserved.

  6. The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

    Directory of Open Access Journals (Sweden)

    Wen Zhang

    Full Text Available BACKGROUND: The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs in the locking proximal humeral plate for treating proximal humerus fractures. METHODS: Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. RESULTS: Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001. When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P ≤ 0.0207. Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. CONCLUSIONS: Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

  7. Influences of social reward experience on behavioral responses to drugs of abuse: Review of shared and divergent neural plasticity mechanisms for sexual reward and drugs of abuse.

    Science.gov (United States)

    Beloate, Lauren N; Coolen, Lique M

    2017-12-01

    Different factors influence the development of drug addiction in humans, including social reward experiences. In animals, experience with social rewards, such as sexual behavior, pair bonding, social and environmental enrichment, can be protective. However, loss or lack of social rewards can lead to a vulnerability to drug-seeking behavior. The effects of social reward experience on drug-seeking behavior are associated with changes in the neural pathways that control drug-related behavior. This review will provide an introduction and overview of the mesolimbic pathway and the influence of social reward experience on drug-seeking behavior in rodents. Moreover, the research from our laboratory on effects of sexual experience and loss of sex reward on psychostimulant and opiate reward will be reviewed. Finally, we will review current knowledge of the neural mechanisms that underlie these interactions. Investigations of the neural underpinnings by which social and drug rewards interact contribute to improved understanding of the neural basis of vulnerability for drug addiction and reward-related behaviors in general. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Mechanical properties and supporting effect of CRLD bolts under static pull test conditions

    Science.gov (United States)

    Sun, Xiao-ming; Zhang, Yong; Wang, Dong; Yang, Jun; Xu, Hui-chen; He, Man-chao

    2017-01-01

    A device for supporting soft rock masses combined with a constant resistance structure characterized by constant resistance and large deformation at the end of a steel bar, known as the constant resistance and large deformation (CRLD) bolt, has recently been developed to counteract soft rock swelling that often occurs during deep mining. In order to further study the mechanical properties of the CRLD bolt, we investigated its mechanical properties by comparison with the conventional strength bolt (rebar) using static pull tests on many aspects, including supporting capacity, elongation, radial deformation, and energy absorption. The tests verified that the mechanical defects of the rebar, which include the decrease of bolt diameter, reduction of supporting capacity, and emergence and evolution of fracture until failure during the whole pull process, were caused by the Poisson's ratio effect. Due to the special structure set on the CRLD bolt, the bolt presents a seemingly unusual phenomenon of the negative Poisson's ratio effect, i.e., the diameter of the constant resistance structure increases while under-pulling. It is the very effect that ensures the extraordinary mechanical properties, including high resistance, large elongation, and strong energy absorption. According to the comparison and analysis of numerical simulation and field test, we can conclude that the CRLD bolt works better than the rebar bolt.

  9. Neural Mechanisms of Attention

    Science.gov (United States)

    1993-05-21

    attention deficit hyperactivity disorder ( ADHD ). These disorders may encompass a number of other cognitive deficits, but many theories focus on the...trial of methylphenidate in black adolescents. Attentional, behavioral, and physiological effects. CLINICAL.PEDIATRICS., 27,74-81. Bruto, V...Nakamura, K., Nishijo, H., & Fukuda, M. (1986). Hypothalamic neuron involvement in integration of reward , aversion, and cue signals. Journal of

  10. Neural bases of accented speech perception

    Directory of Open Access Journals (Sweden)

    Patti eAdank

    2015-10-01

    Full Text Available The recognition of unfamiliar regional and foreign accents represents a challenging task for the speech perception system (Adank, Evans, Stuart-Smith, & Scott, 2009; Floccia, Goslin, Girard, & Konopczynski, 2006. Despite the frequency with which we encounter such accents, the neural mechanisms supporting successful perception of accented speech are poorly understood. Nonetheless, candidate neural substrates involved in processing speech in challenging listening conditions, including accented speech, are beginning to be identified. This review will outline neural bases associated with perception of accented speech in the light of current models of speech perception, and compare these data to brain areas associated with processing other speech distortions. We will subsequently evaluate competing models of speech processing with regards to neural processing of accented speech. See Cristia et al. (2012 for an in-depth overview of behavioural aspects of accent processing.

  11. Neural bases of accented speech perception.

    Science.gov (United States)

    Adank, Patti; Nuttall, Helen E; Banks, Briony; Kennedy-Higgins, Daniel

    2015-01-01

    The recognition of unfamiliar regional and foreign accents represents a challenging task for the speech perception system (Floccia et al., 2006; Adank et al., 2009). Despite the frequency with which we encounter such accents, the neural mechanisms supporting successful perception of accented speech are poorly understood. Nonetheless, candidate neural substrates involved in processing speech in challenging listening conditions, including accented speech, are beginning to be identified. This review will outline neural bases associated with perception of accented speech in the light of current models of speech perception, and compare these data to brain areas associated with processing other speech distortions. We will subsequently evaluate competing models of speech processing with regards to neural processing of accented speech. See Cristia et al. (2012) for an in-depth overview of behavioral aspects of accent processing.

  12. Comparing interventions and exploring neural mechanisms of exercise in Parkinson disease: a study protocol for a randomized controlled trial.

    Science.gov (United States)

    Earhart, Gammon M; Duncan, Ryan P; Huang, John L; Perlmutter, Joel S; Pickett, Kristen A

    2015-02-05

    Effective treatment of locomotor dysfunction in Parkinson disease (PD) is essential, as gait difficulty is an early and major contributor to disability. Exercise is recommended as an adjunct to traditional treatments for improving gait, balance, and quality of life. Among the exercise approaches known to improve walking, tango and treadmill training have recently emerged as two promising therapies for improving gait, disease severity and quality of life, yet these two interventions have not been directly compared to each other. Prior studies have been helpful in identifying interventions effective in improving gait function, but have done little to elucidate the neural mechanisms underlying functional improvements. The primary objective of the proposed work is to compare the effects of three community-based exercise programs, tango, treadmill training and stretching, on locomotor function in individuals with PD. In addition, we aim to determine whether and how these interventions alter functional connectivity of locomotor control networks in the brain. One hundred and twenty right-handed individuals with idiopathic PD who are at least 30 years of age will be assigned in successive waves to one of three community-based exercise groups: tango dancing, treadmill training or stretching (control). Each group will receive three months of exercise training with twice weekly one-hour group classes. Each participant will be evaluated at three time points: pre-intervention (baseline), post-intervention (3 months), and follow-up (6 months). All evaluations will include assessment of gait, balance, disease severity, and quality of life. Baseline and post-intervention evaluations will also include task-based functional magnetic resonance imaging (fMRI) and resting state functional connectivity MRI. All MRI and behavioral measures will be conducted with participants OFF anti-Parkinson medication, with behavioral measures also assessed ON medication. This study will provide

  13. Heart Transplant and Mechanical Circulatory Support in Patients With Advanced Heart Failure.

    Science.gov (United States)

    Sánchez-Enrique, Cristina; Jorde, Ulrich P; González-Costello, José

    2017-05-01

    Patients with advanced heart failure have a poor prognosis and heart transplant is still the best treatment option. However, the scarcity of donors, long waiting times, and an increasing number of unstable patients have favored the development of mechanical circulatory support. This review summarizes the indications for heart transplant, candidate evaluation, current immunosuppression strategies, the evaluation and treatment of rejection, infectious prophylaxis, and short and long-term outcomes. Regarding mechanical circulatory support, we distinguish between short- and long-term support and the distinct strategies that can be used: bridge to decision, recovery, candidacy, transplant, and destination therapy. We then discuss indications, risk assessment, management of complications, especially with long-term support, and outcomes. Finally, we discuss future challenges and how the widespread use of long-term support for patients with advanced heart failure will only be viable if their complications and costs are reduced. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  14. STATEAID AS EFFECTIVE MECHANISM OF STATE REGULATION AND SUPPORT OF SMALL AND MEDIUM ENTREPRENEURSHIP

    Directory of Open Access Journals (Sweden)

    L. Kot

    2016-02-01

    Full Text Available In the article there is analysed the main approaches to the definition of state aid, including made by EU regulatory documents such as, for example, the Treaty Establishing the European Community and the Treaty on the Functioning of the European Union. Also there is considered the role and importance of the state aid in ensuring the effective functioning of mechanism of state regulation and support of small and medium enterprises. There is studied the experience of state support in the form of state aid to a number of European countries and legislative regulation of state aid in Ukraine.

  15. Mechanical Circulatory Support for the Failing Heart: Which Device to Choose

    Directory of Open Access Journals (Sweden)

    Mustafa Ahmed, MD

    2015-10-01

    Full Text Available Critical cardiogenic shock remains a problem with staggering mortality, with the best hope of survival depending on timely and aggressive intervention. This often requires the use of extracorporeal mechanical support in addition to vasoactive medications to manage patients through their initial insult. The decision to use such support must be made early in the clinical presentation, and is best done in a multidisciplinary fashion. In this article, we review the literature and provide an algorithm for the treatment of cardiogenic shock.

  16. Online estimation of respiratory mechanics in non-invasive pressure support ventilation: a bench model study.

    Science.gov (United States)

    Mulqueeny, Qestra; Tassaux, Didier; Vignaux, Laurence; Jolliet, Philippe; Schindhelm, Klaus; Redmond, Stephen; Lovell, Nigel H

    2010-01-01

    An online algorithm for determining respiratory mechanics in patients using non-invasive ventilation (NIV) in pressure support mode was developed and embedded in a ventilator system. Based on multiple linear regression (MLR) of respiratory data, the algorithm was tested on a patient bench model under conditions with and without leak and simulating a variety of mechanics. Bland-Altman analysis indicates reliable measures of compliance across the clinical range of interest (± 11-18% limits of agreement). Resistance measures showed large quantitative errors (30-50%), however, it was still possible to qualitatively distinguish between normal and obstructive resistances. This outcome provides clinically significant information for ventilator titration and patient management.

  17. Renewable energy support mechanisms in the Gulf Cooperation Council states: Analyzing the feasibility of feed-in tariffs and auction mechanisms

    NARCIS (Netherlands)

    Atalay, Yasemin; Kalfagianni, A.; Pattberg, Philipp

    2017-01-01

    Renewable energy will be a crucial ingredient in the transition to a more sustainable future. The renewable energy sector requires a variety of financial support mechanisms in order to further consolidate and expand. Currently, the most prominent renewable energy support mechanisms are feed-in

  18. [The mechanism of formation of the otoconia in the utricular supporting cells of the guinea pig].

    Science.gov (United States)

    Mori, N

    1997-02-01

    The mechanism of formation of the otocania in the utricular supporting cells of the guinea pig was investigated by means of an organ culture system using the potassium pyroantimonate (PA) precipitation method. The utricular otoconia and the secretory granules and mitochondria in the utricular supporting cells immediately after removal from the animal were positive to PA. When the specimens were treated with ethylene-glycol-0, 0-bis (2-aminoethyl)-N, N, N', N'-tetraacetic acid (EGTA) as a chelater prior to the PA staining, almost all deposits disappeared. This indicates that calcium is the main ion precipitated by the PA method. The utricules of the guinea pig were exposed to 30 mg of streptomycin sulfate per ml for 3 days in culture. The number of large lysosomes which contained vesicles and myeloid bodies in the supporting cells increased. On the other hand, the secretory granules were reduced in the cytoplasm of the supporting cells. Acid phosphatase activity in the lysosomes and the Golgi apparatus decreased. As a result of the PA treatment, these large lysosomes, especially the vesicles which were in them, contained a large quantity of calcium ion. From these findings, I conclude that the mechanism of formation of otoconia is as follows: The area of formation of otoconia is the supporting cells. Globular substances are the precursors of otoconia, and they contain calcium ion which was taken into the supporting cells. These globular substances are made in close relationship among the endplasmic reticula, secretory granules and lysosomes. They are secreted from the supporting cells and form the mature otoconia on the otoconial membrane.

  19. Preparedness planning before mechanical circulatory support: a "how-to" guide for palliative medicine clinicians.

    Science.gov (United States)

    Swetz, Keith M; Kamal, Arif H; Matlock, Daniel D; Dose, Ann Marie; Borkenhagen, Lynn S; Kimeu, Ashley K; Dunlay, Shannon M; Feely, Molly A

    2014-05-01

    The role of palliative medicine in the care of patients with advanced heart failure, including those who receive mechanical circulatory support, has grown dramatically in the last decade. Previous literature has suggested that palliative medicine providers are well poised to assist cardiologists, cardiothoracic surgeons, and the multidisciplinary cardiovascular team with promotion of informed consent and initial and iterative discussions regarding goals of care. Although preparedness planning has been described previously, the actual methods that can be used to complete a preparedness plan have not been well defined. Herein, we outline several key aspects of this approach and detail strategies for engaging patients who are receiving mechanical circulatory support in preparedness planning. Published by Elsevier Inc.

  20. Mechanical circulatory support in cardiogenic shock - what every interventional cardiologist should know.

    Science.gov (United States)

    Pyka, Lukasz; Pres, Damian; Przybylski, Roman; Pacholewicz, Jerzy; Poloński, Lech; Zembala, Marian; Gąsior, Mariusz

    2014-01-01

    Cardiogenic shock (CS) remains the main cause of death in patients with myocardial infarction. Conservative treatment alone does not sufficiently improve prognosis. Mortality in CS can only be significantly reduced with revascularization, both surgical and percutaneous. However some patients present with haemodynamic instability despite optimal medical treatment and complete revascularization, resulting in very high mortality rates. These patients require the implementation of mechanical circulatory support in order to increase systemic blood flow, protect against organ hypoperfusion and protect the myocardium through a decrease in oxygen consumption. In contemporary interventional cardiology it seems that every operator should be aware of all available mechanical circulatory support methods for their patients. This article aims to present the current state of knowledge and technical possibilities in this area.

  1. Evidence supporting extraocular muscle pulleys: refuting the platygean view of extraocular muscle mechanics.

    Science.gov (United States)

    Demer, Joseph L

    2006-01-01

    Late in the 20th century, it was recognized that connective tissue structures in the orbit influence the paths of the extraocular muscles and constitute their functional origins. Targeted investigations of these connective tissue "pulleys" led to the formulation of the active pulley hypothesis, which proposes that pulling directions of the rectus extraocular muscles are actively controlled via connective tissues. This review rebuts a series of criticisms of the active pulley hypothesis published by Jampel, and Jampel and Shi, in which these authors have disputed the existence and function of the pulleys. This article reviews published evidence for the existence of orbital pulleys, the active pulley hypothesis, and physiological tests of the active pulley hypothesis. Magnetic resonance imaging in a living subject and histological examination of a human cadaver directly illustrate the relationship of pulleys to extraocular muscles. Strong scientific evidence is cited that supports the existence of orbital pulleys and their role in ocular motility. The criticisms of the hypothesis have ignored mathematical truisms and strong scientific evidence. Actively control led orbital pulleys play a fundamental role in ocular motility. Pulleys profoundly influence the neural commands required to control eye movements and binocular alignment. Familiarity with the anatomy and physiology of the pulleys is requisite for a rational approach to diagnosing and treating strabismus using emerging methods. Conversely, approaches that deny or ignore the pulleys risk the sorts of errors that arise in geography and navigation from incorrect assumptions such as those of a flat ("platygean") earth.

  2. Controlling stress corrosion cracking in mechanism components of ground support equipment

    Science.gov (United States)

    Majid, W. A.

    1988-01-01

    The selection of materials for mechanism components used in ground support equipment so that failures resulting from stress corrosion cracking will be prevented is described. A general criteria to be used in designing for resistance to stress corrosion cracking is also provided. Stress corrosion can be defined as combined action of sustained tensile stress and corrosion to cause premature failure of materials. Various aluminum, steels, nickel, titanium and copper alloys, and tempers and corrosive environment are evaluated for stress corrosion cracking.

  3. New model for prediction binary mixture of antihistamine decongestant using artificial neural networks and least squares support vector machine by spectrophotometry method.

    Science.gov (United States)

    Mofavvaz, Shirin; Sohrabi, Mahmoud Reza; Nezamzadeh-Ejhieh, Alireza

    2017-07-05

    In the present study, artificial neural networks (ANNs) and least squares support vector machines (LS-SVM) as intelligent methods based on absorption spectra in the range of 230-300nm have been used for determination of antihistamine decongestant contents. In the first step, one type of network (feed-forward back-propagation) from the artificial neural network with two different training algorithms, Levenberg-Marquardt (LM) and gradient descent with momentum and adaptive learning rate back-propagation (GDX) algorithm, were employed and their performance was evaluated. The performance of the LM algorithm was better than the GDX algorithm. In the second one, the radial basis network was utilized and results compared with the previous network. In the last one, the other intelligent method named least squares support vector machine was proposed to construct the antihistamine decongestant prediction model and the results were compared with two of the aforementioned networks. The values of the statistical parameters mean square error (MSE), Regression coefficient (R2), correlation coefficient (r) and also mean recovery (%), relative standard deviation (RSD) used for selecting the best model between these methods. Moreover, the proposed methods were compared to the high- performance liquid chromatography (HPLC) as a reference method. One way analysis of variance (ANOVA) test at the 95% confidence level applied to the comparison results of suggested and reference methods that there were no significant differences between them. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. New model for prediction binary mixture of antihistamine decongestant using artificial neural networks and least squares support vector machine by spectrophotometry method

    Science.gov (United States)

    Mofavvaz, Shirin; Sohrabi, Mahmoud Reza; Nezamzadeh-Ejhieh, Alireza

    2017-07-01

    In the present study, artificial neural networks (ANNs) and least squares support vector machines (LS-SVM) as intelligent methods based on absorption spectra in the range of 230-300 nm have been used for determination of antihistamine decongestant contents. In the first step, one type of network (feed-forward back-propagation) from the artificial neural network with two different training algorithms, Levenberg-Marquardt (LM) and gradient descent with momentum and adaptive learning rate back-propagation (GDX) algorithm, were employed and their performance was evaluated. The performance of the LM algorithm was better than the GDX algorithm. In the second one, the radial basis network was utilized and results compared with the previous network. In the last one, the other intelligent method named least squares support vector machine was proposed to construct the antihistamine decongestant prediction model and the results were compared with two of the aforementioned networks. The values of the statistical parameters mean square error (MSE), Regression coefficient (R2), correlation coefficient (r) and also mean recovery (%), relative standard deviation (RSD) used for selecting the best model between these methods. Moreover, the proposed methods were compared to the high- performance liquid chromatography (HPLC) as a reference method. One way analysis of variance (ANOVA) test at the 95% confidence level applied to the comparison results of suggested and reference methods that there were no significant differences between them.

  5. Direct evidence for two different neural mechanisms for reading familiar and unfamiliar words: an intra-cerebral EEG study

    Directory of Open Access Journals (Sweden)

    Alexandra eJuphard

    2011-09-01

    Full Text Available After intensive practice, unfamiliar letter strings become familiar words and reading speed increases strikingly from a slow processing to a fast and with more global recognition of words. While this effect has been well documented at the behavioral level, its neural underpinnings are still unclear. The question is how the brain modulates the activity of the reading network according to the novelty of the items. Several models have proposed that familiar and unfamiliar words are not processed by separate networks but rather by common regions operating differently according to familiarity. This hypothesis has proved difficult to test at the neural level because the effects of familiarity and leng