WorldWideScience

Sample records for sustained input stimulus

  1. Input Deficit and Stimulus Enrichment: A Replication-with-Expansion

    Science.gov (United States)

    Friedrich, Douglas; And Others

    1973-01-01

    Two studies were conducted based on a methodological criticism of J. Gordon and H. Haywood's (1969) research on stimulus enrichment procedures with cultural-familial and brain-damaged retarded persons. (Author)

  2. Cross-modal stimulus conflict: the behavioral effects of stimulus input timing in a visual-auditory Stroop task.

    Science.gov (United States)

    Donohue, Sarah E; Appelbaum, Lawrence G; Park, Christina J; Roberts, Kenneth C; Woldorff, Marty G

    2013-01-01

    Cross-modal processing depends strongly on the compatibility between different sensory inputs, the relative timing of their arrival to brain processing components, and on how attention is allocated. In this behavioral study, we employed a cross-modal audio-visual Stroop task in which we manipulated the within-trial stimulus-onset-asynchronies (SOAs) of the stimulus-component inputs, the grouping of the SOAs (blocked vs. random), the attended modality (auditory or visual), and the congruency of the Stroop color-word stimuli (congruent, incongruent, neutral) to assess how these factors interact within a multisensory context. One main result was that visual distractors produced larger incongruency effects on auditory targets than vice versa. Moreover, as revealed by both overall shorter response times (RTs) and relative shifts in the psychometric incongruency-effect functions, visual-information processing was faster and produced stronger and longer-lasting incongruency effects than did auditory. When attending to either modality, stimulus incongruency from the other modality interacted with SOA, yielding larger effects when the irrelevant distractor occurred prior to the attended target, but no interaction with SOA grouping. Finally, relative to neutral-stimuli, and across the wide range of the SOAs employed, congruency led to substantially more behavioral facilitation than did incongruency to interference, in contrast to findings that within-modality stimulus-compatibility effects tend to be more evenly split between facilitation and interference. In sum, the present findings reveal several key characteristics of how we process the stimulus compatibility of cross-modal sensory inputs, reflecting stimulus processing patterns that are critical for successfully navigating our complex multisensory world.

  3. Cross-modal stimulus conflict: the behavioral effects of stimulus input timing in a visual-auditory Stroop task.

    Directory of Open Access Journals (Sweden)

    Sarah E Donohue

    Full Text Available Cross-modal processing depends strongly on the compatibility between different sensory inputs, the relative timing of their arrival to brain processing components, and on how attention is allocated. In this behavioral study, we employed a cross-modal audio-visual Stroop task in which we manipulated the within-trial stimulus-onset-asynchronies (SOAs of the stimulus-component inputs, the grouping of the SOAs (blocked vs. random, the attended modality (auditory or visual, and the congruency of the Stroop color-word stimuli (congruent, incongruent, neutral to assess how these factors interact within a multisensory context. One main result was that visual distractors produced larger incongruency effects on auditory targets than vice versa. Moreover, as revealed by both overall shorter response times (RTs and relative shifts in the psychometric incongruency-effect functions, visual-information processing was faster and produced stronger and longer-lasting incongruency effects than did auditory. When attending to either modality, stimulus incongruency from the other modality interacted with SOA, yielding larger effects when the irrelevant distractor occurred prior to the attended target, but no interaction with SOA grouping. Finally, relative to neutral-stimuli, and across the wide range of the SOAs employed, congruency led to substantially more behavioral facilitation than did incongruency to interference, in contrast to findings that within-modality stimulus-compatibility effects tend to be more evenly split between facilitation and interference. In sum, the present findings reveal several key characteristics of how we process the stimulus compatibility of cross-modal sensory inputs, reflecting stimulus processing patterns that are critical for successfully navigating our complex multisensory world.

  4. Limiting labor input is an overall prerequisite for sustainability

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen

    2006-01-01

    The purpose of the paper is to show by a simple, aggregate, descriptive model, how the importance of labor input to the production sector has to be revised in a future aiming at sustainable development. Despite substantial technological potentials for more eco-efficient utilization of nature...... process the production must comply with a stagnating or declining general consumption to avoid an endless build-up of surplus production. Consequently, it becomes essential to adjust labor input to the production sector accordingly. Temporary there are several outlets for a surplus production......, for instance giving it away to countries more in need, but in the longer term the only solution is to limit the labor input to production, which is here meant as labor’s total contribution to production. This input can be split up into following factors: 1) Population, 2) Labor force fraction, 3) Working time...

  5. Simultaneous external and internal stabilization of linear systems with input saturation and non-input-additive sustained disturbances

    NARCIS (Netherlands)

    Wang, Xu; Saberi, Ali; Grip, H°avard Fjær; Stoorvogel, Antonie Arij

    2012-01-01

    In this paper, we study simultaneous external and internal stabilization of the linear system under input saturation and non-input additive sustained disturbances. For systems that are asymptotic null controllable with bounded control, it is shown that a nonlinear dynamic feedback controller can be

  6. Sensitivity to Interaural Time Differences Conveyed in the Stimulus Envelope: Estimating Inputs of Binaural Neurons Through the Temporal Analysis of Spike Trains.

    Science.gov (United States)

    Dietz, Mathias; Wang, Le; Greenberg, David; McAlpine, David

    2016-08-01

    Sound-source localization in the horizontal plane relies on detecting small differences in the timing and level of the sound at the two ears, including differences in the timing of the modulated envelopes of high-frequency sounds (envelope interaural time differences (ITDs)). We investigated responses of single neurons in the inferior colliculus (IC) to a wide range of envelope ITDs and stimulus envelope shapes. By a novel means of visualizing neural activity relative to different portions of the periodic stimulus envelope at each ear, we demonstrate the role of neuron-specific excitatory and inhibitory inputs in creating ITD sensitivity (or the lack of it) depending on the specific shape of the stimulus envelope. The underlying binaural brain circuitry and synaptic parameters were modeled individually for each neuron to account for neuron-specific activity patterns. The model explains the effects of envelope shapes on sensitivity to envelope ITDs observed in both normal-hearing listeners and in neural data, and has consequences for understanding how ITD information in stimulus envelopes might be maximized in users of bilateral cochlear implants-for whom ITDs conveyed in the stimulus envelope are the only ITD cues available.

  7. AGRICULTURAL PRODUCTIVITY AND SUSTAINABILITY: EVIDENCE FROM LOW INPUT FARMING IN ARGENTINA

    OpenAIRE

    de Prada, Jorge D.; Bravo-Ureta, Boris E.; Shah, Farhed A.

    2003-01-01

    The tradeoff between short-term agricultural productivity and sustainability is examined with a statistical analysis of evidence from low input agriculture in Argentina. Estimation results show that more intensive land use, corporate leasing of land, and larger farm size are likely to increase current revenues, but at the cost of sustainability.

  8. Overexpectation: Response Loss during Sustained Stimulus Compounding in the Rabbit Nictitating Membrane Preparation

    Science.gov (United States)

    Kehoe, E. James; White, Natasha E.

    2004-01-01

    Rabbits were given reinforced training of the nictitating membrane (NM) response using separate conditioned stimuli (CSs), which were a tone, light, and/or tactile vibration. Then, two CSs were compounded and given further pairings with the unconditioned stimulus (US). Evidence of both overexpectation and summation effects appeared. That is,…

  9. Role of input self-sufficiency in the economic and environmental sustainability of specialised dairy farms.

    Science.gov (United States)

    Lebacq, T; Baret, P V; Stilmant, D

    2015-03-01

    Increasing input self-sufficiency is often viewed as a target to improve sustainability of dairy farms. However, few studies have specifically analysed input self-sufficiency, by including several technical inputs and without only focussing on animal feeding, in order to explore its impact on farm sustainability. To address this gap, our work has three objectives as follows: (1) identifying the structural characteristics required by specialised dairy farms located in the grassland area to be self-sufficient; (2) analysing the relationships between input self-sufficiency, environmental and economic sustainability; and (3) studying how the farms react to a decrease in milk price according to their self-sufficiency degree. Based on farm accounting databases, we categorised 335 Walloon specialised conventional dairy farms into four classes according to their level of input self-sufficiency. To this end, we used as proxy the indicator of economic autonomy - that is, the ratio between costs of inputs related to animal production, crop production and energy use and the total gross product. Classes were then compared using multiple comparison tests and canonical discriminant analysis. A total of 30 organic farms - among which 63% had a high level of economic autonomy - were considered separately and compared with the most autonomous class. We showed that a high degree of economic autonomy is associated, in conventional farms, with a high proportion of permanent grassland in the agricultural area. The most autonomous farms used less input - especially animal feeding - for a same output level, and therefore combined good environmental and economic performances. Our results also underlined that, in a situation of decrease in milk price, the least autonomous farms had more latitude to decrease their input-related costs without decreasing milk production. Their incomes per work unit were, therefore, less impacted by falling prices, but remained lower than those of more

  10. Integration: valuing stakeholder input in setting priorities for socially sustainable egg production.

    Science.gov (United States)

    Swanson, J C; Lee, Y; Thompson, P B; Bawden, R; Mench, J A

    2011-09-01

    Setting directions and goals for animal production systems requires the integration of information achieved through internal and external processes. The importance of stakeholder input in setting goals for sustainable animal production systems should not be overlooked by the agricultural animal industries. Stakeholders play an integral role in setting the course for many aspects of animal production, from influencing consumer preferences to setting public policy. The Socially Sustainable Egg Production Project (SSEP) involved the development of white papers on various aspects of egg production, followed by a stakeholder workshop to help frame the issues for the future of sustainable egg production. Representatives from the environmental, food safety, food retail, consumer, animal welfare, and the general farm and egg production sectors participated with members of the SSEP coordination team in a 1.5-d workshop to explore socially sustainable egg production. This paper reviews the published literature on values integration methodologies and the lessons learned from animal welfare assessment models. The integration method used for the SSEP stakeholder workshop and its outcome are then summarized. The method used for the SSEP stakeholder workshop can be used to obtain stakeholder input on sustainable production in other farm animal industries.

  11. A graph-theoretical analysis algorithm for quantifying the transition from sensory input to motor output by an emotional stimulus.

    Science.gov (United States)

    Karmonik, Christof; Fung, Steve H; Dulay, M; Verma, A; Grossman, Robert G

    2013-01-01

    Graph-theoretical analysis algorithms have been used for identifying subnetworks in the human brain during the Default Mode State. Here, these methods are expanded to determine the interaction of the sensory and the motor subnetworks during the performance of an approach-avoidance paradigm utilizing the correlation strength between the signal intensity time courses as measure of synchrony. From functional magnetic resonance imaging (fMRI) data of 9 healthy volunteers, two signal time courses, one from the primary visual cortex (sensory input) and one from the motor cortex (motor output) were identified and a correlation difference map was calculated. Graph networks were created from this map and visualized with spring-embedded layouts and 3D layouts in the original anatomical space. Functional clusters in these networks were identified with the MCODE clustering algorithm. Interactions between the sensory sub-network and the motor sub-network were quantified through the interaction strengths of these clusters. The percentages of interactions involving the visual cortex ranged from 85 % to 18 % and the motor cortex ranged from 40 % to 9 %. Other regions with high interactions were: frontal cortex (19 ± 18 %), insula (17 ± 22 %), cuneus (16 ± 15 %), supplementary motor area (SMA, 11 ± 18 %) and subcortical regions (11 ± 10 %). Interactions between motor cortex, SMA and visual cortex accounted for 12 %, between visual cortex and cuneus for 8 % and between motor cortex, SMA and cuneus for 6 % of all interactions. These quantitative findings are supported by the visual impressions from the 2D and 3D network layouts.

  12. Matrix sustainability : applying input-output analysis to environmental and economic sustainability indicators : case: Finnish Forest Sector

    OpenAIRE

    Paloviita, Ari

    2004-01-01

    Pre-requisite for all sustainability actions in business is accurate measurement of economic, environmental and social performance. Sustainability indicators, or indicator sets, are then the tools, which simplify the complex sustainability information applicable for management processes, decision-making and communication. Measuring business sustainability is not an easy task, especially while simultaneously considering macro-level sustainability. Indicators should somehow capture the corporat...

  13. Development of a Low Input and sustainable Switchgrass Feedstock Production System Utilizing Beneficial Bacterial Endophytes

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Chuansheng [IALR; Nowak, Jerzy [VPISU; Seiler, John [VPISU

    2014-10-24

    Switchgrass represents a promising feedstock crop for US energy sustainability. However, its broad utilization for bioenergy requires improvements of biomass yields and stress tolerance. In this DOE funded project, we have been working on harnessing beneficial bacterial endophytes to enhance switchgrass performance and to develop a low input feedstock production system for marginal lands that do not compete with the production of food crops. We have demonstrated that one of most promising plant growth-promoting bacterial endophytes, Burkholderia phytofirmans strain PsJN, is able to colonize roots and significantly promote growth of switchgrass cv. Alamo under in vitro, growth chamber, greenhouse, as well as field conditions. Furthermore, PsJN bacterization improved growth and development of switchgrass seedlings, significantly stimulated plant root and shoot growth, and tiller number in the field, and enhanced biomass accumulation on both poor (p<0.001) and rich (p<0.05) soils, with more effective stimulation of plant growth in low fertility soil. Plant physiology measurements showed that PsJN inoculated Alamo had consistently lower transpiration, lower stomatal conductance, and higher water use efficiency in greenhouse conditions. These physiological changes may significantly contribute to the recorded growth enhancement. PsJN inoculation rapidly results in an increase in photosynthetic rates which contributes to the advanced growth and development. Some evidence suggests that this initial growth advantage decreases with time when resources are not limited such as in greenhouse studies. Additionally, better drought resistance and drought hardening were observed in PsJN inoculated switchgrass. Using the DOE-funded switchgrass EST microarray, in a collaboration with the Genomics Core Facility at the Noble Foundation, we have determined gene expression profile changes in both responsive switchgrass cv. Alamo and non-responsive cv. Cave-in-Rock (CR) following Ps

  14. Globalization of pesticide technology and meeting the needs of low-input sustainable agriculture

    NARCIS (Netherlands)

    den Hond, F.; Groenewegen, P.; Vorley, W. T.

    1999-01-01

    The focus of this paper is the challenge to technology development in the international pesticide industry. We address these challenges within the context of debates on how to achieve an environmentally and economically sustainable world food production system. Forces acting within and upon both

  15. Monitoring the inputs required to extend and sustain hygiene promotion: findings from the GLAAS 2013/2014 survey.

    Science.gov (United States)

    Moreland, Leslie D; Gore, Fiona M; Andre, Nathalie; Cairncross, Sandy; Ensink, Jeroen H J

    2016-08-01

    There are significant gaps in information about the inputs required to effectively extend and sustain hygiene promotion activities to improve people's health outcomes through water, sanitation and hygiene (WASH) interventions. We sought to analyse current country and global trends in the use of key inputs required for effective and sustainable implementation of hygiene promotion to help guide hygiene promotion policy and decision-making after 2015. Data collected in response to the GLAAS 2013/2014 survey from 93 countries of 94 were included, and responses were analysed for 12 questions assessing the inputs and enabling environment for hygiene promotion under four thematic areas. Data were included and analysed from 20 External Support Agencies (ESA) of 23 collected through self-administered surveys. Firstly, the data showed a large variation in the way in which hygiene promotion is defined and what constitutes key activities in this area. Secondly, challenges to implement hygiene promotion are considerable: include poor implementation of policies and plans, weak coordination mechanisms, human resource limitations and a lack of available hygiene promotion budget data. Despite the proven benefits of hand washing with soap, a critical hygiene-related factor in minimising infection, GLAAS 2013/2014 survey data showed that hygiene promotion remains a neglected component of WASH. Additional research to identify the context-specific strategies and inputs required to enhance the effectiveness of hygiene promotion at scale are needed. Improved data collection methods are also necessary to advance the availability and reliability of hygiene-specific information. © 2016 John Wiley & Sons Ltd.

  16. Assessing sustainability of a low-input single-farm vegetable box-scheme using emergy and LCA methodology

    DEFF Research Database (Denmark)

    Markussen, Mads Ville; Kulak, M.; Østergård, Hanne

    2012-01-01

    and successfully worked on reducing external inputs. The system provides over 70 varieties of seasonal vegetables as well as biodiversity conservation and other ecosystem services. As a main goal of the study was to locate opportunities for sustainability improvements for the food production, we chose the yearly...... as well as the comparison between LCA and emergy analysis will be presented at the conference. In conclusion, from a biophysical perspective, agricultural systems’ primary societal function is to convert local renewable flows of sun, rain and wind into food, fodder and fiber by investing a minimum...

  17. Sustainable agricultural practices: energy inputs and outputs, pesticide, fertilizer and greenhouse gas management.

    Science.gov (United States)

    Wang, Yue-Wen

    2009-01-01

    The food security issue was addressed by the development of "modern agriculture" in the last century. But food safety issues and environment degradation were the consequences suffered as a result. Climate change has been recognized as the result of release of stored energy in fossil fuel into the atmosphere. Homogeneous crop varieties, machinery, pesticides and fertilizers are the foundation of uniform commodities in modern agriculture. Fossil fuels are used to manufacture fertilizers and pesticides as well as the energy source for agricultural machinery, thus characterizes modern agriculture. Bio-fuel production and the possibility of the agriculture system as a form of energy input are discussed.

  18. Retinal light input is required to sustain plasma melatonin rhythms in Nile tilapia Oreochromis niloticus niloticus.

    Science.gov (United States)

    Martinez-Chavez, C C; Migaud, H

    2009-05-07

    The aim of this work was to confirm previous findings suggesting that the eyes are required for night-time melatonin production in Nile tilapia and further characterise this divergent circadian organisation. To do so, melatonin levels were firstly measured in eyecups and plasma to determine circadian patterns of melatonin production. Secondly, the effect of partial ophthalmectomy on the suppression of melatonin production was determined in vivo as well as ex vivo pineal light/dark sensitivity. Finally, to investigate whether such findings could be related to post-surgery stress, melatonin analyses were performed in the subsequent 24 h and 7 days post-ophthalmectomy with cortisol levels assessed as an indicator of stress. Our results showed an inverse pattern of melatonin production in the eye cups of tilapia compared to blood circulating levels, suggesting different roles played by melatonin in these two tissues. Results then demonstrated that total or partial ophthalmectomy resulted in the suppression of night-time melatonin production. Furthermore, although pineals in culture were shown to be photosensitive, night-time melatonin levels were much lower than seen in other species. Finally, when performing sampling immediately or one week post-surgery, no difference in the melatonin profiles were observed. It is therefore unlikely that post-surgery stress would explain such suppression in melatonin production although all fish displayed high cortisol levels most probably due to social and handling stress. Taken together, these results provide further evidence of a new type of circadian organisation in a teleost species where the eyes are required to sustain night-time melatonin levels.

  19. Assessing sustainability of low-external-input farm management systems with the nutrient monitoring approach: a case study in Kenya

    NARCIS (Netherlands)

    Jager, de A.; Onduru, D.; Wijk, van M.S.; Vlaming, J.; Gachini, G.N.

    2001-01-01

    In the search for Integrated Nutrient Management practices in response to the widely observed soil fertility decline in Sub-Saharan Africa, the potential of low-external-input and organic farming remains to be systematically examined. The nutrient monitoring concept was used to assess the impact of

  20. Annual variation in weather: its implications for sustainability in the case of optimising nitrogen input in sugar beet

    NARCIS (Netherlands)

    Koeijer, de T.J.; Buck, de A.J.; Wossink, G.A.A.; Oenema, J.; Renkema, J.A.; Struik, P.C.

    2003-01-01

    Efficient crop husbandry is crucial in order to prevent unnecessary emissions of environmentally damaging inputs and to maintain economic soundness, but it raises the question of which productivity and efficiency levels should be realised. Agronomists and economists are still debating this issue, as

  1. Evaluating the Sustainability of a Small-Scale Low-Input Organic Vegetable Supply System in the United Kingdom

    DEFF Research Database (Denmark)

    Markussen, Mads Ville; Kulak, Michal; Smith, Laurence G.

    2014-01-01

    Resource use and environmental impacts of a small-scale low-input organic vegetable supply system in the United Kingdom were assessed by emergy accounting and Life Cycle Assessment (LCA). The system consisted of a farm with high crop diversity and a related box-scheme distribution system. We...... embedded in an industrial economy, about 90% of resources (seJ) were used for supporting labor and service....

  2. Energy inputs and outputs and sustainability of corn silage production; Balanco energetico e sutentabilidade na producao de silagem de milho

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Alessandro Torres; Daga, Jacir [Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil). Grupo de Pesquisas em Ambiencia do Oeste do Parana], e-mail: atcampos3@yahoo.com.br; Zanini, Agostinho; Prestes, Tania Maria Vicentini; Dalmolin, Maria Fatima da Silva [Centro Federal de Educacao Tecnologica do Parana (CEFET-PR), Medianeira, PR (Brazil); Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil). Centro de Ciencias Agrarias; Campos, Aloisio Torres de [EMBRAPA Gado de Leite, Juiz de Fora, MG (Brazil); Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil). Grupo de Pesquisas em Ambiencia do Oeste do Parana

    2004-07-01

    The agricultural ecosystem as way of converting solar energy in products, needs several energy sources, among that sources stand out fertilizers, agricultural defensives and others. These inputs are derived from fossils. In the present paper, it was studied the energy flows involved in corn silage production in a no tillage crop system, in Sao Miguel of Iguacu-Parana State/Brazil. In the direct energy flow, the fuels and lubricants were the largest consumers, representing 45.90% of the total, the agricultural defensives were responsible for the consumption of 24.12% of the total, while the fertilizers for 10.53% of the total consumption. By computing the fossil origin components, fuels, lubricants, defensive and fertilizers, the participation of the total consumption of energy was of 84.07%. (author)

  3. Evaluating the Sustainability of a Small-Scale Low-Input Organic Vegetable Supply System in the United Kingdom

    Directory of Open Access Journals (Sweden)

    Mads V. Markussen

    2014-04-01

    Full Text Available Resource use and environmental impacts of a small-scale low-input organic vegetable supply system in the United Kingdom were assessed by emergy accounting and Life Cycle Assessment (LCA. The system consisted of a farm with high crop diversity and a related box-scheme distribution system. We compared empirical data from this case system with two modeled organic food supply systems representing high- and low-yielding practices for organic vegetable production. Further, these systems were embedded in a supermarket distribution system and they provided the same amount of comparable vegetables at the consumers’ door as the case system. The on-farm resource use measured in solar equivalent Joules (seJ was similar for the case system and the high-yielding model system and higher for the low-yielding model system. The distribution phase of the case system was at least three times as resource efficient as the models and had substantially less environmental impacts when assessed using LCA. The three systems ranked differently for emissions with the high-yielding model system being the worst for terrestrial ecotoxicity and the case system the worst for global warming potential. As a consequence of being embedded in an industrial economy, about 90% of resources (seJ were used for supporting labor and service.

  4. Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Controls Stimulus-Transcription Coupling in the Hypothalamic-Pituitary-Adrenal Axis to Mediate Sustained Hormone Secretion During Stress

    Science.gov (United States)

    Stroth, Nikolas; Liu, Ying; Aguilera, Greti; Eiden, Lee E.

    2011-01-01

    External and internal stimuli that threaten homeostasis trigger coordinated stress responses through activation of specialised neuroendocrine circuits. In mammals, the hypothalamic-pituitary-adrenal (HPA) axis mediates responses to stressors such as restraint, ultimately enhancing adrenocortical hormone secretion. Pituitary adenylate cyclase-activating polypeptide (PACAP) has been implicated in central control of the HPA axis, and we have recently shown PACAP-dependent expression of corticotropin-releasing hormone (CRH) and secretion of corticosterone in response to restraint. We now provide a more detailed analysis of PACAP-dependent HPA axis stimulation in the mouse, indicating that the hypothalamic paraventricular nucleus (PVN) is the primary site of action. We demonstrate by quantitative PCR and in situ hybridisation that upregulation of mRNAs encoding CRH and inducible transcription factors from the Nr4a family (Nur77, Nor1) in the PVN is PACAP-dependent. Furthermore, CRH hnRNA is rapidly upregulated in cultured hypothalamic neurones after treatment with PACAP. Induction of Nr4a factors (Nur77, Nurr1) in response to restraint is attenuated in the pituitary gland of PACAP-deficient mice. In the adrenal glands, restraint elicits a marked PACAP-dependent increase in adrenocortical mRNA levels of all three Nr4a transcription factors, SF-1 (steroidogenic factor 1; Nr5a1), steroidogenic acute regulatory protein (StAR) and steroid 21-hydroxylase. Taken together, our results show that PACAP controls HPA responses to restraint primarily at the level of the hypothalamus by upregulating CRH, possibly involving transcription factors such as Nur77 and Nor1. Subsequent adrenocortical steroidogenesis also appears to involve PACAP-dependent stimulus-transcription coupling, suggesting a mechanism by which PACAP exerts control over HPA axis function during stress. PMID:21824204

  5. Dopamine modulation of GABAergic function enables network stability and input selectivity for sustaining working memory in a computational model of the prefrontal cortex.

    Science.gov (United States)

    Lew, Sergio E; Tseng, Kuei Y

    2014-12-01

    Dopamine modulation of GABAergic transmission in the prefrontal cortex (PFC) is thought to be critical for sustaining cognitive processes such as working memory and decision-making. Here, we developed a neurocomputational model of the PFC that includes physiological features of the facilitatory action of dopamine on fast-spiking interneurons to assess how a GABAergic dysregulation impacts on the prefrontal network stability and working memory. We found that a particular non-linear relationship between dopamine transmission and GABA function is required to enable input selectivity in the PFC for the formation and retention of working memory. Either degradation of the dopamine signal or the GABAergic function is sufficient to elicit hyperexcitability in pyramidal neurons and working memory impairments. The simulations also revealed an inverted U-shape relationship between working memory and dopamine, a function that is maintained even at high levels of GABA degradation. In fact, the working memory deficits resulting from reduced GABAergic transmission can be rescued by increasing dopamine tone and vice versa. We also examined the role of this dopamine-GABA interaction for the termination of working memory and found that the extent of GABAergic excitation needed to reset the PFC network begins to occur when the activity of fast-spiking interneurons surpasses 40 Hz. Together, these results indicate that the capability of the PFC to sustain working memory and network stability depends on a robust interplay of compensatory mechanisms between dopamine tone and the activity of local GABAergic interneurons.

  6. Carbon cycling of Lake Kivu (East Africa: net autotrophy in the epilimnion and emission of CO2 to the atmosphere sustained by geogenic inputs.

    Directory of Open Access Journals (Sweden)

    Alberto V Borges

    Full Text Available We report organic and inorganic carbon distributions and fluxes in a large (>2000 km2 oligotrophic, tropical lake (Lake Kivu, East Africa, acquired during four field surveys, that captured the seasonal variations (March 2007-mid rainy season, September 2007-late dry season, June 2008-early dry season, and April 2009-late rainy season. The partial pressure of CO2 (pCO2 in surface waters of the main basin of Lake Kivu showed modest spatial (coefficient of variation between 3% and 6%, and seasonal variations with an amplitude of 163 ppm (between 579±23 ppm on average in March 2007 and 742±28 ppm on average in September 2007. The most prominent spatial feature of the pCO2 distribution was the very high pCO2 values in Kabuno Bay (a small sub-basin with little connection to the main lake ranging between 11,213 ppm and 14,213 ppm (between 18 and 26 times higher than in the main basin. Surface waters of the main basin of Lake Kivu were a net source of CO2 to the atmosphere at an average rate of 10.8 mmol m(-2 d(-1, which is lower than the global average reported for freshwater, saline, and volcanic lakes. In Kabuno Bay, the CO2 emission to the atmosphere was on average 500.7 mmol m(-2 d(-1 (∼46 times higher than in the main basin. Based on whole-lake mass balance of dissolved inorganic carbon (DIC bulk concentrations and of its stable carbon isotope composition, we show that the epilimnion of Lake Kivu was net autotrophic. This is due to the modest river inputs of organic carbon owing to the small ratio of catchment area to lake surface area (2.15. The carbon budget implies that the CO2 emission to the atmosphere must be sustained by DIC inputs of geogenic origin from deep geothermal springs.

  7. Stimulus Responsive Nanoparticles

    Science.gov (United States)

    Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2017-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment including a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  8. Carbon cycling in the epilimnion of Lake Kivu (East Africa): surface net autotrophy and emission of CO2 to the atmosphere sustained by geogenic inputs

    Science.gov (United States)

    Borges, Alberto V.; Bouillon, Steven; Morana, Cédric D. T.; Servais, Pierre; Descy, Jean-Pierre; Darchambeau, François

    2013-04-01

    Lake Kivu [2.50°S 1.59°S 29.37°E 28.83°E] is one of the East African great lakes (2370 km2 surface area, 550 km3 volume). It is a deep (maximum depth of 485 m) meromictic lake, with an oxic mixolimnion down to 70 m maximum, and a deep monolimnion rich in dissolved gases and nutrients. Lake Kivu is permanently stratified (meromictic) and deep layers receive heat, salts, and CO2 from deep geothermal springs. Seasonality of the physical and chemical vertical structure and biological activity in surface waters of Lake Kivu is driven by the oscillation between the dry season (June-September) and the rainy season (October-May), the former characterized by a deepening of the mixolimnion. This seasonal mixing favours the input of dissolved nutrients and the development of diatoms, while, during the rest of the year, the phytoplankton assemblage is dominated by cyanobacteria, chrysophytes and cryptophytes. Huge amounts of CO2 and methane (CH4) (300 km3 and 60 km3, respectively, at 0°C and 1 atm] are dissolved in the deep layers of Lake Kivu. The CO2 is mainly geogenic. Large scale industrial extraction of CH4 from the deep layers of Lake Kivu is planned which could affect the ecology and biogeochemical cycling of C of the lake and change for instance the emission of greenhouse gases such as CH4 and CO2. Here, we report a data set covering the seasonality of CO2 dynamics and fluxes, in conjunction with mass balances of C, and process rate measurements (primary production and bacterial production). In order to capture the seasonal variations of the studied quantities, four cruises were carried out in Lake Kivu on 15/03-29/03/2007 (mid rainy season), 28/08-10/09/2007 (late dry season), 21/06-03/07/2008 (early dry season) and 21/04-05/05/2009 (late rainy season). We show that the lake is a modest source of CO2 to the atmosphere but which is sustained by geogenic inputs from depth rather than net heterotrophy as reported in lakes in general. Indeed we provide several lines

  9. Measuring the environmental sustainability performance of global supply chains: A multi-regional input-output analysis for carbon, sulphur oxide and water footprints.

    Science.gov (United States)

    Acquaye, Adolf; Feng, Kuishuang; Oppon, Eunice; Salhi, Said; Ibn-Mohammed, Taofeeq; Genovese, Andrea; Hubacek, Klaus

    2017-02-01

    Measuring the performance of environmentally sustainable supply chains instead of chain constitute has become a challenge despite the convergence of the underlining principles of sustainable supply chain management. This challenge is exacerbated by the fact that supply chains are inherently dynamic and complex and also because multiple measures can be used to characterize performances. By identifying some of the critical issues in the literature regarding performance measurements, this paper contributes to the existing body of literature by adopting an environmental performance measurement approach for economic sectors. It uses economic sectors and evaluates them on a sectoral level in specific countries as well as part of the Global Value Chain based on the established multi-regional input-output (MRIO) modeling framework. The MRIO model has been used to calculate direct and indirect (that is supply chain or upstream) environmental effects such as CO2, SO2, biodiversity, water consumption and pollution to name just a few of the applications. In this paper we use MRIO analysis to calculate emissions and resource consumption intensities and footprints, direct and indirect impacts, and net emission flows between countries. These are exemplified by using carbon emissions, sulphur oxide emissions and water use in two highly polluting industries; Electricity production and Chemical industry in 33 countries, including the EU-27, Brazil, India and China, the USA, Canada and Japan from 1995 to 2009. Some of the highlights include: On average, direct carbon emissions in the electricity sector across all 27 member states of the EU was estimated to be 1368 million tons and indirect carbon emissions to be 470.7 million tons per year representing 25.6% of the EU-27 total carbon emissions related to this sector. It was also observed that from 2004, sulphur oxide emissions intensities in electricity production in India and China have remained relatively constant at about 62.8 g

  10. Stimulus Variables and Interpersonal Attraction: The Stimulus Context.

    Science.gov (United States)

    Griffitt, William

    In interpersonal attraction, studies and judgment research evaluation of a stimulus is often a function of the context within which the stimulus appears. The first experiment was designed to examine "contrast effects" (shifts in the rated value of a stimulus away from the contextual values) when all attitudinal information was received from two…

  11. Coding stimulus amplitude by correlated neural activity.

    Science.gov (United States)

    Metzen, Michael G; Ávila-Åkerberg, Oscar; Chacron, Maurice J

    2015-04-01

    While correlated activity is observed ubiquitously in the brain, its role in neural coding has remained controversial. Recent experimental results have demonstrated that correlated but not single-neuron activity can encode the detailed time course of the instantaneous amplitude (i.e., envelope) of a stimulus. These have furthermore demonstrated that such coding required and was optimal for a nonzero level of neural variability. However, a theoretical understanding of these results is still lacking. Here we provide a comprehensive theoretical framework explaining these experimental findings. Specifically, we use linear response theory to derive an expression relating the correlation coefficient to the instantaneous stimulus amplitude, which takes into account key single-neuron properties such as firing rate and variability as quantified by the coefficient of variation. The theoretical prediction was in excellent agreement with numerical simulations of various integrate-and-fire type neuron models for various parameter values. Further, we demonstrate a form of stochastic resonance as optimal coding of stimulus variance by correlated activity occurs for a nonzero value of noise intensity. Thus, our results provide a theoretical explanation of the phenomenon by which correlated but not single-neuron activity can code for stimulus amplitude and how key single-neuron properties such as firing rate and variability influence such coding. Correlation coding by correlated but not single-neuron activity is thus predicted to be a ubiquitous feature of sensory processing for neurons responding to weak input.

  12. A Parallel Distributed Processing Model of Stimulus-Stimulus and Stimulus-Response Compatibility.

    Science.gov (United States)

    Huazhong, Harry Zhang; Zhang, Jun; Kornblum, Sylvan

    1999-01-01

    Proposes a parallel distributed-processing (PDP) model to account for choice-reaction-time performance in diverse cognitive and perceptual tasks that are interrelated in terms of stimulus-stimulus and stimulus-response overlap. Simulation results support the PDP model. (SLD)

  13. Measuring the Environmental Sustainability Performance of Global Supply Chains: a Multi-Regional Input-Output analysis for Carbon, Sulphur Oxide and Water Footprints

    OpenAIRE

    Acquaye, A.; Feng, K; Oppon, E.; Salhi, S.; Ibn-Mohammed, T.; Genovese, A.; Hubacek, K. (Prof. Dr.)

    2016-01-01

    Measuring the performance of what an environmentally sustainable supply chain has become a challenge despite the convergence of the underlining principles of sustainable supply chain management. This challenge is exacerbated by the fact that supply chains are inherently dynamic and complex and also because multiple measures can be used to characterize performances. \\ud By identifying some of the critical issues in the literature regarding performance measurements, this paper contributes to th...

  14. Neural Correlates of Stimulus Reportability

    OpenAIRE

    Hulme, Oliver J.; Friston, Karl F.; Zeki, Semir

    2009-01-01

    Most experiments on the “neural correlates of consciousness” employ stimulus reportability as an operational definition of what is consciously perceived. The interpretation of such experiments therefore depends critically on understanding the neural basis of stimulus reportability. Using a high volume of fMRI data, we investigated the neural correlates of stimulus reportability using a partial report object detection paradigm. Subjects were presented with a random array of circularly arranged...

  15. Neural correlates of stimulus reportability.

    Science.gov (United States)

    Hulme, Oliver J; Friston, Karl F; Zeki, Semir

    2009-08-01

    Most experiments on the "neural correlates of consciousness" employ stimulus reportability as an operational definition of what is consciously perceived. The interpretation of such experiments therefore depends critically on understanding the neural basis of stimulus reportability. Using a high volume of fMRI data, we investigated the neural correlates of stimulus reportability using a partial report object detection paradigm. Subjects were presented with a random array of circularly arranged disc-stimuli and were cued, after variable delays (following stimulus offset), to report the presence or absence of a disc at the cued location, using variable motor actions. By uncoupling stimulus processing, decision, and motor response, we were able to use signal detection theory to deconstruct the neural basis of stimulus reportability. We show that retinotopically specific responses in the early visual cortex correlate with stimulus processing but not decision or report; a network of parietal/temporal regions correlates with decisions but not stimulus presence, whereas classical motor regions correlate with report. These findings provide a basic framework for understanding the neural basis of stimulus reportability without the theoretical burden of presupposing a relationship between reportability and consciousness.

  16. Optimal stimulus shapes for neuronal excitation.

    Directory of Open Access Journals (Sweden)

    Daniel B Forger

    2011-07-01

    Full Text Available An important problem in neuronal computation is to discern how features of stimuli control the timing of action potentials. One aspect of this problem is to determine how an action potential, or spike, can be elicited with the least energy cost, e.g., a minimal amount of applied current. Here we show in the Hodgkin & Huxley model of the action potential and in experiments on squid giant axons that: 1 spike generation in a neuron can be highly discriminatory for stimulus shape and 2 the optimal stimulus shape is dependent upon inputs to the neuron. We show how polarity and time course of post-synaptic currents determine which of these optimal stimulus shapes best excites the neuron. These results are obtained mathematically using the calculus of variations and experimentally using a stochastic search methodology. Our findings reveal a surprising complexity of computation at the single cell level that may be relevant for understanding optimization of signaling in neurons and neuronal networks.

  17. Understanding smell--the olfactory stimulus problem.

    Science.gov (United States)

    Auffarth, Benjamin

    2013-09-01

    The main problem with sensory processing is the difficulty in relating sensory input to physiological responses and perception. This is especially problematic at higher levels of processing, where complex cues elicit highly specific responses. In olfaction, this relationship is particularly obfuscated by the difficulty of characterizing stimulus statistics and perception. The core questions in olfaction are hence the so-called stimulus problem, which refers to the understanding of the stimulus, and the structure-activity and structure-odor relationships, which refer to the molecular basis of smell. It is widely accepted that the recognition of odorants by receptors is governed by the detection of physico-chemical properties and that the physical space is highly complex. Not surprisingly, ideas differ about how odor stimuli should be classified and about the very nature of information that the brain extracts from odors. Even though there are many measures for smell, there is none that accurately describes all aspects of it. Here, we summarize recent developments in the understanding of olfaction. We argue that an approach to olfactory function where information processing is emphasized could contribute to a high degree to our understanding of smell as a perceptual phenomenon emerging from neural computations. Further, we argue that combined analysis of the stimulus, biology, physiology, and behavior and perception can provide new insights into olfactory function. We hope that the reader can use this review as a competent guide and overview of research activities in olfactory physiology, psychophysics, computation, and psychology. We propose avenues for research, particularly in the systematic characterization of receptive fields and of perception. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. [The P300 based brain-computer interface: effect of stimulus position in a stimulus train].

    Science.gov (United States)

    Ganin, I P; Shishkin, S L; Kochetova, A G; Kaplan, A Ia

    2012-01-01

    The P300 brain-computer interface (BCI) is currently the most efficient BCI. This interface is based on detection of the P300 wave of the brain potentials evoked when a symbol related to the intended input is highlighted. To increase operation speed of the P300 BCI, reduction of the number of stimuli repetitions is needed. This reduction leads to increase of the relative contribution to the input symbol detection from the reaction to the first target stimulus. It is known that the event-related potentials (ERP) to the first stimulus presentations can be different from the ERP to stimuli presented latter. In particular, the amplitude of responses to the first stimulus presentations is often increased, which is beneficial for their recognition by the BCI. However, this effect was not studied within the BCI framework. The current study examined the ERP obtained from healthy participants (n = 14) in the standard P300 BCI paradigm using 10 trials, as well as in the modified P300 BCI with stimuli presented on moving objects in triple-trial (n = 6) and single-trial (n = 6) stimulation modes. Increased ERP amplitude was observed in response to the first target stimuli in both conditions, as well as in the single-trial mode comparing to triple-trial. We discuss the prospects of using the specific features of the ERP to first stimuli and the single-trial ERP for optimizing the high-speed modes in the P300 BCIs.

  19. Sustained increase of spontaneous input and spike transfer in the CA3-CA1 pathway following long term potentiation in vivo

    Directory of Open Access Journals (Sweden)

    Oscar eHerreras

    2012-10-01

    Full Text Available Long term potentiation (LTP is commonly used to study synaptic plasticity but the associated changes in the spontaneous activity of individual neurons or the computational properties of neural networks in vivo remain largely unclear. The multisynaptic origin of spontaneous spikes makes difficult estimating the impact of a particular potentiated input. Accordingly, we adopted an approach that isolates pathway-specific postsynaptic activity from raw local field potentials (LFPs in the rat hippocampus in order to study the effects of LTP on ongoing spike transfer between cell pairs in the CA3-CA1 pathway. CA1 Schaffer-specific LFPs elicited by spontaneous clustered firing of CA3 pyramidal cells involved a regular succession of elementary micro-field-EPSPs (gamma-frequency that fired spikes in CA1 units. LTP increased the amplitude but not the frequency of these ongoing excitatory quanta. Also, the proportion of Schaffer-driven spikes in both CA1 pyramidal cells and interneurons increased in a cell-specific manner only in previously connected CA3-CA1 cell pairs, i.e., when the CA3 pyramidal cell had shown pre-LTP significant correlation with firing of a CA1 unit and potentiated spike-triggered average of Schaffer LFPs following LTP. Moreover, LTP produced subtle reorganization of presynaptic CA3 cell assemblies. These findings show effective enhancement of pathway specific ongoing activity which leads to increased spike transfer in potentiated segments of a network. These indicate that plastic phenomena induced by external protocols may intensify spontaneous information flow across specific channels as proposed in transsynaptic propagation of plasticity and synfire chain hypotheses that may be the substrate for different types of memory involving multiple brain structures.

  20. Saccadic modulation of stimulus processing in primary visual cortex

    Science.gov (United States)

    McFarland, James M.; Bondy, Adrian G.; Saunders, Richard C.; Cumming, Bruce G.; Butts, Daniel A.

    2015-01-01

    Saccadic eye movements play a central role in primate vision. Yet, relatively little is known about their effects on the neural processing of visual inputs. Here we examine this question in primary visual cortex (V1) using receptive-field-based models, combined with an experimental design that leaves the retinal stimulus unaffected by saccades. This approach allows us to analyse V1 stimulus processing during saccades with unprecedented detail, revealing robust perisaccadic modulation. In particular, saccades produce biphasic firing rate changes that are composed of divisive gain suppression followed by an additive rate increase. Microsaccades produce similar, though smaller, modulations. We furthermore demonstrate that this modulation is likely inherited from the LGN, and is driven largely by extra-retinal signals. These results establish a foundation for integrating saccades into existing models of visual cortical stimulus processing, and highlight the importance of studying visual neuron function in the context of eye movements. PMID:26370359

  1. Two improved methods for testing ADC parametric faults by digital input signals

    NARCIS (Netherlands)

    Sheng, Xiaoqin; Kerkhoff, Hans G.

    2009-01-01

    In this paper, two improved methods are presented extending our previous work. The first one improves the results by adjusting the voltage levels of the input pulse wave stimulus. Compared with the sine wave input stimulus, the four-level pulse wave can detect even more faulty cases with the offset

  2. StimDuino: an Arduino-based electrophysiological stimulus isolator.

    Science.gov (United States)

    Sheinin, Anton; Lavi, Ayal; Michaelevski, Izhak

    2015-03-30

    Electrical stimulus isolator is a widely used device in electrophysiology. The timing of the stimulus application is usually automated and controlled by the external device or acquisition software; however, the intensity of the stimulus is adjusted manually. Inaccuracy, lack of reproducibility and no automation of the experimental protocol are disadvantages of the manual adjustment. To overcome these shortcomings, we developed StimDuino, an inexpensive Arduino-controlled stimulus isolator allowing highly accurate, reproducible automated setting of the stimulation current. The intensity of the stimulation current delivered by StimDuino is controlled by Arduino, an open-source microcontroller development platform. The automatic stimulation patterns are software-controlled and the parameters are set from Matlab-coded simple, intuitive and user-friendly graphical user interface. The software also allows remote control of the device over the network. Electrical current measurements showed that StimDuino produces the requested current output with high accuracy. In both hippocampal slice and in vivo recordings, the fEPSP measurements obtained with StimDuino and the commercial stimulus isolators showed high correlation. Commercial stimulus isolators are manually managed, while StimDuino generates automatic stimulation patterns with increasing current intensity. The pattern is utilized for the input-output relationship analysis, necessary for assessment of excitability. In contrast to StimuDuino, not all commercial devices are capable for remote control of the parameters and stimulation process. StimDuino-generated automation of the input-output relationship assessment eliminates need for the current intensity manually adjusting, improves stimulation reproducibility, accuracy and allows on-site and remote control of the stimulation parameters. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Sustainable processing

    DEFF Research Database (Denmark)

    Kristensen, Niels Heine

    2004-01-01

    Kristensen_NH and_Beck A: Sustainable processing. In Otto Schmid, Alexander Beck and Ursula Kretzschmar (Editors) (2004): Underlying Principles in Organic and "Low-Input Food" Processing - Literature Survey. Research Institute of Organic Agriculture FiBL, CH-5070 Frick, Switzerland. ISBN 3-906081-58-3...

  4. Temporal and spectral profiles of stimulus-stimulus and stimulus-response conflict processing.

    Science.gov (United States)

    Wang, Kai; Li, Qi; Zheng, Ya; Wang, Hongbin; Liu, Xun

    2014-04-01

    The ability to detect and resolve conflict is an essential function of cognitive control. Laboratory studies often use stimulus-response-compatibility (SRC) tasks to examine conflict processing in order to elucidate the mechanism and modular organization of cognitive control. Inspired by two influential theories regarding cognitive control, the conflict monitoring theory (Botvinick, Braver, Barch, Carter, & Cohen, 2001) and dimensional overlap taxonomy (Kornblum, Hasbroucq, & Osman, 1990), we explored the temporal and spectral similarities and differences between processing of stimulus-stimulus (S-S) and stimulus-response (S-R) conflicts with event related potential (ERP) and time-frequency measures. We predicted that processing of S-S conflict starts earlier than that of S-R conflict and that the two types of conflict may involve different frequency bands. Participants were asked to perform two parallel SRC tasks, both combining the Stroop task (involving S-S conflict) and Simon task (involving S-R conflict). ERP results showed pronounced SRC effects (incongruent vs. congruent) on N2 and P3 components for both S-S and S-R conflicts. In both tasks, SRC effects of S-S conflict took place earlier than those of S-R conflict. Time-frequency analysis revealed that both types of SRC effects modulated theta and alpha bands, while S-R conflict effects additionally modulated power in the beta band. These results indicated that although S-S and S-R conflict processing shared considerable ERP and time-frequency properties, they differed in temporal and spectral dynamics. We suggest that the modular organization of cognitive control should take both commonality and distinction of S-S and S-R conflict processing into consideration. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Working memory accuracy for multiple targets is driven by reward expectation and stimulus contrast with different time-courses

    NARCIS (Netherlands)

    Klink, P. Christiaan; Jeurissen, Danique; Theeuwes, Jan; Denys, Damiaan; Roelfsema, Pieter R.

    2017-01-01

    The richness of sensory input dictates that the brain must prioritize and select information for further processing and storage in working memory. Stimulus salience and reward expectations influence this prioritization but their relative contributions and underlying mechanisms are poorly understood.

  6. Stimulus-dependent maximum entropy models of neural population codes.

    Directory of Open Access Journals (Sweden)

    Einat Granot-Atedgi

    Full Text Available Neural populations encode information about their stimulus in a collective fashion, by joint activity patterns of spiking and silence. A full account of this mapping from stimulus to neural activity is given by the conditional probability distribution over neural codewords given the sensory input. For large populations, direct sampling of these distributions is impossible, and so we must rely on constructing appropriate models. We show here that in a population of 100 retinal ganglion cells in the salamander retina responding to temporal white-noise stimuli, dependencies between cells play an important encoding role. We introduce the stimulus-dependent maximum entropy (SDME model-a minimal extension of the canonical linear-nonlinear model of a single neuron, to a pairwise-coupled neural population. We find that the SDME model gives a more accurate account of single cell responses and in particular significantly outperforms uncoupled models in reproducing the distributions of population codewords emitted in response to a stimulus. We show how the SDME model, in conjunction with static maximum entropy models of population vocabulary, can be used to estimate information-theoretic quantities like average surprise and information transmission in a neural population.

  7. Stimulus conflict triggers behavioral avoidance.

    Science.gov (United States)

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance.

  8. Stimulus ambiguity elicits response conflict.

    Science.gov (United States)

    Szmalec, Arnaud; Verbruggen, Frederick; Vandierendonck, André; De Baene, Wouter; Verguts, Tom; Notebaert, Wim

    2008-04-18

    Conflict monitoring theory [M.M. Botvinick, T. Braver, D. Barch, C. Carter, J.D. Cohen, Conflict monitoring and cognitive control, Psychol. Rev. 108 (2001) 625-652] assumes that perceptual ambiguity among choice stimuli elicits response conflict in choice reaction. It hence predicts that response conflict is also involved in elementary variants of choice reaction time (RT) tasks, i.e., those variants that, by contrast with the Stroop task or the Go/No-Go task for instance, are rarely associated with cognitive control. In order to test this prediction, an experiment was designed in which participants performed a simple RT task and a regular between-hand 2-choice RT task under three different levels of stimulus ambiguity. The data show that response conflict, as measured by the N2 component of the event-related brain potential (ERP), was elicited in the 2-choice RT task but not in the simple RT task and that the degree of response conflict in the 2-choice RT task was a function of stimulus ambiguity. These results show that response conflict is also present in a regular choice RT task which is traditionally not considered to be a measure of cognitive conflict.

  9. Transformation of stimulus correlations by the retina.

    Directory of Open Access Journals (Sweden)

    Kristina D Simmons

    Full Text Available Redundancies and correlations in the responses of sensory neurons may seem to waste neural resources, but they can also carry cues about structured stimuli and may help the brain to correct for response errors. To investigate the effect of stimulus structure on redundancy in retina, we measured simultaneous responses from populations of retinal ganglion cells presented with natural and artificial stimuli that varied greatly in correlation structure; these stimuli and recordings are publicly available online. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were modestly more correlated than in response to white noise checkerboards, but they were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio-temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of pairwise correlations across stimuli where receptive field measurements were possible.

  10. Stimulus number, duration and intensity encoding in randomly connected attractor networks with synaptic depression

    Directory of Open Access Journals (Sweden)

    Paul eMiller

    2013-05-01

    Full Text Available Randomly connected recurrent networks of excitatory groups of neurons can possess a multitude of attractor states. When the internal excitatory synapses of these networks are depressing, the attractor states can be destabilized with increasing input. This leads to an itinerancy, where with either repeated transient stimuli, or increasing duration of a single stimulus, the network activity advances through sequences of attractor states. We find that the resulting network state, which persists beyond stimulus offset, can encode the number of stimuli presented via a distributed representation of neural activity with non-monotonic tuning curves for most neurons. Increased duration of a single stimulus is encoded via different distributed representations, so unlike an integrator, the network distinguishes separate successive presentations of a short stimulus from a single presentation of a longer stimulus with equal total duration. Moreover, different amplitudes of stimulus cause new, distinct activity patterns, such that changes in stimulus number, duration and amplitude can be distinguished from each other. These properties of the network depend on dynamic depressing synapses, as they disappear if synapses are static. Thus short-term synaptic depression allows a network to store separately the different dynamic properties of a spatially constant stimulus.

  11. Sustainability: An Overview.

    Science.gov (United States)

    Wormsley, W. E.

    1990-01-01

    This article introduces a group of six papers on sustainability of programs for visually handicapped persons in developing countries. Sustainability is discussed from an anthropological perspective, noting the importance of a social soundness analysis and a social impact assessment, enemies of sustainability, and the need for broad local input in…

  12. Carving Executive Control At Its Joints: Working Memory Capacity Predicts Stimulus-Stimulus, But Not Stimulus-Response, Conflict

    OpenAIRE

    Meier, Matt E.; Kane, Michael J.

    2015-01-01

    Three experiments examined the relation between working memory capacity (WMC) and two different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (SR) interference. Our goal was to test whether WMC’s relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict), response-selection processes (captured by S-R conflict), or both. In Experiment 1, subjects completed a single task presenting both S-S and S-R conflict tria...

  13. Stimulus Probability Effects in Absolute Identification

    Science.gov (United States)

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  14. Effect of stimulus width on simultaneous contrast

    Directory of Open Access Journals (Sweden)

    Veronica Shi

    2013-09-01

    Full Text Available Perceived brightness of a stimulus depends on the background against which the stimulus is set, a phenomenon known as simultaneous contrast. For instance, the same gray stimulus can look light against a black background or dark against a white background. Here we quantified the perceptual strength of simultaneous contrast as a function of stimulus width. Previous studies have reported that wider stimuli result in weaker simultaneous contrast, whereas narrower stimuli result in stronger simultaneous contrast. However, no previous research has quantified this relationship. Our results show a logarithmic relationship between stimulus width and perceived brightness. This relationship is well matched by the normalized output of a Difference-of-Gaussians (DOG filter applied to stimuli of varied widths.

  15. Exergy sustainability.

    Energy Technology Data Exchange (ETDEWEB)

    Robinett, Rush D. III (.; ); Wilson, David Gerald; Reed, Alfred W.

    2006-05-01

    Exergy is the elixir of life. Exergy is that portion of energy available to do work. Elixir is defined as a substance held capable of prolonging life indefinitely, which implies sustainability of life. In terms of mathematics and engineering, exergy sustainability is defined as the continuous compensation of irreversible entropy production in an open system with an impedance and capacity-matched persistent exergy source. Irreversible and nonequilibrium thermodynamic concepts are combined with self-organizing systems theories as well as nonlinear control and stability analyses to explain this definition. In particular, this paper provides a missing link in the analysis of self-organizing systems: a tie between irreversible thermodynamics and Hamiltonian systems. As a result of this work, the concept of ''on the edge of chaos'' is formulated as a set of necessary and sufficient conditions for stability and performance of sustainable systems. This interplay between exergy rate and irreversible entropy production rate can be described as Yin and Yang control: the dialectic synthesis of opposing power flows. In addition, exergy is shown to be a fundamental driver and necessary input for sustainable systems, since exergy input in the form of power is a single point of failure for self-organizing, adaptable systems.

  16. How Stimulus and Task Complexity Affect Monitoring in High-Functioning Adults with Autism Spectrum Disorder

    Science.gov (United States)

    Koolen, Sophieke; Vissers, Constance Th. W. M.; Egger, Jos I. M.; Verhoeven, Ludo

    2014-01-01

    The present study examined whether individuals with autism spectrum disorder (ASD) are able to update and monitor working memory representations of visual input, and whether performance is influenced by stimulus and task complexity. 15 high-functioning adults with ASD and 15 controls were asked to allocate either elements of abstract figures or…

  17. Input parameters and scenarios, including economic inputs

    DEFF Research Database (Denmark)

    Boklund, Anette; Hisham Beshara Halasa, Tariq

    2012-01-01

    to day 8 after the herd was infected, and increased to 1 after day 8. The outputs from the epidemiological models were used as inputs in an economic model to calculate costs and losses for each epidemic. The costs of an epidemic were divided into direct and indirect costs. The direct costs consisted...

  18. Conditioned pain modulation is minimally influenced by cognitive evaluation or imagery of the conditioning stimulus

    Directory of Open Access Journals (Sweden)

    Bernaba M

    2014-11-01

    Full Text Available Mario Bernaba, Kevin A Johnson, Jiang-Ti Kong, Sean MackeyStanford Systems Neuroscience and Pain Laboratory, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USAPurpose: Conditioned pain modulation (CPM is an experimental approach for probing endogenous analgesia by which one painful stimulus (the conditioning stimulus may inhibit the perceived pain of a subsequent stimulus (the test stimulus. Animal studies suggest that CPM is mediated by a spino–bulbo–spinal loop using objective measures such as neuronal firing. In humans, pain ratings are often used as the end point. Because pain self-reports are subject to cognitive influences, we tested whether cognitive factors would impact on CPM results in healthy humans.Methods: We conducted a within-subject, crossover study of healthy adults to determine the extent to which CPM is affected by 1 threatening and reassuring evaluation and 2 imagery alone of a cold conditioning stimulus. We used a heat stimulus individualized to 5/10 on a visual analog scale as the testing stimulus and computed the magnitude of CPM by subtracting the postconditioning rating from the baseline pain rating of the heat stimulus.Results: We found that although evaluation can increase the pain rating of the conditioning stimulus, it did not significantly alter the magnitude of CPM. We also found that imagery of cold pain alone did not result in statistically significant CPM effect.Conclusion: Our results suggest that CPM is primarily dependent on sensory input, and that the cortical processes of evaluation and imagery have little impact on CPM. These findings lend support for CPM as a useful tool for probing endogenous analgesia through subcortical mechanisms.Keywords: conditioned pain modulation, endogenous analgesia, evaluation, imagery, cold presser test, CHEPS, contact heat-evoked potential stimulator

  19. MDS MIC Catalog Inputs

    Science.gov (United States)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  20. Occlusion for stimulus deprivation amblyopia

    Science.gov (United States)

    Antonio-Santos, Aileen; Vedula, Satyanarayana S; Hatt, Sarah R; Powell, Christine

    2014-01-01

    Background Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In developed countries, most patients present under the age of one year; in less developed parts of the world patients are likely to be older at the time of presentation. The mainstay of treatment is removal of the cataract and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results. Objectives Our objective was to evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes. Where data were available, we also planned to examine evidence of any dose response effect and to assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), the Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2013), PubMed (January 1946 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 October 2013. Selection criteria We planned

  1. EEG Differentiation Analysis and Stimulus Set Meaningfulness.

    Science.gov (United States)

    Mensen, Armand; Marshall, William; Tononi, Giulio

    2017-01-01

    A set of images can be considered as meaningfully different for an observer if they can be distinguished phenomenally from one another. Each phenomenal difference must be supported by some neurophysiological differences. Differentiation analysis aims to quantify neurophysiological differentiation evoked by a given set of stimuli to assess its meaningfulness to the individual observer. As a proof of concept using high-density EEG, we show increased neurophysiological differentiation for a set of natural, meaningfully different images in contrast to another set of artificially generated, meaninglessly different images in nine participants. Stimulus-evoked neurophysiological differentiation (over 257 channels, 800 ms) was systematically greater for meaningful vs. meaningless stimulus categories both at the group level and for individual subjects. Spatial breakdown showed a central-posterior peak of differentiation, consistent with the visual nature of the stimulus sets. Temporal breakdown revealed an early peak of differentiation around 110 ms, prominent in the central-posterior region; and a later, longer-lasting peak at 300-500 ms that was spatially more distributed. The early peak of differentiation was not accompanied by changes in mean ERP amplitude, whereas the later peak was associated with a higher amplitude ERP for meaningful images. An ERP component similar to visual-awareness-negativity occurred during the nadir of differentiation across all image types. Control stimulus sets and further analysis indicate that changes in neurophysiological differentiation between meaningful and meaningless stimulus sets could not be accounted for by spatial properties of the stimuli or by stimulus novelty and predictability.

  2. Spiking neural circuits with dendritic stimulus processors : encoding, decoding, and identification in reproducing kernel Hilbert spaces.

    Science.gov (United States)

    Lazar, Aurel A; Slutskiy, Yevgeniy B

    2015-02-01

    We present a multi-input multi-output neural circuit architecture for nonlinear processing and encoding of stimuli in the spike domain. In this architecture a bank of dendritic stimulus processors implements nonlinear transformations of multiple temporal or spatio-temporal signals such as spike trains or auditory and visual stimuli in the analog domain. Dendritic stimulus processors may act on both individual stimuli and on groups of stimuli, thereby executing complex computations that arise as a result of interactions between concurrently received signals. The results of the analog-domain computations are then encoded into a multi-dimensional spike train by a population of spiking neurons modeled as nonlinear dynamical systems. We investigate general conditions under which such circuits faithfully represent stimuli and demonstrate algorithms for (i) stimulus recovery, or decoding, and (ii) identification of dendritic stimulus processors from the observed spikes. Taken together, our results demonstrate a fundamental duality between the identification of the dendritic stimulus processor of a single neuron and the decoding of stimuli encoded by a population of neurons with a bank of dendritic stimulus processors. This duality result enabled us to derive lower bounds on the number of experiments to be performed and the total number of spikes that need to be recorded for identifying a neural circuit.

  3. PLEXOS Input Data Generator

    Energy Technology Data Exchange (ETDEWEB)

    2017-02-01

    The PLEXOS Input Data Generator (PIDG) is a tool that enables PLEXOS users to better version their data, automate data processing, collaborate in developing inputs, and transfer data between different production cost modeling and other power systems analysis software. PIDG can process data that is in a generalized format from multiple input sources, including CSV files, PostgreSQL databases, and PSS/E .raw files and write it to an Excel file that can be imported into PLEXOS with only limited manual intervention.

  4. Responses of Human Medial Temporal Lobe Neurons Are Modulated by Stimulus Repetition

    Science.gov (United States)

    Pedreira, Carlos; Mormann, Florian; Kraskov, Alexander; Cerf, Moran; Fried, Itzhak; Koch, Christof

    2010-01-01

    Recent studies have reported the presence of single neurons with strong responses to visual inputs in the human medial temporal lobe. Here we show how repeated stimulus presentation—photos of celebrities and familiar individuals, landmark buildings, animals, and objects—modulates the firing rate of these cells: a consistent decrease in the neural activity was registered as images were repeatedly shown during experimental sessions. The effect of repeated stimulus presentation was not the same for all medial temporal lobe areas. These findings are consistent with the view that medial temporal lobe neurons link visual percepts to declarative memory. PMID:19864436

  5. Electrophysiological correlates of changes in reaction time based on stimulus intensity.

    Directory of Open Access Journals (Sweden)

    Bimal Lakhani

    Full Text Available Although reaction time is commonly used as an indicator of central nervous system integrity, little is currently understood about the mechanisms that determine processing time. In the current study, we are interested in determining the differences in electrophysiological events associated with significant changes in reaction time that could be elicited by changes in stimulus intensity. The primary objective is to assess the effect of increasing stimulus intensity on the latency and amplitude of afferent inputs to the somatosensory cortex, and their relation to reaction time.Median nerve stimulation was applied to the non-dominant hand of 12 healthy young adults at two different stimulus intensities (HIGH & LOW. Participants were asked to either press a button as fast as possible with their dominant hand or remain quiet following the stimulus. Electroencephalography was used to measure somatosensory evoked potentials (SEPs and event related potentials (ERPs. Electromyography from the flexor digitorum superficialis of the button-pressing hand was used to assess reaction time. Response time was the time of button press.Reaction time and response time were significantly shorter following the HIGH intensity stimulus compared to the LOW intensity stimulus. There were no differences in SEP (N20 & P24 peak latencies and peak-to-peak amplitude for the two stimulus intensities. ERPs, locked to response time, demonstrated a significantly larger pre-movement negativity to positivity following the HIGH intensity stimulus over the Cz electrode.This work demonstrates that rapid reaction times are not attributable to the latency of afferent processing from the stimulated site to the somatosensory cortex, and those latency reductions occur further along the sensorimotor transformation pathway. Evidence from ERPs indicates that frontal planning areas such as the supplementary motor area may play a role in transforming the elevated sensory volley from the

  6. ADC multi-site test based on a pre-test with digital input stimulus

    NARCIS (Netherlands)

    Sheng, Xiaoqin; Metra, C.; Kerkhoff, Hans G.; Zjajo, Amir; Gronthoud, Guido

    2012-01-01

    This paper describes two novel algorithms based on the time-modulo reconstruction method intended for detection of the parametric faults in analogue-to-digital converters (ADC). In both algorithms, a pulse signal, in its slightly adapted form to allow sufficient time for converter settling, is taken

  7. Algorithms for ADC multi-site test with digital input stimulus

    NARCIS (Netherlands)

    Sheng, Xiaoqin; Kerkhoff, Hans G.; Zjajo, Amir; Gronthoud, Guido

    2009-01-01

    This paper reports two novel algorithms based on time-modulo reconstruction method intended for detection of the parametric faults in analogue-to-digital converters (ADC). In both algorithms, a pulse signal, in its slightly adapted form to allow sufficient time for converter settling, is taken as

  8. ERP components related to stimulus selection processes.

    Science.gov (United States)

    Paz-Caballero, M D; García-Austt, E

    1992-05-01

    Event-related potential (ERP) components associated with target stimulus selection in a double discrimination visual task were studied. The experimental paradigm consisted in the presentation of low intensity stimuli that varied according to two physical features: geometrical form (squares and circles) and location (a spot in different positions inside the stimulus). Subjects performed 3 tasks on these stimuli: control task in which they looked passively at the stimuli, and 2 discrimination tasks, in which they had to respond to a certain stimulus (a specific conjunction of form and spot location). The early components (P1 and N1) obtained in the control and discrimination tasks were associated with sensory analysis of simple stimulus features. Relevance of a particular feature modified the latency and/or the area of these components. The longer-latency components (N2 and P3) were elicited only in the discrimination tasks. N2 was associated with target stimulus selection because its area was significantly larger for target stimuli and because its "offset" latency correlated with choice reaction time. Results are discussed and contrasted with various models of target selection.

  9. Defining the stimulus--a memoir.

    Science.gov (United States)

    Terrace, Herbert

    2010-02-01

    The eminent psychophysicist, S.S. Stevens, once remarked that, "the basic problem of psychology was the definition of the stimulus" (Stevens, 1951, p. 46). By expanding the traditional definition of the stimulus, the study of animal learning has metamorphosed into animal cognition. The main impetus for that change was the recognition that it is often necessary to postulate a representation between the traditional S and R of learning theory. Representations allow a subject to represent a stimulus it learned previously that is currently absent. Thus, in delayed matching-to-sample, one has to assume that a subject responds to a representation of the sample during test if it responds correctly. Other examples, to name but a few, include concept formation, spatial memory, serial memory, learning a numerical rule, imitation and metacognition. Whereas a representation used to be regarded as a mentalistic phenomenon that was unworthy of scientific inquiry, it can now be operationally defined. To accommodate representations, the traditional discriminative stimulus has to be expanded to allow for the role of representations. The resulting composite can account for a significantly larger portion of the variance of performance measures than the exteroceptive stimulus could by itself. Copyright 2009 Elsevier B.V. All rights reserved.

  10. Input coding for neuro-electronic hybrid systems.

    Science.gov (United States)

    George, Jude Baby; Abraham, Grace Mathew; Singh, Katyayani; Ankolekar, Shreya M; Amrutur, Bharadwaj; Sikdar, Sujit Kumar

    2014-12-01

    Liquid State Machines have been proposed as a framework to explore the computational properties of neuro-electronic hybrid systems (Maass et al., 2002). Here the neuronal culture implements a recurrent network and is followed by an array of linear discriminants implemented using perceptrons in electronics/software. Thus in this framework, it is desired that the outputs of the neuronal network, corresponding to different inputs, be linearly separable. Previous studies have demonstrated this by either using only a small set of input stimulus patterns to the culture (Hafizovic et al., 2007), large number of input electrodes (Dockendorf et al., 2009) or by using complex schemes to post-process the outputs of the neuronal culture prior to linear discriminance (Ortman et al., 2011). In this study we explore ways to temporally encode inputs into stimulus patterns using a small set of electrodes such that the neuronal culture's output can be directly decoded by simple linear discriminants based on perceptrons. We demonstrate that network can detect the timing and order of firing of inputs on multiple electrodes. Based on this, we demonstrate that the neuronal culture can be used as a kernel to transform inputs which are not linearly separable in a low dimensional space, into outputs in a high dimension where they are linearly separable. Thus simple linear discriminants can now be directly connected to outputs of the neuronal culture and allow for implementation of any function for such a hybrid system. Copyright © 2014. Published by Elsevier Ireland Ltd.

  11. Estimating latency from inhibitory input

    DEFF Research Database (Denmark)

    Levakova, Marie; Ditlevsen, Susanne; Lansky, Petr

    2014-01-01

    Stimulus response latency is the time period between the presentation of a stimulus and the occurrence of a change in the neural firing evoked by the stimulation. The response latency has been explored and estimation methods proposed mostly for excitatory stimuli, which means that the neuron reac...

  12. Stimulus generalization of a positive conditioned reinforcer.

    Science.gov (United States)

    THOMAS, D R; WILLIAMS, J L

    1963-07-12

    Stimulus generalization has been observed for discriminative, eliciting, and emotional functions of stimuli. In our study, in order to investigate the generalization of the reinforcing function of stimuli, pigeons were trained in a Skinner box to peck at an unlighted key to obtain aperiodic, brief exposures of light at a wavelength of 550 mmicro, the positive conditioned reinforcer, which was immediately followed by food reward. Testing in extinction, we obtained generalization gradients for the number of responses and the time the pigeons expended to produce exposures on the unlighted key of 550 mmicro, 530 mmicro) 510 mmicro, or no light. This finding suggests that stimulus generalization occurs with all functions of stimuli.

  13. Carving Executive Control At Its Joints: Working Memory Capacity Predicts Stimulus-Stimulus, But Not Stimulus-Response, Conflict

    Science.gov (United States)

    Meier, Matt E.; Kane, Michael J.

    2015-01-01

    Three experiments examined the relation between working memory capacity (WMC) and two different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (SR) interference. Our goal was to test whether WMC’s relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict), response-selection processes (captured by S-R conflict), or both. In Experiment 1, subjects completed a single task presenting both S-S and S-R conflict trials, plus trials that combined the two conflict types. We limited ostensible goal-maintenance contributions to performance by requiring the same goal for all trial types and by presenting frequent conflict trials that reinforced the goal. WMC predicted resolution of S-S conflict as expected: Higher-WMC subjects showed reduced response time interference. Although WMC also predicted S-R interference, here, higher-WMC subjects showed increased error interference. Experiment 2A replicated these results in a version of the conflict task without combined S-S/S-R trials. Experiment 2B increased the proportion of congruent (non-conflict) trials to promote reliance on goal-maintenance processes. Here, higher-WMC subjects resolved both S-S and S-R conflict more successfully than did lower-WMC subjects. The results were consistent with Kane and Engle’s (2003) two-factor theory of cognitive control, according to which WMC predicts executive-task performance through goal-maintenance and conflict-resolution processes. However, the present results add specificity to the account by suggesting that higher-WMC subjects better resolve cognitive conflict because they more efficiently select relevant stimulus features against irrelevant, distracting ones. PMID:26120774

  14. Rich input i engelskundervisningen

    DEFF Research Database (Denmark)

    Melgaard, Bente; Guttesen, Maria Josephine; Jacobsen, Susanne Karen

    2017-01-01

    Der er mange gode grunde til at bruge autentiske tekster i engelskundervisningen på alle niveauer. Eleverne skal i engelskundervisningen stifte bekendtskab med et varieret input på fremmedsproget, og det at læse autentiske tekster er et møde med sprog som målrettet målsprogsbrugere, og giver...

  15. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...

  16. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    2015-01-01

    sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...

  17. ColloInputGenerator

    DEFF Research Database (Denmark)

    2013-01-01

    This is a very simple program to help you put together input files for use in Gries' (2007) R-based collostruction analysis program. It basically puts together a text file with a frequency list of lexemes in the construction and inserts a column where you can add the corpus frequencies. It requir...

  18. Stimulus-classification and stimulus-action associations: Effects of repetition learning and durability.

    Science.gov (United States)

    Moutsopoulou, Karolina; Yang, Qing; Desantis, Andrea; Waszak, Florian

    2015-01-01

    It has been shown that acquired stimulus-response bindings result from at least two types of associations from the stimulus to the task (stimulus-task or stimulus-classification; S-C) and from the stimulus to the motor response (stimulus-response or stimulus-action; S-A). These types of associations have been shown to independently affect behaviour. This finding suggests that they are processed in different pathways or different parts of a pathway at the neural level. Here we test a hypothesis that such associations may be differentially affected by repetition learning and that such effects may be detected by measuring their durability against overwriting. We show that both S-C and S-A associations are in fact strengthened when learning is boosted by increasing repetitions of the primes. However, the results further suggest that associations between stimuli and actions have less durable effects on behaviour and that the durability of S-C and S-A associations is independent of repetition learning. This is an important finding for the understanding of the underlying mechanisms of associative learning and particularly raises the question of which processes may affect flexibility of learning.

  19. Stimulus Configuration, Classical Conditioning, and Hippocampal Function.

    Science.gov (United States)

    Schmajuk, Nestor A.; DiCarlo, James J.

    1991-01-01

    The participation of the hippocampus in classical conditioning is described in terms of a multilayer network portraying stimulus configuration. A model of hippocampal function is presented, and computer simulations are used to study neural activity in the various brain areas mapped according to the model. (SLD)

  20. Bigrams and the Richness of the Stimulus

    Science.gov (United States)

    Kam, Xuan-Nga Cao; Stoyneshka, Iglika; Tornyova, Lidiya; Fodor, Janet D.; Sakas, William G.

    2008-01-01

    Recent challenges to Chomsky's "poverty of the stimulus" thesis for language acquisition suggest that children's primary data may carry "indirect evidence" about linguistic constructions despite containing no instances of them. Indirect evidence is claimed to suffice for grammar acquisition, without need for innate knowledge. This article reports…

  1. The Poverty of the Mayan Stimulus

    Science.gov (United States)

    Pye, Clifton

    2012-01-01

    Poverty of the stimulus (POS) arguments have instigated considerable debate in the recent linguistics literature. This article uses the comparative method to challenge the logic of POS arguments. Rather than question the premises of POS arguments, the article demonstrates how POS arguments for individual languages lead to a "reductio ad absurdum"…

  2. Economic Stimulus Proposals for 2008: An Analysis

    National Research Council Canada - National Science Library

    Gravelle, Jane G; Hungerford, Thomas L; Labonte, Marc; Weiss, N. E; Whittaker, Julie M

    2008-01-01

    ...) was introduced and passed by the House on January 29. On January 30, the Senate Committee on Finance reported the Economic Stimulus Act of 2008, which contains provisions not included in the House bill, as well as elements that are similar...

  3. Stimulus polarity and conditioning in planaria.

    Science.gov (United States)

    BARNES, C D; KATZUNG, B G

    1963-08-23

    Orientation in the monopolar pulse field used as the unconditioned stimulus was found to influence formation of a conditioned response to light in planarians. Planarians trained while oriented with the head toward the cathode reached maximal response rates rapidly, while those trained while oriented toward the anode showed no evidence of conditioned response formation.

  4. Crisis, Stimulus Package and Migration in China

    NARCIS (Netherlands)

    Csanádi, Maria; Nie, Zihan; Li, Shi

    2015-01-01

    This paper analyzes the short-term and long-term effects that the global economic crisis and the investment priorities of the Chinese Government's stimulus package had on Chinese migrant flows between 2008 and 2014. Combining micro-level household survey data and macro-level statistics, the

  5. Contextual dependencies in a stimulus equivalence paradigm

    NARCIS (Netherlands)

    Dibbets, P.; Maes, J.H.R.; Vossen, J.M.H.

    2002-01-01

    Two experiments with human subjects assessed contextual dependencies in a stimulus equivalence paradigm. Subjects learned to form two sets of stimuli in a matching-to-sample training procedure. Each set was presented against one of two different background colours, the contextual cues. At test, the

  6. A notion of sufficient input

    OpenAIRE

    Bertrand Crettez; Philippe Michel

    2003-01-01

    In this paper, we study a notion of sufficient input, i.e. input that allows to produce at least one unit of output when the other inputs are fixed at any positive level. We show that such an input allows to produce any positive amount of production. The main property of sufficient inputs is as follows. A input is sufficient if and only if the unit cost goes to zero when its price goes to zero.

  7. Perirhinal cortex lesions attenuate stimulus generalization in a tactual discrimination task in rats.

    Science.gov (United States)

    Ramos, Juan M J

    2014-01-01

    Response generalization to a novel stimulus occurs when the new stimulus shares common features with the stimulus used in the original learning. Given the many recent studies suggesting that the perirhinal cortex is critical for disambiguating stimuli that share representational/perceptual elements, we hypothesize that lesions sustained to this region would attenuate response generalization. In the first part of this experiment lesioned and control rats learned a feature-ambiguous tactual discrimination task until they had all reached the same level of performance. In this task animals were asked to discriminate among 3 tactual stimuli simultaneously exposed in 3 arms of a 4-arm plus-shaped maze. In the second part of this experiment, the same rats were given a generalization test 24 h after acquisition of the tactual discrimination. In the generalization test the original tactual stimulus associated with reward during the learning of the discrimination was replaced by a novel tactual stimulus while the other two remained the same. Of the 3 stimuli used in the generalization test, the novel stimulus had the highest degree of feature overlap with respect to the original target stimulus used during the learning of the discrimination. The generalization test took place over two consecutive days, with 8 trials each day. On the first day of generalization, the results indicated that the lesioned rats generalized significantly worse than the control rats during the first 4 trials, but not during the last 4 trials. On the second day of generalization, however, both groups performed the test perfectly. These findings suggest that, in addition to the well-known mnesic function in object processing, the perirhinal cortex may also be involved in perceptual functions.

  8. Reconstruction of neuronal input through modeling single-neuron dynamics and computations

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Qing; Wang, Jiang; Yu, Haitao; Deng, Bin, E-mail: dengbin@tju.edu.cn; Chan, Wai-lok [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

    2016-06-15

    Mathematical models provide a mathematical description of neuron activity, which can better understand and quantify neural computations and corresponding biophysical mechanisms evoked by stimulus. In this paper, based on the output spike train evoked by the acupuncture mechanical stimulus, we present two different levels of models to describe the input-output system to achieve the reconstruction of neuronal input. The reconstruction process is divided into two steps: First, considering the neuronal spiking event as a Gamma stochastic process. The scale parameter and the shape parameter of Gamma process are, respectively, defined as two spiking characteristics, which are estimated by a state-space method. Then, leaky integrate-and-fire (LIF) model is used to mimic the response system and the estimated spiking characteristics are transformed into two temporal input parameters of LIF model, through two conversion formulas. We test this reconstruction method by three different groups of simulation data. All three groups of estimates reconstruct input parameters with fairly high accuracy. We then use this reconstruction method to estimate the non-measurable acupuncture input parameters. Results show that under three different frequencies of acupuncture stimulus conditions, estimated input parameters have an obvious difference. The higher the frequency of the acupuncture stimulus is, the higher the accuracy of reconstruction is.

  9. The Effect of Stimulus Size on the Reliable Stimulus Range of Perimetry.

    Science.gov (United States)

    Gardiner, Stuart K; Demirel, Shaban; Goren, Deborah; Mansberger, Steven L; Swanson, William H

    2015-03-01

    Automated perimetry uses a 3.5 log unit (35dB) range of stimulus contrasts to assess function within the visual field. Using 'Size III' stimuli (0.43°), presenting stimuli within the highest 15dB of available contrast may not increase the response probability at locations damaged by glaucoma, due to retinal ganglion cell response saturation. This experiment examines the effect of instead using 'Size V' (1.72°) stimuli. Luminance increment thresholds for circular spot stimuli of each stimulus size were measured in 35 participants (mean deviation -20.9 to -3.4 dB, ages 52-87) using the method of constant stimuli, at four locations per participant. Frequency-of-seeing curves were fit at each size and location, with three free parameters: mean, standard deviation, and asymptotic maximum response probability. These were used to estimate the contrasts to which each participant would respond on 25% of presentations (c25). Using segmented orthogonal regression, the maximum observed response probabilities for size III stimuli began to decline at c25 = 25.2 dB (95% confidence interval 23.3-29.0 dB from bootstrap resampling). This decline started at similar contrast for the size V stimulus: c25 = 25.0dB (22.0-26.8 dB). Among locations at which the sensitivity was above these split-points for both stimulus sizes, c25 averaged 5.6 dB higher for size V than size III stimuli. The lower limit of the reliable stimulus range did not differ significantly between stimulus sizes. However, more locations remained within the reliable stimulus range when using the size V stimulus. Size V stimuli enable reliable clinical testing later into the glaucomatous disease process.

  10. Teori Stres: Stimulus, Respons, dan Transaksional

    OpenAIRE

    Nasib Tua Lumban Gaol

    2016-01-01

    Understanding the fundamental concept of stress is necessary due to it leads to comprehending deeply regarding what stress is. Principally, there models of stress confirm what stress is and how stress occurs on human. First, the stimulus model of stress is the treating environments that stimulate individual to perceive stress. Second, the response model of stress is a bodily reaction to the source of stress. Third, the transactional model of stress is the evaluation process to the sources of ...

  11. Comprehensible input and learning outcomes

    OpenAIRE

    Salazar Campillo, Patricia

    1996-01-01

    Segones Jornades de Foment de la Investigació de la FCHS (Any 1996-1997) In Krashen’s terms, optimal input has to be comprehensible to the learner if we want acquisition to take place. An overview of the literature on input indicates two ways of making input comprehensible: the first one is to premodify input before it is offered to the learner, (premodified input), and the second one is to negotiate the input through interaction (interactionally modified input). The aim of the...

  12. Stimulus and transducer effects on threshold.

    Science.gov (United States)

    Flamme, Gregory A; Geda, Kyle; McGregor, Kara D; Wyllys, Krista; Deiters, Kristy K; Murphy, William J; Stephenson, Mark R

    2015-02-01

    This study examined differences in thresholds obtained under Sennheiser HDA200 circumaural earphones using pure tone, equivalent rectangular noise bands, and 1/3 octave noise bands relative to thresholds obtained using Telephonics TDH-39P supra-aural earphones. Thresholds were obtained via each transducer and stimulus condition six times within a 10-day period. Forty-nine adults were selected from a prior study to represent low, moderate, and high threshold reliability. The results suggested that (1) only small adjustments were needed to reach equivalent TDH-39P thresholds, (2) pure-tone thresholds obtained with HDA200 circumaural earphones had reliability equal to or better than those obtained using TDH-39P earphones, (3) the reliability of noise-band thresholds improved with broader stimulus bandwidth and was either equal to or better than pure-tone thresholds, and (4) frequency-specificity declined with stimulus bandwidths greater than one equivalent rectangular band, which could complicate early detection of hearing changes that occur within a narrow frequency range. These data suggest that circumaural earphones such as the HDA200 headphones provide better reliability for audiometric testing as compared to the TDH-39P earphones. These data support the use of noise bands, preferably ERB noises, as stimuli for audiometric monitoring.

  13. Performance breakdown in optimal stimulus decoding.

    Science.gov (United States)

    Lubomir Kostal; Lansky, Petr; Pilarski, Stevan

    2015-06-01

    One of the primary goals of neuroscience is to understand how neurons encode and process information about their environment. The problem is often approached indirectly by examining the degree to which the neuronal response reflects the stimulus feature of interest. In this context, the methods of signal estimation and detection theory provide the theoretical limits on the decoding accuracy with which the stimulus can be identified. The Cramér-Rao lower bound on the decoding precision is widely used, since it can be evaluated easily once the mathematical model of the stimulus-response relationship is determined. However, little is known about the behavior of different decoding schemes with respect to the bound if the neuronal population size is limited. We show that under broad conditions the optimal decoding displays a threshold-like shift in performance in dependence on the population size. The onset of the threshold determines a critical range where a small increment in size, signal-to-noise ratio or observation time yields a dramatic gain in the decoding precision. We demonstrate the existence of such threshold regions in early auditory and olfactory information coding. We discuss the origin of the threshold effect and its impact on the design of effective coding approaches in terms of relevant population size.

  14. Impact of stimulus uncanniness on speeded response

    Directory of Open Access Journals (Sweden)

    Kohske eTakahashi

    2015-05-01

    Full Text Available In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat.

  15. Input or intimacy

    Directory of Open Access Journals (Sweden)

    Judit Navracsics

    2014-01-01

    Full Text Available According to the critical period hypothesis, the earlier the acquisition of a second language starts, the better. Owing to the plasticity of the brain, up until a certain age a second language can be acquired successfully according to this view. Early second language learners are commonly said to have an advantage over later ones especially in phonetic/phonological acquisition. Native-like pronunciation is said to be most likely to be achieved by young learners. However, there is evidence of accentfree speech in second languages learnt after puberty as well. Occasionally, on the other hand, a nonnative accent may appear even in early second (or third language acquisition. Cross-linguistic influences are natural in multilingual development, and we would expect the dominant language to have an impact on the weaker one(s. The dominant language is usually the one that provides the largest amount of input for the child. But is it always the amount that counts? Perhaps sometimes other factors, such as emotions, ome into play? In this paper, data obtained from an EnglishPersian-Hungarian trilingual pair of siblings (under age 4 and 3 respectively is analyzed, with a special focus on cross-linguistic influences at the phonetic/phonological levels. It will be shown that beyond the amount of input there are more important factors that trigger interference in multilingual development.

  16. Influence of stimulus size on revealing non-cardinal color mechanisms.

    Science.gov (United States)

    Gunther, Karen L; Downey, Colin O

    2016-10-01

    Multiple studies have shown that performance of subjects on a number of visual tasks is worse for non-cardinal than cardinal colors, especially in the red-green/luminance (RG/LUM) and tritan/luminance (TRIT/LUM) color planes. Inspired by neurophysiological evidence that suppressive surround input to receptive fields is particularly sensitive to luminance, we hypothesized that non-cardinal mechanisms in the RG/LUM and TRIT/LUM planes would be more sensitive to stimulus size than are isoluminant non-cardinal mechanisms. In Experiment 1 we tested 9-10 color-normal subjects in each of the three color planes (RG/TRIT, RG/LUM, and TRIT/LUM) on visual search at four bull's-eye dot sizes (0.5°/1°, 1°/2°, 2°/4°, and 3°/6° center/annulus dot diameter). This study yielded a significant main effect of dot size in each of the three color planes. In Experiment 2 we tested the same hypothesis using noise masking, at three stimulus sizes (3°, 6° and 9° diameter Gabors), again in all three color planes (5 subjects per color plane). This experiment yielded, in the RG/TRIT plane, a significant main effect of stimulus size; in the RG/LUM plane, significant evidence for non-cardinal mechanisms only for the 9° stimulus; but in the TRIT/LUM plane no evidence for non-cardinal mechanisms at any stimulus size. These results suggest that non-cardinal mechanisms, particularly in the RG/LUM color plane, are more sensitive to stimulus size than are non-cardinals in the RG/TRIT plane, supporting our hypothesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Predicting Attraction to the Novel Stimulus Person: Affect and Concern.

    Science.gov (United States)

    Kelley, Kathryn

    1982-01-01

    Predicted interpersonal attraction to the novel stimulus by assessing the affective properties of stimulus descriptions. One group responded to characterizations on scales of concern. In another group, positive feelings and high concern about the stimulus led to greatest attraction. Results illustrate the benefits of prediction of the liking…

  18. Modeling the short-run effect of fiscal stimuli on GDP : A new semi-closed input-output model

    NARCIS (Netherlands)

    Chen, Quanrun; Dietzenbacher, Erik; Los, Bart; Yang, Cuihong

    2016-01-01

    In this study, we propose a new semi-closed input-output model, which reconciles input-output analysis with modern consumption theories. It can simulate changes in household consumption behavior when exogenous stimulus policies lead to higher disposable income levels. It is useful for quantifying

  19. Dynamic afferent synapses to decision-making networks improve performance in tasks requiring stimulus associations and discriminations

    Science.gov (United States)

    Bourjaily, Mark A.

    2012-01-01

    Animals must often make opposing responses to similar complex stimuli. Multiple sensory inputs from such stimuli combine to produce stimulus-specific patterns of neural activity. It is the differences between these activity patterns, even when small, that provide the basis for any differences in behavioral response. In the present study, we investigate three tasks with differing degrees of overlap in the inputs, each with just two response possibilities. We simulate behavioral output via winner-takes-all activity in one of two pools of neurons forming a biologically based decision-making layer. The decision-making layer receives inputs either in a direct stimulus-dependent manner or via an intervening recurrent network of neurons that form the associative layer, whose activity helps distinguish the stimuli of each task. We show that synaptic facilitation of synapses to the decision-making layer improves performance in these tasks, robustly increasing accuracy and speed of responses across multiple configurations of network inputs. Conversely, we find that synaptic depression worsens performance. In a linearly nonseparable task with exclusive-or logic, the benefit of synaptic facilitation lies in its superlinear transmission: effective synaptic strength increases with presynaptic firing rate, which enhances the already present superlinearity of presynaptic firing rate as a function of stimulus-dependent input. In linearly separable single-stimulus discrimination tasks, we find that facilitating synapses are always beneficial because synaptic facilitation always enhances any differences between inputs. Thus we predict that for optimal decision-making accuracy and speed, synapses from sensory or associative areas to decision-making or premotor areas should be facilitating. PMID:22457467

  20. Acute hyperkalemia and failure of pacemaker stimulus.

    Science.gov (United States)

    N'Guetta, Roland; Mansencal, Nicolas; Digne, Franck; Dubourg, Olivier

    2011-07-01

    Acute hyperkalemia may induce well-known serious cardiac arrhythmia. However, ventricular aberration including concealed conduction may also occur. We report the case of a 35-year-old woman who had a previous history of late-operated ventricular septal defect communication and DDD pacemaker was admitted for dyspnea. During hospitalization, an acute hyperkalemia induced sinoatrial block despite correct pacemaker programming. Sodium bicarbonate allowed to restore sinus rhythm. Our report highlights that acute hyperkalemia may increase thresholds of pacemaker stimulus and physicians should be aware that complete block of conduction may occur despite correct pacemaker programming. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

  1. Multisensory temporal integration: task and stimulus dependencies.

    Science.gov (United States)

    Stevenson, Ryan A; Wallace, Mark T

    2013-06-01

    The ability of human sensory systems to integrate information across the different modalities provides a wide range of behavioral and perceptual benefits. This integration process is dependent upon the temporal relationship of the different sensory signals, with stimuli occurring close together in time typically resulting in the largest behavior changes. The range of temporal intervals over which such benefits are seen is typically referred to as the temporal binding window (TBW). Given the importance of temporal factors in multisensory integration under both normal and atypical circumstances such as autism and dyslexia, the TBW has been measured with a variety of experimental protocols that differ according to criterion, task, and stimulus type, making comparisons across experiments difficult. In the current study, we attempt to elucidate the role that these various factors play in the measurement of this important construct. The results show a strong effect of stimulus type, with the TBW assessed with speech stimuli being both larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes.

  2. Hospital Clowning as Play Stimulus in Healthcare

    Directory of Open Access Journals (Sweden)

    Laura Anes

    2014-10-01

    Full Text Available A serious illness, a chronic medical condition or a hospital bed should not deny any child her/his basic right to play, a right essential for children’s development and general wellbeing. In fact, it is in these frightening and anxious moments that play and the stimulus that it provides can help the most. This article will focus on the impacts and benefits of professional hospital clowning for the wellbeing and recovery process of ill and hospitalized children. Our experience has shown that through interactive play and humor, “clowndoctors” can create an enabling and supportive environment that facilitates children’s adaptation to the hospital setting and improves their acceptance of medical procedures and staff. While moving from bedside to bedside, RED NOSES clowndoctors encourage children’s active participation and support their natural instinct to play, fully including them in the interaction, if the children wish to do so. Therefore, clowndoctor performances offer ill children much needed stimulus, self-confidence and courage, elements fundamental to reducing their vulnerability. In this piece, a special emphasis will be put on the various approaches used by RED NOSES clowndoctors to bond and reach out to children suffering from different medical conditions.

  3. Control effects of stimulus paradigms on characteristic firings of parkinsonism

    Science.gov (United States)

    Zhang, Honghui; Wang, Qingyun; Chen, Guanrong

    2014-09-01

    Experimental studies have shown that neuron population located in the basal ganglia of parkinsonian primates can exhibit characteristic firings with certain firing rates differing from normal brain activities. Motivated by recent experimental findings, we investigate the effects of various stimulation paradigms on the firing rates of parkinsonism based on the proposed dynamical models. Our results show that the closed-loop deep brain stimulation is superior in ameliorating the firing behaviors of the parkinsonism, and other control strategies have similar effects according to the observation of electrophysiological experiments. In addition, in conformity to physiological experiments, we found that there exists optimal delay of input in the closed-loop GPtrain|M1 paradigm, where more normal behaviors can be obtained. More interestingly, we observed that W-shaped curves of the firing rates always appear as stimulus delay varies. We furthermore verify the robustness of the obtained results by studying three pallidal discharge rates of the parkinsonism based on the conductance-based model, as well as the integrate-and-fire-or-burst model. Finally, we show that short-term plasticity can improve the firing rates and optimize the control effects on parkinsonism. Our conclusions may give more theoretical insight into Parkinson's disease studies.

  4. Recent Visual Experience Shapes Visual Processing in Rats through Stimulus-Specific Adaptation and Response Enhancement.

    Science.gov (United States)

    Vinken, Kasper; Vogels, Rufin; Op de Beeck, Hans

    2017-03-20

    From an ecological point of view, it is generally suggested that the main goal of vision in rats and mice is navigation and (aerial) predator evasion [1-3]. The latter requires fast and accurate detection of a change in the visual environment. An outstanding question is whether there are mechanisms in the rodent visual system that would support and facilitate visual change detection. An experimental protocol frequently used to investigate change detection in humans is the oddball paradigm, in which a rare, unexpected stimulus is presented in a train of stimulus repetitions [4]. A popular "predictive coding" theory of cortical responses states that neural responses should decrease for expected sensory input and increase for unexpected input [5, 6]. Despite evidence for response suppression and enhancement in noninvasive scalp recordings in humans with this paradigm [7, 8], it has proven challenging to observe both phenomena in invasive action potential recordings in other animals [9-11]. During a visual oddball experiment, we recorded multi-unit spiking activity in rat primary visual cortex (V1) and latero-intermediate area (LI), which is a higher area of the rodent ventral visual stream. In rat V1, there was only evidence for response suppression related to stimulus-specific adaptation, and not for response enhancement. However, higher up in area LI, spiking activity showed clear surprise-based response enhancement in addition to stimulus-specific adaptation. These results show that neural responses along the rat ventral visual stream become increasingly sensitive to changes in the visual environment, suggesting a system specialized in the detection of unexpected events. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Serial Input Output

    Energy Technology Data Exchange (ETDEWEB)

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  6. SDR Input Power Estimation Algorithms

    Science.gov (United States)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  7. SDR input power estimation algorithms

    Science.gov (United States)

    Briones, J. C.; Nappier, J. M.

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  8. Inferring nonlinear neuronal computation based on physiologically plausible inputs.

    Directory of Open Access Journals (Sweden)

    James M McFarland

    Full Text Available The computation represented by a sensory neuron's response to stimuli is constructed from an array of physiological processes both belonging to that neuron and inherited from its inputs. Although many of these physiological processes are known to be nonlinear, linear approximations are commonly used to describe the stimulus selectivity of sensory neurons (i.e., linear receptive fields. Here we present an approach for modeling sensory processing, termed the Nonlinear Input Model (NIM, which is based on the hypothesis that the dominant nonlinearities imposed by physiological mechanisms arise from rectification of a neuron's inputs. Incorporating such 'upstream nonlinearities' within the standard linear-nonlinear (LN cascade modeling structure implicitly allows for the identification of multiple stimulus features driving a neuron's response, which become directly interpretable as either excitatory or inhibitory. Because its form is analogous to an integrate-and-fire neuron receiving excitatory and inhibitory inputs, model fitting can be guided by prior knowledge about the inputs to a given neuron, and elements of the resulting model can often result in specific physiological predictions. Furthermore, by providing an explicit probabilistic model with a relatively simple nonlinear structure, its parameters can be efficiently optimized and appropriately regularized. Parameter estimation is robust and efficient even with large numbers of model components and in the context of high-dimensional stimuli with complex statistical structure (e.g. natural stimuli. We describe detailed methods for estimating the model parameters, and illustrate the advantages of the NIM using a range of example sensory neurons in the visual and auditory systems. We thus present a modeling framework that can capture a broad range of nonlinear response functions while providing physiologically interpretable descriptions of neural computation.

  9. Lorazepam substitutes for the alcohol stimulus in social drinkers.

    Science.gov (United States)

    Jackson, Anne; Stephens, David N; Duka, Theodora

    2003-03-01

    The alcohol discriminative stimulus has been extensively studied in animals and demonstrated to be pharmacologically complex. In contrast, however, the alcohol stimulus has been less frequently studied in humans. The aim of the experiments reported here was to characterise pharmacologically an alcohol discriminative stimulus in social drinkers. Volunteers were first trained to discriminate a dose of 0.2 g/kg alcohol from placebo, using an established method. We then investigated the generalisation response and subjective effects following a range of doses of the gamma-amino-butyric acid (GABA)(A) benzodiazepine-receptor agonist lorazepam (0, 0.5, 1 and 2 mg, PO). Low doses of lorazepam (0.5 and 1 mg) did not cross-generalise with the alcohol stimulus and produced only minimal subjective effects. However, a dose of 2 mg lorazepam substituted (60.8%) for the stimulus ( Palcohol discriminative stimulus.

  10. Regional Hospital Input Price Indexes

    OpenAIRE

    Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

    1981-01-01

    This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associa...

  11. Varieties of Capitalism and Fiscal Stimulus, 2008–2010

    Directory of Open Access Journals (Sweden)

    Toloudis Nicholas

    2015-10-01

    Full Text Available This paper tests the Varieties of Capitalism (VoC framework to explain variation in fiscal stimulus measures across OECD countries in response to the 2008-2010 economic crisis. Following Soskice (2007, I argue that coordinated market economies are less flexible with fiscal policy than liberal market economies. Multivariate analysis across 23 OECD countries demonstrates that VoC is more powerful than three competing theories: fiscal institutions, which hypothesizes more stimulus in countries with less restrictive budgetary rules; debt credibility, which hypothesizes more stimulus in less indebted countries; and political partisanship, which hypothesizes more stimulus in countries governed by the left.

  12. The effects of stimulus symmetry on hierarchical processing in infancy.

    Science.gov (United States)

    Guy, Maggie W; Reynolds, Greg D; Mosteller, Sara M; Dixon, Kate C

    2017-04-01

    The current study investigated the effects of stimulus symmetry on the processing of global and local stimulus properties by 6-month-old short- and long-looking infants through the use of event-related potentials (ERPs). Previous research has shown that individual differences in infant visual attention are related to hierarchical stimulus processing, such that short lookers show a global processing bias, while long lookers demonstrate a local processing bias (Guy, Reynolds, & Zhang, 2013). Additional research has shown that in comparison with asymmetry, symmetry is associated with more efficient stimulus processing and more accurate memory for stimulus configuration (Attneave, 1955; Perkins, 1932). In the current study, we utilized symmetric and asymmetric hierarchical stimuli and predicted that the presence of asymmetry would direct infant attention to the local features of stimuli, leading short lookers to regress to a local processing strategy. Results of the ERP analysis showed that infants familiarized with a symmetric stimulus showed evidence of global processing, while infants familiarized with an asymmetric stimulus did not demonstrate evidence of processing at the global or local level. These findings indicate that short- and long-looking infants, who might otherwise fail to process global stimulus properties due to limited visual scanning, may succeed at global processing when exposed to symmetric stimuli. Furthermore, stimulus symmetry may recruit selective attention toward global properties of visual stimuli, facilitating higher-level cognitive processing in infancy. © 2017 Wiley Periodicals, Inc.

  13. Classical Conditioning Components of the Orienting Reflex to Words Using Innocuous and Noxious Unconditioned Stimuli Under Different Conditioned Stimulus-Unconditioned Stimulus Intervals

    Science.gov (United States)

    Maltzman, Irving; And Others

    1977-01-01

    Concerns the examination of conditioned stimulus--unconditioned stimulus (CS--UCS) intervals of different lengths. Demonstrates the feasibility of using a forewarned reaction time procedure with an innocuous imperative stimulus for the investigation of classical conditioning. (Editor/RK)

  14. Sustainable Food & Sustainable Economics

    OpenAIRE

    Alvarez, Mavis Dora

    2012-01-01

    Cuba today is immersed in a very intense process of perfecting its agricultural production structures with the goal of making them more efficient and sustainable in their economic administration and in their social and environmental management. Agricultural cooperatives in Cuba have the responsibility of producing on 73% of the country's farmland. Their contributions are decisive to developing agricultural production and to ensuring more and better food for the population, in addition to redu...

  15. Sustainability in organizations: advantages and challenges

    Directory of Open Access Journals (Sweden)

    Fábio Josende Paz

    2016-06-01

    Full Text Available Organizations are currently seeking to adopt sustainable policies and practices, causing a greater search for and use of sustainable models. This article therefore aims to evaluate the advantages of using sustainability principles in organizations, as well as to detect the main difficulties in implementing a sustainable model, identifying the existence of the principles described by Oliveira et al. (2012 and other authors. Bibliographic research was used to understand the “state of the art” in relation to sustainability in organizations, and the data was collected from articles published in journals in the last eight years. The importance of sustainability to organizations, better financial performance, stimulus for innovation, better management and the involvement of stakeholders in their processes were all evident as advantages of using this methodology. Finally, the following challenges were identified: the need for an investigation into the organization’s maturity in the use of sustainable methods and preparation of human resources for organizational change.

  16. The Influence of Mexican Hat Recurrent Connectivity on Noise Correlations and Stimulus Encoding

    Directory of Open Access Journals (Sweden)

    Robert Meyer

    2017-05-01

    Full Text Available Noise correlations are a common feature of neural responses and have been observed in many cortical areas across different species. These correlations can influence information processing by enhancing or diminishing the quality of the neural code, but the origin of these correlations is still a matter of controversy. In this computational study we explore the hypothesis that noise correlations are the result of local recurrent excitatory and inhibitory connections. We simulated two-dimensional networks of adaptive spiking neurons with local connection patterns following Gaussian kernels. Noise correlations decay with distance between neurons but are only observed if the range of excitatory connections is smaller than the range of inhibitory connections (“Mexican hat” connectivity and if the connection strengths are sufficiently strong. These correlations arise from a moving blob-like structure of evoked activity, which is absent if inhibitory interactions have a smaller range (“inverse Mexican hat” connectivity. Spatially structured external inputs fixate these blobs to certain locations and thus effectively reduce noise correlations. We further investigated the influence of these network configurations on stimulus encoding. On the one hand, the observed correlations diminish information about a stimulus encoded by a network. On the other hand, correlated activity allows for more precise encoding of stimulus information if the decoder has only access to a limited amount of neurons.

  17. The role of first- and second-order stimulus features for human overt attention.

    Science.gov (United States)

    Frey, Hans-Peter; König, Peter; Einhäuser, Wolfgang

    2007-02-01

    When processing complex visual input, human observers sequentially allocate their attention to different subsets of the stimulus. What are the mechanisms and strategies that guide this selection process? We investigated the influence of various stimulus features on human overt attention--that is, attention related to shifts of gaze with natural color images and modified versions thereof. Our experimental modifications, systematic changes of hue across the entire image, influenced only the global appearance of the stimuli, leaving the local features under investigation unaffected. We demonstrated that these modifications consistently reduce the subjective interpretation of a stimulus as "natural" across observers. By analyzing fixations, we found that first-order features, such as luminance contrast, saturation, and color contrast along either of the cardinal axes, correlated to overt attention in the modified images. In contrast, no such correlation was found in unmodified outdoor images. Second-order luminance contrast ("texture contrast") correlated to overt attention in all conditions. However, although none of the second-order color contrasts were correlated to overt attention in unmodified images, one of the second-order color contrasts did exhibit a significant correlation in the modified images. These findings imply, on the one hand, that higher-order bottom-up effects--namely, those of second-order luminance contrast--may partially account for human overt attention. On the other hand, these results also demonstrate that global image properties, which correlate to the subjective impression of a scene being "natural," affect the guidance of human overt attention.

  18. Emotion stimulus processing in narcolepsy with cataplexy.

    Science.gov (United States)

    Susta, Marek; Nemcova, Veronika; Bizik, Gustav; Sonka, Karel

    2017-02-01

    Reported brain abnormalities in anatomy and function in patients with narcolepsy with cataplexy led to a project based on qualitative electroencephalography examination and analysis in an attempt to find a narcolepsy with cataplexy-specific brain-derived pattern, or a sequence of brain locations involved in processing humorous stimuli. Laughter is the trigger of cataplexy in these patients, and the difference between patients and healthy controls during the laughter should therefore be notable. Twenty-six adult patients (14 male, 12 female) suffering from narcolepsy with cataplexy and 10 healthy controls (five male, five female) were examined. The experiment was performed using a 256-channel electroencephalogram and then processed using specialized software built according to the scientific research team's specifications. The software utilizes electroencephalographic data recorded during elevated emotional states in participants to calculate the sequence of brain areas involved in emotion processing using non-linear and linear algorithms. Results show significant differences in activation (pre-laughter) patterns between the patients with narcolepsy and healthy controls, as well as significant similarities within the patients and the controls. Specifically, gyrus orbitalis, rectus and occipitalis inferior are active in healthy controls, while gyrus paracentralis, cingularis and cuneus are activated solely in the patients in response to humorous audio stimulus. There are qualitative electroencephalographic-based patterns clearly discriminating between patients with narcolepsy and healthy controls during laughter processing. © 2016 European Sleep Research Society.

  19. P3a from a passive visual stimulus task.

    Science.gov (United States)

    Jeon, Y W; Polich, J

    2001-12-01

    Visual event-related brain potentials (ERPs) were elicited using a 3-stimulus oddball paradigm to assess the P3a with passive stimulus processing. Young adults (n=12) were presented with a series of visual stimuli consisting of a solid circle standard stimulus (P=0.76) that was difficult to discriminate from a larger target circle (P=0.12), with a large square distractor stimulus (P=0.12) presented randomly in the series. Subjects were instructed in the passive condition to simply look at the stimuli and in the active condition to press a mouse key only to the target stimulus. ERPs were recorded from 15 scalp electrodes, with the amplitude and latency of the P300 from the distractor and target stimuli assessed. The P3a from the distractor stimulus was similar in amplitude, scalp topography, and peak latency across the passive and active task conditions. The P3b from the target stimulus demonstrated much smaller amplitude, highly altered scalp topography, and longer latency for the passive compared to active task conditions. The P3a can be obtained with visual stimuli in the 3-stimulus paradigm under passive viewing conditions. Theoretical implications and clinical applications are discussed.

  20. A Computer Tutorial on the Principles of Stimulus Generalization.

    Science.gov (United States)

    Graham, Robert B.

    1998-01-01

    Describes a computer tutorial that teaches the fundamentals of stimulus generalization in operant learning. Concepts covered include reinforcement, discrimination learning, stimulus continua, generalization, generalization gradients, and peak shift. The tutorial also reviews applications in human and animal situations. The content is appropriate…

  1. Stimulus conflict predicts conflict adaptation in a numerical flanker task.

    Science.gov (United States)

    Notebaert, Wim; Verguts, Tom

    2006-12-01

    Conflict monitoring theory states that response conflict triggers conflict adaptation, resulting in reduced congruency effects after response-incongruent trials (Botvinick, Braver, Barch, Carter, & Cohen, 2001). Verbruggen, Notebaert, Liefooghe, and Vandierendonck (2006) observed conflict adaptation after stimulus-incongruent trials without any response conflict. In this study, we further explorethe hypothesis that stimulus conflict is an important trigger for conflict adaptation. We propose a measure for stimulus conflict that adequately explains the data of Verbruggen et al. and new data from a numerical flanker task. We conclude that stimulus conflict and response conflict have dissociable effects on behavior. Whereas response conflict is a good predictor of response times, stimulus conflict is a better predictor of the adaptation effect.

  2. Oscillatory Mechanisms of Stimulus Processing and Selection in the Visual and Auditory Systems: State-of-the-Art, Speculations and Suggestions

    Directory of Open Access Journals (Sweden)

    Benedikt Zoefel

    2017-05-01

    Full Text Available All sensory systems need to continuously prioritize and select incoming stimuli in order to avoid overflow or interference, and provide a structure to the brain's input. However, the characteristics of this input differ across sensory systems; therefore, and as a direct consequence, each sensory system might have developed specialized strategies to cope with the continuous stream of incoming information. Neural oscillations are intimately connected with this selection process, as they can be used by the brain to rhythmically amplify or attenuate input and therefore represent an optimal tool for stimulus selection. In this paper, we focus on oscillatory processes for stimulus selection in the visual and auditory systems. We point out both commonalities and differences between the two systems and develop several hypotheses, inspired by recently published findings: (1 The rhythmic component in its input is crucial for the auditory, but not for the visual system. The alignment between oscillatory phase and rhythmic input (phase entrainment is therefore an integral part of stimulus selection in the auditory system whereas the visual system merely adjusts its phase to upcoming events, without the need for any rhythmic component. (2 When input is unpredictable, the visual system can maintain its oscillatory sampling, whereas the auditory system switches to a different, potentially internally oriented, “mode” of processing that might be characterized by alpha oscillations. (3 Visual alpha can be divided into a faster occipital alpha (10 Hz and a slower frontal alpha (7 Hz that critically depends on attention.

  3. SIKAP MASYARAKAT DAN KONSERVASI KASUS STIMULUS PAKIS SAYUR DI DESA GUNUNG BUNDER II, KECAMATAN PAMIJAHAN, BOGOR

    Directory of Open Access Journals (Sweden)

    Zakiyyah Zakiyyah

    2016-05-01

    Full Text Available Vegetable ferns (Diplazium esculentum (Retz Sw which grows in the forest directly utilized by community and often does not take into account the survival. Utilization of vegetables ferns should be in line with its preservation is to do conservation actions that are based on sustainable development in line with the Regulation of Law No. 5 In 1990 , concerning the conservation of natural resources. To support the law, community’s attitudes must be constituted in accordance with the concept of "tri-stimulus amar proconservation" which consists of the natural, benefits, and willingly stimulus. This research aims to determine how the community’s attitude toward conservation of vegetable fern. Data taken from survey results with a questionnaire of attitudes processed with aid MSI (Methods of Successive Interval to see percentage numbers of community’s attitude. Based on the results of survey on 25 respondents, community’s attitudes indicate a positive attitude supporting the conservation vegetables fern but not entirely impact on the willingly stimulus. Community had no willingness to plant vegetable ferns because of the availability are abundant, does not have the land to grow and the lack of skills on how to plant vegetables ferns.

  4. Feedback control of electrically stimulated muscle using simultaneous pulse width and stimulus period modulation.

    Science.gov (United States)

    Chizeck, H J; Lan, N; Palmieri, L S; Crago, P E

    1991-12-01

    This paper considers the closed-loop control of electrically stimulated muscle using simultaneous pulse width and frequency modulation. Previous work has experimentally demonstrated good feedback regulation of muscle force using fixed parameter and an adaptive controller modulating pulse width. In this work, it is shown how the addition of pulse frequency modulation to pulse width modulation can improve controller performance. This combination controller has been developed for both single muscle activation and for costimulation of antagonists. This is accomplished using a single command input. In single muscle operation, the combination of pulse width and stimulus pulse frequency modulation results in better control of transient responses than with pulse width modulation alone; the total number of stimulus pulses is increased, however, when compared with pulse width-only modulation at the muscle fusion frequency. In the case of costimulation, the controller modulates the pulse stimulus periods of the antagonists in a reciprocal manner, to ensure stable and fast responses. That is, the frequency of stimulation of the antagonist is increased when that of the agonist is decreased. This results in better control performance with generally fewer stimulus pulses than those generated by costimulation using only pulse width modulation. This feedback controller was evaluated in animal experiments. Step responses with rapid rise times but without overshoot were obtained by the combined modulation. Good steady-state and transient performance were obtained over a wide range of static lengths and commands, under different loading conditions and in different animals. This controller is a promising potential component of neural prostheses to restore functional movement in paralyzed individuals.

  5. Volterra dendritic stimulus processors and biophysical spike generators with intrinsic noise sources.

    Science.gov (United States)

    Lazar, Aurel A; Zhou, Yiyin

    2014-01-01

    We consider a class of neural circuit models with internal noise sources arising in sensory systems. The basic neuron model in these circuits consists of a dendritic stimulus processor (DSP) cascaded with a biophysical spike generator (BSG). The dendritic stimulus processor is modeled as a set of nonlinear operators that are assumed to have a Volterra series representation. Biophysical point neuron models, such as the Hodgkin-Huxley neuron, are used to model the spike generator. We address the question of how intrinsic noise sources affect the precision in encoding and decoding of sensory stimuli and the functional identification of its sensory circuits. We investigate two intrinsic noise sources arising (i) in the active dendritic trees underlying the DSPs, and (ii) in the ion channels of the BSGs. Noise in dendritic stimulus processing arises from a combined effect of variability in synaptic transmission and dendritic interactions. Channel noise arises in the BSGs due to the fluctuation of the number of the active ion channels. Using a stochastic differential equations formalism we show that encoding with a neuron model consisting of a nonlinear DSP cascaded with a BSG with intrinsic noise sources can be treated as generalized sampling with noisy measurements. For single-input multi-output neural circuit models with feedforward, feedback and cross-feedback DSPs cascaded with BSGs we theoretically analyze the effect of noise sources on stimulus decoding. Building on a key duality property, the effect of noise parameters on the precision of the functional identification of the complete neural circuit with DSP/BSG neuron models is given. We demonstrate through extensive simulations the effects of noise on encoding stimuli with circuits that include neuron models that are akin to those commonly seen in sensory systems, e.g., complex cells in V1.

  6. Classification of stimuli based on stimulus-response curves and their variability.

    Science.gov (United States)

    Lansky, Petr; Pokora, Ondrej; Rospars, Jean-Pierre

    2008-08-15

    Neuronal responses evoked in sensory neurons by static stimuli of various intensities are usually characterized by their input-output transfer function, i.e. by plotting the firing frequency (or any other measurable neuron response) versus the corresponding stimulus intensity. The aim of the present article is to determine the stimulus intensities which can be considered as "the most important" from two different points of view: transferring as much information as possible and coding the intensity as precisely as possible. These two problems are very different because, for example, an informative signal may be difficult to identify. We show that the role of noise is crucial in both problems. To obtain the range of stimuli which are the best identified, we propose to use measures based on Fisher information as known from the theory of statistical inference. To classify the most important stimuli from the point of view of information transfer, we suggest methods based on information theory. We show that both the most identifiable signal and the most informative signal are not unique. To study this, a generic model of input-output transfer function is analyzed under the influence of several different types of noise. Finally, the methods are illustrated on a model and data pertaining to olfactory sensory neurons.

  7. Mass Media as a Remedy for Poverty of the Stimulus in the Foreign Language Context

    Directory of Open Access Journals (Sweden)

    Samaneh Tarighat

    2016-11-01

    Full Text Available The present study is intended to determine how extensive exposure to target language mass media can affect foreign language learning and the poverty of the stimulus problem in the foreign language context. For this purpose, an EFL learner was studied for the period of one month and was asked to have extensive exposure to English language mass media only. The case was also asked to record her experience in a journal on a daily basis. The results indicated tangible improvement in her English speaking, listening, pronunciation and vocabulary but hardly any improvement on her English writing. A more profound impact was reported on the subject’s four-year-old son who was not initially the focus of this study. The results suggest that considering the authentic, lengthy language input it provides, foreign language mass media can compensate for the problem of poverty of the stimulus in foreign language learning. It is concluded that formal language instruction and exposure to foreign language mass media outside the class can complement one another and promote foreign language learning on the whole. It is also evident that the impact of extensive language input varies with the age of the language learner, with young learners bearing more influence than adult learners as the effects of the critical period hypothesis.

  8. Resurgence: Response competition, stimulus control, and reinforcer control.

    Science.gov (United States)

    Podlesnik, Christopher A; Kelley, Michael E

    2014-09-01

    Resurgence is the relapse of a previously reinforced and then extinguished target response when extinguishing a more recently reinforced alternative response. We designed the present study to assess the contribution of stimulus-control and reinforcer-control processes in determining resurgence. In a modified resurgence procedure, we removed the alternative discriminative stimulus signaling alternative reinforcement when extinguishing the alternative response. This produced more abrupt resurgence of target responding than in a typical resurgence procedure maintaining the alternative discriminative stimulus when extinguishing the alternative response. The overall amount of resurgence did not differ. Importantly, a "renewal" control added and removed the alternative stimulus during extinction, identically as in the modified resurgence procedure. However, alternative responding was never reinforced, which produced no relapse of target responding. Therefore, the more abrupt resurgence with the modified procedure than with the typical procedure suggests removing the alternative stimulus reduced the competition between alternative and target responding. These findings revealed the importance of adding and removing alternative reinforcement in producing resurgence (reinforcer control) but little influence of simply adding and removing the alternative stimulus (stimulus control). These data suggest that clinicians should consider the long-term availability of the alternative response option when developing differential-reinforcement interventions. © Society for the Experimental Analysis of Behavior.

  9. Sound localization: effects of reverberation time, speaker array, stimulus frequency, and stimulus rise/decay.

    Science.gov (United States)

    Giguère, C; Abel, S M

    1993-08-01

    This research assessed the ability of human listeners to localize one-third octave noise bands in the horizontal plane. The effects of reverberation time (absorbent versus reverberant room), stimulus center frequency (500, 1000, 2000, and 4000 Hz), stimulus rise/decay time (5 vs 200 ms) and speaker array (frontal versus lateral) were investigated for four subjects using a forced-choice speaker-identification paradigm. Sound localization scores were consistently lower in the reverberant room than in the absorbent room. They also revealed strong frequency and azimuthal effects. The benefit of a shorter rise/decay time was small and limited to low frequencies. The identification of a speaker position depended strongly upon the array in which it was embedded, primarily because localization in the lateral array led to frequency-dependent front/back confusions and response bias. The results also illustrated the importance of choosing a coordinate system based on the auditory cone-of-confusion to analyze localization data for speaker arrays spanning the aural axis.

  10. Sustainable agriculture

    National Research Council Canada - National Science Library

    Lichtfouse, Eric

    2009-01-01

    ... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 Part I CLIMATE CHANGE Soils and Sustainable Agriculture: A Review : : : : : : : : : : : : : : : : : : : : : : : : : : Rattan Lal 15 Soils and Food Sufficiency...

  11. Sustainable Marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2017-01-01

    In this article, three different conceptions of sustainable marketing are discussed and compared. These different conceptions are referred to as social, green, and critical sustainable marketing. Social sustainable marketing follows the logic of demand-driven marketing management and places the

  12. Input-dependent wave attenuation in a critically-balanced model of cortex.

    Directory of Open Access Journals (Sweden)

    Xiao-Hu Yan

    Full Text Available A number of studies have suggested that many properties of brain activity can be understood in terms of critical systems. However it is still not known how the long-range susceptibilities characteristic of criticality arise in the living brain from its local connectivity structures. Here we prove that a dynamically critically-poised model of cortex acquires an infinitely-long ranged susceptibility in the absence of input. When an input is presented, the susceptibility attenuates exponentially as a function of distance, with an increasing spatial attenuation constant (i.e., decreasing range the larger the input. This is in direct agreement with recent results that show that waves of local field potential activity evoked by single spikes in primary visual cortex of cat and macaque attenuate with a characteristic length that also increases with decreasing contrast of the visual stimulus. A susceptibility that changes spatial range with input strength can be thought to implement an input-dependent spatial integration: when the input is large, no additional evidence is needed in addition to the local input; when the input is weak, evidence needs to be integrated over a larger spatial domain to achieve a decision. Such input-strength-dependent strategies have been demonstrated in visual processing. Our results suggest that input-strength dependent spatial integration may be a natural feature of a critically-balanced cortical network.

  13. Gamma oscillatory amplitude encodes stimulus intensity in primary somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Holly Elizabeth Rossiter

    2013-07-01

    Full Text Available Gamma oscillations have previously been linked to pain perception and it has been hypothesised that they may have a potential role in encoding pain intensity. Stimulus response experiments have reported an increase in activity in the primary somatosensory cortex (SI with increasing stimulus intensity, but the specific role of oscillatory dynamics in this change in activation remains unclear. In this study, Magnetoencephalography (MEG was used to investigate the changes in cortical oscillations during 4 different intensities of a train of electrical stimuli to the right index finger, ranging from low sensation to strong pain. In those participants showing changes in evoked oscillatory gamma in SI during stimulation, the strength of the gamma power was found to increase with increasing stimulus intensity at both pain and sub-pain thresholds. These results suggest that evoked gamma oscillations in SI are not specific to pain but may have a role in encoding somatosensory stimulus intensity.

  14. The rapid emergence of stimulus specific perceptual learning

    Directory of Open Access Journals (Sweden)

    Zahra eHussain

    2012-07-01

    Full Text Available Is stimulus specific perceptual learning the result of extended practice or does it emerge early in the time course of learning? We examined this issue by manipulating the amount of practice given on a face identification task on Day 1, and altering the familiarity of stimuli on Day 2. We found that a small number of trials was sufficient to produce stimulus specific perceptual learning of faces: on Day 2, response accuracy decreased by the same amount for novel stimuli regardless of whether observers practiced 105 or 840 trials on Day 1. Current models of learning assume early procedural improvements followed by late stimulus specific gains. Our results show that stimulus specific and procedural improvements are distributed throughout the time course of learning

  15. Promoting response variability and stimulus generalization in martial arts training

    National Research Council Canada - National Science Library

    Harding, Jay W; Wacker, David P; Berg, Wendy K; Rick, Gary; Lee, John F

    2004-01-01

    The effects of reinforcement and extinction on response variability and stimulus generalization in the punching and kicking techniques of 2 martial arts students were evaluated across drill and sparring conditions...

  16. Educational Implications of Stimulus Overselectivity in Autistic Children.

    Science.gov (United States)

    Dunlap, Glen; And Others

    1981-01-01

    Research is reviewed on stimulus overselectivity in autistic children, and educational implications are discussed in terms of language acquisition, social behavior, observational learning, generalization, and prompting and prompt fading. Approaches to circumvent the problem of overselectivity are also described. (CL)

  17. Auditory Stimulus Equivalence and Non-Arbitrary Relations

    National Research Council Canada - National Science Library

    Stewart, Ian; Lavelle, Niamh

    2013-01-01

    This study extended previous research on stimulus equivalence with all auditory stimuli by using a methodology more similar to conventional match-to-sample training and testing for three 3-member equivalence relations...

  18. The Stimulus Movement Effect: Allocation of Attention or Artifact?

    Science.gov (United States)

    Washburn, David A.

    1993-01-01

    In previous reports, including one by the author, learning has been shown to benefit by having discriminanda move rather than remain stationary. This stimulus movement effect might be attributed to several theoretical mechanisms, including attention, topological memory, and exposure duration. The series of experiments reported in this article was designed to Contrast these potential explanatory factors. Ten rhesus monkeys (Macaca mulatta) were tested on a variety of computerized tasks in which the stimuli remained stationary, flashed, or moved at systematically varied speeds. Performance was significantly best when the sample stimulus moved quickly and was poorest when the stimulus remained stationary. Further analysis of these data and other previously published data revealed that the distribution of the stimulus movement effect across trials supported an attention allocation interpretation.

  19. Learned helplessness as conditioned inattention to the target stimulus.

    Science.gov (United States)

    Barber, J G; Winefield, A H

    1986-09-01

    Learned helplessness theory explains the impaired performance that follows exposure to uncontrollable outcomes by assuming learned expectation of response-outcome independence that is transferred between tasks. Recent evidence has shown that introducing a second neutral stimulus, contingent on the offset of the uncontrollable stimulus, removes the subsequent interference. This finding has been claimed to support the view that the interference is a result of conditioned inattention rather than of the expectation of response-outcome independence. These conflicting explanations were examined in a series of four experiments that varied induction procedures (passive exposure or inescapability) and stimulus quality (aversive or nonaversive). All four experiments found the predicted interference, but only one, in which passive exposure was combined with an aversive stimulus, obtained results supporting the conditioned inattention hypothesis. We conclude that learned helplessness probably involves more than a single mechanism and that the passive exposure procedure may not be appropriate for demonstrating genuine helplessness deficits.

  20. Amygdala Contributions to Stimulus-Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning.

    Science.gov (United States)

    Rudebeck, Peter H; Ripple, Joshua A; Mitz, Andrew R; Averbeck, Bruno B; Murray, Elisabeth A

    2017-02-22

    Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus-reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus-reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus-reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus-reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus-reward associations. MFC also showed

  1. Thalamic neuron models encode stimulus information by burst-size modulation

    Directory of Open Access Journals (Sweden)

    Daniel Henry Elijah

    2015-09-01

    Full Text Available Thalamic neurons have been long assumed to fire in tonic mode during perceptive states, and in burst mode during sleep and unconsciousness. However, recent evidence suggests that bursts may also be relevant in the encoding of sensory information. Here we explore the neural code of such thalamic bursts. In order to assess whether the burst code is generic or whether it depends on the detailed properties of each bursting neuron, we analyzed two neuron models incorporating different levels of biological detail. One of the models contained no information of the biophysical processes entailed in spike generation, and described neuron activity at a phenomenological level. The second model represented the evolution of the individual ionic conductances involved in spiking and bursting, and required a large number of parameters. We analyzed the models' input selectivity using reverse correlation methods and information theory. We found that n-spike bursts from both models transmit information by modulating their spike count in response to changes to instantaneous input features, such as slope, phase, amplitude, etc. The stimulus feature that is most efficiently encoded by bursts, however, need not coincide with one of such classical features. We therefore searched for the optimal feature among all those that could be expressed as a linear transformation of the time-dependent input current. We found that bursting neurons transmitted 6 times more information about such more general features. The relevant events in the stimulus were located in a time window spanning ~100 ms before and ~20 ms after burst onset. Most importantly, the neural code employed by the simple and the biologically realistic models was largely the same, implying that the simple thalamic neuron model contains the essential ingredients that account for the computational properties of the thalamic burst code. Thus, our results suggest the n-spike burst code is a general property of

  2. Thalamic neuron models encode stimulus information by burst-size modulation.

    Science.gov (United States)

    Elijah, Daniel H; Samengo, Inés; Montemurro, Marcelo A

    2015-01-01

    Thalamic neurons have been long assumed to fire in tonic mode during perceptive states, and in burst mode during sleep and unconsciousness. However, recent evidence suggests that bursts may also be relevant in the encoding of sensory information. Here, we explore the neural code of such thalamic bursts. In order to assess whether the burst code is generic or whether it depends on the detailed properties of each bursting neuron, we analyzed two neuron models incorporating different levels of biological detail. One of the models contained no information of the biophysical processes entailed in spike generation, and described neuron activity at a phenomenological level. The second model represented the evolution of the individual ionic conductances involved in spiking and bursting, and required a large number of parameters. We analyzed the models' input selectivity using reverse correlation methods and information theory. We found that n-spike bursts from both models transmit information by modulating their spike count in response to changes to instantaneous input features, such as slope, phase, amplitude, etc. The stimulus feature that is most efficiently encoded by bursts, however, need not coincide with one of such classical features. We therefore searched for the optimal feature among all those that could be expressed as a linear transformation of the time-dependent input current. We found that bursting neurons transmitted 6 times more information about such more general features. The relevant events in the stimulus were located in a time window spanning ~100 ms before and ~20 ms after burst onset. Most importantly, the neural code employed by the simple and the biologically realistic models was largely the same, implying that the simple thalamic neuron model contains the essential ingredients that account for the computational properties of the thalamic burst code. Thus, our results suggest the n-spike burst code is a general property of thalamic neurons.

  3. The Impact of Stimulus Presentation and Size on Preference.

    Science.gov (United States)

    Moore, James W; Radley, Keith C; Dart, Evan H; Whipple, Heather M; Ness, Emily J; Murphy, Ashley N; Furlow, Chris; Wimberly, Joy K; Smith, Ashley

    2017-06-01

    The impact of stimulus size and presentation on choice during a preference assessment was investigated using a modified multiple-stimulus without replacement (MSWO) technique. Stimuli were either presented with a uniform magnitude, as determined by mass, or in a manner consistent with caregiver report of reinforcer consumption. While both assessment procedures identified the same top three preferred items in three out of five cases, greater variability in the preference rank of less preferred items was observed between assessments.

  4. Gamma oscillatory amplitude encodes stimulus intensity in primary somatosensory cortex

    OpenAIRE

    Holly Elizabeth Rossiter; Worthen, Sian F.; Caroline eWitton; Hall, Stephen D.; Furlong, Paul L

    2013-01-01

    Gamma oscillations have previously been linked to pain perception and it has been hypothesised that they may have a potential role in encoding pain intensity. Stimulus response experiments have reported an increase in activity in the primary somatosensory cortex (SI) with increasing stimulus intensity, but the specific role of oscillatory dynamics in this change in activation remains unclear. In this study, Magnetoencephalography (MEG) was used to investigate the changes in cortical oscillati...

  5. Psilocybin-induced stimulus control in the rat

    OpenAIRE

    Winter, J. C.; Rice, K. C.; Amorosi, D. J.; Rabin, R. A.

    2007-01-01

    Although psilocybin has been trained in the rat as a discriminative stimulus, little is known of the pharmacological receptors essential for stimulus control. In the present investigation rats were trained with psilocybin and tests were then conducted employing a series of other hallucinogens and presumed antagonists. An intermediate degree of antagonism of psilocybin was observed following treatment with the 5-HT2A receptor antagonist, M100907. In contrast, no significant antagonism was obse...

  6. P3a, perceptual distinctiveness, and stimulus modality.

    Science.gov (United States)

    Comerchero, M D; Polich, J

    1998-07-01

    A three-stimulus oddball paradigm (target, standard, nontarget) was employed in which subjects responded to an infrequent target, when its discrimination from the frequent standard was difficult. In separate auditory and visual modality conditions, the stimulus characteristics of an infrequent nontarget were manipulated such that its perceptual distinctiveness from the target was varied systematically. For both the low and high distinctiveness conditions, target stimulus P300 amplitude was larger than the nontarget only at the parietal electrode. In contrast, nontarget P3a amplitude was larger and earlier than the target P300 over the frontal/central electrode sites. The distinctiveness manipulation between the target and nontarget produced larger P3a component profiles for the auditory compared to visual stimuli. The results support previous findings that target/standard stimulus context determines P3a generation for both auditory and visual stimulus modalities and suggest that the distinctiveness of the eliciting stimulus contributes to P3a amplitude. Theoretical implications are discussed. Copyright 1998 Elsevier Science B.V.

  7. Effects of orientation and differential reinforcement on transitive stimulus control.

    Science.gov (United States)

    Amd, Micah; de Almeida, João H; de Rose, Júlio C; Silveira, Carolina C; Pompermaier, Henrique M

    2017-11-01

    The emergence of transitive relations between stimuli that had never appeared together is a key process underlying concept formation. An unresolved theoretical issue with respect to transitive relations has been to determine whether differential reinforcement of stimulus-stimulus (S-S) relations though matching-to-sample, or contiguous S-S correlations/pairings, is more critical for producing transitivity. The current study inquired whether simple environmental S-S pairings, versus differential reinforcement of S-S relations, versus environmental S-S pairings with an orientation requirement, produced the greatest instances of transitivity. 12 groups of participants were parsed into one of four procedures (matching-to-sample, stimulus-paring, stimulus-pairing-w/response, stimulus-pairing-w/orientation) along one of three training structures (linear, many-to-one, one-to-many). All participants underwent a fixed number of training trials for establishing three, three-member stimulus sets (A1B1C1, A2B2C2, A3B3C3), followed by a single sorting test for AC transitivity. Our results demonstrate orienting towards environmental S-S pairings yield the greatest degree of transitivity. The effectivity of pairing procedures for establishing transitive relations, particularly when compared to matching-to-sample, can inform the development of educational interventions for individuals for whom the latter procedure (involving differential reinforcement) is ineffective. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Transformation of stimulus correlations by the retina

    Science.gov (United States)

    Prentice, Jason; Simmons, Kristina; Tkacik, Gasper; Homann, Jan; Yee, Heather; Palmer, Stephanie; Nelson, Phillip; Balasubramanian, Vijay

    2014-03-01

    Correlations in the responses of sensory neurons seem to waste neural resources, but can carry cues about structured stimuli and help the brain correct for response errors. To assess how the retina negotiates this tradeoff, we measured simultaneous responses from many retinal ganglion cells presented with natural and artificial stimuli that varied in correlation structure. Responding to spatio-temporally structured stimuli such as natural movies, pairs of ganglion cells were more correlated than in response to white noise checkerboards, but were much less correlated than predicted by a non-adapting functional model of retinal response. Meanwhile, responding to stimuli with purely spatial correlations, pairs of ganglion cells showed increased correlations consistent with a static, non-adapting receptive field and nonlinearity. We found that in response to spatio- temporally correlated stimuli, ganglion cells had faster temporal kernels and tended to have stronger surrounds. These properties of individual cells, along with gain changes that opposed changes in effective contrast at the ganglion cell input, largely explained the pattern of correlations across stimuli.

  9. Discharges of Purkinje cells in monkey's flocculus during smooth-pursuit eye movements and visual stimulus movements.

    Science.gov (United States)

    Noda, H; Warabi, T

    1986-08-01

    Modulations in discharges of Purkinje cells (P cells) associated with movements of visual patterns were studied in the flocculus of monkeys trained to execute smooth-pursuit eye movements and to suppress optokinetic nystagmus. One class of P cells responded to the movements of visual stimulus regardless of whether the eyes remained stationary (produced retinal-slip velocity) or moved with the stimulus produced eye velocity). These P cells processed high-order information concerning the absolute velocity of stimulus movements and thereby the eye velocity had already been incorporated in the visual responses (visuomotor P cells). The other class of P cells responded to visual inputs resulting from the retinal slip (visual P cells). The majority of visual P cells (82%) also modulated their activities during smooth pursuit. When sinusoidal trackings were executed against a stationary visual background, various types of interactions occurred in the P-cell responses between the converging visual and oculomotor inputs. The type of interaction was related to the preferred direction for the P cell during eye movements and the side of the peripheral receptive field.

  10. Long-Term Synaptic Changes in Two Input Pathways into the Lateral Nucleus of the Amygdala Underlie Fear Extinction

    Science.gov (United States)

    Park, Junchol; Choi, June-Seek

    2010-01-01

    Plasticity in two input pathways into the lateral nucleus of the amygdala (LA), the medial prefrontal cortex (mPFC) and the sensory thalamus, have been suggested to underlie extinction, suppression of a previously acquired conditioned response (CR) following repeated presentations of the conditioned stimulus (CS). However, little is known about…

  11. Disentangling sequential effects of stimulus- and response-related conflict and stimulus-response repetition using brain potentials.

    Science.gov (United States)

    Wendt, Mike; Heldmann, Marcus; Münte, Thomas F; Kluwe, Rainer H

    2007-07-01

    Conflict monitoring theory holds that detection of conflicts in information processing by the anterior cingulate cortex (ACC) results in processing adaptation that minimizes subsequent conflict. Applying an Eriksen f lanker task with four stimuli mapped onto two responses, we investigated whether such modulation occurs only after response-related or also after stimulus-related conflict, focusing on the N2 component of the event-related potential. Contrasting with previous findings, both stimulus- and response-related conflict elicited enhancement of the N2, suggesting that the ACC is sensitive to conflict at both the stimulus and the response level. However, neither type of conflict resulted in reduced conflict effects on the following trial when stimulus-response (S-R) sequence effects were controlled by excluding identical S-R repetition trials. Identical S-R repetitions were associated with facilitated processing, thus demonstrating that inclusion of these trials in the analysis may mimic results predicted by the conflict adaptation hypothesis.

  12. World Input-Output Network.

    Directory of Open Access Journals (Sweden)

    Federica Cerina

    Full Text Available Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD is one of the first efforts to construct the global multi-regional input-output (GMRIO tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries.

  13. Analog Input Data Acquisition Software

    Science.gov (United States)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  14. Lab Inputs for Common Micros.

    Science.gov (United States)

    Tinker, Robert

    1984-01-01

    The game paddle inputs of Apple microcomputers provide a simple way to get laboratory measurements into the computer. Discusses these game paddles and the necessary interface software. Includes schematics for Apple built-in paddle electronics, TRS-80 game paddle I/O, Commodore circuit for user port, and bus interface for Sinclair/Timex, Commodore,…

  15. World Input-Output Network.

    Science.gov (United States)

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries.

  16. Remote input/output station

    CERN Multimedia

    1972-01-01

    A general view of the remote input/output station installed in building 112 (ISR) and used for submitting jobs to the CDC 6500 and 6600. The card reader on the left and the line printer on the right are operated by programmers on a self-service basis.

  17. Training methods for horses: habituation to a frightening stimulus.

    Science.gov (United States)

    Christensen, J W; Rundgren, M; Olsson, K

    2006-09-01

    Responses of horses in frightening situations are important for both equine and human safety. Considerable scientific interest has been shown in development of reactivity tests, but little effort has been dedicated to the development of appropriate training methods for reducing fearfulness. To investigate which of 3 different training methods (habituation, desensitisation and counter-conditioning) was most effective in teaching horses to react calmly in a potentially frightening situation. 1) Horses are able to generalise about the test stimulus such that, once familiar with the test stimulus in one situation, it appears less frightening and elicits a reduced response even when the stimulus intensity is increased or the stimulus is presented differently; and 2) alternative methods such as desensitisation and counter-conditioning would be more efficient than a classic habituation approach. Twenty-seven naive 2-year-old Danish Warmblood stallions were trained according to 3 different methods, based on classical learning theory: 1) horses (n = 9) were exposed to the full stimulus (a moving, white nylon bag, 1.2 x 0.75 m) in 5 daily training sessions until they met a predefined habituation criterion (habituation); 2) horses (n = 9) were introduced gradually to the stimulus and habituated to each step before the full stimulus was applied (desensitisation); 3) horses (n = 9) were trained to associate the stimulus with a positive reward before being exposed to the full stimulus (counter-conditioning). Each horse received 5 training sessions of 3 min per day. Heart rate and behavioural responses were recorded. Horses trained with the desensitisation method showed fewer flight responses in total and needed fewer training sessions to learn to react calmly to test stimuli. Variations in heart rate persisted even when behavioural responses had ceased. In addition, all horses on the desensitisation method eventually habituated to the test stimulus whereas some horses on the

  18. Sustainable Disruptions

    DEFF Research Database (Denmark)

    Friis, Silje Alberthe Kamille; Kjær, Lykke Bloch

    2016-01-01

    Since 2012 the Sustainable Disruptions (SD) project at the Laboratory for Sustainability at Design School Kolding (DK) has developed and tested a set of design thinking tools, specifically targeting the barriers to economically, socially, and environmentally sustainable business development....... The tools have been applied in practice in collaboration with 11 small and medium sized companies (SMEs). The study investigates these approaches to further understand how design thinking can contribute to sustainable transition in a business context. The study and the findings are relevant to organizations...... invested in the issue of sustainable business development, in particular the leaders and employees of SMEs, but also to design education seeking new ways to consciously handle and teach the complexity inherent in sustainable transformation. Findings indicate that the SD design thinking approach contributes...

  19. Global Aspects of Agricultural Sustainability

    Science.gov (United States)

    Edwards, Clive; Pimentel, David

    The following sections are included: * Introduction * Barriers to longterm sustainability * Loss of Land and Soils * Need for Adequate Water Resources * Energy Shortfalls * Potential Climate Change and Global Warming * Possible improvements in agricultural sustanability * Retardation of Soil Loss * Control of Water Supplies and Irrigation * New Sources of Renewable Energy * Biological Pest Control * Biological Inputs to Soil Fertility * Conclusions * References

  20. Computational sustainability

    CERN Document Server

    Kersting, Kristian; Morik, Katharina

    2016-01-01

    The book at hand gives an overview of the state of the art research in Computational Sustainability as well as case studies of different application scenarios. This covers topics such as renewable energy supply, energy storage and e-mobility, efficiency in data centers and networks, sustainable food and water supply, sustainable health, industrial production and quality, etc. The book describes computational methods and possible application scenarios.

  1. Interfacing sensory input with motor output: does the control architecture converge to a serial process along a single channel?

    Science.gov (United States)

    van de Kamp, Cornelis; Gawthrop, Peter J; Gollee, Henrik; Lakie, Martin; Loram, Ian D

    2013-01-01

    Modular organization in control architecture may underlie the versatility of human motor control; but the nature of the interface relating sensory input through task-selection in the space of performance variables to control actions in the space of the elemental variables is currently unknown. Our central question is whether the control architecture converges to a serial process along a single channel? In discrete reaction time experiments, psychologists have firmly associated a serial single channel hypothesis with refractoriness and response selection [psychological refractory period (PRP)]. Recently, we developed a methodology and evidence identifying refractoriness in sustained control of an external single degree-of-freedom system. We hypothesize that multi-segmental whole-body control also shows refractoriness. Eight participants controlled their whole body to ensure a head marker tracked a target as fast and accurately as possible. Analysis showed enhanced delays in response to stimuli with close temporal proximity to the preceding stimulus. Consistent with our preceding work, this evidence is incompatible with control as a linear time invariant process. This evidence is consistent with a single-channel serial ballistic process within the intermittent control paradigm with an intermittent interval of around 0.5 s. A control architecture reproducing intentional human movement control must reproduce refractoriness. Intermittent control is designed to provide computational time for an online optimization process and is appropriate for flexible adaptive control. For human motor control we suggest that parallel sensory input converges to a serial, single channel process involving planning, selection, and temporal inhibition of alternative responses prior to low dimensional motor output. Such design could aid robots to reproduce the flexibility of human control.

  2. Sustainable transformation

    DEFF Research Database (Denmark)

    Andersen, Nicolai Bo

    This paper is about sustainable transformation with a particular focus on listed buildings. It is based on the notion that sustainability is not just a question of energy conditions, but also about the building being robust. Robust architecture means that the building can be maintained and rebuilt...... theoretical lenses. It is proposed that three parameters concerning the ꞌtransformabilityꞌ of the building can contribute to a more nuanced understanding of sustainable transformation: technical aspects, programmatic requirements and narrative value. It is proposed that the concept of ꞌsustainable...

  3. Systems and methods for reconfiguring input devices

    Science.gov (United States)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  4. 78 FR 40689 - Solicitation of Input From Stakeholders Regarding the New Water Challenge Area Within the...

    Science.gov (United States)

    2013-07-08

    ... Food Production and Sustainability (IFPS), National Institute of Food and Agriculture, U.S. Department... the Food Security, Food Safety, Climate Variability and Change and Sustainable Bioenergy challenge... National Institute of Food and Agriculture Solicitation of Input From Stakeholders Regarding the New Water...

  5. Discriminative stimulus properties of mitragynine (kratom) in rats.

    Science.gov (United States)

    Harun, Norsyifa; Hassan, Zurina; Navaratnam, Visweswaran; Mansor, Sharif M; Shoaib, Mohammed

    2015-07-01

    Mitragynine (MG) is the primary active alkaloid extracted from the leaves of Mitragyna speciosa or kratom and exhibits pharmacological activities mediated by opioid receptors. The plant has been traditionally used for its opium and psychostimulant-like effects to increase work efficiency or as a substitute in the self-treatment of opiate addiction. The present study was performed to investigate the discriminative stimulus effects of MG in rats. The pharmacological mechanism of MG action and its derivative, 7-hydroxymitragynine (7-HMG) with a specific focus on opioid receptor involvement was examined in rats trained to discriminate morphine from vehicle. In order to study the dual actions of MG, the effect of cocaine substitution to the MG discriminative stimulus was also performed in MG-trained rats. Male Sprague Dawley rats were trained to discriminate MG from vehicle in a two-lever drug discrimination procedure under a tandem variable-interval (VI 60') fixed-ratio (FR 10) schedule of food reinforcement. Rats acquired the MG discrimination (15.0 mg/kg, i.p.) which was similar to the acquisition of morphine discrimination (5.0 mg/kg, i.p.) in another group of rats. MG substituted fully to the morphine discriminative stimulus in a dose-dependent manner, suggesting pharmacological similarities between the two drugs. The administration of 7-HMG derivative in 3.0 mg/kg (i.p.) dose engendered full generalisation to the morphine discriminative stimulus. In addition, the MG stimulus also partially generalised to cocaine (10.0 mg/kg, i.p.) stimulus. The present study demonstrates that the discriminative stimulus effect of MG possesses both opioid- and psychostimulant-like subjective effects.

  6. Dynamic dendritic compartmentalization underlies stimulus-specific adaptation in an insect neuron.

    Science.gov (United States)

    Prešern, Janez; Triblehorn, Jeffrey D; Schul, Johannes

    2015-06-01

    In many neural systems, repeated stimulation leads to stimulus-specific adaptation (SSA), with responses to repeated signals being reduced while responses to novel stimuli remain unaffected. The underlying mechanisms of SSA remain mostly hypothetical. One hypothesis is that dendritic processes generate SSA. Evidence for such a mechanism was recently described in an insect auditory interneuron (TN-1 in Neoconocephalus triops). Afferents, tuned to different frequencies, connect with different parts of the TN-1 dendrite. The specific adaptation of these inputs relies on calcium and sodium accumulation within the dendrite, with calcium having a transient and sodium a tonic effect. Using imaging techniques, we tested here whether the accumulation of these ions remained limited to the stimulated parts of the dendrite. Stimulation with a fast pulse rate, which results in strong adaptation, elicited a transient dendritic calcium signal. In contrast, the sodium signal was tonic, remaining high during the fast pulse rate stimulus. These time courses followed the predictions from the previous pharmacological experiments. The peak positions of the calcium and sodium signals differed with the carrier frequency of the stimulus; at 15 kHz, peak locations were significantly more rostral than at 40 kHz. This matched the predictions made from neuroanatomical data. Our findings confirm that excitatory postsynaptic potentials rather than spiking cause the increase of dendritic calcium and sodium concentrations and that these increases remain limited to the stimulated parts of the dendrite. This supports the hypothesis of "dynamic dendritic compartmentalization" underlying SSA in this auditory interneuron. Copyright © 2015 the American Physiological Society.

  7. Volterra dendritic stimulus processors and biophysical spike generators with intrinsic noise sources

    Directory of Open Access Journals (Sweden)

    Aurel A Lazar

    2014-09-01

    Full Text Available We consider a class of neural circuit models with internal noise sources arising in sensory systems. The basic neuron model in these circuits consists of a nonlinear dendritic stimulus processor (DSP cascaded with a biophysical spike generator (BSG. The nonlinear dendritic processor is modeled as a set of nonlinear operators that are assumed to have a Volterra series representation. Biophysical point neuron models, such as the Hodgkin-Huxley neuron, are used to model the spike generator. We address the question of how intrinsic noise sources affect the precision in encoding and decoding of sensory stimuli and the functional identification of its sensory circuits.We investigate two intrinsic noise sources arising (i in the active dendritic trees underlying the DSPs, and (ii in the ion channels of the BSGs. Noise in dendritic stimulus processing arises from a combined effect of variability in synaptic transmission and dendritic interactions. Channel noise arises in the BSGs due to the fluctuation of the number of the active ion channels. Using a stochastic differential equations formalism we show that encoding with a neuron model consisting of a nonlinear DSP cascaded with a BSG with intrinsic noise sources can be treated as generalized sampling with noisy measurements.For single-input multi-output neural circuit models with feedforward, feedback and cross-feedback DSPs cascaded with BSGs we theoretically analyze the effect of noise sources on stimulus decoding. Building on a key duality property, the effect of noise parameters on the precision of the functional identification of the complete neural circuit with DSP/BSG neuron models is given. We demonstrate through extensive simulations the effects of noise on encoding stimuli with circuits that include neuron models that are akin to those commonly seen in sensory systems, e.g., complex cells in V1.

  8. Nonassociative learning as gated neural integrator and differentiator in stimulus-response pathways

    Directory of Open Access Journals (Sweden)

    Young Daniel L

    2006-08-01

    Full Text Available Abstract Nonassociative learning is a basic neuroadaptive behavior exhibited across animal phyla and sensory modalities but its role in brain intelligence is unclear. Current literature on habituation and sensitization, the classic "dual process" of nonassociative learning, gives highly incongruous accounts between varying experimental paradigms. Here we propose a general theory of nonassociative learning featuring four base modes: habituation/primary sensitization in primary stimulus-response pathways, and desensitization/secondary sensitization in secondary stimulus-response pathways. Primary and secondary modes of nonassociative learning are distinguished by corresponding activity-dependent recall, or nonassociative gating, of neurotransmission memory. From the perspective of brain computation, nonassociative learning is a form of integral-differential calculus whereas nonassociative gating is a form of Boolean logic operator – both dynamically transforming the stimulus-response relationship. From the perspective of sensory integration, nonassociative gating provides temporal filtering whereas nonassociative learning affords low-pass, high-pass or band-pass/band-stop frequency filtering – effectively creating an intelligent sensory firewall that screens all stimuli for attention and resultant internal model adaptation and reaction. This unified framework ties together many salient characteristics of nonassociative learning and nonassociative gating and suggests a common kernel that correlates with a wide variety of sensorimotor integration behaviors such as central resetting and self-organization of sensory inputs, fail-safe sensorimotor compensation, integral-differential and gated modulation of sensorimotor feedbacks, alarm reaction, novelty detection and selective attention, as well as a variety of mental and neurological disorders such as sensorimotor instability, attention deficit hyperactivity, sensory defensiveness, autism

  9. Nonassociative learning as gated neural integrator and differentiator in stimulus-response pathways.

    Science.gov (United States)

    Poon, Chi-Sang; Young, Daniel L

    2006-08-08

    Nonassociative learning is a basic neuroadaptive behavior exhibited across animal phyla and sensory modalities but its role in brain intelligence is unclear. Current literature on habituation and sensitization, the classic "dual process" of nonassociative learning, gives highly incongruous accounts between varying experimental paradigms. Here we propose a general theory of nonassociative learning featuring four base modes: habituation/primary sensitization in primary stimulus-response pathways, and desensitization/secondary sensitization in secondary stimulus-response pathways. Primary and secondary modes of nonassociative learning are distinguished by corresponding activity-dependent recall, or nonassociative gating, of neurotransmission memory. From the perspective of brain computation, nonassociative learning is a form of integral-differential calculus whereas nonassociative gating is a form of Boolean logic operator--both dynamically transforming the stimulus-response relationship. From the perspective of sensory integration, nonassociative gating provides temporal filtering whereas nonassociative learning affords low-pass, high-pass or band-pass/band-stop frequency filtering--effectively creating an intelligent sensory firewall that screens all stimuli for attention and resultant internal model adaptation and reaction. This unified framework ties together many salient characteristics of nonassociative learning and nonassociative gating and suggests a common kernel that correlates with a wide variety of sensorimotor integration behaviors such as central resetting and self-organization of sensory inputs, fail-safe sensorimotor compensation, integral-differential and gated modulation of sensorimotor feedbacks, alarm reaction, novelty detection and selective attention, as well as a variety of mental and neurological disorders such as sensorimotor instability, attention deficit hyperactivity, sensory defensiveness, autism, nonassociative fear and anxiety

  10. The iso-response method: Measuring neuronal stimulus integration with closed-loop experiments

    Directory of Open Access Journals (Sweden)

    Tim eGollisch

    2012-12-01

    Full Text Available Throughout the nervous system, neurons integrate high-dimensional input streams and transform them into an output of their own. This integration of incoming signals involves filtering processes and complex nonlinear operations. The shapes of these filters and nonlinearities determine the computational features of single neurons and their functional roles within larger networks. A detailed characterization of signal integration is thus a central ingredient to understanding information processing in neural circuits. Conventional methods for measuring single-neuron response properties, such as reverse correlation, however, are often limited by the implicit assumption that stimulus integration occurs in a linear fashion. Here, we review a conceptual and experimental alternative that is based on exploring the space of those sensory stimuli that result in the same neural output. As demonstrated by recent results in the auditory and visual system, such iso-response stimuli can be used to identify the nonlinearities relevant for stimulus integration, disentangle subsequent neural processing steps, and determine their characteristics with unprecedented precision. Automated closed-loop experiments are crucial for this advance, allowing rapid search strategies for identifying iso-response stimuli during experiments. Prime targets for the method are feed-forward neural signaling chains in sensory systems, but the method has also been successfully applied to feedback systems. Depending on the specific question, iso-response may refer to a predefined firing rate, single-spike probability, first-spike latency, or other output measures. Examples from different studies show that substantial progress in understanding neural dynamics and coding can be achieved once rapid online data analysis and stimulus generation, adaptive sampling, and computational modelling are tightly integrated into experiments.

  11. The iso-response method: measuring neuronal stimulus integration with closed-loop experiments

    Science.gov (United States)

    Gollisch, Tim; Herz, Andreas V. M.

    2012-01-01

    Throughout the nervous system, neurons integrate high-dimensional input streams and transform them into an output of their own. This integration of incoming signals involves filtering processes and complex non-linear operations. The shapes of these filters and non-linearities determine the computational features of single neurons and their functional roles within larger networks. A detailed characterization of signal integration is thus a central ingredient to understanding information processing in neural circuits. Conventional methods for measuring single-neuron response properties, such as reverse correlation, however, are often limited by the implicit assumption that stimulus integration occurs in a linear fashion. Here, we review a conceptual and experimental alternative that is based on exploring the space of those sensory stimuli that result in the same neural output. As demonstrated by recent results in the auditory and visual system, such iso-response stimuli can be used to identify the non-linearities relevant for stimulus integration, disentangle consecutive neural processing steps, and determine their characteristics with unprecedented precision. Automated closed-loop experiments are crucial for this advance, allowing rapid search strategies for identifying iso-response stimuli during experiments. Prime targets for the method are feed-forward neural signaling chains in sensory systems, but the method has also been successfully applied to feedback systems. Depending on the specific question, “iso-response” may refer to a predefined firing rate, single-spike probability, first-spike latency, or other output measures. Examples from different studies show that substantial progress in understanding neural dynamics and coding can be achieved once rapid online data analysis and stimulus generation, adaptive sampling, and computational modeling are tightly integrated into experiments. PMID:23267315

  12. Stimulus and response chunking in the Hebb Digits task.

    Science.gov (United States)

    O'Shea, Geoffrey; Clegg, Benjamin A

    2006-05-01

    Using the Hebb Digits task, an incidental sequential learning paradigm, the effects of chunking of both the presentation and response phases of performance were examined. In the first experiment, consistent stimulus chunking increased learning, and performance was at an equivalent level to this when consistent chunking of both stimuli and responses was present. Consistent chunking of the responses alone did not significantly improve learning over a baseline condition where neither stimuli nor responses were chunked. The disruption of response organization in a second experiment, through a random response condition, failed to impact learning in non-chunked and stimulus chunked conditions. A third experiment found that response chunking did benefit learning in a condition where stimuli were presented in random chunks. A final experiment suggested extended processing of the digits could not account for performance gains in the stimulus chunking condition. Overall, the results suggest that the enhanced effects of chunking on learning were stimulus-driven rather than response-driven, except under conditions that constrained a consistent pattern of stimulus organization.

  13. Sustainable Transportation

    DEFF Research Database (Denmark)

    Hall, Ralph P.; Gudmundsson, Henrik; Marsden, Greg

    2014-01-01

    that relate to the construction and maintenance of transportation infrastructure and the operation or use of the different transportation modes. The concept of sustainable transportation emerged in response to these concerns as part of the broader notion of sustainable development. Given the transportation...

  14. Sustaining dairy

    NARCIS (Netherlands)

    Villarreal Herrera, Georgina

    2017-01-01

    Dairy in Europe has undergone many changes in the last few years—the abolition of milk production quotas being a fundamental one. This study explores these changes in relation to the sustained social and environmental viability of the sector and how dairy processors' sustainability

  15. Sustainable Universities

    DEFF Research Database (Denmark)

    Grindsted, Thomas Skou

    2011-01-01

    . Declarations tend to have impact on three trends. Firstly, there is emerging international consensus on the university’s role and function in relation to sustainable development; secondly, the emergence of national legislation, and thirdly, an emerging international competition to be leader in sustainable...... campus performance....

  16. Sustainable Transition

    DEFF Research Database (Denmark)

    Hansen, Ole Erik; Søndergård, Bent

    2014-01-01

    of agendas/vision, technologies, actors and institutions in the emergent design of an urban mobility system based on an electric car sharing system. Why. Designing for sustainability is a fundamental challenge for future design practices; designers have to obtain an ability to contribute to sustainable...

  17. Sustainable Learning

    Science.gov (United States)

    Cadwell, Louise; Dillon, Robert

    2011-01-01

    Green schools have moved into a new era that focuses on building a culture of sustainability in every aspect of learning in schools. In the early stages of sustainability education, the focus was on recycling and turning off the lights. Now, students and adults together are moving into the areas of advocacy and action that are based on a deep…

  18. The proportion of common synaptic input to motor neurons increases with an increase in net excitatory input.

    Science.gov (United States)

    Castronovo, Anna Margherita; Negro, Francesco; Conforto, Silvia; Farina, Dario

    2015-12-01

    α-Motor neurons receive synaptic inputs from spinal and supraspinal centers that comprise components either common to the motor neuron pool or independent. The input shared by motor neurons--common input--determines force control. The aim of the study was to investigate the changes in the strength of common synaptic input delivered to motor neurons with changes in force and with fatigue, two conditions that underlie an increase in the net excitatory drive to the motor neurons. High-density surface electromyogram (EMG) signals were recorded from the tibialis anterior muscle during contractions at 20, 50, and 75% of the maximal voluntary contraction force (in 3 sessions separated by at least 2 days), all sustained until task failure. EMG signal decomposition identified the activity of a total of 1,245 motor units. The coherence values between cumulative motor unit spike trains increased with increasing force, especially for low frequencies. This increase in coherence was not observed when comparing two subsets of motor units having different recruitment thresholds, but detected at the same force level. Moreover, the coherence values for frequencies input to motor neurons increases with respect to independent input when the net excitatory drive to motor neurons increases as a consequence of a change in force and fatigue. Copyright © 2015 the American Physiological Society.

  19. Internal Grammar and Children's Grammatical Creativity against Poor Inputs.

    Science.gov (United States)

    Belletti, Adriana

    2017-01-01

    This article is about the unexpected linguistic behavior that young children sometimes display by producing structures that are only marginally present in the adult language in a constrained way, and that adults do not adopt in the same experimental conditions. It is argued here that children's capacity to overextend the use of given syntactic structures thereby resulting in a grammatical creative behavior is the sign of an internal grammatical pressure which manifests itself given appropriate discourse conditions and factors of grammatical complexity and which does not necessarily require a rich input to be put into work. This poverty of the stimulus type situation is illustrated here through the overextended use of a -Topics and reflexive-causative passives by young Italian speaking children when answering eliciting questions concerning the direct object of the clause.

  20. Internal Grammar and Children's Grammatical Creativity against Poor Inputs

    Directory of Open Access Journals (Sweden)

    Adriana Belletti

    2017-12-01

    Full Text Available This article is about the unexpected linguistic behavior that young children sometimes display by producing structures that are only marginally present in the adult language in a constrained way, and that adults do not adopt in the same experimental conditions. It is argued here that children's capacity to overextend the use of given syntactic structures thereby resulting in a grammatical creative behavior is the sign of an internal grammatical pressure which manifests itself given appropriate discourse conditions and factors of grammatical complexity and which does not necessarily require a rich input to be put into work. This poverty of the stimulus type situation is illustrated here through the overextended use of a-Topics and reflexive-causative passives by young Italian speaking children when answering eliciting questions concerning the direct object of the clause.

  1. How northern freshwater input can stabilise thermohaline circulation

    Directory of Open Access Journals (Sweden)

    Erwin Lambert

    2016-11-01

    Full Text Available The North Atlantic thermohaline circulation (THC carries heat and salt towards the Arctic. This circulation is partly sustained by buoyancy loss and is generally believed to be inhibited by northern freshwater input as indicated by the ‘box-model’ of Stommel (1961. The inferred freshwater-sensitivity of the THC, however, varies considerably between studies, both quantitatively and qualitatively. The northernmost branch of the Atlantic THC, which forms a double estuarine circulation in the Arctic Mediterranean, is one example where both buoyancy loss and buoyancy gain facilitate circulation. We have built on Stommel's original concept to examine the freshwater-sensitivity of a double estuarine circulation. The net inflow into the double estuary is found to be more sensitive to a change in the distribution of freshwater than to a change in the total freshwater input. A double estuarine circulation is more stable than a single overturning, requiring a larger amount and more localised freshwater input into regions of buoyancy loss to induce a thermohaline ‘collapse’. For the Arctic Mediterranean, these findings imply that the Atlantic inflow may be relatively insensitive to increased freshwater input. Complementing Stommel's thermal and haline flow regimes, the double estuarine circulation allows for a third: the throughflow regime. In this regime, a THC with warm poleward surface flow can be sustained without production of dense water; a decrease in high-latitude dense water formation does therefore not necessarily affect regional surface conditions as strongly as generally thought.

  2. Executive control of stimulus-driven and goal-directed attention in visual working memory.

    Science.gov (United States)

    Hu, Yanmei; Allen, Richard J; Baddeley, Alan D; Hitch, Graham J

    2016-10-01

    We examined the role of executive control in stimulus-driven and goal-directed attention in visual working memory using probed recall of a series of objects, a task that allows study of the dynamics of storage through analysis of serial position data. Experiment 1 examined whether executive control underlies goal-directed prioritization of certain items within the sequence. Instructing participants to prioritize either the first or final item resulted in improved recall for these items, and an increase in concurrent task difficulty reduced or abolished these gains, consistent with their dependence on executive control. Experiment 2 examined whether executive control is also involved in the disruption caused by a post-series visual distractor (suffix). A demanding concurrent task disrupted memory for all items except the most recent, whereas a suffix disrupted only the most recent items. There was no interaction when concurrent load and suffix were combined, suggesting that deploying selective attention to ignore the distractor did not draw upon executive resources. A final experiment replicated the independent interfering effects of suffix and concurrent load while ruling out possible artifacts. We discuss the results in terms of a domain-general episodic buffer in which information is retained in a transient, limited capacity privileged state, influenced by both stimulus-driven and goal-directed processes. The privileged state contains the most recent environmental input together with goal-relevant representations being actively maintained using executive resources.

  3. The Effect of Stimulus Variability on Learning and Generalization of Reading in a Novel Script.

    Science.gov (United States)

    Adwan-Mansour, Jasmeen; Bitan, Tali

    2017-10-17

    The benefit of stimulus variability for generalization of acquired skills and knowledge has been shown in motor, perceptual, and language learning but has rarely been studied in reading. We studied the effect of variable training in a novel language on reading trained and untrained words. Sixty typical adults received 2 sessions of training in reading an artificial script. Participants were assigned to 1 of 3 groups: a variable training group practicing a large set of 24 words, and 2 nonvariable training groups practicing a smaller set of 12 words, with twice the number of repetitions per word. Variable training resulted in higher accuracy for both trained and untrained items composed of the same graphemes, compared to the nonvariable training. Moreover, performance on untrained items was correlated with phonemic awareness only for the nonvariable training groups. High stimulus variability increases the reliance on small unit decoding in adults reading in a novel script, which is beneficial for both familiar and novel words. These results show that the statistical properties of the input during reading acquisition influence the type of acquired knowledge and have theoretical and practical implications for planning efficient reading instruction methods. https://doi.org/10.23641/asha.5302195.

  4. Performance- and stimulus-dependent oscillations in monkey prefrontal cortex during short-term memory

    Directory of Open Access Journals (Sweden)

    Gordon Pipa

    2009-10-01

    Full Text Available Short-term memory requires the coordination of sub-processes like encoding, retention, retrieval and comparison of stored material to subsequent input. Neuronal oscillations have an inherent time structure, can effectively coordinate synaptic integration of large neuron populations and could therefore organize and integrate distributed sub-processes in time and space. We observed field potential oscillations (14-95Hz in ventral prefrontal cortex of monkeys performing a visual memory task. Stimulus-selective and performance-dependent oscillations occurred simultaneously at 65-95Hz and 14-50Hz, the latter being phase-locked throughout memory maintenance. We propose that prefrontal oscillatory activity may be instrumental for the dynamical integration of local and global neuronal processes underlying short-term memory.

  5. Implicit sequence learning is represented by stimulus-response rules.

    Science.gov (United States)

    Schwarb, Hillary; Schumacher, Eric H

    2010-09-01

    For nearly two decades, researchers have investigated spatial sequence learning in an attempt to identify what specifically is learned during sequential tasks (e.g., stimulus order, response order, etc.). Despite extensive research, controversy remains concerning the information-processing locus of this learning effect. There are three main theories concerning the nature of spatial sequence learning, corresponding to the perceptual, motor, or response selection (i.e., central mechanisms underlying the association between stimulus and response pairs) processes required for successful task performance. The present data investigate this controversy and support the theory that stimulus-response (S-R) rules are critical for sequence learning. The results from two experiments demonstrate that sequence learning is disrupted only when the S-R rules for the task are altered. When the S-R rules remain constant or involve only a minor transformation, significant sequence learning occurs. These data implicate spatial response selection as a likely mechanism mediating spatial sequential learning.

  6. Cognitive versus stimulus-response theories of learning.

    Science.gov (United States)

    Holland, Peter C

    2008-08-01

    In his 1948 address to the Division of Theoretical-Experimental Psychology of the American Psychological Association, Kenneth W. Spence discussed six distinctions between cognitive and stimulus-response (S-R) theories of learning. In this article, I first review these six distinctions and then focus on two of them in the context of my own research. This research concerns the specification of stimulus-stimulus associations in associative learning and the characterization of the neural systems underlying those associations. In the course of describing Spence's views and my research, I hope to communicate some of the richness of Spence's S-R psychology and its currency within modern scientific analyses of behavior.

  7. Stimulus-dependent effects on tactile spatial acuity

    Directory of Open Access Journals (Sweden)

    Tommerdahl M

    2005-10-01

    Full Text Available Abstract Background Previous studies have shown that spatio-tactile acuity is influenced by the clarity of the cortical response in primary somatosensory cortex (SI. Stimulus characteristics such as frequency, amplitude, and location of tactile stimuli presented to the skin have been shown to have a significant effect on the response in SI. The present study observes the effect of changing stimulus parameters of 25 Hz sinusoidal vertical skin displacement stimulation ("flutter" on a human subject's ability to discriminate between two adjacent or near-adjacent skin sites. Based on results obtained from recent neurophysiological studies of the SI response to different conditions of vibrotactile stimulation, we predicted that the addition of 200 Hz vibration to the same site that a two-point flutter stimulus was delivered on the skin would improve a subject's spatio-tactile acuity over that measured with flutter alone. Additionally, similar neurophysiological studies predict that the presence of either a 25 Hz flutter or 200 Hz vibration stimulus on the unattended hand (on the opposite side of the body from the site of two-point limen testing – the condition of bilateral stimulation – which has been shown to evoke less SI cortical activity than the contralateral-only stimulus condition would decrease a subject's ability to discriminate between two points on the skin. Results A Bekesy tracking method was employed to track a subject's ability to discriminate between two-point stimuli delivered to the skin. The distance between the two points of stimulation was varied on a trial-by-trial basis, and several different stimulus conditions were examined: (1 The "control" condition, in which 25 Hz flutter stimuli were delivered simultaneously to the two points on the skin of the attended hand, (2 the "complex" condition, in which a combination of 25 Hz flutter and 200 Hz vibration stimuli were delivered to the two points on the attended hand, and (3 a

  8. Somatosensory Space Abridged: Rapid Change in Tactile Localization Using a Motion Stimulus

    Science.gov (United States)

    Seizova-Cajic, Tatjana; Taylor, Janet L.

    2014-01-01

    Introduction Organization of tactile input into somatotopic maps enables us to localize stimuli on the skin. Temporal relationships between stimuli are important in maintaining the maps and influence perceived locations of discrete stimuli. This points to the spatiotemporal stimulation sequences experienced as motion as a potential powerful organizing principle for spatial maps. We ask whether continuity of the motion determines perceived location of areas in the motion path using a novel tactile stimulus designed to ‘convince’ the brain that a patch of skin does not exist by rapidly skipping over it. Method Two brushes, fixed 9 cm apart, moved back and forth along the forearm (at 14.5 cm s−1), crossing a 10-cm long ‘occluder’, which prevented skin stimulation in the middle of the motion path. Crucially, only one brush contacted the skin at any one time, and the occluder was traversed almost instantaneously. Participants pointed with the other arm towards the felt location of the brush when it was briefly halted during repetitive motion, and also reported where they felt they had been brushed. Results Participants did not report the 10-cm gap in stimulation – the motion path was perceptually completed. Pointing results showed that brush path was ‘abridged’: locations immediately on either side of the occluder, as well as location at the ends of the brush path, were perceived to be >3 cm closer to each other than in the control condition (F(1,9) = 7.19; p = .025 and F(1,9) = 6.02, p = .037 respectively). This bias increased with prolonged stimulation. Conclusions An illusion of completion induced by our Abridging stimulus is accompanied by gross mislocalization, suggesting that motion determines perceived locations. The effect reveals the operation of Gestalt principles in touch and suggests the existence of dynamic maps that quickly adjust to the current input pattern. PMID:24603595

  9. The effect of stimulus context on the buildup to stream segregation

    Directory of Open Access Journals (Sweden)

    Jonathan eSussman-Fort

    2014-04-01

    Full Text Available Stream segregation is the process by which the auditory system disentangles the mixture of sound inputs into discrete sources that cohere across time. The length of time required for this to occur is termed the ‘buildup’ period. In the current study, we used the buildup period as an index of how quickly sounds are segregated into constituent parts. Specifically, we tested the hypothesis that stimulus context impacts the timing of the buildup and, therefore, affects when stream segregation is detected. To measure the timing of the buildup we recorded the Mismatch Negativity component (MMN of event-related brain potentials (ERPs, during passive listening, to determine when the streams were neurophysiologically segregated. In each condition, a pattern of repeating low (L and high (H tones (L-L-H was presented in trains of stimuli separated by silence, with the H tones forming a simple intensity oddball paradigm and the L tones serving as distractors. To determine the timing of the buildup, probe tones occurred in two positions of the trains, early (within the buildup period and late (past the buildup period. The context was manipulated by presenting roving versus non-roving frequencies across trains in two conditions. MMNs were elicited by intensity probe tones in the Non-Roving condition (early and late positions and the Roving condition (late position only indicating that neurophysiologic segregation occurred faster in the Non-Roving condition. This suggests a shorter buildup period when frequency was repeated from train to train. Overall, our results demonstrate that the dynamics of the environment influence the way in which the auditory system extracts regularities from the input. The results support the hypothesis that the buildup to segregation is highly dependent upon stimulus context and that the auditory system works to maintain a consistent representation of the environment when no new information suggests that reanalyzing the scene

  10. [Sustainable diet: history lessons].

    Science.gov (United States)

    Fatati, Giuseppe

    2015-11-01

    Global dietary patterns changed dramatically in the past 50 years, presenting both a boom and a threat to the health and well-being of populations everywhere. We need sustainable diets, with low-input, local and seasonal agro-ecological food productions as well as short distance production-consumption nets for fair trade. The development of a global food system able to guarantee everyone a balanced food intake requires health professionals an awareness and a commitment to increasingly complex education. Dietary changes such as the adherence of to the Mediterranean Dietary Pattern can reduce the environmental footprint and thus the use of natural resources. Increased focus on improving the utilization of freshwater fishes and the correct use of the waters of rivers and lakes should also be encouraged. Cultural heritage, food quality and culinary skills are other key aspects determining sustainable dietary patterns and food security. The Mediterranean street food (Mediterraneità), for intrinsic characteristics, can represent valid model to address the main issues concerning the sustainable food system. The issues of sustainability offer a great opportunity to nutritional science and scientists to play a more central role in the political analysis of future food systems. We are confident that preserve the past helps us understand the present and build for the future, the Mediterranean lifestyle is much more than the Mediterranean diet and, finally, the rivers and the lakes may be our future.

  11. 7 CFR 3430.607 - Stakeholder input.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.607 Section 3430.607... § 3430.607 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, request for input and/or via Web site), as well as through a notice in the...

  12. 7 CFR 3430.907 - Stakeholder input.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.907 Section 3430.907... Program § 3430.907 Stakeholder input. CSREES shall seek and obtain stakeholder input through a variety of forums (e.g., public meetings, requests for input and/or Web site), as well as through a notice in the...

  13. Sustained Attention Ability Affects Simple Picture Naming

    Directory of Open Access Journals (Sweden)

    Suzanne R. Jongman

    2017-07-01

    Full Text Available Sustained attention has previously been shown as a requirement for language production. However, this is mostly evident for difficult conditions, such as a dual-task situation. The current study provides corroborating evidence that this relationship holds even for simple picture naming. Sustained attention ability, indexed both by participants’ reaction times and individuals’ hit rate (the proportion of correctly detected targets on a digit discrimination task, correlated with picture naming latencies. Individuals with poor sustained attention were consistently slower and their RT distributions were more positively skewed when naming pictures compared to individuals with better sustained attention. Additionally, the need to sustain attention was manipulated by changing the speed of stimulus presentation. Research has suggested that fast event rates tax sustained attention resources to a larger degree than slow event rates. However, in this study the fast event rate did not result in increased difficulty, neither for the picture naming task nor for the sustained attention task. Instead, the results point to a speed-accuracy trade-off in the sustained attention task (lower accuracy but faster responses in the fast than in the slow event rate, and to a benefit for faster rates in the picture naming task (shorter naming latencies with no difference in accuracy. Performance on both tasks was largely comparable, supporting previous findings that sustained attention is called upon during language production.

  14. Sustainable consumption

    DEFF Research Database (Denmark)

    Prothero, Andrea; Dobscha, Susan; Freund, Jim

    2011-01-01

    This essay explores sustainable consumption and considers possible roles for marketing and consumer researchers and public policy makers in addressing the many sustainability challenges that pervade our planet. Future research approaches to this interdisciplinary topic need to be comprehensive...... and systematic and will benefit from a variety of different perspectives. There are a number of opportunities for future research, and three areas are explored in detail. First, the essay considers the inconsistency between the attitudes and behaviors of consumers with respect to sustainability; next, the agenda...... is broadened to explore the role of individual citizens in society; and finally, a macro institutional approach to fostering sustainability is explored. Each of these areas is examined in detail and possible research avenues and public policy initiatives are considered within each of these separate...

  15. Stabilizing Sustainability

    DEFF Research Database (Denmark)

    Reitan Andersen, Kirsti

    The publication of the Brundtland Report in 1987 put the topic of sustainable development on the political and corporate agenda. Defining sustainable development as “a development that meets the needs of the future without compromising the ability of future generations to meet their own needs......” (WCED, 1987, p. 43), the Report also put a positive spin on the issue of sustainability by upholding capitalist beliefs in the possibility of infinite growth in a world of finite resources. While growth has delivered benefits, however, it has done so unequally and unsustainably. This thesis focuses...... on the textile and fashion industry, one of the world’s most polluting industries and an industry to some degree notorious for leading the ‘race to the bottom’ in global labour standards. Despite being faced with increasing demands to practise sustainability, most textile and fashion companies continue to fail...

  16. Sustainability reporting

    NARCIS (Netherlands)

    Kolk, A.

    2005-01-01

    This article gives an overview of developments in sustainability (also sometimes labelled corporate social responsibility) reporting. The article will first briefly indicate how accountability on social and environmental issues started, already in the 1970s when social reports were published.

  17. Sustainable Cities

    DEFF Research Database (Denmark)

    Georg, Susse; Garza de Linde, Gabriela Lucía

    Judging from the number of communities and cities striving or claiming to be sustainable and how often eco-development is invoked as the means for urban regeneration, it appears that sustainable and eco-development have become “the leading paradigm within urban development” (Whitehead 2003......), urban design competitions are understudied mechanisms for bringing about field level changes. Drawing on actor network theory, this paper examines how urban design competitions may bring about changes within the professional field through the use of intermediaries such as a sustainable planning....../assessment tool. The context for our study is urban regeneration in one Danish city, which had been suffering from industrial decline and which is currently investing in establishing a “sustainable city”. Based on this case study we explore how the insights and inspiration evoked in working with the tool...

  18. Sustainable responsibilities?

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    2015-01-01

    This working paper analyzes the conceptions of corporate responsibility for sustainable development in EU policies on CSR. The notion of corporate responsibility has until recently been limited to economical and legal responsibilities. Based on this narrow conception of corporate responsibility.......e. a combination of destruction and construction, this chapter will deconstruct conceptions of responsibility for sustainable development in these EU documents on CSR. A deconstructive conceptual analysis involves destructing dominant interpretations of a text and allowing for constructions of alternative...... such as sustainability actually means, but on what the concept says and does not say. A deconstructive analysis of EU policies on CSR, then, pinpoints that such policies are sites of conceptual struggles. This kind of analysis is suitable for studying conceptions of corporate responsibility for sustainable development...

  19. Agriculture: Sustainability

    Science.gov (United States)

    Sustainability creates and maintains the conditions under which humans and nature can exist in productive harmony, that permit fulfilling the food, feed, and fiber needs of our country and the social, economic and other requirements.

  20. Sustainable finance

    OpenAIRE

    Boersma-de Jong, Margreet F.

    2012-01-01

    Presentation for Springschool of Strategy, University of Groningen, 10 October 2012. The role of CSR is to stimulate ethical behaviour, and as a result, mutual trust in society. Advantage of CSR for the company and the evolution of CSR. From CSR to Sustainable Finance: how does CSR influence Sustainable Business Administration & Management Accounting, Financial Leadership and what is the importance of CSR in the financial sector

  1. SUSTAINABLE TRANSPORTATION

    Directory of Open Access Journals (Sweden)

    Linda STEG

    2007-01-01

    Full Text Available This paper discusses possible contributions of psychologists to sustainable transportation. It is argued that in order to reach sustainable transportation, among others, behaviour changes of individual car users are needed. As transport policies will be more effective if they target important antecedents of travel behaviour, first, factors influencing such behaviour are discussed. It is argued that car use is very attractive and sometimes even necessary for many different reasons. This implies that a combination of policies is called for, each targeting different factors that support car use and hinder the use of more sustainable modes of transport. Next, the paper elaborates on policy strategies that may be employed to achieve sustainable transportation by changing car use. Increasing the attractiveness of sustainable transport modes by means of pull measures seems not sufficient to reduce the level of car use. Besides, car use should be made less attractive by means of push measures to force drivers to reconsider their travel behaviour. The acceptability of such policies may be increased by clearly communicating the aim of these policies, and the expected positive consequences (e.g., less congestion, improved environmental quality. Moreover, possible negative effects for individual freedom may be compensated by implementing additional policies aimed at facilitating the use of sustainable transport modes.

  2. Sustainable markets for sustainable energy

    Energy Technology Data Exchange (ETDEWEB)

    Millan, J.; Smyser, C.

    1997-12-01

    The author discusses how the Inter-American Development Bank (IDB) is involved in sustainable energy development. It presently has 50 loans and grants for non conventional renewable energy projects and ten grants for efficiency programs for $600 and $17 million respectively, representing 100 MW of power. The IDB is concerned with how to create a sustainable market for sustainable energy projects. The IDB is trying to work with government, private sector, NGOs, trading allies, credit sources, and regulators to find proper roles for such projects. He discusses how the IDB is working to expand its vision and objectives in renewable energy projects in Central and South America.

  3. Are fish less responsive to a flow stimulus when swimming?

    Science.gov (United States)

    Feitl, Karla E; Ngo, Victoria; McHenry, Matthew J

    2010-09-15

    Fish use the lateral line system to sense the water flow created by a predator's strike. Despite its potential importance to the survival of a diversity of species, it is unclear whether this ability becomes compromised when a fish swims. Therefore, the present study compared the behavioral responsiveness of swimming and motionless zebrafish (Danio rerio) larvae when exposed to the flow of a suction-feeding predator. This flow was generated with an impulse chamber, which is a device that we developed to generate a repeatable stimulus with a computer-controlled servo motor. Using high-speed video recordings, we found that about three-quarters (0.76, N=121) of motionless larvae responded to the stimulus with an escape response. These larvae were 66% more likely to respond to flow directed perpendicular than flow running parallel to the body. Swimming larvae exhibited a 0.40 response probability and were therefore nearly half as likely to respond to flow as motionless larvae. However, the latency between stimulus and response was unaffected by swimming or the direction of flow. Therefore, swimming creates changes in the hydrodynamics or neurophysiology of a larval fish that diminish the probability, but not the speed, of their response to a flow stimulus. These findings demonstrate a sensory benefit to the intermittent swimming behavior observed among a broad diversity of fishes.

  4. Stimulus Characteristics Affect Humor Processing in Individuals with Asperger Syndrome

    Science.gov (United States)

    Samson, Andrea C.; Hegenloh, Michael

    2010-01-01

    The present paper aims to investigate whether individuals with Asperger syndrome (AS) show global humor processing deficits or whether humor comprehension and appreciation depends on stimulus characteristics. Non-verbal visual puns, semantic and Theory of Mind cartoons were rated on comprehension, funniness and the punchlines were explained. AS…

  5. Molecular Mechanisms of Olfactory Responses to Stimulus Mixtures

    Science.gov (United States)

    1991-02-26

    transduction process which transmits stimulus-encoded information across the plasma membrane. A variety of biochemical and electrophysiologcl...preparations were then resolved in SDS-polyacrylamide gels, transferred to Westran mambranes and probed with each of the three antibodies described in

  6. The Effects of Signaling Stimulus Presentation during Noncontingent Reinforcement

    Science.gov (United States)

    Gouboth, Djimir; Wilder, David A.; Booher, John

    2007-01-01

    The effects of signaling the return of items or attention during treatment with noncontingent reinforcement were examined. First, functional analyses showed that the problem behavior exhibited by 2 teenagers with developmental disabilities was sensitive to social positive reinforcement. Next, delivery of the stimulus that maintained problem…

  7. Combining Stimulus Fading, Reinforcement, and Extinction To Treat Food Refusal.

    Science.gov (United States)

    Freeman, Kurt A.; Piazza, Cathleen C.

    1998-01-01

    The food refusal of a 6-year-old girl with autism and destructive behavior was treated using stimulus fading, reinforcement, and escape extinction. Intake increased, and compliance with prompting procedures remained relatively stable despite the increased consumption requirement. (Author/CR)

  8. Salivary conditioning with antennal gustatory unconditioned stimulus in an insect.

    Science.gov (United States)

    Watanabe, Hidehiro; Sato, Chihiro; Kuramochi, Tomokazu; Nishino, Hiroshi; Mizunami, Makoto

    2008-07-01

    Classical conditioning of olfactory conditioning stimulus (CS) with gustatory unconditioned stimulus (US) in insects has been used as a pertinent model for elucidation of neural mechanisms underlying learning and memory. However, a conditioning system in which stable intracellular recordings from brain neurons are feasibly obtained while monitoring the conditioning effect has remained to be established. Recently, we found classical conditioning of salivation in cockroaches Periplaneta americana, in which an odor was associated with sucrose solution applied to the mouth, and this conditioning could be monitored by activities of salivary neurons. Application of gustatory US to the mouth, however, leads to feeding movement accompanying a movement of the brain that prevents stable recordings from brain neurons. Here we investigated whether a gustatory stimulus presented to an antenna could serve as an effective US for producing salivary conditioning. Presentation of sucrose or sodium chloride solution to an antenna induced salivation and also increased activities of salivary neurons. A single pairing trial of an odor with antennal presentation of sucrose or sodium chloride solution produced conditioning of salivation or of activities of salivary neurons. Five pairing trials led to a conditioning effect that lasted for one day. Water or tactile stimulus presented to an antenna was not effective for producing conditioning. The results demonstrate that gustatory US presented to an antenna is as effective as that presented to the mouth for producing salivary conditioning. This conditioning system provides a useful model for studying the neural basis of learning at the level of singly identifiable neurons.

  9. Promoting Response Variability and Stimulus Generalization in Martial Arts Training

    Science.gov (United States)

    Harding, Jay W.; Wacker, David P.; Berg, Wendy K.; Rick, Gary; Lee, John F.

    2004-01-01

    The effects of reinforcement and extinction on response variability and stimulus generalization in the punching and kicking techniques of 2 martial arts students were evaluated across drill and sparring conditions. During both conditions, the students were asked to demonstrate different techniques in response to an instructor's punching attack.…

  10. Compound Stimulus Extinction Reduces Spontaneous Recovery in Humans

    Science.gov (United States)

    Coelho, Cesar A. O.; Dunsmoor, Joseph E.; Phelps, Elizabeth A.

    2015-01-01

    Fear-related behaviors are prone to relapse following extinction. We tested in humans a compound extinction design ("deepened extinction") shown in animal studies to reduce post-extinction fear recovery. Adult subjects underwent fear conditioning to a visual and an auditory conditioned stimulus (CSA and CSB, respectively) separately…

  11. A Dynamic Stimulus-Driven Model of Signal Detection

    Science.gov (United States)

    Turner, Brandon M.; Van Zandt, Trisha; Brown, Scott

    2011-01-01

    Signal detection theory forms the core of many current models of cognition, including memory, choice, and categorization. However, the classic signal detection model presumes the a priori existence of fixed stimulus representations--usually Gaussian distributions--even when the observer has no experience with the task. Furthermore, the classic…

  12. Multidimensional Vector Model of Stimulus-Response Compatibility

    Science.gov (United States)

    Yamaguchi, Motonori; Proctor, Robert W.

    2012-01-01

    The present study proposes and examines the multidimensional vector (MDV) model framework as a modeling schema for choice response times. MDV extends the Thurstonian model, as well as signal detection theory, to classification tasks by taking into account the influence of response properties on stimulus discrimination. It is capable of accounting…

  13. Psilocybin-induced stimulus control in the rat.

    Science.gov (United States)

    Winter, J C; Rice, K C; Amorosi, D J; Rabin, R A

    2007-10-01

    Although psilocybin has been trained in the rat as a discriminative stimulus, little is known of the pharmacological receptors essential for stimulus control. In the present investigation rats were trained with psilocybin and tests were then conducted employing a series of other hallucinogens and presumed antagonists. An intermediate degree of antagonism of psilocybin was observed following treatment with the 5-HT(2A) receptor antagonist, M100907. In contrast, no significant antagonism was observed following treatment with the 5-HT(1A/7) receptor antagonist, WAY-100635, or the DA D(2) antagonist, remoxipride. Psilocybin generalized fully to DOM, LSD, psilocin, and, in the presence of WAY-100635, DMT while partial generalization was seen to 2C-T-7 and mescaline. LSD and MDMA partially generalized to psilocybin and these effects were completely blocked by M-100907; no generalization of PCP to psilocybin was seen. The present data suggest that psilocybin induces a compound stimulus in which activity at the 5-HT(2A) receptor plays a prominent but incomplete role. In addition, psilocybin differs from closely related hallucinogens such as 5-MeO-DMT in that agonism at 5-HT(1A) receptors appears to play no role in psilocybin-induced stimulus control.

  14. Fechnerian metrics in unidimensional and multidimensional stimulus spaces.

    Science.gov (United States)

    Dzhafarov, E N; Colonius, H

    1999-06-01

    A new theory is proposed for subjective (Fechnerian) distances among stimuli in a continuous stimulus space of arbitrary dimensionality. Each stimulus in such a space is associated with a psychometric function that determines probabilities with which it is discriminated from other stimuli, and a certain measure of its discriminability from its infinitesimally close neighboring stimuli is computed from the shape of this psychometric function in the vicinity of its minimum. This measure of discriminability can be integrated along any path connecting any two points in the stimulus space, yielding the psychometric length of this path. The Fechnerian distance between two stimuli is defined as the infimum of the psychometric lengths of all paths connecting the two stimuli. For a broad class of models defining the dichotomy of response bias versus discriminability, the Fechnerian distances are invariant under response bias changes. In the case in which physically multidimensional stimuli are discriminated along some unidimensional subjective attribute, a systematic construction of the Fechnerian metric leads to a resolution of the long-standing controversy related to the numbers of just-noticeable differences between isosensitivity curves. It is argued that for unidimensional stimulus continua, the proposed theory is close to the intended meaning of Fechner's original theory.

  15. Distraction Reduces Both Early and Late Electrocutaneous Stimulus Evoked Potentials

    NARCIS (Netherlands)

    Blom, J.H.G.; Wiering, Caro H.; van der Lubbe, Robert Henricus Johannes

    2012-01-01

    Previous electroencephalography studies revealed mixed effects of sustained distraction on early negative and later positive event-related potential components evoked by electrocutaneous stimuli. In our study we further examined the influence of sustained distraction to clarify these discrepancies.

  16. Alternative aviation jet fuel sustainability evaluation report - task 3 : sustainability criteria and rating systems for the use in aircraft alternative fuel supply chain

    Science.gov (United States)

    2013-03-31

    This report identifies criteria that can be used to evaluate the sustainability of biofuels introduced into the aviation fuel supply chain. It describes the inputs, criteria and outputs that can be used in a sustainability rating system. It identifie...

  17. Discriminative stimulus effects of nalbuphine in rhesus monkeys.

    Science.gov (United States)

    Gerak, L R; France, C P

    1996-02-01

    Three rhesus monkeys discriminated between 0.178 mg/kg of nalbuphine and saline while responding under a fixed-ratio 5 schedule of stimulus-shock termination. Nalbuphine produced dose-related increases in drug-lever responding with > or = 90% of responses occurring on the drug lever at doses larger than 0.1 mg/kg. The duration of action of the discriminative stimulus effects of nalbuphine was less than 5.25 hr. Rank order potency of compounds that substituted for the nalbuphine discriminative stimulus (i.e., > or = 90% responding on the nalbuphine lever) in all three subjects was fentanyl > butorphanol > methadone > morphine. Compounds that did not substitute completely in all monkeys included the kappa agonists ethylketocyclazocine, enadoline, spiradoline and U-50,488 and the nonopioids cocaine, d-amphetamine, clonidine, ketamine and phencyclidine. Naltrexone antagonized the discriminative stimulus effects of nalbuphine, shifting the nalbuphine dose-effect curve in a manner that was consistent with mu receptor mediation. Results from the current study demonstrate that, in rhesus monkeys, the discriminative stimulus effects of nalbuphine are mediated by mu opioid receptors. Although there is evidence suggesting that nalbuphine has kappa agonist effects (e.g., subjective effects in humans), results from several studies, including the current study, strongly suggest that in rhesus monkeys nalbuphine does not exert agonist actions at kappa receptors. Moreover, these data indicate that differences in behavioral effects between nalbuphine and prototypic mu opioids (e.g., morphine) probably result from differences in activity (e.g., efficacy) at mu receptors rather than any kappa agonist actions of nalbuphine.

  18. Discriminative stimulus effects of pregnanolone in rhesus monkeys.

    Science.gov (United States)

    Gerak, Lisa R; France, Charles P

    2014-01-01

    Neuroactive steroids and benzodiazepines can positively modulate GABA by acting at distinct binding sites on synaptic GABA(A) receptors. Although these receptors are thought to mediate the behavioral effects of both benzodiazepines and neuroactive steroids, other receptors (e.g., extrasynaptic GABA(A), N-methyl-D-aspartate (NMDA), σ₁, or 5-HT₃ receptors) might contribute to the effects of neuroactive steroids, accounting for differences among positive modulators. The current study established the neuroactive steroid pregnanolone as a discriminative stimulus to determine whether actions in addition to positive modulation of synaptic GABA(A) receptors might contribute to its discriminative stimulus effects. Four rhesus monkeys discriminated 5.6 mg/kg pregnanolone while responding under a fixed-ratio 10 schedule of stimulus-shock termination. Positive modulators acting at benzodiazepine, barbiturate, or neuroactive steroid sites produced ≥80 % pregnanolone-lever responding, whereas drugs acting primarily at receptors other than synaptic GABA(A) receptors, such as extrasynaptic GABA(A), NMDA, σ₁, and 5-HT₃ receptors, produced vehicle-lever responding. Flumazenil antagonized the benzodiazepines midazolam and flunitrazepam, with Schild analyses yielding slopes that did not deviate from unity and pA₂ values of 7.39 and 7.32, respectively. Flumazenil did not alter the discriminative stimulus effects of pregnanolone. While these results do not exclude the possibility that pregnanolone acts at receptors other than synaptic GABA(A) receptors, they indicate a primary and possibly exclusive role of synaptic GABA(A) receptors in its discriminative stimulus effects. Reported differences in the effects of benzodiazepines and neuroactive steroids are not due to differences in their actions at synaptic GABA(A) receptors.

  19. Temporal firing reliability in response to periodic synaptic inputs

    Science.gov (United States)

    Hunter, John D.; Milton, John G.

    1998-03-01

    Reliable spike timing in the presence of noise is a prerequisite for a spike timing code. Previously we demonstrated that there is an intimate relationship between the phase locked firing patterns and spike timing reliability in the presence of noise: stable 1:m phase-locking generate reliable firing times; n:m phase-locked solutions where n neq 1 generate significantly less reliable spike times, where n is the number of spikes in m cycles of the stimulus. Here we compare spike timing reliability in an Aplysia motoneuron to that in a leaky integrate-and-fire neuron receiving either realistic periodic excitatory (EPSC) or inhibitory (IPSC) post-synaptic currents. For the same frequency and for identical synaptic time courses, EPSCs and IPSCs have opposite effects on spike timing reliability. This effect is shown to be a direct consequence of changes in the DC component of the input. Thus spike-time reliability is sensitively controlled by the interplay between the frequency and DC component of input to the neuron.

  20. The Role of Left Occipitotemporal Cortex in Reading: Reconciling Stimulus, Task, and Lexicality Effects

    Science.gov (United States)

    Humphries, Colin; Desai, Rutvik H.; Seidenberg, Mark S.; Osmon, David C.; Stengel, Ben C.; Binder, Jeffrey R.

    2013-01-01

    Although the left posterior occipitotemporal sulcus (pOTS) has been called a visual word form area, debate persists over the selectivity of this region for reading relative to general nonorthographic visual object processing. We used high-resolution functional magnetic resonance imaging to study left pOTS responses to combinatorial orthographic and object shape information. Participants performed naming and visual discrimination tasks designed to encourage or suppress phonological encoding. During the naming task, all participants showed subregions within left pOTS that were more sensitive to combinatorial orthographic information than to object information. This difference disappeared, however, when phonological processing demands were removed. Responses were stronger to pseudowords than to words, but this effect also disappeared when phonological processing demands were removed. Subregions within the left pOTS are preferentially activated when visual input must be mapped to a phonological representation (i.e., a name) and particularly when component parts of the visual input must be mapped to corresponding phonological elements (consonant or vowel phonemes). Results indicate a specialized role for subregions within the left pOTS in the isomorphic mapping of familiar combinatorial visual patterns to phonological forms. This process distinguishes reading from picture naming and accounts for a wide range of previously reported stimulus and task effects in left pOTS. PMID:22505661

  1. Roundtabling Sustainability

    DEFF Research Database (Denmark)

    Ponte, Stefano

    2014-01-01

    The willingness of public authority to delegate social and environmental regulation to the private sector has varied from sector to sector, but has often led to the establishment of ‘voluntary’ standards and certifications on sustainability. Many of these have taken the form of ‘stewardship...... councils’ and ‘sustainability roundtables’ and have been designed around a set of institutional features seeking to establish legitimacy, fend off possible criticism, and ‘sell’ certifications to potential users. The concept of ‘roundtabling’ emphasizes the fitting a variety of commodity......-specific sustainability situations into a form that not only ‘hears more voices’ (as in ‘multi-stakeholder’), but also portrays to give them equal standing at the table of negotiations (roundtable), thus raising higher expectations on accountability, transparency and inclusiveness. In this article, I examine to what...

  2. Sustainability Evaluation.

    Science.gov (United States)

    Stichnothe, Heinz

    2017-03-17

    The long-term substitution of fossil resources can only be achieved through a bio-based economy, with biorefineries and bio-based products playing a major role. However, it is important to assess the implications of the transition to a bio-based economy. Life cycle-based sustainability assessment is probably the most suitable approach to quantify impacts and to identify trade-offs at multiple levels. The extended utilisation of biomass can cause land use change and affect food security of the most vulnerable people throughout the world. Although this is mainly a political issue and governments should be responsible, the responsibility is shifted to companies producing biofuels and other bio-based products. Organic wastes and lignocellulosic biomass are considered to be the preferred feedstock for the production of bio-based products. However, it is unlikely that a bio-based economy can rely only on organic wastes and lignocellulosic biomass.It is crucial to identify potential problems related to socio-economic and environmental issues. Currently there are many approaches to the sustainability of bio-based products, both quantitative and qualitative. However, results of different calculation methods are not necessarily comparable and can cause confusion among decision-makers, stakeholders and the public.Hence, a harmonised, globally agreed approach would be the best solution to secure sustainable biomass/biofuels/bio-based chemicals production and trade, and to avoid indirect effects (e.g. indirect land use change). However, there is still a long way to go.Generally, the selection of suitable indicators that serve the purpose of sustainability assessment is very context-specific. Therefore, it is recommended to use a flexible and modular approach that can be adapted to various purposes. A conceptual model for the selection of sustainability indicators is provided that facilitates identifying suitable sustainability indicators based on relevance and significance in a

  3. Repositioning Recitation Input in College English Teaching

    Science.gov (United States)

    Xu, Qing

    2009-01-01

    This paper tries to discuss how recitation input helps overcome the negative influences on the basis of second language acquisition theory and confirms the important role that recitation input plays in improving college students' oral and written English.

  4. Efferent Vestibular Neurons Show Homogenous Discharge Output But Heterogeneous Synaptic Input Profile In Vitro.

    Directory of Open Access Journals (Sweden)

    Miranda A Mathews

    Full Text Available Despite the importance of our sense of balance we still know remarkably little about the central control of the peripheral balance system. While previous work has shown that activation of the efferent vestibular system results in modulation of afferent vestibular neuron discharge, the intrinsic and synaptic properties of efferent neurons themselves are largely unknown. Here we substantiate the location of the efferent vestibular nucleus (EVN in the mouse, before characterizing the input and output properties of EVN neurons in vitro. We made transverse serial sections through the brainstem of 4-week-old mice, and performed immunohistochemistry for calcitonin gene-related peptide (CGRP and choline acetyltransferase (ChAT, both expressed in the EVN of other species. We also injected fluorogold into the posterior canal and retrogradely labelled neurons in the EVN of ChAT:: tdTomato mice expressing tdTomato in all cholinergic neurons. As expected the EVN lies dorsolateral to the genu of the facial nerve (CNVII. We then made whole-cell current-, and voltage-clamp recordings from visually identified EVN neurons. In current-clamp, EVN neurons display a homogeneous discharge pattern. This is characterized by a high frequency burst of action potentials at the onset of a depolarizing stimulus and the offset of a hyperpolarizing stimulus that is mediated by T-type calcium channels. In voltage-clamp, EVN neurons receive either exclusively excitatory or inhibitory inputs, or a combination of both. Despite this heterogeneous mixture of inputs, we show that synaptic inputs onto EVN neurons are predominantly excitatory. Together these findings suggest that the inputs onto EVN neurons, and more specifically the origin of these inputs may underlie EVN neuron function.

  5. 7 CFR 3430.15 - Stakeholder input.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Stakeholder input. 3430.15 Section 3430.15... Stakeholder input. Section 103(c)(2) of the Agricultural Research, Extension, and Education Reform Act of 1998 (AREERA) (7 U.S.C. 7613(c)(2)) requires the Secretary to solicit and consider input on each program RFA...

  6. Experimental System for Investigation of Visual Sensory Input in Postural Feedback Control

    Directory of Open Access Journals (Sweden)

    Jozef Pucik

    2012-01-01

    Full Text Available The human postural control system represents a biological feedback system responsible for maintenance of upright stance. Vestibular, proprioceptive and visual sensory inputs provide the most important information into the control system, which controls body centre of mass (COM in order to stabilize the human body resembling an inverted pendulum. The COM can be measured indirectly by means of a force plate as the centre of pressure (COP. Clinically used measurement method is referred to as posturography. In this paper, the conventional static posturography is extended by visual stimulation, which provides insight into a role of visual information in balance control. Visual stimuli have been designed to induce body sway in four specific directions – forward, backward, left and right. Stabilograms were measured using proposed single-PC based system and processed to calculate velocity waveforms and posturographic parameters. The parameters extracted from pre-stimulus and on-stimulus periods exhibit statistically significant differences.

  7. Sustainable Soesterkwartier

    NARCIS (Netherlands)

    Abrahams, H.; Goosen, H.; Jong, de F.; Sickmann, J.; Prins, D.

    2010-01-01

    The municipality of Amersfoort wants to construct an endurable and sustainable eco-town in the Soesterkwartier neighbourhood, by taking future climate change into account. The impact of climate change at the location of the proposed eco-town was studied by a literature review.

  8. Sustainable agriculture

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

    New farming techniques, better food security. Since 1970, IDRC-supported research has introduced sustainable agricultural practices to farmers and communities across the devel- oping world. The result: higher productivity, less poverty, greater food security, and a healthier environment. Opportunities grow on trees in ...

  9. Sustainable Development

    African Journals Online (AJOL)

    Tsegai Berhane Ghebretekle

    Abstract. This article examines the concept of sustainable development after the Post-. 2015 Paris Climate Change Agreement with particular emphasis on Ethiopia. Various African countries are vulnerable to climate change, as is evidenced by recent droughts. Ethiopia is selected as a case study in light of its pace in.

  10. Sustainable machining

    CERN Document Server

    2017-01-01

    This book provides an overview on current sustainable machining. Its chapters cover the concept in economic, social and environmental dimensions. It provides the reader with proper ways to handle several pollutants produced during the machining process. The book is useful on both undergraduate and postgraduate levels and it is of interest to all those working with manufacturing and machining technology.

  11. Architecture Sustainability

    NARCIS (Netherlands)

    Avgeriou, Paris; Stal, Michael; Hilliard, Rich

    2013-01-01

    Software architecture is the foundation of software system development, encompassing a system's architects' and stakeholders' strategic decisions. A special issue of IEEE Software is intended to raise awareness of architecture sustainability issues and increase interest and work in the area. The

  12. Sustainability reporting

    NARCIS (Netherlands)

    Kolk, A.

    2005-01-01

    This article gives an overview of developments in sustainability (also sometimes labelled corporate social responsibility) reporting. It The article will first briefly indicate how accountability on social and environmental issues started, already in the 1970s when social reports were published.

  13. Sustainable finance

    NARCIS (Netherlands)

    dr. Margreet F. Boersma-de Jong

    2012-01-01

    Presentation for Springschool of Strategy, University of Groningen, 10 October 2012. The role of CSR is to stimulate ethical behaviour, and as a result, mutual trust in society. Advantage of CSR for the company and the evolution of CSR. From CSR to Sustainable Finance: how does CSR influence

  14. Stimulus processing and associative learning in Wistar and WKHA rats.

    Science.gov (United States)

    Chess, Amy C; Keene, Christopher S; Wyzik, Elizabeth C; Bucci, David J

    2005-06-01

    This study assessed basic learning and attention abilities in Wistar-Kyoto hyperactive (WKHA) rats using appetitive conditioning preparations. Two measures of conditioned responding to a visual stimulus, orienting behavior (rearing on the hind legs), and food cup behavior (placing the head inside the recessed food cup) were measured. In Experiment 1, simple conditioning, but not extinction, was impaired in WKHA rats compared with Wistar rats. In Experiment 2, nonreinforced presentations of the visual cue preceded the conditioning sessions. WKHA rats displayed less orienting behavior than Wistar rats but comparable levels of food cup behavior. These data suggest that WKHA rats exhibit specific abnormalities in attentional processing as well as in learning stimulus-reward relationships. (c) 2005 APA, all rights reserved.

  15. Levels of processing and Eye Movements: A Stimulus driven approach

    DEFF Research Database (Denmark)

    Mulvey, Fiona Bríd

    2014-01-01

    movements from the effect of the changing nature of the stimulus is difficult. Characterising and confirming the parameters of levels of processing in eye movements requires measures with the explicit intention of systematically varying task demands while also taking account of individual differences....... This series of studies attempts to provide explanatory information for previous findings that saccade amplitude and fixation duration are indicative of levels of processing and to isolate top down influences on eye movements with a stimulus driven approach. This approach involves developing measures suitable...... to investigate individual differences in levels of processing within the normal population using existing constructs and tests of cognitive style. Study 4 investigates these stimuli and the eye movements of a clinical group with known interruption to the dorsal stream of processing, and subsequent isolated...

  16. Effects of stimulus duration on gustatory evoked potentials

    DEFF Research Database (Denmark)

    Rotvel, Camilla Arndal; Møller, Stine; Kivisaar, Kätlin

    . 19 normal-tasting subjects (10 females, mean age ± sd: 27 ± 3) were stimulated with aqueous 0.5g/L sucralose in between continuous periods of non-chlorinated tap water to avoid somatosensory onsets. The sucralose stimulus duration was either short (~0.6s) or long (~4s) and presented in random...... sucralose stimulation kept the GEP significant for longer and produced a larger peak occurring at ~1.6sec (t-test) while maintaining the characteristic negative temporal deflection as opposed to the short stimulation which produced frontal activity. Instances of brain response to varying NaCl stimulus...... sucralose stimulation duration resulted in larger GEP peak amplitude above the gustatory cortex and may indicate higher intensity perception (Kelling and Halpern, 1988)....

  17. Preoptic inputs and mechanisms that regulate maternal responsiveness.

    Science.gov (United States)

    Dobolyi, A; Grattan, D R; Stolzenberg, D S

    2014-10-01

    The preoptic area is a well-established centre for the control of maternal behaviour. An intact medial preoptic area (mPOA) is required for maternal responsiveness because lesion of the area abolishes maternal behaviours. Although hormonal changes in the peripartum period contribute to the initiation of maternal responsiveness, inputs from pups are required for its maintenance. Neurones are activated in different parts of the mPOA in response to pup exposure. In the present review, we summarise the potential inputs to the mPOA of rodent dams from the litter that can activate mPOA neurones. The roles of potential indirect effects through increased prolactin levels, as well as neuronal inputs to the preoptic area, are described. Recent results on the pathway mediating the effects of suckling to the mPOA suggest that neurones containing the neuropeptide tuberoinfundibular peptide of 39 residues in the posterior thalamus are candidates for conveying the suckling information to the mPOA. Although the molecular mechanism through which these inputs alter mPOA neurones to support the maintenance of maternal responding is not yet known, altered gene expression is a likely candidate. Here, we summarise gene expression changes in the mPOA that have been linked to maternal behaviour and explore the idea that chromatin remodelling during mother-infant interactions mediates the long-term alterations in gene expression that sustain maternal responding. © 2014 British Society for Neuroendocrinology.

  18. Stimulus determinants of the phenomenon of change blindness

    Directory of Open Access Journals (Sweden)

    Gusev, Alexey N.

    2014-03-01

    Full Text Available This article describes techniques and procedures that are used to research the changeblindness phenomenon. The role of stimulus parameters in completing a visual task (detecting changes was investigated. The following parameters of visual stimuli varied in a chronometric experiment: the number of objects, their location in the stimulus space, and the shape of the objects (including a new object that attracts attention as well as various changes of single objects, such as appearance/disappearance, location shifts, changes of color and shape. The results of this study indicate that change blindness can have a different intensity (the time of detecting changes in flickering images depending on the number of objects, their location in the stimulus space (structured or randomized, and the type of change (the most complicated one was a change of color: 1.The number of objects has considerable influence on the intensity of change blindness and is the most powerful parameter. 2.The shape of the objects within the image is not crucial for change-detection time. 3..The spatial organization of the objects is important for the successful detection of changes. The changes are detected quicker in images with regular rather than random organization. 4.A distraction (in this case, a word that was substituted for an object doesn’t have any considerable influence on change detection. 5.Change-detection time increases as the interstimulus interval increases from 200 to 400 ms. 6.The detection of shifts and of appearance/disappearance is quicker than the detection of color change. These results let us create stimulus patterns for change-blindness experiments that differ in complexity, and thus we could examine a wide range of hypotheses about the function of the psychological mechanisms of spatial attention that are used to explain this phenomenon.

  19. Benzodiazepine-like discriminative stimulus effects of toluene vapor

    Science.gov (United States)

    Shelton, Keith L.; Nicholson, Katherine L.

    2013-01-01

    In vitro studies show that the abused inhalant toluene affects a number of ligand-gated ion channels. The two most consistently implicated of these are γ-aminobutyric acid type A (GABAA) receptors which are positively modulated by toluene and N-methyl-D-aspartate (NMDA) receptors which are negatively modulated by toluene. Behavioral studies also suggest an interaction of toluene with GABAA and/or NMDA receptors but it is unclear if these receptors underlie the abuse-related intoxicating effects of toluene. Seventeen B6SJLF1/J mice were trained using a two-choice operant drug discrimination procedure to discriminate 10 min of exposure to 2000 ppm toluene vapor from 10 min of exposure to air. The discrimination was acquired in a mean of 65 training sessions. The stimulus effects of 2000 ppm toluene vapor were exposure concentration-dependent but rapidly diminished following the cessation of vapor exposure. The stimulus effects of toluene generalized to the chlorinated hydrocarbon vapor perchloroethylene but not 1,1,2-trichloroethane nor the volatile anesthetic isoflurane. The competitive NMDA antagonist CGS-17955, the uncompetitive antagonist dizocilpine and the glycine-site antagonist L701,324 all failed to substitute for toluene. The classical nonselective benzodiazepines midazolam and chlordiazepoxide produced toluene-like stimulus effects but the alpha 1 subunit preferring positive GABAA modulator zaleplon failed to substitute for toluene. The barbiturates pentobarbital and methohexital and the GABAA-positive modulator neurosteroid allopregnanolone did not substitute for toluene. These data suggest that the stimulus effects of toluene may be at least partially mediated by benzodiazepine-like positive allosteric modulation of GABAA receptors containing alpha 2, 3 or 5 subunits. PMID:24436974

  20. Visual Distractors Disrupt Audiovisual Integration Regardless of Stimulus Complexity

    OpenAIRE

    Gibney, Kyla D.; Aligbe, Enimielen; Eggleston, Brady A.; Nunes, Sarah R.; Kerkhoff, Willa G.; Dean, Cassandra L.; Kwakye, Leslie D.

    2017-01-01

    The intricate relationship between multisensory integration and attention has been extensively researched in the multisensory field; however, the necessity of attention for the binding of multisensory stimuli remains contested. In the current study, we investigated whether diverting attention from well-known multisensory tasks would disrupt integration and whether the complexity of the stimulus and task modulated this interaction. A secondary objective of this study was to investigate individ...

  1. Visual hemispatial inattention: stimulus parameters and exploratory strategies.

    OpenAIRE

    Weintraub, S; Mesulam, M.M.

    1988-01-01

    Patients with unilateral hemispheric lesions were given visual target cancellation tasks. As expected, marked contralateral and less severe ipsilateral visual inattention were observed in patients with right-sided cerebral lesions whereas those with left-sided lesions showed only mild contralateral neglect. Stimulus material (shapes vs letters) and array (random vs structured) interacted in a complex manner to influence target detection only in patients with right-sided lesions. Furthermore, ...

  2. Decorrelated Input Dissociates Narrow Band γ Power and BOLD in Human Visual Cortex.

    Science.gov (United States)

    Butler, Russell; Bernier, Pierre-Michel; Lefebvre, Jérémie; Gilbert, Guillaume; Whittingstall, Kevin

    2017-05-31

    Although fMRI using the BOLD contrast is widely used for noninvasively mapping hemodynamic brain activity in humans, its exact link to underlying neural processing is poorly understood. Whereas some studies have reported that BOLD signals measured in visual cortex are tightly linked to neural activity in the narrow band γ (NBG) range, others have found a weak correlation between the two. To elucidate the mechanisms behind these conflicting findings, we hypothesized that BOLD reflects the strength of synaptic inputs to cortex, whereas NBG is more dependent on how well these inputs are correlated. To test this, we measured NBG, BOLD, and cerebral blood flow responses to stimuli that either correlate or decorrelate neural activity in human visual cortex. Next, we simulated a recurrent network model of excitatory and inhibitory neurons that reproduced in detail the experimental NBG and BOLD data. Results show that the visually evoked BOLD response was solely predicted by the sum of local inputs, whereas NBG was critically dependent on how well these inputs were correlated. In summary, the NBG-BOLD relationship strongly depends on the nature of sensory input to cortex: stimuli that increase the number of correlated inputs to visual cortex will increase NBG and BOLD in a similar manner, whereas stimuli that increase the number of decorrelated inputs will dissociate the two. The NBG-BOLD relationship is therefore not fixed but is rather highly dependent on input correlations that are both stimulus- and state-dependent. SIGNIFICANCE STATEMENT It is widely believed that γ oscillations in cortex are tightly linked to local hemodynamic activity. Here, we present experimental evidence showing how a stimulus can increase local blood flow to the brain despite suppressing γ power. Moreover, using a sophisticated model of cortical neurons, it is proposed that this occurs when synaptic input to cortex is strong yet decorrelated. Because input correlations are largely determined

  3. Input-dependent frequency modulation of cortical gamma oscillations shapes spatial synchronization and enables phase coding.

    Science.gov (United States)

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-02-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25-80Hz) may play a significant role in information processing, for example by neural grouping ('binding') and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency codes

  4. Input-Dependent Frequency Modulation of Cortical Gamma Oscillations Shapes Spatial Synchronization and Enables Phase Coding

    Science.gov (United States)

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-01-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25–80Hz) may play a significant role in information processing, for example by neural grouping (‘binding’) and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency

  5. Speech Prosody Across Stimulus Types for Individuals with Parkinson's Disease.

    Science.gov (United States)

    K-Y Ma, Joan; Schneider, Christine B; Hoffmann, Rüdiger; Storch, Alexander

    2015-01-01

    Up to 89% of the individuals with Parkinson's disease (PD) experience speech problem over the course of the disease. Speech prosody and intelligibility are two of the most affected areas in hypokinetic dysarthria. However, assessment of these areas could potentially be problematic as speech prosody and intelligibility could be affected by the type of speech materials employed. To comparatively explore the effects of different types of speech stimulus on speech prosody and intelligibility in PD speakers. Speech prosody and intelligibility of two groups of individuals with varying degree of dysarthria resulting from PD was compared to that of a group of control speakers using sentence reading, passage reading and monologue. Acoustic analysis including measures on fundamental frequency (F0), intensity and speech rate was used to form a prosodic profile for each individual. Speech intelligibility was measured for the speakers with dysarthria using direct magnitude estimation. Difference in F0 variability between the speakers with dysarthria and control speakers was only observed in sentence reading task. Difference in the average intensity level was observed for speakers with mild dysarthria to that of the control speakers. Additionally, there were stimulus effect on both intelligibility and prosodic profile. The prosodic profile of PD speakers was different from that of the control speakers in the more structured task, and lower intelligibility was found in less structured task. This highlighted the value of both structured and natural stimulus to evaluate speech production in PD speakers.

  6. Neurogenic vestibular evoked potentials using a tone pip auditory stimulus.

    Science.gov (United States)

    Papathanasiou, E S; Zamba-Papanicolaou, E; Pantziaris, M; Kleopas, K; Kyriakides, T; Papacostas, S; Pattichis, C; Iliopoulos, I; Piperidou, C

    2004-01-01

    To obtain neurogenic vestibular evoked potentials (NVESTEPs) with surface scalp recording using a tone pip auditory stimulus. Fourteen neurologically normal volunteers (Age range 26-45 years, 10 females and 4 males), and two patients with sensorineural hearing loss and possible multiple sclerosis respectively, were examined. Two channel recordings were obtained, the first channel being P3 referred to Fpz, and the second channel being P4 referred to Fpz. A 1 kHz tone pip stimulus with two cycles was delivered via headphones monoaurally with contralateral masking noise. A consistent negative wave with a mean absolute latency of 4.72 msec was obtained, which we have named N5. 25% of the ears tested had better responses at the ipsilateral parietal electrode. In the patient with bilateral sensorineural hearing loss, NVESTEPs was present, suggesting that the NVESTEP is not a cochlear response. In the patient with possible multiple sclerosis, an abnormal NVESTEP response and a normal BAEP response were found. Use of a tone-pip rather than a click auditory stimulus allows a lower click intensity to be used in the production of NVESTEP responses, leads to a shorter testing time, and is therefore more comfortable for the patient. This study adds to our impression that the NVESTEP may be a physiological response that can be used to assess the vestibular system and is different from the BAEP response. Further testing in patients with symptoms of dizziness and with disorders specific for the vestibular nerve is required.

  7. Accommodative Stimulus-Response Curve with Emoji Symbols

    Directory of Open Access Journals (Sweden)

    Robert Montés-Micó

    2017-01-01

    Full Text Available Purpose. To evaluate the static measurement of the accommodative stimulus-response curve with emoji symbols. Methods. The accommodative stimulus-response curve was measured in 18 subjects using a Hartmann-Shack sensor to obtain the objective accommodative response from the Zernike defocus term. Measurements were acquired at different accommodative demands, from 0 to 3 D with a step of 0.5 D. Detailed and nondetailed emoji targets were used with two different sizes, corresponding to the two most common visual angles used in smartphones. Results. A regression analysis was performed to fit the mean results obtained for each target. The determination coefficient was R2≥0.988 for all targets. For the detailed targets, the slopes for the averaged stimulus-response curve were 0.65 and 0.66 for the bigger and smaller sizes, respectively. For the nondetailed targets, the slopes were 0.60 and 0.58 for the bigger and smaller sizes, respectively. p values for these slopes were statistically significant for the two types of targets (p<0.01. Conclusions. Our results reveal that the replacement of a word or several words by detailed or nondetailed emoji symbols seems not to provoke a different accommodative response in normal subjects and under standard viewing conditions in the use of smartphones.

  8. Accommodative Stimulus-Response Curve with Emoji Symbols

    Science.gov (United States)

    Montés-Micó, Robert; Bernal-Molina, Paula; Ferrer-Blasco, Teresa

    2017-01-01

    Purpose To evaluate the static measurement of the accommodative stimulus-response curve with emoji symbols. Methods The accommodative stimulus-response curve was measured in 18 subjects using a Hartmann-Shack sensor to obtain the objective accommodative response from the Zernike defocus term. Measurements were acquired at different accommodative demands, from 0 to 3 D with a step of 0.5 D. Detailed and nondetailed emoji targets were used with two different sizes, corresponding to the two most common visual angles used in smartphones. Results A regression analysis was performed to fit the mean results obtained for each target. The determination coefficient was R2 ≥ 0.988 for all targets. For the detailed targets, the slopes for the averaged stimulus-response curve were 0.65 and 0.66 for the bigger and smaller sizes, respectively. For the nondetailed targets, the slopes were 0.60 and 0.58 for the bigger and smaller sizes, respectively. p values for these slopes were statistically significant for the two types of targets (p emoji symbols seems not to provoke a different accommodative response in normal subjects and under standard viewing conditions in the use of smartphones. PMID:29082040

  9. Discriminative stimulus and antinociceptive effects of dihydroetorphine in rhesus monkeys.

    Science.gov (United States)

    Gerak, Lisa R; Gauthier, Cheryl R A; France, Charles R A P

    2003-04-01

    Although dihydroetorphine has micro opioid agonist activity there is evidence to suggest that it is not identical to that of morphine. This study compared dihydroetorphine to other opioids under behavioral conditions that are sensitive to micro opioid agonism. The acute effects of dihydroetorphine, etorphine and morphine were evaluated using two procedures. In one procedure, monkeys received 3.2 mg/kg per day of morphine and discriminated naltrexone from saline while responding under a fixed-ratio 5 schedule of stimulus shock termination. In addition, a warm-water, tail-withdrawal procedure was used in untreated monkeys. When acutely deprived of morphine, monkeys responded on the naltrexone lever, and this effect was reversed by dihydroetorphine, etorphine and morphine. Each agonist produced the maximum (20-s latency) antinociceptive effect in 50 degrees C water. Naltrexone antagonized the discriminative stimulus and antinociceptive effects of dihydroetorphine and etorphine, although Schild analyses yielded large variability in slopes and pA(2) values. Naltrexone reversed established effects of dihydroetorphine and morphine in both procedures and pretreatment with dihydroetorphine (2, 6 or 24 h) did not alter the discriminative stimulus effects of morphine. Taken together, these data support the notion that dihydroetorphine is a micro agonist with a short duration of action; however, variability in antagonism of dihydroetorphine and morphine might be a manifestation of differences that have been reported for these drugs at the cellular level.

  10. Stimulus characteristics affect assessment of pupil defects in amblyopia.

    Science.gov (United States)

    Law, Cristina Llerena; Siu, Matt; Modica, Patricia; Backus, Benjamin

    2015-05-01

    Amblyopes do not reliably show relative afferent pupillary defects with full-field stimulation, but amblyopia has cortical involvement; hence, stimuli that engage cortex may be able to reveal pupil defects in amblyopes. Pupillary responses were acquired with a binocular infrared pupillometer (RAPDx, Konan Medical USA, Irvine, CA) from 15 amblyopic subjects (anisometropic and small-angle strabismic) and 10 age-matched control subjects. Stimuli were a full-field white flash (330 cd/m) or a small (4 degrees) annulus at one of three contrast levels (0.3, 0.6, and 1.8) on a dim background (6.2 cd/m). Stimulus duration was 100 milliseconds, and the interstimulus duration was 2000 milliseconds. In all four stimulus conditions, the difference in percent contraction amplitude for right versus left eye stimulation was more variable across amblyopes than across control subjects. Amblyopic eyes did not show a specific deficit for the full-field flash. However, the mid-contrast (0.6) annulus stimulus revealed a deficit in the amblyopic eye, whereas the size of the deficit did not correlate with the type or depth of the amblyopia. Targets of appropriate pattern, brightness, and contrast that select for cortical contributions to the pupil response may be useful for eliciting pupil defects in amblyopic patients. Pupil analysis in this population could prove useful for diagnostic or prognostic value, for example, to determine which amblyopes will respond best to treatment.

  11. Evidence for response membership in stimulus classes by pigeons.

    Science.gov (United States)

    Urcuioli, Peter J; Jones, B Max; Lionello-DeNolf, Karen M

    2013-03-01

    Response membership in pigeons' stimulus-class formation was evaluated using associative symmetry and class expansion tests. In Experiment 1, pigeons learned hue-hue (AA) and form-form (BB) successive matching plus a modified hue-form (AB) task in which reinforcement was contingent upon a left versus right side-key response after the positive AB sequences. On subsequent BA (symmetry) probe trials, pigeons responded more often to the comparisons on the reverse of the positive than negative AB sequences and, more importantly, preferentially pecked the side key consistent with symmetry after the reversed positive sequences. In Experiment 2, the original three baseline tasks were supplemented by dot-white (CC) successive matching in which reinforcement was contingent upon a left versus right side-key response after the positive CC sequences. Class expansion was then tested by presenting nonreinforced CA and CB successive matching probes. Comparison response rates were mostly nondifferential on CA probes but were uniformly higher on CB probes that consisted of the C samples and B comparisons from the same, hypothesized class. Together, these results provide evidence that responses can become members of stimulus classes, as predicted by Urcuioli's (2008) theory of pigeons' stimulus-class formation and Sidman's (2000) theory of equivalence. © Society for the Experimental Analysis of Behavior.

  12. The Effect of Stimulus Timing on Unplanned Gait Termination.

    Science.gov (United States)

    Ohm, Kelly; Hahn, Michael E

    2016-08-01

    Gait termination can be challenging for balance-impaired populations, including lower limb amputees. As powered prosthetic ankle devices come to market, it is important to better understand gait termination timing in an unplanned situation. Timing patterns were examined in unplanned gait termination to determine a threshold for being able to terminate gait in 1 step. Time to terminate gait (TTG) was also examined, using both final heel strike and center of mass (COM) acceleration metrics. Fourteen able-bodied subjects walked over ground and terminated gait in response to a randomly-timed auditory stimulus. A lumbar-mounted accelerometer and footswitches were used to assess timing of gait termination. Subjects were able to terminate gait in 1 step if the stimulus occurred at or before 19.8% of gait cycle. Later stimulus resulted in a 2-step stop pattern. The TTG using COM acceleration was greater than when using heel strike data. Motion of the COM was not fully arrested until 162 ± 38% of gait cycle. The stabilization phase between heel strike and COM motion arrest was greater for 1-step stops (1.41 ± 0.42 s) than 2-step stops (0.96 ± 0.33 s). These findings indicate gait termination timing should be calculated using COM motion, including the stabilization phase post heel strike.

  13. High Stimulus-Related Information in Barrel Cortex Inhibitory Interneurons.

    Directory of Open Access Journals (Sweden)

    Vicente Reyes-Puerta

    2015-06-01

    Full Text Available The manner in which populations of inhibitory (INH and excitatory (EXC neocortical neurons collectively encode stimulus-related information is a fundamental, yet still unresolved question. Here we address this question by simultaneously recording with large-scale multi-electrode arrays (of up to 128 channels the activity of cell ensembles (of up to 74 neurons distributed along all layers of 3-4 neighboring cortical columns in the anesthetized adult rat somatosensory barrel cortex in vivo. Using two different whisker stimulus modalities (location and frequency we show that individual INH neurons--classified as such according to their distinct extracellular spike waveforms--discriminate better between restricted sets of stimuli (≤6 stimulus classes than EXC neurons in granular and infra-granular layers. We also demonstrate that ensembles of INH cells jointly provide as much information about such stimuli as comparable ensembles containing the ~20% most informative EXC neurons, however presenting less information redundancy - a result which was consistent when applying both theoretical information measurements and linear discriminant analysis classifiers. These results suggest that a consortium of INH neurons dominates the information conveyed to the neocortical network, thereby efficiently processing incoming sensory activity. This conclusion extends our view on the role of the inhibitory system to orchestrate cortical activity.

  14. Clinical test performance of distortion-product otoacoustic emissions using new stimulus conditions.

    Science.gov (United States)

    Johnson, Tiffany A; Neely, Stephen T; Kopun, Judy G; Dierking, Darcia M; Tan, Hongyang; Gorga, Michael P

    2010-02-01

    To determine whether new stimulus parameters, which have been shown to produce large distortion-product otoacoustic emission (DPOAE) levels in a group of normal-hearing listeners (Neely et al. 2005; Johnson et al. 2006), result in more accurate identification of auditory status and more accurate predictions of behavioral threshold than traditional stimulus conditions. DPOAE input/output (I/O) functions for eight f2 frequencies ranging from 0.7 to 8 kHz were recorded from 96 ears with normal hearing and 226 ears with sensorineural hearing losses ranging from mild to profound. The primary-level differences and primary-frequency ratios were set according to the stimulus relations developed by Johnson et al. (2006). The accuracy of the dichotomous decision task (area under the relative operating characteristic curve [AROC]) for these new stimulus conditions was evaluated as a function of L2 and was compared with previous reports in the literature where traditional stimuli were used (Stover et al. 1996). Here, traditional stimuli are defined as L1 = L2 + 10 and f2/f1 = 1.22 for all L2 and f2 values. In addition to I/O functions, DPgrams with L2 = 55-dB sound pressure level (SPL) and f2 ranging from 0.7 to 8 kHz were recorded for each subject using the traditional stimuli. This provided a direct within-subject comparison of AROC for moderate-level stimuli when the new and traditional stimuli were used. Finally, the accuracy with which DPOAE thresholds predicted behavioral thresholds was evaluated in relation to previous reports in the literature for two definitions of DPOAE threshold, one where the entire I/O function was used to make the prediction and a second where the lowest L2 producing a signal to noise ratio > or =3 dB was used. There was no evidence that the new stimuli improved the accuracy with which auditory status was identified from DPOAE responses. With both the new and traditional stimuli, moderate stimulus levels (L2 = 40- to 55-dB SPL) resulted in the

  15. Maintenance in sustainable manufacturing

    Directory of Open Access Journals (Sweden)

    Vladimir Stuchly

    2014-09-01

    Full Text Available Background: Sustainable development is about reaching a balance between economic, social, and environmental goals, as well as people's participation in the planning process in order to gain their input and support. For a company, sustainable development means adoption of such business strategy and actions that contribute to satisfying present needs of company and stakeholders, as well as simultaneous protection, maintenance and strengthening of human and environmental potential which will be needed in the future. This new approach forces manufacturing companies to change their previous management paradigms. New management paradigm should include new issues and develop innovative methods, practices and technologies striving for solving problem of shortages of resources, softening environment overload and enabling development of environment-friendly lifecycle of products. Hence, its realization requires updating existing production models as they are based on previously accepted paradigm of unlimited resources and unlimited regeneration capabilities. Maintenance plays a crucial role because of its impact on availability, reliability, quality and life cycle cost, thus it should be one of the main pillars of new business running model.  Material and methods: The following paper is a result of research on the literature and observation of practices undertaken by a company within maintenance area. Results and conclusions: The main message is that considering sustainable manufacturing requires considerable expanding range of analysis and focusing on supporting processes. Maintenance offers numerous opportunities of decreasing influence of business processes on natural environment and more efficient resources utilization. The goal of maintenance processes realizing sustainable development strategy is increased profitability of exploitation and optimization of total lifecycle cost without disturbing safety and environmental issues. 

  16. Enhanced stimulus strength improves visual cognition in aging and Alzheimer's disease.

    Science.gov (United States)

    Cronin-Golomb, Alice; Gilmore, Grover C; Neargarder, Sandy; Morrison, Sarah R; Laudate, Thomas M

    2007-10-01

    Deficits in visual cognition in Alzheimer's disease (AD) arise from neuropathological changes in higher-order association areas of the cortex and from defective input from lower-level visual processing areas. We investigated whether enhanced signal strength may lead to improvement of visual cognition in AD. We tested 35 individuals with probable AD, 35 age-matched elderly control (EC) and 58 young control (YC) adults on letter identification, word reading, picture naming, discrimination of unfamiliar faces, and pattern completion. The contrast sensitivity step-difference across an independent sample of AD and EC groups was used in calculating an image filter, from which we produced stimulus-strength conditions of low-degraded, medium-normal, and high-enhanced. Using this filter we created a hypothetical proximal-strength equivalence between AD at medium strength and EC at low strength, and between AD at high strength and EC at medium strength. For letter identification, word reading, picture naming, and face discrimination, medium strength elicited AD accuracy levels and reaction times that were similar to those of EC at low strength. On picture naming, increased strength reduced perceptual-type errors for EC and AD and random errors for AD. For word reading, high strength elicited AD accuracy levels and reaction times that were equivalent to those of EC at medium strength. We saw no effect of signal-strength manipulation on performance of pattern completion, possibly owing to the complex cognitive demands of that task or to the inadequacy of the filter for its images. The results indicate that putative AD-EC differences in cognition directly reflect contrast sensitivity differences between the groups. Enhancement of stimulus strength can ameliorate vision-based deficits and lead to improvement in some aspects of cognitive performance. These results suggest new non-pharmacological avenues to explore in the attempt to improve cognition in elderly adults and

  17. Estimation of Optimum Stimulus Amplitude for Balance Training using Electrical Stimulation of the Vestibular System

    Science.gov (United States)

    Goel, R.; Rosenberg, M. J.; De Dios, Y. E.; Cohen, H. S.; Bloomberg, J. J.; Mulavara, A. P.

    2016-01-01

    at different stimulation levels. Results from the balance task suggest that there are inter-individual differences and the minimum SVS amplitude was found to be in the range of 1 mA to 2.5 mA across subjects. SVS resulted in an average decrement of balance task performance in the range of 62%-73% across different measured variables at the minimum SVS amplitude in comparison to the control trial (no stimulus). Training using supra-threshold SVS stimulation is one of the sensory challenges used for preflight SA training designed to improve adaptability to novel gravitational environments. Inter-individual differences in response to SVS can help customize the SA training paradigms using minimal dosage required. Another application of using SVS is to simulate acute deterioration of vestibular sensory inputs in the evaluation of tests for assessing vestibular function.

  18. Life cycle analysis reveals higher agroecological benefits of organic and low-input apple production

    OpenAIRE

    Simon, Sylvaine; Brun, Laurent; Hayer, Franck; Gaillard, Gérard

    2013-01-01

    International audience; Conventional agricultural systems depend on high inputs of fertilizers and toxic pesticides that are a threat for human health and the environment. Such issues are rapidly changing agriculture in Europe. As a consequence sustainable production systems are currently developed as safer alternatives, for instance organic and low-input systems use of mechanical and biological methods versus toxic substances. However, there is a lack of knowledge on the overall impact of th...

  19. SUSTAINABLE CORPORATE AND SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    DORU CÎRNU

    2017-06-01

    Full Text Available In recent decades, the image of the international business environment has changed significantly. Studies conducted by UNCTAD shows that corporate phenomenon developments in the world economy is growing. Without claiming to present an exhaustive topic so vast we tried to capture some "facets" of sustainable development from the perspective of multinational corporations, given the expansion of these economic entities and strengthening their power in the global economy. We present more negative aspects of the actions of multinational corporations in terms of sustainable development, it is very important to know both sides of the coin, which will not only help transnational giants including release. Based on issues such as corporate social responsibility, environmental pollution and workers' rights, we sought to counter official statements. The conclusion is that these economic entities are real forces that can not be ignored in today's world and the obvious problem of sustainable development can not be addressed independently of the phenomenon, context we also identified some possible solutions to conflict of corporations and essence of the concept of sustainable development.

  20. MANFAAT STIMULUS VERTEBRA CERVIKALIS KE 5-6 DAN STIMULUS OTOT RECTUS ABDOMINIS TERHADAP PERUBAHAN TFU IBU POST PARTUM PER VAGINAM

    Directory of Open Access Journals (Sweden)

    Suryanti Suryanti

    2017-02-01

    Full Text Available Latar Belakang : Involusi uterus merupakan proses normal pada masa nifas dan dimulai segera setelah plasenta lahir akibat kontraksi otot-otot polos uterus. Stimulus adalah perangsang organism tubuh atau reseptor lain untuk menjadi aktif. Pemberian stimulus Vertebra Cervikal dapat merangsang hipofisis anterior dan posterior untuk mengeluarkan hormon oksitosin. Hormon oksitosin akan memicu kontraksi otot polos pada uterus. Tujuan : Penelitian ini bertujuan untuk manfaat stimulus vertebra cervikalis ke 5-6 dan stimulus otot rectus abdominis terhadap perubahan tfu ibu post partum pervaginam. Metode: Populasi dan sampel dalam penelitian ini adalah ibu postpartum pervaginam di Ruang Nifas RSUD Dr. Soeselo Slawi. penelitian ini menggunakan t-test of relate. Hasil : Dalam uji hipotesis didapatkan t hitung ? t table (10.863 ? 1.980, maka dapat disimpulkan Ho ditolak dan Ha diterima. Kesimpulan : Artinya terdapat manfaat stimulus vertebra cervikalis ke 5-6 dan stimulus otot rectus abdominis terhadap perubahan tinggi fundus uteri ibu postpartum pervaginam.

  1. Sustainable Consumption

    DEFF Research Database (Denmark)

    Røpke, Inge

    2015-01-01

    in wider social, economic and technological frameworks is emphasised. In particular, the chapter is inspired by practice theory and transition theory. First, various trends in consumption are outlined to highlight some of the challenges for sustainability transitions. Then, it is discussed how consumption...... patterns are shaped over time and what should be considered in sustainability strategies. While discussions on consumption often take their point of departure in the perspective of the individual and then zoom to the wider context, the present approach is the opposite. The outline starts with the basic...... biophysical, distributional and economic conditions for high consumption in rich countries and then zooms in on the coevolution of provision systems and consumption, and how consumption is shaped by practices and projects in everyday life. Furthermore, the paper discusses whether and how transition...

  2. Sustainable Buildings

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Elle, Morten

    The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems that ...... that need urgent action. The built environment is an obvious area to put effort into because of the large and cost-effective energy saving potential and potential for Renewable Energy-based supply systems for buildings.......The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems...

  3. Stimulus-Seeking, Extraversion, and Neuroticism in Regular, Occasional, and Non-Exercisers.

    Science.gov (United States)

    Burgess, Sharon S.; Pargman, David

    To test the hypothesis that stimulus-seeking and extraversion underlie "exercise addiction" and sport involvement, the relationships among stimulus-seeking, extraversion, and exercise frequency were examined in ninety males matched on age and educational level. The Stimulus Variation Seeking Scale, Sensation-Seeking Scale (SSS) and…

  4. Distortions of temporal integration and perceived order caused by the interplay between stimulus contrast and duration

    NARCIS (Netherlands)

    Akyürek, Elkan G.; de Jong, Ritske

    2017-01-01

    Stimulus contrast and duration effects on visual temporal integration and order judgment were examined in a unified paradigm. Stimulus onset asynchrony was governed by the duration of the first stimulus in Experiment 1, and by the interstimulus interval in Experiment 2. In Experiment 1, integration

  5. Additive Effects of Stimulus Quality and Word Frequency on Eye Movements during Chinese Reading

    Science.gov (United States)

    Liu, Pingping; Li, Xingshan; Han, Buxin

    2015-01-01

    Eye movements of Chinese readers were recorded for sentences in which high- and low-frequency target words were presented normally or with reduced stimulus quality in two experiments. We found stimulus quality and word frequency produced strong additive effects on fixation durations for target words. The results demonstrate that stimulus quality…

  6. Frontal networks for learning and executing arbitrary stimulus-response associations.

    Science.gov (United States)

    Boettiger, Charlotte A; D'Esposito, Mark

    2005-03-09

    Flexible rule learning, a behavior with obvious adaptive value, is known to depend on an intact prefrontal cortex (PFC). One simple, yet powerful, form of such learning consists of forming arbitrary stimulus-response (S-R) associations. A variety of evidence from monkey and human studies suggests that the PFC plays an important role in both forming new S-R associations and in using learned rules to select the contextually appropriate response to a particular stimulus cue. Although monkey lesion studies more strongly implicate the ventrolateral PFC (vlPFC) in S-R learning, clinical data and neurophysiology studies have implicated both the vlPFC and the dorsolateral region (dlPFC) in associative rule learning. Previous human imaging studies of S-R learning tasks, however, have not demonstrated involvement of the dlPFC. This may be because of the design of previous imaging studies, which used few stimuli and used explicitly stated one-to-one S-R mapping rules that were usually practiced before scanning. Humans learn these rules very quickly, limiting the ability of imaging techniques to capture activity related to rule acquisition. To address these issues, we performed functional magnetic resonance imaging while subjects learned by trial and error to associate sets of abstract visual stimuli with arbitrary manual responses. Successful learning of this task required discernment of a categorical type of S-R rule in a block design expected to yield sustained rule representation. Our results show that distinct components of the dorsolateral, ventrolateral, and anterior PFC, lateral premotor cortex, supplementary motor area, and the striatum are involved in learning versus executing categorical S-R rules.

  7. Load-Dependent Increases in Delay-Period Alpha-Band Power Track the Gating of Task-Irrelevant Inputs to Working Memory

    Science.gov (United States)

    Heinz, Andrew J.; Johnson, Jeffrey S.

    2017-01-01

    Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band power (ABP) during the delay period of verbal and visual working memory (VWM) tasks. There have been various proposals regarding the functional significance of such increases, including the inhibition of task-irrelevant cortical areas as well as the active retention of information in VWM. The present study examines the role of delay-period ABP in mediating the effects of interference arising from on-going visual processing during a concurrent VWM task. Specifically, we reasoned that, if set-size dependent increases in ABP represent the gating out of on-going task-irrelevant visual inputs, they should be predictive with respect to some modulation in visual evoked potentials resulting from a task-irrelevant delay period probe stimulus. In order to investigate this possibility, we recorded the electroencephalogram while subjects performed a change detection task requiring the retention of two or four novel shapes. On a portion of trials, a novel, task-irrelevant bilateral checkerboard probe was presented mid-way through the delay. Analyses focused on examining correlations between set-size dependent increases in ABP and changes in the magnitude of the P1, N1 and P3a components of the probe-evoked response and how such increases might be related to behavior. Results revealed that increased delay-period ABP was associated with changes in the amplitude of the N1 and P3a event-related potential (ERP) components, and with load-dependent changes in capacity when the probe was presented during the delay. We conclude that load-dependent increases in ABP likely play a role in supporting short-term retention by gating task-irrelevant sensory inputs and suppressing potential sources of disruptive interference. PMID:28555099

  8. Load-Dependent Increases in Delay-Period Alpha-Band Power Track the Gating of Task-Irrelevant Inputs to Working Memory

    Directory of Open Access Journals (Sweden)

    Andrew J. Heinz

    2017-05-01

    Full Text Available Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band power (ABP during the delay period of verbal and visual working memory (VWM tasks. There have been various proposals regarding the functional significance of such increases, including the inhibition of task-irrelevant cortical areas as well as the active retention of information in VWM. The present study examines the role of delay-period ABP in mediating the effects of interference arising from on-going visual processing during a concurrent VWM task. Specifically, we reasoned that, if set-size dependent increases in ABP represent the gating out of on-going task-irrelevant visual inputs, they should be predictive with respect to some modulation in visual evoked potentials resulting from a task-irrelevant delay period probe stimulus. In order to investigate this possibility, we recorded the electroencephalogram while subjects performed a change detection task requiring the retention of two or four novel shapes. On a portion of trials, a novel, task-irrelevant bilateral checkerboard probe was presented mid-way through the delay. Analyses focused on examining correlations between set-size dependent increases in ABP and changes in the magnitude of the P1, N1 and P3a components of the probe-evoked response and how such increases might be related to behavior. Results revealed that increased delay-period ABP was associated with changes in the amplitude of the N1 and P3a event-related potential (ERP components, and with load-dependent changes in capacity when the probe was presented during the delay. We conclude that load-dependent increases in ABP likely play a role in supporting short-term retention by gating task-irrelevant sensory inputs and suppressing potential sources of disruptive interference.

  9. Visual Working Memory Enhances the Neural Response to Matching Visual Input.

    Science.gov (United States)

    Gayet, Surya; Guggenmos, Matthias; Christophel, Thomas B; Haynes, John-Dylan; Paffen, Chris L E; Van der Stigchel, Stefan; Sterzer, Philipp

    2017-07-12

    Visual working memory (VWM) is used to maintain visual information available for subsequent goal-directed behavior. The content of VWM has been shown to affect the behavioral response to concurrent visual input, suggesting that visual representations originating from VWM and from sensory input draw upon a shared neural substrate (i.e., a sensory recruitment stance on VWM storage). Here, we hypothesized that visual information maintained in VWM would enhance the neural response to concurrent visual input that matches the content of VWM. To test this hypothesis, we measured fMRI BOLD responses to task-irrelevant stimuli acquired from 15 human participants (three males) performing a concurrent delayed match-to-sample task. In this task, observers were sequentially presented with two shape stimuli and a retro-cue indicating which of the two shapes should be memorized for subsequent recognition. During the retention interval, a task-irrelevant shape (the probe) was briefly presented in the peripheral visual field, which could either match or mismatch the shape category of the memorized stimulus. We show that this probe stimulus elicited a stronger BOLD response, and allowed for increased shape-classification performance, when it matched rather than mismatched the concurrently memorized content, despite identical visual stimulation. Our results demonstrate that VWM enhances the neural response to concurrent visual input in a content-specific way. This finding is consistent with the view that neural populations involved in sensory processing are recruited for VWM storage, and it provides a common explanation for a plethora of behavioral studies in which VWM-matching visual input elicits a stronger behavioral and perceptual response. SIGNIFICANCE STATEMENT Humans heavily rely on visual information to interact with their environment and frequently must memorize such information for later use. Visual working memory allows for maintaining such visual information in the mind

  10. Stimulus-specific expression of inducible transcription factors in identified oxytocin neurones.

    Science.gov (United States)

    Luckman, S M

    1995-01-01

    The activation of the magnocellular oxytocin system by different physiological stimuli will require specific genomic responses that may or may not reflect the electrical and short-term secretory activity of the neurones. One of the main determinants of synthetic activity is the rate of transcription and this can be altered acutely by the action of inducible transcription factors (iTFs). Having shown that the expression of two iTFs, the protein products of the c-fos and c-jun genes, does not correlate directly to the electrical activity of magnocellular neurones (Luckman et al., 1994) the expression of leucine zipper iTF mRNAs was measured following different stimuli using combined radioactive and non-radioactive in situ hybridization. Stimuli that are dependent on brainstem afferents such as parturition and systemic injection of cholecystokinin caused co-induction of c-fos and c-jun in oxytocin neurones. Mild osmotic stimulation, a stimulus dependent on forebrain afferents, induced c-fos, fos B and jun B, but inhibited c-jun. Similar patterns of leucine zipper iTF expression have been noted in cultured cells following activation of protein kinases C and A, respectively. Input from the brainstem appears to be mediated, at least in part, by noradrenaline acting on alpha(1)-adrenoceptors. While the forebrain inputs are not well characterised they do appear to include a glutaminergic component that may activate a variety of receptors. Interestingly, another member of the leucine zipper family known to be induced by protein kinase A, inducible cAMP early repressor (ICER), that was previously thought to be restricted to the pineal gland, was expressed in magnocellular neurones following osmotic stimulation but not parturition. Furthermore, the differential expression of iTFs is not limited to this family. Osmotic stimulation influences c-fos, but it also causes the expression of NGFI-A and NGFI-B, members of the zinc finger family of iTFs. By contrast, an acute suckling

  11. Greener and Sustainable Trends in Synthesis of Organics and Nanomaterials

    Science.gov (United States)

    Trends in greener and sustainable process development during the past 25 years are abridged involving the use of alternate energy inputs (mechanochemistry, ultrasound- or microwave irradiation), photochemistry, and greener reaction media as applied to synthesis of organics and na...

  12. Procedure for developing biological input for the design, location, or modification of water-intake structures

    Energy Technology Data Exchange (ETDEWEB)

    Neitzel, D.A.; McKenzie, D.H.

    1981-12-01

    To minimize adverse impact on aquatic ecosystems resulting from the operation of water intake structures, design engineers must have relevant information on the behavior, physiology and ecology of local fish and shellfish. Identification of stimulus/response relationships and the environmental factors that influence them is the first step in incorporating biological information in the design, location or modification of water intake structures. A procedure is presented in this document for providing biological input to engineers who are designing, locating or modifying a water intake structure. The authors discuss sources of stimuli at water intakes, historical approaches in assessing potential/actual impact and review biological information needed for intake design.

  13. Motor learning reduces eye movement variability through reweighting of sensory inputs

    Science.gov (United States)

    Guo, Cong C.; Raymond, Jennifer L.

    2010-01-01

    Motor learning can improve both the accuracy and precision of motor performance. We analyzed changes in the average trajectory and the variability of smooth eye movements during motor learning in rhesus monkeys. Training with a compound visual-vestibular stimulus could reduce the variability of the eye movement responses without altering the average responses. This improvement of eye movement precision was achieved by shifting the reliance of the movements from a more variable, visual signaling pathway to a less variable, vestibular signaling pathway. Thus, cerebellum-dependent motor learning can improve the precision of movements by reweighting sensory inputs with different variability. PMID:21123570

  14. Input Method "Five Strokes": Advantages and Problems

    Directory of Open Access Journals (Sweden)

    Mateja PETROVČIČ

    2014-03-01

    Since the Five Stroke input method is easily accessible, simple to master and is not pronunciation-based, we would expect that the students will use it to input unknown characters. The survey comprises students of Japanology and Sinology at Department of Asian and African Studies, takes in consideration the grade of the respondent and therefore his/her knowledge of characters. This paper also discusses the impact of typeface to the accuracy of the input.

  15. Effects of stimulus-driven synchronization on sensory perception

    Directory of Open Access Journals (Sweden)

    Holden Jameson K

    2007-12-01

    Full Text Available Abstract Background A subject's ability to differentiate the loci of two points on the skin depends on the stimulus-evoked pericolumnar lateral inhibitory interactions which increase the spatial contrast between regions of SI cortex that are activated by stimulus-evoked afferent drive. Nevertheless, there is very little known about the impact that neuronal interactions – such as those evoked by mechanical skin stimuli that project to and coordinate synchronized activity in adjacent and/or near-adjacent cortical columns – could have on sensory information processing. Methods The temporal order judgment (TOJ and temporal discriminative threshold (TDT of 20 healthy adult subjects were assessed both in the absence and presence of concurrent conditions of tactile stimulation. These measures were obtained across a number of paired sites – two unilateral and one bilateral – and several conditions of adapting stimuli were delivered both prior to and concurrently with the TOJ and TDT tasks. The pairs of conditioning stimuli were synchronized and periodic, synchronized and non-periodic, or asynchronous and non-periodic. Results In the absence of any additional stimuli, TOJ and TDT results obtained from the study were comparable across a number of pairs of stimulus sites – unilateral as well as bilateral. In the presence of a 25 Hz conditioning sinusoidal stimulus which was delivered both before, concurrently and after the TOJ task, there was a significant change in the TOJ measured when the two stimuli were located unilaterally on digits 2 and 3. However, in the presence of the same 25 Hz conditioning stimulus, the TOJ obtained when the two stimuli were delivered bilaterally was not impacted. TDT measures were not impacted to the same degree by the concurrent stimuli that were delivered to the unilateral or bilateral stimulus sites. This led to the speculation that the impact that the conditioning stimuli – which were sinusoidal, periodic and

  16. SUSTAINABLE CHEMISTRY FOR SUSTAINABLE INDUSTRY

    Directory of Open Access Journals (Sweden)

    G. Rizzuto

    2015-01-01

    Full Text Available Foundry Alfe Chem is an industrial reality working in the field of lubrication and chemical auxiliaries for industrial processes, which falls within the framework of the emerging and increasingly important «green chemistry». The goal of the company is to develop products that are more environmentally friendly by using raw materials from renewable sources; specifically, Foundry Alfe Chem has a program of self-sustainability that contemplates, for the foreseeable future, the direct production of renewable raw materials. The company has developed a new dedicated product line, Olitema, whose purpose is to offer highly technological solutions with complete environmental sustainability. In this context, Foundry Alfe CHEM has created a new product which represents a breakthrough in the class of HFC hydraulic fluids: Ecosafe Plus is a biodegradable fire-resistant hydraulic fluid with high engineering and technological performances, high environmental sustainability and the best security guarantees in workplaces. Its formulation is glycols-free, and it allows for easier disposal of the exhausted fluid, compared to a traditional water/ glycol-based HFC hydraulic fluid. For what concern the technological properties, Ecosafe Plus has been tested by accredited laboratories with tribological trials (4 Ball wear test ASTM D 4172, Ball on disc test ASTM 6425, Brugger test DIN 51347, Vickers test ASTM D 2882, with elastomer compatibility test (ASTM D 471 and biodegradability test (OECD 310 F.

  17. Voice attractiveness: influence of stimulus duration and type.

    Science.gov (United States)

    Ferdenzi, C; Patel, S; Mehu-Blantar, I; Khidasheli, M; Sander, D; Delplanque, S

    2013-06-01

    Voice attractiveness is a relatively new area of research. Some aspects of the methodology used in this domain deserve particular attention. Especially, the duration of voice samples is often neglected as a factor and happens to be manipulated without the perceptual consequences of these manipulations being known. Moreover, the type of voice stimulus varies from a single vowel to complex sentences. The aim of this experiment was to investigate the extent to which stimulus duration (nonmanipulated vs. normalized) and type (vowel vs. word) influence perceived voice attractiveness. Twenty-seven male and female raters made attractiveness judgments of 30 male and female voice samples. Voice samples included a single vowel /a/, a three-vowel series /i a o/, and the French word "bonjour" (i.e., "hello"). These samples were presented in three conditions: nonmanipulated, shortened, and lengthened duration. Duration manipulation was performed using the pitch synchronous overlap and add (PSOLA) algorithm implemented in Praat. Results for the effect of stimulus type showed that word length samples were more attractive to the opposite sex than vowels. Results for the effect of duration showed that the nonmanipulated sound sample duration was not predictive of perceived attractiveness. Duration manipulation, on the other hand, altered perceived attractiveness for the lengthening condition. In particular, there was a linear decrease in attractiveness as a function of modification percentage (especially for the word, as compared with the vowels). Recommendations for voice sample normalization with the PSOLA algorithm are thus to prefer shortening over lengthening and, if not possible, to limit the extent of duration manipulation-for example, by normalizing to the mean sample duration.

  18. Input characterization of a shock test strructure.

    Energy Technology Data Exchange (ETDEWEB)

    Hylok, J. E. (Jeffrey E.); Groethe, M. A.; Maupin, R. D. (Ryan D.)

    2004-01-01

    Often in experimental work, measuring input forces and pressures is a difficult and sometimes impossible task. For one particular shock test article, its input sensitivity required a detailed measurement of the pressure input. This paper discusses the use of a surrogate mass mock test article to measure spatial and temporal variations of the shock input within and between experiments. Also discussed will be the challenges and solutions in making some of the high speed transient measurements. The current input characterization work appears as part of the second phase in an extensive model validation project. During the first phase, the system under analysis displayed sensitivities to the shock input's qualitative and quantitative (magnitude) characteristics. However, multiple shortcomings existed in the characterization of the input. First, the experimental measurements of the input were made on a significantly simplified structure only, and the spatial fidelity of the measurements was minimal. Second, the sensors used for the pressure measurement contained known errors that could not be fully quantified. Finally, the measurements examined only one input pressure path (from contact with the energetic material). Airblast levels from the energetic materials were unknown. The result was a large discrepancy between the energy content in the analysis and experiments.

  19. The poverty of the stimulus: Quine and Wittgenstein

    Directory of Open Access Journals (Sweden)

    O’Sullivan Michael

    2014-01-01

    Full Text Available Quine and Wittgenstein were dominant figures in philosophy in the middle of the twentieth century. Many readers, like Quine himself, have felt that there are deep similarities between the two thinkers, though those similarities are difficult to articulate. I argue that they share the project of understanding the meaning of utterances by reference to the environment of the speaker, though they understand that environment in radically different ways. In particular, Quine has a much thinner conception of the environment than does Wittgenstein. For Quine, the stimulus is impoverished in a way that it is not for Wittgenstein. I also argue that they share a certain deflationary approach to ontology.

  20. Validity of electrical stimulus magnitude matching in chronic pain

    DEFF Research Database (Denmark)

    Persson, Ann L; Westermark, Sofia; Merrick, Daniel

    2009-01-01

    OBJECTIVE: To examine the validity of the PainMatcher in chronic pain. DESIGN: Comparison of parallel pain estimates from visual analogue scales with electrical stimulus magnitude matching. PATIENTS: Thirty-one patients with chronic musculoskeletal pain. METHODS: Twice a day ongoing pain was rated...... range of the instrument, the PainMatcher readings utilized only a small part of the instrument range and, importantly, had little or no relation to the visual analogue scale estimates. The validity of the PainMatcher procedure is doubtful....

  1. Brief-stimulus presentations on multiform tandem schedules

    OpenAIRE

    Reed, Phil

    1994-01-01

    Three experiments examined the influence of a brief stimulus (a light) on the behavior of food-deprived rats whose lever pressing on tandem schedules comprising components of different schedule types resulted in food presentation. In Experiment 1, either a tandem variable-ratio variable-interval or a tandem variable-interval variable-ratio schedule was used. The variable-interval requirement in the tandem variable-ratio variable-interval schedule was yoked to the time taken to complete the va...

  2. Sustainable Procurement

    DEFF Research Database (Denmark)

    Telles, Pedro; Ølykke, Grith Skovgaard

    2017-01-01

    and within it how sustainable requirements have increased the level of compliance required, particularly regulatory compliance. Compliance was already present in previous EU public procurement frameworks, but its extent on Directive 2014/24/EU leads the authors to consider the current legal framework...... as subject to substantial regulatory compliance obligations external to the process of procurement. In short, procurement has been transformed in a way to enforce regulatory obligations that are not intrinsic to the process of buying. This leads to the conclusion that questions such as the cost and trade...

  3. Learning structure of sensory inputs with synaptic plasticity leads to interference.

    Science.gov (United States)

    Chrol-Cannon, Joseph; Jin, Yaochu

    2015-01-01

    Synaptic plasticity is often explored as a form of unsupervised adaptation in cortical microcircuits to learn the structure of complex sensory inputs and thereby improve performance of classification and prediction. The question of whether the specific structure of the input patterns is encoded in the structure of neural networks has been largely neglected. Existing studies that have analyzed input-specific structural adaptation have used simplified, synthetic inputs in contrast to complex and noisy patterns found in real-world sensory data. In this work, input-specific structural changes are analyzed for three empirically derived models of plasticity applied to three temporal sensory classification tasks that include complex, real-world visual and auditory data. Two forms of spike-timing dependent plasticity (STDP) and the Bienenstock-Cooper-Munro (BCM) plasticity rule are used to adapt the recurrent network structure during the training process before performance is tested on the pattern recognition tasks. It is shown that synaptic adaptation is highly sensitive to specific classes of input pattern. However, plasticity does not improve the performance on sensory pattern recognition tasks, partly due to synaptic interference between consecutively presented input samples. The changes in synaptic strength produced by one stimulus are reversed by the presentation of another, thus largely preventing input-specific synaptic changes from being retained in the structure of the network. To solve the problem of interference, we suggest that models of plasticity be extended to restrict neural activity and synaptic modification to a subset of the neural circuit, which is increasingly found to be the case in experimental neuroscience.

  4. Intention-based and stimulus-based mechanisms in action selection.

    Science.gov (United States)

    Waszak, Florian; Wascher, Edmund; Keller, Peter; Koch, Iring; Aschersleben, Gisa; Rosenbaum, David A; Prinz, Wolfgang

    2005-04-01

    Human actions can be classified as being either more stimulus-based or more intention-based. According to the ideomotor framework of action control, intention-based actions primarily refer to anticipated action effects (in other words response-stimulus [R-S] bindings), whereas stimulus-based actions are commonly assumed to be more strongly determined by stimulus-response [S-R] bindings. We explored differences in the functional signatures of both modes of action control in a temporal bisection task. Participants either performed a choice response by pressing one out of two keys in response to a preceding stimulus (stimulus-based action), or pressed one out of two keys to produce the next stimulus (intention-based action). In line with the ideomotor framework, we found intention-based actions to be shifted in time towards their anticipated effects (the next stimulus), whereas stimulus-based actions were shifted towards their preceding stimulus. Event-related potentials (ERPs) in the EEG revealed marked differences in action preparation for the two tasks. The data as a whole provide converging evidence for functional differences in the selection of motor actions as a function of their triggering conditions, and support the notion of two different modes of action selection, one being exogenous or mainly stimulus-driven, the other being endogenous or mainly intention-driven.

  5. Fractal gait patterns are retained after entrainment to a fractal stimulus.

    Science.gov (United States)

    Rhea, Christopher K; Kiefer, Adam W; Wittstein, Matthew W; Leonard, Kelsey B; MacPherson, Ryan P; Wright, W Geoffrey; Haran, F Jay

    2014-01-01

    Previous work has shown that fractal patterns in gait can be altered by entraining to a fractal stimulus. However, little is understood about how long those patterns are retained or which factors may influence stronger entrainment or retention. In experiment one, participants walked on a treadmill for 45 continuous minutes, which was separated into three phases. The first 15 minutes (pre-synchronization phase) consisted of walking without a fractal stimulus, the second 15 minutes consisted of walking while entraining to a fractal visual stimulus (synchronization phase), and the last 15 minutes (post-synchronization phase) consisted of walking without the stimulus to determine if the patterns adopted from the stimulus were retained. Fractal gait patterns were strengthened during the synchronization phase and were retained in the post-synchronization phase. In experiment two, similar methods were used to compare a continuous fractal stimulus to a discrete fractal stimulus to determine which stimulus type led to more persistent fractal gait patterns in the synchronization and post-synchronization (i.e., retention) phases. Both stimulus types led to equally persistent patterns in the synchronization phase, but only the discrete fractal stimulus led to retention of the patterns. The results add to the growing body of literature showing that fractal gait patterns can be manipulated in a predictable manner. Further, our results add to the literature by showing that the newly adopted gait patterns are retained for up to 15 minutes after entrainment and showed that a discrete visual stimulus is a better method to influence retention.

  6. Sustainable consumption and marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2016-01-01

    Sustainable development in global food markets is hindered by the discrepancy between positive consumer attitudes towards sustainable development or sustainability and the lack of corresponding sustainable consumption by a majority of consumers. Apparently for many (light user) consumers the

  7. Bilinearity in spatiotemporal integration of synaptic inputs.

    Directory of Open Access Journals (Sweden)

    Songting Li

    2014-12-01

    Full Text Available Neurons process information via integration of synaptic inputs from dendrites. Many experimental results demonstrate dendritic integration could be highly nonlinear, yet few theoretical analyses have been performed to obtain a precise quantitative characterization analytically. Based on asymptotic analysis of a two-compartment passive cable model, given a pair of time-dependent synaptic conductance inputs, we derive a bilinear spatiotemporal dendritic integration rule. The summed somatic potential can be well approximated by the linear summation of the two postsynaptic potentials elicited separately, plus a third additional bilinear term proportional to their product with a proportionality coefficient [Formula: see text]. The rule is valid for a pair of synaptic inputs of all types, including excitation-inhibition, excitation-excitation, and inhibition-inhibition. In addition, the rule is valid during the whole dendritic integration process for a pair of synaptic inputs with arbitrary input time differences and input locations. The coefficient [Formula: see text] is demonstrated to be nearly independent of the input strengths but is dependent on input times and input locations. This rule is then verified through simulation of a realistic pyramidal neuron model and in electrophysiological experiments of rat hippocampal CA1 neurons. The rule is further generalized to describe the spatiotemporal dendritic integration of multiple excitatory and inhibitory synaptic inputs. The integration of multiple inputs can be decomposed into the sum of all possible pairwise integration, where each paired integration obeys the bilinear rule. This decomposition leads to a graph representation of dendritic integration, which can be viewed as functionally sparse.

  8. Flavor Identification and Intensity: Effects of Stimulus Context

    Science.gov (United States)

    Hallowell, Emily S.; Parikh, Roshan; Veldhuizen, Maria G.

    2016-01-01

    Two experiments presented oral mixtures containing different proportions of the gustatory flavorant sucrose and an olfactory flavorant, either citral (Experiment 1) or lemon (Experiment 2). In 4 different sessions of each experiment, subjects identified each mixture as “mostly sugar” or “mostly citrus/lemon” or rated the perceived intensities of the sweet and citrus components. Different sessions also presented the mixtures in different contexts, with mixtures containing relatively high concentrations of sucrose or citral/lemon presented more often (skew sucrose or skew citral/lemon). As expected, in both experiments, varying stimulus context affected both identification and perceived intensity: Skewing to sucrose versus citral/lemon decreased the probability of identifying the stimuli as “mostly sugar” and reduced the ratings of sweet intensity relative to citrus intensity. Across both contextual conditions of both experiments, flavor identification associated closely with the ratio of the perceived sweet and citrus intensities. The results accord with a model, extrapolated from signal-detection theory, in which sensory events are represented as multisensory–multidimensional distributions in perceptual space. Changing stimulus context can shift the locations of the distributions relative to response criteria, Decision rules guide judgments based on both sensory events and criteria, these rules not necessarily being identical in tasks of identification and intensity rating. PMID:26830499

  9. The Grand Canyon midair collision. A stimulus for change.

    Science.gov (United States)

    Murphy, G K

    1990-06-01

    Commercial aviation in the United States developed rapidly from a nucleus of pilots who returned from World War I, barnstormed and flew primitive airmail routes, and were hired by the new commerical airlines of the 1930s. The death of U.S. Senator Bronson Cutting in a 1935 crash was an important stimulus to improved governmental regulation of civil aviation. The air traffic control system, primitive until and throughout World War II, was soon proven to be inadequate for postwar demands. The midair collision of two large airliners over the Grand Canyon in June 1956 that killed the 128 persons on board was itself a strong stimulus for serious efforts, particularly in improving air traffic control systems. This and many other difficult problems in aviation safety have been addressed in the subsequent 33 years, some with success, although it has not always been immediate, and with major accidents still occurring. Commercial air travel is safe and widely accepted, however, and there is promise for additional important advances here.

  10. Fetal brain activity and hemodynamic response to a vibroacoustic stimulus.

    Science.gov (United States)

    Fulford, Jonathan; Vadeyar, Shantala H; Dodampahala, Sanani H; Ong, Stephen; Moore, Rachel J; Baker, Philip N; James, David K; Gowland, Penny

    2004-06-01

    Previous studies have demonstrated the practicality of using functional magnetic resonance imaging (fMRI) techniques to assess fetal brain activity. The purpose of this study was to compare the fetal hemodynamic response to that of the adult. Seventeen pregnant subjects, all of whom were at more than 36 weeks gestation were scanned while the fetus was exposed to a vibroacoustic stimulus. Thirteen adult subjects were scanned with an equivalent acoustic stimulus. Of the fetal subjects, two could not be analyzed due to technical problems, eight did not show significant activation, and seven showed significant activation. In all cases, activation was localized within the temporal region. Measures of fetal hemodynamic responses revealed an average time to peak (ttp) of 7.36 +/- 0.94 sec and an average percentage change of 2.67 +/- 0.93%. In contrast, activation was detected in 5 of 13 adults with an average ttp of 6.54 +/- 0.54 sec and an average percentage change of 1.02 +/- 0.40%. The measurement of changes in the fetal hemodynamic response may be important in assessing compromised pregnancies. Copyright 2004 Wiley-Liss, Inc.

  11. Adduction of untested derived stimulus relations depends on environmental complexity.

    Science.gov (United States)

    Rippy, Sterling M; Doughty, Adam H

    2017-10-01

    The present research assessed adduction involving derived stimulus relations as a function of environmental complexity. In Group CA, four college students were trained with arbitrary-matching-to-sample discriminations that could have established four, 3-member stimulus classes. In Group EA, four other students were trained with discriminations that could have established four, 5-member classes. Neither group received derived-relations testing; instead, adduction was assessed immediately after the baseline discriminations were learned. The adduction assessment required participants to derive the untested CA (Group CA) or EA (Group EA) equivalence relations and combine them with their already learned math skills. All participants in Group CA showed above 90% accuracy during the adduction assessment, whereas only one of four Group EA participants responded in that manner. These results extend adduction to untested equivalence relations and clarify the environmental conditions under which such adduction is less likely to occur (i.e., with larger relational networks). Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Stimulus Novelty Energizes Actions in the Absence of Explicit Reward.

    Directory of Open Access Journals (Sweden)

    Raphael Koster

    Full Text Available Novelty seeking has been tied to impulsive choice and biased value based choice. It has been postulated that novel stimuli should trigger more vigorous approach and exploration. However, it is unclear whether stimulus novelty can enhance simple motor actions in the absence of explicit reward, a necessary condition for energizing approach and exploration in an entirely unfamiliar situation. In this study human subjects were cued to omit or perform actions in form of button presses by novel or familiar images. We found that subjects' motor actions were faster when cued by a novel compared to a familiar image. This facilitation by novelty was strongest when the delay between cue and action was short, consistent with a link between novelty and impulsive choices. The facilitation of reaction times by novelty was correlated across subjects with trait novelty seeking as measured in the Tridimensional Personality Questionnaire. However, this li between high novelty-seeking and action facilitation was driven by trials with a long delay between cue and action. This prolonged time window of energization following novelty could hint at a mechanistic underpinning of enhanced vigour for approach and exploration frequently postulated for novelty seeking humans. In conclusion, we show that stimulus novelty enhances the speed of a cued motor action. We suggest this is likely to reflect an adaptation to changing environments but may also provide a source of maladaptive choice and impulsive behaviour.

  13. Inhibition of eye blinking reveals subjective perceptions of stimulus salience.

    Science.gov (United States)

    Shultz, Sarah; Klin, Ami; Jones, Warren

    2011-12-27

    Spontaneous eye blinking serves a critical physiological function, but it also interrupts incoming visual information. This tradeoff suggests that the inhibition of eye blinks might constitute an adaptive reaction to minimize the loss of visual information, particularly information that a viewer perceives to be important. To test this hypothesis, we examined whether the timing of blink inhibition, during natural viewing, is modulated between as well as within tasks, and also whether the timing of blink inhibition varies as a function of viewer engagement and stimulus event type. While viewing video scenes, we measured the timing of blinks and blink inhibition, as well as visual scanning, in a group of typical two-year-olds, and in a group of two-year-olds known for attenuated reactivity to affective stimuli: toddlers with Autism Spectrum Disorders (ASD). Although both groups dynamically adjusted the timing of their blink inhibition at levels greater than expected by chance, they inhibited their blinking and shifted visual fixation differentially with respect to salient onscreen events. Moreover, typical toddlers inhibited their blinking earlier than toddlers with ASD, indicating active anticipation of the unfolding of those events. These findings indicate that measures of blink inhibition can serve as temporally precise markers of perceived stimulus salience and are useful quantifiers of atypical processing of social affective signals in toddlers with ASD.

  14. Stimulus-Specific Transcriptional Regulation Within the p53 Network

    Science.gov (United States)

    Donner, Aaron Joseph; Hoover, Jennifer Michelle; Szostek, Stephanie Aspen; Espinosa, Joaquín Maximiliano

    2010-01-01

    The p53 transcriptional network is composed of hundreds of effector genes involved in varied stress-response pathways, including cell cycle arrest and apoptosis. It is not clear how distinct p53 target genes are differentially activated to trigger stress-specific biological responses. We analyzed the p53 transcriptional program upon activation by two DNA-damaging agents, UVC and doxorubicin, versus the non-genotoxic molecule Nutlin-3. In colorectal cancer cells, UVC triggers apoptosis, doxorubicin induces transient cell cycle arrest followed by apoptosis, and Nutlin-3 leads to cell cycle arrest with no significant apoptosis. Quantitative gene expression analysis allowed us to group p53 target genes into three main classes according to their activation profiles in each scenario. The CDK-inhibitor p21 was classified as a Class I gene, being significantly activated under cell cycle arrest conditions (i.e., doxorubicin and Nutlin-3) but not during UVC-induced apoptosis. Chromatin immunoprecipitation analysis of the p21 locus indicates that the level of p53-dependent transcription is determined by the effects of stimulus-specific transcriptional coregulators acting downstream of p53 binding and histone acetylation. In particular, our analysis indicates that the subunits of the CDK-module of the human Mediator complex function as stimulus-specific positive coregulators of p21 transcription. PMID:17957141

  15. Effects of ayahuasca on binocular rivalry with dichoptic stimulus alternation.

    Science.gov (United States)

    Frecska, E; White, K D; Luna, L E

    2004-04-01

    During binocular rivalry, two incompatible images are presented to each eye and these monocular stimuli compete for perceptual dominance, with one pattern temporarily suppressed from awareness. One variant of stimulus presentation in binocular rivalry experiments is dichoptic stimulus alternation (DSA), when stimuli are applied to the eyes in rapid reversals. There is preliminary report that in contrast with healthy controls, schizophrenic patients can maintain binocular rivalry even at very high DSA rates. The study was undertaken to investigate whether binocular rivalry survives high rates of DSA induced by the South American hallucinogenic beverage ayahuasca. Ten individuals who were participating in ayahuasca ceremonials were requested to volunteer for binocular rivalry tests (DSA=0, 3.75, 7.5, 15 and 30 Hz) without and after drinking the brew. Ingestion of ayahuasca increased mean dominance periods both in standard binocular rivalry conditions (no DSA) and tests with DSA. At higher DSA rates (15 and 30 Hz) the total length of dominance periods was longer on the brew. It is discussed that ayahuasca-induced survival of binocular rivalry at high DSA rates may be related to slow visual processing and increased mean dominance periods may result from hallucinogen-induced alteration of gamma oscillations in the visual pathways.

  16. Flavor Identification and Intensity: Effects of Stimulus Context.

    Science.gov (United States)

    Hallowell, Emily S; Parikh, Roshan; Veldhuizen, Maria G; Marks, Lawrence E

    2016-03-01

    Two experiments presented oral mixtures containing different proportions of the gustatory flavorant sucrose and an olfactory flavorant, either citral (Experiment 1) or lemon (Experiment 2). In 4 different sessions of each experiment, subjects identified each mixture as "mostly sugar" or "mostly citrus/lemon" or rated the perceived intensities of the sweet and citrus components. Different sessions also presented the mixtures in different contexts, with mixtures containing relatively high concentrations of sucrose or citral/lemon presented more often (skew sucrose or skew citral/lemon). As expected, in both experiments, varying stimulus context affected both identification and perceived intensity: Skewing to sucrose versus citral/lemon decreased the probability of identifying the stimuli as "mostly sugar" and reduced the ratings of sweet intensity relative to citrus intensity. Across both contextual conditions of both experiments, flavor identification associated closely with the ratio of the perceived sweet and citrus intensities. The results accord with a model, extrapolated from signal-detection theory, in which sensory events are represented as multisensory-multidimensional distributions in perceptual space. Changing stimulus context can shift the locations of the distributions relative to response criteria, Decision rules guide judgments based on both sensory events and criteria, these rules not necessarily being identical in tasks of identification and intensity rating. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Parietal cortex mediates perceptual Gestalt grouping independent of stimulus size.

    Science.gov (United States)

    Grassi, Pablo R; Zaretskaya, Natalia; Bartels, Andreas

    2016-06-01

    The integration of local moving elements into a unified gestalt percept has previously been linked to the posterior parietal cortex. There are two possible interpretations for the lack of involvement of other occipital regions. The first is that parietal cortex is indeed uniquely functionally specialized to perform grouping. Another possibility is that other visual regions can perform grouping as well, but that the large spatial separation of the local elements used previously exceeded their neurons' receptive field (RF) sizes, preventing their involvement. In this study we distinguished between these two alternatives. We measured whole-brain activity using fMRI in response to a bistable motion illusion that induced mutually exclusive percepts of either an illusory global Gestalt or of local elements. The stimulus was presented in two sizes, a large version known to activate IPS only, and a version sufficiently small to fit into the RFs of mid-level dorsal regions such as V5/MT. We found that none of the separately localized motion regions apart from parietal cortex showed a preference for global Gestalt perception, even for the smaller version of the stimulus. This outcome suggests that grouping-by-motion is mediated by a specialized size-invariant mechanism with parietal cortex as its anatomical substrate. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Discriminative stimulus properties of lysergic acid diethylamide in the monkey.

    Science.gov (United States)

    Nielsen, E B

    1985-07-01

    Four monkeys (Cercopithecus aethiops) were trained to discriminate 0.06 mg/kg of lysergic acid diethylamide (LSD) from saline in a two-key task in which correct responding was reinforced with food under a fixed ratio 32 schedule. The ED50 of LSD was 0.011 mg/kg. The nonhallucinogenic ergot, lisuride, and the hallucinogen, 5-methoxy-N,N-dimethyltryptamine, substituted completely for LSD (ED50 values were 0.0098 and 0.45 mg/kg, respectively). Mescaline (1-40 mg/kg), d-amphetamine (0.1-0.625 mg/kg) and apomorphine (0.1-0.5 mg/kg) did not substitute for LSD. In antagonism testing with ketanserin (1-10 mg/kg) or pirenperone (0.025 and 0.05 mg/kg), only the highest dose of pirenperone attenuated the LSD stimulus effect (to 55%). A 0.1-mg/kg dose of pirenperone produced nonresponding in three of four animals. The LSD cue was unaffected by clozapine (1 and 2 mg/kg), haloperidol (0.1 mg/kg) and pizotifen (0.6-1.8 mg/kg). The fact that lisuride does not readily cause hallucinations in humans, but yet substituted for LSD in primates, indicates that the LSD cue may not reflect the hallucinogenic properties of LSD. It is suggested that the LSD stimulus effect may depend on receptors (e.g., serotonergic) that, at the moment, are only poorly characterized.

  19. Toward Biofunctional Microneedles for Stimulus Responsive Drug Delivery.

    Science.gov (United States)

    Cahill, Ellen M; O'Cearbhaill, Eoin D

    2015-07-15

    Microneedles have recently been adopted for use as a painless and safe method of transdermal therapeutic delivery through physically permeating the stratum corneum. While microneedles create pathways to introduce drugs, they can also act as conduits for biosignal sensing. Here, we explore the development of microneedles as both biosensing and drug delivery platforms. Microneedle sensors are being developed for continuous monitoring of biopotentials and bioanalytes through the use of conductive and electrochemically reactive biomaterials. The range of therapeutics being delivered through microneedle devices has diversified, while novel bioabsorbable microneedles are undergoing first-in-human clinical studies. We foresee that future microneedle platform development will focus on the incorporation of biofunctional materials, designed to deliver therapeutics in a stimulus responsive fashion. Biofunctional microneedle patches will require improved methods of attaching to and conforming to epithelial tissues in dynamic environments for longer periods of time and thus present an assortment of new design challenges. Through the evolution of biomaterial development and microneedle design, biofunctional microneedles are proposed as a next generation of stimulus responsive drug delivery systems.

  20. Visual stimulus presentation using fiber optics in the MRI scanner.

    Science.gov (United States)

    Huang, Ruey-Song; Sereno, Martin I

    2008-03-30

    Imaging the neural basis of visuomotor actions using fMRI is a topic of increasing interest in the field of cognitive neuroscience. One challenge is to present realistic three-dimensional (3-D) stimuli in the subject's peripersonal space inside the MRI scanner. The stimulus generating apparatus must be compatible with strong magnetic fields and must not interfere with image acquisition. Virtual 3-D stimuli can be generated with a stereo image pair projected onto screens or via binocular goggles. Here, we describe designs and implementations for automatically presenting physical 3-D stimuli (point-light targets) in peripersonal and near-face space using fiber optics in the MRI scanner. The feasibility of fiber-optic based displays was demonstrated in two experiments. The first presented a point-light array along a slanted surface near the body, and the second presented multiple point-light targets around the face. Stimuli were presented using phase-encoded paradigms in both experiments. The results suggest that fiber-optic based displays can be a complementary approach for visual stimulus presentation in the MRI scanner.

  1. Does bimodal stimulus presentation increase ERP components usable in BCIs?

    Science.gov (United States)

    Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Blankertz, Benjamin; Werkhoven, Peter J.

    2012-08-01

    Event-related potential (ERP)-based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. Typically, visual stimuli are used. Tactile stimuli have recently been suggested as a gaze-independent alternative. Bimodal stimuli could evoke additional brain activity due to multisensory integration which may be of use in BCIs. We investigated the effect of visual-tactile stimulus presentation on the chain of ERP components, BCI performance (classification accuracies and bitrates) and participants’ task performance (counting of targets). Ten participants were instructed to navigate a visual display by attending (spatially) to targets in sequences of either visual, tactile or visual-tactile stimuli. We observe that attending to visual-tactile (compared to either visual or tactile) stimuli results in an enhanced early ERP component (N1). This bimodal N1 may enhance BCI performance, as suggested by a nonsignificant positive trend in offline classification accuracies. A late ERP component (P300) is reduced when attending to visual-tactile compared to visual stimuli, which is consistent with the nonsignificant negative trend of participants’ task performance. We discuss these findings in the light of affected spatial attention at high-level compared to low-level stimulus processing. Furthermore, we evaluate bimodal BCIs from a practical perspective and for future applications.

  2. Managing Input during Assistive Technology Product Design

    Science.gov (United States)

    Choi, Young Mi

    2011-01-01

    Many different sources of input are available to assistive technology innovators during the course of designing products. However, there is little information on which ones may be most effective or how they may be efficiently utilized within the design process. The aim of this project was to compare how three types of input--from simulation tools,…

  3. 39 CFR 3020.92 - Public input.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Public input. 3020.92 Section 3020.92 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PRODUCT LISTS Requests Initiated by the Postal Service to Change the Mail Classification Schedule § 3020.92 Public input. The Commission shall publish Postal...

  4. Farmers\\' Perceived Agricultural Input Factors Influencing Adoption ...

    African Journals Online (AJOL)

    The study investigated agricultural input factors influencing adoption and production of food crops in Ondo State, Nigeria. Data from 120 randomly selected farmers were used for the study. Findings show that the major inputs used by the respondents are improved seeds (89.2%), fertilizer (66.7%) and agrochemicals ...

  5. Farmer and input marketer's involvement in researchextension ...

    African Journals Online (AJOL)

    This study determined the level of involvement of farmers and input marketers in the Research-Extension-Farmer-Input Linkage System (REFILS) continuum of activities in the Southeastern agro-ecological zone of Nigeria. Data were collected with the aid of structured questionnaire administered to 80 randomly selected ...

  6. EDP Applications to Musical Bibliography: Input Considerations

    Science.gov (United States)

    Robbins, Donald C.

    1972-01-01

    The application of Electronic Data Processing (EDP) has been a boon in the analysis and bibliographic control of music. However, an extra step of encoding must be undertaken for input of music. The best hope to facilitate musical input is the development of an Optical Character Recognition (OCR) music-reading machine. (29 references) (Author/NH)

  7. Income distributions in input-output models

    NARCIS (Netherlands)

    Steenge, Albert E.; Serrano, Monica

    2012-01-01

    The analysis of income distribution (ID) has traditionally been of prime importance for economists and policy-makers. However, the standard input-output (I-O) model is not particularly well equipped for studying current issues such as the consequences of decreasing access to primary inputs or the

  8. Bone Growth, Mechanical Stimulus and IGF-I

    National Research Council Canada - National Science Library

    Gilsanz, Vicente

    2005-01-01

    .... The aim of this project is to establish whether bone acquisition in teenagers who have sustained a fracture and have low bone mass can be enhanced by changing environmental factors, such as mechanical loading...

  9. Atmospheric Nitrogen input to the Kattegat

    DEFF Research Database (Denmark)

    Asman, W.A.H.; Hertel, O.; Berkowicz, R.

    1995-01-01

    An overview is given of the processes involved in the atmospheric deposition of nitrogen compounds. These processes are incorporated in an atmospheric transport model that is used to calculate the nitrogen input to the Kattegat, the sea area between Denmark and Sweden. The model results show...... that the total atmospheric nitrogen input to the Kattegat is approximately 960 kg N km(-2) yr(-1). The nitrogen input to the Kattegat is dominated by the wet depositions of NHx (42%) and NOy (30%). The contribution from the dry deposition of NHx is 17% and that of the dry deposition of NOy is 11......%. The contribution of the atmospheric input of nitrogen to the Kattegat is about 30% of the total input including the net transport from other sea areas, runoff etc....

  10. Statistical identification of effective input variables. [SCREEN

    Energy Technology Data Exchange (ETDEWEB)

    Vaurio, J.K.

    1982-09-01

    A statistical sensitivity analysis procedure has been developed for ranking the input data of large computer codes in the order of sensitivity-importance. The method is economical for large codes with many input variables, since it uses a relatively small number of computer runs. No prior judgemental elimination of input variables is needed. The sceening method is based on stagewise correlation and extensive regression analysis of output values calculated with selected input value combinations. The regression process deals with multivariate nonlinear functions, and statistical tests are also available for identifying input variables that contribute to threshold effects, i.e., discontinuities in the output variables. A computer code SCREEN has been developed for implementing the screening techniques. The efficiency has been demonstrated by several examples and applied to a fast reactor safety analysis code (Venus-II). However, the methods and the coding are general and not limited to such applications.

  11. Sustainable agriculture: a challenge in Bangladesh

    Directory of Open Access Journals (Sweden)

    M.A.A. Faroque

    2011-12-01

    Full Text Available The sustainability of conventional agriculture in Bangladesh is under threat from the continuous degradation of land and water resources, and from declining yields due to indiscriminate use of agro-chemicals. Government is pursuing efforts to promote sustainable agriculture with emphasis on better use of on-farm resources and the reduction of external inputs. This paper presents four dimensions of agricultural sustainability as productivity, environmental stability, economical profitability, and social and economic equity. Six characters were selected to evaluate sustainability. Significant differences were found between the two systems (conventional and sustainable agriculture in crop diversification, soil fertility management, pests and diseases management, use of agro-chemicals and environmental issues. However, no significant variations were found in other indicators such as land-use pattern, crop yield and stability, risk and uncertainties, and food security. Although crop yield and financial return were found to be slightly higher in the conventional system, the economic return and value addition per unit of land did not show any difference. It can be suggested that sustainable agriculture has a tendency towards becoming environmental, economically and socially more sound than conventional agriculture, as it requires considerably less agro-chemicals, adds more organic matter to the soil, provides balanced food, and requires higher local inputs without markedly compromising output and financial benefits. Broad-policy measures, including the creation of mass awareness of adverse health effects of agrochemical-based products, are outlined for the promotion of sustainable agriculture.

  12. Participatory Research and Development for Sustainable Agriculture ...

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

    Research and development can no longer be the exclusive domain of scientists. To find sustainable solutions to development problems, a wider range of actors must be involved. It is crucial, for example, that local stakeholders provide input to the process. Participatory research and development (PR&D) offers such an ...

  13. Addressing sustainability in hotel management education: designing ...

    African Journals Online (AJOL)

    This paper reports on combining generic reference points that can be distilled from literature with the analysis of 18 face-to-face interviews with relevant stakeholders as input for designing a sustainability course within a (higher education) hotel management curriculum. The train of thought presented here shows that by ...

  14. Differential influence of sinusoidal and noisy inputs on synaptic connections in a network with STDP

    Science.gov (United States)

    Mayer, J.; Schuster, H. G.; Ngo, H.-V. V.; Mölle, M.; Born, J.

    2012-05-01

    We hypothesize that the type of cortical network activation influences synaptic connectivity in the network, eventually expressed in an altered responsiveness to external stimuli. Our predictions are based on a time discrete canonical model of spike-time-dependent plasticity. The results show that, at a given synaptic connection strength in the network, sinusoidal input to the network can decrease synaptic potentiation whereas uncorrelated noise increases synaptic potentiation, implying that these opposing effects manifest themselves in respective decreases and increases of the network response to an external stimulus. These predictions are in qualitative agreement with visually evoked responses obtained in humans after 9 hour periods of visual deprivation (used to increase sinusoidal EEG alpha-activity in cortical networks) or normal daytime vision (as an approximate of noise input).

  15. The eloquence of silent cortex: analysis of afferent input to deafferented cortex in arm amputees.

    Science.gov (United States)

    Mackert, Bruno-Marcel; Sappok, Tanja; Grüsser, Sabine; Flor, Herta; Curio, Gabriel

    2003-03-03

    Cortical reorganisation after limb amputation includes topographic displacements of body representation areas and changes of areal extent. Remarkably, truncated nerves, which had innervated amputated limb parts and remained in the residual limbs, can retain access to the deafferented somatosensory cortex. Using somatosensory evoked potentials (SEP) we characterized afferences from electrically stimulated truncated nerves to the brachial plexus and cortex in 12 arm amputees. While peripheral responses were highly variable, thalamocortical input to S-1, as reflected by the primary cortical SEP component, was present in 11 of 12 patients. Despite long-term deafferentation, macroscopic phenomena of inhibition/refractoriness, as assessed by stimulus rate variations, appeared to be changed only marginally. Thus, deafferented cortex remains responsive when given artificial phantom input and could provide a neuronal substrate for spontaneous phantom limb sensations, including phantom pain.

  16. Stimulus-specific adaptations in the gaze control system of the barn owl.

    Science.gov (United States)

    Reches, Amit; Gutfreund, Yoram

    2008-02-06

    Abrupt orientation to novel stimuli is a critical, memory-dependent task performed by the brain. In the present study, we examined two gaze control centers of the barn owl: the optic tectum (OT) and the arcopallium gaze fields (AGFs). Responses of neurons to long sequences of dichotic sound bursts comprised of two sounds differing in the probability of appearance were analyzed. We report that auditory neurons in the OT and in the AGFs tend to respond stronger to rarely presented sounds (novel sounds) than to the same sounds when presented frequently. This history-dependent phenomenon, known as stimulus-specific adaptation (SSA), was demonstrated for rare sound frequencies, binaural localization cues [interaural time difference (ITD) and level difference (ILD)] and sound amplitudes. The manifestation of SSA in such a variety of independent acoustic features, in the midbrain and in the forebrain, supports the notion that SSA is involved in sensory memory and novelty detection. To track the origin of SSA, we analyzed responses of neurons in the external nucleus of the inferior colliculus (ICX; the source of auditory input to the OT) to similar sequences of sound bursts. Neurons in the ICX responded stronger to rare sound frequencies, but did not respond differently to rare ITDs, ILDs, or sound amplitudes. We hypothesize that part of the SSA reported here is computed in high-level networks, giving rise to novelty signals that modulate tectal responses in a context-dependent manner.

  17. SK channel subtypes enable parallel optimized coding of behaviorally relevant stimulus attributes: A review.

    Science.gov (United States)

    Huang, Chengjie G; Chacron, Maurice J

    2017-07-04

    Ion channels play essential roles toward determining how neurons respond to sensory input to mediate perception and behavior. Small conductance calcium-activated potassium (SK) channels are found ubiquitously throughout the brain and have been extensively characterized both molecularly and physiologically in terms of structure and function. It is clear that SK channels are key determinants of neural excitability as they mediate important neuronal response properties such as spike frequency adaptation. However, the functional roles of the different known SK channel subtypes are not well understood. Here we review recent evidence from the electrosensory system of weakly electric fish suggesting that the function of different SK channel subtypes is to optimize the processing of independent but behaviorally relevant stimulus attributes. Indeed, natural sensory stimuli frequently consist of a fast time-varying waveform (i.e., the carrier) whose amplitude (i.e., the envelope) varies slowly and independently. We first review evidence showing how somatic SK2 channels mediate tuning and responses to carrier waveforms. We then review evidence showing how dendritic SK1 channels instead determine tuning and optimize responses to envelope waveforms based on their statistics as found in the organism's natural environment in an independent fashion. The high degree of functional homology between SK channels in electric fish and their mammalian orthologs, as well as the many important parallels between the electrosensory system and the mammalian visual, auditory, and vestibular systems, suggest that these functional roles are conserved across systems and species.

  18. Dynamics of Presynaptic Diacylglycerol in a Sensory Neuron Encode Differences between Past and Current Stimulus Intensity

    Directory of Open Access Journals (Sweden)

    Hayao Ohno

    2017-09-01

    Full Text Available Memorizing the intensity of sensory stimuli enables animals to successfully deal with changing environmental conditions and contributes to cognitive functions such as auditory and visual working memory. However, how nervous systems process past and current stimulus intensity is largely unknown at the molecular level. Here, we employ in vivo diacylglycerol (DAG imaging in the ASER taste neuron of Caenorhabditis elegans and demonstrate that associative learning between ambient salt concentrations and food can be explained by changes in presynaptic DAG. The abundance of DAG is regulated in response to external salt concentration changes via sensory transduction in ASER and can encode differences between past and current salt concentrations. The DAG dynamics are modulated downstream of the synaptic insulin/phosphatidylinositol 3-kinase (PI3K/Akt pathway, which regulates the behavioral plasticity induced by starvation. These results provide insights into how a single neuron stores past input intensity and generates appropriate behavioral responses.

  19. Discriminative identification of transcriptional responses of promoters and enhancers after stimulus

    KAUST Repository

    Kleftogiannis, Dimitrios A.

    2016-10-17

    Promoters and enhancers regulate the initiation of gene expression and maintenance of expression levels in spatial and temporal manner. Recent findings stemming from the Cap Analysis of Gene Expression (CAGE) demonstrate that promoters and enhancers, based on their expression profiles after stimulus, belong to different transcription response subclasses. One of the most promising biological features that might explain the difference in transcriptional response between subclasses is the local chromatin environment. We introduce a novel computational framework, PEDAL, for distinguishing effectively transcriptional profiles of promoters and enhancers using solely histone modification marks, chromatin accessibility and binding sites of transcription factors and co-activators. A case study on data from MCF-7 cell-line reveals that PEDAL can identify successfully the transcription response subclasses of promoters and enhancers from two different stimulations. Moreover, we report subsets of input markers that discriminate with minimized classification error MCF-7 promoter and enhancer transcription response subclasses. Our work provides a general computational approach for identifying effectively cell-specific and stimulation-specific promoter and enhancer transcriptional profiles, and thus, contributes to improve our understanding of transcriptional activation in human.

  20. Virtual Sustainability

    Directory of Open Access Journals (Sweden)

    William Sims Bainbridge

    2010-09-01

    Full Text Available In four ways, massively multiplayer online role-playing games may serve as tools for advancing sustainability goals, and as laboratories for developing alternatives to current social arrangements that have implications for the natural environment. First, by moving conspicuous consumption and other usually costly status competitions into virtual environments, these virtual worlds might reduce the need for physical resources. Second, they provide training that could prepare individuals to be teleworkers, and develop or demonstrate methods for using information technology to replace much transportation technology, notably in commuting. Third, virtual worlds and online games build international cooperation, even blending national cultures, thereby inching us toward not only the world consciousness needed for international agreements about the environment, but also toward non-spatial government that cuts across archaic nationalisms. Finally, realizing the potential social benefits of this new technology may urge us to reconsider a number of traditional societal institutions.

  1. Sustainability; Sustentabilidade

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-10-15

    This chapter analyses the production chain of ethanol, considering the impacts on the quality of the air, water supplies, soil occupation and biodiversity, and the efforts for the soil preservation. It is pointed out the activities of the production cycle and use of bio ethanol due to great uncertainties as far the environmental impacts is concerning and that will deserve more attention in future evaluations. At same time, the chapter highlights another activities where the present acknowledge is sufficient to assure the control and/or prediction of consequences of the desired intervention on the environment media to accommodate the sugar and ethanol production expansion. The consideration is not conservative but to promote the sustainable development.

  2. Environmental enrichment causes a global potentiation of neuronal responses across stimulus complexity and lamina of sensory cortex

    Directory of Open Access Journals (Sweden)

    Dasuni Sathsara Alwis

    2013-08-01

    Full Text Available Enriched social and physical housing produces many molecular, anatomical, electrophysiological and behaviour benefits even in adult animals. Much less is known of its effects on cortical electrophysiology, especially in how sensory cortex encodes the altered environment, and extant studies have generally been restricted to neurons in input laminae in sensory cortex. To extend the understanding of how an enriched environment alters the way in which cortex views the world, we investigated enrichment-induced changes in neuronal encoding of sensory stimuli across all laminae of the rat barrel cortex receiving input from the face whisker tactile system. Animals were housed in Enriched (n=13 or Isolated housing (n=13 conditions for 8 weeks before extracellular recordings were obtained from barrel cortex in response to simple whisker deflections and whisker motions modelling movements seen in awake animals undertaking a variety of different tasks. Enrichment resulted in increases in neuronal responses to all stimuli, ranging from those modelling exploratory behaviour through to discrimination behaviours. These increases were seen throughout the cortex from supragranular layers through to input Layer 4 and for some stimuli, in infragranular Layer 5. The observed enrichment-induced effect is consistent with the postulate that enrichment causes shift in cortical excitatory/inhibitory balance, and we demonstrate this is greatest in supragranular layers. However we also report that the effects are non-selective for stimulus parameters across a range of stimuli except for one modelling the likely use of whiskers by the rats in the enriched housing.

  3. Measuring Input Thresholds on an Existing Board

    Science.gov (United States)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and

  4. Sustainability Science Needs Sustainable Data!

    Science.gov (United States)

    Downs, R. R.; Chen, R. S.

    2013-12-01

    Sustainability science (SS) is an 'emerging field of research dealing with the interactions between natural and social systems, and with how those interactions affect the challenge of sustainability: meeting the needs of present and future generations while substantially reducing poverty and conserving the planet's life support systems' (Kates, 2011; Clark, 2007). Bettencourt & Kaur (2011) identified more than 20,000 scientific papers published on SS topics since the 1980s with more than 35,000 distinct authors. They estimated that the field is currently growing exponentially, with the number of authors doubling approximately every 8 years. These scholars are undoubtedly using and generating a vast quantity and variety of data and information for both SS research and applications. Unfortunately we know little about what data the SS community is actually using, and whether or not the data that SS scholars generate are being preserved for future use. Moreover, since much SS research is conducted by cross-disciplinary, multi-institutional teams, often scattered around the world, there could well be increased risks of data loss, reduced data quality, inadequate documentation, and poor long-term access and usability. Capabilities and processes therefore need to be established today to support continual, reliable, and efficient preservation of and access to SS data in the future, especially so that they can be reused in conjunction with future data and for new studies not conceived in the original data collection activities. Today's long-term data stewardship challenges include establishing sustainable data governance to facilitate continuing management, selecting data to ensure that limited resources are focused on high priority SS data holdings, securing sufficient rights to allow unforeseen uses, and preparing data to enable use by future communities whose specific research and information needs are not yet known. Adopting sustainable models for archival

  5. Grazing animal husbandry based on sustainable nutrient management

    NARCIS (Netherlands)

    Hermans, C.; Vereijken, P.H.

    1995-01-01

    Sustainable husbandry systems for grazing animals (cattle and sheep) can be achieved by sustainable nutrient management (SNM). This implies the tuning of inputs to outputs of nutrients, to achieve and maintain optimum ranges of agronomically wanted and ecologically acceptable reserves of single

  6. Soil Degradation, Policy Intervention and Sustainable Agricultural Growth

    NARCIS (Netherlands)

    Sasmal, J.; Weikard, H.P.

    2013-01-01

    Sustainable agricultural growth in developing countries is jeopardized by soil degradation consequent upon intensive cultivation and use of increasing doses of chemical inputs. To pave the way to sustainable agricultural growth we develop a model that incorporates organic fertilizer into the

  7. Relative contribution of expectancy and immediate arousal to the facilitatory effect of an auditory accessory stimulus

    Directory of Open Access Journals (Sweden)

    F. Del-Fava

    2004-08-01

    Full Text Available An auditory stimulus speeds up a digital response to a subsequent visual stimulus. This facilitatory effect has been related to the expectancy and the immediate arousal that would be caused by the accessory stimulus. The present study examined the relative contribution of these two influences. In a first and a third experiment a simple reaction time task was used. In a second and fourth experiment a go/no-go reaction time task was used. In each of these experiments, the accessory stimulus preceded the target stimulus by 200 ms for one group of male and female volunteers (G Fix. For another group of similar volunteers (G Var the accessory stimulus preceded the target stimulus by 200 ms in 25% of the trials, by 1000 ms in 25% of the trials and was not followed by the target stimulus in 50% of the trials (Experiments 1a and 1b or preceded the target stimulus by 200 ms in 6% of the trials and by 1000 ms in 94% of the trials (Experiments 2a and 2b. There was a facilitatory effect of the accessory stimulus for G Fix in the four experiments. There was also a facilitatory effect of the accessory stimulus at the 200-ms stimulus onset asynchrony for G Var in Experiments 1a and 1b but not in Experiments 2a and 2b. The facilitatory effects observed were larger in the go/no-go task than in the simple task. Taken together, these results suggest that expectancy is much more important than immediate arousal for the improvement of performance caused by an accessory stimulus.

  8. Decreased Hering-Breuer input-output entrainment in a mouse model of Rett syndrome.

    Science.gov (United States)

    Dhingra, Rishi R; Zhu, Yenan; Jacono, Frank J; Katz, David M; Galán, Roberto F; Dick, Thomas E

    2013-01-01

    Rett syndrome, a severe X-linked neurodevelopmental disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (Mecp2), is associated with a highly irregular respiratory pattern including severe upper-airway dysfunction. Recent work suggests that hyperexcitability of the Hering-Breuer reflex (HBR) pathway contributes to respiratory dysrhythmia in Mecp2 mutant mice. To assess how enhanced HBR input impacts respiratory entrainment by sensory afferents in closed-loop in vivo-like conditions, we investigated the input (vagal stimulus trains) - output (phrenic bursting) entrainment via the HBR in wild-type and MeCP2-deficient mice. Using the in situ perfused brainstem preparation, which maintains an intact pontomedullary axis capable of generating an in vivo-like respiratory rhythm in the absence of the HBR, we mimicked the HBR feedback input by stimulating the vagus nerve (at threshold current, 0.5 ms pulse duration, 75 Hz pulse frequency, 100 ms train duration) at an inter-burst frequency matching that of the intrinsic oscillation of the inspiratory motor output of each preparation. Using this approach, we observed significant input-output entrainment in wild-type mice as measured by the maximum of the cross-correlation function, the peak of the instantaneous relative phase distribution, and the mutual information of the instantaneous phases. This entrainment was associated with a reduction in inspiratory duration during feedback stimulation. In contrast, the strength of input-output entrainment was significantly weaker in Mecp2 (-/+) mice. However, Mecp2 (-/+) mice also had a reduced inspiratory duration during stimulation, indicating that reflex behavior in the HBR pathway was intact. Together, these observations suggest that the respiratory network compensates for enhanced sensitivity of HBR inputs by reducing HBR input-output entrainment.

  9. Decreased Hering-Breuer input-output entrainment in a mouse model of Rett syndrome

    Directory of Open Access Journals (Sweden)

    Rishi R Dhingra

    2013-04-01

    Full Text Available Rett syndrome, a severe X-linked neurodevelopmental disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (Mecp2, is associated with a highly irregular respiratory pattern including severe upper-airway dysfunction. Recent work suggests that hyperexcitability of the Hering-Breuer reflex (HBR pathway contributes to respiratory dysrhythmia in Mecp2 mutant mice. To assess how enhanced HBR input impacts respiratory entrainment by sensory afferents in closed-loop in vivo-like conditions, we investigated the input (vagal stimulus trains – output (phrenic bursting entrainment via the HBR in wild-type and Mecp2-deficient mice. Using the in situ perfused brainstem preparation, which maintains an intact pontomedullary axis capable of generating an in vivo-like respiratory rhythm in the absence of the HBR, we mimicked the HBR feedback input by stimulating the vagus nerve (at threshold current, 0.5 ms pulse duration, 75 Hz pulse frequency, 100 ms train duration at an inter-burst frequency matching that of the intrinsic oscillation of the inspiratory motor output of each preparation. Using this approach, we observed significant input-output entrainment in wild-type mice as measured by the maximum of the cross-correlation function, the peak of the instantaneous relative phase distribution, and the mutual information of the instantaneous phases. This entrainment was associated with a reduction in inspiratory duration during feedback stimulation. In contrast, the strength of input-output entrainment was significantly weaker in Mecp2-/+ mice. However, Mecp2-/+ mice also had a reduced inspiratory duration during stimulation, indicating that reflex behavior in the HBR pathway was intact. Together, these observations suggest that the respiratory network compensates for enhanced sensitivity of HBR inputs by reducing HBR input-output entrainment.

  10. Learning Structure of Sensory Inputs with Synaptic Plasticity Leads to Interference

    Directory of Open Access Journals (Sweden)

    Joseph eChrol-Cannon

    2015-08-01

    Full Text Available Synaptic plasticity is often explored as a form of unsupervised adaptationin cortical microcircuits to learn the structure of complex sensoryinputs and thereby improve performance of classification and prediction. The question of whether the specific structure of the input patterns is encoded in the structure of neural networks has been largely neglected. Existing studies that have analyzed input-specific structural adaptation have used simplified, synthetic inputs in contrast to complex and noisy patterns found in real-world sensory data.In this work, input-specific structural changes are analyzed forthree empirically derived models of plasticity applied to three temporal sensory classification tasks that include complex, real-world visual and auditory data. Two forms of spike-timing dependent plasticity (STDP and the Bienenstock-Cooper-Munro (BCM plasticity rule are used to adapt the recurrent network structure during the training process before performance is tested on the pattern recognition tasks.It is shown that synaptic adaptation is highly sensitive to specific classes of input pattern. However, plasticity does not improve the performance on sensory pattern recognition tasks, partly due to synaptic interference between consecutively presented input samples. The changes in synaptic strength produced by one stimulus are reversed by thepresentation of another, thus largely preventing input-specific synaptic changes from being retained in the structure of the network.To solve the problem of interference, we suggest that models of plasticitybe extended to restrict neural activity and synaptic modification to a subset of the neural circuit, which is increasingly found to be the casein experimental neuroscience.

  11. Integrating agronomic principles into production function estimation: A dichotomy of growth inputs and facilitating inputs

    NARCIS (Netherlands)

    Zhengfei, G.; Oude Lansink, A.G.J.M.; Ittersum, van M.K.; Wossink, G.A.A.

    2006-01-01

    This article presents a general conceptual framework for integrating agronomic principles into economic production analysis. We categorize inputs in crop production into growth inputs and facilitating inputs. Based on this dichotomy we specify an asymmetric production function. The robustness of the

  12. Stimulus encoding within the barn owl optic tectum using gamma oscillations vs. spike rate: a modeling approach.

    Science.gov (United States)

    Patel, Mainak; Reed, Mike

    2013-01-01

    The optic tectum of the barn owl is a multimodal structure with multiple layers, with each layer topographically organized according to spatial receptive field. The response of a site to a stimulus can be measured as either spike rate or local field potential (LFP) gamma (25-90 Hz) power; within superficial layers, spike rate and gamma power spatial tuning curves are narrow and contrast-response functions rise slowly. Within deeper layers, however, spike rate tuning curves broaden and gamma power contrast-response functions sharpen. In this work, we employ a computational model to describe the inputs required to generate these transformations from superficial to deep layers and show that gamma power and spike rate can act as parallel information processing streams.

  13. Energy Security, Innovation & Sustainability Initiative

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-04-30

    's National Laboratories, that can provide real-world improvements in both the short- and long-term. Indeed, the roles of government and the private sector in energy sustainability were brought into sharper focus by the pending American Recovery and Reinvestment Act of 2009, also known as the economic stimulus bill. There was cautious optimism that the bill was moving the nation in the right direction by way of focusing on greater energy efficiency, alternative forms of energy and improved infrastructure. Nevertheless, there was concern over Congress picking energy winners and losers. Instead, Congress should challenge industry to produce solutions that will create a clear path forward to energy sustainability that the American people can support.

  14. Recognition memory for pictorial stimuli: biasing effects of stimulus emotionality.

    Science.gov (United States)

    Fernández-Rey, José; Redondo, Jaime

    2007-08-01

    The possibility that stimulus emotionality might influence recognition bias in a long-term memory task was studied with respect to both the valence and arousal dimensions of emotion. For this purpose, we used 108 International Affective Picture System pictures that were representative of all regions of this two-dimensional space. Signal detection theory analysis was applied using A'and B'' D as discrimination and bias measures, respectively. In general, the results showed that greater discrimination was accompanied by a response bias that was more conservative for pleasant and for unarousing pictures than for unpleasant and for arousing ones. These results provide new evidence in connection with the emotion-induced recognition bias in long-term memory performance.

  15. The Effects of Audiovisual Inputs on Solving the Cocktail Party Problem in the Human Brain: An fMRI Study.

    Science.gov (United States)

    Li, Yuanqing; Wang, Fangyi; Chen, Yongbin; Cichocki, Andrzej; Sejnowski, Terrence

    2017-09-25

    At cocktail parties, our brains often simultaneously receive visual and auditory information. Although the cocktail party problem has been widely investigated under auditory-only settings, the effects of audiovisual inputs have not. This study explored the effects of audiovisual inputs in a simulated cocktail party. In our fMRI experiment, each congruent audiovisual stimulus was a synthesis of 2 facial movie clips, each of which could be classified into 1 of 2 emotion categories (crying and laughing). Visual-only (faces) and auditory-only stimuli (voices) were created by extracting the visual and auditory contents from the synthesized audiovisual stimuli. Subjects were instructed to selectively attend to 1 of the 2 objects contained in each stimulus and to judge its emotion category in the visual-only, auditory-only, and audiovisual conditions. The neural representations of the emotion features were assessed by calculating decoding accuracy and brain pattern-related reproducibility index based on the fMRI data. We compared the audiovisual condition with the visual-only and auditory-only conditions and found that audiovisual inputs enhanced the neural representations of emotion features of the attended objects instead of the unattended objects. This enhancement might partially explain the benefits of audiovisual inputs for the brain to solve the cocktail party problem. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. The perception of regularity in an isochronous stimulus in zebra finches (Taeniopygia guttata) and humans.

    Science.gov (United States)

    van der Aa, Jeroen; Honing, Henkjan; ten Cate, Carel

    2015-06-01

    Perceiving temporal regularity in an auditory stimulus is considered one of the basic features of musicality. Here we examine whether zebra finches can detect regularity in an isochronous stimulus. Using a go/no go paradigm we show that zebra finches are able to distinguish between an isochronous and an irregular stimulus. However, when the tempo of the isochronous stimulus is changed, it is no longer treated as similar to the training stimulus. Training with three isochronous and three irregular stimuli did not result in improvement of the generalization. In contrast, humans, exposed to the same stimuli, readily generalized across tempo changes. Our results suggest that zebra finches distinguish the different stimuli by learning specific local temporal features of each individual stimulus rather than attending to the global structure of the stimuli, i.e., to the temporal regularity. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Sustainable Scientists

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Evan

    2008-12-31

    Scientists are front and center in quantifying and solving environmental problems. Yet, as a spate of recent news articles in scientific journals point out, much can be done to enhance sustainability within the scientific enterprise itself, particularly by trimming the energy use associated with research facilities and the equipment therein (i,ii,iii, iv). Sponsors of research unwittingly spend on the order of $10 billion each year on energy in the U.S. alone, and the underlying inefficiencies drain funds from the research enterprise while causing 80 MT CO2-equivalent greenhouse-gas emissions (see Box). These are significant sums considering the opportunity costs in terms of the amount of additional research that could be funded and emissions that could be reduced if the underlying energy was used more efficiently. By following commercially proven best practices in facility design and operation, scientists--and the sponsors of science--can cost-effectively halve these costs, while doing their part to put society on alow-carbon diet.

  18. Input data to run Landis-II

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The data are input data files to run the forest simulation model Landis-II for Isle Royale National Park. Files include: a) Initial_Comm, which includes the location...

  19. Input-output rearrangement of isolated converters

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Kovacevic, Milovan; Mønster, Jakob Døllner

    2015-01-01

    This paper presents a new way of rearranging the input and output of isolated converters. The new arrangement posses several advantages, as increased voltage range, higher power handling capabilities, reduced voltage stress and improved efficiency, for applications where galvanic isolation...

  20. Neural correlates of the formation and retention of cocaine-induced stimulus-reward associations

    OpenAIRE

    Nelissen, Koen; Jarraya, Bechir; Arsenault, John; Rosen, Bruce; Wald, Lawrence,; Mandeville, Joseph; Marota, John; Vanduffel, Wim

    2012-01-01

    Background: Cocaine can elicit drug-seeking behavior for drug-predicting stimuli, even after a single stimulus-cocaine pairing. While orbitofrontal cortex is thought to be important during encoding and maintenance of stimulus-reward value, we still lack a comprehensive model of the neural circuitry underlying this cognitive process. Methods: We studied the conditioned effects of cocaine using monkey fMRI and classical conditioning by pairing a visual shape (conditioning stimulus, CS+) wit...

  1. Lifespan development of stimulus-response conflict cost: similarities and differences between maturation and senescence

    OpenAIRE

    Li, S.; Hämmerer, D.; Müller, V.; Hommel, B.; Lindenberger, U.

    2008-01-01

    Age gradient of the mechanism of stimulus-response conflict cost was investigated in a population-based representative sample of 291 individuals, covering the age range from 6 to 89 years. Stimulus-response conflict cost, indicated by the amount of additional processing time required when there is a conflict between stimulus and response options, follows a U-shaped function across the lifespan. Lifespan age gradient of conflict cost parallels closely those of processing fluctuation and fluid ...

  2. THE KNOWLEDGE OF ROMANIAN AGRICULTURE IN TERMS OF SUSTAINABILITY

    Directory of Open Access Journals (Sweden)

    Iuliana DOBRE

    2013-01-01

    Full Text Available Agriculture, a key component of the structure of economic branches, should be addressed directly related to the maintenance of natural resources and their exploitation in a controlled way or the enhancement of their own, without resorting to inconsistent stimulus elements that can in time generate dysfunctions in products and the environment. Looking at things from this perspective, there is a need for a sustainable agriculture approach, given its social, ecological and economic representativeness, with active and continuous character.

  3. Sustainable agriculture - selected papers

    OpenAIRE

    Krasowicz, Stanisław; Wrzaszcz, Wioletta; Zegar, Jozef St.

    2007-01-01

    The concept of research on socially sustainable agriculture. Features of sustainable agriculture. Sustainability of private farms in the light of selected criteria. Subsistence agricultural holdings and the sustainable development of agriculture. Sustainable farms in the light of the FADN data. Description of organic holdings in Poland.

  4. Significance of Input Correlations in Striatal Function

    Science.gov (United States)

    Yim, Man Yi; Aertsen, Ad; Kumar, Arvind

    2011-01-01

    The striatum is the main input station of the basal ganglia and is strongly associated with motor and cognitive functions. Anatomical evidence suggests that individual striatal neurons are unlikely to share their inputs from the cortex. Using a biologically realistic large-scale network model of striatum and cortico-striatal projections, we provide a functional interpretation of the special anatomical structure of these projections. Specifically, we show that weak pairwise correlation within the pool of inputs to individual striatal neurons enhances the saliency of signal representation in the striatum. By contrast, correlations among the input pools of different striatal neurons render the signal representation less distinct from background activity. We suggest that for the network architecture of the striatum, there is a preferred cortico-striatal input configuration for optimal signal representation. It is further enhanced by the low-rate asynchronous background activity in striatum, supported by the balance between feedforward and feedback inhibitions in the striatal network. Thus, an appropriate combination of rates and correlations in the striatal input sets the stage for action selection presumably implemented in the basal ganglia. PMID:22125480

  5. The effect of different stimulus attributes on the attentional performance of children with attention deficit/hyperactivity disorder and dyslexia.

    Science.gov (United States)

    Wang, Li-Chih; Tsai, Huang-Ju; Yang, Hsien-Ming

    2013-11-01

    While teachers have traditionally used the interesting objects to increase student attention in the classroom, evidence supporting the effectiveness of this method is lacking. The present study investigated the influence of different stimulus attributes for typical developing students and for students with attention deficit/hyperactivity disorder (ADHD) and dyslexia. Thirty children with ADHD, 30 children with dyslexia, and 30 typical developing students were tested using a measuring tool that was constructed by the authors to assess their sustained attention and selective attention on the geometric-figure assessment and the interesting-figure assessment. The geometric-figure assessment included a square, circle, trapezium, and triangle; and the interesting-figure assessment included a house, cat, hand, and tree. While the typical developing group showed better selective attention on the geometric-figure assessment, there was no difference between the dyslexic group and the ADHD group with respect to selective attention. Furthermore, the typical developing and dyslexic groups did not differ in the geometric-figure assessment in sustained attention and were both better in this area than the ADHD group. In the interesting-figure assessment, the typical developing and dyslexic groups performed similarly in sustained attention, but selective attention of the dyslexic group improved more than the ADHD group, similar to the typical developing group. Both selective attention of the dyslexic group and sustained attention of the ADHD group showed positive significant differences in the interesting-figure assessment, but sustained attention of the dyslexic group and selective attention of the ADHD group showed little difference in the interesting-figure assessment. Surprisingly, the typical developing group did not show any significant difference in the interesting-figure assessment, possibly because they had previously demonstrated a ceiling effect in the geometric

  6. Order of stimulus presentation modulates interference in Stroop matching tasks: a reaction time study

    OpenAIRE

    Caldas, Ariane Leão; David, Isabel de Paula Antunes; Portes, Paula Martins; Portugal, Anna Carolina de Almeida; Machado-Pinheiro, Walter

    2015-01-01

    In the classic Stroop effect, the time spent to name the color of an incongruent stimulus (GREEN in blue) is longer than the time necessary to name the color of a congruent stimulus (BLUE in blue). In the “Stroop matching task”, volunteers are instructed to compare attributes of two stimuli, in which one of them is necessarily a Stroop stimulus. Our aim was to investigate whether the order of stimulus presentation can explain some contradictory results and reveal the imposition of high-order ...

  7. The Impacts of Facial Tones and Stimulus Durations on Perceived Oldness and Attractiveness

    Directory of Open Access Journals (Sweden)

    Ji Yeon Lee

    2011-05-01

    Full Text Available Two experiments were conducted to investigate the impacts of facial tone and stimulus duration on perceived oldness and judgement of attraction. The stimulus were facial images of Asians. Facial tone (bright, middle, dark and stimulus duration (50ms, 200ms, 800ms were manipulated. In Experiment 1 perceived oldness was measured, and in Experiment 2 attractiveness was evaluated. The results showed that face was perceived older and less attractive with increase facial tone facial regardless of stimulus duration. This suggest that perceived oldness and judgement of attraction are closely related and affected primarily by facial tone.

  8. Sustainable NREL - Site Sustainability Plan FY 2015

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-01-01

    NREL's Site Sustainability Plan FY 2015 reports on sustainability plans for the lab for the year 2015 based on Executive Order Goals and provides the status on planned actions cited in the FY 2014 report.

  9. Measuring input synchrony in the Ornstein-Uhlenbeck neuronal model through input parameter estimation.

    Science.gov (United States)

    Koutsou, Achilleas; Kanev, Jacob; Christodoulou, Chris

    2013-11-06

    We present a method of estimating the input parameters and through them, the input synchrony, of a stochastic leaky integrate-and-fire neuronal model based on the Ornstein-Uhlenbeck process when it is driven by time-dependent sinusoidal input signal and noise. By driving the neuron using sinusoidal inputs, we simulate the effects of periodic synchrony on the membrane voltage and the firing of the neuron, where the peaks of the sine wave represent volleys of synchronised input spikes. Our estimation methods allow us to measure the degree of synchrony driving the neuron in terms of the input sine wave parameters, using the output spikes of the model and the membrane potential. In particular, by estimating the frequency of the synchronous input volleys and averaging the estimates of the level of input activity at corresponding intervals of the input signal, we obtain fairly accurate estimates of the baseline and peak activity of the input, which in turn define the degrees of synchrony. The same procedure is also successfully applied in estimating the baseline and peak activity of the noise. This article is part of a Special Issue entitled Neural Coding 2012. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Sustainability in Transport Planning

    DEFF Research Database (Denmark)

    Gudmundsson, Henrik; Greve, Carsten

    Contribution to session J: Joint University Sustainability Initiatives. This session will provide an inspiring overview of interdisciplinary research and teaching activities on sustainability bridging DTU, KU, and CBS, and introduce the joint collaboration Copenhagen Sustainability Initiative (COSI...

  11. Sustainability : Politics and governance

    NARCIS (Netherlands)

    Heinrichs, Harald; Biermann, Frank

    2016-01-01

    he article gives an overview of global sustainability policy and politics. It is shown how international policy making on sustainable development has progressed from environmental policy toward recent approaches of Earth system governance. Key challenges of international sustainability politics are

  12. Textiles and clothing sustainability sustainable technologies

    CERN Document Server

    2017-01-01

    This is the first book to deal with the innovative technologies in the field of textiles and clothing sustainability. It details a number of sustainable and innovative technologies and highlights their implications in the clothing sector. There are currently various measures to achieve sustainability in the textiles and the clothing industry, including innovations in the manufacturing stage, which is the crux of this book.

  13. Assessment of Sustainability of Sports Events (Slovenia

    Directory of Open Access Journals (Sweden)

    Aleksandra Golob

    2015-04-01

    Full Text Available Events industry plays an important role in nowadays economy and can have a substantial impact for a successful business; in addition, sustainability-oriented tourism is becoming an important component of development and planning of a tourist destination. Thus, organizing sustainability-oriented events is crucial and should focus on the zero waste event management and consider as many elements of sustainable development as possible. The same stands for organizing sports events. The aim of this paper was to find out to which level the organizers of existing sports events in Slovenia are taking into account different domains of sustainable development. Answering to a common questionnaire the organizers gave us a feedback considering four main areas: environmental, social, cultural, and economic criteria. The plan was to determine the level of sustainability of three sports events and compare them to each other according to the outstanding areas as well as to draw the attention to the importance of organizing sustainability-oriented sports events and minimizing negative effects of those. Since the field of research is complex, dynamic, and has an interdisciplinary character the results were attained using the DEX software which supports a qualitative approach and allows the modelling of complex decision-making processes with a large number of parameters and alternatives. Such methodology enables the input of a preliminary set of sustainability criteria and can be used as a support when deciding on the evaluation of sustainability of events in general.

  14. Stimulus-dependent synchronization in delayed-coupled neuronal networks.

    Science.gov (United States)

    Esfahani, Zahra G; Gollo, Leonardo L; Valizadeh, Alireza

    2016-03-22

    Time delay is a general feature of all interactions. Although the effects of delayed interaction are often neglected when the intrinsic dynamics is much slower than the coupling delay, they can be crucial otherwise. We show that delayed coupled neuronal networks support transitions between synchronous and asynchronous states when the level of input to the network changes. The level of input determines the oscillation period of neurons and hence whether time-delayed connections are synchronizing or desynchronizing. We find that synchronizing connections lead to synchronous dynamics, whereas desynchronizing connections lead to out-of-phase oscillations in network motifs and to frustrated states with asynchronous dynamics in large networks. Since the impact of a neuronal network to downstream neurons increases when spikes are synchronous, networks with delayed connections can serve as gatekeeper layers mediating the firing transfer to other regions. This mechanism can regulate the opening and closing of communicating channels between cortical layers on demand.

  15. Pattern-information analysis: from stimulus decoding to computational-model testing.

    Science.gov (United States)

    Kriegeskorte, Nikolaus

    2011-05-15

    Pattern-information analysis has become an important new paradigm in functional imaging. Here I review and compare existing approaches with a focus on the question of what we can learn from them in terms of brain theory. The most popular and widespread method is stimulus decoding by response-pattern classification. This approach addresses the question whether activity patterns in a given region carry information about the stimulus category. Pattern classification uses generic models of the stimulus-response relationship that do not mimic brain information processing and treats the stimulus space as categorical-a simplification that is often helpful, but also limiting in terms of the questions that can be addressed. We can address the question whether representations are consistent across different stimulus sets or tasks by cross-decoding, where the classifier is trained with one set of stimuli (or task) and tested with another. Beyond pattern classification, a major new direction is the integration of computational models of brain information processing into pattern-information analysis. This approach enables us to address the question to what extent competing computational models are consistent with the stimulus representations in a brain region. Two methods that test computational models are voxel receptive-field modeling and representational similarity analysis. These methods sample the stimulus (or mental-state) space more richly, estimate a separate response pattern for each stimulus, and can generalize from the stimulus sample to a stimulus population. Computational models that mimic brain information processing predict responses from stimuli. The reverse transform can be modeled to reconstruct stimuli from responses. Stimulus reconstruction is a challenging feat of engineering, but the implications of the results for brain theory are not always clear. Exploratory pattern analyses complement the confirmatory approaches mentioned so far and can reveal strong

  16. Fractal gait patterns are retained after entrainment to a fractal stimulus.

    Directory of Open Access Journals (Sweden)

    Christopher K Rhea

    Full Text Available Previous work has shown that fractal patterns in gait can be altered by entraining to a fractal stimulus. However, little is understood about how long those patterns are retained or which factors may influence stronger entrainment or retention. In experiment one, participants walked on a treadmill for 45 continuous minutes, which was separated into three phases. The first 15 minutes (pre-synchronization phase consisted of walking without a fractal stimulus, the second 15 minutes consisted of walking while entraining to a fractal visual stimulus (synchronization phase, and the last 15 minutes (post-synchronization phase consisted of walking without the stimulus to determine if the patterns adopted from the stimulus were retained. Fractal gait patterns were strengthened during the synchronization phase and were retained in the post-synchronization phase. In experiment two, similar methods were used to compare a continuous fractal stimulus to a discrete fractal stimulus to determine which stimulus type led to more persistent fractal gait patterns in the synchronization and post-synchronization (i.e., retention phases. Both stimulus types led to equally persistent patterns in the synchronization phase, but only the discrete fractal stimulus led to retention of the patterns. The results add to the growing body of literature showing that fractal gait patterns can be manipulated in a predictable manner. Further, our results add to the literature by showing that the newly adopted gait patterns are retained for up to 15 minutes after entrainment and showed that a discrete visual stimulus is a better method to influence retention.

  17. The importance of mineralogical input into geometallurgy programs

    Science.gov (United States)

    Hoal, K. Olson; Woodhead, J.D.; Smith, Kathleen S.

    2013-01-01

    Mineralogy is the link between ore formation and ore extraction. It is the most fundamental component of geomet programs, and the most important aspect of a life-of-project approach to mineral resource projects. Understanding orebodies is achieved by understanding the mineralogy and texture of the materials, throughout the process, because minerals hold the information required to unlock the value they contain. Geomet mineralogy programs absolutely require the appropriate expertise and at least three steps of mineral characterisation prior to using semi-automated or other methods: field examination, thorough core logging, and optical microscopy. Economic geological inputs for orebody characterisation are necessary for orebody understanding, and are exemplified by current research in the Zambian Copperbelt, where revised sequence stratigraphy and understanding of alteration, metasomatism and metamorphism can be used to predict topical issues at mine sites. Environmental inputs for sustainability characterisation are demonstrated by recent work on tailings from the Leadville, Colorado, USA area, including linking mineralogy to water quality issues. Risk assessments need to take into account the technical uncertainties around geological variability and mineral extractability, and mineralogy is the only metric that can be used to make this risk contribution.

  18. Reading input flooding versus listening input flooding: Can they boost speaking skill?

    Directory of Open Access Journals (Sweden)

    Rashtchi Mojgan

    2017-01-01

    Full Text Available The present study compared the effects of reading input flooding and listening input flooding techniques on the accuracy and complexity of Iranian EFL learners’ speaking skill. Participants were 66 homogeneous intermediate EFL learners who were randomly divided into three groups of 22: Reading input flooding group, listening input flooding group, and control group. The reading flooded input group was exposed to the numerous examples of the target structures through reading. In the same phase, the listening group was given relatively the same task, through listening. The participants’ monologues in the posttest were separately recorded, and later transcribed and coded in terms of accuracy and complexity through Bygate’s (2001 standard coding system. The results of ANCOVA indicated the outperformance of reading input flooding group. The study also supported the trade-off effects (Skehan, 1998, 2009 between accuracy and complexity.

  19. Shaped input distributions for structural damage localization

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Bernal, Dionisio; Damkilde, Lars

    2017-01-01

    localization method is cast, which operates on the premise of shaping inputs—whose spatial distribution is fixed—by use of a theoretical model such that these inputs, in one structural subdomain at the time, suppress certain steady-state vibration quantities (depending on the type of damage one seeks...... to interrogate for). Accordingly, damage is localized when the vibration signature induced by the shaped inputs in the damaged state corresponds to that in the reference state, hereby implying that the approach does not point directly to damage. Instead, it operates with interrogation based on postulated damage...... of two numerical examples, of which the first involves a chain-like system that is included to demonstrate some of the basic principles of the approach. The second example treats a truss structure model, which, besides the inputs to be shaped, is subjected to ambient excitation while the output...

  20. Stimulus-associated urinary urges in overactive bladder syndrome.

    Science.gov (United States)

    O'Connell, Kathleen A; Singer, Jonathan; Rajan, Sonali

    2017-05-02

    Although anecdotal reports of urinary urgency at one's front door are common in overactive bladder syndrome (OAB), little research has been done on how one's front door and other stimuli are related to urinary symptoms. We hypothesized that individuals with OAB would have higher scores on the Urinary Cues Questionnaire, developed for this study to assess stimulus-associated urinary urges, than those without OAB. Online surveys were administered to 328 women age 18-40 years recruited from a respondent panel maintained by CINT such that one-third of the sample reported a diagnosis of OAB. The survey assessed OAB symptoms and the frequency with which participants associated 42 stimuli with the urge to urinate. Psychometric analyses showed internal consistency estimates of the Urinary Cues Questionnaire of α = 0.97 and a test-retest correlation of 0.91. Women with OAB had significantly higher Urinary Cues Scores than those without OAB, with a t-test showing a large effect size of d = 1.49 (95%CI 1.24, 1.74), P research is needed on both treatment implications and on the trajectory of symptom development. © 2017 Wiley Periodicals, Inc.

  1. Flavor-Intensity Perception: Effects of Stimulus Context

    Science.gov (United States)

    Marks, Lawrence E.; Shepard, Timothy G.; Burger, Kelly; Chakwin, Emily M.

    2011-01-01

    Stimulus context affects judgments of intensity of both gustatory and olfactory flavors, and the contextual effects are modality-specific. Does context also exert separate effects on the gustatory and olfactory components of flavor mixtures? To answer this question, in each of 4 experiments, subjects rated the perceived intensity of 16 mixtures constructed by combining 4 concentrations of the gustatory flavorant sucrose with 4 concentrations of the retronasal olfactory flavorant citral. In 1 contextual condition of each experiment, concentrations of sucrose were relatively high and those of citral low; in the other condition, the relative concentrations of sucrose and citral reversed. There were 2 main results: First, consistent with earlier findings, in 5 of the 8 conditions, the ratings were consistent with linear addition of perceived sucrose and citral; departures from additivity appeared, however, in 3 conditions where the relative concentrations of citral were high. Second, changes in context produced contrast (adaptation-like changes) in perceived intensity: The contribution to perceived intensity of a given concentration of a flavorant was smaller when the contextual concentrations of that flavorant were high rather than low. A notable exception was the absence of contextual effects on the perceived intensity of near-threshold citral. These findings suggest that the contextual effects may arise separately in the gustatory and olfactory channels, prior to the integration of perceived flavor intensity. PMID:21930139

  2. Stimulus-responsive hydrogels: Theory, modern advances, and applications

    Science.gov (United States)

    Koetting, Michael C.; Peters, Jonathan T.; Steichen, Stephanie D.; Peppas, Nicholas A.

    2016-01-01

    Over the past century, hydrogels have emerged as effective materials for an immense variety of applications. The unique network structure of hydrogels enables very high levels of hydrophilicity and biocompatibility, while at the same time exhibiting the soft physical properties associated with living tissue, making them ideal biomaterials. Stimulus-responsive hydrogels have been especially impactful, allowing for unprecedented levels of control over material properties in response to external cues. This enhanced control has enabled groundbreaking advances in healthcare, allowing for more effective treatment of a vast array of diseases and improved approaches for tissue engineering and wound healing. In this extensive review, we identify and discuss the multitude of response modalities that have been developed, including temperature, pH, chemical, light, electro, and shear-sensitive hydrogels. We discuss the theoretical analysis of hydrogel properties and the mechanisms used to create these responses, highlighting both the pioneering and most recent work in all of these fields. Finally, we review the many current and proposed applications of these hydrogels in medicine and industry. PMID:27134415

  3. Create your own stimulus: Manipulating movements according to social categories.

    Science.gov (United States)

    Koppensteiner, Markus; Primes, Georg; Stephan, Pia

    2017-01-01

    People ascribe purposeful behaviour to the movements of artificial objects and social qualities to human body motion. We investigated how people associate simple motion cues with social categories. For a first rating-experiment we converted the body movements of speakers into stick-figure animations; for a second rating-experiment we used animations of one single dot. Rating-experiments were "reversed" because we asked participants to alter the movements (i.e., vertical amplitude, horizontal amplitude, and velocity) of the stimuli according to different instructions (e.g., create a stimulus of high dominance). Participants equipped stick figures and dot animations with expansive movements to represent high dominance. Expansive and fast movements (i.e., high velocity) were mainly associated with high aggressiveness. Fast movements were also associated with low friendliness, low trustworthiness, and low competence. Overall, patterns found for stick figure and dot animations were similar indicating that certain motion cues convey social information even when only a dot and no body form is visible. The "reverse approach" we propose here makes the impact of different components directly observable. The data generated by this method offers better insights into the interplay of these components and the ways in which they form meaningful patterns. The proposed method can be extended to other types of nonverbal cues and a variety of social categories.

  4. Create your own stimulus: Manipulating movements according to social categories.

    Directory of Open Access Journals (Sweden)

    Markus Koppensteiner

    Full Text Available People ascribe purposeful behaviour to the movements of artificial objects and social qualities to human body motion. We investigated how people associate simple motion cues with social categories. For a first rating-experiment we converted the body movements of speakers into stick-figure animations; for a second rating-experiment we used animations of one single dot. Rating-experiments were "reversed" because we asked participants to alter the movements (i.e., vertical amplitude, horizontal amplitude, and velocity of the stimuli according to different instructions (e.g., create a stimulus of high dominance. Participants equipped stick figures and dot animations with expansive movements to represent high dominance. Expansive and fast movements (i.e., high velocity were mainly associated with high aggressiveness. Fast movements were also associated with low friendliness, low trustworthiness, and low competence. Overall, patterns found for stick figure and dot animations were similar indicating that certain motion cues convey social information even when only a dot and no body form is visible. The "reverse approach" we propose here makes the impact of different components directly observable. The data generated by this method offers better insights into the interplay of these components and the ways in which they form meaningful patterns. The proposed method can be extended to other types of nonverbal cues and a variety of social categories.

  5. Validity of electrical stimulus magnitude matching in chronic pain.

    Science.gov (United States)

    Persson, Ann L; Westermark, Sofia; Merrick, Daniel; Sjölund, Bengt H

    2009-11-01

    To examine the validity of the PainMatcher in chronic pain. Comparison of parallel pain estimates from visual analogue scales with electrical stimulus magnitude matching. Thirty-one patients with chronic musculoskeletal pain. Twice a day ongoing pain was rated on a standard 100-mm visual analogue scale, and thereafter magnitude matching was performed using a PainMatcher. The sensory threshold to electrical stimulation was tested twice on separate occasions. In 438 observations visual analogue scale ranged from 3 to 95 (median 41) mm, and PainMatcher magnitudes from 2.67 to 27.67 (median 6.67; mean 7.78) steps. There was little correlation between visual analogue scale and magnitude data (r = 0.29; p visual analogue scale estimates covered the whole range of the instrument, the PainMatcher readings utilized only a small part of the instrument range and, importantly, had little or no relation to the visual analogue scale estimates. The validity of the PainMatcher procedure is doubtful.

  6. Smoking patterns and stimulus control in intermittent and daily smokers.

    Directory of Open Access Journals (Sweden)

    Saul Shiffman

    Full Text Available Intermittent smokers (ITS - who smoke less than daily - comprise an increasing proportion of adult smokers. Their smoking patterns challenge theoretical models of smoking motivation, which emphasize regular and frequent smoking to maintain nicotine levels and avoid withdrawal, but yet have gone largely unexamined. We characterized smoking patterns among 212 ITS (smoking 4-27 days per month compared to 194 daily smokers (DS; smoking 5-30 cigarettes daily who monitored situational antecedents of smoking using ecological momentary assessment. Subjects recorded each cigarette on an electronic diary, and situational variables were assessed in a random subset (n=21,539 smoking episodes; parallel assessments were obtained by beeping subjects at random when they were not smoking (n=26,930 non-smoking occasions. Compared to DS, ITS' smoking was more strongly associated with being away from home, being in a bar, drinking alcohol, socializing, being with friends and acquaintances, and when others were smoking. Mood had only modest effects in either group. DS' and ITS' smoking were substantially and equally suppressed by smoking restrictions, although ITS more often cited self-imposed restrictions. ITS' smoking was consistently more associated with environmental cues and contexts, especially those associated with positive or "indulgent" smoking situations. Stimulus control may be an important influence in maintaining smoking and making quitting difficult among ITS.

  7. Smoking Patterns and Stimulus Control in Intermittent and Daily Smokers

    Science.gov (United States)

    Shiffman, Saul; Dunbar, Michael S.; Li, Xiaoxue; Scholl, Sarah M.; Tindle, Hilary A.; Anderson, Stewart J.; Ferguson, Stuart G.

    2014-01-01

    Intermittent smokers (ITS) – who smoke less than daily – comprise an increasing proportion of adult smokers. Their smoking patterns challenge theoretical models of smoking motivation, which emphasize regular and frequent smoking to maintain nicotine levels and avoid withdrawal, but yet have gone largely unexamined. We characterized smoking patterns among 212 ITS (smoking 4–27 days per month) compared to 194 daily smokers (DS; smoking 5–30 cigarettes daily) who monitored situational antecedents of smoking using ecological momentary assessment. Subjects recorded each cigarette on an electronic diary, and situational variables were assessed in a random subset (n = 21,539 smoking episodes); parallel assessments were obtained by beeping subjects at random when they were not smoking (n = 26,930 non-smoking occasions). Compared to DS, ITS' smoking was more strongly associated with being away from home, being in a bar, drinking alcohol, socializing, being with friends and acquaintances, and when others were smoking. Mood had only modest effects in either group. DS' and ITS' smoking were substantially and equally suppressed by smoking restrictions, although ITS more often cited self-imposed restrictions. ITS' smoking was consistently more associated with environmental cues and contexts, especially those associated with positive or “indulgent” smoking situations. Stimulus control may be an important influence in maintaining smoking and making quitting difficult among ITS. PMID:24599056

  8. Stimulus-responsive hydrogels: Theory, modern advances, and applications.

    Science.gov (United States)

    Koetting, Michael C; Peters, Jonathan T; Steichen, Stephanie D; Peppas, Nicholas A

    2015-07-01

    Over the past century, hydrogels have emerged as effective materials for an immense variety of applications. The unique network structure of hydrogels enables very high levels of hydrophilicity and biocompatibility, while at the same time exhibiting the soft physical properties associated with living tissue, making them ideal biomaterials. Stimulus-responsive hydrogels have been especially impactful, allowing for unprecedented levels of control over material properties in response to external cues. This enhanced control has enabled groundbreaking advances in healthcare, allowing for more effective treatment of a vast array of diseases and improved approaches for tissue engineering and wound healing. In this extensive review, we identify and discuss the multitude of response modalities that have been developed, including temperature, pH, chemical, light, electro, and shear-sensitive hydrogels. We discuss the theoretical analysis of hydrogel properties and the mechanisms used to create these responses, highlighting both the pioneering and most recent work in all of these fields. Finally, we review the many current and proposed applications of these hydrogels in medicine and industry.

  9. Dynamic structure of joint-action stimulus-response activity.

    Directory of Open Access Journals (Sweden)

    MaryLauren Malone

    Full Text Available The mere presence of a co-actor can influence an individual's response behavior. For instance, a social Simon effect has been observed when two individuals perform a Go/No-Go response to one of two stimuli in the presence of each other, but not when they perform the same task alone. Such effects are argued to provide evidence that individuals co-represent the task goals and the to-be-performed actions of a co-actor. Motivated by the complex-systems approach, the present study was designed to investigate an alternative hypothesis--that such joint-action effects are due to a dynamical (time-evolving interpersonal coupling that operates to perturb the behavior of socially situated actors. To investigate this possibility, participants performed a standard Go/No-Go Simon task in joint and individual conditions. The dynamic structure of recorded reaction times was examined using fractal statistics and instantaneous cross-correlation. Consistent with our hypothesis that participants responding in a shared space would become behaviorally coupled, the analyses revealed that reaction times in the joint condition displayed decreased fractal structure (indicative of interpersonal perturbation processes modulating ongoing participant behavior compared to the individual condition, and were more correlated across a range of time-scales compared to the reaction times of pseudo-pair controls. Collectively, the findings imply that dynamic processes might underlie social stimulus-response compatibility effects and shape joint cognitive processes in general.

  10. ERP Indices of Stimulus Prediction in Letter Sequences

    Directory of Open Access Journals (Sweden)

    Edith Kaan

    2014-10-01

    Full Text Available Given the current focus on anticipation in perception, action and cognition, including language processing, there is a need for a method to tap into predictive processing in situations in which cue and feedback stimuli are not explicitly marked as such. To this aim, event related potentials (ERPs were obtained while participants viewed alphabetic letter sequences (“A”, “B”, “C”, “D”, “E”, …, in which the letters were highly predictable, and random sequences (“S”, “B”, “A”, “I”, “F”, “M”, …, without feedback. Occasionally, the presentation of a letter in a sequence was delayed by 300 ms. During this delay period, an increased negativity was observed for predictive versus random sequences. In addition, the early positivity following the delay was larger for predictive compared with random sequences. These results suggest that expectation-sensitive ERP modulations can be elicited in anticipation of stimuli that are not explicit targets, rewards, feedback or instructions, and that a delay can strengthen the prediction for a particular stimulus. Applications to language processing will be discussed.

  11. Estrogens mediate cardiac hypertrophy in a stimulus-dependent manner.

    Science.gov (United States)

    Haines, Christopher D; Harvey, Pamela A; Leinwand, Leslie A

    2012-09-01

    The incidence of cardiac hypertrophy, an established risk factor for heart failure, is generally lower in women compared with men, but this advantage is lost after menopause. Although it is widely believed that estrogens are cardioprotective, there are contradictory reports, including increased cardiac events in postmenopausal women receiving estrogens and enhanced cardiac protection from ischemic injury in female mice without estrogens. We exposed aromatase knockout (ArKO) mice, which produce no estrogens, to both pathologic and physiologic stimuli. This model allows an investigation into the effects of a complete, chronic lack of estrogens in male and female hearts. At baseline, female ArKO mice had normal-sized hearts but decreased cardiac function and paradoxically increased phosphorylation of many progrowth kinases. When challenged with the pathological stimulus, isoproterenol, ArKO females developed 2-fold more hypertrophy than wild-type females. In contrast, exercise-induced physiological hypertrophy was unaffected by the absence of estrogens in either sex, although running performance was blunted in ArKO females. Thus, loss of estrogen signaling in females, but not males, impairs cardiac function and sensitizes the heart to pathological insults through up-regulation of multiple hypertrophic pathways. These findings provide insight into the apparent loss of cardioprotection after menopause and suggest that caution is warranted in the long-term use of aromatase inhibitors in the setting of breast cancer prevention.

  12. Eyeblink conditioning with a noise burst as unconditioned stimulus.

    Science.gov (United States)

    Marcos Malmierca, José L; Marcos de Vega, Azahara

    2017-02-01

    The aim of this study was to determine if a white noise burst could be used as an effective unconditioned stimulus (US) to produce differential conditioning of eyeblink responses that were recorded as EMG activity of the orbicularis oculi. Two fear-relevant stimuli served as conditioned stimuli (CS). An angry woman’s face (CS+) was consistently followed by a white noise burst (US) with 100 dB intensity and 100 milliseconds in duration.  A fearful face of the same woman (CS-) was not followed by the US. CS duration was 500 milliseconds (ms) for 18 participants (long interval group), and 250 ms for 19 participants (short interval group). The US was presented in both groups immediately after terminating CS+. The results showed acquisition of differential conditioning in the long interval group, but not in the short interval group. These results suggest that a white noise burst as US could be used in one single experimental procedure which was capable of simultaneously producing conditioning in neural, autonomic and somatomotor response systems.

  13. Programmable Deployment of Tensegrity Structures by Stimulus-Responsive Polymers.

    Science.gov (United States)

    Liu, Ke; Wu, Jiangtao; Paulino, Glaucio H; Qi, H Jerry

    2017-06-14

    Tensegrity structures with detached struts are naturally suitable for deployable applications, both in terrestrial and outer-space structures, as well as morphing devices. Composed of discontinuous struts and continuous cables, such systems are only structurally stable when self-stress is induced; otherwise, they lose the original geometrical configuration (while keeping the topology) and thus can be tightly packed. We exploit this feature by using stimulus responsive polymers to introduce a paradigm for creating actively deployable 3D structures with complex shapes. The shape-change of 3D printed smart materials adds an active dimension to the configurational space of some structural components. Then we achieve dramatic global volume expansion by amplifying component-wise deformations to global configurational change via the inherent deployability of tensegrity. Through modular design, we can generate active tensegrities that are relatively stiff yet resilient with various complexities. Such unique properties enable structural systems that can achieve gigantic shape change, making them ideal as a platform for super light-weight structures, shape-changing soft robots, morphing antenna and RF devices, and biomedical devices.

  14. Harmonize input selection for sediment transport prediction

    Science.gov (United States)

    Afan, Haitham Abdulmohsin; Keshtegar, Behrooz; Mohtar, Wan Hanna Melini Wan; El-Shafie, Ahmed

    2017-09-01

    In this paper, three modeling approaches using a Neural Network (NN), Response Surface Method (RSM) and response surface method basis Global Harmony Search (GHS) are applied to predict the daily time series suspended sediment load. Generally, the input variables for forecasting the suspended sediment load are manually selected based on the maximum correlations of input variables in the modeling approaches based on NN and RSM. The RSM is improved to select the input variables by using the errors terms of training data based on the GHS, namely as response surface method and global harmony search (RSM-GHS) modeling method. The second-order polynomial function with cross terms is applied to calibrate the time series suspended sediment load with three, four and five input variables in the proposed RSM-GHS. The linear, square and cross corrections of twenty input variables of antecedent values of suspended sediment load and water discharge are investigated to achieve the best predictions of the RSM based on the GHS method. The performances of the NN, RSM and proposed RSM-GHS including both accuracy and simplicity are compared through several comparative predicted and error statistics. The results illustrated that the proposed RSM-GHS is as uncomplicated as the RSM but performed better, where fewer errors and better correlation was observed (R = 0.95, MAE = 18.09 (ton/day), RMSE = 25.16 (ton/day)) compared to the ANN (R = 0.91, MAE = 20.17 (ton/day), RMSE = 33.09 (ton/day)) and RSM (R = 0.91, MAE = 20.06 (ton/day), RMSE = 31.92 (ton/day)) for all types of input variables.

  15. The perception of regularity in an isochronous stimulus in zebra finches (Taeniopygia guttata) and humans

    NARCIS (Netherlands)

    van der Aa, J.; Honing, H.; ten Cate, C.

    2015-01-01

    Perceiving temporal regularity in an auditory stimulus is considered one of the basic features of musicality. Here we examine whether zebra finches can detect regularity in an isochronous stimulus. Using a go/no go paradigm we show that zebra finches are able to distinguish between an isochronous

  16. The Effects of Varying Latencies in the Stimulus-Response Paradigm of Speech Therapy.

    Science.gov (United States)

    Irwin, Ruth Beckey; And Others

    Effects of varying latencies upon articulatory productions in the stimulus-response paradigm were studied. Zero latency was compared to latency equal to stimuli and to latency with silent rehearsal of muscular movements. Thirty children with misarticulated /r/ from kindergarten, first, and second grades participated as subjects. Stimulus /ra/ was…

  17. With long intervals, inter-stimulus interval is the critical determinant of P300 amplitude

    NARCIS (Netherlands)

    Sambeth, A.; Maes, J.H.R.; Brankack, J.

    2004-01-01

    Previous research, using short inter-stimulus intervals (1-4 s), suggests that the P300 of the human event-related potential during oddball and single-stimulus tasks is mainly affected by target-to-target interval (TTI). The present study tested the validity of this claim at longer intervals in a

  18. Stimulus Competition in Pre/Post and Online Ratings in an Evaluative Learning Design

    Science.gov (United States)

    Purkis, Helena M.; Lipp, Ottmar V.

    2010-01-01

    Evaluative learning is said to differ from Pavlovian associative learning in that it reflects stimulus contiguity, not contingency. Thus, evaluative learning should not be subject to stimulus competition, a proposal tested in the current experiments. Participants were presented in elemental and compound training phases with pictures of shapes as…

  19. Anticipation increases tactile stimulus processing in the ipsilateral primary somatosensory cortex

    NARCIS (Netherlands)

    Ede, F.L. van; Lange, F.P. de; Maris, E.G.G.

    2014-01-01

    Stimulus anticipation improves perception. To account for this improvement, we investigated how stimulus processing is altered by anticipation. In contrast to a large body of previous work, we employed a demanding perceptual task and investigated sensory responses that occur beyond early evoked

  20. Unconditioned stimulus revaluation to promote conditioned fear extinction in the memory reconsolidation window.

    Directory of Open Access Journals (Sweden)

    Xiang-Xing Zeng

    Full Text Available The retrieval-extinction paradigm, which disrupts the reconsolidation of fear memories in humans, is a non-invasive technique that can be used to prevent the return of fear in humans. In the present study, unconditioned stimulus revaluation was applied in the retrieval-extinction paradigm to investigate its promotion of conditioned fear extinction in the memory reconsolidation window after participants acquired conditioned fear. This experiment comprised three stages (acquisition, unconditioned stimulus revaluation, retrieval-extinction and three methods for indexing fear (unconditioned stimulus expectancy, skin conductance response, conditioned stimulus pleasure rating. After the acquisition phase, we decreased the intensity of the unconditioned stimulus in one group (devaluation and maintained constant for the other group (control. The results indicated that both groups exhibited similar levels of unconditioned stimulus expectancy, but the devaluation group had significantly smaller skin conductance responses and exhibited a growth in conditioned stimulus + pleasure. Thus, our findings indicate unconditioned stimulus revaluation effectively promoted the extinction of conditioned fear within the memory reconsolidation window.

  1. Paradoxical intention vs stimulus control in the treatment of severe insomnia.

    Science.gov (United States)

    Ladouceur, R; Gros-Louis, Y

    1986-12-01

    This study compared the effectiveness of paradoxical intention, stimulus control, information and a control group on severe sleep onset insomnia. Results showed that paradoxical intention and stimulus control were equally effective but significantly better than the information and control groups. It is suggested that treatment be adapted for each individual according to data collected from the intensive behavioral analysis of each case.

  2. 75 FR 5041 - Extension of the Patent Application Backlog Reduction Stimulus Plan

    Science.gov (United States)

    2010-02-01

    ... Patent and Trademark Office Extension of the Patent Application Backlog Reduction Stimulus Plan AGENCY: United States Patent and Trademark Office, Commerce. ACTION: Notice. SUMMARY: The United States Patent... temporary basis (the Patent Application Backlog Reduction Stimulus Plan) under which a small entity...

  3. Positive and negative affect produce opposing task-irrelevant stimulus preexposure effects.

    Science.gov (United States)

    Lazar, Josef; Kaplan, Oren; Sternberg, Terri; Lubow, R E

    2012-06-01

    In three experiments, groups were exposed to either positive or negative affect video clips, after which they were presented with a series of task-irrelevant stimuli. In the subsequent test task, subjects were required to learn an association between the previously irrelevant stimulus and a consequence, and between a new stimulus and a consequence. Induced positive affect produced a latent inhibition effect (poorer evidence of learning with the previously irrelevant stimulus than with the novel stimulus). In opposition to this, induced negative affect resulted in better evidence of learning with a previously irrelevant stimulus than with a novel stimulus. In general, the opposing effects also were present in participants scoring high on self-report questionnaires of depression (Experiments 2 and 3). These unique findings were predicted and accounted for on the basis of two principles: (a) positive affect broadens the attentional field and negative affect contracts it; and (b) task-irrelevant stimuli are processed in two successive stages, the first encodes stimulus properties, and the second encodes stimulus relationships. The opposing influences of negative and positive mood on the processing of irrelevant stimuli have implications for the role of emotion in general theories of cognition, and possibly for resolving some of the inconsistent findings in research with schizophrenia patients.

  4. Effects of Stimulus Characteristics and Background Music on Foreign Language Vocabulary Learning and Forgetting

    Science.gov (United States)

    de Groot, Annette M. B.

    2006-01-01

    This study examined the effects of three stimulus variables and background music on paired-associate learning of foreign language (FL) vocabulary. The stimulus variables were the frequency and concreteness of the native language (L1) words and the (phonotactical) typicality of the FL words. Sixty-four L1-FL pairs were presented for learning six…

  5. Order of Stimulus Presentation Influences Children's Acquisition in Receptive Identification Tasks

    Science.gov (United States)

    Petursdottir, Anna Ingeborg; Aguilar, Gabriella

    2016-01-01

    Receptive identification is usually taught in matching-to-sample format, which entails the presentation of an auditory sample stimulus and several visual comparison stimuli in each trial. Conflicting recommendations exist regarding the order of stimulus presentation in matching-to-sample trials. The purpose of this study was to compare acquisition…

  6. An Examination of Stimulus Control in Fluency-Based Strategies: SAFMEDS and Generalization

    Science.gov (United States)

    Meindl, James N.; Ivy, Jonathan W.; Miller, Neal; Neef, Nancy A.; Williamson, Robert L.

    2013-01-01

    Fluency-based strategies such as Say All Fast a Minute Each Day Shuffled (SAFMEDS) effectively promote fluent responding (i.e., high rate and accuracy). It is possible, however, that the stimulus control developed through these activities inhibits stimulus generalization. We investigated this concern in a two-part study with college students.…

  7. A parallel input composite transimpedance amplifier

    Science.gov (United States)

    Kim, D. J.; Kim, C.

    2018-01-01

    A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

  8. Do efficiency scores depend on input mix?

    DEFF Research Database (Denmark)

    Asmild, Mette; Hougaard, Jens Leth; Kronborg, Dorte

    2013-01-01

    In this paper we examine the possibility of using the standard Kruskal-Wallis (KW) rank test in order to evaluate whether the distribution of efficiency scores resulting from Data Envelopment Analysis (DEA) is independent of the input (or output) mix of the observations. Since the DEA frontier...... is estimated, many standard assumptions for evaluating the KW test statistic are violated. Therefore, we propose to explore its statistical properties by the use of simulation studies. The simulations are performed conditional on the observed input mixes. The method, unlike existing approaches...

  9. Load Estimation from Natural input Modal Analysis

    DEFF Research Database (Denmark)

    Aenlle, Manuel López; Brincker, Rune; Canteli, Alfonso Fernández

    2005-01-01

    One application of Natural Input Modal Analysis consists in estimating the unknown load acting on structures such as wind loads, wave loads, traffic loads, etc. In this paper, a procedure to determine loading from a truncated modal model, as well as the results of an experimental testing programme...... estimation. In the experimental program a small structure subjected to vibration was used to estimate the loading from the measurements and the experimental modal space. The modal parameters were estimated by Natural Input Modal Analysis and the scaling factors of the mode shapes obtained by the mass change...

  10. Nuclear reaction inputs based on effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hilaire, S.; Peru, S.; Dubray, N.; Dupuis, M.; Bauge, E. [CEA, DAM, DIF, Arpajon (France); Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium)

    2016-11-15

    Extensive nuclear structure studies have been performed for decades using effective interactions as sole input. They have shown a remarkable ability to describe rather accurately many types of nuclear properties. In the early 2000 s, a major effort has been engaged to produce nuclear reaction input data out of the Gogny interaction, in order to challenge its quality also with respect to nuclear reaction observables. The status of this project, well advanced today thanks to the use of modern computers as well as modern nuclear reaction codes, is reviewed and future developments are discussed. (orig.)

  11. Comparison for younger and older adults: Stimulus temporal asynchrony modulates audiovisual integration.

    Science.gov (United States)

    Ren, Yanna; Ren, Yanling; Yang, Weiping; Tang, Xiaoyu; Wu, Fengxia; Wu, Qiong; Takahashi, Satoshi; Ejima, Yoshimichi; Wu, Jinglong

    2018-02-01

    Recent research has shown that the magnitudes of responses to multisensory information are highly dependent on the stimulus structure. The temporal proximity of multiple signal inputs is a critical determinant for cross-modal integration. Here, we investigated the influence that temporal asynchrony has on audiovisual integration in both younger and older adults using event-related potentials (ERP). Our results showed that in the simultaneous audiovisual condition, except for the earliest integration (80-110ms), which occurred in the occipital region for older adults was absent for younger adults, early integration was similar for the younger and older groups. Additionally, late integration was delayed in older adults (280-300ms) compared to younger adults (210-240ms). In audition‑leading vision conditions, the earliest integration (80-110ms) was absent in younger adults but did occur in older adults. Additionally, after increasing the temporal disparity from 50ms to 100ms, late integration was delayed in both younger (from 230 to 290ms to 280-300ms) and older (from 210 to 240ms to 280-300ms) adults. In the audition-lagging vision conditions, integration only occurred in the A100V condition for younger adults and in the A50V condition for older adults. The current results suggested that the audiovisual temporal integration pattern differed between the audition‑leading and audition-lagging vision conditions and further revealed the varying effect of temporal asynchrony on audiovisual integration in younger and older adults. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The speed of learning instructed stimulus-response association rules in human: experimental data and model.

    Science.gov (United States)

    Bugmann, Guido; Goslin, Jeremy; Duchamp-Viret, Patricia

    2013-11-06

    Humans can learn associations between visual stimuli and motor responses from just a single instruction. This is known to be a fast process, but how fast is it? To answer this question, we asked participants to learn a briefly presented (200ms) stimulus-response rule, which they then had to rapidly apply after a variable delay of between 50 and 1300ms. Participants showed a longer response time with increased variability for short delays. The error rate was low and did not vary with the delay, showing that participants were able to encode the rule correctly in less than 250ms. This time is close to the fastest synaptic learning speed deemed possible by diffusive influx of AMPA receptors. Learning continued at a slower pace in the delay period and was fully completed in average 900ms after rule presentation onset, when response latencies dropped to levels consistent with basic reaction times. A neural model was proposed that explains the reduction of response times and of their variability with the delay by (i) a random synaptic learning process that generates weights of average values increasing with the learning time, followed by (ii) random crossing of the firing threshold by a leaky integrate-and-fire neuron model, and (iii) assuming that the behavioural response is initiated when all neurons in a pool of m neurons have fired their first spike after input onset. Values of m=2 or 3 were consistent with the experimental data. The proposed model is the simplest solution consistent with neurophysiological knowledge. Additional experiments are suggested to test the hypothesis underlying the model and also to explore forgetting effects for which there were indications for the longer delay conditions. This article is part of a Special Issue entitled Neural Coding 2012. © 2013 Elsevier B.V. All rights reserved.

  13. Retinal metric: a stimulus distance measure derived from population neural responses.

    Science.gov (United States)

    Tkačik, Gašper; Granot-Atedgi, Einat; Segev, Ronen; Schneidman, Elad

    2013-02-01

    The ability of an organism to distinguish between various stimuli is limited by the structure and noise in the population code of its sensory neurons. Here we infer a distance measure on the stimulus space directly from the recorded activity of 100 neurons in the salamander retina. In contrast to previously used measures of stimulus similarity, this "neural metric" tells us how distinguishable a pair of stimulus clips is to the retina, based on the similarity between the induced distributions of population responses. We show that the retinal distance strongly deviates from Euclidean, or any static metric, yet has a simple structure: we identify the stimulus features that the neural population is jointly sensitive to, and show the support-vector-machine-like kernel function relating the stimulus and neural response spaces. We show that the non-Euclidean nature of the retinal distance has important consequences for neural decoding.

  14. Three-input majority logic gate and multiple input logic circuit based on DNA strand displacement.

    Science.gov (United States)

    Li, Wei; Yang, Yang; Yan, Hao; Liu, Yan

    2013-06-12

    In biomolecular programming, the properties of biomolecules such as proteins and nucleic acids are harnessed for computational purposes. The field has gained considerable attention due to the possibility of exploiting the massive parallelism that is inherent in natural systems to solve computational problems. DNA has already been used to build complex molecular circuits, where the basic building blocks are logic gates that produce single outputs from one or more logical inputs. We designed and experimentally realized a three-input majority gate based on DNA strand displacement. One of the key features of a three-input majority gate is that the three inputs have equal priority, and the output will be true if any of the two inputs are true. Our design consists of a central, circular DNA strand with three unique domains between which are identical joint sequences. Before inputs are introduced to the system, each domain and half of each joint is protected by one complementary ssDNA that displays a toehold for subsequent displacement by the corresponding input. With this design the relationship between any two domains is analogous to the relationship between inputs in a majority gate. Displacing two or more of the protection strands will expose at least one complete joint and return a true output; displacing none or only one of the protection strands will not expose a complete joint and will return a false output. Further, we designed and realized a complex five-input logic gate based on the majority gate described here. By controlling two of the five inputs the complex gate can realize every combination of OR and AND gates of the other three inputs.

  15. Misspecifications of stimulus presentation durations in experimental psychology: a systematic review of the psychophysics literature.

    Directory of Open Access Journals (Sweden)

    Tobias Elze

    Full Text Available BACKGROUND: In visual psychophysics, precise display timing, particularly for brief stimulus presentations, is often required. The aim of this study was to systematically review the commonly applied methods for the computation of stimulus durations in psychophysical experiments and to contrast them with the true luminance signals of stimuli on computer displays. METHODOLOGY/PRINCIPAL FINDINGS: In a first step, we systematically scanned the citation index Web of Science for studies with experiments with stimulus presentations for brief durations. Articles which appeared between 2003 and 2009 in three different journals were taken into account if they contained experiments with stimuli presented for less than 50 milliseconds. The 79 articles that matched these criteria were reviewed for their method of calculating stimulus durations. For those 75 studies where the method was either given or could be inferred, stimulus durations were calculated by the sum of frames (SOF method. In a second step, we describe the luminance signal properties of the two monitor technologies which were used in the reviewed studies, namely cathode ray tube (CRT and liquid crystal display (LCD monitors. We show that SOF is inappropriate for brief stimulus presentations on both of these technologies. In extreme cases, SOF specifications and true stimulus durations are even unrelated. Furthermore, the luminance signals of the two monitor technologies are so fundamentally different that the duration of briefly presented stimuli cannot be calculated by a single method for both technologies. Statistics over stimulus durations given in the reviewed studies are discussed with respect to different duration calculation methods. CONCLUSIONS/SIGNIFICANCE: The SOF method for duration specification which was clearly dominating in the reviewed studies leads to serious misspecifications particularly for brief stimulus presentations. We strongly discourage its use for brief stimulus

  16. Misspecifications of stimulus presentation durations in experimental psychology: a systematic review of the psychophysics literature.

    Science.gov (United States)

    Elze, Tobias

    2010-09-29

    In visual psychophysics, precise display timing, particularly for brief stimulus presentations, is often required. The aim of this study was to systematically review the commonly applied methods for the computation of stimulus durations in psychophysical experiments and to contrast them with the true luminance signals of stimuli on computer displays. In a first step, we systematically scanned the citation index Web of Science for studies with experiments with stimulus presentations for brief durations. Articles which appeared between 2003 and 2009 in three different journals were taken into account if they contained experiments with stimuli presented for less than 50 milliseconds. The 79 articles that matched these criteria were reviewed for their method of calculating stimulus durations. For those 75 studies where the method was either given or could be inferred, stimulus durations were calculated by the sum of frames (SOF) method. In a second step, we describe the luminance signal properties of the two monitor technologies which were used in the reviewed studies, namely cathode ray tube (CRT) and liquid crystal display (LCD) monitors. We show that SOF is inappropriate for brief stimulus presentations on both of these technologies. In extreme cases, SOF specifications and true stimulus durations are even unrelated. Furthermore, the luminance signals of the two monitor technologies are so fundamentally different that the duration of briefly presented stimuli cannot be calculated by a single method for both technologies. Statistics over stimulus durations given in the reviewed studies are discussed with respect to different duration calculation methods. The SOF method for duration specification which was clearly dominating in the reviewed studies leads to serious misspecifications particularly for brief stimulus presentations. We strongly discourage its use for brief stimulus presentations on CRT and LCD monitors.

  17. Assessing sustainable remediation frameworks using sustainability principles.

    Science.gov (United States)

    Ridsdale, D Reanne; Noble, Bram F

    2016-12-15

    The remediation industry has grown exponentially in recent decades. International organizations of practitioners and remediation experts have developed several frameworks for integrating sustainability into remediation projects; however, there has been limited attention to how sustainability is approached and operationalized in sustainable remediation frameworks and practices - or whether sustainability plays any meaningful role at all in sustainable remediation. This paper examines how sustainability is represented in remediation frameworks and the guidance provided for practical application. Seven broad sustainability principles and review criteria are proposed and applied to a sample of six international remediation frameworks. Not all review criteria were equally satisfied and none of the frameworks fully met all criteria; however, the best performing frameworks were those identified as sustainability remediation frameworks. Intra-generational equity was addressed by all frameworks. Integrating social, economic and biophysical components beyond triple-bottom-line indicators was explicitly addressed only by the sustainable remediation frameworks. No frameworks provided principle- or rule-based guidance for dealing with trade-offs in sustainability decisions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Stimulus dependence of local field potential spectra: experiment versus theory.

    Science.gov (United States)

    Barbieri, Francesca; Mazzoni, Alberto; Logothetis, Nikos K; Panzeri, Stefano; Brunel, Nicolas

    2014-10-29

    The local field potential (LFP) captures different neural processes, including integrative synaptic dynamics that cannot be observed by measuring only the spiking activity of small populations. Therefore, investigating how LFP power is modulated by external stimuli can offer important insights into sensory neural representations. However, gaining such insight requires developing data-driven computational models that can identify and disambiguate the neural contributions to the LFP. Here, we investigated how networks of excitatory and inhibitory integrate-and-fire neurons responding to time-dependent inputs can be used to interpret sensory modulations of LFP spectra. We computed analytically from such models the LFP spectra and the information that they convey about input and used these analytical expressions to fit the model to LFPs recorded in V1 of anesthetized macaques (Macaca mulatta) during the presentation of color movies. Our expressions explain 60%-98% of the variance of the LFP spectrum shape and its dependency upon movie scenes and we achieved this with realistic values for the best-fit parameters. In particular, synaptic best-fit parameters were compatible with experimental measurements and the predictions of firing rates, based only on the fit of LFP data, correlated with the multiunit spike rate recorded from the same location. Moreover, the parameters characterizing the input to the network across different movie scenes correlated with cross-scene changes of several image features. Our findings suggest that analytical descriptions of spiking neuron networks may become a crucial tool for the interpretation of field recordings. Copyright © 2014 the authors 0270-6474/14/3414589-17$15.00/0.

  19. Organizing for Sustainability

    Science.gov (United States)

    Brown, William M.; Hamburger, Michael W.

    2012-01-01

    A successful campus sustainability effort catalyzes broad engagement of the campus community and integration of sustainability principles into the academic and operational components of campus life. Although many universities have embraced sustainability as a new core value, others have been more sluggish in adopting sustainability principles to…

  20. Technology and sustainability

    NARCIS (Netherlands)

    Kroeze, C.; Boersema, J.J.; Tellegen, E.; Cremers, A.

    2011-01-01

    In ten essays, this book addresses a broad range of issues related to the interplay of sustainability and technology. How do population growth and technology relate to sustainable development? Can globalization be reconciled with sustainable development? Is sustainability a subjective or an

  1. Signaling the unconditioned stimulus during the preexposure phase does not attenuate the unconditioned stimulus preexposure effect in preweanling rats.

    Science.gov (United States)

    Castello, Stefania; Bobbio, Antonella; Orellana, Estefania; Arias, Carlos

    2012-12-01

    The unconditioned stimulus preexposure effect (US-PE) is defined as an attenuation of the conditioned response after preexposure to the US prior to conditioning. Evidence exists that this effect can be weakened or eliminated by the presence of a signal predicting the US during the preexposure phase. This evidence has been found consistently across a variety of procedures in adult rats. The aim of the present study was to evaluate whether, in infant rats, signaling the US (LiCl) during preexposure with a salient cue (almond odor) attenuates the US-PE. During the preexposure phase, preweanling rats received three (Experiment 1) or one (Experiment 2) preexposures to LiCl, preceded by exposure to almond odor. Appropriate control groups were also included in these experiments. After preexposure, two conditioning trials were carried out in which subjects were given LiCl after saccharin consumption. During preexposure, three (Experiment 1a), although not one (Experiment 2a), contingent exposures to almond odor and LiCl resulted in a strong odor aversion. Extinction of the learned taste aversion was facilitated by prior experience with LiCl (Experiments 1b and 2b). This effect was observed regardless of whether or not LiCl was signaled by the almond odor. These results do not coincide with the associative hypotheses proposed to explain the US-PE, nor are they concurrent with alternative explanations based on the learned helplessness phenomenon. Copyright © 2011 Wiley Periodicals, Inc.

  2. Mobile gaze input system for pervasive interaction

    DEFF Research Database (Denmark)

    2016-01-01

    feedback to the user in response to the received command input. The unit provides feedback to the user on how to position the mobile unit in front of his eyes. The gaze tracking unit interacts with one or more controlled devices via wireless or wired communications. Example devices include a lock...

  3. The Contrast Theory of negative input.

    Science.gov (United States)

    Saxton, M

    1997-02-01

    Beliefs about whether or not children receive corrective input for grammatical errors depend crucially on how one defines the concept of correction. Arguably, previous conceptualizations do not provide a viable basis for empirical research (Gold, 1967; Brown & Hanlon, 1970; Hirsh-Pasek, Treiman & Schneiderman, 1984). Within the Contrast Theory of negative input, an alternative definition of negative evidence is offered, based on the idea that the unique discourse structure created in the juxtaposition of child error and adult correct form can reveal to the child the contrast, or conflict, between the two forms, and hence provide a basis for rejecting the erroneous form. A within-subjects experimental design was implemented for 36 children (mean age 5;0), in order to compare the immediate effects of negative evidence with those of positive input, on the acquisition of six novel irregular past tense forms. Children reproduced the correct irregular model more often, and persisted with fewer errors, following negative evidence rather than positive input.

  4. Drawings as Input for Handheld Game Computers

    NARCIS (Netherlands)

    Poel, Mannes; Zwiers, Jakob; Nijholt, Antinus; de Jong, R.; Krooman, E.; Maybury, Mark; Stock, Oliveiro; Wahlster, Wolfgang

    2005-01-01

    The Nintendo DS (TM) is a hand held game computer that includes a small sketch pad as one of it input modalities. We discuss the possibilities for recognition of simple line drawing on this device, with focus of attention on robustness and real-time behavior. The results of our experiments show that

  5. Hydrogen Generation Rate Model Calculation Input Data

    Energy Technology Data Exchange (ETDEWEB)

    KUFAHL, M.A.

    2000-04-27

    This report documents the procedures and techniques utilized in the collection and analysis of analyte input data values in support of the flammable gas hazard safety analyses. This document represents the analyses of data current at the time of its writing and does not account for data available since then.

  6. Representations of space based on haptic input

    NARCIS (Netherlands)

    Zuidhoek, S.

    2005-01-01

    The present thesis focused on the representations of grasping space based on haptic input. We aimed at identifying their characteristics, and the underlying neurocognitive processes and mechanisms. To this end, we studied the systematic distortions in performance on several orientation perception

  7. Input and Intake in Language Acquisition

    Science.gov (United States)

    Gagliardi, Ann C.

    2012-01-01

    This dissertation presents an approach for a productive way forward in the study of language acquisition, sealing the rift between claims of an innate linguistic hypothesis space and powerful domain general statistical inference. This approach breaks language acquisition into its component parts, distinguishing the input in the environment from…

  8. Programmable Input for Nanomagnetic Logic Devices

    Directory of Open Access Journals (Sweden)

    Schmitt-Landsiedel D.

    2013-01-01

    Full Text Available A programmable magnetic input, based on the magnetic interaction of a soft and hard magnetic layer is presented for the first time. Therefore, a single-domain Co/Pt nanomagnet is placed on top of one end of a permalloy bar, separated by a thin dielectric layer. The permalloy bar of the introduced input structure is magnetized by weak easy-axis in-plane fields. Acting like a ’magnetic amplifier’, the generated fringing fields of the permalloy pole are strong enough to control the magnetization of the superimposed Co/Pt nanomagnets, which have high crystalline perpendicular magnetic anisotropy. This magnetostatic interaction results in a shift of the hysteresis curve of the Co/Pt nanomagnet, measured by magneto-optical Kerr microscopy. The Co/Pt nanomagnet is fixed by the fringing field of the permalloy and thereby not affected by the magnetic power clock of the Nanomagnetic Logic system. MFM measurements verify the functionality of the programmable magnetic input structure. The fringing fields are extracted from micromagnetic simulations and are in good agreement with experimental results. The introduced input structure enables switching the logic functionality of the majority gate from NAND to NOR during runtime, offering programmable Nanomagnetic Logic.

  9. Facilitating agricultural input distribution in Uganda - Experiences ...

    African Journals Online (AJOL)

    Mo

    2004 National Agricultural Research Organisation. Facilitating agricultural input distribution in ... guarantee fund, a retail oriented business training, farmer training, promotion, and efforts to develop the rural markets. Such interventions help .... Working in solidarity groups benefits the rural retailers in that they have stronger ...

  10. Leaders’ receptivity to subordinates’ creative input: the role of achievement goals and composition of creative input

    NARCIS (Netherlands)

    Sijbom, R.B.L.; Janssen, O.; van Yperen, N.W.

    2015-01-01

    We identified leaders’ achievement goals and composition of creative input as important factors that can clarify when and why leaders are receptive to, and supportive of, subordinates’ creative input. As hypothesized, in two experimental studies, we found that relative to mastery goal leaders,

  11. Action Research for Sustainability

    DEFF Research Database (Denmark)

    Egmose, Jonas

    by analysing processes of social learning. The book addresses the need to move towards sustainability at societal level as a democratic challenge questioning the way we live on planet earth. By conceptualising sustain-ability as an immanent and emergent ability of ecological and social life, continuously...... to renew itself without eroding its own foundation of existence, it argues that since sustainability cannot be invented but only supported (or eroded) by science, we need to reframe science in the role of sustaining sustain-ability. Through analyses of a three year action research programme, aiming...

  12. Sustainable Investment. Literature Overview

    Energy Technology Data Exchange (ETDEWEB)

    Weda, J.; Kerste, M.; Rosenboom, N.

    2010-08-15

    Corporate Social Responsibility (CSR), or sustainability at the company level, entails incorporating ecological (environmental stakeholders) and social aspects (stakeholders other than shareholders and environmental stakeholders) when doing business. Socially Responsible Investment (SRI) concerns sustainability at the investment, fund or portfolio level and involves screening the sustainability of companies before investing in them. This report highlights leading literature and empirical findings on 'sustainable investment', amongst others addressing the economic rationale for CSR and SRI. This report is part of a set of SEO-reports on finance and sustainability. The other reports deal with: Financing the Transition to Sustainable Energy; Carbon Trading; Innovations in financing environmental and social sustainability.

  13. Postnatal maturation of GABAergic modulation of sensory inputs onto lateral amygdala principal neurons.

    Science.gov (United States)

    Bosch, Daniel; Ehrlich, Ingrid

    2015-10-01

    Throughout life, fear learning is indispensable for survival and neural plasticity in the lateral amygdala underlies this learning and storage of fear memories. During development, properties of fear learning continue to change into adulthood, but currently little is known about changes in amygdala circuits that enable these behavioural transitions. In recordings from neurons in lateral amygdala brain slices from infant up to adult mice, we show that spontaneous and evoked excitatory and inhibitory synaptic transmissions mature into adolescence. At this time, increased inhibitory activity and signalling has the ability to restrict the function of excitation by presynaptic modulation, and may thus enable precise stimulus associations to limit fear generalization from adolescence onward. Our results provide a basis for addressing plasticity mechanisms that underlie altered fear behaviour in young animals. Convergent evidence suggests that plasticity in the lateral amygdala (LA) participates in acquisition and storage of fear memory. Sensory inputs from thalamic and cortical areas activate principal neurons and local GABAergic interneurons, which provide feed-forward inhibition that tightly controls LA activity and plasticity via pre- and postsynaptic GABAA and GABAB receptors. GABAergic control is also critical during fear expression, generalization and extinction in adult animals. During rodent development, properties of fear and extinction learning continue to change into early adulthood. Currently, few studies have assessed physiological changes in amygdala circuits that may enable these behavioural transitions. To obtain first insights, we investigated changes in spontaneous and sensory input-evoked inhibition onto LA principal neurons and then focused on GABAB receptor-mediated modulation of excitatory sensory inputs in infant, juvenile, adolescent and young adult mice. We found that spontaneous and sensory-evoked inhibition increased during development

  14. Stimulus-dependent effects on right ear advantage in schizophrenia

    Directory of Open Access Journals (Sweden)

    Smucny J

    2012-09-01

    Full Text Available Jason Smucny,1,3 Korey Wylie,3 Jason Tregellas1–31Neuroscience Program, University of Colorado Anschutz Medical Campus, 2Research Science, Denver VA Medical, Center, 3Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USABackground: When presented with different sounds in each ear (dichotic listening, healthy subjects typically show a preference for stimuli heard in the right ear, an effect termed "right ear advantage". Previous studies examining right ear advantage in schizophrenia have been inconsistent, showing either decreased or increased advantage relative to comparison subjects. Given evidence for enhanced semantic processing in schizophrenia, some of this inconsistency may be due to the type of stimuli presented (words or syllables. The present study examined right ear advantage in patients and controls using both words and syllables as stimuli.Methods: Right ear advantage was compared between 20 patients with schizophrenia and 17 healthy controls. Two versions of the task were used, ie, a consonant-vowel pairing task and a fused rhymed words task.Results: A significant group × task interaction was observed. Relative to healthy controls, patients showed a greater difference on the syllable-based task compared with the word-based task. The number of distractors marked during the syllable-based task was inversely correlated with score on the Global Assessment of Function Scale.Conclusion: The findings are consistent with a left hemisphere dysfunction in schizophrenia, but also suggest that differences may be stimulus-specific, with a relative sparing of the deficit in the context of word stimuli. Performance may be related to measures of social, occupational, and psychological function.Keywords: schizophrenia, right ear advantage, dichotic, distraction

  15. Perceived control increases the reward positivity and stimulus preceding negativity.

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    Mühlberger, Christina; Angus, Douglas Jozef; Jonas, Eva; Harmon-Jones, Cindy; Harmon-Jones, Eddie

    2017-02-01

    The reward positivity (RewP) and the stimulus preceding negativity (SPN), two ERPs associated with reward delivery and reward anticipation, are modulated by motivational intensity. Motivational intensity is the effort organisms would make to exert behaviors, and it varies with the difficulty of exerting that behavior. If a task is perceived as impossible, which means that one does not have control over own outcomes, motivational intensity is low. In the current study, we tested the prediction that perceiving control over one's outcomes increases both the RewP to feedback and the SPN prior to feedback compared to perceiving no control. We also examined whether P300 and LPP amplitudes to reward and nonreward images were similarly modulated. Twenty-five female participants completed a gambling task in which correct choices were followed by pictures of attractive men and incorrect choices were followed by pictures of rocks. To manipulate perceived control, participants were told that, in one block of trials, they could learn a mouse-click rule in order to see only pictures of men (high perceived control condition), while in the other block, the pictures would appear randomly (low perceived control condition). However, in both conditions, feedback appeared randomly. Although the RewP was elicited in both blocks, the RewP and SPN were higher in the high perceived control condition (i.e., when participants thought that they could influence their outcomes). Perceived control did not modulate the P300 and LPP to pictures. The results suggest that approach motivation and its intensity modulate the processing of performance feedback. © 2016 Society for Psychophysiological Research.

  16. A computational study of stimulus driven epileptic seizure abatement.

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    Peter Neal Taylor

    Full Text Available Active brain stimulation to abate epileptic seizures has shown mixed success. In spike-wave (SW seizures, where the seizure and background state were proposed to coexist, single-pulse stimulations have been suggested to be able to terminate the seizure prematurely. However, several factors can impact success in such a bistable setting. The factors contributing to this have not been fully investigated on a theoretical and mechanistic basis. Our aim is to elucidate mechanisms that influence the success of single-pulse stimulation in noise-induced SW seizures. In this work, we study a neural population model of SW seizures that allows the reconstruction of the basin of attraction of the background activity as a four dimensional geometric object. For the deterministic (noise-free case, we show how the success of response to stimuli depends on the amplitude and phase of the SW cycle, in addition to the direction of the stimulus in state space. In the case of spontaneous noise-induced seizures, the basin becomes probabilistic introducing some degree of uncertainty to the stimulation outcome while maintaining qualitative features of the noise-free case. Additionally, due to the different time scales involved in SW generation, there is substantial variation between SW cycles, implying that there may not be a fixed set of optimal stimulation parameters for SW seizures. In contrast, the model suggests an adaptive approach to find optimal stimulation parameters patient-specifically, based on real-time estimation of the position in state space. We discuss how the modelling work can be exploited to rationally design a successful stimulation protocol for the abatement of SW seizures using real-time SW detection.

  17. Tectorial membrane morphological variation: effects upon stimulus frequency otoacoustic emissions.

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    Bergevin, Christopher; Velenovsky, David S; Bonine, Kevin E

    2010-08-09

    The tectorial membrane (TM) is widely believed to play an important role in determining the ear's ability to detect and resolve incoming acoustic information. While it is still unclear precisely what that role is, the TM has been hypothesized to help overcome viscous forces and thereby sharpen mechanical tuning of the sensory cells. Lizards present a unique opportunity to further study the role of the TM given the diverse inner-ear morphological differences across species. Furthermore, stimulus-frequency otoacoustic emissions (SFOAEs), sounds emitted by the ear in response to a tone, noninvasively probe the frequency selectivity of the ear. We report estimates of auditory tuning derived from SFOAEs for 12 different species of lizards with widely varying TM morphology. Despite gross anatomical differences across the species examined herein, low-level SFOAEs were readily measurable in all ears tested, even in non-TM species whose basilar papilla contained as few as 50-60 hair cells. Our measurements generally support theoretical predictions: longer delays/sharper tuning features are found in species with a TM relative to those without. However, SFOAEs from at least one non-TM species (Anolis) with long delays suggest there are likely additional micromechanical factors at play that can directly affect tuning. Additionally, in the one species examined with a continuous TM (Aspidoscelis) where cell-to-cell coupling is presumably relatively stronger, delays were intermediate. This observation appears consistent with recent reports that suggest the TM may play a more complex macromechanical role in the mammalian cochlea via longitudinal energy distribution (and thereby affect tuning). Although significant differences exist between reptilian and mammalian auditory biophysics, understanding lizard OAE generation mechanisms yields significant insight into fundamental principles at work in all vertebrate ears. 2010 Biophysical Society. Published by Elsevier Inc. All rights

  18. Stimulus-dependent spiking relationships with the EEG

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    Snyder, Adam C.

    2015-01-01

    The development and refinement of noninvasive techniques for imaging neural activity is of paramount importance for human neuroscience. Currently, the most accessible and popular technique is electroencephalography (EEG). However, nearly all of what we know about the neural events that underlie EEG signals is based on inference, because of the dearth of studies that have simultaneously paired EEG recordings with direct recordings of single neurons. From the perspective of electrophysiologists there is growing interest in understanding how spiking activity coordinates with large-scale cortical networks. Evidence from recordings at both scales highlights that sensory neurons operate in very distinct states during spontaneous and visually evoked activity, which appear to form extremes in a continuum of coordination in neural networks. We hypothesized that individual neurons have idiosyncratic relationships to large-scale network activity indexed by EEG signals, owing to the neurons' distinct computational roles within the local circuitry. We tested this by recording neuronal populations in visual area V4 of rhesus macaques while we simultaneously recorded EEG. We found substantial heterogeneity in the timing and strength of spike-EEG relationships and that these relationships became more diverse during visual stimulation compared with the spontaneous state. The visual stimulus apparently shifts V4 neurons from a state in which they are relatively uniformly embedded in large-scale network activity to a state in which their distinct roles within the local population are more prominent, suggesting that the specific way in which individual neurons relate to EEG signals may hold clues regarding their computational roles. PMID:26108954

  19. Putative mechanisms mediating tolerance for audiovisual stimulus onset asynchrony.

    Science.gov (United States)

    Bhat, Jyoti; Miller, Lee M; Pitt, Mark A; Shahin, Antoine J

    2015-03-01

    Audiovisual (AV) speech perception is robust to temporal asynchronies between visual and auditory stimuli. We investigated the neural mechanisms that facilitate tolerance for audiovisual stimulus onset asynchrony (AVOA) with EEG. Individuals were presented with AV words that were asynchronous in onsets of voice and mouth movement and judged whether they were synchronous or not. Behaviorally, individuals tolerated (perceived as synchronous) longer AVOAs when mouth movement preceded the speech (V-A) stimuli than when the speech preceded mouth movement (A-V). Neurophysiologically, the P1-N1-P2 auditory evoked potentials (AEPs), time-locked to sound onsets and known to arise in and surrounding the primary auditory cortex (PAC), were smaller for the in-sync than the out-of-sync percepts. Spectral power of oscillatory activity in the beta band (14-30 Hz) following the AEPs was larger during the in-sync than out-of-sync perception for both A-V and V-A conditions. However, alpha power (8-14 Hz), also following AEPs, was larger for the in-sync than out-of-sync percepts only in the V-A condition. These results demonstrate that AVOA tolerance is enhanced by inhibiting low-level auditory activity (e.g., AEPs representing generators in and surrounding PAC) that code for acoustic onsets. By reducing sensitivity to acoustic onsets, visual-to-auditory onset mapping is weakened, allowing for greater AVOA tolerance. In contrast, beta and alpha results suggest the involvement of higher-level neural processes that may code for language cues (phonetic, lexical), selective attention, and binding of AV percepts, allowing for wider neural windows of temporal integration, i.e., greater AVOA tolerance. Copyright © 2015 the American Physiological Society.

  20. Accommodative response/stimulus by dynamic retinoscopy: near add guidelines.

    Science.gov (United States)

    Goss, David A; Rana, Sania; Ramolia, Julie

    2012-10-01

    Monocular estimation method (MEM) dynamic retinoscopy and low neutral (LN) dynamic retinoscopy are common procedures for evaluating the need for near-point plus adds for improved near-point performance in non-presbyopes. A combination of MEM and LN has been suggested to be a method of plotting accommodative response/accommodative stimulus functions and evaluating guidelines for prescribing from MEM. Using a combined MEM-LN procedure, MEM was performed on 80 young adults at 40 cm, with distance correction and with plus adds in 0.25 D steps up to and including +2.00 D. Modified Thorington dissociated phorias were also performed with each of the plus adds. Subjects picked a preferred add, which subjectively made print easiest and most comfortable to read. The mean preferred add was +0.58 D over the distance prescription. The add derived from subtracting 0.25 D from the lag of accommodation with distance correction averaged 0.10 D more plus than the preferred add. The add at which dynamic retinoscopy showed a "with" motion of 0.25 D averaged 0.54 more plus than the preferred add. The add at which dynamic retinoscopy showed a "with" motion of 0.50 D averaged 0.16 more plus than the preferred add. Adds derived from subtracting 0.25 D from the lag with distance correction and from finding the add that yields 0.50 D of "with" motion compared favorably with the preferred adds on average, but the standard deviations of the differences were high. Those guidelines could be reasonable starting points for the prescription of near-point plus adds for non-presbyopes, but follow-up testing to confirm or adjust add power would be advisable in the clinical setting.

  1. Visual Distractors Disrupt Audiovisual Integration Regardless of Stimulus Complexity

    Science.gov (United States)

    Gibney, Kyla D.; Aligbe, Enimielen; Eggleston, Brady A.; Nunes, Sarah R.; Kerkhoff, Willa G.; Dean, Cassandra L.; Kwakye, Leslie D.

    2017-01-01

    The intricate relationship between multisensory integration and attention has been extensively researched in the multisensory field; however, the necessity of attention for the binding of multisensory stimuli remains contested. In the current study, we investigated whether diverting attention from well-known multisensory tasks would disrupt integration and whether the complexity of the stimulus and task modulated this interaction. A secondary objective of this study was to investigate individual differences in the interaction of attention and multisensory integration. Participants completed a simple audiovisual speeded detection task and McGurk task under various perceptual load conditions: no load (multisensory task while visual distractors present), low load (multisensory task while detecting the presence of a yellow letter in the visual distractors), and high load (multisensory task while detecting the presence of a number in the visual distractors). Consistent with prior studies, we found that increased perceptual load led to decreased reports of the McGurk illusion, thus confirming the necessity of attention for the integration of speech stimuli. Although increased perceptual load led to longer response times for all stimuli in the speeded detection task, participants responded faster on multisensory trials than unisensory trials. However, the increase in multisensory response times violated the race model for no and low perceptual load conditions only. Additionally, a geometric measure of Miller’s inequality showed a decrease in multisensory integration for the speeded detection task with increasing perceptual load. Surprisingly, we found diverging changes in multisensory integration with increasing load for participants who did not show integration for the no load condition: no changes in integration for the McGurk task with increasing load but increases in integration for the detection task. The results of this study indicate that attention plays a

  2. Stimulus size dependence of information transfer from retina to thalamus

    Directory of Open Access Journals (Sweden)

    Robert Uglesich

    2009-10-01

    Full Text Available Relay cells in the mammalian lateral geniculate nucleus (LGN are driven primarily by single retinal ganglion cells (RGCs. However, an LGN cell responds typically to less than half of the spikes it receives from the RGC that drives it, and without retinal drive the LGN is silent (Kaplan and Shapley, 1984. Recent studies, which used stimuli restricted to the receptive field (RF center, show that despite the great loss of spikes, more than half of the information carried by the RGC discharge is typically preserved in the LGN discharge (Sincich et al., 2009, suggesting that the retinal spikes that are deleted by the LGN carry less information than those that are transmitted to the cortex. To determine how LGN relay neurons decide which retinal spikes to respond to, we recorded extracellularly from the cat LGN the LGN spikes together with the slow synaptic (‘S’ potentials that signal the firing of retinal spikes. We investigated the influence of the inhibitory surround of the LGN RF by stimulating the eyes with spots of various sizes, the largest of which covered the center and surround of the LGN relay cell’s RF. We found that for stimuli that activated mostly the RF center, each LGN spike delivered more information than the retinal spike, but this difference was reduced as stimulus size increased to cover the RF surround. To evaluate the optimality of the LGN editing of retinal spikes, we created artificial spike trains from the retinal ones by various deletion schemes. We found that single LGN cells transmitted less information than an optimal detector could.

  3. Auditory sustained field responses to periodic noise

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    Keceli Sumru

    2012-01-01

    Full Text Available Abstract Background Auditory sustained responses have been recently suggested to reflect neural processing of speech sounds in the auditory cortex. As periodic fluctuations below the pitch range are important for speech perception, it is necessary to investigate how low frequency periodic sounds are processed in the human auditory cortex. Auditory sustained responses have been shown to be sensitive to temporal regularity but the relationship between the amplitudes of auditory evoked sustained responses and the repetitive rates of auditory inputs remains elusive. As the temporal and spectral features of sounds enhance different components of sustained responses, previous studies with click trains and vowel stimuli presented diverging results. In order to investigate the effect of repetition rate on cortical responses, we analyzed the auditory sustained fields evoked by periodic and aperiodic noises using magnetoencephalography. Results Sustained fields were elicited by white noise and repeating frozen noise stimuli with repetition rates of 5-, 10-, 50-, 200- and 500 Hz. The sustained field amplitudes were significantly larger for all the periodic stimuli than for white noise. Although the sustained field amplitudes showed a rising and falling pattern within the repetition rate range, the response amplitudes to 5 Hz repetition rate were significantly larger than to 500 Hz. Conclusions The enhanced sustained field responses to periodic noises show that cortical sensitivity to periodic sounds is maintained for a wide range of repetition rates. Persistence of periodicity sensitivity below the pitch range suggests that in addition to processing the fundamental frequency of voice, sustained field generators can also resolve low frequency temporal modulations in speech envelope.

  4. Engineering crop nutrient efficiency for sustainable agriculture.

    Science.gov (United States)

    Chen, Liyu; Liao, Hong

    2017-10-01

    Increasing crop yields can provide food, animal feed, bioenergy feedstocks and biomaterials to meet increasing global demand; however, the methods used to increase yield can negatively affect sustainability. For example, application of excess fertilizer can generate and maintain high yields but also increases input costs and contributes to environmental damage through eutrophication, soil acidification and air pollution. Improving crop nutrient efficiency can improve agricultural sustainability by increasing yield while decreasing input costs and harmful environmental effects. Here, we review the mechanisms of nutrient efficiency (primarily for nitrogen, phosphorus, potassium and iron) and breeding strategies for improving this trait, along with the role of regulation of gene expression in enhancing crop nutrient efficiency to increase yields. We focus on the importance of root system architecture to improve nutrient acquisition efficiency, as well as the contributions of mineral translocation, remobilization and metabolic efficiency to nutrient utilization efficiency. © 2017 Institute of Botany, Chinese Academy of Sciences.

  5. Intrinsic properties of and thalamocortical inputs onto identified corticothalamic-VPM neurons.

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    Yang, Qizong; Chen, Chia-Chien; Ramos, Raddy L; Katz, Elizabeth; Keller, Asaf; Brumberg, Joshua C

    2014-06-01

    Corticothalamic (CT) feedback plays an important role in regulating the sensory information that the cortex receives. Within the somatosensory cortex layer VI originates the feedback to the ventral posterior medial (VPM) nucleus of the thalamus, which in turn receives sensory information from the contralateral whiskers. We examined the physiology and morphology of CT neurons in rat somatosensory cortex, focusing on the physiological characteristics of the monosynaptic inputs that they receive from the thalamus. To identify CT neurons, rhodamine microspheres were injected into VPM and allowed to retrogradely transport to the soma of CT neurons. Thalamocortical slices were prepared at least 3 days post injection. Whole-cell recordings from labeled CT cells in layer VI demonstrated that they are regular spiking neurons and exhibit little spike frequency adaption. Two anatomical classes were identified based on their apical dendrites that either terminated by layer V (compact cells) or layer IV (elaborate cells). Thalamic inputs onto identified CT-VPM neurons demonstrated paired pulse depression over a wide frequency range (2-20 Hz). Stimulus trains also resulted in significant synaptic depression above 10 Hz. Our results suggest that thalamic inputs differentially impact CT-VPM neurons in layer VI. This characteristic may allow them to differentiate a wide range of stimulation frequencies which in turn further tune the feedback signals to the thalamus.

  6. Integration of tactile input across fingers in a patient with finger agnosia.

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    Anema, Helen A; Overvliet, Krista E; Smeets, Jeroen B J; Brenner, Eli; Dijkerman, H Chris

    2011-01-01

    Finger agnosia has been described as an inability to explicitly individuate between the fingers, which is possibly due to fused neural representations of these fingers. Hence, are patients with finger agnosia unable to keep tactile information perceived over several fingers separate? Here, we tested a finger agnosic patient (GO) on two tasks that measured the ability to keep tactile information simultaneously perceived by individual fingers separate. In experiment 1 GO performed a haptic search task, in which a target (the absence of a protruded line) needed to be identified among distracters (protruded lines). The lines were presented simultaneously to the fingertips of both hands. Similarly to the controls, her reaction time decreased when her fingers were aligned as compared to when her fingers were stretched and in an unaligned position. This suggests that she can keep tactile input from different fingers separate. In experiment two, GO was required to judge the position of a target tactile stimulus to the index finger, relatively to a reference tactile stimulus to the middle finger, both in fingers uncrossed and crossed position. GO was able to indicate the relative position of the target stimulus as well as healthy controls, which indicates that she was able to keep tactile information perceived by two neighbouring fingers separate. Interestingly, GO performed better as compared to the healthy controls in the finger crossed condition. Together, these results suggest the GO is able to implicitly distinguish between tactile information perceived by multiple fingers. We therefore conclude that finger agnosia is not caused by minor disruptions of low-level somatosensory processing. These findings further underpin the idea of a selective impaired higher order body representation restricted to the fingers as underlying cause of finger agnosia. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Understanding and reducing complex systems pharmacology models based on a novel input-response index.

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    Knöchel, Jane; Kloft, Charlotte; Huisinga, Wilhelm

    2018-02-01

    A growing understanding of complex processes in biology has led to large-scale mechanistic models of pharmacologically relevant processes. These models are increasingly used to study the response of the system to a given input or stimulus, e.g., after drug administration. Understanding the input-response relationship, however, is often a challenging task due to the complexity of the interactions between its constituents as well as the size of the models. An approach that quantifies the importance of the different constituents for a given input-output relationship and allows to reduce the dynamics to its essential features is therefore highly desirable. In this article, we present a novel state- and time-dependent quantity called the input-response index that quantifies the importance of state variables for a given input-response relationship at a particular time. It is based on the concept of time-bounded controllability and observability, and defined with respect to a reference dynamics. In application to the brown snake venom-fibrinogen (Fg) network, the input-response indices give insight into the coordinated action of specific coagulation factors and about those factors that contribute only little to the response. We demonstrate how the indices can be used to reduce large-scale models in a two-step procedure: (i) elimination of states whose dynamics have only minor impact on the input-response relationship, and (ii) proper lumping of the remaining (lower order) model. In application to the brown snake venom-fibrinogen network, this resulted in a reduction from 62 to 8 state variables in the first step, and a further reduction to 5 state variables in the second step. We further illustrate that the sequence, in which a recursive algorithm eliminates and/or lumps state variables, has an impact on the final reduced model. The input-response indices are particularly suited to determine an informed sequence, since they are based on the dynamics of the original system

  8. The Effect of Monaural Auditory Stimulus on Hand Selection When Reaching.

    Science.gov (United States)

    Tani, Keisuke; Jono, Yasutomo; Nomura, Yoshifumi; Chujo, Yuta; Hiraoka, Koichi

    2017-07-01

    This study investigated the effect of monaural auditory stimulus on hand selection when reaching. Healthy right-handed participants were asked to reach to a visual target and were free to use either the right or left hand. A visual target appeared at one of 11 positions in the visual field between -25 and 25 degrees of the horizontal visual angle. An auditory stimulus was given either in the left or right ear 100 ms after the presentation of the visual target, or no auditory stimulus was given. An auditory stimulus in the right ear increased right hand selection, and that in the left ear slightly increased left hand selection when reaching to a target around the midline of the visual field. The horizontal visual angle, where the probabilities of right hand selection and left hand selection were equal when reaching, shifted leftward when an auditory stimulus was given in the right ear, but the angle did not shift in either direction when an auditory stimulus was given in the left ear. The right-ear-dominant auditory stimulus effect on hand selection indicates hemispheric asymmetry of cortical activity for hand selection.

  9. Comparing different stimulus configurations for population receptive field mapping in human fMRI

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    Ivan eAlvarez

    2015-02-01

    Full Text Available Population receptive field (pRF mapping is a widely used approach to measuring aggregate human visual receptive field properties by recording non-invasive signals using functional MRI. Despite growing interest, no study to date has systematically investigated the effects of different stimulus configurations on pRF estimates from human visual cortex. Here we compared the effects of three different stimulus configurations on a model-based approach to pRF estimation: size-invariant bars and eccentricity-scaled bars defined in Cartesian coordinates and traveling along the cardinal axes, and a novel simultaneous ‘wedge and ring’ stimulus defined in polar coordinates, systematically covering polar and eccentricity axes. We found that the presence or absence of eccentricity scaling had a significant effect on goodness of fit and pRF size estimates. Further, variability in pRF size estimates was directly influenced by stimulus configuration, particularly for higher visual areas including V5/MT+. Finally, we compared eccentricity estimation between phase-encoded and model-based pRF approaches. We observed a tendency for more peripheral eccentricity estimates using phase-encoded methods, independent of stimulus size. We conclude that both eccentricity scaling and polar rather than Cartesian stimulus configuration are important considerations for optimal experimental design in pRF mapping. While all stimulus configurations produce adequate estimates, simultaneous wedge and ring stimulation produced higher fit reliability, with a significant advantage in reduced acquisition time.

  10. Spatially specific versus unspecific disruption of visual orientation perception using chronometric pre-stimulus TMS

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    Tom Alexander De Graaf

    2015-01-01

    Full Text Available Transcranial magnetic stimulation (TMS over occipital cortex can impair visual processing. Such ‘TMS masking’ has repeatedly been shown at several stimulus onset asynchronies (SOAs, with TMS pulses generally applied after the onset of a visual stimulus. Following increased interest in the neuronal state-dependency of visual processing, we recently explored the efficacy of TMS at ‘negative SOAs’, when no visual processing can yet occur. We could reveal pre-stimulus TMS disruption, with results moreover hinting at two separate mechanisms in occipital cortex biasing subsequent orientation perception. Here we extended this work, including a chronometric design to map the temporal dynamics of spatially specific and unspecific mechanisms of state-dependent visual processing, while moreover controlling for TMS-induced pupil covering. TMS pulses applied 60-40 ms prior to a visual stimulus decreased orientation processing independent of stimulus location, while a local suppressive effect was found for TMS applied 30-10 ms pre-stimulus. These results contribute to our understanding of spatiotemporal mechanisms in occipital cortex underlying the state-dependency of visual processing, providing a basis for future work to link pre-stimulus TMS suppression effects to other known visual biasing mechanisms.

  11. Spatially specific vs. unspecific disruption of visual orientation perception using chronometric pre-stimulus TMS

    Science.gov (United States)

    de Graaf, Tom A.; Duecker, Felix; Fernholz, Martin H. P.; Sack, Alexander T.

    2015-01-01

    Transcranial magnetic stimulation (TMS) over occipital cortex can impair visual processing. Such “TMS masking” has repeatedly been shown at several stimulus onset asynchronies (SOAs), with TMS pulses generally applied after the onset of a visual stimulus. Following increased interest in the neuronal state-dependency of visual processing, we recently explored the efficacy of TMS at “negative SOAs”, when no visual processing can yet occur. We could reveal pre-stimulus TMS disruption, with results moreover hinting at two separate mechanisms in occipital cortex biasing subsequent orientation perception. Here we extended this work, including a chronometric design to map the temporal dynamics of spatially specific and unspecific mechanisms of state-dependent visual processing, while moreover controlling for TMS-induced pupil covering. TMS pulses applied 60–40 ms prior to a visual stimulus decreased orientation processing independent of stimulus location, while a local suppressive effect was found for TMS applied 30–10 ms pre-stimulus. These results contribute to our understanding of spatiotemporal mechanisms in occipital cortex underlying the state-dependency of visual processing, providing a basis for future work to link pre-stimulus TMS suppression effects to other known visual biasing mechanisms. PMID:25688194

  12. Social conformity is due to biased stimulus processing: electrophysiological and diffusion analyses.

    Science.gov (United States)

    Germar, Markus; Albrecht, Thorsten; Voss, Andreas; Mojzisch, Andreas

    2016-09-01

    Hundreds of studies have found that humans' decisions are strongly influenced by the opinions of others, even when making simple perceptual decisions. In this study, we aimed to clarify whether this effect can be explained by social influence biasing (early) perceptual processes. We employed stimulus evoked potentials, lateralized readiness potentials (LRPs) and a diffusion model analysis of reaction time data to uncover the neurocognitive processes underlying social conformity in perceptual decision-making. The diffusion model analysis showed that social conformity was due to a biased uptake of stimulus information and accompanied by more careful stimulus processing. As indicated by larger N1-amplitudes, social influence increased early attentional resources for stimulus identification and discrimination. Furthermore, LRP analyses revealed that stimulus processing was biased even in cases of non-conformity. In conclusion, our results suggest that the opinion of others can cause individuals to selectively process stimulus information supporting this opinion, thereby inducing social conformity. This effect is present even when individuals do not blindly follow the majority but rather carefully process stimulus information. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  13. Enhanced stimulus-induced gamma activity in humans during propofol-induced sedation.

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    Neeraj Saxena

    Full Text Available Stimulus-induced gamma oscillations in the 30-80 Hz range have been implicated in a wide number of functions including visual processing, memory and attention. While occipital gamma-band oscillations can be pharmacologically modified in animal preparations, pharmacological modulation of stimulus-induced visual gamma oscillations has yet to be demonstrated in non-invasive human recordings. Here, in fifteen healthy humans volunteers, we probed the effects of the GABAA agonist and sedative propofol on stimulus-related gamma activity recorded with magnetoencephalography, using a simple visual grating stimulus designed to elicit gamma oscillations in the primary visual cortex. During propofol sedation as compared to the normal awake state, a significant 60% increase in stimulus-induced gamma amplitude was seen together with a 94% enhancement of stimulus-induced alpha suppression and a simultaneous reduction in the amplitude of the pattern-onset evoked response. These data demonstrate, that propofol-induced sedation is accompanied by increased stimulus-induced gamma activity providing a potential window into mechanisms of gamma-oscillation generation in humans.

  14. Stimulus devaluation induced by action stopping is greater for explicit value representations

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    Jan R Wessel

    2015-10-01

    Full Text Available We recently showed that rapidly stopping an action in the face of a reward-related stimulus reduces the subjective value of that stimulus (Wessel et al., 2014. In that study, there were three phases. In an initial learning phase, geometric shapes were associated with monetary value via implicit learning. In a subsequent treatment phase, half the shapes were paired with action-stopping, and half were not. In a final auction phase, shapes that had been paired with stopping in the treatment phase were subjectively perceived as less valuable compared to those that were not. Exploratory post-hoc analysis showed that the stopping-induced devaluation effect was larger for participants with greater explicit knowledge of stimulus values. Here, we repeated the study in 65 participants to systematically test whether the level of explicit knowledge influences the degree of devaluation. The results replicated the core result that action-stopping reduces stimulus value. Furthermore, they showed that this effect was indeed significantly larger in participants with more explicit knowledge of the relative stimulus values in the learning phase. These results speak to the robustness of the stopping-induced devaluation effect, and furthermore imply that behavioral therapies using stopping could be successful in devaluing real-world stimuli, insofar as stimulus values are explicitly represented. Finally, to facilitate future investigations into the applicability of these findings as well as the mechanisms underlying stopping-induced stimulus devaluation, we herein provide open source code for the behavioral paradigm.

  15. Report to Congress on Sustainable Ranges, 2011

    Science.gov (United States)

    2011-07-01

    Services (IGI&S) data proponency, Common Installation Picture, and Quality Assurance Plans ( QAPs ). Based on this guidance, all Army installations are...Sustainable Ranges Report July 2011 Support Center are defined in each layer’s geospatial data QAP . QAPs provide the definition, information about the...requirements for each of the data layers. QAPs are living documents and are maintained by the HQDA proponent with input from the installation data

  16. The impact of subliminal effect images in voluntary vs. stimulus-driven actions.

    Science.gov (United States)

    Le Bars, Solène; Hsu, Yi-Fang; Waszak, Florian

    2016-11-01

    According to the ideomotor theory, actions are represented in terms of their sensory effects. In the current study we tested whether subliminal effect images influence action control (1) at early and/or late preparatory stages of (2) voluntary actions or stimulus-driven actions (3) with or without Stimulus-Response (S-R) compatibility. In Experiment 1, participants were presented at random with 50% of S-R compatible stimulus-driven action trials and 50% of voluntary action trials. The actions' effects (i.e. up- or down-pointing arrows) were presented subliminally before each action (i.e. a keypress). In voluntary actions, participants selected more often the action congruent with the prime when it was presented at long intervals before the action. Moreover they responded faster in prime-congruent than in prime-incongruent trials when primes were presented at short intervals before the action. In Experiment 2, participants were only presented with stimulus-driven action trials, with or without S-R compatibility. In stimulus-driven action trials with S-R compatibility (e.g., left-pointing arrow signaling a left keypress), subliminal action-effects did not generate any significant effect on RTs or error rates. On the other hand, in stimulus-driven action trials without S-R compatibility (e.g., letter "H" signaling a left keypress), participants were significantly faster in prime-congruent trials when primes were presented at the shortest time interval before the action. These results suggest that subliminal effect images facilitate voluntary action preparation on an early and a late level. Stimulus-driven action preparation is influenced on a late level only, and only if there is no compatibility between the stimulus and the motor response, that is when the response is not automatically triggered by the common properties existing between the stimulus and the required action. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Missing mass approximations for the partition function of stimulus driven Ising models.

    Science.gov (United States)

    Haslinger, Robert; Ba, Demba; Galuske, Ralf; Williams, Ziv; Pipa, Gordon

    2013-01-01

    Ising models are routinely used to quantify the second order, functional structure of neural populations. With some recent exceptions, they generally do not include the influence of time varying stimulus drive. Yet if the dynamics of network function are to be understood, time varying stimuli must be taken into account. Inclusion of stimulus drive carries a heavy computational burden because the partition function becomes stimulus dependent and must be separately calculated for all unique stimuli observed. This potentially increases computation time by the length of the data set. Here we present an extremely fast, yet simply implemented, method for approximating the stimulus dependent partition function in minutes or seconds. Noting that the most probable spike patterns (which are few) occur in the training data, we sum partition function terms corresponding to those patterns explicitly. We then approximate the sum over the remaining patterns (which are improbable, but many) by casting it in terms of the stimulus modulated missing mass (total stimulus dependent probability of all patterns not observed in the training data). We use a product of conditioned logistic regression models to approximate the stimulus modulated missing mass. This method has complexity of roughly O(LNNpat) where is L the data length, N the number of neurons and N pat the number of unique patterns in the data, contrasting with the O(L2 (N) ) complexity of alternate methods. Using multiple unit recordings from rat hippocampus, macaque DLPFC and cat Area 18 we demonstrate our method requires orders of magnitude less computation time than Monte Carlo methods and can approximate the stimulus driven partition function more accurately than either Monte Carlo methods or deterministic approximations. This advance allows stimuli to be easily included in Ising models making them suitable for studying population based stimulus encoding.

  18. Missing Mass Approximations for the Partition Function of Stimulus Driven Ising Models

    Directory of Open Access Journals (Sweden)

    Robert eHaslinger

    2013-07-01

    Full Text Available Ising models are routinely used to quantify the second order, functional structure of neural populations. With some recent exceptions, they generally do not include the influence of time varying stimulus drive. Yet if the dynamics of network function are to be understood, time varying stimuli must be taken into account. Inclusion of stimulus drive carries a heavy computational burden because the partition function becomes stimulus dependent and must be separately calculated for all unique stimuli observed. This potentially increases computation time by the length of the data set. Here we present an extremely fast, yet simply implemented, method for approximating the stimulus dependent partition function in minutes or seconds. Noting that the most probable spike patterns (which are few occur in the training data, we sum partition function terms corresponding to those patterns explicitly. We then approximate the sum over the remaining patterns (which are improbable, but many by casting it in terms of the stimulus modulated missing mass (total stimulus dependent probability of all patterns not observed in the training data. We use use a product of conditioned logistic regression models to approximate the stimulus modulated missing mass. This method has complexity of roughly O(LNN_{pat} where is L the data length, N the number of neurons and N_{pat} the number of unique patterns in the data, contrasting with the O(L2^N complexity of alternate methods. Using multiple unit recordings from rat hippocampus, macaque DLPFC and cat Area 18 we demonstrate our method requires orders of magnitude less computation time than Monte Carlo methods and can approximate the stimulus driven partition function more accurately than either Monte Carlo methods or deterministic approximations. This advance allows stimuli to be easily included in Ising models making them suitable for studying population based stimulus encoding.

  19. Convergence characteristics of two algorithms in non-linear stimulus artefact cancellation for electrically evoked potential enhancement.

    Science.gov (United States)

    Parsa, V; Parker, P; Scott, R

    1998-03-01

    Somatosensory evoked potentials (SEPs) are a sub-class of evoked potentials (EPs) that are very useful in diagnosing various neuromuscular disorders and in spinal cord and peripheral-nerve monitoring. Most often, the measurements of these signals are contaminated by stimulus-evoked artefact. Conventional stimulus-artifact (SA) reduction schemes are primarily hardware-based and rely on some form of input blanking during the SA phase. This procedure can result in partial SEP loss if the tail of the SA interferes with the SEP. Adaptive filters offer an attractive solution to this problem by iteratively reducing the SA waveform while leaving the SEP intact. Owing to the inherent non-linearities in the SA generation system, non-linear adaptive filters (NAFs) are most suitable. SA reduction using NAFs based on truncated second-order Volterra expansion series is investigated. The focus is on the performance of two main adaptation algorithms, the least mean square (LMS) and recursive least squares (RLS) algorithms, in the context of non-linear adaptive filtering. A comparison between the convergence and performance characteristics of these two algorithms is made by processing both simulated and experimental SA data. It is found that, in high artefact-to-noise ratio (ANR) SA cancellation, owing to the large eigenvalue spreads, the RLS-based NAF is more efficient than the LMS-based NAF. However, in low-ANR scenarios, the RLS- and LMS-based NAFs exhibit similar convergence properties, and the computational simplicity of the LMS-based NAFs makes them the preferred option.

  20. Decomposition of BOLD Activity into Tuned and Untuned Components Reveals Cohabitation of Stimulus and Choice Information in V1

    Directory of Open Access Journals (Sweden)

    Kyoung Whan Choe

    2012-10-01

    Full Text Available Recent studies on V1 report top-down modulation of input-driven responses of sensory neurons, implying that exogenous sensory drives and endogenous top-down drives jointly determine V1 responses. By measuring fMRI responses in conjunction with a classification task on ambiguous ring stimuli, we sought to understand how V1 carries out its encoding operation on afferent currents while being adaptively modulated by top-down currents associated with perceptual tasks. Population activity of V1, as in its raw eccentricity profiles, failed to resolve the threshold differences between the ring stimuli due to large moment-to-moment fluctuations. The analysis of variance indicated that stimulus-evoked responses explain only one-fifth of the total variance and fMRI responses were highly correlated among eccentricity-bins, implying that a substantial fraction of V1 responses fluctuate as a whole. This led us to decompose the raw fMRI responses into untuned and tuned components: average response across eccentricity-bins and residual responses from the average, respectively, the former varying only in time and the latter varying in both space and time. The tuned responses revealed the veridical encoding operation of V1 by readily distinguishing between the ring stimuli, which was impossible with the raw fMRI responses. In contrast, the untuned were correlated with two major aspects of choice behavior—inter-trial variability in response time and inter-subject variability in response bias. We propose that this cohabitation of stimulus and choice information in V1 indicates the presence of top-down exertion of gain modulation on the early processing stage by the high-tier stage that accumulates evidence for perceptual choices.

  1. Action Research for Sustainability

    DEFF Research Database (Denmark)

    Egmose, Jonas

    How can action research further new research orientations towards sustainability? This book, empirically situated in the field of upstream public engagement, involving local residents, researchers and practitioners in bottom-up processes deliberating on urban sustainability, answers this question...... by analysing processes of social learning. The book addresses the need to move towards sustainability at societal level as a democratic challenge questioning the way we live on planet earth. By conceptualising sustain-ability as an immanent and emergent ability of ecological and social life, continuously...... to renew itself without eroding its own foundation of existence, it argues that since sustainability cannot be invented but only supported (or eroded) by science, we need to reframe science in the role of sustaining sustain-ability. Through analyses of a three year action research programme, aiming...

  2. Encoding of Discriminative Fear Memory by Input-Specific LTP in the Amygdala.

    Science.gov (United States)

    Kim, Woong Bin; Cho, Jun-Hyeong

    2017-08-30

    In auditory fear conditioning, experimental subjects learn to associate an auditory conditioned stimulus (CS) with an aversive unconditioned stimulus. With sufficient training, animals fear conditioned to an auditory CS show fear response to the CS, but not to irrelevant auditory stimuli. Although long-term potentiation (LTP) in the lateral amygdala (LA) plays an essential role in auditory fear conditioning, it is unknown whether LTP is induced selectively in the neural pathways conveying specific CS information to the LA in discriminative fear learning. Here, we show that postsynaptically expressed LTP is induced selectively in the CS-specific auditory pathways to the LA in a mouse model of auditory discriminative fear conditioning. Moreover, optogenetically induced depotentiation of the CS-specific auditory pathways to the LA suppressed conditioned fear responses to the CS. Our results suggest that input-specific LTP in the LA contributes to fear memory specificity, enabling adaptive fear responses only to the relevant sensory cue. VIDEO ABSTRACT. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Occipitoparietal contributions to recognition memory: stimulus encoding prompted by verbal instructions and operant contingencies

    Directory of Open Access Journals (Sweden)

    Schlund Michael W

    2007-08-01

    Full Text Available Abstract Background Many human neuroimaging investigations on recognition memory employ verbal instructions to direct subject's attention to a stimulus attribute. But do the same or a similar neurophysiological process occur during nonverbal experiences, such as those involving contingency-shaped responses? Establishing the spatially distributed neural network underlying recognition memory for instructed stimuli and operant, contingency-shaped (i.e., discriminative stimuli would extend the generality of contemporary domain-general views of recognition memory and clarify the involvement of declarative memory processes in human operant behavior. Methods Fifteen healthy adults received equivalent amounts of exposure to three different stimulus sets prior to neuroimaging. Encoding of one stimulus set was prompted using instructions that emphasized memorizing stimuli (Instructed. In contrast, encoding of two additional stimulus sets was prompted using a GO/NO-GO operant task, in which contingencies shaped appropriate GO and NO-GO responding. During BOLD functional MRI, subjects completed two recognition tasks. One required passive viewing of stimuli. The second task required recognizing whether a presented stimulus was a GO/NO-GO stimulus, an Instructed stimulus, or novel (NEW stimulus. Retrieval success related to recognition memory was isolated by contrasting activation from each stimulus set to a novel stimulus (i.e., an OLD > NEW contrast. To explore differences potentially related to source memory, separate contrasts were performed between stimulus sets. Results No regions reached supralevel thresholds during the passive viewing task. However, a relatively similar set of regions was activated during active recognition regardless of the methods and included dorsolateral and ventrolateral prefrontal cortex, right inferior and posterior parietal regions and the occipitoparietal region, precuneus, lingual, fusiform gyri and cerebellum. Results also

  4. Evaluation of Electrical Stimulus Current Applied to Retina Cells for Retinal Prosthesis

    Science.gov (United States)

    Motonami, Keita; Watanabe, Taiichiro; Deguchi, Jun; Fukushima, Takafumi; Tomita, Hiroshi; Sugano, Eriko; Sato, Manami; Kurino, Hiroyuki; Tamai, Makoto; Koyanagi, Mitsumasa

    2006-04-01

    We have proposed a novel multilayer stacked retinal prosthesis chip based on three-dimensional integration technology. Implantable stimulus electrode arrays in polyimide flexible cables were fabricated for the electrical stimulation of the retina. To evaluate optimal retinal stimulus current, electrically evoked potential (EEP) was recorded in animal experiments using Japanese white rabbits. The EEP waveform was compared with visually evoked potential (VEP) waveform. The amplitude of the recorded EEP increased with stimulus current. The EEP waveform shows a similar behavior to the VEP waveform, indicating that the electrical stimulation of the retina can be exploited for the blind to perceive incident light to the retina.

  5. Additional support for the existence of skin conductance responses at unconditioned stimulus omission.

    Science.gov (United States)

    Spoormaker, Victor I; Blechert, Jens; Goya-Maldonado, Roberto; Sämann, Philipp G; Wilhelm, Frank H; Czisch, Michael

    2012-11-15

    The existence of a skin conductance response to an expected but omitted aversive stimulus has recently been challenged. To counter this claim, we provide a review of the literature and a temporal analysis of two independent skin conductance data sets during aversive conditioning and extinction that demonstrates a consistent and reproducible skin conductance response at omission of an anticipated aversive stimulus. The validity of this so-called unconditioned stimulus (US) omission response is relevant for skin conductance modeling in the context of neuroimaging and more generally for conditioning theory. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Sensory Synergy as Environmental Input Integration

    Directory of Open Access Journals (Sweden)

    Fady eAlnajjar

    2015-01-01

    Full Text Available The development of a method to feed proper environmental inputs back to the central nervous system (CNS remains one of the challenges in achieving natural movement when part of the body is replaced with an artificial device. Muscle synergies are widely accepted as a biologically plausible interpretation of the neural dynamics between the CNS and the muscular system. Yet the sensorineural dynamics of environmental feedback to the CNS has not been investigated in detail. In this study, we address this issue by exploring the concept of sensory synergy. In contrast to muscle synergy, we hypothesize that sensory synergy plays an essential role in integrating the overall environmental inputs to provide low-dimensional information to the CNS. We assume that sensor synergy and muscle synergy communicate using these low-dimensional signals. To examine our hypothesis, we conducted posture control experiments involving lateral disturbance with 9 healthy participants. Proprioceptive information represented by the changes on muscle lengths were estimated by using the musculoskeletal model analysis software SIMM. Changes on muscles lengths were then used to compute sensory synergies. The experimental results indicate that the environmental inputs were translated into the two dimensional signals and used to move the upper limb to the desired position immediately after the lateral disturbance. Participants who showed high skill in posture control were found to be likely to have a strong correlation between sensory and muscle signaling as well as high coordination between the utilized sensory synergies. These results suggest the importance of integrating environmental inputs into suitable low-dimensional signals before providing them to the CNS. This mechanism should be essential when designing the prosthesis’ sensory system to make the controller simpler

  7. Load Estimation from Natural input Modal Analysis

    OpenAIRE

    Aenlle, Manuel López; Brincker, Rune; Canteli, Alfonso Fernández

    2005-01-01

    One application of Natural Input Modal Analysis consists in estimating the unknown load acting on structures such as wind loads, wave loads, traffic loads, etc. In this paper, a procedure to determine loading from a truncated modal model, as well as the results of an experimental testing programme, are presented. The method involves the inversion of the FRF matrix partly solving the numerical problems that appear because of the truncation of the modal space. However, the error in the load est...

  8. Input Impedance of the Microstrip SQUID Amplifier

    Science.gov (United States)

    Kinion, Darin; Clarke, John

    2008-03-01

    We present measurements of the complex scattering parameters of microstrip SQUID amplifiers (MSA) cooled to 4.2 K. The input of the MSA is a microstrip transmission line in the shape of a square spiral coil surrounding the hole in the SQUID washer that serves as the ground plane. The input impedance is found by measuring the reverse scattering parameter (S11) and is described well by a low-loss transmission line model. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the resonant frequency, characteristic impedance and attenuation factor. Using this equivalent RLC circuit, we model the MSA and input network with a lumped circuit model that accurately predicts the observed gain given by the forward scattering parameter (S21). We will summarize results for different coil geometries and terminations as well as SQUID bias conditions. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344 and by Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

  9. Molecular structure input on the web

    Directory of Open Access Journals (Sweden)

    Ertl Peter

    2010-02-01

    Full Text Available Abstract A molecule editor, that is program for input and editing of molecules, is an indispensable part of every cheminformatics or molecular processing system. This review focuses on a special type of molecule editors, namely those that are used for molecule structure input on the web. Scientific computing is now moving more and more in the direction of web services and cloud computing, with servers scattered all around the Internet. Thus a web browser has become the universal scientific user interface, and a tool to edit molecules directly within the web browser is essential. The review covers a history of web-based structure input, starting with simple text entry boxes and early molecule editors based on clickable maps, before moving to the current situation dominated by Java applets. One typical example - the popular JME Molecule Editor - will be described in more detail. Modern Ajax server-side molecule editors are also presented. And finally, the possible future direction of web-based molecule editing, based on technologies like JavaScript and Flash, is discussed.

  10. Emowars: Interactive Game Input Menggunakan Ekspresi Wajah

    Directory of Open Access Journals (Sweden)

    Andry Chowanda

    2013-12-01

    Full Text Available Research in the affective game has received attention from the research communities over this lustrum. As a crucial aspect of a game, emotions play an important role in user experience as well as to emphasize the user’s emotions state on game design. This will improve the user’s interactivity while they playing the game. This research aims to discuss and analyze whether emotions can replace traditional user game inputs (keyboard, mouse, and others. The methodology used in this research is divided into two main phases: game design and facial expression recognition. The results of this research indicate that users preferred to use a traditional input such as mouse. Moreover, user’s interactivities with game are still slightly low. However, this is a great opportunity for researchers in affective game with a more interactive game play as well as rich and complex story. Hopefully this will improve the user affective state and emotions in game. The results of this research imply that happy emotion obtains 78% of detection, meanwhile the anger emotion has the lowest detection of44.4%. Moreover, users prefer mouse and FER (face expression recognition as the best input for this game.

  11. Sustaining Rural Communities through Sustainable Agriculture.

    Science.gov (United States)

    Ikerd, John

    A 5-year collaborative project between Missouri, Michigan State, and Nebraska Universities to provide new opportunities for rural community self-development through sustainable agriculture had mixed results. This happened because community members did not understand the principles of sustainability, and because the extension education system was…

  12. Efficacy of a new charge-balanced biphasic electrical stimulus in the isolated sciatic nerve and the hippocampal slice

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Ramekers, D.; Martens, H.C.F.; Wadman, W.J.

    2013-01-01

    Most deep brain stimulators apply rectangular monophasic voltage pulses. By modifying the stimulus shape, it is possible to optimize stimulus efficacy and find the best compromise between clinical effect, minimal side effects and power consumption of the stimulus generator. In this study, we

  13. Sustainable Marketing : The Importance of Being a Sustainable Business

    OpenAIRE

    Reutlinger, Janina

    2012-01-01

    This thesis deals with sustainable marketing, as well as the necessity for more sustainability. The purpose of this thesis was to determine the importance of sustainable marketing for companies. The theoretical part is divided into sustainability and sustainable marketing. Sustainability covers current issues and sustainable development, which form a background for a better understanding of sustainable marketing. Sustainable marketing includes a definition of the concept, as well as susta...

  14. Comparison of EEG and MEG in source localization of induced human gamma-band oscillations during visual stimulus.

    Science.gov (United States)

    Mideksa, K G; Hoogenboom, N; Hellriegel, H; Krause, H; Schnitzler, A; Deuschl, G; Raethjen, J; Heute, U; Muthuraman, M

    2015-08-01

    High frequency gamma oscillations are indications of information processing in cortical neuronal networks. Recently, non-invasive detection of these oscillations have become one of the main research areas in magnetoencephalography (MEG) and electroencephalography (EEG) studies. The aim of this study, which is a continuation of our previous MEG study, is to compare the capability of the two modalities (EEG and MEG) in localizing the source of the induced gamma activity due to a visual stimulus, using a spatial filtering technique known as dynamic imaging of coherent sources (DICS). To do this, the brain activity was recorded using simultaneous MEG and EEG measurement and the data were analyzed with respect to time, frequency, and location of the strongest response. The spherical head modeling technique, such as, the three-shell concentric spheres and an overlapping sphere (local sphere) have been used as a forward model to calculate the external electromagnetic potentials and fields recorded by the EEG and MEG, respectively. Our results from the time-frequency analysis, at the sensor level, revealed that the parieto-occipital electrodes and sensors from both modalities showed a clear and sustained gamma-band activity throughout the post-stimulus duration and that both modalities showed similar strongest gamma-band peaks. It was difficult to interpret the spatial pattern of the gamma-band oscillatory response on the scalp, at the sensor level, for both modalities. However, the source analysis result revealed that MEG3 sensor type, which measure the derivative along the longitude, showed the source more focally and close to the visual cortex (cuneus) as compared to that of the EEG.

  15. Dyslexic adults can learn from repeated stimulus presentation but have difficulties in excluding external noise.

    Directory of Open Access Journals (Sweden)

    Rachel L Beattie

    Full Text Available We examined whether the characteristic impairments of dyslexia are due to a deficit in excluding external noise or a deficit in taking advantage of repeated stimulus presentation. We compared non-impaired adults and adults with poor reading performance on a visual letter detection task that varied two aspects: the presence or absence of background visual noise, and a small or large stimulus set. There was no interaction between group and stimulus set size, indicating that the poor readers took advantage of repeated stimulus presentation as well as the non-impaired readers. The poor readers had higher thresholds than non-impaired readers in the presence of high external noise, but not in the absence of external noise. The results support the hypothesis that an external noise exclusion deficit, not a perceptual anchoring deficit, impairs reading for adults.

  16. Termination of Reentrant Propagation by a Single Extracellular Stimulus in an Atrial Ring Model

    National Research Council Canada - National Science Library

    Johnson, C

    2001-01-01

    .... We developed a one-dimensional mathematical model to find the probability that a short, randomly-timed extracellular stimulus would terminate reentry and to study the mechanisms responsible for termination...

  17. Possible effects of organelle charge and density on cell metabolism. [chemical response to gravitational stimulus

    Science.gov (United States)

    Bandurski, Robert S.; Schulze, Aga; Domagalski, W.

    1986-01-01

    A system of perception and transduction involving the gravity-induced asymmetric distribution of a plant growth hormone is studied. A theory is constructed which assumes that the perception of the gravitational stimulus involved a perturbation of the plant's bioelectric field and that the transduction of the stimulus involved voltage-gating of hormone movement from the plant's vascular tissue into the hormone responsive growing tissue. Particular attention is focused on the barriers to indole-3-acetic acid (IAA) transport from the seed to the mesocotyl cortex, the protoinhibition of IAA movement from the endosperm to the shoot, the effects of the gravitational stimulus on the movement of IAA from the kernel to the shoot, electrochemical gating as a target for the gravity stimulus, and the gravity sensing mechanism.

  18. Stimulus-responsive polymers and other functional polymer surfaces as components in glass microfluidic channels

    NARCIS (Netherlands)

    Kieviet, B.D.; Schön, Peter Manfred; Vancso, Gyula J.

    2014-01-01

    The integration of smart stimulus-responsive polymers as functional elements within microfluidic devices has greatly improved the performance capabilities of controlled fluid delivery. For their use as actuators in microfluidic systems, reversible expansion and shrinking are unique mechanisms which

  19. Action Research for Sustainability

    DEFF Research Database (Denmark)

    Egmose, Jonas

    Analysing processes of social learning this work addresses how action research can further new research orientations towards sustainability. Empirically situated in the field of upstream public engagement, involving local residents, researchers and practitioners in bottom-up processes deliberating...... on urban sustainability the need to move towards sustainability at societal level is conceptualised as a democratic challenge questioning the way we live on planet earth. By understanding sustainability as an immanent and emergent ability of ecological and social life, continuously to renew itself without...... eroding its own foundation of existence, it argues that since sustainability cannot be invented but only supported (or eroded) by science, we need to reframe science in the role of sustaining sustain-ability. Through analyses of a three year action research programme, aiming to provide local citizens...

  20. Handbook of sustainable engineering

    CERN Document Server

    Lee, Kun-Mo

    2013-01-01

    "The efficient utilization of energy, sustainable use of natural resources, and large-scale adoption of sustainable technologies is the key to a sustainable future. The Handbook of Sustainable Engineering provides tools that will help us achieve these goals". Nobel Prize Winner Dr. R.K. Pauchauri, Chairman, UN Intergovernmental Panel on Climate Change As global society confronts the challenges of diminishing resources, ecological degradation, and climate change, engineers play a crucial role designing and building technologies and products that fulfil our needs for utility and sustainability. The Handbook of Sustainable Engineering equips readers with the context and the best practices derived from both academic research and practical examples of successful implementations of sustainable technical solutions. The handbook’s content revolves around the two themes, new ways of thinking and new business models, including sustainable production, products, service systems and consumption while addressing key asse...

  1. FORUM: Is Ecotourism Sustainable?

    Science.gov (United States)

    Wall

    1997-07-01

    / It is legitimate to ask whether and in what form tourism might contribute to sustainable development. This is not the same as sustainable tourism which, as a single-sector approach to development, may overlook important linkages with other sectors. If tourism is to contribute to sustainable development, then it must be economically viable, ecologically sensitive and culturally appropriate. Ecotourism is often advocated as being a sustainable form of tourism but imprecision in terminology clouds basic issues and there are strong economic, ecological, and cultural reasons for believing that, even in its purest forms, ecotourism is likely to present substantial challenges to destination areas, particularly if it competes for scarce resources and displaces existing uses and users. Sustainable tourism and ecotourism are not synonyms, many forms of ecotourism may not be sustainable, and if ecotourism is to contribute to sustainable development, then careful planning and management will be required.KEY WORDS: Ecotourism; Sustainable development; Development; Tourism

  2. Livestock biodiversity and sustainability

    NARCIS (Netherlands)

    Hoffmann, I.

    2011-01-01

    Sustainable development equally includes environmental protection including biodiversity, economic growth and social equity, both within and between generations. The paper first reviews different aspects related to the sustainable use of livestock biodiversity and property regimes that influence

  3. Sustainable Public Bids

    Directory of Open Access Journals (Sweden)

    Gil César Costa de Paula

    2016-06-01

    Full Text Available In this article we will discuss the issue of sustainability in public procurement, given that the government in Brazil is constituted as a great promoter of economic development and needs to adapt its acquisitions worldwide sustainability agenda.

  4. 42 CFR 460.138 - Committees with community input.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Committees with community input. 460.138 Section... community input. A PACE organization must establish one or more committees, with community input, to do the... implementation of, and results from, the quality assessment and performance improvement plan. (c) Provide input...

  5. Indicators for environmental sustainability

    DEFF Research Database (Denmark)

    Dong, Yan; Hauschild, Michael Zwicky

    2017-01-01

    . In this study, we reviewed indicators applied in life cycle assessment (LCA), planetary boundary framework (PB), and Sustainable Development Goals (SDGs) developed under United Nation. The aim is to 1) identify their applications and relevant decision context; 2) Review their indicators and categorize them......Decision making on sustainable consumption and production requires scientifically based information on sustainability. Different environmental sustainability targets exist for specific decision problems. To observe how well these targets are met, relevant environmental indicators are needed...

  6. Effects of stimulus characteristics and sex of subject on perceived emotion.

    Science.gov (United States)

    Cutler, G H; Gilgen, A R; Gilpin, A R

    1985-08-01

    To determine the influence of pupil size, eye size, sex of stimulus face, and sex of subject on perceived emotion, 308 college students filled in missing features on stimulus faces. Each face was independently rated by two male judges on a continuum of negative to positive emotion. Analysis indicated that sex of subject was the only variable to affect perceived emotion. Women (n = 175) tended to draw faces that were judged to be more positive than faces drawn by men (n = 133).

  7. The modulation of simple reaction time by the spatial probability of a visual stimulus

    Directory of Open Access Journals (Sweden)

    Carreiro L.R.R.

    2003-01-01

    Full Text Available Simple reaction time (SRT in response to visual stimuli can be influenced by many stimulus features. The speed and accuracy with which observers respond to a visual stimulus may be improved by prior knowledge about the stimulus location, which can be obtained by manipulating the spatial probability of the stimulus. However, when higher spatial probability is achieved by holding constant the stimulus location throughout successive trials, the resulting improvement in performance can also be due to local sensory facilitation caused by the recurrent spatial location of a visual target (position priming. The main objective of the present investigation was to quantitatively evaluate the modulation of SRT by the spatial probability structure of a visual stimulus. In two experiments the volunteers had to respond as quickly as possible to the visual target presented on a computer screen by pressing an optic key with the index finger of the dominant hand. Experiment 1 (N = 14 investigated how SRT changed as a function of both the different levels of spatial probability and the subject's explicit knowledge about the precise probability structure of visual stimulation. We found a gradual decrease in SRT with increasing spatial probability of a visual target regardless of the observer's previous knowledge concerning the spatial probability of the stimulus. Error rates, below 2%, were independent of the spatial probability structure of the visual stimulus, suggesting the absence of a speed-accuracy trade-off. Experiment 2 (N = 12 examined whether changes in SRT in response to a spatially recurrent visual target might be accounted for simply by sensory and temporally local facilitation. The findings indicated that the decrease in SRT brought about by a spatially recurrent target was associated with its spatial predictability, and could not be accounted for solely in terms of sensory priming.

  8. Functional relations modulate the responsiveness to affordances despite the impact of conflicting stimulus-response mappings

    OpenAIRE

    Vastano, Roberta; Finn, Martin; Barnes-Holmes, Patrick Michael Dermot

    2017-01-01

    The study investigated how conflicting stimulus-response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent-inconsistent stimulus-response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could fu...

  9. Isomorphism Between Estes’ Stimulus Fluctuation Model and a Physical- Chemical System

    Directory of Open Access Journals (Sweden)

    Makoto Yamaguchi

    2013-10-01

    Full Text Available Although Estes’ Stimulus Sampling Theory has almost completely lost its influence, its theoretical framework has not been disproved. Particularly, one theory in that framework, Stimulus Fluctuation Model, is still important because it explains spontaneous recovery. In this short note, the process of the theory is shown to be isomorphic to the diffusion of solution between compartments. Envisioning the theory as diffusion will make it appear less artificial and suggest natural extensions.

  10. Effects of explicit cueing and ambiguity on the anticipation and experience of a painful thermal stimulus.

    Directory of Open Access Journals (Sweden)

    Lincoln M Tracy

    Full Text Available Many factors can influence the way in which we perceive painful events and noxious stimuli, but less is known about how pain perception is altered by explicit knowledge about the impending sensation. This study aimed to investigate the impact of explicit cueing on anxiety, arousal, and pain experience during the anticipation and delivery of noxious thermal heat stimulations. Fifty-two healthy volunteers were randomised to receive explicit instructions about visual cue-stimulus temperature pairings, or no explicit instructions about the cue-stimulus pairs. A pain anxiety task was used to investigate the effects of explicit cueing on anticipatory anxiety, pain experience and electrophysiological responses. Participants who received explicit instructions about the cue-stimulus pairs (i.e., the relationship between the colour of the cue and the temperature of the associated stimuli reported significantly higher subjective anxiety prior to the delivery of the thermal heat stimuli (p = .025, partial eta squared = .10. There were no effects of explicit cueing on subsequent pain intensity, unpleasantness, or the electrophysiological response to stimulus delivery. The perceived intensity and unpleasantness of the stimuli decreased across the blocks of the paradigm. In both groups anticipating the ambiguous cue elicited the largest change in electrophysiological arousal, indicating that not knowing the impending stimulus temperature led to increased arousal, compared to being certain of receiving a high temperature thermal stimulus (both p < .001. Perceived stimulus intensity varied between ambiguous and non-ambiguous cues, depending on the temperature of the stimulus. Together these findings highlight the impact and importance of explicit cueing and uncertainty in experimental pain studies, and how these factors influence the way healthy individuals perceive and react to noxious and innocuous thermal stimuli.

  11. Stimulus and correlation matching measurement technique in computer based characterization testing

    OpenAIRE

    Dorman, A M

    2012-01-01

    Constructive theory of characterization test is considered. The theory is applicable to a nano devices characterization: current-voltage, Auger current dependence. Generally small response of device under test on an applied stimulus is masked by an unknown deterministic background and a random noise. Characterization test in this signal corruption scenario should be based on correlation measurement technique of device response on applied optimal stimulus with optimal reference signal. Co-synt...

  12. Sustainable Learning Organizations

    Science.gov (United States)

    Velazquez, Luis E.; Esquer, Javier; Munguia, Nora E.; Moure-Eraso, Rafael

    2011-01-01

    Purpose: The purpose of this paper is to debate how companies may better become a sustainable learning organization by offering the most used and insightful concepts of sustainability. Design/methodology/approach: Through literature review, learning organization and sustainability perspectives are explored and compared. Findings: Learning…

  13. Measuring Educational Sustainability

    Science.gov (United States)

    Selvanathan, Rani G.

    2013-01-01

    There are many definitions that are attributable to the meaning of sustainability. Sustainability can be viewed as long-lasting, effective result of a project, venture, action, or investment without consuming additional future resources. Because of the wide nature of its applicability, a universal measure of sustainability is hard to come by. This…

  14. ORNL Annual Sustainability Report

    Energy Technology Data Exchange (ETDEWEB)

    Lapsa, Melissa Voss [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nichols, Teresa A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-02-01

    As described in this report, we have made substantial progress across the 25 roadmaps of the Sustainable Campus Initiative. The report also outlines our plans to continue integrating sustainable practices into the planning, execution, and evaluation of all ORNL activities. We appreciate your interest in our journey to sustainability, and we welcome your comments, questions, and suggestions.

  15. Toward sustainable logistics

    NARCIS (Netherlands)

    Soysal, Mehmet; Bloemhof-Ruwaard, Jacqueline M.

    2017-01-01

    The fast evolution of sustainability leads to the development of a new fast-growing concept called sustainable logistics management. This research addresses recent business trends and challenges in logistics and their implications for sustainable logistics management. Additionally, we discuss policy

  16. LCA and Sustainability

    DEFF Research Database (Denmark)

    Moltesen, Andreas; Bjørn, Anders

    2017-01-01

    LCA is often presented as a sustainability assessment tool. This chapter analyses the relationship between LCA and sustainability. This is done by first outlining the history of the sustainability concept, which gained momentum with the Brundtland Commission’s report ‘Our Common Future report ’ i...

  17. Lean maturity, lean sustainability

    DEFF Research Database (Denmark)

    Jørgensen, Frances; Matthiesen, Rikke; Nielsen, Jacob

    2007-01-01

    Although lean is rapidly growing in popularity, its implementation is far from problem free and companies may experience difficulties sustaining long term success. In this paper, it is suggested that sustainable lean requires attention to both performance improvement and capability development...... that support lean capability development and consequently, lean sustainability....

  18. Food sustainability: diverging interpretations

    NARCIS (Netherlands)

    Aiking, H.; de Boer, J.

    2004-01-01

    The concept of sustainability in general and food sustainability, in particular, entails many aspects and many interpretations. During a conference on food sustainability a broad, multidisciplinary picture was painted and many key issues were dealt with, from ecology, economy and society. In

  19. Transferring Education for Sustainability

    Science.gov (United States)

    Gafoor, Kunnathodi Abdul; Umer Farooque, T. K.

    2013-01-01

    Sustainability stands for sustaining the past, meeting needs of the present without compromising the ability to meet future needs. It should meet the individual and social needs, present and future needs local and global needs. A sustainable education that meets this requirements surely be a transferable education; an education that transfers from…

  20. Sustainability in logistics practice

    NARCIS (Netherlands)

    Hans-Heinrich Glöckner; Reinder Pieters; Stef Weijers

    2009-01-01

    This conceptual paper wants to emphasis the use of the concept of sustainability within logistics and especially transportation. While working on a new tool to help companies develop sustainable European networks, we discovered that we want to use a specific concept of sustainability: People, planet

  1. Food security and sustainable intensification.

    Science.gov (United States)

    Godfray, H Charles J; Garnett, Tara

    2014-04-05

    The coming decades are likely to see increasing pressures on the global food system, both on the demand side from increasing population and per capita consumption, and on the supply side from greater competition for inputs and from climate change. This paper argues that the magnitude of the challenge is such that action is needed throughout the food system, on moderating demand, reducing waste, improving governance and producing more food. It discusses in detail the last component, arguing that more food should be produced using sustainable intensification (SI) strategies, and explores the rationale behind, and meaning of, this term. It also investigates how SI may interact with other food policy agendas, in particular, land use and biodiversity, animal welfare and human nutrition.

  2. Global drivers, sustainable manufacturing and systems ergonomics.

    Science.gov (United States)

    Siemieniuch, C E; Sinclair, M A; Henshaw, M J deC

    2015-11-01

    This paper briefly explores the expected impact of the 'Global Drivers' (such as population demographics, food security; energy security; community security and safety), and the role of sustainability engineering in mitigating the potential effects of these Global Drivers. The message of the paper is that sustainability requires a significant input from Ergonomics/Human Factors, but the profession needs some expansion in its thinking in order to make this contribution. Creating a future sustainable world in which people experience an acceptable way of life will not happen without a large input from manufacturing industry into all the Global Drivers, both in delivering products that meet sustainability criteria (such as durability, reliability, minimised material requirement and low energy consumption), and in developing sustainable processes to deliver products for sustainability (such as minimum waste, minimum emissions and low energy consumption). Appropriate changes are already being implemented in manufacturing industry, including new business models, new jobs and new skills. Considerable high-level planning around the world is in progress and is bringing about these changes; for example, there is the US 'Advanced Manufacturing National Program' (AMNP)', the German 'Industrie 4.0' plan, the French plan 'la nouvelle France industrielle' and the UK Foresight publications on the 'Future of Manufacturing'. All of these activities recognise the central part that humans will continue to play in the new manufacturing paradigms; however, they do not discuss many of the issues that systems ergonomics professionals acknowledge. This paper discusses a number of these issues, highlighting the need for some new thinking and knowledge capture by systems ergonomics professionals. Among these are ethical issues, job content and skills issues. Towards the end, there is a summary of knowledge extensions considered necessary in order that systems ergonomists can be fully

  3. [Stimulus set and response set in task switching: a comparison using ERP].

    Science.gov (United States)

    Umebayashi, Kaoru; Okita, Tsunetaka

    2008-12-01

    Event-related potential (ERP) and reaction time (RT) were recorded to investigate the time course of processes involved in set switching. The cued set-switching paradigm required participants to switch stimulus task sets between male and female face-images memorized as targets prior to a trial block and response task sets between two stimulus-response mappings for each stimulus task. Replicating previous findings, an RT switch-cost was found when compared with set-repeat trials. The RT was also prolonged for a stimulus task requirement of memory comparison with two-face targets rather than one face. A similar prolongation with memory comparison was observed in P3b latency, which showed no switch effect. The switch effect was observed for the onset latency of stimulus-locked lateralized readiness potential (LRP), measured as an index of commencement of motor processes after response selection. The response-locked LRP indicated that the final process of motor execution itself was not modified by set switching. The processes producing the stimulus-locked LRP switch cost, associated with response task set, were discussed in terms of two hypotheses, exogenous reconfiguration and carryover.

  4. Learning to fear a second-order stimulus following vicarious learning.

    Science.gov (United States)

    Reynolds, Gemma; Field, Andy P; Askew, Chris

    2017-04-01

    Vicarious fear learning refers to the acquisition of fear via observation of the fearful responses of others. The present study aims to extend current knowledge by exploring whether second-order vicarious fear learning can be demonstrated in children. That is, whether vicariously learnt fear responses for one stimulus can be elicited in a second stimulus associated with that initial stimulus. Results demonstrated that children's (5-11 years) fear responses for marsupials and caterpillars increased when they were seen with fearful faces compared to no faces. Additionally, the results indicated a second-order effect in which fear-related learning occurred for other animals seen together with the fear-paired animal, even though the animals were never observed with fearful faces themselves. Overall, the findings indicate that for children in this age group vicariously learnt fear-related responses for one stimulus can subsequently be observed for a second stimulus without it being experienced in a fear-related vicarious learning event. These findings may help to explain why some individuals do not recall involvement of a traumatic learning episode in the development of their fear of a specific stimulus.

  5. The effect of stimulus strength on the speed and accuracy of a perceptual decision.

    Science.gov (United States)

    Palmer, John; Huk, Alexander C; Shadlen, Michael N

    2005-05-02

    Both the speed and the accuracy of a perceptual judgment depend on the strength of the sensory stimulation. When stimulus strength is high, accuracy is high and response time is fast; when stimulus strength is low, accuracy is low and response time is slow. Although the psychometric function is well established as a tool for analyzing the relationship between accuracy and stimulus strength, the corresponding chronometric function for the relationship between response time and stimulus strength has not received as much consideration. In this article, we describe a theory of perceptual decision making based on a diffusion model. In it, a decision is based on the additive accumulation of sensory evidence over time to a bound. Combined with simple scaling assumptions, the proportional-rate and power-rate diffusion models predict simple analytic expressions for both the chronometric and psychometric functions. In a series of psychophysical experiments, we show that this theory accounts for response time and accuracy as a function of both stimulus strength and speed-accuracy instructions. In particular, the results demonstrate a close coupling between response time and accuracy. The theory is also shown to subsume the predictions of Piéron's Law, a power function dependence of response time on stimulus strength. The theory's analytic chronometric function allows one to extend theories of accuracy to response time.

  6. THE VALENCY OF STIMULUS IN RUSSIAN PSYCH-VERBS: SEMANTICS-SYNTAX INTERFACE

    Directory of Open Access Journals (Sweden)

    Valentina Ju. Apresjan

    2015-01-01

    Full Text Available The paper considers semantics—syntax interface in the domain of Russian psychverbs denoting emotional states. It attempts to demonstrate that syntactic properties of psych-verbs are semantically motivated. Psych-verbs are usually assigned two thematic roles — Experiencer and Stimulus. While Experiencer in Russian psych-verbs denoting state is usually coded as nominative or dative, Stimulus lacks a standard syntactic expression. The paper puts forward a hypothesis that variation in syntactic expression is semantically motivated. It is explained by the absence of a holistic role in place of Stimulus. The types of emotional stimuli vary greatly in different emotion clusters (anger, joy, sadness, pride, fear etc. and these ontological differences receive semantic and syntactic reflection. In different emotion clusters and depending on syntactic expression, the role of Stimulus can be semantically flavored by other thematic roles, such as Patient (for certain verbs of anger, Addressee (for certain verbs of joy, Place or Theme (for certain verbs of sadness, Instrument or Part (for verbs of pride and others. The choice of syntactic expression is often triggered by this additional thematic role. The types of additional roles are determined by the whole event structure, namely, the type of stimulus, wishes of the experience, the type of feeling, behavioral and speech manifestations of emotion. If a verb allows different kinds of syntactic expression of stimulus, each government pattern is associated with its own additional thematic role. 

  7. Emotional Picture and Word Processing: An fMRI Study on Effects of Stimulus Complexity

    Science.gov (United States)

    Schlochtermeier, Lorna H.; Kuchinke, Lars; Pehrs, Corinna; Urton, Karolina; Kappelhoff, Hermann; Jacobs, Arthur M.

    2013-01-01

    Neuroscientific investigations regarding aspects of emotional experiences usually focus on one stimulus modality (e.g., pictorial or verbal). Similarities and differences in the processing between the different modalities have rarely been studied directly. The comparison of verbal and pictorial emotional stimuli often reveals a processing advantage of emotional pictures in terms of larger or more pronounced emotion effects evoked by pictorial stimuli. In this study, we examined whether this picture advantage refers to general processing differences or whether it might partly be attributed to differences in visual complexity between pictures and words. We first developed a new stimulus database comprising valence and arousal ratings for more than 200 concrete objects representable in different modalities including different levels of complexity: words, phrases, pictograms, and photographs. Using fMRI we then studied the neural correlates of the processing of these emotional stimuli in a valence judgment task, in which the stimulus material was controlled for differences in emotional arousal. No superiority for the pictorial stimuli was found in terms of emotional information processing with differences between modalities being revealed mainly in perceptual processing regions. While visual complexity might partly account for previously found differences in emotional stimulus processing, the main existing processing differences are probably due to enhanced processing in modality specific perceptual regions. We would suggest that both pictures and words elicit emotional responses with no general superiority for either stimulus modality, while emotional responses to pictures are modulated by perceptual stimulus features, such as picture complexity. PMID:23409009

  8. One for all: The effect of extinction stimulus typicality on return of fear.

    Science.gov (United States)

    Scheveneels, Sara; Boddez, Yannick; Bennett, Marc Patrick; Hermans, Dirk

    2017-12-01

    During exposure therapy, patients are encouraged to approach the feared stimulus, so they can experience that this stimulus is not followed by the anticipated aversive outcome. However, patients might treat the absence of the aversive outcome as an 'exception to the rule'. This could hamper the generalization of fear reduction when the patient is confronted with similar stimuli not used in therapy. We examined the effect of providing information about the typicality of the extinction stimulus on the generalization of extinction to a new but similar stimulus. In a differential fear conditioning procedure, an animal-like figure was paired with a brief electric shock to the wrist. In a subsequent extinction phase, a different but perceptually similar animal-like figure was presented without the shock. Before testing the generalization of extinction with a third animal-like figure, participants were either instructed that the extinction stimulus was a typical or an atypical member of the animal family. The typicality instruction effectively impacted the generalization of extinction; the third animal-like figure elicited lower shock expectancies in the typical relative to the atypical group. Skin conductance data mirrored these results, but did not reach significance. These findings suggest that verbal information about stimulus typicality can be a promising adjunctive to standard exposure treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. The 5-HT1A Receptor and the Stimulus Effects of LSD in the Rat

    Science.gov (United States)

    Reissig, C.J.; Eckler, J.R.; Rabin, R.A.; Winter, J.C.

    2005-01-01

    Rationale It has been suggested that the 5-HT1A receptor plays a significant modulatory role in the stimulus effects of the indoleamine hallucinogen lysergic acid diethylamide (LSD). Objectives The present study sought to characterize the effects of several compounds with known affinity for the 5-HT1A receptor on the discriminative stimulus effects of LSD. Methods 12 Male F-344 rats were trained in a two-lever, fixed ratio10, food reinforced task with LSD (0.1 mg/kg; IP; 15 min pretreatment) as a discriminative stimulus. Combination and substitution tests with the 5-HT1A agonists, 8-OH-DPAT, buspirone, gepirone, and ipsapirone, with LSD-induced stimulus control were then performed. The effects of these 5-HT1A ligands were also tested in the presence of the selective 5-HT1A receptor antagonist, WAY-100,635 (0.3 mg/kg; SC; 30 min. pretreatment). Results In combination tests stimulus control by LSD was increased by all 5-HT1A receptor ligands with agonist properties. Similarly, in tests of antagonism, the increase in drug-appropriate responding caused by stimulation of the 5-HT1A receptor was abolished by administration of WAY-100,635. Conclusions These data, obtained using a drug discrimination model of the hallucinogenic effects of LSD, provide support for the hypothesis that the 5-HT1A receptor has a significant modulatory role in the stimulus effects of LSD. PMID:16025319

  10. The 5-HT1A receptor and the stimulus effects of LSD in the rat.

    Science.gov (United States)

    Reissig, C J; Eckler, J R; Rabin, R A; Winter, J C

    2005-10-01

    It has been suggested that the 5-HT1A receptor plays a significant modulatory role in the stimulus effects of the indoleamine hallucinogen lysergic acid diethylamide (LSD). The present study sought to characterize the effects of several compounds with known affinity for the 5-HT1A receptor on the discriminative stimulus effects of LSD. Twelve male Fischer 344 rats were trained in a two-lever, fixed-ratio (FR) 10, and food-reinforced task with LSD (0.1 mg/kg, i.p.; 15-min pretreatment) as a discriminative stimulus. Combination and substitution tests with the 5-HT(1A) agonists, 8-OH-DPAT, buspirone, gepirone, and ipsapirone, with LSD-induced stimulus control were then performed. The effects of these 5-HT1A ligands were also tested in the presence of the selective 5-HT1A receptor antagonist, WAY-100,635 (0.3 mg/kg, s.c.; 30-min pretreatment). In combination tests, stimulus control by LSD was increased by all 5-HT1A receptor ligands with agonist properties. Similarly, in tests of antagonism, the increase in drug-appropriate responding caused by stimulation of the 5-HT1A receptor was abolished by administration of WAY-100,635. These data, obtained using a drug discrimination model of the hallucinogenic effects of LSD, provide support for the hypothesis that the 5-HT1A receptor has a significant modulatory role in the stimulus effects of LSD.

  11. Further Analysis of the Predictive Effects of a Free-Operant Competing Stimulus Assessment on Stereotypy.

    Science.gov (United States)

    Brogan, Kristen M; Rapp, John T; Sennott, Lisa A; Cook, Jennifer L; Swinkels, Erin

    2017-11-01

    We conducted five experiments to evaluate the predictive validity of a free-operant competing stimulus assessment (FOCSA). In Experiment 1, we showed that each participant's repetitive behavior persisted without social consequences. In Experiment 2, we used the FOCSA to identify high-preference, low-stereotypy (HP-LS) items for 11 participants and high-preference, high-stereotypy (HP-HS) items for nine participants. To validate the results of the FOCSAs (Experiment 3), we used a three-component multiple schedule to evaluate the immediate and subsequent effects of an HP-LS stimulus, an HP-HS stimulus, or both (in separate test sequences) on each participant's stereotypy. Results of Experiment 3 showed that the FOCSA correctly predicted the immediate effect of the HP-LS stimulus for 10 of 11 participants; however, the FOCSA predictions were less accurate for the HP-HS stimulus. Results of Experiment 4 showed that a differential reinforcement of other behavior procedure in which participants earned access to the HP-LS for omitting vocal stereotypy increased all five participants' latency to engaging in stereotypy; however, clinically significant omission durations were only achieved for one participant. Experiment 5 showed that differential reinforcement of alternative behavior in which participants earned access to the HP-LS stimulus contingent upon correct responses during discrete-trial training reduced targeted and nontargeted stereotypy and increased correct academic responding for all four participants. The potential utility of the FOCSA is discussed.

  12. A tonic heat test stimulus yields a larger and more reliable conditioned pain modulation effect compared to a phasic heat test stimulus

    Directory of Open Access Journals (Sweden)

    Marie Udnesseter Lie

    2017-12-01

    Conclusion:. The present study shows that a CPM protocol with a tonic test-stimulus is preferable to a protocol with phasic test-stimuli. However, we emphasize that one should be cautious to use the CPM effect as biomarker or in clinical decision making on an individual level due to large intraindividual variability.

  13. Mechanical Stimulus-Induced Wthdrawal Behavior Increases Subsequent Pre-Stimulus Local Field Potential Power in the Rostral Anterior Cingulate Cortex in Unanesthetized Rats.

    Science.gov (United States)

    Shen, Zui; Sun, Jing; Liu, Boyi; Jiang, Yongliang; Wu, Yuanyuan; Wang, Jialing; Shao, Xiaomei; Fang, Jianqiao

    2017-03-02

    BACKGROUND The rostral anterior cingulate cortex (rACC) is important in pain expectation. Previous studies demonstrated that mechanical stimulus-induced withdrawal behaviors are spinally-mediated nocifensive reflexes in rats, but it is not known whether pain expectation is influenced by withdrawal behaviors. MATERIAL AND METHODS We reanalyzed previous mechanosensitivity measurements of 244 rats measured 5 times in succession. To study neural oscillation in the rACC, 1 recording microwire array was surgically implanted. Then, we simultaneously recorded the local field potential (LFP) of the rACC over the course of multiple withdrawal behaviors in unanesthetized rats. RESULTS From our previous withdrawal behavioral data in 244 rats, we observed that the distributions of paw withdrawal thresholds (PWTs) were denser and more concentrated after the first withdrawal behavior. Compared to the first mechanical stimulus, increased neuronal synchrony and a stronger delta band component existed in each pre-stimulus LFP in the rACC during subsequent stimuli. CONCLUSIONS Pain expectation could be involved in withdrawal behaviors, which is related to increased total power and delta band power of the subsequent pre-stimulus LFPs in the rACC.

  14. Stimulus-Food Pairings Produce Stimulus-Directed Touch Screen Responding in Cynomolgus Monkeys ("Macaca Fascicularis") with or without a Positive Response Contingency

    Science.gov (United States)

    Bullock, Christopher E.; Myers, Todd M.

    2009-01-01

    Acquisition and maintenance of touch-screen responding was examined in naive cynomolgus monkeys ("Macaca fascicularis") under automaintenance and classical conditioning arrangements. In the first condition of Experiment 1, we compared acquisition of screen touching to a randomly positioned stimulus (a gray square) that was either stationary or…

  15. Memories as bifurcations: realization by collective dynamics of spiking neurons under stochastic inputs.

    Science.gov (United States)

    Kurikawa, Tomoki; Kaneko, Kunihiko

    2015-02-01

    How the neural system proceeds from sensory stimuli to generate appropriate behaviors is a basic question that has not yet been fully answered. In contrast to the conventional viewpoint, in which the external stimulus dominantly drives the response behavior, recent studies have revealed that not only external stimuli, but also intrinsic neural dynamics, contribute to the generation of response behavior. In particular, spontaneous activity, which is neural activity without extensive external stimuli, has been found to exhibit similar patterns to those evoked by external inputs, from time to time. In order to further understand the role of this spontaneous activity on the response, we propose a viewpoint, memories-as-bifurcations, that differs from the traditional memories-as-attractors viewpoint. According to this viewpoint, memory is recalled when spontaneous neural activity is changed to an appropriate output activity upon the application of an input. After reviewing the previous rate-coding model embodying this viewpoint, we employ a model of a spiking neuron network that can embed input/output associations, and study the dynamics of collective neural activity. The organized neural activity, which matched the target pattern, is shown to be generated even under application of stochastic input, while the spontaneous activity, which apparently shows noisy dynamics, is found to exhibit selectively higher similarity with evoked activities corresponding to embedded target patterns. These results suggest that such an intrinsic structure in the spontaneous activity might play a role in generating the higher response. The relevance of these results to biological neural processing is also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Sensitivity Analysis of Selected DIVOPS Input Factors

    Science.gov (United States)

    1977-12-01

    v40. .............. o..... ....... H-3 viii CAA- TD -77-9 SENSITIVITY ANALYSIS OF SELECTED DIVOPS INPUT FACTORS CHAPTER 1 INTRODUCTION 1-1. BACKGROUND...freedom squares A 5 l,149 15,j74 7.93** S.33U, 1jj lb5,Ubb bl.17-* - 2 47,411 23,7U5 7.35**- L) Z 48,9b5 124,493 38.59** E b5b,423 1b7,711 79.2:*** F 2

  17. Input data to run Landis-II

    Science.gov (United States)

    DeJager, Nathan R.

    2017-01-01

    The data are input data files to run the forest simulation model Landis-II for Isle Royale National Park. Files include: a) Initial_Comm, which includes the location of each mapcode, b) Cohort_ages, which includes the ages for each tree species-cohort within each mapcode, c) Ecoregions, which consist of different regions of soils and climate, d) Ecoregion_codes, which define the ecoregions, and e) Species_Params, which link the potential establishment and growth rates for each species with each ecoregion.

  18. ADAPTIVE SUBOPTIMAL CONTROL OF INPUT CONSTRAINED PLANTS

    Directory of Open Access Journals (Sweden)

    Valerii Azarskov

    2011-03-01

    Full Text Available Abstract. This paper deals with adaptive regulation of a discrete-time linear time-invariant plant witharbitrary bounded disturbances whose control input is constrained to lie within certain limits. The adaptivecontrol algorithm exploits the one-step-ahead control strategy and the gradient projection type estimationprocedure using the modified dead zone. The convergence property of the estimation algorithm is shown tobe ensured. The sufficient conditions guaranteeing the global asymptotical stability and simultaneously thesuboptimality of the closed-loop systems are derived. Numerical examples and simulations are presented tosupport the theoretical results.

  19. Flexible input, dazzling output with IBM i

    CERN Document Server

    Victória-Pereira, Rafael

    2014-01-01

    Link your IBM i system to the modern business server world! This book presents easier and more flexible ways to get data into your IBM i system, along with rather surprising methods to export and present the vital business data it contains. You'll learn how to automate file transfers, seamlessly connect PC applications with your RPG programs, and much more. Input operations will become more flexible and user-proof, with self-correcting import processes and direct file transfers that require a minimum of user intervention. Also learn novel ways to present information: your DB2 data will look gr

  20. Greener Pathways to Organics and Nanomaterials: Sustainable Applications of Nano-Catalysts(South Korea)

    Science.gov (United States)

    Sustainable chemical synthetic activity involving alternate energy input, and greener reaction medium in aqueous or solvent-free conditions will be summarized for heterocyclic compounds, coupling reactions, and a variety of name reactions; these reactions are catalyzed by basic w...