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Sample records for standardized stimuli boss

  1. Bank of Standardized Stimuli (BOSS) phase II: 930 new normative photos.

    PubMed

    Brodeur, Mathieu B; Guérard, Katherine; Bouras, Maria

    2014-01-01

    Researchers have only recently started to take advantage of the developments in technology and communication for sharing data and documents. However, the exchange of experimental material has not taken advantage of this progress yet. In order to facilitate access to experimental material, the Bank of Standardized Stimuli (BOSS) project was created as a free standardized set of visual stimuli accessible to all researchers, through a normative database. The BOSS is currently the largest existing photo bank providing norms for more than 15 dimensions (e.g. familiarity, visual complexity, manipulability, etc.), making the BOSS an extremely useful research tool and a mean to homogenize scientific data worldwide. The first phase of the BOSS was completed in 2010, and contained 538 normative photos. The second phase of the BOSS project presented in this article, builds on the previous phase by adding 930 new normative photo stimuli. New categories of concepts were introduced, including animals, building infrastructures, body parts, and vehicles and the number of photos in other categories was increased. All new photos of the BOSS were normalized relative to their name, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. The availability of these norms is a precious asset that should be considered for characterizing the stimuli as a function of the requirements of research and for controlling for potential confounding effects.

  2. Bank of Standardized Stimuli (BOSS) Phase II: 930 New Normative Photos

    PubMed Central

    Brodeur, Mathieu B.; Guérard, Katherine; Bouras, Maria

    2014-01-01

    Researchers have only recently started to take advantage of the developments in technology and communication for sharing data and documents. However, the exchange of experimental material has not taken advantage of this progress yet. In order to facilitate access to experimental material, the Bank of Standardized Stimuli (BOSS) project was created as a free standardized set of visual stimuli accessible to all researchers, through a normative database. The BOSS is currently the largest existing photo bank providing norms for more than 15 dimensions (e.g. familiarity, visual complexity, manipulability, etc.), making the BOSS an extremely useful research tool and a mean to homogenize scientific data worldwide. The first phase of the BOSS was completed in 2010, and contained 538 normative photos. The second phase of the BOSS project presented in this article, builds on the previous phase by adding 930 new normative photo stimuli. New categories of concepts were introduced, including animals, building infrastructures, body parts, and vehicles and the number of photos in other categories was increased. All new photos of the BOSS were normalized relative to their name, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. The availability of these norms is a precious asset that should be considered for characterizing the stimuli as a function of the requirements of research and for controlling for potential confounding effects. PMID:25211489

  3. The bank of standardized stimuli (BOSS): comparison between French and English norms.

    PubMed

    Brodeur, Mathieu B; Kehayia, Eva; Dion-Lessard, Geneviève; Chauret, Mélissa; Montreuil, Tina; Dionne-Dostie, Emmanuelle; Lepage, Martin

    2012-12-01

    Throughout the last decades, numerous picture data sets have been developed, such as the Snodgrass and Vanderwart (1980) set, and have been normalized for variables such as name and familiarity; however, due to cultural and linguistic differences, norms can vary from one country to another. The effect due specifically to culture has already been demonstrated by comparing samples from different countries where the same language is spoken. On the other hand, it is still not clear how differences between languages may affect norms. The present study explores this issue by collecting and comparing norms on names and many other features from French Canadian speakers and English Canadian speakers living in Montreal, who thus live in similar cultural environments. Norms were collected for the photos of objects from the Bank of Standardized Stimuli (BOSS) by asking participants to name the objects, to categorize them, and to rate their familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. Names and ratings from the French speakers are available in Appendix A, available in the supplemental materials. The results show that most of the norms are comparable across linguistic groups and also that the ratings given are correlated across linguistic groups. The only significant group differences were found in viewpoint agreement and visual complexity. Overall, there was good concordance between the norms collected from French and English native speakers living in the same cultural setting.

  4. Facial expression categorization by chimpanzees using standardized stimuli.

    PubMed

    Parr, Lisa A; Waller, Bridget M; Heintz, Matthew

    2008-04-01

    The ability to recognize and accurately interpret facial expressions are critical social cognition skills in primates, yet very few studies have examined how primates discriminate these social signals and which features are the most salient. Four experiments examined chimpanzee facial expression processing using a set of standardized, prototypical stimuli created using the new ChimpFACS coding system. First, chimpanzees were found to accurately discriminate between these expressions using a computerized matching-to-sample task, and recognition was impaired for all but one expression category when they were inverted. Third, a multidimensional scaling analysis examined the perceived dissimilarity among these facial expressions revealing 2 main dimensions, the degree of mouth closure and extent of lip-puckering and retraction. Finally, subjects were asked to match each facial expression category using only individual component features. For each expression category, at least 1 component movement was more salient or representative of that expression than the others. However, these were not necessarily the only movements implicated in subject's overall pattern of errors. Therefore, similar to humans, both configuration and component movements are important during chimpanzee facial expression processing. PMID:18410196

  5. Outsourcing the Technology Boss.

    ERIC Educational Resources Information Center

    Olsen, Florence

    2003-01-01

    Describes how California's Peralta Community Colleges District decided to hire an outside company to manage its computer networks, but that problems cause it to now want a technology boss on its own staff. (EV)

  6. BOSS: context-enhanced search for biomedical objects

    PubMed Central

    2012-01-01

    Background There exist many academic search solutions and most of them can be put on either ends of spectrum: general-purpose search and domain-specific "deep" search systems. The general-purpose search systems, such as PubMed, offer flexible query interface, but churn out a list of matching documents that users have to go through the results in order to find the answers to their queries. On the other hand, the "deep" search systems, such as PPI Finder and iHOP, return the precompiled results in a structured way. Their results, however, are often found only within some predefined contexts. In order to alleviate these problems, we introduce a new search engine, BOSS, Biomedical Object Search System. Methods Unlike the conventional search systems, BOSS indexes segments, rather than documents. A segment refers to a Maximal Coherent Semantic Unit (MCSU) such as phrase, clause or sentence that is semantically coherent in the given context (e.g., biomedical objects or their relations). For a user query, BOSS finds all matching segments, identifies the objects appearing in those segments, and aggregates the segments for each object. Finally, it returns the ranked list of the objects along with their matching segments. Results The working prototype of BOSS is available at http://boss.korea.ac.kr. The current version of BOSS has indexed abstracts of more than 20 million articles published during last 16 years from 1996 to 2011 across all science disciplines. Conclusion BOSS fills the gap between either ends of the spectrum by allowing users to pose context-free queries and by returning a structured set of results. Furthermore, BOSS exhibits the characteristic of good scalability, just as with conventional document search engines, because it is designed to use a standard document-indexing model with minimal modifications. Considering the features, BOSS notches up the technological level of traditional solutions for search on biomedical information. PMID:22595092

  7. The BigBOSS Experiment

    SciTech Connect

    Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J.; Aubourg, E.; Azzaro, M.; Bailey, S.; Baltay, C.; Baugh, C.; /APC, Paris /Brookhaven /IRFU, Saclay /Marseille, CPPM /Marseille, CPT /Durham U. / /IEU, Seoul /Fermilab /IAA, Granada /IAC, La Laguna

    2011-01-01

    BigBOSS will obtain observational constraints that will bear on three of the four 'science frontier' questions identified by the Astro2010 Cosmology and Fundamental Phyics Panel of the Decadal Survey: Why is the universe accelerating; what is dark matter and what are the properties of neutrinos? Indeed, the BigBOSS project was recommended for substantial immediate R and D support the PASAG report. The second highest ground-based priority from the Astro2010 Decadal Survey was the creation of a funding line within the NSF to support a 'Mid-Scale Innovations' program, and it used BigBOSS as a 'compelling' example for support. This choice was the result of the Decadal Survey's Program Priorization panels reviewing 29 mid-scale projects and recommending BigBOSS 'very highly'.

  8. The Effects of DC Electromagnetic Stimuli in Conjunction with Standard Cryogenic Treatment of Metals

    NASA Astrophysics Data System (ADS)

    Leadlove, Kyle Leadlove; Evans, Austin; Seyfert, James; Watson, Casey R.; Paulin, Peter

    2016-03-01

    We explore modifications to the basic cryogenic procedures utilized by 300 Below Inc. to strengthen metal components. We consider the effects of adding DC electromagnetic stimuli in our efforts to further optimize the cryogenic treatment - i.e., to augment the already improved tensile strength, shear strength, thermal and electrical conductivity, etc. resulting from 300 Below Inc.'s traditional cryogenic process. We report on the wear-test performance of DC magneto-cryogenic treated samples relative to standard cryogenically treated samples and control samples.

  9. The Effects of AC Electromagnetic Stimuli in Conjunction with Standard Cryogenic Treatment of Metals

    NASA Astrophysics Data System (ADS)

    Seyfert, James; Evans, Austin; Leadlove, Kyle; Watson, Casey; Paulin, Peter; Peter Paulin Collaboration

    2016-03-01

    We explore modifications to the basic cryogenic procedures utilized by 300 Below Inc. to strengthen metal components. We consider the effects of adding AC electromagnetic stimuli in our efforts to further optimize the cryogenic treatment - i.e., to augment the already improved tensile strength, shear strength, thermal and electrical conductivity, etc. resulting from 300 Below Inc.'s traditional cryogenic process. We report on the wear-test performance of AC magneto-cryogenic treated samples relative to standard cryogenically treated samples and control samples. Replace this text with your abstract body.

  10. Battlefield Optical Surveillance System (BOSS)

    NASA Astrophysics Data System (ADS)

    Ireland, Robert J.

    1997-02-01

    The battlefield optical surveillance system (BOSS) was developed for DARPA by the U.S. Air Force's Phillips Laboratory. BOSS is a HMMWV mounted laser surveillance and deterrence system. It is intended to be used to detect and to deter potentially hostile individuals, snipers and groups of agitators. The BOSS integrates the following: (1) a thermal camera (8-12 micrometer FLIR), that detects and cues to possible targets, (2) a 45 watt, 808 nm (near IR), air- cooled laser which provides covert illumination and designation for a day/night camera to acquire said target and attain a high-resolution image using night vision equipment, and (3) a 1 watt, 532 nm (green) laser that overtly illuminates and designates the target. It also has significant deterring effects both physiological and psychological on individuals and crowds. BOSS offers the potential capability to detect snipers before the first shot is fired. Detection of optical augmentations and the thermal characteristics of a sniper allows for this early detection. The integration of BOSS with acoustic sniper detection systems are being explored.

  11. The BigBoss Experiment

    SciTech Connect

    Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J.; Aubourg, E.; Azzaro, M.; Bailey, S.; Baltay, C.; Baugh, C.; Bebek, C.; Becerril, S.; Blanton, M.; Bolton, A.; Bromley, B.; Cahn, R.; Carton, P.-H.; Cervanted-Cota, J.L.; Chu, Y.; Cortes, M.; /APC, Paris /Brookhaven /IRFU, Saclay /Marseille, CPPM /Marseille, CPT /Durham U. / /IEU, Seoul /Fermilab /IAA, Granada /IAC, La Laguna / /IAC, Mexico / / /Madrid, IFT /Marseille, Lab. Astrophys. / / /New York U. /Valencia U.

    2012-06-07

    BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy and quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response to a call for major new instrumentation and a high-impact science program for the 4-m Mayall telescope at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed spectrograph capable of taking 5000 simultaneous spectra over a wavelength range from 340 nm to 1060 nm, with a resolution R = {lambda}/{Delta}{lambda} = 3000-4800. Using data from imaging surveys that are already underway, spectroscopic targets are selected that trace the underlying dark matter distribution. In particular, targets include luminous red galaxies (LRGs) up to z = 1.0, extending the BOSS LRG survey in both redshift and survey area. To probe the universe out to even higher redshift, BigBOSS will target bright [OII] emission line galaxies (ELGs) up to z = 1.7. In total, 20 million galaxy redshifts are obtained to measure the BAO feature, trace the matter power spectrum at smaller scales, and detect redshift space distortions. BigBOSS will provide additional constraints on early dark energy and on the curvature of the universe by measuring the Ly-alpha forest in the spectra of over 600,000 2.2 < z < 3.5 quasars. BigBOSS galaxy BAO measurements combined with an analysis of the broadband power, including the Ly-alpha forest in BigBOSS quasar spectra, achieves a FOM of 395 with Planck plus Stage III priors. This FOM is based on conservative assumptions for the analysis of broad band power (k{sub max} = 0.15), and could grow to over 600 if current work allows us to push the analysis to higher wave numbers (k{sub max} = 0.3). BigBOSS will also place constraints on theories of modified gravity and inflation, and will measure the sum of neutrino masses to 0.024 eV accuracy.

  12. Problematic Alcohol Use and Mild Intellectual Disability: Standardization of Pictorial Stimuli for an Alcohol Cue Reactivity Task

    ERIC Educational Resources Information Center

    van Duijvenbode, Neomi; Didden, Robert; Bloemsaat, Gijs; Engels, Rutger C. M. E.

    2012-01-01

    The present study focused on the first step in developing a cue reactivity task for studying cognitive biases in individuals with mild to borderline intellectual disability (ID) and alcohol use-related problems: the standardization of pictorial stimuli. Participants (N = 40), both with and without a history of alcohol use-related problems and…

  13. Auditory Evoked Potentials with Different Speech Stimuli: a Comparison and Standardization of Values

    PubMed Central

    Didoné, Dayane Domeneghini; Oppitz, Sheila Jacques; Folgearini, Jordana; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

    2016-01-01

    Introduction Long Latency Auditory Evoked Potentials (LLAEP) with speech sounds has been the subject of research, as these stimuli would be ideal to check individualś detection and discrimination. Objective The objective of this study is to compare and describe the values of latency and amplitude of cortical potentials for speech stimuli in adults with normal hearing. Methods The sample population included 30 normal hearing individuals aged between 18 and 32 years old with ontological disease and auditory processing. All participants underwent LLAEP search using pairs of speech stimuli (/ba/ x /ga/, /ba/ x /da/, and /ba/ x /di/. The authors studied the LLAEP using binaural stimuli at an intensity of 75dBNPS. In total, they used 300 stimuli were used (∼60 rare and 240 frequent) to obtain the LLAEP. Individuals received guidance to count the rare stimuli. The authors analyzed latencies of potential P1, N1, P2, N2, and P300, as well as the ampleness of P300. Results The mean age of the group was approximately 23 years. The averages of cortical potentials vary according to different speech stimuli. The N2 latency was greater for /ba/ x /di/ and P300 latency was greater for /ba/ x /ga/. Considering the overall average amplitude, it ranged from 5.35 and 7.35uV for different speech stimuli. Conclusion It was possible to obtain the values of latency and amplitude for different speech stimuli. Furthermore, the N2 component showed higher latency with the / ba / x / di / stimulus and P300 for /ba/ x / ga /. PMID:27096012

  14. The BigBOSS spectrograph

    NASA Astrophysics Data System (ADS)

    Jelinsky, Patrick; Bebek, Chris; Besuner, Robert; Carton, Pierre-Henri; Edelstein, Jerry; Lampton, Michael; Levi, Michael E.; Poppett, Claire; Prieto, Eric; Schlegel, David; Sholl, Michael

    2012-09-01

    BigBOSS is a proposed ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a 14,000 square degree galaxy and quasi-stellar object redshift survey. It consists of a 5,000- fiber-positioner focal plane feeding the spectrographs. The optical fibers are separated into ten 500 fiber slit heads at the entrance of ten identical spectrographs in a thermally insulated room. Each of the ten spectrographs has a spectral resolution (λ/Δλ) between 1500 and 4000 over a wavelength range from 360 - 980 nm. Each spectrograph uses two dichroic beam splitters to separate the spectrograph into three arms. It uses volume phase holographic (VPH) gratings for high efficiency and compactness. Each arm uses a 4096x4096 15 μm pixel charge coupled device (CCD) for the detector. We describe the requirements and current design of the BigBOSS spectrograph. Design trades (e.g. refractive versus reflective) and manufacturability are also discussed.

  15. Excitation Patterns of Standard and Steered Partial Tripolar Stimuli in Cochlear Implants.

    PubMed

    Wu, Ching-Chih; Luo, Xin

    2016-04-01

    Current steering in partial tripolar (pTP) mode has been shown to improve pitch perception and spectral resolution with cochlear implants (CIs). In this mode, a fraction (σ) of the main electrode current is returned within the cochlea and steered between the basal and apical flanking electrodes (with a proportion of α and 1 - α, respectively). Pitch generally decreases when α increases from 0 to 1, although the salience of pitch change varies across CI users. This study aimed to identify the mechanism of pitch changes with pTP-mode current steering and the factors contributing to the intersubject variability in pitch-ranking sensitivity. The electrical fields were measured for steered pTP stimuli on the same main electrode with α = 0, 0.5, and 1 in five implanted ears using electrical field imaging (EFI). The related excitation patterns were also measured physiologically using evoked compound action potential (ECAP) and psychophysically using psychophysical forward masking (PFM). Consistent with the pitch-ranking results in this study, the EFI, ECAP, and PFM centroids shifted apically with increasing α. An apical shift was also observed for the PFM peak but not for the EFI or ECAP peak. The pattern width was similar with different α values within a given measure (e.g., EFI, ECAP, or PFM), but the ECAP patterns were broader than the EFI and PFM patterns, possibly because ECAP was measured with smaller σ values than EFI and PFM. The amount of pattern shift with α depended on σ (i.e., the total amount of current used for steering) but was not correlated with the pitch-ranking sensitivity across subjects. The results revealed that the pitch changes elicited by pTP-mode current steering were not only driven by the shifts of excitation centroid. PMID:26691160

  16. Do Rare Stimuli Evoke Large P3s by Being Unexpected? A Comparison of Oddball Effects Between Standard-Oddball and Prediction-Oddball Tasks

    PubMed Central

    Verleger, Rolf; Śmigasiewicz, Kamila

    2016-01-01

    The P3 component of event-related potentials increases when stimuli are rarely presented. It has been assumed that this oddball effect (rare-frequent difference) reflects the unexpectedness of rare stimuli. The assumption of unexpectedness and its link to P3 amplitude were tested here. A standard- oddball task requiring alternative key-press responses to frequent and rare stimuli was compared with an oddball-prediction task where stimuli had to be first predicted and then confirmed by key-pressing. Oddball effects in the prediction task depended on whether the frequent or the rare stimulus had been predicted. Oddball effects on P3 amplitudes and error rates in the standard oddball task closely resembled effects after frequent predictions. This corroborates the notion that these effects occur because frequent stimuli are expected and rare stimuli are unexpected. However, a closer look at the prediction task put this notion into doubt because the modifications of oddball effects on P3 by expectancies were entirely due to effects on frequent stimuli, whereas the large P3 amplitudes evoked by rare stimuli were insensitive to predictions (unlike response times and error rates). Therefore, rare stimuli cannot be said to evoke large P3 amplitudes because they are unexpected. We discuss these diverging effects of frequency and expectancy, as well as general differences between tasks, with respect to concepts and hypotheses about P3b’s function and conclude that each discussed concept or hypothesis encounters some problems, with a conception in terms of subjective relevance assigned to stimuli offering the most consistent account of these basic effects. PMID:27512527

  17. PREFACE: Stimuli Stimuli

    NASA Astrophysics Data System (ADS)

    Queisser, Hans J.

    2011-01-01

    Tributes are paid to Zhores Alferov by presenting personal anecdotes from the fields, where Alferov performed his pioneering research: masers, lasers, solar cells and heterojunctions. What a pleasure and honor to pay tribute to Zhores Alferov in this Festschrift. Member of a remarkable laboratory and originator of imaginative and useful ideas for semiconductor physics and technology; a happy birthday! I would like to use this opportunity to ramble a little about the physics of masers, lasers, heterojunctions, solar cells— all themes of such vital importance in Alferov's career—and also tangible in my own endeavors. I start out with an anecdote of a colloquium presentation in my youthful days at Göttingen. The Physics Colloquium at Göttingen University presented a serious weekly meeting. Werner Heisenberg and Carl Friedrich von Weizsäcker attended, often Wolfgang Pauli visited from Zurich; Otto Hahn always sat in the first row, on the left corner— and he smoked his cigar. I had just obtained my doctorate [1]— it was 1958, and my boss Rudolf Hilsch ordered me to contribute a colloquium talk. He hoped that I would report on color centers in alkali halides or review experiments on quenched amorphous bismuth, a surprising superconductor [2], or on my own dissertation [1], all recent results of our team. I, however, being an avid reader of the latest American physics literature, begged to differ. The English language gave me no problems because I had in 1951/52 spent a year at the University of Kansas. This experience in the friendly American Midwest provided me with a definite linguistic advantage over most of my German fellow students. I was fascinated by those very first reports on the maser, this molecular amplifier using ammonia for stimulated emission, and therefore decided, quite to the chagrin of my boss Hilsch, to choose this particular topic for a report at the Colloquium. So I went to the rostrum in the small auditorium 'Hörsaal II' and delivered a

  18. Can Agitated Behavior of Nursing Home Residents with Dementia be Prevented With the Use of Standardized Stimuli?

    PubMed Central

    Cohen-Mansfield, Jiska; Marx, Marcia S.; Dakheel-Ali, Maha; Regier, Natalie G.; Thein, Khin; Freedman, Laurence

    2010-01-01

    Objectives The objective of this paper was to assess the relative impact of different types of stimuli on agitated behaviors of nursing home residents with dementia. Design Setting/Participants Participants were 111 residents of 7 Maryland nursing homes with a diagnosis of dementia who exhibited agitation. Intervention Different types of stimuli (music, social stimuli, simulated social stimuli, and individualized stimuli based on the person’s self-identity) to prevent behavior problems. Measurements Agitation was directly observed and recorded via the Agitated Behaviors Mapping Instrument. Results All stimulus categories were associated with significantly less physical agitation than baseline observations, and all except for manipulative stimuli were associated with significantly less total agitation. Live social stimuli were associated with less agitation than music, self-identity, work, simulated social, and manipulative stimulus categories. Task and reading stimulus categories were each associated with significantly less agitation than work, simulated social, and manipulative stimulus categories. Music and self-identity stimuli were associated with less agitation than simulated social and manipulative stimuli. Conclusion Providing stimuli offers a proactive approach to preventing agitation in persons with dementia, with live social stimuli being most successful. PMID:20579167

  19. Who Wants a Woman Boss? Only Those Who Have One.

    ERIC Educational Resources Information Center

    O'Leary, Virginia E.; Ickovics, Jeannette R.

    While working women are still underrepresented in managerial, executive, and professional positions, there are increasing numbers of women occupying leadership roles. This study was conducted to examine female secretaries' evaluations of their bosses and of their jobs. Secretaries of 20 male and 20 female bosses evaluated their bosses on…

  20. Thermal resistances of solder-boss/potting compound combinations

    NASA Technical Reports Server (NTRS)

    Veilleux, E. D.

    1968-01-01

    Formulas, which can be used as a design tool, are derived to calculate the thermal resistance of solder-boss/potting compound combinations, for different depths of a solder boss, in electronic cordwood modules. Since the solder boss is the heat source, its shape and position will affect the thermal resistance of the surrounding potting compound.

  1. What if your boss really is a jerk?

    PubMed

    Tulgan, Bruce

    2011-01-01

    If you think your boss is really a jerk, first make certain that you have done everything within your power to engage in regular one-on-one conversations; help your boss spell out expectations for your performance; and then monitor, measure, and document your own performance in relation to those expectations. If that doesn't work, then figure out which type of "jerk-boss" your boss really is. This article presents strategies for dealing with each the seven most common jerk-boss scenarios. PMID:21815555

  2. What if your boss really is a jerk?

    PubMed

    Tulgan, Bruce

    2011-01-01

    If you think your boss is really a jerk, first make certain that you have done everything within your power to engage in regular one-on-one conversations; help your boss spell out expectations for your performance; and then monitor, measure, and document your own performance in relation to those expectations. If that doesn't work, then figure out which type of "jerk-boss" your boss really is. This article presents strategies for dealing with each the seven most common jerk-boss scenarios.

  3. PREFACE: Stimuli Stimuli

    NASA Astrophysics Data System (ADS)

    Queisser, Hans J.

    2011-01-01

    Tributes are paid to Zhores Alferov by presenting personal anecdotes from the fields, where Alferov performed his pioneering research: masers, lasers, solar cells and heterojunctions. What a pleasure and honor to pay tribute to Zhores Alferov in this Festschrift. Member of a remarkable laboratory and originator of imaginative and useful ideas for semiconductor physics and technology; a happy birthday! I would like to use this opportunity to ramble a little about the physics of masers, lasers, heterojunctions, solar cells— all themes of such vital importance in Alferov's career—and also tangible in my own endeavors. I start out with an anecdote of a colloquium presentation in my youthful days at Göttingen. The Physics Colloquium at Göttingen University presented a serious weekly meeting. Werner Heisenberg and Carl Friedrich von Weizsäcker attended, often Wolfgang Pauli visited from Zurich; Otto Hahn always sat in the first row, on the left corner— and he smoked his cigar. I had just obtained my doctorate [1]— it was 1958, and my boss Rudolf Hilsch ordered me to contribute a colloquium talk. He hoped that I would report on color centers in alkali halides or review experiments on quenched amorphous bismuth, a surprising superconductor [2], or on my own dissertation [1], all recent results of our team. I, however, being an avid reader of the latest American physics literature, begged to differ. The English language gave me no problems because I had in 1951/52 spent a year at the University of Kansas. This experience in the friendly American Midwest provided me with a definite linguistic advantage over most of my German fellow students. I was fascinated by those very first reports on the maser, this molecular amplifier using ammonia for stimulated emission, and therefore decided, quite to the chagrin of my boss Hilsch, to choose this particular topic for a report at the Colloquium. So I went to the rostrum in the small auditorium 'Hörsaal II' and delivered a

  4. Diagnosis and Treatment of Symptomatic Carpal Bossing

    PubMed Central

    Radmer, Sebastian; Fresow, Robert; Tabibzada, Arash Mehdi; Kamusella, Peter; Scheer, Fabian; Andresen, Reimer

    2015-01-01

    Context Carpal bossing is an osseous formation at the dorsal portion of the quadrangular joint, which rarely becomes symptomatic. However, in some patients it causes pain, restricted mobility and can lead to complications like tendon rupture, inflammatory and degenerative joint disease. Aim In this article, we present our experiences with this rare disorder in order to improve diagnostic and therapeutic proceedings. Settings Design This is a multicenter and interdisciplinary observation made by orthopaedic surgeons and radiologists in the years 2010 to 2015. Retrospective observational study. The follow up period was 2 years. Materials and Methods In the observed time period, eight patients were diagnosed with symptomatic carpal bossing. Symptoms were pain at palmar flexion and limited mobility of the wrist in combination with a palpable protuberance over the quadrangular joint. All patients underwent X-ray, CT and MRI examinations. A conservative treatment strategy was initiated for 6 weeks in all patients, followed by a wedge resection when symptoms were persisting and disabling. Results After the conservative treatment schedule, five patients were asymptomatic. Three patients had persisting pain and were thus recommended for surgery. In the postoperative course, two patients were asymptomatic. One patient developed a type 1 complex regional pain syndrome (CRPS) in the first postoperative year, which was successfully treated with pain-adapted physiotherapy, pharmacotherapy with analgesics and calcitonin, and a triple CT-guided thoracic sympathetic nerve blockade. Conclusion Carpal bossing is a mostly asymptomatic entity, which in our experience gets symptomatic due to direct trauma or repetitive stress, especially in competitive racket sports players. It can be diagnosed by thorough clinical examination and multimodal diagnostic imaging. Conservative treatment comprises an excellent prognosis, however surgery, either wedge resection or arthrodesis, must be

  5. Dream Catchers: "Margin Call," "Boss," and Climbing the Beanstalk

    ERIC Educational Resources Information Center

    Beck, Bernard

    2012-01-01

    Two recent popular entertainments, "Margin Call" (Barnum, Dodson, Jenckes, Moosa, Quinto & Chandor, 2011) and "Boss" (Safinia, 2011), depict powerful and successful groups of bosses confronting sudden, extreme threats. They are forced to react quickly and sacrifice important values to achieve survival of their organizations. In these emergencies,…

  6. Upgrade Of The SDSS Spectrographs For BOSS

    NASA Astrophysics Data System (ADS)

    Roe, Natalie; Barkhouser, R.; Carey, L.; Carr, M.; Eisenstein, D. J.; Gunn, J. E.; Honscheid, K.; Leger, F.; Rockosi, C.; Schlegel, D. J.; Smee, S.

    2010-01-01

    A major upgrade of the Sloan Digital Sky Survey (SDSS) fiber-fed spectrographs was completed in August, 2009. The upgraded spectrographs have 50% more fibers, extended wavelength coverage and much improved throughput. Large format VPH gratings and thick, fully-depleted CCDs are special features of the upgrade, which will enable the Baryon Oscillation Spectroscopic Survey (BOSS) project to obtain spectra of 1.4M galaxies and 160,000 quasars in five years of dark time observations. We report on the details of the upgrade, including the fiber system, optics, cameras and electronics.

  7. Gender differences in the processing of standard emotional visual stimuli: integrating ERP and fMRI results

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Tian, Jie; Wang, Xiaoxiang; Hu, Jin

    2005-04-01

    The comprehensive understanding of human emotion processing needs consideration both in the spatial distribution and the temporal sequencing of neural activity. The aim of our work is to identify brain regions involved in emotional recognition as well as to follow the time sequence in the millisecond-range resolution. The effect of activation upon visual stimuli in different gender by International Affective Picture System (IAPS) has been examined. Hemodynamic and electrophysiological responses were measured in the same subjects. Both fMRI and ERP study were employed in an event-related study. fMRI have been obtained with 3.0 T Siemens Magnetom whole-body MRI scanner. 128-channel ERP data were recorded using an EGI system. ERP is sensitive to millisecond changes in mental activity, but the source localization and timing is limited by the ill-posed 'inversed' problem. We try to investigate the ERP source reconstruction problem in this study using fMRI constraint. We chose ICA as a pre-processing step of ERP source reconstruction to exclude the artifacts and provide a prior estimate of the number of dipoles. The results indicate that male and female show differences in neural mechanism during emotion visual stimuli.

  8. A Spectrograph for BigBOSS

    NASA Astrophysics Data System (ADS)

    CARTON, Pierre-Henri; Bebek, C.; Cazaux, S.; Ealet, A.; Eppelle, D.; Kneib, J.; Karst, P.; levi, M.; magneville, C.; Palanque-Delabrouille, N.; Ruhlmann-Kleider, V.; Schlegel, D.; Yeche, C.

    2012-01-01

    The Big-Boss spectrographs assembly will take in charge the light from the fiber output to the detector, including the optics, gratings, mechanics and cryostats. The 5000 fibers are split in 10 bundles of 500 ones. Each of these channel feed one spectrograph. The full bandwidth from 0.36µm to 1.05µm is split in 3 bands. Each channel is composed with one collimator (doublet lenses), a VPH grating, and a 6 lenses camera. The 500 fiber spectrum are imaged onto a 4kx4k detector thanks to the F/2 camera. Each fiber core is imaged onto 4 pixels. Each channel of the BigBOSS spectrograph will be equipped with a single-CCD camera, resulting in 30 cryostats in total for the instrument. Based on its experience of CCD cameras for projects like EROS and MegaCam, CEA/Saclay has designed small and autonomous cryogenic vessels which integrate cryo-cooling, CCD positioning and slow control interfacing capabilities. The use of a Linear Pulse Tube with its own control unit, both developed by Thales Cryogenics BV, will ensure versatility, reliability and operational flexibility. CCD's will be cooled down to 140K, with stability better than 1K. CCD's will be positioned within 15µm along the optical axis and 50µm in the XY Plan. Slow Control machines will be directly interfaced to an Ethernet network, which will allow them to be operated remotely. The concept of spectrograph leads to a very robust concept without any mechanics (except the shutters). This 30 channels has a impressive compactness with its 3m3 volume. The development of such number of channel will drive to a quasi mass production philosophy.

  9. Extreme Red Quasars in SDSS-BOSS

    NASA Astrophysics Data System (ADS)

    Hamann, Fred; Zakamska, Nadia; Paris, Isabelle; Herbst, Hanna; Villforth, Carolin; Alexandroff, Rachael; Ross, Nicholas; Greene, Jenny; Strauss, Michael

    2015-08-01

    Red quasars are believed to mark a critical transition stage of massive galaxy evolution when a blowout of gas and dust truncates the initial starburst and provides our first visible views of a luminous central AGN. Red quasars could therefore have unusual properties associated with a young evolution stage, such as higher accretion rates, higher rates of mergers and interactions, and more common or more powerful outflows capable of driving a galaxy-wide blowout (e.g., compared to normal blue quasars in presumably more evolved galaxy hosts). The recently completed Baryon Oscillation Spectroscopy Survey (BOSS) of SDSS-III has discovered many more faint quasars with higher redshifts and redder colors than any previous large survey. We combine BOSS spectra with SDSS and Wide-Field Infrared Survey Explorer (WISE) photometry of nearly 100,000 quasars to identify and characterize the red quasar population at redshifts >2. We find a number of strong trends with the amount of reddening/obscuration. For example, red quasars are 5 to 8 times more likely to have broad absorption lines and other "intrinsic" absorption lines that identify quasar-driven outflows. Perhaps most interesting is that extreme red quasars (ERQs), selected via rest-frame UV to near-IR colors similar to Dust Obscured Galaxies (DOGs), have uniquely exotic emission line properties that include extreme velocity shifts between lines and the broadest and most blueshifted [OIII] lines yet discovered (with FWHMs reaching >3000 km/s). We will discuss the implications of these results for models of the structure and evolution of quasars and their host galaxy environments.

  10. SDSS-IV eBOSS emission-line galaxy pilot survey

    NASA Astrophysics Data System (ADS)

    Comparat, J.; Delubac, T.; Jouvel, S.; Raichoor, A.; Kneib, J.-P.; Yèche, C.; Abdalla, F. B.; Le Cras, C.; Maraston, C.; Wilkinson, D. M.; Zhu, G.; Jullo, E.; Prada, F.; Schlegel, D.; Xu, Z.; Zou, H.; Bautista, J.; Bizyaev, D.; Bolton, A.; Brownstein, J. R.; Dawson, K. S.; Escoffier, S.; Gaulme, P.; Kinemuchi, K.; Malanushenko, E.; Malanushenko, V.; Mariappan, V.; Newman, J. A.; Oravetz, D.; Pan, K.; Percival, W. J.; Prakash, A.; Schneider, D. P.; Simmons, A.; Abbott, T. M. C.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Doel, P.; Eifler, T. F.; Estrada, J.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Miquel, R.; Plazas, A. A.; Reil, K.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Zhang, Y.

    2016-08-01

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195 000 emission-line galaxies (ELGs) to measure the baryonic acoustic oscillation (BAO) standard ruler at redshift 0.9. To test different ELG selection algorithms, 9000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Finally, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements. The catalog is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A121

  11. Are you a good boss--or a great one?

    PubMed

    Hill, Linda A; Lineback, Kent

    2011-01-01

    Private moments of doubt and fear come even to managers who have spent years on the job. Any number of events can trigger them: an initiative going poorly, a lukewarm performance review, a daunting new assignment. HBS professor Hill and executive Lineback have long studied the question of how manager grow and advance. Their experience brings them to a simple but troubling observation: Most bosses reach a certain level of proficiency and stay there--short of what they could and should be. Why? Because they stop working on themselves. The authors offer what they call the three imperatives for managers who seek to avoid this stagnation. First, manage yourself--who you are as a person, the beliefs and values that drive your actions, and especially how you connect with others all matter to the people you must influence. Second, manage your network. Effective managers know that they cannot avoid conflict and competition among organizational groups; they build and nurture ongoing relationships. Third, manage your team. Team members need to know what's required of them collectively and individually and what the team's values, norms, and standards are. The authors include a useful assessment tool to help readers get started. PMID:21370809

  12. Functional analysis via standardized whole-blood stimulation systems defines the boundaries of a healthy immune response to complex stimuli.

    PubMed

    Duffy, Darragh; Rouilly, Vincent; Libri, Valentina; Hasan, Milena; Beitz, Benoit; David, Mikael; Urrutia, Alejandra; Bisiaux, Aurélie; Labrie, Samuel T; Dubois, Annick; Boneca, Ivo G; Delval, Cécile; Thomas, Stéphanie; Rogge, Lars; Schmolz, Manfred; Quintana-Murci, Lluis; Albert, Matthew L

    2014-03-20

    Standardization of immunophenotyping procedures has become a high priority. We have developed a suite of whole-blood, syringe-based assay systems that can be used to reproducibly assess induced innate or adaptive immune responses. By eliminating preanalytical errors associated with immune monitoring, we have defined the protein signatures induced by (1) medically relevant bacteria, fungi, and viruses; (2) agonists specific for defined host sensors; (3) clinically employed cytokines; and (4) activators of T cell immunity. Our results provide an initial assessment of healthy donor reference values for induced cytokines and chemokines and we report the failure to release interleukin-1α as a common immunological phenotype. The observed naturally occurring variation of the immune response may help to explain differential susceptibility to disease or response to therapeutic intervention. The implementation of a general solution for assessment of functional immune responses will help support harmonization of clinical studies and data sharing.

  13. When your employee forgets who the boss is.

    PubMed

    Davidhizar, R; Giger, J N; Poole, V L

    1997-09-01

    Managers confront many types of behavior in the workplace. One interpersonal problem that presents an unusual challenge to the manager is the employee who appears to "forget who the boss is." This article addresses this unusual employee-manager problem by first describing the characteristics and dynamics of the behavior and then providing guidelines for responding to this problematic behavior.

  14. Extremely red quasars from SDSS, BOSS and WISE: classification of optical spectra

    NASA Astrophysics Data System (ADS)

    Ross, Nicholas P.; Hamann, Fred; Zakamska, Nadia L.; Richards, Gordon T.; Villforth, Carolin; Strauss, Michael A.; Greene, Jenny E.; Alexandroff, Rachael; Brandt, W. Niel; Liu, Guilin; Myers, Adam D.; Pâris, Isabelle; Schneider, Donald P.

    2015-11-01

    Quasars with extremely red infrared-to-optical colours are an interesting population that can test ideas about quasar evolution as well as orientation, obscuration and geometric effects in the so-called AGN unified model. To identify such a population, we match the quasar catalogues of the Sloan Digital Sky Survey (SDSS), the Baryon Oscillation Spectroscopic Survey (BOSS) to the Wide-Field Infrared Survey Explorer (WISE) to identify quasars with extremely high infrared-to-optical ratios. We identify 65 objects with rAB - W4Vega > 14 mag (i.e. Fν(22 μm)/Fν(r) ≳ 1000). This sample spans a redshift range of 0.28 < z < 4.36 and has a bimodal distribution, with peaks at z ˜ 0.8 and z ˜ 2.5. It includes three z > 2.6 objects that are detected in the W4 band but not W1 or W2 (i.e. `W1W2 dropouts'). The SDSS/BOSS spectra show that the majority of the objects are reddened type 1 quasars, type 2 quasars (both at low and high redshift) or objects with deep low-ionization broad absorption lines (BALs) that suppress the observed r-band flux. In addition, we identify a class of type 1 permitted broad emission-line objects at z ≃ 2-3 which are characterized by emission line rest-frame equivalent widths (REWs) of ≳150 Å, much larger than those of typical quasars. In particular, 55 per cent (45 per cent) of the non-BAL type 1s with measurable C IV in our sample have REW(C IV) > 100 (150) Å, compared to only 5.8 per cent (1.3 per cent) for non-BAL quasars in BOSS. These objects often also have unusual line ratios, such as very high N V/Ly α ratios. These large REWs might be caused by suppressed continuum emission analogous to type 2 quasars; however, there is no obvious mechanism in standard unified models to suppress the continuum without also obscuring the broad emission lines.

  15. 77 FR 3500 - Hugo Boss Cleveland, Inc., Including Workers Whose Unemployment Insurance (UI) Wages Are Paid...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-24

    ... Cleveland, Inc., Brooklyn, Ohio. The notice was published in the Federal Register on May 5, 2010 (75 FR... Employment and Training Administration Hugo Boss Cleveland, Inc., Including Workers Whose Unemployment... location of Hugo Boss Cleveland, Inc. had their wages reported under a separate unemployment insurance...

  16. Differential Effects of Tissue-Specific Deletion of BOSS on Feeding Behaviors and Energy Metabolism

    PubMed Central

    Kohyama-Koganeya, Ayako; Kurosawa, Mizuki; Hirabayashi, Yoshio

    2015-01-01

    Food intake and energy metabolism are tightly controlled to maintain stable energy homeostasis and healthy states. Thus, animals detect their stored energy levels, and based on this, they determine appropriate food intake and meal size. Drosophila melanogaster putative G protein-coupled receptor, Bride of sevenless (BOSS) is a highly evolutionarily conserved protein that responds to extracellular glucose levels in order to regulate energy homeostasis. To address how BOSS regulates energy homeostasis, we characterized a boss mutant by assessing its food intake and stored energy levels. Boss mutants exhibited increased food intake but decreased stored triacylglyceride levels. Using boss-GAL4 drivers, we found that boss is expressed in select tissues that are involved in nutrient sensing and food intake, in a subset of neurons in brain and chemosensory organs, in fat body, and in endocrine cells in gut (enteroendocrine cells). Flies with tissue-specific boss knockdowns in these tissues had abnormal stored energy levels and abnormal food intake. These results suggest that BOSS in either neurons or peripheral nutrient-sensing tissues affects energy homeostasis in ways that relate to the sensing of nutrients and regulation of food intake. PMID:26193363

  17. Spectroscopic identification of type 2 quasars at z < 1 in SDSS-III/BOSS

    NASA Astrophysics Data System (ADS)

    Yuan, Sihan; Strauss, Michael A.; Zakamska, Nadia L.

    2016-10-01

    The physics and demographics of type 2 quasars remain poorly understood, and new samples of such objects selected in a variety of ways can give insight into their physical properties, evolution, and relationship to their host galaxies. We present a sample of 2758 type 2 quasars at z ≲ 1 from the Sloan Digital Sky Survey-III (SDSS-III)/Baryon Oscillation Spectroscopic Survey (BOSS) spectroscopic data base, selected on the basis of their emission-line properties. We probe the luminous end of the population by requiring the rest-frame equivalent width of [O III] to be >100 Å. We distinguish our objects from star-forming galaxies and type 1 quasars using line widths, standard emission line ratio diagnostic diagrams at z < 0.52 and detection of [Ne V]λ3426 Å at z > 0.52. The majority of our objects have [O III] luminosities in the range 1.2 × 1042-3.8 × 1043 erg s-1 and redshifts between 0.4 and 0.65. Our sample includes over 400 type 2 quasars with incorrectly measured redshifts in the BOSS data base; such objects often show kinematic substructure or outflows in the [O III] line. The majority of the sample has counterparts in the Wide-field Infrared Survey Explorer survey, with median infrared luminosity νLν[12 μm] = 4.2 × 1044 erg s- 1. Only 34 per cent of the newly identified type 2 quasars would be selected by infrared colour cuts designed to identify obscured active nuclei, highlighting the difficulty of identifying complete samples of type 2 quasars. We make public the multi-Gaussian decompositions of all [O III] profiles for the new sample and for 568 type 2 quasars from SDSS I/II, together with non-parametric measures of the [O III] line profile shapes. We also identify over 600 candidate double-peaked [O III] profiles.

  18. Skin surface lipids of the domestic chicken, and neutral lipid standards as stimuli for the penetration response of Austrobilharzia variglandis cercariae.

    PubMed

    Zibulewsky, J; Fried, B; Bacha, W J

    1982-10-01

    Lipids were extracted from the skin of 2-wk-old domestic chickens using sterile cotton gauze dampened with chloroform:methanol (2:1). Preparative thin-layer chromatography separated the skin lipids into six major fractions: phospholipids, free sterols, free fatty acids, triglycerides, methyl esters, sterol esters. The penetration response of the marine avian schistosome cercaria, Austrobilharzia variglandis, to chicken skin lipid fractions, and to neutral lipid standards, was tested by coating lipids on agar in a Petri dish containing a seawater overlay. All neutral lipids tested produced significantly greater penetration responses than the chloroform control. The phospholipid skin fraction killed cercariae. Lipid from whole chicken skin produced the greatest penetration response, followed by free fatty acids and free sterol skin fractions. Of the standards tested, the whole neutral lipid standard, containing cholesterol, oleic acid, triolein, methyl oleate, and cholesteryl oleate, produced the greatest response, followed by the cholesterol standard and the oleic acid standard. PMID:7131196

  19. Initial clinical experience of CrossBoss catheter for in-stent chronic total occlusion lesions

    PubMed Central

    Zhao, Lei; Li, Long-Bo; Wang, Zhi-Hui; Shi, Yong-Feng; Wu, Jun-Duo; Zhang, Ji-Chang; Liu, Bin

    2016-01-01

    Abstract Background: The CrossBoss coronary chronic total occlusion (CTO) crossing catheter has been demonstrated to have greatly improved the success rate of crossing CTO lesions, but there are no published data on its application for in-stent CTO lesions. Methods: In the current study, we retrospectively reviewed the clinical data of 8 patients with in-stent CTO lesions that were managed with the CrossBoss catheter and herein we report the efficacy and safety of the CrossBoss crossing and re-entry system for this clinically challenging condition. Results: The CrossBoss catheter was used for 8 patients with in-stent CTO lesions, which resulted in success in 6 cases and failure in 2 cases, with a 75% success rate. Of the 6 patients with successful treatment, 5 cases had the occlusive lesions crossed with the CrossBoss catheter through a proximal lumen-to-distal lumen approach, whereas the remaining case had his occlusive lesions penetrated by the CrossBoss catheter and the guidewire. Two cases failed in treatment as the CrossBoss catheter could not cross the occlusive lesions. The 6 cases with successful treatment included 3 cases with occlusive lesions in the left anterior descending artery, 1 case with occlusive lesions in the obtuse marginal branches, and 2 cases with occlusive lesions in the right coronary artery, and the 2 cases with failure in treatment had their occlusive lesions in the right coronary artery. In addition, patients with a higher Japan chronic total occlusion score were found to have a lower success rate of crossing the occlusive lesions. None of the patients developed complications. Conclusion: Our study demonstrates that the CrossBoss catheter has a high success rate and is safe for in-stent CTOs and can be recommended for this rather clinically challenging condition. PMID:27749568

  20. Effective Stimuli for Constructing Reliable Neuron Models

    PubMed Central

    Druckmann, Shaul; Berger, Thomas K.; Schürmann, Felix; Hill, Sean; Markram, Henry; Segev, Idan

    2011-01-01

    The rich dynamical nature of neurons poses major conceptual and technical challenges for unraveling their nonlinear membrane properties. Traditionally, various current waveforms have been injected at the soma to probe neuron dynamics, but the rationale for selecting specific stimuli has never been rigorously justified. The present experimental and theoretical study proposes a novel framework, inspired by learning theory, for objectively selecting the stimuli that best unravel the neuron's dynamics. The efficacy of stimuli is assessed in terms of their ability to constrain the parameter space of biophysically detailed conductance-based models that faithfully replicate the neuron's dynamics as attested by their ability to generalize well to the neuron's response to novel experimental stimuli. We used this framework to evaluate a variety of stimuli in different types of cortical neurons, ages and animals. Despite their simplicity, a set of stimuli consisting of step and ramp current pulses outperforms synaptic-like noisy stimuli in revealing the dynamics of these neurons. The general framework that we propose paves a new way for defining, evaluating and standardizing effective electrical probing of neurons and will thus lay the foundation for a much deeper understanding of the electrical nature of these highly sophisticated and non-linear devices and of the neuronal networks that they compose. PMID:21876663

  1. Cranial Bosses of Choerosaurus dejageri (Therapsida, Therocephalia): Earliest Evidence of Cranial Display Structures in Eutheriodonts

    PubMed Central

    Benoit, Julien; Manger, Paul R.; Fernandez, Vincent; Rubidge, Bruce S.

    2016-01-01

    Choerosaurus dejageri, a non-mammalian eutheriodont therapsid from the South African late Permian (~259 Ma), has conspicuous hemispheric cranial bosses on the maxilla and the mandible. These bosses, the earliest of this nature in a eutheriodont, potentially make C. dejageri a key species for understanding the evolutionary origins of sexually selective behaviours (intraspecific competition, ritualized sexual and intimidation displays) associated with cranial outgrowths at the root of the clade that eventually led to extant mammals. Comparison with the tapinocephalid dinocephalian Moschops capensis, a therapsid in which head butting is strongly supported, shows that the delicate structure of the cranial bosses and the gracile structure of the skull of Choerosaurus would be more suitable for display and low energy combat than vigorous head butting. Thus, despite the fact that Choerosaurus is represented by only one skull (which makes it impossible to address the question of sexual dimorphism), its cranial bosses are better interpreted as structures involved in intraspecific selection, i.e. low-energy fighting or display. Display structures, such as enlarged canines and cranial bosses, are widespread among basal therapsid clades and are also present in the putative basal therapsid Tetraceratops insignis. This suggests that sexual selection may have played a more important role in the distant origin and evolution of mammals earlier than previously thought. Sexual selection may explain the subsequent independent evolution of cranial outgrowths and pachyostosis in different therapsid lineages (Biarmosuchia, Dinocephalia, Gorgonopsia and Dicynodontia). PMID:27548428

  2. Cranial Bosses of Choerosaurus dejageri (Therapsida, Therocephalia): Earliest Evidence of Cranial Display Structures in Eutheriodonts.

    PubMed

    Benoit, Julien; Manger, Paul R; Fernandez, Vincent; Rubidge, Bruce S

    2016-01-01

    Choerosaurus dejageri, a non-mammalian eutheriodont therapsid from the South African late Permian (~259 Ma), has conspicuous hemispheric cranial bosses on the maxilla and the mandible. These bosses, the earliest of this nature in a eutheriodont, potentially make C. dejageri a key species for understanding the evolutionary origins of sexually selective behaviours (intraspecific competition, ritualized sexual and intimidation displays) associated with cranial outgrowths at the root of the clade that eventually led to extant mammals. Comparison with the tapinocephalid dinocephalian Moschops capensis, a therapsid in which head butting is strongly supported, shows that the delicate structure of the cranial bosses and the gracile structure of the skull of Choerosaurus would be more suitable for display and low energy combat than vigorous head butting. Thus, despite the fact that Choerosaurus is represented by only one skull (which makes it impossible to address the question of sexual dimorphism), its cranial bosses are better interpreted as structures involved in intraspecific selection, i.e. low-energy fighting or display. Display structures, such as enlarged canines and cranial bosses, are widespread among basal therapsid clades and are also present in the putative basal therapsid Tetraceratops insignis. This suggests that sexual selection may have played a more important role in the distant origin and evolution of mammals earlier than previously thought. Sexual selection may explain the subsequent independent evolution of cranial outgrowths and pachyostosis in different therapsid lineages (Biarmosuchia, Dinocephalia, Gorgonopsia and Dicynodontia). PMID:27548428

  3. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling the clustering and halo occupation distribution of BOSS CMASS galaxies in the Final Data Release

    NASA Astrophysics Data System (ADS)

    Rodríguez-Torres, Sergio A.; Chuang, Chia-Hsun; Prada, Francisco; Guo, Hong; Klypin, Anatoly; Behroozi, Peter; Hahn, Chang Hoon; Comparat, Johan; Yepes, Gustavo; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Maraston, Claudia; McBride, Cameron K.; Tinker, Jeremy; Gottlöber, Stefan; Favole, Ginevra; Shu, Yiping; Kitaura, Francisco-Shu; Bolton, Adam; Scoccimarro, Román; Samushia, Lado; Schlegel, David; Schneider, Donald P.; Thomas, Daniel

    2016-08-01

    We present a study of the clustering and halo occupation distribution of Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies in the redshift range 0.43 < z < 0.7 drawn from the Final SDSS-III Data Release. We compare the BOSS results with the predictions of a halo abundance matching (HAM) clustering model that assigns galaxies to dark matter haloes selected from the large BigMultiDark N-body simulation of a flat Λ cold dark matter Planck cosmology. We compare the observational data with the simulated ones on a light cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fibre collisions are included in the model, which reproduces within 1σ errors the observed monopole of the two-point correlation function at all relevant scales: from the smallest scales, 0.5 h-1 Mpc, up to scales beyond the baryon acoustic oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to k ˜ 1 h Mpc-1), and the three-point correlation function. The quadrupole of the correlation function presents some tensions with observations. We discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. We compare the stellar-to-halo mass relation for the CMASS sample measured using weak lensing in the Canada-France-Hawaii Telescope Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1σ. The BigMD-BOSS light cone including properties of BOSS galaxies and halo properties is made publicly available.

  4. Intrinsic alignments of SDSS-III BOSS LOWZ sample galaxies

    NASA Astrophysics Data System (ADS)

    Singh, Sukhdeep; Mandelbaum, Rachel; More, Surhud

    2015-06-01

    Intrinsic alignments (IA) of galaxies, i.e. correlations of galaxy shapes with each other (II) or with the density field (gI), are potentially a major astrophysical source of contamination for weak lensing surveys. We present the results of IA measurements of galaxies on 0.1-200 h-1 Mpc scales using the SDSS-III BOSS low-redshift (LOWZ) sample, in the redshift range 0.16 < z < 0.36. We extend the existing IA measurements for spectroscopic luminous red galaxies (LRGs) to lower luminosities, and show that the luminosity dependence of large-scale IA can be well described by a power law. Within the limited redshift and colour range of our sample, we observe no significant redshift or colour dependence of IA. We measure the halo mass of galaxies using galaxy-galaxy lensing, and show that the mass dependence of large-scale IA is also well described by a power law. We detect variations in the scale dependence of IA with mass and luminosity, which underscores the need to use flexible templates in order to remove the IA signal. We also study the environment dependence of IA by splitting the sample into field and group galaxies, which are further split into satellite and central galaxies. We show that group central galaxies are aligned with their haloes at small scales and also are aligned with the tidal fields out to large scales. We also detect the radial alignments of satellite galaxies within groups. These results can be used to construct better IA models for removal of this contaminant to the weak lensing signal.

  5. 49 CFR 571.108 - Standard No. 108; Lamps, reflective devices, and associated equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., mounting hole bosses, reflex reflector area, beads or rims that may glow or produce small areas of... on the lens face and the black area surrounding the signal lamp recommended in SAE Standard...

  6. 49 CFR 571.108 - Standard No. 108; Lamps, reflective devices, and associated equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... pattern, and does not include transparent lenses, mounting hole bosses, reflex reflector area, beads or... on the lens face and the black area surrounding the signal lamp recommended in SAE Standard...

  7. Meet the New Boss…Same as the Old Boss? Female Supervisors and Subordinate Career Prospects*

    PubMed Central

    Maume, David J.

    2010-01-01

    Whereas prior research has focused on women’s access to managerial authority, an equally important question is the effect on subordinates’ careers when they report to a female boss. One line of thought suggests that female bosses act as change agents by fostering the careers of female subordinates, whereas the cog in the machine perspective suggests that female bosses either willingly or are constrained to promote men’s careers. Using data from the 2002 National Study of the Changing Workforce, analytic models of subordinates’ perceived job-related support from supervisors and advancement prospects were developed. Results were consistent with the cog in the machine perspective in that in contrast to women, men received more job-related support and were more optimistic about their careers when they reported to a female supervisor. Yet, given the paucity of research on this topic, more research (especially longitudinal studies) is needed to fully understand how supervisors affect subordinates’ careers. PMID:21180397

  8. VizieR Online Data Catalog: E-BOSS. II. Catalogue second release (Peri+, 2015)

    NASA Astrophysics Data System (ADS)

    Peri, C. S.; Benaglia, P.; Isequilla, N. L.

    2015-07-01

    E-BOSS first release (r1, Peri et al., 2012A&A...538A.108P) was based on two samples. Group 1 consisted of a set of sources taken from Noriega-Crespo et al. (1997AJ....113..780N) and Group 2 was a list extracted from Tetzlaff et al. (2011MNRAS.410..190T, Cat. J/MNRAS/410/190). To build the present and second E-BOSS release (r2) we used samples extended to other spectral types, sources with no public WISE data at the moment of making E-BOSS r1, bow shocks from the literature, and bow shocks found serendipitously. (5 data files).

  9. The XMM Cluster Survey: The Halo Occupation Number of BOSS galaxies in X-ray clusters

    NASA Astrophysics Data System (ADS)

    Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

    2016-08-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark-matter halos of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 - 15. Our directly-measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. (2013) for the BOSS LOWZ sample and White et al. (2011) for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fit alpha-index of 0.91±0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. (2011) and Parejko et al. (2013). In summary, our study provides independent support for the HOD-models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

  10. Disabling hand injuries in boxing: boxer's knuckle and traumatic carpal boss.

    PubMed

    Melone, Charles P; Polatsch, Daniel B; Beldner, Steven

    2009-10-01

    This article describes the treatment of the two most debilitating hand-related boxing injuries: boxer's knuckle and traumatic carpal boss. Recognition of the normal anatomy as well as the predictable pathology facilitates an accurate diagnosis and precision surgery. For boxer's knuckle, direct repair of the disrupted extensor hood, without the need for tendon augmentation, has been consistently employed; for traumatic carpal boss, arthrodesis of the destabilized carpometacarpal joints has been the preferred method of treatment. Precisely executed operative treatment of both injuries has resulted in a favorable outcome, as in the vast majority of cases the boxers have experienced relief of pain, restoration of function, and an unrestricted return to competition.

  11. The large-scale quasar-Lyman α forest cross-correlation from BOSS

    SciTech Connect

    Font-Ribera, Andreu; Arnau, Eduard; Miralda-Escudé, Jordi E-mail: edu.arnau.lazaro@gmail.com; and others

    2013-05-01

    We measure the large-scale cross-correlation of quasars with the Lyα forest absorption in redshift space, using ∼ 60000 quasar spectra from Data Release 9 (DR9) of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is detected over a wide range of scales, up to comoving separations r of 80 h{sup −1}Mpc. For r > 15 h{sup −1}Mpc, we show that the cross-correlation is well fitted by the linear theory prediction for the mean overdensity around a quasar host halo in the standard ΛCDM model, with the redshift distortions indicative of gravitational evolution detected at high confidence. Using previous determinations of the Lyα forest bias factor obtained from the Lyα autocorrelation, we infer the quasar bias factor to be b{sub q} = 3.64{sup +0.13}{sub −0.15} at a mean redshift z = 2.38, in agreement with previous measurements from the quasar auto-correlation. We also obtain a new estimate of the Lyα forest redshift distortion factor, β{sub F} = 1.1±0.15, slightly larger than but consistent with the previous measurement from the Lyα forest autocorrelation. The simple linear model we use fails at separations r < 15h{sup −1}Mpc, and we show that this may reasonably be due to the enhanced ionization due to radiation from the quasars. We also provide the expected correction that the mass overdensity around the quasar implies for measurements of the ionizing radiation background from the line-of-sight proximity effect.

  12. A "WISE BOSS": Finding The Cosmic Monsters in the Mid-Infrared Lochs

    NASA Astrophysics Data System (ADS)

    Ross, Nicholas; Hamann, F. W.; Alexandroff, R.; Brandt, W. N.; Strauss, M. A.; Dey, A.; Richards, G. T.; Worseck, G.; Zakamska, N. L.; Eisenstein, D.; Ge, J.; Glikman, E.; Greene, J. E.; Haggard, D.; Krolik, J. H.; Myers, A. D.; Petitjean, P.; Streblyanska, A.; Schawinski, K.; Shen, Y.; Villforth, C.; McMahon, R.

    2013-01-01

    Mid-infrared photometry of QSOs provide an important constraint on the presence of hot dust in the vicinity of the active nucleus. However, assembling large statistical MIR samples of quasars at the height of the ``quasar epoch'' ( 2.5) has, up until now, been challenging due to either wide but relatively shallow optical quasar surveys, or deep but narrow mid-IR data. The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) is the state-of-the-art in optical wide-field spectroscopy, and has over 150,000 quasars confirmed, with the majority of the quasar data at z=2.2-3.5. We combine these data with the all-sky mid-infrared coverage from the Wide-Field Infrared Survey Explorer (WISE), and initially concentrate on BOSS quasars with ``extreme'' colors, e.g. r-[22]>14, and those detected only in the redder WISE bands, a.k.a. "the W1W2drops". We find that these selections identify a heterogeneous sample within the BOSS quasar data, but also provide a key tool for finding interesting populations including the 2.5 Type II QSO population. We relate these very red BOSS quasars to the recent discoveries of the ``hyper-LIRG" and ``Hot Dust Obscured Galaxy'' (or Hot DOG) population.

  13. Accommodation for flickering stimuli.

    PubMed

    Owens, D A; Wolfe, J M

    1985-01-01

    A laser optometer was used to measure accommodative responses of three observers for sinusoidal gratings presented in Maxwellian view at optical distances ranging from 0 to 4 diopters. Contrast of the stimuli was modulated spatially at 1.0, 4.2 and 6.5 cycles deg.-1 (cpd), and temporally at six frequencies ranging from 3.0 to 40 Hz. Accommodation was consistently more accurate for the 4.2 cpd than for either the 1.0 or 6.5 cpd gratings. Furthermore, accommodative responsiveness for the 4.2 cpd was not affected by temporal modulation, while that for the other spatial frequencies improved monotonically as a function of temporal frequency. These results reinforce earlier reports that accommodation is most responsive for contrast of intermediate spatial frequencies and they indicate that stimulus flicker generally degrades accommodation for spatial contrast.

  14. Measurement of baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

    SciTech Connect

    Slosar, Anže; Iršič, Vid; Kirkby, David; Blomqvist, Michael; Bailey, Stephen; Carithers, Bill; Busca, Nicolás G.; Aubourg, Éric; Bautista, Julian E.; Bhardwaj, Vaishali; Bolton, Adam S.; Brownstein, Joel; Dawson, Kyle S.; Bovy, Jo; Croft, Rupert A.C.; Ho, Shirley; Font-Ribera, Andreu; and others

    2013-04-01

    We use the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) to detect and measure the position of the Baryonic Acoustic Oscillation (BAO) feature in the three-dimensional correlation function in the Lyman-α flux fluctuations at a redshift z{sub eff} = 2.4. The feature is clearly detected at significance between 3 and 5 sigma (depending on the broadband model and method of error covariance matrix estimation) and is consistent with predictions of the standard ΛCDM model. We assess the biases in our method, stability of the error covariance matrix and possible systematic effects. We fit the resulting correlation function with several models that decouple the broadband and acoustic scale information. For an isotropic dilation factor, we measure 100 × (α{sub iso} − 1) = −1.6{sup +2.0+4.3+7.4}{sub −2.0−4.1−6.8} (stat.) ±1.0 (syst.) (multiple statistical errors denote 1,2 and 3 sigma confidence limits) with respect to the acoustic scale in the fiducial cosmological model (flat ΛCDM with Ω{sub m} = 0.27, h = 0.7). When fitting separately for the radial and transversal dilation factors we find marginalised constraints 100 × (α{sub ||} − 1) = −1.3{sup +3.5+7.6+12.3}{sub −3.3−6.7−10.2} (stat.) ±2.0 (syst.) and 100 × (α{sub p}erpendicular − 1) = −2.2{sup +7.4+17}{sub −7.1−15} (stat.) ±3.0 (syst.). The dilation factor measurements are significantly correlated with cross-correlation coefficient of ∼ −0.55. Errors become significantly non-Gaussian for deviations over 3 standard deviations from best fit value. Because of the data cuts and analysis method, these measurements give tighter constraints than a previous BAO analysis of the BOSS DR9 Lyman-α sample, providing an important consistency test of the standard cosmological model in a new redshift regime.

  15. Who's Afraid of the Boss: Cultural Differences in Social Hierarchies Modulate Self-Face Recognition in Chinese and Americans

    PubMed Central

    Liew, Sook-Lei; Ma, Yina; Han, Shihui; Aziz-Zadeh, Lisa

    2011-01-01

    Human adults typically respond faster to their own face than to the faces of others. However, in Chinese participants, this self-face advantage is lost in the presence of one's supervisor, and they respond faster to their supervisor's face than to their own. While this “boss effect” suggests a strong modulation of self-processing in the presence of influential social superiors, the current study examined whether this effect was true across cultures. Given the wealth of literature on cultural differences between collectivist, interdependent versus individualistic, independent self-construals, we hypothesized that the boss effect might be weaker in independent than interdependent cultures. Twenty European American college students were asked to identify orientations of their own face or their supervisors' face. We found that European Americans, unlike Chinese participants, did not show a “boss effect” and maintained the self-face advantage even in the presence of their supervisor's face. Interestingly, however, their self-face advantage decreased as their ratings of their boss's perceived social status increased, suggesting that self-processing in Americans is influenced more by one's social status than by one's hierarchical position as a social superior. In addition, when their boss's face was presented with a labmate's face, American participants responded faster to the boss's face, indicating that the boss may represent general social dominance rather than a direct negative threat to oneself, in more independent cultures. Altogether, these results demonstrate a strong cultural modulation of self-processing in social contexts and suggest that the very concept of social positions, such as a boss, may hold markedly different meanings to the self across Western and East Asian cultures. PMID:21359209

  16. Who's afraid of the boss: cultural differences in social hierarchies modulate self-face recognition in Chinese and Americans.

    PubMed

    Liew, Sook-Lei; Ma, Yina; Han, Shihui; Aziz-Zadeh, Lisa

    2011-01-01

    Human adults typically respond faster to their own face than to the faces of others. However, in Chinese participants, this self-face advantage is lost in the presence of one's supervisor, and they respond faster to their supervisor's face than to their own. While this "boss effect" suggests a strong modulation of self-processing in the presence of influential social superiors, the current study examined whether this effect was true across cultures. Given the wealth of literature on cultural differences between collectivist, interdependent versus individualistic, independent self-construals, we hypothesized that the boss effect might be weaker in independent than interdependent cultures. Twenty European American college students were asked to identify orientations of their own face or their supervisors' face. We found that European Americans, unlike Chinese participants, did not show a "boss effect" and maintained the self-face advantage even in the presence of their supervisor's face. Interestingly, however, their self-face advantage decreased as their ratings of their boss's perceived social status increased, suggesting that self-processing in Americans is influenced more by one's social status than by one's hierarchical position as a social superior. In addition, when their boss's face was presented with a labmate's face, American participants responded faster to the boss's face, indicating that the boss may represent general social dominance rather than a direct negative threat to oneself, in more independent cultures. Altogether, these results demonstrate a strong cultural modulation of self-processing in social contexts and suggest that the very concept of social positions, such as a boss, may hold markedly different meanings to the self across Western and East Asian cultures.

  17. The SDSS-III BOSS quasar lens survey: discovery of 13 gravitationally lensed quasars

    NASA Astrophysics Data System (ADS)

    More, Anupreeta; Oguri, Masamune; Kayo, Issha; Zinn, Joel; Strauss, Michael A.; Santiago, Basilio X.; Mosquera, Ana M.; Inada, Naohisa; Kochanek, Christopher S.; Rusu, Cristian E.; Brownstein, Joel R.; da Costa, Luiz N.; Kneib, Jean-Paul; Maia, Marcio A. G.; Quimby, Robert M.; Schneider, Donald P.; Streblyanska, Alina; York, Donald G.

    2016-02-01

    We report the discovery of 13 confirmed two-image quasar lenses from a systematic search for gravitationally lensed quasars in the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). We adopted a methodology similar to that used in the SDSS Quasar Lens Search (SQLS). In addition to the confirmed lenses, we report 11 quasar pairs with small angular separations ( ≲ 2 arcsec) confirmed from our spectroscopy, which are either projected pairs, physical binaries, or possibly quasar lens systems whose lens galaxies have not yet been detected. The newly discovered quasar lens system, SDSS J1452+4224 at zs ≈ 4.8 is one of the highest redshift multiply imaged quasars found to date. Furthermore, we have over 50 good lens candidates yet to be followed up. Owing to the heterogeneous selection of BOSS quasars, the lens sample presented here does not have a well-defined selection function.

  18. VizieR Online Data Catalog: SDSS/BOSS/TDSS CIV BAL quasars (Grier+, 2016)

    NASA Astrophysics Data System (ADS)

    Grier, C. J.; Brandt, W. N.; Hall, P. B.; Trump, J. R.; Filiz, Ak N.; Anderson, S. F.; Green, P. J.; Schneider, D. P.; Sun, M.; Vivek, M.; Beatty, T. G.; Brownstein, J. R.; Roman-Lopes, A.

    2016-08-01

    We began with the 2005 targets from the BAL catalog of Gibson et al. (2009, J/ApJ/692/758), which were observed by SDSS and targeted for additional observations with Baryon Oscillation Spectroscopic Survey (BOSS; Eisenstein et al. 2011AJ....142...72E; Dawson et al. 2013AJ....145...10D) and Time Domain Spectroscopic Survey (TDSS; Morganson et al. 2015ApJ...806..244M). We then searched for BOSS and TDSS observations of these targets as of 2015 June 30, identifying 172 targets that were observed by all three surveys. We restricted the redshift range of our sample to 1.5

  19. The MICRO-BOSS scheduling system: Current status and future efforts

    NASA Technical Reports Server (NTRS)

    Sadeh, Norman M.

    1993-01-01

    In this paper, a micro-opportunistic approach to factory scheduling was described that closely monitors the evolution of bottlenecks during the construction of the schedule, and continuously redirects search towards the bottleneck that appears to be most critical. This approach differs from earlier opportunistic approaches, as it does not require scheduling large resource subproblems or large job subproblems before revising the current scheduling strategy. This micro-opportunistic approach was implemented in the context of the MICRO-BOSS factory scheduling system. A study comparing MICRO-BOSS against a macro-opportunistic scheduler suggests that the additional flexibility of the micro-opportunistic approach to scheduling generally yields important reductions in both tardiness and inventory.

  20. Plasma Sprayed Bondable Stainless Surface (BOSS) Coatings for Corrosion Protection and Adhesion Treatments

    NASA Technical Reports Server (NTRS)

    Davis, G. D.; Groff, G. B.; Rooney, M.; Cooke, A. V.; Boothe, R.

    1995-01-01

    Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.

  1. Comparing modelling techniques when designing VPH gratings for BigBOSS

    NASA Astrophysics Data System (ADS)

    Poppett, Claire; Edelstein, Jerry; Lampton, Michael; Jelinsky, Patrick; Arns, James

    2012-09-01

    BigBOSS is a Stage IV Dark Energy instrument based on the Baryon Acoustic Oscillations (BAO) and Red Shift Distortions (RSD) techniques using spectroscopic data of 20 million ELG and LRG galaxies at 0.5<=z<=1.6 in addition to several hundred thousand QSOs at 0.5<=z<=3.5. When designing BigBOSS instrumentation, it is imperative to maximize throughput whilst maintaining a resolving power of between R=1500 and 4000 over a wavelength range of 360-980 nm. Volume phase Holographic (VPH) gratings have been identified as a key technology which will enable the efficiency requirement to be met, however it is important to be able to accurately predict their performance. In this paper we quantitatively compare different modelling techniques in order to assess the parameter space over which they are more capable of accurately predicting measured performance. Finally we present baseline parameters for grating designs that are most suitable for the BigBOSS instrument.

  2. The MICRO-BOSS scheduling system: Current status and future efforts

    NASA Technical Reports Server (NTRS)

    Sadeh, Norman M.

    1992-01-01

    In this paper, a micro-opportunistic approach to factory scheduling was described that closely monitors the evolution of bottlenecks during the construction of the schedule and continuously redirects search towards the bottleneck that appears to be most critical. This approach differs from earlier opportunistic approaches, as it does not require scheduling large resource subproblems or large job subproblems before revising the current scheduling strategy. This micro-opportunistic approach was implemented in the context of the MICRO-BOSS factory scheduling system. A study comparing MICRO-BOSS against a macro-opportunistic scheduler suggests that the additional flexibility of the micro-opportunistic approach to scheduling generally yields important reductions in both tardiness and inventory. Current research efforts include: adaptation of MICRO-BOSS to deal with sequence-dependent setups and development of micro-opportunistic reactive scheduling techniques that will enable the system to patch the schedule in the presence of contingencies such as machine breakdowns, raw materials arriving late, job cancellations, etc.

  3. [Stimuli-sensitive polymer systems].

    PubMed

    Le Cerf, D

    2014-11-01

    The polymers can be found in different forms in solution (particles, capsules, pseudo-micelles, hydrogels…) or on surface with important prospects in many field applications. These polymer systems are particularly very good candidates to entrap, transport and deliver an active substance in biomedical applications however with many limitations on control of release of a given target. The stimuli-sensitive polymers, also called smart or environmentally sensitive polymers, present physical or chemical changes under the action of small variations of an external stimulus. This signal acts as a stimulus which causes the change of conformation and/or solvation of the macromolecular chains by modifying their various interactions. The stimuli are classified into two broad categories: physical or external stimuli: temperature, mechanical stress, light, magnetic and electric fields; chemical and biochemical or internal stimuli: pH, ionic strength, chemical molecule (glucose, redox) or biochemical (enzymes, antigens…). The use of stimuli-sensitive pathway is widely used in the literature to enhance or trigger the release of an active compound. In this paper, we present the different stimuli addressing the theoretical aspects, polymers corresponding to these stimuli. Some examples illustrate these systems for the controlled release of active compounds.

  4. Headphone localization of speech stimuli

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Wenzel, Elizabeth M.

    1991-01-01

    Recently, three dimensional acoustic display systems have been developed that synthesize virtual sound sources over headphones based on filtering by Head-Related Transfer Functions (HRTFs), the direction-dependent spectral changes caused primarily by the outer ears. Here, 11 inexperienced subjects judged the apparent spatial location of headphone-presented speech stimuli filtered with non-individualized HRTFs. About half of the subjects 'pulled' their judgements toward either the median or the lateral-vertical planes, and estimates were almost always elevated. Individual differences were pronounced for the distance judgements; 15 to 46 percent of stimuli were heard inside the head with the shortest estimates near the median plane. The results infer that most listeners can obtain useful azimuth information from speech stimuli filtered by nonindividualized RTFs. Measurements of localization error and reversal rates are comparable with a previous study that used broadband noise stimuli.

  5. Crowding of biological motion stimuli.

    PubMed

    Ikeda, Hanako; Watanabe, Katsumi; Cavanagh, Patrick

    2013-01-01

    It is difficult to identify a target in the peripheral visual field when it is flanked by distractors. In the present study, we investigated this "crowding" effect for biological motion stimuli. Three walking biological motion stimuli were presented horizontally in the periphery with various distances between them, and observers reported the walking direction of the central figure. When the inter-walker distance was small, discriminating the direction became difficult. Moreover, the reported direction for the central target was not simply noisier, but reflected a degree of pooling of the three directions from the target and two flankers. However, when the two flanking distractors were scrambled walking biological motion stimuli, crowding was not seen. This result suggests that the crowding of biological motion stimuli occurs at a high-level of motion perception.

  6. Cluster Lensing Profiles Derived from a Redshift Enhancement of Magnified BOSS-survey Galaxies

    NASA Astrophysics Data System (ADS)

    Coupon, Jean; Broadhurst, Tom; Umetsu, Keiichi

    2013-07-01

    We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M 200 ~ 1.4-1.8 × 1014 M ⊙ for the optically detected cluster samples, and M 200 ~ 5.0 × 1014 M ⊙ for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.

  7. CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES

    SciTech Connect

    Coupon, Jean; Umetsu, Keiichi; Broadhurst, Tom

    2013-07-20

    We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M{sub 200} {approx} 1.4-1.8 Multiplication-Sign 10{sup 14} M{sub Sun} for the optically detected cluster samples, and M{sub 200} {approx} 5.0 Multiplication-Sign 10{sup 14} M{sub Sun} for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.

  8. Estimating the angular power spectrum of z > 2 BOSS QSOs using the MASTER method

    NASA Astrophysics Data System (ADS)

    Maldonado, Felipe; Huffenberger, Kevin; Rotti, Aditya

    2016-01-01

    We implement the MASTER method for angular power spectrum estimation and apply it to z > 2 quasars selected by the SDSS-III BOSS survey. Quasars are filtered for completeness and bad spectra, and include ~100,000 QSOs in the CORE sample and ~75,000 in the non-uniform BONUS sample. We estimate the angular power spectrum in redshift shells to constrain the matter power spectrum and quasar properties. In the future, we will jointly analyze overlapping Cosmic Microwave Background lensing maps from the Atacama Cosmology Telescope to place further constraints.

  9. How do people order stimuli?

    PubMed

    Kemp, Simon; Grace, Randolph C

    2014-08-01

    People may find it easier to construct an order after first representing stimuli on a scale or categorizing them, particularly when the number of stimuli to be ordered is large or when some of them must be remembered. Five experiments tested this hypothesis. In two of these experiments (1 and 3), we asked participants to rank line lengths or to rank photographs by artistic value. The participants provided evidence of how they performed these tasks, and this evidence indicated that they often made use of some preliminary representation--either a metric or a categorization. Two further experiments (2 and 4) indicated that people rarely produced rankings when given a choice of assessment measures for either the length of lines or the artistic value of photographs. In Experiment 5, when the number of lines was larger or lines were only visible one at a time, participants were faster at estimating line lengths as a percentage of the card covered than at rank ordering the lengths. Overall, the results indicate that ordering stimuli is not an easy or natural process when the number of stimuli is large or when the stimuli are not all perceptible at once. An implication is that the psychological measures available to individuals are not likely to be purely ordinal when many of the elements being measured must be recalled.

  10. Stimuli-responsive polymer films.

    PubMed

    Zhai, Lei

    2013-09-01

    Stimuli-responsive polymer films undergo interesting structural and property changes upon external stimuli. Their applications have extended from smart coatings to controlled drug release, smart windows, self-repair and other fields. This tutorial review summarizes non-covalent bonding, reversible reactions and responsive molecules that have played important roles in creating stimuli-responsive systems, and presents the recent development of three types of responsive polymer systems: layer-by-layer polymer multilayer films, polymer brushes, and self-repairing polymer films, with a discussion of their response mechanism. Future research efforts include comprehensive understanding of the response mechanism, producing polymer systems with controlled response properties regarding single or multiple external signals, combining polymer film fabrication with nanotechnology, improving the stability of polymer films on substrates, and evaluating the toxicity of the degradation products. PMID:23749141

  11. The Composite Spectrum of BOSS Quasars Selected for Studies of the Lyα Forest

    NASA Astrophysics Data System (ADS)

    Harris, David W.; Jensen, Trey W.; Suzuki, Nao; Bautista, Julian E.; Dawson, Kyle S.; Vivek, M.; Brownstein, Joel R.; Ge, Jian; Hamann, Fred; Herbst, H.; Jiang, Linhua; Moran, Sarah E.; Myers, Adam D.; Olmstead, Matthew D.; Schneider, Donald P.

    2016-06-01

    The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 2.1 ≤ z ≤ 3.5 quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800-3300 Å at a signal-to-noise ratio close to 1000 per pixel (Δv of 69 km s-1). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to Sloan Digital Sky Survey (SDSS) photometry used in target selection. The quasar composite matches the color of the quasar population to 0.02 mag in g - r, 0.03 mag in r - i, and 0.01 mag in i - z over the redshift range 2.2 < z < 2.6. The composite spectrum deviates from the imaging photometry by 0.05 mag around z = 2.7, likely due to differences in target selection as the quasar colors become similar to the stellar locus at this redshift. Finally, we characterize the line features in the high signal-to-noise composite and identify nine faint lines not found in the previous composite spectrum from SDSS.

  12. Numerical study on the influence of boss cap fins on efficiency of controllable-pitch propeller

    NASA Astrophysics Data System (ADS)

    Xiong, Ying; Wang, Zhanzhi; Qi, Wanjiang

    2013-03-01

    Numerical simulation is investigated to disclose how propeller boss cap fins (PBCF) operate utilizing Reynolds-averaged Navier-Stokes (RANS) method. In addition, exploration of the influencing mechanism of PBCF on the open water efficiency of one controllable-pitch propeller is analyzed through the open water characteristic curves, blade surface pressure distribution and hub streamline distribution. On this basis, the influence of parameters including airfoil profile, diameter, axial position of installation and circumferential installation angle on the open water efficiency of the controllable-pitch propeller is investigated. Numerical results show: for the controllable-pitch propeller, the thrust generated is at the optimum when the radius of boss cap fins is 1.5 times of propeller hub with an optimal installation position in the axial direction, and its optimal circumferential installation position is the midpoint of the extension line of the front and back ends of two adjacent propeller roots in the front of fin root. Under these optimal parameters, the gain of open water efficiency of the controllable-pitch propeller with different advance velocity coefficients is greater than 0.01, which accounts for approximately an increase of 1%-5% of open water efficiency.

  13. Neural Processing of Emotional Musical and Nonmusical Stimuli in Depression

    PubMed Central

    Atchley, Ruth Ann; Chrysikou, Evangelia; Martin, Laura E.; Clair, Alicia A.; Ingram, Rick E.; Simmons, W. Kyle; Savage, Cary R.

    2016-01-01

    Background Anterior cingulate cortex (ACC) and striatum are part of the emotional neural circuitry implicated in major depressive disorder (MDD). Music is often used for emotion regulation, and pleasurable music listening activates the dopaminergic system in the brain, including the ACC. The present study uses functional MRI (fMRI) and an emotional nonmusical and musical stimuli paradigm to examine how neural processing of emotionally provocative auditory stimuli is altered within the ACC and striatum in depression. Method Nineteen MDD and 20 never-depressed (ND) control participants listened to standardized positive and negative emotional musical and nonmusical stimuli during fMRI scanning and gave subjective ratings of valence and arousal following scanning. Results ND participants exhibited greater activation to positive versus negative stimuli in ventral ACC. When compared with ND participants, MDD participants showed a different pattern of activation in ACC. In the rostral part of the ACC, ND participants showed greater activation for positive information, while MDD participants showed greater activation to negative information. In dorsal ACC, the pattern of activation distinguished between the types of stimuli, with ND participants showing greater activation to music compared to nonmusical stimuli, while MDD participants showed greater activation to nonmusical stimuli, with the greatest response to negative nonmusical stimuli. No group differences were found in striatum. Conclusions These results suggest that people with depression may process emotional auditory stimuli differently based on both the type of stimulation and the emotional content of that stimulation. This raises the possibility that music may be useful in retraining ACC function, potentially leading to more effective and targeted treatments. PMID:27284693

  14. Stimuli, Reinforcers, and Private Events

    ERIC Educational Resources Information Center

    Nevin, John A.

    2008-01-01

    Radical behaviorism considers private events to be a part of ongoing observable behavior and to share the properties of public events. Although private events cannot be measured directly, their roles in overt action can be inferred from mathematical models that relate private responses to external stimuli and reinforcers according to the same…

  15. Building a better understanding of the massive high-redshift BOSS CMASS galaxies as tools for cosmology

    NASA Astrophysics Data System (ADS)

    Favole, Ginevra; McBride, Cameron K.; Eisenstein, Daniel J.; Prada, Francisco; Swanson, Molly E.; Chuang, Chia-Hsun; Schneider, Donald P.

    2016-10-01

    We explore the massive bluer star-forming population of the Sloan Digital Sky Survey (SDSS) III/BOSS CMASS DR11 galaxies at z > 0.55 to quantify their differences, in terms of redshift-space distortions and large-scale bias, with respect to the luminous red galaxy sample. We perform a qualitative analysis to understand the significance of these differences and whether we can model and reproduce them in mock catalogues. Specifically, we measure galaxy clustering in CMASS on small and intermediate scales (0.1 ≲ r ≲ 50 h-1 Mpc) by computing the two-point correlation function - both projected and redshift-space - of these galaxies, and a new statistic, Σ(π), able to separate the coherent and dispersed redshift-space distortion contributions and the large-scale bias. We interpret our clustering measurements by adopting a Halo Occupation Distribution (HOD) scheme that maps them on to high-resolution N-body cosmological simulations to produce suitable mock galaxy catalogues. The traditional HOD prescription can be applied to the red and the blue samples, independently, but this approach is unphysical since it allows the same mock galaxies to be either red or blue. To overcome this ambiguity, we modify the standard formulation and infer the red and the blue models by splitting the full mock catalogue into two complementary and non-overlapping submocks. This separation is performed by constraining the HOD with the observed CMASS red and blue galaxy fractions and produces reliable and accurate models.

  16. Application of a BOSS-Gaussian interface for QM/MM simulations of Henry and methyl transfer reactions.

    PubMed

    Vilseck, Jonah Z; Kostal, Jakub; Tirado-Rives, Julian; Jorgensen, William L

    2015-10-15

    Hybrid quantum mechanics and molecular mechanics (QM/MM) computer simulations have become an indispensable tool for studying chemical and biological phenomena for systems too large to treat with QM alone. For several decades, semiempirical QM methods have been used in QM/MM simulations. However, with increased computational resources, the introduction of ab initio and density function methods into on-the-fly QM/MM simulations is being increasingly preferred. This adaptation can be accomplished with a program interface that tethers independent QM and MM software packages. This report introduces such an interface for the BOSS and Gaussian programs, featuring modification of BOSS to request QM energies and partial atomic charges from Gaussian. A customizable C-shell linker script facilitates the interprogram communication. The BOSS-Gaussian interface also provides convenient access to Charge Model 5 (CM5) partial atomic charges for multiple purposes including QM/MM studies of reactions. In this report, the BOSS-Gaussian interface is applied to a nitroaldol (Henry) reaction and two methyl transfer reactions in aqueous solution. Improved agreement with experiment is found by determining free-energy surfaces with MP2/CM5 QM/MM simulations than previously reported investigations using semiempirical methods.

  17. Frontal bossing

    MedlinePlus

    ... seen only in a few rare syndromes, including acromegaly, a long-term (chronic) disorder caused by too ... Causes include: Acromegaly Basal cell nevus syndrome Congenital ... syndrome Pfeiffer syndrome Rubinstein-Taybi syndrome Russell- ...

  18. Examining the ages of M7-L8 dwarfs with the BOSS Ultracool Dwarf sample

    NASA Astrophysics Data System (ADS)

    Schmidt, Sarah J.; Hawley, Suzanne L.; West, Andrew A.; Bochanski, John J.

    2016-01-01

    We present the latest results from the BOSS Ultracool Dwarfs (BUD) sample of 12998 M7-L8 dwarfs, identified from a combination of photometry and spectroscopy from the Sloan Digital Sky Survey (SDSS). Using a cross-match of the BUD sample to the Two Micron All-Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE) catalogs, we measure both colors and proper motions for the majority of the sample. The proper motions, combined with radial velocities from SDSS spectra and updated distance estimates based on i-Ks colors, yield three-dimensional velocities for 9121 ultracool dwarfs. We usethese velocities as statistical proxies for age to identify and test other potential age indicators, including Hα emission, atomic line strengths, molecular band depths, and broad-band colors.

  19. BigBOSS: The Ground-Based Stage IV BAO Experiment

    SciTech Connect

    Schlegel, David; Bebek, Chris; Heetderks, Henry; Ho, Shirley; Lampton, Michael; Levi, Michael; Mostek, Nick; Padmanabhan, Nikhil; Perlmutter, Saul; Roe, Natalie; Sholl, Michael; Smoot, George; White, Martin; Dey, Arjun; Abraham, Tony; Jannuzi, Buell; Joyce, Dick; Liang, Ming; Merrill, Mike; Olsen, Knut; Salim, Samir

    2009-04-01

    The BigBOSS experiment is a proposed DOE-NSF Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with an all-sky galaxy redshift survey. The project is designed to unlock the mystery of dark energy using existing ground-based facilities operated by NOAO. A new 4000-fiber R=5000 spectrograph covering a 3-degree diameter field will measure BAO and redshift space distortions in the distribution of galaxies and hydrogen gas spanning redshifts from 0.2< z< 3.5. The Dark Energy Task Force figure of merit (DETF FoM) for this experiment is expected to be equal to that of a JDEM mission for BAO with the lower risk and cost typical of a ground-based experiment.

  20. The experiment BOSS on EXPOSE R-2, Mission Preparation Tests for Biofilm Organisms Surfing Space

    NASA Astrophysics Data System (ADS)

    Panitz, C.; Rettberg, P.; Rabbow, E.; Bauermeister, A.; Barczyk, S.; Billi, D.; Cockell, Ch.; Flemming, H. C.; Stan-Lotter, H.; Venkateswaran, K.

    2012-09-01

    In the experiment BOSS the hypothesis will be tested if the biofilm form of life with microorganisms embedded and aggregated in their EPS matrix is suited to support long-term survival of microorganisms under the harsh environmental conditions as they exist in space and on Mars and is superior to the same bacteria in the form of planktonic cultures. An additional protective role may be provided by particles associated in biofilms which may shield the organisms against radiation. The experiment will be flown on EXPOSE R-2 attached outside of the ISS on the Russian module. The experiment has participated at the Experiment verification tests and a Science verification test which have been carried out in the Planetary and Space Simulation Facilities at DLR. The launch is scheduled for end of 2013.

  1. Mimicking biophysical stimuli within bone tumor microenvironment*

    PubMed Central

    Marturano-Kruik, A.; Yeager, K.; Bach, D.; Villasante, A.; Cimetta, E.; Vunjak-Novakovic, G.

    2016-01-01

    In vivo, cells reside in a complex environment regulating their fate and function. Most of this complexity is lacking in standard in vitro models, leading to readouts falling short of predicting the actual in vivo situation. The use of engineering tools, combined with deep biological knowledge, leads to the development and use of bioreactors providing biologically sound niches. Such bioreactors offer new tools for biological research, and are now also entering the field of cancer research. Here we present the development and validation of a modular bioreactor system providing: (i) high throughput analyses, (ii) a range of biological conditions, (iii) high degree of control, and (iv) application of physiological stimuli to the cultured samples. The bioreactor was used to engineer a three-dimensional (3D) tissue model of cancer, where the effects of mechanical stimulation on the tumor phenotype were evaluated. Mechanical stimuli applied to the engineered tumor model activated the mechanotransduction machinery and resulted in measurable changes of mRNA levels towards a more aggressive tumor phenotype. PMID:26737062

  2. Escape from serial stimuli leading to food

    PubMed Central

    Dinsmoor, James A.; Lee, Diana M.; Brown, Marceline M.

    1986-01-01

    If the functional relations governing the strength of a conditioned reinforcer correspond to those obtained with other Pavlovian procedures (e.g., Kaplan, 1984), the termination of stimuli appearing early in the interval between successive food deliveries should be reinforcing. During initial training we presented four key colors, followed by food, in a recurrent sequence to each of 6 pigeons. This established a baseline level of autoshaped pecking. In later sessions, we terminated each of these colors or only the first color for a brief period following each peck, replacing the original color with a standard substitute to avoid darkening the key. Pecking decreased in the presence of the last color in the sequence but increased in the presence of the first. In accord with contemporary models of Pavlovian conditioning, these and other data suggest that the behavioral effects of stimuli in a chain may be better understood in terms of what each stimulus predicts, as measured by relative time to the terminal reinforcer, than in the exclusively positive terms of the traditional formulation (Skinner, 1938). The same model may also account for the initial pause under fixed-interval and fixed-ratio schedules of reinforcement. PMID:16812462

  3. The Weak Lensing Signal and the Clustering of BOSS Galaxies. I. Measurements

    NASA Astrophysics Data System (ADS)

    Miyatake, Hironao; More, Surhud; Mandelbaum, Rachel; Takada, Masahiro; Spergel, David N.; Kneib, Jean-Paul; Schneider, Donald P.; Brinkmann, J.; Brownstein, Joel R.

    2015-06-01

    A joint analysis of the clustering of galaxies and their weak gravitational lensing signal is well-suited to simultaneously constrain the galaxy-halo connection as well as the cosmological parameters by breaking the degeneracy between galaxy bias and the amplitude of clustering signal. In a series of two papers, we perform such an analysis at the highest redshift (z˜ 0.53) in the literature using CMASS galaxies in the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Eleventh Data Release (BOSS DR11) catalog spanning 8300 deg2. In this paper, we present details of the clustering and weak lensing measurements of these galaxies. We define a subsample of 400,916 CMASS galaxies based on their redshifts and stellar-mass estimates so that the galaxies constitute an approximately volume-limited and similar population over the redshift range 0.47≤slant z≤slant 0.59. We obtain a signal-to-noise ratio (S/N) ≃ 56 for the galaxy clustering measurement. We also explore the redshift and stellar-mass dependence of the clustering signal. For the weak lensing measurement, we use existing deeper imaging data from the Canada-France-Hawaii Telescope Legacy Survey with publicly available shape and photometric redshift catalogs from CFHTLenS, but only in a 105 deg2 area that overlaps with BOSS. This restricts the lensing measurement to only 5084 CMASS galaxies. After careful systematic tests, we find a highly significant detection of the CMASS weak lensing signal, with total S/N ≃ 26. These measurements form the basis of the halo occupation distribution and cosmology analysis presented in More et al. (Paper II).

  4. THE BOSS Ly{alpha} FOREST SAMPLE FROM SDSS DATA RELEASE 9

    SciTech Connect

    Lee, Khee-Gan; Bailey, Stephen; Carithers, William; Schlegel, David J.; Bartsch, Leslie E.; Dawson, Kyle S.; Bolton, Adam S.; Kirkby, David; Margala, Daniel; Blomqvist, Michael; Lundgren, Britt; Palanque-Delabrouille, Nathalie; Yeche, Christophe; Borde, Arnaud; Weinberg, David H.; Aubourg, Eric; Bautista, Julian; and others

    2013-03-15

    We present the BOSS Lyman-{alpha} (Ly{alpha}) Forest Sample from SDSS Data Release 9, comprising 54,468 quasar spectra with z{sub qso} > 2.15 suitable for Ly{alpha} forest analysis. This data set probes the intergalactic medium with absorption redshifts 2.0 < z{sub {alpha}} < 5.7 over an area of 3275 deg{sup 2}, and encompasses an approximate comoving volume of 20 h {sup -3} Gpc{sup 3}. With each spectrum, we have included several products designed to aid in Ly{alpha} forest analysis: improved sky masks that flag pixels where data may be unreliable, corrections for known biases in the pipeline estimated noise, masks for the cores of damped Ly{alpha} systems and corrections for their wings, and estimates of the unabsorbed continua so that the observed flux can be converted to a fractional transmission. The continua are derived using a principal component fit to the quasar spectrum redward of rest-frame Ly{alpha} ({lambda} > 1216 A), extrapolated into the forest region and normalized by a linear function to fit the expected evolution of the Ly{alpha} forest mean flux. The estimated continuum errors are {approx}< 5% rms. We also discuss possible systematics arising from uncertain spectrophotometry and artifacts in the flux calibration; global corrections for the latter are provided. Our sample provides a convenient starting point for users to analyze clustering in BOSS Ly{alpha} forest data, and it provides a fiducial data set that can be used to compare results from different analyses of baryon acoustic oscillations in the Ly{alpha} forest. The full data set is available from the SDSS-III DR9 Web site.

  5. The BOSS Lyα Forest Sample from SDSS Data Release 9

    NASA Astrophysics Data System (ADS)

    Lee, Khee-Gan; Bailey, Stephen; Bartsch, Leslie E.; Carithers, William; Dawson, Kyle S.; Kirkby, David; Lundgren, Britt; Margala, Daniel; Palanque-Delabrouille, Nathalie; Pieri, Matthew M.; Schlegel, David J.; Weinberg, David H.; Yèche, Christophe; Aubourg, Éric; Bautista, Julian; Bizyaev, Dmitry; Blomqvist, Michael; Bolton, Adam S.; Borde, Arnaud; Brewington, Howard; Busca, Nicolás G.; Croft, Rupert A. C.; Delubac, Timothée; Ebelke, Garrett; Eisenstein, Daniel J.; Font-Ribera, Andreu; Ge, Jian; Hamilton, Jean-Christophe; Hennawi, Joseph F.; Ho, Shirley; Honscheid, Klaus; Le Goff, Jean-Marc; Malanushenko, Elena; Malanushenko, Viktor; Miralda-Escudé, Jordi; Myers, Adam D.; Noterdaeme, Pasquier; Oravetz, Daniel; Pan, Kaike; Pâris, Isabelle; Petitjean, Patrick; Rich, James; Rollinde, Emmanuel; Ross, Nicholas P.; Rossi, Graziano; Schneider, Donald P.; Simmons, Audrey; Snedden, Stephanie; Slosar, Anže; Spergel, David N.; Suzuki, Nao; Viel, Matteo; Weaver, Benjamin A.

    2013-03-01

    We present the BOSS Lyman-α (Lyα) Forest Sample from SDSS Data Release 9, comprising 54,468 quasar spectra with z qso > 2.15 suitable for Lyα forest analysis. This data set probes the intergalactic medium with absorption redshifts 2.0 < z α < 5.7 over an area of 3275 deg2, and encompasses an approximate comoving volume of 20 h -3 Gpc3. With each spectrum, we have included several products designed to aid in Lyα forest analysis: improved sky masks that flag pixels where data may be unreliable, corrections for known biases in the pipeline estimated noise, masks for the cores of damped Lyα systems and corrections for their wings, and estimates of the unabsorbed continua so that the observed flux can be converted to a fractional transmission. The continua are derived using a principal component fit to the quasar spectrum redward of rest-frame Lyα (λ > 1216 Å), extrapolated into the forest region and normalized by a linear function to fit the expected evolution of the Lyα forest mean flux. The estimated continuum errors are <~ 5% rms. We also discuss possible systematics arising from uncertain spectrophotometry and artifacts in the flux calibration; global corrections for the latter are provided. Our sample provides a convenient starting point for users to analyze clustering in BOSS Lyα forest data, and it provides a fiducial data set that can be used to compare results from different analyses of baryon acoustic oscillations in the Lyα forest. The full data set is available from the SDSS-III DR9 Web site.

  6. Clustering of intermediate redshift quasars using the final SDSS III-BOSS sample

    NASA Astrophysics Data System (ADS)

    Eftekharzadeh, Sarah; Myers, Adam D.; White, Martin; Weinberg, David H.; Schneider, Donald P.; Shen, Yue; Font-Ribera, Andreu; Ross, Nicholas P.; Paris, Isabelle; Streblyanska, Alina

    2015-11-01

    We measure the two-point clustering of spectroscopically confirmed quasars from the final sample of the Baryon Oscillation Spectroscopic Survey (BOSS) on comoving scales of 4 ≲ s ≲ 22 h-1 Mpc. The sample covers 6950 deg2 [ ˜ 19 (h- 1Gpc)3] and, over the redshift range 2.2 ≤ z ≤ 2.8, contains 55 826 homogeneously selected quasars, which is twice as many as in any similar work. We deduce bQ = 3.54 ± 0.10; the most precise measurement of quasar bias to date at these redshifts. This corresponds to a host halo mass of ˜2 × 1012 h-1 M⊙ with an implied quasar duty cycle of ˜1 per cent. The real-space projected correlation function is well fitted by a power law of index 2 and correlation length r0 = (8.12 ± 0.22) h- 1 Mpc over scales of 4 ≲ rp ≲ 25 h-1 Mpc. To better study the evolution of quasar clustering at moderate redshift, we extend the redshift range of our study to z ˜ 3.4 and measure the bias and correlation length of three subsamples over 2.2 ≤ z ≤ 3.4. We find no significant evolution of r0 or bias over this range, implying that the host halo mass of quasars decreases somewhat with increasing redshift. We find quasar clustering remains similar over a decade in luminosity, contradicting a scenario in which quasar luminosity is monotonically related to halo mass at z ≈ 2.5. Our results are broadly consistent with previous BOSS measurements, but they yield more precise constraints based upon a larger and more uniform data set.

  7. Redshift evolution of the dynamical properties of massive galaxies from SDSS-III/BOSS

    SciTech Connect

    Beifiori, Alessandra; Saglia, Roberto P.; Bender, Ralf; Senger, Robert; Thomas, Daniel; Maraston, Claudia; Steele, Oliver; Masters, Karen L.; Pforr, Janine; Tojeiro, Rita; Johansson, Jonas; Nichol, Robert C.; Chen, Yan-Mei; Wake, David; Bolton, Adam; Brownstein, Joel R.; Leauthaud, Alexie; Schneider, Donald P.; Skibba, Ramin; Pan, Kaike; and others

    2014-07-10

    We study the redshift evolution of the dynamical properties of ∼180, 000 massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy sample from SDSS-II in the redshift range 0.1 ≤ z ≤ 0.6. The typical stellar mass of this sample is M{sub *} ∼2 × 10{sup 11} M{sub ☉}. We analyze the evolution of the galaxy parameters effective radius, stellar velocity dispersion, and the dynamical to stellar mass ratio with redshift. As the effective radii of BOSS galaxies at these redshifts are not well resolved in the Sloan Digital Sky Survey (SDSS) imaging we calibrate the SDSS size measurements with Hubble Space Telescope/COSMOS photometry for a sub-sample of galaxies. We further apply a correction for progenitor bias to build a sample which consists of a coeval, passively evolving population. Systematic errors due to size correction and the calculation of dynamical mass are assessed through Monte Carlo simulations. At fixed stellar or dynamical mass, we find moderate evolution in galaxy size and stellar velocity dispersion, in agreement with previous studies. We show that this results in a decrease of the dynamical to stellar mass ratio with redshift at >2σ significance. By combining our sample with high-redshift literature data, we find that this evolution of the dynamical to stellar mass ratio continues beyond z ∼ 0.7 up to z > 2 as M{sub dyn}/M{sub *} ∼(1 + z){sup –0.30±0.12}, further strengthening the evidence for an increase of M{sub dyn}/M{sub *} with cosmic time. This result is in line with recent predictions from galaxy formation simulations based on minor merger driven mass growth, in which the dark matter fraction within the half-light radius increases with cosmic time.

  8. Emotional Stimuli and Motor Conversion Disorder

    ERIC Educational Resources Information Center

    Voon, Valerie; Brezing, Christina; Gallea, Cecile; Ameli, Rezvan; Roelofs, Karin; LaFrance, W. Curt, Jr.; Hallett, Mark

    2010-01-01

    Conversion disorder is characterized by neurological signs and symptoms related to an underlying psychological issue. Amygdala activity to affective stimuli is well characterized in healthy volunteers with greater amygdala activity to both negative and positive stimuli relative to neutral stimuli, and greater activity to negative relative to…

  9. Carpal boss in chronic wrist pain and its association with partial osseous coalition and osteoarthritis - A case report with focus on MRI findings.

    PubMed

    Poh, Feng

    2015-01-01

    The carpal boss is a bony prominence at the dorsal aspect of the 2(nd) and/or 3(rd) carpometacarpal joint, which has been linked to various etiologies, including trauma, os styloideum, osteophyte formation, and partial osseous coalition. It may result in symptoms through secondary degeneration, ganglion formation, bursitis, or extensor tendon abnormalities by altered biomechanics of wrist motion. We present a case of symptomatic carpal boss with the finding of a partial osseous coalition at the 2(nd) carpometacarpal (metacarpal-trapezoid) joint and highlight the magnetic resonance imaging (MRI) findings of carpal boss impingement and secondary osteoarthritis. To the best of our knowledge, there is no report in the literature describing the imaging findings of partial osseous coalition and degenerative osteoarthritis in relation to carpal boss.

  10. Enhanced brain susceptibility to negative stimuli in adolescents: ERP evidences

    PubMed Central

    Yuan, Jiajin; Ju, Enxia; Meng, Xianxin; Chen, Xuhai; Zhu, Siyu; Yang, Jiemin; Li, Hong

    2015-01-01

    Background: Previous studies investigated neural substrates of emotional face processing in adolescents and its comparison with adults. As emotional faces elicit more of emotional expression recognition rather than direct emotional responding, it remains undetermined how adolescents are different from adults in brain susceptibility to emotionally stressful stimuli. Methods: Event-Related Potentials (ERPs) were recorded for highly negative (HN), moderately negative (MN), and neutral pictures in 20 adolescents and 20 adults while subjects performed a standard/deviant distinction task by pressing different keys, irrespective of the emotionality of deviant stimuli. Results: Adolescents exhibited more negative amplitudes for HN vs. neutral pictures in N1 (100–150 ms), P2 (130–190 ms), N2 (210–290 ms), and P3 (360–440 ms) components. In addition, adolescents showed more negative amplitudes for MN compared to neutral pictures in N1, P2, and N2 components. By contrast, adults exhibited significant emotion effects for HN stimuli in N2 and P3 amplitudes but not in N1 and P2 amplitudes, and they did not exhibit a significant emotion effect for MN stimuli at all these components. In the 210–290 ms time interval, the emotion effect for HN stimuli was significant across frontal and central regions in adolescents, while this emotion effect was noticeable only in the central region for adults. Conclusions: Adolescents are more emotionally sensitive to negative stimuli compared to adults, regardless of the emotional intensity of the stimuli, possibly due to the immature prefrontal control system over the limbic emotional inputs during adolescence. PMID:25972790

  11. The Role of Active Exploration of 3D Face Stimuli on Recognition Memory of Facial Information

    ERIC Educational Resources Information Center

    Liu, Chang Hong; Ward, James; Markall, Helena

    2007-01-01

    Research on face recognition has mainly relied on methods in which observers are relatively passive viewers of face stimuli. This study investigated whether active exploration of three-dimensional (3D) face stimuli could facilitate recognition memory. A standard recognition task and a sequential matching task were employed in a yoked design.…

  12. Fitting methods for baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

    SciTech Connect

    Kirkby, David; Margala, Daniel; Blomqvist, Michael; Slosar, Anže; Bailey, Stephen; Carithers, Bill; Busca, Nicolás G.; Bautista, Julian E.; Brownstein, Joel R.; Dawson, Kyle S.; Croft, Rupert A.C.; Font-Ribera, Andreu; Miralda-Escudé, Jordi; Myers, Adam D.; Nichol, Robert C.; Pâris, Isabelle; Petitjean, Patrick; and others

    2013-03-01

    We describe fitting methods developed to analyze fluctuations in the Lyman-α forest and measure the parameters of baryon acoustic oscillations (BAO). We apply our methods to BOSS Data Release 9. Our method is based on models of the three-dimensional correlation function in physical coordinate space, and includes the effects of redshift-space distortions, anisotropic non-linear broadening, and broadband distortions. We allow for independent scale factors along and perpendicular to the line of sight to minimize the dependence on our assumed fiducial cosmology and to obtain separate measurements of the BAO angular and relative velocity scales. Our fitting software and the input files needed to reproduce our main BOSS Data Release 9 results are publicly available.

  13. BOSS on EXPOSE-R2-Comparative Investigations on Biofilm and Planktonic cells of Deinococcus geothermalis as Mission Preparation Tests

    NASA Astrophysics Data System (ADS)

    Panitz, C.; Rettberg, P.; Frösler, J.; Flemming, H.-C.; Rabbow, E.; Reitz, G.

    2013-09-01

    Biofilms are of interest for Astrobiological investigations since they are one of the oldest clear signs of life on Earth. In the experiment BOSS the hypothesis will be tested if the biofilm form of life with microorganisms embedded and aggregated in their EPS matrix is suited to support long-term survival of microorganisms under the harsh environmental conditions as they exist in space and on Mars and is superior to the same bacteria in the form of planktonic cultures. An additional protective role may be provided by particles associated in biofilms which may shield the organisms against radiation. The experiment will be flown on EXPOSE-R2 attached outside of the ISS on the Russian module. BOSS has participated the Experiment verification tests and will attend the upcoming Science verification test carried out in the Planetary and Space Simulation Facilities at DLR. The launch is scheduled for April 2014.

  14. Sloan Digital Sky Survey III (SDSS-III), Data Release 9, including the Baryon Oscillation Spectroscopic Survey (BOSS)

    DOE Data Explorer

    The Third Sloan Digital Sky Survey (SDSS-III) has issued Data Release 9 (DR9), the first public release of data from the Baryon Oscillation Spectroscopic Survey (BOSS). In this release BOSS, the largest of SDSS-III’s four surveys, provides spectra for 535,995 newly observed galaxies, 102,100 quasars, and 116,474 stars, plus new information about objects in previous Sloan surveys (SDSS-I and II). Spectroscopy yields a wealth of information about astronomical objects including their motion (called redshift and written z), their composition, and sometimes also the density of the gas and other material that lies between them and observers on Earth. The new release lists spectra for galaxies with redshifts up to z = 0.8 (roughly 7 billion light years away) and quasars with redshifts between z = 2.1 and 3.5 (from 10 to 11.5 billion light years away). When BOSS is complete it will have measured 1.5 million galaxies and at least 150,000 quasars, as well as many thousands of stars and other ancillary objects for scientific projects other than BOSS’s main goal. [extracts copied from LBL news release of August 8, 2012

  15. Tests of redshift-space distortions models in configuration space for the analysis of the BOSS final data release

    NASA Astrophysics Data System (ADS)

    White, Martin; Reid, Beth; Chuang, Chia-Hsun; Tinker, Jeremy L.; McBride, Cameron K.; Prada, Francisco; Samushia, Lado

    2015-02-01

    Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In preparation for analysis of redshift-space distortions from the Baryon Oscillation Spectroscopic Survey (BOSS) final data release, we compare a number of analytic and phenomenological models, specified in configuration space, to mock catalogues derived in different ways from several N-body simulations. The galaxies in each mock catalogue have properties similar to those of the higher redshift galaxies measured by BOSS but differ in the details of how small-scale velocities and halo occupancy are determined. We find that all of the analytic models fit the simulations over a limited range of scales while failing at small scales. We discuss which models are most robust and on which scales they return reliable estimates of the rate of growth of structure: we find that models based on some form of resummation can fit our N-body data for BOSS-like galaxies above 30 h-1 Mpc well enough to return unbiased parameter estimates.

  16. Happiness increases distraction by auditory deviant stimuli.

    PubMed

    Pacheco-Unguetti, Antonia Pilar; Parmentier, Fabrice B R

    2016-08-01

    Rare and unexpected changes (deviants) in an otherwise repeated stream of task-irrelevant auditory distractors (standards) capture attention and impair behavioural performance in an ongoing visual task. Recent evidence indicates that this effect is increased by sadness in a task involving neutral stimuli. We tested the hypothesis that such effect may not be limited to negative emotions but reflect a general depletion of attentional resources by examining whether a positive emotion (happiness) would increase deviance distraction too. Prior to performing an auditory-visual oddball task, happiness or a neutral mood was induced in participants by means of the exposure to music and the recollection of an autobiographical event. Results from the oddball task showed significantly larger deviance distraction following the induction of happiness. Interestingly, the small amount of distraction typically observed on the standard trial following a deviant trial (post-deviance distraction) was not increased by happiness. We speculate that happiness might interfere with the disengagement of attention from the deviant sound back towards the target stimulus (through the depletion of cognitive resources and/or mind wandering) but help subsequent cognitive control to recover from distraction. PMID:26302716

  17. Happiness increases distraction by auditory deviant stimuli.

    PubMed

    Pacheco-Unguetti, Antonia Pilar; Parmentier, Fabrice B R

    2016-08-01

    Rare and unexpected changes (deviants) in an otherwise repeated stream of task-irrelevant auditory distractors (standards) capture attention and impair behavioural performance in an ongoing visual task. Recent evidence indicates that this effect is increased by sadness in a task involving neutral stimuli. We tested the hypothesis that such effect may not be limited to negative emotions but reflect a general depletion of attentional resources by examining whether a positive emotion (happiness) would increase deviance distraction too. Prior to performing an auditory-visual oddball task, happiness or a neutral mood was induced in participants by means of the exposure to music and the recollection of an autobiographical event. Results from the oddball task showed significantly larger deviance distraction following the induction of happiness. Interestingly, the small amount of distraction typically observed on the standard trial following a deviant trial (post-deviance distraction) was not increased by happiness. We speculate that happiness might interfere with the disengagement of attention from the deviant sound back towards the target stimulus (through the depletion of cognitive resources and/or mind wandering) but help subsequent cognitive control to recover from distraction.

  18. Testing cosmology with a catalogue of voids in the BOSS galaxy surveys

    NASA Astrophysics Data System (ADS)

    Nadathur, Seshadri

    2016-09-01

    We present a public catalogue of voids in the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 11 LOWZ and CMASS galaxy surveys. This catalogue contains information on the location, sizes, densities, shapes and bounding surfaces of 8956 independent, disjoint voids, making it the largest public void catalogue to date. Voids are identified using a version of the ZOBOV algorithm, the operation of which has been calibrated though tests on mock galaxy populations in N-body simulations, as well as on a suite of 4096 mock catalogues which fully reproduce the galaxy clustering, survey masks and selection functions. Based on this, we estimate a false positive detection rate of 3 per cent. Comparison with mock catalogues limits deviations of the void size distribution from that predicted in the ΛCDM model to be less than 6 per cent for voids with effective radius 8 < Rv < 60 h-1Mpc and in the redshift range 0.15 < z < 0.7. This could tightly constrain modified gravity scenarios and models with a varying equation of state, but we identify systematic biases which must be accounted for to reduce the theoretical uncertainty in the predictions for these models to the current level of precision attained from the data. We also examine the distribution of void densities and identify a deficit of the deepest voids relative to ΛCDM expectations, which is significant at more than the 3σ equivalent level. We discuss possible explanations for this discrepancy but at present its cause remains unknown.

  19. Can the "stripping of the boss" be more than a joke?

    PubMed

    Laineste, Liisi

    2013-12-01

    In January 2011, uprisings and demonstrations broke out in Egypt, and the reverberations of the revolution are felt up to this day. The events that lead President Hosni Mubarak to resign were violent, disturbing, and definitely serious, but at the same time they were fuelled by and caused a plethora of jokes and funny slogans which circulated among the protesters. Previous studies on the functions of humour have suggested that among other things, humour can be used to enhance group cohesion by lifting up the spirits or to attack the (political) enemy by sharp sarcasm, the duality of which is captured in the metaphors of a shield and a sword. The present article builds upon "Stripping the Boss: The Powerful Role of Humor in the Egyptian Revolution 2011" by Helmy and Frerichs (2013), offering another perspective on the functionality Egyptian political jokes grounded in the current sociological approaches to humour. It aims to argue that humour as an ambiguous phenomenon is unreliable in reaching serious aims and thus cannot be conceptualised as a predictably functioning tool in conflicts, although it can sometimes give insights into the functioning of a society as a mirror of the social reality. PMID:24114264

  20. Intrinsic alignments of BOSS LOWZ galaxies - II. Impact of shape measurement methods

    NASA Astrophysics Data System (ADS)

    Singh, Sukhdeep; Mandelbaum, Rachel

    2016-04-01

    Measurements of intrinsic alignments of galaxy shapes with the large-scale density field, and the inferred intrinsic alignments model parameters, are sensitive to the shape measurement methods used. In this paper, we measure the intrinsic alignments of the Sloan Digital Sky Survey-III (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) low redshift (LOWZ) galaxies using three different shape measurement methods (re-Gaussianization, isophotal, and de Vaucouleurs), identifying a variation in the inferred intrinsic alignments amplitude at the 40 per cent level between these methods, independent of the galaxy luminosity or other properties. We also carry out a suite of systematics tests on the shapes and their two-point correlation functions, identifying a pronounced contribution from additive point spread function systematics in the de Vaucouleurs shapes. Since different methods measure galaxy shapes at different effective radii, the trends we identify in the intrinsic alignments amplitude are consistent with the interpretation that the outer regions of galaxy shapes are more responsive to tidal fields, resulting in isophote twisting and stronger alignments for isophotal shapes. We observe environment dependence of ellipticity, with brightest galaxies in groups being rounder on average compared to satellite and field galaxies. We also study the anisotropy in intrinsic alignments measurements introduced by projected shapes, finding effects consistent with predictions of the non-linear alignment model and hydrodynamic simulations. The large variations seen using the different shape measurement methods have important implications for intrinsic alignments forecasting and mitigation with future surveys.

  1. Exposure to virtual social stimuli modulates subjective pain reports

    PubMed Central

    Vigil, Jacob M; Torres, Daniel; Wolff, Alexander; Hughes, Katy

    2014-01-01

    BACKGROUND: Contextual factors, including the gender of researchers, influence experimental and patient pain reports. It is currently not known how social stimuli influence pain percepts, nor which types of sensory modalities of communication, such as auditory, visual or olfactory cues associated with person perception and gender processing, produce these effects. OBJECTIVES: To determine whether exposure to two forms of social stimuli (audio and visual) from a virtual male or female stranger modulates cold pressor task (CPT) pain reports. METHODS: Participants with similar demographic characteristics conducted a CPT in solitude, without the physical presence of an experimenter or another person. During the CPT, participants were exposed to the voice and image of a virtual male or female stranger. The voices had analogous vocal prosody, provided no semantic information (spoken in a foreign language) and differed only in pitch; the images depicted a middle-age male or female health care practitioner. RESULTS: Male participants, but not females, showed higher CPT pain intensity when they were exposed to the female stimuli compared with the male stimuli. Follow-up analyses showed that the association between the social stimuli and variability in pain sensitivity was not moderated by individual differences in subjective (eg, self-image) or objective measurements of one’s physical stature. DISCUSSION: The findings show that exposure to virtual, gender-based auditory and visual social stimuli influences exogenous pain sensitivity. CONCLUSION: Further research on how contextual factors, such as the vocal properties of health care examiners and exposure to background voices, may influence momentary pain perception is necessary for creating more standardized methods for measuring patient pain reports in clinical settings. PMID:24911175

  2. Visual stimuli: past and present

    NASA Astrophysics Data System (ADS)

    Westheimer, Gerald

    2013-03-01

    The fundamental properties of light and the principles of the structure and function of the visual system were discovered at a time when the only light sources were the sun and the flame of a candle. Contributions by Newton, Huygens, Thomas Young and Purkinje, Helmholtz's ophthalmoscope - all preceded the first incandescent filament. Light bulbs, Xenon arcs, lasers, light-emitting diodes (LEDs), computer monitors then sequentially enlarged the arsenal, and so did the steps from Nicol prism to Polaroid in polarizing light, and from glass and interference filters to laser light in generating monochromatic light. Technological advances have a deep impact on the research topics at any one time, expanding their scope. In particular, utilization of computers now allows the generation and manipulation of targets permitting questions to be approached that could not have been envisaged at the dawn of the technological era of vision research. Just beyond the immediate grasp of even the most thoughtful vision scientist, however, is the concern that stimulus sets originating in mathematicians' and physicists' toolboxes fail to capture some essential ingredients indigenous to human vision. The quest to study vision with stimuli in its own terms continues.

  3. Cardiorespiratory interactions to external stimuli.

    PubMed

    Bernardi, L; Porta, C; Spicuzza, L; Sleight, P

    2005-09-01

    Respiration is a powerful modulator of heart rate variability, and of baro- or chemo-reflex sensitivity. This occurs via a mechanical effect of breathing that synchronizes all cardiovascular variables at the respiratory rhythm, particularly when this occurs at a particular slow rate coincident with the Mayer waves in arterial pressure (approximately 6 cycles/min). Recitation of the rosary prayer (or of most mantras), induces a marked enhancement of these slow rhythms, whereas random verbalization or random breathing does not. This phenomenon in turn increases baroreflex sensitivity and reduces chemoreflex sensitivity, leading to increases in parasympathetic and reductions in sympathetic activity. The opposite can be seen during either verbalization or mental stress tests. Qualitatively similar effects can be obtained even by passive listening to more or less rhythmic auditory stimuli, such as music, and the speed of the rhythm (rather than the style) appears to be one of the main determinants of the cardiovascular and respiratory responses. These findings have clinical relevance. Appropriate modulation of breathing, can improve/restore autonomic control of cardiovascular and respiratory systems in relevant diseases such as hypertension and heart failure, and might therefore help improving exercise tolerance, quality of life, and ultimately, survival.

  4. THE BOSS EMISSION-LINE LENS SURVEY (BELLS). I. A LARGE SPECTROSCOPICALLY SELECTED SAMPLE OF LENS GALAXIES AT REDSHIFT {approx}0.5

    SciTech Connect

    Brownstein, Joel R.; Bolton, Adam S.; Pandey, Parul; Schlegel, David J.; Eisenstein, Daniel J.; Kochanek, Christopher S.; Connolly, Natalia; Maraston, Claudia; Seitz, Stella; Wake, David A.; Wood-Vasey, W. Michael; Brinkmann, Jon; Schneider, Donald P.; Weaver, Benjamin A.

    2012-01-01

    We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 {approx}< z {approx}< 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution.

  5. Binocular coordination in response to stereoscopic stimuli

    NASA Astrophysics Data System (ADS)

    Liversedge, Simon P.; Holliman, Nicolas S.; Blythe, Hazel I.

    2009-02-01

    Humans actively explore their visual environment by moving their eyes. Precise coordination of the eyes during visual scanning underlies the experience of a unified perceptual representation and is important for the perception of depth. We report data from three psychological experiments investigating human binocular coordination during visual processing of stereoscopic stimuli.In the first experiment participants were required to read sentences that contained a stereoscopically presented target word. Half of the word was presented exclusively to one eye and half exclusively to the other eye. Eye movements were recorded and showed that saccadic targeting was uninfluenced by the stereoscopic presentation, strongly suggesting that complementary retinal stimuli are perceived as a single, unified input prior to saccade initiation. In a second eye movement experiment we presented words stereoscopically to measure Panum's Fusional Area for linguistic stimuli. In the final experiment we compared binocular coordination during saccades between simple dot stimuli under 2D, stereoscopic 3D and real 3D viewing conditions. Results showed that depth appropriate vergence movements were made during saccades and fixations to real 3D stimuli, but only during fixations on stereoscopic 3D stimuli. 2D stimuli did not induce depth vergence movements. Together, these experiments indicate that stereoscopic visual stimuli are fused when they fall within Panum's Fusional Area, and that saccade metrics are computed on the basis of a unified percept. Also, there is sensitivity to non-foveal retinal disparity in real 3D stimuli, but not in stereoscopic 3D stimuli, and the system responsible for binocular coordination responds to this during saccades as well as fixations.

  6. Probing the circumgalactic medium at high-redshift using composite BOSS spectra of strong Lyman α forest absorbers

    NASA Astrophysics Data System (ADS)

    Pieri, Matthew M.; Mortonson, Michael J.; Frank, Stephan; Crighton, Neil; Weinberg, David H.; Lee, Khee-Gan; Noterdaeme, Pasquier; Bailey, Stephen; Busca, Nicolas; Ge, Jian; Kirkby, David; Lundgren, Britt; Mathur, Smita; Pâris, Isabelle; Palanque-Delabrouille, Nathalie; Petitjean, Patrick; Rich, James; Ross, Nicholas P.; Schneider, Donald P.; York, Donald G.

    2014-06-01

    We present composite spectra constructed from a sample of 242 150 Lyman α (Lyα) forest absorbers at redshifts 2.4 < z < 3.1 identified in quasar spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) as part of Data Release 9 of the Sloan Digital Sky Survey III. We select forest absorbers by their flux in bins 138 km s-1 wide (approximately the size of the BOSS resolution element). We split these absorbers into five samples spanning the range of flux -0.05 ≤ F < 0.45. Tests on a smaller set of high-resolution spectra show that our three strongest absorption samples would probe circumgalactic regions (projected separation <300 proper kpc and |Δv| < 300 km s-1) in about 60 per cent of cases for very high signal-to-noise ratio. Within this subset, weakening Lyα absorption is associated with decreasing purity of circumgalactic selection once BOSS noise is included. Our weaker two Lyα absorption samples are dominated by the intergalactic medium. We present composite spectra of these samples and a catalogue of measured absorption features from H I and 13 metal ionization species, all of which we make available to the community. We compare measurements of seven Lyman series transitions in our composite spectra to single line models and obtain further constraints from their associated excess Lyman limit opacity. This analysis provides results consistent with column densities over the range 14.4 ≲ log (N_{H I}) ≲ 16.45. We compare our measurements of metal absorption to a variety of simple single-line, single-phase models for a preliminary interpretation. Our results imply clumping on scales down to ˜30 pc and near-solar metallicities in the circumgalactic samples, while high-ionization metal absorption consistent with typical IGM densities and metallicities is visible in all samples.

  7. Stimuli, Reinforcers, and the Persistence of Behavior

    ERIC Educational Resources Information Center

    Nevin, John A.

    2009-01-01

    This article reviews evidence from basic and translational research with pigeons and humans suggesting that the persistence of operant behavior depends on the contingency between stimuli and reinforcers, and considers some implications for clinical interventions. (Contains 4 figures.)

  8. Emotional stimuli and motor conversion disorder.

    PubMed

    Voon, Valerie; Brezing, Christina; Gallea, Cecile; Ameli, Rezvan; Roelofs, Karin; LaFrance, W Curt; Hallett, Mark

    2010-05-01

    Conversion disorder is characterized by neurological signs and symptoms related to an underlying psychological issue. Amygdala activity to affective stimuli is well characterized in healthy volunteers with greater amygdala activity to both negative and positive stimuli relative to neutral stimuli, and greater activity to negative relative to positive stimuli. We investigated the relationship between conversion disorder and affect by assessing amygdala activity to affective stimuli. We conducted a functional magnetic resonance imaging study using a block design incidental affective task with fearful, happy and neutral face stimuli and compared valence contrasts between 16 patients with conversion disorder and 16 age- and gender-matched healthy volunteers. The patients with conversion disorder had positive movements such as tremor, dystonia or gait abnormalities. We also assessed functional connectivity between the amygdala and regions associated with motor preparation. A group by affect valence interaction was observed. Post hoc analyses revealed that whereas healthy volunteers had greater right amygdala activity to fearful versus neutral compared with happy versus neutral as expected, there were no valence differences in patients with conversion disorder. There were no group differences observed. The time course analysis also revealed greater right amygdala activity in patients with conversion disorder for happy stimuli (t = 2.96, P = 0.006) (with a trend for fearful stimuli, t = 1.81, P = 0.08) compared with healthy volunteers, with a pattern suggestive of impaired amygdala habituation even when controlling for depressive and anxiety symptoms. Using psychophysiological interaction analysis, patients with conversion disorder had greater functional connectivity between the right amygdala and the right supplementary motor area during both fearful versus neutral, and happy versus neutral 'stimuli' compared with healthy volunteers. These results were confirmed with

  9. Application of a BOSS – Gaussian Interface for QM/MM Simulations of Henry and Methyl Transfer Reactions

    PubMed Central

    Vilseck, Jonah Z.; Kostal, Jakub; Tirado-Rives, Julian; Jorgensen, William L.

    2015-01-01

    Hybrid quantum mechanics and molecular mechanics (QM/MM) computer simulations have become an indispensable tool for studying chemical and biological phenomena for systems too large to treat with quantum mechanics alone. For several decades, semi-empirical QM methods have been used in QM/MM simulations. However, with increased computational resources, the introduction of ab initio and density function methods into on-the-fly QM/MM simulations is being increasingly preferred. This adaptation can be accomplished with a program interface that tethers independent QM and MM software packages. This report introduces such an interface for the BOSS and Gaussian programs, featuring modification of BOSS to request QM energies and partial atomic charges from Gaussian. A customizable C-shell linker script facilitates the inter-program communication. The BOSS–Gaussian interface also provides convenient access to Charge Model 5 (CM5) partial atomic charges for multiple purposes including QM/MM studies of reactions. In this report, the BOSS–Gaussian interface is applied to a nitroaldol (Henry) reaction and two methyl transfer reactions in aqueous solution. Improved agreement with experiment is found by determining free-energy surfaces with MP2/CM5 QM/MM simulations than previously reported investigations employing semiempirical methods. PMID:26311531

  10. The large-scale cross-correlation of Damped Lyman alpha systems with the Lyman alpha forest: first measurements from BOSS

    SciTech Connect

    Font-Ribera, Andreu; Miralda-Escudé, Jordi; Arnau, Eduard; Carithers, Bill; Ross, Nicholas P.; White, Martin; Lee, Khee-Gan; Noterdaeme, Pasquier; Pâris, Isabelle; Petitjean, Patrick; Rollinde, Emmanuel; Rich, James; Schneider, Donald P.; York, Donald G. E-mail: miralda@icc.ub.edu

    2012-11-01

    We present the first measurement of the large-scale cross-correlation of Lyα forest absorption and Damped Lyman α systems (DLA), using the 9th Data Release of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is clearly detected on scales up to 40h{sup −1}Mpc and is well fitted by the linear theory prediction of the standard Cold Dark Matter model of structure formation with the expected redshift distortions, confirming its origin in the gravitational evolution of structure. The amplitude of the DLA-Lyα cross-correlation depends on only one free parameter, the bias factor of the DLA systems, once the Lyα forest bias factors are known from independent Lyα forest correlation measurements. We measure the DLA bias factor to be b{sub D} = (2.17±0.20)β{sub F}{sup 0.22}, where the Lyα forest redshift distortion parameter β{sub F} is expected to be above unity. This bias factor implies a typical host halo mass for DLAs that is much larger than expected in present DLA models, and is reproduced if the DLA cross section scales with halo mass as M{sub h}{sup α}, with α = 1.1±0.1 for β{sub F} = 1. Matching the observed DLA bias factor and rate of incidence requires that atomic gas remains extended in massive halos over larger areas than predicted in present simulations of galaxy formation, with typical DLA proper sizes larger than 20 kpc in host halos of masses ∼ 10{sup 12}M{sub ☉}. We infer that typical galaxies at z ≅ 2 to 3 are surrounded by systems of atomic clouds that are much more extended than the luminous parts of galaxies and contain ∼ 10% of the baryons in the host halo.

  11. [Segmentation, grouping and accentuation during stimuli perception].

    PubMed

    Sokolov, E N; Nezlina, N I

    2009-01-01

    The paper is concerned with grouping, segmentation and accentuation occurring in the processes of stimuli perception. An universal model of these events is based on vector coding in neuronal networks. Grouping is unification of objects or events into collections according to their similarity. Segmentation is separation of such groups up to small ensembles of units. In neuroscience grouping and segmentation are regarded as referred to neural mechanisms underlying perceptual and semantic processes resulting in a phenomenal attachment or separation. It is assumed that stimuli in neuronal nets are encoded by combinations of excitations of cardinal neurons constituting excitation vectors. Differences among stimuli are formed as absolute values of their excitation vector differences. The more different are stimuli the separate are their perceptual and semantic representations. The more similar are respective stimuli, the less is their separation. It suggests that stimuli having similar excitation vectors would be grouped together. On the contrary stimuli with opposed excitation vectors would be segmented and pushed to different ensembles. The vector encoding is expressed also for location in space. Thus spatial separation of objects is increasing with the increasing of their spatial excitation vector differences. The universal principle of vector encoding of differences can be illustrated by color contrast: differences of contrast colors rise with increase of their excitation vector differences. Objects having similar excitation vectors constitute a group accentuated due to summation of their excitation vectors. Groups of objects characterized by different excitation vectors are mutually accentuated by a contrast mechanism. A plastic accentuation depends on novelty of stimulation being habituated during repeated stimulus presentations.

  12. Short term memory for tactile stimuli.

    PubMed

    Gallace, Alberto; Tan, Hong Z; Haggard, Patrick; Spence, Charles

    2008-01-23

    Research has shown that unreported information stored in rapidly decaying visual representations may be accessed more accurately using partial report than using full report procedures (e.g., [Sperling, G., 1960. The information available in brief visual presentations. Psychological Monographs, 74, 1-29.]). In the 3 experiments reported here, we investigated whether unreported information regarding the actual number of tactile stimuli presented in parallel across the body surface can be accessed using a partial report procedure. In Experiment 1, participants had to report the total number of stimuli in a tactile display composed of up to 6 stimuli presented across their body (numerosity task), or else to detect whether or not a tactile stimulus had previously been presented in a position indicated by a visual probe given at a variable delay after offset of a tactile display (i.e., partial report). The results showed that participants correctly reported up to 3 stimuli in the numerosity judgment task, but their performance was significantly better than chance when up to 5 stimuli were presented in the partial report task. This result shows that short-lasting tactile representations can be accessed using partial report procedures similar to those used previously in visual studies. Experiment 2 showed that the duration of these representations (or the time available to consciously access them) depends on the number of stimuli presented in the display (the greater the number of stimuli that are presented, the faster their representation decays). Finally, the results of a third experiment showed that the differences in performance between the numerosity judgment and partial report tasks could not be explained solely in terms of any difference in task difficulty. PMID:18083147

  13. NESSTI: Norms for Environmental Sound Stimuli

    PubMed Central

    Hocking, Julia; Dzafic, Ilvana; Kazovsky, Maria; Copland, David A.

    2013-01-01

    In this paper we provide normative data along multiple cognitive and affective variable dimensions for a set of 110 sounds, including living and manmade stimuli. Environmental sounds are being increasingly utilized as stimuli in the cognitive, neuropsychological and neuroimaging fields, yet there is no comprehensive set of normative information for these type of stimuli available for use across these experimental domains. Experiment 1 collected data from 162 participants in an on-line questionnaire, which included measures of identification and categorization as well as cognitive and affective variables. A subsequent experiment collected response times to these sounds. Sounds were normalized to the same length (1 second) in order to maximize usage across multiple paradigms and experimental fields. These sounds can be freely downloaded for use, and all response data have also been made available in order that researchers can choose one or many of the cognitive and affective dimensions along which they would like to control their stimuli. Our hope is that the availability of such information will assist researchers in the fields of cognitive and clinical psychology and the neuroimaging community in choosing well-controlled environmental sound stimuli, and allow comparison across multiple studies. PMID:24023866

  14. Recall and recognition hypermnesia for Socratic stimuli.

    PubMed

    Kazén, Miguel; Solís-Macías, Víctor M

    2016-01-01

    In two experiments, we investigate hypermnesia, net memory improvements with repeated testing of the same material after a single study trial. In the first experiment, we found hypermnesia across three trials for the recall of word solutions to Socratic stimuli (dictionary-like definitions of concepts) replicating Erdelyi, Buschke, and Finkelstein and, for the first time using these materials, for their recognition. In the second experiment, we had two "yes/no" recognition groups, a Socratic stimuli group presented with concrete and abstract verbal materials and a word-only control group. Using signal detection measures, we found hypermnesia for concrete Socratic stimuli-and stable performance for abstract stimuli across three recognition tests. The control group showed memory decrements across tests. We interpret these findings with the alternative retrieval pathways (ARP) hypothesis, contrasting it with alternative theories of hypermnesia, such as depth of processing, generation and retrieve-recognise. We conclude that recognition hypermnesia for concrete Socratic stimuli is a reliable phenomenon, which we found in two experiments involving both forced-choice and yes/no recognition procedures.

  15. Stimuli-responsive materials in analytical separation.

    PubMed

    Lorenzo, Rosa A; Carro, Antonia M; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2015-07-01

    This review focuses on the fundamentals of stimuli-responsive materials and their applications to three common separation techniques, namely extraction, chromatography, and electrophoresis. Although still little investigated, materials that switch their affinity for the analyte on and off as a function of tiny changes in physical and biochemical variables offer relevant advantages for analyte extraction, concentration, and separation. Temperature and/or pH-responsive polymers in the form of chains or networks, which are dispersed in the sample as free entities or after being grafted onto beads (which may incorporate magnetic cores), enable quantitative capture and/or elution of the analyte under mild conditions and without needing organic solvents. Regarding liquid-chromatography separation, responsive stationary phases enable the implementation of "all-in-water" procedures in which retention times are modulated by means of temperature or pH gradients. Other stimuli that can be externally applied, for example light or magnetic fields, can also be used for efficient extraction or separation of the target substance without altering the composition of the sample matrix. Moreover, stimuli-responsiveness enables straightforward recycling of solid and/or stationary phases for a prolonged lifetime. Improved understanding of the phase transitions of stimuli-responsive materials and design of suitable formats for analytical applications should enable wider and more successful application of stimuli-responsive materials in analytical separations. PMID:25910881

  16. Lack of sleep affects the evaluation of emotional stimuli.

    PubMed

    Tempesta, Daniela; Couyoumdjian, Alessandro; Curcio, Giuseppe; Moroni, Fabio; Marzano, Cristina; De Gennaro, Luigi; Ferrara, Michele

    2010-04-29

    Sleep deprivation (SD) negatively affects various cognitive performances, but surprisingly evidence about a specific impact of sleep loss on subjective evaluation of emotional stimuli remains sparse. In the present study, we assessed the effect of SD on the emotional rating of standardized visual stimuli selected from the International Affective Picture System. Forty university students were assigned to the sleep group (n=20), tested before and after one night of undisturbed sleep at home, or to the deprivation group, tested before and after one night of total SD. One-hundred and eighty pictures (90 test, 90 retest) were selected and categorized as pleasant, neutral and unpleasant. Participants were asked to judge their emotional reactions while viewing pictures by means of the Self-Assessment Manikin. Subjective mood ratings were also obtained by means of Visual Analog Scales. No significant effect of SD was observed on the evaluation of pleasant and unpleasant stimuli. On the contrary, SD subjects perceived the neutral pictures more negatively and showed an increase of negative mood and a decrease of subjective alertness compared to non-deprived subjects. Finally, an analysis of covariance on mean valence ratings of neutral pictures using negative mood as covariate confirmed the effect of SD. Our results indicate that sleep is involved in regulating emotional evaluation. The emotional labeling of neutral stimuli biased toward negative responses was not mediated by the increase of negative mood. This effect can be interpreted as an adaptive reaction supporting the "better safe than sorry" principle. It may also have applied implications for healthcare workers, military and law-enforcement personnel.

  17. Lack of sleep affects the evaluation of emotional stimuli.

    PubMed

    Tempesta, Daniela; Couyoumdjian, Alessandro; Curcio, Giuseppe; Moroni, Fabio; Marzano, Cristina; De Gennaro, Luigi; Ferrara, Michele

    2010-04-29

    Sleep deprivation (SD) negatively affects various cognitive performances, but surprisingly evidence about a specific impact of sleep loss on subjective evaluation of emotional stimuli remains sparse. In the present study, we assessed the effect of SD on the emotional rating of standardized visual stimuli selected from the International Affective Picture System. Forty university students were assigned to the sleep group (n=20), tested before and after one night of undisturbed sleep at home, or to the deprivation group, tested before and after one night of total SD. One-hundred and eighty pictures (90 test, 90 retest) were selected and categorized as pleasant, neutral and unpleasant. Participants were asked to judge their emotional reactions while viewing pictures by means of the Self-Assessment Manikin. Subjective mood ratings were also obtained by means of Visual Analog Scales. No significant effect of SD was observed on the evaluation of pleasant and unpleasant stimuli. On the contrary, SD subjects perceived the neutral pictures more negatively and showed an increase of negative mood and a decrease of subjective alertness compared to non-deprived subjects. Finally, an analysis of covariance on mean valence ratings of neutral pictures using negative mood as covariate confirmed the effect of SD. Our results indicate that sleep is involved in regulating emotional evaluation. The emotional labeling of neutral stimuli biased toward negative responses was not mediated by the increase of negative mood. This effect can be interpreted as an adaptive reaction supporting the "better safe than sorry" principle. It may also have applied implications for healthcare workers, military and law-enforcement personnel. PMID:20117179

  18. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

    Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

    1975-01-01

    Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

  19. Comparing Identification of Standardized and Regionally Valid Vowels

    ERIC Educational Resources Information Center

    Wright, Richard; Souza, Pamela

    2012-01-01

    Purpose: In perception studies, it is common to use vowel stimuli from standardized recordings or synthetic stimuli created using values from well-known published research. Although the use of standardized stimuli is convenient, unconsidered dialect and regional accent differences may introduce confounding effects. The goal of this study was to…

  20. A dense array stimulator to generate arbitrary spatio-temporal tactile stimuli

    PubMed Central

    Killebrew, Justin H.; Bensmaïa, Sliman J.; Dammann, John F.; Denchev, Peter; Hsiao, Steven S.; Craig, James C.

    2007-01-01

    The generation and presentation of tactile stimuli presents a unique challenge. Unlike vision and audition, in which standard equipment such as monitors and audio systems can be used for most experiments, tactile stimuli and/or stimulators often have to be tailor-made for a given study. Here, we present a novel tactile stimulator designed to present arbitrary spatio-temporal stimuli to the skin. The stimulator consists of 400 pins, arrayed over a 1 cm2 area, each under independent computer control. The dense array allows for an unprecedented number of stimuli to be presented within an experimental session (e.g., up to 1200 stimuli per minute) and for stimuli to be generated adaptively. The stimulator can be used in a variety of modes and can deliver indented and scanned patterns as well as stimuli defined by mathematical spatio-temporal functions (e.g., drifting sinusoids). We describe the hardware and software of the system, and discuss previous and prospective applications. PMID:17134760

  1. The BOSS Emission-Line Lens Survey (BELLS). I. A Large Spectroscopically Selected Sample of Lens Galaxies at Redshift ~0.5

    NASA Astrophysics Data System (ADS)

    Brownstein, Joel R.; Bolton, Adam S.; Schlegel, David J.; Eisenstein, Daniel J.; Kochanek, Christopher S.; Connolly, Natalia; Maraston, Claudia; Pandey, Parul; Seitz, Stella; Wake, David A.; Wood-Vasey, W. Michael; Brinkmann, Jon; Schneider, Donald P.; Weaver, Benjamin A.

    2012-01-01

    We present a catalog of 25 definite and 11 probable strong galaxy-galaxy gravitational lens systems with lens redshifts 0.4 <~ z <~ 0.7, discovered spectroscopically by the presence of higher-redshift emission lines within the Baryon Oscillation Spectroscopic Survey (BOSS) of luminous galaxies, and confirmed with high-resolution Hubble Space Telescope (HST) images of 44 candidates. Our survey extends the methodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS) to higher redshift. We describe the details of the BOSS spectroscopic candidate detections, our HST ACS image processing and analysis methods, and our strong gravitational lens modeling procedure. We report BOSS spectroscopic parameters and ACS photometric parameters for all candidates, and mass-distribution parameters for the best-fit singular isothermal ellipsoid models of definite lenses. Our sample to date was selected using only the first six months of BOSS survey-quality spectroscopic data. The full five-year BOSS database should produce a sample of several hundred strong galaxy-galaxy lenses and in combination with SLACS lenses at lower redshift, strongly constrain the redshift evolution of the structure of elliptical, bulge-dominated galaxies as a function of luminosity, stellar mass, and rest-frame color, thereby providing a powerful test for competing theories of galaxy formation and evolution. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 12209. Based on spectroscopic data from the Baryon Oscillation Spectroscopic Survey of the Sloan Digital Sky Survey III.

  2. Verbal Establishing Stimuli: Testing the Motivative Effect of Stimuli in a Derived Relation with Consequences

    ERIC Educational Resources Information Center

    Ju, Winifred C.; Hayes, Steven C.

    2008-01-01

    The present study examined whether the presentation of stimuli in equivalence relations with consequences increases the operant behavior that produces these consequences. In Experiment 1, both normal words and experimentally trained equivalence stimuli did so with young children. In Experiment 2, results were similar with college students. Here, a…

  3. The perception of isoluminant coloured stimuli of amblyopic eye and defocused eye

    NASA Astrophysics Data System (ADS)

    Krumina, Gunta; Ozolinsh, Maris; Ikaunieks, Gatis

    2008-09-01

    In routine eye examination the visual acuity usually is determined using standard charts with black letters on a white background, however contrast and colour are important characteristics of visual perception. The purpose of research was to study the perception of isoluminant coloured stimuli in the cases of true and simulated amlyopia. We estimated difference in visual acuity with isoluminant coloured stimuli comparing to that for high contrast black-white stimuli for true amblyopia and simulated amblyopia. Tests were generated on computer screen. Visual acuity was detected using different charts in two ways: standard achromatic stimuli (black symbols on a white background) and isoluminant coloured stimuli (white symbols on a yellow background, grey symbols on blue, green or red background). Thus isoluminant tests had colour contrast only but had no luminance contrast. Visual acuity evaluated with the standard method and colour tests were studied for subjects with good visual acuity, if necessary using the best vision correction. The same was performed for subjects with defocused eye and with true amblyopia. Defocus was realized with optical lenses placed in front of the normal eye. The obtained results applying the isoluminant colour charts revealed worsening of the visual acuity comparing with the visual acuity estimated with a standard high contrast method (black symbols on a white background).

  4. Non-target adjacent stimuli classification improves performance of classical ERP-based brain computer interface

    NASA Astrophysics Data System (ADS)

    Ceballos, G. A.; Hernández, L. F.

    2015-04-01

    Objective. The classical ERP-based speller, or P300 Speller, is one of the most commonly used paradigms in the field of Brain Computer Interfaces (BCI). Several alterations to the visual stimuli presentation system have been developed to avoid unfavorable effects elicited by adjacent stimuli. However, there has been little, if any, regard to useful information contained in responses to adjacent stimuli about spatial location of target symbols. This paper aims to demonstrate that combining the classification of non-target adjacent stimuli with standard classification (target versus non-target) significantly improves classical ERP-based speller efficiency. Approach. Four SWLDA classifiers were trained and combined with the standard classifier: the lower row, upper row, right column and left column classifiers. This new feature extraction procedure and the classification method were carried out on three open databases: the UAM P300 database (Universidad Autonoma Metropolitana, Mexico), BCI competition II (dataset IIb) and BCI competition III (dataset II). Main results. The inclusion of the classification of non-target adjacent stimuli improves target classification in the classical row/column paradigm. A gain in mean single trial classification of 9.6% and an overall improvement of 25% in simulated spelling speed was achieved. Significance. We have provided further evidence that the ERPs produced by adjacent stimuli present discriminable features, which could provide additional information about the spatial location of intended symbols. This work promotes the searching of information on the peripheral stimulation responses to improve the performance of emerging visual ERP-based spellers.

  5. The BOSS: a novel approach to coupling temporal changes in geochemistry and microbiology in the deep subsurface biosphere.

    NASA Astrophysics Data System (ADS)

    Girguis, P. R.; Robidart, J.; Wheat, G.

    2008-12-01

    Though our knowledge of deep subsurface environments is burgeoning, our understanding of the physiological capacity and activity of deep subsurface microbial communities is in its infancy. Specifically, the quantitative relationship between microbial diversity, density, and activity and geochemical cycles is poorly understood, as is true for most marine environments. This is due to the difficulty of concurrently sampling and quantifying both biological and chemical factors over time and space, especially in remote or inhospitable locales. To address this limitation, we have developed a BioOsmoSampling System (or BOSS). Osmosamplers use osmotic pressure to continuously sample seawater, and can be deployed on the order of weeks to years. These osmosamplers have been previously used for geochemical sampling, and we have developed the hardware and reagents to enable their use in microbial sampling. In particular, we have developed the capacity to collect and preserve fluid samples for nucleic acid and protein analyses, as well as lipids and cellular structure (for microscopy). Molecular degradation in a variety of preservatives was <50% (DNA) and <15% (proteins, lipids) after one year, and ongoing efforts suggest that three-year preservation of DNA and proteins is possible. Here we present data from a pilot study, in which we deployed the BOSS at a diffuse flow vent site at the Juan de Fuca Ridge, and an IODP borehole in Middle Valley. We observed co- registered changes in geochemistry (both ions and volatiles), temperature and microbial community composition. We also recovered high densities of previously enigmatic microbes. This proof-of-concept experiment allowed us to correlate changes in microbial population structure with changes in the physicochemical environment in the diffuse hydrothermal flow, and set the stage for future deep subsurface deployments.

  6. The BOSS Emission-line Lens Survey. III. Strong Lensing of Lyα Emitters by Individual Galaxies

    NASA Astrophysics Data System (ADS)

    Shu, Yiping; Bolton, Adam S.; Kochanek, Christopher S.; Oguri, Masamune; Pérez-Fournon, Ismael; Zheng, Zheng; Mao, Shude; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Marques-Chaves, Rui; Ménard, Brice

    2016-06-01

    We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Lyα EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Lyα emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy-LAE candidates selected from ≈ 1.4× {10}6 galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2-3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.

  7. IGM CONSTRAINTS FROM THE SDSS-III/BOSS DR9 Lyα FOREST TRANSMISSION PROBABILITY DISTRIBUTION FUNCTION

    SciTech Connect

    Lee, Khee-Gan; Hennawi, Joseph F.; Spergel, David N.; Weinberg, David H.; Hogg, David W.; Viel, Matteo; Bolton, James S.; Bailey, Stephen; Carithers, William; Schlegel, David J.; Pieri, Matthew M.; Lundgren, Britt; Palanque-Delabrouille, Nathalie; Yèche, Christophe; Schneider, Donald P.

    2015-02-01

    The Lyα forest transmission probability distribution function (PDF) is an established probe of the intergalactic medium (IGM) astrophysics, especially the temperature-density relationship of the IGM. We measure the transmission PDF from 3393 Baryon Oscillations Spectroscopic Survey (BOSS) quasars from Sloan Digital Sky Survey Data Release 9, and compare with mock spectra that include careful modeling of the noise, continuum, and astrophysical uncertainties. The BOSS transmission PDFs, measured at (z) = [2.3, 2.6, 3.0], are compared with PDFs created from mock spectra drawn from a suite of hydrodynamical simulations that sample the IGM temperature-density relationship, γ, and temperature at mean density, T {sub 0}, where T(Δ) = T {sub 0}Δ{sup γ} {sup –} {sup 1}. We find that a significant population of partial Lyman-limit systems (LLSs) with a column-density distribution slope of β{sub pLLS} ∼ – 2 are required to explain the data at the low-transmission end of transmission PDF, while uncertainties in the mean Lyα forest transmission affect the high-transmission end. After modeling the LLSs and marginalizing over mean transmission uncertainties, we find that γ = 1.6 best describes the data over our entire redshift range, although constraints on T {sub 0} are affected by systematic uncertainties. Within our model framework, isothermal or inverted temperature-density relationships (γ ≤ 1) are disfavored at a significance of over 4σ, although this could be somewhat weakened by cosmological and astrophysical uncertainties that we did not model.

  8. Potential bronchoconstrictor stimuli in acid fog.

    PubMed

    Balmes, J R; Fine, J M; Gordon, T; Sheppard, D

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and niric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  9. Potential bronchoconstrictor stimuli in acid fog

    SciTech Connect

    Balmes, J.R.; Fine, J.M.; Gordon, T.; Sheppard, D.

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and nitric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  10. Computer programming for generating visual stimuli.

    PubMed

    Bukhari, Farhan; Kurylo, Daniel D

    2008-02-01

    Critical to vision research is the generation of visual displays with precise control over stimulus metrics. Generating stimuli often requires adapting commercial software or developing specialized software for specific research applications. In order to facilitate this process, we give here an overview that allows nonexpert users to generate and customize stimuli for vision research. We first give a review of relevant hardware and software considerations, to allow the selection of display hardware, operating system, programming language, and graphics packages most appropriate for specific research applications. We then describe the framework of a generic computer program that can be adapted for use with a broad range of experimental applications. Stimuli are generated in the context of trial events, allowing the display of text messages, the monitoring of subject responses and reaction times, and the inclusion of contingency algorithms. This approach allows direct control and management of computer-generated visual stimuli while utilizing the full capabilities of modern hardware and software systems. The flowchart and source code for the stimulus-generating program may be downloaded from www.psychonomic.org/archive.

  11. Categorization of Multidimensional Stimuli by Pigeons

    ERIC Educational Resources Information Center

    Berg, Mark E.; Grace, Randolph C.

    2011-01-01

    Six pigeons responded in a visual category learning task in which the stimuli were dimensionally separable Gabor patches that varied in frequency and orientation. We compared performance in two conditions which varied in terms of whether accurate performance required that responding be controlled jointly by frequency and orientation, or…

  12. Contingent Stimuli Signal Subsequent Reinforcer Ratios

    ERIC Educational Resources Information Center

    Boutros, Nathalie; Davison, Michael; Elliffe, Douglas

    2011-01-01

    Conditioned reinforcer effects may be due to the stimulus' discriminative rather than its strengthening properties. While this was demonstrated in a frequently-changing choice procedure, a single attempt to replicate in a relatively static choice environment failed. We contend that this was because the information provided by the stimuli was…

  13. The temporal primacy of self-related stimuli and negative stimuli: an ERP-based comparative study.

    PubMed

    Zhu, Min; Luo, Junlong; Zhao, Na; Hu, Yinying; Yan, Lingyue; Gao, Xiangping

    2016-10-01

    Numerous studies have shown there exist attention biases for self-related and negative stimuli. Few studies, however, have been carried out to compare the effects of such stimuli on the neural mechanisms of early attentional alertness and subsequent cognitive processing. The purpose of the present study was to examine the temporal primacy of both self-related stimuli and negative stimuli in the neurophysiologic level. In a modified oddball task, event-related potentials of the deviant stimuli (i.e., self-face, negative face and neutral face) were recorded. Results revealed that larger P2 amplitudes were elicited by self-related and negative stimuli than by neutral stimuli. Negative stimuli, however, elicited shorter P2 latencies than self-related and neutral stimuli. As for the N2 component, self-related and negative stimuli elicited smaller amplitudes and shorter latencies than neutral stimuli, but otherwise did not differ. Self-related stimuli also elicited larger P3 and late positive component (LPC) amplitudes than negative and neutral stimuli. The pattern of results suggests that the primacy of negative stimuli occurred at an early attention stage of processing, while the primacy of self-related stimuli occurred at the subsequent cognitive evaluation and memory stage.

  14. Attentional bias towards threatening stimuli in children with anxiety: A meta-analysis.

    PubMed

    Dudeney, Joanne; Sharpe, Louise; Hunt, Caroline

    2015-08-01

    Although it is well known that anxious adults show selective attention to threatening stimuli, research investigating attentional bias in children with anxiety has produced mixed results. The purpose of this paper is to provide a comprehensive analysis of studies investigating attentional bias in children with anxiety. Using a systematic search for articles which included both children with anxiety and reported data suitable for a meta-analysis, 38 articles were identified involving 4221 subjects (anxiety n=2222). We used a random effects meta-analysis with standardized mean difference as our primary outcome to estimate between- and within-group effects of attentional bias towards threat-related information in children with anxiety. Overall, children with anxiety showed a significantly greater bias to threat-related stimuli, compared to controls (d=0.21). Children with anxiety also showed a significant bias to threat-related stimuli, over neutral stimuli (d=0.54), which was greater than the bias shown by control children (d=0.15). Specific variables in attentional bias were also explored, with varying results. The review concluded that anxious children do show a similar bias towards threatening stimuli as has been documented in adults, albeit to a lesser degree and this bias is moderated by age, such that the difference between anxious and control children increases with age. Given the small number of studies in some areas, future research is needed to understand the precise conditions under which anxious children exhibit selective attentional biases to threat-related stimuli.

  15. Photonic water dynamically responsive to external stimuli

    NASA Astrophysics Data System (ADS)

    Sano, Koki; Kim, Youn Soo; Ishida, Yasuhiro; Ebina, Yasuo; Sasaki, Takayoshi; Hikima, Takaaki; Aida, Takuzo

    2016-08-01

    Fluids that contain ordered nanostructures with periodic distances in the visible-wavelength range, anomalously exhibit structural colours that can be rapidly modulated by external stimuli. Indeed, some fish can dynamically change colour by modulating the periodic distance of crystalline guanine sheets cofacially oriented in their fluid cytoplasm. Here we report that a dilute aqueous colloidal dispersion of negatively charged titanate nanosheets exhibits structural colours. In this `photonic water', the nanosheets spontaneously adopt a cofacial geometry with an ultralong periodic distance of up to 675 nm due to a strong electrostatic repulsion. Consequently, the photonic water can even reflect near-infrared light up to 1,750 nm. The structural colour becomes more vivid in a magnetic flux that induces monodomain structural ordering of the colloidal dispersion. The reflective colour of the photonic water can be modulated over the entire visible region in response to appropriate physical or chemical stimuli.

  16. Photonic water dynamically responsive to external stimuli.

    PubMed

    Sano, Koki; Kim, Youn Soo; Ishida, Yasuhiro; Ebina, Yasuo; Sasaki, Takayoshi; Hikima, Takaaki; Aida, Takuzo

    2016-01-01

    Fluids that contain ordered nanostructures with periodic distances in the visible-wavelength range, anomalously exhibit structural colours that can be rapidly modulated by external stimuli. Indeed, some fish can dynamically change colour by modulating the periodic distance of crystalline guanine sheets cofacially oriented in their fluid cytoplasm. Here we report that a dilute aqueous colloidal dispersion of negatively charged titanate nanosheets exhibits structural colours. In this 'photonic water', the nanosheets spontaneously adopt a cofacial geometry with an ultralong periodic distance of up to 675 nm due to a strong electrostatic repulsion. Consequently, the photonic water can even reflect near-infrared light up to 1,750 nm. The structural colour becomes more vivid in a magnetic flux that induces monodomain structural ordering of the colloidal dispersion. The reflective colour of the photonic water can be modulated over the entire visible region in response to appropriate physical or chemical stimuli. PMID:27572806

  17. Blind Braille readers mislocate tactile stimuli.

    PubMed

    Sterr, Annette; Green, Lisa; Elbert, Thomas

    2003-05-01

    In a previous experiment, we observed that blind Braille readers produce errors when asked to identify on which finger of one hand a light tactile stimulus had occurred. With the present study, we aimed to specify the characteristics of this perceptual error in blind and sighted participants. The experiment confirmed that blind Braille readers mislocalised tactile stimuli more often than sighted controls, and that the localisation errors occurred significantly more often at the right reading hand than at the non-reading hand. Most importantly, we discovered that the reading fingers showed the smallest error frequency, but the highest rate of stimulus attribution. The dissociation of perceiving and locating tactile stimuli in the blind suggests altered tactile information processing. Neuroplasticity, changes in tactile attention mechanisms as well as the idea that blind persons may employ different strategies for tactile exploration and object localisation are discussed as possible explanations for the results obtained.

  18. Discrimination of auditory stimuli during isoflurane anesthesia.

    PubMed

    Rojas, Manuel J; Navas, Jinna A; Greene, Stephen A; Rector, David M

    2008-10-01

    Deep isoflurane anesthesia initiates a burst suppression pattern in which high-amplitude bursts are preceded by periods of nearly silent electroencephalogram. The burst suppression ratio (BSR) is the percentage of suppression (silent electroencephalogram) during the burst suppression pattern and is one parameter used to assess anesthesia depth. We investigated cortical burst activity in rats in response to different auditory stimuli presented during the burst suppression state. We noted a rapid appearance of bursts and a significant decrease in the BSR during stimulation. The BSR changes were distinctive for the different stimuli applied, and the BSR decreased significantly more when stimulated with a voice familiar to the rat as compared with an unfamiliar voice. These results show that the cortex can show differential sensory responses during deep isoflurane anesthesia.

  19. Photonic water dynamically responsive to external stimuli

    PubMed Central

    Sano, Koki; Kim, Youn Soo; Ishida, Yasuhiro; Ebina, Yasuo; Sasaki, Takayoshi; Hikima, Takaaki; Aida, Takuzo

    2016-01-01

    Fluids that contain ordered nanostructures with periodic distances in the visible-wavelength range, anomalously exhibit structural colours that can be rapidly modulated by external stimuli. Indeed, some fish can dynamically change colour by modulating the periodic distance of crystalline guanine sheets cofacially oriented in their fluid cytoplasm. Here we report that a dilute aqueous colloidal dispersion of negatively charged titanate nanosheets exhibits structural colours. In this ‘photonic water', the nanosheets spontaneously adopt a cofacial geometry with an ultralong periodic distance of up to 675 nm due to a strong electrostatic repulsion. Consequently, the photonic water can even reflect near-infrared light up to 1,750 nm. The structural colour becomes more vivid in a magnetic flux that induces monodomain structural ordering of the colloidal dispersion. The reflective colour of the photonic water can be modulated over the entire visible region in response to appropriate physical or chemical stimuli. PMID:27572806

  20. Observing of chain-schedule stimuli.

    PubMed

    Slezak, Jonathan M; Anderson, Karen G

    2014-06-01

    A classical-conditioning account of the processes maintaining behavior under chained schedules entails a backward transmission of conditioned-reinforcement effects. Assessing this process in traditional chain schedules is limited because the response maintained by stimulus onset accompanied by each link in a chain schedule may also be maintained by the primary reinforcer. In the present experiment, an observing response was used to measure the conditioned-reinforcing effects of stimuli associated with a three-link chain variable-time (VT) food schedule, and resistance-to-change tests (extinction and prefeeding) were implemented to examine if a backward transmission of reinforcement effects occur. Four pigeons served as subjects. Observing was maintained by the production of stimuli correlated with links of a three-link chain VT schedule with the middle-link stimulus maintaining the highest rate of observing, followed by the initial-link stimulus and the terminal-link stimulus maintaining the lowest observing rate. Results from resistance-to-change tests of extinction and prefeeding were not supportive of a backward transmission of reinforcement effects and in general, the pattern of resistance-to-change was forward. Based on past and current research, it appears that a backward pattern of relative rate decreases in responses maintained by stimuli correlated with a chain schedule due to disruption (i.e., extinction and prefeeding) is not a ubiquitous process that is evident within different chain-schedule arrangements.

  1. Anagrus breviphragma Soyka Short Distance Search Stimuli

    PubMed Central

    Chiappini, Elisabetta; Berzolla, Alessia; Oppo, Annalisa

    2015-01-01

    Anagrus breviphragma Soyka (Hymenoptera: Mymaridae) successfully parasitises eggs of Cicadella viridis (L.) (Homoptera: Cicadellidae), embedded in vegetal tissues, suggesting the idea of possible chemical and physical cues, revealing the eggs presence. In this research, three treatments were considered in order to establish which types of cue are involved: eggs extracted from leaf, used as a control, eggs extracted from leaf and cleaned in water and ethanol, used to evaluate the presence of chemicals soluble in polar solvents, and eggs extracted from leaf and covered with Parafilm (M), used to avoid physical stimuli due to the bump on the leaf surface. The results show that eggs covered with Parafilm present a higher number of parasitised eggs and a lower probing starting time with respect to eggs washed with polar solvents or eggs extracted and untreated, both when the treatments were singly tested or when offered in sequence, independently of the treatment position. These results suggest that the exploited stimuli are not physical due to the bump but chemicals that can spread in the Parafilm, circulating the signal on the whole surface, and that the stimuli that elicit probing and oviposition are not subjected to learning. PMID:26543865

  2. Visual stimuli recruit intrinsically generated cortical ensembles.

    PubMed

    Miller, Jae-eun Kang; Ayzenshtat, Inbal; Carrillo-Reid, Luis; Yuste, Rafael

    2014-09-23

    The cortical microcircuit is built with recurrent excitatory connections, and it has long been suggested that the purpose of this design is to enable intrinsically driven reverberating activity. To understand the dynamics of neocortical intrinsic activity better, we performed two-photon calcium imaging of populations of neurons from the primary visual cortex of awake mice during visual stimulation and spontaneous activity. In both conditions, cortical activity is dominated by coactive groups of neurons, forming ensembles whose activation cannot be explained by the independent firing properties of their contributing neurons, considered in isolation. Moreover, individual neurons flexibly join multiple ensembles, vastly expanding the encoding potential of the circuit. Intriguingly, the same coactive ensembles can repeat spontaneously and in response to visual stimuli, indicating that stimulus-evoked responses arise from activating these intrinsic building blocks. Although the spatial properties of stimulus-driven and spontaneous ensembles are similar, spontaneous ensembles are active at random intervals, whereas visually evoked ensembles are time-locked to stimuli. We conclude that neuronal ensembles, built by the coactivation of flexible groups of neurons, are emergent functional units of cortical activity and propose that visual stimuli recruit intrinsically generated ensembles to represent visual attributes. PMID:25201983

  3. Stimuli-responsive polymersomes for cancer therapy.

    PubMed

    Thambi, Thavasyappan; Park, Jae Hyung; Lee, Doo Sung

    2016-01-01

    Cancer is the leading cause of mortality and remains a major challenge for modern chemotherapy. Recent advances in cancer therapy have made a modest impact on patient survival. Nanomedicine represents an innovative field with significant potential to improve cancer treatment. Nanomedicine utilizes numerous nanoconstructs, including polymersomes, micelles, and drug conjugates, to deliver therapeutic agents at the target site of interest. In particular, polymeric vesicles, also known as polymersomes, are self-assembled amphiphilic polymers in which an aqueous compartment is enclosed by a thick bilayer membrane. Unlike liposomes, polymersomes consist of high-molecular-weight amphiphilic polymer analogues. Since polymersomes are prepared using synthetic amphiphilic polymers, the bilayer membrane thickness can be readily altered by tuning the molecular weight of hydrophobic blocks. As a consequence, the polymersomes prepared from high-molecular-weight amphiphiles strengthen their membranes, making them inherently more stable than liposomes. The intriguing aggregation of polymersomes offers numerous advantages, including stability, tunable membrane properties, and the capability of encapsulating hydrophilic and hydrophobic agents. Owing to these properties, polymersomes are attractive candidates for various applications such as drug delivery, gene therapy, and tissue engineering. Although these properties have placed polymersomes at the forefront of drug delivery applications, to attain an enhanced therapeutic effect polymersomes are supposed to rapidly release the drug at the target site. To fulfill this requirement, stimuli-responsive polymersomes that respond to various internal or external stimuli have been developed. This review focuses on recently developed stimuli-responsive polymersomes and their potential application in cancer therapy.

  4. Spatial Brightness Perception of Trichromatic Stimuli

    SciTech Connect

    Royer, Michael P.; Houser, Kevin W.

    2012-11-16

    An experiment was conducted to examine the effect of tuning optical radiation on brightness perception for younger (18-25 years of age) and older (50 years of age or older) observers. Participants made forced-choice evaluations of the brightness of a full factorial of stimulus pairs selected from two groups of four metameric stimuli. The large-field stimuli were created by systematically varying either the red or the blue primary of an RGB LED mixture. The results indicate that light stimuli of equal illuminance and chromaticity do not appear equally bright to either younger or older subjects. The rank-order of brightness is not predicted by any current model of human vision or theory of brightness perception including Scotopic to Photopic or Cirtopic to Photopic ratio theory, prime color theory, correlated color temperature, V(λ)-based photometry, color quality metrics, linear brightness models, or color appearance models. Age may affect brightness perception when short-wavelength primaries are used, especially those with a peak wavelength shorter than 450 nm. The results suggest further development of metrics to predict brightness perception is warranted, and that including age as a variable in predictive models may be valuable.

  5. Comparison of speciation sampler and PC-BOSS fine particulate matter organic material results obtained in Lindon, Utah, during winter 2001-2002.

    PubMed

    Carter, Cory; Eatough, Norman L; Eatough, Delbert J; Olson, Neal; Long, Russell W

    2008-01-01

    The Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) has been previously verified as being capable of measuring total fine particulate matter (PM2.5), including semi-volatile species. The present study was conducted to determine if the simple modification of a commercial speciation sampler with a charcoal denuder followed by a filter pack containing a quartz filter and a charcoal-impregnated glass (CIG) fiber filter would allow for the measurement of total PM2.5, including semi-volatile organic material. Data were collected using an R&P (Rupprecht and Pastasnik Co., Inc.) Partisol Model 2300 speciation sampler; an R&P Partisol speciation sampler modified with a BOSS denuder, followed by a filter pack with a quartz and a CIG filter; a Met One spiral aerosol speciation sampler (SASS); and the PC-BOSS from November 2001 to March 2002 at a U.S. Environmental Protection Agency (EPA) Science to Achieve Results (STAR) sampling site in Lindon, UT. Total PM2.5 mass, ammonium nitrate (both nonvolatile and semi-volatile), ammonium sulfate, organic carbon (both non-volatile and semi-volatile), and elemental carbon were determined on a 24-hr basis. Results obtained with the individual samplers were compared to determine the capability of the modified R&P speciation sampler for measuring total PM2.5, including semi-volatile components. Data obtained with the modified speciation sampler agreed with the PC-BOSS results. Data obtained with the two unmodified speciation samplers were low by an average of 26% because of the loss of semi-volatile organic material from the quartz filter during sample collection.

  6. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release

    NASA Astrophysics Data System (ADS)

    Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio; Chuang, Chia-Hsun; Zhao, Cheng; Prada, Francisco; Gil-Marín, Héctor; Guo, Hong; Yepes, Gustavo; Klypin, Anatoly; Scóccola, Claudia G.; Tinker, Jeremy; McBride, Cameron; Reid, Beth; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Grieb, Jan Niklas; Vargas-Magana, Mariana; Cuesta, Antonio J.; Neyrinck, Mark; Beutler, Florian; Comparat, Johan; Percival, Will J.; Ross, Ashley

    2016-03-01

    We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillation Spectroscopic Survey Final Data Release (BOSS DR11&DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated (6000) 12 288 MultiDark PATCHY BOSS (DR11) DR12 light cones corresponding to an effective volume of ˜192 000 [h-1 Gpc]3 (the largest ever simulated volume), including cosmic evolution in the redshift range from 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the halo abundance matching modelling of the BOSS DR11&DR12 galaxy clustering data and on the data themselves. The production follows three steps. First, we apply the PATCHY code to generate a dark matter field and an object distribution including non-linear stochastic galaxy bias. Secondly, we run the halo/stellar distribution reconstruction HADRON code to assign masses to the various objects. This step uses the mass distribution as a function of local density and non-local indicators (i.e. tidal field tensor eigenvalues and relative halo exclusion separation for massive objects) from the reference simulation applied to the corresponding patchy dark matter and galaxy distribution. Finally, we apply the SUGAR code to build the light cones. The resulting MultiDarkPATCHY mock light cones reproduce the number density, selection function, survey geometry, and in general within 1σ, for arbitrary stellar mass bins, the power spectrum up to k = 0.3 h Mpc-1, the two-point correlation functions down to a few Mpc scales, and the three-point statistics of the BOSS DR11&DR12 galaxy samples.

  7. Depersonalization Disorder: Disconnection of Cognitive Evaluation from Autonomic Responses to Emotional Stimuli

    PubMed Central

    Michal, Matthias; Koechel, Ansgar; Canterino, Marco; Adler, Julia; Reiner, Iris; Vossel, Gerhard; Beutel, Manfred E.; Gamer, Matthias

    2013-01-01

    Background Patients with depersonalization disorder (DPD) typically complain about emotional detachment. Previous studies found reduced autonomic responsiveness to emotional stimuli for DPD patients as compared to patients with anxiety disorders. We aimed to investigate autonomic responsiveness to emotional auditory stimuli of DPD patients as compared to patient controls. Furthermore, we examined the modulatory effect of mindful breathing on these responses as well as on depersonalization intensity. Methods 22 DPD patients and 15 patient controls balanced for severity of depression and anxiety, age, sex and education, were compared regarding 1) electrodermal and heart rate data during a resting period, and 2) autonomic responses and cognitive appraisal of standardized acoustic affective stimuli in two conditions (normal listening and mindful breathing). Results DPD patients rated the emotional sounds as significantly more neutral as compared to patient controls and standardized norm ratings. At the same time, however, they responded more strongly to acoustic emotional stimuli and their electrodermal response pattern was more modulated by valence and arousal as compared to patient controls. Mindful breathing reduced severity of depersonalization in DPD patients and increased the arousal modulation of electrodermal responses in the whole sample. Finally, DPD patients showed an increased electrodermal lability in the rest period as compared to patient controls. Conclusions These findings demonstrated that the cognitive evaluation of emotional sounds in DPD patients is disconnected from their autonomic responses to those emotional stimuli. The increased electrodermal lability in DPD may reflect increased introversion and cognitive control of emotional impulses. The findings have important psychotherapeutic implications. PMID:24058547

  8. The Facilitative Effect of Positive Stimuli on 3-Year-Olds' Flexible Rule Use

    ERIC Educational Resources Information Center

    Qu, Li; Zelazo, Philip David

    2007-01-01

    This study examined the effect of emotional stimuli on 3- to 4-year old children's flexible rule use, as measured by the Dimensional Change Card Sort (DCCS). In Experiment 1, children in two countries (Canada and China) were given 2 versions of the DCCS. The Standard version required children to sort red and blue boats and rabbits first by shape…

  9. Advances in stimuli responsive nanobiomaterials for cancer therapy.

    PubMed

    Sampathkumar, Kaarunya; Arulkumar, Shylaja; Ramalingam, Murugan

    2014-03-01

    Cancer has become one of the major reasons for disease mortality with drastic increase of death rate in recent years. The reason for most of these deaths is due to the inefficacy and failure of the current methods of treatments or due to the unavailability of treatment options. Even after extensive research that has been carried out in the field, there is no gold standard in cancer therapy. With the advancement of the field of nanomedicine and materials science, many research works are being aimed at developing micro and nanocarriers for site-specific delivery of anticancer drugs. As a further advancement in the field, smart carriers, based on nanobiomaterials, which respond to various external and internal stimuli and act locally are being developed to improve the efficacy of current treatments. These smart nanobiomaterials act as carriers for not only anticancer drugs but also for gene and other biomolecules. Keeping the importance and advancement of smart carrier anticancer drug delivery system (AcDDS) in view, this review focuses on stimuli responsive nanobiomaterials that are currently being studied for cancer therapy. PMID:24730233

  10. Dorsal horn spatial representation of simple cutaneous stimuli.

    PubMed

    Brown, P B; Millecchia, R; Lawson, J J; Stephens, S; Harton, P; Culberson, J C

    1998-02-01

    A model of lamina III-IV dorsal horn cell receptive fields (RFs) has been developed to visualize the spatial patterns of cells activated by light touch stimuli. Low-threshold mechanoreceptive fields (RFs) of 551 dorsal horn neurons recorded in anesthetized cats were characterized by location of RF center in cylindrical coordinates, area, length/width ratio, and orientation of long axis. Best-fitting ellipses overlapped actual RFs by 90%. Exponentially smoothed mean and variance surfaces were estimated for these five variables, on a grid of 40 points mediolaterally by 20/segment rostrocaudally in dorsal horn segments L4-S1. The variations of model RF location, area, and length/width ratio with map location were all similar to previous observations. When elliptical RFs were simulated at the locations of the original cells, the RFs of real and simulated cells overlapped by 64%. The densities of cell representations of skin points on the hindlimb were represented as pseudocolor contour plots on dorsal view maps, and segmental representations were plotted on the standard views of the leg. Overlap of modeled and real segmental representations was at the 84% level. Simulated and observed RFs had similar relations between area and length/width ratio and location on the hindlimb: r(A) = 0.52; r(L/W) = 0.56. Although the representation of simple stimuli was orderly, and there was clearly only one somatotopic map of the skin, the representation of a single point often was not a single cluster of active neurons. When two-point stimuli were simulated, there usually was no fractionation of response zones or addition of new zones. Variation of stimulus size (area of skin contacted) produced less variation of representation size (number of cells responding) than movement of stimuli from one location to another. We conclude that stimulus features are preserved poorly in their dorsal horn spatial representation and that discrimination mechanisms that depend on detection of such

  11. Wind turbine acoustic standards

    NASA Technical Reports Server (NTRS)

    Stephens, D. G.; Shepherd, K. P.; Grosveld, F.

    1981-01-01

    A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described.

  12. Children's Preference for Stimuli Associated with Being Imitated.

    ERIC Educational Resources Information Center

    Parton, David A.; Priefert, Maria J.

    Forty-eight preschool children were run under a classical conditioning paradigm in which some neutral stimuli were repeatedly associated with an adult matching the behavior of the subject, and other neutral stimuli were associated with the same adult mismatching the behavior of the subject. Preference for the stimuli associated with being matched…

  13. Developmental Changes in Infant Attention to Dynamic and Static Stimuli

    ERIC Educational Resources Information Center

    Shaddy, D. Jill; Colombo, John

    2004-01-01

    This study examined 4- and 6-month-olds' responses to static or dynamic stimuli using behavioral and heart-rate-defined measures of attention. Infants looked longest to dynamic stimuli with an audio track and least to a static stimulus that was mute. Overall, look duration declined with age to the different stimuli. The amount of time spent in…

  14. Olfactory Stimuli Increase Presence in Virtual Environments

    PubMed Central

    Munyan, Benson G.; Neer, Sandra M.; Beidel, Deborah C.; Jentsch, Florian

    2016-01-01

    Background Exposure therapy (EXP) is the most empirically supported treatment for anxiety and trauma-related disorders. EXP consists of repeated exposure to a feared object or situation in the absence of the feared outcome in order to extinguish associated anxiety. Key to the success of EXP is the need to present the feared object/event/situation in as much detail and utilizing as many sensory modalities as possible, in order to augment the sense of presence during exposure sessions. Various technologies used to augment the exposure therapy process by presenting multi-sensory cues (e.g., sights, smells, sounds). Studies have shown that scents can elicit emotionally charged memories, but no prior research has examined the effect of olfactory stimuli upon the patient’s sense of presence during simulated exposure tasks. Methods 60 adult participants navigated a mildly anxiety-producing virtual environment (VE) similar to those used in the treatment of anxiety disorders. Participants had no autobiographical memory associated with the VE. State anxiety, Presence ratings, and electrodermal (EDA) activity were collected throughout the experiment. Results Utilizing a Bonferroni corrected Linear Mixed Model, our results showed statistically significant relationships between olfactory stimuli and presence as assessed by both the Igroup Presence Questionnaire (IPQ: R2 = 0.85, (F(3,52) = 6.625, p = 0.0007) and a single item visual-analogue scale (R2 = 0.85, (F(3,52) = 5.382, p = 0.0027). State anxiety was unaffected by the presence or absence of olfactory cues. EDA was unaffected by experimental condition. Conclusion Olfactory stimuli increase presence in virtual environments that approximate those typical in exposure therapy, but did not increase EDA. Additionally, once administered, the removal of scents resulted in a disproportionate decrease in presence. Implications for incorporating the use of scents to increase the efficacy of exposure therapy is discussed. PMID

  15. An online brain-computer interface based on shifting attention to concurrent streams of auditory stimuli

    NASA Astrophysics Data System (ADS)

    Hill, N. J.; Schölkopf, B.

    2012-04-01

    We report on the development and online testing of an electroencephalogram-based brain-computer interface (BCI) that aims to be usable by completely paralysed users—for whom visual or motor-system-based BCIs may not be suitable, and among whom reports of successful BCI use have so far been very rare. The current approach exploits covert shifts of attention to auditory stimuli in a dichotic-listening stimulus design. To compare the efficacy of event-related potentials (ERPs) and steady-state auditory evoked potentials (SSAEPs), the stimuli were designed such that they elicited both ERPs and SSAEPs simultaneously. Trial-by-trial feedback was provided online, based on subjects' modulation of N1 and P3 ERP components measured during single 5 s stimulation intervals. All 13 healthy subjects were able to use the BCI, with performance in a binary left/right choice task ranging from 75% to 96% correct across subjects (mean 85%). BCI classification was based on the contrast between stimuli in the attended stream and stimuli in the unattended stream, making use of every stimulus, rather than contrasting frequent standard and rare ‘oddball’ stimuli. SSAEPs were assessed offline: for all subjects, spectral components at the two exactly known modulation frequencies allowed discrimination of pre-stimulus from stimulus intervals, and of left-only stimuli from right-only stimuli when one side of the dichotic stimulus pair was muted. However, attention modulation of SSAEPs was not sufficient for single-trial BCI communication, even when the subject's attention was clearly focused well enough to allow classification of the same trials via ERPs. ERPs clearly provided a superior basis for BCI. The ERP results are a promising step towards the development of a simple-to-use, reliable yes/no communication system for users in the most severely paralysed states, as well as potential attention-monitoring and -training applications outside the context of assistive technology.

  16. Attentional orienting towards smoking-related stimuli.

    PubMed

    Hogarth, L C; Mogg, K; Bradley, B P; Duka, T; Dickinson, A

    2003-03-01

    According to incentive salience theory, conditioned stimuli (CS+) associated with drug reinforcement acquire the capacity to elicit a conditioned attentional orienting response, which controls drug-seeking and drug-taking behaviour. We sought evidence for this proposal by measuring visual attentional orienting towards smoking pictures presented briefly in the periphery of the visual field, versus control pictures likewise presented, in smokers versus non-smokers. In each trial, smokers and non-smokers responded manually to a dot probe stimulus that appeared in a location previously occupied by either a smoking picture or a control picture. Attentional bias scores were calculated by subtracting the median reaction time (RT) in the former condition from the median RT in the latter condition. In two experiments, light-smokers (smokers of fewer than 20 cigarettes/day) produced a mean bias score that was significantly greater than that of heavy-smokers (smokers of 20 or more cigarettes/day) and non-smokers. In addition, when smokers from the two experiments were pooled, a significant quadratic relationship was found between cigarettes/day and the attentional bias for the smoking stimuli. These findings are consistent with incentive salience theories and dual-process theories of addiction.

  17. Stimuli-Responsive Nanomaterials for Biomedical Applications

    PubMed Central

    2015-01-01

    Nature employs a variety of tactics to precisely time and execute the processes and mechanics of life, relying on sequential sense and response cascades to transduce signaling events over multiple length and time scales. Many of these tactics, such as the activation of a zymogen, involve the direct manipulation of a material by a stimulus. Similarly, effective therapeutics and diagnostics require the selective and efficient homing of material to specific tissues and biomolecular targets with appropriate temporal resolution. These systems must also avoid undesirable or toxic side effects and evade unwanted removal by endogenous clearing mechanisms. Nanoscale delivery vehicles have been developed to package materials with the hope of delivering them to select locations with rates of accumulation and clearance governed by an interplay between the carrier and its cargo. Many modern approaches to drug delivery have taken inspiration from natural activatable materials like zymogens, membrane proteins, and metabolites, whereby stimuli initiate transformations that are required for cargo release, prodrug activation, or selective transport. This Perspective describes key advances in the field of stimuli-responsive nanomaterials while highlighting some of the many challenges faced and opportunities for development. Major hurdles include the increasing need for powerful new tools and strategies for characterizing the dynamics, morphology, and behavior of advanced delivery systems in situ and the perennial problem of identifying truly specific and useful physical or molecular biomarkers that allow a material to autonomously distinguish diseased from normal tissue. PMID:25474531

  18. Dynamic stimuli: accentuating aesthetic preference biases.

    PubMed

    Friedrich, Trista E; Harms, Victoria L; Elias, Lorin J

    2014-01-01

    Despite humans' preference for symmetry, artwork often portrays asymmetrical characteristics that influence the viewer's aesthetic preference for the image. When presented with asymmetrical images, aesthetic preference is often given to images whose content flows from left-to-right and whose mass is located on the right of the image. Cerebral lateralization has been suggested to account for the left-to-right directionality bias; however, the influence of cultural factors, such as scanning habits, on aesthetic preference biases is debated. The current research investigates aesthetic preference for mobile objects and landscapes, as previous research has found contrasting preference for the two image types. Additionally, the current experiment examines the effects of dynamic movement on directionality preference to test the assumption that static images are perceived as aesthetically equivalent to dynamic images. After viewing mirror-imaged pairs of pictures and videos, right-to-left readers failed to show a preference bias, whereas left-to-right readers preferred stimuli with left-to-right directionality regardless of the location of the mass. The directionality bias in both reading groups was accentuated by the videos, but the bias was significantly stronger in left-to-right readers. The findings suggest that scanning habits moderate the leftward bias resulting from hemispheric specialization and that dynamic stimuli further fluent visual processing.

  19. Exploring strategies for classification of external stimuli using statistical features of the plant electrical response.

    PubMed

    Chatterjee, Shre Kumar; Das, Saptarshi; Maharatna, Koushik; Masi, Elisa; Santopolo, Luisa; Mancuso, Stefano; Vitaletti, Andrea

    2015-03-01

    Plants sense their environment by producing electrical signals which in essence represent changes in underlying physiological processes. These electrical signals, when monitored, show both stochastic and deterministic dynamics. In this paper, we compute 11 statistical features from the raw non-stationary plant electrical signal time series to classify the stimulus applied (causing the electrical signal). By using different discriminant analysis-based classification techniques, we successfully establish that there is enough information in the raw electrical signal to classify the stimuli. In the process, we also propose two standard features which consistently give good classification results for three types of stimuli--sodium chloride (NaCl), sulfuric acid (H₂SO₄) and ozone (O₃). This may facilitate reduction in the complexity involved in computing all the features for online classification of similar external stimuli in future.

  20. ANSI/AIAA S-081A, Pressure Vessel Standards Implementation Guidelines

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael J.

    2009-01-01

    The stress rupture specification for Composite Overwrapped Pressure Vessels (COPV) is discussed. The composite shell of the COPV shall be designed to meet the design life considering the time it is under sustained load. A Mechcanical Damage Control Plan (MDCP) shall be created and implemented that assures the COPV will not fail due to mechanical damage due to manufacturing, testing, shipping, installation, or flight. Proven processes and procedures for fabrication and repair shall be used to preclude damage or material degradation during material processing, manufacturing operations, and refurbushment.Selected NDI techniques for the liner and/or boss(es) shall be performed before overwrapping with composite. When visual inspection reveals mechanical damage or defects exceeding manufacturing specification levels (and standard repair procedures), the damaged COPV shall be submitted to a material review board (MRB) for disposition. Every COPV shall be subjected to visual and other non-destructive inspection (NDI), per the inspection plan.

  1. Influence of different mechanical stimuli in a multi-scale mechanobiological isotropic model for bone remodelling.

    PubMed

    Mercuri, E G F; Daniel, A L; Hecke, M B; Carvalho, L

    2016-09-01

    This work represents a study of a mathematical model that describes the biological response to different mechanical stimuli in a cellular dynamics model for bone remodelling. The biological system discussed herein consists of three specialised cellular types, responsive osteoblasts, active osteoblasts and osteoclasts, three types of signalling molecules, transforming growth factor beta (TGF-β), receptor activator of nuclear factor kappa-b ligand (RANKL) and osteoprotegerin (OPG) and the parathyroid hormone (PTH). Three proposals for mechanical stimuli were tested: strain energy density (SED), hydrostatic and deviatoric parts of SED. The model was tested in a two-dimensional geometry of a standard human femur. The spatial discretization was performed by the finite element method while the temporal evolution of the variables was calculated by the 4th order Runge-Kutta method. The obtained results represent the temporal evolution of the apparent density distribution and the mean apparent density and thickness for the cortical bone after 600 days of remodelling simulation. The main contributions of this paper are the coupling of mechanical and biological models and the exploration of how the different mechanical stimuli affect the cellular activity in different types of physical activities. The results revealed that hydrostatic SED stimulus was able to form more cortical bone than deviatoric SED and total SED stimuli. The computational model confirms how different mechanical stimuli can impact in the balance of bone homeostasis.

  2. Stimuli dependent impedance of conductive magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Xuan, Shouhu; Dong, Bo; Xu, Feng; Gong, Xinglong

    2016-02-01

    The structure dependent impedance of conductive magnetorheological elastomers (MREs) under different loads and magnetic fields has been studied in this work. By increasing the weight fraction of iron particles, the conductivity of the MREs increased. Dynamic mechanical measurements and synchrotron radiation x-ray computed tomography (SR-CT) were used and they provided reasons for the electrical properties changing significantly under pressure and magnetic field stimulation. The high sensitivity of MREs to external stimuli renders them suitable for application in force or magnetic field sensors. The equivalent circuit model was proposed to analyze the impedance response of MREs and it fits the experimental results very well. Each circuit component reflected the change of the inner interface under different conditions, thus relative changes in the microstructure could be distinguished. This method could be used not only to detect the structural changes in the MRE but also to provide a great deal of valuable information for the further understanding of the MR mechanism.

  3. Termination of pinned spirals by local stimuli

    NASA Astrophysics Data System (ADS)

    Chen, Jiang-Xing; Guo, Ming-Ming; Ma, Jun

    2016-02-01

    The termination of pinned spirals on a defect by means of local stimuli is studied. On a completely unexcitable defect, the elimination process is discussed and its corresponding mechanism is presented. Especially, the mechanism of unpinning spirals on a partially unexcitable defect, which has not been investigated so far, is explored. With fixed pacing frequency ω L , there exists a maximal radius R max above which the pinned spiral cannot be removed. It is found that the value of R max does not increase as ω L in a dynamical regime, forming a platform in the R\\textit{max}\\text-ωL curves. Based on analyzing the dispersion relation on the spiral tip around the obstacle, the underlying mechanism is clarified. Also, it is found that when multiple spirals are pinned, the value of R max decreases on a partially unexcitable defect while the change is very slight on a completely unexcitable one.

  4. Working memory of emotional stimuli: Electrophysiological characterization.

    PubMed

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory.

  5. MULTIFUNCTIONAL AND STIMULI-SENSITIVE PHARMACEUTICAL NANOCARRIERS

    PubMed Central

    Torchilin, Vladimir

    2011-01-01

    Currently used pharmaceutical nanocarriers, such as liposomes, micelles, and polymeric nanoparticles, demonstrate a broad variety of useful properties, such as longevity in the body; specific targeting to certain disease sites; enhanced intracellular penetration; contrast properties allowing for direct carrier visualization in vivo; stimili-sensitivity, and others. Some of those pharmaceutical carriers have already made their way into clinic, while others are still under preclinical development. In certain cases, the pharmaceutical nanocarriers combine several of the listed properties. Long-circulating immunoliposomes capable of prolonged residence in the blood and specific target recognition represent one of examples of this kind. The engineering of multifunctional pharmaceutical nanocarriers combining several useful properties in one particle can significantly enhance the efficacy of many therapeutic and diagnostic protocols. This paper considers the current status and possible future directions in the emerging area of multifunctional nanocarriers with primary attention on the combination of such properties as longevity, targetability, intracellular penetration, contrast loading, and stimuli sensitivity. PMID:18977297

  6. Stimuli-sensitive intrinsically disordered protein brushes

    NASA Astrophysics Data System (ADS)

    Srinivasan, Nithya; Bhagawati, Maniraj; Ananthanarayanan, Badriprasad; Kumar, Sanjay

    2014-10-01

    Grafting polymers onto surfaces at high density to yield polymer brush coatings is a widely employed strategy to reduce biofouling and interfacial friction. These brushes almost universally feature synthetic polymers, which are often heterogeneous and do not readily allow incorporation of chemical functionalities at precise sites along the constituent chains. To complement these synthetic systems, we introduce a biomimetic, recombinant intrinsically disordered protein that can assemble into an environment-sensitive brush. This macromolecule adopts an extended conformation and can be grafted to solid supports to form oriented protein brushes that swell and collapse dramatically with changes in solution pH and ionic strength. We illustrate the value of sequence specificity by using proteases with mutually orthogonal recognition sites to modulate brush height in situ to predictable values. This study demonstrates that stimuli-responsive brushes can be fabricated from proteins and introduces them as a new class of smart biomaterial building blocks.

  7. Stimuli-Responsive Materials for Controlled Release of Theranostic Agents

    PubMed Central

    Wang, Yucai; Shim, Min Suk; Levinson, Nathanael S.; Sung, Hsing-Wen

    2014-01-01

    Stimuli-responsive materials are so named because they can alter their physicochemical properties and/or structural conformations in response to specific stimuli. The stimuli can be internal, such as physiological or pathological variations in the target cells/tissues, or external, such as optical and ultrasound radiations. In recent years, these materials have gained increasing interest in biomedical applications due to their potential for spatially and temporally controlled release of theranostic agents in response to the specific stimuli. This article highlights several recent advances in the development of such materials, with a focus on their molecular designs and formulations. The future of stimuli-responsive materials will also be explored, including combination with molecular imaging probes and targeting moieties, which could enable simultaneous diagnosis and treatment of a specific disease, as well as multi-functionality and responsiveness to multiple stimuli, all important in overcoming intrinsic biological barriers and increasing clinical viability. PMID:25477774

  8. Gating of attention towards food stimuli in binge eating disorder.

    PubMed

    Schmitz, Florian; Naumann, Eva; Biehl, Stefanie; Svaldi, Jennifer

    2015-12-01

    Cognitive models of eating disorders propose that attentional biases for disorder-relevant stimuli contribute to eating disorder pathology. Empirical evidence of a contribution of attentional biases for binge eating disorder (BED) is still scarce. The aim of the present study was to assess attention engagement towards, and disengagement from, food stimuli in overweight females with BED (n = 25) and a group of overweight and obese women without BED (OW; n = 30). Participants completed a rapid serial visual presentation (RSVP) paradigm with food and neutral words as target stimuli. This task can be used to decompose an attentional bias for food stimuli into its stimulus engagement and stimulus disengagement components. Findings indicate that facilitated stimulus engagement for food stimuli over neutral stimuli was more pronounced in the BED group compared to the OW group. Conversely, there were no substantial disengagement effects in either group. Thereby, results support the idea that early attentional processes are biased in BED.

  9. Gating of attention towards food stimuli in binge eating disorder.

    PubMed

    Schmitz, Florian; Naumann, Eva; Biehl, Stefanie; Svaldi, Jennifer

    2015-12-01

    Cognitive models of eating disorders propose that attentional biases for disorder-relevant stimuli contribute to eating disorder pathology. Empirical evidence of a contribution of attentional biases for binge eating disorder (BED) is still scarce. The aim of the present study was to assess attention engagement towards, and disengagement from, food stimuli in overweight females with BED (n = 25) and a group of overweight and obese women without BED (OW; n = 30). Participants completed a rapid serial visual presentation (RSVP) paradigm with food and neutral words as target stimuli. This task can be used to decompose an attentional bias for food stimuli into its stimulus engagement and stimulus disengagement components. Findings indicate that facilitated stimulus engagement for food stimuli over neutral stimuli was more pronounced in the BED group compared to the OW group. Conversely, there were no substantial disengagement effects in either group. Thereby, results support the idea that early attentional processes are biased in BED. PMID:26212270

  10. Invisible visual stimuli elicit increases in alpha-band power.

    PubMed

    Bareither, Isabelle; Chaumon, Maximilien; Bernasconi, Fosco; Villringer, Arno; Busch, Niko A

    2014-09-01

    The cerebral cortex responds to stimuli of a wide range of intensities. Previous studies have demonstrated that undetectably weak somatosensory stimuli cause a functional deactivation or inhibition in somatosensory cortex. In the present study, we tested whether invisible visual stimuli lead to similar responses, indicated by an increase in EEG alpha-band power-an index of cortical excitability. We presented subliminal and supraliminal visual stimuli after estimating each participant's detection threshold. Stimuli consisted of peripherally presented small circular patches that differed in their contrast to a background consisting of a random white noise pattern. We demonstrate that subliminal and supraliminal stimuli each elicit specific neuronal response patterns. Supraliminal stimuli evoked an early, strongly phase-locked lower-frequency response representing the evoked potential and induced a decrease in alpha-band power from 400 ms on. By contrast, subliminal visual stimuli induced an increase of non-phase-locked power around 300 ms that was maximal within the alpha-band. This response might be due to an inhibitory mechanism, which reduces spurious visual activation that is unlikely to result from external stimuli. PMID:24872526

  11. Multi-Stimuli Responsive Macromolecules and Their Assemblies

    PubMed Central

    Zhuang, Jiaming; Gordon, Mallory; Ventura, Judy; Li, Longyu; Thayumanavan, S.

    2013-01-01

    In this review, we outline examples that illustrate the design criteria for achieving macromolecular assemblies that incorporate a combination of two or more chemical, physical or biological stimuli-responsive components. Progress in both fundamental investigation into the phase transformations of these polymers in response to multiple stimuli and their utilization in a variety of pratical applications have been highlighted. Using these examples, we aim to explain the origin of employed mechanisms of stimuli responsiveness which may serve as a guideline to inspire future design of multi-stimuli responsive materials. PMID:23765263

  12. Invisible visual stimuli elicit increases in alpha-band power.

    PubMed

    Bareither, Isabelle; Chaumon, Maximilien; Bernasconi, Fosco; Villringer, Arno; Busch, Niko A

    2014-09-01

    The cerebral cortex responds to stimuli of a wide range of intensities. Previous studies have demonstrated that undetectably weak somatosensory stimuli cause a functional deactivation or inhibition in somatosensory cortex. In the present study, we tested whether invisible visual stimuli lead to similar responses, indicated by an increase in EEG alpha-band power-an index of cortical excitability. We presented subliminal and supraliminal visual stimuli after estimating each participant's detection threshold. Stimuli consisted of peripherally presented small circular patches that differed in their contrast to a background consisting of a random white noise pattern. We demonstrate that subliminal and supraliminal stimuli each elicit specific neuronal response patterns. Supraliminal stimuli evoked an early, strongly phase-locked lower-frequency response representing the evoked potential and induced a decrease in alpha-band power from 400 ms on. By contrast, subliminal visual stimuli induced an increase of non-phase-locked power around 300 ms that was maximal within the alpha-band. This response might be due to an inhibitory mechanism, which reduces spurious visual activation that is unlikely to result from external stimuli.

  13. Predator and heterospecific stimuli alter behaviour in cattle.

    PubMed

    Kluever, Bryan M; Howery, Larry D; Breck, Stewart W; Bergman, David L

    2009-05-01

    Wild and domestic ungulates modify their behaviour in the presence of olfactory and visual cues of predators but investigations have not exposed a domestic species to a series of cues representing various predators and other ungulate herbivores. We used wolf (Canis lupus), mountain lion (Puma concolor), and mule deer (Odocoileus hemionus) stimuli (olfactory and visual), and a control (no stimuli) to experimentally test for differences in behaviour of cattle (Bos taurus) raised in Arizona. We measured (1) vigilance, (2) foraging rates, (3) giving up density (GUD) of high quality foods and (4) time spent in high quality forage locations in response to location of stimuli treatments. In general, we found a consistent pattern in that wolf and deer treatments caused disparate results in all 4 response variables. Wolf stimuli significantly increased cattle vigilance and decreased cattle foraging rates; conversely, deer stimuli significantly increased cattle foraging rate and increased cattle use of high quality forage areas containing stimuli. Mountain lion stimuli did not significantly impact any of the 4 response variables. Our findings suggest that domestic herbivores react to predatory stimuli, can differentiate between stimuli representing two predatory species, and suggest that cattle may reduce antipredatory behaviour when near heterospecifics. PMID:19429201

  14. The power spectrum and bispectrum of SDSS DR11 BOSS galaxies - II. Cosmological interpretation

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Verde, Licia; Noreña, Jorge; Cuesta, Antonio J.; Samushia, Lado; Percival, Will J.; Wagner, Christian; Manera, Marc; Schneider, Donald P.

    2015-09-01

    We examine the cosmological implications of the measurements of the linear growth rate of cosmological structure obtained in a companion paper from the power spectrum and bispectrum monopoles of the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey Data Release 11, CMASS galaxies. This measurement was of f 0.43σ8, where σ8 is the amplitude of dark matter density fluctuations, and f is the linear growth rate, at the effective redshift of the survey, zeff = 0.57. In conjunction with cosmic microwave background (CMB) data, interesting constraints can be placed on models with non-standard neutrino properties and models where gravity deviates from General Relativity on cosmological scales. In particular, the sum of the masses of the three species of the neutrinos is constrained to mν < 0.49 eV (at 95 per cent confidence level) when the f 0.43σ8 measurement is combined with state-of-the-art CMB measurements. Allowing the effective number of neutrinos to vary as a free parameter does not significantly change these results. When we combine the measurement of f 0.43σ8 with the complementary measurement of fσ8 from the monopole and quadrupole of the two-point correlation function, we are able to obtain an independent measurements of f and σ8. We obtain f = 0.63 ± 0.16 and σ8 = 0.710 ± 0.086 (68 per cent confidence level). This is the first time when these parameters have been able to be measured independently using the redshift-space power spectrum and bispectrum measurements from galaxy clustering data only.

  15. Stereotypic vision: how stereotypes disambiguate visual stimuli.

    PubMed

    Correll, Joshua; Wittenbrink, Bernd; Crawford, Matthew T; Sadler, Melody S

    2015-02-01

    Three studies examined how participants use race to disambiguate visual stimuli. Participants performed a first-person-shooter task in which Black and White targets appeared holding either a gun or an innocuous object (e.g., a wallet). In Study 1, diffusion analysis (Ratcliff, 1978) showed that participants rapidly acquired information about a gun when it appeared in the hands of a Black target, and about an innocuous object in the hands of a White target. For counterstereotypic pairings (armed Whites, unarmed Blacks), participants acquired information more slowly. In Study 2, eye tracking showed that participants relied on more ambiguous information (measured by visual angle from fovea) when responding to stereotypic targets; for counterstereotypic targets, they achieved greater clarity before responding. In Study 3, participants were briefly exposed to targets (limiting access to visual information) but had unlimited time to respond. In spite of their slow, deliberative responses, they showed racial bias. This pattern is inconsistent with control failure and suggests that stereotypes influenced identification of the object. All 3 studies show that race affects visual processing by supplementing objective information. PMID:25603373

  16. Anchoring in Numeric Judgments of Visual Stimuli

    PubMed Central

    Langeborg, Linda; Eriksson, Mårten

    2016-01-01

    This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious. PMID:26941684

  17. Anchoring in Numeric Judgments of Visual Stimuli.

    PubMed

    Langeborg, Linda; Eriksson, Mårten

    2016-01-01

    This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious. PMID:26941684

  18. Anchoring in Numeric Judgments of Visual Stimuli.

    PubMed

    Langeborg, Linda; Eriksson, Mårten

    2016-01-01

    This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious.

  19. Stereotypic vision: how stereotypes disambiguate visual stimuli.

    PubMed

    Correll, Joshua; Wittenbrink, Bernd; Crawford, Matthew T; Sadler, Melody S

    2015-02-01

    Three studies examined how participants use race to disambiguate visual stimuli. Participants performed a first-person-shooter task in which Black and White targets appeared holding either a gun or an innocuous object (e.g., a wallet). In Study 1, diffusion analysis (Ratcliff, 1978) showed that participants rapidly acquired information about a gun when it appeared in the hands of a Black target, and about an innocuous object in the hands of a White target. For counterstereotypic pairings (armed Whites, unarmed Blacks), participants acquired information more slowly. In Study 2, eye tracking showed that participants relied on more ambiguous information (measured by visual angle from fovea) when responding to stereotypic targets; for counterstereotypic targets, they achieved greater clarity before responding. In Study 3, participants were briefly exposed to targets (limiting access to visual information) but had unlimited time to respond. In spite of their slow, deliberative responses, they showed racial bias. This pattern is inconsistent with control failure and suggests that stereotypes influenced identification of the object. All 3 studies show that race affects visual processing by supplementing objective information.

  20. Processing of Voiced and Unvoiced Acoustic Stimuli in Musicians

    PubMed Central

    Ott, Cyrill Guy Martin; Langer, Nicolas; Oechslin, Mathias S.; Meyer, Martin; Jäncke, Lutz

    2011-01-01

    Past research has shown that musical training induces changes in the processing of supra-segmental aspects of speech, such as pitch and prosody. The aim of the present study was to determine whether musical expertise also leads to an altered neurophysiological processing of sub-segmental information available in the speech signal, in particular the voice-onset-time. Using high-density EEG-recordings we analyzed the neurophysiological responses to voiced and unvoiced consonant-vowel-syllables and noise-analogs in 26 German speaking adult musicians and non-musicians. From the EEG the N1 amplitude of the event-related potential and two microstates from the topographical EEG analysis (one around the N1 amplitude and one immediately preceding the N1 microstate) were calculated to the different stimuli. Similar to earlier studies the N1 amplitude was different to voiced and unvoiced stimuli in non-musicians with larger amplitudes to voiced stimuli. The more refined microstate analysis revealed that the microstate within the N1 time window was shorter to unvoiced stimuli in non-musicians. For musicians there was no difference for the N1 amplitudes and the corresponding microstates between voiced and unvoiced stimuli. In addition, there was a longer very early microstate preceding the microstate at the N1 time window to non-speech stimuli only in musicians. Taken together, our findings suggest that musicians process unvoiced stimuli (irrespective whether these stimuli are speech or non-speech stimuli) differently than controls. We propose that musicians utilize the same network to analyze unvoiced stimuli as for the analysis of voiced stimuli. As a further explanation it is also possible that musicians devote more neurophysiological resources into the analysis of unvoiced segments. PMID:21922011

  1. Comparison of the mineralogy of the Boss-Bixby, Missouri copper-iron deposit, and the Olympic Dam copper-uranium-gold deposit, South Australia

    SciTech Connect

    Brandom, R.T.; Hagni, R.D.; Allen, C.R.

    1985-01-01

    An ore microscopic examination of 80 polished sections prepared from selected drill core specimens from the Boss-Bixby, Missouri copper-iron deposit has shown that its mineral assemblage is similar to that of the Olympic Dam (Roxby Downs) copper-uranium-gold deposit in South Australia. A comparison with the mineralogy reported for Olympic Dam shows that both deposits contain: 1) the principal minerals, magnetite, hematite, chalcopyrite, and bornite, 2) the cobalt-bearing phases, carrollite and cobaltian pyrite, 3) the titanium oxides, rutile and anatase, 4) smaller amounts of martite, covellite, and electrum, 5) fluorite and carbonates, and 6) some alteration minerals. The deposits also are similar with regard to the sequence of mineral deposition: 1) early oxides, 2) then sulfide minerals, and 3) a final oxide generation. The deposits, however, are dissimilar with regard to their host rock lithologies and structural settings. The Boss-Bixby ores occupy breccia zones within a hydrothermally altered basic intrusive and intruded silicic volcanics, whereas the Olympic Dam ores are contained in sedimentary breccias in a graben or trough. Also, some minerals have been found thus far to occur at only one of the deposits. The similarity of mineralogy in these deposits suggests that they were formed from ore fluids that had some similarities in character and that the St. Francois terrane of Missouri is an important region for further exploration for deposits with this mineral assemblage.

  2. 'Ecstasy' as a social drug: MDMA preferentially affects responses to emotional stimuli with social content.

    PubMed

    Wardle, Margaret C; Kirkpatrick, Matthew G; de Wit, Harriet

    2014-08-01

    3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive 'prosocial' effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content. We hypothesized that MDMA would dose-dependently increase reactivity to positive emotional stimuli and dampen reactivity to negative stimuli, and that these effects would be most pronounced for pictures with people in them. The data were obtained from two studies using similar designs with healthy occasional MDMA users (total N = 101). During each session, participants received MDMA (0, 0.75 and 1.5 mg/kg oral), and then rated their positive and negative responses to standardized positive, negative and neutral pictures with and without social content. MDMA increased positive ratings of positive social pictures, but reduced positive ratings of non-social positive pictures. We speculate this 'socially selective' effect contributes to the prosocial effects of MDMA by increasing the comparative value of social contact and closeness with others. This effect may also contribute to its attractiveness to recreational users.

  3. 'Ecstasy' as a social drug: MDMA preferentially affects responses to emotional stimuli with social content.

    PubMed

    Wardle, Margaret C; Kirkpatrick, Matthew G; de Wit, Harriet

    2014-08-01

    3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive 'prosocial' effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content. We hypothesized that MDMA would dose-dependently increase reactivity to positive emotional stimuli and dampen reactivity to negative stimuli, and that these effects would be most pronounced for pictures with people in them. The data were obtained from two studies using similar designs with healthy occasional MDMA users (total N = 101). During each session, participants received MDMA (0, 0.75 and 1.5 mg/kg oral), and then rated their positive and negative responses to standardized positive, negative and neutral pictures with and without social content. MDMA increased positive ratings of positive social pictures, but reduced positive ratings of non-social positive pictures. We speculate this 'socially selective' effect contributes to the prosocial effects of MDMA by increasing the comparative value of social contact and closeness with others. This effect may also contribute to its attractiveness to recreational users. PMID:24682132

  4. Exploring Visuomotor Priming Following Biological and Non-Biological Stimuli

    ERIC Educational Resources Information Center

    Gowen, E.; Bradshaw, C.; Galpin, A.; Lawrence, A.; Poliakoff, E.

    2010-01-01

    Observation of human actions influences the observer's own motor system, termed visuomotor priming, and is believed to be caused by automatic activation of mirror neurons. Evidence suggests that priming effects are larger for biological (human) as opposed to non-biological (object) stimuli and enhanced when viewing stimuli in mirror compared to…

  5. Inhibition of premature ventricular extrastimuli by subthreshold conditioning stimuli.

    PubMed

    Skale, B T; Kallok, M J; Prystowsky, E N; Gill, R M; Zipes, D P

    1985-07-01

    The purpose of this study was to determine whether trains of subthreshold high frequency conditioning stimuli (333 Hz, 1 ms duration, 2 ms interval) delivered to the canine ventricle inhibited the response to a premature stimulus (S2) more effectively than did a single subthreshold conditioning stimulus. It was found that trains of conditioning stimuli (mean 1.21 mA) inhibited the response to S2 152 ms beyond expiration of the ventricular effective refractory period, whereas a single conditioning stimulus inhibited S2 only 20 ms or less beyond the ventricular effective refractory period. In late diastole, trains of conditioning stimuli failed to inhibit S2 when the train of stimuli caused ventricular depolarization or the latter occurred in response to the next sinus impulse. Trains of conditioning stimuli did not induce ventricular arrhythmias. Lidocaine or autonomic blockade did not alter the response to trains of conditioning stimuli. Trains of conditioning stimuli or a single conditioning stimulus inhibited the response to S2 only when they were delivered at the same electrode site. By lengthening the ventricular effective refractory period, trains of conditioning stimuli could prevent or terminate tachycardias, but this possibility is constrained, at present, by the spatial limitations of the technique.

  6. Conditional Reinforcers and Informative Stimuli in a Constant Environment

    ERIC Educational Resources Information Center

    Boutros, Nathalie; Davison, Michael; Elliffe, Douglas

    2009-01-01

    Five pigeons responded on steady-state concurrent variable-interval variable-interval schedules of food presentation in which half of the foods were removed and replaced with nonfood stimuli. Across conditions, the stimuli were either paired or unpaired with food, and the correlation between the ratio of food deliveries on the two alternatives and…

  7. Freeze or Flee? Negative Stimuli Elicit Selective Responding

    ERIC Educational Resources Information Center

    Estes, Zachary; Verges, Michelle

    2008-01-01

    Humans preferentially attend to negative stimuli. A consequence of this automatic vigilance for negative valence is that negative words elicit slower responses than neutral or positive words on a host of cognitive tasks. Some researchers have speculated that negative stimuli elicit a general suppression of motor activity, akin to the freezing…

  8. Logical Rules and the Classification of Integral-Dimension Stimuli

    ERIC Educational Resources Information Center

    Little, Daniel R.; Nosofsky, Robert M.; Donkin, Christopher; Denton, Stephen E.

    2013-01-01

    A classic distinction in perceptual information processing is whether stimuli are composed of separable dimensions, which are highly analyzable, or integral dimensions, which are processed holistically. Previous tests of a set of logical-rule models of classification have shown that separable-dimension stimuli are processed serially if the…

  9. Violent Reactions from Non-Shock Stimuli

    NASA Astrophysics Data System (ADS)

    Sandusky, Harold

    2007-06-01

    Most reactions are thermally initiated, whether from direct heating or dissipation of energy from mechanical, shock, or electrical stimuli. For other than prompt shock initiation, the reaction must be able to spread through porosity or over large surface area to become more violent than just rupturing any confinement. While burning rates are important, high-strain mechanical properties are nearly so, either by reducing existing porosity or generating additional surface area through fracture. The first example is deflagration-to-detonation transition (DDT) in porous beds. During the early stages, weak compressive waves ahead of the convective ignition front will reduce porosity, thereby restricting the spread of combustion and the pressure buildup. If, however, pressure increases faster than can be relieved by loss of confinement, coalescing compressive waves can initiate reaction at hot spots from rapid pore collapse. This compressive reaction can drive a shockwave that transits to detonation, the most violent reaction in any scenario. It has been shown that reaction violence is reduced in DDT experiments if the binder is softened, either by raising the initial temperature or adding a solvent. An example of the role of mechanical properties in enhancing reaction violence through fracturing occurs when cavities in projectile fills collapse during acceleration in the gun barrel, which is referred to as setback. Explosives with soft rubber binders will deform and undergo mild reaction from shear heating within the explosive and adiabatic compression of any gas in the cavity. Stiff explosives are similarly ignited, but also fracture and generate additional surface area for a violent event. The last example to be considered is slow cook-off, where thermal damage can increase burning rate as well as provide porosity to enhance the pressure buildup. As reaction spreads from the zone of thermal run-away, an explosive binder that resists breakup will limit the violence.

  10. Optimal Decision Stimuli for Risky Choice Experiments: An Adaptive Approach.

    PubMed

    Cavagnaro, Daniel R; Gonzalez, Richard; Myung, Jay I; Pitt, Mark A

    2013-02-01

    Collecting data to discriminate between models of risky choice requires careful selection of decision stimuli. Models of decision making aim to predict decisions across a wide range of possible stimuli, but practical limitations force experimenters to select only a handful of them for actual testing. Some stimuli are more diagnostic between models than others, so the choice of stimuli is critical. This paper provides the theoretical background and a methodological framework for adaptive selection of optimal stimuli for discriminating among models of risky choice. The approach, called Adaptive Design Optimization (ADO), adapts the stimulus in each experimental trial based on the results of the preceding trials. We demonstrate the validity of the approach with simulation studies aiming to discriminate Expected Utility, Weighted Expected Utility, Original Prospect Theory, and Cumulative Prospect Theory models. PMID:24532856

  11. Optimal Decision Stimuli for Risky Choice Experiments: An Adaptive Approach

    PubMed Central

    Cavagnaro, Daniel R.; Gonzalez, Richard; Myung, Jay I.; Pitt, Mark A.

    2014-01-01

    Collecting data to discriminate between models of risky choice requires careful selection of decision stimuli. Models of decision making aim to predict decisions across a wide range of possible stimuli, but practical limitations force experimenters to select only a handful of them for actual testing. Some stimuli are more diagnostic between models than others, so the choice of stimuli is critical. This paper provides the theoretical background and a methodological framework for adaptive selection of optimal stimuli for discriminating among models of risky choice. The approach, called Adaptive Design Optimization (ADO), adapts the stimulus in each experimental trial based on the results of the preceding trials. We demonstrate the validity of the approach with simulation studies aiming to discriminate Expected Utility, Weighted Expected Utility, Original Prospect Theory, and Cumulative Prospect Theory models. PMID:24532856

  12. Emotional attention for erotic stimuli: Cognitive and brain mechanisms.

    PubMed

    Sennwald, Vanessa; Pool, Eva; Brosch, Tobias; Delplanque, Sylvain; Bianchi-Demicheli, Francesco; Sander, David

    2016-06-01

    It has long been posited that among emotional stimuli, only negative threatening information modulates early shifts of attention. However, in the last few decades there has been an increase in research showing that attention is also involuntarily oriented toward positive rewarding stimuli such as babies, food, and erotic information. Because reproduction-related stimuli have some of the largest effects among positive stimuli on emotional attention, the present work reviews recent literature and proposes that the cognitive and cerebral mechanisms underlying the involuntarily attentional orientation toward threat-related information are also sensitive to erotic information. More specifically, the recent research suggests that both types of information involuntarily orient attention due to their concern relevance and that the amygdala plays an important role in detecting concern-relevant stimuli, thereby enhancing perceptual processing and influencing emotional attentional processes. PMID:26179894

  13. Affective Priming with Auditory Speech Stimuli

    ERIC Educational Resources Information Center

    Degner, Juliane

    2011-01-01

    Four experiments explored the applicability of auditory stimulus presentation in affective priming tasks. In Experiment 1, it was found that standard affective priming effects occur when prime and target words are presented simultaneously via headphones similar to a dichotic listening procedure. In Experiment 2, stimulus onset asynchrony (SOA) was…

  14. Implicit Training of Nonnative Speech Stimuli

    ERIC Educational Resources Information Center

    Vlahou, Eleni L.; Protopapas, Athanassios; Seitz, Aaron R.

    2012-01-01

    Learning nonnative speech contrasts in adulthood has proven difficult. Standard training methods have achieved moderate effects using explicit instructions and performance feedback. In this study, the authors question preexisting assumptions by demonstrating a superiority of implicit training procedures. They trained 3 groups of Greek adults on a…

  15. How Attention Modulates Encoding of Dynamic Stimuli

    PubMed Central

    Oren, Noga; Shapira-Lichter, Irit; Lerner, Yulia; Tarrasch, Ricardo; Hendler, Talma; Giladi, Nir; Ash, Elissa L.

    2016-01-01

    When encoding a real-life, continuous stimulus, the same neural circuits support processing and integration of prior as well as new incoming information. This ongoing interplay is modulated by attention, and is evident in regions such as the prefrontal cortex section of the task positive network (TPN), and in the posterior cingulate cortex (PCC), a hub of the default mode network (DMN). Yet the exact nature of such modulation is still unclear. To investigate this issue, we utilized an fMRI task that employed movies as the encoded stimuli and manipulated attentional load via an easy or hard secondary task that was performed simultaneously with encoding. Results showed increased intersubject correlation (inter-SC) levels when encoding movies in a condition of high, as compared to low attentional load. This was evident in bilateral ventrolateral and dorsomedial prefrontal cortices and the dorsal PCC (dPCC). These regions became more attuned to the combination of the movie and the secondary task as the attentional demand of the latter increased. Activation analyses revealed that at higher load the prefrontal TPN regions were more activated, whereas the dPCC was more deactivated. Attentional load also influenced connectivity within and between the networks. At high load the dPCC was anti-correlated to the prefrontal regions, which were more functionally coherent amongst themselves. Finally and critically, greater inter-SC in the dPCC at high load during encoding predicted lower memory strength when that information was retrieved. This association between inter-SC levels and memory strength suggest that as attentional demands increased, the dPCC was more attuned to the secondary task at the expense of the encoded stimulus, thus weakening memory for the encoded stimulus. Together, our findings show that attentional load modulated the function of core TPN and DMN regions. Furthermore, the observed relationship between memory strength and the modulation of the dPCC points

  16. Stimuli-Responsive Mechanically Adaptive Polymer Nanocomposites

    PubMed Central

    Shanmuganathan, Kadhiravan; Capadona, Jeffrey R.; Rowan, Stuart J.; Weder, Christoph

    2010-01-01

    A new series of biomimetic stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was prepared and investigated. The materials were produced by introducing percolating networks of cellulose nanofibers or “whiskers” derived from tunicates into poly(vinyl acetate) (PVAc), poly(butyl methacrylate) (PBMA), and blends of these polymers, with the objective of determining how the hydrophobicity and glass-transition temperature (Tg) of the polymer matrix affect the water-induced mechanically dynamic behavior. Below the Tg (~60–70 °C), the incorporation of whiskers (15.1 – 16.5% v/v) modestly increased the tensile storage moduli (E′) of the neat polymers from 0.6 to 3.8 GPa (PBMA) and from 2 to 5.2 GPa (PVAc). The reinforcement was much more dramatic above Tg, where E′ increased from 1.2 to 690 MPa (PVAc) and ~1 to 1.1 GPa (PBMA). Upon exposure to physiological conditions (immersion in artificial cerebrospinal fluid, ACSF, at 37 °C) all materials displayed a decrease of E′. The most significant contrast was seen in PVAc; for example the E′ of a 16.5% v/v PVAc/whisker nanocomposite decreased from 5.2 GPa to 12.7 MPa. Only a modest modulus decrease was measured for PBMA/whisker nanocomposite; here the E′ of a 15.1% v/v PBMA/whisker nanocomposite decreased from 3.8 to 1.2 GPa. A systematic investigation revealed that the magnitude of the mechanical contrast was related to the degree of swelling with ACSF, which was shown to increase with whisker content, temperature, and polarity of the matrix (PVAc > PBMA). The mechanical morphing of the new materials can be described in the framework of both the percolation and Halpin-Kardos models for nanocomposite reinforcement, and is the result of changing interactions among the nanoparticles and plasticization of the matrix upon swelling. PMID:20305827

  17. Dynamic bioactive stimuli-responsive polymeric surfaces

    NASA Astrophysics Data System (ADS)

    Pearson, Heather Marie

    This dissertation focuses on the design, synthesis, and development of antimicrobial and anticoagulant surfaces of polyethylene (PE), polypropylene (PP), and poly(tetrafluoroethylene) (PTFE) polymers. Aliphatic polymeric surfaces of PE and PP polymers functionalized using click chemistry reactions by the attachment of --COOH groups via microwave plasma reactions followed by functionalization with alkyne moieties. Azide containing ampicillin (AMP) was synthesized and subsequently clicked into the alkyne prepared PE and PP surfaces. Compared to non-functionalized PP and PE surfaces, the AMP clicked surfaces exhibited substantially enhanced antimicrobial activity against Staphylococcus aureus bacteria. To expand the biocompatibility of polymeric surface anticoagulant attributes, PE and PTFE surfaces were functionalized with pH-responsive poly(2-vinyl pyridine) (P2VP) and poly(acrylic acid) (PAA) polyelectrolyte tethers terminated with NH2 and COOH groups. The goal of these studies was to develop switchable stimuli-responsive polymeric surfaces that interact with biological environments and display simultaneous antimicrobial and anticoagulant properties. Antimicrobial AMP was covalently attached to --COOH terminal ends of protected PAA, while anticoagulant heparin (HEP) was attached to terminal --NH2 groups of P2VP. When pH < 2.3, the P2VP segments are protonated and extend, but for pH > 5.5, they collapse while the PAA segments extend. Such surfaces, when exposed to Staphylococcus aureus, inhibit bacterial growth due to the presence of AMP, as well as are effective anticoagulants due to the presence of covalently attached HEP. Comparison of these "dynamic" pH responsive surfaces with "static" surfaces terminated with AMP entities show significant enhancement of longevity and surface activity against microbial film formation. The last portion of this dissertation focuses on the covalent attachment of living T1 and Φ11 bacteriophages (phages) on PE and PTFE surface

  18. Numerosity judgments for tactile stimuli distributed over the body surface.

    PubMed

    Gallace, Alberto; Tan, Hong Z; Spence, Charles

    2006-01-01

    A large body of research now supports the claim that two different and dissociable processes are involved in making numerosity judgments regarding visual stimuli: subitising (fast and nearly errorless) for up to 4 stimuli, and counting (slow and error-prone) when more than 4 stimuli are presented. We studied tactile numerosity judgments for combinations of 1-7 vibrotactile stimuli presented simultaneously over the body surface. In experiment 1, the stimuli were presented once, while in experiment 2 conditions of single presentation and repeated presentation of the stimulus were compared. Neither experiment provided any evidence for a discontinuity in the slope of either the RT or error data suggesting that subitisation does not occur for tactile stimuli. By systematically varying the intensity of the vibrotactile stimuli in experiment 3, we were able to demonstrate that participants were not simply using the 'global intensity' of the whole tactile display to make their tactile numerosity judgments, but were, instead, using information concerning the number of tactors activated. The results of the three experiments reported here are discussed in relation to current theories of counting and subitising, and potential implications for the design of tactile user interfaces are highlighted. PMID:16583769

  19. Psychophysical definition of S-cone stimuli in the macaque

    PubMed Central

    Hall, Nathan; Colby, Carol

    2013-01-01

    We used the perceptual reports of nonhuman primates to perform psychophysical calibrations of S-cone isolating stimuli. S-cone stimuli were calibrated separately at several spatial locations for each monkey. To do this we exploited the effect of transient tritanopia, which causes a selective decrease of sensitivity in the observer's S-cone channel. At the start of each transient tritanopia trial monkeys were visually adapted to a bright yellow background. This type of adaptation is known to induce transient tritanopia. Calibrated S-cone isolating stimuli were determined by finding a near S-cone stimulus whose detection threshold was maximally elevated during transient tritanopia. At the start of each control trial, monkeys were adapted to a bright white background. In these trials, monkeys' detection thresholds for near S-cone stimuli were unchanged. We found that S-cone isolating stimuli could be determined at most locations tested in each monkey. Calibrated S-cone stimuli were particular to both spatial location and animal. To understand the visual system as a whole in vivo requires physiological methods not possible in human subjects. The present results open the door to novel behavioral and physiological experiments by showing that S-cone isolating stimuli can be calibrated in monkeys. PMID:23412341

  20. Transitive responding in hooded crows requires linearly ordered stimuli.

    PubMed Central

    Lazareva, Olga F; Smirnova, Anna A; Bagozkaja, Maria S; Zorina, Zoya A; Rayevsky, Vladimir V; Wasserman, Edward A

    2004-01-01

    Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These circles were made available for comparison to potentially help the crows order the stimuli along a physical dimension. For the other 4 birds, the circles corresponding to the colored cards had the same diameter (constant feedback group). In later testing, a novel choice pair (BD) was presented. Reinforcement history involving stimuli B and D was controlled so that the reinforcement/nonreinforcement ratios for the latter would be greater than for the former. If, during the BD test, the crows chose between stimuli according to these reinforcement/nonreinforcement ratios, then they should prefer D; if they chose according to the diameter of the feedback stimuli, then they should prefer B. In the ordered feedback group, the crows strongly preferred B over D; in the constant feedback group, the crows' choice did not differ significantly from chance. These results, plus simulations using associative models, suggest that the orderability of the postchoice feedback stimuli is important for crows' transitive responding. PMID:15484868

  1. The New Boss!

    ERIC Educational Resources Information Center

    Harvey, Carl, II

    2012-01-01

    It happens--retirement , resignation, promotion, or relocation can bring a new principal on to the scene. In some ways, it is like starting a whole new job. Sure, the staff, students, and building have remained the same, but there is a whole new person in the front office to figure out and that one person can make a huge difference in the school…

  2. Corporate Boss, College President

    ERIC Educational Resources Information Center

    Alden, Vernon R.

    1978-01-01

    Differences between the roles of a corporate administrator and a college president are reviewed and related to the role of an effective trustee. It is noted that accountability demands affect institutional autonomy and that trustees must become more involved in policy-making to protect the academic freedom of colleges and universities in the…

  3. An online brain-computer interface based on shifting attention to concurrent streams of auditory stimuli

    PubMed Central

    Hill, N J; Schölkopf, B

    2012-01-01

    We report on the development and online testing of an EEG-based brain-computer interface (BCI) that aims to be usable by completely paralysed users—for whom visual or motor-system-based BCIs may not be suitable, and among whom reports of successful BCI use have so far been very rare. The current approach exploits covert shifts of attention to auditory stimuli in a dichotic-listening stimulus design. To compare the efficacy of event-related potentials (ERPs) and steady-state auditory evoked potentials (SSAEPs), the stimuli were designed such that they elicited both ERPs and SSAEPs simultaneously. Trial-by-trial feedback was provided online, based on subjects’ modulation of N1 and P3 ERP components measured during single 5-second stimulation intervals. All 13 healthy subjects were able to use the BCI, with performance in a binary left/right choice task ranging from 75% to 96% correct across subjects (mean 85%). BCI classification was based on the contrast between stimuli in the attended stream and stimuli in the unattended stream, making use of every stimulus, rather than contrasting frequent standard and rare “oddball” stimuli. SSAEPs were assessed offline: for all subjects, spectral components at the two exactly-known modulation frequencies allowed discrimination of pre-stimulus from stimulus intervals, and of left-only stimuli from right-only stimuli when one side of the dichotic stimulus pair was muted. However, attention-modulation of SSAEPs was not sufficient for single-trial BCI communication, even when the subject’s attention was clearly focused well enough to allow classification of the same trials via ERPs. ERPs clearly provided a superior basis for BCI. The ERP results are a promising step towards the development of a simple-to-use, reliable yes/no communication system for users in the most severely paralysed states, as well as potential attention-monitoring and -training applications outside the context of assistive technology. PMID:22333135

  4. Processing of invisible stimuli: advantage of upright faces and recognizable words in overcoming interocular suppression.

    PubMed

    Jiang, Yi; Costello, Patricia; He, Sheng

    2007-04-01

    Familiar and recognizable stimuli enjoy an advantage of predominance during binocular rivalry, and this advantage is usually attributed to their enhanced processing during the dominant phase. However, do familiar and recognizable stimuli have an advantage in breaking suppression? Test images were gradually introduced to one eye to compete against a standard high-contrast dynamic noise pattern presented to the other eye. Results showed that an upright face took less time than an upside-down face to gain dominance against the identical suppression noise. Results also showed that for Chinese readers, Chinese characters were faster to gain dominance than Hebrew words, whereas for Hebrew readers, the reverse was true. These results suggest that familiar and recognizable information, even when suppressed and invisible, is processed differently from unfamiliar information. Apparently, high-level information about visual form does contribute to the strength of a stimulus during its suppressed phase.

  5. Exploring strategies for classification of external stimuli using statistical features of the plant electrical response

    PubMed Central

    Chatterjee, Shre Kumar; Das, Saptarshi; Maharatna, Koushik; Masi, Elisa; Santopolo, Luisa; Mancuso, Stefano; Vitaletti, Andrea

    2015-01-01

    Plants sense their environment by producing electrical signals which in essence represent changes in underlying physiological processes. These electrical signals, when monitored, show both stochastic and deterministic dynamics. In this paper, we compute 11 statistical features from the raw non-stationary plant electrical signal time series to classify the stimulus applied (causing the electrical signal). By using different discriminant analysis-based classification techniques, we successfully establish that there is enough information in the raw electrical signal to classify the stimuli. In the process, we also propose two standard features which consistently give good classification results for three types of stimuli—sodium chloride (NaCl), sulfuric acid (H2SO4) and ozone (O3). This may facilitate reduction in the complexity involved in computing all the features for online classification of similar external stimuli in future. PMID:25631569

  6. Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye

    PubMed Central

    Maguire, John; Parry, Neil R. A.; Kremers, Jan; Kommanapalli, Deepika; Murray, Ian J.; McKeefry, Declan J.

    2016-01-01

    Purpose To demonstrate that silent substitution stimuli can be used to generate electroretinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation, and that this approach constitutes a viable alternative to current clinical standard testing protocols. Methods Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary light-emitting diode (LED) Ganzfeld stimulator to elicit ERGs from participants with normal and compromised rod function who had not undergone dark-adaptation. Responses were subjected to Fourier analysis, and the amplitude and phase of the fundamental were used to examine temporal frequency and retinal illuminance response characteristics. Results Electroretinograms elicited by rod-isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30 Hz. Responses are optimal between 5 and 8 Hz and between 10 and 100 photopic trolands (Td). There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. Analysis of signal-to-noise ratios reveals significant differences between subjects with normal and compromised rod function. Conclusions Silent substitution provides an effective method for the isolation of human rod photoreceptor function in subjects with normal as well as compromised rod function when stimuli are used within appropriate parameter ranges. Translational Relevance This method of generating rod-mediated ERGs can be achieved without time-consuming periods of dark adaptation, provides improved isolation of rod- from cone-based activity, and will lead to the development of faster clinical electrophysiologic testing protocols with improved selectivity.

  7. Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye

    PubMed Central

    Maguire, John; Parry, Neil R. A.; Kremers, Jan; Kommanapalli, Deepika; Murray, Ian J.; McKeefry, Declan J.

    2016-01-01

    Purpose To demonstrate that silent substitution stimuli can be used to generate electroretinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation, and that this approach constitutes a viable alternative to current clinical standard testing protocols. Methods Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary light-emitting diode (LED) Ganzfeld stimulator to elicit ERGs from participants with normal and compromised rod function who had not undergone dark-adaptation. Responses were subjected to Fourier analysis, and the amplitude and phase of the fundamental were used to examine temporal frequency and retinal illuminance response characteristics. Results Electroretinograms elicited by rod-isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30 Hz. Responses are optimal between 5 and 8 Hz and between 10 and 100 photopic trolands (Td). There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. Analysis of signal-to-noise ratios reveals significant differences between subjects with normal and compromised rod function. Conclusions Silent substitution provides an effective method for the isolation of human rod photoreceptor function in subjects with normal as well as compromised rod function when stimuli are used within appropriate parameter ranges. Translational Relevance This method of generating rod-mediated ERGs can be achieved without time-consuming periods of dark adaptation, provides improved isolation of rod- from cone-based activity, and will lead to the development of faster clinical electrophysiologic testing protocols with improved selectivity. PMID:27617180

  8. CLE Peptide Signaling and Crosstalk with Phytohormones and Environmental Stimuli.

    PubMed

    Wang, Guodong; Zhang, Guohua; Wu, Mengyao

    2015-01-01

    The CLE (CLAVATA3/Endosperm surrounding region-related) peptide family is one of the best-studied secreted peptide families in plants. Accumulated data have revealed that CLE genes play vital roles on stem cell homeostasis in different types of meristems. Additionally, CLE genes have been found to perform various biological roles in plant growth and development, and in response to environmental stimuli. With recent advances on our understanding of CLE peptide function, it is showing that the existence of potential crosstalks of CLE peptides with phytohormones and external stimuli. Complex interactions exist in which CLE petides coordinate with hormones to regulate plant growth and development, and in response to external stimuli. In this article, we present recent advances in cell-cell communication that is mediated by CLE peptides combining with phytohormones and external stimuli, and suggest additional Arabidopsis CLE genes that are likely to be controlled by hormones and environmental cues. PMID:26779239

  9. Do extraverts process social stimuli differently from introverts?

    PubMed Central

    Fishman, Inna; Ng, Rowena; Bellugi, Ursula

    2011-01-01

    The personality trait of extraversion has been linked to the network of brain systems controlling sensitivity to cues of reward and generating approach behavior in response, but little is known about whether extraverts’ neural circuits are especially sensitive to social stimuli, given their preference for social engagement. Utilizing event-related potential (ERP) methodology, this study demonstrates that variation on the extraversion dimension is associated with the extent to which social stimuli evoke enhanced allocation of attention. Specifically, higher scores on extraversion were found to be associated with higher amplitudes of the P300 component of the ERPs elicited by human faces. This finding suggests that social stimuli carry enhanced motivational significance for individuals characterized by high extraversion, and that individual differences in personality are related to meaningful individual differences in neural responses to social stimuli. PMID:21738558

  10. Prism adaptation contrasts perceptual habituation for repetitive somatosensory stimuli.

    PubMed

    Torta, D M; Tatu, M K; Cotroneo, D; Alamia, A; Folegatti, A; Trojan, J

    2016-03-01

    Prism adaptation (PA) is a non-invasive procedure that requires performing a visuo-motor pointing task while wearing prism goggles inducing a visual displacement of the pointed target. This procedure involves a reorganization of sensorimotor coordination, and induces long-lasting effects on numerous higher-order cognitive functions in healthy volunteers and neglect patients. Prismatic displacement (PD) of the visual field can be induced when prisms are worn but no sensorimotor task is required. In this case, it is unlikely that any subsequent reorganization takes place. The effects of PD are short-lived in the sense that they last as long as prisms are worn. In this study we aimed, to the best of our knowledge for the first time, at investigating whether PA and PD induce changes in the perception of intensity of nociceptive and non- nociceptive somatosensory stimuli. We induced, in healthy volunteers, PD (experiment 1), or PA (experiment 2) and asked participants to rate the intensity of the stimuli applied to the hand undergoing the visuo-proprioceptive conflict (experiment 1) or adaptation (experiment 2). Our results indicate that: 1) the visuo-proprioceptive conflict induced by PD does not reduce the perceived intensity of the stimuli, 2) PA prevents perceptual habituation for both nociceptive and non-nociceptive somatosensory stimuli. Moreover, to investigate the possible underlying mechanisms of the effects of PA we conducted a third experiment in which stimuli were applied both at the adapted and the non-adapted hand. In line with the results of experiment 2, we found that perceptual habituation was prevented for stimuli applied onto the adapted hand. Moreover, we observed the same finding for stimuli applied onto the non-adapted hand. This result suggests that the detention of habituation is not merely driven by changes in spatial attention allocation. Taken together, these data indicate that prisms can affect the perceived intensity of somatosensory stimuli

  11. Multisensory numerosity judgments for visual and tactile stimuli.

    PubMed

    Gallace, Alberto; Tan, Hong Z; Spence, Charles

    2007-05-01

    To date, numerosity judgments have been studied only under conditions of unimodal stimulus presentation. It is therefore unclear whether the same limitations on correctly reporting the number of unimodal visual or tactile stimuli presented in a display might be expected under conditions in which participants have to count stimuli presented simultaneously in two or more different sensory modalities. In Experiment 1, we investigated numerosity judgments using both unimodal and bimodal displays consisting of one to six vibrotactile stimuli (presented over the body surface) and one to six visual stimuli (seen on the body via mirror reflection). Participants had to count the number of stimuli regardless of their modality of presentation. Bimodal numerosity judgments were significantly less accurate than predicted on the basis of an independent modality-specific resources account, thus showing that numerosity judgments might rely on a unitary amodal system instead. The results of a second experiment demonstrated that divided attention costs could not account for the poor performance in the bimodal conditions of Experiment 1. We discuss these results in relation to current theories of cross-modal integration and to the cognitive resources and/or common higher order spatial representations possibly accessed by both visual and tactile stimuli. PMID:17727102

  12. siRNA Delivery by Stimuli-Sensitive Nanocarriers

    PubMed Central

    Salzano, Giuseppina; Costa, Daniel F.; Torchilin, Vladimir P.

    2016-01-01

    Since its discovery in late 1990s, small interfering RNA (siRNA) has become a significant biopharmaceutical research tool and a powerful option for the treatment of different human diseases based on altered gene-expression. Despite promising data from many pre-clinical studies, concrete hurdles still need to be overcome to bring therapeutic siRNAs in clinic. The design of stimuli-sensitive nanopreparations for gene therapy is a lively area of the current research. Compared to conventional systems for siRNA delivery, this type of platform can respond to local stimuli that are characteristics of the pathological area of interest, allowing the release of nucleic acids at the desired site. Acidic pH, abnormal levels of enzymes, altered redox potential and magnetic field are examples of stimuli exploited in the design of stimuli-sensitive nanoparticles. In this review, we discuss on recent stimuli-sensitive strategies for siRNA delivery and we highlight on the potential of combining multiple stimuli-sensitive strategies in the same nano-platform for a better therapeutic outcome. PMID:26486143

  13. Bitter Taste Stimuli Induce Differential Neural Codes in Mouse Brain

    PubMed Central

    Wilson, David M.; Boughter, John D.; Lemon, Christian H.

    2012-01-01

    A growing literature suggests taste stimuli commonly classified as “bitter” induce heterogeneous neural and perceptual responses. Here, the central processing of bitter stimuli was studied in mice with genetically controlled bitter taste profiles. Using these mice removed genetic heterogeneity as a factor influencing gustatory neural codes for bitter stimuli. Electrophysiological activity (spikes) was recorded from single neurons in the nucleus tractus solitarius during oral delivery of taste solutions (26 total), including concentration series of the bitter tastants quinine, denatonium benzoate, cycloheximide, and sucrose octaacetate (SOA), presented to the whole mouth for 5 s. Seventy-nine neurons were sampled; in many cases multiple cells (2 to 5) were recorded from a mouse. Results showed bitter stimuli induced variable gustatory activity. For example, although some neurons responded robustly to quinine and cycloheximide, others displayed concentration-dependent activity (p<0.05) to quinine but not cycloheximide. Differential activity to bitter stimuli was observed across multiple neurons recorded from one animal in several mice. Across all cells, quinine and denatonium induced correlated spatial responses that differed (p<0.05) from those to cycloheximide and SOA. Modeling spatiotemporal neural ensemble activity revealed responses to quinine/denatonium and cycloheximide/SOA diverged during only an early, at least 1 s wide period of the taste response. Our findings highlight how temporal features of sensory processing contribute differences among bitter taste codes and build on data suggesting heterogeneity among “bitter” stimuli, data that challenge a strict monoguesia model for the bitter quality. PMID:22844505

  14. The high-mass end of the red sequence at z ˜ 0.55 from SDSS-III/BOSS: completeness, bimodality and luminosity function

    NASA Astrophysics Data System (ADS)

    Montero-Dorta, Antonio D.; Bolton, Adam S.; Brownstein, Joel R.; Swanson, Molly; Dawson, Kyle; Prada, Francisco; Eisenstein, Daniel; Maraston, Claudia; Thomas, Daniel; Comparat, Johan; Chuang, Chia-Hsun; McBride, Cameron K.; Favole, Ginevra; Guo, Hong; Rodríguez-Torres, Sergio; Schneider, Donald P.

    2016-09-01

    We have developed an analytical method based on forward-modelling techniques to characterize the high-mass end of the red sequence (RS) galaxy population at redshift z ˜ 0.55, from the DR10 BOSS (Baryon Oscillation Spectroscopic Survey) CMASS spectroscopic sample, which comprises ˜600 000 galaxies. The method, which follows an unbinned maximum likelihood approach, allows the deconvolution of the intrinsic CMASS colour-colour-magnitude distributions from photometric errors and selection effects. This procedure requires modelling the covariance matrix for the i-band magnitude, g - r colour and r - i colour using Stripe 82 multi-epoch data. Our results indicate that the error-deconvolved intrinsic RS distribution is consistent, within the photometric uncertainties, with a single point (<0.05 mag) in the colour-colour plane at fixed magnitude, for a narrow redshift slice. We have computed the high-mass end (0.55Mi ≲ -22) of the 0.55i-band RS luminosity function (RS LF) in several redshift slices within the redshift range 0.52 < z < 0.63. In this narrow redshift range, the evolution of the RS LF is consistent, within the uncertainties in the modelling, with a passively evolving model with Φ* = (7.248 ± 0.204) × 10- 4 Mpc-3 mag-1, fading at a rate of 1.5 ± 0.4 mag per unit redshift. We report RS completeness as a function of magnitude and redshift in the CMASS sample, which will facilitate a variety of galaxy-evolution and clustering studies using BOSS. Our forward-modelling method lays the foundations for future studies using other dark-energy surveys like the Extended Baryon Oscillation Spectroscopic Survey or the Dark Energy Spectroscopic Instrument, which are affected by the same type of photometric blurring/selection effects.

  15. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Percival, Will J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Samushia, Lado; Schlegel, David J.; Thomas, Daniel; Tinker, Jeremy L.; Zhao, Gong-Bo

    2016-08-01

    We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line of sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12. The LOWZ sample contains 361 762 galaxies with an effective redshift of zlowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of zcmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations σ8 by modelling the redshift-space distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on fσ8, the product of the Hubble constant and the comoving sound horizon at the baryon-drag epoch H(z)rs(zd), and the angular distance parameter divided by the sound horizon DA(z)/rs(zd). We find f(zlowz)σ8(zlowz) = 0.394 ± 0.062, DA(zlowz)/rs(zd) = 6.35 ± 0.19, H(zlowz)rs(zd) = (11.41 ± 0.56) 103 km s- 1 for the LOWZ sample, and f(zcmass)σ8(zcmass) = 0.444 ± 0.038, DA(zcmass)/rs(zd) = 9.42 ± 0.15, H(zcmass)rs(zd) = (13.92 ± 0.44) 103 km s- 1 for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial Λcold dark matter values, we find f(zlowz)σ8(zlowz) = 0.485 ± 0.044 and f(zcmass)σ8(zcmass) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.

  16. Central effects of acetylsalicylic acid on trigeminal-nociceptive stimuli

    PubMed Central

    2014-01-01

    Background Acetylsalicylic acid is one of the most used analgesics to treat an acute migraine attack. Next to the inhibitory effects on peripheral prostaglandin synthesis, central mechanisms of action have also been discussed. Methods Using a standardized model for trigeminal-nociceptive stimulation during fMRI scanning, we investigated the effect of acetylsalicylic acid on acute pain compared to saline in 22 healthy volunteers in a double-blind within-subject design. Painful stimulation was applied using gaseous ammonia and presented in a pseudo-randomized order with several control stimuli. All participants were instructed to rate the intensity and unpleasantness of every stimulus on a VAS scale. Based on previous results, we hypothesized to find an effect of ASA on central pain processing structures like the ACC, SI and SII as well as the trigeminal nuclei and the hypothalamus. Results Even though we did not find any differences in pain ratings between saline and ASA, we observed decreased BOLD signal changes in response to trigemino-nociceptive stimulation in the ACC and SII after administration of ASA compared to saline. This finding is in line with earlier imaging results investigating the effect of ASA on acute pain. Contrary to earlier findings from animal studies, we could not find an effect of ASA on the trigeminal nuclei in the brainstem or within the hypothalamic area. Conclusion Taken together our study replicates earlier findings of an attenuating effect of ASA on pain processing structures, which adds further evidence to a possibly central mechanism of action of ASA. PMID:25201152

  17. Occurrence and causing stimuli of postoperative sensitivity in composite restorations.

    PubMed

    Auschill, Thorsten M; Koch, Christine A; Wolkewitz, Martin; Hellwig, Elmar; Arweiler, Nicole B

    2009-01-01

    Despite improvements in composite treatments over the past decade, postoperative sensitivity still remains a problem. Therefore, this clinical study evaluated the appearance of postoperative sensitivity after composite treatments and the stimuli that may have caused it. A total of 600 teeth in 231 patients was included in this study. All treatments were performed by dental students working under close supervision following standard procedures and using the bonding system Optibond FL and the nanofilled composite Ceram X. At baseline (visit 1), the restorations were grouped according to the following criteria: use of anesthesia, use of a rubber dam, indication for the restoration treatment, cavity class and clinical dimension of the cavity. After approximately two weeks (at visit 2), all the restorations were assessed and failure was defined if one of the following criteria occurred: a negative reaction to the vitality test, postoperative pain from masticatory forces or reported postoperative sensitivity by the patient. The reported postoperative sensitivity was specified with a visual analogue scale into hot/cold-sensitivity, sweet/soursensitivity, sharp/dull-sensitivity, spontaneous sensitivity and blistering/stinging-sensitivity. Failure was observed in 6% of the restorations. The statistical analysis showed that the clinical cavity depth turned out to be the only factor to have a significant influence on the appearance of postoperative sensitivity: caries profunda showed a four times higher risk of failure, while cavities with pulp exposure had a 14 times higher failure risk compared to restorations that were localized in the dentin. With regard to the type of sensitivity, no patients reported sensitivity to sweet/sour; most of them described their sensitivity as sharp/dull. PMID:19192831

  18. Electrodermal and behavioral responses of children with autism spectrum disorders to sensory and repetitive stimuli.

    PubMed

    McCormick, Carolyn; Hessl, David; Macari, Suzanne L; Ozonoff, Sally; Green, Cherie; Rogers, Sally J

    2014-08-01

    Parents frequently report that their children with autism spectrum disorders (ASD) respond atypically to sensory stimuli. Repetitive behaviors are also part of the ASD behavioral profile. Abnormal physiological arousal may underlie both of these symptoms. Electrodermal activity (EDA) is an index of sympathetic nervous system arousal. The goals of this study were twofold: (1) to pilot methods for collecting EDA data in young children and (2) to examine hypothesized relationships among EDA, and sensory symptoms and repetitive behaviors in children with ASD as compared with children with typical development. EDA was recorded on 54 young children with ASD and on 33 children with typical development (TD) during a protocol that included baseline, exposure to sensory and repetitive stimuli, and play. Parents completed standardized questionnaires regarding their child's sensory symptoms and repetitive behaviors. Frequency and type of repetitive behavior during play was coded offline. Comparisons between EDA data for ASD and TD groups indicated no significant between-group differences in any measures. Parents of children with ASD reported more abnormal responses to sensory stimuli and more repetitive behaviors, but scores on these measures were not significantly correlated with EDA or with frequency of observed repetitive behaviors. Parent report of frequency and severity of sensory symptoms was significantly correlated with reports of repetitive behaviors in both groups. Although parents of children with ASD report high levels of sensory symptoms and repetitive behaviors, these differences are not related to measured EDA arousal or reactivity. PMID:24788961

  19. Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts.

    PubMed

    Ramachandra, Abhay B; Kahn, Andrew M; Marsden, Alison L

    2016-08-01

    Mechanical stimuli are key to understanding disease progression and clinically observed differences in failure rates between arterial and venous grafts following coronary artery bypass graft surgery. We quantify biologically relevant mechanical stimuli, not available from standard imaging, in patient-specific simulations incorporating non-invasive clinical data. We couple CFD with closed-loop circulatory physiology models to quantify biologically relevant indices, including wall shear, oscillatory shear, and wall strain. We account for vessel-specific material properties in simulating vessel wall deformation. Wall shear was significantly lower (p = 0.014*) and atheroprone area significantly higher (p = 0.040*) in venous compared to arterial grafts. Wall strain in venous grafts was significantly lower (p = 0.003*) than in arterial grafts while no significant difference was observed in oscillatory shear index. Simulations demonstrate significant differences in mechanical stimuli acting on venous vs. arterial grafts, in line with clinically observed graft failure rates, offering a promising avenue for stratifying patients at risk for graft failure. PMID:27447176

  20. Neural mechanisms by which gravitational stimuli and stress affect the secretion of renin and other hormones

    NASA Technical Reports Server (NTRS)

    Ganong, William F.

    1987-01-01

    The present goal is to determine by the production of discrete lesions the parts of the hypothalamus and brainstem that are involved in serotonin-mediated increases in renin secretion. A variety of stimuli which act in different ways to increase renin stimuli were developed and standardized. The experiments with p-chloroamphetamine (PCA) demonstrated that there is a serotonergic pathway which projects from the dorsal raphe nuclei to the paraventricular nuclei and the vetromedial nuclei of the hypothalamus; that projection from paraventricular nuclei to the brainstem and spinal cord may be oxytocinergic; and that the pathway from the spinal cord to the renin secreting cells is sympathetic. The demonstration that paraventicular lesions lower circulating renin substrate is important because it raises the possibility that substrate secretion is under neural control, either via the pituitary or by direct neural pathways. The discovery that lesions of the ventromedial nuclei appear to abolish the increase in renin secretion produced by many different stimuli without affecting the concentration of renin substrate in the plasma makes the position of the hypothalamus in the regulation of fluid and electrolyte balance more prominent than previously suspected.

  1. The Floor Projection Maze: A novel behavioral apparatus for presenting visual stimuli to rats

    PubMed Central

    Furtak, Sharon C.; Cho, Christine E.; Kerr, Kristin M.; Barredo, Jennifer L.; Alleyne, Janelle E.; Patterson, Yolanda R.; Burwell, Rebecca D.

    2010-01-01

    There is a long tradition of studying visual learning in rats by presenting stimuli vertically on cards or monitors. The procedures are often labor intensive and the rate of acquisition can be prohibitively low. Available evidence suggests that rats process visual information presented in the lower visual hemifield more effectively than information presented in the upper visual hemifield. We capitalized on these findings by developing a novel apparatus, the Floor Projection Maze, for presenting visual information directly to the floor of an exploratory maze. Two-dimensional (2D) visual stimuli were presented on the floor by back-projecting an image from a standard digital projector to the semi-transparent underside of the floor of an open maze. Long-Evans rats rapidly acquired easy 2D visual discriminations (Experiment 1). Rats were also able to learn a more difficult shape discrimination in dramatically fewer trials than previously reported for the same discrimination when presented vertically (Experiment 2). The two choice discrimination task was adapted to determine contrast sensitivity thresholds in a naïve group of rats (Experiment 3). Contrast sensitivity thresholds were uniform across three subjects, demonstrating that the Floor Projection Maze can be used for visual psychophysics in rats. Our findings demonstrate that rats can rapidly acquire visual tasks when stimuli are presented horizontally on the floor, suggesting that this novel behavioral apparatus will provide a powerful behavioral paradigm in the future. PMID:19422855

  2. Electrodermal and behavioral responses of children with autism spectrum disorders to sensory and repetitive stimuli.

    PubMed

    McCormick, Carolyn; Hessl, David; Macari, Suzanne L; Ozonoff, Sally; Green, Cherie; Rogers, Sally J

    2014-08-01

    Parents frequently report that their children with autism spectrum disorders (ASD) respond atypically to sensory stimuli. Repetitive behaviors are also part of the ASD behavioral profile. Abnormal physiological arousal may underlie both of these symptoms. Electrodermal activity (EDA) is an index of sympathetic nervous system arousal. The goals of this study were twofold: (1) to pilot methods for collecting EDA data in young children and (2) to examine hypothesized relationships among EDA, and sensory symptoms and repetitive behaviors in children with ASD as compared with children with typical development. EDA was recorded on 54 young children with ASD and on 33 children with typical development (TD) during a protocol that included baseline, exposure to sensory and repetitive stimuli, and play. Parents completed standardized questionnaires regarding their child's sensory symptoms and repetitive behaviors. Frequency and type of repetitive behavior during play was coded offline. Comparisons between EDA data for ASD and TD groups indicated no significant between-group differences in any measures. Parents of children with ASD reported more abnormal responses to sensory stimuli and more repetitive behaviors, but scores on these measures were not significantly correlated with EDA or with frequency of observed repetitive behaviors. Parent report of frequency and severity of sensory symptoms was significantly correlated with reports of repetitive behaviors in both groups. Although parents of children with ASD report high levels of sensory symptoms and repetitive behaviors, these differences are not related to measured EDA arousal or reactivity.

  3. Logical rules and the classification of integral-dimension stimuli.

    PubMed

    Little, Daniel R; Nosofsky, Robert M; Donkin, Christopher; Denton, Stephen E

    2013-05-01

    A classic distinction in perceptual information processing is whether stimuli are composed of separable dimensions, which are highly analyzable, or integral dimensions, which are processed holistically. Previous tests of a set of logical-rule models of classification have shown that separable-dimension stimuli are processed serially if the dimensions are spatially separated and as a mixture of serial and parallel processes if the dimensions are spatially overlapping (Fifić, Little, & Nosofsky, 2010; Little, Nosofsky, & Denton, 2011). In the current research, the logical-rule models are applied to predict response-time (RT) data from participants trained to classify integral-dimension color stimuli into rule-based categories. In dramatic contrast to the previous results for separable-dimension stimuli, analysis of the current data indicated that processing was best captured by a single-channel coactive model. The results converge with previous operations that suggest holistic processing of integral-dimension stimuli and demonstrate considerable generality for the application of the logical-rule models to predicting RT data from rule-based classification experiments.

  4. Differing ERP patterns caused by suction and puff stimuli.

    PubMed

    Choi, Mi-Hyun; Kim, Hyung-Sik; Baek, Ji-Hye; Lee, Jung-Chul; Park, Sung-Jun; Jeong, Ul-Ho; Gim, Seon-Young; You, Ji Hye; Kim, Sung-Pil; Lim, Dae-Woon; Kim, Hyun-Jun; Chung, Soon-Cheol

    2015-05-01

    The present study compared event-related potential (ERP) patterns for two stimuli types, puff and suction, by applying these stimuli to the fingers; ERP patterns for the two stimuli were compared at C3, an area related to somatosensory perception, and at FC5, an area related to motor function. Participants were 12 healthy males in their 20s (mean age=23.1±2.0 years). One session consisted of a Control Phase (3s), a Stimulation Phase (3s), and a Rest Phase (9s). During the Stimulation Phase, a 4-psi suction or puff stimulus was applied to the first joint of the right index finger. After completion of the session, a subjective magnitude test was presented. In all phases, electroencephalography signals were recorded. We extracted maximum positive amplitude and minimum negative amplitude as well as relevant latency values for C3 and FC5 signals. Suction and puff stimuli had similar subjective magnitude scores. For both C3 and FC5, the maximum and minimum amplitude latency was reached earlier for the suction stimulus than for the puff stimulus. In conclusion, when suction and puff stimuli of the same intensity were applied to the fingers, the suction stimulus caused a more sensitive response in the somatosensory area (C3) and motor area (FC5) than did the puff stimulus.

  5. Individual mouse taste cells respond to multiple chemical stimuli

    PubMed Central

    Caicedo, Alejandro; Kim, Kyung-Nyun; Roper, Stephen D

    2002-01-01

    Sensory organs are specialized to detect and decode stimuli in terms of intensity and quality. In the gustatory system, the process of identifying and distinguishing taste qualities (e.g. bitter versus sweet) begins in taste buds. A central question in gustatory research is how information about taste quality is extracted by taste receptor cells. For instance, whether and how individual taste cells respond to multiple chemical stimuli is still a matter for debate. A recent study showed that taste cells expressing bitter-responsive taste receptors do not also express sweet-responsive taste receptors and vice versa. These results suggest that the gustatory system may use separate cellular pathways to process bitter and sweet signals independently. Results from electrophysiological studies, however, reveal that individual taste receptor cells respond to stimuli representing multiple taste qualities. Here we used non-invasive Ca2+ imaging in slices of lingual tissue containing taste buds to address the issue of quality detection in murine taste receptor cells. We recorded calcium transients elicited by chemical stimuli representing different taste qualities (sweet, salty, sour and bitter). Many receptor cells (38 %) responded to multiple taste qualities, with some taste cells responding to both appetitive (‘sweet’) and aversive (‘bitter’) stimuli. Thus, there appears to be no strict and separate detection of taste qualities by distinct subpopulations of taste cells in peripheral gustatory sensory organs in mice. PMID:12381822

  6. Effects of complex aural stimuli on mental performance.

    PubMed

    Vij, Mohit; Aghazadeh, Fereydoun; Ray, Thomas G; Hatipkarasulu, Selen

    2003-06-01

    The objective of this study is to investigate the effect of complex aural stimuli on mental performance. A series of experiments were designed to obtain data for two different analyses. The first analysis is a "Stimulus" versus "No-stimulus" comparison for each of the four dependent variables, i.e. quantitative ability, reasoning ability, spatial ability and memory of an individual, by comparing the control treatment with the rest of the treatments. The second set of analysis is a multi-variant analysis of variance for component level main effects and interactions. The two component factors are tempo of the complex aural stimuli and sound volume level, each administered at three discrete levels for all four dependent variables. Ten experiments were conducted on eleven subjects. It was found that complex aural stimuli influence the quantitative and spatial aspect of the mind, while the reasoning ability was unaffected by the stimuli. Although memory showed a trend to be worse with the presence of complex aural stimuli, the effect was statistically insignificant. Variation in tempo and sound volume level of an aural stimulus did not significantly affect the mental performance of an individual. The results of these experiments can be effectively used in designing work environments. PMID:15176128

  7. Private Stimuli, Covert Responses, and Private Events: Conceptual Remarks

    PubMed Central

    Tourinho, Emmanuel Zagury

    2006-01-01

    In this article, I discuss the concepts of private stimuli, covert responses, and private events, emphasizing three aspects: the conditions under which private stimuli may acquire discriminative functions to verbal responses, the conditions of unobservability of covert responses, and the complexity of events or phenomena described as private. I argue that the role of private stimuli in the control of self-descriptive verbal responses is dependent on a relation (correlation or equivalence relation) with public stimuli, and that responses vary along a continuum of observability. These remarks on private stimuli and covert responses are introductory to an examination of the varying complexity of phenomena described as private. I argue that private events is a verbal response emitted under the control of phenomena of different degrees of complexity, and I interpret these phenomena, based on the principle of selection by consequences. I introduce the notion of inclusiveness to suggest that some phenomena related to privacy are less or more complex as they include relations of a phylogenetic, ontogenetic, and cultural origin. PMID:22478451

  8. siRNA Delivery by Stimuli-Sensitive Nanocarriers.

    PubMed

    Salzano, Giuseppina; Costa, Daniel F; Torchilin, Vladimir P

    2015-01-01

    Since its discovery in the late 1990, small interfering RNA (siRNA) have quickly crept into the biopharmaceutical research as a new and powerful tool for the treatment of different human diseases based on altered gene-expression. Despite promising data from many pre-clinical studies, concrete hurdles still need to be overcome to bring therapeutic siRNAs in clinic. The design of stimuli-sensitive nanopreparations for gene therapy is a lively area of the current research. Compared to conventional systems for siRNA delivery, this type of platform can respond to local stimuli that are characteristics of the pathological area of interest, allowing the release of nucleic acids at the desired site. Acidic pH, de-regulated levels of enzymes, altered redox potential and magnetic field are examples of stimuli exploit to design stimuli-sensitive nanoparticles. In this review, we discuss on recent stimulisensitive strategies for siRNA delivery and we highlight on the potential of combining multiple stimuli-sensitive strategies in the same nano-platform for a better therapeutic outcome. PMID:26486143

  9. Evidence accumulation in a complex task: Making choices about concurrent multiattribute stimuli under time pressure.

    PubMed

    Palada, Hector; Neal, Andrew; Vuckovic, Anita; Martin, Russell; Samuels, Kate; Heathcote, Andrew

    2016-03-01

    Evidence accumulation models transform observed choices and associated response times into psychologically meaningful constructs such as the strength of evidence and the degree of caution. Standard versions of these models were developed for rapid (∼1 s) choices about simple stimuli, and have recently been elaborated to some degree to address more complex stimuli and response methods. However, these elaborations can be difficult to use with designs and measurements typically encountered in complex applied settings. We test the applicability of 2 standard accumulation models-the diffusion (Ratcliff & McKoon, 2008) and the linear ballistic accumulation (LBA) (Brown & Heathcote, 2008)-to data from a task representative of many applied situations: the detection of heterogeneous multiattribute targets in a simulated unmanned aerial vehicle (UAV) operator task. Despite responses taking more than 2 s and complications added by realistic features, such as a complex target classification rule, interruptions from a simultaneous UAV navigation task, and time pressured choices about several concurrently present potential targets, these models performed well descriptively. They also provided a coherent psychological explanation of the effects of decision uncertainty and workload manipulations. Our results support the wider application of standard evidence accumulation models to applied decision-making settings. PMID:26844369

  10. Evidence accumulation in a complex task: Making choices about concurrent multiattribute stimuli under time pressure.

    PubMed

    Palada, Hector; Neal, Andrew; Vuckovic, Anita; Martin, Russell; Samuels, Kate; Heathcote, Andrew

    2016-03-01

    Evidence accumulation models transform observed choices and associated response times into psychologically meaningful constructs such as the strength of evidence and the degree of caution. Standard versions of these models were developed for rapid (∼1 s) choices about simple stimuli, and have recently been elaborated to some degree to address more complex stimuli and response methods. However, these elaborations can be difficult to use with designs and measurements typically encountered in complex applied settings. We test the applicability of 2 standard accumulation models-the diffusion (Ratcliff & McKoon, 2008) and the linear ballistic accumulation (LBA) (Brown & Heathcote, 2008)-to data from a task representative of many applied situations: the detection of heterogeneous multiattribute targets in a simulated unmanned aerial vehicle (UAV) operator task. Despite responses taking more than 2 s and complications added by realistic features, such as a complex target classification rule, interruptions from a simultaneous UAV navigation task, and time pressured choices about several concurrently present potential targets, these models performed well descriptively. They also provided a coherent psychological explanation of the effects of decision uncertainty and workload manipulations. Our results support the wider application of standard evidence accumulation models to applied decision-making settings.

  11. Anticipation of emotionally aversive visual stimuli activates right insula.

    PubMed

    Simmons, Alan; Matthews, Scott C; Stein, Murray B; Paulus, Martin P

    2004-10-01

    Understanding the neural substrates of anticipation is required for a comprehensive model of the ways in which anxiety influences information processing. While it is apparent that the insula and medial frontal cortex are involved in processing anticipation of physical (i.e., painful) stimuli, their role in processing anticipation of aversive affective stimuli has yet to be determined. Twenty-eight healthy non-phobic volunteers observed aversive affective images (spiders and snakes) that were preceded by an auditory signal. The insula, dorsolateral prefrontal cortex, and parahippocampal gyrus activated during anticipation of aversive affective images. These findings indicate that common neural circuitry is involved in the anticipation of (and, perhaps, the subjective experience of anticipating) aversive affective and noxious physical stimuli. PMID:15371746

  12. Pedophilic brain potential responses to adult erotic stimuli.

    PubMed

    Knott, Verner; Impey, Danielle; Fisher, Derek; Delpero, Emily; Fedoroff, Paul

    2016-02-01

    Cognitive mechanisms associated with the relative lack of sexual interest in adults by pedophiles are poorly understood and may benefit from investigations examining how the brain processes adult erotic stimuli. The current study used event-related brain potentials (ERP) to investigate the time course of the explicit processing of erotic, emotional, and neutral pictures in 22 pedophilic patients and 22 healthy controls. Consistent with previous studies, early latency anterior ERP components were highly selective for erotic pictures. Although the ERPs elicited by emotional stimuli were similar in patients and controls, an early frontal positive (P2) component starting as early as 185 ms was significantly attenuated and slow to onset in pedophilia, and correlated with a clinical measure of cognitive distortions. Failure of rapid attentional capture by erotic stimuli suggests a relative reduction in early processing in pedophilic patients which may be associated with relatively diminished sexual interest in adults. PMID:26683083

  13. Odor of taste stimuli in conditioned "taste" aversion learning.

    PubMed

    Capaldi, Elizabeth D; Hunter, Martin J; Privitera, Gregory J

    2004-12-01

    The present research addresses whether rats can express odor aversions to the odor of taste stimuli. In Experiment 1, saccharin or salt were either mixed in distilled water, so the rats could taste and smell them, or presented on disks attached to the tubes' metal spouts so the rats could only smell them. Aversions were established to taste stimuli under both conditions. The results of Experiment 2 indicate that conditioning was to the odor of the tastes when they were presented on disks in Experiment 1, hence both taste and odor aversions were established by means of "taste" stimuli. Taste aversion learning thus may more properly be termed flavor aversion learning, with flavor referring to both taste and odor components.

  14. Stimuli-Responsive Nanomaterials for Therapeutic Protein Delivery

    PubMed Central

    Lu, Yue; Sun, Wujin; Gu, Zhen

    2014-01-01

    Protein therapeutics have emerged as a significant role in treatment of a broad spectrum of diseases, including cancer, metabolic disorders and autoimmune diseases. The efficacy of protein therapeutics, however, is limited by their instability, immunogenicity and short half-life. In order to overcome these barriers, tremendous efforts have recently been made in developing controlled protein delivery systems. Stimuli-triggered release is an appealing and promising approach for protein delivery and has made protein delivery with both spatiotemporal- and dosage-controlled manners possible. This review surveys recent advances in controlled protein delivery of proteins or peptides using stimuli-responsive nanomaterials. Strategies utilizing both physiological and external stimuli are introduced and discussed. PMID:25151983

  15. Cognitive robotic system for learning of complex visual stimuli

    NASA Astrophysics Data System (ADS)

    Potapov, A. S.; Rozhkov, A. S.

    2013-05-01

    The problem of learning of complex visual stimuli in cognitive robotics is considered. These stimuli should be selected on the base of rules supporting arbitrary comparisons of stimulus features with features of other salient objects (context). New perceptual knowledge representation based on the predicate logic is implemented to express such rules. Computable predicates are provided by low-level vision system. The rules are constructed using genetic algorithms on the base of a set of examples obtained by a robot during consequent trials. Dependence between the number of necessary trials and rule complexity is studied.

  16. Emerging applications of stimuli-responsive polymer materials

    NASA Astrophysics Data System (ADS)

    Stuart, Martien A. Cohen; Huck, Wilhelm T. S.; Genzer, Jan; Müller, Marcus; Ober, Christopher; Stamm, Manfred; Sukhorukov, Gleb B.; Szleifer, Igal; Tsukruk, Vladimir V.; Urban, Marek; Winnik, Françoise; Zauscher, Stefan; Luzinov, Igor; Minko, Sergiy

    2010-02-01

    Responsive polymer materials can adapt to surrounding environments, regulate transport of ions and molecules, change wettability and adhesion of different species on external stimuli, or convert chemical and biochemical signals into optical, electrical, thermal and mechanical signals, and vice versa. These materials are playing an increasingly important part in a diverse range of applications, such as drug delivery, diagnostics, tissue engineering and 'smart' optical systems, as well as biosensors, microelectromechanical systems, coatings and textiles. We review recent advances and challenges in the developments towards applications of stimuli-responsive polymeric materials that are self-assembled from nanostructured building blocks. We also provide a critical outline of emerging developments.

  17. Orienting Toward Face-Like Stimuli in Early Childhood.

    PubMed

    Shah, Punit; Happé, Francesca; Sowden, Sophie; Cook, Richard; Bird, Geoffrey

    2015-01-01

    Newborn infants orient preferentially toward face-like or "protoface" stimuli and recent studies suggest similar reflexive orienting responses in adults. Little is known, however, about the operation of this mechanism in childhood. An attentional-cueing procedure was therefore developed to investigate protoface orienting in early childhood. Consistent with the extant literature, 5- to 6-year-old children (n = 25) exhibited orienting toward face-like stimuli; they responded faster when target location was cued by the appearance of a protoface stimulus than when location was cued by matched control patterns. The potential of this procedure to investigate the development of typical and atypical social perception is discussed. PMID:26435013

  18. Neglect for low luminance contrast stimuli but not for high colour contrast stimuli: a behavioural and electrophysiological case study.

    PubMed

    Doricchi, F; Angelelli, P; De Luca, M; Spinelli, D

    1996-05-31

    We describe a patient with a right hemisphere lesion involving the frontal lobe, the post-central gyrus and the superior parietal lobule. Behavioural testing demonstrated severe left unilateral neglect to low luminance contrast stimuli, but not to high colour contrast stimuli. Evoked potentials to low contrast luminance gratings presented in the left hemifield were not reliable. However, equiluminant coloured gratings presented in the same hemifield evoked reliable electrophysiological responses, although longer in latency than those evoked in the right hemifield. These findings suggest that the patient has severe damage of the high contrast sensitivity magnocellular pathway in the right hemisphere, with minor involvement of the parvocellular pathway.

  19. Standards not that standard.

    PubMed

    Vilanova, Cristina; Tanner, Kristie; Dorado-Morales, Pedro; Villaescusa, Paula; Chugani, Divya; Frías, Alba; Segredo, Ernesto; Molero, Xavier; Fritschi, Marco; Morales, Lucas; Ramón, Daniel; Peña, Carlos; Peretó, Juli; Porcar, Manuel

    2015-01-01

    There is a general assent on the key role of standards in Synthetic Biology. In two consecutive letters to this journal, suggestions on the assembly methods for the Registry of standard biological parts have been described. We fully agree with those authors on the need of a more flexible building strategy and we highlight in the present work two major functional challenges standardization efforts have to deal with: the need of both universal and orthogonal behaviors. We provide experimental data that clearly indicate that such engineering requirements should not be taken for granted in Synthetic Biology. PMID:26435739

  20. Updating Positive and Negative Stimuli in Working Memory in Depression

    ERIC Educational Resources Information Center

    Levens, Sara M.; Gotlib, Ian H.

    2010-01-01

    Difficulties in the ability to update stimuli in working memory (WM) may underlie the problems with regulating emotions that lead to the development and perpetuation of mood disorders such as depression. To examine the ability to update affective material in WM, the authors had diagnosed depressed and never-disordered control participants perform…

  1. Infants' Preferential Attention to Sung and Spoken Stimuli

    ERIC Educational Resources Information Center

    Costa-Giomi, Eugenia; Ilari, Beatriz

    2014-01-01

    Caregivers and early childhood teachers all over the world use singing and speech to elicit and maintain infants' attention. Research comparing infants' preferential attention to music and speech is inconclusive regarding their responses to these two types of auditory stimuli, with one study showing a music bias and another one…

  2. Submillisecond unmasked subliminal visual stimuli evoke electrical brain responses.

    PubMed

    Sperdin, Holger F; Spierer, Lucas; Becker, Robert; Michel, Christoph M; Landis, Theodor

    2015-04-01

    Subliminal perception is strongly associated to the processing of meaningful or emotional information and has mostly been studied using visual masking. In this study, we used high density 256-channel EEG coupled with an liquid crystal display (LCD) tachistoscope to characterize the spatio-temporal dynamics of the brain response to visual checkerboard stimuli (Experiment 1) or blank stimuli (Experiment 2) presented without a mask for 1 ms (visible), 500 µs (partially visible), and 250 µs (subliminal) by applying time-wise, assumption-free nonparametric randomization statistics on the strength and on the topography of high-density scalp-recorded electric field. Stimulus visibility was assessed in a third separate behavioral experiment. Results revealed that unmasked checkerboards presented subliminally for 250 µs evoked weak but detectable visual evoked potential (VEP) responses. When the checkerboards were replaced by blank stimuli, there was no evidence for the presence of an evoked response anymore. Furthermore, the checkerboard VEPs were modulated topographically between 243 and 296 ms post-stimulus onset as a function of stimulus duration, indicative of the engagement of distinct configuration of active brain networks. A distributed electrical source analysis localized this modulation within the right superior parietal lobule near the precuneus. These results show the presence of a brain response to submillisecond unmasked subliminal visual stimuli independently of their emotional saliency or meaningfulness and opens an avenue for new investigations of subliminal stimulation without using visual masking. PMID:25487054

  3. Impact prediction by looming visual stimuli enhances tactile detection.

    PubMed

    Cléry, Justine; Guipponi, Olivier; Odouard, Soline; Wardak, Claire; Ben Hamed, Suliann

    2015-03-11

    From an ecological point of view, approaching objects are potentially more harmful than receding objects. A predator, a dominant conspecific, or a mere branch coming up at high speed can all be dangerous if one does not detect them and produce the appropriate escape behavior fast enough. And indeed, looming stimuli trigger stereotyped defensive responses in both monkeys and human infants. However, while the heteromodal somatosensory consequences of visual looming stimuli can be fully predicted by their spatiotemporal dynamics, few studies if any have explored whether visual stimuli looming toward the face predictively enhance heteromodal tactile sensitivity around the expected time of impact and at its expected location on the body. In the present study, we report that, in addition to triggering a defensive motor repertoire, looming stimuli toward the face provide the nervous system with predictive cues that enhance tactile sensitivity on the face. Specifically, we describe an enhancement of tactile processes at the expected time and location of impact of the stimulus on the face. We additionally show that a looming stimulus that brushes past the face also enhances tactile sensitivity on the nearby cheek, suggesting that the space close to the face is incorporated into the subjects' body schema. We propose that this cross-modal predictive facilitation involves multisensory convergence areas subserving the representation of a peripersonal space and a safety boundary of self.

  4. Stimuli-Responsive Nanoparticles for siRNA Delivery.

    PubMed

    Eloy, Josimar O; Petrilli, Raquel; Lopez, Renata F V; Lee, Robert J

    2015-01-01

    Nanoparticles have been extensively employed to deliver many drugs, including siRNA, for the treatment of a variety of diseases, particularly cancer. Lately, there has been a great deal of effort to design nanoparticles with materials that are able to respond to intrinsic or extrinsic stimuli for "on demand" delivery of siRNA. These nanoparticles are able to trigger siRNA release upon different stimuli, such as a pH decrease, redox gradient, enzyme, light, magnetic field, temperature, ultrasound or electric current. Frequently, the stimuli cause the nanoparticles to undergo protonation, hydrolytic breakdown or phase transition for triggered release of siRNA, resulting in decreased side effects and better therapeutic outcome. While studies have demonstrated efficient in vitro and in vivo delivery, these "smart" nanoparticles have not yet reached the clinic. In this review, we address different classes of nanoparticles, such as polyplexes, lipoplexes, liposomes, polymeric micelles, polymeric, lipid and inorganic nanoparticles, that are able to respond to specific stimuli for siRNA triggered-release, emphasizing their application and discussing the latest advances. PMID:26323434

  5. Reward contexts extend dopamine signals to unrewarded stimuli.

    PubMed

    Kobayashi, Shunsuke; Schultz, Wolfram

    2014-01-01

    Basic tenets of sensory processing emphasize the importance of accurate identification and discrimination of environmental objects [1]. Although this principle holds also for reward, the crucial acquisition of reward for survival would be aided by the capacity to detect objects whose rewarding properties may not be immediately apparent. Animal learning theory conceptualizes how unrewarded stimuli induce behavioral reactions in rewarded contexts due to pseudoconditioning and higher-order context conditioning [2-6]. We hypothesized that the underlying mechanisms may involve context-sensitive reward neurons. We studied short-latency activations of dopamine neurons to unrewarded, physically salient stimuli while systematically changing reward context. Dopamine neurons showed substantial activations to unrewarded stimuli and their conditioned stimuli in highly rewarded contexts. The activations decreased and often disappeared entirely with stepwise separation from rewarded contexts. The influence of reward context suggests that dopamine neurons respond to real and potential reward. The influence of reward context is compatible with the reward nature of phasic dopamine responses. The responses may facilitate rapid, default initiation of behavioral reactions in environments usually containing reward. Agents would encounter more and miss less reward, resulting in survival advantage and enhanced evolutionary fitness.

  6. Tagging Multiple Emotional Stimuli: Negative Valence Has Little Benefit

    ERIC Educational Resources Information Center

    Watson, Derrick G.; Blagrove, Elisabeth

    2012-01-01

    Six experiments examined the influence of emotional valence on the tagging and enumeration of multiple targets. Experiments 1, 5 and 6 found that there was no difference in the efficiency of tagging/enumerating multiple negative or positive stimuli. Experiment 2 showed that, when neutral-expression face distractors were present, enumerating…

  7. Slowed response to peripheral visual stimuli during strenuous exercise.

    PubMed

    Ando, Soichi; Komiyama, Takaaki; Kokubu, Masahiro; Sudo, Mizuki; Kiyonaga, Akira; Tanaka, Hiroaki; Higaki, Yasuki

    2016-07-01

    Recently, we proposed that strenuous exercise impairs peripheral visual perception because visual responses to peripheral visual stimuli were slowed during strenuous exercise. However, this proposal was challenged because strenuous exercise is also likely to affect the brain network underlying motor responses. The purpose of the current study was to resolve this issue. Fourteen participants performed a visual reaction-time (RT) task at rest and while exercising at 50% (moderate) and 75% (strenuous) peak oxygen uptake. Visual stimuli were randomly presented at different distances from fixation in two task conditions: the Central condition (2° or 5° from fixation) and the Peripheral condition (30° or 50° from fixation). We defined premotor time as the time between stimulus onset and the motor response, as determined using electromyographic recordings. In the Central condition, premotor time did not change during moderate (167±19ms) and strenuous (168±24ms) exercise from that at rest (164±17ms). In the Peripheral condition, premotor time significantly increased during moderate (181±18ms, P<0.05) and strenuous exercise (189±23ms, P<0.001) from that at rest (173±17ms). These results suggest that increases in Premotor Time to the peripheral visual stimuli did not result from an impaired motor-response network, but rather from impaired peripheral visual perception. We conclude that slowed response to peripheral visual stimuli during strenuous exercise primarily results from impaired visual perception of the periphery. PMID:27080081

  8. Stimuli-responsive polymersomes for programmed drug delivery.

    PubMed

    Meng, Fenghua; Zhong, Zhiyuan; Feijen, Jan

    2009-02-01

    In the past decade, polymersomes (also referred to as polymeric vesicles) have attracted rapidly growing interest based on their intriguing aggregation phenomena, cell and virus-mimicking dimensions and functions, as well as tremendous potential applications in medicine, pharmacy, and biotechnology. Unlike liposomes self-assembled from low molecular weight lipids, polymersomes are in general prepared from macromolecular amphiphiles of various architectures including amphiphilic diblock, triblock, graft and dendritic copolymers. Polymersomes exhibit very unique features highlighted with high stability, tunable membrane properties, versatility, and capacity of transporting hydrophilic as well as hydrophobic species such as anticancer drugs, genes, proteins, and diagnostic probes. Recently, much effort has been directed to the development of intelligent polymersomes that respond to internal or external stimuli, in particular, pH, temperature, redox potential, light, magnetic field, and ultrasound, either reversibly or nonreversibly. Stimuli-sensitive polymersomes have emerged as novel programmable delivery systems in which the release of the encapsulated contents can be readily modulated by the stimulus. The stimuli-responsive release may result in significantly enhanced therapeutic efficacy and minimized possible side effects. It is also feasible to form and disassemble polymersomes in water simply by applying an appropriate stimulus. In this article, recent advances in stimuli-sensitive polymersomes have been reviewed, and perspectives on future developments have been discussed.

  9. The Effect of Being Able to Control Aversive Stimuli.

    ERIC Educational Resources Information Center

    Geer, James H.

    Research was conducted to investigate the phenomena associated with an individual's having perceived control or actual control over aversive stimuli. In all, 10 studies were conducted, 7 of which were directly relevant to investigating variables affecting perceived or actual control, and 3 being "spin-off" experiments. The seven studies tested the…

  10. Impaired Prioritization of Novel Onset Stimuli in Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Keehn, Brandon; Joseph, Robert M.

    2008-01-01

    Background: Deficiency in the adaptive allocation of attention to relevant environmental stimuli is an associated feature of autism spectrum disorder (ASD). Recent evidence suggests that individuals with ASD may be specifically impaired in attentional prioritization of novel onsets. Method: We investigated modulation of attention by novel onset…

  11. Gradient Shifts with Naturally Occurring Human Face Stimuli

    ERIC Educational Resources Information Center

    Derenne, Adam; Breitstein, R. Michael

    2006-01-01

    The present research examined stimulus generalization and gradient shifts on a dimension involving human faces. Twenty undergraduates were instructed to examine the proportion of the total face length that lay between the tip of the nose and the end of the chin. The face stimuli were images of actual people shown on a computer screen; no face was…

  12. Superior Detection of Threat-Relevant Stimuli in Infancy

    ERIC Educational Resources Information Center

    LoBue, Vanessa; DeLoache, Judy S.

    2010-01-01

    The ability to quickly detect potential threat is an important survival mechanism for humans and other animals. Past research has established that adults have an attentional bias for the detection of threat-relevant stimuli, including snakes and spiders as well as angry human faces. Recent studies have documented that preschool children also…

  13. Alliesthesia to food cues: heterogeneity across stimuli and sensory modalities.

    PubMed

    Jiang, Tao; Soussignan, Robert; Rigaud, Daniel; Martin, Sylviane; Royet, Jean-Pierre; Brondel, Laurent; Schaal, Benoist

    2008-10-20

    Negative alliesthesia to olfactory and visual stimuli was assessed in 29 normal-weight women who, on alternate days, were either fasting or in a postprandial state after an ad libitum lunch. The participants were alternatively exposed to food and non-food pictures and odorants, and then rated for their hedonic appreciation (liking) and their desire to ingest (wanting) the evoked foods. While negative alliesthesia was observed only for food stimuli, it did not equally affect all food categories in either sensory modality. The stimuli representing foods eaten in typical local main dishes or having high energy density (e.g., pizza, bacon, beef, cheese) evoked clear negative alliesthesia, whereas this was not the case for those less consumed within a customary meal or associated with desserts (i.e., fruits). Furthermore, the visual food stimuli triggered a more negative shift in liking than did the food odours. Finally, the shift in wanting between pre- and post-meal state was more important than the shift in liking. These results suggest that alliesthesia may be influenced by both metabolic and non-metabolic factors.

  14. A Study of the Affective Responses Elicited by Occupational Stimuli

    ERIC Educational Resources Information Center

    Schoon, Craig G.

    1976-01-01

    The semantic differential was used to assess the properties of affect elicited by occupational stimuli. Vocationally committed men studying medicine, business, and engineering responded to a semantic differential containing occupational concepts. Results show a semantic space for all three groups composed of three orthogonal dimensions of affect…

  15. Joint Control and the Selection of Stimuli from Their Description

    ERIC Educational Resources Information Center

    Lowenkron, Barry

    2006-01-01

    This research examined the role the two constituents of joint control, the tact and the echoic, play in producing accurate selections of novel stimuli in response to their spoken descriptions. Experiment 1 examined the role of tacts. In response to unfamiliar spoken descriptions, children learned to select from among six successively presented…

  16. Probability of Equivalence Formation: Familiar Stimuli and Training Sequence

    ERIC Educational Resources Information Center

    Arntzen, Erik

    2004-01-01

    The present study was conducted to show how responding in accord with equivalence relations changes as a function of position of familiar stimuli, pictures, and with the use of nonsense syllables in an MTO-training structure. Fifty college students were tested for responding in accord with equivalence in an AB, CB, DB, and EB training structure.…

  17. Reliable activation to novel stimuli predicts higher fluid intelligence.

    PubMed

    Euler, Matthew J; Weisend, Michael P; Jung, Rex E; Thoma, Robert J; Yeo, Ronald A

    2015-07-01

    The ability to reliably respond to stimuli could be an important biological determinant of differences in fluid intelligence (Gf). However, most electrophysiological studies of Gf employ event-related potential (ERP) measures that average brain activity over trials, and hence have limited power to quantify neural variability. Time-frequency analyses can capture cross-trial variation in the phase of neural activity, and thus can help address the importance of neural reliability to differences in Gf. This study recruited a community sample of healthy adults and measured inter-trial phase clustering (ITPC), total spectral power, and ERP amplitudes elicited by Repeated and Novel non-target stimuli during two visual oddball tasks. Condition effects, relations among the EEG measures, and relations with Gf were assessed. Early visual responses to Repeated stimuli elicited higher ITPC, yet only ITPC elicited by Novel stimuli was associated with Gf. Analyses of spectral power further highlighted the contribution of phase consistency to the findings. The link between Gf and reliable responding to changing inputs suggests an important role for flexible resource allocation in fluid intellectual skills.

  18. Delivery of continuously-varying stimuli using channelrhodopsin-2

    PubMed Central

    Tchumatchenko, Tatjana; Newman, Jonathan P.; Fong, Ming-fai; Potter, Steve M.

    2013-01-01

    To study sensory processing, stimuli are delivered to the sensory organs of animals and evoked neural activity is recorded downstream. However, noise and uncontrolled modulatory input can interfere with repeatable delivery of sensory stimuli to higher brain regions. Here we show how channelrhodopsin-2 (ChR2) can be used to deliver continuous, subthreshold, time-varying currents to neurons at any point along the sensory-motor pathway. To do this, we first deduce the frequency response function of ChR2 using a Markov model of channel kinetics. We then confirm ChR2's frequency response characteristics using continuously-varying optical stimulation of neurons that express one of three ChR2 variants. We find that wild-type ChR2 and the E123T/H134R mutant (“ChETA”) can pass continuously-varying subthreshold stimuli with frequencies up to ~70 Hz. Additionally, we find that wild-type ChR2 exhibits a strong resonance at ~6–10 Hz. Together, these results indicate that ChR2-derived optogenetic tools are useful for delivering highly repeatable artificial stimuli that mimic in vivo synaptic bombardment. PMID:24367294

  19. Positive mood broadens visual attention to positive stimuli

    PubMed Central

    Wadlinger, Heather A.; Isaacowitz, Derek M.

    2010-01-01

    In an attempt to investigate the impact of positive emotions on visual attention within the context of Fredrickson's (1998) broaden-and-build model, eye tracking was used in two studies to measure visual attentional preferences of college students (n=58, n=26) to emotional pictures. Half of each sample experienced induced positive mood immediately before viewing slides of three similarly-valenced images, in varying central-peripheral arrays. Attentional breadth was determined by measuring the percentage viewing time to peripheral images as well as by the number of visual saccades participants made per slide. Consistent with Fredrickson's theory, the first study showed that individuals induced into positive mood fixated more on peripheral stimuli than did control participants; however, this only held true for highly-valenced positive stimuli. Participants under induced positive mood also made more frequent saccades for slides of neutral and positive valence. A second study showed that these effects were not simply due to differences in emotional arousal between stimuli. Selective attentional broadening to positive stimuli may act both to facilitate later building of resources as well as to maintain current positive affective states. PMID:20431711

  20. Developmental Complexity of the Stimuli Included in Mispronunciation Detection Tasks

    ERIC Educational Resources Information Center

    McNeill, Brigid C.; Hesketh, Anne

    2010-01-01

    Background: Phonological representations are important for speech and literacy development. Mispronunciation detection tasks have been proposed as an appropriate measure of phonological representations for children with speech disorder. There has been limited analysis, however, of the developmental complexity of task stimuli. Further, the tasks…

  1. Auditory Long Latency Responses to Tonal and Speech Stimuli

    ERIC Educational Resources Information Center

    Swink, Shannon; Stuart, Andrew

    2012-01-01

    Purpose: The effects of type of stimuli (i.e., nonspeech vs. speech), speech (i.e., natural vs. synthetic), gender of speaker and listener, speaker (i.e., self vs. other), and frequency alteration in self-produced speech on the late auditory cortical evoked potential were examined. Method: Young adult men (n = 15) and women (n = 15), all with…

  2. Differences in Sensorimotor Processing of Visual and Proprioceptive Stimuli

    ERIC Educational Resources Information Center

    Kamen, Gary and Morris, Harold H.

    1988-01-01

    A paradox in studying sensory perception is that people often attend to a stimulus which provides the least optimal information. Usually, this is a visual stimulus. The study sought to lessen this reliance on vision by training subjects to respond to proprioceptive stimuli. Results are discussed. (Author/JL)

  3. Stimuli-sensitive nanopreparations for combination cancer therapy.

    PubMed

    Jhaveri, Aditi; Deshpande, Pranali; Torchilin, Vladimir

    2014-09-28

    Nanocarriers have revolutionized drug delivery practices over the past couple of decades, primarily due to the advances in materials chemistry, nanotechnology and nanomedicine. This in turn, has spurred the development of a number of novel nanocarrier-based platforms and treatment strategies for cancer. It is now clear that to manage a disease as complex as cancer, a single or stand-alone treatment strategy may not suffice. Present day drug delivery strategies progressively lean towards "multi-pronged" combination approaches to make cancer treatments more effective. To that end, nanocarriers which simultaneously incorporate multiple drugs that affect different pathways and act through different mechanisms, or combinations of drugs with biological therapeutics like genes, antibodies, proteins or siRNAs have been the focus of recent active research. Furthermore, nanocarriers which respond to a variety of intrinsic cues afforded by the tumor microenvironment like low pH, elevated redox potential, over-expressed enzymes and hyperthermia as well as to externally applied stimuli such as magnetic field, ultrasound or light have been developed to trigger site-specific drug release. In this review, we focus specifically on nanocarriers that simultaneously exhibit stimuli-sensitivity and incorporate various combinations of conventional small molecule chemotherapeutic agents and biologics. We provide an overview of the different internal and external stimuli most relevant to cancer, and discuss selected examples of stimuli-sensitive combination nanopreparations from the recent literature with respect to each stimulus. Finally, we discuss multifunctional stimuli-sensitive nanopreparations which incorporate various combinations of drugs, biologics and targeting ligands within a single carrier that form so-called "smart" nanopreparations. PMID:24818767

  4. Cortical responses from adults and infants to complex visual stimuli.

    PubMed

    Schulman-Galambos, C; Galambos, R

    1978-10-01

    Event-related potentials (ERPs) time-locked to the onset of visual stimuli were extracted from the EEG of normal adult (N = 16) and infant (N = 23) subjects. Subjects were not required to make any response. Stimuli delivered to the adults were 150 msec exposures of 2 sets of colored slides projected in 4 blocks, 2 in focus and 2 out of focus. Infants received 2-sec exposures of slides showing people, colored drawings or scenes from Disneyland, as well as 2-sec illuminations of the experimenter as she played a game or of a TV screen the baby was watching. The adult ERPs showed 6 waves (N1 through P4) in the 140--600-msec range; this included a positive wave at around 350 msec that was large when the stimuli were focused and smaller when they were not. The waves in the 150--200-msec range, by contrast, steadily dropped in amplitude as the experiment progressed. The infant ERPs differed greatly from the adult ones in morphology, usually showing a positive (latency about 200 msec)--negative(5--600msec)--positive(1000msec) sequence. This ERP appeared in all the stimulus conditions; its presence or absence, furthermore, was correlated with whether or not the baby seemed interested in the stimuli. Four infants failed to produce these ERPs; an independent measure of attention to the stimuli, heart rate deceleration, was demonstrated in two of them. An electrode placed beneath the eye to monitor eye movements yielded ERPs closely resembling those derived from the scalp in most subjects; reasons are given for assigning this response to activity in the brain, probably at the frontal pole. This study appears to be one of the first to search for cognitive 'late waves' in a no-task situation. The results suggest that further work with such task-free paradigms may yield additional useful techniques for studying the ERP.

  5. Intermodal transfer in temporal discrimination. [of visual and acoustic stimuli duration

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Stutz, R. M.; Vassolo, P. A.

    1975-01-01

    This study determined if training for accuracy in temporal discrimination would transfer across sensory modalities. A fractionation method was used in which subjects bisected the durations of acoustic and visual signals at three standard intervals (6, 12, and 18 sec). Absolute error was the performance index. Half of the subjects were trained with acoustic stimuli and then tested in vision; the remainder were trained in vision and tested in audition. Similar negatively accelerated acquisition functions were noted for both modalities. Positive intermodal transfer, characterized by symmetry across modalities, was obtained at all standard durations. The results were considered to provide support for the notion that a common mechanism underlies temporal discriminations in different sensory systems.

  6. Spatiotemporal dynamics of random stimuli account for trial-to-trial variability in perceptual decision making

    PubMed Central

    Park, Hame; Lueckmann, Jan-Matthis; von Kriegstein, Katharina; Bitzer, Sebastian; Kiebel, Stefan J.

    2016-01-01

    Decisions in everyday life are prone to error. Standard models typically assume that errors during perceptual decisions are due to noise. However, it is unclear how noise in the sensory input affects the decision. Here we show that there are experimental tasks for which one can analyse the exact spatio-temporal details of a dynamic sensory noise and better understand variability in human perceptual decisions. Using a new experimental visual tracking task and a novel Bayesian decision making model, we found that the spatio-temporal noise fluctuations in the input of single trials explain a significant part of the observed responses. Our results show that modelling the precise internal representations of human participants helps predict when perceptual decisions go wrong. Furthermore, by modelling precisely the stimuli at the single-trial level, we were able to identify the underlying mechanism of perceptual decision making in more detail than standard models. PMID:26752272

  7. Sexual preference for child and aggressive stimuli: comparison of rapists and child molesters using auditory and visual stimuli.

    PubMed

    Miner, M H; West, M A; Day, D M

    1995-06-01

    154 Ss were tested using penile plethysmography as part of intake into a voluntary inpatient sex offender treatment program. The testing protocol included slide stimuli of nude males and females in four age categories ranging from age 1 to adult; audiotaped descriptions of sexual activity with children of both genders which included fondling, sexual contact with no resistance, coercive sexual contact, sexual assault, nonsexual assault, and consensual sexual contact with an adult; videotaped depictions of rape of an adult woman, nonsexual assault of an adult woman and consensual sexual involvement with an adult woman, and audiotaped descriptions that paralleled the videotapes. The results indicated that child molesters (male victim) show a decidedly more offense related arousal profile than either child molesters (female victim) or rapists, and that the profiles of child molesters (female victim) and rapists are remarkably similar, although statistically significantly different from each other. Rapists respond significantly more to rape and nonsexual assault than either of the two child molester groups, with child molesters with female victims responding more than those with male victims. In all three groups, the highest level of noncoercive adult responding was to women, with differences among offense groups present for visual stimuli, but not in response to auditory stimuli. Overall, the patterns of results are similar whether they are based on composites across stimulus modality or on the individual stimuli.

  8. Sexual preference for child and aggressive stimuli: comparison of rapists and child molesters using auditory and visual stimuli.

    PubMed

    Miner, M H; West, M A; Day, D M

    1995-06-01

    154 Ss were tested using penile plethysmography as part of intake into a voluntary inpatient sex offender treatment program. The testing protocol included slide stimuli of nude males and females in four age categories ranging from age 1 to adult; audiotaped descriptions of sexual activity with children of both genders which included fondling, sexual contact with no resistance, coercive sexual contact, sexual assault, nonsexual assault, and consensual sexual contact with an adult; videotaped depictions of rape of an adult woman, nonsexual assault of an adult woman and consensual sexual involvement with an adult woman, and audiotaped descriptions that paralleled the videotapes. The results indicated that child molesters (male victim) show a decidedly more offense related arousal profile than either child molesters (female victim) or rapists, and that the profiles of child molesters (female victim) and rapists are remarkably similar, although statistically significantly different from each other. Rapists respond significantly more to rape and nonsexual assault than either of the two child molester groups, with child molesters with female victims responding more than those with male victims. In all three groups, the highest level of noncoercive adult responding was to women, with differences among offense groups present for visual stimuli, but not in response to auditory stimuli. Overall, the patterns of results are similar whether they are based on composites across stimulus modality or on the individual stimuli. PMID:7598675

  9. Connecting massive galaxies to dark matter haloes in BOSS - I. Is galaxy colour a stochastic process in high-mass haloes?

    NASA Astrophysics Data System (ADS)

    Saito, Shun; Leauthaud, Alexie; Hearin, Andrew P.; Bundy, Kevin; Zentner, Andrew R.; Behroozi, Peter S.; Reid, Beth A.; Sinha, Manodeep; Coupon, Jean; Tinker, Jeremy L.; White, Martin; Schneider, Donald P.

    2016-08-01

    We use subhalo abundance matching (SHAM) to model the stellar mass function (SMF) and clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) `CMASS' sample at z ˜ 0.5. We introduce a novel method which accounts for the stellar mass incompleteness of CMASS as a function of redshift, and produce CMASS mock catalogues which include selection effects, reproduce the overall SMF, the projected two-point correlation function wp, the CMASS dn/dz, and are made publicly available. We study the effects of assembly bias above collapse mass in the context of `age matching' and show that these effects are markedly different compared to the ones explored by Hearin et al. at lower stellar masses. We construct two models, one in which galaxy colour is stochastic (`AbM' model) as well as a model which contains assembly bias effects (`AgM' model). By confronting the redshift dependent clustering of CMASS with the predictions from our model, we argue that that galaxy colours are not a stochastic process in high-mass haloes. Our results suggest that the colours of galaxies in high-mass haloes are determined by other halo properties besides halo peak velocity and that assembly bias effects play an important role in determining the clustering properties of this sample.

  10. Validation of an automated punctate mechanical stimuli delivery system designed for fMRI studies in rodents.

    PubMed

    Governo, Ricardo Jose Moylan; Prior, Malcolm John William; Morris, Peter Gordon; Marsden, Charles Alexander; Chapman, Victoria

    2007-06-15

    Functional magnetic resonance imaging (fMRI) is increasingly being used for animal studies studying the transmission of nociceptive information. Application of noxious mechanical stimuli is widely used for animal and human assessment of pain processing. Any accessory hardware used in animal imaging studies must, however, be sufficiently small to fit in the magnet bore diameter and be non-magnetic. We have developed a system that can apply mechanical stimuli simultaneously with fMRI. This system consists of a standardized instrument to deliver mechanical stimuli (VonFrey monofilament) and a gas-pressured mechanical transducer. These components were integrated with a computer console that controlled the period of stimuli to match acquisition scans. Preliminary experiments demonstrated that the force-stimulus transducer did not influence MRI signal to noise ratio. Mechanical stimulation of the hindpaw significantly increased blood oxygen level dependent (BOLD) signal intensity in several midbrain regions involved in the processing of nociceptive information in the rat (p<0.001, uncorrected for multiple comparisons). This system can be applied to both animal and human imaging studies and has a wide range of applications for studies of nociceptive processing. PMID:17368787

  11. Capsicum--production, technology, chemistry, and quality. Part III. Chemistry of the color, aroma, and pungency stimuli.

    PubMed

    Govindarajan, V S

    1986-01-01

    The spice capsicum, the fruits of the genus Capsicum (Family Solanaceae), is a very popular food additive in many parts of the world, valued for the important sensory attributes of color, pungency, and aroma. A large number of varieties are widely cultivated and traded. The characteristic carotenoids of the bright red paprika and cayenne-type chillies, the high character impact aroma stimuli, the methoxy pyrazine of green bell capsicum, the esters of ripe tabasco and the highly potent pungency stimuli, and the capsaicinoids of African and other Asian varieties of chillies, have been of great interest to chemists and biochemists. Research workers in other disciplines such as genetics and breeding, agriculture, and technology have been interested in this spice to develop new varieties with combinations of different optimal levels of the stimuli for the sensory attributes and to maximize production of storable products for specific end uses. Physiologists have been intensely studying the action of the highly potent pungency stimuli and social psychologists the curious aspect of growing acceptance and preference for the initially unacceptable pungency sensation. In the sequential review of all these aspects of the fruit spice Capsicum, the earlier two parts covered history, botany, cultivation and primary processing, and processed products, standards, world production, and trade. In Part III, the chemistry, the compositional variations, synthesis and biosynthesis of the functional components, the carotenoids, the volatiles, and the capsaicinoids are comprehensively reviewed. PMID:3527565

  12. Stimuli-responsive supramolecular polymers in aqueous solution.

    PubMed

    Ma, Xiang; Tian, He

    2014-07-15

    CONSPECTUS: Aiming to construct various novel supramolecular polymeric structures in aqueous solution beyond small supramolecular self-assembly molecules and develop functional supramolecular polymeric materials, research interest on functional supramolecular polymers has been prevailing in recent years. Supramolecular polymers are formed by bridging monomers or components together via highly directional noncovalent interactions such as hydrogen bonding, hydrophobic interaction, π-π interaction, metal-ligand coordination, electrostatic interaction, and so forth. They can be easily functionalized by employing diverse building components with specific functions besides the traditional polymeric properties, a number of which are responsive to such external stimuli as pH variance, photoirradiation, chemically or electrochemically redox with the controllable conformation or construction switching, polymerization building and rebuilding, and function adjustment reversibly owing to the reversibility of noncovalent interactions. Supramolecular polymers are "soft matters" and can be functionalized with specific properties such as morphology adjustment, controllable luminescence, shape memory, self-healing, and so forth. Supramolecular polymers constructed based on macrocycle recognition and interlocked structures represent one typical branch of the supramolecular polymer family. Cyclodextrin (CD), cucurbituril (CB), and hydrophilic calixarene derivatives are usually employed to construct hydrophilic supramolecular polymers in aqueous solution. Stimuli-responsive hydrophilic supramolecular polymers, constructed in aqueous solution particularly, can be promising candidates for mimicking biocompatible or vital functional materials. This Account mainly focuses on the recent stimuli-responsive supramolecular polymers based on the host-guest interaction in aqueous solution. We describe the hydrophilic supramolecular polymers constructed via hydrophobic effects, electrostatic

  13. Multifunctional, stimuli-sensitive nanoparticulate systems for drug delivery

    PubMed Central

    Torchilin, Vladimir P.

    2015-01-01

    The use of nanoparticulate pharmaceutical drug delivery systems (NDDSs) to enhance the in vivo effectiveness of drugs is now well established. The development of multifunctional and stimulus-sensitive NDDSs is an active area of current research. Such NDDSs can have long circulation times, target the site of the disease and enhance the intracellular delivery of a drug. This type of NDDS can also respond to local stimuli that are characteristic of the pathological site by, for example, releasing an entrapped drug or shedding a protective coating, thus facilitating the interaction between drug-loaded nanocarriers and target cells or tissues. In addition, imaging contrast moieties can be attached to these carriers to track their real-time biodistribution and accumulation in target cells or tissues. Here, I highlight recent developments with multifunctional and stimuli-sensitive NDDSs and their therapeutic potential for diseases including cancer, cardiovascular diseases and infectious diseases. PMID:25287120

  14. Joint attention for stimuli on the hands: ownership matters

    PubMed Central

    Taylor, J. E. T.; Pratt, Jay; Witt, Jessica K.

    2015-01-01

    The visual system treats the space near the hands with unique, action-related priorities. For example, attention orients slowly to stimuli on the hands (Taylor and Witt, 2014). In this article, we asked whether jointly attended hands are attended in the same way. Specifically, we examined whether ownership over the hand mattered: do we attend to our hands and the hands of others in the same way? Pairs of participants performed a spatial cueing task with stimuli that could be projected onto one partner’s hands or on a control surface. Results show delayed orienting of attention to targets appearing on the hands, but only for the owner of the hands. For an observer, others’ hands are like any other surface. This result emphasizes the importance of ownership for hand-based effects on vision, and in doing so, is inconsistent with some expectations of the joint action literature. PMID:25983713

  15. On wildebeests and humans: the preferential detection of negative stimuli.

    PubMed

    Dijksterhuis, Ap; Aarts, Henk

    2003-01-01

    On the basis of a functional perspective, we hypothesized that negative stimuli are detected faster than positive stimuli. In Experiment 1, participants were subliminally presented with positive and negative words or with no words at all. After each presentation, participants were asked whether they had seen a word. They detected negative words more accurately than positive words. In Experiment 2, participants were subliminally presented with negative or positive words. After each presentation, they were asked whether the presented word was positive or negative. Negative words were correctly categorized more often than positive words. Experiment 3 showed that although participants correctly categorized negative words more often than positive words. they could not guess the meaning of the words better than would be expected by chance. The results are discussed against the background of recent findings on basic affective processes. PMID:12564748

  16. Stimuli-responsive nanoparticles from ionic cellulose derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Yonggui; Heinze, Thomas; Zhang, Kai

    2015-12-01

    Stimuli-responsive nanoparticles (NPs) based on sustainable polymeric feedstock still need more exploration in comparison with NPs based on synthetic polymers. In this report, stimuli-responsive NPs from novel ionic cellulose derivatives were prepared via a facile nanoprecipitation. Cellulose 10-undecenoyl ester (CUE) with a degree of substitution (DS) of 3 was synthesized by esterification of cellulose with 10-undecenoyl chloride. Then, CUE was modified by photo-induced thiol-ene reactions, in order to obtain organo-soluble ionic cellulose derivatives with DSs of ~3, namely cellulose 11-((3-carboxyl)ethylthio)undecanoate (CUE-MPA), cellulose 11-((2-aminoethyl)thio)undecanoate (CUE-CA), cellulose 11-(2-(2-(diethylamino)ethyl)thio)undecanoate (CUE-DEAET) and cellulose 11-(2-(2-(dimethylamino)ethyl)thio)undecanoate (CUE-DMAET). CUE-MPA could be transformed into NPs with average diameters in the range of 80-330 nm, but these NPs did not show particular stimuli-responsive properties. Moreover, the dropping technique resulted in smaller NPs than a dialysis technique. Stable NPs with average diameters in the range of 90-180 nm showing pH-responsive and switchable sizes were obtained from CUE-DEAET and CUE-DMAET possessing tertiary amines using nanoprecipitation. Thus, altering the terminal functional groups will be a new approach to prepare stimuli-responsive cellulose-derived polymeric NPs.Stimuli-responsive nanoparticles (NPs) based on sustainable polymeric feedstock still need more exploration in comparison with NPs based on synthetic polymers. In this report, stimuli-responsive NPs from novel ionic cellulose derivatives were prepared via a facile nanoprecipitation. Cellulose 10-undecenoyl ester (CUE) with a degree of substitution (DS) of 3 was synthesized by esterification of cellulose with 10-undecenoyl chloride. Then, CUE was modified by photo-induced thiol-ene reactions, in order to obtain organo-soluble ionic cellulose derivatives with DSs of ~3, namely cellulose

  17. Multifunctional, stimuli-sensitive nanoparticulate systems for drug delivery.

    PubMed

    Torchilin, Vladimir P

    2014-11-01

    The use of nanoparticulate pharmaceutical drug delivery systems (NDDSs) to enhance the in vivo effectiveness of drugs is now well established. The development of multifunctional and stimulus-sensitive NDDSs is an active area of current research. Such NDDSs can have long circulation times, target the site of the disease and enhance the intracellular delivery of a drug. This type of NDDS can also respond to local stimuli that are characteristic of the pathological site by, for example, releasing an entrapped drug or shedding a protective coating, thus facilitating the interaction between drug-loaded nanocarriers and target cells or tissues. In addition, imaging contrast moieties can be attached to these carriers to track their real-time biodistribution and accumulation in target cells or tissues. Here, I highlight recent developments with multifunctional and stimuli-sensitive NDDSs and their therapeutic potential for diseases including cancer, cardiovascular diseases and infectious diseases. PMID:25287120

  18. The automatic orienting of attention to goal-relevant stimuli.

    PubMed

    Vogt, Julia; De Houwer, Jan; Moors, Agnes; Van Damme, Stefaan; Crombez, Geert

    2010-05-01

    It is often assumed that attention is automatically allocated to stimuli relevant to one's actual goals. However, the existing evidence for this idea is limited in several ways. We investigated whether words relevant to a person's current goal influence the orienting of attention even when an intention to attend to the goal-relevant stimuli is not present. In two experiments, participants performed a modified spatial cueing paradigm combined with a second task that induced a goal. The results of the experiments showed that the induced goal led to the orientation of attention to goal-relevant words in the spatial cueing task. This effect was not found for words semantically related to the goal-relevant words. The results provide evidence for motivational accounts of attention, which state that the automatic allocation of attention is guided by the current goals of a person.

  19. Interactions of auditory and visual stimuli in space and time.

    PubMed

    Recanzone, Gregg H

    2009-12-01

    The nervous system has evolved to transduce different types of environmental energy independently, for example light energy is transduced by the retina whereas sound energy is transduced by the cochlea. However, the neural processing of this energy is necessarily combined, resulting in a unified percept of a real-world object or event. These percepts can be modified in the laboratory, resulting in illusions that can be used to probe how multisensory integration occurs. This paper reviews studies that have utilized such illusory percepts in order to better understand the integration of auditory and visual signals in primates. Results from human psychophysical experiments where visual stimuli alter the perception of acoustic space (the ventriloquism effect) are discussed, as are experiments probing the underlying cortical mechanisms of this integration. Similar psychophysical experiments where auditory stimuli alter the perception of visual temporal processing are also described. PMID:19393306

  20. Dopamine encoding of Pavlovian incentive stimuli diminishes with extended training.

    PubMed

    Clark, Jeremy J; Collins, Anne L; Sanford, Christina Akers; Phillips, Paul E M

    2013-02-20

    Dopamine is highly implicated both as a teaching signal in reinforcement learning and in motivating actions to obtain rewards. However, theoretical disconnects remain between the temporal encoding properties of dopamine neurons and the behavioral consequences of its release. Here, we demonstrate in rats that dopamine evoked by Pavlovian cues increases during acquisition, but dissociates from stable conditioned appetitive behavior as this signal returns to preconditioning levels with extended training. Experimental manipulation of the statistical parameters of the behavioral paradigm revealed that this attenuation of cue-evoked dopamine release during the postasymptotic period was attributable to acquired knowledge of the temporal structure of the task. In parallel, conditioned behavior became less dopamine dependent after extended training. Thus, the current work demonstrates that as the presentation of reward-predictive stimuli becomes anticipated through the acquisition of task information, there is a shift in the neurobiological substrates that mediate the motivational properties of these incentive stimuli. PMID:23426680

  1. Functional stimuli responsive hydrogel devices by self-folding

    NASA Astrophysics Data System (ADS)

    Yoon, ChangKyu; Xiao, Rui; Park, JaeHyun; Cha, Jaepyeong; Nguyen, Thao D.; Gracias, David H.

    2014-09-01

    We describe a photolithographic approach to create functional stimuli responsive, self-folding, microscale hydrogel devices using thin, gradient cross-linked hinges and thick, fully cross-linked panels. The hydrogels are composed of poly (N-isopropylacrylamide-co-acrylic acid) (pNIPAM-AAc) with reversible stimuli responsive properties just below physiological temperatures. We show that a variety of three-dimensional structures can be formed and reversibly actuated by temperature or pH. We experimentally characterized the swelling and mechanical properties of pNIPAM-AAc and developed a finite element model to rationalize self-folding and its variation with hinge thickness and swelling ratio. Finally, we highlight applications of this approach in the creation of functional devices such as self-folding polymeric micro-capsules, untethered micro-grippers and thermally steered micro-mirror systems.

  2. Stimuli-responsive Pickering emulsions: recent advances and potential applications.

    PubMed

    Tang, Juntao; Quinlan, Patrick James; Tam, Kam Chiu

    2015-05-14

    Pickering emulsions possess many advantages over traditional surfactant stabilized emulsions. For example, Pickering emulsions impart better stability against coalescence and, in many cases, are biologically compatible and environmentally friendly. These characteristics open the door for their use in a variety of industries spanning petroleum, food, biomedicine, pharmaceuticals, and cosmetics. Depending on the application, rapid, but controlled stabilization and destabilization of an emulsion may be necessary. As a result, Pickering emulsions with stimuli-responsive properties have, in recent years, received a considerable amounts of attention. This paper provides a concise and comprehensive review of Pickering emulsion systems that possess the ability to respond to an array of external triggers, including pH, temperature, CO2 concentration, light intensity, ionic strength, and magnetic field. Potential applications for which stimuli-responsive Pickering emulsion systems would be of particular value, such as emulsion polymerization, enhanced oil recovery, catalyst recovery, and cosmetics, are discussed.

  3. Chords and harmonies in mixed optical and acoustical stimuli

    NASA Astrophysics Data System (ADS)

    Hahlweg, Cornelius; Dannenberg, Florian; Dörfler, Joachim; Weber, Bernhard; Weyer, Cornelia; Gercke-Hahn, Harald; Freimuth, Steffen; Heucke, Sören; Gutzmann, Holger Ludwig

    2014-09-01

    The paper is a follow up of the work presented in last year's Optics and Music session on the perception of coherence between low frequency power modulated light and periodical acoustic stimuli. The composition of chords and harmonies from power modulated light sources and their effect as stand-alone stimulus and in conjunction with the equivalent acoustic signal is discussed. Of special interest here is the modulation near perceptible flicker frequency. The substitution of acoustical chord components by their optical counterpart and vice versa is investigated. Further, concepts of a training application for trombone players and other instrumentalists are presented: since the mean slide of the trombone does not have fixed positions, the note must be found and two players might influence each other. The possibility of helping them to synchronize by optical stimuli derived from their playing is investigated. Beside possible applications in emotional reinforcing multimedia oriented entertainment and training support for musicians, again implications for occupational medicine are discussed.

  4. Effects of buprenorphine on responses to social stimuli in healthy adults.

    PubMed

    Bershad, Anya K; Seiden, Jacob A; de Wit, Harriet

    2016-01-01

    In addition to its classical role in mediating responses to pain, the opioid system is strongly implicated in the regulation of social behavior. In young laboratory animals, low doses of opioid analgesic drugs reduce responses to isolation distress and increase play behavior. However, little is known about how opioid drugs affect responses to social stimuli in humans. Here we examined the effects of buprenorphine, a mu-opioid partial agonist and kappa-antagonist, on three dimensions of social processing: (i) responses to simulated social rejection, (ii) attention to emotional facial expressions, and (iii) emotional responses to images with and without social content. Healthy adults (N=36) attended two sessions during which they received either placebo or 0.2mg sublingual buprenorphine in randomized order, under double-blind conditions. Ninety minutes after drug administration, they completed three behavioral tasks: (i) a virtual ball-toss game in which they were first included and then excluded by the other players; (ii) an attention task in which they were shown pairs of faces (one emotional and one neutral), while the direction of their gazes was recorded using electrooculography, and (iii) a picture-viewing task, in which they rated standardized images with and without social content. During the ball-toss game, buprenorphine decreased perceived social rejection. During the attention task, the drug reduced initial attention to fearful facial expressions, without influencing attention to angry, happy, or sad faces. Finally, during the picture-viewing task, buprenorphine increased ratings of positivity of images with social content without affecting ratings of nonsocial images. These results suggest that even at low doses, opioid analgesic drugs reduce responses to some types of negative social stimuli while enhancing positive responses to social stimuli. This provides further support for the role of the opioid system in mediating responses to social rejection and

  5. Effects of buprenorphine on responses to social stimuli in healthy adults.

    PubMed

    Bershad, Anya K; Seiden, Jacob A; de Wit, Harriet

    2016-01-01

    In addition to its classical role in mediating responses to pain, the opioid system is strongly implicated in the regulation of social behavior. In young laboratory animals, low doses of opioid analgesic drugs reduce responses to isolation distress and increase play behavior. However, little is known about how opioid drugs affect responses to social stimuli in humans. Here we examined the effects of buprenorphine, a mu-opioid partial agonist and kappa-antagonist, on three dimensions of social processing: (i) responses to simulated social rejection, (ii) attention to emotional facial expressions, and (iii) emotional responses to images with and without social content. Healthy adults (N=36) attended two sessions during which they received either placebo or 0.2mg sublingual buprenorphine in randomized order, under double-blind conditions. Ninety minutes after drug administration, they completed three behavioral tasks: (i) a virtual ball-toss game in which they were first included and then excluded by the other players; (ii) an attention task in which they were shown pairs of faces (one emotional and one neutral), while the direction of their gazes was recorded using electrooculography, and (iii) a picture-viewing task, in which they rated standardized images with and without social content. During the ball-toss game, buprenorphine decreased perceived social rejection. During the attention task, the drug reduced initial attention to fearful facial expressions, without influencing attention to angry, happy, or sad faces. Finally, during the picture-viewing task, buprenorphine increased ratings of positivity of images with social content without affecting ratings of nonsocial images. These results suggest that even at low doses, opioid analgesic drugs reduce responses to some types of negative social stimuli while enhancing positive responses to social stimuli. This provides further support for the role of the opioid system in mediating responses to social rejection and

  6. Feedback and Feedforward Control of Frequency Tuning to Naturalistic Stimuli

    PubMed Central

    Chacron, Maurice J.; Maler, Leonard; Bastian, Joseph

    2016-01-01

    Sensory neurons must respond to a wide variety of natural stimuli that can have very different spatiotemporal characteristics. Optimal responsiveness to subsets of these stimuli can be achieved by devoting specialized neural circuitry to different stimulus categories, or, alternatively, this circuitry can be modulated or tuned to optimize responsiveness to current stimulus conditions. This study explores the mechanisms that enable neurons within the initial processing station of the electrosensory system of weakly electric fish to shift their tuning properties based on the spatial extent of the stimulus. These neurons are tuned to low frequencies when the stimulus is restricted to a small region within the receptive field center but are tuned to higher frequencies when the stimulus impinges on large regions of the sensory epithelium. Through a combination of modeling and in vivo electrophysiology, we reveal the respective contributions of the filtering characteristics of extended dendritic structures and feedback circuitry to this shift in tuning. Our results show that low-frequency tuning can result from the cable properties of an extended dendrite that conveys receptor-afferent information to the cell body. The shift from low- to high-frequency tuning, seen in response to spatially extensive stimuli, results from increased wide-band input attributable to activation of larger populations of receptor afferents, as well as the activation of parallel fiber feedback from the cerebellum. This feedback provides a cancellation signal with low-pass characteristics that selectively attenuates low-frequency responsiveness. Thus, with spatially extensive stimuli, these cells preferentially respond to the higher-frequency components of the receptor-afferent input. PMID:15944380

  7. Brain response to visual sexual stimuli in homosexual pedophiles

    PubMed Central

    Schiffer, Boris; Krueger, Tillmann; Paul, Thomas; de Greiff, Armin; Forsting, Michael; Leygraf, Norbert; Schedlowski, Manfred; Gizewski, Elke

    2008-01-01

    Objective The neurobiological mechanisms of deviant sexual preferences such as pedophilia are largely unknown. The objective of this study was to analyze whether brain activation patterns of homosexual pedophiles differed from those of a nonpedophile homosexual control group during visual sexual stimulation. Method A consecutive sample of 11 pedophile forensic inpatients exclusively attracted to boys and 12 age-matched homosexual control participants from a comparable socioeconomic stratum underwent functional magnetic resonance imaging during a visual sexual stimulation procedure that used sexually stimulating and emotionally neutral photographs. Sexual arousal was assessed according to a subjective rating scale. Results In contrast to sexually neutral pictures, in both groups sexually arousing pictures having both homosexual and pedophile content activated brain areas known to be involved in processing visual stimuli containing emotional content, including the occipitotemporal and prefrontal cortices. However, during presentation of the respective sexual stimuli, the thalamus, globus pallidus and striatum, which correspond to the key areas of the brain involved in sexual arousal and behaviour, showed significant activation in pedophiles, but not in control subjects. Conclusions Central processing of visual sexual stimuli in homosexual pedophiles seems to be comparable to that in nonpedophile control subjects. However, compared with homosexual control subjects, activation patterns in pedophiles refer more strongly to subcortical regions, which have previously been discussed in the context of processing reward signals and also play an important role in addictive and stimulus-controlled behaviour. Thus future studies should further elucidate the specificity of these brain regions for the processing of sexual stimuli in pedophilia and should address the generally weaker activation pattern in homosexual men. PMID:18197269

  8. Equivalence-Equivalence: Matching Stimuli with Same Discriminative Functions

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot

    2004-01-01

    Previous studies have shown that after being trained on A-B and A-C match-to-sample tasks, adults match not only same-class B and C stimuli (equivalence) but also BC compounds with same-class elements and with different-class elements (BC-BC). The assumption was that the BC-BC performances are based on matching equivalence and nonequivalence…

  9. Interpersonal touch suppresses visual processing of aversive stimuli

    PubMed Central

    Kawamichi, Hiroaki; Kitada, Ryo; Yoshihara, Kazufumi; Takahashi, Haruka K.; Sadato, Norihiro

    2015-01-01

    Social contact is essential for survival in human society. A previous study demonstrated that interpersonal contact alleviates pain-related distress by suppressing the activity of its underlying neural network. One explanation for this is that attention is shifted from the cause of distress to interpersonal contact. To test this hypothesis, we conducted a functional MRI (fMRI) study wherein eight pairs of close female friends rated the aversiveness of aversive and non-aversive visual stimuli under two conditions: joining hands either with a rubber model (rubber-hand condition) or with a close friend (human-hand condition). Subsequently, participants rated the overall comfortableness of each condition. The rating result after fMRI indicated that participants experienced greater comfortableness during the human-hand compared to the rubber-hand condition, whereas aversiveness ratings during fMRI were comparable across conditions. The fMRI results showed that the two conditions commonly produced aversive-related activation in both sides of the visual cortex (including V1, V2, and V5). An interaction between aversiveness and hand type showed rubber-hand-specific activation for (aversive > non-aversive) in other visual areas (including V1, V2, V3, and V4v). The effect of interpersonal contact on the processing of aversive stimuli was negatively correlated with the increment of attentional focus to aversiveness measured by a pain-catastrophizing scale. These results suggest that interpersonal touch suppresses the processing of aversive visual stimuli in the occipital cortex. This effect covaried with aversiveness-insensitivity, such that aversive-insensitive individuals might require a lesser degree of attentional capture to aversive-stimulus processing. As joining hands did not influence the subjective ratings of aversiveness, interpersonal touch may operate by redirecting excessive attention away from aversive characteristics of the stimuli. PMID:25904856

  10. Electrophysiological responses to bitter stimuli in primate cortex.

    PubMed

    Scott, T R; Giza, B K; Yan, J

    1998-11-30

    Studies investigating fine details of gustatory coding in the domain of each basic taste quality have been completed for sweet, salt, and sour stimuli. In the present experiment, we used chemicals that humans describe as predominantly bitter. We recorded the activity of 50 taste neurons in insular cortex of two cynomolgus macaques. Stimuli were water, fruit juice, glucose, NaCl, HCl, and 16 bitter solutions. In a multidimensional taste space the 16 bitter stimuli formed a coherent cluster composed of three main subgroups: (1) QHCl, phenylalanine, theophylline, caffeine, propyl-thiouracil (PROP), and phenylthiocarbamide (PTC), all of which humans describe as rather purely bitter, (2) MgCl2, CaCl2, NH4Cl, and arginine, which humans describe as salty-bitter, and (3) urea, cysteine, and vitamin B1, which are described as sour-bitter. Vitamin B2, histidine and nicotine were in the center of the bitter cluster. Human descriptions of taste qualities conformed well to the presumed quality of each stimulus as inferred from its position in the multidimensional space (MDS), reinforcing the use of the macaque as a neural model for human gustation.

  11. Facilitated processing of visual stimuli associated with the body.

    PubMed

    Whiteley, Louise; Kennett, Steffan; Taylor-Clarke, Marisa; Haggard, Patrick

    2004-01-01

    Recent work on tactile perception has revealed enhanced tactile acuity and speeded spatial-choice reaction times (RTs) when viewing the stimulated body site as opposed to viewing a neutral object. Here we examine whether this body-view enhancement effect extends to visual targets. Participants performed a speeded spatial discrimination between two lights attached either to their own left index finger or to a wooden finger-shaped object, making a simple distal--proximal decision. We filmed either the finger-mounted or the object-mounted lights in separate experimental blocks and the live scene was projected onto a screen in front of the participants. Thus, participants responded to identical visual targets varying only in their context: on the body or not. Results revealed a large performance advantage for the finger-mounted stimuli: reaction times were substantially reduced, while discrimination accuracy was unaffected. With this finding we address concerns associated with previous work on the processing of stimuli attributed to the self and extend the finding of a performance advantage for such stimuli to vision. PMID:15176615

  12. Non-nutritive sweeteners are not super-normal stimuli

    PubMed Central

    Antenucci, Rachel G.; Hayes, John E.

    2014-01-01

    Background It is often claimed that non-nutritive sweeteners (NNS) are ‘sweeter than sugar’, with the implicit implication high potency sweeteners are super-normal stimuli that encourage exaggerated responses. This study aimed to investigate the perceived sweetness intensity of a variety of nutritive (Sucrose, Maple Syrup, and Agave Nectar) and NNS (Acesulfame-K (AceK), Rebaudioside A (RebA), Aspartame, and Sucralose) in a large cohort of untrained participants using contemporary psychophysical methods. Methods Participants (n=401 total) rated the intensity of sweet, bitter, and metallic sensations for nutritive and NNS in water using the general labeled magnitude scale (gLMS). Results Sigmoidal Dose-Response functions were observed for all stimuli except AceK. That is, sucrose follows a sigmoidal function if the data are not artifactually linearized via prior training. More critically, there is no evidence that NNS have a maximal sweetness (intensity) greater than sucrose; indeed, the maximal sweetness for AceK, RebA and Sucralose were significantly lower than for concentrated sucrose. For these sweeteners, mixture suppression due to endogenous dose-dependent bitter or metallic sensations appears to limit maximal perceived sweetness. Conclusions In terms of perceived sweetness, non-nutritive sweeteners cannot be considered super-normal stimuli. These data do not support the view that non-nutritive sweeteners hijack or over-stimulate sweet receptors to product elevated sweet sensations. PMID:24942868

  13. Resistance to extinction following habituation to behaviourally disruptive novel stimuli.

    PubMed

    Haggbloom, S J; Brewer, V R

    1989-11-01

    Three experiments tested the prediction, derived from generalized frustration theory (Amsel, 1972), that habituation to behaviourally disruptive stimuli increases resistance to extinction in the runway. In each experiment, rats received initial consistent reinforcement (CRF) training and then either continued CRF (Groups C), partial reinforcement (PRF) training (Groups P), or CRF accompanied by presentations of a novel tactile, tone, or obstacle stimulus (Groups D) in Experiments 1-3, respectively. PRF increased resistance to extinction whether non-reinforcement disrupted behaviour (Experiment 1) or not (Experiments 2 and 3). The tactile and obstacle stimuli very substantially disrupted behaviour, and the tone produced a modest disruption of behaviour. All subjects habituated to the disruptive effects of these stimuli, but Group D was not more resistant to extinction than Group C in any experiment. The results suggest that non-reinforcement has unique stimulus properties, a consequence of which is that habituation to other sources of disruptive stimulation does not promote responding to non-reinforcement in extinction.

  14. Endogenous sequential cortical activity evoked by visual stimuli.

    PubMed

    Carrillo-Reid, Luis; Miller, Jae-Eun Kang; Hamm, Jordan P; Jackson, Jesse; Yuste, Rafael

    2015-06-10

    Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

  15. Endogenous Sequential Cortical Activity Evoked by Visual Stimuli

    PubMed Central

    Miller, Jae-eun Kang; Hamm, Jordan P.; Jackson, Jesse; Yuste, Rafael

    2015-01-01

    Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

  16. A dual-stimuli-responsive fluorescent switch ultrathin film.

    PubMed

    Li, Zhixiong; Liang, Ruizheng; Liu, Wendi; Yan, Dongpeng; Wei, Min

    2015-10-28

    Stimuli-responsive fluorescent switches have shown broad applications in optical devices, biological materials and intelligent responses. Herein, we describe the design and fabrication of a dual-stimuli-responsive fluorescent switch ultrathin film (UTF) via a three-step layer-by-layer (LBL) technique: (i) encapsulation of spiropyran (SP) within an amphiphilic block copolymer (PTBEM) to give the (SP@PTBEM) micelle; (ii) the mixture of riboflavin (Rf) and poly(styrene 4-sulfonate) (PSS) to enhance the adhesion ability of small molecules; (iii) assembly of negatively charged SP@PTBEM and Rf-PSS with cationic layered double hydroxide (LDH) nanoplatelets to obtain the (Rf-PSS/LDH/SP@PTBEM)n UTFs (n: bilayer number). The assembly process of the UTFs and their luminescence properties, as monitored by fluorescence spectroscopy and scanning electron microscopy (SEM), present a uniform and ordered layered structure with stepwise growth. The resulting Rf-PSS/LDH/SP@PTBEM UTF serves as a three-state switchable multicolor (green, yellow, and red) luminescent system based on stimulation from UV/Vis light and pH, with an acceptable reversibility. Therefore, this work provides a facile way to fabricate stimuli-responsive solid-state film switches with tunable-color luminescence, which have potential applications in the areas of displays, sensors, and rewritable optical memory and fluorescent logic devices. PMID:26400734

  17. Extended cortical activations during evaluating successive pain stimuli.

    PubMed

    Lötsch, Jörn; Walter, Carmen; Felden, Lisa; Preibisch, Christine; Nöth, Ulrike; Martin, Till; Anti, Sandra; Deichmann, Ralf; Oertel, Bruno G

    2012-08-01

    Comparing pain is done in daily life and involves short-term memorizing and attention focusing. This event-related functional magnetic resonance imaging study investigated the short-term brain activations associated with the comparison of pain stimuli using a delayed discrimination paradigm. Fourteen healthy young volunteers compared two successive pain stimuli administered at a 10 s interval to the same location at the nasal mucosa. Fourteen age- and sex-matched subjects received similar pain stimuli without performing the comparison task. With the comparison task, the activations associated with the second pain stimulus were significantly greater than with the first stimulus in the anterior insular cortex and the primary somatosensory area. This was observed on the background of a generally increased stimulus-associated brain activation in the presence of the comparison task that included regions of the pain matrix (insular cortex, primary and secondary somatosensory area, midcingulate cortex, supplemental motor area) and regions associated with attention, decision making, working memory and body recognition (frontal and temporal gyri, inferior parietal lobule, precuneus, lingual cortices). This data provides a cerebral correlate for the role of pain as a biological alerting system that gains the subject's attention and then dominates most other perceptions and activities involving pain-specific and non-pain-specific brain regions.

  18. Fertility of beef cattle females with mating stimuli around insemination.

    PubMed

    Rodriguez, R O; Rivera, M J

    1999-01-29

    An experiment was conducted to test the hypothesis that sterile mounts around insemination improves pregnancy rate to artificial insemination (AI) and to define the effects of age, season, time to complete AI and time of day of insemination. A total of 178 Simbrah females were randomly assigned by calving date and body condition to one of three treatments during two consecutive years: (1) mating stimuli with a sterile bull at the time the cows were detected in estrus; (2) mating stimuli immediately after completing AI; (3) without mating stimuli. All cows and heifers were maintained under the same conditions of handling and feeding within the two breeding seasons (winter 1995 and summer 1996). Vasectomized bulls were used for the sterile mounts. Cows and heifers that were given a sterile mount at the time of detection of estrus, had an increased pregnancy rate (60.0%) compared with females given a sterile mount after completing AI (25.4%) or females without the sterile mount (35.6%) (P < 0.01). Age, season, time to complete AI and time of day of AI were all non-significant (P > 0.05). Therefore, there is a biostimulatory effect of mating at the time beef cattle females are detected in estrus, on pregnancy rates to AI.

  19. Neural Conflict–Control Mechanisms Improve Memory for Target Stimuli

    PubMed Central

    Krebs, Ruth M.; Boehler, Carsten N.; De Belder, Maya; Egner, Tobias

    2015-01-01

    According to conflict-monitoring models, conflict serves as an internal signal for reinforcing top-down attention to task-relevant information. While evidence based on measures of ongoing task performance supports this idea, implications for long-term consequences, that is, memory, have not been tested yet. Here, we evaluated the prediction that conflict-triggered attentional enhancement of target-stimulus processing should be associated with superior subsequent memory for those stimuli. By combining functional magnetic resonance imaging (fMRI) with a novel variant of a face-word Stroop task that employed trial-unique face stimuli as targets, we were able to assess subsequent (incidental) memory for target faces as a function of whether a given face had previously been accompanied by congruent, neutral, or incongruent (conflicting) distracters. In line with our predictions, incongruent distracters not only induced behavioral conflict, but also gave rise to enhanced memory for target faces. Moreover, conflict-triggered neural activity in prefrontal and parietal regions was predictive of subsequent retrieval success, and displayed conflict-enhanced functional coupling with medial-temporal lobe regions. These data provide support for the proposal that conflict evokes enhanced top-down attention to task-relevant stimuli, thereby promoting their encoding into long-term memory. Our findings thus delineate the neural mechanisms of a novel link between cognitive control and memory. PMID:24108799

  20. Attention modulates the dorsal striatum response to love stimuli.

    PubMed

    Langeslag, Sandra J E; van der Veen, Frederik M; Röder, Christian H

    2014-02-01

    In previous functional magnetic resonance imaging (fMRI) studies concerning romantic love, several brain regions including the caudate and putamen have consistently been found to be more responsive to beloved-related than control stimuli. In those studies, infatuated individuals were typically instructed to passively view the stimuli or to think of the viewed person. In the current study, we examined how the instruction to attend to, or ignore the beloved modulates the response of these brain areas. Infatuated individuals performed an oddball task in which pictures of their beloved and friend served as targets and distractors. The dorsal striatum showed greater activation for the beloved than friend, but only when they were targets. The dorsal striatum actually tended to show less activation for the beloved than the friend when they were distractors. The longer the love and relationship duration, the smaller the response of the dorsal striatum to beloved-distractor stimuli was. We interpret our findings in terms of reinforcement learning. By virtue of using a cognitive task with a full factorial design, we show that the dorsal striatum is not activated by beloved-related information per se, but only by beloved-related information that is attended.

  1. Goldfish and oscars have comparable responsiveness to dipole stimuli

    NASA Astrophysics Data System (ADS)

    Nauroth, Ines Eva; Mogdans, Joachim

    2009-12-01

    The relative roles of the fish lateral line and inner ear for the perception of hydrodynamic stimuli are poorly investigated. Here, we studied responsiveness to a 100 Hz vibrating sphere (dipole stimulus) of goldfish and oscars, two species that differ in peripheral lateral line morphology, inner ear morphology, mechanical linkage between inner ear and swim bladder, and inner ear sensitivity. We measured unconditioned dipole-evoked changes in breathing activity in still water and in the presence of a 5-cm s-1 background flow. In still water, individuals from both species responded to sound pressure levels (SPLs) between 92 and 109 dB SPL re 1 μPaRMS. Responsiveness was not affected by background flow or by temporary inactivation of the lateral line. The data suggest that fish with different lateral line and inner ear morphologies have similar sensitivities to vibrating sphere stimuli and can detect and respond to dipole sources equally well in still water and in moderate background flows. Moreover, behavioral responses were not dependent on a functional lateral line, suggesting that in this type of experiment, the inner ear is the dominant sense organ for the perception of hydrodynamic stimuli.

  2. Hemispheric specialization in dogs for processing different acoustic stimuli.

    PubMed

    Siniscalchi, Marcello; Quaranta, Angelo; Rogers, Lesley J

    2008-01-01

    Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions. PMID:18843371

  3. Expectations accelerate entry of visual stimuli into awareness.

    PubMed

    Pinto, Yair; van Gaal, Simon; de Lange, Floris P; Lamme, Victor A F; Seth, Anil K

    2015-01-01

    How do expectations influence transitions between unconscious and conscious perceptual processing? According to the influential predictive processing framework, perceptual content is determined by predictive models of the causes of sensory signals. On one interpretation, conscious contents arise when predictive models are verified by matching sensory input (minimizing prediction error). On another, conscious contents arise when surprising events falsify current perceptual predictions. Finally, the cognitive impenetrability account posits that conscious perception is not affected by such higher level factors. To discriminate these positions, we combined predictive cueing with continuous flash suppression (CFS) in which the relative contrast of a target image gradually increases over time. In four experiments we established that expected stimuli enter consciousness faster than neutral or unexpected stimuli. These effects are difficult to account for in terms of response priming, pre-existing stimulus associations, or the attentional mechanisms that cause asynchronous temporal order judgments (of simultaneously presented stimuli). Our results further suggest that top-down expectations play a larger role when bottom-up input is ambiguous, in line with predictive processing accounts of perception. Taken together, our findings support the hypothesis that conscious access depends on verification of perceptual predictions. PMID:26114676

  4. Fertility of beef cattle females with mating stimuli around insemination.

    PubMed

    Rodriguez, R O; Rivera, M J

    1999-01-29

    An experiment was conducted to test the hypothesis that sterile mounts around insemination improves pregnancy rate to artificial insemination (AI) and to define the effects of age, season, time to complete AI and time of day of insemination. A total of 178 Simbrah females were randomly assigned by calving date and body condition to one of three treatments during two consecutive years: (1) mating stimuli with a sterile bull at the time the cows were detected in estrus; (2) mating stimuli immediately after completing AI; (3) without mating stimuli. All cows and heifers were maintained under the same conditions of handling and feeding within the two breeding seasons (winter 1995 and summer 1996). Vasectomized bulls were used for the sterile mounts. Cows and heifers that were given a sterile mount at the time of detection of estrus, had an increased pregnancy rate (60.0%) compared with females given a sterile mount after completing AI (25.4%) or females without the sterile mount (35.6%) (P < 0.01). Age, season, time to complete AI and time of day of AI were all non-significant (P > 0.05). Therefore, there is a biostimulatory effect of mating at the time beef cattle females are detected in estrus, on pregnancy rates to AI. PMID:10090564

  5. Hemispheric specialization in dogs for processing different acoustic stimuli.

    PubMed

    Siniscalchi, Marcello; Quaranta, Angelo; Rogers, Lesley J

    2008-01-01

    Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions.

  6. Taste coding of complex naturalistic taste stimuli and traditional taste stimuli in the parabrachial pons of the awake, freely licking rat.

    PubMed

    Sammons, Joshua D; Weiss, Michael S; Victor, Jonathan D; Di Lorenzo, Patricia M

    2016-07-01

    Several studies have shown that taste-responsive cells in the brainstem taste nuclei of rodents respond to sensory qualities other than gustation. Such data suggest that cells in the classical gustatory brainstem may be better tuned to respond to stimuli that engage multiple sensory modalities than to stimuli that are purely gustatory. Here, we test this idea by recording the electrophysiological responses to complex, naturalistic stimuli in single neurons in the parabrachial pons (PbN, the second neural relay in the central gustatory pathway) in awake, freely licking rats. Following electrode implantation and recovery, we presented both prototypical and naturalistic taste stimuli and recorded the responses in the PbN. Prototypical taste stimuli (NaCl, sucrose, citric acid, and caffeine) and naturalistic stimuli (clam juice, grape juice, lemon juice, and coffee) were matched for taste quality and intensity (concentration). Umami (monosodium glutamate + inosine monophosphate) and fat (diluted heavy cream) were also tested. PbN neurons responded to naturalistic stimuli as much or more than to prototypical taste stimuli. Furthermore, they convey more information about naturalistic stimuli than about prototypical ones. Moreover, multidimensional scaling analyses showed that across unit responses to naturalistic stimuli were more widely separated than responses to prototypical taste stimuli. Interestingly, cream evoked a robust and widespread response in PbN cells. Collectively, these data suggest that natural foods are more potent stimulators of PbN cells than purely gustatory stimuli. Probing PbN cells with pure taste stimuli may underestimate the response repertoire of these cells.

  7. Taste coding of complex naturalistic taste stimuli and traditional taste stimuli in the parabrachial pons of the awake, freely licking rat.

    PubMed

    Sammons, Joshua D; Weiss, Michael S; Victor, Jonathan D; Di Lorenzo, Patricia M

    2016-07-01

    Several studies have shown that taste-responsive cells in the brainstem taste nuclei of rodents respond to sensory qualities other than gustation. Such data suggest that cells in the classical gustatory brainstem may be better tuned to respond to stimuli that engage multiple sensory modalities than to stimuli that are purely gustatory. Here, we test this idea by recording the electrophysiological responses to complex, naturalistic stimuli in single neurons in the parabrachial pons (PbN, the second neural relay in the central gustatory pathway) in awake, freely licking rats. Following electrode implantation and recovery, we presented both prototypical and naturalistic taste stimuli and recorded the responses in the PbN. Prototypical taste stimuli (NaCl, sucrose, citric acid, and caffeine) and naturalistic stimuli (clam juice, grape juice, lemon juice, and coffee) were matched for taste quality and intensity (concentration). Umami (monosodium glutamate + inosine monophosphate) and fat (diluted heavy cream) were also tested. PbN neurons responded to naturalistic stimuli as much or more than to prototypical taste stimuli. Furthermore, they convey more information about naturalistic stimuli than about prototypical ones. Moreover, multidimensional scaling analyses showed that across unit responses to naturalistic stimuli were more widely separated than responses to prototypical taste stimuli. Interestingly, cream evoked a robust and widespread response in PbN cells. Collectively, these data suggest that natural foods are more potent stimulators of PbN cells than purely gustatory stimuli. Probing PbN cells with pure taste stimuli may underestimate the response repertoire of these cells. PMID:27121585

  8. Development of degradable renewable polymers and stimuli-responsive nanocomposites

    NASA Astrophysics Data System (ADS)

    Eyiler, Ersan

    The overall goal of this research was to explore new living radical polymerization methods and the blending of renewable polymers. Towards this latter goal, polylactic acid (PLA) was blended with a new renewable polymer, poly(trimethylene-malonate) (PTM), with the aim of improving mechanical properties, imparting faster degradation, and examining the relationship between degradation and mechanical properties. Blend films of PLA and PTM with various ratios (5, 10, and 20 wt %) were cast from chloroform. Partially miscible blends exhibited Young's modulus and elongation-to-break values that significantly extend PLA's usefulness. Atomic force microscopy (AFM) data showed that incorporation of 10 wt% PTM into PLA matrix exhibited a Young's modulus of 4.61 GPa, which is significantly higher than that of neat PLA (1.69 GPa). The second part of the bioplastics study involved a one-week hydrolytic degradation study of PTM and another new bioplastic, poly(trimethylene itaconate) (PTI) using DI water (pH 5.4) at room temperature, and the effects of degradation on crystallinity and mechanical properties of these films were examined by differential scanning calorimetry (DSC) and AFM. PTI showed an increase in crystallinity with degradation, which was attributed to predominately degradation of free amorphous regions. Depending on the crystallinity, the elastic modulus increased at first, and decreased slightly. Both bulk and surface-tethered stimuli-responsive polymers were studied on amine functionalized magnetite (Fe3O4) nanoparticles. Stimuli-responsive polymers studied, including poly(N-isopropylacrylamide) (PNIPAM), poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), and poly(itaconic acid) (PIA), were grafted via surface-initiated aqueous atom transfer radical polymerization (SI-ATRP). Both Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) spectroscopies showed the progression of the grafting. The change in particle size as a

  9. Discrimination of two neighboring intra- and intermodal empty time intervals marked by three successive stimuli.

    PubMed

    Kuroda, Tsuyoshi; Hasuo, Emi; Labonté, Katherine; Laflamme, Vincent; Grondin, Simon

    2014-06-01

    We investigated the discrimination of two neighboring intra- or inter-modal empty time intervals marked by three successive stimuli. Each of the three markers was a flash (visual-V) or a sound (auditory-A). The first and last markers were of the same modality, while the second one was either A or V, resulting in four conditions: VVV, VAV, AVA and AAA. Participants judged whether the second interval, whose duration was systematically varied, was shorter or longer than the 500-ms first interval. Compared with VVV and AAA, discrimination was impaired with VAV, but not so much with AVA (in Experiment 1). Whereas VAV and AVA consisted of the same set of single intermodal intervals (VA and AV), discrimination was impaired in the VAV compared to the AVA condition. This difference between VAV and AVA could not be attributed to the participants' strategy to perform the discrimination task, e.g., ignoring the standard interval or replacing the visual stimuli with sounds in their mind (in Experiment 2). These results are discussed in terms of sequential grouping according to sensory similarity.

  10. Basic Emotions in the Nencki Affective Word List (NAWL BE): New Method of Classifying Emotional Stimuli

    PubMed Central

    Wierzba, Małgorzata; Riegel, Monika; Wypych, Marek; Jednoróg, Katarzyna; Turnau, Paweł; Grabowska, Anna; Marchewka, Artur

    2015-01-01

    The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of Polish words suitable for studying various aspects of language and emotions. Though the NAWL was originally based on the most commonly used dimensional approach, it is not the only way of studying emotions. Another framework is based on discrete emotional categories. Since the two perspectives are recognized as complementary, the aim of the present study was to supplement the NAWL database by the addition of categories corresponding to basic emotions. Thus, 2902 Polish words from the NAWL were presented to 265 subjects, who were instructed to rate them according to the intensity of each of the five basic emotions: happiness, anger, sadness, fear and disgust. The general characteristics of the present word database, as well as the relationships between the studied variables are shown to be consistent with typical patterns found in previous studies using similar databases for different languages. Here we present the Basic Emotions in the Nencki Affective Word List (NAWL BE) as a database of verbal material suitable for highly controlled experimental research. To make the NAWL more convenient to use, we introduce a comprehensive method of classifying stimuli to basic emotion categories. We discuss the advantages of our method in comparison to other methods of classification. Additionally, we provide an interactive online tool (http://exp.lobi.nencki.gov.pl/nawl-analysis) to help researchers browse and interactively generate classes of stimuli to meet their specific requirements. PMID:26148193

  11. Basic Emotions in the Nencki Affective Word List (NAWL BE): New Method of Classifying Emotional Stimuli.

    PubMed

    Wierzba, Małgorzata; Riegel, Monika; Wypych, Marek; Jednoróg, Katarzyna; Turnau, Paweł; Grabowska, Anna; Marchewka, Artur

    2015-01-01

    The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of Polish words suitable for studying various aspects of language and emotions. Though the NAWL was originally based on the most commonly used dimensional approach, it is not the only way of studying emotions. Another framework is based on discrete emotional categories. Since the two perspectives are recognized as complementary, the aim of the present study was to supplement the NAWL database by the addition of categories corresponding to basic emotions. Thus, 2902 Polish words from the NAWL were presented to 265 subjects, who were instructed to rate them according to the intensity of each of the five basic emotions: happiness, anger, sadness, fear and disgust. The general characteristics of the present word database, as well as the relationships between the studied variables are shown to be consistent with typical patterns found in previous studies using similar databases for different languages. Here we present the Basic Emotions in the Nencki Affective Word List (NAWL BE) as a database of verbal material suitable for highly controlled experimental research. To make the NAWL more convenient to use, we introduce a comprehensive method of classifying stimuli to basic emotion categories. We discuss the advantages of our method in comparison to other methods of classification. Additionally, we provide an interactive online tool (http://exp.lobi.nencki.gov.pl/nawl-analysis) to help researchers browse and interactively generate classes of stimuli to meet their specific requirements.

  12. Event-related brain potentials in selective listening to frequent and rare stimuli.

    PubMed

    Alho, K; Lavikainen, J; Reinikainen, K; Sams, M; Näätänen, R

    1990-01-01

    Our previous event-related brain potential (ERP) results suggest that during selective listening, relevant stimuli are selected for further processing by comparing each stimulus to an "attentional trace," a neuronal representation of the physical features of the relevant stimuli that distinguish them from the irrelevant stimuli. This comparison process is reflected by the early component of the processing negativity (PN), which is largest and longest to the relevant stimuli (perfectly matching with the trace). In the present study, the subjects selectively listened to designated tone stimuli which randomly appeared among irrelevant tones of a different pitch. The probability of relevant stimuli in a block was varied. The processing negativity elicited by relevant stimuli was smaller the less frequent they were. The results support the attentional-trace theory of selective attention, which proposes that, in addition to active maintenance, the trace also depends on the rate of sensory reinforcement provided by the relevant stimuli.

  13. Suppression to visual, auditory and gustatory stimuli habituates normally in rats with excitotoxic lesions of the perirhinal cortex

    PubMed Central

    Robinson, Jasper; Sanderson, David J.; Aggleton, John P.; Jenkins, Trisha A.

    2014-01-01

    In 3 habituation experiments, rats with excitotoxic lesions of the perirhinal cortex were found to be indistinguishable from control rats. Two of the habituation experiments examined the habituation of suppression of responding on an appetitive, instrumental baseline. One of those experiments used stimuli selected from the visual modality (lights), the other used auditory stimuli. The third experiment examined habituation of suppression of novel-flavored water consumption. In contrast to the null results on the habituation experiments, the perirhinal lesions disrupted transfer performance on a configural, visual discrimination, indicating the behavioral effectiveness of the lesions. Implications for comparator theories of habituation are considered and we conclude that others’ demonstrations of the sensitivity of object recognition to perirhinal cortex damage is not the result of standard habituation. PMID:20001107

  14. The PreViBOSS project: study the short term predictability of the visibility change during the Fog life cycle, from surface and satellite observation

    NASA Astrophysics Data System (ADS)

    Elias, T.; Haeffelin, M.; Ramon, D.; Gomes, L.; Brunet, F.; Vrac, M.; Yiou, P.; Hello, G.; Petithomme, H.

    2010-07-01

    Fog prejudices major activities as transport and Earth observation, by critically reducing atmospheric visibility with no continuity in time and space. Fog is also an essential factor of air quality and climate as it modifies particle properties of the surface atmospheric layer. Complexity, diversity and the fine scale of processes make uncertain by current numerical weather prediction models, not only visibility diagnosis but also fog event prediction. Extensive measurements of atmospheric parameters are made on the SIRTA since 1997 to document physical processes over the atmospheric column, in the Paris suburb area, typical of an environment intermittently under oceanic influence and affected by urban and industrial pollution. The ParisFog field campaign hosted in SIRTA during 6-month in winter 2006-2007 resulted in the deployment of instrumentation specifically dedicated to study physical processes in the fog life cycle: thermodynamical, radiative, dynamical, microphysical processes. Analysis of the measurements provided a preliminary climatology of the episodes of reduced visibility, chronology of processes was delivered by examining time series of measured parameters and a closure study was performed on optical and microphysical properties of particles (aerosols to droplets) during the life cycle of a radiative fog, providing the relative contribution of several particle groups to extinction in clear-sky conditions, in haze and in fog. PreViBOSS is a 3-year project scheduled to start this year. The aim is to improve the short term prediction of changes in atmospheric visibility, at a local scale. It proposes an innovative approach: applying the Generalised Additive Model statistical method to the detailed and extended dataset acquired at SIRTA. This method offers the opportunity to explore non linear relationships between parameters, which are not yet integrated in current numerical models. Emphasis will be put on aerosols and their impact on the fog life

  15. A dual-stimuli-responsive fluorescent switch ultrathin film

    NASA Astrophysics Data System (ADS)

    Li, Zhixiong; Liang, Ruizheng; Liu, Wendi; Yan, Dongpeng; Wei, Min

    2015-10-01

    Stimuli-responsive fluorescent switches have shown broad applications in optical devices, biological materials and intelligent responses. Herein, we describe the design and fabrication of a dual-stimuli-responsive fluorescent switch ultrathin film (UTF) via a three-step layer-by-layer (LBL) technique: (i) encapsulation of spiropyran (SP) within an amphiphilic block copolymer (PTBEM) to give the (SP@PTBEM) micelle; (ii) the mixture of riboflavin (Rf) and poly(styrene 4-sulfonate) (PSS) to enhance the adhesion ability of small molecules; (iii) assembly of negatively charged SP@PTBEM and Rf-PSS with cationic layered double hydroxide (LDH) nanoplatelets to obtain the (Rf-PSS/LDH/SP@PTBEM)n UTFs (n: bilayer number). The assembly process of the UTFs and their luminescence properties, as monitored by fluorescence spectroscopy and scanning electron microscopy (SEM), present a uniform and ordered layered structure with stepwise growth. The resulting Rf-PSS/LDH/SP@PTBEM UTF serves as a three-state switchable multicolor (green, yellow, and red) luminescent system based on stimulation from UV/Vis light and pH, with an acceptable reversibility. Therefore, this work provides a facile way to fabricate stimuli-responsive solid-state film switches with tunable-color luminescence, which have potential applications in the areas of displays, sensors, and rewritable optical memory and fluorescent logic devices.Stimuli-responsive fluorescent switches have shown broad applications in optical devices, biological materials and intelligent responses. Herein, we describe the design and fabrication of a dual-stimuli-responsive fluorescent switch ultrathin film (UTF) via a three-step layer-by-layer (LBL) technique: (i) encapsulation of spiropyran (SP) within an amphiphilic block copolymer (PTBEM) to give the (SP@PTBEM) micelle; (ii) the mixture of riboflavin (Rf) and poly(styrene 4-sulfonate) (PSS) to enhance the adhesion ability of small molecules; (iii) assembly of negatively charged SP

  16. Orienting response reinstatement and dishabituation: effects of substituting, adding, and deleting components of nonsignificant stimuli.

    PubMed

    Ben-Shakhar, G; Gati, I; Ben-Bassat, N; Sniper, G

    2000-01-01

    The prediction that orienting response (OR) reinstatement is negatively related to the measure of common features, shared by the stimulus input and representations of preceding events, and positively related to the measure of their distinctive features, was examined. A nonsignificant test stimulus (TS) was presented after nine repetitions of a standard stimulus (SS), followed by two additional repetitions of SS. TS was created by either substituting 0, 1, or 2 components of SS (Experiment 1), or by either adding or deleting 0, 1, or 2 components of SS (Experiment 2). Skin conductance changes to TS (OR reinstatement) and the subsequent SS (dishabituation) were used as dependent measures. The results of Experiment 1 supported the prediction that substituting components of neutral stimuli affects OR reinstatement, with a larger effect for between-categories than within-categories substitution. Experiment 2 demonstrated that adding and deleting components similarly affects OR reinstatement.

  17. Freezing Behavior as a Response to Sexual Visual Stimuli as Demonstrated by Posturography

    PubMed Central

    Mouras, Harold; Lelard, Thierry; Ahmaidi, Said; Godefroy, Olivier; Krystkowiak, Pierre

    2015-01-01

    Posturographic changes in motivational conditions remain largely unexplored in the context of embodied cognition. Over the last decade, sexual motivation has been used as a good canonical working model to study motivated social interactions. The objective of this study was to explore posturographic variations in response to visual sexual videos as compared to neutral videos. Our results support demonstration of a freezing-type response in response to sexually explicit stimuli compared to other conditions, as demonstrated by significantly decreased standard deviations for (i) the center of pressure displacement along the mediolateral and anteroposterior axes and (ii) center of pressure’s displacement surface. These results support the complexity of the motor correlates of sexual motivation considered to be a canonical functional context to study the motor correlates of motivated social interactions. PMID:25992571

  18. Freezing behavior as a response to sexual visual stimuli as demonstrated by posturography.

    PubMed

    Mouras, Harold; Lelard, Thierry; Ahmaidi, Said; Godefroy, Olivier; Krystkowiak, Pierre

    2015-01-01

    Posturographic changes in motivational conditions remain largely unexplored in the context of embodied cognition. Over the last decade, sexual motivation has been used as a good canonical working model to study motivated social interactions. The objective of this study was to explore posturographic variations in response to visual sexual videos as compared to neutral videos. Our results support demonstration of a freezing-type response in response to sexually explicit stimuli compared to other conditions, as demonstrated by significantly decreased standard deviations for (i) the center of pressure displacement along the mediolateral and anteroposterior axes and (ii) center of pressure's displacement surface. These results support the complexity of the motor correlates of sexual motivation considered to be a canonical functional context to study the motor correlates of motivated social interactions.

  19. Do Live versus Audio-Recorded Narrative Stimuli Influence Young Children's Narrative Comprehension and Retell Quality?

    ERIC Educational Resources Information Center

    Kim, Young-Suk Grace

    2016-01-01

    Purpose: The primary aim of the present study was to examine whether different ways of presenting narrative stimuli (i.e., live narrative stimuli versus audio-recorded narrative stimuli) influence children's performances on narrative comprehension and oral-retell quality. Method: Children in kindergarten (n = 54), second grade (n = 74), and fourth…

  20. PC-compatible computer-generated stimuli for video-task testing

    NASA Technical Reports Server (NTRS)

    Washburn, David A.

    1990-01-01

    A program for automatic computer generation of novel nonverbal stimuli is described. The program, STIMGEN, allows menu-driven control over the type and appearance of stimuli. Data are presented in which two monkeys matched to sample with high accuracy using stimuli generated with STIMGEN. These data are interpreted to support the usefulness and value of automatic stimulus generation in a variety of applications.

  1. Teaching children with autism to engage in conversational exchanges: script fading with embedded textual stimuli.

    PubMed Central

    Sarokoff, R A; Taylor, B A; Poulson, C L

    2001-01-01

    A multiple baseline across three sets of stimuli was used to assess the effects of a script-fading procedure using embedded text to teach 2 children with autism to engage in conversation statements about the stimuli. Both students stated all the scripted statements, and unscripted statements also increased. Generalization was assessed with novel peers and with untrained stimuli. PMID:11317993

  2. Evaluating Preference for Familiar and Novel Stimuli across a Large Group of Children with Autism

    ERIC Educational Resources Information Center

    Kenzer, Amy L.; Bishop, Michele R.

    2011-01-01

    This study examined relative preference for familiar and novel stimuli for 31 children with autism. Preference surveys, completed by 39 staff members, identified high and low preference familiar stimuli for each participant. Novel stimuli were selected by experimenters and included items that were not reported on a preference survey for that…

  3. Beyond the classical receptive field: The effect of contextual stimuli.

    PubMed

    Spillmann, Lothar; Dresp-Langley, Birgitta; Tseng, Chia-Huei

    2015-01-01

    Following the pioneering studies of the receptive field (RF), the RF concept gained further significance for visual perception by the discovery of input effects from beyond the classical RF. These studies demonstrated that neuronal responses could be modulated by stimuli outside their RFs, consistent with the perception of induced brightness, color, orientation, and motion. Lesion scotomata are similarly modulated perceptually from the surround by RFs that have migrated from the interior to the outer edge of the scotoma and in this way provide filling-in of the void. Large RFs are advantageous to this task. In higher visual areas, such as the middle temporal and inferotemporal lobe, RFs increase in size and lose most of their retinotopic organization while encoding increasingly complex features. Whereas lower-level RFs mediate perceptual filling-in, contour integration, and figure-ground segregation, RFs at higher levels serve the perception of grouping by common fate, biological motion, and other biologically relevant stimuli, such as faces. Studies in alert monkeys while freely viewing natural scenes showed that classical and nonclassical RFs cooperate in forming representations of the visual world. Today, our understanding of the mechanisms underlying the RF is undergoing a quantum leap. What had started out as a hierarchical feed-forward concept for simple stimuli, such as spots, lines, and bars, now refers to mechanisms involving ascending, descending, and lateral signal flow. By extension of the bottom-up paradigm, RFs are nowadays understood as adaptive processors, enabling the predictive coding of complex scenes. Top-down effects guiding attention and tuned to task-relevant information complement the bottom-up analysis. PMID:26200888

  4. Regional brain responses in nulliparous women to emotional infant stimuli.

    PubMed

    Montoya, Jessica L; Landi, Nicole; Kober, Hedy; Worhunsky, Patrick D; Rutherford, Helena J V; Mencl, W Einar; Mayes, Linda C; Potenza, Marc N

    2012-01-01

    Infant cries and facial expressions influence social interactions and elicit caretaking behaviors from adults. Recent neuroimaging studies suggest that neural responses to infant stimuli involve brain regions that process rewards. However, these studies have yet to investigate individual differences in tendencies to engage or withdraw from motivationally relevant stimuli. To investigate this, we used event-related fMRI to scan 17 nulliparous women. Participants were presented with novel infant cries of two distress levels (low and high) and unknown infant faces of varying affect (happy, sad, and neutral) in a randomized, counter-balanced order. Brain activation was subsequently correlated with scores on the Behavioral Inhibition System/Behavioral Activation System scale. Infant cries activated bilateral superior and middle temporal gyri (STG and MTG) and precentral and postcentral gyri. Activation was greater in bilateral temporal cortices for low- relative to high-distress cries. Happy relative to neutral faces activated the ventral striatum, caudate, ventromedial prefrontal, and orbitofrontal cortices. Sad versus neutral faces activated the precuneus, cuneus, and posterior cingulate cortex, and behavioral activation drive correlated with occipital cortical activations in this contrast. Behavioral inhibition correlated with activation in the right STG for high- and low-distress cries relative to pink noise. Behavioral drive correlated inversely with putamen, caudate, and thalamic activations for the comparison of high-distress cries to pink noise. Reward-responsiveness correlated with activation in the left precentral gyrus during the perception of low-distress cries relative to pink noise. Our findings indicate that infant cry stimuli elicit activations in areas implicated in auditory processing and social cognition. Happy infant faces may be encoded as rewarding, whereas sad faces activate regions associated with empathic processing. Differences in motivational

  5. Parasympathetic Stimuli on Bronchial and Cardiovascular Systems in Humans

    PubMed Central

    Zannin, Emanuela; Pellegrino, Riccardo; Di Toro, Alessandro; Antonelli, Andrea; Dellacà, Raffaele L.; Bernardi, Luciano

    2015-01-01

    Background It is not known whether parasympathetic outflow simultaneously acts on bronchial tone and cardiovascular system waxing and waning both systems in parallel, or, alternatively, whether the regulation is more dependent on local factors and therefore independent on each system. The aim of this study was to evaluate the simultaneous effect of different kinds of stimulations, all associated with parasympathetic activation, on bronchomotor tone and cardiovascular autonomic regulation. Methods Respiratory system resistance (Rrs, forced oscillation technique) and cardio-vascular activity (heart rate, oxygen saturation, tissue oxygenation index, blood pressure) were assessed in 13 volunteers at baseline and during a series of parasympathetic stimuli: O2 inhalation, stimulation of the carotid sinus baroreceptors by neck suction, slow breathing, and inhalation of methacholine. Results Pure cholinergic stimuli, like O2 inhalation and baroreceptors stimulation, caused an increase in Rrs and a reduction in heart rate and blood pressure. Slow breathing led to bradycardia and hypotension, without significant changes in Rrs. However slow breathing was associated with deep inhalations, and Rrs evaluated at the baseline lung volumes was significantly increased, suggesting that the large tidal volumes reversed the airways narrowing effect of parasympathetic activation. Finally inhaled methacholine caused marked airway narrowing, while the cardiovascular variables were unaffected, presumably because of the sympathetic activity triggered in response to hypoxemia. Conclusions All parasympathetic stimuli affected bronchial tone and moderately affected also the cardiovascular system. However the response differed depending on the nature of the stimulus. Slow breathing was associated with large tidal volumes that reversed the airways narrowing effect of parasympathetic activation. PMID:26046774

  6. Neurophysiological responses to music and vibroacoustic stimuli in Rett syndrome.

    PubMed

    Bergström-Isacsson, Märith; Lagerkvist, Bengt; Holck, Ulla; Gold, Christian

    2014-06-01

    People with Rett syndrome (RTT) have severe communicative difficulties. They have as well an immature brainstem that implies dysfunction of the autonomic nervous system. Music plays an important role in their life, is often used as a motivating tool in a variety of situations and activities, and caregivers are often clear about people with RTTs favourites. The aim of this study was to investigate physiological and emotional responses related to six different musical stimuli in people with RTT. The study included 29 participants with RTT who were referred to the Swedish Rett Center for medical brainstem assessment during the period 2006-2007. 11 children with a typical developmental pattern were used as comparison. A repeated measures design was used, and physiological data were collected from a neurophysiological brainstem assessment. The continuous dependent variables measured were Cardiac Vagal Tone (CVT), Cardiac Sensitivity to Baroreflex (CSB), Mean Arterial Blood Pressure (MAP) and the Coefficient of Variation of Mean Arterial Blood Pressure (MAP-CV). These parameters were used to categorise brainstem responses as parasympathetic (calming) response, sympathetic (activating) response, arousal (alerting) response and unclear response. The results showed that all participants responded to the musical stimuli, but not always in the expected way. It was noticeable that both people with and without RTT responded with an arousal to all musical stimuli to begin with. Even though the initial expressions sometimes changed after some time due to poor control functions of their brainstem, the present results are consistent with the possibility that the RTT participants' normal responses to music are intact. These findings may explain why music is so important for individuals with RTT throughout life.

  7. Hydrophilic-oleophobic stimuli-responsive materials and surfaces

    NASA Astrophysics Data System (ADS)

    Howarter, John A.

    Due to their high surface energy, hydrophilic surfaces are susceptible to contamination which is difficult to remove and often ruins the surface. Hydrophilic-oleophobic coatings have a diverse engineering potential including applications as self-cleaning surfaces, extended life anti-fog coatings, and environmental remediation in the selective filtration of oil-in-water mixtures. A successful design model for hydrophilic-oleophobic behavior has been developed using perfluorinated surfactants covalently bound to a surface. Within this design model, a variety of materials have been explored which the surfactants are covalently bound to a substrate; similarly, the surfactants may also be incorporated as a monomer into bulk copolymers. Surfactant based surfaces exhibited simultaneous hydrophilicity, necessary for anti-fogging, and oleophobicity, necessary for contamination resistance. The combination of these features rendered the surface as self-cleaning. Surfactant based brushes, composed of polyethylene glycol and perfluorinated constituents were grafted on to silica surfaces. The relationship between brush density and stimuli-responsiveness was determined by varying grafting conditions. The resultant surfaces were characterized with respect to chemical composition, brush thickness, and wetting behavior of water and hexadecane. Optimized surfaces exhibited stimuli-responsive behavior such that the surfaces will be wetted by water but not by oil. Surfactants were incorporated into random copolymers to create self-cleaning polymers which could be easily coated on to surfaces post-synthesis. Acrylic acid, methyl methacrylate, and hydroxyethyl methacrylate were used as comonomers; feed ratio was varied to establish compositional limits of stimuli-responsive behavior. Polymer composition dictated coating durability and self-cleaning performance as determined by water and hexadecane contact angle. The ability of select coatings to mitigate fogging was assessed in two

  8. Searching for optimal stimuli: ascending a neuron's response function.

    PubMed

    Koelling, Melinda Evrithiki; Nykamp, Duane Q

    2012-12-01

    Many methods used to analyze neuronal response assume that neuronal activity has a fundamentally linear relationship to the stimulus. However, some neurons are strongly sensitive to multiple directions in stimulus space and have a highly nonlinear response. It can be difficult to find optimal stimuli for these neurons. We demonstrate how successive linear approximations of neuronal response can effectively carry out gradient ascent and move through stimulus space towards local maxima of the response. We demonstrate search results for a simple model neuron and two models of a highly selective neuron. PMID:22580579

  9. Neural responses to smoking stimuli are influenced by smokers' attitudes towards their own smoking behaviour.

    PubMed

    Stippekohl, Bastian; Winkler, Markus H; Walter, Bertram; Kagerer, Sabine; Mucha, Ronald F; Pauli, Paul; Vaitl, Dieter; Stark, Rudolf

    2012-01-01

    An important feature of addiction is the high drug craving that may promote the continuation of consumption. Environmental stimuli classically conditioned to drug-intake have a strong motivational power for addicts and can elicit craving. However, addicts differ in the attitudes towards their own consumption behavior: some are content with drug taking (consonant users) whereas others are discontent (dissonant users). Such differences may be important for clinical practice because the experience of dissonance might enhance the likelihood to consider treatment. This fMRI study investigated in smokers whether these different attitudes influence subjective and neural responses to smoking stimuli. Based on self-characterization, smokers were divided into consonant and dissonant smokers. These two groups were presented smoking stimuli and neutral stimuli. Former studies have suggested differences in the impact of smoking stimuli depending on the temporal stage of the smoking ritual they are associated with. Therefore, we used stimuli associated with the beginning (BEGIN-smoking-stimuli) and stimuli associated with the terminal stage (END-smoking-stimuli) of the smoking ritual as distinct stimulus categories. Stimulus ratings did not differ between both groups. Brain data showed that BEGIN-smoking-stimuli led to enhanced mesolimbic responses (amygdala, hippocampus, insula) in dissonant compared to consonant smokers. In response to END-smoking-stimuli, dissonant smokers showed reduced mesocortical responses (orbitofrontal cortex, subcallosal cortex) compared to consonant smokers. These results suggest that smoking stimuli with a high incentive value (BEGIN-smoking-stimuli) are more appetitive for dissonant than consonant smokers at least on the neural level. To the contrary, smoking stimuli with low incentive value (END-smoking-stimuli) seem to be less appetitive for dissonant smokers than consonant smokers. These differences might be one reason why dissonant smokers

  10. Post-training re-exposure to fear conditioned stimuli enhances memory consolidation and biases rats toward the use of dorsolateral striatum-dependent response learning.

    PubMed

    Leong, Kah-Chung; Goodman, Jarid; Packard, Mark G

    2015-09-15

    In a dual-solution task that can be acquired using either hippocampus-dependent "place" or dorsolateral striatum-dependent "response" learning, emotional arousal induced by unconditioned stimuli (e.g. anxiogenic drug injections or predator odor exposure) biases rats toward response learning. In the present experiments emotionally-arousing conditioned stimuli were used to modulate the relative use of multiple memory systems. In Experiment 1, adult male Long-Evans rats initially received three standard fear-conditioning trials in which a tone (2 kHz, 75 dB) was paired with a brief electrical shock (1 mA, 2s). On day 2, the rats were trained in a dual-solution plus-maze task to swim from the same start arm (South) to a hidden escape platform always located in the same goal arm (East). Immediately following training, rats received post-training re-exposure to the fear-conditioned stimuli (i.e. tone and context) without shock. On day 3, the relative use of place or response learning was assessed on a probe trial in which rats were started from the opposite start arm (North). Post-training re-exposure to fear-conditioned stimuli produced preferential use of a response strategy. In Experiment 2, different rats received fear conditioning and were then trained in a single-solution task that required the use of response learning. Immediately following training, rats received post-training re-exposure to the fear-conditioned stimuli without shock. Re-exposure to fear-conditioned stimuli enhanced memory consolidation in the response learning task. Thus, re-exposure to fear-conditioned stimuli biases rats toward the use of dorsolateral striatum-dependent response learning and enhances memory consolidation of response learning.

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

    PubMed Central

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

    2016-01-01

    Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words “GREEN” or “RED” were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying “GREEN” or “RED” had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system. PMID:26958463

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

    PubMed

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

    2016-01-01

    Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words "GREEN" or "RED" were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying "GREEN" or "RED" had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system. PMID:26958463

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

    PubMed

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

    2016-01-01

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

  14. A brain-derived metric for preferred kinetic stimuli.

    PubMed

    Zeki, Semir; Stutters, Jonathan

    2012-02-01

    We here address the question of whether there is any correlation between subjective preference for simple configurations within a specific visual domain such as motion and strength of activity in visual areas in which that domain is emphasized. We prepared several distinctive patterns of dots in motion with various characteristics and asked humans to rate them according to their preference, before and while scanning the activity in their brains with functional magnetic resonance imaging. For simplicity, we restricted ourselves to motion in the fronto-parallel plane. Moving patterns produced activity in areas V1, V2, the V3 complex (V3, V3A, V3B) and V5, but only in areas V5, V3A/B and parietal cortex did the preferred kinetic patterns produce stronger activity when compared with the non-preferred ones. In addition, preferred patterns produced activity within field A1 of medial orbito-frontal cortex (mOFC), which is not otherwise activated by kinetic stimuli. Hence, for these areas, stronger neural activity correlated with subjective preference. We conclude that configurations of kinetic stimuli that are subjectively preferred correlate with stronger activity within early visual areas and within mOFC. This opens up the possibility of more detailed studies to relate subjective preferences to strength of activity in early visual areas and to relate activity in them to areas whose activity correlates with the subjective experience of beauty.

  15. Genetically engineered protein in hydrogels tailors stimuli-responsive characteristics

    NASA Astrophysics Data System (ADS)

    Ehrick, Jason D.; Deo, Sapna K.; Browning, Tyler W.; Bachas, Leonidas G.; Madou, Marc J.; Daunert, Sylvia

    2005-04-01

    Certain proteins undergo a substantial conformational change in response to a given stimulus. This conformational change can manifest in different manners and result in an actuation, that is, catalytic or signalling event, movement, interaction with other proteins, and so on. In all cases, the sensing-actuation process of proteins is initiated by a recognition event that translates into a mechanical action. Thus, proteins are ideal components for designing new nanomaterials that are intelligent and can perform desired mechanical actions in response to target stimuli. A number of approaches have been undertaken to mimic nature's sensing-actuating process. We now report a new hybrid material that integrates genetically engineered proteins within hydrogels capable of producing a stimulus-responsive action mechanism. The mechanical effect is a result of an induced conformational change and binding affinities of the protein in response to a stimulus. The stimuli-responsive hydrogel exhibits three specific swelling stages in response to various ligands offering additional fine-tuned control over a conventional two-stage swelling hydrogel. The newly prepared material was used in the sensing, and subsequent gating and transport of biomolecules across a polymer network, demonstrating its potential application in microfluidics and miniaturized drug-delivery systems.

  16. Nonconvulsive status epilepticus in rats: impaired responsiveness to exteroceptive stimuli.

    PubMed

    Mikulecká, A; Krsek, P; Hlinák, Z; Druga, R; Mares, P

    2000-12-20

    An animal model of human complex partial status epilepticus induced by lithium chloride and pilocarpine administration was developed in our laboratory. The objective of the study was to provide a detailed analysis of both ictal and postictal behavior and to quantify seizure-related morphological damage. In order to determine the animal's responsiveness to either visual or olfactory stimuli, adult male rats were submitted to the following behavioral paradigms: the object response test, the social interaction test, and the elevated plus-maze test. The rotorod test was used to evaluate motor performance. Two weeks after status epilepticus, brains were morphologically examined and quantification of the brain damage was performed. Profound impairment of behavior as well as responsiveness to exteroceptive stimuli correlated with the occurrence of epileptic EEG activity. When the epileptic EEG activity ceased, responsiveness of the pilocarpine-treated animals was renewed. However, remarkable morphological damage persisted in the cortical regions two weeks later. This experimental study provides support for the clinical evidence that even nonconvulsive epileptic activity may cause brain damage. We suggest that the model can be used for the study of both functional and morphological consequences of prolonged nonconvulsive seizures. PMID:11099755

  17. Food-associated stimuli enhance barrier properties of gastrointestinal mucus.

    PubMed

    Yildiz, Hasan M; Speciner, Lauren; Ozdemir, Cafer; Cohen, David E; Carrier, Rebecca L

    2015-06-01

    Orally delivered drugs and nutrients must diffuse through mucus to enter the circulatory system, but the barrier properties of mucus and their modulation by physiological factors are generally poorly characterized. The main objective of this study was to examine the impact of physicochemical changes occurring upon food ingestion on gastrointestinal (GI) mucus barrier properties. Lipids representative of postprandial intestinal contents enhanced mucus barriers, as indicated by a 10-142-fold reduction in the transport rate of 200 nm microspheres through mucus, depending on surface chemistry. Physiologically relevant increases in [Ca(2+)] resulted in a 2-4-fold reduction of transport rates, likely due to enhanced cross-linking of the mucus gel network. Reduction of pH from 6.5 to 3.5 also affected mucus viscoelasticity, reducing particle transport rates approximately 5-10-fold. Macroscopic visual observation and micro-scale lectin staining revealed mucus gel structural changes, including clumping into regions into which particles did not penetrate. Histological examination indicated food ingestion can prevent microsphere contact with and endocytosis by intestinal epithelium. Taken together, these results demonstrate that GI mucus barriers are significantly altered by stimuli associated with eating and potentially dosing of lipid-based delivery systems; these stimuli represent broadly relevant variables to consider upon designing oral therapies. PMID:25907034

  18. Spatio-temporal processing of tactile stimuli in autistic children.

    PubMed

    Wada, Makoto; Suzuki, Mayuko; Takaki, Akiko; Miyao, Masutomo; Spence, Charles; Kansaku, Kenji

    2014-08-07

    Altered multisensory integration has been reported in autism; however, little is known concerning how the autistic brain processes spatio-temporal information concerning tactile stimuli. We report a study in which a crossed-hands illusion was investigated in autistic children. Neurotypical individuals often experience a subjective reversal of temporal order judgments when their hands are stimulated while crossed, and the illusion is known to be acquired in early childhood. However, under those conditions where the somatotopic representation is given priority over the actual spatial location of the hands, such reversals may not occur. Here, we showed that a significantly smaller illusory reversal was demonstrated in autistic children than in neurotypical children. Furthermore, in an additional experiment, the young boys who had higher Autism Spectrum Quotient (AQ) scores generally showed a smaller crossed hands deficit. These results suggest that rudimentary spatio-temporal processing of tactile stimuli exists in autistic children, and the altered processing may interfere with the development of an external frame of reference in real-life situations.

  19. Empathic behavioral and physiological responses to dynamic stimuli in depression.

    PubMed

    Schneider, Daniel; Regenbogen, Christina; Kellermann, Thilo; Finkelmeyer, Andreas; Kohn, Nils; Derntl, Birgit; Schneider, Frank; Habel, Ute

    2012-12-30

    Major depressive disorder (MDD) is strongly linked to social withdrawal and interpersonal problems which characterize the disorder and further aggravate symptoms. Investigating the nature of impaired emotional-social functioning as a basis of interpersonal functioning in MDD has been widely restricted to static stimuli and behavioral emotion recognition accuracy. The present study aimed at examining higher order emotional processes, namely empathic responses and its components, emotion recognition accuracy and affective responses in 28 MDD patients and 28 healthy control participants. The dynamic stimulus material included 96 short video clips depicting actors expressing basic emotions by face, voice prosody, and sentence content. Galvanic skin conductance measurements revealed implicit processes in the multimethod assessment of empathy. Overall, patients displayed lower empathy, emotion accuracy, and affective response rates than controls. Autonomous arousal was higher in patients. A generalized emotion processing deficit is in line with the "emotional context insensitivity" (ECI) theory which proposes decreased overall responsiveness to emotional stimuli. The dissociation between hypo-reactivity in explicit and hyper-reactivity in implicit measures of emotion processing can be related to the "limbic-cortical dysregulation" model of depression. Our findings support the dissociation of autonomic and subjective emotional responses which may account for interpersonal as well as emotional deficits in depression. PMID:22560057

  20. Effects of vasoactive stimuli on blood flow to choroid plexus

    SciTech Connect

    Faraci, F.M.; Mayhan, W.G.; Williams, J.K.; Heistad, D.D. )

    1988-02-01

    The goal of this study was to examine effects of vasoactive stimuli on blood flow to choroid plexus. The authors used microspheres to measure blood flow to choroid plexus and cerebrum in anesthetized dogs and rabbits. A critical assumption of the microsphere method is that microspheres do not pass through arteriovenous shunts. Blood flow values obtained with simultaneous injection of 15- and 50-{mu}m microspheres were similar, which suggest that shunting of 15-{mu}m microspheres was minimal. Blood flow to choroid plexus under control conditions was 287 {plus minus} 26 (means {plus minus} SE) ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} in dogs and 385 {plus minus} 73 ml {center dot} min{sup {minus}1} 100 g{sup {minus}1} in rabbits. Consecutive measurements under control conditions indicated that values for blood flow are reproducible. Adenosine did not alter blood flow to cerebrum but increased blood flow to choroid plexus two- to threefold in dogs and rabbits. Norepinephrine and phenylephrine did not affect blood flow to choroid plexus and cerebrum but decreased blood flow to choroid plexus by {approx} 50%. The authors suggest that (1) the microsphere method provides reproducible valid measurements of blood flow to the choroid plexus in dogs and rabbits and (2) vasoactive stimuli may have profoundly different effects on blood flow to choroid plexus and cerebrum.

  1. Event-related desynchronization evoked by auditory stimuli.

    PubMed

    Krause, C M; Lang, H A; Laine, M; Helle, S I; Kuusisto, M J; Pörn, B

    1994-01-01

    Event-Related Desynchronization (ERD) and Synchronization (ERS) of several EEG alpha frequencies was studied in 19 subjects during the presentation of linguistic and/or melodic auditory stimuli. The stimulus length was 1300 msec (+/-100 msec) and the interstimulus interval was 2000 msec. A significant ERD was found during auditory stimulation in the 8-10 Hz and 10-12 Hz alpha frequency bands, and there were also significant differences in the spatiotemporal pattern of the ERD between these frequency bands. Significant ERD was elicited also in the 10-11 and 11-12 Hz frequency bands by auditory stimulation. There were no significant differences between these one-hertz frequency bands. The subjects were assigned to two analysis groups according to their individual alpha peak frequency (10-11 or 11-12 Hz) at rest. The ERD in these groups reached statistical significance and there were significant differences between the groups. The ERD of the two groups differed significantly also when their EEG data was studied in the 10-12 Hz frequency band. The results from this study show that ERD is not modality-specific, i.e., it can be elicited also by auditory stimuli. Moreover, they indicate that it is important to control over interindividual variation in the EEG when studying the ERD phenomenon.

  2. Crosslinked ionic polysaccharides for stimuli-sensitive drug delivery.

    PubMed

    Alvarez-Lorenzo, Carmen; Blanco-Fernandez, Barbara; Puga, Ana M; Concheiro, Angel

    2013-08-01

    Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems, particularly since they can be obtained in a well characterized and reproducible way from the natural sources. Ionic polysaccharides can be readily crosslinked to render hydrogel networks sensitive to a variety of internal and external variables, and thus suitable for switching drug release on-off through diverse mechanisms. Hybrids, composites and grafted polymers can reinforce the responsiveness and widen the range of stimuli to which polysaccharide-based systems can respond. This review analyzes the state of the art of crosslinked ionic polysaccharides as components of delivery systems that can regulate drug release as a function of changes in pH, ion nature and concentration, electric and magnetic field intensity, light wavelength, temperature, redox potential, and certain molecules (enzymes, illness markers, and so on). Examples of specific applications are provided. The information compiled demonstrates that crosslinked networks of ionic polysaccharides are suitable building blocks for developing advanced externally activated and feed-back modulated drug delivery systems.

  3. Simplification of olfactory stimuli in pseudo-gustatory displays.

    PubMed

    Narumi, Takuji; Miyaura, Masaaki; Tanikawa, Tomohiro; Hirose, Michitaka

    2014-04-01

    In this paper, we propose a technique that simplifies pseudo-gustatory systems by using the cross-modal effect between vision and olfaction to change only the visual and olfactory stimuli without altering the ingredients of the food. Conventional pseudo-gustatory simulations require one olfactory stimulus for each flavor. In contrast, we hypothesize that the cross-modal effect between vision and olfaction in a pseudo-gustatory presentation can be utilized to reduce the required number of olfactory stimuli, and verify this hypothesis using a pseudo-gustatory display with our proposed method. This pseudo-gustatory display uses the visual-olfactory cross-modal effect and the key scent components decided on the basis of similarity analysis of olfactory perception. We also investigate how users perceive the taste of a drink under various visual and olfactory conditions, both with and without the visual-olfactory interactions. Our results indicate that the cross-modal effect between vision and olfaction can effectively simplify pseudo-gustatory simulations.

  4. Healable thermoset polymer composite embedded with stimuli-responsive fibres

    PubMed Central

    Li, Guoqiang; Meng, Harper; Hu, Jinlian

    2012-01-01

    Severe wounds in biological systems such as human skin cannot heal themselves, unless they are first stitched together. Healing of macroscopic damage in thermoset polymer composites faces a similar challenge. Stimuli-responsive shape-changing polymeric fibres with outstanding mechanical properties embedded in polymers may be able to close macro-cracks automatically upon stimulation such as heating. Here, a stimuli-responsive fibre (SRF) with outstanding mechanical properties and supercontraction capability was fabricated for the purpose of healing macroscopic damage. The SRFs and thermoplastic particles (TPs) were incorporated into regular thermosetting epoxy for repeatedly healing macroscopic damages. The system works by mimicking self-healing of biological systems such as human skin, close (stitch) then heal, i.e. close the macroscopic crack through the thermal-induced supercontraction of the SRFs, and bond the closed crack through melting and diffusing of TPs at the crack interface. The healing efficiency determined using tapered double-cantilever beam specimens was 94 per cent. The self-healing process was reasonably repeatable. PMID:22896563

  5. Intensity perception. VIII. Loudness comparisons between different types of stimuli.

    PubMed

    Lim, J S; Rabinowtiz, W M; Braida, L D; Durlach, N I

    1977-11-01

    In this paper, we describe an extension of our preliminary theory of intensity resolution [Durlach and Braida, J. Acoust. Soc. Am. 46, 372-383 (1969)] to include loudness comparisons among different types of stimuli. The extended theory relates mean loudness matches to discrimination and provides a framework for the interpretation of results on the intrasubject variability of loudness comparisons. The predicted relation between mean loudness matches and discrimination is essentially the same as that proposed by Riesz [J. Acoust. Soc. Am. 5, 211-216 (1933)]. With regard to the variability of loudness comparisons, the extended model is essentially the same as the preliminary model except that a new term is included in the trace-mode memory variance to account for the dissimilarity of the stimuli being compared. The model is compared to some published data on loudness matching and discrimination and to some new data of our own on the variability of loudness comparisons obtained in a two-interval, roving-level, loudness-discrimination experiment. PMID:915119

  6. MEG brain activities reflecting affection for visual food stimuli.

    PubMed

    Kuriki, Shinya; Miyamura, Takahiro; Uchikawa, Yoshinori

    2010-01-01

    This study aimed to explore the modulation of alpha rhythm in response to food pictures with distinct affection values. We examined the method to discriminate subject's state, i.e., whether he/she liked the article of food or not, from MEG signals detected over the head. Pictures of familiar foods were used as affective stimuli, while those pictures with complementary color phase were used as non-affective stimuli. Alpha band signals in a narrow frequency window around the spectral peak of individual subjects were wavelet analyzed and phase-locked component to the stimulus onset was obtained as a complex number. The amplitude of the phase-locked component was averaged during 0-1 s after stimulus onset for 30 epochs in a measurement session and across 76 channels of MEG sensor. In statistical test of individual subjects, significant difference was found in the real part of the averaged phase-locked amplitude between the normal-color and reverse-color pictures. These results suggest that affective information processing of food pictures is reflected in the synchronized component of narrow band alpha rhythm. PMID:21096510

  7. Disruption of postural readaptation by inertial stimuli following space flight

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Paloski, W. H.; Reschke, M. F.; Igarashi, M.; Guedry, F.; Anderson, D. J.

    1999-01-01

    Postural instability (relative to pre-flight) has been observed in all shuttle astronauts studied upon return from orbital missions. Postural stability was more closely examined in four shuttle astronaut subjects before and after an 8 day orbital mission. Results of the pre- and post-flight postural stability studies were compared with a larger (n = 34) study of astronauts returning from shuttle missions of similar duration. Results from both studies indicated that inadequate vestibular feedback was the most significant sensory deficit contributing to the postural instability observed post flight. For two of the four IML-1 astronauts, post-flight postural instability and rate of recovery toward their earth-normal performance matched the performance of the larger sample. However, post-flight postural control in one returning astronaut was substantially below mean performance. This individual, who was within normal limits with respect to postural control before the mission, indicated that recovery to pre-flight postural stability was also interrupted by a post-flight pitch plane rotation test. A similar, though less extreme departure from the mean recovery trajectory was present in another astronaut following the same post-flight rotation test. The pitch plane rotation stimuli included otolith stimuli in the form of both transient tangential and constant centripetal linear acceleration components. We inferred from these findings that adaptation on orbit and re-adaptation on earth involved a change in sensorimotor integration of vestibular signals most likely from the otolith organs.

  8. Startle auditory stimuli enhance the performance of fast dynamic contractions.

    PubMed

    Fernandez-Del-Olmo, Miguel; Río-Rodríguez, Dan; Iglesias-Soler, Eliseo; Acero, Rafael M

    2014-01-01

    Fast reaction times and the ability to develop a high rate of force development (RFD) are crucial for sports performance. However, little is known regarding the relationship between these parameters. The aim of this study was to investigate the effects of auditory stimuli of different intensities on the performance of a concentric bench-press exercise. Concentric bench-presses were performed by thirteen trained subjects in response to three different conditions: a visual stimulus (VS); a visual stimulus accompanied by a non-startle auditory stimulus (AS); and a visual stimulus accompanied by a startle auditory stimulus (SS). Peak RFD, peak velocity, onset movement, movement duration and electromyography from pectoralis and tricep muscles were recorded. The SS condition induced an increase in the RFD and peak velocity and a reduction in the movement onset and duration, in comparison with the VS and AS condition. The onset activation of the pectoralis and tricep muscles was shorter for the SS than for the VS and AS conditions. These findings point out to specific enhancement effects of loud auditory stimulation on the rate of force development. This is of relevance since startle stimuli could be used to explore neural adaptations to resistance training.

  9. Startle Auditory Stimuli Enhance the Performance of Fast Dynamic Contractions

    PubMed Central

    Fernandez-Del-Olmo, Miguel; Río-Rodríguez, Dan; Iglesias-Soler, Eliseo; Acero, Rafael M.

    2014-01-01

    Fast reaction times and the ability to develop a high rate of force development (RFD) are crucial for sports performance. However, little is known regarding the relationship between these parameters. The aim of this study was to investigate the effects of auditory stimuli of different intensities on the performance of a concentric bench-press exercise. Concentric bench-presses were performed by thirteen trained subjects in response to three different conditions: a visual stimulus (VS); a visual stimulus accompanied by a non-startle auditory stimulus (AS); and a visual stimulus accompanied by a startle auditory stimulus (SS). Peak RFD, peak velocity, onset movement, movement duration and electromyography from pectoralis and tricep muscles were recorded. The SS condition induced an increase in the RFD and peak velocity and a reduction in the movement onset and duration, in comparison with the VS and AS condition. The onset activation of the pectoralis and tricep muscles was shorter for the SS than for the VS and AS conditions. These findings point out to specific enhancement effects of loud auditory stimulation on the rate of force development. This is of relevance since startle stimuli could be used to explore neural adaptations to resistance training. PMID:24489967

  10. Escape and aggregation responses of three echinoderms to conspecific stimuli.

    PubMed

    Campbell, A C; Coppard, S; D'Abreo, C; Tudor-Thomas, R

    2001-10-01

    In marine invertebrates, waterborne chemical stimuli mediate responses including prey detection and predator avoidance. Alarm and flight, in response to damaged conspecifics, have been reported in echinoderms, but the nature of the stimuli involved is not known. The responses of Asterias rubens Linnaeus, Psammechinus miliaris (Gmelin), and Echinus esculentus Linnaeus to conspecifics were tested in a choice chamber against a control of clean seawater (no stimulus). All three species showed statistically significant movement toward water conditioned by whole animals or homogenate of test epithelium. P. miliaris and E. esculentus displayed a statistically significant avoidance reaction, moving away from conspecific coelomic fluid, gut homogenate, and gonad homogenate. A. rubens was indifferent to conspecific coelomic fluid, pyloric cecum homogenate, and gonad homogenate but moved away from cardiac gut homogenate. P. miliaris was indifferent to gametes, but the other two species were significantly attracted to them. No species showed preference for one particular side of the chamber during trials to balance water flow. These echinoderms can distinguish between homogenates of conspecific tissues that might be exposed when a predator damages the test, and those that may emanate from the exterior surface during normal activities. PMID:11687389

  11. Effects of olfactory stimuli on urge reduction in smokers.

    PubMed

    Sayette, M A; Parrott, D J

    1999-05-01

    This study examined the possibility that exposure to olfactory stimuli can reduce self-reported urge to smoke. After an initial assessment of self-reported urge, nicotine-deprived smokers evaluated the pleasantness of a series of 8 odors. Facial expressions during odor presentations were coded with P. Ekman and W. V. Friesen's (1978a) Facial Action Coding System. After odor administration, participants were exposed to smoking cues. Next, participants were administered their most pleasant, least pleasant, or a control odor (water) and reported their urge to smoke. Results indicated that sniffing either a pleasant or unpleasant odor reduced reported urge to smoke relative to the control odor. Reported pleasantness of the odors did not differentially affect urge reduction. Odors eliciting negative-affect-related expressions, however, were less effective than odors that did not elicit negative-affect-related expressions in reducing reported urge. Results of this preliminary investigation provide support for the consideration of odor stimuli as an approach to craving reduction.

  12. Response of Morris-Lecar neurons to various stimuli

    NASA Astrophysics Data System (ADS)

    Wang, Hengtong; Wang, Longfei; Yu, Lianchun; Chen, Yong

    2011-02-01

    We studied the responses of three classes of Morris-Lecar neurons to sinusoidal inputs and synaptic pulselike stimuli with deterministic and random interspike intervals (ISIs). It was found that the responses of the output frequency of class 1 and 2 neurons showed similar evolution properties by varying input amplitudes and frequencies, whereas class 3 neuron exhibited substantially different properties. Specifically, class 1 and 2 neurons display complicated phase locking (p : q, p>q, denoting output action potentials per input spikes) in low-frequency sinusoidal input area when the input amplitude is above their threshold, but a class 3 neuron does not fire action potentials in this area even if the amplitude is much higher. In the case of the deterministic ISI synaptic injection, all the three classes of neurons oscillate spikes with an arbitrary small frequency. When increasing the input frequency (both sinusoidal and deterministic ISI synaptic inputs), all neurons display 1 : 1 phase locking, whereas the response frequency decreases even fall to zero in the high-frequency input area. When the random ISI synaptic pulselike stimuli are injected into the neurons, one can clearly see the low-pass filter behaviors from the return map. The output ISI distribution depends on the mean ISI of input train as well as the ISI variation. Such different responses of three classes of neurons result from their distinct dynamical mechanisms of action potential initiation. It was suggested that the intrinsic dynamical cellular properties are very important to neuron information processing.

  13. EEG Responses to Auditory Stimuli for Automatic Affect Recognition

    PubMed Central

    Hettich, Dirk T.; Bolinger, Elaina; Matuz, Tamara; Birbaumer, Niels; Rosenstiel, Wolfgang; Spüler, Martin

    2016-01-01

    Brain state classification for communication and control has been well established in the area of brain-computer interfaces over the last decades. Recently, the passive and automatic extraction of additional information regarding the psychological state of users from neurophysiological signals has gained increased attention in the interdisciplinary field of affective computing. We investigated how well specific emotional reactions, induced by auditory stimuli, can be detected in EEG recordings. We introduce an auditory emotion induction paradigm based on the International Affective Digitized Sounds 2nd Edition (IADS-2) database also suitable for disabled individuals. Stimuli are grouped in three valence categories: unpleasant, neutral, and pleasant. Significant differences in time domain domain event-related potentials are found in the electroencephalogram (EEG) between unpleasant and neutral, as well as pleasant and neutral conditions over midline electrodes. Time domain data were classified in three binary classification problems using a linear support vector machine (SVM) classifier. We discuss three classification performance measures in the context of affective computing and outline some strategies for conducting and reporting affect classification studies. PMID:27375410

  14. Large crowding zones in peripheral vision for briefly presented stimuli.

    PubMed

    Tripathy, Srimant Prasad; Cavanagh, Patrick; Bedell, Harold E

    2014-12-30

    When a target is flanked by distractors, it becomes more difficult to identify. In the periphery, this crowding effect extends over a wide range of target-flanker separations, called the spatial extent of interaction (EoI). A recent study showed that the EoI dramatically increases in size for short presentation durations (Chung & Mansfield, 2009). Here we investigate this duration-EoI relation in greater detail and show that (a) it holds even when visibility of the unflanked target is equated for different durations, (b) the function saturates for durations shorter than 30 to 80 ms, and (c) the largest EoIs represent a critical spacing greater than 50% of eccentricity. We also investigated the effect of same or different polarity for targets and flankers across different presentation durations. We found that EoIs for target and flankers having opposite polarity (one white, the other black) show the same temporal pattern as for same polarity stimuli, but are smaller at all durations by 29% to 44%. The observed saturation of the EoI for short-duration stimuli suggests that crowding follows the locus of temporal integration. Overall, the results constrain theories that map crowding zones to fixed spatial extents or to lateral connections of fixed length in the cortex.

  15. Response time to colored stimuli in the full visual field

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Dawson, L. M.; Galvan, T.; Reid, L. M.

    1975-01-01

    Peripheral visual response time was measured in seven dark adapted subjects to the onset of small (45' arc diam), brief (50 msec), colored (blue, yellow, green, red) and white stimuli imaged at 72 locations within their binocular field of view. The blue, yellow, and green stimuli were matched for brightness at about 2.6 sub log 10 units above their absolute light threshold, and they appeared at an unexpected time and location. These data were obtained to provide response time and no-response data for use in various design disciplines involving instrument panel layout. The results indicated that the retina possesses relatively concentric regions within each of which mean response time can be expected to be of approximately the same duration. These regions are centered near the fovea and extend farther horizontally than vertically. Mean foveal response time was fastest for yellow and slowest for blue. Three and one-half percent of the total 56,410 trials presented resulted in no-responses. Regardless of stimulus color, the lowest percentage of no-responses occurred within 30 deg arc from the fovea and the highest within 40 deg to 80 deg arc below the fovea.

  16. Pairwise agonist scanning predicts cellular signaling responses to combinatorial stimuli.

    PubMed

    Chatterjee, Manash S; Purvis, Jeremy E; Brass, Lawrence F; Diamond, Scott L

    2010-07-01

    Prediction of cellular response to multiple stimuli is central to evaluating patient-specific clinical status and to basic understanding of cell biology. Cross-talk between signaling pathways cannot be predicted by studying them in isolation and the combinatorial complexity of multiple agonists acting together prohibits an exhaustive exploration of the complete experimental space. Here we describe pairwise agonist scanning (PAS), a strategy that trains a neural network model based on measurements of cellular responses to individual and all pairwise combinations of input signals. We apply PAS to predict calcium signaling responses of human platelets in EDTA-treated plasma to six different agonists (ADP, convulxin, U46619, SFLLRN, AYPGKF and PGE(2)) at three concentrations (0.1, 1 and 10 x EC(50)). The model predicted responses to sequentially added agonists, to ternary combinations of agonists and to 45 different combinations of four to six agonists (R = 0.88). Furthermore, we use PAS to distinguish between the phenotypic responses of platelets from ten donors. Training neural networks with pairs of stimuli across the dose-response regime represents an efficient approach for predicting complex signal integration in a patient-specific disease milieu. PMID:20562863

  17. Contrast polarity preservation's role in perception: explained and unexplained stimuli.

    PubMed

    McCormick, Meghan C; Hon, Alice J; Huang, Abigail E; Altschuler, Eric L

    2012-01-01

    Roncato and Casco (2003, Perception & psychophysics 65 1252-1272) had shown that in situations where the Gestalt principle of good continuity is put into conflict with preservation of contrast polarity (CP) the perception that preserves CP prevails. Parlangeli and Roncato (2010, Perception 39 255-259) have studied this question of preservation of CP more closely and have added an addendum to the rule. They have used stimuli consisting of a checkerboard of perpendicularly arranged rectangular bricks (white, gray, or black) and draughtsmen white, gray, or black disks placed at the corners of the bricks. This study has caused them to add an addendum to the rule of CP-preserved path-conjunction binding: if there are two contour completions that preserve the CP, the one with the higher contrast will prevail. Parlangeli and Roncato find that, for certain shades of the disks and bricks, the perpendicular lines of the checkerboard appear strikingly to be slanted or undulating. Here we consider all possible arrangements of relative magnitudes of checkerboards consisting of bricks of two different shades and disks of two shades as well, as such arrangements with widely varying differences in the magnitude of brightness. We have found a number of cases where the perception is not explained by the rule and addendum of Roncato and Casco, and Parlangeli and Roncato, and a case where preservation of "distant" as well as local CP plays a role in perception. The previously known cases, and the new exceptional unexplained stimuli we have found, warrant further study.

  18. Task Attention Facilitates Learning of Task-Irrelevant Stimuli

    PubMed Central

    Huang, Tsung-Ren; Watanabe, Takeo

    2012-01-01

    Attention plays a fundamental role in visual learning and memory. One highly established principle of visual attention is that the harder a central task is, the more attentional resources are used to perform the task and the smaller amount of attention is allocated to peripheral processing because of limited attention capacity. Here we show that this principle holds true in a dual-task setting but not in a paradigm of task-irrelevant perceptual learning. In Experiment 1, eight participants were asked to identify either bright or dim number targets at the screen center and to remember concurrently presented scene backgrounds. Their recognition performances for scenes paired with dim/hard targets were worse than those for scenes paired with bright/easy targets. In Experiment 2, eight participants were asked to identify either bright or dim letter targets at the screen center while a task-irrelevant coherent motion was concurrently presented in the background. After five days of training on letter identification, participants improved their motion sensitivity to the direction paired with hard/dim targets improved but not to the direction paired with easy/bright targets. Taken together, these results suggest that task-irrelevant stimuli are not subject to the attentional control mechanisms that task-relevant stimuli abide. PMID:22563424

  19. EEG Responses to Auditory Stimuli for Automatic Affect Recognition.

    PubMed

    Hettich, Dirk T; Bolinger, Elaina; Matuz, Tamara; Birbaumer, Niels; Rosenstiel, Wolfgang; Spüler, Martin

    2016-01-01

    Brain state classification for communication and control has been well established in the area of brain-computer interfaces over the last decades. Recently, the passive and automatic extraction of additional information regarding the psychological state of users from neurophysiological signals has gained increased attention in the interdisciplinary field of affective computing. We investigated how well specific emotional reactions, induced by auditory stimuli, can be detected in EEG recordings. We introduce an auditory emotion induction paradigm based on the International Affective Digitized Sounds 2nd Edition (IADS-2) database also suitable for disabled individuals. Stimuli are grouped in three valence categories: unpleasant, neutral, and pleasant. Significant differences in time domain domain event-related potentials are found in the electroencephalogram (EEG) between unpleasant and neutral, as well as pleasant and neutral conditions over midline electrodes. Time domain data were classified in three binary classification problems using a linear support vector machine (SVM) classifier. We discuss three classification performance measures in the context of affective computing and outline some strategies for conducting and reporting affect classification studies. PMID:27375410

  20. Spatio-temporal processing of tactile stimuli in autistic children

    PubMed Central

    Wada, Makoto; Suzuki, Mayuko; Takaki, Akiko; Miyao, Masutomo; Spence, Charles; Kansaku, Kenji

    2014-01-01

    Altered multisensory integration has been reported in autism; however, little is known concerning how the autistic brain processes spatio-temporal information concerning tactile stimuli. We report a study in which a crossed-hands illusion was investigated in autistic children. Neurotypical individuals often experience a subjective reversal of temporal order judgments when their hands are stimulated while crossed, and the illusion is known to be acquired in early childhood. However, under those conditions where the somatotopic representation is given priority over the actual spatial location of the hands, such reversals may not occur. Here, we showed that a significantly smaller illusory reversal was demonstrated in autistic children than in neurotypical children. Furthermore, in an additional experiment, the young boys who had higher Autism Spectrum Quotient (AQ) scores generally showed a smaller crossed hands deficit. These results suggest that rudimentary spatio-temporal processing of tactile stimuli exists in autistic children, and the altered processing may interfere with the development of an external frame of reference in real-life situations. PMID:25100146

  1. Dynamic Stimuli And Active Processing In Human Visual Perception

    NASA Astrophysics Data System (ADS)

    Haber, Ralph N.

    1990-03-01

    Theories of visual perception traditionally have considered a static retinal image to be the starting point for processing; and has considered processing both to be passive and a literal translation of that frozen, two dimensional, pictorial image. This paper considers five problem areas in the analysis of human visually guided locomotion, in which the traditional approach is contrasted to newer ones that utilize dynamic definitions of stimulation, and an active perceiver: (1) differentiation between object motion and self motion, and among the various kinds of self motion (e.g., eyes only, head only, whole body, and their combinations); (2) the sources and contents of visual information that guide movement; (3) the acquisition and performance of perceptual motor skills; (4) the nature of spatial representations, percepts, and the perceived layout of space; and (5) and why the retinal image is a poor starting point for perceptual processing. These newer approaches argue that stimuli must be considered as dynamic: humans process the systematic changes in patterned light when objects move and when they themselves move. Furthermore, the processing of visual stimuli must be active and interactive, so that perceivers can construct panoramic and stable percepts from an interaction of stimulus information and expectancies of what is contained in the visual environment. These developments all suggest a very different approach to the computational analyses of object location and identification, and of the visual guidance of locomotion.

  2. Multiple sensitivity to chemical stimuli in single human taste papillae.

    PubMed

    Bealer, S L; Smith, D V

    1975-06-01

    The sensitivities of 15 human fungiform papillae were tested using a 5-alternative forced-choice procedure. Subjects were aked to recognize which of the following stimuli was presented to a papilla on each of 250 trials: 5.0 M NaCl, 0.5 N citric acid, 1.0 M quinine hydrochloride, and distilled H2O. Solution droplets were delivered to individual papillae from 0.5 mm diameter platinum wire loops. Based on each subject's responses to distilled H2O, corrections were made for individual response biases. Of the papillae tested, 33 percent responded to all four compounds, 33 percent to three, none to only two, 20 percent to only one, and 13 percent to none of the chemical stimuli. These results are contradictory to earlier work, in which it was suggested that taste quality is encoded by chemically specific papillae, but are consistent with the electrophysiological data suggesting multiple sensitivity of mammalian gustatory receptor cells and first-order neurons. The data suggested that the narrow range of sensitivity reported by von Békésy [2] was determined by the reciprocal relationship between the size of the stimulated area and the concentration necessary to elicit a threshold sensation. PMID:1187834

  3. Nanoparticle role on the repeatability of stimuli-responsive nanocomposites.

    PubMed

    Ahn, Sungsook; Lee, Sang Joon

    2014-10-15

    Repeatability of the responsiveness with time is one important concern for effective durable functions of stimuli-responsive materials. Although the increase in the yield and tensile strength of the hybrid composite materials by nanoparticle (NP) incorporation has been reported, exact NP effect on stimuli-responsiveness is rarely reported. In this study, a set of nanoscale actuating system is demonstrated by a thermo-sensitive process operated by polyethylene glycol (PEG) linked by gold nanoparticle (AuNP). This designed nanocomposite exclusively provides an artificial on/off gate function for selective passages of permeate molecules. The results demonstrate high repetition efficiency with sharp responding in a timely manner. In terms of the morphology changes induced by repeated swelling-deswelling mechanics, the nanocomposite exhibits phase separation between AuNP clusters and PEG domains. This leads to a delay in responsiveness in a cumulative way with time. Acting as stable junction points in the nanocomposite network structures, the incorporated AuNPs contribute to maintain repeatability in responsiveness. This study contributes to new-concept smart material design and fundamental understanding on the hybrid nanomaterials for various applications in terms of a dynamic mechanical behavior.

  4. Reconstruction of Sensory Stimuli Encoded with Integrate-and-Fire Neurons with Random Thresholds

    PubMed Central

    Lazar, Aurel A.; Pnevmatikakis, Eftychios A.

    2013-01-01

    We present a general approach to the reconstruction of sensory stimuli encoded with leaky integrate-and-fire neurons with random thresholds. The stimuli are modeled as elements of a Reproducing Kernel Hilbert Space. The reconstruction is based on finding a stimulus that minimizes a regularized quadratic optimality criterion. We discuss in detail the reconstruction of sensory stimuli modeled as absolutely continuous functions as well as stimuli with absolutely continuous first-order derivatives. Reconstruction results are presented for stimuli encoded with single as well as a population of neurons. Examples are given that demonstrate the performance of the reconstruction algorithms as a function of threshold variability. PMID:24077610

  5. [The P300-based brain-computer interface: presentation of the complex "flash + movement" stimuli].

    PubMed

    Ganin, I P; Kaplan, A Ia

    2014-01-01

    The P300 based brain-computer interface requires the detection of P300 wave of brain event-related potentials. Most of its users learn the BCI control in several minutes and after the short classifier training they can type a text on the computer screen or assemble an image of separate fragments in simple BCI-based video games. Nevertheless, insufficient attractiveness for users and conservative stimuli organization in this BCI may restrict its integration into real information processes control. At the same time initial movement of object (motion-onset stimuli) may be an independent factor that induces P300 wave. In current work we checked the hypothesis that complex "flash + movement" stimuli together with drastic and compact stimuli organization on the computer screen may be much more attractive for user while operating in P300 BCI. In 20 subjects research we showed the effectiveness of our interface. Both accuracy and P300 amplitude were higher for flashing stimuli and complex "flash + movement" stimuli compared to motion-onset stimuli. N200 amplitude was maximal for flashing stimuli, while for "flash + movement" stimuli and motion-onset stimuli it was only a half of it. Similar BCI with complex stimuli may be embedded into compact control systems requiring high level of user attention under impact of negative external effects obstructing the BCI control.

  6. Cell biology and EMF safety standards.

    PubMed

    Blank, Martin

    2015-01-01

    Living cells react defensively and start to synthesize stress proteins when exposed to potentially harmful stimuli. Electromagnetic fields (EMF) are among the many different environmental stimuli that initiate stress protein synthesis. Although there is greater energy transfer and heating due to EMF at higher frequencies, there is no greater stress response. The cellular stress response is far more sensitive to EMF than to an increase in temperature. It should be obvious that an EMF safety standard should be based on the more sensitive, natural biological response.

  7. Late Positive Potential ERP Responses to Social and Nonsocial Stimuli in Youth with Autism Spectrum Disorder.

    PubMed

    Benning, Stephen D; Kovac, Megan; Campbell, Alana; Miller, Stephanie; Hanna, Eleanor K; Damiano, Cara R; Sabatino-DiCriscio, Antoinette; Turner-Brown, Lauren; Sasson, Noah J; Aaron, Rachel V; Kinard, Jessica; Dichter, Gabriel S

    2016-09-01

    We examined the late positive potential (LPP) event related potential in response to social and nonsocial stimuli from youths 9 to 19 years old with (n = 35) and without (n = 34) ASD. Social stimuli were faces with positive expressions and nonsocial stimuli were related to common restricted interests in ASD (e.g., electronics, vehicles, etc.). The ASD group demonstrated relatively smaller LPP amplitude to social stimuli and relatively larger LPP amplitude to nonsocial stimuli. There were no group differences in subjective ratings of images, and there were no significant correlations between LPP amplitude and ASD symptom severity within the ASD group. LPP results suggest blunted motivational responses to social stimuli and heightened motivational responses to nonsocial stimuli in youth with ASD. PMID:27344337

  8. The Motivating Effect of Antecedent Stimuli on the Web Shop: A Conjoint Analysis of the Impact of Antecedent Stimuli at the Point of Online Purchase

    ERIC Educational Resources Information Center

    Fagerstrom, Asle

    2010-01-01

    This article introduces the concept of motivating operation (MO) to the field of online consumer research. A conjoint analysis was conducted to assess the motivating impact of antecedent stimuli on online purchasing. Stimuli tested were in-stock status, price, other customers' reviews, order confirmation procedures, and donation to charity. The…

  9. Perceived Sexual Orientation Based on Vocal and Facial Stimuli Is Linked to Self-Rated Sexual Orientation in Czech Men

    PubMed Central

    Valentova, Jaroslava Varella; Havlíček, Jan

    2013-01-01

    Previous research has shown that lay people can accurately assess male sexual orientation based on limited information, such as face, voice, or behavioral display. Gender-atypical traits are thought to serve as cues to sexual orientation. We investigated the presumed mechanisms of sexual orientation attribution using a standardized set of facial and vocal stimuli of Czech men. Both types of stimuli were rated for sexual orientation and masculinity-femininity by non-student heterosexual women and homosexual men. Our data showed that by evaluating vocal stimuli both women and homosexual men can judge sexual orientation of the target men in agreement with their self-reported sexual orientation. Nevertheless, only homosexual men accurately attributed sexual orientation of the two groups from facial images. Interestingly, facial images of homosexual targets were rated as more masculine than heterosexual targets. This indicates that attributions of sexual orientation are affected by stereotyped association between femininity and male homosexuality; however, reliance on such cues can lead to frequent misjudgments as was the case with the female raters. Although our study is based on a community sample recruited in a non-English speaking country, the results are generally consistent with the previous research and thus corroborate the validity of sexual orientation attributions. PMID:24358180

  10. Hypoosmotic stimuli activate a chloride conductance in rat taste cells.

    PubMed

    Gilbertson, Timothy A

    2002-05-01

    The oral cavity is subjected to a wide range of osmotic conditions, yet little is known about how solution osmolarity affects performance of the gustatory system. In order to elucidate the mechanism by which hypoosmotic stimuli affect the peripheral taste system, I have attempted to characterize the effects of hypoosmotic stimuli on individual rat taste receptor cells (TRCs) using whole-cell patch clamp recording. Currents elicited in response to voltage ramps (-90 to +60 mV) were recorded in control saline and in solutions varying only in osmolarity (-30, -60 and -90 mOsm). In roughly two-thirds of cells, hypoosmotic solutions (230 mOsm) caused a 15% increase in cell capacitance and activated a reversible conductance that exhibited marked adaptation in the continued presence of the stimulus. Similar responses could be elicited in taste cells from taste buds in the foliate and vallate papillae, the soft palate, the nasopharynx and the epiglottis. Ion substitution experiments were consistent with the interpretation that the predominant ion carried through these apparent volume- or stretch-activated channels was Cl(-) under normal conditions. Reversal potentials for the hypoosmotic-induced current closely matched those predicted by the Goldman-Hodgkin-Katz constant field equation for a Cl(-) conductance. The relative permeability sequence of the hypoosmotic-activated current in TRCs was thiocyanate(-) > or = l(-) > or = Br(-) > Cl(-) > or = F(-) > or = isethionate(-) > gluconate(-). Pharmacological experiments revealed that this Cl(-) conductance was inhibited by 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid and 5-nitro-3-(3-phenyl-propylamino)benzoic acid (EC(50) = 1.3 and 4.6 microM, respectively), but not by CdCl(2) (300 microM) nor GdCl(3) (200 microM). I hypothesize that this hypoosmotic-activated Cl(-) conductance, which is similar to the well-characterized swelling-activated Cl(-) current, may contribute to volume regulation and could represent the

  11. Preliminary results of the PreViBOSS project: description of the fog life cycle by ground-based and satellite observation

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Jolivet, Dominique; Dupont, Jean-Charles; Haeffelin, Martial; Burnet, Frédéric

    2012-11-01

    The instrument set-up designed by the PreViBOSS project for the ParisFog field campaign is suitable to sound microphysical properties of droplets and interstitial aerosols during developed fog in a semi-urban environment. Developed fog is defined as LWC < 7 mg m-3 and the temperature vertical gradient over 30 m, ΔT, smaller than 0.04 K/m. Visibility averaged over November 2011 is 385+/-340 m (with rare values larger than 1000 m), and month average of LWC is 60+/-60 mg m-3. The droplet effective radius decreases from 14 to 4 μm when the number concentration increases from less than 10 to 220 cm-3. Particle extinction coefficient is computed by Mie theory applied on size distribution observed during developed fog in ambient conditions by both PALAS WELAS and DMT FM100. Comparison with particle extinction coefficient directly measured by the Degreanne DF20 visibilimeter demonstrates satisfying agreement, within combined uncertainties. Ratio of computed over measured particle extinction coefficient is 1.15+/-0.35. Visibility smaller than 1000 m at 3 m above ground level is observed not only during developed fog but also during shallow fog, which presents a significant vertical gradient, as ΔT > 0.4 K/m. In this case, LWC is highly variable and may be observed below 7 mg m-3. The consequent month average of LWC is 30+/-80 mg m-3. The optical counters miss large droplets significantly contributing to extinction in shallow fogs. Consequently, it is not possible to reproduce with satisfaction the particle extinction coefficient in shallow fog. Fog type may be distinguished by association of groundbased visibilimeter and MSG/SEVIRI. When clear-sky is given by EUMETSAT/NWCSAF cloud type product while visibility is observed smaller than 1000 m at SIRTA, in 75% cases a shallow fog occurs, and in other cases, horizontal heterogeneity characterises the developed fog within the SIRTA pixel, as during the dissipation phase. Moreover, consistently, low and very low clouds are

  12. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Percival, Will J.; Cuesta, Antonio J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Schlegel, David J.; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Vargas Magaña, Mariana; Zhao, Gong-Bo

    2016-08-01

    We present an anisotropic analysis of the baryon acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361 762 galaxies with an effective redshift of zLOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of zCMASS = 0.57. We extract the BAO peak position from the monopole power-spectrum moment, α0, and from the μ2 moment, α2, where μ is the cosine of the angle to the line of sight. The μ2-moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ2-moment, which are related to radial and angular shifts in scale. We report H(zLOWZ)rs(zd) = (11.60 ± 0.60) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.66 ± 0.16 with a cross-correlation coefficient of r_{HD_A}=0.41, for the LOWZ sample; and H(zCMASS)rs(zd) = (14.56 ± 0.37) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.42 ± 0.13 with a cross-correlation coefficient of r_{HD_A}=0.47, for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same data set (Cuesta et al. 2016, companion paper) and report the consensus values: H(zLOWZ)rs(zd) = (11.63 ± 0.69) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.67 ± 0.15 with r_{HD_A}=0.35 for the LOWZ sample; H(zCMASS)rs(zd) = (14.67 ± 0.42) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.47 ± 0.12 with r_{HD_A}=0.52 for the CMASS sample.

  13. The Sydney Multisite Intervention of LaughterBosses and ElderClowns (SMILE) study: cluster randomised trial of humour therapy in nursing homes

    PubMed Central

    Low, Lee-Fay; Brodaty, Henry; Goodenough, Belinda; Spitzer, Peter; Bell, Jean-Paul; Fleming, Richard; Casey, Anne-Nicole; Liu, Zhixin; Chenoweth, Lynn

    2013-01-01

    Objectives To determine whether humour therapy reduces depression (primary outcome), agitation and behavioural disturbances and improves social engagement and quality-of-life in nursing home residents. Design The Sydney Multisite Intervention of LaughterBosses and ElderClowns study was a single-blind cluster randomised controlled trial of humour therapy. Setting 35 Sydney nursing homes. Participants All eligible residents within geographically defined areas within each nursing home were invited to participate. Intervention Professional ‘ElderClowns’ provided 9–12 weekly humour therapy sessions, augmented by resident engagement by trained staff ‘LaughterBosses’. Controls received usual care. Measurements Depression scores on the Cornell Scale for Depression in Dementia, agitation scores on the Cohen-Mansfield Agitation Inventory, behavioural disturbance scores on the Neuropsychiatric Inventory, social engagement scores on the withdrawal subscale of Multidimensional Observation Scale for Elderly Subjects, and self-rated and proxy-rated quality-of-life scores on a health-related quality-of-life tool for dementia, the DEMQOL. All outcomes were measured at the participant level by researchers blind to group assignment. Randomisation Sites were stratified by size and level of care then assigned to group using a random number generator. Results Seventeen nursing homes (189 residents) received the intervention and 18 homes (209 residents) received usual care. Groups did not differ significantly over time on the primary outcome of depression, or on behavioural disturbances other than agitation, social engagement and quality of life. The secondary outcome of agitation was significantly reduced in the intervention group compared with controls over 26 weeks (time by group interaction adjusted for covariates: p=0.011). The mean difference in change from baseline to 26 weeks in Blom-transformed agitation scores after adjustment for covariates was 0.17 (95% CI 0

  14. Comparisons of memory for nonverbal auditory and visual sequential stimuli.

    PubMed

    McFarland, D J; Cacace, A T

    1995-01-01

    Properties of auditory and visual sensory memory were compared by examining subjects' recognition performance of randomly generated binary auditory sequential frequency patterns and binary visual sequential color patterns within a forced-choice paradigm. Experiment 1 demonstrated serial-position effects in auditory and visual modalities consisting of both primacy and recency effects. Experiment 2 found that retention of auditory and visual information was remarkably similar when assessed across a 10s interval. Experiments 3 and 4, taken together, showed that the recency effect in sensory memory is affected more by the type of response required (recognition vs. reproduction) than by the sensory modality employed. These studies suggest that auditory and visual sensory memory stores for nonverbal stimuli share similar properties with respect to serial-position effects and persistence over time.

  15. Impaired Autonomic Responses to Emotional Stimuli in Autoimmune Limbic Encephalitis

    PubMed Central

    Schröder, Olga; Schriewer, Elisabeth; Golombeck, Kristin S.; Kürten, Julia; Lohmann, Hubertus; Schwindt, Wolfram; Wiendl, Heinz; Bruchmann, Maximilian; Melzer, Nico; Straube, Thomas

    2015-01-01

    Limbic encephalitis (LE) is an autoimmune-mediated disorder that affects structures of the limbic system, in particular, the amygdala. The amygdala constitutes a brain area substantial for processing of emotional, especially fear-related signals. The amygdala is also involved in neuroendocrine and autonomic functions, including skin conductance responses (SCRs) to emotionally arousing stimuli. This study investigates behavioral and autonomic responses to discrete emotion evoking and neutral film clips in a patient suffering from LE associated with contactin-associated protein-2 (CASPR2) antibodies as compared to a healthy control group. Results show a lack of SCRs in the patient while watching the film clips, with significant differences compared to healthy controls in the case of fear-inducing videos. There was no comparable impairment in behavioral data (emotion report, valence, and arousal ratings). The results point to a defective modulation of sympathetic responses during emotional stimulation in patients with LE, probably due to impaired functioning of the amygdala. PMID:26648907

  16. Rationally designed gibbous stimuli-responsive colloidal nanoparticles.

    PubMed

    Lu, Chunliang; Urban, Marek

    2015-03-24

    Multiphase colloidal copolymer nanoparticles, if properly designed, offer a number of unique properties and well-documented technological opportunities for drug delivery, nanolithography, high surface area colloidal crystals, or hollow nanoparticles, to name just a few. Using a simple free radical polymerization process, we synthesized copolymer nanoparticles with controlled stimuli-responsive phase-separated gibbosities. The topography of the gibbous phase can be controlled by the copolymer composition and polymerization conditions. When pH-sensitive monomers were copolymerized onto surface bulges, pH changes resulted in localized gibbous phase dimensional changes. Facilitated by monomer diffusion into interfacial particle seed solution regions, localized polymerization near the surface is responsible for the formation of phase-separated gibbous topographies. This general approach may offer a number of possibilities for controllable design of ordered heterogeneous copolymer morphologies for a variety of applications.

  17. Stimuli-Responsive Gold Nanoparticles for Cancer Diagnosis and Therapy

    PubMed Central

    Tian, Li; Lu, Linfeng; Qiao, Yang; Ravi, Saisree; Salatan, Ferandre; Melancon, Marites P.

    2016-01-01

    An emerging concept is that cancers strongly depend on both internal and external signals for growth and invasion. In this review, we will discuss pathological and physical changes in the tumor microenvironment and how these changes can be exploited to design gold nanoparticles for cancer diagnosis and therapy. These intrinsic changes include extracellular and intracellular pH, extracellular matrix enzymes, and glutathione concentration. External stimuli include the application of laser, ultrasound and X-ray. The biology behind these changes and the chemistry behind the responding mechanisms to these changes are reviewed. Examples of recent in vitro and in vivo studies are also presented, and the clinical implications of these findings are discussed.

  18. The relativity of time perception produced by facial emotion stimuli.

    PubMed

    Lee, Kwang-Hyuk; Seelam, Kalyan; O'Brien, Tom

    2011-12-01

    We systematically examined the impact of emotional stimuli on time perception in a temporal reproduction paradigm where participants reproduced the duration of a facial emotion stimulus using an oval-shape stimulus or vice versa. Experiment 1 asked participants to reproduce the duration of an angry face (or the oval) presented for 2,000 ms. Experiment 2 included a range of emotional expressions (happy, sad, angry, and neutral faces as well as the oval stimulus) presented for different durations (500, 1,500, and 2,000 ms). We found that participants over-reproduced the durations of happy and sad faces using the oval stimulus. By contrast, there was a trend of under-reproduction when the duration of the oval stimulus was reproduced using the angry face. We suggest that increased attention to a facial emotion produces the relativity of time perception.

  19. Massively parallel neural encoding and decoding of visual stimuli.

    PubMed

    Lazar, Aurel A; Zhou, Yiyin

    2012-08-01

    The massively parallel nature of video Time Encoding Machines (TEMs) calls for scalable, massively parallel decoders that are implemented with neural components. The current generation of decoding algorithms is based on computing the pseudo-inverse of a matrix and does not satisfy these requirements. Here we consider video TEMs with an architecture built using Gabor receptive fields and a population of Integrate-and-Fire neurons. We show how to build a scalable architecture for video Time Decoding Machines using recurrent neural networks. Furthermore, we extend our architecture to handle the reconstruction of visual stimuli encoded with massively parallel video TEMs having neurons with random thresholds. Finally, we discuss in detail our algorithms and demonstrate their scalability and performance on a large scale GPU cluster. PMID:22397951

  20. Coaxial nanotubes of stimuli responsive polymers with tunable release kinetics.

    PubMed

    Armagan, Efe; Ozaydin Ince, Gozde

    2015-11-01

    Stimuli responsive polymeric (SRP) nanotubes have great potential as nanocarriers of macromolecules due to their large surface areas and release mechanisms that can be activated externally. In this work, we demonstrate vapor phase synthesis of coaxial nanotubes with layers of different SRP polymers for improved release kinetics. Temperature responsive poly(N-isopropylacrylamide) (pNIPAAm), pH responsive poly(methacrylic acid) (pMAA) and poly(hydroxyethyl methacrylate) (pHEMA) are used to fabricate the responsive coaxial nanotubes and the phloroglucinol dye is used as the model molecule to study the release kinetics. Fastest release is observed with single layer pNIPAAm nanotubes with rates of 0.134 min(-1), whereas introducing pHEMA or pMAA as inner layers slows down the release, enabling tuning of the response. Furthermore, repeating the release studies multiple times shows that the release rates remain similar after each run, confirming the stability of the nanotubes.

  1. What boxing-related stimuli reveal about response behaviour.

    PubMed

    Ottoboni, Giovanni; Russo, Gabriele; Tessari, Alessia

    2015-01-01

    When two athletes meet inside the ropes of the boxing ring to fight, their cognitive systems have to respond as quickly as possible to a manifold of stimuli to assure victory. In the present work, we studied the pre-attentive mechanisms, which form the basis of an athlete's ability in reacting to an opponent's punches. Expert boxers, beginner boxers and people with no experience of boxing performed a Simon-like task where they judged the colour of the boxing gloves worn by athletes in attack postures by pressing two lateralised keys. Although participants were not instructed to pay attention to the direction of the punches, beginner boxers' responses resembled a defence-related pattern, expert boxers' resembled counterattacks, whereas non-athletes' responses were not influenced by the unrelated task information. Results are discussed in the light of an expertise-related action simulation account. PMID:25385452

  2. Combinatorial code governing cellular responses to complex stimuli

    PubMed Central

    Cappuccio, Antonio; Zollinger, Raphaël; Schenk, Mirjam; Walczak, Aleksandra; Servant, Nicolas; Barillot, Emmanuel; Hupé, Philippe; Modlin, Robert L.; Soumelis, Vassili

    2015-01-01

    Cells adapt to their environment through the integration of complex signals. Multiple signals can induce synergistic or antagonistic interactions, currently considered as homogenous behaviours. Here, we use a systematic theoretical approach to enumerate the possible interaction profiles for outputs measured in the conditions 0 (control), signals X, Y, X+Y. Combinatorial analysis reveals 82 possible interaction profiles, which we biologically and mathematically grouped into five positive and five negative interaction modes. To experimentally validate their use in living cells, we apply an original computational workflow to transcriptomics data of innate immune cells integrating physiopathological signal combinations. Up to 9 of the 10 defined modes coexisted in context-dependent proportions. Each interaction mode was preferentially used in specific biological pathways, suggesting a functional role in the adaptation to multiple signals. Our work defines an exhaustive map of interaction modes for cells integrating pairs of physiopathological and pharmacological stimuli. PMID:25896517

  3. Population coding of affect across stimuli, modalities and individuals

    PubMed Central

    Chikazoe, Junichi; Lee, Daniel H.; Kriegeskorte, Nikolaus; Anderson, Adam K.

    2014-01-01

    It remains unclear how the brain represents external objective sensory events alongside our internal subjective impressions of them—affect. Representational mapping of population level activity evoked by complex scenes and basic tastes uncovered a neural code supporting a continuous axis of pleasant-to-unpleasant valence. This valence code was distinct from low-level physical and high-level object properties. While ventral temporal and anterior insular cortices supported valence codes specific to vision and taste, both the medial and lateral orbitofrontal cortices (OFC), maintained a valence code independent of sensory origin. Further only the OFC code could classify experienced affect across participants. The entire valence spectrum is represented as a collective pattern in regional neural activity as sensory-specific and abstract codes, whereby the subjective quality of affect can be objectively quantified across stimuli, modalities, and people. PMID:24952643

  4. Discrimination of facial appearance stimuli in body dysmorphic disorder.

    PubMed

    Stangier, Ulrich; Adam-Schwebe, Stefanie; Müller, Thomas; Wolter, Manfred

    2008-05-01

    Cognitive-behavioral models of body dysmorphic disorder (BDD) propose that information-processing biases--in particular, selective attention to a defect in one's appearance as well as improved aesthetical perception--might contribute to the development or maintenance of the disorder. In the present study, the authors tested the hypothesis that patients with BDD discriminate facial appearance stimuli more accurately than controls. Sixty female patients from a dermatological clinic participated in the study: 21 patients with BDD, 19 patients with disfiguring dermatological conditions, and 20 patients with nondisfiguring dermatological disorders. Participants rated dissimilarities between pictures of neutral faces that had been manipulated with regard to aesthetic characteristics. Manipulation ratings of participants with BDD were significantly more accurate than those of both control groups. Implications of these results for cognitive theories of BDD are discussed.

  5. Stimuli Responsive Ionogels for Sensing Applications—An Overview

    PubMed Central

    Kavanagh, Andrew; Byrne, Robert; Diamond, Dermot; Fraser, Kevin J.

    2012-01-01

    This overview aims to summarize the existing potential of “Ionogels” as a platform to develop stimuli responsive materials. Ionogels are a class of materials that contain an Ionic Liquid (IL) confined within a polymer matrix. Recently defined as “a solid interconnected network spreading throughout a liquid phase”, the ionogel therefore combines the properties of both its solid and liquid components. ILs are low melting salts that exist as liquids composed entirely of cations and anions at or around 100 °C. Important physical properties of these liquids such as viscosity, density, melting point and conductivity can be altered to suit a purpose by choice of the cation/anion. Here we provide an overview to highlight the literature thus far, detailing the encapsulation of IL and responsive materials within these polymeric structures. Exciting applications in the areas of optical and electrochemical sensing, solid state electrolytes and actuating materials shall be discussed. PMID:24957961

  6. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    NASA Astrophysics Data System (ADS)

    Cussatlegras, A. S.; Le Gal, P.

    2005-02-01

    Bioluminescence of plankton organisms induced by water movements has long been observed and is still under investigations because of its great complexity. In particular, the exact mechanism occurring at the level of the cell has not been yet fully understood. This work is devoted to the study of the bioluminescence of the dinoflagellates plankton species Pyrocystis noctiluca in response to mechanical stimuli generated by water flows. Several experiments were performed with different types of flows in a Couette shearing apparatus. All of them converge to the conclusion that stationary homogeneous laminar shear does not trigger massive bioluminescence, but that acceleration and shear are both necessary to stimulate together an intense bioluminescence response. The distribution of the experimental bioluminescence thresholds is finally calculated from the light emission response for the Pyrocystis noctiluca species.

  7. Startle modulation before, during and after exposure to emotional stimuli.

    PubMed

    Dichter, Gabriel S; Tomarken, Andrew J; Baucom, Brian R

    2002-02-01

    Although affective modulation of the startle reflex is a highly replicable effect, the majority of studies have administered startle probes during exposure to affective stimuli. To examine more comprehensively the temporal course of startle potentiation, we assessed blink modulation before, during and immediately after exposure to positive, negative and neutral pictures. During each trial, cues about the affective content of pictures were presented, after which acoustic startle probes were delivered either before picture onset, during picture onset or immediately after picture offset. As expected, we observed a linear relation between picture valence and startle amplitude during picture viewing. Surprisingly, startle amplitude was larger while anticipating pleasant and unpleasant pictures relative to neutral pictures. No significant effects were observed during the offset phase. These results indicate that startle modulation is conditional upon temporal factors linked to stimulus onset and offset.

  8. Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems

    PubMed Central

    Marten, Gernot U; Gelbrich, Thorsten

    2010-01-01

    Summary A novel active biocatalytic reaction system is proposed by covalently immobilizing porcine pancreas trypsin within the thermoresponsive polymer shell of superparamagnetic Fe3O4 nanoparticles. Active ester-functional nanocarriers suitable for the immobilization of amino functional targets are obtained in a single polymerization step by grafting-from copolymerization of an active ester monomer from superparamagnetic cores. The comonomer, oligo(ethylene glycol) methyl ether methacrylate, has excellent water solubility at room temperature, biocompatibility, and a tunable lower critical solution temperature (LCST) in water. The phase separation can alternatively be initiated by magnetic heating caused by magnetic losses in ac magnetic fields. The immobilization of porcine pancreas trypsin to the core–shell nanoparticles results in highly active, nanoparticulate biocatalysts that can easily be separated magnetically. The enzymatic activity of the obtained biocatalyst system can be influenced by outer stimuli, such as temperature and external magnetic fields, by utilizing the LCST of the copolymer shell. PMID:20978622

  9. Coaxial nanotubes of stimuli responsive polymers with tunable release kinetics.

    PubMed

    Armagan, Efe; Ozaydin Ince, Gozde

    2015-11-01

    Stimuli responsive polymeric (SRP) nanotubes have great potential as nanocarriers of macromolecules due to their large surface areas and release mechanisms that can be activated externally. In this work, we demonstrate vapor phase synthesis of coaxial nanotubes with layers of different SRP polymers for improved release kinetics. Temperature responsive poly(N-isopropylacrylamide) (pNIPAAm), pH responsive poly(methacrylic acid) (pMAA) and poly(hydroxyethyl methacrylate) (pHEMA) are used to fabricate the responsive coaxial nanotubes and the phloroglucinol dye is used as the model molecule to study the release kinetics. Fastest release is observed with single layer pNIPAAm nanotubes with rates of 0.134 min(-1), whereas introducing pHEMA or pMAA as inner layers slows down the release, enabling tuning of the response. Furthermore, repeating the release studies multiple times shows that the release rates remain similar after each run, confirming the stability of the nanotubes. PMID:26333009

  10. Smart nanocontainers: progress on novel stimuli-responsive polymer vesicles.

    PubMed

    Feng, Anchao; Yuan, Jinying

    2014-04-01

    In the past decade, polymer vesicles prepared by self-assembly techniques have attracted increasing scientific interest based on their unique features highlighted with tunable membrane properties, versatility, stability, and capacity of transporting hydrophilic as well as hydrophobic species. Polymersomes exhibit intriguing potential applications such as cell mimicking dimensions and functions, tunable delivery vehicles, for the templating of biomineralization, nanoreactors, and as scaffolds for biological conjugation. In this Feature Article, an overview of the preparation and application of recently developed "smart" polymer vesicles, which can respond to the novel external stimuli, including carbon dioxide (CO2), electrochemical potential, ultrasound, enzyme, near-infrared light, and magnetic field is given. The response mechanism and morphology change are explored with specific focus on the functionalization of various domains of the polymer vesicles. In addition, the current limitations are explored as well as the challenges facing the development of these nanostructures toward real-world applications.

  11. Salivary response to olfactory food stimuli in anorexics and bulimics.

    PubMed

    LeGoff, D B; Leichner, P; Spigelman, M N

    1988-08-01

    Salivary response to olfactory food stimuli was assessed in controls and in anorexia nervosa and bulimia in-patients before and after two months of treatment. Before treatment, anorexics salivated less then controls while bulimics salivated more than controls. Following treatment, the salivary responses of eating-disordered subjects were much closer to controls. Salivary response to food was correlated with a measure of variability in caloric consumption. There may be two styles of dietary restraint: strict, unrelenting dieting, or the "dieting drone", exemplified by anorexic patients, and variable, "fence-sitting" dietary restraint, exemplified by bulimic patients. It is suggested that this two-style theory is able to account for past contradictory findings of heightened or suppressed saliva flow rates in dieters.

  12. Dopamine, paranormal belief, and the detection of meaningful stimuli.

    PubMed

    Krummenacher, Peter; Mohr, Christine; Haker, Helene; Brugger, Peter

    2010-08-01

    Dopamine (DA) is suggested to improve perceptual and cognitive decisions by increasing the signal-to-noise ratio. Somewhat paradoxically, a hyperdopaminergia (arguably more accentuated in the right hemisphere) has also been implied in the genesis of unusual experiences such as hallucinations and paranormal thought. To test these opposing assumptions, we used two lateralized decision tasks, one with lexical (tapping left-hemisphere functions), the other with facial stimuli (tapping right-hemisphere functions). Participants were 40 healthy right-handed men, of whom 20 reported unusual, "paranormal" experiences and beliefs ("believers"), whereas the remaining participants were unexperienced and critical ("skeptics"). In a between-subject design, levodopa (200 mg) or placebo administration was balanced between belief groups (double-blind procedure). For each task and visual field, we calculated sensitivity (d') and response tendency (criterion) derived from signal detection theory. Results showed the typical right visual field advantage for the lexical decision task and a higher d' for verbal than facial stimuli. For the skeptics, d' was lower in the levodopa than in the placebo group. Criterion analyses revealed that believers favored false alarms over misses, whereas skeptics displayed the opposite preference. Unexpectedly, under levodopa, these decision preferences were lower in both groups. We thus infer that levodopa (1) decreases sensitivity in perceptual-cognitive decisions, but only in skeptics, and (2) makes skeptics less and believers slightly more conservative. These results stand at odd to the common view that DA generally improves signal-to-noise ratios. Paranormal ideation seems an important personality dimension and should be assessed in investigations on the detection of signals in noise. PMID:19642883

  13. Coding of stimuli by ampullary afferents in Gnathonemus petersii.

    PubMed

    Engelmann, J; Gertz, S; Goulet, J; Schuh, A; von der Emde, G

    2010-10-01

    Weakly electric fish use electroreception for both active and passive electrolocation and for electrocommunication. While both active and passive electrolocation systems are prominent in weakly electric Mormyriform fishes, knowledge of their passive electrolocation ability is still scarce. To better estimate the contribution of passive electric sensing to the orientation toward electric stimuli in weakly electric fishes, we investigated frequency tuning applying classical input-output characterization and stimulus reconstruction methods to reveal the encoding capabilities of ampullary receptor afferents. Ampullary receptor afferents were most sensitive (threshold: 40 μV/cm) at low frequencies (<10 Hz) and appear to be tuned to a mix of amplitude and slope of the input signals. The low-frequency tuning was corroborated by behavioral experiments, but behavioral thresholds were one order of magnitude higher. The integration of simultaneously recorded afferents of similar frequency-tuning resulted in strongly enhanced signal-to-noise ratios and increased mutual information rates but did not increase the range of frequencies detectable by the system. Theoretically the neuronal integration of input from receptors experiencing opposite polarities of a stimulus (left and right side of the fish) was shown to enhance encoding of such stimuli, including an increase of bandwidth. Covariance and coherence analysis showed that spiking of ampullary afferents is sufficiently explained by the spike-triggered average, i.e., receptors respond to a single linear feature of the stimulus. Our data support the notion of a division of labor of the active and passive electrosensory systems in weakly electric fishes based on frequency tuning. Future experiments will address the role of central convergence of ampullary input that we expect to lead to higher sensitivity and encoding power of the system. PMID:20685928

  14. Separating in vivo mechanical stimuli for postpneumonectomy compensation: physiological assessment.

    PubMed

    Dane, D Merrill; Yilmaz, Cuneyt; Estrera, Aaron S; Hsia, Connie C W

    2013-01-01

    Following right pneumonectomy (PNX), the remaining lung expands and its perfusion doubles. Tissue and microvascular mechanical stresses are putative stimuli for initiating compensatory lung growth and remodeling, but their relative contributions to overall compensation remain uncertain. To temporally isolate the stimuli related to post-PNX lung expansion (parenchyma deformation) from those related to the sustained increase in perfusion (microvascular distention and shear), we replaced the right lung of adult dogs with a custom-shaped inflated prosthesis. Following stabilization of perfusion and wound healing 4 mo later, the prosthesis was either acutely deflated (DEF group) or kept inflated (INF group). Physiological studies were performed pre-PNX, 4 mo post-PNX (inflated prosthesis, INF1), and again 4 mo postdeflation (DEF) compared with controls with simultaneous INF prosthesis (INF2). Perfusion to the remaining lung increased ~76-113% post-PNX (INF1 and INF2) and did not change postdeflation. Post-PNX (INF prosthesis) end-expiratory lung volume (EELV) and lung and membrane diffusing capacities (DL(CO) and DM(CO)) at a given perfusion were 25-40% below pre-PNX baseline. In the INF group EELV, DL(CO) and DM(CO) remained stable or declined slightly with time. In contrast, all of these parameters increased significantly after deflation and were 157%, 26%, and 47%, respectively, above the corresponding control values (INF2). Following delayed deflation, lung expansion accounted for 44%-48% of total post-PNX compensatory increase in exercise DL(CO) and peak O(2) uptake; the remainder fraction is likely attributable to the increase in perfusion. Results suggest that expansion-related parenchyma mechanical stress and perfusion-related microvascular stress contribute in equal proportions to post-PNX alveolar growth and remodeling.

  15. Perfusion-related stimuli for compensatory lung growth following pneumonectomy.

    PubMed

    Dane, D Merrill; Yilmaz, Cuneyt; Gyawali, Dipendra; Iyer, Roshni; Ravikumar, Priya; Estrera, Aaron S; Hsia, Connie C W

    2016-07-01

    Following pneumonectomy (PNX), two separate mechanical forces act on the remaining lung: parenchymal stress caused by lung expansion, and microvascular distension and shear caused by increased perfusion. We previously showed that parenchymal stress and strain explain approximately one-half of overall compensation; the remainder was presumptively attributed to perfusion-related factors. In this study, we directly tested the hypothesis that perturbation of regional pulmonary perfusion modulates post-PNX lung growth. Adult canines underwent banding of the pulmonary artery (PAB) to the left caudal (LCa) lobe, which caused a reduction in basal perfusion to LCa lobe without preventing the subsequent increase in its perfusion following right PNX while simultaneously exaggerating the post-PNX increase in perfusion to the unbanded lobes, thereby creating differential perfusion changes between banded and unbanded lobes. Control animals underwent sham pulmonary artery banding followed by right PNX. Pulmonary function, regional pulmonary perfusion, and high-resolution computed tomography of the chest were analyzed pre-PNX and 3-mo post-PNX. Terminally, the remaining lobes were fixed for detailed morphometric analysis. Results were compared with corresponding lobes in two control (Sham banding and normal unoperated) groups. PAB impaired the indices of post-PNX extravascular alveolar tissue growth by up to 50% in all remaining lobes. PAB enhanced the expected post-PNX increase in alveolar capillary formation, measured by the prevalence of double-capillary profiles, in both unbanded and banded lobes. We conclude that perfusion distribution provides major stimuli for post-PNX compensatory lung growth independent of the stimuli provided by lung expansion and parenchymal stress and strain.

  16. Adaptive liquid microlenses activated by stimuli-responsive hydrogels

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Agarwal, Abhishek K.; Beebe, David J.; Jiang, Hongrui

    2006-08-01

    Despite its compactness, the human eye can easily focus on different distances by adjusting the shape of its lens with the help of ciliary muscles. In contrast, traditional man-made optical systems achieve focusing by physical displacement of the lenses used. But in recent years, advances in miniaturization technology have led to optical systems that no longer require complicated mechanical systems to tune and adjust optical performance. These systems have found wide use in photonics, displays and biomedical systems. They are either based on arrays of microlenses with fixed focal lengths, or use external control to adjust the microlens focal length. An intriguing example is the tunable liquid lens, where electrowetting or external pressure manipulates the shape of a liquid droplet and thereby adjusts its optical properties. Here we demonstrate a liquid lens system that allows for autonomous focusing. The central component is a stimuli-responsive hydrogel integrated into a microfluidic system and serving as the container for a liquid droplet, with the hydrogel simultaneously sensing the presence of stimuli and actuating adjustments to the shape-and hence focal length-of the droplet. By working at the micrometre scale where ionic diffusion and surface tension scale favourably, we can use pinned liquid-liquid interfaces to obtain stable devices and realize response times of ten to a few tens of seconds. The microlenses, which can have a focal length ranging from -∞ to +∞ (divergent and convergent), are also readily integrated into arrays that may find use in applications such as sensing, medical diagnostics and lab-on-a-chip technologies.

  17. Visual laterality in dolphins: importance of the familiarity of stimuli

    PubMed Central

    2012-01-01

    Background Many studies of cerebral asymmetries in different species lead, on the one hand, to a better understanding of the functions of each cerebral hemisphere and, on the other hand, to develop an evolutionary history of hemispheric laterality. Our animal model is particularly interesting because of its original evolutionary path, i.e. return to aquatic life after a terrestrial phase. The rare reports concerning visual laterality of marine mammals investigated mainly discrimination processes. As dolphins are migrant species they are confronted to a changing environment. Being able to categorize new versus familiar objects would allow dolphins a rapid adaptation to novel environments. Visual laterality could be a prerequisite to this adaptability. To date, no study, to our knowledge, has analyzed the environmental factors that could influence their visual laterality. Results We investigated visual laterality expressed spontaneously at the water surface by a group of five common bottlenose dolphins (Tursiops truncatus) in response to various stimuli. The stimuli presented ranged from very familiar objects (known and manipulated previously) to familiar objects (known but never manipulated) to unfamiliar objects (unknown, never seen previously). At the group level, dolphins used their left eye to observe very familiar objects and their right eye to observe unfamiliar objects. However, eyes are used indifferently to observe familiar objects with intermediate valence. Conclusion Our results suggest different visual cerebral processes based either on the global shape of well-known objects or on local details of unknown objects. Moreover, the manipulation of an object appears necessary for these dolphins to construct a global representation of an object enabling its immediate categorization for subsequent use. Our experimental results pointed out some cognitive capacities of dolphins which might be crucial for their wild life given their fission-fusion social system

  18. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    PubMed

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

  19. Perceived duration of Visual and Tactile Stimuli Depends on Perceived Speed

    PubMed Central

    Tomassini, Alice; Gori, Monica; Burr, David; Sandini, Giulio; Morrone, Maria Concetta

    2011-01-01

    It is known that the perceived duration of visual stimuli is strongly influenced by speed: faster moving stimuli appear to last longer. To test whether this is a general property of sensory systems we asked participants to reproduce the duration of visual and tactile gratings, and visuo-tactile gratings moving at a variable speed (3.5–15 cm/s) for three different durations (400, 600, and 800 ms). For both modalities, the apparent duration of the stimulus increased strongly with stimulus speed, more so for tactile than for visual stimuli. In addition, visual stimuli were perceived to last approximately 200 ms longer than tactile stimuli. The apparent duration of visuo-tactile stimuli lay between the unimodal estimates, as the Bayesian account predicts, but the bimodal precision of the reproduction did not show the theoretical improvement. A cross-modal speed-matching task revealed that visual stimuli were perceived to move faster than tactile stimuli. To test whether the large difference in the perceived duration of visual and tactile stimuli resulted from the difference in their perceived speed, we repeated the time reproduction task with visual and tactile stimuli matched in apparent speed. This reduced, but did not completely eliminate the difference in apparent duration. These results show that for both vision and touch, perceived duration depends on speed, pointing to common strategies of time perception. PMID:21941471

  20. Avoidance of affective pain stimuli predicts chronicity in patients with acute low back pain.

    PubMed

    Sharpe, Louise; Haggman, Sonia; Nicholas, Michael; Dear, Blake F; Refshauge, Kathryn

    2014-01-01

    This prospective study of acute and sub-acute low back pain (LBP) patients was conducted to assess whether attentional biases predicted chronic pain status 3 and 6 months later. The attentional biases of 100 LBP patients were assessed within 3 months of developing pain and 6 months later. Participants also completed measures associated with outcome at 3 assessment points: baseline, 3 and 6 months later. Current pain status was assessed at follow-ups. Patients were classified as those that met standard criteria for chronic pain or those who did not (i.e., the comparison group). At baseline, participants demonstrated a bias toward sensory pain words. However, biases toward sensory pain words did not differentiate those who subsequently developed chronic pain and those who did not at either follow-up. The same bias was observed 6 months later, but again it failed to distinguish between the chronic pain and comparison groups. However, subjects who developed chronic pain at both 3 (n=22) and 6 (n=21) months demonstrated biases away from affective pain words at baseline but not 6 months later, in comparison to other participants. These results remained significant in multivariate analyses. These findings are consistent with patterns observed in the previous research, and suggest that avoidance of emotionally laden pain-related stimuli (i.e., affective pain words) is associated with negative outcomes for LBP patients in the acute and sub-acute phase. This research suggests that attentional biases in relation to pain-related stimuli are important for the development of chronic pain, but are more complex than initially thought. PMID:24028848

  1. Burst-Modulated Waveforms Optimize Electrical Stimuli for Charge Efficiency and Fiber Selectivity.

    PubMed

    Qing, Kurt Y; Ward, Matthew P; Irazoqui, Pedro P

    2015-11-01

    We demonstrate an alternative method of designing electrical stimuli-termed burst modulation--for producing different patterns of nerve fiber recruitment. By delivering electrical charge in bursts of "pulsons"--miniature pulses-instead of as long continuous pulses, our method can optimize the waveform for stimulation efficiency and fiber selectivity. In our in vivo validation experiments, while maintaining C fibers of the rat vagus nerve at ∼ 50% activation with different waveforms, the burst-modulated waveform produced 11% less A fiber activation than the standard rectangular pulse waveform (rectangular: 50.8±1.5% of maximal A response, mean ± standard error of the mean; burst-modulated: 39.8 ±1.3%), which equates to a 20% reduction in A fiber response magnitude. In addition, the burst-modulated waveform required 45% less stimulus charge per phase to maintain 50% C fiber activation (rectangular: 20.7 ±0.86 μC; burst-modulated: 11.3 ±0.41 μC ). Burst-modulated waveforms produced consistent patterns of fiber recruitment within and across animals, which indicate that our methods of stimulus design and response analysis provide a reliable way to study neurostimulation and deliver therapy.

  2. Dot comparison stimuli are not all alike: the effect of different visual controls on ANS measurement.

    PubMed

    Clayton, Sarah; Gilmore, Camilla; Inglis, Matthew

    2015-10-01

    The most common method of indexing Approximate Number System (ANS) acuity is to use a nonsymbolic dot comparison task. Currently there is no standard protocol for creating the dot array stimuli and it is unclear whether tasks that control for different visual cues, such as cumulative surface area and convex hull size, measure the same cognitive constructs. Here we investigated how the accuracy and reliability of magnitude judgements is influenced by visual controls through a comparison of performance on dot comparison trials created with two standard methods: the Panamath program and Gebuis & Reynvoet's script. Fifty-one adult participants completed blocks of trials employing images constructed using the two protocols twice to obtain a measure of immediate test-retest reliability. We found no significant correlation between participants' accuracy scores on trials created with the two protocols, suggesting that tasks employing these protocols may measure different cognitive constructs. Additionally, there were significant differences in the test-retest reliabilities for trials created with each protocol. Finally, strong congruency effects for convex hull size were found for both sets of protocol trials, which provides some clarification for conflicting results in the literature.

  3. Stimuli-Responsive Metal Organic Frameworks: Stimuli-Responsive Metal Organic Frameworks for Energy-Efficient Post Combustion Capture

    SciTech Connect

    2010-07-01

    IMPACCT Project: A team led by three professors at Texas A&M is developing a subset of metal organic frameworks that respond to stimuli such as small changes in temperature to trap CO2 and then release it for storage. These frameworks are a promising class of materials for carbon capture applications because their structure and chemistry can be controlled with great precision. Because the changes in temperature required to trap and release CO2 in Texas A&M’s frameworks are much smaller than in other carbon capture approaches, the amount of energy or stimulus that has to be diverted from coal-fired power plants to accomplish this is greatly reduced. The team is working to alter the materials so they bind only with CO2, and are stable enough to withstand the high temperatures found in the chimneys of coal-fired power plants.

  4. The Spatial Standard Observer

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Ahumada, Albert J, Jr.

    2006-01-01

    The spatial standard observer is a computational model that provides a measure of the visibility of a target in a uniform background image or of the visual discriminability of two images. Standard observers have long been used in science and industry to quantify the discriminability of colors. Color standard observers address the spectral characteristics of visual stimuli, while the spatial standard observer (SSO), as its name indicates, addresses spatial characteristics. The SSO is based on a model of human vision. The SSO was developed in a process that included evaluation of a number of earlier mathematical models that address optical, physiological, and psychophysical aspects of spatial characteristics of human visual perception. Elements of the prior models are incorporated into the SSO, which is formulated as a compromise between accuracy and simplicity. The SSO operates on a digitized monochrome still image or on a pair of such images. The SSO consists of three submodels that operate sequentially on the input image(s): 1. A contrast model, which converts an input monochrome image to a luminance contrast image, wherein luminance values are expressed as excursions from, and normalized to, a mean; 2. A contrast-sensitivity-filter model that includes an oblique-effect filter (which accounts for the decline in contrast sensitivity at oblique viewing angles); and 3. A spatial summation model, in which responses are spatially pooled by raising each pixel to the power beta, adding the results, and raising the sum to the 1/b power. In this model, b=2.9 was found to be a suitable value. The net effect of the SSO is to compute a numerical measure of the perceptual strength of the single image, or of the visible difference (denoted the perceptual distance) between two images. The unit of a measure used in the SSO is the just noticeable difference (JND), which is a standard measure of perceptual discriminability. A target that is just visible has a measure of 1 JND.

  5. Infrastructure Standardization.

    ERIC Educational Resources Information Center

    Yow, Donna

    2002-01-01

    Describes the development of technological design standards for a 35-school construction/renovation effort by Guilford County Schools in North Carolina. The standards encompassed the physical infrastructure, telephone systems, and paging systems. (EV)

  6. P1 and N170 components distinguish human-like and animal-like makeup stimuli.

    PubMed

    Luo, Shuwei; Luo, Wenbo; He, Weiqi; Chen, Xu; Luo, Yuejia

    2013-06-19

    This study used event-related potentials to investigate the sensitivity of P1 and N170 components to human-like and animal-like makeup stimuli, which were derived from pictures of Peking opera characters. As predicted, human-like makeup stimuli elicited larger P1 and N170 amplitudes than did animal-like makeup stimuli. Interestingly, a right hemisphere advantage was observed for human-like but not for animal-like makeup stimuli. Dipole source analyses of 130-200-ms window showed that the bilateral fusiform face area may contribute to the differential sensitivity of the N170 component in response to human-like and animal-like makeup stimuli. The present study suggests that the amplitudes of both the P1 and the N170 are sensitive for the mouth component of face-like stimuli.

  7. Performance Standards.

    ERIC Educational Resources Information Center

    Conley, David T.

    1997-01-01

    Standards-based systems generally require students to meet the performance level specified in order to proceed or be certified. This issue of the Oregon School Study Council (OSSC) Bulletin surveys the types of standards currently being proposed. After an introductory chapter, chapter 2 describes eight components of standards, illustrated with a…

  8. Evidence of Nb-Ta mobility in high temperature F-rich fluids evidenced by the La Bosse quartz-Nb-ferberite stockwork (Echassières, French Massif Central).

    NASA Astrophysics Data System (ADS)

    Marignac, C.; Cuney, M.

    2012-04-01

    In the Echassières district (northern French Massif Central), the 310 Ma Beauvoir granite (a P-rich peraluminous RMG) overprints a quartz-ferberite stockwork. The 900 m-deep GPF1 scientific hole shows that the stockwork is split into two parts by the gently dipping Beauvoir intrusion: the upper section (~ 100m thick) occurs in the La Bosse quarry, , and the lower section (≥ 60 m thick) below the granite floor. The root of the stockwork (hypothetic La Bosse granite) has not been reached. The stockwork comprises flat-lying quartz veins (≤ 0.6 m thick) concordant to the regional schistosity of surrounding micaschists, and steep N10-N50°E quartz veins (≤ 0.2 m thick). The two sets result from hydraulic fracturing, and consistently display crack seal features. A family of aplites and aplo-pegmatites dikes follow the same set of fractures, being either later (with partial dissolution of pre-existing quartz veins) or earlier, than the quartz veins. There is no alteration, nor associated mineral other than ferberite, at the La Bosse quarry, whereas micaceous selvages are observed in the lower section. Ferberite display a trend of ferberite enrichment with increasing depth (0.71 to 0.95 Fb mole%). In the La Bosse quarry, three ferberite habitus are present: acicular, lanceolate and prismatic. Acicular crystals are typically nicely zoned, with alternating Nb-rich (4.95±0.94 % Nb2O5) and Nb-poor (1.57±0.38 % Nb2O5) growth bands. Ta (up to 0.30 Ta2O5), Ti and Sn are also enriched in the Nb-rich bands. Nb and Ta incorporation into the ferberite is in the form of columbite, as either true solid solution or nanoinclusions. Lanceolate crystals have a similarly zoned acicular core and a Nb-poor rim (1.08±0.66 % Nb2O5). Prismatic crystals are unzoned and Nb-poor (0.67±0.20 % Nb2O5). In the lower part of the stockwork, the Nb contents are lower (2.17 % Nb2O5 in the Nb-rich bands, 1.36 % in the Nb-poor bands, 0.08 % in the unzoned cortex, 0.15 % in the unzoned prisms

  9. Evidence of Nb-Ta mobility in high temperature F-rich fluids evidenced by the La Bosse quartz-Nb-ferberite stockwork (Echassières, French Massif Central).

    NASA Astrophysics Data System (ADS)

    Marignac, C.; Cuney, M.

    2012-04-01

    In the Echassières district (northern French Massif Central), the 310 Ma Beauvoir granite (a P-rich peraluminous RMG) overprints a quartz-ferberite stockwork. The 900 m-deep GPF1 scientific hole shows that the stockwork is split into two parts by the gently dipping Beauvoir intrusion: the upper section (~ 100m thick) occurs in the La Bosse quarry, , and the lower section (≥ 60 m thick) below the granite floor. The root of the stockwork (hypothetic La Bosse granite) has not been reached. The stockwork comprises flat-lying quartz veins (≤ 0.6 m thick) concordant to the regional schistosity of surrounding micaschists, and steep N10-N50°E quartz veins (≤ 0.2 m thick). The two sets result from hydraulic fracturing, and consistently display crack seal features. A family of aplites and aplo-pegmatites dikes follow the same set of fractures, being either later (with partial dissolution of pre-existing quartz veins) or earlier, than the quartz veins. There is no alteration, nor associated mineral other than ferberite, at the La Bosse quarry, whereas micaceous selvages are observed in the lower section. Ferberite display a trend of ferberite enrichment with increasing depth (0.71 to 0.95 Fb mole%). In the La Bosse quarry, three ferberite habitus are present: acicular, lanceolate and prismatic. Acicular crystals are typically nicely zoned, with alternating Nb-rich (4.95±0.94 % Nb2O5) and Nb-poor (1.57±0.38 % Nb2O5) growth bands. Ta (up to 0.30 Ta2O5), Ti and Sn are also enriched in the Nb-rich bands. Nb and Ta incorporation into the ferberite is in the form of columbite, as either true solid solution or nanoinclusions. Lanceolate crystals have a similarly zoned acicular core and a Nb-poor rim (1.08±0.66 % Nb2O5). Prismatic crystals are unzoned and Nb-poor (0.67±0.20 % Nb2O5). In the lower part of the stockwork, the Nb contents are lower (2.17 % Nb2O5 in the Nb-rich bands, 1.36 % in the Nb-poor bands, 0.08 % in the unzoned cortex, 0.15 % in the unzoned prisms

  10. Timing and classifying brief acoustic stimuli by songbirds and humans.

    PubMed

    Weisman, R; Brownlie, L; Olthof, A; Njegovan, M; Sturdy, C; Mewhort, D

    1999-04-01

    The durations of animals' brief vocalizations provide conspecifics with important recognition cues. In the present experiments, zebra finches and humans (trained musicians) were rewarded for responding after S+ (standard) auditory signals from 56 to 663 ms and not for responding after shorter or longer S- (comparison) durations from 10 to 3684 ms. With either a single standard (Experiment 1) or multiple standards (Experiment 2), both zebra finches and humans timed brief signals to about the same level of accuracy. The results were in qualitative agreement with predictions from scalar timing theory and its connectionist implementation in both experiments. The connectionist model provides a good quantitative account of temporal gradients with a single standard (Experiment 1) but not with multiple standards (Experiment 2). PMID:10331915

  11. Nociceptive stimuli induce changes in somatosensory responses of rat dorsal column nuclei neurons.

    PubMed

    Costa-García, Miguel; Nuñez, Angel

    2004-10-29

    Accumulating evidence suggest that the dorsal column nuclei (DCN) neurons play a role in nociception. To evaluate DCN neuronal responses to nociceptive stimuli, unit recordings were performed in urethane-anesthesized rats. Neurons selected for this analysis displayed a low spontaneous firing rate and some of them were antidromically activated by electrical stimulation of the ventral posterolateral thalamic nucleus. Formalin injections into receptive fields (RFs) of DCN cells, or applications of short-lasting and long-lasting thermal nociceptive stimuli were used. DCN neurons displayed smaller responses when long-lasting nociceptive thermal stimuli were applied to their RFs in comparison with values obtained from the innocuous cutaneous stimulation (5.2+/-1.0 and 4.0+/-0.6 spikes/stimuli, respectively; p=0.02). Formalin also decreased the responses to innocuous cutaneous stimuli when these stimuli were applied to the formalin injection site (2.6+/-0.3 spikes/stimuli in control conditions and 1.8+/-0.3 spikes/stimuli 20 min after formalin; p=0.002). In contrast, responses to sensory stimuli applied at the periphery of the RF after formalin injection increased (2.2+/-0.2 to 2.8+/-0.3 spikes/stimuli; p=0.005). In some cases, DCN neurons expanded their RF. Fiber input to the DCN did not modify their somatosensory responses when nociceptive stimuli were applied. Results demonstrate that thermal and formalin nociceptive stimuli modify the somatosensory responses of DCN neurons. Thus, decreasing somatosensory responses at the pain induction site or the generation of allodynia may be due to the activity of DCN neurons.

  12. Effects of instruction on acquisition and extinction of electrodermal responses to fear-relevant stimuli.

    PubMed

    Hugdahl, K; Ohman, A

    1977-09-01

    In the present study we examined the hypothesis that electrodermal responses conditioned to fear-relevant stimuli are insensitive to verbal instructions. In the first experiment, different groups of subjects were conditioned to fear-relevant and fear-irrelevant control stimuli in a long interstimulus interval differential paradigm with shock as the unconditioned stimulus. Then half of the subjects were informed that no more shocks would be presented, and a number of extinction trials followed. The instruction completely abolished responding to fear-irrelevant stimuli, while leaving responses to the fear-relevant stimuli unaffected. In the second experiment, subjects were "conditioned" to fear-relevant or irrelevant stimuli by an instruction involving threat of shock. This manipulation potentiated potentiated responses to fear-relevant stimuli significantly more than responses to fear-irrelevant stimuli. Thus, instruction had a symmetrical effect on acquisition and extinction to fear-irrelevant stimuli, whereas it facilitated acquisition but was ineffective in reducing responding to the other class of stimuli. These results are related to a preparedness theory, and their relevance for an understanding of phobias is discussed.

  13. Interpretative bias in spider phobia: Perception and information processing of ambiguous schematic stimuli.

    PubMed

    Haberkamp, Anke; Schmidt, Filipp

    2015-09-01

    This study investigates the interpretative bias in spider phobia with respect to rapid visuomotor processing. We compared perception, evaluation, and visuomotor processing of ambiguous schematic stimuli between spider-fearful and control participants. Stimuli were produced by gradually morphing schematic flowers into spiders. Participants rated these stimuli related to their perceptual appearance and to their feelings of valence, disgust, and arousal. Also, they responded to the same stimuli within a response priming paradigm that measures rapid motor activation. Spider-fearful individuals showed an interpretative bias (i.e., ambiguous stimuli were perceived as more similar to spiders) and rated spider-like stimuli as more unpleasant, disgusting, and arousing. However, we observed no differences between spider-fearful and control participants in priming effects for ambiguous stimuli. For non-ambiguous stimuli, we observed a similar enhancement for phobic pictures as has been reported previously for natural images. We discuss our findings with respect to the visual representation of morphed stimuli and to perceptual learning processes.

  14. Alleged Approach-Avoidance Conflict for Food Stimuli in Binge Eating Disorder

    PubMed Central

    Leehr, Elisabeth J.; Schag, Kathrin; Brinkmann, Amelie; Ehlis, Ann-Christine; Fallgatter, Andreas J.; Zipfel, Stephan; Giel, Katrin E.; Dresler, Thomas

    2016-01-01

    Objective Food stimuli are omnipresent and naturally primary reinforcing stimuli. One explanation for the intake of high amounts of food in binge eating disorder (BED) is a deviant valuation process. Valuation of food stimuli is supposed to influence approach or avoidance behaviour towards food. Focusing on self-reported and indirect (facial electromyography) valuation process, motivational aspects in the processing of food stimuli were investigated. Methods We compared an overweight sample with BED (BED+) with an overweight sample without BED (BED-) and with normal weight controls (NWC) regarding their self-reported and indirect (via facial electromyography) valuation of food versus non-food stimuli. Results Regarding the self-reported valuation, the BED+ sample showed a significantly stronger food-bias compared to the BED- sample, as food stimuli were rated as significantly more positive than the non-food stimuli in the BED+ sample. This self-reported valuation pattern could not be displayed in the indirect valuation. Food stimuli evoked negative indirect valuation in all groups. The BED+ sample showed the plainest approach-avoidance conflict marked by a diverging self-reported (positive) and indirect (negative) valuation of food stimuli. Conclusions BED+ showed a deviant self-reported valuation of food as compared to BED-. The valuation process of the BED+ sample seems to be characterized by a motivational ambivalence. This ambivalence should be subject of further studies and may be of potential use for therapeutic interventions. PMID:27045169

  15. Detection of low salience whisker stimuli requires synergy of tectal and thalamic sensory relays

    PubMed Central

    Cohen, Jeremy D.; Castro-Alamancos, Manuel A.

    2010-01-01

    Detection of a sensory stimulus depends on its psychophysical saliency; the higher the saliency, the easier the detection. But it is not known if sensory relay nuclei differ in their ability to detect low salient whisker stimuli. We found that reversible lesions of either the somatosensory thalamus or superior colliculus blocked detection of a low salience whisker conditioned stimulus (WCS) in an active avoidance task, without affecting detection of a high salience WCS. Thus, thalamic and tectal sensory relays work synergistically to detect low salient stimuli during avoidance behavior, but are redundant during detection of highly salient stimuli. We also recorded electrophysiological responses evoked by high and low salience stimuli in the superior colliculus and barrel cortex of freely behaving animals during active exploration, awake immobility and sensory detection in the active avoidance task. Field potential (FP) responses evoked in barrel cortex and superior colliculus by high intensity stimuli are larger and adapt more to frequency than those evoked by low intensity stimuli. FP responses are also more suppressed and adapt less during active exploration, and become further suppressed in barrel cortex during successful detection of either high or low salient stimuli in the active avoidance task. In addition, unit recordings revealed that firing rate increases in superior colliculus during active exploration, and especially during successful detection of either high or low salient stimuli in the active avoidance task. We conclude that detection of low salient stimuli is achieved by a sparse neural code distributed through multiple sensory relays. PMID:20147551

  16. Alleged Approach-Avoidance Conflict for Food Stimuli in Binge Eating Disorder

    PubMed Central

    Leehr, Elisabeth J.; Schag, Kathrin; Brinkmann, Amelie; Ehlis, Ann-Christine; Fallgatter, Andreas J.; Zipfel, Stephan; Giel, Katrin E.; Dresler, Thomas

    2016-01-01

    Objective Food stimuli are omnipresent and naturally primary reinforcing stimuli. One explanation for the intake of high amounts of food in binge eating disorder (BED) is a deviant valuation process. Valuation of food stimuli is supposed to influence approach or avoidance behaviour towards food. Focusing on self-reported and indirect (facial electromyography) valuation process, motivational aspects in the processing of food stimuli were investigated. Methods We compared an overweight sample with BED (BED+) with an overweight sample without BED (BED-) and with normal weight controls (NWC) regarding their self-reported and indirect (via facial electromyography) valuation of food versus non-food stimuli. Results Regarding the self-reported valuation, the BED+ sample showed a significantly stronger food-bias compared to the BED- sample, as food stimuli were rated as significantly more positive than the non-food stimuli in the BED+ sample. This self-reported valuation pattern could not be displayed in the indirect valuation. Food stimuli evoked negative indirect valuation in all groups. The BED+ sample showed the plainest approach-avoidance conflict marked by a diverging self-reported (positive) and indirect (negative) valuation of food stimuli. Conclusions BED+ showed a deviant self-reported valuation of food as compared to BED-. The valuation process of the BED+ sample seems to be characterized by a motivational ambivalence. This ambivalence should be subject of further studies and may be of potential use for therapeutic interventions. PMID:27045169

  17. Optical delivery of liposome encapsulated chemical stimuli to neuronal cells

    NASA Astrophysics Data System (ADS)

    Pinato, Giulietta; Raffaelli, Tiziano; D'Este, Elisa; Tavano, Federica; Cojoc, Dan

    2011-09-01

    Spatially confined and precise time delivery of neuroactive molecules is an important issue in neurophysiology. In this work we developed a technique for delivering chemical stimuli to cultured neurons consisting in encapsulating the molecules of interest in liposomes. These vectors were then loaded in reservoirs consisting of glass capillaries. The reservoirs were placed in the recording chamber and single liposomes were trapped and transported out by optical tweezers to the site of stimulation on cultured neurons. Finally, the release of liposome content was induced by application of UV-pulses, breaking the liposome membrane. The efficiency of encapsulation and release were first evaluated by loading the liposomes with fluorescein. In order to test the effect of the UV-induced release, liposomes with diameter ranging from 1 to 10 μm (fL to pL volumes), were filled with KCl and tested on neuronal cells. Neuronal cultures, loaded with Ca2+ dye, were monitored by imaging intracellular Ca2+. An efficient release from the liposomes was demonstrated by detectable calcium signals, indicating stimulated depolarization of the neuronal cells by KCl. The present technique represents an alternative method for focal chemical stimulation of cultured cells that circumvents some of the limitations of microejection and photorelease of caged compounds.

  18. Perception of facial attractiveness from static and dynamic stimuli.

    PubMed

    Kościński, Krzysztof

    2013-01-01

    Although people we meet in real life are usually seen in motion, research on facial attractiveness has predominantly been conducted on static facial images. This raises a question about ecological validity of results obtained in such studies. Recently, several studies endeavoured to determine the concordance between attractiveness of faces seen on photos and video clips, but their results are markedly divergent, frequently indicating no concordance. In the present study, the association between attractiveness of facial images and clips was tested on a larger sample than has previously been reported (106 females, 102 males), and features under the face owner's control (scalp and facial hair, makeup, mouth expression) were controlled for. Two types of facial images were used: photographs and frames extracted from films. Correlation coefficients between attractiveness of static and dynamic faces were high (about 0.7), did not depend on facial sex or image type (photograph/frame), and did not diminish when the covariates were controlled for. Furthermore, the importance of facial averageness, femininity/ masculinity, symmetry, fattiness, skin health, and mouth expression for attractiveness proved similar for static and dynamic stimuli. This leads to the optimistic conclusion that results of studies relying on attractiveness assessments of static facial images are ecologically valid.

  19. Recency and suffix effects with immediate recall of olfactory stimuli.

    PubMed

    Miles, C; Jenkins, R

    2000-05-01

    In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.

  20. Hangover hyperthermia in rats: relation to tolerance and external stimuli.

    PubMed

    Sinclair, J D; Taira, T

    1988-01-01

    The recent finding of rebound hyperthermia in rats on the day after a single IP injection or oral intubation of ethanol was confirmed. In our studies, body temperature measured by rectal probe was significantly decreased for 8 h after 2.5 g/kg ethanol IP and was then significantly elevated 16-24 h after injection; increased vocalization during handling at 24 h was also found. However, rats isolated in a sound-attenuation chamber with remote temperature measurement showed no hyperthermia even though they were hypothermic during intoxication. The results do not support the hypothesis that rebound hyperthermia was caused by either a disruption of circadian rhythms, or by a mild abstinence syndrome alone. Instead, it appears that external stimuli, perhaps related to stress or associated with ethanol administration, are necessary on the day after a moderate dose of ethanol to produce the hyperthermia. Like hangover in humans, hyperthermia was reduced in rats made tolerant to ethanol: both the hypothermia and the rebound hyperthermia were significantly lower on the day after the 12th alternate-day ethanol injection than after the first injection. The aftereffects in rats of acute intoxication are, by definition, hangover signs, and they resemble hangover in humans in several ways, but their relevance as an animal model of hangover remains to be determined.

  1. Tactile Stimuli Increase Effects of Modality Compatibility in Task Switching.

    PubMed

    Stephan, Denise Nadine; Koch, Iring

    2015-01-01

    Modality compatibility refers to the similarity of stimulus modality and modality of response-related sensory consequences. Previous dual-task studies found increased switch costs for modality incompatible tasks (auditory-manual/visual-vocal) compared to modality compatible tasks (auditory-vocal/visual-manual). The present task-switching study further examined modality compatibility and investigated vibrotactile stimulation as a novel alternative to visual stimulation. Interestingly, a stronger modality compatibility effect on switch costs was revealed for the group with tactile-auditory stimulation compared to the visual-auditory stimulation group. We suggest that the modality compatibility effect is based on crosstalk of central processing codes due to ideomotor "backward" linkages between the anticipated response effects and the stimuli indicating this response. This crosstalk is increased in the tactile-auditory stimulus group compared to the visual-auditory stimulus group due to a higher degree of ideomotor-compatibility in the tactile-manual tasks. Since crosstalk arises between tasks, performance is only affected in task switching and not in single tasks.

  2. Investigating Mixture Interactions of Astringent Stimuli Using the Isobole Approach.

    PubMed

    Fleming, Erin E; Ziegler, Gregory R; Hayes, John E

    2016-09-01

    Astringents (alum, malic acid, tannic acid) representing 3 broad classes (multivalent salts, organic acids, and polyphenols) were characterized alone, and as 2- and 3-component mixtures using isoboles. In experiment 1, participants rated 7 attributes ("astringency," the sub-qualities "drying," "roughing," and "puckering," and the side tastes "bitterness," "sourness," and "sweetness") using direct scaling. Quality specific power functions were calculated for each stimulus. In experiment 2, the same participants characterized 2- and 3-component mixtures. Multiple factor analysis (MFA) and hierarchical clustering on attribute ratings across stimuli indicate "astringency" is highly related to "bitterness" as well as "puckering," and the subqualities "drying" and "roughing" are somewhat redundant. Moreover, power functions were used to calculate indices of interaction (I) for each attribute/mixture combination. For "astringency," there was evidence of antagonism, regardless of the type of mixture. Conversely, for subqualities, the pattern of interaction depended on the mixture type. Alum/tannic acid and tannic acid/malic acid mixtures showed evidence of synergy for "drying" and "roughing"; alum/malic acid mixtures showed evidence of antagonism for "drying," "roughing," and "puckering." Collectively, these data clarify some semantic ambiguity regarding astringency and its subqualities, as well as the nature of interactions of among different types of astringents. Present data are not inconsistent with the idea that astringency arises from multiple mechanisms, although it remains to be determined whether the synergy observed here might reflect simultaneous activation of these multiple mechanisms. PMID:27252355

  3. Capture of attention to threatening stimuli without perceptual awareness

    PubMed Central

    Lin, Jeffrey Y.; Murray, Scott O.; Boynton, Geoffrey M.

    2009-01-01

    Summary Visual images that convey threatening information can automatically capture attention [1-4]. One example is an object looming in the direction of the observer—presumably because such a stimulus signals an impending collision [5]. A critical question for understanding the relationship between attention and conscious awareness is whether awareness is required for this type of prioritized attentional selection [6]. Although it has been suggested that visual spatial attention can only be affected by consciously perceived events [7], we show that automatic allocation of attention can occur even without conscious awareness of impending threat. We used a visual search task to show that a looming stimulus on a collision path with an observer captures attention but a looming stimulus on a near-miss path does not. Critically, observers were unaware of any difference between collision and near-miss stimuli even when explicitly asked to discriminate between them in separate experiments. These results counter traditional salience-based models of attentional capture, demonstrating that in the absence of perceptual awareness, the visual system can extract behaviorally relevant details from a visual scene and automatically categorize threatening versus non-threatening images at a level of precision beyond our conscious perceptual capabilities. PMID:19523828

  4. Ethnic Differences in Physiological Responses to Fear Conditioned Stimuli

    PubMed Central

    Martínez, Karen G.; Franco-Chaves, José A.; Milad, Mohammed R.; Quirk, Gregory J.

    2014-01-01

    The idea that emotional expression varies with ethnicity is based largely on questionnaires and behavioral observations rather than physiological measures. We therefore compared the skin conductance responses (SCR) of Hispanic (Puerto Rican) and White non-Hispanic subjects in a fear conditioning and fear extinction task. Subjects were recruited from two sites: San Juan, Puerto Rico (PR), and Boston, Massachusetts (MA), using identical methods. A total of 78 healthy subjects (39 from PR, 39 from MA) were divided by sex and matched for age and educational level. Females from the two sites did not differ in their SCRs during any experimental phase of fear conditioning (habituation, conditioning, or extinction). In contrast, PR males responded significantly to the conditioned stimulus than MA males or PR females. Subtracting ethnic differences observed during the habituation phase (prior to conditioning) eliminated differences from subsequent phases, suggesting that PR males are elevated in their response to novelty rather than fear learning. Our findings suggest that, in addition to sex differences, there are ethnic differences in physiological responses to novel stimuli at least in males, which could be relevant for the assessment and treatment of anxiety disorders. PMID:25501365

  5. Visual anticipatory information modulates multisensory interactions of artificial audiovisual stimuli.

    PubMed

    Vroomen, Jean; Stekelenburg, Jeroen J

    2010-07-01

    The neural activity of speech sound processing (the N1 component of the auditory ERP) can be suppressed if a speech sound is accompanied by concordant lip movements. Here we demonstrate that this audiovisual interaction is neither speech specific nor linked to humanlike actions but can be observed with artificial stimuli if their timing is made predictable. In Experiment 1, a pure tone synchronized with a deformation of a rectangle induced a smaller auditory N1 than auditory-only presentations if the temporal occurrence of this audiovisual event was made predictable by two moving disks that touched the rectangle. Local autoregressive average source estimation indicated that this audiovisual interaction may be related to integrative processing in auditory areas. When the moving disks did not precede the audiovisual stimulus--making the onset unpredictable--there was no N1 reduction. In Experiment 2, the predictability of the leading visual signal was manipulated by introducing a temporal asynchrony between the audiovisual event and the collision of moving disks. Audiovisual events occurred either at the moment, before (too "early"), or after (too "late") the disks collided on the rectangle. When asynchronies varied from trial to trial--rendering the moving disks unreliable temporal predictors of the audiovisual event--the N1 reduction was abolished. These results demonstrate that the N1 suppression is induced by visual information that both precedes and reliably predicts audiovisual onset, without a necessary link to human action-related neural mechanisms.

  6. Auditory feature detection for stimuli presented from different directions

    NASA Astrophysics Data System (ADS)

    Bronkhorst, Adelbert W.; Townsend, James T.

    2002-05-01

    The processing of stimulus features by the visual system is commonly studied by measuring response times (RTs) for detection of targets presented with a varying number of distracters. In audition, however, interpretation of the interaction between target and distracters is complicated by effects like masking, binaural gain and fusion. In the present paradigm, which uses stimuli presented from different directions in the horizontal plane, these confounding effects were either minimized or kept constant. Targets were synthetic vowels and RTs were measured for detection of three features: F0, spectrum (type of vowel) and direction. Both single features and conjunctions were studied. Independent variables were the type of distracters (synthetic vowels or spectrally shaped noise) and their number. Results show that the effect of the number of distracters on the RT is smallest for the spectrum feature; RTs for the detection of F0 are largest and vary considerably across subjects. For conjunctions of features, the RTs lie, as expected, between the RTs for the single features. The effect of the type of distracter on the RT is small-this indicates that the processing involved in segregating vowels from noise is not more efficient than that used for segregating vowels from other vowels.

  7. Auditory Sensory Substitution is Intuitive and Automatic with Texture Stimuli

    PubMed Central

    Stiles, Noelle R. B.; Shimojo, Shinsuke

    2015-01-01

    Millions of people are blind worldwide. Sensory substitution (SS) devices (e.g., vOICe) can assist the blind by encoding a video stream into a sound pattern, recruiting visual brain areas for auditory analysis via crossmodal interactions and plasticity. SS devices often require extensive training to attain limited functionality. In contrast to conventional attention-intensive SS training that starts with visual primitives (e.g., geometrical shapes), we argue that sensory substitution can be engaged efficiently by using stimuli (such as textures) associated with intrinsic crossmodal mappings. Crossmodal mappings link images with sounds and tactile patterns. We show that intuitive SS sounds can be matched to the correct images by naive sighted participants just as well as by intensively-trained participants. This result indicates that existing crossmodal interactions and amodal sensory cortical processing may be as important in the interpretation of patterns by SS as crossmodal plasticity (e.g., the strengthening of existing connections or the formation of new ones), especially at the earlier stages of SS usage. An SS training procedure based on crossmodal mappings could both considerably improve participant performance and shorten training times, thereby enabling SS devices to significantly expand blind capabilities. PMID:26490260

  8. Satellite cell activity, without expansion, after nonhypertrophic stimuli.

    PubMed

    Joanisse, Sophie; McKay, Bryon R; Nederveen, Joshua P; Scribbans, Trisha D; Gurd, Brendon J; Gillen, Jenna B; Gibala, Martin J; Tarnopolsky, Mark; Parise, Gianni

    2015-11-01

    The purpose of the present studies was to determine the effect of various nonhypertrophic exercise stimuli on satellite cell (SC) pool activity in human skeletal muscle. Previously untrained men and women (men: 29 ± 9 yr and women: 29 ± 2 yr, n = 7 each) completed 6 wk of very low-volume high-intensity sprint interval training. In a separate study, recreationally active men (n = 16) and women (n = 3) completed 6 wk of either traditional moderate-intensity continuous exercise (n = 9, 21 ± 4 yr) or low-volume sprint interval training (n = 10, 21 ± 2 yr). Muscle biopsies were obtained from the vastus lateralis before and after training. The fiber type-specific SC response to training was determined, as was the activity of the SC pool using immunofluorescent microscopy of muscle cross sections. Training did not induce hypertrophy, as assessed by muscle cross-sectional area, nor did the SC pool expand in any group. However, there was an increase in the number of active SCs after each intervention. Specifically, the number of activated (Pax7(+)/MyoD(+), P ≤ 0.05) and differentiating (Pax7(-)/MyoD(+), P ≤ 0.05) SCs increased after each training intervention. Here, we report evidence of activated and cycling SCs that may or may not contribute to exercise-induced adaptations while the SC pool remains constant after three nonhypertrophic exercise training protocols.

  9. Stimuli-responsive gels as reaction vessels and reusable catalysts.

    PubMed

    Díaz Díaz, David; Kühbeck, Dennis; Koopmans, Rudy J

    2011-01-01

    As part of a continuing scientific challenge, a substantial effort during the past few decades has been devoted towards altering the selectivity of chemical transformations by arranging the potential reactants in a number of organized and confining media. Such systems, having features significantly different from those of isotropic solutions, include, for example, micelles, microemulsions, molecular aggregates, liquid crystals, and zeolites. Among these materials, stimuli-response gels constitute another important class of nanostructured and dynamic systems with high active surface areas and remarkable diffusion properties. Within this group, polymer gels have been traditionally used to obtain catalytic and reactive soft materials. Moreover, gels made of low-molecular-weight compounds represent a major novelty in this area as potential soft-vessels to carry out chemical reactions with control on product selectivity. In addition, the possibility of integrating switchable catalytic functions in both organo- and hydrogels shall accelerate the development of robust platforms for the 'bottom-up' tailor-fabrication of more sophisticated functional materials. The present critical review reports on the most important results published during the last decade regarding the use of 'smart' gels that has displayed promising properties as selective soft-nanoreactors and/or heterogeneous recyclable catalysts (152 references). PMID:20877874

  10. Neural markers of a greater female responsiveness to social stimuli

    PubMed Central

    Proverbio, Alice M; Zani, Alberto; Adorni, Roberta

    2008-01-01

    Background There is fMRI evidence that women are neurally predisposed to process infant laughter and crying. Other findings show that women might be more empathic and sensitive than men to emotional facial expressions. However, no gender difference in the brain responses to persons and unanimated scenes has hitherto been demonstrated. Results Twenty-four men and women viewed 220 images portraying persons or landscapes and ERPs were recorded from 128 sites. In women, but not in men, the N2 component (210–270) was much larger to persons than to scenes. swLORETA showed significant bilateral activation of FG (BA19/37) in both genders when viewing persons as opposed to scenes. Only women showed a source of activity in the STG and in the right MOG (extra-striate body area, EBA), and only men in the left parahippocampal area (PPA). Conclusion A significant gender difference was found in activation of the left and right STG (BA22) and the cingulate cortex for the subtractive condition women minus men, thus indicating that women might have a greater preference or interest for social stimuli (faces and persons). PMID:18590546

  11. Brief Emotion Regulation Training Facilitates Arousal Control During Sexual Stimuli.

    PubMed

    van Overveld, Mark; Borg, Charmaine

    2015-01-01

    Disgust, a negative emotion which evokes strong behavioral avoidance tendencies, has been associated with sexual dysfunction. Recently, it was postulated that healthy sexual functioning requires a balance between excitatory (increased sexual arousal) and inhibitory processes (lowered disgust levels). This suggests that amplification of excitatory processes (like sexual arousal) could be a valuable addition to treatments for affect-based sexual dysfunctions. The major aim of the present study was to establish whether up-regulation could effectively enhance arousal levels during sexual stimuli, and whether such a training would simultaneously reduce disgust. Students (N = 163, mean age = 20.73 years, SD = 2.35) were trained in up-regulation of affect using either a sexual arousal film (i.e., female-friendly erotic movie) or a threat arousal film clip (i.e., horror movie), while control groups viewed the films without training instructions. Following this, participants viewed and rated state emotions during a series of pictures (sexual, disgusting, or neutral). Up-regulation of mood successfully enhanced general arousal in both groups, yet these arousal levels were not paralleled by reductions in disgust. Overall, the findings indicate that emotion regulation training by maximizing positive affect and general arousal could be an effective instrument to facilitate affect-related disturbances in sexual dysfunctions.

  12. Hierarchical stimuli and hemispheric specialization: two case studies.

    PubMed

    Polster, M R; Rapcsak, S Z

    1994-09-01

    Local versus global visual processing was examined in two patients with massive unilateral left hemisphere lesions using a directed attention task involving hierarchical stimuli. Previous studies found an impressive global advantage in patients with posterior left hemisphere lesions on similar tasks. In addition, whereas patients with left inferior parietal lobule (IPL) lesions showed the global interference on local processing that is typically observed in normals, patients with lesions centered on the superior temporal gyrus (STG) demonstrated no interference. Paradoxically, our two patients who had complete destruction of both the left IPL and STG regions showed an overall local advantage due to local interference on global processing. We propose that following extensive left hemisphere damage, the isolated right hemisphere may be able to perform efficiently the type of processing usually ascribed to the left hemisphere (i.e., local). However, at least under certain conditions, this apparent functional plasticity seems to occur at the expense of the type of processing normally associated with the right hemisphere (i.e., global). PMID:7805389

  13. Stimuli of pepsinogen secretion from frog isolated peptic cells

    SciTech Connect

    Matsumoto, H.; Komiyama, K.; Shirakawa, T.; Heldman, A.; Anderson, W.; Hirschowitz, B.I.

    1986-03-05

    The authors have previously studied pepsinogen (Pg) secretion from isolated intact esophageal mucosa of the bullfrog R. catesbeiana. By stimulus-response studies using agonists and antagonists they characterized specific stimulation of cholinergic, adrenergic and peptidergic receptors and interaction of cAMP and Ca/sup 2 +/ dependent pathways. To understand cell mechanisms more definitively and to relate these to morphology it was necessary to isolate peptic cells. Esophageal mucosa was digested with 0.1% collagenase for 80-100 min and sieved through teflon mesh. One esophagus yielded approximately 10/sup 7/ cells, 70% pure and 89 +/- 5% viable. Basal secretion was 3% of Pg content/hr. The cells responded to graded concentrations of bombesin, bethanechol, IBMX, 8Br-cAMP, forskolin, TPA (12-0-tetradecanoyl phorbol 13 acetate) and A23187. The response to (TPA + A23187) was double the additive single output values; (TPA + A23187 + forskolin) stimulated secretion of more than double the sum of the 3 component stimuli. In calcium and magnesium-free medium, the A23187 response and the synergistic response of combinations were both lost. They have identified 3 messengers for Pg cell stimulation - cAMP, Ca/sup 2 +/ mobilization and protein kinase C - each of which can be separately stimulated, and when combined are strongly synergistic.

  14. Orbitofrontal response to drug-related stimuli after heroin administration.

    PubMed

    Walter, Marc; Denier, Niklaus; Gerber, Hana; Schmid, Otto; Lanz, Christian; Brenneisen, Rudolf; Riecher-Rössler, Anita; Wiesbeck, Gerhard A; Scheffler, Klaus; Seifritz, Erich; McGuire, Philip; Fusar-Poli, Paolo; Borgwardt, Stefan

    2015-05-01

    The compulsion to seek and use heroin is frequently driven by stress and craving during drug-cue exposure. Although previous neuroimaging studies have indicated that craving is mediated by increased prefrontal cortex activity, it remains unknown how heroin administration modulates the prefrontal cortex response. This study examines the acute effects of heroin on brain function in heroin-maintained patients. Using a crossover, double-blind, placebo-controlled design, 27 heroin-maintained patients performed functional magnetic resonance imaging 20 minutes after the administration of heroin or placebo (saline) while drug-related and neutral stimuli were presented. Images were processed and analysed with statistical parametric mapping. Plasma concentrations of heroin and its main metabolites were assessed using high-performance liquid chromatography. Region of interest analyses showed a drug-related cue-associated blood-oxygen-level-dependent activation in the orbitofrontal cortex (OFC) in heroin-dependent patients during both treatment conditions (heroin and placebo). This activation of the OFC was significantly higher after heroin than after placebo administration. These findings may indicate the importance of OFC activity for impulse control and decision-making after regular heroin administration and may emphasize the benefit of the heroin-assisted treatment in heroin dependence.

  15. Neural Correlates of the Perception of Spoiled Food Stimuli

    PubMed Central

    Becker, Christoph A.; Flaisch, Tobias; Renner, Britta; Schupp, Harald T.

    2016-01-01

    The elicitation of disgust by the view of spoiled and rotten foods is considered as an adaptation preventing the ingestion of harmful microorganisms and pathogens. To provide an effective behavioral defense, inedible food items need to be detected automatically, i.e., in the absence of explicit processing goals, early in the processing stream, and triggering an alarm response, i.e., increased attentional capture. To examine these hypotheses, a set of stimulus material consisting of images of perishable foods (i.e., dairies, meats, fruits, and vegetables) at various stages of natural decay ranging from appetitive to disgusting was developed. In separate sessions, functional imaging and dense sensor event related potential (ERP) data were collected while participants (N = 24) viewed the stimulus materials. Functional imaging data indicated larger activations in the extrastriate visual cortex during the processing of inedible as compared to edible food items. Furthermore, ERP recordings indicated that the processing of inedible food stimuli was associated with a relative positivity over inferior occipital sensor sites already at early stages of processing (<200 ms), and subsequently, an increased late positive potential (LPP) over parieto-occipital sensor regions. Taken together, these findings demonstrate the brain’s sensitivity to visual cues of foods that are spoiled or rotten. PMID:27445746

  16. The several roles of stimuli in token reinforcement.

    PubMed

    Bullock, Christopher E; Hackenberg, Timothy D

    2015-03-01

    Three experiments were conducted with pigeons to identify the stimulus functions of tokens in second-order token-reinforcement schedules. All experiments employed two-component multiple schedules with a token-reinforcement schedule in one component and a schedule with equivalent response requirements and/or reinforcer density in the other. In Experiment 1, response rates were lower under a token-reinforcement schedule than under a tandem schedule with the same response requirements, suggesting a discriminative role for the tokens. In Experiment 2, response rates varied systematically with signaling functions of the tokens in a series of conditions designed to explore other aspects of the temporal-correlative relations between tokens and food. In Experiment 3, response rates were reduced but not eliminated by presenting tokens independent of responding, yoked to their temporal occurrence in a preceding token component, suggesting both a reinforcing function and eliciting/evocative functions based on stimulus-food relations. Only when tokens were removed entirely was responding eliminated. On the whole, the results suggest that tokens, as stimuli temporally correlated with food, may serve multiple stimulus functions in token-reinforcement procedures--reinforcing, discriminative, or eliciting--depending on the precise arrangement of the contingencies in which they are embedded. PMID:25604188

  17. Olfactory classical conditioning in neonatal mouse pups using thermal stimuli.

    PubMed

    Bollen, Bieke; Matrot, Boris; Ramanantsoa, Nelina; Van den Bergh, Omer; D'Hooge, Rudi; Gallego, Jorge

    2012-04-01

    Mouse models are increasingly used to investigate genetic contributions to developmental disorders in children, especially newborns. In particular, early cognitive assessment in newborn mice is critical to evaluate pediatric drug efficacy and toxicity. Unfortunately, methods for behavioral tests in newborn mice are scarce. Therefore, developing such tests for newborn mice is a priority challenge for neurogenetics and pharmacological research. The aim of the present study was to develop a conditioning method well suited to high-throughput cognitive screening in newborn mice. To this end, we developed an odor-preference conditioning test using ambient temperature as an unconditioned stimulus (US) and artificial odors as conditioned stimuli (CS). First, we showed that mouse pups move toward the thermoneutral temperature when offered a choice between a thermoneutral and cold environment, thus showing thermotaxis. Second, we conducted a classical conditioning paradigm in pups aged six to ten days. In terms of central nervous system development, this period corresponds to extreme prematurity to early post-term period in humans. During acquisition, the pups were alternatively exposed to odor CS paired with either cold or warm temperatures. Immediately after acquisition, the pups underwent a two-odor choice test, which showed preference for the odor previously paired with the warm temperature, thus showing conditioning. The proposed paradigm is easy to conduct, and requires modest experimenter interference. The method is well suited for high-throughput screening of early associative disorders in newborn mice.

  18. Interhemispheric transfer and the processing of foveally presented stimuli.

    PubMed

    Brysbaert, M

    1994-10-20

    Two arguments are commonly given in favor of a nasotemporal overlap along the vertical meridian of the visual field: anatomical findings and the existence of macular sparing in hemianopia. A review of the literature, however, points to the weakness of the evidence. The anatomical indications are exclusively based on horseradish peroxidase studies, which can not give an unequivocal answer to the amount of overlap in central vision, and which were not supported by a recent study that made use of the more direct [14C]2-deoxy-D-glucose technique. The argument of macular sparing in hemianopia appears to be derived evidence that depends on the validity of the anatomical findings. In addition, behavioral studies consistently failed to find functional confirmation of the overlap. To further test the possibility of bilateral representation in central vision, a new paradigm is proposed. It is argued that if interhemispheric transfer is needed for the processing of foveally presented stimuli, the word-beginning superiority effect should be larger for subjects with left hemisphere dominance than for subjects with right hemisphere dominance. Results are in line with the hypothesis and point to the fact that interhemispheric transfer of visual information may be involved in more processing than usually accepted. It is also noted that transfer time seems to depend on the amount of information that must be transferred, and is significantly shorter than the estimates obtained in visual half field studies. PMID:7840882

  19. Neural Correlates of the Perception of Spoiled Food Stimuli.

    PubMed

    Becker, Christoph A; Flaisch, Tobias; Renner, Britta; Schupp, Harald T

    2016-01-01

    The elicitation of disgust by the view of spoiled and rotten foods is considered as an adaptation preventing the ingestion of harmful microorganisms and pathogens. To provide an effective behavioral defense, inedible food items need to be detected automatically, i.e., in the absence of explicit processing goals, early in the processing stream, and triggering an alarm response, i.e., increased attentional capture. To examine these hypotheses, a set of stimulus material consisting of images of perishable foods (i.e., dairies, meats, fruits, and vegetables) at various stages of natural decay ranging from appetitive to disgusting was developed. In separate sessions, functional imaging and dense sensor event related potential (ERP) data were collected while participants (N = 24) viewed the stimulus materials. Functional imaging data indicated larger activations in the extrastriate visual cortex during the processing of inedible as compared to edible food items. Furthermore, ERP recordings indicated that the processing of inedible food stimuli was associated with a relative positivity over inferior occipital sensor sites already at early stages of processing (<200 ms), and subsequently, an increased late positive potential (LPP) over parieto-occipital sensor regions. Taken together, these findings demonstrate the brain's sensitivity to visual cues of foods that are spoiled or rotten. PMID:27445746

  20. The Neural Response to Maternal Stimuli: An ERP Study

    PubMed Central

    Wu, Lili; Gu, Ruolei; Cai, Huajian; Luo, Yu L. L.; Zhang, Jianxin

    2014-01-01

    Mothers are important to all humans. Research has established that maternal information affects individuals' cognition, emotion, and behavior. We measured event-related potentials (ERPs) to examine attentional and evaluative processing of maternal stimuli while participants completed a Go/No-go Association Task that paired mother or others words with good or bad evaluative words. Behavioral data showed that participants responded faster to mother words paired with good than the mother words paired with bad but showed no difference in response to these others across conditions, reflecting a positive evaluation of mother. ERPs showed larger P200 and N200 in response to mother than in response to others, suggesting that mother attracted more attention than others. In the subsequent time window, mother in the mother + bad condition elicited a later and larger late positive potential (LPP) than it did in the mother + good condition, but this was not true for others, also suggesting a positive evaluation of mother. These results suggest that people differentiate mother from others during initial attentional stage, and evaluative mother positively during later stage. PMID:25375157

  1. Macular Preprocessing of Linear Acceleratory Stimuli: Implications for the Clinic

    NASA Technical Reports Server (NTRS)

    Ross, M. D.; Hargens, Alan R. (Technical Monitor)

    1996-01-01

    Three-dimensional reconstructions of innervation patterns in rat maculae were carried out using serial section images sent to a Silicon Graphics workstation from a transmission electron microscope. Contours were extracted from mosaicked sections, then registered and visualized using Biocomputation Center software. Purposes were to determine innervation patterns of type II cells and areas encompassed by vestibular afferent receptive fields. Terminals on type II cells typically are elongated and compartmentalized into parts varying in vesicular content; reciprocal and serial synapses are common. The terminals originate as processes of nearby calyces or from nerve fibers passing to calyces outside the immediate vicinity. Thus, receptive fields of the afferents overlap in unique ways. Multiple processes are frequent; from 4 to 6 afferents supply 12-16 terminals on a type II cell. Processes commonly communicate with two type II cells. The morphology indicates that extensive preprocessing of linear acceleratory stimuli occurs peripherally, as is true also of visual and olfactory systems. Clinically, this means that loss of individual nerve fibers may not be noticed behaviorally, due to redundancy (receptive field overlap). However, peripheral processing implies the presence of neuroactive agents whose loss can acutely or chronically alter normal peripheral function and cause balance disorders. (Platform presentation preferred - Theme 11)

  2. Stimuli-Responsive Theragrippers for Chemomechanical Controlled Release**

    PubMed Central

    Kwag, Hye Rin; Wang, Martha O.; Fisher, John P.; Selaru, Florin M.; Gracias, David H.

    2014-01-01

    We report on a therapeutic approach using thermo-responsive multi-fingered drug eluting devices. These therapeutic grippers referred to as theragrippers are shaped using photolithographic patterning and are composed of rigid poly(propylene fumarate) segments and stimuli responsive poly (N-isopropylacrylamide-co-acrylic acid) hinges. They close above 32°C allowing them to spontaneously grip onto tissue when introduced from a cold state into the body. Due to porosity in the grippers, theragrippers could also be loaded with fluorescent dyes and commercial drugs such as mesalamine and doxorubicin, which eluted from the grippers for up to seven days with first order release kinetics. In an in vitro model, theragrippers enhanced delivery of doxorubicin as compared to a control patch. We also released theragrippers into a live pig and visualized release of dye in the stomach. The design of such tissue gripping drug delivery devices offers an effective strategy for sustained release of drugs with immediate applicability in the gastrointestinal tract. PMID:24634136

  3. Brief Emotion Regulation Training Facilitates Arousal Control During Sexual Stimuli.

    PubMed

    van Overveld, Mark; Borg, Charmaine

    2015-01-01

    Disgust, a negative emotion which evokes strong behavioral avoidance tendencies, has been associated with sexual dysfunction. Recently, it was postulated that healthy sexual functioning requires a balance between excitatory (increased sexual arousal) and inhibitory processes (lowered disgust levels). This suggests that amplification of excitatory processes (like sexual arousal) could be a valuable addition to treatments for affect-based sexual dysfunctions. The major aim of the present study was to establish whether up-regulation could effectively enhance arousal levels during sexual stimuli, and whether such a training would simultaneously reduce disgust. Students (N = 163, mean age = 20.73 years, SD = 2.35) were trained in up-regulation of affect using either a sexual arousal film (i.e., female-friendly erotic movie) or a threat arousal film clip (i.e., horror movie), while control groups viewed the films without training instructions. Following this, participants viewed and rated state emotions during a series of pictures (sexual, disgusting, or neutral). Up-regulation of mood successfully enhanced general arousal in both groups, yet these arousal levels were not paralleled by reductions in disgust. Overall, the findings indicate that emotion regulation training by maximizing positive affect and general arousal could be an effective instrument to facilitate affect-related disturbances in sexual dysfunctions. PMID:25258109

  4. Retrospective Attention Gates Discrete Conscious Access to Past Sensory Stimuli

    PubMed Central

    Thibault, Louis; van den Berg, Ronald; Cavanagh, Patrick; Sergent, Claire

    2016-01-01

    Cueing attention after the disappearance of visual stimuli biases which items will be remembered best. This observation has historically been attributed to the influence of attention on memory as opposed to subjective visual experience. We recently challenged this view by showing that cueing attention after the stimulus can improve the perception of a single Gabor patch at threshold levels of contrast. Here, we test whether this retro-perception actually increases the frequency of consciously perceiving the stimulus, or simply allows for a more precise recall of its features. We used retro-cues in an orientation-matching task and performed mixture-model analysis to independently estimate the proportion of guesses and the precision of non-guess responses. We find that the improvements in performance conferred by retrospective attention are overwhelmingly determined by a reduction in the proportion of guesses, providing strong evidence that attracting attention to the target’s location after its disappearance increases the likelihood of perceiving it consciously. PMID:26863625

  5. Astrocytes Release Polyunsaturated Fatty Acids by Lipopolysaccharide Stimuli.

    PubMed

    Aizawa, Fuka; Nishinaka, Takashi; Yamashita, Takuya; Nakamoto, Kazuo; Koyama, Yutaka; Kasuya, Fumiyo; Tokuyama, Shogo

    2016-01-01

    We previously reported that levels of long-chain fatty acids (FAs) including docosahexaenoic acids (DHA) increase in the hypothalamus of inflammatory pain model mice. However, the precise mechanisms underlying the increment of free fatty acids (FFAs) in the brain during inflammation remains unknown. In this study, we characterized FFAs released by inflammatory stimulation in rat primary cultured astrocytes, and tested the involvement of phospholipase A2 (PLA2) on these mechanisms. Lipopolysaccharide (LPS) stimulation significantly increased the levels of several FAs in the astrocytes. Under these conditions, mRNA expression of cytosolic PLA2 (cPLA2) and calcium-independent PLA2 (iPLA2) in LPS-treated group increased compared with the control group. Furthermore, in the culture media, the levels of DHA and arachidonic acid (ARA) significantly increased by LPS stimuli compared with those of a vehicle-treated control group whereas the levels of saturated FAs (SFAs), namely palmitic acid (PAM) and stearic acid (STA), did not change. In summary, our findings suggest that astrocytes specifically release DHA and ARA by inflammatory conditions. Therefore astrocytes might function as a regulatory factor of DHA and ARA in the brain. PMID:27374285

  6. Habituation and the reinforcing effectiveness of visual stimuli.

    PubMed

    Lloyd, David R; Gancarz, Amy M; Ashrafioun, Lisham; Kausch, Michael A; Richards, Jerry B

    2012-10-01

    The term "sensory reinforcer" has been used to refer to sensory stimuli (e.g. light onset) that are primary reinforcers in order to differentiate them from other more biologically important primary reinforcers (e.g. food and water). Acquisition of snout poke responding for a visual stimulus (5 s light onset) with fixed ratio 1 (FR 1), variable-interval 1 min (VI 1 min), or variable-interval 6 min (VI 6 min) schedules of reinforcement was tested in three groups of rats (n=8/group). The VI 6 min schedule of reinforcement produced a higher response rate than the FR 1 or VI 1 min schedules of visual stimulus reinforcement. One explanation for greater responding on the VI 6 min schedule relative to the FR 1 and VI 1 min schedules is that the reinforcing effectiveness of light onset habituated more rapidly in the FR 1 and VI 1 min groups as compared to the VI 6 min group. The inverse relationship between response rate and the rate of visual stimulus reinforcement is opposite to results from studies with biologically important reinforcers which indicate a positive relationship between response and reinforcement rate. Rapid habituation of reinforcing effectiveness may be a fundamental characteristic of sensory reinforcers that differentiates them from biologically important reinforcers, which are required to maintain homeostatic balance.

  7. Hangover hyperthermia in rats: relation to tolerance and external stimuli.

    PubMed

    Sinclair, J D; Taira, T

    1988-01-01

    The recent finding of rebound hyperthermia in rats on the day after a single IP injection or oral intubation of ethanol was confirmed. In our studies, body temperature measured by rectal probe was significantly decreased for 8 h after 2.5 g/kg ethanol IP and was then significantly elevated 16-24 h after injection; increased vocalization during handling at 24 h was also found. However, rats isolated in a sound-attenuation chamber with remote temperature measurement showed no hyperthermia even though they were hypothermic during intoxication. The results do not support the hypothesis that rebound hyperthermia was caused by either a disruption of circadian rhythms, or by a mild abstinence syndrome alone. Instead, it appears that external stimuli, perhaps related to stress or associated with ethanol administration, are necessary on the day after a moderate dose of ethanol to produce the hyperthermia. Like hangover in humans, hyperthermia was reduced in rats made tolerant to ethanol: both the hypothermia and the rebound hyperthermia were significantly lower on the day after the 12th alternate-day ethanol injection than after the first injection. The aftereffects in rats of acute intoxication are, by definition, hangover signs, and they resemble hangover in humans in several ways, but their relevance as an animal model of hangover remains to be determined. PMID:3127841

  8. The BOSS and BIOMEX space experiments on the EXPOSE-R2 mission: Endurance of the desert cyanobacterium Chroococcidiopsis under simulated space vacuum, Martian atmosphere, UVC radiation and temperature extremes.

    NASA Astrophysics Data System (ADS)

    Baqué, Mickael; de Vera, Jean-Pierre; Rettberg, Petra; Billi, Daniela

    2013-10-01

    The proposed space experiments BOSS (Biofilm Organisms Surfing Space) and BIOMEX (BIOlogy and Mars experiment) will take place on the space exposure facility EXPOSE-R2 on the International Space Station (ISS), which is set to be launched in 2014. In BOSS the hypothesis to be tested is that microorganisms grown as biofilms, hence embedded in self-produced extracellular polymeric substances, are more tolerant to space and Martian conditions compared to their planktonic counterparts. Various microbial biofilms have been developed including those obtained from the cyanobacterium Chroococcidiopsis isolated from hot and cold deserts. The prime objective of BIOMEX is to evaluate to what extent biomolecules are resistant to, and can maintain their stability under, space and Mars-like conditions; therefore a variety of pigments and cell components are under investigation to establish a biosignature data base; e.g. a Raman spectral library to be used for extraterrestrial life biosignatures. The secondary objective of BIOMEX is to investigate the endurance of extremophiles, focusing on their interactions with Lunar and Martian mineral analogues. Ground-based studies are currently being carried out in the framework of EVTs (Experiment Verification Tests) by exposing selected organisms to space and Martian simulations. Results on a desert strain of Chroococcidiopsis obtained from the first set of EVT, e.g. space vacuum, Mars atmosphere, UVC radiation, temperature cycles and extremes, suggested that dried biofilms exhibited an enhanced survival compared to planktonic lifestyle. Moreover the protection provided by a Martian mineral analogue (S-MRS) to the sub-cellular integrities of Chroococcidiopsis against UVC radiation supports the endurance of this cyanobacterium under extraterrestrial conditions and its relevance in the development of life detection strategies.

  9. Development of silicon microforce sensors integrated with double meander springs for standard hardness test instruments

    NASA Astrophysics Data System (ADS)

    Wasisto, Hutomo Suryo; Doering, Lutz; Daus, Alwin; Brand, Uwe; Frank, Thomas; Peiner, Erwin

    2015-05-01

    Silicon microforce sensors, to be used as a transferable standard for micro force and depth scale calibrations of hardness testing instruments, are developed using silicon bulk micromachining technologies. Instead of wet chemical etching, inductively coupled plasma (ICP) cryogenic deep reactive ion etching (DRIE) is employed in the sensor fabrication process leading to more precise control of 300 μm deep structures with smooth sidewall profiles. Double meander springs are designed flanking to the boss replacing the conventional rectangular springs and thereby improving the system linearity. Two full p-SOI piezoresistive Wheatstone bridges are added on both clamped ends of the active sensors. To realize passive force sensors two spring-mass elements are stacked using glue and photoresist as joining materials. Correspondingly, although plastic deformation seems to occur when the second spring is contacted, the kink effect (i.e., abrupt increase of stiffness) is obviously observed from the first test of the passive stack sensor.

  10. Determination of myopes' visual acuity using stimuli with different contrast

    NASA Astrophysics Data System (ADS)

    Ikaunieks, G.; Caure, E.; Kassaliete, E.; Meskovska, Z.

    2012-10-01

    The influence of different contrast stimuli on the myopes’ visual acuity (VA) was studied using positive (35.7), negative (-0.97) and low contrast (-0.11) Landolt optotypes. Test subjects were 13 myopes with corrected eyesight and 8 emmetropes, all of them being 20-22 years old. For VA determination the FrACT computer program was employed. In the tests it was found that for emmetropes the positive and negative contrast VA values do not differ significantly, while for myopes the respective values are better with positive than with negative contrast stimuli. These differences were the same in the measurements taken with spectacles or contact lenses. Our results also show that the retinal straylight created by clean spectacles or soft contact lenses is similar in both cases. Dažu autoru pētījumi rāda, ka miopijas gadījumā redzes asums ir labāks ar pozitīva Vēbera kontrasta stimuliem (balts stimuls uz melna fona) nekā negatīva kontrasta stimuliem (melns stimuls uz balta fona). Šis fenomens tiek saistītas ar neirālām izmaiņām ON un OFF ceļos un miopiskās acīs. Citi pētījumi rāda, ka arī acī izkliedētās gaismas ietekmē labāks redzes asums ir ar pozitīviem kontrasta stimuliem nekā negatīva. Miopijas gadījumā papildus gaismas izkliedi rada briļļu lēcas vai kontaktlēcas. Mēs savā pētījumā vēlējāmies noskaidrot, cik lielā mērā labāks redzes asums ar pozitīva kontrasta stimuliem miopiskās acīs ir saistāms ar optiskās korekcijas radīto gaismas izkliedi. Pētījumā piedalījās 21 dalībnieks - 8 emetropi un 13 miopi ar sfērisko refrakcijas lielumu no -1.25 līdz -6,25 D. Dalībnieku vecums bija no 20 līdz 22 gadi. Izmantojot FrACT datorprogrammu, tika noteiks monokulārais redzes asums VA ar Landolta gredzeniem pie pozitīva, negatīva un zema kontrasta fotopiskos apstākļos. Vēbera kontrasti stimuliem attiecīgi bija 35.7, -0.97 un -0.11. Miopiem mērījumi tika veikti gan ar brillēm, gan

  11. Trained and Derived Relations with Pictures versus Abstract Stimuli as Nodes

    ERIC Educational Resources Information Center

    Arntzen, Erik; Lian, Torunn

    2010-01-01

    Earlier studies have shown divergent results concerning the use of familiar picture stimuli in demonstration of equivalence. In the current experiment, we trained 16 children to form three 3-member classes in a many-to-one training structure. Half of the participants were exposed first to a condition with all abstract stimuli and then to a…

  12. Natural stimuli improve auditory BCIs with respect to ergonomics and performance

    NASA Astrophysics Data System (ADS)

    Höhne, Johannes; Krenzlin, Konrad; Dähne, Sven; Tangermann, Michael

    2012-08-01

    Moving from well-controlled, brisk artificial stimuli to natural and less-controlled stimuli seems counter-intuitive for event-related potential (ERP) studies. As natural stimuli typically contain a richer internal structure, they might introduce higher levels of variance and jitter in the ERP responses. Both characteristics are unfavorable for a good single-trial classification of ERPs in the context of a multi-class brain-computer interface (BCI) system, where the class-discriminant information between target stimuli and non-target stimuli must be maximized. For the application in an auditory BCI system, however, the transition from simple artificial tones to natural syllables can be useful despite the variance introduced. In the presented study, healthy users (N = 9) participated in an offline auditory nine-class BCI experiment with artificial and natural stimuli. It is shown that the use of syllables as natural stimuli does not only improve the users’ ergonomic ratings; also the classification performance is increased. Moreover, natural stimuli obtain a better balance in multi-class decisions, such that the number of systematic confusions between the nine classes is reduced. Hopefully, our findings may contribute to make auditory BCI paradigms more user friendly and applicable for patients.

  13. Control by Contextual Stimuli in Novel Second-Order Conditional Discriminations

    ERIC Educational Resources Information Center

    Perez-Gonzalez, Luis Antonio; Martinez, Hector

    2007-01-01

    Eighteen undergraduates participated in studies designed to examine the factors that produce transfer of contextual functions to novel stimuli in second-order conditional discriminations. In Study 1, participants selected comparison B1 given sample A1 and comparison B2 given sample A2 in a matching-to-sample procedure. Contextual stimuli X1 or X2…

  14. Can Infants' Orientation to Social Stimuli Predict Later Joint Attention Skills?

    ERIC Educational Resources Information Center

    Schietecatte, Inge; Roeyers, Herbert; Warreyn, Petra

    2012-01-01

    From the moment infants are born, they seem to prefer orienting to social stimuli, over objects and non-social stimuli. This preference lasts throughout adulthood and is believed to play a crucial role in social-communicative development. By following up a group of infants at the age of 6, 8, and 12 months, this study explored the role of social…

  15. Auditory Attention to Frequency and Time: An Analogy to Visual Local-Global Stimuli

    ERIC Educational Resources Information Center

    Justus, Timothy; List, Alexandra

    2005-01-01

    Two priming experiments demonstrated exogenous attentional persistence to the fundamental auditory dimensions of frequency (Experiment 1) and time (Experiment 2). In a divided-attention task, participants responded to an independent dimension, the identification of three-tone sequence patterns, for both prime and probe stimuli. The stimuli were…

  16. A direct comparison of the taste of electrical and chemical stimuli.

    PubMed

    Stevens, David A; Baker, Diane; Cutroni, Elizabeth; Frey, Alexander; Pugh, David; Lawless, Harry T

    2008-06-01

    Three multidimensional scaling studies were conducted to compare the taste qualities evoked from electrical and chemical stimulation, including ferrous sulfate as a typical "metallic" taste stimulus. Bipolar, anodal, and cathodal stimulation were delivered by 1.5- or 3-V batteries applied to the tongue. Solutions of chemical stimuli including prototypical tastes and binary mixtures were evaporated on small metal disks to provide tactile impressions similar to those of the battery stimuli and avoid any potential response biases induced by the subjects' knowledge of the form of the stimulus. Multidimensional unfolding was performed to place stimuli and verbal descriptors in common perceptual spaces. Bipolar, anodal, and cathodal stimuli were tested in separate experiments but generated very similar perceptual spaces and were differentiated from the chemical stimuli. Electrical stimuli were associated with descriptors, such as metallic, copper penny, and iron nail, regardless of the polarity of stimulation. Taste qualities evoked by electric stimuli may not be fully described by commonly used taste stimuli or their binary mixtures and appear most adequately described by a unique metallic taste.

  17. Emotion Recognition in Animated Compared to Human Stimuli in Adolescents with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Brosnan, Mark; Johnson, Hilary; Grawmeyer, Beate; Chapman, Emma; Benton, Laura

    2015-01-01

    There is equivocal evidence as to whether there is a deficit in recognising emotional expressions in Autism spectrum disorder (ASD). This study compared emotion recognition in ASD in three types of emotion expression media (still image, dynamic image, auditory) across human stimuli (e.g. photo of a human face) and animated stimuli (e.g. cartoon…

  18. Effects of Social Stimuli on Laughing and Smiling in Young Children with Angelman Syndrome

    ERIC Educational Resources Information Center

    Richman, David M.; Gernat, Eric; Teichman, Heather

    2006-01-01

    The effects of social stimuli present and absent on laughing and smiling in 2 young children with Angelman syndrome were assessed via a multielement design. Results indicated that laughing and smiling for either child was unaffected by the social stimuli assessed in the social interaction condition. Results are discussed in terms of the effects of…

  19. A direct comparison of the taste of electrical and chemical stimuli.

    PubMed

    Stevens, David A; Baker, Diane; Cutroni, Elizabeth; Frey, Alexander; Pugh, David; Lawless, Harry T

    2008-06-01

    Three multidimensional scaling studies were conducted to compare the taste qualities evoked from electrical and chemical stimulation, including ferrous sulfate as a typical "metallic" taste stimulus. Bipolar, anodal, and cathodal stimulation were delivered by 1.5- or 3-V batteries applied to the tongue. Solutions of chemical stimuli including prototypical tastes and binary mixtures were evaporated on small metal disks to provide tactile impressions similar to those of the battery stimuli and avoid any potential response biases induced by the subjects' knowledge of the form of the stimulus. Multidimensional unfolding was performed to place stimuli and verbal descriptors in common perceptual spaces. Bipolar, anodal, and cathodal stimuli were tested in separate experiments but generated very similar perceptual spaces and were differentiated from the chemical stimuli. Electrical stimuli were associated with descriptors, such as metallic, copper penny, and iron nail, regardless of the polarity of stimulation. Taste qualities evoked by electric stimuli may not be fully described by commonly used taste stimuli or their binary mixtures and appear most adequately described by a unique metallic taste. PMID:18316314

  20. Sensitivity to Visual and Auditory Stimuli in Children with Developmental Dyslexia

    ERIC Educational Resources Information Center

    King, Bernardine; Wood, Clare; Faulkner, Dorothy

    2008-01-01

    This study considered the extent to which 23 children with dyslexia differed from 23 reading age (RA) and 23 chronological age (CA) matched controls in their ability to make temporal judgements about auditory and visual sequences of stimuli, and in the speed of their reactions to the onsets and offsets of visual and auditory stimuli. The children…

  1. Exploring the Development and Dismantling of Equivalence Classes Involving Terrorist Stimuli

    ERIC Educational Resources Information Center

    Dixon, Mark R.; Rehfeldt, Ruth Anne; Zlomke, Kimberly R.; Robinson, Ashton

    2006-01-01

    The present paper describes 2 studies that present a conceptual interpretation and experimental findings involving the developing and dismantling of equivalence classes consisting of terrorist stimuli. In the first study, 8 United States citizen participants were trained to match nonterrorist stimuli to American and terrorist images. Afterwards,…

  2. Conceptualizing Media Stimuli in Experimental Research: Psychological versus Attribute-Based Definitions

    ERIC Educational Resources Information Center

    Tao, Chen-Chao; Bucy, Erik P.

    2007-01-01

    This paper argues for a clearer conceptualization of media stimuli in experimental research and identifies 3 issues impeding our understanding of message processing: (a) assumptions bolstered by manipulation checks about homogeneity of response to media stimuli, (b) conflation of 2 different classes of variables--media attributes and psychological…

  3. Time and Number Discrimination in a Bisection Task with a Sequence of Stimuli: A Developmental Approach.

    ERIC Educational Resources Information Center

    Droit-Volet, Sylvie; Clement, Angelique; Fayol, Michel

    2003-01-01

    This study tested 5- and 8-year-olds and adults in a bisection task with a sequence of stimuli in which time and number co-varied. Findings indicated that the number of stimuli interfered with 5-year-olds' performance on the temporal bisection task. Number interference decreased both with age and counting strategy. In the numerical bisection task,…

  4. Description of a Practitioner Model for Identifying Preferred Stimuli with Individuals with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Karsten, Amanda M.; Carr, James E.; Lepper, Tracy L.

    2011-01-01

    The rich technology of stimulus preference assessment (SPA) is a product of 40 years of experimental research. Basic principles of reinforcement and a modest empirical literature suggest that high-preference stimuli identified via SPA may enhance treatment efficacy and decrease problem behavior more effectively than less-preferred stimuli. SPAs…

  5. Functional Hemispheric Differences for the Categorization of Global and Local Information in Naturalistic Stimuli

    ERIC Educational Resources Information Center

    Hubner, Ronald; Studer, Tobias

    2009-01-01

    Up to now functional hemispheric asymmetries for global/local processing have mainly been investigated with hierarchical letters as stimuli. In the present study, three experiments were conducted to examine whether corresponding visual-field (VF) effects can also be obtained with more naturalistic stimuli. To this end, images of animals with a…

  6. Attentional bias for positive emotional stimuli: A meta-analytic investigation.

    PubMed

    Pool, Eva; Brosch, Tobias; Delplanque, Sylvain; Sander, David

    2016-01-01

    Despite an initial focus on negative threatening stimuli, researchers have more recently expanded the investigation of attentional biases toward positive rewarding stimuli. The present meta-analysis systematically compared attentional bias for positive compared with neutral visual stimuli across 243 studies (N = 9,120 healthy participants) that used different types of attentional paradigms and positive stimuli. Factors were tested that, as postulated by several attentional models derived from theories of emotion, might modulate this bias. Overall, results showed a significant, albeit modest (Hedges' g = .258), attentional bias for positive as compared with neutral stimuli. Moderator analyses revealed that the magnitude of this attentional bias varied as a function of arousal and that this bias was significantly larger when the emotional stimulus was relevant to specific concerns (e.g., hunger) of the participants compared with other positive stimuli that were less relevant to the participants' concerns. Moreover, the moderator analyses showed that attentional bias for positive stimuli was larger in paradigms that measure early, rather than late, attentional processing, suggesting that attentional bias for positive stimuli occurs rapidly and involuntarily. Implications for theories of emotion and attention are discussed.

  7. The Use of Error Data to Study the Development of Verbal Encoding of Pictorial Stimuli.

    ERIC Educational Resources Information Center

    Cramer, Phebe

    If older children automatically label pictorial stimuli, then their performance should be impaired on tasks in which such labeling would increase the error rate. Children were asked to learn pairs of verbal or pictorial stimuli which, when combined, formed a different compound word (BUTTER-FLY). Subsequently, a false recognition test that included…

  8. Matching- and Nonmatching-to-Sample Concept Learning in Rats Using Olfactory Stimuli

    ERIC Educational Resources Information Center

    April, L. Brooke; Bruce, Katherine; Galizio, Mark

    2011-01-01

    Previous research has shown that rats can learn matching-to-sample relations with olfactory stimuli; however, the specific characteristics of this relational control are unclear. In Experiment 1, 6 rats were trained to either match or nonmatch to sample in a modified operant chamber using common household spices as olfactory stimuli. After…

  9. An Information-Processing Analysis of Children's Accuracy in Predicting the Appearance of Rotated Stimuli.

    ERIC Educational Resources Information Center

    Rosser, Rosemary A.; And Others

    1984-01-01

    The ability of 40 children four and five years of age to discriminate reflections and rotations of visual stimuli was examined in a kinetic imagery task. Results revealed that prediction accuracy was associated with the existence of orientation markers on the stimuli, as well as age, sex, type of discrimination, and several interactions among the…

  10. EFFECTS OF THREE DIFFERENT STIMULI ON THE CREATIVITY OF CHILDREN'S COMPOSITIONS.

    ERIC Educational Resources Information Center

    MAY, FRANK B.; TABACHNICK, B. ROBERT

    THIS STUDY BEGAN AN ATTEMPT TO DETERMINE THE BASIC CHARACTERISTICS OF EFFECTIVE MOTIVATING STIMULI FOR USE IN ELEMENTARY SCHOOL WRITING PROGRAMS. IN PARTICULAR, IT DEALT WITH THE EFFECTS OF ORGANIZED AND UNORGANIZED STIMULI ON THE CREATIVE WRITING ABILITY OF THIRD- AND SIXTH-GRADE STUDENTS. THE CHILDREN WERE DIVIDED INTO SIX GROUPS. ONE GROUP OF…

  11. Pupillary Reactivity to Emotional Stimuli in Children of Depressed and Anxious Mothers

    ERIC Educational Resources Information Center

    Burkhouse, Katie L.; Siegle, Greg J.; Gibb, Brandon E.

    2014-01-01

    Background: The primary aim of this study was to examine differences in physiological reactivity (measured via pupillometry) to emotional stimuli between children of depressed versus nondepressed mothers. A second goal was to examine differences in pupil dilation to emotional stimuli between children of anxious versus nonanxious mothers. Method:…

  12. Responses to moving small-field stimuli by the praying mantis, Sphodromantis lineola (Burmeister)

    PubMed

    Prete, F R; McLean, T; McMillin, P J

    1996-01-01

    Adult, female praying mantises, Sphodromantis lineola (Burmeister), were presented with mechanically driven or computer generated stimuli in a series of seven experiments in order to test several hypotheses regarding visual prey recognition. When presented with a series of square black and white computer generated stimuli against a white background, mantises performed the highest rates of predatory behavior in response to those stimuli with a greater proportion of black versus white pixels (i.e., those that produced larger luminance decrements). Higher response rates to computer generated stimuli that produced larger luminance decrements were also seen when the stimuli were irregularly shaped or consisted of two small synchronized stimuli. Mantises responded characteristically to mechanically driven stimuli that were camouflaged to match the background against which they moved, preferring small (vs. large) squares and rectangles that were elongated parallel (vs. perpendicular) to their direction of movement. Finally, response rate to a small, preferred mechanically presented or computer generated stimulus was suppressed by a concurrent large-field stimulus in inverse proportion to the distance between the two stimuli. This phenomenon is characteristic of systems that include phasic lateral inhibitory circuits. All of these results are consistent with the existence of a movement detector visual sub-system, as found in other orthopteromorph insects such as acridid grasshoppers and cockroaches. PMID:8834784

  13. The Effects on Visually Impaired Children of Viewing Fluorescent Stimuli under Black-Light Conditions.

    ERIC Educational Resources Information Center

    LaGrow, S. J.; Leung, J-P.; Leung, S.; Yeung, P.

    1998-01-01

    This study compared effects of four visual conditions of stimuli and light on the visual performance of 30 children with low vision (divided into high, and low, visual-acuity groups). Orange stimuli viewed under black light resulted in the best overall performance, benefitted the low-acuity group more than the high-acuity group, and was the…

  14. The Formation of Implicit and Explicit Attitudes for Neutral and Valenced Stimuli Using the Self

    ERIC Educational Resources Information Center

    Perugini, Marco; Richetin, Juliette; Zogmaister, Cristina

    2012-01-01

    In Evaluative Conditioning (EC) studies, novel Conditioned Stimuli (CSs) are usually selected so to be neutral. However, in real life, because of the tendency of humans to evaluate novel stimuli automatically, novel CSs are very often initially valenced. From the literature little is known on whether EC can be successful under these conditions. In…

  15. Resistance to Change and Frequency of Response-Dependent Stimuli Uncorrelated with Reinforcement

    ERIC Educational Resources Information Center

    Podlesnik, Christopher A.; Jimenez-Gomez, Corina; Ward, Ryan D.; Shahan, Timothy A.

    2009-01-01

    Stimuli uncorrelated with reinforcement have been shown to enhance response rates and resistance to disruption; however, the effects of different rates of stimulus presentations have not been assessed. In two experiments, we assessed the effects of adding different rates of response-dependent brief stimuli uncorrelated with primary reinforcement…

  16. Effects of Background Color on Detecting Spot Stimuli in the Upper and Lower Visual Fields

    ERIC Educational Resources Information Center

    Maehara, Goro; Okubo, Matia; Michimata, Chikashi

    2004-01-01

    Participants were required to detect spot stimuli briefly presented to the upper, central, or lower visual fields. The stimuli were presented either on a green or a red background. Results showed that reaction time (RT) was shorter for the lower visual field (LVF) compared to the upper visual field (UVF). Furthermore, this LVF advantage was…

  17. Rescuing Stimuli from Invisibility: Inducing a Momentary Release from Visual Masking with Pre-Target Entrainment

    ERIC Educational Resources Information Center

    Mathewson, Kyle E.; Fabiani, Monica; Gratton, Gabriele; Beck, Diane M.; Lleras, Alejandro

    2010-01-01

    At near-threshold levels of stimulation, identical stimulus parameters can result in very different phenomenal experiences. Can we manipulate which stimuli reach consciousness? Here we show that consciousness of otherwise masked stimuli can be experimentally induced by sensory entrainment. We preceded a backward-masked stimulus with a series of…

  18. Exposition of visual stimuli in an aversive situation and self-exposure to light in rats.

    PubMed

    Matysiak, J

    1978-01-01

    The aim of the work presented was to test the effect of associating visual stimuli with an aversive situation on later self-exposure to these stimuli. Forty-five male albino rats (Wistar) aged approximately 90 days were divided into three groups; visual trained in avoidance response to visual stimuli; auditory trained in avoidance response to auditory stimuli; and neutral untrained in avoidance response. In part two of the experiment all the rats were tested in a chamber for self-exposure to light. A statistically significant increase in the rewarding value of visual stimulation was found in the visual group in comparison with the remaining groups. This effect is interpreted as a result of extinction of anxiety response to visual stimuli as a result of which relaxation begins to positively reinforce the response leading to switching on the light.

  19. Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans.

    PubMed

    Saito, Atsuko; Mikami, Akichika; Hosokawa, Takayuki; Hasegawa, Toshikazu

    2006-02-01

    This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli. PMID:16671590

  20. Social attention with real versus reel stimuli: toward an empirical approach to concerns about ecological validity

    PubMed Central

    Risko, Evan F.; Laidlaw, Kaitlin E. W.; Freeth, Megan; Foulsham, Tom; Kingstone, Alan

    2012-01-01

    Cognitive neuroscientists often study social cognition by using simple but socially relevant stimuli, such as schematic faces or images of other people. Whilst this research is valuable, important aspects of genuine social encounters are absent from these studies, a fact that has recently drawn criticism. In the present review we argue for an empirical approach to the determination of the equivalence of different social stimuli. This approach involves the systematic comparison of different types of social stimuli ranging in their approximation to a real social interaction. In garnering support for this cognitive ethological approach, we focus on recent research in social attention that has involved stimuli ranging from simple schematic faces to real social interactions. We highlight both meaningful similarities and differences in various social attentional phenomena across these different types of social stimuli thus validating the utility of the research initiative. Furthermore, we argue that exploring these similarities and differences will provide new insights into social cognition and social neuroscience. PMID:22654747

  1. Effectiveness of three contingency-nonspecific stimuli on bathroom graffiti prevention in a college setting.

    PubMed

    Lee, Jin; Chung, Kyong-Mee

    2013-04-01

    An A-B-A design was adopted to test the effectiveness of different types of contingency-nonspecific stimuli in the prevention of bathroom graffiti in a college setting. The three stimuli examined in this study have been frequently used to prevent bathroom graffiti in South Korea and they were: (a) "Please do not write, draw, or mark on these walls;" (b) a mirror; and (c) "Courteous people keep public places clean." No graffiti was observed when the first and second stimuli were presented. In contrast, a notable increase in bathroom graffiti was observed when the third sign was presented. The results suggest that a contingency non-specific stimuli posting intervention can be effective in the prevention of bathroom graffiti only when appropriate stimuli are used. The practical implications, including cost-effectiveness, are discussed. PMID:23833871

  2. Agnosia for mirror stimuli: a new case report with a small parietal lesion.

    PubMed

    Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Lebas, Axel; Gerardin, Emmanuel; Hannequin, Didier

    2014-11-01

    Only seven cases of agnosia for mirror stimuli have been reported, always with an extensive lesion. We report a new case of an agnosia for mirror stimuli due to a circumscribed lesion. An extensive battery of neuropsychological tests and a new experimental procedure to assess visual object mirror and orientation discrimination were assessed 10 days after the onset of clinical symptoms, and 5 years later. The performances of our patient were compared with those of four healthy control subjects matched for age. This test revealed an agnosia for mirror stimuli. Brain imaging showed a small right occipitoparietal hematoma, encompassing the extrastriate cortex adjoining the inferior parietal lobe. This new case suggests that: (i) agnosia for mirror stimuli can persist for 5 years after onset and (ii) the posterior part of the right intraparietal sulcus could be critical in the cognitive process of mirror stimuli discrimination.

  3. Effectiveness of three contingency-nonspecific stimuli on bathroom graffiti prevention in a college setting.

    PubMed

    Lee, Jin; Chung, Kyong-Mee

    2013-04-01

    An A-B-A design was adopted to test the effectiveness of different types of contingency-nonspecific stimuli in the prevention of bathroom graffiti in a college setting. The three stimuli examined in this study have been frequently used to prevent bathroom graffiti in South Korea and they were: (a) "Please do not write, draw, or mark on these walls;" (b) a mirror; and (c) "Courteous people keep public places clean." No graffiti was observed when the first and second stimuli were presented. In contrast, a notable increase in bathroom graffiti was observed when the third sign was presented. The results suggest that a contingency non-specific stimuli posting intervention can be effective in the prevention of bathroom graffiti only when appropriate stimuli are used. The practical implications, including cost-effectiveness, are discussed.

  4. Viewing Sexual Stimuli Associated with Greater Sexual Responsiveness, Not Erectile Dysfunction

    PubMed Central

    Prause, Nicole; Pfaus, James

    2015-01-01

    Introduction Time spent viewing visual sexual stimuli (VSS) has the potential to habituate the sexual response and generalize to the partner context. Aim The aim of this study was to examine whether the time spent viewing VSS is related to sexual responsiveness felt in the laboratory or with a sexual partner. Methods Nontreatment-seeking men (N = 280) reported their weekly average VSS viewing in hours. VSS hours were examined in relation to the sexual arousal experienced while viewing a standardized sexual film in the laboratory and erectile problems experienced with a sexual partner. Main Outcome Measures Self-reported sexual arousal in response to sexual films and erectile problems on the International Index of Erectile Function were the main outcome measures. Results More hours viewing VSS was related to stronger experienced sexual responses to VSS in the laboratory, was unrelated to erectile functioning with a partner, and was related to stronger desire for sex with a partner. Conclusions VSS use within the range of hours tested is unlikely to negatively impact sexual functioning, given that responses actually were stronger in those who viewed more VSS. PMID:26185674

  5. Innovative testing of spatial ability: interactive responding and the use of complex stimuli material.

    PubMed

    Jelínek, Martin; Květon, Petr; Vobořil, Dalibor

    2015-02-01

    Despite initial expectations, which have emerged with the advancement of computer technology over the last decade of the twentieth century, scientific literature does not contain many relevant references regarding the development and use of innovative items in psychological testing. Our study presents and evaluates two novel item types. One item type is derived from a standard schematic test item used for the assessment of the spatial perception aspect of spatial ability, enhanced by an interactive response module. The performance on this item type is correlated with the performance on its paper and pencil counterpart. The other innovative item type used complex stimuli in the form of a short video of a ride through a city presented in an on-route perspective, which is intended to measure navigation skills and the ability to keep oneself oriented in space. In this case, the scores were related to the capacity of visuo-spatial working memory and also to the overall score in the paper/pencil test of spatial ability. The second relationship was moderated by gender.

  6. A psychometric evaluation of cigarette stimuli used in a cue reactivity study.

    PubMed

    Carter, Brian L; Robinson, Jason D; Lam, Cho Y; Wetter, David W; Tsan, Jack Y; Day, Susan X; Cinciripini, Paul M

    2006-06-01

    Laboratory studies have demonstrated that cigarette smokers react with significant subjective and autonomic responses (e.g., increased craving and increased heart rate) in the presence of stimuli associated with smoking. Although cue reactivity effects are typically robust, a number of methodological considerations make interpretation and design of cue reactivity studies problematic. Previous research has paid scant attention to the psychometric properties of the cigarette cues presented, and standard cues would enhance comparison and synthesis of studies. In the present study, we evaluated 12 cigarette photos (compared with positive, negative, and neutral photos), used in a separate study, for their ability to evoke self-report of craving in both nicotine-deprived and nondeprived smokers. These photos performed as expected, with cigarette pictures evoking significantly higher craving than neutral pictures and deprived smokers showing a trend toward higher craving than nondeprived smokers. The cigarette picture set was evaluated for internal consistency (Cronbach's alpha = .97) as a 12-item scale and further reduced to multiple 2-item scales with reliability estimates ranging from .70 to .93. A cluster analysis of all pictures showed that, when rated for craving, cigarette pictures clustered together, indicating they had distinct properties compared with positive, negative, and neutral pictures. Effect sizes were calculated for each cigarette picture in both deprived and nondeprived smokers. The craving effect sizes ranged from .57 to .98 for nondeprived smokers, and from .61 to .99 for deprived smokers. The analyses suggest these cigarette pictures have excellent psychometric properties for use in future cue reactivity studies.

  7. A paradigm change: efficient transfection of human leukemia cells by stimuli-responsive multicompartment micelles.

    PubMed

    Rinkenauer, Alexandra C; Schallon, Anja; Günther, Ulrike; Wagner, Michael; Betthausen, Eva; Schubert, Ulrich S; Schacher, Felix H

    2013-11-26

    The controlled nonviral delivery of genetic material using cationic polymers into cells has been of interest during the past three decades, yet the ideal delivery agent featuring utmost transfection efficiency and low cytotoxicity still has to be developed. Here, we demonstrate that multicompartment micelles from stimuli-responsive triblock terpolymers, polybutadiene-block-poly(methacrylic acid)-block-poly(2-(dimethylamino)ethyl methacrylate) (BMAAD), are promising candidates. The structures exhibit a patchy shell, consisting of amphiphilic (interpolyelectrolyte complexes, MAA and D) and cationic patches (excess D), generating a surface reminiscent to those of certain viruses and capable of undergoing pH-dependent changes in charge stoichiometry. After polyplex formation with plasmid DNA, superior transfection efficiencies can be reached for both adherent cells and human leukemia cells. Compared to the gold standard PEI, remarkable improvements and a number of advantages were identified for this system, including increased cellular uptake and an improved release of the genetic material, accompanied by fast and efficient endosomal escape. Furthermore, high sedimentation rates might be beneficial regarding in vitro applications. PMID:24147450

  8. The I' potential of the human auditory brainstem response to paired click stimuli.

    PubMed

    Davis-Gunter, M J; Löwenheim, H; Gopal, K V; Moore, E J

    2001-01-01

    When stimulated with an appropriate stimulus, the hair cells of the organ of Corti depolarize, causing the release of a neurotransmitter substance, which excites afferent VIIIth nerve dendrites. It is reasonable to hypothesize that excitatory postsynaptic potentials (EPSPs) generated by the dendrites of the auditory nerve in turn initiate a compound action potential (CAP). The EPSP is thought to be the generator potential for the CAP, and may be recorded in auditory brainstem responses (ABRs) as the I' potential. Determining the anatomical origin of I' may enhance the sensitivity of the ABR technique in hair cell/dendrite/auditory nerve evaluations. Whether I' is of sensory or of neural origin is equivocal, and therefore I' is not well understood. To investigate this dilemma, ABRs were recorded from human subjects using standard and paired-click stimuli, and using subtraction methods to generate a derived ABR. Two early peaks, designated as I degree and I', occurred before wave I in the derived ABR. It was hypothesized that peaks I degrees and I' represent the summating potential and the generator potential, generated by the cochlea and VIIIth nerve dendrites, respectively.

  9. Visual and auditory stimuli associated with swallowing activate mirror neurons: a magnetoencephalography study.

    PubMed

    Ushioda, Takashi; Watanabe, Yutaka; Sanjo, Yusuke; Yamane, Gen-Yuki; Abe, Shinichi; Tsuji, Yusuke; Ishiyama, Atushi

    2012-12-01

    In the present study, we evaluated activated areas of the cerebral cortex with regard to the mirror neuron system during swallowing. To identify the activated areas, we used magnetoencephalography. Subjects were ten consenting volunteers. Swallowing-related stimuli comprised an animated image of the left profile of a person swallowing water with laryngeal elevation as a visual swallowing trigger stimulus and a swallowing sound as an auditory swallowing trigger stimulus. As control stimuli, a still frame image of the left profile without an additional trigger was shown, and an artificial sound as a false auditory trigger was provided. Triggers were presented at 3,000 ms after the start of image presentation. The stimuli were combined and presented and the areas activated were identified for each stimulus. With animation and still-frame stimuli, the visual association area (Brodmann area (BA) 18) was activated at the start of image presentation, while with the swallowing sound and artificial sound stimuli, the auditory areas BA 41 and BA 42 were activated at the time of trigger presentation. However, with animation stimuli (animation stimulus, animation + swallowing sound stimuli, and animation + artificial sound stimuli), activation in BA 6 and BA 40, corresponding to mirror neurons, was observed between 620 and 720 ms before the trigger. Besides, there were also significant differences in latency time and peak intensity between animation stimulus and animation + swallowing sound stimuli. Our results suggest that mirror neurons are activated by swallowing-related visual and auditory stimuli.

  10. First- and Second-Order Stimuli Reaction Time Measures Are Highly Sensitive to Mild Traumatic Brain Injuries.

    PubMed

    Piponnier, Jean-Claude; Forget, Robert; Gagnon, Isabelle; McKerral, Michelle; Giguère, Jean-François; Faubert, Jocelyn

    2016-01-15

    Mild traumatic brain injury (mTBI) has subtle effects on several brain functions that can be difficult to assess and follow up. We investigated the impact of mTBI on the perception of sine-wave gratings defined by first- and second-order characteristics. Fifteen adults diagnosed with mTBI were assessed at 15 days, 3 months, and 12 months postinjury. Fifteen matched controls followed the same testing schedule. Reaction times (RTs) for flicker detection and motion direction discrimination were measured. Stimulus contrast of first- and second-order patterns was equated to control for visibility, and correct-response RT means, standard deviations (SDs), medians, and interquartile ranges (IQRs) were calculated. The level of symptoms was also evaluated to compare it to RT data. In general in mTBI, RTs were longer, and SDs as well as IQRs larger, than those of controls. In addition, mTBI participants' RTs to first-order stimuli were shorter than those to second-order stimuli, and SDs as well as IQRs larger for first- than for second-order stimuli in the motion condition. All these observations were made over the three sessions. The level of symptoms observed in mTBI was higher than that of control participants, and this difference did also persist up to 1 year after the brain injury, despite an improvement. The combination of RT measures with particular stimulus properties is a highly sensitive method for measuring mTBI-induced visuomotor anomalies and provides a fine probe of the underlying mechanisms when the brain is exposed to mild trauma.

  11. A sequential pulse generator for producing true biphasic stimuli.

    PubMed

    Mitz, A R; Reed, D J; Humphrey, D R

    1984-06-01

    The ability to generate biphasic pulses during electrical stimulation of nervous tissue has important advantages over monophasic or capacitively coupled stimulation. A comparatively simple circuit is described which, when used with standard electrophysiological laboratory equipment, can economically implement biphasic stimulation. The resultant system is quite flexible, yet easy to operate.

  12. Auditory ERP response to successive stimuli in infancy.

    PubMed

    Chen, Ao; Peter, Varghese; Burnham, Denis

    2016-01-01

    Background. Auditory Event-Related Potentials (ERPs) are useful for understanding early auditory development among infants, as it allows the collection of a relatively large amount of data in a short time. So far, studies that have investigated development in auditory ERPs in infancy have mainly used single sounds as stimuli. Yet in real life, infants must decode successive rather than single acoustic events. In the present study, we tested 4-, 8-, and 12-month-old infants' auditory ERPs to musical melodies comprising three piano notes, and examined ERPs to each individual note in the melody. Methods. Infants were presented with 360 repetitions of a three-note melody while EEG was recorded from 128 channels on the scalp through a Geodesic Sensor Net. For each infant, both latency and amplitude of auditory components P1 and N2 were measured from averaged ERPs for each individual note. Results. Analysis was restricted to response collected at frontal central site. For all three notes, there was an overall reduction in latency for both P1 and N2 over age. For P1, latency reduction was significant from 4 to 8 months, but not from 8 to 12 months. N2 latency, on the other hand, decreased significantly from 4 to 8 to 12 months. With regard to amplitude, no significant change was found for either P1 or N2. Nevertheless, the waveforms of the three age groups were qualitatively different: for the 4-month-olds, the P1-N2 deflection was attenuated for the second and the third notes; for the 8-month-olds, such attenuation was observed only for the middle note; for the 12-month-olds, the P1 and N2 peaks show relatively equivalent amplitude and peak width across all three notes. Conclusion. Our findings indicate that the infant brain is able to register successive acoustic events in a stream, and ERPs become better time-locked to each composite event over age. Younger infants may have difficulties in responding to late occurring events in a stream, and the onset response to the

  13. Polymeric variable optical attenuators based on magnetic sensitive stimuli materials

    NASA Astrophysics Data System (ADS)

    de Pedro, S.; Cadarso, V. J.; Ackermann, T. N.; Muñoz-Berbel, X.; Plaza, J. A.; Brugger, J.; Büttgenbach, S.; Llobera, A.

    2014-12-01

    Magnetically-actuable, polymer-based variable optical attenuators (VOA) are presented in this paper. The design comprises a cantilever which also plays the role of a waveguide and the input/output alignment elements for simple alignment, yet still rendering an efficient coupling. Magnetic properties have been conferred to these micro-opto-electromechanical systems (MOEMS) by implementing two different strategies: in the first case, a magnetic sensitive stimuli material (M-SSM) is obtained by a combination of polydimethylsiloxane (PDMS) and ferrofluid (FF) in ratios between 14.9 wt % and 29.9 wt %. An M-SSM strip under the waveguide-cantilever, defined with soft lithography (SLT), provides the required actuation capability. In the second case, specific volumes of FF are dispensed at the end of the cantilever tip (outside the waveguide) by means of inkjet printing (IJP), obtaining the required magnetic response while holding the optical transparency of the waveguide-cantilever. In the absence of a magnetic field, the waveguide-cantilever is aligned with the output fiber optics and thus the intrinsic optical losses can be obtained. Numerical simulations, validated experimentally, have shown that, for any cantilever length, the VOAs defined by IJP present lower intrinsic optical losses than their SLT counterparts. Under an applied magnetic field (Bapp), both VOA configurations experience a misalignment between the waveguide-cantilever and the output fiber optics. Thus, the proposed VOAs modulate the output power as a function of the cantilever displacement, which is proportional to Bapp. The experimental results for the three different waveguide-cantilever lengths and six different FF concentrations (three per technology) show maximum deflections of 220 µm at 29.9 wt % of FF for VOASLT and 250 µm at 22.3 wt % FF for VOAIJP, at 0.57 kG for both. These deflections provide maximum actuation losses of 16.1 dB and 18.9 dB for the VOASLT and VOAIJP

  14. Auditory ERP response to successive stimuli in infancy

    PubMed Central

    Peter, Varghese; Burnham, Denis

    2016-01-01

    Background. Auditory Event-Related Potentials (ERPs) are useful for understanding early auditory development among infants, as it allows the collection of a relatively large amount of data in a short time. So far, studies that have investigated development in auditory ERPs in infancy have mainly used single sounds as stimuli. Yet in real life, infants must decode successive rather than single acoustic events. In the present study, we tested 4-, 8-, and 12-month-old infants’ auditory ERPs to musical melodies comprising three piano notes, and examined ERPs to each individual note in the melody. Methods. Infants were presented with 360 repetitions of a three-note melody while EEG was recorded from 128 channels on the scalp through a Geodesic Sensor Net. For each infant, both latency and amplitude of auditory components P1 and N2 were measured from averaged ERPs for each individual note. Results. Analysis was restricted to response collected at frontal central site. For all three notes, there was an overall reduction in latency for both P1 and N2 over age. For P1, latency reduction was significant from 4 to 8 months, but not from 8 to 12 months. N2 latency, on the other hand, decreased significantly from 4 to 8 to 12 months. With regard to amplitude, no significant change was found for either P1 or N2. Nevertheless, the waveforms of the three age groups were qualitatively different: for the 4-month-olds, the P1–N2 deflection was attenuated for the second and the third notes; for the 8-month-olds, such attenuation was observed only for the middle note; for the 12-month-olds, the P1 and N2 peaks show relatively equivalent amplitude and peak width across all three notes. Conclusion. Our findings indicate that the infant brain is able to register successive acoustic events in a stream, and ERPs become better time-locked to each composite event over age. Younger infants may have difficulties in responding to late occurring events in a stream, and the onset response to

  15. EOS standards

    SciTech Connect

    Greeff, Carl W

    2011-01-12

    An approach to creating accurate EOS for pressure standards is described. Applications to Cu, Au, and Ta are shown. Extension of the method to high compressions using DFT is illustrated. Comparisons with modern functionals show promise.

  16. (Terminology standardization)

    SciTech Connect

    Strehlow, R.A.

    1990-10-19

    Terminological requirements in information management was but one of the principal themes of the 2nd Congress on Terminology and Knowledge Engineering. The traveler represented the American Society for Testing and Materials' Committee on Terminology, of which he is the Chair. The traveler's invited workshop emphasized terminology standardization requirements in databases of material properties as well as practical terminology standardizing methods. The congress included six workshops in addition to approximately 82 lectures and papers from terminologists, artificial intelligence practitioners, and subject specialists from 18 countries. There were approximately 292 registrants from 33 countries who participated in the congress. The congress topics were broad. Examples were the increasing use of International Standards Organization (ISO) Standards in legislated systems such as the USSR Automated Data Bank of Standardized Terminology, the enhanced Physics Training Program based on terminology standardization in Physics in the Chinese province of Inner Mongolia, and the technical concept dictionary being developed at the Japan Electronic Dictionary Research Institute, which is considered to be the key to advanced artificial intelligence applications. The more usual roles of terminology work in the areas of machine translation. indexing protocols, knowledge theory, and data transfer in several subject specialties were also addressed, along with numerous special language terminology areas.

  17. Comparison of EEG propagation speeds under emotional stimuli on smartphone between the different anxiety states

    PubMed Central

    Asakawa, Tetsuya; Muramatsu, Ayumi; Hayashi, Takuto; Urata, Tatsuya; Taya, Masato; Mizuno-Matsumoto, Yuko

    2014-01-01

    The current study evaluated the effect of different anxiety states on information processing as measured by an electroencephalography (EEG) using emotional stimuli on a smartphone. Twenty-three healthy subjects were assessed for their anxiety states using The State Trait Anxiety Inventory (STAI) and divided into two groups: low anxiety (I, II) or high anxiety (III and IV, V). An EEG was performed while the participant was presented with emotionally laden audiovisual stimuli (resting, pleasant, and unpleasant sessions) and emotionally laden sentence stimuli (pleasant sentence, unpleasant sentence sessions) and EEG data was analyzed using propagation speed analysis. The propagation speed of the low anxiety group at the medial coronal for resting stimuli for all time segments was higher than those of high anxiety group. The low anxiety group propagation speeds at the medial sagittal for unpleasant stimuli in the 0–30 and 60–150 s time frames were higher than those of high anxiety group. The propagation speeds at 150 s for all stimuli in the low anxiety group were significantly higher than the correspondent propagation speeds of the high anxiety group. These events suggest that neural information processes concerning emotional stimuli differ based on current anxiety state. PMID:25540618

  18. The Value of Social Attributes of Stimuli for Promoting Engagement in Persons With Dementia

    PubMed Central

    Cohen-Mansfield, Jiska; Thein, Khin; Dakheel-Ali, Maha; Regier, Natalie G.; Marx, Marcia S.

    2011-01-01

    The present study examined the impact of different attributes of social stimuli using the stimulus attributes aspect of the Comprehensive Process Model of Engagement (Cohen-Mansfield et al., (2009a) Am J Geriatr Psychiatry. 17:299–307). Participants were 193 residents of 7 Maryland nursing homes with a diagnosis of dementia. Stimuli were chosen to represent different levels of the following social attributes: social versus not social, realistic versus not realistic, animated versus nonanimated, human versus nonhuman, and alive versus not alive. Participants had significantly longer engagement, were significantly more attentive, and displayed a significantly more positive attitude with social stimuli than with nonsocial stimuli. Longer durations and higher ratings of attention and attitude were seen with realistic and animated stimuli as compared to their counterparts. Human and live stimuli resulted in significantly more engagement than their counterparts. Giving any social stimulus to the residents is preferable to providing none, and the social attributes of stimuli should be maximized. PMID:20699725

  19. Resistance to change and frequency of response-dependent stimuli uncorrelated with reinforcement.

    PubMed

    Podlesnik, Christopher A; Jimenez-Gomez, Corina; Ward, Ryan D; Shahan, Timothy A

    2009-09-01

    Stimuli uncorrelated with reinforcement have been shown to enhance response rates and resistance to disruption; however, the effects of different rates of stimulus presentations have not been assessed. In two experiments, we assessed the effects of adding different rates of response-dependent brief stimuli uncorrelated with primary reinforcement on relative response rates and resistance to change. In both experiments, pigeons responded on variable-interval 60-s schedules of food reinforcement in two components of a multiple schedule, and brief response-dependent keylight-color changes were added to one or both components. Although relative response rates were not systematically affected in either experiment, relative resistance to presession feeding and extinction were. In Experiment 1, adding stimuli on a variable-interval schedule to one component of a multiple schedule either at a low rate (1 per min) for one group or at a high rate (4 per min) for another group similarly increased resistance to disruption in the components with added stimuli. When high and low rates of stimuli were presented across components (i.e., within subjects) in Experiment 2, however, relative resistance to disruption was greater in the component presenting stimuli at a lower rate. These results suggest that stimuli uncorrelated with food reinforcement do not strengthen responding in the same way as primary reinforcers.

  20. Human hypothalamus shows differential responses to basic motivational stimuli--an invasive electrophysiology study.

    PubMed

    Nager, W; Krauss, J K; Heldmann, M; Marco-Pallares, J; Capelle, H-H; Lütjens, G; Bolat, S; Dengler, R; Münte, T F

    2011-08-25

    The hypothalamus supports basic motivational behaviours such as mating and feeding. Recording directly from the posterior inferior hypothalamus in a male patient receiving a deep brain stimulation (DBS) electrode for the alleviation of cluster headache, we tested the hypothalamic response to different classes of motivational stimuli (sexually relevant: pictures of dressed and undressed women; pictures of food) and pictures of common objects as control. Averaged local field potentials (LFP) to sexually relevant stimuli were characterized by a biphasic significantly enhanced response (relative to objects; bootstrapping statistics) with a first phase starting at around 200 ms and a second phase peaking at around 600 ms. Sexually relevant stimuli also showed a greatly enhanced positivity relative to other stimulus classes in surface event-related potentials in a group of 11 male control participants. It is suggested that the hypothalamus is involved in the recruitment of attentional resources by sexually relevant stimuli reflected in this surface positivity. In a second session, the response to food stimuli relative to objects was tested in two states: after fasting for 14 h, LFPs to food and object stimuli showed significant differences in between 300 and 850 ms, which disappeared after a full high-calorie meal, thus replicating classic studies in monkeys [Rolls et al., Brain Res (1976) 111:53-66]. The current data are the first to demonstrate hypothalamic responses to the sight of motivational stimuli in man and thus shows that recording from DBS electrodes might provide important information about the cognitive functions of subcortical structures. PMID:21651964