WorldWideScience

Sample records for non-mirror image stimuli

  1. Posturographic destabilization in eating disorders in female patients exposed to body image related phobic stimuli.

    Science.gov (United States)

    Forghieri, M; Monzani, D; Mackinnon, A; Ferrari, S; Gherpelli, C; Galeazzi, G M

    2016-08-26

    Human postural control is dependent on the central integration of vestibular, visual and proprioceptive inputs. Psychological states can affect balance control: anxiety, in particular, has been shown to influence balance mediated by visual stimuli. We hypothesized that patients with eating disorders would show postural destabilization when exposed to their image in a mirror and to the image of a fashion model representing their body ideal in comparison to body neutral stimuli. Seventeen females patients attending a day centre for the treatment of eating disorders were administered psychometric measures of body dissatisfaction, anxiety, depression and underwent posturographic measures with their eyes closed, open, watching a neutral stimulus, while exposed to a full length mirror and to an image of a fashion model corresponding to their body image. Results were compared to those obtained by eighteen healthy subjects. Eating disordered patients showed higher levels of body dissatisfaction and higher postural destabilization than controls, but this was limited to the conditions in which they were exposed to their mirror image or a fashion model image. Postural destabilization under these conditions correlated with measures of body dissatisfaction. In eating disordered patients, body related stimuli seem to act as phobic stimuli in the posturographic paradigm used. If confirmed, this has the potential to be developed for diagnostic and therapeutic purposes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Retinal image quality and visual stimuli processing by simulation of partial eye cataract

    Science.gov (United States)

    Ozolinsh, Maris; Danilenko, Olga; Zavjalova, Varvara

    2016-10-01

    Visual stimuli were demonstrated on a 4.3'' mobile phone screen inside a "Virtual Reality" adapter that allowed separation of the left and right eye visual fields. Contrast of the retina image thus can be controlled by the image on the phone screen and parallel to that at appropriate geometry by the AC voltage applied to scattering PDLC cell inside the adapter. Such optical pathway separation allows to demonstrate to both eyes spatially variant images, that after visual binocular fusion acquire their characteristic indications. As visual stimuli we used grey and different color (two opponent components to vision - red-green in L*a*b* color space) spatially periodical stimuli for left and right eyes; and with spatial content that by addition or subtraction resulted as clockwise or counter clockwise slanted Gabor gratings. We performed computer modeling with numerical addition or subtraction of signals similar to processing in brain via stimuli input decomposition in luminance and color opponency components. It revealed the dependence of the perception psychophysical equilibrium point between clockwise or counter clockwise perception of summation on one eye image contrast and color saturation, and on the strength of the retinal aftereffects. Existence of a psychophysical equilibrium point in perception of summation is only in the presence of a prior adaptation to a slanted periodical grating and at the appropriate slant orientation of adaptation grating and/or at appropriate spatial grating pattern phase according to grating nods. Actual observer perception experiments when one eye images were deteriorated by simulated cataract approved the shift of mentioned psychophysical equilibrium point on the degree of artificial cataract. We analyzed also the mobile devices stimuli emission spectra paying attention to areas sensitive to macula pigments absorption spectral maxima and blue areas where the intense irradiation can cause in abnormalities in periodic melatonin

  3. Correction: Stimuli-responsive magnetic nanoparticles for tumor-targeted bimodal imaging and photodynamic/hyperthermia combination therapy

    Science.gov (United States)

    Kim, Kyoung Sub; Kim, Jiyoung; Lee, Joo Young; Matsuda, Shofu; Hideshima, Sho; Mori, Yasurou; Osaka, Tetsuya; Na, Kun

    2016-06-01

    Correction for `Stimuli-responsive magnetic nanoparticles for tumor-targeted bimodal imaging and photodynamic/hyperthermia combination therapy' by Kyoung Sub Kim, et al., Nanoscale, 2016, DOI: 10.1039/c6nr02273a.

  4. Dynamic contrast-enhanced photoacoustic imaging using photothermal stimuli-responsive composite nanomodulators

    Science.gov (United States)

    Chen, Yun-Sheng; Yoon, Soon Joon; Frey, Wolfgang; Dockery, Mary; Emelianov, Stanislav

    2017-06-01

    Molecular photoacoustic imaging has shown great potential in medical applications; its sensitivity is normally in pico-to-micro-molar range, dependent on exogenous imaging agents. However, tissue can produce strong background signals, which mask the signals from the imaging agents, resulting in orders of magnitude sensitivity reduction. As such, an elaborate spectral scan is often required to spectrally un-mix the unwanted background signals. Here we show a new single-wavelength photoacoustic dynamic contrast-enhanced imaging technique by employing a stimuli-responsive contrast agent. Our technique can eliminate intrinsic background noises without significant hardware or computational resources. We show that this new contrast agent can generate up to 30 times stronger photoacoustic signals than the concentration-matched inorganic nanoparticle counterparts. By dynamically modulating signals from the contrast agents with an external near-infrared optical stimulus, we can further suppress the background signals leading to an additional increase of more than five-fold in imaging contrast in vivo.

  5. Multi-stimuli responsive Cu2S nanocrystals as trimodal imaging and synergistic chemo-photothermal therapy agents

    Science.gov (United States)

    Poulose, Aby Cheruvathoor; Veeranarayanan, Srivani; Mohamed, M. Sheikh; Nagaoka, Yutaka; Romero Aburto, Rebeca; Mitcham, Trevor; Ajayan, Pulickel M.; Bouchard, Richard R.; Sakamoto, Yasushi; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D.

    2015-04-01

    A size and shape tuned, multifunctional metal chalcogenide, Cu2S-based nanotheranostic agent is developed for trimodal imaging and multimodal therapeutics against brain cancer cells. This theranostic agent was highly efficient in optical, photoacoustic and X-ray contrast imaging systems. The folate targeted NIR-responsive photothermal ablation in synergism with the chemotherapeutic action of doxorubicin proved to be a rapid precision guided cancer-killing module. The multi-stimuli, i.e., pH-, thermo- and photo-responsive drug release behavior of the nanoconjugates opens up a wider corridor for on-demand triggered drug administration. The simple synthesis protocol, combined with the multitudes of interesting features packed into a single nanoformulation, clearly demonstrates the competing role of this Cu2S nanosystem in future cancer treatment strategies.A size and shape tuned, multifunctional metal chalcogenide, Cu2S-based nanotheranostic agent is developed for trimodal imaging and multimodal therapeutics against brain cancer cells. This theranostic agent was highly efficient in optical, photoacoustic and X-ray contrast imaging systems. The folate targeted NIR-responsive photothermal ablation in synergism with the chemotherapeutic action of doxorubicin proved to be a rapid precision guided cancer-killing module. The multi-stimuli, i.e., pH-, thermo- and photo-responsive drug release behavior of the nanoconjugates opens up a wider corridor for on-demand triggered drug administration. The simple synthesis protocol, combined with the multitudes of interesting features packed into a single nanoformulation, clearly demonstrates the competing role of this Cu2S nanosystem in future cancer treatment strategies. Electronic supplementary information (ESI) available: Methodology and additional experimental results. See DOI: 10.1039/c4nr07139e

  6. High-Caloric and Chocolate Stimuli Processing in Healthy Humans: An Integration of Functional Imaging and Electrophysiological Findings

    Science.gov (United States)

    Asmaro, Deyar; Liotti, Mario

    2014-01-01

    There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) have identified neural regions and electrical signatures that are elicited by chocolate cue presentations. This review will examine fMRI and ERP findings from studies that used high-caloric food and chocolate cues as stimuli, with a focus on responses observed in samples of healthy participants, as opposed to those with eating-related pathology. The utility of using high-caloric and chocolate stimuli as a means of understanding the human reward system will also be highlighted, as these findings may be particularly important for understanding processes related to pathological overeating and addiction to illicit substances. Finally, research from our own lab that focused on chocolate stimulus processing in chocolate cravers and non-cravers will be discussed, as the approach used may help bridge fMRI and ERP findings so that a more complete understanding of appetitive stimulus processing in the temporal and spatial domains may be established. PMID:24434747

  7. High-Caloric and Chocolate Stimuli Processing in Healthy Humans: An Integration of Functional Imaging and Electrophysiological Findings

    Directory of Open Access Journals (Sweden)

    Deyar Asmaro

    2014-01-01

    Full Text Available There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI and event-related potentials (ERPs have identified neural regions and electrical signatures that are elicited by chocolate cue presentations. This review will examine fMRI and ERP findings from studies that used high-caloric food and chocolate cues as stimuli, with a focus on responses observed in samples of healthy participants, as opposed to those with eating-related pathology. The utility of using high-caloric and chocolate stimuli as a means of understanding the human reward system will also be highlighted, as these findings may be particularly important for understanding processes related to pathological overeating and addiction to illicit substances. Finally, research from our own lab that focused on chocolate stimulus processing in chocolate cravers and non-cravers will be discussed, as the approach used may help bridge fMRI and ERP findings so that a more complete understanding of appetitive stimulus processing in the temporal and spatial domains may be established.

  8. Representations of modality-specific affective processing for visual and auditory stimuli derived from functional magnetic resonance imaging data.

    Science.gov (United States)

    Shinkareva, Svetlana V; Wang, Jing; Kim, Jongwan; Facciani, Matthew J; Baucom, Laura B; Wedell, Douglas H

    2014-07-01

    There is converging evidence that people rapidly and automatically encode affective dimensions of objects, events, and environments that they encounter in the normal course of their daily routines. An important research question is whether affective representations differ with sensory modality. This research examined the nature of the dependency of affect and sensory modality at a whole-brain level of analysis in an incidental affective processing paradigm. Participants were presented with picture and sound stimuli that differed in positive or negative valence in an event-related functional magnetic resonance imaging experiment. Global statistical tests, applied at a level of the individual, demonstrated significant sensitivity to valence within modality, but not valence across modalities. Modality-general and modality-specific valence hypotheses predict distinctly different multidimensional patterns of the stimulus conditions. Examination of lower dimensional representation of the data demonstrated separable dimensions for valence processing within each modality. These results provide support for modality-specific valence processing in an incidental affective processing paradigm at a whole-brain level of analysis. Future research should further investigate how stimulus-specific emotional decoding may be mediated by the physical properties of the stimuli.

  9. High-caloric and chocolate stimuli processing in healthy humans: an integration of functional imaging and electrophysiological findings.

    Science.gov (United States)

    Asmaro, Deyar; Liotti, Mario

    2014-01-10

    There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) have identified neural regions and electrical signatures that are elicited by chocolate cue presentations. This review will examine fMRI and ERP findings from studies that used high-caloric food and chocolate cues as stimuli, with a focus on responses observed in samples of healthy participants, as opposed to those with eating-related pathology. The utility of using high-caloric and chocolate stimuli as a means of understanding the human reward system will also be highlighted, as these findings may be particularly important for understanding processes related to pathological overeating and addiction to illicit substances. Finally, research from our own lab that focused on chocolate stimulus processing in chocolate cravers and non-cravers will be discussed, as the approach used may help bridge fMRI and ERP findings so that a more complete understanding of appetitive stimulus processing in the temporal and spatial domains may be established.

  10. Multi-stimuli manipulation of antiferromagnetic domains assessed by second-harmonic imaging

    Science.gov (United States)

    Chauleau, J.-Y.; Haltz, E.; Carrétéro, C.; Fusil, S.; Viret, M.

    2017-08-01

    Among the variety of magnetic textures available in nature, antiferromagnetism is one of the most `discrete' because of the exact cancellation of its staggered internal magnetization. It is therefore very challenging to probe. However, its insensitivity to external magnetic perturbations, together with the intrinsic sub-picosecond dynamics, make it very appealing for tomorrow's information technologies. Thus, it is essential to understand the microscopic mechanisms governing antiferromagnetic domains to achieve accurate manipulation and control. Using optical second-harmonic generation, a unique and laboratory-available tool, we succeeded in imaging with sub-micrometre resolution both electric and antiferromagnetic orders in the model multiferroic BiFeO3. We show here that antiferromagnetic domains can be manipulated with low power consumption, using sub-coercive electric fields and sub-picosecond light pulses. Interestingly, we also show that antiferromagnetic and ferroelectric domains can behave independently, thus revealing that magneto-electric coupling can lead to various arrangements of the two orders.

  11. Fluorescent polymeric assemblies as stimuli-responsive vehicles for drug controlled release and cell/tissue imaging

    Science.gov (United States)

    Chang, Ying; Li, Yang; Yu, Shirong; Mao, Jie; Liu, Cheng; Li, Qi; Yuan, Conghui; He, Ning; Luo, Weiang; Dai, Lizong

    2015-01-01

    Polymer assemblies with good biocompatibility, stimuli-responsive properties and clinical imaging capability are desirable carriers for future biomedical applications. Herein, we report on the synthesis of a novel anthracenecarboxaldehyde-decorated poly(N-(4-aminophenyl) methacryl amide-oligoethyleneglycolmonomethylether methacrylate) (P(MAAPAC-MAAP-MAPEG)) copolymer, comprising fluorescent chromophore and acid-labile moiety. This copolymer can assemble into micelles in aqueous solution and shows a spherical shape with well-defined particle size and narrow particle size distribution. The pH-responsive property of the micelles has been evaluated by the change of particle size and the controlled release of guest molecules. The intrinsic fluorescence property endows the micelles with excellent cell/tissue imaging capability. Cell viability evaluation with human hepatocellular carcinoma BEL-7402 cells demonstrates that the micelles are nontoxic. The cellular uptake of the micelles indicates a time-dependent behavior. The H22-tumor bearing mice treated with the micelles clearly exhibits the tumor accumulation. These multi-functional nanocarriers may be of great interest in the application of drug delivery.

  12. Lack of correlation between the amplitudes of TRP channel-mediated responses to weak and strong stimuli in intracellular Ca(2+) imaging experiments.

    Science.gov (United States)

    Alpizar, Yeranddy A; Sanchez, Alicia; Radwan, Ahmed; Radwan, Islam; Voets, Thomas; Talavera, Karel

    2013-11-01

    It is often observed in intracellular Ca(2+) imaging experiments that the amplitudes of the Ca(2+) signals elicited by newly characterized TRP agonists do not correlate with the amplitudes of the responses evoked subsequently by a specific potent agonist. We investigated this rather controversial phenomenon by first testing whether it is inherent to the comparison of the effects of weak and strong stimuli. Using five well-characterized TRP channel agonists in commonly used heterologous expression systems we found that the correlation between the amplitudes of the Ca(2+) signals triggered by two sequentially applied stimuli is only high when both stimuli are strong. Using mathematical simulations of intracellular Ca(2+) dynamics we illustrate that the innate heterogeneity in expression and functional properties of Ca(2+) extrusion (e.g. plasma membrane Ca(2+) ATPase) and influx (TRP channels) pathways across a cellular population is a sufficient condition for low correlation between the amplitude of Ca(2+) signals elicited by weak and strong stimuli. Taken together, our data demonstrate that this phenomenon is an expected outcome of intracellular Ca(2+) imaging experiments that cannot be taken as evidence for lack of specificity of low-efficacy stimuli, or as an indicator of the need of other cellular components for channel stimulation.

  13. Processing of food, body and emotional stimuli in anorexia nervosa: a systematic review and meta-analysis of functional magnetic resonance imaging studies.

    Science.gov (United States)

    Zhu, Yikang; Hu, Xiaochen; Wang, Jijun; Chen, Jue; Guo, Qian; Li, Chunbo; Enck, Paul

    2012-11-01

    The characteristics of the cognitive processing of food, body and emotional information in patients with anorexia nervosa (AN) are debatable. We reviewed functional magnetic resonance imaging studies to assess whether there were consistent neural basis and networks in the studies to date. Searching PubMed, Ovid, Web of Science, The Cochrane Library and Google Scholar between January 1980 and May 2012, we identified 17 relevant studies. Activation likelihood estimation was used to perform a quantitative meta-analysis of functional magnetic resonance imaging studies. For both food stimuli and body stimuli, AN patients showed increased hemodynamic response in the emotion-related regions (frontal, caudate, uncus, insula and temporal) and decreased activation in the parietal region. Although no robust brain activation has been found in response to emotional stimuli, emotion-related neural networks are involved in the processing of food and body stimuli among AN. It suggests that negative emotional arousal is related to cognitive processing bias of food and body stimuli in AN.

  14. Neuroelectrical brain imaging tools for the study of the efficacy of TV advertising stimuli and their application to neuromarketing

    CERN Document Server

    Vecchiato, Giovanni; Trettel, Arianna; Babiloni, Fabio

    2013-01-01

    In this book the authors describe their original research on the potential of both standard and high-resolution electroencephalography (EEG) for analyzing brain activity in response to TV advertising. When engineering techniques, neuroscience concepts and marketing stimuli converge in one research field, known as neuromarketing, various theoretical and practical aspects need to be considered. The book introduces and discusses those aspects in detail, while showing several experiments performed by the authors during their attempts to measure both the cognitive activity and emotional involvement of the test subjects. In these experiments, the authors apply simultaneous EEG, galvanic skin response and heart rate monitoring, and show how significant variations of these variables can be associated with attention to, memorization or enjoyment of the presented stimuli. In particular, this book shows the central role of statistical analysis in recovering significant information on the scalp and cortical areas involve...

  15. Characterizing acupuncture stimuli using brain imaging with FMRI--a systematic review and meta-analysis of the literature.

    Directory of Open Access Journals (Sweden)

    Wenjing Huang

    Full Text Available BACKGROUND: The mechanisms of action underlying acupuncture, including acupuncture point specificity, are not well understood. In the previous decade, an increasing number of studies have applied fMRI to investigate brain response to acupuncture stimulation. Our aim was to provide a systematic overview of acupuncture fMRI research considering the following aspects: 1 differences between verum and sham acupuncture, 2 differences due to various methods of acupuncture manipulation, 3 differences between patients and healthy volunteers, 4 differences between different acupuncture points. METHODOLOGY/PRINCIPAL FINDINGS: We systematically searched English, Chinese, Korean and Japanese databases for literature published from the earliest available up until September 2009, without any language restrictions. We included all studies using fMRI to investigate the effect of acupuncture on the human brain (at least one group that received needle-based acupuncture. 779 papers were identified, 149 met the inclusion criteria for the descriptive analysis, and 34 were eligible for the meta-analyses. From a descriptive perspective, multiple studies reported that acupuncture modulates activity within specific brain areas, including somatosensory cortices, limbic system, basal ganglia, brain stem, and cerebellum. Meta-analyses for verum acupuncture stimuli confirmed brain activity within many of the regions mentioned above. Differences between verum and sham acupuncture were noted in brain response in middle cingulate, while some heterogeneity was noted for other regions depending on how such meta-analyses were performed, such as sensorimotor cortices, limbic regions, and cerebellum. CONCLUSIONS: Brain response to acupuncture stimuli encompasses a broad network of regions consistent with not just somatosensory, but also affective and cognitive processing. While the results were heterogeneous, from a descriptive perspective most studies suggest that acupuncture can

  16. Cortical activation elicited by unrecognized stimuli

    Directory of Open Access Journals (Sweden)

    Badgaiyan Rajendra D

    2006-05-01

    Full Text Available Abstract Background It is unclear whether a stimulus that cannot be recognized consciously, could elicit a well-processed cognitive response. Methods We used functional imaging to examine the pattern of cortical activation elicited by unrecognized stimuli during memory processing. Subjects were given a recognition task using recognizable and non-recognizable subliminal stimuli. Results Unrecognized stimuli activated the cortical areas that are associated with retrieval attempt (left prefrontal, and novelty detection (left hippocampus. This indicates that the stimuli that were not consciously recognized, activated neural network associated with aspects of explicit memory processing. Conclusion Results suggest that conscious recognition of stimuli is not necessary for activation of cognitive processing.

  17. High-Caloric and Chocolate Stimuli Processing in Healthy Humans: An Integration of Functional Imaging and Electrophysiological Findings

    OpenAIRE

    Deyar Asmaro; Mario Liotti

    2014-01-01

    There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) have identified neural regions and electr...

  18. Stimuli-responsive magnetic nanoparticles for tumor-targeted bimodal imaging and photodynamic/hyperthermia combination therapy

    Science.gov (United States)

    Kim, Kyoung Sub; Kim, Jiyoung; Lee, Joo Young; Matsuda, Shofu; Hideshima, Sho; Mori, Yasurou; Osaka, Tetsuya; Na, Kun

    2016-06-01

    Despite magnetic nanoparticles having shown great potential in cancer treatment, tremendous challenges related to diagnostic sensitivity and treatment efficacy for clinical application remain. Herein, we designed optimized multifunctional magnetite nanoparticles (AHP@MNPs), composed of Fe3O4 nanoparticles and photosensitizer conjugated hyaluronic acid (AHP), to achieve enhanced tumor diagnosis and therapy. Fe3O4 nanoparticles (MNPs) were synthesized by a facile hydrolysis method. MNPs have higher biocompatibility, controllable particle sizes, and desirable magnetic properties. The fabricated AHP@MNPs have enhanced water solubility (average size: 108.13 +/- 1.08 nm), heat generation properties, and singlet oxygen generation properties upon magnetic and laser irradiation. The AHP@MNPs can target tumors via CD44 receptor-mediated endocytosis, which have enhanced tumor therapeutic effects through photodynamic/hyperthermia-combined treatment without any drugs. We successfully detected tumors implanted in mice via magnetic resonance imaging and optical imaging. Furthermore, we demonstrated the photodynamic/hyperthermia-combined therapeutic efficacy of AHP@MNPs with synergistically enhanced efficacy against cancer.Despite magnetic nanoparticles having shown great potential in cancer treatment, tremendous challenges related to diagnostic sensitivity and treatment efficacy for clinical application remain. Herein, we designed optimized multifunctional magnetite nanoparticles (AHP@MNPs), composed of Fe3O4 nanoparticles and photosensitizer conjugated hyaluronic acid (AHP), to achieve enhanced tumor diagnosis and therapy. Fe3O4 nanoparticles (MNPs) were synthesized by a facile hydrolysis method. MNPs have higher biocompatibility, controllable particle sizes, and desirable magnetic properties. The fabricated AHP@MNPs have enhanced water solubility (average size: 108.13 +/- 1.08 nm), heat generation properties, and singlet oxygen generation properties upon magnetic and laser

  19. Auditory scene analysis and sonified visual images. Does consonance negatively impact on object formation when using complex sonified stimuli?

    Science.gov (United States)

    Brown, David J; Simpson, Andrew J R; Proulx, Michael J

    2015-01-01

    A critical task for the brain is the sensory representation and identification of perceptual objects in the world. When the visual sense is impaired, hearing and touch must take primary roles and in recent times compensatory techniques have been developed that employ the tactile or auditory system as a substitute for the visual system. Visual-to-auditory sonifications provide a complex, feature-based auditory representation that must be decoded and integrated into an object-based representation by the listener. However, we don't yet know what role the auditory system plays in the object integration stage and whether the principles of auditory scene analysis apply. Here we used coarse sonified images in a two-tone discrimination task to test whether auditory feature-based representations of visual objects would be confounded when their features conflicted with the principles of auditory consonance. We found that listeners (N = 36) performed worse in an object recognition task when the auditory feature-based representation was harmonically consonant. We also found that this conflict was not negated with the provision of congruent audio-visual information. The findings suggest that early auditory processes of harmonic grouping dominate the object formation process and that the complexity of the signal, and additional sensory information have limited effect on this.

  20. Auditory Scene Analysis and sonified visual images. Does consonance negatively impact on object formation when using complex sonified stimuli?

    Directory of Open Access Journals (Sweden)

    David J Brown

    2015-10-01

    Full Text Available A critical task for the brain is the sensory representation and identification of perceptual objects in the world. When the visual sense is impaired, hearing and touch must take primary roles and in recent times compensatory techniques have been developed that employ the tactile or auditory system as a substitute for the visual system. Visual-to-auditory sonifications provide a complex, feature-based auditory representation that must be decoded and integrated into an object-based representation by the listener. However, we don’t yet know what role the auditory system plays in the object integration stage and whether the principles of auditory scene analysis apply. Here we used coarse sonified images in a two-tone discrimination task to test whether auditory feature-based representations of visual objects would be confounded when their features conflicted with the principles of auditory consonance. We found that listeners (N = 36 performed worse in an object recognition task when the auditory feature-based representation was harmonically consonant. We also found that this conflict was not negated with the provision of congruent audio-visual information. The findings suggest that early auditory processes of harmonic grouping dominate the object formation process and that the complexity of the signal, and additional sensory information have limited effect on this.

  1. Stimuli-Responsive Biodegradable Hyperbranched Polymer-Gadolinium Conjugates as Efficient and Biocompatible Nanoscale Magnetic Resonance Imaging Contrast Agents.

    Science.gov (United States)

    Sun, Ling; Li, Xue; Wei, Xiaoli; Luo, Qiang; Guan, Pujun; Wu, Min; Zhu, Hongyan; Luo, Kui; Gong, Qiyong

    2016-04-27

    The efficacy and biocompatibility of nanoscale magnetic resonance imaging (MRI) contrast agents depend on optimal molecular structures and compositions. Gadolinium [Gd(III)] based dendritic macromolecules with well-defined and tunable nanoscale sizes are excellent candidates as multivalent MRI contrast agents. Here, we propose a novel alternate preparation of biodegradable hyperbranched polymer-gadolinium conjugates via a simple strategy and report potentially efficient and biocompatible nanoscale MRI contrast agents for cancer diagnosis. The enzyme-responsive hyperbranched poly(oligo-(ethylene glycol) methacrylate)-gadolinium conjugate (HB-POEGMA-Gd) was prepared via one-step reversible addition-fragmentation chain transfer (RAFT) polymerization and Gd(III) chelating, and the cRGDyK functionalized polymer (HB-POEGMA-cRGD-Gd) was obtained via click chemistry. By using an enzyme similar to lysosomal cathepsin B, hyperbranched conjugates of high molecular weights (MW) (180 and 210 kDa) and nanoscale sizes (38 and 42 nm) were degraded into low MW (25 and 30 kDa) and smaller products (4.8 and 5.2 nm) below the renal threshold. Conjugate-based nanoscale systems had three-fold more T1 relaxivity compared to clinical agent diethylenediaminepentaacetic acid (DTPA)-Gd. Animal studies with the nanoscale system offered greater tumor accumulation and enhanced signal intensity (SI) in mouse U87 tumors of which the greatest activity was conferred by the cRGDyK moiety functionalized hyperbranched conjugate. In vitro cytotoxicity, hemocompatibility and in vivo toxicity studies confirmed no adverse events. This design strategy for multifunctional Gd(III)-labeled biodegradable dendritic macromolecules may have significant potential as future efficient, biocompatible polymeric nanoscale MRI diagnostic contrast agents for cancer.

  2. Ball-in-ball ZrO2 nanostructure for simultaneous CT imaging and highly efficient synergic microwave ablation and tri-stimuli-responsive chemotherapy of tumors.

    Science.gov (United States)

    Long, Dan; Niu, Meng; Tan, Longfei; Fu, Changhui; Ren, Xiangling; Xu, Ke; Zhong, Hongshan; Wang, Jingzhuo; Li, Laifeng; Meng, Xianwei

    2017-06-29

    Combined thermo-chemotherapy displays outstanding synergically therapeutic efficiency when compared with standalone thermotherapy and chemotherapy. Herein, we developed a smart tri-stimuli-responsive drug delivery system involving X@BB-ZrO2 NPs (X represents loaded IL, DOX, keratin and tetradecanol) based on novel ball-in-ball-structured ZrO2 nanoparticles (BB-ZrO2 NPs). The microwave energy conversion efficiency of BB-ZrO2 NPs was 41.2% higher than that of traditional single-layer NPs due to the cooperative action of self-reflection and spatial confinement effect of the special two-layer hollow nanostructure. The tri-stimuli-responsive controlled release strategy indicate that integrated pH, redox and microwaves in single NPs based on keratin and tetradecanol could effectively enhance the specific controlled release of DOX. The release of DOX was only 8.1% in PBS with pH = 7.2 and GSH = 20 μM. However, the release could reach about 50% at the tumor site (pH = 5.5, GSH = 13 mM) under microwave ablation. The as-made X@BB-ZrO2 NPs exhibited perfect synergic therapy effect of chemotherapy and microwave ablation both in subcutaneous tumors (H22 tumor-bearing mice) and deep tumors (liver transplantation VX2 tumor-bearing rabbit model). There was no recurrence and death in the X@BB-ZrO2 + MW group during the therapy of subcutaneous tumors even on the 42(nd) day. The growth rates in the deep tumor of the control, MW and X@BB-ZrO2 + MW groups were 290.1%, 14.1% and -42% 6 days after ablation, respectively. Dual-source CT was used to monitor the metabolism behavior of the as-made BB-ZrO2 NPs and traditional CT was utilized to monitor the tumor growth in rabbits. Frozen section examination and ICP results indicated the precise control of drug delivery and enhanced cytotoxicity by the tri-stimuli-responsive controlled release strategy. The ball-in-ball ZrO2 NPs with high microwave energy conversion efficiency were first developed for synergic microwave ablation and tri-stimuli

  3. VEP Responses to Op-Art Stimuli.

    Directory of Open Access Journals (Sweden)

    Louise O'Hare

    Full Text Available Several types of striped patterns have been reported to cause adverse sensations described as visual discomfort. Previous research using op-art-based stimuli has demonstrated that spurious eye movement signals can cause the experience of illusory motion, or shimmering effects, which might be perceived as uncomfortable. Whilst the shimmering effects are one cause of discomfort, another possible contributor to discomfort is excessive neural responses: As striped patterns do not have the statistical redundancy typical of natural images, they are perhaps unable to be encoded efficiently. If this is the case, then this should be seen in the amplitude of the EEG response. This study found that stimuli that were judged to be most comfortable were also those with the lowest EEG amplitude. This provides some support for the idea that excessive neural responses might also contribute to discomfort judgements in normal populations, in stimuli controlled for perceived contrast.

  4. VEP Responses to Op-Art Stimuli.

    Science.gov (United States)

    O'Hare, Louise; Clarke, Alasdair D F; Pollux, Petra M J

    2015-01-01

    Several types of striped patterns have been reported to cause adverse sensations described as visual discomfort. Previous research using op-art-based stimuli has demonstrated that spurious eye movement signals can cause the experience of illusory motion, or shimmering effects, which might be perceived as uncomfortable. Whilst the shimmering effects are one cause of discomfort, another possible contributor to discomfort is excessive neural responses: As striped patterns do not have the statistical redundancy typical of natural images, they are perhaps unable to be encoded efficiently. If this is the case, then this should be seen in the amplitude of the EEG response. This study found that stimuli that were judged to be most comfortable were also those with the lowest EEG amplitude. This provides some support for the idea that excessive neural responses might also contribute to discomfort judgements in normal populations, in stimuli controlled for perceived contrast.

  5. Individual perception of different stimuli: Implications for managers

    Directory of Open Access Journals (Sweden)

    Santos- Álvarez, M.V.

    2012-01-01

    Full Text Available Managerial perception is the process by which managers form an image of the stimuli they receive. According to research, perception is conditioned by the individual’s cognitive profile. But the different nature of incoming stimuli suggests that it would be interesting to study whether the cognitive profile’s influence varies in the presence of different stimuli. This paper analyses the effect of the cognitive profile on perception of differently-structured stimuli. The results clearly show that the cognitive style, tolerance of ambiguity, and proactivity have an effect. Specifically, they condition the recognition of stimuli, particularly when the stimuli are relatively unstructured. The results also show that the cognitive variables have less influence in the interpretation stage.

  6. Emotional stimuli and motor conversion disorder

    NARCIS (Netherlands)

    Voon, V.; Brezing, C.; Gallea, C.; Ameli, R.; Roelofs, K.; LaFrance, W.C.; Hallett, M.

    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,

  7. Meet the Fribbles: Novel stimuli for use within behavioural research

    Directory of Open Access Journals (Sweden)

    Tom Joseph Barry

    2014-02-01

    Full Text Available Clinical researchers make use of experimental models for mental disorders. In many cases, these models use stimuli that are relevant to the disorder under scrutiny, which allows one to experimentally investigate the factors that contribute to the development of the disorder. For example, one might use spiders or spider-like stimuli in the study of specific phobia. More broadly, researchers often make use of real-world stimuli such as images of animals, geometrical shapes or emotional words. However, these stimuli are often limited in their experimental controllability and their applicability to the disorder in question. We present a novel set of animal-like stimuli, called Fribbles, for use within behavioural research. Fribbles have desirable properties for use in research because they are similar to real-world stimuli, but due to their novelty, participants will not have had previous experience with them. They also have known properties that can be experimentally manipulated. We present an investigation into similarity between Fribbles in order to illustrate their utility in research that relies on comparisons between similar stimuli. Fribbles offer both experimental control and generalisability to the real world, although some consideration must be made concerning the properties that influence similarity between Fribbles when selecting them along a dimension of similarity.

  8. Emotion Recognition in Animated Compared to Human Stimuli in Adolescents with Autism Spectrum Disorder

    Science.gov (United States)

    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…

  9. Consistency of Border-Ownership Cells across Artificial Stimuli, Natural Stimuli, and Stimuli with Ambiguous Contours.

    Science.gov (United States)

    Hesse, Janis K; Tsao, Doris Y

    2016-11-02

    Segmentation and recognition of objects in a visual scene are two problems that are hard to solve separately from each other. When segmenting an ambiguous scene, it is helpful to already know the present objects and their shapes. However, for recognizing an object in clutter, one would like to consider its isolated segment alone to avoid confounds from features of other objects. Border-ownership cells (Zhou et al., 2000) appear to play an important role in segmentation, as they signal the side-of-figure of artificial stimuli. The present work explores the role of border-ownership cells in dorsal macaque visual areas V2 and V3 in the segmentation of natural object stimuli and locally ambiguous stimuli. We report two major results. First, compared with previous estimates, we found a smaller percentage of cells that were consistent across artificial stimuli used previously. Second, we found that the average response of those neurons that did respond consistently to the side-of-figure of artificial stimuli also consistently signaled, as a population, the side-of-figure for borders of single faces, occluding faces and, with higher latencies, even stimuli with illusory contours, such as Mooney faces and natural faces completely missing local edge information. In contrast, the local edge or the outlines of the face alone could not always evoke a significant border-ownership signal. Our results underscore that border ownership is coded by a population of cells, and indicate that these cells integrate a variety of cues, including low-level features and global object context, to compute the segmentation of the scene.

  10. Stimuli, Reinforcers, and Private Events

    Science.gov (United States)

    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…

  11. Stimuli, Reinforcers, and Private Events

    Science.gov (United States)

    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…

  12. Emotional Stimuli and Motor Conversion Disorder

    Science.gov (United States)

    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…

  13. Subconscious Subliminal Stimuli And rrrsssssshhhppp!

    DEFF Research Database (Denmark)

    Lewis Brooks, Anthony

    2003-01-01

    in a ‘remarkable reductive retraction’ from ‘fixation centers’ such that a more human intuitive interaction to the ‘New World’ becomes apparent in design scenarios. Ubiquitous ‘Virtual Interactive Space’ (Brooks, 1999) will become a more utilized and higher resolution capture resource integrative to design...... of such issues as outlined in my opening statement. I suggest that successful design of the future will take much more into account the neural stimuli & potential subliminal synesthesia design aspects as an integrated element of the envisioned Virtual Interactive Space. Keywords: remarkable reductive retraction...

  14. Generating stimuli for neuroscience using PsychoPy

    Directory of Open Access Journals (Sweden)

    Jonathan W Peirce

    2009-01-01

    Full Text Available PsychoPy is a software library written in Python, using OpenGL to generate very precise visual stimuli on standard personal computers. It is designed to allow the construction of as wide a variety of neuroscience experiments as possible, with the least effort. By writing scripts in standard Python syntax users can generate an enormous variety of visual and auditory stimuli and can interact with a wide range of external hardware (enabling its use in fMRI, EEG, MEG etc.. The structure of scripts is simple and intuitive. As a result, new experiments can be written very quickly, and trying to understand a previously written script is easy, even with minimal code comments. PsychoPy can also generate movies and image sequences to be used in demos or simulated neuroscience experiments. This paper describes the range of tools and stimuli that it provides and the environment in which experiments are conducted.

  15. Generating Stimuli for Neuroscience Using PsychoPy.

    Science.gov (United States)

    Peirce, Jonathan W

    2008-01-01

    PsychoPy is a software library written in Python, using OpenGL to generate very precise visual stimuli on standard personal computers. It is designed to allow the construction of as wide a variety of neuroscience experiments as possible, with the least effort. By writing scripts in standard Python syntax users can generate an enormous variety of visual and auditory stimuli and can interact with a wide range of external hardware (enabling its use in fMRI, EEG, MEG etc.). The structure of scripts is simple and intuitive. As a result, new experiments can be written very quickly, and trying to understand a previously written script is easy, even with minimal code comments. PsychoPy can also generate movies and image sequences to be used in demos or simulated neuroscience experiments. This paper describes the range of tools and stimuli that it provides and the environment in which experiments are conducted.

  16. Exploring the Development and Dismantling of Equivalence Classes Involving Terrorist Stimuli

    Science.gov (United States)

    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,…

  17. Vestibular rehabilitation with visual stimuli in peripheral vestibular disorders

    Directory of Open Access Journals (Sweden)

    Andréa Manso

    2016-04-01

    Full Text Available ABSTRACT INTRODUCTION: Visual stimuli can induce vestibular adaptation and recovery of body balance. OBJECTIVE: To verify the effect of visual stimuli by digital images on vestibular and body balance rehabilitation of peripheral vestibular disorders. METHODS: Clinical, randomized, prospective study. Forty patients aged between 23 and 63 years with chronic peripheral vestibular disorders underwent 12 sessions of rehabilitation with visual stimuli using digital video disk (DVD (experimental group or Cawthorne-Cooksey exercises (control group. The Dizziness Handicap Inventory (DHI, dizziness analog scale, and the sensitized Romberg static balance and one-leg stance tests were applied before and after the intervention. RESULTS: Before and after the intervention, there was no difference between the experimental and control groups (p > 0.005 regarding the findings of DHI, dizziness analog scale, and static balance tests. After the intervention, the experimental and control groups showed lower values (p < 0.05 in the DHI and the dizziness analog scale, and higher values (p < 0.05 in the static balance tests in some of the assessed conditions. CONCLUSION: The inclusion of visual stimuli by digital images on vestibular and body balance rehabilitation is effective in reducing dizziness and improving quality of life and postural control in individuals with peripheral vestibular disorders.

  18. Visual and auditory stimuli associated with swallowing activate mirror neurons: a magnetoencephalography study.

    Science.gov (United States)

    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.

  19. Conscious perception of emotional stimuli: brain mechanisms.

    Science.gov (United States)

    Mitchell, Derek G V; Greening, Steven G

    2012-08-01

    Emotional stimuli are thought to gain rapid and privileged access to processing resources in the brain. The structures involved in this enhanced access are thought to support subconscious, reflexive processes. Whether these pathways contribute to the phenomenological experience of emotional visual awareness (i.e., conscious perception) is unclear. In this review, it is argued that subcortical networks associated with the rapid detection of emotionally salient stimuli also play a key role in shaping awareness. This proposal is based on the idea that awareness of visual stimuli should be considered along a continuum, having intermediate levels, rather than as an all-or-none construct. It is also argued that awareness of emotional stimuli requires less input from frontoparietal structures that are often considered crucial for visual awareness. Evidence is also presented that implicates a region of the medial prefrontal cortex, involved in emotion regulation, in modulating amygdala output to determine awareness of emotional visual stimuli; when emotional stimuli are present, the conscious perception of alternative stimuli requires greater regulatory influences from cortical structures. Thus, emotional stimuli are privileged not only for neuronal representation and impact on subconscious processes, but also for awareness, allowing humans to deal flexibly rather than merely reflexively to biologically significant stimuli.

  20. Temporal sensitivity. [time dependent human perception of visual stimuli

    Science.gov (United States)

    Watson, Andrew B.

    1986-01-01

    Human visual temporal sensitivity is examined. The stimuli used to measure temporal sensitivity are described and the linear systems theory is reviewed in terms of temporal sensitivity. A working model which represents temporal sensitivity is proposed. The visibility of a number of temporal wave forms, sinusoids, rectangular pulses, and pulse pairs, is analyzed. The relation between spatial and temporal effects is studied. Temporal variations induced by image motion and the effects of light adaptation on temporal sensitivity are considered.

  1. Cardiorespiratory interactions to external stimuli.

    Science.gov (United States)

    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.

  2. Cognitive control modulates preferential sensory processing of affective stimuli.

    Science.gov (United States)

    Steinhauser, Marco; Flaisch, Tobias; Meinzer, Marcus; Schupp, Harald T

    2016-10-01

    Adaptive human behavior crucially relies on the ability of the brain to allocate resources automatically to emotionally significant stimuli. This ability has consistently been demonstrated by studies showing preferential processing of affective stimuli in sensory cortical areas. It is still unclear, however, whether this putatively automatic mechanism can be modulated by cognitive control processes. Here, we use functional magnetic resonance imaging (fMRI) to investigate whether preferential processing of an affective face distractor is suppressed when an affective distractor has previously elicited a response conflict in a word-face Stroop task. We analyzed this for three consecutive stages in the ventral stream of visual processing for which preferential processing of affective stimuli has previously been demonstrated: the striate area (BA 17), category-unspecific extrastriate areas (BA 18/19), and the fusiform face area (FFA). We found that response conflict led to a selective suppression of affective face processing in category-unspecific extrastriate areas and the FFA, and this effect was accompanied by changes in functional connectivity between these areas and the rostral anterior cingulate cortex. In contrast, preferential processing of affective face distractors was unaffected in the striate area. Our results indicate that cognitive control processes adaptively suppress preferential processing of affective stimuli under conditions where affective processing is detrimental because it elicits response conflict.

  3. Fear conditioning to subliminal fear relevant and non fear relevant stimuli.

    Directory of Open Access Journals (Sweden)

    Ottmar V Lipp

    Full Text Available A growing body of evidence suggests that conscious visual awareness is not a prerequisite for human fear learning. For instance, humans can learn to be fearful of subliminal fear relevant images--images depicting stimuli thought to have been fear relevant in our evolutionary context, such as snakes, spiders, and angry human faces. Such stimuli could have a privileged status in relation to manipulations used to suppress usually salient images from awareness, possibly due to the existence of a designated sub-cortical 'fear module'. Here we assess this proposition, and find it wanting. We use binocular masking to suppress awareness of images of snakes and wallabies (particularly cute, non-threatening marsupials. We find that subliminal presentations of both classes of image can induce differential fear conditioning. These data show that learning, as indexed by fear conditioning, is neither contingent on conscious visual awareness nor on subliminal conditional stimuli being fear relevant.

  4. Social attention with real versus reel stimuli: toward an empirical approach to concerns about ecological validity

    Science.gov (United States)

    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

  5. Agnosia for Mirror Stimuli: A New Case Report with a Small Parietal Lesion

    Science.gov (United States)

    Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Lebas, Axel; Gerardin, Emmanuel; Hannequin, Didier

    2014-01-01

    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. PMID:25037846

  6. Social attention with real versus reel stimuli: toward an empirical approach to concerns about ecological validity.

    Science.gov (United States)

    Risko, Evan F; Laidlaw, Kaitlin; 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.

  7. Effective stimuli for constructing reliable neuron models.

    Directory of Open Access Journals (Sweden)

    Shaul Druckmann

    2011-08-01

    Full Text Available 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.

  8. Modeling auditory evoked potentials to complex stimuli

    DEFF Research Database (Denmark)

    Rønne, Filip Munch

    The auditory evoked potential (AEP) is an electrical signal that can be recorded from electrodes attached to the scalp of a human subject when a sound is presented. The signal is considered to reflect neural activity in response to the acoustic stimulation and is a well established clinical...... clinically and in research towards using realistic and complex stimuli, such as speech, to electrophysiologically assess the human hearing. However, to interpret the AEP generation to complex sounds, the potential patterns in response to simple stimuli needs to be understood. Therefore, the model was used...... to simulate auditory brainstem responses (ABRs) evoked by classic stimuli like clicks, tone bursts and chirps. The ABRs to these simple stimuli were compared to literature data and the model was shown to predict the frequency dependence of tone-burst ABR wave-V latency and the level-dependence of ABR wave...

  9. Modeling Stimuli-Responsive Nanoparticle Monolayer

    Science.gov (United States)

    Yong, Xin

    2015-03-01

    Using dissipative particle dynamics (DPD), we model a monolayer formed at the water-oil interface, which comprises stimuli-responsive nanoparticles. The solid core of the nanoparticle encompasses beads arranged in an fcc lattice structure and its surface is uniformly grafted with stimuli-responsive polymer chains. The surface-active nanoparticles adsorb to the interface from the suspension to minimize total energy of the system and create a monolayer covering the interface. We investigate the monolayer formation by characterizing the detailed adsorption kinetics. We explore the microstructure of the monolayer at different surface coverage, including the particle crowding and ordering, and elucidate the response of monolayer to external stimuli. The collective behavior of the particles within the monolayer is demonstrated quantitatively by vector-vector autocorrelation functions. This study provides a fundamental understanding of the interfacial behavior of stimuli-responsive nanoparticles.

  10. Preparing to grasp emotionally laden stimuli.

    Directory of Open Access Journals (Sweden)

    Laura Alice Santos de Oliveira

    Full Text Available BACKGROUND: Contemporary theories of motor control propose that motor planning involves the prediction of the consequences of actions. These predictions include the associated costs as well as the rewarding nature of movements' outcomes. Within the estimation of these costs and rewards would lie the valence, that is, the pleasantness or unpleasantness of a given stimulus with which one is about to interact. The aim of this study was to test if motor preparation encompasses valence. METHODOLOGY/PRINCIPAL FINDINGS: The readiness potential, an electrophysiological marker of motor preparation, was recorded before the grasping of pleasant, neutral and unpleasant stimuli. Items used were balanced in weight and placed inside transparent cylinders to prompt a similar grip among trials. Compared with neutral stimuli, the grasping of pleasant stimuli was preceded by a readiness potential of lower amplitude, whereas that of unpleasant stimuli was associated with a readiness potential of higher amplitude. CONCLUSIONS/SIGNIFICANCE: We show for the first time that the sensorimotor cortex activity preceding the grasping of a stimulus is affected by its valence. Smaller readiness potential amplitudes found for pleasant stimuli could imply in the recruitment of pre-set motor repertoires, whereas higher amplitudes found for unpleasant stimuli would emerge from a discrepancy between the required action and their aversiveness. Our results indicate that the prediction of action outcomes encompasses an estimate of the valence of a stimulus with which one is about to interact.

  11. Preparing to Grasp Emotionally Laden Stimuli

    Science.gov (United States)

    de Oliveira, Laura Alice Santos; Imbiriba, Luís Aureliano; Russo, Maitê Mello; Nogueira-Campos, Anaelli A.; Rodrigues, Erika de C.; Pereira, Mirtes G.; Volchan, Eliane; Vargas, Cláudia Domingues

    2012-01-01

    Background Contemporary theories of motor control propose that motor planning involves the prediction of the consequences of actions. These predictions include the associated costs as well as the rewarding nature of movements’ outcomes. Within the estimation of these costs and rewards would lie the valence, that is, the pleasantness or unpleasantness of a given stimulus with which one is about to interact. The aim of this study was to test if motor preparation encompasses valence. Methodology/Principal Findings The readiness potential, an electrophysiological marker of motor preparation, was recorded before the grasping of pleasant, neutral and unpleasant stimuli. Items used were balanced in weight and placed inside transparent cylinders to prompt a similar grip among trials. Compared with neutral stimuli, the grasping of pleasant stimuli was preceded by a readiness potential of lower amplitude, whereas that of unpleasant stimuli was associated with a readiness potential of higher amplitude. Conclusions/Significance We show for the first time that the sensorimotor cortex activity preceding the grasping of a stimulus is affected by its valence. Smaller readiness potential amplitudes found for pleasant stimuli could imply in the recruitment of pre-set motor repertoires, whereas higher amplitudes found for unpleasant stimuli would emerge from a discrepancy between the required action and their aversiveness. Our results indicate that the prediction of action outcomes encompasses an estimate of the valence of a stimulus with which one is about to interact. PMID:23024811

  12. Cognitive biases to appearance-related stimuli in body dissatisfaction: A systematic review.

    Science.gov (United States)

    Rodgers, Rachel F; DuBois, Russell H

    2016-06-01

    Emerging literature has documented the presence of cognitive biases toward body image related stimuli among individuals with high levels of body image concerns compared to those with low levels of body image concerns. However, the robustness and nature of these cognitive biases are unclear. The aims of this study were to conduct a systematic literature search and perform a critical synthesis of studies examining the relationship between cognitive biases toward body image-related stimuli and body image concerns. Our review identified 32 studies meeting inclusion criteria. Dot-probe, Stroop, free recall, and eye-tracking were among the most frequently used paradigms. The extant literature provides robust support for the presence of attention biases toward body image-related stimuli among individuals with high levels of body dissatisfaction compared to those with lower levels of concerns. Evidence was also found for the existence of judgment biases and memory biases. Furthermore, results suggest that body image-related cognitive biases, and levels of body dissatisfaction can be manipulated. Initial evidence was also found for differential patterns of biases toward "fat" and "thin" stimuli. These findings confirm the importance of considering cognitive biases within etiological models of body image concerns and suggest that these processes might provide novel treatment targets.

  13. The N170 component is sensitive to face-like stimuli: a study of Chinese Peking opera makeup.

    Science.gov (United States)

    Liu, Tiantian; Mu, Shoukuan; He, Huamin; Zhang, Lingcong; Fan, Cong; Ren, Jie; Zhang, Mingming; He, Weiqi; Luo, Wenbo

    2016-12-01

    The N170 component is considered a neural marker of face-sensitive processing. In the present study, the face-sensitive N170 component of event-related potentials (ERPs) was investigated with a modified oddball paradigm using a natural face (the standard stimulus), human- and animal-like makeup stimuli, scrambled control images that mixed human- and animal-like makeup pieces, and a grey control image. Nineteen participants were instructed to respond within 1000 ms by pressing the 'F' or 'J' key in response to the standard or deviant stimuli, respectively. We simultaneously recorded ERPs, response accuracy, and reaction times. The behavioral results showed that the main effect of stimulus type was significant for reaction time, whereas there were no significant differences in response accuracies among stimulus types. In relation to the ERPs, N170 amplitudes elicited by human-like makeup stimuli, animal-like makeup stimuli, scrambled control images, and a grey control image progressively decreased. A right hemisphere advantage was observed in the N170 amplitudes for human-like makeup stimuli, animal-like makeup stimuli, and scrambled control images but not for grey control image. These results indicate that the N170 component is sensitive to face-like stimuli and reflect configural processing in face recognition.

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

    Science.gov (United States)

    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.

  15. Generalization of the disruptive effects of alternative stimuli when combined with target stimuli in extinction.

    Science.gov (United States)

    Podlesnik, Christopher A; Miranda-Dukoski, Ludmila; Jonas Chan, C K; Bland, Vikki J; Bai, John Y H

    2017-09-01

    Differential-reinforcement treatments reduce target problem behavior in the short term but at the expense of making it more persistent long term. Basic and translational research based on behavioral momentum theory suggests that combining features of stimuli governing an alternative response with the stimuli governing target responding could make target responding less persistent. However, changes to the alternative stimulus context when combining alternative and target stimuli could diminish the effectiveness of the alternative stimulus in reducing target responding. In an animal model with pigeons, the present study reinforced responding in the presence of target and alternative stimuli. When combining the alternative and target stimuli during extinction, we altered the alternative stimulus through changes in line orientation. We found that (1) combining alternative and target stimuli in extinction more effectively decreased target responding than presenting the target stimulus on its own; (2) combining these stimuli was more effective in decreasing target responding trained with lower reinforcement rates; and (3) changing the alternative stimulus reduced its effectiveness when it was combined with the target stimulus. Therefore, changing alternative stimuli (e.g., therapist, clinical setting) during behavioral treatments that combine alternative and target stimuli could reduce the effectiveness of those treatments in disrupting problem behavior. © 2017 Society for the Experimental Analysis of Behavior.

  16. Stimuli-responsive smart gating membranes.

    Science.gov (United States)

    Liu, Zhuang; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Chu, Liang-Yin

    2016-02-07

    Membranes are playing paramount roles in the sustainable development of myriad fields such as energy, environmental and resource management, and human health. However, the unalterable pore size and surface properties of traditional porous membranes restrict their efficient applications. The performances of traditional membranes will be weakened upon unavoidable membrane fouling, and they cannot be applied to cases where self-regulated permeability and selectivity are required. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-responsive smart gating membranes are developed by chemically/physically incorporating stimuli-responsive materials as functional gates into traditional porous membranes, to provide advanced functions and enhanced performances for breaking the bottlenecks of traditional membrane technologies. Smart gating membranes, integrating the advantages of traditional porous membrane substrates and smart functional gates, can self-regulate their permeability and selectivity via the flexible adjustment of pore sizes and surface properties based on the "open/close" switch of the smart gates in response to environmental stimuli. This tutorial review summarizes the recent developments in stimuli-responsive smart gating membranes, including the design strategies and the fabrication strategies that are based on the introduction of the stimuli-responsive gates after or during membrane formation, and the positively and negatively responsive gating models of versatile stimuli-responsive smart gating membranes, as well as the advanced applications of smart gating membranes for regulating substance concentration in reactors, controlling the release rate of drugs, separating active molecules based on size or affinity, and the self-cleaning of membrane surfaces. With self-regulated membrane performances, smart gating membranes show great power for use in global sustainable development.

  17. Perceptual memory drives learning of retinotopic biases for bistable stimuli.

    Directory of Open Access Journals (Sweden)

    Aidan Peter Murphy

    2014-02-01

    Full Text Available The visual system exploits past experience at multiple timescales to resolve perceptual ambiguity in the retinal image. For example, perception of a bistable stimulus can be biased towards one interpretation over another when preceded by a brief presentation of a disambiguated version of the stimulus (positive priming or through intermittent presentations of the ambiguous stimulus (stabilization. Similarly, prior presentations of unambiguous stimuli can be used to explicitly train a long-lasting association between a percept and a retinal location (perceptual association. These phenonema have typically been regarded as independent processes, with short-term biases attributed to perceptual memory and longer-term biases described as associative learning. Here we tested for interactions between these two forms of experience-dependent perceptual bias and demonstrate that short-term processes strongly influence long-term outcomes. We first demonstrate that the establishment of long-term perceptual contingencies does not require explicit training by unambiguous stimuli, but can arise spontaneously during the periodic presentation of brief, ambiguous stimuli. Using rotating Necker cube stimuli, we observed enduring, retinotopically specific perceptual biases that were expressed from the outset and remained stable for up to forty minutes, consistent with the known phenomenon of perceptual stabilization. Further, bias was undiminished after a break period of five minutes, but was readily reset by interposed periods of continuous, as opposed to periodic, ambiguous presentation. Taken together, the results demonstrate that perceptual biases can arise naturally and may principally reflect the brain’s tendency to favor recent perceptual interpretation at a given retinal location. Further, they suggest that an association between retinal location and perceptual state, rather than a physical stimulus, is sufficient to generate long-term biases in perceptual

  18. Neural activation toward erotic stimuli in homosexual and heterosexual males.

    Science.gov (United States)

    Kagerer, Sabine; Klucken, Tim; Wehrum, Sina; Zimmermann, Mark; Schienle, Anne; Walter, Bertram; Vaitl, Dieter; Stark, Rudolf

    2011-11-01

    Studies investigating sexual arousal exist, yet there are diverging findings on the underlying neural mechanisms with regard to sexual orientation. Moreover, sexual arousal effects have often been confounded with general arousal effects. Hence, it is still unclear which structures underlie the sexual arousal response in homosexual and heterosexual men. Neural activity and subjective responses were investigated in order to disentangle sexual from general arousal. Considering sexual orientation, differential and conjoint neural activations were of interest. The functional magnetic resonance imaging (fMRI) study focused on the neural networks involved in the processing of sexual stimuli in 21 male participants (11 homosexual, 10 heterosexual). Both groups viewed pictures with erotic content as well as aversive and neutral stimuli. The erotic pictures were subdivided into three categories (most sexually arousing, least sexually arousing, and rest) based on the individual subjective ratings of each participant. Blood oxygen level-dependent responses measured by fMRI and subjective ratings. A conjunction analysis revealed conjoint neural activation related to sexual arousal in thalamus, hypothalamus, occipital cortex, and nucleus accumbens. Increased insula, amygdala, and anterior cingulate gyrus activation could be linked to general arousal. Group differences emerged neither when viewing the most sexually arousing pictures compared with highly arousing aversive pictures nor compared with neutral pictures. Results suggest that a widespread neural network is activated by highly sexually arousing visual stimuli. A partly distinct network of structures underlies sexual and general arousal effects. The processing of preferred, highly sexually arousing stimuli recruited similar structures in homosexual and heterosexual males. © 2011 International Society for Sexual Medicine.

  19. What you see is what you want to see: Motivationally relevant stimuli can interrupt current resource allocation.

    Science.gov (United States)

    McSorley, Eugene; Morriss, Jayne

    2017-01-01

    Arousing stimuli, either threat-related or pleasant, may be selected for priority at different stages within the processing stream. Here we examine the pattern of processing for non-task-relevant threatening (spiders: arousing to some) and pleasant stimuli (babies or chocolate: arousing to all) by recording the gaze of a spider Fearful and Non-fearful group while they performed a simple "follow the cross" task. There was no difference in first saccade latencies. Saccade trajectories showed a general hypervigilance for all stimuli in the Fearful group. Saccade landing positions corresponded to what each group would find arousing, such that the Fearful group deviated towards both types of images whereas the Non-fearful group deviated towards pleasant images. Secondary corrective saccade latencies away from threat-related stimuli were longer for the Fearful group (difficulty in disengaging) compared with the Non-fearful group. These results suggest that attentional biases towards arousing stimuli may occur at different processing stages.

  20. Stimuli responsive nanomaterials for controlled release applications

    KAUST Repository

    Li, Song

    2012-01-01

    The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. Coupled with excellent biocompatibility profiles, various nanomaterials have showed great promise for biomedical applications. Stimuli-responsive nanomaterials guarantee the controlled release of cargo to a given location, at a specific time, and with an accurate amount. In this review, we have combined the major stimuli that are currently used to achieve the ultimate goal of controlled and targeted release by "smart" nanomaterials. The most heavily explored strategies include (1) pH, (2) enzymes, (3) redox, (4) magnetic, and (5) light-triggered release.

  1. The MR2: A multi-racial, mega-resolution database of facial stimuli.

    Science.gov (United States)

    Strohminger, Nina; Gray, Kurt; Chituc, Vladimir; Heffner, Joseph; Schein, Chelsea; Heagins, Titus Brooks

    2016-09-01

    Faces impart exhaustive information about their bearers, and are widely used as stimuli in psychological research. Yet many extant facial stimulus sets have substantially less detail than faces encountered in real life. In this paper, we describe a new database of facial stimuli, the Multi-Racial Mega-Resolution database (MR2). The MR2 includes 74 extremely high resolution images of European, African, and East Asian faces. This database provides a high-quality, diverse, naturalistic, and well-controlled facial image set for use in research. The MR2 is available under a Creative Commons license, and may be accessed online.

  2. Computer programming for generating visual stimuli.

    Science.gov (United States)

    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.

  3. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  4. Cerebral processing of auditory stimuli in patients with irritable bowel syndrome

    Institute of Scientific and Technical Information of China (English)

    Viola Andresen; Peter Kobelt; Claus Zimmer; Bertram Wiedenmann; Burghard F Klapp; Hubert Monnikes; Alexander Poellinger; Chedwa Tsrouya; Dominik Bach; Albrecht Stroh; Annette Foerschler; Petra Georgiewa; Marco Schmidtmann; Ivo R van der Voort

    2006-01-01

    AIM: To determine by brain functional magnetic resonance imaging (fMRI) whether cerebral processing of non-visceral stimuli is altered in irritable bowel syndrome (IBS) patients compared with healthy subjects. To circumvent spinal viscerosomatic convergence mechanisms,we used auditory stimulation, and to identify a possible influence of psychological factors the stimuli differed in their emotional quality.METHODS: In 8 IBS patients and 8 controls, fMRI measurements were performed using a block design of 4 auditory stimuli of different emotional quality (pleasant sounds of chimes, unpleasant peep (2000 Hz), neutral words, and emotional words). A gradient echo T2*-weighted sequence was used for the functional scans.Statistical maps were constructed using the general linear model.RESULTS: To emotional auditory stimuli, IBS patients relative to controls responded with stronger deactivations in a greater variety of emotional processing regions, while the response patterns, unlike in controls, did not differentiate between distressing or pleasant sounds.To neutral auditory stimuli, by contrast, only IBS patients responded with large significant activations.CONCLUSION: Altered cerebral response patterns to auditory stimuli in emotional stimulus-processing regions suggest that altered sensory processing in IBS may not be specific for visceral sensation, but might reflect generalized changes in emotional sensitivity and affectire reactivity, possibly associated with the psychological comorbidity often found in IBS patients.

  5. The joyful, yet balanced, amygdala: moderated responses to positive but not negative stimuli in trait happiness.

    Science.gov (United States)

    Cunningham, William A; Kirkland, Tabitha

    2014-06-01

    Although much is known about the neural dynamics of maladaptive affective styles, the mechanisms of happiness and well-being are less clear. One possibility is that the neural processes of trait happiness are the opposite of those involved in depression/anxiety: 'rose-colored glasses' cause happy people to focus on positive cues while remaining oblivious to threats. Specifically, because negative affective styles have been associated with increased amygdala activation to negative stimuli, it may be happy people will not show this enhanced response, and may even show reduced amygdala activation to negative stimuli. Alternatively, if well-being entails appropriate sensitivity to information, happy people may process any relevant cues-positive or negative-to facilitate appropriate responding. This would mean that happiness is associated with increased amygdala activation to both positive and negative stimuli. Forty-two participants viewed affective stimuli during functional magnetic resonance imaging scanning. Happier participants showed greater amygdala responses to positive stimuli. Moreover, no significant relationships were found between happiness and responses to negative stimuli. In other words, for happy people, a tuning toward positive did not come at the cost of losing sensitivity to negativity. This work suggests that trait happiness is associated with a balanced amygdala response to positivity and negativity. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  6. Discrimination training with multimodal stimuli changes activity in the mushroom body of the hawkmoth Manduca sexta.

    Directory of Open Access Journals (Sweden)

    Anna Balkenius

    Full Text Available BACKGROUND: The mushroom bodies of the insect brain play an important role in olfactory processing, associative learning and memory. The mushroom bodies show odor-specific spatial patterns of activity and are also influenced by visual stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Functional imaging was used to investigate changes in the in vivo responses of the mushroom body of the hawkmoth Manduca sexta during multimodal discrimination training. A visual and an odour stimulus were presented either together or individually. Initially, mushroom body activation patterns were identical to the odour stimulus and the multimodal stimulus. After training, however, the mushroom body response to the rewarded multimodal stimulus was significantly lower than the response to the unrewarded unimodal odour stimulus, indicating that the coding of the stimuli had changed as a result of training. The opposite pattern was seen when only the unimodal odour stimulus was rewarded. In this case, the mushroom body was more strongly activated by the multimodal stimuli after training. When no stimuli were rewarded, the mushroom body activity decreased for both the multimodal and unimodal odour stimuli. There was no measurable response to the unimodal visual stimulus in any of the experiments. These results can be explained using a connectionist model where the mushroom body is assumed to be excited by olfactory stimulus components, and suppressed by multimodal configurations. CONCLUSIONS: Discrimination training with multimodal stimuli consisting of visual and odour cues leads to stimulus specific changes in the in vivo responses of the mushroom body of the hawkmoth.

  7. Identifying Core Affect in Individuals from fMRI Responses to Dynamic Naturalistic Audiovisual Stimuli.

    Science.gov (United States)

    Kim, Jongwan; Wang, Jing; Wedell, Douglas H; Shinkareva, Svetlana V

    2016-01-01

    Recent research has demonstrated that affective states elicited by viewing pictures varying in valence and arousal are identifiable from whole brain activation patterns observed with functional magnetic resonance imaging (fMRI). Identification of affective states from more naturalistic stimuli has clinical relevance, but the feasibility of identifying these states on an individual trial basis from fMRI data elicited by dynamic multimodal stimuli is unclear. The goal of this study was to determine whether affective states can be similarly identified when participants view dynamic naturalistic audiovisual stimuli. Eleven participants viewed 5s audiovisual clips in a passive viewing task in the scanner. Valence and arousal for individual trials were identified both within and across participants based on distributed patterns of activity in areas selectively responsive to audiovisual naturalistic stimuli while controlling for lower level features of the stimuli. In addition, the brain regions identified by searchlight analyses to represent valence and arousal were consistent with previously identified regions associated with emotion processing. These findings extend previous results on the distributed representation of affect to multimodal dynamic stimuli.

  8. Identifying Core Affect in Individuals from fMRI Responses to Dynamic Naturalistic Audiovisual Stimuli

    Science.gov (United States)

    Kim, Jongwan; Wang, Jing; Wedell, Douglas H.

    2016-01-01

    Recent research has demonstrated that affective states elicited by viewing pictures varying in valence and arousal are identifiable from whole brain activation patterns observed with functional magnetic resonance imaging (fMRI). Identification of affective states from more naturalistic stimuli has clinical relevance, but the feasibility of identifying these states on an individual trial basis from fMRI data elicited by dynamic multimodal stimuli is unclear. The goal of this study was to determine whether affective states can be similarly identified when participants view dynamic naturalistic audiovisual stimuli. Eleven participants viewed 5s audiovisual clips in a passive viewing task in the scanner. Valence and arousal for individual trials were identified both within and across participants based on distributed patterns of activity in areas selectively responsive to audiovisual naturalistic stimuli while controlling for lower level features of the stimuli. In addition, the brain regions identified by searchlight analyses to represent valence and arousal were consistent with previously identified regions associated with emotion processing. These findings extend previous results on the distributed representation of affect to multimodal dynamic stimuli. PMID:27598534

  9. Blind Braille readers mislocate tactile stimuli.

    Science.gov (United States)

    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.

  10. Contingent stimuli signal subsequent reinforcer ratios.

    Science.gov (United States)

    Boutros, Nathalie; Davison, Michael; Elliffe, Douglas

    2011-07-01

    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 nonredundant in the frequently-changing preparation, and redundant in the steady-state arrangement. In the present experiments, 6 pigeons worked in a steady-state concurrent schedule procedure with nonredundant informative stimuli (red keylight illuminations). When a response-contingent red keylight signaled that the next food delivery was more likely on one of the two alternatives, postkeylight choice responding was reliably for that alternative. This effect was enhanced after a history of extended informative red keylight presentation (Experiment 2). These results lend support to recent characterizations of conditioned reinforcer effects as reflective of a discriminative, rather than a reinforcing, property of the stimulus.

  11. Discrimination of auditory stimuli during isoflurane anesthesia.

    Science.gov (United States)

    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.

  12. Photonic water dynamically responsive to external stimuli

    Science.gov (United States)

    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.

  13. Preparation of stimuli for timbre perception studies.

    Science.gov (United States)

    Labuschagne, Ilse B; Hanekom, Johan J

    2013-09-01

    Stimuli used in timbre perception studies must be controlled carefully in order to yield meaningful results. During psychoacoustic testing of individual timbre properties, (1) it must be ensured that timbre properties do not co-vary, as timbre properties are often not independent from one another, and (2) the potential influence of loudness, pitch, and perceived duration must be eliminated. A mathematical additive synthesis method is proposed which allows complete control over two spectral parameters, the spectral centroid (corresponding to brightness) and irregularity, and two temporal parameters, log rise-time (LRT) and a parameter characterizing the sustain/decay segment, while controlling for covariation in the spectral centroid and irregularity. Thirteen musical instrument sounds were synthesized. Perceptual data from six listeners indicate that variation in the four timbre properties mainly influences loudness and that perceived duration and pitch are not influenced significantly for the stimuli of longer duration (2 s) used here. Trends across instruments were found to be similar.

  14. Physiological responses induced by pleasant stimuli.

    Science.gov (United States)

    Watanuki, Shigeki; Kim, Yeon-Kyu

    2005-01-01

    The specific physiological responses induced by pleasant stimuli were investigated in this study. Various physiological responses of the brain (encephaloelectrogram; EEG), autonomic nervous system (ANS), immune system and endocrine system were monitored when pleasant stimuli such as odors, emotional pictures and rakugo, a typical Japanese comical story-telling, were presented to subjects. The results revealed that (i) EEG activities of the left frontal brain region were enhanced by a pleasant odor; (ii) emotional pictures related to primitive element such as nudes and erotic couples elevated vasomotor sympathetic nervous activity; and (iii) an increase in secretory immunoglobulin A (s-IgA) and a decrease in salivary cortisol (s-cortisol) were induced by rakugo-derived linguistic pleasant emotion. Pleasant emotion is complicated state. However, by considering the evolutionary history of human being, it is possible to assess and evaluate pleasant emotion from certain physiological responses by appropriately summating various physiological parameters.

  15. Cerebral processing of food-related stimuli: effects of fasting and gender.

    Science.gov (United States)

    Uher, Rudolf; Treasure, Janet; Heining, Maike; Brammer, Michael J; Campbell, Iain C

    2006-04-25

    To maintain nutritional homeostasis, external food-related stimuli have to be evaluated in relation to the internal states of hunger or satiety. To examine the neural circuitry responsible for integration of internal and external determinants of human eating behaviour, brain responses to visual and complex gustatory food-related stimuli were measured using functional magnetic resonance imaging in 18 healthy non-smokers (10 women, 8 men). Each individual was studied on two occasions, the order of which was counterbalanced; after eating as usual and after 24 h fasting. Raised plasma free fatty acids and lower insulin and leptin concentrations confirmed that participants fasted as requested. When fasted, participants reported more hunger, nervousness and worse mood and rated the visual (but not gustatory) food-related stimuli as more pleasant. The effect of fasting on hunger was stronger in women than in men. No circuitry was identified as differentially responsive in fasting compared to satiety to both visual and gustatory food-related stimuli. The left insula response to the gustatory stimuli was stronger during fasting. The inferior occipito-temporal response to visual food-related stimuli also tended to be stronger during fasting. The responses in the occipito-temporal cortex to visual and in the insula to gustatory stimuli were stronger in women than in men. There was no interaction between gender and fasting. In conclusion, food reactivity in modality-specific sensory cortical areas is modulated by internal motivational states. The stronger reactivity to external food-related stimuli in women may be explored as a marker of gender-related susceptibility to eating disorders.

  16. FMRI orientation decoding in V1 does not require global maps or globally coherent orientation stimuli

    Directory of Open Access Journals (Sweden)

    Arjen eAlink

    2013-08-01

    Full Text Available The orientation of a large grating can be decoded from V1 functional magnetic resonance imaging (fMRI data, even at low resolution (3-mm isotropic voxels. This finding has suggested that columnar-level neuronal information might be accessible to fMRI at 3T. However, orientation decodability might alternatively arise from global orientation-bias maps. Such global maps across V1 could result from bottom-up processing, if the preferences of V1 neurons were biased toward particular orientations (e.g. radial from fixation, or cardinal, i.e. vertical or horizontal. Global maps could also arise from local recurrent or top-down processing, reflecting pre-attentive perceptual grouping, attention spreading, or predictive coding of global form. Here we investigate whether fMRI orientation decoding with 2-mm voxels requires (a globally coherent orientation stimuli and/or (b global-scale patterns of V1 activity. We used opposite-orientation gratings (balanced about the cardinal orientations and spirals (balanced about the radial orientation, along with novel patch-swapped variants of these stimuli. The two stimuli of a patch-swapped pair have opposite orientations everywhere (like their globally coherent parent stimuli. However, the two stimuli appear globally similar, a patchwork of opposite orientations. We find that all stimulus pairs are robustly decodable, demonstrating that fMRI orientation decoding does not require globally coherent orientation stimuli. Furthermore, decoding remained robust after spatial high-pass filtering for all stimuli, showing that fine-grained components of the fMRI patterns reflect visual orientations. Consistent with previous studies, we found evidence for global radial and vertical bias maps in V1. However, these were weak or absent for patch-swapped stimuli, suggesting that global bias maps depend on globally coherent orientations and might arise through recurrent or top-down processes related to the perception of global

  17. Simulation of Stimuli-Responsive Polymer Networks

    Directory of Open Access Journals (Sweden)

    Thomas Gruhn

    2013-11-01

    Full Text Available The structure and material properties of polymer networks can depend sensitively on changes in the environment. There is a great deal of progress in the development of stimuli-responsive hydrogels for applications like sensors, self-repairing materials or actuators. Biocompatible, smart hydrogels can be used for applications, such as controlled drug delivery and release, or for artificial muscles. Numerical studies have been performed on different length scales and levels of details. Macroscopic theories that describe the network systems with the help of continuous fields are suited to study effects like the stimuli-induced deformation of hydrogels on large scales. In this article, we discuss various macroscopic approaches and describe, in more detail, our phase field model, which allows the calculation of the hydrogel dynamics with the help of a free energy that considers physical and chemical impacts. On a mesoscopic level, polymer systems can be modeled with the help of the self-consistent field theory, which includes the interactions, connectivity, and the entropy of the polymer chains, and does not depend on constitutive equations. We present our recent extension of the method that allows the study of the formation of nano domains in reversibly crosslinked block copolymer networks. Molecular simulations of polymer networks allow the investigation of the behavior of specific systems on a microscopic scale. As an example for microscopic modeling of stimuli sensitive polymer networks, we present our Monte Carlo simulations of a filament network system with crosslinkers.

  18. Anagrus breviphragma Soyka Short Distance Search Stimuli

    Directory of Open Access Journals (Sweden)

    Elisabetta Chiappini

    2015-01-01

    Full Text Available 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.

  19. Sex Differences in How Erotic and Painful Stimuli Impair Inhibitory Control

    Science.gov (United States)

    Yu, Jiaxin; Hung, Daisy L.; Tseng, Philip; Tzeng, Ovid J. L.; Muggleton, Neil G.; Juan, Chi-Hung

    2012-01-01

    Witnessing emotional events such as arousal or pain may impair ongoing cognitive processes such as inhibitory control. We found that this may be true only half of the time. Erotic images and painful video clips were shown to men and women shortly before a stop signal task, which measures cognitive inhibitory control. These stimuli impaired…

  20. Sex Differences in How Erotic and Painful Stimuli Impair Inhibitory Control

    Science.gov (United States)

    Yu, Jiaxin; Hung, Daisy L.; Tseng, Philip; Tzeng, Ovid J. L.; Muggleton, Neil G.; Juan, Chi-Hung

    2012-01-01

    Witnessing emotional events such as arousal or pain may impair ongoing cognitive processes such as inhibitory control. We found that this may be true only half of the time. Erotic images and painful video clips were shown to men and women shortly before a stop signal task, which measures cognitive inhibitory control. These stimuli impaired…

  1. Hot or not: Response inhibition reduces the hedonic value and motivational incentive of sexual stimuli

    Directory of Open Access Journals (Sweden)

    Anne E. Ferrey

    2012-12-01

    Full Text Available The motivational incentive of reward-related stimuli can become so salient that it drives behavior at the cost of other needs. Here we show that response inhibition applied during a Go/No-go task not only impacts hedonic evaluations but also reduces the behavioral incentive of motivationally-relevant stimuli. We first examined the impact of response inhibition on the hedonic value of sex stimuli associated with strong behavioral-approach responses (Experiment 1. Sexually-appealing and non-appealing images were both rated as less attractive when previously encountered as No-go (inhibited than as Go (non-inhibited items. We then discovered that inhibition reduces the motivational incentive of sexual appealing stimuli (Experiment 2. Prior Go/No-go status affected the number of key-presses by heterosexual males to view erotic-female (sexually-appealing but not erotic-male or scrambled-control (non-appealing images. These findings may provide an important foundation for developing inhibition-based interventions to reduce the hedonic value and motivational incentive of stimuli associated with disorders of self-control.

  2. Neural response to emotional stimuli during experimental human endotoxemia.

    Science.gov (United States)

    Kullmann, Jennifer S; Grigoleit, Jan-Sebastian; Lichte, Philipp; Kobbe, Philipp; Rosenberger, Christina; Banner, Christina; Wolf, Oliver T; Engler, Harald; Oberbeck, Reiner; Elsenbruch, Sigrid; Bingel, Ulrike; Forsting, Michael; Gizewski, Elke R; Schedlowski, Manfred

    2013-09-01

    Increases in peripheral cytokines during acute inflammation may affect various neuropsychological functions. The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the effects of acute endotoxemia on mood and the neural response to emotionally aversive visual stimuli in healthy human subjects. In a double-blind, randomized crossover study, 18 healthy males received a bolus injection of bacterial lipopolysaccharide (LPS; 0.4 ng/kg) or saline. Plasma levels of pro- and anti-inflammatory cytokines and cortisol as well as mood ratings were analyzed together with the blood-oxygen-level dependent (BOLD) response during the presentation of aversive versus neutral pictures. Endotoxin administration induced pronounced transient increases in plasma levels of TNF-α, IL-1ra, IL-6, IL-10, and cortisol. Positive mood was decreased and state anxiety increased. In addition, activation of right inferior orbitofrontal cortex (OFC) in response to emotional visual stimuli was significantly increased in the LPS condition. Increased prefrontal activation during the presentation of emotional material may reflect enhanced cognitive regulation of emotions as an adaptive response during an acute inflammation. These findings may have implications for the putative role of inflammatory processes in the pathophysiology of depression.

  3. Analyzing the user behavior towards Electronic Commerce stimuli

    Directory of Open Access Journals (Sweden)

    Carlota Lorenzo-Romero

    2016-11-01

    Full Text Available Based on the Stimulus-Organism-Response paradigm this research analyzes the main differences between the effects of two types of web technologies: Verbal web technology (i.e. navigational structure as utilitarian stimulus versus nonverbal web technology (music and presentation of products as hedonic stimuli. Specific webmosphere stimuli have not been examined yet as separate variables and their impact on internal and behavioral responses seems unknown. Therefore, the objective of this research consists in analyzing the impact of these web technologies –which constitute the web atmosphere or webmosphere of a website– on shopping human bebaviour (i.e. users’ internal states -affective, cognitive, and satisfaction- and behavioral responses - approach responses, and real shopping outcomes- within the retail online store created by computer, taking into account some mediator variables (i.e. involvement, atmospheric responsiveness, and perceived risk. A 2(free versus hierarchical navigational structure x2(on versus off music x2(moving versus static images between-subjects computer experimental design is used to test empirically this research. In addition, an integrated methodology was developed allowing the simulation, tracking and recording of virtual user behavior within an online shopping environment. As main conclusion, this study suggests that the positive responses of online consumers might increase when they are allowed to freely navigate the online stores and their experience is enriched by animate gifts and music background. The effect caused by mediator variables modifies relatively the final shopping human behavior.

  4. Analyzing the User Behavior toward Electronic Commerce Stimuli.

    Science.gov (United States)

    Lorenzo-Romero, Carlota; Alarcón-Del-Amo, María-Del-Carmen; Gómez-Borja, Miguel-Ángel

    2016-01-01

    Based on the Stimulus-Organism-Response paradigm this research analyzes the main differences between the effects of two types of web technologies: Verbal web technology (i.e., navigational structure as utilitarian stimulus) versus non-verbal web technology (music and presentation of products as hedonic stimuli). Specific webmosphere stimuli have not been examined yet as separate variables and their impact on internal and behavioral responses seems unknown. Therefore, the objective of this research consists in analyzing the impact of these web technologies -which constitute the web atmosphere or webmosphere of a website- on shopping human behavior (i.e., users' internal states -affective, cognitive, and satisfaction- and behavioral responses - approach responses, and real shopping outcomes-) within the retail online store created by computer, taking into account some mediator variables (i.e., involvement, atmospheric responsiveness, and perceived risk). A 2 ("free" versus "hierarchical" navigational structure) × 2 ("on" versus "off" music) × 2 ("moving" versus "static" images) between-subjects computer experimental design is used to test empirically this research. In addition, an integrated methodology was developed allowing the simulation, tracking and recording of virtual user behavior within an online shopping environment. As main conclusion, this study suggests that the positive responses of online consumers might increase when they are allowed to freely navigate the online stores and their experience is enriched by animate gifts and music background. The effect caused by mediator variables modifies relatively the final shopping human behavior.

  5. Response time to colored stimuli in the full visual field

    Science.gov (United States)

    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.

  6. Polymer-based stimuli-responsive nanosystems for biomedical applications.

    Science.gov (United States)

    Joglekar, Madhura; Trewyn, Brian G

    2013-08-01

    The application of organic polymers and inorganic/organic hybrid systems in numerous fields of biotechnology has seen a considerable growth in recent years. Typically, organic polymers with diverse structures, compositional variations and differing molecular weights have been utilized to assemble polymeric nanosystems such as polymeric micelles, polymersomes, and nanohydrogels with unique features and structural properties. The architecture of these polymeric nanosystems involves the use of both hydrophobic and hydrophilic polymeric blocks, making them suitable as vehicles for diagnostic and therapeutic applications. Recently, "smart" or "intelligent" polymers have attracted significant attention in the biomedical field wherein careful introduction of specific polymeric modalities changes a banal polymeric nanosystem to an advanced stimuli-responsive nanosystem capable of performing extraordinary functions in response to an internal or external trigger such as pH, temperature, redox, enzymes, light, magnetic, or ultrasound. Further, incorporation of inorganic nanoparticles such as gold, silica, or iron oxide with surface-bound stimuli-responsive polymers offers additional advantages and multifunctionality in the field of nanomedicine. This review covers the physical properties and applications of both organic and organic/inorganic hybrid nanosystems with specific recent breakthroughs in drug delivery, imaging, tissue engineering, and separations and provides a brief discussion on the future direction.

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

    Science.gov (United States)

    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.

  8. As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli.

    Science.gov (United States)

    Burley, Daniel T; Gray, Nicola S; Snowden, Robert J

    2017-01-01

    Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits.

  9. As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli

    Science.gov (United States)

    Gray, Nicola S.; Snowden, Robert J.

    2017-01-01

    Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits. PMID:28118366

  10. The influence of various distracting stimuli on spatial working memory

    Directory of Open Access Journals (Sweden)

    Martina Starc

    2016-01-01

    Full Text Available Protecting information from distraction is essential for optimal performance of working memory. We examined how the presence of distracting stimuli influences spatial working memory and compared the effect of both task-similar and negatively emotionally salient distractors. We checked the effect of distractors on the accuracy of high-resolution representations, as well as the maintenance of spatial categories, and more precisely defined not only the existence but also the direction of the distracting influences (towards or away from the position of the distractor. Participants (n = 25, 8 men, 19–31 years old were asked to remember the exact position of a target scrambled image and recall it with a joystick after a delay. In some trials an additional distracting image (scrambled, neutral or negative was shown during the delay. We measured the spread of responses (standard deviation of angular error and shifts of the average response towards the prototype angles (45° or towards the position of distractors. Distracting stimuli did not affect the spread of responses and decreased the tendency of participants to move the responses towards the prototype angle. Different types of distractors did not differ in this effect. Contrary to expectations, the participants moved their responses away from the position of distractors; this effect was more pronounced for negative distractors. In addition to memorizing the exact position and maintaining attention on the position of the stimulus, participants are likely to strategically use information about spatial category membership (quadrants and information about the position of the distractor. The repulsive effect of the distractor likely results from inhibition of its position and indicates the need to supplement computational models of spatial working memory and to take into account different strategies of working memory use.

  11. Stimuli-Responsive Block Copolymer-Based Assemblies for Cargo Delivery and Theranostic Applications

    Directory of Open Access Journals (Sweden)

    Jun Yin

    2016-07-01

    Full Text Available Although a number of tactics towards the fabrication and biomedical exploration of stimuli-responsive polymeric assemblies being responsive and adaptive to various factors have appeared, the controlled preparation of assemblies with well-defined physicochemical properties and tailor-made functions are still challenges. These responsive polymeric assemblies, which are triggered by stimuli, always exhibited reversible or irreversible changes in chemical structures and physical properties. However, simple drug/polymer nanocomplexes cannot deliver or release drugs into the diseased sites and cells on-demand due to the inevitable biological barriers. Hence, utilizing therapeutic or imaging agents-loaded stimuli-responsive block copolymer assemblies that are responsive to tumor internal microenvironments (pH, redox, enzyme, and temperature, etc. or external stimuli (light and electromagnetic field, etc. have emerged to be an important solution to improve therapeutic efficacy and imaging sensitivity through rationally designing as well as self-assembling approaches. In this review, we summarize a portion of recent progress in tumor and intracellular microenvironment responsive block copolymer assemblies and their applications in anticancer drug delivery and triggered release and enhanced imaging sensitivity. The outlook on future developments is also discussed. We hope that this review can stimulate more revolutionary ideas and novel concepts and meet the significant interest to diverse readers.

  12. An Exploration of Responses to Drug Conditioned Stimuli during Treatment for Substance Dependence

    Directory of Open Access Journals (Sweden)

    Benjamin Goddard

    2013-01-01

    Full Text Available Although it is well established that drug conditioned stimuli produce a variety of conditioned responses, it is not known whether such stimuli can also reinforce an arbitrary operant response and thus serve as conditioned reinforcers. Volunteers (n=39 recruited from a residential treatment center for substance dependence were tested on a task in which presses on computer keys activated images of drugs/drug paraphernalia on a progressive ratio schedule of reinforcement. They also completed a personalized craving questionnaire and a personalized Implicit Association Test. A significant bias in responding was found for images of preferred drugs/route of drug administration. Craving, however, was low and the images generated negative evaluative reactions. Two additional studies were performed to ascertain the generalizability of the effects to a different population of drug-using individuals (i.e., students who drink and to incentive stimuli of a different nature (i.e., sexual. The additional studies partially replicated and extended the central findings of the main study. Therefore, although these data should be considered preliminary in light of small group sizes, it is concluded that cue specificity and availability of the unconditioned stimuli (drugs and sex plays a role in modulating responding maintained by conditioned reinforcers.

  13. Emotion attribution to basic parametric static and dynamic stimuli

    NARCIS (Netherlands)

    Visch, V.; Goudbeek, M.B.; Cohn, J.; Nijholt, A.; Pantic, P.

    2009-01-01

    The following research investigates the effect of basic visual stimuli on the attribution of basic emotions by the viewer. In an empirical study (N = 33) we used two groups of visually minimal expressive stimuli: dynamic and static. The dynamic stimuli consisted of an animated circle moving

  14. Emotion attribution to basic parametric static and dynamic stimuli

    NARCIS (Netherlands)

    Visch, V.; Goudbeek, M.B.; Cohn, J.; Nijholt, A.; Pantic, P.

    2009-01-01

    The following research investigates the effect of basic visual stimuli on the attribution of basic emotions by the viewer. In an empirical study (N = 33) we used two groups of visually minimal expressive stimuli: dynamic and static. The dynamic stimuli consisted of an animated circle moving accordin

  15. The D2 antagonist sulpiride modulates the neural processing of both rewarding and aversive stimuli in healthy volunteers

    OpenAIRE

    2011-01-01

    Rationale Animal studies indicate that dopamine pathways in the ventral striatum code for the motivational salience of both rewarding and aversive stimuli, but evidence for this mechanism in humans is less established. We have developed a functional magnetic resonance imaging (fMRI) model which permits examination of the neural processing of both rewarding and aversive stimuli. Objectives The aim of the study was to determine the effect of the dopamine receptor antagonist, sulpiride, on the n...

  16. Recruitment of the intracellular Ca2+ by ultrashort electric stimuli: the impact of pulse duration.

    Science.gov (United States)

    Semenov, Iurii; Xiao, Shu; Pakhomova, Olga N; Pakhomov, Andrei G

    2013-09-01

    Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca2+ from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca2+ imaging with Fura-2. In a Ca(2+)-free medium, 10-, 60-, and 300-ns stimuli evoked Ca2+ transients by mobilization of Ca2+ from the endoplasmic reticulum. With 2 mM external Ca2+, the transients included both extra- and intracellular components. The recruitment of intracellular Ca2+ increased as the stimulus duration decreased. At the threshold of 200-300 nM, the transients were amplified by calcium-induced calcium release. We conclude that nanosecond stimuli mimic Ca2+ signaling while bypassing the usual receptor- and channels-mediated cascades. The recruitment of the intracellular Ca2+ can be controlled by the duration of the stimulus.

  17. Processing of pictorial food stimuli in patients with eating disorders--a systematic review.

    Science.gov (United States)

    Giel, Katrin Elisabeth; Teufel, Martin; Friederich, Hans-Christoph; Hautzinger, Martin; Enck, Paul; Zipfel, Stephan

    2011-03-01

    The processing of food cues in eating-disordered patients has recently been increasingly investigated. Outlined is current evidence from pictorial food stimuli studies. PubMed and PsychINFO were searched for quantitative pictorial food stimuli studies investigating healthy controls and expert-diagnosed eating-disordered patients. Patients with eating disorders (ED) demonstrated cue reactivity to food stimuli. Results from functional imaging suggest sensory disengagement and higher emotional involvement while self-reported data and facial EMG revealed that food pictures were perceived as less pleasurable. Different experimental paradigms have demonstrated an attentional bias for food cues in ED. Currently, psychophysiological data is widely inconclusive. Evidence suggests cue reactivity to food pictures in eating-disordered patients. However, the overall picture is inconclusive because methodological problems and the integration of findings from different experimental approaches pose a challenge to the research field. Copyright © 2009 Wiley Periodicals, Inc.

  18. Event-related potentials in response to 3-D auditory stimuli.

    Science.gov (United States)

    Fuchigami, Tatsuo; Okubo, Osami; Fujita, Yukihiko; Kohira, Ryutaro; Arakawa, Chikako; Endo, Ayumi; Haruyama, Wakako; Imai, Yuki; Mugishima, Hideo

    2009-09-01

    To evaluate auditory spatial cognitive function, age correlations for event-related potentials (ERPs) in response to auditory stimuli with a Doppler effect were studied in normal children. A sound with a Doppler effect is perceived as a moving audio image. A total of 99 normal subjects (age range, 4-21 years) were tested. In the task-relevant oddball paradigm, P300 and key-press reaction time were elicited using auditory stimuli (1000 Hz fixed and enlarged tones with a Doppler effect). From the age of 4 years, the P300 latency for the enlarged tone with a Doppler effect shortened more rapidly with age than did the P300 latency for tone-pips, and the latencies for the different conditions became similar towards the late teens. The P300 of auditory stimuli with a Doppler effect may be used to evaluate auditory spatial cognitive function in children.

  19. Reproducibility and discriminability of brain patterns of semantic categories enhanced by congruent audiovisual stimuli.

    Directory of Open Access Journals (Sweden)

    Yuanqing Li

    Full Text Available One of the central questions in cognitive neuroscience is the precise neural representation, or brain pattern, associated with a semantic category. In this study, we explored the influence of audiovisual stimuli on the brain patterns of concepts or semantic categories through a functional magnetic resonance imaging (fMRI experiment. We used a pattern search method to extract brain patterns corresponding to two semantic categories: "old people" and "young people." These brain patterns were elicited by semantically congruent audiovisual, semantically incongruent audiovisual, unimodal visual, and unimodal auditory stimuli belonging to the two semantic categories. We calculated the reproducibility index, which measures the similarity of the patterns within the same category. We also decoded the semantic categories from these brain patterns. The decoding accuracy reflects the discriminability of the brain patterns between two categories. The results showed that both the reproducibility index of brain patterns and the decoding accuracy were significantly higher for semantically congruent audiovisual stimuli than for unimodal visual and unimodal auditory stimuli, while the semantically incongruent stimuli did not elicit brain patterns with significantly higher reproducibility index or decoding accuracy. Thus, the semantically congruent audiovisual stimuli enhanced the within-class reproducibility of brain patterns and the between-class discriminability of brain patterns, and facilitate neural representations of semantic categories or concepts. Furthermore, we analyzed the brain activity in superior temporal sulcus and middle temporal gyrus (STS/MTG. The strength of the fMRI signal and the reproducibility index were enhanced by the semantically congruent audiovisual stimuli. Our results support the use of the reproducibility index as a potential tool to supplement the fMRI signal amplitude for evaluating multimodal integration.

  20. Spontaneously Emerging Patterns in Human Visual Cortex Reflect Responses to Naturalistic Sensory Stimuli.

    Science.gov (United States)

    Wilf, Meytal; Strappini, Francesca; Golan, Tal; Hahamy, Avital; Harel, Michal; Malach, Rafael

    2017-01-01

    In the absence of stimulus or task, the cortex spontaneously generates rich and consistent functional connectivity patterns (termed resting state networks) which are evident even within individual cortical areas. We and others have previously hypothesized that habitual cortical network activations during daily life contribute to the shaping of these connectivity patterns. Here we tested this hypothesis by comparing, using blood oxygen level-dependent-functional magnetic resonance imaging, the connectivity patterns that spontaneously emerge during rest in retinotopic visual areas to the patterns generated by naturalistic visual stimuli (repeated movie segments). These were then compared with connectivity patterns produced by more standard retinotopic mapping stimuli (polar and eccentricity mapping). Our results reveal that the movie-driven patterns were significantly more similar to the spontaneously emerging patterns, compared with the connectivity patterns of either eccentricity or polar mapping stimuli. Intentional visual imagery of naturalistic stimuli was unlikely to underlie these results, since they were duplicated when participants were engaged in an auditory task. Our results suggest that the connectivity patterns that appear during rest better reflect naturalistic activations rather than controlled, artificially designed stimuli. The results are compatible with the hypothesis that the spontaneous connectivity patterns in human retinotopic areas reflect the statistics of cortical coactivations during natural vision. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. Agnosia for mirror stimuli: a new case report with a small parietal lesion.

    Science.gov (United States)

    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. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Intercepting the first pass: rapid categorization is suppressed for unseen stimuli

    Directory of Open Access Journals (Sweden)

    Lisandro Nicolas Kaunitz

    2011-08-01

    Full Text Available The operations and processes that the human brain employs to achieve fast visual categorizationremain a matter of debate. A first issue concerns the timing and place of rapid visual categorizationand to what extent it can be performed with an early feed-forward pass of information throughthe visual system. A second issue involves the categorization of stimuli that do not reach visualawareness. There is disagreement over the degree to which these stimuli activate the same earlymechanisms as stimuli that are consciously perceived. We employed continuous flash suppression,EEG recordings and machine learning techniques to study visual categorization of seen and unseenstimuli. Our classifiers were able to predict from the EEG recordings the category of stimuli onseen trials but not on unseen trials. Rapid categorization of conscious images could be detectedaround 100 ms on the occipital electrodes, consistent with a fast, feed-forward mechanism of targetdetection. For the invisible stimuli, however, continuous flash suppression eliminated all traces ofearly processing. Our results support the idea of a fast mechanism of categorization and suggestthat this early categorization process plays an important role in later, more subtle categorizationsand perceptual processes.

  3. Termination of pinned spirals by local stimuli

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. Enhanced Recognition Memory in Grapheme-Colour Synaesthesia for Different Categories of Visual Stimuli

    Directory of Open Access Journals (Sweden)

    Jamie eWard

    2013-10-01

    Full Text Available Memory has been shown to be enhanced in grapheme-colour synaesthesia, and this enhancement extends to certain visual stimuli (that don’t induce synaesthesia as well as stimuli comprised of graphemes (which do. Previous studies have used a variety of testing procedures to assess memory in synaesthesia (e.g. free recall, recognition, associative learning making it hard to know the extent to which memory benefits are attributable to the stimulus properties themselves, the testing method, participant strategies, or some combination of these factors. In the first experiment, we use the same testing procedure (recognition memory for a variety of stimuli (written words, nonwords, scenes, and fractals and also check which memorisation strategies were used. We demonstrate that grapheme-colour synaesthetes show enhanced memory across all these stimuli, but this is not found for a non-visual type of synaesthesia (lexical-gustatory. In the second experiment, the memory advantage for scenes is explored further by manipulating the properties of the old and new images (changing colour, orientation, or object presence. Again, grapheme-colour synaesthetes show a memory advantage for scenes across all manipulations. Although recognition memory is generally enhanced in this study, the largest effects were found for abstract visual images (fractals and scenes for which colour can be used to discriminate old/new status.

  6. Enhanced recognition memory in grapheme-color synaesthesia for different categories of visual stimuli.

    Science.gov (United States)

    Ward, Jamie; Hovard, Peter; Jones, Alicia; Rothen, Nicolas

    2013-01-01

    Memory has been shown to be enhanced in grapheme-color synaesthesia, and this enhancement extends to certain visual stimuli (that don't induce synaesthesia) as well as stimuli comprised of graphemes (which do). Previous studies have used a variety of testing procedures to assess memory in synaesthesia (e.g., free recall, recognition, associative learning) making it hard to know the extent to which memory benefits are attributable to the stimulus properties themselves, the testing method, participant strategies, or some combination of these factors. In the first experiment, we use the same testing procedure (recognition memory) for a variety of stimuli (written words, non-words, scenes, and fractals) and also check which memorization strategies were used. We demonstrate that grapheme-color synaesthetes show enhanced memory across all these stimuli, but this is not found for a non-visual type of synaesthesia (lexical-gustatory). In the second experiment, the memory advantage for scenes is explored further by manipulating the properties of the old and new images (changing color, orientation, or object presence). Again, grapheme-color synaesthetes show a memory advantage for scenes across all manipulations. Although recognition memory is generally enhanced in this study, the largest effects were found for abstract visual images (fractals) and scenes for which color can be used to discriminate old/new status.

  7. Analyzing the User Behavior toward Electronic Commerce Stimuli

    Science.gov (United States)

    Lorenzo-Romero, Carlota; Alarcón-del-Amo, María-del-Carmen; Gómez-Borja, Miguel-Ángel

    2016-01-01

    Based on the Stimulus-Organism-Response paradigm this research analyzes the main differences between the effects of two types of web technologies: Verbal web technology (i.e., navigational structure as utilitarian stimulus) versus non-verbal web technology (music and presentation of products as hedonic stimuli). Specific webmosphere stimuli have not been examined yet as separate variables and their impact on internal and behavioral responses seems unknown. Therefore, the objective of this research consists in analyzing the impact of these web technologies –which constitute the web atmosphere or webmosphere of a website– on shopping human behavior (i.e., users’ internal states -affective, cognitive, and satisfaction- and behavioral responses – approach responses, and real shopping outcomes-) within the retail online store created by computer, taking into account some mediator variables (i.e., involvement, atmospheric responsiveness, and perceived risk). A 2 (“free” versus “hierarchical” navigational structure) × 2 (“on” versus “off” music) × 2 (“moving” versus “static” images) between-subjects computer experimental design is used to test empirically this research. In addition, an integrated methodology was developed allowing the simulation, tracking and recording of virtual user behavior within an online shopping environment. As main conclusion, this study suggests that the positive responses of online consumers might increase when they are allowed to freely navigate the online stores and their experience is enriched by animate gifts and music background. The effect caused by mediator variables modifies relatively the final shopping human behavior. PMID:27965549

  8. Internal reliability of the alcohol-related visual probe task is increased by utilising personalised stimuli and eye-tracking.

    Science.gov (United States)

    Christiansen, Paul; Mansfield, Rosie; Duckworth, Jay; Field, Matt; Jones, Andrew

    2015-10-01

    In the current study, we investigated whether the internal reliability of the visual probe task measure of attentional bias for substance-related cues could be improved by incorporating eye-tracking methods and personalised stimuli. Sixty social drinkers completed two visual probe tasks: one with a broad range of different alcohol pictures, the other containing only images of the participants' preferred drink. Attentional bias was inferred from manual reaction times to probes replacing the pictures, and from the duration of eye movement fixations towards the pictures (gaze dwell time). Internal reliability was highest for personalised (versus general) alcohol stimuli, and for eye-tracking (versus manual reaction time) measures of attentional bias. The internal reliability of both reaction time (α=.73) and gaze dwell time measures (α=.76) of attentional bias for personalised alcohol stimuli was acceptable. Internal reliability of indices of attentional bias for general alcohol stimuli was inferior, although better for the gaze dwell time (α=.51) compared to the reaction time measure (α=.19). Attentional bias towards personalised stimuli was larger than bias to general stimuli, but only for the reaction time measure. There were no statistically significant associations between measures of attentional bias and alcohol consumption or craving. Adopting personalised stimuli and eye movement monitoring significantly improves the internal reliability of the alcohol-related visual probe task. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Unconscious neural processing differs with method used to render stimuli invisible

    Directory of Open Access Journals (Sweden)

    Sergey Victor Fogelson

    2014-06-01

    Full Text Available Visual stimuli can be kept from awareness using various methods. The extent of processing that a given stimulus receives in the absence of awareness is typically used to make claims about the role of consciousness more generally. The neural processing elicited by a stimulus, however, may also depend on the method used to keep it from awareness, and not only on whether the stimulus reaches awareness. Here we report that the method used to render an image invisible has a dramatic effect on how category information about the unseen stimulus is encoded across the human brain. We collected fMRI data while subjects viewed images of faces and tools, that were rendered invisible using either continuous flash suppression (CFS or chromatic flicker fusion (CFF. In a third condition, we presented the same images under normal fully visible viewing conditions. We found that category information about visible images could be extracted from patterns of fMRI responses throughout areas of neocortex known to be involved in face or tool processing. However, category information about stimuli kept from awareness using CFS could be recovered exclusively within occipital cortex, whereas information about stimuli kept from awareness using CFF was also decodable within temporal and frontal regions. We conclude that unconsciously presented objects are processed differently depending on how they are rendered subjectively invisible. Caution should therefore be used in making generalizations on the basis of any one method about the neural basis of consciousness or the extent of information processing without consciousness.

  10. Gender differences in associations of sexual and romantic stimuli: do young men really prefer sex over romance?

    Science.gov (United States)

    Thompson, Ashley E; O'Sullivan, Lucia F

    2012-08-01

    Theory and research emphasize differences in men's and women's sexual and romantic attitudes, concluding that men have stronger preferences for sexual than romantic stimuli as compared to women. However, most of the research on gender differences have relied on self-reports, which are plagued by problems of social desirability bias. The current study assessed young men's and women's implicit attitudes toward sexual and romantic stimuli to test whether, in fact, men have a stronger preference for sexual over romantic stimuli compared to women. We also assessed associations between implicit and explicit attitudes, as well as sex role ideology and personality. College students (68 men and 114 women) completed an Implicit Association Test (IAT) that assessed strengths of associations of sexual and romantic stimuli to both pleasant and unpleasant conditions. Results revealed that both men and women more strongly associated romantic images to the pleasant condition than they associated the sexual images to the pleasant condition. However, as predicted, women had a stronger preference toward romantic versus sexual stimuli compared to men. Our study challenges a common assumption that men prefer sexual over romantic stimuli. The findings indicate that measures of implicit attitudes may tap preferences that are not apparent in studies relying on self-reported (explicit) attitudes.

  11. Approach motivation and cognitive resources combine to influence memory for positive emotional stimuli.

    Science.gov (United States)

    Crowell, Adrienne; Schmeichel, Brandon J

    2016-01-01

    Inspired by the elaborated intrusion theory of desire, the current research tested the hypothesis that persons higher in trait approach motivation process positive stimuli deeply, which enhances memory for them. Ninety-four undergraduates completed a measure of trait approach motivation, viewed positive or negative image slideshows in the presence or absence of a cognitive load, and one week later completed an image memory test. Higher trait approach motivation predicted better memory for the positive slideshow, but this memory boost disappeared under cognitive load. Approach motivation did not influence memory for the negative slideshow. The current findings support the idea that individuals higher in approach motivation spontaneously devote limited resources to processing positive stimuli.

  12. Valuation of Go Stimuli or Devaluation of No-Go Stimuli? Evidence of an Increased Preference for Attended Go Stimuli Following a Go/No-Go Task.

    Science.gov (United States)

    Inoue, Kazuya; Sato, Nobuya

    2017-01-01

    Attentional inhibition that occurs during discrimination tasks leads to the negative evaluation of distractor stimuli. This phenomenon, known as the distractor devaluation effect also occurs when go/no-go tasks require response inhibition. However, it remains unclear whether there are interactions between attention and response controls when the distractor devaluation effect occurs. The aims of this study were to investigate whether attention to stimuli in the go/no-go task plays a facilitative role in distractor devaluation through response inhibition, and to clarify whether this effect reflects a decreased preference for no-go stimuli. Participants evaluated the preference for pictures before and after a go/no-go task. In Experiments 1 and 2, they made a go or no-go response depending on the category of pictures displayed (gummy candies or rice crackers), whereas in Experiment 3 they did on the basis digit category, even or odd numbers, superimposed on such pictures. Experiments 1 and 2 demonstrated that the pictures presented as no-go stimuli in the preceding go/no-go task were evaluated as less positive than the pictures presented as go stimuli. This devaluation effect reflected an increased preference for the go stimuli but not a decreased preference for the no-go stimuli. Experiment 3 indicated that response inhibition did not affect the preference for the pictures that had not received attention in a preceding go/no-go task. These results suggest that although attention plays an important role in differential ratings for go and no-go stimuli, such differences, in fact, reflect the valuation of go stimuli.

  13. Complexities of Emotional Responses to Social and Nonsocial Affective Stimuli in Schizophrenia

    Directory of Open Access Journals (Sweden)

    Joel S. Peterman

    2015-03-01

    Full Text Available BACKGROUND: Adaptive emotional responses are important in interpersonal relationships. We investigated self-reported emotional experience, physiological reactivity, and micro-facial expressivity in relation to the social nature of stimuli in individuals with schizophrenia.METHOD: Galvanic skin response (GSR and facial electromyography (fEMG were recorded in medicated outpatients with schizophrenia (SZ and demograph-ically-matched healthy controls (CO while they viewed social and non-social im-ages from the International Affective Pictures System (IAPS. Participants rated the valence and arousal, and selected a label for experienced emotions. Symp-tom severity in the SZ, and schizotypy in CO were assessed.RESULTS: The two groups did not differ in their labeling of the emotions evoked by the stimuli, but individuals with schizophrenia were more positive in their va-lence ratings. Although self-reported arousal was similar in both groups, GSR was greater in schizophrenia, suggesting differential awareness or calibration of internal states. Both groups reported social images to be more arousing than non-social images but their physiological responses to nonsocial vs. social imag-es were different. Self-reported arousal to neutral social images was correlated with positive symptoms in schizophrenia. Negative symptoms in SZ and disor-ganized schizotypy in CO were associated with reduced fEMG. Greater corruga-tor fEMG activity for positive images in SZ indicates valence-incongruent facial expressions.CONCLUSIONS: The patterns of emotional responses differed between the two groups. While both groups were in broad agreement in self-reported arousal and emotion labels, their GSR and fEMG correlates of emotion diverged in relation to the social nature of the stimuli and clinical measures. Importantly, these results suggest disrupted self awareness of internal states in schizophrenia and under-score the complexities of emotion processing in health and

  14. Chicks prefer to peck at insect-like elongated stimuli moving in a direction orthogonal to their longer axis.

    Science.gov (United States)

    Clara, Elena; Regolin, Lucia; Vallortigara, Giorgio; Rogers, Lesley J

    2009-11-01

    Spontaneous preferences towards possible prey have been little investigated using targets in motion. Preferences of domestic chicks (Gallus gallus) to peck at video-images of stimuli representing live insects moving along their longer body axis (i.e. "forwards") or along the shorter body axis (i.e. "sideways") were investigated. Chicks presented with both types of stimulus displayed a significant preference for pecking at stimuli moving sideways. This preference was already present on day 1 post-hatching, and it strengthened on day 6 for those chicks that had experienced pecking at live insects. Head angles used to fixate the stimuli prior to pecking were also analysed and were consistent (i.e. 30 degrees -35 degrees and 60 degrees -65 degrees ) with those reported for fixation of non-edible targets (larger stimuli at a distance). In a first control experiment the same video-presented stimuli were used but the insect's legs were removed to reduce flickering. In a second control experiment, paper-printed images of the whole insect were used. In both cases, the sideways direction of movement was clearly preferred. Overall, our data show that chicks have a spontaneous preference to peck at video-images resembling live insects moving along their shorter body axis. Sideways movement may constitute a crucial signal attracting chicks' attention and enhancing predatory responses possibly because of stronger stimulation of motion detectors.

  15. Happiness increases distraction by auditory deviant stimuli.

    Science.gov (United States)

    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. © 2015 The British Psychological Society.

  16. Psychophysiological response patterns to affective film stimuli.

    Directory of Open Access Journals (Sweden)

    Marieke G N Bos

    Full Text Available Psychophysiological research on emotion utilizes various physiological response measures to index activation of the defense system. Here we tested 1 whether acoustic startle reflex (ASR, skin conductance response (SCR and heart rate (HR elicited by highly arousing stimuli specifically reflect a defensive state and 2 the relation between resting heart rate variability (HRV and affective responding. In a within-subject design, participants viewed film clips with a positive, negative and neutral content. In contrast to SCR and HR, we show that ASR differentiated between negative, neutral and positive states and can therefore be considered as a reliable index of activation of the defense system. Furthermore, resting HRV was associated with affect-modulated characteristics of ASR, but not with SCR or HR. Interestingly, individuals with low-HRV showed less differentiation in ASR between affective states. We discuss the important value of ASR in psychophysiological research on emotion and speculate on HRV as a potential biological marker for demarcating adaptive from maladaptive responding.

  17. Stimuli-responsive cement-reinforced rubber.

    Science.gov (United States)

    Musso, Simone; Robisson, Agathe; Maheshwar, Sudeep; Ulm, Franz-Josef

    2014-05-14

    In this work, we report the successful development of a cement-rubber reactive composite with reversible mechanical properties. Initially, the composite behaves like rubber containing inert filler, but when exposed to water, it increases in volume and reaches a stiffness that is intermediate between that of hydrogenated nitrile butadiene rubber (HNBR) and hydrated cement, while maintaining a relatively large ductility characteristic of rubber. After drying, the modulus increases even further up to 400 MPa. Wet/drying cycles prove that the elastic modulus can reversibly change between 150 and 400 MPa. Utilizing attenuated total reflection Fourier transform infrared spectroscopy), we demonstrate that the high pH produced by the hydration of cement triggers the hydrolysis of the rubber nitrile groups into carboxylate anions. Thus, the salt bridges, generated between the carboxylate anions of the elastomer and the cations of the filler, are responsible for the reversible variations in volume and elastic modulus of the composite as a consequence of environmental moisture exposure. These results reveal that cement nanoparticles can successfully be used to accomplish a twofold task: (a) achieve an original postpolymerization modification that allows one to work with carboxylate HNBR (HXNBR) not obtained by direct copolymerization of carboxylate monomers with butadiene, and (b) synthesize a stimuli-responsive polymeric composite. This new type of material, having an ideal behavior for sealing application, could be used as an alternative to cement for oil field zonal isolation applications.

  18. Anchoring in Numeric Judgments of Visual Stimuli.

    Science.gov (United States)

    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. Processing of voiced and unvoiced acoustic stimuli in musicians

    Directory of Open Access Journals (Sweden)

    Cyrill Guy Martin Ott

    2011-09-01

    Full Text Available 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 (VOT. Using high-density EEG recordings we analysed the neurophysiological responses to voiced and unvoiced CV syllables and noise analogues in 26 German speaking adult musicians and non-musicians. From the EEG the N1 amplitude of the event-related potential (ERP 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. We propose that musicians utilise the same network to analyse 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.

  20. How Does Temporal Frequency Affect Impression Formation for Audio-Visual Stimuli?

    Directory of Open Access Journals (Sweden)

    Miharu Yamada

    2011-10-01

    Full Text Available In this study, we examined the effects of the temporal frequency of the audio–visual stimuli on the impression formation and perception of the temporal congruency. In our previous study (2010 with two temporal frequency conditions (108, and 216bpm, we found that both the processing which underlies the impression formation of the temporal congruency and the processing which underlies the perceptual judgment depend not only upon the time lag between the audio and visual stimuli but also upon the temporal frequency of the stimuli. As visual stimulus, we used repetitive luminance change of the computer graphic image with a constant temporal frequency (87, 108, 146, or 216bpm. As audio stimulus, we used periodic drum sounds consisting of a low tam and three cymbals. There were nine conditions for asynchrony between the visual and audio stimuli (±0, 96, 192, 288, and 384ms. We found that the range of the audio-visual asynchrony for the temporal congruent impression is much narrower than the range for the temporal congruent perception. These results suggest that the perception of the temporal congruency does not determine the impression formation for the temporal congruency.

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

    Science.gov (United States)

    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…

  2. Inverse Target- and Cue-Priming Effects of Masked Stimuli

    Science.gov (United States)

    Mattler, Uwe

    2007-01-01

    The processing of a visual target that follows a briefly presented prime stimulus can be facilitated if prime and target stimuli are similar. In contrast to these positive priming effects, inverse priming effects (or negative compatibility effects) have been found when a mask follows prime stimuli before the target stimulus is presented: Responses…

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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. Gender differences in identifying emotions from auditory and visual stimuli.

    Science.gov (United States)

    Waaramaa, Teija

    2017-12-01

    The present study focused on gender differences in emotion identification from auditory and visual stimuli produced by two male and two female actors. Differences in emotion identification from nonsense samples, language samples and prolonged vowels were investigated. It was also studied whether auditory stimuli can convey the emotional content of speech without visual stimuli, and whether visual stimuli can convey the emotional content of speech without auditory stimuli. The aim was to get a better knowledge of vocal attributes and a more holistic understanding of the nonverbal communication of emotion. Females tended to be more accurate in emotion identification than males. Voice quality parameters played a role in emotion identification in both genders. The emotional content of the samples was best conveyed by nonsense sentences, better than by prolonged vowels or shared native language of the speakers and participants. Thus, vocal non-verbal communication tends to affect the interpretation of emotion even in the absence of language. The emotional stimuli were better recognized from visual stimuli than auditory stimuli by both genders. Visual information about speech may not be connected to the language; instead, it may be based on the human ability to understand the kinetic movements in speech production more readily than the characteristics of the acoustic cues.

  6. Bayesian-based integration of multisensory naturalistic perithreshold stimuli.

    Science.gov (United States)

    Regenbogen, Christina; Johansson, Emilia; Andersson, Patrik; Olsson, Mats J; Lundström, Johan N

    2016-07-29

    Most studies exploring multisensory integration have used clearly perceivable stimuli. According to the principle of inverse effectiveness, the added neural and behavioral benefit of integrating clear stimuli is reduced in comparison to stimuli with degraded and less salient unisensory information. Traditionally, speed and accuracy measures have been analyzed separately with few studies merging these to gain an understanding of speed-accuracy trade-offs in multisensory integration. In two separate experiments, we assessed multisensory integration of naturalistic audio-visual objects consisting of individually-tailored perithreshold dynamic visual and auditory stimuli, presented within a multiple-choice task, using a Bayesian Hierarchical Drift Diffusion Model that combines response time and accuracy. For both experiments, unisensory stimuli were degraded to reach a 75% identification accuracy level for all individuals and stimuli to promote multisensory binding. In Experiment 1, we subsequently presented uni- and their respective bimodal stimuli followed by a 5-alternative-forced-choice task. In Experiment 2, we controlled for low-level integration and attentional differences. Both experiments demonstrated significant superadditive multisensory integration of bimodal perithreshold dynamic information. We present evidence that the use of degraded sensory stimuli may provide a link between previous findings of inverse effectiveness on a single neuron level and overt behavior. We further suggest that a combined measure of accuracy and reaction time may be a more valid and holistic approach of studying multisensory integration and propose the application of drift diffusion models for studying behavioral correlates as well as brain-behavior relationships of multisensory integration.

  7. Processing of natural temporal stimuli by macaque retinal ganglion cells

    NARCIS (Netherlands)

    Hateren, J.H. van; Rüttiger, L.; Lee, B.B.

    2002-01-01

    This study quantifies the performance of primate retinal ganglion cells in response to natural stimuli. Stimuli were confined to the temporal and chromatic domains and were derived from two contrasting environments, one typically northern European and the other a flower show. The performance of the

  8. Processing of natural temporal stimuli by macaque retinal ganglion cells

    NARCIS (Netherlands)

    Hateren, J.H. van; Rüttiger, L.; Lee, B.B.

    2002-01-01

    This study quantifies the performance of primate retinal ganglion cells in response to natural stimuli. Stimuli were confined to the temporal and chromatic domains and were derived from two contrasting environments, one typically northern European and the other a flower show. The performance of the

  9. Stimuli-Regulated Smart Polymeric Systems for Gene Therapy

    Directory of Open Access Journals (Sweden)

    Ansuja Pulickal Mathew

    2017-04-01

    Full Text Available The physiological condition of the human body is a composite of different environments, each with its own parameters that may differ under normal, as well as diseased conditions. These environmental conditions include factors, such as pH, temperature and enzymes that are specific to a type of cell, tissue or organ or a pathological state, such as inflammation, cancer or infection. These conditions can act as specific triggers or stimuli for the efficient release of therapeutics at their destination by overcoming many physiological and biological barriers. The efficacy of conventional treatment modalities can be enhanced, side effects decreased and patient compliance improved by using stimuli-responsive material that respond to these triggers at the target site. These stimuli or triggers can be physical, chemical or biological and can be internal or external in nature. Many smart/intelligent stimuli-responsive therapeutic gene carriers have been developed that can respond to either internal stimuli, which may be normally present, overexpressed or present in decreased levels, owing to a disease, or to stimuli that are applied externally, such as magnetic fields. This review focuses on the effects of various internal stimuli, such as temperature, pH, redox potential, enzymes, osmotic activity and other biomolecules that are present in the body, on modulating gene expression by using stimuli-regulated smart polymeric carriers.

  10. Stimuli-Responsive Liposomes for Controlled Drug Delivery

    KAUST Repository

    Li, Wengang

    2014-09-01

    Liposomes are promising drug delivery vesicles due to their biodegradibility, large volume and biocompatibility towards both hydrophilic and hydrophobic drugs. They suffer, however, from poor stability which limits their use in controlled delivery applications. Herein, a novel method was devised for modification of liposomes with small molecules, polymers or nanoparticles to afford stimuli responsive systems that release on demand and stay relatively stable in the absence of the trigger.. This dissertation discusses thermosensitive, pH sensitive, light sensitive and magnetically triggered liposomes that have been prepared for controlled drug delivery application. RAFT polymerization was utilized for the preparation of thermosensitive liposomes (Cholesterol-PNIPAm) and acid-labile liposomes (DOPE-PAA). With low Mw Cholesterol-PNIPAm, the thermosensitive liposomes proved to be effective for controlled release and decreased the cytotoxicity of PNIPAm by eliciting the polymer doses. By crosslinking the DOPE-PAA on liposome surface with acid-labile diamine linkers, DOPE-PAA liposomes were verified to be sensitive at low pH. The effects of polymer structures (linear or hyperbranched) have also been studied for the stability and release properties of liposomes. Finally, a dual-responsive Au@SPIO embedded liposome hybrid (ALHs) was prepared with light-induced “on-and-off” function by photo-thermal process (visible light) and instant release properties triggered by alternating magnetic field, respectively. The ALH system would be further applied into the cellular imaging field as MRI contrast agent.

  11. Secondary hyperalgesia to heat stimuli after burn injury in man

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    was not significantly different between the two zones of hyperalgesia. In conclusion, secondary hyperalgesia in man is not restricted to mechanical stimuli, as significant hyperalgesia to heat developed within the zone of secondary hyperalgesia to punctate mechanical stimuli. The data, combined with other evidence......The aim of the study was to examine the presence of hyperalgesia to heat stimuli within the zone of secondary hyperalgesia to punctate mechanical stimuli. A burn was produced on the medial part of the non-dominant crus in 15 healthy volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min......), and assessments were made 70 min and 40 min before, and 0, 1, and 2 h after the burn injury. Hyperalgesia to mechanical and heat stimuli were examined by von Frey hairs and contact thermodes (3.75 and 12.5 cm2), and pain responses were rated with a visual analog scale (0-100). The area of secondary hyperalgesia...

  12. Secondary hyperalgesia to heat stimuli after burn injury in man

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    area). The burns decreased pain thresholds and increased pain responses to both thermal and mechanical stimuli within the burn (P hyperalgesia (mean 89 cm2) to punctate mechanical stimuli (P ...The aim of the study was to examine the presence of hyperalgesia to heat stimuli within the zone of secondary hyperalgesia to punctate mechanical stimuli. A burn was produced on the medial part of the non-dominant crus in 15 healthy volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min......), and assessments were made 70 min and 40 min before, and 0, 1, and 2 h after the burn injury. Hyperalgesia to mechanical and heat stimuli were examined by von Frey hairs and contact thermodes (3.75 and 12.5 cm2), and pain responses were rated with a visual analog scale (0-100). The area of secondary hyperalgesia...

  13. Effects of mechanical stimuli on adaptive remodeling of condylar cartilage.

    Science.gov (United States)

    Sriram, D; Jones, A; Alatli-Burt, I; Darendeliler, M A

    2009-05-01

    Trabecular bone has been shown to be responsive to low-magnitude, high-frequency mechanical stimuli. This study aimed to assess the effects of these stimuli on condylar cartilage and its endochondral bone. Forty female 12-week-old C3H mice were divided into 3 groups: baseline control (killed at day 0), sham (killed at day 28 without exposure to mechanical stimuli), and experimental (killed following 28 days of exposure to mechanical stimuli). The experimental group was subjected to mechanical vibration of 30 Hz, for 20 minutes per day, 5 days per week, for 28 days. The specimens were analyzed by micro-computed tomography. The experimental group demonstrated a significant decrease in the volume of condylar cartilage and also a significant increase in bone histomorphometric parameters. The results suggest that the low-magnitude, high-frequency mechanical stimuli enhance adaptive remodeling of condylar cartilage, evidenced by the advent of endochondral bone replacing the hypertrophic cartilage.

  14. Modulation of Motion Perception of Ipsilateral Tactile Stimuli Using Sound

    Directory of Open Access Journals (Sweden)

    Yuika Suzuki

    2011-10-01

    Full Text Available We report the modulation of tactile motion perception by presenting static sounds with two alternately and repeatedly presented vibrotactile stimuli for the perception of tactile apparent motion. Previous research on tactile motion perception has used direction judgment tasks for apparent motion that consist of two non-repeating, or more than two repeating stimuli. However, the direction of two repeating apparent motion stimuli has been considered too ambiguous to be judged. The present study shows that the additional presentation of sounds with manipulated timings could help to determine the perceived direction of tactile motion despite the ambiguity in the interpretation of tactile stimuli at ipsilateral locations. Furthermore, we found that there is a limited alternation rate for tactile stimuli that can be used to achieve significant modulation using sound. We relate the temporal properties observed during crossmodal effects in tactile motion perception, to those observed during some other crossmodal phenomena.

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

    Science.gov (United States)

    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. © 2015 Wiley Periodicals, Inc.

  16. Block randomization versus complete randomization of human perception stimuli: is there a difference?

    Science.gov (United States)

    Moyer, Steve; Uhl, Elizabeth R.

    2015-05-01

    For more than 50 years, the U.S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) has been studying and modeling the human visual discrimination process as it pertains to military imaging systems. In order to develop sensor performance models, human observers are trained to expert levels in the identification of military vehicles. From 1998 until 2006, the experimental stimuli were block randomized, meaning that stimuli with similar difficulty levels (for example, in terms of distance from target, blur, noise, etc.) were presented together in blocks of approximately 24 images but the order of images within the block was random. Starting in 2006, complete randomization came into vogue, meaning that difficulty could change image to image. It was thought that this would provide a more statistically robust result. In this study we investigated the impact of the two types of randomization on performance in two groups of observers matched for skill to create equivalent groups. It is hypothesized that Soldiers in the Complete Randomized condition will have to shift their decision criterion more frequently than Soldiers in the Block Randomization group and this shifting is expected to impede performance so that Soldiers in the Block Randomized group perform better.

  17. Neurocognitive correlates of processing food-related stimuli in a Go/No-go paradigm.

    Science.gov (United States)

    Watson, Todd D; Garvey, Katherine T

    2013-12-01

    We examined the neurocognitive correlates of processing food-related stimuli in healthy young adults. Event-related potential (ERP) data were collected while 48 participants completed a computerized Go/No-go task consisting of food and nonfood images. Separately, we assessed participants' self-reported levels of external, restrained, and emotional eating behaviors as well as trait impulsivity, behavioral activation/inhibition, and performance on the Stroop Color-Word Test. We found that across participants, food images elicited significantly enhanced P3(00) and slow-wave ERP components. The difference in slow-wave components elicited by food and nonfood images was correlated with Stroop interference scores. Food images also elicited significantly enhanced N2(00) components, but only in female participants. The difference between N2 components elicited by food and nonfood images was related to body mass index and scores of external eating in females. Overall, these data suggest that processing food-related stimuli recruits distinct patterns of cortical activity, that the magnitude of these effects is related to behavioral and cognitive variables, and that the neurocognitive correlates of processing food-cues may be at least partly dissociable between males and females.

  18. How Attention Modulates Encoding of Dynamic Stimuli

    Science.gov (United States)

    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

  19. Dynamic bioactive stimuli-responsive polymeric surfaces

    Science.gov (United States)

    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 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. This was accomplished by carbodiimide coupling between --COOH

  20. [Imaging].

    Science.gov (United States)

    Chevrot, A; Drapé, J L; Godefroy, D; Dupont, A M; Pessis, E; Sarazin, L; Minoui, A

    1997-01-01

    The panoply of imaging techniques useful in podology is essentially limited to X-rays. Standard "standing" and "lying" X-rays furnish most of the required information. Arthrography is sometimes performed, in particular for trauma or tumour of the ankle. CT scan and MRI make a decisive contribution in difficult cases, notably in fractures and in small fractures without displacement. The two latter techniques are useful in tendon, ligament and muscular disorders, where echography is also informative. Rigorous analysis of radiographies and a good knowledge of foot disorders make these imaging techniques efficacious.

  1. The Presentation of Olfactory-Trigeminal Mixed Stimuli Increases the Response to Subsequent Olfactory Stimuli.

    Science.gov (United States)

    Walliczek-Dworschak, Ute; Poncelet, Johan; Baum, Daniel; Baki, Ramona; Sinding, Charlotte; Warr, Jonathan; Hummel, Thomas

    2017-01-09

    The aim of this study was to evaluate the effect of (1) the addition of trigeminal stimuli to an olfactory stimulus and (2) the congruence in the odorous mixture after repeated odor presentation. Twenty-five normosmic volunteers were enrolled and presented stimulation blocks, consisting of three habituation stimuli (H) (orange odor), one dishabituation (DH) (control condition, orange odor; congruent condition, orange odor + CO2; incongruent condition, orange odor + l-isopulegol), and one dishabituated stimulus (D) (orange odor). Olfactory event-related potentials were analyzed. Response amplitudes differed significantly in the incongruent condition (N1P2 between H3 and D; peak to peak N1P2 at electrode positions Cz, Fz, and Pz; response amplitudes between H3 and DH). The addition of CO2 modified the perception of orange odor, pronouncing a fruity note, whereas the addition of l-isopulegol as a DH pronounced the l-isopulegol note. This study provides evidence that incongruent trigeminal-olfactory stimulants increase the response to subsequent olfactory stimulus.

  2. Perceptual Sensitivity and Response to Strong Stimuli Are Related

    Directory of Open Access Journals (Sweden)

    Anna C. Bolders

    2017-09-01

    Full Text Available To shed new light on the long-standing debate about the (independence of sensitivity to weak stimuli and overreactivity to strong stimuli, we examined the relation between these tendencies within the neurobehavioral framework of the Predictive and Reactive Control Systems (PARCS theory (Tops et al., 2010, 2014. Whereas previous studies only considered overreactivity in terms of the individual tendency to experience unpleasant affect (punishment reactivity resulting from strong sensory stimulation, we also took the individual tendency to experience pleasant affect (reward reactivity resulting from strong sensory stimulation into account. According to PARCS theory, these temperamental tendencies overlap in terms of high reactivity toward stimulation, but oppose each other in terms of the response orientation (approach or avoid. PARCS theory predicts that both types of reactivity to strong stimuli relate to sensitivity to weak stimuli, but that these relationships are suppressed due to the opposing relationship between reward and punishment reactivity. We measured punishment and reward reactivity to strong stimuli and sensitivity to weak stimuli using scales from the Adult Temperament Questionnaire (Evans and Rothbart, 2007. Sensitivity was also measured more objectively using the masked auditory threshold. We found that sensitivity to weak stimuli (both self-reported and objectively assessed was positively associated with self-reported punishment and reward reactivity to strong stimuli, but only when these reactivity measures were controlled for each other, implicating a mutual suppression effect. These results are in line with PARCS theory and suggest that sensitivity to weak stimuli and overreactivity are dependent, but this dependency is likely to be obscured if punishment and reward reactivity are not both taken into account.

  3. Neuronal Representation of Ultraviolet Visual Stimuli in Mouse Primary Visual Cortex

    Science.gov (United States)

    Tan, Zhongchao; Sun, Wenzhi; Chen, Tsai-Wen; Kim, Douglas; Ji, Na

    2015-01-01

    The mouse has become an important model for understanding the neural basis of visual perception. Although it has long been known that mouse lens transmits ultraviolet (UV) light and mouse opsins have absorption in the UV band, little is known about how UV visual information is processed in the mouse brain. Using a custom UV stimulation system and in vivo calcium imaging, we characterized the feature selectivity of layer 2/3 neurons in mouse primary visual cortex (V1). In adult mice, a comparable percentage of the neuronal population responds to UV and visible stimuli, with similar pattern selectivity and receptive field properties. In young mice, the orientation selectivity for UV stimuli increased steadily during development, but not direction selectivity. Our results suggest that, by expanding the spectral window through which the mouse can acquire visual information, UV sensitivity provides an important component for mouse vision. PMID:26219604

  4. External-stimuli responsive systems for cancer theranostic

    Directory of Open Access Journals (Sweden)

    Jianhui Yao

    2016-10-01

    Full Text Available The upsurge of novel nanomaterials and nanotechnologies has inspired the researchers who are striving for designing safer and more efficient drug delivery systems for cancer therapy. Stimuli responsive nanomaterial offered an alternative to design controllable drug delivery system on account of its spatiotemporally controllable properties. Additionally, external stimuli (light, magnetic field and ultrasound could develop into theranostic applications for personalized medicine use because of their unique characteristics. In this review, we give a brief overview about the significant progresses and challenges of certain external-stimuli responsive systems that have been extensively investigated in drug delivery and theranostics within the last few years.

  5. Response properties of cat AMLS neurons to optic flow stimuli

    Institute of Scientific and Technical Information of China (English)

    LI; Baowang(李宝旺); LI; Bing(李兵); CHEN; Hui(陈辉); XU; Ying(徐颖); DIAO; Yuncheng(刁云程)

    2002-01-01

    Spiral and translation stimuli were used to investigate the response properties of cat AMLS (anteromedial lateral suprasylvian area) neurons to optic flow. The overwhelming majority of cells could be significantly excited by the two modes of stimuli and most responsive cells displayed obvious direction selectivity. It is the first time to find a visual area in mammalian brain preferring rotation stimuli. Two representative hypotheses are discussed here on the neural mechanism of optic flow analysis in visual cortex, and some new viewpoints are proposed to explain the experimental results.

  6. Do mirror glasses have the same effect on brain activity as a mirror box? Evidence from a functional magnetic resonance imaging study with healthy subjects.

    Science.gov (United States)

    Milde, Christopher; Rance, Mariela; Kirsch, Pinar; Trojan, Jörg; Fuchs, Xaver; Foell, Jens; Bekrater-Bodmann, Robin; Flor, Herta; Diers, Martin

    2015-01-01

    Since its original proposal, mirror therapy has been established as a successful neurorehabilitative intervention in several neurological disorders to recover motor function or to relieve pain. Mirror therapy seems to operate by reactivating the contralesional representation of the non-mirrored limb in primary motor- and somatosensory cortex. However, mirror boxes have some limitations which prompted the use of additional mirror visual feedback devices. The present study evaluated the utility of mirror glasses compared to a mirror box. We also tested the hypothesis that increased interhemispheric communication between the motor hand areas is the mechanism by which mirror visual feedback recruits the representation of the non-mirrored limb. Therefore, mirror illusion capacity and brain activations were measured in a within-subject design during both mirror visual feedback conditions in counterbalanced order with 20 healthy subjects inside a magnetic resonance imaging scanner. Furthermore, we analyzed task-dependent functional connectivity between motor hand representations using psychophysiological interaction analysis during both mirror tasks. Neither the subjective quality of mirror illusions nor the patterns of functional brain activation differed between the mirror tasks. The sensorimotor representation of the non-mirrored hand was recruited in both mirror tasks. However, a significant increase in interhemispheric connectivity between the hand areas was only observed in the mirror glasses condition, suggesting different mechanisms for the recruitment of the representation of the non-mirrored hand in the two mirror tasks. We conclude that the mirror glasses might be a promising alternative to the mirror box, as they induce similar patterns of brain activation. Moreover, the mirror glasses can be easy applied in therapy and research. We want to emphasize that the neuronal mechanisms for the recruitment of the affected limb representation might differ depending on

  7. Selective inattention to anxiety-linked stimuli.

    Science.gov (United States)

    Blum, G S; Barbour, J S

    1979-06-01

    prior hypnotic programming of the same three subjects was similar to Experiment 1, used an anagram approach to comparable four-letter words, except that pleasure-loaded words were introduced as a control along with filler words. Four durations of tachistoscopic exposure of the anagrams were used with each individual, and the major dependent variable was response latency measured in milliseconds. An independent measure of perceptual discriminability of the scrambled stimulus letters was obtained to isolate perceptual from cognitive aspects of the task. The results indicated that both low perceivability and high solvability increase the likelihood of response delays specifically in the presence of anxiety-linked stimuli. Experiment 3 was a nonhypnotic replication of Experiment 2, using 12 male and 13 female subjects. The potential affective loading of key anxiety and pleasure words was accomplished by structured scenarios for the Blacky pictures in which subjects were asked to place themselves as vividly as possible...

  8. Influence of worry on sustained attention to emotional stimuli: evidence from the late positive potential.

    Science.gov (United States)

    Burkhouse, Katie L; Woody, Mary L; Owens, Max; Gibb, Brandon E

    2015-02-19

    There is preliminary evidence to suggest that worry is associated with dysregulated emotion processing resulting from sustained attention to emotional versus neutral stimuli; however, this hypothesis has not been directly tested in prior research. Therefore, the current study used the event-related late positive potential (LPP) to directly examine if high levels of trait worry moderate sustained attention to emotional versus neutral stimuli. Electroencephalogram data was recorded while twenty-two women passively viewed neutral, positive, dysphoric, and threatening emotional images. Consistent with our hypotheses, higher levels of worry were associated with larger LPP amplitudes for emotional images but not neutral images. Importantly, the positive correlations between trait worry and LPP responses to threatening and positive images were maintained even when controlling for the influence of current anxiety symptoms, suggesting that worry may influence emotion processing whether or not the person is currently anxious. This sustained attention to emotional information may be one mechanism underlying how trait worry increases risk for anxiety disorders.

  9. Do extraverts process social stimuli differently from introverts?

    Science.gov (United States)

    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.

  10. Embodying approach motivation: body posture influences startle eyeblink and event-related potential responses to appetitive stimuli.

    Science.gov (United States)

    Price, Tom F; Dieckman, Laurtiz W; Harmon-Jones, Eddie

    2012-07-01

    Past research suggested that the motivational significance of images influences reflexive and electrocortical responses to those images (Briggs and Martin, 2009; Gard et al., 2007; Schupp et al., 2004), with erotica often exerting the largest effects for appetitive pictures (Grillon and Baas, 2003; Weinberg and Hajcak, 2010). This research paradigm, however, compares responses to different types of images (e.g., erotica vs. exciting sports scenes). This past motivational interpretation, therefore, would be further supported by experiments wherein appetitive picture content is held constant and motivational states are manipulated with a different method. In the present experiment, we tested the hypothesis that changes in physical postures associated with approach motivation influences reflexive and electrocortical responses to appetitive stimuli. Past research has suggested that bodily manipulations (e.g., facial expressions) play a role in emotion- and motivation-related physiology (Ekman and Davidson, 1993; Levenson et al., 1990). Extending these results, leaning forward (associated with a heightened urge to approach stimuli) relative to reclining (associated with less of an urge to approach stimuli) caused participants to have smaller startle eyeblink responses during appetitive, but not neutral, picture viewing. Leaning relative to reclining also caused participants to have larger LPPs to appetitive but not neutral pictures, and influenced ERPs as early as 100ms into stimulus viewing. This evidence suggests that body postures associated with approach motivation causally influence basic reflexive and electrocortical reactions to appetitive emotive stimuli. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Prefrontal cortex neurons reflect categorical decisions about ambiguous stimuli

    OpenAIRE

    Roy, Jefferson E.; Buschman, Timothy J.; Miller, Earl K

    2014-01-01

    We examined whether prefrontal cortex (PFC) neuron activity reflects categorical decisions in monkeys categorizing ambiguous stimuli. A morphing system was used to systematically vary stimulus shape and precisely define category boundaries. Ambiguous stimuli were centered on a category boundary, i.e., they were a mix of 50% of two prototypes and therefore had no category information, so monkeys guessed at their category membership. We found that the monkey's trial-by-trial decision about the ...

  12. Animation Stimuli System for Research on Instructor Gestures in Education.

    Science.gov (United States)

    Cui, Jian; Popescu, Voicu; Adamo-Villani, Nicoletta; Wagner Cook, Susan; Duggan, Katherine A; Friedman, Howard S

    2017-01-01

    Education research has shown that instructor gestures can help capture, maintain, and direct the student's attention during a lecture as well as enhance learning and retention. Traditional education research on instructor gestures relies on video stimuli, which are time consuming to produce, especially when gesture precision and consistency across conditions are strictly enforced. The proposed system allows users to efficiently create accurate and effective stimuli for complex studies on gesture, without the need for computer animation expertise or artist talent.

  13. Intersubject information mapping: revealing canonical representations of complex natural stimuli

    Directory of Open Access Journals (Sweden)

    Nikolaus Kriegeskorte

    2015-03-01

    Full Text Available Real-world time-continuous stimuli such as video promise greater naturalism for studies of brain function. However, modeling the stimulus variation is challenging and introduces a bias in favor of particular descriptive dimensions. Alternatively, we can look for brain regions whose signal is correlated between subjects, essentially using one subject to model another. Intersubject correlation mapping (ICM allows us to find brain regions driven in a canonical manner across subjects by a complex natural stimulus. However, it requires a direct voxel-to-voxel match between the spatiotemporal activity patterns and is thus only sensitive to common activations sufficiently extended to match up in Talairach space (or in an alternative, e.g. cortical-surface-based, common brain space. Here we introduce the more general approach of intersubject information mapping (IIM. For each brain region, IIM determines how much information is shared between the subjects' local spatiotemporal activity patterns. We estimate the intersubject mutual information using canonical correlation analysis applied to voxels within a spherical searchlight centered on each voxel in turn. The intersubject information estimate is invariant to linear transforms including spatial rearrangement of the voxels within the searchlight. This invariance to local encoding will be crucial in exploring fine-grained brain representations, which cannot be matched up in a common space and, more fundamentally, might be unique to each individual – like fingerprints. IIM yields a continuous brain map, which reflects intersubject information in fine-grained patterns. Performed on data from functional magnetic resonance imaging (fMRI of subjects viewing the same television show, IIM and ICM both highlighted sensory representations, including primary visual and auditory cortices. However, IIM revealed additional regions in higher association cortices, namely temporal pole and orbitofrontal cortex. These

  14. Bitter taste stimuli induce differential neural codes in mouse brain.

    Directory of Open Access Journals (Sweden)

    David M Wilson

    Full Text Available 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.

  15. The use of visual stimuli during auditory assessment.

    Science.gov (United States)

    Pearlman, R C; Cunningham, D R; Williamson, D G; Amerman, J D

    1975-01-01

    Two groups of male subjects beyond 50 years of age were given audiometric tasks with and without visual stimulation to determine if visual stimuli changed auditory perception. The first group consisted of 10 subjects with normal auditory acuity; the second, 10 with sensorineural hearing losses greater than 30 decibels. The rate of presentation of the visual stimuli, consisting of photographic slides of various subjects, was determined in experiment I of the study. The subjects, while viewing the slides at their own rate, took an audiotry speech discrimination test. Advisedly they changed the slides at a speed which they felt facilitated attention while performing the auditory task. The mean rate of slide-changing behavior was used as the "optimum" visual stimulation rate in experiment II, which was designed to explore the interaction of the bisensory presentation of stimuli. Bekesy tracings and Rush Hughes recordings were administered without and with visual stimuli, the latter presented at the mean rate of slide changes found in experiment I. Analysis of data indicated that (1) no statistically significant difference exists between visual and nonvisual conditions during speech discrimination and Bekesy testing; and (2) subjects did not believe that visual stimuli as presented in this study helped them to listen more effectively. The experimenter concluded that the various auditory stimuli encountered in the auditory test situation may actually be a deterrent to boredom because of the variety of tasks required in a testing situation.

  16. Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Kienast, Thorsten; Rapp, Michael [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Siessmeier, Thomas; Buchholz, Hans G.; Schreckenberger, Mathias [University of Mainz, Department of Nuclear Medicine, Mainz (Germany); Wrase, Jana; Heinz, Andreas [Charite Campus Mitte, Department of Psychiatry and Psychotherapy of the Charite University Medical Center, Berlin (Germany); Central Institute of Mental Health, Mannheim (Germany); Braus, Dieter F. [University of Hamburg, Neuroimage Nord, Department of Psychiatry, Hamburg (Germany); Smolka, Michael N.; Mann, Karl [Central Institute of Mental Health, Mannheim (Germany); Roesch, Frank [University of Mainz, Institute of Nuclear Chemistry, Mainz (Germany); Cumming, Paul [PET Center and Center for Functionally Integrative Neuroscience, Aarhus (Denmark); Gruender, Gerhard [Aachen University Medical Center, Department of Psychiatry of the RWTH, Mainz (Germany); Bartenstein, Peter [Ludwig-Maximilians-University, Department of Nuclear Medicine, Munich (Germany)

    2008-06-15

    Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. Subjects were investigated with positron emission tomography and [{sup 18}F]DOPA for measurements of dopamine synthesis capacity and [{sup 18}F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [{sup 18}F]DOPA net influx constant K{sub in}{sup app} /[{sup 18}F]DMFP-binding potential (BP{sub N}D) in the ventral and dorsal striatum. The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas. (orig.)

  17. Fishy fishes: the typicality of object stimuli used to assess children's language in the Reynell Development Language Scales--III.

    Science.gov (United States)

    Syrnyk, Corinne; Meints, Kerstin

    2012-01-01

    Numerous studies show clear evidence that children display typicality effects during early word learning. However, little is known of the typicality of stimuli used by standardized language tests to assess children's language development. To examine the typicality of stimuli used by the Reynell Developmental Language Scales-III (RDLS-III), a standardized language assessment that measures children's language abilities. Two sets of items were compared: RDLS-III items and a set of Matching items that had previously been judged to be highly typical exemplars. Experiment 1 asked adults to rate images of RDLS-III items and the set of Matching items for typicality; while Experiment 2 asked adults to choose the 'best exemplar' from these sets of items. Experiment 3 used Intermodal Preferential Looking (IPL) to examine 4-year-olds' looking behaviour towards both the RDLS-III items and Matching stimuli. In supplement of Experiment 3, Experiment 4 asked children to indicate the better exemplar using a forced-choice pointing method. Both adults and children preferred the Matching, more typical items. This is the first study to demonstrate that stimuli used for assessing early language development in the RDLS-III are not judged to be typical by children or adults. It highlights the differences in stimuli and discusses the potential consequences of stimulus choice in the assessment early language. © 2012 Royal College of Speech and Language Therapists.

  18. Alpha and gamma oscillation amplitudes synergistically predict the perception of forthcoming nociceptive stimuli.

    Science.gov (United States)

    Tu, Yiheng; Zhang, Zhiguo; Tan, Ao; Peng, Weiwei; Hung, Yeung Sam; Moayedi, Massieh; Iannetti, Gian Domenico; Hu, Li

    2016-02-01

    Ongoing fluctuations of intrinsic cortical networks determine the dynamic state of the brain, and influence the perception of forthcoming sensory inputs. The functional state of these networks is defined by the amplitude and phase of ongoing oscillations of neuronal populations at different frequencies. The contribution of functionally different cortical networks has yet to be elucidated, and only a clear dependence of sensory perception on prestimulus alpha oscillations has been clearly identified. Here, we combined electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) in a large sample of healthy participants to investigate how ongoing fluctuations in the activity of different cortical networks affect the perception of subsequent nociceptive stimuli. We observed that prestimulus EEG oscillations in the alpha (at bilateral central regions) and gamma (at parietal regions) bands negatively modulated the perception of subsequent stimuli. Combining information about alpha and gamma oscillations predicted subsequent perception significantly more accurately than either measure alone. In a parallel experiment, we found that prestimulus fMRI activity also modulated the perception of subsequent stimuli: perceptual ratings were higher when the BOLD signal was higher in nodes of the sensorimotor network and lower in nodes of the default mode network. Similar to what observed in the EEG data, prediction accuracy was improved when the amplitude of prestimulus BOLD signals in both networks was combined. These findings provide a comprehensive physiological basis to the idea that dynamic changes in brain state determine forthcoming behavioral outcomes. Hum Brain Mapp 37:501-514, 2016. © 2015 Wiley Periodicals, Inc.

  19. Effects of facial attractiveness on personality stimuli in an implicit priming task: an ERP study.

    Science.gov (United States)

    Zhang, Yan; Zheng, Minxiao; Wang, Xiaoying

    2016-08-01

    Using event-related potentials (ERPs) in a priming paradigm, this study examines implicit priming in the association of personality words with facial attractiveness. A total of 16 participants (8 males and 8 females; age range, 19-24 years; mean age, 21.30 years) were asked to judge the color (red and green) of positive or negative personality words after exposure to priming stimuli (attractive and unattractive facial images). The positive personality words primed by attractive faces or the negative personality words primed by unattractive faces were defined as congruent trials, whereas the positive personality words primed by unattractive faces or the negative personality words primed by attractive faces were defined as incongruent trials. Behavioral results showed that compared with the unattractive faces trials, the trials that attractive faces being the priming stimuli had longer reaction times and higher accuracy rates. Moreover, a more negative ERP deflection (N2) component was observed in the ERPs of the incongruent condition than in the ERPs of the congruent condition. In addition, the personality words presented after the attractive faces elicited larger amplitudes from the frontal region to the central region (P2 and P350-550 ms) compared with the personality words after unattractive faces as priming stimuli. The study provides evidence for the facial attractiveness stereotype ('What is beautiful is good') through an implicit priming task.

  20. Mid-adolescent neurocognitive development of ignoring and attending emotional stimuli.

    Science.gov (United States)

    Vetter, Nora C; Pilhatsch, Maximilian; Weigelt, Sarah; Ripke, Stephan; Smolka, Michael N

    2015-08-01

    Appropriate reactions toward emotional stimuli depend on the distribution of prefrontal attentional resources. In mid-adolescence, prefrontal top-down control systems are less engaged, while subcortical bottom-up emotional systems are more engaged. We used functional magnetic resonance imaging to follow the neural development of attentional distribution, i.e. attending versus ignoring emotional stimuli, in adolescence. 144 healthy adolescents were studied longitudinally at age 14 and 16 while performing a perceptual discrimination task. Participants viewed two pairs of stimuli--one emotional, one abstract--and reported on one pair whether the items were the same or different, while ignoring the other pair. Hence, two experimental conditions were created: "attending emotion/ignoring abstract" and "ignoring emotion/attending abstract". Emotional valence varied between negative, positive, and neutral. Across conditions, reaction times and error rates decreased and activation in the anterior cingulate and inferior frontal gyrus increased from age 14 to 16. In contrast, subcortical regions showed no developmental effect. Activation of the anterior insula increased across ages for attending positive and ignoring negative emotions. Results suggest an ongoing development of prefrontal top-down resources elicited by emotional attention from age 14 to 16 while activity of subcortical regions representing bottom-up processing remains stable.

  1. Perception of social stimuli in mania: an fMRI study.

    Science.gov (United States)

    Usnich, Tatiana; Spengler, Stephanie; Sajonz, Bastian; Herold, Dorrit; Bauer, Michael; Bermpohl, Felix

    2015-01-30

    Patients with mania show alterations of social behaviour. Neuropsychological studies in euthymic bipolar disorder (BD) have revealed deficits in cognitive, but not emotional aspects of social cognition (SC). Here, we studied the neural signature of social stimulus processing in mania. We expected alterations in regions associated with cognitive SC (dorsal-medial prefrontal cortex, dMPFC). Participants comprised 14 manic patients and 14 matched healthy controls who viewed standardized pictures with social and non-social content during functional magnetic resonance imaging (fMRI). Region-of-interest-analyses focused on areas related to SC (dorsal/ventral medial prefrontal cortex; temporo-parietal junction), determined by a quantitative meta-analysis. Between-group comparisons ('social>non-social') revealed reduced BOLD responses in the right dMPFC in manic patients, but no significant group difference in the ventral MPFC. In addition, manic patients showed elevated BOLD activation in the right temporo-parietal junction during perception of social stimuli, which was correlated with increased delusional ideation. Patients with mania show diminished BOLD responses to social stimuli in the right dMPFC, associated with cognitive SC and this may be related to reported deficits in understanding others' mental states. At the same time, manic patients show hyperactivation of the right temporo-parietal junction, likely related to exaggerated attribution of meaning to social stimuli. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Brain activation by visual erotic stimuli in healthy middle aged males.

    Science.gov (United States)

    Kim, S W; Sohn, D W; Cho, Y-H; Yang, W S; Lee, K-U; Juh, R; Ahn, K-J; Chung, Y-A; Han, S-I; Lee, K H; Lee, C U; Chae, J-H

    2006-01-01

    The objective of the present study was to identify brain centers, whose activity changes are related to erotic visual stimuli in healthy, heterosexual, middle aged males. Ten heterosexual, right-handed males with normal sexual function were entered into the present study (mean age 52 years, range 46-55). All potential subjects were screened over 1 h interview, and were encouraged to fill out questionnaires including the Brief Male Sexual Function Inventory. All subjects with a history of sexual arousal disorder or erectile dysfunction were excluded. We performed functional brain magnetic resonance imaging (fMRI) in male volunteers when an alternatively combined erotic and nonerotic film was played for 14 min and 9 s. The major areas of activation associated with sexual arousal to visual stimuli were occipitotemporal area, anterior cingulate gyrus, insula, orbitofrontal cortex, caudate nucleus. However, hypothalamus and thalamus were not activated. We suggest that the nonactivation of hypothalamus and thalamus in middle aged males may be responsible for the lesser physiological arousal in response to the erotic visual stimuli.

  3. Mid-adolescent neurocognitive development of ignoring and attending emotional stimuli

    Directory of Open Access Journals (Sweden)

    Nora C. Vetter

    2015-08-01

    Full Text Available Appropriate reactions toward emotional stimuli depend on the distribution of prefrontal attentional resources. In mid-adolescence, prefrontal top-down control systems are less engaged, while subcortical bottom-up emotional systems are more engaged. We used functional magnetic resonance imaging to follow the neural development of attentional distribution, i.e. attending versus ignoring emotional stimuli, in adolescence. 144 healthy adolescents were studied longitudinally at age 14 and 16 while performing a perceptual discrimination task. Participants viewed two pairs of stimuli – one emotional, one abstract – and reported on one pair whether the items were the same or different, while ignoring the other pair. Hence, two experimental conditions were created: “attending emotion/ignoring abstract” and “ignoring emotion/attending abstract”. Emotional valence varied between negative, positive, and neutral. Across conditions, reaction times and error rates decreased and activation in the anterior cingulate and inferior frontal gyrus increased from age 14 to 16. In contrast, subcortical regions showed no developmental effect. Activation of the anterior insula increased across ages for attending positive and ignoring negative emotions. Results suggest an ongoing development of prefrontal top-down resources elicited by emotional attention from age 14 to 16 while activity of subcortical regions representing bottom-up processing remains stable.

  4. Sex-related memory recall and talkativeness for emotional stimuli

    Directory of Open Access Journals (Sweden)

    Benedetto eArnone

    2011-09-01

    Full Text Available Recent studies have evidenced an increasing interest in sex-related brain mechanisms and cerebral lateralization subserving emotional memory, language processing, and conversational behavior. We used event related potentials (ERP to examine the influence of sex and hemisphere on brain responses to emotional stimuli. Given that the P300 component of ERP is considered a cognitive neuroelectric phenomenon, we compared left and right hemisphere P300 responses to emotional stimuli in men and women. As indexed by both amplitude and latency measures, emotional stimuli elicited more robust P300 effects in the left hemisphere in women than in men, while a stronger P300 component was elicited in the right hemisphere in men compared to women. Our findings show that the variables of sex and hemisphere interacted significantly to influence the strength of the P300 component to the emotional stimuli. Emotional stimuli were also best recalled when given a long-term, incidental memory test, a fact potentially related to the differential P300 waves at encoding. Moreover, taking into account the sex-related differences in language processing and conversational behaviour, in the present study we evaluated possible talkativeness differences between the two genders in the recollection of emotional stimuli. Our data showed that women used a higher number of words, compared to men, to describe both arousal and neutral stories. Moreover, the present results support the view that sex differences in lateralization may not be a general feature of language processing but may be related to the specific condition, such as the emotional content of stimuli.

  5. Sex-related memory recall and talkativeness for emotional stimuli.

    Science.gov (United States)

    Arnone, Benedetto; Pompili, Assunta; Tavares, Maria Clotilde; Gasbarri, Antonella

    2011-01-01

    Recent studies have evidenced an increasing interest in sex-related brain mechanisms and cerebral lateralization subserving emotional memory, language processing, and conversational behavior. We used event-related-potentials (ERP) to examine the influence of sex and hemisphere on brain responses to emotional stimuli. Given that the P300 component of ERP is considered a cognitive neuroelectric phenomenon, we compared left and right hemisphere P300 responses to emotional stimuli in men and women. As indexed by both amplitude and latency measures, emotional stimuli elicited more robust P300 effects in the left hemisphere in women than in men, while a stronger P300 component was elicited in the right hemisphere in men compared to women. Our findings show that the variables of sex and hemisphere interacted significantly to influence the strength of the P300 component to the emotional stimuli. Emotional stimuli were also best recalled when given a long-term, incidental memory test, a fact potentially related to the differential P300 waves at encoding. Moreover, taking into account the sex-related differences in language processing and conversational behavior, in the present study we evaluated possible talkativeness differences between the two genders in the recollection of emotional stimuli. Our data showed that women used a higher number of words, compared to men, to describe both arousal and neutral stories. Moreover, the present results support the view that sex differences in lateralization may not be a general feature of language processing but may be related to the specific condition, such as the emotional content of stimuli.

  6. Who is afraid of the invisible snake? Subjective visual awareness modulates posterior brain activity for evolutionarily threatening stimuli.

    Science.gov (United States)

    Grassini, Simone; Holm, Suvi K; Railo, Henry; Koivisto, Mika

    2016-12-01

    Snakes were probably one of the earliest predators of primates, and snake images produce specific behavioral and electrophysiological reactions in humans. Pictures of snakes evoke enhanced activity over the occipital cortex, indexed by the "early posterior negativity" (EPN), as compared with pictures of other dangerous or non-dangerous animals. The present study investigated the possibility that the response to snake images is independent from visual awareness. The observers watched images of threatening and non-threatening animals presented in random order during rapid serial visual presentation. Four different masking conditions were used to manipulate awareness of the images. Electrophysiological results showed that the EPN was larger for snake images than for the other images employed in the unmasked condition. However, the difference disappeared when awareness of the stimuli decreased. Behavioral results on the effects of awareness did not show any advantage for snake images. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Stimuli-Responsive Materials for Controlled Release Applications

    KAUST Repository

    Li, Song

    2015-04-01

    The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. To address this outstanding problem, the design and fabrication of stimuli-responsive materials are pursued to guarantee the controlled release of cargo at a specific time and with an accurate amount. Upon applying different stimuli such as light, magnetic field, heat, pH change, enzymes or redox, functional materials change their physicochemical properties through physical transformation or chemical reactions, allowing the release of payload agents on demand. This dissertation studied three stimuli-responsive membrane systems for controlled release from films of macro sizes to microcapsules of nano sizes. The first membrane system is a polymeric composite film which can decrease and sustain diffusion upon light irradiation. The photo-response of membranes is based on the photoreaction of cinnamic derivatives. The second one is composite membrane which can improve diffusion upon heating. The thermo-response of membranes comes from the volume phase transition ability of hydrogels. The third one is microcapsule which can release encapsulated agents upon light irradiation. The photo-response of capsules results from the photoreaction of nitrobenzyl derivatives. The study on these membrane systems reveals that stimuli-responsive release can be achieved by utilizing different functional materials on either macro or micro level. Based on the abundant family of smart materials, designing and fabricating stimuli-responsive systems shall lead to various advanced release processes on demand for biomedical applications.

  8. Protein-surface interactions on stimuli-responsive polymeric biomaterials.

    Science.gov (United States)

    Cross, Michael C; Toomey, Ryan G; Gallant, Nathan D

    2016-03-04

    Responsive surfaces: a review of the dependence of protein adsorption on the reversible volume phase transition in stimuli-responsive polymers. Specifically addressed are a widely studied subset: thermoresponsive polymers. Findings are also generalizable to other materials which undergo a similarly reversible volume phase transition. As of 2015, over 100,000 articles have been published on stimuli-responsive polymers and many more on protein-biomaterial interactions. Significantly, fewer than 100 of these have focused specifically on protein interactions with stimuli-responsive polymers. These report a clear trend of increased protein adsorption in the collapsed state compared to the swollen state. This control over protein interactions makes stimuli-responsive polymers highly useful in biomedical applications such as wound repair scaffolds, on-demand drug delivery, and antifouling surfaces. Outstanding questions are whether the protein adsorption is reversible with the volume phase transition and whether there is a time-dependence. A clear understanding of protein interactions with stimuli-responsive polymers will advance theoretical models, experimental results, and biomedical applications.

  9. P1-32: Response of Human Visual System to Paranormal Stimuli Appearing in Three-Dimensional Display

    Directory of Open Access Journals (Sweden)

    Jisoo Hong

    2012-10-01

    Full Text Available Three-dimensional (3D display became one of indispensable features of commercial TVs in recent years. However, the 3D content displayed by 3D display may contain the abrupt change of depth when the scene changes, which might be considered as a paranormal stimulus. Because the human visual system is not accustomed to such paranormal stimuli in natural conditions, they can cause unexpected responses which usually induce discomfort. Following the change of depth expressed by 3D display, the eyeballs rotate to match the convergence to the new 3D image position. The amount of rotation varies according to the initial longitudinal location and depth displacement of 3D image. Because the change of depth is abrupt, there is delay in human visual system following the change and such delay can be a source of discomfort. To guarantee the safety in watching 3D TV, the acceptable level of displacement in the longitudinal direction should be revealed quantitatively. Additionally, the artificially generated scenes also can provide paranormal stimuli such as periodic depth variations. In the presentation, we investigate the response of human visual system to such paranormal stimuli given by 3D display system. Using the result of investigation, we can give guideline to creating the 3D content to minimize the discomfort coming from the paranormal stimuli.

  10. Response of biomembrane domains to external stimuli

    Science.gov (United States)

    Urbancic, Iztok

    To enrich our knowledge about membrane domains, new measurement techniques with extended spatial and temporal windows are being vigorously developed by combining various approaches. Following such efforts of the scientific community, we set up fluorescence microspectroscopy (FMS), bridging two well established methods: fluorescence microscopy, which enables imaging of the samples with spatial resolution down to 200 nm, and fluorescence spectroscopy that provides molecular information of the environment at nanometer and nanosecond scale. The combined method therefore allows us to localize this type of information with the precision suitable for studying various cellular structures. Faced with weak available fluorescence signals, we have put considerable efforts into optimization of measurement processes and analysis of the data. By introducing a novel acquisition scheme and by fitting the data with a mathematical model, we preserved the spectral resolution, characteristic for spectroscopic measurements of bulk samples, also at microscopic level. We have at the same time overcome the effects of photobleaching, which had previously considerably distorted the measured spectral lineshape of photosensitive dyes and consequently hindered the reliability of FMS. Our new approach has therefore greatly extended the range of applicable environmentally sensitive probes, which can now be designed to better accommodate the needs of each particular experiment. Moreover, photobleaching of fluorescence signal can now even be exploited to obtain new valuable information about molecular environment of the probes, as bleaching rates of certain probes also depend on physical and chemical properties of the local surroundings. In this manner we increased the number of available spatially localized spectral parameters, which becomes invaluable when investigating complex biological systems that can only be adequately characterized by several independent variables. Applying the developed

  11. Intuitively detecting what is hidden within a visual mask: familiar-novel discrimination and threat detection for unidentified stimuli.

    Science.gov (United States)

    Cleary, Anne M; Ryals, Anthony J; Nomi, Jason S

    2013-10-01

    Recognition without identification is the finding that, among recognition test items that go unidentified (as when a word is unidentified from a fragment), participants can discriminate those that were studied from those that were unstudied. In the present study, we extended this phenomenon to the more life-like situation of discriminating known from novel stimuli. Pictures of famous and nonfamous faces (Exp. 1), famous and nonfamous scenes (Exp. 2), and threatening and nonthreatening images (Exp. 3) were filtered in order to impede identification. As in list-learning recognition-without-identification paradigms, participants attempted to identify each image (e.g., whose face it was, what scene it was, or what was in the picture) and rated how familiar the image seemed on a scale of 0 (very unfamiliar) to 10 (very familiar). Among the unidentified stimuli, higher familiarity ratings were given to famous than to nonfamous faces (Exp. 1) and scenes (Exp. 2), and to threatening than to nonthreatening living/animate (but not to nonliving/nonanimate) images (Exp. 3). These findings suggest that even when a stimulus is too occluded to allow for conscious identification, enough information can be processed to allow a sense of familiarity or novelty with it, which appears also to be related to the sense of whether or not a living creature is a threat. That the sense of familiarity for unidentified stimuli may be related to threat detection for living or animate things suggests that it may be an adaptive aspect of human memory.

  12. Behavioral detection of passive whisker stimuli requires somatosensory cortex.

    Science.gov (United States)

    Miyashita, Toshio; Feldman, Daniel E

    2013-07-01

    Rodent whisker sensation occurs both actively, as whiskers move rhythmically across objects, and in a passive mode in which externally applied deflections are sensed by static, non-moving whiskers. Passive whisker stimuli are robustly encoded in the somatosensory (S1) cortex, and provide a potentially powerful means of studying cortical processing. However, whether S1 contributes to passive sensation is debated. We developed 2 new behavioral tasks to assay passive whisker sensation in freely moving rats: Detection of unilateral whisker deflections and discrimination of right versus left whisker deflections. Stimuli were simple, simultaneous multi-whisker deflections. Local muscimol inactivation of S1 reversibly and robustly abolished sensory performance on these tasks. Thus, S1 is required for the detection and discrimination of simple stimuli by passive whiskers, in addition to its known role in active whisker sensation.

  13. Attentional capture by social stimuli in young infants

    Directory of Open Access Journals (Sweden)

    Maxie eGluckman

    2013-08-01

    Full Text Available We investigated the possibility that a range of social stimuli capture the attention of 6-month-old infants when in competition with other non-face objects. Infants viewed a series of six-item arrays in which one target item was a face, body part, or animal as their eye movements were recorded. Stimulus arrays were also processed for relative salience of each item in terms of color, luminance, and amount of contour. Targets were rarely the most visually salient items in the arrays, yet infants’ first looks toward all three target types were above chance, and dwell times for targets exceeded other stimulus types. Girls looked longer at faces than did boys, but there were no sex differences for other stimuli. These results are interpreted in a context of learning to discriminate between different classes of animate stimuli, perhaps in line with affordances for social interaction, and origins of sex differences in social attention.

  14. Pedophilic brain potential responses to adult erotic stimuli.

    Science.gov (United States)

    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.

  15. Response to various periods of mechanical stimuli in Physarum plasmodium

    Science.gov (United States)

    Umedachi, Takuya; Ito, Kentaro; Kobayashi, Ryo; Ishiguro, Akio; Nakagaki, Toshiyuki

    2017-06-01

    Response to mechanical stimuli is a fundamental and critical ability for living cells to survive in hazardous conditions or to form adaptive and functional structures against force(s) from the environment. Although this ability has been extensively studied by molecular biology strategies, it is also important to investigate the ability from the viewpoint of biological rhythm phenomena so as to reveal the mechanisms that underlie these phenomena. Here, we use the plasmodium of the true slime mold Physarum polycephalum as the experimental system for investigating this ability. The plasmodium was repetitively stretched for various periods during which its locomotion speed was observed. Since the plasmodium has inherent oscillation cycles of protoplasmic streaming and thickness variation, how the plasmodium responds to various periods of external stretching stimuli can shed light on the other biological rhythm phenomena. The experimental results show that the plasmodium exhibits response to periodic mechanical stimulation and changes its locomotion speed depending on the period of the stretching stimuli.

  16. Diffusion Based Modeling of Human Brain Response to External Stimuli

    CERN Document Server

    Namazi, Hamidreza

    2012-01-01

    Human brain response is the overall ability of the brain in analyzing internal and external stimuli in the form of transferred energy to the mind/brain phase-space and thus, making the proper decisions. During the last decade scientists discovered about this phenomenon and proposed some models based on computational, biological, or neuropsychological methods. Despite some advances in studies related to this area of the brain research there was less effort which have been done on the mathematical modeling of the human brain response to external stimuli. This research is devoted to the modeling of human EEG signal, as an alert state of overall human brain activity monitoring, due to receiving external stimuli, based on fractional diffusion equation. The results of this modeling show very good agreement with the real human EEG signal and thus, this model can be used as a strong representative of the human brain activity.

  17. Electrotactile stimuli delivered across fingertips inducing the Cutaneous Rabbit Effect.

    Science.gov (United States)

    Warren, Jay P; Santello, Marco; Helms Tillery, Stephen I

    2010-10-01

    Previous studies have been unable to induce the Cutaneous Rabbit Effect (CRE) when the most likely perceived location of the illusory stimulus is on a non-continuous skin area. To determine whether the CRE could be elicited when each of the delivered stimuli were on non-continuous skin areas, we developed a new electrotactile stimulation paradigm attempting to induce the CRE across the fingertips. Though our stimulation paradigm differed from classic reduced CRE paradigms through the use of electrotactile stimuli, focusing the subject attention to a 'likely' illusory site, and the inclusion of a fourth stimulation site (two stimuli after the illusory stimulus), these factors were not the cause of the illusory effect we observed. Experiments conducted on the forearm validated that our paradigm elicited similar results to those reported in previous CRE studies that used either 3-stimulation-point mechanical or electrotactile stimuli with subject attention focused on the 'likely' illusory site. Across the fingertips, we observed an increase in stimulus mislocalization onto the middle fingertip, the 'likely' perceived location of the illusory stimuli, under Illusory Rabbit Trains compared to the Motion Bias Trains. Because the Motion Bias Trains should not induce a perceived location shift of the illusory stimulus but stimulates the adjacent digits in a similar way to the Illusory Rabbit Trains, differences observed between their mislocalization rates between these trains indicate that the CRE can be induced across the fingertips. These results provide the first evidence that the CRE can 'jump' when the stimuli occur across non-continuous skin areas.

  18. A comparison of vernier acuity for narrowband and broadband stimuli.

    Science.gov (United States)

    Barrett, Brendan T; Whitaker, David

    2004-01-01

    This study investigates the influence of contrast and exposure duration on vernier acuity thresholds for abutting and separated narrowband stimuli, and asks whether these data can predict broadband vernier performance. Vernier thresholds were determined for sinusoidal grating stimuli at two spatial frequencies (1 and 8 c/deg) across a range of contrasts (0.05-0.8) and exposure durations (35-2100 ms). Performance was assessed for the abutting configuration, and when a gap equivalent to 0.5 to 1.5 times the spatial period of the grating was introduced between the upper and lower halves of the grating. Vernier thresholds were also determined for a square-wave stimulus as a function of contrast (0.06 to 0.78). Exposure duration was fixed at 2100 ms. In addition, thresholds were determined at the appropriate contrast levels for the fundamental frequency (1.8 c/deg) of the square-wave, and for a number of the harmonics (3F, 5F, 7F, 9F). Our results provide support for filter models of vernier acuity by showing that vernier performance for abutting and closely-separated broadband stimuli represents the envelope of vernier sensitivity of those spatial frequency mechanisms that are activated by the broadband stimulus. In the case of high frequency grating stimuli presented for long exposure durations, vernier performance can be invariant across much of the contrast range. Despite this, however, contrast independence is not exhibited for abutting broadband stimuli because, within the broadband stimuli, the contrast of the higher harmonic components never reaches a level to reveal this plateau.

  19. Joint attention for stimuli on the hands: Ownership matters

    OpenAIRE

    Eric eTaylor; Jay ePratt; Jessica eWitt

    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 on...

  20. Precuneus-prefrontal activity during awareness of visual verbal stimuli

    DEFF Research Database (Denmark)

    Kjaer, T W; Nowak, M; Kjær, Klaus Wilbrandt

    2001-01-01

    Awareness is a personal experience, which is only accessible to the rest of world through interpretation. We set out to identify a neural correlate of visual awareness, using brief subliminal and supraliminal verbal stimuli while measuring cerebral blood flow distribution with H(2)(15)O PET....... Awareness of visual verbal stimuli differentially activated medial parietal association cortex (precuneus), which is a polymodal sensory cortex, and dorsolateral prefrontal cortex, which is thought to be primarily executive. Our results suggest participation of these higher order perceptual and executive...... cortical structures in visual verbal awareness....

  1. Thermo-Responsive Hydrogels for Stimuli-Responsive Membranes

    Directory of Open Access Journals (Sweden)

    Evan Mah

    2013-09-01

    Full Text Available Composite membranes with stimuli-responsive properties can be made by coating a thermo-responsive hydrogel onto a micro- or macroporous support. These hydrogels undergo a temperature induced volume-phase transition, which contributes towards the composite membrane’s stimuli-responsive properties. This paper reviews research done on complimentary forms of temperature responsive “thermophilic” hydrogels, those exhibiting positive volume-phase transitions in aqueous solvent. The influences of intermolecular forces on the mechanism of phase-transition are discussed along with case examples of typical thermophilic hydrogels.

  2. The influence of motion quality on responses towards video playback stimuli

    Directory of Open Access Journals (Sweden)

    Emma Ware

    2015-07-01

    Full Text Available Visual motion, a critical cue in communication, can be manipulated and studied using video playback methods. A primary concern for the video playback researcher is the degree to which objects presented on video appear natural to the non-human subject. Here we argue that the quality of motion cues on video, as determined by the video's image presentation rate (IPR, are of particular importance in determining a subject's social response behaviour. We present an experiment testing the effect of variations in IPR on pigeon (Columbia livia response behaviour towards video images of courting opposite sex partners. Male and female pigeons were presented with three video playback stimuli, each containing a different social partner. Each stimulus was then modified to appear at one of three IPRs: 15, 30 or 60 progressive (p frames per second. The results showed that courtship behaviour became significantly longer in duration as IPR increased. This finding implies that the IPR significantly affects the perceived quality of motion cues impacting social behaviour. In males we found that the duration of courtship also depended on the social partner viewed and that this effect interacted with the effects of IPR on behaviour. Specifically, the effect of social partner reached statistical significance only when the stimuli were displayed at 60 p, demonstrating the potential for erroneous results when insufficient IPRs are used. In addition to demonstrating the importance of IPR in video playback experiments, these findings help to highlight and describe the role of visual motion processing in communication behaviour.

  3. Surfactant-free synthesis of biodegradable, biocompatible, and stimuli-responsive cationic nanogel particles.

    Science.gov (United States)

    Urakami, Hiromitsu; Hentschel, Jens; Seetho, Kellie; Zeng, Hanxiang; Chawla, Kanika; Guan, Zhibin

    2013-10-14

    Nanogels have attracted much attention lately because of their many potential applications, including as nanocarriers for drug and gene delivery. Most nanogels reported previously, however, are not biodegradable, and their synthesis often requires the use of surfactants. Herein we report a surfactant-free method for the preparation of biodegradable, biocompatible, and stimuli-responsive cationic nanogels. The nanogels were synthesized by simply coaservating linear polymer precursors in mixed solvents followed by in situ cross-linking with homobifunctional cross-linkers. The versatility of this approach has been demonstrated by employing two different polymers and various cross-linkers to prepare nanogel particles with diameters ranging from 170 to 220 nm. Specifically, disulfide-containing tetralysine (TetK)- and oligoethylenimine (OEI)-based prepolymers were prepared and the subsequent nanogels were formed by covalently cross-linking the polymer coacervate phase. Nanogel particles are responsive to pH changes, increasing in size and zeta-potential with concomitant lowering of solution pH. Furthermore, as revealed by AFM imaging, nanogel particles were degradable in the presence of glutathione at concentrations similar to those in intracellular environment (10 mM). Both the nanogel and the polymer precursors were determined to exhibit minimal cytotoxicity against fibroblast 3T3 cells by flow cytometric analyses and fluorescent imaging. This study demonstrates a new surfactant-free method for preparing biodegradable, biocompatible, and stimuli-responsive nanogels as potential nanocarriers for the delivery of drugs and genes.

  4. Differential activation of the dorsal striatum by high-calorie visual food stimuli in obese individuals.

    Science.gov (United States)

    Rothemund, Yvonne; Preuschhof, Claudia; Bohner, Georg; Bauknecht, Hans-Christian; Klingebiel, Randolf; Flor, Herta; Klapp, Burghard F

    2007-08-15

    The neural systems regulating food intake in obese individuals remain poorly understood. Previous studies applied positron emission tomography and manipulated hunger and satiety to investigate differences in appetitive processing between obese and normal-weight individuals. However, it is not known whether manipulation of stimulus value may yield different neural activity in obese as compared to control subjects when intrinsic physiological states are kept constant. We used functional magnetic resonance imaging to investigate 13 obese and 13 normal-weight subjects and manipulated food motivation by presenting visual food stimuli differing in their caloric content and energy density. In contrast to controls, obese women selectively activated the dorsal striatum while viewing high-caloric foods. Moreover, in the high-calorie condition body mass index (BMI) predicted activation in the dorsal striatum, anterior insula, claustrum, posterior cingulate, postcentral and lateral orbitofrontal cortex. The results indicate that in obese individuals simple visual stimulation with food stimuli activates regions related to reward anticipation and habit learning (dorsal striatum). Additionally, high-calorie food images yielded BMI-dependent activations in regions associated with taste information processing (anterior insula and lateral orbitofrontal cortex), motivation (orbitofrontal cortex), emotion as well as memory functions (posterior cingulate). Collectively, the results suggest that the observed activation is independent of the physiological states of hunger and satiation, and thus may contribute to pathological overeating and obesity. Some of the observed activations (dorsal striatum, orbitofrontal cortex) are likely to be dopamine-mediated.

  5. Exploring space: Effects of environmental stimuli on self-disclosure

    NARCIS (Netherlands)

    Okken, Vanessa Simone

    2013-01-01

    The research in this dissertation examines the effects of environmental stimuli on self-disclosure during interactions in service environments. Earlier explanations of why behavior can be influenced by environmental factors focused on comfort and affect. In this dissertation experienced spaciousness

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

    Science.gov (United States)

    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. © 2014 Wiley Periodicals, Inc.

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

    Science.gov (United States)

    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…

  8. Processing of Binaural Pitch Stimuli in Hearing-Impaired Listeners

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2009-01-01

    hearingloss; 3: retro-cochlear impairment) were asked to identify the pitch contour of series of five notes of equal duration, ranging from 523 to 784 Hz, played either with Huggins’ binaural pitch stimuli (BP) or perceptually similar, but monaurally detectable, pitches (MP). All subjects from groups 1 and 2...

  9. Infants' Preferential Attention to Sung and Spoken Stimuli

    Science.gov (United States)

    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…

  10. Stress improves selective attention towards emotionally neutral left ear stimuli.

    Science.gov (United States)

    Hoskin, Robert; Hunter, M D; Woodruff, P W R

    2014-09-01

    Research concerning the impact of psychological stress on visual selective attention has produced mixed results. The current paper describes two experiments which utilise a novel auditory oddball paradigm to test the impact of psychological stress on auditory selective attention. Participants had to report the location of emotionally-neutral auditory stimuli, while ignoring task-irrelevant changes in their content. The results of the first experiment, in which speech stimuli were presented, suggested that stress improves the ability to selectively attend to left, but not right ear stimuli. When this experiment was repeated using tonal stimuli the same result was evident, but only for female participants. Females were also found to experience greater levels of distraction in general across the two experiments. These findings support the goal-shielding theory which suggests that stress improves selective attention by reducing the attentional resources available to process task-irrelevant information. The study also demonstrates, for the first time, that this goal-shielding effect extends to auditory perception.

  11. Differences in Sensorimotor Processing of Visual and Proprioceptive Stimuli

    Science.gov (United States)

    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)

  12. Lateralization of Components of Melodic Stimuli: Musicians versus Nonmusicians.

    Science.gov (United States)

    Baumagarte, Roger; Franklin, Elda

    1981-01-01

    Using dichotic listening methodology, 25 musicians and 25 nonmusicians were compared on four cerebral lateralization tasks: melodies, tonal patterns, rhythm patterns, and verbal stimuli. Musicians demonstrated superior performance on the music tasks. Results are interpreted in terms of superior cognitive strategies of musicians as a function of…

  13. Functionalized mesoporous silica nanoparticles for stimuli-responsive and targeted

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, Nikola [Iowa State Univ., Ames, IA (United States)

    2009-12-15

    Construction of functional supramolecular nanoassemblies has attracted great deal of attention in recent years for their wide spectrum of practical applications. Mesoporous silica nanoparticles (MSN) in particular were shown to be effective scaffolds for the construction of drug carriers, sensors and catalysts. Herein, we describe the synthesis and characterization of stimuli-responsive, controlled release MSN-based assemblies for drug delivery.

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

    Science.gov (United States)

    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.

  15. Relative finger position influences whether you can localize tactile stimuli

    NARCIS (Netherlands)

    Overvliet, K.E.; Anema, H.A.; Brenner, E.; Dijkerman, H.C.; Smeets, J.B.J.

    2011-01-01

    To investigate whether the relative positions of the fingers influence tactile localization, participants were asked to localize tactile stimuli applied to their fingertips. We measured the location and rate of errors for three finger configurations: fingers stretched out and together so that they a

  16. Lateralization of Components of Melodic Stimuli: Musicians versus Nonmusicians.

    Science.gov (United States)

    Baumagarte, Roger; Franklin, Elda

    1981-01-01

    Using dichotic listening methodology, 25 musicians and 25 nonmusicians were compared on four cerebral lateralization tasks: melodies, tonal patterns, rhythm patterns, and verbal stimuli. Musicians demonstrated superior performance on the music tasks. Results are interpreted in terms of superior cognitive strategies of musicians as a function of…

  17. Localization of monocular stimuli in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Tam, Wa James; Asakura, Nobuhiko; Ohmi, Masao

    2005-09-01

    We examined the phenomenon in which two physically aligned monocular stimuli appear to be non-collinear when each of them is located in binocular regions that are at different depth planes. Using monocular bars embedded in binocular random-dot areas that are at different depths, we manipulated properties of the binocular areas and examined their effect on the perceived direction and depth of the monocular stimuli. Results showed that (1) the relative visual direction and perceived depth of the monocular bars depended on the binocular disparity and the dot density of the binocular areas, and (2) the visual direction, but not the depth, depended on the width of the binocular regions. These results are consistent with the hypothesis that monocular stimuli are treated by the visual system as binocular stimuli that have acquired the properties of their binocular surrounds. Moreover, partial correlation analysis suggests that the visual system utilizes both the disparity information of the binocular areas and the perceived depth of the monocular bars in determining the relative visual direction of the bars.

  18. Positive erotic picture stimuli for emotion research in heterosexual females.

    Science.gov (United States)

    Jacob, Gitta Anne; Arntz, Arnoud; Domes, Gregor; Reiss, Neele; Siep, Nicolette

    2011-12-30

    In most experimental studies, emotional pictures are widely used as stimulus material. However, there is still a lack of standardization of picture stimuli displaying erotic relationships, despite the association between a number of psychological problems and severe impairments and problems in intimate relationships. The aim of the study was to test a set of erotic stimuli, with the potential to be used in experimental studies, with heterosexual female subjects. Twenty International Affective Picture System (IAPS) pictures and an additional 100 pictures showing romantic but not explicitly sexual scenes and/or attractive single males were selected. All pictures were rated with respect to valence, arousal, and dominance by 41 heterosexual women and compared to pictures with negative, positive, and neutral emotional valence. Erotic IAPS pictures and our additional erotic pictures did not differ in any of the evaluation dimensions. Analyses of variance (ANOVAs) for valence, arousal, and dominance comparing different picture valence categories showed strong effects for category. However, valence was not significantly different between erotic and positive pictures, while arousal and control were not significantly different between positive and neutral pictures. The pictures of our new set are as positive for heterosexual women as highly positive IAPS pictures, but higher in arousal and dominance. The picture set can be used in experimental psychiatric studies requiring high numbers of stimuli per category. Limitations are the restriction of stimuli application to heterosexual females only and to self-report data. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Exploring space: Effects of environmental stimuli on self-disclosure

    NARCIS (Netherlands)

    Okken, V.S.

    2013-01-01

    The research in this dissertation examines the effects of environmental stimuli on self-disclosure during interactions in service environments. Earlier explanations of why behavior can be influenced by environmental factors focused on comfort and affect. In this dissertation experienced spaciousness

  20. Diurnal cortisol amplitude and fronto-limbic activity in response to stressful stimuli.

    Science.gov (United States)

    Cunningham-Bussel, Amy C; Root, James C; Butler, Tracy; Tuescher, Oliver; Pan, Hong; Epstein, Jane; Weisholtz, Daniel S; Pavony, Michelle; Silverman, Michael E; Goldstein, Martin S; Altemus, Margaret; Cloitre, Marylene; Ledoux, Joseph; McEwen, Bruce; Stern, Emily; Silbersweig, David

    2009-06-01

    The development and exacerbation of many psychiatric and neurologic conditions are associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis as measured by aberrant levels of cortisol secretion. Here we report on the relationship between the amplitude of diurnal cortisol secretion, measured across 3 typical days in 18 healthy individuals, and blood oxygen level dependant (BOLD) response in limbic fear/stress circuits, elicited by in-scanner presentation of emotionally negative stimuli, specifically, images of the World Trade Center (WTC) attack. Results indicate that subjects who secrete a greater amplitude of cortisol diurnally demonstrate less brain activation in limbic regions, including the amygdala and hippocampus/parahippocampus, and hypothalamus during exposure to traumatic WTC-related images. Such initial findings can begin to link our understanding, in humans, of the relationship between the diurnal amplitude of a hormone integral to the stress response, and those neuroanatomical regions that are implicated as both modulating and being modulated by that response.

  1. Detection and identification of crowded mirror-image letters in normal peripheral vision.

    Science.gov (United States)

    Chung, Susana T L

    2010-02-01

    Performance for discriminating single mirror-image letters in peripheral vision can be as good as that in central vision, provided that letter size is scaled appropriately [Higgins, K. E., Arditi, A., & Knoblauch, K. (1996). Detection and identification of mirror-image letter pairs in central and peripheral vision. Vision Research, 36, 331-337]. In this study, we asked whether or not there is a reduction in performance for discriminating mirror-image letters when the letters are flanked closely by other letters, compared with unflanked (single) letters; and if so, whether or not this effect is greater in peripheral than in central vision. We compared contrast thresholds for detecting and identifying mirror-image letters "b" and "d" for a range of letter separations, at the fovea and 10 degrees eccentricity, for letters that were scaled in size. For comparison, thresholds were also determined for a pair of non-mirror-image letters "o" and "x". Our principal finding is that there is an additional loss in sensitivity for identifying mirror-image letters ("bd"), compared with non-mirror-image letters ("ox"), when the letters are flanked closely by other letters. The effect is greater in peripheral than central vision. An auxiliary experiment comparing thresholds for letters "d" and "q" vs. "b" and "d" shows that the additional loss in sensitivity for identifying crowded mirror-image letters cannot be attributed to the similarity in letter features between the two letters, but instead, is specific to the axis of symmetry. Our results suggest that in the presence of proximal objects, there is a specific loss in sensitivity for processing broad-band left-right mirror images in peripheral vision.

  2. The impact of mirrors on body image and performance in high and low performing female ballet students.

    Science.gov (United States)

    Radell, Sally A; Adame, Daniel D; Cole, Steven P; Blumenkehl, Nicole J

    2011-09-01

    This study assesses the effect of mirrors on body image and performance in high and low performing female collegiate ballet students. Twenty-three females enrolled in a beginning ballet class were taught using mirrors, and a second group of 23 beginning females were taught without mirrors. All participants completed the Cash 69-item Body Self-Relations Questionnaire during the first and last class of a 14-week semester. They were videotaped performing in the studio during the fifth and fourteenth weeks. Two ballet teachers independently viewed the videotapes to evaluate the dancers' rhythmic accuracy, ease and flow of movement, and mastery of steps and alignment, and rated the students' skill level on a 1-5 scale. For analysis purposes, students whose scores averaged three or higher were categorized as "high performers," and those who averaged less than three were "low performers." Two (mirror, non-mirror) by two (high performance, low performance) by two (pre-test, post-test) repeated measures ANOVAs were used to test class differences over the course of the semester. There were significant 3-way interactions for overweight preoccupation (p < 0.01) and body-areas satisfaction (p < 0.05). Low performers increased in overweight preoccupation in the non-mirror class while decreasing in the mirror class. High performers significantly increased in satisfaction for most areas of their body in the non-mirror class, while there were smaller increases for both low and high performers in the mirror class. It is concluded that while use of the mirror has some benefits in training, higher performing dancers feel better about their body image when they do not use the mirror. Lower performers who use the mirror worry less about their weight; those who do not use the mirror worry more. The mirror may provide feedback that helps low performing dancers feel more comfortable with their weight.

  3. Subliminal presentation of emotionally negative vs positive primes increases the perceived beauty of target stimuli.

    Science.gov (United States)

    Era, Vanessa; Candidi, Matteo; Aglioti, Salvatore Maria

    2015-11-01

    Emotions have a profound influence on aesthetic experiences. Studies using affective priming procedures demonstrate, for example, that inducing a conscious negative emotional state biases the perception of abstract stimuli towards the sublime (Eskine et al. Emotion 12:1071-1074, 2012. doi: 10.1037/a0027200). Moreover, subliminal happy facial expressions have a positive impact on the aesthetic evaluation of abstract art (Flexas et al. PLoS ONE 8:e80154, 2013). Little is known about how emotion influences aesthetic perception of non-abstract, representational stimuli, especially those that are particularly relevant for social behaviour, like human bodies. Here, we explore whether the subliminal presentation of emotionally charged visual primes modulates the explicit subjective aesthetic judgment of body images. Using a forward/backward masking procedure, we presented subliminally positive and negative, arousal-matched, emotional or neutral primes and measured their effect on the explicit evaluation of perceived beauty (high vs low) and emotion (positive vs negative) evoked by abstract and body images. We found that negative primes increased subjective aesthetic evaluations of target bodies or abstract images in comparison with positive primes. No influence of primes on the emotional dimension of the targets was found, thus ruling out an unspecific arousal effect and strengthening the link between emotional valence and aesthetic appreciation. More specifically, that subliminal negative primes increase beauty ratings compared to subliminal positive primes indicates a clear link between negative emotions and positive aesthetic evaluations and vice versa, suggesting a possible link between negative emotion and the experience of sublime in art. The study expands previous research by showing the effect of subliminal negative emotions on the subjective aesthetic evaluation not only of abstract but also of body images.

  4. Threat modulates neural responses to looming visual stimuli.

    Science.gov (United States)

    Vagnoni, Eleonora; Lourenco, Stella F; Longo, Matthew R

    2015-09-01

    Objects on a collision course with an observer produce a specific pattern of optical expansion on the retina known as looming, which in theory exactly specifies the time-to-collision (TTC) of approaching objects. It was recently demonstrated that the affective content of looming stimuli influences perceived TTC, with threatening objects judged as approaching sooner than non-threatening objects. Here, the neural mechanisms by which perceived threat modulates spatiotemporal perception were investigated. Participants judged the TTC of threatening (snakes, spiders) or non-threatening (butterflies, rabbits) stimuli, which expanded in size at a rate indicating one of five TTCs. Visual-evoked potentials (VEPs) and oscillatory neural responses measured with electroencephalography were analysed. The arrival time of threatening stimuli was underestimated compared with non-threatening stimuli, though an interaction suggested that this underestimation was not constant across TTCs. Further, both speed of approach and threat modulated both VEPs and oscillatory responses. Speed of approach modulated the N1 parietal and oscillations in the beta band. Threat modulated several VEP components (P1, N1 frontal, N1 occipital, early posterior negativity and late positive potential) and oscillations in the alpha and high gamma band. The results for the high gamma band suggest an interaction between these two factors. Previous evidence suggests that looming stimuli activate sensorimotor areas, even in the absence of an intended action. The current results show that threat disrupts the synchronization over the sensorimotor areas that are likely activated by the presentation of a looming stimulus. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

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

    Science.gov (United States)

    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.

  6. Sex differences in emotional and psychophysiological responses to musical stimuli.

    Science.gov (United States)

    Nater, Urs M; Abbruzzese, Elvira; Krebs, Monika; Ehlert, Ulrike

    2006-11-01

    Although it is known that men and women differ in their music preferences and emotional reactions to music, little is known about sex differences in physiological reactions to music. In our study, we therefore set out to examine the differential reactivity to two musical stimuli that elicit distinct psychological and physiological reaction patterns. Fifty-three healthy subjects (mean age: 26.13, SD: 3.97; 26 males, 27 females) were examined. Heart rate, electrodermal activity, skin temperature, salivary cortisol, salivary alpha-amylase, and psychological variables were assessed during the course of the whole study. Following baseline assessment, two musical stimuli, which were carefully selected and rated in a pre-study as relaxing and pleasant (renaissance music) and arousing and unpleasant (heavy metal), respectively, were introduced. They were presented on two different days in a randomized order. Whereas psychological variables did not differ between men and women, results of electrophysiological measures indicate significantly different reactivity patterns between men and women. Women displayed elevated response curves to the arousing and unpleasant stimulus, whereas men did not. However, no differences were found with regards to endocrine measures in saliva. Our results demonstrate sex differences in reactivity patterns to musical stimuli in psychophysiological measures. In our study, we were able to show that women tend to show hypersensitivity to aversive musical stimuli. This finding is in accordance with previous literature on sex differences in emotion research. Furthermore, our study indicates that the confounding effects of sex differences have to be considered when using musical stimuli for emotion induction.

  7. Detection of differential viewing patterns to erotic and non-erotic stimuli using eye-tracking methodology.

    Science.gov (United States)

    Lykins, Amy D; Meana, Marta; Kambe, Gretchen

    2006-10-01

    As a first step in the investigation of the role of visual attention in the processing of erotic stimuli, eye-tracking methodology was employed to measure eye movements during erotic scene presentation. Because eye-tracking is a novel methodology in sexuality research, we attempted to determine whether the eye-tracker could detect differences (should they exist) in visual attention to erotic and non-erotic scenes. A total of 20 men and 20 women were presented with a series of erotic and non-erotic images and tracked their eye movements during image presentation. Comparisons between erotic and non-erotic image groups showed significant differences on two of three dependent measures of visual attention (number of fixations and total time) in both men and women. As hypothesized, there was a significant Stimulus x Scene Region interaction, indicating that participants visually attended to the body more in the erotic stimuli than in the non-erotic stimuli, as evidenced by a greater number of fixations and longer total time devoted to that region. These findings provide support for the application of eye-tracking methodology as a measure of visual attentional capture in sexuality research. Future applications of this methodology to expand our knowledge of the role of cognition in sexuality are suggested.

  8. How Does Adult Attachment Affect Human Recognition of Love-related and Sex-related Stimuli: An ERP Study.

    Science.gov (United States)

    Hou, Juan; Chen, Xin; Liu, Jinqun; Yao, Fangshu; Huang, Jiani; Ndasauka, Yamikani; Ma, Ru; Zhang, Yuting; Lan, Jing; Liu, Lu; Fang, Xiaoyi

    2016-01-01

    In the present study, we investigated the relationship among three emotion-motivation systems (adult attachment, romantic love, and sex). We recorded event-related potentials in 37 healthy volunteers who had experienced romantic love while they viewed SEX, LOVE, FRIEND, SPORT, and NEUTRAL images. We also measured adult attachment styles, level of passionate love and sexual attitudes. As expected, results showed that, firstly, response to love-related image-stimuli and sex-related image-stimuli on the electrophysiological data significantly different on N1, N2, and positive slow wave (PSW) components. Secondly, the different adult attachment styles affected individuals' recognition processing in response to love-related and sex-related images, especially, to sex-related images. Further analysis showed that voltages elicited by fearful attachment style individuals were significantly lower than voltages elicited by secure and dismissing attachment style individuals on sex-related images at frontal sites, on N1 and N2 components. Thirdly, from behavior data, we found that adult attachment styles were not significantly related to any dimension of sexual attitudes but were significantly related to passionate love scale (PLS) total points. Thus, the behavior results were not in line with the electrophysiological results. The present study proved that adult attachment styles might mediate individuals' lust and attraction systems.

  9. What's the meaning of this? A behavioral and neurophysiological investigation into the principles behind the classification of visual emotional stimuli.

    Science.gov (United States)

    Czekóová, Kristína; Shaw, Daniel J; Urbánek, Tomáš; Chládek, Jan; Lamoš, Martin; Roman, Robert; Brázdil, Milan

    2016-08-01

    Two experiments were performed to investigate the principles by which emotional stimuli are classified on the dimensions of valence and arousal. In Experiment 1, a large sample of healthy participants rated emotional stimuli according to both broad dimensions. Hierarchical cluster analyses performed on these ratings revealed that stimuli were clustered according to their semantic content at the beginning of the agglomerative process. Example semantic themes include food, violence, nudes, death, and objects. Importantly, this pattern occurred in a parallel fashion for ratings on both dimensions. In Experiment 2, we investigated if the same semantic clusters were differentiated at the neurophysiological level. Intracerebral EEG was recorded from 18 patients with intractable epilepsy who viewed the same set of stimuli. Not only did electrocortical responses differentiate between these data-defined semantic clusters, they converged with the behavioral measurements to highlight the importance of categories associated with survival and reproduction. These findings provide strong evidence that the semantic content of affective material influences their classification along the broad dimensions of valence and arousal, and this principle of categorization exerts an effect on the evoked emotional response. Future studies should consider data-driven techniques rather than normative ratings to identify more specific, semantically related emotional images.

  10. The Bank of Standardized Stimuli (BOSS, a new set of 480 normative photos of objects to be used as visual stimuli in cognitive research.

    Directory of Open Access Journals (Sweden)

    Mathieu B Brodeur

    Full Text Available There are currently stimuli with published norms available to study several psychological aspects of language and visual cognitions. Norms represent valuable information that can be used as experimental variables or systematically controlled to limit their potential influence on another experimental manipulation. The present work proposes 480 photo stimuli that have been normalized for name, category, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. Stimuli are also available in grayscale, blurred, scrambled, and line-drawn version. This set of objects, the Bank Of Standardized Stimuli (BOSS, was created specifically to meet the needs of scientists in cognition, vision and psycholinguistics who work with photo stimuli.

  11. Neonate Auditory Brainstem Responses to CE-Chirp and CE-Chirp Octave Band Stimuli I: Versus Click and Tone Burst Stimuli.

    Science.gov (United States)

    Cobb, Kensi M; Stuart, Andrew

    The purpose of the study was to generate normative auditory brainstem response (ABR) wave component peak latency and amplitude values for neonates with air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli (i.e., 500, 1000, 2000, and 4000 Hz). A second objective was to compare neonate ABRs to CE-Chirp stimuli with ABR responses to traditional click and tone burst stimuli with the same stimulus parameters. Participants were 168 healthy neonates. ABRs were obtained to air- and bone-conducted CE-Chirp and click stimuli and air-conducted CE-Chirp octave band and tone burst stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps and clicks. The effect of stimulus level was also examined with bone-conducted CE-Chirps and clicks and air-conducted CE-Chirp octave band stimuli. In general, ABR wave V amplitudes to air- and bone-conducted CE-Chirp stimuli were significantly larger (p CE-Chirp and CE-Chirp octave band stimuli relative to traditional click and tone burst stimuli. ABRs to air- and bone-conducted CE-Chirps and CE-Chirp octave band stimuli may be valuable in the assessment of newborn infants. However, the prognostic value of such stimuli needs to be validated.

  12. Reduced modulation of thalamocortical connectivity during exposure to sensory stimuli in ASD.

    Science.gov (United States)

    Green, Shulamite A; Hernandez, Leanna; Bookheimer, Susan Y; Dapretto, Mirella

    2017-05-01

    Recent evidence for abnormal thalamic connectivity in autism spectrum disorders (ASD) and sensory processing disorders suggests the thalamus may play a role in sensory over-responsivity (SOR), an extreme negative response to sensory stimuli, which is common in ASD. However, there is yet little understanding of changes in thalamic connectivity during exposure to aversive sensory inputs in individuals with ASD. In particular, the pulvinar nucleus of the thalamus is implicated in atypical sensory processing given its role in selective attention, regulation, and sensory integration. This study aimed to examine the role of pulvinar connectivity in ASD during mildly aversive sensory input. Functional magnetic resonance imaging was used to examine connectivity with the pulvinar during exposure to mildly aversive auditory and tactile stimuli in 38 youth (age 9-17; 19 ASD, 19 IQ-matched typically developing (TD)). Parents rated children's SOR severity on two standard scales. Compared to TD, ASD participants displayed aberrant modulation of connectivity between pulvinar and cortex (including sensory-motor and prefrontal regions) during sensory stimulation. In ASD participants, pulvinar-amygdala connectivity was correlated with severity of SOR symptoms. Deficits in modulation of thalamocortical connectivity in youth with ASD may reflect reduced thalamo-cortical inhibition in response to sensory stimulation, which could lead to difficulty filtering out and/or integrating sensory information. An increase in amygdala connectivity with the pulvinar might be partially responsible for deficits in selective attention as the amygdala signals the brain to attend to distracting sensory stimuli. Autism Res 2017, 10: 801-809. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

  13. Behavioural evidence of a dissociation between voice gender categorization and phoneme categorization using auditory morphed stimuli

    Directory of Open Access Journals (Sweden)

    Cyril R Pernet

    2014-01-01

    Full Text Available Both voice gender and speech perception rely on neuronal populations located in the peri-sylvian areas. However, whilst functional imaging studies suggest a left versus right hemisphere and anterior versus posterior dissociation between voice and speech categorization, psycholinguistic studies on talker variability suggest that these two processes (voice and speech categorization share common mechanisms. In this study, we investigated the categorical perception of voice gender (male vs. female and phonemes (/pa/ vs. /ta/ using the same stimulus continua generated by morphing. This allowed the investigation of behavioural differences while controlling acoustic characteristics, since the same stimuli were used in both tasks. Despite a higher acoustic dissimilarity between items during the phoneme categorization task (a male and female voice producing the same phonemes than the gender task (the same person producing 2 phonemes, results showed that speech information is being processed much faster than voice information. In addition, f0 or timbre equalization did not affect RT, which disagrees with the classical psycholinguistic models in which voice information is stripped away or normalized to access phonetic content. Also, despite similar response (percentages and perceptual (d’ curves, a reverse correlation analysis on acoustic features revealed, as expected, that the formant frequencies of the consonant distinguished stimuli in the phoneme task, but that only the vowel formant frequencies distinguish stimuli in the gender task. The 2nd set of results thus also disagrees with models postulating that the same acoustic information is used for voice and speech. Altogether these results suggest that voice gender categorization and phoneme categorization are dissociated at an early stage on the basis of different enhanced acoustic features that are diagnostic to the task at hand.

  14. Behavioral responses to noxious stimuli shape the perception of pain.

    Science.gov (United States)

    May, Elisabeth S; Tiemann, Laura; Schmidt, Paul; Nickel, Moritz M; Wiedemann, Nina; Dresel, Christian; Sorg, Christian; Ploner, Markus

    2017-03-09

    Pain serves vital protective functions. To fulfill these functions, a noxious stimulus might induce a percept which, in turn, induces a behavioral response. Here, we investigated an alternative view in which behavioral responses do not exclusively depend on but themselves shape perception. We tested this hypothesis in an experiment in which healthy human subjects performed a reaction time task and provided perceptual ratings of noxious and tactile stimuli. A multi-level moderated mediation analysis revealed that behavioral responses are significantly involved in the translation of a stimulus into perception. This involvement was significantly stronger for noxious than for tactile stimuli. These findings show that the influence of behavioral responses on perception is particularly strong for pain which likely reflects the utmost relevance of behavioral responses to protect the body. These observations parallel recent concepts of emotions and entail implications for the understanding and treatment of pain.

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

    Science.gov (United States)

    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.

  16. Gender differences in detecting unanticipated stimuli: an ERP study.

    Science.gov (United States)

    Jin, Yan; Yan, Ke; Zhang, Yuhe; Jiang, Yijie; Tao, Ran; Zheng, Xifu

    2013-03-22

    The aim of the present study was to investigate the gender differences during an emotional anticipation task. Sixteen females and sixteen males participated in the experiment. Event-related potentials (ERPs) were measured in a modified cue-target paradigm and were recorded following stimuli that differed in two dimensions: (1) predictable vs. unpredictable pictures and (2) negative vs. neutral pictures. Cue-induced ERP results demonstrated that females had enhanced positive component (P2) compared to males. Moreover, results showed that during the unpredictable condition, females displayed larger P2 amplitudes in negative and neutral anticipation than males. This study demonstrates that females have greater sensitivity to the unanticipated stimuli, which may contribute to evolution.

  17. Joint attention for stimuli on the hands: Ownership matters

    Directory of Open Access Journals (Sweden)

    Eric eTaylor

    2015-05-01

    Full Text Available 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 & 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.

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

    Science.gov (United States)

    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

  19. Functional stimuli responsive hydrogel devices by self-folding

    Science.gov (United States)

    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.

  20. Stimuli-responsive hydrogels in drug delivery and tissue engineering.

    Science.gov (United States)

    Sood, Nikhil; Bhardwaj, Ankur; Mehta, Shuchi; Mehta, Abhinav

    2016-01-01

    Hydrogels are the three-dimensional network structures obtained from a class of synthetic or natural polymers which can absorb and retain a significant amount of water. Hydrogels are one of the most studied classes of polymer-based controlled drug release. These have attracted considerable attention in biochemical and biomedical fields because of their characteristics, such as swelling in aqueous medium, biocompatibility, pH and temperature sensitivity or sensitivity towards other stimuli, which can be utilized for their controlled zero-order release. The hydrogels are expected to explore new generation of self-regulated delivery system having a wide array of desirable properties. This review highlights the exciting opportunities and challenges in the area of hydrogels. Here, we review different literatures on stimuli-sensitive hydrogels, such as role of temperature, electric potential, pH and ionic strength to control the release of drug from hydrogels.

  1. A Microfluidic Device for Spatiotemporal Delivery of Stimuli to Cells

    Directory of Open Access Journals (Sweden)

    Zubaidah Ningsih

    2015-03-01

    Full Text Available Living cells encounter many stimuli from the immediate environment. Receptors recognize these environmental cues and transduce signals to produce cell responses. The frequency of a signal is now emerging as an important factor determining cell responses. As a componentry system in understanding temporal stimulation, microfluidic devices allow the observation of cell behaviour under dynamic stimulation and controllable environment. In this paper we describe the design, construction and characterization of a microfluidic device suitable for cell stimulation studies.

  2. Stimuli responsive smart-gels realized via modular protein design

    OpenAIRE

    2010-01-01

    Smart-gels have a variety of applications including tissue engineering and controlled drug delivery. Here we present a modular, bottom-up approach that permits the creation of protein-based smart-gels with encoded morphology, functionality, and responsiveness to external stimuli. The properties of these gels are encoded by the proteins from which they are synthesized. In particular, the strength and density of the network of intermolecular cross-links are specified by the interactions of the ...

  3. Attention bias for paranoia-relevant visual stimuli in schizophrenia.

    Science.gov (United States)

    Moritz, Steffen; Laudan, Anna

    2007-09-01

    A number of studies indicate that patients with schizophrenia share a bias for paranoia-relevant material. The presence of an attentional bias for such stimuli would be of utter importance for our pathogenetic understanding of the disorder in view of ample evidence that patients with schizophrenia gather little information before arriving at strong conclusions: A both scarce and affectively biased data selection of available information may heavily distort its inner representation and thus prompt the formation of false beliefs. To date, the profile of this putative attentional bias in schizophrenia (e.g., automatic vs. controlled; hypervigilance towards vs. problems to disengage from such stimuli) is not fully uncovered. To shed light on this aspect of information processing in schizophrenia, we administered a novel task based on the inhibition of return paradigm (IOR). Twenty-four schizophrenia patients and thirty-four healthy controls were presented neutral (e.g., cup), anxiety-relevant (e.g., shark), and paranoia-relevant cue pictures (e.g., gun) at either of two possible locations. Subsequent to either a short or long interval, a target appeared at the same or opposite location. Participants were requested to press a spatially corresponding button. Both currently paranoid and nonparanoid schizophrenia patients responded faster to all kinds of targets following paranoia-relevant pictures, that is, such stimuli speeded reaction times irrespective of the cue-target interval and spatial correspondence. This indicates that paranoia-relevant information generally alerts patients more than other stimuli and facilitates processing of subsequent information. Possible implications of this finding for our understanding of delusion formation and maintenance are outlined.

  4. Mechanism of unpinning spirals by a series of stimuli.

    Science.gov (United States)

    Gao, Xiang; Zhang, Hong

    2014-06-01

    Antitachycardia pacing (ATP) is widely used to terminate tachycardia before it proceeds to lethal fibrillation. The important prerequisite for successful ATP is unpinning of the spirals anchored to the obstacle by a series of stimuli. Here, to understand the mechanism of unpinning spirals by ATP, we propose a theoretical explanation based on a nonlinear eikonal relation and a kinematical model. The theoretical results are quantitatively consistent with the numerical simulations in both weak and high excitabilities.

  5. Music Influences Ratings of the Affect of Visual Stimuli

    OpenAIRE

    Waldie E Hanser; Mark, Ruth E

    2013-01-01

    This review provides an overview of recent studies that have examined how music influences the judgment of emotional stimuli, including affective pictures and film clips. The relevant findings are incorporated within a broader theory of music and emotion, and suggestions for future research are offered.Music is important in our daily lives, and one of its primary uses by listeners is the active regulation of one's mood. Despite this widespread use as a regulator of mood and its general pervas...

  6. Neural correlates of quality during perception of audiovisual stimuli

    CERN Document Server

    Arndt, Sebastian

    2016-01-01

    This book presents a new approach to examining perceived quality of audiovisual sequences. It uses electroencephalography to understand how exactly user quality judgments are formed within a test participant, and what might be the physiologically-based implications when being exposed to lower quality media. The book redefines experimental paradigms of using EEG in the area of quality assessment so that they better suit the requirements of standard subjective quality testings. Therefore, experimental protocols and stimuli are adjusted accordingly. .

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

    Science.gov (United States)

    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

  8. Spatial localization of electrotactile stimuli on the fingertip in humans.

    Science.gov (United States)

    Bobich, L R; Warren, J P; Sweeney, J D; Tillery, S I Helms; Santello, M

    2007-12-01

    This study was designed to determine the extent to which sensations elicited by discrete electrotactile stimulation can be spatially localized, with a qualitative comparison to mechanical stimulation, in a 2 x 2 electrode array on the fingertip. Electrotactile stimulation was delivered in two modes: (1) same current to all locations (constant) or (2) current adjusted to perceptual threshold of each location (varied). For each stimulus location, subjects were asked to identify the location of the stimulus. Mechanical stimulation of the same locations on the fingerpad was delivered through von Frey hairs (0.07, 0.2 and 0.4 g). The percentage of accurate responses was computed for all stimulation modes. We found that the accuracy of discrimination of stimulus location in both the constant (46%) and varied (40%) electrotactile stimulation modes was significantly higher than chance level (25%; p < 0.01). Furthermore, subjects were significantly more accurate in discriminating electrotactile stimuli in the constant than in the varied mode (p < 0.05). We also found that the accuracy of spatial discrimination was dependent on stimulation site for mechanical, but not electrotactile stimulation. Finally, we found a significant difference in accuracy over the duration of the experiment only for mechanical modes, which may indicate that electrotactile stimuli are less biased over time. These results suggest that, although low in accuracy, human subjects are able to extract spatial information from electrotactile stimuli. Further research is needed to optimize the amount of the information that can be delivered through electrotactile stimulation.

  9. Dynamism of Stimuli-Responsive Nanohybrids: Environmental Implications

    Directory of Open Access Journals (Sweden)

    Jaime Plazas-Tuttle

    2015-06-01

    Full Text Available Nanomaterial science and design have shifted from generating single passive nanoparticles to more complex and adaptive multi-component nanohybrids. These adaptive nanohybrids (ANHs are designed to simultaneously perform multiple functions, while actively responding to the surrounding environment. ANHs are engineered for use as drug delivery carriers, in tissue-engineered templates and scaffolds, adaptive clothing, smart surface coatings, electrical switches and in platforms for diversified functional applications. Such ANHs are composed of carbonaceous, metallic or polymeric materials with stimuli-responsive soft-layer coatings that enable them to perform such switchable functions. Since ANHs are engineered to dynamically transform under different exposure environments, evaluating their environmental behavior will likely require new approaches. Literature on polymer science has established a knowledge core on stimuli-responsive materials. However, translation of such knowledge to environmental health and safety (EHS of these ANHs has not yet been realized. It is critical to investigate and categorize the potential hazards of ANHs, because exposure in an unintended or shifting environment could present uncertainty in EHS. This article presents a perspective on EHS evaluation of ANHs, proposes a principle to facilitate their identification for environmental evaluation, outlines a stimuli-based classification for ANHs and discusses emerging properties and dynamic aspects for systematic EHS evaluation.

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

    Science.gov (United States)

    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 0.05). Therefore, there is a biostimulatory effect of mating at the time beef cattle females are detected in estrus, on pregnancy rates to AI.

  11. Differences in Swallowing between High and Low Concentration Taste Stimuli

    Directory of Open Access Journals (Sweden)

    Ahmed Nagy

    2014-01-01

    Full Text Available Taste is a property that is thought to potentially modulate swallowing behavior. Whether such effects depend on taste, intensity remains unclear. This study explored differences in the amplitudes of tongue-palate pressures in swallowing as a function of taste stimulus concentration. Tongue-palate pressures were collected in 80 healthy women, in two age groups (under 40, over 60, stratified by genetic taste status (nontasters, supertasters. Liquids with different taste qualities (sweet, sour, salty, and bitter were presented in high and low concentrations. General labeled magnitude scale ratings captured perceived taste intensity and liking/disliking of the test liquids. Path analysis explored whether factors of taste, concentration, age group, and/or genetic taste status impacted: (1 perceived intensity; (2 palatability; and (3 swallowing pressures. Higher ratings of perceived intensity were found in supertasters and with higher concentrations, which were more liked/disliked than lower concentrations. Sweet stimuli were more palatable than sour, salty, or bitter stimuli. Higher concentrations elicited stronger tongue-palate pressures independently and in association with intensity ratings. The perceived intensity of a taste stimulus varies as a function of stimulus concentration, taste quality, participant age, and genetic taste status and influences swallowing pressure amplitudes. High-concentration salty and sour stimuli elicit the greatest tongue-palate pressures.

  12. The Visual Mismatch Negativity Elicited with Visual Speech Stimuli

    Directory of Open Access Journals (Sweden)

    Benjamin T. Files

    2013-07-01

    Full Text Available The visual mismatch negativity (vMMN, deriving from the brain’s response to stimulus deviance, is thought to be generated by the cortex that represents the stimulus. The vMMN response to visual speech stimuli was used in a study of the lateralization of visual speech processing. Previous research suggested that the right posterior temporal cortex has specialization for processing simple non-speech face gestures, and the left posterior temporal cortex has specialization for processing visual speech gestures. Here, visual speech consonant-vowel (CV stimuli with controlled perceptual dissimilarities were presented in an electroencephalography (EEG vMMN paradigm. The vMMNs were obtained using the comparison of event-related potentials (ERPs for separate CVs in their roles as deviant versus their roles as standard. Four separate vMMN contrasts were tested, two with the perceptually far deviants (i.e., zha or fa and two with the near deviants (i.e., zha or ta. Only far deviants evoked the vMMN response over the left posterior temporal cortex. All four deviants evoked vMMNs over the right posterior temporal cortex. The results are interpreted as evidence that the left posterior temporal cortex represents speech stimuli that are perceived as different consonants, and the right posterior temporal cortex represents face gestures that may not be discriminable as different CVs.

  13. Cilioplasm is a cellular compartment for calcium signaling in response to mechanical and chemical stimuli.

    Science.gov (United States)

    Jin, Xingjian; Mohieldin, Ashraf M; Muntean, Brian S; Green, Jill A; Shah, Jagesh V; Mykytyn, Kirk; Nauli, Surya M

    2014-06-01

    Primary cilia with a diameter of ~200 nm have been implicated in development and disease. Calcium signaling within a primary cilium has never been directly visualized and has therefore remained a speculation. Fluid-shear stress and dopamine receptor type-5 (DR5) agonist are among the few stimuli that require cilia for intracellular calcium signal transduction. However, it is not known if these stimuli initiate calcium signaling within the cilium or if the calcium signal originates in the cytoplasm. Using an integrated single-cell imaging technique, we demonstrate for the first time that calcium signaling triggered by fluid-shear stress initiates in the primary cilium and can be distinguished from the subsequent cytosolic calcium response through the ryanodine receptor. Importantly, this flow-induced calcium signaling depends on the ciliary polycystin-2 calcium channel. While DR5-specific agonist induces calcium signaling mainly in the cilioplasm via ciliary CaV1.2, thrombin specifically induces cytosolic calcium signaling through the IP3 receptor. Furthermore, a non-specific calcium ionophore triggers both ciliary and cytosolic calcium responses. We suggest that cilia not only act as sensory organelles but also function as calcium signaling compartments. Cilium-dependent signaling can spread to the cytoplasm or be contained within the cilioplasm. Our study thus provides the first model to understand signaling within the cilioplasm of a living cell.

  14. Thermal facial reactivity patterns predict social categorization bias triggered by unconscious and conscious emotional stimuli.

    Science.gov (United States)

    Ponsi, Giorgia; Panasiti, Maria Serena; Rizza, Giulia; Aglioti, Salvatore Maria

    2017-08-30

    Members of highly social species decode, interpret, and react to the emotion of a conspecific depending on whether the other belongs to the same (ingroup) or different (outgroup) social group. While studies indicate that consciously perceived emotional stimuli drive social categorization, information about how implicit emotional stimuli and specific physiological signatures affect social categorization is lacking. We addressed this issue by exploring whether subliminal and supraliminal affective priming can influence the categorization of neutral faces as ingroup versus outgroup. Functional infrared thermal imaging was used to investigate whether the effect of affective priming on the categorization decision was moderated by the activation of the sympathetic nervous system (SNS). During the subliminal condition, we found that stronger SNS activation after positive or negative affective primes induced ingroup and outgroup face categorization, respectively. The exact opposite pattern (i.e. outgroup after positive and ingroup after negative primes) was observed in the supraliminal condition. We also found that misattribution effects were stronger in people with low emotional awareness, suggesting that this trait moderates how one recognizes SNS signals and employs them for unrelated decisions. Our results allow the remarkable implication that low-level affective reactions coupled with sympathetic activation may bias social categorization. © 2017 The Author(s).

  15. The relationship between age and brain response to visual erotic stimuli in healthy heterosexual males.

    Science.gov (United States)

    Seo, Y; Jeong, B; Kim, J-W; Choi, J

    2010-01-01

    The various changes of sexuality, including decreased sexual desire and erectile dysfunction, are also accompanied with aging. To understand the effect of aging on sexuality, we explored the relationship between age and the visual erotic stimulation-related brain response in sexually active male subjects. Twelve healthy, heterosexual male subjects (age 22-47 years) were recorded the functional magnetic resonance imaging (fMRI) signals of their brain activation elicited by passive viewing erotic (ERO), happy-faced (HA) couple, food and nature pictures. Mixed effect analysis and correlation analysis were performed to investigate the relationship between the age and the change of brain activity elicited by erotic stimuli. Our results showed age was positively correlated with the activation of right occipital fusiform gyrus and amygdala, and negatively correlated with the activation of right insula and inferior frontal gyrus. These findings suggest age might be related with functional decline in brain regions being involved in both interoceptive sensation and prefrontal modulation while it is related with the incremental activity of the brain region for early processing of visual emotional stimuli in sexually healthy men.

  16. Induction of social behavior in zebrafish: live versus computer animated fish as stimuli.

    Science.gov (United States)

    Qin, Meiying; Wong, Albert; Seguin, Diane; Gerlai, Robert

    2014-06-01

    The zebrafish offers an excellent compromise between system complexity and practical simplicity and has been suggested as a translational research tool for the analysis of human brain disorders associated with abnormalities of social behavior. Unlike laboratory rodents zebrafish are diurnal, thus visual cues may be easily utilized in the analysis of their behavior and brain function. Visual cues, including the sight of conspecifics, have been employed to induce social behavior in zebrafish. However, the method of presentation of these cues and the question of whether computer animated images versus live stimulus fish have differential effects have not been systematically analyzed. Here, we compare the effects of five stimulus presentation types: live conspecifics in the experimental tank or outside the tank, playback of video-recorded live conspecifics, computer animated images of conspecifics presented by two software applications, the previously employed General Fish Animator, and a new application Zebrafish Presenter. We report that all stimuli were equally effective and induced a robust social response (shoaling) manifesting as reduced distance between stimulus and experimental fish. We conclude that presentation of live stimulus fish, or 3D images, is not required and 2D computer animated images are sufficient to induce robust and consistent social behavioral responses in zebrafish.

  17. Identifying attentional bias and emotional response after appearance-related stimuli exposure.

    Science.gov (United States)

    Cho, Ara; Kwak, Soo-Min; Lee, Jang-Han

    2013-01-01

    The effect of media images has been regarded as a significant variable in the construction or in the activation of body images. Individuals who have a negative body image use avoidance coping strategies to minimize damage to their body image. We identified attentional biases and negative emotional responses following exposure to body stimuli. Female university students were divided into two groups based on their use of avoidance coping strategies (high-level group: high avoidance [HA]; low-group: low avoidance [LA]), and were assigned to two different conditions (exposure to thin body pictures, ET, and exposure to oversized body pictures, EO). Results showed that the HA group paid more attention to slim bodies and reported more negative emotions than the LA group, and that the EO had more negative effects than the ET. We suggest that HAs may attend more to slim bodies as a way of avoiding overweight bodies, influenced by social pressure, and in the search for a compensation of a positive emotional balance. However, attentional bias toward slim bodies can cause an upward comparison process, leading to increased body dissatisfaction, which is the main factor in the development of eating disorders (EDs). Therefore, altering avoidance coping strategies should be considered for people at risk of EDs.

  18. Aversive and non-reward learning in the fire-bellied toad using familiar and unfamiliar prey stimuli

    Institute of Scientific and Technical Information of China (English)

    Ursula DICKE; Antje HEIDORN; Gerhard ROTH

    2011-01-01

    The present study investigated how snapping behavior toward familiar and unfamiliar prey is modified by reward omission and aversive conditioning in the fure-bellied toad Bombina orientalis.Toads were trained to snap at cricket images by rewarding them with live crickets.The task was learned,and the learning criterion (10 snapping responses within 2 minutes) was reached in all individuals investigated.Subsequent reward omission did not alter the frequency of snapping to the familiar cricket stimulus.Snapping decreased only in some individuals,when a mild foot shock was applied at snapping.However,at presentation of images of hitherto unfamiliar meal worms and foot-shock application at snapping to the stimulus,the majority of toads diminished snapping significantly.Snapping responses decreased more rapidly,when snapping at meal worms was not rewarded or a footshock was applied uncorrelated to the presentation of or snapping at meal worms.These results demonstrate that in toads familiarity and unfamiliarity of prey stimuli are important factors in aversive learning,because well-trained responses to familiar stimuli become immune against reward omission.Furthermore,at presentation of unfamiliar stimuli,omission of reward and uncorrelated footshock had a stronger aversive effect than correlated footshock [Current Zoology 57 (6):709-716,2011 ].

  19. Perceived sexual orientation based on vocal and facial stimuli is linked to self-rated sexual orientation in Czech men.

    Directory of Open Access Journals (Sweden)

    Jaroslava Varella Valentova

    Full Text Available 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.

  20. Perceived sexual orientation based on vocal and facial stimuli is linked to self-rated sexual orientation in Czech men.

    Science.gov (United States)

    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.

  1. The effects of warning cues and attention-capturing stimuli on the sustained attention to response task.

    Science.gov (United States)

    Finkbeiner, Kristin M; Wilson, Kyle M; Russell, Paul N; Helton, William S

    2015-04-01

    Performance on the sustained attention to response task (SART) is often characterized by a speed-accuracy trade-off, and SART performance may be influenced by strategic factors (Head and Helton Conscious Cogn 22: 913-919, 2013). Previous research indicates a significant difference between reliable and unreliable warning cues on response times and errors (commission and omission), suggesting that SART tasks are influenced by strategic factors (Helton et al. Conscious Cogn 20: 1732-1737, 2011; Exp Brain Res 209: 401-407, 2011). With regards to warning stimuli, we chose to use cute images (exhibiting infantile features) during a SART, as previous literature indicates cute images cause participants to engage attention. If viewing cute things makes the viewer exert more attention than normal, then exposure to cute stimuli during the SART should improve performance if SART performance is a measure of perceptual coupling. Reliable warning cues were shown to reduce both response time and errors of commission, and increase errors of omission, relative to unreliable warning cues. Cuteness of the warning stimuli, however, had no significant effect on SART performance. These results suggest the importance of strategic factors in SART performance, not increased attention, and add to the growing literature which suggests the SART is not a good measure of sustained attention, vigilance or perceptual coupling.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  4. Temporal response properties to second-order visual stimuli in the LGN of cats

    Institute of Scientific and Technical Information of China (English)

    XU PengJing; YE Xiang; ZHOU Yifeng

    2007-01-01

    Visual stimuli occurring naturally are rich in instances of objects delineated from the backgrounds only by differences in luminance, which is called first-order stimuli, as well as those defined by differences of contrast or texture, referred to as second-order stimuli.The neuronal mechanism for processing second-order stimuli is still unclear.In this study, we compared the responses of cat LGN (lateral geniculate nucleus) cells to second-order stimuli at five temporal frequencies to their responses to first-order stimuli.Our results showed that most LGN cells can be evoked by second-order stimuli, and their firing rates to second-order stimuli decreased relative to first-order stimuli as temporal frequency increased from 0.5 to 8 Hz; moreover the ratio of a nonlinear to linear factor had a higher value in the responses to second-order stimuli than to first-order stimuli.We also found that the responses of Y-cells to second-order stimuli were significantly higher than the responses of X-cells, suggesting the Y-cells have a more important role in the processing of second-order stimuli.All these results reveal that first-order and second-order signals might be processed in separate 'streams' of the visual system.

  5. A low-cost and versatile system for projecting wide-field visual stimuli within fMRI scanners.

    Science.gov (United States)

    Greco, V; Frijia, F; Mikellidou, K; Montanaro, D; Farini, A; D'Uva, M; Poggi, P; Pucci, M; Sordini, A; Morrone, M C; Burr, D C

    2016-06-01

    We have constructed and tested a custom-made magnetic-imaging-compatible visual projection system designed to project on a very wide visual field (~80°). A standard projector was modified with a coupling lens, projecting images into the termination of an image fiber. The other termination of the fiber was placed in the 3-T scanner room with a projection lens, which projected the images relayed by the fiber onto a screen over the head coil, viewed by a participant wearing magnifying goggles. To validate the system, wide-field stimuli were presented in order to identify retinotopic visual areas. The results showed that this low-cost and versatile optical system may be a valuable tool to map visual areas in the brain that process peripheral receptive fields.

  6. United we sense, divided we fail: context-driven perception of ambiguous visual stimuli

    NARCIS (Netherlands)

    Klink, P. C; van Wezel, Richard Jack Anton; van Ee, R.

    2012-01-01

    Ambiguous visual stimuli provide the brain with sensory information that contains conflicting evidence for multiple mutually exclusive interpretations. Two distinct aspects of the phenomenological experience associated with viewing ambiguous visual stimuli are the apparent stability of perception

  7. Transcranial direct current stimulation of the prefrontal cortex increases attention to visual target stimuli.

    Science.gov (United States)

    Vierheilig, Nina; Mühlberger, Andreas; Polak, Thomas; Herrmann, Martin J

    2016-10-01

    Both functional imaging or EEG studies and studies including neurological patients found the dorsolateral prefrontal cortex (dLPFC) to be an important brain area for the processing of emotion and attention. The aim of the present study was to investigate whether emotion and attention can be modulated through bilateral transcranial direct current stimulation (tDCS) of the dLPFC. Therefore, we measured electroencephalographic occipital (early posterior negativity, EPN) and parietal ERPs (late positive potential, LPP) during an emotional picture viewing paradigm with an additional attentional instruction while applying bilateral anodal and cathodal tDC-stimulation to the left and right dLPFC. Beyond the well-known emotion and attention effects for both EPN and LPP, we found that left cathodal/right anodal tDCS leads to increased LPP amplitudes to target stimuli. In contrast to our hypothesis bilateral tDCS over the dLPFC did not influence emotional processing.

  8. Optical droplet vaporization of nanoparticle-loaded stimuli-responsive microbubbles

    Science.gov (United States)

    Si, Ting; Li, Guangbin; Wu, Qiang; Zhu, Zhiqiang; Luo, Xisheng; Xu, Ronald X.

    2016-03-01

    A capillary co-flow focusing process is developed to generate stimuli-responsive microbubbles (SRMs) that comprise perfluorocarbon (PFC) suspension of silver nanoparticles (SNPs) in a lipid shell. Upon continuous laser irradiation at around their surface plasmon resonance band, the SNPs effectively absorb electromagnetic energy, induce heat accumulation in SRMs, trigger PFC vaporization, and eventually lead to thermal expansion and fragmentation of the SRMs. This optical droplet vaporization (ODV) process is further simulated by a theoretical model that combines heat generation of SNPs, phase change of PFC, and thermal expansion of SRMs. The model is validated by benchtop experiments, where the ODV process is monitored by microscopic imaging. The effects of primary process parameters on behaviors of ODV are predicted by the theoretical model, indicating the technical feasibility for process control and optimization in future drug delivery applications.

  9. Pictures of you: Dot stimuli cause motor contagion in presence of a still human form.

    Science.gov (United States)

    Sparks, S; Sidari, M; Lyons, M; Kritikos, A

    2016-10-01

    In this study, we investigate which visual cues induce participants to encode a non-human motion stimulus in their motor system. Participants performed reach-to-grasp actions to a target after observing a dot moving in a direct or higher-arcing path across a screen. Dot motion occurred in the presence of a meaningless (scrambled human model) stimulus, a still human model, or a human model performing a direct or exaggeratedly curved reach to a target. Our results show that observing the dot displacement causes motor contagion (changes in the height of the observer's hand trajectory) when a human form was visually present in the background (either moving or still). No contagion was evident, however, when this human context was absent (i.e., human image scrambled and not identifiable). This indicates that visual cues suggestive of human agency can determine whether or not moving stimuli are encoded in the motor system.

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

    DEFF Research Database (Denmark)

    Ponseti, Jorge; Granert, Oliver; Jansen, Olav

    2009-01-01

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

  11. How does not responding to appetitive stimuli cause devaluation: Evaluative conditioning or response inhibition?

    Science.gov (United States)

    Chen, Zhang; Veling, Harm; Dijksterhuis, Ap; Holland, Rob W

    2016-12-01

    In a series of 6 experiments (5 preregistered), we examined how not responding to appetitive stimuli causes devaluation. To examine this question, a go/no-go task was employed in which appetitive stimuli were consistently associated with cues to respond (go stimuli), or with cues to not respond (either no-go cues or the absence of cues; no-go stimuli). Change in evaluations of no-go stimuli was compared to change in evaluations of both go stimuli and of stimuli not presented in the task (untrained stimuli). Experiments 1 to 3 show that not responding to appetitive stimuli in a go/no-go task causes devaluation of these stimuli regardless of the presence of an explicit no-go cue. Experiments 4a and 4b show that the devaluation effect of appetitive stimuli is contingent on the percentage of no-go trials; devaluation appears when no-go trials are rare, but disappears when no-go trials are frequent. Experiment 5 shows that simply observing the go/no-go task does not lead to devaluation. Experiment 6 shows that not responding to neutral stimuli does not cause devaluation. Together, these results suggest that devaluation of appetitive stimuli by not responding to them is the result of response inhibition. By employing both go stimuli and untrained stimuli as baselines, alternative explanations are ruled out, and apparent inconsistencies in the literature are resolved. These experiments provide new theoretical insight into the relation between not responding and evaluation, and can be applied to design motor response training procedures aimed at changing people's behavior toward appetitive stimuli. (PsycINFO Database Record

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Jessica L Montoya

    Full Text Available 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

  14. Impact of emotion on consciousness: positive stimuli enhance conscious reportability.

    Directory of Open Access Journals (Sweden)

    Kristine Rømer Thomsen

    Full Text Available Emotion and reward have been proposed to be closely linked to conscious experience, but empirical data are lacking. The anterior cingulate cortex (ACC plays a central role in the hedonic dimension of conscious experience; thus potentially a key region in interactions between emotion and consciousness. Here we tested the impact of emotion on conscious experience, and directly investigated the role of the ACC. We used a masked paradigm that measures conscious reportability in terms of subjective confidence and objective accuracy in identifying the briefly presented stimulus in a forced-choice test. By manipulating the emotional valence (positive, neutral, negative and the presentation time (16 ms, 32 ms, 80 ms we measured the impact of these variables on conscious and subliminal (i.e. below threshold processing. First, we tested normal participants using face and word stimuli. Results showed that participants were more confident and accurate when consciously seeing happy versus sad/neutral faces and words. When stimuli were presented subliminally, we found no effect of emotion. To investigate the neural basis of this impact of emotion, we recorded local field potentials (LFPs directly in the ACC in a chronic pain patient. Behavioural findings were replicated: the patient was more confident and accurate when (consciously seeing happy versus sad faces, while no effect was seen in subliminal trials. Mirroring behavioural findings, we found significant differences in the LFPs after around 500 ms (lasting 30 ms in conscious trials between happy and sad faces, while no effect was found in subliminal trials. We thus demonstrate a striking impact of emotion on conscious experience, with positive emotional stimuli enhancing conscious reportability. In line with previous studies, the data indicate a key role of the ACC, but goes beyond earlier work by providing the first direct evidence of interaction between emotion and conscious experience in the human

  15. [The Contribution of the Orbitofrontal Cortex to the Preference for Visual Stimuli].

    Science.gov (United States)

    Funahashi, Shintaro

    2015-06-01

    Both humans and animals like to watch neutral and biologically insignificant visual stimuli. Behavioral studies have revealed that animals more frequently select stimuli with symmetrical and regular patterns and short movies compared to stimuli with unsymmetrical and irregular patterns and photographs. Preferred visual stimuli can serve as rewards for animals performing behavioral tasks. Preferences for visual stimuli are determined by the magnitude of the pleasant feelings that are experienced when the stimuli are seen. The orbitofrontal cortex is known to participate in the detection and prediction of reward, the estimation of the value of the stimuli as a reward, and positive emotion. Human neuroimaging studies and animal neurophysiological studies have shown that the magnitude of orbitofrontal responses to the presentation of neutral visual stimuli correlates with the strength of the preference for the stimuli in the behavioral studies. These results suggest that the magnitude of orbitofrontal responses to the visual stimuli correlates with the strength of the pleasant feelings that are produced by the stimuli and that the orbitofrontal cortex plays an important role in the judgment of the preference for visual stimuli.

  16. How does not responding to appetitive stimuli cause devaluation: Evaluative conditioning or response inhibition?

    NARCIS (Netherlands)

    Chen, Z.; Veling, H.P.; Dijksterhuis, A.J.; Holland, R.W.

    2016-01-01

    In a series of 6 experiments (5 preregistered), we examined how not responding to appetitive stimuli causes devaluation. To examine this question, a go/no-go task was employed in which appetitive stimuli were consistently associated with cues to respond (go stimuli), or with cues to not respond

  17. How does not responding to appetitive stimuli cause devaluation: Evaluative conditioning or response inhibition?

    NARCIS (Netherlands)

    Chen, Z.; Veling, H.P.; Dijksterhuis, A.J.; Holland, R.W.

    2016-01-01

    In a series of 6 experiments (5 preregistered), we examined how not responding to appetitive stimuli causes devaluation. To examine this question, a go/no-go task was employed in which appetitive stimuli were consistently associated with cues to respond (go stimuli), or with cues to not respond (eit

  18. Ribozymes that can be regulated by external stimuli.

    Science.gov (United States)

    Frommer, Jennifer; Appel, Bettina; Müller, Sabine

    2015-02-01

    Ribozymes have been known for about 30 years, and nowadays are understood well enough to be turned into useful tools for a number of applications in vitro and in vivo. Allosteric ribozymes switch on and off their activity in response to a specific chemical (ligand) or physical (temperature, light) signal. The possibility of controlling ribozyme activity by external stimuli is of particular relevance for applications in different fields, such as environmental and medicinal diagnostics, molecular computing, control of gene expression and others. Herein, we review recent advances and describe selected examples of addressable ribozymes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Hydrophilic-oleophobic stimuli-responsive materials and surfaces

    Science.gov (United States)

    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

  20. Construction of Hindi Speech Stimuli for Eliciting Auditory Brainstem Responses.

    Science.gov (United States)

    Ansari, Mohammad Shamim; Rangasayee, R

    2016-12-01

    Speech-evoked auditory brainstem responses (spABRs) provide considerable information of clinical relevance to describe auditory processing of complex stimuli at the sub cortical level. The substantial research data have suggested faithful representation of temporal and spectral characteristics of speech sounds. However, the spABR are known to be affected by acoustic properties of speech, language experiences and training. Hence, there exists indecisive literature with regards to brainstem speech processing. This warrants establishment of language specific speech stimulus to describe the brainstem processing in specific oral language user. The objective of current study is to develop Hindi speech stimuli for recording auditory brainstem responses. The Hindi stop speech of 40 ms containing five formants was constructed. Brainstem evoked responses to speech sound |da| were gained from 25 normal hearing (NH) adults having mean age of 20.9 years (SD = 2.7) in the age range of 18-25 years and ten subjects (HI) with mild SNHL of mean 21.3 years (SD = 3.2) in the age range of 18-25 years. The statistically significant differences in the mean identification scores of synthesized for speech stimuli |da| and |ga| between NH and HI were obtained. The mean, median, standard deviation, minimum, maximum and 95 % confidence interval for the discrete peaks and V-A complex values of electrophysiological responses to speech stimulus were measured and compared between NH and HI population. This paper delineates a comprehensive methodological approach for development of Hindi speech stimuli and recording of ABR to speech. The acoustic characteristic of stimulus |da| was faithfully represented at brainstem level in normal hearing adults. There was statistically significance difference between NH and HI individuals. This suggests that spABR offers an opportunity to segregate normal speech encoding from abnormal speech processing at sub cortical level, which implies that

  1. Category superiority effects and the processing of auditory images.

    Science.gov (United States)

    Sharps, M J; Pollitt, B K

    1998-04-01

    Music and information appear to be processed by means of the phonological loop, as opposed to the visuospatial sketchpad, in working memory. Is this also true of memory for nonverbal, nonmusical auditory images, such as the characteristic sounds made by objects? In the present study, university students were presented with equivalent verbal stimuli, nonsemantic auditory stimuli, or pictorial stimuli, by category or in random order. Significant category superiority effects (CSEs) were obtained for both verbal and auditory stimuli, but not for pictorial stimuli, consistent with the expectation of phonological loop processing. However, absolute levels of recall for auditory stimuli were significantly higher than for verbal stimuli and did not differ from the levels observed for pictures, suggesting a somewhat intermediate character of processing for nonverbal, nonmusical auditory information.

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

    Directory of Open Access Journals (Sweden)

    Bastian Stippekohl

    Full Text Available 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

  3. Imaging systems and applications: introduction to the feature.

    Science.gov (United States)

    Imai, Francisco H; Linne von Berg, Dale C; Skauli, Torbjørn; Tominaga, Shoji; Zalevsky, Zeev

    2014-05-01

    Imaging systems have numerous applications in industrial, military, consumer, and medical settings. Assembling a complete imaging system requires the integration of optics, sensing, image processing, and display rendering. This issue features original research ranging from design of stimuli for human perception, optics applications, and image enhancement to novel imaging modalities in both color and infrared spectral imaging, gigapixel imaging as well as a systems perspective to imaging.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mikkel Wallentin

    2016-01-01

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

  6. Large crowding zones in peripheral vision for briefly presented stimuli.

    Science.gov (United States)

    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.

  7. Representation of dynamical stimuli in populations of threshold neurons.

    Directory of Open Access Journals (Sweden)

    Tatjana Tchumatchenko

    2011-10-01

    Full Text Available Many sensory or cognitive events are associated with dynamic current modulations in cortical neurons. This raises an urgent demand for tractable model approaches addressing the merits and limits of potential encoding strategies. Yet, current theoretical approaches addressing the response to mean- and variance-encoded stimuli rarely provide complete response functions for both modes of encoding in the presence of correlated noise. Here, we investigate the neuronal population response to dynamical modifications of the mean or variance of the synaptic bombardment using an alternative threshold model framework. In the variance and mean channel, we provide explicit expressions for the linear and non-linear frequency response functions in the presence of correlated noise and use them to derive population rate response to step-like stimuli. For mean-encoded signals, we find that the complete response function depends only on the temporal width of the input correlation function, but not on other functional specifics. Furthermore, we show that both mean- and variance-encoded signals can relay high-frequency inputs, and in both schemes step-like changes can be detected instantaneously. Finally, we obtain the pairwise spike correlation function and the spike triggered average from the linear mean-evoked response function. These results provide a maximally tractable limiting case that complements and extends previous results obtained in the integrate and fire framework.

  8. Contrast polarity preservation's role in perception: explained and unexplained stimuli.

    Science.gov (United States)

    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.

  9. Characterization of Ferrofluid-based Stimuli-responsive Elastomers

    Directory of Open Access Journals (Sweden)

    Sandra dePedro

    2016-12-01

    Full Text Available Stimuli-responsive materials undergo physicochemical, and/or structural changes when a specific actuation is applied. They are heterogeneous composites, consisting of a non-responsive matrix where functionality is provided by the filler. Surprisingly, the synthesis of Polydimethylsiloxane (PDMS-based stimuli-responsive elastomers (SRE has seldomly been presented. Here we present the structural, biological, optical, magnetic and mechanical properties of several magnetic SRE (M-SRE obtained by combining PDMS and isoparafin-based ferrofluid (FF. Independently of the FF concentration, results shown a similar aggregation level, with the nanoparticles (NP mostly isolated (>60%. In addition to the superparamagnetic behaviour, the samples show no cytotoxicity except the sample with the highest FF concentration. Spectral response shows FF concentrations where both optical readout and magnetic actuation can simultaneously be used. The Young’s modulus increases with the FF concentration until the elastomeric network is distorted. Our results demonstrate that PDMS can host up to 24.6% FF. When applied to soft microsystems, a large displacement for relatively low magnetic fields (< 0.3 T is achieved. The herein presented M-SRE characterization can be used for a large number of disciplines where magnetic actuation can be combined with optical detection, mechanical elements and biological samples.

  10. Music Influences Ratings of the Affect of Visual Stimuli

    Directory of Open Access Journals (Sweden)

    Waldie E Hanser

    2013-09-01

    Full Text Available This review provides an overview of recent studies that have examined how music influences the judgment of emotional stimuli, including affective pictures and film clips. The relevant findings are incorporated within a broader theory of music and emotion, and suggestions for future research are offered.Music is important in our daily lives, and one of its primary uses by listeners is the active regulation of one's mood. Despite this widespread use as a regulator of mood and its general pervasiveness in our society, the number of studies investigating the issue of whether, and how, music affects mood and emotional behaviour is limited however. Experiments investigating the effects of music have generally focused on how the emotional valence of background music impacts how affective pictures and/or film clips are evaluated. These studies have demonstrated strong effects of music on the emotional judgment of such stimuli. Most studies have reported concurrent background music to enhance the emotional valence when music and pictures are emotionally congruent. On the other hand, when music and pictures are emotionally incongruent, the ratings of the affect of the pictures will in- or decrease depending on the emotional valence of the background music. These results appear to be consistent in studies investigating the effects of (background music.

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

    Science.gov (United States)

    Li, Guoqiang; Meng, Harper; Hu, Jinlian

    2012-12-07

    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.

  12. Task-irrelevant blindsight and the impact of invisible stimuli

    Directory of Open Access Journals (Sweden)

    Petra eStoerig

    2011-04-01

    Full Text Available Despite their subjective invisibility, stimuli presented within regions of absolute cortical blindness can both guide forced-choice behaviour when they are task-relevant and modulate responses to visible targets when they are task-irrelevant. We here tested three hemianopic patients to learn whether their performance in an attention-demanding rapid serial visual presentation task would be affected by task-irrelevant stimuli. Per trial, nine black letters and one white target-letter appeared briefly at fixation; the white letter was to be named at the end of each trial. On 50% of trials, a task-irrelevant disk (-.6 log contrast was presented to the blind field; in separate blocks, the same or a very low negative contrast distractor was presented to the sighted field. Mean error rates were high and independent of distractor condition, although the high contrast sighted-field disk impaired performance significantly in one participant. However, when trials with and without distractors were considered separately, performance was most impaired by the high contrast disk in the blind field, whereas the same disk in the sighted field had no effect. As this disk was least visible in the blind and most visible in the sighted field, attentional suppression was inversely related to visibility. We suggest that visual awareness, or the processes that generate it and are compromised in the blind hemisphere, enhances or enables effective attentional suppression.

  13. Task-irrelevant blindsight and the impact of invisible stimuli.

    Science.gov (United States)

    Stoerig, Petra

    2011-01-01

    Despite their subjective invisibility, stimuli presented within regions of absolute cortical blindness can both guide forced-choice behavior when they are task-relevant and modulate responses to visible targets when they are task-irrelevant. We here tested three hemianopic patients to learn whether their performance in an attention-demanding rapid serial visual presentation task would be affected by task-irrelevant stimuli. Per trial, nine black letters and one white target letter appeared briefly at fixation; the white letter was to be named at the end of each trial. On 50% of trials, a task-irrelevant disk (-0.6 log contrast) was presented to the blind field; in separate blocks, the same or a very low negative contrast distractor was presented to the sighted field. Mean error rates were high and independent of distractor condition, although the high-contrast sighted-field disk impaired performance significantly in one participant. However, when trials with and without distractors were considered separately, performance was most impaired by the high-contrast disk in the blind field, whereas the same disk in the sighted field had no effect. As this disk was least visible in the blind and most visible in the sighted field, attentional suppression was inversely related to visibility. We suggest that visual awareness, or the processes that generate it and are compromised in the blind hemisphere, enhances or enables effective attentional suppression.

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

    Science.gov (United States)

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. EEG Responses to Auditory Stimuli for Automatic Affect Recognition

    Science.gov (United States)

    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

  16. Pupillary response to direct and consensual chromatic light stimuli

    DEFF Research Database (Denmark)

    Traustason, Sindri; Brondsted, Adam Elias; Sander, Birgit

    2016-01-01

    PURPOSE: To assess whether the direct and consensual postillumination (ipRGC-driven) pupil light responses to chromatic light stimuli are equal in healthy subjects. METHODS: Pupil responses in healthy volunteers were recorded using a prototype binocular chromatic pupillometer (IdeaMedical, Copenh......PURPOSE: To assess whether the direct and consensual postillumination (ipRGC-driven) pupil light responses to chromatic light stimuli are equal in healthy subjects. METHODS: Pupil responses in healthy volunteers were recorded using a prototype binocular chromatic pupillometer (Idea......Medical, Copenhagen), which is capable of both direct and consensual pupillometry measurements. The device uses a pair of dual monochromatic narrow bandwidth LED light sources, red (660 nm) and blue (470 nm). Pupil light responses were recorded with infrared video cameras and analysed using custom-made circuitry...... was slightly larger during consensual illumination compared to direct illumination (0.54 and 0.52, respectively, p = 0.027, paired Wilcoxon's test, n = 12), while no differences were found for CAmax or the PIPR. CONCLUSIONS: No difference was found between direct and consensual pupil response to either red...

  17. Investigating vision in schizophrenia through responses to humorous stimuli

    Directory of Open Access Journals (Sweden)

    Wolfgang Tschacher

    2015-06-01

    Full Text Available The visual environment of humans contains abundant ambiguity and fragmentary information. Therefore, an early step of vision must disambiguate the incessant stream of information. Humorous stimuli produce a situation that is strikingly analogous to this process: Funniness is associated with the incongruity contained in a joke, pun, or cartoon. Like in vision in general, appreciating a visual pun as funny necessitates disambiguation of incongruous information. Therefore, perceived funniness of visual puns was implemented to study visual perception in a sample of 36 schizophrenia patients and 56 healthy control participants. We found that both visual incongruity and Theory of Mind (ToM content of the puns were associated with increased experienced funniness. This was significantly less so in participants with schizophrenia, consistent with the gestalt hypothesis of schizophrenia, which would predict compromised perceptual organization in patients. The association of incongruity with funniness was not mediated by known predictors of humor appreciation, such as affective state, depression, or extraversion. Patients with higher excitement symptoms and, at a trend level, reduced cognitive symptoms, reported lower funniness experiences. An open question remained whether patients showed this deficiency of visual incongruity detection independent of their ToM deficiency. Humorous stimuli may be viewed as a convenient method to study perceptual processes, but also fundamental questions of higher-level cognition.

  18. Moving stimuli facilitate synchronization but not temporal perception

    Directory of Open Access Journals (Sweden)

    Susana Silva

    2016-11-01

    Full Text Available Recent studies have shown that a moving visual stimulus (e.g., a bouncing ball facilitates synchronization compared to a static stimulus (e.g., a flashing light, and that it can even be as effective as an auditory beep. We asked a group of participants to perform different tasks with four stimulus types: beeps, siren-like sounds, visual flashes (static and bouncing balls. First, participants performed synchronization with isochronous sequences (stimulus-guided synchronization, followed by a continuation phase in which the stimulus was internally generated (imagery-guided synchronization. Then they performed a perception task, in which they judged whether the final part of a temporal sequence was compatible with the previous beat structure (stimulus-guided perception. Similar to synchronization, an imagery-guided variant was added, in which sequences contained a gap in between (imagery-guided perception. Balls outperformed flashes and matched beeps (powerful ball effect in stimulus-guided synchronization but not in perception (stimulus- or imagery-guided. In imagery-guided synchronization, performance accuracy decreased for beeps and balls, but not for flashes and sirens. Our findings suggest that the advantages of moving visual stimuli over static ones are grounded in action rather than perception, and they support the hypothesis that the sensorimotor coupling mechanisms for auditory (beeps and moving visual stimuli (bouncing balls overlap.

  19. Bimodal Stimuli Do Not Always Facilitate Infants' Rule Learning

    Directory of Open Access Journals (Sweden)

    Sin Mei Tsui

    2011-05-01

    Full Text Available Seven-month-old infants possess the ability to extract and generalize abstract rules from unimodal sequences of auditory syllables such as ABA and ABB whereas five-month-old infants are facilitated in their learning of these rules by bimodal sequences. In the current study, we investigated whether bimodal stimuli could also help infants acquire what we consider a more difficult abstract rule: AAB. Nineteen 8- to 9-month-old infants were habituated to the AAB rule with simultaneous visual shapes and speech sounds. They were later tested on their ability to discriminate this sequence from ABA and ABB with their looking times measured after each stimulus presentation at test periods. There was no significant difference in looking times amongst the different sequences, suggesting infants were not able to formulate an AAB rule different from those for ABA and ABB. Older infants' inability to utilize extra sensory information to acquire an abstract rule in which younger ones were ready to learn from unimodal stimulus (speech was unexpected. It is unclear what leads to the failure of rule learning from bimodal stimuli, but possible explanations including perceptual narrowing in the inter-sensory integration and the difference in sensory representation of abstract rules with different difficulties are discussed.

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

    Science.gov (United States)

    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.

  1. Physiological responses to social and nonsocial stimuli in neurotypical adults with high and low levels of autistic traits: implications for understanding nonsocial drive in autism spectrum disorders.

    Science.gov (United States)

    Singleton, Clarence J; Ashwin, Chris; Brosnan, Mark

    2014-12-01

    Researchers have suggested that the two primary cognitive features of autism spectrum disorder (ASD), a drive toward nonsocial processing and a reduced drive toward social processing, may be unrelated to each other in the neurotypical (NT) population and may therefore require separate explanations. Drive toward types of processing may be related to physiological arousal to categories of stimuli, such as social (e.g., faces) or nonsocial (e.g., trains). This study investigated how autistic traits in an NT population might relate to differences in physiological responses to nonsocial compared with social stimuli. NT participants were recruited to examine these differences in those with high vs. low degrees of ASD traits. Forty-six participants (21 male, 25 female) completed the Autism Spectrum Quotient (AQ) to measure ASD traits before viewing a series of 24 images while skin conductance response (SCR) was recorded. Images included six nonsocial, six social, six face-like cartoons, and six nonsocial (relating to participants' personal interests). Analysis revealed that those with a higher AQ had significantly greater SCR arousal to nonsocial stimuli than those with a low AQ, and the higher the AQ, the greater the difference between SCR arousal to nonsocial and social stimuli. This is the first study to identify the relationship between AQ and physiological response to nonsocial stimuli, and a relationship between physiological response to both social and nonsocial stimuli, suggesting that physiological response may underlie the atypical drive toward nonsocial processing seen in ASD, and that at the physiological level at least the social and nonsocial in ASD may be related to one another.

  2. Intact emotion facilitation for nonsocial stimuli in autism: is amygdala impairment in autism specific for social information?

    Science.gov (United States)

    South, Mikle; Ozonoff, Sally; Suchy, Yana; Kesner, Raymond P; McMahon, William M; Lainhart, Janet E

    2008-01-01

    Atypical amygdala development may play a key role in the emergence of social disability and other symptoms of autism (Baron-Cohen et al., 2000; Schultz, 2005). The mechanisms by which this may occur have received little attention, however, and most support from behavioral and imaging studies has been concerned with socially relevant stimuli such as faces. Given the complexity of amygdala function and its known role in many other emotional tasks, we examined whether individuals with autism would demonstrate impaired performance on several tasks that have been shown to require activation of the amygdala but that do not have any explicit social meaning. Relative to a typical comparison group matched for age and IQ, our sample of 37 adolescents and adults with autism (mean age=19.7 years) demonstrated equivalent facilitation for perception and learning of emotionally relevant stimuli. On each of four tasks, there were significant main effects of emotion condition on performance for both groups. Future research regarding atypical amygdala function and emotion processing in autism should consider whether the response to nonsocial emotion factors (including negative valence or high arousal) may be intact, despite difficulties in responding to socially relevant stimuli.

  3. Coupling of cerebral blood flow and oxygen metabolism is conserved for chromatic and luminance stimuli in human visual cortex.

    Science.gov (United States)

    Leontiev, Oleg; Buracas, Giedrius T; Liang, Christine; Ances, Beau M; Perthen, Joanna E; Shmuel, Amir; Buxton, Richard B

    2013-03-01

    The ratio of the changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) during brain activation is a critical determinant of the magnitude of the blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI). Cytochrome oxidase (CO), a key component of oxidative metabolism in the mitochondria, is non-uniformly distributed in visual area V1 in distinct blob and interblob regions, suggesting significant spatial variation in the capacity for oxygen metabolism. The goal of this study was to test whether CBF/CMRO(2) coupling differed when these subpopulations of neurons were preferentially stimulated, using chromatic and luminance stimuli to preferentially stimulate either the blob or interblob regions. A dual-echo spiral arterial spin labeling (ASL) technique was used to measure CBF and BOLD responses simultaneously in 7 healthy human subjects. When the stimulus contrast levels were adjusted to evoke similar CBF responses (mean 65.4% ± 19.0% and 64.6% ± 19.9%, respectively for chromatic and luminance contrast), the BOLD responses were remarkably similar (1.57% ± 0.39% and 1.59% ± 0.35%) for both types of stimuli. We conclude that CBF-CMRO(2) coupling is conserved for the chromatic and luminance stimuli used, suggesting a consistent coupling for blob and inter-blob neuronal populations despite the difference in CO concentration.

  4. The analysis of the influence of fractal structure of stimuli on fractal dynamics in fixational eye movements and EEG signal

    Science.gov (United States)

    Namazi, Hamidreza; Kulish, Vladimir V.; Akrami, Amin

    2016-01-01

    One of the major challenges in vision research is to analyze the effect of visual stimuli on human vision. However, no relationship has been yet discovered between the structure of the visual stimulus, and the structure of fixational eye movements. This study reveals the plasticity of human fixational eye movements in relation to the ‘complex’ visual stimulus. We demonstrated that the fractal temporal structure of visual dynamics shifts towards the fractal dynamics of the visual stimulus (image). The results showed that images with higher complexity (higher fractality) cause fixational eye movements with lower fractality. Considering the brain, as the main part of nervous system that is engaged in eye movements, we analyzed the governed Electroencephalogram (EEG) signal during fixation. We have found out that there is a coupling between fractality of image, EEG and fixational eye movements. The capability observed in this research can be further investigated and applied for treatment of different vision disorders. PMID:27217194

  5. The analysis of the influence of fractal structure of stimuli on fractal dynamics in fixational eye movements and EEG signal

    Science.gov (United States)

    Namazi, Hamidreza; Kulish, Vladimir V.; Akrami, Amin

    2016-05-01

    One of the major challenges in vision research is to analyze the effect of visual stimuli on human vision. However, no relationship has been yet discovered between the structure of the visual stimulus, and the structure of fixational eye movements. This study reveals the plasticity of human fixational eye movements in relation to the ‘complex’ visual stimulus. We demonstrated that the fractal temporal structure of visual dynamics shifts towards the fractal dynamics of the visual stimulus (image). The results showed that images with higher complexity (higher fractality) cause fixational eye movements with lower fractality. Considering the brain, as the main part of nervous system that is engaged in eye movements, we analyzed the governed Electroencephalogram (EEG) signal during fixation. We have found out that there is a coupling between fractality of image, EEG and fixational eye movements. The capability observed in this research can be further investigated and applied for treatment of different vision disorders.

  6. 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

    Science.gov (United States)

    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…

  7. 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

    Science.gov (United States)

    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…

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

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Skakkebæk, Anne; Bojesen, Anders

    2016-01-01

    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 r....... 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.......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...... 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...

  9. Stimuli-responsive PEGylated prodrugs for targeted doxorubicin delivery

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Minghui; Qian, Junmin, E-mail: jmqian@mail.xjtu.edu.cn; Liu, Xuefeng; Liu, Ting; Wang, Hongjie

    2015-05-01

    In recent years, stimuli-sensitive prodrugs have been extensively studied for the rapid “burst” release of antitumor drugs to enhance chemotherapeutic efficiency. In this study, a novel stimuli-sensitive prodrug containing galactosamine as a targeting moiety, poly(ethylene glycol)–doxorubicin (PEG–DOX) conjugate, was developed for targeting HepG2 human liver cancer cells. To obtain the PEG–DOX conjugate, both galactosamine-decorated poly(ethylene glycol) aldehyde (Gal-PEG-CHO) and methoxy poly(ethylene glycol) aldehyde (mPEG-CHO) were firstly synthesized and functionalized with dithiodipropionate dihydrazide (TPH) through direct reductive amination via Schiff's base formation, and then DOX molecules were chemically conjugated to the hydrazide end groups of TPH-functionalized Gal-/m-PEG chains via pH-sensitive hydrazone linkages. The chemical structures of TPH-functionalized PEG and PEG–DOX prodrug were confirmed by {sup 1}H NMR analysis. The PEG–DOX conjugate could self-assemble into spherical nanomicelles with a mean diameter of 140 nm, as indicated by transmission electron microscopy and dynamic light scattering. The drug loading content and loading efficiency in the prodrug nanomicelles were as high as 20 wt.% and 75 wt.%, respectively. In vitro drug release studies showed that DOX was released rapidly from the prodrug nanomicelles at the intracellular levels of pH and reducing agent. Cellular uptake and MTT experiments demonstrated that the galactosamine-decorated prodrug nanomicelles were more efficiently internalized into HepG2 cells via a receptor-mediated endocytosis process and exhibited a higher toxicity, compared with pristine prodrug nanomicelles. These results suggest that the novel Gal-PEG–DOX prodrug nanomicelles have tremendous potential for targeted liver cancer therapy. - Highlights: • A novel stimuli-responsive PEGylated prodrugs is synthesized. • PEGylated prodrugs can self-assemble into spherical nanoparticles (140 nm

  10. PREFACE: Stimuli Stimuli

    Science.gov (United States)

    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 well-rehearsed talk. The audience was intrigued by this new principle of stimulated coherent microwave radiation [3]. Friedrich Hund, famous for his 'rule' was then our theory professor, he sat in the second row. He was very surprised, and asked me in the discussion if he had understood correctly. If it were true what I had just suggested, then the maser coherence length would go from the Earth to the Moon. I paused a little, pondered and observed my microwave-conscious friends in the audience nodding encouragingly. 'Yes, sir; I think so!' 'I don't believe it', Hund retorted. How could a youngster react? I remained silent and obediently, quite imperceptibly shrugged my shoulders. After the talk, Professor Lamla, an editor of a science journal came to congratulate me and asked for a manuscript. I delivered [4]. This item on my early publication list may have contributed to the fact that I was hired in 1959 by William Shockley to join his fledgling company Shockley Transistor in this old apricot barn on 391 South San Antonio Road in Mountain View, California [5]. I knew that it would be extremely difficult to extend the frequency into the optical regime, you have to fight against the square of the frequency. Nevertheless, I refrained from making the statement in my paper that reaching an optical maser might be hopeless [4]. 'Never say never' is an appropriate adage, not only for seniors. A young colleague, who had also written a review paper, dared to support a more pessimistic view [6]. He anticipated in his very last sentence that stimulated emission would probably prevail merely in the microwave regime. This defeatist attitude seemed to have ruled throughout Germany, as already preached in the famous textbooks by Pohl [7], and also assumed by physics Professor Hellwege at Darmstadt, who was the leading expert regarding luminescence of materials such as ruby crystals; yet Maiman and others surpassed him [8]. Silicon came next for me, working, for example, with Shockley on the theory of maximal efficiency for solar cells, not really a topic regarding coherent radiation [9]. Once, however, a discussion evolved during one of those nearly dreaded hamburger lunches with Shockley at Kirk's charcoal restaurant on El Camino Real in Mountain View. Those frugal lunches ended with a demanding one-on-one interrogation, stricter and tougher than any doctoral oral examination. 'What, you do not know of Einstein's A and B coefficients?' Next afternoon I dutifully looked them up in the Stanford physics library. My first, rather indirect contacts with semiconductor heterojunctions occurred in this former apricot barn of Shockley's. Improving junction transistors required a maximum of the emitter efficiency. The emitter-to-base junction should carry only a forward current, no particles should flow from base to emitter [10]. This requirement can be met with a heterojunction: some other semiconductor material covering the silicon. Shockley had already contemplated this possibility while still at Bell Laboratories [11]. One day, a physicist by the name of Herbert Krömer visited us. This young man had also studied at Göttingen, especially with the memorable theoretician Richard Becker, whom we all admired. Krömer had in Princeton contributed to the theoretical understanding [12] of such wide-gap emitter/base junctions, and Shockley urgently wanted to hire him. But Herb preferred to join Varian Associates, just up the road in Palo Alto. Later, it was my great pleasure to attend the Nobel Festivities for Herb and Zhores Alferov in Stockholm. In the early sixties, I became a Member of Technical Staff at the Bell Laboratories in Murray Hill, New Jersey. Now, compound semiconductors, such as gallium arsenide, had to attract my interest. By the time of the mid-sixties, helium/neon-lasers were quite the vogue; Bell Labs actually established a little workshop with a production line to fabricate them and spread them throughout the departments. 'The solution in search of a problem', as sceptics joked about this new light source, was of vital interest to us because of the high frequencies to carry plenty of information channels. Transmission of laser light straight through the air, from Building 1 to Building 2 at Murray Hill, however, showed that the atmosphere was by far too unstable. We discussed silver-plated tubes and glass fibers, which eventually became so unbelievably pure that nowadays they provide a wealth of inexpensive communication channels. A gas laser did not appear to emerge into a viable, convenient engineering solution, nor did the ruby. A diode laser source had to be developed. I used laser-induced photoluminescence to search for more efficient GaAs materials, which resulted in detecting crystals with amphoteric silicon doping of very high output in the near-infrared [13]. This invention was patented in 37 countries and provided millions of diodes, such as for TV remote control devices. I had to sign off my inventor's reward for one US dollar, which I actually did not even receive. (In earlier years, patentors obtained one silver dollar; but not anymore!) Yet my little diodes, however efficient, could not be stimulated to emit coherent light, alas! Together with my colleagues and friends Morton Panish and Craig Casey, later famous textbook authors on diode lasers [14], we searched for solutions, although colleagues at the famed RCA Laboratories in Princeton had predicted that a laser diode was impossible [15]. I remember one morning when Mort told us of a talk he had just heard at a meeting in New York City, where our friendly competitors at the IBM Labs in Yorktown Heights, NY had suggested that heterojunctions could nicely confine and concentrate carriers, maybe also photons. Such heterojunctions were then tried in Panish's lab to be grown via liquid-phase epitaxy, Stan Sumski being the expert technician. At that time, the Leningraders, under leadership of Zhores Alferov were working hard and highly successfully with this crystal growth technique. We were very much impressed by the success in Leningrad. Liquid-phase epitaxy yields, in principle, exceedingly pure crystals, but we were unhappy about the principal lack of direct monitoring during this growth process, which we deemed absolutely necessary for obtaining reproducible heterojunctions with tightly controlled small dimensions. Ultrahigh-vacuum epitaxy seemed to be the inescapable solution. Delicate molecular beams had to be gently used and monitored! What a costly proposition! I clearly remember the day when Mort and I went to the Laboratory director John Galt. A little bit fearful and subdued, we explained our project. No, not expensive, rather a very expensive idea! We anxiously watched John with his usual stern demeanour; he paused and contemplated: 'All right, we do it—go ahead!' Construction for equipment needed for the Molecular Beam Epitaxy (MBE) began, and in Al Cho, an excellent new employee was hired for this task. A little later I left Bell Labs, this fabulous 'Mecca of Solid State' for a physics professorship at the Goethe University in Frankfurt-on-the-Main in Germany. Meanwhile, successful work on semiconductor lasers bore ample fruit worldwide. In Frankfurt, I used gas laser sources for photoluminescence diagnostics of elemental and compound semiconductors. With my astute doctoral student 'Teddy' Güttler, for example, we observed impurity photoluminescence in Au-doped silicon and concluded that doping of solar cells with deep impurities would not be beneficial for cell efficiency; just the opposite would happen because of increased carrier recombination [16]. In 1968, Western Germany experienced an ultra-left-wing student rebellion. Frankfurt students violently attacked me and accused me of war research since I used lasers, obviously a deadly weapon of mass destruction. Dieter Bimberg, our co-editor of this Festschrift, will undoubtedly remember those happenings when he was a doctoral candidate. In 1968, we all assembled in Moscow for the International Conference on the Physics of Semiconductors; what a unique opportunity to meet so many Russian colleagues, including this intellectual elite from the most remarkable Joffe Institute, with Zhores Alferov a major player. In 1970, I became a founding director of the Max-Planck-Institute for Solid State Research at Stuttgart, in the Southwest of Germany. There I eventually succeeded—against massive opposition—to establish a group for MBE, which became truly successful under the very capable leadership of Klaus Ploog [17], to whom was bestowed a prize of the Seibold-Foundation for Japan-Germany Science Cooperation. Klaus von Klitzing's group in our Max-Planck-Institute in Stuttgart relies on MBE to the present day for research on the quantum Hall effect [18]. Equally, my former doctoral student Horst Stormer had to utilize excellent MBE for his Nobel-Prize winning research on the fractional quantum Hall effect [18]. We fondly remember one congenial dinner party at our Stuttgart house, with Zhores Alferov and Helmut Lotsch as our valued guests; it must have been in the mid-seventies. My wife Inge had prepared a dessert in the shape of the title page of the Springer journal Applied Physics, with chocolate and orange cream. Herr Lotsch had won Alferov to become part of our board of editors, a most valuable connection to the excellence of Soviet semiconductor research! Many Japanese colleagues, especially from industrial electronics labs came to learn the tricks of MBE from us in Stuttgart; the German electronics industry, however, was reluctant and remained completely disinterested—but the French equipment maker RIBER was our staunch ally, and this company grew with the international acceptance of MBE for small, high-frequency devices. One diligent young visitor at my Stuttgart laboratories, Ozamu Kumagai from the SONY Corporation, did especially well. Back at home, he most cleverly devised novel technologies for efficient and low-cost production of laser diodes and thus earned a promotion to Vice Presidency. One of the most recent, gratifying encounters with Zhores Alferov happened to me in a cozy retreat in the forests near Madrid, with Antonio Luque being our gracious host for a solar cell symposium. We Stuttgarters had hoped to use multi-pair generation in perfected silicon solar cells [19], but a better chance to capture more photons from the solar spectrum exists most likely in multi-junction cells [20], with fancy tunnel-contacts interconnecting between heterojunctions. We shall see if this approach might eventually lead to more efficient, yet still economical solar energy conversion. Semiconductor heterojunctions for communications and consumers! Many of Alferov's present activities in St Petersburg and Berlin are governed by this magic modern prefix nano, which might one day also provide some applications in solar cells; but we have yet to carefully investigate [21]! References [1] Queisser H J 1958 Z.Physik 152 507 and 495 [2] Buckel W and Hilsch R 1956 Z. Physik 146 27 [3] Wittke J P 1957 Proc. IRE 45 291 with references to earlier work [4] Queisser H J 1959 Naturwiss. 46 394 [5] Queisser H J 1988 The Conquest of the Microchip (Cambridge, MA: Harvard University Press) [6] Wolf H C and Agnew Z 1958 Physik 10 480 [7] Pohl R W Optik (Heidelberg: Springer) [8] Yariv A 1968 Quantum Electronics (New York: Wiley) [9] Shockley W and Queisser H J 1961 J. Appl. Phys. 32 510 [10] For details, see Sze S M and Ng K K 2007 Physics of Semiconductor Devices 3rd edn (Hoboken, NJ: Wiley) [11] Shockley W 1951 US Patent Specification 2.569.347 [12] Krömer H 1957 Proc. IRE 45 1535 [13] Queisser H J 1966 J. Appl. Phys. 37 2909 (this paper was withheld internally for some time due to the patent application: US Pat.3.387.163) [14] Panish M B and Casey C H 1978 Heterostructure Lasers (New York: Academic) [15] Kressel H Private communications [16] Güttler G and Queisser H J 1996 J. Appl. Phys. 40 4994 [17] Ploog K and Graf K 1984 MBE of III-V Compounds (Berlin: Springer) [18] For recent coverage, see Chakraborty T and Pietiläinen P 1995 The Quantum Hall Effect (Berlin: Springer) [19] Werner J H, Kolodinski S and Queisser H J 1993 Phys. Rev. Lett. 72 3851 [20] Yamaguchi M 2002 Physica E 14 84 [21] Queisser H J 2002 Physica E 14 1 and many other contributions in this issue

  11. Brain processing of visual stimuli representing sexual penetration versus core and animal-reminder disgust in women with lifelong vaginismus.

    Directory of Open Access Journals (Sweden)

    Charmaine Borg

    Full Text Available It has been proposed that disgust evolved to protect humans from contamination. Through eliciting the overwhelming urge to withdraw from the disgusting stimuli, it would facilitate avoidance of contact with pathogens. The physical proximity implied in sexual intercourse provides ample opportunity for contamination and may thus set the stage for eliciting pathogen disgust. Building on this, it has been argued that the involuntary muscle contraction characteristic of vaginismus (i.e., inability to have vaginal penetration may be elicited by the prospect of penetration by potential contaminants. To further investigate this disgust-based interpretation of vaginismus (in DSM-5 classified as a Genito-Pelvic Pain/Penetration Disorder, GPPPD we used functional magnetic resonance imaging (fMRI to examine if women with vaginismus (n = 21 show relatively strong convergence in their brain responses towards sexual penetration- and disgust-related pictures compared to sexually asymptomatic women (n = 21 and women suffering from vulvar pain (dyspareunia/also classified as GPPPD in the DSM-5, n = 21. At the subjective level, both clinical groups rated penetration stimuli as more disgusting than asymptomatic women. However, the brain responses to penetration stimuli did not differ between groups. In addition, there was considerable conjoint brain activity in response to penetration and disgust pictures, which yield for both animal-reminder (e.g., mutilation and core (e.g., rotten food disgust domains. However, this overlap in brain activation was similar for all groups. A possible explanation for the lack of vaginismus-specific brain responses lies in the alleged female ambiguity (procreation/pleasure vs. contamination/disgust toward penetration: generally in women a (default disgust response tendency may prevail in the absence of sexual readiness. Accordingly, a critical next step would be to examine the processing of penetration stimuli following

  12. The relativity of time perception produced by facial emotion stimuli.

    Science.gov (United States)

    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.

  13. Stimuli-Directed Helical Chirality Inversion and Bio-Applications

    Directory of Open Access Journals (Sweden)

    Ziyu Lv

    2016-08-01

    Full Text Available Helical structure is a sophisticated ubiquitous motif found in nature, in artificial polymers, and in supramolecular assemblies from microscopic to macroscopic points of view. Significant progress has been made in the synthesis and structural elucidation of helical polymers, nevertheless, a new direction for helical polymeric materials, is how to design smart systems with controllable helical chirality, and further use them to develop chiral functional materials and promote their applications in biology, biochemistry, medicine, and nanotechnology fields. This review summarizes the recent progress in the development of high-performance systems with tunable helical chirality on receiving external stimuli and discusses advances in their applications as drug delivery vesicles, sensors, molecular switches, and liquid crystals. Challenges and opportunities in this emerging area are also presented in the conclusion.

  14. Balancing Attended and Global Stimuli in Perceived Video Quality Assessment

    DEFF Research Database (Denmark)

    You, Junyong; Korhonen, Jari; Perkis, Andrew

    2011-01-01

    The visual attention mechanism plays a key role in the human perception system and it has a significant impact on our assessment of perceived video quality. In spite of receiving less attention from the viewers, unattended stimuli can still contribute to the understanding of the visual content....... This paper proposes a quality model based on the late attention selection theory, assuming that the video quality is perceived via two mechanisms: global and local quality assessment. First we model several visual features influencing the visual attention in quality assessment scenarios to derive...... an attention map using appropriate fusion techniques. The global quality assessment as based on the assumption that viewers allocate their attention equally to the entire visual scene, is modeled by four carefully designed quality features. By employing these same quality features, the local quality model...

  15. Executive control suppresses pupillary responses to aversive stimuli.

    Science.gov (United States)

    Cohen, Noga; Moyal, Natali; Henik, Avishai

    2015-12-01

    Adaptive behavior depends on the ability to effectively regulate emotional responses. Continuous failure in the regulation of emotions can lead to heightened physiological reactions and to various psychopathologies. Recently, several behavioral and neuroimaging studies showed that exertion of executive control modulates emotion. Executive control is a high-order operation involved in goal-directed behavior, especially in the face of distractors or temptations. However, the role of executive control in regulating emotion-related physiological reactions is unknown. Here we show that exercise of executive control modulates reactivity of both the sympathetic and the parasympathetic components of the autonomic nervous system. Specifically, we demonstrate that both pupillary light reflex and pupil dilation for aversive stimuli are attenuated following recruitment of executive control. These findings offer new insights into the very basic mechanisms of emotion processing and regulation, and can lead to novel interventions for people suffering from emotion dysregulation psychopathologies. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Discrimination of facial appearance stimuli in body dysmorphic disorder.

    Science.gov (United States)

    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.

  17. Stimuli Responsive Ionogels for Sensing Applications—An Overview

    Directory of Open Access Journals (Sweden)

    Andrew Kavanagh

    2012-02-01

    Full Text Available 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.

  18. Sleep deprivation affects reactivity to positive but not negative stimuli.

    Science.gov (United States)

    Pilcher, June J; Callan, Christina; Posey, J Laura

    2015-12-01

    The current study examined the effects of partial and total sleep deprivation on emotional reactivity. Twenty-eight partially sleep-deprived participants and 31 totally sleep-deprived participants rated their valence and arousal responses to positive and negative pictures across four testing sessions during the day following partial sleep deprivation or during the night under total sleep deprivation. The results suggest that valence and arousal ratings decreased under both sleep deprivation conditions. In addition, partial and total sleep deprivation had a greater negative effect on positive events than negative events. These results suggest that sleep-deprived persons are more likely to respond less to positive events than negative events. One explanation for the current findings is that negative events could elicit more attentive behavior and thus stable responding under sleep deprivation conditions. As such, sleep deprivation could impact reactivity to emotional stimuli through automated attentional and self-regulatory processes. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Dinoflagellate bioluminescence in response to mechanical stimuli in water flows

    Directory of Open Access Journals (Sweden)

    A. S. Cussatlegras

    2005-01-01

    Full Text Available 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.

  20. Stimuli-sensitive hydrogels for pharmaceutical and medical applications

    Directory of Open Access Journals (Sweden)

    Ilić-Stojanović Snežana

    2011-01-01

    Full Text Available Hydrogels are three-dimensional cross-linked hydrophilic polymers that swell in water and aqueous solutions without dissolving in them. They are very sensitive to environmental stimulus, which is manifested by a sharp phase transition. This feature is important for their application in the pharmaceutical field, especially for making formulations with controlled release of active ingredients, with the correction of the solubility, degradation and their toxicity reducing. Because of the compatibility with living tissues, hydrogels can be used in different medical purposes (for making contact lenses, stents, balloon catheters, artificial muscles, substitutes for arteries and veins, trachea, oviduct. This work presents methods (chemical and physical for obtaining hydrogels, their properties and sensitivity to environmental stimuli (temperature, pH, magnetic field, as well as their potential application in medicine and pharmacy.

  1. What boxing-related stimuli reveal about response behaviour.

    Science.gov (United States)

    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.

  2. Separating in vivo mechanical stimuli for postpneumonectomy compensation: physiological assessment.

    Science.gov (United States)

    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.

  3. Perfusion-related stimuli for compensatory lung growth following pneumonectomy.

    Science.gov (United States)

    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.

  4. Reduced Interocular Transfer of Spatial Adaptation for Fast Stimuli

    Directory of Open Access Journals (Sweden)

    Daniel H Baker

    2012-05-01

    Full Text Available Threshold elevation following monocular adaptation is weaker in the unadapted eye than in the adapted eye. At least 15 studies have measured this interocular transfer (IOT phenomenon, and typically report around 60% transfer. Yet almost all of these studies used spatial frequencies above 3c/deg, very slow temporal parameters, and criterion sensitive methods (method of adjustment, yes/no. In recent work, we (Meese and Baker 2011, i-Perception 2 159–182 found markedly weaker interocular transfer at low spatial and high temporal frequencies. Here, we measure IOT in 9 observers for a broad range of spatiotemporal frequencies (0.5, 2, and 8c/deg; 1, 4, and 15Hz using a 2AFC paradigm. Targets were horizontal Gabor patches with a full-width-at-half height of 1.67 (lower frequencies or 6.68 (8c/deg grating cycles. Adaptors were larger gratings with the same spatiotemporal properties as the targets. Observers adapted for 2 min initially, and 5 s between each trial, with monocular presentation enabled by shutter goggles. We typically found weaker IOT than previously reported (<50%, particularly for our fastest stimuli (lowest spatial and highest temporal frequencies, where it was virtually absent in all cases. Binocular summation and monocular adaptation were normal in all conditions. This implies that adaptation to ‘magno’ stimuli, not investigated in previous studies, occurs at a monocular locus. We also consider possible methodological confounds in classical studies which might have inflated the levels of IOT. These include the formation of retinal afterimages from static adaptors and changes in criterion unrelated to changes in sensitivity.

  5. Alexithymia and automatic processing of emotional stimuli: a systematic review.

    Science.gov (United States)

    Donges, Uta-Susan; Suslow, Thomas

    2017-04-01

    Alexithymia is a personality trait characterized by difficulties in recognizing and verbalizing emotions and the utilization of a cognitive style that is oriented toward external events, rather than intrapsychic experiences. Alexithymia is considered a vulnerability factor influencing onset and course of many psychiatric disorders. Even though emotions are, in general, elicited involuntarily and emerge without conscious effort, it is surprising that little attention in etiological considerations concerning alexithymia has been given to deficits in automatic emotion processing and their neurobiological bases. In this article, results from studies using behavioral or neurobiological research methods were systematically reviewed in which automatic processing of external emotional information was investigated as a function of alexithymia in healthy individuals. Twenty-two studies were identified through a literature search of Psycinfo, PubMed, and Web of Science databases from 1990 to 2016. The review reveals deficits in the automatic processing of emotional stimuli in alexithymia at a behavioral and neurobiological level. The vast majority of the reviewed studies examined visual processing. The alexithymia facets externally oriented thinking and difficulties identifying feelings were found to be related to impairments in the automatic processing of threat-related facial expressions. Alexithymic individuals manifest low reactivity to barely visible negative emotional stimuli in brain regions responsible for appraisal, encoding, and affective response, e.g. amygdala, occipitotemporal areas, and insula. Against this background, it appears plausible to assume that deficits in automatic emotion processing could be factors contributing to alexithymic personality characteristics. Directions for future research on alexithymia and automatic emotion perception are suggested.

  6. Dopamine, paranormal belief, and the detection of meaningful stimuli.

    Science.gov (United States)

    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.

  7. Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

    Directory of Open Access Journals (Sweden)

    Singh Vinod

    2010-01-01

    Full Text Available Background: Stimuli-sensitive hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids on stimulation, such as pH, temperature and ionic change. Aim: To develop hydrogels that are sensitive to stimuli, i.e. pH, in the cul-de-sac of the eye for providing a prolonged effect and increased bioavailability with reduction in frequency of administration. Materials and Methods: Hydrogels were formulated by using timolol maleate as the model drug, polyacrylic acid as the gelling agents, hydroxyl ethyl cellulose as the viscolizer and sodium chloride as the isotonic agent. Stirring of ingredients in pH 4 phosphate buffer at high speed was carried out. The dynamic dialysis technique was used for drug release studies. In vivo study for reduction in intraocular pressure was carried out by using albino rabbits. Statistical Analysis: Drug release studies data were used for statistical analysis in first-order plots, Higuchi plots and Peppas exponential plots. Student t-test was performed for in vivo study. Results: Viscosity of the hydrogel increases from 3.84 cps to 9.54 cps due to change in pH 4 to pH 7.4. The slope value of the Peppas equation was found to be 0.3081, 0.3743 and 0.2964. Up to 80% of drug was released in an 8 h drug release study. Sterile hydrogels with no ocular irritation were obtained. Conclusions: Hydrogels show increase in viscosity due to change in pH. Hydrogels were therapeutically effacious, stable, non-irritant and showed Fickian diffusion. In vivo results clearly show a prolonged reduction in intraocular pressure, which was helpful for reduction in the frequency of administration.

  8. Acute stress-induced cortisol elevations mediate reward system activity during subconscious processing of sexual stimuli.

    Science.gov (United States)

    Oei, Nicole Y L; Both, Stephanie; van Heemst, Diana; van der Grond, Jeroen

    2014-01-01

    Stress is thought to alter motivational processes by increasing dopamine (DA) secretion in the brain's "reward system", and its key region, the nucleus accumbens (NAcc). However, stress studies using functional magnetic resonance imaging (fMRI), mainly found evidence for stress-induced decreases in NAcc responsiveness toward reward cues. Results from both animal and human PET studies indicate that the stress hormone cortisol may be crucial in the interaction between stress and dopaminergic actions. In the present study we therefore investigated whether cortisol mediated the effect of stress on DA-related responses to -subliminal-presentation of reward cues using the Trier Social Stress Test (TSST), which is known to reliably enhance cortisol levels. Young healthy males (n = 37) were randomly assigned to the TSST or control condition. After stress induction, brain activation was assessed using fMRI during a backward-masking paradigm in which potentially rewarding (sexual), emotionally negative and neutral stimuli were presented subliminally, masked by pictures of inanimate objects. A region of interest analysis showed that stress decreased activation in the NAcc in response to masked sexual cues (voxel-corrected, pcortisol levels were related to stronger NAcc activation, showing that cortisol acted as a suppressor variable in the negative relation between stress and NAcc activation. The present findings indicate that cortisol is crucially involved in the relation between stress and the responsiveness of the reward system. Although generally stress decreases activation in the NAcc in response to rewarding stimuli, high stress-induced cortisol levels suppress this relation, and are associated with stronger NAcc activation. Individuals with a high cortisol response to stress might on one hand be protected against reductions in reward sensitivity, which has been linked to anhedonia and depression, but they may ultimately be more vulnerable to increased reward

  9. Aberrant Processing of Deviant Stimuli in Schizophrenia Revealed by Fusion of FMRI and EEG Data.

    Science.gov (United States)

    Calhoun, Vd; Wu, L; Kiehl, Ka; Eichele, T; Pearlson, Gd

    2010-06-01

    BACKGROUND: Aberrant electrophysiological and hemodynamic processing of auditory oddball stimuli is among the most robustly documented findings in patients with schizophrenia. However, no study to date has directly examined linked patterns of electrical and hemodynamic differences in patients and controls. METHODS: In a recent paper we demonstrated a data-driven approach, joint independent component analysis (jICA) to fuse together functional magnetic resonance imaging (fMRI) and event-related potential (ERP) data and elucidated the chronometry of auditory oddball target detection in healthy control subjects. In this paper we extend our fusion method to identify specific differences in the neuronal chronometry of target detection for chronic schizophrenia patients compared to healthy controls. RESULTS: We found one linked source, consistent with the N2 response, known to be related to cognitive processing of deviant stimuli, spatially localized to bilateral fronto-temporal regions. This source showed significant between-group differences both in amplitude response and in the fMRI/ERP distribution pattern. These findings are consistent with previous work showing N2 amplitude and latency abnormalities in schizophrenia, and provide new information about the linkage between the two. CONCLUSIONS: In summary, we use a novel approach to isolate and identify a linked fMRI/ERP component which shows marked differences in chronic schizophrenia patients. We also demonstrate that jointly using both fMRI and ERP measures provides a fully picture of the underlying hemodynamic and electrical changes which are present in patients. Our approach also has broad applicability to other diseases such as autism, Alzheimer's disease, or bipolar disorder.

  10. Polychromatic SSVEP stimuli with subtle flickering adapted to brain-display interactions

    Science.gov (United States)

    Chien, Yu-Yi; Lin, Fang-Cheng; Zao, John K.; Chou, Ching-Chi; Huang, Yi-Pai; Kuo, Heng-Yuan; Wang, Yijun; Jung, Tzyy-Ping; Shieh, Han-Ping D.

    2017-02-01

    Objective. Interactive displays armed with natural user interfaces (NUIs) will likely lead the next breakthrough in consumer electronics, and brain-computer interfaces (BCIs) are often regarded as the ultimate NUI-enabling machines to respond to human emotions and mental states. Steady-state visual evoked potentials (SSVEPs) are a commonly used BCI modality due to the ease of detection and high information transfer rates. However, the presence of flickering stimuli may cause user discomfort and can even induce migraines and seizures. With the aim of designing visual stimuli that can be embedded into video images, this study developed a novel approach to induce detectable SSVEPs using a composition of red/green/blue flickering lights. Approach. Based on the opponent theory of colour vision, this study used 32 Hz/40 Hz rectangular red-green or red-blue LED light pulses with a 50% duty cycle, balanced/equal luminance and 0°/180° phase shifts as the stimulating light sources and tested their efficacy in producing SSVEP responses with high signal-to-noise ratios (SNRs) while reducing the perceived flickering sensation. Main results. The empirical results from ten healthy subjects showed that dual-colour lights flickering at 32 Hz/40 Hz with a 50% duty cycle and 180° phase shift achieved a greater than 90% detection accuracy with little or no flickering sensation. Significance. As a first step in developing an embedded SSVEP stimulus in commercial displays, this study provides a foundation for developing a combination of three primary colour flickering backlights with adjustable luminance proportions to create a subtle flickering polychromatic light that can elicit SSVEPs at the basic flickering frequency.

  11. Neuroplasticity Changes of Rat Brain by Musical Stimuli during Fetal Period

    Directory of Open Access Journals (Sweden)

    Siamak Sheikhi

    2015-01-01

    Full Text Available Objective: Fetal development of the central nervous system is an important and sensitive stage which is affected by many external and internal stimuli. This study aimed to investigate effect of musical stimuli on fetal rat brain. Materials and Methods: In this experimental study, twelve female Wistar rats were selected and evenly assigned to control and musical groups. The females were mated with a male rat of the same genotype. Musical group was exposed to classic music with 60 dB power for 90 minutes twice per day from 2nd to 20th day of gestation. The control rats were handled similar to the musical group, but were not exposed to music. Before parturition, all the dams were anesthetized, and their blood samples were obtained and used for corticosterone (COS measurement. They were transcardially perfused by electron microscope (EM fixative agent. The fetal brains were extracted intact and used for slice preparation. Horizontal slices were made for electron microscope preparation, and images were taken and analyzed in terms of cell density and morphological changes. Results: EM observation indicated significant morphological difference in cellular and intercellular spaces between the two groups. Music-treated fetuses had significantly higher cell density in parietal cortex and music-treated dams had lower COS level. Conclusion: It was concluded that prenatal music would have a great impact on neuroplasticity of fetal rat brain, at least indirectly. Although the rat fetuses cannot hear until birth, music-induced reduction in COS blood level of dams might be the reason for neuroplasticity of fetal brain.

  12. Emotional stimuli facilitate time perception in children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Nazari, Mohammad A; Mirloo, Mohammad M; Rezaei, Mazaher; Soltanlou, Mojtaba

    2016-08-27

    The aim of this study was to compare the effect of different emotional stimuli (neutral, positive, and negative) on time perception in children with attention-deficit/hyperactivity disorder (ADHD) and normal children in dual-task form. Five hundred and ninety-nine students from primary schools were randomly selected. The Conner's Teacher Rating Scale (CTRS) questionnaire was completed by teachers. A total of 100 children with a score above the cut-off point for the CTRS were further assessed using the Child Symptom Inventory-4 (CSI-4). A total of 34 children with ADHD and 31 controls completed an emotional time discrimination task in two blocks of 1000 and 2000 ms duration. Children were asked to compare three image groups: neutral with neutral, neutral with positive, and neutral with negative images. Children with ADHD had significantly better performance in the emotional time discrimination task across all conditions when compared with controls: On average, discrimination thresholds were approximately 35 ms shorter for the children with ADHD. Our results indicate that children with ADHD have higher sensitivity to time relative to controls in a situation in which they must distribute resources between temporal and emotional processing. On the basis of the interference effect and the working memory capacity hypothesis, this dividing of attention causes a decrease of time accuracy in normal children.

  13. Comparison of EEG propagation speeds under emotional stimuli on smartphone between the different anxiety states

    Directory of Open Access Journals (Sweden)

    Tetsuya eAsakawa

    2014-12-01

    Full Text Available The current study was evaluated difference anxiety states at information processing in the electroencephalography (EEG under emotional stimuli for smartphone. Twenty-three healthy subjects were assessed for their anxiety states using The State Trait Anxiety Inventory (STAI and divided to two groups: low anxiety (I, II or high anxiety (III and IV, V group. EEG was measured under emotionally audio-visual stimuli (resting and pleasant, unpleasant sessions and emotionally sentence stimuli (pleasant sentence, unpleasant sentence sessions using emotionally audio-visual stimuli and emotionally sentence stimuli and analyzed using propagation speed analysis. The propagation speed of the low anxiety group at medial coronal in resting stimuli for all time was higher than those of high anxiety group, and that of the low anxiety group at medial sagittal in unpleasant stimuli for 60-150 seconds and those in unpleasant stimuli for 0-30, 60-150 seconds was higher than those of high anxiety group. The propagation speed for 150 seconds of all stimuli in the low anxiety group had a significantly higher than propagation speed for that in the high anxiety group. These events suggest that information processes concerning the emotional stimuli in the brain is differ based on the anxiety state of the subject.

  14. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    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.

  15. Individual variation in habituation: behaviour over time toward different stimuli in threespine sticklebacks (Gasterosteus aculeatus)

    OpenAIRE

    Bell, Alison M.; Peeke, Harman V.S.

    2012-01-01

    Habituation, or the relatively permanent waning of a response as a result of repeated stimulation, is a form of behavioural plasticity that allows animals to filter out irrelevant stimuli and to focus selectively on important stimuli. Individuals that fail to habituate might be at a disadvantage if they continue to respond to irrelevant stimuli; therefore, habituation can have adaptive significance. In this study we compared rates of behaviour over time toward three different ecologically-rel...

  16. Transient rheology of stimuli responsive hydrogels: Integrating microrheology and microfluidics

    Science.gov (United States)

    Sato, Jun

    Stimuli-responsive hydrogels have diverse potential applications in the field of drug delivery, tissue engineering, agriculture, cosmetics, gene therapy, and as sensors and actuators due to their unique responsiveness to external signals, such as pH, temperature, and ionic strength. Understanding the responsiveness of hydrogel structure and rheology to these stimuli is essential for designing materials with desirable performance. However, no instrumentation and well-defined methodology are available to characterize the structural and rheological responses to rapid solvent changes. In this thesis, a new microrheology set-up is described, which allows us to quantitatively measure the transient rheological properties and microstructure of a variety of solvent-responsive complex fluids. The device was constructed by integrating particle tracking microrheology and microfluidics and offers unique experimental capabilities for performing solvent-reponse measurements on soft fragile materials without applying external shear forces. Transient analysis methods to quantitatively obtain rheological properties were also constructed, and guidelines for the trade-off between statistical validity and temporal resolution were developed to accurately capture physical transitions. Employing the new device and methodology, we successfully quantified the transient rheological and microstructural responses during gel formation and break-up, and viscosity changes of solvent-responsive complex fluids. The analysis method was expanded for heterogeneous samples, incorporating methods to quantify the microrheology of samples with broad distributions of individual particle dynamics. Transient microrheology measurements of fragile, heterogeneous, self-assembled block copolypeptide hydrogels revealed that solvent exchange via convective mixing and dialysis can lead to significantly different gel properties and that commonly applied sample preparation protocols for the characterization of soft

  17. Evaluative conditioning of high-novelty stimuli does not seem to be based on an automatic form of associative learning

    NARCIS (Netherlands)

    Dedonder, Jonathan; Corneille, Olivier; Yzerbyt, Vincent; Kuppens, Toon

    2010-01-01

    Evaluative conditioning (EC) refers to the change in valence of initially neutral stimuli (conditioned stimuli, or CSs) as a result of their pairing with positive or negative stimuli (unconditioned stimuli, or USs). EC is critical to dual-attitudes models as it is often presented as an evaluative

  18. Evaluative conditioning of high-novelty stimuli does not seem to be based on an automatic form of associative learning

    NARCIS (Netherlands)

    Dedonder, Jonathan; Corneille, Olivier; Yzerbyt, Vincent; Kuppens, Toon

    2010-01-01

    Evaluative conditioning (EC) refers to the change in valence of initially neutral stimuli (conditioned stimuli, or CSs) as a result of their pairing with positive or negative stimuli (unconditioned stimuli, or USs). EC is critical to dual-attitudes models as it is often presented as an evaluative ef

  19. The use of faces as stimuli in neuroimaging and psychological experiments: a procedure to standardize stimulus features.

    Science.gov (United States)

    Gronenschild, Ed H B M; Smeets, Floortje; Vuurman, Eric F P M; van Boxtel, Martin P J; Jolles, Jelle

    2009-11-01

    In psychological experiments involving facial stimuli, it is of great importance that the basic perceptual or psychological characteristics that are investigated are not confounded by factors such as brightness and contrast, head size, hair cut and color, skin color, and the presence of glasses and earrings. Standardization of facial stimulus materials reduces the effect of these confounding factors. We therefore employed a set of basic image processing techniques to deal with this issue. The processed images depict the faces in grayscale, all at the same size, brightness, and contrast, and confined to an oval mask revealing only the basic features such as the eyes, nose, and mouth. The standardization was successfully applied to four different face databases, consisting of male and female faces and including neutral as well as happy facial expressions. An important advantage of the proposed standardization is that featural as well as configurational information is retained. We also consider the procedure to be a major contribution to the development of a de facto standard for the use of facial stimuli in psychological experiments. Such methodological standardization would allow a better comparison of the results of these studies.

  20. Recognition of face and non-face stimuli in autistic spectrum disorder.

    Science.gov (United States)

    Arkush, Leo; Smith-Collins, Adam P R; Fiorentini, Chiara; Skuse, David H

    2013-12-01

    The ability to remember faces is critical for the development of social competence. From childhood to adulthood, we acquire a high level of expertise in the recognition of facial images, and neural processes become dedicated to sustaining competence. Many people with autism spectrum disorder (ASD) have poor face recognition memory; changes in hairstyle or other non-facial features in an otherwise familiar person affect their recollection skills. The observation implies that they may not use the configuration of the inner face to achieve memory competence, but bolster performance in other ways. We aimed to test this hypothesis by comparing the performance of a group of high-functioning unmedicated adolescents with ASD and a matched control group on a "surprise" face recognition memory task. We compared their memory for unfamiliar faces with their memory for images of houses. To evaluate the role that is played by peripheral cues in assisting recognition memory, we cropped both sets of pictures, retaining only the most salient central features. ASD adolescents had poorer recognition memory for faces than typical controls, but their recognition memory for houses was unimpaired. Cropping images of faces did not disproportionately influence their recall accuracy, relative to controls. House recognition skills (cropped and uncropped) were similar in both groups. In the ASD group only, performance on both sets of task was closely correlated, implying that memory for faces and other complex pictorial stimuli is achieved by domain-general (non-dedicated) cognitive mechanisms. Adolescents with ASD apparently do not use domain-specialized processing of inner facial cues to support face recognition memory.

  1. Interictal neurocognitive processing of visual stimuli in migraine: evidence from event-related potentials.

    Directory of Open Access Journals (Sweden)

    Marla J S Mickleborough

    Full Text Available Research has established decreased sensory habituation as a defining feature in migraine, while decreased cognitive habituation has only been found with regard to cognitive assessment of the relative probability of the occurrence of a stimulus event. Our study extended the investigation of interictal habituation in migraine to include cognitive processing when viewing of a series of visually-complex images, similar to those we encounter on the internet everyday. We examined interictal neurocognitive function in migraine from a habituation perspective, using a novel paradigm designed to assess how the response to a series of images changes over time. Two groups of participants--migraineurs (N = 25 and non-migraine controls (N = 25--were asked to view a set of 232 unfamiliar logos in the context of a target identification task as their brain electrical responses were recorded via event-related potentials (ERPs. The set of logos was viewed serially in each of 10 separate trial blocks, with data analysis focusing on how the ERP responses to the logos in frontal electrodes from 200-600 ms changed across time within each group. For the controls, we found that the amplitude of the late positive potential (LPP ERP component elicited by the logos had no significant change across trial blocks. In contrast, in migraineurs we found that the LPP significantly increased in amplitude across trial blocks, an effect consistent with a lack of habituation to visual stimuli seen in previous research. Our findings provide empirical support abnormal cognitive processing of complex visual images across time in migraineurs that goes beyond the sensory-level habituation found in previous research.

  2. Social facilitation of insect reproduction with motor-driven tactile stimuli

    National Research Council Canada - National Science Library

    Uzsák, Adrienn; Dieffenderfer, James; Bozkurt, Alper; Schal, Coby

    2014-01-01

    ..., and thermo-, hygro- and mechanoreception. The antennae, being the anteriormost sensory appendages, play a prominent role in social interactions with conspecifics that involve primarily chemosensory and tactile stimuli...

  3. The Occurrence Rate of the Fission Illusion Differs Depending on the Complexity of Visual Stimuli

    Directory of Open Access Journals (Sweden)

    Yasuhiro Takeshima

    2011-10-01

    Full Text Available A fission illusion (also named a double—flash illusion is a famous phenomenon of audio-visual interaction, in which a single brief flash is perceived as two flashes when presented simultaneously with two brief beeps (Shames, Kamitani, & Shimojo, 2000; 2002. The fission illusion has been investigated using relatively simple visual stimuli like single circle. Thus the illusion has not been examined by using complex visual stimuli. Markovic & Gvozdenovic (2001 reported that the processing of complex visual stimuli tends to be delayed. Therefore, the complexity of visual stimuli may affect the occurrence rate of the fission illusion, since this illusion is generated in the process that copes with visual and auditory stimuli in a short time. The present study examined the differences in illusory occurrence rates by manipulating the complexity of visual stimuli. We used the patterns proposed by Garner & Clement (1963 to control the complexity. The results indicated that it was more difficult to induce the fission illusion by using complex visual stimuli than it was by using simple stimuli. Thus, the present study suggested that the occurrence rate of the fission illusion differed depending on the perceptual efficiency in the coding process of visual stimuli. This study was supported by Grant-in-Aid for Specifically Promoted Research (No. 19001004.

  4. Alleged Approach-Avoidance Conflict for Food Stimuli in Binge Eating Disorder.

    Directory of Open Access Journals (Sweden)

    Elisabeth J Leehr

    Full Text Available 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.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.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.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.

  5. Event-related potentials when identifying or color-naming threatening schematic stimuli in spider phobic and non-phobic individuals

    OpenAIRE

    Musial Frauke; Kolassa Iris-Tatjana; Kolassa Stephan; Miltner Wolfgang HR

    2006-01-01

    Abstract Background Previous studies revealed increased parietal late positive potentials (LPPs) in response to spider pictures in spider phobic individuals. This study searched for basic features of fear-relevant stimuli by investigating whether schematic spider images are sufficient to evoke differential behavioral as well as differential early and late ERP responses in spider phobic, social phobic (as a clinical control group), and non-phobic control participants. Methods Behavioral and el...

  6. Event-related potentials when identifying or color-naming threatening schematic stimuli in spider phobic and non-phobic individuals

    Directory of Open Access Journals (Sweden)

    Musial Frauke

    2006-09-01

    Full Text Available Abstract Background Previous studies revealed increased parietal late positive potentials (LPPs in response to spider pictures in spider phobic individuals. This study searched for basic features of fear-relevant stimuli by investigating whether schematic spider images are sufficient to evoke differential behavioral as well as differential early and late ERP responses in spider phobic, social phobic (as a clinical control group, and non-phobic control participants. Methods Behavioral and electrophysiological correlates of the processing of schematic spider and flower images were investigated while participants performed a color (emotional Stroop and an object identification task. Stimuli were schematic pictures of spiders and flowers matched with respect to constituting visual elements. Results Consistent with previous studies using photographic spider pictures, spider phobic persons showed enhanced LPPs when identifying schematic spiders compared to schematic flowers. In addition, spider phobic individuals showed generally faster responses than the control groups. This effect was interpreted as evidence for an increased general behavioral hypervigilance in this anxiety disorder group. Furthermore, both phobic groups showed enhanced P100 amplitudes compared to controls, which was interpreted as evidence for an increased (cortical hypervigilance for incoming stimuli in phobic patients in general. Finally, all groups showed faster identification of and larger N170 amplitudes in response to schematic spider than flower pictures. This may reflect either a general advantage for fear-relevant compared to neutral stimuli, or might be due to a higher level of expertise in processing schematic spiders as compared to the more artificially looking flower stimuli. Conclusion Results suggest that schematic spiders are sufficient to prompt differential responses in spider-fearful and spider-non-fearful persons in late ERP components. Early ERP components, on

  7. IMAGES, IMAGES, IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, A.

    1980-07-01

    The role of images of information (charts, diagrams, maps, and symbols) for effective presentation of facts and concepts is expanding dramatically because of advances in computer graphics technology, increasingly hetero-lingual, hetero-cultural world target populations of information providers, the urgent need to convey more efficiently vast amounts of information, the broadening population of (non-expert) computer users, the decrease of available time for reading texts and for decision making, and the general level of literacy. A coalition of visual performance experts, human engineering specialists, computer scientists, and graphic designers/artists is required to resolve human factors aspects of images of information. The need for, nature of, and benefits of interdisciplinary effort are discussed. The results of an interdisciplinary collaboration are demonstrated in a product for visualizing complex information about global energy interdependence. An invited panel will respond to the presentation.

  8. Differences in cortical response to acupressure and electroacupuncture stimuli

    Directory of Open Access Journals (Sweden)

    Vangel Mark G

    2011-07-01

    Full Text Available Abstract Background FMRI studies focus on sub-cortical effects of acupuncture stimuli. The purpose of this study was to assess changes in primary somatosensory (S1 activity over the course of different types of acupuncture stimulation. We used whole head magnetoencephalography (MEG to map S1 brain response during 15 minutes of electroacupuncture (EA and acupressure (AP. We further assessed how brain response changed during the course of stimulation. Results Evoked brain response to EA differed from AP in its temporal dynamics by showing clear contralateral M20/M30 peaks while the latter demonstrated temporal dispersion. Both EA and AP demonstrated significantly decreased response amplitudes following five minutes of stimulation. However, the latency of these decreases were earlier in EA (~30 ms post-stimulus than AP (> 100 ms. Time-frequency responses demonstrated early onset, event related synchronization (ERS, within the gamma band at ~70-130 ms and the theta band at ~50-200 ms post-stimulus. A prolonged event related desynchronization (ERD of alpha and beta power occurred at ~100-300 ms post-stimulus. There was decreased beta ERD at ~100-300 ms over the course of EA, but not AP. Conclusion Both EA and AP demonstrated conditioning of SI response. In conjunction with their subcortical effects on endogenous pain regulation, these therapies show potential for affecting S1 processing and possibly altering maladaptive neuroplasticity. Thus, further investigation in neuropathic populations is needed.

  9. Pattern transformations in periodic cellular solids under external stimuli

    Science.gov (United States)

    Zhang, K.; Zhao, X. W.; Duan, H. L.; Karihaloo, B. L.; Wang, J.

    2011-04-01

    The structural patterns of periodic cellular materials play an important role in their properties. Here, we investigate how these patterns transform dramatically under external stimuli in simple periodic cellular structures that include a nanotube bundle and a millimeter-size plastic straw bundle. Under gradual hydrostatic straining up to 20%, the cross-section of the single walled carbon nanotube bundle undergoes several pattern transformations, while an amazing new hexagram pattern is triggered from the circular shape when the strain of 20% is applied suddenly in one step. Similar to the nanotube bundle, the circular plastic straw bundle is transformed into a hexagonal pattern on heating by conduction through a baseplate but into a hexagram pattern when heated by convection. Besides the well-known elastic buckling, we find other mechanisms of pattern transformation at different scales; these include the minimization of the surface energy at the macroscale or of the van der Waals energy at the nanoscale and the competition between the elastic energy of deformation and either the surface energy at the macroscale or the van der Waals energy at the nanoscale. The studies of the pattern transformations of periodic porous materials offer new insights into the fabrication of novel materials and devices with tailored properties.

  10. Exogenous (automatic) attention to emotional stimuli: a review.

    Science.gov (United States)

    Carretié, Luis

    2014-12-01

    Current knowledge on the architecture of exogenous attention (also called automatic, bottom-up, or stimulus-driven attention, among other terms) has been mainly obtained from studies employing neutral, anodyne stimuli. Since, from an evolutionary perspective, exogenous attention can be understood as an adaptive tool for rapidly detecting salient events, reorienting processing resources to them, and enhancing processing mechanisms, emotional events (which are, by definition, salient for the individual) would seem crucial to a comprehensive understanding of this process. This review, focusing on the visual modality, describes 55 experiments in which both emotional and neutral irrelevant distractors are presented at the same time as ongoing task targets. Qualitative and, when possible, meta-analytic descriptions of results are provided. The most conspicuous result is that, as confirmed by behavioral and/or neural indices, emotional distractors capture exogenous attention to a significantly greater extent than do neutral distractors. The modulatory effects of the nature of distractors capturing attention, of the ongoing task characteristics, and of individual differences, previously proposed as mediating factors, are also described. Additionally, studies reviewed here provide temporal and spatial information-partially absent in traditional cognitive models-on the neural basis of preattention/evaluation, reorienting, and sensory amplification, the main subprocesses involved in exogenous attention. A model integrating these different levels of information is proposed. The present review, which reveals that there are several key issues for which experimental data are surprisingly scarce, confirms the relevance of including emotional distractors in studies on exogenous attention.

  11. Olfactory classical conditioning in neonatal mouse pups using thermal stimuli.

    Science.gov (United States)

    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.

  12. Characterization of functional biopolymers under various external stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Maleki, Atoosa

    2008-07-01

    Polymers are large molecules composed of repeating structural units connected by covalent chemical bonds. Biopolymers are a class of polymers produced by living organisms, which exhibit both biocompatible and biodegradable properties. The behavior of a biopolymer in solution is strongly dependent on the chemical and physical structure of the polymer chain, as well as external environmental conditions. To improve biopolymers in the direction of higher performance and better functionality, understanding of their physicochemical behavior and their response to external stimuli are of great importance. Rheology, rheo-small angle light scattering, dynamic light scattering, small angle neutron scattering, and asymmetric flow field-flow fractionation were utilized in this thesis to investigate the properties of hydroxyethyl cellulose and its hydrophobically modified analogue, as well as dextran, hyaluronan, and mucin under different conditions such as temperature, solvent, mechanical stress and strain, and radiation. Different novel hydrogels were prepared by using various chemical cross-linking agents. Specific features of these macromolecules provide them to be used as 'functional' materials, e.g., sensors, actuators, personal care products, enhanced oil recovery, and controlled drug delivery systems (author)

  13. Peculiarities of hearing impairment depending on interaction with acoustic stimuli

    Science.gov (United States)

    Myshchenko, Iryna; Nazarenko, Vasyl; Kolganov, Anatoliy; Tereshchenko, Pavlo

    2015-01-01

    Aims: The functional state of the auditory analyzer of several operators groups was study. The objective of this study was to determine some characteristics of hearing impairment in relation with features of acoustic stimuli and informative significance of noise. Materials and Methods: 236 employees (middle age 35.4 ± 0.74 years) were divided into four groups according to features of noise perception at the workplaces. The levels of permanent shifts of acoustic thresholds were estimated using audiometric method. Statistical Analysis Used: Common statistical methods were used in research. Mean quantity and mean absolute errors were calculated. Statistical significance between operators' groups was calculated with 0.05 confidential intervals. Results: The peculiarities of hearing impairment in observed groups were different. Operators differentiating acoustic signals had peak of hearing impairment in the field of language frequencies, while the employees who work with noise background at the workplaces had maximal hearing threshold on the 4000 Hz frequency (P ≤ 0.05). Conclusions: Hearing impairment depends both on energy and human interaction with acoustic irritant. The distinctions in hearing impairment may be related with the necessity of recognizing of acoustic signals and their frequency characteristics. PMID:26957812

  14. Objective perimetry in glaucoma: recent advances with multifocal stimuli.

    Science.gov (United States)

    Graham, S L; Klistorner, A; Grigg, J R; Billson, F A

    1999-06-01

    The introduction of multifocal stimulus recording has enhanced our ability to examine the human visual field with electrophysiologic techniques. We have adapted the multifocal pattern visual evoked potential (PVEP) to detect visual field loss. In glaucoma patients we sought to determine the extent to which the PVEP amplitudes correlate with perimetric thresholds. Multifocal pseudorandomly alternated pattern stimuli, which were cortically scaled in size, were presented with use of the VERIS-Scientific system. Bipolar occipital straddle electrode positions were used. The visual field up to 25 degrees of eccentricity was investigated. Forty-three glaucoma patients with reproducible visual field defects were tested. The bipolar PVEP corresponded well with Humphrey visual field defects, showing loss of signal in the scotoma area. For Humphrey quadrant threshold totals and PVEP quadrant amplitudes, the correlation coefficient was strong (r = 0.49, P < 0.0001). The multifocal PVEP demonstrates good correspondence with the topography of the visual field. This technique represents the first practical application of the multifocal PVEP to objective detection of visual field defects in glaucoma.

  15. Undetected changes in visible stimuli influence subsequent decisions.

    Science.gov (United States)

    Laloyaux, Cédric; Devue, Christel; Doyen, Stéphane; David, Elodie; Cleeremans, Axel

    2008-09-01

    Change blindness-our inability to detect changes in a stimulus-occurs even when the change takes place gradually, without any disruption [Simons, D. J., Franconeri, S. L., & Reimer, R. L. (2000). Change blindness in the absence of a visual disruption. Perception, 29(10), 1143-1154]. Such gradual changes are more difficult to detect than changes that involve a disruption. Using this method, David et al. [David, E., Laloyaux, C., Devue, C., & Cleeremans, A. (in press). Change blindness to gradual changes in facial expressions. Psychologica Belgica] recently showed substantial blindness to changes that involve facial expressions of emotion. In this experiment, we show that people who failed to detect any change in the displays were (1) nevertheless influenced by the changing information in subsequent recognition decisions about which facial expression they had seen, and (2) that their confidence in their decisions was lower after exposure to changing vs. static displays. The findings therefore support the notion that undetected changes that occur in highly salient stimuli may be causally efficacious and influence subsequent behavior. Implications concerning the nature of the representations associated with undetected changes are discussed.

  16. Satellite cell activity, without expansion, after nonhypertrophic stimuli.

    Science.gov (United States)

    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.

  17. The neural response to maternal stimuli: an ERP study.

    Science.gov (United States)

    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.

  18. Visual anticipatory information modulates multisensory interactions of artificial audiovisual stimuli.

    Science.gov (United States)

    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.

  19. External stimuli mediate collective rhythms: artificial control strategies.

    Directory of Open Access Journals (Sweden)

    Tianshou Zhou

    Full Text Available The artificial intervention of biological rhythms remains an exciting challenge. Here, we proposed artificial control strategies that were developed to mediate the collective rhythms emerging in multicellular structures. Based on noisy repressilators and by injecting a periodic control amount to the extracellular medium, we introduced two typical kinds of control models. In one, there are information exchanges among cells, where signaling molecules receive the injected stimulus that freely diffuses toward/from the intercellular medium. In the other, there is no information exchange among cells, but signaling molecules also receive the stimulus that directionally diffuses into each cell from the common environment. We uncovered physical mechanisms for how the stimulus induces, enhances or ruins collective rhythms. We found that only when the extrinsic period is close to an integer multiplicity of the averaged intrinsic period can the collective behaviors be induced/enhanced; otherwise, the stimulus possibly ruins the achieved collective behaviors. Such entrainment properties of these oscillators to external signals would be exploited by realistic living cells to sense external signals. Our results not only provide a new perspective to the understanding of the interplays between extrinsic stimuli and intrinsic physiological rhythms, but also would lead to the development of medical therapies or devices.

  20. Impaired autonomic responses to emotional stimuli in autoimmune limbic encephalitis

    Directory of Open Access Journals (Sweden)

    Olga eSchröder

    2015-11-01

    Full Text Available 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.

  1. Procedure to validate sexual stimuli: reliability and validity of a set of sexual stimuli in a sample of young colombian heterosexual males

    OpenAIRE

    Pablo Vallejo-Medina; Franklin Soler; Mayra, Gomez-Lugo; Alejandro, Saavedra-Roa; Laurent, Marchal-Bertrand

    2017-01-01

    Penile plethysmography – or phallometric assessment – is a very relevant evaluation for sexual health. The objective of this research is to suggest a guideline to validate sexual stimuli and validate a set of sexual stimuli to assess “normative” sexual behavior in Colombian young heterosexual men. Six videos of 3:15 minute-long were used. A total of 24 men were assessed. Objective sexual arousal, the International Index of Erectile Function-5, Self-Assessment Manikin, Multidimensi...

  2. Effects of affective pictures on pain sensitivity and cortical responses induced by laser stimuli in healthy subjects and migraine patients.

    Science.gov (United States)

    de Tommaso, Marina; Calabrese, Rita; Vecchio, Eleonora; De Vito Francesco, Vito; Lancioni, Giulio; Livrea, Paolo

    2009-11-01

    Visually induced analgesia has been correlated with the affective content of pleasant, neutral or unpleasant pictures. The aim of the present study was to assess the effect of affective images vision on laser evoked potentials and pain perception, in a cohort of healthy subjects and migraine patients. Twenty-two healthy subjects and 24 migraine without aura patients (recorded during the inter-critical phase) participated in the study. Eighty-four colour slides, arranged in two blocks, each consisting of 14 pleasant, 14 unpleasant and 14 neutral images, in random presentation, were chosen from the International Affective Picture System. The CO(2) laser stimuli were delivered on the dorsum of the right hand and supra-orbital zone at 7.5-watt intensity and 25-ms duration, in basal condition and during the viewing of affective pictures. Migraine patients expressed higher scores of valence and arousal for pleasant and unpleasant pictures, compared to controls. In both groups, a late positive potential in the 400-700 ms time range was clear for pleasant and unpleasant pictures, but its amplitude was significantly reduced in migraine patients. The pain rating and the N2 component were reduced in both groups during the visual task compared to basal condition. In migraineurs and controls the P2 wave was reduced during the vision of pleasant pictures, compared to basal condition. This indicates that stimulation by images with different affective content reduces subjective pain for a cognitive mechanism of attentive engagement, while a special inhibition of later LEPs is produced by a positive emotional impact. In migraine, affective images are able to modulate pain perception and LEPs, differently from other modalities of distraction, suggesting a possible emotive elaboration of painful stimuli.

  3. Real-time noninvasive optical imaging of exercising muscle and brain upon cognitive stimuli

    Science.gov (United States)

    Quaresima, Valentina; van der Sluijs, Marco C.; Menssen, Jan; Grillotti, Lucia; Ferrari, Marco; Colier, Willy N.

    2001-06-01

    The monitoring of a single muscle location does not reflect the heterogeneity of the muscle groups activation during exercise. In the past, measurements of oxygen consumption (VO2) at single muscle locations could be carried out non-invasively by near-infrared continuous wave spectroscopy (NIRCWS) at rest or during isometric contractions. In the present study, human regional quadriceps (vastus lateralis and rectus femoris) VO2 was investigated at rest and during maximal voluntary contractions using a 12- channel NIRCWS system with an acquisition time of 0.1 s.

  4. Presentation of Aural Stimuli to Newborns and Premature Infants: An Audiological Perspective.

    Science.gov (United States)

    Cassidy

    1999-01-01

    The purpose of this study was twofold: (a) to examine extant research in the field of music with premature and full term infants in order to identify protocols being used in the presentation of musical stimuli to neonates and (b) to use knowledge gleaned from audiology as a basis for suggesting a standardized protocol for use of musical stimuli with infants. Articles considered appropriate for inclusion in the analysis met the following criteria: (a) presented data for the effects of music on a dependent measure, (b) had subjects who were identified as either premature or term newborns receiving treatment after birth and prior to discharge from the hospital, and (c) used music for some or all of the aural stimuli. Articles (N = 20) were categorized by demographic information, types of aural stimuli, independent variables, dependent measures, and protocol used to present the musical stimuli. Of primary importance to this study was the protocol used in each study to present musical stimuli. Data regarding total duration of stimuli per day, longest duration of stimuli per day, method of stimuli presentation, placement of speakers, decibel level of stimuli, and where;he decibel level was measured reveal that there is no standard protocol being followed with regard to the presentation of aural stimuli. Recommendations include future research on (a) determining a minimum gestational age where music therapy may be appropriate, (b) determining the frequency spectrum perceived by a premature infant, (c) determining the decibel levels reaching the ear drum and assessing appropriate levels for minimum stimulation with maximum results, and (d) carefully considering the method of stimulus presentation as it will have an impact on the decibel level reaching the ear drum of these infants.

  5. Altered processing of rewarding and aversive basic taste stimuli in symptomatic women with anorexia nervosa and bulimia nervosa: An fMRI study.

    Science.gov (United States)

    Monteleone, Alessio Maria; Monteleone, Palmiero; Esposito, Fabrizio; Prinster, Anna; Volpe, Umberto; Cantone, Elena; Pellegrino, Francesca; Canna, Antonietta; Milano, Walter; Aiello, Marco; Di Salle, Francesco; Maj, Mario

    2017-02-21

    Functional magnetic resonance imaging (fMRI) studies have displayed a dysregulation in the way in which the brain processes pleasant taste stimuli in patients with anorexia nervosa (AN) and bulimia nervosa (BN). However, exactly how the brain processes disgusting basic taste stimuli has never been investigated, even though disgust plays a role in food intake modulation and AN and BN patients exhibit high disgust sensitivity. Therefore, we investigated the activation of brain areas following the administration of pleasant and aversive basic taste stimuli in symptomatic AN and BN patients compared to healthy subjects. Twenty underweight AN women, 20 symptomatic BN women and 20 healthy women underwent fMRI while tasting 0.292 M sucrose solution (sweet taste), 0.5 mM quinine hydrochloride solution (bitter taste) and water as a reference taste. In symptomatic AN and BN patients the pleasant sweet stimulus induced a higher activation in several brain areas than that induced by the aversive bitter taste. The opposite occurred in healthy controls. Moreover, compared to healthy controls, AN patients showed a decreased response to the bitter stimulus in the right amygdala and left anterior cingulate cortex, while BN patients showed a decreased response to the bitter stimulus in the right amygdala and left insula. These results show an altered processing of rewarding and aversive taste stimuli in ED patients, which may be relevant for understanding the pathophysiology of AN and BN.

  6. Regional cerebral changes and functional connectivity during the observation of negative emotional stimuli in subjects with post-traumatic stress disorder.

    Science.gov (United States)

    Mazza, Monica; Tempesta, Daniela; Pino, Maria Chiara; Catalucci, Alessia; Gallucci, Massimo; Ferrara, Michele

    2013-10-01

    Patients with post-traumatic stress disorder (PTSD) exhibit exaggerated brain responses to emotionally negative stimuli. Identifying the neural correlates of emotion regulation in these subjects is important for elucidating the neural circuitry involved in emotional dysfunction. The aim of this study was to investigate the functional connectivity between the areas activated during emotional processing of negative stimuli in a sample of individuals affected by PTSD compared to a group of healthy subjects. Ten subjects with PTSD (who survived the L'Aquila 2009 earthquake) and ten healthy controls underwent fMRI during which the participants observed 80 images: 40 pictures with negative emotional valence and 40 neutral (scrambled) stimuli. A higher activation was found in the left posterior (LP) insula for PTSD group and in the ventromedial prefrontal cortex (vmPFC) for the healthy group. Two sets of Granger causality modeling analyses were performed to examine the directed influence from LP-insula and vmPFC to other brain regions. Activity in the vmPFC in the healthy group while observing negative stimuli predicted activity in several subcortical regions and insula, while in the PTSD group the LP-insula exerted a positive directed influence on several cortical regions. The hyperactivation in PTSD subjects of subcortical areas such as the insula would underlie the emotional, social, and relational difficulties of PTSD patients.

  7. Vergence and accommodation to multiple-image-plane stereoscopic displays: 'Real world' responses with practical image-plane separations?

    Science.gov (United States)

    MacKenzie, K. J.; Dickson, R. A.; Watt, S. J.

    2011-03-01

    Conventional stereoscopic displays present images on a single focal plane. The resulting mismatch between the stimuli to the eyes' focusing response (accommodation) and to convergence causes fatigue and poor stereo performance. One promising solution is to distribute image intensity across a number of relatively widely spaced image planes - a technique referred to as depth filtering. Previously, we found this elicits accurate, continuous monocular accommodation responses with image-plane separations as large as 1.1 Diopters, suggesting that a relatively small (i.e. practical) number of image planes is sufficient to eliminate vergence-accommodation conflicts over a large range of simulated distances. However, accommodation responses have been found to overshoot systematically when the same stimuli are viewed binocularly. Here, we examined the minimum image-plane spacing required for accurate accommodation to binocular depth-filtered images. We compared accommodation and vergence responses to step changes in depth for depth-filtered stimuli, using image-plane separations of 0.6-1.2 D, and equivalent real stimuli. Accommodation responses to real and depth-filtered stimuli were equivalent for image-plane separations of ~0.6-0.9 D, but inaccurate thereafter. We conclude that depth filtering can be used to precisely match accommodation and vergence demand in a practical stereoscopic display, using a relatively small number of image planes.

  8. Specificity of brain reactions to second-order visual stimuli.

    Science.gov (United States)

    Babenko, Vitaly V; Ermakov, Pavel N

    2015-01-01

    The second-order visual mechanisms perform the operation of integrating the spatially distributed local visual information. Their organization is traditionally considered within the framework of the filter-rectify-filter model. These are the second-order filters that provide the ability to detect texture gradients. However, the question of the mechanisms' selectivity to the modulation dimension remains open. The aim of this investigation is to answer the above question by using visual evoked potentials (VEPs). Stimuli were textures consisting of staggered Gabor patches. The base texture was nonmodulated (NM). Three other textures represented the base texture which was sinusoidally modulated in different dimensions: contrast, orientation, or spatial frequency. EEG was recorded with 20 electrodes. VEPs of 500 ms duration were obtained for each of the four textures. After that, VEP to the NM texture was subtracted from VEP to each modulated texture. As a result, three different waves (d-waves) were obtained for each electrode site. Each d-wave was then averaged across all the 48 observers. The revealed d-waves have a latency of about 200 ms and, in our opinion, reflect the second-order filters reactivation through the feedback connection. The d-waves for different modulation dimensions were compared with each other in time, amplitude, topography, and localization of the sources of activity that causes the d-wave (with sLORETA). We proceeded from the assumption that the d-wave (its first component) represents functioning of the second-order visual mechanisms and activity changes at the following processing stages. It was found that the d-waves for different modulation dimensions significantly differ in all parameters. The obtained results indicate that the spatial modulations of different texture parameters caused specific changes in the brain activity, which could be evidence supporting the specificity of the second-order visual mechanisms to modulation dimension.

  9. Design, challenge, and promise of stimuli-responsive nanoantibiotics

    Science.gov (United States)

    Edson, Julius A.; Kwon, Young Jik

    2016-10-01

    Over the past few years, there have been calls for novel antimicrobials to combat the rise of drug-resistant bacteria. While some promising new discoveries have met this call, it is not nearly enough. The major problem is that although these new promising antimicrobials serve as a short-term solution, they lack the potential to provide a long-term solution. The conventional method of creating new antibiotics relies heavily on the discovery of an antimicrobial compound from another microbe. This paradigm of development is flawed due to the fact that microbes can easily transfer a resistant mechanism if faced with an environmental pressure. Furthermore, there has been some evidence to indicate that the environment of the microbe can provide a hint as to their virulence. Because of this, the use of materials with antimicrobial properties has been garnering interest. Nanoantibiotics, (nAbts), provide a new way to circumvent the current paradigm of antimicrobial discovery and presents a novel mechanism of attack not found in microbes yet; which may lead to a longer-term solution against drug-resistance formation. This allows for environment-specific activation and efficacy of the nAbts but may also open up and create new design methods for various applications. These nAbts provide promise, but there is still ample work to be done in their development. This review looks at possible ways of improving and optimizing nAbts by making them stimuli-responsive, then consider the challenges ahead, and industrial applications.[Figure not available: see fulltext.

  10. Category Variability Effect in Category Learning with Auditory Stimuli

    Directory of Open Access Journals (Sweden)

    Lee-Xieng eYang

    2014-10-01

    Full Text Available The category variability effect refers to that people tend to classify the midpoint item between two categories as the category more variable. This effect is regarded as evidence against the exemplar model, such as GCM (Generalized Context Model and favoring the rule model, such as GRT (i.e., the decision bound model. Although this effect has been found in conceptual category learning, it is not often observed in perceptual category learning. To figure out why the category variability effect is seldom reported in the past studies, we propose two hypotheses. First, due to sequence effect, the midpoint item would be classified as different categories, when following different items. When we combine these inconsistent responses for the midpoint item, no category variability effect occurs. Second, instead of the combination of sequence effect in different categorization conditions, the combination of different categorization strategies conceals the category variability effect. One experiment is conducted with single tones of different frequencies as stimuli. The collected data reveal sequence effect. However, the modeling results with the MAC model and the decision bound model support that the existence of individual differences is the reason for why no category variability effect occurs. Three groups are identified by their categorization strategy. Group 1 is rule user, placing the category boundary close to the low-variability category, hence inducing category variability effect. Group 2 takes the MAC strategy and classifies the midpoint item as different categories, depending on its preceding item. Group 3 classifies the midpoint item as the low-variability category, which is consistent with the prediction of the decision bound model as well as GCM. Nonetheless, our conclusion is that category variability effect can be found in perceptual category learning, but might be concealed by the averaged data.

  11. Multiple distinct stimuli increase measured nucleosome occupancy around human promoters.

    Directory of Open Access Journals (Sweden)

    Chuong D Pham

    Full Text Available Nucleosomes can block access to transcription factors. Thus the precise localization of nucleosomes relative to transcription start sites and other factor binding sites is expected to be a critical component of transcriptional regulation. Recently developed microarray approaches have allowed the rapid mapping of nucleosome positions over hundreds of kilobases (kb of human genomic DNA, although these approaches have not yet been widely used to measure chromatin changes associated with changes in transcription. Here, we use custom tiling microarrays to reveal changes in nucleosome positions and abundance that occur when hormone-bound glucocorticoid receptor (GR binds to sites near target gene promoters in human osteosarcoma cells. The most striking change is an increase in measured nucleosome occupancy at sites spanning ∼1 kb upstream and downstream of transcription start sites, which occurs one hour after addition of hormone, but is lost at 4 hours. Unexpectedly, this increase was seen both on GR-regulated and GR-non-regulated genes. In addition, the human SWI/SNF chromatin remodeling factor (a GR co-activator was found to be important for increased occupancy upon hormone treatment and also for low nucleosome occupancy without hormone. Most surprisingly, similar increases in nucleosome occupancy were also seen on both regulated and non-regulated promoters during differentiation of human myeloid leukemia cells and upon activation of human CD4+ T-cells. These results indicate that dramatic changes in chromatin structure over ∼2 kb of human promoters may occur genomewide and in response to a variety of stimuli, and suggest novel models for transcriptional regulation.

  12. Design, challenge, and promise of stimuli-responsive nanoantibiotics.

    Science.gov (United States)

    Edson, Julius A; Kwon, Young Jik

    2016-01-01

    Over the past few years, there have been calls for novel antimicrobials to combat the rise of drug-resistant bacteria. While some promising new discoveries have met this call, it is not nearly enough. The major problem is that although these new promising antimicrobials serve as a short-term solution, they lack the potential to provide a long-term solution. The conventional method of creating new antibiotics relies heavily on the discovery of an antimicrobial compound from another microbe. This paradigm of development is flawed due to the fact that microbes can easily transfer a resistant mechanism if faced with an environmental pressure. Furthermore, there has been some evidence to indicate that the environment of the microbe can provide a hint as to their virulence. Because of this, the use of materials with antimicrobial properties has been garnering interest. Nanoantibiotics, (nAbts), provide a new way to circumvent the current paradigm of antimicrobial discovery and presents a novel mechanism of attack not found in microbes yet; which may lead to a longer-term solution against drug-resistance formation. This allows for environment-specific activation and efficacy of the nAbts but may also open up and create new design methods for various applications. These nAbts provide promise, but there is still ample work to be done in their development. This review looks at possible ways of improving and optimizing nAbts by making them stimuli-responsive, then consider the challenges ahead, and industrial applications.Graphical abstractA graphic detailing how the current paradigm of antibiotic discovery can be circumvented by the use of nanoantibiotics.

  13. Stimuli-Responsive, Shape-Transforming Nanostructured Particles.

    Science.gov (United States)

    Lee, Junhyuk; Ku, Kang Hee; Kim, Mingoo; Shin, Jae Man; Han, Junghun; Park, Chan Ho; Yi, Gi-Ra; Jang, Se Gyu; Kim, Bumjoon J

    2017-08-01

    Development of particles that change shape in response to external stimuli has been a long-thought goal for producing bioinspired, smart materials. Herein, the temperature-driven transformation of the shape and morphology of polymer particles composed of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers (BCPs) and temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) surfactants is reported. PNIPAM acts as a temperature-responsive surfactant with two important roles. First, PNIPAM stabilizes oil-in-water droplets as a P4VP-selective surfactant, creating a nearly neutral interface between the PS and P4VP domains together with cetyltrimethylammonium bromide, a PS-selective surfactant, to form anisotropic PS-b-P4VP particles (i.e., convex lenses and ellipsoids). More importantly, the temperature-directed positioning of PNIPAM depending on its solubility determines the overall particle shape. Ellipsoidal particles are produced above the critical temperature, whereas convex lens-shaped particles are obtained below the critical temperature. Interestingly, given that the temperature at which particle shape change occurs depends solely on the lower critical solution temperature (LCST) of the polymer surfactants, facile tuning of the transition temperature is realized by employing other PNIPAM derivatives with different LCSTs. Furthermore, reversible transformations between different shapes of PS-b-P4VP particles are successfully demonstrated using a solvent-adsorption annealing with chloroform, suggesting great promise of these particles for sensing, smart coating, and drug delivery applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Autonomous adrenocorticotropin reaction to stress stimuli in human fetus.

    Science.gov (United States)

    Kosinska-Kaczynska, Katarzyna; Bartkowiak, Robert; Kaczynski, Bartosz; Szymusik, Iwona; Wielgos, Miroslaw

    2012-04-01

    The aim of the study was to determine whether human fetuses show ACTH response to stress stimuli, to define the gestational age from which these reactions may be present and to analyze the relationship between hormone concentrations and their changes, both in fetuses and in pregnant women. The study included 81 intrauterine transfusions carried out in 19 pregnant women. 52 procedures were performed directly into the umbilical vein, which is not innervated, so neutral for the fetus (the PCI group) and 29 transfusions into the intrahepatic vein -which puncture is stressful for the fetus (the IHV group). ACTH and cortisol concentrations in fetal and maternal plasma obtained during the procedures were assayed. The initial mean plasma ACTH concentration in the PCI group equaled 18.94pg/mL, but in the IHV group it was significantly higher and amounted 75.17pg/mL (p0.05) and in the PCI group (22.36pg/mL, p>0.05). The observed hormonal response in the IHV group proves the existence of fetal pituitary reaction to stress. The initial fetal ACTH concentration in the IHV group correlated with the number of transfusions performed on a single fetus (R=0.41; p=0.04). No correlation with parity, gestational weeks or the volume of transfused packed red blood cells was found. There was also no correlation between fetal and maternal ACTH concentrations in any group. Presented data suggest that the human fetus shows autonomous ACTH reaction to stress stimulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Resistance to Change and Frequency of Response-Dependent Stimuli Uncorrelated with Reinforcement

    Science.gov (United States)

    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. Long-latency auditory evoked potentials with verbal and nonverbal stimuli,

    Directory of Open Access Journals (Sweden)

    Sheila Jacques Oppitz

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. OBJECTIVE: To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. METHODS: A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000 Hz - frequent and 4000 Hz - rare; and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare. RESULTS: Considering the component N2 for tone burst, the lowest latency found was 217.45 ms for the BA/DI stimulus; the highest latency found was 256.5 ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340 ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. CONCLUSION: There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude.

  17. Natural stimuli improve auditory BCIs with respect to ergonomics and performance

    Science.gov (United States)

    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.

  18. Rescuing Stimuli from Invisibility: Inducing a Momentary Release from Visual Masking with Pre-Target Entrainment

    Science.gov (United States)

    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…

  19. Stimuli for municipal responses to climate adaptation: insights from Philadelphia – an early adapter

    NARCIS (Netherlands)

    Uittenbroek, C.J.; Janssen-Jansen, Leonie; Runhaar, H.A.C.

    2016-01-01

    An in-depth understanding of these stimuli is currently lacking in literature as most research has focussed on overcoming barriers to climate adaptation. The aim of this paper is to identify stimuli for municipal responses to climate adaptation and examine how they influence the governance approach

  20. Brief report: Inhibitory control of socially relevant stimuli in children with high functioning autism

    NARCIS (Netherlands)

    Geurts, H.M.; Begeer, S.; Stockman, L.

    2009-01-01

    The current study explored whether inhibitory control deficits in high functioning autism (HFA) emerged when socially relevant stimuli were used and whether arousal level affected the performance. A Go/NoGo paradigm, with socially relevant stimuli and varying presentation rates, was applied in 18 ch

  1. Stimuli for municipal responses to climate adaptation: insights from Philadelphia – an early adapter

    NARCIS (Netherlands)

    Uittenbroek, C.J.; Janssen-Jansen, Leonie; Runhaar, H.A.C.

    2016-01-01

    An in-depth understanding of these stimuli is currently lacking in literature as most research has focussed on overcoming barriers to climate adaptation. The aim of this paper is to identify stimuli for municipal responses to climate adaptation and examine how they influence the governance approach

  2. The Magnitude of Perceptual Learning is Equated when Stimuli are Scaled According to Cortical Magnification Factor

    Directory of Open Access Journals (Sweden)

    Andrew T Astle

    2012-05-01

    Full Text Available Practice helps improve performance on a variety of visual tasks. Previous studies have shown that the magnitude of these improvements is inversely proportional to initial levels of performance, with subjects who perform more poorly at the start tending to improve most during perceptual training. If initial performance levels determine the absolute magnitude of learning, it follows that equating performance at the start of training should lead to equivalent amounts of learning. Here we test this prediction by comparing learning on an abutting Vernier alignment task with stimuli presented at two retinal eccentricities (5 and 15 deg equated in terms of either retinal size (unscaled stimuli or cortical size (scaled stimuli. Prior to learning, unscaled stimuli produced larger alignment thresholds at the more peripheral eccentricity, whereas scaled stimuli produced equivalent alignment thresholds. Consistent with previous work, we found that the magnitude of learning for participants who trained over eight daily sessions with the unscaled stimuli (n=11 was significantly larger at 15 than 5 degrees eccentricity. However, when stimuli were spatially scaled (n=11, we found equivalent amounts of learning at each location. These data suggest differences in the magnitude of learning can be accounted for by differences in the cortical representation of stimuli. Cortical scale may set not only the initial performance level but also the upper limit for the magnitude of performance improvements following training.

  3. An Information-Processing Analysis of Children's Accuracy in Predicting the Appearance of Rotated Stimuli.

    Science.gov (United States)

    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…

  4. Het sex-in-the-crowd effect: Over het opvallen van seksuele stimuli

    NARCIS (Netherlands)

    A. Kennedy; H. Buis; M. Spiering

    2009-01-01

    Evolutionair gezien is het aannemelijk dat stimuli die de overleving en de reproductie bevorderen, sneller opvallen dan neutrale stimuli. Zo is aangetoond dat een bedreigend gezicht tussen neutrale gezichten eerder wordt gedecteerd dan andersom, het face-in-the-crowd effect (HAnsen & Hansen, 1988).

  5. EFFECTS OF THREE DIFFERENT STIMULI ON THE CREATIVITY OF CHILDREN'S COMPOSITIONS.

    Science.gov (United States)

    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…

  6. Effects of Background Color on Detecting Spot Stimuli in the Upper and Lower Visual Fields

    Science.gov (United States)

    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…

  7. Perseverative instrumental and Pavlovian responding to conditioned stimuli in serotonin transporter knockout rats

    NARCIS (Netherlands)

    Nonkes, L.J.P.; Homberg, J.R.

    2013-01-01

    Environmental stimuli can influence behavior via the process of Pavlovian conditioning. Recent genetic research suggests that some individuals are more sensitive to environmental stimuli for behavioral guidance than others. One important mediator of this effect is serotonin transporter (5-HTT) genet

  8. The vanilloid receptor family of calcium-permeable channels: molecular integrators of microenvironmental stimuli.

    Science.gov (United States)

    O'Neil, Roger G; Brown, Rachel C

    2003-12-01

    The TRPV subfamily of calcium-permeable channels is widely distributed in sensory and nonsensory cells from nematodes to mammals. These channels can be variably activated by a diverse range of stimuli (osmotic/mechanical stress, noxious chemicals and heat, endogenous mediators) that often converge on the same channel. Evidence is presented that TRPV channels function as novel "molecular integrators" of diverse microenvironmental stimuli.

  9. Conceptualizing Media Stimuli in Experimental Research: Psychological versus Attribute-Based Definitions

    Science.gov (United States)

    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…

  10. Vibratory Stimuli: A Novel Rehabilitation Method for Preventing Post-Traumatic Knee Osteoarthritis

    Science.gov (United States)

    2016-08-01

    meetings of the Osteoarthritis Research Society International, Athletic Trainers’ Osteoarthritis 6 Consortium, and National Athletic Trainers...AWARD NUMBER: W81XWH-15-1-0287 TITLE: Vibratory Stimuli, A Novel Rehabilitation Method for Preventing Post – Traumatic Knee Osteoarthritis ...August 2015 – 31 July 2016 4. TITLE AND SUBTITLE Vibratory Stimuli, A Novel Rehabilitation Method for Preventing Post – Traumatic Knee Osteoarthritis

  11. DHEA Enhances Emotion Regulation Neurocircuits and Modulates Memory for Emotional Stimuli

    Science.gov (United States)

    Sripada, Rebecca K; Marx, Christine E; King, Anthony P; Rajaram, Nirmala; Garfinkel, Sarah N; Abelson, James L; Liberzon, Israel

    2013-01-01

    Dehydroepiandrosterone (DHEA) is a neurosteroid with anxiolytic, antidepressant, and antiglucocorticoid properties. It is endogenously released in response to stress, and may reduce negative affect when administered exogenously. Although there have been multiple reports of DHEA's antidepressant and anxiolytic effects, no research to date has examined the neural pathways involved. In particular, brain imaging has not been used to link neurosteroid effects to emotion neurocircuitry. To investigate the brain basis of DHEA's impact on emotion modulation, patients were administered 400 mg of DHEA (N=14) or placebo (N=15) and underwent 3T fMRI while performing the shifted-attention emotion appraisal task (SEAT), a test of emotional processing and regulation. Compared with placebo, DHEA reduced activity in the amygdala and hippocampus, enhanced connectivity between the amygdala and hippocampus, and enhanced activity in the rACC. These activation changes were associated with reduced negative affect. DHEA reduced memory accuracy for emotional stimuli, and also reduced activity in regions associated with conjunctive memory encoding. These results demonstrate that DHEA reduces activity in regions associated with generation of negative emotion and enhances activity in regions linked to regulatory processes. Considering that activity in these regions is altered in mood and anxiety disorders, our results provide initial neuroimaging evidence that DHEA may be useful as a pharmacological intervention for these conditions and invite further investigation into the brain basis of neurosteroid emotion regulatory effects. PMID:23552182

  12. DHEA enhances emotion regulation neurocircuits and modulates memory for emotional stimuli.

    Science.gov (United States)

    Sripada, Rebecca K; Marx, Christine E; King, Anthony P; Rajaram, Nirmala; Garfinkel, Sarah N; Abelson, James L; Liberzon, Israel

    2013-08-01

    Dehydroepiandrosterone (DHEA) is a neurosteroid with anxiolytic, antidepressant, and antiglucocorticoid properties. It is endogenously released in response to stress, and may reduce negative affect when administered exogenously. Although there have been multiple reports of DHEA's antidepressant and anxiolytic effects, no research to date has examined the neural pathways involved. In particular, brain imaging has not been used to link neurosteroid effects to emotion neurocircuitry. To investigate the brain basis of DHEA's impact on emotion modulation, patients were administered 400 mg of DHEA (N=14) or placebo (N=15) and underwent 3T fMRI while performing the shifted-attention emotion appraisal task (SEAT), a test of emotional processing and regulation. Compared with placebo, DHEA reduced activity in the amygdala and hippocampus, enhanced connectivity between the amygdala and hippocampus, and enhanced activity in the rACC. These activation changes were associated with reduced negative affect. DHEA reduced memory accuracy for emotional stimuli, and also reduced activity in regions associated with conjunctive memory encoding. These results demonstrate that DHEA reduces activity in regions associated with generation of negative emotion and enhances activity in regions linked to regulatory processes. Considering that activity in these regions is altered in mood and anxiety disorders, our results provide initial neuroimaging evidence that DHEA may be useful as a pharmacological intervention for these conditions and invite further investigation into the brain basis of neurosteroid emotion regulatory effects.

  13. Sequences of abstract nonbiological stimuli share ventral premotor cortex with action observation and imagery.

    Science.gov (United States)

    Schubotz, Ricarda I; von Cramon, D Yves

    2004-06-16

    Activation triggered by either observed or imagined actions suggests that the ventral premotor cortex (PMv) provides an action vocabulary that allows us to detect and anticipate basically invariant perceptual states in observed actions. In the present study, we tested the hypothesis that the same PMv region is also recruited by nonbiological (abstract) stimulus sequences as long as the temporal order of stimuli has to be processed. Using functional magnetic resonance imaging, we instructed participants to assess expected outcomes in observed actions [external biological cues (EB)], motor imagery [internal biological cues (IB)], or geometrical figure sequences [external nonbiological cues (EN)]. As hypothesized, we found that each condition elicited significant activation within PMv [left hemisphere, Brodman Area (BA) 6], in contrast to a sequential target detection control task. In addition, cue-specific activations were identified in areas that were only engaged for biologically (action) cued (EB, IB) and nonbiologically cued (EN) tasks. Biologically cued tasks elicited activations within inferior frontal gyri adjacent to PMv (BA 44/45), in the frontomedian wall, the extrastriate body area, posterior superior temporal sulci, somatosensory cortices, and the amygdala-hippocampal-area, whereas the nonbiologically cued task engaged presupplementary motor area, middle frontal gyri, intraparietal sulci, and caudate nuclei of the basal ganglia. In sum, findings point to a basic premotor contribution to the representation or processing of sequentially structured events, supplemented by different sets of areas in the context of either biological or nonbiological cues.

  14. A flexible multi-stimuli in situ (S)TEM: Concept, optical performance, and outlook

    Energy Technology Data Exchange (ETDEWEB)

    Börrnert, Felix, E-mail: felix.boerrnert@triebenberg.de [Speziallabor Triebenberg, Technische Universität Dresden, 01062 Dresden (Germany); IFW Dresden, PF 27 01 16, 01171 Dresden (Germany); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Müller, Heiko; Riedel, Thomas; Linck, Martin [CEOS GmbH, Englerstraße 28, 69126 Heidelberg (Germany); Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Haider, Max. [CEOS GmbH, Englerstraße 28, 69126 Heidelberg (Germany); Büchner, Bernd [IFW Dresden, PF 27 01 16, 01171 Dresden (Germany); Lichte, Hannes [Speziallabor Triebenberg, Technische Universität Dresden, 01062 Dresden (Germany)

    2015-04-15

    The progress in (scanning) transmission electron microscopy development had led to an unprecedented knowledge of the microscopic structure of functional materials at the atomic level. Additionally, although not widely used yet, electron holography is capable to map the electric and magnetic potential distributions at the sub-nanometer scale. Nevertheless, in situ studies inside a (scanning) transmission electron microscope ((S)TEM) are extremely challenging because of the much restricted size and accessibility of the sample space. Here, we introduce a concept for a dedicated in situ (S)TEM with a large sample chamber for flexible multi-stimuli experimental setups and report about the electron optical performance of the instrument. We demonstrate a maximum resolving power of about 1 nm in conventional imaging mode and substantially better than 5 nm in scanning mode while providing an effectively usable “pole piece gap” of 70 mm. - Highlights: • A concept for a (S)TEM with a large sample chamber is outlined. • An actual microscope is modified and has now a 70 mm high sample space. • The resolving power is about 1 nm in TEM and better than 5 nm in STEM mode. • Possible dedicated in situ microscopes with present technology are discussed.

  15. Acute effects of LSD on amygdala activity during processing of fearful stimuli in healthy subjects

    Science.gov (United States)

    Mueller, F; Lenz, C; Dolder, P C; Harder, S; Schmid, Y; Lang, U E; Liechti, M E; Borgwardt, S

    2017-01-01

    Lysergic acid diethylamide (LSD) induces profound changes in various mental domains, including perception, self-awareness and emotions. We used functional magnetic resonance imaging (fMRI) to investigate the acute effects of LSD on the neural substrate of emotional processing in humans. Using a double-blind, randomised, cross-over study design, placebo or 100 μg LSD were orally administered to 20 healthy subjects before the fMRI scan, taking into account the subjective and pharmacological peak effects of LSD. The plasma levels of LSD were determined immediately before and after the scan. The study (including the a priori-defined study end point) was registered at ClinicalTrials.gov before study start (NCT02308969). The administration of LSD reduced reactivity of the left amygdala and the right medial prefrontal cortex relative to placebo during the presentation of fearful faces (PLSD-induced amygdala response to fearful stimuli and the LSD-induced subjective drug effects (PLSD modulates the engagement of brain regions that mediate emotional processing. PMID:28375205

  16. Altered sensitization patterns to sweet food stimuli in patients recovered from anorexia and bulimia nervosa.

    Science.gov (United States)

    Wagner, Angela; Simmons, Alan N; Oberndorfer, Tyson A; Frank, Guido K W; McCurdy-McKinnon, Danyale; Fudge, Julie L; Yang, Tony T; Paulus, Martin P; Kaye, Walter H

    2015-12-30

    Recent studies show that higher-order appetitive neural circuitry may contribute to restricted eating in anorexia nervosa (AN) and overeating in bulimia nervosa (BN). The purpose of this study was to determine whether sensitization effects might underlie pathologic eating behavior when a taste stimulus is administered repeatedly. Recovered AN (RAN, n=14) and BN (RBN, n=15) subjects were studied in order to avoid the confounding effects of altered nutritional state. Functional magnetic resonance imaging (fMRI) measured higher-order brain response to repeated tastes of sucrose (caloric) and sucralose (non-caloric). To test sensitization, the neuronal response to the first and second administration was compared. RAN patients demonstrated a decreased sensitization to sucrose in contrast to RBN patients who displayed the opposite pattern, increased sensitization to sucrose. However, the latter was not as pronounced as in healthy control women (n=13). While both eating disorder subgroups showed increased sensitization to sucralose, the healthy controls revealed decreased sensitization. These findings could reflect on a neuronal level the high caloric intake of RBN during binges and the low energy intake for RAN. RAN seem to distinguish between high energy and low energy sweet stimuli while RBN do not.

  17. Determination of hemispheric language dominance using functional MRI : comparison of visual and auditory stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ic Ryung; Ahn, Kook Jin; Lee, Jae Mun [The Catholic Univ. of Korea, Seoul (Korea, Republic of); Kim, Tae [The Catholic Magnetic Resonance Research Center, Seoul (Korea, Republic of)

    1999-12-01

    To assess the difference between auditory and visual stimuli when determining hemispheric language dominance by using functional MRI. In ten healthy adult volunteers (8 right-handed, 1 left-handed, 1 ambidextrous), motor language activation in axial slices of frontal lobe was mapped on a Simens 1.5T Vision Plus system using single-shot EPI. Series of 120 consecutive images per section were acquired during three cycles of task activation and rest. During each activation, a series of four syllables was delivered by means of both a visual and auditory method, and the volunteers were asked to mentally generate words starting with each syllable. In both in ferior frontal gyri and whole frontal lobes, lateralization indices were calculated from the activated pixels. We determined the language dominant hemisphere, and compared the results of the visual method and the auditory method. Seven right-handed persons were left-hemisphere dominant, and one left-handed and one ambidex-trous person were right-hemisphere dominant. Five of nine persons demonstrated larger lateralization indices with the auditory method than the visual method, while the remaining four showed larger lateralization indices with the visual method. No statistically significant difference was noted when comparing the results of the two methods(p>0.05). When determining hemispheric language dominance using functional MRI, the two methods are equally appropriate.

  18. Directional locomotion of C. elegans in the absence of external stimuli.

    Directory of Open Access Journals (Sweden)

    Margherita Peliti

    Full Text Available Many organisms respond to food deprivation by altering their pattern of movement, often in ways that appear to facilitate dispersal. While the behavior of the nematode C. elegans in the presence of attractants has been characterized, long-range movement in the absence of external stimuli has not been examined in this animal. Here we investigate the movement pattern of individual C. elegans over times of ∼1 hour after removal from food, using two custom imaging set-ups that allow us to track animals on large agar surfaces of 22 cm×22 cm. We find that a sizeable fraction of the observed trajectories display directed motion over tens of minutes. Remarkably, this directional persistence is achieved despite a local orientation memory that decays on the scale of about one minute. Furthermore, we find that such trajectories cannot be accounted for by simple random, isotropic models of animal locomotion. This directional behavior requires sensory neurons, but appears to be independent of known sensory signal-transduction pathways. Our results suggest that long-range directional behavior of C. elegans may not be driven by sensory cues.

  19. Effectiveness of three contingency-nonspecific stimuli on bathroom graffiti prevention in a college setting.

    Science.gov (United States)

    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.

  20. Testing the race model inequality in redundant stimuli with variable onset asynchrony

    DEFF Research Database (Denmark)

    Gondan, Matthias

    2009-01-01

    to the high number of statistical tests, Type I and II errors are increased. Here a straightforward method is demonstrated to collapse these multiple tests into one test by summing the inequalities for the different SOAs. The power of the procedure is substantially increased by assigning specific weights......In speeded response tasks with redundant signals, parallel processing of the signals is tested by the race model inequality. This inequality states that given a race of two signals, the cumulative distribution of response times for redundant stimuli never exceeds the sum of the cumulative...... distributions of response times for the single-modality stimuli. It has been derived for synchronous stimuli and for stimuli with stimulus onset asynchrony (SOA). In most experiments with asynchronous stimuli, discrete SOA values are chosen and the race model inequality is separately tested for each SOA. Due...

  1. Gender difference in event related potentials to masked emotional stimuli in the oddball task.

    Science.gov (United States)

    Kim, Eun Young; Lee, Seung-Hwan; Park, Gewnhi; Kim, Sangrae; Kim, Imyel; Chae, Jeong-Ho; Kim, Hyun Taek

    2013-06-01

    We investigated gender differences in event-related potential (ERP) responses to subliminally presented threat-related stimuli. Twenty-four participants were presented with threat-related and neutral pictures for a very brief period of time (17 ms). To explore gender differences in ERP responses to subliminally presented stimuli, we examined six ERP components [P1, N170, N250, P300, Early Posterior Negativity (EPN) and Late Positive Potential (LPP)]. The result revealed that only female participants showed significant increases in the N170 and the EPN in response to subliminally presented threat-related stimuli compared to neutral stimuli. Our results suggest that female participants exhibit greater cortical processing of subliminally presented threat-related stimuli than male participants.

  2. Magnitude judgments of loudness change for discrete, dynamic, and hybrid stimuli.

    Science.gov (United States)

    Pastore, Richard E; Flint, Jesse

    2011-04-01

    Recent investigations of loudness change within stimuli have identified differences as a function of direction of change and power range (e.g., Canévet, Acustica, 62, 2136-2142, 1986; Neuhoff, Nature, 395, 123-124, 1998), with claims of differences between dynamic and static stimuli. Experiment 1 provides the needed direct empirical evaluation of loudness change across static, dynamic, and hybrid stimuli. Consistent with recent findings for dynamic stimuli, quantitative and qualitative differences in pattern of loudness change were found as a function of power change direction. With identical patterns of loudness change, only quantitative differences were found across stimulus type. In Experiment 2, Points of Subjective loudness Equality (PSE) provided additional information about loudness judgments for the static and dynamic stimuli. Because the quantitative differences across stimulus type exceed the magnitude that could be expected based upon temporal integration by the auditory system, other factors need to be, and are, considered.

  3. Human thermal sensation: frequency response to sinusoidal stimuli at the surface of the skin

    DEFF Research Database (Denmark)

    Ring, J.W.; de Dear, Richard; Melikov, Arsen Krikor

    1993-01-01

    The question of how the human organism perceives changing thermal stimuli has been recently studied and reported in experiments where these stimuli were either ramps and plateaux or simply step changes. Other experiments have been done in which the stimuli have been periodically varying airflows...... function. This function is then compared with the functional form found in two experiments where the stimuli were pulsating airflows of differing frequency. The PSI model seems to simulate well the form of the response of the human skin system to varying temperature changes of a whole range of frequencies....... A psychosensory intensity (PSI) model has been developed to relate experimentally derived sensation data to simulated cutaneous thermoreceptor responses to the temperature ramp-plateaux and step stimuli applied to the skin surface by thermodes. From the point of view of signal processing, a natural extension...

  4. VR-MDS: multidimensional scaling for classification tasks of virtual and real stimuli.

    Science.gov (United States)

    Okamoto, S

    2014-04-01

    Evaluating the perceptual similarity between virtual and real sensory stimuli has been a serious problem for virtual reality interface researchers for a long time. One of the most commonly used evaluation methods is a classification task where assessors classify randomly presented stimuli into multiple candidate types. The results of this method are summarized using two types of confusion matrices, which have different stimulus sets. The present study developed a method that computes the locations of simulated and real stimuli in a perceptual space on the basis of the two confusion matrices. The spatial distribution of the stimuli allows us to visually interpret the perceptual relationships between stimuli and their perceptual dimensionality. This method is recommended when the guidance index based on the answer ratios of the confusion matrices is fairly high.

  5. Polymer-based stimuli-responsive recyclable catalytic systems for organic synthesis.

    Science.gov (United States)

    Zhang, Jingli; Zhang, Mingxi; Tang, Kangjian; Verpoort, Francis; Sun, Taolei

    2014-01-15

    The introduction of stimuli-responsive polymers into the study of organic catalysis leads to the generation of a new kind of polymer-based stimuli-responsive recyclable catalytic system. Owing to their reversible switching properties in response to external stimuli, these systems are capable of improving the mass transports of reactants/products in aqueous solution, modulating the chemical reaction rates, and switching the catalytic process on and off. Furthermore, their stimuli-responsive properties facilitate the separation and recovery of the active catalysts from the reaction mixtures. As a fascinating approach of the controllable catalysis, these stimuli-responsive catalytic systems including thermoresponsive, pH-responsive, chemo-mechano-chemical, ionic strength-responsive, and dual-responsive, are reviewed in terms of their nanoreactors and mechanisms.

  6. Stimuli-responsive biodegradable polymeric micelles for targeted cancer therapy

    NARCIS (Netherlands)

    Talelli, M.A.

    2011-01-01

    Thermosensitive and biodegradable polymeric micelles based on mPEG-b-pHPMAmLacn have shown very promising results during the past years. The results presented in this thesis illustrate the high potential of these micelles for anticancer therapy and imaging and fully justify further pharmaceutical

  7. Stimuli-sensitive nanoparticles for multiple anti-HIV microbicides

    Science.gov (United States)

    Giri, Namita; Oh, Byeongtaek; Lee, Chi H.

    2016-05-01

    This study is aimed to develop and evaluate an advanced intravaginal formulation for the delivery of multiple anti-HIV microbicides. Novel stimuli-sensitive nanoparticles (NPs) which protected the encapsulated drugs from being degraded in acidic pH conditions were made of Eudragit S-100® (ES100®), a pH-sensitive polymer. ES100® NPs were prepared using the quasi-emulsion solvent diffusion technique and loaded with two microbicides namely Tenofovir (TNF) and Etravirine (ETV). The effects of various fabrication parameters on the formulation properties were evaluated for the optimization of ES100® NPs. The morphology of the ES100® NPs was examined by scanning electron microscopy. The cytotoxicity of NPs containing microbicides individually or in a combination was assessed using cell viability and trans-epithelial electrical resistance (TEER) measurements. The cellular uptake rates of the model microbicides by human vaginal epithelial cells, VK2 E6/E7 cells, were evaluated using confocal microscopy and florescence-assisted cell sorting technique. ES100® NPs had a spherical shape, smooth surface, and uniform texture with a little aggregation. The average particle size for NPs loaded with TNF ranged from 125 to 230 nm, whereas those for ETV-loaded NPs ranged from 160 to 280 nm. ES100® NPs had zeta potential in the range of -5 to -10 mV. In-vitro release studies displayed the potential benefits of ES100® NPs in retaining and protecting the loaded microbicides at vaginal pH (acidic), but immediately releasing them as the pH changes to neutral or 7.4 (physiological pH). Cell viability studies demonstrated that ES100® NPs did not exert any cytotoxicity individually or in a combination of both microbicides. TEER measurements confirmed that ES100® NPs loaded with TNF and ETV did not cause any changes in the barrier integrity of VK2 E6/E7 cell monolayer. The cellular uptake study revealed that ES100® NPs were taken by vaginal epithelial cells through the endocytosis

  8. Migraine increases centre-surround suppression for drifting visual stimuli.

    Directory of Open Access Journals (Sweden)

    Josephine Battista

    Full Text Available BACKGROUND: The pathophysiology of migraine is incompletely understood, but evidence points to hyper-responsivity of cortical neurons being a key feature. The basis of hyper-responsiveness is not clear, with an excitability imbalance potentially arising from either reduced inhibition or increased excitation. In this study, we measure centre-surround contrast suppression in people with migraine as a perceptual analogue of the interplay between inhibition and excitation in cortical areas responsible for vision. We predicted that reduced inhibitory function in migraine would reduce perceptual surround suppression. Recent models of neuronal surround suppression incorporate excitatory feedback that drives surround inhibition. Consequently, an increase in excitation predicts an increase in perceptual surround suppression. METHODS AND FINDINGS: Twenty-six people with migraine and twenty approximately age- and gender-matched non-headache controls participated. The perceived contrast of a central sinusoidal grating patch (4 c/deg stationary grating, or 2 c/deg drifting at 2 deg/sec, 40% contrast was measured in the presence and absence of a 95% contrast annular grating (same orientation, spatial frequency, and drift rate. For the static grating, similar surround suppression strength was present in control and migraine groups with the presence of the surround resulting in the central patch appearing to be 72% and 65% of its true contrast for control and migraine groups respectively (t(44 = 0.81, p = 0.42. For the drifting stimulus, the migraine group showed significantly increased surround suppression (t(44 = 2.86, p<0.01, with perceived contrast being on average 53% of actual contrast for the migraine group and 68% for non-headache controls. CONCLUSIONS: In between migraines, when asymptomatic, visual surround suppression for drifting stimuli is greater in individuals with migraine than in controls. The data provides evidence for a

  9. The NIMH Child Emotional Faces Picture Set (NIMH-ChEFS): a new set of children's facial emotion stimuli.

    Science.gov (United States)

    Egger, Helen Link; Pine, Daniel S; Nelson, Eric; Leibenluft, Ellen; Ernst, Monique; Towbin, Kenneth E; Angold, Adrian

    2011-09-01

    With the emergence of new technologies, there has been an explosion of basic and clinical research on the affective and cognitive neuroscience of face processing and emotion perception. Adult emotional face stimuli are commonly used in these studies. For developmental research, there is a need for a validated set of child emotional faces. This paper describes the development of the National Institute of Mental Health Child Emotional Faces Picture Set (NIMH-ChEFS), a relatively large stimulus set with high quality, color images of the emotional faces of children. The set includes 482 photographs of fearful, angry, happy, sad and neutral child faces with two gaze conditions: direct and averted gaze. In this paper we describe the development of the NIMH-ChEFS and data on the set's validity based on ratings by 20 healthy adult raters. Agreement between the a priori emotion designation and the raters' labels was high and comparable with values reported for commonly used adult picture sets. Intensity, representativeness, and composite "goodness" ratings are also presented to guide researchers in their choice of specific stimuli for their studies. These data should give researchers confidence in the NIMH-ChEFS's validity for use in affective and social neuroscience research.

  10. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Directory of Open Access Journals (Sweden)

    Stefania Balzarotti

    Full Text Available The dorsolateral prefrontal cortex (DLPFC is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  11. Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory stimuli.

    Science.gov (United States)

    Wang, Rong; Wu, Lingjie; Tang, Zuohua; Sun, Xinghuai; Feng, Xiaoyuan; Tang, Weijun; Qian, Wen; Wang, Jie; Jin, Lixin; Zhong, Yufeng; Xiao, Zebin

    2017-04-15

    Cross-modal plasticity within the visual and auditory cortices of early binocularly blind macaques is not well studied. In this study, four healthy neonatal macaques were assigned to group A (control group) or group B (binocularly blind group). Sixteen months later, blood oxygenation level-dependent functional imaging (BOLD-fMRI) was conducted to examine the activation in the visual and auditory cortices of each macaque while being tested using pure tones as auditory stimuli. The changes in the BOLD response in the visual and auditory cortices of all macaques were compared with immunofluorescence staining findings. Compared with group A, greater BOLD activity was observed in the bilateral visual cortices of group B, and this effect was particularly obvious in the right visual cortex. In addition, more activated volumes were found in the bilateral auditory cortices of group B than of group A, especially in the right auditory cortex. These findings were consistent with the fact that there were more c-Fos-positive cells in the bilateral visual and auditory cortices of group B compared with group A (p visual cortices of binocularly blind macaques can be reorganized to process auditory stimuli after visual deprivation, and this effect is more obvious in the right than the left visual cortex. These results indicate the establishment of cross-modal plasticity within the visual and auditory cortices.

  12. Comparison of volume-selective z-shim and conventional EPI in fMRI studies using face stimuli

    CERN Document Server

    Fukunaga, Hu Cheng Srikanth Padmala Rena

    2013-01-01

    Single-shot gradient recalled echo planar imaging (EPI) is the primary tool for functional magnetic resonance imaging (fMRI). The image often suffers from signal drop near the air-tissue interface, such as the amygdala and regions of the orbitofrontal lobe. An effective way to correct for this type of artifact is by applying multi-shot EPI using different z-shimming. Unfortunately, the scanning efficiency is significantly lowered. More recently, a new technique called volume-selective z-shim was proposed to implement z-shim compensation to only specific slices with large susceptibility effects. The high imaging efficiency of volume selective z-shim makes it possible to substitute conventional EPI for whole brain studies. In this study two fMRI experiments were conducted to compare volume- selective z-shim and conventional EPI while subjects performed tasks on face stimuli. The comparison was focused on three brain regions: amygdala, hippocampus, and fusiform gyrus. Our results indicate that despite fewer volu...

  13. There are differences in cerebral activation between females in distinct menstrual phases during viewing of erotic stimuli: A fMRI study.

    Science.gov (United States)

    Gizewski, Elke R; Krause, Eva; Karama, Sherif; Baars, Anneke; Senf, Wolfgang; Forsting, Michael

    2006-09-01

    There is evidence that men experience more sexual arousal than women but also that women in mid-luteal phase experience more sexual arousal than women outside this phase. Recently, a few functional brain imaging studies have tackled the issue of gender differences as pertaining to reactions to erotica. The question of whether or not gender differences in reactions to erotica are maintained with women in different phases has not yet been answered from a functional brain imaging perspective. In order to examine this issue, functional MRI was performed in 22 male and 22 female volunteers. Subjects viewed erotic film excerpts alternating with emotionally neutral excerpts in a standard block-design paradigm. Arousal to erotic stimuli was evaluated using standard rating scales after scanning. Two-sample t-test with uncorrected P erotic stimuli and with corrected P erotic stimuli. Furthermore, gender differences with women in mid-luteal phases are similar to those in females outside the mid-luteal phase.

  14. In situ gelling stimuli-sensitive block copolymer hydrogels for drug delivery.

    Science.gov (United States)

    He, Chaoliang; Kim, Sung Wan; Lee, Doo Sung

    2008-05-08

    Stimuli-sensitive block copolymer hydrogels, which are reversible polymer networks formed by physical interactions and exhibit a sol-gel phase-transition in response to external stimuli, have great potential in biomedical and pharmaceutical applications, especially in site-specific controlled drug-delivery systems. The drug may be mixed with a polymer solution in vitro and the drug-loaded hydrogel can form in situ after the in vivo administration, such as injection; therefore, stimuli-sensitive block copolymer hydrogels have many advantages, such as simple drug formulation and administration procedures, no organic solvent, site-specificity, a sustained drug release behavior, less systemic toxicity and ability to deliver both hydrophilic and hydrophobic drugs. Among the stimuli in the biomedical applications, temperature and pH are the most popular physical and chemical stimuli, respectively. The temperature- and/or pH-sensitive block copolymer hydrogels for biomedical applications have been extensively developed in the past decade. This review focuses on recent development of the preparation and application for drug delivery of the block copolymer hydrogels that respond to temperature, pH or both stimuli, including poly(N-substituted acrylamide)-based block copolymers, poloxamers and their derivatives, poly(ethylene glycol)-polyester block copolymers, polyelectrolyte-based block copolymers and the polyelectrolyte-modified thermo-sensitive block copolymers. In addition, the hydrogels based on other stimuli-sensitive block copolymers are discussed.

  15. Multisensory aversive stimuli differentially modulate negative feelings in near and far space.

    Science.gov (United States)

    Taffou, Marine; Ondřej, Jan; O'Sullivan, Carol; Warusfel, Olivier; Dubal, Stéphanie; Viaud-Delmon, Isabelle

    2016-05-05

    Affect, space, and multisensory integration are processes that are closely linked. However, it is unclear whether the spatial location of emotional stimuli interacts with multisensory presentation to influence the emotional experience they induce in the perceiver. In this study, we used the unique advantages of virtual reality techniques to present potentially aversive crowd stimuli embedded in a natural context and to control their display in terms of sensory and spatial presentation. Individuals high in crowdphobic fear navigated in an auditory-visual virtual environment, in which they encountered virtual crowds presented through the visual channel, the auditory channel, or both. They reported the intensity of their negative emotional experience at a far distance and at a close distance from the crowd stimuli. Whereas auditory-visual presentation of close feared stimuli amplified negative feelings, auditory-visual presentation of distant feared stimuli did not amplify negative feelings. This suggests that spatial closeness allows multisensory processes to modulate the intensity of the emotional experience induced by aversive stimuli. Nevertheless, the specific role of auditory stimulation must be investigated to better understand this interaction between multisensory, affective, and spatial representation processes. This phenomenon may serve the implementation of defensive behaviors in response to aversive stimuli that are in position to threaten an individual's feeling of security.

  16. Determining the Optimal Number of Stimuli per Cranial Site during Transcranial Magnetic Stimulation Mapping

    Science.gov (United States)

    Schabrun, Siobhan M.

    2017-01-01

    The delivery of five stimuli to each cranial site is recommended during transcranial magnetic stimulation (TMS) mapping. However, this time-consuming practice restricts the use of TMS mapping beyond the research environment. While reducing the number of stimuli administered to each cranial site may improve efficiency and decrease physiological demand, doing so may also compromise the procedure's validity. Therefore, the aim of this study was to determine the minimum number of stimuli per cranial site required to obtain valid outcomes during TMS mapping. Map volume and centre of gravity (CoG) recordings obtained using five stimuli per cranial site were retrospectively compared to those obtained using one, two, three, and four stimuli per cranial site. For CoG longitude, one stimulus per cranial site produced valid recordings (ICC = 0.91, 95% CI 0.82 to 0.95). However, this outcome is rarely explored in isolation. As two stimuli per cranial site were required to obtain valid CoG latitude (ICC = 0.99, 95% CI 0.99 to 0.99) and map volume (ICC = 0.99, 95% CI 0.99 to 0.99) recordings, it is recommended that a minimum of two stimuli be delivered to each cranial site during TMS mapping in order to obtain valid outcomes. PMID:28331848

  17. Individual variation in habituation: behaviour over time toward different stimuli in threespine sticklebacks (Gasterosteus aculeatus)

    Science.gov (United States)

    Bell, Alison M.; Peeke, Harman V.S.

    2014-01-01

    Habituation, or the relatively permanent waning of a response as a result of repeated stimulation, is a form of behavioural plasticity that allows animals to filter out irrelevant stimuli and to focus selectively on important stimuli. Individuals that fail to habituate might be at a disadvantage if they continue to respond to irrelevant stimuli; therefore, habituation can have adaptive significance. In this study we compared rates of behaviour over time toward three different ecologically-relevant stimuli (food, a male intruder and a gravid female) in threespine sticklebacks (Gasterosteus aculeatus). We detected evidence for habituation to the stimuli, and males in this study were especially aggressive toward both male and female conspecifics. Although there were some clear temporal patterns that could be detected by looking at average behaviour, not all individuals behaved in the same ‘average’ way. We detected substantial inter-individual variation in behaviour toward all three stimuli, inter-individual variation in rates of habituation to both male and female conspecifics, but no evidence for correlations between behaviours across stimuli (behavioural syndromes). These results suggest that individual animals vary in rates of habituation, and prompt hypotheses about the causes and consequences of variation in rates of habituation. PMID:25678715

  18. Comparison of EEG propagation speeds under emotional stimuli on smartphone between the different anxiety states.

    Science.gov (United States)

    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.

  19. Attentional load modulates responses of human primary visual cortex to invisible stimuli.

    Science.gov (United States)

    Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

    2007-03-20

    Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

  20. Resistance to change and frequency of response-dependent stimuli uncorrelated with reinforcement.

    Science.gov (United States)

    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.

  1. Tactile perception: do distinct subpopulations explain differences in mislocalization rates of stimuli across fingertips?

    Science.gov (United States)

    Warren, Jay P; Tillery, Stephen I Helms

    2011-11-07

    In a previous study we were able to demonstrate that the Cutaneous Rabbit Effect (CRE) could be induced across fingertips using a form of the reduced rabbit paradigm and electrotactile stimuli. The CRE, as used here, is an illusory phenomenon where two stimuli are rapidly at a site and then a stimulus is presented to a nearby site. The perception of the second of the stimuli is not at its presented location but at a site between the first and last stimuli. In this experiment, though the overall population did perceive the mislocalized stimuli as the CRE would predict, some subjects were very infrequently observed to mislocalize stimuli due to the CRE or other effects. Here we further examine this phenomena, attempting to identify whether a subpopulation exists that rarely mislocalizes stimuli on their fingertips. To test for this subpopulation, we reexamined the collected data from the previously published experiment and other unpublished data relating to that study. By examining these data for rates of mislocalization utilizing our previous metric we identified that there is a perceptual subpopulation that very infrequently misidentifies the location of a fingertip stimulus.

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

    Directory of Open Access Journals (Sweden)

    Didoné, Dayane Domeneghini

    2016-02-01

    Full Text Available 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 /.

  3. Auditory stimuli mimicking ambient sounds drive temporal "delta-brushes" in premature infants.

    Directory of Open Access Journals (Sweden)

    Mathilde Chipaux

    Full Text Available In the premature infant, somatosensory and visual stimuli trigger an immature electroencephalographic (EEG pattern, "delta-brushes," in the corresponding sensory cortical areas. Whether auditory stimuli evoke delta-brushes in the premature auditory cortex has not been reported. Here, responses to auditory stimuli were studied in 46 premature infants without neurologic risk aged 31 to 38 postmenstrual weeks (PMW during routine EEG recording. Stimuli consisted of either low-volume technogenic "clicks" near the background noise level of the neonatal care unit, or a human voice at conversational sound level. Stimuli were administrated pseudo-randomly during quiet and active sleep. In another protocol, the cortical response to a composite stimulus ("click" and voice was manually triggered during EEG hypoactive periods of quiet sleep. Cortical responses were analyzed by event detection, power frequency analysis and stimulus locked averaging. Before 34 PMW, both voice and "click" stimuli evoked cortical responses with similar frequency-power topographic characteristics, namely a temporal negative slow-wave and rapid oscillations similar to spontaneous delta-brushes. Responses to composite stimuli also showed a maximal frequency-power increase in temporal areas before 35 PMW. From 34 PMW the topography of responses in quiet sleep was different for "click" and voice stimuli: responses to "clicks" became diffuse but responses to voice remained limited to temporal areas. After the age of 35 PMW auditory evoked delta-brushes progressively disappeared and were replaced by a low amplitude response in the same location. Our data show that auditory stimuli mimicking ambient sounds efficiently evoke delta-brushes in temporal areas in the premature infant before 35 PMW. Along with findings in other sensory modalities (visual and somatosensory, these findings suggest that sensory driven delta-brushes represent a ubiquitous feature of the human sensory cortex

  4. Bumblebees require visual pollen stimuli to initiate and multimodal stimuli to complete a full behavioral sequence in close-range flower orientation.

    Science.gov (United States)

    Wilmsen, Saskia; Gottlieb, Robin; Junker, Robert R; Lunau, Klaus

    2017-03-01

    Flower visits are complex encounters, in which animals are attracted by floral signals, guided toward the site of the first physical contact with a flower, land, and finally take up floral rewards. At close range, signals of stamens and pollen play an important role to facilitate flower handling in bees, yet the pollen stimuli eliciting behavioral responses are poorly known. In this study, we test the response of flower-naive bumblebees (Bombus terrestris) toward single and multimodal pollen stimuli as compared to natural dandelion pollen. As artificial pollen stimuli, we used the yellow flavonoid pigment quercetin, the scent compound eugenol, the amino acid proline, the monosaccharide glucose, and the texture of pollen-grain-sized glass pellets as a tactile stimulus. Three test stimuli, dandelion pollen, one out of various uni- and multimodal stimulus combinations, and a solvent control were presented simultaneously to individual bumblebees, whose response was recorded. The results indicate that bumblebees respond in an irreversible sequence of behavioral reactions. Bumblebees approached the visual stimulus quercetin as often as natural dandelion pollen. An additional olfactory stimulus resulted in slightly more frequent landings. The multimodal stimulus combinations including visual, olfactory, gustatory, and tactile stimuli elicited approaches, antennal contacts, and landings as often as natural pollen. Subsequent reactions like proboscis extension, mandible biting, and buzzing were more often but not regularly observed at dandelion pollen. Our study shows that visual signals of pollen are sufficient to trigger initial responses of bumblebees, whereas multimodal pollen stimuli elicit full behavioral response as compared to natural pollen. Our results suggest a major role of pollen cues for the attraction of bees toward flowers and also explain, why many floral guides mimic the visual signals of pollen and anthers, that is, the yellow and UV-absorbing color, to

  5. Image ambiguity and fluency.

    Science.gov (United States)

    Jakesch, Martina; Leder, Helmut; Forster, Michael

    2013-01-01

    Ambiguity is often associated with negative affective responses, and enjoying ambiguity seems restricted to only a few situations, such as experiencing art. Nevertheless, theories of judgment formation, especially the "processing fluency account", suggest that easy-to-process (non-ambiguous) stimuli are processed faster and are therefore preferred to (ambiguous) stimuli, which are hard to process. In a series of six experiments, we investigated these contrasting approaches by manipulating fluency (presentation duration: 10 ms, 50 ms, 100 ms, 500 ms, 1000 ms) and testing effects of ambiguity (ambiguous versus non-ambiguous pictures of paintings) on classification performance (Part A; speed and accuracy) and aesthetic appreciation (Part B; liking and interest). As indicated by signal detection analyses, classification accuracy increased with presentation duration (Exp. 1a), but we found no effects of ambiguity on classification speed (Exp. 1b). Fifty percent of the participants were able to successfully classify ambiguous content at a presentation duration of 100 ms, and at 500 ms even 75% performed above chance level. Ambiguous artworks were found more interesting (in conditions 50 ms to 1000 ms) and were preferred over non-ambiguous stimuli at 500 ms and 1000 ms (Exp. 2a - 2c, 3). Importantly, ambiguous images were nonetheless rated significantly harder to process as non-ambiguous images. These results suggest that ambiguity is an essential ingredient in art appreciation even though or maybe because it is harder to process.

  6. Image ambiguity and fluency.

    Directory of Open Access Journals (Sweden)

    Martina Jakesch

    Full Text Available Ambiguity is often associated with negative affective responses, and enjoying ambiguity seems restricted to only a few situations, such as experiencing art. Nevertheless, theories of judgment formation, especially the "processing fluency account", suggest that easy-to-process (non-ambiguous stimuli are processed faster and are therefore preferred to (ambiguous stimuli, which are hard to process. In a series of six experiments, we investigated these contrasting approaches by manipulating fluency (presentation duration: 10 ms, 50 ms, 100 ms, 500 ms, 1000 ms and testing effects of ambiguity (ambiguous versus non-ambiguous pictures of paintings on classification performance (Part A; speed and accuracy and aesthetic appreciation (Part B; liking and interest. As indicated by signal detection analyses, classification accuracy increased with presentation duration (Exp. 1a, but we found no effects of ambiguity on classification speed (Exp. 1b. Fifty percent of the participants were able to successfully classify ambiguous content at a presentation duration of 100 ms, and at 500 ms even 75% performed above chance level. Ambiguous artworks were found more interesting (in conditions 50 ms to 1000 ms and were preferred over non-ambiguous stimuli at 500 ms and 1000 ms (Exp. 2a - 2c, 3. Importantly, ambiguous images were nonetheless rated significantly harder to process as non-ambiguous images. These results suggest that ambiguity is an essential ingredient in art appreciation even though or maybe because it is harder to process.

  7. Development of Theory of Mind Stimuli in Magnetoencephalography for Nursing Evaluation

    Directory of Open Access Journals (Sweden)

    Sungwon Park

    2009-09-01

    Full Text Available We introduce the development of animation stimuli for theory of mind (ToM in magnetoencepalography (MEG. We will discuss apparatus for presenting animation stimuli and a technical problem like an eye movement signal generated from following triangles in the animations, and its rejection using independent component analysis (ICA. With the ToM animations and the apparatus, we conducted MEG measurements for 8 normal controls and 6 schizophrenic patients. We present a preliminary assessment result for the developed animation stimuli as a tool for ToM test, which has been obtained by scoring in the followingup interview after the MEG measurement.

  8. Polish pseudo-words list: dataset of 3023 stimuli with competent judges' ratings.

    Science.gov (United States)

    Imbir, Kamil K; Spustek, Tomasz; Żygierewicz, Jarosław

    2015-01-01

    Pseudo-words are stimuli, which are useful in research concerning lexical processing. As in the case of existing words, they are language dependent; thus, they should be generated for each language separately. The Polish Pseudo-words List (PPwL) is a dataset presenting a set of 3023 stimuli (words of 4-13 letters long). They were generated using an algorithm substituting random letters in existing words with respect to the frequency of letters in certain positions. We put out the raw set for a competent judges' assessment and included the responses in the dataset. PPwL allows the choice of suitable control stimuli for experiments concerning lexical processing.

  9. Aversive stimuli exacerbate defensive motor behaviour in motor conversion disorder.

    Science.gov (United States)

    Blakemore, Rebekah L; Sinanaj, Indrit; Galli, Silvio; Aybek, Selma; Vuilleumier, Patrik

    2016-12-01

    Conversion disorder or functional neurological symptom disorder (FND) can affect the voluntary motor system, without an organic cause. Functional symptoms are thought to be generated unconsciously, arising from underlying psychological stressors. However, attempts to demonstrate a direct relationship between the limbic system and disrupted motor function in FND are lacking. We tested whether negative affect would exacerbate alterations of motor control and corresponding brain activations in individuals with FND. Ten patients and ten healthy controls produced an isometric precision-grip contraction at 10% of maximum force while either viewing visual feedback of their force output, or unpleasant or pleasant emotional images (without feedback). Force magnitude was continuously recorded together with change in brain activity using fMRI. For controls, force output decayed from the target level while viewing pleasant and unpleasant images. Patients however, maintained force at the target level without decay while viewing unpleasant images, indicating a pronounced effect of negative affect on force output in FND. This emotional modulation of force control was associated with different brain activation patterns between groups. Contrasting the unpleasant with the pleasant condition, controls showed increased activity in the inferior frontal cortex and pre-supplementary motor area, whereas patients had greater activity in the cerebellum (vermis), posterior cingulate cortex, and hippocampus. Engagement of a cerebellar-limbic network in patients is consistent with heightened processing of emotional salience, and supports the role of the cerebellum in freezing responses in the presence of aversive events. These data highlight a possible neural circuit through which psychological stressors elicit defensive behaviour and modulate motor function in FND. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Spatial decisions and cognitive strategies of monkeys and humans based on abstract spatial stimuli in rotation test

    OpenAIRE

    Nekovarova, Tereza; Nedvidek, Jan; Klement, Daniel; Bures, Jan

    2009-01-01

    We showed previously that macaque monkeys (Macaca mulatta) could orient in real space using abstract visual stimuli presented on a computer screen. They made correct choices according to both spatial stimuli (designed as an abstract representation of a real space) and nonspatial stimuli (pictures lacking any inner configuration information). However, we suggested that there were differences in processing spatial and nonspatial stimuli. In the present experiment we show that monkeys could also...

  11. Effects of mindful-attention and compassion meditation training on amygdala response to emotional stimuli in an ordinary, non-meditative state

    Directory of Open Access Journals (Sweden)

    Gaelle eDesbordes

    2012-11-01

    Full Text Available The amygdala has been repeatedly implicated in emotional processing of both positive and negative valence stimuli. Previous studies suggest that the amygdala response to emotional stimuli is lower when the subject is in a meditative state of mindful attention, both in beginner meditators after an eight-week meditation intervention and in expert meditators. However, the longitudinal effects of meditation training on amygdala responses have not been reported when participants are in an ordinary, non-meditative state. In this study, we investigated how eight weeks of training in meditation affects amygdala responses to emotional stimuli in subjects when in a non-meditative state. Healthy adults with no prior meditation experience took part in eight weeks of either Mindful Attention Training, Cognitively-Based Compassion Training (CBCT; a program based on Tibetan Buddhist compassion meditation practices, or an active control intervention. Before and after the intervention, participants underwent an fMRI experiment during which they were presented images with positive, negative, and neutral emotional valences from the IAPS database while remaining in an ordinary, non-meditative state. Using a region-of-interest analysis, we found a longitudinal decrease in right amygdala activation in the Mindful Attention group in response to positive images, and in response to images of all valences overall. In the CBCT group, we found a trend increase in right amygdala response to negative images, which was significantly correlated with a decrease in depression score. No effects or trends were observed in the control group. This finding suggests that the effects of meditation training on emotional processing might transfer to non-meditative states. This is consistent with the hypothesis that meditation training may induce learning that is not stimulus- or task-specific, but process-specific, and thereby may result in enduring changes in mental function.

  12. Effects of mindful-attention and compassion meditation training on amygdala response to emotional stimuli in an ordinary, non-meditative state.

    Science.gov (United States)

    Desbordes, Gaëlle; Negi, Lobsang T; Pace, Thaddeus W W; Wallace, B Alan; Raison, Charles L; Schwartz, Eric L

    2012-01-01

    The amygdala has been repeatedly implicated in emotional processing of both positive and negative-valence stimuli. Previous studies suggest that the amygdala response to emotional stimuli is lower when the subject is in a meditative state of mindful-attention, both in beginner meditators after an 8-week meditation intervention and in expert meditators. However, the longitudinal effects of meditation training on amygdala responses have not been reported when participants are in an ordinary, non-meditative state. In this study, we investigated how 8 weeks of training in meditation affects amygdala responses to emotional stimuli in subjects when in a non-meditative state. Healthy adults with no prior meditation experience took part in 8 weeks of either Mindful Attention Training (MAT), Cognitively-Based Compassion Training (CBCT; a program based on Tibetan Buddhist compassion meditation practices), or an active control intervention. Before and after the intervention, participants underwent an fMRI experiment during which they were presented images with positive, negative, and neutral emotional valences from the IAPS database while remaining in an ordinary, non-meditative state. Using a region-of-interest analysis, we found a longitudinal decrease in right amygdala activation in the Mindful Attention group in response to positive images, and in response to images of all valences overall. In the CBCT group, we found a trend increase in right amygdala response to negative images, which was significantly correlated with a decrease in depression score. No effects or trends were observed in the control group. This finding suggests that the effects of meditation training on emotional processing might transfer to non-meditative states. This is consistent with the hypothesis that meditation training may induce learning that is not stimulus- or task-specific, but process-specific, and thereby may result in enduring changes in mental function.

  13. The effects of varied versus constant high-, medium-, and low-preference stimuli on performance

    National Research Council Canada - National Science Library

    Wine, Byron; Wilder, David A

    2009-01-01

    The purpose of the current study was to compare the delivery of varied versus constant high-, medium-, and low-preference stimuli on performance of 2 adults on a computer-based task in an analogue employment setting...

  14. A comparison of commercially available auditory brainstem response stimuli at a neurodiagnostic intensity level

    National Research Council Canada - National Science Library

    Keesling, Devan A; Parker, Jordan Paige; Sanchez, Jason Tait

    2017-01-01

    iChirp-evoked auditory brainstem responses (ABRs) yield a larger wave V amplitude at low intensity levels than traditional broadband click stimuli, providing a reliable estimation of hearing sensitivity...

  15. Stimuli-responsive Membranes: Smart Tools for Controllable Mass-transfer and Separation Processes

    Institute of Scientific and Technical Information of China (English)

    褚良银; 谢锐; 巨晓洁

    2011-01-01

    As emerging artificial biomimetic membranes, smart or intelligent membranes that are able to respond to environmental stimuli are attracting ever-increasing interests from various fields. Their permeation properties including hydraulic permeability and diffusional permeability can be dramatically controlled or adjusted self-regulatively in response to small chemical and/or physical stimuli in their environments. Such environmental stimuli-responsive smart membranes could find myriad applications in numerous fields ranging from controlled release to separations. Here the trans-membrane mass-transfer and membrane separation is introduced as the beginning to initiate the requirement of smart membranes, and then bio-inspired design of environmental stimuli-responsive smart membranes and four essential elements for smart membranes are introduced and discussed. Next, smart membrane types and their applications as smart tools for controllable mass-transfer in controlled release and separations are reviewed. The research tooics in the near future are also suggested.

  16. Activation of right parietal cortex during memory retrieval of nonlinguistic auditory stimuli.

    Science.gov (United States)

    Klostermann, Ellen C; Loui, Psyche; Shimamura, Arthur P

    2009-09-01

    In neuroimaging studies, the left ventral posterior parietal cortex (PPC) is particularly active during memory retrieval. However, most studies have used verbal or verbalizable stimuli. We investigated neural activations associated with the retrieval of short, agrammatical music stimuli (Blackwood, 2004), which have been largely associated with right hemisphere processing. At study, participants listened to music stimuli and rated them on pleasantness. At test, participants made old/new recognition judgments with high/low confidence ratings. Right, but not left, ventral PPC activity was observed during the retrieval of these music stimuli. Thus, rather than indicating a special status of left PPC in retrieval, both right and left ventral PPC participate in memory retrieval, depending on the type of information that is to be remembered.

  17. Categorization of extremely brief auditory stimuli: domain-specific or domain-general processes?

    Directory of Open Access Journals (Sweden)

    Emmanuel Bigand

    Full Text Available The present study investigated the minimum amount of auditory stimulation that allows differentiation of spoken voices, instrumental music, and environmental sounds. Three new findings were reported. 1 All stimuli were categorized above chance level with 50 ms-segments. 2 When a peak-level normalization was applied, music and voices started to be accurately categorized with 20 ms-segments. When the root-mean-square (RMS energy of the stimuli was equalized, voice stimuli were better recognized than music and environmental sounds. 3 Further psychoacoustical analyses suggest that the categorization of extremely brief auditory stimuli depends on the variability of their spectral envelope in the used set. These last two findings challenge the interpretation of the voice superiority effect reported in previously published studies and propose a more parsimonious interpretation in terms of an emerging property of auditory categorization processes.

  18. Activity Changes Induced by Spatio-Temporally Correlated Stimuli in Cultured Cortical Networks

    Science.gov (United States)

    Takayama, Yuzo; Moriguchi, Hiroyuki; Jimbo, Yasuhiko

    Activity-dependent plasticity probably plays a key role in learning and memory in biological information processing systems. Though long-term potentiation and depression have been extensively studied in the filed of neuroscience, little is known on the mechanisms for integrating these modifications on network-wide activity changes. In this report, we studied effects of spatio-temporally correlated stimuli on the neuronal network activity. Rat cortical neurons were cultured on substrates with 64 embedded micro-electrodes and the evoked responses were extracellularly recorded and analyzed. We compared spatio-temporal patterns of the responses between before and after repetitive application of correlated stimuli. After the correlated stimuli, the networks showed significantly different responses from those in the initial states. The modified activity reflected structures of the repeatedly applied correlated stimuli. The results suggested that spatiotemporally correlated inputs systematically induced modification of synaptic strengths in neuronal networks, which could serve as an underlying mechanism of associative memory.

  19. Influence of auditory and audiovisual stimuli on the right-left prevalence effect

    DEFF Research Database (Denmark)

    Vu, Kim-Phuong L; Minakata, Katsumi; Ngo, Mary Kim

    2014-01-01

    vertical coding through use of the spatial-musical association of response codes (SMARC) effect, where pitch is coded in terms of height in space. In Experiment 1, we found a larger right-left prevalence effect for unimodal auditory than visual stimuli. Neutral, non-pitch coded, audiovisual stimuli did...... not result in cross-modal facilitation, but did show evidence of visual dominance. The right-left prevalence effect was eliminated in the presence of SMARC audiovisual stimuli, but the effect influenced horizontal rather than vertical coding. Experiment 2 showed that the influence of the pitch dimension...... was not in terms of influencing response selection on a trial-to-trial basis, but in terms of altering the salience of the task environment. Taken together, these findings indicate that in the absence of salient vertical cues, auditory and audiovisual stimuli tend to be coded along the horizontal dimension...

  20. Involuntary Eye Movement during Fixation is Influenced by Spatio-Temporal Frequency of Visual Stimuli

    Directory of Open Access Journals (Sweden)

    Masae Yokota

    2011-05-01

    Full Text Available Involuntary eye movement during fixation is essential for visual information acquisition. Previous studies have suggested that such eye movement depends on the attributes of visual stimuli (e.g. Yokota, APCV2010. In this study, we focus on spatio-temporal frequency, as an attribute of visual stimuli in order to understand spatio-temporal frequency property in the pathway of human vision. We measured eye movement during fixation for three subjects when 16 random-dot dynamic textures that have various frequency bands in spatially and temporally, are presented to the subjects as visual stimuli. The result shows that eye movement depends on the spatio-temporal frequency of visual stimuli. The eye movement includes higher frequency components, in other words, higher velocity components, when visual stimulus has higher spatial frequency and/or higher temporal frequency. Future detailed experiments will show that involuntary eye movement during fixation might be influenced by spatio-temporal frequency sensitivity in vision.

  1. Affective states leak into movement execution: Automatic avoidance of threatening stimuli in fear of spider is visible in reach trajectories

    NARCIS (Netherlands)

    Buetti, S.; Juan, E.; Rinck, M.; Kerzel, D.

    2012-01-01

    Approach-like actions are initiated faster with stimuli of positive valence. Conversely, avoidance-like actions are initiated faster with threatening stimuli of negative valence. We went beyond reaction time measures and investigated whether threatening stimuli also affect the way in which an action

  2. The nature of the stimuli causing digestive juice secretion in Dionaea muscipula Ellis (venus's flytrap).

    Science.gov (United States)

    Robins, R J

    1976-01-01

    An investigation into the stimuli of the secretory system in the carnivorous plant Dionaea muscipula is presented. Secretion of fluid and protein are both stimulated by various nitrogenous small molecules. These secretions are studied as a function of time. A new method is described for the collection of secreted juice. Significant differences are found between the quantities of fluid and protein produced in response to different stimuli. The results are discussed in comparison to the mammalian gastro-intestinal secretory systems.

  3. ENTREPRENEUR'S ACTUAL BEHAVIORAL CONTROLS, PSYCHIC DISTANCE STIMULI, AND EXPORT MODE CHOICE

    OpenAIRE

    NGO VI DUNG; FRANK JANSSEN

    2015-01-01

    This paper looks at the mediating effect of entrepreneurs' actual behavioral controls on the relationship between psychic distance stimuli and export mode choice of SMEs. Based on a dataset of 84 Vietnamese exporters, we find that: (i) entrepreneurs' actual behavioral controls and organizational factors are determinants of Vietnamese SMEs' export mode choice; (ii) psychic distance (geographic distance and psychic distance stimuli) does not influence Vietnamese SMEs' export mode choice; (iii) ...

  4. The Analysis of Sensory Stimuli of Terror in A Rose for Emily

    Institute of Scientific and Technical Information of China (English)

    尚慧敏

    2015-01-01

    William Faulkner drew impressive pictures of terror in A Rose for Emily by visual descriptions, auditory descriptions, tactile descriptions, and olfactory descriptions. Through the biological analysis, people can figure out what kinds of stimuli in this work can produce terror, how the sensory organs respond to the terror stimuli and why readers fear them. It is proved that Faulkner’s description of terror is based on the system of men’s receiving information and the production mechanism of terror.

  5. Spontaneous attention to faces in Asperger Syndrome using ecologically valid static stimuli.

    OpenAIRE

    2013-01-01

    Previous eye tracking research on the allocation of attention to social information by individuals with autism spectrum disorders is equivocal and may be in part a consequence of variation in stimuli used between studies. The current study explored attention allocation to faces, and within faces, by individuals with Asperger syndrome using a range of static stimuli where faces were either viewed in isolation or viewed in the context of a social scene. Results showed that faces were viewed typ...

  6. Comparison of EEG propagation speeds under emotional stimuli on smartphone between the different anxiety states

    OpenAIRE

    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...

  7. Emotionally negative stimuli can overcome attentional deficits in patients with visuo-spatial hemineglect.

    Science.gov (United States)

    Grabowska, A; Marchewka, A; Seniów, J; Polanowska, K; Jednoróg, K; Królicki, L; Kossut, M; Członkowska, A

    2011-10-01

    Left unilateral spatial neglect resulting from right brain damage is characterized by loss of awareness for stimuli in the contralesional side of space, despite intact visual pathways. We examined using fMRI whether patients with neglect are more likely to consciously detect in the neglected hemifield, emotionally negative complex scenes rather than visually similar neutral pictures and if so, what neural mechanisms mediate this effect. Photographs of emotional and neutral scenes taken from the IAPS were presented in a divided visual field paradigm. As expected, the detection rate for emotional stimuli presented in the neglected field was higher than for neutral ones. Successful detection of emotional scenes as opposed to neutral stimuli in the left visual field (LVF) produced activations in the parahippocampal and anterior cingulate areas in the right hemisphere. Detection of emotional stimuli presented in the intact right visual field (RVF) activated a distributed network of structures in the left hemisphere, including anterior and posterior cingulate cortex, insula, as well as visual striate and extrastriate areas. LVF-RVF contrasts for emotional stimuli revealed activations in right and left attention related prefrontal areas whereas RVF-LVF comparison showed activations in the posterior cingulate and extrastriate visual cortex in the left hemisphere. An additional analysis contrasting detected vs. undetected emotional LVF stimuli showed involvement of left anterior cingulate, right frontal and extrastriate areas. We hypothesize that beneficial role of emotion in overcoming neglect is achieved by activation of frontal and limbic lobe networks, which provide a privileged access of emotional stimuli to attention by top-down modulation of processing in the higher-order extrastriate visual areas. Our results point to the importance of top-down regulatory role of the frontal attentional systems, which might enhance visual activations and lead to greater salience of

  8. Long-latency auditory evoked potentials with verbal and nonverbal stimuli.

    Science.gov (United States)

    Oppitz, Sheila Jacques; Didoné, Dayane Domeneghini; Silva, Débora Durigon da; Gois, Marjana; Folgearini, Jordana; Ferreira, Geise Corrêa; Garcia, Michele Vargas

    2015-01-01

    Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000Hz - frequent and 4000Hz - rare); and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare). Considering the component N2 for tone burst, the lowest latency found was 217.45ms for the BA/DI stimulus; the highest latency found was 256.5ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  9. The Effect of Age on Neural Processing of Pleasant Soft Touch Stimuli

    Directory of Open Access Journals (Sweden)

    April C May

    2014-02-01

    Full Text Available Tactile interactions with our environment stimulate afferent fibers within the skin, which deliver information about sensations of pain, texture, itch and other feelings to the brain as a comprehensive sense of self. These tactile interactions can stimulate brain regions involved in interoception and reward processing. This study examined subjective, behavioral, and neural processing as a function of age during stimulation of A-beta (Aβ and C tactile (CT afferents using a soft brush stroke task. 16 adolescents (ages 15-17, 22 young adults (ages 20-28, and 20 mature adults (ages 29-55 underwent a simple continuous performance task while periodically anticipating and experiencing a soft touch to the palm or forearm, during functional magnetic resonance imaging (fMRI. fMRI results showed that adolescents displayed greater bilateral posterior insula activation than young and mature adults across all conditions and stimulus types. Adolescents also demonstrated greater bilateral posterior insula activation than young and mature adults specifically in response to the soft touch condition. Adolescents also exhibited greater activation than mature adults in bilateral inferior frontal gyrus and striatum during the soft touch condition. However, mature adults showed greater striatum activation than adolescents and young adults during anticipation. In the left anterior cingulate cortex, mature adults exhibited greater activation than adolescents and young adults when anticipating the upcoming touch. These results support the hypothesis that adolescents show an exaggerated neural response to pleasant stimulation of afferents, which may have profound effects on how they approach or avoid social and risky situations. In particular, heightened interoceptive reactivity to pleasant stimuli might cause adolescents to seek experiences that are associated with pleasant stimulation.

  10. Local mechanical stimuli regulate bone formation and resorption in mice at the tissue level.

    Directory of Open Access Journals (Sweden)

    Friederike A Schulte

    Full Text Available Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident that changes in mechanical demands at the organ level must be interpreted at the tissue level where bone (remodeling takes place. Although assumed for a long time, the relationship between the locations of bone formation and resorption and the local mechanical environment is still under debate. The lack of suitable imaging modalities for measuring bone formation and resorption in vivo has made it difficult to assess the mechanoregulation of bone three-dimensionally by experiment. Using in vivo micro-computed tomography and high resolution finite element analysis in living mice, we show that bone formation most likely occurs at sites of high local mechanical strain (p<0.0001 and resorption at sites of low local mechanical strain (p<0.0001. Furthermore, the probability of bone resorption decreases exponentially with increasing mechanical stimulus (R(2 = 0.99 whereas the probability of bone formation follows an exponential growth function to a maximum value (R(2 = 0.99. Moreover, resorption is more strictly controlled than formation in loaded animals, and ovariectomy increases the amount of non-targeted resorption. Our experimental assessment of mechanoregulation at the tissue level does not show any evidence of a lazy zone and suggests that around 80% of all (remodeling can be linked to the mechanical micro-environment. These findings disclose how mechanical stimuli at the tissue level contribute to the regulation of bone adaptation at the organ level.

  11. Illusory Centrifugal Motion Direction Observed in Brief Stimuli: Psychophysics and Energy Model

    Directory of Open Access Journals (Sweden)

    Ruyuan Zhang

    2011-05-01

    Full Text Available All stationary stimuli of fixed duration have motion energy and the amount of motion energy increases with decreasing duration. Consequently, perception of motion direction could be biased if the readout mechanisms are unbalanced. Previous physiological study showed prefered direction of MT neurons in peripheral tend to be oriented away from fovea(Albright, 1989. Given the broadening of motion energy in brief stimuli, such effect should increase as the stimulus duration decreases. Here, we tested this hypothesis by presenting vertical gratings (0.5c/deg, raised cosine spatial envelope, radius = 5deg, 98% contrast with different speeds(2,4,8 16deg/sec and direction(moving towards fovea or moving away from fovea. And Stimuli were presented in a temporal Gaussian envelope with durations ranging between 5 and 500ms. Observers' task was to identify perceived motion direction (guessing when unsure. Results showed that as predicted, the observers were biased to perceive these stimuli as moving away from fovea. In summary, briefly presented stationary stimuli are perceived as moving in centrifugal direction when presented in visual periphery. One possible explanation for this illusion is that these stimuli, by virtue of their broad temporal frequency spectrum, stimulate centrifugally biased motion mechanisms in area MT.

  12. Eye movements in pedophiles: automatic and controlled attentional processes while viewing prepubescent stimuli.

    Science.gov (United States)

    Fromberger, Peter; Jordan, Kirsten; Steinkrauss, Henrike; von Herder, Jakob; Stolpmann, Georg; Kröner-Herwig, Birgit; Müller, Jürgen Leo

    2013-05-01

    Recent theories in sexuality highlight the importance of automatic and controlled attentional processes in viewing sexually relevant stimuli. The model of Spiering and Everaerd (2007) assumes that sexually relevant features of a stimulus are preattentively selected and automatically induce focal attention to these sexually relevant aspects. Whether this assumption proves true for pedophiles is unknown. It is aim of this study to test this assumption empirically for people suffering from pedophilic interests. Twenty-two pedophiles, 8 nonpedophilic forensic controls, and 52 healthy controls simultaneously viewed the picture of a child and the picture of an adult while eye movements were measured. Entry time was assessed as a measure of automatic attentional processes and relative fixation time in order to assess controlled attentional processes. Pedophiles demonstrated significantly shorter entry time to child stimuli than to adult stimuli. The opposite was the case for nonpedophiles, as they showed longer relative fixation time for adult stimuli, and, against all expectations, pedophiles also demonstrated longer relative fixation time for adult stimuli. The results confirmed the hypothesis that pedophiles automatically selected sexually relevant stimuli (children). Contrary to all expectations, this automatic selection did not trigger the focal attention to these sexually relevant pictures. Furthermore, pedophiles were first and longest attracted by faces and pubic regions of children; nonpedophiles were first and longest attracted by faces and breasts of adults. The results demonstrated, for the first time, that the face and pubic region are the most attracting regions in children for pedophiles.

  13. Auditory-visual aversive stimuli modulate the conscious experience of fear.

    Science.gov (United States)

    Taffou, Marine; Guerchouche, Rachid; Drettakis, George; Viaud-Delmon, Isabelle

    2013-01-01

    In a natural environment, affective information is perceived via multiple senses, mostly audition and vision. However, the impact of multisensory information on affect remains relatively undiscovered. In this study, we investigated whether the auditory-visual presentation of aversive stimuli influences the experience of fear. We used the advantages of virtual reality to manipulate multisensory presentation and to display potentially fearful dog stimuli embedded in a natural context. We manipulated the affective reactions evoked by the dog stimuli by recruiting two groups of participants: dog-fearful and non-fearful participants. The sensitivity to dog fear was assessed psychometrically by a questionnaire and also at behavioral and subjective levels using a Behavioral Avoidance Test (BAT). Participants navigated in virtual environments, in which they encountered virtual dog stimuli presented through the auditory channel, the visual channel or both. They were asked to report their fear using Subjective Units of Distress. We compared the fear for unimodal (visual or auditory) and bimodal (auditory-visual) dog stimuli. Dog-fearful participants as well as non-fearful participants reported more fear in response to bimodal audiovisual compared to unimodal presentation of dog stimuli. These results suggest that fear is more intense when the affective information is processed via multiple sensory pathways, which might be due to a cross-modal potentiation. Our findings have implications for the field of virtual reality-based therapy of phobias. Therapies could be refined and improved by implicating and manipulating the multisensory presentation of the feared situations.

  14. Classification of stimuli-responsive polymers as anticancer drug delivery systems.

    Science.gov (United States)

    Taghizadeh, Bita; Taranejoo, Shahrouz; Monemian, Seyed Ali; Salehi Moghaddam, Zoha; Daliri, Karim; Derakhshankhah, Hossein; Derakhshani, Zaynab

    2015-02-01

    Although several anticancer drugs have been introduced as chemotherapeutic agents, the effective treatment of cancer remains a challenge. Major limitations in the application of anticancer drugs include their nonspecificity, wide biodistribution, short half-life, low concentration in tumor tissue and systemic toxicity. Drug delivery to the tumor site has become feasible in recent years, and recent advances in the development of new drug delivery systems for controlled drug release in tumor tissues with reduced side effects show great promise. In this field, the use of biodegradable polymers as drug carriers has attracted the most attention. However, drug release is still difficult to control even when a polymeric drug carrier is used. The design of pharmaceutical polymers that respond to external stimuli (known as stimuli-responsive polymers) such as temperature, pH, electric or magnetic field, enzymes, ultrasound waves, etc. appears to be a successful approach. In these systems, drug release is triggered by different stimuli. The purpose of this review is to summarize different types of polymeric drug carriers and stimuli, in addition to the combination use of stimuli in order to achieve a better controlled drug release, and it discusses their potential strengths and applications. A survey of the recent literature on various stimuli-responsive drug delivery systems is also provided and perspectives on possible future developments in controlled drug release at tumor site have been discussed.

  15. Responses to conflicting stimuli in a simple stimulus-response pathway.

    Science.gov (United States)

    Baljon, Pieter Laurens; Wagenaar, Daniel A

    2015-02-11

    The "local bend response" of the medicinal leech (Hirudo verbana) is a stimulus-response pathway that enables the animal to bend away from a pressure stimulus applied anywhere along its body. The neuronal circuitry that supports this behavior has been well described, and its responses to individual stimuli are understood in quantitative detail. We probed the local bend system with pairs of electrical stimuli to sensory neurons that could not logically be interpreted as a single touch to the body wall and used multiple suction electrodes to record simultaneously the responses in large numbers of motor neurons. In all cases, responses lasted much longer than the stimuli that triggered them, implying the presence of some form of positive feedback loop to sustain the response. When stimuli were delivered simultaneously, the resulting motor neuron output could be described as an evenly weighted linear combination of the responses to the constituent stimuli. However, when stimuli were delivered sequentially, the second stimulus had greater impact on the motor neuron output, implying that the positive feedback in the system is not strong enough to render it immune to further input.

  16. Preserved Suppression of Salient Irrelevant Stimuli During Visual Search in Age-Associated Memory Impairment.

    Science.gov (United States)

    Lorenzo-López, Laura; Maseda, Ana; Buján, Ana; de Labra, Carmen; Amenedo, Elena; Millán-Calenti, José C

    2015-01-01

    Previous studies have suggested that older adults with age-associated memory impairment (AAMI) may show a significant decline in attentional resource capacity and inhibitory processes in addition to memory impairment. In the present paper, the potential attentional capture by task-irrelevant stimuli was examined in older adults with AAMI compared to healthy older adults using scalp-recorded event-related brain potentials (ERPs). ERPs were recorded during the execution of a visual search task, in which the participants had to detect the presence of a target stimulus that differed from distractors by orientation. To explore the automatic attentional capture phenomenon, an irrelevant distractor stimulus defined by a different feature (color) was also presented without previous knowledge of the participants. A consistent N2pc, an electrophysiological indicator of attentional deployment, was present for target stimuli but not for task-irrelevant color stimuli, suggesting that these irrelevant distractors did not attract attention in AAMI older adults. Furthermore, the N2pc for targets was significantly delayed in AAMI patients compared to healthy older controls. Together, these findings suggest a specific impairment of the attentional selection process of relevant target stimuli in these individuals and indicate that the mechanism of top-down suppression of entirely task-irrelevant stimuli is preserved, at least when the target and the irrelevant stimuli are perceptually very different.

  17. Preserved suppression of salient irrelevant stimuli during visual search in Age-Associated Memory Impairment

    Directory of Open Access Journals (Sweden)

    Laura eLorenzo-López

    2016-01-01

    Full Text Available Previous studies have suggested that older adults with age-associated memory impairment (AAMI may show a significant decline in attentional resource capacity and inhibitory processes in addition to memory impairment. In the present paper, the potential attentional capture by task-irrelevant stimuli was examined in older adults with AAMI compared to healthy older adults using scalp-recorded event-related brain potentials (ERPs. ERPs were recorded during the execution of a visual search task, in which the participants had to detect the presence of a target stimulus that differed from distractors by orientation. To explore the automatic attentional capture phenomenon, an irrelevant distractor stimulus defined by a different feature (color was also presented without previous knowledge of the participants. A consistent N2pc, an electrophysiological indicator of attentional deployment, was present for target stimuli but not for task-irrelevant color stimuli, suggesting that these irrelevant distractors did not attract attention in AAMI older adults. Furthermore, the N2pc for targets was significantly delayed in AAMI patients compared to healthy older controls. Together, these findings suggest a specific impairment of the attentional selection process of relevant target stimuli in these individuals and indicate that the mechanism of top-down suppression of entirely task-irrelevant stimuli is preserved, at least when the target and the irrelevant stimuli are perceptually very different.

  18. The Potential of Stimuli-Responsive Nanogels in Drug and Active Molecule Delivery for Targeted Therapy

    Directory of Open Access Journals (Sweden)

    Marta Vicario-de-la-Torre

    2017-05-01

    Full Text Available Nanogels (NGs are currently under extensive investigation due to their unique properties, such as small particle size, high encapsulation efficiency and protection of active agents from degradation, which make them ideal candidates as drug delivery systems (DDS. Stimuli-responsive NGs are cross-linked nanoparticles (NPs, composed of polymers, natural, synthetic, or a combination thereof that can swell by absorption (uptake of large amounts of solvent, but not dissolve due to the constituent structure of the polymeric network. NGs can undergo change from a polymeric solution (swell form to a hard particle (collapsed form in response to (i physical stimuli such as temperature, ionic strength, magnetic or electric fields; (ii chemical stimuli such as pH, ions, specific molecules or (iii biochemical stimuli such as enzymatic substrates or affinity ligands. The interest in NGs comes from their multi-stimuli nature involving reversible phase transitions in response to changes in the external media in a faster way than macroscopic gels or hydrogels due to their nanometric size. NGs have a porous structure able to encapsulate small molecules such as drugs and genes, then releasing them by changing their volume when external stimuli are applied.

  19. Matching- and nonmatching-to-sample concept learning in rats using olfactory stimuli.

    Science.gov (United States)

    April, L Brooke; Bruce, Katherine; Galizio, Mark

    2011-09-01

    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 matching or nonmatching training with 10 exemplars, the contingencies were reversed with five new stimuli such that subjects trained on matching were shifted to nonmatching and vice versa. Following these reversed contingencies, the effects of the original training persisted for many trials with new exemplars. In Experiment 2, 9 rats were trained with matching procedures in an arena that provided for 18 different spatial locations for comparison stimuli. Five subjects were trained with differential reinforcement outcomes and 4 with only one type of reinforcer. Differential outcomes and multiple exemplars facilitated learning, and there was strong evidence for generalization to new stimuli for most rats that acquired several conditional discriminations. Performances with novel samples were generally above chance, but rarely reached the high levels obtained during baseline with well-trained stimulus relations. However, taken together, the data from the two experiments extend previous work, show that rats can learn both match and nonmatch relations with different experimental protocols, and demonstrate generalization to novel sample stimuli.

  20. Skidmore Clips of Neutral and Expressive Scenarios (SCENES): Novel dynamic stimuli for social cognition research.

    Science.gov (United States)

    Schofield, Casey A; Weeks, Justin W; Taylor, Lea; Karnedy, Colten

    2015-12-30

    Social cognition research has relied primarily on photographic emotional stimuli. Such stimuli likely have limited ecological validity in terms of representing real world social interactions. The current study presents evidence for the validity of a new stimuli set of dynamic social SCENES (Skidmore Clips of Emotional and Neutral Expressive Scenarios). To develop these stimuli, ten undergraduate theater students were recruited to portray members of an audience. This audience was configured to display (seven) varying configurations of social feedback, ranging from unequivocally approving to unequivocally disapproving (including three different versions of balanced/neutral scenes). Validity data were obtained from 383 adult participants recruited from Amazon's Mechanical Turk. Each participant viewed three randomly assigned scenes and provided a rating of the perceived criticalness of each scene. Results indicate that the SCENES reflect the intended range of emotionality, and pairwise comparisons suggest that the SCENES capture distinct levels of critical feedback. Overall, the SCENES stimuli set represents a publicly available (www.scenesstimuli.com) resource for researchers interested in measuring social cognition in the presence of dynamic and naturalistic social stimuli. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  2. Fluid shifts across human dentine in vitro in response to hydrodynamic stimuli.

    Science.gov (United States)

    Pashley, D H; Matthews, W G; Zhang, Y; Johnson, M

    1996-11-01

    Most authorities agree that the hydrodynamic theory of dentine sensitivity best explains the stimulus-response relations of most painful stimuli. However, as the usual hydrodynamic stimuli are so different, it has been impossible to compare them. The equivalency of hydrodynamic stimuli can be evaluated from measurements of the fluid movement induced in vitro and relating this to the hydraulic conductance (Lp) of the same dentine specimen. From this determination, a common denominator is obtained which is equivalent to the hydrostatic pressure that would be required to cause the same magnitude of fluid movement. The purpose of this study was to measure the direction and magnitude of fluid shifts across dentine in extracted human crown segments with a flat, dentine occlusal surface in response to the following hydrodynamic stimuli; air blast, 56 degrees C water, 2 degrees C water, tactile and osmotic. In acid-etched superficial dentine, which simulates hypersensitive dentine, the largest to the smallest fluid flows obtained were: hot > cold > air blast > osmotic > tactile. When these were converted to equivalency units, the ranking of stimuli from strongest to weakest was hot > cold > air blast > osmotic > tactile. This new approach to comparing hydrodynamic stimuli should be verified in vivo.

  3. Effects of auditory stimuli in the horizontal plane on audiovisual integration: an event-related potential study.

    Science.gov (United States)

    Yang, Weiping; Li, Qi; Ochi, Tatsuya; Yang, Jingjing; Gao, Yulin; Tang, Xiaoyu; Takahashi, Satoshi; Wu, Jinglong

    2013-01-01

    This article aims to investigate whether auditory stimuli in the horizontal plane, particularly originating from behind the participant, affect audiovisual integration by using behavioral and event-related potential (ERP) measurements. In this study, visual stimuli were presented directly in front of the participants, auditory stimuli were presented at one location in an equidistant horizontal plane at the front (0°, the fixation point), right (90°), back (180°), or left (270°) of the participants, and audiovisual stimuli that include both visual stimuli and auditory stimuli originating from one of the four locations were simultaneously presented. These stimuli were presented randomly with equal probability; during this time, participants were asked to attend to the visual stimulus and respond promptly only to visual target stimuli (a unimodal visual target stimulus and the visual target of the audiovisual stimulus). A significant facilitation of reaction times and hit rates was obtained following audiovisual stimulation, irrespective of whether the auditory stimuli were presented in the front or back of the participant. However, no significant interactions were found between visual stimuli and auditory stimuli from the right or left. Two main ERP components related to audiovisual integration were found: first, auditory stimuli from the front location produced an ERP reaction over the right temporal area and right occipital area at approximately 160-200 milliseconds; second, auditory stimuli from the back produced a reaction over the parietal and occipital areas at approximately 360-400 milliseconds. Our results confirmed that audiovisual integration was also elicited, even though auditory stimuli were presented behind the participant, but no integration occurred when auditory stimuli were presented in the right or left spaces, suggesting that the human brain might be particularly sensitive to information received from behind than both sides.

  4. Dual stimuli polysaccharide nanovesicles for conjugated and physically loaded doxorubicin delivery in breast cancer cells

    Science.gov (United States)

    Pramod, P. S.; Shah, Ruchira; Jayakannan, Manickam

    2015-04-01

    The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the administration of doxorubicin via physical loading and polymer-drug conjugation to breast cancer cells. Dextran was suitably modified with a renewable resource 3-pentadecyl phenol unit through imine and aliphatic ester chemical linkages that acted as pH and esterase enzyme stimuli, respectively. These dual responsive polysaccharide derivatives self-organized into 200 +/- 10 nm diameter nano-vesicles in water. The water soluble anticancer drug doxorubicin (DOX.HCl) was encapsulated in the hydrophilic pocket to produce core-loaded polysaccharide vesicles whereas chemical conjugation produced DOX anchored at the hydrophobic layer of the dextran nano-vesicles. In vitro studies revealed that about 70-80% of the drug was retained under circulatory conditions at pH = 7.4 and 37 °C. At a low pH of 6.0 to 5.0 and in the presence of esterase; both imine and ester linkages were cleaved instantaneously to release 100% of the loaded drugs. Cytotoxicity assays on Wild Type Mouse Embryonic Fibroblasts (WTMEFs) confirmed the non-toxicity of the newly developed dextran derivatives at up to 500 μg mL-1 in PBS. MTT assays on fibroblast cells revealed that DOX.HCl loaded nano-vesicles exhibited better killing abilities than DOX conjugated polymer nano-vesicles. Both DOX loaded and DOX conjugated nano-vesicles were found to show significant killing in breast cancer cells (MCF 7). Confocal microscopy images confirmed the uptake of DOX loaded (or conjugated) nano-vesicles by cells compared to free DOX. Thus, the newly developed pH and enzyme dual responsive polysaccharide vesicular assemblies are potential drug vectors for the administration of DOX in both loaded and chemically conjugated forms for the efficient killing of breast cancer cells.The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the

  5. "A cigarette a day keeps the goodies away": smokers show automatic approach tendencies for smoking--but not for food-related stimuli.

    Directory of Open Access Journals (Sweden)

    Alla Machulska

    Full Text Available Smoking leads to the development of automatic tendencies that promote approach behavior toward smoking-related stimuli which in turn may maintain addictive behavior. The present study examined whether automatic approach tendencies toward smoking-related stimuli can be measured by using an adapted version of the Approach-Avoidance Task (AAT. Given that progression of addictive behavior has been associated with a decreased reactivity of the brain reward system for stimuli signaling natural rewards, we also used the AAT to measure approach behavior toward natural rewarding stimuli in smokers. During the AAT, 92 smokers and 51 non-smokers viewed smoking-related vs. non-smoking-related pictures and pictures of natural rewards (i.e. highly palatable food vs. neutral pictures. They were instructed to ignore image content and to respond to picture orientation by either pulling or pushing a joystick. Within-group comparisons revealed that smokers showed an automatic approach bias exclusively for smoking-related pictures. Contrary to our expectations, there was no difference in smokers' and non-smokers' approach bias for nicotine-related stimuli, indicating that non-smokers also showed approach tendencies for this picture category. Yet, in contrast to non-smokers, smokers did not show an approach bias for food-related pictures. Moreover, self-reported smoking attitude could not predict approach-avoidance behavior toward nicotine-related pictures in smokers or non-smokers. Our findings indicate that the AAT is suited for measuring smoking-related approach tendencies in smokers. Furthermore, we provide evidence for a diminished approach tendency toward food-related stimuli in smokers, suggesting a decreased sensitivity to natural rewards in the course of nicotine addiction. Our results indicate that in contrast to similar studies conducted in alcohol, cannabis and heroin users, the AAT might only be partially suited for measuring smoking-related approach

  6. The presence of a culturally similar or dissimilar social partner affects neural responses to emotional stimuli

    Directory of Open Access Journals (Sweden)

    Kate A. Woodcock

    2013-06-01

    Full Text Available Background: Emotional responding is sensitive to social context; however, little emphasis has been placed on the mechanisms by which social context effects changes in emotional responding. Objective: We aimed to investigate the effects of social context on neural responses to emotional stimuli to inform on the mechanisms underpinning context-linked changes in emotional responding. Design: We measured event-related potential (ERP components known to index specific emotion processes and self-reports of explicit emotion regulation strategies and emotional arousal. Female Chinese university students observed positive, negative, and neutral photographs, whilst alone or accompanied by a culturally similar (Chinese or dissimilar researcher (British. Results: There was a reduction in the positive versus neutral differential N1 amplitude (indexing attentional capture by positive stimuli in the dissimilar relative to alone context. In this context, there was also a corresponding increase in amplitude of a frontal late positive potential (LPP component (indexing engagement of cognitive control resources. In the similar relative to alone context, these effects on differential N1 and frontal LPP amplitudes were less pronounced, but there was an additional decrease in the amplitude of a parietal LPP component (indexing motivational relevance in response to positive stimuli. In response to negative stimuli, the differential N1 component was increased in the similar relative to dissimilar and alone (trend context. Conclusion: These data suggest that neural processes engaged in response to emotional stimuli are modulated by social context. Possible mechanisms for the social-context-linked changes in attentional capture by emotional stimuli include a context-directed modulation of the focus of attention, or an altered interpretation of the emotional stimuli based on additional information proportioned by the context.

  7. EEG Oscillation Evidences of Enhanced Susceptibility to Emotional Stimuli during Adolescence

    Science.gov (United States)

    Meng, Xianxin; Liu, Wenwen; Zhang, Ling; Li, Xiang; Yao, Bo; Ding, Xinsheng; Yuan, JiaJin; Yang, Jiemin

    2016-01-01

    Background: Our recent event-related potential (ERP) study showed that adolescents are more emotionally sensitive to negative events compared to adults, regardless of the valence strength of the events. The current work aimed to confirm this age-related difference in response to emotional stimuli of diverse intensities by examining Electroencephalography (EEG) oscillatory power in time-frequency analysis. Methods: Time-frequency analyses were performed on the EEG data recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults during a covert emotional task. The results showed a significant age by emotion interaction effect in the theta and beta oscillatory power during the 500–600 ms post stimulus. Results: Adolescents showed significantly less pronounced theta synchronization (ERS, 5.5–7.5 Hz) for HN stimuli, and larger beta desynchronization (ERD; 18–20 Hz) for both HN and MN stimuli, in comparison with neutral stimuli. By contrast, adults exhibited no significant emotion effects in theta and beta frequency bands. In addition, the analysis of the alpha spectral power (10.5–12 Hz; 850–950 ms) showed a main effect of emotion, while the emotion by age interaction was not significant. Irrespective of adolescents or adults, HN and MN stimuli elicited enhanced alpha suppression compared to Neutral stimuli, while the alpha power was similar across HN and MN conditions. Conclusions: These results confirmed prior findings that adolescents are more sensitive to emotionally negative stimuli compared to adults, regardless of emotion intensity, possibly due to the developing prefrontal control system during adolescence. PMID:27242568

  8. Investigating the Predictive Value of Functional MRI to Appetitive and Aversive Stimuli: A Pattern Classification Approach

    Science.gov (United States)

    McCabe, Ciara; Rocha-Rego, Vanessa

    2016-01-01

    Background Dysfunctional neural responses to appetitive and aversive stimuli have been investigated as possible biomarkers for psychiatric disorders. However it is not clear to what degree these are separate processes across the brain or in fact overlapping systems. To help clarify this issue we used Gaussian process classifier (GPC) analysis to examine appetitive and aversive processing in the brain. Method 25 healthy controls underwent functional MRI whilst seeing pictures and receiving tastes of pleasant and unpleasant food. We applied GPCs to discriminate between the appetitive and aversive sights and tastes using functional activity patterns. Results The diagnostic accuracy of the GPC for the accuracy to discriminate appetitive taste from neutral condition was 86.5% (specificity = 81%, sensitivity = 92%, p = 0.001). If a participant experienced neutral taste stimuli the probability of correct classification was 92. The accuracy to discriminate aversive from neutral taste stimuli was 82.5% (specificity = 73%, sensitivity = 92%, p = 0.001) and appetitive from aversive taste stimuli was 73% (specificity = 77%, sensitivity = 69%, p = 0.001). In the sight modality, the accuracy to discriminate appetitive from neutral condition was 88.5% (specificity = 85%, sensitivity = 92%, p = 0.001), to discriminate aversive from neutral sight stimuli was 92% (specificity = 92%, sensitivity = 92%, p = 0.001), and to discriminate aversive from appetitive sight stimuli was 63.5% (specificity = 73%, sensitivity = 54%, p = 0.009). Conclusions Our results demonstrate the predictive value of neurofunctional data in discriminating emotional and neutral networks of activity in the healthy human brain. It would be of interest to use pattern recognition techniques and fMRI to examine network dysfunction in the processing of appetitive, aversive and neutral stimuli in psychiatric disorders. Especially where problems with reward and punishment processing have been implicated in the

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

    Science.gov (United States)

    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.

  10. Design, syntheses, and properties of tunable, dual-stimuli (temperature and pH) responsive copolymers

    Science.gov (United States)

    Manokruang, Kiattikhun

    Stimuli responsive polymers are of great interest in biorelated applications ranging from actuators, microfluidics, delivery systems and tissue scaffolds. The specifications of an appropriate polymer system that shows a response to one or more external stimuli vary from application to application, depending on desired functionality. In most cases, the response to an environmental change is desired to be sharp and fast, such as for microfluidics and actuators, while the stability of the collapsed structure is also typically required, such as in tissue scaffolds and in stimulated delivery systems. In addition, the onset of the stimulus response varies depending on application. Thus, a general design strategy for polymer systems to meet specific applications' needs can be a big challenge. This dissertation describes the design, syntheses, and aqueous phase behavior of two polymer classes that show a sharp solution phase transition in different manners: The first polymer class is in the form of a segmented/blocky copolymer and its solution phase separation is designed to occur via micellization, while the second polymer class is designed as an alternating copolymer and it exhibits a first order LCST phase behavior. Copolymers of methyl methacrylate (MMA) and methacrylic acid (MAA), poly(MMA-co-MAA)s, were prepared to have a segmented blocky comonomer distribution along the chain backbone, with sequences composed predominantly of MMA or MAA units. Turbidity (cloud point) measurements were employed to investigate the phase behavior of these copolymers in aqueous solution. The solutions showed sharp solubility transitions upon pH change, and the pH-onsets of the copolymers' transition showed a systematic dependence on the copolymers' MAA content and an almost-linear dependence on the polymer concentration. A strong hysteresis was observed when lowering versus increasing pH, indicating a stable collapsed structure. Dynamic light scattering demonstrated almost monodispersed

  11. Mental transformations of spatial stimuli in humans and in monkeys: rotation vs. translocation.

    Science.gov (United States)

    Nekovarova, Tereza; Nedvidek, Jan; Klement, Daniel; Rokyta, Richard; Bures, Jan

    2013-03-01

    We studied the ability of monkeys and humans to orient in one spatial frame ("response frame") according to abstract spatial stimuli presented in another spatial frame ("stimulus frame"). The stimuli were designed as simple maps of the "response space". We studied how the transformations of these stimuli affected the performance. The subjects were trained to choose a particular position in the response frame - either on a touch screen (monkeys) or on a keyboard (humans) - according to schematic spatial stimuli presented on the stimulus screen. The monkeys responded by touching one of four circles shown in corners of a rectangle displayed on the touch screen. The correct position was signaled by the stimulus ("map") presented on the stimulus screen. The map was a complementary rectangle, but only with one circle shown ("pointer"). The position of this circle indicated the correct position in the response frame. In the first experiment we only manipulated stimuli presented on the computer screen. The "map" was originally shown in the same position and orientation as the "response pattern" but later the position and the rotation of the map on the screen were changing. Such transformations of the stimuli allow us to study the mental operations that the animals performed and how particular mental transformations mutually differed. In the second experiment we tested whether the monkeys relied more on stimuli presented on the screen or on the surrounding stable environment and objects. We compared the performance of animals in tasks with rotated virtual maps in a stable surrounding environment with the performance in tasks where we rotated the surrounding frame (computer monitor), whereas the stimuli on the screen remained stable. In the third experiment we tested human subjects in analogous tests to compare the ability and cognitive strategies of monkeys and humans in this task. We showed that the mental strategies that monkeys used for orientation in one spatial frame

  12. Encoding of naturalistic stimuli by local field potential spectra in networks of excitatory and inhibitory neurons.

    Directory of Open Access Journals (Sweden)

    Alberto Mazzoni

    2008-12-01

    Full Text Available Recordings of local field potentials (LFPs reveal that the sensory cortex displays rhythmic activity and fluctuations over a wide range of frequencies and amplitudes. Yet, the role of this kind of activity in encoding sensory information remains largely unknown. To understand the rules of translation between the structure of sensory stimuli and the fluctuations of cortical responses, we simulated a sparsely connected network of excitatory and inhibitory neurons modeling a local cortical population, and we determined how the LFPs generated by the network encode information about input stimuli. We first considered simple static and periodic stimuli and then naturalistic input stimuli based on electrophysiological recordings from the thalamus of anesthetized monkeys watching natural movie scenes. We found that the simulated network produced stimulus-related LFP changes that were in striking agreement with the LFPs obtained from the primary visual cortex. Moreover, our results demonstrate that the network encoded static input spike rates into gamma-range oscillations generated by inhibitory-excitatory neural interactions and encoded slow dynamic features of the input into slow LFP fluctuations mediated by stimulus-neural interactions. The model cortical network processed dynamic stimuli with naturalistic temporal structure by using low and high response frequencies as independent communication channels, again in agreement with recent reports from visual cortex responses to naturalistic movies. One potential function of this frequency decomposition into independent information channels operated by the cortical network may be that of enhancing the capacity of the cortical column to encode our complex sensory environment.

  13. Depersonalization disorder: disconnection of cognitive evaluation from autonomic responses to emotional stimuli.

    Directory of Open Access Journals (Sweden)

    Matthias Michal

    Full Text Available 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.

  14. Auditory stimulus timing influences perceived duration of co-occurring visual stimuli

    Directory of Open Access Journals (Sweden)

    Vincenzo eRomei

    2011-09-01

    Full Text Available There is increasing interest in multisensory influences upon sensory-specific judgements, such as when auditory stimuli affect visual perception. Here we studied whether the duration of an auditory event can objectively affect the perceived duration of a co-occurring visual event. On each trial, participants were presented with a pair of successive flashes and had to judge whether the first or second was longer. Two beeps were presented with the flashes. The order of short and long stimuli could be the same across audition and vision (audiovisual congruent or reversed, so that the longer flash was accompanied by the shorter beep and vice versa (audiovisual incongruent; or the two beeps could have the same duration as each other. Beeps and flashes could onset synchronously or asynchronously. In a further control experiment, the beep durations were much longer (tripled than the flashes. Results showed that visual duration-discrimination sensitivity (d' was significantly higher for congruent (and significantly lower for incongruent audiovisual synchronous combinations, relative to the visual only presentation. This effect was abolished when auditory and visual stimuli were presented asynchronously, or when sound durations tripled those of flashes. We conclude that the temporal properties of co-occurring auditory stimuli influence the perceived duration of visual stimuli and that this can reflect genuine changes in visual sensitivity rather than mere response bias.

  15. Background music genre can modulate flavor pleasantness and overall impression of food stimuli.

    Science.gov (United States)

    Fiegel, Alexandra; Meullenet, Jean-François; Harrington, Robert J; Humble, Rachel; Seo, Han-Seok

    2014-05-01

    This study aimed to determine whether background music genre can alter food perception and acceptance, but also to determine how the effect of background music can vary as a function of type of food (emotional versus non-emotional foods) and source of music performer (single versus multiple performers). The music piece was edited into four genres: classical, jazz, hip-hop, and rock, by either a single or multiple performers. Following consumption of emotional (milk chocolate) or non-emotional food (bell peppers) with the four musical stimuli, participants were asked to rate sensory perception and impression of food stimuli. Participants liked food stimuli significantly more while listening to the jazz stimulus than the hip-hop stimulus. Further, the influence of background music on overall impression was present in the emotional food, but not in the non-emotional food. In addition, flavor pleasantness and overall impression of food stimuli differed between music genres arranged by a single performer, but not between those by multiple performers. In conclusion, our findings demonstrate that music genre can alter flavor pleasantness and overall impression of food stimuli. Furthermore, the influence of music genre on food acceptance varies as a function of the type of served food and the source of music performer.

  16. Narcissism dimensions differentially moderate selective attention to evaluative stimuli in incarcerated offenders.

    Science.gov (United States)

    Krusemark, Elizabeth A; Lee, Christopher; Newman, Joseph P

    2015-01-01

    Narcissistic personality disorder is associated with distinguishing traits including self-enhancement, arrogance, and intense reactivity to ego threat. Theoretical accounts of narcissism suggest these heterogeneous behaviors reflect a defensive motivational style that functions to both uphold and protect the self-concept. However, the notion that narcissism can be characterized by grandiose and vulnerable dimensions raises the possibility that these diverse behaviors represent distinct expressions of narcissistic defensiveness. The present study examined whether both dimensions exhibit a general defensive style marked by selective attention to evaluative stimuli or are differentially associated with selective attention to positive and negative information, respectively. Using a dot probe task consisting of valenced and neutral trait adjectives, we evaluated these hypotheses in a group of male offenders. Results indicated that vulnerable narcissism was associated with attention biases for both positive and negative stimuli, though the dimension was further distinguished by disengagement difficulties and a greater recognition memory bias in response to negative words. Conversely, grandiose narcissism was associated with increased accuracy when attending to positive stimuli and directing attention away from negative stimuli. Overall, these findings suggest narcissistic individuals share motivated selective attention in response to evaluative stimuli, while simultaneously highlighting important phenotypic differences between grandiose and vulnerable dimensions.

  17. SYMMETRY IN THE PIGEON WITH SAMPLE AND COMPARISON STIMULI IN DIFFERENT LOCATIONS

    Science.gov (United States)

    Swisher, Melissa; Urcuioli, Peter J.

    2017-01-01

    Pigeons typically do not show evidence for symmetry in two-alternative matching-to-sample but do demonstrate this emergent relation in successive (go/no-go) matching-to-sample. Because the sample and comparison stimuli are presented in the same spatial location (viz., on one key) during successive matching training and testing, this may be one reason why pigeons pass tests for symmetry in this paradigm. To evaluate this, one group of pigeons received successive matching training with hue-sample stimuli on the center key and form-comparison stimuli on the left key of a three-key chamber. A control group was trained with all stimuli appearing on the same (left) key. Training also involved concurrent hue- and form-identity successive matching with the same spatial location arrangement as each group’s respective hue–form task. Later, nonreinforced form–hue (symmetry) probes structured in the same way as the baseline trials were given. Of the six birds in each group, five trained with different locations and two trained with constant location responded more to the reverse of baseline positive hue–form combinations than to negative ones in testing. Results confirm the prediction from Urcuioli’s (2008) theory that symmetry should emerge even with varying spatial locations, as long as functional stimuli are held constant. PMID:23703090

  18. Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

    Directory of Open Access Journals (Sweden)

    Marieke Elise Thurlings

    2014-09-01

    Full Text Available Gaze-independent event-related potential (ERP based brain-computer interfaces (BCIs yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1 bimodal versus unimodal stimuli, (2 location-congruent versus location-incongruent bimodal stimuli, and (3 attending to both modalities versus to either one modality. We observed an enhanced bimodal (compared to unimodal P300 tAUC, which appeared to be positively affected by location-congruency (p=.056 and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance.

  19. Biased towards food: Electrophysiological evidence for biased attention to food stimuli.

    Science.gov (United States)

    Kumar, Sanjay; Higgs, Suzanne; Rutters, Femke; Humphreys, Glyn W

    2016-12-01

    We investigated the neural mechanisms involved in bias for food stimuli in our visual environment using event related lateralized (ERL) responses. The participants were presented with a cue (food or non-food item) to either identify or hold in working memory. Subsequently, they had to search for a target in a 2-item display where target and distractor stimuli were each flanked by a picture of a food or a non-food item. The behavioural data showed that performance was strongly affected by food cues, especially when food was held in WM compared to when the cues were merely identified. The temporal dynamics of electrophysiological measures of attention (the N1pc and N2pc) showed that the orienting of attention towards food stimuli was associated with two different mechanisms; an early stage of attentional suppression followed by a later stage of attentional orienting towards food stimuli. In contrast, non-food cues were associated only with the guidance of attention to or away from cued stimuli on valid and invalid trials. The results demonstrate that food items, perhaps due to their motivational significance modulate the early orienting of attention, including an initial suppressive response to food items. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Ideological reactivity: Political conservatism and brain responsivity to emotional and neutral stimuli.

    Science.gov (United States)

    Tritt, Shona M; Peterson, Jordan B; Page-Gould, Elizabeth; Inzlicht, Michael

    2016-12-01

    Conservatives are often thought to have a negativity bias-responding more intensely to negative than positive information. Yet, recent research has found that greater endorsement of conservative beliefs follows from both positive and negative emotion inductions. This suggests that the role of affect in political thought may not be restricted to negative valence, and more attention should be given to how conservatives and liberals respond to a wider range of stimulation. In this vein, we examined neural responses to a full range of affective stimuli, allowing us to examine how self-reported ideology moderated these responses. Specifically, we explored the relationship between political orientation and 2 event-related potentials (1 late and 1 early) previously shown to covary with the subjective motivational salience of stimuli-in response to photographs with standardized ratings of arousal and valence. At late time points, conservatives exhibited sustained heightened reactivity, compared with liberals, specifically in response to relatively unarousing and neutral stimuli. At early time points, conservatives exhibited somewhat enhanced neural activity in response to all stimulus types compared with liberals. These results may suggest that conservatives experience a wide variety of stimuli in their environment with increased motivational salience, including positive, neutral, and low-arousal stimuli. No effects of valence were found in this investigation. Such findings have implications for the development and refinement of psychological conceptions of political orientation. (PsycINFO Database Record

  1. Relationship between Sympathetic Skin Responses and Auditory Hypersensitivity to Different Auditory Stimuli.

    Science.gov (United States)

    Kato, Fumi; Iwanaga, Ryoichiro; Chono, Mami; Fujihara, Saori; Tokunaga, Akiko; Murata, Jun; Tanaka, Koji; Nakane, Hideyuki; Tanaka, Goro

    2014-07-01

    [Purpose] Auditory hypersensitivity has been widely reported in patients with autism spectrum disorders. However, the neurological background of auditory hypersensitivity is currently not clear. The present study examined the relationship between sympathetic nervous system responses and auditory hypersensitivity induced by different types of auditory stimuli. [Methods] We exposed 20 healthy young adults to six different types of auditory stimuli. The amounts of palmar sweating resulting from the auditory stimuli were compared between groups with (hypersensitive) and without (non-hypersensitive) auditory hypersensitivity. [Results] Although no group × type of stimulus × first stimulus interaction was observed for the extent of reaction, significant type of stimulus × first stimulus interaction was noted for the extent of reaction. For an 80 dB-6,000 Hz stimulus, the trends for palmar sweating differed between the groups. For the first stimulus, the variance became larger in the hypersensitive group than in the non-hypersensitive group. [Conclusion] Subjects who regularly felt excessive reactions to auditory stimuli tended to have excessive sympathetic responses to repeated loud noises compared with subjects who did not feel excessive reactions. People with auditory hypersensitivity may be classified into several subtypes depending on their reaction patterns to auditory stimuli.

  2. Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

    Science.gov (United States)

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

    2014-01-01

    Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance. PMID:25249947

  3. Experimental and theoretical investigations in stimuli responsive dendrimer-based assemblies

    Science.gov (United States)

    Molla, Mijanur Rahaman; Rangadurai, Poornima; Pavan, Giovanni M.; Thayumanavan, S.

    2015-02-01

    Stimuli-responsive macromolecular assemblies are of great interest in drug delivery applications, as it holds the promise to keep the drug molecules sequestered under one set of conditions and release them under another. The former set of conditions could represent circulation, while the latter could represent a disease location. Over the past two decades, sizeable contributions to this field have come from dendrimers, which along with their monodispersity, provide great scope for structural modifications at the molecular level. In this paper, we briefly discuss the various synthetic strategies that have been developed so far to obtain a range of functional dendrimers. We then discuss the design strategies utilized to introduce stimuli responsive elements within the dendritic architecture. The stimuli itself are broadly classified into two categories, viz. extrinsic and intrinsic. Extrinsic stimuli are externally induced such as temperature and light variations, while intrinsic stimuli involve physiological aberrations such as variations in pH, redox conditions, proteins and enzyme concentrations in pathological tissues. Furthermore, the unique support from molecular dynamics (MD) simulations has been highlighted. MD simulations have helped back many of the observations made from assembly formation properties to rationalized the mechanism of drug release and this has been illustrated with discussions on G4 PPI (Poly propylene imine) dendrimers and biaryl facially amphiphilic dendrimers. The synergy that exists between experimental and theoretical studies open new avenues for the use of dendrimers as versatile drug delivery systems.

  4. Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli.

    Science.gov (United States)

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

    2014-01-01

    Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components' tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance.

  5. Multisensory stimuli elicit altered oscillatory brain responses at gamma frequencies in patients with schizophrenia

    Directory of Open Access Journals (Sweden)

    David B. Stone

    2014-11-01

    Full Text Available Deficits in auditory and visual unisensory responses are well documented in patients with schizophrenia; however, potential abnormalities elicited from multisensory audio-visual stimuli are less understood. Further, schizophrenia patients have shown abnormal patterns in task-related and task-independent oscillatory brain activity, particularly in the gamma frequency band. We examined oscillatory responses to basic unisensory and multisensory stimuli in schizophrenia patients (N = 46 and healthy controls (N = 57 using magnetoencephalography (MEG. Time-frequency decomposition was performed to determine regions of significant changes in gamma band power by group in response to unisensory and multisensory stimuli relative to baseline levels. Results showed significant behavioral differences between groups in response to unisensory and multisensory stimuli. In addition, time-frequency analysis revealed significant decreases and increases in gamma-band power in schizophrenia patients relative to healthy controls, which emerged both early and late over both sensory and frontal regions in response to unisensory and multisensory stimuli. Unisensory gamma-band power predicted multisensory gamma-band power differently by group. Furthermore, gamma-band power in these regions predicted performance in select measures of the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS test battery differently by group. These results reveal a unique pattern of task-related gamma-band power in schizophrenia patients relative to controls that may indicate reduced inhibition in combination with impaired oscillatory mechanisms in patients with schizophrenia.

  6. The spatial structure of stimuli shapes the timescale of correlations in population spiking activity.

    Science.gov (United States)

    Litwin-Kumar, Ashok; Chacron, Maurice J; Doiron, Brent

    2012-01-01

    Throughout the central nervous system, the timescale over which pairs of neural spike trains are correlated is shaped by stimulus structure and behavioral context. Such shaping is thought to underlie important changes in the neural code, but the neural circuitry responsible is largely unknown. In this study, we investigate a stimulus-induced shaping of pairwise spike train correlations in the electrosensory system of weakly electric fish. Simultaneous single unit recordings of principal electrosensory cells show that an increase in the spatial extent of stimuli increases correlations at short (≈ 10 ms) timescales while simultaneously reducing correlations at long (≈ 100 ms) timescales. A spiking network model of the first two stages of electrosensory processing replicates this correlation shaping, under the assumptions that spatially broad stimuli both saturate feedforward afferent input and recruit an open-loop inhibitory feedback pathway. Our model predictions are experimentally verified using both the natural heterogeneity of the electrosensory system and pharmacological blockade of descending feedback projections. For weak stimuli, linear response analysis of the spiking network shows that the reduction of long timescale correlation for spatially broad stimuli is similar to correlation cancellation mechanisms previously suggested to be operative in mammalian cortex. The mechanism for correlation shaping supports population-level filtering of irrelevant distractor stimuli, thereby enhancing the population response to relevant prey and conspecific communication inputs.

  7. The spatial structure of stimuli shapes the timescale of correlations in population spiking activity.

    Directory of Open Access Journals (Sweden)

    Ashok Litwin-Kumar

    Full Text Available Throughout the central nervous system, the timescale over which pairs of neural spike trains are correlated is shaped by stimulus structure and behavioral context. Such shaping is thought to underlie important changes in the neural code, but the neural circuitry responsible is largely unknown. In this study, we investigate a stimulus-induced shaping of pairwise spike train correlations in the electrosensory system of weakly electric fish. Simultaneous single unit recordings of principal electrosensory cells show that an increase in the spatial extent of stimuli increases correlations at short (≈ 10 ms timescales while simultaneously reducing correlations at long (≈ 100 ms timescales. A spiking network model of the first two stages of electrosensory processing replicates this correlation shaping, under the assumptions that spatially broad stimuli both saturate feedforward afferent input and recruit an open-loop inhibitory feedback pathway. Our model predictions are experimentally verified using both the natural heterogeneity of the electrosensory system and pharmacological blockade of descending feedback projections. For weak stimuli, linear response analysis of the spiking network shows that the reduction of long timescale correlation for spatially broad stimuli is similar to correlation cancellation mechanisms previously suggested to be operative in mammalian cortex. The mechanism for correlation shaping supports population-level filtering of irrelevant distractor stimuli, thereby enhancing the population response to relevant prey and conspecific communication inputs.

  8. Narcissism dimensions differentially moderate selective attention to evaluative stimuli in incarcerated offenders

    Science.gov (United States)

    Krusemark, Elizabeth A.; Lee, Christopher; Newman, Joseph P.

    2014-01-01

    Narcissistic personality disorder is associated with distinguishing traits including self-enhancement, arrogance and intense reactivity to ego threat. Theoretical accounts of narcissism suggest these heterogeneous behaviors reflect a defensive motivational style that functions to both uphold and protect the self-concept. However, the notion that narcissism can be characterized by grandiose and vulnerable dimensions raises the possibility that these diverse behaviors represent distinct expressions of narcissistic defensiveness. The present study examined whether both dimensions exhibit a general defensive style marked by selective attention to evaluative stimuli or are differentially associated with selective attention to positive and negative information, respectively. Using a dot probe task consisting of valenced and neutral trait adjectives, we evaluated these hypotheses in a group of male offenders. Results indicated that vulnerable narcissism was associated with attention biases for both positive and negative stimuli, though the dimension was further distinguished by disengagement difficulties and a greater recognition memory bias in response to negative words. Conversely, grandiose narcissism was associated with increased accuracy when attending to positive stimuli and directing attention away from negative stimuli. Overall, these findings suggest narcissistic individuals share motivated selective attention in response to evaluative stimuli, while simultaneously highlighting important phenotypic differences between grandiose and vulnerable dimensions. PMID:25330183

  9. The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference.

    Science.gov (United States)

    Zhang, Li; Fang, Qiaochu; Gabriel, Florence C; Szücs, Dénes

    2014-01-01

    Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference.

  10. Gestalt Perceptual Organization of Visual Stimuli Captures Attention Automatically: Electrophysiological Evidence.

    Science.gov (United States)

    Marini, Francesco; Marzi, Carlo A

    2016-01-01

    The visual system leverages organizational regularities of perceptual elements to create meaningful representations of the world. One clear example of such function, which has been formalized in the Gestalt psychology principles, is the perceptual grouping of simple visual elements (e.g., lines and arcs) into unitary objects (e.g., forms and shapes). The present study sought to characterize automatic attentional capture and related cognitive processing of Gestalt-like visual stimuli at the psychophysiological level by using event-related potentials (ERPs). We measured ERPs during a simple visual reaction time task with bilateral presentations of physically matched elements with or without a Gestalt organization. Results showed that Gestalt (vs. non-Gestalt) stimuli are characterized by a larger N2pc together with enhanced ERP amplitudes of non-lateralized components (N1, N2, P3) starting around 150 ms post-stimulus onset. Thus, we conclude that Gestalt stimuli capture attention automatically and entail characteristic psychophysiological signatures at both early and late processing stages. Highlights We studied the neural signatures of the automatic processes of visual attention elicited by Gestalt stimuli. We found that a reliable early correlate of attentional capture turned out to be the N2pc component. Perceptual and cognitive processing of Gestalt stimuli is associated with larger N1, N2, and P3.

  11. Chemosensory responses to chemical and visual stimuli in five species of colubrid snakes

    Directory of Open Access Journals (Sweden)

    Anthony J. Saviola

    2012-07-01

    Full Text Available Snakes utilize chemical and visual stimuli during predation, however the emphasis on these cues and which cues are used to initiate predation varies among species. For example, rattlesnakes using the ambush strategy rely on chemical cues to locate an ambush station, then visual and thermal cues to initiate envenomating strikes, then chemical cues again to track prey. By contrast, many natricine snakes use chemical cues to initiate predation, increasing the rate of tongue flicking regardless of whether visual cues are present. The present study examined the individual and interactive effects of chemical and visual stimuli of prey on the predatory behavior of five snake taxa representing three feeding guilds. Bull snakes (Pituophis catenifer, Eastern Corn snakes (Pantherophis guttatus, and Midland Rat snakes (Scotophis spiloides have a diet primarily consisting of mammals; Western Fox snakes (Mintonius vulpina prey primarily on bird eggs; and Common Kingsnakes (Lampropeltis getula prey equally on mammals and reptiles. Three patterns of response to chemical and visual stimuli of the test prey (Mus musculus were observed. Mammal specialists responded to chemical cues. Fox snakes responded to visual cues, but not to chemical cues. Kingsnakes exhibited increased rates of tongue flicking in response to both chemical and visual stimuli. This study suggests correlations between the evolution of prey preference, foraging ecology and the utilization of chemical or visual stimuli by snakes.

  12. Vergence and accommodation to multiple-image-plane stereoscopic displays: ``real world'' responses with practical image-plane separations?

    Science.gov (United States)

    MacKenzie, Kevin J.; Dickson, Ruth A.; Watt, Simon J.

    2012-01-01

    Conventional stereoscopic displays present images on a single focal plane. The resulting mismatch between the stimuli to the eyes' focusing response (accommodation) and to convergence causes fatigue and poor stereo performance. One solution is to distribute image intensity across a number of widely spaced image planes--a technique referred to as depth filtering. Previously, we found this elicits accurate, continuous monocular accommodation responses with image-plane separations as large as 1.1 Diopters (D, the reciprocal of distance in meters), suggesting that a small number of image planes could eliminate vergence-accommodation conflicts over a large range of simulated distances. Evidence exists, however, of systematic differences between accommodation responses to binocular and monocular stimuli when the stimulus to accommodation is degraded, or at an incorrect distance. We examined the minimum image-plane spacing required for accurate accommodation to binocular depth-filtered images. We compared accommodation and vergence responses to changes in depth specified by depth filtering, using image-plane separations of 0.6 to 1.2 D, and equivalent real stimuli. Accommodation responses to real and depth-filtered stimuli were equivalent for image-plane separations of ~0.6 to 0.9 D, but differed thereafter. We conclude that depth filtering can be used to precisely match accommodation and vergence demand in a practical stereoscopic display.

  13. Bumblebees require visual pollen stimuli to initiate and multimodal stimuli to complete a full behavioral sequence in close?range flower orientation

    OpenAIRE

    Wilmsen, Saskia; Gottlieb, Robin; Robert R Junker; Lunau, Klaus

    2017-01-01

    Abstract Flower visits are complex encounters, in which animals are attracted by floral signals, guided toward the site of the first physical contact with a flower, land, and finally take up floral rewards. At close range, signals of stamens and pollen play an important role to facilitate flower handling in bees, yet the pollen stimuli eliciting behavioral responses are poorly known. In this study, we test the response of flower?naive bumblebees (Bombus terrestris) toward single and multimoda...

  14. Intermittent electrical stimuli for guidance of human mesenchymal stem cell lineage commitment towards neural-like cells on electroconductive substrates.

    Science.gov (United States)

    Thrivikraman, Greeshma; Madras, Giridhar; Basu, Bikramjit

    2014-08-01

    In the context of the role of multiple physical factors in dictating stem cell fate, the present paper demonstrates the effectiveness of the intermittently delivered external electric field stimulation towards switching the stem cell fate to specific lineage, when cultured in the absence of biochemical growth factors. In particular, our findings present the ability of human mesenchymal stem cells (hMSCs) to respond to the electric stimuli by adopting extended neural-like morphology on conducting polymeric substrates. Polyaniline (PANI) is selected as the model system to demonstrate this effect, as the electrical conductivity of the polymeric substrates can be systematically tailored over a broad range (10(-9) to 10 S/cm) from highly insulating to conducting by doping with varying concentrations (10(-5) to 1 m) of HCl. On the basis of the culture protocol involving the systematic delivery of intermittent electric field (dc) stimulation, the parametric window of substrate conductivity and electric field strength was established to promote significant morphological extensions, with minimal cellular damage. A time dependent morphological change in hMSCs with significant filopodial elongation was observed after 7 days of electrically stimulated culture. Concomitant with morphological changes, a commensurate increase in the expression of neural lineage commitment markers such as nestin and βIII tubulin was recorded from hMSCs grown on highly conducting substrates, as revealed from the mRNA expression analysis using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) as well as by immune-fluorescence imaging. Therefore, the present work establishes the key role of intermittent and systematic delivery of electric stimuli as guidance cues in promoting neural-like differentiation of hMSCs, when grown on electroconductive substrates.

  15. The catechol-O-methyltransferase (COMT val158met polymorphism affects brain responses to repeated painful stimuli.

    Directory of Open Access Journals (Sweden)

    Marco L Loggia

    Full Text Available Despite the explosion of interest in the genetic underpinnings of individual differences in pain sensitivity, conflicting findings have emerged for most of the identified "pain genes". Perhaps the prime example of this inconsistency is represented by catechol-O-methyltransferase (COMT, as its substantial association to pain sensitivity has been reported in various studies, but rejected in several others. In line with findings from behavioral studies, we hypothesized that the effect of COMT on pain processing would become apparent only when the pain system was adequately challenged (i.e., after repeated pain stimulation. In the present study, we used functional Magnetic Resonance Imaging (fMRI to investigate the brain response to heat pain stimuli in 54 subjects genotyped for the common COMT val158met polymorphism (val/val = n 22, val/met = n 20, met/met = n 12. Met/met subjects exhibited stronger pain-related fMRI signals than val/val in several brain structures, including the periaqueductal gray matter, lingual gyrus, cerebellum, hippocampal formation and precuneus. These effects were observed only for high intensity pain stimuli after repeated administration. In spite of our relatively small sample size, our results suggest that COMT appears to affect pain processing. Our data demonstrate that the effect of COMT on pain processing can be detected in presence of 1 a sufficiently robust challenge to the pain system to detect a genotype effect, and/or 2 the recruitment of pain-dampening compensatory mechanisms by the putatively more pain sensitive met homozygotes. These findings may help explain the inconsistencies in reported findings of the impact of COMT in pain regulation.

  16. Procedure to validate sexual stimuli: reliability and validity of a set of sexual stimuli in a sample of young colombian heterosexual males

    Directory of Open Access Journals (Sweden)

    Pablo Vallejo-Medina

    2017-01-01

    Full Text Available Penile plethysmography – or phallometric assessment – is a very relevant evaluation for sexual health. The objective of this research is to suggest a guideline to validate sexual stimuli and validate a set of sexual stimuli to assess “normative” sexual behavior in Colombian young heterosexual men. Six videos of 3:15 minute-long were used. A total of 24 men were assessed. Objective sexual arousal, the International Index of Erectile Function-5, Self-Assessment Manikin, Multidimensional Scale to Assess Subjective Sexual Arousal and socio-psycho-sexual questions were used. The results showed three sexual excerpts which were clearly superior to the others – something discordant with the subjective opinion of researchers. These three sexual excerpts generated internally consistent measurements; moreover, good indicators of external validity have been observed with statistically significant differences as expected. Furthermore, with a small healthy Colombian young population, it has been shown that the three stimuli produce objective sexual arousal if used together.

  17. Sub-Second Temporal Integration of Vibro-Tactile Stimuli: Intervals between Adjacent, Weak, and Within-Channel Stimuli Are Underestimated

    Directory of Open Access Journals (Sweden)

    Scinob Kuroki

    2017-07-01

    Full Text Available Tactile estimation of sub-second time is essential for correct recognition of sensory inputs and dexterous manipulation of objects. Despite our intuitive understanding that time is robustly estimated in any situation, tactile sub-second time is altered by, for example, body movement, similar to how visual time is modulated by eye movement. The effects of simpler factors, such as stimulus location, intensity, and frequency, have also been reported in temporal tasks in other modalities, but their effects on tactile sub-second interval estimation remain obscure. Here, we were interested in whether a perceived short interval presented by tactile stimuli is altered only by changing stimulus features. The perceived interval between a pair of stimuli presented on the same finger apparently became short relative to that on different fingers; that of a weak-intensity pair relative to that of a pair with stronger intensity was decreased; and that of a pair with the same frequency relative to one with different frequencies was underestimated. These findings can be ascribed to errors in encoding temporal relationships: nearby-space/weak-intensity/similar-frequency stimuli presented within a short time difference are likely to be integrated into a single event and lead to relative time compression.

  18. Dual-stimuli responsive and reversibly activatable theranostic nanoprobe for precision tumor-targeting and fluorescence-guided photothermal therapy

    Science.gov (United States)

    Zhao, Xu; Yang, Cheng-Xiong; Chen, Li-Gong; Yan, Xiu-Ping

    2017-05-01

    The integrated functions of diagnostics and therapeutics make theranostics great potential for personalized medicine. Stimulus-responsive therapy allows spatial control of therapeutic effect only in the site of interest, and offers promising opportunities for imaging-guided precision therapy. However, the imaging strategies in previous stimulus-responsive therapies are `always on' or irreversible `turn on' modality, resulting in poor signal-to-noise ratios or even `false positive' results. Here we show the design of dual-stimuli-responsive and reversibly activatable nanoprobe for precision tumour-targeting and fluorescence-guided photothermal therapy. We fabricate the nanoprobe from asymmetric cyanine and glycosyl-functionalized gold nanorods (AuNRs) with matrix metalloproteinases (MMPs)-specific peptide as a linker to achieve MMPs/pH synergistic and pH reversible activation. The unique activation and glycosyl targetibility makes the nanoprobe bright only in tumour sites with negligible background, while AuNRs and asymmetric cyanine give synergistic photothermal effect. This work paves the way to designing efficient nanoprobes for precision theranostics.

  19. Image-Word Pairing-Congruity Effect on Affective Responses

    Science.gov (United States)

    Sanabria Z., Jorge C.; Cho, Youngil; Sambai, Ami; Yamanaka, Toshimasa

    The present study explores the effects of familiarity on affective responses (pleasure and arousal) to Japanese ad elements, based on the schema incongruity theory. Print ads showing natural scenes (landscapes) were used to create the stimuli (images and words). An empirical study was conducted to measure subjects' affective responses to image-word combinations that varied in terms of incongruity. The level of incongruity was based on familiarity levels, and was statistically determined by a variable called ‘pairing-congruity status’. The tested hypothesis proposed that even highly familiar image-word combinations, when combined incongruously, would elicit strong affective responses. Subjects assessed the stimuli using bipolar scales. The study was effective in tracing interactions between familiarity, pleasure and arousal, although the incongruous image-word combinations did not elicit the predicted strong effects on pleasure and arousal. The results suggest a need for further research incorporating kansei (i.e., creativity) into the process of stimuli selection.

  20. Early somatosensory event-related potentials reveal attentional bias for internal stimuli in social anxiety.

    Science.gov (United States)

    Kanai, Yoshihiro; Nittono, Hiroshi; Kubo, Kenta; Sasaki-Aoki, Shoko; Iwanaga, Makoto

    2012-03-01

    The present study used event-related brain potentials (ERPs) to investigate allocation of attentional resources to internal and external stimuli in individuals with social anxiety. High and low socially anxious individuals were presented with depictions of various facial expressions or household objects, followed by an internal (vibration presented to the finger) or external probe (the letter "E"). Participants were told that the vibration signals physiological changes and were asked to detect both probes. High socially anxious individuals showed larger front-central N140 amplitudes in response to vibratory internal probes as compared to non-anxious controls. ERPs elicited by picture stimuli and external probes and reaction times in response to both probe types did not differ between high and low social anxiety individuals. Early somatosensory ERPs reveal an attentional bias for internal stimuli that does not appear in overt behavior.

  1. A PDA platform for offline processing and streaming of stimuli for cochlear implant research.

    Science.gov (United States)

    Ali, Hussnain; Lobo, Arthur P; Loizou, Philipos C

    2011-01-01

    A PDA-based research platform has been developed for implementing novel speech processing strategies and conducting psychophysical experiments with cochlear implant (CI) research that do not necessarily require real-time processing. The developed interface streams stimuli pulses to a CI unit in an offline mode from a Personal Computer via PDA platform using Windows Sockets (WINSOCK). Front-end of the application is run in MATLAB where stimuli pulses are created. Winsock establishes a TCP/IP connection with the PDA and starts the transmission of stimuli data. Server application installed on the PDA reads the stimulation data and forwards it to the SDIO board in packets where it is forwarded to the cochlear implant unit and pulses are then played in realtime. Versatility and flexibility are the key characteristics of the platform for easy implementation and testing of a wide range of applications and experiments without advanced programming skills.

  2. Exploring Strategies for Classification of External Stimuli Using Statistical Features of the Plant Electrical Response

    CERN Document Server

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

    2016-01-01

    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), Sulphuric 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.

  3. Conditioning with compound stimuli in Drosophila melanogaster in the flight simulator.

    Science.gov (United States)

    Brembs, B; Heisenberg, M

    2001-08-01

    Short-term memory in Drosophila melanogaster operant visual learning in the flight simulator is explored using patterns and colours as a compound stimulus. Presented together during training, the two stimuli accrue the same associative strength whether or not a prior training phase rendered one of the two stimuli a stronger predictor for the reinforcer than the other (no blocking). This result adds Drosophila to the list of other invertebrates that do not exhibit the robust vertebrate blocking phenomenon. Other forms of higher-order learning, however, were detected: a solid sensory preconditioning and a small second-order conditioning effect imply that associations between the two stimuli can be formed, even if the compound is not reinforced.

  4. A reversible multi-stimuli-responsive fluorescence probe and the design for combinational logic gate operations.

    Science.gov (United States)

    Xia, Hongyan; Xu, Yangyang; Yang, Guang; Jiang, Hao; Zou, Gang; Zhang, Qijin

    2014-02-01

    Here, a novel multi-stimuli-responsive fluorescence probe is developed by incorporating spiropyran group into the coumarin-substituted polydiacetylene (PDA) vesicles. The fluorescence of PDA can be turned on upon heating, and can be quenched upon exposure to UV light irradiation or pH stimuli owing to the fluorescene resonance energy transfer (FRET) between the red-phase PDA and the open merocyanine (MC) form of spiropyran. Moreover, we have designed and experimentally realized a set of logic gate operations for the first time based on the fluorescence modulation of the designed system upon thermal, photo, and pH stimuli. This novel type of resettable logic gates augur well for practical applications in information storage, optical recording, and sensing in complicated microenvironments. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Fractional Diffusion Based Modelling and Prediction of Human Brain Response to External Stimuli

    Directory of Open Access Journals (Sweden)

    Hamidreza Namazi

    2015-01-01

    Full Text Available Human brain response is the result of the overall ability of the brain in analyzing different internal and external stimuli and thus making the proper decisions. During the last decades scientists have discovered more about this phenomenon and proposed some models based on computational, biological, or neuropsychological methods. Despite some advances in studies related to this area of the brain research, there were fewer efforts which have been done on the mathematical modeling of the human brain response to external stimuli. This research is devoted to the modeling and prediction of the human EEG signal, as an alert state of overall human brain activity monitoring, upon receiving external stimuli, based on fractional diffusion equations. The results of this modeling show very good agreement with the real human EEG signal and thus this model can be used for many types of applications such as prediction of seizure onset in patient with epilepsy.

  6. Monetary reward modulates task-irrelevant perceptual learning for invisible stimuli.

    Directory of Open Access Journals (Sweden)

    David Pascucci

    Full Text Available Task Irrelevant Perceptual Learning (TIPL shows that the brain's discriminative capacity can improve also for invisible and unattended visual stimuli. It has been hypothesized that this form of "unconscious" neural plasticity is mediated by an endogenous reward mechanism triggered by the correct task performance. Although this result has challenged the mandatory role of attention in perceptual learning, no direct evidence exists of the hypothesized link between target recognition, reward and TIPL. Here, we manipulated the reward value associated with a target to demonstrate the involvement of reinforcement mechanisms in sensory plasticity for invisible inputs. Participants were trained in a central task associated with either high or low monetary incentives, provided only at the end of the experiment, while subliminal stimuli were presented peripherally. Our results showed that high incentive-value targets induced a greater degree of perceptual improvement for the subliminal stimuli, supporting the role of reinforcement mechanisms in TIPL.

  7. Influence of prolonged optic flow stimuli on spontaneous activities of cat PMLS neurons

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Changes in neuronal spontaneous acti