WorldWideScience

Sample records for vibrotactile stimuli delivered

  1. The effect of real-time vibrotactile feedback delivered through an augmented fork on eating rate, satiation, and food intake.

    Science.gov (United States)

    Hermans, Roel C J; Hermsen, Sander; Robinson, Eric; Higgs, Suzanne; Mars, Monica; Frost, Jeana H

    2017-06-01

    Eating rate is a basic determinant of appetite regulation, as people who eat more slowly feel sated earlier and eat less. Without assistance, eating rate is difficult to modify due to its automatic nature. In the current study, participants used an augmented fork that aimed to decelerate their rate of eating. A total of 114 participants were randomly assigned to the Feedback Condition (FC), in which they received vibrotactile feedback from their fork when eating too fast (i.e., taking more than one bite per 10 s), or a Non-Feedback Condition (NFC). Participants in the FC took fewer bites per minute than did those in the NFC. Participants in the FC also had a higher success ratio, indicating that they had significantly more bites outside the designated time interval of 10 s than did participants in the NFC. A slower eating rate, however, did not lead to a significant reduction in the amount of food consumed or level of satiation. These findings indicate that real-time vibrotactile feedback delivered through an augmented fork is capable of reducing eating rate, but there is no evidence from this study that this reduction in eating rate is translated into an increase in satiation or reduction in food consumption. Overall, this study shows that real-time vibrotactile feedback may be a viable tool in interventions that aim to reduce eating rate. The long-term effectiveness of this form of feedback on satiation and food consumption, however, awaits further investigation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effects of Vibrotactile Stimulation During Virtual Sandboarding

    DEFF Research Database (Denmark)

    Lind, Stine; Thomsen, Lui; Egebjerg, Mie

    2016-01-01

    This poster details a within-subjects study (n=17) investigating the effects of vibrotactile stimulation on illusory self-motion, presence and perceived realism during an interactive sandboarding simulation. Vibrotactile feedback was delivered using a low frequency audio transducer mounted...... underneath the board. The study compared three conditions: no vibration, constant vibration and dynamic vibration. The results suggest that constant vibrotactile feedback led to significantly more compelling self-motion illusions and a higher degree of perceived realism, than the condition devoid...

  3. Effects of acoustical stimuli delivered through hearing aids on tinnitus.

    Science.gov (United States)

    Sweetow, Robert W; Sabes, Jennifer Henderson

    2010-01-01

    range of preferences observed for fractal settings, with most participants preferring fractals with a slow or medium tempo and restricted dynamic range. The majority (86%) indicated that it was easier to relax while listening to fractal signals. Participants had preferences for certain programs and fractal characteristics. Although seven participants rated the noise-only condition as providing the least tinnitus annoyance, only two opted to have noise only as a program during the field trial, and none selected the noise-only condition as the preferred setting. Furthermore, while all four of the experienced hearing aid users selected noise as producing the least annoying tinnitus in the laboratory, only one selected it for field wear. Tinnitus Handicap Inventory and Tinnitus Reaction Questionnaire scores were improved over the course of the 6 mo trial, with clinically significant improvements occurring for over half of the participants on at least one of the measures. The results suggest that use of acoustic stimuli, particularly fractal tones, delivered though hearing aids can provide amplification while allowing for relief for some tinnitus sufferers. It is important to recognize, however, that tinnitus management procedures need to be supplemented with appropriate counseling. American Academy of Audiology.

  4. Feeling the Beat: Bouncing Synchronization to Vibrotactile Music in Hearing and Early Deaf People

    Directory of Open Access Journals (Sweden)

    Pauline Tranchant

    2017-09-01

    Full Text Available The ability to dance relies on the ability to synchronize movements to a perceived musical beat. Typically, beat synchronization is studied with auditory stimuli. However, in many typical social dancing situations, music can also be perceived as vibrations when objects that generate sounds also generate vibrations. This vibrotactile musical perception is of particular relevance for deaf people, who rely on non-auditory sensory information for dancing. In the present study, we investigated beat synchronization to vibrotactile electronic dance music in hearing and deaf people. We tested seven deaf and 14 hearing individuals on their ability to bounce in time with the tempo of vibrotactile stimuli (no sound delivered through a vibrating platform. The corresponding auditory stimuli (no vibrations were used in an additional condition in the hearing group. We collected movement data using a camera-based motion capture system and subjected it to a phase-locking analysis to assess synchronization quality. The vast majority of participants were able to precisely time their bounces to the vibrations, with no difference in performance between the two groups. In addition, we found higher performance for the auditory condition compared to the vibrotactile condition in the hearing group. Our results thus show that accurate tactile-motor synchronization in a dance-like context occurs regardless of auditory experience, though auditory-motor synchronization is of superior quality.

  5. Presenting directions with a vibrotactile torso display

    NARCIS (Netherlands)

    Erp, J.B.F. van

    2005-01-01

    Vibrotactile displays covering the torso present spatial information in an intuitive way since the stimuli are directly mapped to the body coordinates; left is left, front is front, etc. The present study investigated the direction in the horizontal plane to which a specific torso location is mapped

  6. Vibrotactile Feedback for Brain-Computer Interface Operation

    Directory of Open Access Journals (Sweden)

    Febo Cincotti

    2007-01-01

    Full Text Available To be correctly mastered, brain-computer interfaces (BCIs need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (including 3 with spinal cord injury, we compared vibrotactile and visual feedback, addressing: (I the feasibility of subjects' training to master their EEG rhythms using tactile feedback; (II the compatibility of this form of feedback in presence of a visual distracter; (III the performance in presence of a complex visual task on the same (visual or different (tactile sensory channel. The stimulation protocol we developed supports a general usage of the tactors; preliminary experimentations. All studies indicated that the vibrotactile channel can function as a valuable feedback modality with reliability comparable to the classical visual feedback. Advantages of using a vibrotactile feedback emerged when the visual channel was highly loaded by a complex task. In all experiments, vibrotactile feedback felt, after some training, more natural for both controls and SCI users.

  7. Progress in vibrotactile threshold evaluation techniques: a review.

    Science.gov (United States)

    Gandhi, Minu Shikha; Sesek, Richard; Tuckett, Robert; Bamberg, Stacy J Morris

    2011-01-01

    Vibrotactile threshold (VT) testing has been used for nearly a century to investigate activation of human somatosensory pathways. This use of vibrotactile stimuli provides a versatile tool for detecting peripheral neuropathies, and has been broadly used for investigation of carpal tunnel syndrome. New applications include investigation of drug-induced neuropathies and diabetes-related neuropathies. As a feedback device, the vibrotactile stimuli could be used as an information delivery system for rehabilitative feedback devices for upper limb musculoskeletal disorders or as information channels for the visually impaired. This review provides a comprehensive review of the advancement in VT measurement techniques over time and a comparison of these techniques in terms of various hardware features used and the testing protocols implemented. The advantages and limitations of these methods have been discussed along with specific recommendations for their implementation and suggestions for incorporation into clinical practice. Copyright © 2011 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  8. Multisensory interaction in vibrotactile detection and discrimination of amplitude modulation

    DEFF Research Database (Denmark)

    Teodorescu, Kinneret; Bouchigny, Sylvain; Hoffmann, Pablo F.

    2011-01-01

    Perception of vibration during drilling demands integration of haptic and auditory information with force information. In this study we explored the ability to detect and discriminate changes in vibrotactile stimuli amplitude based either on purely haptic feedback or together with congruent synth...

  9. Neuromorphic Vibrotactile Stimulation of Fingertips for Encoding Object Stiffness in Telepresence Sensory Substitution and Augmentation Applications

    Directory of Open Access Journals (Sweden)

    Francesca Sorgini

    2018-01-01

    Full Text Available We present a tactile telepresence system for real-time transmission of information about object stiffness to the human fingertips. Experimental tests were performed across two laboratories (Italy and Ireland. In the Italian laboratory, a mechatronic sensing platform indented different rubber samples. Information about rubber stiffness was converted into on-off events using a neuronal spiking model and sent to a vibrotactile glove in the Irish laboratory. Participants discriminated the variation of the stiffness of stimuli according to a two-alternative forced choice protocol. Stiffness discrimination was based on the variation of the temporal pattern of spikes generated during the indentation of the rubber samples. The results suggest that vibrotactile stimulation can effectively simulate surface stiffness when using neuronal spiking models to trigger vibrations in the haptic interface. Specifically, fractional variations of stiffness down to 0.67 were significantly discriminated with the developed neuromorphic haptic interface. This is a performance comparable, though slightly worse, to the threshold obtained in a benchmark experiment evaluating the same set of stimuli naturally with the own hand. Our paper presents a bioinspired method for delivering sensory feedback about object properties to human skin based on contingency–mimetic neuronal models, and can be useful for the design of high performance haptic devices.

  10. Hand position-dependent modulation of errors in vibrotactile temporal order judgments

    DEFF Research Database (Denmark)

    Ritterband-Rosenbaum, Anina; Hermosillo, Robert; Kroliczak, Gregory

    2014-01-01

    this confounded information is processed in the brain is poorly understood. In the present set of experiments, we addressed this knowledge gap by using singlepulse transcranial magnetic stimulation (TMS) to disrupt processing in the right or left posterior parietal cortex (PPC) during a vibrotactile TOJ task...... with stimuli applied to the right and left index fingers. In the first experiment, participants held their hands in an uncrossed configuration, and we found that when the index finger contralateral to the site of TMS was stimulated first, there was a significant increase in TOJ errors. This increase did...... that these TMS-induced changes in TOJ errors were not due to a reduced ability to detect the timing of the vibrotactile stimuli. Taken together, these results demonstrate that both the right and left PPC contribute to the processing underlying vibrotactile TOJs by integrating vibrotactile information...

  11. A miniature vibrotactile sensory substitution device for multifingered hand prosthetics.

    Science.gov (United States)

    Cipriani, Christian; D'Alonzo, Marco; Carrozza, Maria Chiara

    2012-02-01

    A multisite, vibrotactile sensory substitution system, that could be used in conjunction with artificial touch sensors in multifingered prostheses, to deliver sensory feedback to upper limb amputees is presented. The system is based on a low cost/power/size smart architecture of off-the-shelf miniaturized vibration motors; the main novelty is that it is able to generate stimuli where both vibration amplitude and frequency as well as beat interference can be modulated. This paper is aimed at evaluating this system by investigating the capability of healthy volunteers to perceive-on their forearms-vibrations with different amplitudes and/or frequencies. In addition, the ability of subjects in spatially discriminating stimulations on three forearm sites and recognizing six different combinations of stimulations was also addressed. Results demonstrate that subjects were able to discriminate different force amplitudes exerted by the device (accuracies greater than 75%); when both amplitude and frequency were simultaneously varied, the pure discrimination of amplitude/frequency variation was affected by the variation of the other. Subjects were also able to discriminate with an accuracy of 93% three different sites and with an accuracy of 78% six different stimulation patterns. © 2011 IEEE

  12. Activation of lateral hypothalamus-projecting parabrachial neurons by intraorally delivered gustatory stimuli

    Directory of Open Access Journals (Sweden)

    Kenichi eTokita

    2014-07-01

    Full Text Available The present study investigated a subpopulation of neurons in the mouse parabrachial nucleus (PbN, a gustatory and visceral relay area in the brainstem, that project to the lateral hypothalamus (LH. We made injections of the retrograde tracer Fluorogold (FG into LH, resulting in fluorescent labeling of neurons located in different regions of the PbN. Mice were stimulated through an intraoral cannula with one of seven different taste stimuli, and PbN sections were processed for immunohistochemical detection of the immediate early gene c-Fos, which labels activated neurons. LH projection neurons were found in all PbN subnuclei, but in greater concentration in lateral subnuclei, including the dorsal lateral subnucleus (dl. Fos-like immunoreactivity (FLI was observed in the PbN in a stimulus-dependent pattern, with the greatest differentiation between intraoral stimulation with sweet (0.5 M sucrose and bitter (0.003 M quinine compounds. In particular, sweet and umami-tasting stimuli evoked robust FLI in cells in the dl, whereas quinine evoked almost no FLI in cells in this subnucleus. Double-labeled cells were also found in the greatest quantity in the dl. Overall, these results support the hypothesis that the dl contains direct a projection to the LH that is activated preferentially by appetitive compounds; this projection may be mediated by taste and/or postingestive mechanisms.

  13. Vibrotactile Stimulation as an Instructor for Mimicry-Based Physical Exercise

    Directory of Open Access Journals (Sweden)

    Jani Lylykangas

    2015-01-01

    Full Text Available The present aim was to investigate functionality of vibrotactile stimulation in mimicry-based behavioral regulation during physical exercise. Vibrotactile stimuli communicated instructions from an instructor to an exerciser to perform lower extremity movements. A wireless prototype was tested first in controlled laboratory conditions (Study 1 and was followed by a user study (Study 2 that was conducted in a group exercise situation for elderly participants with a new version of the system with improved construction and extended functionality. The results of Study 1 showed that vibrotactile instructions were successful in both supplementing and substituting visual knee lift instructions. Vibrotactile stimuli were accurately recognized, and exercise with the device received affirmative ratings. Interestingly, tactile stimulation appeared to stabilize acceleration magnitude of the knee lifts in comparison to visual instructions. In Study 2 it was found that user experience of the system was mainly positive by both the exercisers and their instructors. For example, exercise with vibrotactile instructions was experienced as more motivating than conventional exercise session. Together the results indicate that tactile instructions could increase possibilities for people having difficulties in following visual and auditory instructions to take part in mimicry-based group training. Both studies also revealed development areas that were primarily related to a slight delay in triggering the vibrotactile stimulation.

  14. Vibrotactile Discrimination of Musical Timbre

    Science.gov (United States)

    Russo, Frank A.; Ammirante, Paolo; Fels, Deborah I.

    2012-01-01

    Five experiments investigated the ability to discriminate between musical timbres based on vibrotactile stimulation alone. Participants made same/different judgments on pairs of complex waveforms presented sequentially to the back through voice coils embedded in a conforming chair. Discrimination between cello, piano, and trombone tones matched…

  15. Design of a Vibrotactile Vest for Contour Perception

    Directory of Open Access Journals (Sweden)

    Juan Wu

    2012-11-01

    Full Text Available A vibrotactile array is a promising human computer interface which could display graphical information to users in a tactile form. This paper presents the design and testing of an image contour display system with a vibrotactile array. The tactile image display system is attached to the back of the user. It converts visual graphics into 2D tactile images and allows subjects to feel the contours of objects through vibration stimulus. The system consists of a USB camera, 48 (6×8 vibrating motors and an embedded control system. The image is captured by the camera and the 2D contour is extracted and transformed into vibrotactile stimuli using a temporal-spatial dynamic coding method. Preliminary experiments were carried out and the optimal parameters of the vibrating time and duration were explored. To evaluate the feasibility and robustness of this vibration mode, letters were also tactilely displayed and the recognition rate about the alphabet letter display was investigated. It was shown that under the condition of no pre-training for the subjects, the recognition rate was 82%. Such a recognition rate is higher than that of the scanning mode (47.5% and the improved handwriting mode (76.8%. The results indicated that the proposed method was efficient in conveying the contour information to the visually impaired by means of vibrations.

  16. Plantar vibrotactile detection deficits in adults with chronic ankle instability.

    Science.gov (United States)

    Hoch, Matthew C; McKeon, Patrick O; Andreatta, Richard D

    2012-04-01

    The purpose of this study was to investigate the vibrotactile detection thresholds of the plantar cutaneous afferents in subjects with chronic ankle instability compared with healthy control subjects. Eight adults with chronic ankle instability and eight adults with no ankle sprain history participated. Vibrotactile detection thresholds were assessed using a mechanical stimulus generator system, mounted onto an articulated microscope arm, which delivered sinusoidal vibrotactile inputs to the foot sole at three different sites: head of the first metatarsal, base of the fifth metatarsal, and the heel. Vibrotactile stimulation was delivered at a range of test frequencies that corresponded to the known responsiveness of cutaneous mechanoreceptors in the glabrous skin of the foot sole (10, 25, and 50 Hz). Probe displacement measures (dB) from the last eight displacement trials that contained 50% positive detection responses were averaged to obtain a single threshold estimate for each test frequency and site combination. The results of this study indicate that no significant group-by-site interactions were found for any test frequencies (P > 0.29). However, group main effects were present at the 10-Hz (P < 0.0001), 25-Hz (P = 0.03), and 50-Hz (P = 0.04) test frequencies, indicating that subjects with chronic ankle instability had significantly higher detection thresholds or less sensitivity when stimulation sites were pooled. The results of this study indicate that subjects with chronic ankle instability may demonstrate decreased sensitivity on the plantar surface of the foot. These alterations in plantar cutaneous somatosensation may help explain the underlying mechanisms associated with the prolonged sensorimotor system impairments in postural control and gait commonly exhibited by people with chronic ankle instability.

  17. Vibrotactile Vest and The Humming Wall

    DEFF Research Database (Denmark)

    Morrison, Ann; Manresa-Yee, Cristina; Knoche, Hendrik

    2015-01-01

    Vibrotactile information can be used to elicit sensations and encourage particular user body movements. We designed a vibrotactile vest with physiological monitoring that interacts with a vibroacoustic urban environment, The Humming Wall. In this paper, we describe the first field trial with the ......, with a system designed to calm, activate, guide and warn the participants....

  18. Toward Personalized Vibrotactile Support When Learning Motor Skills

    Directory of Open Access Journals (Sweden)

    Olga C. Santos

    2017-01-01

    Full Text Available Personal tracking technologies allow sensing of the physical activity carried out by people. Data flows collected with these sensors are calling for big data techniques to support data collection, integration and analysis, aimed to provide personalized support when learning motor skills through varied multisensorial feedback. In particular, this paper focuses on vibrotactile feedback as it can take advantage of the haptic sense when supporting the physical interaction to be learnt. Despite each user having different needs, when providing this vibrotactile support, personalization issues are hardly taken into account, but the same response is delivered to each and every user of the system. The challenge here is how to design vibrotactile user interfaces for adaptive learning of motor skills. TORMES methodology is proposed to facilitate the elicitation of this personalized support. The resulting systems are expected to dynamically adapt to each individual user’s needs by monitoring, comparing and, when appropriate, correcting in a personalized way how the user should move when practicing a predefined movement, for instance, when performing a sport technique or playing a musical instrument.

  19. Design of Dynamic Vibrotactile Textures.

    Science.gov (United States)

    Ahmaniemi, Teemu; Marila, Juha; Lantz, Vuokko

    2010-01-01

    This paper describes a method for creating virtual textures without force feedback by using a simple motion sensor and a single vibrotactile actuator. It is based on wavetable synthesis driven by the user's hand movements. The output of the synthesis is rendered with the tactile actuator attached in a hand-held box together with the motion sensor. The method provides a solution for creating tangible properties for virtual objects which can be explored by pointing at them with the sensor-actuator device. The study introduces 12 virtual textures which were based on three different envelope ridge lengths, two spatial densities, and were either regularly or irregularly organized. To evaluate the role of each design parameter in the perception of the texture, a series of experiments was conducted. The perceived similarity was assessed in a pairwise comparison test and the outcome was analyzed by using multidimensional scaling. The analysis revealed that envelope ridge length and spatial density were distinguishable design parameters while regularity was not. The textures were also rated according to five attribute scales previously determined in the pilot experiment. The results show that ridge length and spatial density influence perceived roughness and flatness similarly as with real textures.

  20. Psychophysical correspondence between vibrotactile intensity and intracortical microstimulation for tactile neuroprostheses in rats

    Science.gov (United States)

    Devecioğlu, İsmail; Güçlü, Burak

    2017-02-01

    Objective. Recent studies showed that intracortical microstimulation (ICMS) generates artificial sensations which can be utilized as somatosensory feedback in cortical neuroprostheses. To mimic the natural psychophysical response, ICMS parameters are modulated according to psychometric equivalence functions (PEFs). PEFs match the intensity levels of ICMS and mechanical stimuli, which elicit equal detection probabilities, but they typically do not include the frequency as a control variable. We aimed to establish frequency-dependent PEFs for vibrotactile stimulation of the glabrous skin and ICMS in the primary somatosensory cortex of awake freely behaving rats. Approach. We collected psychometric data for vibrotactile and ICMS detection at three stimulation frequencies (40, 60 and 80 Hz). The psychometric data were fitted with a model equation of two independent variables (stimulus intensity and frequency) and four subject-dependent parameters. For each rat, we constructed a separate PEF which was used to estimate the ICMS current amplitude for a given displacement amplitude and frequency. The ICMS frequency was set equal to the vibrotactile frequency. We validated the PEFs in a modified task which included randomly selected probe trials presented either with a vibrotactile or an ICMS stimulus, and also at frequencies and intensity levels not tested before. Main results. The PEFs were generally successful in estimating the ICMS current intensities (no significant differences between vibrotactile and ICMS trials in Kolmogorov-Smirnov tests). Specifically, hit rates from both trial conditions were significantly correlated in 86% of the cases, and 52% of all data had perfect match in linear regression. Significance. The psychometric correspondence model presented in this study was constructed based on surface functions which define psychophysical detection probability as a function of stimulus intensity and frequency. Therefore, it may be used for the real

  1. Vibro-Tactile Information Presentation in Automobiles

    NARCIS (Netherlands)

    Erp, J.B.F. van; Veen, H.A.H.C. van

    2001-01-01

    This paper describes the potential of using vibro-tactile displays for automobile drivers. Technological developments in the field of driver support systems and tactile displays, combined with the ever increasing need to enlarge the capacity of the driver's information channel, farm the reason to

  2. Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers.

    Science.gov (United States)

    Bhattacharjee, Arindam; Ye, Amanda J; Lisak, Joy A; Vargas, Maria G; Goldreich, Daniel

    2010-10-27

    Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at ∼100 ms intervals, and adjacent raised dots within a character at 50 ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25 ms target tap) and amplitude discrimination (compared with 100 μm reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker, 50 Hz, 50 μm; target-masker delays, ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged but that perceptual processing is accelerated in congenitally blind Braille readers.

  3. Spectral EEG abnormalities during vibrotactile encoding and quantitative working memory processing in schizophrenia

    Directory of Open Access Journals (Sweden)

    Simon Ludwig

    2016-01-01

    Full Text Available Schizophrenia is associated with a number of cognitive impairments such as deficient sensory encoding or working memory processing. However, it is largely unclear how dysfunctions on these various levels of cortical processing contribute to alterations of stimulus-specific information representation. To test this, we used a well-established sequential frequency comparison paradigm, in which sensory encoding of vibrotactile stimuli can be assessed via frequency-specific steady-state evoked potentials (SSEPs over primary somatosensory cortex (S1. Further, we investigated the maintenance of frequency information in working memory (WM in terms of parametric power modulations of induced beta-band EEG oscillations. In the present study schizophrenic patients showed significantly less pronounced SSEPs during vibrotactile stimulation than healthy controls. In particular, inter-trial phase coherence was reduced. While maintaining vibrotactile frequencies in WM, patients showed a significantly weaker prefrontal beta-power modulation compared to healthy controls. Crucially, patients exhibited no general disturbances in attention, as inferred from a behavioral test and from alpha-band event-related synchronization. Together, our results provide novel evidence that patients with schizophrenia show altered neural correlates of stimulus-specific sensory encoding and WM maintenance, suggesting an early somatosensory impairment as well as alterations in the formation of abstract representations of task-relevant stimulus information.

  4. Spike Timing Matters in Novel Neuronal Code Involved in Vibrotactile Frequency Perception.

    Science.gov (United States)

    Birznieks, Ingvars; Vickery, Richard M

    2017-05-22

    Skin vibrations sensed by tactile receptors contribute significantly to the perception of object properties during tactile exploration [1-4] and to sensorimotor control during object manipulation [5]. Sustained low-frequency skin vibration (perception of frequency is still unknown. Measures based on mean spike rates of neurons in the primary somatosensory cortex are sufficient to explain performance in some frequency discrimination tasks [7-11]; however, there is emerging evidence that stimuli can be distinguished based also on temporal features of neural activity [12, 13]. Our study's advance is to demonstrate that temporal features are fundamental for vibrotactile frequency perception. Pulsatile mechanical stimuli were used to elicit specified temporal spike train patterns in tactile afferents, and subsequently psychophysical methods were employed to characterize human frequency perception. Remarkably, the most salient temporal feature determining vibrotactile frequency was not the underlying periodicity but, rather, the duration of the silent gap between successive bursts of neural activity. This burst gap code for frequency represents a previously unknown form of neural coding in the tactile sensory system, which parallels auditory pitch perception mechanisms based on purely temporal information where longer inter-pulse intervals receive higher perceptual weights than short intervals [14]. Our study also demonstrates that human perception of stimuli can be determined exclusively by temporal features of spike trains independent of the mean spike rate and without contribution from population response factors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Repeated training with augmentative vibrotactile feedback increases object manipulation performance.

    Directory of Open Access Journals (Sweden)

    Cara E Stepp

    Full Text Available Most users of prosthetic hands must rely on visual feedback alone, which requires visual attention and cognitive resources. Providing haptic feedback of variables relevant to manipulation, such as contact force, may thus improve the usability of prosthetic hands for tasks of daily living. Vibrotactile stimulation was explored as a feedback modality in ten unimpaired participants across eight sessions in a two-week period. Participants used their right index finger to perform a virtual object manipulation task with both visual and augmentative vibrotactile feedback related to force. Through repeated training, participants were able to learn to use the vibrotactile feedback to significantly improve object manipulation. Removal of vibrotactile feedback in session 8 significantly reduced task performance. These results suggest that vibrotactile feedback paired with training may enhance the manipulation ability of prosthetic hand users without the need for more invasive strategies.

  6. A Physics-Based Vibrotactile Feedback Library for Collision Events.

    Science.gov (United States)

    Park, Gunhyuk; Choi, Seungmoon

    2017-01-01

    We present PhysVib: a software solution on the mobile platform extending an open-source physics engine in a multi-rate rendering architecture for automatic vibrotactile feedback upon collision events. PhysVib runs concurrently with a physics engine at a low update rate and generates vibrotactile feedback commands at a high update rate based on the simulation results of the physics engine using an exponentially-decaying sinusoidal model. We demonstrate through a user study that this vibration model is more appropriate to our purpose in terms of perceptual quality than more complex models based on sound synthesis. We also evaluated the perceptual performance of PhysVib by comparing eight vibrotactile rendering methods. Experimental results suggested that PhysVib enables more realistic vibrotactile feedback than the other methods as to perceived similarity to the visual events. PhysVib is an effective solution for providing physically plausible vibrotactile responses while reducing application development time to great extent.

  7. Vibrotactile perception assessment for a haptic interface on an antigravity suit.

    Science.gov (United States)

    Ko, Sang Min; Lee, Kwangil; Kim, Daeho; Ji, Yong Gu

    2017-01-01

    Haptic technology is used in various fields to transmit information to the user with or without visual and auditory cues. This study aimed to provide preliminary data for use in developing a haptic interface for an antigravity (anti-G) suit. With the structural characteristics of the anti-G suit in mind, we determined five areas on the body (lower back, outer thighs, inner thighs, outer calves, and inner calves) on which to install ten bar-type eccentric rotating mass (ERM) motors as vibration actuators. To determine the design factors of the haptic anti-G suit, we conducted three experiments to find the absolute threshold, moderate intensity, and subjective assessments of vibrotactile stimuli. Twenty-six fighter pilots participated in the experiments, which were conducted in a fixed-based flight simulator. From the results of our study, we recommend 1) absolute thresholds of ∼11.98-15.84 Hz and 102.01-104.06 dB, 2) moderate intensities of 74.36 Hz and 126.98 dB for the lower back and 58.65 Hz and 122.37 dB for either side of the thighs and calves, and 3) subjective assessments of vibrotactile stimuli (displeasure, easy to perceive, and level of comfort). The results of this study will be useful for the design of a haptic anti-G suit. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

    Science.gov (United States)

    Goltz, Dominique; Pleger, Burkhard; Thiel, Sabrina; Villringer, Arno; Müller, Matthias M.

    2013-01-01

    The present functional magnetic resonance imaging (fMRI) study was designed to get a better understanding of the brain regions involved in sustained spatial attention to tactile events and to ascertain to what extent their activation was correlated. We presented continuous 20 Hz vibrotactile stimuli (range of flutter) concurrently to the left and right index fingers of healthy human volunteers. An arrow cue instructed subjects in a trial-by-trial fashion to attend to the left or right index finger and to detect rare target events that were embedded in the vibrotactile stimulation streams. We found blood oxygen level-dependent (BOLD) attentional modulation in primary somatosensory cortex (SI), mainly covering Brodmann area 1, 2, and 3b, as well as in secondary somatosensory cortex (SII), contralateral to the to-be-attended hand. Furthermore, attention to the right (dominant) hand resulted in additional BOLD modulation in left posterior insula. All of the effects were caused by an increased activation when attention was paid to the contralateral hand, except for the effects in left SI and insula. In left SI, the effect was related to a mixture of both a slight increase in activation when attention was paid to the contralateral hand as well as a slight decrease in activation when attention was paid to the ipsilateral hand (i.e., the tactile distraction condition). In contrast, the effect in left posterior insula was exclusively driven by a relative decrease in activation in the tactile distraction condition, which points to an active inhibition when tactile information is irrelevant. Finally, correlation analyses indicate a linear relationship between attention effects in intrahemispheric somatosensory cortices, since attentional modulation in SI and SII were interrelated within one hemisphere but not across hemispheres. All in all, our results provide a basis for future research on sustained attention to continuous vibrotactile stimulation in the range of flutter

  9. Vibrotactile sensory substitution elicits feeling of ownership of an alien hand.

    Directory of Open Access Journals (Sweden)

    Marco D'Alonzo

    Full Text Available Tactile feedback plays a key role in the attribution of a limb to the self and in the motor control of grasping and manipulation. However, due to technological limits, current prosthetic hands do not provide amputees with cutaneous touch feedback. Recent findings showed that amputees can be tricked into experiencing an alien rubber hand as part of their own body, by applying synchronous touches to the stump which is out of view, and to the rubber hand in full view. It was suggested that similar effects could be achieved by using a prosthesis with touch sensors that provides synchronous cutaneous feedback through an array of tactile stimulators on the stump. Such a prosthesis holds the potential to be easily incorporated within one's body scheme, because it would reproduce the perceptual illusion in everyday usage. We propose to use sensory substitution--specifically vibrotactile--to address this issue, as current haptic technology is still too bulky and inefficient. In this basic study we addressed the fundamental question of whether visuo-tactile modality mismatch promotes self-attribution of a limb, and to what extent compared to a modality-matched paradigm, on normally-limbed subjects. We manipulated visuo-tactile stimulations, comprising combinations of modality matched, modality mismatched, synchronous and asynchronous stimulations, in a set of experiments fashioned after the Rubber Hand Illusion. Modality mismatched stimulation was provided using a keypad-controlled vibrotactile display. Results from three independent measures of embodiment (questionnaires, pointing tests and skin conductance responses indicate that vibrotactile sensory substitution can be used to induce self-attribution of a rubber hand when synchronous but modality-conflicting visuo-tactile stimulation is delivered to the biological finger pads and to the equivalent rubber hand phalanges.

  10. Inherent problems of attempts to apply sonar and vibrotactile sensory aid technology to the perceptual needs of the blind.

    Science.gov (United States)

    Easton, R D

    1992-01-01

    A program of research dealing with two types of sensory aids for the blind--sonar and vibrotactile--is described. Rather than immediately assessing the aids in the mobility context, which has customarily been the case, the aids' capabilities are considered in terms of the major functions of vision, that is, the exteroceptive perception of objects, surfaces, and events of the environment, and the proprioceptive perception of the self, especially the self in relation to the environment. Although sonar aids function very well for localizing objects and for providing acoustic flow specifying self-movement, they do not provide high acuity pattern and shape information due to the long wavelength of ultrasound relative to light. This limitation is considered specifically with respect to the visual accomplishment of recovery of three-dimensional structure/motion from dynamic two-dimensional images. Vibrotactile sensory aids using optical imaging can deliver detailed pattern information to the skin and thus permit assessment of the extent to which a nonvisual system can mediate the recovery of structure problem. However, in even moderately cluttered or complicated environments the skin proves unable to resolve the amount of stimulation it receives vibrotactually. The limitations of sonar and vibrotactile sensory aids are discussed with respect to future sensory substitution efforts as well as their implications for understanding differences and similarities among the senses.

  11. Effects of Vibrotactile Feedback on Human Learning of Arm Motions

    Science.gov (United States)

    Bark, Karlin; Hyman, Emily; Tan, Frank; Cha, Elizabeth; Jax, Steven A.; Buxbaum, Laurel J.; Kuchenbecker, Katherine J.

    2015-01-01

    Tactile cues generated from lightweight, wearable actuators can help users learn new motions by providing immediate feedback on when and how to correct their movements. We present a vibrotactile motion guidance system that measures arm motions and provides vibration feedback when the user deviates from a desired trajectory. A study was conducted to test the effects of vibrotactile guidance on a subject’s ability to learn arm motions. Twenty-six subjects learned motions of varying difficulty with both visual (V), and visual and vibrotactile (VVT) feedback over the course of four days of training. After four days of rest, subjects returned to perform the motions from memory with no feedback. We found that augmenting visual feedback with vibrotactile feedback helped subjects reduce the root mean square (rms) angle error of their limb significantly while they were learning the motions, particularly for 1DOF motions. Analysis of the retention data showed no significant difference in rms angle errors between feedback conditions. PMID:25486644

  12. Facial Vibrotactile Stimulation Activates the Parasympathetic Nervous System: Study of Salivary Secretion, Heart Rate, Pupillary Reflex, and Functional Near-Infrared Spectroscopy Activity

    Directory of Open Access Journals (Sweden)

    Hisao Hiraba

    2014-01-01

    Full Text Available We previously found that the greatest salivation response in healthy human subjects is produced by facial vibrotactile stimulation of 89 Hz frequency with 1.9 μm amplitude (89 Hz-S, as reported by Hiraba et al. (2012, 20011, and 2008. We assessed relationships between the blood flow to brain via functional near-infrared spectroscopy (fNIRS in the frontal cortex and autonomic parameters. We used the heart rate (HRV: heart rate variability analysis in RR intervals, pupil reflex, and salivation as parameters, but the interrelation between each parameter and fNIRS measures remains unknown. We were to investigate the relationship in response to established paradigms using simultaneously each parameter-fNIRS recording in healthy human subjects. Analysis of fNIRS was examined by a comparison of various values between before and after various stimuli (89 Hz-S, 114 Hz-S, listen to classic music, and “Ahh” vocalization. We confirmed that vibrotactile stimulation (89 Hz of the parotid glands led to the greatest salivation, greatest increase in heart rate variability, and the most constricted pupils. Furthermore, there were almost no detectable differences between fNIRS during 89 Hz-S and fNIRS during listening to classical music of fans. Thus, vibrotactile stimulation of 89 Hz seems to evoke parasympathetic activity.

  13. Toward Personalized Vibrotactile Support When Learning Motor Skills

    OpenAIRE

    Olga C. Santos

    2017-01-01

    Personal tracking technologies allow sensing of the physical activity carried out by people. Data flows collected with these sensors are calling for big data techniques to support data collection, integration and analysis, aimed to provide personalized support when learning motor skills through varied multisensorial feedback. In particular, this paper focuses on vibrotactile feedback as it can take advantage of the haptic sense when supporting the physical interaction to be learnt. Despite ea...

  14. Influence of Vibrotactile Feedback on Controlling Tilt Motion After Spaceflight

    Science.gov (United States)

    Wood, S. J.; Rupert, A. H.; Vanya, R. D.; Esteves, J. T.; Clement, G.

    2011-01-01

    We hypothesize that adaptive changes in how inertial cues from the vestibular system are integrated with other sensory information leads to perceptual disturbances and impaired manual control following transitions between gravity environments. The primary goals of this ongoing post-flight investigation are to quantify decrements in manual control of tilt motion following short-duration spaceflight and to evaluate vibrotactile feedback of tilt as a sensorimotor countermeasure. METHODS. Data is currently being collected on 9 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s, 30% based on the gain or the amount of tilt disturbance successfully nulled. Manual control performance tended to return to baseline levels within 1-2 days following landing. Root-mean-square position error and tilt velocity were significantly reduced with vibrotactile feedback. CONCLUSIONS. These preliminary results are consistent with our hypothesis that adaptive changes in vestibular processing corresponds to reduced manual control performance following G-transitions. A simple vibrotactile prosthesis improves the ability to null out tilt motion within a limited range of motion disturbances.

  15. Wearable Vibrotactile Haptic Device for Stiffness Discrimination during Virtual Interactions

    Directory of Open Access Journals (Sweden)

    Andualem Tadesse Maereg

    2017-09-01

    Full Text Available In this paper, we discuss the development of cost effective, wireless, and wearable vibrotactile haptic device for stiffness perception during an interaction with virtual objects. Our experimental setup consists of haptic device with five vibrotactile actuators, virtual reality environment tailored in Unity 3D integrating the Oculus Rift Head Mounted Display (HMD and the Leap Motion controller. The virtual environment is able to capture touch inputs from users. Interaction forces are then rendered at 500 Hz and fed back to the wearable setup stimulating fingertips with ERM vibrotactile actuators. Amplitude and frequency of vibrations are modulated proportionally to the interaction force to simulate the stiffness of a virtual object. A quantitative and qualitative study is done to compare the discrimination of stiffness on virtual linear spring in three sensory modalities: visual only feedback, tactile only feedback, and their combination. A common psychophysics method called the Two Alternative Forced Choice (2AFC approach is used for quantitative analysis using Just Noticeable Difference (JND and Weber Fractions (WF. According to the psychometric experiment result, average Weber fraction values of 0.39 for visual only feedback was improved to 0.25 by adding the tactile feedback.

  16. 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

  17. Comparing spatially static and dynamic vibrotactile take-over requests in the driver seat.

    Science.gov (United States)

    Petermeijer, S M; Cieler, S; de Winter, J C F

    2017-02-01

    Vibrotactile stimuli can be effective as warning signals, but their effectiveness as directional take-over requests in automated driving is yet unknown. This study aimed to investigate the correct response rate, reaction times, and eye and head orientation for static versus dynamic directional take-over requests presented via vibrating motors in the driver seat. In a driving simulator, eighteen participants performed three sessions: 1) a session involving no driving (Baseline), 2) driving a highly automated car without additional task (HAD), and 3) driving a highly automated car while performing a mentally demanding task (N-Back). Per session, participants received four directional static (in the left or right part of the seat) and four dynamic (moving from one side towards the opposite left or right of the seat) take-over requests via two 6×4 motor matrices embedded in the seat back and bottom. In the Baseline condition, participants reported whether the cue was left or right, and in the HAD and N-Back conditions participants had to change lanes to the left or to the right according to the directional cue. The correct response rate was operationalized as the accuracy of the self-reported direction (Baseline session) and the accuracy of the lane change direction (HAD & N-Back sessions). The results showed that the correct response rate ranged between 94% for static patterns in the Baseline session and 74% for dynamic patterns in the N-Back session, although these effects were not statistically significant. Steering wheel touch and steering input reaction times were approximately 200ms faster for static patterns than for dynamic ones. Eye tracking results revealed a correspondence between head/eye-gaze direction and lane change direction, and showed that head and eye-gaze movements where initiated faster for static vibrations than for dynamic ones. In conclusion, vibrotactile stimuli presented via the driver seat are effective as warnings, but their effectiveness

  18. Guidelines for the use of vibro-tactile displays in human computer interaction

    NARCIS (Netherlands)

    Erp, J.B.F. van

    2002-01-01

    Vibro-tactile displays convey messages by presenting vibration to the user's skin. In recent years, the interest in and application of vibro-tactile displays is growing. Vibratory displays are introduced in mobile devices, desktop applications and even in aircraft [1]. Despite the growing interest,

  19. The Hedonic Haptics Player: A Wearable Device to Experience Vibrotactile Compositions

    DEFF Research Database (Denmark)

    Boer, Laurens; Vallgårda, Anna; Cahill, Ben

    2017-01-01

    The Hedonic Haptics player is a portable wearable device that plays back vibrotactile compositions. It consists of three domes each of which houses a vibration motor providing vibrotactile sensations to the wearer. The domes are connected to a control unit the size of a small Walkman. The Hedonic...

  20. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Directory of Open Access Journals (Sweden)

    Carl Hopkins

    Full Text Available Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  1. Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception.

    Science.gov (United States)

    Hopkins, Carl; Maté-Cid, Saúl; Fulford, Robert; Seiffert, Gary; Ginsborg, Jane

    2016-01-01

    Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception.

  2. Designing a Vibrotactile Language for a Wearable Vest

    DEFF Research Database (Denmark)

    Morrison, Ann; Knoche, Hendrik; Manresa-Yee, Cristina

    2015-01-01

    We designed a wearable vest that houses a set of actuators to be placed at specific points on the body. We developed vibrotactile patterns to induce five sensation types: (1) Calming, (2 patterns, Up and Down back) (2) Feel Good (4 patterns in different directions around the waist), (3) Activating...... (2 patterns, Tarzan and Shiver, on top front of body and then down the back as well for Shiver), (4) Navigation (2 patterns, Turn Left and Turn Right, prompting on back then opposite side front waist) for full body turning and (5) Warning, (1 pattern on solar plexus) to slow down or stop the wearers...

  3. Interactive Furniture: Bi-directional Interaction with a Vibrotactile Wearable Sensate Vest in an Urban Space

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Leegaard, Jack Højholt; Manresa, Cristina

    2017-01-01

    In this study we investigate the experience for participants while wearing a vi-brotactile vest that interacts with a vibroacoustic architecture The Humming Wall, set in an urban space. This public large scale artefact is built to exchange vibrotactile and physiological interactions with a vibrot......In this study we investigate the experience for participants while wearing a vi-brotactile vest that interacts with a vibroacoustic architecture The Humming Wall, set in an urban space. This public large scale artefact is built to exchange vibrotactile and physiological interactions...... with a vibrotactile wearable vest. The heart beats and breath rates of the vest wearers are vibroacoustically displayed at The Humming Wall. In addition, participants can swipe and knock on The Hum-ming Wall and the vest wearer is effectively swiped and knocked upon. We work with overlapping vibrotactile outputs...... in order that the wearers experience a flow of sensations similar to a touch gesture. The communication privileged vi-broacoustic and vibrotactile as the primary interaction modalities for both vest wearers as well as for a passing public. The participants found the experience fa-vourable and analysis...

  4. Investigating the role of vibrotactile noise in early response to perturbation.

    Science.gov (United States)

    Hur, Pilwon; Wan, Yao-Hung; Seo, Na Jin

    2014-06-01

    Timely reaction to perturbation is important in activities of daily living. Modulation of reaction time to and early recovery from perturbation via vibrotactile noise was investigated. It was hypothesized that subthreshold vibrotactile noise applied to the upper extremity can accelerate a person's reaction to and recovery from handle perturbation. This intervention was developed based on previous studies in which the earliest cue available for people to detect handle perturbation was somatosensation detecting changes in pressure on the hand whose sensitivity can improve with subthreshold vibrotactile noise. To induce a handle perturbation, a sudden upward load was applied to the handle that subjects were lightly grasping. Eighteen healthy subjects were instructed to stop the handle from moving up when they detected the perturbation. The muscle reaction time and handle stabilization time with and without vibrotactile noise were determined. The results showed that the muscle reaction time and handle stabilization time significantly decreased by 3 ms ( ) and 6 ms ( ), respectively, when vibrotactile noise was applied to the upper extremity, regardless of where the noise was applied among four different locations within the upper extremity ( p > 0.05). In conclusion, the application of subthreshold vibrotactile noise enhanced persons' muscle reaction time to handle perturbation and led to early recovery from the perturbation. Use of the vibrotactile noise may increase a person's ability to rapidly respond to perturbation of a grasped object in potentially dangerous situations such as holding onto ladder rungs from elevation or manipulating knives.

  5. Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

    Science.gov (United States)

    Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

    2013-01-01

    Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

  6. Evaluation of pitch coding alternatives for vibrotactile stimulation in speech training of the deaf

    Energy Technology Data Exchange (ETDEWEB)

    Barbacena, I L; Barros, A T [CEFET/PB, Joao Pessoa - PB (Brazil); Freire, R C S [DEE, UFCG, Campina Grande-PB (Brazil); Vieira, E C A [CEFET/PB, Joao Pessoa - PB (Brazil)

    2007-11-15

    Use of vibrotactile feedback stimulation as an aid for speech vocalization by the hearing impaired or deaf is reviewed. Architecture of a vibrotactile based speech therapy system is proposed. Different formulations for encoding the fundamental frequency of the vocalized speech into the pulsed stimulation frequency are proposed and investigated. Simulation results are also presented to obtain a comparative evaluation of the effectiveness of the different formulated transformations. Results of the perception sensitivity to the vibrotactile stimulus frequency to verify effectiveness of the above transformations are included.

  7. Soft pneumatic actuator skin with piezoelectric sensors for vibrotactile feedback

    Directory of Open Access Journals (Sweden)

    Harshal Arun Sonar

    2016-01-01

    Full Text Available The latest wearable technologies demand more intuitive and sophisticated interfaces for communication, sensing, and feedback closer to the body. Evidently, such interfaces require flexibility and conformity without losing their functionality even on rigid surfaces. Although there has been various research efforts in creating tactile feedback to improve various haptic interfaces and master-slave manipulators, we are yet to see a comprehensive device that can both supply vibratory actuation and tactile sensing. This paper describes a soft pneumatic actuator (SPA based, SPA-skin prototype that allows bidirectional tactile information transfer to facilitate simpler and responsive wearable interface. We describe the design and fabrication of a 1.4 mm-thick vibratory SPA - skin that is integrated with piezoelectric sensors. We examine in detail the mechanical performance compared to the SPA model and the sensitivity of the sensors for the application in vibrotactile feedback. Experimental findings show that this ultra-thin SPA and the unique integration process of the discrete lead zirconate titanate (PZT based piezoelectric sensors achieve high resolution of soft contact sensing as well as accurate control on vibrotactile feedback by closing the control loop.

  8. Effects of vibrotactile vestibular substitution on vestibular rehabilitation - preliminary study,

    Directory of Open Access Journals (Sweden)

    Cibele Brugnera

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: Some patients with severe impairment of body balance do not obtain adequate improvement from vestibular rehabilitation (VR. OBJECTIVE: To evaluate the effectiveness of Vertiguard(tm biofeedback equipment as a sensory substitution (SS of the vestibular system in patients who did not obtain sufficient improvement from VR. METHODS: This was a randomized prospective clinical study. Thirteen patients without satisfactory response to conventional VR were randomized into a study group (SG, which received the vibrotactile stimulus from Vertiguard(tm for ten days, and a control group (CG, which used equipment without the stimulus. For pre- and post-treatment assessment, the Sensory Organization Test (SOT protocol of the Computerized Dynamic Posturography (CDP and two scales of balance self-perception, Activities-specific Balance Confidence (ABC and Dizziness Handicap Inventory (DHI, were used. RESULTS: After treatment, only the SG showed statistically significant improvement in C5 (p = 0.007 and C6 (p = 0.01. On the ABC scale, there was a significant difference in the SG (p= 0.04. The DHI showed a significant difference in CG and SG with regard to the physical aspect, and only in the SG for the functional aspect (p = 0.04. CONCLUSION: The present findings show that sensory substitution using the vibrotactile stimulus of the Vertiguard(tm system helped with the integration of neural networks involved in maintaining posture, improving the strategies used in the recovery of body balance.

  9. Effects of vibrotactile vestibular substitution on vestibular rehabilitation - preliminary study.

    Science.gov (United States)

    Brugnera, Cibele; Bittar, Roseli Saraiva Moreira; Greters, Mário Edvin; Basta, Dietmar

    2015-01-01

    Some patients with severe impairment of body balance do not obtain adequate improvement from vestibular rehabilitation (VR). To evaluate the effectiveness of Vertiguard™ biofeedback equipment as a sensory substitution (SS) of the vestibular system in patients who did not obtain sufficient improvement from VR. This was a randomized prospective clinical study. Thirteen patients without satisfactory response to conventional VR were randomized into a study group (SG), which received the vibrotactile stimulus from Vertiguard™ for ten days, and a control group (CG), which used equipment without the stimulus. For pre- and post-treatment assessment, the Sensory Organization Test (SOT) protocol of the Computerized Dynamic Posturography (CDP) and two scales of balance self-perception, Activities-specific Balance Confidence (ABC) and Dizziness Handicap Inventory (DHI), were used. After treatment, only the SG showed statistically significant improvement in C5 (p=0.007) and C6 (p=0.01). On the ABC scale, there was a significant difference in the SG (p=0.04). The DHI showed a significant difference in CG and SG with regard to the physical aspect, and only in the SG for the functional aspect (p=0.04). The present findings show that sensory substitution using the vibrotactile stimulus of the Vertiguard™ system helped with the integration of neural networks involved in maintaining posture, improving the strategies used in the recovery of body balance. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  10. The Use of Vibrotactile Aids with Preschool Hearing-Impaired Children: Case Studies.

    Science.gov (United States)

    Sheehy, Patti; Hansen, Susan Aaberg

    1983-01-01

    Case studies of three hearing-impaired four-year-old children revealed that vibrotactile stimulation aids were effective in teaching speech skills. The aid helped the students become more aware of sounds. (CL)

  11. A Vibrotactile Interface to Motivate Movement for Children with Severe to Profound Disabilities

    DEFF Research Database (Denmark)

    Manresa-Yee, Cristina; Morrison, Ann; Larsen, Jeppe Veirum

    2014-01-01

    V-Sense is a vibrotactile interface that encourages children with severe or profound cognitive, sensory and physical impairments to move. The interface makes use of touch, in particular vibrations, as a supportive function to motivate users' actions. Specifically, we propose a vibrotactile...... interface on the arm and around the shoulder using the saltation perceptual illusion to induce movement of the corresponding joint. In this paper we describe the design principles of the interface and the proposed experimental design to evaluate it....

  12. The influence of prior experience and expected timing on vibrotactile discrimination

    Science.gov (United States)

    Karim, Muhsin; Harris, Justin A.; Langdon, Angela; Breakspear, Michael

    2013-01-01

    Vibrotactile discrimination tasks involve perceptual judgements on stimulus pairs separated by a brief interstimulus interval (ISI). Despite their apparent simplicity, decision making during these tasks is biased by prior experience in a manner that is not well understood. A striking example is when participants perform well on trials where the first stimulus is closer to the mean of the stimulus-set than the second stimulus, and perform comparatively poorly when the first stimulus is further from the stimulus mean. This “time-order effect” suggests that participants implicitly encode the mean of the stimulus-set and use this internal standard to bias decisions on any given trial. For relatively short ISIs, the magnitude of the time-order effect typically increases with the distance of the first stimulus from the global mean. Working from the premise that the time-order effect reflects the loss of precision in working memory representations, we predicted that the influence of the time-order effect, and this superimposed “distance” effect, would monotonically increase for trials with longer ISIs. However, by varying the ISI across four intervals (300, 600, 1200, and 2400 ms) we instead found a complex, non-linear dependence of the time-order effect on both the ISI and the distance, with the time-order effect being paradoxically stronger at short ISIs. We also found that this relationship depended strongly on participants' prior experience of the ISI (from previous task titration). The time-order effect not only depends on participants' expectations concerning the distribution of stimuli, but also on the expected timing of the trials. PMID:24399927

  13. The effect of condoms on penile vibrotactile sensitivity thresholds in young, heterosexual men

    Science.gov (United States)

    Hill, Brandon J.; Janssen, Erick; Kvam, Peter; Amick, Erick E.; Sanders, Stephanie A.

    2013-01-01

    Introduction Investigating the ways in which barrier methods such as condoms may affect penile sensory thresholds has potential relevance to the development of interventions in men who experience negative effects of condoms on sexual response and sensation. A quantitative, psychophysiological investigation examining the degree to which sensations are altered by condoms has, to date, not been conducted. Aim The objective of this study was to examine penile vibrotactile sensitivity thresholds in both flaccid and erect penises with and without a condom, while comparing men who do and those who do not report condom-associated erection problems (CAEP). Methods Penile vibrotactile sensitivity thresholds were assessed among a total of 141 young, heterosexual men using biothesiometry. An incremental two-step staircase method was used and repeated three times for each of four conditions. Intra-class correlation coefficients (ICC) were calculated for all vibratory assessments. Penile vibratory thresholds were compared using a mixed-model Analysis of Variance (ANOVA). Main Outcome Measures Penile vibrotactile sensitivity thresholds with and without a condom, erectile function measured by International Index of Erectile Function Questionnaire (IIEF), and self-reported degree of erection. Results Significant main effects of condoms (yes/no) and erection (yes/no) were found. No main or interaction effects of CAEP were found. Condoms were associated with higher penile vibrotactile sensitivity thresholds (F(1, 124)=17.11, pPenile vibrotactile thresholds were higher with an erect than with a flaccid penis (F(1, 124)=4.21, p=.042). Conclusion The current study demonstrates the feasibility of measuring penile vibratory thresholds with and without a condom in both erect and flaccid experimental conditions. As might be expected, condoms increased penile vibrotactile sensitivity thresholds. Interestingly, erections were associated with the highest thresholds. Thus, this study was the

  14. Effect of individual finger skin temperature on vibrotactile perception threshold

    Directory of Open Access Journals (Sweden)

    Barbara Harazin

    2013-12-01

    Full Text Available Objectives: In healthy people, the vibrotactile perception threshold (VPT at fingertips depends on a given measurement method and on individual characteristics such as age, gender and finger skin temperature. The aim of the study was to compare the VPT values in 2 groups of healthy subjects with different finger skin temperature. Materials and Methods: The study group comprised 56 males and 76 females, who formed pairs matched with respect to age, gender and body mass index (BMI but differing in terms of finger skin temperature at pre-launch testing. The finger skin temperature of less than 29°C indicated the subjects with "cold hands" and that of more than 29°C, the subjects with "warm hands". The measuring system made use of P8 pallesthesiometer (EMSON-MAT, Poland and the measurement procedure was in compliance with the ISO 13091-1:2001 standard. VPT measurements were performed for the index, middle and ring fingers of both hands at the frequencies of 4 Hz, 25 Hz, 31.5 Hz, 63 Hz, 125 Hz and 250 Hz. Results: The findings of the study revealed that the mean VPTs among the subjects with "cold hands" were significantly higher than the corresponding values among the subjects with "warm hands". Conclusions: The type of individual peripheral thermoregulation should be considered when assessing the VPT and determining its reference values.

  15. A brain-computer interface with vibrotactile biofeedback for haptic information

    Directory of Open Access Journals (Sweden)

    Acharya Soumyadipta

    2007-10-01

    Full Text Available Abstract Background It has been suggested that Brain-Computer Interfaces (BCI may one day be suitable for controlling a neuroprosthesis. For closed-loop operation of BCI, a tactile feedback channel that is compatible with neuroprosthetic applications is desired. Operation of an EEG-based BCI using only vibrotactile feedback, a commonly used method to convey haptic senses of contact and pressure, is demonstrated with a high level of accuracy. Methods A Mu-rhythm based BCI using a motor imagery paradigm was used to control the position of a virtual cursor. The cursor position was shown visually as well as transmitted haptically by modulating the intensity of a vibrotactile stimulus to the upper limb. A total of six subjects operated the BCI in a two-stage targeting task, receiving only vibrotactile biofeedback of performance. The location of the vibration was also systematically varied between the left and right arms to investigate location-dependent effects on performance. Results and Conclusion Subjects are able to control the BCI using only vibrotactile feedback with an average accuracy of 56% and as high as 72%. These accuracies are significantly higher than the 15% predicted by random chance if the subject had no voluntary control of their Mu-rhythm. The results of this study demonstrate that vibrotactile feedback is an effective biofeedback modality to operate a BCI using motor imagery. In addition, the study shows that placement of the vibrotactile stimulation on the biceps ipsilateral or contralateral to the motor imagery introduces a significant bias in the BCI accuracy. This bias is consistent with a drop in performance generated by stimulation of the contralateral limb. Users demonstrated the capability to overcome this bias with training.

  16. Tactile-Sight: A Sensory Substitution Device Based on Distance-Related Vibrotactile Flow

    Directory of Open Access Journals (Sweden)

    Leandro Cancar

    2013-06-01

    Full Text Available Sensory substitution is a research field of increasing interest with regard to technical, applied and theoretical issues. Among the latter, it is of central interest to understand the form in which humans perceive the environment. Ecological psychology, among other approaches, proposes that we can detect higher-order informational variables (in the sense that they are defined over substantial spatial and temporal intervals that specify our interaction with the environment. When using a vibrotactile sensory substitution device, it is reasonable to ask if stimulation on the skin may be exploitable to detect higher-order variables. Motivated by this question, a portable vibrotactile sensory substitution device was built, using distance-based information as a source and driving a large number of vibrotactile actuators (72 in the reported version, 120 max. The portable device was designed to explore real environments, allowing natural unrestricted movement for the user while providing contingent real-time vibrotactile information. Two preliminary experiments were performed. In the first one, participants were asked to detect the time to contact of an approaching ball in a simulated (desktop environment. Reasonable performance was observed in all experimental conditions, including the one with only tactile stimulation. In the second experiment, a portable version of the device was used in a real environment, where participants were asked to hit an approaching ball. Participants were able to coordinate their arm movements with vibrotactile stimulation in appropriate timing. We conclude that vibrotactile flow can be generated by distance-based activation of the actuators and that this stimulation on the skin allows users to perceive time-to-contact related environmental properties.

  17. First Insights with a Vibrotactile Interface for Children with Multiple Disabilities

    DEFF Research Database (Denmark)

    Manresa-Yee, Cristina; Morrison, Ann; Jordi Muntaner, Joan

    2015-01-01

    Designing and evaluating interactive systems for users with multiple disabilities is a challenge due to their cognitive, sensory, physical and behavioral conditions. Vibrotactile interfaces to motivate users’ actions exist for users with hearing and sight impairments, but there are hardly any...... for users with multiple disabilities. We developed V-Sense, a vibrotactile interface that encourages children with multiple disabilities to move their arms by using vibrations and exploiting the saltation perceptual illusion. In this paper we describe our initial experience evaluating the interface with 5...... children for 7 weeks and we discuss the first insights concerning the use of the interface and the difficulties encountered while conducting the evaluation sessions....

  18. Vibrotactile spatial acuity on the torso : effects of location and timingparameters

    NARCIS (Netherlands)

    Erp, J.B.F. van

    2005-01-01

    The processing of spatio-temporal vibrotactile patterns by the torso was examined in two experiments. The first investigated the spatial acuity as function of location on the torso. A uniform acuity between 2 and 3 cm was found, except on the body midline where acuity was about 1 cm. This favorable

  19. Vibrotactile and visual threat cueing with high g threat intercept in dynamic flight simulation

    NARCIS (Netherlands)

    Eriksson, L.; Erp, J.B.F. van; Carlander, O.; Levin, B.; Veen, H.A.H.C. van; Veltman, J.E.

    2006-01-01

    In a TNO and FOI joint study, nine fighter pilots participated in a threat detection and intercept experiment in the Swedish Dynamic Flight Simulator. Visual threat cueing with a simulated Gripen aircraft head-up display (HUD) symbology was compared with combined visual and vibrotactile threat

  20. Multisensory Narrative Tracking by a Profoundly Deaf Subject Using an Electrocutaneous Vocoder and a Vibrotactile Aid.

    Science.gov (United States)

    Lynch, Michael P.; And Others

    1989-01-01

    The study assessed the ability to track connected discourse by a congenitally profoundly deaf adult using an electrocutaneous vocoder and/or a vibrotactile aid in conjunction with or without lipreading and aided hearing. Overall, improvement in tracking performance occurred within and across phases of the study. (Author/DB)

  1. Effects of attractive versus repulsive vibrotactile instructional cues during motion replication tasks.

    Science.gov (United States)

    Lee, Beom-Chan; Sienko, Kathleen H

    2011-01-01

    The Mobile Instrument for Motion Instruction and Correction (MIMIC) enables an expert (i.e., physical therapist) to map his/her movements to a trainee (i.e., patient) in a hands-free fashion. MIMIC comprises an Expert Module (EM) and a Trainee Module (TM); both modules include six-degree-of-freedom inertial measurement units, microcontrollers, and batteries. The TM also includes actuators that provide the trainee with vibrotactile instructional cues. The estimated expert body motion information is transmitted wirelessly to the trainee; based on the computed difference between the motions of the expert and trainee, directional instructions are displayed to the trainee's skin via vibrotactile stimulation. This study examined anterior-posterior trunk movements using a simplified version of the MIMIC system in which only two actuators were used to provide feedback and pre-recorded target trajectories were used to represent ideal expert movements. The study was designed to investigate the effects of attractive versus repulsive vibrotactile instructional cues when the motion speed and task complexity were varied. Preliminary results (n = 12) suggest that repulsive vibrotactile instructional cues lead to the greatest correlation between expert and subject motion, the least time delay, and the least tilt error.

  2. Multisensory Training can Promote or Impede Visual Perceptual Learning of Speech Stimuli: Visual-Tactile versus Visual-Auditory Training

    Directory of Open Access Journals (Sweden)

    Silvio P Eberhardt

    2014-10-01

    Full Text Available In a series of studies we have been investigating how multisensory training affects unisensory perceptual learning with speech stimuli. Previously, we reported that Aaudiovisual training with speech stimuli can promote auditory-only perceptual learning in normal-hearing adults but can impede learning in congenitally deaf adults with late-acquired cochlear implants. Here, impeder and promoter effects were sought in normal-hearing adults who participated in lipreading training. In Experiment 1, visual-only (VO training on paired associations between CVCVC nonsense word videos and nonsense pictures demonstrated that VO words could be learned to a high level of accuracy even by poor lipreaders. In Experiment 2, visual-auditory (VA training in the same paradigm but with the addition of synchronous vocoded acoustic speech impeded VO learning of the stimuli in the paired-associates paradigm. In Experiment 3, the vocoded auditory-only (AO stimuli were shown to be less informative than the VO speech. Experiment 4 combined vibrotactile speech stimuli with the visual stimuli during training. Vibrotactile stimuli were shown to promote visual perceptual learning in participants whose training scores were similar. In Experiment 5, no-training controls were used to show that training with visual speech carried over to consonant identification of untrained CVCVC stimuli but not to lipreading words in sentences. Across this and previous studies, multisensory training effects depended on the functional relationship between pathways engaged during training. Two principles are proposed to account for stimulus effects: (1 Stimuli presented to the trainee’s primary perceptual pathway will impede learning by a lower-rank pathway. (2 Stimuli presented to the trainee’s lower rank perceptual pathway will promote learning by a higher-rank pathway. The mechanisms supporting these principles are discussed in light of multisensory reverse hierarchy theory.

  3. Multisensory training can promote or impede visual perceptual learning of speech stimuli: visual-tactile vs. visual-auditory training.

    Science.gov (United States)

    Eberhardt, Silvio P; Auer, Edward T; Bernstein, Lynne E

    2014-01-01

    In a series of studies we have been investigating how multisensory training affects unisensory perceptual learning with speech stimuli. Previously, we reported that audiovisual (AV) training with speech stimuli can promote auditory-only (AO) perceptual learning in normal-hearing adults but can impede learning in congenitally deaf adults with late-acquired cochlear implants. Here, impeder and promoter effects were sought in normal-hearing adults who participated in lipreading training. In Experiment 1, visual-only (VO) training on paired associations between CVCVC nonsense word videos and nonsense pictures demonstrated that VO words could be learned to a high level of accuracy even by poor lipreaders. In Experiment 2, visual-auditory (VA) training in the same paradigm but with the addition of synchronous vocoded acoustic speech impeded VO learning of the stimuli in the paired-associates paradigm. In Experiment 3, the vocoded AO stimuli were shown to be less informative than the VO speech. Experiment 4 combined vibrotactile speech stimuli with the visual stimuli during training. Vibrotactile stimuli were shown to promote visual perceptual learning. In Experiment 5, no-training controls were used to show that training with visual speech carried over to consonant identification of untrained CVCVC stimuli but not to lipreading words in sentences. Across this and previous studies, multisensory training effects depended on the functional relationship between pathways engaged during training. Two principles are proposed to account for stimulus effects: (1) Stimuli presented to the trainee's primary perceptual pathway will impede learning by a lower-rank pathway. (2) Stimuli presented to the trainee's lower rank perceptual pathway will promote learning by a higher-rank pathway. The mechanisms supporting these principles are discussed in light of multisensory reverse hierarchy theory (RHT).

  4. Enhanced Design of a Soft Thin-Film Vibrotactile Actuator Based on PVC Gel

    Directory of Open Access Journals (Sweden)

    Won-Hyeong Park

    2017-09-01

    Full Text Available We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to stimulate human skin in a wide frequency range. To achieve this, we investigate the working principle of the PVC gel and suggest a new structure in which most of electric energy contributes to the deformation of the PVC gel. Due to this structure, the vibrational amplitude of the proposed PVC gel actuator could considerably increase (0.816 g (g = 9.8 m/s2 at resonant frequency. The vibrotactile amplitude is proportional to the amount of input voltage. It increased from 0.05 g up to 0.416 g with increasing applied voltages from 200 V to 1 kV at 1 Hz. The experimental results show that the proposed actuator can create a variety of haptic sensations.

  5. The Effects of Verbal Pain Stimuli on the Behavior of Children.

    Science.gov (United States)

    Dubanoski, Richard A.; Tokioka, Abe B.

    1981-01-01

    Presented children (N=96) aged 8-11 with verbal pain or nonpain stimuli contingent or noncontingent on a target response. Delivered stimuli within an aggressive or nonaggressive setting and with or without affect. Type of setting did not influence the behavior, but stimuli delivered in an affective manner did facilitate responding. (Author/RC)

  6. Using space and time to encode vibrotactile information: toward an estimate of the skin's achievable throughput.

    Science.gov (United States)

    Novich, Scott D; Eagleman, David M

    2015-10-01

    Touch receptors in the skin can relay various forms of abstract information, such as words (Braille), haptic feedback (cell phones, game controllers, feedback for prosthetic control), and basic visual information such as edges and shape (sensory substitution devices). The skin can support such applications with ease: They are all low bandwidth and do not require a fine temporal acuity. But what of high-throughput applications? We use sound-to-touch conversion as a motivating example, though others abound (e.g., vision, stock market data). In the past, vibrotactile hearing aids have demonstrated improvement in speech perceptions in the deaf. However, a sound-to-touch sensory substitution device that works with high efficacy and without the aid of lipreading has yet to be developed. Is this because skin simply does not have the capacity to effectively relay high-throughput streams such as sound? Or is this because the spatial and temporal properties of skin have not been leveraged to full advantage? Here, we begin to address these questions with two experiments. First, we seek to determine the best method of relaying information through the skin using an identification task on the lower back. We find that vibrotactile patterns encoding information in both space and time yield the best overall information transfer estimate. Patterns encoded in space and time or "intensity" (the coupled coding of vibration frequency and force) both far exceed performance of only spatially encoded patterns. Next, we determine the vibrotactile two-tacton resolution on the lower back-the distance necessary for resolving two vibrotactile patterns. We find that our vibratory motors conservatively require at least 6 cm of separation to resolve two independent tactile patterns (>80 % correct), regardless of stimulus type (e.g., spatiotemporal "sweeps" versus single vibratory pulses). Six centimeter is a greater distance than the inter-motor distances used in Experiment 1 (2.5 cm), which

  7. Irrelevant sensory stimuli interfere with working memory storage: evidence from a computational model of prefrontal neurons.

    Science.gov (United States)

    Bancroft, Tyler D; Hockley, William E; Servos, Philip

    2013-03-01

    The encoding of irrelevant stimuli into the memory store has previously been suggested as a mechanism of interference in working memory (e.g., Lange & Oberauer, Memory, 13, 333-339, 2005; Nairne, Memory & Cognition, 18, 251-269, 1990). Recently, Bancroft and Servos (Experimental Brain Research, 208, 529-532, 2011) used a tactile working memory task to provide experimental evidence that irrelevant stimuli were, in fact, encoded into working memory. In the present study, we replicated Bancroft and Servos's experimental findings using a biologically based computational model of prefrontal neurons, providing a neurocomputational model of overwriting in working memory. Furthermore, our modeling results show that inhibition acts to protect the contents of working memory, and they suggest a need for further experimental research into the capacity of vibrotactile working memory.

  8. Auris System: Providing Vibrotactile Feedback for Hearing Impaired Population

    Directory of Open Access Journals (Sweden)

    Felipe Alves Araujo

    2017-01-01

    Full Text Available Deafness, an issue that affects millions of people around the globe, is manifested in different intensities and related to many causes. This impairment negatively affects different aspects of the social life of the deaf people, and music-centered situations (concerts, religious events, etc. are obviously not inviting for them. The Auris System was conceived to provide the musical experimentation for people who have some type of hearing loss. This system is able to extract musical information from audio and create a representation for music pieces using different stimuli, a new media format to be interpreted by other senses than the hearing. In addition, the system defines a testing methodology based on a noninvasive brain activity recording using an electroencephalographic (EEG device. The results of the tests are being used to better understand the human musical cognition, in order to improve the accuracy of the Auris musical representation.

  9. Auris System: Providing Vibrotactile Feedback for Hearing Impaired Population.

    Science.gov (United States)

    Alves Araujo, Felipe; Lima Brasil, Fabricio; Candido Lima Santos, Allison; de Sousa Batista Junior, Luzenildo; Pereira Fonseca Dutra, Savio; Eduardo Coelho Freire Batista, Carlos

    2017-01-01

    Deafness, an issue that affects millions of people around the globe, is manifested in different intensities and related to many causes. This impairment negatively affects different aspects of the social life of the deaf people, and music-centered situations (concerts, religious events, etc.) are obviously not inviting for them. The Auris System was conceived to provide the musical experimentation for people who have some type of hearing loss. This system is able to extract musical information from audio and create a representation for music pieces using different stimuli, a new media format to be interpreted by other senses than the hearing. In addition, the system defines a testing methodology based on a noninvasive brain activity recording using an electroencephalographic (EEG) device. The results of the tests are being used to better understand the human musical cognition, in order to improve the accuracy of the Auris musical representation.

  10. The Impact of Training Approaches on Experimental SetUp and Design of Wearable Vibrotactiles for Hunting Dogs

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Møller, Rune Heide; Manresa-Yee, Cristina

    2016-01-01

    While designing a wearable vibrotactile solution to assist canine navigation we encountered multiple conflicting dog training methods that impacted heavily on design possibilities as well as the methods used in the experimental design. The VibroTactile Vest (VTV), was designed in an iterative...... process to provide vibrotactile commands to dogs, working with variable-intensity vibrating motors mounted to a modified hug shirt to keep the vibrators close but not restrict movement. We folded knowledge gained from instructional scenarios with trainers, handlers and owners and from working directly...... with four hunting dogs who had been trained in either obedience, hunting, competitive or non-competitive styles into the finished design. We contribute to research that incorporates technology to enhance communication and mobility with working and companion animals. We increment foundational research...

  11. The effect of real-time vibrotactile feedback delivered through an augmented fork on eating rate, satiation, and food intake

    NARCIS (Netherlands)

    Hermans, R.C.J.; Hermsen, A.S.; Robinson, E.; Higgs, S.; Mars, M.; Frost, J.H.

    2017-01-01

    Eating rate is a basic determinant of appetite regulation, as people who eat more slowly feel sated earlier and eat less. Without assistance, eating rate is difficult to modify due to its automatic nature. In the current study, participants used an augmented fork that aimed to decelerate their rate

  12. Robot-Assisted Proprioceptive Training with Added Vibro-Tactile Feedback Enhances Somatosensory and Motor Performance.

    Science.gov (United States)

    Cuppone, Anna Vera; Squeri, Valentina; Semprini, Marianna; Masia, Lorenzo; Konczak, Jürgen

    2016-01-01

    This study examined the trainability of the proprioceptive sense and explored the relationship between proprioception and motor learning. With vision blocked, human learners had to perform goal-directed wrist movements relying solely on proprioceptive/haptic cues to reach several haptically specified targets. One group received additional somatosensory movement error feedback in form of vibro-tactile cues applied to the skin of the forearm. We used a haptic robotic device for the wrist and implemented a 3-day training regimen that required learners to make spatially precise goal-directed wrist reaching movements without vision. We assessed whether training improved the acuity of the wrist joint position sense. In addition, we checked if sensory learning generalized to the motor domain and improved spatial precision of wrist tracking movements that were not trained. The main findings of the study are: First, proprioceptive acuity of the wrist joint position sense improved after training for the group that received the combined proprioceptive/haptic and vibro-tactile feedback (VTF). Second, training had no impact on the spatial accuracy of the untrained tracking task. However, learners who had received VTF significantly reduced their reliance on haptic guidance feedback when performing the untrained motor task. That is, concurrent VTF was highly salient movement feedback and obviated the need for haptic feedback. Third, VTF can be also provided by the limb not involved in the task. Learners who received VTF to the contralateral limb equally benefitted. In conclusion, somatosensory training can significantly enhance proprioceptive acuity within days when learning is coupled with vibro-tactile sensory cues that provide feedback about movement errors. The observable sensory improvements in proprioception facilitates motor learning and such learning may generalize to the sensorimotor control of the untrained motor tasks. The implications of these findings for

  13. Robot-Assisted Proprioceptive Training with Added Vibro-Tactile Feedback Enhances Somatosensory and Motor Performance.

    Directory of Open Access Journals (Sweden)

    Anna Vera Cuppone

    Full Text Available This study examined the trainability of the proprioceptive sense and explored the relationship between proprioception and motor learning. With vision blocked, human learners had to perform goal-directed wrist movements relying solely on proprioceptive/haptic cues to reach several haptically specified targets. One group received additional somatosensory movement error feedback in form of vibro-tactile cues applied to the skin of the forearm. We used a haptic robotic device for the wrist and implemented a 3-day training regimen that required learners to make spatially precise goal-directed wrist reaching movements without vision. We assessed whether training improved the acuity of the wrist joint position sense. In addition, we checked if sensory learning generalized to the motor domain and improved spatial precision of wrist tracking movements that were not trained. The main findings of the study are: First, proprioceptive acuity of the wrist joint position sense improved after training for the group that received the combined proprioceptive/haptic and vibro-tactile feedback (VTF. Second, training had no impact on the spatial accuracy of the untrained tracking task. However, learners who had received VTF significantly reduced their reliance on haptic guidance feedback when performing the untrained motor task. That is, concurrent VTF was highly salient movement feedback and obviated the need for haptic feedback. Third, VTF can be also provided by the limb not involved in the task. Learners who received VTF to the contralateral limb equally benefitted. In conclusion, somatosensory training can significantly enhance proprioceptive acuity within days when learning is coupled with vibro-tactile sensory cues that provide feedback about movement errors. The observable sensory improvements in proprioception facilitates motor learning and such learning may generalize to the sensorimotor control of the untrained motor tasks. The implications of these

  14. Interactive Furniture: Bi-directional Interaction with a Vibrotactile Wearable Sensate Vest in an Urban Space

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Leegaard, Jack Højholt; Manresa, Cristina

    2017-01-01

    reveals some patterns on the vest and zones at the wall im-pact relaxation in the form of calming and feel-good sensations, (even therapeu-tic) as well as activation and warning on the vest. We contribute to this research field by adding a large scale public object and visibly responsive interactive wall...... that was positively received as the partner responder for the wearers of a vi-brotactile vest set in an urban environment. Participants reported calming, thera-peutic, feel good sensations in response to the patterns....

  15. Visual conflict and cognitive load modify postural responses to vibrotactile noise

    Science.gov (United States)

    2014-01-01

    Background Underlying the increased incidence of falls during multitasking is a reduced ability to detect or attend to the sensory information signaling postural instability. Adding noise to a biological system has been shown to enhance the detection and transmission of weakened or sub-threshold cutaneous signals. If stochastic resonance is to become an effective adjunct to rehabilitation, we need to determine whether vibrotactile noise can be effective when added to an environment presenting with other sensory noise. Methods Sub-threshold vibration noise was applied for 30 sec at the soles of the feet in 21 healthy adults (20–29 yrs) between two 30-sec periods of no vibration. During the trials, subjects stood quietly with eyes closed or while viewing a visual scene that rotated in continuous upward pitch at 30 deg/sec. Subjects were also tested with these two visual conditions while performing a mental calculation task. It was hypothesized that sub-threshold vibration would increase regularity of postural sway, thereby improving postural stabilization during an attention demanding task but exerting less effect with multiple sensory demands. An ellipse fit to the covariance matrix revealed excursion of center of pressure (COP) and center of mass (COM) responses in the anterior-posterior and lateral planes. RMS values and approximate entropy of the COP and COM were calculated and statistically compared. Results The addition of vibrotactile noise to the plantar surface during quiet stance with eyes closed reduced the area of the COM and COP responses, which then returned to pre-vibration levels after vibration was removed. Postural sway was generally increased with both visual field rotations and mental calculation compared to the eyes closed condition. The effect of sub-threshold vibratory noise on postural behavior was modified when visual field rotations and mental calculation was combined. It was shown that the measure of approximate entropy reflected

  16. Robot-assisted training to improve proprioception does benefit from added vibro-tactile feedback.

    Science.gov (United States)

    Cuppone, A; Squeri, V; Semprini, M; Konczak, J

    2015-01-01

    Proprioception is central for motor control and its role must also be taken into account when designing motor rehabilitation training protocols. This is particularly important when dealing with motor deficits due to proprioceptive impairment such as peripheral sensory neuropathy. In these cases substituting or augmenting diminished proprioceptive sensory information might be beneficial for improving motor function. However it still remains to be understood how proprioceptive senses can be improved by training, how this would translate into motor improvement and whether additional sensory modalities during motor training contribute to the sensorimotor training process. This preliminary study investigated how proprioceptive/haptic training can be augmented by providing additional sensory information in the form of vibro-tactile feedback. We tested the acuity of the wrist proprioceptive position sense before and after robotic training in two groups of healthy subjects, one trained only with haptic feedback and one with haptic and vibro-tactile feedback. We found that only the group receiving the multimodal feedback significantly improved proprioceptive acuity. This study demonstrates that non-proprioceptive position feedback derived from another somatosensory modality is easily interpretable for humans and can contribute to an increased precision of joint position. The clinical implications of this finding will be outlined.

  17. Hand Motion-Based Remote Control Interface with Vibrotactile Feedback for Home Robots

    Directory of Open Access Journals (Sweden)

    Juan Wu

    2013-06-01

    Full Text Available This paper presents the design and implementation of a hand-held interface system for the locomotion control of home robots. A handheld controller is proposed to implement hand motion recognition and hand motion-based robot control. The handheld controller can provide a ‘connect-and-play’ service for the users to control the home robot with visual and vibrotactile feedback. Six natural hand gestures are defined for navigating the home robots. A three-axis accelerometer is used to detect the hand motions of the user. The recorded acceleration data are analysed and classified to corresponding control commands according to their characteristic curves. A vibration motor is used to provide vibrotactile feedback to the user when an improper operation is performed. The performances of the proposed hand motion-based interface and the traditional keyboard and mouse interface have been compared in robot navigation experiments. The experimental results of home robot navigation show that the success rate of the handheld controller is 13.33% higher than the PC based controller. The precision of the handheld controller is 15.4% more than that of the PC and the execution time is 24.7% less than the PC based controller. This means that the proposed hand motion-based interface is more efficient and flexible.

  18. Adding vibrotactile feedback to a myoelectric-controlled hand improves performance when online visual feedback is disturbed.

    Science.gov (United States)

    Raveh, Eitan; Portnoy, Sigal; Friedman, Jason

    2018-01-17

    We investigated whether adding vibrotactile feedback to a myoelectric-controlled hand, when visual feedback is disturbed, can improve performance during a functional test. For this purpose, able-bodied subjects, activating a myoelectric-controlled hand attached to their right hand performed the modified Box & Blocks test, grasping and manipulating wooden blocks over a partition. This was performed in 3 conditions, using a repeated-measures design: in full light, in a dark room where visual feedback was disturbed and no auditory feedback - one time with the addition of tactile feedback provided during object grasping and manipulation, and one time without any tactile feedback. The average time needed to transfer one block was measured, and an infrared camera was used to give information on the number of grasping errors during performance of the test. Our results show that when vibrotactile feedback was provided, performance time was reduced significantly, compared with when no vibrotactile feedback was available. Furthermore, the accuracy of grasping and manipulation was improved, reflected by significantly fewer errors during test performance. In conclusion, adding vibrotactile feedback to a myoelectric-controlled hand has positive effects on functional performance when visual feedback is disturbed. This may have applications to current myoelectric-controlled hands, as adding tactile feedback may help prosthesis users to improve their functional ability during daily life activities in different environments, particularly when limited visual feedback is available or desirable. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Vibrotactile Language

    DEFF Research Database (Denmark)

    Morrison, Ann Judith

    2015-01-01

    We designed a wearable vest that houses a set of actuators that were placed at specific points on the myofascial lines of the body. We built a large interactive vibrotaoustic work named The Humming Wall for interacting with the vest and general public use. Vest wearers can see, hear and feel thei...

  20. A wearable device for real-time motion error detection and vibrotactile instructional cuing.

    Science.gov (United States)

    Lee, Beom-Chan; Chen, Shu; Sienko, Kathleen H

    2011-08-01

    We have developed a mobile instrument for motion instruction and correction (MIMIC) that enables an expert (i.e., physical therapist) to map his/her movements to a trainee (i.e., patient) in a hands-free fashion. MIMIC comprises an expert module (EM) and a trainee module (TM). Both the EM and TM are composed of six-degree-of-freedom inertial measurement units, microcontrollers, and batteries. The TM also has an array of actuators that provide the user with vibrotactile instructional cues. The expert wears the EM, and his/her relevant body position is computed by an algorithm based on an extended Kalman filter that provides asymptotic state estimation. The captured expert body motion information is transmitted wirelessly to the trainee, and based on the computed difference between the expert and trainee motion, directional instructions are displayed via vibrotactile stimulation to the skin. The trainee is instructed to move in the direction of the vibration sensation until the vibration is eliminated. Two proof-of-concept studies involving young, healthy subjects were conducted using a simplified version of the MIMIC system (pre-specified target trajectories representing ideal expert movements and only two actuators) during anterior-posterior trunk movements. The first study was designed to investigate the effects of changing the expert-trainee error thresholds (0.5(°), 1.0(°), and 1.5(°)) and varying the nature of the control signal (proportional, proportional plus derivative). Expert-subject cross-correlation values were maximized (0.99) and average position errors (0.33(°)) and time delays (0.2 s) were minimized when the controller used a 0.5(°) error threshold and proportional plus derivative feedback control signal. The second study used the best performing activation threshold and control signal determined from the first study to investigate subject performance when the motion task complexity and speed were varied. Subject performance decreased as motion

  1. Vibrotactile display for mobile applications based on dielectric elastomer stack actuators

    Science.gov (United States)

    Matysek, Marc; Lotz, Peter; Flittner, Klaus; Schlaak, Helmut F.

    2010-04-01

    Dielectric elastomer stack actuators (DESA) offer the possibility to build actuator arrays at very high density. The driving voltage can be defined by the film thickness, ranging from 80 μm down to 5 μm and driving field strength of 30 V/μm. In this paper we present the development of a vibrotactile display based on multilayer technology. The display is used to present several operating conditions of a machine in form of haptic information to a human finger. As an example the design of a mp3-player interface is introduced. To build up an intuitive and user friendly interface several aspects of human haptic perception have to be considered. Using the results of preliminary user tests the interface is designed and an appropriate actuator layout is derived. Controlling these actuators is important because there are many possibilities to present different information, e.g. by varying the driving parameters. A built demonstrator is used to verify the concept: a high recognition rate of more than 90% validates the concept. A characterization of mechanical and electrical parameters proofs the suitability of dielectric elastomer stack actuators for the use in mobile applications.

  2. Vibrotactile sensitivity threshold: nonlinear stochastic mechanotransduction model of the Pacinian Corpuscle.

    Science.gov (United States)

    Biswas, Abhijit; Manivannan, M; Srinivasan, Mandayam A

    2015-01-01

    Based on recent discoveries of stretch and voltage activated ion channels in the receptive area of the Pacinian Corpuscle (PC), this paper describes a two-stage mechanotransduction model of its near threshold Vibrotactile (VT) sensitivity valid over 10 Hz to a few kHz. The model is based on the nonlinear and stochastic behavior of the ion channels represented as dependent charge sources loaded with membrane impedance. It simulates the neural response of the PC considering the morphological and statistical properties of the receptor potential and action potential with the help of an adaptive relaxation pulse frequency modulator. This model also simulates the plateaus and nonmonotonic saturation of spike rate characteristics. The stochastic simulation based on the addition of mechanical and neural noise describes that the VT Sensitivity Threshold (VTST) at higher frequencies is more noise dependent. Above 800 Hz even a SNR = 150 improves the neurophysiological VTST more than 3 dBμ. In that frequency range, an absence of the entrainment threshold and a lower sensitivity index near the absolute threshold make the upper bound of the psychophysical VTST more dependent on the experimental protocol and physical set-up. This model can be extended to simulate the neural response of a group of PCs.

  3. Vibrotactile Perception of Segmental Features of Speech: A Comparison of Single-Channel and Multichannel Instruments.

    Science.gov (United States)

    Carney, Arlene Earley

    1988-01-01

    The recognition performance for segmental stimuli was compared when presented through a single-channel tactile device and through a 24-channel vocoder. Both consonant and vowel stimuli were tested under visual only, tactile only, and visual/tactile conditions. Results indicated no significant performance differences for the 12 artificially…

  4. Continuously informing vibrotactile displays in support of attention management and multitasking in anesthesiology.

    Science.gov (United States)

    Ferris, Thomas K; Sarter, Nadine

    2011-12-01

    A novel vibrotactile display type was investigated to determine the potential benefits for supporting the attention and task management of anesthesiologists. Recent research has shown physiological monitoring and multitasking performance can benefit from displaying patient data via alarm-like tactile notifications and via continuously informing auditory displays (e.g., sonifications). The current study investigated a novel combination of these two approaches: continuously informing tactile displays. A tactile alarm and two continuously informing tactile display designs were evaluated in an anesthesia induction simulation with anesthesiologists as participants. Several performance measures were collected for two tasks: physiological monitoring and anesthesia induction. A multitask performance score equivalently weighted components from each task, normalized across experimental scenarios. Subjective rankings of the displays were also collected. Compared to the baseline (visual and auditory only) display configuration, each tactile display significantly improved performance in several objective measures, including multitask performance score. The continuously informing display that encoded the severity of patient health into the salience of its signals supported significantly better performance than the other two tactile displays. Contrasting the objective results, participants subjectively ranked the tactile alarm display highest. Continuously informing tactile displays with alarm-like properties (e.g., salience mapping) can better support anesthesiologists' physiological monitoring and multitasking performance under the high task demands of anesthesia induction. Adaptive display mechanisms may improve user acceptance. This study can inform display design to support multitasking performance of anesthesiologists in the clinical setting and other supervisory control operators in work domains characterized by high demands for visual and auditory resources.

  5. Antivertiginous drug therapy does not hinder the efficacy of individualized vibrotactile neurofeedback training for vestibular rehabilitation - a randomized trial.

    Science.gov (United States)

    Basta, Dietmar; Borsellino, Liliana; Ernst, Arne

    2017-12-01

    Vestibular rehabilitation using individualized vibrotactile neurofeedback training (IVNT) can lead to significant improvement in the postural stability of patients with vestibular symptoms of different origins. However, some of these patients have complex, severe dizziness, meaning that a pharmacological pretreatment or parallel (to vestibular rehabilitation) treatment can help them perform the rehabilitation exercises. Hence, the present study investigated the influence of a pharmacological treatment on the efficacy of vibrotactile neurofeedback training in patients with chronic, noncompensated vestibulopathies. All participants performed IVNT for ∼10 min each day for 2 weeks. In addition, every second participant was selected randomly to receive oral medication (20 mg cinnarizine and 40 mg dimenhydrinate per tablet), taking three tables per day. Trunk and ankle sway and postural stability were measured. In addition, the dizziness handicap inventory was evaluated immediately before training on the last day of training and 6 months after training. After the 10-day period of IVNT, both groups showed a statistically significant improvement in all parameters tested. A follow-up analysis after 6 months showed a long-term efficacy for the IVNT, that is, the patients remained significantly improved in their postural stability. The antivertiginous therapy did not hinder the efficacy of the IVNT. The present results indicate that IVNT even in combination with an antivertiginous drug therapy is an effective treatment regime for patients with disabling vertigo of different origins.

  6. A wearable vibrotactile biofeedback system improves balance control of healthy young adults following perturbations from quiet stance.

    Science.gov (United States)

    Ma, Christina Zong-Hao; Lee, Winson Chiu-Chun

    2017-10-01

    Maintaining postural equilibrium requires fast reactions and constant adjustments of the center of mass (CoM) position to prevent falls, especially when there is a sudden perturbation of the support surface. During this study, a newly developed wearable feedback system provided immediate vibrotactile clues to users based on plantar force measurement, in an attempt to reduce reaction time and CoM displacement in response to a perturbation of the floor. Ten healthy young adults participated in this study. They stood on a support surface, which suddenly moved in one of four horizontal directions (forward, backward, left and right), with the biofeedback system turned on or off. The testing sequence of the four perturbation directions and the two system conditions (turned on or off) was randomized. The resulting reaction time and CoM displacement were analysed. Results showed that the vibrotactile feedback system significantly improved balance control during translational perturbations. The positive results of this preliminary study highlight the potential of a plantar force measurement based biofeedback system in improving balance under perturbations of the support surface. Future system optimizations could facilitate its application in fall prevention in real life conditions, such as standing in buses or trains that suddenly decelerate or accelerate. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2013-01-01

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

  8. Effects of kinematic vibrotactile feedback on learning to control a virtual prosthetic arm.

    Science.gov (United States)

    Hasson, Christopher J; Manczurowsky, Julia

    2015-03-24

    After a limb is lost a prosthesis can restore function. For maximum utility, prosthetic limbs should accept movement commands and provide force and motion feedback, which can be conveyed with vibrotactile feedback (VIBF). While prior studies have shown that force-based VIBF benefits control, the merits of motion-based VIBF are unclear. Our goal was to clarify the effectiveness of position- and velocity-based VIBF for prosthetic arm control. Healthy adults with normal limb function practiced a goal-directed task with a virtual myoelectric prosthetic arm. A linear resonant actuator on the wrist provided VIBF. Two groups with nine subjects each received amplitude modulated VIBF in addition to visual feedback while practicing the task. In one group, the VIBF was proportional to the virtual arm's position, and in the other group, velocity. A control group of nine subjects received only visual feedback. Subjects practiced for 240 trials, followed by 180 trials with feedback manipulations for the VIBF groups. Performance was characterized by end-point error, movement time, and a composite skill measure that combined these quantities. A second experiment with a new group of five subjects assessed discrimination capabilities between different position- and velocity-based VIBF profiles. With practice all groups improved their skill in controlling the virtual prosthetic arm. Subjects who received additional position- and velocity-based VIBF learned at the same rate as the control group, who received only visual feedback (learning rate time constant: about 40 trials). When visual feedback was subsequently removed leaving only VIBF, performance was no better than with no feedback at all. When VIBF was removed leaving only visual feedback, about half of the participants performed better, instead of worse. The VIBF discrimination tests showed that subjects could detect virtual arm angular position and velocity differences of about 5 deg and 20 deg/s, respectively. Kinematic

  9. 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,

  10. Configurable, wearable sensing and vibrotactile feedback system for real-time postural balance and gait training: proof-of-concept.

    Science.gov (United States)

    Xu, Junkai; Bao, Tian; Lee, Ung Hee; Kinnaird, Catherine; Carender, Wendy; Huang, Yangjian; Sienko, Kathleen H; Shull, Peter B

    2017-10-11

    Postural balance and gait training is important for treating persons with functional impairments, however current systems are generally not portable and are unable to train different types of movements. This paper describes a proof-of-concept design of a configurable, wearable sensing and feedback system for real-time postural balance and gait training targeted for home-based treatments and other portable usage. Sensing and vibrotactile feedback are performed via eight distributed, wireless nodes or "Dots" (size: 22.5 × 20.5 × 15.0 mm, weight: 12.0 g) that can each be configured for sensing and/or feedback according to movement training requirements. In the first experiment, four healthy older adults were trained to reduce medial-lateral (M/L) trunk tilt while performing balance exercises. When trunk tilt deviated too far from vertical (estimated via a sensing Dot on the lower spine), vibrotactile feedback (via feedback Dots placed on the left and right sides of the lower torso) cued participants to move away from the vibration and back toward the vertical no feedback zone to correct their posture. A second experiment was conducted with the same wearable system to train six healthy older adults to alter their foot progression angle in real-time by internally or externally rotating their feet while walking. Foot progression angle was estimated via a sensing Dot adhered to the dorsal side of the foot, and vibrotactile feedback was provided via feedback Dots placed on the medial and lateral sides of the mid-shank cued participants to internally or externally rotate their foot away from vibration. In the first experiment, the wearable system enabled participants to significantly reduce trunk tilt and increase the amount of time inside the no feedback zone. In the second experiment, all participants were able to adopt new gait patterns of internal and external foot rotation within two minutes of real-time training with the wearable system. These results suggest

  11. Can solar power deliver?

    Science.gov (United States)

    Nelson, Jenny; Emmott, Christopher J M

    2013-08-13

    Solar power represents a vast resource which could, in principle, meet the world's needs for clean power generation. Recent growth in the use of photovoltaic (PV) technology has demonstrated the potential of solar power to deliver on a large scale. Whilst the dominant PV technology is based on crystalline silicon, a wide variety of alternative PV materials and device concepts have been explored in an attempt to decrease the cost of the photovoltaic electricity. This article explores the potential for such emerging technologies to deliver cost reductions, scalability of manufacture, rapid carbon mitigation and new science in order to accelerate the uptake of solar power technologies.

  12. Good vibrations? Vibrotactile self-stimulation reveals anticipation of body-related action effects in motor control.

    Science.gov (United States)

    Pfister, Roland; Janczyk, Markus; Gressmann, Marcel; Fournier, Lisa R; Kunde, Wilfried

    2014-03-01

    Previous research suggests that motor actions are intentionally generated by recollecting their sensory consequences. Whereas this has been shown to apply to visual or auditory consequences in the environment, surprisingly little is known about the contribution of immediate, body-related consequences, such as proprioceptive and tactile reafferences. Here, we report evidence for a contribution of vibrotactile reafferences to action selection by using a response-effect compatibility paradigm. More precisely, anticipating actions to cause spatially incompatible vibrations delayed responding to a small but reliable degree. Whereas this observation suggests functional equivalence of body-related and environment-related reafferences to action control, the future application of the described experimental procedure might reveal functional peculiarities of specific types of sensory consequences in action control.

  13. Multisensory Processing of Gustatory Stimuli.

    Science.gov (United States)

    Simon, S A; de Araujo, I E; Stapleton, J R; Nicolelis, M A L

    2008-06-01

    Gustatory perception is inherently multimodal, since approximately the same time that intra-oral stimuli activate taste receptors, somatosensory information is concurrently sent to the CNS. We review evidence that gustatory perception is intrinsically linked to concurrent somatosensory processing. We will show that processing of multisensory information can occur at the level of the taste cells through to the gustatory cortex. We will also focus on the fact that the same chemical and physical stimuli that activate the taste system also activate the somatosensory system (SS), but they may provide different types of information to guide behavior.

  14. 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…

  15. Subconscious Subliminal Stimuli And rrrsssssshhhppp!

    DEFF Research Database (Denmark)

    Lewis Brooks, Anthony

    2003-01-01

    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...

  16. 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. To distinguish different objects in a natural scene, the brain must segment the image into regions corresponding to objects. The so-called "border-ownership" cells appear to be dedicated to this task, as they signal for a given edge on which side the object is that owns it. Here, we report that individual border-ownership cells are unreliable when tested across

  17. Effects of multi-directional vibrotactile feedback on vestibular-deficient postural performance during continuous multi-directional support surface perturbations.

    Science.gov (United States)

    Sienko, K H; Balkwill, M D; Oddsson, L I E; Wall, C

    2008-01-01

    Single-axis vibrotactile feedback of trunk tilt provided in real-time has previously been shown to significantly reduce the root-mean-square (RMS) trunk sway in subjects with vestibular loss during single-axis perturbation. This research examines the effect of multi-directional vibrotactile feedback on postural sway during continuous multi-directional surface perturbations when the subjects' eyes are closed. Eight subjects with vestibular loss donned a multi-axis feedback device that mapped body tilt estimates onto their torsos with a 3-row by 16-column array of tactile actuators (tactors). Tactor row indicated tilt magnitude and tactor column indicated tilt direction. Root-mean-square trunk tilt, elliptical fits to trunk sway trajectory areas, percentage of time spent outside a no vibrotactile feedback zone, RMS center of pressure, and anchoring index parameters indicating intersegmental coordination were used to assess the efficacy of the multi-directional vibrotactile balance aid. Four tactor display configurations in addition to the tactors off configuration were evaluated. Subjects had significantly reduced RMS trunk sway, significantly smaller elliptical fits of the trajectory area, and spent significantly less time outside of the no feedback zone in the tactors on versus the tactors off configuration. Among the displays evaluated in this study, there was not an optimal tactor column configuration for standing tasks involving continuous surface perturbations. Furthermore, subjects performed worse when erroneous information was displayed. Therefore, a spatial resolution of 90 degrees (4 columns) seems to be as effective as a spatial resolution of 22.5 degrees (16 columns) for control of standing.

  18. Multisensory Processing of Gustatory Stimuli

    OpenAIRE

    Simon, S A; de Araujo, I.E.; Stapleton, J. R.; Nicolelis, M. A. L.

    2008-01-01

    Gustatory perception is inherently multimodal, since approximately the same time that intra-oral stimuli activate taste receptors, somatosensory information is concurrently sent to the CNS. We review evidence that gustatory perception is intrinsically linked to concurrent somatosensory processing. We will show that processing of multisensory information can occur at the level of the taste cells through to the gustatory cortex. We will also focus on the fact that the same chemical and physical...

  19. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35 tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which finished its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. "The production is proceeding well and we expect to be complete in October as previously foreseen," said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have been delivered.

  20. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35-tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which completed its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. 'The production is proceeding well and we expect to be complete in October as foreseen,' said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have already been delivered.

  1. Monitor, a Vibrotactile Aid for Environmental Perception: A Field Evaluation by Four People with Severe Hearing and Vision Impairment

    Directory of Open Access Journals (Sweden)

    Parivash Ranjbar

    2013-01-01

    Full Text Available Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44–54 years with Usher Syndrome I (three with tunnel vision and one with only light perception tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%–97% and 58%–95% with the directional microphone. The corresponding values in traffic were 29%–100% and 65%–100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds.

  2. Use of an Enactive Insole for Reducing the Risk of Falling on Different Types of Soil Using Vibrotactile Cueing for the Elderly.

    Directory of Open Access Journals (Sweden)

    Martin J-D Otis

    Full Text Available Our daily activities imply displacements on various types of soil. For persons with gait disorder or losing functional autonomy, walking on some types of soil could be challenging because of the risk of falling it represents.In this paper, we present, in a first part, the use of an enactive shoe for an automatic differentiation of several types of soil. In a second part, using a second improved prototype (an enactive insole, twelve participants with Parkinson's disease (PD and nine age-matched controls have performed the Timed Up and Go (TUG test on six types of soil with and without cueing. The frequency of the cueing was set at 10% above the cadence computed at the lower risk of falling (walking over the concrete. Depending on the cadence computed at the lower risk, the enactive insole activates a vibrotactile cueing aiming to improve gait and balance control. Finally, a risk index is computed using gait parameters in relation to given type of soil.The frequency analysis of the heel strike vibration allows the differentiation of various types of soil. The risk computed is associated to an appropriate rhythmic cueing in order to improve balance and gait impairment. The results show that a vibrotactile cueing could help to reduce the risk of falling.Firstly, this paper demonstrates the feasibility of reducing the risk of falling while walking on different types of soil using vibrotactile cueing. We found a significant difference and a significant decrease in the computed risks of falling for most of types of soil especially for deformable soils which can lead to fall. Secondly, heel strike provides an approximation of the impulse response of the soil that can be analyzed with time and frequency-domain modeling. From these analyses, an index is computed enabling differentiation the types of soil.

  3. Within, but not between hands interactions in vibrotactile detection thresholds reflect somatosensory receptive field organization

    Directory of Open Access Journals (Sweden)

    Luigi eTamè

    2014-02-01

    Full Text Available Detection of a tactile stimulus on one finger is impaired when a concurrent stimulus (masker is presented on an additional finger of the same or the opposite hand. This phenomenon is known to be finger-specific at the within-hand level. However, whether this specificity is also maintained at the between-hand level is not known. In four experiments, we addressed this issue by combining a Bayesian adaptive staircase procedure (QUEST with a two-interval forced choice (2IFC design in order to establish threshold for detecting 200ms, 100Hz sinusoidal vibrations applied to the index or little fingertip of either hand (targets. We systematically varied the masker finger (index, middle, ring, or little finger of either hand, while controlling the spatial location of the target and masker stimuli. Detection thresholds varied consistently as a function of the masker finger when the latter was on the same hand (Experiments 1 and 2, but not when on different hands (Experiments 3 and 4. Within the hand, detection thresholds increased for masker fingers closest to the target finger (i.e., middle>ring when the target was index. Between the hands, detection thresholds were higher only when the masker was present on any finger as compared to when the target was presented in isolation. The within hand effect of masker finger is consistent with the segregation of different fingers at the early stages of somatosensory processing, from the periphery to the primary somatosensory cortex (SI. We propose that detection is finger-specific and reflects the organisation of somatosensory receptive fields in SI within, but not between the hands.

  4. The Impact of Simultaneously Applying Normal Stress and Vibrotactile Stimulation for Feedback of Exteroceptive Information.

    Science.gov (United States)

    Reza Motamedi, M; Otis, Martin; Duchaine, Vincent

    2017-06-01

    Commercially available prosthetic hands do not convey any tactile information, forcing amputees to rely solely on visual attention. A promising solution to this problem is haptics, which could lead to new prostheses in which tactile information is conveyed between the amputee and the artificial limb. However, the haptic feedback must be optimized so that amputees can use it effectively; and although several studies have examined how specific haptic feedback systems can transmit certain types of tactile information, there has not yet been much research on the effects of superposing two or more types of feedback at the same location, which might prove to be more effective than using a single type of feedback alone. This paper investigates how the simultaneous application of two different types of haptic feedback-vibration and normal stress-impacts the human sensory perception of each separate feedback type. These stimuli were applied to glabrous skin on the forearms of 14 participants. Our experiments tested whether participants experienced more accurate sensory perception, compared to vibration or normal stress alone, when vibration was applied at the same time as the normal stress, at either the same location, or at a different location 6 cm away. Results indicate that although participants' perception of the normal stress diminished when vibration was applied at the same location, the same combination improved their perception of the vibration. Apparently, vibration has a negative impact upon the ability to perceive normal stress, whether applied at the same or a different location; whereas the opposite is true for the effect of normal stress upon the perception of vibration.

  5. 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.

  6. Development of the Korean Facial Emotion Stimuli: Korea University Facial Expression Collection 2nd Edition.

    Science.gov (United States)

    Kim, Sun-Min; Kwon, Ye-Jin; Jung, Soo-Yun; Kim, Min-Ji; Cho, Yang Seok; Kim, Hyun Taek; Nam, Ki-Chun; Kim, Hackjin; Choi, Kee-Hong; Choi, June-Seek

    2017-01-01

    Background: Developing valid emotional facial stimuli for specific ethnicities creates ample opportunities to investigate both the nature of emotional facial information processing in general and clinical populations as well as the underlying mechanisms of facial emotion processing within and across cultures. Given that most entries in emotional facial stimuli databases were developed with western samples, and given that very few of the eastern emotional facial stimuli sets were based strictly on the Ekman's Facial Action Coding System, developing valid emotional facial stimuli of eastern samples remains a high priority. Aims: To develop and examine the psychometric properties of six basic emotional facial stimuli recruiting professional Korean actors and actresses based on the Ekman's Facial Action Coding System for the Korea University Facial Expression Collection-Second Edition (KUFEC-II). Materials And Methods: Stimulus selection was done in two phases. First, researchers evaluated the clarity and intensity of each stimulus developed based on the Facial Action Coding System. Second, researchers selected a total of 399 stimuli from a total of 57 actors and actresses, which were then rated on accuracy, intensity, valence, and arousal by 75 independent raters. Conclusion: The hit rates between the targeted and rated expressions of the KUFEC-II were all above 80%, except for fear (50%) and disgust (63%). The KUFEC-II appears to be a valid emotional facial stimuli database, providing the largest set of emotional facial stimuli. The mean intensity score was 5.63 (out of 7), suggesting that the stimuli delivered the targeted emotions with great intensity. All positive expressions were rated as having a high positive valence, whereas all negative expressions were rated as having a high negative valence. The KUFEC II is expected to be widely used in various psychological studies on emotional facial expression. KUFEC-II stimuli can be obtained through contacting the

  7. Development of the Korean Facial Emotion Stimuli: Korea University Facial Expression Collection 2nd Edition

    Science.gov (United States)

    Kim, Sun-Min; Kwon, Ye-Jin; Jung, Soo-Yun; Kim, Min-Ji; Cho, Yang Seok; Kim, Hyun Taek; Nam, Ki-Chun; Kim, Hackjin; Choi, Kee-Hong; Choi, June-Seek

    2017-01-01

    Background: Developing valid emotional facial stimuli for specific ethnicities creates ample opportunities to investigate both the nature of emotional facial information processing in general and clinical populations as well as the underlying mechanisms of facial emotion processing within and across cultures. Given that most entries in emotional facial stimuli databases were developed with western samples, and given that very few of the eastern emotional facial stimuli sets were based strictly on the Ekman’s Facial Action Coding System, developing valid emotional facial stimuli of eastern samples remains a high priority. Aims: To develop and examine the psychometric properties of six basic emotional facial stimuli recruiting professional Korean actors and actresses based on the Ekman’s Facial Action Coding System for the Korea University Facial Expression Collection-Second Edition (KUFEC-II). Materials And Methods: Stimulus selection was done in two phases. First, researchers evaluated the clarity and intensity of each stimulus developed based on the Facial Action Coding System. Second, researchers selected a total of 399 stimuli from a total of 57 actors and actresses, which were then rated on accuracy, intensity, valence, and arousal by 75 independent raters. Conclusion: The hit rates between the targeted and rated expressions of the KUFEC-II were all above 80%, except for fear (50%) and disgust (63%). The KUFEC-II appears to be a valid emotional facial stimuli database, providing the largest set of emotional facial stimuli. The mean intensity score was 5.63 (out of 7), suggesting that the stimuli delivered the targeted emotions with great intensity. All positive expressions were rated as having a high positive valence, whereas all negative expressions were rated as having a high negative valence. The KUFEC II is expected to be widely used in various psychological studies on emotional facial expression. KUFEC-II stimuli can be obtained through contacting the

  8. Development of the Korean Facial Emotion Stimuli: Korea University Facial Expression Collection 2nd Edition

    Directory of Open Access Journals (Sweden)

    Sun-Min Kim

    2017-05-01

    Full Text Available Background: Developing valid emotional facial stimuli for specific ethnicities creates ample opportunities to investigate both the nature of emotional facial information processing in general and clinical populations as well as the underlying mechanisms of facial emotion processing within and across cultures. Given that most entries in emotional facial stimuli databases were developed with western samples, and given that very few of the eastern emotional facial stimuli sets were based strictly on the Ekman’s Facial Action Coding System, developing valid emotional facial stimuli of eastern samples remains a high priority.Aims: To develop and examine the psychometric properties of six basic emotional facial stimuli recruiting professional Korean actors and actresses based on the Ekman’s Facial Action Coding System for the Korea University Facial Expression Collection-Second Edition (KUFEC-II.Materials And Methods: Stimulus selection was done in two phases. First, researchers evaluated the clarity and intensity of each stimulus developed based on the Facial Action Coding System. Second, researchers selected a total of 399 stimuli from a total of 57 actors and actresses, which were then rated on accuracy, intensity, valence, and arousal by 75 independent raters.Conclusion: The hit rates between the targeted and rated expressions of the KUFEC-II were all above 80%, except for fear (50% and disgust (63%. The KUFEC-II appears to be a valid emotional facial stimuli database, providing the largest set of emotional facial stimuli. The mean intensity score was 5.63 (out of 7, suggesting that the stimuli delivered the targeted emotions with great intensity. All positive expressions were rated as having a high positive valence, whereas all negative expressions were rated as having a high negative valence. The KUFEC II is expected to be widely used in various psychological studies on emotional facial expression. KUFEC-II stimuli can be obtained through

  9. Phase shift of sinusoidally alternating colored stimuli

    NARCIS (Netherlands)

    Walraven, P.L.; Leebeek, H.J.

    1964-01-01

    In order to avoid luminance flicker at equal luminance of two alternating colored stimuli de Lange found that a phase shift of the stimuli with respect to each other has to be introduced. This compensation for the phase shift occurring in the retina-cortex system has been measured for a large number

  10. Binocular coordination in response to stereoscopic stimuli

    Science.gov (United States)

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

    2009-02-01

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

  11. Delivery of continuously-varying stimuli using ChR2

    Directory of Open Access Journals (Sweden)

    Tatjana eTchumatchenko

    2013-12-01

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

  12. 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.

  13. The Feasibility of Gelatin-Based Retronasal Stimuli to Assess Olfactory Perception

    Directory of Open Access Journals (Sweden)

    Daniel Shepherd

    2015-10-01

    Full Text Available Links between some psychological disorders and olfactory deficits are well documented, and screening tests have been developed to exploit these associations. Odors can take one of two routes to the olfactory receptors in the nasal epithelium, the orthonasal or retronasal route. This article discusses the potential use of the retronasal route to assess olfaction using gelatin-based stimuli delivered orally. Using a relatively new psychophysical method, the Single-Interval Adjustment Matrix task, we estimated vanillin thresholds for five healthy participants sampling small vanillin flavored gels. Our data demonstrate the feasibility of using solid-state gustatory stimuli to assess retronasal perception.

  14. A novel device for the study of somatosensory information processing

    OpenAIRE

    Holden, Jameson K; Nguyen, Richard H.; Francisco, Eric M.; ZHANG Zheng; Robert G Dennis; Tommerdahl, Mark

    2011-01-01

    Current methods for applying multi-site vibratory stimuli to the skin typically involve the use of multiple, individual vibrotactile stimulators. Limitations of such an arrangement include difficulty with both positioning the stimuli as well as ensuring that stimuli are delivered in a synchronized and deliberate manner. Previously, we reported a two-site tactile stimulator that was developed in order to solve these problems (Tannan et al., 2007a). Due to both the success of that novel stimula...

  15. Stimuli-responsive photoluminescent liquid crystals.

    Science.gov (United States)

    Yamane, Shogo; Tanabe, Kana; Sagara, Yoshimitsu; Kato, Takashi

    2012-01-01

    We describe mechanochromic and thermochromic photoluminescent liquid crystals. In particular, mechanochromic photoluminescent liquid crystals found recently, which are new stimuli-responsive materials are reported. For example, photoluminescent liquid crystals having bulky dendritic moieties with long alkyl chains change their photoluminescent colors by mechanical stimuli associated with isothermal phase transitions. The photoluminescent properties of molecular assemblies depend on their assembled structures. Therefore, controlling the structures of molecular assemblies with external stimuli leads to the development of stimuli-responsive luminescent materials. Mechanochromic photoluminescent properties are also observed for a photoluminescent metallomesogen and a liquid-crystalline polymer. We also show thermochromic photoluminescent liquid crystals based on origo-(p-phenylenevinylene) and anthracene moieties and a thermochromic photoluminescent metallocomplex.

  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. Stimuli-responsive dendrimers in drug delivery.

    Science.gov (United States)

    Wang, Hui; Huang, Quan; Chang, Hong; Xiao, Jianru; Cheng, Yiyun

    2016-03-01

    Dendrimers have shown great promise as carriers in drug delivery due to their unique structures and superior properties. However, the precise control of payload release from a dendrimer matrix still presents a great challenge. Stimuli-responsive dendrimers that release payloads in response to a specific trigger could offer distinct clinical advantages over those dendrimers that release payloads passively. These smart polymers are designed to specifically release their payloads at targeted regions or at constant release profiles for specific therapies. They represent an attractive alternative to targeted dendrimers and enable dendrimer-based therapeutics to be more effective, more convenient, and much safer. The wide range of stimuli, either endogenous (acid, enzyme, and redox potentials) or exogenous (light, ultrasound, and temperature change), allows great flexibility in the design of stimuli-responsive dendrimers. In this review article, we will highlight recent advances and opportunities in the development of stimuli-responsive dendrimers for the treatment of various diseases, with emphasis on cancer. Specifically, the applications of stimuli-responsive dendrimers in drug delivery as well as their mechanisms are intensively reviewed.

  18. Recall and recognition hypermnesia for Socratic stimuli.

    Science.gov (United States)

    Kazén, Miguel; Solís-Macías, Víctor M

    2016-01-01

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

  19. Vibrotactile and Vibroacoustic Communications

    DEFF Research Database (Denmark)

    Morrison, Ann; Manresa, Cristina; Knoche, Hendrik Ole

    2017-01-01

    period. Participants wearing the vest (and their pair) completed a set of tasks. We logged use and responses, recorded all activities on video, and conducted post-experiment interviews and questionnaires. Results: The results depicted the participants’ experience, communication and connection while...

  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. Cortical Local Field Potential Power Is Associated with Behavioral Detection of Near-threshold Stimuli in the Rat Whisker System: Dissociation between Orbitofrontal and Somatosensory Cortices.

    Science.gov (United States)

    Rickard, Rachel E; Young, Andrew M J; Gerdjikov, Todor V

    2018-01-01

    There is growing evidence that ongoing brain oscillations may represent a key regulator of attentional processes and as such may contribute to behavioral performance in psychophysical tasks. OFC appears to be involved in the top-down modulation of sensory processing; however, the specific contribution of ongoing OFC oscillations to perception has not been characterized. Here we used the rat whiskers as a model system to further characterize the relationship between cortical state and tactile detection. Head-fixed rats were trained to report the presence of a vibrotactile stimulus (frequency = 60 Hz, duration = 2 sec, deflection amplitude = 0.01-0.5 mm) applied to a single vibrissa. We calculated power spectra of local field potentials preceding the onset of near-threshold stimuli from microelectrodes chronically implanted in OFC and somatosensory cortex. We found a dissociation between slow oscillation power in the two regions in relation to detection probability: Higher OFC but not somatosensory delta power was associated with increased detection probability. Furthermore, coherence between OFC and barrel cortex was reduced preceding successful detection. Consistent with the role of OFC in attention, our results identify a cortical network whose activity is differentially modulated before successful tactile detection.

  2. The Haptic Bracelets: Learning Multi-Limb Rhythm Skills from Haptic Stimuli While Reading

    NARCIS (Netherlands)

    Bouwer, A.; Holland, S.; Dalgleish, M.; Holland, S.; Wilkie, K.; Mulholland, P.; Seago, A.

    2013-01-01

    The Haptic Bracelets are a system designed to help people learn multi-limbed rhythms (which involve multiple simultaneous rhythmic patterns) while they carry out other tasks. The Haptic Bracelets consist of vibrotactiles attached to each wrist and ankle, together with a computer system to control

  3. Incorporation of presleep stimuli into dream contents: evidence for a consolidation effect on declarative knowledge during REM sleep?

    Science.gov (United States)

    Cipolli, Carlo; Fagioli, Igino; Mazzetti, Michela; Tuozzi, Giovanni

    2004-12-01

    Presleep stimuli to be retained for further recall is often incorporated into dream contents. To establish whether processing for insertion into dream contents may improve consolidation, we compared the retention rate at delayed recall of contents resulting from incorporation of presleep sentence-stimuli with those of other contents of the same dream experiences. We hypothesized that association with a cognitive task of recall facilitates access to recently acquired items of declarative knowledge such as presleep stimuli, and triggers the deep elaboration of their semantic features, which involves rehearsal. Twelve subjects were given a task of delayed recall for three nonsense sentences delivered once a time before each of the sleep (re-)onsets over an experimental night. After each awakening in rapid eye movement sleep, subjects were asked to report dream experience and recall the sentence to be retained. In the morning, after spontaneous awakening, subjects were unexpectedly requested to again report their dream experiences and to recall the stimuli. Two pairs of judges independently identified possible incorporations of the stimuli, and parsed dream reports into propositional content units. The proportion of night reports with at least one incorporation of the stimulus delivered (i.e. valid incorporations) was higher than that of reports with contents similar to a stimulus(-i) not yet delivered (forward pseudo-incorporations) or delivered prior to an earlier sleep period (backward pseudo-incorporations). The proportion of content units common to night and morning reports (considered to be better consolidated) was significantly higher for incorporated contents than for other contents, including pseudo-incorporated contents. Instead, the retention at morning recall of words of sentence-stimuli corresponding to incorporated contents was not significantly higher than that of other words. The better retention of incorporated contents provides a partial confirmation

  4. A Simon Effect With Stationary Moving Stimuli

    Science.gov (United States)

    Bosbach, Simone; Prinz, Wolfgang; Kerzel, Dirk

    2004-01-01

    To clarify whether motion information per se has a separable influence on action control, the authors investigated whether irrelevant direction of motion of stimuli whose overall position was constant over time would affect manual left-right responses (i.e., reveal a motion-based Simon effect). In Experiments 1 and 2, significant Simon effects…

  5. Responses to Urban Stimuli: A Balanced Approach.

    Science.gov (United States)

    Geller, Daniel M.

    1980-01-01

    Proposes an alternative to Milgram's overload model of urban behavior. Suggests that intense, complex and/or novel stimuli may lead to positive as well as negative effects, and that this may vary across persons or over time. Presents data that confirm the importance of urban complexity as an organizing variable. (Author/GC)

  6. Threat modulates perception of looming visual stimuli.

    Science.gov (United States)

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

    2012-10-09

    Among the most critical of visual functions is the detection of potentially hazardous or threatening aspects of the environment. For example, objects on a collision course with an observer must be quickly identified to allow sufficient time to prepare appropriate defensive or avoidant responses. Directly approaching objects produce a specific accelerating pattern of optical expansion, known as 'looming, which in theory exactly specifies time-to-collision independent of object size or distance. Such looming stimuli have been shown to trigger stereotyped defensive responses in both monkeys [1] and human infants [2]. Psychophysical results in adult participants have similarly suggested sensitivity to looming at early stages of visual processing [3]. Such findings indicate specialization of the visual system to detect and react to such 'looming' stimuli, and have contributed to the traditional view of looming as a purely optical cue to imminent collision [1]. Here, we investigated whether the semantic content of a looming visual stimulus affects perceived time-to-collision by manipulating its threat value. We show that time-to-collision is underestimated for threatening (snakes and spiders) compared to non-threatening (butterflies and rabbits) stimuli. Further, the magnitude of this effect is correlated with self-reported fear. Our results demonstrate affective modulation of the perception of looming stimuli, and suggest that emotion shapes basic aspects of visual perception. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Preferential awareness of protofacial stimuli in autism

    NARCIS (Netherlands)

    Akechi, H.; Stein, T.; Kikuchi, Y.; Tojo, Y.; Osanai, H.; Hasegawa, T.

    2015-01-01

    It has been suggested that a subcortically mediated, innate sensitivity to protofacial stimuli leads to specialized face processing and to the development of the social brain. A dysfunction of this face-processing pathway has been associated with atypical social development in individuals with

  8. Responses of MST neurons to plaid stimuli.

    Science.gov (United States)

    Khawaja, Farhan A; Liu, Liu D; Pack, Christopher C

    2013-07-01

    The estimation of motion information from retinal input is a fundamental function of the primate dorsal visual pathway. Previous work has shown that this function involves multiple cortical areas, with each area integrating information from its predecessors. Compared with neurons in the primary visual cortex (V1), neurons in the middle temporal (MT) area more faithfully represent the velocity of plaid stimuli, and the observation of this pattern selectivity has led to two-stage models in which MT neurons integrate the outputs of component-selective V1 neurons. Motion integration in these models is generally complemented by motion opponency, which refines velocity selectivity. Area MT projects to a third stage of motion processing, the medial superior temporal (MST) area, but surprisingly little is known about MST responses to plaid stimuli. Here we show that increased pattern selectivity in MST is associated with greater prevalence of the mechanisms implemented by two-stage MT models: Compared with MT neurons, MST neurons integrate motion components to a greater degree and exhibit evidence of stronger motion opponency. Moreover, when tested with more challenging unikinetic plaid stimuli, an appreciable percentage of MST neurons are pattern selective, while such selectivity is rare in MT. Surprisingly, increased motion integration is found in MST even for transparent plaid stimuli, which are not typically integrated perceptually. Thus the relationship between MST and MT is qualitatively similar to that between MT and V1, as repeated application of basic motion mechanisms leads to novel selectivities at each stage along the pathway.

  9. Tempo-spatial discrimination is lower for noxious stimuli than for innocuous stimuli

    DEFF Research Database (Denmark)

    Frahm, Ken Steffen; Mørch, Carsten Dahl; Andersen, Ole Kæseler

    2017-01-01

    The exteroceptive sensory system is responsible for sensing external stimuli in relation to time and space. The aim of this study was to investigate the tempo-spatial properties of the exteroceptive system using painful laser heat and non-painful mechanical touch stimulation.Thirteen healthy...... by simultaneous stimuli at a point-to-point distance ranging from 10 to 100mm, in steps of 10mm. The subjects reported the intensity (0-10 NRS, 3: pain threshold) and either direction (line stimuli) or number of perceived points (2-point stimuli).All mechanical line stimulations were reported correctly, i...... for the mechanical stimulation (34.5mm). NRS increased both with line length and distance between the two points (Linear mixed model, p

  10. 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.

  11. Modeling auditory evoked potentials to complex stimuli

    DEFF Research Database (Denmark)

    Rønne, Filip Munch

    cochlear compression would be of great benefit, as a more precise diagnose of the deficits underlying a potential hearing impairment in both infants and adults could be obtained. It was demonstrated in this thesis, via experimental recordings and supported by model simulations, that the growth of the ASSR....... Sensorineural hearing impairments is commonly associated with a loss of outer hair-cell functionality, and a measurable consequence is the decreased amount of cochlear compression at frequencies corresponding to the damaged locations in the cochlea. In clinical diagnostics, a fast and objective measure of local...... 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...

  12. Binocular coordination in response to stereoscopic stimuli.

    OpenAIRE

    Liversedge, S.P.; Holliman, N. S.; Blythe, H.I.

    2009-01-01

    Humans actively explore their visual environment by moving their eyes. Precise coordination of the eyes during visual scanning underlies the experience of a unified perceptual representation and is important for the perception of depth. We report data from three psychological experiments investigating human binocular coordination during visual processing of stereoscopic stimuli.In the first experiment participants were required to read sentences that contained a stereoscopically presented tar...

  13. Explicit Emotion Regulation: Comparing Emotion Inducing Stimuli

    OpenAIRE

    Suman Dhaka; Naveen Kashyap

    2017-01-01

    Emotions are a major part of our subjective experiences of the world. At times, our emotions are not appropriate and require active management. Emotion regulation refers to the various ways of managing or controlling emotional responses. External stimuli play specific role in electing emotions. Pictures and movies elicit emotions and emotional effects of films are believed to exceed that of pictures. The aim of the present study is to compare the effectiveness of emotion regulation strategies...

  14. Receptors and transduction of umami taste stimuli.

    Science.gov (United States)

    Kinnamon, Sue C; Vandenbeuch, Aurelie

    2009-07-01

    L-glutamate and 5'-ribonucleotides, such as GMP and IMP, elicit the "umami" taste, also known as the fifth taste. This review will highlight recent advancements in our understanding of umami taste receptors and their downstream signaling effectors in taste receptor cells. Several G protein-coupled receptors that bind umami stimuli have been identified in taste buds, including the heterodimer T1R1/T1R3, truncated and brain forms of mGluR4 and mGluR1, brain mGluR2, and brain mGluR3. Further, ionotropic glutamate receptors are expressed in taste cells and may play a role in glutamate transduction or signaling between taste cells and/or nerve fibers. Knockout of T1R1 or T1R3 reduces, but does not eliminate, responses to umami stimuli, suggesting that multiple receptors contribute to umami taste. The signaling effectors downstream of umami G protein-coupled receptors involve Gbetagamma activation of PLCbeta2 to elicit Ca(2+) release from intracellular stores and activation of a cation channel, TRPM5. In fungiform and palatal taste buds, T1R1/T1R3 is co-expressed with Galpha gustducin and transducin, but the Galpha proteins involved in circumvallate taste buds have not been identified. In most taste fields, however, cAMP antagonizes responses to umami stimuli, suggesting that the Galpha subunit serves to modulate umami taste sensitivity.

  15. 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.

  16. Vibrotactile Detection, Identification and Directional Perception of signal-Processed Sounds from Environmental Events: A Pilot Field Evaluation in Five Cases

    Directory of Open Access Journals (Sweden)

    Parivash Ranjbar

    2008-09-01

    Full Text Available Objectives: Conducting field tests of a vibrotactile aid for deaf/deafblind persons for detection, identification and directional perception of environmental sounds. Methods: Five deaf (3F/2M, 22–36 years individuals tested the aid separately in a home environment (kitchen and in a traffic environment. Their eyes were blindfolded and they wore a headband and holding a vibrator for sound identification. In the headband, three microphones were mounted and two vibrators for signalling direction of the sound source. The sounds originated from events typical for the home environment and traffic. The subjects were inexperienced (events unknown and experienced (events known. They identified the events in a home and traffic environment, but perceived sound source direction only in traffic. Results: The detection scores were higher than 98% both in the home and in the traffic environment. In the home environment, identification scores varied between 25%-58% when the subjects were inexperienced and between 33%-83% when they were experienced. In traffic, identification scores varied between 20%-40% when the subjects were inexperienced and between 22%-56% when they were experienced. The directional perception scores varied between 30%-60% when inexperienced and between 61%-83% when experienced. Discussion: The vibratory aid consistently improved all participants’ detection, identification and directional perception ability.

  17. Modulation of Auditory Responses to Speech vs. Nonspeech Stimuli during Speech Movement Planning.

    Science.gov (United States)

    Daliri, Ayoub; Max, Ludo

    2016-01-01

    Previously, we showed that the N100 amplitude in long latency auditory evoked potentials (LLAEPs) elicited by pure tone probe stimuli is modulated when the stimuli are delivered during speech movement planning as compared with no-speaking control conditions. Given that we probed the auditory system only with pure tones, it remained unknown whether the nature and magnitude of this pre-speech auditory modulation depends on the type of auditory stimulus. Thus, here, we asked whether the effect of speech movement planning on auditory processing varies depending on the type of auditory stimulus. In an experiment with nine adult subjects, we recorded LLAEPs that were elicited by either pure tones or speech syllables when these stimuli were presented prior to speech onset in a delayed-response speaking condition vs. a silent reading control condition. Results showed no statistically significant difference in pre-speech modulation of the N100 amplitude (early stages of auditory processing) for the speech stimuli as compared with the nonspeech stimuli. However, the amplitude of the P200 component (later stages of auditory processing) showed a statistically significant pre-speech modulation that was specific to the speech stimuli only. Hence, the overall results from this study indicate that, immediately prior to speech onset, modulation of the auditory system has a general effect on early processing stages but a speech-specific effect on later processing stages. This finding is consistent with the hypothesis that pre-speech auditory modulation may play a role in priming the auditory system for its role in monitoring auditory feedback during speech production.

  18. Delivering Science from Big Data

    Science.gov (United States)

    Quinn, Peter Joseph

    2015-08-01

    The SKA will be capable of producing a stream of science data products that are Exa-scale in terms of their storage and processing requirements. This Google-scale enterprise is attracting considerable international interest and excitement from within the industrial and academic communities. In this paper we examine the data flow, storage and processing requirements of a number of key SKA survey science projects to be executed on the baseline SKA1 configuration. Based on a set of conservative assumptions about trends for HPC and storage costs, and the data flow process within the SKA Observatory, it is apparent that survey projects of the scale proposed will potentially drive construction and operations costs beyond the current anticipated SKA1 budget. This implies a sharing of the resources and costs to deliver SKA science between the community and what is contained within the SKA Observatory. A similar situation was apparent to the designers of the LHC more than 10 years ago. We propose that it is time for the SKA project and broader community to consider the effort and process needed to design and implement a distributed science data system that leans on the lessons of other projects and looks to recent developments in Cloud technologies to ensure an affordable, effective and global achievement of science goals.

  19. Differences in apparent straightness of dot and line stimuli.

    Science.gov (United States)

    Parlee, M. B.

    1972-01-01

    An investigation has been made of anisotropic responses to contoured and noncontoured stimuli to obtain an insight into the way these stimuli are processed. For this purpose, eight subjects judged the alignment of minimally contoured (3 dot) and contoured (line) stimuli. Stimuli, presented to each eye separately, vertically subtended either 8 or 32 deg visual angle and were located 10 deg left, center, or 10 deg right in the visual field. Location-dependent deviations from physical straightness were larger for dot stimuli than for lines. The results were the same for the two eyes. In a second experiment, subjects judged the alignment of stimuli composed of different densities of dots. Apparent straightness for these stimuli was the same as for lines. The results are discussed in terms of alternative mechanisms for analysis of contoured and minimally contoured stimuli.

  20. Effect of Size Change and Brightness Change of Visual Stimuli on Loudness Perception and Pitch Perception of Auditory Stimuli

    Directory of Open Access Journals (Sweden)

    Syouya Tanabe

    2011-10-01

    Full Text Available People obtain a lot of information from visual and auditory sensation on daily life. Regarding the effect of visual stimuli on perception of auditory stimuli, studies of phonological perception and sound localization have been made in great numbers. This study examined the effect of visual stimuli on perception in loudness and pitch of auditory stimuli. We used the image of figures whose size or brightness was changed as visual stimuli, and the sound of pure tone whose loudness or pitch was changed as auditory stimuli. Those visual and auditory stimuli were combined independently to make four types of audio-visual multisensory stimuli for psychophysical experiments. In the experiments, participants judged change in loudness or pitch of auditory stimuli, while they judged the direction of size change or the kind of a presented figure in visual stimuli. Therefore they cannot neglect visual stimuli while they judged auditory stimuli. As a result, perception in loudness and pitch were promoted significantly around their difference limen, when the image was getting bigger or brighter, compared with the case in which the image had no changes. This indicates that perception in loudness and pitch were affected by change in size and brightness of visual stimuli.

  1. Stimuli-Responsive Polymers for Actuation.

    Science.gov (United States)

    Zhang, Qiang Matthew; Serpe, Michael J

    2017-06-02

    A variety of stimuli-responsive polymers have been developed and used as actuators and/or artificial muscles, with the movement being driven by an external stimulus, such as electrical potential. This Review highlights actuators constructed from liquid-crystal elastomers, dielectric elastomers, ionic polymers, and conducting polymers. The Review covers recent examples of a variety of actuators generated from these materials and their utility. The mechanism of actuation will be detailed for most examples in order to stimulate possible future research, and lead to new applications and advanced applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Vibrotactile Identification of Signal-Processed Sounds from Environmental Events Presented by a Portable Vibrator: A Laboratory Study

    Directory of Open Access Journals (Sweden)

    Parivash Ranjbar

    2008-09-01

    Full Text Available Objectives: To evaluate different signal-processing algorithms for tactile identification of environmental sounds in a monitoring aid for the deafblind. Two men and three women, sensorineurally deaf or profoundly hearing impaired with experience of vibratory experiments, age 22-36 years. Methods: A closed set of 45 representative environmental sounds were processed using two transposing (TRHA, TR1/3 and three modulating algorithms (AM, AMFM, AMMC and presented as tactile stimuli using a portable vibrator in three experiments. The algorithms TRHA, TR1/3, AMFM and AMMC had two alternatives (with and without adaption to vibratory thresholds. In Exp. 1, the sounds were preprocessed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB, and processed in real time. Results: In Exp. 1, Algorithm AMFM and AMFM(A consistently had the lowest identification scores, and were thus excluded in Exp. 2 and 3. TRHA, AM, AMMC, and AMMC(A showed comparable identification scores (30%-42% and the addition of noise did not deteriorate the performance. Discussion: Algorithm TRHA, AM, AMMC, and AMMC(A showed good performance in all three experiments and were robust in noise they can therefore be used in further testing in real environments.

  3. Viability of spectral enhancement with harmonic stimuli

    Science.gov (United States)

    Digiovanni, Jeffrey J.

    2003-04-01

    Loss of spectral resolution is an established consequence of sensorineural hearing loss. Traditional hearing aid design includes amplification and compression. These do not, however, account for the loss in frequency resolution. Recently, spectral enhancement processing has been designed to at least partially restore aspects of frequency resolution. The critical feature of this design is to increase the peak to trough ratio of the speech spectrum. These have been implemented with mixed success [e.g., Miller et al. (1999); Franck et al. (1999)]. More recently, DiGiovanni et al. (2002) showed promising results for normal and hearing-impaired subjects with psychophysical noise stimuli. The goal of this study was to expand these results to harmonic stimuli while adding peaks at fixed formant places within the spectrum. In that regard, subjects listened in two psychophysical experiments: detecting an F2-like spectral increment in a broadband harmonic complex and detecting the increment with an additional fixed formant peak added at an appropriate F1 place. Preliminary results show that normally hearing subjects have an improved ability to detect a narrowband tone complex when there is a spectral decrement at frequencies adjacent to the increment. These results are further support that the idea of spectral enhancement is viable.

  4. The subjective duration of audiovisual looming and receding stimuli.

    Science.gov (United States)

    Grassi, Massimo; Pavan, Andrea

    2012-08-01

    Looming visual stimuli (log-increasing in proximal size over time) and auditory stimuli (of increasing sound intensity over time) have been shown to be perceived as longer than receding visual and auditory stimuli (i.e., looming stimuli reversed in time). Here, we investigated whether such asymmetry in subjective duration also occurs for audiovisual looming and receding stimuli, as well as for stationary stimuli (i.e., stimuli that do not change in size and/or intensity over time). Our results showed a great temporal asymmetry in audition but a null asymmetry in vision. In contrast, the asymmetry in audiovision was moderate, suggesting that multisensory percepts arise from the integration of unimodal percepts in a maximum-likelihood fashion.

  5. Oral perceptions of fat and taste stimuli are modulated by affect and mood induction.

    Directory of Open Access Journals (Sweden)

    Petra Platte

    Full Text Available This study examined the impact of three clinical psychological variables (non-pathological levels of depression and anxiety, as well as experimentally manipulated mood on fat and taste perception in healthy subjects. After a baseline orosensory evaluation, 'sad', 'happy' and 'neutral' video clips were presented to induce corresponding moods in eighty participants. Following mood manipulation, subjects rated five different oral stimuli, appearing sweet, umami, sour, bitter, fatty, which were delivered at five different concentrations each. Depression levels were assessed with Beck's Depression Inventory (BDI and anxiety levels were assessed via the Spielberger's STAI-trait and state questionnaire. Overall, subjects were able to track the concentrations of the stimuli correctly, yet depression level affected taste ratings. First, depression scores were positively correlated with sucrose ratings. Second, subjects with depression scores above the sample median rated sucrose and quinine as more intense after mood induction (positive, negative and neutral. Third and most important, the group with enhanced depression scores did not rate low and high fat stimuli differently after positive or negative mood induction, whereas, during baseline or during the non-emotional neutral condition they rated the fat intensity as increasing with concentration. Consistent with others' prior observations we also found that sweet and bitter stimuli at baseline were rated as more intense by participants with higher anxiety scores and that after positive and negative mood induction, citric acid was rated as stronger tasting compared to baseline. The observation that subjects with mild subclinical depression rated low and high fat stimuli similarly when in positive or negative mood is novel and likely has potential implications for unhealthy eating patterns. This deficit may foster unconscious eating of fatty foods in sub-clinical mildly depressed populations.

  6. Oral perceptions of fat and taste stimuli are modulated by affect and mood induction.

    Science.gov (United States)

    Platte, Petra; Herbert, Cornelia; Pauli, Paul; Breslin, Paul A S

    2013-01-01

    This study examined the impact of three clinical psychological variables (non-pathological levels of depression and anxiety, as well as experimentally manipulated mood) on fat and taste perception in healthy subjects. After a baseline orosensory evaluation, 'sad', 'happy' and 'neutral' video clips were presented to induce corresponding moods in eighty participants. Following mood manipulation, subjects rated five different oral stimuli, appearing sweet, umami, sour, bitter, fatty, which were delivered at five different concentrations each. Depression levels were assessed with Beck's Depression Inventory (BDI) and anxiety levels were assessed via the Spielberger's STAI-trait and state questionnaire. Overall, subjects were able to track the concentrations of the stimuli correctly, yet depression level affected taste ratings. First, depression scores were positively correlated with sucrose ratings. Second, subjects with depression scores above the sample median rated sucrose and quinine as more intense after mood induction (positive, negative and neutral). Third and most important, the group with enhanced depression scores did not rate low and high fat stimuli differently after positive or negative mood induction, whereas, during baseline or during the non-emotional neutral condition they rated the fat intensity as increasing with concentration. Consistent with others' prior observations we also found that sweet and bitter stimuli at baseline were rated as more intense by participants with higher anxiety scores and that after positive and negative mood induction, citric acid was rated as stronger tasting compared to baseline. The observation that subjects with mild subclinical depression rated low and high fat stimuli similarly when in positive or negative mood is novel and likely has potential implications for unhealthy eating patterns. This deficit may foster unconscious eating of fatty foods in sub-clinical mildly depressed populations.

  7. Effects of paired transcutaneous electrical stimulation delivered at single and dual sites over lumbosacral spinal cord.

    Science.gov (United States)

    Sayenko, Dimitry G; Atkinson, Darryn A; Floyd, Terrance C; Gorodnichev, Ruslan M; Moshonkina, Tatiana R; Harkema, Susan J; Edgerton, V Reggie; Gerasimenko, Yury P

    2015-11-16

    It was demonstrated previously that transcutaneous electrical stimulation of multiple sites over the spinal cord is more effective in inducing robust locomotor behavior as compared to the stimulation of single sites alone in both animal and human models. To explore the effects and mechanisms of interactions during multi-site spinal cord stimulation we delivered transcutaneous electrical stimulation to the single or dual locations over the spinal cord corresponding to approximately L2 and S1 segments. Spinally evoked motor potentials in the leg muscles were investigated using single and paired pulses of 1ms duration with conditioning-test intervals (CTIs) of 5 and 50ms. We observed considerable post-stimulation modulatory effects which depended on CTIs, as well as on whether the paired stimuli were delivered at a single or dual locations, the rostro-caudal relation between the conditioning and test stimuli, and on the muscle studied. At CTI-5, the paired stimulation delivered at single locations (L2 or S1) provided strong inhibitory effects, evidenced by the attenuation of the compound responses as compared with responses from either single site. In contrast, during L2-S1 paradigm, the compound responses were potentiated. At CTI-50, the magnitude of inhibition did not differ among paired stimulation paradigms. Our results suggest that electrical stimuli delivered to dual sites over the lumbosacral enlargement in rostral-to-caudal order, may recruit different populations of motor neurons initially through projecting sensory and intraspinal connections and then directly, resulting in potentiation of the compound spinally evoked motor potentials. The interactive and synergistic effects indicate multi-segmental convergence of descending and ascending influences on the neuronal circuitries during electrical spinal cord stimulation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Attribute amnesia is greatly reduced with novel stimuli

    Directory of Open Access Journals (Sweden)

    Weijia Chen

    2017-11-01

    Full Text Available Attribute amnesia is the counterintuitive phenomenon where observers are unable to report a salient aspect of a stimulus (e.g., its colour or its identity immediately after the stimulus was presented, despite both attending to and processing the stimulus. Almost all previous attribute amnesia studies used highly familiar stimuli. Our study investigated whether attribute amnesia would also occur for unfamiliar stimuli. We conducted four experiments using stimuli that were highly familiar (colours or repeated animal images or that were unfamiliar to the observers (unique animal images. Our results revealed that attribute amnesia was present for both sets of familiar stimuli, colour (p < .001 and repeated animals (p = .001; but was greatly attenuated, and possibly eliminated, when the stimuli were unique animals (p = .02. Our data shows that attribute amnesia is greatly reduced for novel stimuli.

  9. Vestibular rehabilitation with visual stimuli in peripheral vestibular disorders

    OpenAIRE

    Manso, Andréa; Ganança, Mauricio Malavasi; Caovilla, Heloisa Helena

    2016-01-01

    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...

  10. Color stimuli perception in presence of light scattering

    OpenAIRE

    OZONLINSH, Maris; Ikaunieks, Gatis; Karitans, Varis; Colomb, Michèle

    2006-01-01

    Perception of different color contrast stimuli was studied in the presence of light scattering: in a fog chamber in Clermont-Ferrand and in laboratory conditions where light scattering of similar levels was obtained, using different light scattering eye occluders. Blue (shortest wavelength) light is scattered in fog to the greatest extent, causing deterioration of vision quality especially for the monochromatic blue stimuli.However, for the color stimuli presented on a white backgrou...

  11. 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.

  12. Color stimuli perception in presence of light scattering.

    Science.gov (United States)

    Ozolinsh, Maris; Colomb, Michéle; Ikaunieks, Gatis; Karitans, Varis

    2006-01-01

    Perception of different color contrast stimuli was studied in the presence of light scattering: in a fog chamber in Clermont-Ferrand and in laboratory conditions where light scattering of similar levels was obtained, using different light scattering eye occluders. Blue (shortest wavelength) light is scattered in fog to the greatest extent, causing deterioration of vision quality especially for the monochromatic blue stimuli. However, for the color stimuli presented on a white background, visual acuity in fog for blue Landolt-C optotypes was higher than for red and green optotypes on the white background. The luminance of color Landolt-C optotypes presented on a LCD screen was chosen corresponding to the blue, green, and red color contributions in achromatic white stimuli (computer digital R, G, or B values for chromatic stimuli equal to RGB values in the achromatic white background) that results in the greatest luminance contrast for the white-blue stimuli, thus advancing the visual acuity for the white-blue stimuli. Besides such blue stimuli on the white background are displayed with a uniform, spatially unmodulated distribution of the screen blue phosphor emission over the entire area of the screen including the stimulus C optotype area. It follows that scattering, which has the greatest effect on the blue component of screen luminance, has the least effect on the perception of white-blue stimuli.

  13. 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.

  14. 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.

  15. Using visual stimuli to enhance gait control.

    Science.gov (United States)

    Rhea, Christopher K; Kuznetsov, Nikita A

    2017-01-01

    Gait control challenges commonly coincide with vestibular dysfunction and there is a long history in using balance and gait activities to enhance functional mobility in this population. While much has been learned using traditional rehabilitation exercises, there is a new line of research emerging that is using visual stimuli in a very specific way to enhance gait control. For example, avatars can be created in an individualized manner to incorporate specific gait characteristics. The avatar could then be used as a visual stimulus to which the patient can synchronize their own gait cycle. This line of research builds upon the rich history of sensorimotor control research in which augmented sensory information (visual, haptic, or auditory) is used to probe, and even enhance, human motor control. This review paper focuses on gait control challenges in patients with vestibular dysfunction, provides a brief historical perspective on how various visual displays have been used to probe sensorimotor and gait control, and offers some recommendations for future research.

  16. Psychophysiological Response Patterns to Affective Film Stimuli

    Science.gov (United States)

    Bos, Marieke G. N.; Jentgens, Pia; Beckers, Tom; Kindt, Merel

    2013-01-01

    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. PMID:23646134

  17. Delay Efficient Method for Delivering IPTV Services

    National Research Council Canada - National Science Library

    Sangamesh; Shilpa. K. Gowda

    2014-01-01

    Internet Protocol Television (IPTV) is a system through which Internet television services are delivered using the architecture and networking methods of the Internet Protocol Suite over a packet-switched network infrastructure, e.g...

  18. Product perception from sensory stimuli: the case of vacuum cleaner.

    Science.gov (United States)

    Almeida e Silva, Caio Márcio; Okimoto, Maria Lúciar R L; Tanure, Raffaela Leane Zenni

    2012-01-01

    This paper discusses the importance of consideration of different sensory stimuli in the perception of the product. So we conducted an experiment that examined whether there is a difference between the perception of sensory stimuli from artificially isolated. The result is an analysis of the different sensory modalities, relating them to product an between them.

  19. Sex Differences in Response to Visual Sexual Stimuli: A Review

    Science.gov (United States)

    Rupp, Heather A.; Wallen, Kim

    2009-01-01

    This article reviews what is currently known about how men and women respond to the presentation of visual sexual stimuli. While the assumption that men respond more to visual sexual stimuli is generally empirically supported, previous reports of sex differences are confounded by the variable content of the stimuli presented and measurement techniques. We propose that the cognitive processing stage of responding to sexual stimuli is the first stage in which sex differences occur. The divergence between men and women is proposed to occur at this time, reflected in differences in neural activation, and contribute to previously reported sex differences in downstream peripheral physiological responses and subjective reports of sexual arousal. Additionally, this review discusses factors that may contribute to the variability in sex differences observed in response to visual sexual stimuli. Factors include participant variables, such as hormonal state and socialized sexual attitudes, as well as variables specific to the content presented in the stimuli. Based on the literature reviewed, we conclude that content characteristics may differentially produce higher levels of sexual arousal in men and women. Specifically, men appear more influenced by the sex of the actors depicted in the stimuli while women’s response may differ with the context presented. Sexual motivation, perceived gender role expectations, and sexual attitudes are possible influences. These differences are of practical importance to future research on sexual arousal that aims to use experimental stimuli comparably appealing to men and women and also for general understanding of cognitive sex differences. PMID:17668311

  20. 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…

  1. Roll motion stimuli : sensory conflict, perceptual weighting and motion sickness

    NARCIS (Netherlands)

    Graaf, B. de; Bles, W.; Bos, J.E.

    1998-01-01

    In an experiment with seventeen subjects interactions of visual roll motion stimuli and vestibular body tilt stimuli were examined in determining the subjective vertical. Interindi-vidual differences in weighting the visual information were observed, but in general visual and vestibular responses

  2. Freeze or Flee? Negative Stimuli Elicit Selective Responding

    Science.gov (United States)

    Estes, Zachary; Verges, Michelle

    2008-01-01

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

  3. 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

  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. Imagery Arousal as a Function of Exposure to Artistic Stimuli.

    Science.gov (United States)

    Bilotta, Joseph

    The purpose of this study was to determine to what extent music and art can arouse imagery experiences in an audience. Because of the relationship found between imagery and the arts in past research, it was hypothesized that artistic stimuli would have a greater influence on imagery than other kinds of stimuli (art-information or non-artistic).…

  7. How Attention Modulates Encoding of Dynamic Stimuli

    Directory of Open Access Journals (Sweden)

    Noga Oren

    2016-10-01

    Full Text Available 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, which is evident in the prefrontal cortex sections 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 task increased. Activation analyses revealed that at higher load the frontal 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 frontal 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 correlation between memory strength and the modulation of the dPCC points to this

  8. Neuronal encoding of natural stimuli: the rat tactile system.

    Science.gov (United States)

    Diamond, Mathew E; Zorzin, Erik; Arabzadeh, Ehsan

    2006-01-01

    A major challenge of sensory systems neuroscience is to quantify the brain activity underlying perceptual experiences and to explain this activity as the outcome of elemental neuronal response properties. One strategy is to measure variations in neuronal response in relation to controlled variations in an artificial stimulus. The limitation is that the stimuli scarcely resemble those which the sensory system has evolved to process-natural, behaviourally relevant stimuli. A more recent strategy is to measure neuronal responses during presentation of natural stimuli, but such experiments have failed to predict the observed responses according to the fundamental properties of neurons. In the work described here, we focus on tactile sensation in rats, and try to bridge the gap between neurons' responses to natural stimuli and their responses to controlled, artificial stimuli. We focus on texture, a submodality in which the rat whisker sensory system excels. Because the physical characteristics of texture stimuli have not yet been studied, the first set of experiments measures textures from the whiskers' point of view. The second set of experiments describes neurons' responses to textures. The third set of experiments computes kernels (estimates of the extracted stimulus features) of sensory neurons using white noise and then tries to account for natural texture responses according to these kernels. These investigations suggest ways of using natural stimuli to assemble a more complete picture of the neuronal basis of tactile sensation.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Rebecca J Lepping

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

  11. 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.

  12. 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.

  13. Is International Accounting Education Delivering Pedagogical Value?

    Science.gov (United States)

    Patel, Chris; Millanta, Brian; Tweedie, Dale

    2016-01-01

    This paper examines whether universities are delivering pedagogical value to international accounting students commensurate with the costs of studying abroad. The paper uses survey and interview methods to explore the extent to which Chinese Learners (CLs) in an Australian postgraduate accounting subject have distinct learning needs. The paper…

  14. Delivering best care in war and peace.

    Science.gov (United States)

    Moore, Alison

    2014-06-24

    Col Alan Finnegan, the fi rst Ministry of Defence professor of nursing, is driving forward research into preparing nurses for deployment and ensuring they deliver the best care possible in war and peace. Research topics range from the role of autonomous practitioners to the effects on soldiers of injuries to their genitalia.

  15. Delivering Online Examinations: A Case Study

    Directory of Open Access Journals (Sweden)

    John MESSING

    2004-07-01

    Full Text Available Delivering Online Examinations: A Case Study Jason HOWARTH John MESSING Irfan ALTAS Charles Sturt University Wagga Wagga-AUSTRALIA ABSTRACT This paper represents a brief case study of delivering online examinations to a worldwide audience. These examinations are delivered in partnership with a commercial online testing company as part of the Industry Master’s degree at Charles Sturt University (CSU. The Industry Master’s degree is an academic program for students currently employed in the IT industry. Using Internet Based Testing (IBT, these students are examined in test centres throughout the world. This offers many benefits. For example, students have the freedom of sitting exams at any time during a designated interval. Computer-based testing also provides instructors with valuable feedback through test statistics and student comments. In this paper, we document CSU’s use of the IBT system, including how tests are built and delivered, and how both human and statistical feedback is used to evaluate and enhance the testing process.

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

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    .006) and was more intense (P = 0.001) within the zone of secondary hyperalgesia than on the lateral part of the crus. Further, the heat pain response was more intense in the zone of primary hyperalgesia than in the zone of secondary hyperalgesia (P = 0.004), in contrast to the mechanical pain response, which...... 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......, suggest differences in the mechanisms accounting for primary hyperalgesia to heat and mechanical stimuli, whereas secondary hyperalgesia to heat and mechanical stimuli may be explained by a common central mechanism....

  17. Emerging applications of stimuli-responsive polymer materials

    NARCIS (Netherlands)

    Stuart, M.A.C.; Genzer, J.; Muller, M.; Ober, C.; Stamm, M.; Sukhorukov, G.B.; Szleifer, I.; Tsukruk, V.V.; Urban, M.; Winnik, F.; Zauscher, S.; Luzinov, I.; Minko, S.

    2010-01-01

    Responsive polymer materials can adapt to surrounding environments, regulate transport of ions and molecules, change wettability and adhesion of different species on external stimuli, or convert chemical and biochemical signals into optical, electrical, thermal and mechanical signals, and vice

  18. Perceptual Sensitivity and Response to Strong Stimuli Are Related

    OpenAIRE

    Anna C. Bolders; Mattie Tops; Guido P H Band; Pieter Jan M. Stallen

    2017-01-01

    To shed new light on the long-standing debate about the (in)dependence 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 sti...

  19. Corticospinal excitability preceding the grasping of emotion-laden stimuli.

    Directory of Open Access Journals (Sweden)

    Anaelli Aparecida Nogueira-Campos

    Full Text Available Evolutionary theories posit that emotions prime organisms for action. This study examined whether corticospinal excitability (CSE is modulated by the emotional valence of a to-be-grasped stimulus. CSE was estimated based on the amplitude of motor evoked potentials (MEPs elicited using transcranial magnetic stimulation (TMS and recorded on the first dorsal interosseous (FDI muscle. Participants were instructed to grasp (ACTION condition or just look at (NO-ACTION condition unpleasant, pleasant and neutral stimuli. TMS pulses were applied randomly at 500 or 250 ms before a go signal. MEP amplitudes were normalized within condition by computing a ratio for the emotion-laden stimuli by reference to the neutral stimuli. A divergent valence effect was observed in the ACTION condition, where the CSE ratio was higher during the preparation to grasp unpleasant compared to pleasant stimuli. In addition, the CSE ratio was lower for pleasant stimuli during the ACTION condition compared to the NO-ACTION condition. Altogether, these results indicate that motor preparation is selectively modulated by the valence of the stimulus to be grasped. The lower CSE for pleasant stimuli may result from the need to refrain from executing an imminent action.

  20. 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.

  1. Technical Feasibility of Acoustic Coordinated Reset Therapy for Tinnitus Delivered via Hearing Aids: A Case Study

    Directory of Open Access Journals (Sweden)

    Christian Hauptmann

    2017-01-01

    Full Text Available Primary tinnitus has a severe negative influence on the quality of life of a substantial portion of the general population. When acoustic coordinated reset (CR neuromodulation stimuli are delivered for several hours per day over several weeks a clinically significant symptom reduction in patients with primary tonal tinnitus has been reported by several clinical sites. Here, we reported the first case where CR neuromodulation was delivered through a hearing aid. A 52-year-old man with chronic primary tonal tinnitus was previously considered untreatable with sound therapy. He initially received the classic CR treatment protocol with signals delivered with the separate proprietary device with his hearing aids removed during treatment. He was subsequently treated with the therapy being deployed through a set of contemporary hearing aids. After 5 months of classic CR treatment with the separate custom device, the THI and VASL/A scores worsened by 57% and 13%/14%, respectively. Using the hearing aid without CR treatment for 5 months no change in tinnitus symptoms was observed. However, after three months of CR treatment delivered through the hearing aids, the THI and VASL/A scores were reduced by 70% and 32%/32%, respectively.

  2. A review of stimuli-responsive polymers for smart textile applications

    Science.gov (United States)

    Hu, Jinlian; Meng, Harper; Li, Guoqiang; Ibekwe, Samuel I.

    2012-05-01

    Stimuli-responsive polymers (SRPs) are smart materials which can show noticeable changes in their properties with environmental stimulus variations. Novel functionalities can be delivered to textiles by integrating smart SRPs into them. SRPs inclusive of thermal-responsive polymers, moisture-responsive polymers, thermal-responsive hydrogels, pH-responsive hydrogels, and light-responsive polymers have been applied in textiles to improve or achieve textile smart functionalities. The functionalities include aesthetic appeal, comfort, textile soft display, smart controlled drug release, fantasy design with color changing, wound monitoring, smart wetting properties and protection against extreme variations in environmental conditions. In this review, the applications of SRPs in the textile and clothing sector are elucidated; the associated constraints in fabrication processes for textiles and their potential applications in the near future are discussed.

  3. Vibrotactile Sensitivity of the Head

    Science.gov (United States)

    2009-01-01

    1994; Watson and Pelli, 1983). Thresholds obtained using ZEST is based on a participant’s past performance and the use of this history makes it...America 1962, 34 (11), 1768–1773. Watson , A. B.; Pelli, D. G. QUEST: A Bayesian Adaptive Psychometric Method. Perception & Psychophysics 1983, 33...1 ARMY RSCH LABORATORY - HRED AWC FIELD ELEMENT AMSRD ARL HR MJ D DURBIN BLDG 4506 (DCD) RM 107 FT RUCKER AL 36362-5000 1 ARMY RSCH

  4. Glomerular input patterns in the mouse olfactory bulb evoked by retronasal odor stimuli.

    Science.gov (United States)

    Furudono, Yuichi; Cruz, Ginny; Lowe, Graeme

    2013-04-08

    Odorant stimuli can access the olfactory epithelium either orthonasally, by inhalation through the external nares, or retronasally by reverse airflow from the oral cavity. There is evidence that odors perceived through these two routes can differ in quality and intensity. We were curious whether such differences might potentially have a neural basis in the peripheral mechanisms of odor coding. To explore this possibility, we compared olfactory receptor input to glomeruli in the dorsal olfactory bulb evoked by orthonasal and retronasal stimulation. Maps of glomerular response were acquired by optical imaging of transgenic mice expressing synaptopHluorin (spH), a fluorescent reporter of presynaptic activity, in olfactory nerve terminals. We found that retronasally delivered odorants were able to activate inputs to multiple glomeruli in the dorsal olfactory bulb. The retronasal responses were smaller than orthonasal responses to odorants delivered at comparable concentrations and flow rates, and they displayed higher thresholds and right-shifted dose-response curves. Glomerular maps of orthonasal and retronasal responses were usually well overlapped, with fewer total numbers of glomeruli in retronasal maps. However, maps at threshold could be quite distinct with little overlap. Retronasal responses were also more narrowly tuned to homologous series of aliphatic odorants of varying carbon chain length, with longer chain, more hydrophobic compounds evoking little or no response at comparable vapor levels. Several features of retronasal olfaction are possibly referable to the observed properties of glomerular odorant responses. The finding that retronasal responses are weaker and sparser than orthonasal responses is consistent with psychophysical studies showing lower sensitivity for retronasal olfaction in threshold and suprathreshold tests. The similarity and overlap of orthonasal and retronasal odor maps at suprathreshold concentrations agrees with generally similar

  5. Prey capture behavior evoked by simple visual stimuli in larval zebrafish.

    Science.gov (United States)

    Bianco, Isaac H; Kampff, Adam R; Engert, Florian

    2011-01-01

    Understanding how the nervous system recognizes salient stimuli in the environment and selects and executes the appropriate behavioral responses is a fundamental question in systems neuroscience. To facilitate the neuroethological study of visually guided behavior in larval zebrafish, we developed "virtual reality" assays in which precisely controlled visual cues can be presented to larvae whilst their behavior is automatically monitored using machine vision algorithms. Freely swimming larvae responded to moving stimuli in a size-dependent manner: they directed multiple low amplitude orienting turns (∼20°) toward small moving spots (1°) but reacted to larger spots (10°) with high-amplitude aversive turns (∼60°). The tracking of small spots led us to examine how larvae respond to prey during hunting routines. By analyzing movie sequences of larvae hunting paramecia, we discovered that all prey capture routines commence with eye convergence and larvae maintain their eyes in a highly converged position for the duration of the prey-tracking and capture swim phases. We adapted our virtual reality assay to deliver artificial visual cues to partially restrained larvae and found that small moving spots evoked convergent eye movements and J-turns of the tail, which are defining features of natural hunting. We propose that eye convergence represents the engagement of a predatory mode of behavior in larval fish and serves to increase the region of binocular visual space to enable stereoscopic targeting of prey.

  6. Prey capture behaviour evoked by simple visual stimuli in larval zebrafish

    Directory of Open Access Journals (Sweden)

    Isaac Henry Bianco

    2011-12-01

    Full Text Available Understanding how the nervous system recognises salient stimuli in the environ- ment and selects and executes the appropriate behavioural responses is a fundamen- tal question in systems neuroscience. To facilitate the neuroethological study of visually-guided behaviour in larval zebrafish, we developed virtual reality assays in which precisely controlled visual cues can be presented to larvae whilst their behaviour is automatically monitored using machine-vision algorithms. Freely swimming larvae responded to moving stimuli in a size-dependent manner: they directed multiple low amplitude orienting turns (∼ 20◦ towards small moving spots (1◦ but reacted to larger spots (10◦ with high-amplitude aversive turns (∼ 60◦. The tracking of small spots led us to examine how larvae respond to prey during hunting routines. By analysing movie sequences of larvae hunting parame- cia, we discovered that all prey capture routines commence with eye convergence and larvae maintain their eyes in a highly converged position for the duration of the prey-tracking and capture swim phases. We adapted our virtual reality assay to deliver artificial visual cues to partially restrained larvae and found that small moving spots evoked convergent eye movements and J-turns of the tail, which are defining features of natural hunting. We propose that eye convergence represents the engagement of a predatory mode of behaviour in larval fish and serves to increase the region of binocular visual space to enable stereoscopic targeting of prey.

  7. Under pressure: adolescent substance users show exaggerated neural processing of aversive interoceptive stimuli

    NARCIS (Netherlands)

    Berk, L.; Stewart, J.L.; May, A.C.; Wiers, R.W.; Davenport, P.W.; Paulus, M.P.; Tapert, S.F.

    2015-01-01

    Aims: Adolescents with substance use disorders (SUD) exhibit hyposensitivity to pleasant internally generated (interoceptive) stimuli and hypersensitivity to external rewarding stimuli. It is unclear whether similar patterns exist for aversive interoceptive stimuli. We compared activation in the

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    Jiajin eYuan

    2015-04-01

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

  10. Rapid temporal recalibration to visuo-tactile stimuli.

    Science.gov (United States)

    Lange, Joachim; Kapala, Katharina; Krause, Holger; Baumgarten, Thomas J; Schnitzler, Alfons

    2017-11-15

    For a comprehensive understanding of the environment, the brain must constantly decide whether the incoming information originates from the same source and needs to be integrated into a coherent percept. This integration process is believed to be mediated by temporal integration windows. If presented with temporally asynchronous stimuli for a few minutes, the brain adapts to this new temporal relation by recalibrating the temporal integration windows. Such recalibration can occur even more rapidly after exposure to just a single trial of asynchronous stimulation. While rapid recalibration has been demonstrated for audio-visual stimuli, evidence for rapid recalibration of visuo-tactile stimuli is lacking. Here, we investigated rapid recalibration in the visuo-tactile domain. Subjects received visual and tactile stimuli with different stimulus onset asynchronies (SOA) and were asked to report whether the visuo-tactile stimuli were presented simultaneously. Our results demonstrate visuo-tactile rapid recalibration by revealing that subjects' simultaneity reports were modulated by the temporal order of stimulation in the preceding trial. This rapid recalibration effect, however, was only significant if the SOA in the preceding trial was smaller than 100 ms, while rapid recalibration could not be demonstrated for SOAs larger than 100 ms. Since rapid recalibration in the audio-visual domain has been demonstrated for SOAs larger than 100 ms, we propose that visuo-tactile recalibration works at shorter SOAs, and thus faster time scales than audio-visual rapid recalibration.

  11. 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.

  12. The stimuli drive the response: an fMRI study of youth processing adult or child emotional face stimuli.

    Science.gov (United States)

    Marusak, Hilary A; Carré, Justin M; Thomason, Moriah E

    2013-12-01

    Effective navigation of the social world relies on the correct interpretation of facial emotions. This may be particularly important in formative years. Critically, literature examining the emergence of face processing in youth (children and adolescents) has focused on the neural and behavioral correlates of processing adult faces, which are relationally different from youth participants, and whose facial expressions may convey different meaning than faces of their peers. During a functional magnetic resonance imaging (fMRI) scan, we compared concurrent neural and behavioral responses as youth (N=25) viewed validated, emotionally varied (i.e., anger, fear, happy, and neutral) adult and child face stimuli. We observed that participants made fewer errors when matching adult, compared to child, face stimuli, and that while similar brain regions were involved in processing both adult and child faces, activation in the face processing neural network was greater for adult than child faces. This was true across emotions, and also when comparing neutral adult versus neutral child faces. Additionally, a valence by stimuli-type effect was observed within the amygdala. That is, within adult face stimuli, negative and neutral face stimuli elicited the largest effects, whereas within child face stimuli, happy face stimuli elicited the largest amygdala effects. Thus, heightened engagement of the amygdala was observed for happy child and angry adult faces, which may reflect age-specific salience of select emotions in early life. This study provides evidence that the relational age of the perceived face influences neural processing in youth. © 2013 Elsevier Inc. All rights reserved.

  13. Delivering IT and eBusiness value

    CERN Document Server

    Willcocks, Leslie

    2001-01-01

    Delivering Business Value from IT' is focused on the evaluation issue in IT and how IT evaluation can proceed across the life-cycle of any IT investment and be linked positively to improving business performance. .Chapters 1,2 and 3 detail an approach to IT evaluation whilst chapters 4 and 5 build on these by showing two distinctive approaches to linking IT to business performance. The remaining three chapters deal with a range of evaluation issues emerging as important - specifically Internet evaluation, Y2K and beyond, EMU, quality outsourcing, infrastructure, role of benchmarking, and cost

  14. 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.

  15. Emotional conditioning to masked stimuli and modulation of visuospatial attention.

    Science.gov (United States)

    Beaver, John D; Mogg, Karin; Bradley, Brendan P

    2005-03-01

    Two studies investigated the effects of conditioning to masked stimuli on visuospatial attention. During the conditioning phase, masked snakes and spiders were paired with a burst of white noise, or paired with an innocuous tone, in the conditioned stimulus (CS)+ and CS- conditions, respectively. Attentional allocation to the CSs was then assessed with a visual probe task, in which the CSs were presented unmasked (Experiment 1) or both unmasked and masked (Experiment 2), together with fear-irrelevant control stimuli (flowers and mushrooms). In Experiment 1, participants preferentially allocated attention to CS+ relative to control stimuli. Experiment 2 suggested that this attentional bias depended on the perceived aversiveness of the unconditioned stimulus and did not require conscious recognition of the CSs during both acquisition and expression. Copyright 2005 APA, all rights reserved.

  16. 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.

  17. Stimuli-Responsive Cationic Hydrogels in Drug Delivery Applications

    Directory of Open Access Journals (Sweden)

    G. Roshan Deen

    2018-02-01

    Full Text Available Stimuli-responsive, smart, intelligent, or environmentally sensitive polymers respond to changes in external stimuli such as pH, temperature, ionic strength, surfactants, pressure, light, biomolecules, and magnetic field. These materials are developed in various network architectures such as block copolymers, crosslinked hydrogels, nanogels, inter-penetrating networks, and dendrimers. Stimuli-responsive cationic polymers and hydrogels are an interesting class of “smart” materials that respond reversibly to changes in external pH. These materials have the ability to swell extensively in solutions of acidic pH and de-swell or shrink in solutions of alkaline pH. This reversible swelling-shrinking property brought about by changes in external pH conditions makes these materials useful in a wide range of applications such as drug delivery systems and chemical sensors. This article focuses mainly on the properties of these interesting materials and their applications in drug delivery systems.

  18. Visual stimuli and written production of deaf signers.

    Science.gov (United States)

    Jacinto, Laís Alves; Ribeiro, Karen Barros; Soares, Aparecido José Couto; Cárnio, Maria Silvia

    2012-01-01

    To verify the interference of visual stimuli in written production of deaf signers with no complaints regarding reading and writing. The research group consisted of 12 students with education between the 4th and 5th grade of elementary school, with severe or profound sensorineural hearing loss, users of LIBRAS and with alphabetical writing level. The evaluation was performed with pictures in a logical sequence and an action picture. The analysis used the communicative competence criteria. There were no differences in the writing production of the subjects for both stimuli. In all texts there was no title and punctuation, verbs were in the infinitive mode, there was lack of cohesive links and inclusion of created words. The different visual stimuli did not affect the production of texts.

  19. Exposure to virtual social stimuli modulates subjective pain reports.

    Science.gov (United States)

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

    2014-01-01

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

  20. Generalization of Extinguished Fear to Untreated Fear Stimuli after Exposure.

    Science.gov (United States)

    Preusser, Friederike; Margraf, Jürgen; Zlomuzica, Armin

    2017-12-01

    Exposure therapy is highly effective in treating excessive fear related to specific objects and/or situations. However, patients with anxiety disorders often display a generalization of fear responses toward conceptually and perceptually related stimuli and situations. It is unclear whether the beneficial effects of exposure on fear reduction toward treated fear stimuli can extend to untreated fear stimuli. Here, we investigated whether basic principles of extinction generalization apply to exposure. Spider-phobic participants were randomly assigned to either two sessions of exposure treatment (n=23) with spiders or no-treatment (n=24). Prior to and after treatment, behavioral approach tests (BATs) were conducted to examine avoidance, fear and disgust responses toward the treated phobic stimulus (spider as the extinction stimulus). Likewise, BATs with the untreated fear stimulus (cockroach) were conducted to dissect the generalization of treatment effects. Treatment was highly effective in increasing approach behavior toward both treated and untreated fear stimuli. Generalization of treatment effects were evident on the behavioral (approach distance during the BAT), subjective (fear levels during the BAT) and psychophysiological level (heart rate during the BAT). However, a stronger decline in disgust was only evident for the treated fear stimulus. Notably, the herein attained generalization effects were not context-dependent. Hence, exposure therapy for spider phobia was effective in reducing fear of untreated stimuli which share common fear-evoking characteristics with spiders but were never presented during the respective exposure treatment. These findings provide clinical evidence for extinction generalization across different fear-evoking stimuli mediated via exposure.

  1. 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.

  2. Cell microcarriers and microcapsules of stimuli-responsive polymers.

    Science.gov (United States)

    Brun-Graeppi, Amanda K Andriola Silva; Richard, Cyrille; Bessodes, Michel; Scherman, Daniel; Merten, Otto-Wilhelm

    2011-02-10

    Cell microcarriers and microcapsules have presented a wide range of potential applications. This article overviews their role in biotechnology with focus on the progress accomplished using stimuli-responsive polymers. Key properties of cell microcarriers and microcapsules are identified, followed by a description of the chemistry and gel formation mechanism of some of the stimuli-responsive polymers used to design them. Production methods are introduced and characterization techniques for evaluating such microsystems are equally presented. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Cognitive robotic system for learning of complex visual stimuli

    Science.gov (United States)

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

    2013-05-01

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

  4. 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...

  5. DESIGNS MATTER: Delivering Information Sources for Tourism

    Directory of Open Access Journals (Sweden)

    Margie A. Nolasco

    2016-11-01

    Full Text Available Tourism has benefits not just for travelers, but also to the local economy. Since, Bicol Region has natural and cultural attractions; it is a potential travel destination in the country. Technology in delivering information sources played vital role for the success of the tourism industry in the Region. This allows travel enthusiasts to get more information about various tourist attractions. This paper analyzes the effectiveness of delivering information sources such as web advertisement and desktop publishing for tourist promotion in the Bicol Region. Specifically, it determined the status of tourism, and identified common forms of promotions for tourism development. The study adopted mixed method of research. This method was utilized to confirm and validate findings. Interviews and focus group discussions were used to gather data from the respondents of the selected Local Government Units, Department of Tourism, Travel Agencies and Hotel Agents in the Region. Based on the findings, of the total foreign visitors in the country, only 9.14% visited Bicol Region in 2014. That is why, domestic tourist showed high percentage against foreign visitors with 25.7%. Brochures with EZ maps as most commonly used desktop publishing materials and websites and social media for web advertisement. Thus, there is a need to reevaluate promotional activities by the DOT and other agencies. Adoption suggestive features for creative desktop publishing materials and web services should be considered to increase tourist visitors in the Region.

  6. Pupil size as related to interest value of visual stimuli.

    Science.gov (United States)

    HESS, E H; POLT, J M

    1960-08-05

    Increases in the size of the pupil of the eye have been found to accompany the viewing of emotionally toned or interesting visual stimuli. A technique for recording such changes has been developed, and preliminary results with cats and human beings are reported with attention being given to differences between the sexes in response to particular types of material.

  7. 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.

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

    Science.gov (United States)

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

    2008-10-20

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

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

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    ), 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......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...... to punctate stimuli was assessed with a rigid von Frey hair (462 mN). The heat pain responses to 45 degrees C in 5 s (3.75 cm2) were tested in the area just outside the burn, where the subjects developed secondary hyperalgesia, and on the lateral crus where no subject developed secondary hyperalgesia (control...

  10. External stimuli response on a novel chitosan hydrogel crosslinked ...

    Indian Academy of Sciences (India)

    The influence of external stimuli such as pH, temperature, and ionic strength of the swelling media on equilibrium swelling properties has been observed. Hydrogels showed a typical pH and temperature responsive behaviour such as low pH and high temperature has maximum swelling while high pH and low temperature ...

  11. P3a from auditory white noise stimuli.

    Science.gov (United States)

    Combs, Lindsey A; Polich, John

    2006-05-01

    P3a and P3b event-related brain potentials (ERPs) were elicited with an auditory 3-stimulus (target, distracter, standard) paradigm in which subjects responded only to the target. Distracter stimuli consisted of white noise, novel sounds, or a high frequency tone, with stimulus characteristics perceptually controlled. Task difficulty was varied as easy and hard by changing the pitch difference between the target and standard stimuli. Error rate was greater and response time longer for the hard task. P3a distracter amplitude was largest for the white noise and novel stimuli, with maximum amplitude over the central recording sites, and larger for the hard discrimination task. P3b target amplitude was unaffected by distracter type, maximum over the parietal recording sites, and smaller and later for the hard task. The findings indicate that white noise stimuli can produce reliable P3a components. White noise can be useful for clinical P3a applications, as it removes the variability of stimulus novelty.

  12. 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. Copyright © 2015 the authors 0270-6474/15/354179-11$15.00/0.

  13. 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

  14. Vestibular rehabilitation with visual stimuli in peripheral vestibular disorders.

    Science.gov (United States)

    Manso, Andréa; Ganança, Mauricio Malavasi; Caovilla, Heloisa Helena

    2016-01-01

    Visual stimuli can induce vestibular adaptation and recovery of body balance. To verify the effect of visual stimuli by digital images on vestibular and body balance rehabilitation of peripheral vestibular disorders. 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. 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. 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. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  15. 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.

  16. Challenging Cognitive Control by Mirrored Stimuli in Working Memory Matching

    Directory of Open Access Journals (Sweden)

    Maria Wirth

    2017-04-01

    Full Text Available Cognitive conflict has often been investigated by placing automatic processing originating from learned associations in competition with instructed task demands. Here we explore whether mirror generalization as a congenital mechanism can be employed to create cognitive conflict. Past research suggests that the visual system automatically generates an invariant representation of visual objects and their mirrored counterparts (i.e., mirror generalization, and especially so for lateral reversals (e.g., a cup seen from the left side vs. right side. Prior work suggests that mirror generalization can be reduced or even overcome by learning (i.e., for those visual objects for which it is not appropriate, such as letters d and b. We, therefore, minimized prior practice on resolving conflicts involving mirror generalization by using kanji stimuli as non-verbal and unfamiliar material. In a 1-back task, participants had to check a stream of kanji stimuli for identical repetitions and avoid miss-categorizing mirror reversed stimuli as exact repetitions. Consistent with previous work, lateral reversals led to profound slowing of reaction times and lower accuracy in Experiment 1. Yet, different from previous reports suggesting that lateral reversals lead to stronger conflict, similar slowing for vertical and horizontal mirror transformations was observed in Experiment 2. Taken together, the results suggest that transformations of visual stimuli can be employed to challenge cognitive control in the 1-back task.

  17. Emergence of Intraverbal Responding Following Tact Instruction with Compound Stimuli

    Science.gov (United States)

    Devine, Bailey; Carp, Charlotte L.; Hiett, Kiley A.; Petursdottir, Anna Ingeborg

    2016-01-01

    Effective intraverbal responding often requires control by multiple elements of a verbal stimulus. The purpose of this study was to examine the emergence of such intraverbal relations following tact instruction with compound stimuli and to analyze any resulting error patterns. Participants were seven typically developing children between 3 and…

  18. Exposure to Virtual Social Stimuli Modulates Subjective Pain Reports

    Directory of Open Access Journals (Sweden)

    Jacob M Vigil

    2014-01-01

    Full Text Available BACKGROUND: Contextual factors, including the gender of researchers, influence experimental and patient pain reports. It is currently not known how social stimuli influence pain percepts, nor which types of sensory modalities of communication, such as auditory, visual or olfactory cues associated with person perception and gender processing, produce these effects.

  19. 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…

  20. 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…

  1. Music influences ratings of the affect of visual stimuli

    NARCIS (Netherlands)

    Hanser, W.E.; Mark, R.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

  2. Combining Technologies to Deliver Distance Education

    Directory of Open Access Journals (Sweden)

    Vicki Freeman

    1999-01-01

    Full Text Available In 1997 a Health Resources and Services Administration (HRSA grant was awarded to the Department of Clinical Laboratory Sciences (CLS at The University of Texas Medical Branch - Galveston (UTMB for support of the Laboratory Education and Advancement Project (LEAP. The project entailed three primary objectives, targeting laboratory practitioners in rural and medically underserved areas of Texas for delivering a bachelor's degree, laboratory-intensive course of study via distance education. Several delivery mechanisms were utilized and evaluated for their effectiveness and friendliness to both the faculty and students. The authors discuss and describe the mechanisms utilized for delivery of courses, the advantages and disadvantages encountered with each mechanism, and subjective evaluation of the effectiveness of the courses. Also discussed are the lessons learned and plans for future development.

  3. Intranasal formulations: promising strategy to deliver vaccines.

    Science.gov (United States)

    Riese, Peggy; Sakthivel, Priya; Trittel, Stephanie; Guzmán, Carlos A

    2014-10-01

    The emergence of new diseases and the lack of efficient vaccines against numerous non-treatable pathogens require the development of novel vaccination strategies. To date, only a few mucosal vaccines have been approved for humans. This was in part due to i) the use of live attenuated vaccines, which are not suitable for certain groups of individuals, ii) safety concerns derived from implementation in humans of some mucosal vaccines, iii) the poor stability, absorption and immunogenicity of antigens delivered by the mucosal route and iv) the limited number of available technologies to overcome the bottlenecks associated with mucosal antigen delivery. Recent advances make feasible the development of efficacious mucosal vaccines with adequate safety profile. Thus, currently intranasal vaccines represent an attractive and valid alternative to conventional vaccines. The present review is focused on the potentials and limitations of market-approved intranasal vaccines and promising candidates undergoing clinical investigations. Furthermore, emerging strategies to overcome main bottlenecks including efficient breaching of the mucosal barrier and safety concerns by implementation of new adjuvants and delivery systems are discussed. The rational design of intranasal vaccines requires an in-depth understanding of the anatomic, physicochemical and barrier properties of the nasal mucosa, as well as the molecular mechanisms governing the activation of the local innate and adaptive immune system. This would provide the critical knowledge to establish effective approaches to deliver vaccine antigens across the mucosal barrier, supporting the stimulation of a long-lasting protective response at both mucosal and systemic levels. Current developments in the area of adjuvants, nanotechnologies and mucosal immunology, together with the identification of surface receptors that can be exploited for cell targeting and manipulating their physiological properties, will become instrumental

  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. Extrastriate body area underlies aesthetic evaluation of body stimuli.

    Science.gov (United States)

    Calvo-Merino, B; Urgesi, C; Orgs, G; Aglioti, S M; Haggard, P

    2010-07-01

    Humans appear to be the only animals to have developed the practice and culture of art. This practice presumably relies on special processing circuits within the human brain associated with a distinct subjective experience, termed aesthetic experience, and preferentially evoked by artistic stimuli. We assume that positive or negative aesthetic judgments are an important function of neuroaesthetic circuits. The localisation of these circuits in the brain remains unclear, though neuroimaging studies have suggested several possible neural correlates of aesthetic preference. We applied repetitive transcranial magnetic stimulation (rTMS) over candidate brain areas to disrupt aesthetic processing while healthy volunteers made aesthetic preference judgments between pairs of dance postures, or control non-body stimuli. Based on evidence from visual body perception studies, we targeted the ventral premotor cortex (vPMC) and extrastriate body area (EBA), in the left and right hemispheres. rTMS over EBA reduced aesthetic sensitivity for body stimuli relative to rTMS over vPMC, while no such difference was found for non-body stimuli. We interpret our results within the framework of dual routes for visual body processing. rTMS over either EBA or vPMC reduced the contributions of the stimulated area to body processing, leaving processing more reliant on the unaffected route. Disruption of EBA reduces the local processing of the stimuli and reduced observers' aesthetic sensitivity. Conversely, disruption of the global route via vPMC increased the relative contribution of the local route via EBA and thus increased aesthetic sensitivity. In this way, we suggest a complementary contribution of both local and global routes to aesthetic processing.

  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. Brain responses in evaluating feedback stimuli with a social dimension

    Directory of Open Access Journals (Sweden)

    Yuan eZhang

    2012-02-01

    Full Text Available Previous studies on outcome evaluation and performance monitoring using gambling or simple cognitive tasks have identified two components of event-related potentials (ERPs that are particularly relevant to the neural responses to decision outcome. The feedback-related negativity (FRN, typically occurring 200-300 ms post-onset of feedback stimuli, encodes mainly the valence of outcome while the P300, which is the most positive peak between 200-600 ms, is found to be related to various aspects of outcome evaluation. This study investigated the extent which neural correlates of outcome evaluation involving complex feedback stimuli (i.e., female faces are similar to those revealed for simplex feedback. We asked participants to judge the attractiveness of blurred faces and then showed them unblurred faces as (implicit feedback of their performance. The FRN effect can be identified by the ERP waveforms, albeit in a delayed 300-380 ms time window, with faces inconsistent with the initial judgment eliciting more negative-going responses than faces consistent with the judgment. However, the ERP waveforms did not show the typical pattern of P300 responses. With the principal component analysis (PCA, a clear pattern of P300 effects were revealed, with the P300 being more positive to faces consistent with the initial judgment than to faces inconsistent with the judgment and more positive to attractive faces than to unattractive ones. The feedback consistency effect on either the FRN or the P300 was unaffected by the attractiveness of the feedback faces. These findings suggest that brain responses involved in processing complex feedback stimuli with a social dimension are generally similar to those involved in processing simplex feedback stimuli in gambling or cognitive tasks, although appropriate means of data analysis are needed to reveal the typical ERP effects that may have been masked by sophisticated cognitive (and emotional processes for complex

  8. Design Environment for Novel Vertical Lift Vehicles: DELIVER

    Science.gov (United States)

    Theodore, Colin

    2016-01-01

    This is a 20 minute presentation discussing the DELIVER vision. DELIVER is part of the ARMD Transformative Aeronautics Concepts Program, particularly the Convergent Aeronautics Solutions Project. The presentation covers the DELIVER vision, transforming markets, conceptual design process, challenges addressed, technical content, and FY2016 key activities.

  9. CORTICAL RESPONSES TO SALIENT NOCICEPTIVE AND NOT NOCICEPTIVE STIMULI IN VEGETATIVE AND MINIMAL CONSCIOUS STATE

    Directory of Open Access Journals (Sweden)

    MARINA eDE TOMMASO

    2015-01-01

    Full Text Available Aims Questions regarding perception of pain in non-communicating patients and the management of pain continue to raise controversy both at a clinical and ethical level. The aim of this study was to examine the cortical response to salient multimodal visual, acoustic, somatosensory electric non nociceptive and nociceptive laser stimuli and their correlation with the clinical evaluation.Methods: Five Vegetative State (VS, 4 Minimally Conscious State (MCS patients and 11 age- and sex-matched controls were examined. Evoked responses were obtained by 64 scalp electrodes, while delivering auditory, visual, non-noxious electrical and noxious laser stimulation, which were randomly presented every 10 sec. Laser, somatosensory, auditory and visual evoked responses were identified as a negative-positive (N2-P2 vertex complex in the 500 msec post-stimulus time. We used Nociception Coma Scale-Revised (NCS-R and Coma Recovery Scale (CRS-R for clinical evaluation of pain perception and consciousness impairment.Results: The laser evoked potentials (LEPs were recognizable in all cases. Only one MCS patient showed a reliable cortical response to all the employed stimulus modalities. One VS patient did not present cortical responses to any other stimulus modality. In the remaining participants, auditory, visual and electrical related potentials were inconstantly present. Significant N2 and P2 latency prolongation occurred in both VS and MCS patients. The presence of a reliable cortical response to auditory, visual and electric stimuli was able to correctly classify VS and MCS patients with 90% accuracy. Laser P2 and N2 amplitudes were not correlated with the CRS-R and NCS-R scores, while auditory and electric related potentials amplitude were associated with the motor response to pain and consciousness recovery. Discussion: pain arousal may be a primary function also in vegetative state patients while the relevance of other stimulus modalities may indicate the

  10. Anticipatory VOR suppression induced by visual and nonvisual stimuli in humans.

    Science.gov (United States)

    Barnes, G R; Paige, G D

    2004-09-01

    We compared the predictive behavior of smooth pursuit (SP) and suppression of the vestibuloocular reflex (VOR) in humans by examining anticipatory smooth eye movements, a phenomenon that arises after repeated presentations of sudden target movement preceded by an auditory warning cue. We investigated whether anticipatory smooth eye movements also occur prior to cued head motion, particularly when subjects expect interaction between the VOR and either real or imagined head-fixed targets. Subjects were presented with horizontal motion stimuli consisting of a visual target alone (SP), head motion in darkness (VOR), or head motion in the presence of a real or imagined head-fixed target (HFT and IHFT, respectively). Stimulus sequences were delivered as single cycles of a velocity sinusoid (frequency: 0.5 or 1.0 Hz) that were either cued (a sound cue 400 ms earlier) or noncued. For SP, anticipatory smooth eye movements developed over repeated trials in the cued, but not the noncued, condition. In the VOR condition, no such anticipatory eye movements were observed even when cued. In contrast, anticipatory responses were observed under cued, but not noncued, HFT and IHFT conditions, as for SP. Anticipatory HFT responses increased in proportion to the velocity of preceding stimuli. In general, anticipatory gaze responses were similar in cued SP, HFT, and IHFT conditions and were appropriate for expected target motion in space. Anticipatory responses may represent the output of a central mechanism for smooth-eye-movement generation that operates during predictive SP as well as VOR modulations that are linked with SP even in the absence of real visual targets.

  11. Delivering flavonoids into solid tumors using nanotechnologies.

    Science.gov (United States)

    Wang, Shengpeng; Zhang, Jinming; Chen, Meiwan; Wang, Yitao

    2013-10-01

    Long-term epidemiological studies have demonstrated that regular ingestion of flavonoids contained in dietary sources is associated with a reduced risk for many chronic diseases including cancer. However, although flavonoids are largely consumed in the diet and high concentrations may exist in the intestine after oral administration, the plasma/tissue concentrations of flavonoids are lower than their effective therapeutic doses due to poor bioavailability, resulting in the limited efficacy of flavonoids in various clinical studies. Therefore, the application of nanotechnology to deliver flavonoids to tumor sites has received considerable attention in recent years. In this review, after a general review of the potential benefits of flavonoids in cancer therapy and several key factors affecting their bioavailability, the current efforts in improving the delivery efficacy of promising candidates that are particularly important in the human diet, namely quercetin, epigallocatechin-3-gallate (EGCG) and genistein were focused on. Finally, the challenges of developing flavonoid delivery systems that improve flavonoid bioavailability and their anticancer therapy potentials were summarized. The design of suitable molecular carriers for flavonoids is an area of research that is in rapid progress. A large number of unheeded promising favonoids are suffering from poor in vivo parameters, their potential benefits deserves further research. Furthermore, more effort should be placed on developing active targeting systems, evaluating the efficacy and toxicity of novel flavonoid delivery systems through small and large scale clinical trials.

  12. Delivering new physics at impressive speed

    CERN Multimedia

    2010-01-01

    The speed with which the heavy ion run at the LHC is delivering new physics is impressive not only for the insights it is bringing to the early Universe, but also for the clear demonstration it gives of the value of competition and complementarity between the experiments.   ALICE was the first off the mark to publish papers from the ion run, as you’d expect from the LHC’s dedicated ion experiment, but results emerging from ATLAS and CMS are bringing new understanding in their own right. Each collaboration’s result plays to the strengths of its detector, and it is by taking all the results together that our knowledge advances. The creation, observation and understanding of the hot dense matter that would have existed in the early Universe, normally known as Quark Gluon Plasma (QGP), is complex science and one of the ion programme’s key goals. Many signals for QGP exist, and like pieces of a puzzle, we must assemble all of them to get the full picture. At th...

  13. Polymers for delivering peptides and proteins.

    Science.gov (United States)

    Burnham, N L

    1994-01-15

    The use of polymers for delivering peptide and protein drugs is described. Soluble-polymer technology attempts to bind a polymer to all sites on therapeutic protein molecules that cause the body to recognize the molecules as foreign. Goals include a stable linkage, water solubility, low immunogenicity, prolonged half-life, and intact biological activity. Polyethylene glycol (PEG)-adenosine deaminase (ADA), or pegademase bovine, has FDA-approved labeling as replacement therapy for ADA deficiency in patients with severe combined immunodeficiency disease who are not suitable candidates for bone marrow transplantation. Pegademase bovine reverses the toxic accumulation of adenosine and deoxyadenosine in adenosine deaminase-deficient cells, restoring the immune system. PEG-asparaginase (pegaspargase) has shown promise in patients with acute lymphocytic leukemia; allergic reactions have been minimal. Animal studies suggest that superoxide dismutase has potential use in conditions in which the body's ability to remove oxygen free radicals is reduced, such as burns and myocardial infarction; coupling with PEG may greatly increase the protein's half-life. Other PEG-conjugated proteins under investigation include PEG-catalase, PEG-uricase, PEG-honeybee venom, PEG-hemoglobin, and PEG-modified ragweed pollen extract. Dextran, albumin, DL-amino acids, and polyvinyl pyrrolidone have also been studied as protein carriers; most of the products created thus far have not shown much promise. The coupling of polymers to proteins has yielded protein drugs with intact biological activity and reduced immunogenicity, but much remains to be learned about this technology.

  14. Where should noninvasive ventilation be delivered?

    Science.gov (United States)

    Hill, Nicholas S

    2009-01-01

    Noninvasive ventilation (NIV) has assumed an important role in the management of certain types of respiratory failure in acute-care hospitals. However, the optimal location for NIV has been a matter of debate. Some have argued that all patients begun on NIV in the acute-care setting should go to an intensive care unit (ICU), but this is impractical because ICU beds are often unavailable, and it may not be a sensible use of resources. Also, relatively few studies have examined the question of location for NIV. One problem is that various units' capabilities to deliver NIV differ substantially, even in the same hospital. Choosing the appropriate environment for NIV requires consideration of the patient's need for monitoring, the monitoring capabilities of the unit, including both technical and personnel resources (nursing and respiratory therapy), and the staff's skill and experience. In some hospitals NIV is begun most often in the emergency department, but is most often managed in an ICU. Step-down units are often good locations for NIV, but many institutions do not have step-down units. With ICU beds at a premium, many hospitals are forced to manage some NIV patients on general wards, which can be safely done with more stable patients if the ward is suitably monitored and experienced. When deciding where to locate the patient, clinicians must be familiar with the capabilities of the units in their facility and try to match the patient's need for monitoring and the unit's capabilities.

  15. Chords and harmonies in mixed optical and acoustical stimuli

    Science.gov (United States)

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

    2014-09-01

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

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

    Science.gov (United States)

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

    2010-05-01

    It is often assumed that attention is automatically allocated to stimuli relevant to one's actual goals. However, the existing evidence for this idea is limited in several ways. We investigated whether words relevant to a person's current goal influence the orienting of attention even when an intention to attend to the goal-relevant stimuli is not present. In two experiments, participants performed a modified spatial cueing paradigm combined with a second task that induced a goal. The results of the experiments showed that the induced goal led to the orientation of attention to goal-relevant words in the spatial cueing task. This effect was not found for words semantically related to the goal-relevant words. The results provide evidence for motivational accounts of attention, which state that the automatic allocation of attention is guided by the current goals of a person. Copyright 2009 Elsevier B.V. All rights reserved.

  17. Stimuli Responsive Poly(Vinyl Caprolactam Gels for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Kummara Madhusudana Rao

    2016-01-01

    Full Text Available Poly(vinyl caprolactam (PNVCL is one of the most important thermoresponsive polymers because it is similar to poly(N-isopropyl acrylamide. PNVCL precipitates from aqueous solutions in a physiological temperature range (32–34 °C. The use of PNVCL instead of PNIPAM is considered advantageous because of the assumed lower toxicity of PNVCL. PNVCL copolymer gels are sensitive to external stimuli, such as temperature and pH; which gives them a wide range of biomedical applications and consequently attracts considerable scientific interest. This review focuses on the recent studies on PNVCL-based stimuli responsive three dimensional hydrogels (macro, micro, and nano for biomedical applications. This review also covers the future outlooks of PNVCL-based gels for biomedical applications, particularly in the drug delivery field.

  18. Afferent activity to necklace glomeruli is dependent on external stimuli

    Directory of Open Access Journals (Sweden)

    Munger Steven D

    2009-03-01

    Full Text Available Abstract Background The main olfactory epithelium (MOE is a complex organ containing several functionally distinct subpopulations of sensory neurons. One such subpopulation is distinguished by its expression of the guanylyl cyclase GC-D. The axons of GC-D-expressing (GC-D+ neurons innervate 9–15 "necklace" glomeruli encircling the caudal main olfactory bulb (MOB. Chemosensory stimuli for GC-D+ neurons include two natriuretic peptides, uroguanylin and guanylin, and CO2. However, the biologically-relevant source of these chemostimuli is unclear: uroguanylin is both excreted in urine, a rich source of olfactory stimuli for rodents, and expressed in human nasal epithelium; CO2 is present in both inspired and expired air. Findings To determine whether the principal source of chemostimuli for GC-D+ neurons is external or internal to the nose, we assessed the consequences of removing external chemostimuli for afferent activity to the necklace glomeruli. To do so, we performed unilateral naris occlusions in Gucy2d-Mapt-lacZ +/- mice [which express a β-galactosidase (β-gal reporter specifically in GC-D+ neurons] followed by immunohistochemistry for β-gal and a glomerular marker of afferent activity, tyrosine hydroxylase (TH. We observed a dramatic decrease in TH immunostaining, consistent with reduced or absent afferent activity, in both necklace and non-necklace glomeruli ipsilateral to the occluded naris. Conclusion Like other MOB glomeruli, necklace glomeruli exhibit a large decrease in afferent activity upon removal of external stimuli. Thus, we conclude that activity in GC-D+ neurons, which specifically innervate necklace glomeruli, is not dependent on internal stimuli. Instead, GC-D+ neurons, like other OSNs in the MOE, primarily sense the external world.

  19. 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.

  20. Investigating Electrophysiology for Measuring Emotions Triggered by Audio Stimuli

    OpenAIRE

    Mazza, Filippo; Perreira Da Silva, Matthieu; Le Callet, Patrick

    2013-01-01

    International audience; Multimedia quality evaluation recently started to take into account also analysis of emotional response to audio- visual stimuli. This is especially true for quality of experience evaluation. Self-assessed affective reports are commonly used for this purpose. Nevertheless, measuring emotions via physiological measurement might be also considered as it could limit the effects of cognitive bias due to self-report following the rule that your body cannot lie. In this pape...

  1. Stimuli-responsive hydrogels cross-linked by magnetic nanoparticles

    OpenAIRE

    Ilg Patrick

    2013-01-01

    Embedding magnetic nanoparticles into soft host media offers the opportunity to externally control material properties via a magnetic field. Choosing a hydrogel as host medium allows to modify not only the elastic properties but also the degree of swelling of the gel and the shape changes of the sample. Hydrogels where magnetic nanoparticles serve as the only crosslinking reagent of the network are a promising new class of such stimuli responsive gels. The well defined magneto mechanical coup...

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

    OpenAIRE

    Martina Starc; Grega Repovš

    2016-01-01

    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 dis...

  3. 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. .

  4. Music Influences Ratings of the Affect of Visual Stimuli

    OpenAIRE

    Hanser, Waldie E.; 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...

  5. 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.

  6. Stability of Pain Measures in a Different Stimuli Context

    OpenAIRE

    Modić Stanke, Koraljka

    2017-01-01

    Pain in any context is always associated with high inter- and intra-individual variability. There are several pain-inducement methods and numerous pain measurement methods at researchers’ disposal in experimental settings; since none of them is without limitations, the increasing number of researchers decides upon a multi-method approach. In doing so, clarity and unambiguity of the results may vary – depending on the reliability of the certain method in a specific stimuli context. The ai...

  7. Oscillations in the Visual Response to Pulsed Stimuli,

    Science.gov (United States)

    1982-06-01

    only 7 Hz. Also, Fukuda (1977) presented flickering photic stimuli and asked observ- ers to adjust the frequency of an audio flutter stimulus until...perceptible time-interval between two flashes of light. Psychological Review. 22:226-250. Fukuda , T. 1977. Subjective frequency in flicker perception...Monmouth, NJ 07703 (1) Commander US Army Training and Doctrine Command Commander/Di rector ATTN: ATCD US Army Combat Surveillance & Fort Monroe, VA 23651

  8. Investigating vision in schizophrenia through responses to humorous stimuli

    OpenAIRE

    Tschacher, Wolfgang; Genner, Ruth; Bryjová, Jana; Schaller, Elisabeth; Samson, Andrea C.

    2015-01-01

    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...

  9. Two-stimuli manipulation of a biological motor

    Directory of Open Access Journals (Sweden)

    Kemnitz Klaus

    2009-05-01

    Full Text Available Abstract F1-ATPase is an enzyme acting as a rotary nano-motor. During catalysis subunits of this enzyme complex rotate relative to other parts of the enzyme. Here we demonstrate that the combination of two input stimuli causes stop of motor rotation. Application of either individual stimulus did not significantly influence motor motion. These findings may contribute to the development of logic gates using single biological motor molecules.

  10. 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

  11. Saccadic Tracking with Random Walk (brownian Motion) Stimuli.

    Science.gov (United States)

    Horner, Douglas Gordon

    This study was designed to evaluate the saccadic system's response to continuously presented random walk (Brownian motion) stimuli. Our goals were: (1) to examine how closely timed consecutive saccades interact; and (2) to estimate the response modification time for the new position of the stimulus to give an estimate of integration and decision delays. Horizontal eye movements resulting from rapid continuous random target movements were recorded. Step amplitudes of 1.5 and 3.0 degrees were alternated between single- and rapid double-step movements every 200 to 400 msec. From these random multiple stimulus step sequences, saccadic responses to single 3.0 degree step stimuli were collected for subjects to evaluate interactions of consecutive saccades. The results showed that: (1) subjects are capable of making independent goal directed saccades with intersaccadic intervals as short as 50 msec, and (2) subjects had individual biases in the direction of the successive saccades. The main interaction between saccades was related to the spatial error of the preceding saccade combining with the new stimulus step to yield the new error signal for the next saccade. The magnitude of the new retinal error signal was reflected in the latency of the following saccade. To evaluate the decision period of the saccadic system, the single-step responses were used as templates to assess the modification times for staircase, pulse under -return and pulse over-return double-step stimuli. The responses were organized by whether consecutive saccades continued in the same direction or in the opposite direction. The results on the modification times indicate saccadic responses are directed to the new stimulus 85 to 90 msec after the new position of the stimulus. This modification time was independent of stimuli and preferred direction of responses. The 85-90 msec modification delay is used to estimate the time interval needed to program the next saccade.

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

    Directory of Open Access Journals (Sweden)

    Marcello Siniscalchi

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

  13. Purpose in Life Predicts Better Emotional Recovery from Negative Stimuli

    Science.gov (United States)

    Schaefer, Stacey M.; Morozink Boylan, Jennifer; van Reekum, Carien M.; Lapate, Regina C.; Norris, Catherine J.; Ryff, Carol D.; Davidson, Richard J.

    2013-01-01

    Purpose in life predicts both health and longevity suggesting that the ability to find meaning from life’s experiences, especially when confronting life’s challenges, may be a mechanism underlying resilience. Having purpose in life may motivate reframing stressful situations to deal with them more productively, thereby facilitating recovery from stress and trauma. In turn, enhanced ability to recover from negative events may allow a person to achieve or maintain a feeling of greater purpose in life over time. In a large sample of adults (aged 36-84 years) from the MIDUS study (Midlife in the U.S., http://www.midus.wisc.edu/), we tested whether purpose in life was associated with better emotional recovery following exposure to negative picture stimuli indexed by the magnitude of the eyeblink startle reflex (EBR), a measure sensitive to emotional state. We differentiated between initial emotional reactivity (during stimulus presentation) and emotional recovery (occurring after stimulus offset). Greater purpose in life, assessed over two years prior, predicted better recovery from negative stimuli indexed by a smaller eyeblink after negative pictures offset, even after controlling for initial reactivity to the stimuli during the picture presentation, gender, age, trait affect, and other well-being dimensions. These data suggest a proximal mechanism by which purpose in life may afford protection from negative events and confer resilience is through enhanced automatic emotion regulation after negative emotional provocation. PMID:24236176

  14. 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.

  15. Purpose in life predicts better emotional recovery from negative stimuli.

    Science.gov (United States)

    Schaefer, Stacey M; Morozink Boylan, Jennifer; van Reekum, Carien M; Lapate, Regina C; Norris, Catherine J; Ryff, Carol D; Davidson, Richard J

    2013-01-01

    Purpose in life predicts both health and longevity suggesting that the ability to find meaning from life's experiences, especially when confronting life's challenges, may be a mechanism underlying resilience. Having purpose in life may motivate reframing stressful situations to deal with them more productively, thereby facilitating recovery from stress and trauma. In turn, enhanced ability to recover from negative events may allow a person to achieve or maintain a feeling of greater purpose in life over time. In a large sample of adults (aged 36-84 years) from the MIDUS study (Midlife in the U.S., http://www.midus.wisc.edu/), we tested whether purpose in life was associated with better emotional recovery following exposure to negative picture stimuli indexed by the magnitude of the eyeblink startle reflex (EBR), a measure sensitive to emotional state. We differentiated between initial emotional reactivity (during stimulus presentation) and emotional recovery (occurring after stimulus offset). Greater purpose in life, assessed over two years prior, predicted better recovery from negative stimuli indexed by a smaller eyeblink after negative pictures offset, even after controlling for initial reactivity to the stimuli during the picture presentation, gender, age, trait affect, and other well-being dimensions. These data suggest a proximal mechanism by which purpose in life may afford protection from negative events and confer resilience is through enhanced automatic emotion regulation after negative emotional provocation.

  16. The Commonality of Loss Aversion across Procedures and Stimuli.

    Directory of Open Access Journals (Sweden)

    Sang Lee

    Full Text Available Individuals tend to give losses approximately 2-fold the weight that they give gains. Such approximations of loss aversion (LA are almost always measured in the stimulus domain of money, rather than objects or pictures. Recent work on preference-based decision-making with a schedule-less keypress task (relative preference theory, RPT has provided a mathematical formulation for LA similar to that in prospect theory (PT, but makes no parametric assumptions in the computation of LA, uses a variable tied to communication theory (i.e., the Shannon entropy or information, and works readily with non-monetary stimuli. We evaluated if these distinct frameworks described similar LA in healthy subjects, and found that LA during the anticipation phase of the PT-based task correlated significantly with LA related to the RPT-based task. Given the ease with which non-monetary stimuli can be used on the Internet, or in animal studies, these findings open an extensive range of applications for the study of loss aversion. Furthermore, the emergence of methodology that can be used to measure preference for both social stimuli and money brings a common framework to the evaluation of preference in both social psychology and behavioral economics.

  17. Purpose in life predicts better emotional recovery from negative stimuli.

    Directory of Open Access Journals (Sweden)

    Stacey M Schaefer

    Full Text Available Purpose in life predicts both health and longevity suggesting that the ability to find meaning from life's experiences, especially when confronting life's challenges, may be a mechanism underlying resilience. Having purpose in life may motivate reframing stressful situations to deal with them more productively, thereby facilitating recovery from stress and trauma. In turn, enhanced ability to recover from negative events may allow a person to achieve or maintain a feeling of greater purpose in life over time. In a large sample of adults (aged 36-84 years from the MIDUS study (Midlife in the U.S., http://www.midus.wisc.edu/, we tested whether purpose in life was associated with better emotional recovery following exposure to negative picture stimuli indexed by the magnitude of the eyeblink startle reflex (EBR, a measure sensitive to emotional state. We differentiated between initial emotional reactivity (during stimulus presentation and emotional recovery (occurring after stimulus offset. Greater purpose in life, assessed over two years prior, predicted better recovery from negative stimuli indexed by a smaller eyeblink after negative pictures offset, even after controlling for initial reactivity to the stimuli during the picture presentation, gender, age, trait affect, and other well-being dimensions. These data suggest a proximal mechanism by which purpose in life may afford protection from negative events and confer resilience is through enhanced automatic emotion regulation after negative emotional provocation.

  18. Fragile X mice develop sensory hyperreactivity to auditory stimuli.

    Science.gov (United States)

    Chen, L; Toth, M

    2001-01-01

    Fragile X syndrome is the most prevalent cause of mental retardation. It is usually caused by the transcriptional inactivation of the FMR-1 gene. Although the cognitive defect is the most recognized symptom of fragile X syndrome, patients also show behavioral problems such as hyperarousal, hyperactivity, autism, aggression, anxiety and increased sensitivity to sensory stimuli. Here we investigated whether fragile X mice (fmr-1 gene knockout mice) exhibit abnormal sensitivity to sensory stimuli. First, hyperreactivity of fragile X mice to auditory stimulus was indicated in the prepulse inhibition paradigm. A moderately intense prepulse tone, that suppresses startle response to a strong auditory stimulus, elicited a significantly stronger effect in fragile X than in control mice. Second, sensory hyperreactivity of fragile X mice was demonstrated by a high seizure susceptibility to auditory stimulation. Selective induction of c-Fos, an early-immediate gene product, indicated that seizures involve auditory brainstem and thalamic nuclei. Audiogenic seizures were not due to a general increase in brain excitability because three different chemical convulsants (kainic acid, bicuculline and pentylenetetrazole) elicited similar effects in fragile X and wild-type mice. These data are consistent with the increased responsiveness of fragile X patients to auditory stimuli. The auditory hypersensitivity suggests an abnormal processing in the auditory system of fragile X mice, which could provide a useful model to study the molecular and cellular changes underlying fragile X syndrome.

  19. Extended cortical activations during evaluating successive pain stimuli

    Science.gov (United States)

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

    2012-01-01

    Comparing pain is done in daily life and involves short-term memorizing and attention focusing. This event-related functional magnetic resonance imaging study investigated the short-term brain activations associated with the comparison of pain stimuli using a delayed discrimination paradigm. Fourteen healthy young volunteers compared two successive pain stimuli administered at a 10 s interval to the same location at the nasal mucosa. Fourteen age- and sex-matched subjects received similar pain stimuli without performing the comparison task. With the comparison task, the activations associated with the second pain stimulus were significantly greater than with the first stimulus in the anterior insular cortex and the primary somatosensory area. This was observed on the background of a generally increased stimulus-associated brain activation in the presence of the comparison task that included regions of the pain matrix (insular cortex, primary and secondary somatosensory area, midcingulate cortex, supplemental motor area) and regions associated with attention, decision making, working memory and body recognition (frontal and temporal gyri, inferior parietal lobule, precuneus, lingual cortices). This data provides a cerebral correlate for the role of pain as a biological alerting system that gains the subject's attention and then dominates most other perceptions and activities involving pain-specific and non-pain-specific brain regions. PMID:21768205

  20. 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

  1. Haemodynamic brain response to visual sexual stimuli is different between homosexual and heterosexual men.

    Science.gov (United States)

    Hu, S-H; Wang, Q-D; Xu, Y; Liao, Z-L; Xu, L-J; Liao, Z-L; Xu, X-J; Wei, E-Q; Yan, L-Q; Hu, J-B; Wei, N; Zhou, W-H; Huang, M-L; Zhang, M-M

    2011-01-01

    The underlying neurobiological factors involved in sexual orientation are largely unknown. This study investigated whether neural circuits or different cognitive processes accounted for differences in brain activation in 14 heterosexual and 14 homosexual males. Brain scans were undertaken in each subject using functional magnetic resonance imaging while they viewed different sexual stimuli, i.e. heterosexual couple stimuli (HCS), gay couple stimuli (GCS), lesbian couple stimuli (LCS) and neutral stimuli (NS). Ratings of sexual attractiveness of the stimuli were assessed. Subjective sexual arousal was induced by HCS and GCS in heterosexual and homosexual men, respectively. Sexual disgust was induced by GCS and LCS in heterosexual and homosexual men, respectively. Compared with viewing NS, viewing sexual stimuli induced significantly different brain activations, most of which had the characteristics of cognitive processes. These observations suggest that different cognitive patterns may be the major cause of different subjective responses to sexual stimuli between heterosexual and homosexual men.

  2. 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)

  3. Impaired attentional disengagement from stimuli matching the contents of working memory in social anxiety

    National Research Council Canada - National Science Library

    Moriya, Jun; Sugiura, Yoshinori

    2012-01-01

    Although many cognitive models in anxiety propose that an impaired top-down control enhances the processing of task-irrelevant stimuli, few studies have paid attention to task-irrelevant stimuli under...

  4. Impaired Attentional Disengagement from Stimuli Matching the Contents of Working Memory in Social Anxiety: e47221

    National Research Council Canada - National Science Library

    Jun Moriya; Yoshinori Sugiura

    2012-01-01

      Although many cognitive models in anxiety propose that an impaired top-down control enhances the processing of task-irrelevant stimuli, few studies have paid attention to task-irrelevant stimuli...

  5. Amygdala neural activity reflects spatial attention towards stimuli promising reward or threatening punishment.

    Science.gov (United States)

    Peck, Christopher J; Salzman, C Daniel

    2014-10-30

    Humans and other animals routinely identify and attend to sensory stimuli so as to rapidly acquire rewards or avoid aversive experiences. Emotional arousal, a process mediated by the amygdala, can enhance attention to stimuli in a non-spatial manner. However, amygdala neural activity was recently shown to encode spatial information about reward-predictive stimuli, and to correlate with spatial attention allocation. If representing the motivational significance of sensory stimuli within a spatial framework reflects a general principle of amygdala function, then spatially selective neural responses should also be elicited by sensory stimuli threatening aversive events. Recordings from amygdala neurons were therefore obtained while monkeys directed spatial attention towards stimuli promising reward or threatening punishment. Neural responses encoded spatial information similarly for stimuli associated with both valences of reinforcement, and responses reflected spatial attention allocation. The amygdala therefore may act to enhance spatial attention to sensory stimuli associated with rewarding or aversive experiences.

  6. 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 < 0.05) than those evoked to traditional click and tone burst stimuli. Systematic statistically significant (p < 0.05) wave V latency differences existed between the air- and bone-conducted 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.

  7. Measuring 'expected satiety' in a range of common foods using a method of constant stimuli.

    Science.gov (United States)

    Brunstrom, Jeffrey M; Shakeshaft, Nicholas G; Scott-Samuel, Nicholas E

    2008-11-01

    Humans have expectations about the satiety that is likely to develop after consuming particular foods. These expectations are potentially important, because they may influence decisions about meal size. Despite this, very little is known about the basis on which satiety expectations are formulated. This work introduces a methodology (based on a method of constant stimuli) that quantifies differences in expectations across foods. In Experiment 1 (N=52) and Experiment 2 (N=76) we compared expectations across 4 and 18 common foods, respectively. We discovered that a considerable mismatch occurs between satiety expectations and the energy content of foods (e.g., 200 kcal of pasta and 894 kcal of cashew nuts are expected to deliver equal satiety). This difference may reflect physical or macronutrient characteristics of these foods--energy-dense and high-fat foods have significantly lower 'ratios of expected satiety.' We also found a highly significant relationship between food familiarity and expected satiety (r=0.86, p<0.001), suggesting that expected-satiety judgements are learned. Across experiments, we were able to confirm both the reliability and robustness of our empirical approach. Future use of this methodology is discussed, both in relation to our understanding of portion-size decisions and its application more generally.

  8. 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

  9. PENILAIAN PEDOFILIA MENGGUNAKAN RESPON HEMODINAMIK OTAK TERHADAP STIMULI SEKSUAL

    Directory of Open Access Journals (Sweden)

    Kuhelan Mahendran

    2015-09-01

    Full Text Available ABSTRAK Menilai secara akurat orientasi seksual seseorang sangat penting dalam melakukan penanganan terhadap pelaku kekerasan seksual pada anak. Phallometry adalah metode standar untuk mengidentifikasi orientasi seksual; tetapi, metode ini telah banyak dikritik oleh karena bersifat intrusif dan reliabilitasnya terbatas. Tujuan:Untuk mengevaluasi apakah pola respon spasial terhadap stimuli seksual yang ditandai oleh adanya perubahan blood oxygen level-dependent signal (BOLDmemfasilitasi proses identifikasi pedofilia. Desain:Selama dilakukan pemeriksaan magnetic resonance imaging fungsional (fMRI, ditampilkan gambar anak-anak dan dewasa tanpa busana dengan jenis kelamin sama atau berbeda terhadap sampel penelitian (kelompok pedofil dan kontrol. Kami mengkalkulasi perbedaan BOLDterhadap stimuli sexual anak-anak dan dewasa pada setiap sampel. Hasil foto dengan kontras kemudian dimasukkan sesuai dengan kelompoknya untuk dianalisis perbedaan pemetaan otak antara kelompok pedofil dan kontrol. Kami mengkalkulasi nilai ekspresi yang sesuai dengan hasil kelompok bagi setiap sampel. Nilai ekspresi tersebut dibedakan menjadi 2 algoritma klasifikasi: analisis Fisher linear discriminant dan analisis -nearest neighbor. Prosedur klasifikasi tersebut telah divalidasi silang menggunakan metode leave-one-out. Lokasi:Bagian Kedokteran Seksual, Fakultas Kedokteran Universitas Christian Albrechts di Kiel, Jerman. Sampel:Kami merekrut 24 sampel dengan pedofil yang memiliki ketertarikan seksual terhadap anak perempuan (n=11 atau laki-laki (n=13 pre pubertas dan 32 kontrol laki-laki sehat yang memiliki ketertarikan seksual terhadap wanita (n=18 atau pria (n=14 dewasa. Pengukuran luaran utama:Angka sensitivitasdan spesifisitas dari kedua algoritme klasifikasi. Hasil:Akurasi klasifikasi tertinggi dicapai dengan analisis diskriminan linear Fisher, yang menunjukkan akurasi rata-rata 95% (100% spesifisitas, 88% sensitivitas. Simpulan:Pola respon otak fungsional terhadap

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

    Science.gov (United States)

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

    2014-06-01

    People with Rett syndrome (RTT) have severe communicative difficulties. They have as well an immature brainstem that implies dysfunction of the autonomic nervous system. Music plays an important role in their life, is often used as a motivating tool in a variety of situations and activities, and caregivers are often clear about people with RTTs favourites. The aim of this study was to investigate physiological and emotional responses related to six different musical stimuli in people with RTT. The study included 29 participants with RTT who were referred to the Swedish Rett Center for medical brainstem assessment during the period 2006-2007. 11 children with a typical developmental pattern were used as comparison. A repeated measures design was used, and physiological data were collected from a neurophysiological brainstem assessment. The continuous dependent variables measured were Cardiac Vagal Tone (CVT), Cardiac Sensitivity to Baroreflex (CSB), Mean Arterial Blood Pressure (MAP) and the Coefficient of Variation of Mean Arterial Blood Pressure (MAP-CV). These parameters were used to categorise brainstem responses as parasympathetic (calming) response, sympathetic (activating) response, arousal (alerting) response and unclear response. The results showed that all participants responded to the musical stimuli, but not always in the expected way. It was noticeable that both people with and without RTT responded with an arousal to all musical stimuli to begin with. Even though the initial expressions sometimes changed after some time due to poor control functions of their brainstem, the present results are consistent with the possibility that the RTT participants' normal responses to music are intact. These findings may explain why music is so important for individuals with RTT throughout life. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Modulating the processing of emotional stimuli by cognitive demand.

    Science.gov (United States)

    Kellermann, Tanja S; Sternkopf, Melanie A; Schneider, Frank; Habel, Ute; Turetsky, Bruce I; Zilles, Karl; Eickhoff, Simon B

    2012-03-01

    Emotional processing is influenced by cognitive processes and vice versa, indicating a profound interaction of these domains. The investigation of the neural mechanisms underlying this interaction is not only highly relevant for understanding the organization of human brain function. Rather, it may also help in understanding dysregulated emotions in affective disorders and in elucidating the neurobiology of cognitive behavioural therapy (e.g. in borderline personality disorder), which aims at modulating dysfunctional emotion processes by cognitive techniques, such as restructuring. In the majority of earlier studies investigating the interaction of emotions and cognition, the main focus has been on the investigation of the effects of emotional stimuli or, more general, emotional processing, e.g. instituted by emotional material that needed to be processed, on cognitive performance and neural activation patterns. Here we pursued the opposite approach and investigated the modulation of implicit processing of emotional stimuli by cognitive demands using an event-related functional magnetic resonance imaging--study on a motor short-term memory paradigm with emotional interferences. Subjects were visually presented a finger-sequence consisting either of four (easy condition) or six (difficult condition) items, which they had to memorize. After a short pause positive, negative or neutral International affective picture system pictures or a green dot (as control condition) were presented. Subjects were instructed to reproduce the memorized sequence manually as soon as the picture disappeared. Analysis showed that with increasing cognitive demand (long relative to short sequences), neural responses to emotional pictures were significantly reduced in amygdala and orbitofrontal cortex. In contrast, the more difficult task evoked stronger activation in a widespread frontoparietal network. As stimuli were task-relevant go-cues and hence had to be processed perceptually, we

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

    Science.gov (United States)

    Rømer Thomsen, Kristine; Lou, Hans C; Joensson, Morten; Hyam, Jonathan A; Holland, Peter; Parsons, Christine E; Young, Katherine S; Møller, Arne; Stein, Alan; Green, Alex L; Kringelbach, Morten L; Aziz, Tipu Z

    2011-04-11

    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 ACC.

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

    Directory of Open Access Journals (Sweden)

    Kristine Rømer Thomsen

    2011-04-01

    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

  14. Napping promotes inter-session habituation to emotional stimuli.

    Science.gov (United States)

    Pace-Schott, Edward F; Shepherd, Elizabeth; Spencer, Rebecca M C; Marcello, Matthew; Tucker, Matthew; Propper, Ruth E; Stickgold, Robert

    2011-01-01

    The effects of a daytime nap on inter-session habituation to aversive visual stimuli were investigated. Healthy young adult volunteers viewed repeated presentations of highly negative and emotionally neutral (but equally arousing) International Affective Picture System (IAPS) photographs during two afternoon sessions separated by 2.5h. Half of the photographs were shown at both sessions (Repeated Sets) and half differed between sessions (Novel Sets). For each stimulus presentation, evoked skin conductance response (SCR), heart-rate deceleration (HRD) and corrugator supercilii EMG response (EMG), were computed and range corrected using respective maximum session-1 responses. Following each presentation, subjects rated each photograph on dimensions of pleasantness and arousability. During the inter-session interval, Nap subjects had a 120-min polysomnographically monitored sleep opportunity, whereas Wake subjects watched a non-stimulating video. Nap and Wake subjects did not differ in their subjective ratings of photographs. However, for Repeated-Set photographs, Nap subjects demonstrated greater inter-session habituation in SCR and EMG but a trend toward lesser inter-session habituation in HRD. These group differences were absent for Novel-Set photographs. Group differences across all measures were greater for negative stimuli. Occurrence of SWS during the nap was associated with greater inter-session habituation of EMG whereas occurrence of REM was associated with lesser inter-session habituation of SCR to negative stimuli. Sleep may therefore promote emotional adjustment at the level of somatic responses. Physiological but not subjective inter-session habituation to aversive images was enhanced by a daytime nap. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. 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

  16. Adhesion Characteristics and Swelling Response of Stimuli-Responsive Hydrogels

    Science.gov (United States)

    Benjamin, Chandler

    Stimuli-responsive hydrogels are a class of shape memory materials that have been successfully used in microfluidic and biomedical devices and additionally as biomaterials. These materials operate in a hydrated environment and respond with a significant volumetric reversible transformation through absorption or release of water within the polymeric network. The pH sensitive 2-hydroxyethyl methacrylate (2-dimethylamino) ethyl methacrylate, (HEMA-DMAEMA) stimuli-responsive hydrogel is used in microfluidic devices as sensors and actuators. This hydrogel responds to an acidic aqueous environment with a subsequent volume change. This actuation requires the hydrogel to be in an acidic environment to remain in its swollen state. In chapter 2 I initially characterize this hydrogel in terms of engineering properties such as the storage modulus G', the loss modulus G'' and loss tangent tan(delta). The storage modulus is analogous to the shear modulus from elasticity theory. The loss modulus is a representation of energy dissipation from applied loading. The loss tangent tan(delta) is a measure of damping in a material. In chapter 3 I develop a method of measuring the Fung parameter beta° for stimuli-responsive hydrogels using a simple tensile test. HEMA-DMAEMA stimuli-responsive hydrogels are examined using this method. The HEMA-DMAEMA is pre-conditioned in 3.0 (acidic) pH and 11.0 (basic) pH buffer solutions prior to testing to compare the theoretical results to experiment in both the swollen and unswollen states. The measured Fung parameter beta° is 0.870 +/- 0.018. In chapter 4 I examine the interfacial adhesion of HEMA-DMAEMA. Experimental observations have given indications that the adhesion of the (HEMA-DMAEMA) is effected by substrate modifications. Using a unique experimental technique coupled with concepts from fracture mechanics I measure differences in the adhesive strength of HEMA-DMAEMA on borosilicate glass substrates, both unmodified and with different

  17. Facilitated processing of visual stimuli associated with the body

    DEFF Research Database (Denmark)

    Whiteley, Louise Emma; Kennett, Steffan; Taylor-Clarke, Marisa

    2004-01-01

    Recent work on tactile perception has revealed enhanced tactile acuity and speeded spatial-choice reaction times (RTs) when viewing the stimulated body site as opposed to viewing a neutral object. Here we examine whether this body-view enhancement effect extends to visual targets. Participants...... was projected onto a screen in front of the participants. Thus, participants responded to identical visual targets varying only in their context: on the body or not. Results revealed a large performance advantage for the finger-mounted stimuli: reaction times were substantially reduced, while discrimination...

  18. 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

  19. Stimuli-responsive Hydrogels for Textile Functionalisation: A Review

    Directory of Open Access Journals (Sweden)

    Štular Danaja

    2017-06-01

    Full Text Available This article reviews hydrogels used for the functionalisation of textile materials. Hydrogels are reviewed according to their reason for incorporation, aspects of crosslinking, stimuli-responsive characteristics and particle size. A more in-depth focus on the effect of hydrogel particle size is provided, where macrogels, microgels and nanogels for textile functionalisation are considered. The advantages and disadvantages of each size group are presented. Furthermore, the correlation between synthesis conditions and the sizes of hydrogel particles is discussed, in addition to the applications of macro-, micro- and nanogels to textile materials and their intended uses.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    People with Rett syndrome (RTT) have severe communicative difficulties. They have as well an immature brainstem that implies dysfunction of the autonomic nervous system. Music plays an important role in their life, is often used as a motivating tool in a variety of situations and activities......, and caregivers are often clear about people with RTTs favourites. The aim of this study was to investigate physiological and emotional responses related to six different musical stimuli in people with RTT. The study included 29 participants with RTT who were referred to the Swedish Rett Center for medical...

  1. Assessment of the Relatedness of Equivalent Stimuli through a Semantic Differential

    Science.gov (United States)

    Bortoloti, Renato; de Rose, Julio C.

    2009-01-01

    If stimulus equivalence is a model of meaning, abstract stimuli should acquire the meaning of meaningful stimuli equivalent to them. In Experiment 1, college students matched faces expressing emotions to arbitrary pictures, forming three classes of equivalent stimuli, each comprising an emotional expression and three arbitrary pictures. Semantic…

  2. Components of the event-related potential following degraded and undegraded visual stimuli.

    NARCIS (Netherlands)

    Kok, A.; de Looren de Jong, H.

    1980-01-01

    Event-related potentials were recorded in response to visual stimuli in 2 reaction tasks in which 12 right-handed male undergraduates were instructed to react immediately to the stimuli, or to delay their response for 2 sec. There were 4 types of stimuli: frequent-degraded, frequent-undegraded,

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

    Science.gov (United States)

    Kim, Young-Suk Grace

    2016-01-01

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

  4. 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

  5. Effects of boar stimuli on the follicular phase and on oestrous behaviour in sows

    NARCIS (Netherlands)

    Langendijk, P.; Soede, N.M.; Kemp, B.

    2006-01-01

    This review describes the role of boar stimuli in receptive behaviour, and the influence of boar stimuli during the follicular phase. Receptive behaviour (standing response) in an oestrous sow is elicited by boar stimuli, which can be olfactory, auditory, tactile, or visual. The relative importance

  6. 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

  7. 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.

  8. 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.

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

    Science.gov (United States)

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

    2005-04-01

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

  10. Emotional stimuli exert parallel effects on attention and memory.

    Science.gov (United States)

    Talmi, Deborah; Ziegler, Marilyne; Hawksworth, Jade; Lalani, Safina; Herman, C Peter; Moscovitch, Morris

    2013-01-01

    Because emotional and neutral stimuli typically differ on non-emotional dimensions, it has been difficult to determine conclusively which factors underlie the ability of emotional stimuli to enhance immediate long-term memory. Here we induced arousal by varying participants' goals, a method that removes many potential confounds between emotional and non-emotional items. Hungry and sated participants encoded food and clothing images under divided attention conditions. Sated participants attended to and recalled food and clothing images equivalently. Hungry participants performed worse on the concurrent tone-discrimination task when they viewed food relative to clothing images, suggesting enhanced attention to food images, and they recalled more food than clothing images. A follow-up regression analysis of the factors predicting memory for individual pictures revealed that food images had parallel effects on attention and memory in hungry participants, so that enhanced attention to food images did not predict their enhanced memory. We suggest that immediate long-term memory for food is enhanced in the hungry state because hunger leads to more distinctive processing of food images rendering them more accessible during retrieval.

  11. Switchable Bioelectrocatalysis Controlled by Dual Stimuli-Responsive Polymeric Interface.

    Science.gov (United States)

    Parlak, Onur; Ashaduzzaman, Md; Kollipara, Suresh B; Tiwari, Ashutosh; Turner, Anthony P F

    2015-11-04

    The engineering of bionanointerfaces using stimuli-responsive polymers offers a new dimension in the design of novel bioelectronic interfaces. The integration of electrode surfaces with stimuli-responsive molecular cues provides a direct control and ability to switch and tune physical and chemical properties of bioelectronic interfaces in various biodevices. Here, we report a dual-responsive biointerface employing a positively responding dual-switchable polymer, poly(NIPAAm-co-DEAEMA)-b-HEAAm, to control and regulate enzyme-based bioelectrocatalysis. The design interface exhibits reversible activation-deactivation of bioelectrocatalytic reactions in response to change in temperature and in pH, which allows manipulation of biomolecular interactions to produce on/off switchable conditions. Using electrochemical measurements, we demonstrate that interfacial bioelectrochemical properties can be tuned over a modest range of temperature (i.e., 20-60 °C) and pH (i.e., pH 4-8) of the medium. The resulting dual-switchable interface may have important implications not only for the design of responsive biocatalysis and on-demand operation of biosensors, but also as an aid to elucidating electron-transport pathways and mechanisms in living organisms by mimicking the dynamic properties of complex biological environments and processes.

  12. Modeling drug release through stimuli responsive polymer hydrogels.

    Science.gov (United States)

    Pareek, Aditya; Maheshwari, Shantanu; Cherlo, Sivakumar; Thavva, Rama Subba Reddy; Runkana, Venkataramana

    2017-10-30

    There is a rising interest in stimuli-responsive hydrogels to achieve controlled and self-regulated drug delivery. Stimuli responsive polymer hydrogels with their ability to swell/de-swell under varying pH conditions present themselves as a potential candidate for controlled drug delivery. It is important to develop a mechanistic understanding of the underlying phenomena that will help suggest ways to control the drug release from a polymer hydrogel. We present a mathematical model that couples Nernst-Planck, Poisson and force balance equations to incorporate diffusion of ionic species and drug along with deformation of hydrogel under osmotic pressure. The model can be used to simulate swelling behaviour of the hydrogel along with the kinetics of drug release. It has been validated with published experimental data for swelling of polyhydroxyl methacrylate-co-methacrylic acid (pHEMA-co-MA) gels and release kinetics of Phenylpropanolamine from these gels. Effect of formulation parameters such as polymer concentration and cross-linker concentration has also been evaluated. The model can be used to reduce the number of exploratory experiments required during design of a drug delivery system. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Moving Stimuli Facilitate Synchronization But Not Temporal Perception.

    Science.gov (United States)

    Silva, Susana; Castro, São Luís

    2016-01-01

    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.

  14. P3a from visual stimuli: typicality, task, and topography.

    Science.gov (United States)

    Polich, John; Comerchero, Marco D

    2003-01-01

    A visual three-stimulus (target, nontarget, standard) paradigm was employed in which subjects responded only to the target. Nontarget stimulus properties were varied systematically to evaluate how stimulus typicality (non-novel vs. novel) across task discrimination (easy vs. difficult) conditions affects P3a scalp topography. Nontarget stimuli consisted of letters, small squares, large squares, and novel patterns; discrimination difficulty between the target and standard was varied across conditions. When the discrimination was easy, P300 amplitude was larger for the target than the nontarget with parietal maximums for both. In contrast, when the discrimination was difficult, nontarget amplitude (P3a) was larger and earlier than the target P300 over the frontal/central electrode sites, whereas target amplitude (P3b) was larger parietally and occurred later. P3a was largest when elicited by either the large square or novel pattern stimuli. The findings suggest that stimulus context as defined by the target/standard discrimination difficulty rather than stimulus novelty determines P3a generation.

  15. 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.

  16. Coding of stimuli by ampullary afferents in Gnathonemus petersii.

    Science.gov (United States)

    Engelmann, J; Gertz, S; Goulet, J; Schuh, A; von der Emde, G

    2010-10-01

    Weakly electric fish use electroreception for both active and passive electrolocation and for electrocommunication. While both active and passive electrolocation systems are prominent in weakly electric Mormyriform fishes, knowledge of their passive electrolocation ability is still scarce. To better estimate the contribution of passive electric sensing to the orientation toward electric stimuli in weakly electric fishes, we investigated frequency tuning applying classical input-output characterization and stimulus reconstruction methods to reveal the encoding capabilities of ampullary receptor afferents. Ampullary receptor afferents were most sensitive (threshold: 40 μV/cm) at low frequencies (thresholds were one order of magnitude higher. The integration of simultaneously recorded afferents of similar frequency-tuning resulted in strongly enhanced signal-to-noise ratios and increased mutual information rates but did not increase the range of frequencies detectable by the system. Theoretically the neuronal integration of input from receptors experiencing opposite polarities of a stimulus (left and right side of the fish) was shown to enhance encoding of such stimuli, including an increase of bandwidth. Covariance and coherence analysis showed that spiking of ampullary afferents is sufficiently explained by the spike-triggered average, i.e., receptors respond to a single linear feature of the stimulus. Our data support the notion of a division of labor of the active and passive electrosensory systems in weakly electric fishes based on frequency tuning. Future experiments will address the role of central convergence of ampullary input that we expect to lead to higher sensitivity and encoding power of the system.

  17. 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.

  18. Functional neurological symptoms modulate processing of emotionally salient stimuli.

    Science.gov (United States)

    Fiess, Johanna; Rockstroh, Brigitte; Schmidt, Roger; Wienbruch, Christian; Steffen, Astrid

    2016-12-01

    Dysfunctional emotion processing has been discussed as a contributing factor to functional neurological symptoms (FNS) in the context of conversion disorder, and refers to blunted recognition and the expression of one's own feelings. However, the emotion processing components characteristic for FNS and/or relevant for conversion remain to be specified. With this goal, the present study targeted the initial, automatic discrimination of emotionally salient stimuli. The magnetoencephalogram (MEG) was monitored in 21 patients with functional weakness and/or sensory disturbance subtypes of FNS and 21 healthy comparison participants (HC) while they passively watched 600 emotionally arousing, pleasant, unpleasant or neutral stimuli in a rapid serial visual presentation (RSVP) design. Neuromagnetic activity was analyzed 110-330ms following picture onset in source space for prior defined posterior and central regions of interest. As early as 110ms and across presentation interval, posterior neural activity modulation by picture category was similar in both groups, despite smaller initial (110-150ms) overall and posterior power in patients with FNS. The initial activity modulation by picture category was also evident in the left sensorimotor area in patients with FNS, but not significant in HC. Similar activity modulation by emotional picture category in patients with FNS and HC suggests that the fast, automatic detection of emotional salience is unchanged in patients with FNS, but involves an emotion-processing network spanning posterior and sensorimotor areas. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

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

    Science.gov (United States)

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

    1999-01-01

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

  5. 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.

  6. Developing realistic stimuli for assessing observers' perceptions of male and female body types.

    Science.gov (United States)

    Salusso-Deonier, C J; Markee, N L; Pedersen, E L

    1991-04-01

    The goal of this research was to create more realistic stimuli for research in assessing observers' perceptions of male and female body types. Stimuli were developed by classifying large samples of photographs and using representative photographs to illustrate body types. Resultant stimuli go beyond current stereotypic stimuli to provide realistic representations of commonly occurring body types among men and women ages 18 ro 40 years. Realistic stimuli can be used in a wide range of research both to understand observer perceptions and to teach the reality of human variation.

  7. Oral microflora in infants delivered vaginally and by caesarean section

    DEFF Research Database (Denmark)

    Nelun Barfod, Mette; Magnusson, Kerstin; Lexner, Michala Oron

    2011-01-01

    International Journal of Paediatric Dentistry 2011 Background. Early in life, vaginally delivered infants exhibit a different composition of the gut flora compared with infants delivered by caesarean section (C-section); however, it is unclear whether this also applies to the oral cavity. Aim...

  8. The Use of Freshmen Seminar Programs to Deliver Personalized Feedback

    Science.gov (United States)

    Henslee, Amber M.; Correia, Christopher J.

    2009-01-01

    The current study tested the effectiveness of delivering personalized feedback to first-semester college freshmen in a group lecture format. Participants enrolled in semester-long courses were randomly assigned to receive either personalized feedback or general information about alcohol. Both lecture conditions were delivered during a standard…

  9. A Randomized Trial of Contingency Management Delivered by Community Therapists

    Science.gov (United States)

    Petry, Nancy M.; Alessi, Sheila M.; Ledgerwood, David M.

    2012-01-01

    Objective: Contingency management (CM) is an evidence-based treatment, but few clinicians deliver this intervention in community-based settings. Method: Twenty-three clinicians from 3 methadone maintenance clinics received training in CM. Following a didactics seminar and a training and supervision period in which clinicians delivered CM to pilot…

  10. [The P300-based brain-computer interface: presentation of the complex "flash + movement" stimuli].

    Science.gov (United States)

    Ganin, I P; Kaplan, A Ia

    2014-01-01

    The P300 based brain-computer interface requires the detection of P300 wave of brain event-related potentials. Most of its users learn the BCI control in several minutes and after the short classifier training they can type a text on the computer screen or assemble an image of separate fragments in simple BCI-based video games. Nevertheless, insufficient attractiveness for users and conservative stimuli organization in this BCI may restrict its integration into real information processes control. At the same time initial movement of object (motion-onset stimuli) may be an independent factor that induces P300 wave. In current work we checked the hypothesis that complex "flash + movement" stimuli together with drastic and compact stimuli organization on the computer screen may be much more attractive for user while operating in P300 BCI. In 20 subjects research we showed the effectiveness of our interface. Both accuracy and P300 amplitude were higher for flashing stimuli and complex "flash + movement" stimuli compared to motion-onset stimuli. N200 amplitude was maximal for flashing stimuli, while for "flash + movement" stimuli and motion-onset stimuli it was only a half of it. Similar BCI with complex stimuli may be embedded into compact control systems requiring high level of user attention under impact of negative external effects obstructing the BCI control.

  11. The value of social attributes of stimuli for promoting engagement in persons with dementia.

    Science.gov (United States)

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

    2010-08-01

    The present study examined the impact of different attributes of social stimuli using the stimulus attributes aspect of the Comprehensive Process Model of Engagement ( Am J Geriatr Psychiatry. 17:299-307). Participants were 193 residents of 7 Maryland nursing homes with a diagnosis of dementia. Stimuli were chosen to represent different levels of the following social attributes: social versus not social, realistic versus not realistic, animated versus nonanimated, human versus nonhuman, and alive versus not alive. Participants had significantly longer engagement, were significantly more attentive, and displayed a significantly more positive attitude with social stimuli than with nonsocial stimuli. Longer durations and higher ratings of attention and attitude were seen with realistic and animated stimuli as compared to their counterparts. Human and live stimuli resulted in significantly more engagement than their counterparts. Giving any social stimulus to the residents is preferable to providing none, and the social attributes of stimuli should be maximized.

  12. 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…

  13. Increased visual task difficulty enhances attentional capture by both visual and auditory distractor stimuli.

    Science.gov (United States)

    Sugimoto, Fumie; Katayama, Jun'ichi

    2017-06-01

    Previous studies using a three-stimulus oddball task have shown the amplitude of P3a elicited by distractor stimuli increases when perceptual discrimination between standard and target stimuli becomes difficult. This means that the attentional capture by the distractor stimuli is enhanced along with an increase in task difficulty. So far, the increase of P3a has been reported when standard, target, and distractor stimuli were presented within one sensory modality (i.e., visual or auditory). In the present study, we further investigated whether or not the increase of P3a can also be observed when the distractor stimuli are presented in a different modality from the standard and target stimuli. Twelve participants performed a three-stimulus oddball task in which they were required to discriminate between visual standard and target stimuli. As the distractor stimuli, either another visual stimulus or an auditory stimulus was presented in separate blocks. Visual distractor stimuli elicited P3a, and its amplitude increased when visual standard/target discrimination was difficult, replicating previous findings. Auditory distractor stimuli elicited P3a, and importantly, its amplitude also increased when visual standard/target discrimination was difficult. This result means that attentional capture by distractor stimuli can be enhanced even when the distractor stimuli are presented in a different modality from the standard and target stimuli. Possible mechanisms and implications are discussed in terms of the relative saliency of distractor stimuli, influences of temporal/spatial attention, and the load involved in a task. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. 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

  15. Cortical responses to salient nociceptive and not nociceptive stimuli in vegetative and minimal conscious state

    Science.gov (United States)

    de Tommaso, Marina; Navarro, Jorge; Lanzillotti, Crocifissa; Ricci, Katia; Buonocunto, Francesca; Livrea, Paolo; Lancioni, Giulio E.

    2015-01-01

    Aims: Questions regarding perception of pain in non-communicating patients and the management of pain continue to raise controversy both at a clinical and ethical level. The aim of this study was to examine the cortical response to salient visual, acoustic, somatosensory electric non-nociceptive and nociceptive laser stimuli and their correlation with the clinical evaluation. Methods: Five Vegetative State (VS), 4 Minimally Conscious State (MCS) patients and 11 age- and sex-matched controls were examined. Evoked responses were obtained by 64 scalp electrodes, while delivering auditory, visual, non-noxious electrical and noxious laser stimulation, which were randomly presented every 10 s. Laser, somatosensory, auditory and visual evoked responses were identified as a negative-positive (N2-P2) vertex complex in the 500 ms post-stimulus time. We used Nociception Coma Scale-Revised (NCS-R) and Coma Recovery Scale (CRS-R) for clinical evaluation of pain perception and consciousness impairment. Results: The laser evoked potentials (LEPs) were recognizable in all cases. Only one MCS patient showed a reliable cortical response to all the employed stimulus modalities. One VS patient did not present cortical responses to any other stimulus modality. In the remaining participants, auditory, visual and electrical related potentials were inconstantly present. Significant N2 and P2 latency prolongation occurred in both VS and MCS patients. The presence of a reliable cortical response to auditory, visual and electric stimuli was able to correctly classify VS and MCS patients with 90% accuracy. Laser P2 and N2 amplitudes were not correlated with the CRS-R and NCS-R scores, while auditory and electric related potentials amplitude were associated with the motor response to pain and consciousness recovery. Discussion: pain arousal may be a primary function also in vegetative state patients while the relevance of other stimulus modalities may indicate the degree of cognitive and motor

  16. Response of juvenile scalloped hammerhead sharks to electric stimuli.

    Science.gov (United States)

    Kajiura, Stephen M; Fitzgerald, Timothy P

    2009-01-01

    Sharks can use their electrosensory system to detect electric fields in their environment. Measurements of their electrosensitivity are often derived by calculating the voltage gradient from a model of the charge distribution for an ideal dipole. This study measures the charge distribution around a dipole in seawater and confirms the close correspondence with the model. From this, it is possible to predict how the sharks will respond to dipolar electric fields comprised of differing parameters. We tested these predictions by exposing sharks to different sized dipoles and levels of applied current that simulated the bioelectric fields of their natural prey items. The sharks initiated responses from a significantly greater distance with larger dipole sizes and also from a significantly greater distance with increasing levels of electric current. This study is the first to provide empirical evidence supporting a popular theoretical model and test predictions about how sharks will respond to a variety of different electric stimuli.

  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. Brainstem electrical responses from selected tone pip stimuli.

    Science.gov (United States)

    Wood, M H; Seitz, M R; Jacobson, J T

    1979-01-01

    Brainstem-electrical responses were obtained from 10 normal hearing adult subjects using frequency specific tone pips as stimuli. The four frequency specific tone pips (500, 1000, 2000, and 4000 Hz) were diamond shaped with a 2.5-msec rise/fall time. Each tone pip was presented at four intensity levels (70, 50, 30, and 10 dB hearing threshold level), and graphic recordings were made for each frequency at the specific intensity levels. Frequency specific Wave V intensity-latency functions were plotted, and these results were compared to tone pip data obtained in previous studies. In addition, suggested test procedures for obtaining tone pip brainstem-evoked responses under diagnostic conditions are discussed.

  19. Hsp27 protects mitochondria of thermotolerant cells against apoptotic stimuli

    Science.gov (United States)

    Samali, Afshin; Robertson, John D.; Peterson, Elisabeth; Manero, Florence; van Zeijl, Leone; Paul, Catherine; Cotgreave, Ian A.; Arrigo, André-Patrick; Orrenius, Sten

    2001-01-01

    Enhanced cell survival and resistance to apoptosis during thermotolerance correlates with an increased expression of heat shock proteins (Hsps). Here we present additional evidence in support of the hypothesis that the induction of Hsp27 and Hsp72 during acquired thermotolerance in Jurkat T-lymphocytes prevents apoptosis. In thermotolerant cells, Hsp27 was shown to associate with the mitochondrial fraction, and inhibition of Hsp27 induction during thermotolerance in cells transfected with hsp27 antisense potentiated mitochondrial cytochrome c release after exposure to various apoptotic stimuli, despite the presence of elevated levels of Hsp72. Caspase activation and apoptosis were inhibited under these conditions. In vitro studies revealed that recombinant Hsp72 more efficiently blocked cytochrome c–mediated caspase activation than did recombinant Hsp27. A model is presented for the inhibition of apoptosis during thermotolerance in which Hsp27 preferentially blocks mitochondrial cytochrome c release, whereas Hsp72 interferes with apoptosomal caspase activation. PMID:11525243

  20. 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.

  1. P3a from visual stimuli: task difficulty effects.

    Science.gov (United States)

    Hagen, Galen F; Gatherwright, James R; Lopez, Brian A; Polich, John

    2006-01-01

    The P3a event-related brain potential (ERP) was elicited using a visual three-stimulus oddball paradigm (target, standard, distracter) in which participants responded only to the target. Discrimination task difficulty between the target and the standard was manipulated by varying the size of the standard stimulus circle relative to a constant target stimulus circle across three conditions (easy, medium, hard). A large checkerboard pattern was employed for the distracter stimulus across all tasks. Error rate and response time increased with increases in task difficulty, so that the task difficulty manipulation was successful. Distracter P3a amplitude increased and target P3b decreased somewhat with increases in task difficulty. The findings suggest that increased perceptual discrimination difficulty between the target and standard stimuli increases P3a amplitude. Theoretical implications are discussed.

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

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2009-01-01

    Binaural pitch is a tonal sensation produced by introducing a frequency-dependent interaural phase shift in binaurally presented white noise. As no spectral cues are present in the physical stimulus, binaural pitch perception is assumed to rely on accurate temporal fine structure coding and intact...... binaural integration mechanisms. This study investigated to what extent basic auditory measures of binaural processing as well as cognitive abilities are correlated with the ability of hearing-impaired listeners to perceive binaural pitch. Subjects from three groups (1: normal-hearing; 2: cochlear...... 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...

  3. Affective response to a set of new musical stimuli.

    Science.gov (United States)

    Hill, W Trey; Palmer, Jack A

    2010-04-01

    Recently, a novel set of musical stimuli was developed in an attempt to bring more rigor to a paradigm which often falls under scientific scrutiny. Although these musical clips were validated in terms of recognition for emotion, valence, and arousal, the clips were not specifically tested for their ability to elicit certain affective responses. The present study examined self-reported "elation" among 82 participants after listening to one of two types of the musical clips; 47 listened to happy music and 35 listened to sad music. Individuals who listened to happy music reported significantly higher "elation" than individuals who listened to the sad music. These results support the idea that music can elicit certain affective state responses.

  4. 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...

  5. 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.

  6. 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.

  7. Stimuli-Responsive Peptide-based Triblock and Star Copolymers

    Science.gov (United States)

    Ray, Jacob; Naik, Sandeep; Johnson, Ashley; Ly, Jack; Savin, Daniel

    2011-03-01

    Stimuli-responsive copolymers demonstrate diverse aggregation behavior in aqueous solution. In general, the molecular architecture and the balance of hydrophilic and hydrophobic volumes influence morphology. This study involves polypeptide-based ABA linear triblock and AB2 star copolymer (which structurally resemble phospholipids) amphiphiles. Model systems for this study are poly(L-lysine)-b-poly(propylene oxide)-b-poly(L-lysine) (KPK) triblocks and poly(L-glutamate) (PE) based star copolymers. Extensive studies with KPK systems have resulted in morphological transitions by modifying pH, and we hypothesize that a change in individual chain conformation is the driving force for these transitions. Preliminary results for PE-based star copolymers with various hydrophobic moieties suggest polymersome (vesicle) formation. Light scattering (dynamic and static) and TEM were used to determine aggregate size and morphology as a function of pH; furthermore, circular dichroism (CD) spectroscopy was used to measure helix-to-coil transitions of the polypeptide blocks.

  8. Pupillary response to direct and consensual chromatic light stimuli

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...... and software. Subjects were randomized to receive light stimuli at either the right or left eye after 5 min of dark adaptation. Pupil light responses were recorded in both eyes for 10 seconds before illumination, during illumination and 50 seconds after illumination with red and blue light. Three variables...... were defined for the recorded pupil responses: the maximal constriction amplitude (CAmax ), the pupil response during illumination and postillumination pupil response (PIPR). RESULTS: No difference was found in the pupil response to blue light. With red light, the pupil response during illumination...

  9. Visual laterality in dolphins: importance of the familiarity of stimuli

    Science.gov (United States)

    2012-01-01

    Background Many studies of cerebral asymmetries in different species lead, on the one hand, to a better understanding of the functions of each cerebral hemisphere and, on the other hand, to develop an evolutionary history of hemispheric laterality. Our animal model is particularly interesting because of its original evolutionary path, i.e. return to aquatic life after a terrestrial phase. The rare reports concerning visual laterality of marine mammals investigated mainly discrimination processes. As dolphins are migrant species they are confronted to a changing environment. Being able to categorize new versus familiar objects would allow dolphins a rapid adaptation to novel environments. Visual laterality could be a prerequisite to this adaptability. To date, no study, to our knowledge, has analyzed the environmental factors that could influence their visual laterality. Results We investigated visual laterality expressed spontaneously at the water surface by a group of five common bottlenose dolphins (Tursiops truncatus) in response to various stimuli. The stimuli presented ranged from very familiar objects (known and manipulated previously) to familiar objects (known but never manipulated) to unfamiliar objects (unknown, never seen previously). At the group level, dolphins used their left eye to observe very familiar objects and their right eye to observe unfamiliar objects. However, eyes are used indifferently to observe familiar objects with intermediate valence. Conclusion Our results suggest different visual cerebral processes based either on the global shape of well-known objects or on local details of unknown objects. Moreover, the manipulation of an object appears necessary for these dolphins to construct a global representation of an object enabling its immediate categorization for subsequent use. Our experimental results pointed out some cognitive capacities of dolphins which might be crucial for their wild life given their fission-fusion social system

  10. 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.

  11. Visual laterality in dolphins: importance of the familiarity of stimuli

    Directory of Open Access Journals (Sweden)

    Blois-Heulin Catherine

    2012-01-01

    Full Text Available Abstract Background Many studies of cerebral asymmetries in different species lead, on the one hand, to a better understanding of the functions of each cerebral hemisphere and, on the other hand, to develop an evolutionary history of hemispheric laterality. Our animal model is particularly interesting because of its original evolutionary path, i.e. return to aquatic life after a terrestrial phase. The rare reports concerning visual laterality of marine mammals investigated mainly discrimination processes. As dolphins are migrant species they are confronted to a changing environment. Being able to categorize new versus familiar objects would allow dolphins a rapid adaptation to novel environments. Visual laterality could be a prerequisite to this adaptability. To date, no study, to our knowledge, has analyzed the environmental factors that could influence their visual laterality. Results We investigated visual laterality expressed spontaneously at the water surface by a group of five common bottlenose dolphins (Tursiops truncatus in response to various stimuli. The stimuli presented ranged from very familiar objects (known and manipulated previously to familiar objects (known but never manipulated to unfamiliar objects (unknown, never seen previously. At the group level, dolphins used their left eye to observe very familiar objects and their right eye to observe unfamiliar objects. However, eyes are used indifferently to observe familiar objects with intermediate valence. Conclusion Our results suggest different visual cerebral processes based either on the global shape of well-known objects or on local details of unknown objects. Moreover, the manipulation of an object appears necessary for these dolphins to construct a global representation of an object enabling its immediate categorization for subsequent use. Our experimental results pointed out some cognitive capacities of dolphins which might be crucial for their wild life given their

  12. 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.

  13. Visual laterality in dolphins: importance of the familiarity of stimuli.

    Science.gov (United States)

    Blois-Heulin, Catherine; Crével, Mélodie; Böye, Martin; Lemasson, Alban

    2012-01-12

    Many studies of cerebral asymmetries in different species lead, on the one hand, to a better understanding of the functions of each cerebral hemisphere and, on the other hand, to develop an evolutionary history of hemispheric laterality. Our animal model is particularly interesting because of its original evolutionary path, i.e. return to aquatic life after a terrestrial phase. The rare reports concerning visual laterality of marine mammals investigated mainly discrimination processes. As dolphins are migrant species they are confronted to a changing environment. Being able to categorize new versus familiar objects would allow dolphins a rapid adaptation to novel environments. Visual laterality could be a prerequisite to this adaptability. To date, no study, to our knowledge, has analyzed the environmental factors that could influence their visual laterality. We investigated visual laterality expressed spontaneously at the water surface by a group of five common bottlenose dolphins (Tursiops truncatus) in response to various stimuli. The stimuli presented ranged from very familiar objects (known and manipulated previously) to familiar objects (known but never manipulated) to unfamiliar objects (unknown, never seen previously). At the group level, dolphins used their left eye to observe very familiar objects and their right eye to observe unfamiliar objects. However, eyes are used indifferently to observe familiar objects with intermediate valence. Our results suggest different visual cerebral processes based either on the global shape of well-known objects or on local details of unknown objects. Moreover, the manipulation of an object appears necessary for these dolphins to construct a global representation of an object enabling its immediate categorization for subsequent use. Our experimental results pointed out some cognitive capacities of dolphins which might be crucial for their wild life given their fission-fusion social system and migratory behaviour.

  14. 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

  15. 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.

  16. 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.

  17. Visual fatigue while watching 3D stimuli from different positions.

    Science.gov (United States)

    Aznar-Casanova, J Antonio; Romeo, August; Gómez, Aurora Torrents; Enrile, Pedro Martin

    When observers focus their stereoscopic visual system for a long time (e.g., watching a 3D movie) they may experience visual discomfort or asthenopia. We tested two types of models for predicting visual fatigue in a task in which subjects were instructed to discriminate between 3D characters. One model was based on viewing distance (focal distance, vergence distance) and another in visual direction (oculomotor imbalance). A 3D test was designed to assess binocular visual fatigue while looking at 3D stimuli located in different visual directions and viewed from two distances from the screen. The observers were tested under three conditions: (a) normal vision; (b) wearing a lens (-2 diop.); (c) wearing a base-out prism (2▿) over each eye. Sensitivity and specificity were calculated (as Signal Detection Theory parameters: SDT). An ANOVA and SDT analyses revealed that impaired visual performance were directly related to short distance and larger deviation in visual direction, particularly when the stimuli were located nearer and at more than 24° to the centre of the screen in dextroversion and beyond. This results support a mixed model, combining a model based on the visual angle (related to viewing distance) and another based on the oculomotor imbalance (related to visual direction). This mixed model could help to predict the distribution of seats in the cinema room ranging from those that produce greater visual comfort to those that produce more visual discomfort. Also could be a first step to pre-diagnosis of binocular vision disorders. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  18. Acute Effects of Alcohol on Encoding and Consolidation of Memory for Emotional Stimuli.

    Science.gov (United States)

    Weafer, Jessica; Gallo, David A; de Wit, Harriet

    2016-01-01

    Acute doses of alcohol impair memory when administered before encoding of emotionally neutral stimuli but enhance memory when administered immediately after encoding, potentially by affecting memory consolidation. Here, we examined whether alcohol produces similar biphasic effects on memory for positive or negative emotional stimuli. The current study examined memory for emotional stimuli after alcohol (0.8 g/kg) was administered either before stimulus viewing (encoding group; n = 20) or immediately following stimulus viewing (consolidation group; n = 20). A third group received placebo both before and after stimulus viewing (control group; n = 19). Participants viewed the stimuli on one day, and their retrieval was assessed exactly 48 hours later, when they performed a surprise cued recollection and recognition test of the stimuli in a drug-free state. As in previous studies, alcohol administered before encoding impaired memory accuracy, whereas alcohol administered after encoding enhanced memory accuracy. Critically, alcohol effects on cued recollection depended on the valence of the emotional stimuli: Its memory-impairing effects during encoding were greatest for emotional stimuli, whereas its memory-enhancing effects during consolidation were greatest for emotionally neutral stimuli. Effects of alcohol on recognition were not related to stimulus valence. This study extends previous findings with memory for neutral stimuli, showing that alcohol differentially affects the encoding and consolidation of memory for emotional stimuli. These effects of alcohol on memory for emotionally salient material may contribute to the development of alcohol-related problems, perhaps by dampening memory for adverse consequences of alcohol consumption.

  19. 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.

  20. Influence of affective auditory stimuli on balance control during static stance.

    Science.gov (United States)

    Chen, Xingyu; Qu, Xingda

    2017-03-01

    The main purpose of this study was to examine the effects of affective auditory stimuli on balance control during static stance. Twelve female and 12 male participants were recruited. Each participant completed four upright standing trials including three auditory stimuli trials and one baseline trial (ie no auditory stimuli). The three auditory stimuli trials corresponded to the pleasant, neutral and unpleasant sound conditions. Center of pressure (COP) measures were used to quantify balance control performance. It was found that unpleasant auditory stimuli were associated with larger COP amplitude in the AP direction compared to the rest testing conditions. There were no significant interaction effects between 'auditory stimuli' and gender. These findings suggested that some specificities presented by auditory stimuli are important for balance control, and the effects of auditory stimuli on balance control were dependent on their affective components. Practitioner Summary: Findings from this study can aid in better understanding of the relationship between auditory stimuli and balance control. In particular, unpleasant auditory stimuli were found to result in poorer balance control and higher fall risks. Therefore, to prevent fall accidents, interventions should be developed to reduce exposures to unpleasant sound.

  1. Perceived duration of visual and tactile stimuli depends on perceived speed

    Directory of Open Access Journals (Sweden)

    Alice eTomassini

    2011-09-01

    Full Text Available It is known that the perceived duration of visual stimuli is strongly influenced by speed: faster moving stimuli appear to last longer. To test whether this is a general property of sensory systems we asked participants to reproduce the duration of visual and tactile gratings, and visuo-tactile gratings moving at a variable speed (3.5 – 15 cm/s for three different durations (400, 600 and 800 ms. For both modalities, the apparent duration of the stimulus increased strongly with stimulus speed, more so for tactile than for visual stimuli. In addition, visual stimuli were perceived to last approximately 200 ms longer than tactile stimuli. The apparent duration of visuo-tactile stimuli lay between the unimodal estimates, as the Bayesian account predicts, but the bimodal precision of the reproduction did not show the theoretical improvement. A cross-modal speed-matching task revealed that visual stimuli were perceived to move faster than tactile stimuli. To test whether the large difference in the perceived duration of visual and tactile stimuli resulted from the difference in their perceived speed, we repeated the time reproduction task with visual and tactile stimuli matched in apparent speed. This reduced, but did not completely eliminate the difference in apparent duration. These results show that for both vision and touch, perceived duration depends on speed, pointing to common strategies of time perception.

  2. 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

    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...... 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...... 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...

  3. Contractor firm strategies in delivering green project: A review

    Science.gov (United States)

    Powmya, Ayisha; Abidin, Nazirah Zainul; Azizi, Nurul Sakina Mokhtar

    2017-10-01

    Building green requires effort from various parties, from those who plan, design, manage and construct the building. Contractors are responsible for converting the design on paper into a real building and their role at the construction site support environmental sustainability by implementing responsible construction practices. Inefficient or inexperienced contractor in green construction project may find that delivering this type of project is not an easy task due to added requirement in design, stringent practices at site and the use of green technology and materials. Adopting suitable strategies at firm level will assist in preparatory process and readiness of delivering the green project. This paper reviews the strategies at firm level to deliver green construction project. From extensive literature review, it was discovered that there are six strategies to be adopted by the contractor. Understanding these strategies is expected to promote more contractors to be proactive in delivering green projects.

  4. 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.

  5. Expert assessment concludes negative emissions scenarios may not deliver

    OpenAIRE

    Vaughan, Naomi E; Gough, Clair

    2016-01-01

    Many integrated assessment models (IAMs) rely on the availability and extensive use of biomass energy with carbon capture and storage (BECCS) to deliver emissions scenarios consistent with limiting climate change to below 2 °C average temperature rise. BECCS has the potential to remove carbon dioxide (CO2) from the atmosphere, delivering ‘negative emissions’. The deployment ofBECCS at the scale assumed in IAM scenarios is highly uncertain: biomass energy is commonly used but not at such a sca...

  6. Evaluating conditioning of related and unrelated stimuli using a compound test.

    Science.gov (United States)

    Rescorla, Robert A

    2008-05-01

    Three experiments used a compound test procedure to evaluate whether superior conditioning results from the pairing of stimuli that are related to each other. In each case, a stimulus compound was tested after its component conditioned stimuli (CSs) had been conditioned by the same unconditioned stimuli (USs) arranged such that either related or unrelated CSs and USs were paired. Experiment 1 explored auditory and gustatory stimuli conditioned by LiCl or shock, using rats. Experiments 2 and 3 used second-order conditioning in pigeons to pair stimuli that were similar by virtue either of qualitative features or of shared physical location. In each case, the compound test provided clear evidence that pairing related stimuli produces superior associative learning.

  7. P1 and N170 components distinguish human-like and animal-like makeup stimuli.

    Science.gov (United States)

    Luo, Shuwei; Luo, Wenbo; He, Weiqi; Chen, Xu; Luo, Yuejia

    2013-06-19

    This study used event-related potentials to investigate the sensitivity of P1 and N170 components to human-like and animal-like makeup stimuli, which were derived from pictures of Peking opera characters. As predicted, human-like makeup stimuli elicited larger P1 and N170 amplitudes than did animal-like makeup stimuli. Interestingly, a right hemisphere advantage was observed for human-like but not for animal-like makeup stimuli. Dipole source analyses of 130-200-ms window showed that the bilateral fusiform face area may contribute to the differential sensitivity of the N170 component in response to human-like and animal-like makeup stimuli. The present study suggests that the amplitudes of both the P1 and the N170 are sensitive for the mouth component of face-like stimuli.

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

    OpenAIRE

    Tetsuya eAsakawa; Ayumi eMuramatsu; Takuto eHayashi; Tatsuya eUrata; Masato eTaya; Yuko eMizuno-Matsumoto

    2014-01-01

    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 (p...

  9. The Detection of Fear-Relevant Stimuli: Are Guns Noticed as Quickly as Snakes?

    OpenAIRE

    Fox, Elaine; Griggs, Laura; Mouchlianitis, Elias

    2007-01-01

    Potentially dangerous stimuli are important contenders for the capture of visual–spatial attention, and it has been suggested that an evolved fear module is preferentially activated by stimuli that are fear relevant in a phylogenetic sense (e.g., snakes, spiders, angry faces). In this study, a visual search task was used to test this hypothesis by directly contrasting phylogenetically (snakes) and ontogenetically (guns) fear-relevant stimuli. Results showed that the modern threat was detected...

  10. Relationship of diagnostic, demographic, and personality variables to self-reported stimuli for chemical use.

    Science.gov (United States)

    Allen, J P; Faden, V; Rawlings, R

    1992-01-01

    While extensive research has been conducted to determine internal and external stimuli for drinking by alcoholics, the topic of how demographic, diagnostic, and personality variables may relate to these precipitants is largely unexplored. This study suggests that stimuli to use alcohol or drugs differ partly as a function of diagnosis (alcohol dependence vs. concurrent alcohol and drug dependence). Age, education, and gender do not appear related to the stimuli in either diagnostic group. Personality characteristics of cognitive reflectiveness, impulse control, sociability, and intrapunitiveness, however, seem to be associated with certain classes of high risk stimuli.

  11. A Safe Haven: Investigating Social-Support Figures as Prepared Safety Stimuli.

    Science.gov (United States)

    Hornstein, Erica A; Fanselow, Michael S; Eisenberger, Naomi I

    2016-08-01

    Although fear-conditioning research has demonstrated that certain survival-threatening stimuli, namely prepared fear stimuli, are readily associated with fearful events, little research has explored whether a parallel category exists for safety stimuli. We examined whether social-support figures, who have typically benefited survival, can serve as prepared safety stimuli, a category that has not been explored previously. Across three experiments, we uncovered three key findings. First, social-support figures were less readily associated with fear than were strangers or neutral stimuli (in a retardation-of-acquisition test). Second, social-support stimuli inhibited conditional fear responses to other cues (in a summation test), and this inhibition continued even after the support stimulus was removed. Finally, these effects were not simply due to familiarity or reward because both familiar and rewarding stimuli were readily associated with fear, whereas social-support stimuli were not. These findings suggest that social-support figures are one category of prepared safety stimuli that may have long-lasting effects on fear-learning processes. © The Author(s) 2016.

  12. Biodegradable 'intelligent' materials in response to chemical stimuli for biomedical applications.

    Science.gov (United States)

    Ju, Xiao-Jie; Xie, Rui; Yang, Lihua; Chu, Liang-Yin

    2009-05-01

    Biodegradable stimuli-responsive materials, which exhibit large and sharp physical-chemical changes in response to small physical or chemical stimuli, are attracting increasing interests because of their potential applications in biomedical fields, such as transient implants, drug delivery carriers, and tissue engineering scaffolds. Our previous review (see page 493 of issue 4) summarized those biodegradable 'intelligent' materials that respond to physical stimuli, such as temperature, ultrasound, and magnetic field. Biodegradable 'intelligent' materials that could respond to chemical stimuli, such as pH and specific molecules, have also been studied intensively and significant progress in this field has been achieved. As a single stimulus-responsive property would limit practical application, multi-stimuli-responsive materials are receiving increasing interest and considerable attention. This review summarizes the development of biodegradable 'intelligent' materials in response to chemical stimuli and to dual stimuli; their potential biomedical applications are also introduced. A detailed analysis of publications and patents on such materials in recent years is presented. Most of biodegradable stimuli-responsive materials are currently still at a developmental research stage. Further work is required to improve the responsive properties between the materials and the biological environments, so that the clinical applicability of such devices could be successful. We hope that our review will be helpful in the future development of new stimuli-responsive biodegradable polymers or polymeric systems that can be used reliably in real-life applications.

  13. 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.

  14. The Effect of Attention on Neuronal Responses to High and Low Contrast Stimuli

    Science.gov (United States)

    Lee, Joonyeol

    2010-01-01

    It remains unclear how attention affects the tuning of individual neurons in visual cerebral cortex. Some observations suggest that attention preferentially enhances responses to low contrast stimuli, whereas others suggest that attention proportionally affects responses to all stimuli. Resolving how attention affects responses to different stimuli is essential for understanding the mechanism by which it acts. To explore the effects of attention on stimuli of different contrasts, we recorded from individual neurons in the middle temporal visual area (MT) of rhesus monkeys while shifting their attention between preferred and nonpreferred stimuli within their receptive fields. This configuration results in robust attentional modulation that makes it possible to readily distinguish whether attention acts preferentially on low contrast stimuli. We found no evidence for greater enhancement of low contrast stimuli. Instead, the strong attentional modulations were well explained by a model in which attention proportionally enhances responses to stimuli of all contrasts. These data, together with observations on the effects of attention on responses to other stimulus dimensions, suggest that the primary effect of attention in visual cortex may be to simply increase the strength of responses to all stimuli by the same proportion. PMID:20538780

  15. 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.

  16. Controlled release from stimuli-sensitive microgel capsules

    Science.gov (United States)

    Masoud, Hassan; Alexeev, Alexander

    2011-10-01

    We introduce a mesoscale computational model for responsive gels, i.e. chemically cross-linked polymer networks immersed in Newtonian fluids, and use it to probe the release of nanoparticles from hollow microgel capsules that swell and deswell in response to external stimuli. Our model explicitly describes the transport of nanoparticles in swelling/deswelling polymer networks with complex geometries and associated fluid flows. Our simulations reveal that responsive microcapsules can be effectively utilized for steady and pulsatile release of encapsulated solutes. Steady, diffusive release of nanoparticle takes place from swollen gel capsules, whereas capsule deswelling cause burst-like discharge of solutes driven by a flow from the shrinking capsule interior. We demonstrate that this hydrodynamic release can be regulated by introducing rigid microscopic rods inside the capsule. Our calculations indicate that the rods stretch the deswelling membrane and promote the formation of large pores in the shell, which allow massive flow-driven release of nanoparticles. Thus, our findings unveil a new approach for regulating the release from stimulus responsive micro-carriers that will be especially useful for designing new drug delivery systems.

  17. Transition Towards Performance Based Oversight - Stimuli and effects

    Directory of Open Access Journals (Sweden)

    Tomáš Duša

    2013-05-01

    Full Text Available This paper talks about a new trend in supervising aviation organisations by aviation authorities. It wants to explain the need of transition from compliance based oversight towards performance based oversight.Aviation regulations define the set of strict rules, which must be followed very closely, no exemptions are accepted. This is a very useful tool, that significantly improves safety especially in last decades. However, aviation evolves into very complex and extensive field that is hard to control as a whole. This fact has brought some difficulties, that finally act as stimuli for introduction novel oversight principles. There must be established some flexibility and introduced some objectives, instead of strict directives. Each subject shall reach them by its own way. Setting up the margins and focussing towards the safety objectives are the essential parts of, so called “Performance Based attitude”. Performance Based gives a new form of flexibility in managing safety, which is undeniably needed to handle a complex aviation system.Each transition is accompanied by many changes, transition towards PBO is not an exception either. Even the small impulse could lead towards many changes within the complexity of networked aviation safety elements. This paper wants to attract the view towards these effects as well.

  18. 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.

  19. 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.

  20. Perception of facial attractiveness from static and dynamic stimuli.

    Science.gov (United States)

    Kościński, Krzysztof

    2013-01-01

    Although people we meet in real life are usually seen in motion, research on facial attractiveness has predominantly been conducted on static facial images. This raises a question about ecological validity of results obtained in such studies. Recently, several studies endeavoured to determine the concordance between attractiveness of faces seen on photos and video clips, but their results are markedly divergent, frequently indicating no concordance. In the present study, the association between attractiveness of facial images and clips was tested on a larger sample than has previously been reported (106 females, 102 males), and features under the face owner's control (scalp and facial hair, makeup, mouth expression) were controlled for. Two types of facial images were used: photographs and frames extracted from films. Correlation coefficients between attractiveness of static and dynamic faces were high (about 0.7), did not depend on facial sex or image type (photograph/frame), and did not diminish when the covariates were controlled for. Furthermore, the importance of facial averageness, femininity/ masculinity, symmetry, fattiness, skin health, and mouth expression for attractiveness proved similar for static and dynamic stimuli. This leads to the optimistic conclusion that results of studies relying on attractiveness assessments of static facial images are ecologically valid.

  1. 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.

  2. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Kröger, Inga L; May, Arne

    2014-09-09

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

  4. Recency and suffix effects with immediate recall of olfactory stimuli.

    Science.gov (United States)

    Miles, C; Jenkins, R

    2000-05-01

    In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.

  5. 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)

  6. Sensory sensitivity and identification and hedonic assessment ofolfactory stimuli

    Directory of Open Access Journals (Sweden)

    Borys Ruszpel

    2012-06-01

    Full Text Available Conducted research had an exploratory character. It was focused on connections between temperament and olfactory functioning – in particular, identification and affective assessment of olfactory stimuli. Main research question dealt with potential correlations between sensory sensitivity (dimension of temperamental questionnaire FCZ‑KT with declarative and objective ability to identify presented odours and their assessment. Fifty four schoolgirls from one of the Warsaw sec‑ ondary schools participated in the research and they were asked for filling in the FCZ‑KT questionnaire and evaluating each of 16 smell samples. Analyses revealed a significant positive correlation between declared familiarity and accurate odours’ identification (odours that were subjectively known were recognized more accurately than unknown and a posi‑ tive correlation between declared familiarity and affective assessment (odours that were known were assessed as more pleasant than unknown. Sensory sensitivity was not correlated neither with declarative nor real ability to identify smells, however sensory sensitivity was positively correlated with affective assessment (the higher scores on sensory sensitivity dimension, the more pleasantly assessed odours in general. Analyses revealed a number of connections between other dimensions of FCZ‑KT questionnaire (perseverance, liveliness, stamina and the ability (both objective and subjective to correctly identify odours which were most difficult to recognize. Completed project might be perceived as a starting point for further research concerning relationships between temperament, olfactory functioning, and food preferences among patients diagnosed with eating disorders such as anorexia nervosa, bulimia nervosa, and obesity.

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

    Directory of Open Access Journals (Sweden)

    Lili Wu

    Full Text Available 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.

  8. Hypnotically induced somatosensory alterations: Toward a neurophysiological understanding of hypnotic anaesthesia.

    Science.gov (United States)

    Zeev-Wolf, Maor; Goldstein, Abraham; Bonne, Omer; Abramowitz, Eitan G

    2016-07-01

    Whereas numerous studies have investigated hypnotic analgesia, few have investigated hypnotic anaesthesia. Using magnetoencephalography (MEG) we investigated and localized brain responses (event-related fields and oscillatory activity) during sensory processing under hypnotic anaesthesia. Nineteen right handed neurotypical individuals with moderate-to-high hypnotizability received 100 vibrotactile stimuli to right and left index fingers in a random sequence. Thereafter a hypnotic state was induced, in which anaesthetic suggestion was applied to the left hand only. Once anaesthetic suggestion was achieved, a second, identical, session of vibrotactile stimuli was commenced. We found greater brain activity in response to the stimuli delivered to the left (attenuated) hand before hypnotic anaesthesia, than under hypnotic anaesthesia, in both the beta and alpha bands. In the beta band, the reduction of activity under hypnotic anaesthesia was found around 214-413ms post-stimuli and was located mainly in the right insula. In the alpha band, it was found around 253-500ms post-stimuli and was located mainly in the left inferior frontal gyrus. In a second experiment, attention modulation per se was ruled out as the underlying cause of the effects found. These findings may suggest that the brain mechanism underlying hypnotic anaesthesia involves top-down somatosensory inhibition and, therefore, a reduction of somatosensory awareness. The result of this mechanism is a mental state in which individuals lose bodily sensation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. [Exploring the effectiveness of a health education program on the stimuli frame and on uncertainty in patients with sudden hearing loss].

    Science.gov (United States)

    Lee, Ya-Hui; Wang, Huey-Ling; Li, Chung-Yi; Shiao, An-Suey; Tu, Tzong-Yang

    2014-06-01

    Uncertainty may limit communication and affect the ability of patients to adapt to their illness. A high level of uncertainty in patients concurrent with sudden hearing loss has been related to poor comprehension of communications and poor illness understanding. Currently, there is no any certain standard information sheet in the clinical setting. This study evaluates the effect of a one-to-one oral instruction strategy combined with an information sheet firstly on the stimuli frame and then on uncertainty in patients suffering from idiopathic sudden sensorineural hearing loss. An experimental design was employed and 60 patients were randomly assigned to either the experimental group (n=28) or the control group (n=32). A structured questionnaire that included the stimuli frame of uncertainty and the Mishel uncertainty illness scale was used to collect data. All samples received regular care following admission to the hospital and received the pretest within 24 hours after admission. The experimental group received the one-to-one oral instruction strategy combined with an information sheet immediately after the pretest. All participants completed the posttest three days later. The health education program increased perceived understanding of illness in patients with the sudden hearing loss, and reduced their illness uncertainty. Perceived understanding of illness was negatively related to the level of illness uncertainty. The stimuli frame of uncertainty acted as a mediator between the intervention and the uncertainty. The intervention increased the level of cognition of the stimuli frame of uncertainty and then indirectly lowered the uncertainty level. These findings support the effectiveness of the individual health education strategy with the information sheet in delivering to patients critical information about their condition and treatment. Moreover, this intervention may effectively increase illness cognition and reduce uncertainty in patients with sudden

  10. Broadband noise masks suppress neural responses to narrowband stimuli

    Directory of Open Access Journals (Sweden)

    Daniel Hart Baker

    2014-07-01

    Full Text Available White pixel noise is widely used to estimate the level of internal noise in a system by injecting external variance into the detecting mechanism. Recent work (Baker & Meese, 2012, J Vis, 12(10:20 has provided psychophysical evidence that such noise masks might also cause suppression that could invalidate estimates of internal noise. Here we measure neural population responses directly, using steady-state visual evoked potentials, elicited by target stimuli embedded in different mask types. Sinusoidal target gratings of 1c/deg flickered at 5Hz, and were shown in isolation, or with superimposed orthogonal grating masks or 2D white noise masks, flickering at 7Hz. Compared with responses to a blank screen, the Fourier amplitude at the target frequency increased monotonically as a function of target contrast when no mask was present. Both orthogonal and white noise masks caused rightward shifts of the contrast response function, providing evidence of contrast gain control suppression. We also calculated within-observer amplitude variance across trials. This increased in proportion to the target response, implying signal-dependent (i.e. multiplicative noise at the system level, the implications of which we discuss for behavioural tasks. This measure of variance was reduced by both mask types, consistent with the changes in mean target response. An alternative variety of noise, which we term zero-dimensional noise, involves trial-by-trial jittering of the target contrast. This type of noise produced no gain control suppression, and increased the amplitude variance across trials.

  11. 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

  12. 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.

  13. Pain by Association? Experimental Modulation of Human Pain Thresholds Using Classical Conditioning.

    Science.gov (United States)

    Madden, Victoria J; Bellan, Valeria; Russek, Leslie N; Camfferman, Danny; Vlaeyen, Johan W S; Moseley, G Lorimer

    2016-10-01

    A classical conditioning framework is often used for clinical reasoning about pain that persists after tissue healing. However, experimental studies demonstrating classically conditioned pain in humans are lacking. The current study tested whether non-nociceptive somatosensory stimuli can come to modulate pain thresholds after being paired with painful nociceptive stimuli in healthy humans. We used a differential simultaneous conditioning paradigm in which one nonpainful vibrotactile conditioned stimulus (CS(+)) was simultaneously paired with an unconditioned painful laser stimulus, and another vibrotactile stimulus (CS(-)) was paired with a nonpainful laser stimulus. After acquisition, at-pain-threshold laser stimuli were delivered simultaneously with a CS(+) or CS(-) vibrotactile stimulus. The primary outcome was the percentage of at-threshold laser stimuli that were reported as painful. The results were as expected: after conditioning, at-threshold laser trials paired with the CS(+) were reported as painful more often, as more intense, and as more unpleasant than those paired with the CS(-). This study provides new evidence that pain thresholds can be modulated via classical conditioning, even when the stimulus used to test the threshold cannot be anticipated. As such, it lays a critical foundation for further investigations of classical conditioning as a possible driver of persistent pain. This study provides new evidence that human pain thresholds can be influenced by non-nociceptive somatosensory stimuli, via a classical conditioning effect. As such, it lays a critical foundation for further investigations of classical conditioning as a possible driver of persistent pain. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  14. Delivering Faster Congestion Feedback with the Mark-Front Strategy

    Science.gov (United States)

    Liu, Chunlei; Jain, Raj

    2001-01-01

    Computer networks use congestion feedback from the routers and destinations to control the transmission load. Delivering timely congestion feedback is essential to the performance of networks. Reaction to the congestion can be more effective if faster feedback is provided. Current TCP/IP networks use timeout, duplicate Acknowledgement Packets (ACKs) and explicit congestion notification (ECN) to deliver the congestion feedback, each provides a faster feedback than the previous method. In this paper, we propose a markfront strategy that delivers an even faster congestion feedback. With analytical and simulation results, we show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Keywords: Explicit Congestion Notification, mark-front, congestion control, buffer size requirement, fairness.

  15. Meeting the challenges: delivering interactive stoma care education.

    Science.gov (United States)

    Lee, Janice; Moore, Hazel; Asbury, Nicky

    2008-04-01

    This article illustrates how the authors used the following frameworks: audit cycle, clinical governance, essence of care and evaluations to create a fun, interactive and transferable method of delivering an education programme in the workplace environment. The article demonstrates the benefits of using action planning, benchmarking and overcoming difficulties in delivering education across two organizational boundaries (primary and secondary care). 'Today's 6 x 30 minute Stoma Challenges are...' a full and fun afternoon of interactive stoma education for primary and secondary care staff delivered in an innovative and creative way. The main objective is to enhance qualified and unqualified nurses existing knowledge and skills in relation to stoma care. Also encouraging staff development therefore enhancing the patients' experiences regardless of whether they are in a primary or secondary care setting.

  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. 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…

  18. 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.

  19. Control by Contextual Stimuli in Novel Second-Order Conditional Discriminations

    Science.gov (United States)

    Perez-Gonzalez, Luis Antonio; Martinez, Hector

    2007-01-01

    Eighteen undergraduates participated in studies designed to examine the factors that produce transfer of contextual functions to novel stimuli in second-order conditional discriminations. In Study 1, participants selected comparison B1 given sample A1 and comparison B2 given sample A2 in a matching-to-sample procedure. Contextual stimuli X1 or X2…

  20. Pupillary Reactivity to Emotional Stimuli in Children of Depressed and Anxious Mothers

    Science.gov (United States)

    Burkhouse, Katie L.; Siegle, Greg J.; Gibb, Brandon E.

    2014-01-01

    Background: The primary aim of this study was to examine differences in physiological reactivity (measured via pupillometry) to emotional stimuli between children of depressed versus nondepressed mothers. A second goal was to examine differences in pupil dilation to emotional stimuli between children of anxious versus nonanxious mothers. Method:…

  1. Biodegradable 'intelligent' materials in response to physical stimuli for biomedical applications.

    Science.gov (United States)

    Ju, Xiao-Jie; Xie, Rui; Yang, Lihua; Chu, Liang-Yin

    2009-04-01

    Stimuli-responsive materials that undergo dramatic changes in physical-chemical properties in response to mild physical changes in environmental conditions are attracting increasing interest because of their potential application in biomedical fields. Biodegradable materials are highly desired for most biomedical applications in vivo, such as transient implants, drug-delivery carriers, and tissue engineering scaffolds. Biomedical systems that are both biodegradable and stimuli-responsive have therefore been studied intensively and significant progress in this field has been achieved. This review summarizes the development of biodegradable 'intelligent' materials in response to physical stimuli and their potential biomedical applications. A detailed analysis of publications and patents on such materials in recent years is presented. Although biodegradable stimuli-responsive materials are highly attractive for biomedical applications, most such materials are currently at a developmental research stage. Additionally, single stimulus-responsive property limits the practical applications of these materials. To achieve more favorable applications for these materials, further efforts are still necessary, especially for developing multi-stimuli-responsive functions of materials and improving the stimuli-responsive properties of such materials in a biological environment. Bearing in mind the great prospect of these biodegradable stimuli-responsive materials, we hope that this review will help in the future development of stimuli-responsive polymers or systems that could be reliably employed in biomedical applications.

  2. Attentional bias for positive emotional stimuli: A meta-analytic investigation.

    Science.gov (United States)

    Pool, Eva; Brosch, Tobias; Delplanque, Sylvain; Sander, David

    2016-01-01

    Despite an initial focus on negative threatening stimuli, researchers have more recently expanded the investigation of attentional biases toward positive rewarding stimuli. The present meta-analysis systematically compared attentional bias for positive compared with neutral visual stimuli across 243 studies (N = 9,120 healthy participants) that used different types of attentional paradigms and positive stimuli. Factors were tested that, as postulated by several attentional models derived from theories of emotion, might modulate this bias. Overall, results showed a significant, albeit modest (Hedges' g = .258), attentional bias for positive as compared with neutral stimuli. Moderator analyses revealed that the magnitude of this attentional bias varied as a function of arousal and that this bias was significantly larger when the emotional stimulus was relevant to specific concerns (e.g., hunger) of the participants compared with other positive stimuli that were less relevant to the participants' concerns. Moreover, the moderator analyses showed that attentional bias for positive stimuli was larger in paradigms that measure early, rather than late, attentional processing, suggesting that attentional bias for positive stimuli occurs rapidly and involuntarily. Implications for theories of emotion and attention are discussed. (c) 2015 APA, all rights reserved).

  3. Effects of Social Stimuli on Laughing and Smiling in Young Children with Angelman Syndrome

    Science.gov (United States)

    Richman, David M.; Gernat, Eric; Teichman, Heather

    2006-01-01

    The effects of social stimuli present and absent on laughing and smiling in 2 young children with Angelman syndrome were assessed via a multielement design. Results indicated that laughing and smiling for either child was unaffected by the social stimuli assessed in the social interaction condition. Results are discussed in terms of the effects of…

  4. Effects of spatial separation between stimuli in whole report from brief visual displays

    DEFF Research Database (Denmark)

    Kyllingsbæk, Søren; Valla, Christian; Vanrie, Jan

    2007-01-01

    Direct measurements of effects of spatial separation between stimuli in whole report from brief visual displays are reported. The stimuli were presented on the periphery of an imaginary circle centered on fixation. In Experiment 1, each display showed 2 capital letters (letter height = 1.3°, widt...

  5. 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…

  6. Are Attractive Men's Faces Masculine or Feminine? The Importance of Type of Facial Stimuli

    Science.gov (United States)

    Rennels, Jennifer L.; Bronstad, P. Matthew; Langlois, Judith H.

    2008-01-01

    The authors investigated whether differences in facial stimuli could explain the inconsistencies in the facial attractiveness literature regarding whether adults prefer more masculine- or more feminine-looking male faces. Their results demonstrated that use of a female average to dimorphically transform a male facial average produced stimuli that…

  7. 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.

  8. Direction of stimulus movement alters fear-linked individual differences in attentional vigilance to spider stimuli.

    Science.gov (United States)

    Basanovic, Julian; Dean, Laurence; Riskind, John H; MacLeod, Colin

    2017-12-01

    Researchers have proposed that high spider-fearful individuals are characterised by heightened attentional vigilance to spider stimuli, as compared to low spider-fearful individuals. However, these findings have arisen from methodologies that have uniformly employed only static stimuli. Such findings do not inform upon the patterns of fear-linked attentional selectivity that occur in the face of moving feared stimuli. Hence, the present study developed a novel methodology designed to examine the influence of stimulus movement on attentional vigilance to spider and non-spider stimuli. Eighty participants who varied in level of spider-fear completed an attentional-probe task that presented stimuli under two conditions. One condition presented stimuli that displayed an approaching movement, while the other condition presented stimuli that displayed a receding movement. Fear-linked heightened attentional vigilance was observed exclusively under the latter condition. These findings suggest that fear-linked attentional vigilance to spider stimuli does not represent a uniform characteristic of heightened spider-fear, but rather is influenced by stimulus context. The means by which these findings inform understanding of attentional mechanisms that characterise heightened spider-fear, and avenues for future research, are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. possible stimuli for social behaviour in three species of freshwater fish

    African Journals Online (AJOL)

    Shaw (1962) found that fish of similar size school, that a head-to-tail approach is important and that movement outweighs colour and species as far as visual stimuli are concerned (Mellldla). Apparently the lateral line organs are important in this respect. Hearing, taste and smell are not regarded as effective stimuli by Shaw, ...

  10. Trained and Derived Relations with Pictures versus Abstract Stimuli as Nodes

    Science.gov (United States)

    Arntzen, Erik; Lian, Torunn

    2010-01-01

    Earlier studies have shown divergent results concerning the use of familiar picture stimuli in demonstration of equivalence. In the current experiment, we trained 16 children to form three 3-member classes in a many-to-one training structure. Half of the participants were exposed first to a condition with all abstract stimuli and then to a…

  11. 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

  12. 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…

  13. Inhibitory control of socially relevant stimuli in children with high functioning autism

    NARCIS (Netherlands)

    Geurts, H.M.; Begeer, S.; Stockmann, 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

  14. The use of creative stimuli at early stages of industrial product innovation

    DEFF Research Database (Denmark)

    Howard, Thomas J.; Dekoninck, Elies A.; Culley, Steve J.

    2010-01-01

    ' ideas decreased rapidly, where 75% of the appropriate ideas in the first 30 min had been expressed after just 15 min. By introducing various forms of stimuli to the groups, the frequency of idea generation was maintained and in many cases increased. The stimuli were also shown to help generate more...

  15. Increased endoplasmic reticulum stress in mouse osteocytes with aging alters Cox-2 response to mechanical stimuli

    NARCIS (Netherlands)

    Chalil, S.; Jaspers, R.T.; Manders, R.J.; Klein-Nulend, J.; Bakker, A.D.; Deldicque, L.

    2015-01-01

    Aging reduces bone mass as well as the anabolic response of bone to mechanical stimuli, resulting in osteopenia. Endoplasmic reticulum (ER) stress impairs the response of myogenic cells to anabolic stimuli, and is involved in sarcopenia, but whether ER stress also contributes to osteopenia is

  16. Effects of (artificial) boar stimuli on uterine activity in estrous sows

    NARCIS (Netherlands)

    Gerritsen, R.; Langendijk, P.; Soede, N.M.; Kemp, B.

    2005-01-01

    This study aims to examine influences of specific boar stimuli on uterine activity in estrous sows, by comparing uterine activity in presence of a mature teaser boar and a robot boar with variable stimuli. Nineteen multiparous, cyclic, commercial crossbred sows were used. Intra-luminal uterine

  17. Delivering supplemental oxygen during sedation via a saliva ejector.

    Science.gov (United States)

    Milnes, Alan R

    2002-01-01

    Intraoperative oxygen supplementation to sedated children has been shown to prevent hemoglobin desaturations even in the presence of apnea during pediatric conscious sedation. Although many practitioners deliver supplemental oxygen via a nasal hood, this method is impractical and often unsuccessful if the child is a mouth breather, has moderate adenotonsillar hypertrophy or occasionally cries during treatment (at which time there will be mouth breathing). This paper describes a method in which the saliva ejector is used to deliver supplemental oxygen to sedated children while they are receiving dental treatment. The advantages of this method and suggestions for its successful application are also included.

  18. Attention and emotional responses to sexual stimuli and their relationship to sexual desire.

    Science.gov (United States)

    Prause, Nicole; Janssen, Erick; Hetrick, William P

    2008-12-01

    Little is known about why individuals vary in their levels of sexual desire. Information processing models, like Barlow's (Journal of Consulting and Clinical Psychology 54:140-148, 1986) model of sexual functioning, suggest that individuals with higher sexual desire attend more and respond with more pleasant emotions to sexual cues than individuals with lower levels of sexual desire. In this study, 69 participants (36 women, 33 men) completed a dot detection task measuring attention capture by sexual stimuli and a startle eyeblink modulation task indexing the valence of emotional response to affective stimuli. Participants with high levels of sexual desire were slower to detect targets in the dot detection task that replaced sexual images but did not differ in startle eyeblink responses to sexual stimuli. The results suggest that the amount of attention captured by sexual stimuli is a stronger predictor of a person's sexual desire level than the valence of the emotional responses elicited by such stimuli.

  19. Exposure is not enough: suppressing stimuli from awareness can abolish the mere exposure effect.

    Science.gov (United States)

    de Zilva, Daniel; Vu, Luke; Newell, Ben R; Pearson, Joel

    2013-01-01

    Passive exposure to neutral stimuli increases subsequent liking of those stimuli--the mere exposure effect. Because of the broad implications for understanding and controlling human preferences, the role of conscious awareness in mere exposure has received much attention. Previous studies have claimed that the mere exposure effect can occur without conscious awareness of the stimuli. In two experiments, we applied a technique new to the mere exposure literature, called continuous flash suppression, to expose stimuli for a controlled duration with and without awareness. To ensure the reliability of the awareness manipulation, awareness was monitored on a trial-by-trial basis. Our results show that under these conditions the mere exposure effect does not occur without conscious awareness. In contrast, only when participants were aware of the stimuli did exposure increase liking and recognition. Together these data are consistent with the idea that the mere exposure effect requires conscious awareness and has important implications for theories of memory and affect.

  20. 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.

  1. 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.

  2. The motor side of emotions: investigating the relationship between hemispheres, motor reactions and emotional stimuli.

    Science.gov (United States)

    Onal-Hartmann, Cigdem; Pauli, Paul; Ocklenburg, Sebastian; Güntürkün, Onur

    2012-05-01

    The aim of the present study was to analyze if the left hemisphere preferentially controls flexion responses toward positive stimuli, while the right hemisphere is specialized toward extensor responses to negative pictures. To this end, right-handed subjects had to pull or push a joystick subsequent to seeing a positive or a negative stimulus in their left or right hemifield. Flexion responses were faster for positive stimuli, while negative stimuli were associated with faster extensions responses. Overall, performance was fastest when emotional stimuli were presented to the left visual hemifield. This right hemisphere superiority was especially clear for negative stimuli, while reaction times toward positive pictures showed no hemispheric difference. We did not find any interaction between hemifield and response type. Neither was there a triple interaction between valence, hemifield and response type. We suppose that response dichotomies in humans are not as tightly linked to a hemisphere- and valence-bound reaction type as previously assumed.

  3. 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.

  4. The detection of fear-relevant stimuli: are guns noticed as quickly as snakes?

    Science.gov (United States)

    Fox, Elaine; Griggs, Laura; Mouchlianitis, Elias

    2007-11-01

    Potentially dangerous stimuli are important contenders for the capture of visual-spatial attention, and it has been suggested that an evolved fear module is preferentially activated by stimuli that are fear relevant in a phylogenetic sense (e.g., snakes, spiders, angry faces). In this study, a visual search task was used to test this hypothesis by directly contrasting phylogenetically (snakes) and ontogenetically (guns) fear-relevant stimuli. Results showed that the modern threat was detected as efficiently as the more ancient threat. Thus, both guns and snakes attracted attention more effectively than neutral stimuli (flowers, mushrooms, and toasters). These results support a threat superiority effect but not one that is preferentially accessed by threat-related stimuli of phylogenetic origin. The results are consistent with the view that faster detection of threat in visual search tasks may be more accurately characterized as relevance superiority effects rather than as threat superiority effects.

  5. 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.

  6. Acute Effects of Alcohol on Encoding and Consolidation of Memory for Emotional Stimuli

    Science.gov (United States)

    Weafer, Jessica; Gallo, David A.; De Wit, Harriet

    2016-01-01

    Objective: Acute doses of alcohol impair memory when administered before encoding of emotionally neutral stimuli but enhance memory when administered immediately after encoding, potentially by affecting memory consolidation. Here, we examined whether alcohol produces similar biphasic effects on memory for positive or negative emotional stimuli. Method: The current study examined memory for emotional stimuli after alcohol (0.8 g/kg) was administered either before stimulus viewing (encoding group; n = 20) or immediately following stimulus viewing (consolidation group; n = 20). A third group received placebo both before and after stimulus viewing (control group; n = 19). Participants viewed the stimuli on one day, and their retrieval was assessed exactly 48 hours later, when they performed a surprise cued recollection and recognition test of the stimuli in a drug-free state. Results: As in previous studies, alcohol administered before encoding impaired memory accuracy, whereas alcohol administered after encoding enhanced memory accuracy. Critically, alcohol effects on cued recollection depended on the valence of the emotional stimuli: Its memory-impairing effects during encoding were greatest for emotional stimuli, whereas its memory-enhancing effects during consolidation were greatest for emotionally neutral stimuli. Effects of alcohol on recognition were not related to stimulus valence. Conclusions: This study extends previous findings with memory for neutral stimuli, showing that alcohol differentially affects the encoding and consolidation of memory for emotional stimuli. These effects of alcohol on memory for emotionally salient material may contribute to the development of alcohol-related problems, perhaps by dampening memory for adverse consequences of alcohol consumption. PMID:26751358

  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. Stimuli-sensitive nanoparticles for multiple anti-HIV microbicides

    Energy Technology Data Exchange (ETDEWEB)

    Giri, Namita; Oh, Byeongtaek; Lee, Chi H., E-mail: leech@umkc.edu [University of Missouri at Kansas City, Division of Pharmaceutical Sciences (United States)

    2016-05-15

    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{sup ®} (ES100{sup ®}), a pH-sensitive polymer. ES100{sup ®} 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{sup ®} NPs. The morphology of the ES100{sup ®} 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{sup ®} 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{sup ®} NPs had zeta potential in the range of −5 to −10 mV. In-vitro release studies displayed the potential benefits of ES100{sup ®} 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{sup ®} NPs did not exert any cytotoxicity individually or in a combination of both microbicides. TEER measurements confirmed that ES100{sup ®} 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{sup

  9. Heterogeneity reduces sensitivity of cell death for TNF-Stimuli

    Directory of Open Access Journals (Sweden)

    Schliemann Monica

    2011-12-01

    Full Text Available Abstract Background Apoptosis is a form of programmed cell death essential for the maintenance of homeostasis and the removal of potentially damaged cells in multicellular organisms. By binding its cognate membrane receptor, TNF receptor type 1 (TNF-R1, the proinflammatory cytokine Tumor Necrosis Factor (TNF activates pro-apoptotic signaling via caspase activation, but at the same time also stimulates nuclear factor κB (NF-κB-mediated survival pathways. Differential dose-response relationships of these two major TNF signaling pathways have been described experimentally and using mathematical modeling. However, the quantitative analysis of the complex interplay between pro- and anti-apoptotic signaling pathways is an open question as it is challenging for several reasons: the overall signaling network is complex, various time scales are present, and cells respond quantitatively and qualitatively in a heterogeneous manner. Results This study analyzes the complex interplay of the crosstalk of TNF-R1 induced pro- and anti-apoptotic signaling pathways based on an experimentally validated mathematical model. The mathematical model describes the temporal responses on both the single cell level as well as the level of a heterogeneous cell population, as observed in the respective quantitative experiments using TNF-R1 stimuli of different strengths and durations. Global sensitivity of the heterogeneous population was quantified by measuring the average gradient of time of death versus each population parameter. This global sensitivity analysis uncovers the concentrations of Caspase-8 and Caspase-3, and their respective inhibitors BAR and XIAP, as key elements for deciding the cell's fate. A simulated knockout of the NF-κB-mediated anti-apoptotic signaling reveals the importance of this pathway for delaying the time of death, reducing the death rate in the case of pulse stimulation and significantly increasing cell-to-cell variability. Conclusions Cell

  10. The Role of Universities in Supporting and Delivering Enterprise Education

    Science.gov (United States)

    Edwards, Louise-Jayne; Muir, Elizabeth J.

    2007-01-01

    While the academic debate has moved beyond the question of whether or not entrepreneurship can be taught and whether or not there is a need or demand for it, there is still considerable debate as to the most appropriate methods of delivering entrepreneurship education. This paper provides an overview of teaching strategies, pedagogies and methods…

  11. Essential medical laboratory services: their role in delivering ...

    African Journals Online (AJOL)

    This paper examines the establishment of Essential Medical Laboratory Services (EMLS) and their crucial role for delivering equitable health care to the poor population of Malawi as part of the Essential Health Package. We examine each of the major areas identified for intervention (maternal health, malaria, tuberculosis ...

  12. The Role of the Postgraduate Student in Delivering Bioscience Teaching

    Science.gov (United States)

    Scott, Jon; Maw, Stephen J.

    2009-01-01

    There has been much recent interest in the extent to which the teaching in higher education delivered by non-academic staff has increased in the recent past. Within the Biosciences there has always been a tradition of engaging postgraduate students to support the delivery of some forms of teaching. In this paper we report on the findings of a…

  13. Hepatitis B virus infection among pregnant women delivering at ...

    African Journals Online (AJOL)

    Objective: To determine the prevalence of hepatitis B virus (HBV) carrier and infectivity status among women delivering at Harare Maternity Hospital. Design: A serological survey study of pregnant women admitted for labour and delivery. Setting: Harare Maternity Hospital, Harare, Zimbabwe between June 1996 and June ...

  14. School Nurse-Delivered Adolescent Relationship Abuse Prevention

    Science.gov (United States)

    Raible, Claire A.; Dick, Rebecca; Gilkerson, Fern; Mattern, Cheryl S.; James, Lisa; Miller, Elizabeth

    2017-01-01

    Background: Project Connect is a national program to build partnerships among public health agencies and domestic violence services to improve the health care sector response to partner and sexual violence. Pennsylvania piloted the first school nurse-delivered adolescent relationship abuse intervention in the certified school nurses' office…

  15. Term tubal ectopic pregnancy delivered by laparotomy with a viable ...

    African Journals Online (AJOL)

    We describe an extremely rare medical phenomenon in a 28 year old who presented with undiagnosed tubal ectopic pregnancy at 41 weeks gestation and was delivered by laparotomy with linear salpingostomy at the Kenyatta National Hospital, Nairobi, Kenya. Key words: Term ectopic pregnancy, Ultrasound ...

  16. Health facility and health worker readiness to deliver new national ...

    African Journals Online (AJOL)

    Health facility and health worker readiness to deliver new national treatment policy for malaria in Kenya. ... Design: Cross-sectional survey. ... on the survey day, stock-outs in past six months, presence of AL wall charts, health worker\\'s exposure to in-service training on AL and access to new national malaria guidelines.

  17. Capacity to deliver pharmaceutical care by community pharmacies ...

    African Journals Online (AJOL)

    Pharmacy practice has transcended from largely a dispensary practice to pharmaceutical care practice. The capacity of community pharmacies to deliver pharmaceutical care was studied using pretested self survey methods. Ninety five percent (95%) of the respondents always educated customers on drug related needs, ...

  18. Pregnancy outcome among women who delivered in a secondary ...

    African Journals Online (AJOL)

    Pregnancy outcome among women who delivered in a secondary care hospital in ... 11(0.4%) maternal deaths with a maternal mortality ratio of 427 per 100,000 live births. ... There should be an improvement in the quality of care for obstetric ...

  19. Using technology to deliver quality education in Asia | IDRC ...

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

    2016-06-08

    Jun 8, 2016 ... An IDRC-funded project in Asia found that distance education can be as effective as traditional face-to-face education in delivering quality teaching and a good learning experience. This finding is particularly significant for remote and resource-poor regions in countries such as Mongolia and Cambodia.

  20. Foresight begins with FMEA. Delivering accurate risk assessments.

    Science.gov (United States)

    Passey, R D

    1999-03-01

    If sufficient factors are taken into account and two- or three-stage analysis is employed, failure mode and effect analysis represents an excellent technique for delivering accurate risk assessments for products and processes, and for relating them to legal liability. This article describes a format that facilitates easy interpretation.

  1. Unexplained massive subdural haematoma in a newborn delivered ...

    African Journals Online (AJOL)

    Emergency Caesarean Section (EmC/S) carried out after failed attempts at vaginal delivery may also be complicated by symptomatic SDH but spontaneous symptomatic SDH complicating Elective Caesarean Section (ElC/S) is a rarity. We describe a case of massive SDH in a term baby delivered by Elective C/S in the ...

  2. Hepatitis C virus seroprevalence among mothers delivering at the ...

    African Journals Online (AJOL)

    Hepatitis C virus seroprevalence among mothers delivering at the Korle-Bu Teaching Hospital, Ghana. ... AT Lassey, NK Damale, V Bekoe, CA Klufio ... To determine the Hepatitis C virus (HCV) carrier rate among mothers, and to determine if selected sociodemographic characteristics are associated with HCV seropositivity.

  3. Delivering Physical Education in selected schools in Soweto, South ...

    African Journals Online (AJOL)

    The programme utilizes Physical Education (PE) during schooltime, while building the capacity of PE teachers to teach PE and Extra School Support Programme (ESSP) coaches (a programme of the National Department of Education) to deliver school sport. The aim of the study was to evaluate the Soweto Active Schools ...

  4. VET Providers Planning to Deliver Degrees: Good Practice Guide

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2015

    2015-01-01

    This good practice guide is intended to assist public and private registered training organisations (RTOs) planning to commence higher education (HE) delivery. The guide is based on research undertaken by Victor Callan and Kaye Bowman, who completed case studies with six providers currently delivering higher education qualifications in addition to…

  5. A Review of Physical Activity Interventions Delivered via Facebook.

    Science.gov (United States)

    Ferrer, David A; Ellis, Rebecca

    2017-10-01

    The use of social networking sites to deliver behavioral interventions is becoming more prevalent. The purpose of this review was to systematically evaluate the published research to determine the effectiveness of Facebook-delivered interventions for promoting physical activity behavior change. A search of interventions delivered via Facebook (as the primary delivery method or part of a multifaceted intervention) in which physical activity was the primary or secondary outcome resulted in 8 studies for review. Overall, 87.5% of the Facebook interventions reported some type of significant physical activity behavior change (ie, interactions, main effects for time, differences between conditions); however, only 2 of these interventions found this change to be significantly better for the treatment group than the control group. Future researchers are encouraged to test the effectiveness of Facebook-delivered physical activity interventions with additional control groups that receive no aspects of the intervention within experimental study designs, more diverse samples, theory-based content with assessment of mediators of behavior change, direct observations of physical activity, and long-term follow-ups. Although based on a small sample of studies, Facebook appears to be a promising delivery method for physical activity interventions.

  6. Portable devices for delivering imagery and modelling interventions ...

    African Journals Online (AJOL)

    The main objective of this study was to investigate the effectiveness of portable devices (MP4) and a stationary device (DVD and fixed point stationary computer) in delivering imagery and modelling training among female netball players, examining the effect on imagery adherence, performance, self-efficacy, and the relative ...

  7. Inefficient charging for delivered gas by local gas distributors

    Directory of Open Access Journals (Sweden)

    Siniša Bikić

    2005-10-01

    Full Text Available In this region, especially in Serbia, common belief is that local distributors of gas used by households don’t charge for gas properly. It is suspected that there are two sources for improper ways of gas charging. Local distributors charge for delivered gas only, according to flow rat but not according to gas quality. It is usual that local distributors deliver gas of different quality than one signed in contract. In this work will be considered only one of aspects inefficient charging for delivered gas by local gas distributors, which is connected to variable atmospheric pressure. There is doubt, that local distributors make mistakes during accounting for delivered gas to costumers in regard atmospheric pressure. At the beginning of every investigation, problem has to be located and recognized. Authors are going to collect as much as possible available data, to elaborate and analyze data by scientific methods and to represent conclusions. So, the aim of this work is to diagnose current state and to approve or disapprove above mentioned suspicions. In our region this theme is very interesting, both because of energy efficiency and air pollution control. In this way both consumer and distributor will know, how mush energy they have really spent.

  8. Glucose 6 phosphate dehydrogenase levels in babies delivered at ...

    African Journals Online (AJOL)

    Background: Glucose-6-phosphate dehydrogenase deficiency, an X-linked recessive disorder, is the most common enzymopathy producing disease in humans.It is known to cause severe neonatal hyperbilirubinaemia. Aims and Objectives: To determine G6PD levels in babies delivered at the University of Ilorin Teaching ...

  9. Delivering Advanced Technical Education Using Online, Immersive Classroom Technology

    Science.gov (United States)

    Smith, Delmer; Louwagie, Nancy

    2017-01-01

    Vacuum and thin film technologies are critical to advanced manufacturing industries. With a grant from the National Science Foundation (DUE #14004080), Normandale Community College has developed courses that are delivered online and via telepresence to provide a formal education to vacuum technician students around the country. Telepresence…

  10. The Challenges of Globalisation: Delivering an MBA Programme in Eritrea.

    Science.gov (United States)

    Dence, Roger; O'Toole, John

    1999-01-01

    Describes the experiences of delivering an MBA (Master in Business Administration) program in Eritrea (North East Africa) through the United Kingdom's Open University. Discusses tutoring teams that travel to Eritrea, localizing case examples and assignments, sensitivity to local cultural contexts, writing assignments, student assessment, and…

  11. Dealing with Learner Resistance to Technology-Delivered Training.

    Science.gov (United States)

    McCormick, Patricia

    2001-01-01

    Discussion of student resistance to technology-delivered training focuses on strategies at the IRS (Internal Revenue Service) that overcame learner resistance by maintaining a personal relationship with each student and flexibly addressing each student's personal style and concerns. Considers reasons for student resistance and the continued need…

  12. The knowledge and skills gap of medical practitioners delivering ...

    African Journals Online (AJOL)

    The knowledge and skills gap of medical practitioners delivering district hospital services in the Western Cape, South Africa. ... Rural family practice requires that doctors have the knowledge and skills to practise in settings where high technology and specialist resources are not available, while at the same time requiring ...

  13. Heterologous mitochondrial targeting sequences can deliver functional proteins into mitochondria.

    Science.gov (United States)

    Marcus, Dana; Lichtenstein, Michal; Cohen, Natali; Hadad, Rita; Erlich-Hadad, Tal; Greif, Hagar; Lorberboum-Galski, Haya

    2016-12-01

    Mitochondrial Targeting Sequences (MTSs) are responsible for trafficking nuclear-encoded proteins into mitochondria. Once entering the mitochondria, the MTS is recognized and cleaved off. Some MTSs are long and undergo two-step processing, as in the case of the human frataxin (FXN) protein (80aa), implicated in Friedreich's ataxia (FA). Therefore, we chose the FXN protein to examine whether nuclear-encoded mitochondrial proteins can efficiently be targeted via a heterologous MTS (hMTS) and deliver a functional protein into mitochondria. We examined three hMTSs; that of citrate synthase (cs), lipoamide deydrogenase (LAD) and C6ORF66 (ORF), as classically MTS sequences, known to be removed by one-step processing, to deliver FXN into mitochondria, in the form of fusion proteins. We demonstrate that using hMTSs for delivering FXN results in the production of 4-5-fold larger amounts of the fusion proteins, and at 4-5-fold higher concentrations. Moreover, hMTSs delivered a functional FXN protein into the mitochondria even more efficiently than the native MTSfxn, as evidenced by the rescue of FA patients' cells from oxidative stress; demonstrating a 18%-54% increase in cell survival; and a 13%-33% increase in ATP levels, as compared to the fusion protein carrying the native MTS. One fusion protein with MTScs increased aconitase activity within patients' cells, by 400-fold. The implications form our studies are of vast importance for both basic and translational research of mitochondrial proteins as any mitochondrial protein can be delivered efficiently by an hMTS. Moreover, effective targeting of functional proteins is important for restoration of mitochondrial function and treatment of related disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Dual stimuli-responsive Fe3O4 graft poly(acrylic acid-block-poly(2-methacryloyloxyethyl ferrocenecarboxylate copolymer micromicelles: surface RAFT synthesis, self-assembly and drug release applications

    Directory of Open Access Journals (Sweden)

    Yuan Wang

    2017-10-01

    Full Text Available Abstract Background Stimuli-responsive polymer materials are a new kind of intelligent materials based on the concept of bionics, which exhibits more significant changes in physicochemical properties upon triggered by tiny environment stimuli, hence providing a good carrier platform for antitumor drug delivery. Results Dual stimuli-responsive Fe3O4 graft poly(acrylic acid-block-poly(2-methacryloyloxyethyl ferrocenecarboxylate block copolymers (Fe3O4-g-PAA-b-PMAEFC were engineered and synthesized through a two-step sequential reversible addition-fragmentation chain transfer polymerization route. The characterization was performed by FTIR, 1H NMR, SEC, XRD and TGA techniques. The self-assembly behavior in aqueous solution upon triggered by pH, magnetic and redox stimuli was investigated via zeta potentials, vibration sample magnetometer, cyclic voltammetry, fluorescent spectrometry, dynamic light scattering, XPS, TEM and SEM measurements. The experimental results indicated that the Fe3O4-g-PAA-b-PMAEFC copolymer materials could spontaneously assemble into hybrid magnetic copolymer micromicelles with core–shell structure, and exhibited superparamagnetism, redox and pH stimuli-responsive features. The hybrid copolymer micromicelles were stable and nontoxic, and could entrap hydrophobic anticancer drug, which was in turn swiftly and effectively delivered from the drug-loaded micromicelles at special microenvironments such as acidic pH and high reactive oxygen species. Conclusion This class of stimuli-responsive copolymer materials is expected to find wide applications in medical science and biology, etc., especially in drug delivery system.

  15. Replicating studies in which samples of participants respond to samples of stimuli.

    Science.gov (United States)

    Westfall, Jacob; Judd, Charles M; Kenny, David A

    2015-05-01

    In a direct replication, the typical goal is to reproduce a prior experimental result with a new but comparable sample of participants in a high-powered replication study. Often in psychology, the research to be replicated involves a sample of participants responding to a sample of stimuli. In replicating such studies, we argue that the same criteria should be used in sampling stimuli as are used in sampling participants. Namely, a new but comparable sample of stimuli should be used to ensure that the original results are not due to idiosyncrasies of the original stimulus sample, and the stimulus sample must often be enlarged to ensure high statistical power. In support of the latter point, we discuss the fact that in experiments involving samples of stimuli, statistical power typically does not approach 1 as the number of participants goes to infinity. As an example of the importance of sampling new stimuli, we discuss the bygone literature on the risky shift phenomenon, which was almost entirely based on a single stimulus sample that was later discovered to be highly unrepresentative. We discuss the use of both resampled and expanded stimulus sets, that is, stimulus samples that include the original stimuli plus new stimuli. © The Author(s) 2015.

  16. 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.

  17. Neural evidence for reduced apprehensiveness of familiarized stimuli in a mere exposure paradigm.

    Science.gov (United States)

    Zebrowitz, Leslie A; Zhang, Yi

    2012-07-01

    Mere familiarization with a stimulus increases liking for it or similar stimuli ("mere exposure" effects) as well as perceptual fluency, indexed by the speed and accuracy of categorizing it or similar stimuli ("priming" effects). Candidate mechanisms proposed to explain mere exposure effects include both increased positive affect associated with greater perceptual fluency, and reduced negative affect associated with diminished apprehensiveness of novel stimuli. Although these two mechanisms are not mutually exclusive, it is difficult for behavioral measures to disentangle them, since increased liking or other indices of greater positive affect toward exposed stimuli could result from increases in positive feelings or decreases in negative feelings or both. The present study sought to clarify this issue by building on research showing a dissociation at the neural level in which the lateral orbitofrontal cortex (LOFC) is activated more by negatively valenced than by neutral or positively valenced stimuli, with the reverse effect for medial orbitofrontal cortex (MOFC). Supporting the reduced apprehensiveness hypothesis, we found lower LOFC activation to familiarized faces and objects (repetition suppression). We did not find evidence to support the positive affect hypothesis in increased activation to familiarized stimuli in MOFC or in other parts of the reward circuit that respond more to positively valenced stimuli (repetition enhancement), although enhancement effects were shown in some regions.

  18. 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.

  19. Emotional Empathic Responses to Dynamic Negative Affective Stimuli Is Gender-Dependent

    Directory of Open Access Journals (Sweden)

    Kim P. C. Kuypers

    2017-08-01

    Full Text Available Empathy entails the ability to recognize emotional states in others and feel for them. Since empathy does not take place in a static setting, paradigms utilizing more naturalistic, dynamic stimuli instead of static stimuli are perhaps more suited to grasp the origin of this highly complex social skill. The study was set up to test the effect of stimulus dynamics and gender on empathic responses. Participants were 80 healthy volunteers (N = 40 males aged 22.5 years on average. Behavioral empathy was tested with the multifaceted empathy test, including static emotional stimuli, and the multidimensional movie empathy test (MMET, including dynamic stimuli. Findings showed emotional empathy (EE responses were higher to negative emotional stimuli in both tasks, i.e., using static as well as dynamic stimuli. Interestingly a gender-dependent response was only seen in the MMET using dynamic stimuli. It was shown that females felt more aroused and were more concerned with people in negative affective states. It was concluded that the MMET is suited to study gender differences in EE.

  20. 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. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. Multisensory Attention in Motion: Uninformative Sounds Increase the Detectability of Direction Changes of Moving Visual Stimuli

    Directory of Open Access Journals (Sweden)

    Durk Talsma

    2011-10-01

    Full Text Available It has recently been shown that spatially uninformative sounds can cause a visual stimulus to pop-out from an array of similar distractor stimuli when that sound is presented near simultaneously with a feature change in the visual stimulus. Until now, this effect has only been shown for stimuli that remain at a fixed position. Here we extend these results by showing that auditory stimuli can also improve the detectability of visual stimulus features related to motion. To accomplish this we presented moving visual stimuli (small dots on a computer screen. At a random moment during a trial, one of these stimuli could abruptly start moving in an orthogonal direction. Participants' task was to indicate whether such a change in direction had occurred or not by making a corresponding button press. When a sound (a short 1000Hz tone pip was presented simultaneously with a motion change, participants were able to detect this motion direction change among a significantly higher number of distractor stimuli, compared to when the sound was absent. When the number of distractor stimuli was kept constant, detection accuracy was significantly higher when the tone was present, compared to when it was absent. Using signal detection theory, we determined that this change in accuracy was reflected in an increase in d“, while we found no evidence to suggest that participants' response bias (as reflected nearly equal beta parameters, changed due to the presence of the sounds.

  2. Modeling Behavioral Experiment Interaction and Environmental Stimuli for a Synthetic C. elegans

    Directory of Open Access Journals (Sweden)

    Andoni Mujika

    2017-12-01

    Full Text Available This paper focusses on the simulation of the neural network of the Caenorhabditis elegans living organism, and more specifically in the modeling of the stimuli applied within behavioral experiments and the stimuli that is generated in the interaction of the C. elegans with the environment. To the best of our knowledge, all efforts regarding stimuli modeling for the C. elegansare focused on a single type of stimulus, which is usually tested with a limited subnetwork of the C. elegansneural system. In this paper, we follow a different approach where we model a wide-range of different stimuli, with more flexible neural network configurations and simulations in mind. Moreover, we focus on the stimuli sensation by different types of sensory organs or various sensory principles of the neurons. As part of this work, most common stimuli involved in behavioral assays have been modeled. It includes models for mechanical, thermal, chemical, electrical and light stimuli, and for proprioception-related self-sensed information exchange with the neural network. The developed models have been implemented and tested with the hardware-based Si elegans simulation platform.

  3. Regional differences in suprathreshold intensity for bitter and umami stimuli.

    Science.gov (United States)

    Feeney, Emma L; Hayes, John E

    2014-12-01

    The sense of taste is often referred to as a 'nutritional gatekeeper', thought to have evolved to indicate energy sources and prevent ingestion of potential toxins. Fungiform papillae are structures on the anterior tongue in which taste buds are situated. They are concentrated at the tongue's tip and they can provide a useful estimate of overall taste bud density for taste research. Some reports suggest taste perception may differ subtly across tongue regions, irrespective of FP number. Other data show an association between taste intensity perception for the bitter compound 6-n-propylthiouracil (PROP) and FP density. However, contradictions exist in the literature, with more recent, larger studies suggesting little or no association between FP number and perceived taste intensity. Much research has examined the relation between FP density and PROP perception, while other tastes have been less thoroughly studied. Here, in a cohort of mainly Caucasian individuals, aged 18-45, recruited from the campus of a large rural university, we examined regional and whole-mouth taste intensities, and FP density using an updated method of a digital still photography method first described in 2005. We found regional differences in suprathreshold intensity. Although all taste sensations were experienced all over the tongue, once again disproving the mythical tongue map, we also observed bitter and umami taste perception to be significantly greater on the posterior tongue than on the anterior tongue. In contrast, there were no regional differences observed for sweet, salty or sour tastes. The relation of FP density to whole-mouth intensity of 6- n -propylthiouracil, and to the intensity of saltiness of NaCl, sweetness from sucrose or from Acesulfame-K, bitterness of quinine, or burning from capsaicin delivered to different regions of the tongue are also discussed.

  4. Cross-modal visual and vibrotactile tracking

    NARCIS (Netherlands)

    Erp, J.B.F. van; Verschoor, M.H.

    2004-01-01

    The present study investigates tracking performance with tactile and/or visual presentation of target and cursor. The tactile display consisted of vibrators in a horizontal linear array on the torso, the visual display consisted of dots projected on a horizontal plane surrounding the observer. Both

  5. 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 /.

  6. 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

  7. 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

  8. Power Delivered to Mechanical Systems by Random Vibrations

    Directory of Open Access Journals (Sweden)

    Timothy S. Edwards

    2009-01-01

    Full Text Available This paper develops deformational response power descriptions of multiple degree-of-freedom systems due to stationary random vibration excitation. Two new concepts are developed. The deformational response power density (DRPD can be computed when a structure's natural frequencies and modal masses are available. The DRPD shows the spectral content of the deformational power delivered to a specific structure by the stationary, random excitation. This function can be found through a weighted windowing of the power spectrum of the input acceleration excitation. Deformational response input power spectra (DRIPS, similar to the input energy spectrum and shock response spectrum, give the power delivered to single-degree-of-freedom systems as a function of natural frequency. It is shown that the DRIPS is simply a smoothed version of the power spectrum of the input acceleration excitation. The DRIPS gives rise to a useful power-based data smoothing operation.

  9. Delivering phage therapy per os: benefits and barriers.

    Science.gov (United States)

    Zelasko, Susan; Gorski, Andrzej; Dabrowska, Krystyna

    2017-02-01

    Multidrug-resistant bacterial infections of the gastrointestinal tract pose a serious public health concern. High levels of antibiotic drug resistance, along with the potential for antibiotics to precipitate disease or alter the gut microbiome has prompted research into alternative treatment methods. Evidence suggests that bacteriophage therapy delivered per os may be well-suited to target such infections. Areas covered: Herein, we discuss the specific advantages and challenges of using orally administered phage therapy. Our literature review encompasses recent works using phages to target various clinically-relevant bacteria in vivo. We also provide insights into methods that aim to overcome the barriers to effective phage transit through the harsh gastrointestinal environment. Expert commentary: Evidence from a number of in vivo animal studies suggests that targeting bacterial infections using phages delivered orally holds potential. Efficacious oral phage therapy depends on the delivery of sufficient phage titers to the infection site, which may be hindered by the host's gastrointestinal tract and immune response.

  10. A small graphene oxide sheet/polyvinylidene fluoride bilayer actuator with large and rapid responses to multiple stimuli.

    Science.gov (United States)

    Xu, Guochuang; Zhang, Miao; Zhou, Qinqin; Chen, Hongwu; Gao, Tiantian; Li, Chun; Shi, Gaoquan

    2017-11-16

    A high-performance actuator should be able to deliver large-shape deformations, fast actuations and sensitive responses to multiple stimuli. Here, we report such an actuator constructed from one layer of polyvinylidene fluoride (PVDF) with a high coefficient of thermal expansion (CTE), and another layer of small sheets of graphene oxide (SGO) with a negative CTE. The opposite deformations of both actuation layers make the SGO/PVDF bilayer actuator highly sensitive to the temperature stimulus with a large bending sensitivity of 1.5 cm(-1) °C(-1). Upon irradiation with 60 mW cm(-2) infrared light, this SGO/PVDF bilayer actuator displayed an extremely rapid tip displacement rate of 140 mm s(-1). Furthermore, this actuator can also sensitively respond to moisture because of its SGO layer, showing a curvature change from -22 to 13 cm(-1) upon changing the relative humidity (RH) from 11% to 86%. This actuator can generate a contractile or relaxed stress 18 times that of mammalian skeletal muscle, under light irradiation or moisture with a response time as short as 1 s, being capable of lifting an object with a weight 80 times that of itself. Furthermore, it also showed excellent stability and repeatability.

  11. Teaching Trainees to Deliver Adolescent Reproductive Health Services.

    Science.gov (United States)

    Shah, Brandi; Chan, Serena H; Perriera, Lisa; Gold, Melanie A; Akers, Aletha Y

    2016-02-01

    Delivery of reproductive services to adolescents varies according to specialty and has been linked to differences in clinical training. Few studies have explored how different specialties' graduate medical education (GME) programs prepare providers to deliver adolescent reproductive services. We explored the perceptions of resident physicians regarding their training in delivering adolescent reproductive health services. Between November 2008 and February 2009, 9 focus groups were conducted with graduate medical trainees in 3 specialties that routinely care for adolescents. The semistructured discussions were audio-recorded, transcribed, and analyzed using an inductive approach to content analysis. Large, urban academic medical center in Pittsburgh, Pennsylvania. Fifty-four resident trainees in pediatrics, family medicine, and obstetrics/gynecology. None. Trainees' perspectives regarding the didactic teaching and clinical training in providing adolescent reproductive services. Five themes emerged, reflecting trainees' beliefs regarding the best practices in which GME programs can engage to ensure that trainees graduate with the belief that they are competent and will be comfortable delivering adolescent reproductive services. Trainees believed programs need to: (1) provide didactic lectures and diverse inpatient and outpatient clinical experiences; (2) have faculty preceptors skilled in providing and supervising adolescent reproductive services; (3) teach skills for engaging adolescents in clinical assessments and decision-making; (4) train providers to navigate confidentiality issues with adolescents and caregivers; and (5) provide infrastructure and resources for delivering adolescent reproductive services. The 3 specialties differed in how well each of the 5 best practices were reportedly addressed during GME training. Policy recommendations are provided. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc

  12. Examining the cost of delivering routine immunization in Honduras.

    Science.gov (United States)

    Janusz, Cara Bess; Castañeda-Orjuela, Carlos; Molina Aguilera, Ida Berenice; Felix Garcia, Ana Gabriela; Mendoza, Lourdes; Díaz, Iris Yolanda; Resch, Stephen C

    2015-05-07

    Many countries have introduced new vaccines and expanded their immunization programs to protect additional risk groups, thus raising the cost of routine immunization delivery. Honduras recently adopted two new vaccines, and the country continues to broaden the reach of its program to adolescents and adults. In this article, we estimate and examine the economic cost of the Honduran routine immunization program for the year 2011. The data were gathered from a probability sample of 71 health facilities delivering routine immunization, as well as 8 regional and 1 central office of the national immunization program. Data were collected on vaccinations delivered, staff time dedicated to the program, cold chain equipment and upkeep, vehicle use, infrastructure, and other recurrent and capital costs at each health facility and administrative office. Annualized economic costs were estimated from a modified societal perspective and reported in 2011 US dollars. With the addition of rotavirus and pneumococcal conjugate vaccines, the total cost for routine immunization delivery in Honduras for 2011 was US$ 32.5 million. Vaccines and related supplies accounted for 23% of the costs. Labor, cold chain, and vehicles represented 54%, 4%, and 1%, respectively. At the facility level, the non-vaccine system costs per dose ranged widely, from US$ 25.55 in facilities delivering fewer than 500 doses per year to US$ 2.84 in facilities with volume exceeding 10,000 doses per year. Cost per dose was higher in rural facilities despite somewhat lower wage rates for health workers in these settings; this appears to be driven by lower demand for services per health worker in sparsely populated areas, rather than increased cost of outreach. These more-precise estimates of the operational costs to deliver routine immunizations provide program managers with important information for mobilizing resources to help sustain the program and for improving annual planning and budgeting as well as longer

  13. THE SELLER'S OBLIGATION TO DELIVER THE GOODS ACCORDING TO CISG

    OpenAIRE

    Dan VELICU

    2017-01-01

    This article aims to analyze the seller's obligations under the Convention on International Sale of Goods (CISG) and in particular the obligation to deliver the goods showing the main issues that arise in an international sale. We also wish to point the major innovations or improvements brought by the CISG in comparison to the European civil codes regulation and to conclude if the CSIG managed to revolutionize the tradition view on this issue.

  14. Viability and Functionality of Cells Delivered from Peptide Conjugated Scaffolds

    OpenAIRE

    Vacharathit, Voranaddha; Silva, Eduardo A.; Mooney, David J.

    2011-01-01

    Many cell-based therapies aim to transplant functional cells to revascularize damaged tissues and ischemic areas. However, conventional cell therapy is not optimally efficient: massive cell death, damage, and non-localization of cells both spatially and temporally all likely contribute to poor tissue functionality. An alginate cell depot system has been proposed as an alternative means to deliver outgrowth endothelial cells (OECs) in a spatiotemporally controllable manner while protecting the...

  15. THE SELLER'S OBLIGATION TO DELIVER THE GOODS ACCORDING TO CISG

    Directory of Open Access Journals (Sweden)

    Dan VELICU

    2017-05-01

    Full Text Available This article aims to analyze the seller's obligations under the Convention on International Sale of Goods (CISG and in particular the obligation to deliver the goods showing the main issues that arise in an international sale. We also wish to point the major innovations or improvements brought by the CISG in comparison to the European civil codes regulation and to conclude if the CSIG managed to revolutionize the tradition view on this issue.

  16. Delivering Sustainability Through Supply Chain Distribution Network Redesign

    OpenAIRE

    Denise Ravet

    2013-01-01

    Purpose - Companies could gain (cost, service, green/sustainable) competitive advantage through the supply chain network. The goal of this article is to study how to deliver sustainability through the supply chain distribution network redesign.Design/methodology/approach - A literature review is conducted to examine research relating to sustainable supply chain strategies and supply chain distribution network redesign.Findings - A study of the supply chain literature reveals the importance to...

  17. Delivering business analytics practical guidelines for best practice

    CERN Document Server

    Stubbs, Evan

    2013-01-01

    AVOID THE MISTAKES THAT OTHERS MAKE - LEARN WHAT LEADS TO BEST PRACTICE AND KICKSTART SUCCESS This groundbreaking resource provides comprehensive coverage across all aspects of business analytics, presenting proven management guidelines to drive sustainable differentiation. Through a rich set of case studies, author Evan Stubbs reviews solutions and examples to over twenty common problems spanning managing analytics assets and information, leveraging technology, nurturing skills, and defining processes. Delivering Business Analytics also outlines the Data Scientist's Code, fifteen principle

  18. HyVE: hybrid vibro-electrotactile stimulation for sensory feedback and substitution in rehabilitation.

    Science.gov (United States)

    D'Alonzo, Marco; Dosen, Strahinja; Cipriani, Christian; Farina, Dario

    2014-03-01

    Electro- or vibro-tactile stimulations were used in the past to provide sensory information in many different applications ranging from human manual control to prosthetics. The two modalities were used separately in the past, and we hypothesized that a hybrid vibro-electrotactile (HyVE) stimulation could provide two afferent streams that are independently perceived by a subject, although delivered in parallel and through the same skin location. We conducted psychophysical experiments where healthy subjects were asked to recognize the intensities of electroand vibro-tactile stimuli during hybrid and single modality stimulations. The results demonstrated that the subjects were able to discriminate the features of the two modalities within the hybrid stimulus, and that the cross-modality interaction was limited enough to allow better transmission of discrete information (messages) using hybrid versus singlemodality coding. The percentages of successful recognitions (mean ± standard deviation) for nine messages were 56 ± 11 % and 72 ± 8 % for two hybrid coding schemes, compared to 29 ±7 % for vibrotactile and 44 ± 4 % for electrotactile coding. The HyVE can be therefore an attractivesolution in numerous application for providing sensory feedbackin prostheses and rehabilitation, and it could be used to increase the resolution of a single variable or to simultaneously feedback two different variables.

  19. Wavefront aberration changes caused by a gradient of increasing accommodation stimuli

    National Research Council Canada - National Science Library

    Zhou, X-Y; Wang, L; Zhou, X-T; Yu, Z-Q

    2015-01-01

    ...), were included in this study. After dilating the right pupil with 0.5% phenylephrine drops, the wavefront aberration of the right eye was measured continuously either without or with 1, 2, 3, 4, 5, or 6D accommodation stimuli...

  20. Continuous fabrication of multi-stimuli responsive graphene oxide composite hydrogel fibres by microfluidics

    NARCIS (Netherlands)

    Peng, Li; Liu, Yan; Gong, Jinghua; Zhang, Kaihuan; Ma, Jinghong

    2017-01-01

    Microfluidics appeared in the 1990s as a promising technology and has received considerable attention in developing stimuli-responsive hydrogel fibres in microscale for tissue engineering and actuation devices. In this work, thermo- and electro-responsive graphene

  1. Resting frontal EEG alpha-asymmetry predicts the evaluation of affective musical stimuli.

    Science.gov (United States)

    Schmidt, Barbara; Hanslmayr, Simon

    2009-09-04

    Resting frontal electroencephalographic (EEG) alpha-asymmetry was measured in 16 participants to predict affective responses to musical stimuli. Three affective musical stimuli either expressing neutral, positive or negative mood were evaluated by the subjects concerning "expressed mood" and "level of enjoyment". The results show that individuals with relatively higher alpha power over right frontal electrode sites rated all stimuli more positive than participants with relatively higher alpha power over left frontal electrode sites. On the "expressed mood" scale, the valence of the stimuli did not influence the difference between the ratings of left- and right-active individuals. On the "enjoyment" scale, the largest difference between the ratings of left- and right-active individuals emerged in the negative condition. The results are specific to the alpha frequency band. In line with previous studies, these results suggest that resting frontal alpha-asymmetry reflects a person's predisposition to respond affectively.

  2. Changes in Plasma Copeptin Levels during Hemodialysis : Are the Physiological Stimuli Active in Hemodialysis Patients?

    NARCIS (Netherlands)

    Ettema, Esmee M.; Kuipers, Johanna; Assa, Solmaz; Bakker, Stephan J. L.; Groen, Henk; Westerhuis, Ralf; Gaillard, Carlo A. J. M.; Gansevoort, Ron T.; Franssen, Casper F. M.

    2015-01-01

    Objectives Plasma levels of copeptin, a surrogate marker for the vasoconstrictor hormone arginine vasopressin (AVP), are increased in hemodialysis patients. Presently, it is unknown what drives copeptin levels in hemodialysis patients. We investigated whether the established physiological stimuli

  3. The Effect of Pre-Adapting Spectral Stimuli on Visual Response.

    Science.gov (United States)

    of the response parameters than stimuli from the short wavelength end of the spectrum. The implications of the findings for display design and cockpit-light-source design and management are discussed. (Author)

  4. A new bioreactor for the controlled application of complex mechanical stimuli for cartilage tissue engineering.

    Science.gov (United States)

    Laganà, K; Moretti, M; Dubini, G; Raimondi, M T

    2008-07-01

    Mechanical stimuli have been shown to enhance chondrogenesis on both animal and human chondrocytes cultured in vitro. Different mechanical stimuli act simultaneously in vivo in cartilage tissue and their effects have been extensively studied in vitro, although often in a separated manner. A new bioreactor is described where different mechanical stimuli, i.e. shear stress and hydrostatic pressure, can be combined in different ways to study the mechanobiology of tissue engineered cartilage. Shear stress is imposed on cells by forcing the culture medium through the scaffolds, whereas a high hydrostatic pressure up to 15 MPa is generated by pressurizing the culture medium. Fluid-dynamic experimental tests have been performed and successful validation of the bioreactor has been carried out by dynamic culture of tissue-engineered cartilage constructs. The bioreactor system allows the investigation of the combined effects of different mechanical stimuli on the development of engineered cartilage, as well as other possible three-dimensional tissue-engineered constructs.

  5. 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.

  6. Suppressed visual looming stimuli are not integrated with auditory looming signals: Evidence from continuous flash suppression.

    Science.gov (United States)

    Moors, Pieter; Huygelier, Hanne; Wagemans, Johan; de-Wit, Lee; van Ee, Raymond

    2015-01-01

    Previous studies using binocular rivalry have shown that signals in a modality other than the visual can bias dominance durations depending on their congruency with the rivaling stimuli. More recently, studies using continuous flash suppression (CFS) have reported that multisensory integration influences how long visual stimuli remain suppressed. In this study, using CFS, we examined whether the contrast thresholds for detecting visual looming stimuli are influenced by a congruent auditory stimulus. In Experiment 1, we show that a looming visual stimulus can result in lower detection thresholds compared to a static concentric grating, but that auditory tone pips congruent with the looming stimulus did not lower suppression thresholds any further. In Experiments 2, 3, and 4, we again observed no advantage for congruent multisensory stimuli. These results add to our understanding of the conditions under which multisensory integration is possible, and suggest that certain forms of multisensory integration are not evident when the visual stimulus is suppressed from awareness using CFS.

  7. Effects of stimuli organization on identity matching-to-sample performances of persons with autism

    National Research Council Canada - National Science Library

    Camila Graciella Santos Gomes; Deisy das Graças de Souza

    2008-01-01

      This study assessed the performance of 20 persons with autism in an identity matching-to-sample task, using two procedures with different stimuli arrangements and different response requirements...

  8. Impaired Attentional Disengagement from Stimuli Matching the Contents of Working Memory in Social Anxiety

    Science.gov (United States)

    Moriya, Jun; Sugiura, Yoshinori

    2012-01-01

    Although many cognitive models in anxiety propose that an impaired top-down control enhances the processing of task-irrelevant stimuli, few studies have paid attention to task-irrelevant stimuli under a cognitive load task. In the present study, we investigated the effects of the working memory load on attention to task-irrelevant stimuli in trait social anxiety. The results showed that as trait social anxiety increased, participants were unable to disengage from task-irrelevant stimuli identical to the memory cue under low and high working memory loads. Impaired attentional disengagement was positively correlated with trait social anxiety. This impaired attentional disengagement was related to trait social anxiety, but not state anxiety. Our findings suggest that socially anxious people have difficulty in disengaging attention from a task-irrelevant memory cue owing to an impaired top-down control under a working memory load. PMID:23071765

  9. Impaired attentional disengagement from stimuli matching the contents of working memory in social anxiety.

    Directory of Open Access Journals (Sweden)

    Jun Moriya

    Full Text Available Although many cognitive models in anxiety propose that an impaired top-down control enhances the processing of task-irrelevant stimuli, few studies have paid attention to task-irrelevant stimuli under a cognitive load task. In the present study, we investigated the effects of the working memory load on attention to task-irrelevant stimuli in trait social anxiety. The results showed that as trait social anxiety increased, participants were unable to disengage from task-irrelevant stimuli identical to the memory cue under low and high working memory loads. Impaired attentional disengagement was positively correlated with trait social anxiety. This impaired attentional disengagement was related to trait social anxiety, but not state anxiety. Our findings suggest that socially anxious people have difficulty in disengaging attention from a task-irrelevant memory cue owing to an impaired top-down control under a working memory load.

  10. Increased reward value of nonsocial stimuli in children and adolescents with autism

    Directory of Open Access Journals (Sweden)

    Karli K Watson

    2015-07-01

    Full Text Available We used an econometric choice task to estimate the implicit reward value of social and nonsocial stimuli related to restricted interests in children and adolescents with (n=12 and without (n=22 ASD. Mixed effects logistic regression analyses revealed that children and adolescents with ASD were willing to receive less cash payout to view restricted interest stimuli, whereas children and adolescents without ASD were indifferent to cash payouts to view these images. Groups did not differ in valuation of social images or nonsocial images unrelated to restricted interests. Our findings reveal that individuals with ASD assign enhanced reward value of nonsocial stimuli related to restricted interests in ASD. These results suggest that motivational accounts of ASD should also consider the reward value of restricted interests in addition to that of social stimuli (Dichter & Adolphs, 2012.

  11. Categorization of Extremely Brief Auditory Stimuli: Domain-Specific or Domain-General Processes?

    Science.gov (United States)

    Bigand, Emmanuel; Delbé, Charles; Gérard, Yannick; Tillmann, Barbara

    2011-01-01

    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. PMID:22046436

  12. 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

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

    Science.gov (United States)

    Kim, Young-Suk Grace

    2016-01-01

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

  14. Heavy cannabis use and attentional avoidance of anxiety-related stimuli

    OpenAIRE

    Wilcockson, T.D.W.; Sanal, N.E.M.

    2016-01-01

    Objectives: Cannabis is now the most widely used illicit substance in the world. Previous research demonstrates that cannabis use is associated with dysfunctional affect regulation and anxiety. Anxiety is characterised by attentional biases in the presence of emotional information. This novel study therefore examined the attentional bias of cannabis users when presented with anxiety-related stimuli. The aim was to establish whether cannabis users respond to anxiety-related stimuli differently...

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

    OpenAIRE

    Jamie eWard; Peter eHovard; Alicia eJones; Nicolas eRothen

    2013-01-01

    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, par...

  17. Quadruple Stimuli-Responsive Mechanized Silica Nanoparticles: A Promising Multifunctional Nanomaterial for Diverse Applications.

    Science.gov (United States)

    Ding, ChenDi; Tong, Ling; Fu, JiaJun

    2017-10-26

    Novel quadruple stimuli-responsive mechanized silica nanoparticles were constructed by installation of supramolecular nanovalves onto the exterior surface of mesoporous silica nanoparticles. The release of cargo molecules is triggered by acid/Zn2+ /alkali/reduction potential stimuli. This has potential application in the development of drug delivery systems or construction of smart anticorrosion coatings. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Exposure to in vivo stimuli and attentional bias among female smokers.

    Science.gov (United States)

    Correa, John B; Brandon, Thomas H

    2016-10-01

    Cross-sectional and experimental research has shown that female smokers use cigarettes to manage dietary restraint and body image dissatisfaction. The goal of this study was to investigate the cross-motivational impact of food and cigarettes by comparing attentional bias to smoking images against other images (food and jewelry) and testing how in vivo stimuli (cigarettes, food, and jewelry) affect attentional bias to these images. Thirty-five female smokers completed 3 image-viewing tasks during which they viewed images containing smoking, food, and jewelry pictorial stimuli. During these tasks, participants held smoking, food, or jewelry in vivo stimuli, and eye-tracking technology collected gaze data. We hypothesized that in vivo appetitive stimuli would produce attentional bias, with in vivo smoking stimuli increasing attention to smoking images and in vivo food stimuli increasing attention to smoking and food images. However, in vivo cigarettes and snack foods did not prime attentional biases to pictorial smoking or food stimuli. Yet, initial and maintained attention to smoking images were greater than attention to food and jewelry images when participants were administered an active comparison in vivo stimulus (jewelry). The results in this in vivo condition replicate previous research demonstrating attentional biases for smoking images among smokers, and they extend it by including the appetitive food comparison condition. These results also show that attention allocation changes when smokers encounter appetitive in vivo stimuli. Thus, this study demonstrates that establishing external validity in attentional bias research is challenging, and it encourages further psychometric exploration of such methodologies through other procedural manipulations. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Relapse to drug seeking following prolonged abstinence: the role of environmental stimuli

    OpenAIRE

    Fuchs, R.A.; Lasseter, H.C.; Ramirez, D.R.; Xie, X

    2008-01-01

    Successful treatment of drug addiction must involve relapse prevention informed by our understanding of the neurobiological bases of drug relapse. In humans, exposure to drug-associated environmental stimuli can elicit drug craving and relapse. Because exposure to drug-paired stimuli similarly induces drug-seeking behavior in laboratory animals, several animal models of drug relapse have been developed. Here, we review animal models of cue-induced drug relapse and critically evaluate their va...

  20. Statistical modeling of the response characteristics of mechanosensitive stimuli in the human esophagus

    DEFF Research Database (Denmark)

    Drewes, Asbjørn Mohr; Reddy, Hari Prasad; Ståhl, Camilla

    2005-01-01

    by using a statistical model based on correlation analysis. The esophagus was distended with a bag in 32 healthy subjects by using an inflation rate of 25 mL/min. The luminal cross-sectional areas and sensory ratings were determined during the distentions. The stimuli were repeated after relaxation...... of mechanical gut stimuli in human beings. This might increase our understanding of visceral pain in health and disease and guide the statistical analysis of experimental data obtained in the gastrointestinal tract....

  1. Lost in space--the fate of memory representations for non-neglected stimuli.

    Science.gov (United States)

    Ferber, Susanne; Danckert, James

    2006-01-01

    Typically, spatial neglect after right-hemisphere brain damage is defined as a failure to orient towards or attend to stimuli located towards the contralesional, in this case the left, side of space. Here, we report that neglect patients have difficulty maintaining the spatial locations of vertically arranged stimuli on the right side of space. This indicates that neglect is associated with a severe deficit in the maintenance of spatial information even on the ipsilesional "good" side.

  2. Self-delivered misinformation - Merging the choice blindness and misinformation effect paradigms

    Science.gov (United States)

    Stille, Lotta; Norin, Emelie; Sikström, Sverker

    2017-01-01

    Choice blindness is the failure to detect a discrepancy between a choice and its outcome. The misinformation effect occurs when the recollection of an event changes because new, misleading information about the event is received. The purpose of this study was to merge the choice blindness and misinformation effect paradigms, and thus examine whether choice blindness can be created for individuals’ recollections of a witnessed event, and whether this will affect their later recollections of the event. Thus, as a way of delivering misinformation the participants ostensibly became their own source of the misleading information. The participants watched a short film and filled out a questionnaire about events shown in the film. Some of their answers were then manipulated using reattachable stickers, which allowed alteration of their original answers. The participants gave justifications for their manipulated choices, and later their recollection of the original event was tested through another questionnaire. Choice blindness was created for a majority of the participants. A majority of the choice blind participants later changed their reported recollection of the event in line with the manipulations, whereas only a small minority of the participants in the control condition changed their recollection. This study provides new information about the misinformation effect, suggesting that this effect also can occur when misinformation is given immediately following presentation of the original stimuli, and about choice blindness and its effects on the recollections of events. The results suggest that memory blindness can be created when people inadvertently supply themselves with misleading information about an event, causing a change in their recollection. PMID:28273151

  3. Stimuli-responsive copolymer solution and surface assemblies for biomedical applications

    Science.gov (United States)

    Kelley, Elizabeth G.; Albert, Julie N. L.

    2013-01-01

    Stimuli-responsive polymeric materials is one of the fastest growing fields of the 21st century, with the annual number of papers published more than quadrupling in the last ten years. The responsiveness of polymer solution assemblies and surfaces to biological stimuli (e.g. pH, reduction-oxidation, enzymes, glucose) and externally applied triggers (e.g. temperature, light, solvent quality) shows particular promise for various biomedical applications including drug delivery, tissue engineering, medical diagnostics, and bioseparations. Furthermore, the integration of copolymer architectures into stimuli-responsive materials design enables exquisite control over the locations of responsive sites within self-assembled nanostructures. The combination of new synthesis techniques and well-defined copolymer self-assembly has facilitated substantial developments in stimuli-responsive materials in recent years. In this tutorial review, we discuss several methods that have been employed to synthesize self-assembling and stimuli-responsive copolymers for biomedical applications, and we identify common themes in the response mechanisms among the targeted stimuli. Additionally, we highlight parallels between the chemistries used for generating solution assemblies and those employed for creating copolymer surfaces. PMID:23403471

  4. 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.

  5. Alpha oscillations in response to affective and cigarette-related stimuli in smokers.

    Science.gov (United States)

    Cui, Yong; Versace, Francesco; Engelmann, Jeffrey M; Minnix, Jennifer A; Robinson, Jason D; Lam, Cho Y; Karam-Hage, Maher; Brown, Victoria L; Wetter, David W; Dani, John A; Kosten, Thomas R; Cinciripini, Paul M

    2013-05-01

    The presence of cigarette-related cues has been associated with smoking relapse. These cues are believed to activate brain mechanisms underlying emotion, attention, and memory. Electroencephalography (EEG) alpha desynchronization (i.e., reduction in alpha power) has been suggested to index the engagement of these mechanisms. Analyzing EEG alpha desynchronization in response to affective and smoking cues might improve our understanding of how smokers process these cues, and the potential impact of this processing on relapse. Before the start of a medication-assisted cessation attempt, we recorded EEG from 179 smokers during the presentation of neutral, pleasant, unpleasant, and cigarette-related pictures. Wavelet analysis was used to extract EEG alpha oscillations (8-12 Hz) in response to these pictures. Alpha oscillations were analyzed as a function of picture valence and arousal dimensions. Emotional and cigarette-related stimuli induced a higher level of alpha desynchronization (i.e., less power in the alpha frequency band) than neutral stimuli. In addition, the level of alpha desynchronization induced by cigarette-related stimuli was similar to that induced by highly arousing stimuli (i.e., erotica and mutilations). These results suggest that, for smokers, cigarette-related cues are motivationally significant stimuli that may engage emotional, attentional, and memory-related neural mechanisms at a level comparable to that seen in response to highly arousing stimuli. This finding suggests that activation of emotional, attentional, and memory-related brain mechanisms may be an important contributor to cue-induced smoking relapse.

  6. Global motion processing in human color vision: a deficit for second-order stimuli.

    Science.gov (United States)

    Garcia-Suarez, Luis; Mullen, Kathy T

    2010-12-16

    The investigation of the mechanism of global motion in color vision has been limited because the processing of the first-order chromatic RDK elements, based on low-level linear motion detectors, is impaired. Here we return to this problem by using second-order elements in a global motion stimulus. Second-order RDK elements were circular contrast-modulated (CM) envelopes of a low-pass filtered noise carrier. The stimuli were achromatic or isolated L/M- or S-cone opponent mechanisms. We measured simultaneously detection and motion direction identification thresholds at 100% motion coherence and at different RDK speeds with a 2-AFC paradigm. We found that direction identification thresholds were higher than detection thresholds for both chromatic and achromatic stimuli. The gap between these thresholds was greater for the chromatic than the achromatic stimuli and motion direction thresholds for the chromatic RDK were very high or impossible to obtain. We also measured global motion performance (RDK speed of 4 deg/s) by varying the coherence of limited lifetime RDK stimuli. Global motion thresholds could only be obtained for achromatic stimuli and not for chromatic ones. Within the limits of the present stimulus conditions, we found no global motion processing of second-order chromatic stimuli.

  7. 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.

  8. Neurons in Primate Visual Cortex Alternate between Responses to Multiple Stimuli in Their Receptive Field

    Science.gov (United States)

    Li, Kang; Kozyrev, Vladislav; Kyllingsbæk, Søren; Treue, Stefan; Ditlevsen, Susanne; Bundesen, Claus

    2016-01-01

    A fundamental question concerning representation of the visual world in our brain is how a cortical cell responds when presented with more than a single stimulus. We find supportive evidence that most cells presented with a pair of stimuli respond predominantly to one stimulus at a time, rather than a weighted average response. Traditionally, the firing rate is assumed to be a weighted average of the firing rates to the individual stimuli (response-averaging model) (Bundesen et al., 2005). Here, we also evaluate a probability-mixing model (Bundesen et al., 2005), where neurons temporally multiplex the responses to the individual stimuli. This provides a mechanism by which the representational identity of multiple stimuli in complex visual scenes can be maintained despite the large receptive fields in higher extrastriate visual cortex in primates. We compare the two models through analysis of data from single cells in the middle temporal visual area (MT) of rhesus monkeys when presented with two separate stimuli inside their receptive field with attention directed to one of the two stimuli or outside the receptive field. The spike trains were modeled by stochastic point processes, including memory effects of past spikes and attentional effects, and statistical model selection between the two models was performed by information theoretic measures as well as the predictive accuracy of the models. As an auxiliary measure, we also tested for uni- or multimodality in interspike interval distributions, and performed a correlation analysis of simultaneously recorded pairs of neurons, to evaluate population behavior. PMID:28082892

  9. Anxiety and autonomic response to social-affective stimuli in individuals with Williams syndrome.

    Science.gov (United States)

    Ng, Rowena; Bellugi, Ursula; Järvinen, Anna

    2016-12-01

    Williams syndrome (WS) is a genetic condition characterized by an unusual "hypersocial" personality juxtaposed by high anxiety. Recent evidence suggests that autonomic reactivity to affective face stimuli is disorganised in WS, which may contribute to emotion dysregulation and/or social disinhibition. Electrodermal activity (EDA) and mean interbeat interval (IBI) of 25 participants with WS (19 - 57 years old) and 16 typically developing (TD; 17-43 years old) adults were measured during a passive presentation of affective face and voice stimuli. The Beck Anxiety Inventory was administered to examine associations between autonomic reactivity to social-affective stimuli and anxiety symptomatology. The WS group was characterized by higher overall anxiety symptomatology, and poorer anger recognition in social visual and aural stimuli relative to the TD group. No between-group differences emerged in autonomic response patterns. Notably, for participants with WS, increased anxiety was uniquely associated with diminished arousal to angry faces and voices. In contrast, for the TD group, no associations emerged between anxiety and physiological responsivity to social-emotional stimuli. The anxiety associated with WS appears to be intimately related to reduced autonomic arousal to angry social stimuli, which may also be linked to the characteristic social disinhibition. Copyright © 2016. Published by Elsevier Ltd.

  10. Perceptual learning with complex visual stimuli is based on location, rather than content, of discriminating features.

    Science.gov (United States)

    Jones, Scott P; Dwyer, Dominic M

    2013-04-01

    Exposure to complex checkerboards (comprising a common background, e.g., X, with unique features, e.g., A-D, that are placed in particular locations on the background) improves discrimination between them (perceptual learning). Such stimuli have been used previously to probe human perceptual learning but these studies leave open the question of whether the improvement in discrimination is based on the content or location of the unique stimuli. Experiment 1 suggests that perceptual learning produced by exposure to AX and BX transferred to stimuli that had new unique features (e.g., C, D) in the position that had been occupied by A and B during exposure. However, there was no transfer to stimuli that retained A and B as the unique features but moved them to a different location on the background. Experiment 2 replicated the key features of Experiment 1, that is, no transfer of exposure learning based on content but perfect transfer of exposure learning based on location using a design which allowed for independent tests of location- and content-based performance. In both the experiments reported here, superior discrimination between similar stimuli on the basis of exposure can be explained entirely by learning where to look, with no independent effect of learning about particular stimulus features. These results directly challenge the interpretation of practically all prior experiments using the same type of design and stimuli.

  11. The effect of semantic congruence for visual-auditory bimodal stimuli.

    Science.gov (United States)

    Xingwei An; Yong Cao; Jinwen Wei; Shuang Liu; Xuejun Jiao; Dong Ming

    2017-07-01

    It is commonly believed that brain has faster reaction speed and higher reaction accuracy on visual-auditory bimodal stimuli than single modal stimuli in current neuropsychological researches, while visual-auditory bimodal stimuli (VABS) do not show corresponding superiority in BCI system. This paper aims at investigating whether semantically congruent stimuli could also get better performance than semantically incongruent stimuli in Brain Computer Interface (BCI) system. Two VABS based paradigms (semantically congruent or incongruent) were conducted in this study. 10 healthy subjects participated in the experiment in order to compare the two paradigms. The results indicated that the higher Event-related potential (ERP) amplitude of semantic incongruent paradigm were observed both in target and non-target stimuli. Nevertheless, we didn't observe significant difference of classification accuracy between congruent and incongruent conditions. Most participants showed their preference on semantically congruent condition for less workload needed. This finding demonstrated that semantic congruency has positive effect on behavioral results (less workload) and insignificant effect on system efficiency.

  12. 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.

  13. 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.

  14. How optimal stimuli for sensory neurons are constrained by network architecture.

    Science.gov (United States)

    DiMattina, Christopher; Zhang, Kechen

    2008-03-01

    Identifying the optimal stimuli for a sensory neuron is often a difficult process involving trial and error. By analyzing the relationship between stimuli and responses in feedforward and stable recurrent neural network models, we find that the stimulus yielding the maximum firing rate response always lies on the topological boundary of the collection of all allowable stimuli, provided that individual neurons have increasing input-output relations or gain functions and that the synaptic connections are convergent between layers with nondegenerate weight matrices. This result suggests that in neurophysiological experiments under these conditions, only stimuli on the boundary need to be tested in order to maximize the response, thereby potentially reducing the number of trials needed for finding the most effective stimuli. Even when the gain functions allow firing rate cutoff or saturation, a peak still cannot exist in the stimulus-response relation in the sense that moving away from the optimum stimulus always reduces the response. We further demonstrate that the condition for nondegenerate synaptic connections also implies that proper stimuli can independently perturb the activities of all neurons in the same layer. One example of this type of manipulation is changing the activity of a single neuron in a given processing layer while keeping that of all others constant. Such stimulus perturbations might help experimentally isolate the interactions of selected neurons within a network.

  15. Usage of drip drops as stimuli in an auditory P300 BCI paradigm.

    Science.gov (United States)

    Huang, Minqiang; Jin, Jing; Zhang, Yu; Hu, Dewen; Wang, Xingyu

    2018-02-01

    Recently, many auditory BCIs are using beeps as auditory stimuli, while beeps sound unnatural and unpleasant for some people. It is proved that natural sounds make people feel comfortable, decrease fatigue, and improve the performance of auditory BCI systems. Drip drop is a kind of natural sounds that makes humans feel relaxed and comfortable. In this work, three kinds of drip drops were used as stimuli in an auditory-based BCI system to improve the user-friendness of the system. This study explored whether drip drops could be used as stimuli in the auditory BCI system. The auditory BCI paradigm with drip-drop stimuli, which was called the drip-drop paradigm (DP), was compared with the auditory paradigm with beep stimuli, also known as the beep paradigm (BP), in items of event-related potential amplitudes, online accuracies and scores on the likability and difficulty to demonstrate the advantages of DP. DP obtained significantly higher online accuracy and information transfer rate than the BP ( p  < 0.05, Wilcoxon signed test; p  < 0.05, Wilcoxon signed test). Besides, DP obtained higher scores on the likability with no significant difference on the difficulty ( p  < 0.05, Wilcoxon signed test). The results showed that the drip drops were reliable acoustic materials as stimuli in an auditory BCI system.

  16. The Effects of Mechanical and Thermal Stimuli on Local Field Potentials and Single Unit Activity in Parkinson's Disease Patients.

    Science.gov (United States)

    Belasen, Abigail; Youn, Youngwon; Gee, Lucy; Prusik, Julia; Lai, Brant; Ramirez-Zamora, Adolfo; Rizvi, Khizer; Yeung, Philip; Shin, Damian S; Argoff, Charles; Pilitsis, Julie G

    2016-10-01

    Chronic pain is a major, debilitating symptom of Parkinson's disease (PD). Although, deep brain stimulation (DBS) has been shown to improve pain outcomes, the mechanisms underlying this phenomenon are unclear. Microelectrode recording allows us to measure both local field potentials (LFPs) and single neuronal unit activity (SUA). In this study, we examined how single unit and LFP oscillatory activity in the basal ganglia are impacted by mechanical and thermal sensory stimuli and explored their role in pain modulation. We assessed changes in LFPs and SUAs in the subthalamic nucleus (STN), globus pallidus interna (Gpi), and globus pallidus externa (Gpe) following exposure with mechanical or thermal stimuli. Sensory thresholds were determined pre-operatively using quantitative sensory testing. Based on these data, patients were exposed to innocuous and noxious mechanical, pressure, and thermal stimuli at individualized thresholds. In the STN, LFP alpha oscillatory activity and SUA increased in response to innocuous mechanical stimuli; SUA further increased in response to noxious mechanical, noxious pressure, and noxious thermal stimuli (p < 0.05). In the Gpe, LFP low betaactivity and SUA increased with noxious thermal stimuli; SUA also increased in response to innocuous thermal stimuli (p < 0.05). In the Gpi, innocuous thermal stimuli increased LFP gammaactivity; noxious pressure stimuli decreased low betaactivity; SUA increased in response to noxious thermal stimuli (p < 0.05). Our study is the first to demonstrate that mechanical and thermal stimuli alter basal ganglia LFPs and SUAs in PD. While STN SUA increases nearly uniformly to all sensory stimuli, SUA in the pallidal nuclei respond solely to thermal stimuli. Similarly, thermal stimuli yield increases in pallidal LFP activity, but not STN activity. We speculate that DBS may provide analgesia through suppression of stimuli-specific changes in basal ganglia activity, supporting a role for these nuclei

  17. Variability in delivered dose and respirable delivered dose from nebulizers: are current regulatory testing guidelines sufficient to produce meaningful information?

    Directory of Open Access Journals (Sweden)

    Hatley RHM

    2017-02-01

    Full Text Available Ross HM Hatley, Sarah M Byrne Respironics Respiratory Drug Delivery (UK Ltd, a business of Philips Electronics UK Limited, Chichester, UK Background: To improve convenience to patients, there have been advances in the operation of nebulizers, resulting in fast treatment times and less drug lost to the environment. However, limited attention has been paid to the effects of these developments on the delivered dose (DD and respirable delivered dose (RDD. Published pharmacopoeia and ISO testing guidelines for adult-use testing utilize a single breathing pattern, which may not be sufficient to enable effective comparisons between the devices.Materials and methods: The DD of 5 mg of salbutamol sulfate into adult breathing patterns with inhalation:exhalation (I:E ratios between 1:1 and 1:4 was determined. Droplet size was determined by laser diffraction and RDD calculated. Nine different nebulizer brands with different modes of operation (conventional, venturi, breath-enhanced, mesh, and breath-activated were tested.Results: Between the non-breath-activated nebulizers, a 2.5-fold difference in DD (~750–1,900 µg salbutamol was found; with RDD, there was a more than fourfold difference (~210–980 µg. With increasing time spent on exhalation, there were progressive reductions in DD and RDD, with the RDD at an I:E ratio of 1:4 being as little as 40% of the dose with the 1:1 I:E ratio. The DD and RDD from the breath-activated mesh nebulizer were independent of the I:E ratio, and for the breath-activated jet nebulizer, there was less than 20% change in RDD between the I:E ratios of 1:1 and 1:4.Conclusion: Comparing nebulizers using the I:E ratio recommended in the guidelines does not predict relative performance between the devices at other ratios. There was significant variance in DD or RDD between different brands of non-breath-activated nebulizer. In future, consideration should be given to revision of the test protocols included in the guidelines

  18. Interaction of sequential stimuli applied during the relative refractory period in relation to determination of fibrillation threshold in the canine ventricle.

    Science.gov (United States)

    Tamargo, J; Moe, B; Moe, G K

    1975-11-01

    An ineffective stimulus applied to cardiac tissue within the relative refractory period can alter the response to an immediately subsequent stimulus. We observed three response patterns that can coexist at different sites of stimulation in the same heart. In the first pattern, a stimulus of two to ten times diastolic threshold, applied too early to elicit a propagated response, becomes effective when a stimulus of equal strength is delivered 10 msec earlier. In the second pattern, a stimulus applied just late enough to evoke a response fails to do so when a stimulus of equal strenght precedes it by as much as 30 msec. Finally, in the third pattern, two stimuli, separated by 10 msec, both of which are late enough to be effective when they are given alone, fail to yield a propagated response when they are applied together. These results have a bearing on the use of trains of stimuli to assess the ventricular fibrillation threshold. Possible interpretations are based on the temporal dispersion of recovery from the refractory state.

  19. Solute clearance in CRRT: prescribed dose versus actual delivered dose.

    Science.gov (United States)

    Lyndon, William D; Wille, Keith M; Tolwani, Ashita J

    2012-03-01

    Substantial efforts have been made toward defining the dose threshold of continuous renal replacement therapy (CRRT) associated with improved survival in critically ill patients with acute kidney injury. Published studies have used prescribed effluent rates, expressed as total effluent volume (TEV) per weight and unit time (mL/kg/h), as a surrogate for dose. The purpose of this study was to compare differences in CRRT dose based on prescribed effluent rate, measured TEV and direct measurement of urea and creatinine clearance. We analyzed data that had been prospectively collected on 200 patients enrolled in a randomized trial comparing survival with a prescribed effluent rate of 20 mL/kg/h (standard dose) to 35 mL/kg/h (high dose) using pre-dilution continuous venovenous hemodiafiltration (CVVHDF). Filters were changed every 72 h. Blood urea nitrogen (BUN), serum creatinine (SCr), effluent urea nitrogen (EUN) and effluent creatinine (ECr) were collected daily. Actual delivered dose was calculated as: (EUN/BUN)*TEV for urea and (ECr/SCr)*TEV for creatinine. Data were available for 165 patients. In both groups, prescribed dose differed significantly from the measured TEV dose (P < 0.001). In the standard dose group, there was no difference between the measured TEV dose and actual delivered urea and creatinine clearances. However, in the high-dose group, measured TEV dose differed significantly from delivered urea clearance by 7.1% (P < 0.001) and creatinine clearance by 13.9% (P < 0.001). Dose based on prescribed effluent rate or measured TEV is a poor substitute for actual CVVHDF creatinine and urea clearance.

  20. Optimizing a Drone Network to Deliver Automated External Defibrillators.

    Science.gov (United States)

    Boutilier, Justin J; Brooks, Steven C; Janmohamed, Alyf; Byers, Adam; Buick, Jason E; Zhan, Cathy; Schoellig, Angela P; Cheskes, Sheldon; Morrison, Laurie J; Chan, Timothy C Y

    2017-06-20

    Public access defibrillation programs can improve survival after out-of-hospital cardiac arrest, but automated external defibrillators (AEDs) are rarely available for bystander use at the scene. Drones are an emerging technology that can deliver an AED to the scene of an out-of-hospital cardiac arrest for bystander use. We hypothesize that a drone network designed with the aid of a mathematical model combining both optimization and queuing can reduce the time to AED arrival. We applied our model to 53 702 out-of-hospital cardiac arrests that occurred in the 8 regions of the Toronto Regional RescuNET between January 1, 2006, and December 31, 2014. Our primary analysis quantified the drone network size required to deliver an AED 1, 2, or 3 minutes faster than historical median 911 response times for each region independently. A secondary analysis quantified the reduction in drone resources required if RescuNET was treated as a large coordinated region. The region-specific analysis determined that 81 bases and 100 drones would be required to deliver an AED ahead of median 911 response times by 3 minutes. In the most urban region, the 90th percentile of the AED arrival time was reduced by 6 minutes and 43 seconds relative to historical 911 response times in the region. In the most rural region, the 90th percentile was reduced by 10 minutes and 34 seconds. A single coordinated drone network across all regions required 39.5% fewer bases and 30.0% fewer drones to achieve similar AED delivery times. An optimized drone network designed with the aid of a novel mathematical model can substantially reduce the AED delivery time to an out-of-hospital cardiac arrest event. © 2017 American Heart Association, Inc.