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.

An MRI-compatible hand sensory vibrotactile system

International Nuclear Information System (INIS)

Wang, Fa; Lakshminarayanan, Kishor; Slota, Gregory P; Seo, Na Jin; Webster, John G

2015-01-01

Recently, the application of vibrotactile noise to the wrist or back of the hand has been shown to enhance fingertip tactile sensory perception (Enders et al 2013), supporting the potential for an assistive device worn at the wrist, that generates minute vibrations to help the elderly or patients with sensory deficit. However, knowledge regarding the detailed physiological mechanism behind this sensory improvement in the central nervous system, especially in the human brain, is limited, hindering progress in development and use of such assistive devices. To enable investigation of the impact of vibrotactile noise on sensorimotor brain activity in humans, a magnetic resonance imaging (MRI)-compatible vibrotactile system was developed to provide vibrotactile noise during an MRI of the brain. The vibrotactile system utilizes a remote (outside the MR room) signal amplifier which provides a voltage from –40 to +40 V to drive a 12 mm diameter piezoelectric vibrator (inside the MR room). It is portable and is found to be MRI-compatible which enables its use for neurologic investigation with MRI. The system was also found to induce an improvement in fingertip tactile sensation, consistent with the previous study. (note)

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.

Working memory for vibrotactile frequencies: comparison of cortical activity in blind and sighted individuals.

Science.gov (United States)

Burton, Harold; Sinclair, Robert J; Dixit, Sachin

2010-11-01

In blind, occipital cortex showed robust activation to nonvisual stimuli in many prior functional neuroimaging studies. The cognitive processes represented by these activations are not fully determined, although a verbal recognition memory role has been demonstrated. In congenitally blind and sighted (10 per group), we contrasted responses to a vibrotactile one-back frequency retention task with 5-s delays and a vibrotactile amplitude-change task; both tasks involved the same vibration parameters. The one-back paradigm required continuous updating for working memory (WM). Findings in both groups confirmed roles in WM for right hemisphere dorsolateral prefrontal (DLPFC) and dorsal/ventral attention components of posterior parietal cortex. Negative findings in bilateral ventrolateral prefrontal cortex suggested task performance without subvocalization. In bilateral occipital cortex, blind showed comparable positive responses to both tasks, whereas WM evoked large negative responses in sighted. Greater utilization of attention resources in blind were suggested as causing larger responses in dorsal and ventral attention systems, right DLPFC, and persistent responses across delays between trials in somatosensory and premotor cortex. In sighted, responses in somatosensory and premotor areas showed iterated peaks matched to stimulation trial intervals. The findings in occipital cortex of blind suggest that tactile activations do not represent cognitive operations for nonverbal WM task. However, these data suggest a role in sensory processing for tactile information in blind that parallels a similar contribution for visual stimuli in occipital cortex of sighted. © 2010 Wiley-Liss, Inc.

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.

Temporal and spatio-temporal vibrotactile displays for voice fundamental frequency: an initial evaluation of a new vibrotactile speech perception aid with normal-hearing and hearing-impaired individuals.

Science.gov (United States)

Auer, E T; Bernstein, L E; Coulter, D C

1998-10-01

Four experiments were performed to evaluate a new wearable vibrotactile speech perception aid that extracts fundamental frequency (F0) and displays the extracted F0 as a single-channel temporal or an eight-channel spatio-temporal stimulus. Specifically, we investigated the perception of intonation (i.e., question versus statement) and emphatic stress (i.e., stress on the first, second, or third word) under Visual-Alone (VA), Visual-Tactile (VT), and Tactile-Alone (TA) conditions and compared performance using the temporal and spatio-temporal vibrotactile display. Subjects were adults with normal hearing in experiments I-III and adults with severe to profound hearing impairments in experiment IV. Both versions of the vibrotactile speech perception aid successfully conveyed intonation. Vibrotactile stress information was successfully conveyed, but vibrotactile stress information did not enhance performance in VT conditions beyond performance in VA conditions. In experiment III, which involved only intonation identification, a reliable advantage for the spatio-temporal display was obtained. Differences between subject groups were obtained for intonation identification, with more accurate VT performance by those with normal hearing. Possible effects of long-term hearing status are discussed.

An Enhanced Soft Vibrotactile Actuator Based on ePVC Gel with Silicon Dioxide Nanoparticles.

Science.gov (United States)

Park, Won-Hyeong; Shin, Eun-Jae; Yun, Sungryul; Kim, Sang-Youn

2018-01-01

In this paper, we propose a soft vibrotactile actuator made by mixing silicon dioxide nanoparticles and plasticized PVC gel. The effect of the silicon dioxide nanoparticles in the plasticized PVC gel for the haptic performance is investigated in terms of electric, dielectric, and mechanical properties. Furthermore, eight soft vibrotactile actuators are prepared as a function of the content. Experiments are conducted to examine the haptic performance of the prepared eight soft vibrotactile actuators and to find the best weight ratio of the plasticized PVC gel to the nanoparticles. The experiments should show that the plasticized PVC gel with silicon dioxide nanoparticles improves the haptic performance of the plasticized PVC gel-based vibrotactile actuator, and the proposed vibrotactile actuator can create a variety of haptic sensations in a wide frequency range.

A quantitative method for determining spatial discriminative capacity

Directory of Open Access Journals (Sweden)

Dennis Robert G

2008-03-01

Full Text Available Abstract Background The traditional two-point discrimination (TPD test, a widely used tactile spatial acuity measure, has been criticized as being imprecise because it is based on subjective criteria and involves a number of non-spatial cues. The results of a recent study showed that as two stimuli were delivered simultaneously, vibrotactile amplitude discrimination became worse when the two stimuli were positioned relatively close together and was significantly degraded when the probes were within a subject's two-point limen. The impairment of amplitude discrimination with decreasing inter-probe distance suggested that the metric of amplitude discrimination could possibly provide a means of objective and quantitative measurement of spatial discrimination capacity. Methods A two alternative forced-choice (2AFC tracking procedure was used to assess a subject's ability to discriminate the amplitude difference between two stimuli positioned at near-adjacent skin sites. Two 25 Hz flutter stimuli, identical except for a constant difference in amplitude, were delivered simultaneously to the hand dorsum. The stimuli were initially spaced 30 mm apart, and the inter-stimulus distance was modified on a trial-by-trial basis based on the subject's performance of discriminating the stimulus with higher intensity. The experiment was repeated via sequential, rather than simultaneous, delivery of the same vibrotactile stimuli. Results Results obtained from this study showed that the performance of the amplitude discrimination task was significantly degraded when the stimuli were delivered simultaneously and were near a subject's two-point limen. In contrast, subjects were able to correctly discriminate between the amplitudes of the two stimuli when they were sequentially delivered at all inter-probe distances (including those within the two-point limen, and improved when an adapting stimulus was delivered prior to simultaneously delivered stimuli. Conclusion

Vibrotactile in-vehicle navigation system

NARCIS (Netherlands)

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

2004-01-01

A vibrotactile display, consisting ofeight vibrating elements or tactors mounted in a driver's seat, was tested in a driving simulator. Participants drove with visual, tactile and multimodal navigation displays through a built-up area. Workload and the reaction time to navigation messages were

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...

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.

A novel vibrotactile system for stimulating the glabrous skin of awake freely behaving rats during operant conditioning.

Science.gov (United States)

Devecioğlu, İsmail; Güçlü, Burak

2015-03-15

Rat skin is innervated by mechanoreceptive fibers similar to those in other mammals. Tactile experiments with behaving rats mostly focus on the vibrissal system which does not exist in humans. The aim of this study was to design and implement a novel vibrotactile system to stimulate the glabrous skin of behaving rats during operant conditioning. A computer-controlled vibrotactile system was developed for various tasks in which the volar surface of unrestrained rats' fore- and hindpaws was stimulated in an operant chamber. The operant chamber was built from off-the-shelf components. A highly accurate electrodynamic shaker with a novel multi-probe design was used for generating mechanical displacements. Twenty-five rats were trained for four sequential tasks: (A) middle-lever (trial start signal) press, (B) side-lever press with an associated visual cue, (C) similar to (B) with the addition of an auditory/tactile stimulus, (D) auditory/tactile detection (yes/no) task. Out of 9 rats which could complete the tactile version of this training schedule, 5 had over 70% accuracy in the tactile version of the detection task. Unlike actuators for stimulating whiskers, this system does not require a particular head/body alignment and can be used with freely behaving animals. The vibrotactile system was found to be effective for conditioning freely behaving rats based on stimuli applied on the glabrous skin. However, detection accuracies were lower compared to those in tasks involving whisker stimulation reported previously, probably due to differences in cortical processing. Copyright © 2015 Elsevier B.V. All rights reserved.

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, body axis, thereby eliciting canal reflexes without concordant otolith or visual cues. A simple 4 tactor system was implemented to provide feedback when tilt position exceeded predetermined levels in either device. Closed-loop nulling tasks are performed during random tilt steps or sum-of-sines (TTS only) with and without vibrotactile feedback of chair position. RESULTS. On landing day the manual control performance without vibrotactile feedback was reduced by >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.

Vibrotactile masking through the body.

Science.gov (United States)

D'Amour, Sarah; Harris, Laurence R

2014-09-01

Touches on one hand or forearm can affect tactile sensitivity at contralateral locations on the opposite side of the body. These interactions suggest an intimate connection between the two sides of the body. Here, we explore the effect of masking not across the body but through the body by measuring the effect of a masking stimulus on the back on the tactile sensitivity of the corresponding point on the front. Tactile sensitivity was measured on each side of the stomach, while vibrotactile masking stimulation was applied to one side of the front and to points on the back including the point directly behind the test point on the front. Results were compared to sensitivity, while vibrotactile stimulation was applied to a control site on the shoulder. A reduction in sensitivity of about .8 dB was found that required the masking stimulus to be within about 2 cm of the corresponding point on the back.

Conveying facial expressions to blind and visually impaired persons through a wearable vibrotactile device.

Science.gov (United States)

Buimer, Hendrik P; Bittner, Marian; Kostelijk, Tjerk; van der Geest, Thea M; Nemri, Abdellatif; van Wezel, Richard J A; Zhao, Yan

2018-01-01

In face-to-face social interactions, blind and visually impaired persons (VIPs) lack access to nonverbal cues like facial expressions, body posture, and gestures, which may lead to impaired interpersonal communication. In this study, a wearable sensory substitution device (SSD) consisting of a head mounted camera and a haptic belt was evaluated to determine whether vibrotactile cues around the waist could be used to convey facial expressions to users and whether such a device is desired by VIPs for use in daily living situations. Ten VIPs (mean age: 38.8, SD: 14.4) and 10 sighted persons (SPs) (mean age: 44.5, SD: 19.6) participated in the study, in which validated sets of pictures, silent videos, and videos with audio of facial expressions were presented to the participant. A control measurement was first performed to determine how accurately participants could identify facial expressions while relying on their functional senses. After a short training, participants were asked to determine facial expressions while wearing the emotion feedback system. VIPs using the device showed significant improvements in their ability to determine which facial expressions were shown. A significant increase in accuracy of 44.4% was found across all types of stimuli when comparing the scores of the control (mean±SEM: 35.0±2.5%) and supported (mean±SEM: 79.4±2.1%) phases. The greatest improvements achieved with the support of the SSD were found for silent stimuli (68.3% for pictures and 50.8% for silent videos). SPs also showed consistent, though not statistically significant, improvements while supported. Overall, our study shows that vibrotactile cues are well suited to convey facial expressions to VIPs in real-time. Participants became skilled with the device after a short training session. Further testing and development of the SSD is required to improve its accuracy and aesthetics for potential daily use.

Effect of friction on vibrotactile sensation of normal and dehydrated skin.

Science.gov (United States)

Chen, S; Ge, S; Tang, W; Zhang, J

2016-02-01

Vibrotactile sensation mediated is highly dependent on surface mechanical and frictional properties. Dehydration of skin could change these properties. To investigate the relationship between friction and vibrotactile sensation of normal and dehydrated skin. Vibrations were firstly measured during surface exploration using a biomimetic sensor. Piglet skin was used as human skin model to study frictional properties for both normal and dehydrated skin using an atomic force microscope on nanoscale and a pin-on-disk tribometer on macroscale. Effect of vibrational frequency on friction and vibrotactile perception was also observed on nano and macro scale for normal and dehydrated skin. The result indicated that dehydrated skin was less sensitive than normal skin. The coefficient of friction of dehydrated skin is smaller than that of normal skin on both nano and macro scale. The coefficient of friction increases as increasing scanning frequencies. There is a positive correlation between coefficient of friction and vibrotactile sensation on nanoscale and macroscale. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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,

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).

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.

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.

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...

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

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.

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

International Nuclear Information System (INIS)

Barbacena, I L; Barros, A T; Freire, R C S; Vieira, E C A

2007-01-01

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

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

OpenAIRE

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 Haptics player can store up to ten different compositions made up of haptic signals varying in amplitude, waveform and length. We use these different compositions to explore the aesthetic potential o...

Vibrotactile tilt feedback improves dynamic gait index: a fall risk indicator in older adults.

Science.gov (United States)

Wall, Conrad; Wrisley, Diane M; Statler, Kennyn D

2009-07-01

The purpose of this study was to determine the effectiveness of vibrotactile feedback of body tilt in improving dynamic gait index (DGI) a fall risk indicator in community dwelling older adults. Twelve healthy elderly subjects (three males and nine females, age 79.7+/-5.4 yrs) were tested in an institutional balance rehabilitation laboratory to investigate changes between the feedback off and on conditions. Subjects were acutely exposed to a vibrotactile display that indicated the magnitude and direction of their body tilt from the vertical. DGI and mediolateral (ML) sway were determined during locomotion with, and without, vibrotactile tilt feedback (VTTF). All subjects were at risk for falls based on their initial DGI Score (range: 15-19, mean 17.4+/-1.56), which was taken with the vibratory stimulus turned off. Subjects learned to use the trunk tilt information from the vibrotactile feedback vest through 20-30 min of gait and balance training consisting of activities that challenged their balance. Subjects were then retested on the DGI. Statistically significant changes were demonstrated for the DGI total score while using the vibrotactile tilt feedback. DGI total scores improved from 17.1+/-0.4 to 20.8+/-0.3 (pfall risk indicators for this population.

Vibrotactile feedback for conveying object shape information as perceived by artificial sensing of robotic arm.

Science.gov (United States)

Khasnobish, Anwesha; Pal, Monalisa; Sardar, Dwaipayan; Tibarewala, D N; Konar, Amit

2016-08-01

This work is a preliminary study towards developing an alternative communication channel for conveying shape information to aid in recognition of items when tactile perception is hindered. Tactile data, acquired during object exploration by sensor fitted robot arm, are processed to recognize four basic geometric shapes. Patterns representing each shape, classified from tactile data, are generated using micro-controller-driven vibration motors which vibrotactually stimulate users to convey the particular shape information. These motors are attached on the subject's arm and their psychological (verbal) responses are recorded to assess the competence of the system to convey shape information to the user in form of vibrotactile stimulations. Object shapes are classified from tactile data with an average accuracy of 95.21 %. Three successive sessions of shape recognition from vibrotactile pattern depicted learning of the stimulus from subjects' psychological response which increased from 75 to 95 %. This observation substantiates the learning of vibrotactile stimulation in user over the sessions which in turn increase the system efficacy. The tactile sensing module and vibrotactile pattern generating module are integrated to complete the system whose operation is analysed in real-time. Thus, the work demonstrates a successful implementation of the complete schema of artificial tactile sensing system for object-shape recognition through vibrotactile stimulations.

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.

Vibrotactile Stimulation: A Future Clinical Tool for Speech Pathologists

Science.gov (United States)

Telage, Kal; Fucci, Donald

1973-01-01

Presented is a rationale for using vibrotactile stimulation (vibration applied to oral structures) as a diagnostic instrument to assess oral-sensory deficits which may contribute to defective speech patterns. (Author/LS)

Identification of neural structures involved in stuttering using vibrotactile feedback.

Science.gov (United States)

Cheadle, Oliver; Sorger, Clarissa; Howell, Peter

Feedback delivered over auditory and vibratory afferent pathways has different effects on the fluency of people who stutter (PWS). These features were exploited to investigate the neural structures involved in stuttering. The speech signal vibrated locations on the body (vibrotactile feedback, VTF). Eleven PWS read passages under VTF and control (no-VTF) conditions. All combinations of vibration amplitude, synchronous or delayed VTF and vibrator position (hand, sternum or forehead) were presented. Control conditions were performed at the beginning, middle and end of test sessions. Stuttering rate, but not speaking rate, differed between the control and VTF conditions. Notably, speaking rate did not change between when VTF was delayed versus when it was synchronous in contrast with what happens with auditory feedback. This showed that cerebellar mechanisms, which are affected when auditory feedback is delayed, were not implicated in the fluency-enhancing effects of VTF, suggesting that there is a second fluency-enhancing mechanism. Copyright © 2018 Elsevier Inc. All rights reserved.

Optimum Operating Conditions for PZT Actuators for Vibrotactile Wearables

Science.gov (United States)

Logothetis, Irini; Matsouka, Dimitra; Vassiliadis, Savvas; Vossou, Clio; Siores, Elias

2018-04-01

Recently, vibrotactile wearables have received much attention in fields such as medicine, psychology, athletics and video gaming. The electrical components presently used to generate vibration are rigid; hence, the design and creation of ergonomical wearables are limited. Significant advances in piezoelectric components have led to the production of flexible actuators such as piezoceramic lead zirconate titanate (PZT) film. To verify the functionality of PZT actuators for use in vibrotactile wearables, the factors influencing the electromechanical conversion were analysed and tested. This was achieved through theoretical and experimental analyses of a monomorph clamped-free structure for the PZT actuator. The research performed for this article is a three-step process. First, a theoretical analysis presents the equations governing the actuator. In addition, the eigenfrequency of the film was analysed preceding the experimental section. For this stage, by applying an electric voltage and varying the stimulating electrical characteristics (i.e., voltage, electrical waveform and frequency), the optimum operating conditions for a PZT film were determined. The tip displacement was measured referring to the mechanical energy converted from electrical energy. From the results obtained, an equation for the mechanical behaviour of PZT films as actuators was deduced. It was observed that the square waveform generated larger tip displacements. In conjunction with large voltage inputs at the predetermined eigenfrequency, the optimum operating conditions for the actuator were achieved. To conclude, PZT films can be adapted to assist designers in creating comfortable vibrotactile wearables.

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.

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...

A novel device for the study of somatosensory information processing

Science.gov (United States)

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

2012-01-01

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 stimulator and the limitations that were inherent in that device, we designed and fabricated a four-site stimulator that provides a number of advantages over the previous version. First, the device can stimulate four independent skin sites and is primarily designed for stimulating the digit tips. Second, the positioning of the probe tips has been re-designed to provide better ergonomic hand placement. Third, the device is much more portable than the previously-reported stimulator. Fourth, the stimulator head has a much smaller footprint on the table or surface where it resides. To demonstrate the capacity of the device for delivering tactile stimulation at four independent sites, a finger agnosia protocol, in the presence and absence of conditioning stimuli, was conducted on seventeen healthy control subjects. The study demonstrated that with increasing amplitudes of vibrotactile conditioning stimuli concurrent with the agnosia test, inaccuracies of digit identification increased, particularly at digits D3 and D4. The results are consistent with prior studies that implicated synchronization of adjacent and near-adjacent cortical ensembles with conditioning stimuli in impacting TOJ performance (Tommerdahl et al., 2007). PMID:22155443

Vibrotactile Feedback Alters Dynamics Of Static Postural Control In Persons With Parkinson's Disease But Not Older Adults At High Fall Risk.

Science.gov (United States)

High, Carleigh M; McHugh, Hannah F; Mills, Stephen C; Amano, Shinichi; Freund, Jane E; Vallabhajosula, Srikant

2018-06-01

Aging and Parkinson's disease are often associated with impaired postural control. Providing extrinsic feedback via vibrotactile sensation could supplement intrinsic feedback to maintain postural control. We investigated the postural control response to vibrotactile feedback provided at the trunk during challenging stance conditions in older adults at high fall risk and individuals with Parkinson's disease compared to healthy older adults. Nine older adults at high fall risk, 9 persons with Parkinson's disease and 10 healthy older adults performed 30s quiet standing on a force platform under five challenging stance conditions with eyes open/closed and standing on firm/foam surface with feet together, each with and without vibrotactile feedback. During vibrotactile feedback trials, feedback was provided when participants swayed >10% over the center of their base of support. Participants were instructed vibrations would be in response to their movement. Magnitude of postural sway was estimated using center of pressure path length, velocity, and sway area. Dynamics of individuals' postural control was evaluated using detrended fluctuation analysis. Results showed that vibrotactile feedback induced a change in postural control dynamics among persons with Parkinson's disease when standing with intact intrinsic visual input and altered intrinsic somatosensory input, but there was no change in sway magnitude. However, use of vibrotactile feedback did not significantly alter dynamics of postural control in older adults with high risk of falling or reduce the magnitude of sway. Considering the effects of vibrotactile feedback were dependent on the population and stance condition, designing an optimal therapeutic regimen for balance training should be carefully considered and be specific to a target population. Furthermore, our results suggest that explicit instructions on how to respond to the vibrotactile feedback could affect training outcome. Copyright © 2018 The

Miniaturized 3 × 3 array film vibrotactile actuator made with cellulose acetate for virtual reality simulators

International Nuclear Information System (INIS)

Ko, Hyun-U; Chan Kim, Hyun; Kim, Jaehwan; Kim, Sang-Youn

2015-01-01

This paper reports an array vibrotactile actuator which is suitable for fitting into virtual reality simulators. A 3 × 3 array actuator, of size 15 × 15 × 1 mm 3 , consists of nine cantilever structured cells of which the pillars are supported and made with cellulose acetate by a molding technique. The fabrication process and performance test along with results for the suggested vibrotactile actuator are explained. To simulate the touch force, the top mass is added on the actuator and the actuator performance is measured under actuation. When 2000 V p–p voltage is applied to the actuator, the averaged maximum acceleration for all cells is 0.44 ± 0.19 g, which is above the vibrotactile threshold. The actuation mechanism is associated with the electrostatic force between top and bottom electrodes. (paper)

Frequency-specific masking effect by vibrotactile stimulation to the forearm

NARCIS (Netherlands)

Tanaka, Y.; Matsuoka, S.; Bergmann Tiest, W.M.; Kappers, A.M.L.; Minamizawa, K.; Sano, A.; Bello, F.; Kajimoto, H.; Visell, Y.

2016-01-01

This paper demonstrates frequency-specific masking of tactile sensations on the index finger by remote vibrotactile stimulation. A vibration of 50 Hz was presented to the index finger. In three experimental conditions, the detection threshold for this vibration was determined with a masking

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.

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

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......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...

Cerebral asymmetry in the control of cardiovascular functioning: evidence from lateral vibrotactile stimulation.

Science.gov (United States)

Foster, Paul S; Hubbard, Tyler; Yung, Raegan C; Ferguson, Brad J; Drago, Valeria; Harrison, David W

2013-01-01

Research has supported hemispheric specialisation in the regulation of cardiovascular functioning, with the left hemisphere being associated with parasympathetic functioning and the right hemisphere with sympathetic functioning. We sought to investigate this relationship further using vibrotactile stimulation applied to the palms. Our prediction was that vibrotactile stimulation applied to the left hand would result in increased heart rate and blood pressure, and that stimulation applied to the right hand would result in decreased heart rate and blood pressure. The results indicated significant differences in heart rate change scores in the predicted direction. No differences were noted for systolic or diastolic blood pressure. Hence the findings provide partial support for the lateralisation of autonomic functions.

Age-related loss in attention-based modulation of tactile stimuli at early stages of somatosensory processing.

Science.gov (United States)

Bolton, David A E; Staines, W Richard

2012-06-01

Normal aging has been linked to impairments in gating of irrelevant sensory information and neural markers of diminished cognitive processing. Whilst much of the research in this area has focussed on visual and auditory modalities it is unclear to what degree these findings apply to somatosensation. Therefore we investigated how age impacts early event-related potentials (ERPs) arising from relevant or irrelevant vibrotactile stimuli to the fingertips. Specifically, we hypothesised that older adults would demonstrate reduced attention-based modulation of tactile ERPs generated at early stages of cortical somatosensory processing. In accord with previous research we also expected to observe diminished P300 responses to attended targets and behavioural deficits. Participants received vibrotactile stimulation to the second and fifth digit on the left hand and reported target stimuli on one digit only (as instructed) with comparisons between two age groups: (1) Young adults (age range 20-39) and (2) Older adults (age range 62-89). ERP amplitudes for the P50, N70, P100, N140 and long latency positivity (LLP) were quantified for attended and non-attended trials at several electrodes (C4, CP4, CP3 and FC4). The P300 in response to attended target stimuli was measured at CPZ. There was no effect of attention on the P50 and N70 however the P100, N140 and LLP were modulated with attention. In both age groups the P100 and LLP were more positive during trials where the stimuli were attended to, whilst the N140 was enhanced for non-attended stimuli. Comparisons between groups revealed a reduction in P100 attention-based modulation for the older adults versus the young adults. This effect was due to a loss of suppression of the non-attended stimuli in older subjects. Moreover, the P300 was both slower and reduced in peak amplitude for older subjects in response to attended targets. Finally, older adults demonstrated impaired performance in terms of both reduced target detection

Remote vibrotactile noise improves light touch sensation in stroke survivors' fingertips via stochastic resonance.

Science.gov (United States)

Enders, Leah R; Hur, Pilwon; Johnson, Michelle J; Seo, Na Jin

2013-10-11

Stroke rehabilitation does not often integrate both sensory and motor recovery. While subthreshold noise was shown to enhance sensory signal detection at the site of noise application, having a noise-generating device at the fingertip to enhance fingertip sensation and potentially enhance dexterity for stroke survivors is impractical, since the device would interfere with object manipulation. This study determined if remote application of subthreshold vibrotactile noise (away from the fingertips) improves fingertip tactile sensation with potential to enhance dexterity for stroke survivors. Index finger and thumb pad sensation was measured for ten stroke survivors with fingertip sensory deficit using the Semmes-Weinstein Monofilament and Two-Point Discrimination Tests. Sensation scores were measured with noise applied at one of three intensities (40%, 60%, 80% of the sensory threshold) to one of four locations of the paretic upper extremity (dorsal hand proximal to the index finger knuckle, dorsal hand proximal to the thumb knuckle, dorsal wrist, volar wrist) in a random order, as well as without noise at beginning (Pre) and end (Post) of the testing session. Vibrotactile noise of all intensities and locations instantaneously and significantly improved Monofilament scores of the index fingertip and thumb tip (p sensation, independent of noise location and intensity. Vibrotactile noise at the wrist and dorsal hand may have enhanced the fingertips' light touch sensation via stochastic resonance and interneuronal connections. While long-term benefits of noise in stroke patients warrants further investigation, this result demonstrates potential that a wearable device applying vibrotactile noise at the wrist could enhance sensation and grip ability without interfering with object manipulation in everyday tasks.

Vibrotactile stimulation: A non-pharmacological intervention for opioid-exposed newborns.

Directory of Open Access Journals (Sweden)

Ian Zuzarte

Full Text Available To examine the therapeutic potential of stochastic vibrotactile stimulation (SVS as a complementary non-pharmacological intervention for withdrawal in opioid-exposed newborns.A prospective, within-subjects single-center study was conducted in 26 opioid-exposed newborns (>37 weeks; 16 male hospitalized since birth and treated pharmacologically for Neonatal Abstinence Syndrome. A specially-constructed mattress delivered low-level SVS (30-60Hz, 10-12μm RMS, alternated in 30-min intervals between continuous vibration (ON and no vibration (OFF over a 6-8 hr session. Movement activity, heart rate, respiratory rate, axillary temperature and blood-oxygen saturation were calculated separately for ON and OFF.There was a 35% reduction in movement activity with SVS (p30 sec duration for ON than OFF (p = 0.003. Incidents of tachypneic breaths and tachycardic heart beats were each significantly reduced with SVS, whereas incidents of eupneic breaths and eucardic heart beats each significantly increased with SVS (p<0.03. Infants maintained body temperature and arterial-blood oxygen level independent of stimulation condition.SVS reduced hyperirritability and pathophysiological instabilities commonly observed in pharmacologically-managed opioid-exposed newborns. SVS may provide an effective complementary therapeutic intervention for improving autonomic function in newborns with Neonatal Abstinence Syndrome.

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.

Vibrotactile Compliance Feedback for Tangential Force Interaction.

Science.gov (United States)

Heo, Seongkook; Lee, Geehyuk

2017-01-01

This paper presents a method to generate a haptic illusion of compliance using a vibrotactile actuator when a tangential force is applied to a rigid surface. The novel method builds on a conceptual compliance model where a physical object moves on a textured surface in response to a tangential force. The method plays vibration patterns simulating friction-induced vibrations as an applied tangential force changes. We built a prototype consisting of a two-dimensional tangential force sensor and a surface transducer to test the effectiveness of the model. Participants in user experiments with the prototype perceived the rigid surface of the prototype as a moving, rubber-like plate. The main findings of the experiments are: 1) the perceived stiffness of a simulated material can be controlled by controlling the force-playback transfer function, 2) its perceptual properties such as softness and pleasantness can be controlled by changing friction grain parameters, and 3) the use of the vibrotactile compliance feedback reduces participants' workload including physical demand and frustration while performing a force repetition task.

Development of Cell Culture Microdevice Actuated by Piezoelectric Thin Films for Delivering Mechanical Vibratory Stimuli to Cells

International Nuclear Information System (INIS)

Yamada, Y; Umegaki, G; Kawashima, T; Nagai, M; Shibata, T; Masuzawa, T; Kimura, T; Kishida, A

2012-01-01

In order to realize a cell culture microdevice actuated by piezoelectric thin films for on-chip regulation of cell functions, this paper reported on a feasibility study by using the microdevice with KOH-etched cavities surrounded by four (111) sidewalls as microchambers in order to introduce cells to be cultured. As a result, the vibration characteristic of the PZT actuator was improved by using an electric field -150 kV/cm at 70 C for 30 min in poling process. A feasibility study on cell culture for delivering mechanical vibratory stimuli to cells revealed the microdevice could be applicable to the culture with actual biological cells. In addition, it was found that O 2 -plasma treated parylene-C process could be applicable for obtaining homogeneous surface of cell culture microdevice.

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

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....

Development of a flexible and bendable vibrotactile actuator based on wave-shaped poly(vinyl chloride)/acetyl tributyl citrate gels for wearable electronic devices

Science.gov (United States)

Park, Won-Hyeong; Bae, Jin Woo; Shin, Eun-Jae; Kim, Sang-Youn

2016-11-01

The paradigm of consumer electronic devices is being shifted from rigid hand-held devices to flexible/wearable devices in search of benefits such as enhanced usability and portability, excellent wear characteristics, and more functions in less space. However, the fundamental incompatibility of flexible/wearable devices and a rigid actuator brought forth a new issue obstructing commercialization of flexible/wearable devices. In this paper, we propose a new wave-shaped eco-friendly PVC gel, and a new flexible and bendable vibrotactile actuator that could easily be applied to wearable electronic devices. We explain the vibration mechanism of the proposed vibrotactile actuator and investigate its influence on the content of plasticizer for the performance of the proposed actuator. An experiment for measuring vibrational amplitude was conducted over a wide frequency range. The experiment clearly showed that the proposed vibrotactile actuator could create a variety of haptic sensations in wearable devices.

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.

Sustained Attention in Auditory and Visual Monitoring Tasks: Evaluation of the Administration of a Rest Break or Exogenous Vibrotactile Signals.

Science.gov (United States)

Arrabito, G Robert; Ho, Geoffrey; Aghaei, Behzad; Burns, Catherine; Hou, Ming

2015-12-01

Performance and mental workload were observed for the administration of a rest break or exogenous vibrotactile signals in auditory and visual monitoring tasks. Sustained attention is mentally demanding. Techniques are required to improve observer performance in vigilance tasks. Participants (N = 150) monitored an auditory or a visual display for changes in signal duration in a 40-min watch. During the watch, participants were administered a rest break or exogenous vibrotactile signals. Detection accuracy was significantly greater in the auditory than in the visual modality. A short rest break restored detection accuracy in both sensory modalities following deterioration in performance. Participants experienced significantly lower mental workload when monitoring auditory than visual signals, and a rest break significantly reduced mental workload in both sensory modalities. Exogenous vibrotactile signals had no beneficial effects on performance, or mental workload. A rest break can restore performance in auditory and visual vigilance tasks. Although sensory differences in vigilance tasks have been studied, this study is the initial effort to investigate the effects of a rest break countermeasure in both auditory and visual vigilance tasks, and it is also the initial effort to explore the effects of the intervention of a rest break on the perceived mental workload of auditory and visual vigilance tasks. Further research is warranted to determine exact characteristics of effective exogenous vibrotactile signals in vigilance tasks. Potential applications of this research include procedures for decreasing the temporal decline in observer performance and the high mental workload imposed by vigilance tasks. © 2015, Her Majesty the Queen in Right of Canada, as represented by the Minister of National Defence.

Gamma and Beta Oscillations in Human MEG Encode the Contents of Vibrotactile Working Memory

Directory of Open Access Journals (Sweden)

Alexander H. von Lautz

2017-12-01

Full Text Available Ample evidence suggests that oscillations in the beta band represent quantitative information about somatosensory features during stimulus retention. Visual and auditory working memory (WM research, on the other hand, has indicated a predominant role of gamma oscillations for active WM processing. Here we reconciled these findings by recording whole-head magnetoencephalography during a vibrotactile frequency comparison task. A Braille stimulator presented healthy subjects with a vibration to the left fingertip that was retained in WM for comparison with a second stimulus presented after a short delay. During this retention interval spectral power in the beta band from the right intraparietal sulcus and inferior frontal gyrus (IFG monotonically increased with the to-be-remembered vibrotactile frequency. In contrast, induced gamma power showed the inverse of this pattern and decreased with higher stimulus frequency in the right IFG. Together, these results expand the previously established role of beta oscillations for somatosensory WM to the gamma band and give further evidence that quantitative information may be processed in a fronto-parietal network.

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.

Recognition memory for vibrotactile rhythms: an fMRI study in blind and sighted individuals.

Science.gov (United States)

Sinclair, Robert J; Dixit, Sachin; Burton, Harold

2011-01-01

Calcarine sulcal cortex possibly contributes to semantic recognition memory in early blind (EB). We assessed a recognition memory role using vibrotactile rhythms and a retrieval success paradigm involving learned "old" and "new" rhythms in EB and sighted. EB showed no activation differences in occipital cortex indicating retrieval success but replicated findings of somatosensory processing. Both groups showed retrieval success in primary somatosensory, precuneus, and orbitofrontal cortex. The S1 activity might indicate generic sensory memory processes.

Comparison of Verbal Preference Assessments in the Presence and Absence of the Actual Stimuli

Science.gov (United States)

Kuhn, David E.; DeLeon, Iser G.; Terlonge, Cindy; Goysovich, Richard

2006-01-01

Stimulus preference assessments for individuals with developmental disabilities typically involve offering choices among stimuli and providing immediate access to the chosen stimuli. Several researchers have explored the utility of presenting choices verbally, thereby obviating the need to present the choices in tangible form and deliver access to…

Immediate effect of subliminal priming with positive reward stimuli on standing balance in healthy individuals

OpenAIRE

Aoyama, Yasuhiro; Uchida, Hiroyuki; Sugi, Yasuyuki; Kawakami, Akinobu; Fujii, Miki; Kiso, Kanae; Kono, Ryota; Takebayashi, Takashi; Hirao, Kazuki

2017-01-01

Abstract Background: Information received subconsciously can influence exercise performance; however, it remains unclear whether subliminal or supraliminal reward is more effective in improving standing balance ability when priming stimuli are subconsciously delivered. The present study aimed to compare the effects of subliminal priming-plus-subliminal reward stimuli (experimental) with subliminal priming-plus-supraliminal reward stimuli (control) on standing balance ability. Methods: This wa...

Neurosensory sequelae assessed by thermal and vibrotactile perception thresholds after local cold injury.

Science.gov (United States)

Carlsson, Daniel; Burström, Lage; Lilliesköld, Victoria Heldestad; Nilsson, Tohr; Nordh, Erik; Wahlström, Jens

2014-01-01

Local freezing cold injuries are common in the north and sequelae to cold injury can persist many years. Quantitative sensory testing (QST) can be used to assess neurosensory symptoms but has previously not been used on cold injury patients. To evaluate neurosensory sequelae after local freezing cold injury by thermal and vibrotactile perception thresholds and by symptom descriptions. Fifteen patients with a local freezing cold injury in the hands or feet, acquired during military training, were studied with QST by assessment of vibrotactile (VPT), warmth (WPT) and cold (CPT) perception thresholds 4 months post-injury. In addition, a follow-up questionnaire, focusing on neurovascular symptoms, was completed 4 months and 4 years post-injury. QST demonstrated abnormal findings in one or both affected hands for VPT in 6 patients, for WPT in 4 patients and for CPT in 1 patient. In the feet, QST was abnormal for VPT in one or both affected feet in 8 patients, for WPT in 6 patients and for CPT in 4 patients. Freezing cold injury related symptoms, e.g. pain/discomfort when exposed to cold, cold sensation and white fingers were common at 4 months and persisted 4 years after the initial injury. Neurosensory sequelae after local freezing cold injury, in terms of abnormal thermal and/or vibration perception thresholds, may last at least 4 months after the initial injury. Symptoms such as pain/discomfort at cold exposure, cold sensations and white fingers may persist at least 4 years after the initial injury.

Effects of acoustical stimuli delivered through hearing aids on tinnitus.

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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.

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

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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.

Which limb is it? Responses to vibrotactile stimulation in early infancy.

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Somogyi, Eszter; Jacquey, Lisa; Heed, Tobias; Hoffmann, Matej; Lockman, Jeffrey J; Granjon, Lionel; Fagard, Jacqueline; O'Regan, J Kevin

2017-12-11

This study focuses on how the body schema develops during the first months of life, by investigating infants' motor responses to localized vibrotactile stimulation on their limbs. Vibrotactile stimulation was provided by small buzzers that were attached to the infants' four limbs one at a time. Four age groups were compared cross-sectionally (3-, 4-, 5-, and 6-month-olds). We show that before they actually reach for the buzzer, which, according to previous studies, occurs around 7-8 months of age, infants demonstrate emerging knowledge about their body's configuration by producing specific movement patterns associated with the stimulated body area. At 3 months, infants responded with an increase in general activity when the buzzer was placed on the body, independently of the vibrator's location. Differentiated topographical awareness of the body seemed to appear around 5 months, with specific responses resulting from stimulation of the hands emerging first, followed by the differentiation of movement patterns associated with the stimulation of the feet. Qualitative analyses revealed specific movement types reliably associated with each stimulated location by 6 months of age, possibly preparing infants' ability to actually reach for the vibrating target. We discuss this result in relation to newborns' ability to learn specific movement patterns through intersensory contingency. Statement of contribution what is already known on infants' sensorimotor knowledge about their own bodies 3-month-olds readily learn to produce specific limb movements to obtain a desired effect (movement of a mobile). infants detect temporal and spatial correspondences between events involving their own body and visual events. what the present study adds until 4-5 months of age, infants mostly produce general motor responses to localized touch. this is because in the present study, infants could not rely on immediate contingent feedback. we propose a cephalocaudal developmental trend of

Vibrotactile neurofeedback balance training in patients with Parkinson's disease: reducing the number of falls.

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Rossi-Izquierdo, Marcos; Ernst, Arne; Soto-Varela, Andrés; Santos-Pérez, Sofía; Faraldo-García, Ana; Sesar-Ignacio, Angel; Basta, Dietmar

2013-02-01

The aim of this study was to assess effectiveness of balance training with a vibrotactile neurofeedback system in improving overall stability in patients with Parkinson's disease (PD). Ten patients diagnosed with idiopathic PD were included. Individualization of the rehabilitation program started with a body sway analysis of stance and gait tasks (Standard Balance Deficit Test, SBDT) by using the diagnostic tool of the applied device (Vertiguard(®)-RT). Those tasks with the poorest outcome as related to age- and gender-related controls were included in the training program (not more than six tasks). Improvement of postural stability was assessed by performing SBDT, Sensory Organization Test (SOT) of Computerized Dynamic Posturography (CDP), Dizziness Handicap Inventory (DHI), activity-specific balance confidence scale and recording the number of falls over the past three months. Furthermore, scores of SOT and DHI of 10 PD patients previously trained in an earlier study (by using CDP) were compared with results of those in the present study. After neurofeedback training (NFT), there was a statistically significant improvement in body sway (calculated over all training tasks), number of falls, and scores of SOT, DHI and ABC. In comparison with CDP-training, a statistically significant higher increase of SOT score was observed for patients after NFT with the Vertiguard-RT device compared to CDP training. Our results showed that a free-field vibrotactile NFT with Vertiguard(®)-RT device can improve balance in PD patients in everyday life conditions very effectively, which might led in turn to a reduction of falls. Copyright © 2012 Elsevier B.V. All rights reserved.

Take-over again: Investigating multimodal and directional TORs to get the driver back into the loop.

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Petermeijer, Sebastiaan; Bazilinskyy, Pavlo; Bengler, Klaus; de Winter, Joost

2017-07-01

When a highly automated car reaches its operational limits, it needs to provide a take-over request (TOR) in order for the driver to resume control. The aim of this simulator-based study was to investigate the effects of TOR modality and left/right directionality on drivers' steering behaviour when facing a head-on collision without having received specific instructions regarding the directional nature of the TORs. Twenty-four participants drove three sessions in a highly automated car, each session with a different TOR modality (auditory, vibrotactile, and auditory-vibrotactile). Six TORs were provided per session, warning the participants about a stationary vehicle that had to be avoided by changing lane left or right. Two TORs were issued from the left, two from the right, and two from both the left and the right (i.e., nondirectional). The auditory stimuli were presented via speakers in the simulator (left, right, or both), and the vibrotactile stimuli via a tactile seat (with tactors activated at the left side, right side, or both). The results showed that the multimodal TORs yielded statistically significantly faster steer-touch times than the unimodal vibrotactile TOR, while no statistically significant differences were observed for brake times and lane change times. The unimodal auditory TOR yielded relatively low self-reported usefulness and satisfaction ratings. Almost all drivers overtook the stationary vehicle on the left regardless of the directionality of the TOR, and a post-experiment questionnaire revealed that most participants had not realized that some of the TORs were directional. We conclude that between the three TOR modalities tested, the multimodal approach is preferred. Moreover, our results show that directional auditory and vibrotactile stimuli do not evoke a directional response in uninstructed drivers. More salient and semantically congruent cues, as well as explicit instructions, may be needed to guide a driver into a specific

Sensing Performance of a Vibrotactile Glove for Deaf-Blind People

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Albano Carrera

2017-03-01

Full Text Available This paper presents a glove designed to assess the viability of communication between a deaf-blind user and his/her interlocutor through a vibrotactile device. This glove is part of the TactileCom system, where communication is bidirectional through a wireless link, so no contact is required between the interlocutors. Responsiveness is higher than with letter by letter wording. The learning of a small set of concepts is simpler and the amount learned can be increased at the user’s convenience. The number of stimulated fingers, the keying frequencies and finger response were studied. Message identification rate was 97% for deaf-blind individuals and 81% for control subjects. Identification by single-finger stimulation was better than by multiple-finger stimulation. The interface proved suitable for communication with deaf-blind individuals and can also be used in other conditions, such as multilingual or noisy environments.

Reward modulates oculomotor competition between differently valued stimuli.

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Bucker, Berno; Silvis, Jeroen D; Donk, Mieke; Theeuwes, Jan

2015-03-01

The present work explored the effects of reward in the well-known global effect paradigm in which two objects appear simultaneously in close spatial proximity. The experiment consisted of three phases (i) a pre-training phase that served as a baseline, (ii) a reward-training phase to associate differently colored stimuli with high, low and no reward value, and (iii) a post-training phase in which rewards were no longer delivered, to examine whether objects previously associated with higher reward value attracted the eyes more strongly than those associated with low or no reward value. Unlike previous reward studies, the differently valued objects directly competed with each other on the same trial. The results showed that initially eye movements were not biased towards any particular stimulus, while in the reward-training phase, eye movements started to land progressively closer towards stimuli that were associated with a high reward value. Even though rewards were no longer delivered, this bias remained robustly present in the post-training phase. A time course analysis showed that the effect of reward was present for the fastest saccades (around 170 ms) and increased with increasing latency. Although strategic effects for slower saccades cannot be ruled out, we suggest that fast oculomotor responses became habituated and were no longer under strategic attentional control. Together the results imply that reward affects oculomotor competition in favor of stimuli previously associated high reward, when multiple reward associated objects compete for selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Peptide-targeted, stimuli-responsive polymersomes for delivering a cancer stemness inhibitor to cancer stem cell microtumors.

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Karandish, Fataneh; Froberg, James; Borowicz, Pawel; Wilkinson, John C; Choi, Yongki; Mallik, Sanku

2018-03-01

Often cancer relapses after an initial response to chemotherapy because of the tumor's heterogeneity and the presence of progenitor stem cells, which can renew. To overcome drug resistance, metastasis, and relapse in cancer, a promising approach is the inhibition of cancer stemness. In this study, the expression of the neuropilin-1 receptor in both pancreatic and prostate cancer stem cells was identified and targeted with a stimuli-responsive, polymeric nanocarrier to deliver a stemness inhibitor (napabucasin) to cancer stem cells. Reduction-sensitive amphiphilic block copolymers PEG 1900 -S-S-PLA 6000 and the N 3 -PEG 1900 -PLA 6000 were synthesized. The tumor penetrating iRGD peptide-hexynoic acid conjugate was linked to the N 3 -PEG 1900 -PLA 6000 polymer via a Cu 2+ catalyzed "Click" reaction. Subsequently, this peptide-polymer conjugate was incorporated into polymersomes for tumor targeting and tissue penetration. We prepared polymersomes containing 85% PEG 1900 -S-S-PLA 6000 , 10% iRGD-polymer conjugate, and 5% DPPE-lissamine rhodamine dye. The iRGD targeted polymersomes encapsulating the cancer stemness inhibitor napabucasin were internalized in both prostate and pancreatic cancer stem cells. The napabucasin encapsulated polymersomes significantly (p < .05) reduced the viability of both prostate and pancreatic cancer stem cells and decreased the stemness protein expression notch-1 and nanog compared to the control and vesicles without any drug. The napabucasin encapsulated polymersome formulations have the potential to lead to a new direction in prostate and pancreatic cancer therapy by penetrating deeply into the tumors, releasing the encapsulated stemness inhibitor, and killing cancer stem cells. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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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.

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

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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.

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

Selective sensation based brain-computer interface via mechanical vibrotactile stimulation.

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Yao, Lin; Meng, Jianjun; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

2013-01-01

In this work, mechanical vibrotactile stimulation was applied to subjects' left and right wrist skins with equal intensity, and a selective sensation perception task was performed to achieve two types of selections similar to motor imagery Brain-Computer Interface. The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS. The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%. Comparative experiments with motor imagery (with and without presence of stimulation) were also carried out, which further showed the feasibility of selective sensation as an alternative BCI task complementary to motor imagery. Specifically there was significant improvement ([Formula: see text]) from near 65% in motor imagery (with and without presence of stimulation) to above 80% in selective sensation on some subjects. The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system.

Selective Sensation Based Brain-Computer Interface via Mechanical Vibrotactile Stimulation

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Yao, Lin; Meng, Jianjun; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

2013-01-01

In this work, mechanical vibrotactile stimulation was applied to subjects’ left and right wrist skins with equal intensity, and a selective sensation perception task was performed to achieve two types of selections similar to motor imagery Brain-Computer Interface. The proposed system was based on event-related desynchronization/synchronization (ERD/ERS), which had a correlation with processing of afferent inflow in human somatosensory system, and attentional effect which modulated the ERD/ERS. The experiments were carried out on nine subjects (without experience in selective sensation), and six of them showed a discrimination accuracy above 80%, three of them above 95%. Comparative experiments with motor imagery (with and without presence of stimulation) were also carried out, which further showed the feasibility of selective sensation as an alternative BCI task complementary to motor imagery. Specifically there was significant improvement () from near 65% in motor imagery (with and without presence of stimulation) to above 80% in selective sensation on some subjects. The proposed BCI modality might well cooperate with existing BCI modalities in the literature in enlarging the widespread usage of BCI system. PMID:23762253

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

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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.

Validation of a psychophysiological waking erectile assessment (WEA) for the diagnosis of male erectile disorder

NARCIS (Netherlands)

Janssen, E.; Everaerd, W.; van Lunsen, R. H.; Oerlemans, S.

1994-01-01

The aim of the present study was to evaluate a psychophysiological waking erectile assessment (WEA). WEA was designed to elicit penile responses using visual and vibrotactile stimuli and cognitive tasks (distraction and monitoring of erections). One hundred consecutive patients with erectile

Vibrotactile Feedbacks System for Assisting the Physically Impaired Persons for Easy Navigation

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Safa, M.; Geetha, G.; Elakkiya, U.; Saranya, D.

2018-04-01

NAYAN architecture is for a visually impaired person to help for navigation. As well known, all visually impaired people desperately requires special requirements even to access services like the public transportation. This prototype system is a portable device; it is so easy to carry in any conduction to travel through a familiar and unfamiliar environment. The system consists of GPS receiver and it can get NEMA data through the satellite and it is provided to user's Smartphone through Arduino board. This application uses two vibrotactile feedbacks that will be placed in the left and right shoulder for vibration feedback, which gives information about the current location. The ultrasonic sensor is used for obstacle detection which is found in front of the visually impaired person. The Bluetooth modules connected with Arduino board is to send information to the user's mobile phone which it receives from GPS.

Tactile cueing effects on performance in simulated aerial combat with high acceleration

NARCIS (Netherlands)

Erp, J.B.F. van; Eriksson, L.; Levin, B.; Carlander, O.; Veltman, J.A.; Vos, W.K.

2007-01-01

Introduction: Recent evidence indicates that vibrotactile displays can potentially reduce the risk of sensory and cognitive overload. Before these displays can be introduced in super agile aircraft, it must be ascertained that vibratory stimuli can be sensed and interpreted by pilots subjected to

System to induce and measure embodiment of an artificial hand with programmable convergent visual and tactile stimuli.

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Benz, Heather L; Sieff, Talia R; Alborz, Mahsa; Kontson, Kimberly; Kilpatrick, Elizabeth; Civillico, Eugene F

2016-08-01

The sense of prosthesis embodiment, or the feeling that the device has been incorporated into a user's body image, may be enhanced by emerging technology such as invasive electrical stimulation for sensory feedback. In turn, prosthesis embodiment may be linked to increased prosthesis use and improved functional outcomes. We describe the development of a tool to assay artificial hand embodiment in a quantitative way in people with intact limbs, and characterize its operation. The system delivers temporally coordinated visual and tactile stimuli at a programmable latency while recording limb temperature. When programmed to deliver visual and tactile stimuli synchronously, recorded latency between the two was 33 ± 24 ms in the final pilot subject. This system enables standardized assays of the conditions necessary for prosthesis embodiment.

A delivery device for presentation of tactile stimuli during functional magnetic resonance imaging.

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Dykes, Robert W; Miqueé, Aline; Xerri, Christian; Zennou-Azogui, Yoh'i; Rainville, Constant; Dumoulin, André; Marineau, Daniel

2007-01-30

We describe a novel stimulus delivery system designed to present tactile stimuli to a subject in the tunnel of a magnetic resonance imaging (MRI) system. Using energy from an air-driven piston to turn a wheel, the device advances a conveyor belt with a pre-determined sequence of stimuli that differ in their spatial features into the tunnel of the MRI. The positioning of one or several stimulus objects in a window near the subject's hand is controlled by a photoelectric device that detects periodic openings in the conveyor belt. Using this electric signal to position each presentation avoids cumulative positioning errors and provides a signal related to the progression of the experiment. We used a series of shapes that differed in their spatial features but the device could carry stimuli with a diversity of shapes and textures. This flexibility allows the experimenter to design a wide variety of psychophysical experiments in the haptic world and possibly to compare and contrast these stimuli with the cognitive treatment of similar stimuli delivered to the other senses. Appropriate experimental design allows separation of motor, sensory and memory storage phases of mental processes.

A comparison of different informative vibrotactile forward collision warnings: does the warning need to be linked to the collision event?

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Rob Gray

Full Text Available Recent research demonstrates that auditory and vibrotactile forward collision warnings presenting a motion signal (e.g., looming or apparent motion across the body surface can facilitate speeded braking reaction times (BRTs. The purpose of the present study was to expand on this work by directly comparing warning signals in which the motion conveyed was constant across all collision events with signals in which the speed of motion was dependent on the closing velocity (CV. Two experiments were conducted using a simulated car-following task and BRTs were measured. In Experiment 1, increasing intensity (looming vibrotactile signals were presented from a single tactor attached to the driver's waist. When the increase in intensity was CV-linked, BRTs were significantly faster as compared to a no-warning condition, however, they were not significantly different from constant intensity and CV-independent looming warnings. In Experiment 2, a vertical array of three tactors was used to create motion either towards (upwards or away (downwards from the driver's head. When the warning signal presented upwards motion that was CV-linked, BRTs were significantly faster than all other warning types. Downwards warnings led to a significantly higher number of brake activations in false alarm situations as compared to upwards moving warnings. The effectiveness of dynamic tactile collision warnings would therefore appear to depend on both the link between the warning and collision event and on the directionality of the warning signal.

The Vibe of Skating; Design and Testing of a Vibro-Tactile Feedback System

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Arjen J. Jansen

2018-03-01

Full Text Available Providing athletes with real-time feedback on their performance is becoming common in many sports, also in speed skating. This research-by-design project aims at finding a tool that allows the speed skater to get real-time feedback on his performance. Speed skaters often mention a so-called “good feeling” when skating behind a better skater. It is the feeling nearly every speed skater is after when skating alone; skate with less power while maintaining the same speed and feeling of ease. A longer push-off phase at a constant cadence has proven to contribute to this ideal situation but is hard for the coach alone to influence this. Therefore, a system was designed that measures the skating cadence and challenges the skater to change his skating stroke by means of vibro-tactile feedback. Four subjects have tested the feedback system. From this test, we concluded that the system provides meaningful feedback towards changing the skating cycle.

Effect of stimuli, transducers and gender on acoustic change complex

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Hemanth N. Shetty

2012-08-01

Full Text Available The objective of this study was to investigate the effect of stimuli, transducers and gender on the latency and amplitude of acoustic change complex (ACC. ACC is a multiple overlapping P1-N1-P2 complex reflecting acoustic changes across the entire stimulus. Fifteen males and 15 females, in the age range of 18 to 25 (mean=21.67 years, having normal hearing participated in the study. The ACC was recorded using the vertical montage. The naturally produced stimuli /sa/ and /si/ were presented through the insert earphone/loud speaker to record the ACC. The ACC obtained from different stimuli presented through different transducers from male/female participants were analyzed using mixed analysis of variance. Dependent t-test and independent t-test were performed when indicated. There was a significant difference in latency of 2N1 at the transition, with latency for /sa/ being earlier; but not at the onset portions of ACC. There was no significant difference in amplitude of ACC between the stimuli. Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli. Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant. ACC provides important insight in detecting the subtle spectral changes in each stimulus. Among the transducers, no difference in ACC was noted as the spectra of stimuli delivered were within the frequency response of the transducers. The earlier 2N1 latency and larger N1 and 2P2 amplitudes noticed in female participants could be due to smaller head circumference. The findings of this study will be useful in determining the capacity of the auditory pathway in detecting subtle spectral changes in the stimulus at the level of the auditory cortex.

Sistema de Alerta al Conductor Basado en Realimentación Vibro-Táctil

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Emanuel Slawiñski

2015-01-01

Full Text Available Resumen: Este trabajo propone el diseño y desarrollo de un sistema de alerta al conductor basado en la realimentación de estimulos vibro- táctiles de fuerza con el objetivo de prevenir accidentes de tránsito. El sistema posee dos agarres vibro-tactiles, los cuales se pueden montar facilmente sobre cualquier tipo de vehículo, y un sistema electrónico basado en un sistema de localización y comunicación inalámbrica entre vehículos, que permite calcular en línea una señal de alerta vibro-táctil para avisar al conductor de una posible situación de peligro en los proximos segundos. Un modelo focalizado en factores humanos es propuesto y utilizado para justificar el uso adecuado de estímulos artificiales. Además se describen, el hardware, la comunicación entre vehículos y software embebido. Finalmente, el sistema es probado en un simulador 3D de carrera de código abierto y también utilizando dos vehículos comunes. Abstract: This paper proposes the design and build of a driver warning system, based on vibro-tactile feedback for preventing accidents through the generation of tactile stimuli. The system has two vibro-tactile grips devices which are easily mounted on the steering wheel of any vehicle and an electronic system based on location sensing as well as inter-vehicles communication, from which a risk level is computed on line in order to warn the driver about dangerous situations and risk zones. A model focalized on human factors is proposed and it is employed to justify the advantages of using artificial stimuli. Besides, the hardware, communication between vehicles and embedded software, are described too. Finally, experiences using the device in a racing car simulator and tests using two ordinary cars are shown. Palabras clave: seguridad, sensores e instrumentos virtuales, automoción, estímulos táctiles de fuerza, prevención de accidentes, Keywords: Safety, sensors and virtual instrument, automotive, vibro-tactile

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

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Jun Yin

2016-07-01

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

Delineation of somatosensory finger areas using vibrotactile stimulation, an ECoG study.

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Wahnoun, Rémy; Benson, Michelle; Helms-Tillery, Stephen; Adelson, P David

2015-10-01

In surgical planning for epileptic focus resection, functional mapping of eloquent cortex is attained through direct electrical stimulation of the brain. This procedure is uncomfortable, can trigger seizures or nausea, and relies on subjective evaluation. We hypothesize that a method combining vibrotactile stimulation and statistical clustering may provide improved somatosensory mapping. Seven pediatric candidates for surgical resection underwent a task in which their fingers were independently stimulated using a custom designed finger pad, during electrocorticographic monitoring. A cluster-based statistical analysis was then performed to localize the elicited activity on the recording grids. Mid-Gamma clusters (65-115 Hz) arose in areas consistent with anatomical predictions as well as clinical findings, with five subjects presenting a somatotopic organization of the fingers. This process allowed us to delineate finger representation even in patients who were sleeping, with strong interictal activity, or when electrical stimulation did not successfully locate eloquent areas. We suggest that this scheme, relying on the endogenous neural response rather than exogenous electrical activation, could eventually be extended to map other sensory areas and provide a faster and more objective map to better anticipate outcomes of surgical resection.

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

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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

The design of a device for hearer and feeler differentiation, part A. [speech modulated hearing device

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Creecy, R.

1974-01-01

A speech modulated white noise device is reported that gives the rhythmic characteristics of a speech signal for intelligible reception by deaf persons. The signal is composed of random amplitudes and frequencies as modulated by the speech envelope characteristics of rhythm and stress. Time intensity parameters of speech are conveyed through the vibro-tactile sensation stimuli.

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.

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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.

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

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

2017-09-01

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

Cortical responses from adults and infants to complex visual stimuli.

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Schulman-Galambos, C; Galambos, R

1978-10-01

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

Perceiving, imaging, and preferring physiognomic stimuli.

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Lindauer, M S

1986-01-01

Physiognomic color responses in perception, imagery, and affect were investigated. Maluma and taketa, nonsense stimuli defined by many investigators as physiognomic, were utilized as prototypical physiognomic stimuli, along with eight other stimuli of various sorts. In Experiment 1, 22 subjects matched the colors of the stimuli; in Experiment 2, 27 subjects reported their imagery to the stimuli; and in Experiment 3, 16 subjects gave their color preferences for the stimuli. The Munsell sets of colors were employed throughout. Significant differences between the physiognomic and other stimuli were found on the brightness and saturation of color matches, images, and preferences. Other differences (e.g., the latency of color images) were also present. Distinctions were also noted between the two physiognomic stimuli. These results support the priority of innate and perceptual processes in physiognomy over those of learning and memory, although some ambiguities still remain.

Stimuli-Responsive Polymeric Nanoparticles.

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Liu, Xiaolin; Yang, Ying; Urban, Marek W

2017-07-01

There is increasing evidence that stimuli-responsive nanomaterials have become significantly critical components of modern materials design and technological developments. Recent advances in synthesis and fabrication of stimuli-responsive polymeric nanoparticles with built-in stimuli-responsive components (Part A) and surface modifications of functional nanoparticles that facilitate responsiveness (Part B) are outlined here. The synthesis and construction of stimuli-responsive spherical, core-shell, concentric, hollow, Janus, gibbous/inverse gibbous, and cocklebur morphologies are discussed in Part A, with the focus on shape, color, or size changes resulting from external stimuli. Although inorganic/metallic nanoparticles exhibit many useful properties, including thermal or electrical conductivity, catalytic activity, or magnetic properties, their assemblies and formation of higher order constructs are often enhanced by surface modifications. Section B focuses on selected surface reactions that lead to responsiveness achieved by decorating nanoparticles with stimuli-responsive polymers. Although grafting-to and grafting-from dominate these synthetic efforts, there are opportunities for developing novel synthetic approaches facilitating controllable recognition, signaling, or sequential responses. Many nanotechnologies utilize a combination of organic and inorganic phases to produce ceramic or metallic nanoparticles. One can envision the development of new properties by combining inorganic (metals, metal oxides) and organic (polymer) phases into one nanoparticle designated as "ceramers" (inorganics) and "metamers" (metallic). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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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.

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

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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.

Emotional stimuli and motor conversion disorder

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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,

A behavioral approach to shared mapping of peripersonal space between oneself and others.

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Teramoto, Wataru

2018-04-03

Recent physiological studies have showed that some visuotactile brain areas respond to other's peripersonal spaces (PPS) as they would their own. This study investigates this PPS remapping phenomenon in terms of human behavior. Participants placed their left hands on a tabletop screen where visual stimuli were projected. A vibrotactile stimulator was attached to the tip of their index finger. While a white disk approached or receded from the hand in the participant's near or far space, the participant was instructed to quickly detect a target (vibrotactile stimulation, change in the moving disk's color or both). When performing this task alone, the participants exhibited shorter detection times when the disk approached the hand in their near space. In contrast, when performing the task with a partner across the table, the participants exhibited shorter detection times both when the disk approached their own hand in their near space and when it approached the partner's hand in the partner's near space but the participants' far space. This phenomenon was also observed when the body parts from which the visual stimuli approached/receded differed between the participant and partner. These results suggest that humans can share PPS representations and/or body-derived attention/arousal mechanisms with others.

Emotional Stimuli and Motor Conversion Disorder

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

2010-01-01

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

Poly(acrylic acid)-block-poly(vinyl alcohol) anchored maghemite nanoparticles designed for multi-stimuli triggered drug release

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Liu, Ji; Detrembleur, Christophe; Debuigne, Antoine; de Pauw-Gillet, Marie-Claire; Mornet, Stéphane; Vander Elst, Luce; Laurent, Sophie; Labrugère, Christine; Duguet, Etienne; Jérôme, Christine

2013-11-01

Original core/corona nanoparticles composed of a maghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene blue (MB), a cationic model drug. The triggered release of MB was studied under various stimuli such as pH, ionic strength and temperature. Local heating generated under alternating magnetic field (AMF) application was studied, and remotely AMF-triggered release was also confirmed, while a mild heating-up of the release medium was observed. Furthermore, their potential application as magnetic resonance imaging (MRI) contrast agents was explored via relaxivity measurements and acquisition of T2-weighted images. Preliminary studies on the cytotoxicity against mouse fibroblast-like L929 cell line and also their cellular uptake within human melanoma MEL-5 cell line were carried out. In conclusion, this kind of stimuli-responsive nanoparticles appears to be promising carriers for delivering drugs to some tumour sites or into cellular compartments with an acidic environment.Original core/corona nanoparticles composed of a maghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene

Rhythmic Haptic Stimuli Improve Short-Term Attention.

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Zhang, Shusheng; Wang, Dangxiao; Afzal, Naqash; Zhang, Yuru; Wu, Ruilin

2016-01-01

Brainwave entrainment using rhythmic visual and/or auditory stimulation has shown its efficacy in modulating neural activities and cognitive ability. In the presented study, we aim to investigate whether rhythmic haptic stimulation could enhance short-term attention. An experiment with sensorimotor rhythm (SMR) increasing protocol was performed in which participants were presented sinusoidal vibrotactile stimulus of 15 Hz on their palm. Test of Variables of Attention (T.O.V.A.) was performed before and after the stimulating session. Electroencephalograph (EEG) was recorded across the stimulating session and the two attention test sessions. SMR band power manifested a significant increase after stimulation. Results of T.O.V.A. tests indicated an improvement in the attention of participants who had received the stimulation compared to the control group who had not received the stimulation. The D prime score of T.O.V.A. reveals that participants performed better in perceptual sensitivity and sustaining attention level compared to their baseline performance before the stimulating session. These findings highlight the potential value of using haptics-based brainwave entrainment for cognitive training.

Dual and multi-stimuli responsive polymeric nanoparticles for programmed site-specific drug delivery.

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Cheng, Ru; Meng, Fenghua; Deng, Chao; Klok, Harm-Anton; Zhong, Zhiyuan

2013-05-01

In the past decades, polymeric nanoparticles have emerged as a most promising and viable technology platform for targeted and controlled drug delivery. As vehicles, ideal nanoparticles are obliged to possess high drug loading levels, deliver drug to the specific pathological site and/or target cells without drug leakage on the way, while rapidly unload drug at the site of action. To this end, various "intelligent" polymeric nanoparticles that release drugs in response to an internal or external stimulus such as pH, redox, temperature, magnetic and light have been actively pursued. These stimuli-responsive nanoparticles have demonstrated, though to varying degrees, improved in vitro and/or in vivo drug release profiles. In an effort to further improve drug release performances, novel dual and multi-stimuli responsive polymeric nanoparticles that respond to a combination of two or more signals such as pH/temperature, pH/redox, pH/magnetic field, temperature/reduction, double pH, pH and diols, temperature/magnetic field, temperature/enzyme, temperature/pH/redox, temperature/pH/magnetic, pH/redox/magnetic, temperature/redox/guest molecules, and temperature/pH/guest molecules have recently been developed. Notably, these combined responses take place either simultaneously at the pathological site or in a sequential manner from nanoparticle preparation, nanoparticle transporting pathways, to cellular compartments. These dual and multi-stimuli responsive polymeric nanoparticles have shown unprecedented control over drug delivery and release leading to superior in vitro and/or in vivo anti-cancer efficacy. With programmed site-specific drug delivery feature, dual and multi-stimuli responsive nanoparticulate drug formulations have tremendous potential for targeted cancer therapy. In this review paper, we highlight the recent exciting developments in dual and multi-stimuli responsive polymeric nanoparticles for precision drug delivery applications, with a particular focus

A microfluidic device to study neuronal and motor responses to acute chemical stimuli in zebrafish.

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Candelier, Raphaël; Murmu, Meena Sriti; Romano, Sebastián Alejo; Jouary, Adrien; Debrégeas, Georges; Sumbre, Germán

2015-07-21

Zebrafish larva is a unique model for whole-brain functional imaging and to study sensory-motor integration in the vertebrate brain. To take full advantage of this system, one needs to design sensory environments that can mimic the complex spatiotemporal stimulus patterns experienced by the animal in natural conditions. We report on a novel open-ended microfluidic device that delivers pulses of chemical stimuli to agarose-restrained larvae with near-millisecond switching rate and unprecedented spatial and concentration accuracy and reproducibility. In combination with two-photon calcium imaging and recordings of tail movements, we found that stimuli of opposite hedonic values induced different circuit activity patterns. Moreover, by precisely controlling the duration of the stimulus (50-500 ms), we found that the probability of generating a gustatory-induced behavior is encoded by the number of neurons activated. This device may open new ways to dissect the neural-circuit principles underlying chemosensory perception.

Binocular Combination of Second-Order Stimuli

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Zhou, Jiawei; Liu, Rong; Zhou, Yifeng; Hess, Robert F.

2014-01-01

Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated) and second-order (contrast modulated) stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on the interocular signal ratio as has been previously shown for their first order counterparts; the interocular signal ratios when the two eyes were balanced was close to 1 in both first- and second-order phase combinations. However, second-order combination is more linear than previously found for first-order combination. Furthermore, binocular combination of second-order stimuli was similar regardless of whether the carriers in the two eyes were correlated, anti-correlated, or uncorrelated. This suggests that, in normal adults, the binocular phase combination of second-order stimuli occurs after the monocular extracting of the second-order modulations. The sensory balance associated with this second-order combination can be obtained from binocular phase combination measurements. PMID:24404180

A review of stimuli-responsive polymers for smart textile applications

International Nuclear Information System (INIS)

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

2012-01-01

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. (topical review)

Can persons with dementia be engaged with stimuli?

Science.gov (United States)

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

2010-04-01

To determine which stimuli are 1) most engaging 2) most often refused by nursing home residents with dementia, and 3) most appropriate for persons who are more difficult to engage with stimuli. Participants were 193 residents of seven Maryland nursing homes. All participants had a diagnosis of dementia. Stimulus engagement was assessed by the Observational Measure of Engagement. The most engaging stimuli were one-on-one socializing with a research assistant, a real baby, personalized stimuli based on the person's self-identity, a lifelike doll, a respite video, and envelopes to stamp. Refusal of stimuli was higher among those with higher levels of cognitive function and related to the stimulus' social appropriateness. Women showed more attention and had more positive attitudes for live social stimuli, simulated social stimuli, and artistic tasks than did men. Persons with comparatively higher levels of cognitive functioning were more likely to be engaged in manipulative and work tasks, whereas those with low levels of cognitive functioning spent relatively more time responding to social stimuli. The most effective stimuli did not differ for those most likely to be engaged and those least likely to be engaged. Nursing homes should consider both having engagement stimuli readily available to residents with dementia, and implementing a socialization schedule so that residents receive one-on-one interaction. Understanding the relationship among type of stimulus, cognitive function, and acceptance, attention, and attitude toward the stimuli can enable caregivers to maximize the desired benefit for persons with dementia.

Effects of aging on vibration detection thresholds at various body regions

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Walsh Natalie

2003-02-01

Full Text Available Abstract Background The ability to detect sinusoidal vibrations on the skin surface is dependent on the activation of two classes of receptors. The density of such receptors varies across the skin surface and is a factor in determining the sensory acuity of each skin area. However, the acuity of many sensory systems is known to deteriorate with advancing age. The aim of this study was to determine if vibrotactile sensibility of several skin surfaces deteriorated equally with advancing age. Methods Vibration detection thresholds for two frequencies of vibration (30 Hz and 200 Hz were determined using a method of limits protocol, in two groups of healthy adults, one group aged 17 to 27 years and the other aged 55 to 90 years. Sinusoidal vibrations were generated by a computer and delivered to the skin surface via the probe (diameter = 2 mm of a mechanical vibrator. Four skin sites (palmar surface of the tip of the middle finger, volar surface of the forearm, lateral aspect of the shoulder, cheek just caudal to the zygoma were tested. Results The fingertip was the most sensitive site for vibrotactile detection at both frequencies in a substantial majority of subjects. The older group of subjects showed significantly higher detection thresholds for both frequencies at all sites, except the fingertip, when compared to young subjects. Conclusion The study confirms the deterioration of vibrotactile acuity at several skin sites previously reported in the literature. However, there appears to be no significant reduction in vibrotactile detection at the fingertips in older subjects. This may reflect the high receptor density of this area, or the functional importance of vibrotactile sensibility of the fingertips or some combination of both of these factors.

SPET monitoring of perfusion changes in auditory cortex following mono- and multi-frequency stimuli

Energy Technology Data Exchange (ETDEWEB)

De Rossi, G. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Paludetti, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Di Nardo, W. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Calcagni, M.L. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Di Giuda, D. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Almadori, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Galli, J. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy)

1996-08-01

In order to assess the relationship between auditory cortex perfusion and the frequency of acoustic stimuli, twenty normally-hearing subjects underwent cerebral SPET. In 10 patients a multi-frequency stimulus (250-4000 Hz at 40 dB SL) was delivered, while 10 subjects were stimulated with a 500 Hz pure tone at 40 dB SL. The prestimulation SPET was subtracted from poststimulation study and auditory cortex activation was expressed as percent increments. Contralateral cortex was the most active area with multifrequency and monofrequency stimuli as well. A clear demonstration of a tonotopic distribution of acoustic stimuli in the auditory cortex was achieved. In addition, the accessory role played by homolateral accoustic areas was confirmed. The results of the present research support the hypothesis that brain SPET may be useful to obtain semiquantitative reliable information on low frequency auditory level in profoundly deaf patients. This may be achieved comparing the extension of the cortical areas activated by high-intensity multifrequency stimuli. (orig.) [Deutsch] Zur Aufklaerung der Beziehung von regionaler Perfusion des auditorischen Kortex und Frequenz des akustischen Stimulus wurden 20 Normalpatienten mit Hilfe von Hirn-SPECT untersucht. Bei je 10 Patienten wurde ein Multifrequenzstimulus (250-2000 Hz bei 60 dB) bzw. ein Monofrequenzstimulus (500 Hz bei 60 dB) verwendet. Die vor der Stimulation akquirierten SPECT-Daten wurden jeweils von den nach der Stimulation akquirierten SPECT-Daten abgezogen und die aditorische Kortexaktivation als prozentuale Steigerung ausgedrueckt. Der kontralaterale Kortex war das am staerksten aktivierte Areal sowohl bei der Multifrequenz- als auch bei der Monofrequenzstimulation. Es konnte eine klare tonotopische Verteilung der akustischen Stimuli im auditorischen Koretx demonstriert werden. Zusaetzlich konnte die akzessorische Rolle des homolateralen akustischen Kortex bestaetigt werden. Die Ergebnisse dieser Studie unterstuetzen

Developing Affective Mental Imagery Stimuli with Multidimensional Scaling

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Matthew J. Facciani

2015-06-01

Full Text Available The goal of this paper is to provide an example of how multidimensional scaling (MDS can be used for stimuli development. The study described in this paper illustrates this process by developing affective mental imagery stimuli using the circumplex model of affect as a guide. The circumplex model of affect argues that all emotions can be described in terms of two underlying primary dimensions: valence and arousal (Russel, 1980. We used MDS to determine if affective mental imagery stimuli obtained from verbal prompts could be separated by arousal and valence to create four distinct categories (high –positive, low-positive, high-negative, and low-negative as seen in other stimuli. 60 students from the University of South Carolina participated in the first experiment to evaluate three sets of stimuli. After being analyzed using MDS, selected stimuli were then assessed again in a second experiment to validate their robust valence and arousal distinctions. The second experiment was conducted with 34 subjects to validate 40 of the best stimuli from experiment 1. It was found that mental imagery stimuli can produce a reliable affective response for the dimensions of valence and arousal and that MDS can be an effective tool for stimuli development.

Equal vibrotactile sense thresholds of the fingers and its diagnostic significance for hand-arm vibration syndrome.

Science.gov (United States)

Cheng, H; Zhang, X C; Duan, L; Ma, Y; Wang, J X

1995-01-01

The vibrotactile sense thresholds (VSTs) of the middle fingers of 60 healthy persons and 97 patients with Hand-Arm Vibration Syndrome (HAVS) or subclinical HAVS were measured quantitatively. Intermittent vibratory irritations were adopted, with vibration stimulus frequencies at 8, 16, 31.5, 63, 125, 250, and 500 Hz. The equal VST contours of the fingers were mapped. Results showed that the VSTs of the normal group were not correlated with sex or handedness. From 8 Hz to 250 Hz the equal VST contours of the normal group were relatively flat; at more than 250 Hz the contours began an abrupt ascent. The VST values had a logarithmic rising tendency with the increasing age of subjects. In the equal VST contours the frequency of the most sensitive threshold value was 125 Hz in the normal group and 8 Hz in the HAVS group. The patients' VST values were higher than that of the healthy persons. The vibrotactilegram showed that the VST values of the patient groups first shifted at high frequencies and VST loss displayed a "V"-type hollow at 125 Hz and 250 Hz. The quantitative test method of VST was a valuable auxiliary detection method for HAVS. The "V"-type hollow of VST was an early clinical manifestation of HAVS.

Virtual reality stimuli for force platform posturography.

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Tossavainen, Timo; Juhola, Martti; Ilmari, Pyykö; Aalto, Heikki; Toppila, Esko

2002-01-01

People relying much on vision in the control of posture are known to have an elevated risk of falling. Dependence on visual control is an important parameter in the diagnosis of balance disorders. We have previously shown that virtual reality methods can be used to produce visual stimuli that affect balance, but suitable stimuli need to be found. In this study the effect of six different virtual reality stimuli on the balance of 22 healthy test subjects was evaluated using force platform posturography. According to the tests two of the stimuli have a significant effect on balance.

Effects of long-term balance training with vibrotactile sensory augmentation among community-dwelling healthy older adults: a randomized preliminary study.

Science.gov (United States)

Bao, Tian; Carender, Wendy J; Kinnaird, Catherine; Barone, Vincent J; Peethambaran, Geeta; Whitney, Susan L; Kabeto, Mohammed; Seidler, Rachael D; Sienko, Kathleen H

2018-01-18

Sensory augmentation has been shown to improve postural stability during real-time balance applications. Limited long-term controlled studies have examined retention of balance improvements in healthy older adults after training with sensory augmentation has ceased. This pilot study aimed to assess the efficacy of long-term balance training with and without sensory augmentation among community-dwelling healthy older adults. Twelve participants (four males, eight females; 75.6 ± 4.9 yrs) were randomly assigned to the experimental group (n = 6) or control group (n = 6). Participants trained in their homes for eight weeks, completing three 45-min exercise sessions per week using smart phone balance trainers that provided written, graphic, and video guidance, and monitored trunk sway. During each session, participants performed six repetitions of six exercises selected from five categories (static standing, compliant surface standing, weight shifting, modified center of gravity, and gait). The experimental group received vibrotactile sensory augmentation for four of the six repetitions per exercise via the smart phone balance trainers, while the control group performed exercises without sensory augmentation. The smart phone balance trainers sent exercise performance data to a physical therapist, who recommended exercises on a weekly basis. Balance performance was assessed using a battery of clinical balance tests (Activity Balance Confidence Scale, Sensory Organization Test, Mini Balance Evaluation Systems Test, Five Times Sit to Stand Test, Four Square Step Test, Functional Reach Test, Gait Speed Test, Timed Up and Go, and Timed Up and Go with Cognitive Task) before training, after four weeks of training, and after eight weeks of training. Participants in the experimental group were able to use vibrotactile sensory augmentation independently in their homes. After training, the experimental group had significantly greater improvements in Sensory

Instructed fear stimuli bias visual attention

NARCIS (Netherlands)

Deltomme, Berre; Mertens, G.; Tibboel, Helen; Braem, Senne

We investigated whether stimuli merely instructed to be fear-relevant can bias visual attention, even when the fear relation was never experienced before. Participants performed a dot-probe task with pictures of naturally fear-relevant (snake or spider) or -irrelevant (bird or butterfly) stimuli.

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.

Stimuli-Regulated Smart Polymeric Systems for Gene Therapy

Directory of Open Access Journals (Sweden)

Ansuja Pulickal Mathew

2017-04-01

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

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.

Effects of Unaugmented Periphery and Vibrotactile Feedback on Proxemics with Virtual Humans in AR.

Science.gov (United States)

Lee, Myungho; Bruder, Gerd; Hollerer, Tobias; Welch, Greg

2018-04-01

In this paper, we investigate factors and issues related to human locomotion behavior and proxemics in the presence of a real or virtual human in augmented reality (AR). First, we discuss a unique issue with current-state optical see-through head-mounted displays, namely the mismatch between a small augmented visual field and a large unaugmented periphery, and its potential impact on locomotion behavior in close proximity of virtual content. We discuss a potential simple solution based on restricting the field of view to the central region, and we present the results of a controlled human-subject study. The study results show objective benefits for this approach in producing behaviors that more closely match those that occur when seeing a real human, but also some drawbacks in overall acceptance of the restricted field of view. Second, we discuss the limited multimodal feedback provided by virtual humans in AR, present a potential improvement based on vibrotactile feedback induced via the floor to compensate for the limited augmented visual field, and report results showing that benefits of such vibrations are less visible in objective locomotion behavior than in subjective estimates of co-presence. Third, we investigate and document significant differences in the effects that real and virtual humans have on locomotion behavior in AR with respect to clearance distances, walking speed, and head motions. We discuss potential explanations for these effects related to social expectations, and analyze effects of different types of behaviors including idle standing, jumping, and walking that such real or virtual humans may exhibit in the presence of an observer.

Steady-state evoked potentials to study the processing of tactile and nociceptive somatosensory input in the human brain.

Science.gov (United States)

Colon, E; Legrain, V; Mouraux, A

2012-10-01

The periodic presentation of a sensory stimulus induces, at certain frequencies of stimulation, a sustained electroencephalographic response of corresponding frequency, known as steady-state evoked potentials (SS-EP). In visual, auditory and vibrotactile modalities, studies have shown that SS-EP reflect mainly activity originating from early, modality-specific sensory cortices. Furthermore, it has been shown that SS-EP have several advantages over the recording of transient event-related brain potentials (ERP), such as a high signal-to-noise ratio, a shorter time to obtain reliable signals, and the capacity to frequency-tag the cortical activity elicited by concurrently presented sensory stimuli. Recently, we showed that SS-EP can be elicited by the selective activation of skin nociceptors and that nociceptive SS-EP reflect the activity of a population of neurons that is spatially distinct from the somatotopically-organized population of neurons underlying vibrotactile SS-EP. Hence, the recording of SS-EP offers a unique opportunity to study the cortical representation of nociception and touch in humans, and to explore their potential crossmodal interactions. Here, (1) we review available methods to achieve the rapid periodic stimulation of somatosensory afferents required to elicit SS-EP, (2) review previous studies that have characterized vibrotactile and nociceptive SS-EP, (3) discuss the nature of the recorded signals and their relationship with transient event-related potentials and (4) outline future perspectives and potential clinical applications of this technique. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Low dose intranasal oxytocin delivered with Breath Powered device dampens amygdala response to emotional stimuli: A peripheral effect-controlled within-subjects randomized dose-response fMRI trial.

Science.gov (United States)

Quintana, Daniel S; Westlye, Lars T; Alnæs, Dag; Rustan, Øyvind G; Kaufmann, Tobias; Smerud, Knut T; Mahmoud, Ramy A; Djupesland, Per G; Andreassen, Ole A

2016-07-01

It is unclear if and how exogenous oxytocin (OT) reaches the brain to improve social behavior and cognition and what is the optimal dose for OT response. To better understand the delivery routes of intranasal OT administration to the brain and the dose-response, we compared amygdala response to facial stimuli by means of functional magnetic resonance imaging (fMRI) in four treatment conditions, including two different doses of intranasal OT using a novel Breath Powered device, intravenous (IV) OT, which provided similar concentrations of blood plasma OT, and placebo. We adopted a randomized, double-blind, double-dummy, crossover design, with 16 healthy male adults administering a single-dose of these four treatments. We observed a treatment effect on right amygdala activation during the processing of angry and happy face stimuli, with pairwise comparisons revealing reduced activation after the 8IU low dose intranasal treatment compared to placebo. These data suggest the dampening of amygdala activity in response to emotional stimuli occurs via direct intranasal delivery pathways rather than across the blood-brain barrier via systemically circulating OT. This trial is registered at the U.S. National Institutes of Health clinical trial registry (www.clinicaltrials.gov; NCT01983514) and as EudraCT no. 2013-001608-12. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Steady-state VEP responses to uncomfortable stimuli.

Science.gov (United States)

O'Hare, Louise

2017-02-01

Periodic stimuli, such as op-art, can evoke a range of aversive sensations included in the term visual discomfort. Illusory motion effects are elicited by fixational eye movements, but the cortex might also contribute to effects of discomfort. To investigate this possibility, steady-state visually evoked responses (SSVEPs) to contrast-matched op-art-based stimuli were measured at the same time as discomfort judgements. On average, discomfort reduced with increasing spatial frequency of the pattern. In contrast, the peak amplitude of the SSVEP response was around the midrange spatial frequencies. Like the discomfort judgements, SSVEP responses to the highest spatial frequencies were lowest amplitude, but the relationship breaks down between discomfort and SSVEP for the lower spatial frequency stimuli. This was not explicable by gross eye movements as measured using the facial electrodes. There was a weak relationship between the peak SSVEP responses and discomfort judgements for some stimuli, suggesting that discomfort can be explained in part by electrophysiological responses measured at the level of the cortex. However, there is a breakdown of this relationship in the case of lower spatial frequency stimuli, which remains unexplained. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Stimulus-dependent effects on tactile spatial acuity

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Tommerdahl M

2005-10-01

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

Stimuli responsive nanomaterials for controlled release applications

KAUST Repository

Li, Song; Li, Wengang; Khashab, Niveen M.

2012-01-01

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

Prior and present evidence: how prior experience interacts with present information in a perceptual decision making task.

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Muhsin Karim

Full Text Available Vibrotactile discrimination tasks have been used to examine decision making processes in the presence of perceptual uncertainty, induced by barely discernible frequency differences between paired stimuli or by the presence of embedded noise. One lesser known property of such tasks is that decisions made on a single trial may be biased by information from prior trials. An example is the time-order effect whereby the presentation order of paired stimuli may introduce differences in accuracy. Subjects perform better when the first stimulus lies between the second stimulus and the global mean of all stimuli on the judged dimension ("preferred" time-orders compared to the alternative presentation order ("nonpreferred" time-orders. This has been conceptualised as a "drift" of the first stimulus representation towards the global mean of the stimulus-set (an internal standard. We describe the influence of prior information in relation to the more traditionally studied factors of interest in a classic discrimination task.Sixty subjects performed a vibrotactile discrimination task with different levels of uncertainty parametrically induced by increasing task difficulty, aperiodic stimulus noise, and changing the task instructions whilst maintaining identical stimulus properties (the "context".The time-order effect had a greater influence on task performance than two of the explicit factors-task difficulty and noise-but not context. The influence of prior information increased with the distance of the first stimulus from the global mean, suggesting that the "drift" velocity of the first stimulus towards the global mean representation was greater for these trials.Awareness of the time-order effect and prior information in general is essential when studying perceptual decision making tasks. Implicit mechanisms may have a greater influence than the explicit factors under study. It also affords valuable insights into basic mechanisms of information

Protein-surface interactions on stimuli-responsive polymeric biomaterials.

Science.gov (United States)

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

2016-03-04

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

Emotion attribution to basic parametric static and dynamic stimuli

NARCIS (Netherlands)

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

2009-01-01

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

Effects of Auditory Stimuli on Visual Velocity Perception

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Michiaki Shibata

2011-10-01

Full Text Available We investigated the effects of auditory stimuli on the perceived velocity of a moving visual stimulus. Previous studies have reported that the duration of visual events is perceived as being longer for events filled with auditory stimuli than for events not filled with auditory stimuli, ie, the so-called “filled-duration illusion.” In this study, we have shown that auditory stimuli also affect the perceived velocity of a moving visual stimulus. In Experiment 1, a moving comparison stimulus (4.2∼5.8 deg/s was presented together with filled (or unfilled white-noise bursts or with no sound. The standard stimulus was a moving visual stimulus (5 deg/s presented before or after the comparison stimulus. The participants had to judge which stimulus was moving faster. The results showed that the perceived velocity in the auditory-filled condition was lower than that in the auditory-unfilled and no-sound conditions. In Experiment 2, we investigated the effects of auditory stimuli on velocity adaptation. The results showed that the effects of velocity adaptation in the auditory-filled condition were weaker than those in the no-sound condition. These results indicate that auditory stimuli tend to decrease the perceived velocity of a moving visual stimulus.

Visual and auditory stimuli associated with swallowing. An fMRI study

International Nuclear Information System (INIS)

Kawai, Takeshi; Watanabe, Yutaka; Tonogi, Morio; Yamane, Gen-yuki; Abe, Shinichi; Yamada, Yoshiaki; Callan, Akiko

2009-01-01

We focused on brain areas activated by audiovisual stimuli related to swallowing motions. In this study, three kinds of stimuli related to human swallowing movement (auditory stimuli alone, visual stimuli alone, or audiovisual stimuli) were presented to the subjects, and activated brain areas were measured using functional MRI (fMRI) and analyzed. When auditory stimuli alone were presented, the supplementary motor area was activated. When visual stimuli alone were presented, the premotor and primary motor areas of the left and right hemispheres and prefrontal area of the left hemisphere were activated. When audiovisual stimuli were presented, the prefrontal and premotor areas of the left and right hemispheres were activated. Activation of Broca's area, which would have been characteristic of mirror neuron system activation on presentation of motion images, was not observed; however, activation of brain areas related to swallowing motion programming and performance was verified for auditory, visual and audiovisual stimuli related to swallowing motion. These results suggest that audiovisual stimuli related to swallowing motion could be applied to the treatment of patients with dysphagia. (author)

Perceptual Sensitivity and Response to Strong Stimuli Are Related

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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.

Stimuli-Adaptable Materials

DEFF Research Database (Denmark)

Frankær, Sarah Maria Grundahl

The work presented in this Thesis deals with the development of a stimuli-adaptable polymer material based on the UV-induced dimerisation of cinnamic acid and its derivatives. It is in the nature of an adhesive to adhere very well to its substrate and therefore problems can arise upon removal...

The effect of repeated laser stimuli to ink-marked skin on skin temperature—recommendations for a safe experimental protocol in humans

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Victoria J. Madden

2016-01-01

Full Text Available Background. Nd:YAP laser is widely used to investigate the nociceptive and pain systems, generating perpetual and laser-evoked neurophysiological responses. A major procedural concern for the use of Nd:YAP laser stimuli in experimental research is the risk of skin damage. The absorption of Nd:YAP laser stimuli is greater in darker skin, or in pale skin that has been darkened with ink, prompting some ethics boards to refuse approval to experimenters wishing to track stimulus location by marking the skin with ink. Some research questions, however, require laser stimuli to be delivered at particular locations or within particular zones, a requirement that is very difficult to achieve if marking the skin is not possible. We thoroughly searched the literature for experimental evidence and protocol recommendations for safe delivery of Nd:YAP laser stimuli over marked skin, but found nothing.Methods. We designed an experimental protocol to define safe parameters for the use of Nd:YAP laser stimuli over skin that has been marked with black dots, and used thermal imaging to assess the safety of the procedure at the forearm and the back.Results. Using thermal imaging and repeated laser stimulation to ink-marked skin, we demonstrated that skin temperature did not increase progressively across the course of the experiment, and that the small change in temperature seen at the forearm was reversed during the rest periods between blocks. Furthermore, no participant experienced skin damage due to the procedure.Conclusion. This protocol offers parameters for safe, confident and effective experimentation using repeated Nd:YAP laser on skin marked with ink, thus paving the way for investigations that depend on it.

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.

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).

Cortical processing of tactile stimuli applied in quick succession across the fingertips: temporal evolution of dipole sources revealed by magnetoencephalography.

Science.gov (United States)

Karageorgiou, Elissaios; Koutlas, Ioannis G; Alonso, Aurelio A; Leuthold, Arthur C; Lewis, Scott M; Georgopoulos, Apostolos P

2008-08-01

We used magnetoencephalography (MEG) in 10 healthy human subjects to study cortical responses to tactile stimuli applied to the fingertips of digits 2-5 of the right hand. Each stimulus lasted 50 ms and was produced by air-driven elastic membranes. Four-hundred stimuli were delivered on each finger in three temporal patterns (conditions). In the "Discrete" condition, stimuli were applied to each finger repetitively with an interstimulus interval (ISI) of 1-2 s. In the "Continuous" condition, stimuli were applied to the fingers sequentially as four-stimulus trains with zero ISI and 1-2 s intervening between trains. Finally, in the "Gap" condition, stimuli were applied as in the Continuous condition but with an ISI of 50 ms. A sensation of tactile motion across fingers (digit 2 --> digit 5) was reported by all subjects in the Continuous and Gap conditions. Cortical responses were extracted as single equivalent current dipoles over a period of 1 s following stimulus onset. In all three conditions, initial responses in left primary somatosensory cortex (SI) were observed ~20 to 50 ms after stimulus onset and were followed by additional left SI responses and bilateral responses in the secondary somatosensory cortex (SII). In addition, in the Continuous and Gap conditions, there was an activation of the precentral gyrus, the temporal aspects of which depended on the temporal relation of the administered stimuli, as follows. An ISI of 0 ms led to activation of the precentral gyrus shortly after the second stimulation, whereas an ISI of 50 ms led to activation of the precentral gyrus after the third stimulation. The current findings support results from previous studies on temporal activity patterns in SI and SII, verify the participation of the precentral gyrus during tactile motion perception and, in addition, reveal aspects of integration of sequential sensory stimulations over nonadjacent areas as well as temporal activity patterns in the postcentral and precentral

Emotional attention for erotic stimuli: Cognitive and brain mechanisms.

Science.gov (United States)

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

2016-06-01

It has long been posited that among emotional stimuli, only negative threatening information modulates early shifts of attention. However, in the last few decades there has been an increase in research showing that attention is also involuntarily oriented toward positive rewarding stimuli such as babies, food, and erotic information. Because reproduction-related stimuli have some of the largest effects among positive stimuli on emotional attention, the present work reviews recent literature and proposes that the cognitive and cerebral mechanisms underlying the involuntarily attentional orientation toward threat-related information are also sensitive to erotic information. More specifically, the recent research suggests that both types of information involuntarily orient attention due to their concern relevance and that the amygdala plays an important role in detecting concern-relevant stimuli, thereby enhancing perceptual processing and influencing emotional attentional processes. © 2015 Wiley Periodicals, Inc.

VEP Responses to Op-Art Stimuli.

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Louise O'Hare

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

VEP Responses to Op-Art Stimuli.

Science.gov (United States)

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

2015-01-01

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

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.

Stimuli-responsive nanomaterials for therapeutic protein delivery.

Science.gov (United States)

Lu, Yue; Sun, Wujin; Gu, Zhen

2014-11-28

Protein therapeutics have emerged as a significant role in treatment of a broad spectrum of diseases, including cancer, metabolic disorders and autoimmune diseases. The efficacy of protein therapeutics, however, is limited by their instability, immunogenicity and short half-life. In order to overcome these barriers, tremendous efforts have recently been made in developing controlled protein delivery systems. Stimuli-triggered release is an appealing and promising approach for protein delivery and has made protein delivery with both spatiotemporal- and dosage-controlled manners possible. This review surveys recent advances in controlled protein delivery of proteins or peptides using stimuli-responsive nanomaterials. Strategies utilizing both physiological and external stimuli are introduced and discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Translation of associative learning models into extinction reminders delivered via mobile phones during cue exposure interventions for substance use.

Science.gov (United States)

Rosenthal, M Zachary; Kutlu, Munir G

2014-09-01

Despite experimental findings and some treatment research supporting the use of cues as a means to induce and extinguish cravings, interventions using cue exposure have not been well integrated into contemporary substance abuse treatments. A primary problem with exposure-based interventions for addiction is that after learning not to use substances in the presence of addiction cues inside the clinic (i.e., extinction), stimuli in the naturalistic setting outside the clinic may continue to elicit craving, drug use, or other maladaptive conditioned responses. For exposure-based substance use interventions to be efficacious, new approaches are needed that can prevent relapse by directly generalizing learning from the therapeutic setting into naturalistic settings associated with a high risk for relapse. Basic research suggests that extinction reminders (ERs) can be paired with the context of learning new and more adaptive conditioned responses to substance abuse cues in exposure therapies for addiction. Using mobile phones and automated dialing and data collection software, ERs can be delivered in everyday high-risk settings to inhibit conditioned responses to substance-use-related stimuli. In this review, we describe how associative learning mechanisms (e.g., conditioned inhibition) can inform how ERs are conceptualized, learned, and implemented to prevent substance use when delivered via mobile phones. This approach, exposure with portable reminders of extinction, is introduced as an adjunctive intervention that uses brief automated ERs between clinic visits when individuals are in high-risk settings for drug use.

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.

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

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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.

Monitor, a vibrotactile aid for environmental perception: a field evaluation by four people with severe hearing and vision impairment.

Science.gov (United States)

Ranjbar, Parivash; Stenström, Ingeborg

2013-01-01

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.

Perceived duration of visual and tactile stimuli depends on perceived speed

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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.

Neural Processing of Emotional Musical and Nonmusical Stimuli in Depression.

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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.

Facilitation of responses by task-irrelevant complex deviant stimuli.

Science.gov (United States)

Schomaker, J; Meeter, M

2014-05-01

Novel stimuli reliably attract attention, suggesting that novelty may disrupt performance when it is task-irrelevant. However, under certain circumstances novel stimuli can also elicit a general alerting response having beneficial effects on performance. In a series of experiments we investigated whether different aspects of novelty--stimulus novelty, contextual novelty, surprise, deviance, and relative complexity--lead to distraction or facilitation. We used a version of the visual oddball paradigm in which participants responded to an occasional auditory target. Participants responded faster to this auditory target when it occurred during the presentation of novel visual stimuli than of standard stimuli, especially at SOAs of 0 and 200 ms (Experiment 1). Facilitation was absent for both infrequent simple deviants and frequent complex images (Experiment 2). However, repeated complex deviant images did facilitate responses to the auditory target at the 200 ms SOA (Experiment 3). These findings suggest that task-irrelevant deviant visual stimuli can facilitate responses to an unrelated auditory target in a short 0-200 millisecond time-window after presentation. This only occurs when the deviant stimuli are complex relative to standard stimuli. We link our findings to the novelty P3, which is generated under the same circumstances, and to the adaptive gain theory of the locus coeruleus-norepinephrine system (Aston-Jones and Cohen, 2005), which may explain the timing of the effects. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of expectation on pain assessment of lower- and higher-intensity stimuli.

Science.gov (United States)

Ružić, Valentina; Ivanec, Dragutin; Modić Stanke, Koraljka

2017-01-01

Pain modulation via expectation is a well-documented phenomenon. So far it has been shown that expectations about effectiveness of a certain treatment enhance the effectiveness of different analgesics and of drug-free pain treatments. Also, studies demonstrate that people assess same-intensity stimuli differently, depending on the experimentally induced expectations regarding the characteristics of the stimuli. Prolonged effect of expectation on pain perception and possible symmetry in conditions of lower- and higher-intensity stimuli is yet to be studied. Aim of this study is to determine the effect of expectation on the perception of pain experimentally induced by the series of higher- and lower-intensity stimuli. 192 healthy participants were assigned to four experimental groups differing by expectations regarding the intensity of painful stimuli series. Expectations of two groups were congruent with actual stimuli; one group expected and received lower-intensity stimuli and the other expected and received higher-intensity stimuli. Expectations of the remaining two groups were not congruent with actual stimuli; one group expected higher-intensity stimuli, but actually received lower-intensity stimuli while the other group expected lower-intensity stimuli, but in fact received higher-intensity ones. Each group received a series of 24 varied-intensity electrical stimuli rated by the participants on a 30° intensity scale. Expectation manipulation had statistically significant effect on pain intensity assessment. When expecting lower-intensity stimuli, the participants underestimated pain intensity and when expecting higher-intensity stimuli, they overestimated pain intensity. The effect size of expectations upon pain intensity assessment was equal for both lower- and higher-intensity stimuli. The obtained results imply that expectation manipulation can achieve the desired effect of decreasing or increasing both slight and more severe pain for a longer period of

Characterization of Ferrofluid-based Stimuli-responsive Elastomers

OpenAIRE

Sandra dePedro; Xavier Munoz-Berbel; Rosalia Rodríguez-Rodríguez; Jordi Sort; Jose Antonio Plaza; Juergen Brugger; Andreu Llobera; Victor J Cadarso

2016-01-01

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...

Encoding of emotion-paired spatial stimuli in the rodent hippocampus

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Rebecca eNalloor

2012-06-01

Full Text Available Rats can acquire the cognitive component of CS-US associations between sensory and aversive stimuli without a functional basolateral amygdala. Thus, other brain regions should support such associations. Some septal/dorsal CA1 (dCA1 neurons respond to both spatial stimuli and footshock, suggesting that dCA1 could be one such region. We report that, in both dorsal and ventral hippocampus, different neuronal ensembles express immediate-early genes when a place is experienced alone vs. when it is associated with foot shock. We assessed changes in the size and overlap of hippocampal neuronal ensembles activated by two behavioral events using a cellular imaging method, Arc/Homer1a catFISH. The control group (A-A experienced the same place twice, while the experimental group (A-CFC received the same training plus two foot shocks during the second event. During fear conditioning, A-CFC, compared to A-A, rats had a smaller ensemble size in dCA3, dCA1 and vCA3, but not vCA1. Additionally, A-CFC rats had a lower overlap score in dCA1 and vCA3. Locomotion did not correlate with ensemble size. Importantly, foot shocks delivered in a training paradigm that prevents establishing shock-context associations, did not induce significant Arc expression, rejecting the possibility that the observed changes in ensemble size and composition simply reflect experiencing a foot shock. Combined with data that Arc is necessary for lasting synaptic plasticity and long-term memory, the data suggests that Arc/H1a+ hippocampal neuronal ensembles encode aspects of fear conditioning beyond space and time. Rats, like humans, may use the hippocampus to create integrated episodic-like memory during fear conditioning.

Separating discriminative and function-altering effects of verbal stimuli

OpenAIRE

Schlinger, Henry D.

1993-01-01

Ever since Skinner's first discussion of rule-governed behavior, behavior analysts have continued to define rules, either explicitly or implicitly, as verbal discriminative stimuli. Consequently, it is not difficult to find, in the literature on rule-governed behavior, references to stimulus control, antecedent control, or to rules occasioning behavior. However, some verbal stimuli have effects on behavior that are not easily described as discriminative. Such stimuli don't evoke behavior as d...

Sex-related memory recall and talkativeness for emotional stimuli

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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.

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.

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

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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.

Multi-Functional Stimuli-Responsive Materials

Data.gov (United States)

National Aeronautics and Space Administration — Supramolecular polymers based on non-covalent interactions can display a wide array of stimuli-responsive attributes. They can be tailored to change shape, actuate...

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

Science.gov (United States)

Oppitz, Sheila Jacques; Didoné, Dayane Domeneghini; Silva, Débora Durigon da; Gois, Marjana; Folgearini, Jordana; Ferreira, Geise Corrêa; Garcia, Michele Vargas

2015-01-01

Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000Hz - frequent and 4000Hz - rare); and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare). Considering the component N2 for tone burst, the lowest latency found was 217.45ms for the BA/DI stimulus; the highest latency found was 256.5ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

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

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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.

Food-related attentional bias. Word versus pictorial stimuli and the importance of stimuli calorific value in the dot probe task.

Science.gov (United States)

Freijy, Tanya; Mullan, Barbara; Sharpe, Louise

2014-12-01

The primary aim of this study was to extend previous research on food-related attentional biases by examining biases towards pictorial versus word stimuli, and foods of high versus low calorific value. It was expected that participants would demonstrate greater biases to pictures over words, and to high-calorie over low-calorie foods. A secondary aim was to examine associations between BMI, dietary restraint, external eating and attentional biases. It was expected that high scores on these individual difference variables would be associated with a bias towards high-calorie stimuli. Undergraduates (N = 99) completed a dot probe task including matched word and pictorial food stimuli in a controlled setting. Questionnaires assessing eating behaviour were administered, and height and weight were measured. Contrary to predictions, there were no main effects for stimuli type (pictures vs words) or calorific value (high vs low). There was, however, a significant interaction effect suggesting a bias towards high-calorie pictures, but away from high-calorie words; and a bias towards low-calorie words, but away from low-calorie pictures. No associations between attentional bias and any of the individual difference variables were found. The presence of a stimulus type by calorific value interaction demonstrates the importance of stimuli type in the dot probe task, and may help to explain inconsistencies in prior research. Further research is needed to clarify associations between attentional bias and BMI, restraint, and external eating. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

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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.

Lingering representations of stimuli influence recall organization

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Chan, Stephanie C.Y.; Applegate, Marissa C.; Morton, Neal W; Polyn, Sean M.; Norman, Kenneth A.

2017-01-01

Several prominent theories posit that information about recent experiences lingers in the brain and organizes memories for current experiences, by forming a temporal context that is linked to those memories at encoding. According to these theories, if the thoughts preceding an experience X resemble the thoughts preceding an experience Y, then X and Y should show an elevated probability of being recalled together. We tested this prediction by using multi-voxel pattern analysis (MVPA) of fMRI data to measure neural evidence for lingering processing of preceding stimuli. As predicted, memories encoded with similar lingering thoughts about the category of preceding stimuli were more likely to be recalled together. Our results demonstrate that the “fading embers” of previous stimuli help to organize recall, confirming a key prediction of computational models of episodic memory. PMID:28132858

Lingering representations of stimuli influence recall organization.

Science.gov (United States)

Chan, Stephanie C Y; Applegate, Marissa C; Morton, Neal W; Polyn, Sean M; Norman, Kenneth A

2017-03-01

Several prominent theories posit that information about recent experiences lingers in the brain and organizes memories for current experiences, by forming a temporal context that is linked to those memories at encoding. According to these theories, if the thoughts preceding an experience X resemble the thoughts preceding an experience Y, then X and Y should show an elevated probability of being recalled together. We tested this prediction by using multi-voxel pattern analysis (MVPA) of fMRI data to measure neural evidence for lingering processing of preceding stimuli. As predicted, memories encoded with similar lingering thoughts about the category of preceding stimuli were more likely to be recalled together. Our results demonstrate that the "fading embers" of previous stimuli help to organize recall, confirming a key prediction of computational models of episodic memory. Copyright © 2017 Elsevier Ltd. All rights reserved.

The mere exposure effect with scene stimuli

OpenAIRE

八木　, 善彦

2016-01-01

　The mere exposure effect refers to the phenomenon where previous exposures to stimuli increasesubsequent affective preference for those stimuli. It has been indicated that with specific stimulus-category（i.e., paintings, matrices, and photographs of scene）, repeated exposure has little or oppositeeffect on affective ratings. In this study, two experiments were conducted in order to explore theeffect of stimulus-category on the mere exposure effects. Photographs of young woman’s（Experiment1）a...

Vection is modulated by the semantic meaning of stimuli and experimental instructions.

Science.gov (United States)

Ogawa, Masaki; Seno, Takeharu

2014-01-01

Vection strength is modulated by the semantic meanings of stimuli. In experiment 1--even though vection stimuli were of uniform size, color, and luminance--when they also had semantic meaning as falling objects, vection was inhibited. Specifically, stimuli perceived as feathers, petals, and leaves did not effectively induce vection. In experiment 2 we used the downward motion of identical dots to induce vection. Participants observed stimuli while holding either an umbrella or a wooden sword. Results showed that vection was inhibited when participants held the umbrella and the stimuli was perceived as rain or snow falling. The two experiments suggest that vection is modulated by the semantic meaning of stimuli.

Perceptual multistability in figure-ground segregation using motion stimuli.

Science.gov (United States)

Gori, Simone; Giora, Enrico; Pedersini, Riccardo

2008-11-01

In a series of experiments using ambiguous stimuli, we investigate the effects of displaying ordered, discrete series of images on the dynamics of figure-ground segregation. For low frame presentation speeds, the series were perceived as a sequence of discontinuous, static images, while for high speeds they were perceived as continuous. We conclude that using stimuli varying continuously along one parameter results in stronger hysteresis and reduces spontaneous switching compared to matched static stimuli with discontinuous parameter changes. The additional evidence that the size of the hysteresis effects depended on trial duration is consistent with the stochastic nature of the dynamics governing figure-ground segregation. The results showed that for continuously changing stimuli, alternative figure-ground organizations are resolved via low-level, dynamical competition. A second series of experiments confirmed these results with an ambiguous stimulus based on Petter's effect.

Generating Stimuli for Neuroscience Using PsychoPy.

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Peirce, Jonathan W

2008-01-01

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

Teaching children with autism spectrum disorder to tact olfactory stimuli.

Science.gov (United States)

Dass, Tina K; Kisamore, April N; Vladescu, Jason C; Reeve, Kenneth F; Reeve, Sharon A; Taylor-Santa, Catherine

2018-05-28

Research on tact acquisition by children with autism spectrum disorder (ASD) has often focused on teaching participants to tact visual stimuli. It is important to evaluate procedures for teaching tacts of nonvisual stimuli (e.g., olfactory, tactile). The purpose of the current study was to extend the literature on secondary target instruction and tact training by evaluating the effects of a discrete-trial instruction procedure involving (a) echoic prompts, a constant prompt delay, and error correction for primary targets; (b) inclusion of secondary target stimuli in the consequent portion of learning trials; and (c) multiple exemplar training on the acquisition of item tacts of olfactory stimuli, emergence of category tacts of olfactory stimuli, generalization of category tacts, and emergence of category matching, with three children diagnosed with ASD. Results showed that all participants learned the item and category tacts following teaching, participants demonstrated generalization across category tacts, and category matching emerged for all participants. © 2018 Society for the Experimental Analysis of Behavior.

Generating stimuli for neuroscience using PsychoPy

Directory of Open Access Journals (Sweden)

Jonathan W Peirce

2009-01-01

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

Interpretative bias in spider phobia: Perception and information processing of ambiguous schematic stimuli.

Science.gov (United States)

Haberkamp, Anke; Schmidt, Filipp

2015-09-01

This study investigates the interpretative bias in spider phobia with respect to rapid visuomotor processing. We compared perception, evaluation, and visuomotor processing of ambiguous schematic stimuli between spider-fearful and control participants. Stimuli were produced by gradually morphing schematic flowers into spiders. Participants rated these stimuli related to their perceptual appearance and to their feelings of valence, disgust, and arousal. Also, they responded to the same stimuli within a response priming paradigm that measures rapid motor activation. Spider-fearful individuals showed an interpretative bias (i.e., ambiguous stimuli were perceived as more similar to spiders) and rated spider-like stimuli as more unpleasant, disgusting, and arousing. However, we observed no differences between spider-fearful and control participants in priming effects for ambiguous stimuli. For non-ambiguous stimuli, we observed a similar enhancement for phobic pictures as has been reported previously for natural images. We discuss our findings with respect to the visual representation of morphed stimuli and to perceptual learning processes. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

Cassidy

1999-01-01

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

Positive mood broadens visual attention to positive stimuli.

Science.gov (United States)

Wadlinger, Heather A; Isaacowitz, Derek M

2006-03-01

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

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

DEFF Research Database (Denmark)

Gondan, Matthias

2009-01-01

distributions of response times for the single-modality stimuli. It has been derived for synchronous stimuli and for stimuli with stimulus onset asynchrony (SOA). In most experiments with asynchronous stimuli, discrete SOA values are chosen and the race model inequality is separately tested for each SOA. Due...... to SOAs at which the violation of the race model prediction is expected to be large. In addition, the method enables data analysis for experiments in which stimuli are presented with SOA from a continuous distribution rather than in discrete steps.......In speeded response tasks with redundant signals, parallel processing of the signals is tested by the race model inequality. This inequality states that given a race of two signals, the cumulative distribution of response times for redundant stimuli never exceeds the sum of the cumulative...

Generating Stimuli for Neuroscience Using PsychoPy

OpenAIRE

Peirce, Jonathan W.

2009-01-01

PsychoPy is a software library written in Python, using OpenGL to generate very precise visual stimuli on standard personal computers. It is designed to allow the construction of as wide a variety of neuroscience experiments as possible, with the least effort. By writing scripts in standard Python syntax users can generate an enormous variety of visual and auditory stimuli and can interact with a wide range of external hardware (enabling its use in fMRI, EEG, MEG etc.). The structure of scrip...

Stimuli-responsive liquid crystalline materials

NARCIS (Netherlands)

Debije, M.G.; Schenning, A.P.H.J.; Hashmi, Saleem

2016-01-01

Stimuli-responsive materials which respond to triggers from the environment by changing their properties are one of the focal points in materials science. For precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals

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

Analyzing the user behavior towards Electronic Commerce stimuli

OpenAIRE

Carlota Lorenzo-Romero; María-del-Carmen Alarcón-del-Amo

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 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 resea...

Investigation of size effect on film type haptic actuator made with cellulose acetate

International Nuclear Information System (INIS)

Kim, Sang-Youn; Kim, Jaehwan; Kim, Ki-Baek

2014-01-01

The most important factor in haptic interaction with hand-held devices is to develop a thin film type actuator which can be easily inserted into the devices and create vibrotactile signals with wide frequency bandwidth. This paper reports a film type vibrotactile actuator which is tiny enough to be embedded into small hand-held devices. The vibration mechanism and experiment results for the suggested vibrotactile actuator are explained. The aim of the actuator is to convey a vibrotactile force greater than a human’s vibrotactile threshold with broad frequency bandwidth to users. To achieve the requirement, we fabricate a film type vibrotactile actuator with cellulose acetate. When an AC voltage is applied to the actuator, the cellulose acetate film gets charged and then generates vibration. The suggested vibrotactile actuator is fabricated in two sizes: 50 mm × 25 mm and 25 mm × 25 mm. For each size of actuator, three kinds of actuator are fabricated with different pillar materials to support the cellulose acetate films. An experiment for measuring vibrational amplitude is conducted over a wide frequency range of actuation voltage. It is known that the proposed film type actuator is feasible for haptic application in the small hand-held devices. (paper)

Haptic and Audio-visual Stimuli: Enhancing Experiences and Interaction

NARCIS (Netherlands)

Nijholt, Antinus; Dijk, Esko O.; Lemmens, Paul M.C.; Luitjens, S.B.

2010-01-01

The intention of the symposium on Haptic and Audio-visual stimuli at the EuroHaptics 2010 conference is to deepen the understanding of the effect of combined Haptic and Audio-visual stimuli. The knowledge gained will be used to enhance experiences and interactions in daily life. To this end, a

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…

The Hedonic Haptic Player

DEFF Research Database (Denmark)

Vallgårda, Anna; Boer, Laurens; Cahill, Ben

2017-01-01

In this design case we present the Hedonic Haptic Player—a wearable device that plays different patterns of vibrations on the body as a form of music for the skin. With this we begin to explore the enjoyability of vibrations in a wearable set-up. Instead of implementing vibrations as a haptic...... output for some form of communication we want to explore their hedonistic value. The process leading up to the Hedonic Haptic player served as a first step in getting a grasp of the design space of vibrotactile stimuli in a broader sense. This is reported as seven episodes of explorations. The Hedonic...

Dopamine modulates reward system activity during subconscious processing of sexual stimuli.

Science.gov (United States)

Oei, Nicole Y L; Rombouts, Serge Arb; Soeter, Roelof P; van Gerven, Joop M; Both, Stephanie

2012-06-01

Dopaminergic medication influences conscious processing of rewarding stimuli, and is associated with impulsive-compulsive behaviors, such as hypersexuality. Previous studies have shown that subconscious subliminal presentation of sexual stimuli activates brain areas known to be part of the 'reward system'. In this study, it was hypothesized that dopamine modulates activation in key areas of the reward system, such as the nucleus accumbens, during subconscious processing of sexual stimuli. Young healthy males (n=53) were randomly assigned to two experimental groups or a control group, and were administered a dopamine antagonist (haloperidol), a dopamine agonist (levodopa), or placebo. Brain activation was assessed during a backward-masking task with subliminally presented sexual stimuli. Results showed that levodopa significantly enhanced the activation in the nucleus accumbens and dorsal anterior cingulate when subliminal sexual stimuli were shown, whereas haloperidol decreased activations in those areas. Dopamine thus enhances activations in regions thought to regulate 'wanting' in response to potentially rewarding sexual stimuli that are not consciously perceived. This running start of the reward system might explain the pull of rewards in individuals with compulsive reward-seeking behaviors such as hypersexuality and patients who receive dopaminergic medication.

Stimuli-responsive magnetic particles for biomedical applications.

Science.gov (United States)

Medeiros, S F; Santos, A M; Fessi, H; Elaissari, A

2011-01-17

In recent years, magnetic nanoparticles have been studied due to their potential applications as magnetic carriers in biomedical area. These materials have been increasingly exploited as efficient delivery vectors, leading to opportunities of use as magnetic resonance imaging (MRI) agents, mediators of hyperthermia cancer treatment and in targeted therapies. Much attention has been also focused on "smart" polymers, which are able to respond to environmental changes, such as changes in the temperature and pH. In this context, this article reviews the state-of-the art in stimuli-responsive magnetic systems for biomedical applications. The paper describes different types of stimuli-sensitive systems, mainly temperature- and pH sensitive polymers, the combination of this characteristic with magnetic properties and, finally, it gives an account of their preparation methods. The article also discusses the main in vivo biomedical applications of such materials. A survey of the recent literature on various stimuli-responsive magnetic gels in biomedical applications is also included. Copyright © 2010 Elsevier B.V. All rights reserved.

Analyzing the User Behavior toward Electronic Commerce Stimuli

OpenAIRE

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 res...

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.

Do emotional stimuli enhance or impede recall relative to neutral stimuli? An investigation of two "false memory" tasks.

Science.gov (United States)

Monds, Lauren A; Paterson, Helen M; Kemp, Richard I

2017-09-01

Many eyewitness memory situations involve negative and distressing events; however, many studies investigating "false memory" phenomena use neutral stimuli only. The aim of the present study was to determine how both the Deese-Roediger-McDermott (DRM) procedure and the Misinformation Effect Paradigm tasks were related to each other using distressing and neutral stimuli. Participants completed the DRM (with negative and neutral word lists) and viewed a distressing or neutral film. Misinformation for the film was introduced and memory was assessed. Film accuracy and misinformation susceptibility were found to be greater for those who viewed the distressing film relative to the neutral film. Accuracy responses on both tasks were related, however, susceptibility to the DRM illusion and Misinformation Effect were not. The misinformation findings support the Paradoxical Negative Emotion (PNE) hypothesis that negative stimuli will lead to remembering more accurate details but also greater likelihood of memory distortion. However, the PNE hypothesis was not supported for the DRM results. The findings also suggest that the DRM and Misinformation tasks are not equivalent and may have differences in underlying mechanisms. Future research should focus on more ecologically valid methods of assessing false memory.

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.

Auditory-visual aversive stimuli modulate the conscious experience of fear.

Science.gov (United States)

Taffou, Marine; Guerchouche, Rachid; Drettakis, George; Viaud-Delmon, Isabelle

2013-01-01

In a natural environment, affective information is perceived via multiple senses, mostly audition and vision. However, the impact of multisensory information on affect remains relatively undiscovered. In this study, we investigated whether the auditory-visual presentation of aversive stimuli influences the experience of fear. We used the advantages of virtual reality to manipulate multisensory presentation and to display potentially fearful dog stimuli embedded in a natural context. We manipulated the affective reactions evoked by the dog stimuli by recruiting two groups of participants: dog-fearful and non-fearful participants. The sensitivity to dog fear was assessed psychometrically by a questionnaire and also at behavioral and subjective levels using a Behavioral Avoidance Test (BAT). Participants navigated in virtual environments, in which they encountered virtual dog stimuli presented through the auditory channel, the visual channel or both. They were asked to report their fear using Subjective Units of Distress. We compared the fear for unimodal (visual or auditory) and bimodal (auditory-visual) dog stimuli. Dog-fearful participants as well as non-fearful participants reported more fear in response to bimodal audiovisual compared to unimodal presentation of dog stimuli. These results suggest that fear is more intense when the affective information is processed via multiple sensory pathways, which might be due to a cross-modal potentiation. Our findings have implications for the field of virtual reality-based therapy of phobias. Therapies could be refined and improved by implicating and manipulating the multisensory presentation of the feared situations.

Absent Audiovisual Integration Elicited by Peripheral Stimuli in Parkinson's Disease.

Science.gov (United States)

Ren, Yanna; Suzuki, Keisuke; Yang, Weiping; Ren, Yanling; Wu, Fengxia; Yang, Jiajia; Takahashi, Satoshi; Ejima, Yoshimichi; Wu, Jinglong; Hirata, Koichi

2018-01-01

The basal ganglia, which have been shown to be a significant multisensory hub, are disordered in Parkinson's disease (PD). This study was to investigate the audiovisual integration of peripheral stimuli in PD patients with/without sleep disturbances. Thirty-six age-matched normal controls (NC) and 30 PD patients were recruited for an auditory/visual discrimination experiment. The mean response times for each participant were analyzed using repeated measures ANOVA and race model. The results showed that the response to all stimuli was significantly delayed for PD compared to NC (all p audiovisual stimuli was significantly faster than that to unimodal stimuli in both NC and PD ( p audiovisual integration was absent in PD; however, it did occur in NC. Further analysis showed that there was no significant audiovisual integration in PD with/without cognitive impairment or in PD with/without sleep disturbances. Furthermore, audiovisual facilitation was not associated with Hoehn and Yahr stage, disease duration, or the presence of sleep disturbances (all p > 0.05). The current results showed that audiovisual multisensory integration for peripheral stimuli is absent in PD regardless of sleep disturbances and further suggested the abnormal audiovisual integration might be a potential early manifestation of PD.

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.

[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.

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

A Dual-Stimuli-Responsive Sodium-Bromine Battery with Ultrahigh Energy Density.

Science.gov (United States)

Wang, Faxing; Yang, Hongliu; Zhang, Jian; Zhang, Panpan; Wang, Gang; Zhuang, Xiaodong; Cuniberti, Gianaurelio; Feng, Xinliang

2018-06-01

Stimuli-responsive energy storage devices have emerged for the fast-growing popularity of intelligent electronics. However, all previously reported stimuli-responsive energy storage devices have rather low energy densities (energy density, electrochromic effect, and fast thermal response is demonstrated. Remarkably, the fabricated Na//Br 2 battery exhibits a large operating voltage of 3.3 V and an energy density up to 760 Wh kg -1 , which outperforms those for the state-of-the-art stimuli-responsive electrochemical energy storage devices. This work offers a promising approach for designing multi-stimuli-responsive and high-energy rechargeable batteries without sacrificing the electrochemical performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Perceptual Space of Superimposed Dual-Frequency Vibrations in the Hands.

Science.gov (United States)

Hwang, Inwook; Seo, Jeongil; Choi, Seungmoon

2017-01-01

The use of distinguishable complex vibrations that have multiple spectral components can improve the transfer of information by vibrotactile interfaces. We investigated the qualitative characteristics of dual-frequency vibrations as the simplest complex vibrations compared to single-frequency vibrations. Two psychophysical experiments were conducted to elucidate the perceptual characteristics of these vibrations by measuring the perceptual distances among single-frequency and dual-frequency vibrations. The perceptual distances of dual-frequency vibrations between their two frequency components along their relative intensity ratio were measured in Experiment I. The estimated perceptual spaces for three frequency conditions showed non-linear perceptual differences between the dual-frequency and single-frequency vibrations. A perceptual space was estimated from the measured perceptual distances among ten dual-frequency compositions and five single-frequency vibrations in Experiment II. The effect of the component frequency and the frequency ratio was revealed in the perceptual space. In a percept of dual-frequency vibration, the lower frequency component showed a dominant effect. Additionally, the perceptual difference among single-frequency and dual-frequency vibrations were increased with a low relative difference between two frequencies of a dual-frequency vibration. These results are expected to provide a fundamental understanding about the perception of complex vibrations to enrich the transfer of information using vibrotactile stimuli.

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

Science.gov (United States)

Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

2007-03-20

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

Heightened attentional capture by visual food stimuli in Anorexia Nervosa

NARCIS (Netherlands)

Neimeijer, Renate A.M.; Roefs, Anne; de Jong, Peter J.

The present study was designed to test the hypothesis that anorexia nervosa (AN) patients are relatively insensitive to the attentional capture of visual food stimuli. Attentional avoidance of food might help AN patients to prevent more elaborate processing of food stimuli and the subsequent

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

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

Decoding a Decision Process in the Neuronal Population of Dorsal Premotor Cortex.

Science.gov (United States)

Rossi-Pool, Román; Zainos, Antonio; Alvarez, Manuel; Zizumbo, Jerónimo; Vergara, José; Romo, Ranulfo

2017-12-20

When trained monkeys discriminate the temporal structure of two sequential vibrotactile stimuli, dorsal premotor cortex (DPC) showed high heterogeneity among its neuronal responses. Notably, DPC neurons coded stimulus patterns as broader categories and signaled them during working memory, comparison, and postponed decision periods. Here, we show that such population activity can be condensed into two major coding components: one that persistently represented in working memory both the first stimulus identity and the postponed informed choice and another that transiently coded the initial sensory information and the result of the comparison between the two stimuli. Additionally, we identified relevant signals that coded the timing of task events. These temporal and task-parameter readouts were shown to be strongly linked to the monkeys' behavior when contrasted to those obtained in a non-demanding cognitive control task and during error trials. These signals, hidden in the heterogeneity, were prominently represented by the DPC population response. Copyright © 2017 Elsevier Inc. All rights reserved.

Anagrus breviphragma Soyka Short Distance Search Stimuli

Directory of Open Access Journals (Sweden)

Elisabetta Chiappini

2015-01-01

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

Pedophilic brain potential responses to adult erotic stimuli.

Science.gov (United States)

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

2016-02-01

Cognitive mechanisms associated with the relative lack of sexual interest in adults by pedophiles are poorly understood and may benefit from investigations examining how the brain processes adult erotic stimuli. The current study used event-related brain potentials (ERP) to investigate the time course of the explicit processing of erotic, emotional, and neutral pictures in 22 pedophilic patients and 22 healthy controls. Consistent with previous studies, early latency anterior ERP components were highly selective for erotic pictures. Although the ERPs elicited by emotional stimuli were similar in patients and controls, an early frontal positive (P2) component starting as early as 185 ms was significantly attenuated and slow to onset in pedophilia, and correlated with a clinical measure of cognitive distortions. Failure of rapid attentional capture by erotic stimuli suggests a relative reduction in early processing in pedophilic patients which may be associated with relatively diminished sexual interest in adults. Copyright © 2016. Published by Elsevier B.V.

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.

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

Science.gov (United States)

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

2012-01-01

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

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

Rule-violations sensitise towards negative and authority-related stimuli.

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Wirth, Robert; Foerster, Anna; Rendel, Hannah; Kunde, Wilfried; Pfister, Roland

2018-05-01

Rule violations have usually been studied from a third-person perspective, identifying situational factors that render violations more or less likely. A first-person perspective of the agent that actively violates the rules, on the other hand, is only just beginning to emerge. Here we show that committing a rule violation sensitises towards subsequent negative stimuli as well as subsequent authority-related stimuli. In a Prime-Probe design, we used an instructed rule-violation task as the Prime and a word categorisation task as the Probe. Also, we employed a control condition that used a rule inversion task as the Prime (instead of rule violations). Probe targets were categorised faster after a violation relative to after a rule-based response if they related to either, negative valence or authority. Inversions, however, primed only negative stimuli and did not accelerate the categorisation of authority-related stimuli. A heightened sensitivity towards authority-related targets thus seems to be specific to rule violations. A control experiment showed that these effects cannot be explained in terms of semantic priming. Therefore, we propose that rule violations necessarily activate authority-related representations that make rule violations qualitatively different from simple rule inversions.

Cortical oscillations modulated by congruent and incongruent audiovisual stimuli.

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Herdman, A T; Fujioka, T; Chau, W; Ross, B; Pantev, C; Picton, T W

2004-11-30

Congruent or incongruent grapheme-phoneme stimuli are easily perceived as one or two linguistic objects. The main objective of this study was to investigate the changes in cortical oscillations that reflect the processing of congruent and incongruent audiovisual stimuli. Graphemes were Japanese Hiragana characters for four different vowels (/a/, /o/, /u/, and /i/). They were presented simultaneously with their corresponding phonemes (congruent) or non-corresponding phonemes (incongruent) to native-speaking Japanese participants. Participants' reaction times to the congruent audiovisual stimuli were significantly faster by 57 ms as compared to reaction times to incongruent stimuli. We recorded the brain responses for each condition using a whole-head magnetoencephalograph (MEG). A novel approach to analysing MEG data, called synthetic aperture magnetometry (SAM), was used to identify event-related changes in cortical oscillations involved in audiovisual processing. The SAM contrast between congruent and incongruent responses revealed greater event-related desynchonization (8-16 Hz) bilaterally in the occipital lobes and greater event-related synchronization (4-8 Hz) in the left transverse temporal gyrus. Results from this study further support the concept of interactions between the auditory and visual sensory cortices in multi-sensory processing of audiovisual objects.

Low dose intranasal oxytocin delivered with Breath Powered device dampens amygdala response to emotional stimuli: A peripheral effect-controlled within- subjects randomized dose-response fMRI trial

OpenAIRE

Quintana, Daniel; Westlye, Lars Tjelta; Alnæs, Dag; Rustan, Øyvind; Kaufmann, Tobias; Smerud, Knut Terje; Mahmoud, Ramy; Djupesland, Per G.; Andreassen, Ole Andreas

2016-01-01

It is unclear if and how exogenous oxytocin (OT) reaches the brain to improve social behavior and cognition and what is the optimal dose for OT response. To better understand the delivery routes of intranasal OT administration to the brain and the dose-response, we compared amygdala response to facial stimuli by means of functional magnetic resonance imaging (fMRI) in four treatment conditions, including two different doses of intranasal OT using a novel Breath Powered device, intravenous (IV...

Attentional Capture by Emotional Stimuli Is Modulated by Semantic Processing

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Huang, Yang-Ming; Baddeley, Alan; Young, Andrew W.

2008-01-01

The attentional blink paradigm was used to examine whether emotional stimuli always capture attention. The processing requirement for emotional stimuli in a rapid sequential visual presentation stream was manipulated to investigate the circumstances under which emotional distractors capture attention, as reflected in an enhanced attentional blink…

Perceptual load modifies processing of unattended stimuli both in the presence and absence of attended stimuli.

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Couperus, J W

2010-11-26

This study explored effects of perceptual load on stimulus processing in the presence and absence of an attended stimulus. Participants were presented with a bilateral or unilateral display and asked to perform a discrimination task at either low or high perceptual load. Electrophysiological responses to stimuli were then compared at the P100 and N100. As in previous studies, perceptual load modified processing of attended and unattended stimuli seen at occipital scalp sites. Moreover, perceptual load modulated attention effects when the attended stimulus was presented at high perceptual load for unilateral displays. However, this was not true when the attended and unattended stimulus appeared simultaneously in bilateral displays. Instead, only a main effect of perceptual load was found. Reductions in processing contralateral to the unattended stimulus at the N100 provide support for Lavie's (1995) theory of selective attention. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

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.

Happiness takes you right: the effect of emotional stimuli on line bisection.

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Cattaneo, Zaira; Lega, Carlotta; Boehringer, Jana; Gallucci, Marcello; Girelli, Luisa; Carbon, Claus-Christian

2014-01-01

Emotion recognition is mediated by a complex network of cortical and subcortical areas, with the two hemispheres likely being differently involved in processing positive and negative emotions. As results on valence-dependent hemispheric specialisation are quite inconsistent, we carried out three experiments with emotional stimuli with a task being sensitive to measure specific hemispheric processing. Participants were required to bisect visual lines that were delimited by emotional face flankers, or to haptically bisect rods while concurrently listening to emotional vocal expressions. We found that prolonged (but not transient) exposition to concurrent happy stimuli significantly shifted the bisection bias to the right compared to both sad and neutral stimuli, indexing a greater involvement of the left hemisphere in processing of positively connoted stimuli. No differences between sad and neutral stimuli were observed across the experiments. In sum, our data provide consistent evidence in favour of a greater involvement of the left hemisphere in processing positive emotions and suggest that (prolonged) exposure to stimuli expressing happiness significantly affects allocation of (spatial) attentional resources, regardless of the sensory (visual/auditory) modality in which the emotion is perceived and space is explored (visual/haptic).

Multisensory stimuli improve relative localisation judgments compared to unisensory auditory or visual stimuli

OpenAIRE

Bizley, Jennifer; Wood, Katherine; Freeman, Laura

2018-01-01

Observers performed a relative localisation task in which they reported whether the second of two sequentially presented signals occurred to the left or right of the first. Stimuli were detectability-matched auditory, visual, or auditory-visual signals and the goal was to compare changes in performance with eccentricity across modalities. Visual performance was superior to auditory at the midline, but inferior in the periphery, while auditory-visual performance exceeded both at all locations....

Opposing Subjective Temporal Experiences in Response to Unpredictable and Predictable Fear-Relevant Stimuli

Directory of Open Access Journals (Sweden)

Qian Cui

2018-03-01

Full Text Available Previous studies have found that the durations of fear-relevant stimuli were overestimated compared to those of neutral stimuli, even when the fear-relevant stimuli were only anticipated. The current study aimed to investigate the effect of the predictability of fear-relevant stimuli on sub-second temporal estimations. In Experiments 1a and 1b, a randomized design was employed to render the emotional valence of each trial unpredictable. In Experiments 2a and 2b, we incorporated a block design and a cueing paradigm, respectively, to render the emotional stimuli predictable. Compared with the neutral condition, the estimated blank interval was judged as being shorter under the unpredictable fear-relevant condition, while it was judged as being longer under the predictable fear-relevant condition. In other words, the unpredictable and predictable fear-relevant stimuli led to opposing temporal distortions. These results demonstrated that emotions modulate interval perception during different time processing stages.

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

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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…

Dynamism of Stimuli-Responsive Nanohybrids: Environmental Implications

Directory of Open Access Journals (Sweden)

Jaime Plazas-Tuttle

2015-06-01

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

Attention bias towards personally relevant stimuli: the individual emotional Stroop task.

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Wingenfeld, Katja; Bullig, Renate; Mensebach, Christoph; Hartje, Wolfgang; Driessen, Martin; Beblo, Thomas

2006-12-01

The emotional Stroop task is a widely used method for investigating attentional bias towards stimuli due to mood or affect. In general, standardized stimuli are used, which might not be appropriate when investigating individual contextual frameworks. It was investigated whether words chosen to be related to individuals' personal life events would produce more pronounced Stroop interference (as an indicator of attentional bias) than stimuli without any personal relevance. Twenty-six nonclinical subjects, 20 female and 6 male, participated in the study. Mean age was 36.1 yr. (SD = 18.1). All were recruited by means of local advertising. Stimulus material consisted of four word types: personal words related to negative life events with and without current personal relevance, and negative and neutral words without any personal relevance. Words were presented in three blocks. Analysis of variance showed main effects for word type and blocks, with slower reactions in the personally relevant conditions than in the negative, or neutral conditions, and in response to the first blocks as opposed to the last. These findings indicate that regardless of the word valence, personally relevant stimuli evoke more pronounced Stroop interference than do stimuli without personal relevance.

Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

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

2014-01-01

Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance. PMID:25249947

Associations between Tactile Sensory Threshold and Postural Performance and Effects of Healthy Aging and Subthreshold Vibrotactile Stimulation on Postural Outcomes in a Simple Dual Task

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Dettmer, Marius; Pourmoghaddam, Amir; Lee, Beom-Chan; Layne, Charles S.

2016-01-01

Specific activities that require concurrent processing of postural and cognitive tasks may increase the risk for falls in older adults. We investigated whether peripheral receptor sensitivity was associated with postural performance in a dual-task and whether an intervention in form of subthreshold vibration could affect performance. Ten younger (age: 20–35 years) and ten older adults (70–85 years) performed repeated auditory-verbal 1-back tasks while standing quietly on a force platform. Foot sole vibration was randomly added during several trials. Several postural control and performance measures were assessed and statistically analyzed (significance set to α-levels of .05). There were moderate correlations between peripheral sensitivity and several postural performance and control measures (r = .45 to .59). Several postural performance measures differed significantly between older and younger adults (p older adults' performance in dual-tasks, and peripheral sensitivity may be a contributor to the observed differences. A vibration intervention may only be useful when there are more severe impairments of the sensorimotor system. Hence, future research regarding the efficacy of sensorimotor interventions in the form of vibrotactile stimulation should focus on older adults whose balance is significantly affected. PMID:27143967

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

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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.

Testing aggressive behaviour in a feeding context: Importance of ethologically relevant stimuli.

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González, Daniel; Szenczi, Péter; Bánszegi, Oxána; Hudson, Robyn

2018-05-01

The choice of stimuli used in tests of animal behaviour can have a critical effect on the outcome. Here we report two experiments showing how different foods influenced aggressive behaviour in competition tests at weaning among littermates of the domestic cat. Whereas in Experiment 1 canned food elicited almost no overt competition, a piece of raw beef rib elicited clearly aggressive behaviour among littermates. In Experiment 2 the food stimuli were chosen to differ from raw beef rib in various combinations of taste/smell, texture and monopolizability. Kittens showed different levels of aggression in response to the five stimuli tested, which suggests that the strong effect of beef rib in eliciting aggressive behaviour was due to a complex combination of features. We suggest that using stimuli approximating the evolved, functional significance to the species concerned is more likely to result in robust, biologically relevant behaviours than more artificial stimuli. Copyright © 2018 Elsevier B.V. All rights reserved.

Intimate stimuli result in fronto-parietal activation changes in anorexia nervosa

NARCIS (Netherlands)

van Zutphen, L; Maier, S; Siep, N; Jacob, G A; Tüscher, O; van Elst, L Tebartz; Zeeck, A; Arntz, A; O'Connor, M-F; Stamm, H; Hudek, M; Joos, Andreas

2018-01-01

BACKGROUND: Intimacy is a key psychological problem in anorexia nervosa (AN). Empirical evidence, including neurobiological underpinnings, is however, scarce. OBJECTIVE: In this study, we evaluated various emotional stimuli including intimate stimuli experienced in patients with AN and non-patients,

Secondary hyperalgesia to heat stimuli after burn injury in man

DEFF Research Database (Denmark)

Pedersen, J L; Kehlet, H

1998-01-01

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

Heightened attentional capture by visual food stimuli in anorexia nervosa.

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Neimeijer, Renate A M; Roefs, Anne; de Jong, Peter J

2017-08-01

The present study was designed to test the hypothesis that anorexia nervosa (AN) patients are relatively insensitive to the attentional capture of visual food stimuli. Attentional avoidance of food might help AN patients to prevent more elaborate processing of food stimuli and the subsequent generation of craving, which might enable AN patients to maintain their strict diet. Participants were 66 restrictive AN spectrum patients and 55 healthy controls. A single-target rapid serial visual presentation task was used with food and disorder-neutral cues as critical distracter stimuli and disorder-neutral pictures as target stimuli. AN spectrum patients showed diminished task performance when visual food cues were presented in close temporal proximity of the to-be-identified target. In contrast to our hypothesis, results indicate that food cues automatically capture AN spectrum patients' attention. One explanation could be that the enhanced attentional capture of food cues in AN is driven by the relatively high threat value of food items in AN. Implications and suggestions for future research are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Stress improves selective attention towards emotionally neutral left ear stimuli.

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

2014-09-01

Research concerning the impact of psychological stress on visual selective attention has produced mixed results. The current paper describes two experiments which utilise a novel auditory oddball paradigm to test the impact of psychological stress on auditory selective attention. Participants had to report the location of emotionally-neutral auditory stimuli, while ignoring task-irrelevant changes in their content. The results of the first experiment, in which speech stimuli were presented, suggested that stress improves the ability to selectively attend to left, but not right ear stimuli. When this experiment was repeated using tonal stimuli the same result was evident, but only for female participants. Females were also found to experience greater levels of distraction in general across the two experiments. These findings support the goal-shielding theory which suggests that stress improves selective attention by reducing the attentional resources available to process task-irrelevant information. The study also demonstrates, for the first time, that this goal-shielding effect extends to auditory perception. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of testosterone on attention and memory for emotional stimuli in male rhesus monkeys.

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King, Hanna M; Kurdziel, Laura B; Meyer, Jerrold S; Lacreuse, Agnès

2012-03-01

Increasing evidence in humans and other animals suggests that testosterone (T) plays an important role in modulating emotion. We previously reported that T treatment in rhesus monkeys undergoing chemically induced hypogonadism results in increased watching time of videos depicting fights between unfamiliar conspecifics (Lacreuse et al., 2010). In the current study, we aimed to further investigate the effect of T manipulations on attention and memory for emotional stimuli in male rhesus monkeys. Six males (7 years old) were administered Depot Lupron to suppress endogenous T levels and treated with either testosterone enanthate (TE, 5 mg/kg) or oil, before crossing over to the alternate treatment. Animals were tested for 16 weeks on two computerized touchscreen tasks with both social and nonsocial emotional and neutral stimuli. The Dot-Probe task was used to measure attention, and the Delayed-Non-Matching-to-Sample task with a 1s delay (DNMS) was used to measure recognition memory for these stimuli. Performance on the two tasks was examined during each of four month-long phases: Baseline, Lupron alone, Lupron+TE and Lupron+oil. It was predicted that T administration would lead to increased attention to negative social stimuli (i.e., negative facial expressions of unfamiliar conspecifics) and would improve memory for such stimuli. We found no evidence to support these predictions. In the Dot-Probe task, an attentional bias towards negative social stimuli was observed at baseline, but T treatment did not enhance this bias. Instead, monkeys had faster response times when treated with T compared to oil, independently of the emotional valence or social relevance of stimuli, perhaps reflecting an enhancing effect of T on reward sensitivity or general arousal. In the DNMS, animals had better memory for nonsocial compared to social stimuli and showed the poorest performance in the recognition of positive facial expressions. However, T did not affect performance on the task

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

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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.

Physiological responses induced by pleasant stimuli.

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Watanuki, Shigeki; Kim, Yeon-Kyu

2005-01-01

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

Blind Braille readers mislocate tactile stimuli.

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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.

Psychophysiological effects of audiovisual stimuli during cycle exercise.

Science.gov (United States)

Barreto-Silva, Vinícius; Bigliassi, Marcelo; Chierotti, Priscila; Altimari, Leandro R

2018-05-01

Immersive environments induced by audiovisual stimuli are hypothesised to facilitate the control of movements and ameliorate fatigue-related symptoms during exercise. The objective of the present study was to investigate the effects of pleasant and unpleasant audiovisual stimuli on perceptual and psychophysiological responses during moderate-intensity exercises performed on an electromagnetically braked cycle ergometer. Twenty young adults were administered three experimental conditions in a randomised and counterbalanced order: unpleasant stimulus (US; e.g. images depicting laboured breathing); pleasant stimulus (PS; e.g. images depicting pleasant emotions); and neutral stimulus (NS; e.g. neutral facial expressions). The exercise had 10 min of duration (2 min of warm-up + 6 min of exercise + 2 min of warm-down). During all conditions, the rate of perceived exertion and heart rate variability were monitored to further understanding of the moderating influence of audiovisual stimuli on perceptual and psychophysiological responses, respectively. The results of the present study indicate that PS ameliorated fatigue-related symptoms and reduced the physiological stress imposed by the exercise bout. Conversely, US increased the global activity of the autonomic nervous system and increased exertional responses to a greater degree when compared to PS. Accordingly, audiovisual stimuli appear to induce a psychophysiological response in which individuals visualise themselves within the story presented in the video. In such instances, individuals appear to copy the behaviour observed in the videos as if the situation was real. This mirroring mechanism has the potential to up-/down-regulate the cardiac work as if in fact the exercise intensities were different in each condition.

Effects of auditory stimuli in the horizontal plane on audiovisual integration: an event-related potential study.

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Yang, Weiping; Li, Qi; Ochi, Tatsuya; Yang, Jingjing; Gao, Yulin; Tang, Xiaoyu; Takahashi, Satoshi; Wu, Jinglong

2013-01-01

This article aims to investigate whether auditory stimuli in the horizontal plane, particularly originating from behind the participant, affect audiovisual integration by using behavioral and event-related potential (ERP) measurements. In this study, visual stimuli were presented directly in front of the participants, auditory stimuli were presented at one location in an equidistant horizontal plane at the front (0°, the fixation point), right (90°), back (180°), or left (270°) of the participants, and audiovisual stimuli that include both visual stimuli and auditory stimuli originating from one of the four locations were simultaneously presented. These stimuli were presented randomly with equal probability; during this time, participants were asked to attend to the visual stimulus and respond promptly only to visual target stimuli (a unimodal visual target stimulus and the visual target of the audiovisual stimulus). A significant facilitation of reaction times and hit rates was obtained following audiovisual stimulation, irrespective of whether the auditory stimuli were presented in the front or back of the participant. However, no significant interactions were found between visual stimuli and auditory stimuli from the right or left. Two main ERP components related to audiovisual integration were found: first, auditory stimuli from the front location produced an ERP reaction over the right temporal area and right occipital area at approximately 160-200 milliseconds; second, auditory stimuli from the back produced a reaction over the parietal and occipital areas at approximately 360-400 milliseconds. Our results confirmed that audiovisual integration was also elicited, even though auditory stimuli were presented behind the participant, but no integration occurred when auditory stimuli were presented in the right or left spaces, suggesting that the human brain might be particularly sensitive to information received from behind than both sides.

Deciphering molecular circuits from genetic variation underlying transcriptional responsiveness to stimuli.

Science.gov (United States)

Gat-Viks, Irit; Chevrier, Nicolas; Wilentzik, Roni; Eisenhaure, Thomas; Raychowdhury, Raktima; Steuerman, Yael; Shalek, Alex K; Hacohen, Nir; Amit, Ido; Regev, Aviv

2013-04-01

Individual genetic variation affects gene responsiveness to stimuli, often by influencing complex molecular circuits. Here we combine genomic and intermediate-scale transcriptional profiling with computational methods to identify variants that affect the responsiveness of genes to stimuli (responsiveness quantitative trait loci or reQTLs) and to position these variants in molecular circuit diagrams. We apply this approach to study variation in transcriptional responsiveness to pathogen components in dendritic cells from recombinant inbred mouse strains. We identify reQTLs that correlate with particular stimuli and position them in known pathways. For example, in response to a virus-like stimulus, a trans-acting variant responds as an activator of the antiviral response; using RNA interference, we identify Rgs16 as the likely causal gene. Our approach charts an experimental and analytic path to decipher the mechanisms underlying genetic variation in circuits that control responses to stimuli.

Negative emotional stimuli reduce contextual cueing but not response times in inefficient search.

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Kunar, Melina A; Watson, Derrick G; Cole, Louise; Cox, Angeline

2014-02-01

In visual search, previous work has shown that negative stimuli narrow the focus of attention and speed reaction times (RTs). This paper investigates these two effects by first asking whether negative emotional stimuli narrow the focus of attention to reduce the learning of a display context in a contextual cueing task and, second, whether exposure to negative stimuli also reduces RTs in inefficient search tasks. In Experiment 1, participants viewed either negative or neutral images (faces or scenes) prior to a contextual cueing task. In a typical contextual cueing experiment, RTs are reduced if displays are repeated across the experiment compared with novel displays that are not repeated. The results showed that a smaller contextual cueing effect was obtained after participants viewed negative stimuli than when they viewed neutral stimuli. However, in contrast to previous work, overall search RTs were not faster after viewing negative stimuli (Experiments 2 to 4). The findings are discussed in terms of the impact of emotional content on visual processing and the ability to use scene context to help facilitate search.

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

Relationship of extinction to perceptual thresholds for single stimuli.

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Meador, K J; Ray, P G; Day, L J; Loring, D W

2001-04-24

To demonstrate the effects of target stimulus intensity on extinction to double simultaneous stimuli. Attentional deficits contribute to extinction in patients with brain lesions, but extinction (i.e., masking) can also be produced in healthy subjects. The relationship of extinction to perceptual thresholds for single stimuli remains uncertain. Brief electrical pulses were applied simultaneously to the left and right index fingers of 16 healthy volunteers (8 young and 8 elderly adults) and 4 patients with right brain stroke (RBS). The stimulus to be perceived (i.e., target stimulus) was given at the lowest perceptual threshold to perceive any single stimulus (i.e., Minimal) and at the threshold to perceive 100% of single stimuli. The mask stimulus (i.e., stimulus given to block the target) was applied to the contralateral hand at intensities just below discomfort. Extinction was less for target stimuli at 100% than Minimal threshold for healthy subjects. Extinction of left targets was greater in patients with RBS than elderly control subjects. Left targets were extinguished less than right in healthy subjects. In contrast, the majority of left targets were extinguished in patients with RBS even when right mask intensity was reduced below right 100% threshold for single stimuli. RBS patients had less extinction for right targets despite having greater left mask - threshold difference than control subjects. In patients with RBS, right "targets" at 100% threshold extinguished left "masks" (20%) almost as frequently as left masks extinguished right targets (32%). Subtle changes in target intensity affect extinction in healthy adults. Asymmetries in mask and target intensities (relative to single-stimulus perceptual thresholds) affect extinction in RBS patients less for left targets but more for right targets as compared with control subjects.

Activation of right parietal cortex during memory retrieval of nonlinguistic auditory stimuli.

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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.

Oxytocin and vasopressin enhance responsiveness to infant stimuli in adult marmosets.

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Taylor, Jack H; French, Jeffrey A

2015-09-01

The neuropeptides oxytocin (OT) and arginine-vasopressin (AVP) have been implicated in modulating sex-specific responses to offspring in a variety of uniparental and biparental rodent species. Despite the large body of research in rodents, the effects of these hormones in biparental primates are less understood. Marmoset monkeys (Callithrix jacchus) belong to a clade of primates with a high incidence of biparental care and also synthesize a structurally distinct variant of OT (proline instead of leucine at the 8th amino acid position; Pro(8)-OT). We examined the roles of the OT and AVP systems in the control of responses to infant stimuli in marmoset monkeys. We administered neuropeptide receptor agonists and antagonists to male and female marmosets, and then exposed them to visual and auditory infant-related and control stimuli. Intranasal Pro(8)-OT decreased latencies to respond to infant stimuli in males, and intranasal AVP decreased latencies to respond to infant stimuli in females. Our study is the first to demonstrate that Pro(8)-OT and AVP alter responsiveness to infant stimuli in a biparental New World monkey. Across species, the effects of OT and AVP on parental behavior appear to vary by species-typical caregiving responsibilities in males and females. Copyright © 2015 Elsevier Inc. All rights reserved.

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

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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.

Selective processing of linguistic and pictorial food stimuli in females with anorexia and bulimia nervosa.

Science.gov (United States)

Stormark, Kjell Morten; Torkildsen, Øivind

2004-01-01

This study investigated subjects with eating disorders' selective attention to linguistic and pictorial representations of food stimuli in a version of the Stroop color-naming task. If subjects with eating disorders' attention really are biased by food stimuli, one would expect equally delayed color-naming latencies to food pictures as previous studies have found to food words. Twenty females with eating disorders (anorexia nervosa, bulimia nervosa, or a combination of both) and 24 female controls identified the color of Stroop versions of linguistic and pictorial representations of color, food, emotional, and neutral stimuli. The eating disorder group was slower than the controls in identifying the color of all words (including the food words) and the pictures depicting food stimuli (but not any of the other pictures). The eating disorder group was also slower in identifying the color of both food and emotional than neutral stimuli, both for the linguistic and pictorial stimuli. These findings indicate that females with bulimia and anorexia nervosa's biased attention to food stimuli are not restricted to linguistic representations. The delayed responses to the emotional words and pictures suggest that processing of negative emotional stimuli, in addition to dysfunctional concerns about stimuli related to food and eating, is important in the maintenance of eating disorders.

Multiaccommodative stimuli in VR systems: problems & solutions.

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Marran, L; Schor, C

1997-09-01

Virtual reality environments can introduce multiple and sometimes conflicting accommodative stimuli. For instance, with the high-powered lenses commonly used in head-mounted displays, small discrepancies in screen lens placement, caused by manufacturer error or user adjustment focus error, can change the focal depths of the image by a couple of diopters. This can introduce a binocular accommodative stimulus or, if the displacement between the two screens is unequal, an unequal (anisometropic) accommodative stimulus for the two eyes. Systems that allow simultaneous viewing of virtual and real images can also introduce a conflict in accommodative stimuli: When real and virtual images are at different focal planes, both cannot be in focus at the same time, though they may appear to be in similar locations in space. In this paper four unique designs are described that minimize the range of accommodative stimuli and maximize the visual system's ability to cope efficiently with the focus conflicts that remain: pinhole optics, monocular lens addition combined with aniso-accommodation, chromatic bifocal, and bifocal lens system. The advantages and disadvantages of each design are described and recommendation for design choice is given after consideration of the end use of the virtual reality system (e.g., low or high end, entertainment, technical, or medical use). The appropriate design modifications should allow greater user comfort and better performance.

Dissociating object-based from egocentric transformations in mental body rotation: effect of stimuli size.

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Habacha, Hamdi; Moreau, David; Jarraya, Mohamed; Lejeune-Poutrain, Laure; Molinaro, Corinne

2018-01-01

The effect of stimuli size on the mental rotation of abstract objects has been extensively investigated, yet its effect on the mental rotation of bodily stimuli remains largely unexplored. Depending on the experimental design, mentally rotating bodily stimuli can elicit object-based transformations, relying mainly on visual processes, or egocentric transformations, which typically involve embodied motor processes. The present study included two mental body rotation tasks requiring either a same-different or a laterality judgment, designed to elicit object-based or egocentric transformations, respectively. Our findings revealed shorter response times for large-sized stimuli than for small-sized stimuli only for greater angular disparities, suggesting that the more unfamiliar the orientations of the bodily stimuli, the more stimuli size affected mental processing. Importantly, when comparing size transformation times, results revealed different patterns of size transformation times as a function of angular disparity between object-based and egocentric transformations. This indicates that mental size transformation and mental rotation proceed differently depending on the mental rotation strategy used. These findings are discussed with respect to the different spatial manipulations involved during object-based and egocentric transformations.

Newborns' Discrimination of Chromatic from Achromatic Stimuli.

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Adams, Russell J.; And Others

1986-01-01

Two experiments assessed the extent of newborns' ability to discriminate color. Results imply that newborns have some, albeit limited, capacity to discriminate chromatic from achromatic stimuli, and hence, are at least dichromats. (Author/DR)

The sensory channel of presentation alters subjective ratings and autonomic responses towards disgusting stimuli -Blood pressure, heart rate and skin conductance in response to visual, auditory, haptic and olfactory presented disgusting stimuli-

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Ilona eCroy

2013-09-01

Full Text Available Disgust causes specific reaction patterns, observable in mimic responses and body reactions. Most research on disgust deals with visual stimuli. However, pictures may cause another disgust experience than sounds, odors or tactile stimuli. Therefore disgust experience evoked by four different sensory channels was compared.A total of 119 participants received 3 different disgusting and one control stimulus, each presented through the visual, auditory, tactile and olfactory channel. Ratings of evoked disgust as well as responses of the autonomic nervous system (heart rate, skin conductance level, systolic blood pressure were recorded and the effect of stimulus labeling and of repeated presentation was analyzed. Ratings suggested that disgust could be evoked through all senses; they were highest for visual stimuli. However, autonomic reaction towards disgusting stimuli differed according to the channel of presentation. In contrast to the other, olfactory disgust stimuli provoked a strong decrease of systolic blood pressure. Additionally, labeling enhanced disgust ratings and autonomic reaction for olfactory and tactile, but not for visual and auditory stimuli. Repeated presentation indicated that participant’s disgust rating diminishes to all but olfactory disgust stimuli. Taken together we argue that the sensory channel through which a disgust reaction is evoked matters.

When goals conflict with values: counterproductive attentional and oculomotor capture by reward-related stimuli.

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Le Pelley, Mike E; Pearson, Daniel; Griffiths, Oren; Beesley, Tom

2015-02-01

Attention provides the gateway to cognition, by selecting certain stimuli for further analysis. Recent research demonstrates that whether a stimulus captures attention is not determined solely by its physical properties, but is malleable, being influenced by our previous experience of rewards obtained by attending to that stimulus. Here we show that this influence of reward learning on attention extends to task-irrelevant stimuli. In a visual search task, certain stimuli signaled the magnitude of available reward, but reward delivery was not contingent on responding to those stimuli. Indeed, any attentional capture by these critical distractor stimuli led to a reduction in the reward obtained. Nevertheless, distractors signaling large reward produced greater attentional and oculomotor capture than those signaling small reward. This counterproductive capture by task-irrelevant stimuli is important because it demonstrates how external reward structures can produce patterns of behavior that conflict with task demands, and similar processes may underlie problematic behavior directed toward real-world rewards.

Amygdala activity related to enhanced memory for pleasant and aversive stimuli.

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Hamann, S B; Ely, T D; Grafton, S T; Kilts, C D

1999-03-01

Pleasant or aversive events are better remembered than neutral events. Emotional enhancement of episodic memory has been linked to the amygdala in animal and neuropsychological studies. Using positron emission tomography, we show that bilateral amygdala activity during memory encoding is correlated with enhanced episodic recognition memory for both pleasant and aversive visual stimuli relative to neutral stimuli, and that this relationship is specific to emotional stimuli. Furthermore, data suggest that the amygdala enhances episodic memory in part through modulation of hippocampal activity. The human amygdala seems to modulate the strength of conscious memory for events according to emotional importance, regardless of whether the emotion is pleasant or aversive.

Emotional conditioning to masked stimuli and modulation of visuospatial attention.

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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.

Auditory stimulus timing influences perceived duration of co-occurring visual stimuli

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Vincenzo eRomei

2011-09-01

Full Text Available There is increasing interest in multisensory influences upon sensory-specific judgements, such as when auditory stimuli affect visual perception. Here we studied whether the duration of an auditory event can objectively affect the perceived duration of a co-occurring visual event. On each trial, participants were presented with a pair of successive flashes and had to judge whether the first or second was longer. Two beeps were presented with the flashes. The order of short and long stimuli could be the same across audition and vision (audiovisual congruent or reversed, so that the longer flash was accompanied by the shorter beep and vice versa (audiovisual incongruent; or the two beeps could have the same duration as each other. Beeps and flashes could onset synchronously or asynchronously. In a further control experiment, the beep durations were much longer (tripled than the flashes. Results showed that visual duration-discrimination sensitivity (d' was significantly higher for congruent (and significantly lower for incongruent audiovisual synchronous combinations, relative to the visual only presentation. This effect was abolished when auditory and visual stimuli were presented asynchronously, or when sound durations tripled those of flashes. We conclude that the temporal properties of co-occurring auditory stimuli influence the perceived duration of visual stimuli and that this can reflect genuine changes in visual sensitivity rather than mere response bias.

[Effects of visual optical stimuli for accommodation-convergence system on asthenopia].

Science.gov (United States)

Iwasaki, Tsuneto; Tawara, Akihiko; Miyake, Nobuyuki

2006-01-01

We investigated the effect on eyestrain of optical stimuli that we designed for accommodation and convergence systems. Eight female students were given optical stimuli for accommodation and convergence systems for 1.5 min immediately after 20 min of a sustained task on a 3-D display. Before and after the trial, their ocular functions were measured and their symptoms were assessed. The optical stimuli were applied by moving targets of scenery images far and near around the far point position of both eyes on a horizonal place, which induced divergence in the direction of the eye position of rest. In a control group, subjects rested with closed eyes for 1.5 min instead of applying the optical stimuli. There were significant changes in the accommodative contraction time (from far to near) and the accommodative relaxation time (from near to far) and the lag of accommodation at near target, from 1.26 s to 1.62 s and from 1.49 s to 1.63 s and from 0.5 D to 0.65 D, respectively, and in the symptoms in the control group after the duration of closed-eye rest. In the stimulus group, however, the changes of those functions were smaller than in the control group. From these results, we suggest that our designed optical stimuli for accommodation and convergence systems are effective on asthenopia following accommodative dysfunction.

Stimuli-Responsive Materials for Controlled Release Applications

KAUST Repository

Li, Song

2015-01-01

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

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

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

2014-11-01

Only seven cases of agnosia for mirror stimuli have been reported, always with an extensive lesion. We report a new case of an agnosia for mirror stimuli due to a circumscribed lesion. An extensive battery of neuropsychological tests and a new experimental procedure to assess visual object mirror and orientation discrimination were assessed 10 days after the onset of clinical symptoms, and 5 years later. The performances of our patient were compared with those of four healthy control subjects matched for age. This test revealed an agnosia for mirror stimuli. Brain imaging showed a small right occipitoparietal hematoma, encompassing the extrastriate cortex adjoining the inferior parietal lobe. This new case suggests that: (i) agnosia for mirror stimuli can persist for 5 years after onset and (ii) the posterior part of the right intraparietal sulcus could be critical in the cognitive process of mirror stimuli discrimination. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex.

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Bednařík, Petr; Tkáč, Ivan; Giove, Federico; Eberly, Lynn E; Deelchand, Dinesh K; Barreto, Felipe R; Mangia, Silvia

2018-02-01

In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional 1 H MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.

Influence of auditory and audiovisual stimuli on the right-left prevalence effect

DEFF Research Database (Denmark)

Vu, Kim-Phuong L; Minakata, Katsumi; Ngo, Mary Kim

2014-01-01

occurs when the two-dimensional stimuli are audiovisual, as well as whether there will be cross-modal facilitation of response selection for the horizontal and vertical dimensions. We also examined whether there is an additional benefit of adding a pitch dimension to the auditory stimulus to facilitate...... vertical coding through use of the spatial-musical association of response codes (SMARC) effect, where pitch is coded in terms of height in space. In Experiment 1, we found a larger right-left prevalence effect for unimodal auditory than visual stimuli. Neutral, non-pitch coded, audiovisual stimuli did...... not result in cross-modal facilitation, but did show evidence of visual dominance. The right-left prevalence effect was eliminated in the presence of SMARC audiovisual stimuli, but the effect influenced horizontal rather than vertical coding. Experiment 2 showed that the influence of the pitch dimension...

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.

Divided attention enhances the recognition of emotional stimuli: evidence from the attentional boost effect.

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Rossi-Arnaud, Clelia; Spataro, Pietro; Costanzi, Marco; Saraulli, Daniele; Cestari, Vincenzo

2018-01-01

The present study examined predictions of the early-phase-elevated-attention hypothesis of the attentional boost effect (ABE), which suggests that transient increases in attention at encoding, as instantiated in the ABE paradigm, should enhance the recognition of neutral and positive items (whose encoding is mostly based on controlled processes), while having small or null effects on the recognition of negative items (whose encoding is primarily based on automatic processes). Participants were presented a sequence of negative, neutral and positive stimuli (pictures in Experiment 1, words in Experiment 2) associated to target (red) squares, distractor (green) squares or no squares (baseline condition). They were told to attend to the pictures/words and simultaneously press the spacebar of the computer when a red square appeared. In a later recognition task, stimuli associated to target squares were recognised better than stimuli associated to distractor squares, replicating the standard ABE. More importantly, we also found that: (a) the memory enhancement following target detection occurred with all types of stimuli (neutral, negative and positive) and (b) the advantage of negative stimuli over neutral stimuli was intact in the DA condition. These findings suggest that the encoding of negative stimuli depends on both controlled (attention-dependent) and automatic (attention-independent) processes.

Enhancing interaural-delay-based extents of laterality at high frequencies by using ``transposed stimuli''

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Bernstein, Leslie R.; Trahiotis, Constantine

2003-06-01

An acoustic pointing task was used to determine whether interaural temporal disparities (ITDs) conveyed by high-frequency ``transposed'' stimuli would produce larger extents of laterality than ITDs conveyed by bands of high-frequency Gaussian noise. The envelopes of transposed stimuli are designed to provide high-frequency channels with information similar to that conveyed by the waveforms of low-frequency stimuli. Lateralization was measured for low-frequency Gaussian noises, the same noises transposed to 4 kHz, and high-frequency Gaussian bands of noise centered at 4 kHz. Extents of laterality obtained with the transposed stimuli were greater than those obtained with bands of Gaussian noise centered at 4 kHz and, in some cases, were equivalent to those obtained with low-frequency stimuli. In a second experiment, the general effects on lateral position produced by imposed combinations of bandwidth, ITD, and interaural phase disparities (IPDs) on low-frequency stimuli remained when those stimuli were transposed to 4 kHz. Overall, the data were fairly well accounted for by a model that computes the cross-correlation subsequent to known stages of peripheral auditory processing augmented by low-pass filtering of the envelopes within the high-frequency channels of each ear.

Testing food-related inhibitory control to high- and low-calorie food stimuli: Electrophysiological responses to high-calorie food stimuli predict calorie and carbohydrate intake.

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Carbine, Kaylie A; Christensen, Edward; LeCheminant, James D; Bailey, Bruce W; Tucker, Larry A; Larson, Michael J

2017-07-01

Maintaining a healthy diet has important implications for physical and mental health. One factor that may influence diet and food consumption is inhibitory control-the ability to withhold a dominant response in order to correctly respond to environmental demands. We examined how N2 amplitude, an ERP that reflects inhibitory control processes, differed toward high- and low-calorie food stimuli and related to food intake. A total of 159 participants (81 female; M age = 23.5 years; SD = 7.6) completed two food-based go/no-go tasks (one with high-calorie and one with low-calorie food pictures as no-go stimuli) while N2 amplitude was recorded. Participants recorded food intake using the Automated Self-Administered 24-hour Dietary Recall system. Inhibiting responses toward high-calorie stimuli elicited a larger (i.e., more negative) no-go N2 amplitude; inhibiting responses toward low-calorie stimuli elicited a smaller no-go N2 amplitude. Participants were more accurate during the high-calorie than low-calorie task, but took longer to respond on go trials toward high-calorie rather than low-calorie stimuli. When controlling for age, gender, and BMI, larger high-calorie N2 difference amplitude predicted lower caloric intake (β = 0.17); low-calorie N2 difference amplitude was not related to caloric intake (β = -0.03). Exploratory analyses revealed larger high-calorie N2 difference amplitude predicted carbohydrate intake (β = 0.22), but not protein (β = 0.08) or fat (β = 0.11) intake. Results suggest that withholding responses from high-calorie foods requires increased recruitment of inhibitory control processes, which may be necessary to regulate food consumption, particularly for foods high in calories and carbohydrates. © 2017 Society for Psychophysiological Research.

Increased Early Processing of Task-Irrelevant Auditory Stimuli in Older Adults.

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Erich S Tusch

Full Text Available The inhibitory deficit hypothesis of cognitive aging posits that older adults' inability to adequately suppress processing of irrelevant information is a major source of cognitive decline. Prior research has demonstrated that in response to task-irrelevant auditory stimuli there is an age-associated increase in the amplitude of the N1 wave, an ERP marker of early perceptual processing. Here, we tested predictions derived from the inhibitory deficit hypothesis that the age-related increase in N1 would be 1 observed under an auditory-ignore, but not auditory-attend condition, 2 attenuated in individuals with high executive capacity (EC, and 3 augmented by increasing cognitive load of the primary visual task. ERPs were measured in 114 well-matched young, middle-aged, young-old, and old-old adults, designated as having high or average EC based on neuropsychological testing. Under the auditory-ignore (visual-attend task, participants ignored auditory stimuli and responded to rare target letters under low and high load. Under the auditory-attend task, participants ignored visual stimuli and responded to rare target tones. Results confirmed an age-associated increase in N1 amplitude to auditory stimuli under the auditory-ignore but not auditory-attend task. Contrary to predictions, EC did not modulate the N1 response. The load effect was the opposite of expectation: the N1 to task-irrelevant auditory events was smaller under high load. Finally, older adults did not simply fail to suppress the N1 to auditory stimuli in the task-irrelevant modality; they generated a larger response than to identical stimuli in the task-relevant modality. In summary, several of the study's findings do not fit the inhibitory-deficit hypothesis of cognitive aging, which may need to be refined or supplemented by alternative accounts.

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

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MAY, FRANK B.; TABACHNICK, B. ROBERT

THIS STUDY BEGAN AN ATTEMPT TO DETERMINE THE BASIC CHARACTERISTICS OF EFFECTIVE MOTIVATING STIMULI FOR USE IN ELEMENTARY SCHOOL WRITING PROGRAMS. IN PARTICULAR, IT DEALT WITH THE EFFECTS OF ORGANIZED AND UNORGANIZED STIMULI ON THE CREATIVE WRITING ABILITY OF THIRD- AND SIXTH-GRADE STUDENTS. THE CHILDREN WERE DIVIDED INTO SIX GROUPS. ONE GROUP OF…

Does the amygdala response correlate with the personality trait 'harm avoidance' while evaluating emotional stimuli explicitly?

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Van Schuerbeek, Peter; Baeken, Chris; Luypaert, Robert; De Raedt, Rudi; De Mey, Johan

2014-05-07

The affective personality trait 'harm avoidance' (HA) from Cloninger's psychobiological personality model determines how an individual deals with emotional stimuli. Emotional stimuli are processed by a neural network that include the left and right amygdalae as important key nodes. Explicit, implicit and passive processing of affective stimuli are known to activate the amygdalae differently reflecting differences in attention, level of detailed analysis of the stimuli and the cognitive control needed to perform the required task. Previous studies revealed that implicit processing or passive viewing of affective stimuli, induce a left amygdala response that correlates with HA. In this new study we have tried to extend these findings to the situation in which the subjects were required to explicitly process emotional stimuli. A group of healthy female participants was asked to rate the valence of positive and negative stimuli while undergoing fMRI. Afterwards the neural responses of the participants to the positive and to the negative stimuli were separately correlated to their HA scores and compared between the low and high HA participants. Both analyses revealed increased neural activity in the left laterobasal (LB) amygdala of the high HA participants while they were rating the positive and the negative stimuli. Our results indicate that the left amygdala response to explicit processing of affective stimuli does correlate with HA.

Generalized Habituation of Concept Stimuli in Toddlers

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Faulkender, Patricia J.; And Others

1974-01-01

An evaluation of selective generalization of habituation on the basis of meaningful categories of stimuli. Also explored are the sex differences in conceptual generalization of habituation. Subjects were 36 toddlers with a mean age of 40 months. (SDH)

Anxiety and autonomic response to social-affective stimuli in individuals with Williams syndrome.

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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.

Neural processing of food and emotional stimuli in adolescent and adult anorexia nervosa patients.

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Horndasch, Stefanie; Roesch, Julie; Forster, Clemens; Dörfler, Arnd; Lindsiepe, Silja; Heinrich, Hartmut; Graap, Holmer; Moll, Gunther H; Kratz, Oliver

2018-01-01

A constant preoccupation with food and restrictive eating are main symptoms of anorexia nervosa (AN). Imaging studies revealed aberrant neural activation patterns in brain regions processing hedonic and reward reactions as well as-potentially aversive-emotions. An imbalance between so called "bottom-up" and "top-down" control areas is discussed. The present study is focusing on neural processing of disease-specific food stimuli and emotional stimuli and its developmental course in adolescent and adult AN patients and could offer new insight into differential mechanisms underlying shorter or more chronic disease. 33 adolescents aged 12-18 years (15 AN patients, 18 control participants) and 32 adult women (16 AN patients, 16 control participants) underwent functional magnetic resonance imaging (fMRI, 3T high-field scanner) while watching pictures of high and low-calorie food and affective stimuli. Afterwards, they rated subjective valence of each picture. FMRI data analysis was performed using a region of interest based approach. Pictures of high-calorie food items were rated more negatively by AN patients. Differences in activation between patients and controls were found in "bottom up" and "top down" control areas for food stimuli and in several emotion processing regions for affective stimuli which were more pronounced in adolescents than in adults. A differential pattern was seen for food stimuli compared to generally emotion eliciting stimuli. Adolescents with AN show reduced processing of affective stimuli and enhanced activation of regions involved in "bottom up" reward processing and "top down" control as well as the insula with regard to food stimuli with a focus on brain regions which underlie changes during adolescent development. In adults less clear and less specific activation differences were present, pointing towards a high impact that regions undergoing maturation might have on AN symptoms.

Neural processing of food and emotional stimuli in adolescent and adult anorexia nervosa patients

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Forster, Clemens; Dörfler, Arnd; Lindsiepe, Silja; Heinrich, Hartmut; Graap, Holmer; Moll, Gunther H.; Kratz, Oliver

2018-01-01

Background A constant preoccupation with food and restrictive eating are main symptoms of anorexia nervosa (AN). Imaging studies revealed aberrant neural activation patterns in brain regions processing hedonic and reward reactions as well as–potentially aversive–emotions. An imbalance between so called “bottom-up” and “top-down” control areas is discussed. The present study is focusing on neural processing of disease-specific food stimuli and emotional stimuli and its developmental course in adolescent and adult AN patients and could offer new insight into differential mechanisms underlying shorter or more chronic disease. Methods 33 adolescents aged 12–18 years (15 AN patients, 18 control participants) and 32 adult women (16 AN patients, 16 control participants) underwent functional magnetic resonance imaging (fMRI, 3T high-field scanner) while watching pictures of high and low-calorie food and affective stimuli. Afterwards, they rated subjective valence of each picture. FMRI data analysis was performed using a region of interest based approach. Results Pictures of high-calorie food items were rated more negatively by AN patients. Differences in activation between patients and controls were found in “bottom up” and “top down” control areas for food stimuli and in several emotion processing regions for affective stimuli which were more pronounced in adolescents than in adults. Conclusion A differential pattern was seen for food stimuli compared to generally emotion eliciting stimuli. Adolescents with AN show reduced processing of affective stimuli and enhanced activation of regions involved in “bottom up” reward processing and “top down” control as well as the insula with regard to food stimuli with a focus on brain regions which underlie changes during adolescent development. In adults less clear and less specific activation differences were present, pointing towards a high impact that regions undergoing maturation might have on AN

Effects of hypnagogic imagery on the event-related potential to external tone stimuli.

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Michida, Nanae; Hayashi, Mitsuo; Hori, Tadao

2005-07-01

The purpose of this study was to examine the influence of hypnagogic imagery on the information processes of external tone stimuli during the sleep onset period with the use of event-related potentials. Event-related potentials to tone stimuli were compared between conditions with and without the experience of hypnagogic imagery. To control the arousal level when the tone was presented, a certain criterion named the electroencephalogram stage was used. Stimuli were presented at electroencephalogram stage 4, which was characterized by the appearance of a vertex sharp wave. Data were collected in the sleep laboratory at Hiroshima University. Eleven healthy university and graduate school students participated in the study. N/A. Experiments were performed at night. Reaction times to tone stimuli were measured, and only trials with shorter reaction times than 5000 milliseconds were analyzed. Electroencephalograms were recorded from Fz, Cz, Pz, Oz, T5 and T6. There were no differences in reaction times and electroencephalogram spectra between the conditions of with and without hypnagogic imagery. These results indicated that the arousal levels were not different between the 2 conditions. On the other hand, the N550 amplitude of the event-related potentials in the imagery condition was lower than in the no-imagery condition. The decrease in the N550 amplitude in the imagery condition showed that experiences of hypnagogic imagery exert some influence on the information processes of external tone stimuli. It is possible that the processing of hypnagogic imagery interferes with the processing of external stimuli, lowering the sensitivity to external stimuli.

Endogenous sequential cortical activity evoked by visual stimuli.

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

2015-06-10

Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. Copyright © 2015 Carrillo-Reid et al.

Associations between Tactile Sensory Threshold and Postural Performance and Effects of Healthy Aging and Subthreshold Vibrotactile Stimulation on Postural Outcomes in a Simple Dual Task

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Marius Dettmer

2016-01-01

Full Text Available Specific activities that require concurrent processing of postural and cognitive tasks may increase the risk for falls in older adults. We investigated whether peripheral receptor sensitivity was associated with postural performance in a dual-task and whether an intervention in form of subthreshold vibration could affect performance. Ten younger (age: 20–35 years and ten older adults (70–85 years performed repeated auditory-verbal 1-back tasks while standing quietly on a force platform. Foot sole vibration was randomly added during several trials. Several postural control and performance measures were assessed and statistically analyzed (significance set to α-levels of .05. There were moderate correlations between peripheral sensitivity and several postural performance and control measures (r=.45 to .59. Several postural performance measures differed significantly between older and younger adults (p<0.05; addition of vibration did not affect outcome measures. Aging affects healthy older adults’ performance in dual-tasks, and peripheral sensitivity may be a contributor to the observed differences. A vibration intervention may only be useful when there are more severe impairments of the sensorimotor system. Hence, future research regarding the efficacy of sensorimotor interventions in the form of vibrotactile stimulation should focus on older adults whose balance is significantly affected.

Attentional Bias for Emotional Stimuli in Borderline Personality Disorder: A Meta-Analysis.

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Kaiser, Deborah; Jacob, Gitta A; Domes, Gregor; Arntz, Arnoud

2016-01-01

In borderline personality disorder (BPD), attentional bias (AB) to emotional stimuli may be a core component in disorder pathogenesis and maintenance. 11 emotional Stroop task (EST) studies with 244 BPD patients, 255 nonpatients (NPs) and 95 clinical controls and 4 visual dot-probe task (VDPT) studies with 151 BPD patients or subjects with BPD features and 62 NPs were included. We conducted two separate meta-analyses for AB in BPD. One meta-analysis focused on the EST for generally negative and BPD-specific/personally relevant negative words. The other meta-analysis concentrated on the VDPT for negative and positive facial stimuli. There is evidence for an AB towards generally negative emotional words compared to NPs (standardized mean difference, SMD = 0.311) and to other psychiatric disorders (SMD = 0.374) in the EST studies. Regarding BPD-specific/personally relevant negative words, BPD patients reveal an even stronger AB than NPs (SMD = 0.454). The VDPT studies indicate a tendency towards an AB to positive facial stimuli but not negative stimuli in BPD patients compared to NPs. The findings rather reflect an AB in BPD to generally negative and BPD-specific/personally relevant negative words rather than an AB in BPD towards facial stimuli, and/or a biased allocation of covert attentional resources to negative emotional stimuli in BPD and not a bias in focus of visual attention. Further research regarding the role of childhood traumatization and comorbid anxiety disorders may improve the understanding of these underlying processes. © 2016 The Author(s) Published by S. Karger AG, Basel.

Negative emotional stimuli reduce contextual cueing but not response times in inefficient search

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Kunar, Melina A.; Watson, Derrick G.; Cole, Louise (Researcher in Psychology); Cox, Angeline

2014-01-01

In visual search, previous work has shown that negative stimuli narrow the focus of attention and speed reaction times (RTs). This paper investigates these two effects by first asking whether negative emotional stimuli narrow the focus of attention to reduce the learning of a display context in a contextual cueing task and, second, whether exposure to negative stimuli also reduces RTs in inefficient search tasks. In Experiment 1, participants viewed either negative or neutral images (faces or...

Brain response to visual sexual stimuli in homosexual pedophiles.

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

2008-01-01

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

Emotion regulation during the encoding of emotional stimuli: Effects on subsequent memory.

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Leventon, Jacqueline S; Bauer, Patricia J

2016-02-01

In the adult literature, emotional arousal is regarded as a source of the enhancing effect of emotion on subsequent memory. Here, we used behavioral and electrophysiological methods to examine the role of emotional arousal on subsequent memory in school-age children. Furthermore, we implemented a reappraisal instruction to manipulate (down-regulate) emotional arousal at encoding to examine the relation between emotional arousal and subsequent memory. Participants (8-year-old girls) viewed emotional scenes as electrophysiological (EEG) data were recorded and participated in a memory task 1 to 5days later where EEG and behavioral responses were recorded; participants provided subjective ratings of the scenes after the memory task. The reappraisal instruction successfully reduced emotional arousal responses to negative stimuli but not positive stimuli. Similarly, recognition performance in both event-related potentials (ERPs) and behavior was impaired for reappraised negative stimuli but not positive stimuli. The findings indicate that ERPs are sensitive to the reappraisal of negative stimuli in children as young as 8years. Furthermore, the findings suggest an interaction of emotion and memory during the school years, implicating the explanatory role of emotional arousal at encoding on subsequent memory performance in female children as young as 8years. Copyright © 2015 Elsevier Inc. All rights reserved.

Narcissism dimensions differentially moderate selective attention to evaluative stimuli in incarcerated offenders.

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Krusemark, Elizabeth A; Lee, Christopher; Newman, Joseph P

2015-01-01

Narcissistic personality disorder is associated with distinguishing traits including self-enhancement, arrogance, and intense reactivity to ego threat. Theoretical accounts of narcissism suggest these heterogeneous behaviors reflect a defensive motivational style that functions to both uphold and protect the self-concept. However, the notion that narcissism can be characterized by grandiose and vulnerable dimensions raises the possibility that these diverse behaviors represent distinct expressions of narcissistic defensiveness. The present study examined whether both dimensions exhibit a general defensive style marked by selective attention to evaluative stimuli or are differentially associated with selective attention to positive and negative information, respectively. Using a dot probe task consisting of valenced and neutral trait adjectives, we evaluated these hypotheses in a group of male offenders. Results indicated that vulnerable narcissism was associated with attention biases for both positive and negative stimuli, though the dimension was further distinguished by disengagement difficulties and a greater recognition memory bias in response to negative words. Conversely, grandiose narcissism was associated with increased accuracy when attending to positive stimuli and directing attention away from negative stimuli. Overall, these findings suggest narcissistic individuals share motivated selective attention in response to evaluative stimuli, while simultaneously highlighting important phenotypic differences between grandiose and vulnerable dimensions. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Affective and physiological correlates of the perception of unimodal and bimodal emotional stimuli.

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Rosa, Pedro J; Oliveira, Jorge; Alghazzawi, Daniyal; Fardoun, Habib; Gamito, Pedro

2017-08-01

Despite the multisensory nature of perception, previous research on emotions has been focused on unimodal emotional cues with visual stimuli. To the best of our knowledge, there is no evidence on the extent to which incongruent emotional cues from visual and auditory sensory channels affect pupil size. To investigate the effects of audiovisual emotional information perception on the physiological and affective response, but also to determine the impact of mismatched cues in emotional perception on these physiological indexes. Pupil size, electrodermal activity and affective subjective responses were recorded while 30 participants were exposed to visual and auditory stimuli with varied emotional content in three different experimental conditions: pictures and sounds presented alone (unimodal), emotionally matched audio-visual stimuli (bimodal congruent) and emotionally mismatched audio-visual stimuli (bimodal incongruent). The data revealed no effect of emotional incongruence on physiological and affective responses. On the other hand, pupil size covaried with skin conductance response (SCR), but the subjective experience was partially dissociated from autonomic responses. Emotional stimuli are able to trigger physiological responses regardless of valence, sensory modality or level of emotional congruence.

Read-out of emotional information from iconic memory: the longevity of threatening stimuli.

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Kuhbandner, Christof; Spitzer, Bernhard; Pekrun, Reinhard

2011-05-01

Previous research has shown that emotional stimuli are more likely than neutral stimuli to be selected by attention, indicating that the processing of emotional information is prioritized. In this study, we examined whether the emotional significance of stimuli influences visual processing already at the level of transient storage of incoming information in iconic memory, before attentional selection takes place. We used a typical iconic memory task in which the delay of a poststimulus cue, indicating which of several visual stimuli has to be reported, was varied. Performance decreased rapidly with increasing cue delay, reflecting the fast decay of information stored in iconic memory. However, although neutral stimulus information and emotional stimulus information were initially equally likely to enter iconic memory, the subsequent decay of the initially stored information was slowed for threatening stimuli, a result indicating that fear-relevant information has prolonged availability for read-out from iconic memory. This finding provides the first evidence that emotional significance already facilitates stimulus processing at the stage of iconic memory.

Monetary reward modulates task-irrelevant perceptual learning for invisible stimuli.

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Pascucci, David; Mastropasqua, Tommaso; Turatto, Massimo

2015-01-01

Task Irrelevant Perceptual Learning (TIPL) shows that the brain's discriminative capacity can improve also for invisible and unattended visual stimuli. It has been hypothesized that this form of "unconscious" neural plasticity is mediated by an endogenous reward mechanism triggered by the correct task performance. Although this result has challenged the mandatory role of attention in perceptual learning, no direct evidence exists of the hypothesized link between target recognition, reward and TIPL. Here, we manipulated the reward value associated with a target to demonstrate the involvement of reinforcement mechanisms in sensory plasticity for invisible inputs. Participants were trained in a central task associated with either high or low monetary incentives, provided only at the end of the experiment, while subliminal stimuli were presented peripherally. Our results showed that high incentive-value targets induced a greater degree of perceptual improvement for the subliminal stimuli, supporting the role of reinforcement mechanisms in TIPL.

Human-caused Disturbance Stimuli as a Form of Predation Risk

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Alejandro Frid

2002-06-01

Full Text Available A growing number of studies quantify the impact of nonlethal human disturbance on the behavior and reproductive success of animals. Athough many are well designed and analytically sophisticated, most lack a theoretical framework for making predictions and for understanding why particular responses occur. Behavioral ecologists have recently begun to fill this theoretical vacuum by applying economic models of antipredator behavior to disturbance studies. In this emerging paradigm, predation and nonlethal disturbance stimuli create similar trade-offs between avoiding perceived risk and other fitness-enhancing activities, such as feeding, parental care, or mating. A vast literature supports the hypothesis that antipredator behavior has a cost to other activities, and that this trade-off is optimized when investment in antipredator behavior tracks short-term changes in predation risk. Prey have evolved antipredator responses to generalized threatening stimuli, such as loud noises and rapidly approaching objects. Thus, when encountering disturbance stimuli ranging from the dramatic, low-flying helicopter to the quiet wildlife photographer, animal responses are likely to follow the same economic principles used by prey encountering predators. Some authors have argued that, similar to predation risk, disturbance stimuli can indirectly affect fitness and population dynamics via the energetic and lost opportunity costs of risk avoidance. We elaborate on this argument by discussing why, from an evolutionary perspective, disturbance stimuli should be analogous to predation risk. We then consider disturbance effects on the behavior of individuals - vigilance, fleeing, habitat selection, mating displays, and parental investment - as well as indirect effects on populations and communities. A wider application of predation risk theory to disturbance studies should increase the generality of predictions and make mitigation more effective without over

Usage of drip drops as stimuli in an auditory P300 BCI paradigm.

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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.

Investigating Deviance Distraction and the Impact of the Modality of the To-Be-Ignored Stimuli.

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Marsja, Erik; Neely, Gregory; Ljungberg, Jessica K

2018-03-01

It has been suggested that deviance distraction is caused by unexpected sensory events in the to-be-ignored stimuli violating the cognitive system's predictions of incoming stimuli. The majority of research has used methods where the to-be-ignored expected (standards) and the unexpected (deviants) stimuli are presented within the same modality. Less is known about the behavioral impact of deviance distraction when the to-be-ignored stimuli are presented in different modalities (e.g., standard and deviants presented in different modalities). In three experiments using cross-modal oddball tasks with mixed-modality to-be-ignored stimuli, we examined the distractive role of unexpected auditory deviants presented in a continuous stream of expected standard vibrations. The results showed that deviance distraction seems to be dependent upon the to-be-ignored stimuli being presented within the same modality, and that the simplest omission of something expected; in this case, a standard vibration may be enough to capture attention and distract performance.

Exploring the use of tactile feedback in an ERP-based auditory BCI.

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Schreuder, Martijn; Thurlings, Marieke E; Brouwer, Anne-Marie; Van Erp, Jan B F; Tangermann, Michael

2012-01-01

Giving direct, continuous feedback on a brain state is common practice in motor imagery based brain-computer interfaces (BCI), but has not been reported for BCIs based on event-related potentials (ERP), where feedback is only given once after a sequence of stimuli. Potentially, direct feedback could allow the user to adjust his strategy during a running trial to obtain the required response. In order to test the usefulness of such feedback, directionally congruent vibrotactile feedback was given during an online auditory BCI experiment. Users received either no feedback, short feedback pulses or continuous feedback. The feedback conditions showed reduced performance both on a behavioral task and in terms of classification accuracy. Several explanations are discussed that give interesting starting points for further research on this topic.

Effects of inter- and intramodal selective attention to non-spatial visual stimuli: An event-related potential analysis.

NARCIS (Netherlands)

de Ruiter, M.B.; Kok, A.; van der Schoot, M.

1998-01-01

Event-related potentials (ERPs) were recorded to trains of rapidly presented auditory and visual stimuli. ERPs in conditions in which Ss attended to different features of visual stimuli were compared with ERPs to the same type of stimuli when Ss attended to different features of auditory stimuli,

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

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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:…

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

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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…

Subliminal and supraliminal processing of reward-related stimuli in anorexia nervosa.

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Boehm, I; King, J A; Bernardoni, F; Geisler, D; Seidel, M; Ritschel, F; Goschke, T; Haynes, J-D; Roessner, V; Ehrlich, S

2018-04-01

Previous studies have highlighted the role of the brain reward and cognitive control systems in the etiology of anorexia nervosa (AN). In an attempt to disentangle the relative contribution of these systems to the disorder, we used functional magnetic resonance imaging (fMRI) to investigate hemodynamic responses to reward-related stimuli presented both subliminally and supraliminally in acutely underweight AN patients and age-matched healthy controls (HC). fMRI data were collected from a total of 35 AN patients and 35 HC, while they passively viewed subliminally and supraliminally presented streams of food, positive social, and neutral stimuli. Activation patterns of the group × stimulation condition × stimulus type interaction were interrogated to investigate potential group differences in processing different stimulus types under the two stimulation conditions. Moreover, changes in functional connectivity were investigated using generalized psychophysiological interaction analysis. AN patients showed a generally increased response to supraliminally presented stimuli in the inferior frontal junction (IFJ), but no alterations within the reward system. Increased activation during supraliminal stimulation with food stimuli was observed in the AN group in visual regions including superior occipital gyrus and the fusiform gyrus/parahippocampal gyrus. No group difference was found with respect to the subliminal stimulation condition and functional connectivity. Increased IFJ activation in AN during supraliminal stimulation may indicate hyperactive cognitive control, which resonates with clinical presentation of excessive self-control in AN patients. Increased activation to food stimuli in visual regions may be interpreted in light of an attentional food bias in AN.

Extinction of Conditioned Responses to Methamphetamine-Associated Stimuli in Healthy Humans.

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Cavallo, Joel S; Ruiz, Nicholas A; de Wit, Harriet

2016-07-01

Contextual stimuli present during drug experiences become associated with the drug through Pavlovian conditioning and are thought to sustain drug-seeking behavior. Thus, extinction of conditioned responses is an important target for treatment. To date, acquisition and extinction to drug-paired cues have been studied in animal models or drug-dependent individuals, but rarely in non-drug users. We have recently developed a procedure to study acquisition of conditioned responses after single doses of methamphetamine (MA) in healthy volunteers. Here, we examined extinction of these responses and their persistence after conditioning. Healthy adults (18-35 years; N = 20) received two pairings of audio-visual stimuli with MA (20 mg oral) or placebo. Responses to stimuli were assessed before and after conditioning, using three tasks: behavioral preference, attentional bias, and subjective "liking." Subjects exhibited behavioral preference for the drug-paired stimuli at the first post-conditioning test, but this declined rapidly on subsequent extinction tests. They also exhibited a bias to initially look towards the drug-paired stimuli at the first post-test session, but not thereafter. Subjects who experienced more positive subjective drug effects during conditioning exhibited a smaller decline in preference during the extinction phase. Further, longer inter-session intervals during the extinction phase were associated with less extinction of the behavioral preference measure. Conditioned responses after two pairings with MA extinguish quickly, and are influenced by both subjective drug effects and the extinction interval. Characterizing and refining this conditioning procedure will aid in understanding the acquisition and extinction processes of drug-related conditioned responses in humans.

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

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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

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

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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…

Response to various periods of mechanical stimuli in Physarum plasmodium

International Nuclear Information System (INIS)

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

2017-01-01

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. (paper)

Monetary reward modulates task-irrelevant perceptual learning for invisible stimuli.

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David Pascucci

Full Text Available Task Irrelevant Perceptual Learning (TIPL shows that the brain's discriminative capacity can improve also for invisible and unattended visual stimuli. It has been hypothesized that this form of "unconscious" neural plasticity is mediated by an endogenous reward mechanism triggered by the correct task performance. Although this result has challenged the mandatory role of attention in perceptual learning, no direct evidence exists of the hypothesized link between target recognition, reward and TIPL. Here, we manipulated the reward value associated with a target to demonstrate the involvement of reinforcement mechanisms in sensory plasticity for invisible inputs. Participants were trained in a central task associated with either high or low monetary incentives, provided only at the end of the experiment, while subliminal stimuli were presented peripherally. Our results showed that high incentive-value targets induced a greater degree of perceptual improvement for the subliminal stimuli, supporting the role of reinforcement mechanisms in TIPL.

Delivering Online Examinations: A Case Study

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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.

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

NARCIS (Netherlands)

Klink, P.C.; van Wezel, R.J.A.; van Ee, R.

2012-01-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

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

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Daniel de Zilva

Full Text Available 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.

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.

Absent Audiovisual Integration Elicited by Peripheral Stimuli in Parkinson’s Disease

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Yanna Ren

2018-01-01

Full Text Available The basal ganglia, which have been shown to be a significant multisensory hub, are disordered in Parkinson’s disease (PD. This study was to investigate the audiovisual integration of peripheral stimuli in PD patients with/without sleep disturbances. Thirty-six age-matched normal controls (NC and 30 PD patients were recruited for an auditory/visual discrimination experiment. The mean response times for each participant were analyzed using repeated measures ANOVA and race model. The results showed that the response to all stimuli was significantly delayed for PD compared to NC (all p0.05. The current results showed that audiovisual multisensory integration for peripheral stimuli is absent in PD regardless of sleep disturbances and further suggested the abnormal audiovisual integration might be a potential early manifestation of PD.

[Short-term memory characteristics of vibration intensity tactile perception on human wrist].

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Hao, Fei; Chen, Li-Juan; Lu, Wei; Song, Ai-Guo

2014-12-25

In this study, a recall experiment and a recognition experiment were designed to assess the human wrist's short-term memory characteristics of tactile perception on vibration intensity, by using a novel homemade vibrotactile display device based on the spatiotemporal combination vibration of multiple micro vibration motors as a test device. Based on the obtained experimental data, the short-term memory span, recognition accuracy and reaction time of vibration intensity were analyzed. From the experimental results, some important conclusions can be made: (1) The average short-term memory span of tactile perception on vibration intensity is 3 ± 1 items; (2) The greater difference between two adjacent discrete intensities of vibrotactile stimulation is defined, the better average short-term memory span human wrist gets; (3) There is an obvious difference of the average short-term memory span on vibration intensity between the male and female; (4) The mechanism of information extraction in short-term memory of vibrotactile display is to traverse the scanning process by comparison; (5) The recognition accuracy and reaction time performance of vibrotactile display compares unfavourably with that of visual and auditory. The results from this study are important for designing vibrotactile display coding scheme.

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

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

2014-01-01

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

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

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Asakawa, Tetsuya; Muramatsu, Ayumi; Hayashi, Takuto; Urata, Tatsuya; Taya, Masato; Mizuno-Matsumoto, Yuko

2014-01-01

The current study evaluated the effect of different anxiety states on information processing as measured by an electroencephalography (EEG) using emotional stimuli on a smartphone. Twenty-three healthy subjects were assessed for their anxiety states using The State Trait Anxiety Inventory (STAI) and divided into two groups: low anxiety (I, II) or high anxiety (III and IV, V). An EEG was performed while the participant was presented with emotionally laden audiovisual stimuli (resting, pleasant, and unpleasant sessions) and emotionally laden sentence stimuli (pleasant sentence, unpleasant sentence sessions) and EEG data was analyzed using propagation speed analysis. The propagation speed of the low anxiety group at the medial coronal for resting stimuli for all time segments was higher than those of high anxiety group. The low anxiety group propagation speeds at the medial sagittal for unpleasant stimuli in the 0–30 and 60–150 s time frames were higher than those of high anxiety group. The propagation speeds at 150 s for all stimuli in the low anxiety group were significantly higher than the correspondent propagation speeds of the high anxiety group. These events suggest that neural information processes concerning emotional stimuli differ based on current anxiety state. PMID:25540618

Hemispheric specialization in dogs for processing different acoustic stimuli.

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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.

The Commonality of Loss Aversion across Procedures and Stimuli.

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Lee, Sang; Lee, Myung J; Kim, Byoung W; Gilman, Jodi M; Kuster, John K; Blood, Anne J; Kuhnen, Camelia M; Breiter, Hans C

2015-01-01

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.

Decoding stimulus features in primate somatosensory cortex during perceptual categorization

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Alvarez, Manuel; Zainos, Antonio; Romo, Ranulfo

2015-01-01

Neurons of the primary somatosensory cortex (S1) respond as functions of frequency or amplitude of a vibrotactile stimulus. However, whether S1 neurons encode both frequency and amplitude of the vibrotactile stimulus or whether each sensory feature is encoded by separate populations of S1 neurons is not known, To further address these questions, we recorded S1 neurons while trained monkeys categorized only one sensory feature of the vibrotactile stimulus: frequency, amplitude, or duration. The results suggest a hierarchical encoding scheme in S1: from neurons that encode all sensory features of the vibrotactile stimulus to neurons that encode only one sensory feature. We hypothesize that the dynamic representation of each sensory feature in S1 might serve for further downstream processing that leads to the monkey’s psychophysical behavior observed in these tasks. PMID:25825711

Preparation of stimuli for timbre perception studies.

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Labuschagne, Ilse B; Hanekom, Johan J

2013-09-01

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

Are females more responsive to emotional stimuli? A neurophysiological study across arousal and valence dimensions.

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Lithari, C; Frantzidis, C A; Papadelis, C; Vivas, Ana B; Klados, M A; Kourtidou-Papadeli, C; Pappas, C; Ioannides, A A; Bamidis, P D

2010-03-01

Men and women seem to process emotions and react to them differently. Yet, few neurophysiological studies have systematically investigated gender differences in emotional processing. Here, we studied gender differences using Event Related Potentials (ERPs) and Skin Conductance Responses (SCR) recorded from participants who passively viewed emotional pictures selected from the International Affective Picture System (IAPS). The arousal and valence dimension of the stimuli were manipulated orthogonally. The peak amplitude and peak latency of ERP components and SCR were analyzed separately, and the scalp topographies of significant ERP differences were documented. Females responded with enhanced negative components (N100 and N200), in comparison to males, especially to the unpleasant visual stimuli, whereas both genders responded faster to high arousing or unpleasant stimuli. Scalp topographies revealed more pronounced gender differences on central and left hemisphere areas. Our results suggest a difference in the way emotional stimuli are processed by genders: unpleasant and high arousing stimuli evoke greater ERP amplitudes in women relatively to men. It also seems that unpleasant or high arousing stimuli are temporally prioritized during visual processing by both genders.

How stimuli presentation format affects visual attention and choice outcomes in choice experiments

DEFF Research Database (Denmark)

Orquin, Jacob Lund; Mueller Loose, Simone

This study analyses visual attention and part-worth utilities in choice experiments across three different choice stimuli presentation formats. Visual attention and choice behaviour in discrete choice experiments are found to be strongly affected by stimuli presentation format. These results...

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)

Positive erotic picture stimuli for emotion research in heterosexual females.

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

2011-12-30

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

Learning efficient visual search for stimuli containing diagnostic spatial configurations and color-shape conjunctions.

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Reavis, Eric A; Frank, Sebastian M; Tse, Peter U

2018-04-12

Visual search is often slow and difficult for complex stimuli such as feature conjunctions. Search efficiency, however, can improve with training. Search for stimuli that can be identified by the spatial configuration of two elements (e.g., the relative position of two colored shapes) improves dramatically within a few hundred trials of practice. Several recent imaging studies have identified neural correlates of this learning, but it remains unclear what stimulus properties participants learn to use to search efficiently. Influential models, such as reverse hierarchy theory, propose two major possibilities: learning to use information contained in low-level image statistics (e.g., single features at particular retinotopic locations) or in high-level characteristics (e.g., feature conjunctions) of the task-relevant stimuli. In a series of experiments, we tested these two hypotheses, which make different predictions about the effect of various stimulus manipulations after training. We find relatively small effects of manipulating low-level properties of the stimuli (e.g., changing their retinotopic location) and some conjunctive properties (e.g., color-position), whereas the effects of manipulating other conjunctive properties (e.g., color-shape) are larger. Overall, the findings suggest conjunction learning involving such stimuli might be an emergent phenomenon that reflects multiple different learning processes, each of which capitalizes on different types of information contained in the stimuli. We also show that both targets and distractors are learned, and that reversing learned target and distractor identities impairs performance. This suggests that participants do not merely learn to discriminate target and distractor stimuli, they also learn stimulus identity mappings that contribute to performance improvements.

Perception of non-verbal auditory stimuli in Italian dyslexic children.

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Cantiani, Chiara; Lorusso, Maria Luisa; Valnegri, Camilla; Molteni, Massimo

2010-01-01

Auditory temporal processing deficits have been proposed as the underlying cause of phonological difficulties in Developmental Dyslexia. The hypothesis was tested in a sample of 20 Italian dyslexic children aged 8-14, and 20 matched control children. Three tasks of auditory processing of non-verbal stimuli, involving discrimination and reproduction of sequences of rapidly presented short sounds were expressly created. Dyslexic subjects performed more poorly than control children, suggesting the presence of a deficit only partially influenced by the duration of the stimuli and of inter-stimulus intervals (ISIs).

Adding stimuli-responsive extensions to antifouling hairy particles

NARCIS (Netherlands)

Munoz Bonilla, Sandra; Herk, van A.M.; Heuts, J.P.A.

2010-01-01

The use of living block copolymers as stabilisers in emulsion polymerisation allowed preparation of multilayer functional hairy particles via surface-initiated ATRP. Polymer films prepared from the obtained particles present antifouling properties along with stimuli-responsive behaviour.

Ideological reactivity: Political conservatism and brain responsivity to emotional and neutral stimuli.

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Tritt, Shona M; Peterson, Jordan B; Page-Gould, Elizabeth; Inzlicht, Michael

2016-12-01

Conservatives are often thought to have a negativity bias-responding more intensely to negative than positive information. Yet, recent research has found that greater endorsement of conservative beliefs follows from both positive and negative emotion inductions. This suggests that the role of affect in political thought may not be restricted to negative valence, and more attention should be given to how conservatives and liberals respond to a wider range of stimulation. In this vein, we examined neural responses to a full range of affective stimuli, allowing us to examine how self-reported ideology moderated these responses. Specifically, we explored the relationship between political orientation and 2 event-related potentials (1 late and 1 early) previously shown to covary with the subjective motivational salience of stimuli-in response to photographs with standardized ratings of arousal and valence. At late time points, conservatives exhibited sustained heightened reactivity, compared with liberals, specifically in response to relatively unarousing and neutral stimuli. At early time points, conservatives exhibited somewhat enhanced neural activity in response to all stimulus types compared with liberals. These results may suggest that conservatives experience a wide variety of stimuli in their environment with increased motivational salience, including positive, neutral, and low-arousal stimuli. No effects of valence were found in this investigation. Such findings have implications for the development and refinement of psychological conceptions of political orientation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Background music genre can modulate flavor pleasantness and overall impression of food stimuli.

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Fiegel, Alexandra; Meullenet, Jean-François; Harrington, Robert J; Humble, Rachel; Seo, Han-Seok

2014-05-01

This study aimed to determine whether background music genre can alter food perception and acceptance, but also to determine how the effect of background music can vary as a function of type of food (emotional versus non-emotional foods) and source of music performer (single versus multiple performers). The music piece was edited into four genres: classical, jazz, hip-hop, and rock, by either a single or multiple performers. Following consumption of emotional (milk chocolate) or non-emotional food (bell peppers) with the four musical stimuli, participants were asked to rate sensory perception and impression of food stimuli. Participants liked food stimuli significantly more while listening to the jazz stimulus than the hip-hop stimulus. Further, the influence of background music on overall impression was present in the emotional food, but not in the non-emotional food. In addition, flavor pleasantness and overall impression of food stimuli differed between music genres arranged by a single performer, but not between those by multiple performers. In conclusion, our findings demonstrate that music genre can alter flavor pleasantness and overall impression of food stimuli. Furthermore, the influence of music genre on food acceptance varies as a function of the type of served food and the source of music performer. Published by Elsevier Ltd.

Differences in male and female subjective experience and physiological reactions to emotional stimuli.

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Poláčková Šolcová, Iva; Lačev, Alek

2017-07-01

Research based on self-reported data often indicates that women are the more emotional sex. The present study examined differences in emotion between the sexes across two components of the emotional process: subjective experience and physiological reactions to emotional stimuli. During the experimental study, participants (N=124; 22.5±2.88; 51 males) subjectively rated their emotional experience (valence and intensity) towards presented positive and negative affective stimuli, while physiological reactions (facial electromyography, heart rate, skin conductance, and finger skin temperature) were measured during expositions. Results from self-reports suggest that women declared more intensive emotional experiences for positive and negative stimuli and rated negative stimuli as more negative in comparison to men. Physiological measurements showed differences between the sexes in the physiological baseline measurements (facial electromyography, skin conductance and finger skin temperature). However, physiological responses towards positive or negative emotional stimuli did not prove to be different between men and women, except for finger skin temperature. Relations between self-reported subjective experiences and physiological changes were weak and insignificant. Collectively, our findings suggest certain emotional differences experienced between men and women. These differences can be found specifically in self-reported subjective experiences, while significant differences were not predominantly present in recorded physiological reactions. Copyright © 2017. Published by Elsevier B.V.

Implicit attitudes toward eating stimuli differentiate eating disorder and non-eating disorder groups and predict eating disorder behaviors.

Science.gov (United States)

Smith, April R; Forrest, Lauren N; Velkoff, Elizabeth A; Ribeiro, Jessica D; Franklin, Joseph

2018-04-01

The current study tested whether people with and without eating disorders (EDs) varied in their implicit attitudes toward ED-relevant stimuli. Additionally, the study tested whether implicit evaluations of ED-relevant stimuli predicted ED symptoms and behaviors over a 4-week interval. Participants were people without EDs (N = 85) and people seeking treatment for EDs (N = 92). All participants completed self-report questionnaires and a version of the affect misattribution procedure (AMP) at baseline. The AMP indexed implicit evaluations of average body stimuli, eating stimuli, and ED-symptom stimuli. Participants with EDs completed weekly follow-up measures of ED symptoms and behaviors for 4 weeks. Contrary to predictions, the anorexia nervosa (AN) group did not differ from the no ED group on implicit attitudes toward ED-symptom stimuli, and the bulimia nervosa (BN) group had less positive implicit attitudes toward ED-symptom stimuli relative to the no ED group. In line with predictions, people with AN and BN had more negative implicit attitudes toward average body and eating stimuli relative to the no ED group. In addition, among the ED group more negative implicit attitudes toward eating stimuli predicted ED symptoms and behaviors 4 weeks later, over and above baseline ED symptoms and behaviors. Taken together, implicit evaluations of eating stimuli differentiated people with AN and BN from people without EDs and longitudinally predicted ED symptoms and behaviors. Interventions that increase implicit liking of eating-related stimuli may reduce ED behaviors. © 2018 Wiley Periodicals, Inc.

Preserved suppression of salient irrelevant stimuli during visual search in Age-Associated Memory Impairment

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Laura eLorenzo-López

2016-01-01

Full Text Available Previous studies have suggested that older adults with age-associated memory impairment (AAMI may show a significant decline in attentional resource capacity and inhibitory processes in addition to memory impairment. In the present paper, the potential attentional capture by task-irrelevant stimuli was examined in older adults with AAMI compared to healthy older adults using scalp-recorded event-related brain potentials (ERPs. ERPs were recorded during the execution of a visual search task, in which the participants had to detect the presence of a target stimulus that differed from distractors by orientation. To explore the automatic attentional capture phenomenon, an irrelevant distractor stimulus defined by a different feature (color was also presented without previous knowledge of the participants. A consistent N2pc, an electrophysiological indicator of attentional deployment, was present for target stimuli but not for task-irrelevant color stimuli, suggesting that these irrelevant distractors did not attract attention in AAMI older adults. Furthermore, the N2pc for targets was significantly delayed in AAMI patients compared to healthy older controls. Together, these findings suggest a specific impairment of the attentional selection process of relevant target stimuli in these individuals and indicate that the mechanism of top-down suppression of entirely task-irrelevant stimuli is preserved, at least when the target and the irrelevant stimuli are perceptually very different.

Diffuse optical tomography activation in the somatosensory cortex: specific activation by painful vs. non-painful thermal stimuli.

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Lino Becerra

2009-11-01

Full Text Available Pain is difficult to assess due to the subjective nature of self-reporting. The lack of objective measures of pain has hampered the development of new treatments as well as the evaluation of current ones. Functional MRI studies of pain have begun to delineate potential brain response signatures that could be used as objective read-outs of pain. Using Diffuse Optical Tomography (DOT, we have shown in the past a distinct DOT signal over the somatosensory cortex to a noxious heat stimulus that could be distinguished from the signal elicited by innocuous mechanical stimuli. Here we further our findings by studying the response to thermal innocuous and noxious stimuli.Innocuous and noxious thermal stimuli were applied to the skin of the face of the first division (ophthalmic of the trigeminal nerve in healthy volunteers (N = 6. Stimuli temperatures were adjusted for each subject to evoke warm (equivalent to a 3/10 and painful hot (7/10 sensations in a verbal rating scale (0/10 = no/max pain. A set of 26 stimuli (5 sec each was applied for each temperature with inter-stimulus intervals varied between 8 and 15 sec using a Peltier thermode. A DOT system was used to capture cortical responses on both sides of the head over the primary somatosensory cortical region (S1. For the innocuous stimuli, group results indicated mainly activation on the contralateral side with a weak ipsilateral response. For the noxious stimuli, bilateral activation was observed with comparable amplitudes on both sides. Furthermore, noxious stimuli produced a temporal biphasic response while innocuous stimuli produced a monophasic response.These results are in accordance with fMRI and our other DOT studies of innocuous mechanical and noxious heat stimuli. The data indicate the differentiation of DOT cortical responses for pain vs. innocuous stimuli that may be useful in assessing objectively acute pain.

Shape Memory Investigation of α-Keratin Fibers as Multi-Coupled Stimuli of Responsive Smart Materials

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Xueliang Xiao

2017-03-01

Full Text Available Like the water responsive shape memory (SM effect of β-keratin bird feathers, α-keratin hairs either existing broadly in nature are found responsive to many types of coupled stimuli in SM behaviors. In this article, α-keratin hairs were investigated for the combined stimuli of thermo-solvent, solvent-solvent, and UV (radiation-reductant sensitive SM abilities. The related netpoints and switches from the hair molecular networks were identified. The experimental results showed that α-keratin hairs manifested a higher ability of shape fixation under thermal stimulus followed with the stimuli of solvent and UV-radiation. Shape recovery from the hair with a temporarily fixed shape showed a higher recovery ability using solvent than the stimuli of heat and UV-radiation. The effects of coupled stimuli on hair’s shape fixation and recovery and on variations of the crystal, disulfide, and hydrogen bonds were studied systematically. A structural network model was thereafter proposed to interpret the multi-coupled stimuli sensitive SM of α-keratin hair. This original study is expected to provide inspiration for exploring other natural fibers to reveal related smart functions and for making more types of remarkable adapted synthetic materials.

The Potential of Stimuli-Responsive Nanogels in Drug and Active Molecule Delivery for Targeted Therapy

Directory of Open Access Journals (Sweden)

Marta Vicario-de-la-Torre

2017-05-01

Full Text Available Nanogels (NGs are currently under extensive investigation due to their unique properties, such as small particle size, high encapsulation efficiency and protection of active agents from degradation, which make them ideal candidates as drug delivery systems (DDS. Stimuli-responsive NGs are cross-linked nanoparticles (NPs, composed of polymers, natural, synthetic, or a combination thereof that can swell by absorption (uptake of large amounts of solvent, but not dissolve due to the constituent structure of the polymeric network. NGs can undergo change from a polymeric solution (swell form to a hard particle (collapsed form in response to (i physical stimuli such as temperature, ionic strength, magnetic or electric fields; (ii chemical stimuli such as pH, ions, specific molecules or (iii biochemical stimuli such as enzymatic substrates or affinity ligands. The interest in NGs comes from their multi-stimuli nature involving reversible phase transitions in response to changes in the external media in a faster way than macroscopic gels or hydrogels due to their nanometric size. NGs have a porous structure able to encapsulate small molecules such as drugs and genes, then releasing them by changing their volume when external stimuli are applied.

Fabrication of stimuli-sensitive hydrogel for the removal of cesium

Energy Technology Data Exchange (ETDEWEB)

Yang, Hee-Man; Bong, Sang Bum; Park, Chan Woo; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment.1 Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. 2 Various surface including road, roof, house, building were contaminated with Cs-137. These coating materials have some problems and limitation such as toxic component, and lack of reusability of materials related to the cost. Thus, a more cost-effective and environmental friendly coating materials is still desired. 3 In the present study, the stimuli-sensitive hydrogel were fabricated for the removal of radioactive Cs from solid surface. We describe the morphology, structure, and physical property of these stimuli sensitive hydrogel. In addition, their ability to eliminate cesium was also evaluated. The smart hydrogel coating materials showed an excellent morphology change from the liquid to film by addition of Ca ion. Therefore, the stimuli-sensitive hydrogel demonstrated good potential for the treatment of contaminated surface for the removal of radioactive cesium.

Fabrication of stimuli-sensitive hydrogel for the removal of cesium

International Nuclear Information System (INIS)

Yang, Hee-Man; Bong, Sang Bum; Park, Chan Woo; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon

2015-01-01

The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment.1 Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. 2 Various surface including road, roof, house, building were contaminated with Cs-137. These coating materials have some problems and limitation such as toxic component, and lack of reusability of materials related to the cost. Thus, a more cost-effective and environmental friendly coating materials is still desired. 3 In the present study, the stimuli-sensitive hydrogel were fabricated for the removal of radioactive Cs from solid surface. We describe the morphology, structure, and physical property of these stimuli sensitive hydrogel. In addition, their ability to eliminate cesium was also evaluated. The smart hydrogel coating materials showed an excellent morphology change from the liquid to film by addition of Ca ion. Therefore, the stimuli-sensitive hydrogel demonstrated good potential for the treatment of contaminated surface for the removal of radioactive cesium

A leptin-regulated circuit controls glucose mobilization during noxious stimuli.

Science.gov (United States)

Flak, Jonathan N; Arble, Deanna; Pan, Warren; Patterson, Christa; Lanigan, Thomas; Goforth, Paulette B; Sacksner, Jamie; Joosten, Maja; Morgan, Donald A; Allison, Margaret B; Hayes, John; Feldman, Eva; Seeley, Randy J; Olson, David P; Rahmouni, Kamal; Myers, Martin G

2017-08-01

Adipocytes secrete the hormone leptin to signal the sufficiency of energy stores. Reductions in circulating leptin concentrations reflect a negative energy balance, which augments sympathetic nervous system (SNS) activation in response to metabolically demanding emergencies. This process ensures adequate glucose mobilization despite low energy stores. We report that leptin receptor-expressing neurons (LepRb neurons) in the periaqueductal gray (PAG), the largest population of LepRb neurons in the brain stem, mediate this process. Application of noxious stimuli, which often signal the need to mobilize glucose to support an appropriate response, activated PAG LepRb neurons, which project to and activate parabrachial nucleus (PBN) neurons that control SNS activation and glucose mobilization. Furthermore, activating PAG LepRb neurons increased SNS activity and blood glucose concentrations, while ablating LepRb in PAG neurons augmented glucose mobilization in response to noxious stimuli. Thus, decreased leptin action on PAG LepRb neurons augments the autonomic response to noxious stimuli, ensuring sufficient glucose mobilization during periods of acute demand in the face of diminished energy stores.

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

Directory of Open Access Journals (Sweden)

Yuanqing Li

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

A study on stress stimuli among the students of physical education

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J.P.VERMA

2011-04-01

Full Text Available The present study was undertaken to study the stress level of physical education students in auniversity. Level of stress due to different stimuli and level of coping strategy of men and women weremeasured by using the questionnaire. Thirty male and thirty female physical education students were randomlyselected. Stress scores due to 1.Frustration and Inhibition, 2. Overload and 3.Compulsive, Time-urgent andAggression were recorded for each student using the questionnaire. These subjects were also tested for theirlevel of coping strategy. Scores obtained were analyzed using SPSS version 16.0. The results showed that thefrustration and inhibition had significant correlation with time-urgent and aggressive stimuli in the PG menwhereas, there was significant correlation between frustration and inhibition v/s overload stimuli among UGmen. Similarly in the UG and PG women there was a significant correlation between frustration and inhibitionv/s overload. Further, in PG women there was a negative relation between coping strategy and stress due totime-urgent and aggressive stimuli.Further, two way analysis of variance resulted that stress due to all the three stimuli i.e. frustration andinhibition (p=.003, overload (p=.049 and time-urgent and aggressive behavior (p=.042 were significantlyhigher among women in comparison to that of men irrespective of their classes. Whereas coping strategy(p=.048 was higher in men in comparison to that of women. In assessing the vulnerability towards stress it wasobserved that among the UG section 86.7% men were vulnerable to stress due to frustration and inhibitionwhereas 100% women were found to be vulnerable to the stress due to overload. In PG section 80% men werevulnerable to stress due to overload whereas 100% women were found to be vulnerable to stress due to timeurgent and aggressive behavior. In the UG section 80% men and 60% women were having adequate or goodcoping strategies whereas in PG section 80% men and

Attention modulates the dorsal striatum response to love stimuli.

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

2014-02-01

In previous functional magnetic resonance imaging (fMRI) studies concerning romantic love, several brain regions including the caudate and putamen have consistently been found to be more responsive to beloved-related than control stimuli. In those studies, infatuated individuals were typically instructed to passively view the stimuli or to think of the viewed person. In the current study, we examined how the instruction to attend to, or ignore the beloved modulates the response of these brain areas. Infatuated individuals performed an oddball task in which pictures of their beloved and friend served as targets and distractors. The dorsal striatum showed greater activation for the beloved than friend, but only when they were targets. The dorsal striatum actually tended to show less activation for the beloved than the friend when they were distractors. The longer the love and relationship duration, the smaller the response of the dorsal striatum to beloved-distractor stimuli was. We interpret our findings in terms of reinforcement learning. By virtue of using a cognitive task with a full factorial design, we show that the dorsal striatum is not activated by beloved-related information per se, but only by beloved-related information that is attended. Copyright © 2012 Wiley Periodicals, Inc.

The Commonality of Loss Aversion across Procedures and Stimuli

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Kim, Byoung W.; Gilman, Jodi M.; Kuster, John K.; Blood, Anne J.; Kuhnen, Camelia M.

2015-01-01

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. PMID:26394306

The Commonality of Loss Aversion across Procedures and Stimuli.

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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.

Data Collection and Analysis Techniques for Evaluating the Perceptual Qualities of Auditory Stimuli

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Bonebright, T.L.; Caudell, T.P.; Goldsmith, T.E.; Miner, N.E.

1998-11-17

This paper describes a general methodological framework for evaluating the perceptual properties of auditory stimuli. The framework provides analysis techniques that can ensure the effective use of sound for a variety of applications including virtual reality and data sonification systems. Specifically, we discuss data collection techniques for the perceptual qualities of single auditory stimuli including identification tasks, context-based ratings, and attribute ratings. In addition, we present methods for comparing auditory stimuli, such as discrimination tasks, similarity ratings, and sorting tasks. Finally, we discuss statistical techniques that focus on the perceptual relations among stimuli, such as Multidimensional Scaling (MDS) and Pathfinder Analysis. These methods are presented as a starting point for an organized and systematic approach for non-experts in perceptual experimental methods, rather than as a complete manual for performing the statistical techniques and data collection methods. It is our hope that this paper will help foster further interdisciplinary collaboration among perceptual researchers, designers, engineers, and others in the development of effective auditory displays.

Beyond arousal and valence: the importance of the biological versus social relevance of emotional stimuli

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Sakaki, Michiko; Niki, N.; Mather, M.

2012-01-01

The present study addressed the hypothesis that emotional stimuli relevant to survival or reproduction (biologically emotional stimuli) automatically affect cognitive processing (e.g., attention, memory), while those relevant to social life (socially emotional stimuli) require elaborative processing to modulate attention and memory. Results of our behavioral studies showed that (1) biologically emotional images hold attention more strongly than do socially emotional images, (2) memory for bio...

Network evolution induced by asynchronous stimuli through spike-timing-dependent plasticity.

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Wu-Jie Yuan

Full Text Available In sensory neural system, external asynchronous stimuli play an important role in perceptual learning, associative memory and map development. However, the organization of structure and dynamics of neural networks induced by external asynchronous stimuli are not well understood. Spike-timing-dependent plasticity (STDP is a typical synaptic plasticity that has been extensively found in the sensory systems and that has received much theoretical attention. This synaptic plasticity is highly sensitive to correlations between pre- and postsynaptic firings. Thus, STDP is expected to play an important role in response to external asynchronous stimuli, which can induce segregative pre- and postsynaptic firings. In this paper, we study the impact of external asynchronous stimuli on the organization of structure and dynamics of neural networks through STDP. We construct a two-dimensional spatial neural network model with local connectivity and sparseness, and use external currents to stimulate alternately on different spatial layers. The adopted external currents imposed alternately on spatial layers can be here regarded as external asynchronous stimuli. Through extensive numerical simulations, we focus on the effects of stimulus number and inter-stimulus timing on synaptic connecting weights and the property of propagation dynamics in the resulting network structure. Interestingly, the resulting feedforward structure induced by stimulus-dependent asynchronous firings and its propagation dynamics reflect both the underlying property of STDP. The results imply a possible important role of STDP in generating feedforward structure and collective propagation activity required for experience-dependent map plasticity in developing in vivo sensory pathways and cortices. The relevance of the results to cue-triggered recall of learned temporal sequences, an important cognitive function, is briefly discussed as well. Furthermore, this finding suggests a potential

Common brain activations for painful and non-painful aversive stimuli

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Hayes Dave J

2012-06-01

Full Text Available Abstract Background Identification of potentially harmful stimuli is necessary for the well-being and self-preservation of all organisms. However, the neural substrates involved in the processing of aversive stimuli are not well understood. For instance, painful and non-painful aversive stimuli are largely thought to activate different neural networks. However, it is presently unclear whether there is a common aversion-related network of brain regions responsible for the basic processing of aversive stimuli. To help clarify this issue, this report used a cross-species translational approach in humans (i.e. meta-analysis and rodents (i.e. systematic review of functional neuroanatomy. Results Animal and human data combined to show a core aversion-related network, consisting of similar cortical (i.e. MCC, PCC, AI, DMPFC, RTG, SMA, VLOFC; see results section or abbreviation section for full names and subcortical (i.e. Amyg, BNST, DS, Hab, Hipp/Parahipp, Hyp, NAc, NTS, PAG, PBN, raphe, septal nuclei, Thal, LC, midbrain regions. In addition, a number of regions appeared to be more involved in pain-related (e.g. sensory cortex or non-pain-related (e.g. amygdala aversive processing. Conclusions This investigation suggests that aversive processing, at the most basic level, relies on similar neural substrates, and that differential responses may be due, in part, to the recruitment of additional structures as well as the spatio-temporal dynamic activity of the network. This network perspective may provide a clearer understanding of why components of this circuit appear dysfunctional in some psychiatric and pain-related disorders.

North-American norms for name disagreement: pictorial stimuli naming discrepancies.

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Mary O'Sullivan

Full Text Available Pictorial stimuli are commonly used by scientists to explore central processes; including memory, attention, and language. Pictures that have been collected and put into sets for these purposes often contain visual ambiguities that lead to name disagreement amongst subjects. In the present work, we propose new norms which reflect these sources of name disagreement, and we apply this method to two sets of pictures: the Snodgrass and Vanderwart (S&V set and the Bank of Standardized Stimuli (BOSS. Naming responses of the presented pictures were classified within response categories based on whether they were correct, incorrect, or equivocal. To characterize the naming strategy where an alternative name was being used, responses were further divided into different sub-categories that reflected various sources of name disagreement. Naming strategies were also compared across the two sets of stimuli. Results showed that the pictures of the S&V set and the BOSS were more likely to elicit alternative specific and equivocal names, respectively. It was also found that the use of incorrect names was not significantly different across stimulus sets but that errors were more likely caused by visual ambiguity in the S&V set and by a misuse of names in the BOSS. Norms for name disagreement presented in this paper are useful for subsequent research for their categorization and elucidation of name disagreement that occurs when choosing visual stimuli from one or both stimulus sets. The sources of disagreement should be examined carefully as they help to provide an explanation of errors and inconsistencies of many concepts during picture naming tasks.

Feedback and feedforward control of frequency tuning to naturalistic stimuli.

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

2005-06-08

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

Neural activation toward erotic stimuli in homosexual and heterosexual males.

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

2011-11-01

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

Development of degradable renewable polymers and stimuli-responsive nanocomposites

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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

Delivering high performance BWR fuel reliably

International Nuclear Information System (INIS)

Schardt, J.F.

1998-01-01

Utilities are under intense pressure to reduce their production costs in order to compete in the increasingly deregulated marketplace. They need fuel, which can deliver high performance to meet demanding operating strategies. GE's latest BWR fuel design, GE14, provides that high performance capability. GE's product introduction process assures that this performance will be delivered reliably, with little risk to the utility. (author)

Audiovisual Capture with Ambiguous Audiovisual Stimuli

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Jean-Michel Hupé

2011-10-01

Full Text Available Audiovisual capture happens when information across modalities get fused into a coherent percept. Ambiguous multi-modal stimuli have the potential to be powerful tools to observe such effects. We used such stimuli made of temporally synchronized and spatially co-localized visual flashes and auditory tones. The flashes produced bistable apparent motion and the tones produced ambiguous streaming. We measured strong interferences between perceptual decisions in each modality, a case of audiovisual capture. However, does this mean that audiovisual capture occurs before bistable decision? We argue that this is not the case, as the interference had a slow temporal dynamics and was modulated by audiovisual congruence, suggestive of high-level factors such as attention or intention. We propose a framework to integrate bistability and audiovisual capture, which distinguishes between “what” competes and “how” it competes (Hupé et al., 2008. The audiovisual interactions may be the result of contextual influences on neural representations (“what” competes, quite independent from the causal mechanisms of perceptual switches (“how” it competes. This framework predicts that audiovisual capture can bias bistability especially if modalities are congruent (Sato et al., 2007, but that is fundamentally distinct in nature from the bistable competition mechanism.

Spatiotemporal Relationships among Audiovisual Stimuli Modulate Auditory Facilitation of Visual Target Discrimination.

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Li, Qi; Yang, Huamin; Sun, Fang; Wu, Jinglong

2015-03-01

Sensory information is multimodal; through audiovisual interaction, task-irrelevant auditory stimuli tend to speed response times and increase visual perception accuracy. However, mechanisms underlying these performance enhancements have remained unclear. We hypothesize that task-irrelevant auditory stimuli might provide reliable temporal and spatial cues for visual target discrimination and behavioral response enhancement. Using signal detection theory, the present study investigated the effects of spatiotemporal relationships on auditory facilitation of visual target discrimination. Three experiments were conducted where an auditory stimulus maintained reliable temporal and/or spatial relationships with visual target stimuli. Results showed that perception sensitivity (d') to visual target stimuli was enhanced only when a task-irrelevant auditory stimulus maintained reliable spatiotemporal relationships with a visual target stimulus. When only reliable spatial or temporal information was contained, perception sensitivity was not enhanced. These results suggest that reliable spatiotemporal relationships between visual and auditory signals are required for audiovisual integration during a visual discrimination task, most likely due to a spread of attention. These results also indicate that auditory facilitation of visual target discrimination follows from late-stage cognitive processes rather than early stage sensory processes. © 2015 SAGE Publications.

In Situ Cross-Linking of Stimuli-Responsive Hemicellulose Microgels during Spray Drying

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2015-01-01

Chemical cross-linking during spray drying offers the potential for green fabrication of microgels with a rapid stimuli response and good blood compatibility and provides a platform for stimuli-responsive hemicellulose microgels (SRHMGs). The cross-linking reaction occurs rapidly in situ at elevated temperature during spray drying, enabling the production of microgels in a large scale within a few minutes. The SRHMGs with an average size range of ∼1–4 μm contain O-acetyl-galactoglucomannan as a matrix and poly(acrylic acid), aniline pentamer (AP), and iron as functional additives, which are responsive to external changes in pH, electrochemical stimuli, magnetic field, or dual-stimuli. The surface morphologies, chemical compositions, charge, pH, and mechanical properties of these smart microgels were evaluated using scanning electron microscopy, IR, zeta potential measurements, pH evaluation, and quantitative nanomechanical mapping, respectively. Different oxidation states were observed when AP was introduced, as confirmed by UV spectroscopy and cyclic voltammetry. Systematic blood compatibility evaluations revealed that the SRHMGs have good blood compatibility. This bottom-up strategy to synthesize SRHMGs enables a new route to the production of smart microgels for biomedical applications. PMID:25630464

In situ cross-linking of stimuli-responsive hemicellulose microgels during spray drying.

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Zhao, Weifeng; Nugroho, Robertus Wahyu N; Odelius, Karin; Edlund, Ulrica; Zhao, Changsheng; Albertsson, Ann-Christine

2015-02-25

Chemical cross-linking during spray drying offers the potential for green fabrication of microgels with a rapid stimuli response and good blood compatibility and provides a platform for stimuli-responsive hemicellulose microgels (SRHMGs). The cross-linking reaction occurs rapidly in situ at elevated temperature during spray drying, enabling the production of microgels in a large scale within a few minutes. The SRHMGs with an average size range of ∼ 1-4 μm contain O-acetyl-galactoglucomannan as a matrix and poly(acrylic acid), aniline pentamer (AP), and iron as functional additives, which are responsive to external changes in pH, electrochemical stimuli, magnetic field, or dual-stimuli. The surface morphologies, chemical compositions, charge, pH, and mechanical properties of these smart microgels were evaluated using scanning electron microscopy, IR, zeta potential measurements, pH evaluation, and quantitative nanomechanical mapping, respectively. Different oxidation states were observed when AP was introduced, as confirmed by UV spectroscopy and cyclic voltammetry. Systematic blood compatibility evaluations revealed that the SRHMGs have good blood compatibility. This bottom-up strategy to synthesize SRHMGs enables a new route to the production of smart microgels for biomedical applications.

Stimuli-responsive Smart Liposomes in Cancer Targeting.

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Jain, Ankit; Jain, Sanjay K

2018-02-08

Liposomes are vesicular carriers which possess aqueous core entrapped within the lipid bilayer. These are carriers of choice because of biocompatible and biodegradable features in addition to flexibility of surface modifications at surface and lipid compositions of lipid bilayers. Liposomes have been reported well for cancer treatment using both passive and active targeting approaches however tumor microenvironment is still the biggest hurdle for safe and effective delivery of anticancer agents. To overcome this problem, stimuli-responsive smart liposomes have emerged as promising cargoes pioneered to anomalous tumor milieu in response to pH, temperature, and enzymes etc. as internal triggers, and magnetic field, ultrasound, and redox potential as external guides for enhancement of drug delivery to tumors. This review focuses on all such stimuli-responsive approaches using fabrication potentiality of liposomes in combination to various ligands, linkers, and PEGylation etc. Scientists engaged in cancer targeting approaches can get benefited greatly with this knowledgeable assemblage of advances in liposomal nanovectors. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

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Mathieu B Brodeur

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

Premenstrual dysphoric disorder and prefrontal reactivity during anticipation of emotional stimuli.

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Gingnell, Malin; Bannbers, Elin; Wikström, Johan; Fredrikson, Mats; Sundström-Poromaa, Inger

2013-11-01

Premenstrual disorder (PMDD) affects around 5% of women in childbearing ages. An increased sensitivity in emotion processing areas of the brain to variations in ovarian steroid levels has been suggested as part of the pathophysiology in PMDD, but prior neuroimaging studies of emotion processing are yet inconclusive. Previous behavioral studies of women with PMDD have, however, reported enhanced luteal phase startle responsivity during emotional anticipation. Here we used functional magnetic resonance imaging (fMRI) to investigate central neural circuitry activity during anticipation of, and exposure to, emotional stimuli across the menstrual cycle in women with and without PMDD. As compared to healthy controls, women with PMDD displayed significantly enhanced reactivity in the prefrontal cortex during anticipation of, but not exposure to, negative emotional stimuli during the luteal phase. In PMDD patients, BOLD reactivity during anticipation or viewing of negative emotional stimuli was not dependent on absolute levels of estradiol or progesterone. However, progesterone levels were positively correlated with emotion-induced reactivity in the dorsolateral prefrontal cortex to positive emotional stimuli. These findings suggest that cortical emotional circuitry reactivity during anticipation is altered in PMDD during the luteal phase, which might be part of the pathophysiology behind the emotional symptoms or lack of emotional control reported by women with PMDD. © 2013 Elsevier B.V. and ECNP. All rights reserved.

Prevailing theories of consciousness are challenged by novel cross-modal associations acquired between subliminal stimuli.

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Scott, Ryan B; Samaha, Jason; Chrisley, Ron; Dienes, Zoltan

2018-06-01

While theories of consciousness differ substantially, the 'conscious access hypothesis', which aligns consciousness with the global accessibility of information across cortical regions, is present in many of the prevailing frameworks. This account holds that consciousness is necessary to integrate information arising from independent functions such as the specialist processing required by different senses. We directly tested this account by evaluating the potential for associative learning between novel pairs of subliminal stimuli presented in different sensory modalities. First, pairs of subliminal stimuli were presented and then their association assessed by examining the ability of the first stimulus to prime classification of the second. In Experiments 1-4 the stimuli were word-pairs consisting of a male name preceding either a creative or uncreative profession. Participants were subliminally exposed to two name-profession pairs where one name was paired with a creative profession and the other an uncreative profession. A supraliminal task followed requiring the timed classification of one of those two professions. The target profession was preceded by either the name with which it had been subliminally paired (concordant) or the alternate name (discordant). Experiment 1 presented stimuli auditorily, Experiment 2 visually, and Experiment 3 presented names auditorily and professions visually. All three experiments revealed the same inverse priming effect with concordant test pairs associated with significantly slower classification judgements. Experiment 4 sought to establish if learning would be more efficient with supraliminal stimuli and found evidence that a different strategy is adopted when stimuli are consciously perceived. Finally, Experiment 5 replicated the unconscious cross-modal association achieved in Experiment 3 utilising non-linguistic stimuli. The results demonstrate the acquisition of novel cross-modal associations between stimuli which are not

Depersonalization disorder: disconnection of cognitive evaluation from autonomic responses to emotional stimuli.

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Matthias Michal

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

Implicit and Explicit Associations with Erotic Stimuli in Women with and Without Sexual Problems.

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van Lankveld, Jacques J D M; Bandell, Myrthe; Bastin-Hurek, Eva; van Beurden, Myra; Araz, Suzan

2018-02-20

Conceptual models of sexual functioning have suggested a major role for implicit cognitive processing in sexual functioning. The present study aimed to investigate implicit and explicit cognition in sexual functioning in women. Gynecological patients with (N = 38) and without self-reported sexual problems (N = 41) were compared. Participants performed two Single-Target Implicit Association Tests (ST-IAT), measuring the implicit association of visual erotic stimuli with attributes representing, respectively, valence and motivation. Participants also rated the erotic pictures that were shown in the ST-IATs on the dimensions of valence, attractiveness, and sexual excitement, to assess their explicit associations with these erotic stimuli. Participants completed the Female Sexual Functioning Index and the Female Sexual Distress Scale for continuous measures of sexual functioning, and the Hospital Anxiety and Depression Scale to assess depressive symptoms. Compared to nonsymptomatic women, women with sexual problems were found to show more negative implicit associations of erotic stimuli with wanting (implicit sexual motivation). Across both groups, stronger implicit associations of erotic stimuli with wanting predicted higher level of sexual functioning. More positive explicit ratings of erotic stimuli predicted lower level of sexual distress across both groups.

Delivering high performance BWR fuel reliably

Energy Technology Data Exchange (ETDEWEB)

Schardt, J.F. [GE Nuclear Energy, Wilmington, NC (United States)

1998-07-01

Utilities are under intense pressure to reduce their production costs in order to compete in the increasingly deregulated marketplace. They need fuel, which can deliver high performance to meet demanding operating strategies. GE's latest BWR fuel design, GE14, provides that high performance capability. GE's product introduction process assures that this performance will be delivered reliably, with little risk to the utility. (author)

Effects of Temporal Congruity Between Auditory and Visual Stimuli Using Rapid Audio-Visual Serial Presentation.

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An, Xingwei; Tang, Jiabei; Liu, Shuang; He, Feng; Qi, Hongzhi; Wan, Baikun; Ming, Dong

2016-10-01

Combining visual and auditory stimuli in event-related potential (ERP)-based spellers gained more attention in recent years. Few of these studies notice the difference of ERP components and system efficiency caused by the shifting of visual and auditory onset. Here, we aim to study the effect of temporal congruity of auditory and visual stimuli onset on bimodal brain-computer interface (BCI) speller. We designed five visual and auditory combined paradigms with different visual-to-auditory delays (-33 to +100 ms). Eleven participants attended in this study. ERPs were acquired and aligned according to visual and auditory stimuli onset, respectively. ERPs of Fz, Cz, and PO7 channels were studied through the statistical analysis of different conditions both from visual-aligned ERPs and audio-aligned ERPs. Based on the visual-aligned ERPs, classification accuracy was also analyzed to seek the effects of visual-to-auditory delays. The latencies of ERP components depended mainly on the visual stimuli onset. Auditory stimuli onsets influenced mainly on early component accuracies, whereas visual stimuli onset determined later component accuracies. The latter, however, played a dominate role in overall classification. This study is important for further studies to achieve better explanations and ultimately determine the way to optimize the bimodal BCI application.

Gene expression analysis in response to osmotic stimuli in the intervertebral disc with DNA microarray.

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Zhang, Wenzhi; Li, Xu; Shang, Xifu; Zhao, Qichun; Hu, Yefeng; Xu, Xiang; He, Rui; Duan, Liqun; Zhang, Feng

2013-12-27

Intervertebral disc (IVD) cells experience a broad range of physicochemical stimuli under physiologic conditions, including alterations in their osmotic environment. At present, the molecular mechanisms underlying osmotic regulation in IVD cells are poorly understood. This study aims to screen genes affected by changes in osmotic pressure in cells of subjects aged 29 to 63 years old, with top-scoring pair (TSP) method. Gene expression data set GSE1648 was downloaded from Gene Expression Omnibus database, including four hyper-osmotic stimuli samples, four iso-osmotic stimuli samples, and three hypo-osmotic stimuli samples. A novel, simple method, referred to as the TSP, was used in this study. Through this method, there was no need to perform data normalization and transformation before data analysis. A total of five pairs of genes ((CYP2A6, FNTB), (PRPF8, TARDBP), (RPS5, OAZ1), (SLC25A3, NPM1) and (CBX3, SRSF9)) were selected based on the TSP method. We inferred that all these genes might play important roles in response to osmotic stimuli and age in IVD cells. Additionally, hyper-osmotic and iso-osmotic stimuli conditions were adverse factors for IVD cells. We anticipate that our results will provide new thoughts and methods for the study of IVD disease.

Adaptation to Variance of Stimuli in Drosophila Larva Navigation

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Wolk, Jason; Gepner, Ruben; Gershow, Marc

In order to respond to stimuli that vary over orders of magnitude while also being capable of sensing very small changes, neural systems must be capable of rapidly adapting to the variance of stimuli. We study this adaptation in Drosophila larvae responding to varying visual signals and optogenetically induced fictitious odors using an infrared illuminated arena and custom computer vision software. Larval navigational decisions (when to turn) are modeled as the output a linear-nonlinear Poisson process. The development of the nonlinear turn rate in response to changes in variance is tracked using an adaptive point process filter determining the rate of adaptation to different stimulus profiles. Supported by NIH Grant 1DP2EB022359 and NSF Grant PHY-1455015.

The subliminal mere exposure effect does not generalize to structurally related stimuli.

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Newell, Ben R; Bright, James E H

2003-03-01

R.F. Bornstein (1994) questioned whether subliminal mere exposure effects might generalize to structurally related stimuli, thereby providing evidence for the existence of implicit learning. Two experiments examined this claim using letter string stimuli constructed according to the rules of an artificial grammar. Experiment 1 demonstrated that brief, masked exposure to grammatical strings impaired recognition but failed to produce a mere exposure effect on novel structurally related strings seen at test. Experiment 2 replicated this result but also demonstrated that a reliable mere exposure effect could be obtained, provided the same grammatical strings were presented at test. The results suggest that the structural relationship between training and test items prevents the mere exposure effect when participants are unaware of the exposure status of stimuli, and therefore provide no evidence for the existence of implicit learning.

Amygdala reactivity to negative stimuli is influenced by oral contraceptive use.

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Petersen, Nicole; Cahill, Larry

2015-09-01

The amygdala is a highly interconnected region of the brain that is critically important to emotional processing and affective networks. Previous studies have shown that the response of the amygdala to emotionally arousing stimuli can be modulated by sex hormones. Because oral contraceptive pills dramatically lower circulating sex hormone levels with potent analogs of those hormones, we performed a functional magnetic resonance imaging experiment to measure amygdala reactivity in response to emotional stimuli in women using oral contraceptives, and compared their amygdala reactivity with that of naturally cycling women. Here, we show that women who use oral contraceptive pills have significantly decreased bilateral amygdala reactivity in response to negatively valenced, emotionally arousing stimuli compared with naturally cycling women. We suggest that by modulating amygdala reactivity, oral contraceptive pills may influence behaviors that have previously been shown to be amygdala dependent-in particular, emotional memory. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Gestalt perceptual organization of visual stimuli captures attention automatically: Electrophysiological evidence

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Francesco Marini

2016-08-01

Full Text Available The visual system leverages organizational regularities of perceptual elements to create meaningful representations of the world. One clear example of such function, which has been formalized in the Gestalt psychology principles, is the perceptual grouping of simple visual elements (e.g., lines and arcs into unitary objects (e.g., forms and shapes. The present study sought to characterize automatic attentional capture and related cognitive processing of Gestalt-like visual stimuli at the psychophysiological level by using event-related potentials (ERPs. We measured ERPs during a simple visual reaction time task with bilateral presentations of physically matched elements with or without a Gestalt organization. Results showed that Gestalt (vs. non-Gestalt stimuli are characterized by a larger N2pc together with enhanced ERP amplitudes of non-lateralized components (N1, N2, P3 starting around 150ms post-stimulus onset. Thus, we conclude that Gestalt stimuli capture attention automatically and entail characteristic psychophysiological signatures at both early and late processing stages.

Differential Memory of Picture and Word Stimuli in a Paired-Associate Learning Task.

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Bartels, Laura Grand; Feinbloom, Jessica

Ten concrete nouns represented in either a pictorial or a linguistic mode and accompanied by ten nonsense syllables were shown to 77 college students in a study of how pictorial stimuli varied in recall and recognition tasks. The group receiving pictorial stimuli recalled and recognized significantly more nonsense syllables than did the group…

FLIPPS for the Blind

DEFF Research Database (Denmark)

Bothe, Hans-Heinrich; Al-Hamdani, Sermed

2010-01-01

The idea of FLIPPS is to design, implement, and evaluate a vibro-tactile device that is composed of a photo diode, vibro-tactile stimulator, microcontroller and power supply. The stimulator is attached to the finger tip and activated when light illumination exceeds a defined threshold. The subject...

[WMN: a negative ERPs component related to working memory during non-target visual stimuli processing].

Science.gov (United States)

Zhao, Lun; Wei, Jin-he

2003-10-01

To study non-target stimuli processing in the brain. Features of the event-related potentials (ERPs) from non-target stimuli during selective response task (SR) was compared with that during visual selective discrimination (DR) task in 26 normal subjects. The stimuli consisted of two color LED flashes (red and green) appeared randomly in left (LVF) or right (RVF) visual field with same probability. ERPs were derived at 9 electrode sites on the scalp under 2 task conditions: a) SR, making switch response to the target (NT) stimuli from LVF or RVF in one direction and making no response to the non-target (NT) ones; b) DR, making switching response to T stimuli differentially, i.e., to the left for T from LVF and to the right for T from RVF. 1) the non-target stimuli in DR conditions, compared with that in SR condition, elicited smaller P2 and P3 components and larger N2 component at the frontal brain areas; 2) a significant negative component, named as WMN (working memory negativity), appeared in the non-target ERPs during DR in the period of 100 to 700 ms post stimulation which was predominant at the frontal brain areas. According to the major difference between brain activities for non-target stimuli during SR and DR, the predominant appearance of WMN at the frontal brain areas demonstrated that the non-target stimulus processing was an active process and was related to working memory, i.e., the temporary elimination and the retrieval of the response mode which was stored in working memory.

Materials Delivered by Member States

International Nuclear Information System (INIS)

1966-01-01

The information given in this document is divided into two parts. In part I the Director General is reporting to the Members of the Agency, under Article IX. G of the Statute, the quantities of materials delivered by Members up to 31 December 1965 in compliance with requests the Agency had made under Article IX. D. Part III contains information about materials which had not been delivered by 31 December but which had been allocated, in accordance with Article XI. F. 1 of the Statute, to approved Agency projects for which project arrangements were in force on that date

Materials Delivered by Member States

International Nuclear Information System (INIS)

1965-01-01

The information given in this document is divided into two parts. In part I the Director General is reporting to the Members of the Agency, under Article IX. G of the Statute, the quantities of materials delivered by Members up to 31 December 1964 in compliance with requests the Agency had made under Article IX. D. Part II contains information about materials which had not been delivered by 31 December but which had been allocated, in accordance with Article XI. F. 1 of the Statute, to approved Agency projects for which project arrangements were in force on that date

Materials Delivered by Member States

International Nuclear Information System (INIS)

1968-01-01

The information given in this document is divided into two parts. In part I the Director General is reporting to the Members of the Agency, under Article IX. G of the Statute, the quantities of materials delivered by Members up to 30 June 1968 in compliance with requests the Agency had made under Article IX,D. Part II contains information about materials which had not been delivered by 30 June 1968 but which had been allocated, in accordance with Article XI.F.I of the Statute, to approved Agency projects for which project arrangements were in force on that date

Reuse of ideas and concepts for creative stimuli in engineering design

DEFF Research Database (Denmark)

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

2011-01-01

Creative idea generation is essential to novel concept development and ultimately innovation. The following paper describes an extensive industry-based study investigating the use of creative stimuli during a brainstorming session at the conceptual stages of design.A new approach to retrieving...... real, industrially-based experiment regarding brainstorming. The results and observations suggest that having a guided approach to sourcing creative stimuli is very beneficial. The use of the TRIZ contradiction matrix and inventive principles is also shown to be a good example of a guided approach...

Afferent activity to necklace glomeruli is dependent on external stimuli

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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.

Automatic affective appraisal of sexual penetration stimuli in women with vaginismus or dyspareunia.

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Huijding, Jorg; Borg, Charmaine; Weijmar-Schultz, Willibrord; de Jong, Peter J

2011-03-01

Current psychological views are that negative appraisals of sexual stimuli lie at the core of sexual dysfunctions. It is important to differentiate between deliberate appraisals and more automatic appraisals, as research has shown that the former are most relevant to controllable behaviors, and the latter are most relevant to reflexive behaviors. Accordingly, it can be hypothesized that in women with vaginismus, the persistent difficulty to allow vaginal entry is due to global negative automatic affective appraisals that trigger reflexive pelvic floor muscle contraction at the prospect of penetration. To test whether sexual penetration pictures elicited global negative automatic affective appraisals in women with vaginismus or dyspareunia and to examine whether deliberate appraisals and automatic appraisals differed between the two patient groups. Women with persistent vaginismus (N = 24), dyspareunia (N = 23), or no sexual complaints (N = 30) completed a pictorial Extrinsic Affective Simon Task (EAST), and then made a global affective assessment of the EAST stimuli using visual analogue scales (VAS). The EAST assessed global automatic affective appraisals of sexual penetration stimuli, while the VAS assessed global deliberate affective appraisals of these stimuli. Automatic affective appraisals of sexual penetration stimuli tended to be positive, independent of the presence of sexual complaints. Deliberate appraisals of the same stimuli were significantly more negative in the women with vaginismus than in the dyspareunia group and control group, while the latter two groups did not differ in their appraisals. Unexpectedly, deliberate appraisals seemed to be most important in vaginismus, whereas dyspareunia did not seem to implicate negative deliberate or automatic affective appraisals. These findings dispute the view that global automatic affect lies at the core of vaginismus and indicate that a useful element in therapeutic interventions may be the modification of

Poly(ethyl glyoxylate)-Poly(ethylene oxide) Nanoparticles: Stimuli-Responsive Drug Release via End-to-End Polyglyoxylate Depolymerization.

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Fan, Bo; Gillies, Elizabeth R

2017-08-07

The ability to disrupt polymer assemblies in response to specific stimuli provides the potential to release drugs selectively at certain sites or conditions in vivo. However, most stimuli-responsive delivery systems require many stimuli-initiated events to release drugs. "Self-immolative polymers" offer the potential to provide amplified responses to stimuli as they undergo complete end-to-end depolymerization following the cleavage of a single end-cap. Herein, linker end-caps were developed to conjugate self-immolative poly(ethyl glyoxylate) (PEtG) with poly(ethylene oxide) (PEO) to form amphiphilic block copolymers. These copolymers were self-assembled to form nanoparticles in aqueous solution. Cleavage of the linker end-caps were triggered by a thiol reducing agent, UV light, H 2 O 2 , and combinations of these stimuli, resulting in nanoparticle disintegration. Low stimuli concentrations were effective in rapidly disrupting the nanoparticles. Nile red, doxorubin, and curcumin were encapsulated into the nanoparticles and were selectively released upon application of the appropriate stimulus. The ability to tune the stimuli-responsiveness simply by changing the linker end-cap makes this new platform highly attractive for applications in drug delivery.

A test of the symbol interdependency hypothesis with both concrete and abstract stimuli

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Buchanan, Lori

2018-01-01

In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks—one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli. PMID:29590121

A test of the symbol interdependency hypothesis with both concrete and abstract stimuli.

Science.gov (United States)

Malhi, Simritpal Kaur; Buchanan, Lori

2018-01-01

In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks-one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli.

Neural Conflict–Control Mechanisms Improve Memory for Target Stimuli

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

2015-01-01

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

Reversed stereo depth and motion direction with anti-correlated stimuli.

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Read, J C; Eagle, R A

2000-01-01

We used anti-correlated stimuli to compare the correspondence problem in stereo and motion. Subjects performed a two-interval forced-choice disparity/motion direction discrimination task for different displacements. For anti-correlated 1d band-pass noise, we found weak reversed depth and motion. With 2d anti-correlated stimuli, stereo performance was impaired, but the perception of reversed motion was enhanced. We can explain the main features of our data in terms of channels tuned to different spatial frequencies and orientation. We suggest that a key difference between the solution of the correspondence problem by the motion and stereo systems concerns the integration of information at different orientations.

4D bioprinting: the next-generation technology for biofabrication enabled by stimuli-responsive materials.

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Li, Yi-Chen; Zhang, Yu Shrike; Akpek, Ali; Shin, Su Ryon; Khademhosseini, Ali

2016-12-02

Four-dimensional (4D) bioprinting, encompassing a wide range of disciplines including bioengineering, materials science, chemistry, and computer sciences, is emerging as the next-generation biofabrication technology. By utilizing stimuli-responsive materials and advanced three-dimensional (3D) bioprinting strategies, 4D bioprinting aims to create dynamic 3D patterned biological structures that can transform their shapes or behavior under various stimuli. In this review, we highlight the potential use of various stimuli-responsive materials for 4D printing and their extension into biofabrication. We first discuss the state of the art and limitations associated with current 3D printing modalities and their transition into the inclusion of the additional time dimension. We then suggest the potential use of different stimuli-responsive biomaterials as the bioink that may achieve 4D bioprinting where transformation of fabricated biological constructs can be realized. We finally conclude with future perspectives.

Naltrexone alters the processing of social and emotional stimuli in healthy adults.

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Wardle, Margaret C; Bershad, Anya K; de Wit, Harriet

2016-12-01

Endogenous opioids have complex social effects that may depend on specific receptor actions and vary depending on the "stage" of social behavior (e.g., seeking vs. responding to social stimuli). We tested the effects of a nonspecific opioid antagonist, naltrexone (NTX), on social processing in humans. NTX is used to treat alcohol and opiate dependence, and may affect both mu and kappa-opioid systems. We assessed attention ("seeking"), and subjective and psychophysiological responses ("responding") to positive and negative social stimuli. Based on literature suggesting mu-opioid blockade impairs positive social responses, we hypothesized that NTX would decrease responses to positive social stimuli. We also tested responses to negative stimuli, which might be either increased by NTX's mu-opioid effects or decreased by its kappa-opioid effects. Thirty-four healthy volunteers received placebo, 25 mg, or 50 mg NTX across three sessions under double-blind conditions. At each session, participants completed measures of attention, identification, and emotional responses for emotional faces and scenes. NTX increased attention to emotional expressions, slowed identification of sadness and fear, and decreased ratings of arousal for social and nonsocial emotional scenes. These findings are more consistent with anxiolytic kappa-antagonist than mu-blocking effects, suggesting effects on kappa receptors may contribute to the clinical effects of NTX.

Fusion and rivalry are dependent on the perceptual meaning of visual stimuli.

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Andrews, Timothy J; Lotto, R Beau

2004-03-09

We view the world with two eyes and yet are typically only aware of a single, coherent image. Arguably the simplest explanation for this is that the visual system unites the two monocular stimuli into a common stream that eventually leads to a single coherent sensation. However, this notion is inconsistent with the well-known phenomenon of rivalry; when physically different stimuli project to the same retinal location, the ensuing perception alternates between the two monocular views in space and time. Although fundamental for understanding the principles of binocular vision and visual awareness, the mechanisms under-lying binocular rivalry remain controversial. Specifically, there is uncertainty about what determines whether monocular images undergo fusion or rivalry. By taking advantage of the perceptual phenomenon of color contrast, we show that physically identical monocular stimuli tend to rival-not fuse-when they signify different objects at the same location in visual space. Conversely, when physically different monocular stimuli are likely to represent the same object at the same location in space, fusion is more likely to result. The data suggest that what competes for visual awareness in the two eyes is not the physical similarity between images but the similarity in their perceptual/empirical meaning.

A SSVEP Stimuli Encoding Method Using Trinary Frequency-Shift Keying Encoded SSVEP (TFSK-SSVEP

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Xing Zhao

2017-06-01

Full Text Available SSVEP is a kind of BCI technology with advantage of high information transfer rate. However, due to its nature, frequencies could be used as stimuli are scarce. To solve such problem, a stimuli encoding method which encodes SSVEP signal using Frequency Shift–Keying (FSK method is developed. In this method, each stimulus is controlled by a FSK signal which contains three different frequencies that represent “Bit 0,” “Bit 1” and “Bit 2” respectively. Different to common BFSK in digital communication, “Bit 0” and “Bit 1” composited the unique identifier of stimuli in binary bit stream form, while “Bit 2” indicates the ending of a stimuli encoding. EEG signal is acquired on channel Oz, O1, O2, Pz, P3, and P4, using ADS1299 at the sample rate of 250 SPS. Before original EEG signal is quadrature demodulated, it is detrended and then band-pass filtered using FFT-based FIR filtering to remove interference. Valid peak of the processed signal is acquired by calculating its derivative and converted into bit stream using window method. Theoretically, this coding method could implement at least 2n−1 (n is the length of bit command stimulus while keeping the ITR the same. This method is suitable to implement stimuli on a monitor and where the frequency and phase could be used to code stimuli is limited as well as implementing portable BCI devices which is not capable of performing complex calculations.

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

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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.

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

Directory of Open Access Journals (Sweden)

Anne E. Ferrey

2012-12-01

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

Hot or Not: Response Inhibition Reduces the Hedonic Value and Motivational Incentive of Sexual Stimuli

Science.gov (United States)

Ferrey, Anne E.; Frischen, Alexandra; Fenske, Mark J.

2012-01-01

The motivational incentive of reward-related stimuli can become so salient that it drives behavior at the cost of other needs. Here we show that response inhibition applied during a Go/No-go task not only impacts hedonic evaluations but also reduces the behavioral incentive of motivationally relevant stimuli. We first examined the impact of response inhibition on the hedonic value of sex stimuli associated with strong behavioral-approach responses (Experiment 1). Sexually appealing and non-appealing images were both rated as less attractive when previously encountered as No-go (inhibited) than as Go (non-inhibited) items. We then discovered that inhibition reduces the motivational incentive of sexual appealing stimuli (Experiment 2). Prior Go/No-go status affected the number of key-presses by heterosexual males to view erotic-female (sexually appealing) but not erotic-male or scrambled-control (non-appealing) images. These findings may provide a foundation for developing inhibition-based interventions to reduce the hedonic value and motivational incentive of stimuli associated with disorders of self-control. PMID:23272002

Alternative Fuels Data Center: Seattle Bakery Delivers With Biodiesel

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Trucks Seattle Bakery Delivers With Biodiesel Trucks to someone by E-mail Share Alternative Fuels Data Center: Seattle Bakery Delivers With Biodiesel Trucks on Facebook Tweet about Alternative Fuels Data Center: Seattle Bakery Delivers With Biodiesel Trucks on Twitter Bookmark Alternative Fuels

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

Relating Attentional Biases for Stimuli Associated with Social Reward and Punishment to Autistic Traits

Directory of Open Access Journals (Sweden)

Brian A. Anderson

2018-04-01

Full Text Available Evidence for impaired attention to social stimuli in autism has been mixed. The role of social feedback in shaping attention to other, non-social stimuli that are predictive of such feedback has not been examined in the context of autism. In the present study, participants searched for a color-defined target during a training phase, with the color of the target predicting the emotional reaction of a face that appeared after each trial. Then, participants performed visual search for a shape-defined target while trying to ignore the color of stimuli. On a subset of trials, one of the non-targets was rendered in the color of a former target from training. Autistic traits were measured for each participant using the Autism Quotient (AQ. Our findings replicate robust attentional capture by stimuli learned to predict valenced social feedback. There was no evidence that autistic traits are associated with blunted attention to predictors of social outcomes. Consistent with an emerging body of literature, our findings cast doubt on strong versions of the claim that autistic traits can be explained by a blunted influence of social information on the attention system. We extend these findings to non-social stimuli that predict socially relevant information.

A novel method for delivering ramped cooling reveals rat behaviours at innocuous and noxious temperatures: A comparative study of human psychophysics and rat behaviour.

Science.gov (United States)

Dunham, James P; Hulse, Richard P; Donaldson, Lucy F

2015-07-15

Thermal sensory testing in rodents informs human pain research. There are important differences in the methodology for delivering thermal stimuli to humans and rodents. This is particularly true in cold pain research. These differences confound extrapolation and de-value nociceptive tests in rodents. We investigated cooling-induced behaviours in rats and psychophysical thresholds in humans using ramped cooling stimulation protocols. A Peltier device mounted upon force transducers simultaneously applied a ramped cooling stimulus whilst measuring contact with rat hind paw or human finger pad. Rat withdrawals and human detection, discomfort and pain thresholds were measured. Ramped cooling of a rat hind paw revealed two distinct responses: Brief paw removal followed by paw replacement, usually with more weight borne than prior to the removal (temperature inter-quartile range: 19.1 °C to 2.8 °C). Full withdrawal was evoked at colder temperatures (inter quartile range: -11.3 °C to -11.8 °C). The profile of human cool detection threshold and cold pain threshold were remarkably similar to that of the rat withdrawals behaviours. Previous rat cold evoked behaviours utilise static temperature stimuli. By utilising ramped cold stimuli this novel methodology better reflects thermal testing in patients. Brief paw removal in the rat is driven by non-nociceptive afferents, as is the perception of cooling in humans. This is in contrast to the nociceptor-driven withdrawal from colder temperatures. These findings have important implications for the interpretation of data generated in older cold pain models and consequently our understanding of cold perception and pain. Copyright © 2015. Published by Elsevier B.V.

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

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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…

Attentional and Affective Processing of Sexual Stimuli in Women with Hypoactive Sexual Desire Disorder

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Brauer, Marieke; van Leeuwen, Matthijs; Janssen, Erick; Newhouse, Sarah K.; Heiman, Julia R.; Laan, Ellen

2012-01-01

Hypoactive sexual desire disorder (HSDD) is the most common sexual problem in women. From an incentive motivation perspective, HSDD may be the result of a weak association between sexual stimuli and rewarding experiences. As a consequence, these stimuli may either lose or fail to acquire a positive

Effect of Waveform on Tactile Perception by Electrovibration Displayed on Touch Screens.

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Vardar, Yasemin; Guclu, Burak; Basdogan, Cagatay

2017-01-01

In this study, we investigated the effect of input voltage waveform on our haptic perception of electrovibration on touch screens. Through psychophysical experiments performed with eight subjects, we first measured the detection thresholds of electrovibration stimuli generated by sinusoidal and square voltages at various fundamental frequencies. We observed that the subjects were more sensitive to stimuli generated by square wave voltage than sinusoidal one for frequencies lower than 60 Hz. Using Matlab simulations, we showed that the sensation difference of waveforms in low fundamental frequencies occurred due to the frequency-dependent electrical properties of human skin and human tactile sensitivity. To validate our simulations, we conducted a second experiment with another group of eight subjects. We first actuated the touch screen at the threshold voltages estimated in the first experiment and then measured the contact force and acceleration acting on the index fingers of the subjects moving on the screen with a constant speed. We analyzed the collected data in the frequency domain using the human vibrotactile sensitivity curve. The results suggested that Pacinian channel was the primary psychophysical channel in the detection of the electrovibration stimuli caused by all the square-wave inputs tested in this study. We also observed that the measured force and acceleration data were affected by finger speed in a complex manner suggesting that it may also affect our haptic perception accordingly.

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

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

2016-12-01

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

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

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

2016-01-01

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

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

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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.

Do episodic migraineurs selectively attend to headache-related visual stimuli?

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McDermott, Michael J; Peck, Kelly R; Walters, A Brooke; Smitherman, Todd A

2013-02-01

To assess pain-related attentional biases among individuals with episodic migraine. Prior studies have examined whether chronic pain patients selectively attend to pain-related stimuli in the environment, but these studies have produced largely mixed findings and focused primarily on patients with chronic musculoskeletal pain. Limited research has implicated attentional biases among chronic headache patients, but no studies have been conducted among episodic migraineurs, who comprise the overwhelming majority of the migraine population. This was a case-control, experimental study. Three hundred and eight participants (mean age = 19.2 years [standard deviation = 3.3]; 69.5% female; 36.4% minority), consisting of 84 episodic migraineurs, diagnosed in accordance with International Classification of Headache Disorders (2(nd) edition) criteria using a structured diagnostic interview, and 224 non-migraine controls completed a computerized dot probe task to assess attentional bias toward headache-related pictorial stimuli. The task consisted of 192 trials and utilized 2 emotional-neutral stimulus pairing conditions (headache-neutral and happy-neutral). No within-group differences for reaction time latencies to headache vs happy conditions were found among those with episodic migraine or among the non-migraine controls. Migraine status was unrelated to attentional bias indices for both headache (F [1,306] = 0.56, P = .45) and happy facial stimuli (F [1,306] = 0.37, P = .54), indicating a lack of between-group differences. Lack of within- and between-group differences was confirmed with repeated measures analysis of variance. In light of the large sample size and prior pilot testing of presented images, results suggest that episodic migraineurs do not differentially attend to headache-related facial stimuli. Given modest evidence of attentional biases among chronic headache samples, these findings suggest potential differences in attentional

The effects of dissociation on information processing for analogue trauma and neutral stimuli: a laboratory study.

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Olsen, Shira A; Beck, J Gayle

2012-01-01

This study investigated the effects of high and low levels of dissociation on information processing for analogue trauma and neutral stimuli. Fifty-four undergraduate females who reported high and low levels of trait dissociation were presented with two films, one depicting traumatic events, the other containing neutral material. Participants completed a divided attention task (yielding a proxy measure of attention), as well as explicit memory (free-recall) and implicit memory (word-stem completion) tasks for both films. Results indicated that the high DES group showed less attention and had poorer recall for the analogue trauma stimuli, relative to the neutral stimuli and the low DES group. These findings suggest that high levels of trait dissociation are associated with reductions in attention and memory for analogue trauma stimuli, relative to neutral stimuli and relative to low trait dissociation. Implications for the role of cognitive factors in the etiology of negative post-trauma responses are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sex Attracts: Investigating Individual Differences in Attentional Bias to Sexual Stimuli

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Kagerer, Sabine; Wehrum, Sina; Klucken, Tim; Walter, Bertram; Vaitl, Dieter; Stark, Rudolf

2014-01-01

We investigated the impact of sexual stimuli and the influence of sexual motivation on the performance in a dot-probe task and a line-orientation task in a large sample of males and females. All pictures (neutral, erotic) were rated on the dimensions of valence, arousal, disgust, and sexual arousal. Additionally, questionnaires measuring sexual interest/desire/motivation were employed. The ratings of the sexual stimuli point to a successful picture selection because sexual arousal did not differ between the sexes. The stimuli were equally arousing for men and women. Higher scores in the employed questionnaires measuring sexual interest/desire/motivation led to higher sexual arousal ratings of the sex pictures. Attentional bias towards sex pictures was observed in both experimental tasks. The attentional biases measured by the dot-probe and the line-orientation task were moderately intercorrelated suggesting attentional bias as a possible marker for a sex-attention trait. Finally, only the sexual sensation seeking score correlated with the attentional biases of the two tasks. Future research is needed to increase the predictive power of these indirect measures of sexual interest. PMID:25238545

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

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

2006-01-01

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

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

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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

Gender differences in pre-attentive change detection for visual but not auditory stimuli.

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Yang, Xiuxian; Yu, Yunmiao; Chen, Lu; Sun, Hailian; Qiao, Zhengxue; Qiu, Xiaohui; Zhang, Congpei; Wang, Lin; Zhu, Xiongzhao; He, Jincai; Zhao, Lun; Yang, Yanjie

2016-01-01

Despite ongoing debate about gender differences in pre-attention processes, little is known about gender effects on change detection for auditory and visual stimuli. We explored gender differences in change detection while processing duration information in auditory and visual modalities. We investigated pre-attentive processing of duration information using a deviant-standard reverse oddball paradigm (50 ms/150 ms) for auditory and visual mismatch negativity (aMMN and vMMN) in males and females (n=21/group). In the auditory modality, decrement and increment aMMN were observed at 150-250 ms after the stimulus onset, and there was no significant gender effect on MMN amplitudes in temporal or fronto-central areas. In contrast, in the visual modality, only increment vMMN was observed at 180-260 ms after the onset of stimulus, and it was higher in males than in females. No gender effect was found in change detection for auditory stimuli, but change detection was facilitated for visual stimuli in males. Gender effects should be considered in clinical studies of pre-attention for visual stimuli. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Neural conflict-control mechanisms improve memory for target stimuli.

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

2015-03-01

According to conflict-monitoring models, conflict serves as an internal signal for reinforcing top-down attention to task-relevant information. While evidence based on measures of ongoing task performance supports this idea, implications for long-term consequences, that is, memory, have not been tested yet. Here, we evaluated the prediction that conflict-triggered attentional enhancement of target-stimulus processing should be associated with superior subsequent memory for those stimuli. By combining functional magnetic resonance imaging (fMRI) with a novel variant of a face-word Stroop task that employed trial-unique face stimuli as targets, we were able to assess subsequent (incidental) memory for target faces as a function of whether a given face had previously been accompanied by congruent, neutral, or incongruent (conflicting) distracters. In line with our predictions, incongruent distracters not only induced behavioral conflict, but also gave rise to enhanced memory for target faces. Moreover, conflict-triggered neural activity in prefrontal and parietal regions was predictive of subsequent retrieval success, and displayed conflict-enhanced functional coupling with medial-temporal lobe regions. These data provide support for the proposal that conflict evokes enhanced top-down attention to task-relevant stimuli, thereby promoting their encoding into long-term memory. Our findings thus delineate the neural mechanisms of a novel link between cognitive control and memory. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Effects of chemesthetic stimuli mixtures with barium on swallowing apnea duration.

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Todd, J Tee; Butler, Susan G; Plonk, Drew P; Grace-Martin, Karen; Pelletier, Cathy A

2012-10-01

This study tested the hypotheses that swallowing apnea duration (SAD) will increase given barium versus water, chemesthetic stimuli (i.e., water barium, age (older > younger), and genetic taste differences (supertasters > nontasters). Prospective group design. University Medical Center. Eighty healthy women were identified as nontasters and supertasters, equally comprising two age groups: 18 to 35 years and 60+ years. The KayPentax Swallowing Signals Lab was used to acquire SAD via nasal cannula during individually randomized swallows of 5 mL barium, 2.7% w/v citric acid with barium, carbonation with barium, and 50:50 diluted ethanol with barium. Data were analyzed using path analysis, with the mediator of chemesthetic perception, adjusted for repeated measures. Significant main effects of age (P = .012) and chemesthetic stimuli (P = .014) were found, as well as a significant interaction between chemesthetic stimuli and age (P = .028). Older women had a significantly longer SAD than younger women. Post hoc analyses revealed that barium mixed with ethanol elicited a significantly longer SAD than other bolus conditions, regardless of age group. There were no significant differences in SAD between barium and water conditions, and no significant effect of chemesthetic perception (P > .05). Ethanol added to barium elicited longer SAD compared to plain barium, but not the other chemesthetic conditions. Older women had a longer SAD than younger women in all conditions. These findings may influence design of future studies examining effects of various stimuli on SAD. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Mid-adolescent neurocognitive development of ignoring and attending emotional stimuli

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Nora C. Vetter

2015-08-01

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

Differences in Swallowing between High and Low Concentration Taste Stimuli

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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.

Artificial Cochlear Sensory Epithelium with Functions of Outer Hair Cells Mimicked Using Feedback Electrical Stimuli

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Tetsuro Tsuji

2018-05-01

Full Text Available We report a novel vibration control technique of an artificial auditory cochlear epithelium that mimics the function of outer hair cells in the organ of Corti. The proposed piezoelectric and trapezoidal membrane not only has the acoustic/electric conversion and frequency selectivity of the previous device developed mainly by one of the authors and colleagues, but also has a function to control local vibration according to sound stimuli. Vibration control is achieved by applying local electrical stimuli to patterned electrodes on an epithelium made using micro-electro-mechanical system technology. By choosing appropriate phase differences between sound and electrical stimuli, it is shown that it is possible to both amplify and dampen membrane vibration, realizing better control of the response of the artificial cochlea. To be more specific, amplification and damping are achieved when the phase difference between the membrane vibration by sound stimuli and electrical stimuli is zero and π , respectively. We also demonstrate that the developed control system responds automatically to a change in sound frequency. The proposed technique can be applied to mimic the nonlinear response of the outer hair cells in a cochlea, and to realize a high-quality human auditory system.

Predatory behavior inTupinambis teguixin (Sauria: Teiidae). I. Tongue-flicking responses to chemical food stimuli.

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Yanosky, A A; Iriart, D E; Mercolli, C

1993-02-01

Black tegu lizards (Tupinambis teguixin) have the ability to detect food odors and discriminate between them and nonfood odors. This was tested by offering chemical stimuli on cotton-tipped applicators to the animals. Stimuli were from two plant and two animal species known to be principal items in these lizards' diets, demineralized water as an odorless control, and eaude-cologne as an odorous control lacking feeding or social importance. Tongueflick attack score, latency to attack, preattack tongue-flicks, and number of attacks were analyzed. The results clearly demonstrated that this species responds to chemical food stimuli, but does not respond to odorless nonfood stimuli. Responses differed among food types. There were no sex differences. These results are in agreement with the prediction that lizards having forked tongues and an active foraging mode rely on chemical cues for feeding.

Stimuli-responsive hydrogels in drug delivery and tissue engineering.

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

2016-01-01

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

Learning of arbitrary association between visual and auditory novel stimuli in adults: the "bond effect" of haptic exploration.

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Benjamin Fredembach

Full Text Available BACKGROUND: It is well-known that human beings are able to associate stimuli (novel or not perceived in their environment. For example, this ability is used by children in reading acquisition when arbitrary associations between visual and auditory stimuli must be learned. The studies tend to consider it as an "implicit" process triggered by the learning of letter/sound correspondences. The study described in this paper examined whether the addition of the visuo-haptic exploration would help adults to learn more effectively the arbitrary association between visual and auditory novel stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Adults were asked to learn 15 new arbitrary associations between visual stimuli and their corresponding sounds using two learning methods which differed according to the perceptual modalities involved in the exploration of the visual stimuli. Adults used their visual modality in the "classic" learning method and both their visual and haptic modalities in the "multisensory" learning one. After both learning methods, participants showed a similar above-chance ability to recognize the visual and auditory stimuli and the audio-visual associations. However, the ability to recognize the visual-auditory associations was better after the multisensory method than after the classic one. CONCLUSION/SIGNIFICANCE: This study revealed that adults learned more efficiently the arbitrary association between visual and auditory novel stimuli when the visual stimuli were explored with both vision and touch. The results are discussed from the perspective of how they relate to the functional differences of the manual haptic modality and the hypothesis of a "haptic bond" between visual and auditory stimuli.

Differential coactivation in a redundant signals task with weak and strong go/no-go stimuli

DEFF Research Database (Denmark)

Minakata, Katsumi; Gondan, Matthias

2018-01-01

When participants respond to stimuli of two sources, response times (RT) are often faster when both stimuli are presented together relative to the RTs obtained when presented separately (redundant signals effect, RSE). Race models and coactivation models can explain the RSE. In race models......, separate channels process the two stimulus components, and the faster processing time determines the overall RT. In audiovisual experiments, the RSE is often higher than predicted by race models, and coactivation models have been proposed that assume integrated processing of the two stimuli. Where does...

An fMRI investigation into the effect of preceding stimuli during visual oddball tasks.

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Fajkus, Jiří; Mikl, Michal; Shaw, Daniel Joel; Brázdil, Milan

2015-08-15

This study investigates the modulatory effect of stimulus sequence on neural responses to novel stimuli. A group of 34 healthy volunteers underwent event-related functional magnetic resonance imaging while performing a three-stimulus visual oddball task, involving randomly presented frequent stimuli and two types of infrequent stimuli - targets and distractors. We developed a modified categorization of rare stimuli that incorporated the type of preceding rare stimulus, and analyzed the event-related functional data according to this sequence categorization; specifically, we explored hemodynamic response modulation associated with increasing rare-to-rare stimulus interval. For two consecutive targets, a modulation of brain function was evident throughout posterior midline and lateral temporal cortex, while responses to targets preceded by distractors were modulated in a widely distributed fronto-parietal system. As for distractors that follow targets, brain function was modulated throughout a set of posterior brain structures. For two successive distractors, however, no significant modulation was observed, which is consistent with previous studies and our primary hypothesis. The addition of the aforementioned technique extends the possibilities of conventional oddball task analysis, enabling researchers to explore the effects of the whole range of rare stimuli intervals. This methodology can be applied to study a wide range of associated cognitive mechanisms, such as decision making, expectancy and attention. Copyright © 2015 Elsevier B.V. All rights reserved.

Bio-inspired fabrication of stimuli-responsive photonic crystals with hierarchical structures and their applications

International Nuclear Information System (INIS)

Lu, Tao; Peng, Wenhong; Zhu, Shenmin; Zhang, Di

2016-01-01

When the constitutive materials of photonic crystals (PCs) are stimuli-responsive, the resultant PCs exhibit optical properties that can be tuned by the stimuli. This can be exploited for promising applications in colour displays, biological and chemical sensors, inks and paints, and many optically active components. However, the preparation of the required photonic structures is the first issue to be solved. In the past two decades, approaches such as microfabrication and self-assembly have been developed to incorporate stimuli-responsive materials into existing periodic structures for the fabrication of PCs, either as the initial building blocks or as the surrounding matrix. Generally, the materials that respond to thermal, pH, chemical, optical, electrical, or magnetic stimuli are either soft or aggregate, which is why the manufacture of three-dimensional hierarchical photonic structures with responsive properties is a great challenge. Recently, inspired by biological PCs in nature which exhibit both flexible and responsive properties, researchers have developed various methods to synthesize metals and metal oxides with hierarchical structures by using a biological PC as the template. This review will focus on the recent developments in this field. In particular, PCs with biological hierarchical structures that can be tuned by external stimuli have recently been successfully fabricated. These findings offer innovative insights into the design of responsive PCs and should be of great importance for future applications of these materials. (topical review)

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

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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…

A Stimuli-Responsive Biosensor of Glucose on Layer-by-Layer Films Assembled through Specific Lectin-Glycoenzyme Recognition

Directory of Open Access Journals (Sweden)

Huiqin Yao

2016-04-01

Full Text Available The research on intelligent bioelectrocatalysis based on stimuli-responsive materials or interfaces is of great significance for biosensors and other bioelectronic devices. In the present work, lectin protein concanavalin A (Con A and glycoenzyme glucose oxidase (GOD were assembled into {Con A/GOD}n layer-by-layer (LbL films by taking advantage of the biospecific lectin-glycoenzyme affinity between them. These film electrodes possess stimuli-responsive properties toward electroactive probes such as ferrocenedicarboxylic acid (Fc(COOH2 by modulating the surrounding pH. The CV peak currents of Fc(COOH2 were quite large at pH 4.0 but significantly suppressed at pH 8.0, demonstrating reversible stimuli-responsive on-off behavior. The mechanism of stimuli-responsive property of the films was explored by comparative experiments and attributed to the different electrostatic interaction between the films and the probes at different pH. This stimuli-responsive films could be used to realize active/inactive electrocatalytic oxidation of glucose by GOD in the films and mediated by Fc(COOH2 in solution, which may establish a foundation for fabricating novel stimuli-responsive electrochemical biosensors based on bioelectrocatalysis with immobilized enzymes.

Crosslinked ionic polysaccharides for stimuli-sensitive drug delivery.

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

2013-08-01

Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems, particularly since they can be obtained in a well characterized and reproducible way from the natural sources. Ionic polysaccharides can be readily crosslinked to render hydrogel networks sensitive to a variety of internal and external variables, and thus suitable for switching drug release on-off through diverse mechanisms. Hybrids, composites and grafted polymers can reinforce the responsiveness and widen the range of stimuli to which polysaccharide-based systems can respond. This review analyzes the state of the art of crosslinked ionic polysaccharides as components of delivery systems that can regulate drug release as a function of changes in pH, ion nature and concentration, electric and magnetic field intensity, light wavelength, temperature, redox potential, and certain molecules (enzymes, illness markers, and so on). Examples of specific applications are provided. The information compiled demonstrates that crosslinked networks of ionic polysaccharides are suitable building blocks for developing advanced externally activated and feed-back modulated drug delivery systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Swimming micro-robot powered by stimuli-sensitive gel

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Masoud, Hassan; Alexeev, Alexander

2012-11-01

Using three-dimensional computer simulations, we design a simple maneuverable micro-swimmer that can self-propel and navigate in highly viscous (low Reynolds-number) environments. Our simple swimmer consists of a cubic gel body which periodically changes volume in response to external stimuli, two rigid rectangular flaps attached to the opposite sides of the gel body, and a flexible steering flap at the front end of the swimmer. The stimuli-sensitive body undergoes periodic expansions (swelling) and contractions (deswelling) leading to a time-irreversible beating motion of the propulsive flaps that propel the micro-swimmer. Thus, the responsive gel body acts as an ``engine'' actuating the motion of the swimmer. We examine how the swimming speed depends on the gel and flap properties. We also probe how the swimmer trajectory can be changed using a responsive steering flap whose curvature is controlled by an external stimulus. We show that the turning occurs due to steering flap bending and periodic beating. Furthermore, our simulations reveal that the turning direction can be regulated by changing the intensity of external stimulus.

The effects of using stimuli from three different dimensions on autoshaping with a complex negative patterning discrimination.

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Pearce, John M; George, David N

2002-10-01

In two experiments pigeons received a complex negative patterning discrimination, using autoshaping, in which food was made available after three stimuli if they were presented alone (A, B, C), or in pairs (AB, AC, BC), but not when they were all presented together (ABC). Subjects also received a positive patterning discrimination in which three additional stimuli were not followed by food when presented alone (D, E, F), or in pairs (DE, DF, EF), but they were followed by food when presented together (DEF). Stimuli A and D belonged to one dimension, B and E to a second dimension, and D and F to a third dimension. For both problems, the discrimination between the individual stimuli and the triple-element compounds developed more readily than that between the pairs of stimuli and the triple-element compound. The results are consistent with predictions that can be derived from a configural theory of conditioning.

Pupil responses and pain ratings to heat stimuli: Reliability and effects of expectations and a conditioning pain stimulus.

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Eisenach, James C; Curry, Regina; Aschenbrenner, Carol A; Coghill, Robert C; Houle, Timothy T

2017-03-01

The locus coeruleus (LC) signals salience to sensory stimuli and these responses can modulate the experience of pain stimuli. The pupil dilation response (PDR) to noxious stimuli is thought to be a surrogate for LC responses, but PDR response to Peltier-controlled noxious heat stimuli, the most commonly used method in experimental pain research, has not been described. Healthy volunteers were presented with randomly presented heat stimuli of 5 sec duration and provided pain intensity ratings to each stimulus. Pupillometry was performed and a method developed to quantify the PDR relevant to these stimuli. The stimulus response, reliability, and effect of commonly used manipulations on pain experience were explored. A method of artifact removal and adjusting for lag from stimulus initiation to PDR response was developed, resulting in a close correlation between pain intensity rating and PDR across a large range of heat stimuli. A reliable assessment of PDR within an individual was achieved with fewer presentations as heat stimulus intensity increased. The correlation between pain rating and PDR was disrupted when cognitive load is increased by manipulating expectations or presenting a second pain stimulus. The PDR began later after skin heating than electrical stimuli and this is the first examination of the PDR using standard nociceptive testing and manipulations of expectations and competing noxious stimulation. A method is described applying PDR to standard heat nociceptive testing, demonstrating stimulus response, reliability, and disruption by cognitive manipulation. Copyright © 2017 Elsevier B.V. All rights reserved.

The presence of a culturally similar or dissimilar social partner affects neural responses to emotional stimuli

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Kate A. Woodcock

2013-06-01

Full Text Available Background: Emotional responding is sensitive to social context; however, little emphasis has been placed on the mechanisms by which social context effects changes in emotional responding. Objective: We aimed to investigate the effects of social context on neural responses to emotional stimuli to inform on the mechanisms underpinning context-linked changes in emotional responding. Design: We measured event-related potential (ERP components known to index specific emotion processes and self-reports of explicit emotion regulation strategies and emotional arousal. Female Chinese university students observed positive, negative, and neutral photographs, whilst alone or accompanied by a culturally similar (Chinese or dissimilar researcher (British. Results: There was a reduction in the positive versus neutral differential N1 amplitude (indexing attentional capture by positive stimuli in the dissimilar relative to alone context. In this context, there was also a corresponding increase in amplitude of a frontal late positive potential (LPP component (indexing engagement of cognitive control resources. In the similar relative to alone context, these effects on differential N1 and frontal LPP amplitudes were less pronounced, but there was an additional decrease in the amplitude of a parietal LPP component (indexing motivational relevance in response to positive stimuli. In response to negative stimuli, the differential N1 component was increased in the similar relative to dissimilar and alone (trend context. Conclusion: These data suggest that neural processes engaged in response to emotional stimuli are modulated by social context. Possible mechanisms for the social-context-linked changes in attentional capture by emotional stimuli include a context-directed modulation of the focus of attention, or an altered interpretation of the emotional stimuli based on additional information proportioned by the context.

Sex differences in event-related potentials and attentional biases to emotional facial stimuli.

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Pfabigan, Daniela M; Lamplmayr-Kragl, Elisabeth; Pintzinger, Nina M; Sailer, Uta; Tran, Ulrich S

2014-01-01

Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women) performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Using the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies.

Comparative assessment of intrinsic mechanical stimuli on knee cartilage and compressed agarose constructs.

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Completo, A; Bandeiras, C; Fonseca, F

2017-06-01

A well-established cue for improving the properties of tissue-engineered cartilage is mechanical stimulation. However, the explicit ranges of mechanical stimuli that correspond to favorable metabolic outcomes are elusive. Usually, these outcomes have only been associated with the applied strain and frequency, an oversimplification that can hide the fundamental relationship between the intrinsic mechanical stimuli and the metabolic outcomes. This highlights two important key issues: the firstly is related to the evaluation of the intrinsic mechanical stimuli of native cartilage; the second, assuming that the intrinsic mechanical stimuli will be important, deals with the ability to replicate them on the tissue-engineered constructs. This study quantifies and compares the volume of cartilage and agarose subjected to a given magnitude range of each intrinsic mechanical stimulus, through a numerical simulation of a patient-specific knee model coupled with experimental data of contact during the stance phase of gait, and agarose constructs under direct-dynamic compression. The results suggest that direct compression loading needs to be parameterized with time-dependence during the initial culture period in order to better reproduce each one of the intrinsic mechanical stimuli developed in the patient-specific cartilage. A loading regime which combines time periods of low compressive strain (5%) and frequency (0.5Hz), in order to approach the maximal principal strain and fluid velocity stimulus of the patient-specific cartilage, with time periods of high compressive strain (20%) and frequency (3Hz), in order to approach the pore pressure values, may be advantageous relatively to a single loading regime throughout the full culture period. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Sex differences in event-related potentials and attentional biases to emotional facial stimuli

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Daniela M. Pfabigan

2014-12-01

Full Text Available Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Under the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies.

Beyond arousal and valence: the importance of the biological versus social relevance of emotional stimuli.

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Sakaki, Michiko; Niki, Kazuhisa; Mather, Mara

2012-03-01

The present study addressed the hypothesis that emotional stimuli relevant to survival or reproduction (biologically emotional stimuli) automatically affect cognitive processing (e.g., attention, memory), while those relevant to social life (socially emotional stimuli) require elaborative processing to modulate attention and memory. Results of our behavioral studies showed that (1) biologically emotional images hold attention more strongly than do socially emotional images, (2) memory for biologically emotional images was enhanced even with limited cognitive resources, but (3) memory for socially emotional images was enhanced only when people had sufficient cognitive resources at encoding. Neither images' subjective arousal nor their valence modulated these patterns. A subsequent functional magnetic resonance imaging study revealed that biologically emotional images induced stronger activity in the visual cortex and greater functional connectivity between the amygdala and visual cortex than did socially emotional images. These results suggest that the interconnection between the amygdala and visual cortex supports enhanced attention allocation to biological stimuli. In contrast, socially emotional images evoked greater activity in the medial prefrontal cortex (MPFC) and yielded stronger functional connectivity between the amygdala and MPFC than did biological images. Thus, it appears that emotional processing of social stimuli involves elaborative processing requiring frontal lobe activity.

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

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

2013-01-01

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

Materials Delivered by Member States

International Nuclear Information System (INIS)

1962-01-01

The information given in this document is divided into two parts. In part I the Director General is reporting to the Members of the Agency, under Article IX. G of the Statute, the quantities of materials delivered up to 30 September 1962 by Member States in compliance with requests the Agency has made under Article IX. D. Part II contains information about materials which have not yet been delivered but which have been allocated, in accordance with Article XI. F. 1 of the Statute, to approved Agency projects for which project agreements were in force on 30 September 1962. Reports on subsequent deliveries of materials and revised information about allocated but undelivered materials will be issued from time to time

Sex attracts: investigating individual differences in attentional bias to sexual stimuli.

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Sabine Kagerer

Full Text Available We investigated the impact of sexual stimuli and the influence of sexual motivation on the performance in a dot-probe task and a line-orientation task in a large sample of males and females. All pictures (neutral, erotic were rated on the dimensions of valence, arousal, disgust, and sexual arousal. Additionally, questionnaires measuring sexual interest/desire/motivation were employed. The ratings of the sexual stimuli point to a successful picture selection because sexual arousal did not differ between the sexes. The stimuli were equally arousing for men and women. Higher scores in the employed questionnaires measuring sexual interest/desire/motivation led to higher sexual arousal ratings of the sex pictures. Attentional bias towards sex pictures was observed in both experimental tasks. The attentional biases measured by the dot-probe and the line-orientation task were moderately intercorrelated suggesting attentional bias as a possible marker for a sex-attention trait. Finally, only the sexual sensation seeking score correlated with the attentional biases of the two tasks. Future research is needed to increase the predictive power of these indirect measures of sexual interest.

Thoughts of death modulate psychophysical and cortical responses to threatening stimuli.

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Elia Valentini

Full Text Available Existential social psychology studies show that awareness of one's eventual death profoundly influences human cognition and behaviour by inducing defensive reactions against end-of-life related anxiety. Much less is known about the impact of reminders of mortality on brain activity. Therefore we explored whether reminders of mortality influence subjective ratings of intensity and threat of auditory and painful thermal stimuli and the associated electroencephalographic activity. Moreover, we explored whether personality and demographics modulate psychophysical and neural changes related to mortality salience (MS. Following MS induction, a specific increase in ratings of intensity and threat was found for both nociceptive and auditory stimuli. While MS did not have any specific effect on nociceptive and auditory evoked potentials, larger amplitude of theta oscillatory activity related to thermal nociceptive activity was found after thoughts of death were induced. MS thus exerted a top-down modulation on theta electroencephalographic oscillatory amplitude, specifically for brain activity triggered by painful thermal stimuli. This effect was higher in participants reporting higher threat perception, suggesting that inducing a death-related mind-set may have an influence on body-defence related somatosensory representations.

Appetitive Pavlovian conditioned stimuli increase CREB phosphorylation in the nucleus accumbens.

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Shiflett, Michael W; Mauna, Jocelyn C; Chipman, Amanda M; Peet, Eloise; Thiels, Edda

2009-10-01

The transcription factor cAMP response element-binding protein (CREB) in the nucleus accumbens (NAc) has been shown to regulate an animal's behavioral responsiveness to emotionally salient stimuli, and an increase in CREB phosphorylation in the NAc has been observed during exposure to rewarding stimuli, such as drugs of abuse. Here we show that CREB phosphorylation increases in the NAc also during exposure to cues that an animal has associated with delivery of natural rewards. Adult male Sprague-Dawley rats (rattus norvegicus) were trained to associate an auditory stimulus with delivery of food pellets, and CREB phosphorylation was examined in the striatum following training. We found that repeated tone-food pairings resulted in an increase in CREB phosphorylation in the NAc but not in the adjacent dorsal striatum or in the NAc 3h after the final training session. We further found that the cue itself, as opposed to the food pellets, the training context, or tone-food pairings, was sufficient to increase CREB phosphorylation in the NAc. These results suggest that the processing of primary rewarding stimuli and of environmental cues that predict them triggers similar accumbal signaling mechanisms.

Design, synthesis, and film formation of stimuli-responsive colloidal dispersions containing phospholipids

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Lestage, David Jackson

These studies were undertaken to further understand the design of colloidal dispersions containing bio-active phospholipids (PL) as stabilizing agents and their stimuli-responsive behaviors during film formation. Methyl methacrylate (MMA) and n-butyl acrylate (nBA) dispersions were synthesized using anionic surfactants and PL, and the surface-responsiveness of coalesced films was monitored at the film-air (F-A) and film-substrate (F-S) interfaces after exposure to temperature, UV, pH, ionic strength, and enzymatic stimuli. Using spectroscopic molecular-level probes such as attenuated total reflectance (ATR) and internal reflection IR imaging (IRIRI), these studies show that structural features of PL and surfactants significantly affect stimuli-responsiveness of polymeric films. MMA/nBA homopolymer, blend, copolymer, and core-shell particle coalescence studies indicated that controlled permeability is influenced by particle composition and sodium dioctyl sulfosuccinate (SDOSS) mobility to the F-A interface is enhanced in response to temperature. Utilization of hydrogenated soybean phosphocholine (HSPC) as a co-surfactant with SDOSS resulted in bimodal p-MMA/nBA colloidal particles, and experiments showed that ionic interactions with HSPC inhibit SDOSS mobility. However, the controlled release of individual species is detected in the presence of Ca2+ ionic strength stimuli. Utilizing 1,2-bis(10,12-tricosadiynoyl)- sn-glycero-3-phosphocholine (DCPC), cocklebur-shape particle morphologies were obtained and using transmission electron microscopy (TEM), self-assembled tubules were detected at particle interfaces, but not in the presence of Ca 2+. At altered concentration levels of DCPC, surface localized ionic clusters (SLICs) composed of SDOSS and DCPC form at the F-A and F-S interfaces in response to temperature and ionic strength stimuli. Micelle formation of 1-myristoyl-2-hydroxy-sn-glycero-phosphocholine (MHPC) stabilizes unimodal p-MMA/nBA colloidal particles

Visual sensitivity for luminance and chromatic stimuli during the execution of smooth pursuit and saccadic eye movements.

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Braun, Doris I; Schütz, Alexander C; Gegenfurtner, Karl R

2017-07-01

Visual sensitivity is dynamically modulated by eye movements. During saccadic eye movements, sensitivity is reduced selectively for low-spatial frequency luminance stimuli and largely unaffected for high-spatial frequency luminance and chromatic stimuli (Nature 371 (1994), 511-513). During smooth pursuit eye movements, sensitivity for low-spatial frequency luminance stimuli is moderately reduced while sensitivity for chromatic and high-spatial frequency luminance stimuli is even increased (Nature Neuroscience, 11 (2008), 1211-1216). Since these effects are at least partly of different polarity, we investigated the combined effects of saccades and smooth pursuit on visual sensitivity. For the time course of chromatic sensitivity, we found that detection rates increased slightly around pursuit onset. During saccades to static and moving targets, detection rates dropped briefly before the saccade and reached a minimum at saccade onset. This reduction of chromatic sensitivity was present whenever a saccade was executed and it was not modified by subsequent pursuit. We also measured contrast sensitivity for flashed high- and low-spatial frequency luminance and chromatic stimuli during saccades and pursuit. During saccades, the reduction of contrast sensitivity was strongest for low-spatial frequency luminance stimuli (about 90%). However, a significant reduction was also present for chromatic stimuli (about 58%). Chromatic sensitivity was increased during smooth pursuit (about 12%). These results suggest that the modulation of visual sensitivity during saccades and smooth pursuit is more complex than previously assumed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reward anticipation and processing of social versus nonsocial stimuli in children with and without autism spectrum disorders.

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Stavropoulos, Katherine K M; Carver, Leslie J

2014-12-01

How children respond to social and nonsocial rewards has important implications for both typical and atypical social-cognitive development. Individuals with autism spectrum disorders (ASD) are thought to process rewards differently than typically developing (TD) individuals. However, there is little direct evidence to support this claim. Two event-related potentials were measured. The stimulus preceding negativity (SPN) was utilized to measure reward anticipation, and the feedback related negativity (FRN) was utilized to measure reward processing. Participants were 6- to 8-year-olds with (N = 20) and without (N = 23) ASD. Children were presented with rewards accompanied by incidental face or nonface stimuli. Nonface stimuli were composed of scrambled face elements in the shape of arrows, controlling for low-level visual properties. Children with ASD showed smaller responses while anticipating and processing rewards accompanied by social stimuli than TD children. Anticipation and processing of rewards accompanied by nonsocial stimuli was intact in children with ASD. This is the first study to measure both reward anticipation and processing in ASD while controlling for reward properties. The findings provide evidence that children with autism have reward anticipation and processing deficits for social stimuli only. Our results suggest that while typically developing children find social stimuli more salient than nonsocial stimuli, children with ASD may have the opposite preference. © 2014 The Authors. Journal of Child Psychology and Psychiatry. © 2014 Association for Child and Adolescent Mental Health.

The eye-tracking of social stimuli in patients with Rett syndrome and autism spectrum disorders: a pilot study

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José Salomão Schwartzman

2015-05-01

Full Text Available Objective To compare visual fixation at social stimuli in Rett syndrome (RT and autism spectrum disorders (ASD patients. Method Visual fixation at social stimuli was analyzed in 14 RS female patients (age range 4-30 years, 11 ASD male patients (age range 4-20 years, and 17 children with typical development (TD. Patients were exposed to three different pictures (two of human faces and one with social and non-social stimuli presented for 8 seconds each on the screen of a computer attached to an eye-tracker equipment. Results Percentage of visual fixation at social stimuli was significantly higher in the RS group compared to ASD and even to TD groups. Conclusion Visual fixation at social stimuli seems to be one more endophenotype making RS to be very different from ASD.

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

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

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Alink, Arjen; Krugliak, Alexandra; Walther, Alexander; Kriegeskorte, Nikolaus

2013-01-01

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

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

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Hill, N. J.; Schölkopf, B.

2012-04-01

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

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

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Hill, N J; Schölkopf, B

2012-01-01

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

A direct examination of the effect of intranasal administration of oxytocin on approach-avoidance motor responses to emotional stimuli.

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Angeliki Theodoridou

Full Text Available Oxytocin has been shown to promote a host of social behaviors in humans but the exact mechanisms by which it exerts its effects are unspecified. One prominent theory suggests that oxytocin increases approach and decreases avoidance to social stimuli. Another dominant theory posits that oxytocin increases the salience of social stimuli. Herein, we report a direct test of these hypotheses. In a double-blind, placebo-controlled study we examined approach-avoidance motor responses to social and non-social emotional stimuli. One hundred and twenty participants self-administered either 24 IU oxytocin or placebo and moved a lever toward or away from pictures of faces depicting emotional expressions or from natural scenes appearing before them on a computer screen. Lever movements toward stimuli decreased and movements away increased stimuli size producing the illusion that stimuli moved away from or approached participants. Reaction time data were recorded. The task produced the effects that were anticipated on the basis of the approach-avoidance literature in relation to emotional stimuli, yet the anticipated speeded approach and slowed avoidance responses to emotional faces by the oxytocin group were not observed. Interestingly, the oxytocin treatment group was faster to approach and avoid faces depicting disgust relative to the placebo group, suggesting a salience of disgust for the former group. Results also showed that within the oxytocin group women's reaction times to all emotional faces were faster than those of men, suggesting sex specific effects of oxytocin. The present findings provide the first direct evidence that intranasal oxytocin administration does not enhance approach/avoidance to social stimuli and does not exert a stronger effect on social vs. non-social stimuli in the context of processing of emotional expressions and scenes. Instead, our data suggest that oxytocin administration increases the salience of certain social stimuli

Suppression of bulboreticular unit responses to noxious stimuli by analgesic mesencephalic stimulation.

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Morrow, T J; Casey, K L

1983-01-01

The responses of 302 neurons in the medial medullary reticular formation (MRF) to a variety of noxious and innocuous somatic stimuli were studied in anesthetized and awake rats. In addition, the effects of analgesic electrical stimulation in the mesencephalon (MES) on unit responses were examined. Tail shock was the most effective stimulus, exciting more than 80% of all units recorded. This stimulus was considered separately during data analysis, since it could not be classified as noxious or innocuous. Noxious somatic stimuli (including pinch, firm pressure, pin prick, and radiant heating of the tail above 45 degrees C were especially effective in eliciting discharge in a significant fraction of all cells in both awake (123/205) and anesthetized (45/97) animals. Nociceptive neurons could be classified as nociceptive specific (NS) or wide dynamic range (WDR) depending on their responses to all somatic stimuli tested. Nociceptive neurons showed no preferential anatomical distribution. Most neurons, including those responsive to noxious inputs, exhibited large, often bilateral receptive fields which frequently covered the tail, one or more limbs, and extensive areas of the body or head. Electrical stimulation within or adjacent to the mesencephalic periaqueductal gray matter depressed the spontaneous and evoked discharge of MRF neurons in both acute and chronic preparations. This inhibition showed a significant preference (p less than 0.001, chi-square statistic) for units that were excited by somatic and especially noxious stimuli. No units were facilitated by MES stimulation. In the awake rat, unit suppression closely followed the time course and level of MES-induced analgesia. Excitability data from the acute experiments suggest that this response inhibition may be the result of a direct action on MRF neurons. Anesthesia severely depressed the spontaneous discharge of MRF neurons as well as the activity evoked by innocuous somatic stimulation. Our data suggest

Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fMRI study.

Science.gov (United States)

Dores, A R; Almeida, I; Barbosa, F; Castelo-Branco, M; Monteiro, L; Reis, M; de Sousa, L; Caldas, A Castro

2013-01-01

Examining changes in brain activation linked with emotion-inducing stimuli is essential to the study of emotions. Due to the ecological potential of techniques such as virtual reality (VR), inspection of whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images is important. The current study sought to test whether the activation of brain areas involved in the emotional processing of scenarios of different valences can be modulated by 3D. Therefore, the focus was made on the interaction effect between emotion-inducing stimuli of different emotional valences (pleasant, unpleasant and neutral valences) and visualization types (2D, 3D). However, main effects were also analyzed. The effect of emotional valence and visualization types and their interaction were analyzed through a 3 × 2 repeated measures ANOVA. Post-hoc t-tests were performed under a ROI-analysis approach. The results show increased brain activation for the 3D affective-inducing stimuli in comparison with the same stimuli in 2D scenarios, mostly in cortical and subcortical regions that are related to emotional processing, in addition to visual processing regions. This study has the potential of clarify brain mechanisms involved in the processing of emotional stimuli (scenarios' valence) and their interaction with three-dimensionality.

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

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Thompson, Ashley E; O'Sullivan, Lucia F

2012-08-01

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

Gustatory stimuli representing different perceptual qualities elicit distinct patterns of neuropeptide secretion from taste buds.

Science.gov (United States)

Geraedts, Maartje C P; Munger, Steven D

2013-04-24

Taste stimuli that evoke different perceptual qualities (e.g., sweet, umami, bitter, sour, salty) are detected by dedicated subpopulations of taste bud cells that use distinct combinations of sensory receptors and transduction molecules. Here, we report that taste stimuli also elicit unique patterns of neuropeptide secretion from taste buds that are correlated with those perceptual qualities. We measured tastant-dependent secretion of glucagon-like peptide-1 (GLP-1), glucagon, and neuropeptide Y (NPY) from circumvallate papillae of Tas1r3(+/+), Tas1r3(+/-) and Tas1r3 (-/-) mice. Isolated tongue epithelia were mounted in modified Ussing chambers, permitting apical stimulation of taste buds; secreted peptides were collected from the basal side and measured by specific ELISAs. Appetitive stimuli (sweet: glucose, sucralose; umami: monosodium glutamate; polysaccharide: Polycose) elicited GLP-1 and NPY secretion and inhibited basal glucagon secretion. Sweet and umami stimuli were ineffective in Tas1r3(-/-) mice, indicating an obligatory role for the T1R3 subunit common to the sweet and umami taste receptors. Polycose responses were unaffected by T1R3 deletion, consistent with the presence of a distinct polysaccharide taste receptor. The effects of sweet stimuli on peptide secretion also required the closing of ATP-sensitive K(+) (KATP) channels, as the KATP channel activator diazoxide inhibited the effects of glucose and sucralose on both GLP-1 and glucagon release. Both sour citric acid and salty NaCl increased NPY secretion but had no effects on GLP-1 or glucagon. Bitter denatonium showed no effects on these peptides. Together, these results suggest that taste stimuli of different perceptual qualities elicit unique patterns of neuropeptide secretion from taste buds.

The Role of Inhibition in Avoiding Distraction by Salient Stimuli.

Science.gov (United States)

Gaspelin, Nicholas; Luck, Steven J

2018-01-01

Researchers have long debated whether salient stimuli can involuntarily 'capture' visual attention. We review here evidence for a recently discovered inhibitory mechanism that may help to resolve this debate. This evidence suggests that salient stimuli naturally attempt to capture attention, but capture can be avoided if the salient stimulus is suppressed before it captures attention. Importantly, the suppression process can be more or less effective as a result of changing task demands or lapses in cognitive control. Converging evidence for the existence of this suppression mechanism comes from multiple sources, including psychophysics, eye-tracking, and event-related potentials (ERPs). We conclude that the evidence for suppression is strong, but future research will need to explore the nature and limits of this mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigating the Predictive Value of Functional MRI to Appetitive and Aversive Stimuli: A Pattern Classification Approach.

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Ciara McCabe

Full Text Available Dysfunctional neural responses to appetitive and aversive stimuli have been investigated as possible biomarkers for psychiatric disorders. However it is not clear to what degree these are separate processes across the brain or in fact overlapping systems. To help clarify this issue we used Gaussian process classifier (GPC analysis to examine appetitive and aversive processing in the brain.25 healthy controls underwent functional MRI whilst seeing pictures and receiving tastes of pleasant and unpleasant food. We applied GPCs to discriminate between the appetitive and aversive sights and tastes using functional activity patterns.The diagnostic accuracy of the GPC for the accuracy to discriminate appetitive taste from neutral condition was 86.5% (specificity = 81%, sensitivity = 92%, p = 0.001. If a participant experienced neutral taste stimuli the probability of correct classification was 92. The accuracy to discriminate aversive from neutral taste stimuli was 82.5% (specificity = 73%, sensitivity = 92%, p = 0.001 and appetitive from aversive taste stimuli was 73% (specificity = 77%, sensitivity = 69%, p = 0.001. In the sight modality, the accuracy to discriminate appetitive from neutral condition was 88.5% (specificity = 85%, sensitivity = 92%, p = 0.001, to discriminate aversive from neutral sight stimuli was 92% (specificity = 92%, sensitivity = 92%, p = 0.001, and to discriminate aversive from appetitive sight stimuli was 63.5% (specificity = 73%, sensitivity = 54%, p = 0.009.Our results demonstrate the predictive value of neurofunctional data in discriminating emotional and neutral networks of activity in the healthy human brain. It would be of interest to use pattern recognition techniques and fMRI to examine network dysfunction in the processing of appetitive, aversive and neutral stimuli in psychiatric disorders. Especially where problems with reward and punishment processing have been implicated in the pathophysiology of the disorder.

Exploring combinations of different color and facial expression stimuli for gaze-independent BCIs

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Long eChen

2016-01-01

Full Text Available AbstractBackground: Some studies have proven that a conventional visual brain computer interface (BCI based on overt attention cannot be used effectively when eye movement control is not possible. To solve this problem, a novel visual-based BCI system based on covert attention and feature attention had been proposed and was called the gaze-independent BCI. Color and shape difference between stimuli and backgrounds have generally been used in examples of gaze-independent BCIs. Recently, a new paradigm based on facial expression change had been presented, and obtained high performance. However, some facial expressions were so similar that users couldn’t tell them apart. Especially they were presented at the same position in a rapid serial visual presentation (RSVP paradigm. Consequently, the performance of BCIs is reduced.New Method: In this paper, we combined facial expressions and colors to optimize the stimuli presentation in the gaze-independent BCI. This optimized paradigm was called the colored dummy face pattern. It is suggested that different colors and facial expressions could help subjects to locate the target and evoke larger event-related potentials (ERPs. In order to evaluate the performance of this new paradigm, two other paradigms were presented, called the grey dummy face pattern and the colored ball pattern. Comparison with Existing Method(s: The key point that determined the value of the colored dummy faces stimuli in BCI systems were whether dummy face stimuli could obtain higher performance than grey faces or colored balls stimuli. Ten healthy subjects (7 male, aged 21-26 years, mean 24.5±1.25 participated in our experiment. Online and offline results of four different paradigms were obtained and comparatively analyzed.Results: The results showed that the colored dummy face pattern could evoke higher P300 and N400 ERP amplitudes, compared with the grey dummy face pattern and the colored ball pattern. Online results showed

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. Awar...

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-12-01

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

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

International Nuclear Information System (INIS)

Yoo, Ic Ryung; Ahn, Kook Jin; Lee, Jae Mun; Kim, Tae

1999-01-01

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

Healable thermoset polymer composite embedded with stimuli-responsive fibres

Science.gov (United States)

Li, Guoqiang; Meng, Harper; Hu, Jinlian

2012-01-01

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

The Lurking Snake in the Grass: Interference of Snake Stimuli in Visually Taxing Conditions

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Sandra Cristina Soares

2012-04-01

Full Text Available Based on evolutionary considerations, it was hypothesized that humans have been shaped to easily spot snakes in visually cluttered scenes that might otherwise hide camouflaged snakes. This hypothesis was tested in a visual search experiment in which I assessed automatic attention capture to evolutionarily-relevant distractor stimuli (snakes, in comparison with another animal which is also feared but where this fear has a disputed evolutionary origin (spiders, and neutral stimuli (mushrooms. Sixty participants were engaged in a task that involved the detection of a target (a bird among pictures of fruits. Unexpectedly, on some trials, a snake, a spider, or a mushroom replaced one of the fruits. The question of interest was whether the distracting stimuli slowed the reaction times for finding the target (the bird to different degrees. Perceptual load of the task was manipulated by increments in the set size (6 or 12 items on different trials. The findings showed that snake stimuli were processed preferentially, particularly under conditions where attentional resources were depleted, which reinforced the role of this evolutionarily-relevant stimulus in accessing the visual system (Isbell, 2009.

Do infants find snakes aversive? Infants' physiological responses to "fear-relevant" stimuli.

Science.gov (United States)

Thrasher, Cat; LoBue, Vanessa

2016-02-01

In the current research, we sought to measure infants' physiological responses to snakes-one of the world's most widely feared stimuli-to examine whether they find snakes aversive or merely attention grabbing. Using a similar method to DeLoache and LoBue (Developmental Science, 2009, Vol. 12, pp. 201-207), 6- to 9-month-olds watched a series of multimodal (both auditory and visual) stimuli: a video of a snake (fear-relevant) or an elephant (non-fear-relevant) paired with either a fearful or happy auditory track. We measured physiological responses to the pairs of stimuli, including startle magnitude, latency to startle, and heart rate. Results suggest that snakes capture infants' attention; infants showed the fastest startle responses and lowest average heart rate to the snakes, especially when paired with a fearful voice. Unexpectedly, they also showed significantly reduced startle magnitude during this same snake video plus fearful voice combination. The results are discussed with respect to theoretical perspectives on fear acquisition. Copyright © 2015 Elsevier Inc. All rights reserved.

Auditory Time-Frequency Masking for Spectrally and Temporally Maximally-Compact Stimuli.

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Necciari, Thibaud; Laback, Bernhard; Savel, Sophie; Ystad, Sølvi; Balazs, Peter; Meunier, Sabine; Kronland-Martinet, Richard

2016-01-01

Many audio applications perform perception-based time-frequency (TF) analysis by decomposing sounds into a set of functions with good TF localization (i.e. with a small essential support in the TF domain) using TF transforms and applying psychoacoustic models of auditory masking to the transform coefficients. To accurately predict masking interactions between coefficients, the TF properties of the model should match those of the transform. This involves having masking data for stimuli with good TF localization. However, little is known about TF masking for mathematically well-localized signals. Most existing masking studies used stimuli that are broad in time and/or frequency and few studies involved TF conditions. Consequently, the present study had two goals. The first was to collect TF masking data for well-localized stimuli in humans. Masker and target were 10-ms Gaussian-shaped sinusoids with a bandwidth of approximately one critical band. The overall pattern of results is qualitatively similar to existing data for long maskers. To facilitate implementation in audio processing algorithms, a dataset provides the measured TF masking function. The second goal was to assess the potential effect of auditory efferents on TF masking using a modeling approach. The temporal window model of masking was used to predict present and existing data in two configurations: (1) with standard model parameters (i.e. without efferents), (2) with cochlear gain reduction to simulate the activation of efferents. The ability of the model to predict the present data was quite good with the standard configuration but highly degraded with gain reduction. Conversely, the ability of the model to predict existing data for long maskers was better with than without gain reduction. Overall, the model predictions suggest that TF masking can be affected by efferent (or other) effects that reduce cochlear gain. Such effects were avoided in the experiment of this study by using maximally

Symmetric Electrode Spanning Narrows the Excitation Patterns of Partial Tripolar Stimuli in Cochlear Implants.

Science.gov (United States)

Luo, Xin; Wu, Ching-Chih

2016-12-01

In cochlear implants (CIs), standard partial tripolar (pTP) mode reduces current spread by returning a fraction of the current to two adjacent flanking electrodes within the cochlea. Symmetric electrode spanning (i.e., separating both the apical and basal return electrodes from the main electrode by one electrode) has been shown to increase the pitch of pTP stimuli, when the ratio of intracochlear return current was fixed. To explain the pitch increase caused by symmetric spanning in pTP mode, this study measured the electrical potentials of both standard and symmetrically spanned pTP stimuli on a main electrode EL8 in five CI ears using electrical field imaging (EFI). In addition, the spatial profiles of evoked compound action potentials (ECAP) and the psychophysical forward masking (PFM) patterns were also measured for both stimuli. The EFI, ECAP, and PFM patterns of a given stimulus differed in shape details, reflecting the different levels of auditory processing and different ratios of intracochlear return current across the measurement methods. Compared to the standard pTP stimuli, the symmetrically spanned pTP stimuli significantly reduced the areas under the curves of the normalized EFI and PFM patterns, without shifting the pattern peaks and centroids (both around EL8). The more focused excitation patterns with symmetric spanning may have caused the previously reported pitch increase, due to an interaction between pitch and timbre perception. Being able to reduce the spread of excitation, pTP mode symmetric spanning is a promising stimulation strategy that may further increase spectral resolution and frequency selectivity with CIs.

Temporal attention for visual food stimuli in restrained eaters

NARCIS (Netherlands)

Neimeijer, Renate A. M.; de Jong, Peter J.; Roefs, Anne

2013-01-01

Although restrained eaters try to limit their food intake, they often fail and indulge in exactly those foods that they want to avoid. A possible explanation is a temporal attentional bias for food cues. It could be that for these people food stimuli are processed relatively efficiently and require

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

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Jamie eWard

2013-10-01

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

Sensing the Worst: Neurophenomenological Perspectives on Neutral Stimuli Misperception in Schizophrenia Spectrum

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Mariateresa Sestito

2017-06-01

Full Text Available While investigating social cognitive impairments in schizophrenia, prominent evidence has been found that patients with schizophrenia show a tendency to misclassify neutral stimuli as negatively valenced. Within this population, patients presenting delusions are more prone to this phenomenon. In a previous study, Schizophrenia spectrum (SzSp patients rated positive, negative and neutral stimuli that were multimodally presented, while assessed with a checklist exploring anomalous subjective experiences and evaluated for positive and negative symptomatology. In the present work, we aimed to further explore the relationship between neutral stimuli misperception, anomalous experiences and positive/negative symptoms in SzSp patients. To this end, we adopted a dimensional approach by reconstructing from available data: (1 four a priori scales representing essential dimensions of SzSp experiential pathology following Parnas et al. (2005; and (2 five clinically meaningful factors to describe illness severity derived by Toomey et al. (1997. Results showed that although overall patients correctly recognized the target emotions, those who misinterpreted neutral auditory cues as negatively valenced also presented higher scores in Perplexity (PY, Bizarre Delusions (BD and Disorganization (Di dimensions. Moreover, a positive association between BD and both PY and Self-Disorder (SD dimensions emerged, suggesting that psychotic symptoms may be directly linked to patients’ subjectivity. In an attempt to comprehensively capture the multilayered neutral stimuli misperception phenomenon in SzSp, we aimed at bridging phenomenology and neurobiology by connecting the levels of molecular neurochemistry (i.e., altered dopaminergic neurotransmission, system neuroscience (aberrant salience of perceptual details and psychopathology (the chain involving hyper-reflexivity, self-disorders and the emergence of delusions.

Cognitive conflict increases processing of negative, task-irrelevant stimuli.

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Ligeza, Tomasz S; Wyczesany, Miroslaw

2017-10-01

The detection of cognitive conflict is thought to trigger adjustments in executive control. It has been recently shown that cognitive conflict increases processing of stimuli that are relevant to the ongoing task and that these modulations are exerted by the dorsolateral prefrontal cortex (DLPFC). However, it is still unclear whether such control influences are unspecific and might also affect the processing of task-irrelevant stimuli. The aim of the study was to examine if cognitive conflict affects processing of neutral and negative, task-irrelevant pictures. Participants responded to congruent (non-conflict) or to incongruent (conflict-eliciting) trials of a modified flanker task. Each response was followed by a presentation of a neutral or negative picture. The late positive potential (LPP) in response to picture presentation was used to assess the level of picture processing after conflict vs non-conflict trials. Connectivity between the DLPFC and attentional and perceptual areas during picture presentation was analysed to check if the DLPFC might be a source of these modulations. ERP results showed an effect of cognitive conflict only on processing of negative pictures: LPP in response to negative pictures was increased after conflict trials, whereas LPP in response to neutral pictures remained unchanged. Cortical connectivity analysis showed that conflict trials intensified information flow from the DLPFC towards attentional and perceptual regions. Results suggest that cognitive conflict increases processing of task-irrelevant stimuli; however, they must display high biological salience. Increase in cognitive control exerted by the DLPFC over attentional and perceptual regions is a probable mechanism of the effect. Copyright © 2017 Elsevier B.V. All rights reserved.

Relevance of the Irrelevant : Using Task-Irrelevant Emotional Stimuli to Test the Load-Hypothesis through ERP’s

OpenAIRE

Andersson, Per

2010-01-01

The role of attention and perceptual resources were studied in a one-back task and a letter-search task, both using the same stimuli. In the letter task, pictures were used as task-irrelevant and distracting emotional stimuli. The emotional processing of the pictures was measured through the Late Positive Potential (LPP), an event-related potential (ERP) recorded with EEG. LPP activity was significantly greater to emotional than neutral stimuli during the one-back task; this shows that emotio...

The processing of infrequently-presented low-intensity stimuli during natural sleep: An event-related potential study

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Alexandra Muller-Gass

2010-01-01

Full Text Available Event-related potentials (ERPs provide an exquisite means to measure the extent of processing of external stimuli during the sleep period. This study examines ERPs elicited by stimuli with physical characteristics akin to environmental noise encountered during sleep. Brief duration 40, 60 or 80 dB sound pressure level (SPL tones were presented either rapidly (on average every two seconds or slowly (on average every 10 seconds. The rates of presentation and intensity of the stimuli were similar to those observed in environmental studies of noise. ERPs were recorded from nine young adults during sleep and wakefulness. During wakefulness, the amplitude of an early negative ERP, N1, systematically increased as intensity level increased. A later positivity, the P3a, was apparent following the loudest 80 dB stimulus regardless of the rate of stimulus presentation; it was also apparent following the 60 dB stimulus, when stimuli were presented slowly. The appearance of the N1-P3a deflections suggests that operations of the central executive controlling ongoing cognitive activity was interrupted, forcing subjects to become aware of the obtrusive task-irrelevant stimuli. The auditory stimuli elicited very different ERP patterns during sleep. During non-rapid eye movement (NREM sleep, the ERP was characterized by an enhanced (relative to wakefulness early positivity, P2, followed by a very prominent negativity, the N350. Both deflections systematically varied in amplitude with stimulus intensity level; in addition, N350 was much larger when stimuli were presented at slow rates. The N350, a sleep-specific ERP, is thought to reflect the inhibition of processing of potentially sleep-disrupting stimulus input. During rapid eye movement (REM sleep, a small amplitude N1 was apparent in the ERP, but only for the loudest, 80 dB stimulus. A small (nonsignificant P3a-like deflection was also visible following the 80 dB stimulus, but only when stimuli were presented

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....... To investigate and compare the oral microbial profile between infants delivered vaginally and by C-section. Design. This is a cross-sectional case-control study. Eighty-four infants delivered either vaginally (n = 42) or by C-section (n = 42) were randomly selected from the 2009 birth cohort at the County...

Behavioral and neural indices of affective coloring for neutral social stimuli

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Schaefer, Stacey M; Lapate, Regina C; Schoen, Andrew J; Gresham, Lauren K; Mumford, Jeanette A; Davidson, Richard J

2018-01-01

Abstract Emotional processing often continues beyond the presentation of emotionally evocative stimuli, which can result in affective biasing or coloring of subsequently encountered events. Here, we describe neural correlates of affective coloring and examine how individual differences in affective style impact the magnitude of affective coloring. We conducted functional magnetic resonance imaging in 117 adults who passively viewed negative, neutral and positive pictures presented 2 s prior to neutral faces. Brain responses to neutral faces were modulated by the valence of preceding pictures, with greater activation for faces following negative (vs positive) pictures in the amygdala, dorsomedial and lateral prefrontal cortex, ventral visual cortices, posterior superior temporal sulcus, and angular gyrus. Three days after the magnetic resonance imaging scan, participants rated their memory and liking of previously encountered neutral faces. Individuals higher in trait positive affect and emotional reappraisal rated faces as more likable when preceded by emotionally arousing (negative or positive) pictures. In addition, greater amygdala responses to neutral faces preceded by positively valenced pictures were associated with greater memory for these faces 3 days later. Collectively, these results reveal individual differences in how emotions spill over onto the processing of unrelated social stimuli, resulting in persistent and affectively biased evaluations of such stimuli. PMID:29447377

Do Tonic Itch and Pain Stimuli Draw Attention towards Their Location?

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Antoinette I. M. van Laarhoven

2017-01-01

Full Text Available Background. Although itch and pain are distinct experiences, both are unpleasant, may demand attention, and interfere with daily activities. Research investigating the role of attention in tonic itch and pain stimuli, particularly whether attention is drawn to the stimulus location, is scarce. Methods. In the somatosensory attention task, fifty-three healthy participants were exposed to 35-second electrical itch or pain stimuli on either the left or right wrist. Participants responded as quickly as possible to visual targets appearing at the stimulated location (ipsilateral trials or the arm without stimulation (contralateral trials. During control blocks, participants performed the visual task without stimulation. Attention allocation at the itch and pain location is inferred when responses are faster ipsilaterally than contralaterally. Results. Results did not indicate that attention was directed towards or away from the itch and pain location. Notwithstanding, participants were slower during itch and pain than during control blocks. Conclusions. In contrast with our hypotheses, no indications were found for spatial attention allocation towards the somatosensory stimuli. This may relate to dynamic shifts in attention over the time course of the tonic sensations. Our secondary finding that itch and pain interfere with task performance is in-line with attention theories of bodily perception.

Stimuli-Responsive Nanodiamond-Based Biosensor for Enhanced Metastatic Tumor Site Detection.

Science.gov (United States)

Wang, Xin; Gu, Mengjie; Toh, Tan Boon; Abdullah, Nurrul Lissa Binti; Chow, Edward Kai-Hua

2018-02-01

Metastasis is often critical to cancer progression and linked to poor survival and drug resistance. Early detection of metastasis, as well as identification of metastatic tumor sites, can improve cancer patient survival. Thus, developing technology to improve the detection of cancer metastasis biomarkers can improve both diagnosis and treatment. In this study, we investigated the use of nanodiamonds to develop a stimuli-responsive metastasis detection complex that utilizes matrix metalloproteinase 9 (MMP9) as a metastasis biomarker, as MMP9 increased expression has been shown to be indicative of metastasis. The nanodiamond-MMP9 biosensor complex consists of nanodiamonds functionalized with MMP9-specific fluorescent-labeled substrate peptides. Using this design, protease activity of MMP9 can be accurately measured and correlated to MMP9 expression. The nanodiamond-MMP9 biosensor also demonstrated an enhanced ability to protect the base sensor peptide from nonspecific serum protease cleavage. This enhanced peptide stability, combined with a quantitative stimuli-responsive output function, provides strong evidence for the further development of a nanodiamond-MMP9 biosensor for metastasis site detection. More importantly, this work provides the foundation for use of nanodiamonds as a platform for stimuli-responsive biosensors and theranostic complexes that can be implemented across a wide range of biomedical applications.

Cognitive appraisal of environmental stimuli induces emotion-like states in fish.

Science.gov (United States)

Cerqueira, M; Millot, S; Castanheira, M F; Félix, A S; Silva, T; Oliveira, G A; Oliveira, C C; Martins, C I M; Oliveira, R F

2017-10-13

The occurrence of emotions in non-human animals has been the focus of debate over the years. Recently, an interest in expanding this debate to non-tetrapod vertebrates and to invertebrates has emerged. Within vertebrates, the study of emotion in teleosts is particularly interesting since they represent a divergent evolutionary radiation from that of tetrapods, and thus they provide an insight into the evolution of the biological mechanisms of emotion. We report that Sea Bream exposed to stimuli that vary according to valence (positive, negative) and salience (predictable, unpredictable) exhibit different behavioural, physiological and neuromolecular states. Since according to the dimensional theory of emotion valence and salience define a two-dimensional affective space, our data can be interpreted as evidence for the occurrence of distinctive affective states in fish corresponding to each the four quadrants of the core affective space. Moreover, the fact that the same stimuli presented in a predictable vs. unpredictable way elicited different behavioural, physiological and neuromolecular states, suggests that stimulus appraisal by the individual, rather than an intrinsic characteristic of the stimulus, has triggered the observed responses. Therefore, our data supports the occurrence of emotion-like states in fish that are regulated by the individual's perception of environmental stimuli.

Statistical modeling of the response characteristics of mechanosensitive stimuli in the human esophagus

DEFF Research Database (Denmark)

Drewes, A.M.; Reddy, H.; Staahl, C.

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....

A stimuli-responsive smart lanthanide nanocomposite for multidimensional optical recording and encryption

Energy Technology Data Exchange (ETDEWEB)

Li, Xiang; Xie, Yujie; Zhang, Hao-Li; Chen, Hao; Cai, Huijuan; Liu, Weisheng; Tang, Yu [State Key Lab. of Applied Organic Chemistry, Key Lab. of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou Univ. (China); Song, Bo [State Key Lab. of Fine Chemicals, School of Chemistry, Dalian Univ. of Technology, Dalian (China)

2017-03-01

A stimuli-responsive lanthanide-based smart nanocomposite has been fabricated by supramolecular assembly and applied as an active material in multidimensional memory materials. Conjugation of the lanthanide complexes with carbon dots provides a stimuli response that is based on the modulation of the energy level of the ligand and affords microsecond-to-nanosecond fluorescence lifetimes, giving rise to intriguing memory performance in the spatial and temporal dimension. The present study points to a new direction for the future development of multidimensional memory materials based on inorganic-organic hybrid nanosystems. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Affective Stimuli for an Auditory P300 Brain-Computer Interface

Directory of Open Access Journals (Sweden)

Akinari Onishi

2017-09-01

Full Text Available Gaze-independent brain computer interfaces (BCIs are a potential communication tool for persons with paralysis. This study applies affective auditory stimuli to investigate their effects using a P300 BCI. Fifteen able-bodied participants operated the P300 BCI, with positive and negative affective sounds (PA: a meowing cat sound, NA: a screaming cat sound. Permuted stimuli of the positive and negative affective sounds (permuted-PA, permuted-NA were also used for comparison. Electroencephalography data was collected, and offline classification accuracies were compared. We used a visual analog scale (VAS to measure positive and negative affective feelings in the participants. The mean classification accuracies were 84.7% for PA and 67.3% for permuted-PA, while the VAS scores were 58.5 for PA and −12.1 for permuted-PA. The positive affective stimulus showed significantly higher accuracy and VAS scores than the negative affective stimulus. In contrast, mean classification accuracies were 77.3% for NA and 76.0% for permuted-NA, while the VAS scores were −50.0 for NA and −39.2 for permuted NA, which are not significantly different. We determined that a positive affective stimulus with accompanying positive affective feelings significantly improved BCI accuracy. Additionally, an ALS patient achieved 90% online classification accuracy. These results suggest that affective stimuli may be useful for preparing a practical auditory BCI system for patients with disabilities.

Recent Advances in Stimuli-Responsive Release Function Drug Delivery Systems for Tumor Treatment

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Chendi Ding

2016-12-01

Full Text Available Benefiting from the development of nanotechnology, drug delivery systems (DDSs with stimuli-responsive controlled release function show great potential in clinical anti-tumor applications. By using a DDS, the harsh side effects of traditional anti-cancer drug treatments and damage to normal tissues and organs can be avoided to the greatest extent. An ideal DDS must firstly meet bio-safety standards and secondarily the efficiency-related demands of a large drug payload and controlled release function. This review highlights recent research progress on DDSs with stimuli-responsive characteristics. The first section briefly reviews the nanoscale scaffolds of DDSs, including mesoporous nanoparticles, polymers, metal-organic frameworks (MOFs, quantum dots (QDs and carbon nanotubes (CNTs. The second section presents the main types of stimuli-responsive mechanisms and classifies these into two categories: intrinsic (pH, redox state, biomolecules and extrinsic (temperature, light irradiation, magnetic field and ultrasound ones. Clinical applications of DDS, future challenges and perspectives are also mentioned.

Emotion and Attention Interaction: a trade-off between stimuli relevance, motivation and individual differences

OpenAIRE

Leticia eOliveira; Izabela eMocaiber; Isabel A David; Fatima eErthal; Eliane eVolchan; Mirtes ePereira

2013-01-01

Mounting evidence suggests that the neural processing of emotional stimuli is prioritized. However, whether the processing of emotional stimuli is dependent on attention remains debatable. Several studies have investigated this issue by testing the capacity of emotional distracters to divert processing resources from an attentional main task. The attentional load theory postulates that the perceptual load of the main task determines the selective processing of the distracter. Although we agre...

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

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

Vestibular Evoked Myogenic Potential Produced by Bone-Conducted Stimuli: A Study on its Basics and Clinical Applications in Patients with Conductive and Sensorineural Hearing Loss and a Group with Vestibular Schawannoma.

Science.gov (United States)

Mahdi, Parvane; Amali, Amin; Pourbakht, Akram; Karimi Yazdi, Alireza; Bassam, Ali

2013-06-01

Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in vestibular disorders. As it is evoked by loud sound stimulation, even mild conductive hearing loss may affect VEMP results. Bone-conducted (BC) stimulus is an alternative stimulation for evoking this response. This study aims to assess the characteristics of BC-VEMP in different groups of patients. We performed a cross sectional analysis on 20 healthy volunteers with normal pure-tone audiometry as a control group; and on a group of patients consisted of 20 participants with conductive hearing loss, five with bilateral sensorineural hearing loss and four with vestibular schawannoma. AC and BC-VEMP were performed in all participants. In control group the VEMP responses to both kinds of stimuli had an acceptable morphology and consisted of p13 and n23 waves. Latency value of these main components in each type of stimulus was not significantly different (P>0.05). However, the mean amplitude was larger in BC modality than AC stimulation (P=0.025). In the group with conductive hearing loss, the VEMP response was absent in fifteen (46.87%) of the 32 ears using the AC method, whereas all (100%) displayed positive elicitability of VEMP by BC method. Normal VEMP responses in both stimuli were evoked in all patients with sensorineural hearing loss. In patients with unilateral vestibular schwannomas (VS), 2 (50.00%) had neither AC-VEMP nor BC-VEMP. Auditory stimuli delivered by bone conduction can evoke VEMP response. These responses are of vestibular origin and can be used in vestibular evaluation of patients with conductive hearing loss.

Physiological and behavioral reactions elicited by simulated and real-life visual and acoustic helicopter stimuli in dairy goats

Science.gov (United States)

2011-01-01

Background Anecdotal reports and a few scientific publications suggest that flyovers of helicopters at low altitude may elicit fear- or anxiety-related behavioral reactions in grazing feral and farm animals. We investigated the behavioral and physiological stress reactions of five individually housed dairy goats to different acoustic and visual stimuli from helicopters and to combinations of these stimuli under controlled environmental (indoor) conditions. The visual stimuli were helicopter animations projected on a large screen in front of the enclosures of the goats. Acoustic and visual stimuli of a tractor were also presented. On the final day of the study the goats were exposed to two flyovers (altitude 50 m and 75 m) of a Chinook helicopter while grazing in a pasture. Salivary cortisol, behavior, and heart rate of the goats were registered before, during and after stimulus presentations. Results The goats reacted alert to the visual and/or acoustic stimuli that were presented in their room. They raised their heads and turned their ears forward in the direction of the stimuli. There was no statistically reliable rise of the average velocity of moving of the goats in their enclosure and no increase of the duration of moving during presentation of the stimuli. Also there was no increase in heart rate or salivary cortisol concentration during the indoor test sessions. Surprisingly, no physiological and behavioral stress responses were observed during the flyover of a Chinook at 50 m, which produced a peak noise of 110 dB. Conclusions We conclude that the behavior and physiology of goats are unaffected by brief episodes of intense, adverse visual and acoustic stimulation such as the sight and noise of overflying helicopters. The absence of a physiological stress response and of elevated emotional reactivity of goats subjected to helicopter stimuli is discussed in relation to the design and testing schedule of this study. PMID:21496239

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 ...

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.

Mirrored and rotated stimuli are not the same: A neuropsychological and lesion mapping study.

Science.gov (United States)

Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Champmartin, Cécile; Pouliquen, Dorothée; Cruypeninck, Yohann; Hannequin, Didier; Gérardin, Emmanuel

2016-05-01

Agnosia for mirrored stimuli is a rare clinical deficit. Only eight patients have been reported in the literature so far and little is known about the neural substrates of this agnosia. Using a previously developed experimental test designed to assess this agnosia, namely the Mirror and Orientation Agnosia Test (MOAT), as well as voxel-lesion symptom mapping (VLSM), we tested the hypothesis that focal brain-injured patients with right parietal damage would be impaired in the discrimination between the canonical view of a visual object and its mirrored and rotated images. Thirty-four consecutively recruited patients with a stroke involving the right or left parietal lobe have been included: twenty patients (59%) had a deficit on at least one of the six conditions of the MOAT, fourteen patients (41%) had a deficit on the mirror condition, twelve patients (35%) had a deficit on at least one the four rotated conditions and one had a truly selective agnosia for mirrored stimuli. A lesion analysis showed that discrimination of mirrored stimuli was correlated to the mesial part of the posterior superior temporal gyrus and the lateral part of the inferior parietal lobule, while discrimination of rotated stimuli was correlated to the lateral part of the posterior superior temporal gyrus and the mesial part of the inferior parietal lobule, with only a small overlap between the two. These data suggest that the right visual 'dorsal' pathway is essential for accurate perception of mirrored and rotated stimuli, with a selective cognitive process and anatomical network underlying our ability to discriminate between mirrored images, different from the process of discriminating between rotated images. Copyright © 2016 Elsevier Ltd. All rights reserved.

Promoting the use of personally relevant stimuli for investigating patients with disorders of consciousness.

Science.gov (United States)

Perrin, Fabien; Castro, Maïté; Tillmann, Barbara; Luauté, Jacques

2015-01-01

Sensory stimuli are used to evaluate and to restore cognitive functions and consciousness in patients with a disorder of consciousness (DOC) following a severe brain injury. Although sophisticated protocols can help assessing higher order cognitive functions and awareness, one major drawback is their lack of sensitivity. The aim of the present review is to show that stimulus selection is crucial for an accurate evaluation of the state of patients with disorders of consciousness as it determines the levels of processing that the patient can have with stimulation from his/her environment. The probability to observe a behavioral response or a cerebral response is increased when her/his personal history and/or her/his personal preferences are taken into account. We show that personally relevant stimuli (i.e., with emotional, autobiographical, or self-related characteristics) are associated with clearer signs of perception than are irrelevant stimuli in patients with DOC. Among personally relevant stimuli, music appears to be a promising clinical tool as it boosts perception and cognition in patients with DOC and could also serve as a prognostic tool. We suggest that the effect of music on cerebral processes in patients might reflect the music's capacity to act both on the external and internal neural networks supporting consciousness.

Promoting the use of personally-relevant stimuli for investigating patients with disorders of consciousness

Directory of Open Access Journals (Sweden)

Fabien ePerrin

2015-07-01

Full Text Available Sensory stimuli are used to evaluate and to restore cognitive functions and consciousness in patients with a disorder of consciousness (DOC following a severe brain injury. Although sophisticated protocols can help assessing higher order cognitive functions and awareness, one major drawback is their lack of sensitivity. The aim of the present review is to show that stimulus selection is crucial for an accurate evaluation of the state of patients with disorders of consciousness as it determines the levels of processing that the patient can have with stimulation from his/her environment. The probability to observe a behavioral response or a cerebral response is increased when her/his personal history and/or her/his personal preferences are taken into account. We show that personally-relevant stimuli (i.e. with emotional, autobiographical or self-related characteristics are associated with clearer signs of perception than are irrelevant stimuli in patients with DOC. Among personally-relevant stimuli, music appears to be a promising clinical tool as it boosts perception and cognition in patients with DOC and could also serve as a prognostic tool. We suggest that the effect of music on cerebral processes in patients might reflect the music’s capacity to act both on the external and internal neural networks supporting consciousness.

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.

Delivered volumes of enteral nutrition exceed prescribed volumes.

Science.gov (United States)

Walker, Renee Nichole; Utech, Anne; Velez, Maria Eugenia; Schwartz, Katie

2014-10-01

Enteral nutrition (EN) provisions are typically calculated based on a 24-hour infusion period. However, feedings are often interrupted for daily activities, procedures, or gastrointestinal intolerance. The study's objective was to determine the delivered EN quantities provided to stable hospitalized patients, using cellular time and measured volumes to verify our EN calculation adjustment. A supply of consecutively numbered ready-to-hang (RTH) EN product was delivered to the bedside of 26 inpatients with established EN tolerance at goal rates on various types of nursing units. The dietitian weighed the volume remaining in the infusing product and recorded the measurement time. On the following days, the dietitian continued to weigh the infusing RTH product and the empty RTH bottles saved by nursing. The primary outcome was the difference between the prescribed and delivered EN provisions, which was calculated with a paired t test. Patients received significantly more calories in the delivered enteral feeding (mean [SD], 1678 [385] kcal) than prescribed calories in the EN order (1489 [246 kcal]; t = 3.736, P = .001), adjusting for observed time. No significant differences were found between nursing units, product, and rate. EN delivered may actually exceed ordered amounts by 5%–21% (mean, 12%) with feeding pump inaccuracy as the primary contributing factor. This differs from what others have found. Our findings support using a volume-based ordering system vs a rate-based ordering system for more accurate EN delivery.

Advances in Application of Mechanical Stimuli in Bioreactors for Cartilage Tissue Engineering.

Science.gov (United States)

Li, Ke; Zhang, Chunqiu; Qiu, Lulu; Gao, Lilan; Zhang, Xizheng

2017-08-01

Articular cartilage (AC) is the weight-bearing tissue in diarthroses. It lacks the capacity for self-healing once there are injuries or diseases due to its avascularity. With the development of tissue engineering, repairing cartilage defects through transplantation of engineered cartilage that closely matches properties of native cartilage has become a new option for curing cartilage diseases. The main hurdle for clinical application of engineered cartilage is how to develop functional cartilage constructs for mass production in a credible way. Recently, impressive hyaline cartilage that may have the potential to provide capabilities for treating large cartilage lesions in the future has been produced in laboratories. The key to functional cartilage construction in vitro is to identify appropriate mechanical stimuli. First, they should ensure the function of metabolism because mechanical stimuli play the role of blood vessels in the metabolism of AC, for example, acquiring nutrition and removing wastes. Second, they should mimic the movement of synovial joints and produce phenotypically correct tissues to achieve the adaptive development between the micro- and macrostructure and function. In this article, we divide mechanical stimuli into three types according to forces transmitted by different media in bioreactors, namely forces transmitted through the liquid medium, solid medium, or other media, then we review and summarize the research status of bioreactors for cartilage tissue engineering (CTE), mainly focusing on the effects of diverse mechanical stimuli on engineered cartilage. Based on current researches, there are several motion patterns in knee joints; but compression, tension, shear, fluid shear, or hydrostatic pressure each only partially reflects the mechanical condition in vivo. In this study, we propose that rolling-sliding-compression load consists of various stimuli that will represent better mechanical environment in CTE. In addition, engineers

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.

Self-delivered misinformation - Merging the choice blindness and misinformation effect paradigms.

Directory of Open Access Journals (Sweden)

Lotta Stille

Full Text Available 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.

Effects of nicotine and nicotine expectancy on attentional bias for emotional stimuli.

Science.gov (United States)

Adams, Sally; Attwood, Angela S; Munafò, Marcus R

2015-06-01

Nicotine's effects on mood are thought to enhance its addictive potential. However, the mechanisms underlying the effects of nicotine on affect regulation have not been reliably demonstrated in human laboratory studies. We investigated the effects of nicotine abstinence (Experiment 1), and nicotine challenge and expectancy (Experiment 2) on attentional bias towards facial emotional stimuli differing in emotional valence. In Experiment 1, 46 nicotine-deprived smokers were randomized to either continue to abstain from smoking or to smoke immediately before testing. In Experiment 2, 96 nicotine-deprived smokers were randomized to smoke a nicotinized or denicotinized cigarette and to be told that the cigarette did or did not contain nicotine. In both experiments participants completed a visual probe task, where positively valenced (happy) and negatively valenced (sad) facial expressions were presented, together with neutral facial expressions. In Experiment 1, there was evidence of an interaction between probe location and abstinence on reaction time, indicating that abstinent smokers showed an attentional bias for neutral stimuli. In Experiment 2, there was evidence of an interaction between probe location, nicotine challenge and expectation on reaction time, indicating that smokers receiving nicotine, but told that they did not receive nicotine, showed an attentional bias for emotional stimuli. Our data suggest that nicotine abstinence appears to disrupt attentional bias towards emotional facial stimuli. These data provide support for nicotine's modulation of attentional bias as a central mechanism for maintaining affect regulation in cigarette smoking. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

More superimposition for contrast-modulated than luminance-modulated stimuli during binocular rivalry.

Science.gov (United States)

Skerswetat, Jan; Formankiewicz, Monika A; Waugh, Sarah J

2018-01-01

Luminance-modulated noise (LM) and contrast-modulated noise (CM) gratings were presented with interocularly correlated, uncorrelated and anti-correlated binary noise to investigate their contributions to mixed percepts, specifically piecemeal and superimposition, during binocular rivalry. Stimuli were sine-wave gratings of 2 c/deg presented within 2 deg circular apertures. The LM stimulus contrast was 0.1 and the CM stimulus modulation depth was 1.0, equating to approximately 5 and 7 times detection threshold, respectively. Twelve 45 s trials, per noise configuration, were carried out. Fifteen participants with normal vision indicated via button presses whether an exclusive, piecemeal or superimposed percept was seen. For all noise conditions LM stimuli generated more exclusive visibility, and lower proportions of superimposition. CM stimuli led to greater proportions and longer periods of superimposition. For both stimulus types, correlated interocular noise generated more superimposition than did anti- or uncorrelated interocular noise. No significant effect of stimulus type (LM vs CM) or noise configuration (correlated, uncorrelated, anti-correlated) on piecemeal perception was found. Exclusive visibility was greater in proportion, and perceptual changes more numerous, during binocular rivalry for CM stimuli when interocular noise was not correlated. This suggests that mutual inhibition, initiated by non-correlated noise CM gratings, occurs between neurons processing luminance noise (first-order component), as well as those processing gratings (second-order component). Therefore, first- and second-order components can contribute to overall binocular rivalry responses. We suggest the addition of a new well to the current energy landscape model for binocular rivalry that takes superimposition into account. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of aversive stimuli on prospective memory. An event-related fMRI study.

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Massimiliano Rea

Full Text Available Prospective memory (PM describes the ability to execute a previously planned action at the appropriate point in time. Although behavioral studies clearly showed that prospective memory performance is affected by the emotional significance attributed to the intended action, no study so far investigated the brain mechanisms subserving the modulatory effect of emotional salience on PM performance. The general aim of the present study was to explore brain regions involved in prospective memory processes when PM cues are associated with emotional stimuli. In particular, based on the hypothesised critical role of the prefrontal cortex in prospective memory in the presence of emotionally salient stimuli, we expected a stronger involvement of aPFC when the retrieval and execution of the intended action is cued by an aversive stimulus. To this aim BOLD responses of PM trials cued by aversive facial expressions were compared to PM trials cued by neutral facial expressions. Whole brain analysis showed that PM task cued by aversive stimuli is differentially associated with activity in the right lateral prefrontal area (BA 10 and in the left caudate nucleus. Moreover a temporal shift between the response of the caudate nucleus that preceded that of aPFC was observed. These findings suggest that the caudate nucleus might provide an early analysis of the affective properties of the stimuli, whereas the anterior lateral prefrontal cortex (BA10 would be involved in a slower and more deliberative analysis to guide goal-directed behaviour.

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

Exogenous (automatic) attention to emotional stimuli: a review

OpenAIRE

Carretié, Luis

2014-01-01

Current knowledge on the architecture of exogenous attention (also called automatic, bottom-up, or stimulus-driven attention, among other terms) has been mainly obtained from studies employing neutral, anodyne stimuli. Since, from an evolutionary perspective, exogenous attention can be understood as an adaptive tool for rapidly detecting salient events, reorienting processing resources to them, and enhancing processing mechanisms, emotional events (which are, by definition, salient for the in...

The Improvement of Dental Posture Using Personalized Biofeedback.

Science.gov (United States)

Thanathornwong, Bhornsawan; Suebnukarn, Siriwan

2015-01-01

Dentists are subject to staying in static or awkward postures for long periods due to their highly concentrated work. This study describes a real-time personalized biofeedback system developed for dental posture training with the use of vibrotactile biofeedback. The real-time personalized biofeedback system was an integrated solution that comprised of two components: 1) a wearable device that contained an accelerometer sensor for measuring the tilt angle of the body (input) and provided real-time vibrotactile biofeedback (output); and 2) software for data capturing, processing, and personalized biofeedback generation. The implementation of real-time personalized vibrotactile feedback was computed using Hidden Markov Models (HMMs). For the test case, we calculated the probability and log-likelihood of the test movements under the Work related Musculoskeletal Disorders (WMSD) and non-WMSD HMMs. The vibrotactile biofeedback was provided to the user via a wearable device for a WMSD-predicted case. In the system evaluation, a randomized crossover trial was conducted to compare dental posture measure using tilt angles of the upper back and muscle activities of those dental students that received vibrotactile biofeedback from the system with the control group against the dental students who received no feedback. The participants who received feedback from the system had a lower tilt angle at 10th, 50th, and 90th percentiles of Backx and Backy, as well as muscular load, which were statistically different (pbiofeedback system for posture training in dental students is feasible and associated with quantitative improvements of the dental posture.

Effects of propofol anesthesia on the processing of noxious stimuli in the spinal cord and the brain.

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Lichtner, Gregor; Auksztulewicz, Ryszard; Kirilina, Evgeniya; Velten, Helena; Mavrodis, Dionysios; Scheel, Michael; Blankenburg, Felix; von Dincklage, Falk

2018-05-15

Drug-induced unconsciousness is an essential component of general anesthesia, commonly attributed to attenuation of higher-order processing of external stimuli and a resulting loss of information integration capabilities of the brain. In this study, we investigated how the hypnotic drug propofol at doses comparable to those in clinical practice influences the processing of somatosensory stimuli in the spinal cord and in primary and higher-order cortices. Using nociceptive reflexes, somatosensory evoked potentials and functional magnet resonance imaging (fMRI), we found that propofol abolishes the processing of innocuous and moderate noxious stimuli at low to medium concentration levels, but that intense noxious stimuli evoked spinal and cerebral responses even during deep propofol anesthesia that caused profound electroencephalogram (EEG) burst suppression. While nociceptive reflexes and somatosensory potentials were affected only in a minor way by further increasing doses of propofol after the loss of consciousness, fMRI showed that increasing propofol concentration abolished processing of intense noxious stimuli in the insula and secondary somatosensory cortex and vastly increased processing in the frontal cortex. As the fMRI functional connectivity showed congruent changes with increasing doses of propofol - namely the temporal brain areas decreasing their connectivity with the bilateral pre-/postcentral gyri and the supplementary motor area, while connectivity of the latter with frontal areas is increased - we conclude that the changes in processing of noxious stimuli during propofol anesthesia might be related to changes in functional connectivity. Copyright © 2018 Elsevier Inc. All rights reserved.

Emotional stimuli exert parallel effects on attention and memory.

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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.

Sex differences in brain activation to emotional stimuli: a meta-analysis of neuroimaging studies.

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Stevens, Jennifer S; Hamann, Stephan

2012-06-01

Substantial sex differences in emotional responses and perception have been reported in previous psychological and psychophysiological studies. For example, women have been found to respond more strongly to negative emotional stimuli, a sex difference that has been linked to an increased risk of depression and anxiety disorders. The extent to which such sex differences are reflected in corresponding differences in regional brain activation remains a largely unresolved issue, however, in part because relatively few neuroimaging studies have addressed this issue. Here, by conducting a quantitative meta-analysis of neuroimaging studies, we were able to substantially increase statistical power to detect sex differences relative to prior studies, by combining emotion studies which explicitly examined sex differences with the much larger number of studies that examined only women or men. We used an activation likelihood estimation approach to characterize sex differences in the likelihood of regional brain activation elicited by emotional stimuli relative to non-emotional stimuli. We examined sex differences separately for negative and positive emotions, in addition to examining all emotions combined. Sex differences varied markedly between negative and positive emotion studies. The majority of sex differences favoring women were observed for negative emotion, whereas the majority of the sex differences favoring men were observed for positive emotion. This valence-specificity was particularly evident for the amygdala. For negative emotion, women exhibited greater activation than men in the left amygdala, as well as in other regions including the left thalamus, hypothalamus, mammillary bodies, left caudate, and medial prefrontal cortex. In contrast, for positive emotion, men exhibited greater activation than women in the left amygdala, as well as greater activation in other regions including the bilateral inferior frontal gyrus and right fusiform gyrus. These meta

Iconic-Memory Processing of Unfamiliar Stimuli by Retarded and Nonretarded Individuals.

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Hornstein, Henry A.; Mosley, James L.

1979-01-01

The iconic-memory processing of unfamiliar stimuli by 11 mentally retarded males (mean age 22 years) was undertaken employing a visually cued partial-report procedure and a visual masking procedure. (Author/CL)

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...... their own heartbeat and breath in the vibroacoustics of the wall and participants can swipe and knock on The Humming Wall and the vest wearer is effectively swiped and knocked upon. Our participants responded well to The Humming wall and to the Calming and Feel Good patterns....

Materials Delivered by Member States

International Nuclear Information System (INIS)

1969-01-01

In this document the Director General is reporting to the Members of the Agency, under Article IX. G of the Statute, the quantities of materials delivered by Members up to 30 June 1969 in compliance with requests the Agency had made under Article IX. D

Emotional content enhances true but not false memory for categorized stimuli.

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Choi, Hae-Yoon; Kensinger, Elizabeth A; Rajaram, Suparna

2013-04-01

Past research has shown that emotion enhances true memory, but that emotion can either increase or decrease false memory. Two theoretical possibilities-the distinctiveness of emotional stimuli and the conceptual relatedness of emotional content-have been implicated as being responsible for influencing both true and false memory for emotional content. In the present study, we sought to identify the mechanisms that underlie these mixed findings by equating the thematic relatedness of the study materials across each type of valence used (negative, positive, or neutral). In three experiments, categorically bound stimuli (e.g., funeral, pets, and office items) were used for this purpose. When the encoding task required the processing of thematic relatedness, a significant true-memory enhancement for emotional content emerged in recognition memory, but no emotional boost to false memory (exp. 1). This pattern persisted for true memory with a longer retention interval between study and test (24 h), and false recognition was reduced for emotional items (exp. 2). Finally, better recognition memory for emotional items once again emerged when the encoding task (arousal ratings) required the processing of the emotional aspect of the study items, with no emotional boost to false recognition (EXP. 3). Together, these findings suggest that when emotional and neutral stimuli are equivalently high in thematic relatedness, emotion continues to improve true memory, but it does not override other types of grouping to increase false memory.

Increasing Valid Profiles in Phallometric Assessment of Sex Offenders with Child Victims: Combining the Strengths of Audio Stimuli and Synthetic Characters.

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Marschall-Lévesque, Shawn; Rouleau, Joanne-Lucine; Renaud, Patrice

2018-02-01

Penile plethysmography (PPG) is a measure of sexual interests that relies heavily on the stimuli it uses to generate valid results. Ethical considerations surrounding the use of real images in PPG have further limited the content admissible for these stimuli. To palliate this limitation, the current study aimed to combine audio and visual stimuli by incorporating computer-generated characters to create new stimuli capable of accurately classifying sex offenders with child victims, while also increasing the number of valid profiles. Three modalities (audio, visual, and audiovisual) were compared using two groups (15 sex offenders with child victims and 15 non-offenders). Both the new visual and audiovisual stimuli resulted in a 13% increase in the number of valid profiles at 2.5 mm, when compared to the standard audio stimuli. Furthermore, the new audiovisual stimuli generated a 34% increase in penile responses. All three modalities were able to discriminate between the two groups by their responses to the adult and child stimuli. Lastly, sexual interest indices for all three modalities could accurately classify participants in their appropriate groups, as demonstrated by ROC curve analysis (i.e., audio AUC = .81, 95% CI [.60, 1.00]; visual AUC = .84, 95% CI [.66, 1.00], and audiovisual AUC = .83, 95% CI [.63, 1.00]). Results suggest that computer-generated characters allow accurate discrimination of sex offenders with child victims and can be added to already validated stimuli to increase the number of valid profiles. The implications of audiovisual stimuli using computer-generated characters and their possible use in PPG evaluations are also discussed.

[The Influence of Threatening Stimuli on the Component P200 in Patients with Paranoid Schizophrenia].

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Strelets, V B; Arkhipov, A Yu

2015-01-01

We studied schizophrenic patients with the dominance of pseudohallucinations. As is well known, pseudohallucinations are the main syndrome of schizophrenia, the so-called first rank syndrome. Pseudohallucinations are defined as a disorder of sense (affective) perception. This disorder is mainly diagnosed from the clinical picture or by pathopsychologichal observations. We investigated the evoked potentials (EP) of brain after neutral and emotionally meaningful (threatening) visual stimuli in order to specify the neurophysiological disorders of affective perception in schizophrenic patients with severe paranoid-hallucinatory syndrome who did not receive neuroleptic therapy. The analysis of P200 component in healthy subjects showed an increase in the amplitude and shortening of the latency of this wave in response to thretaning stimuli, as compared to neutral stimuli. In the group of patients with schizophrenia, the analysis showed the same increase in the level of excitation in response to emotionally threatening stimuli. However, in schizophrenic patients there were also found certain areas where the amplitude and latency decreased or increased at the same time. The results show that patients with schizophrenia have the pathological effect of having parameters typical of the processes of both excitation and inhibition.

The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference.

Science.gov (United States)

Zhang, Li; Fang, Qiaochu; Gabriel, Florence C; Szücs, Dénes

2014-01-01

Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference.

Moving Stimuli Facilitate Synchronization But Not Temporal Perception.

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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.

Heavy cannabis use and attentional avoidance of anxiety-related stimuli