Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Stimuli

  • acoustic stimulus
  • angiogenic stimulus
  • antigenic stimulus
  • apoptotic stimulus
  • auditory stimulus
  • aversive stimulus
  • blue stimulus
  • chemical stimulus
  • cold stimulus
  • complex stimulus
  • conditioned stimulus
  • conditioning stimulus
  • control stimulus
  • depolarizing stimulus
  • deviant stimulus
  • different stimulus
  • electrical stimulus
  • emotional stimulus
  • environmental stimulus
  • exogenous stimulus
  • external stimulus
  • extracellular stimulus
  • face stimulus
  • fear stimulus
  • first stimulus
  • fiscal stimulus
  • identical stimulus
  • important stimulus
  • individual stimulus
  • inflammatory stimulus
  • irrelevant stimulus
  • light stimulus
  • mechanical stimulus
  • mitogenic stimulus
  • natural stimulus
  • negative stimulus
  • neutral stimulus
  • novel stimulus
  • noxious stimulus
  • odour stimulus
  • of stimulus
  • olfactory stimulus
  • other stimulus
  • pain stimulus
  • painful stimulus
  • pathological stimulus
  • physiological stimulus
  • positive stimulus
  • potent stimulus
  • presented stimulus
  • pro-inflammatory stimulus
  • proliferative stimulus
  • provocative stimulus
  • relevant stimulus
  • repeated stimulus
  • same stimulus
  • second stimulus
  • sensory stimulus
  • single stimulus
  • social stimulus
  • specific stimulus
  • stress stimulus
  • stressful stimulus
  • strong stimulus
  • tactile stimulus
  • target stimulus
  • test stimulus
  • thermal stimulus
  • threatening stimulus
  • unconditioned stimulus
  • variety of stimulus
  • various environmental stimulus
  • various stimulus
  • verbal stimulus
  • visual stimulus

  • Terms modified by Stimuli

  • stimulus alone
  • stimulus amplitude
  • stimulus condition
  • stimulus control
  • stimulus duration
  • stimulus feature
  • stimulus frequency
  • stimulus intensity
  • stimulus level
  • stimulus material
  • stimulus modality
  • stimulus onset
  • stimulus onset asynchrony
  • stimulus package
  • stimulus parameter
  • stimulus pattern
  • stimulus presentation
  • stimulus processing
  • stimulus property
  • stimulus repetition
  • stimulus salience
  • stimulus size
  • stimulus trains
  • stimulus type
  • stimulus used

  • Selected Abstracts


    ABSTRACT Most consumers, given two identical food samples, express a preference for one, rather than choosing a no-preference option. The stability and potential causes of this seemingly irrational preference were examined across three trials under different conditions, specifically, when the first test pair was identical or different, and when participants were explicitly told that the pairs would often be identical. Choice of no preference typically increased from the first to second trial, especially for groups who saw a pair of different samples on the first trial. The explicit instruction that samples might be the same failed to reduce expressing a preference on the initial trial although it had some effect on later trials. Analysis, by individuals, of sequences of preference or no-preference responses across trials support independence of sequential responses and argue against stable personal traits as a predictor of preference choice. PRACTICAL APPLICATIONS More research needs to be done to understand the origins and operation of biases in preference tests. When tested under conditions in which the samples differ only slightly, participants tend to avoid the no-preference option. This is potentially important when interpreting the results of preference tests and assigning practical significance to their outcomes. Also, single trial testing may produce somewhat different results from multi-trial testing, the latter allowing for examination of effects of variation in recent experience. [source]

    Visual Stimuli in Daily Life

    EPILEPSIA, Issue 2004
    Dorothée G. A. Kasteleijn-Nolst Trenité
    Summary: People of all ages, but especially children and adolescents, are increasingly exposed to visual stimuli. Typical environmental stimuli that can trigger epileptic seizures in susceptible persons are televisions (TVs), computers, videogames (VGs), discothèque lights, venetian blinds, striped walls, rolling stairs (escalators), striped clothing, and sunlight reflected from snow or the sea or interrupted by trees during a ride in a car or train. Less common stimuli are rotating helicopter blades, disfunctioning fluorescent lighting, welding lights, etc. New potentially provocative devices turn up now and then unexpectedly. During the last decades especially, displays have become increasingly dominant in many of our daily-life activities. We therefore focus mainly on the characteristics of artificial light and on current and future developments in video displays and videogames. Because VG playing has been shown also to have positive effects, a rating system might be developed for provocativeness to inform consumers about the content. It is important that patients with epilepsy be informed adequately about their possible visual sensitivity. [source]

    Enhancement of steady-state auditory evoked magnetic fields in tinnitus

    Eugen Diesch
    Abstract The steady-state auditory evoked magnetic field and the Pbm, the magnetic counterpart of the second frontocentrally positive middle latency component of the transitory auditory evoked potential, were measured in ten tinnitus patients using a 122-channel gradiometer system. The patients had varying degrees of hearing loss. In all patients, the tinnitus frequency was located above the frequency of the audiometric edge, i.e. the location on the frequency axis above which hearing loss increases more rapidly. Stimuli were amplitude-modulated sinusoids with carrier frequencies at the tinnitus frequency, the audiometric edge, two frequencies below the audiometric edge, and two frequencies between the audiometric edge and the tinnitus frequency. Below the audiometric edge, the root-mean-square field amplitude of the steady-state response computed across the whole head as well as the contralateral and the ipsilateral dipole moment decreased as a function of carrier frequency. With carrier frequency above the audiometric edge, the steady-state response increased again. The amplitudes of the transitory Pbm component were patterned in a qualitatively similar way, but without the differences being significant. For the steady-state response, both whole-head root-mean-square field amplitude and the dipole moment of the sources at the tinnitus frequency showed significant positive correlations with subjective ratings of tinnitus intensity and intrusiveness. These correlations remained significant when the influence of hearing loss was partialled out. The observed steady-state response amplitude pattern likely reflects an enhanced state of excitability of the frequency region in primary auditory cortex above the audiometric edge. The relationship of tinnitus to auditory cortex hyperexcitability and its independence of hearing loss is discussed with reference to loss of surround inhibition in and map reorganization of primary auditory cortex. [source]

    Interaction between genioglossus and diaphragm responses to transcranial magnetic stimulation in awake humans

    Wei Wang
    The modulation of activity of the upper airway dilator and respiratory muscles plays a key role in the regulation of ventilation, but little is known about the link between their neuromuscular activation processes in vivo. This study investigated genioglossus and diaphragm responses to transcranial magnetic stimulation applied in different facilitatory conditions. The amplitude and latency of motor-evoked potential responses and the stimulation intensity threshold leading to a motor response (motor threshold) were recorded with stimulation applied at the vertex and anterolateral area in 13 awake normal subjects. Stimuli were applied during inspiration with and without resistance, during expiration with and without maximal tongue protrusion and during deep inspiration. In each stimulation location and condition, no diaphragmatic response was obtained without previous genioglossus activity (diaphragmatic and genioglossus responses latencies during expiration: 18.1 ± 2.9 and 6.3 ± 2.6 ms, respectively, mean ±s.d., P < 0.01). Genioglossus motor-evoked potential amplitude, latency and motor threshold were significantly modified with tongue protrusion with a maximal effect observed for stimulation in the anterolateral area. Deep inspiration was associated with a significant facilitatory effect on both genioglossus and diaphragm motor responses. The facilitatory effects of respiratory and non-respiratory manoeuvres were also observed during focal stimulation where isolated genioglossus responses were observed. Genioglossus and diaphragm differed in their motor threshold both at baseline and following facilitatory manoeuvres. Conclusions: (1) transcranial magnetic stimulation-induced genioglossus response systematically precedes that of diaphragm; (2) this sequence of activation is not modified by respiratory and non-respiratory manoeuvres; and (3) the genioglossus and diaphragm are differently influenced by these manoeuvres in terms of latency of the motor response and of motor threshold. [source]

    Seasonal resin canal formation and necroses expansion in resinous stem canker-affected Chamaecyparis obtusa

    FOREST PATHOLOGY, Issue 4-5 2002
    Summary The season of disease development on the basis of two major internal symptoms, resin canal formation and necrotic lesion expansion in phloem, were anatomically determined in Chamaecyparis obtusa (Hinoki cypress) affected by resinous stem canker. Newly formed resin canals were mostly observed at first from July to August in samples of the canker-affected C. obtusa phloem. This result indicates the occurrence of stimuli causing resin canal formation and the beginning of the formation from May to July of the same year. This and the beginning of resin exudation observed in May or June indicated that resin, exuded at least before August, originated from resin canals formed in the previous year(s). The expansion of phloem necrotic lesions began in June and continued until October, and was conspicuous in the August samples. Stimuli causing necrotic lesion development were also suggested to occur from May to August of the same year. It is hypothesized that excess resin production induces lesion development and that expansion of necrotic lesion induces both resin exudation from previously formed resin canals and new resin canal formation. The causal agent of the disease could be activated in the late spring or summer season. Résumé Formation saisonnière de canaux résinifères et extension des nécroses chez Chamaecyparis obtusa atteint par le chancre résineux du tronc Chez Chamaecyparis obtusa affecté par le chancre résineux du tronc, la saison de développement de la maladie a été déterminée anatomiquement en se basant sur deux symptômes internes majeurs: la formation de canaux résinifères et l'extension des nécroses au niveau du phloème. Des canaux résinifères récemment formés ont surtout été observés à partir de juillet et en août dans le phloème de C. obtusa atteint par la maladie. Ce résultat montre l'existence de stimuli de la formation de canaux résinifères, ceux-ci commençant à se former en mai jusqu'en juillet. Jointe au fait que l'exsudation de résine a lieu en mai ou juin, cette observation montre que la résine (au moins celle exsudée avant août) provient des canaux formés au cours de la ou des années précédentes. L'extension de la nécrose du phloème débutait en juin, était forte en août et se poursuivait jusqu'en octobre. Il est suggéré que les stimuli du développement de la nécrose ont lieu entre mai et août de la même année. Il est supposé, d'une part que la production excessive de résine induit le développement des lésions, et d'autre part que l'extension des nécroses induit l'exsudation de résine à partir des canaux antérieurement formés ainsi que la formation de nouveaux canaux. L'agent causal de la maladie pourrait être activéà la fin du printemps ou en été. Zusammenfassung Saisonale Harzkanalbildung und Entwicklung der Nekrosen bei Chamaecyparis obtusa mit ,HarzigemStammkrebs' Bei Chamaecyparis obtusa mit Befall durch den ,Harzigen Stammkrebs' wurde die Phänologie der Krankheitsentwicklung anhand der Harzkanalbildung und der Ausbreitung der Nekrosen im Phloem anatomisch erfasst. Im krebsbefallenen Phloem wurden neu gebildete Harzkanäle zuerst im Juli und August beobachtet. Dies weist darauf hin, dass die Stimulation für die Harzkanalbildung und die Entwicklung der Harzkanäle in der Zeit von Mai bis Juli des laufenden Jahres erfolgt. Diese Beobachtung und der Beginn des Harzflusses, welcher im Mai und Juni auftritt, deuten darauf hin, dass der Harzfluss vor dem August aus Harzkanälen stammt, die bereits im Vorjahr oder noch früher angelegt worden waren. Die Expansion der Phloem-Nekrosen begann im Juni und hielt bis Oktober an, im August war sie besonders stark ausgeprägt. Der Reiz für die Ausdehnung der Nekrosen dürfte somit von Mai bis August des laufenden Jahres vorhanden sein. Es wird die Hypothese aufgestellt, dass die stark gesteigerte Harzproduktion die Nekrosenentwicklung fördert und dass die Expansion der Nekrosen sowohl den Harzfluss aus den früher gebildeten Harzkanälen anregt als auch die Bildung neuer Harzkanäle induziert. Der ursächliche Faktor für diese Krankheit dürfte im späten Frühjahr oder im Sommer aktiv sein. [source]

    Amygdala,prefrontal dissociation of subliminal and supraliminal fear

    HUMAN BRAIN MAPPING, Issue 8 2006
    Leanne M. Williams
    Abstract Facial expressions of fear are universally recognized signals of potential threat. Humans may have evolved specialized neural systems for responding to fear in the absence of conscious stimulus detection. We used functional neuroimaging to establish whether the amygdala and the medial prefrontal regions to which it projects are engaged by subliminal fearful faces and whether responses to subliminal fear are distinguished from those to supraliminal fear. We also examined the time course of amygdala-medial prefrontal responses to supraliminal and subliminal fear. Stimuli were fearful and neutral baseline faces, presented under subliminal (16.7 ms and masked) or supraliminal (500 ms) conditions. Skin conductance responses (SCRs) were recorded simultaneously as an objective index of fear perception. SPM2 was used to undertake search region-of-interest (ROI) analyses for the amygdala and medial prefrontal (including anterior cingulate) cortex, and complementary whole-brain analyses. Time series data were extracted from ROIs to examine activity across early versus late phases of the experiment. SCRs and amygdala activity were enhanced in response to both subliminal and supraliminal fear perception. Time series analysis showed a trend toward greater right amygdala responses to subliminal fear, but left-sided responses to supraliminal fear. Cortically, subliminal fear was distinguished by right ventral anterior cingulate activity and supraliminal fear by dorsal anterior cingulate and medial prefrontal activity. Although subcortical amygdala activity was relatively persistent for subliminal fear, supraliminal fear showed more sustained cortical activity. The findings suggest that preverbal processing of fear may occur via a direct rostral,ventral amygdala pathway without the need for conscious surveillance, whereas elaboration of consciously attended signals of fear may rely on higher-order processing within a dorsal cortico,amygdala pathway. Hum Brain Mapp, 2005. © 2005 Wiley-Liss, Inc. [source]

    Individual Differences in Infants' Recognition of Briefly Presented Visual Stimuli

    INFANCY, Issue 3 2001
    Janet E. Frick
    Infants' recognition memory has been shown to be related to individual differences in look duration and level of heart period variability. This study examined the effect of individual differences in these 2 measures on infants' recognition of briefly presented visual stimuli using a paired-comparison recognition-memory paradigm. A sample of 35 full-term infants was studied longitudinally at 14, 20, and 26 weeks of age. Recognition memory for briefly presented stimuli was tested in 6 experimental conditions, with delays corresponding to different heart-rate-defined phases of attention. The 20-and 26-week-old infants, and infants with high levels of heart period variability, generally showed more evidence of recognition memory for briefly presented visual stimuli. Greater evidence of recognition memory was observed when stimuli were presented during sustained attention. Infants with more mature baseline physiological responses show greater evidence of recognition memory, and stimulus and procedural factors may be more important for the study of individual differences in infant visual attention than has previously been suggested. [source]

    Women's responses to fashion media images: a study of female consumers aged 30,59

    Joy M. Kozar
    Abstract The purpose of this study was to examine whether female consumers ranging in age from 30 to 59 prefer fashion advertising models more closely resembling their age. The sample for this study consisted of 182 women. Stimuli included full-colored photographs of current fashion models. A questionnaire designed to explore participants' responses to the stimuli included scales measuring participants' beliefs about the stimulus models' appearances and attractiveness, participants' purchase intentions and perceived similarity with the models and participants' perceived fashionability of the model's clothing. Participants rated models appearing older in age significantly higher than younger models on the characteristics related to appearance and attractiveness. Advertisements with older models also had a significant positive relationship to participants' purchase intentions as compared to younger-age models. Participants who perceived more similarity to the models were found to have more positive beliefs about the model's appearance and attractiveness and the fashionability of the model's clothing. Perceived similarity also had a significant positive relationship to participants' purchase intentions. As a result of this study, findings suggest that marketers and retailers should consider the age of the model used in their promotional materials. Specifically, it is possible that female consumers either transitioning into, or currently in, the middle adulthood life stages may have a preference for fashion models more closely resembling their age group. [source]

    Stimuli for nestling begging in blue tits Cyanistes caeruleus: hungry nestlings are less discriminating

    Megan Dickens
    In altricial birds, nestlings usually respond to the sound and appearance of the provisioning adults by begging for food when the adults arrive at the nest. Nestlings can, however, also beg incorrectly on hearing misleading sounds in the environment and fail to beg when the adult arrives. This study uses the blue tit Cyanistes caeruleus to test the hypotheses that nestling begging strategies are influenced by the reliability of the stimulus to beg, and that nestling motivational state affects the response to different stimuli. Here, we show experimentally that nestling hunger strongly influences the response to stimuli that vary in their reliability. While hunger increases begging rate, it also increases the likelihood that nestlings will beg when the parent is absent. This is in agreement with both the predictions of signal detection theory and recent empirical work on other species. We found, however, no evidence that age-related perceptual constraints influence the begging response of ten day old nestlings to different stimuli. [source]

    Prevention of Postmenopausal Bone Loss by a Low-Magnitude, High-Frequency Mechanical Stimuli: A Clinical Trial Assessing Compliance, Efficacy, and Safety,

    Clinton Rubin
    Abstract A 1-year prospective, randomized, double-blind, and placebo-controlled trial of 70 postmenopausal women demonstrated that brief periods (<20 minutes) of a low-level (0.2g, 30 Hz) vibration applied during quiet standing can effectively inhibit bone loss in the spine and femur, with efficacy increasing significantly with greater compliance, particularly in those subjects with lower body mass. Introduction: Indicative of the anabolic potential of mechanical stimuli, animal models have demonstrated that short periods (<30 minutes) of low-magnitude vibration (<0.3g), applied at a relatively high frequency (20,90 Hz), will increase the number and width of trabeculae, as well as enhance stiffness and strength of cancellous bone. Here, a 1-year prospective, randomized, double-blind, and placebo-controlled clinical trial in 70 women, 3,8 years past the menopause, examined the ability of such high-frequency, low-magnitude mechanical signals to inhibit bone loss in the human. Materials and Methods: Each day, one-half of the subjects were exposed to short-duration (two 10-minute treatments/day), low-magnitude (2.0 m/s2 peak to peak), 30-Hz vertical accelerations (vibration), whereas the other half stood for the same duration on placebo devices. DXA was used to measure BMD at the spine, hip, and distal radius at baseline, and 3, 6, and 12 months. Fifty-six women completed the 1-year treatment. Results and Conclusions: The detection threshold of the study design failed to show any changes in bone density using an intention-to-treat analysis for either the placebo or treatment group. Regression analysis on the a priori study group demonstrated a significant effect of compliance on efficacy of the intervention, particularly at the lumbar spine (p = 0.004). Posthoc testing was used to assist in identifying various subgroups that may have benefited from this treatment modality. Evaluating those in the highest quartile of compliance (86% compliant), placebo subjects lost 2.13% in the femoral neck over 1 year, whereas treatment was associated with a gain of 0.04%, reflecting a 2.17% relative benefit of treatment (p = 0.06). In the spine, the 1.6% decrease observed over 1 year in the placebo group was reduced to a 0.10% loss in the active group, indicating a 1.5% relative benefit of treatment (p = 0.09). Considering the interdependence of weight, the spine of lighter women (<65 kg), who were in the highest quartile of compliance, exhibited a relative benefit of active treatment of 3.35% greater BMD over 1 year (p = 0.009); for the mean compliance group, a 2.73% relative benefit in BMD was found (p = 0.02). These preliminary results indicate the potential for a noninvasive, mechanically mediated intervention for osteoporosis. This non-pharmacologic approach represents a physiologically based means of inhibiting the decline in BMD that follows menopause, perhaps most effectively in the spine of lighter women who are in the greatest need of intervention. [source]

    Interactions Between Extracellular Stimuli and Excitation Waves in an Atrial Reentrant Loop

    Introduction: The interactions between extracellular stimuli and excitation waves propagating in a reentrant loop are a complex function of stimulus parameters, structural properties, membrane state, and timing. Here the goal was a comprehensive understanding of the mechanisms and frequencies of the major interactions between the advancing excitation wave and a single extracellular stimulus, separated from issues of anatomic or geometric complexity. Methods and Results: A modernized computer model of a thin ring of uniform tissue that included a pair of extracellular stimulus electrodes (anode/cathode) was used to model one-dimensional cardiac reentry. Questions and results included the following: (1) What are the major interactions between a stimulus and the reentrant propagation wave, and are they induced near the cathode or near the anode; and, for each interaction, what are the initiating amplitude range and timing interval? At the cathode, the well-known mechanism of retrograde excitation terminated reentry; changes in timing or amplitude produced double-wave reentry or phase reset. At the anode, termination occurred at different cells depending on stimulus amplitude. (2) Relatively how often did termination occur at the anode? For most stimulus amplitudes, termination occurred more often at the anode than at the cathode, although not always at the same cell. (3) With random timing, what is the probability of terminating reentry? Stimulation for 5 msec terminated reentry with a probability from 0% to approximately 10%, as a function of increasing stimulus amplitude. Conclusion: A single extracellular stimulus can initiate major changes in reentrant excitation via multiple mechanisms, even in a simple geometry. Termination of reentry, phase shifts, or double-wave reentry each occurs over well-defined ranges of stimulus amplitude and timing. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***-***, October 2003) [source]

    Development of letter position processing: effects of age and orthographic transparency

    Maria Ktori
    This study investigated the relative extent to which developing readers (6- and 9-year-olds) of English (deep) or Greek (transparent) orthography exhibit serial and exterior letter effects in letter position encoding. Participants were given a visual search task that required detection of a pre-specified target letter within a random five-letter string. Stimuli comprised letters either specific to English or Greek, or shared by both orthographies. For native letters, all readers showed significant initial-letter facilitation. In contrast, final-letter facilitation was shown only by English children. Furthermore, Greek 9-year-olds showed significantly more left-to-right facilitation than English 9-year-olds. These results suggest that letter position encoding is adaptive to the nature of the orthography acquired during reading development. [source]

    Avoidance of Alcohol-Related Stimuli in Alcohol-Dependent Inpatients

    ALCOHOLISM, Issue 8 2007
    J. M. Townshend
    Background: Previous research has shown an attentional bias toward drug-related stimuli in heavy social drinkers. Attentional orientation to drug-related cues may lead to increased craving and preoccupation with the drug and impaired ability to focus attention on nondrug-related activities, resulting in renewed drug taking or relapse from drug abstinence. Objective: The aim of this study was to investigate whether alcohol-dependent inpatients would differ in their selective attention toward alcohol-related stimuli in comparison with a group of social drinking controls. Method: Thirty-five alcohol-dependent inpatients were compared with a group of 39 social drinking controls matched for age, sex, and verbal IQ. Attentional bias was assessed using alcohol-related pictures in a dot probe detection task. Questionnaires were used to examine outcome expectancies after alcohol consumption, anxiety, mood, and craving. Results: The alcoholic inpatients showed a bias away from the alcohol-related stimuli, scored higher on alcohol outcome expectancies, and on anxiety measures (both state and trait). They also presented with more negative mood compared with the control group. Craving was higher in the alcoholic group for the factor "loss of control over drinking." Conclusions: Alcoholic inpatients undergoing treatment based on the 12-step treatment of Alcoholics Anonymous (Minnesota model), which includes counseling, and intensive group, individual, and family psychotherapy, show an avoidance for drug-related stimuli and a perception of loss of control over drinking. We suggest that their increased perception of loss of control over drinking produces the avoidance from the drug-related stimuli. [source]


    ABSTRACT A trained panel of 19 subjects were asked to rate a number of sensory attributes of commercially available vanilla custard desserts. Stimuli were placed in plastic cups and were sampled using 11-mm-diameter straws. In total, 304 samples were weighed before and after sampling and the volume ingested was calculated. The subjects were categorized into two groups on the basis of the mean volume ingested per sample (< and >10.6 mL). There were significant differences in the ratings between the two groups for temperature, creamy, astringent, melting and airy mouthfeels and rough and fatty after-feel. We suggest that in sensory testing, it is important to either control or measure bite size to reduce intersubject variability. Manufacturers and caterers may also be able to modify the perception of their products by providing cues to the appropriate bite size by controlling the size of the spoon or container provided. [source]

    Long-Lasting Resistance to Extinction of Response Reinstatement Induced by Ethanol-Related Stimuli: Role of Genetic Ethanol Preference

    ALCOHOLISM, Issue 10 2001
    Roberto Ciccocioppo
    Background: The conditioning of ethanol's reinforcing effects with specific environmental stimuli is thought to be a critical factor in long-lasting relapse risk associated with alcoholism. To study the significance of such learning factors in the addictive potential of ethanol, this experiment was designed (1) to characterize the effects of stimuli associated with alcohol availability on the reinstatement of responding at a previously ethanol-paired lever in rats with genetically determined ethanol preference versus nonpreference and (2) to examine the persistence of the motivating effects of these stimuli over time. Methods: Male alcohol-preferring (P) and alcohol-nonpreferring (NP) rats were trained to operantly self-administer ethanol (10% w/v) or water on a fixed-ratio 1 schedule in a 30-min daily session. Ethanol and water sessions were scheduled in random sequence across training days. Ethanol availability was signaled by an olfactory discriminative stimulus (banana extract, S+), and each lever press was paired with brief presentation of the conditioning chamber's house light (CS+). The discriminative stimulus signaling water availability (i.e., nonreward) consisted of anise odor (S,), and lever-responses during water sessions were paired with a brief white noise generation (CS,). The rats then were placed on extinction conditions during which ethanol and water, as well as the corresponding stimuli, were withheld. The effects of noncontingent exposure to the S+ versus S, paired with response-contingent presentation of the CS+ versus CS, on responding at the previously active lever were then determined in 30-min reinstatement sessions. To study the resistance to extinction of the effects of the ethanol-associated stimuli, additional tests were conducted at 3-day intervals for a total of 50 days. Results: The number of ethanol-reinforced responses during self-administration training was significantly greater in P than in NP rats (p < 0.01). After extinction, a significant recovery of responding was observed in both groups of rats under the stimulus conditions associated with ethanol (S+/CS+) but not those associated with water (S,/CS,). However, the response reinstatement was significantly greater in P than NP rats (p < 0.01). In addition, the results revealed a considerable resistance to extinction to the effects of the ethanol-associated stimuli. Throughout the 50-day test period, responding remained significantly above extinction levels in both P and NP rats (p < 0.01), but with an overall greater number of responses in P than NP rats (p < 0.05). Conclusions: The results support the hypothesis that conditioning factors contribute importantly to compulsive ethanol seeking and long-lasting vulnerability to relapse. In addition, the results suggest that genetic predisposition toward heightened ethanol intake extends to greater susceptibility to the motivating effects of ethanol-related environmental stimuli. [source]

    Deficits of temporal discrimination in dystonia are independent from the spatial distance between the loci of tactile stimulation

    MOVEMENT DISORDERS, Issue 2 2002
    Michele Tinazzi MD
    Abstract To assess whether spatial variables influence deficits of temporal somesthetic discrimination in dystonic patients, 10 patients with idiopathic dystonia and 12 healthy controls were tested with pairs of non-noxious electrical stimuli separated by different time intervals. Stimuli were delivered: (1) to the pad of the index finger (same-point condition), (2) to the pad and to the base of the index finger (same-finger condition), and (3) to the pad of the index and ring fingers (different-finger condition). Subjects were asked to report whether they perceived single or double stimuli in the first condition and synchronous or asynchronous stimuli in the second and third conditions. Somesthetic temporal discrimination thresholds (STDTs) were obtained by computing the shortest time interval at which stimuli, applied to the left or the right hand, were perceived as separate in the first condition or asynchronous in the second and third conditions. STDTs were significantly higher in dystonic patients than controls in all three conditions. In both dystonia patients and controls, STDTs resulted highest in conditions whereby stimuli were maximally separated in space. Results extend current knowledge of deficits of somesthetic temporal discrimination in dystonia by showing that temporal deficits are not influenced by spatial variables. © 2002 Movement Disorder Society. [source]

    Corneal mechanical sensitivity measurement using a staircase technique

    Blanka Golebiowski
    Abstract Purpose:, To determine the repeatability of an unequal staircase technique (Garcia-Perez Staircase, GPS) to measure corneal mechanical threshold using the CRCERT-Belmonte Aesthesiometer, and to compare this with a previously-reported psychophysical method (Method of Constant Stimuli, MOCS). Methods:, The GPS, utilising unequal ascending and descending steps, was used to obtain a threshold measurement from the mean of six response reversals. Repeatability was determined for the GPS and MOCS methods (n = 14), and threshold results obtained with each method were compared (n = 10). Results:, The GPS (65.0 ± 16.9 mL min,1; CoR ± 18.3 mL min,1) method was more repeatable than the MOCS (64.0 ± 15.7 mL min,1; CoR ± 37.3 mL min,1) and the absolute values obtained with the two methods were not significantly different. Conclusions:, Although each method gave equivalent threshold results, the GPS method was more repeatable and quicker to apply and hence should reduce the influence of patient fatigue and help to minimise possible carry-over effects. [source]

    Iris color and age-related changes in lens optical density,

    Billy R. Hammond Jr.
    Summary Purpose: Epidemiologic evidence indicates that dark iris color increases risk of age-related cataract. No information is currently available, however, on the effects of iris color on the lens prior to cataract development. In this study, we relate iris color to lens optical density (OD) in individuals without frank cataract. Methods: 90 subjects with blue or green irises (light color) were compared with 87 subjects having hazel, brown, or black irises (dark color). Lens OD was measured psychophysically by comparing scotopic thresholds obtained at 410 (measuring) and 550 nm (reference). Stimuli were presented in Maxwellian view. Results: The groups with light and with dark iris color did not differ significantly in smoking habits, dietary patterns, or age. Despite other similarities between the groups, lens OD was significantly(p<0.024) higher in the group with dark irises. The higher OD of the dark iris group was due to differences in the older subjects (>45 years,p<0.005), rather than the younger subjects (20,45 years) who showed no differences in lens OD. Conclusion: Our data indicate that iris pigmentation may be directly related to age-associated increases in lens OD. [source]

    Hearing of note: An electrophysiologic and psychoacoustic comparison of pitch discrimination between vocal and instrumental musicians

    PSYCHOPHYSIOLOGY, Issue 6 2008
    Dee A. Nikjeh
    Abstract Cortical auditory evoked potentials of instrumental musicians suggest that music expertise modifies pitch processing, yet less is known about vocal musicians. Mismatch negativity (MMN) to pitch deviances and difference limen for frequency (DLF) were examined among 61 young adult women, including 20 vocalists, 21 instrumentalists, and 20 nonmusicians. Stimuli were harmonic tone complexes from the mid-female vocal range (C4,G4). MMN was elicited by multideviant paradigm. DLF was obtained by an adaptive psychophysical paradigm. Musicians detected pitch changes earlier and DLFs were 50% smaller than nonmusicians. Both vocal and instrumental musicians possess superior sensory-memory representations for acoustic parameters. Vocal musicians with instrumental training appear to have an auditory neural advantage over instrumental or vocal only musicians. An incidental finding reveals P3a as a sensitive index of music expertise. [source]

    Attentional blink modulation during sustained and after discrete lead stimuli presented in three sensory modalities

    PSYCHOPHYSIOLOGY, Issue 2 2003
    Ottmar V. Lipp
    Abstract Previous studies found larger attentional modulation of acoustic blinks during task-relevant than during task-irrelevant acoustic or visual, but not tactile, lead stimuli. Moreover, blink modulation was larger overall during acoustic lead stimuli. The present experiment investigated whether these results reflect modality specificity of attentional blink modulation or effects of continuous stimulation. Participants performed a discrimination and counting task with acoustic, visual, or tactile lead stimuli. Stimuli were presented sustained or consisted of two short discrete stimuli. The sustained condition replicated previous results. In the discrete condition, blinks were larger during task-relevant than during task-irrelevant stimuli in all groups regardless of lead stimulus modality. Thus, previous results that seemed consistent with modality-specific accounts of attentional blink modulation reflect effects of continuous stimulus input. [source]

    Monitoring asthma therapy using indirect bronchial provocation tests,

    John D. Brannan
    Abstract Objectives:, Bronchial provocation tests that assess airway hyperresponsiveness (AHR) are known to be useful in assisting the diagnosis of asthma and in monitoring inhaled corticosteroid therapy. We reviewed the use of bronchial provocation tests that use stimuli that act indirectly for monitoring the benefits of inhaled corticosteroids. Data Source:, Published clinical trials investigating the effect of inhaled corticosteroids on bronchial hyperresponsiveness in persons with asthma were used for this review. Study Selection:, Studies using indirect stimuli to provoke airway narrowing such as exercise, eucapnic voluntary hyperventilation, cold air hyperventilation, hypertonic saline, mannitol, or adenosine monophosphate (AMP) to assess the effect of inhaled corticosteroids were selected. Results:, Stimuli acting indirectly result in the release of a variety of bronchoconstricting mediators such as leukotrienes, prostaglandins, and histamine, from cells such as mast cells and eosinophils. A positive response to indirect stimuli is suggestive of active inflammation and AHR that is consistent with a diagnosis of asthma. Persons with a positive response to indirect stimuli benefit from daily treatment with inhaled corticosteroids. Symptoms and lung function are not useful to predict the long-term success of inhaled corticosteroid dose as they usually resolve rapidly, and well before inflammation and AHR has resolved. Following treatment, AHR to indirect stimuli is attenuated. Further, during long-term treatment, asthmatics can become as non-responsive as non-asthmatic healthy persons, suggesting that asthma is not active. Conclusions:, Non-responsiveness to indirect bronchial provocation tests following inhaled corticosteroids occurs weeks to months following the resolution of symptoms and lung function. Non-responsiveness to indirect stimuli may provide a goal for adequate therapy with inhaled corticosteroids. Please cite this paper as: Brannan JD, Koskela H and Anderson SD. Monitoring asthma therapy using indirect bronchial provocation tests. The Clinical Respiratory Journal 2007;1:3,15. [source]

    Theological Stimuli from the Migrant Churches

    Christine Lienemann-Perrin
    First page of article [source]

    Attributing Social Meaning to Ambiguous Visual Stimuli in Higher-functioning Autism and Asperger Syndrome: The Social Attribution Task

    Ami Klin
    More able individuals with autism and Asperger syndrome (AS) have been shown to pass relatively high level theory of mind (ToM) tasks without displaying commensurate levels of social adaptation in naturalistic settings. This paper presents a social cognitive procedure,the Social Attribution Task (SAT),that reduces factors thought to facilitate ToM task performance without facilitating real-life social functioning. Sixty participants with autism (N= 20), AS (N= 20), and normally developing adolescents and adults (N= 20) with normative IQs were asked to provide narratives describing Heider and Simmel's (1944) silent cartoon animation in which geometric shapes enact a social plot. These narratives were coded in terms of the participants' abilities to attribute social meaning to the geometric cartoon. The SAT provides reliable and quantified scores on seven indices of social cognition. Results revealed marked deficits in both clinical groups across all indices. These deficits were not related to verbal IQ or level of metalinguistic skills. Individuals with autism and AS identified about a quarter of the social elements in the story, a third of their attributions were irrelevant to the social plot, and they used pertinent ToM terms very infrequently. They were also unable to derive psychologically based personality features from the shapes' movements. When provided with more explicit verbal information on the nature of the cartoon, individuals with AS improved their performance slightly more than those with autism, but not significantly so. [source]

    1141638491 Hepatocyte growth factor (HGF) stimulates mammalian target of rapamycin (mTOR) in choriocarcinoma cell lines and human trophoblast cells

    S Busch
    Introduction:, Hepatocyte growth factor (HGF), interleukin-6 (IL-6) and insulin-like growth factor-II (IGF-II) are involved in the regulation of trophoblast cell migration and invasion. Signal Transducer and Activator of Transcription 3 (STAT3) and Mammalian Target Of Rapamycin (mTOR) signalling regulate cell invasion, growth and proliferation. mTOR plays also a key role during embryogenesis. Knock-out mice embryos die after implantation and blastocysts trophoblast outgrowth is reduced. Aim:, Stimuli which might trigger such invasive behaviour through mTOR should be defined. Methods:, The human choriocarcinoma cell lines JEG-3, JAR, the human choriocarcinoma-trophoblast hybrid AC1-M59 and human term trophoblast cells were stimulated with HGF, IL-6 or IGF-II. At several time points, the phosphorylation level of mTOR and STAT3 were tested by Western blot. STAT3 DNA-binding capacity was analyzed by Electrophorectic Mobility Shift Assay (EMSA). To examine the role of mTOR for invasion and proliferation, mTOR expression was silenced by RNA interference (RNAi). Results:, HGF, IGF-II and IL-6 did neither induce tyrosine (705) phosphorylation of STAT3 nor STAT3 DNA binding capacity as assessed by EMSA. HGF led to an increase of mTOR serine (2448) phosphorylation for all cell types after 15 and 30 min while IL-6 and IGF-II did not induce mTOR phosphorylation. Simultaneously, HGF decreased STAT3 serine (727) phosphorylation. mTOR silencing in AC1-M59 correlates with reduced proliferation and invasion. STAT3 expression was not affected by mTOR knock down. Conclusion:, HGF triggers mTOR activity in trophoblast and trophoblast-like cells. mTOR is a main regulator of crucial trophoblast functions. [source]

    Antigenic as Well as Nonantigenic Stimuli Induce Similar Middle Ear Responses in the Rat,

    THE LARYNGOSCOPE, Issue 2 2003
    Edith L. G. M. Tonnaer MSc
    Abstract Objectives/Hypothesis The observation that during otitis media many different types of micro-organisms have been cultured from effusions indicate that, once present in the middle ear cavity, most types of micro-organisms are able to trigger an inflammatory reaction leading to otitis media. The present study was designed to determine the middle ear response after injection of different substances into the middle ear cavity. Study Design To determine whether and to what extent an inflammatory response of the middle ear depends on the entering agent, the response in the tympanic cavity was studied by otomicroscopy and histological examination after inoculation of various substances. Methods Lewis rats were inoculated in transtympanic fashion either with live or heat-killed bacteria (pathogenic and nonpathogenic), Keyhole limpet hemocyanin, active charcoal, or saline. The mucosal response of the challenged middle ears was studied histologically. Results Irrespective of the inoculated substance, no essential differences in the mucosal response were found. The intensity of the inflammatory response was greater when live bacteria were inoculated. Conclusions The present study demonstrates that any substance reaching the middle ear cavity is likely to induce otitis media. These observations emphasize the role of the eustachian tube as "porte d'entrée" in the pathogenesis of this disorder. Determination of specific aspects of the eustachian tube involved in protection or in facilitating bacterial translocation will be important for the understanding of the pathogenesis of otitis media and the subsequent development of new therapeutic strategies. In addition, elucidation of bacterial factors involved in the process of colonization and translocation will be of equal importance. [source]

    Using Visual Stimuli in Ethnography

    George Spindler
    In this article, the work of George and Louise Spindler is reviewed with visual stimuli ranging from the Rorschach technique and Thematic Apperception Technique to inventions of their own, the Cross-Cultural Sensitization Technique, the Instrumental Activities Inventory, and the Cross-Cultural, Comparative, Reflective Interview Technique. The sites of the various researches, the methods of application, and a brief analysis of the results are included.,[interview techniques, culture and personality, ethnography and education] [source]

    Different Stimuli Reduce Attraction to Pollinators in Male and Female Figs in the Dioecious Fig Ficus hispida

    BIOTROPICA, Issue 6 2009
    Hao-Yuan Hu
    ABSTRACT Fig trees (Ficus) and their obligate pollinating wasps (Hymenoptera, Chalcidoidea, Agaonidae) are a classic example of a coevolved mutualism. Pollinating wasps are attracted to figs only when figs are receptive. It has been shown that figs will lose their attraction to pollinators sooner in monoecious and male dioecious figs when multiple pollinators have entered the enclosed inflorescence. However, little is known about the nature of the stimulus inducing the loss of attraction. By conducting experiments on the functionally dioecious fig, Ficus hispida, we show that (1) different stimuli induce the loss of attraction in each sex, pollination in female figs, and oviposition in male figs; and (2) foundress number affects the loss of attraction in both sexes only when the prerequisites (i.e., pollination in female figs and oviposition in male figs) have been satisfied. In general, the more foundresses that enter, the earlier the fig will lose its receptivity. We argue that the stimuli in male and female figs are adaptations to the fulfillment of its respective reproduction. [source]

    Optimal stimulus size maps in the primary visual cortex revealed by optical imaging in cats

    Purpose: It is well known that the responses of cells in the primary visual cortex depend on stimulus size. While the stimulus-size dependency has been well documented at the cellular level, nothing is known about its consequences on global functional maps. Methods: Optical imaging of intrinsic signals in the primary visual cortex was carried out in anesthetized cats. Stimuli consisted of 0.75 to 0.1 cycles per degree square-wave gratings drifting in 8 directions at 2 to 4 Hz and were presented monocularly. Responses were obtained for different stimulus diameters (3 to 50 deg, and a full screen condition). Results: The minimal visual stimulation necessary to activate areas 17 and 18 was around 3 and 6 deg. in diameter respectively. The activation area of cortex (10-30 mm2) was dependent of the eccentricity (0 to 30 deg). The pixelwise measure of the signal magnitude in this area showed a modular organisation uncorrelated with the orientation map and stable in time: Half of the pixels had a maximum activation for the full screen stimulation (full field facilitation) and the other half attained their maximum for diameters about 15 and 30 deg of diameter in area 17 and 18 respectively (full field suppression). The suppression by the full screen stimulation was around 30% in both areas. Conclusions: Thus, the maximum activation revealed by optical imaging necessitates the stimulation of a much larger spatial area than that observed with single cells. This difference is likely due to the fact that this method reflects in- and out going signals and reveals activity of adjacent neurons being part of intra-cortical and thalamo-cortical circuits. Supp: NSERC and CIHR. [source]

    Synthetic Molecular Machine Based on Reversible End-to-Interior and End-to-End Loop Formation Triggered by Electrochemical Stimuli

    CHEMISTRY - AN ASIAN JOURNAL, Issue 8-9 2008
    Jae Wook Lee Dr.
    Abstract We have designed and synthesized a novel [2]pseudorotaxane-based molecular machine in which the interconversion between end-to-interior and end-to-end loop structures is reversibly controlled by electrochemical stimuli. Cucurbit[8]uril (CB[8]) and the thread molecule 34+ with an electron-rich hydroxynaphthalene unit and two electron-deficient viologen units form the 1:1 complex 44+ with an end-to-interior loop structure, which is reversibly converted into an end-to-end structure upon reduction. Large changes in shape and size of the molecule accompany the reversible redox process. The key feature of the machine-like behavior is the reversible interconversion between an intramolecular charge-transfer complex and viologen cation radical dimer inside CB[8] triggered by electrochemical stimuli. [source]

    Infants' Attention to Patterned Stimuli: Developmental Change From 3 to 12 Months of Age

    CHILD DEVELOPMENT, Issue 3 2006
    Mary L. Courage
    To examine the development of look duration as a function of age and stimulus type, 14- to 52-week-old infants were shown static and dynamic versions of faces, Sesame Street material, and achromatic patterns for 20 s of accumulated looking. Heart rate was recorded during looking and parsed into stimulus orienting, sustained attention, and attention termination phases. Infants' peak look durations indicated that prior to 26 weeks there was a linear decrease with age for all stimuli. Older infants' look durations continued to decline for patterns but increased for Sesame Street and faces. Measures of heart rate change during sustained attention and the proportion of time spent in each phase of attention confirmed infants' greater engagement with the more complex stimuli. [source]