Search results for "Stimulus"
showing 10 items of 555 documents
Transient and sustained BOLD signal time courses affect the detection of emotion-related brain activation in fMRI.
2014
A tremendous amount of effort has been dedicated to unravel the functional neuroanatomy of the processing and regulation of emotion, resulting in a well-described picture of limbic, para-limbic and prefrontal regions involved. Studies applying functional magnetic resonance imaging (fMRI) often use the block-wise presentation of stimuli with affective content, and conventionally model brain activation as a function of stimulus or task duration. However, there is increasing evidence that regional brain responses may not always translate to task duration and rather show stimulus onset-related transient time courses. We assume that brain regions showing transient responses cannot be detected in…
Does the proportion of associatively related pairs modulate the associative priming effect at very brief stimulus-onset asynchronies?
2002
A number of experiments have shown that the magnitude of the associative priming effect increases substantially when there is a high proportion of associatively related pairs in the list when the stimulus-onset asynchrony (SOA) between prime and target is long (more than 400 ms). In the present series of experiments we manipulated the proportion of associatively related pairs when the SOA was very brief (less than 200 ms). If processing of a target word is facilitated automatically by the prior presentation of a related prime, the occurrence of priming should be unaffected by the proportion of related pairs in the list. Experiment 1 showed a robust relatedness proportion effect obtained in …
The influence of temporal factors on automatic priming and conscious expectancy in a simple reaction time task.
2009
In a previous study, we reported a dissociation between subjective expectancy and motor behaviour in a simple associative learning task (Perruchet, Cleeremans, & Destrebecqz, 2006). According to previous conditioning studies (Clark, Manns, & Squire, 2001), this dissociation is observed when the to-be-associated events coterminate and thus overlap in time (a training regimen called delay conditioning), but not when they are separated by a temporal delay (trace conditioning). In this latter situation indeed, there tends to be a direct relationship between subjective expectancy and behaviour. In this study, we further investigated this issue in a series of experiments where conscious …
GH responses to two consecutive bouts of neuromuscular electrical stimulation in healthy adults.
2008
BackgroundIt is well established that repeated GHRH administration or repeated voluntary exercise bouts are associated with a complete blunting of GH responsiveness when the administration of the second stimulus follows the first one after a 2-h interval.AimTo evaluate GH responses to neuromuscular electrical stimulation (NMES) in healthy adults.MethodsSix volunteers (mean age±s.d. 31.7±5.5 years) were studied before and after two consecutive bouts of NMES exercise (a series of 20 contractions at the maximum of individual tolerance, frequency: 75 Hz, pulse duration: 400 μs, on–off ratio: 6.25–20 s) administered at a 2-h interval.ResultsBaseline GH levels (mean: 0.3±0.2 ng/ml) significantly …
From the Big Five to the General Factor of Personality: a Dynamic Approach
2014
AbstractAn integrating and dynamic model of personality that allows predicting the response of the basic factors of personality, such as the Big Five Factors (B5F) or the general factor of personality (GFP) to acute doses of drug is presented in this paper. Personality has a dynamic nature, i.e., as a consequence of a stimulus, the GFP dynamics as well as each one of the B5F of personality dynamics can be explained by the same model (a system of three coupled differential equations). From this invariance hypothesis, a partial differential equation, whose solution relates the GFP with each one of the B5F, is deduced. From this dynamic approach, a co-evolution of the GFP and each one of the B…
Size invariance in visual number discrimination
1991
This study deals with the observer's ability to discriminate the numerosity of two random dot-patterns irrespective of their relative size. One of these two patterns was a reference one that was always composed of 32 dots randomly distributed within a K x K invisible square window (K = 1.92 degrees). The second one was the test pattern with one of the five magnifications (K = 0.64 degrees, 1.28 degrees, 1.92 degrees, 2.56 degrees, 3.20 degrees) and the relative number of dots varied on 11 levels (N = -15, -12, -9, -6, -3, 0, 3, 6, 9, 12, or 15 dots). The observer's task was to indicate which of the two patterns contained more dots. The results show that the stimulus size, as an irrelevant s…
Inhibitory control pathway to disinhibited eating: A matter of perspective?
2018
Abstract Recent studies highlight the importance of disinhibited eating and underlying inhibitory control deficits in the maintenance of obesity. So far, inhibition facets have been examined in isolation and findings are inconsistent due to different measures. This study illustrates the multifaceted nature of inhibitory control by comparing different inhibition stages in outpatients with chronic overweight (with binge eating disorder, BED, n = 24; Non-BED, n = 47) and healthy controls (HC, n = 30). Besides reporting impulsive patterns (UPPS), participants performed the Food Stroop (FST), Door Opening (DOT) and Stop Signal (SST) task with food and generic stimuli. The results showed a signif…
Working memory capacity affects trade-off between quality and quantity only when stimulus exposure duration is sufficient : Evidence for the two-phas…
2019
AbstractThe relation between visual working memory (VWM) capacity and attention has attracted much interest. In this study, we investigated the correlation between the participants’ VWM capacity and their ability to voluntarily trade off the precision and number of items remembered. The two-phase resource allocation model proposed by Ye et al. (2017) suggests that for a given set size, it takes a certain amount of consolidation time for an individual to control attention to adjust the VWM resources to trade off the precision and number. To verify whether trade-off ability varies across VWM capacity, we measured each individual’s VWM capacity and then conducted a colour recall task to examin…
Intra and inter-raters reliability and agreement of stimulus electrodiagnostic tests with two different electrodes in sedated critically-ill patients
2019
Objective: The aim of the present study was to verify the intra- and inter-rater reliability and agreement of the stimulus electrodiagnostic test (SET) measurements obtained by pen and square elect...
Dynamic accommodation without feedback does not respond to isolated blur cues
2016
Highlights • A new methodology is used to study a potential cue for dynamic accommodation. • We show that human accommodation is not driven correctly by defocus alone. • Accommodation is most efficient using changes in stimulus vergence with feedback.