Search results for "Cues"
showing 10 items of 465 documents
Immediate transfer of synesthesia to a novel inducer.
2009
In synesthesia, a certain stimulus (e.g. grapheme) is associated automatically and consistently with a stable perceptual-like experience (e.g. color). These associations are acquired in early childhood and remain robust throughout the lifetime. Synesthetic associations can transfer to novel inducers in adulthood as one learns a second language that uses another writing system. However, it is not known how long this transfer takes. We found that grapheme-color associations can transfer to novel graphemes after only a 10-minute writing exercise. Most subjects experienced synesthetic associations immediately after learning a new Glagolitic grapheme. Using a Stroop task, we provide objective ev…
Repetition and form priming interact with neighborhood density at a brief stimulus onset asynchrony.
2001
The relationships between repetition- and form-priming effects and neighborhood density were analyzed in two masked priming experiments with the lexical decision task. Given that form-priming effects appear to be influenced by a word's orthographic neighborhood, it is theoretically important to find out whether repetition priming also differs as a function of the word's orthographic neighborhood. Within an activation framework, repetition- and form-priming effects are just quantitatively different phenomena, whereas the two effects are qualitatively different in a serial-ordered model of lexical access (the entry-opening model). The results show that repetition- and form-priming effects wer…
Neural Mechanisms of Placebo Anxiolysis
2015
The beneficial effects of placebo treatments on fear and anxiety (placebo anxiolysis) are well known from clinical practice, and there is strong evidence indicating a contribution of treatment expectations to the efficacy of anxiolytic drugs. Although clinically highly relevant, the neural mechanisms underlying placebo anxiolysis are poorly understood. In two studies in humans, we tested whether the administration of an inactive treatment along with verbal suggestions of anxiolysis can attenuate experimentally induced states of phasic fear and/or sustained anxiety. Phasic fear is the response to a well defined threat and includes attentional focusing on the source of threat and concomitant …
The human brain processes visual changes that are not cued by attended auditory stimulation.
2004
Event-related potentials (ERPs) to visual stimuli were recorded from the scalp of eight adult humans performing a task in which they counted vowels from a heard story. In the oddball condition, a repeated (standard) light bar of 50 ms in duration was rarely (P = 0.1) replaced by a (deviant) one differing in orientation from the standard. In the control condition, standards were simply omitted from the series and only (alone-) deviants retained. In both conditions, visual stimuli were asynchronous with auditory-task-relevant stimuli. ERPs to deviants significantly differed in amplitude from those to standards in the midline electrodes centrally, parietally and occipitally at 160-200 ms from …
Quantifying the Wollaston Illusion
2020
In the early 19th century, William H. Wollaston impressed the Royal Society of London with engravings of portraits. He manipulated facial features, such as the nose, and thereby dramatically changed the perceived gaze direction, although the eye region with iris and eye socket had remained unaltered. This Wollaston illusion has been replicated numerous times but never with the original stimuli. We took the eyes (pupil and iris) from Wollaston’s most prominent engraving and measured their perceived gaze direction in an analog fashion. We then systematically added facial features (eye socket, eyebrows, nose, skull, and hair). These features had the power to divert perceived gaze direction by…
Who is looking at me? The cone of gaze widens in social phobia
2011
Gaze direction is an important cue that regulates social interactions and facilitates joint attention. Although humans are very accurate in determining gaze directions in general, they have a surprisingly liberal criterion for the presence of mutual gaze. Using an established psychophysical task that required observers to adjust the eyes of a virtual head to the margins of the area of mutual gaze, we examined whether the resulting cone of gaze is altered in people with social phobia. It turned out that during presence of a second virtual person, the gaze cone's width was specifically enlarged in patients with social phobia as compared to healthy controls. The size of this effect was correla…
Timing flickers across sensory modalities
2009
In tasks requiring a comparison of the duration of a reference and a test visual cue, the spatial position of test cue is likely to be implicitly coded, providing a form of a congruency effect or introducing a response bias according to the environmental scale or its vectorial reference. The precise mechanism generating these perceptual shifts in subjective duration is not understood, although several studies suggest that spatial attentional factors may play a critical role. Here we use a duration comparison task within and across sensory modalities to examine if temporal performance is also modulated when people are exposed to spatial distractors involving different sensory modalities. Di…
Excitability of subcortical motor circuits in Go/noGo and forced choice reaction time tasks
2006
The size of the response to a startling auditory stimulus (SAS) may reflect the excitability of the reticulospinal tract. In this study, we examined whether there was any excitability change in the reticulospinal tract during preparation for execution of two types of choice reaction time task: a forced choice reaction time task (fCRT) and a Go/no-Go task (GnG). In 13 healthy volunteers we used three types of trials: control trials in which subjects were requested to perform ballistic wrist movements during fCRT or GnG tasks; test trials in which a SAS was presented with the visual cue, and baseline trials in which SAS was presented alone. Latency and area of the responses to SAS were measur…
Human eyes do not need monochromatic aberrations for dynamic accommodation
2017
Purpose To determine if human accommodation uses the eye's own monochromatic aberrations to track dynamic accommodative stimuli. Methods Wavefront aberrations were measured while subjects monocularly viewed a monochromatic Maltese cross moving sinusoidally around 2D of accommodative demand with 1D amplitude at 0.2 Hz. The amplitude and phase (delay) of the accommodation response were compared to the actual vergence of the stimulus to obtain gain and temporal phase, calculated from wavefront aberrations recorded over time during experimental trials. The tested conditions were as follows: Correction of all the subject's aberrations except defocus (C); Correction of all the subject's aberratio…
Enhancing effects of acute psychosocial stress on priming of non-declarative memory in healthy young adults.
2011
Social stress affects cognitive processes in general, and memory performance in particular. However, the direction of these effects has not been clearly established, as it depends on several factors. Our aim was to determine the impact of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity to psychosocial stress on short-term non-declarative memory and declarative memory performance. Fifty-two young participants (18 men, 34 women) were subjected to the Trier Social Stress Task (TSST) and a control condition in a crossover design. Implicit memory was assessed by a priming test, and explicit memory was assessed by the Rey Auditory Verbal Learning Test…