Search results for "Photic stimulation"
showing 10 items of 307 documents
Limitations of concurrently representing objects within view and in visual working memory
2020
AbstractRepresenting visibly present stimuli is as limited in capacity as representing invisible stimuli in visual working memory (WM). In this study, we explored whether concurrently representing stimuli within view affects representing objects in visual WM, and if so, whether this effect is modulated by the storage states (active and silent state) of memory contents? In experiment 1, participants were asked to perform the change-detect task in a simultaneous-representing condition in which WM content and the continuously-visible stimuli in view were simultaneously represented, as well as a baseline condition in which only the representations of visual WM content were maintained. The resul…
Recognition memory for single items and for associations in amnesic patients
2004
Recognition memory performance reflects two distinct processes or types of memory referred to as recollection and familiarity. According to theoretical claims about the two types of memory, single item and associative recognition tasks can be used as an experimental method to distinguish recollection and familiarity processes. Associative recognition decisions can be used as an index of recollection while memory for single items is mostly based on familiarity judgement. We employed this procedure to examine a possible dissociation in the memory performance of amnesic patients between spared single item and impaired associative recognition. Twelve amnesic patients, six with damage confined t…
The Auditory Kuleshov Effect: Multisensory Integration in Movie Editing
2016
Almost a hundred years ago, the Russian filmmaker Lev Kuleshov conducted his now famous editing experiment in which different objects were added to a given film scene featuring a neutral face. It is said that the audience interpreted the unchanged facial expression as a function of the added object (e.g., an added soup made the face express hunger). This interaction effect has been dubbed “Kuleshov effect.” In the current study, we explored the role of sound in the evaluation of facial expressions in films. Thirty participants watched different clips of faces that were intercut with neutral scenes, featuring either happy music, sad music, or no music at all. This was crossed with the facia…
Allocentric time-to-contact and the devastating effect of perspective
2014
AbstractWith regard to impending object–object collisions, observers may use different sources of information to judge time to contact (tC). We introduced changes of the observer’s vantage point to test among three sets of hypotheses: (1) Observers may use a distance-divided-by-velocity algorithm or, alternatively, elaborated τ-formulae, all of which give exact tC information; (2) observers may use simple τ-formulae (i.e., formulae of the type: visual angle divided by its own first temporal derivative); (3) observers may capitalize on non-τ variables. Hypotheses (2) and (3) imply specific patterns of errors. We presented animated, impending collisions between a moving object and a stationar…
The big picture: effects of surround on immersion and size perception.
2014
Despite the fear of the entertainment industry that illegal downloads of films might ruin their business, going to the movies continues to be a popular leisure activity. One reason why people prefer to watch movies in cinemas may be the surround of the movie screen or its physically huge size. To disentangle the factors that might contribute to the size impression, we tested several measures of subjective size and immersion in different viewing environments. For this purpose we built a model cinema that provided visual angle information comparable with that of a real cinema. Subjects watched identical movie clips in a real cinema, a model cinema, and on a display monitor in isolation. Wher…
Pointing to double-step visual stimuli from a standing position: very short latency (express) corrections are observed in upper and lower limbs and m…
2010
How fast can we correct a planned movement following an unexpected target jump? Subjects, starting in an upright standing position, were required to point to a target that randomly and unexpectedly jumps forward to a constant spatial location. Rapid motor corrections in the upper and lower limbs, with latency responses of less than 100 ms, were revealed by contrasting electromyographic activities in perturbed and unperturbed trials. The earliest responses were observed primarily in the anterior section of the deltoidus anterior (shoulder) and the tibialis anterior (leg) muscles. Our findings indicate that visual on-going movement corrections may be accomplished via fast loops at the level o…
Modulation of premotor mirror neuron activity during observation of unpredictable grasping movements.
2004
Using transcranial magnetic stimulation, we explored the properties of premotor mirror neurons during the passive observation of a reaching-grasping movement in human subjects. Two different experiments were run using video-clips as visual stimuli. Video-clips showed a normally performed (control stimulus) or an anomalous reaching-grasping movement executed by delaying the time of the appearance of the maximal finger aperture (experiment 1), or substituting it with an unpredictable closure (experiment 2). Motor evoked potentials were recorded at different time-points during the observation of the video-clips. Profiles of cortical excitability were drawn and compared with the kinematic profi…
Release of premotor activity after repetitive transcranial magnetic stimulation of prefrontal cortex
2008
In the present study we aimed to explore by means of repetitive transcranial magnetic stimulation (rTMS) the reciprocal influences between prefrontal cortex (PFC) and premotor cortex (PMC). Subjects were asked to observe on a computer monitor different pictures representing manipulations of different kind of tools. They had to produce a movement (go condition) or to keep the resting position (no-go condition) at the appearance of different cue signals represented by different colors shown alternatively on the hands manipulating the tools or on the picture background. Motor evoked potentials (MEPs) were collected at the offset of the visual stimuli before and after a 10 minute, 1 Hz rTMS tra…
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…
1 Hz rTMS enhances extrastriate cortex activity in migraine
2003
We recently reported a paradoxical facilitatory effect of 1 Hz repetitive TMS (rTMS) on the primary visual cortex in migraine possibly due to the failure of inhibitory circuits, unable to be upregulated by low frequency rTMS. To investigate if inhibitory circuit dysfunction extends beyond striate cortex in migraine with aura, we studied the effects of 1 Hz rTMS over the right extrastriate cortex on perception of illusory contours in these patients. Low-frequency rTMS enhanced activity of extrastriate cortex in migraineurs, speeding up reaction times on illusory contour perception. This finding supports the view of a failure of inhibitory circuits also involving the extrastriate cortex in mi…