Search results for "Visual Perception"

2016

Mirror training therapy is a promising tool to initiate neural plasticity and facilitate the recovery process of motor skills after diseases such as stroke or hemiparesis by improving the intermanual transfer of fine motor skills in healthy people as well as in patients. This study evaluated whether these augmented performance improvements by mirror visual feedback (MVF) could be used for learning a sport-specific skill and if the effects are modulated by skill level. A sample of 39 young, healthy, and experienced basketball and handball players and 41 novices performed a stationary basketball dribble task at a mirror box in a standing position and received either MVF or direct feedback. Af…

Indicadores tempranos (0-36 meses) de riesgo de trastorno del espectro autista. Un estudio de revisión.

2018

La prevalencia del trastorno del espectro autista (TEA) ha aumentado de manera muy notable en los últimos años debido fundamentalmente a un aumento del conocimiento sobre el mismo por parte de los profesionales responsables de su identificación y/o diagnóstico.El presente trabajo tiene como objetivo realizar una revisión de los artículos publicados en 2018 que se han propuesto identificar entre los 0 y 36 meses de vida predictores fiables de la posterior aparición del TEA.Se realizó una búsqueda en PsycInfo en la que se localizaron 8 estudios empíricos diseñados para evaluar el poder predictivo de estos indicadores tempranos.En estos estudios se identificaron diferentes síntomas que se cons…

Application of Supervised Machine Learning for Behavioral Biomarkers of Autism Spectrum Disorder Based on Electrodermal Activity and Virtual Reality

2020

[EN] Objective: Sensory processing is the ability to capture, elaborate, and integrate information through the five senses and is impaired in over 90% of children with autism spectrum disorder (ASD). The ASD population shows hyper¿hypo sensitiveness to sensory stimuli that can generate alteration in information processing, affecting cognitive and social responses to daily life situations. Structured and semi-structured interviews are generally used for ASD assessment, and the evaluation relies on the examiner¿s subjectivity and expertise, which can lead to misleading outcomes. Recently, there has been a growing need for more objective, reliable, and valid diagnostic measures, such as biomar…

Visual and postural eye-height information is flexibly coupled in the perception of virtual environments.

2021

We conducted two experiments to investigate how observers integrate postural and visual eye-height information when estimating the layout of interior space. In Experiment 1, we varied postural and visual eye-height information independently of each other in a virtual-reality setup. Observers estimated the width, depth, and height of simulated rooms. All dimensions were perceived as larger when the virtual visual eye-height corresponded to sitting on the floor as compared with standing upright. In contrast, the estimates remained widely unaffected by the observer's physical posture (likewise sitting vs. standing). In Experiment 2, we studied effects of the viewing condition (real vs. virtual…

Cortical and subcortical visual event-related potentials to oddball stimuli in rabbits

2000

We applied repetitive transcranial magnetic stimulation (rTMS) in order to induce interference on visuo-spatial perception in 11 healthy subjects. Subjects performed a visuo-spatial task requiring judgements about the symmetry of prebisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 50 ms on a computer-monitor. Performance was examined in basal condition and during rTMS trains of 10 stimuli at 25 Hz, delivered through a focal coil over right or left posterior parietal cortex (P5 and P6 sites) and triggered synchronously with visual stimulus. Randomly intermixed sham rTMS trains were employed to control for non-speci…

Voluntary and Involuntary Attention in Bistable Visual Perception: A MEG Study

2020

In this study, voluntary and involuntary visual attention focused on different interpretations of a bistable image, were investigated using magnetoencephalography (MEG). A Necker cube with sinusoidally modulated pixels' intensity in the front and rear faces with frequencies 6.67 Hz (60/9) and 8.57 Hz (60/7), respectively, was presented to 12 healthy volunteers, who interpreted the cube as either left- or right-oriented. The tags of these frequencies and their second harmonics were identified in the average Fourier spectra of the MEG data recorded from the visual cortex. In the first part of the experiment, the subjects were asked to voluntarily control their attention by interpreting the cu…

Effects of rectilinear acceleration and optokinetic and caloric stimulations in space.

1984

During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight. The most significant result was that caloric mystagmus of the same direction as on the earth could also be evoked in the weightless environment.

Mapping of the human visual cortex using image-guided transcranial magnetic stimulation

2002

We describe a protocol using transcranial magnetic stimulation (TMS) to systematically map the visual sensations induced by focal and non-invasive stimulation of the human occipital cortex. TMS is applied with a figure of eight coil to 28 positions arranged in a 2x2-cm grid over the occipital area. A digitizing tablet connected to a PC computer running customized software, and audio and video recording are used for detailed and accurate data collection and analysis of evoked phosphenes. A frameless image-guided neuronavigational device is used to describe the position of the actual sites of the stimulation coils relative to the cortical surface. Our results show that TMS is able to elicit p…

All Eyes on Me : Behaving as Soloist in Duo Performances Leads to Increased Body Movements and Attracts Observers’ Visual Attention

2020

Duo musicians exhibit a broad variety of bodily gestures, but it is unclear how soloists’ and accompanists’ movements differ and to what extent they attract observers’ visual attention. In Experiment 1, seven musical duos’ body movements were tracked while they performed two pieces in two different conditions. In a congruent condition, soloist and accompanist behaved according to their expected musical roles; in an incongruent condition, the soloist behaved as accompanist and vice versa. Results revealed that behaving as soloist, regardless of the condition, led to more, smoother, and faster head and shoulder movements over a larger area than behaving as accompanist. Moreover, accompanists …

Artificial faces predict gaze allocation in complex dynamic scenes

2019

Both low-level physical saliency and social information, as presented by human heads or bodies, are known to drive gaze behavior in free-viewing tasks. Researchers have previously made use of a great variety of face stimuli, ranging from photographs of real humans to schematic faces, frequently without systematically differentiating between the two. In the current study, we used a Generalized Linear Mixed Model (GLMM) approach to investigate to what extent schematic artificial faces can predict gaze when they are presented alone or in competition with real human faces. Relative differences in predictive power became apparent, while GLMMs suggest substantial effects for real and artificial f…