Search results for "Sensor"

2021

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 can be thought of as head orientation attracting perceived gaze direction when the eye region is unchanged. In naturalistic viewing, the eye region changes with head orientation and typically produces a repulsion effect. Here we explore if there is a flip side to the illusion. Does the gaze direction also alter the perceived direction of the head? We used copies of the …

Neuropsychological Approaches to Visually-Induced Vection: an Overview and Evaluation of Neuroimaging and Neurophysiological Studies

2020

Abstract Moving visual stimuli can elicit the sensation of self-motion in stationary observers, a phenomenon commonly referred to as vection. Despite the long history of vection research, the neuro-cognitive processes underlying vection have only recently gained increasing attention. Various neuropsychological techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) have been used to investigate the temporal and spatial characteristics of the neuro-cognitive processing during vection in healthy participants. These neuropsychological studies allow for the identification of different neuro-cognitive correlates of vection, which (a) will help to unravel …

Multivariate EEG spectral analysis evidences the functional link between motor and visual cortex during integrative sensorimotor tasks

2012

The identification of the networks connecting brain areas and the understanding of their role in executing complex tasks is a crucial issue in cognitive neuroscience. In this study, specific visuomotor tasks were devised to reveal the functional network underlying the cooperation process between visual and motor regions. Electroencephalography (EEG) data were recorded from twelve healthy subjects during a combined visuomotor task, which integrated precise grip motor commands with sensory visual feedback (VM). This condition was compared with control tasks involving pure motor action (M), pure visual perception (V) and visuomotor performance without feedback (V + M). Multivariate parametric …

Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

2019

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real f…

Suppression of extinction with TMS in humans: from healthy controls to patients.

2006

We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …

Panel Summary: Plasticity and Reconfigurability in Sensory Systems

1997

Natural neural network are highly plastic in structure and function and may adapt to long lasting environmental changes. Plasticity and adaptation are not confined to lower level of processing, or to lower vertebrates, but also at the higher levels of visual processing in higher vertebrates are highly dynamic and perform considerable spatial integration. There are numerous influences that play a role in the functional architecture of the retina and the, cortex, the dynamics of the outside environment, the context within which a feature is presented, the history of previous visual stimulation and attention or expectation. The brief report on the visual system is integrated by the report of G…

Attention Direction in Static and Animated Diagrams

2010

Two key requirements for comprehending a diagram are to parse it into appropriate components and to establish relevant relationships between those components. These requirements can be particularly demanding when the diagram is complex and the viewers are novices in the depicted domain. Lack of domain-specific knowledge for top-down guidance of visual attention prejudices novices' extraction of task-relevant information. Static diagrams designed for novices often include visual cues intended to improve such information extraction. However, because current approaches to cueing tend to be largely intuitive, their effectiveness can be questionable. Further, animated diagrams with their percept…

2015

Previewing distracters enhances the efficiency of visual search. Watson and Humphreys (1997) proposed that the preview benefit rests on visual marking, a mechanism which actively encodes distracter locations at preview and inhibits them afterwards at search. As Watson and Humphreys did, we used a letter-color search task to study constraints of visual marking in conjunction search and near-efficient single-feature search with single-colored and homogeneous distracter letters. Search performance was measured for fixed target and distracter features (block design) and for randomly changed features across trials (random design). In single-feature search there was a full preview benefit for bot…

Chapter 7 - Sensory interactions in wine: effect of nonvolatile molecules on wine aroma and volatiles on Taste/Astringency perception

2012

International audience; It is widely accepted that sensory interactions can, and do, occur during wine consumption. To this concern, many studies have dealt with aroma-taste interactions which have been attributed to physicochemical interactions in the product itself, interactions at the receptor level or cognitive interactions. Although the understanding of these interactions has grown during last years and it has been demonstrated that they are strongly product-dependent, investigations have seldom gone beyond that of model solutions with a reduced number of components (volatile and/or nonvolatile molecules). Recently some investigations carried out in this field have been conducted with …

Problems in Precise Measurement of Tidal Volumes

1998

Respiratory gas flows and volumes can conveniently be measured by pneumo-tachography.3 However, the pneumotachographic signal depends on gas temperature, humidity, and composition, and therefore the achievable precision of measurement is limited to about 5–10%2,8 — which is not sufficient for determining the human ventilation distribution with satisfactory accuracy.6,7,5 As a — potentially more accurate — alternative, a plethysmographic method may be used in which the tested subject breathes out of and into bags that are suspended in a large tank of constant volume (Figure 1). Volume V and pressure P in the system (consisting of tank, tubings, valves, and the subject) are related via Boyle-…