In sensory biology, a major outstanding question is how sensory receptor cells minimize noise while maximizing signal to set the detection threshold. This optimization could be problematic because the origin of both the signals and the limiting noise in most sensory systems is believed to lie in stimulus transduction. Signal processing in receptor cells can improve the signal‐to‐noise ratio. However, neural circuits can further optimize the detection threshold by pooling signals from sensory receptor cells and processing them using (...) a combination of linear and nonlinear filtering mechanisms. In the visual system, noise limiting light detection has been assumed to arise from stimulus transduction in rod photoreceptors. In this context, the evolutionary optimization of the signal‐to‐noise ratio in the retina has proven critical in allowing visual sensitivity to approach the limits set by the quantal nature of light. Here, we discuss how noise in the mammalian retina is mitigated to allow for highly sensitive night vision. (shrink)

The dominant view of the ventral and dorsal visual systems is that they subserve perception and action. De Wit, Van der Kamp, and Masters suggested that a more fundamental distinction might exist between the nature of information exploited by the systems. The present study distinguished between these accounts by asking participants to perform delayed matching , pointing and perceptual judgment responses to masked Müller–Lyer stimuli of varying length. Matching and pointing responses of participants who could not perceptually judge stimulus (...) length at brief durations remained sensitive to veridical stimulus length , but not the illusion , which was effective at long durations. Distinct thresholds for egocentric and allocentric information pick up were thus evident irrespective of whether perception or action responses were required. It was concluded that the dorsal and ventral systems may be delineated fundamentally by fast egocentric- and slower allocentric information pick up, respectively. (shrink)

We experience our own body through both touch and vision. We further see that others’ bodies are similar to our own body, but we have no direct experience of touch on others’ bodies. Therefore, relations between vision and touch are important for the sense of self and for mental representation of one’s own body. For example, seeing the hand improves tactile acuity on the hand, compared to seeing a non-hand object. While several studies have demonstrated this visual enhancement of (...) touch effect, its relation to the ‘bodily self’, or mental representation of one’s own body remains unclear. We examined whether VET is an effect of seeing a hand, or of seeing my hand, using the rubber hand illusion. In this illusion, a prosthetic hand which is brushed synchronously—but not asynchronously—with one’s own hand is felt to actually be one’s hand. Thus, we manipulated whether or not participants felt like they were looking directly at their hand, while holding the actual stimulus they viewed constant. Tactile acuity was measured by having participants judge the orientation of square-wave gratings. Two characteristic effects of VET were observed: cross-modal enhancement from seeing the hand was inversely related to overall tactile acuity, and participants near sensory threshold showed significant improvement following synchronous stroking, compared to asynchronous stroking or no stroking at all. These results demonstrate a clear functional relation between the bodily self and basic tactile perception. (shrink)

Some patients with damaged striate cortex have blindsight-the ability to discriminate unseen stimuli in their clinically blind visual field defects when forced-choice procedures are used. Blindsight implies a sharp dissociation between visual performance and visual awareness, but signal detection theory indicates that it might be indistinguishable from the behavior of normal subjects near the lower limit of conscious vision, where the dissociations could arise trivially from using different response criteria during clinical and forced-choice tests. We tested the (...) latter possibility with a hemianopic subject during yes-no and forced-choice detection of static and moving targets. His response criterion differed significantly between yes-no and forced-choice responding, and the difference was sufficient to produce a blindsight-like dissociation with bias-sensitive measures of performance. When measured independently of bias, his sensitivity to static targets was greater in the forced-choice than in the yes-no task (unlike normal control subjects), but his sensitivity to moving targets did not differ. Differences in response criterion could therefore account for dissociations between yes-no and forced-choice detection of motion, but not of static pattern. The results explain why patients with blindsight are apparently more often ''aware'' of moving stimuli than of static stimuli. However, they also imply that blindsight is unlike normal vision near threshold, and that pattern- and motion-detection in blindsight may depend on different sets of neural mechanisms during yes-no and forced-choice tests. (shrink)

Blindsight is the term commonly used to describe visually guided behaviour elicited by a stimulus falling within the scotoma (blind area) caused by a lesion of the striate cortex. Such is normally held to be unconscious and to be mediated by subcortical pathways involving the superior colliculus. Blindsight is of considerable theoretical importance since it suggests that destriate man is more like destriate monkey than had been previously believed and also because it supports the classical notion of two visual (...) systems. It is also of potential clinical importance, since it has been claimed recently that systematic practice in blindsight can lead to the recovery of normal visual function in patients with cortical lesions. From a review of the literature it is concluded that all of the phenomena of blindsight can be attributed either to light scatter into unimpaired parts of the visual field or to residual vision resulting from spared striate cortex. The possible contribution f other factors is also considered. It is concluded that blindsight studies have generally failed to control for such nonblindsight interpretations partly because of poor methodology and partly because of difficulties in defining the term. (shrink)

Sensation is the reflection of the brain on the individual attributes of objective things that directly act on the sense organs. Feeling is the most elementary cognitive process and the simplest psychological phenomenon. Vision is a kind of sense, and sense is produced by objective things acting on the sense organs. But at present, it is rare to analyze interior design exhibition from the perspective of visual psychology, an emerging science, as an interdisciplinary attempt, only in interior design research. (...) Therefore, the study of sensory process should start from its external stimuli, in order to first understand how it acts on the sensory organs to produce sensory phenomena. This paper mainly studies the visual performance of psychological factors in interior design under the background of artificial intelligence. This paper proposes a K-means clustering algorithm and a localization algorithm fused with visual and inertial navigation. The distance thresholds corresponding to the SIFT feature descriptors of threshold T1, 128D, 96D, 64D, and 32D are 170, 160, 150, and 90, respectively. This verifies that the candidate image with the highest number of matching points is considered the best matching image. (shrink)

Monitoring the environment for visual events while performing a concurrent task requires adjustment of visual processing priorities. By use of Bundesen's (1990) Theory of Visual Attention (TVA), we investigated how monitoring for an object-based brief event affected distinct components of visual attention in a concurrent task. The perceptual salience of the event was varied. Monitoring reduced the processing speed in the concurrent task, and the reduction was stronger when the event was less salient. The monitoring task (...) neither affected the temporal threshold of conscious perception nor the storage capacity of visual short-term memory nor the efficiency of top-down controlled attentional selection. (shrink)

Attention is often conceived as a gateway to consciousness . Although endogenous spatial attention may be independent of conscious perception , exogenous spatial orienting seems instead to be an important modulator of CP . Here, we investigate the role of auditory alerting in CP in normal observers. We used a behavioral task in which phasic alerting tones were presented either at unpredictable or at predictable time intervals prior to the occurrence of a near-threshold visual target. We find, for (...) the first time in neurologically intact observers, that phasic alertness increases CP, both objectively and subjectively. This result is consistent with evidence showing that phasic alerting can ameliorate the spatial bias exhibited by visual neglect patients . The alerting network may increase the activity of fronto-parietal networks involved in top-down amplification required to bring a stimulus into consciousness. (shrink)

_A prize-winning scholar offers a sweeping exploration of the role doors have played in history_ Exploring a chapter not yet probed in the cultural history of the West, _The Strait Gate_ demonstrates how doors, gates, and related technologies such as the key and the lock have shaped the way we perceive and navigate the domestic and urban spaces that surround us in our everyday lives. Jütte reveals how doors have served as sites of power, exclusion, and inclusion—and, by extension, as (...) metaphors for salvation—in the course of Western history. This book makes it clear that doors, more than any other parts of the house, are the objects onto which we project our ideas of and anxieties about security, privacy, and shelter. Without doors, of course, houses could not exist. But even though we each walk through doorways well over a hundred times a day, we typically pay little attention to the doors we encounter. We regard them simply as a means of entering or leaving a building or room. Yet when our doors stop working as they should—when we find that we cannot lock or open them, for instance—we react with discomfort and anxiety. Drawing on a wide range of archival, literary, and visual sources, as well as on research literature across various disciplines and languages, Jütte pays particular attention to the history of the practices that have developed over the centuries in order to handle and control doors in everyday life. (shrink)