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In this issue of Neuron, Jordan and Keller (2020) explore subthreshold computations underlying predictive coding using whole-cell recordings in mouse visual cortex. Their findings suggest that layer 2/3, but not layer 5/6, neurons compute prediction errors by subtracting predicted and actual visual flow inputs generated by locomotion.

Sensory experience is often dependent on one’s own actions, including self-motion. Theories of predictive coding postulate that actions are regulated by calculating prediction error, which is the difference between sensory experience and expectation based on self-generated actions. Signals consistent with prediction error have been reported in mouse visual cortex (V1) when visual flow coupled to running is unexpectedly perturbed. Here, we show that such signals can be elicited by visual stimuli uncoupled with the animal’s running. We recorded the activity of mouse V1 neurons while presenting drifting gratings that unexpectedly stopped. We found strong responses to visual perturbations, which were enhanced during running. If these perturbation responses are signals about sensorimotor mismatch, they should be largest for front-to-back visual flow expected from the animals’ running. Responses, however, did not show a bias for front-to-back visual flow. Instead, perturbation responses were strongest in the preferred orientation of individual neurons and perturbation responsive neurons were more likely to prefer slow visual speeds. Our results therefore indicate that prediction error signals can be explained by the convergence of known motor and sensory signals in visual cortex, providing a purely sensory and motor explanation for purported mismatch signals.

Interface modules are defined by the concept of modularity according to the characteristics of mobile App interface. A modular design model containing five steps (namely: refine, prioritize, assemble, change, and select) is constructed. The proposed model feasibility is verified by its application to streamline the design of the mobile App interface with the multi-directional user experience features.

Summary Sensory experience often depends on one’s own actions, including self-motion. Theories of predictive coding postulate that actions are regulated by calculating prediction error, which is the difference between sensory experience and expectation based on self-generated actions. Signals consistent with prediction error have been reported in the mouse visual cortex (V1) when visual flow coupled to running was unexpectedly stopped. Here, we show that such signals can be elicited by visual stimuli uncoupled to an animal running. We record V1 neurons while presenting drifting gratings that unexpectedly stop. We find strong responses to visual perturbations, which are enhanced during running. Perturbation responses are strongest in the preferred orientation of individual neurons, and perturbation-responsive neurons are more likely to prefer slow visual speeds. Our results indicate that prediction error signals can be explained by the convergence of known motor and sensory signals, providing a purely sensory and motor explanation for purported mismatch signals., Graphical abstract, Highlights • Mouse primary visual cortex neurons respond to perturbations of visual flow • Perturbation responses are enhanced by running • Perturbation responses are stronger in the preferred orientation of the neurons • Perturbation-responsive neurons are tuned to slow visual speeds, Muzzu and Saleem find neurons in the mouse visual cortex responding to stops or perturbations of open-loop visual flow. Perturbation responses are enhanced by running, and responsive neurons prefer low visual speeds. These results suggest concurrent selectivity for low visual speeds and running can explain sensorimotor mismatch signals in the visual cortex.

All Smartphones have become a necessity rather than a utility. Not a single person can deny that our mobile phones go wherever we go. Phones were created as a means for more accessible communication over distance. The purpose of a phone has dramatically changed over the years by the technology advancement and the arrival of smartphones which provides many applications and make us stick to it. This study understands the correlation between the activity of eyes and flow level of the eye. Also, how the visual activity parameters are calculated will be discussed. This study enhances the understanding of visual fatigue caused due to the digital medium. Examine the subject’s eye flow level with smartphone and VDT utilisation. Besides, the application of learning algorithms, including machine learning/deep learning is massive with regards to analysing visual fatigue. The purpose of this study also going to discuss the application of both machine learning and deep learning on analysing visual fatigue caused by Digital Medium.

Grids, matrices, and tables are commonly used to organize information. A number of design techniques and psychological principles address how viewers’ eyes can be guided through a visual work. Designers refer to such objectives as "creating visual flow." One common technique, “zebra-shading,” is intended to guide eyes through the grid by alternating shaded and unshaded rows or columns. However, the effects of these manipulations have largely not been explored experimentally. We will review the techniques designers use to guide the eyes of their audience, associated psychological foundations, and outline some research done on the graphic design of a specific type of grid: tables. Then, we will describe an experiment wherein participants conducted a visual search task in grids with different shading manipulations. The analysis showed data trending toward improved response time when the target followed the shading.

The purpose of this study was to evaluate the effects of a visual flow speed‘s modulation-based VR(virtual reality) program on gait function in stroke patients. Thirty one stroke patients were randomly selected at Dep. of Rehabilitation medicine of M hospital in Seoul. We carried out the gait analysis by dividing them with four conditions : one condition had applied without the visual flow modulation-based VR and another had done three visual flow speed's modulation-based VR(0.25, 1, 2 times). The gait analysis was used with GaitRite system. The data were collected using gait velocity, cadence, stride length, step length, single support time, and double support time during treatment. The results were as follows. First, the slow visual flow(0.25 times)-based VR program on the condition was significant decrease gait velocity, cadence, stride length, step length and increase single support time, double support time(p

We introduce a novel tool for visualizing netflow traffic on enterprise networks called 3D Parallel Coordinate Planes (3DPCP). This tool provides operators with the ability to manipulate the visual flow of network traffic information by arranging two-dimensional planes along a vertical time axis in 3D space.

Scientific visualization is widely used for the analysis of datasets obtained from measurements and numerical simulations. However, scientists and engineers are not always visualization experts who are familiar with how to map their numerical data to proper graphical primitives to yield optimal visualization. Therefore, we have built on modular visualization environments (MVEs) to develop a design support system, called GADGET, for scientific visualization applications. In this paper, we attempt to reexamine specifications for design directives to make the GADGET system tailored to visual flow data mining.

Humans have a limitation in the information flow that can process. This article sumarizes the main biological sources of this limitation and make some reflexions over the impact on the interaction with computers in order to prevent an ergonomic design.

Whenever we move, we gain experience with how changes in visual flow are related to movement through the environment. One way that researchers have studied these perception-action linkages is through perturbing the normal relationship between perception and action [Kunz et al. 2009; Rieser et al. 1995]. In these studies, people experience an optic flow rate that is manipulated to be significantly faster or slower than their walking rate. Comparison of distance estimates from before and after this recalibration experience typically shows that people who experience faster optic flow undershoot targets at posttest and people who experience slower optic flow overshoot targets at posttest. Here, we examined how experience with mismatched perception and action (i.e., faster or slower optic flow) in a virtual environment affects subsequent distance estimation in the same virtual environment and in a similar real environment. Of particular interest was whether perception-action coupling is more malleable in the virtual environment than in the real environment.

To control upright stance, the human nervous system must estimate the movements of multiple body segments based on multisensory information. To investigate how visual information contributes to such multisegmental estimation, participants were exposed to 3 types of visual-scene movement: translation in the anteroposterior direction, rotation about the ankle joint, and rotation about the hip joint. Trunk and leg responses were larger for rotational than for translational movements, but only at lower stimulus frequencies. Based on a feedback-control theoretical framework, these results indicated that visual inputs distinguish between translation and rotation of the head. Also, visual condition effects were similar for the leg and trunk segments, suggesting a control strategy with a single control signal that determines the activation of all muscles.

After a review of the purpose and biological background of Head Direction Cells, and existing models of them, we introduce an improved neural model that integrates visual flow information with the vestibular inputs found in earlier models. Simulation results using real video inputs are presented to explore and validate the new model, the evolutionary advantages for the proposed arrangement are noted, its utility for use in robot controllers is discussed, and suggestions are made for further work in this area.

It is typically assumed that basic features of human gait are determined by purely biomechanical factors. In two experiments, we test whether gait transition speed and preferred walking speed are also influenced by visual information about the speed of self-motion. The visual flow during treadmill locomotion was manipulated to be slower than, matched to, or faster than the physical gait speed (visual gains of 0.5, 1.0, 2.0). Higher flow rates elicit significantly lower transition speeds for both the Walk-Run and Run-Walk transition, as expected. Similarly, higher flow rates elicit significantly lower preferred walking speeds. These results suggest that visual information becomes calibrated to mechanical or energetic aspects of gait and contributes to the control of locomotor behavior.

Traversed distance perception involves estimating the extent of self-motion as one travels from one position in space to another. As such, it is a multi-modal experience in which information from both visual flow and locomotor cues (i.e. proprioceptive, efference copy and vestibular cues) jointly specify the magnitude of self-motion. While recent evidence has demonstrated the extent to which each of these cues can be used independently to estimate traversed distance, relatively little is known about how they are integrated when simultaneously present. Evaluating multi-modal cue integration in the context of dynamic locomotor behaviour is important to both understanding issues related to self-motion perception, as well as perceptual-motor coupling in real and virtual environments.

To reveal the underlying cellular mechanisms of the noise tolerance in the discrimination of the direction of visual flow, we analyzed both response behaviors of directionally selective cells in the d-MST of the macaque and discrimination properties of human subjects for visual flow by using large-field texture flow. The stimulus was a 32/spl times/32-pixel random checker pattern refreshed at every 16 msec in which coherency of the motion of the texture was systematically controlled by a special purpose computer. The discrimination performance of the human observers showed a high degree of tolerance for directional noise. Field-type D-cells in d-MST also showed response properties which closely resembled human discrimination performance. These results strongly suggest that cells in d-MST area play a crucial role in the generation of signals for perception of global motion.

At a glance Figures View all figures Figure 1: Arrows in scientific diagrams. (a) Well-understood conventions in molecular biology indicated by arrows. (b) Arrows are defined loosely by their geometric shapes and more definitely in context. (c) A diagram with 19 arrows used as leaders, to indicate reagent flow and to show mechanical movement. Reprinted from Nature Methods3. Full size image View in article Figure 2: Functional qualities of arrows. (a) The use of arrows versus lines as connectors suggests a certain functional relationship. (b) Alternatives to arrows as leader lines. (c) Reasonably sized arrows clearly indicate direction without being a distraction. (d) Trapped whitespace in 'open' arrowheads creates optical illusions that can attract unwanted attention. (e) Whitespace at the ends of the arrows makes them easy to discriminate from other content. (f) Orienting arrows in similar directions creates natural visual flow. Full size image View in article

Grasping behavior starts from a set of biologically-determined tonic and postural adaptations that constitute the fulcrum of the movement. The analysis of these starting points and their transformation through the first months of life allows to better situate grasping behavior.

A computational model for visual flow-field cueing and self-motion estimation is developed and simulated. The model is predicated on the notion that the pilot makes noisy, sampled measurements on the spatially distributed visual flow-field surrounding him and, on the basis of these measurements, generates estimates of his own linear and angular terrain-relative velocities which optimally satisfy, in a least-squares sense, the visual kinematic flow constraints. The least-squares formulation is applicable to general observer motions and viewing geometries; it is projection-plane independent and rational in its treatment of redundant and noisy flow cues. A subsidiary but significant output of the model is an `impact time' map, and observer-centered spatially scaled replica of the viewed surface. Simulations are presented to demonstrate the parametric sensitivity and ability to model relevant human visual performance data. Preliminary simulation results of human visual performance are encouraging.

The paper is an experimental investigation of the aerated-thermosyphon, or aerosyphon. The work combines a visual flow study with a series of heat-transfer experiments in an attempt to understand the modus operandi of the device and explore its unusual heat-transfer characteristics.

Contrary to a previous assumption, the center of the expanding pattern of visual flow is not generally useful as an aid in judging the direction of self motion since its direction depends on the direction of gaze. For some visual environments, however, the point of maximum rate of change of magnification in the retinal image coincides with the direction of self motion, independently of the direction of gaze. This visual indicator could be used to judge the direction of self motion.

The paper presents experimental evidence for homing by path integration in a bird. Using a mammalian model case, the essentials of a cybernetical theory of this type of navigation are developed. As a consequence of its application to the extant data on geese, the necessary information about the translatory component of the animal’s movement along its path appears to be provided by the visual system, viz. the translatory component of the visual flow, whereas the rotatory information must (also) have non-visual sources, e.g. the semicircular canals or the magnetic field.

Self-motion induces spontaneous eye movements which serve the purpose of stabilizing the visual image on the retina. Previous studies have mainly focused on their reflexive nature and how the perceptual system disentangles visual flow components caused by eye movements and self-motion. Here, we investigated the role of eye movements in distance reproduction (path integration). We used bimodal (visual-auditory)-simulated self-motion: visual optic flow was paired with an auditory stimulus whose frequency was scaled with simulated speed. The task of the subjects in each trial was, first, to observe the simulated self-motion over a certain distance (Encoding phase) and, second, to actively reproduce the observed distance using only visual, only auditory, or bimodal feedback (Reproduction phase). We found that eye positions and eye speeds were strongly correlated between the Encoding and the Reproduction phases. This was the case even when reproduction relied solely on auditory information and thus no visual stimulus was presented. We believe that these correlations are indicative of a contribution of eye movements to path integration.