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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The following should be noted: The basal ganglia are involved in a wide range of self-initiated or remembered movements, action selection related to reward or punishment, preparation for movement as well as its execution and sequencing, and control of some movement parameters, such as amplitude and velocity. However, it appears that the planning and execution functions are mediated by separate neuronal populations in the basal ganglia.The basal ganglia are also involved in oculomotor activity as well, specifically in the control of saccadic eye movements, which are very rapid eye movements of velocity up to about 1000/s, that underlie visual fixation and rapid eye movements. The pathway involved is from the caudate nucleus to the SNr to the superior colliculus (not shown in Figure 12.6), where motoneurons controlling eye saccades are located.The same regions of the putamen receive projections from both the cortical somatomotor areas concerned with a given movement as well as the cortical somatosensory areas involved in the movement. The putamen can thus integrate both the motor and sensory aspects of a given movement.
Smart Eye-Tracking Sensors Based on Pixel-Level Image Processing Circuits
Published in Khosla Ajit, Kim Dongsoo, Iniewski Krzysztof, Optical Imaging Devices, 2017
Saccades are the rapid eye movements when we look around to examine our environment. Saccadic eye movements can vary considerably in magnitude, from less than 1° to more 100° as the situation demands. The peak velocity during the movement depends on the size of the saccade. For large saccades, it can reach 800°/s; because the velocity is so high, the movements are brief. The most frequently occurring saccades, which are smaller than 15°, take less than 50 ms from start to finish. Saccades are voluntary eye movements in the sense that we can consciously choose to look at, or ignore, things in the visual scene. Once initiated, however, the execution of the movement is automatic. During the eye movement, when the retinal image is sweeping rapidly across the retina, vision is actively suppressed.
Smart Eye Tracking Sensors Based on Pixel-Level Image Processing Circuits
Published in Iniewski Krzysztof, Integrated Microsystems, 2017
Saccades are the rapid eye movements occurring when we look around to examine our environment. Saccadic eye movements can vary considerably in magnitude, from less than 1° to more than 100° as the situation demands. The peak velocity during the movement depends on the size of the saccade. For large saccades it can reach 800°/s. because the velocity is so high, the movements are brief. The most frequently occurring saccades, which are smaller than 15°, take less than 50 ms from start to finish. Saccades are voluntary eye movements in the sense that we can consciously choose to look, or ignore, things in the visual scene. Once initiated, however, the execution of the movement is automatic. During the eye movement, when the retinal image is sweeping rapidly across the retina, vision is actively suppressed.
Eye Tracking, Usability, and User Experience: A Systematic Review
Published in International Journal of Human–Computer Interaction, 2023
Jakub Štěpán Novák, Jan Masner, Petr Benda, Pavel Šimek, Vojtěch Merunka
Regarding quantitative data usable for UX evaluation, the most used eye movement types are fixations and saccades, along with the remaining four base eye movement types like a smooth pursuit, optokinetic reflex, vestibular, and vergence (Jhani Adré de Bruin & Eloff, 2014). Fixation is the steady gaze of the eye on a specific point in space that allows for a clear and detailed perception of objects in the visual field and the accumulation of visual information over time (Rayner, 1978). On the other hand, saccades are rapid, jerky eye movements that occur during visual exploration and when shifting gaze from one point to another (Hafed, 2011). Saccades are essential for allowing the visual system to gather information about the environment and for allowing the eye to rapidly scan the visual field and focus on important or relevant stimuli (Findlay & Walker, 1999). Both fixation and saccades play critical roles in visual perception and eye-movement control, and a better understanding of these processes is important for a wide range of applications (Rayner et al., 2009).
Prediction of Dyslexia from Eye Movements Using Machine Learning
Published in IETE Journal of Research, 2022
The raw eye tracking data were analyzed and a broad set of unbiased and systematic features were extracted such that the total eye signal is preserved. Different types of events such as fixation duration, saccades both progressive and regressive were derived from the raw data by using statistical measures. Four different states are detected such as fixation, saccades, transient, and distortions. A fixation state is when the user gazes continuously at a point for a minimum of 50 milliseconds. Saccade state is when the eyes move rapidly while reading the text. Both progressive and regressive saccades have been observed. Transient state is when both horizontal and vertical positions of the eye are below 0.5 degrees. Distortion state is when both horizontal and vertical signals are dropped (i.e.) when the subject blinks A set of features for both fixation and saccades are defined. The following parameters are measured. (1) Duration of fixation and saccade. (2) Average position of the eye during the experiment. (3) Standard Deviation of average eye position. (4) Distance between two positions of the eye. (5) The average of both eye positions is measured. The above parameters have to be measured both horizontally and vertically. The mean and standard deviation for each parameter were computed, which gave a total of 75 features. These features captured all quantitative properties of the eye movement signal.
Effects of mobile news interface design features on users’ gaze behaviours and behavioural performance: evidence from China
Published in Behaviour & Information Technology, 2021
Xue-shuang Wang, Fu Guo, Ming-ming Li, Xiao-hui Tian
Eye movements are considered as a reliable indicator of attention (Poole and Ball 2006). It helps uncover subtle cognitive processing stages that are difficult to observe in visualisation evaluation studies (Vila and Gomez 2016). In human vision, eye movements are essential to cognitive processes as they carry visual attention to the specific parts of stimuli that are processed by the brain (Sharafi, Soh, and Guéhéneuc 2015). Visual attention is an ocular behaviour that was defined as a selective focus of central eyesight and follows a scan-path over the stimulus. A person’s gaze behaviour can be described in terms of two main elements: fixations and saccades (Cornish et al. 2019). Fixation refers to the eye movements that stabilise the retina over a stationary object of interest. It can imply the process of information acquisition (Luan et al. 2016), and tracking fixation is one of the most efficient ways to capture individual information from the external environment (Chae and Lee 2013). Fixation duration is believed to reflect the time required to process the information related to the fixation point (Rayner 1978). Generally, fixation count and fixation duration are the most commonly used metrics to measure users’ cognitive processing and visual attention (Just and Carpenter 1976; Luan et al. 2016). A saccade is a rapid eye movement from one fixation to another. The number of saccades in a scan path indicates the amount of visual search on a display, with more saccades representing a greater amount of search (Goldberg and Kotval 1999).