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Pursuit System
In the scientific study of vision, smooth pursuit describes a type of eye movement in which the eyes remain fixated on a moving object. It is one of two ways that visual animals can voluntarily shift gaze, the other being saccadic eye movements. Pursuit differs from the vestibulo-ocular reflex, which only occurs during movements of the head and serves to stabilize gaze on a stationary object. Most people are unable to initiate pursuit without a moving visual signal. The pursuit of targets moving with velocities of greater than 30°/s tends to require catch-up saccades. Smooth pursuit is asymmetric: most humans and primates tend to be better at horizontal than vertical smooth pursuit, as defined by their ability to pursue smoothly without making ''catch-up saccades''. Most humans are also better at downward than upward pursuit. Pursuit is modified by ongoing visual feedback. Measurement There are two basic methods for recording smooth pursuit eye movements, and eye movement in ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attention
Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively. William James (1890) wrote that "Attention is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence." Attention has also been described as the allocation of limited cognitive processing resources. Attention is manifested by an attentional bottleneck, in terms of the amount of data the brain can process each second; for example, in human vision, less than 1% of the visual input data stream of 1MByte/sec can enter the bottleneck, leading to inattentional blindness. Attention remains a crucial area of investigation within education, psychology, neuroscience, cognitive neuroscience, and neuropsychology. Areas of activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endophenotype
In genetic epidemiology, endophenotype (or intermediate phenotype) is a term used to separate behavioral symptoms into more stable phenotypes with a clear genetic connection. By seeing the EP notion as a special case of a larger collection of multivariate genetic models, which may be fitted using currently accessible methodology, it is possible to maximize its valuable potential lessons for etiological study in psychiatric disorders. The concept was coined by Bernard John and Kenneth R. Lewis in a 1966 paper attempting to explain the geographic distribution of grasshoppers. They claimed that the particular geographic distribution could not be explained by the obvious and external " exophenotype" of the grasshoppers, but instead must be explained by their microscopic and internal "endophenotype". The endophenotype idea represents the influence of two important conceptual currents in biology and psychology research. An adequate technology would be required to perceive the endoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Colliculus
In neuroanatomy, the superior colliculus () is a structure lying on the tectum, roof of the mammalian midbrain. In non-mammalian vertebrates, the Homology (biology), homologous structure is known as the optic tectum or optic lobe. The adjective form ''tectum, tectal'' is commonly used for both structures. In mammals, the superior colliculus forms a major component of the midbrain. It is a paired structure and together with the paired inferior colliculi forms the corpora quadrigemina. The superior colliculus is a layered structure, with a pattern that is similar in all mammals. The layers can be grouped into the superficial layers (retinal nerve fiber layer, stratum opticum and above) and the deeper remaining layers. Neurons in the superficial layers receive direct input from the retina and respond almost exclusively to visual stimuli. Many neurons in the deeper layers also respond to other modalities, and some respond to stimuli in multiple modalities. The deeper layers also conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccade
In vision science, a saccade ( ; ; ) is a quick, simultaneous movement of both Eye movement (sensory), eyes between two or more phases of focal points in the same direction. In contrast, in Smooth pursuit, smooth-pursuit movements, the eyes move smoothly instead of in jumps. Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for focal points, rapid eye movement, and the fast phase of optokinetic reflex, optokinetic nystagmus. The word appears to have been coined in the 1880s by French ophthalmologist Louis Émile Javal, Émile Javal, who used a mirror on one side of a page to observe eye movement in silent reading, and found that it involves a succession of discontinuous individual movements. Function Humans and many organisms do not look at a scene in steadiness; instead, the eyes move around, locating interesting parts of the scene and building up a three-dimensional 'map' corresponding to the scen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsaccade
Microsaccades are a kind of fixational eye movement. They are small, jerk-like, involuntary eye movements, similar to miniature versions of voluntary saccades. They typically occur during prolonged visual fixation (of at least several seconds), not only in humans, but also in animals with foveal vision (primates, cats, dogs etc.). Microsaccade amplitudes vary from 2 to 120 arcminutes. The first empirical evidence for their existence was provided by Robert Darwin, the father of Charles Darwin. Function The role of microsaccades in visual perception has been a highly debated topic that is still largely unresolved. It has been proposed that microsaccades correct displacements in eye position produced by drifts, although non-corrective microsaccades also occur. Some work has suggested that microsaccades are directly correlated with the perception of illusory motion. Although microsaccades can enhance vision of fine spatial detail, they can also impair visual perception in that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frontal Eye Fields
The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, of the primate brain. In humans, it can be more accurately said to lie in a region around the intersection of the middle frontal gyrus with the precentral gyrus, consisting of a frontal and parietal portion. The FEF is responsible for Saccade, saccadic eye movements for the purpose of visual field perception and awareness, as well as for voluntary eye movement. The FEF communicates with extraocular muscles indirectly via the paramedian pontine reticular formation. Destruction of the FEF causes deviation of the eyes to the ipsilateral side. Function The cortical area called the frontal eye field (FEF) plays an important role in the control of visual attention and eye movements. Electrical stimulation in the FEF elicits saccadic eye movements. The FEF have a topographic structure and represents saccade targets in retinotopic coordinates. The frontal eye field is rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Tracking
Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head. An eye tracker is a device for measuring eye positions and eye movement. Eye trackers are used in research on the visual system, in psychology, in psycholinguistics, marketing, as an input device for human-computer interaction, and in product design. In addition, eye trackers are increasingly being used for assistive and rehabilitative applications such as controlling wheelchairs, robotic arms, and prostheses. Recently, eye tracking has been examined as a tool for the early detection of autism spectrum disorder. There are several methods for measuring eye movement, with the most popular variant using video images to extract eye position. Other methods use search coils or are based on the electrooculogram. History In the 1800s, studies of eye movement were made using direct observations. For example, Louis Émile Javal observed in 187 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Movement (sensory)
Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of interests. A special type of eye movement, rapid eye movement, occurs during REM sleep. The eyes are the visual organs of the human body, and move using a system of six muscles. The retina, a specialised type of tissue containing photoreceptors, senses light. These specialised cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as vision in the visual cortex. Primates and many other vertebrates use three types of voluntary eye movement to track objects of interest: smooth pursuit, vergence shifts and saccades. These types of movements appear to be initiated by a small cortical region in the brain's frontal lobe. This is corroborated by removal of the fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketamine
Ketamine is a cyclohexanone-derived general anesthetic and NMDA receptor antagonist with analgesic and hallucinogenic properties, used medically for anesthesia, depression, and pain management. Ketamine exists as its S- (esketamine) and R- (arketamine) two enantiomers and has antidepressant action likely involving additional mechanisms than NMDA antagonism. At anesthetic doses, ketamine induces a state of dissociative anesthesia, a trance-like state providing pain relief, sedation, and amnesia. Its distinguishing features as an anesthestic are preserved breathing and airway reflexes, stimulated heart function with increased blood pressure, and moderate bronchodilation. As an anesthetic, it is used especially in trauma, Emergency medical services, emergency, and Pediatrics, pediatric cases. At lower, sub-anesthetic doses, it is used as a treatment for pain and treatment-resistant depression. Ketamine is legally used in medicine but is also tightly controlled due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phencyclidine
Phencyclidine or phenylcyclohexyl piperidine (PCP), also known in its use as a street drug as angel dust among other names, is a dissociative anesthetic mainly used recreationally for its significant mind-altering effects. PCP may cause hallucinations, distorted perceptions of sounds, and psychotic behavior. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco. Adverse effects may include paranoia, addiction, and an increased risk of suicide, as well as seizures and coma in cases of overdose. Flashbacks may occur despite stopping usage. Chemically, PCP is a member of the arylcyclohexylamine class. PCP works primarily as an NMDA receptor antagonist. PCP is most commonly used in the US. While usage peaked in the US in the 1970s, between 2005 and 2011, an increase in visits to emergency departments as a result of the drug occurred. As of 2022, in the US, about 0.7% of 12th-grade ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Sobriety Tests
Field sobriety tests (FSTs), also referred to as standardized field sobriety tests (SFSTs), are a battery of tests used by police officers to determine if a person suspected of impaired driving is intoxicated with alcohol or other drugs. ''FSTs'' (and ''SFSTs'') are primarily used in the United States and Canada, to meet " probable cause for arrest" requirements (or the equivalent in either country), necessary to sustain an alcohol-impaired driving (DWI or DUI) conviction based on a chemical blood alcohol test. Background Impaired driving Impaired driving, referred to as Driving Under the Influence (DUI), or Driving While Intoxicated (DWI), is the crime of driving a motor vehicle while impaired by alcohol or other drugs (including recreational drugs and those prescribed by physicians), to a level that renders the driver incapable of operating a motor vehicle safely. People who receive multiple DUI offenses are often people struggling with alcoholism or alcohol dependence. Tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
