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Riddoch Syndrome
The Riddoch syndrome is a term coined by Zeki and Ffytche (1998) in a paper published in '' Brain''. The term acknowledges the work of George Riddoch who was the first to describe a condition in which a form of visual impairment, caused by lesions in the occipital lobe, leaves the sufferer blind but able to distinguish visual stimuli with specific characteristics when these appear in the patient's blind field. The most common stimuli that can be perceived ''consciously'' are the presence and direction of fast moving objects (moving at a speed in excess of 10 degrees per second); in his work these moving objects were described as "vague and shadowy". Riddoch concluded from his observations that "movement may be recognized as a special visual perception". Riddoch's description was dismissed by Sir Gordon Holmes in a 1918 paper in which he wrote that "The condition described by Riddoch should not be spoken of as a dissociation of the elements of visual sensation" because "occipital ...
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Brain (journal)
''Brain: A Journal of Neurology'' is a peer-reviewed scientific journal of neurology, founded in 1878 by John Charles Bucknill, David Ferrier, James Crichton-Browne and John Hughlings Jackson. It is published by Oxford University Press. The journal was edited by John Newsom-Davis from 1997 to 2004, Alastair Compston (Cambridge University) until 2013, and Dimitri Kullmann (UCL) until 2021. The current editor-in-chief is Masud Husain (University of Oxford). According to the '' Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 15.255. References External links * Publications established in 1878 Oxford University Press academic journals Neurology journals Neuroscience journals Monthly journals English-l ...
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Visual Impairment
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment– visual impairment may cause the individual difficulties with normal daily tasks including reading and walking. Low vision is a functional definition of visual impairment that is chronic, uncorrectable with treatment or correctable lenses, and impacts daily living. As such low vision can be used as a disability metric and varies based on an individual's experience, environmental demands, accommodations, and access to services. The American Academy of Ophthalmology defines visual impairment as the best-corrected visual acuity of less than 20/40 in the better eye, and the World Health Organization defines it as a presenting acuity of less than 6/12 in the better eye. The term blindness is used for complete or nearly complete vision loss. In ...
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Lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classification or naming convention for lesions. Since lesions can occur anywhere in the body and the definition of a lesion is so broad, the varieties of lesions are virtually endless. Generally, lesions may be classified by their patterns, their sizes, their locations, or their causes. They can also be named after the person who discovered them. For example, Ghon lesions, which are found in the lungs of those with tuberculosis, are named after the lesion's discoverer, Anton Ghon. The characteristic skin lesions of a varicella zoster virus infection are called '' chickenpox''. Lesions of the teeth are usually called dental caries. Location Lesions are often classified by their tissue types or locations. For example, a "skin lesion" or a " ...
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Occipital Lobe
The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head". The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1 (visual one). Human V1 is located on the medial side of the occipital lobe within the calcarine sulcus; the full extent of V1 often continues onto the occipital pole. V1 is often also called striate cortex because it can be identified by a large stripe of myelin, the Stria of Gennari. Visually driven regions outside V1 are called extrastriate cortex. There are many extrastriate regions, and these are specialized for different visual tasks, such as visuospatial processing, color differentiation, and motion perception. Bilateral lesions of the occipital lobe can l ...
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Blindsight
Blindsight is the ability of people who are cortically blind to respond to visual stimuli that they do not consciously see due to lesions in the primary visual cortex, also known as the striate cortex or Brodmann Area 17. The term was coined by Lawrence Weiskrantz and his colleagues in a paper published in a 1974 issue of ''Brain''. A previous paper studying the discriminatory capacity of a cortically blind patient was published in ''Nature'' in 1973. Type classification The majority of studies on blindsight are conducted on patients who are hemianopic, i.e. blind in one half of their visual field. Following the destruction of the left or right striate cortex, patients are asked to detect, localize, and discriminate amongst visual stimuli that are presented to their blind side, often in a forced-response or guessing situation, even though they may not consciously recognize the visual stimulus. Research shows that such blind patients may achieve a higher accuracy than would be ex ...
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Scotoma
A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mammalian eye has a scotoma in its field of vision, usually termed its blind spot. This is a location with no photoreceptor cells, where the retinal ganglion cell axons that compose the optic nerve exit the retina. This location is called the optic disc. There is no direct conscious awareness of visual scotomas. They are simply regions of reduced information within the visual field. Rather than recognizing an incomplete image, patients with scotomas report that things "disappear" on them. The presence of the blind spot scotoma can be demonstrated subjectively by covering one eye, carefully holding fixation with the open eye, and placing an object (such as one's thumb) in the lateral and horizontal visual field, about 15 degrees from fix ...
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Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts ...
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All Things Considered
''All Things Considered'' (''ATC'') is the flagship news program on the American network National Public Radio (NPR). It was the first news program on NPR, premiering on May 3, 1971. It is broadcast live on NPR affiliated stations in the United States, and worldwide through several different outlets, formerly including the NPR Berlin station in Germany. ''All Things Considered'' and '' Morning Edition'' were the highest rated public radio programs in the United States in 2002 and 2005. The show combines news, analysis, commentary, interviews, and special features, and its segments vary in length and style. ''ATC'' airs weekdays from 4:00 p.m. to 6:00 p.m. Eastern Time (live) or Pacific Time (recorded with some updates; in Hawaii it airs as a fully recorded program) or from 3:00 p.m. to 5:00 p.m. Central Time. A weekend version of ''ATC'', ''Weekend All Things Considered'', airs on Saturdays and Sundays. Background ''ATC'' programming combines news, analysis, ...
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WAMU
WAMU (88.5 FM) is a public news/ talk station that services the greater Washington, D.C. metropolitan area. It is owned by American University, and its studios are located near the campus in northwest Washington. WAMU has been the primary National Public Radio member station for Washington since 2007. History WAMU began as an AM carrier-current student radio station, signing on July 28, 1951 on , before shifting to in March 1952 and in November 1952. Although carrier-current stations are not granted a license or call sign by the FCC, it used "WAMU" as a familiar form of identification. The station aired a wide range of student-produced programming including music, news, sports, radio dramas, and debates. The station was heralded as a rebirth of the university's prior radio station, WAMC, which operated on for about two years starting on January 15, 1947, broadcasting with a 50-watt transmitter as part of a plan to offer a full range of radio and television courses at Americ ...
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Ophthalmology
Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medical degree, a doctor specialising in ophthalmology must pursue additional postgraduate residency training specific to that field. This may include a one-year integrated internship that involves more general medical training in other fields such as internal medicine or general surgery. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care - medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training and many include research as ...
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Blindness
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment– visual impairment may cause the individual difficulties with normal daily tasks including reading and walking. Low vision is a functional definition of visual impairment that is chronic, uncorrectable with treatment or correctable lenses, and impacts daily living. As such low vision can be used as a disability metric and varies based on an individual's experience, environmental demands, accommodations, and access to services. The American Academy of Ophthalmology defines visual impairment as the best-corrected visual acuity of less than 20/40 in the better eye, and the World Health Organization defines it as a presenting acuity of less than 6/12 in the better eye. The term blindness is used for complete or nearly complete vision loss. In ...
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