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Amnesiac
Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use of various sedatives and hypnotic drugs. The memory can be either wholly or partially lost due to the extent of damage that was caused. There are two main types of amnesia: retrograde amnesia and anterograde amnesia. Retrograde amnesia is the inability to retrieve information that was acquired before a particular date, usually the date of an accident or operation. In some cases the memory loss can extend back decades, while in others the person may lose only a few months of memory. Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store. People with anterograde amnesia cannot remember things for long periods of time. These two types are not mutually exclusive; both can occur simul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Memory
Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to short-term and working memory, which persist for only about 18 to 30 seconds. Long-term memory is commonly labelled as explicit memory ( declarative), as well as episodic memory, semantic memory, autobiographical memory, and implicit memory (procedural memory). Dual-store memory model According to Miller, whose paper in 1956 popularized the theory of the "magic number seven", short-term memory is limited to a certain number of chunks of information, while long-term memory has a limitless store. Atkinson–Shiffrin memory model According to the dual store memory model proposed by Richard C. Atkinson and Richard Shiffrin in 1968, memories can reside in the short-term "buffer" for a limited time while they are simultaneously strengthening their associations in long-term memory. When items are first presented, they enter sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterograde Amnesia
In neurology, anterograde amnesia is the inability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact. This is in contrast to retrograde amnesia, where memories created prior to the event are lost while new memories can still be created. Both can occur together in the same patient. To a large degree, anterograde amnesia remains a mysterious ailment because the precise mechanism of storing memories is not yet well understood, although it is known that the regions of the brain involved are certain sites in the temporal cortex, especially in the hippocampus and nearby subcortical regions. Signs and symptoms People with anterograde amnesic syndromes may present with widely varying degrees of forgetfulness. Some with severe cases have a combined form of anterograde and retrograde amnesia, sometimes called global amnesia. In the case of drug-i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychiatry
Psychiatry is the medical specialty devoted to the diagnosis, prevention, and treatment of mental disorders. These include various maladaptations related to mood, behaviour, cognition, and perceptions. See glossary of psychiatry. Initial psychiatric assessment of a person typically begins with a case history and mental status examination. Physical examinations and psychological tests may be conducted. On occasion, neuroimaging or other neurophysiological techniques are used. Mental disorders are often diagnosed in accordance with clinical concepts listed in diagnostic manuals such as the ''International Classification of Diseases'' (ICD), edited and used by the World Health Organization (WHO) and the widely used '' Diagnostic and Statistical Manual of Mental Disorders'' (DSM), published by the American Psychiatric Association (APA). The fifth edition of the DSM (DSM-5) was published in May 2013 which re-organized the larger categories of various diseases and expanded upon the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantic
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy, linguistics and computer science. History In English, the study of meaning in language has been known by many names that involve the Ancient Greek word (''sema'', "sign, mark, token"). In 1690, a Greek rendering of the term ''semiotics'', the interpretation of signs and symbols, finds an early allusion in John Locke's ''An Essay Concerning Human Understanding'': The third Branch may be called [''simeiotikí'', "semiotics"], or the Doctrine of Signs, the most usual whereof being words, it is aptly enough termed also , Logick. In 1831, the term is suggested for the third branch of division of knowledge akin to Locke; the "signs of our knowledge". In 1857, the term ''semasiology'' (borrowed from German ''Semasiologie'') is attested in Josiah W. Gibbs' '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissociative Amnesia
Psychogenic amnesia or dissociative amnesia is a memory disorder characterized by sudden retrograde episodic memory loss, said to occur for a period of time ranging from hours to years to decades. More recently, "dissociative amnesia" has been defined as a dissociative disorder "characterized by retrospectively reported memory gaps. These gaps involve an inability to recall personal information, usually of a traumatic or stressful nature." In a change from the DSM-IV to the DSM-5, dissociative fugue is now subsumed under dissociative amnesia. The atypical clinical syndrome of the memory disorder (as opposed to organic amnesia) is that a person with psychogenic amnesia is profoundly unable to remember personal information about themselves; there is a lack of conscious self-knowledge which affects even simple self-knowledge, such as who they are. Psychogenic amnesia is distinguished from organic amnesia in that it is supposed to result from a nonorganic cause: no structural brain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroconvulsive Therapy
Electroconvulsive therapy (ECT) is a psychiatry, psychiatric treatment where a generalized seizure (without muscular convulsions) is electrically induced to manage refractory mental disorders.Rudorfer, MV, Henry, ME, Sackeim, HA (2003)"Electroconvulsive therapy". In A Tasman, J Kay, JA Lieberman (eds) ''Psychiatry, Second Edition''. Chichester: John Wiley & Sons Ltd, 1865–1901. Typically, 70 to 120 volts are applied externally to the patient's head, resulting in approximately 800 amperes, milliamperes of direct current passing between the electrodes, for a duration of 100 milliseconds to 6 seconds, either from temple to temple (bilateral ECT) or from front to back of one side of the head (unilateral ECT). However, only about 1% of the electrical current crosses the bony skull into the brain because skull Electrical impedance, impedance is about 100 times higher than skin Electrical impedance, impedance. The ECT procedure was first conducted in 1938 by Italian psychiatrist Ugo C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of cells, and disuse or lack of exercise or disease intrinsic to the tissue itself. In medical practice, hormonal and nerve inputs that maintain an organ or body part are said to have ''trophic'' effects. A diminished muscular trophic condition is designated as ''atrophy''. Atrophy is reduction in size of cell, organ or tissue, after attaining its normal mature growth. In contrast, hypoplasia is the reduction in the cellular numbers of an organ, or tissue that has not attained normal maturity. Atrophy is the general physiological process of reabsorption and breakdown of tissues, involving apoptosis. When it occurs as a result of disease or loss of trophic support because of other diseases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head Trauma
A head injury is any injury that results in trauma to the skull or brain. The terms ''traumatic brain injury'' and ''head injury'' are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of injuries, there are many causes—including accidents, falls, physical assault, or traffic accidents—that can cause head injuries. The number of new cases is 1.7 million in the United States each year, with about 3% of these incidents leading to death. Adults have head injuries more frequently than any age group resulting from falls, motor vehicle crashes, colliding or being struck by an object, or assaults. Children, however, may experience head injuries from accidental falls or intentional causes (such as being struck or shaken) leading to hospitalization. Acquired brain injury (ABI) is a term used to differentiate brain injuries occurring after birth from injury, from a genetic disorder, or from a congenital disorder. Unlike a broken bon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korsakoff's Syndrome
Korsakoff syndrome (KS) is a disorder of the central nervous system characterized by amnesia, deficits in explicit memory, and confabulation. This neurological disorder is caused by a deficiency of thiamine (vitamin B1) in the brain, and it is typically associated with and exacerbated by the prolonged, excessive ingestion of alcohol. Korsakoff syndrome is often accompanied by Wernicke encephalopathy; this combination is called Wernicke–Korsakoff syndrome. Korsakoff syndrome is named after Sergei Korsakoff, the Russian neuropsychiatrist who described it during the late 19th century. Signs and symptoms There are seven major symptoms of Korsakoff syndrome, an amnestic- confabulatory syndrome: # anterograde amnesia, memory loss for events after the onset of the syndrome # retrograde amnesia, memory loss extends back for some time before the onset of the syndrome # amnesia of fixation, also known as fixation amnesia (loss of immediate memory, a person being unable to remember eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premotor Cortex
The premotor cortex is an area of the motor cortex lying within the frontal lobe of the brain just anterior to the primary motor cortex. It occupies part of Brodmann's area 6. It has been studied mainly in primates, including monkeys and humans. The functions of the premotor cortex are diverse and not fully understood. It projects directly to the spinal cord and therefore may play a role in the direct control of behavior, with a relative emphasis on the trunk muscles of the body. It may also play a role in planning movement, in the spatial guidance of movement, in the sensory guidance of movement, in understanding the actions of others, and in using abstract rules to perform specific tasks. Different subregions of the premotor cortex have different properties and presumably emphasize different functions. Nerve signals generated in the premotor cortex cause much more complex patterns of movement than the discrete patterns generated in the primary motor cortex. Structure The premo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an external and internal region, and in the division of the striatum. The basal ganglia are situated at the base of the forebrain and top of the midbrain. Basal ganglia are strongly interconnected with the cerebral cortex, thalamus, and brainstem, as well as several other brain areas. The basal ganglia are associated with a variety of functions, including control of voluntary motor movements, procedural learning, habit learning, conditional learning, eye movements, cognition, and emotion. The main components of the basal ganglia – as defined functionally – are the striatum, consisting of both the dorsal striatum (caudate nucleus and putamen) and the ventral striatum (nucleus accumbens and olfactory tubercle), the globus pallidus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FMRI
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa in 1990. This is a type of specialized brain and body scan used to map neural activity in the brain or spinal cord of humans or other animals by imaging the change in blood flow (hemodynamic response) related to energy use by brain cells. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not involve the use of injections, surgery, the ingestion of substances, or exposure to ionizing radiation. This measure is frequently corrupted by noise from various sources; hence, statistical procedures are used to extract the underlying signal. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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