- 1. The point at which a stimulus first produces a sensation. 2. The lower limit of perception of a stimulus. 3. The minimal stimulus that produces excitation of any structure; e.g., the minimal stimulus eliciting a motor response. SYN: limen (2) [TA]. [A.S. therxold]- brightness difference t. the smallest difference that can be perceived as a difference in brightness. SYN: light difference (2).- convulsant t. the smallest amount of stimulation, electric current, or drug required to induce a convulsion.- differential t. the lowest limit at which two stimuli can be differentiated. SYN: t. differential.- double-point t. the least degree of separation of two points applied to the body surface that permits their being felt as two.- erythema t. the dose at which erythema of the skin is produced by irradiation with ultraviolet, gamma, or x-rays.- t. of nose SYN: limen nasi.- phenotypic t. a quantitative genetic trait with a continuous distribution termed its liability; may generate two kinds of phenotype, according to whether the liability lies above or below some critical t. at about which a radical change in behavior occurs. For instance, blood uric acid level is a liability with an approximately gaussian distribution. At a critical point of chemical saturation (the t.), crystallization occurs and the resulting gout or nongout is a t. trait.- relational t. the smallest degree of difference between two stimuli that permits them to be perceived as different.- speech awareness t. the lowest sound intensity at which speech can be detected. SYN: speech detection t..- speech reception t. the intensity at which speech is recognized as meaningful symbols; in speech audiometry, it is the decibel level at which 50% of spondee words can be repeated correctly by the subject.- swallowing t. 1. the moment that the act of swallowing begins after the mastication of food; 2. the critical moment of reflex action initiated by minimum stimulation, prior to the act of deglutition.- visual t., t. of visual sensation the minimal light intensity evoking a visual sensation. SYN: achromatic t., minimum light t..
* * *thresh·old 'thresh-.(h)ōld n the point at which a physiological or psychological effect begins to be produced (as the degree of stimulation of a nerve which just produces a response or the concentration of sugar in the blood at which sugar just begins to pass the barrier of the kidneys and enter the urine) <below the \threshold of consciousness> <the \threshold of pain> <a high renal clearance \threshold> called also limen
* * *n.(in neurology) the point at which a stimulus begins to evoke a response, and therefore a measure of the sensitivity of a system under particular conditions. A thermoreceptor that responds to an increase in temperature of only two degrees is said to have a much lower threshold than one that will only respond to a change in temperature of ten degrees or more. In this example the threshold can be measured directly in terms of degrees.
* * *thresh·old (threshґōld) 1. the minimum level of input required to cause some event to occur. 2. limen; that value at which a stimulus just produces a sensation, is just appreciable, or comes just within the limits of perception; see also absolute t. and differential t. 3. renal t. 4. in anatomy, limen (def. 2).
Medical dictionary. 2011.
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Threshold — may refer to:Books and comics* Threshold (novel), a 1985 science fiction novel by David R. Palmer * Threshold (Sara Douglass novel), a 1997 fantasy novel by Sara Douglass * Threshold , a 2001 science fiction novel by Caitlín R. KiernanFilm and… … Wikipedia
threshold — thresh‧old [ˈθreʆhəʊld, ʆəʊld ǁ oʊld] noun [countable] the level at which something belongs in a particular class or is affected by a particular rule: • Many large mortgages were taken out, on the assumption that interest rates would remain below … Financial and business terms
threshold — thresh·old 1 / thresh ˌhōld/ n: a point of beginning: a minimum requirement for further action; specif: a determination (as of fact or the existence of a reasonable doubt) upon which something else (as further consideration or a right of action)… … Law dictionary
Threshold — (engl. für „Schwelle“) bezeichnet einen Begriff aus der Teilchenphysik, siehe Schwellenergie einen Arbeitspunkt in MOS Transistoren (dt. Schwellspannung), siehe Metall Oxid Halbleiter Feldeffekttransistor einen Optimierungsalgorithmus, siehe… … Deutsch Wikipedia
threshold — [thresh′ōld΄, thresh′hōld΄] n. [ME threschwold < OE therscwold (akin to ON threskǫlder) < base of therscan (see THRASH) + ?] 1. DOORSILL 2. the entrance or beginning point of something [at the threshold of a new career] 3. Physiol. Psychol … English World dictionary
Threshold — Thresh old, n. [OE. threswold, [thorn]reshwold, AS. [thorn]rescwald, [thorn]erscwald, [thorn]erscold, [thorn]rescold, fr. [thorn]rescan, [thorn]erscan, to thresh; akin to Icel. [thorn]reskj[ o]de, [thorn]r[ o]skuldr, Sw. tr[ o]skel, Dan.… … The Collaborative International Dictionary of English
threshold — O.E. þrescold, þærscwold, þerxold doorsill, point of entering, first element related to O.E. þrescan (see THRESH (Cf. thresh)), with its original sense of tread, trample. Second element of unknown origin and much transformed in all the Germanic… … Etymology dictionary
threshold — threshold. См. порог. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
Threshold — [englisch, θreʃəʊld; wörtlich »Schwelle«], an bestimmten Effektgeräten (Flanger, Limiter, Noisegate u. a.) einstellbarer Pegel (Schwellwert), bei dessen Erreichen der beabsichtigte Effekt ausgelöst wird … Universal-Lexikon
threshold — Threshold Пороговый сигнал Наименьший сигнал на входе приемного устройства, при котором обеспечивается его регистрация с заданной достоверностью … Толковый англо-русский словарь по нанотехнологии. - М.
threshold — is spelt with one h (contrast withhold), and the h is optionally silent or aspirated in speech … Modern English usage