| illusion | 1. <psychology> An unreal image presented to the bodily or mental vision; a deceptive appearance; a false show; mockery; hallucination. "To cheat the eye with blear illusions." (Milton) 2. Hence: Anything agreeably fascinating and charning; enchantment; witchery; glamour. "Ye soft illusions, dear deceits, arise!" (Pope) 3. <physiology> A sensation originated by some external object, but so modified as in any way to lead to an erroneous perception; as when the rolling of a wagon is mistaken for thunder. Some modern writers distinguish between an illusion and hallucination, regarding the former as originating with some external object, and the latter as having no objective occasion whatever. Illusion refers particularly to errors of the sense, delusion to false hopes or deceptions of the mind. An optical deception is an illusion, a false opinion is a delusion. Synonym: Delusion, mockery, deception, chimera, fallacy. Origin: F. Illusion, L. Illusio, fr. Illudere, illusum, to illude. Source: Websters Dictionary (01 Mar 1998) |
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| illusion of doubles | <syndrome> The delusional belief that a person (or persons) close to the schizophrenic patient has been substituted for by one or more impostors; may have an organic aetiology. Synonym: Capgras' phenomenon, illusion of doubles. (05 Mar 2000) |
| illusion of movement | Successive stimulation of neighboring retinal points which causes the sensation of movement. Oculogravic illusion, apparent movement of the visual field when the body is subjected to acceleration; due to gravity. Oculogyral illusion, an illusion occurring in angular acceleration in which the position of fixed light appears to drift. Optical illusion, a false interpretation of the colour, form, size, or movement of a visual sensation. (05 Mar 2000) |
| affect memory | The emotional element recurring whenever a significant experience is recalled. (05 Mar 2000) |
| anterograde memory | Memory for that which occurred after an event such as a brain injury. (05 Mar 2000) |
| remote memory | Memory for events of long ago as opposed to recent events. (05 Mar 2000) |
| retrograde memory | Memory for that which occurred before an event such as a brain injury. (05 Mar 2000) |
| memory | Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. (12 Dec 1998) |
| memory cell | <immunology> Cells of the immune system that do not respond immediately when it first encounters an antigen but facilitates the more rapid secondary response when the antigen is encountered on a subsequent occasion. The long lasting immune memory is humoral and resides in B-cells, although it appears that persistence of the antigen may be essential. T-cell memory is shorter. (14 Oct 1997) |
| memory disorder | Disturbances in registering an impression, in the retention of an acquired impression or in the recall of an impression. (12 Dec 1998) |
| memory loop | An electronic device for retrieving data that had been stored and/or displayed upon the oscilloscope at an earlier time; used for reviewing electrical events immediately preceding a specific disturbance. (05 Mar 2000) |
| memory span | The maximum number of items recalled after a single presentation (auditory or visual). (05 Mar 2000) |
| memory T-cell | A T-cell that bears receptors for a specific foreign antigen encountered during a prior infection or vaccination. After an infection or a vaccination, some of the T-cells that participated in the response remain as memory T-cells, which can rapidly mobilize and clone themselves should the same antigen be re-encountered during a second infection at a later time. (09 Oct 1997) |
| memory trace | See: engram. (05 Mar 2000) |
| screen memory | In psychoanalysis, a consciously tolerable memory that unwittingly serves as a cover for another associated memory which would be emotionally painful if recalled. (05 Mar 2000) |