Stimulus presentation

Sensory perception is both quaUtative and quantitative. The taste of sucrose and the smell of linalool are two different kinds of sensory perceptions and each of these sensations can have different intensities. Sweet, bitter, salty, fmity, floral, etc, are different flavor quaUties produced by different chemical compounds the intensity of a particular sensory quaUty is deterrnined by the amount of the stimulus present. The saltiness of a sodium chloride solution becomes more intense if more of the salt is added, but its quaUty does not change. However, if hydrochloric acid is substituted for sodium chloride, the flavor quahty is sour not salty. For this reason, quaUty is substitutive, and quantity, intensity, or magnitude is additive (13). The sensory properties of food are generally compHcated, consisting of many different flavor quaUties at different intensities. The first task of sensory analysis is to identify the component quahties and then to determine their various intensities. 

Brockel, B. J., Cory-Slechta, D. A. (1999). The effects of postweaning low-level Pb exposure on sustained attention a study of target densities, stimulus presentation rate, and stimulus predictability. 

An individual who was blind in regard to the odour stimulus presented at each trial repeatedly viewed each test session and scored the following behavioural measures number of lateral head movements, number of hand-to-mouth movements, and frequency of sucking movements with the lips / mouth. 

The stimulus presentation method should be well adapted to avoid response variability as a result of response bias and other psychological factors. 

Similarity measures can also be obtained using a 10 point scale (e.g., from 1 to 10) or by obtaining confusabilities among triads. Odorants (or tastants) confused most frequently are considered more similar. Missing data designs can be used to reduce the number of actual stimulus presentations. 

Many government and commercial impairment testing systems can be implemented on standard commercially available personal computer platforms (e.g., PC, Macintosh). Despite software and hardware advancements that have minimized the differences across platforms, it is still important to consider carefully the hardware and software requirements needed to support a system, as these specifications may have important implications for the accuracy of stimulus presentation and the precision of performance measures. In addition, there may be differential costs associated with the hardware and software specifications. The speed of the computer processor is one important specification that requires careful consideration. Other concerns include the amount of memory that is needed to present the test and record the results, the manner in which the data are to be stored, the size and portability of the computer, and the video-display requirements. Some systems... 

Stimulus Presentation. Distilled water was allowed to flow continuously at a rate of 0.13-0.17 ml/sec over a gerbil s tongue, extended with a fine fishhook. Test solutions (2-4 ml) were alternated with the distilled water rinse without interruption of... 

LaPorte DJ, Blaxton TA, Michaelidis T, Robertson DU, Weiler MA, et al. 2005. Subtle effects of ketamine on memory when administered following stimulus presentation. Psychopharmacology 180 385-390. 

Uanagement of Test-Retest VariabiBty. One way to manage test-retest friability is to increase the size or intensity of the stimulus presented. However, this modification would be at the expense of sensitivity to change. That is, it would take a significantly greater degree of retinal... 

There is in inverse relationship between manifestation of opiate-induced respiratory depression and the degree of pain stimulus present. Thus, when analgesic effects decrease the pain stimulus at high doses, respiratory depression may suddenly be manifested. In the same way, respiratory depression induced by opiate overdose may be delayed by the induction of a painful stimulus. 

Distortion product otoacoustic emissions (DPOAEs) can be used to evaluate the function of the outer hair cells alone. DPOAEs are created as a by-product of outer hair cell motility following a specific stimulus presentation. When the basilar membrane moves in response to a sound, outer hair cells are stimulated and by electromotility aid in tuning specific frequencies to stimulate the inner hair cells... 

The VEP, like the electroretinogram, has several different forms, determine by the type of visual stimulus presented to the subject. The two most widely used in neurotoxic... 

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