Showing papers on "Latency (engineering) published in 1985"

An analysis of the strength-latency relationship.

Abstract: To account for latency in recognition memory, strength theory assumes that latency decreases symmetrically on both sides of the yes-no criterion. Some of the standard criticisms of the theory are presented. To evaluate these criticisms, explicit expressions for the latency distribution and its mean and variance were obtained. On analysis, the criticisms seem to be unwarranted. However, a satisfactory version of strength theory is not simple, and as many as a dozen or so parameters may be required to account for the data.

Future trends in pain research.

Abstract: In the future we shall need to modify the classical view that nerve impulses which signal the presence of injury are reliably transmitted by specified and automatic relay cells. We must investigate at least four different modifying mechanisms that are likely to generate chronic intractable pains. (1) With a latency of milliseconds , combinations of afferent signals and of descending controls operate a rapid and powerful gate control. (2) With a latency of minutes , impulses in C fibres change the excitability of peripheral endings and of spinal cord circuits. (3) With a latency of days , chemical transport in C fibres from areas of damage further modifies cord connectivity with a disappearance of inhibitions and an expansion of receptive fields. (4) With a latency of weeks and months , anatomical degeneration produces secondary changes in deafferented cells with atrophy, sprouting and abnormal firing patterns.

Auditory brain stem responses from human infants: Pure‐tone masking profiles for clicks and filtered clicks

Abstract: The effects of simultaneous pure‐tone maskers on ABR wave V latency and amplitude were examined in three‐month‐old infants as a means of delineating the frequency specificity of these responses in the immature auditory system. Masking profiles at two intensities (60 and 40 dBn HL) were obtained for click, as well as 4000‐ and 1000‐Hz filtered‐click stimuli. Infant profiles, obtained by measuring both latency and amplitude shifts as a result of the discrete‐frequency maskers, were compared to adult data obtained under an identical masking paradigm. Both latency and amplitude analyses showed masking profiles for infants which reveal greater low‐frequency contribution to responses than found in adult profiles. Additionally, the infant profiles reveal clear differences in the degree of high‐frequency spread of masking when comparisons are made to the adult data.

The effect of system workload on error latency: an experimental study

Abstract: In this paper, a methodology for determining and characterizing error latency is developed. The method is based on real workload data, gathered by an experiment instrumented on a VAX 11/780 during the normal workload cycle of the installation. This is the first attempt at jointly studying error latency and workload variations in a full production system. Distributions of error latency were generated by simulating the occurrence of faults under varying workload conditions. A family of error latency distributions so generated illustrate that error latency is not so much a function of when in time a fault occurred but rather a function of the workload that followed the failure. The study finds that the mean error latency varies by a 1 to 8 (hours) ratio between high and low workloads. The method is general and can be applied to any system.

Self-regulation of ICSS duration: Effects of anxiogenic substances, benzodiazepine antagonists and antidepressants

Abstract: A variety of anxiogenic substances, benzodiazepine antagonists and antidepressants were tested in a shuttlebox task in which rats interrupted infrared beams to initiate (ON latency) and terminate (OFF latency) continuous rewarding brain stimulation. It was hypothesized that substances exhibiting anxiogenic activity in animals (pentylenetetrazol and β-CCM) would selectively reduce the OFF latency, since anxiolytic drugs increase this latency. β-CCM, however, did not alter the OFF latency, but instead lengthened the ON latency. Pentylenetetrazol showed a similar, though not significant, trend. Ro 15-1788 did not alter ON latencies, but selectively lengthened the OFF latency at a high dose, consistent with previously reported anxiolytic activity at such doses. In contrast, CGS 8216 lengthened the ON latency selectively. Thus, Ro 15-1788 was differentiated from other drugs that antagonize benzodiazepines. Caffeine and dopamine uptake-blocking antidepressants (amineptine and nomifensine) preferentially decreased ON latencies, while non-dopamine-blocking antidepressants (viloxazine and CGS 7525A) lengthened both latencies nonspecifically. In conclusion, the OFF latency (but not the ON latency) appears refractory to reduction by various classes of psychotropic agents.

An algorithm for monitoring sensory evoked potentials.

Abstract: Brainstem auditory evoked potentials (BAEP) testing is used extensively to monitor auditory function during retromastoid craniectomies for microvascular decompression. The latency between BAEP peaks can change notably over a period of several seconds or minutes, a much shorter time than is necessary to acquire and analyze a conventionally averaged BAEP. This article describes a continuous monitoring algorithm that detects both large, rapid changes in waveform and slow changes in latency. A prestimulus control interval in the response data window provides a mechanism for evaluating the reliability of the response. The algorithm tracks the latency and amplitude of a selected peak, using several checks to avoid detecting the wrong peak. The tracking mechanism is simple yet effective and eliminates the need to suspend averaging for manual measurement of peak parameters. The peak latency and amplitude are displayed immediately. The algorithm indicates gross changes in the BAEP within 30 seconds and provides reliable data on latency trends. By increasing the frequency of acquiring new waveforms, the algorithm provides more immediate information for the surgeon.

Early auditory evoked potentials in spinocerebellar heredodegenerative involvement

Abstract: Results of early auditory evoked potentials, recorded during exploration of spinocerebellar heredodegenerative lesions (21 cases of Friedreich's disease, 8 cases of Pierre-Marie's disease and 3 cases of Strumpell-Lorraine disease), are analyzed. Tracings showed alteration of auditory BER whereas tonal audiometry was normal. Analysis of BER demonstrated lengthening of the latency periods, a rise in thresholds without latency period increases and a tracing that was sometimes flat or with waves that were difficult to recognize.

Herpes Simplex Virus Cycle: Model of Mechanism of Acute Disease, Latency and Reactivation

Abstract: The amazing secret of HSV survival for thousands of years and its adjustment to human organism still remain a mystery, and probably are due to the complex and almost perfect mechanism of latency and reactivations of the disease.