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Summation

About: Summation is a research topic. Over the lifetime, 954 publications have been published within this topic receiving 45593 citations. The topic is also known as: summation & sum of a sequence.


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Journal ArticleDOI
TL;DR: This Discussion Paper seeks to kill off probability summation, specifically the high-threshold assumption, as an explanatory idea in visual science because it depends essentially on the 19th-century notion of a high fixed threshold.
Abstract: This Discussion Paper seeks to kill off probability summation, specifically the high-threshold assumption, as an explanatory idea in visual science. In combination with a Weibull function of a parameter of about 4, probability summation can accommodate, to within the limits of experimental error, the shape of the detectability function for contrast, the reduction in threshold that results from the combination of widely separated grating components, summation with respect to duration at threshold, and some instances, but not all, of spatial summation. But it has repeated difficulty with stimuli below threshold, because it denies the availability of input from such stimuli. All the phenomena listed above, and many more, can be accommodated equally accurately by signal-detection theory combined with an accelerated nonlinear transform of small, near-threshold, contrasts. This is illustrated with a transform that is the fourth power for the smallest contrasts, but tends to linear above threshold. Moreover, this particular transform can be derived from elementary properties of sensory neurons. Probability summation cannot be regarded as a special case of a more general theory, because it depends essentially on the 19th-century notion of a high fixed threshold. It is simply an obstruction to further progress.

18 citations

Journal ArticleDOI
TL;DR: It is suggested that adenosine mediates the high-temperature-induced depression of the excitatory synaptic transmission but not that of action potential propagation in rat CA1 neurons.

18 citations

Journal ArticleDOI
TL;DR: The results suggest that AS may exert its influence on pain processing at the supraspinal, rather than the spinal level, which is a contributing factor in acute and chronic pain.
Abstract: OBJECTIVES Anxiety sensitivity (AS) is the fear of anxiety-related sensations and its perceived harmful consequences. AS is associated with enhanced pain and worsened pain outcomes, suggesting it is a contributing factor in acute and chronic pain. However, the mechanisms that mediate the relationship between AS and pain are currently unknown. This study assessed the relationship between AS and 2 measures of spinal nociceptive processes (ie, nociceptive flexion reflex and temporal summation of nociceptive flexion reflex) and measures of subjective pain. This allowed us to determine whether AS engages descending cerebrospinal processes to facilitate pain signaling at spinal levels. METHODS AS was assessed in healthy men and women using the Anxiety Sensitivity Index-Revised. Then pain processing was assessed from electric pain threshold, nociceptive flexion reflex threshold, temporal summation of pain, temporal summation of nociceptive flexion reflex, and McGill Pain Questionnaire sensory and affective pain ratings. Associations among variables were assessed using Winsorized correlations (a robust and statistically powerful analytic method). RESULTS AS was positively associated with sensory pain ratings, affective pain ratings, and temporal summation of pain, but was unrelated to all other outcomes. DISCUSSION Given that AS was not significantly associated with measures of spinal nociception, these results suggest that AS may exert its influence on pain processing at the supraspinal, rather than the spinal level.

18 citations

Journal ArticleDOI
01 May 2015-Pain
TL;DR: Enhanced responsiveness to evoked thermal pain in African Americans is present in adolescence but is unlikely to be related to elevated TSSP, which may have implications for understanding racial differences in chronic pain experience in adulthood.
Abstract: Racial differences in pain responsiveness have been demonstrated in adults. However, it is unclear whether racial differences are also present in youth and whether they extend to experimental pain indices assessing temporal summation of second pain (TSSP). Temporal summation of second pain provides an index of pain sensitivity and may be especially relevant in determining risk for chronic pain. This study assessed pain tolerance and TSSP to evoked thermal pain in 78 healthy youth (age range, 10-17), 51% of whom were African American and 49% were non-Hispanic white. Multilevel models revealed within-individual increases in pain ratings during the temporal summation task in non-Hispanic white youth that were consistent with TSSP. Pain ratings did not change significantly during the temporal summation task in African-American youth. Baseline evoked pain ratings were significantly higher in African-American compared with non-Hispanic white youth. These findings suggest that enhanced responsiveness to evoked thermal pain in African Americans is present in adolescence but is unlikely to be related to elevated TSSP. These results may have implications for understanding racial differences in chronic pain experience in adulthood.

18 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202323
202234
202118
20204
201911
201812