Perceived Intensity of Odor as a Function of Time of Adaptation

Ekman, Gösta; Berglund, Birgltta; Berglund, Ulf; Lindvall, Thomas

doi:10.1037/e611292010-001

Cited by 55 publications

(72 citation statements)

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“…Then his task was to identify the bottle containing the strongest odor. Subjects began at the lowest dilutional step (Step 9) in order to avoid adaptation (Ekman et al, 1967). Incorrect choices led to presentation of a higher concentration.…”

Section: Odor Threshold Testmentioning

confidence: 99%

“…Odors are presented individually for 5 s with a 45-s interstimulus interval to minimize adaptation (Ekman et al, 1967). The participant smells each odor, with the eyes closed to prevent visual cues, and then attempts to name it with the aid of a cue sheet that contains line drawings of the items as well as distractors.…”

Section: San Diego Odor Identification Testmentioning

confidence: 99%

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Left hippocampal volume loss in Alzheimer's disease is reflected in performance on odor identification: A structural MRI study

Murphy

Jernigan

Fennema-Notestine

2003

J Int Neuropsychol Soc

121

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The very high sensitivity and specificity of odor identification tasks in discriminating between Alzheimer's patients and normals suggests that they reflect the presence of underlying neuropathology. Significant neuropathological changes are seen in areas critical to processing olfactory information, even in the early stages of Alzheimer's disease (AD). The current study was designed to investigate whether performance on olfactory tasks (odor threshold and odor identification) was related to volumetric MRI measures of mesial temporal areas central to olfactory information processing and important in the neuropathology of AD. Participants were 8 male and 5 female patients with probable AD, and 10 male and 12 female normal age-matched controls, diagnosed at the UCSD Alzheimer's Disease Research Center. The study investigated correlations between volumetric measures of hippocampus, the parahippocampal gyrus and the amygdala, and the psychophysical measures of olfactory function. Robust relationships were observed between mesial temporal lobe volumes and olfactory functional measures. The finding of a strong relationship between left hippocampal volume and performance on the odor identification task (r 5 .85) is compatible with a left-hemisphere superiority for verbally mediated olfactory tasks. The findings suggest a neural substrate for the breakdown in functional performance on verbally mediated odor identification tasks in Alzheimer's disease and suggest the utility of quantitative MRI measures and psychophysical performance in the assessment of AD. These results support the potential clinical utility of inclusion of odor identification tests in diagnostic batteries for detecting AD. (JINS, 2003, 9, 459-471.)

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Section: Odor Threshold Testmentioning

confidence: 99%

Section: San Diego Odor Identification Testmentioning

confidence: 99%

Left hippocampal volume loss in Alzheimer's disease is reflected in performance on odor identification: A structural MRI study

Murphy

Jernigan

Fennema-Notestine

2003

J Int Neuropsychol Soc

121

View full text Add to dashboard Cite

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“…Each curve represented the average of 10 sets of trials, and the coordinates were given for every I % step in the target percentage. Finger spans were originally generated in 10% increments from 5% to 95% ofthe maximum, but I used the coordinates at 10% intervals from 10% to 90% to make the data commensurate with those of Ekman et al (1967).…”

Section: Notesmentioning

confidence: 99%

“…Although not a study of finger span per se, subjects in the experiments of Ekman, Berglund, Berglund, and Lindvall (1967) and Berglund and Olsson (1993) used finger span to indicate perceived odor strength. Finger span was measured with the thumb fixed and the index finger in a sliding carriage attached to a linear potentiometer.…”

mentioning

confidence: 99%

“…These functions were then inverted and used to convert the finger spans generated in response to olfactory stimuli into normalized numerical values. The results from Ekman et al (1967, Figure 2), as well as the unpublished data from Berglund and Olsson (1993, personal communication), are plotted in Figure 2, with the target percentage on the ordinate and the resulting span on the abscissa. Each thin line is the average of 10 trials from 1 of 16 subjects (8 from each study).…”

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confidence: 99%

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Cross-modality matches of finger span and line length

Doren

1995

Perception & Psychophysics

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Perceived finger span-the perceived spatial separation between the tip ofthe thumb and the tip of the index finger-was measured by using cross-modal matching to line length. In the first experiment, subjects adjusted finger span to match the length of line segments presented on a video monitor, and conversely, with both hands. Subjects also made estimates of finger span in physical units ("dead reckoning"). Finger spans were measured by using infrared LEDs mounted on the tip of the thumb and the finger tip, so the hand made no contact with any object during the experiment. Unlike in previous studies, the results suggest that perceived finger span is proportional to line length and slightly shorter than the actual span, provided that corrections are made for regression bias. The effect of finger contact was assessed in a second experiment by matching line length both to free span and to spans constrained by the pinching of blocks in the same session. The matching function when subjects were pinching blocks was accelerating, consistent with previous reports. In contrast, matched line length was a decelerating function of free span. The exponent of the free span matching function in the second experiment was slightly smaller than in the first experiment, probably due to uncorrected matching biases in the second experiment.A person usually has no difficulty reaching for a glass of water and picking it up. It can be done even with the eyes closed after a couple of tries. There is, obviously, exquisite motor control based on visual and somatosensory information. But do the different sensory modalities tell us the same thing? For example, does the glass look as big as it feels? The question does not seem that interesting at first-surely the perceived size of the glass does not depend on whether it is looked at or is held in the hand. Experimentally, though, the answer depends on how the equivalence of size is measured. Magnitude estimates of span are nearly linear with respect to the actual distance between the tips of the index fingers of two hands held apart (Gogel, Wist, & Harker, 1963;Stanley, 1966;M. Teghtsoonian & R. Teghtsoonian, 1965). But the bulk of the experimental evidence suggests in contrast that the span perceived between the tips of the thumb and index finger of the same hand is a nonlinear function of the actual distance, is not veridical, and is not commensurate with perceived visual size.Jastrow (1886) provided the first such evidence by having subjects adjust finger span by sliding a movable carriage held between the thumb and index finger to match the length ofa viewed line (0.5-12 ern); or, to seThe author would like to thank Robert Teghtsoonian and Calvin Garbin for reviewing the manuscript and making many helpful comments and suggestions; Purwanto Suwondo, Lisa Menia, Jennifer Evans, and Michael Haines for technical assistance and data collection; and Robert Montz for making the blocks used in the second experiment. This work was funded by Grant NS27958 from the National Institutes of Health. Co...

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