Changes in scotopic flicker fusion intensity (cffi) in squirrel monkeys exposed to methyl mercury
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Changes in scotopic flicker fusion intensity (cffi) in squirrel monkeys exposed to methyl mercury by Jan Hellberg

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Published by Lund University in Lund, Sweden .
Written in English


  • Flicker fusion.,
  • Visual evoked response.,
  • Physiological optics.

Book details:

Edition Notes

Statementby Jan Hellberg and Jonas Hellström.
SeriesPsychological research bulletin -- XVII:12 1977., Psychological research bulletin -- 1977 XVII:12.
ContributionsHellström, Jonas.
The Physical Object
Pagination12 p. :
Number of Pages12
ID Numbers
Open LibraryOL16563664M

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Contrast sensitivity functions for flicker; relate modulation depth detection thresholds to the temporal frequency of a flickering light. cutoff frequency near 60 Hz. high and low frequency "falloff" little or no low-frequency falloff under scotopic viewing conditions maximum (photopic) sensitivity between 5 - 20 Hz.   The eye can function over a large range of luminance levels; it must also be able to handle the different rates of change in luminance. Our eyes are constantly sampling information of images projected onto the retina in a periodic manner. Information is then integrated so objects around us appear to be stable or move smoothly. Because there is a finite amount of time .   Single flashes of double intensity (∼ Td • s) were also presented as a reference. Visual responses to flash pairs were measured via (1) recording of the ERG b-wave, and (2) threshold determinations of the CFF using a twoalternative forced-choice method (flicker vs. fused illumination).Cited by: 2.   Flicker data obtained with a constant high intensity stimulus from a fully dark-adapted patient can be related to both scotopic and photopic function. Scotopic responses are obtained at slower and photopic responses at faster frequencies. The use of numerous frequencies in sequence presents a method of quantitating flicker data; thus, responses from Cited by: 9.

However, there is a range of intermediate ambient light intensity in which both systems are working. This intermediate zone is said to be mesopic vision. In this illustration, we will take a simple photograph and simulate the differences between photopic and scotopic vision, starting with the lack of color vision in scotopic vision.   Humans perceive a stable average intensity image without flicker artifacts when a television or monitor updates at a sufficiently fast rate. Cited by:   Critical flicker fusion occurs when the observer can no longer distinguish between changing visual stimuli, like two colors of light flickering at increasing frequencies, the . Changes in scotopic flicker fusion intensity (cffi) in squirrel monkeys exposed to methyl mercury / by Jan Hellberg and Jonas Hellström. BF 21 A1 P75 The meta-contrast technique (MCT) as a test of anxiety in childhood and adolescence / by .

However, when special care is taken to selectively desensitize the cones and thus, reveal the rod function under bright illumination, flicker fusion frequencies are achieved at 28Hz (Conner and MacLeod, ). In ERG recording, CFF is determined by the frequency of photic stimulation that just elicits flickering electrical signal. Other articles where Flicker-fusion frequency is discussed: movement perception: Apparent movement: occurs is called the perceiver’s flicker-fusion frequency (or critical flicker frequency) and represents the temporal resolving power of his visual system at the time. Another process on which apparent movement depends is a tendency (called visual closure or phi) to fill in the . As FFF increases with increases in light intensity, the maximum or critical flicker fusion frequency (CFF), which is the highest flicker fusion frequency at any light intensity is often reported. CFF has been used to compare the temporal resolution capabilities of different animals (e.g. Jenssen and Swenson, , Ordy and Samorajski, ).Cited by: Critical Flicker Fusion Frequency (CFFF) arouses the interest of researchers in different areas like medicine, physiology, and psychology. In medicine and physiology, CFFF is treated as an indicator of physiological changes in the human after the use of drugs or alcohol (Jansen, de Gier, & Slanger, , ; Weber, Jeremini, & Grandjean, ).