Perception of duration in the parvocellular system

Abstract

Both theoretical and experimental evidence suggests that duration perception is mediated preferentially by the color-blind but high temporally sensitive luminance pathway. In this experiment we tested whether color modulated stimuli and high spatial frequency luminance modulated stimuli, which are known to be relayed mostly by the slow parvocellular system, are able to elicit reliable sense of duration. We show that ramped color modulated stimuli seem to last less than luminance modulated stimuli matched for visibility. The effect is large, about 200 ms and is constant at all durations tested (range 500–1100 ms). However, high spatial frequency luminance stimuli obtain duration matches similar to those of low spatial frequency luminance modulated stimuli. The results at various levels of contrast and temporal smoothing indicate that equiluminant stimuli have higher contrast thresholds to activate the mechanisms which time visual stimuli. Overall the results imply that both the magnocellular and the parvocellular systems access reliably the timing mechanisms with a difference only in the way these are engaged.

Duration perception for visual stimuli is impaired in dyslexia but deficits in visual processing may not be the culprits

“…The idea that luminance contrast and/or motion processing are impaired in dyslexia is mainly associated with the magnocellular deficit hypothesis 12 , 13 , according to which a deficit in one of the two major pathways of the visual system 14 , i.e., the magnocellular visual pathway (M-pathway) 15 , 16 , contributes significantly to reading difficulties 17 . Note that deficits in the complementary, parvocellular pathway have also been hypothesized both as causes of duration perception deficits 18 , and as important deficits in dyslexia 11 , 19 , but these views are compatible as far as the relevance of visual processing skills in time perception is concerned. Among the multiple tasks that have been designed to capture deficits in the M-pathway, those addressing (1) contrast sensitivity to transient, low-luminance stimuli at low spatial frequencies or (2) sensitivity to dynamic changes in motion 20 , 21 gained prominence.…”

Multiple channels of visual time perception

“…These experimental conditions again point to a critical role of the magnocellular pathway. This does not imply that the parvocellular pathway is not involved in the processing of subsecond intervals [39]. There is some evidence that adaptation causes changes in apparent duration when the adaptor contains translating motion, but not when it contains radial, circular or biological motion [40].…”

Neon color spreading in dynamic displays: Temporal factors

“…The difference between the time course for the black rays and the red star may be explained by the observation that luminance-modulated stimuli are processed faster than color-modulated stimuli (Breitmeyer, 1975;Burr & Corsale, 2001;Burr & Morrone, 1996;Cicchini, 2012;McKeefry, Parry, & Murray, 2003). An estimate of the temporal constants of the channels processing the star and the rays may be obtained by fitting the data with a standard saturating function akin to the Naka-Rushton equation…”