Development of face discrimination abilities, and relationship to magnocellular pathway development, between childhood and adulthood

AbstractThe current study tested the development of face and object processing in young children (mean age = 5.24 years), adolescents (mean age = 15.8 years), and adults (mean age = 21.1 years) using stimuli that were equated for low-level visual characteristics (luminance, contrast, and spatial frequency make-up) and methods that equate for difficulty across ages. We also tested sensitivity to luminance and chromatic contrast (i.e., thought to be mediated primarily by the subcortical Magnocellular (M) and Parvocellular (P) pathways, respectively) to determine whether age-related improvements in face or object discrimination were driven by age-related changes in the M and/or P pathways. Results showed a selective age-related improvement in face sensitivity and a relationship between age-related increases in face sensitivity and luminance contrast sensitivity. These results add to the mounting evidence that the M pathway may influence face processing.

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Spatial Integration of Objectively Equiluminous Chromatic Gratings

Perception ◽

10.1068/v970297 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 200-200

Author(s):

M I Kankaanpää ◽

J Rovamo ◽

H T Kukkonen ◽

J Hallikainen

Keyword(s):

Spatial Frequency ◽

Contrast Sensitivity ◽

Spatial Integration ◽

Chromatic Contrast ◽

Shape Difference ◽

Sensitivity Functions ◽

Spatial Frequencies ◽

Low Pass ◽

Chromatic Aberrations ◽

Chromatic Contrast Sensitivity

Contrast sensitivity functions for achromatic and chromatic gratings tend to be band-pass and low-pass in shape, respectively. Our aim was to test whether spatial integration contributes to the shape difference found at low spatial frequencies. We measured binocular chromatic contrast sensitivity as a function of grating area for objectively equiluminous red - green and blue - yellow chromatic gratings. Chromatic contrast refers to the Michelson contrast of either of the two chromatic component gratings presented in counterphase against the combined background. Grating area ( A) varied from 1 to 256 square cycles ( Af2) at spatial frequencies ( f) of 0.125 – 4.0 cycles deg−1. We used only horizontal gratings at low and medium spatial frequencies to minimise the transverse and longitudinal chromatic aberrations due to ocular optics. At all spatial frequencies studied, chromatic contrast sensitivity increased with grating area. Ac was found to be constant at low spatial frequencies (0.125 – 0.5 cycles deg−1) but decreased in inverse proportion to increasing spatial frequency at 1 – 4 cycles deg−1. Thus, spatial integration depends similarly on spatial frequency for achromatic (Luntinen et al, 1995 Vision Research35 2339 – 2346) and chromatic gratings, and differences in spatial integration do not contribute to the shape difference of the respective contrast sensitivity functions.

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Age-related changes of defocus-specific contrast sensitivity in healthy subjects

Ophthalmic and Physiological Optics ◽

10.1046/j.1475-1313.2000.00539.x ◽

2000 ◽

Vol 20 (4) ◽

pp. 323-334 ◽

Cited By ~ 27

Author(s):

Y. K. Nio ◽

N. M. Jansonius ◽

V. Fidler ◽

E. Geraghty ◽

S. Norrby ◽

...

Keyword(s):

Contrast Sensitivity ◽

Healthy Subjects ◽

Age Related ◽

Age Related Changes

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Age-related changes in suprathreshold contrast perception in the upper and lower visual field: Effects of temporal/spatial frequency and contrast

Journal of Vision ◽

10.1167/12.9.472 ◽

2012 ◽

Vol 12 (9) ◽

pp. 472-472

Author(s):

L. Leone ◽

B. Blakeslee ◽

M. E. McCourt

Keyword(s):

Visual Field ◽

Spatial Frequency ◽

Lower Visual Field ◽

Field Effects ◽

Age Related ◽

Contrast Perception ◽

Age Related Changes

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The Binocular Summation of Chromatic Contrast

Perception ◽

10.1068/v96l0409 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 145-145 ◽

Cited By ~ 1

Author(s):

D R Simmons ◽

F A A Kingdom

Keyword(s):

Contrast Sensitivity ◽

Detection Threshold ◽

Luminance Contrast ◽

Binocular Summation ◽

Chromatic Contrast ◽

Probability Summation ◽

Investigative Ophthalmology ◽

Contrast Thresholds ◽

Detection Mechanisms ◽

Neural Summation

The level of binocularity possessed by mechanisms sensitive to chromatic contrast is still unclear. Recent studies of stereopsis and chromatic contrast have suggested that stereopsis is maintained at isoluminance, although the contrast sensitivity and disparity ranges of chromatic stereopsis mechanisms are reduced compared to luminance stereopsis mechanisms. Rose, Blake, and Halpern (1988 Investigative Ophthalmology and Visual Science29 283 – 290) hypothesised a link between binocular summation (ie the superiority of binocular detection over monocular detection) and stereopsis. Is this link maintained with heterochromatic isoluminant stimuli? To address this question, the binocular and monocular contrast thresholds for the detection of 0.5 cycle deg−1 Gabor patches were measured. The stimuli possessed different relative amounts of colour and luminance contrast ranging from isoluminance (red/green) to isochrominance (yellow/black) through intermediate values. It was found that, with these stimuli, binocular detection was well modelled by assuming independent mechanisms sensitive to chromatic contrast and luminance contrast. Furthermore, with isoluminant stimuli, levels of binocular summation were above those expected from probability summation between the eyes, thus providing evidence for binocular neural summation within chromatic detection mechanisms. Given that stereoscopic depth identification is impossible at contrast detection threshold with isoluminant heterochromatic stimuli, these results suggest that the link between stereopsis and levels of binocular neural summation may not be a particularly strong one. These results also provide clear evidence for the binocularity of chromatic detection mechanisms.

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