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Visual Contextual Effects of Orientation, Contrast, Flicker, and Luminance: All Are Affected by Normal Aging.

Nguyen BN, McKendrick AM - Front Aging Neurosci (2016)

Bottom Line: The perception of a visual stimulus can be markedly altered by spatial interactions between the stimulus and its surround.Such center-surround interactions in visual perception are numerous and arise from both cortical and pre-cortical neural circuitry.Here, we compare the perception of older and younger observers on a battery of tasks designed to assess such visual contextual effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Optometry and Vision Sciences, University of Melbourne, Parkville VIC, Australia.

ABSTRACT
The perception of a visual stimulus can be markedly altered by spatial interactions between the stimulus and its surround. For example, a grating stimulus appears lower in contrast when surrounded by a similar pattern of higher contrast: a phenomenon known as surround suppression of perceived contrast. Such center-surround interactions in visual perception are numerous and arise from both cortical and pre-cortical neural circuitry. For example, perceptual surround suppression of luminance and flicker are predominantly mediated pre-cortically, whereas contrast and orientation suppression have strong cortical contributions. Here, we compare the perception of older and younger observers on a battery of tasks designed to assess such visual contextual effects. For all visual dimensions tested (luminance, flicker, contrast, and orientation), on average the older adults showed greater suppression of central targets than the younger adult group. The increase in suppression was consistent in magnitude across all tasks, suggesting that normal aging produces a generalized, non-specific alteration to contextual processing in vision.

No MeSH data available.


Related in: MedlinePlus

The relationship between strength of surround suppression across the different tasks. Pearson correlation coefficients are shown for the two groups combined. (A) Flicker versus luminance (B) Orientation versus luminance (C) Contrast versus luminance (D) Contrast versus flicker (E) Orientation versus flicker (F) Orientation versus contrast.
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Figure 5: The relationship between strength of surround suppression across the different tasks. Pearson correlation coefficients are shown for the two groups combined. (A) Flicker versus luminance (B) Orientation versus luminance (C) Contrast versus luminance (D) Contrast versus flicker (E) Orientation versus flicker (F) Orientation versus contrast.

Mentions: Does stronger suppression on one task predict stronger suppression on other tasks? Given that visual contextual performance is relatively uniform within each age group (younger versus older), we pooled the data from the two groups to obtain a range of suppressive strengths in the presence of a surround. Figure 5 depicts the inter-task Pearson correlation analyses across the entire dataset based on the suppression indices, which takes into consideration baseline (no surround) performance. Statistical significance was defined at an alpha level starting at 0.008 (α1, Holm–Bonferroni correction), given there were six multiple comparisons. Under this criterion, we found a statistically significant positive correlation between contrast and orientation suppression (Figure 5F; Pearson r = 0.45, R2 = 0.21, p = 0.0076). Similarly, although these did not reach statistical significance based on sequential multiple comparisons (α2 = 0.01, α3 = 0.013), trends for a positive relationship between luminance and contrast suppression (Figure 5C; Pearson r = 0.41, R2 = 0.17, p = 0.014), and luminance and flicker suppression (Figure 5A; Pearson r = 0.38, R2 = 0.14, p = 0.038), were also observed. Table 1 shows the correlation analyses for each group (younger and older) separately. None of these reached statistical significance once the 12 multiple comparisons were considered.


Visual Contextual Effects of Orientation, Contrast, Flicker, and Luminance: All Are Affected by Normal Aging.

Nguyen BN, McKendrick AM - Front Aging Neurosci (2016)

The relationship between strength of surround suppression across the different tasks. Pearson correlation coefficients are shown for the two groups combined. (A) Flicker versus luminance (B) Orientation versus luminance (C) Contrast versus luminance (D) Contrast versus flicker (E) Orientation versus flicker (F) Orientation versus contrast.
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Related In: Results  -  Collection

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Figure 5: The relationship between strength of surround suppression across the different tasks. Pearson correlation coefficients are shown for the two groups combined. (A) Flicker versus luminance (B) Orientation versus luminance (C) Contrast versus luminance (D) Contrast versus flicker (E) Orientation versus flicker (F) Orientation versus contrast.
Mentions: Does stronger suppression on one task predict stronger suppression on other tasks? Given that visual contextual performance is relatively uniform within each age group (younger versus older), we pooled the data from the two groups to obtain a range of suppressive strengths in the presence of a surround. Figure 5 depicts the inter-task Pearson correlation analyses across the entire dataset based on the suppression indices, which takes into consideration baseline (no surround) performance. Statistical significance was defined at an alpha level starting at 0.008 (α1, Holm–Bonferroni correction), given there were six multiple comparisons. Under this criterion, we found a statistically significant positive correlation between contrast and orientation suppression (Figure 5F; Pearson r = 0.45, R2 = 0.21, p = 0.0076). Similarly, although these did not reach statistical significance based on sequential multiple comparisons (α2 = 0.01, α3 = 0.013), trends for a positive relationship between luminance and contrast suppression (Figure 5C; Pearson r = 0.41, R2 = 0.17, p = 0.014), and luminance and flicker suppression (Figure 5A; Pearson r = 0.38, R2 = 0.14, p = 0.038), were also observed. Table 1 shows the correlation analyses for each group (younger and older) separately. None of these reached statistical significance once the 12 multiple comparisons were considered.

Bottom Line: The perception of a visual stimulus can be markedly altered by spatial interactions between the stimulus and its surround.Such center-surround interactions in visual perception are numerous and arise from both cortical and pre-cortical neural circuitry.Here, we compare the perception of older and younger observers on a battery of tasks designed to assess such visual contextual effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Optometry and Vision Sciences, University of Melbourne, Parkville VIC, Australia.

ABSTRACT
The perception of a visual stimulus can be markedly altered by spatial interactions between the stimulus and its surround. For example, a grating stimulus appears lower in contrast when surrounded by a similar pattern of higher contrast: a phenomenon known as surround suppression of perceived contrast. Such center-surround interactions in visual perception are numerous and arise from both cortical and pre-cortical neural circuitry. For example, perceptual surround suppression of luminance and flicker are predominantly mediated pre-cortically, whereas contrast and orientation suppression have strong cortical contributions. Here, we compare the perception of older and younger observers on a battery of tasks designed to assess such visual contextual effects. For all visual dimensions tested (luminance, flicker, contrast, and orientation), on average the older adults showed greater suppression of central targets than the younger adult group. The increase in suppression was consistent in magnitude across all tasks, suggesting that normal aging produces a generalized, non-specific alteration to contextual processing in vision.

No MeSH data available.


Related in: MedlinePlus