Effects of stimulus size, eccentricity, luminance, and attention on pupillary light response examined by concentric stimulus

Hu, Xiaofei; Hisakata, Rumi

doi:10.1016/j.visres.2020.03.008

Cited by 7 publications

(14 citation statements)

References 64 publications

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“…We hypothesized that the influence of luminance on pupil size would be greatest for pixels near the fovea and would reduce with eccentricity in a radial manner. This hypothesis is consistent with previous work indicating that the strength of the PLR is reduced as a function of eccentricity (Crawford and Parsons, 1936;Legras et al, 2018;Hu et al, 2020), which may be attributed to the diminishing distribution of photoreceptors farther away from the fovea. We also hypothesized that the relationship between luminance and pupil size would vary by wavelength, consistent with prior work indicating that blue colored light is perceived as being brighter (Suzuki et al, 2019) and can have a distinct influence on the PLR (Bonmati-Carrion et al, 2016).…”

Section: Introductionsupporting

confidence: 93%

“…We hypothesized a foveal bias in the correlation maps, consistent with research showing that stimuli nearer to fovea induce stronger PLRs than stimuli in the periphery (Crawford and Parsons, 1936;Legras et al, 2018;Hu et al, 2020). This prediction is also related to the structure of the human visual system as the distribution of photoreceptors changes dramatically as a function of distance from the fovea, and there are significant differences in visual function between foveal, parafoveal, and the peripheral regions (Preuschoff et al, 2011;Strasburger et al, 2011).…”

Section: No Fovea Biassupporting

confidence: 76%

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“Blue Sky Effect”: Contextual Influences on Pupil Size During Naturalistic Visual Search

et al. 2021

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Pupil size is influenced by cognitive and non-cognitive factors. One of the strongest modulators of pupil size is scene luminance, which complicates studies of cognitive pupillometry in environments with complex patterns of visual stimulation. To help understand how dynamic visual scene statistics influence pupil size during an active visual search task in a visually rich 3D virtual environment (VE), we analyzed the correlation between pupil size and intensity changes of image pixels in the red, green, and blue (RGB) channels within a large window (~14 degrees) surrounding the gaze position over time. Overall, blue and green channels had a stronger influence on pupil size than the red channel. The correlation maps were not consistent with the hypothesis of a foveal bias for luminance, instead revealing a significant contextual effect, whereby pixels above the gaze point in the green/blue channels had a disproportionate impact on pupil size. We hypothesized this differential sensitivity of pupil responsiveness to blue light from above as a “blue sky effect,” and confirmed this finding with a follow-on experiment with a controlled laboratory task. Pupillary constrictions were significantly stronger when blue was presented above fixation (paired with luminance-matched gray on bottom) compared to below fixation. This effect was specific for the blue color channel and this stimulus orientation. These results highlight the differential sensitivity of pupillary responses to scene statistics in studies or applications that involve complex visual environments and suggest blue light as a predominant factor influencing pupil size.

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Section: Introductionsupporting

confidence: 93%

Section: No Fovea Biassupporting

confidence: 76%

“Blue Sky Effect”: Contextual Influences on Pupil Size During Naturalistic Visual Search

et al. 2021

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“…This indicates a non-linear relation to stimulus size while the relation to the logarithm of stimulus size is negatively linear. These observations are in line with the results of Cibis et al and Hu et al: Cibis et al found shorter latencies for larger stimuli and additionally a negative linear relation between the logarithm of the stimulus intensity and the pupillomotor latency [40] and Hu et al determined latency to be a function of CFD [22]. In ERG, a faster b-wave can be determined with increasing light for both rods and cones [34] which is consistent with our results as well.…”

Section: Discussionsupporting

confidence: 93%

Effect of central and peripheral cone- and rod-specific stimulation on the pupillary light reflex

et al. 2021

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Purpose To assess the effect of central and peripheral stimulation on the pupillary light reflex. The aim was to detect possible differences between cone- and rod-driven reactions. Methods Relative maximal pupil constriction amplitude (relMCA) and latency to constriction onset (latency) to cone- and rod-specific stimuli of 30 healthy participants (24 ± 5 years (standard deviation)) were measured using chromatic pupil campimetry. Cone- and rod-specific stimuli had different intensities and wavelengths according to the Standards in Pupillography. Five filled circles with radii of 3°, 5°, 10°, 20° and 40° and four rings with a constant outer radius of 40° and inner radii of 3°, 5°, 10° and 20° were used as stimuli. Results For cone-and rod-specific stimuli, relMCA increased with the stimulus area for both, circles and rings. However, increasing the area of a cone-specific ring by minimizing its inner radius with constant outer radius increased relMCA significantly stronger than the same did for a rod-specific ring. For cones and rods, a circle stimulus with a radius of 40° created a lower relMCA than the summation of the relMCAs to the corresponding ring and circle stimuli which combined create a 40° circle-stimulus. Latency was longer for rods than for cones. It decreased with increasing stimulus area for circle stimuli while it stayed nearly constant with increasing ring stimulus area for cone- and rod-specific stimuli. Conclusion The effect of central stimulation on relMCA is more dominant for cone-specific stimuli than for rod-specific stimuli while latency dynamics are similar for both conditions.

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“…It is essential to understand that the PLR is not a linear reaction of the pupil to light because pupil size is dramatically confounded by modest changes in attention, accommodation, and environmental ambient light [4]. The attentional state of an individual, along with the size, luminance, and eccentricity of a stimulus, contributes to what was previously Life 2021, 11, 1104 2 of 24 considered a simple reflex [5]. The PLR has been widely used to evaluate the activity of the autonomic nervous system [6].…”

Section: Introductionmentioning

confidence: 99%

The Pupillary Light Reflex as a Biomarker of Concussion

Frederick

Azzolino

Hunfalvay

et al. 2021

Life

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The size of our pupils changes continuously in response to variations in ambient light levels, a process known as the pupillary light reflex (PLR). The PLR is not a simple reflex as its function is modulated by cognitive brain function and any long-term changes in brain function secondary to injury should cause a change in the parameters of the PLR. We performed a retrospective clinical review of the PLR of our patients using the BrightLamp Reflex iPhone app. The PLR variables of latency, maximum pupil diameter (MaxPD), minimum pupil diameter (MinPD), maximum constriction velocity (MCV), and the 75% recovery time (75% PRT) were associated with significant differences between subjects who had suffered a concussion and those that had not. There were also significant differences in PLR metrics over the life span and between genders and those subjects with and without symptoms. The differences in PLR metrics are modulated not only by concussion history but also by gender and whether or not the person has symptoms associated with a head injury. A concussive injury to the brain is associated with changes in the PLR that persist over the life span, representing biomarkers that might be used in clinical diagnosis, treatment, and decision making.

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Effects of stimulus size, eccentricity, luminance, and attention on pupillary light response examined by concentric stimulus

Cited by 7 publications

References 64 publications

“Blue Sky Effect”: Contextual Influences on Pupil Size During Naturalistic Visual Search

“Blue Sky Effect”: Contextual Influences on Pupil Size During Naturalistic Visual Search

Effect of central and peripheral cone- and rod-specific stimulation on the pupillary light reflex

The Pupillary Light Reflex as a Biomarker of Concussion

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