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Global motion percept mediated through integration of barber poles presented in bilateral visual hemifields.

Huang LT, Wong AM, Chen CP, Chang WH, Cheng JW, Lin YR, Pei YC - PLoS ONE (2013)

Bottom Line: Surprisingly, when the inter-component distance between the two apertures was short, the perceived direction of motion of the dual barber poles was similar to that of a single barber pole formed by the concatenation of the two component barber poles, indicating motion integration is achieved through a simple concatenation mechanism.We found that integration is achieved only when phase, speed, wavelength, temporal frequency, and duty cycle are identical in the two barber poles, but can remain robust when the contrast of the two component barber poles differs substantially.We concluded that a motion stimulus presented in bilateral hemifields tends to be integrated to yield a global percept with a substantial tolerance for spatial distance and contrast difference.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.

ABSTRACT
How is motion information that has been obtained through multiple viewing apertures integrated to form a global motion percept? We investigated the mechanisms of motion integration across apertures in two hemifields by presenting gratings through two rectangles (that form the dual barber poles) and recording the perceived direction of motion by human observers. To this end, we presented dual barber poles in conditions with various inter-component distances between the apertures and evaluated the degree to which the hemifield information was integrated by measuring the magnitude of the perceived barber pole illusion. Surprisingly, when the inter-component distance between the two apertures was short, the perceived direction of motion of the dual barber poles was similar to that of a single barber pole formed by the concatenation of the two component barber poles, indicating motion integration is achieved through a simple concatenation mechanism. We then presented dual barber poles in which the motion and contour properties of the two component barber poles differed to characterize the constraints underlying cross-hemifield integration. We found that integration is achieved only when phase, speed, wavelength, temporal frequency, and duty cycle are identical in the two barber poles, but can remain robust when the contrast of the two component barber poles differs substantially. We concluded that a motion stimulus presented in bilateral hemifields tends to be integrated to yield a global percept with a substantial tolerance for spatial distance and contrast difference.

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Related in: MedlinePlus

The perceived directions of the dual barber poles in which the duty cycle of the two component barber poles differed.A. Three example dual barber poles with the duty cycle of the left component barber pole 2/3 times (upper panel), equal (middle panel), or 3/2 times (lower panel) that of the right component barber pole (duty cycle = 50%). B–C. The probability of perceiving a global motion observed in an example subject (B) and in the mean across subjects (C). D–E. The perceptual bias observed in an example subject (D) and in the mean across subjects (E). *: p < 0.05 across conditions.
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pone-0074032-g007: The perceived directions of the dual barber poles in which the duty cycle of the two component barber poles differed.A. Three example dual barber poles with the duty cycle of the left component barber pole 2/3 times (upper panel), equal (middle panel), or 3/2 times (lower panel) that of the right component barber pole (duty cycle = 50%). B–C. The probability of perceiving a global motion observed in an example subject (B) and in the mean across subjects (C). D–E. The perceptual bias observed in an example subject (D) and in the mean across subjects (E). *: p < 0.05 across conditions.

Mentions: We then varied the duty cycle in the left component barber pole while keeping the other parameters the same to test whether a difference in the duty cycle between the component barber poles affects the strength of cross-hemifield integration. The duty cycle of the left component barber pole was 33.3% (50% *2/3), 50%, or 75% (50% *3/2) and that of the right component barber pole was 50% (Figure 7A).


Global motion percept mediated through integration of barber poles presented in bilateral visual hemifields.

Huang LT, Wong AM, Chen CP, Chang WH, Cheng JW, Lin YR, Pei YC - PLoS ONE (2013)

The perceived directions of the dual barber poles in which the duty cycle of the two component barber poles differed.A. Three example dual barber poles with the duty cycle of the left component barber pole 2/3 times (upper panel), equal (middle panel), or 3/2 times (lower panel) that of the right component barber pole (duty cycle = 50%). B–C. The probability of perceiving a global motion observed in an example subject (B) and in the mean across subjects (C). D–E. The perceptual bias observed in an example subject (D) and in the mean across subjects (E). *: p < 0.05 across conditions.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756956&req=5

pone-0074032-g007: The perceived directions of the dual barber poles in which the duty cycle of the two component barber poles differed.A. Three example dual barber poles with the duty cycle of the left component barber pole 2/3 times (upper panel), equal (middle panel), or 3/2 times (lower panel) that of the right component barber pole (duty cycle = 50%). B–C. The probability of perceiving a global motion observed in an example subject (B) and in the mean across subjects (C). D–E. The perceptual bias observed in an example subject (D) and in the mean across subjects (E). *: p < 0.05 across conditions.
Mentions: We then varied the duty cycle in the left component barber pole while keeping the other parameters the same to test whether a difference in the duty cycle between the component barber poles affects the strength of cross-hemifield integration. The duty cycle of the left component barber pole was 33.3% (50% *2/3), 50%, or 75% (50% *3/2) and that of the right component barber pole was 50% (Figure 7A).

Bottom Line: Surprisingly, when the inter-component distance between the two apertures was short, the perceived direction of motion of the dual barber poles was similar to that of a single barber pole formed by the concatenation of the two component barber poles, indicating motion integration is achieved through a simple concatenation mechanism.We found that integration is achieved only when phase, speed, wavelength, temporal frequency, and duty cycle are identical in the two barber poles, but can remain robust when the contrast of the two component barber poles differs substantially.We concluded that a motion stimulus presented in bilateral hemifields tends to be integrated to yield a global percept with a substantial tolerance for spatial distance and contrast difference.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.

ABSTRACT
How is motion information that has been obtained through multiple viewing apertures integrated to form a global motion percept? We investigated the mechanisms of motion integration across apertures in two hemifields by presenting gratings through two rectangles (that form the dual barber poles) and recording the perceived direction of motion by human observers. To this end, we presented dual barber poles in conditions with various inter-component distances between the apertures and evaluated the degree to which the hemifield information was integrated by measuring the magnitude of the perceived barber pole illusion. Surprisingly, when the inter-component distance between the two apertures was short, the perceived direction of motion of the dual barber poles was similar to that of a single barber pole formed by the concatenation of the two component barber poles, indicating motion integration is achieved through a simple concatenation mechanism. We then presented dual barber poles in which the motion and contour properties of the two component barber poles differed to characterize the constraints underlying cross-hemifield integration. We found that integration is achieved only when phase, speed, wavelength, temporal frequency, and duty cycle are identical in the two barber poles, but can remain robust when the contrast of the two component barber poles differs substantially. We concluded that a motion stimulus presented in bilateral hemifields tends to be integrated to yield a global percept with a substantial tolerance for spatial distance and contrast difference.

Show MeSH
Related in: MedlinePlus