Term
| What is the independent stimulus presented to each eye alone? |
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Definition
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Term
| What results when dissimilar objects are formed on corresponding points. |
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Definition
| Binocular confusion. Two different objects are perceived as occupying the same position in visual space. |
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Term
Does suppression occur instantly once diplopia and confusion are present? |
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Definition
| No, it may take between 75 to 150 ms |
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Term
Can a monocular patient suppress? |
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Definition
| No, while suppression is monocular, it arises due to binocular interactions. |
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Term
| What is the normal and beneficial type of suppression called? |
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Definition
| Physiologic suppression, to distinguish it from pathological or binocular suppression. |
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Term
| Can strabismics consciously control which eye is dominant? |
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Definition
| Yes, although they are often unaware of a switch in eye dominance |
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Term
| What do you call suppression triggered by dissimlar binocular inputs? |
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Definition
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Term
| What type of binocular rivalry occurs when the entire image of a target is alternately suppressed and when does it occur? |
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Definition
| Exclusive dominance, it occurs with targets that are smaller in area |
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Term
| What type of binocular rivalry results in a patchwork of contours continuously changing over time? With what type of objects does this occur? |
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Definition
| mosaic dominance; It occurs with larger targets |
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Term
| How big are the spatial zones of binocular rivalry in a case of mosaic dominance? |
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Definition
| The size of a hypercolumn |
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Term
| Which spatial zone of binocular rivalry is bigger, nasal or peripheral? |
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Definition
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Term
| How are suppression and binocular rivalry similar? |
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Definition
1) Both remove portions of the visual field from suppression
2) Similar types of dominant visual stimuli
3) The degree of threshold elevation can vary in strength as a funciton of stimulus characteristics |
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Term
| How are suppression and binocular rivalry different? |
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Definition
VIDS
1) In bioncoular rivalry, the rate of change of the visibility of targets in each eye is not under voluntary control.
2) In bincoular rivalry, although it is not consciously perceived, the region of an image that is momentarily suppressed during binocular rivalry maintains an influence over the visual system.
3)Binocular suppression requires different stimuli to each eye, while pathological suppression can occur with similar images in each eye.
4)Strength, the suppression in binocular rivalry tends to be stronger than it is in suppression |
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Term
| How long does pathological suppression take? |
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Definition
| 1 to 2 minutes, much longer than the 200ms required by physiological suppression |
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Term
| What is the DaVinci effect? |
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Definition
| Binocular rivalry that occurs under normal viewing conditions. This can happen when a distant object is completely occluded in one and and only partially occulded in the second eye by a near object. |
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Term
What is it called when a distant object partially occludes a far object, creates a rivalrous percept, and the rivlarous percept is beneficial? |
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Definition
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Term
| Is saccadic suppresion a form of binocular rivalry? |
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Definition
| No, saccadic suppression is a monocular form of suppression. It has a different mechanism. |
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Term
Is dichoptic masking a form of binocular rivalry? |
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Definition
| No, the behavior of binocular rivalry is different from that of dichoptic masking. |
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Term
| What is the zone of suppression due to? |
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Definition
| The inhibitory effect of the surround region of the center surround receptive fields excited by the contour. |
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Term
| What happens when you have different objects of similar shape and orientation but differ greatly in color, luminance, or have opposite contrast signs? |
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Definition
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Term
| What does the patient see in an anaglyphic presentation if he is fusing the images? What if he suppresses? |
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Definition
| If the patient fuses the images, he will see luster between the red and green images if he exhibits binocular fusion. He will see no luster if he is suppressing. |
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Term
| Does binocular rivalry preclude steropsis? |
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Definition
Binocular rivalry can interfere with stereopsis but some stereopsis is still present. |
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Term
| What suggests that binocular rivalry and steropsis are mediated by independent mechanisms? |
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Definition
| The fact that stereopsis is still perceived during binocular rivalry but is somewhat lessened by binocular rivalry. |
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Term
| What suggests that binocular rivalry is after the site of spatial frequency processing? |
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Definition
| Aftereffects such as spatial frequency and tilt aftereffects are not adversely effect when the adapted stimulus is suppressed in a rivalrous presentation. |
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Term
| What suggests that binocular rivalry and suppression must be attributed at least in part to cortical processing? |
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Definition
| Since the aftereffects are generated when rivalrous stimuli are presented, we know that the aftereffect and hence binocular rivalry and suppression must be at least partly due to cortical processing. |
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Term
How is the concept that a sharp image in one eye will suppress a blurry image in the fellow eye? |
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Definition
| Monovision contact lenses |
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Term
| Why are esotropes more likely than exotropes to develop amblyopia? |
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Definition
In an esotrope, the image formed on the fovea of one eye is rivaled against and image formed on the nasal retina of the fellow eye. In exotropes the image formed on the fovea of one eye is rivaled against an image formed on the temporal retina of the fellow eye.
Hence the esotrope fellow eye gives a stronger response because its nasal, creating a need for suppression. A temporal image in the fellow eye isn't strong enough to require suppression |
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Term
| What suggests that rivalry is not a simultaneous precept but takes time to occur? |
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Definition
| Brief presentations of rivalrous stimuli are often seen as simultaneous perception of two monocular images despite their dissimilarity. |
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Term
| What are you measuring when you find the point where a rivalrous stimulus changes from an alternation of stimuli as a whole to a piecemeal alternation in different regions of the visual stimulus? |
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Definition
| The spatial zone of suppression, which is also dependent on the size of the receptive fields. |
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Term
| Why is binocular rivalry thought to occur relatively high in the visual system? |
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Definition
Adaptation can occur due to a suppressed stimulus during rivalry even the stimulus is not seen. Adaptation effects are cortical. Therefore rivalry must take place at stages beyond those at which rivalry occurs. |
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