Trivia Facts and Questions on Mechanisms of Visual Attention! There is a way in which the human mind or eye can focus on an object and see if better than other people. Do you know some of the studies undertook to measure how someone is attentive when it comes to vision? Take this test and show off what you know.
Orientation - directing your attention to a point of interest
Sorting - Limiting the number of distractors you pay attention to
Selection - Choosing what to pay attention to
Sustaining - Ability to repeat the attention task
Symbol digit modality
Test of Silent Word Reading
Rapid serial visual presentation (RSVP)
Trail making test
Younger children showed the most improvement after playing the first person shooter games, thus allowing them to conclude that attention was learned at an early age
The found that non-video gamers who played first person shooter games improved and concluded that attention mechanisms have plasticity to them and therefore can be altered or improved
There was no difference in the attentional mechanism between the video gamers and the non-video gamers.
Attentional blinking increased in non-video gamers while it stayed stagnant in the seasoned video gamers.
Visual attention refers to how much visual information we process
Paying close attention to one task results in loss of attention to other tasks
Visual search procedures are a clinical assessment of visual attention in which you must find a target among certain distractors.
All of the above are true
Difficulty perceiving & responding to a 2nd target amid a rapid stream of targets
Observers tend not to notice that a letter or word they are looking for has been repeated
In normal corresponding system the objective angle and subjective angle are going to be equal.
Point zero will be where the fixated target falls on the retina of the deviated eye.
Correspondence is a retinal phenomenon
There are two ways to measure the angle of anomaly: directly using afterimages or by measuring the objective angle and subtracting it from the subjective angle
The condition in which two foveas and other homologous retinal loci do not correspond to each other in regard to visual direction.
The locus of all points in visual space that are imaged on corresponding points in each eye when the eyes are converged at fixed location
When two targets (one presented to each eye) are perceived as lying in the same visual direction
Points in space seen as equidistant will not stimulate motor fusion.
The patient is capable of making large fusional vergence movements to prism
Unharmonious anomalous correspondence means the angel of anomaly has not shifted all the way to that zero point. It’s somewhere b/t the fovea and that zero point. So you can think of it as an incomplete adaptation.
It allows a rudimentary form of binocular coordination
In unharmonious AC the angle of the anomaly and the objective angle are equal.
The foveas were never connected even in a normal corresponding system
The are intermittently connected in an anomalous corresponding system
The foveas are no longer hooked up in an anomalous corresponding system
The foveas begin connected at the beginning of the day but with prolonged use they become disconnected in an anomalous corresponding system
Patient will perceive vertical after image, which is going to project out nasally (to the right). And the horizontal line will be here (to the left of the vertical line).
Patient will perceive vertical after image, which is going to project out temporal (to the left). And the horizontal line will be to the right of the vertical line.
The patient will perceive a perfectly aligned cross
The patient will perceive the vertical line displaced superior compared to the horizontal line
Adaptation happened during the critical period where there was a lot of plasticity in the neurological system and so it would make sense for the system to develop a mechanism to deal with the diplopia and confusion that would come about from strabismus.
As proof for the Sensory theory Burian used strabismic patients that have early onset strabismus who developed AC. If you have an older pt with 6th nerve anomaly they don’t get AC. But if you have a pt with early strab onset (in first 2 years of life) during the critical period they tended to develop AC.
The sensory theory not only successfully explains confusion and diplopia but it also explains co-variation and therefore it is the prevailing explanation for AC
In a normal corresponding system the fovea would go through where the visual axis would cross.
Flom found that esotropes with AC had a fairly typical horopter curve shape in the periphery, as it approached the fovea the horopter started to change and switch over to a normal corresponding system
Flom hypothesized that the horopter notch could prevent the patient from fusing the targets because it creates a large skew in the horopter like the geometric effect.
Flom tested esotrope with normal correspondence they have a curve with a negative H value so it’s inside the V-M circle.
6 to 12 minutes of arc
Occurs as a result of Panum’s fusional area
Most intense at fovea and zero measure point
Depends of type of stimulus, larger for lower spatial frequencies.
Go from a steeper curve to a flatter curve
Go from a flatter curve to a steeper curve
They are a measure of vergence adaptation
The shape of the horopter and the deviation from the VM circle
The associated phoria
The amount of suppression that takes place in a stabismic patient
Here's an interesting quiz for you.