3. The visual system III Flashcards
(17 cards)
What surrounds the fovea and is characterized by a pattern of small capillaries?
The macula
The macula plays a crucial role in central vision and color perception.
Where is high-frequency small cones concentrated?
The fovea
The fovea is essential for sharp central vision.
What condition affects the area surrounding the fovea, leading to central vision loss?
Macular degeneration
This condition is a leading cause of vision impairment in older adults.
What did Hubel and Wiesel’s experiments demonstrate about visual cortex neurons?
They respond to specific stimulus orientations
Their research was pivotal in understanding visual processing.
How is the visual cortex organized?
In columns where neurons within a vertical column respond to the same stimulus orientation
This organization facilitates efficient visual processing.
What happens when moving horizontally across columns in the visual cortex?
It reveals neurons that respond to gradually changing stimulus orientations
This allows the brain to interpret complex visual information.
What is the significance of the visual cortex’s organization?
It allows for pattern recognition
Images can be decomposed into elements with different orientations.
What are ocular dominance columns?
They represent input from left and right eyes
These columns are essential for binocular vision.
What can alter the representations in ocular dominance columns?
Monocular deprivation during critical developmental periods
This can lead to visual impairments if not corrected.
Which layer of the visual cortex shows clear alternation between left and right eye representation?
Layer 4
This layer is crucial for processing inputs from both eyes.
What is found outside Layer 4 of the visual cortex?
More blending of input from both eyes, creating binocular vision areas
This blending enables depth perception.
What are the two main categories of eye movements?
Gaze-shifting movements and gaze-stabilizing movements
Each category serves different functions in visual tracking and stability.
What are saccades?
Rapid ballistic movements that quickly change fixation direction
These movements are often reflexive and occur during reading.
What are smooth pursuits?
Slower tracking movements that follow moving objects
These movements are voluntary and help maintain focus on moving targets.
What is vergence?
Coordinated movement of both eyes relative to each other for focusing on near objects
This is essential for maintaining single vision at close distances.
What does the vestibulo-ocular reflex do?
Compensates for head movements based on vestibular system input
This reflex helps keep the visual field stable.
What is the optokinetic response?
Reflexive eye movements in response to repetitive visual motion across the field of view
This response helps track moving scenes.
