Block 12 Flashcards
Inability to recognize faces
Prosopagnosia
- dorsal processing
- parietal path
- where path
They scribe the visual path that processes what
Process motion
Optic ataxia may result from damage in which cortical processing stream
Dorsal-dorsal
Inability to point or reach for a target
Optic ataxia
Form of attention that alerts you when another vehicle swerves into your lane
Bottom up
Form of attention from an external source
Bottom up
Observer controls what they are attending to
Top down
Clinical condition that may be caused by abnormal connections between cortical modules
Synaesthesia
Damage to inferotemporal cortex may result in deficits in analyzing what
Form
Akinetopsia may result from damage to
Area v5
As the number of distractions increases, the ability to detect the salient objects
Remains the same
Shifts in attention alter the responses of cells located where
Area v4
Type of attention: looking for a friend in a crowd of people
Top down
Type of attention: responding to the slamming of the door
Bottom up
Type of attention: searching for quarters in a drawer of loose change
Top down
Prosopagnosia is most likely to be accompanied by
Achromatopsia
Cortical areas that are a part of the ventral processing system
IT and V4
Inability to perceive 2 objects simultaneously
Simultagnosia
Visual hallucinations experienced in Charles bonnet syndrome have been compared to
Phantom limb syndrome
- Demonstrated in elderly people
- used to treat amblyopia
Perceptual learning
How many areas of the brain are distinct visual areas
20
Each visual area has what
A retinotopic map
Are the processing streams independent of each other
No
Which stream is critical for identifying and recognizing objects
Temporal, ventral, what stream
Which stream plays a role in motion perception, localization in visual space, and action organization
Dorsal, parietal, where stream
2 parts of the dorsal stream
Dorsal-dorsal stream
Ventral-dorsal stream
Which arm of the dorsal stream processes action info
Dorsal-dorsal stream
Damage to the dorsal-dorsal stream may result in
Optic ataxia
Inability to point to or reach for a visual target
Optic ataxia
Which arm of the dorsal stream includes extrastriate area MT/V5
Ventral-dorsal
Which arm of the dorsal stream plays a role in space perception and action organization
Ventral-dorsal
The parvo path has strong input to
Ventral stream
Mango path inputs mainly to which stream
Dorsal stream
Which retinogeniculate pathways may provide input to
Both corical processing streams
Area that has an abundance of cells with chromatic sensitivities
V4
Cells in which area respond to complex forms, including faces
IT
This area is well adapted to color perception
V4
The area plays a role in form perception
IT
V4 and IT are part of which stream
Ventral
Areas MT/V5 are a part of which stream
Dorsal
Which imaging technique has better resolution: fMRI or PET
fMRI
Which imaging technique uses a radioactive tracer to observe changes in blood flow indicating increased cortical metabolism
PET
Which imaging technique reveals cortical activity by detecting levels of oxygenation (BOLD- blood oxygen level dependent)
fMRI
If asked to view a certain color, but stream may have elevated activity
Ventral
If asked to focus on the shape or form of an object, which stream becomes active
Ventral
If asked to focus on the movement of on object, which stream will have increased activity
Dorsal
Motion and position are processed along
Dorsal
Color and form info are processed along
Ventral
Integration of the info from dorsal and ventral with memory is coordinated by
Prefrontal cortex
Area been though to play a role in cognition
Prefrontal cortex
Cells in the MT/V5 are capable of analyzing
Motion info
The movement of a plaid pattern (an integrated stimulus of 2 components) appears as a
Single object moving in an intermediate direction by area MT/V5
What area has also been studied with random dot kinematograms
MT/V5
MT/V5 is more active when viewing what kind of object
Moving object
A motion illusion that occurs in the absence of motion
MAE (motion aftereffect)
Motion detectors mediating the MAE are located
In the cortex
Where it’s he first site of substantial interaction between the2 eyes
Cortex
Size of receptive fields of cells in IT
Large
Cells in IT respond best to
Sophisticated shapes
Which cells respond best to bars, edges and gratings
Cells in the striate cortex
Area of the brain that responds well to objects, but not scrambled objects or object fragments
LOC (lateral occipital complex)
What area of the brain responds well to faces, but not other objects
FFA (fusiform face area)
Which area of the brain is strongly activated by objects and places, but not faces
PPA (parahippocampal place area)
What cortical area processes:
1- face
2- color
And are in close proximity
1- FFA
2-V4
Pts who suffer from prosopagnosia may also manifest what (because of location of brain areas)
Cerebral achromatopsia
This form of attention is volitional
Top down
Directing our attention on each object of interest to see what is available is an example of
Serial processing
What type of processing facilitates detection of the salient feature
Preattentive processing
Phenomenon in which we cannot readily see the difference between 2 images
Change blindness
What condition can make changes between 2 images more visible
- presented in rapid sequence (triggers our exogenous attention)
What condition can make changes between 2 images less visible
2 images presented simultaneously (dont as readily elicit our attention)
Which area of the brain is involved in topdown visual attention
Prefrontal cortex
Do cells in the striate cortex demonstrate topdown attention
No
Lesions in the striate cortex produce
Simple blind spots (scotomas)
Extrastriate lesions can lead to
Visual agnosia
Defect in the perception of motion
Akinetopsia
Where is the damage in akinetopsia
Dorsal processing stream
Lesions to the superior temporal lobe can lead to
Visual neglect (only recognize one side - only eat one half of plate, only shave one side of face, etc)
Not able to percieved more than one object at a time
Simultagnosia
Simultagnosia may be seen in pts with what syndrome
Balint’s syndrome
Condition where there is bilateral damage to parietal lobes
Balint’s syndrome
The presentation of a letter or number results in the perception of a color
A form of synesthesia
Is it uncommon for patients with visual loss to experience visual hallucination (phantom vision)
No, it is common
Complex visual hallucinations that often take the form of a person, but are recognized as the patient as not being real, occur in what syndrome
Charles bonnet syndrome
Area of the brain that plays a big role in encoding memories
Hippocampus
Is there evidence that neurons with highly specialized receptive fields may play a role in encoding memories
Yes
Perceptual learning has been used to improve what 2 things
- visual function in amblyopia
- near VA in children with low vision
The cortex manifests a significant degree of what
Specialization
Brain areas involved in ventral processing stream
V4 and IT
Brain areas involved in dorsal stream
MT/V5
What part of the brain may coordinate integration of info from the 2 systems
Prefrontal cortex
Neurons in what part of the brain correspond closely with our perceptions and playa role in perceptual learning, striate cortex or higher visual centers?
Higher visual centers
What picture can be used to possibly train vision
Necker cube
Stimulus for: EOG
Adaptation
Stimulus for: ffERG(flash)
Ganzfield flash
Stimulus for: ffERG(flicker)
Ganzfield flash
Stimulus for: pERG
Pattern reversal
Stimulus for: mfERG
Multifocal flash pattern
Stimulus for: VEP
Pattern reversal
Stimulus for: mfVEP
Multifocal pattern reversal
Magnitude of: EOG
6 mV
Magnitude of: ffERG (flash)
1 mV
Magnitude of: ffERG (flicker)
1 mV
Magnitude of: pERG
5 microV
Magnitude of: mfERG
1 microV
Magnitude of: VEP
5 microV
