Chapter 10 Pt.2 Flashcards
Amedi and coworkers
- Deactivation of non-visual areas of the brain (hearing, touch)
- mental images are more fragile, less activation keeps other things from interfering
Amedi and coworkers experimental design and results
- visual imagery
- scrambled imagery
- visual objects
A1: auditory area, temporal lobe (produces de activation for visual imagery)
V1: back of brain shows that perception is stronger than visual imagery at back of brain
Johnson-Johnson multi voxel analysis
Training: classifying voxel patterns to images that participants look at (perception): 63%
Test: ask participants to visualize image. Classifier uses exact same algorithm developed in training. Computer is able to classify the image with accuracy of 55%
Suggests that imagery voxel pattern is similar to perception
Kosslyn and coworkers experiment with TMS
TMS was presented to visual cortex and another cortex during perception and imagery
Perception task: out of these four images with lines, which is the longest
Imagery task: give them picture then take away and ask them to imagine it and determine which was longer
Result time slower for both when TMS applied. Suggests that brain activity in visual area of brain plays a causal role for both perception and imagery
What result supports the idea that visual cortex is important for imagery
- removing part of the visual cortex (occipital area) reduced the size of field of view
- decreases walking distance to image in mental walk task (longer distance to image)
Went from 15 feet to 35 feet
Unilateral (spatial) neglect
Patient ignores objects in one half of visual field in perception and imagery
Usually damage to parietal area (can’t see left part-think map)
Guariglia and coworkers
Found that frontal lobe damage left patients perceptions in tact but mental images were not
R.M.
- damage to occipital and parietal lobes
- could draw accurate pictures of objects in front of him (perception)
- could not draw accurate pictures of objects from memory (using imagery) and could not answer questions based on imagery
C.K. (Visual agnosia)
- can’t name objects in pictures, even from his own drawings
- could draw objects in great detail from memory (using imagery) if the names were given verbally
- could compare sizes and describe colours of objects (letter H experiment)
What do the results for neuropsychological studies suggest
Shows a Double dissociation between perception and imagery
Indicates separate mechanisms, also evidence though for shared mechanisms
Behrmann and coworkers
- mechanisms partially overlap
- visual perception is bottom up process (located at lower and higher visual centres)
- visual imagery is top down process (located at higher visual centres)
Explains C.K. And R.M. But not M.G.S (mental walk)
Differences in experience
Perception is automatic and stable
Imagery takes effort and is fragile
Chalmers and Resiberg (bunny/duck)
- had participants create mental image of ambiguous figures
- difficult to flip from one perception to another while holding mental image of it (duck/bunny)
Imagery to improve memory
- Method of loci
2. Pegword technique (rhyming, association and vivid image)
Coglab: Link word method
-interactive imagery between two concepts causes one item to become an excellent cue for retrieving the second item (need to study image for 10 seconds)
Think goat on chevy
The French word served as a good cue for the image and the image serves as a link to the English meaning
Individual differences in visual imagery
Spatial imagery people are better at mental rotation (paper folding and then pierce hole through it)
Object imagery people better in degraded picture task
VVIQ
Vividness of visual imagery questionnaire
Compared people with low spatial imagery to those with high. People with low spatial imagery did better on VVIQ task then those with high
