Lecture 16 - Parietal lobes Flashcards
Effects of damage in parietal lobe is
dependent on where the damage is
Effects of damage on the parietal lobe causes impairments in
Impairments in integrating sensory information
Impairments in the control of movement
Impairments in guiding movements to points in space
Impairments in abstract concepts
Impairments in directing attention
Impairments in Processing Spatial Information
Effects of left parietal damage
Agraphia - difficulty writing, difficulty organising words on a page (organising the letters into words), spatial context hard
Acalculia - problem with organising the information in the right space, loss of ability to perform simple calculations
Agraphia
Agraphia - difficulty writing, difficulty organising words on a page (organising the letters into words), spatial context hard
Acalculia
Acalculia - problem with organising the information in the right space, loss of ability to perform simple calculations
Left parietal lobe lesion causes
spacial problems
Right and left confusion
Dyslexia
Difficulty in drawing (details)
These abstract abilities are rooted in spacial processing problems
Effects of right parietal damage (lesions)
Difficulty in recognising unfamiliar views of objects i.e. side on view vs birds eye view of an object
Difficulty in drawing (overall shape)
Contralateral neglect
Contralateral neglect
right sided lesions therefore neglect of the left (in right handed people) - most common
Relates to handedness (left handed people, left lesions, neglect of the right)
Any other combination does not work
Loses the regard of the left, cannot bring it to their attention and they have no conception that they are wrong, can’t look or turn left
Look at everything or read everything to the right of an object
Clinical tests for contralateral neglect
Line cancellation and letter cancellation
Line cancellation - cross off all lines on a piece of paper and what they do is cross all the ones on the right and leave all the ones on the left because they do not see them
Letter cancellation - for example they are asked to circle all the As written down on a piece of paper, end up only circling the right side, however people with an incentive/motivational component or attention component circle more letters
Line bisection
Draw a line that separates it at the halfway point
The big question about contralateral neglect
Is neglect a perceptual problem or a post perceptual problem?
Is it a problem with seeing it or are you seeing it but having trouble with interacting with the left side? - evidence seems to suggest that all the information is getting into the brain properly but there is a problem interacting with the information
Information on the right side becomes overwhelmingly attention gripping to the exclusion of information on the left hand side
Is neglect a perceptual problem or a post perceptual problem? - Burning house anecdote
Burning house anecdote
Not a rigid scientific experiment
Flames out of left window in one house and the participants will say it is fine due to contralateral neglect and then they are also shown a house with no flames, when they are asked which one they would want to live in they choose the one with no flames so somehow they register there is a fire in one house but do not see it in their visual field
Is neglect a perceptual problem or a post perceptual problem? - Milan piazza experiment
Milan piazza experiment
People that live there know all the shops
Shows contralateral neglect
Look at the town square at two different orientations and record all the information but it is interacting with the information that is the struggle (post perceptual problem)
What is being neglected in contralateral neglect?
- Ego-centered neglect (own body axis - ignore left side) 2. Object-centered neglect (object axis - ignore left side even if in the right side view)
Ego-centered vs object centered neglect
Evidence for both, 2 opposing views
Object centered - ignoring the left side of an object irrespective of where it appears to you
Right halves draw tell us that we are dealing more with object centred neglect - hard to untangle them as they could be focusing on one with its ego axis and then the other so egocentered
Driver, Baylis, Goodrich, and Rafal (1994)
Asks you whether triangle is point at 2,6 or 10 o’clock
For image, the first triangle people say all three times (even spread) where as the second lot of triangles the majority say that the triangle is pointing to 10 o’clock
Driver, Baylis, Goodrich, and Rafal (1994)
Asks you whether triangle is point at 2,6 or 10 o’clock
For image, the first triangle people say all three times (even spread) where as the second lot of triangles the majority say that the triangle is pointing to 10 o’clock due to their layout
shows that neglect has an object based component
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