lecture 16: parietal lobes Flashcards
effects of damage to the parietal lobe
–> impairments in processing spatial information
- 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
effects of left parietal damage
- agraphia
- acalculia
- right/left confusion
- dyslexia
- difficulty in drawing (details)
agraphia
- problem in writing
- there is no impairment in the words being produced, the difficulty is organising it on the page (spatial problem)
acalculia
- difficulty with math
- issue with organising it in the proper spatial arrangement (not necessarily a problem with the actual math)
- just dont know where to put the numbers
difficulty in drawing (details)
- difficulty isn’t to do with the overall shape, the issue is the details
effects of right parietal damage
- difficulty in recognising unfamiliar views of objects
- difficulty in drawing (overall shape)
- contralateral neglect
difficulty in drawing (overall shape)
- details are there, but the overall shape isn’t quite right
contralateral neglect
- don’t recognise/see the left side, can’t look left or turn lect
eg: someone might only put lipstick on their right side - right parietal lobe damage neglect to the left
clinical tests to reveal contralateral neglect
- line cancellation and letter cancellation
result = they crossed all lines on the right and none on the left - line bisection
sticky attention
if their attention is kept on the right side by lots of info, they are less likely to move over to the left side
how to test if neglect is pre perceptual or post perceptual
- burning house anecdote
- milan piazza experiment
explain the debate between pre-perceptual or post-perceptual
- are they not seeing the left side (pre-perceptual) or are they seeing it but just not consciously aware/responding (post perceptual )
burning house anecdote
procedure:
* Neglect patients were shown two pictures of a house:
* One normal
* One with flames on the left side
* Patients said the houses looked the same — they were not consciously aware of the flames
But when asked:
“Which house would you rather live in?”
results:
→ They preferred the one without fire, even though they claimed they couldn’t see a difference.
* Suggests some implicit processing of the neglected side is happening, patients can see without conscious awareness
So neglect is likely post-perceptual - info is processed at some level but doesn’t reach conscious attention
milan piazza experiment
procedure:
* Patients with neglect were asked to imagine standing in Piazza del Duomo in Milan, facing one direction
* They described buildings only on the right side
* Then they were told to imagine facing the opposite direction
* Now, they described buildings they previously “ignored”
* And ignored buildings they had just described!
results:
* The neglect affects internal mental imagery, not just visual perception
- Again it points to post perceptual processing, the information exists in memory, but attention is biased
what are the two options for whats being neglected
- ego centered
vs - object centered neglect
ego centered
- impose vertical ego access on object
- dividing my visual world into a right side and a left side
- neglect is based on the persons own point of view
- the patient ignores the left side of their body space, relative to their own midline
object-centered neglect
- ignore the left side of the object irrespective to if the object falls to my left or right
- neglect is in relation to objects, not the self
- the patient ignores the left side of individual objects, regardless of where they are in space
