Attention and Parietal Lobes Flashcards
Who said? “everyone knows what attention is. It is the taking possession by the mind in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought… it implies withdrawal from some things in order to deal effectively with others”
William james in 1890 in his book “Principles of Psychology”
What are 6 sections of Attention?
- alertness and arousal
- vigilance
- selective attention (withdrawal block other information around you)
- Orienting –> cocktail party
- effort and resource capacity –> mental workload and task difficulty –> resource capacity is our attentional system being limited
- sensory specific processes like visual attention, tactile attention, auditory attention are multimodal and apply to all of our senses
What is Posner’s Attention Switching Paradigm?
looks at covert attention (shifting attention without moving eyes)
- subject looks at cross on the screen with two boxes to the right and left side, one box on one side flashes
- then the subject is shown two different scenarios where theres an astirx on the side that flashed and another scene where an astix is on the side that didn’t flash
- showed that it takes longer to respond in the invalid condition (the astreik that appears on the opposite side of the original flash)
the valid cue in this case was the one that matched with the initial cue and the invalid cue was the one that didn’t match
How is the recruitment of the DLPFC (dorsolateral prefrontal cortex) involved in divided attention?
superior aspects of the DLPFC get engaged when you shift your attention between 2 modalities i.e. visual and auditory but not separately
the experiment showed that DPLFC fired when there was bimodal divided attention (i.e. the person was trynna pay attention to auditory and visual stimulus) but not firing for only aud and only visual
What is contralateral neglect? Where does the lesion need to occur?
- lesion is most often in the right inferior parietal lobe
- or the right intraparietal sulcus and the right angular gyrus
- noted after lesions to the frontal lobe and cingulate cortex
- defective sensation or perception
- defective attention or orientation
what is heminglect?
heme-inattention
- not paying attention to one side of space
- contralateral to the area of the lesion
- occurs at the body midline outwards
- multi sensory –> affects all sensory modalities
- somatoparaphrenia: feels like some of their body parts in the left side are not there
- double simultaneous stimulation technique (extinction)
What is extinction?
clinical sign of hemineglect
- patients detect a single stimulus, either episilesional (same side as their lesion) or contralesional (opposite side of their lesion) of the body
- they fail to detect the contralesional stimulus when a concurrent stimulus is presented on the ipsilesional side
i.e if the lesion is on the right hemisphere, then they can’t see whats in the left visual field when another stimulus is presented in their right visual field
what is the line bisection task? what does it indicate about hemineglect?
asking them to draw a vertical line where they would think the middle of a horizontal line would be
- performance improves with spatial cues
What is significant about showing the word “antiballistic” to an individual with hemineglect and the line bisection task?
the line bisection task indicates which area of the word they will see and which ones they won’t, according to the line bisection, they will only see the word “listic” but they will interestingly say “ballistic” because they will incorporate experience into semantic meaning of the word
What was Bisiach and Luzzatti’s experiment on hemineglect patients?
- experiment seeing if memory is affected by the neglect of the patient
- Working with left neglect patients with right parietal lesions from roughly the same small town
- showing them a picture of the small town and asking them in one scenario to picture themselves standing at an “x” landmark and describing all the landmarks they see around them from memory
- and then another task: asking them to stand from a different “x” landmark, and asking them to describe landmarks around them from memory
- results showed that during the first task, the patients only recalled the landmarks to the right of them (in their memory) very clearly but only recalled a few to none of the left side
- when placed in the other landmark in the second task, they could name only the left side landmarks and not the right side
- this shows that depending on where they visualize themselves being in their memory, their left side of their visual field is always impaired but if you put together the two tasks, they clearly remember each area clearly
What were 5 conclusions of the Bisiach and Luzzatti’s experiment?
- memory is intact
- left side neglect
- not externally driven
- attention and memory are intimately linked
- attention may be required to recall things (i.e. spatial memory tasks)
What is peripersonal versus extra personal space?
peripersonal space is space close to our body
extra personal space is space not close to our body
what are three indications of peripersonal space?
when objects are in our peripersonal space it shows intimacy, threat and ownership
what do neurophysiological studies show of the brain areas specialized for coding of visual space surrounding the body?
- cells in the parietal and frontal cortices as well as the putamen respond to visual stimuli in spatial proximity to a particular body part like hand or face
- these areas are bimodal and respond to visual and tactile stimuli
- receptive fields for visual stimuli match those for tactile on body surface even when limb and eyes move away form the area of the body
What does peripersonal space in different brain regions suggest?
suggests that these brain regions are part of an interconnected system for integrated coding of peripersonal space entered on body parts
