L9- attention & parietal lobes

Question 1

what is attention

Answer 1

mind in clear and vivid form
- alertness
vigilance
selective attention
cocktail party effect
effort & resource capacity - mental workload & task difficulty
- sensory specic processes?

Question 2

component processes by discrete brain areas - see what’s happening in hemineglect

Answer 2

Posner’s attention switching paradigm
- covert attention
fixate, box flashed, then, cue on of of two targets either same side or different than box flashed, push button on side of target.
match = congruent
primed to respond to congruent. longer to respond to incongruent becauase have to disengage attention and reengage elsewhere.

Question 3

what brain areas are important for disengaging, moving, re-engaging

Answer 3

parietal cortex, superior colliculus, thalamus.

Question 4

recruitment of DLPFC - when?

Answer 4

divided attention.
doesnt activate for uni stimulation. just bi-stimulation.
working memory task.

Question 5

posterior parietal lobe damage - symptoms

Answer 5

contralateral neglect - lesion usually in right inferior PL - right intraparietal sulcus & right angular gyrus

• unaware of lest side of space
• caused by defective sensation/perception? or defective attention/orientation?

Question 6

hemineglect

- note the features

Answer 6

contralateral.
body midline - neglect begins dead centre
multisensory - altiudinal neglect, depth neglect.
somatopharaphrenia - think body doesnt belong - low self awareness

extinction - clinical sign of hemineglect = double simultaneous sitmuli, fail to detect contralesional stimulus when other stimulus present on ipsilesional side.

Question 7

extinction - attention related?

- some tests

Answer 7

line bisection test - dont biset halfway.
drawing attention to left sign improves spatial cue.
seeing antiballistic - say ballistic bc brain splits words but has to make sense.

Question 8

bisiach & luzzatti

Answer 8

tested neglet patients. 70’s, in hospital, spent life in milan. asked to imagine standing in plaza, looking at cathedral, name iconic features.
- neglect to left side, 100% correct on right side.
next, switched sides. image standing on cathedral steps. previous left side/now right = seen, previous right not seen.
- imagined neglect, not just visual *attention and memory closely linked, not externally driven&

Question 9

extinction within peripersonal space

• brain areas coding for visual space
• how do cells respond to visual stimuli

Answer 9

• • parietal lobe, frontal cortex, putamen.
• visual stimuli in close proximity of body party = fires.
  bimodal - usually repond to tactile & visual.
  receptive field matches btw visual and tactile on body surface.
  = brain regions part of system for integrated coding for peripersonal space.

Question 10

study 1 for peripersonal space

Answer 10

• right parietal damage patients; left tactile extinction.
• unimodal - felt left hand. bimodal: felt only ipsilesional hand. tactile stimulus near right hand, didnt feel left hand.
• same thing works for visual stimulus near hand; too far from hand = no extinction
• • mechanism: visual stimulus near ipsilesional body part activates somatosensory representations to that body.

Question 11

study 2 - exist in other body parts?

Answer 11

on face - add blinder/eyepatch

dont feel if visuotactile is near. do feel if visuotactile is far.

Question 12

study 3 - vision of hand input in peripersonal space

Answer 12

rubber hand - same results when in correct orientation. illusion

Question 13

s4: peripersonal space modified w tool,

Answer 13

tool in hand - felt left hand.
using tool change receptive field of neurons = left hand not felt.
- extension of arm as pointing to match length of tool = no extinction.
effect only lasted a few minutes.
dynamic property

Question 14

prism effect in neglect patients

Answer 14

prism goggles shift gaze to left side of space.

• more extension to left side after removing prisms. best effect = 2 hours after taking off prisms. - make person aware of left side.
• interplay between remembering and seeing. remembering they saw more, so they attend to it and see

Question 15

balint’s syndrome

• triad of symptom
• damage?

Answer 15

• visual perception (simultaneous agnosia)
• optic ataxia (no visually-guided reaching)
• psychic paralysis (oculomotor apraxia - difficulty directing saccades, difficulty breaking fixation.

damage: posterior parietal cortex. - widespread, bilateral

Question 16

case of JG

what can we learn from JG

Answer 16

• 3YOA, had meningitis, needed some of parietal lobes removed.
  -10YOA delayed development. hard to read, couldnt track objects.
  *treatment = adaptive approach. took note of strengths and abilites to rehabilitate. = scan ground, keep enviro uncluttered, reading techniques.
  11 YOA - optic ataxia, oculomotor apraxia persisted = learnt to cope and naviggate.

LEARN: balints in children, vary in symptoms, vision for action = dorsal.