Lecture 8: Parietal Lobes & Attention

Question 1

Posterior Parietal Cortex

Answer 1

parietal areas PE, PF, and PG lying posterior to the primary somatosensory areas

Question 2

Saccade

Answer 2

a series of involuntary, abrupt, and rapid small movements or jerks of both eyes

Question 3

Sensorimotor Transformation

Answer 3

neural calculations that integrate the movements of different body parts (eyes, body, arm, etc.) with the sensory feedback of what movements are actually being made and the plans to make the movements

depends on both movement-related and sensory-related signals produced by cells in the posterior parietal cortex

Question 4

Acalculia

Answer 4

inability to perform mathematical operations

Question 5

Stereognosis

Answer 5

tactile perception

recognition of objects through the sense of touch

Question 6

Afferent Paresis

Answer 6

loss of kinesthetic feedback that results from lesions to the postcentral gyrus (areas 3-1-2) and produces clumsy movements

Question 7

Astereognosis

Answer 7

inability to recognize the nature of an object by touch

Question 8

Simultaneous Extinction

Answer 8

the somatoperceptual disorder most commonly associated with damage to the secondary somatic cortex (areas PE and PF), especially in the right parietal lobe

two stimuli would be reported if applied singly, but only one would be reported if both were applied together

the second stage of recovery from contralateral neglect characterized by response to stimuli on the neglected side as if there were a simultaneous stimulation on the contralateral side

Question 9

Numb Touch

Answer 9

a tactile analogue of blindsight, in which individuals have lost tactile perception but are able to locate objects through touch

Question 10

Asomatognosia

Answer 10

loss of knowledge or sensory awareness of one’s own body and bodily condition

may be on one or both sides of the body

most commonly results from damage to the right parietal lobe

Question 11

Anosognosia

Answer 11

loss of ability to recognize or to acknowledge an illness or bodily defect

usually associated with right parietal lesions

Question 12

Anosodiaphoria

Answer 12

indifference to illness

Question 13

Autopagnosia

Answer 13

inability to localize and name one’s own body

Question 14

Asymbolia for Pain

Answer 14

inability to understand the meaning of or react to pain

Question 15

Contralateral Neglect

Answer 15

neglect of part of the body or space contralateral to a lesion

Question 16

Allesthesia

Answer 16

a stage of recovery from contralateral neglect characterized by a person’s beginning to respond to stimuli on the neglected side as if the stimuli were on the unlesioned side

Question 17

Agraphia

Answer 17

decline in or loss of the ability to write

Question 18

Apraxia

Answer 18

the inability, in the absence of paralysis or other motor or sensory impairment, to make or copy voluntary movements, especially an inability to make proper use of an object

Question 19

Ideomotor Apraxia

Answer 19

an inability to use and understand nonverbal communication such as gesture and pantomime or to copy movement sequences

Question 20

Constructional Apraxia

Answer 20

a visuomotor disorder in which spatial organization is disturbed

Question 21

Disengagement

Answer 21

the process by which attention is shifted from one stimulus to another

Question 22

Attention

Answer 22

a selective narrowing or focusing of awareness to part of the sensory environment or to a class of stimuli

Question 23

Conjunction Speech

Answer 23

a concept in attentional theory that assumes the existence of a mechanism with which the sensory system searches for particular combinations of sensory information

Question 24

Feature Search

Answer 24

a cognitive strategy in which sensory stimuli are scanned for a specific feature, such as color

Question 25

Sensory Neglect

Answer 25

a condition in which an organism does not respond to sensory stimulation

Question 26

What is the anterior parietal lobe?

Answer 26

primary somatosensory cortex

Question 27

What is the posterior parietal lobe?

Answer 27

association cortex

Question 28

What are the behavioral uses of spatial information?

Answer 28

movement guidance (e.g., reaching/grasping): with object recognition sensorimotor transformation: "body now" to "body future" spatial navigation math language (syntax)

Question 29

What are symptoms of parietal damage?

Answer 29

high sensory thresholds: takes much more intense stimulation before they detect astereognosis asomatognosia: loss of awareness of ownership of a body part (e.g., arm, leg) dyscalculia/acalculia disturbed language function: angular gyrus, organization of letters, syntax of words apraxia (e.g., ideomotor) simultaneous extinction

Question 30

What is apraxia?

Answer 30

can't mimic or repeat actions once they are given tool, they can do it problems sequencing motor actions

Question 31

What is simultaneous extinction?

Answer 31

damage to the right posterior region of the parietal lobe when shown two identical objects: patient sees only the object in his right visual field when shown two different objects: patient sees the object in both visual fields when shown two kinds of an object: patient sees only the object in his right visual field

Question 32

What is attention?

Answer 32

alternes and arousal vigilance selective attention orienting effort and resource capacity: mental workload and task difficulty sensory specific processes

Question 33

What is Posner's attention switching paradigm?

Answer 33

focus on the middle, one box will light up, participants are told that cue is meaningless; target could come on same side or opposite as que valid cue is shown 80% of the time, invalid cue shown 20% there is a longer reaction time for the invalid cue requires a switch; disengage, move, re-engage parietal, superior colliculus, thalamus

Question 34

What are symptoms of posterior parietal lobe damage?

Answer 34

contralateral neglect hemi-inattention ignores or cannot attend to one side of space: contralateral, body midline, multisensory, double simultaneous stimulation technique

Question 35

What is contralateral neglect?

Answer 35

lesion most often in right inferior parietal lobe: right intraparietal sulcus and right angular gyrus, occasionally noted after lesions to frontal lobe and cingulate cortex defective sensation or perception defective attention or orientation

Question 36

What is extinction?

Answer 36

clinical sign: easy to test, doesn't take much assessment patients detect single stimulus either ipsi- or contralesional side of body presenting singular may not reveal deficit fail to detect contralesional stimulus when concurrent stimulus presented on ipsilesional side

Question 37

What is the line bisection task?

Answer 37

ask "draw a line that cuts this line in half" ignore left, can quickly tell they can't see left side performance improves with spatial cue, drawing attention to left side this suggests that there is a problem with attending to left side

Question 38

What is the prism effect?

Answer 38

without prisms, F.D.'s copy of the drawing showed complete neglect of the left side F.D. then examined the drawing for 5 minutes while wearing prisms copies made as much as 2 hours later showed attention to items in the left visual field focuses and engages other areas of the brain that are still intact to help with attentional shifting

Question 39

What is the Bisiach & Luzzatti (1978) plaza experiment?

Answer 39

looking at two stroke survivors with extensive parietal damage; both know area pretty well imagine yourself at far end of the plaza; tell me all the landmarks you see; only said landmarks that are in their right visual field now imagine yourself at the other end facing the other way; still only say the landmarks on their right they know there are landmarks on the left, but only say one's on their right hemineglect is internal, attention must be required to recall things

Question 40

What are the conclusions of the plaza experiment?

Answer 40

memory intact left-side neglect not externally driven attention may be required to recall things attention and memory are intimately linked disengagement problem: have trouble disengaging their attention from the right side unless you help to cue them

Question 41

What are the findings of neurophysiological studies on peripersonal space?

Answer 41

brain areas specialized for coding of visual space surrounding body cells in parietal & frontal cortices, as well as putamen; respond to visual stimuli in spatial proximity to particular body part (e.g., face or hand) bimodal - respond to visual & tactile stimuli (VS, TS) receptive fields for visual stimuli match those for tactile on body surface - even when limb and eyes move suggests these brain regions part of interconnected system for integrated coding of peripersonal space centered on body parts

Question 42

What was the study of right parietal damage patients with tactile extinction in the peripersonal space of their arms?

Answer 42

left tactile extinction was shown when both arms were touched left tactile extinction also occurs with an ipsilesional visual stimulus near hand, same degree as tactile however, far less extinction when visual stimulus presented away from space around hand (anchored to hand)

Question 43

What was the study of right parietal damage patients with tactile extinction in the peripersonal space of their face?

Answer 43

left tactile extinction when both sides of face were touched left tactile extinction also occurs with an ipsilesional visual stimulus near face, same degree as tactile far less extinction when visual stimulus presented away from face suggests crossmodal system exists for hands and face

Question 44

What was the study on is peripersonal space can be modified through tool use?

Answer 44

baseline: minimal extinction pre-tool extinction greater immediately after tool use and when tool in hand back to baseline after 5 minute delay immediate pointing did not lead to extinction system has dynamic properties that may relate to development of tool use in humans & other primates

Question 45

What are the triad of symptoms in Balint's syndrome?

Answer 45

simultagnosia: cannot recognize more than 1 object at a time optic ataxia: deficit in visually-guided reaching oculomotor apraxia: difficulty directing saccades to an object of interest, difficulty in breaking fixation from that object

Question 46

What causes Balint's syndrome?

Answer 46

bilaterally region that has been described as "vision for action"