parietal lobes

what does the parietal lobe do

process and integrate somatosensory and visual information — especially for control of motement

Parieto-occipital sulcus

posterior border

central sulcus

anterior border

lateral fissure

ventral border

precuneus

dorsal to cingulate gyrus on medial side

postcentral gyrus brodmann’s

1, 2, and 3

parietal operculum brodmann’s

43

superior parietal lobule brodmann’s

5 and 7

supra marginal gyrus brodmann’s

40

angular gyrus brodmann’s

39

2 function zones of parietal lobes

anterior zone and posterior zone

anterior zone brodmann’s

1, 2, 3, and 43

posterior zone brodmann’s

5, 7, 40, 39

anterior zone

somatosensory cortex

somatic sensations and perceptions

posterior zone

posterior parietal cortex

integration of sensory input for control of movement

“cognitive”

what does posterior parietal need for integration

internal representation of location of objects, common to all the senses for integration (neural representation of space)

posterior parietal cortex — object recognition

determine relations between objects

object centered system — details of objects are important (along with temporal lobe — ventral stream and STS)

posterior parietal cortex — guidance of movement

viewer centered (egocentric) movements

direct movement and detect stimuli in space

transform sensory information into guidelines for directing attention and guiding action

sensorimotor transformation

neural calculations of relative position of the body with respect to sensory feedback from movements being made and planned for future

implications for neuroprosthetics (PRR, parietal reach region)

spatial navigations

cognitive spatial maps and mental lists of what we do at each location

route knowledge, unconscious knowledge of how to reach a destination (MPR — medial parental region, posterior cingulate)

acalculia

inability to do arithmetic

noted in parietal lobe patients (left temporo-parietal junction)

might result from spatial properties of addition and subtraction

what do lesions to the poscentral gyrus produce

abnormally high somatosensory thresholds (2 point test on skin)

impaired position sense, deficits in stereognosis, or tactile perception

afferent paresis

afferent paresis

clumsy finger movements due to lack of feedback about finger position

asterognosis

inability recognize an object by touch

simultaneous extinction

two stimuli are applied simultaneously to opposite sides of body

failure to report a stimulus on one side is referred to as extinction

numb touch or blind touch

cannot feel touch on skin, but can identify where on skin was touched

somatoperceptual symptoms of parietal lobe lesions

asterognosis

simultaneous extinction

numb touch or blind touch

asomatognosias

loss of knowledge or senses of one’s own body and bodily conditions (added appearance or disappearance)

types of asomatognosias

anosognosia

anosodiaphoria

autopagnosia

asymbolia for pain

anosognosia

unawareness or denial of illness

anosodiaphoria

indifference to illness

autopagnosia

inability to localize and name body parts (most commonly the different fingers: don’t know index from pinky; symptom of spina bifida)

asymbolia for pain

absence of normal reactions to pain (like automatically pulling band back from a fire)

ballet’s syndrome

often bilateral PPC damage associated with peculiar visual symptoms

symptoms of ballet’s syndrome

oculomotor apraxia

optic ataxia

simultagnosia

oculomotor apraxia

can move eyes but do not land on the visual target intended

optic ataxia

cannot visually guide hand to object (overshoot/undershoot)

simultagnosia

cannot perceive the visual field as a whole

symptoms of right posterior parietal lobe damage

contralateral neglect

object recognition deficits

contralateral neglect

neglect for visual, auditory, and somesthetic stimulation on one side of the body or space

right intraparietal sulcus and the right angular gyrus

orientation or integration problem are top theories

object recognition deficits

deficit in recognizing objects in unfamiliar views

deficit is not in forming a concept, but in perceptual classification

type of spatial matching

symptoms of left posterior parietal lobe damage

gerstmann syndrome

disturbed language function

aprazias

gerstmann syndrome symptoms

ringer agnosia

right-left confusion

agraphia (can’t write)

acalculia (can’t do math)

gerstmann syndrome cause

left inferior parietal lobe lesion — angular gyrus

disturbed language function

agraphia, dyslexia, dysphasia

apraxias

loss of skilled movement

not due to weakness, inability to move, abnormal muscle tone, intellectual deteriorate, poor comprehension, or other disorders of movemetn

ideomotor and constructional

ideomotor apraxia

unable to copy movements

constructional apraxia

can’t build following a model or work a puzzle or draw a picture

what is mental rotation associated with?

better white matter organization — specifically in the IPS (intraparietal sulcus) of the PPC

other symptoms of posterior parietal lobe damage

spatial cognition disorders

drawing (deficits in drawing after damage to right parietal lobe)

spatial cognition disorders

inability to manipulate the image and use topographic

loss of memory of familiar surroundings

inability to locate items on a map

inability to navigate in own environment

clinical neuropsychological assessment for parietal damage

two point discrimination

form board test

line bisection test

mooney closure test

right-left test

kimura box test

token test

two point discrimination test

heightened threshold

postcentral gyrus

form board test

tactile perception

?

line bisection test

contralateral neglect

R PPC

mooney closure test

visual perception ability

R TPJ

also ventral stream

right-left test

asomatagnosia

LPPC

Kimura box test

apraxia

L PPC

token test

language apraxia

L TPJ?