frontal and parietal lobes

Question 1

what is the longitudinal fissure?

Answer 1

separates the right and left hemisphere

Question 2

what are fissures?

Answer 2

deep sulci/grooves

Question 3

what are the boundaries of the parietal lobe?

Answer 3

central sulcus (Rolandic fissure)

parieto-occipital fissure

lateral sulcus (sylvian fissure)

no clear macro-anatomical border

Question 4

what is the central sulcus (Rolandic fissure)?

Answer 4

parietal boundary with frontal lobe

Question 5

what is the parieto-occipital fissure?

Answer 5

parietal boundary with occipital lobe

Question 6

what is the lateral sulcus (sylvian fissure)?

Answer 6

parietal boundary with temporal lobe

Question 7

what does macro-anatomical mean?

Answer 7

based on sulci and gyri

Question 8

what are the major anatomical subdivisions of the parietal lobe?

Answer 8

postcentral gyrus (strip)

posterior parietal lobe (superior parietal lobule, intraparietal sulcus), inferior parietal lobule

Question 9

what are the major functional subdivisions of the parietal lobe?

Answer 9

primary somatosensory cortex (S1)

posterior parietal cortex (intraparietal sulcus and superior parietal lobule, right inferior parietal lobule, left anterior inferior parietal lobule, left posterior inferior parietal lobule)

Question 10

what is the main role of the S1?

Answer 10

processing information about body sensations (touch, pain, proprioception - map of various body part locations)

Question 11

what four subdivisions can the S1 be divided into?

Answer 11

areas 1, 2, 3a, 3b

Question 12

where is the input to the S1 mainly from?

Answer 12

thalamus

motor cortex

Question 13

where is the output from the S1 mainly to?

Answer 13

motor cortex
posterior parietal cortex

Question 14

what did Penfield and Boldrey (1937) do?

Answer 14

inserted electrodes in somatosensory cortex of epileptic patients just before operating on them

patients were under local anaesthesia

stimulated different parts of somatosensory cortex and recorded sensations reported by patients

led to creation of simplified (and partially correct) somatotopic map

Question 15

what was Wilder Penfield’s somatotopic map?

Answer 15

somatosensory homunculus

some body parts have larger dedicated area than others

while there is clear somatotopy, it’s not as simple as depicted by Penfield

Question 16

why do we study the S1?

Answer 16

learn about brain organisation in general

learn about brain reorganisation

Question 17

when can the brain be reorganised?

Answer 17

after injuries (phantom limbs and phantom pain after amputations, reintegration of a body part after transplants)

through learning

brain is more dynamic than we assume

functional reorganisation of S1 can occur within just 24 hours

Question 18

what was Kolasinski et al’s (2016) study into the S1?

Answer 18

mapped digits onto fingers

glue middle and ring finger together

how quick body would accept it

the fingers start behaving as one after 24 hours

Question 19

what are the different subsections of the posterior parietal cortex?

Answer 19

intraparietal sulcus and superior parietal lobule

left anterior inferior parietal lobule

left posterior inferior parietal lobule

Question 20

what is the intraparietal sulcus and superior parietal lobule?

Answer 20

vision for action

overarching concept = vision for action - dorsal visual stream

Balint syndrome

Question 21

what is the vision for action (dorsal visual stream) overarching concept of the superior parietal lobule?

Answer 21

is there an object with which I can interact? what is its size and orientation? - objects in space, object relevance/attention

where is my body (arms, hands, eyes, fingers) relative to the object? - reaching/grasping objects

Question 22

what do the more anterior areas of the superior parietal lobule do?

Answer 22

coding in hand-centred coordinate system

Question 23

what do the more posterior areas in the superior parietal lobule do?

Answer 23

coding in vision-central coordinate system (retinotopy)

Question 24

what is Balint’s syndrome?

Answer 24

classic neuropsychological syndrome after bilateral lesions (in superior parietal lobule)

optic ataxia

oculomotor apraxia

simultanagonisa

Question 25

what is optic ataxia?

Answer 25

deficit in visually guided reaching movements

Question 26

what is oculomotor apraxia?

Answer 26

inappropriate fixation of gaze and difficulties in voluntarily shifting fixation to other objects

Question 27

what is simultanagnosia?

Answer 27

impaired ability to perceive multiple items in a visual display

Question 28

what rudimentary mechanisms might the superior parietal lobule's involvement in cognitive functions derive from?

Answer 28

visuospatial working memory - link to representing the location of objects, coding what is relevant mental rotation/imagery - link to manipulating objects arithmetic - link to moving eyes/hands to count, spatial layout ("mental number line")

Question 29

what does the right inferior parietal lobule do?

Answer 29

detect salient events in environment, shift attention

Question 30

what do lesions in the right inferior parietal lobule result in?

Answer 30

hemispatial neglect

Question 31

what was Singh-Curry and Husain's (2009) study into the right inferior parietal lobule?

Answer 31

detection and encoding of salient or novel events (bottom-up attention - brain interprets) sustaining attention on current task goals key role in maintaining attention on current task goal as well as encoding salient events so that task-sets can be speedily reconfigured to deal with new challenges

Question 32

what does the left anterior inferior parietal lobule do?

Answer 32

use objects in an appropriate way pantomime object use

Question 33

what was Reynaud et al's (2016) study into the left anterior inferior parietal lobule?

Answer 33

understanding tool-use actions lesion in this area - apraxia with possible impairments imitation of gestures, communicative gestures (pantomime thumbs up/object) real tool use

Question 34

what does the left posterior inferior parietal lobule do?

Answer 34

detect salient events in one's thoughts integrative account for more posterior areas

Question 35

what was Seghier's (2012) study into the left posterior inferior parietal lobule?

Answer 35

semantic processing reading and comprehension default mode processing (mind wandering) number processing memory retrieval theory of mind

Question 36

what is the more integrative account for more posterior areas of the left posterior inferior parietal lobule?

Answer 36

bottom up attention to internally generated stimuli contrasts from the right inferior parietal lobule which relies on bottom-up information from environmental stimuli

Question 37

why might the inferior parietal cortex and lateral prefrontal cortex be special?

Answer 37

one possibility why function could be difficult to understand animal models might not work for these areas

Question 38

what are the three main subdivisions on the frontal cortex?

Answer 38

based on cytoarchitectonics (look at cell structures within brain) primary motor cortex (M) - giant Betz cells in layer V premotor cortex (PM) - no granular cells in layer IV prefrontal cortex (PF) - granular cells in layer IV

Question 39

where is the frontal lobe in Brodmann's (1909) classic cytoarchitectonic map?

Answer 39

primary motor - Brodmann area (BA) 4 premotor - BA 6 transition ("dysgranular") - BA44 prefrontal - BA's 8, 9, 10, 11, 45, 46, 47

Question 40

what is MRI-based multimodal parcellation?

Answer 40

strong evidence that there are more areas than identified by Brodmann

Question 41

what is the motor cortex?

Answer 41

control of skeletal muscles together with other structures, most notably basal ganglia, thalamus and cerebellum roughly somatotopically organised ("motor humunculus")

Question 42

what is the premotor cortex?

Answer 42

higher-order motor control movement planning movement selection movement sequencing inhibitory control of motor cortex (supplementary motor area on medial side of hemisphere)

Question 43

what are traditional approaches to looking at the neuropsychology of the prefrontal cortex?

Answer 43

neuropsychological tests conducted on patients with frontal lesion deficits verbal fluency (Milner, 1964) - "write down as many words beginning with F as possible", 1 minute then A and S Wisconsin Card Sorting Test (WCST - Milner, 1964) - perseveration = continue to use "no longer correct rule" Stroop task (Perret, 1974) Tower of London (Shallice, 1982)

Question 44

what are the issues with traditional approaches to looking at the prefrontal cortex?

Answer 44

poor sensitivity and specificity which function is impaired?

Question 45

how is poor sensitivity and specificity an issue in traditional approaches?

Answer 45

sensitivity = ability of test to identify those with prefrontal lesions (and are impaired) specificity = ability of test to not identify those impaired by lesions in other areas not all patients with prefrontal lesions have difficulties some patients with non-lesions have difficulties

Question 46

how is not knowing which function is impaired an issue with traditional approaches?

Answer 46

perseveration in WCST working memory issue? long-term memory issue? difficulties suppressing old new rule? difficulties activating new rule? sustained attention issue? issue known as problem impurity of tasks dangerous to conclude deficit lies in process required by task

Question 47

what are recent approaches to studying the frontal lobe?

Answer 47

basic approach lesion-symptom

Question 48

what is the basic recent approach to studying the frontal lobe?

Answer 48

devise simple tests - single processes manipulate difficulty and context - more complex processes based on Norman and Shallice's Supervisory Attention System

Question 49

what were Stuss's conclusions about the lateral prefrontal cortex?

Answer 49

executive function left = task setting right = monitoring

Question 50

what were Stuss's conclusions about the dorsomedial prefrontal cortex?

Answer 50

energisation process of initiating and sustaining any response

Question 51

what were Stuss's conclusions about the orbital prefrontal cortex?

Answer 51

behavioural and emotional self-regulation

Question 52

what were Stuss's conclusions and the polar pre-frontal cortex?

Answer 52

metacognition "thinking about thinking"

Question 53

what is the evaluation of Stuss et al's approach?

Answer 53

lesion-symptom mapping is interesting (further refined with modern structural MRI - voxel-based lesion-symptom mapping) exact processes are still unclear (are the tasks really process-pure? are the labels like energisation appropriate? - cover all deficits) general problems with patient studies (small sample sizes, lesions restricted to grey/white but not both)

Question 54

what is the final evaluation for the function of the left prefrontal cortex?

Answer 54

adaptivity is plausible but is restricted - not every area can represent everything hierarchical organisation is plausible but exact processes are still quire unclear relationship to Stuss's neuropsychological results not clear (e.g. suggested hemispheric specialisation) needed = computational models combined with experimental evidence (brain imaging, brain stimulation, lesion)