Cortical organisation and function Flashcards
1
Q
where is the cerebral cortex?
A
covers entire surface of the brain
contains grey matter
2
Q
what do fissures separate?
A
hemispheres and lobes
3
Q
what are Brodmann maps
A
52 regions based cytoarchitecture (cell size, spacing, packing density and layers)
4
Q
how are Brodmann maps useful?
A
areas relate to function e.g primary somatosensory (1,2,3), primary motor (4)
5
Q
what are the different cerebral cortex lobes
A
Frontal
Parietal
Temporal
Occipital
6
Q
what are the functions of the Frontal lobe iM CALM
A
initiating Motor function Cognitive executive function Attention Language Memory
7
Q
what are the functions of the parietal lobe?
A
sensation - touch/pain
sensory aspects of language
spatial orientation and self-perception
8
Q
what are the functions of the occipital lobe?
A
processing visual information
gives meaning to images
9
Q
what are the functions of the temporal lobe
A
processing auditory information
emotions
memories
10
Q
what is contained in the limbic lobe?
A
amygdala, hippocampus, mamillary body, cingulate gyrus
11
Q
what are the functions of the limbic lobe? MEMs and LeaRning
A
MEMs and LeaRning memory emotion motivation learning reward
12
Q
where is the insular lobe?
A
lies deep into lateral fissure
13
Q
what is grey matter?
A
neuronal cell bodies and glial cells
14
Q
what is white matter?
A
myelinated neuronal axons
15
Q
what are the types of white matter tracts?
A
association fibres, commissural fibres, projection fibres
16
Q
what are association fibres?
A
connect areas in same hemisphere
17
Q
what are commissural fibres?
A
connect homologous structures in left and right hemispheres
e.g corpus callosum, anterior commissure
18
Q
what are projection fibres
A
connect cortex to lower brain structures
19
Q
what association fibres connect the frontal and occipital lobe?
A
superior longitudinal fasciculus
20
Q
what association fibres connnect the frontal and temporal lobes, specifically Brocas and Wernickes area?
A
arcuate fasciculus
21
Q
what association fibres connect the temporal and occipital lobes?
A
Inferior longitudinal fasciculus
22
Q
what association fibres connect the frontal and temporal lobes?
A
Uncinate fasciculus
23
Q
where do commissural fibres pass through
A
corpus callosum
24
Q
where do projection fibres converge?
A
through the internal capsule (between the thalamus and basal ganglia)
25
how predictable is function from primary cortices?
easily predictable with left-right symmetry
26
how predictable is function of secondary/association cortices?
less predictable
| left-right symmetry is weak or absent
27
what are the motor areas of the frontal lobe?
primary
supplementary
premotor
28
what does the primary motor area of the frontal lobe control?
fine, discrete voluntary movements
29
what does the supplementary motor area of the frontal lobe control?
planning complex movements, internally cued
30
what does the premotor area of the frontal lobe control?
planning movements, externally cued
31
what area of the frontal lobe controls fine, discrete voluntary movements?
primary motor area
32
what area of the frontal lobe plans complex, internally cued movements?
supplementary motor area
33
what area of the frontal lobe plans movements that are externally cued?
premotor area
34
what areas are contained in the parietal lobe?
primary somatosensory area
| somatosensory association area
35
what is controlled by the primary somatosensory area?
processes somatic sensations arising from receptors in the body
36
what is controlled by the somatosensory association area of the parietal lobe?
interpret the significance of sensory information
| awareness of self and personal space
37
what is controlled by the primary visual area of the occipital lobe?
processes visual stimuli
38
what is controlled by the visual association area of the occipital lobe?
gives meaning and interpretation of visual input
39
what is controlled by the primary auditory area of the temporal lobe?
processes auditory stimuli
40
what is controlled by the auditory association area of the temporal lobe?
gives meaning and interpretation of auditory input
41
what is the prefrontal cortex responsible for? APPSD
```
attention
planning
personality expression
social behaviour
decision making
```
42
what is the brocas area responsible for?
motor aspect of speech, production of language
43
where is the Brocas area?
left frontal lobe, just above sylvian fissure
44
what is Wernicke's area responsible for?
understanding and comprehension of language
45
where is Wernicke's area found?
left temporal lobe, superiorly and caudally
46
what is the result of a frontal lobe lesion?
changes in personality, inappropriate behaviour
47
what is the result of a parietal lobe lesion?
contralateral neglect
lack of awareness of self on opposite side
lack of awareness of opposite side of extrapersonal space
48
what is the result of a temporal lesion?
agnosia (inability to recognise)
| possible anterograde amnesia
49
what is Brocas aphasia?
expressive aphasia - poor production of speech, comprehension intact
50
what is Wernicke's aphasia?
receptive aphasia - poor comprehension of language
51
what would a lesion to the primary visual cortex of the occipital lobe cause?
blindness in the corresponding part of the visual field
52
what would a lesion to the visual association area of the occipital lobe cause?
deficits in interpretation of visual information e.g prosopagnosia
53
what are the 4 main methods of assessing cortical function?
Positron emission tomography (PET)
functional magnetic resonance imaging (fMRI)
electroencephalography (EEG)
magnetoencephalography (MEG)
54
what is a PET scan?
demonstrates the blood flow directly to a brain region
55
what is an fMRI scan?
basically a PET using radioactive isotopes of glucose
| demonstrates amount of blood oxygen in brain regions
56
what is an EEG?
measures electrical signals produced by the brain
57
what is an MEG?
measures magnetic signals produced by the brsin
58
what are visual evoked potentials?
type of encephalography
| stimulates visual sensations
59
what are somatosensory evoked potentials?
series of waves that reflect sequential activation of neural structures along the somatosensory pathways
60
what is transcranial magnetic stimulation?
assesses functional integrity of neural circuits, using electromagnetic induction to stimulate neurones
61
what is transcranial direct current stimulation
uses low direct current over the scalp to increase or decrease neuronal firing rates
62
what is diffusion tensor imaging?
scan based on the diffusion of water molecules
63
what is diffusion tensor imaging with tractography?
3D reconstruction of brain to assess neural tracts
64
Mnemonic for insular lobe?
```
Insurance AVIVA
Auditory processing
Visual vestibular integration
Interoception
Visceral sensation
Autonomic control
```
65
How to tell brocas and wernickes aphasia apart
Broca C D Expressive aphasia
| Wernickes V U T S Receptive aphasia
66
what is multiple sclerosis?
demyelination of neurones due to autoimmune attack of oligodendrocytes (CNS)
characterised by 2 different areas affected with episodic neurological dysfunction
67
symptoms of MS?
```
fatigue
difficulty walking
blurred vision
bladder control issues
numbness/tingling
stiffness/spasms
balance/coord issues
cognitive issues
```
68
what is the inflammation process of MS?
driven by perivascular and leptomeningeal (arachnoid and pia mater) immune cell infiltration (CD3 T cells, CD20 B cells)
inflammation - demyelination - axonal loss - neurodegeneration
69
risk factors for MS
```
family history
female
other autoimmune
vit D deficiency as a child
epstein-barr virus
smoking
```
70
types of MS
relapsing-remitting
primary progressive
secondary progressive - may also have relapse/remiss and faster progression than primary
progressive-relapsing - progressive worsening and acute relapses with no remission
71
MS early symptoms
ocular pain, blurred vision (optic neuritis)
72
path of projection fibres?
corona radiata
to internal capsule
into descending white matter tracts (brainstem/spinal cord)
73
types of association fibres
short fibres - U fibres - connect adjacent gyri within same hemisphere
long fibres - connect distal regions within same hemisphere
74
what is an M-wave
fast twitch
motor activation - orthrodromic (towards muscle)
electrical stimulus - activates motor axons orthodromically - action potentials - muscle contraction
75
what is an H-reflex
slow twitch - orthrodromic sensory activation
electrical stimulus - activates sensory axons orthodromically - action potentials to spinal cords - lower motor neurons - muscle contraction
76
what is an F-wave
slowest muscle twitch
antidromic motor activation (goes backwards through spinal cord - opposite of normal motor M wave)
large electrical stimulus only - activates motor axons antidromically - action potentials to spinal cord - backfire to lower motor neurons - muscle contraction
77
what do CNS demyelinations show on an EMG
slowed motor neuron latency in CNS so prolonged CMCT (central motor conduction time)
78
calculation for peripheral motor conduction time (PMCT)
(M latency + F latency-1) /2
-1 is for turnaround time in spinal cord of F wave
79
how do we measure motor evoked potential latency (total motor conduction time)
transcranial magnetic stimulation (TMS)
measured with an EMG to see how long it takes from activation of motor cortex to muscle contraction
80
what is total motor conduction time (TMCT)
time taken from stimulation of primary motor cortex by TMS to the contraction of muscle (measured by EMG)
81
what is peripheral motor conduction time measuring
time from spinal cord to muscle along motor axon
82
how to calculate central motor conduction time
TMCT - PMCT
83
how do we know if there is an issue of conduction of CNS neurons? (MS)
longer MEP - could be upper MN, lower MN, both (longer TMCT)
peripheral nerve stim - normal F wave (so normal PMCT) indicates no issue with lower MN
AKA total motor conduction time delayed with normal peripheral motor conduction time
