1
Q
How is the cerebral cortex organised microscopically?
A
Layers and columns
2
Q
What is cytoarchitecture?
A
Cell size, spacing or packing density and
layers
3
Q
What neurologist identified 52 regions based on cytoarchitecture?
A
Brodmann
4
Q
What are the functions of the frontal lobe?
A
- Regulating and initiating motor function
- Language
- Cognitive functions (executive function
[e.g. planning]) - Attention
- Memory
5
Q
What are the functions of the parietal lobe?
A
- Sensation - touch, pain
- Sensory aspects of language
- Spatial orientation and self-perception
6
Q
What are the functions of the occipital lobe?
A
- Processing visual information
7
Q
What are the functions of the temporal lobe?
A
- Processing auditory information
- Emotions
- Memories
8
Q
What are the functions of the limbic lobe?
A
- Learning
- Memory
- Emotion
- Motivation
- Reward
9
Q
What does the limbic lobe include?
A
- Amygdala
- Hippocampus
- Mamillary body
- Cingulate gyrus
10
Q
What are the functions of the insular cortex?
A
- Visceral sensations
- Autonomic control
- Interoception
- Auditory processing
- Visual-vestibular integration
11
Q
Where can the insular cortex?
A
Deep within the lateral fissure
12
Q
What is grey matter?
A
Neuronal cell bodies and glial cells
13
Q
What is white matter?
A
Myelinated neuronal axons arranged in tracts
14
Q
What do white matter tracts do?
A
Connect cortical areas
15
Q
What are 3 types of white matter tracts?
A
- Association fibres
- Commissural fibres
- Projection fibres
16
Q
What do association fibres do?
A
Connect areas within the same hemisphere
17
Q
What fibres connect areas within the same hemisphere?
A
Association fibres
18
Q
What do commissural fibres do?
A
Connect homologous structure in left and right hemispheres
19
Q
What fibres connect homologous structure in left and right hemispheres?
A
Commissural fibres
20
Q
What do projection fibres do?
A
Connect cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)
21
Q
What fibres connect cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)?
A
Projection fibres
22
Q
What types of association fibres are there?
A
- Superior Longitudinal Fasciculus
- Arcuate Fasciculus
- Inferior Longitudinal Fasciculus
- Uncinate Fasciculus
23
Q
What association fibres are long?
A
- Superior Longitudinal Fasciculus
2. Arcuate Fasciculus
24
Q
What association fibres are short?
A
- Inferior Longitudinal Fasciculus
2. Uncinate Fasciculus
25
What does the Superior Longitudinal Fasciculus connect?
Connects frontal and occipital lobes
26
What does the Arcuate Fasciculus connect?
Connects frontal and temporal lobes
27
What does the Inferior Longitudinal Fasciculus connect?
Connects temporal and occipital lobes
28
What does the Uncinate Fasciculus connect?
Connects anterior frontal and temporal lobes
29
What connects frontal and occipital lobes?
Superior Longitudinal Fasciculus
30
What connects frontal and temporal lobes?
Arcuate Fasciculus
31
What connects temporal and occipital lobes?
Inferior Longitudinal Fasciculus
32
What connects anterior frontal and temporal lobes?
Uncinate Fasciculus
33
What types of commissural fibres are there?
1. Corpus callosum
| 2. Anterior commissure
34
What types of projection fibres are there?
1. Afferent
| 2. Efferent
35
What do projection fibres deep to the cortex radiate as?
Corona radiata
36
Where do projection fibres converge through?
Through internal capsule between thalamus and basal ganglia
37
Where are the motor areas found?
Frontal lobe
38
What does the primary motor area do?
1. Controls fine, discrete, precise voluntary
movements.
2. Provides descending signals to execute
movements.
39
What does the supplementary motor area do?
Involved in planning complex movements (e.g.
| internally cued, e.g. speech)
40
What does the premotor area do?
Involved in planning movements (e.g. externally cued)
41
Where is the somatosensory area located?
Parietal lobe
42
What does the primary somatosensory area do?
Processes somatic sensations arising from receptors in the body.
43
What does the somatosensory association area do?
1. Interpret significance of sensory information, e.g. recognizing an object placed in the hand.
2. Awareness of self and awareness of personal space
44
What somatic sensations arise from receptors in the body?
1. Fine touch
2. Vibration
3. Two-point discrimination
4. Proprioception
5. Pain
6. Temperature
45
Where is the visual area located?
Occipital lobe
46
What does the primary visual area do?
Processes visual stimuli
47
What does the visual association area do?
Gives meaning and interpretation of visual input
48
Where is the auditory area located?
Temporal lobe
49
What does the primary auditory area do?
Processes auditory stimuli
50
What does the auditory association area do?
Gives meaning and interpretation of auditory input
51
What does the prefrontal cortex do?
1. Attention
2. Adjusting social behaviour
3. Planning
4. Personality expression
5. Decision making
52
What does Broca's area ddo?
Production of language
53
What does Wernicke's area do?
Understanding of language
54
What do frontal lobe lesions cause?
1. Changes in personality
| 2. Inappropriate behaviour
55
What do parietal lesions cause?
1. Contralateral neglect
2. Lack of awareness of self on left side (if lesion on right hemisphere)
3. Lack of awareness of left side of extrapersonal space
56
What do temporal lesions cause?
Agnosia
57
What is it called if you cannot form new memories?
Anterograde amnesia
58
What is anterograde amnesia?
Can not form new memories
59
What is agnosia?
Inability to recognise
60
What is the inability to recognise called?
Agnosia
61
What white motor tract connects Broca's area and Wernicke's area?
Arcuate fasciculus
62
What does a lesion to Broca's area cause?
Expressive aphasia
63
What does a lesion to Wernicke's area cause?
Receptive aphasia
64
What is expressive aphasia?
Poor production of speech, comprehension intact
65
What lesion causes expressive aphasia?
Broca's area
66
What is receptive aphasia?
Poor comprehension of speech, production is fine
67
What lesion causes receptive aphasia?
Wernicke's area
68
What lesion leaves speech comprehension intact?
Broca's area
69
What lesion leaves speech production intact?
Wernicke's area
70
What does a lesion in the primary visual cortex cause?
Blindness in the corresponding part of the visual field
71
What does a lesion in the visual association area cause?
Deficits in interpretation of visual information e.g. prosopagnosia
72
What is prosopagnosia?
Inability to recognise familiar faces or learn new faces (face blindness)
73
What is inability to recognise familiar faces or
| learn new faces (face blindness) called?
Prosopagnosia
74
What imaging techniques can assess cortical function?
1. PET - positron emission tomography
| 2. fMRI - function magnetic resonance imaging
75
What does PET measure?
Blood flow directly to a brain region
76
What does fMRI measure?
Amount of blood oxygen in a brain region
77
What encephalography techniques can assess cortical function?
1. EEG - electroencephalography
| 2. MEG - magnetoencephalography
78
What does EEG measure?
Measures electrical signals produced by the the brain
79
What does MEG measure?
Measures magnetic signals produced by the brain
80
Describe the localisation of function for primary cortices?
- Function predictable
- Organised topographically
- Symmetry between left and right
81
Describe the localisation of function for secondary cortices?
- Function less predictable
- Not organise topographically
- Left-right symmetry weak/absent
82
How could encephalography be used to access cortical function?
1. Visual evoked potentials
2. Event-related potentials/evoked-potentials
3. Somatosensory evoked potentials
83
How could somatosensory evoked potentials in encephalography be used to access cortical function?
Series of waves that reflect sequential activation of neural structures along the somatosensory pathways.
84
What brain stimulation be used to assess cortical function?
1. TMS - transcranial magnetic stimulation
| 2. tDCS - transcranial direct current stimulation
85
What does TMS do?
Uses electromagnetic induction to stimulate neurones
-> assess the functional integrity of neural circuits
86
What can TMS assess in cortical function?
1. Investigate neuronal interactions controlling movement (stimulate primary motor cortex) following spinal cord injury
2. Investigate whether a specific brain area is responsible for a function e.g. speech
87
What does tDCS do?
Uses low direct current over the scalp to increase or decrease neuronal firing rates
88
What imaging techniques can be used to assess structure?
DTI - diffusion tensor imaging
89
What is DTI?
Based on diffusion of water molecules
90
What is DTI with tractography?
3D reconstruction to assess neural tracts
91
What is MS - multiple sclerosis?
MS is an autoimmune disorder which results in the loss of myelin from neurons of the CNS
92
What are some of the main symptoms of MS?
- Blurred vision
- Fatigue
- Difficulty walking
- Paraesthesia (numbness or tingling in different parts of the body)
- Muscle stiffness and spasms
93
What is orthodromic?
Travelling in the normal direction in a nerve fibre
94
What is antidromic?
Travelling in the opposite direction to the normal in a nerve fibre
95
What is M-wave in peripheral nerve stimulation?
The fast response - the activation of the motor axons can cause action potentials to travel along the nerve to cause muscle contraction, a twitch.
96
How can results peripheral nerve stimulation be recorded?
EMG - electromyography
97
What is H-reflex in peripheral nerve stimulation?
Reflex activation of a muscle - same stimulus cause activation of the sensory axons (feel stimulus).
- The action potentials can travel along the nerve to the spinal cord.
- These can then cause the lower motor neurons in the spinal cord to become activated.
- Action potentials in the motor axons can travel along the motor neuron to the muscle where they cause muscle contraction, a twitch.
98
When can an F wave be seen?
With a large enough stimulus
99
What is F-wave in peripheral nerve stimulation?
A large electrical stimulus can cause activation of the motor axons to conduct antidromically.
- These action potentials travel along the motor nerve to the spinal cord (i.e. in the opposite way to normal).
- These can then cause the lower motor neurons in the spinal cord to become activated.
- Action potentials in the motor axons can travel along the motor neuron to the muscle where they cause muscle contraction, a twitch.
100
How does cortical motor stimulation using TMS work?
The activation of the upper motor neurons causes action potentials to travel along the entire motor pathway (upper and lower motor neurons) to cause muscle contraction.
101
How does cortical motor stimulation using TMS result in?
EMG response known as an MEP - motor evoked potential.
102
What is the TMCT?
Total Motor Conduction Time:
| Time from brain to muscle (MEP latency)
103
What is the PMCT?
Peripheral motor conduction time:
| time from spinal cord to muscle along motor axon
104
How is PMCT calculated?
PMCT = (M latency + F latency-1) /2
105
What is the -1 in PMCT calculation?
The -1 is the estimated time for the action potentials arriving at the lower motor neuron cell body to turn around
106
What is CMCT?
Central Motor Conduction Time
107
How is CMCT calculated?
TMCT - PMCT
108
What is the effect of MS on brain stimulation?
Longer than usual MEP latency.
| Problem along upper motor neurons, lower motor neurons or both.
109
What is the effect of MS on TMCT?
Delayed
110
What is the effect of MS on peripheral nerve stimulation?
Normal F wave latency.
| No issue with lower motor neurons.
111
What is the effect of MS on brain stimulation?
Normal
112
How can we deduce where the problem is in MS?
TMCT (brain stimulation) delayed
PMCM (peripheral nerve stimulation) normal
-> problem in CNS
