Cortical Organisation And Function

Question 1

List the functions of the frontal lobe

Answer 1

Regulating and initiating motor function
Language
Cognitive functions, e.g. planning
Attention
Memory

Question 2

List the functions of the parietal lobe

Answer 2

Sensation - touch, pain
Sensory aspects of language
Spatial orientation and self-perception

Question 3

List the functions(s) of the occipital lobe

Answer 3

Processing visual information

Question 4

List the functions of the temporal lobe

Answer 4

Processing auditory information
Emotions
Memories

Question 5

What areas comprise the limbic lobe and what is its function?

Answer 5

Amygdala, hippocampus, mamillary body, and cingulate gyrus
Involved in learning, memory, emotion, motivation and reward

Question 6

Where is the insular cortex and what is its function?

Answer 6

Lies deeps within lateral fissure
Concerned with visceral sensations, autonomic control, and interoception, auditory processing and visual-vestibular integration

Question 7

What comprises the grey matter of the brain?

Answer 7

Neuronal cell bodies and glial cells

Question 8

What comprises the white matter of the brain?

Answer 8

Myelinated neuronal axons arranged in tracts

Question 9

What are the different types of white matter tract fibres and what do they do?

Answer 9

Association fibres - connect areas within the same hemisphere
Commissural fibres - connect homologous structure in left and right hemispheres
Projection fibres - connect cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)

Question 10

Name the different association fibres and what they connect

Answer 10

Superior Longitudinal Fasciculus - connects frontal and occipital lobes
Arcuate Fasciculus - connects frontal and temporal lobes
Inferior Longitudinal Fasciculus - connects temporal and occipital lobes
Uncinate Fasciculus - connects anterior frontal and temporal lobes

Question 11

Give two examples of commissural fibres

Answer 11

Corpus callosum
Anterior commissure

Question 12

What can a corpus callosotomy/hemispherectomy be used to treat?

Answer 12

Severe epilepsy

Question 13

What do the terms ‘afferent’ and ‘efferent’ describe in terms of projection fibres?

Answer 13

Afferent - towards cortex
Efferent - away from cortex

Question 14

What do projection fibres radiate as deep to the cortex?

Answer 14

Corona radiata

Question 15

What do projection fibres converge to form?

Answer 15

Internal capsule between thalamus and basal ganglia

Question 16

What is the difference in localisation of function between primary and secondary/association cortices?

Answer 16

Primary:
- predictable function
- topographic organisation
- symmetry between left and right cortices
Secondary:
- function less predictable
- organisation not topographic
- weak or absent left-right symmetry

Question 17

What is the function of the primary motor cortex?

Answer 17

Controls fine, discrete, precise voluntary movements
Provides descending signals to execute movements

Question 18

What is the function of the supplementary motor area?

Answer 18

Involved in planning complex movements (e.g. internally cued)

Question 19

What is the function of the premotor area?

Answer 19

Involved in planning movements (e.g. externally cued)

Question 20

What is the function of the primary somatosensory cortex?

Answer 20

Processes somatic sensations arising from receptors in the body (e.g. fine touch, vibration, two-point discrimination, proprioception, pain and temperature)

Question 21

What is the function of the somatosensory association area?

Answer 21

Interpret significance of sensory information, e.g. recognizing an object placed in the hand
Awareness of self and awareness of personal space

Question 22

What is the difference between the function of the primary visual cortex and visual association area?

Answer 22

Primary visual - processing visual stimuli
Visual association - gives meaning and interpretation of visual input

Question 23

What is the difference between the function of the primary auditory cortex and auditory association area?

Answer 23

Primary auditory - processing auditory stimuli
Auditory association - gives meaning and interpretation of auditory input

Question 24

What is the prefrontal cortex involved in?

Answer 24

Attention
Adjusting social behaviour
Planning
Personality expression
Decision making

Question 25

What is Broca’s area involved in?

Answer 25

Production of language

Question 26

What is Wernicke’s area involved in?

Answer 26

Understanding of language

Question 27

What are some consequences of frontal lobe lesions?

Answer 27

Changes in personality
Inappropriate behaviour

Question 28

What are some consequences of parietal lobe lesions?

Answer 28

Contralateral neglect
- lack of awareness on side opposite to lesion
- lack of awareness of extrapersonal space on contralateral side

Question 29

What are some consequences of temporal lobe lesions?

Answer 29

Lateral and medial lesions
Agnosia - inability to recognise
Anterograde amnesia - can’t form new memories

Question 30

What are the consequences of lesions to Broca’s area and Wernicke’s area?

Answer 30

Broca’s area - expressive aphasia - poor production of speech, however comprehension intact (can understand speech)
Wernicke’s area - receptive aphasia - poor comprehension of speech, production is fine

Question 31

What is a consequence of a lesion to the primary visual cortex?

Answer 31

Blindness in corresponding part of visual field

Question 32

What is a consequence of a lesion to the visual association area?

Answer 32

Deficits in interpretation of visual information e.g. prosopagnosia: inability to recognise familiar faces or learn new faces (face blindness)

Question 33

What are the different types of imaging used to assess cortical function and how do they work?

Answer 33

Positron emission tomography (PET) - shows blood flow directly to a brain region
Functional magnetic resonance imaging (fMRI) - shows amount of blood oxygen in a brain region
Electroencephalography (EEG) - measures electrical signals produced by the brain
Magnetoencephalography – (MEG) - measures magnetic signals produced by the brain

Question 34

What is the relevance of event-related/evoked potentials?

Answer 34

These potentials are stimulated (rather than just monitoring sleep or daily activities) to assess function as compared to the ‘normal’ function expected by a healthy individual - delays in potentials may suggest an issue with that area

Question 35

What do somatosensory evoked potentials allow us to assess through encephalography?

Answer 35

Series of waves that reflect sequential activation of neural structures along the somatosensory pathways
E.g. stimulus to median nerve:
Can observe impulse arriving at shoulder, mid cervical cord activity, thalamic activity and somatosensory activity - can identify where they are delays

Question 36

What is transcranial magnetic stimulation?

Answer 36

Use of electromagnetic induction to stimulate neurons
Can assess the functional integrity of neural circuits

Question 37

How does transcranial direct current stimulation (tDCS) work?

Answer 37

Uses low direct current over the scalp to increase or decrease neuronal firing rates

Question 38

What is diffusion tension imaging (DTI) based on?

Answer 38

Based on diffusion of water molecules

Question 39

What does DTI with tractography allow you to assess?

Answer 39

3D reconstruction
Can assess neural tracts