Cortical Organisation And Function

Question 1

What is the cerebral cortex?

Answer 1

Covers entire surface of brain

Contains grey matter

Gyri and sulci

Organised into lobes

Organised into layers and columns (don’t really need to know). Classification by this sorts it into 52 regions based on cyto architecture

Question 2

What are the lobes of the brain?

Answer 2

Frontal

Parietal

Temporal

Occipital

Question 3

What does the frontal lobe do?

Answer 3

Regulates and initiates motor function (contains primary motor cortex)

Language

Executive cognitive function (eg. Planning)

Attention

Memory

Decision making

Question 4

What is the parietal lobe?

Answer 4

Sensation- touch, pain
(Contains primary somatosensory cortex)

Sensory aspects of language

Spatial orientation and self perception (interoception)

Question 5

What is the occipital lobe ?

Answer 5

Processes visual information - ascribes meaning to visual images

Question 6

What is the temporal lobe?

Answer 6

Processes auditory info

Emotions

Memories

(It sits below the lateral fissure)

Question 7

What is the limbic lobe?

Answer 7

Curly bit below the cortex that can be seen in a saggital section

Includes the amygdala, hippocampus, mammillary body, and cingulate gyrus

Learning
Memory 
Emotion
Motivation
Reward

Question 8

What is the insular cortex?

Answer 8

Lies deep within the lateral fissure

Visceral sensations
Autonomic control 
Interoception 
Auditory processing 
Visual-vestibular integration

Question 9

What is the internal structure of the cerebral cortex? (What’s it made of)

Answer 9

Grey matter (peel) -
Neuronal cell bodies and glial cells (~85 bil of each) 

White matter -
Myelinated neuronal axons arranged in tracts

Question 10

What are white matter tracts? And what are their types?

Answer 10

They connect cortical areas

Association fibres - connect areas within the same hemisphere

Commissural fibres - connect homologous structures in the left and right hemisphere

Projection fibres - connect cortex with lover brain structures (eg. Thalamus, brain stem, spinal cord)

Question 11

Detail on association fibres? Eg?

Answer 11

Connect ares in the Same hemisphere- never cross to other side

Long fibres - eg. Superior longitudinal fasciculus connects frontal and occipital

Bendy fibres - eg. Uncinate fasciculus connects frontal and temporal lobes

Short fibres

arcuate fasciculus connects wernicke and brocas areas

Look up a photo, very helpful

Question 12

Commissural fibres detail? Eg?

Answer 12

Connect homologous structures in left and right hemisphere

Eg. Corpus callosum and anterior commissure

Question 13

Projection fibres detail? Where do they converge?

Answer 13

Connects cortex with lower brain structures

Afferent - towards cortex

Efferent- away from cortex

Deeper to cortex radiate as the corona radiata

Converge through internal capsule between thalamus and basal ganglia

Question 14

What are the difference between primary and secondary/association cortices?

Answer 14

Primary:

Function predictable

Organised topographically

Left and right symmetry

Eg. Primary somatosensory cortex

Secondary:

Function less predictable

Not organised topographically

Left right symmetry weak/absent

Eg. Language centres - wernicke and broca - only on one side

Question 15

What are the motor areas contained in the frontal lobe?

Answer 15

Primary motor cortex:
Fine, discrete, precise voluntary movement
Provides descending signals to execute movement

Supplementary area:
Involved in planning complex movements (internally cued)
Eg. Speech

Premotor area:
Involved in planning movements (externally clued)
Eg. Seeing an object you want to pick up

Question 16

What are the sensory areas located in the parietal lobe?

Answer 16

Primary somatosensory cortex:
Processes somatic sensation arising from receptors in the body
Eg. Light touch, vibration, proprioception, pain, temp

Somatosensory association area:
Interprets significance of sensory info
Eg. Recognising an object
Awareness of self and personal space

Question 17

What are the visual areas located in the occipital lobe?

Answer 17

Primary visual:
Processes visual stimuli

Visual association:
Gives meaning and interpretation of visual input

Question 18

What are the auditory areas located in the temporal lobe?

Answer 18

Primary auditory:
Processes auditory stimuli

Auditory association:
Gives meaning and interpretation of auditory input

Question 19

Which association areas are concerned with language?

Answer 19

Broca’s area:
Production of language

Wernickes area:
Understanding of language

These are often on the left side of the brain

Also are connected by the arcuate fasciculus

Question 20

What does the prefrontal cortex of the brain do? (Phineas gage)

Answer 20

Attention 
Adjusting social behaviour
Planning
Personality expression
Decision making 

Eg. When this is damaged like in the case of phineas gage it’s like people are no longer themselves at all
Lesions here change personality and lead to inappropriate behaviour

Question 21

What is the result of parietal lobe lesions?

Answer 21

Contralateral neglect

Internal and external

Eg. Lesion in left hemisphere

Lack of awareness of self on right side (might forget to put that arm through a sleeve, or shave that side)

Lack of outside awareness on right side (might only fill half their plate, or only be able to copy the left side of an image)

Question 22

What is the result of temporal lobe lesions?

Answer 22

Leads to agnosia- inability to recognise

Eg. With patient HM, bilateral resection of anterior medial temporal lobe structures to cure epilepsy. Couldn’t form new memories - anterograde amnesia

Question 23

What is the result of lesions in wernicke and Broca’s areas?

Answer 23

Brocas:
Expressive aphasia- poor production of speech. But can comprehend

Wernickes:
Receptive aphasia- poor comprehension of speech. Production is fine

Question 24

What is the result of lesions to the visual areas in the occipital lobe?

Answer 24

Primary visual cortex:
Blindness in the corresponding part of the visual field

Visual association area:
Deficits in interpretation of visual info
Eg. Prosopagnosia- can’t recognise familiar faces or learn new ones

Question 25

How can cortical function be assessed using imaging?

Answer 25

PET - positron emission tomography:
A radioactive marker is attached to glucose, this appears more red in active areas of the brain due to increased blood flow to these areas

fMRI - functional MRI:
Areas in use appear red due to blood oxygen in that brain region

Question 26

How can cortical function be assessed using encephalography?

Answer 26

EEG - electroencephalography:
Measures electrical signals produced by the brain
It’s that funny hat looking thing
Specific places to put each electrode that the technicians work out using percentages of head proportions
Can be used to measure movement of a stimuli along a pathway (eg. Somatosensory) by playing electrodes along that pathway and seeing how the electrodes are sequentially activated

Magnetoencephalography:
Measured magnetic signals produced by brain
Newer

Transcranial magnetic stimulation:
Assess integrity of neural structures
Uses electromagnetic induction to stimulate neurones, this may then produce an (eg. Motor) output

A couple more newer ones, look at session pp