Cerebral cortex

Question 1

What are the three types of cerebral white matter?

Answer 1

Association fibres - connect areas within the same hemisphere
Commissural fibres - corpus callosum. Connect the left and right hemisphere together
Projection fibres -corticospinal tract. Connect the cortex with lower brain structures

Question 2

How many layers is the cortex made up of?

Answer 2

6

1-3 mainly cortico-cortical connections - association fibres
4 input from thalamus
5-6 connections with subcortical, brain stem and spinal cord - projection neurones

Question 3

Describe the structure of the organisation of the neocortex.

Answer 3

Columnar arrangement and layers (lamina structure)

There are more densely packed vertical connections- basis for topographical organisation
Neurones with similar properties are connected in the same column

Question 4

What lobes make up the neocortex?

Answer 4

Frontal, Parietal, Temporal, occipital. The frontal and parietal lobes are separated by the central sulcus.

The central sulcus runs form the longitudinal fissure to the lateral slyvian fissure (lateral sulcus).

Question 5

Where does all taste sensation go?

Answer 5

It goes to a single nucleus in the brain stem called the nucleus solitarious in the medulla oblongata.

Question 6

Define the inability to recognise faces?

Answer 6

Prosopagnosia - lesion of the visual posterior association area (fusiform gyrus)

Question 7

What happens when you get a frontal lobe lesion?

Answer 7

Characterised by lack of planning, behaviour becomes disorganised, attention span and concentration diminish, self-control is hugely impaired

Overall social behaviour

Question 8

What happens when you get a parietal lobe lesion?

Answer 8

Parietal cortex lesions - learned procedures
The posterior parietal association of the cortex creates a spatial map of the body in surroundings, from multi-modality information.

• Dyspraxia or Apraxia, inability to read maps or understand spatial information, hemispatial neglect (drawing half a house/clock). Inability to carry out programmed movements
• Hemispatial neglect: half of the visual field is gone

Question 9

What happens when you get temporal cortex lesions?

Answer 9

Temporal lobe is involved in language, object recognition, memory and emotion.
Injury leads to agnosia receptive aphasia
No hippocampus function - particularly involved in memory.

Question 10

Define hemispheric specilizaiton

Answer 10

Refers to the different and specific functions performed by the two hemispheres of the brain. … For example, language skills are primarily located in the left hemisphere while spatial reasoning and mechanical skills are associated with the right.

Question 11

Define TMS?

Answer 11

Transcranial magnetic Stimulation

○ Induces a current in the cortex
○ Test for function of a specific area
○ Can make neurons fire or stop them

Question 12

Define TDCS

Answer 12

Transcranial direct current stimulation

○ 2 electrodes on the head
○ Increases or decreases the firing rate of neurons

Question 13

Define PET

Answer 13

Positron Emission Tomography

○ Radioactive tracer in the brain
○ Can show functional changes
○ In Parkinson’s there is less F-DOPA uptake
○ SPECT = lower resolution of PET

Question 14

Define MEG and EEG?

Answer 14

Magnetoencephalography - Measures magnetic fields

Electroencephalography - Measures electric fields

Question 15

Define fMRI?

Answer 15

Functional magnetic resonance imaging - detects changes associated with blood flow