Biopsych: Ways of investigating the brain

Question 1

fMRI

Answer 1

Identifies which brain areas are active during a task
Measures oxygenated areas of the brain by taking pictures of slices of the brain to create a 3D image
Safe, used for decades with no negative side effects

Question 2

Haemodynamic response

Answer 2

When a neuron becomes more active, oxygen concentration increases there too (the blood vessels widen to accommodate this)

Question 3

Spin

Answer 3

Water molecules (hydrogen atoms) spin upwards because of the magnet and release signals which the scanner picks up

Question 4

Magnetic field disturbances

Answer 4

Sometimes the atoms (and waves) will become displaced due to disturbances
Oxygen atoms help to make the field less easily disturbed

Question 5

fMRI steps

Answer 5

When neuronal activity increases, there is increased blood flow to provide oxygen in that area
The fMRI scanner affects hydrogen atoms in the brain, causing them to spin in the same direction
If there are many active hydrogen atoms (caused by the increase in oxygen) a stronger magnetic signal (magnetic resonance) is sent, which is measured by the fMRI

Question 6

Electroencephalogram (EEG)

Answer 6

Scalp-recorded fluctuation in the brain’s electrical activity
Polarity changes in the neurons in the brain are recorded

Question 7

EEQ equipment

Answer 7

EEG cap, EEG amplifier, data acquisition computer

Question 8

EEG phases

Answer 8

Phase A: prepare the solution - mix distilled water, potassium chloride and baby shampoo together
Phase B: measure the participant’s head - get informed consent, soak cap in solution for 10 mins and find the exact centre of the head
Phase C: lowering impedances and collecting results - place the cap on the participant’s head, with electrode CZ at the centre of the head; lower impedances by wiggling the electrodes and then measure the results

Question 9

Event-related potentials (ERPs)

Answer 9

Taken from EEGs

Question 10

ERP steps

Answer 10

Summates/finds the average background ‘noise’ (extraneous data)
Background brain ‘noise’ is removed
A precise area of brain activity responding to the stimulus is left

Question 11

Post-mortem examination

Answer 11

A surgical analysis of the brain after death
Usually done on people with rare disorders or who have experienced unusual cognitive behaviours or deficits
Can examine areas of damage or structural differences when compared with neurotypical brains
The only technique which can be done on a dead patient