Biopsychology - Ways of studying the brain

Question 1

Describe fMRI

Answer 1

• fMRI measures blood flow in the brain when a person performs a task.
• Neurons in the brain that are the most active use the most energy.
• When oxygen is used, haemoglobin is deoxygenated. Deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin and this can be detected by an fMRI machine.

Question 2

Temporal resolution of fMRI

Answer 2

Show activity 1-4 seconds after it occurs

Question 3

Spatial resolution of fMRI

Answer 3

Accurate within 1-2mm

Question 4

Describe EEG

Answer 4

EEG scanners measure electrical activity through electrodes attached to the scalp.
Electrical changes detected and graphed over period of time.

Question 5

What can EEGs be used for?

Answer 5

Diagnosing epilepsy, sleep disorders etc

Question 6

Describe ERP

Answer 6

ERP uses similar equipment to EEG (electrodes attached to the scalp).
A stimulus is presented to a participant e.g. a sound and the researcher looks for activity related to that stimulus.

Question 7

Describe post-mortem

Answer 7

Studying the brain of a person who displayed a particular behaviour when they were alive.

Allows more detailed examination of anatomical aspects of the brain than possible with other techniques.

Question 8

Evaluation of fMRI

Answer 8

• Poor temporal resolution (how quickly
  the scanner can detect changes in brain activity), so consequently,
  psychologists are unable to predict with a high degree of accuracy the onset of
  brain activity.
• An advantage of fMRI is that is non-invasive. Unlike other scanning techniques e.g. PET, fMRI does not use radiation or involve inserting instruments directly into the brain, and is therefore virtually risk-free. Consequently, this should allow more
  patients/participants to undertake fMRI scans which could help psychologists to
  gather further data on the functioning human brain and therefore develop our
  understanding of localisation of function.

Question 9

Evaluate EEG/ERP

Answer 9

An advantage of EEG and ERP is that both techniques are
non-invasive. Unlike other scanning techniques, such as Positron Emission
Tomography (PET), EEG and ERP do not use radiation or involve inserting
instruments directly into the brain and are therefore virtually risk-free.
Furthermore, EEG and ERP are much cheaper techniques in comparison with fMRI
scanning and are therefore more readily available. Consequently, this should allow
more patients/participants to undertake EEG/ERPs, which could help psychologists
to gather further data on the functioning human brain and therefore develop our
understanding of different psychological phenomena, such as sleeping, and
different disorders like Alzheimer’s.

One disadvantage of EEG/ERP is that these
techniques have poor spatial resolution. Spatial resolution refers to the smallest
feature (or measurement) that a scanner can detect, and is an important feature of
brain scanning techniques. Greater spatial resolution allows psychologists to
discriminate between different brain regions with greater accuracy. EEGs/ERPs
only detect the activity in superficial regions of the brain. Consequently, EEGs and
ERPs are unable to provide information on what is happening in the deeper regions
of the brain (such as the hypothalamus), making this technique limited in
comparison to the fMRI, which has a spatial resolution of 1-2mm.

Question 10

Difference between EEGs and ERPs

Answer 10

ERPs enable the determination of how processing is affected by
a specific experimental manipulation. This makes ERP use a more
experimentally robust method as it can eliminate extraneous neutral activity,
something that other scanning techniques (and EEG) may struggle to do.

Question 11

Evaluate post-mortem

Answer 11

One of the main limitations of post-mortem examination is the issue of
causation. The deficit a patient displays during their lifetime (e.g. an inability to
speak) may not be linked to the deficits found in the brain (e.g. a damaged Broca’s
area). The deficits reported could have been the result of another illness, and
therefore psychologists are unable to conclude that the deficit is caused by the
damage found in the brain.

However, one strength of post-mortem examinations is that they provide a
detailed examination of the anatomical structure and neurochemical aspects of
the brain that is not possible with other scanning techniques (e.g. EEG, ERP and
fMRI). Post-mortem examinations can access areas like the hypothalamus and
hippocampus, which other scanning techniques cannot.