ways of studying the brain

Question 1

A strength of fMRI is its high spatial resolution

Answer 1

A strength of fMRI is its high spatial resolution which means the activity of the brain is precisely measured to an accuracy of 1-2 millimetres. This is important when identifying
small areas with specific functions such as Broca’s area involved in speech production. It also allows for deep areas of the brain to be investigated, which is useful in memory research focusing on subcortical areas such as the hippocampus. This ultimately means fMRI can measure how brain activity is localised, which is an advantage over an EEG which measures more general activity in superficial cortical areas

Question 2

limitation of fMRI scans is the difficulty of interpreting the data.

Answer 2

limitation of fMRI scans is the difficulty of interpreting the data. Completing a specific cognitive task during an fMRI scan will often simultaneously activate many different areas in the brain. It is therefore challenging to infer cause and effect between the exact involvement of a particular brain region and the function being investigated. Some psychologists also argue that although localised activity is revealed by an fMRI scan, this cannot reveal details
about the communication between different brain areas, which therefore fails to provide a holistic understanding of neural functioning.

Question 3

A strength of an EEG is that they have led to developments in our understanding of regular
brain functions

Answer 3

A strength of an EEG is that they have led to developments in our understanding of regular brain functions and the diagnosis of conditions such as epilepsy and Alzheimer’s. For example, EEG scans have allowed us to gain deeper understanding into the stages of sleep. Dement and Kleitman studied 9 participants who slept for up to 61 nights in a laboratory whilst their brain activity was recorded using an EEG. They found that brain activity changed in sleep cycles throughout an entire sleep period. The participant awakened during REM sleep reported dreams 80-90% of the time, compared to only 7% for NREM sleep. This is a strength
as the use of EEG scans has allowed for strong empirical evidence for the five stages of sleep occurring as part of an ultradian rhythm.

Question 4

limitation of an EEG is the practical issue associated with using the equipment.

Answer 4

Attaching electrodes to the scalp directly or via a skull cap can be uncomfortable for the participant,
which could result in the measurement of brain activity that does not occur whilst a participant is not using the equipment in an everyday environment. The level of discomfort and lack of representativeness is exacerbated by the fact that EEGs are often used to measure general brain states over a period of hours in a clinical setting. This may put off many
participants from taking part in typical research using EEGs and therefore limit population validity because only those willing to undergo such procedures will volunteer

Question 5

strength of using ERPs is their high temporal resolution

Answer 5

strength of using ERPs is their high temporal resolution, which refers to how quickly the scanner can detect changes in brain activity. Neural activity in the brain corresponds to an ERP graph with only a 1-millisecond delay, which is advantageous compared to fMRI that has a delay of 1-4 seconds. Since an ERP directly measures neural activity, it can investigate the
brain where timing is important. Researchers have identified many types of ERP and described the precise roles of these in such as in the measurement of cognitive functions and deficits. An example of this is an ERP which is thought to be involved in the allocation of
attentional resources in working memory. This shows that it is possible to identify brain activity whilst completing specific cognitive tasks

Question 6

limitation of using ERPs is low spatial resolution

Answer 6

limitation of using ERPs is low spatial resolution. Whilst the ERP measures brain activity in response to a specific event, it is unable to identify the specific location of where the brain activity is. This is because each electrode measures the general activity of many thousands of neurons and can only detect the activity in superficial cortical regions of the brain and not
deeper areas. This is unlike fMRI where psychologists can determine the activity of different brain regions with greater accuracy. This suggests that ERP is not an ideal choice when
psychologists are trying to pinpoint specific brain regions performing specific functions.