Ways of Investigating the Brain

Question 1

fMRI or Functional Magnetic Resonance Imaging

Answer 1

• brain scanning technique
• works by detecting changes in blood oxygenation levels and the flow which occurs as a result of neural activity in certain areas of the brain
• a brain area will consume more oxygen if it is active, so the flow of blood is directed to this area
• this is known as a haemodynamic response
• when oxygenated haemoglobin are without oxygen, they react differently, which is picked up by the scanner
• the fMRIs produce 3D images or activation maps, showing the parts of the brain involved in specific mental processes

Question 2

(+) EVAL - fMRI

Answer 2

• fMRI doesn’t rely on radiation like other techniques e.g. PET scans
• if done correctly it is effectively risk-free
• it is also easy to use and non-invasive
• fMRI images have a very high spatial resolution, detail being presented in the millimetres
• clear picture of how brain activity is localised is presented by an fMRI

Question 3

(-) EVAL - fMRI

Answer 3

• fMRI is comparatively quite expensive
• only able to capture a clear image if the individual holds perfectly still
• there is a 5 second time leg between when the initial firing of neuronal activity takes place and then appears on the screen, which means that the temporal resolution is not very good
• only blood flow in the brain can be measured by fMRI, which means that it can’t target the activity of single neurons, and therefore it can be difficult to tell what type of brain activity is being shown

Question 4

EEG or Electroencephalogram

Answer 4

• measure electrical activity in brain using electrodes attached to a person’s head with a skull cap
• shows brainwave patters generated from millions of neurons acting at the same time and giving an overview of brain activity
• used typically as a diagnosis tool by clinicians since arrhythmic (irregular) brain activity patterns may be linked to neurological abnormalities, such as epilepsy

Question 5

(+) EVAL - EEG

Answer 5

• invaluable to diagnosis for conditions such as epilepsy
• random bursts of activity in the brain which characterise the disorder are easily detectable with an EEG
• extremely high temporal resolution
• brain activity be detected at a resolution of one millisecond

Question 6

(-) EVAL - EEG

Answer 6

• info which is received by the EEG is generalised, which is a major drawback
• not useful for trying to pinpointing an exact neural activity source
• doesn’t allow researchers to discern between activities coming from different but adjacent locations

Question 7

ERPs or Event-Related Potentials

Answer 7

• EEGs have a number of scientific applications but can give crude, overly generalised measures of brain activity in raw form
• EEGs are useful to cognitive neuroscientists since the data holds all the neural responses linked to specific sensory, motor and cognitive events
• researchers have developed a way of acquiring and singling our responses
• using statistical averaging techniques, any extraneous brain activity is filtered our and what we are left with are ERPs
• they are types of brainwaves triggered by certain events

Question 8

(+) EVAL - ERPs

Answer 8

• the limitations of EEGs are solved by ERPs
• they bring greater specificity to the measurement of neural processes
• very food temporal resolution, which means that they can be used widely in measurement of cognitive deficits and functions

Question 9

(-) EVAL - ERPs

Answer 9

• lack of standardisation in the methodology between studies makes it difficult to confirm any findings
• for pure data from ERPs to be established, their must be absolutely no background noise or extraneous materials, which isn’t an easy feat

Question 10

Post-mortem examinations

Answer 10

• analysis of a person’s brain after they have died
• typically performed on individuals with rare disorders or having experienced deficits in mental process or behaviour
• damaged brain areas are examined in order to establish the most likely cause of the disorder
• brain may be compared with a control/neurotypical

Question 11

(+) EVAL - post-mortem examinations

Answer 11

• post-mortem exams were vital in establishing early foundations of understanding of key brain processes
• Broca and Wernicke relied on post-mortems to study the brain and link it with language and behaviour, prior to the introduction of neuroimaging
• hypothesis for study and medical knowledge have been improved by post-mortem studies

Question 12

(-) EVAL - post-mortem examinations

Answer 12

• causation is an issue with these studies
• brain damage might not be associated with deficiencies but rather another trauma or decay which is unrelated
• these studies also raise ethical issues surrounding consent from the parent prior to their death
• informed consent from the patient of post-mortem examination is impossible to get