ways of studying the brain

What are the 4 ways of studying the brain

• fMRI

• EEG

• ERP

• Postmortem

fMRI

• detects change in the levels of blood oxygenation

• Uses magnetic fields and radio waves t create 3D images to show which mental processes are present during different activities

Strengths of fMRI

• les invasive as they don’t require radiation or require instruments to be inserted into the brain, however they wouldn’t be suitable for people with metal implants due to the magnetic field

• Excellent spatial resolution (1-2mm) this allows them to identify specific brain regions and what they affect/control

Limitations of fMRI

• relatively poor temporal resolution (1-4s) which means we are unable to detect exact timing of neural activity

• Very expensive

• Can be difficult to interpret a you have to compare them with a baseline and different baseline tasks can lead to different patterns of activation

What does EEG stand for

Electroenephalogram

EEG

• Measure electrical activity using electrodes attached o a patients scalp

• Detect electricity by groups of neurons directly underneath them

• Can detect Alzheimer’s and epilepsy

ERP

• Measure the brains electrical activity in response to an event e.g. a picture or a sound

• They then use statistical averaging to filter out background activity so they only have the activity hat is related to the stimulus

What does ERP stand for

Event related potentials

Strengths of EEG and ERP

• less invasive techniques than things like PET scans, they don’t use radiation and don’t require instruments to be inserted into the brain, virtually risk free

• They have excellent temporal resolution as they record brain activity on a milliesecond by milliesecond basis

• Cheaper than fMRI

• They helped understand cognitive processes as we can see the sequence of mental processes involved in recognition, language comprehension etc

Limitations of EEG’s and ERP’s

• relatively poor spatial resolution as we only see if on the scalp and struggle to identify the exact region it originated in

• Limited when investigating much deeper regions of the brain such as the hippocampus and can’t provide any where near as much detail as an fMRI

Postmortem

• analysing a persons brain following their death

• Typically people with unusual cognitive deficits or rare neurological disorders

• If we can find abnormalities in the brain we may be able to link this to their behaviour when they were alive

• Broca’s postmortem on patient tan helped identify the role of speech production

Postmortem strengths

• detailed examinations of brain structures which can’t be easily investigated using other techniques

• Helped with important discoveries in regions of the brain and what they do, allowing us to understand the relationship between the brain and behaviour

Postmortem limitations

• ethical issues surrounding informed consent, many people may not have given permission when they were alive or may not have the mental capacity to capacity to do so

• We can’t be certain that the abnormalities we find in the brain can be linked to the behaviours we saw in the person when they were alive

• Changes may occur in the brain after death e.g. due to lack of oxygen reducing the validity of the conclusions drawn