Ways of investigating the brain ; biopych

How does a fMRI work?

detects the changes in blood oxygenation that occur as a result of neural brain activity

How do we use fMRI to detect activity in the brain

When a part of the brain is more active, it consumes more oxygen, to meet this demand blood flow also increases in that area

How is oxygen carried to the brain

Through hemogloblin in red blood cells

How do we see this happening in the fMRI scan

Produces 3 dimensional images that show which parts of the brain are involved in different mental processes

How do these 3d images benefit our understanding of the brain

It helps us understand what localisation of the brain is

What does the magnetic field do in fMRI

creates a strong magnetic field around the persons head

how does it measure oxygen levels

Measures if blood is oxygen rich (more hemogloblin) or blood is oxygen poor.

strenghs of fMRI's

• virtually risk-free, non invasive

• very high spatial resolution

Weaknesses of fMRI's

• expensive compared to other techniques

• poor temporal resolution

• only measures blood flow not exact activity

How does EEG's work

measures electrical activity within the brain via electrodes

What are the electrodes measuring

brainwave patterns that are generated from the actions of neurons

what are the 4 main eeg waves

alpha, beta , theta, delta

How do they measure this brain activity

Through amplitude (size of activity) and frequency (quantity)

Which wave has the highest frequency

Beta wave

How are EEG's used in the real world

doctors may use them to find unusual patterns of activity, that may suggest epilepsy ect

strengths of EEG's

• Contributed to our understanding of the sleep stages

• cheap to use, can use larger sample sizes

• high temporal resolution

weaknesses of EEG's

• can't detect activity in deeper brain regions

• Doesn't pin point the the exact source of neural activity.

what is an ERP's

similiar equipment to EEG's, but with a stimulus presented to a participant

what are they observing from the EEG

they are observing if EEG waves change in response to the stimulus, this change is the ERP

how many times do they repeat this method

hundreds of times until an average response is aquired, statistical averaging technique.

strengths of ERP's

• more specific to the meausrement of neural processes.

• identified mental health issues such as phobias.

• quantative/objective data

Weaknesses of ERP's

• lack of standardisation in ERP methodology

• cant completely limit extraneous variables.

post mortem examinations

analysing someones brain after death, usually those with an unusual disorder that have experienced deficits in life

what are they examining in the brains

they are examining areas of damage to establish likely cause of affliction

strenghs of post mortem examinations

• vital for providing foundation work for things like brocas area and wernicks area

• helps to improve medical knowledge

weakensses fro post morem examinations

• causation is an issue, areas of damage may be from after death or due to decay

• Raises ethical concerns, may not be able to give informed consent before death due to their mental issues