Studying the Brain Flashcards
What are fMRI scans?
Functional magnetic resonance imaging, strong magnet which measures changes in blood flow whilst a person performs a task
How do fMRI scans work?
- increased demand for oxygen when an area becomes active
- oxygenated and deoxygenated haemoglobin have different magnetic qualities detected by fMRI scans
- from these researchers can produce 3d scans of the brain
Give advantages of fMRI scans
~ high spatial resolution - accurate to 1-2mm, provides a clear image of localised functions so psychologists can accurately distinguish between brain regions
~ helps us to make inferences about brain function and lateralisation if we look at areas active during certain tasks
~ non-invasive - does not use radiation unlike PET scans making it safer; patients are more likely to use MRI scans and expand knowledge on brain function
Give disadvantages of fMRI scans
~ poor temporal resolution - 5 second delay between neuronal activity and produced image
~ expensive as it requires special equipment and trained experts
~ indirect measures - we cannot be sure changes in blood flow are a result of neuronal activity, no causation
What are ERPs?
Event related potentials; measures brain’s electrophysiological response to a stimulus with electrodes attached to the scalp
How do ERPs work?
Scanners measure electrical activity in the brain through electrodes attached to the scalp; short segments of EEG data time locked to a specific event
Give advantages of ERP
~ non invasive as doesn’t use radiation or involve inserting objects into brain
~ cheap so more readily available, allows more patients to undertake ERPs and expand our knowledge
~ good temporal resolution - takes readings every millisecond so records activity in real time
Give disadvantages of ERP
~ Poor spatial resolution —> only detects activity on superficial regions of the brain; cannot provide info on deeper regions, limiting its use
~ Discomfort for patient as electrodes are attached to the scalp, may result in unrepresentative readings as patients discomfort may affect cognitive response
What are EEGs?
Electroencephalogram, records brain activity with electrodes placed on the scalp which detect electrical changes
Give strengths of EEGs
~ Can be used to diagnose conditions such as Alzheimer’s or epilepsy, giving it practical application
~ Non-invasive as does not use radiation
Give weaknesses of EEGs
~ Poor spatial resolution
~ Detects activity in several regions of the brain simultaneously, making it difficult for researchers to draw accurate conclusions
What is a post-mortem?
Involves researcher studying physical brain of a person who displayed a particular behaviour whilst alive suggesting brain damage
Give strengths of post-mortem
No ethical issues so enables researchers to study the brain without inflicting any harm
Confirm diagnosis suspected such as Alzheimer’s which can only be conclusively decided post-mortem
Give limitations of post-mortem
Comparisons are difficult to draw from a post mortel and a living brain
Cannot measure function as brain is no longer active
