Biopsychology - Ways of studying brain Flashcards
What are the 5 ways of studying the brain?
- EEG (ElectroEncephaloGram)
- ERP (Event Related Potentials)
- Post mortem
- fMRI (functional Magnetic Resonance Imaging)
- PET (Positron Emission Tomography)
What is an EEG?
- Electrical activity (“brain waves”) in the brain are recorded using electrodes placed on the scalp
- The EEG records the electric impulses (action potentials) as neurons fire
- Show patterns of activity which can be used diagnostically in epilepsy or to study mirror neurons or sleep for example
- Each electrode produces its own reading so some vague localisation may be visible
What are examples of EEGs?
Mirror neuron research used to show areas that are active both when doing and watching a task.
This led to the broken mirror theory of autism.
Diagnostic tool in epilepsy treatment + research and sleep research.
What are the strengths of EEGs?
- Measuring electrical activity from the brain is useful because the brain uses electrical impulses to operate.
- Application to diagnosis of epilepsy and studying stages of sleep.
- High temporal resolution (a millisecond).
- Non invasive and risk-free.
What is the weakness of EEGs?
It can identify a general area of activity, but it cannot pinpoint specific areas of neuronal activity, so it may be less useful than other methods.
What is ERP?
- Uses EEG equipment
- ERPs are the measurement of small potential changes in the EEG signal immediately after the presentation of a sensory stimulus (event)
- This makes it possible to record specific brain responses to sensory, motor, cognitive and other mental events
- Show patterns of activity
- These can be linked to specific processes such as attention and perception
What are the strengths of ERPs?
- A form of EEG so shares the positives
- Provide more specific data on neural processes and allow for comparison of different ERPs and EEG.
What is the weakness of ERPs?
Can be difficult to use; background noise and other stimuli must be completely eliminated.
What is post mortem?
- Dissection and examination of the brain after death
- May involve observation of the gross structure of the brain, or the examination of slides of thin slices of the brain for microscope study; this is known as histology
What are the strengths of post mortem?
- Historically very important
- Allows detailed study of structure which may be used to generate hypotheses for further studies on living brains
What are the weaknesses of post mortem?
- Limited as it is structural rather than functional information
- It is impossible to be sure about cause and effect (Broca’s patient Tan may have had speech problems because of a less obvious area of damage)
- Ethics - issue of informed consent obtained from brain damage patients before death eg. HM’s brain was studied in post mortem
What are the examples of post mortem?
HM - thousands of slices were taken from his brain
Kitten’s visual cortex were studied after having one eye sewn shut
Tan - post mortem allowed identification of Broca’s area
What is fMRI?
- Functioning magnetic resonance imaging
- Measures blood flow = more oxygen = more activity in that part of the brain
- Detects radio wave changes
- Measurements are taken as the person performs a certain task, therefore functional
- Allows for study of localisation of function
What are the strengths of fMRI?
- Very high spatial resolution to 3 cubic mm or less, becoming more precise all the time
- Non invasive and virtually risk-free
- Compared to PET, it is safer as it does not use radiation
What are the weaknesses of fMRI?
- The person must remain completely still for accurate results
- Temporal resolution is poor - there is a 5 second time lag between the firing of a neuron and screen image
- Measures blood flow not neuronal activity so exactly what sort of brain activity is represented is hard to know
