Ways of studying the brain Flashcards
What are the 4 main ways of studying the brain?
- Functional magentic resonance imaging (fMRI)
- Electroencephalogram (EEG)
- Event-related potentials (ERP)
- Post-mortem examinations
What is the purpose of scanning techniques?
To investigate localisation
What are fMRIs?
Method to measure brain activity while a person performs a task
How do fMRIs work?
- Detects change in blood flow and oxygenation occuring as a result of neural activity in specific parts of the brain
- Active brain areas consume more oxygen to meet increased demand so blood flow directed to active area (harmodynamic response)
- Produces 3D images (activation maps) showing which parts of the brain are involved in particular mental processes
What are EEGs?
Record of tiny electrical impulses produced by the brain’s activity
How do EEGs work?
- Measures electrical activity in the brain via electrodes (fixed to the scalp using a skull cap)
- Scan recordings represent brainwave patterns generated from thousands of neuron actions
What are EEGs used for?
Used by clinicians as a diagnostic tool: unusual arrythmic patterns of activity may indicate neurological abnormality (epilepsy)
What are ERPs?
The electrophysiological responses of the brain to a specific sensory, cognitive or motor event, can be isolated through statistical analysis of EEG data
How do ERPs work?
- Neural responses which are associated with sensory, cognitive and motor events, are contained within ERP data
- Use of statistical avergaing techniques allow extraneous brain activity from EEG recordings to be filtered out, leaving only responses relating to presentation of a specific stimulus/performance of a specific task
What are post-mortem examinations?
Analysis of the brain after death to determine whether certain observed behaviours during a person’s lifetime can be linked to structural abnormalities in the brain
How do post-mortem examinations work?
- Analyses the brain after death
- Individuals who receive post mortems often have rare disorders or unusual cognitive deficits
- Areas of damage are analysed, establishing cause of affliction
- May involve comparison with neurotypical brain to ascertain extent of the difference
Strengths of fMRIs
- Doesn’t rely on use of radiation
- Virtually risk-free, non-invasive and straightforward
- Images produced have very high spatial resolution- provide clear picture of localisation and brain activity
Limitations of fMRIs
- Expensive
- Poor temporal resolution so not fully representative of moment to moment activity
Strengths of EEGs
- Useful in studying sleep stages and diagnoses
- Useaful in diagnosing epilepsy (bursts of brain activity)
- Extremely high temporal resolution
- Accurately detects brain activity at resolution of one millisecond
- Real world value
Limitations of EEGs
- Information received has been generalised
- EEG signal is not useful for pinpointing the extact source of neural activity
- Does not allow to distinguish between activities originating in different but adjacent locations
