Biopsychology - Booklet 3 - Ways of studying the brain Flashcards
What are the four ways of studying the brain?
-Functional magnetic resonance imaging (fMRI)
-Electroencephalogram (EEGs)
-Event-related potentials (ERPs)
-Post - mortem examinations
What is spatial resolution?
-The smallest feature that a scanner can detect, an important feature of brain scanning techniques
What is temporal resolution?
-The accuracy of the scanner in relation of time: how quickly the scanner detects changes
What are the spatial resolutions on the spec?
fMRI = 1-2mm
EEG/ERP = Superficial/General Regions Only
What are the Temporal resolutions on the spec?
fMRI = 1-4 seconds
EEG/ERP = 1-10 ms
What do fMRI measure?
Blood flow in the brain when a person performs a task
How does an fMRI (basically) work?
-Active brain neurons use energy
-Energy requires glucose and oxygen
-Oxgyen released by active neurons, so haemoglobin becomes deoxygenated
-Deoxygenated blood has different magnetic quality
-fMRI detects different magnetic qualities to create 3D activation map
What does an fMRI produce?
A 3 dimensional image called an activation map, showing which parts of the brain are active when doing processes.
What are fMRI’s important for helping us understand?
Localisation of function
What is an example of a use of an fMRI?
People could do a memory task and the fMRI would show which parts of the brain are active/ have a greater blood flow
What are the evaluations of fMRI?
😊It is a safe way of measuring brain activity
😒Can sometimes give inaccurate measures of brain activity
what do EEG scanners measure?
Electrical activity through electrodes attached to the scalp
How do EEGs (basically) work?
-Information is processed in the brain as electrical activity (neurons firing)
-Small electrical charges detected by the electron
-These charges graphed over time, indicating a level of activity
What does Amplitude and Frequency mean in an EEG?
Amplitude - The intensity or size of activity
Frequency - The speed or quantity of activity
What are the two types of EEG patterns produced?
Synchronised - Recognisable waveform (alpha , beta, delta and theta)
Desynchronised - No pattern
What can EEG be used to detect?
Illnesses like epilepsy and sleep disorders, as well as other brain activity diseases.
What are alpha waves and theta/deta waves associated with?
Alpha - Light sleep
Theta/delta - Deep sleep
What are the evaluations of EEGs?
😊A safe way of measuring brain activity
😒Lack of precision when measuring the activity
Why are ERP and EEG similar?
ERP use similar equipment - electrodes attached to the scalp
What happens in an ERG?
-Stimulus presented to participant, researcher looks for activity
-Stimulus is presented many time and an average response graphed
What’s the key difference between EEGs and ERPs?
ERPs record response to a specific presented stimulus, or performance on a specific task
What are researchers able to do with ERPs?
Isolate the brain activity that corresponds to the specific stimulus using statistical averaging
How many times is the stimulus presented in ERP?
Typically about one hundred times, to filter out extraneous brain activity
What are the evaluations of ERPs?
😊A more specific measurement of brain activity than EEGs
😒Not a helpful way of measuring all types of cognitive functions
What are 4 key points to remember about each measurement?
-Function
-Invasive or not
-Causality
-Accuracy
Which is the only invasive measurement?
Post-mortem examinations
What should not be mentioned when talking about post-mortem studies?
Ethics, they’re taken consensually after death
What is post-mortem examination?
Where researchers study the physical brain of a person who displayed a particular behaviour while they were alive
What are two named examples of post-mortem examinations on the spec?
Broca and Wernicke
What was found when Iverson examined the brains of deceased schizophrenic patients?
He found a higher concentration of dopamine, especially in the limbic system, compared to non-schizophrenics
What do Post-Mortem studies allow?
A more detailed examination of anatomical and neurochemical aspects of the brain than would be possible other wise
What are the three main features of a post-mortem examination?
-Looks at anatomy - physical changes
-Looks at neurochemical changes (neurotransmitters)
-After death - no ethics
What do researchers do with brain in a post-mortem?
look at areas of damage in the brain to establish the cause of problems they had, they are also compared to healthy brains to see how they differ
What are the evaluations of post-mortems?
😊Led important discoveries about the brain and particular functions it is linked with
😒Difficult to establish cause and effect
