ways of studying the brain Flashcards
what is temporal resolution?
-the accuracy of the scanner in relation to time
-how quickly the scanner can detect changes in brain activity
what is spatial resolution?
-the smallest feature or measurement that a scanner can detect
what does fMRI stand for?
functional MRI/ functional magnetic resonance imaging
how does an fMRI work?
-measures blood flow in the brain while a person performs a task
-Neurons in the brain that are the most active use the most energy, which requires glucose and oxygen.
-Oxygen is released for use by these active neurons at which point the haemoglobin becomes deoxygenated.
-Deoxygenated haemoglobin has a different magnetic quality from
oxygenated haemoglobin- an fMRI can detect these different magnetic qualities to create a dynamic 3D map of the brain.
what is the end product of an fMRI/ what does it create?
-a dynamic 3D map of the brain
what does eeg stand for?
Electroencephalogram
how does an EEG work?
-measure electrical activity through electrodes attached to the scalp
-Information is processed in the brain as electrical activity in the form of action potentials or nerve impulses.
-Small electrical charges are detected by the electrodes and graphed over a period of time, indicating the level of activity.
How many different types of EEG patterns are there? What are they?
-4
-Alpha, Beta, Theta, Delta
what is the end product of an EEG/ what does it create?
-There are 4 types of EEG patterns: alpha, beta, theta and delta waves.
-EEG patterns produce two distinctive states: synchronized patterns (a recognizable waveform such as alpha, beta, delta and gamma) and desynchronized patterns (no pattern).
what does ERP stand for?
Event Related Potential
how does an ERP work?
-use similar equipment to EEGs (electrodes attached to the scalp)
-a stimulus is presented to a participant (for example a picture or sound) and the researcher looks for activity related to that stimulus.
-‘Averaging’ is used- the stimulus is presented multiple times (usually hundreds), and an average
response is graphed. The time/ interval between the presentation of the stimulus and the response is
referred to as latency.
what is the end product of an ERP/ what does it create?
A graph of average responses to the stimulus
True or False? For an ERP, a stimulus is presented 3 times and the average is graphed.
False! The stimulus is presented LOADS, maybe even hundreds of times!
What are the temporal and spatial resolutions of an ERP?
-Temporal Resolution: EEGs show activity every millisecond, recording activity in nearly real time
-Spatial Resolution: EEGs only detect activity in superficial, general areas of the brain.
What are the temporal and spatial resolutions of an EEG?
-Temporal Resolution: EEGs show activity every millisecond, recording activity in nearly real time
-Spatial Resolution: EEGs only detect activity in superficial, general areas of the brain.
What are the temporal and spatial resolutions of an fMRI?
-Temporal Resolution: images show activity up to 5 second after it occurs
-Spatial Resolution: thought to be accurate within 1-2mm
What is a Post-Mortem?
-Researchers study the physical brain of a person who displayed a particular behaviour while they were alive
What are the ways of studying the brain?
-fMRI
-EEG
-ERP
-Post Mortem
How many ways are there to study the brain?
4
What are the strengths of fMRIs?
-good spatial resolution
-non invasive
What are the strengths of EEGs?
-good temporal resolution
-non invasive
What are the strengths of ERPs?
-good temporal resolution
-non invasive
What are the strengths of Post-Mortems?
-Allow for a more detailed examination of anatomical and neurochemical aspects of the brain than would be possible with other techniques
-Have contributed to our understanding of many disorders, such as Iverson + schizophrenia
-Allow for an understanding of the anatomy of the brain, and even now give us a more detailed examination of anatomical and neurochemical aspects than would be possible with other techniques
What are the limitations of fMRIs?
-poor temporal resolution
-cannot show causation
What are the limitations of EEGs?
-poor spatial resolution
-inability to show causation
What are the limitations of ERPs?
-poor spatial resolution
-inability to show causation
What are the limitations of Post-Mortems?
-ethical issues
Explain the strength of post-mortems that they have contributed to our understanding of many disorders?
-Iverson examined the brains of deceased schizophrenic patients and found a higher concentration of
dopamine, especially in the limbic system, compared to non-
schizophrenics. This allowed psychologists to understand the
disorder more, and helped develop the treatment of it.
-Broca’s post-mortem study of his patient ‘Tan’, where he found a lesion in the area of the brain now called ‘Broca’s Area’, that he came to understand was responsible for speech-production.
-This is a strength as it shows the value post-mortems have had in understanding howe the brain and particular disorders work.
Explain the limitation that they are unable to show cause and effect?
-fMRI scans do not provide a direct measure of neural activity- they
simply measure changes in blood flow; therefore, it is impossible to
infer causation at a neural level.
-EEGs often detect electrical activity in several regions of the brain simultaneously, limiting them.
-This means that psychologists are unable to conclude whether particular brain regions are associated with specific functions (in the case of fMRI) and which area/region the electrical
activity took place (in the case of EEG), making solid cause and effect conclusions impossible.
