Methods for investigating brain function Flashcards
What does EEG stand for?
Electroencephalograph
What does CT stand for?
computed tomography
What does CAT stand for?
computerised axial tomography
What does MRI stand for?
magnetic resonance imaging
What does fMRI stand for?
functional magnetic resonance imaging
What does PET stand for?
positron emission tomography
Measurement type of EEG
External recording
Does not use imaging techniques
Measurement type of CT or CAT
Static imaging, i.e. producing still pictures
Measurement type of MRI
Static imaging, i.e. producing still pictures
Measurement type of fMRI?
Dynamic imaging
Produces colour images of brain structure, activity and function
What type of image is PET scan?
Dynamic imaging
Produces colour images of brain structure, activity and function
Method for EEG
Electrodes on scalp detect & amplify electrical activity in brain
Recorded as series of peaks and troughs on chart
Method for CT/CAT
X-Ray scans brain at different angles
Info sent to computer, leading to cross-sectional pictures of ‘slices’ through brain
Method for MRI
Uses strong magnetic field, radiofrequency pulses, computers to produce 3D images from which 2D slices can be displayed
Method for fMRI
Most recent form of MRI. Measures brain activity based on neuron’s oxygen consumption
Increased oxygen = increased activity, shown in colour variations
Method for PET
Scans provide images of brain by tracking glucose solution containing short lived radioactive tracker
Based on glucose consumption in brain, indicated by colour variations
Use of CT/CAT
Aid in detection of tumours, strokes, other injuries
Can help finding out reasons in things like changed behaviour and personality
Can detect areas of brain that may have shrunk (atrophied) due to e.g. Alzheimer’s disease
Limitation/s of CT/CAT
Images only show brain structure
Images of inferior quality to those from MRI
Use/s of EEG
Investigates activity in whole brain
Has been used to study different states of consciousness e.g. awake, sleeping, dreaming
Different patterns can also indicate epilepsy tumours
Limitation/s of EEG
Doesn’t produce images and cannot detect info from deep in brain
Not good at pinpointing area of brain that is source of brainwave activity
Use/s of MRI
Used in detection of tumours and other abnormalities
Limitation/s of MRI
Cannot be used if patient’s body contains magnetic objects (e.g. pacemakers)
Use/s of fMRI
Enables observation and measurement of changes in brain during activity
Scans can be made rapidly
Good spatial resolution and are non-invasive, do not expose patient to radioactive tracers
Less expensive than PET
Use/s of PET
Used in research to show specific brain areas activated during activities such as reading, speaking, thinking
Does not provide image of health level of brain, but problems (e.g. epilepsy, blood clots, can be identified by comparing to brains of healthy people)
Limitation/s of PET
Not as detailed as those from fMRI
More expensive than fMRI
