Ch 4: How can the brain be mapped Flashcards
CT-scan
Rapid assessment in acute phase
Do not show a clear picture of the different brain structures
–> MRI preferred choice for scientific research
SPECT or PET
radioactive particles
blood flow and metabolism within the brain tissues can be visualised with this
both give an indication of the severity of the trauma
MRI, MEG and EROS
measures changes in blood flow
Structural imaging with a CT-scan
often used for schizophrenia, haemorrhage, space-occupying lesion
Sagittal, coronaal, transversaal
sagittal: from nose to back of head –> 2 hemispheres
coronal: oor tot oor
transversal: from eyes to the other side –> horizontal
Structural imaging with MRI scan
- clear distinction between Gray matter and white matter
- insight into possible abnormalities white matter
- not as harmful as CT
- Sometimes a contrast fluid is used to see brain damage more clearly
Diffusion tensor imaging
- isotropic diffusion
- anisotropic diffusion
utilises the properties of water molecules –> provides information about the direction of the white matter in the brain
isotropic: water molecules move freely in all directions
anisotropic: water molecules are limited in movement
MRS: magnetic resonance spectroscopy
provides information about the concentration of certain molecules, this technique is frequently used to examine a specific location in the brain in detail
Spatial resolution
sharpness of an image
Temporal resolution
the speed of the recordings
Best temporal resolution
EEG
FMRI
PET - MEG
Best spatial resolution
PET
MEG
EEG
fMRI
EEG: electroencephalography
Used most commonly
disadvantages: disruptance of the electric fields by the skull, skin and surrounding tissues
MEG: magnetoencephalography
measures the magnetic field generated by action potentials
not disrupted by tissue or bone –> more precise location of activity
EEG: three type of information
- event-related potential or ERP is the average electrical signal from the tissue closest to the electrode
- fluctuation of the EEG signal is the result of brain waves
- the locations of the areas that respond to a specific task can be determined by the relative strength on each electrode
