Fichas
Brain Imaging and Memory
Fichas del conjunto (4)
- 1MEASURING ELECTRICAL ACTIVITY EEG + MEG - postsynaptic potentials - requires thousands of synchronously active cells - activity changes measured in millisecond - good temporal - difficult to localise to brain regions - weak spatial - EEG - measures voltage fluctuations - MEG - measures magnetic fields produced by these currentsMEASURING CORRELATES OF BRAIN ACTIVITY -
PET
- tracks short lived radioactive glucose = produce images of brain activity
- injected into blood
- radiation detectors around head map destination of chemicals in brain
- invasive - 2MRI - standard 3T = 60,000 X earth magnetic field - safe, non invasive, no bio risks - accurate anatomical representation HIGH SPATIAL possible claustraphobiaP SAFETY
anyone near magnet = screened
no metal
ear plugs - 3MRI VS fMRI MRI acquires brain anatomy images - better resolutionfMRI
acquires brain function data
poorer resolution - taking pics of blood flow at time - need to take lots while doing tasks
BOLD signal = indirect measure of neural activity - active neurons shed oxygen and become more magnetic = increase signal - 4IMAGING STUDIES IN MEMORY HM - memory could be impaired selectively WITHOUT loss of other cognitive functions - memory function localised to medial temporal lobes - HIPPOCAMPUS - thought to be a key structure for memory but impairment may be due to combined damage of hippocampus + amygdalaNEUROPSYCHOLOGY (LESION) - attempts to generate a specific brain - behaviour relationship
NEUROIMAGING (fMRI) - takes inverse approach - aims to explore whether experimental manipulation of cognitive function Y necessarily results in attention of brain activity in area X