L33 Psych 3604 Lecture Notes - Lecture 3: Diamagnetism, Voxel, Block Design
Document Summary
Magnetic resonance imaging (mri: relies o(cid:374) (cid:373)ag(cid:374)ets (cid:894)~60,000(cid:454) stro(cid:374)ger tha(cid:374) earth"s (cid:373)ag(cid:374)etic field(cid:895, non-invasive (subjects only exposed to magnetic field and radio waves, high spatial and temporal resolution, shows brain structure. Diffusion tensor imaging (dti: reveals fiber orientations in white matter tracts (axons, water diffuses most easily along length of axons, color coding shows dominant diffusion orientation. Positron emission tomography (pet: uses a radioactive tracer injected into the bloodstream increase in neural activity leads to increase metabolism, which leads to increase blood flow. Oxygen 15 is no longer used much: tracers can also label chemicals, ex: neurotransmitters (dopamine, lack of structure in pet scans, pet is good for studying. Slower temporal resolution (tracer needs to wash out btw experimental conditions) Functional magnetic resonance imaging (fmri: non invasive, but expensive. When neurons fire, they require additional oxygen. Bold relies on the different magnetic properties of oxygenated and deoxygenated blood.
