text: I highly recommend this site (formerly called fMRI for dummies, lol!)\nhttp://psychology.uwo.ca/culhamlab/Jody_web/fmri4newbies.htm\n\nIt's a really really good site, with tonnes of illustrated diagrams and information on all asects of fmri (and mri). Here's a direct link to a pdf file of the basis of fmri and mri\n\nhttp://psychology.uwo.ca/culhamlab/Jody_web/fMRI4Dummies/pdfs_and_ppt/Basic_MR_Physics_grey.pdf\n\nHope that helps!