PET Disadvantages

Early brain imaging studies of musical imagery used PET (positron emission tomogra- phy), which has now been almost completely replaced by fMRI. PET and fMRI each have their pros and cons as methods for functional brain imaging. PET works by com- bining several tricks. Typically, subjects are injected with 2-deoxyglucose, a modified form of sugar that is transported through the bloodstream to cells just like glucose, but cannot be metabolized. As a result, 2-deoxyglucose builds up rapidly in highly active cells. By using radiolabeled 2-deoxyglucose, in which one of the hydrogens is replaced with a radioactive element like fluorine, the molecule can be detected because it emits gamma rays. By using gamma ray cameras outside the body, much like a CAT scan, highly active regions of the brain can be detected and imaged. Disadvantages to PET imaging are that it’s relatively slow, and requires injection of a radioactive compound into the bloodstream — which is safe, but understandably a source of concern for many subjects. fMRI avoids these problems, but measures blood flow rather than actual neu-
Earworms and Imagery 8 ronal metabolism, so it is more distantly related to …show more content…
Others have argued that there is a distinction between subvocalization (our inner voice) and the phonological store (our inner ear). In this view, subvocalization is more of a motor plan, whereas the phonological store is a short term acoustic memory. The idea is that these two compo- nents are tightly linked and work together during auditory imagery. Based on the neu- roimaging data we have seen so far, it’s tempting to speculate that the SMA could be involved with subvocalization, whereas secondary auditory cortical areas could be in- volved with the phonological