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Pet Scans and fMRIs

It seems that one or both of these is not a picture, but is rather a statistical composite.... which one?That's something I need to look into.

Meanwhile, here's a quote from Wikipedia, the Wild West of learning, about pet scans:
The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Images of tracer concentration in 3-dimensional space within the body are then reconstructed by computer analysis. In modern scanners, this reconstruction is often accomplished with the aid of a CT X-ray scanperformed on the patient during the same session, in the same machine.If the biologically active molecule chosen for PET is FDG, an analogue of glucose, the concentrations of tracer imaged then give tissue metabolic activity, in terms of regional glucose uptake. Although use of this tracer results in the most common type of PET scan, other tracer molecules are used in PET to image the tissue concentration of many other types of molecules of interest
So pet scans indicate glucose consumption. Not STRICTLY speaking a picture of awareness. Rather, at most a picture of something that is concomitant with awarenesss. Consider how the same technique might be used to detect glucose consumption/molecular activity in objects of study other than neurons. It would indicate pretty much the same thing, but no one would identify that with thought.
So it is fine to use a pet scan "image" as an indicator/sign of thought, but not fine to suppose that one is in any sense "looking at thought" when one views a pet scan.
Ditto with fMRI, for that indicates blood flow, which occurs (on a good day) in places other than the brain.

There may be better indicators of cognition. If there is one that is much harder to measure/indicate but much more reasonably identified with cognition itself (I'm granting this here only for the sake of argument), then to identify pet scan/fMRI images with cognition would be like the drunk looking at night for his keys where it was well-lit, because it was easier to see there, when he lost the keys in a place that was poorly lit.

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