Is this stuff really taught in churches?

"My understanding was that it's possible to measure activity, not as blood blood flow but as actual neuronal activity (like measuring theta waves in Buddhist monks). You can measure an intensity and then, based on the regions of the brain that are active, you have some idea what kind of emotional response it was."

You can measure individual cell activity (firing), but you can't measure all of the cells at once. There's too many of them.
With PET scanning, you are measuring activity, but you do so by measuring the blood flows in the brain. By using an slightly radioactive isotope that decays quickly, you can map out what parts of the brain are most active for a short period of time. The active parts of the brain use much more blood than the inactive parts, and this is what you are measuring. You inject the solution, while simultaneously illiciting the activity you wish to "map", and turning on the machine for about 10 seconds. You do this about 5 times, while also mixing in about 5 baseline scans where no stimuli is given. Then you subtract the images to give you the "change" in blood flow for that given stimuli.

"My understanding is that the brain doesn't differentiate between memory and current events. "

Sure it does. Memory recall is different than current memory formation. Also, there is more than one way the brain can set something in memory as well as pull an old memory up. You're frontal cortex knows if it is pulling the memory from the temporal lobe or if it is reacting to new stimuli.

 

<div class='quotetop'>QUOTE(Darwood @ Nov 29 2007, 09:40 AM) [snapback]545633[/snapback]</div>

Actually, it's fMRI that measures activity by blood flow changes. PET (with FDG) uses glucose uptake (or, with rarer isotopes, oxygen utilization, and something we're working towards with radiopharmacology is tracers that bind to specific receptors)... There's also MEG (magnetoencephalography) which I didn't see mentioned yet. It's similar to EEG in that it can measure the electrical activity of a large group of neurons, but isn't as limited to the surface of the cortex as EEG is. It's a lot more resource intensive though!

 

wow, you clinical folks inspire me

i don't know how well i'd like a radioactive tracer in my brain... not so much even for the radioactivity (said the girl who gets more irritated with the associated paperwork than the actual chemical use) but the receptor activity leading to altering of signaling! i suppose a partial agonist would be the most safe route to go but even that kinda worries me.

we have plenty of radioactive tracer research in fixed brains, but i do wonder about a dynamic system and how that would interfere.