Why conversational equations and emergence (General)

by romansh , Friday, April 04, 2014, 02:24 (3885 days ago) @ David Turell
edited by unknown, Friday, April 04, 2014, 03:21


> > Romansh: Over hyped junk? possibly.
> > But unfortunately this does not help your argument one iota David.
> > 
> > That we can get a crude image of vision from a very poor proxy for what our brain actually does. The observation that blood flow gives us information does not somehow diminish because it is measured in the degree of oxygenation in our blood.
> 
> I need to correct your imporession of what FMRI does. It shows intensity of blood flow to a region of the brain, not the oxygenation level of the blood. In a direct sense what you may mean in the level of oxygen demand by a region of the brain.-Does it use the doppler effect to show movement? I don't think so.
What it does is measure the change in the magnetic response in the haem molecules when the central iron atom is oxygented or not. -My guess is the frequency of the magnetic waves is tuned to hydrogen atoms around the porphyrin structure in haem molecule.-I would agree this is used as a proxy for blood flow.