Dreams, location of?

[Randall Viosca]

This might not be the right group for this, but...

I'm looking for papers or any information about where the brain
 creates/has visual and audio  stimulation/activity during dreaming.

Specifically, what parts along the visual pathway (if any) are
stimulated or active to the point that it might be inferred that those
parts are actively visualizing or creating the image the dreamer is
perceiving?  Is the striate cortex active?  It may seem far fetched,
but has anyone been able to measure retinal activity during dreaming?

Or have dreams been proven to be a more symbolic, higher level
cortical function? 

I am wondering if the circuit could look something vaguely like this
*logical* diagram:

                                    S
                                    W
                                    I (or filter?)
  receptor (environmental) input    T
eyes --------->[LGC]----------->\   C
                                 \  H  
                                  >--->StriateCortex>---+
       Symbolic (Dreaming) input /                      |
      +------------------------>/                       |
      |                                                 |
      |                                                 /
      ^                                                /
      Higher cortical area(s).  <---------------------/ 


And could there be an analogous representation for audio?

I know there is much research underway with PET, MRI and SQID; have
any of these been applied towards dream research?


Thank you,