micro mods to neurons

[Craig Hull]

OK, I've been following the dialogue between Ken And Colleen with some 
interest, and have some questions. Exactly what are the physically 
real modifications to the neural circuitry that Ken mentioned happens 
during learning? Are they within the neurons themselves, or between 
synapses? Have the changes been noted with electron microscopy or 
specific markers? And more importantly, if such changes occur, are 
they retricted to neurons within central nervous systems, or can they 
also occur in peripheral sensory neurons? (Any references would be 
appreciated).

Cheers,
Craig.