retrograde messengers?

Rogene Eichler Pharm-NeuroSci rogene at lenti.med.umn.edu
Wed Apr 7 18:36:48 EST 1993


In article <1993Apr3.032038.14001 at Princeton.EDU> gsanders at atbat.Princeton.EDU (Gillian Denise Sanders) writes:
>Hi. I am currently working on my undergraduate thesis on neural networks and  
>mathematical models. I have been using the backpropagation algorithm and have  
>noticed several references to its biological impausibility as one main  
>disadvatage. I am taking a brain course and our professor mentioned retrograde  
>messengers , nitric oxide and"back talking" in methods of learning such as  
>classicalical conditioning. To me this would seem to suggest that perhaps the  
>backpropagation method is not entirely biologically implausible...does anyone  
>have any information about this topic or else any references to papers which  
>discuss retrograde messengers and its backward synaptic directions? Thanks in  
>advance. Gillian Sanders

Backprop involves an external *teacher*, whereas the weight change via
Nitric Oxide is a local phenomena more akin to a Hebbian type network.
Perhaps a more plausible backprop analogy might be found in the cerebellum
where an error signal is thought to originate from the climbing fibers
(inferior olivary nucleus). 

1
UI  - 93042981
AU  - Chapman PF;Atkins CM;Allen MT;Haley JE;Steinmetz JE;
TI  - Inhibition of nitric oxide synthesis impairs two different forms of
      learning.
SO  - Neuroreport 1992 Jul;3(7):567-70

2
UI  - 92153413
AU  - Haley JE;Wilcox GL;Chapman PF;
TI  - The role of nitric oxide in hippocampal long-term potentiation.
SO  - Neuron 1992 Feb;8(2):211-6
      NEURON


I don't read the newsgroups too often, so if you would like to discuss
this further, please send e-mail!

						Cheers!


							-Rogene

 
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			Rogene M. Eichler West

 Neuroscience Program                  Minnesota Supercomputer Institute
University of Minnesota         Army High Performance Computing Research Center

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