www.neuron.yale.edu

Hi,
I am trying to use the STDP synapse model, available at:
http://www.neuron.yale.edu/neuron/news/stdp.mod
I can successfully compile it (with mknrndll, under Windows XP, NEURON 5.9.36); however, when I try to load the resulting nrnmech.dll in I get the following error:

loading membrane mechanisms from nrnmech.dll
Undefined symbol _add_nrn_fornetcons referenced from nrnmech.dll

How can I solve this problem? How to refer to _add_nrn_fornetcons?

Thanks in advance,
Filip

Get the most recent version of NEURON. If you already have the most recent
"standard distribution," get the most recent alpha for your particular hardware.
Like all new features that have not yet been extensively used, this may have hidden
bugs, so you should test it to make sure that it works properly.

Hi Ted,
thanks a lot for your reply.
Unfortunately, the STDP synapse doesn't work with the newest alpha version of NEURON (6.0.838; 2007-01-22) neither.
It looks like the problem is with the FOR_NETCONS() function present in the STDP.mod code, but I cannot find this function in the NEURON sources.

Maybe the problem is specific for the Windows distributions only.
I found similar question posted by guillaume (Mon Jun 19, 2006 1:59 pm, Post subject: NET_RECEIVE block for STDP); however, the reply did not actually explain the problem.

Can you suggest anything else?

Thanks a lot,
Filip

[/b]

It works just fine under Linux, but when I tried two different versions of NEURON under
MSWin (5.9.10 which is the current standard distribution, and a 6.0 alpha version) I got
the same error message you saw. I'll let you know when this bug has been fixed.

This alpha version for MSWin
nrn-6.0.alpha-841-setup.exe
handles FOR_NETCONS properly. You can pick it up from the
Snapshots of alpha versions
link on the Download and Install NEURON page
http://www.neuron.yale.edu/neuron/install/install.html

Please note that stdp.mod implements just one of the many possible varieties of spike-
timing-dependent plasticity. Effective synaptic strength is the product of the NetCon's
weight and the factor 1+A, where A is >= 0 and represents the degree of potentiation.
Potentiation is additive and nonsaturating (pre before post adds a positive number to A),
depotentiation is multiplicative (post before pre multiplies A by a factor in the range
0 to 1). With slight modification, other plasticity rules could be implemented, e.g.
saturating or clipping weight changes, multiplicative potentiation, subtractive depotentiation,
"true" synaptic depression (effective weight possibly < NetCon's weight), etc..

Hi Ted,
The STDP.mod is compiled and loaded correctly, now. Thanks a lot!

Filip