STDP using FOR_NETCONS

[srikanth_rswamy]

Hi

I'm looking at incorporating STDP in a model of the neocortical column, and came across Michael Hines's code for the same.

I'm rather curious to know what the FOR_NETCONS keyword does precisely. However, I could not find any documentation explaining the same in greater detail.

Another thing that is not very clear to me is the 'flag' that is used in the code. The very first instance of this flag appears only in the NET_RECEIVE block. Does this flag receive information on the timing of the pre-synaptic cell ?

There's also a WATCH keyword towards the end of the code. Does this keep track of some kind of a spiking threshold to see if a postsynapticcell fired or not? Say, if the voltage crosses -20 mV , then perhaps it is an indication that the postsynaptic cell fired.

I would be happy to receive some more documentation about FOR_NETCONS and these flags in the code, or alternatively a pointer to an URL with some material.

Cheers
Srikanth

[ted]

FOR_NETCONS was introduced earlier this year. Google search from NEURON's home
page generates several hits, including this one which is most informative:
What's new?
extends the NET_RECEIVE block by introducing the FOR_NETCONS statement. ie FOR_NETCONS(same, args, as, netreceive) { stmt } which iterates over all NetCon ...
www.neuron.yale.edu/neuron/news/news_2_23_06.html

flag allows a mechanism to distinguish self events from input events (events from other
sources). Self events can also specify a particular value for flag that can be used to serve
various purposes. See chapter 10 of The NEURON Book or
Hines, M.L. and Carnevale, N.T.
Discrete event simulation in the NEURON environment.
Neurocomputing 58-60:1117-1122, 2004.
(preprint available from https://neuron.yale.edu/neuron/publications/biblio)

WATCH specifies a variable that is to be monitored for threshold crossing, and
generates a self event with the specified flag value when the threshold is crossed.
You will find a bit of discussion about it here
http://www.neuron.yale.edu/neuron/stati ... etcon.html