Reset while keeping network connections - NEST Users

16 Apr 2020

Dear Nest community,

I have a network of LIF neurons ('iaf_cond_alpha') and I would like to
implement STDP synapses, rather than the

standard 'static_synapse'. I would like to be able to set a subset of
the network to STDP synapses (e.g. all excitatory ones)

and leave the rest static. This is how have implemented that currently
(see code). I am using a for loop because I want to

see how STDP changes the activity over time (over many iterations),
which leaves me with the following two questions:

*1. Is this a correct way to implement STDP in nest? *

*2. Is there a way to reset the network such that the connections are
not lost? *ResetNetwork() and ResetKernel() both seem to

destroy all the network connections. While I would like to keep them,
so that the network becomes less and less randomly

connected per simulation.

Thank you!

Best,

Daphne

*CODE*

        # define network connectivity
        conn_dict = {'rule': 'pairwise_bernoulli', 'p': 0.1}
        # define dicts for static synapses
        static_ex_params = {'model':'static_synapse','weight':
6.0,
'delay': 1.5}
        static_in_params = {'model':'static_synapse','weight':
-96.0,
'delay': 1.5}

        if self.STDP == 'ALL':
            # all synapses should be stdp ones, make connections
between the two populations:
            # from exc neurons to all neurons
            nest.Connect(neurons_all[:self.NE], neurons_all,
conn_dict, self.syn_params_ex)
            # from interneurons to all neurons
            nest.Connect(neurons_all[self.NE:], neurons_all,
conn_dict, self.syn_params_in)

        elif self.STDP == 'EXC':
            # keep the inhibitory synapses static
            # connections from exc neurons to all neurons
            nest.Connect(neurons_all[:self.NE], neurons_all,
conn_dict, self.syn_params_ex)
            # connections from interneurons to all neurons
            nest.Connect(neurons_all[self.NE:], neurons_all,
conn_dict, static_in_params)

where

   synapse_params_in = {
        'model':'stdp_synapse',
        'lambda': 0.01,
        'alpha': 1.0,
        'delay': 1.5,
        'weight':-95.0
    }