.. currentmodule:: brian

.. index::
   pair: example usage; NeuronGroup
   pair: example usage; run
   pair: example usage; Synapses
   pair: example usage; raster_plot
   pair: example usage; PulsePacket
   pair: example usage; SpikeMonitor

.. _example-synapses_Diesmann_et_al_1999:

Example: Diesmann_et_al_1999 (synapses)
=======================================

Synfire chains
--------------
M. Diesmann et al. (1999). Stable propagation of synchronous spiking in cortical
neural networks. Nature 402, 529-533.

::

    from brian import *
    
    # Neuron model parameters
    Vr = -70 * mV
    Vt = -55 * mV
    taum = 10 * ms
    taupsp = 0.325 * ms
    weight = 4.86 * mV
    # Neuron model
    eqs = '''
    dV/dt=(-(V-Vr)+x)*(1./taum) : volt
    dx/dt=(-x+y)*(1./taupsp) : volt
    dy/dt=-y*(1./taupsp)+25.27*mV/ms+\
        (39.24*mV/ms**0.5)*xi : volt
    '''
    # Neuron groups
    P = NeuronGroup(N=1000, model=eqs,
        threshold=Vt, reset=Vr, refractory=1 * ms)
    Pinput = PulsePacket(t=50 * ms, n=85, sigma=1 * ms)
    # The network structure
    Pgp = [ P.subgroup(100) for i in range(10)]
    C = Synapses(P, P, model='w:volt', pre='y+=w')
    for i in range(9):
        C[Pgp[i], Pgp[i + 1]]=True
        C.w[Pgp[i], Pgp[i + 1]]=weight
    Cinput = Synapses(Pinput, Pgp[0], model='w:volt', pre='y+=w')
    Cinput[:,:]=True
    Cinput.w[:,:]=weight
    # Record the spikes
    Mgp = [SpikeMonitor(p) for p in Pgp]
    Minput = SpikeMonitor(Pinput)
    monitors = [Minput] + Mgp
    # Setup the network, and run it
    P.V = Vr + rand(len(P)) * (Vt - Vr)
    run(100 * ms)
    # Plot result
    raster_plot(showgrouplines=True, *monitors)
    show()