Example: CUBA (synapses)ΒΆ

CUBA example with delays.

Connection (no delay): 3.5 s DelayConnection: 5.7 s Synapses (with precomputed offsets): 6.6 s # 6.9 s Synapses with weave: 6.4 s Synapses with zero delays: 5.2 s

from brian import *
import time

start_time = time.time()
taum = 20 * ms
taue = 5 * ms
taui = 10 * ms
Vt = -50 * mV
Vr = -60 * mV
El = -49 * mV

eqs = Equations('''
dv/dt  = (ge+gi-(v-El))/taum : volt
dge/dt = -ge/taue : volt
dgi/dt = -gi/taui : volt
''')

P = NeuronGroup(4000, model=eqs, threshold=Vt, reset=Vr, refractory=5 * ms)
P.v = Vr
P.ge = 0 * mV
P.gi = 0 * mV

Pe = P.subgroup(3200)
Pi = P.subgroup(800)
we = (60 * 0.27 / 10) * mV # excitatory synaptic weight (voltage)
wi = (-20 * 4.5 / 10) * mV # inhibitory synaptic weight

Se = Synapses(Pe, P, model = 'w : 1', pre = 'ge += we')
Si = Synapses(Pi, P, model = 'w : 1', pre = 'gi += wi')
Se[:,:]=0.02
Si[:,:]=0.02
Se.delay='rand()*ms'
Si.delay='rand()*ms'

P.v = Vr + rand(len(P)) * (Vt - Vr)

# Record the number of spikes
Me = PopulationSpikeCounter(Pe)
Mi = PopulationSpikeCounter(Pi)
# A population rate monitor
M = PopulationRateMonitor(P)

print "Network construction time:", time.time() - start_time, "seconds"
print len(P), "neurons in the network"
print "Simulation running..."
run(1 * msecond)
start_time = time.time()

run(1 * second)

duration = time.time() - start_time
print "Simulation time:", duration, "seconds"
print Me.nspikes, "excitatory spikes"
print Mi.nspikes, "inhibitory spikes"
plot(M.times / ms, M.smooth_rate(2 * ms, 'gaussian'))
show()

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