LIF Neuron Network with STDP Plasticity (2D)

Drive

External current I_ext 1.05

Noise σ 0.35

Synaptic coupling g 1.00

STDP Plasticity

A+ (potentiation) 0.010

A− (depression) 0.012

Live Readout

Elapsed time

0.0 s

Pop. firing rate

0.0 Hz

Mean E→E weight

0.500

Active neurons

0 / 50

How it works

50 leaky integrate-and-fire (LIF) neurons — 40 excitatory, 10 inhibitory — are recurrently wired with ~12% connection probability. Each neuron's membrane voltage follows:

τ_m dV/dt = −(V − V_rest) + I_ext + σ·ξ(t)
spike when V ≥ V_th  →  V ← V_reset, refractory 2 ms
on spike, every outgoing synapse delivers ±w·g to its target

Excitatory synapses depolarize their targets, inhibitory ones hyperpolarize them. Only excitatory→excitatory synapses are plastic: spike-timing-dependent plasticity (STDP) tracks an exponentially decaying trace per neuron and, on every spike pair, potentiates a synapse when the presynaptic spike preceded the postsynaptic one (Δw = A₊·trace_pre) and depresses it when the order was reversed (Δw = −A₋·trace_post), clamped to [0, 1].

Raster — every dot is one spike; excitatory rows green, inhibitory rows blue.
Voltage trace — membrane potential of a sampled excitatory neuron, with its firing threshold marked.
Weight trace — the mean strength of all E→E synapses over time; watch it drift as STDP potentiates or depresses the recurrent excitatory loop under different drive.

Excitatory spike Inhibitory spike Mean E→E weight