Synapses

Stochastic-computing synapses implement weighted connections between neurons using bitstream multiplication (AND gates).

Class	Learning	Use case
BitstreamSynapse	None (static weight)	Inference, fixed networks
StochasticSTDPSynapse	Hebbian STDP	Unsupervised learning
RewardModulatedSTDPSynapse	Three-factor R-STDP	Reinforcement learning
BitstreamDotProduct	None	Multi-input weighted sum
TripletSTDP	Pfister-Gerstner 2006	Rate-dependent cortical plasticity
BCMSynapse	Sliding threshold	Metaplasticity, selectivity
ClopathSTDP	Voltage-based	Unifies rate + timing plasticity
TripartiteSynapse	Astrocyte-modulated	Neuron-glia-synapse coupling
GapJunction	Electrical coupling	Interneuron synchrony

Static Synapse

::: sc_neurocore.synapses.sc_synapse.BitstreamSynapse

STDP Synapse

::: sc_neurocore.synapses.stochastic_stdp.StochasticSTDPSynapse

Reward-Modulated STDP

::: sc_neurocore.synapses.r_stdp.RewardModulatedSTDPSynapse

Dot Product

::: sc_neurocore.synapses.dot_product.BitstreamDotProduct

Triplet STDP (Pfister-Gerstner 2006)

::: sc_neurocore.synapses.triplet_stdp.TripletSTDP

BCM Metaplasticity (Bienenstock-Cooper-Munro 1982)

::: sc_neurocore.synapses.bcm.BCMSynapse

Voltage-Based STDP (Clopath et al. 2010)

ClopathSTDP implements the two voltage-gated pathways from Clopath et al.:

• LTD is applied on presynaptic spikes when the slow postsynaptic voltage trace is above theta_minus.
• LTP is applied when the current postsynaptic voltage is above theta_plus and the fast postsynaptic voltage trace is above theta_minus.

This makes the public contract trace-dependent rather than spike-pair only: regression tests should preserve both the LTD path under moderate depolarisation and the LTP path under strong depolarisation.

::: sc_neurocore.synapses.clopath_stdp.ClopathSTDP

Tripartite Synapse (Astrocyte Coupling)

TripartiteSynapse couples presynaptic activity to an internal astrocyte model before applying the effective synaptic weight:

• presynaptic spikes accumulate a glutamate signal that drives astrocyte IP3 production;
• astrocyte calcium above ca_threshold facilitates the synaptic weight through the configured facilitation gain;
• calcium below threshold relaxes the weight back toward base_weight through depression_rate;
• w_min and w_max bound the effective weight in both regimes.

The public contract is therefore stateful across synapse and astrocyte state. Tests should preserve IP3 accumulation from sustained presynaptic activity, calcium-gated facilitation, baseline recovery, and bounded effective weights.

::: sc_neurocore.synapses.tripartite.TripartiteSynapse

Gap Junction (Electrical Synapse)

::: sc_neurocore.synapses.gap_junction.GapJunction