neuromodulated_stdp_synapse

neuromodulated_stdp - Synapse model for spike-timing dependent plasticity modulated by a neurotransmitter such as dopamine

Description

stdp_dopamine_synapse is a connection to create synapses with dopamine-modulated spike-timing dependent plasticity (used as a benchmark model in [1], based on [2]). The dopaminergic signal is a low-pass filtered version of the spike rate of a user-specific pool of neurons. The spikes emitted by the pool of dopamine neurons are delivered to the synapse via the assigned volume transmitter. The dopaminergic dynamics is calculated in the synapse itself.

References

[1]

Potjans W, Morrison A, Diesmann M (2010). Enabling functional neural circuit simulations with distributed computing of neuromodulated plasticity. Frontiers in Computational Neuroscience, 4:141. DOI: https://doi.org/10.3389/fncom.2010.00141

[2]

Izhikevich EM (2007). Solving the distal reward problem through linkage of STDP and dopamine signaling. Cerebral Cortex, 17(10):2443-2452. DOI: https://doi.org/10.1093/cercor/bhl152

Parameters

Name	Physical unit	Default value	Description
d	ms	1ms	Synaptic transmission delay
tau_tr_pre	ms	20ms	STDP time constant for weight changes caused by pre-before-post spike pairings.
tau_tr_post	ms	20ms	STDP time constant for weight changes caused by post-before-pre spike pairings.
tau_c	ms	1000ms	Time constant of eligibility trace
tau_n	ms	200ms	Time constant of dopaminergic trace
b	real	0.0	Dopaminergic baseline concentration
Wmax	real	200.0	Maximal synaptic weight
Wmin	real	0.0	Minimal synaptic weight
A_plus	real	1.0	Multiplier applied to weight changes caused by pre-before-post spike pairings. If b (dopamine baseline concentration) is zero, then A_plus is simply the multiplier for facilitation (as in the stdp_synapse model). If b is not zero, then A_plus will be the multiplier for facilitation only if n - b is positive, where n is the instantenous dopamine concentration in the volume transmitter. If n - b is negative, A_plus will be the multiplier for depression.
A_minus	real	1.5	Multiplier applied to weight changes caused by post-before-pre spike pairings. If b (dopamine baseline concentration) is zero, then A_minus is simply the multiplier for depression (as in the stdp_synapse model). If b is not zero, then A_minus will be the multiplier for depression only if n - b is positive, where n is the instantenous dopamine concentration in the volume transmitter. If n - b is negative, A_minus will be the multiplier for facilitation.

State variables

Name	Physical unit	Default value	Description
w	real	1.0
n	real	0.0	Neuromodulator concentration
c	real	0.0	Eligibility trace
pre_tr	real	0.0
post_tr	real	0.0

Source code

The model source code can be found in the NESTML models repository here: neuromodulated_stdp_synapse.