Design and Implementation of BCM Rule Based on Spike-Timing Dependent Plasticity

TL;DR

This paper investigates whether BCM learning can emerge from STDP rules by implementing two VLSI circuits for pair-based and triplet-based STDP and analyzing their behavior under Poissonian spike train stimulation.

Contribution

The study demonstrates that both pair-based and triplet-based STDP VLSI circuits can produce BCM-like threshold behavior, showing BCM as an emergent property of STDP.

Findings

Triplet-based STDP circuit exhibits BCM-like threshold behavior.

Pair-based STDP circuit also generates BCM-like behavior.

Simulation conducted using 0.35 um CMOS in HSpice.

Abstract

The Bienenstock-Cooper-Munro (BCM) and Spike Timing-Dependent Plasticity (STDP) rules are two experimentally verified form of synaptic plasticity where the alteration of synaptic weight depends upon the rate and the timing of pre- and post-synaptic firing of action potentials, respectively. Previous studies have reported that under specific conditions, i.e. when a random train of Poissonian distributed spikes are used as inputs, and weight changes occur according to STDP, it has been shown that the BCM rule is an emergent property. Here, the applied STDP rule can be either classical pair-based STDP rule, or the more powerful triplet-based STDP rule. In this paper, we demonstrate the use of two distinct VLSI circuit implementations of STDP to examine whether BCM learning is an emergent property of STDP. These circuits are stimulated with random Poissonian spike trains. The first circuit implements the classical pair-based STDP, while the second circuit realizes a previously described triplet-based STDP rule. These two circuits are simulated using 0.35 um CMOS standard model in HSpice simulator. Simulation results demonstrate that the proposed triplet-based STDP circuit significantly produces the threshold-based behaviour of the BCM. Also, the results testify to similar behaviour for the VLSI circuit for pair-based STDP in generating the BCM.