A variety of competitive properties arising from STDP incorporating metaplastic regulation

Abstract

Spike-timing-dependent plasticity (STDP) induces competition among inputs, which is required for the construction of functional neuronal circuits, while maintaining the basic features of Hebbian plasticity. Here, we theoretically examine the competitive function of STDP incorporating a metaplastic activity-dependent feedback (ADFB) mechanism, wherein higher postsynaptic activity suppresses LTP, in cases where a neuron receives two groups of correlated inputs. We demonstrate that there are four distinct types of competitive properties depending on the relative input frequency between the different groups and the correlation time among the inputs within the same group. (1) Competition with a bi-stable synaptic weight distribution (for identical frequencies and brief correlation). (2) No competition (for identical frequencies and prolonged correlation). (3) Competition preferring strong input activity (for different frequencies and brief correlation).(4) Competition preferring weak input activity (for different frequencies and prolonged correlation). This may suggest that ADFB regulation can modulate the Hebbian competition properties associated with STDP to increase its ability to reflect input firing properties.