The role of correlated inhibitory cell firing

Maturation of γ-aminobutyric acid (GABA) function within the visual cortex is known to be involved in ocular dominance (OD) plasticity. However, only the circuits mediated by specific GABA_A receptors can induce OD plasticity, implying a role of local GABA functions in this process. Here, we simulated the dynamics of synaptic population by spike-timing-dependent plasticity (STDP) to study the effects of local inhibitory functions on plasticity. Various forms of inhibitory pathways, such as horizontal, backward, and independent inhibition, were examined. We specifically investigated the activity-dependent competition between groups of inputs, which is required for the induction of experience-dependent plasticity. We show that the temporal correlation between excitatory and inhibitory inputs produced by horizontal inhibition facilitates competition. Conversely, the correlation between inhibitory inputs and postsynaptic activity through feedback inhibition suppresses competition. Our results may suggest that the distinct local GABA circuits can differently regulate the occurrence and level of visual plasticity by controlling the synaptic competition.