The Coordinating Role of the Actin Cytoskeleton in Short-Term Neural Network Plasticity Involving Excitatory and Inhibitory Synapses

The problem of frequency coding is closely related to studies of the mechanisms by which inhibitory interneurons are involved in neural network plasticity. This review outlines the basic principles of the integration of inhibitory interneurons into the formation of spatiotemporal patterns of neuronal activity during signal processing. Contemporary concepts of the dynamic nature of synaptic responses and their instability during ongoing activity are analyzed. The results discussed here indicate that short-term plasticity involves close interactions between excitatory and inhibitory synapses. The influence of inhibitory potentials on the activity of intracellular mediators influencing the dynamics of postsynaptic modifications of excitatory and inhibitory synapses is discussed. Much is currently known of the molecular mechanisms of these modifications, though no conceptual ideas have thus far been proposed regarding the key factors combining intracellular signaling reactions into a single system ensuring the balance and “adaptivity” of modifications of excitatory and inhibitory synapses. Arguments in favor of a coordinating role of the actin cytoskeleton are presented. It is suggested that the source of postsynaptic modifications of inhibitory synapses is the rapid adaptation of the actin cytoskeleton and associated proteins to any deviations from the optimal balance between excitation and inhibition.