GABAergic-astrocyte signaling: A refinement of inhibitory brain networks

Abstract

Interneurons play a critical role in precise control of network operation. Indeed, higher brain capabilities such as working memory, cognitive flexibility, attention, or social interaction rely on the action of GABAergic interneurons. Evidence from excitatory neurons and synapses has revealed astrocytes as integral elements of synaptic transmission. However, GABAergic interneurons can also engage astrocyte signaling; therefore, it is tempting to speculate about different scenarios where, based on particular interneuron cell type, GABAergic-astrocyte interplay would be involved in diverse outcomes of brain function. In this review, we will highlight current data supporting the existence of dynamic GABAergic-astrocyte communication and its impact on the inhibitory-regulated brain responses, bringing new perspectives on the ways astrocytes might contribute to efficient neuronal coding.

Keywords: GABAergic interneurons; astrocyte; excitation/inhibition balance; gliotransmission; synaptic plasticity.

Figure 1

Schematic cortical circuit showing different neuron types interaction and their functional outputs. (a) Neuronal circuits based on interneuron‐principal cell connectivity. Yellow dots represent GABAergic point‐to‐point signaling. (b) GABAergic modulation of network activity responses driven by excitatory (top) and inhibitory inputs (bottom) in canonical neuronal circuits

Figure 2

Schematic cortical circuit including astrocytes. (a) Astrocytes superimpose an additional layer of signaling to GABAergic synapses, which involves distant synapses and different time scales. (b) Astrocytes modulate both the excitatory (top) and inhibitory (bottom) drive onto principal cells and interneurons (red dots), enhancing or reducing synaptic activity and final network. Note that astrocyte impact on particular excitatory and inhibitory synapses contributes to increase the computation capabilities of cortical networks