Figure 8: Impact of astrocytes, via EAAT2, on Hebbian plasticity.
From: Astrocytes gate Hebbian synaptic plasticity in the striatum
Schematic representation of the role of astrocytes, via EAAT2, on Hebbian plasticity in the striatum. (a) Transient EAAT2 blockade prevents the expression of STDP, instead favoring non-Hebbian plasticity (timing-independent LTP). This LTP is mediated by extrasynaptic NMDAR and LTD is dependent on the activation of striatal GABAergic microcircuits. In these conditions, unpaired activity is sufficient to induce LTP. (b) The physiological expression and activity of EAAT2 allows the emergence of Hebbian plasticity (bidirectional STDP). Depending on the order of pre- and postsynaptic activity, NMDAR-mediated t-LTP or endocannabinoid-mediated t-LTD is induced. (c) EAAT2 overexpression by limiting glutamate spillover prevents STDP expression. Thus, the efficiency of glutamate uptake, most through astrocytic EAAT2, gates the expression of Hebbian synaptic plasticity in the striatum.
