Modulation of neuronal activity by astrocytes: studying interactions between potassium homeostasis, astrocyte-derived energy metabolites and cellular signaling.

The central position of astrocytes in the brain parenchyma allows them to play critical roles in the modulation of energy metabolism and regulation of extracellular ion and neurotransmitter composition. Neuronal activity leads to significant fluctuations in extracellular potassium that have a sizeable functional impact on neuronal signaling. Simultaneously, neurotransmitters, in particular glutamate, are released by neurons. Both glutamate and potassium need to be tightly regulated to ensure accurate synaptic transmission. Both are also signals for astrocytes to provide a metabolic response, characterized by enhanced lactate production. We investigate these spatiotemporal interactions in transgenic or virus-injected mice or in human brain tissue, mainly using one- and two-photon imaging, combined with electrophysiology.