Astrocytes in memory formation and maintenance

Abstract

Learning and memory are fundamental but highly complex functions of the brain. They rely on multiple mechanisms including the processing of sensory information, memory formation, maintenance of short- and long-term memory, memory retrieval and memory extinction. Recent experiments provide strong evidence that, besides neurons, astrocytes crucially contribute to these higher brain functions. However, the complex interplay of astrocytes and neurons in local neuron–glia assemblies is far from being understood. Although important basic cellular principles that govern and link neuronal and astrocytic cellular functions have been established, additional mechanisms clearly continue to emerge. In this short essay, we first review current technologies allowing the experimenter to explore the role of astrocytes in behaving animals, with focus on spatial memory. We then discuss astrocytic signaling mechanisms and their role in learning and memory. We also reveal gaps in our knowledge that currently prevent a comprehensive understanding of how astrocytes contribute to acquisition, storage and retrieval of memory by modulating neuronal signaling in local circuits.

Perturbation of 3D nuclear architecture, epigenomic aging and dysregulation, and cannabinoid synaptopathy reconfigures conceptualization of cannabinoid pathophysiology: part 2—Metabolome, immunome, synaptome

“…It should also be underscored that CB1Rs have been identified on astrocytes. This becomes important when it is understood that astrocytes are now known to play an integral and active part in neurotransmission and form, together with endothelial cells, the “quadripartite synapse” ( 47 , 48 ).…”

“…Astrocytes are bound together via gap junctions and signal to each other by calcium waves. These waves have been shown to be critical in the formation of various kinds of memory including short-term, long-term, working, spatial, and aversive memories ( 47 , 48 ).…”

“…The role of lactate has metamorphosed from being conceptually considered as a metabolic waste product, to an energy substrate, to an important metabolic signal ( 47 ). Astrocytes provide lactate to neurons via an astrocyte-to-neuron lactate shuttle in order to supplement their very high needs for energy, especially during active firing states ( 47 ).…”

Modulation of Pyruvate Export and Extracellular Pyruvate Concentration in Primary Astrocyte Cultures

“…Astrocytes play an important role in brain energy metabolism [ 1 – 4 ], but have also crucial functions in brain development [ 5 ], (ion) homeostasis [ 6 – 9 ], the regulation and modulation of neuronal signals [ 10 , 11 ], memory formation [ 12 ] and the protection against toxins and oxidative stress [ 13 – 15 ]. Although astrocytes are considered as a rather glycolytic cell type [ 16 ], also the oxidative metabolism plays an important role for astrocytic energy regeneration [ 17 – 19 ].…”

β-lapachone-mediated WST1 Reduction as Indicator for the Cytosolic Redox Metabolism of Cultured Primary Astrocytes

“…In brain, astrocytes have a strategically important location between capillaries and other parenchymal cells, thereby regulating the exchange of substances between blood and brain [ 8 ]. In addition, astrocytes have a plethora of important functions in brain metabolism, in the defence against oxidative stress and toxins, in the homeostasis of the extracellular environment and they contribute also to the development and maintenance of cognitive functions [ 9 – 13 ].…”