The role of astrocyte‐mediated plasticity in neural circuit development and function

Abstract

Neuronal networks are capable of undergoing rapid structural and functional changes called plasticity, which are essential for shaping circuit function during nervous system development. These changes range from short-term modifications on the order of milliseconds, to long-term rearrangement of neural architecture that could last for the lifetime of the organism. Neural plasticity is most prominent during development, yet also plays a critical role during memory formation, behavior, and disease. Therefore, it is essential to define and characterize the mechanisms underlying the onset, duration, and form of plasticity. Astrocytes, the most numerous glial cell type in the human nervous system, are integral elements of synapses and are components of a glial network that can coordinate neural activity at a circuit-wide level. Moreover, their arrival to the CNS during late embryogenesis correlates to the onset of sensory-evoked activity, making them an interesting target for circuit plasticity studies. Technological advancements in the last decade have uncovered astrocytes as prominent regulators of circuit assembly and function. Here, we provide a brief historical perspective on our understanding of astrocytes in the nervous system, and review the latest advances on the role of astroglia in regulating circuit plasticity and function during nervous system development and homeostasis.

Unraveling Axon Guidance during Axotomy and Regeneration

“…Nestin binds DCX and the cdk5 kinase activator p53, facilitating DCX phosphorylation by cdk5, a kinase that acts downstream of Sema3A [ 68 ]. Interestingly, studies in Xenopus laevis , comparing the transcriptomic response after spinal cord injury (SCI) in R versus NR stages, showed a differential increase in nestin transcripts in NR-stages, while no changes in R-stages, at 6 days post-injury (dpi) [ 69 , 70 ]. The timing of this response coincides with axon bundles crossing the injury gap in R-stages, and the lack of them, but the formation of a glial scar in NR-stages [ 70 , 71 ].…”

Training the Conductor of the Brainwave Symphony: In Search of a Common Mechanism of Action for All Methods of Neurofeedback

“…Nearly all of our synaptic connections are weakly formed in the first two years of life [17]. After this period of neurogenesis and synaptogenesis, our brains go through nearly two decades of experience-dependent synaptic strengthening and both experience-and neglect-dependent synaptic pruning [17,18].…”

“…In recent years, however, scientists have discovered that these cells provide substantially more functions than just structural integrity of the brain. For instance, astrocytes or astroglia, which are named for their star shape, help create and maintain the blood brain barrier, regulate the formation, maturation, maintenance, and stability of synapses, and regulate specific neuronal network activities through the inhibition of local, nonspecific activities [18,52,53].…”

“…Recent studies on astrocytes have revealed their heterogeneity in the human brain, which may be as diverse as all of the different neural circuits and networks [55,56]. In fact, astrocytes are implicated in the development, plasticity, and function of neural circuits [18]. Furthermore, astrocytes have bioelectrical properties that are created by calcium fluctuations across its membrane, which couple with neuronal firing and are likely the source of LFPs, which create the brainwaves that can be detected by EEG [57,58].…”

Rol de la Neuroglia en el Trastorno del Espectro Autista

“…También se sabe que los astrocitos liberan moléculas importantes, como el glutamato y la glutamina precursora de GABA, además de secretar captadores de especies reactivas de oxígeno (ROS) para la supervivencia neuronal. Por otra parte, los astrocitos que expresan la proteína ácida fibrilar glial (GFAP) actúan como células madres neuronales en las zonas neurogénicas adultas de la zona subventricular y subgranular del giro dentado del hipocampo (para una descripción completa de las funciones de los astrocitos ver también Wang & Bordey, 2008;Parpura & Verkhratsky, 2012;Haydon & Nedergaard, 2014;Perez-Catalan et al, 2021).…”