Journal Article

Astrocytes close a motor circuit critical period

Freeman, Marc R., Doe, Chris Q., Perez-Catalan, Nelson A., Ackerman, Sarah D.

2021

Overview

Critical periods—brief intervals during which neural circuits can be modified by activity—are necessary for proper neural circuit assembly. Extended critical periods are associated with neurodevelopmental disorders; however, the mechanisms that ensure timely critical period closure remain poorly understood 1 , 2 . Here we define a critical period in a developing Drosophila motor circuit and identify astrocytes as essential for proper critical period termination. During the critical period, changes in activity regulate dendrite length, complexity and connectivity of motor neurons. Astrocytes invaded the neuropil just before critical period closure 3 , and astrocyte ablation prolonged the critical period. Finally, we used a genetic screen to identify astrocyte–motor neuron signalling pathways that close the critical period, including Neuroligin–Neurexin signalling. Reduced signalling destabilized dendritic microtubules, increased dendrite dynamicity and impaired locomotor behaviour, underscoring the importance of critical period closure. Previous work defined astroglia as regulators of plasticity at individual synapses 4 ; we show here that astrocytes also regulate motor circuit critical period closure to ensure proper locomotor behaviour. The duration of a critical period of plasticity in the developing Drosophila motor circuit, during which motor neurons display activity-dependent refinement of neurite structure and connectivity, is dependent on astrocyte to motor neuron Neuroligin–Neurexin signalling.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 14/19 / 38/1 / 38/35 / 38/39 / 42/35 / 42/89 / 631/136/368 / 631/378/2571 / 64/24 / Ablation / Analysis / Animals / Astrocytes / Astrocytes - physiology / Cell Adhesion Molecules, Neuronal - metabolism / Circuits / Closures / Control / Critical period / Critical Period, Psychological / Critical periods (Biology) / Dendrites / Dendrites - physiology / Dendritic structure / Drosophila / Drosophila melanogaster - cytology / Drosophila melanogaster - physiology / Efferent Pathways - physiology / Female / Genetic screening / Humanities and Social Sciences / Insects / Locomotion - physiology / Male / Microscopy / Microtubules / Microtubules - metabolism / Morphology / Motor cortex / Motor neurons / Motor Neurons - physiology / multidisciplinary / Neural networks / Neurodevelopmental disorders / Neuronal Plasticity - physiology / Neurons / Neuropil / Neuropil - physiology / Physiological aspects / Receptors, Cell Surface - metabolism / Regulators / Science / Science (multidisciplinary) / Signal Transduction / Signaling / Synapses - physiology / Time Factors