Editor’s Pick: New insights on compensatory synaptic mechanisms during development

Reviewing Editor Matthew Grubb, Ph.D. selected this paper and explains why he considers it noteworthy.

Neuronal circuits and their constituent cells use a wide range of "homeostatic" plastic processes to maintain particular functional attributes. These compensatory mechanisms can operate at the level of electrical excitability or synaptic connections, and can be vital for keeping network activity within defined operating limits. This is especially important during nervous system development, when continual maturational alterations mean that large changes in activity levels are a constant possibility. In this study, in which its reviewers described as "well-executed" and "exciting", an important new locus of synaptic compensatory plasticity is identified in the early developing chick autonomic nervous system.

Ratliff et al. studied sympathetic preganglionic neurons (SPNs), which send output from the central autonomic nervous system to their postsynaptic targets, the post-ganglionic neurons (PGNs) in the periphery. They chronically blocked GABAa-mediated transmission onto SPNs and found that these cells responded by increasing their intracellular chloride concentration. At a developmental stage where high internal chloride renders GABAa transmission depolarising, this plastic change would be predicted to compensate for decreased excitatory input by making excitatory GABAergic responses larger. Crucially, this response was cell-type-specific and was not seen at all in PGNs. By identifying synaptic scaling mechanisms that operate in central but not peripheral components of the early autonomic nervous system, this fascinating paper significantly expands our understanding of homeostatic plasticity in neuronal development.

Read the full article:

Plasticity in preganglionic and postganglionic neurons of the sympathetic nervous system during embryonic development
April Ratliff, Dobromila Pekala, and Peter Wenner