Two opposite voltage-dependent currents control the unusual early development pattern of embryonic Renshaw cell...

Area of Science:

• Neuroscience
• Developmental Biology
• Computational Biology

Background:

• Renshaw cells (V1^R) are crucial interneurons in spinal cord circuitry.
• They are known to be excitable and functionally heterogeneous.
• Their developmental trajectory and the mechanisms driving their heterogeneity are not fully understood.

Purpose of the Study:

• To investigate the electrophysiological properties and functional diversity of embryonic mouse Renshaw cells (V1^R).
• To elucidate the underlying mechanisms responsible for their functional heterogeneity during early spinal cord development.
• To analyze the developmental trajectory of V1^R from embryonic day 11.5 to 16.5.

Main Methods:

• Utilized a combination of experimental approaches.
• Employed biophysical modeling and dynamical systems theory.
• Analyzed electrophysiological properties of V1^R in developing mouse spinal cord.

Main Results:

• Identified functional clusters of V1^R as early as embryonic day 11.5.
• Observed a transitory involution process where V1^R lose their tonic firing ability.
• Demonstrated that the ratio of persistent sodium to delayed rectifier potassium conductance dictates V1^R discharge patterns.

Conclusions:

• Functional diversity in embryonic V1^R arises from a simple mechanism involving two ubiquitous voltage-dependent conductances.
• This mechanism controls the early developmental trajectory and functional specialization of V1^R.
• The interplay between persistent sodium and delayed rectifier potassium conductances is essential for V1^R functional heterogeneity.