PubMed 26269551
Referenced in: none
Automatically associated channels: Slo1
Title: Potassium currents dynamically set the recruitment and firing properties of F-type motoneurons in neonatal mice.
Authors: Félix Leroy, Boris Lamotte d'Incamps, Daniel Zytnicki
Journal, date & volume: J. Neurophysiol., 2015 Sep , 114, 1963-73
PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/26269551
Abstract
In neonatal mice, fast- and slow-type motoneurons display different patterns of discharge. In response to a long liminal current pulse, the discharge is delayed up to several seconds in fast-type motoneurons and their firing frequency accelerates. In contrast, slow-type motoneurons discharge immediately, and their firing frequency decreases at the beginning of the pulse. Here, we identify the ionic currents that underlie the delayed firing of fast-type motoneurons. We find that the firing delay is caused by a combination of an A-like potassium current that transiently suppresses firing on a short time scale and a slowly-inactivating potassium current that inhibits the discharge over a much longer time scale. We then show how these intrinsic currents dynamically shape the discharge threshold and the frequency-input function of fast-type motoneurons. These currents contribute to the orderly recruitment of motoneurons in neonates and might play a role in the postnatal maturation of motor units.