Modeling Hypoglossal Motoneurons in the Developing Rat

Publication date: Available online 26 July 2018Source: Respiratory Physiology & NeurobiologyAuthor(s): Paul Allen Williams, Clarissa Dalton, Christopher G. WilsonAbstractWe hypothesize that developmental changes in motoneuron volume or surface area in the hypoglossal motor nucleus (XII) can alter the biophysical properties that contribute to motor output. We used the Golgi-Cox technique to stain developing hypoglossal motoneurons (XII MNs) at three postnatal ages (P3, 10, & 17). We removed Sprague-Dawley rat pup brains, processed, sectioned, stained, imaged, and performed 3D reconstructions to quantify the morphometrics of XII MNs. We then used the simulation environment, NEURON, to model the biophysical properties from digitally reconstructed neurons and compared our results to previously published experiments. The total volume of neurons increased from 4,766 μ m3 for P3 to 16,904 μ m3 for P17 while the total surface area increased from 4,258 μ m2 to 13,510 μ m2 respectively. The P3 simulations required a 10-fold reduction in the hyperpolarization-activated current and doubling of the membrane capacitance to match experimental results. XII MN morphology showed a direct relationship with passive electrophysiological properties and recapitulates the changes seen experimentally.
Source: Respiratory Physiology and Neurobiology - Category: Respiratory Medicine Source Type: research