The August 21 cover of The Journal of Neuroscience concluded a three-part series of video covers. It was the first of what The Journal editors hope will be many intriguing cover art images taken from videos. These videos illustrate a study on a developing mouse auditory brainstem, set to an original score by musician Bill Mallers. Click on the third image at the right to view the full video.
“Synaptic Inputs Compete During Rapid Formation of the Calyx of Held: a New Model System for Neural Development” was undertaken by a team from West Virginia University and the University of California, San Diego: Paul S. Holcomb, Brian K. Hoffpauir, Mitchell C. Hoyson, Dakota R. Jackson, Thomas J. Deerinck, Glen S. Marrs, Marlin Dehoff, Jonathan Wu, Mark H. Ellisman, and George A. Spirou.
Spirou, Director of the Center for Neuroscience and Professor of Otolaryngology, Physiology and Pharmacology at West Virginia University School of Medicine, says that video three explores the nature of competition between these developing nerve terminals.It shows reconstructions of two competing inputs (blue and green) onto a single cell in a mouse medial nucleus of the trapezoid body at postnatal day three, derived from sections imaged with serial block-face scanning electron microscopy.
As the movie progresses, the inputs are removed to reveal the apposed surface area between the two nerve terminals and postsynaptic cell membrane (also shown in blue and green). Rotation of the cell reveals that these two apposed regions do not overlap. In the cover image, competing inputs are made translucent so that the apposed surface areas (purple and yellow) can be viewed through the nerve terminal membranes.
“The key observation is that the competing inputs are on opposite sides of the cell and they don’t physically interact. This tells us that the competition is more like a 100-meter dash. It’s not as if the two inputs are directly interfering with each other, but both are trying to establish 1:1 innervation of the cell,” Spirou said. “In other neural systems, there is competition for the same postsynaptic territory, so this tells us that some of the rules for innervation are different from those systems. The target neuron may remove resources from the ‘losing’ input or indicate to local glia which input to remove.”
Spirou says that collaboration, not competition, is at the heart of this project. His team collaborated with the team led by Mark H. Ellisman at the National Center for Microscopy and Imaging Research (NCMIR), University of California, San Diego (UCSD).
“We brought the biological questions about calyx development — and Mark and his group at NCMIR, including Tom Deerinck, have the imaging tools. They also bring valuable expertise in tissue chemistry applied to biological systems so we can collect appropriate data to address our scientific questions. They are constantly developing methods to stain and label the tissue and improving hardware design to optimize the imaging. This study wouldn’t have been completed without both of our groups working together. This, to me, is the kind of meaningful collaboration that drives science in this age of rapidly advancing technology.”
Read about the first and second videos in the series that relate to the “Synaptic Inputs Compete During Rapid Formation of the Calyx of Held: a New Model System for Neural Development” study.