The Journal of Neuroscience cover for the August 14 issue continues with part two of a three-part video that illustrates a study of a developing mouse auditory brainstem, set to an original score by musician Bill Mallers. The study 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. Click on the second image at right to view the full video.
Spirou, Director of the Center for Neuroscience and Professor of Otolaryngology, Physiology and Pharmacology at West Virginia University School of Medicine, says the second video tells the story of auditory cell development. It shows the developmental formation of calyx of Held nerve terminals and their postsynaptic targets in a mouse auditory brainstem, imaged with serial block-face scanning electron microscopy. At postnatal day two (P2), a single cell is shown, contacted by multiple small nerve terminals. Only one day later (P3), a cell is shown with three large competing inputs (colored blue, green, and yellow in order of decreasing size) contacting the cell body. The third cell is from a P4 mouse and illustrates further growth of nerve terminals and contact of the cell body by two large inputs, colored blue and green. The final cell is from P6, and is dominated by a single large input enveloping the postsynaptic cell body. The P6 cell is depicted on the cover image.
“We’re showing that suddenly, at P3, several inputs begin to grow and compete,” Spirou said. “Within just a few days a single input ‘wins’ and 1:1 innervation is established. This rapid time course is among the fastest across neural systems in mammals and makes the calyx system as a good model for development. Keep in mind that at day 6, the ear canals have not yet opened, so this occurs in advance of hearing airborne sound. We are interested in what drives these events with such a sharp onset and what mediates the competition.”
Spirou said that his team, spearheaded by graduate student and lead author Paul Holcomb, along with postdoctoral fellow Brian Hoffpauir, made the videos using two computer programs. They led the segmentation team of nearly 30 people in tracing the borders of objects in the EM image stack, using IMOD software, developed at University of Colorado at Boulder. IMOD is an open-source, cross-platform suite of modeling, display, and image processing programs used for 3D reconstruction and modeling of microscopy images with a special emphasis on electron microscopy data. The animations were created using Maxon Cinema 4D Studio software.
John Maunsell, editor-in-chief of The Journal, said that cover videos will be accepted for publication consideration going forward. The images can be viewed online along with the PDF versions of the articles, and by scanning the QR code in the print version with a mobile device.
The third video of “Synaptic Inputs Compete During Rapid Formation of the Calyx of Held: a New Model System for Neural Development” will be posted on SfN.org and on The Journal of Neuroscience on August 21.
Read about the first video in the series that relates to the “Synaptic Inputs Compete During Rapid Formation of the Calyx of Held: a New Model System for Neural Development” study.