Justin N. Craig and Dr. Robert E. Seegmiller, Zoology

One of the most complicated and difficult to comprehend organ systems in embryological development is the nervous system. In the study of embryology, one realizes that the understanding of human origin exists and must be studied not only in three dimensions, but also the fourth, i.e. time. The complex folding and sealing of the neural tube, the arching through space and enlargement to form hollow areas for the developing portions of the brain, spinal cord, and neurons, can best be comprehended in a four dimensional manner. One of the greatest mysteries of the human body is still the brain, and if we can understand its development from the beginning, then as Aristotle once said, we can then “have the finest view of it.” Understanding normal development is the first step, a launching pad from which our analysis will aid in the research of abnormal development. Deformities are prevalent in the nervous system development partly because of its large critical period, or time frame during which teratogens are hazardous to it. Sufficient folic acid is needed as early as the day of conception to prevent neural tube defects such as spina bifida, and alcohol must be avoided throughout pregnancy to prevent Fetal Alcohol Syndrome. It is upon this system of embryological development- the nervous system- that I proposed to illustrate in four dimensions.

My purpose and plan was to create an animated 3-dimensional video, and accompany it with still models, of the developing human nervous system. These images I would then have incorporated into a multi-media teaching tool allowing for study and exploration of the embryonic nervous system. Arrangements were made for programming experts at the Center for Instructional Design (CID) to collaborate on the programming and application of this teaching tool.

In collaboration with Robert E. Seegmiller, a professor of embryology at BYU, I began my first step in creating such an animated 3-D model, the study and conceptual analysis stage. I outlined in chart form, a step-by-step development of the nervous system, written and then sketched, with all the significant anatomical features and their dates of development included. The difficulty in creating such an all-inclusive timeline lied in the variety of sources I relied upon. Much of embryological research is and has been carried out through the comparative study of rat embryos. With a lack of human embryos for dissection, and with good reason, some researchers differ to as much as a day or two on their estimation of the occurrence of certain key phases in human development. The developing embryo is also difficult to see in an unadulterated state, as it must be removed from the womb and the have its amniotic sac cut away before it can be studied and photographed. For a period of time the nervous system is confided to a developing space, with no form to it but the single cell layer surrounding the space. This stage can only be visualized with the use of numerous cross-sectional slides. I had to have an in depth understanding of the entire form, step by step through time, if I were to recreate that form in a 3- dimensional program. The research and understanding required caused this step of the plan to last a bit longer than expected.

Once this timeline was complete, I proceeded to create key-frames, important stages of development, out of clay so that I might have 3-dimensional models from which to conceptualize the computer simulated embryo. At the same time, I continued to compose a narration that would accompany the animation, describing the events, anatomical features, and the dates as they transpired. Again I ran into another two delays. My animation was of the nervous system, yet to show the folding of the neural tube the entire embryo must be animated. Unless I were to ignore accuracy entirely, I needed to study the development of the endocardial bulge (developing heart), somites, and pharyngeal branches if they were to appear correctly in the first portion of the video.

Though the nervous system develops throughout the nine month gestational period, many of the key events occur in the first few weeks. These events overlap each other repeatedly. This makes the teaching of neurulation, cytodifferentiation, and the flexing of the spinal tube difficult to explain separately as they occur simultaneously to the viewer’s eyes. Gradually I developed a system by which the first event to begin could be described in its entirety before backing up and explaining the next event, occasionally from a different perspective. At the conclusion I showed the entire process occurring so that all actions transpiring simultaneously could be compared as well.

Once I began working on the computer there were the usual delays of network malfunctions and my own difficulties with the program. As I worked I discovered better ways to accomplish the transitions I desired, and felt the need to return to previous portions of the animation and design them again using the new and improved method. After the first minute or two of the animation were ready, I included Professor Seegmiller and a CID representative for their input and appraisal of the animation. From this meeting I came away with two realizations, the first of which was that my research had placed me in a position to truly evaluate some portions of embryological development on a professional level. I also saw the results of my efforts when the CID representative was able to learn in a matter of minutes that which takes students of embryology a lecture or two, with chapter reading in between, to comprehend.

Currently the CID is awaiting my finished animation and models as I conclude my project utilizing the 3-dimensional programs at my graduate school. By the end of this fall semester Professor Seegmiller may be showing this interactive CD to his embryology, anatomy, or premed students.