Seminars

Abstract. The human brain is an extraordinary organ that is arguably the most important part of the body. It is also a complex soft structure that is subjected to dynamic loading throughout a human lifetime. This lecture describes how this structure is protected, and examines the conditions under which the protection fails, leading to traumatic brain injury (TBI). Our particular interest is in injuries arising within sports. We present here a computational approach that integrates information on the events that cause TBI with high-fidelity models of the anatomy and physiology of the living human brain to study the onset and specific forms of traumatic brain injury. Our approach (viewed as an "upstream" approach by the clinical community) provides guidance on the likely domains of injury, the likely cognitive deficits, and on the potential approaches to treatment. The model captures the essential features of diffuse axonal injury, which is characterized by damage to neural axons, using an axonal strain injury criterion. The model is informed by cellular and subcellular experiments in situ on single axons, and incorporates structural information obtained using MRI and DTI. Using event reconstruction approaches coupled with multiscale mechanics analyses, we demonstrate that such mild traumatic brain injury may be dominated by rotational modes. Our results may be used to develop protocols for reducing concussions in sports, to design protective helmets in sports and other applications, to develop protective restraints in automobiles, and to develop a better understanding of the mechanisms that lead to TBI.

Bio. K.T. Ramesh is the Alonzo G. Decker Jr. Professor of Science & Engineering at Johns Hopkins University. His research interests are in the physics of dynamic failure, impact biomechanics, and planetary scale impact problems. Prof. Ramesh received his doctorate from Brown University in 1987. After a short stint as a postdoctoral fellow at the University of California, San Diego, he joined the Department of Mechanical Engineering at Johns Hopkins in 1988, becoming Department Chair from 1999-2002, Director of the Center for Advanced Metallic and Ceramic Systems in 2001 and founding Director of the Hopkins Extreme Materials Institute in 2012.