May 13, 2016

Colloquium Speaker: K. T. Ramesh

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 and founding Director of the Hopkins Extreme Materials Institute (HEMI) in 2012.

Colloquium Topic: Keeping Your Head in the Game: The Dynamics of Traumatic Brain Injury

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 (the Hopkins Head) that integrates information on the events that cause TBI with high-fidelity models of the anatomy and physiology of the living human brain. The model incorporates structural information obtained using MRI and DTI, and is validated against dynamic 3D live human brain data. Using event reconstruction approaches coupled with multiscale mechanics analyses, we demonstrate that such mild traumatic brain injury (diffuse axonal injury) may be dominated by rotational modes. The model is informed by cellular and subcellular experiments in situ on single axons, which will be discussed if time allows.

Our approach provides guidance on the likely domains of injury, the likely cognitive deficits, and perhaps even potential approaches to treatment, and we discuss some of the associated challenges.