Garth Thompson - Advisor, Shella Keilholz, PhD

"Anti-correlated Relationship between Networks in the Human Brain Predicts Vigilance on Time Scales from Seconds to Minutes"

The ability to steadily pay attention is an important skill which can be measured with the psychomotor vigilance task (PVT). Slow performance on the PVT has been related to activation of a group of brain regions with a coordinated low-frequency signal known as the default mode network. The default mode network’s signal tends to be anti-correlated with another network known as the task positive network. Greater anti-correlation has been related to less variable performance on a different task, but thus far has only been calculated on time scales of entire functional magnetic resonance imaging (fMRI) scans, six to twelve minutes long. Recent evidence will be presented that suggests that this anti-correlation, as measured by fMRI, is related to fast performance on the PVT not only for entire scans (as seen previously) but also for short (12.3s) windows and the simple difference in signal between the two networks. This relationship was also demonstrated using intra-individual analysis 4s to 8s prior to task performance. Neither the default mode network nor task positive network’s signal alone was predictive of behavior by itself, suggesting that anti-correlation itself is a biomarker of behavior and not merely a pre-processing artifact. The short time scale and intra-individual results suggest that anti-correlation between functional brain networks can potentially be used as a real-time biomarker of human vigilance.

Ian Campbell - Advisor, Bob Taylor, PhD and John Oshinski, PhD

"Biomechanical Lesion-Specific Modeling of Differences Between Plaque Rupture and Plaque Erosion"

Plaque erosion is a recently-described cause of sudden death where a thrombus forms over an atherosclerotic plaque without any rupture of the fibrous cap. Victims of plaque erosion are typically women and younger men, demographics not generally regarded as having high risk for sudden coronary death. Despite identification, the cause of plaque erosion remains unknown and has been virtually unstudied from a biomechanical perspective. In this study, we employ a unique lesion-specific, histology-based finite element model of solid wall stresses to investigate biomechanical differences between plaque rupture and plaque erosion.

The Graduate and Post-Doc (GaP) Seminar Series is a weekly event of research presentations by two graduate students or post-docs conducting bio-related research.  The series is organized and sponsored by the Parker H. Petit Institute for Bioengineering and Bioscience (IBB) with additional support from the Wallace H. Coulter Department of Biomedical Engineering. It is held every Wednesday at 12:00pm in IBB 1128 and refreshments are provided. If your research group or department would like to present at future seminars, please contact Manu Platt, PhD at manu.platt@bme.gatech.edu.