Application of Statistical Physics Methods to Quantify the Aging Process in the Brain

Speaker: Joao Ricardo Santos

When: September 9, 2013 (Mon), 02:30PM to 03:30PM (add to my calendar)
Location: PRB 365

This event is part of the Preliminary Oral Exam.

Examining Committee: H. E. Stanley, Rama Bansil, Tulika Bose, Shyamsunder Erramilli

Abstract:

It has been recently discovered that during the normal aging process, myelinated axons (or nerve fibers) in the fornix area of the rhesus monkey brain decrease in number with age, between 27% and 45%. However, this decrease in the number of myelinated axons is not accompanied with a reduction of the fornix volume. In fact, Peters et al. have recently shown, via light and electron microscopy, that there is no change of the cross–sectional area of the fornix area with age. Furthermore, the decrease of the myelinated axon density correlates with an increase of cognitive impairment of the rhesus monkeys studied.

In this work, we investigate whether, associated with a decrease in density of myelinated axons, there is a change in the spatial relationship (i.e. structure) between the myelinated axons in the fornix area that could provide insights in the aging process. The bundle of nerve fibers that collectively compose the fornix is crucial in normal cognitive functions, especially memory functions.

As such, we developed a recognition algorithm to help us identify myelinated axons in electron microscopy images of the fornix area of the rhesus monkey brain and, from that data, are able to apply statistical physics methods to determine what structural features are more affected by the aging process. These features are later calculated for random generated samples and compared to the original ones. Finally, we can model the aging process observed in myelinated axons in the fornix area, and better understand (and possibly delay) aging effects.