Fiber Tractography

Project Description

High Angular Resolution Diffusion Imaging (HARDI)
Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique in which the variations in the random motions, or diffusion, of water in neural tissues allows one to infer the structural and functional characteristics of the local tissue environment.  Our goal is to develop highly sensitive DTI data acquisition and analysis methods to quantitate white matter changes due to substance abuse in adolescents, from which to non-invasively derive quantitative measures of structural variations associated with abuse and their relationship to cognitive impairment, in order to assess the effects of this disorder and to guide in the diagnosis and treatment of its sufferers.

Disease Models
We are interested in examining the impact of substances on the developing brain, specifically the consequences of early substance exposure on neurological development.
 
Model 1: Binge-Alcohol Animal Model of Adolescent Substance Use
The aim in this study is to understand the effects of adolescent ethanol on white matter, and the capabilities of diffusion tensor imaging in detecting and quantitating associated changes. We can identify ethanol induced in white matter changes in a rodent model of adolescent binge-alcohol exposure using HARDI. We have employed an animal model that facilitates controlled exposure and high resolution DTI. Additional new approaches to our study include the following:

- Delineate progressive changes in diffusion anisotropy (DA) in an extended rodent model of consisting of binge and chronic alcohol exposure across a developmental continuum.
- Implement the Structured Specific Statistical Mapping (SSSM) fiber track analysis method
- Evaluate the precision of DA measures by comparison to histological findings.

Model 2: Human Adolescent Model of Chronic Marijuana Use The aim in this study is to use diffusion tensor imaging to study structural changes in adolescent ethanol exposure and quantify changes in white matter integrity and organization in human adolescent models of substance abuse. Applying fiber track mapping (FTM) methods, we can identify the structural variations in white matter associated with chronic cannabis use during adolescence. Cannabis in the form of smoked marijuana is the most widely used illicit substance among adolescents in the U.S. Despite the prevalence of heavy marijuana use, it is unclear how protracted use may affect brain structure and function during a period of continued neuromaturation.

Publications

Bava S, Frank LR, McQueeny T, Schweinsburg BC, Schweinsburg AD, Tapert SF. Altered white matter microstructure in adolescent substance users. Psychiatry Res, 173: 228-237, 2009.

Jacobus J, McQueeny T, Bava S, Schweinsburg BC, Frank LR, Yang TT, Tapert SF. White matter integrity in adolescents with histories of binge drinking and marijuana use. Neurotoxicology Teratol, 31: 349-355, 2009.

McQueeny T, Schweinsburg BC, Schweinsburg AD, Jacobus J, Bava S, Frank LR, Tapert SF. Altered white matter integrity in adolescent binge drinkers. Alcohol Clin Exp Res, 33: 1278-1285, 2009.

Bava S, Frank LR, McQueeny T, Schweinsburg AD, & Tapert SF (2008).  White matter integrity in adolescent marijuana users. [abstract]. Journal of the International Neuropsychological Society, 14(S1), 101.