Gray Matter and Impairments from Cocaine Abuse
A new study conducted by the United States Department of Energy’s Brookhaven National Laboratory has the distinction of being the first to show a link between structure and function of the brain in healthy people and impairment of the same structure and function in the brain of those addicted to Cocaine. Published in the Journal of Neuroscience, the study discusses the importance of gray brain matter in decision making and thought processing. Apparently the greater the amount of gray matter a person has the better their ability to evaluate rewards and consequences.
It is already known that the brain is divided into gray matter and white matter. Gray matter is made of nerve cell bodies and white matter which makes up the axons that connect the cells. Previous studies have compared gray and white matter in healthy individuals with gray and white matter in persons with neuropsychiatric diseases. The study published in the Journal of Neuroscience compared gray matter in healthy persons with those of drug addicted persons.
To complete this study, researchers used MRI brain scans and measured brain volume in both healthy persons and cocaine users. Subjects also completed a psychological task with electrodes measuring P300 electrical signals attached to their scalps. The task had a potential for monetary reward. In healthy subjects the P300 increased with perceived increase on reward while cocaine users had no difference.
The findings of this study suggest that cocaine addicted persons had less gray matter volume in the region of the brain that controls reward processing. Researchers of this study remarked that, “These structure-function deficits may translate into dysfunctional behaviors in the real world. Specifically, impaired ability to compare rewards, and reduced gray matter in the prefrontal cortex, may culminate in the compromised ability to experience pleasure and to control behavior, especially in high-risk situations -- for example, when craving or under stress -- leading individuals to use drugs despite catastrophic consequences.”
This study can lead to significant understanding about how addiction works and could have positive implications for future treatment.
Image by Thomas Schultz:
Visualization of diffusion tensor imaging data, depicting a detail of an axial slice of a human brain. The visualization uses standard diffusion ellipsoids, colored with the XYZ-RGB principal eigenvector color mapping. Elongated ellipsoids indicate the presence and direction of homogeneous fiber tracts (white matter) within the voxel. Small spherical ellipsoids indicate gray matter, large spherical ellipsoids indicate that some part of the voxel is filled with cerebrospinal fluid (in the black area at the bottom, very large ellipsoids have been masked to avoid occlusions).