These results have been supported by other evidence suggesting a reduction in FA of the corpus callosum and internal capsule of cocaine users, with the reduction correlating with impulsivity as measured by the BIS (Lim et al., 2002, 2008). Animal data suggest that the lower FA may be related to cocaine use. Narayana and colleagues (2009) administered cocaine or saline chronically via an osmotic minipump to rats. The cocaine-treated rodents were found to have significantly lower FA and radial diffusivity in the splenium of the corpus callosum compared to saline-treated rats. The cocaine-treated rats also had lower myelin basic protein and higher neurofilaments compared to saline-treated rats. Therefore, at least some of the DTI-related changes in white matter seen in cocaine users may be because of chronic cocaine administration.
