Elsevier

Neuroscience Letters

Volume 475, Issue 3, 21 May 2010, Pages 161-164
Neuroscience Letters

Diffusion tensor imaging in studying white matter complexity: A gap junction hypothesis

https://doi.org/10.1016/j.neulet.2010.03.070Get rights and content

Abstract

The role of the prefrontal cortex as an executive oversight of posterior brain regions raises the question of the extent to which the anterior regions of the brain interconnect with the posterior regions. The aim of this study is to test the complexity of rostral white matter tracts, which connect anterior and posterior brain regions, in comparison to caudal white matter tracts and the corpus callosum. Diffusion tensor imaging (DTI) is a modality that measures fractional anisotropy (FA). Higher white matter complexity could result in a decrease of FA, possibly through denser intersection of fiber tracts. DTI was used to determine regional FA in 9 healthy bonnet macaques (Macaca radiata). Four regions of interest were included: anterior and posterior limbs of the internal capsule, the occipital lobe white matter, and the corpus callosum. FA of the anterior limbs of the internal capsule was lowest compared to all other regions of interest (Newman–Keuls (N–K); p < 0.0001), whereas FA of the corpus callosum was highest (N–K; p < 0.0001). The posterior limbs of the internal capsule and the occipital white matter were not distinguishable but exhibited intermediate FA in comparison to the former (N–K; p < 0.0001) and the latter (N–K; p < 0.0001). The current study demonstrates that FA, a measure of white matter complexity, can vary markedly as a function of region of interest. Moreover, validation of these findings using neurohistological studies and replication in human samples appears warranted.

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Acknowledgements

Many thanks to Dr Bruce Sharf, Douglas Rosenblum, Shirne Baptiste, and Ann Marie Lacobelle for their invaluable technical experience. Supported in part by funding from NIMH grant R21MH066748 (JDC), and Independent Investigator NARSAD award (JDC). Dr Coplan receives grant support from Glaxo-Smith-Kline and Pfizer pharmaceuticals, and he is on the Pfizer advisory board and gives talks for BMS, AstraZeneca, GlaxoSmithKline, and Pfizer. Dr. Gorman is an employee of Comprehensive NeuroScience, Inc.,

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