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Cocaine-induced brain activation detected by dynamic manganese-enhanced magnetic resonance imaging (MEMRI)

Lu, Hanbing, Xi, Zheng-Xiong, Gitajn, Leah, Rea, William, Yang, Yihong, Stein, Elliot A.
Proceedings of the National Academy of Sciences of the United States of America 2007 v.104 no.7 pp. 2489-2494
antagonists, brain, calcium channels, cocaine, dose response, drugs, hemodynamics, magnetic resonance imaging, manganese, neurons, rats
Dynamic manganese-enhanced magnetic resonance imaging (MEMRI) detects neuronal activity based on the passage of Mn²⁺ into active neurons. Because this mechanism is independent of any hemodynamic response, it is potentially ideal for pharmacological studies and was applied to investigate the acute CNS effects of cocaine in the rat. Dose-dependent, region-specific MEMRI signals were seen mostly in cortical and subcortical mesocorticolimbic structures. To verify the spatial accuracy and physiological mechanisms of MEMRI, neuronal activation following electrical forepaw stimulation revealed somatotopic signal enhancement in the primary and secondary somatosensory cortices, which was blocked by diltiazem, a Ca²⁺ channel antagonist. These data suggest that MEMRI may serve as a tool for investigating the effects of pharmacological agents and opens an application of MRI to study CNS drug effects at a systems level.