Manganese ion enhances T1‐weighted MRI during brain activation: An approach to direct imaging of brain function

@article{Lin1997ManganeseIE,
  title={Manganese ion enhances T1‐weighted MRI during brain activation: An approach to direct imaging of brain function},
  author={Yi-jen Lin and Alan P. Koretsky},
  journal={Magnetic Resonance in Medicine},
  year={1997},
  volume={38}
}
Present techniques for functional MRI rely on detecting changes in hemodynamics that result as a consequence of brain activation. It would be useful if MRI techniques could be developed that enable imaging of a parameter directly related to neuronal activity. Influx of calcium into neurons is necessary for release of neurotransmitters. Divalent manganese ions (Mn2+) can enter cells through voltage‐gated calcium channels and Mn2+ is paramagnetic. Mn2+ accumulation in brain due to activation… 

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References

SHOWING 1-10 OF 48 REFERENCES

Dynamic Magnetic Resonance Imaging of the Rat Brain during Forepaw Stimulation

A magnetic resonance imaging brain mapping method was used to localize an activated volume of brain tissue in chloralose-anesthetized rats during electrical stimulation of the forepaw, which led to an increase in MR signal intensity of the contralateral frontal and parietal cortices, which corresponded to forelimb motor and somatosensory areas.

Multi‐Slice MRI of Rat Brain Perfusion During Amphetamine Stimulation Using Arterial Spin Labeling

It is shown that no signal loss occurs due to MTC effects when the two‐coil system is used for MRI of rat brain perfusion, enabling three‐dimensional perfusion imaging.

Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.

Neuronal activity causes local changes in cerebral blood flow, blood volume, and blood oxygenation. Magnetic resonance imaging (MRI) techniques sensitive to changes in cerebral blood flow and blood

Diffusion weighted fMRI at 1.5 T

Results suggest that the majority of the functional signal at 1.5 T arises from protons that have apparent diffusion coefficients that are approximately four or five times higher than that of brain tissue.

Magnetic resonance imaging of perfusion using spin inversion of arterial water

Perfusion images of a freeze-injured rat brain have been obtained, demonstrating the technique's ability to detect regional abnormalities in perfusion.

Functional Brain Mapping Using Magnetic Resonance Imaging: Signal Changes Accompanying Visual Stimulation

The amplitude, sign, and echo time dependence of these intrinsic signal changes are consistent with the idea that neural activation increases regional cerebral blood flow (rCBF) with a concomitant increase in venous blood oxygenation.

The intravascular contribution to fmri signal change: monte carlo modeling and diffusion‐weighted studies in vivo

The model and experimental results are in agreement and suggest that the intravascular spins account for the majority of fMRI signal change on T2*‐weighted images at 1.5 T.