Evoked 23NA MR imaging of sodium currents in the brain
First Claim
1. A method for measuring neuronal activity in a subject'"'"'s brain, said method comprising the steps of:
- a) causing said subject'"'"'s brain to generate neuronal activity;
b) imaging sodium concentration in a portion of said brain using a nuclear magnetic resonance imaging (MRI) apparatus, said apparatus being adapted to produce sodium magnetic resonance images, wherein said magnetic resonance image is primarily a measure of the momentary extracellular sodium concentration in said portion of the subject'"'"'s brain;
c) repeating said step of imaging a plurality of times after said step of causing said subject to produce neuronal activity, wherein, a plurality of said images are produced following the generation of said neuronal activity;
d) displaying said plurality of magnetic resonance images; and
e) measuring neuronal activity from the location of changes in the sodium concentration between successive magnetic resonance images which correlates with the location of said neuronal activity in the brain.
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Abstract
A system and method of Evoked Sodium Magnetic Resonance Imaging (ESMRI) for three-dimensional localization and measurement of sodium currents in the brain during neuronal activity is disclosed. The system measures neuronal activity in response to a stimulus. The sodium MRI measures changes in the sodium concentration due to the influx of sodium into neurons during the generation of synaptic and action potentials. The system measures primarily extracellular sodium which is distinguished from intracellular sodium on the basis of different spin-spin relaxation rates (T2) for these two compartments. Repeated measurements of sodium concentrations are used to produce and display the changes in concentration cinematically. The technique of the present invention is noninvasive and produces three-dimensional brain images with sufficient spatial and temporal resolution to allow three-dimensional visualization of the sequence of neuronal activation in the brain during processing of sensory, motor, cognitive and other tasks.
101 Citations
23 Claims
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1. A method for measuring neuronal activity in a subject'"'"'s brain, said method comprising the steps of:
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a) causing said subject'"'"'s brain to generate neuronal activity; b) imaging sodium concentration in a portion of said brain using a nuclear magnetic resonance imaging (MRI) apparatus, said apparatus being adapted to produce sodium magnetic resonance images, wherein said magnetic resonance image is primarily a measure of the momentary extracellular sodium concentration in said portion of the subject'"'"'s brain; c) repeating said step of imaging a plurality of times after said step of causing said subject to produce neuronal activity, wherein, a plurality of said images are produced following the generation of said neuronal activity; d) displaying said plurality of magnetic resonance images; and e) measuring neuronal activity from the location of changes in the sodium concentration between successive magnetic resonance images which correlates with the location of said neuronal activity in the brain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for measuring neuronal activity in a subject'"'"'s brain, said system comprising:
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means for causing said subject'"'"'s brain to produce neuronal activity; nuclear magnetic resonance imaging (MRI) means, for producing sodium magnetic resonance images, wherein said magnetic resonance images are primarily a measure of the momentary extracellular sodium concentration in said portion of the subject'"'"'s brain; host computer for controlling said MRI means to generate a temporal sequence of said images; means for displaying said plurality of MRI images; and means for measuring neuronal activity from the location of changes in the sodium concentration between successive images which correlates with the location of neuronal activity produced by said means for said subject to produce neuronal activity. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A system for measuring neuronal activity in a subject'"'"'s brain, said system comprising:
- means for stimulating said subject'"'"'s brain to produce neuronal activity;
nuclear magnetic resonance imaging (MRI) means for producing sodium magnetic resonance images, wherein said magnetic resonance images are primarily a measure of the momentary extracellular sodium concentration in said portion of the subject'"'"'s brain; host computer means for controlling said MRI means to generate a plurality of said images, each of said images comprising the T2 echo from said sodium; means for displaying said plurality of MRI images; and means for measuring neuronal activity from the location of changes in the sodium concentration between successive images which correlates with the location of neuronal activity produced by said means for stimulating said subject to produce neuronal activity.
- means for stimulating said subject'"'"'s brain to produce neuronal activity;
Specification