Cortical spectroscopy: Localized spectroscopy of the cerebral cortex in rats

A method for obtaining nuclear magnetic resonance (NMR) spectroscopic signals confined to the cerebral cortex in rat using a cortical coil constructed based on the principles of the zig-zag coil is described. We obtained ³¹P NMR spectra of normal cerebral cortex and cold-induced injured cortex using this cortical coil. The cortical coil clearly demonstrated an increase in inorganic phosphate (P(i)) confined to cerebral cortex which, by contrast, the convential planar surface coil failed to detect. There are significant metabolic differences between cortex and subcortical tissues. The technique described here, capable of assessing corrtical metabolism in vivo without contamination by the underlying tissue, has substantial application to studies of cerebral metabolism.