Brain lactate responses during visual stimulation in fasting and hyperglycemic subjects: A proton magnetic resonance spectroscopy study at 1.5 Tesla

Maddock, Richard J.; Buonocore, Michael H.; Lavoie, Shawn P.; Copeland, Linda E.; Kile, Shawn J.; Richards, Anne L.; Ryan, John M.

doi:10.1016/j.pscychresns.2006.02.004

« Previous Next »Psychiatry Research: Neuroimaging
Volume 148, Issue 1 , Pages 47-54, 22 November 2006

Brain lactate responses during visual stimulation in fasting and hyperglycemic subjects: A proton magnetic resonance spectroscopy study at 1.5 Tesla

Richard J. Maddock
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Sacramento, CA, USA
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
- Corresponding author. Imaging Research Center, UC Davis Medical Center, 4701 X Street, Sacramento, CA 95817, USA. Tel.: +1 916 734 3286; fax: +1 916 734 8750.
Michael H. Buonocore
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
- Department of Radiology, University of California Davis, Sacramento, CA, USA
Shawn P. Lavoie
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Sacramento, CA, USA
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
Linda E. Copeland
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Sacramento, CA, USA
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
Shawn J. Kile
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Sacramento, CA, USA
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
Anne L. Richards
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Sacramento, CA, USA
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
John M. Ryan
- Imaging Research Center, University of California Davis, Sacramento, CA, USA
- Department of Radiology, University of California Davis, Sacramento, CA, USA

Received 30 November 2005; received in revised form 24 January 2006; accepted 20 February 2006.

Abstract

Proton magnetic resonance spectroscopy (¹H-MRS) studies showing increased lactate during neural activation support a broader role for lactate in brain energy metabolism than was traditionally recognized. Proton MRS measures of brain lactate responses have been used to study regional brain metabolism in clinical populations. This study examined whether variations in blood glucose influence the lactate response to visual stimulation in the visual cortex. Six subjects were scanned twice, receiving either saline or 21% glucose intravenously. Using ¹H-MRS at 1.5 Tesla with a long echo time (TE=288ms), the lactate doublet was visible at 1.32ppm in the visual cortex of all subjects. Lactate increased significantly from resting to visual stimulation. Hyperglycemia had no effect on this increase. The order of the slice-selective gradients for defining the spectroscopy voxel had a pronounced effect on the extent of contamination by signal originating outside the voxel. The results of this preliminary study demonstrate a method for observing a consistent activity-stimulated increase in brain lactate at 1.5 T and show that variations in blood glucose across the normal range have little effect on this response.