Time-resolved functional 1H MR spectroscopic detection of glutamate concentration changes in the brain during acute heat pain stimulation.

Non-invasive in vivo detection of cortical neurotransmitter concentrations and their changes in the presence of pain may help to better understand the biochemical principles of pain processing in the brain. In the present study acute heat pain related changes of the excitatory neurotransmitter glutamate were investigated in the anterior insular cortex of healthy volunteers by means of time-resolved functional proton magnetic resonance spectroscopy ((1)H-MRS). Dynamic metabolite changes were estimated with a temporal resolution of five seconds by triggering data acquisition to the time course of the cyclic stimulus application. An overall increase of glutamate concentration up to 18% relative to the reference non-stimulus condition was observed during the application of short pain stimuli.