The metabolic events of neuronal energetics during functional activity are still partially unexplained. In particular, lactate (and not glucose) was recently proposed as the main substrate for neurons during activity [Proc Natl Acad Sci USA 91 (1994) 10625]. By means of proton magnetic resonance spectroscopy, lactate was reported to increase during the first minutes of prolonged stimulation [Proc Natl Acad Sci USA 88 (1991) 5829; J Cereb Blood Flow Metab 12 (1992) 584; Magn Reson Med 35 (1996) 143], but the studies reported thus far suffered from low temporal resolution. In the present study we used a time-resolved proton magnetic resonance spectroscopy strategy in order to analyse the evolution of lactate during the early seconds following a brief visual stimulation (event-related design). A significant decrease in lactate concentration was observed 5 s after the stimulation, while a recovering of the baseline was observed at 12 s.
- Functional neuronal metabolism
- Single-voxel NMR spectroscopy