Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.20.051284v1?rss=1 Authors: Scavuzzo, C. J., Newman, L. A., Gold, P. E., Korol, D. L. Abstract: Peripheral and central administration of glucose potently enhance cognitive functions. The present experiments examined changes in brain extracellular glucose levels while rats were trained to solve hippocampus-sensitive place or striatum-sensitive response learning tasks for food or water reward. During the first minutes of either place or response training, extracellular glucose levels declined in both the hippocampus and striatum, an effect not seen in untrained, rewarded rats. Subsequently, glucose increased in both brain areas under all training conditions, approaching asymptotic levels ~15-25 min into training. Compared to untrained-food controls, training with food reward resulted in significant increases in the hippocampus but not striatum; striatal levels exhibited large increases to food intake in both trained and untrained groups. In the rats trained to find water, glucose levels increased significantly above the values seen in untrained rats in both hippocampus and striatum. The present findings suggest that decreases in glucose early in training might reflect an increase in brain glucose consumption, perhaps triggering increased brain uptake of glucose from blood, as evident in the increases in glucose late in training. Together with past findings measuring lactate levels under the same conditions, the initial decreases in glucose may also stimulate increased production of lactate from astrocytes to support neural metabolism directly and/or to act as a signal to increase blood flow and glucose uptake into the brain. Copy rights belong to original authors. Visit the link for more info