Predominant neuroimmunometabolic homeostasis in the healthy brain and its disruption in neurodegenerative conditions. In the healthy state (left, blue arrows), glucose, amino acid, and lipid metabolism occur in various cell types. Neuroimmunometabolism disrupts this homeostasis (right, red arrows) contributing to degenerative conditions. IDO, Indoleamine-2,3 dioxygenase; PI3K/AKT, phosphoinositide 3-kinases.