The lecture will start by presenting some basic principles of cerebral energy metabolism, including a discussion of the processes behind the very high energy cost of brain activity. This will be followed by a discussion of the central role of glia in the molecular and cellular mechanisms underlying the coupling between synaptic activity, local blood flow and glucose consumption, and hence in the production of signals detected by functional brain imaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET). The results obtained by fMRI and PET in the course of neuropsychiatric diseases such as Alzheimer's disease, depression, schizophrenia or epilepsy will be reviewed and discussed in relation to the cellular and molecular origin of the signals detected by these techniques. Finally, cerebral metabolism as revealed by imaging techniques will be discussed in relation to the energy cost of conscious and unconscious mental processes
