Abstract
The brain requires high amounts of energy for cellular homeostasis and neurological functions. This energy is mainly supplied by the oxidation of glucose, although other substrates may be used in critical situations. The capacity of the brain to conserve energy is illustrated by flow metabolism coupling, and by the separation between functional and basal activity. The evaluation of cerebral metabolism is defined as the assessment of energy substrates availability and utilization. This evaluation may be performed in physiological or pathological conditions, at a regional or at the global level, at rest or during activation processes. The main techniques discussed in this review include monitoring of venous blood in the jugular bulb, cerebral microdialysis, near infrared spectroscopy, cerebral oximetry using microprobe electrodes, positron emission tomography, magnetic resonance and the magnetoencephalography.