Brain work: function, metabolism and blood flow.

The "brain work" is characterized by an input which is the processing of sensory information and by an output consisting in the production of ideo-motor activities. This work is performed through electrochemical mechanisms. These biologic mechanisms are strictly dependent on the continuous arrival at regional level of sufficient amounts of glucose and oxygen through blood flow. In fact the regional level of function determines the amount of blood flow and therefore of substrates to that region. This close relationship, function-blood flow-metabolism, permits the study of the cerebral function at any of these three levels. Neurophysiologists recording neuronal firing and clinicians assessing regional levels of blood flow and metabolism activities are seeing very specular aspects of cerebral physiology. The application to the human being of the techniques for regional quantitation of blood flow and of glucose (or oxygen) consumption offers to physiologists and clinicians a new possibility for understanding cerebral functioning both in health and disease.