Scalp recorded direct current (DC) potential shifts associated with food intake in hungry humans

In humans, eating is assumed to be regulated within a neuronal circuitry integrating hypothalamic "feeding centers" with neocortical regions. Here, DC potentials were recorded in food deprived men to demonstrate a graded tuning of neocortical excitability in conjunction with meal ingestion. In the beginning of food ingestion a pronounced negative DC potential shift developed (P<0.01) which was replaced by a gradual positive potential shift reaching a maximum within 5 min after cessation of food intake (P<0.05). Both negative and positive shifts showed a widespread cortical distribution. The initial negative DC potential presumably reflecting increased depolarisation of apical cortical dendrites, may serve to facilitate eating behavior. The succeeding positivity points to a growing inhibitory influence on cortical processing with increasing satiety that may support termination of meal intake.