How our brain’s so-called ‘hunger circuit’ governs our eating has been redefined in an unexpected finding, which may have implications for anti-obesity therapies. Physiologist Zachary Knight of the University of California, San Francisco says that using new fiber optic technology that can record brain activity in real time, they found that hungry mice given food became satiated even before they took a bite.

"As soon as the mouse saw or smelled the food, the hunger neurons would shut off, and usually the mouse would look at the food for a few seconds and start eating, but by the time the mouse actually started eating, the entire response was over – so it was as if these hunger neurons were responding to the sensory detection of food alone, and not to its consumption, which was what people would have predicted."

So, how can this someday translate to humans?

"There are a number of drugs that are currently in late-stage clinical trials for the treatment of obesity and we don’t really understand at the neural circuit level, how any of these drugs work. And so the methods that we use to watch the activity of specific neurons is going to allow us to start to understand where these drugs that do work, are acting."