The first technique, although not found as effective works on keeping the food longer in the stomach by disrupting the natural motility cycle of stomach and there by continuing the satiety.
The second technique is based on the fact that enteric nervous system carries signals to the brain that indicate the state of satiety. By stimulating this nervous system, specifically vagus nerve a gastric pace maker mimics the feeling of satiety to the brain.
This device is implanted using laproscopic surgery. There are also some efforts to implant this device endoscopically avoiding surgery.
It is a technology that is still in the beginning phase and being tested in Europe and Canada and shows great promise. However early evidence suggests that it cannot produce the same reduction in excess weight loss as Bariatric surgery such as Roux-en-Y or Laproscopic Adjustable Gastric Banding (Lap Band)
Medtronic which makes heart pacemakers, is developing this treatment.