Gastric neurons in the nucleus tractus solitarius are selective to the orientation of gastric electrical stimulation
Objective. Gastric electrical stimulation (GES) is a bioelectric intervention for gastroparesis,
obesity, and other functional gastrointestinal disorders. In a potential mechanism of action, GES
activates the nerve endings of vagal afferent neurons and induces the vago-vagal reflex through the
nucleus tractus solitarius (NTS) in the brainstem. However, it is unclear where and how to stimulate
in order to optimize the vagal afferent responses. Approach. To address this question with
electrophysiology in rats, we applied mild electrical currents to two serosal targets on the distal
forestomach with dense distributions of vagal intramuscular arrays (IMAs) that innervated the
circular and longitudinal smooth muscle layers. During stimulation, we recorded single and
multi-unit responses from gastric neurons in NTS and evaluated how the recorded responses depended
on the stimulus orientation and amplitude. Main results. We found that NTS responses were highly
sel...