Vagally Understood / Interactive model

Current flow through the tragus

A slice through the tragus with a stimulating electrode on each side. Each pulse drives current from one pad to the other through skin, subcutis and cartilage. Change the pulse, the pads or the skin contact and watch where the current goes, what voltage it takes, and which nerve fibres feel it.

New to this? How tVNS works shows the same physics on a 3D ear wearing the Vagal Oh! clip. How much current crosses straight through depends on the shape of the tragus: about 95% in this simpler tragus, and about 80% in the 3D ear, whose tragus joins the cheek along a broader base. The voltage limit starts at 60 V, as on our stimulators.