Activating the dorsolateral prefrontal cortex can decelerate heart rate through the vagal pathway.

“if you activate dorsolateral prefrontal cortex using what's called transcranial magnetic stimulation... This is a procedure where you take a stimulator, and you non-invasively place it on the skull outside and just above dorsolateral prefrontal cortex, and you stimulate through the skull dorsolateral prefrontal cortex. You observe, as you would expect, a deceleration of heart rate. And it's known to be carried through this vagal pathway, to the sinoatrial node.”