A neural stroke was a hand-to-hand combat technique unique to the Scorvian race.
It involved rising up to full height with a hand stretched up and two fingers pointed down at the intended target and then a quick strike down to the chest which instantly incapacitated the opponent.
This move was so distinct to the Scorvian race that it revealed Matala's true identity to Aeryn Sun when Matala used it on her out of frustration during their workout in the cargo hold.
John Crichton saw the technique used several times in the "time skips" he experienced including a variation used on Ka D'Argo that went from the initial move to a lethal neck snap instead of the usual chest strike. ("Back and Back and Back to the Future")