In terms of Brodmann areas, the prefrontal cortex traditionally includes areas 8, 9, 10, 11, 44, 45, 46, and 47 (to complicate matters, not all of these areas are strictly granularâ44 is dysgranular, caudal 11 and orbital 47 are agranular).
A starfish's mouth is on the center of its bottom side. Its stomach  is directly behind the mouth after a short esophagus and extends a  bit down its five arms.
Insert the knife tip into the fish's belly near the anal opening and move the blade up along the belly, cutting to the head. Keep the knife blade shallow so you don't puncture the intestines. Spread the body open and remove all of the entrails, locate the fish's anus and cut this out in a V or notch shape.