Combine turkey, eggplant, salsa, tomato paste, parsley, chili powder, cumin, oregano and corn in slow cooker. Cover and cook on low 5 to 6 hours. Stir with a fork to break up large chunks of turkey. Spoon about 3/4 cup cooked turkey mixture on each pita half. Top with yogurt, lettuce, olives and cheese, if desired.