Can I suggest that you make these functions (which you have not included in the code posted), into one function with a parameter for the line to be highlighted.
Menu_Line1_Highlighted();
Menu_Line2_Not_Highlighted();
Menu_Line3_Not_Highlighted();
Menu_Line4_Not_Highlighted();
perhaps
Menu_Line_Highlighted(1);
There is no need to indicate those that should not be highlighted as, by definition, there will only be one line highlighted at any one time.
I am not sure what else you intend to do in the Main_Menu_Case_Switch() function but as you will see, the case number equates to the menu line to be highlighted, so you could eliminate the switch/case structure as it currently stands and substitute a single call to Menu_Line_Highlighted(UP_DOWN_Selector).