Menu.cs

using UnityEngine;
using System.Collections;

public class Menu : MonoBehaviour
{
    public MenuItem[] menuItems;

    public int selectedMenuItem;

    public bool isVerticalAtExtent = false;

    void Awake()
    {
        menuItems[selectedMenuItem].ToggleHighlight(true);
    }

    void Update()
    {
        float vertical = Input.GetAxisRaw("Vertical");
        if (isVerticalAtExtent && Mathf.Abs(vertical) < 0.5f)
        {
            isVerticalAtExtent = false;
        }
        else if (Mathf.Abs(vertical) > 0.75f && !isVerticalAtExtent)
        {
            isVerticalAtExtent = true;

            menuItems[selectedMenuItem].ToggleHighlight(false);

            selectedMenuItem += (int)Mathf.Sign(vertical) * -1;

            if (selectedMenuItem >= menuItems.Length)
            {
                selectedMenuItem = 0;
            }
            else if (selectedMenuItem < 0)
            {
                selectedMenuItem = menuItems.Length-1;
            }

            menuItems[selectedMenuItem].ToggleHighlight(true);
        }
    }
}