how to make a gui element light up when hovering over an object?

Hello, I am working on a project where I have a menu on the side and a scene with objects. What I am trying to do is that when I hover over an object the menu item (GUI) lights up…
How would I go about that ?
Thanks

Attach a script and a collider to your object. In the script implement the OnMouseEnter and OnMouseExit functions to turn your highlight on and off.