How do you assign a logic brick onto an indivual bone? I am trying to make a simple head turn but there are multiple bones that are part of the object for rigging... every time I try to assign a logic brick in edit mode to only the bone controlling the turn of the head... it assigns it to every bone making the whole body turn.
Blender's logic bricks are attached to an object. An armature is one object that can contain several bones, a simple motion actuator will move the entire armature as one solid object.

To move a single bone you need to create an action, then play the action using an action actuator.