The third eye is not really a part of the physical body. It is part of the second body which is etheric body. Your etheric body is a body which is similar to your physical body over which it is superimposed, it has a corresponding spot in the physical body, but it is not part of it, so far the closest reference scientist discovered on psychical body is the Pineal Gland.
According to Freud, our dreams are a representation of our unconscious desires, thoughts and motivations. Dreams are projection of our repressed desires, buried deep in our subconsciousness, Though, for past many centuries, Tibetan Monks and Indian Yogis have been using Yog Nidra or lucid dreaming to explore in the basement of their subconsciousness, A lucid dream is any dream in which one is aware that one is dreaming and can utilize the extraordinary power of subconsciousness.