Do you believe in gravity?
Well, gravity exists whether or not you believe in it.
The fourth dimension is typically referred to as time. It is the dimension of persistence.
Prayer, on the other hand, has nothing to do with physical reality or any dimensions of the space-time continuum.
Prayer is communication between your spiritual, true self and the Heavenly Father -- the oneness of all, or source of all things.
Most people don't know how to pray. They want one thing, but pray for another, and are disappointed with the results.
Let me give you an example. Someone is suffering from cancer and fears dying from the disease. They offer what they think as a prayer to God for a return to health, but in actual fact, they are presenting a "fear of death" to God. So, they are surprised and dismayed when health does not return.
Prayer needs to be presented with faith, not fear. Faith is also a word too many misunderstand. Faith is not belief. Faith is perfect confidence. Faith is a state of creation (cause), not perception (effect).
Prayer is answered instantaneously. So, if you doubt, you get the result of that doubt -- more status quo. More of the same reality. Prayer isn't what you "think" consciously. It is what you feel sub-consciously.