C. G. Jung calls initial religious experience Numinosum and maintains that organised religious confessions, rituals and dogmas are secondary. Numinosa, Jung writes, can be so powerful that they will destroy the experiencer if he or she does not have the adequate religious frame to encapsulate the Numinosum. If such a frame is not available, the experiencer, according to Jung, may become mentally deranged (Anne L. C. Runehov, A Neuro-psychological Explanation of Religious Experience).
So, religious belief seems to be based in the right hemisphere and the explanation and rational defense for the belief is based in the left hemisphere. So what happens if the connection between the two hemispheres is cut?
Michael Gazzaniga, founder of the Centers for Cognitive Neuroscience at the University of California, Davis and at Dartmouth College, the Neuroscience Institute, and the Journal of Cognitive Neuroscience, describes in the next two videos what happens when the connection between the two hemispheres is lost.
In the next video, Vilayanur S. Ramachandran, the Director of the Center for Brain and Cognition at the University of California, San Diego, describes a case where in one individual is found both a belief and non-belief in God. The right hemisphere of his brain is a theist and the left one is an atheist.
These studies, of course, do not prove either the existence or non-existence of god(s) but I think they are fascinating. They give us insight into the nature of faith and reason.
Anne L. C. Runehov, Sacred or Neural?: The Potential of Neuroscience to Explain Religious Experience (2007).
R. Joseph, The Right Brain and the Unconscious: Discovering the Stranger Within (1992).