Neurotheology: The brain and religious experience

The word, neurotheology, was first used in 1962 by Aldous Huxley in his novel, Island. In his book, Huxley described a society that integrated Western science with Eastern philosophy to create a peaceful, enlightened civilization. The current scientific field of neurotheology examines the relationships between the brain and religious experiences.  This endeavor has been controversial, and the term itself has been seen as something of an oxymoron. Employing the “hard sciences” of neurophysiology and neurochemistry to explain the origins of unquantifiable religious experiences seems a futile attempt to capture a ”ghost in the machine.”  On the other hand, characterizing a spiritual experience as one more product of brain activity seems to diminish and explain away the transcendent quality of experiencing the Divine. Nonetheless, in the time since Huxley coined the word in a book of fiction, neurotheology has been the subject of more than 3000 scientific books and papers.

Although neurotheology has only recently emerged as bona fide scientific pursuit, it is commonly seen as having origins in the late 19th century work of the American psychologist and philosopher, William James. In sections of his classic 1902 publication, Varieties of Religious Experience, James explored how hallucinations, seizures, fevers, prolonged fasting, and intoxication can lead to tangible, unshakeable, and life-changing experiences of the Divine. He surmised that some of the stories fundamental to the world’s great religions may have had origins in altered states of consciousness. The beyond-normal experiences of religious figures, such as Jesus being tempted by Satan after 40 days of fasting in the desert, and Siddhartha Gautama, the soon to be Buddha, being tempted by the demon Mara as he meditated under the bodhi tree without food or sleep, led James to suspect those experiences may have arisen from altered brain activity. Both fasting and sleep deprivation are known to induce hallucinations and altered states of consciousness. The vision quest, a ritual of Native American cultures intended to reveal the Great Spirit, includes isolation, sleep deprivation, and days of fasting, all of which alter ordinary perceptions of reality.

Plants such as peyote cactus, psilocybe mushrooms, and  ayahuasca vine that contain psychedelic molecules have long been used by natives of the Americas to induce religious experiences. The League for Spiritual Discovery, founded in 1966 by controversial Harvard psychologist Timothy Leary, advocated for the legal use of lysergic acid diethylamide for meditation and spiritual understanding. It adopted the drug’s acronym, LSD, for its name. Those mind-altering substances are known to act primarily at a specific type of serotonin receptor in the brain, the 5-HT2A receptor. Some have even suggested that the 5-HT2A active molecule, dimethyltryptamine, in the smoke of a burning Acacia bush may have intoxicated Moses when he heard the voice of God speaking to him from amidst the flames. However, while the plant does contain dimethyltryptamine, there is  doubt that sufficient amounts of the drug could have been inhaled while standing close to the plant as it burned.

Neuroscience informs us that naturally occurring alterations in brain activity can induce religious experiences. Seizures in the temporal lobe of the brain, referred to as partial complex seizures, can produce the experience of hearing, seeing, or feeling the strong presence of God.  Such experiences are reported by 1 to 3% of sufferers of that type of seizure. Profound religious experiences may also arise in certain forms of mental illnesses. A common sign of mania in Bipolar Affective Disorder is hyper-religiosity, with  intense feelings of being directed by God or hearing God’s voice.  It is not unusual for schizophrenics to “hear the voice of God” or feel themselves to be in communion with spirits. Shamans, who exhibit many behaviors suggestive of schizophrenia, have long been seen by more primitive societies as oracles of the Gods. Some may refuse to accept that experiences born of altered states of consciousness could have genuine spiritual value. However, one could see altered state of consciousness as freeing the mind of the everyday logic and  petty habits of thought that prevent us from seeing profound religious truths.  Of note, James did convey his impression that altered states of consciousness are neither necessary nor sufficient for religious experiences. 

While many studies have been performed to determine how altered brain activity can facilitate religious experiences, the most recent studies in neurotheology have explored how religious practice can affect the brain. It has long been known that strong religious faith can lessen the likelihood of developing anxiety or depression. However, evidence shows that faith can alter brain activity in specific, measurable ways, including alterations in the structure of the brain. Activity in the right dorsolateral prefrontal cortex of the brain is diminished in individuals suffering depression, particularly in forms accompanied by anxiety and agitation. However, a PET scan study showed that reciting Psalm 23, “The Lord is my shepherd . . .”, but not mere nursery rhymes, caused activation in that area of the brain.  An MRI study showed that those who have long embraced two fundamental tenets of the major religions, altruism and love of neighbor, had increased thickness of gray matter in a circuit of the brain called the Ventral Frontotemporal Network. Such anatomical change is associated with decrease in the likelihood of suffering Major Depression. Buddhist meditation techniques also alter the brain. Functional MRI studies have shown that meditation reduces activity in the brain circuit called the Default Mode Network. Activity in that network is associated with self-involvement, brooding, anxiety, and depression.  Neuroanatomical studies have also shown that experienced meditators have increased white and gray matter volumes in areas of the brain associated with calmness and emotional stability.

Giving thanks to God in prayer is often considered a fundamental part of daily religious practice. Neuroimaging studies have identified a “gratitude network” in the brain involving areas associated with contentment and well-being. These areas include the medial prefrontal cortex, anterior cingulate cortex, and ventral striatum. The habit of giving thanks to God  increases activity and connectivity within this network. Prayers of thanks also decrease activity in the amygdala, a part of the brain that recognizes and responds to threat. There is  downregulation of networks in the brain that participate in the stress response and increases in calming tone of the vagus nerve. It must be said, however, that such expression of gratitude need not be directed toward God or any divine entity. Recurring thoughts and expressions of gratitude toward those who have been kind to us in our lives produce similar effects. Thus, “an attitude of gratitude” itself is healing. It is worth noting that in his journal and diary turned famous book, Meditations, the Roman Emperor and philosopher Marcus Aurelius filled the first pages with expressions of gratitude to his parents, teachers, and mentors that loved hm, taught him, and helped him form his views on life.  

It is now certain that certain types of brain activity predispose to religious experience, and that religious practice can produce helpful changes in the structure and activity of the brain. Might it someday be possible to create a drug or technique of deep brain electrical stimulation that predictably and reliably leads to the experience of God? May certain prayers or religious practices be found that produce mental health and peace of mind more reliably than others? Are certain states of mind more conducive than others in “finding” God? Is God best found in the joy of the view from a mountain top; in the peaceful solitude of a green forest; or in suffering, as Leonard Cohen alluded to in the poetry of his song, Suzanne:

“And when He knew for certain only drowning men could see Him

He said all men will be sailors then until the sea shall free them.”

Or is there deeper wisdom in the Dua Jawshan Kabir prayer of Shia Islam in which the 1,000 different  names and attributes of God are spoken, or in the Hindu notion of Brahman, who is formless but manifests in an endless variety of forms to help humans connect with the divine.

 Unanswered questions remain, and studies in neurotheology continue.