Using datasets from neurosurgery patients and patients with brain damage, the researchers mapped the locations of lesions associated with spiritual and religious beliefs on a specific human brain circuit.
More than 80% of the people in the world consider themselves religious or spiritual. But research on the neurosciences of spirituality and religiosity has been scarce. Previous studies have used functional neuroimaging, in which an individual undergoes a brain scan while performing a task to see which areas of the brain light up. But these correlative studies have given an uneven and often inconsistent picture of spirituality. A new study by researchers from Brigham and Women’s Hospital takes a new approach to mapping spirituality and religiosity and finds that spiritual acceptance can be localized in a specific brain circuit. This brain circuit is centered in the periaqueductal gray (PAG), a region of the brainstem that has been involved in many functions, including fear conditioning, pain modulation, altruistic behaviors, and unconditional love. The team’s findings are published in Biological Psychiatry.
“Our results suggest that spirituality and religiosity are rooted in fundamental neurobiological dynamics and deeply embedded in our neuro-tissue,” said the corresponding author. Michael Ferguson, PhD, a senior researcher from Brigham’s Brain Circuit Therapy Center. “We were amazed to find that this brain circuit for spirituality is centered in one of the most well-preserved brain structures in evolution.”
To conduct their study, Ferguson and his colleagues used a technique called lesion network mapping that allows researchers to map complex human behaviors to specific brain circuits based on the location of brain damage in patients. The team took advantage of a previously published data set that included 88 neurosurgery patients who were undergoing surgery to remove a brain tumor. The locations of the lesions were distributed throughout the brain. Patients responded to a survey that included questions about spiritual acceptance before and after surgery. The team validated their results using a second dataset of more than 100 patients with injuries from combat-penetrating head trauma during the Vietnam War. These participants also completed questionnaires that included questions about religiosity (such as “Do you consider yourself a religious person? Yes or No?”).
Of the 88 neurosurgery patients, 30 showed a decrease in self-reported spiritual belief before and after neurosurgical resection of a brain tumor, 29 showed an increase and 29 showed no change. Using lesion network mapping, the team found that self-reported spirituality corresponded to a specific brain circuitry centered on the PAG. The circuit included positive nodes and negative nodes – lesions that disrupted those respective nodes decreased or increased self-reported spiritual beliefs. The religiousness results of the second data set correspond to these findings. Additionally, in a review of the literature, researchers found several case reports of patients who became hyper-religious after suffering brain damage affecting negative nodes in the circuit.
The locations of lesions associated with other neurological and psychiatric symptoms have also crossed the circuit of spirituality. Specifically, lesions causing parkinsonism overlapped with positive areas of the circuit, as did lesions associated with decreased spirituality. Lesions causing delirium and foreign limb syndrome intersected negative regions, associated with increased spirituality and religiosity.
“It is important to note that these overlaps can be useful in understanding shared characteristics and associations, but these results should not be over-interpreted,” Ferguson said. “For example, our results do not imply that religion is an illusion, that historical religious figures suffered from Foreign Limb Syndrome, or that Parkinson’s disease occurs due to a lack of religious faith. in a part of our brain that is involved in many important functions. “
The authors note that the datasets they used do not provide rich information about patient education, which may influence spiritual beliefs, and that patients in both datasets were drawn from predominantly Christian cultures. To understand the generalizability of their results, they would need to replicate their study in many contexts. The team is also interested in disentangling religiosity and spirituality to understand the brain circuits that can be at the origin of the differences. Additionally, Ferguson would like to pursue clinical and translational applications of the findings, including understanding the role that spirituality and compassion can have in clinical treatment.
“It is only recently that medicine and spirituality have been separated from each other. There seems to be this enduring union between healing and spirituality across cultures and civilizations,” Ferguson said. “I am interested in the extent to which our understanding of brain circuitry might help formulate scientifically sound and clinically translatable questions about how healing and spirituality can inform each other.”
Ferguson MA, Schaper FLWVJ, Cohen A, et al. A neural circuit for spirituality and religiosity derived from patients with brain damage. Biological Psychiatry. 2021; 0 (0). do I:10.1016 / j.biopsych.2021.06.016
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