Wednesday, March 7, 2007

Looking for the Ghost in the Machine

For centuries scientists and theologians have been butting heads over the explanation of religious or miraculous phenomena. One side of the debate argues that things like visions and related experiences cannot be explained by science and therefore must be evidence of God, and until recently, there was very little means of debating that statement. However, recent findings show that there may be a neurological basis to these fantastic claims. BBC news reported on Ellen White, a woman with temporal lobe epilepsy, who experienced powerful religious visions – a symptom that is relatively common to people with this brain disorder. The studies of Michael Persinger caught the attention of the scientific journal Nature’s news center when he reported controversial findings that experiences like White’s could be replicated by applying magnetic stimulation to the temporal lobes. Whether these findings confirm or disconfirm a physical basis for religion is hazy, but these and similar reports seem to suggest that one way or another, there is some neurological basis for spirituality.

Ellen White’s case is characteristic of patients suffering from temporal lobe epilepsy, a condition in which the patient experiences seizures centralized around the temporal lobes. Aside from localization, temporal lobe epilepsy is distinct from other types of epilepsy in that it causes hyperreligiosity. Sufferers of this disorder tend to experience seizures as “a rapture beside which everything else paled. In the rapture was a clarity, an apprehension of the divine – no categories, no boundaries, just a Oneness with the creator.” (pgs 180-181, Phantoms in the Brain) These cases beg the question – what happens when an atheist has this disorder? BBC’s report included a mention of Rudi Affolter, who, despite being a confirmed atheist, started experiencing seizures around the temporal lobe when he was 43. During his first episode, he had a religious vision in which he was “told [he] had gone [to hell] because [he] had not been a devout Christian, a believer in God.” The article did not mention whether this vision resulted in a change in his faith, but it is common for patients with this disorder to become religious following the onset of symptoms. One survey of a group of epileptic patients examines this trend, along with a review of many studies observing the same trend, and notes that in the cases that religious conversion does not occur, subjects still tend to perceive some sort of mystical delusion (Dewhurst and Beard, 1970). However, exact proportions of the cases observed actually included religious experiences or that resulted in conversion were not included. Professor V. S. Ramachandran, a researcher at UC San Diego and author of Phantoms in the Brain, suggests that the connection between epilepsy of the temporal lobe and spirituality may be due to the presence of existing circuits in the medial temporal lobe that, when selectively activated in a seizure, makes patients more prone to religious belief (BBC, 2003). It has been postulated that this is connected to the left hemisphere’s tendency to fabricate explanations for experiences whose causes lie beneath the threshold of consciousness. The seizures seen in these cases also involve the limbic system, which causes a rush of emotional arousal, and it may be that, lacking any rational explanation for what is happening, the left hemisphere comes up with the only explanation it can find for such an intense experience – a message from God. However, it is unlikely that this exact activity accounts for the majority of religious experiences in healthy people. Neuroimaging studies done on highly spiritual people engaged in religious activity have not shown any activation in the left temporal lobe. A study on nuns in “a state of union with God” showed a large array of activation in nearly a dozen locations throughout the brain, none of which were the left temporal lobe (Beauregard M, 2006), and an fMRI study of people engaged in glossolalia showed activation in the frontal and parietal lobes, as well as the left caudate. Both studies suggest that voluntary religious interactions are more associated with higher brain functions, and not solely the limbic system, nor the same region responsible for such episodes in the epileptic patients.

Ramachandran’s research has shown that even in seizure-free periods, people with temporal lobe epilepsy exhibit physical signs of hyperreligiosity in a way that is distinct even from the devoutly religious that are in good health. In his 2003 study, he examined the galvanic skin response of a set of temporal lobe epileptic and healthy subjects when presented with neutral, sexual, and religious words. The healthy subjects showed increased electrical resistance in the skin, indicative of emotional arousal, when presented with the sexually charged words, while no response was measured for the other two groups. The epileptic patients, on the other hand, exhibited arousal only in response to the religious terms, with decreased response to the other two groups. This data fits in well with the typical persona of patients with this disorder, as there seem to be lasting personality changes as a direct result of the episodes. Personality changes tend to include heightened emotions, perception of cosmic significance in trivial events, and an obsessive preoccupation with theological issues, which is occasionally accompanied by hypergraphia, a tendency to excessive writing, generally on a religious theme. These traits have been attributed to what is now called a “temporal lobe personality,” and they tend to permanently alter the patient’s inner emotional life. While this data does not suggest that being religious is due to a quirk in the brain, it does point to particular networks that make a significant contribution to spirituality.

The role of the temporal lobe in religious experience is also discussed in Nature’s article on Dr. Michael Persinger, whose research on temporal lobe stimulation has caused a good deal of controversy. Persinger said that he experienced God for the first time in his life while stimulating his left temporal lobe using the transcranial magnetic stimulator he had available in his lab. Following the experience, he began running experiments to see if such a response would be observed in others. According to his findings, stimulation of the left temporal lobe caused 80% of his subjects to feel an unexplained presence in the room. The article states that Persinger explained this by stating, “[the] magnetism causes bursts of electrical activity in the temporal lobes of the brain, and he linked this to the spiritual experiences.” However, Persinger’s studies have largely been dismissed, as other researchers were unable to produce the same results. Pehr Granqvist, a Swedish researcher, criticized Persinger’s research by pointing out that his studies were not double-blind – and furthermore, the patients were told beforehand what they might experience as a result of the stimulation. When he ran his own studies on 43 subjects with the double-blind design included, he found that only three people reported any kind of religious experience – and two of them were in the control group. Furthermore, half the subjects who reported more subtle spiritual experiences were in the control group. Granqvist acknowledges that while this is a high level of spiritual experience, it matches what Persinger reported in his control groups. Personality tests were also run to examine the subjects’ spiritual orientation, as well as their susceptibility to suggestion, and researchers found that people with these traits were more likely to experience a supernatural presence. Therefore, Granqvist concluded that these experiences could be predicted by suggestibility, and not by the magnetic stimulation. Persinger responded to the study by saying that the correct calibration of the magnetic field had not been used, and that many of his studies were double-blinded. However, the accounts from subjects, including some prominent psychology researchers, are convincing enough to suggest that regardless of the controversy, Persinger’s methods may have some neurological basis.

Of course, many people don’t need psychological studies to know that there can be a connection between religious experiences and the brain. People have been manipulating their neurochemistry via hallucinogens substances to reach states of higher spiritual awareness for millennia, although it is not a method accepted by most modern religious groups. ABC did a report last December on the findings of a study where psilocybin, the active ingredient in psychedelic mushrooms, was studied as a means of induction of spiritual experiences. Because of the long history of this use of related substances, the researchers were not surprised to find that subjects reported “increased wellbeing and satisfaction with life” a full two months after having taken the substance. This is particularly interesting in regards to the connection between spirituality and the temporal lobe because psilocybin primarily affects the brain’s serotonin system, in particular the 5-HT2A receptor. (Griffiths, 2006) The medial temporal lobe is rich in serotonin receptors, so it’s possible that the drug is interacting directly with the section of the brain that is activated in the temporal lobe seizures. Furthermore, other studies have shown that temporal lobe epilepsy reduces the amount of 5-HT1A receptors, whose primary function is to mediate serotonin activity in the brain. If serotonin levels get high, it’s the job of the 5-HT1A receptors to initiate a negative feedback loop that controls those levels. It stands to reason that epileptic patients might be lacking in the ability to mediate their serotonin activity, which explains portions of the “temporal lobe personality,” and also explains the extreme impact of the overstimulation of the limbic system during temporal lobe seizures. Thus, the psilocybin may have similar interactions with the receptors in that region to those that occur during an epileptic episode, which explains the enhanced spiritual awareness in both states.

The growing field of neurotheology prompts many tricky questions beyond inquiries into the physical basis of these phenomena: Does God exist outside the human mind, or is God a creation of our brains? While these studies can’t directly address either of these questions, they do show us that there is at least neurological support for the basis of spirituality in our culture. Whether this is the product of evolution is unclear, but that’s the case with large portions of culture, and is therefore not indicative of the validity of these findings. One criticism of neurotheology is that it violates the principle of Occam’s razor: the simplest explanation is the correct one, and therefore it’s simpler to conclude that religious experiences began as the product of neurological phenomena, rather than to say that it was built into our brain by some form of intelligent design. However, that is the perspective from an objective observer, and the view from a patient with temporal lobe epilepsy would be dramatically different. There is no explanation in conventional wisdom for what this patient must experience in the midst of their emotional centers being overloaded with activity, and as emotions tend to function without rationality, it may be that this patient is in fact using Occam’s razor to the best of their ability when they conclude that they are touched by the hand of God.