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The neural substrates of religious experience (saver & rabin 1997)

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The neural substrates of religious experience (saver & rabin 1997)

  1. 1. The Neural Substrates of Religious Experience Jeffrey L. Saver, M.D. John Rabin, M.D.Religious experience is brain-based, like all human R eligious experience is brain-based. This should be taken as an unexceptional claim. All human experi-experience. Clues to the neural substrates of relig- ence is brain-based, including scientific reasoning,ious-numinous experience may be gleaned from mathematical deduction, moral judgment, and artistictern porolimbic epilepsy, near-death experiences, creation, as well as religious states of mind. Determiningand hallucinogen ingestion. These brain disorders the neural substrates of any of these states does notand conditions may produce depersonalization, automatically lessen or demean their spiritual signifi-derealization, ecstasy, a sense of timelessness and cance.1 The external reality of religious percepts is nei- ther confirmed nor disconfirmed by establishing brainspaceless ness, and other experiences that foster correlates of religious experience. Indeed, it has beenreligious-numinous interpretation. Religious argued that demonstrating the existence of a neuraldelusions are an important subtype of delusional apparatus sustaining religious experience can reinforceexperience in schizophrenia, and mood-congruent belief because it provides evidence that a higher powerreligious delusions are a feature of mania and has so constructed humans as to possess the capacity todepression. The authors suggest a limbic marker experience the divine.2 For the behavioral neurologisthypothesis for religious-mystical experience. The and neuropsychiatrist, the challenge is to delineate the distinctive neural substrates of religious experience andtern porolimbic system tags certain encounters with their alteration in brain disorders. external or internal stimuli as depersonalized, de- Investigation of the neural ground of religious expe- realized, crucially important, harmonious, and/or rience is hampered by the absence of a widely acceptedjoyous, prompting comprehension of these experi- animal correlate that would allow laboratory experi- ences within a religious framework. mentation. Evidence with neuroanatomic import is (The Journal of Neuropsychiatry and Clinical largely derived from clinical observations in patientsNeurosciences 1997; 9:498-510) with focal brain lesions, especially epileptic disorders, and much of this is anecdotal. We will review data that have been collected on religious experience in normal individuals and in different neurologic and neuropsy- chiatric syndromes. From this scattered literature, a pre- From UCLA-Reed Neurologic Research Center, 710 Westwood Plaza, Los Angeles, CA 90095. Send correspondence to Dr. Saver at the above address. Copyright © 1997 American Psychiatric Press, Inc.498 VOLUME 9 #{149} NUMBER 3 #{149} SUMMER 1997
  2. 2. SAVER AND RABINliminary unifying model of the brain basis of religious that perception of the divine occurs not through theexperience may be constructed. operation of a distinctive sensory faculty, but through the superimposition upon ordinary sensations of a unique numinous-mystical feeling, a feeling of directCIRCUMSCRIPTION OF THE TOPIC awareness of a sacred or divine presence.8’9 Studies of healthy individuals and neuropsychiatric populationsMost religious experience parallels ordinary experience. support this hypothesis and suggest a distinctiveThe religious sentiments include religious joy, religious neurolimbic substrate.love, religious fear, and religious awe. These religiousemotions are analogues of ordinary emotions of joy,love, fear, and awe, differing not in their emotional RELIGIOUS EXPERIENCE INtone, but only in being directed to a religious object. NORMAL INDIVIDUALSTheir neural substrate is likely to contain nothing of aspecifically religious nature, but instead to rest upon the Surveys suggest that religious-numinous experiencessame limbic and subcortical networks that support non- are common in both children and adults, across differ-religious joy, love, fear, and awe, directed by dorsolat- ent historical eras, and across all cultures. #{176}‘ In nationaleral and orbital frontal cortices to religious rather than surveys in the United States, Britain, and Australia, 20%nonreligious targets. The neural substrates of human to 49% of individuals report having personally hademotionality have been extensively delineated.34 numinous experiences, and this figure rises to more Similarly, religious language depends upon the cus- than 60% when in-depth interviews of randomly se-tomary dominant-hemisphere perisylvian language lected individuals are conducted.8 Hardy and his col-cortices for its production, differing only in taking sa- leagues8’6 identified eight major types of numinouscred rather than nonsacred topics as linguistic themes. experience in British individuals, encompassing, in de-Focal left-hemisphere lesions produce aphasia for relig- scending order of frequency, 1) a patterning of eventsious discourse that parallels aphasia for nonreligious in a person’s life that convinces him or her that in somediscourse, as common clinical experience attests. Pros- strange way they were meant to happen, 2) an aware-ody and other emotional contributions to discourse of ness of the presence of God, 3) an awareness of receivingthe right hemisphere apply to both religious and non- help in answer to a prayer, 4) an awareness of beingreligious themes, and nondominant-hemisphere looked after or guided by a presence not called God, 5)lesions have been reported to produce parallel impair- an awareness of being in the presence of someone whoments of religious and nonreligious emotional process- has died, 6) an awareness of a sacred presence in nature,ing.5 Similarly, scholastic/talmudic reasoning is 7) an awareness of an evil presence, and 8) experiencingordinary reasoning applied to religious problems and is in an extraordinary way that all things are “One.” Stud-undoubtedly mediated by the same neural networks in ies in identical and fraternal twin pairs raised apartfrontal and parietal multimodal association areas. suggest that genetic factors account for 50% of interim- A first general observation, then, is that the neural dividual variance in religious interests and attitudes.’7substrate for the preponderance of religious affect and The cross-cultural ubiquity of numinous experiencescognition is the whole human brain, employing proc- and the heritability of religious dispositions argueessing that is parallel, distributed, affective, and sym- strongly for a biologic basis, but fail to indicate thebolic, with contributions of large-scale neurocognitive specific neural mechanisms involved. Clues to neuralnetworks subspecialized for linguistic, prosodic, logical, substrate must be gleaned from the sites of brain disor-and affective processing. ders that provoke qualitatively similar experiences. What might be peculiarly distinctive to religious ex-perience would appear, on first inspection, to reside notin the domains of affect, language, or cognition, but in EPILEPSY AND RELIGIOUS EXPERIENCEperception. It is the direct sensory awareness of God orthe divine that is a quintessential mark of specifically Humanity has long recognized a direct link betweenreligious experience. There is, however, no identifiable epilepsy and the divine. The early Greeks viewed epi-separate organ of religious perception. Accordingly, lepsy as a “sacred disease,” a visitation from the gods,sensory apprehension of the divine is likely to be medi- until the notion of divine genesis of seizures was dis-ated, at least in part, by the neural systems for ordinary pelled by Hippocrates.18 In the Medieval and early Ren-tactile, visual, auditory, and olfactory perception. Wil- aissance periods, wide currency was given the biblicalliam James and others have suggested, and we concur, view that epileptic seizures are manifestations of de-JOURNAL OF NEUROPSYCHIATRY 499
  3. 3. NEURAL SUBSTRATES OF RELIGIOUS EXPERIENCEmonic possession (Mark 9:14-29).’ Esquirol2#{176} in 1838 arousal with set cognitive schemata. Epileptic aurasand Morel2’ in 1860 recognized a heightened “religios- themselves are the most convincing evidence of theity” of epileptics, which they attributed to disability, insufficiency of attribution theory, instead demonstrat-social isolation, and greater need for religious consola- ing the existence of distinct physiologic neural sub-tion. The first reported conversion experience directly strates for several specific emotional states. Severalrelated to a seizure was noted by Howden, whose “psychic” auras, including depersonalization, dereali-patient experienced being transported to Heaven dur- zation, dreamy states, autoscopy, and ecstasy, are par-ing a fit. Spratlin3 in 1904 reported a religious aura in ticularly likely to engender religious interpretation and52 of 1,325 patients with epilepsy (4%). In the early 20th experience, and merit detailed review.century, Turner24 and others suggested that epileptics Among individuals with partial complex seizures, thedevelop a distinctive interictal character, among the frequency of auras ranges from 23% to 83%, and up tofeatures of which is religious fervor. A substantial num- one-quarter of auras are psychic in content.2729 The mostber of founders of major religions, prophets, and lead- common psychic or experiential ictal manifestations ofing religious figures have been documented as having temporal lobe epilepsy are fear, d#{233}j#{224} vu,jamais vu, mem-or suggested to have epilepsy (Table 1). ory recall, and visual and auditory hallucinations. Modern investigations of epilepsy-related religious Hughlings Jackson was among the first to identifyexperience have been marked by contradiction and con- and characterize less common ictal “intellectual auras”flict. This confusion in part reflects failure to distinguish (“dreamy states,” “cognitive auras”) in which the expe-among epilepsy-related religious experiences of ictal, rience of the immediacy and liveliness of one’s own orsubacute postictal, and chronic interictal occurrence. external reality is altered.31 The intellectual auras in-The phenomenology and neurobiology of each differ in clude depersonalization, derealization, and double con-important aspects. sciousness. Depersonalization auras produce an alteration or loss of the sense of one’s own reality, oftenIctal Events accompanied by a sense of detachment from others andIctal events of any type may be the subject of religious the environment, and of acting like an automaton. Dere-or cosmological explanation. Seizures are paroxysmal, alization auras generate an alteration or loss of the senseriveting, and unexpected-sudden intrusions of unan- of the reality of the external environment-for example,ticipated and often extraordinary experience into the the feeling that the external surround is just a dream-ordinary daily flow of consciousness. Patients who have and also are often associated with a sense of detach-culturally acquired explanatory systems of a religious ment. Double consciousness (“mental diplopia”) aurascharacter naturally tend to interpret any ictal experi- create a simultaneous experience of persisting remnantsence as possessing religious significance. Studies have of one’s normal consciousness and of a new quasi-demonstrated that experiences that are personal, im- parasitical consciousness with a different perception ofportant, negative, and medical, like most seizures, are reality. Auras of depersonalization, derealization, andparticularly likely to be interpreted in a religious frame- dreamy state account for approximately one-quarter ofwork.25 psychic auras.32 Some psychologists of religion have attempted to Well-documented localizations of spontaneous dis-explain religious experience by employing classical at- charges or electrical stimulations producing intellectualtribution theory. Experiments demonstrate that indi- auras are extremely rare. Available evidence, however,viduals not only interpret, but also inwardly experience, suggests that mesolimbic structures, the hippocampusthe same physiologic stimuli in strikingly different ways and especially the amygdala, are likely the critical gen-according to the cognitive expectations they carry. In erators of a feeling of unreality about the self or externallaboratory studies, identical, pharmacologically in- reality.33 The experience of unreality occurred in 9%duced sympathetic arousals are variably labeled and are of patients with temporal lobe epilepsy in one series,experienced across the spectrum of valence, from re- often accompanied by a sensation of fear.35 One patientwarding to distressful, according to the individual’s in Penfield’s series had a sense of “not being in thiscognitive set at onset.26 Attribution theory predicts that world” each time the first temporal gyrus was stimu-religious individuals with epilepsy will often experience lated, reflecting either direct lateral temporal corticalintrinsically neutral ictal physiologic events as having a excitation or rapid spread of afterdischarge to mesolim-religious-numinous character. This mechanism may in- bic structures. One patient in Gloor and colleagues’deed mediate some ictal religious experiences. more recent series37 repeatedly experienced a faraway Human experience, however, is clearly not simply the feeling during stimulation of temporal mesolimbicproduct of an interaction of nonspecific physiologic structures.500 VOLUME 9 #{149} NUMBER 3 #{149} SUMMER 1997
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