in this section make it clear that there is no shortage of neurological causes
that account for virtually all details that occur in tours of heaven. It is
important to note, however, that visits to the realm of gods and spirits cannot
be understood simply as random collections of some of the above-mentioned
motifs. How do such experiences yield the structured tours that are attested in
so many different parts of the world? In particular, how can we explain the
narrative plot of the tours of heaven?
7.7 TOWARD A NEUROSCIENTIFIC MODEL OF THE
NARRATIVE STRUCTURE OF THE TOURSIn this section, I will present two neuroscientific models of religious experience
that potentially shed light on the structure of tours of heaven, especially as they
are found in ancient Jewish and Christian sources.
McNamara (2009, pp. 127–30) identified a network of brain structures that
underlie religious experience. This network involves especially parts of the
limbic, temporal, and frontal cortices on the right. As we have seen in section
3.2 above, the limbic system consists of several structures at the center of the
brain and has been traditionally considered to play an important role in
emotions (Gazzaniga et al., 2014, pp. 428–9); the temporal lobes are located
on both sides of the brain behind the temples; and the frontal cortex is found
toward the forehead. According to McNamara (2009, pp. 131–43), the pro-
gressive pattern of religious experience emerges as a result of changes in
the balance of neurotransmitters in the brain. Neurotransmitters are sub-
stances carrying information between neurons as well as modifying their
functioning (see section 3.2). Neurons can detect neurotransmitters and let
them influence their behavior with the help of specializedreceptors, which
are located on the cell membrane and can be thought of as“docking stations,”
into which only selected types neurotransmitters fit. So-calledentheogens
(chemicals that are known to facilitate religious experience, such as LSD and
psilocybin) especially change the balance of two neurotransmitters in the
brain:serotoninanddopamine. Serotonin is produced in the raphe nuclei,
located in the brain stem at the base of the brain (where the brain is connected
to the spinal cord) and influences cognition, mood, and social behavior
(Young & Leyton, 2002; Puig & Gulledge, 2011). In the context of religious
experience, McNamara (2009, pp. 127–8) particularly emphasized the role of
serotonin in the functioning of the prefrontal cortex. The prefrontal cortex is
located behind the eyebrows and plays a central role in many higher-
order cognitive functions, including learning, memory, categorization,
inhibitory control, and cognitiveflexibility (Gazzaniga et al., 2014, pp. 508–20;
160 Cognitive Science and the New Testament