CTNS Science and Religion Course Program

Advanced Workshop

Toronto July 1999

Neuroscience Focus Group

Summary:

What might our understanding of spirituality gain from work in the contemporary cognitive and neurosciences? Is our spirituality dependent on or determined by the life of our minds and brains? This discussion group will examine the implications of recent findings in the sciences of brain and mind for spirituality and religious belief. We will examine ways in which the scientific findings might be helpful, and ways in which they might be insufficient for a full understanding of spirituality. We will explore the relationship between our neuroscientific understanding of human consciousness, language, personality, complex reasoning, memory, emotion, and perception, and our understanding of personhood, individual autonomy, freedom of choice, self-determination, moral responsibility, and the problem of constructing meaningful lives. Do research findings in modern neuroscience only support some form of reductive materialism? Is there a place for the soul and what would that mean? What can the neurosciences contribute to understanding these issues both in the life of the human individual and in the context of human relationships?

A Selection of Major Findings:

Overall Neuroarchitecture

The central nervous system is a huge mass of circuitry, operating at many levels, providing central control and mediation between sensory input and motor output. It operates at levels ranging from sensory-motor reflexes, and motor modulation of sensory input, to a flexibility of response mediated by prefrontal cortex and memory systems that can include remembering and anticipating decades-distant events. Our capacities make us vast anticipations machines, such that most of our relating to the world is done via extensive and interacting cortical maps. Sensory information is relayed through the spinal chord to the way-station of the thalamus, and to primary sensory cortices in the posterior half of the brain, and thence to secondary and tertiary areas, responsive to increasingly complex and abstract features, including cross-modal integrations. Information from the posterior, sensory half of the brain through more primitive midbrain structures, to tertiary motor areas in the frontal cortex, responsible for our most general plans and intentions, thence to secondary motor cortex for more specific plans and behavior sequences (e.g. speaking), and finally to primary motor cortex for output. This simple circuitry is modified by various kinds of feedback, multiple and parallel mappings of sensory surfaces, and interactions with emotional and motivational structures in subcortical areas. Note that ascending pathways are often excitatory, but many descending influences are selectively inhibitory, enabling sophisticated and differentiated patterns of response over long periods of time. The sensory system, and the brain in general (much of which includes responsivity to its own patterns), is built to respond to changes in patterns of stimulation, many of which produce arousal and distress as well as pleasure, but which are central to the evolution of our sentience. We learn to modify our acts only when events do not fit our anticipations.

Neurobehavioral Plasticity

Neural structures and functions are constantly being shaped by their history of interactions with the outside environment. Cells and their interconnections proliferate, migrate, differentiate, and are pruned directly by experience, affecting synaptic connections, dendritic growth, neurotransmitter synthesis, and even vascularization. Deprivations of certain stimuli can result in the loss of cells detecting them; enriched environments can increase neuron size, dendritic spread, and even enzyme production. Neurobehavioral plasticity extends across the lifespan, language area maturation depending on pre-puberty stimulation, delayed-response maturation on late adolescent pruning of principal sulcus synapses, and aging memories on dendritic growth in parahippocampal gyri. Day-to-day plasticity may be important to the multiple realizability of mental functions, as even somatosensory maps may change size, and cells may shift specialization, both in response to greater use, and spontaneously over time.

Modularity

The unity of mind has been overstated. Our brains operate more like a system of committees who processing is domain specific and largely nontransferable. Like any complex architecture, it may require autonomous subsystems which can be selectively damaged. Evidence from selective damage, functional dissociation, and various brain scans have identified many examples of such modularization, such as in vision, face perception, and language.

Vision.

Face Perception. Not only do separate areas of the brain mediate voluntary and spontaneous facial expressions, but neuroimaging and primate single-cell recording implicates a particular area of the superior temporal sulcus in the right hemisphere for face perception, including cells which respond only to frontal facial profiles. Damage to face perception can be dissociated from other agnosias, such as word recognition, and suggests that faces are represented configurationally rather than by part-decomposition.

Language. Now-classic split-brain research indicated that information sent to the right hemisphere of split-brain patients was normally not included in their linguistic accounts (or their declarative awareness) of their experience. It appears that primary auditory information is transduced and passed to the parietal-temporal-occipital association cortex (the angular gyrus), and then to Wernicke’s area, in the posterior portion of the superior temporal cortex. This is the auditory memory area for words, damage to which causes comprehension difficulties, but not repetition or grammatical production. From Wernicke’s area, information is sent (via the arcuate fasciculus) to Broca’s area, in the posterior portion of the left inferior frontal gyrus, which is responsible for grammatical comprehension and speech programming. Despite these left-hemisphere language specialization, it appears that right hemisphere damage impairs judgments of coherence, verisimilitude, and plausibility, and produces failures in comprehension of context, presupposition, connotation, figures of speech, tone, point, and event-sequencing.

The Libet Experiment

A wonderful example of how conscious mental processes emerge out of neural processes, this experiment showed that in cases where subjects spontaneously flex their hands, the consciousness of an intention to flex occurs 350 msecs after electrical activity in the cortical area subserving hand movements. Nevertheless, subjects could apparently veto the flexion in the 200 msecs between the intention and the actual motor response.

Interconnections between CNS and Immune System

Social Support, Immunological Function, and Psychological Boundaries

Social support appears to enhance immunological function in some cases. This raises a range of issues about the relationship between biological, psychological, and social boundaries between self and not-self, and between self and other. Such boundaries may be at the heart of our understanding of personhood and its relationship to human development, the emergence of individuality and autonomy, historical and cultural diversity, ethical and moral responsibility, and the spirituality embodied in our separation from and connection to other human beings.

Reward Systems

Research on "self-stimulation" of brains in animals of a generation ago showed certain limbic centers to produce powerful rewards. Septal areas, but also amygdala, anterior hypothalamus, and the medial forebrain bundle appear to activate a midbrain dopaminergic system. This system involves a number of midbrain nuclei, with pathways running through the medial forebrain bundle, which project to the lateral hypothalamus, nucleus accumbens, preoptic and other limbic and cortical areas. This important primary reward system is affected by a wide range of addictive drugs, including ones which do not produce physical dependence. Some drugs seem to more directly effect this system (opiates; stimulants by blocking reuptake), but even the more complex effects of alcohol and nicotine include increases of dopamine release in this system. Even schizophrenia is likely to involve variations in the sensitivity of this system.

Memory

Our memory systems are likely to operate at a number of different levels, and include interactions between different modules in the brain. Non-declarative memories, like sensitization, habituation, perceptual learning, and classical conditioning, can be studied in lower animals. Sensitization and habituation, found even in sea slugs, involve variations in presynaptic facilitation. Cerebellar mediation of classical conditioning has been found in rabbits. Visual memory has been mapped in monkeys, involving pathways from the occipital cortex, along the inferior surface of the temporal lobe, with projections to the hippocampus and amygdala, and thence to thalamic nuclei.

Human beings also have declarative memories, which can be brought to mind and articulated (e.g. the semantic memory for facts and knowledge, or the episodic memory of personally experienced events). Such memories are made possible by a temporal lobe memory system, rooted in the hippocampus, damage to which produces a severe anterograde amnesia, an inability to store new long-term memories elsewhere in the brain, despite leaving intelligence, working memory, already established long-term memory, and non-declarative skill learning intact. Patients suffering from such damage, such as Milner’s H.M., or Sacks’ Jimmie G, live in a ceaseless present, unable to accumulate new memories through time. Infantile amnesia may be produced, in part, by the slow maturation of the hippocampus. The mechanism appears to be a long-term potentiation in the hippocampus, an excitatory synaptic response which may last for weeks. Damage to amygdala and hippocampus prevents learning a delayed non-matching to sample task (where an animal must displace the novel, unfamiliar object to get a reward), but not a simple discrimination task (simply picking the member of a familiar pair which has consistently been paired with reward).

Specific memory deficits can be produced by damage to a number of particular arteas of the posterior cortex, resulting in amnesias for color, faces, object names, and object locations. Specific damage can also produce a wide range of inabilities to recognize perceived objects, including agnosias for sounds, limb placement, and objects at various scales.

Working memory, our ability to access and activate the stored memories relevant to an ongoing task, depends on the dorsolateral prefrontal cortex. This is dissociable from the hippocampally mediated long-term memory, which one can develop without working memory. Working memory is what makes delayed responses possible, where one needs to keep track of recent responses or events, and there are cells in the lateral prefrontal area which respond only during the cue-response delay interval. Working memory, harmed by damage to the lateral prefrontal areas, makes possible performance on Piagetian object-permanence tasks, delayed alteration tasks, dimension shifting in a sorting task, discriminating which of two objects was presented more recently, and picking an unselected but familiar object out of a pair (one needs to keep track of the previous selection). The mechanism seems to involve a kind of inhibition of connections to task-irrelevant information, to ignore distractions.

Emotion and Reason

Much of our emotional life, being mediated largely by subcortical structures of the limbic system, is shared with the rest of the mammalian kingdom. This includes a set of nuclei and pathways in the basal forebrain, including the amygdala, mediating fearful and aggressive responses, the septum, mediating rewarding, pleasurable emotions, and the hypothalamus, containing a number of well-defined nuclei and pathways which play roles in mediating rage, aggression, intense pleasure, and sexual response, as well as directing the autonomic nervous system. Human-level emotional response involves a wide range of neocortical response as well. e.g. the portion of the posterior right-hemisphere which mediates the match of emotional tone to language. Given the evolutionary value of memory for emotionally compelling events, it should come as no surprise that the hippocampus, a limbic structure nestled bilaterally beneath the temporal cortex, should play an essential role in declarative memory.

Nevertheless, it is the tie between the ventromedial prefrontal cortex and the limbic system (especially the amygdala), which suggests an important tie between emotion and reason. It is largely the hypertrophy of the prefrontal cortex which provides the characteristic flexibility of thought, especially in planning and coordinating complex behavior, and patients with damage here tend to be dominated by perceptual information, lacking the inhibitions necessary to accomplish their own plans, or to respond to social constraints. With lateral prefrontal cortex intact, patients (like Phineas Gage, or Damasio’s Elliot) with ventromedial damage can still exhibit high intelligence and normal working memory. But in the real world of complex behavior, such patients lack the link between the prefrontal cortex and the limbic system which can narrow options automatically via the "somatic marking" of their potential affective consequences. They lose the ability to keep to a schedule, organize higher-order hierarchies of action, or even feel a sense of personal involvement. Such patients do not exhibit a normal GSR to emotional stimuli, nor is their risk-taking tempered by emotional response to the possibility of severe penalties. Lacking the affective ties for evaluating consequences, they have lost the ability to prioritize so necessary for complex reasoning, especially important for tasks with temporal constraints.

Bibliography

Austin, James H. Zen and the Brain. Cambridge, MA: MIT Press, 1998.

There is little in the contemporary neurosciences that this massive tome does not touch on, with a 150 page section on "Neurologizing," which ranges from a brain overview, discussions of basic drives, and memory systems, to the mechanisms of attention and awareness. It is also a deep account of Zen meditation, and an exploration of a range of states of consciousness, including experiences from phantom limbs to psychedelic drugs, including lengthy discussions of absorption, awakening, and ongoing enlightenment. Written over a decade by a neurology professor who is also a Zen adept, this is a powerful work, but probably more useful to advanced students. Not for the faint-hearted.

Brown, Warren S.; Murphy, Nancey; & Maloney, H. Newton (Eds.). Whatever Happened to the Soul? Minneapolis, Fortress Press, 1998.

Simply the best, most accessible, and most coherent collection around for dealing with the relation between biology and cognitive science and Christian theological anthropology. The authors take a consistent position, called "non-reductive physicalism" (NRP), which the book goes a long way to establishing as consistent with both scientific work about minds and brains and with biblical, theological, and moral concerns. Including chapters on historical background, evolution and genetics, and useful biblical scholarship on human nature. The chapter on "Brain, Mind, and Behavior" by Jeeves is a gem, especially his account of dualism and materialism, the discussion of the relation of neuroscience to spirituality, and of compatibilist accounts of free will. Brown catalogs the cognitive contributions to an emergent notion of soul based on personal relatedness, a neglected dimension of much contemporary work in cognitive neuroscience. The centerpiece is Murphy’s sophisticated account of NRP, including one of the clearest expositions of supervenience I have ever run across, and includes an extremely valuable NRP account of religious experience. For syntheses of the relation between brain, mind, and spirit, this book is a vital nexus.

Damasio, Antonio R. Descartes’ Error. NY: Putnam, 1994.

An engaging and fascinating read, and a very accessible book, drawing on reflections on forms of brain damage which profoundly alter personality without affecting intelligence, language, or many other higher cognitive capacities. The book also lays out a theory of the ties between emotion, reasoning, and the highest reaches of our capacities to organize meaningful lives. A work that is important, readable, and highly relevant to discussions of the relationship between our neural selves and our spiritual lives.

Edelman, Gerald M. Bright Air, Brilliant Fire. SF: HarperCollins, 1992.

An more accessible version of the author’s three-volume theory of neural Darwinism, the theory that brains develop, and minds emerge from the shaping of the neural jungle by experiential selection. Includes serious accounts of the biological basis of mind, including its morphology and topobiology, recognition, memory, and consciousness. Higher-order consciousness, including the individual soul and selves requiring reintegration are also addressed. Some of even this work gets a little technical, but it is not a vast tome, and the ideas developed are quickly applied to some of the issues relevant to the religion/science dialogue, including some warnings about the seduction of a number of untenable views about consciousness. It goes a long way toward dispelling the belief that mind could ever be understood without biology. This is an "exuberant materialism," but not a computational one, and provides accounts of things like "flow," self-expression, and the sense of life as a risky and uncertain journey. A global theory of mind and consciousness, and a biological theory of individuality and autonomy.

Flanagan, Owen. Consciousness Reconsidered. Cambridge, MA: MIT Press. 1992.

Probably the most succinct and balanced of a number of functionalist works on consciousness, the position, roughly, that the mind is to body as program is to computer (or that states of consciousness might be better thought of as logical rather than material states of the brain). Flanagan’s view is that while consciousness might be a kind of "virtual machine" or "user’s illusion," a story that we tell ourselves, that it nevertheless has real causal force. Chapters include discussions of the relationship of subjectivity to the natural order (1), identity theory (3), phenomenal consciousness (8), personal identity (9), and self-consciousness (10). Among the more useful aspects of the book are a naturalist explanation of why subjective consciousness cannot be captured from an objective point of view, and Flanagan’s careful distinction between our narrative, self-represented identity and our full actual identity, including all the possibilities of privacy, self-deception, and fictionality.

Gazzaniga, Michael. Nature’s Mind. NY: HarperCollins. 1992.

Gazzaniga is one of the original split-brain researchers, but has written a whole series of very accessible books on a wide variety of brain functions, and their relationship to emotional and mental life, including The Social Brain and Mind Matters. He has also co-authored several texts including Cognitive Neuroscience. Nature’s Mind uses a kind of neural Darwinism "selection theory" as a framework for addressing a wide variety of issues including immunology, brain plasticity and development, language, the specialization of intelligence, addiction and compulsion, aging, and even conscious experience. Good supplementary reading for a course on brain and spirit, or good central reading for the neuroscience component of a broader religion and science course.

Gregory, Richard L. (Ed.) The Oxford Companion to Mind. Oxford: Oxford U. Press, 1987.

Now over a decade old, still a marvelous reference work, with over a thousand entries, often by major figures, e.g. Chomsky on language, Luria on neurolinguistics. Includes a tutorial article on the nervous system, biographies of important thinkers, and entries ranging from autism, and consciousness, to Indian theories of mind, ESP, and visual processing. Marvelously cross-referenced and well-illustrated.

Pinker, Steven. How the Mind Works. NY: W.W. Norton, 1997.

This is an incredibly entertaining, and remarkably thoroughgoing account of what we know about the mind, ranging widely from the cognitive and neurosciences, to linguistics, artificial intelligence, and evolutionary biology. Laying out an evolutionarily rooted view of the mind as a collection of software modules, this is popular science at its best. Witty, cultured, and masterful, this is a tour-de-force accessible to undergraduates, turning difficult ideas into common sense, often with a great deal of humor. Reading this book felt like taking a course with a great teacher!

Sacks, Oliver. "Neurology and the Soul." The New York Review of Books, 22 November 1990.

Still one of the better essays out there, discussing Sacks’ work, as well as that of Penfield, Sherrington, Edelman, and Rosenfield. Presents a non-reductive but naturalistic view of the relationship between whole persons and brain function from the viewpoint of a healer. Addresses the uniqueness and personalized character of a wide range of brain damage and dysfunction, and the need of the neurosciences for the concept of the individual, and the relationship of our development to our brains and bodies. Sacks’ flavor is best captured by quoting him:

Schacter, Daniel L. Searching for Memory. NY: Basic Books, 1996.

A literate, artistically aware, scientifically informed account of memory and its vagaries by one of the major researchers of the day. Not light reading, but a fascinating, lucid account of the workings of memory, autobiography, and the distortions, amnesias, hidden influences, and false memories. Argues against the assumption that our minds are unitary wholes, and dismantles a whole range of memory myths, including that of remembering as objective replication. A great summary, and a readable narrative, the references to literature, the visual arts, and current affairs make it a rich teaching resource, and an engaging journey.

Solso, Robert C. (Ed.) Mind and Brain Sciences in the 21^st Century. MIT Press, 1997.

If you want an informed set of writings that will stimulate the imagination, this is a great collection. While frequently speculative, the authors in this volume are some of the best in the field, and the individual chapters are neither long nor daunting. Includes Sagan and Druyan on consciousness, Tulving on the future of memory research, and article on what to do with a personal brain scanner, and a wonderful piece by Gazzaniga on "What Are Brains For?"

Sperry, Roger W. "Psychology’s Mentalist Paradigm and the Religion/Science Tension." American Psychologist, 1988, 43:8, 607-613.

Important article in the flagship journal of psychology, by the late Roger Sperry, probably the premier brain-scientist of this era, the original split-brain researcher, and a long-time member of the editorial board of Zygon: Journal or Religion and Science. Essentially tries to redefine religious belief in terms of the cognitivist paradigm in psychology, using an understanding of mind as emergent, pressing for a biospheric ethic, and a teleology of evolutionary cognitive emergence. Sees religion as merging with humanism, relinquishing dualism and supernaturalism, making humanity its common good, and evolutionary progress an ultimate concern. Another version appears as "Search for Beliefs to Live by Consistent with Science," Zygon: Journal or Religion and Science, 26:2 (June 1991), 237-258.

Varela, Francisco; Thompson, Evan, & Rosch, Eleanor. The Embodied Mind. Cambridge, MA: MIT Press, 1991.

Focuses on the application of cognitive science to everyday experience, developing a dialogue with Buddhist meditative psychology, but also relating to traditions like phenomenology and psychoanalysis. A good account of cognitivism, and especially emergence and the relation between mind and self, and how consciousness is possible without a self.

Scientific American Mysteries of the Mind, Special Issue Volume 7:1, 1997.

A fantastic, thought-provoking issue of Sci Am, including articles on consciousness, mind-body interaction in disease, the neurobiology of emotion, depression and creativity, autism, and even the pursuit of happiness. Cutting-edge but accessible college-level material on a wide range of research in neurosciences, and its application to the "persistent mystery of ourselves."

"AI: A Debate." Scientific American, 1990 (January), 26:1.

Two articles in this issue put Searle’s anti-computational account up against the eliminativist marterialism of the Churchlands.