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Orienting Perspectives in Neuroscience

...living creatures, first and last, have selves...

-Oliver Sacks

Contemporary philosophers of science continue to explore fundamental questions about the nature of mind and body—whether we think of the mental and the physical as one and the same or whether we regard the mind as a non-physical phenomenon independent of the body. Over the last century' researchers in neurology and the fields of neuroscience have documented the close connections between the dynamics of brain function and patterns of sensation, emotion, thought, and behavior, challenging the notion of the disembodied mind that Descartes had proposed in his dualism. A series of clinical scholars, notably' Kurt Goldstein, A. R. Luria, Antonio Damasio, and Oliver Sacks, have provided compelling accounts of cases drawn from their research and practice, exploring the ways in which brain pathology' may bring about radical changes in personality and behavior, precipitating a range of problems in functioning (see, for example, Damasio, 1994; Goldstein, 1940, 1942; Luria, 1966, 1987; Sacks 1985, 1995, 2010, 2012). Most thinkers have come to embrace an ontological materialism, believing that we cannot conceive of the mind as a non-physical entity' distinct from the brain. Even so, divergent points of view have shaped debate in the philosophy' of neuroscience over the years, challenging clinicians to adopt a critical pluralism in their understandings of brain and mind as they carry' out everyday practice.

Following the turn toward reductive biological models of explanation at the end of the 20th century, preceded by' the “decade of the brain” in the 1990s, some thinkers predicted that psychological domains of understanding would recede in light of the growing power of neuroscience to account for the origins of problems in functioning and mechanisms of change and growth. Paul Churchland, Patricia Churchland, and Stephen Stich advanced positions in the philosophy of mind known as eliminative materialism, anticipating a time when psychological explanations of behavior would be replaced by' scientific understanding across the fields of particle physics, atomic and molecular theory', organic chemistry, evolutionary biology', and neurophysiology (P.M. Churchland, 1981, 1995; P. S. Churchland, 1986). They proposed that mental states are fully reducible to the physical states of the brain, arguing that what we think of as mind or psyche has neither autonomy nor any causal power of its own, believing that biology'would one day provide a unified explanation of human behavior (see P. S. Churchland, 2013). In a completed neuroscience, they predicted, we would come to see mental concepts as relics of an outdated psychology.

Other philosophers have challenged the reduction of mind and meaning to the neural, emphasizing the inherent gap between the observable dynamics of brain activity and the unobservable experience of subjectivity, consciousness, and the essence of the self. In his classic essay, “What is it like to be a bat?,” Thomas Nagel argued that while our appreciation of neurophysiology allows us to understand the mechanisms of the sonar system—bats do not see but navigate through their sense of hearing and electromagnetic waves—it will never help us know “what it is like for a bat to be a bat” (1974, p. 439). He pointed to the gap between physical and phenomenological domains of experience in subsequent critiques of reductive materialism, arguing that consciousness has a subjective character, a what it is like feature, that the physical sciences alone cannot explain (Nagel, 2000).

David Chalmers has brought a muscular challenge to the materialist paradigm over the last quarter century, proposing that there is no property' of the brain that can account for human subjectivity' (Chalmers 1995, 1996, 2010, 2012). He argues that the subjective aspects of mental phenomena—ineffable qualities called qualia—are beyond the reach of human understanding. The nature of our subjective experience is fundamentally' different from our understanding of the neurophysiology' of the brain. Our experience of color, sound, smell, and touch—the look and feel and sense of things, the textures of life— cannot be reduced to the language of neurophysiology'. My experience of the warm, rich red of the peonies I rediscovered every' summer in my grandmother’s garden cannot be explained by' our understanding of the dynamics of activation in region V4 of the visual cortex. “Living creatures, first and last, have selves,” Sacks reminds us in his accounts of brain and mind (1984, p. 177). Human reality' is constituted by subjectivity’. “What it is to be a person is shaped by' what it is like for that person to be,” Jonathan Lear writes. “The meanings, emotions, and desires alive in a person’s soul play a crucial role in determining who that person is” (1990, p. 4).

William James and John Dewey criticized psychologists for treating mental states as if they' were fixed, static properties of brain function. They' viewed mind as activity, emphasizing dynamic processes of interaction. James describes the ways in which “psychic” as well as “physical” factors influence the operation of neural structures and functions. Consider, for example, the following passage from the Principles of psychology: “I hope that the reader will take no umbrage at my so mixing the physical and the mental, and talking of reflex acts and hemispheres and reminiscences in the same breath, as if they' were homogeneous quantities and factors of one causal chain. I have done so deliberately; for although I admit that from the radically physical point of view it is easy to conceive of the chain of events amongst the cells and fibers as complete in

Orienting Perspectives in Neuroscience 35 itself, and that whilst so conceiving it one need make no mention of ideas, I yet suspect that point of view of being an unreal abstraction. Reflexes in centers may take place even where accompanying feelings or ideas guide them” (James, 1890/1945, p. 33).

James introduced the metaphor of the “stream of consciousness” to represent our ever changing experience of sensation, emotion, thought, imagery, and behavior. In doing so, as Richard Sennett notes, he challenged us to explore the ways in which the concrete particulars of place, relational life, and activity influence ongoing states of mind and body—“where you are, who is with you, what you or they are doing when you have a particular thought, feeling or sensation” (2018, p. 175).

Dewey expanded James’ conception of consciousness in Experience and nature, elaborating a language of dynamic processes, emphasizing the ways in which changing contexts influence “a series of heres and nows” (1925, p. 230). “To see the organism in nature, the nervous system in the organism, the brain in the nervous system, the cortex in the brain is the answer to the problems which haunt philosophy. And when thus seen they will be seen to be in, not as marbles are in a box but as events are in history', in a moving, growing, never finished process” (1929, p. 241). Although there would be no mind without the brain, James and Dewey' realized, we cannot reduce our understanding of all mental phenomena to brain states. The physical, the psychological, the social, and the environmental interact in complex ways. Neurobiological processes influence mental life and behavior, just as psychological and social processes influence physiological functions and bodily states.

The crucial question we must ask ourselves as practitioners, David Brendel emphasizes in his treatment of the mind-body' problem, “is whether ontological materialists are justified in formulating explanations of human behavior that employ concepts from disciplines other than the physical sciences, such as psychology” (2006, p. 85).

Although research across the fields of neuroscience promises to deepen our understanding of the dynamics of brain activity, Brendel acknowledges it will never help us appreciate what it is like for us to be ourselves from the first-person perspective of lived experience, nor will it necessarily inform the ways we engage particular methods of help and care over the course of our therapeutic practices. He welcomes the advances of neuroscience, embracing a scientific outlook, but he rejects reductive versions of materialism that would foreclose humanistic paradigms of understanding. Drawing on the work of the philosopher Terence Horgan (1993), Brendel proposes “nonreductive materialism” as an alternative position. In following a non-reductive materialism, we assume that the psychological is ontologically part of the material world, but that mental properties exert causal influence without being reducible to physical properties (see Baker, 2009, for expanded account of nonreductive materialism).

The nature of human experience and the practical concerns of clinical practice require a multitude of explanatory' concepts bridging scientific and humanistic domains of understanding. In accord with the principles of clinical pragmatism, as Brendel shows in his account, a non-reductive materialism allows us to draw on biological, psychological, and social perspectives in our efforts to understand the whole person as an individual, explain problems in living, and formulate different approaches to help and care in light of the givens of the clinical situation. The ideas and methods that we engage at any particular point are determined by the conditions, concerns, tasks, and outcomes of our practice rather than by fixed commitments to particular scientific or philosophical positions. In working from clinical pragmatism, we accept the proposal that while the efficacy of psychotherapy may lie largely in the ways the experience alters the structures and functions of the brain, we realize the need to move beyond the domains of neurobiology and consider a wider range of heuristics in our formulations of what it means to be human, what is the matter, and what carries the potential to help. In this sense, as Brendel explains, we think of psychotherapy as a pragmatic project rooted in ontological materialism and brain science (2006, p. 88).

As we consider the dynamics of change and growth in psychotherapy from the perspective of neuroscience, it is important to clarify the ways in which we are using the terms “brain” and “mind.” For the purposes of our discussion, in accord with the non-reductive materialism outlined here, I draw on working definitions proposed by Daniel Siegel that shape understanding in the field of interpersonal neurobiology. He uses the term “brain” to refer to the extended nervous system, describing it as the “embodied neural mechanism that shapes the flow of energy and information,” “intimately interwoven with the physiology' of the body as a whole.” (Siegel, 2020, p. 502). His conception of “mind” encompasses the domains of subjective experience; awareness; information processing; and a regulatory function that he describes as “an emergent, selforganizing, embodied, and relational process of the extended nervous system and relationships” (2020, p. 507). From this perspective we regard the activity of the brain as a fundamental part of mind. As he emphasizes, however, our conception of mind is “broader than the brain and bigger than the individual body. Mind is fully embodied and fully relational” (2020, p. 507). The orienting perspectives of interpersonal neurobiology, synthesizing concepts and empirical findings across a range of disciplines over the last two decades, guide the following accounts of neural development and the dynamics of brain function.

The Brain

The brain encompasses features of organization and function that have moved neuroscientists to call it “the most complicated material object in the known universe” (Edelman, 2004, p. 14). In spite of the rapid advances in the science of mind over the last three decades, our knowledge of neural processes remains surprisingly limited, and researchers continue to explore the organization, development, and functioning of the brain.1

We can trace our understanding of the basic structures and functions of the brain to the scientific and artistic gifts of Santiago Ramon y Cajal, the Spanish neuroanatomist. Toward the end of the 19th century he created techniques in microscopy that allowed him to document the structure and connections of the cells of the nervous system. He was one of the first researchers to study the cellular functioning of the brain, and scholars have come to think of him as the architect of modern neuroscience. He produced nearly 3,000 drawings over the course of his research—recognized as works of art in their own right, sometimes compared to the scientific illustrations of Leonardo da Vinci—that scholars regard both as observations and arguments about the dynamics of brain function (King & Himmel, 2017; for further accounts of his scientific and artistic contributions see Dubinsky, 2017; Swanson, 2017).

Cajal proposed that the brain is made up of discrete cells, known as neurons, rather than a continuous network of cell appendages, as most neuroanatomists at the time believed. Over the course of his work he introduced basic principles that have come to provide the conceptual foundations for our understanding of the brain and the nervous system. In his formulation of the Neural Doctrine, he proposed that the neuron is the basic structural and functional unit of the nervous system. He described the defining features of the neuron in his iconic drawings, detailing the dendritic spine that receives signals from other neurons, and the growth cone, the appendage that allows neurons to make synaptic connections with other neurons. In the Theory of Dynamic Polarization, he argued that information flows through nerve cells in one direction, moving from dendrites to cell bodies to axons.

In line with the thinking of Freud and James, Cajal elaborated conceptions of neuroplasticity, proposing that the brain continues to mature across the course of life. Drawing on the language of nature to describe the structures and functions of the brain, he compared the cerebral cortex “to a garden filled with innumerable trees, the pyramidal cells, which can multiply their branches thanks to intelligent cultivation, sending their roots deeper and producing more exquisite flowers and fruits every day” (Cajal, 1894, cited in Ferreira, Nogueira & DeFelipe, 2014, p. 1). He emphasized the ways in which experience changes the brain, and he recommended “cerebral gymnastics” for the ongoing development of mental functions, prefiguring our current practices of brain fitness (Ehrlich, 2017; see Ferreira, Nogueira & DeFelipe, 2014, for an account of the intellectual traditions and research that shaped Cajal’s conceptions of neuroplasticity).

 
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