FROM THE CLASSROOM
Toward
Understanding
Consciousness
BY ELAINE REYNOLDS | PHOTOGRAPHY BY CHUCK ZOVKO
Consciousness. The mind. People are fascinated by the topic, and that interest is reflected in the popular media as well as scientific journals. Science magazine calls the biological basis of consciousness one of the important things we don’t understand. A recent special issue of Time included a package of articles labeled The Brain: A User’s Guide with a lead story on “The Mystery of Consciousness.” Scientific American just launched a specialty magazine on the mind.
However, the study of consciousness (or the mind; I use the terms interchangeably here) has only recently been deemed an acceptable field of scientific inquiry. Once considered a legitimate subject only in the domains of philosophy and religion, it has gained stature in cognitive science and neuroscience. New fields, such as neurotheology, are springing up around the study of the mind, creating new connections between these scientific disciplines and other sciences, humanities, and social sciences. The study of consciousness and the brain promises to have a far-reaching impact in many fields of scholarly inquiry.
I chose consciousness as a basis for my introductory class in neuroscience this spring because of the recent attention to the topic and because of its interface with so many other disciplines. In fact, a key aim of the course is to help neuroscience students put their coursework into a larger context and to show students from other majors the impact of this science on their own field of study. Of course, since I am teaching the course from a scientific perspective, the primary goal is to provide a fundamental knowledge of neuroscience. We asked: What is consciousness? The attempt to define it is more than just an intellectual exercise, as illustrated by the fact that this definition can be an important part of a medical professional’s analysis when examining an unresponsive patient.
Philosophers have been thinking about the connection between the mind and the body for some time, with the main ideas falling into two principal groups. Dualists believe that the mind and brain are separate, that the mind is not reducible to biological processes. Materialists, on the other hand, believe the mind is a direct property of the brain. Most nonscientists (and the teachings of most religious faith traditions) favor a version of dualism; there are scientists and philosophers in both the dualist and materialist camps. In this course we emphasized the materialist philosophy known as biological naturalism, proposed by the contemporary American philosopher John Searle of the University of California, Berkeley. He postulates that mental states are reducible to brain states, meaning that higher-order functions associated with the mind can be understood through brain science. One of our main texts was The Astonishing Hypothesis: The Scientific Search for the Soul by Nobel Prize-winning biochemist Francis Crick, who is famed for discovering, with James Watson, the double-helix structure of DNA. Frick’s premise is that the mind is an emergent property of the brain, i.e., that it emerges from brain function,
and indeed can be studied using scientific methods.
The students discovered that while consciousness is hard to define, several of its properties are agreed upon by experts in various fields and laymen alike, including these: consciousness is selective; it is continuous, or ongoing; it is personal and subjective; it allows one to interact with the environment; and, for most people, it is overwhelmingly visual. Because consciousness for most people has a strong visual component, visual awareness is a good first problem
for students to probe on the road
to understanding consciousness.
Scientists understand more about vision than perhaps any other brain process. Visual features, or cues —including color, shape, depth, and motion—define how we see the world. Optical illusions fool our visual system by manipulating these cues, demonstrating that our perceptions are constructed by our brains. Art also manipulates visual cues to represent reality and ideas, and consciousness has a role in both creating and perceiving art. Guest lecturer Elizabeth Chapman, an artist and architect, classified some art as part of the “physical eye tradition,” which uses one aspect of consciousness to create a representation of the world that a viewer interprets through memory. Another form of art, which represents the “thinking eye tradition,” uses another aspect of consciousness to express ideas or manipulate perceptions of form, she explained. The students also looked at theories produced by the Gestalt school of psychology which define the important visual cues of an image and set forth some general ideas about how the brain processes them. An example is the idea that our visual perception tends to group objects that are close together or of similar color.
To understand the biological basis of visual awareness, students required a basic grasp of neurological processes: the major component of the nervous system is the neuron, or nerve cell; the brain’s 10 billion neurons communicate with each other via electrical signals, called action potentials, which pass from cell to cell by means of chemical neurotransmitters; communication is governed by the pattern of neuronal connections and the pattern and rate of neuronal firing. Many regions of the brain are involved in visual processing, including the eyes, thalamus (at the top of the brainstem), occipital lobe (at the back of the brain), and areas of the temporal and parietal lobes of the cerebral cortex (on the sides of the brain). Visual cues are processed separately in the brain, then brought back together to create a perception of the whole visual field. It works like this. The cells of the retina capture light and begin processing information about color, edges, and motion. The spatial organization of the information captured by the retina is precisely maintained as the information passes through neural circuits to the thalamus and then to primary visual cortex in the occipital lobe. There the information on color, edges, and motion, as well as depth-related information, is analyzed and then transferred to special modules in adjacent areas for additional processing of motion and object features. In these modules, the object being viewed is identified as, say, a face, rather than an animal or a wrench. Neurons in higher-level processing areas of the temporal and parietal lobes identify the cues in our visual fields and also generate aspects of our perceptions of the cues. How the brain puts the visual cues back together into one holistic version of the visual field is a topic of much focus and debate. Some neuroscientists believe that synchronized neuronal firings between the higher-level processing areas may be how the image is “bound together” again.
Other parts of the brain also influence our perception of visual information. For example, our attention can cause us to grasp more details of our environment in one area than in another. Our emotions also color our perception.
It is thought that visual awareness emerges from interconnections, tremendous in number, among the parts of our brain involved in visual processing and between these and other parts of the brain. And so, it is thought that consciousness—the mind—exists within the circuitry
of the brain, contained in a net or web of neural interconnections.
Theories of consciousness based on neuroscience are in an early state of development, with years of experimentation to come before they are validated or discredited. Other related fields of science contribute to our understanding of consciousness through additional approaches. Cognitive science, for example, has been developing hypotheses of the mind that can be tested through the analysis of behavior. Computer science is attempting to model the brain by creating complex circuits and comparing their output to brain function. This type of modeling will continue to contribute to our understanding of the complex interconnections that may underlie consciousness.
After examining science-based models of the mind—looking at consciousness through the lens of biological naturalism, that is —students considered other ideas as well. Contemporary philosophers such as Daniel Dennett of Tufts University, a leading materialist, and David Chalmers of the Australian National University, a leading dualist, present alternative interpretations of consciousness
(and indeed many of their arguments are difficult to debate given the current state of knowledge of the biological basis of the mind). The world’s religions also offer another view of consciousness, or the soul. Buddhism has undertaken a subjective study of the mind for centuries, and the Dalai Lama is exploring connections between Buddhist interpretations of the mind and neuroscience. As a result, researchers have found that they can apply scientific techniques to monitor and analyze Buddhist monks’ ability to alter their own states of consciousness. Theologians from a variety of other religious backgrounds are also engaging in discussion with scientists. It may be that the dialogue between science and religion, although it has certainly been contentious at times, will lead to productive collaborations that yield valuable new insights
into human consciousness.
Syllabus: NEUR 201
Introduction to Neuroscience
Course Description:
This course takes a problem-based introduction to the field of neuroscience. The basic problem that will be our focus for the semester is consciousness. We will first attempt to define what we mean by consciousness and look at historical perspectives on this concept.
Then, we will focus on a scientific, neuroscience approach to the problem to accumulate the knowledge necessary to begin to address this problem. We will look at a current theory of consciousness based on this scientific approach and then look at alternative hypotheses, including those that are brain-based and those that are not. Finally
we will look at some of the manifestations of consciousness, including
a discussion of how consciousness may have arisen.
 
Required reading includes:
Francis Crick, The Astonishing Hypothesis: The Scientific Search for
the Soul; Mark F. Bear, Barry W. Connors, and Michael A. Paradiso,
Neuroscience: Exploring the Brain.
In “From the Classroom,” faculty members give insight into their particular subject, providing a window on the intellectual
rigor that characterizes the environment of academic excellence at Lafayette. This issue features Elaine Reynolds, associate professor of biology, who teaches, among other courses, Introduction to Neuroscience.
| 
