Book Review on the Subconscious Brain

Subconsciousness: Automatic Behavior and the Brain. Yves Agid. 2021. Columbia University Press. [ISBN 978-0-231-20127-8. 110 pages, including index. US$26.00 (softcover).]

Subconsciousness: Automatic Behavior and the Brain delves into the poorly understood connection between structure and function in the brain-particularly regarding intentional and unintentional behavior. Yves Agid discusses this obscure subject in a 100-page treatise that links the cerebral cortex with the basal ganglia and argues that intentional and unintentional behavior arise from the engagement and disengagement of neural pathways in between. The author clarifies early in his book that subconsciousness is not the Freudian concept of the unconscious mind—primarily repressed mental content that affects behavior. Subconsciousness is not easily discernible, in contrast to the clear sense of consciousness or meta- consciousness. He narrates a first-person account of a traffic jam in Paris—noting the intentional decisions (consciousness) and self-talk (meta-consciousness) during each event in traffic. Autopilot—driving without intentionally thinking about choices and actions—is the work of the subconscious. Later in the book, Agid asks the question that if the brain is operating on autopilot, is it possible to decide (like when driving) without being aware that a decision was made? (The answer is yes). Herein lies some of the complexity of the subconscious.

Text boxes are one method of highlighting important discoveries toward the link between structure and function in the brain. These pull-out boxes summarize case studies with significant outcomes. Box 4.3, for example, describes the famous psychiatrist Sigmund Freud’s rotation in a neurology department (pp. 82–83). This famous neurology research lab studied lesions in various parts of the brain. After death, an autopsy of the spinal cord and brain linked patient behavior while they were alive to the functionality of their brain postmortem. This early work led to the belief that links behavior to the health of various pathways in the different sections of the brain. It is important to note that although Agid strongly argues that the basal ganglia are primarily responsible for the brain’s subconscious functions, it is very much in collaboration with the cerebral cortex. “The basal ganglia are faithful collaborators of the cerebral cortex . . . They are not alone, isolated, and cut off from the rest of the brain, as they involve the cerebral cortex every time they are activated, just as they are activated every time the cerebral cortex drives deliberate behavior” (p. 72). It is a feedback loop of sorts. This description is, of course, a simplification of the extremely complex process occurring. “One might say that this is a caricatured reductionist perspective” (p. 72).

Agid devotes an entire chapter to a discussion about deficiencies in the structure of the brain and how those correlate to functionality. Two diseases that illustrate this well are Alzheimer’s and Parkinson’s. In Alzheimer’s disease the patient has problems related to memory, language, and perception, all controlled by the cerebral cortex while with Parkinson’s the patient cannot perform routine tasks like brushing teeth, walking, and writing—all controlled by the basal ganglia. “These two pathologies are somehow mirrored, which suggests, but does not demonstrate, that the cerebral cortex plays a predominant rule in nonautomatic behaviors, and conversely, that basal ganglia dominate in automatic behaviors (p. 57).

Perhaps because it is unavailable, information is not given to directly support brain scans and the Alzheimer’s/cerebral cortex link versus the Parkinson’s/ basal ganglia link. However, this lifelong researcher in the field of neurology and behavioral science seems convinced that link is probable.

Julie Kinyoun

Book Review: A New Metaphor for the Brain

 

An Internet in Your Head: A New Paradigm for How the Brain Works. Daniel Graham. 2021. Columbia University Press. [ISBN 978-0-231-19604-8. 344 pages, including index. US$30.00 (hardcover).]

“But metaphors—and especially technological metaphors—have been critical in the history of science, and they will continue to be so as we get closer to understanding the brain” (p. 27). Even before modern technology allowed us to use tracers and imaging techniques on the brain, philosophers and scientists used metaphors to encompass the intricacy and complexity of this critical organ. Seventeenth century philosopher René Descartes likened the brain to the plumbing behind the grand waterworks of the Palace of Versailles—water was pumped uphill from a nearby river—and artfully expelled several meters high on display—delivering more water than was supplied to all of Paris. Building upon this premise, Nobel Prize winner Charles Sherrington likened neurons to “valve-like” structures. Charles Darwin, famous for his work on evolutionary theory, was unable to conceptualize the brain, partly because he had no metaphor for it. He believed thoughts were secreted by the brain, like digestive chemicals. Gottfried Leibniz, co-inventor of calculus, suggested the brain was a type of mill—this suggests different processes operating at different levels. This morphed into the modern-accepted metaphor of the brain as a computer.

In An Internet in Your Head: A New Paradigm for How the Brain Works, computational neuroscientist Daniel Graham argues that although the computer metaphor for the brain is helpful and somewhat accurate, it is ultimately obsolete. Many current research observations and discoveries suggest an organ more akin to a network communicator, or an Internet. “There is no doubt that the computer metaphor has been helpful and that the brain does perform computations. But neuroscience based on the computer metaphor is incomplete because it does not consider the principles of network communication. Neuroscientists are starting to realize that, in addition to performing computations, the brain also must communicate within itself” (p. viii).

Graham cites experimental evidence for the flaws in the computer model: In a controlled study of monkey brains compared with a deep net artificial intelligence system, the deep net system predicts less than half of the neuron activity over time. Besides showing the inadequacy of a deep net, this experimental evidence suggests the system is missing the most important signals occurring in the monkey brains.

For the rest of An Internet in Your Head, Graham provides a comprehensive analysis of the ways in which the Internet does and does not correlate to what scientists currently understand about the functionality of the brain. Flexible routing, asynchronous communication, management of errors, background noise, overall growth of the network (and other phenomena) can all be explained in more depth by an Internet-like structure rather than by a computer. Graham argues that a structure of multiple hubs connected in multiple ways creates a net of communication on many different levels. A problem with his analysis is that some of the vocabulary and experimentation is very specific to the field and an understanding of both electronics and neuroscience seems required to follow all the arguments.

And ultimately, scientists don’t have the ability to experiment with the brain’s inner workings. “Many of the limitations are procedural: it boils down to the fact that living brains, particularly human brains, are difficult to study, whereas single neurons are tractable” (p. 67).

Julie Kinyoun