American Journal of Law & Medicine

Imaging the mind, minding the image: an historical introduction to brain imaging and the law.(Brain Imaging and the Law)


Since ancient times, people have yearned to attribute human behaviors to a physical source within the head. Recently, neuroimaging technologies have given us the technical ability to look at the living brain, its structures, and some of its functions without the need for invasive procedures. However, the science has a long way to go before these technologies can allow us fully to appreciate the anatomical and physiologic underpinnings of human thoughts, states of mind, motives, will, or behaviors.

In this Article, we use an historical overview to introduce the various new technologies for imaging the brain. Today, the goal of medical science is the same as it has always been: to make medical technologies valid, useful, effective, and safe; and to guide appropriate uses while protecting the public from the misuse of them. Brain images are particularly vulnerable to misuse because they are so visually attractive. This visual power can easily result in misunderstanding about what the images show and what they mean. History shows, however, that legitimate science and unfettered showmanship have always proceeded on parallel tracks. Currently, there is great need for guidance on the appropriate uses of brain imaging within medicine, but also in fields outside of medicine, and particularly in the courtroom in aid of judges who must determine whether the images, and expert testimony about them, can be admitted into evidence. In Part II of this Article, we discuss the discovery and growth of these technologies. In Part III, we discuss some of the dilemmas that have been raised by the use of brain imaging in the courtroom, highlighting criminal cases in which the outcome was strongly swayed by jurors who misinterpreted the meaning of the images. We argue that brain images be admitted into evidence only for the purpose of linking a structural abnormality to a specific deficit, and that functional brain images not be admitted for the purpose of establishing responsibility for, motivation for, or propensity to commit a particular behavior, or to show an inability to control a particular behavior. For example, the current use of fMRI findings to establish the cause of certain behaviors, or responsibility, motivation, or propensity for them, is premature and ignores the complexity of brain function. Indeed, given the current state of medical and scientific knowledge about the brain, once admitted as evidence, the courtroom is an inadequate forum for determining the "truth" of such evidence. The importance to judges of obtaining careful scientific guidance on these technologies cannot be understated, and we argue that professional medical societies could provide invaluable assistance by issuing guidance for judges faced with the task of evaluating the evidentiary value of brain images and the testimony of the expert witnesses who will interpret them. In Part IV, we conclude that a body such as the Institute of Medicine could serve the courts and the public by conducting periodic reviews of current brain imaging research, convening scholarly committees to consider various uses and needs for the technology both within medicine and in related fields. We further suggest that the President's Council on Bioethics continue to serve an educational role as a multidisciplinary advisory body on these issues, and as a forum and resource to the public on the ethical issues raised by the use of these technologies.


   What is Mind? 
   It does not Matter. 
   What is Matter? 
   Never Mind! 

Since antiquity, scientists have searched for the source of our reason, emotions, and behavior. Hippocrates, a trained Pythagorean, chose the head as the place where reasoning resides because it resembled a globe--the ideal geometric shape. (1) Observing that patients with depressed skull fractures had convulsions, Hippocrates hypothesized that certain behavioral disorders were influenced from the head. Indeed, his observations that the convulsions occurred in the body side opposite to the side of the head injury led to the beginning of the principle of "cruciate conduction" (meaning that the right side of the body controls the left side, and vice-versa) in the nervous system. (2) People, however, have always viewed the issue of how the brain relates to the mind through their understanding of the science of their time. In Hippocrates' time, aqueducts were the predominant mode of transport for water. Thus, it is not surprising that cerebral spinal fluid and the ventricles of the brain became the focus of their studies. (3) This spawned the "cell theory," which held that the ventricles were the source of brain function. (4) (Interestingly, the first modern neuroimaging technology would outline the ventricles (ventriculography)).

With the Renaissance came a new understanding of human anatomy, including that of the brain. The exquisite drawings of Vesalius (1514-1564) in his book, De Humani Corporis Fabrica Libri Septum (De Fabrica), were responsible for raising additional interest in brain structure. (5) Rene Descartes (1596-1650) took these developments one step further when he described the human body and brain as a machine. (6) He placed the soul/mind in the only brain structure that is unitary and not doubled--the pineal gland. (7) He envisioned the cortex ("bark") as a shield that encapsulates the pineal and protects it. (8) His theory of the brain as a machine was based on the principles of hydraulics. (9) He posited a mind that works in synergy but is physically separate from the body: a non-material "ghost" in the machine. (10) He recognized, however, that his model was insufficient. He wrote: "even a complete understanding of the brain will not bring a complete understanding of behavior." (11) Still, the mind-body dichotomy persists in modern thought, as does interest in correlating brain structure with human behavior. Indeed, there is an old maxim in medical lore that still holds true: philosophers and neuroscientists do the same thing--philosophers look at their own brains while neuroscientists look at other people's brains.

Following Descartes, seventeenth- and eighteenth-century interest in the attributes of the face and head gave rise to the fields of physiognomy and phrenology. Physiognomy was popularized by the works of philosophers like Johan Kasper-Lavater (1714-1801), (12) (and later by the nineteenth century work of Cesare Lombroso (1835-1909) in his book, L'uomo Delinquente (The Criminal Man)). (13) Physiognomy, the study of the shape of the body, head and face, raised questions about the possible biological basis of many behaviors, including criminality. (14) It attributed features of the head and face to not only aberrant behavior, but also to intelligence. (15)

Phrenology was a major subsequent development that began with the work of Franz Joseph Gall (1758-1828) and Joahanne Casper Spurzheim (1776-1832). (16) Their work correlated brain functions and character traits with protuberances on the skull, and generated much popular interest. (17) Gall spent considerable time studying criminals, parricide, cruelty, and sadism. (18) He and other like-minded scientists attempted to confirm their hypotheses by studying sculptures and paintings of famous criminals. (19) Soon, the field of cranioscopy (literally, "looking at the skull"), like physiognomy, became a standard in criminology. The work of phrenologists informed the work of scientists such as Pierre Paul Broca (1824-1888). (20) Broca is credited with discovering the area of the brain responsible for language while studying a patient named Leborgne (known in medical literature as "Tan"), who died in April 17, 1861. (21) This and other discoveries led to the era of localization. Soon afterward, the German neurologist Carl Wernicke (1848-1904) first posited that there are "centers" in the brain, and this became known as localization theory. (22) Of course, scientists who believed in a more "holistic" model of brain function criticized the localization theorists. Major neurologists such as John Hughlings Jackson (1835-1911) criticized the "centers" theory as too simplistic. (23) Jackson proposed a hierarchical system subserving most behavior function. (24) However, the concept of localization underlies the use of brain imaging techniques to this day. (25) Also, as recently as the early twentieth century, major research was still being directed toward finding a biological source of criminality and a correlation between criminality and the physical appearance and shape of criminals' heads. This included a large study by the Harvard scientist Ernest Hooton, who published a book on the American criminal in 1939. (26)

In 1895, Wilhelm Konrad Roentgen (1845-1923) revolutionized all of medicine with his dramatic discovery of the X-ray. (27) The medical importance of his discovery was apparent almost immediately: it was now possible to see physical structures within the body without surgery. (28) Within months, Roentgen became a world phenomenon. (29) His discovery inflamed competition on this side of the Atlantic. In order not to be left behind, William Randolph Hearst cabled Thomas Edison on February 5, 1896: "Will you as an especial favor to the Journal undertake to make cathodograph of human brain kindly telegraph answer at our expense." (30) Edison agreed, becoming the first person to attempt imaging the brain. Promptly, in his own inimitable style, Edison cleared his calendar and dedicated his entire laboratory to picturing the brain. (31) However, he quit just nine days later on) February 14, 1896. (32) This may have been because he recognized the dangers of radiation. (33) Edison told the New York Daily Tribune that he doubted his attempts to image the brain would be successful: "[T]he bony structure of the cranium would offer insuperable obstacles." (34)

Meanwhile, the technology for illuminating structures in the body continued to explode, partly because of the technical ease of producing X-rays. In November 1896, Harvey Cushing (1869-1939) produced an X-ray of a bullet that had lodged in a patient's neck. (35) Later, Cushing also demonstrated calcification in the brain of a patient with Sturge-Weber disease; a fact probably not lost on President Eliot of Harvard who had Sturge-Weber Syndrome and who recruited Cushing from Hopkins to become a professor of surgery at Harvard. (36) The next 20 years were devoted to work on x-ray images of the brain, during which time the field was led by Arthur Schuller (1874-1957). (37) Walter Dandy (1886-1946), a neurosurgeon at Johns Hopkins, introduced air into the ventricles of the brain and invented ventriculography, after learning from his teacher William Halsted (1851-1922) that gas in the intestines can act as a "contrast" in abdominal X-rays. …

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