Historical Origins of Neuropsychology 

Neuropsychology's task is to account for how the nervous system produces human behavior.

Modern neuropsychologists originate from all branches of neuroscience. More members of the Society of Neuroscience received training in Neuropsychology (inc. biopsychology and physiological psychology) than any other single field. Modern neuropsychology is relatively new as a distinct discipline. What are the historical origins of this enterprise?

Hippocrates (400 BC): Greek physician of antiquity who is traditionally regarded as the father of medicine. His name has long been associated with the so-called Hippocratic Oath--certainly not written by him--which in modified form is still often required to be taken by medical students on graduating. Hippocrates believed that the brain was organ of intellect, that it controlled the senses and movement. He also noted that lesions produced a contralateral effect.

Aristotle (350 BC): Greek philosopher, pupil of Plato at Athens and tutor to Alexander the Great, Aristotle studied the entire world of living things. He laid what can be identified as the foundations of comparative anatomy and embryology, and his views influenced scientific thinking for the next 2,000 years. Aristotle conjectured that mind and body were merely two aspects of the same entity, the mind being merely one of the body's functions. Localized the "soul" as residing in the heart.

Herophilus (300 BC): Alexandrian physician who was an early performer of public dissections on human cadavers during the single, brief period in Greek medical history when the ban on human dissection was lifted. He is often called the father of anatomy. Noted the difference between sensory and motor nerves but thought that the nerves were hollow tubes containing fluid and that air entered the lungs and heart and was carried through the body in the arteries. Argued that the brain, not the heart, was the organ of intellect; that the third ventricle responsible for cognition, and the fourth ventricle was the seat of the soul.

Galen of Pergamum (150 AD): Greek physician who founded experimental physiology and was one of the most distinguished physicians of antiquity. Galen's influence on medical theory and practice was dominant in Europe throughout the Middle Ages and during the Renaissance. Influenced medical thought for 1000 years. Galen recognized that the arteries contain blood and not merely air. He showed how the heart sets the blood in motion in an ebb and flow fashion, but he had no idea that the blood circulates. Dissection of the human body was at that time illegal (although his early years were spent as a surgeon at the gladiatorial arena, which gave him the opportunity to observe details of human anatomy), so that he was forced to base his knowledge upon the examination of animals, particularly apes. He concluded it was not the ventricles but the brain itself which was important. Attributed the frontal lobes with being the seat of the soul.

Andreas Vesalius (1550): Renaissance Flemish physician who revolutionized the study of biology and the practice of medicine by his careful description of the anatomy of the human body. His methods, which included the dissection of human cadavers, soon convinced him that Galenic anatomy had not been based on the dissection of the human body, which had been strictly forbidden by the Roman religion. Galenic anatomy, he maintained, was an application to the human form of conclusions drawn from the dissections of animals, mostly dogs, monkeys, or pigs.

Rene Descartes (1596-1650): Replaced the Platonic idea of a tripartite soul with that of a unitary mind (res cogitans) distinct from the body. Descartes considered the body and the soul to be ontologically separate but interacting entities, each with its own particular attributes. Believed the ventricles controlled body via hollow tubes (nerves). An early locationist gesture was Descarte's localizing the seat of mind/brain interaction in a particular neurological structure, the pineal gland (chosen because it was an anatomically unitary structure – unlike the rest of the brain -- like the mind itself).  Descartes proposed a mechanism [see figure] for automatic reactions to external events.  External motions affect the peripheral ends of the nerve fibrils, which in turn displace the central ends. As the central ends are displaced, the pattern of interfibrillar space is rearranged and the flow of animal spirits is thereby directed into the appropriate nerves.  It was Descartes' articulation of this mechanism for automatic, differentiated reaction that led to his generally being credited with the founding of reflex theory.

Thomas Willis (1664): British physician who attempted to explain the workings of the body from current knowledge of chemical interactions; he is known for his careful studies of the nervous system and of various diseases. His (1664) "Anatomy of the Brain, with a Description of the Nerves and Their Function"), the most complete and accurate account of the nervous system to that time, he rendered the first description of the hexagonal continuity of arteries (the circle of Willis) located at the base of the brain and ensuring that organ a maximum blood supply, and of the 11th cranial nerve, or spinal accessory nerve, responsible for motor stimulation of major neck muscles. Willis also was first to describe myasthenia gravis (1671), a chronic muscular fatigue marked by progressive paralysis.

Luigi Galvani (1750): Italian physician and physicist who investigated the nature and effects of what he conceived to be electricity in animal tissue. His discoveries led to the invention of the voltaic pile, a kind of battery that makes possible a constant source of current electricity. Found that electrical stimulation of nerve caused muscle to contract. Electrical nature of nerve action.

Franz Joseph Gall (1758-1828): Austrian anatomist and physiologist, a pioneer in ascribing cerebral functions to various areas of the brain (localization). He originated phrenology, the attempt to divine individual intellect and personality from an examination of skull shape.  Convinced that mental functions are localized in specific regions of the brain and that human behavior is dependent upon these functions, Gall assumed that the surface of the skull faithfully reflects the relative development of the various regions of the brain. His popular lectures in Vienna on "cranioscopy" (called phrenology by his followers) offended religious leaders, were condemned in 1802 by the Austrian government as contrary to religion, and were banned. Three years later he was forced to leave the country.  His concept of localized functions in the brain was proved correct when the French surgeon Paul Broca demonstrated the existence of a speech centre in the brain (1861). It was also shown, however, that, since skull thickness varies, the surface of the skull does not reflect the topography of the brain, invalidating the basic premise of phrenology. Gall was the first to identify the gray matter of the brain with active tissue (neurons) and the white matter with conducting tissue (ganglia).

Phrenology: Johann Kaspar Spurzheim (1776-1832) and George Combe (1788-1858). Phrenology enjoyed great popular appeal well into the 20th century but was wholly discredited by scientific research.

The five principles upon which phrenology was based were: (1) the brain is the organ of the mind; (2) human mental powers can be analyzed into a definite number of independent faculties; (3) these faculties are innate, and each has its seat in a definite region of the surface of the brain; (4) the size of each such region is the measure of the degree to which the faculty seated in it forms a constituent element in the character of the individual; (5) the correspondence between the outer surface of the skull and the contour of the brain-surface beneath is sufficiently close to enable the observer to recognize the relative sizes of these several organs by the examination of the outer surface of the head.

More About Phrenology

Johannes Peter Müller (1825): German physiologist and comparative anatomist, one of the great natural philosophers of the 19th century. His major work was Handbuch der Physiologie des Menschen für Vorlesungen, 2 vol. (1834-40; Elements of Physiology). His most important achievement, however, was the discovery that each of the sense organs responds to different kinds of stimuli in its own particular way or, as Müller wrote, with its own specific energy. The phenomena of the external world are perceived, therefore, only by the changes they produce in sensory systems. His findings had an impact even on the theory of knowledge. He was one of the first to advocate the use of experimental techniques in physiology.

Marie-Jean-Pierre Flourens (1825): French physiologist who was the first to demonstrate the general functions of the major portions of the vertebrate brain. Flourens conducted a series of experiments (1814-22) to determine physiological changes in pigeons after removal of certain portions of their brains. He found that removal of the cerebral hemispheres, at the front of the brain, destroys will, judgment, and all the senses of perception; that removal of the cerebellum, at the base of the brain, destroys the animal's muscular coordination and its sense of equilibrium; and that removal of the medulla oblongata, at the back of the brain, results in death. These experiments led him to conclude that the cerebral hemispheres are responsible for higher psychic and intellectual abilities, that the cerebellum regulates all movements, and that the medulla controls vital functions, especially respiration. Flourens was also the first to recognize the role of the semicircular canals of the inner ear in maintaining body equilibrium and coordination. Flourens is generally credited with being the father of experimental brain research. He measured both behavior and brain events. He contended, in opposition to the prior claims of phrenology, that behaviors were not localized in the cortex, and argued, as Carl Lashley later would, that behaviors were diffusely localized, and that lesions led to general losses (Lashley’s law of mass action). He additionally noted that if the lesions were not too severe, that recovery of function was possible, and that restitution of function was the result of compensation by the remaining intact brain (Lashley’s law of equipotentiality).

Camillio Golgi (1843-1926):  Italian neurohistologist and neuropathologist.  Developer of a staining method (image to right) which allowed individual nerve cells to be visualized.  Received Nobel Prize in 1906 (with Cajal) for his work on the structure of the nervous system.  Erroneously believed that neurons were not separated by synapses, but were interconnected by continuous neural material.

Hermann von Helmholtz (1821-1894): German physiologist and physicist, one of the greatest scientists of the 19th century, Helmholtz made fundamental contributions to physiology, optics, electrodynamics, mathematics, and meteorology, but he is best known for his statement of the law of the conservation of energy. Was a student of Johannes Muller.  Helmholtz found that the nerve impulse was perfectly measurable and had the remarkably slow speed of some 90 feet (27 meters) per second. (This measurement was obtained by Helmholtz's invention of the myograph). The slowness of the nerve impulse was a blow against vitalism, and further supported those who insisted that it must involve the rearrangement of "ponderable molecules", not the mysterious passage of a vital force.

Santiago Ramon Y Cajal (1852-1934):  Spanish neuroanatomist who refined Golgi's staining technique to produce some of the first detailed drawings of a variety of types of neurons.  Disagreed strongly with Golgi, asserting that neurons were separated by synaptic space.  Below right are facsimilies of drawings of cortical neurons made by Cajal.

Franz Nissl (1860-1919):  Born in Germany, he gravitated to medicine and as a student in Munich he wrote on pathology of cortical cells in which he used a stain he createdwhich opened up a new era in neurocytology and neuropathology. "Nissl Granules brought out by basicaniline stains perpetuate his name." But he also did outstanding work in psychiatry and demonstrated the correlation of nerves and mental disease by relating them to changes in glial cells, blood elements, blood vessels, and brain tissue in general. He worked with Alzheimer on general paresis. In the last 10 years of his life he did studies in which he established connections between the cortex and certain thalamic nuclei. He will be remembered as a great neuropathologist.

Paul Broca (1861): French surgeon who was closely associated with the development of modern physical anthropology in France and whose study of brain lesions contributed significantly to understanding the origins of aphasia, the loss or impairment of the ability to form or articulate words. He founded the anthropology laboratory at the École des Hautes Études, Paris (1858), and the Société d'Anthropologie de Paris (1859).   Much of Broca's research concerned the comparative study of the craniums of the races of mankind. He used original techniques and methods to study the form, structure, and topography of the brain and sections of prehistoric craniums. In 1861 he announced his discovery of the seats of articulate speech in the left frontal region of the brain, since known as the convolution of Broca. Thus, he also furnished the first anatomical proof of the localization of brain function.

• Investigated expressive language area in patient named Tan.
• Studied 8 patients overall.
• Found that the posterior 1/3 of the left inferior frontal gyrus functioned as the center for motor images of words
• This was the first time that a complex mental function (language) had been localized in a particular part of the cortex.

Korbinian Brodmann (1868-1918):  German physician and anatomist who made a detailed study of the human cortex using the then newly developed Nissl stain.   Brodmann described 47 areas based on cytoarchitectonic features such as cell type, density and lamination (numbered simply in the order which he studied them).  Brodmann's areas are still widely used today.

John Hughlings Jackson (1835-1911): British neurologist whose studies of epilepsy, speech defects, and nervous-system disorders arising from injury to the brain and spinal cord remain among the most useful and highly documented in the field.  Jackson was physician to the National Hospital for the Paralyzed and Epileptic, London (1862-1906), and the London Hospital (1859-94). In 1864 he confirmed the discovery of Broca that the speech center of right-handed persons is located in the left cerebral hemisphere, and vice versa, by finding that, in most cases, he was able to associate aphasia (a speech disorder) in right-handed persons with disease of the left cerebral hemisphere.  One of the first to state that abnormal mental states may result from structural brain damage, he discovered (1863) epileptic convulsions, now known as Jacksonian epilepsy, that progress through the body in a series of spasms, and he traced them (1875) to lesions of the motor region of the cerebral cortex, or outer layer of the brain. Jackson's epilepsy studies initiated the development of modern methods of clinical localization of brain lesions and the investigation of localized brain functions. His definition (1873) of epilepsy as "a sudden, excessive, and rapid discharge" of brain cells has been confirmed by electroencephalography, a method of recording electric currents generated in the brain.

Gustav Fritsch and Eduard Hitzig (1860): Published a paper called "On the Electrical Excitability of the Cerebrum", in which they reported that electrical stimulation of parts of the cortex elicited movements of the contralateral limbs. Overturned three of Flouren’s central ideas: that the cortex is unexcitable, that it plays no role in producing movement, and that function is not localized. Bartholow (1874) later replicated these electrical stimulation experiments on a human patient.

Carl Wernicke (1874): German neurologist who related nerve diseases to specific areas of the brain. He is best known for his descriptions of the aphasias, disorders interfering with the ability to communicate in speech or writing.  Wernicke studied medicine at the University of Breslau and did graduate work at Breslau, Berlin, and Vienna before entering practice in Berlin. In 1885 he joined the faculty at Breslau, where he remained until 1904.  In a small book published in 1874, Wernicke tried to relate the various aphasias to impaired psychic processes in different regions of the brain; the book included the first accurate description of a sensory aphasia located in the temporal lobe. Wernicke also demonstrated the dominance of one hemisphere in brain functions in these studies. His Lehrbuch der Gehirnkrankheiten (1881; "Textbook of Brain Disorders") is an attempt to comprehensively account for the cerebral localization of all neurologic disease.

• Discovered the receptive language area in the posterior 1/3 of the superior temporal cortex.
• This area was identified as the area for the sensory images of words.

Neuropsychology's False Start: As this cook’s tour hopefully illustrates, by the early 1900's a discipline similar to modern neuropsychology was actually flourishing--the behavior of lab animals with definable cortical lesions was being studied, and the behavioral consequences of human neurological patients was being described by now-famous pioneers of neuropsychology, the likes of Leipmann, Hughlings-Jackson, Dax, Wernicke, Broca and Holmes.  For example, Freidrich Goltz (1890) hypothesized that if, as Fritsch & Hitzig claimed, neocortex had definable functions, then removal of the neocortex ought to result in the loss of those functions. In an experiment that anticipated Lashley’s later work, Goltz conducted such experiments on dogs, discovering that decorticate animals were more active than intact dogs, possessed normal or nearly normal sleep-wake cycles, panted when warm and shivered when cold, had normal spinal reflexes, even complex ones, could respond to sensory stimulation, although with elevated thresholds. Meanwhile, Wernicke was formulating his theory that human brains possessed two language zones, connected by a large fiber bundle. He reasoned that if the two area were disconnected, even though the zones themselves were spared, that a particular speech deficit should occur (later in this century shown to be true by Norman Geschwind). Leipmann hypothesized and later demonstrated that certain apraxias (inability to make discrete movements in response to verbal commands) were the result of disconnections between sensory and motor areas. Leipmann further hypothesized that the left hemisphere played a special part in the production of complex movements, noting that left hemisphere lesions frequently produced bilateral apraxia, whereas right hemisphere lesions often had no effect on either limb. It is very interesting that these important 19th century discoveries were lost for over 50 years, until interest was rekindled by 20th century neuroscientists like Geschwind, Penfield, Hebb, Milner, Kimura and Luria.

Reasons for this loss of early progress include: 1) the original articles written in German, whereas English-speaking scientists came to dominate neuroscience after the turn of the century; 2) the intellectual aberration known as radical behaviorism (Watson) came to dominate and stifle the advance of psychological research in neuroscience; and 3) the original data were often over-interpreted by their discoverers, like Wernicke, and the criticisms leveled against such overzealous interpretations dampened enthusiasm for neuropsychology. 4) Physiological and comparative psychology was over-influenced by the negative results of Lashley (1930's), and stuck to pretty much boring brainstem (hypothalamic) stuff like temperature regulation, hunger and thirst.   As a consequence, American experimental psychologists veered in the direction of cognitive processes, and have only lately recovered their senses and returned to neural mechanisms.

Renewal: The renewal of interest in neuropsychology began in earnest following WW 2 (partly due to the new crop of brain-damaged war veterans, as well as the crop of frontal lobotomy patients which arose thanks to the misguided psychosurgical efforts of Portuguese neurosurgeon Egaz Moniz). The rich 19th century material was not rediscovered until the late '60s, by neurologists like Geschwind, Teuber and Kimura, who read German. The vast explosion of technology in neuroscience has also aided interest in human neuropsychology.  Allied with neurology, neuropsychology (clinical neuropsychology in particular) probably developed at least one bad habit from the medical model: an overemphasis on abnormal function. This focus on abnormal behavior and the brain defects which may account for it make it too easy to lose sight of the more interesting questions regarding NORMAL structure-function relationships. Fortunately, the advent of sophisticated in vivo neuroimaging techniques, like PET and fMRI, as well as the application of sophisticated experimental techniques to normal and brain-damaged populations alike, is rectifying this situation.

ca. 4000 B.C. Euphoriant effect of poppy plant reported in Sumerian records

Up one level

Copyright © 1997 [Mark E. McCourt]. All rights reserved.
Revised: September 22, 2001.