The History of Neuropsychology

Prehistoric Era: Cranial Trephination
The purpose of cranial trephination, as practiced by prehistoric groups was largely to treat traumatic head injuries. Some trephinations were performed to treat headaches and seizure disorder. There were three main methods: Cutting, Scraping, Grooving and Drilling.






  This image on the left depicts the drilling method. Here, the practitioner has produced ring of small holes. The next step in the procedure was to cut the bone betwen each hole and pry off the bone piece in the center. This patient probably died before the trephination was completed. There is no evidence of healing. There is also a large linear skull fracture beside the trephination opening. It is clear that this trephination was used to treat the associated skull fracture. Perhaps the practitioner believed that a blood clot was underneath the skull, near the fracture. Such blood clots are a frequent result of this type of traumatic skull injury.

This skull on the right shows evidence of multiple head injuries and trephinations. There is a well-healed trephination and a fresh one. The patient probably died soon after receiving this recent head injury and fresh trephination. This one demostrates the great survival rate associateed with the procedure. This person lived for many years after the first trephination. There is considerable healing. This trephination was done with the scraping method.

Here is a fresh trephination done in series,using the straight cutting method. The practitioner began with cuts that surround the central area. He began cutting the outer perimeter in order to create a larger opening, but stopped, presumably because the patient died. This trephination shows no signs of healing. You can even see numerous fresh cuts and scrapes produced by the trephining tool.


Early Historical Era: The Egyptians
The Edwin Smith Papyrus (2500-3000 BC). This papyrus represents the earliest written record of medical treatment. Among the 48 cases described, are included references to head and brain injury. These descriptions suggest, for the first time, that brain functions are localized in specific parts of the brain. Here is an example: "If you examine a man having smashed his skull, under the skin of his head, while there is nothing at all upon it, you should touch and explore his wound. Should you find that there is a swelling protruding on the outside of that smash to his skull, while his eye is askew because of it, on the side of him having that injury which is in his skull; and he walks shuffling with his sole, on the side of him having the skull injury".

These are references to weakness on one side of the body (hemiplegia) and the build-up of pressure, probably a blood-clot in this case. The Egyptian physician was unclear about the side of the hemiplegia. Of course, hemiplegia occurs on the side opposite to the lesion. The Egyption physician may have been confused by the presence of a cotra-coup injury, in which a brain lesion occurs on the opposite side of the brain from the initial impact.

The Greeks
The Greek physicians who authored the writings attributed to Hippocrates observed the association between lesions on one side of the brain that produced seizures on the opposite side. Unfortunately, their knowledge of brain function was apparently limited by the strong aversion to dissection. They had a number of mistaken beliefs. The most prominent among these was the localization by Aristotle of mental functions in the heart. He used this to explain that people with heavy upper bodies were intellectualy dull because of the extra weight bearing on the heart. Although the Greeks maintain a number of these incorrect, dogmatic assertions, Aristotle also correctly observed a number of the features of cognition. In particular, he correctly dissociated immediate recall and perception from long-term memory. This distinction is demonstrated now in models of memory and its measurement.

Later Historical Era: The Cell Doctrine
This theory postulated that mental functions were localized in the ventricles (called Cells) of the brain. The theory was proposed by Nemesius and Saint Augustine in the fourth century. It was strongly influneced by the anatomical studies of Galen in the second century, in which he described the ventricles in detail and developed his own theory of "psychic gases and humours", that flowed through the body and ventricles, giving rise to mental functions. This theory persisted for 1000 years. Mental functions derived from the descriptions of Aristotle, such as memory, attention, fantasy and reason, were assigned locations within the ventricles. These images depict the connections between the senses (vision, hearing etc.) and the "Common Sense", located in the first ventricle. Cognitive function were then arrayed from front to back in the ventricles.

The Anatomy Studies of Vesalius (1514-1564)
Vesalius was the first to conduct careful observations of brain antomy and qualify the teachings of the cell doctrine in which he was trained. He represents the dawn of an era in which careful observations and empirical science began to triumph over dogmatic ideas that had been handed down since the time of Aristotle and Galen. Although much new information was gathered concerning the correct anatomy of the brain, the work of Vesalius did not have a direct bearing on knowledge of brain function.

Phrenology (Gall) vs Holistic Theories of Brain Function (Flourens)(1796-1850's) Depicted above is a Phrenology diagram for "The Perfect Head". The fundamental idea of Phrenology was that complex mental faculties, such as Cautiousness, Combativeness and Agreeableness, and simpler functions, such as Memory, Calculation Ability and Color Perception, were localized in discreet areas of the brain. Phrenology correlated the mental faculties described by philosophers such as Thomas Reid with the development of specific brain areas. The development of these brain areas, called cerebral organs, resulted in skull prominences. These bumps could be analyzed and a Phrenology practitioner could determine the subject's personality and intelligence from analysis of
the skull, called cranioscopy. Phrenology represents the beginning of the strong localizationist doctrine that is present today. The opposite concepts were presented by Flourens (1794-1867). He asserted that functions were not so discreetly localized; the brain areas worked in concert, producing a general, complex function. This controversy was not resolved until the studies of 19th Century neurologists, expecially Wernicke.








19th Century Neurology: Broca - Language Expression
Here is depicted Broca's most famous case, "Tan", a patient who suffered a stroke of the left hemisphere who could only utter the phrase "Tan". The patient could accurately comprehend language. Broca then used this case and a number of others to prove conclusively that the expression of language was localized to the left frontal lobe. If you look carefully at the brain, you can detect a soft, fluid-filled area in the frontal lobe. This represents the empty space, or infarction that is caused by the drop in blood supply to that brain area (stroke).

Wernicke - Language Comprehension and Disconnection Theory
Several years after Broca presented his cases of frontal lobe lesions, Wernicke presented cases in which patients had lesions of the posterior parts of the left hemisphere and had trouble comprehending language. This resulted in the idea that compnent processes of language were localized. On the basis of Wernicke's observations, the modern docrtrine of component process localization and disconnection syndromes was begun. This doctrine states that complex mental functions, such as language, represent the combined processing of a number of subcomponent processes represented in widely different areas of the brain. A mental faculty like "Combativeness" described by the Phrenologists was not discreetly localized in the brain. Such faculties, if they have validity at all, are the result of a number of primary cognitive operations.

Korsakoff - Memory Disorder
In 1887, Korsakoff observed a correlation between memory disorder and toxic metabolic states. These early cases also included patients who were heavy and chronic abusers of alcohol. Wernicke observed similar cases that also included acute confusion and other neurological abnormalities. It became clear that the cases seen by Korsakoff and Wernicke were essentially different examples of the same disorder. It was discovered that these patients suffered a nutritinal deficiency that resulted in lesions of structures in the middle part of the brain. These structures are involved in remembering new information. The pattern of lesions and symptoms is now referred to as Wernicke-Korsakoff syndrome. Its existence established that memory was mediated by structures in the temporal lobes of the brain.

The Modern Era: Functional Systems
A.R. Luria established the theory of function systems. This theory is the culmination of the localization and connectionist theories begun by Wernicke. Luria's model consists of three interacting functional systems:
1) The attention and arousal system, mediated by the brainstem;
2) The sensory and memory system, located in the posterior parts of the brain;
3) the motor control, planning and evaluation system, utilizing the basal ganglia, cerebellum, motor parts of the cerebral cortex and the prefrontal cortex.

Neuropsychological Syndromes
The assessment of brain illness rests on the measurement and comparison of symptoms as manifestations of lesions to different parts of the brain. For example, Broca's aphasia consists of poor language expression in oral and written form, good comprehension of language, good reading and poor naming ability.

Neuropsychological Tests
Concurrent with theoretical developments, neuropsychologists have developed numerous tests designed to assess constructs and symptoms of brain injury and illness.