Postlesion Recovery of Motor and Sensory Cortex in the Early Twentieth Century

This article addresses early work on partial recovery that followed small motor cortical lesions. Leyton and Sherrington (1917 Leyton, ASF and Sherrington, CS. 1917. Observations on the excitable cortex of the chimpanzee, orang-utan and gorilla. Q J Exp Physiol, 11: 135–222.  [Google Scholar]) studied the motor cortex in apes, hoping to learn more about the contralateral muscle representations. Then they placed small lesions within the precentral cortex, followed by a loss of the contralateral muscle twitches. The sudden loss remained for about one week, but recovery was observed and continued for weeks, up to a standstill. Sherrington and Graham Brown (1913) Graham Brown, T and Sherrington, CS. 1913. Note on the functions of the cortex cerebri. J Physiol (Lond), 46: xxii [Google Scholar] observed the same results in a serial, chronic experiment on a chimpanzee. The brain was sent to Monakow's Brain-Institute in Zurich for investigating the lesions and the degeneration pattern. Constantin von Monakow (1853–1930) had been a pioneer on recovery after acute lesions, coining the term “diaschisis.” During WWI, Graham Brown and Stewart (1916) Graham Brown, T and Stewart, RM. 1916. On disturbances of the localization and discrimination of sensations in cases of cerebral lesions, and on the possibility of recovery of these functions after a process of training. Brain, 39: 348–454. [Crossref] , [Google Scholar] studied a soldier in a British army hospital who suffered from a cerebral gunshot wound, localized in the sensorimotor cortex. Early and prolonged rehabilitation was successful. In 1950, Glees (1909–1999) and Cole (Oxford) placed a small motor-cortical lesion in macaque monkeys; for a few days, the monkeys had difficulties and were slow for the task. Daily training was resumed and recovery was accelerated by alimentary reward. Finally, Lashley (1890–1958) understood that handicapped patients “achieved their goal with variable means.” This demonstrated the value of active and prolonged rehabilitation, in addition to the (passive) recovery of function.     

Diffusion of Electrical Current in the Experiments of Fritsch and Hitzig and Ferrier Failed to Negate Their Conclusion of the Existence of Cerebral Motor Centers

This paper explores the implications of an early criticism of the stimulation studies of Fritsch and Hitzig and Ferrier for localized brain functions. Fritsch and Hitzig and Ferrier concluded that motor centers reside in the cortices of the hemispheres. Their studies were replicated, but their conclusions were not generally accepted initially. The most salient, laboratory-based criticism was that the electrical current used for stimulation diffused well beyond the cortex making their conclusion of cerebral motor centers unacceptable. The diffusion argument was essentially a French suggestion. Ferrier's and American research and interpretations provided data and arguments against it.     

An American Controversy about the Localization of Cutaneous Sensory Regions and their Relation to Motor Regions

Three American neurologists (C. K. Mills, C. L. Dana, and M. A. Starr) explored the anatomical limits of the motor and tactile systems in the brain from 1884 to 1895. Their papers and critiques of one another show contemporary knowledge, limits of their thinking, and difficulties deciding between alternatives. The issue for them was whether there were separate sensory and motor regions or whether there was a combined sensory-motor region. They based their localization arguments on clinical and laboratory findings and on the conclusions of H. Munk and D. Ferrier. There is a discussion about why differences were unresolved.     

Biological and Epistemological Models of Localization in the Nineteenth Century: From Gall to Charcot

In the latter half of the nineteenth century, the localizationist doctrines became closely associated with the memory trace paradigm. The analysis of the texts dealing with the localization and the nature of ‘the loss of articulated speech’ (motor aphasia) by Bouillaud, Lordat, Dax, Broca, Trousseau, Baillarger, Charcot and Wernicke shows how the biological paradigm of localization presented by Gall and based on the notion of organ-function correspondence was transformed into a model based on localizable memory traces. This change resulted in the theoretical unification of the mechanisms of motor and non-motor forms of aphasia. These forms, which the earlier authors tended to separate in their analyses of the underlying mechanisms, were now regarded as involving similar mechanisms related to the loss of mnestic images. The crucial step in this development was taken by Broca who presented the hypothesis that the faculty of coordination of speech movements, which according to his predecessors was the faculty lost in motor aphasia, was actually an intellectual faculty and a specific form of memory, and motor aphasia consequently a selective kind of amnesia. Theorists like Charcot and Wernicke generalized this idea into a comprehensive theory of the nature of localization based on the notion of memory traces. Thus, the localization of function was reduced to the localization of representations. Instead of biological paradigms, this model of localization is rooted in the epistemological tradition of psychology represented by Locke and Condillac, who were primarily interested in the problem of representation. In physiology, this approach usually resulted in attempts at localizing representations instead of functions.     

Neurognostics Answer

Although many individuals contributed to the development of the science of cerebral localization, its conceptual framework is the work of a single man—John Hughlings Jackson (1835–1911), a Victorian physician practicing in London. Hughlings Jackson's formulation of a neurological science consisted of an axiomatic basis, an experimental methodology, and a clinical neurophysiology. His axiom—that the brain is an exclusively sensorimotor machine—separated neurology from psychiatry and established a rigorous and sophisticated structure for the brain and mind. Hughlings Jackson's experimental method utilized the focal lesion as a probe of brain function and created an evolutionary structure of somatotopic representation to explain clinical neurophysiology. His scientific theory of cerebral localization can be described as a weighted ordinal representation. Hughlings Jackson's theory of weighted ordinal representation forms the scientific basis for modern neurology. Though this science is utilized daily by every neurologist and forms the basis of neuroscience, the consequences of Hughlings Jackson's ideas are still not generally appreciated. For example, they imply the intrinsic inconsistency of some modern fields of neuroscience and neurology. Thus, “cognitive imaging” and the “neurology of art”—two topics of modern interest—are fundamentally oxymoronic according to the science of cerebral localization. Neuroscientists, therefore, still have much to learn from John Hughlings Jackson.     

350th Anniversary of Les Passions de l'Ame

1999 marks the three hundred and fiftieth anniversary of the publication of Descartes' final work: Les Passions de l'Ame. This short paper commemorates that event and discusses the circumstances contributing to its origin and the questions which it still raises for neuropsychology three hundred and fifty years later.     

Cortical epileptogenesis and David Ferrier

There was an increasing medical interest in the localization of representation of function in the cerebral cortex after Broca in 1861 identified a cortical area that appeared responsible for expressive speech. By the late 1860s, John Hughlings Jackson—based on clinico-pathological correlations mainly in persons with focal motor seizures—had reasoned that contralateral somatic motor function was represented in another area of the cortex. This localization was supported by Fritsch and Hitzig (1870) in experimental cortical stimulation studies in dogs. These authors also reported producing events resembling contralateral motor convulsing in their animals. Their work, and Jackson’s ideas, prompted David Ferrier, in Great Britain, to begin a program of cerebral cortical stimulation studies in various vertebrate species, trying to locate cortical sites of representation of functions other than expressive speech and motor activity. In his initial report of his investigations (1873), he noted that appropriately sited Faradic stimulation evoked immediate or delayed contralateral focal motor seizures, some of which evolved into generalized convulsions. On this basis he reasoned that focal motor and generalized seizures were expressions of the same disorder; that nearly all epilepsies originated in the cerebral cortex and not in the lower brain stem, as hitherto thought; and that the clinical pattern of epileptic seizure phenomenology depended on the function of the cortical site of origin and the extent and direction of spread of seizure activity in the brain. He not only provided experimental verification for Jackson’s reasoning about epileptic seizure mechanisms but expressed the ideas a good deal more clearly than Jackson ever managed to do. Ferrier’s achievement in this regard has tended to escape notice, lost sight of because of the great importance of his investigations into localization of cerebral function.     

Cerebral Automatism,the Brain,and the Soul in Bram Stoker’s Dracula

Neither literary critics nor historians of science have acknowledged the extent to which Bram Stoker’s Dracula (1897) is indebted to late-Victorian neurologists, particularly David Ferrier, John Burdon-Sanderson, Thomas Huxley, and William Carpenter. Stoker came from a family of distinguished Irish physicians and obtained an M.A. in mathematics from Trinity College, Dublin. His personal library contained volumes on physiology, and his composition notes for Dracula include typewritten pages on somnambulism, trance states, and cranial injuries.

Stoker used his knowledge of neurology extensively in Dracula. The automatic behaviors practiced by Dracula and his vampiric minions, such as somnambulism and hypnotic trance states, reflect theories about reflex action postulated by Ferrier and other physiologists. These scientists traced such automatic behaviors to the brain stem and suggested that human behavior was “determined” through the reflex action of the body and brain—a position that threatened to undermine entrenched beliefs in free will and the immortal soul. I suggest that Stoker’s vampire protagonist dramatizes the pervasive late-nineteenth-century fear that human beings are soulless machines motivated solely by physiological factors.     

A historical review of investigations on laterality of emotions in the human brain

Different models of emotional lateralization, advanced since the first clinical observations raised this issue, will be reviewed following their historical progression. The clinical investigations that have suggested a general dominance of the right hemisphere for all kinds of emotions and the experimental studies that have proposed a different hemispheric specialization for positive vs. negative emotions (valence hypothesis) or for approach vs. withdrawal tendencies (motivational hypothesis) will be reviewed first and extensively. This historical review will be followed by a short discussion of recent anatomo-clinical and activation studies that have investigated (a) emotional and behavioral disorders of patients with asymmetrical forms of fronto-temporal degeneration and (b) laterality effects in specific brain structures (amygdala, ventro-medial prefrontal cortex, and anterior insula) playing a critical role in different components of emotions. Overall, these studies support the hypothesis of a right hemisphere dominance for all components of the emotional system.