, London Jackson was an innovative thinker and a prolific and lucid, if sometimes repetitive, writer. Though his range of interests was wide, he is best remembered for his seminal contributions to the diagnosis and understanding of
epilepsy in all its forms and complexities. His name is attached eponymously to the characteristic "march" (The Jacksonian March) of symptoms in focal motor
seizures and to the so-called "dreamy state" of psychomotor seizures of
temporal lobe origin. His papers on the latter variety of
epilepsy have seldom been bettered in their descriptive clinical detail or in their analysis of the relationship of psychomotor epilepsy to various patterns of pathological
automatism and other mental and behavioural disorders. Jackson also did research on
aphasia, noting that some aphasic children were able to sing, even though they had lost the power of voluntary speech. He also studied what types of language loss was found in patients with left-brain injury, including set phrases, such as "Good bye" and "Oh, dear." In his youth Jackson had been interested in conceptual issues and it is believed that in 1859 he contemplated the idea of abandoning medicine for philosophy. Thus, an important part of his work concerned the evolutionary organization of the nervous system for which he proposed three levels: a lower, a middle, and a higher. At the lowest level, movements were to be represented in their least complex form; such centres lie in the medulla and spinal cord. The middle level consists of the so-called motor area of the cortex, and the highest motor levels are found in the prefrontal area. The higher centres inhibited the lower ones and hence lesions thereat caused 'negative' symptoms (due to an absence of function). 'Positive' symptoms were caused by the functional release of the lower centres. This process Jackson called 'dissolution', a term he borrowed from Herbert Spencer. The 'positive-negative' distinction he took from Sir John Reynolds. Continental psychiatrists and psychologists (e.g. Théodule Ribot, Pierre Janet, Sigmund Freud, Henri Ey) have been more influenced by Jackson's theoretical ideas than their British counterparts. During the 1980s, the 'positive-negative' distinction was introduced in relation to the symptoms of schizophrenia. He was one of only a few physicians to have delivered the
Goulstonian (1869),
Croonian (1884) and
Lumleian (1890) lectures to the
Royal College of Physicians. He also delivered the 1872 Hunterian Oration to the
Hunterian Society.
Methodology Jackson could not use modern sophisticated neuro-investigative technology (it had not been invented), but had to rely upon his own powers of clinical observation, deductive logic and autopsy data. Some of his eminent successors in the field of British neurology have been critical of many of his theories and concepts; but as Sir
Francis Walshe remarked of his work in 1943, " ... when all that is obsolete or irrelevant is discarded there remains a rich treasure of physiological insight we cannot afford to ignore." In
Otfrid Foerster's research on the motor cortex, he cites exclusively Hughlings Jackson for the initial discovery (although without evidence) of the brain as the spring of neurological motor signalling. == Contributions ==