Frédéric Bremer
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Frédéric Bremer (28 June 1892 – 7 April 1982) was a pioneer in the field of
neurophysiology Neurophysiology is a branch of physiology and neuroscience concerned with the functions of the nervous system and their mechanisms. The term ''neurophysiology'' originates from the Greek word ''νεῦρον'' ("nerve") and ''physiology'' (whic ...
, whose work specialized in the neural mechanisms involved in the
sleep-wake cycle A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrai ...
. His other works include research into
aphasia Aphasia, also known as dysphasia, is an impairment in a person's ability to comprehend or formulate language because of dysfunction in specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine, but aph ...
and
apraxia Apraxia is a motor disorder caused by damage to the brain (specifically the posterior parietal cortex or corpus callosum), which causes difficulty with motor planning to perform tasks or movements. The nature of the damage determines the di ...
, the neurogenic origin of
diabetes insipidus Diabetes insipidus (DI) is a condition characterized by large amounts of dilute urine and increased thirst. The amount of urine produced can be nearly 20 liters per day. Reduction of fluid has little effect on the concentration of the urine. ...
, the physiology of the
cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...
, and the neural control of muscular tone.


Early life

Frédéric Bremer was born in
Arlon Arlon (; ; ; ) is a City status in Belgium, city and Municipalities in Belgium, municipality of Wallonia, and the capital of the Luxembourg (Belgium), province of Luxembourg in the Ardennes, Belgium. With a population of just over 28,000, it ...
, in the Belgian
Ardennes The Ardennes ( ; ; ; ; ), also known as the Ardennes Forest or Forest of Ardennes, is a region of extensive forests, rough terrain, rolling hills and ridges primarily in Belgium and Luxembourg, extending into Germany and France. Geological ...
in 1892. His parents were both well educated: his father and mother were teachers at the Arlon Public Secondary School. Frédéric Bremer himself was a bright student, who excelled in his medical studies at the University of Brussels. However, these studies were interrupted by the First World War, during which he served as military physician in a cavalry regiment, then later as a medical auxiliary at the famous Ocean Ambulance. This was a military hospital situated on the Belgian coast, in the city of
La Panne De Panne (; ) is a town and a municipality located on the North Sea coast of the Belgian province of West Flanders. There it borders France, making it the westernmost town in Belgium. It is one of the most popular resort town destinations within ...
, and was frequently attended by Queen Elisabeth of Belgium who worked there as a volunteer.


Education

In 1919, he started his training in
neurology Neurology (from , "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine) , medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous syst ...
, as the assistant of Professor
Pierre Marie Pierre Marie (9 September 1853 – 13 April 1940) was a French neurologist and political journalist close to the SFIO. Medical career After finishing medical school, he served as an interne (1878), working as an assistant to neurologist Jean- ...
at the Hôpital de la Salpêtrière in Paris. Then, as a Fellow of the
Belgian American Educational Foundation The Belgian American Educational Foundation (BAEF) is an educational charity. It supports the exchange of university students, scientists and scholars between the United States and Belgium. The foundation fosters the higher education of deserving ...
, he travelled to the US, and spent a year at
Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...
with H. Cushing, followed by visits to the physiology laboratories of
Walter Bradford Cannon Walter Bradford Cannon (October 19, 1871 – October 1, 1945) was an American physiologist, professor and chairman of the Department of Physiology at Harvard Medical School. He coined the term " fight or flight response", and developed the theory ...
and Alex Forbes. Before finally returning to Belgium, he also spent some time in the famous laboratory of Sir
Charles Scott Sherrington Sir Charles Scott Sherrington (27 November 1857 – 4 March 1952) was a British neurophysiology, neurophysiologist. His experimental research established many aspects of contemporary neuroscience, including the concept of the spinal reflex as a ...
in Oxford. In 1924 Bremer became an Aggregate (Fellow) of the University of Brussels and in 1932 started teaching "General Pathology" at the Faculty of Medicine. Bremer, who was a popular teacher, became Professor in 1934.


First publication

His first publications in 1920 and 1921 were clinical descriptions of aphasia and apraxia. His first scientific research paper, which was published in collaboration with P. Bailey from Cushing's laboratory, dealt with the neurogenic origin of diabetes insipidus. Bremer, together with Bailey, showed that a minimal lesion of the
hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...
can induce experimental diabetes insipidus. These lesions were also shown to induce sleepiness and
adiposity Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and ...
. In addition, their data suggested the existence of a "thirst" centre in the hypothalamus. When Bremer returned to Belgium and embarked on a research career of his own, he turned his attention to the investigation of the physiology of the cerebellum, and the neural control of muscular tone. These studies eventually led him to sleep research.


Sleep research

After some additional research in muscle tonus and the cerebellum, Bremer's curiosity pushed him towards the, what Bremer named, cerveau and encéphale isolé. Having observed the side effect of sleepiness after a lesion was produced on the hypothalamus, Bremer was curious as to what the effects of a lesion farther down would do. He decided to test his hypothesis by adapting a technique of decerebration in cats, that left the forebrain ''
in situ is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...
'' after a mesencephalic transection, and applying it to the intercollicular section. While the transection was not a directly planned investigation of sleep, but the results influenced his future research career very heavily. Bremer started his brain transection experiments at an opportune time. Neurophysiological techniques had greatly improved during the early 1930s with the introduction of Alex Forbes' electronic amplification. Electromagnetic oscillographs had replaced the Lippman electrometer and the
string galvanometer A string galvanometer is a sensitive fast-responding measuring instrument that uses a single fine filament of wire suspended in a strong magnetic field to measure small currents. In use, a strong light source is used to illuminate the fine filamen ...
in electrophysiological experiments. These newly introduced techniques allowed Lord Adrian and Matthews to confirm Hans Bergers revolutionary discovery of alpha electroencephalographic activity in humans. With these advances in technology Bremer was able to start his transection experiments on cats, and accurately record the resulting brain function. His first procedure was to make a transection in the midbrain, the results were dramatic. The transection had deprived the brain of the ascending sensory impulses, except the olfaction and optical, and in so doing had caused a state identical to barbiturate sleep. This state was persistent as well as indefinite. This result lead Bremer to formulate the hypotheses that the immediate cause of sleep was a complete deprivation of sensory input from the impulses of the spine. In order to further evaluate his deafferation "sleep hypothesis", Bremer conducted a second experiment in which he made a transection at a much lower level- just above where the brain stem and spinal cord meet. He termed this procedure the encéphale isolé, with this procedure he deprived the brain of all sensory input from the spine, but left all input from the cranial nerve intact. These results were very different from the midbrain transection. In contrast to the perpetual sleep state, the lower transection simply caused and alteration of sleep and wake cycle that was not different from a regular cat. This strengthened his belief in his hypothesis. Although unaware of the
reticular activating system The reticular formation is a set of interconnected nuclei in the brainstem that spans from the lower end of the medulla oblongata to the upper end of the midbrain. The neurons of the reticular formation make up a complex set of neural networks ...
, discovered 14 years later by Giuseppe Moruzzi and
Horace Magoun Quintus Horatius Flaccus (; 8 December 65 BC – 27 November 8 BC),Suetonius, Life of Horace commonly known in the English-speaking world as Horace (), was the leading Roman lyric poet during the time of Augustus (also known as Octavian). The r ...
, Bremer attributed the sleep-wake cycle to the effects of sensory input to the brain. He concluded that sleep is simply a manifestation of a decrease in cortical "tone". The tone is maintained by the continuous flux of sensory information to the brain.


Batini's disproving

Another research in the field of sleep, Batini, questioned Bremer's hypothesis and did an experiment similar to Bremers'. In 1939 Batini's experiment performed his experiment in which he stimulated of different areas of the reticular activating system, and his results concluded that sleep is not dependent on an influx or lack of stimulus from the body. Our bodies do not require input to have or maintain evidence of being awake.


Summary

Although Bremer's hypothesis was ultimately proved flawed, he was still one of pioneers of neurophysiology. Through his work he inspired many to investigate more into the brain, which lead to the discovery of much of what we know now about the anatomy of the human brain and its functions. Bremer also followed up on his research in sleep and did research in things such as the biological clock. The effects of Bremer's insight will be felt throughout the history of neurophysiology.


Notes

{{DEFAULTSORT:Bremer, Frederic 1892 births 1982 deaths Belgian neuroscientists People from Arlon